Refer to
®
HYSYS 3.2
Simulation Basis
Copyright Notice
© 2003 Hyprotech, a subsidiary of Aspen Technology, Inc. All rights reserved.
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Hyprotech reserves the right to make changes to this document or its associated computer program
without obligation to notify any person or organization. Companies, names, and data used in examples
herein are fictitious unless otherwise stated.
Hyprotech does not make any representations regarding the use, or the results of use, of the Software, in
terms of correctness or otherwise. The entire risk as to the results and performance of the Software is
assumed by the user.
HYSYS, HYSIM, HTFS, DISTIL, and HX-NET are registered trademarks of Hyprotech.
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SimBH3.2-B5025-OCT03-O
Table of Contents
HYSYS Thermodynamics ............................................... v
1
2
3
Components ................................................................ 1-1
1.1
Introduction ...........................................................................1-2
1.2
Component List View ............................................................1-4
Fluid Package.............................................................. 2-1
2.1
Introduction ...........................................................................2-2
2.2
Fluid Packages Tab ..............................................................2-3
2.3
Adding a Fluid Package - Example.......................................2-4
2.4
HYSYS Fluid Package Property View ..................................2-7
2.5
COMThermo Property View................................................2-70
2.6
References .........................................................................2-91
Hypotheticals .............................................................. 3-1
3.1
Introduction ...........................................................................3-3
3.2
Hypo Manager ......................................................................3-4
3.3
Adding a Hypothetical - Example..........................................3-5
3.4
Creating a Hypo Group .......................................................3-11
3.5
Hypothetical Component Property View .............................3-23
3.6
Solid Hypotheticals .............................................................3-32
3.7
Cloning Library Components ..............................................3-37
3.8
Hypo Controls .....................................................................3-39
3.9
References .........................................................................3-40
iii
4
HYSYS Oil Manager..................................................... 4-1
4.1
Introduction ...........................................................................4-3
4.2
Oil Characterization ..............................................................4-4
4.3
Petroleum Fluids Characterization Procedure ......................4-9
4.4
Oil Characterization View ...................................................4-13
4.5
Characterizing Assays ........................................................4-16
4.6
Hypocomponent Generation ...............................................4-51
4.7
User Property......................................................................4-66
4.8
Correlations & Installation ...................................................4-70
4.9
TBP Assay - Example .........................................................4-76
4.10 Sulfur Curve - Example.......................................................4-93
4.11 References .......................................................................4-100
5
6
7
iv
Reactions .................................................................... 5-1
5.1
Introduction ...........................................................................5-2
5.2
Reaction Component Selection ............................................5-3
5.3
Reactions ..............................................................................5-6
5.4
Reaction Sets .....................................................................5-32
5.5
Generalized Procedure .......................................................5-40
5.6
Reactions - Example...........................................................5-42
Component Maps......................................................... 6-1
6.1
Introduction ...........................................................................6-2
6.2
Component Maps Tab ..........................................................6-2
6.3
Component Map Property View ............................................6-4
User Properties ........................................................... 7-1
7.1
Introduction ...........................................................................7-2
7.2
User Property Tab ................................................................7-3
7.3
User Property View ...............................................................7-4
A
B
C
Property Methods & Calculations...............................A-1
A.1
Introduction .......................................................................... A-3
A.2
Selecting Property Methods................................................. A-4
A.3
Property Methods ................................................................ A-9
A.4
Enthalpy & Entropy Departure Calculations ...................... A-45
A.5
Physical & Transport Properties ........................................ A-51
A.6
Volumetric Flow Rate Calculations .................................... A-59
A.7
Flash Calculations ............................................................. A-65
A.8
References ........................................................................ A-75
Petroleum Methods/Correlations ................................B-1
B.1
Introduction .......................................................................... B-2
B.2
Characterization Method...................................................... B-2
B.3
References ........................................................................ B-10
Amines Property Package...........................................C-1
C.1 Amines Property Package ................................................... C-2
C.2 Non-Equilibrium Stage Model .............................................. C-5
C.3 Stage Efficiency ................................................................... C-7
C.4 Equilibrium Solubility............................................................ C-9
C.5 Phase Enthalpy.................................................................. C-18
C.6 Simulation of Amine Plant Flowsheets .............................. C-19
C.7 Program Limitations ........................................................... C-23
C.8 References ........................................................................ C-24
Index.............................................................................I-1
v
vi
v
HYSYS Thermodynamics
To comprehend why HYSYS is such a powerful engineering simulation
tool, you need look no further than its strong thermodynamic
foundation. The inherent flexibility contributed through its design,
combined with the unparalleled accuracy and robustness provided by
its property package calculations leads to the representation of a more
realistic model.
Not only can you use a wide variety of internal property packages, you
can use tabular capabilities to override specific property calculations for
more accuracy over a narrow range or use the functionality provided
through ActiveX to interact with externally constructed property
packages. Through the use of Extensibility, you can extend HYSYS so
that it uses property packages that you created within the HYSYS
environment.
The built-in property packages provide accurate thermodynamic,
physical, and transport property predictions for hydrocarbon, nonhydrocarbon, petrochemical, and chemical fluids.
The Thermodynamics development group at Hyprotech has evaluated
experimental data from the world’s most respected sources. Using this
experimental data, a database containing in excess of 1500 components
and over 16,000 fitted binaries has been created. If a library component
cannot be found within the database, a comprehensive selection of
estimation methods is available for creating fully defined hypothetical
components.
HYSYS also contains a powerful regression package that may be used in
conjunction with its tabular capabilities. Experimental pure component
data, which HYSYS provides for over 1,000 components, can be used as
input to the regression package. Alternatively, you can supplement the
existing data or supply a complete set of your own data. The regression
package fits the input data to one of the numerous mathematical
expressions available in HYSYS. This allows you to obtain simulation
results for specific thermophysical properties that closely match your
experimental data.
v
vi
As new technology becomes available to the market place, Hyprotech
welcomes the changes. HYSYS was designed with the foresight that
software technology is ever-changing and that a software product must
reflect these changes. HYSYS has incorporated COMThermo which is an
advanced thermodynamic calculation framework based on Microsofts
COM (Component Object Model) technology. The COMThermo
framework is fully componentized which makes it possible to develop
independent, extensible, customizable, and encapsulated
thermodynamic calculation modules. It acts like a thermodynamic
calculation server which allows users to utilize, supplement, or replace
any of its components.
The framework also encompasses a wide variety of property
calculations, flash methods, databases, etc. The calculation methods
cover all of the thermodynamic calculation packages in HYSYS. In future
releases of HYSYS, the old HYSYS thermodynamic engine will gradually
be replaced by COMThermo.
Simulation Basis Manager
Use the Hot Key CTRL B to reenter the Basis Environment
from any Environment.
One of the important concepts upon which HYSYS is based is that of
environments. The Basis Environment allows you to input or access
information within the Simulation Basis Manager while the other areas
of HYSYS are put on hold. This helps to maintain peak efficiency by
avoiding unnecessary flowsheet calculations. Once you return to the
Build Environment, all changes that were made in the Basis
Environment take effect at the same time. Conversely, all
thermodynamic data is fixed and is not changed as manipulations to the
flowsheet take place in the Build Environment.
Another advantage of the Simulation Basis Environment is the
assurance that all the basic thermodynamic requirements are provided
before a simulation case is built. The minimum information required
before leaving the Simulation Basis Manager is as follows:
• At least one installed fluid package with an attached Property
Package.
• At least one component in the fluid package.
• A fluid package specified as the Default fluid package. This is
automatically done by HYSYS after the first fluid package is
installed.
vi
vii
The Simulation Basis Manager can be accessed at any stage during the
development of a simulation case. When a New Case is created, the first
view that appears is the Simulation Basis Manager. You can also return
to the Basis Environment from the Main or Sub-Flowsheet Environment
at any time to make changes to the thermodynamic information.
You can create as many fluid packages as you like in the Simulation Basis
Manager. This functionality makes it possible for each flowsheet in the
case to be associated with an individual fluid package, thus allowing it to
have its own particular property package and set of components. The
Default fluid package is assigned to each new Sub-Flowsheet that is
created while in the Build Environment. If a different fluid package is
desired, you can re-enter the Basis Environment to perform the required
change.
Provided that changes are made in the Basis Environment, HYSYS
displays a message box each time you re-enter the Main Build
Environment.
Figure 4.1
If HYSYS is left in HOLDING
mode, calculations can be
activated by clicking the Solver
Active icon in the Toolbar.
This provides a means of leaving HYSYS in HOLDING mode so that you
can perform complimentary changes (i.e., new stream compositions,
column specifications) to the flowsheet prior to the Basis modifications
taking effect.
The Simulation Basis Manager property view allows you to create and
manipulate fluid packages in the simulation. Whenever you create a
New Case, HYSYS opens to the Components tab of the Simulation Basis
Manager.
vii
viii
Figure 4.2
In this book, chapters are
devoted to the explanation
of each tab of the
Simulation Basis manager.
The tabs available on the Simulation Basis Manager view are described
in the table below:
The Enter Simulation
Environment button can be
accessed from any of the tabs
on the Simulation Basis
Manager view.
viii
Tab
Description
Components
Allows access to a component list which is associated with a
fluid package. When adding a new component list or editing a
current list, the Component List View opens. This view is
designed to simplify adding components to the case.
Fluid Pkgs
Allows you to create and manipulate all fluid packages for the
simulation case. Also, you can assign a fluid package to each
flowsheet that exists within the case and select a Default fluid
package, which is automatically used for all new flowsheets.
Hypotheticals
Allows individual Hypotheticals and Hypothetical Groups to be
defined for installation into any fluid package.
Oil Manager
Allows access to the Oil Environment where you can input
assay data, cut/blend an oil and define pseudo components for
installation in any existing fluid package.
Reactions
Allows you to install reaction components, create reactions,
create reaction sets, attach reactions to reaction sets and
attach reaction sets to any existing fluid package.
Component Maps
Allows you to specify composition across fluid package (subflowsheet) boundaries.
User Property
Create and make user properties available to any fluid
package.
Components
1-1
1 Components
1.1 Introduction......................................................................................2
1.2 Component List View ......................................................................4
1.2.1
1.2.2
1.2.3
1.2.4
1.2.5
1.2.6
Adding Library Components.....................................................5
Selecting Library Components .................................................8
Manipulating the Selected Components List ..........................13
Adding Electrolyte Components .............................................24
Adding Hypothetical Components ..........................................26
Adding Components from Existing Component Lists .............27
1-1
1-2
Introduction
1.1 Introduction
The Components Manager is accessed by selecting the Components tab
from the Simulation Basis Manager. The Components Manager
provides a location where sets of chemical components being modeled
may be retrieved and manipulated. These component sets are stored in
the form of Component Lists which may be a collection of library pure
components or Hypothetical components.
The Components Manager always contains a Master Component List
that cannot be deleted. The Master Component List contains every
component available from “all” component lists. If you add
components to any other Component List, they are automatically added
to the Master Component List. Also, if you delete a component from the
master, it is deleted from any other Component List that is using it.
Figure 1.1
You cannot associate the
Master Component List to a
fluid package. Add a
component list and associate
it to a fluid package.
1-2
When working with the Fluid Package Manager, components are
associated with Fluid Packages through Component Lists. A Component
List must be selected for each Fluid Package created. For further details
regarding to the use of Component Lists with Fluid Packages, see
Chapter 2 - Fluid Package.
Components
1-3
The Components tab of the Simulation Basis Manager view contains six
buttons which allow you to organize all component lists for the current
case. Each button is described in the following table:
Button
Description
View
Opens the Component List view for the selected Component List. From this
view, you can add, modify, or remove individual components from the
current list.
Add
Allows you to add a new Component List into the case. When clicked, the
Component List view appears and components associated with the case
may be added. New components may be added to the component list by
highlighting the component list name and clicking the View button.
Delete
Allows you to delete a Component List from the case. No warning message
is provided before deleting a list and a deleted Component List cannot be
recovered.
Copy
Makes a copy of the selected (highlighted) Component List. The copied
version is identical to the original, except for the name. This command may
be useful for modifying Component Lists while keeping the original list
intact.
Import
Allows you to import a pre-defined Component List from a disk. When the
Import button is selected, the location dialog window for the component list
file appears. Component Lists have a file extension of (*.cml).
Export
Allows you to export the selected Component Lists (*.cml) to disk. The
exported list file can be retrieved in another case by using the Import
function detailed above.
Refresh
Allows you to reload component data from the database. For example, if
you have a case from a previous version, the data is updated from the older
version to the latest version.
1-3
1-4
Component List View
1.2 Component List View
When adding or viewing an existing Component List from the
Components tab of the Simulation Basis Manager view, the Component
List View is opened.
Figure 1.2
The Add Component tree
configuration allows you to filter
through alternative component lists.
The Name cell displays the name of the
component list being viewed.
The Component List View is designed to simplify adding components to
a Component List. Access is provided to all Library components within
HYSYS, which include the traditional components, electrolytes, defined
Hypotheticals, and other existing lists. The view consists of the following
tabs:
•
1-4
The Selected tab allows you to add components and view their
properties. The Components page view varies according to the
tree configuration selection in the Add Component group.
Components
•
1-5
The Component by Type tab displays all components selected for
the component list by its particular type (traditional, electrolytes,
hypotheticals, etc.) as shown below.
Figure 1.3
1.2.1 Adding Library Components
The Component List View shown previously is encountered when you
are adding Library components to a Component List. Use the Add
Components tree configuration to filter the library components for each
group listed.
The Selected tab view has three main groups:
•
•
•
the Add Component tree
Selected Components group
Components Available in the Component Library group.
Each group is described separately in the following sections.
1-5
1-6
Component List View
Add Component Tree
Add Component Tree
The Add Component group allows you to filter components by type.
Selecting components from the component tree determines the type of
components that are displayed in the Components Available in
Component Library group. A different view is displayed depending on
whether you are adding Traditional, Electrolytes, Hypothetical, or Other
components.
Selected Components Group
Figure 1.4
The Selected Components group shows the list of components that have
been added. The various functions that allow you to manipulate the list
of selected components are listed in the following table:
1-6
Object
Description
Selected
Component List
Contains all the currently installed components for a particular
component list.
Add Pure
Adds the highlighted component(s) from the Components
Available group to the Selected Component List.
Substitute
Swaps the highlighted selected components with the highlighted
available component.
Remove Comp
Deletes the highlighted component from the Selected Component
List.
Components
Object
Description
Sort List
Accesses the Move Components view, where you can change the
order of the selected component list.
View Comp
Accesses the selected component’s identification property view.
1-7
When substituting components, HYSYS replaces the component
throughout the case (i.e., all specifications for the old component are
transferred to the new component). However, the substitution function
does not automatically handle components that are part of a Reaction.
Components Available in the Component Library Group
Figure 1.5
The Components Available in the Component Library group displays
library components depending on the filtered method used. It has
several features designed to make the selection of components as
efficient and convenient as possible.
Object
Description
Match
As you type in this cell, HYSYS filters the component list to
locate the component that best matches your current input.
This depends on the radio button selected.
View Filter button
This button opens the Filters floating view which contains a
range of property packages and component filtering options to
assist in your component selection process. For further details,
refer to Filter Options for Traditional Components.
SimName\ FullName
Synonym\ Formula
These three radio buttons determine the context of your input
in the Match cell.
1-7
1-8
Component List View
Object
Description
Show Synonyms
When this checkbox is activated HYSYS includes known
synonyms for each component in the list.
Cluster
This checkbox is available only when the Show Synonyms
checkbox is checked. By checking the Cluster checkbox, all
synonyms are indented and listed below the component name.
Otherwise, the synonyms are listed alphabetically throughout
the list.
1.2.2 Selecting Library Components
Whenever a component(s) is
highlighted in the Available
List, click the Add Pure button
to move it to the Selected
Component List.
As mentioned previously, library components are selected from the
Components Available in the Component Library group, and placed in
the Selected Components group. There are many ways in which you can
select components for a component list. Once you become familiar with
the available methods for component selection, you can select the
procedure that you find most convenient.
The process of adding components from the component library to the
Selected Components list can be divided into three sub-processes. By
visualizing the process of component selection in this way, you are
made aware of all the available possibilities offered by HYSYS. You can
then adopt the most logical and efficient approach to use each time you
build a case.
For component addition to the component list, the following methods
are recommended:
1-8
1.
Filter the library list.
2.
Select the desired component(s).
3.
Transfer the component(s) to the Selected Components list.
Components
1-9
Filtering the Component List for Traditional Components
A recommended practice for component selection is the use of the
available tools which HYSYS provides for filtering the component
library. This narrows the selection range and allows you to apply one of
the various methods for transferring the selection(s) to the Selected
Components list.
Filtering options for electrolytes and hypotheticals are different and
available in Section 1.2.4 - Adding Electrolyte Components and Section
1.2.5 - Adding Hypothetical Components, respectively.
There are four tools available for filtering the list in the Components
Available in the Component Library group. The filtering tools can be
used independently or in combination and are described in the table
below:
Filtering Tool
Description
Property Package &
Family Type Filters
Filters the list according to your selection of property package
and/or component families. Refer to previous Filter Options
for Traditional Components for further details.
Show Synonyms
Component synonyms appear alphabetically throughout the list
when this checkbox is activated.
Cluster
The Cluster checkbox is available only when the Show
Synonyms checkbox is activated and Match input field is
empty. By activating the Cluster checkbox, all synonyms are
indented and listed below the component name.
Match
This input cell allows type-matching of the component
simulation name, full name, synonym or formula.
When trying to Match a component, HYSYS searches the component
column in the list for whichever radio button is selected:
Radio Button
Description
SimName
This option matches the text entered into the Match input to the
name used within the simulation.
Full Name/
Synonym
This option may match the components full name or a synonym of
the SimName. It is typically a longer name.
Formula
Use this option when you are not sure of the library name, but know
the formula of the component.
1-9
1-10
Component List View
By using the Match input cell, you can access any component within the
HYSYS library that is accessible under the currently selected Property
Package. You can make the Match field active by selecting it or by using
the ALT M hot key.
The Match input cell accepts keyboard input, and is used by HYSYS to
locate the component in the current list which best matches your input.
The first character of the filtered component names must agree with
first character of the listed component name. Subsequent characters in
the Match cell must appear somewhere in each listed component name.
Other than the first character, any number of unmatched characters can
appear within the names of the listed components.
If the component you want to add is Water, type H2 in the Match cell.
HYSYS filters the list of available Library Components to only those that
match your current input string. The first component in the list, H2, is
an exact match of your current input and therefore, is highlighted.
Notice that H2O is available in the list even though you have entered
only H2.
Figure 1.6
Since Hydrogen is not the component of choice, you can continue to
reduce the list of available library component options by typing in the
character O after the H2 in the Match cell.
1-10
Components
1-11
Filter Options for Traditional Components
The floating Filter view is accessed by clicking the View Filters button
from Component List View. It allows access to the Property Package
filter and Family Type filter options.
The Property Package Filter group filters components based on their
compatibility with the selected property package. Once a property
package is selected, the Recommended Only checkbox works as follows:
•
•
If the Recommended Only checkbox is selected, HYSYS only
displays (in the component library list) components that are
recommended with the chosen property package.
If the Recommended Only checkbox remains un-selected, all the
components in the HYSYS library are displayed in the component
library list. An ‘x’ is shown beside each component that HYSYS
does not recommend for the selected property package,
however, you may still select these components if you want.
The Property Package Filter is only a component selection filtering tool
and does not associate a Fluid Package with the component list (this is
accomplished within the Fluid Package Manager).
The Family Type Filter group allows HYSYS to filter the list of available
components to only those belonging to a specific family. The Use Filter
checkbox, when selected, toggles the Family Type Filter options On and
Off. By default, all checkboxes in the Family Filter group are deactivated.
You can identify which families should be included in the list of
available components by selecting the desired checkbox(es). The All
button activates all checkboxes, and the Invert button toggles the status
of each checkbox individually. For example, if you activate all of the
checkboxes, and then want to quickly deactivate them, simply click the
Invert button. If you only had the Hydrocarbons and the Solids options
activated and you clicked the Invert button, these two options are
deactivated and the remaining options are activated.
1-11
1-12
Component List View
Selecting the Component(s)
After the list of Library Components are filtered, you can see the desired
component among the displayed components. Use one of the following
available methods to highlight the component(s) of choice described in
the following table:
Selection Method
Description
Mouse
Place the cursor over the desired component and press the
primary mouse button.
Keyboard
Use the TAB key or SHIFT TAB combination to move the active
location into the list of components.
Whenever the list of components is filtered, the highlight is placed on
the first component in the reduced list. If you use the keyboard
commands to access the list of components, you may have to move the
highlight if the first component is not desired.
To move through the Components Available in the Component Library
group, use one of the following methods:
Method
Description
Arrow Keys
Move the highlight up or down one line in the component list.
Page Up/Page
Down
Use these keyboard keys to move through the list an entire page at
a time.
Home/End
The HOME key moves to the start of the list and the END key moves to
the end of the list.
Scroll Bar
With the mouse, use the scroll bar to navigate through the list.
Transferring the Component(s)
After the Library Component list is filtered and the desired
component(s) highlighted, transfer the selection(s) to the Selected
Components list. Use one of the following methods:
•
•
•
Click the Add Pure button
Press the ENTER key
Double-click on the highlighted item. This option only works for a
single component selection.
The methods are the same whether you are adding traditional
components, electrolytes, hypotheticals, or other components.
1-12
Components
1-13
1.2.3 Manipulating the Selected Components
List
After adding the components to the Selected Components list, you can
substitute, remove, sort and view components. These methods apply to
traditional library components, electrolytes, hypotheticals, and other
components.
To demonstrate the manipulation functions, the Selected Components
group shown below is used for reference purposes.
Figure 1.7
Removing Selected Components
Refer to Chapter 3 Hypotheticals for detailed
information on Hypothetical
components.
You can remove any component(s) from the Selected Components list
by the following steps:
1.
Highlight the component(s) you want to delete.
2.
Click the Remove button, or press the DELETE key.
For Library components, HYSYS removes the component(s) from the
Selected Components list and places back in the Components Available
in the Component Library list. Since Hypothetical components are
shared among Fluid Packages, there is no actual transfer between the
lists. (i.e., The Hypo always appears in the Available group, even when it
is listed in the selected Components list.)
1-13
1-14
Component List View
Substituting Components
You can only substitute one
component at a time. Even
though HYSYS allows you to
highlight multiple components,
the substitution only involves
the first highlighted
component.
When substituting components, HYSYS replaces the component
throughout the case (i.e., all specifications for the old component are
transferred to the new component). However, the substitution function
does not automatically handle components which are part of a
Reaction.
You can substitute a component in the selected Component List with
one in the Components Available in the Component Library list by using
the following procedure:
1.
From the selected Component List, highlight the component you
want to remove.
2.
In the Available Component list, highlight the component to be
substituted.
3.
Click the Substitute button.
4.
The removed component is returned to the Available Component
list and the substituted component is placed in the Selected
Component List.
Sorting a Component List
When there are components in the Selected Components group you can
use the Sort List button to rearrange the component order.
Figure 1.8
1-14
Components
1-15
Using the view shown in Figure 1.8, the sorting procedure is illustrated
below:
You can highlight and move
multiple components.
1.
Click the Sort List button, and the Move Components view appears.
2.
From the Component(s) to Move group, select the component you
want to move. In this example, Methane is selected.
3.
From the Insert Before group, highlight the component before
which Methane is to be inserted. In this case, Propane is
highlighted.
4.
Click the Move button to complete the move. Methane is inserted
before Propane in the component list, and Ethane is forced to the
top of the list, followed by Methane, Propane, and n-Butane.
5.
When you have completed the sorting, click the Close button to
return to the Components tab.
Viewing Components
You can also examine the
property view for any
component in the Selected
Component List by doubleclicking on the component.
Once a component is added to the Selected Components list, the View
Component button becomes active. The View Component button
accesses the Pure Component property view allowing you to view and
edit properties of the specified component.
The property views are different and are specific to the type of
component selected. Pure library components and hypothetical
components share the first type of property view. The difference
between the two is that you cannot “directly” modify the properties in
the pure components Property View, whereas, in the hypotheticals you
can. The Edit Properties feature allows you to edit pure component and
solid properties. For more information on hypotheticals, refer to
Chapter 3 - Hypotheticals.
The second property view is shared by pure component solids and
hypothetical solids. Again you cannot “directly” modify the pure
component solid properties, whereas, hypotheticals can be edited
directly.
The electrolytes property view is the same as the edit properties feature
for library components. Although, the electrolyte properties are set by
OLI systems and cannot be modified like traditional components. For
more information on electrolytes, refer to Section 1.2.4 - Adding
Electrolyte Components.
1-15
1-16
Component List View
Each view consists of five tabs. Throughout the tabs the information is
displayed in red, blue and black. Values displayed in red are estimated
by HYSYS. Values displayed in blue are user supplied. Black values
represent calculated values or information that is provided by HYSYS.
Pure Component Property View
You can also view a
component by right-clicking
on it and selecting View.
In this example, Methane and Carbon are used by clicking the View
Component button, which opens the following traditional pure
component and Solid pure component property views, respectively:
Figure 1.9
ID Tab
The ID tab is the first tab in the property view. The black values in the
Component Identification group represent information that is provided
by HYSYS. The User ID Tags are used to identify your component by a
user specified tag number. You can assign multiple tag numbers to each
component.
1-16
Components
1-17
Critical Tab & Props Tab
The Critical Tab displays Base and Critical Properties. The properties for
pure components are supplied by HYSYS and are read-only. However,
you can edit these properties using the Edit Properties button.
The Component Property view for solid components does not have
critical properties and therefore does not require the Critical tab. An
alternate tab called the Props tab which displays default values for Solid
properties and Coal Analysis is included. These properties can also be
edited using the Edit Properties button.
Point Tab
Additional Point properties are given by HYSYS for the Thermodynamic
and Physical Props and the Property Package Molecular Props. The pure
component properties differ from the solid properties.
The solid properties depend only on the Heat of Formation and
Combustion. These properties may be altered by selecting Point
properties in the Edit Properties view.
TDep Tab
The temperature Dependent Properties for pure components are shown
in this tab. HYSYS provides the minimum temperature, maximum
temperature and coefficients for each of the three calculation methods.
The difference between pure components and solid pure components is
that solids do not participate in VLE calculations. Their vapour pressure
information is, by default, set to zero. However, since solid components
do affect Heat Balances, the Specific Heat information is used. The
properties may be edited by selecting the Edit Properties button.
1-17
1-18
Component List View
UserProp & PSD Tabs
See Chapter 7 - User
Properties for more
information.
The UserProp tab displays user specified properties. User properties
must be specified on the UserProperty tab in the Simulation Basis
Manager view. Once a user property is specified there, you can view and
edit UserProp on this component view.
The PSD tab displays the particle size distribution for solids. It allows
the user to specify PSDs and calculate various mean and modal
diameters for the entered PSD.
To edit a PSD, click the Edit Properties button to open the Editing
Properties for Component view, select Type radio button in the Sort By
group, and select Particle Size Distribution from the tree browser. The
options available for edit the PSD appears on the right side of the Editing
Properties for Component view.
Figure 1.10
1-18
Components
1-19
A PSD can be specified in three ways:
Input PSD Group
Description
User-Defined
Discrete
Allows the user to enter particle diameter vs distribution values
over the range of the distribution. To enter the distribution, Select
the Edit Discrete PSD button. The entered distribution can be a
Composition Basis with mass percent or number percent data and
can be InSize, cumulative Undersize or cumulative Oversize as an
Input Basis. Once a discretized PSD is entered, the user can have
other types of PSD fitted to it. These fits are displayed in the Fit
Type group. The selected fit can be changed by regenerating the fit
at any time.
Log-probability
Is a two-parameter statistical representation which allows the user
to specify the mean and standard deviation of the PSD.
Rosin-Rammler
Is a two-parameter statistical representation which allows the user
to specify the Rosin-Rammler model diameter and spread
parameter of the PSD.
The input information required for each Input PSD are as follows:
Input PSD Group
Input Information Required
User-Defined
Discrete
The PSD requires PSD name, basis, particle density and number
of points to use in fitted PSDs. The distribution requires particle
diameters (including minimum diameter) and either InSize,
Undersize or Oversize distribution points.
Log-probability
The PSD requires PSD name, basis, particle density and number
of points to use in generating the PSD. The distribution requires
mean diameter and standard deviation.
Rosin-Rammler
The PSD requires PSD name, basis, particle density and number
of points to use in generating the PSD. The distribution requires
modal diameter and spread parameter.
The user has the choice between using the User-Defined Discrete or one
of the statistical distribution methods. The statistical methods (Log
Probability & Rosin-Rammler) may be preferred over the discrete
method if any of the following occurs:
•
•
•
A number of particle size measurement devices give the
distribution as a statistical fit.
Certain physical process tend to give rise to distributions that are
described well by a statistical distribution. For example,
processes involving high shear (e.g. crushing of coal, atomization
of liquids in a two-fluid nozzle) tend to give size distributions that
can be readily described by a Rosin-Rammler distribution.
By using a statistical distribution, it is easier to extend the
distribution to lower and higher size ranges. For many design
processes involving size distributions, it is the values of the
distribution at these 'tails' that have most influence when trying to
optimize the design. Therefore, the accuracy with which these
'tails' can be described is important.
1-19
1-20
Component List View
The Fit Type group for the User-Defined Discrete Input allows users to
fit a distribution to the entered discrete data. The fitting improves the
accuracy of any calculations made by it.
•
•
It increases the number of discrete steps over which a size
distribution can be described. The more steps, mean smaller
steps which means more accuracy when interpolating, etc.
It provides more data at the extremes (‘tails’) of the distribution,
again improving accuracy.
The fit type used is based on which provides the closest fit to the data.
The fitting alogorithm displays a dialog with six fits to the data. The
AutoFit selects one fit for the data automatically, and the NoFit does not
fit the data. The Standard and Probability fit types are lagrangian
interpolations on the entered data, but one works on the raw data while
one works on a probability transformation of the data. That is, the
distribution values are transformed to the linear equivalents used in
plotting against a probability axis.
The other two fits are a log-probability and a Rosin-Rammler
distribution. For these two fits, the value of R2 (the fit coefficient) is
given and the closer this is to 1 the better the fit. Ultimately, it is up to
the user to choose the best fit and is often based on the visual
appearance of the fitted distibutions compared to the entered one. One
limitation to PSD is that the particle diameters cannot be specified as
sieve mesh sizes.
Edit Properties
The Edit Properties button allows the user the flexibility of viewing and
modifying properties for traditional and hypothetical components.
Electrolyte component properties are specified by OLI Systems which
may only be viewed. The Edit Properties View can be accessed on three
different levels and are shown below:
•
•
•
1-20
Component level. Double-click on any component or right-click
and select View. Click the Edit Properties button.
Fluid Package level. Click the Edit Properties button on the Fluid
Package view.
Stream level. Select a stream which is not a product stream.
Click the Edit Properties button on the Composition page.
Components
1-21
The Component level Edit Properties view is shown below for methane.
Figure 1.11
The properties can be sorted using the Sort By group on any level.
Sort By
Description
Property Name
Sort through properties by Property Name.
Group
Sort through properties by Groups. This includes Thermo,
Prop Pkg, Physical, Cold, Solid, etc.
Type
Sort through Point, Curve, Distribute, PSD, and Hydrate
properties.
Modify Status
Sort through properties which are modified in the specific
Component, Fluid Pkg, or Stream.
The edit Properties feature is flexible in that it allows you to edit
properties on the component, fluid package, or stream levels. The
component level is the highest and allows you to edit properties
throughout your case. Any changes at this level correspond to a global
change to all fluid packages using the particular component. The initial
value stored at this level for any given component is considered the
’default’ property value.
1-21
1-22
Component List View
At the component level, the reset options are described below.
Component Level
Reset
Description
Reset selected
property to library
default
Resets the selected property to the library or original default
value for this component. This button is active only if a
component is modified on the component level.
Reset all properties to
library default
Resets all properties to library or original default values for
this component. This button is active only if a component is
modified on the component level.
Reset selected
property for all users
of this component
Clears local changes to the selected property for all users of
this component. Users are defined by changes in the Fluid
pkg and stream levels.
Reset all properties
for all users of this
component
Clears local changes to all properties for all users of this
component. Users are defined by changes in the Fluid pkg
and stream levels.
The second level is the fluid package level which allows you to edit
properties specific to a fluid package. This allows the flexibility of having
different property values for different fluid packages throughout the
case. Any changes at this level corresponds to a change for any
flowsheet using this fluid package.The reset options for the fluid pkg
level are described below:
Fluid Pkg Level Reset
Description
Reset selected prop
vector to components
default
Clears the selected property vector within this fluid package
and resets it to the component level value.
Reset all props to
components default
Clears all changed property vectors within this fluid package
and resets them to the component level values.
Reset selected
property for all users
of this fp
Clears local changes to selected property vector for all users
of this fluid package. The user is defined as the stream level
property selected, which is overwritten with current fluid
package value.
Reset all properties
for all users of this fp
Clears local changes to all properties for all users of this fluid
package. The users are defined as the stream level
properties, which are overwritten with current fluid package
values.
The stream level allows you to edit properties specific to input streams
of the case. Changes made at this level enable one to modify a particular
component’s property for a particular stream. This allows the flexibility
of properties to dynamically change across the flowsheet.
1-22
Components
1-23
The reset options are listed below and are active if you modify a
property value at the stream level.
Stream Level Reset
Description
Reset Selected Prop
Vector to FP Default
Clears selected property vector and reset it to the fluid
package level value for this stream.
Reset All Props to FP
Default
Clears all changed property vectors and reset them to the
fluid package values for this stream.
The properties for the stream are accessible from the stream level editor.
However, only the feed stream properties are modifiable.
Keep in mind that any property vector changes at the Stream level
supercede changes at the fluid package level. For example, if a stream is
trying to access a particular component’s ’Point’ property value and the
property vector is contained in the stream’s local property slate, the
local value is used. If the property vector does not exist locally, then it
calls up to the fluid package’s property state for the particular property
vector and uses this value if it exists. If the property vector does not exist
at the fluid package level, then the initial Component level value is used.
1-23
1-24
Component List View
1.2.4 Adding Electrolyte Components
Electrolytes can be added to the component list in the Component List
View. In the Add Component group of the Selected tab, select the
Electrolyte page located as the subgroup of the Components
configuration.
The view is filled with information on electrolytes as shown below.
Figure 1.12
The methods for adding, substituting, removing, and sorting
components are common for all components on the selected tab. The
filtering options for Electrolytes which are described in the following
table:
Refer to Filtering the
Component List for
Traditional Components for
additional information on
using the Match field to filter
the component list for
traditional components.
1-24
Filter
Description
Match
This input cell allows type-matching of the component simulation
name, full name / synonym, or formula based on the ratio button
selected.
None
No electrolyte components exist or match your selection in the view.
You need to acquire an additional license to view the electrolyte
database.
Components
Refer to the following sections
in the HYSYS OLI Interface
Guide for more information on
the OLI databases:
• Section 1.8.1 - Full
Database
• Section 1.8.2 - Limited
Database
• Section 1.8.3 - Special
Databases
• Section 1.8.4 - Private
User Databases - OLI
Data Service
Filter
Description
Full
The full database contains thousands of species in water based on
the OLI system database.
Limited
This database contains approximately 1,000 components which are
of most interest to process industries.
1-25
You can select or provide additional electrolyte component databases to
simulate special aqueous-based chemical systems. HYSYS
supports three special databases: GEOCHEM, LOWTEMP, and
REDOX. You can access those special databases by clicking on the
Additional Database button, and select the desired special databases
from the Special Databank group in the OLI_Electrolyte Additional
Database view. The use of GEOCHEM, LOWTEMP, and REDOX
databases must combine with the choice of Full Databank. You can
also supply your own OLI private databank to suit the need of your
simulation case.
To get a comprehensive list of the Full, and GEOCHEM database
components, refer to Appendix A.1 - Listing of the Full HYSYS OLI
Interface Database and Appendix B.1 - Listing of the HYSYS OLI
Interface GEOCHEM Database, of the HYSYS OLI Interface Reference
Guide.
1-25
1-26
Component List View
1.2.5 Adding Hypothetical Components
Refer to Section 3.5 Hypothetical Component
Property View for details on
the various Component
property view tabs.
Hypotheticals can be added to a component list through the
Components List View. In the Add Components group of the Selected
tab, select the Hypothetical page from the tree configuration list. The
Components List View is filled with information appropriate to the
addition of Hypothetical components.
Figure 1.13
Refer to Chapter 3 Hypotheticals for more
detailed information to Add
and modify Hypothetical
components.
1-26
Some of the features from the Selected tab are common to both the
selection of Hypotheticals and Library components. Items specific to
Hypotheticals are described in the following table:
Object
Description
Add Group
Adds all the Hypothetical components in the Selected selection in
the Hypo Group list current to the current component list.
Add Hypo
Adds the currently selected Hypothetical in the Hypo Component list
to the Current Component List.
Hypo Group
Displays all the Hypo Groups available to the current component list.
Hypo
Components
Displays all the Hypothetical components contained in the currently
selected Hypo Group.
Hypo Manager
Accesses the Hypotheticals tab of the Simulation Basis Manager,
from which you can create, view, or edit Hypotheticals.
Components
Object
Description
Quick Create a
Hypo Comp
A short-cut for creating a regular Hypothetical component and adds
it to the currently selected Hypo Group and opens its property view.
Quick Create a
Solid Hypo
component
A short-cut for creating a solid Hypothetical component and adds it
to the currently selected Hypo Group and opens its property view.
1-27
While you can add Hypos to a Component List from the Selected tab,
this is merely a short-cut. To access all features during the creation of
Hypotheticals and Hypothetical groups, you should access the
Hypotheticals tab of the Simulation Basis Manager.
1.2.6 Adding Components from Existing
Component Lists
Components can be added from other component lists by using the
Other List option. In the Add Components group, select the Other list.
The Components tab is redrawn with information appropriate to
accessing components from alternate component lists.
Figure 1.14
1-27
1-28
Component List View
The Existing Components group displays a list of all available
component lists loaded into the current case. Highlighting a component
list name displays its associated group of components in the
Components in Selected Component List.
To transfer a component from an existing component list, simply
highlight the component name in the list and click the Add button. The
highlighted component is added to the Selected Components list.
1-28
Fluid Package
2-1
2 Fluid Package
2.1 Introduction......................................................................................2
2.2 Fluid Packages Tab .........................................................................3
2.3 Adding a Fluid Package - Example ................................................4
2.4 HYSYS Fluid Package Property View ............................................7
2.4.1
2.4.2
2.4.3
2.4.4
2.4.5
2.4.6
2.4.7
2.4.8
Set Up Tab................................................................................7
Parameters Tab ......................................................................20
Binary Coefficients Tab...........................................................32
Stability Test Tab ....................................................................40
Phase Order Tab ....................................................................44
Reactions Tab.........................................................................46
Tabular Tab.............................................................................47
Notes Tab ...............................................................................69
2.5 COMThermo Property View ..........................................................70
2.5.1
2.5.2
2.5.3
2.5.4
Set Up Tab..............................................................................71
Parameters Tab ......................................................................82
Binary Coefficients Tab...........................................................84
Stability Test Tab ....................................................................87
2.6 References .....................................................................................91
2-1
2-2
Introduction
2.1 Introduction
In HYSYS, all necessary information pertaining to pure component flash
and physical property calculations is contained within the Fluid
Package. This approach allows you to define all the required
information inside a single entity. There are four key advantages to this
approach and are listed below:
•
•
•
•
All associated information is defined in a single location, allowing
for easy creation and modification of the information.
Fluid Packages can be exported and imported as completely
defined packages for use in any simulation.
Fluid Packages can be cloned, which simplifies the task of
making small changes to a complex Fluid Package.
Multiple Fluid Packages can be used in the same simulation;
however, they are all defined inside the common Simulation
Basis Manager.
In this chapter, all information concerning the fluid package are
covered. This includes the basic procedure for creating a fluid package
by using both traditional HYSYS and COMThermo thermodynamics.
Finally, information on the Fluid Package property view is provided for
each of the following tabs:
•
•
•
•
•
•
•
•
Refer to Chapter 1 Components for further
details on the Components
Manager.
2-2
Set Up
Parameters
Binary Coefficients
Stability Test
Phase Order
Reactions (Rxns)
Tabular
Notes
It should be noted that individual components are not added within the
Fluid Package Manager. Instead, component selection is handled
independently in the Basis Manager through the Components tab. The
Components Manager provides a general location where sets of
chemical components being modeled may be retrieved and
manipulated.
Fluid Package
2-3
2.2 Fluid Packages Tab
You must define at least one
fluid package prior to entering
the Simulation Environment.
The next tab of the Simulation Basis Manager view is the Fluid Packages
(Fluid Pkgs) tab. When you create a New Case, HYSYS displays the Fluid
Pkgs tab, as shown below:
Figure 2.1
When a New Case is created,
only the Add and Import
buttons are available.
Refer to Section 2.4 - HYSYS
Fluid Package Property
View for details on what
information you can edit by
clicking the View button.
For details concerning the
importing and exporting
functionality, refer to Section
7.24.7 - Exporting/Importing
Workbook Tabs in the User
Guide.
In the Current Fluid Packages group, there are six buttons that allow you
to organize all Fluid Packages for the current case and are described
below:
Button
Description
View
This is only active when a fluid package exists in the case. It
allows you access the property view for the selected fluid
package.
Add
Allows you to install a new fluid package into the case.
Delete
Allows you to delete a fluid package from the case. When you
delete a fluid package, HYSYS displays a warning, and asks you
to verify that you want to delete the package. You must have at
least one fluid package for your case at all times.
Copy
Makes a copy of the selected fluid package. Everything is
identical in this copied version, except the name. This is a useful
tool for modifying fluid packages.
Import
Allows you to import a pre-defined fluid package from disk. Fluid
packages have the file extension .fpk.
Export
Allows you to export the selected fluid package (*.fpk) to disk.
The exported fluid package can be retrieved into another case, by
using its Import function.
2-3
2-4
Adding a Fluid Package - Example
Changing the default package
only changes those fluid pkgs
that are currently set to use the
default fluid package. That is,
any operation or stream which
is not set to the default fluid
package is not modified.
Refer to Chapter 12 - Logical
Operations in the Operations
Guide for detailed information
on the stream cutter object and
fluid package transitioning.
The Flowsheet - Fluid Pkg Associations group lists each Flowsheet in the
current simulation along with its associated Fluid Package. You can
change the associations between Flowsheets and which Fluid Pkg To
Use in this location. You can also specify a default fluid package by
selecting a package in the Default Fluid Pkg drop-down list. HYSYS
automatically assigns the Default Fluid Package to each unit operation,
SubFlowsheet or columns using the default fluid package in the
simulation. Selecting a alternative fluid package from the Basis Manager
view allows you to transition or switch between fluid pkgs anywhere in
the flowsheet with the addition of the stream cutter object.
2.3 Adding a Fluid Package Example
When you click the Add button from the Simulation Basis Manager
view, HYSYS opens the Fluid Package property view to the Set Up tab.
The Fluid Package view is based on the traditional HYSYS
Thermodynamics.
Figure 2.2
You can check the COMThermo checkbox to
access the COMThermo option in HYSYS.
2-4
Fluid Package
A complete description of
each page of the Fluid
Package property view is
given in Section 2.4 - HYSYS
Fluid Package Property
View.
The order of the tabs in the Fluid Package property view are tied to the
sequence of defining a Fluid Package using HYSYS thermodynamics.
•
For further details relating to
Component Lists and
component selection, refer to
Chapter 1 - Components.
•
•
•
Refer to Chapter 5 Reactions for information on
the Reaction Manager.
2-5
•
•
•
•
On the Set Up tab, select a Property Package for the case from
the Property Package Selection group. You can filter the list of
Property Packages by selecting a radio button in the Property
Package Filter group. You must also select a Component List for
the case from the Component List Selection group. Component
Lists are built in the Simulation Basis Manager and may contain
library, hypothetical, and electrolyte components.
Depending on the Property Package selected, you may need to
specify additional information, such as the Enthalpy and Vapour
Model, Poynting Correction factor, etc.
Depending on the Property Package selected you may need to
supply additional information based on the selected components.
This is done on the Parameters tab.
If necessary, specify the binary coefficients on the Binary Coeffs
tab. As an alternative to supplying binaries, you may want to have
estimates made for the selected components.
If necessary, instruct HYSYS how to perform Phase Stability
tests as part of the flash calculations on the Stab Test tab.
Define any reactions and reaction sets for the fluid package or
access the Reaction Manager on the Rxns tab.
On the Tabular tab, you can access the Tabular Package for the
equation based representation of targeted properties.
The final tab on the Fluid Package property view is the Notes tab,
where you can supply descriptive notes for the new Fluid
Package.
If you click the COMThermo checkbox in the Advanced
Thermodynamics group, HYSYS opens the Fluid package property view
to the Set Up tab. The Fluid Package view is based on the
COMThermodynamics framework.
Figure 2.3
2-5
2-6
Adding a Fluid Package - Example
The order of the tabs in the Fluid Package property view are similar to
the traditional HYSYS Thermodynamics as above except for the
following:
•
•
•
•
•
2-6
On the Set Up tab, select a model case from the Model Selection
group for the vapor and liquid phase.
Depending on the model selected, you may specify additional
information. For example, in the Model Options group select the
calculation methods for Enthalpy and Entropy, Cp, etc., using the
drop-down list.
Depending on the Model selected, you may need to supply
additional information based on the selected components. This is
done on the Parameters tab.
If necessary, specify the binary coefficients on the Binary Coeff
tab. As an alternative to supplying binaries, you may want to have
estimates made for the selected components.
If necessary, instruct HYSYS-COMThermo how to perform Phase
Stability tests as part of the flash calculations on the Stab Test
tab.
Fluid Package
2-7
2.4 HYSYS Fluid Package Property
View
Refer to Section 2.5 COMThermo Property View
for more information on
Advanced Thermodynamics.
The Fluid Package property view consists of eight tabs and is based on
the traditional HYSYS thermodynamics. Among these tabs is all the
information pertaining to the particular Fluid Package.
Figure 2.4
Additional information may be displayed in this space
depending on the Property Package selection.
Select a property
package for the fluid
package using the
property package filter.
Select a Component List
here. It is not
recommended to use the
Master Component List.
Removes the Fluid Package from
the case. You must confirm that you
want to delete the Fluid Package
You can input a
name for the Fluid
Package in this cell.
The selected base
Property Package type is
shown in this status bar.
Select the button to
edit properties at the
fluid package level.
2.4.1 Set Up Tab
The Set Up tab is the first tab of the Fluid Package property view. When
you create a new Fluid Package, the Fluid Package view appears as
shown above. The Set Up tab contains the Property Package Selection,
Component List Selection, Property Package Filter and
Thermodynamics groups. Once a Property Package is selected,
additional information and options may be displayed to the right of the
Property Package Selection group. This is shown above with the EOS
Enthalpy Method Specification group for the Peng-Robinson property
package. The information that is displayed is dependent on the selected
Property Package.
2-7
2-8
HYSYS Fluid Package Property View
The following sections provide an overview of the various Property
Packages, as well as details on the various groups that appear on the Set
Up tab.
Property Package Selection
In the Property Package Selection group, you have access to the list of all
the Property Methods available in HYSYS and to the Property Package
Filter group.
The Property Package Filter allows you to filter the list of available
property methods, based on the following criteria:
Filter
Description
All Types
All the Property Packages appear in the list.
EOSs
Only Equations of State appear in the list.
Activity Models
Only Liquid Activity Models appear in the list.
Chao Seader Models
Only Chao Seader based Semi Empirical methods are
displayed.
Vapour Pressure
Models
Vapour pressure K-value models are shown in the list.
Miscellaneous
Models that do not fit into any of the above 4 categories
(i.e., excluding All) are displayed.
For more detailed information about the property packages available in
HYSYS, refer to Appendix A - Property Methods & Calculations.
Equations of State
For oil, gas and petrochemical applications, the Peng-Robinson
Equation of State is generally the recommended property package.
Hyprotech’s enhancements to this equation of state enable it to be
accurate for a variety of systems over a wide range of conditions. It
rigorously solves most single phase, two phase and three-phase systems
with a high degree of efficiency and reliability.
2-8
Fluid Package
2-9
All equation of state methods and their specific applications are
described below:
EOS
Description
GCEOS
This model allows you to define and implement your own
generalized cubic equation of state including mixing rules and
volume translation.
Kabadi Danner
This model is a modification of the original SRK equation of state,
enhanced to improve the vapour-liquid-liquid equilibria
calculations for water-hydrocarbon systems, particularly in dilute
regions.
Lee-Kesler
Plocker
This model is the most accurate general method for non-polar
substances and mixtures.
Peng-Robinson
This model is ideal for VLE calculations as well as calculating
liquid densities for hydrocarbon systems. Several enhancements
to the original PR model were made to extend its range of
applicability and to improve its predictions for some non-ideal
systems. However, in situations where highly non-ideal systems
are encountered, the use of Activity Models is recommended.
PRSV
This is a two-fold modification of the PR equation of state that
extends the application of the original PR method for moderately
non-ideal systems.
SRK
In many cases it provides comparable results to PR, but its range
of application is significantly more limited. This method is not as
reliable for non-ideal systems.
Sour PR
Combines the PR equation of state and Wilson’s API-Sour Model
for handling sour water systems.
Sour SRK
Combines the Soave Redlich Kwong and Wilson’s API-Sour
Model.
Zudkevitch Joffee
Modification of the Redlich Kwong equation of state. This model
has been enhanced for better prediction of vapour-liquid equilibria
for hydrocarbon systems, and systems containing Hydrogen.
Activity Models
Although Equation of State models have proven to be very reliable in
predicting the properties of most hydrocarbon based fluids over a wide
range of operating conditions, their application is limited to primarily
non-polar or slightly polar components. Highly non-ideal systems are
best modeled using Activity Models.
2-9
2-10
HYSYS Fluid Package Property View
The following Activity Model Property Packages are available:
Activity Model
Description
Chien Null
Provides a consistent framework for applying existing Activity
Models on a binary by binary basis. It allows you to select the
best Activity Model for each pair in your case.
Extended NRTL
This variation of the NRTL model allows you to input values for
the Aij, Bij, Cij, Alp1ij and Alp2ij parameters used in defining the
component activity coefficients. Apply this model to systems:
• with a wide boiling point range between components.
• where you require simultaneous solution of VLE and LLE,
and there exists a wide boiling point range or concentration
range between components.
General NRTL
This variation of the NRTL model allows you to select the
equation format for equation parameters: τ and α. Apply this
model to systems:
• with a wide boiling point range between components.
• where you require simultaneous solution of VLE and LLE,
and there exists a wide boiling point or concentration range
between components.
2-10
Margules
This was the first Gibbs excess energy representation developed.
The equation does not have any theoretical basis, but is useful for
quick estimates and data interpolation.
NRTL
This is an extension of the Wilson equation. It uses statistical
mechanics and the liquid cell theory to represent the liquid
structure. It is capable of representing VLE, LLE, and VLLE phase
behaviour.
UNIQUAC
Uses statistical mechanics and the quasi-chemical theory of
Guggenheim to represent the liquid structure. The equation is
capable of representing LLE, VLE, and VLLE with accuracy
comparable to the NRTL equation, but without the need for a nonrandomness factor.
van Laar
This equation fits many systems quite well, particularly for LLE
component distributions. It can be used for systems that exhibit
positive or negative deviations from Raoult's Law, however, it
cannot predict maxima or minima in the activity coefficient.
Therefore it generally performs poorly for systems with
halogenated hydrocarbons and alcohols.
Wilson
First activity coefficient equation to use the local composition
model to derive the Gibbs Excess energy expression. It offers a
thermodynamically consistent approach to predicting multicomponent behaviour from regressed binary equilibrium data.
However the Wilson model cannot be used for systems with two
liquid phases.
Fluid Package
2-11
Chao Seader & Grayson Streed Models
The Chao Seader and Grayson Streed methods are older, semi-empirical
methods. The Grayson Streed correlation is an extension of the Chao
Seader method with special emphasis on hydrogen. Only the
equilibrium data produced by these correlations is used by HYSYS. The
Lee-Kesler method is used for liquid and vapour enthalpies and
entropies.
Model
Description
Chao Seader
Use this method for heavy hydrocarbons, where the pressure is less
than 10342 kPa (1500 psia), and temperatures range between 17.78 and 260 °C (0-500 °F).
Grayson Streed
Recommended for simulating heavy hydrocarbon systems with a
high hydrogen content.
Vapour Pressure Models
Vapour Pressure K-value models may be used for ideal mixtures at low
pressures. Ideal mixtures include hydrocarbon systems and mixtures
such as ketones and alcohols, where the liquid phase behaviour is
approximately ideal. The models may also be used as first
approximations for non-ideal systems. The following vapour pressure
models are available:
Vapour Pressure
Models
Description
Antoine
This model is applicable for low pressure systems that behave
ideally.
Braun K10
This model is strictly applicable to heavy hydrocarbon systems at
low pressures. The model employs the Braun convergence
pressure method, where, given the normal boiling point of a
component, the K-value is calculated at system temperature and
10 psia (68.95 kPa).
Esso Tabular
This model is strictly applicable to hydrocarbon systems at low
pressures. The model employs a modification of the MaxwellBonnel vapour pressure model.
2-11
2-12
HYSYS Fluid Package Property View
Miscellaneous
The Miscellaneous group contains Property Packages that are unique
and do not fit into the groups previously mentioned.
Amines is an optional Property
Package. Contact your
Hyprotech representative for
further information. For more
information on the package
see Appendix C - Amines
Property Package.
For more information on the
OLI_Electrolyte property
package, refer to Section 1.6
- HYSYS OLI_Electrolyte
Property Package in the
HYSYS OLI Interface
Reference Guide.
Property Package
Description
Amine Pkg
Contains thermodynamic models developed by D.B. Robinson &
Associates for their proprietary amine plant simulator, AMSIM.
You can use this property package for amine plant simulations
with HYSYS.
ASME Steam
Restricted to a single component, namely H2O. Uses the ASME
1967 Steam Tables.
NBS Steam
Restricted to a single component, namely H2O. Utilizes the NBS
1984 Steam Tables.
MBWR
This is a modified version of the original Benedict/Webb/Rubin
equation. This 32-term equation of state model is applicable for
only a specific set of components and operating conditions.
OLI_Electrolyte
Developed by OLI Systems Inc. and used for predicting the
equilibrium properties of a chemical system including phase and
reactions in a water solution.
Component List Selection
You must also select a Component List to associate with the current
Fluid Package from the Component List Selection drop-down list.
Component Lists are stored outside of the Fluid Package Manager in the
Components Manager and may contain traditional, hypothetical, and
electrolyte components.
It is not recommended for users to attach the Master Component List to
any Fluid Package. If only the master list exists, by default a cloned
version of the Master Component List is created (called Component List
-1). This list is selected initially when a new Fluid Package is created.
HYSYS provides a warning message when you attempt to associate a
Component List containing incompatible and/or not recommended
components, with your property package.
Also, if you switch between property packages, and any components are
incompatible or not recommended for use with the current property
package, a view appears providing further options (see the following
Warning Messages section).
2-12
Fluid Package
2-13
Warning Messages
There are two different warning views that you may encounter while
modifying a Fluid Package. These situations arise when a Component
List is installed into the Fluid Package and you want to select a new
property package. Some components from the selected Component List
may either not be recommended or are incompatible with the new
property package selection.
The first view involves the use of Non-Recommended components. In
HYSYS, you can select components that are not recommended for use
with the current property package. If you try to switch to another
property package for which the components are not recommended, the
following view appears:
Figure 2.5
The objects from the Components Not Recommended for Property
Package view are described below:
Object
Description
Not
Recommended
The non-recommended components are listed in this group.
Desired Prop Pkg
This field initially displays the Property Package for which the
listed components are Not Recommended.
This field is also a drop-down list of all available Property
Packages so you may make an alternate selection without
returning to the Fluid Package property view.
Action
This group box contains two radio buttons:
• Delete Components. This removes incompatible
components from the Fluid Package.
• Keep Components. This keeps the components in the
Fluid Package.
OK
Accepts the Desired Prop Pkg with the appropriate Action.
Cancel
Return to the Prop Pkg tab without making changes.
2-13
2-14
HYSYS Fluid Package Property View
The second dialog involves the use of Incompatible components. If you
try to switch to a property package for which the components are
incompatible, the following view appears:
Figure 2.6
The Objects from the Components Incompatible with Property Package
view are described below:
Object
Description
Incompatible
Components
The incompatible components are listed in this group.
Desired Prop Pkg
This field initially displays the Property Package for which the
listed components are Incompatible.
This field is also a drop-down list of all available Property
Packages so you may make an alternate selection without
returning to the Fluid Package property view.
OK
This button accepts the Desired Prop Pkg with the appropriate
Action (i.e., delete the incompatible components).
Cancel
Press this button to keep the current Property Package
Additional Property Package Options
When you have selected a Property Package, additional information and
options may be displayed on the right side of the Set Up tab. This
information is directly related to the Property Package type selected.
In this section, the additional information displayed with the property
method selection is discussed. The groups that are encountered are
shown below. It should be noted that not all EOS’s or Activity models
include the specifications indicated.
2-14
Fluid Package
Property Packages
Specifications and Options
Equation of States
EOS Enthalpy Method Specification, Peng Robinson
Options, EOS Density and Smooth Liquid Density
Specifications
Activity Models
Activity Model Specifications
Amine Pkg
Amine Options:
• Thermodynamic Models for Aqueous Amine
Solutions
• Vapour Phase Model
OLI_Electrolyte
OLI_Electrolyte Options:
• Initialize and View Electrolytes
• Phase and Solid options
2-15
EOS Enthalpy Method Specification
The Lee-Kesler Plocker (LKP) and Zudkevitch Joffee (ZJ) property
packages both use the Lee-Kesler enthalpy method. You cannot change
the enthalpy method for either of these Equations of State (i.e., Figure
2.7 is not displayed).
Figure 2.7
With any other Equation of State, you have a choice for the enthalpy
method as described below:
Lee-Kesler enthalpies may be
slightly more accurate for
heavy hydrocarbon systems,
but require more computer
resources because a separate
model must be solved.
Enthalpy Method
Description
Equation of State
With this radio button selection, the enthalpy method contained
within the Equation of State is used.
Lee-Kesler
The Lee-Kesler method is used for the calculation of enthalpies.
This option results in a combined Property Package, employing
the appropriate equation of state for vapour-liquid equilibrium
calculations and the Lee-Kesler equation for the calculation of
enthalpies and entropies. This method yields comparable results
to HYSYS' standard equations of state and has identical ranges
of applicability.
2-15
2-16
HYSYS Fluid Package Property View
Peng Robinson Options
The Peng Robinson options are only available when the Peng Robinson
property package is selected. The options are explained in the table
below:
Option
Description
HYSYS
The HysysPR EOS is similar to the PR EOS with several enhancements
to the original PR equation. It extends its range of applicability and better
represents the VLE of complex systems.
Standard
This is the standard Peng Robinson (1976) equation of state, a
modification of the RK equation to better represent the VLE of natural
gas systems accurately.
For more information on property packages, refer to
Section A.3.1 - Equations of State in Appendix A.
EOS Density and Smooth Liquid Density Specifications
The Use EOS Density and Smooth Liquid Density checkboxes affect the
PR, PRSOUR, SRK, and SRKSOUR property packages. In previous
versions to HYSYS 3.0, these property packages used the Costald liquid
density model. This method was only applied when the reduced
temperature (Tr) was less than unity. When the reduced temperature
exceeded unity, it switched to the EOS liquid density. Hence, at Tr=1
there is a sharp change (discontinuity) in the liquid density causing
problems especially in dynamics mode.
For older cases including HYSIM cases, the density smoothing option is
not selected. This means that liquid densities in cases using the
smoothing option may differ from those cases in the past.
Costald typically gives better
liquid densities and smoothing
near Tr = 1 is common.
By default, new cases have the density smoothing option selected and
EOS density not selected, which is the recommended option. By default,
or if the smoothing option is selected, HYSYS interpolates the liquid
densities from Tr=0.95 to Tr=1.0, giving a smooth transition. It should be
noted that the densities differ if the option is not selected.
If both the Use EOS Density and Smooth Liquid Density boxes are not
selected, the behaviour and results are the same as before (previous to
HYSYS 3.0) and can cause problems as discussed earlier.
2-16
Fluid Package
2-17
Activity Model Specifications
The Activity Model Specification group appears for each activity model.
There are three specification items within this group as shown in the
following figure.
Figure 2.8
Activity Models only perform calculations for the liquid phase, thus, you
are required to specify the method to be used for solving the vapour
phase. The first field in the Activity Model Specifications group allows
you to select an appropriate Vapour Model for your fluid package.
The list of vapour phase models are accessed through the drop-down
list and are described below.
Vapour Phase
Models
Description
Ideal
The HYSYS default. It is applied for cases in which you are operating
at low or moderate pressures.
RK
The generalized Redlich Kwong cubic equation of state is based on
reduced temperature and reduced pressure, and is generally
applicable to all gases.
Virial
Enables you to better model the vapour phase fugacities of systems
that display strong vapour phase interactions. Typically this occurs in
systems containing carboxylic acids, or other compounds that have
the tendency to form stable hydrogen bonds in the vapour phase.
PR
Uses the Peng Robinson EOS to model the vapour phase. Use this
option for all situations to which PR is applicable.
SRK
Uses the Soave Redlich Kwong EOS to model the vapour phase. Use
this option for all situations to which SRK is applicable.
The second field in the Activity Model Specifications group is the
UNIFAC Estimation Temp. This temperature is used to estimate
interaction parameters using the UNIFAC method. By default, the
temperature is 25 °C, although better results are achieved if you select a
temperature that is closer to your anticipated operating conditions.
2-17
2-18
HYSYS Fluid Package Property View
The third field in this group is a checkbox for the Poynting Correction.
This checkbox toggles the Poynting correction factor, which by default,
is activated. The correction factor is only available for vapour phase
models. The correction factor uses each component’s molar volume
(liquid phase) in the calculation of the overall compressibility factor.
Amine Options
The following Amine options are available when the Amine pkg is
selected.
Figure 2.9
The Thermodynamic Models for Aqueous Amine Solutions allows you
to select between the Kent-Eisenberg and Li-Mather models. Refer to
the Appendix C.4 - Equilibrium Solubility for detailed information on
each model. The Vapour Phase Model group allows you to select
between Ideal and Non-Ideal models.
OLI_Electrolyte Options
Refer to the HYSYS OLI
Interface Reference Guide
for detailed information on
electrolytes.
If the OLI_Electrolyte property package is selected for the fluid package,
the following electrolyte options appear on the right side of the view.
Figure 2.10
2-18
Fluid Package
2-19
After selecting electrolyte components for a component list from the
database, a electrolyte system is established. The initialize Electrolytes
Environment button is used for the following:
•
•
Generating a group of additional components based on the
selected components and the setting in Phase Option and Solid
Option below.
Generating a corresponding Chemistry model for thermodynamic
calculation.
The phase option includes the vapour, organic, solid, and aqueous
phases. The checkboxes allow you to select the material phases that are
considered during the flash calculation. The vapour, organic and solid
phases, may be included or excluded from calculations. The aqueous
phase must be included in all electrolyte simulations and is not
accessible. By default, the vapour and solid phases are selected with the
organic phase unchecked.
The flexibility of selecting different phase combinations and the
procedure for phase mixing used by the flash calculation is described in
the following table:
Phases Included
Description of the Flash Action
Vapour and Solid
Generates vapour and solid phases when they exist. If an
organic phase appears, it is included in the vapour phase.
Organic and Solid
Generates the organic and solid phase when they exist. If a
vapour phase appears, it is included in the organic phase.
Vapour and Organic
Generates the vapour and organic phase when they exist. If a
solid phase appears, it is included in the aqueous phase.
Vapour only
Generates the vapour phase when it exists. If an organic phase
appears, it will be included in the vapour phase and if a solid
phase appears, it is included in the aqueous phase.
Organic Only
Generates the organic phase when it exists. If a vapour phase
appears, it will be included in the organic phase and if a solid
phase appears, it is included in the aqueous phase.
Solid Only
An electrolyte case with no organic or vapour phase is
impossible and is not be accepted.
2-19
2-20
HYSYS Fluid Package Property View
Refer to Section 1.6.6 Disabling Solid
Components in the HYSYS
OLI Interface Guide for more
information on including and
excluding solids.
Refer to Section 1.6.7 Scaling Tendencies of the
HYSYS OLI Interface Guide
for more information on
scaling tendencies.
The Solid Option group includes two checkboxes and the Selected Solid
button. HYSYS allows you to exclude all solids in your case by selecting
the Exclude All Solids checkbox. It also allows you to exclude solid
components individually when the solid phase is included by disabling
solid components that are not of interest in the simulation. To do this,
you must invoke Initialize Electrolytes Environment first, and then click
the Selected Solid button. When you click the button, you can select any
component that you want to be included or excluded in all of the
Electrolyte streams from the case. When the solid components are
excluded, you have to re-initialize the Electrolytes Environment.
If you select the All Scaling Tendency checkbox, all solids are excluded
from the case, but the Scaling Tendency Index is still calculated in the
flash calculation.
The View Electrolyte Reaction in Trace Window button is activated
when the Electrolytes Environment is initialized. It allows you to view
what reaction(s) are involved in the Thermo flash calculation in the
trace window.
2.4.2 Parameters Tab
The information and options displayed on the Parameters tab is
dependent on the Property Package selection. Some Property Packages
have nothing on the Parameters tab, while others display additional
information required. Those Property Packages which have information
on the Parameters tab are mentioned in this section.
If a value is estimated by HYSYS, it is indicated in red and can be
modified.
2-20
Fluid Package
2-21
GCEOS (Generalized Cubic EOS)
The Generalized Cubic Equation of State (GCEOS) is an alternative to
the standard equation of state property packages. It allows you to define
and customize the cubic equation to your own specifications.
Figure 2.11
Generalized Cubic Equation of State
To gain an understanding of how to specify the GCEOS property
package Parameters tab, you must first consider the general cubic
equation of state form:
a(T)
RT
P = ----------- – -----------------------------------2
2
v – b v + ubv + wb
(2.1)
OR
3
2
Z + C1 Z + C2 Z + C3 = 0
(2.2)
2-21
2-22
HYSYS Fluid Package Property View
where:
C 1 = Bu – B – 1
2
2
C 2 = B w – B u – Bu + A
3
(2.3)
2
C 3 = – ( B w + B w + AB )
Pv
Z = ------RT
(2.4)
a mix P
A = ------------2 2
R T
(2.5)
b mix P
B = -------------RT
a mix =
∑ ∑ xi xj
b mix =
(2.6)
a i ( T )a j ( T ) × MR ij
(2.7)
∑ xi bi
(2.8)
ai ( T ) = ac α
(2.9)
2
3 + ( u – w )ξ
a c =  --------------------------------- + uξ RT c V c
 3 + ( u – 1 )ξ

(2.10)
b i = ξV c
(2.11)
3
2
[ u ( w + u ) – w ]ξ + 3 ( w + u )ξ + 3ξ – 1 = 0
(2.12)
MRij = the mixing rule
To calculate the values of bi and ac, the cubic equation, Equation (2.12),
is solved to find a value for ξ.
2-22
Fluid Package
2-23
The value of ai in Equation (2.9) requires you to use the α term.
0.5
α ( T ) = [ 1 + κ ( 1 – TR ) ]
2
(2.13)
α in turn is made up of the κ term.The parameter κ is a polynomial
equation containing five parameters: κ0, κ1, κ2, κ3, κ4 and κ5. The
parameter κ0 is also represented by a polynomial equation consisting of
4 parameters (A, B, C and D).
κ4
0.5
κ = κ 0 + [ κ 1 + ( κ 2 – κ 3 T R ) ( 1 – T R ) ] × ( 1 + T R ) ( 0.7 – T R ) × T
2
κ 0 = A + Bω + Cω + Dω
κ5
3
(2.14)
(2.15)
The Parameters tab for the GCEOS consists of three group boxes:
•
•
•
GCEOS Pure Component Parameters
GCEOS Parameters
Initialize EOS
2-23
2-24
HYSYS Fluid Package Property View
GCEOS Pure Component Parameters Group
This group allows you to define α by specifying the values of κ0-κ5.
To specify the value of κ0, select the kappa0 radio button and a view
similar to the one shown in Figure 2.12 should appear. The group
consists of a matrix containing 4 parameters of Equation (2.15): A, B, C,
and D for each component selected in the Fluid Package.
Figure 2.12
To specify the remaining kappa parameters (i.e., κ1-κ5), select the
kappa1-5 radio button. A new matrix appears in the GCEOS Pure
Component Parameters group.
Figure 2.13
2-24
Fluid Package
2-25
This matrix allows you to specify the κ values for each component in the
Fluid Package.
Volume Translation
The GCEOS allows for volume translation correction to provide a better
calculation of liquid volume by the cubic equations of state. The
correction is simply a translation along the volume axis, which results
in a better calculation of liquid volume without affecting the VLE
calculations. Mathematically this volume shift is represented as:
n
v˜ = v –
∑ xi ci
(2.16)
i=1
n
b˜ = b –
∑ xi ci
(2.17)
i=1
where:
v˜ = translated volume
b˜ = is the translated cubic equation of state parameter
ci = the pure component translated volume
xi = the mole fraction of component i in the liquid phase.
The resulting equation of state appears as shown in Equations (2.4),
(2.5) and (2.6) with b and v replaced with the translated values ( v˜ and
b˜ ).
2-25
2-26
HYSYS Fluid Package Property View
To specify the value of the pure component correction volume, ci, select
the Vol. Translation radio button. A view similar to the one shown in
Figure 2.14 will appear.
Figure 2.14
HYSYS only estimates the
correction volume constant for
those components whose
cells have no value (i.e., they
contain 0.000). If you specify
one value in the matrix and
click the Estimate button, you
are only estimating those
empty cells.
To estimate a cell containing a
previously entered value,
select the cell, delete the
current value and click the
Estimate button.
The GCEOS Pure Components Parameters group now contains a matrix
containing the volume correction constants for each component
currently selected. The matrix should initially be empty. You may enter
your own values into this matrix or you may click the Estimate button
and have HYSYS estimate values for you. ci is estimated by matching
liquid volume at normal boiling point temperature with that of the
liquid volume obtained from an independent method (COSTALD).
GCEOS Parameters Group
The GCEOS Parameters group allows you to specify the u and w
parameters found in Equations (2.3) to (2.15).
The following table lists the u and w values for some common
equations of state:
2-26
EOS
u
w
van der Waals
0
0
Redlich-Kwong
1
0
Peng-Robinson
2
-1
Fluid Package
2-27
Equation Status Bar
The GCEOS Parameter group also contains the Equation Status Bar. It
tells you the status of the equation definition. There are two possible
messages and are described as follows:
Message
Description
This message appears if poor values are chosen for u and w.
If the values selected for u and w are suitable this message
appears.
Initialize EOS
The Initialize EOS drop-down list allows you to initialize GCEOS
Parameters tab with the default values associated with the selected
Equation of State.
The four options available are as follows:
•
•
•
•
van der Waals Equation
SRK Equation
PR Equation
PRSV Equation
Kabadi Danner
The Kabadi Danner Property Package uses Group Parameters that are
automatically calculated by HYSYS. The values are generated from
Twu’s method.
Figure 2.15
2-27
2-28
HYSYS Fluid Package Property View
Peng-Robinson Stryjek Vera (PRSV)
PRSV uses an empirical factor, Kappa, for fitting pure component
vapour pressures.
Figure 2.16
Zudkevitch Joffee
This Property Package uses a b zero Parameter. HYSYS sets the b zero
parameter of the ZJ equation to be zero.
Figure 2.17
Chien Null
The Chien Null model provides a consistent framework for applying
different activity models on a binary by binary basis. On the Parameters
tab, you can specify the Activity Model to be used for each component
pair, as well as two additional pure component parameters required by
the model.
2-28
Fluid Package
2-29
The two groups on the Parameters tab for the Chien Null property
package are:
•
•
Chien Null Component Parameters
Chien Null Binary Component Parameters
Component Parameters
Values for the Solubility and Molar Volume are displayed for each
library component and estimated for hypotheticals.
Figure 2.18
The Molar Volume parameter is used by the Regular Solution portion of
the Chien Null equation. The Regular Solution is an Activity Model
choice for Binary pair computations (see the following section).
Binary Component Parameters
All of the components in the case, including hypotheticals, are listed in
the matrix. You can view the details for the liquid and vapour phase
calculations by selecting the appropriate radio button:
•
•
Liq Activity Models
Virial Coefficients
Figure 2.19
2-29
2-30
HYSYS Fluid Package Property View
The Property Packages
available in the drop-down list
are:
•
•
•
•
•
•
•
•
None Required
Henry
van Laar
Margules
NRTL
Scatchard
Reg Soln
General
By selecting the Liq Activity Models radio button, you can specify the
Activity Model that HYSYS uses for the calculation of each binary. The
matrix displays the default property package method selected by HYSYS
for each binary pair. The choices are accessed by highlighting the dropdown list in each cell. If Henry’s Law is applicable to a component pair,
HYSYS selects this as the default property method. When Henry’s Law is
selected by HYSYS, you cannot modify the model for the binary pair.
In the previous view, NRTL was selected as the default property package
for all binary pairs. You can use the default selections, or you can set the
property package for each binary pair. Remember that the selected
method appears in both cells representing the binary. HYSYS may filter
the list of options according to the components involved in the binary
pair.
By selecting the Virial Coefficients radio button, you can view and edit
the virial coefficients for each binary. Values are only shown in this table
when the Virial Vapour model is selected on the Set Up tab. You can use
the default values suggested by HYSYS or edit these values. Virial
coefficients for the pure species are shown along the diagonal of the
matrix table, while cross coefficients, which are mixture properties
between components, are those not along the diagonal.
Wilson
The Molar Volume for each library component is displayed, as well as
those values estimated for hypotheticals.
Figure 2.20
2-30
Fluid Package
2-31
Chao Seader & Grayson Streed
The Chao Seader and Grayson Streed models also use a Molar Volume
term. Values for Solubility, Molar Volume, and Acentricity are displayed
for library components. The parameters are estimated for hypotheticals.
Figure 2.21
Antoine
HYSYS uses a six term Antoine expression, with a fixed F term. For
library components, the minimum and maximum temperature and the
coefficients (A through F) are displayed for each component. The values
for Hypothetical components are estimated.
Figure 2.22
2-31
2-32
HYSYS Fluid Package Property View
2.4.3 Binary Coefficients Tab
The Binary Coefficients (Binary Coeffs) tab contains a matrix table
which lists the interaction parameters for each component pair.
Depending on the property method selected, different estimation
methods may be available and a different view may be shown. You have
the option of overwriting any library value.
The cells with unknown interaction parameters contain dashes (---).
When you exit the Basis Manager, unknown interaction parameters are
set to zero.
For all matrices on the Binary Coeffs tab, the horizontal components
across the top of the matrix table represent the "i" component and the
vertical components represent the "j" component.
Generalized Cubic Equation of State Interaction
Parameters
When GCEOS is the selected property package on the Set Up tab, the
Binary Coeffs tab appears as shown below.
Figure 2.23
2-32
Fluid Package
2-33
The GCEOS property package allows you to select mixing methods used
to calculate the equation of state parameter, aij. HYSYS assumes the following general mixing rule:
a ij =
where:
(2.18)
a i a j MR ij
MRij = the mixing rule parameter.
There are seven methods to choose for MRij:
Equation
2
MR ij ( T ) = ( 1 – A ij + B ij T + C ij T )
(2.19)
MR ij ( T ) = ( 1 – A ij + B ij T + C ij ⁄ T )
(2.20)
2
2
MR ij ( T ) = 1 – x i ( 1 – A ij + B ij T + C ij T ) – x j ( 1 – A ij + B ij T + C ij T )
(2.21)
MR ij ( T ) = 1 – x i ( 1 – A ij + B ij T + C ij ⁄ T ) – x j ( 1 – A ij + B ij T + C ij ⁄ T )
(2.22)
( k ij × k ji )
MR ij ( T ) = 1 – --------------------------x i k ij + x j k ji
where: k ij = A ij + B ij T + C ij T
( k ij × k ji )
MR ij ( T ) = 1 – --------------------------x i k ij + x j k ji
where:
(2.23)
2
(2.24)
C ij
k ij = A ij + B ij T + ------T
Wong Sandler Mixing Rule - See the following subsection.
Each mixing rule allows for the specification of three parameters: Aij, Bij
and Cij, except for the Wong Sandler mixing rule which has the Aij and
Bij parameter and also requires you to provide NRTL binary coefficients.
2-33
2-34
HYSYS Fluid Package Property View
The parameters are available through the three radio buttons in the
upper left corner of the tab: Aij, Bij and Cij/NRTL. By selecting a certain
parameter’s radio button you may view the associated parameter matrix
table.
When selecting the Cij/NRTL radio button you are specifying the Cij
parameter unless you are using the Wong Sandler mixing rule. In this
case you are specifying NRTL binary coefficients used to calculate the
Helmholtz energy.
Wong Sandler Mixing Rule
The Wong Sandler1 mixing rule is a density independent mixing rule in
which the equation of state parameters amix and bmix of any cubic
equation of state are determined by simultaneously solving:
•
•
the excess Helmholtz energy at infinite pressure.
the exact quadratic composition dependence of the second virial
coefficient.
To demonstrate this model, consider the relationship between the
second viral coefficient B(T) and the equation of state parameters a and
b:
a
B ( T ) = b – ------RT
(2.25)
Consider the quadratic composition dependence of the second virial
coefficient as:
Bm ( T ) =
∑ ∑ xi xj Bij ( T )
i
(2.26)
j
Substitute B with the relationship in Equation (2.25):
a mix
b mix – ---------- =
RT
-
∑ ∑ xi xj  b – -----RT ij
a
i
2-34
j
(2.27)
Fluid Package
2-35
To satisfy the requirements of Equation (2.27), the relationship for amix
and bmix are:
-
∑ ∑ xi xj  b – -----RT ij
a
(2.28)
i j
b mix = -----------------------------------------------F(x)
1 – ----------RT
with:
a mix = b mix F ( x )
where:
(2.29)
F(x) = is an arbirtrary function
The cross second virial coefficient of Equation (2.8) can be related to
those of pure components by the following relationship:
ai  
aj 
 b – -----i RT- +  b j – -----
RT
a
 b – ------- = ----------------------------------------------------- ( 1 – A – B T )
ij
ij

2
RT ij
(2.30)
The Helmholtz free energy departure function is the difference between
the molar Helmholtz free energy of pure species i and the ideal gas at
constant P and T.
vi


IG
A i ( T, P ) – A i ( T, P ) =  – ∫ P dv


 v=∞

RT
-------
 P


RT 
–  – ∫ ------- dv
v 

 v=∞

(2.31)
2-35
2-36
HYSYS Fluid Package Property View
The expression for Ae is derived using lattice models and therefore
assumes that there are no free sites on the lattice. This assumption can
be approximated to the assumption that there is no free volume. Thus
for the equation of state:
lim v i = b i
P→∞
(2.32)
lim v mix = b mix
P→∞
bmix can be approximated by the following:
-
∑ ∑ xi xj  b – -----RT ij
a
i j
b mix = ----------------------------------------------------------------e
ai
 A ∞ ( x )
1 +  --------------- – ∑ x i  ------------


RT
b


i RT
(2.33)
i
therefore amix is:
ai
e
ai
e
a mix
---------- =
b mix
∑ xi ---b-i – A∞ ( x )
F(x) =
∑ xi ---b-i – A∞ ( x )
(2.34)
i
and F(x) is:
(2.35)
i
e
The Helmholtz free energy, A ∞ ( x ), is calculated using the NRTL model.
You are required to supply the binary coefficient values on the
parameters matrix when the Cij/NRTL radio button is selected. Note
that the α term is equal to 0.3.
2-36
Fluid Package
2-37
Equation of State Interaction Parameter
This information applies to the
following Property Packages:
•
•
•
•
•
Kabadi Danner
Lee-Kesler Plocker
PR
PRSV
Soave Redlich Kwong,
SRK
• Sour PR
• Sour SRK
• Zudkevitch Joffee
The Equation of State Interaction Parameters group is shown below for
a selected EOS property package as displayed on the Binary Coeffs tab
using an EOS, as displayed on the Binary Coeffs tab when an EOS is the
selected property package, is shown below.
Figure 2.24
Note: These two radio buttons only
appear for the PR and SRK based
Equations of State.
This is equivalent to no Kij
The numbers displayed in the table are initially calculated by HYSYS,
but you can modify them. All known binary interaction parameters are
displayed, with unknowns displayed as dashes (---). You have the option
of overwriting any library value.
For all Equation of State parameters (except PRSV), Kij = Kji, so when you
change the value of one of these, both cells of the pair automatically
update with the same value. In many cases, the library interaction
parameters for PRSV do have Kij = Kji, but HYSYS does not force this if
you modify one parameter in a binary pair.
2-37
2-38
HYSYS Fluid Package Property View
If you are using PR or SRK (or one of the Sour options), two radio
buttons are displayed at the bottom of the tab.
Radio Button
Description
Estimate HC-HC/Set
Non HC-HC to 0.0
This radio button is the default selection. HYSYS provides the
estimates for the interaction parameters in the table, setting all
non-hydrocarbon pairs to 0.
Set All to 0.0
When this is selected, HYSYS sets all interaction parameter
values in the table to 0.0.
Activity Model Interaction Parameters
This information applies to the
following property packages:
•
•
•
•
•
•
•
•
Chien Null
Extended NRTL
General NRTL
Margules
NRTL
UNIQUAC
van Laar
Wilson
You may reset the binary
parameters to their original
library values by clicking the
Reset Params button.
The Activity Model Interaction Parameters group, as displayed on the
Binary Coeffs tab when an Activity Model is the selected property
package, is shown in the figure below.
Figure 2.25
The numbering and naming of the radio buttons selections vary
according to the selected Activity Model.
The interaction parameters for each binary pair are displayed; unknown
values will show as dashes (---). You can overwrite any value or use one
of the estimation methods. The estimation methods are described in the
following section.
To display a different coefficient matrix (i.e., Bij), select the appropriate
radio button.
2-38
Fluid Package
2-39
Estimation Methods
Since the Wilson equation
does not handle three phase
systems, the Coeff Estimation
group does not show the
UNIFAC LLE or Immiscible
radio buttons when this
property package is used.
Alphaij = Alphaji, but
When using Activity Models, HYSYS provides three interaction
parameter estimation methods. Select the estimation method by
selecting one of the following radio buttons and then invoke the
estimation by selecting one of the available buttons:
Button
Description
UNIFAC VLE
HYSYS calculates parameters using the UNIFAC VLE model.
UNIFAC LLE
HYSYS calculates all parameters using the UNIFAC LLE model.
Immiscible
The three buttons used for the UNIFAC estimations are replaced by
the following:
• Row in Clm Pair. Use this button to estimate the parameters
such that the row component (j) is immiscible in the column
component (i).
• Clm in Row Pair. Use this button to estimate parameters such
that the column components (j) are immiscible in the row
components (i).
• All in Row. Use this button to estimate parameters such that
both components are mutually immiscible.
Aij ≠ Aji.
UNIFAC estimations are by
default performed at 25 °C,
unless you change this value
on the Set Up tab.
You may reset the binary
parameters to their original
library values by clicking the
Reset Params button.
If you have selected either the UNIFAC VLE or UNIFAC LLE estimation
method, you can apply it in one of the following ways, by selecting the
appropriate button:
Button
Description
Individual Pair
This button is only visible when UNIFAC VLE is selected. It
calculates the parameters for the selected component pair, Aij and
Aji. The existing values in the matrix are overwritten.
Unknowns Only
If you delete the contents of cells or if HYSYS does not provide
defaults values, you can use this option and have HYSYS calculate
the activity parameters for all the unknown pairs.
All Binaries
Recalculates all the binaries in the matrix. If you had changed some
of the original HYSYS values, you can use this to have HYSYS reestimate the entire matrix.
2-39
2-40
HYSYS Fluid Package Property View
2.4.4 Stability Test Tab
The stability test can be thought of as introducing a "droplet" of nucleus
into the fluid. The droplet then either grows into a distinctive phase or is
dissolved in the fluid.
For multi-phase fluids, there exist multiple false calculated solutions. A
false solution exists when convergence occurs for a lower number of
phases than exists in the fluid. For example, with a three-phase fluid,
there is the correct three-phase solution, at least three false two-phase
solutions and multiple false single-phase solutions. A major problem in
converging the flash calculation is arriving at the right solution without
a prior knowledge of the number of equilibrium phases.
The Stability Test allows you to instruct HYSYS on how to perform phase
stability calculations in the Flowsheet. If you encounter situations
where a flash calculation fails or you are suspicious about results, you
can use this option to approach the solution using a different route.
The strategy used in HYSYS is as follows: unless there is strong evidence
for three phases, HYSYS first performs a two-phase flash. The resulting
phases are then tested for their stability.
Figure 2.26
2-40
Fluid Package
2-41
Dynamic Mode Flash Options Group
HYSYS enables you to modify the flash calculation methods to be used.
There are three setting options available:
Flash Option
Description
Try IOFlash first
This activates an alternative optimized Inside-Out flash algorithm
that may provide a significant speed improvement in many cases. It
is aimed at dynamics mode, but operates in steady state mode as
well. The flash can handle rigorous three phase calculations using
the Stability Test Parameters settings, although it is not tested as
well as the default flash algorithms and does not work with all
property packages. If you experience problems that are flash
related, try selecting or deselecting the option. For maximum speed
in two phase systems, you can also set the Maximum Phases
Allowed for the fluid package to two in the Stability Test Parameters
group, or set the Method to none to disable the test.
If the IOFlash fails, HYSYS will
immediately go to method
selected in the Secant Flash
Options group.
The remaining options are for the dynamic mode secant flash options.
COMThermo is not optimized
for dynamics mode and may
result in performance issues if
used in dynamics mode.
Flash3
This is the default secant flash algorithm used in dynamics mode. It
is fast, but does not perform rigorous phase stability tests based on
the option set in the Stability Test Parameters group. Hence, it may
not always detect a second liquid phase when it is present.
Multi Phase
This is a secant flash algorithm that performs phase stability testing
according to the settings in the Stability Test Parameters group.
This option is typically slower than the flash3 option. It can be used
when multiple liquid phases are important or in rare cases where
using the flash3 option results in instabilities due to the second
liquid phase not being detected consistently.
Use Multi Phase
Estimates
The checkbox becomes available when you select Multi Phase as
the Secant Flash Option. If the case consist of three phases,
estimates are passed to the flash which speeds up some flashes.
If the IOFlash option is selected, the Pressure Flow Solver group on the
Dynamics page of the Preferences options allows the flash to be solved
simultaneously with heat transfer equations. The option can result in a
further significant speed increase, but should only be used if the case is
stable using IO.
If a dynamics case has more than one liquid phase (or if a single liquid
phase is aqueous or a hydrocarbon), it is recommended that you use the
Phase Sorting Method for the fluid package on the Section 2.4.5 - Phase
Order Tab. By default, phases are sorted on density and phase types. If
the phase type changes, instabilities may result. The Phase Sorting
Methods allow you to clearly define the order in which phases should be
defined so that they are consistent.
2-41
2-42
HYSYS Fluid Package Property View
Stability Test Parameters Group
You can specify the maximum number of phases allowed (2 or 3) in the
Maximum Phases Allowed input cell. If this value is set to 2, the stability
test quits after 2-phase flashes. Occasionally, you may still get 3 phases,
as the flash may attempt to start directly with the 3-phase flash.
The Stability scheme used is that proposed by Michelson. In the Method
group, you can select the method for performing the stability test
calculations by selecting one of the following radio buttons:
Radio Button
Description
None
No stability test is performed.
Low
Uses a default set of Phases/Components to Initiate the Stability Test.
This method includes the Deleted phases (if they exist), the Wilson’s
Equation initial guess and the Water component (if it exists) in the fluid.
Medium
In addition to the options used for the Low method, this method also
includes the Average of Existing phase, the Ideal Gas phase and the
heaviest and lightest components in the fluid.
All
All available Phases and Components are used to initiate the test.
User
Allows you to activate any combination of checkboxes in the Phase(s)
to Initiate Test and Comp(s) to Initiate Test groups. If you make
changes when a default Method radio button (i.e., Low, Medium) is
selected, the method will be changed to User automatically.
HYSIM Flash
This is the flash method used in HYSIM. If this choice is selected,
HYSYS will use the same flash routines as in HYSIM and no stability
test will be performed. This option allows comparison of results
between HYSIM and HYSYS. This stability option is not recommended
for dynamics mode. Use the default flash3 option with the stability
parameter set to none.
Phases to Initiate Test
There are four choices listed within the Phase(s) to Initiate Test group.
These checkboxes are activated according to the radio button selection
in the Method group. If you change the status of any option, the radio
button in the Method group is automatically set to User.
2-42
Checkboxes
Description
Deleted
If a phase is removed during the 2-phase flash, a droplet of the
deleted fluid is re-introduced.
Average of
Existing
The existing equilibrium fluids are mixed in equal portions; a droplet
of that fluid is introduced.
Fluid Package
One limitation with the stability
test is the fact that it relies on
the property package chosen
rather than physical reality. At
best, it is as accurate as the
property package. For
instance, the NRTL package is
known to be ill-behaved in the
sense that it could actually
predict numerous equilibrium
phases that do not exist in
reality. Thus, turning on all
initial guesses for NRTL may
not be a good idea.
Checkboxes
Description
Ideal Gas
A small amount of ideal gas is introduced.
Wilson’s
Equation
A hypothetical fluid is created using the Wilson’s K-value and is used
to initiate the stability test.
2-43
If any one of these initiating nuclei (initial guesses) forms a distinctive
phase, the existing fluid is unstable and this nucleus provides the initial
guess for the three-phase flash. If none of these initial guesses shows
additional phases, it can only be said that the fluid is likely to be stable.
Temperature Limits
The temperature limits are intended to be used in dynamics mode and
are set to stop the flash when the limits are attained. If the limits are
reached, then dynamics will extrapolate thereafter. The limits avoid
potential problems with some property packages at low temperatures
and during severe process upsets where you would get numerical errors
and heat exchanger convergence problems.
Components to Initiate Test
When a "droplet" of nucleus is introduced into the fluid, the droplet
either grows into a distinctive phase or is dissolved in the fluid. Another
obvious choice for the droplet composition is one of the existing pure
components. For example, if the fluid contains hexane, methanol and
water, one could try introducing a droplet of hexane, a droplet of
methanol or a droplet of water. The choices for the pure component
"droplets" are listed in the Comp(s) to Initiate Test group.
2-43
2-44
HYSYS Fluid Package Property View
2.4.5 Phase Order Tab
Refer to Section 3.1 Material Stream Property
View of the Operations
Guide for more information on
stream properties.
The Phase order feature is intended for dynamics. HYSYS dynamics
always uses three phases for streams and fluids in the stream property
view. For each unit operation, dynamics also assumes that the same
material is in the same phase slot for all of the connected streams. The
order of the first phase is always vapour and the second phase is liquid.
The third phase may be aqueous or it can be a second liquid phase.
By default, HYSYS sorts these phases based on their Type (liquid or
aqueous) and Phase Density. However, subtle changes to the stream
properties may change the order. Stream properties displayed as a liquid
phase in one instance may be displayed as an aqueous phase in another.
For example, inside a tray section the composition of a phase may
change so that instead of being aqueous it is a liquid phase. The phase
moves to a different slot in the fluid. This can cause disturbances in
dynamics mode. The Phase Sorting Method includes two options and is
shown below.
Figure 2.27
2-44
Fluid Package
2-45
Use Phase Type and Density
This option changes the order
of phases in steady state as
well. Although in steady state
many of the calculations
depend on the phase type and
not the order, and hence
should not have any significant
impact.
This option can cause instabilities in dynamics. In practice if small
spikes are identified and an examination of the flowsheet reveals that
some material appears in different phase slots in different parts of the
flowsheet (where the spikes originate) than the user specified option is
recommended.
Use User Specified Primary Components
The Use User Specified Primary Components option displays the Select
Primary Phase Components group that allows you to specify which
components should be in phase slot 1 and which components should be
in phase slot 2. These checks are used to determine the phase order
wherever the fluid package in question is used.
If there is only one non-vapour phase present and the mole fractions of
the primary component adds up to more than the specified threshold, it
is considered to belong in phase slot 1 and of type “liquid 1”. Otherwise
the ratio of primary component for the two choices is examined.
Changing this option does not
resolve the case or immediately
update the affected streams.
The changes occur while the
integrator is running, which
minimizes disturbances.
This option is recommended when:
•
•
•
a simulation is performed and it has more than one liquid phase.
the densities of the two liquid phases may be close.
one or more phases is close to being labelled either aqueous or
liquid.
2-45
2-46
HYSYS Fluid Package Property View
2.4.6 Reactions Tab
See Chapter 5 - Reactions
for more information.
Within the Basis Environment, all reactions are defined through the
Reaction Manager (Reactions tab of the Simulation Basis Manager). On
the Rxns tab of the Fluid Package property view, you are limited to
attaching/detaching reaction sets.
Figure 2.28
The objects for the Rxns tab within the Fluid Package property view are
described below.
2-46
Object
Description
Current
Reactions Sets
This lists all the currently loaded reactions set in this Fluid Package.
Associated
Reactions
There are two Associated Reactions list boxes. Both boxes displays
all the reactions associated with the respective selected Reaction
Set.
Add Set
This button attaches the highlighted Available Reaction Set to the
Fluid Package and displays it in the Current Reactions Sets group.
Remove
This button removes the highlighted Current Reaction Set from the
Fluid Package.
Available
Reactions Sets
This list-box displays all the Available Reactions Sets in the case.
Simultaneous
Basis Mgr
Click this button to access the Reaction Manager.
Fluid Package
2-47
2.4.7 Tabular Tab
The Tabular Package can regress the experimental data for select
thermophysical properties such that a fit is obtained for a chosen
mathematical expression. The Tabular Package is utilized in
conjunction with one of the HYSYS property methods. Your targeted
properties are then calculated as replacements for whatever procedure
the associated property method would have used.
Although the Tabular Package can be used for calculating every
property for all components in the case, it is best used for matching a
specific aspect of your process. A typical example would be in the
calculation of viscosities for chemical systems, where the Tabular
Package will often provide better results than the Activity Models.
HYSYS contains a default
library containing data for over
1,000 components.
Tabular Package calculations are based on mathematical expressions
that represent the pure component property as a function of
temperature. The values of the property for each component at the
process temperature are then combined, using the stream composition
and mixing rule that you specify.
The Tabular provides access to a comprehensive regression package.
This allows you to supply experimental data for your components and
have HYSYS regress the data to a selected expression. Essentially, an
unlimited number of expressions are available to represent your
property data. There are 32 basic equation shapes, 32 Y term shapes, 29
X term shapes, as well as Y and X power functions. The Tabular provides
plotting capabilities to examine how well the selected expression
predicts the property. You are not restricted to the use of a single
expression for each property. Each component can be represented
using the best expression.
Whenever experimental data
is supplied, it is retained in the
memory by HYSYS and
stored in the case.
You may not need to supply experimental data to use the Tabular. If you
have access to a mathematical representation for a component/
property pair, you can simply select the correct equation shape and
supply the coefficients directly. Further, HYSYS provides a data base for
nearly 1,000 library components, so you can use this information
directly within the Tabular without supplying any data whatsoever.
2-47
2-48
HYSYS Fluid Package Property View
The PPDS database is an
optional tabular feature.
Contact your Hyprotech
representative for further
information.
In addition, HYSYS can directly access the information in the PPDS
database for use in the Tabular. This database is similar to that provided
with HYSYS in that the properties for the components are represented
using a mathematical expression.
The Heat of Mixing property can be applied in one of two manners. For
Activity Models that do not have Heat of Mixing calculations built in, this
allows you to supply data or have the coefficients estimated, and have
Heats of Mixing applied throughout the flowsheet. Equations of State do
account for Heat of Mixing in their enthalpy calculations, however, in
certain instances predict the value incorrectly. You can use this route to
apply a correction factor to the Equation of State.
In the cases where the Equation of State is predicting too high a value,
implementing a negative Heat of Mixing can correct this.
Requirements for Using the Tabular
There are only two requirements on the usage of the Tabular package.
First, most properties require that all components in the case have their
property value calculated by the Tabular. Second, enthalpy calculations
require that the Tabular be used for both the liquid and vapour phase
calculations. Similarly, you may use only one enthalpy type property for
each phase. For example, liquid enthalpy and liquid heat capacity
cannot both be selected. An extension to this occurs when the latent
heat property is selected. When this property is activated, only one
enthalpy type property or one heat capacity property may be selected.
Limits in the Tabular Option
In enthalpy extrapolation, if the upper temperature limit (Tmax) is less
than the critical temperature (Tc) HYSYS Tabular option continues to
extrapolate the data based on the original curve up to the critical point.
At this point, an internal extrapolation method is used to calculate the
liquid enthalpy. Due to the internal extrapolation method, there may be
a huge discontinuity and poor extrapolation results from Tmax to Tc. The
poor calculated values cause problem with the PH flash calculation.
2-48
Fluid Package
2-49
There are two methods to avoid this problem:
•
•
Increase the Tmax value of the original enthalpy curve. However,
as mentioned above the curve itself does not extend above Tmax
very well and produces poor results. You will have to be
responsible for changing the curve shape to extrapolate in a
better manner.
User the Enthalpy Model Tr Limit option. This option allows you to
control the starting temperature at which the extrapolation
method is implemented. So instead of Tc, the extrapolation will
start at a certain Tr (the default value is 0, which tells HYSYS to
use the default method) typically 0.7 to 0.99.
Extrapolating accurate/adequate data is important, especially for
enthalpy values approaching the critical point, as the values can change
in odd manner and may require special extrapolation.
If you are not using PPDS mixing rules (PPDS extrapolation methods)
HYSYS supplies a very simple extrapolation based on constant Cp
calculated from the original tabular enthalpy curve. This method keeps
everything monotonically increasing through the critical point and into
the dense phase.
2-49
2-50
HYSYS Fluid Package Property View
Using the Tabular Package
When using the Tabular package a general sequence of steps is shown
below:
1.
Enable the Options, Configuration and Notes pages by checking the
Enable Tabular Properties checkbox.
Figure 2.29
To view all pages under the
options, use the “+” to expand
the tree.
2.
Select the Basis for Tabular Enthalpy by clicking the appropriate
radio button on the Configuration page.
3.
Select the checkboxes for the desired target properties from the All
Properties, Physical and Thermodynamic pages in the Options tree
configuration. The All Properties page is shown below.
Figure 2.30
2-50
Fluid Package
2-51
As properties are added, the Information tree also becomes expandible.
This may be done by clicking on the “+” that appears in front of the
Information label. Expanding this tree displays all of the active target
properties selected on the Options pages. If the Heat of Mixing property
is activated on the All Properties or Thermodynamics page, a new
expandible tree for Heat of Mixing appears in the Tabular Package
group.
4.
If you have the PPDS database, click the checkbox for the database.
5.
Once a target property is selected on one of the three Options pages,
you may select the Mixing Basis by using the drop-down list. The
Parameter value may also be changed on this page.
6.
To view the existing library information, you must first select the
desired page from the expandible Information tree. Click the
desired property from the tree list.
Figure 2.31
2-51
2-52
HYSYS Fluid Package Property View
7.
To plot the existing library information, click the Cmp Plots button.
Click a component using the drop-down list in the Curve Selection
group to change the components being plotted. The variables,
Enthalpy vs. Temperature are plotted from the Variables group and
shown in the figure below.
Figure 2.32
8.
Return to the Information page of the property by closing the plot
view. To view the PropCurve property view for a selected
component, highlight a value in the column of the desired
component and click the Cmp Prop Detail button.
Figure 2.33
9.
2-52
Set the Equation Form and supply data. You can view this same
format of data for library components.
Fluid Package
2-53
The Tabular tab of the fluid package property view contains two pages
and three trees of information, which are displayed at different times
depending on the options selected. These pages are:
•
•
•
•
•
Configuration Page
Options Tree
Information Tree
Heat of Mixing Tree (appears only when Heat of Mixing is
activated in the Options)
Notes
Configuration Page
The configuration page consists of two groups, the Global Tabular
Calculation Options, and the Basis for Tab. Enthalpy (ideal gas).
Figure 2.34
2-53
2-54
HYSYS Fluid Package Property View
Global Tabular Calculation Behaviour Group
The Global Tabular Calculation Behaviour Group contains two
checkbox options:
Activating the Enable Tabular
Properties checkbox will make
the Options tree, Information
tree, and Notes page
available.
Checkbox
Description
Enable
Calculation of
Active
Properties
If this is activated, all the selected Active Properties are calculated
via the Tabular Package. If this checkbox is not activated, all
properties are calculated by the Property Package. This provides a
master switch to enable/disable the Tabular Package while retaining
the Active Property selections.
Enable Tabular
Properties
Toggles the Tabular Properties on or off. If the checkbox is toggled
off, no other pages are available and none of the previously inputted
data is stored.
Please note the difference between the Enable Calculation of Active
Properties and the Enable Tabular Properties checkboxes. The Enable
Calculation of Active Properties checkbox toggles between the
properties regressed from the data supplied on the Tabular tab and the
default values calculated by the Property Package. While deactivating
the checkbox returns to the default Property Package values, the tab
retains all inputted data for the active property selections.
The Enable Tabular Properties checkbox makes the other pages active
for specification. Deactivating this checkbox purges the tab of any
tabular property data it might have previously contained.
Basis for Tabular Enthalpies
This group becomes active after the Enable Tabular Properties checkbox
is clicked. It allows you to select between the enthalpy basis for tabular
calculations:
•
•
2-54
H = 0 K, ideal vapour (HYSIM basis)
H = Heat of formation at 25 °C, ideal vapour
Fluid Package
2-55
Options Tree Configuration
You can target a property through the three pages available in the
Options tree. To expand the tree, click the “+” in front of the Options
label in the Tabular Package group. This allows the All Properties,
Physical, and Thermodynamics pages to be visible. Each one of these
pages consists of a five column matrix table.
Figure 2.35
Property Type
The All Properties page consists of seventeen properties which include
both the Physical and Thermodynamic properties. These properties
have then been subdivided into two groups and displayed again on
either the Physical or Thermodynamics page. These properties are listed
in the table below, along with the subgroup that they belong to:
•
•
•
•
•
•
•
•
•
•
K-value (V/L1)[Thermodynamic]
K-value (V/L2)[Thermodynamic]
K-value (L1/L2)[Thermodynamic]
Enthalpy(L)[Thermodynamic]
Enthalpy(V)[Thermodynamic]
Latent Heat[Thermodynamic]
Heat Capacity(L)[Thermodynamic]
Heat Capacity(V)[Thermodynamic]
Heat of Mixing[Thermodynamic]
Viscosity (L)[Physical]
2-55
2-56
HYSYS Fluid Package Property View
•
•
•
•
•
•
•
Viscosity (V)[Physical]
Thermal Cond (L))[Physical]
Thermal Cond (V))[Physical]
Surface Tension[Physical]
Density (L)[Physical]
Entropy(L)[Thermodynamic]
Entropy(V)[Thermodynamic]
Use HYSYS/Use PPDS
The PPDS database is an
optional tabular feature.
Contact your Hyprotech
representative for further
information.
The checkboxes in the Use HYSYS and Use PPDS columns allow you to
select between the Hyprotech and the PPDS libraries. Depending on the
property type selected, the PPDS library may not be available. When the
PPDS library is available, the checkbox changes from light grey to white.
Composition Basis
The Composition Basis allows you to select the Basis (mole, mass, or liq
volume) on which the mixing rule is applied. When you select a property
type the Composition Basis becomes active for that property. The
available options can be accessed from the drop-down list within the
cell of each property selected.
The default mixing rule which is applied when calculating the overall
property is shown in the following form:
Property mix =
∑ xi Propertyi
f
1
--f
(2.36)
i
Mixing Parameter
The last column in the matrix table is the Mixing Parameter. This allows
you to specify the coefficient (f) to use for the mixing rule calculations.
Notice that the default value is 1.00. The value that HYSYS uses as the
default is dependent on the property selected. For instance, if you select
Liquid Viscosity as the property type, HYSYS uses 0.33 as the default for
the Mixing Parameter.
2-56
Fluid Package
2-57
If you are using the PPDS database, you can modify the mixing rule
parameters for any property with the exception of the vapour viscosity
and vapour thermal conductivity. The parameters for these properties
are set internally to the appropriate PPDS mixing rule.
Information Tree Configuration
It is important to note that the
Heat of Mixing property does
not create a page in the
Information tree. Instead it will
create a unique tree in the
Tabular Package group.
After properties are activated on one of the three pages in the Options
tree, the property appears in the Information tree. This tree may be
expanded by clicking the “+” in front of the Information label in the
Tabular Package group.
Figure 2.36
See Supplying Tabular Data
for further information on the
PropCurve view.
A component may be targeted by clicking in any cell in the component’s
column. For example, if Propane was the component of interest, click in
any cell in the third column. Once the component is targeted, select the
Cmp Prop Detail button to access the PropCurve view. Most of the
information contained in the PropCurve view is displayed on the
Information pages and can also be changed there.
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2-58
HYSYS Fluid Package Property View
Cmp Plots Button
The Cmp Plot button accesses the plot of Temperature vs. the selected
Property Type. The Variables group shows the property used for the X
and Y axis (Enthalpy in this case).
Figure 2.37
Object inspect the plot area to
access the Graph Control
view. Refer to Section 10.4 Graph Control of the User
Guide for more information.
HYSYS can only plot four curves at a time. The Curve Selection group
lists the components which are plotted on the graph. The default is to
plot the first four components in the component list. You can replace
the default components in the Curve Selection group with other
components by using the drop-down list in each cell.
Select the component you want to add to the Curve Selection group. The
new component replaces the previously selected component in the
Curve Selection group, and HYSYS redraws the graph, displaying the
data of the new component.
HYSYS uses the current expressions to plot the graphs, either from the
HYSYS library or your supplied regressed data.
2-58
Fluid Package
2-59
Heat of Mixing Tree
When the Heat of Mixing property is activated on either the All
Properties or the Thermodynamic page in the Options tree, a new tree
gets added to the root of the tree in the Tabular Properties group. This
tree may be expanded by pressing the “+” in front of the Heat of Mixing
label in the tree. The pages in the tree correspond to the components in
the fluid package.
Figure 2.38
Heat of Mixing Page
This page is only visible when Heat of Mixing is selected on the All
Properties or Thermodynamic pages. It consists of the following objects:
Object
Description
UNIFAC VLE
HYSYS uses the UNIFAC VLE estimation method to calculate the
binary coefficients. This overwrites any existing coefficients.
UNIFAC LLE
Same as UNIFAC VLE, except the LLE estimation methods are
used.
Temperature
The reference temperature at which the UNIFAC parameters are
calculated.
2-59
2-60
HYSYS Fluid Package Property View
Composition Pages
The Composition pages in the Heat of Mixing tree are very similar to the
pages contained in the Information tree. Click the View Details button
to access a modified PropCurve view.
Figure 2.39
See Supplying Tabular Data
for further information on the
PropCurve view.
The only difference is that there is no Coeff tab. Most of the information
contained in the PropCurve view is displayed on the Information pages,
where it can be modified.
Notes Page
Any comments regarding the tabular data or the simulation in general
may be displayed here.
2-60
Fluid Package
2-61
Supplying Tabular Data
When you have specified the flowsheet properties for which you want to
use the Tabular Package, you can change the data HYSYS uses in
calculating the properties. HYSYS contains a data file with regressed
coefficients and the associated equation shape, for most components.
If Heat of Mixing is used, you
can access the Prop Curve by
selecting the component and
then click the View Details
button. Although it should be
noted that this view does not
include the Coeffs tab.
To illustrate the method of supplying data, use Methane as a
component and Liquid Enthalpy as the Property. From the Enthalpy (L)
Tabular Package group, select the Methane cell as the component and
click the Cmp. Prop. Detail button. The Variables tab of the PropCurve
view is displayed as shown below:
Figure 2.40
The PropCurve property view contains the following tabs:
Tab
Description
Variables
Specify the equation shapes and power functions for the property.
Coeff
Displays the current coefficients for the selected equation.
Table
Current tabular data for the property (library or user supplied).
Plots
Plots of the property using the tabular data and the regressed
equation.
Notes
User supplied descriptive notes for the regression.
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2-62
HYSYS Fluid Package Property View
Variables Tab
The Variables tab is the first tab of the PropCurve property view. It
contains four groups, X-Variable, Y-Variable, Q-Variable, and Equation
Form. The Variables tab is shown in the previous figure.
X-Variable Group
This group contains information relating to the X-Variable and is
described below.
2-62
Cells
Description
X
Since all properties are measured versus Temperature, this cell
always shows Temperature when using the Tabular Package.
Unit
Displays the units for the temperature values. You cannot change
the units here. The HYSYS internal units for Temperature, K, are
always used.
Shape
This is the shape of the X variable. The choices for the X Shape can
be accessed using the drop-down list in the cell. There are 29
available shapes. Use the scroll bar to move through the list. In this
case, the shape selected is Xvar:x. This means that the X variables
in the equation are equal to X, which represents temperature. If
LogX:log10(x) is selected as the X Shape, then the X variables in
the equation are replaced by log10(x).
Shape Norm
This is a numerical value used in some of the X Shapes. In the dropdown list for X Shape, notice that the second choice is Xreduced:x/
norm. The x/norm term, where norm = 190.70, replaces the X
variable in the equation. You can change the numerical value for
Norm in the cell.
Exponent
Allows you to apply a power term to the X term, for example, X0.5.
Eqn Minimum
Defines the minimum boundary for the X variable. When a flowsheet
calculation for the property is outside the range, HYSYS uses an
internal method for extrapolation of the curve. This method is
dependent on the Property being used. See the Equation Form
section.
Eqn Maximum
Defines the maximum boundary for the X variable. When a
flowsheet calculation for the property is outside the range, HYSYS
uses an internal method for extrapolation of the curve. This method
is dependent on the Property being used. See the Equation Form
section.
Fluid Package
2-63
Y-Variable Group
This group contains all information relating to the Y-Variable.
Cells
Description
Y
This is the property chosen for Tabular calculations.
Unit
Displays the units for the Y variable. You cannot change the units here,
it must be done through the Basis Manager (Preferences option).
Shape
This is the shape of the Y variable. The choices for the Y Shape are
available using the drop-down list within the cell. There are 32 shapes
selected. Use the scroll bar to move through the list. In this case, the
shape chosen is Yvar:y. This means that the Y variables in the equation
are equal to Y, which represents enthalpy. If LogY:log10(y) is chosen as
the Y Shape, then the Y variables in the equation are replaced by
log10(y).
Shape Norm
This is a numerical value used in some of the Y Shapes. In the dropdown list for Y Shape, notice that the second choice is Yreduced:y/
norm. The Y variable in the equation is replaced by the y/norm value.
This numerical value can be changed within the cell.
Exponent
Allows you to apply a power term to the Y term, for example, Y0.5.
Q-Variable Group
This group contains all information relating to the Q Variable. This
Variable is used in some of the X and Y Variable equations.
Cell
Description
Q
Represents the Q variable which is always Pressure.
Unit
Displays the units for the Q Variable, which are always the default
internal units of pressure, kPa.
Default
This is the default numerical value given to the Q Variable which can
be modified within the cell.
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2-64
HYSYS Fluid Package Property View
Coefficients Group
This group is only visible in the Heat of Mixing page when it is an active
property.
Figure 2.41
The Coefficients group contains the coefficient values either obtained
from the HYSYS database, or regressed from data supplied in the Table
tab.
Equation Form
Depending on which property you have selected, HYSYS selects a
default Equation Shape. You have the option of using this equation or
an alternative one. You can select a different equation from the dropdown list associated with this cell. This list contains 33 available
equations to choose from.
Figure 2.42
2-64
Fluid Package
Some equation shapes only
allow you to supply
coefficients directly. You are
informed if the equation shape
cannot have tabular data
regressed to it.
2-65
When HYSYS cannot regress the data to produce equation coefficients
for the selected equation shape, the message Non-Regressable appears
on the right of the drop-down list. You can still use the equation shape,
but you have to manually input the coefficients.
Figure 2.43
Coeff Tab
This tab displays the current coefficients for the specified equation.
Notice that this view also contains the Equation Form group, allowing
you to change the equation from this tab.
Figure 2.44
The X, Y, and Q variables and
their units are displayed for
reference only. They can not
be modified.
The Coefficients group contains the coefficient values either obtained
from the HYSYS database, or regressed from data supplied in the Table
tab.
The checkboxes supplied next to each coefficient value allow you to
instruct HYSYS not to regress certain coefficients, they will remain at the
fixed value (default or user supplied) during regression.
2-65
2-66
HYSYS Fluid Package Property View
Table Tab
You can supply your tabular data before or after selecting the Equation
Shape. To enter data, select the Table tab.
Figure 2.45
If the component is from the HYSYS library, 20 points are generated
between the current Min and Max temperatures. If you need to supply
data, click the Clear Data button. You can also add your data to the
HYSYS default data and have it included in the regression.
Supplying Data
To delete a particular data
point, highlight the data point
and press the DELETE key.
If you are going to supply data, select the unit cell under the X and Y
variable columns and press any key to open the drop-down list. From
the list you can change to the appropriate units for your data.
The procedure for supplying data is as follows:
Coefficients calculated using
the deleted data are still
present on the Coeff tab until
the Regress button is clicked.
2-66
1.
Select the appropriate units for your data.
2.
Clear the existing data with the Clear Data button, or move to the
location that you want to overwrite.
3.
Supply your data.
4.
Supply Net Weight Factors if desired.
Fluid Package
2-67
Q-Column
This column contains the Pressure variable. The presence of this extra
variable helps in providing better regression for the data. As with the X
and Y variables, the units for pressure can be changed to any of the units
available in the drop-down list.
Wt Factor
You can apply weighting to individual data points. When the regression
is performed, the points with higher weighting factors are treated
preferentially, ensuring the best fit through that region.
Regressing the Data
After you have provided the data, you need to update the equation
coefficients. Click the Regress button to have HYSYS regress your data,
generating the coefficients based on the current shapes. If you then
change any of the equation shapes, the data you supplied is regressed
again. You can re-enter the regression package and select a new shape
to have your data regressed.
Data Retention
Whenever experimental data is supplied, it is retained by HYSYS in
memory and is stored in the case. At a later date, you can come back into
the Tabular Package and modify data for the Property, and HYSYS
regresses the data once again.
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2-68
HYSYS Fluid Package Property View
Plot Tab
Use the Plot button on the
Tabular tab to display up to
four component curves on the
same graph.
To examine how the current equations and coefficients represent the
property, select the Plots tab to view the plot.
Figure 2.46
Only the selected component (in this case Methane) is displayed. The
plot contains two curves, one plotted with the regressed equation and
the other with the Table values. If the Tabular values supplied on the
Table tab are in different units, they are still plotted here using the
HYSYS internal units. This provides a means for gauging the accuracy of
the regression. In this example, the two curves overlap each other, such
that it appears to only show one curve.
Besides displaying the component curve, this view also displays the
number of points used in determining the tabular equation (in this case
20). As well, the x-Axis group displays the Min (91.7) and Max (169) xvalues on the curve.
You can change the Min and Max x-axis values and have HYSYS extend
the curve appropriately. Place the cursor in the Min cell and type in a
new value. For example, type 70. This replaces 91.7, and HYSYS extends
the curve to include this value. Similarly, you can change the Max value,
and have HYSYS extend the curve to include this new value. Type 180 to
replace the Max value of 169.00.
2-68
Fluid Package
2-69
The new curve is shown below.
Figure 2.47
Notes Page
To review all notes within the
fluid package, refer to
Section 7.20 - Notes
Manager of the User Guide.
The Notes page is used for supplying a description to associate with the
Tabular Data just entered.
When you have finished providing all necessary data, close the
PropCurve view and return to the Tabular tab of the Fluid Package
property view. You can now continue to supply data for the other
components, if you want. The properties that you have specified to be
calculated with the Tabular package carry through into the Flowsheet.
2.4.8 Notes Tab
The Notes tab allows you to provide documentation that is stored with
the Fluid Package. When you export a Fluid Package, any Notes
associated with it are also exported. When you want to import a Fluid
Package at a later date, the Notes tab allows you to view information
about the Fluid Package.
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2-70
COMThermo Property View
2.5 COMThermo Property View
The Fluid Package COMThermo property view can be accessed by
selecting the COMThermo checkbox in the Advanced Thermodynamics
group. COMThermo consists of eight tabs and is based on the
COMThermo thermodynamics framework. These tabs include
information pertaining to the particular fluid package selected for the
case. When you create a new fluid package and select the COMThermo
radio button the Set Up view appears as shown below.
Figure 2.48
Select a flash calculation method
here. The buttons below are used to
setup the extended custom property
package and extended flash.
Select the Vapor or
Liquid Model
Phase using the
radio buttons.
Information on Property and calculation
Methods depending on the Model
selected. Use the drop-down list to
select alternative calculation methods.
Select a property
model for the
vapor and liquid
phase.
Additional
Information on the
Model selected.
Select a
Component List
here. It is not
recommended to
use the Master
Component List.
Removes the Fluid
Package from the
case. You must confirm
that you want to delete
the Fluid Package.
2-70
The property packages
You can input a name
Select the button to edit
selected for the vapor
for the Fluid Package in
properties at the fluid
and liquid phases are
this cell.
package level.
shown in this status
bar.
Fluid Package
2-71
2.5.1 Set Up Tab
The Set Up tab contains the Model Selection, Model Phase, Model
Options, Extended Setup, Advanced Thermodynamics and Component
List Selection groups for the Fluid Package property view in
COMThermo. After a Model is selected, Properties and Method options
are displayed in the Model Options group. The properties and methods
that are displayed are dependent on the selected Model.
The following sections provide an overview of the various models, as
well as details on the various groups that appear on the Set Up tab.
Model Selection
To create or add property
packages and properties,
refer to the COMThermo
online help in the
development kit.
In the Model Selection group, you have access to the list of default
property models that are available in HYSYS-COMThermo. The
availability of the models depends on the Vapour or Liquid Model Phase
selected for your system. Using the radio buttons, the models are
filtered for vapor and liquid models. A model for the vapor and liquid
phase is required and displayed in the Property Pkg status bar.
Object
Description
Vapor Phase
The Vapor Phase contains a list of Equations of State* used to
model the vapor phase in the Model Selection Group.
Liquid Phase
The Liquid Phase contains a list of the various Equations of
State*, Activity Models*, and semi-empirical methods (Chao
Seader & Grayson Streed) to characterize the liquid phase of a
chemical system.
* Described in the following sections.
For detailed information on COMThermo Models that are available in
HYSYS, refer to Chapter 3 - Thermodynamic Calculation Models in the
COMThermo Reference Guide.
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2-72
COMThermo Property View
Equations of State
Equations of state are used to model the behaviour of single, two, and
three phase systems. For oil, gas and petrochemical applications, the
Peng Robinson Equation of State is generally the recommended
property model. It rigorously solves most single phase, two phase and
three-phase systems with a high degree of efficiency and reliability.
Hyprotech’s enhancements to this equation of state (HysysPR), enable it
to be accurate for a variety of systems over a wide range of conditions.
The equation of state methods and their specific applications are
described below:
EOS
Description
Available for
Ideal Gas
PV=nRT can be used to model the Vapor Phase but
is only suggested for ideal systems under moderate
conditions.
Vapor Phase
only
PR
This model is ideal for VLE calculations as well as
calculating liquid densities for hydrocarbon
systems. However, in situations where highly nonideal systems are encountered, the use of Activity
models is recommended.
Vapor and
Liquid Phase
HysysPR
The HysysPR EOS is similar to the PR EOS with
several enhancements to the original PR equation.
It extends the range of applicability and better
represents the VLE of complex systems.
Vapor and
Liquid Phase
PRSV
This is a two-fold modification of the PR equation of
state that extends the application of the original PR
method for moderately non-ideal systems. It
provides a better pure component vapor pressure
prediction as well as a more flexible mixing rule
than Peng robinson.
Vapor and
Liquid Phase
In many cases it provides comparable results to
PR, but its range of application is significantly more
limited. This method is not as reliable for non-ideal
systems.
Vapor and
Liquid Phase
Braun K10
This model is strictly applicable to heavy
hydrocarbon systems at low pressures. The model
employs the Braun convergence pressure method,
where, given the normal boiling point of a
component, the K-value is calculated at system
temperature and 10 psia (68.95 kPa).
Vapor and
Liquid Phase
KD
Kabadi Danner
This model is a modification of the original SRK
equation of state, enhanced to improve the vaporliquid-liquid equilibrium calculations for waterhydrocarbon systems, particularly in dilute regions.
Vapor and
Liquid Phase
Lee-KeslerPlocker
This model is the most accurate general method for
non-polar substances and mixtures.
Vapor and
Liquid Phase
Peng-Robinson
Peng-Robinson
Stryjek-Vera
SRK
Soave-RedlichKwong
2-72
Fluid Package
2-73
EOS
Description
Available for
Redlich-Kwong
The Redlich-Kwong equation generally provides
results similar to Peng-Robinson. Several
enhancements are made to the PR as described
above which make it the preferred equation of state.
Vapor Phase
only
Sour PengRobinson
Combines the PR equation of state and Wilson’s
API-Sour Model for handling sour water systems.
Vapor and
Liquid Phase
Virial
This model enables you to better model vapor
phase fugacities of systems displaying strong vapor
phase interactions. Typically this occurs in systems
containing carboxylic acids, or compounds that
have the tendency to form stable hydrogen bonds in
the vapor phase. In these cases, the fugacity
coefficient shows large deviations from ideality,
even at low or moderate pressures.
Vapor only
ZudkevitchJoffee
This is a modification of the Redlich Kwong
equation of state, which reproduces the pure
component vapor pressures as predicted by the
Antoine vapor pressure equation. This model is
enhanced for better prediction of vapor-liquid
equilibrium for hydrocarbon systems, and systems
containing Hydrogen.
Vapor and
Liquid Phase
See Chapter 3 - Thermodynamic Calculation Models in the
COMThermo Reference Guide for more detailed information on the
available Equations of State.
Activity Models
Although Equation of State models have proven to be reliable in
predicting the properties of most hydrocarbon based fluids over a wide
range of operating conditions, their application is limited to primarily
non-polar or slightly polar components. Non-ideal systems at low to
moderate pressure are best modeled using Activity Models. Activity
models only perform calculations for the liquid phase. This requires you
to specify a calculation method for the modeling of the vapor phase.
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2-74
COMThermo Property View
Refer to Chapter 3 Thermodynamic Calculation
Models in the COMThermo
Reference Guide for more
detailed information on the
available Activity models.
The following Activity Models are available for modeling the liquid
phase of a system:
Activity Model
Description
Ideal Solution
Assumes the volume change due to mixing is zero. This model is
more commonly used for solutions comprised of molecules not
too different in size and of the same chemical nature.
Regular Solution
This model eliminates the excess entropy when a solution is
mixed at constant temperature and volume. The model is
recommended for non-polar components in which the molecules
do not differ greatly in size. By the attraction of intermolecular
forces, the excess Gibbs energy may be determined.
NRTL
This is an extension of the Wilson equation. It uses statistical
mechanics and the liquid cell theory to represent the liquid
structure. It is capable of representing VLE, LLE, and VLLE
phase behaviour.
General NRTL
This variation of the NRTL model uses five parameters and is
more flexible then the NRTL model. The following equation
format is used for the equation parameters: τ and α:
B ij C ij
τ ij = A ij + ------ + ------2- + F ij T + G ij ln T
T
T
α ij = α1 ij + α2 ij T
Apply this model to systems:
• with a wide boiling point range between components.
• where you require simultaneous solution of VLE and LLE,
and there exists a wide boiling point or concentration range
between components.
2-74
UNIQUAC
Uses statistical mechanics and the quasi-chemical theory of
Guggenheim to represent the liquid structure. The equation is
capable of representing LLE, VLE, and VLLE with accuracy
comparable to the NRTL equation, but without the need for a
non-randomness factor.
Wilson
First activity coefficient equation to use the local composition
model to derive the Gibbs Excess energy expression. It offers a
thermodynamically consistent approach to predicting multicomponent behaviour from regressed binary equilibrium data.
However the Wilson model cannot be used for systems with two
liquid phases.
Chien-Null
Provides consistent framework for applying existing Activity
Models on a binary by binary basis. It allows you to select the
best Activity Model for each pair in your case.
Margules
This was the first Gibbs excess energy representation
developed. The equation does not have any theoretical basis,
but is useful for quick estimates and data interpolation.
NRTL
This is an extension of the Wilson equation. It uses statistical
mechanics and the liquid cell theory to represent the liquid
structure. It is capable of representing VLE, LLE and VLLE
phase behaviour.
Fluid Package
Activity Model
Description
Van Laar
This equation fits many systems quite well, particularly for LLE
component distributions. It can be used for systems that exhibit
positive or negative deviations from Raoult’s Law; however, it
cannot predict maxima or minima in the activity coefficient.
Therefore it generally performs poorly for systems with
halogenated hydrocarbons and alcohols.
UNIFAC VLE/LLE
Both UNIFAC VLE and UNIFAC LLE use the solution of atomic
groups model in which existing phase equilibrium data for
individual atomic groups is used to predict the phase equilibria of
system of groups for which there is no data. The group data is
stored in specially developed interaction parameter matrices for
both VLE and LLE property packages.
2-75
Vapor Pressure Models
Vapor pressure K-value models may be used for ideal mixtures at low
pressures. Ideal mixtures include hydrocarbon systems and mixtures
such as ketones and alcohols, where the liquid phase behaviour is
approximately ideal. The models may also be used as a first
approximation for non-ideal systems.
Vapor Pressure
Models
Description
Antoine
This model is applicable for low pressure systems that behave
ideally.
Braun K10
This model is strictly applicable to heavy hydrocarbon systems at
low pressures. The model employs the Braun convergence
pressure method, where, given the normal boiling point of a
component, the K-value is calculated at system temperature and
10 psia (68.95 kPa).
Esso Tabular
This model is strictly applicable to hydrocarbon systems at low
pressures. The model employs a modification of the MaxwellBonnel vapor pressure model.
Chao Seader & Grayson Streed Models
The Chao Seader and Grayson Streed methods are older, semi-empirical
methods. The Grayson Streed correlation is an extension of the Chao
Seader method with special emphasis on hydrogen. Only the
equilibrium data produced by these correlations is used by HYSYS. The
Lee-Kesler method is used for liquid and vapor enthalpies and
entropies.
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COMThermo Property View
Model
Description
Chao Seader
Use this method for heavy hydrocarbons, where the pressure is
less than 10342 kPa (1500 psia), and temperatures range
between -17.78 and 260 °C (0-500 °F).
Grayson Streed
Recommended for simulating heavy hydrocarbon systems with a
high hydrogen content.
Extended Property Package & Extended Flash
The Extended Property Package model allows the user to incorporate
existing external property packages with minimum modifications to
them. You may setup a number of different property packages using
extended methods, which perform different thermodynamic
calculations, handle different databases for pure compound properties
and/or interaction parameters.
The COMThermo online help
is located in the COMThermo
DK (development kit). You
need to setup the COMThermo
DK from the installation disk.
To set up an Extended
Property Package for
calculations, you must select
the same extended package
for both the vapor and liquid
phases.
2-76
Unlike default COMThermo methods, which are stateless, Extended
Property Packages can keep and carry state information. State
information refers to data such as pure compound and mixture
information. In the implementation of an Extended Property Package,
the calls between different property calculation routines can be made
directly without a need to use COM interfaces. You can mix and match
Extended Property methods with COMThermo default property
calculation methods. This can be set up in the XML model file. Refer to
Extended Property Packages and Flash section in the COMThermo
Programmers Guide for detailed information on how to add extended
flash and extended property packages.
To set up an Extended Property Package two XML model files are
required, one for vapor phase and one for liquid phase. Both XML model
files must contain the same package name. When selecting an extended
package for calculations, the same extended package must be selected
for both vapor and liquid phase.
Fluid Package
2-77
The Extended PropPkg Setup button is accessed by selecting the
appropriate extended package for both the vapor and liquid model
phases. The Extended PropPkg view is shown below for an example
package with ExtPkg as the name of the XML model file.
Figure 2.49
FIF
The Extended Property Package Setup includes a description of the
package and the setup files. The Add button allows you to browse Setup
files for the Extended Property package. The On View button allows you
to see and configure the associated views of your selected extended
method.
The Extended Flash model provides the user with the capability to use
custom flash calculation methods. COMThermo also allows the user to
mix and match different flash methods. For example, the user can
implement a PV (pressure-vapor fraction) flash in an Extended Flash
package and use the existing COMThermo PT flash (pressuretemperature). The flash option can be setup through the Flash Family,
which is located in the Model and Flash XML section of the
COMThermo online help.
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COMThermo Property View
A Extended Flash also requires a flash XML model file to setup the flash
family name. The Extended Flash Setup button is accessed by selecting
the appropriate XML model filename. The Extended Flash Setup view is
shown below for an example flash with ExtendedFlash as the name of
the XML model file.
Figure 2.50
Extended Property Package and Extended Flash can be used together or
separately.
Advanced Thermodynamics
The Advanced Thermodynamics group allows you to model the fluid
package based on the COMThermo framework.
Figure 2.51
2-78
Fluid Package
The imported/exported
COMThermo Property
package can be used in
HYSYS, DISTIL, and
COMThermo Workbench.
The Advanced Thermodynamics group contains the following buttons:
•
•
•
Refer to the Thermodynamics
Workbench Manual of the
Conceptual Engineering
Suite for more information on
COMThermo Workbench.
2-79
Import. Allows you to import an existing COMThermo property
package.
Export. Allows you to export a COMThermo based property
package.
Regression. Allows you to export the fluid package directly into
COMThermo Workbench where the fluid package can be
manipulated by a broad selection of estimation methods and data
regression. Once the regression is complete in the COMThermo
Workbench, the regressed fluid package can be imported back to
HYSYS.
You must have the Conceptual Engineering Suite installed with
COMThermo Workbench licensing in order to apply the Regression
feature in HYSYS.
When you click the Regression button the following view appears:
Figure 2.52
The regressed fluid package
is saved with *.ctf extension
along with two default tag
files, cc.XML, and pm.XML.
You must have all three files
saved in the same directory
to access the regressed fluid
package.
Regression
Description
Start Regression
This button is similar to exporting a fluid package. It allows
you to select a file to be opened up in COMThermo
Workbench for regression analysis.
Load Regression
This button is similar to importing a fluid package. A menu of
existing packages appear, allowing you to retrieve information
from a previously regressed package.
Writing Fluid Package
A status indicator to indicate that a new fluid package is being
generated.
Starting COMThermo
Workbench
A status indicator to indicate that COMThermo Workbench is
starting after the fluid package is generated.
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COMThermo Property View
Component List Selection
You must select a Component List to associate with the current Fluid
Package from the Component List Selection drop-down list.
Component Lists are stored outside of the Fluid Package Manager in the
Components Manager and may contain library, hypothetical, and
electrolyte components. To view the Component List View, click on the
View button.
It is not recommended for users to attach the Master Component List to
any Fluid Package. If only the master list exists, by default a cloned
version of the Master Component List is created (called Component List
-1). This list is selected initially when a new Fluid Package is created.
Model Options
When you have selected a Model, additional property and option
methods are displayed on the right side of the Set Up tab in the Model
Options group. This information is directly related to the Model and
phase selected.
A model must be selected for
both the vapor and liquid
phases.
The Model options group shows each property and what calculation
method is used for that property. For example, the Peng-Robinson
Model Options for the vapor phase are shown below:
Figure 2.53
2-80
Fluid Package
2-81
The Enthalpy property uses the Peng-Robinson Enthalpy calculation
method. The method options which are displayed in red have
alternative calculation methods. By placing your cursor on the dropdown list, you have a choice to select the Lee-Kesler calculation method
for Enthalpy.
Figure 2.54
The Entropy and Cp properties may also be altered to use the Lee-Kesler
calculation methods for the Peng-Robinson EOS. If the property method
is altered, it appears in blue. The information in black are default
methods for HYSYS-COMThermo. Methods are added in the XML file
and then can be seen in the method group for the property selected.
Refer to the Wizards & Add-Ins section of the COMThermo online help
located in the COMThermo Development Kit to help in adding new
properties, property packages, and flash.
EOS Enthalpy, Entropy & Cp Method Specification
With most of the Equations of States, you may have two or three
alternative calculation methods for enthalpy, entropy, and Cp. The
property calculation methods that are available include: the EOS
selected, and the Lee-Kesler method.
Lee-Kesler enthalpies may be
slightly more accurate for
heavy hydrocarbon systems,
but require more computer
resources because a separate
model must be solved.
Methods
Description
Equation of State
With this selection, the enthalpy, entropy, and Cp calculation
methods contained within the Equation of State are used.
Lee-Kesler
The Lee-Kesler method may be used for the calculation of
enthalpies, entropies and Cp values. This option results in a
combined Property Model, employing the appropriate equation of
state for vapor-liquid equilibrium calculations and the Lee-Kesler
equation for the calculation of enthalpies and entropies. This
method yields comparable results to HYSYS standard equations
of state and has identical ranges of applicability.
Once the vapor phase is selected, the liquid phase needs to defined.
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COMThermo Property View
Activity Model Specifications
The Activity Models perform calculations for the liquid phase only.
Once a Liquid phase model is selected, the model options group is filled
with property methods. The UNIQUAC activity model options are
shown below.
Figure 2.55
To aid you in adding customized
properties to the model options
group, refer to Wizards & AddIns section of the COMThermo
Reference Guide.
With most of the activity models, you have a choice for the calculation
method for the standard Ln Fugacity Poynting Correction. By default,
the ideal standard Ln Fugacity is set without the Poynting correction
and may be changed using the drop-down list. The Poynting factor uses
each component’s molar volume (liquid phase) in the calculation of the
overall compressibility factor.
2.5.2 Parameters Tab
The information and options displayed on the Parameters tab is
dependent on the selection of the Property Model. Property models
which require additional parameters are displayed here, while others
are not. For example, the Chein-Null activity model requires parameters
to specify alternative models for binary interaction parameters. The
Chien-Null property package is mentioned in this section.
Chien Null
The Chien Null model provides a consistent framework for applying
different activity models on a binary by binary basis. On the Parameters
tab, you can specify alternative activity models to be used for each
component pair.
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Fluid Package
2-83
Binary Component Parameters
To view the Chein-Null activity models table, CN must be selected as the
liquid phase model and the IP Model Name on the binary coefficients
tab. All components in the case, including hypotheticals are listed in the
table as shown below:
Figure 2.56
The Activity Models available
in the drop-down list are:
•
•
•
•
•
•
•
•
None Required
Henry
van Laar
Margules
NRTL
Scatchard
Reg Soln
General
The table displays the default property methods provided by
COMThermo for each binary pair. The methods are accessed by
highlighting a cell and opening the drop-down list. From the list you can
specify an Activity Model that COMThermo uses for the calculation of
each binary. If Henry’s Law is applicable to a component pair,
COMThermo selects this as the default property method. When Henry’s
Law is selected by HYSYS, you cannot modify the model for the binary
pair.
By default, the Henry and NRTL activity models are selected for the
binary pairs in the above view. You may use the default selections, or set
the property package for each binary pair. Remember that the selected
method appears in both cells representing that binary.
COMThermo may filter the list of options according to the components
involved in the binary pair.
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2-84
COMThermo Property View
2.5.3 Binary Coefficients Tab
The Binary Coefficients (Binary Coeffs) tab contains a table which lists
the interaction parameters for each component pair. Depending on the
property method selected, different estimation methods are available
and therefore a different view may be displayed.
All known binary interaction parameters are shown and the unknown
interaction parameters are displayed with dashes (---). When you exit
the Basis Manager, unknown interaction parameters are set to zero. You
have the option of overwriting any library interaction parameter values.
For all tables on the Binary Coeffs tab, the horizontal components
across the top of the table represent the "i" component and the vertical
components represent the "j" component.
Equation of State Interaction Parameter (IP)
This information applies to
the following Property
Models:
•
•
•
•
•
Kabadi Danner
Lee-Kesler Plocker
PR
PRSV
Soave Redlich Kwong,
SRK
• Sour PR
• Virial
• Zudkevitch Joffee
When you select an EOS model using the IP Model Name drop-down
list, the Interaction Parameter model information is displayed on the
Binary Coeffs tab as shown in the figure below.
Figure 2.57
Note: These two radio buttons only
appear for the PR and SRK based
Equations of State.
2-84
This is equivalent to no Kij
Fluid Package
2-85
The view contains a table of cells commonly referred to as the Matrix
Pane displaying binary interaction coefficients. The top of the view
contains the IP Model Name and Coefficients drop-down lists. The
drop-down lists determine which binary interaction coefficients are
shown in the table:
Drop-Down List
Description
IP Model Name
This drop-down list shows all of the binary interaction coefficient
matrices associated with the property package selected. Ordinarily
there is one, two, or three binary interaction coefficient matrices
per property package. Equations of state typically have one matrix,
and activity coefficient models typically have two IP matrices, one
for ordinary condensable components and the other for noncondensible components The selected Model is displayed in the
Matrix Pane.
Coefficients
This drop-down list shows the type of binary interaction
coefficients that are displayed in the Matrix Pane. The naming
convention for each binary interaction coefficient type is A1i,j, A2i,j,
and so on. This resembles the "aij", "bij" form where i and j are the
column and row in the binary interaction coefficient matrix,
respectively.
Reset COM
Parameters
This button resets all binary interaction coefficients in the matrix
pane to the original HYSYS estimated parameters.
The list of options for both the Model Name and Coefficients are
dependent on the property model (EOS and Activity) selected for the
vapor and liquid phase. For example, if you select the Virial EOS as the
vapor model, it appears in the IP Model Name drop-down list. You can
view and/or edit the virial coefficients for each binary. The following IP
model list represents the vapor (Virial) and liquid models (Chien-Null)
chosen for the example.
Values are only shown in the matrix when the Virial Vapor Phase model
is selected on the Set Up tab. You can use the default values suggested
by HYSYS or edit these values. Virial coefficients for the pure species are
shown along the diagonal of the matrix, while cross coefficients, which
are mixture properties between components, are those not along the
diagonal.
Note that Matrix Pane contains a list of the binary interaction
coefficients for all binary component pairs in the Fluid Package. The
naming convention is as follows:
• i = column
• j = row
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2-86
COMThermo Property View
The numbers that appear in the table are initially calculated by HYSYS
and are modifiable. All known binary interaction parameters are
displayed, with unknowns displayed as dashes (---). You have the option
of overwriting any library value.
For all Equation of State parameters (except PRSV), Kij = Kji. If the value
is modified for one of the parameters, both cells of the pair
automatically update with the same value. In many cases, the library
interaction parameters for PRSV do have Kij = Kji, but HYSYS does not
force this if you modify one parameter in a binary pair.
If you are using PR, SRK or the PR Sour EOS, two radio buttons appear
below the Interaction parameters table.
This information applies to the
following liquid property
models:
•
•
•
•
•
•
•
Chien Null
General NRTL
Margules
NRTL
UNIQUAC
van Laar
Wilson
Radio Button
Description
Estimate HC-HC/Set
Non HC-HC to 0.0
This radio button is the default selection. HYSYS provides
the estimates for the interaction parameters in the table,
setting all non-hydrocarbon pairs to 0.
Set All to 0.0
When this is selected, HYSYS sets all interaction parameter
values in the table to 0.0.
Activity Model Interaction Parameters
The IP activity model displayed in the IP Model drop-down list is the
corresponding liquid phase model selected on the Set Up tab. When you
select an Activity Model in the IP Model Name list, the Interaction
Parameter model information is displayed on the Binary Coeffs tab, as
shown in the figure below.
Figure 2.58
2-86
Fluid Package
2-87
The activity models display the appropriate set of Coefficients for each
component pair. For example, Chien-Null allows for 3 sets of
coefficients for each component pair, where (A1i,j = ai,j, A2i,j = bi,j and
A3i,j = ci,j). Refer to the COMThermo Reference Guide for more
information.
Figure 2.59
You may reset the binary
parameters to their original
library values by clicking the
Reset COM Parameters
button.
The interaction parameters for each binary pair are displayed; unknown
values show as dashes (---). You can overwrite any value.
To display a different coefficient matrix pane (i.e., Bij = A2i,j), select the
appropriate coefficient using the drop-down list.
2.5.4 Stability Test Tab
COMThermo is not optimized
for dynamics mode and may
result in performance issues if
used in dynamics mode.
The StabTest tab allows you to control how phase stability and flash
calculations are performed. If you encounter situations where the flash
fails or you are suspicious about the results, you can use this option to
approach the solution using a different scheme.
For multi-phase fluids, there exist multiple false calculated solutions. A
false solution exists when convergence occurs for a lower number of
phases than exists in the fluid. For example, with a three-phase fluid,
there is the correct three-phase solution, at least three false two-phase
solutions and multiple false single-phase solutions. A major problem in
converging the flash calculation is arriving at the right solution without
a prior knowledge of the number of equilibrium phases.
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2-88
COMThermo Property View
HYSYS initially performs a two-phase flash, unless there is strong
evidence for three phases. The resulting phases are then tested for their
stability. The StabTest view is shown in the figure below.
Figure 2.60
Flash Settings
The following options are available in the Flash Settings table:
Flash Settings
Description of Setting
MaximumNo.
Iterations
You can set the maximum number of iterations executed in the
flash calculations. The algorithm terminates after it reaches the
maximum number of iterations.
Absolute
Tolerance
This is the convergence tolerance of the governing flash
equilibrium equations. If the equilibrium equation error is less than
the Absolute Tolerance, the flash algorithm is assumed to have
converged.
Relative
Tolerance
In addition to the above condition, if the change in the error
between iterations is less than the Relative Tolerance, the flash is
assumed to have converged.
Ignore
Composition
This is used to detect convergence to the trivial solution (where
the compositions in the two phases are identical). If the
differences in the compositions of the two phases are all less than
the Trivial Composition Tolerance, the result is assumed to be
trivial.
To avoid discarding azeotropic results, the compressibility (Z)
factors for the two phases are computed and compared in the case
where the two phases involved are modeled using the same
Property Methods (Equation of State Methods).
2-88
Fluid Package
2-89
Stability Test Parameters
The Stability Test Parameters group is described in the following
sections.
Maximum Phases Allowed
You can specify the maximum number of phases allowed. If the
maximum is set to 2, the stability test terminates after a 2-phase flash.
Occasionally, you may still get three phases, as the algorithm may
attempt to start directly with the 3-phase flash.
Note that if the true solution has two phases and the maximum phases
allowed is set to two, there is still no guarantee that the correct solution
is reached. For instance, for binary mixtures around the azeotropic
point, the correct solution may be liquid-liquid equilibrium, but the
algorithm may incorrectly converge to vapor-liquid equilibrium.
The Stability scheme used is proposed by Michelson(1980a). In the
Method group, you can choose the method for performing the stability
test calculations by selecting one of the radio buttons:
Method Radio
Button
Description
None
No stability test is performed.
Low
Uses a default set of Phases/Components to Initiate the Stability
Test. The following methods are used: Deleted Phase, Wilson’s
Equation and Component Initiation (Water). Only the water
component (if it is part of your Fluid Package) is "introduced".
Medium
In addition to those methods used for the Low method, the
Average of Existing and Ideal Gas methods are also included. As
well, the heaviest and the lightest components in the fluid are
"introduced" using the Component Initiation method.
All
All Phase Initiation methods are utilized, and all components are
introduced using the Component Initiation method.
2-89
2-90
COMThermo Property View
Secant Method Flash Setting
The Secant Method Flash Setting group is shown below.
Figure 2.61
The settings that are available for the Secant Method Flash are shown in
the following table.
Temperature &
Pressure Settings
Description
Default
The default or initial value.
low_bound
The lower or minimum bound for the secant method search.
up_bound
The upper or maximum bound for the secant method search.
maxInc
The maximum increment or initial step size for the secant
temperature search. The logarithm of pressure is used as the
primary variable for the pressure search, thus an initial pressure
multiplier is used as the pressure increment.
tolerance
The tolerance during the secant temperature and pressure
search. It is used mainly by the backup flashes.
Phase Mole Fraction Tolerance
The phase fraction tolerance is used whenever a vapor fraction is given
along with a temperature or pressure for the secant method flash.
HYSYS guesses a temperature or pressure depending on which variable
is required and predicts a new vapor fraction. The calculation
terminates when the vapor fraction is within the tolerance range and the
flash is converged.
2-90
Fluid Package
2-91
Enthalpy Tolerance
Different combinations may be used to flash. If the enthalpy is given,
HYSYS guesses a temperature or pressure depending on which one is
required and predicts a new enthalpy until the flash is converged within
the tolerance specified.
Entropy Tolerance
Different combinations may be used to flash. If the entropy is given,
HYSYS guesses a temperature or pressure depending on which one is
required and predicts a new entropy until the flash is converged within
the tolerance specified.
2.5.5 Reactions Tab
The COMThermo Rxns tab is the same as the traditional HYSYS
property view. See Section 2.4.6 - Reactions Tab.
2.5.6 Notes Tab
See traditional HYSYS thermodynamics Section 2.4.8 - Notes Tab.
2.6 References
1
Wong, D. S. H., Sandler, S. I., “A Theoretically Correct Mixing Rule for Cubic
Equations of State”, A.I.Ch.E. Journal, 38, No. 5, p.671 (1992)
2-91
2-92
2-92
References
Hypotheticals
3-1
3 Hypotheticals
3.1 Introduction......................................................................................3
3.2 Hypo Manager ..................................................................................4
3.3 Adding a Hypothetical - Example...................................................5
3.3.1 Creating the Ethanol Hypo .......................................................5
3.3.2 Hypo/Library Component Comparison ...................................10
3.4 Creating a Hypo Group .................................................................11
3.4.1 Hypo Group View ...................................................................12
3.4.2 Supplying Basic Information...................................................15
3.4.3 UNIFAC Structure...................................................................20
3.5 Hypothetical Component Property View .....................................23
3.5.1
3.5.2
3.5.3
3.5.4
ID Tab .....................................................................................25
Critical Tab..............................................................................25
Point Tab ................................................................................26
TDep Tab................................................................................29
3.6 Solid Hypotheticals .......................................................................32
3.6.1
3.6.2
3.6.3
3.6.4
3.6.5
ID Tab .....................................................................................32
Props Tab ...............................................................................33
Point Tab ................................................................................34
TDep Tab................................................................................35
PSD Tab .................................................................................36
3.7 Cloning Library Components .......................................................37
3.7.1 Converting a Library Component to a Hypo ...........................38
3-1
Hypotheticals
3-2
3.8 Hypo Controls ................................................................................39
3.8.1 Viewing Groups ......................................................................39
3.8.2 Moving Hypos.........................................................................40
3.9 References .....................................................................................40
3-2
Hypotheticals
3-3
3.1 Introduction
HYSYS allows you to create non-library or Hypothetical components
from the Hypo Manager. Hypothetical components can be pure
components, defined mixtures, undefined mixtures, or solids. You can
also convert/clone HYSYS library components into Hypotheticals,
which allow you to modify the library values.
The Hypo Manager is located on the Hypotheticals tab of the Simulation
Basis Manager. It can also be accessed via the Hypo manager button
from the Components tab under hypothetical components.
A wide selection of estimation methods are provided for the various
Hypo groups (hydrocarbons, alcohols, etc.) to ensure the best
representation of behaviour for the Hypothetical component in the
simulation. In addition, methods are provided for estimating the
interaction binaries between hypotheticals and library components.
You can also use Hypotheticals with the Tabular Package, as well as in
Reactions.
In HYSYS, Hypothetical components exist independent of the Fluid
Package. When a Hypothetical is created, it is placed in a Hypo Group.
From the Hypo Manager, you can create new Hypo Groups and move
Hypothetical components within the Hypo Groups. Hypo Groups can
also be imported and exported, thus making them available to any
simulation case.
Since Hypothetical components are not exclusively associated with a
particular Fluid Package, it is possible for multiple Fluid Packages to
share Hypotheticals. In other words, you only need to create a
Hypothetical once, and it can be used in any Fluid Package throughout
the case.
3-3
3-4
Hypo Manager
3.2 Hypo Manager
By selecting the Hypotheticals tab from the Simulation Basis Manager,
the following view appears:
Figure 3.1
Note that you can Import and
Export Hypothetical groups,
allowing you to use defined
hypotheticals in any future
simulation.
Hypothetical groups and
individual hypothetical
components can be installed
in more than one Fluid
Package.
The left side of the view is the Hypothetical Groups group. This lists all
the Hypothetical groups currently installed in the simulation. The
available commands for this group (accessed using the associated
buttons) are as follows:
Button
Description
View
Accesses the Hypo Group view for the selected group.
Add
Adds a Hypothetical Group to the present case.
Delete
Deletes the selected Hypothetical Group from the case.
Translocate
Searches through all of the hypothetical components in the case
and if there are duplicates HYSYS replaces them and puts all the
duplicates in a separate Hypo group which then can be deleted.
This is intended for use when large cases have had large numbers
of templates/fluid packages imported and there are lots of repeated
hypotheticals in the case.
3-4
Import
Imports a Hypothetical Group from disk.
Export
Exports the selected Hypothetical Group and saves it to a file, so
that it can be retrieved at a later time.
Hypotheticals
3-5
The right side of the view displays the Hypothetical Quick Reference
group. This group includes all Hypotheticals currently installed in the
Basis Environment (Hypo Name column) along with their associated
Hypo Groups (Group Name column). The available buttons within this
group are described below:
Button
Description
View Hypo
Access the property view for the highlighted Hypothetical.
View Group
Access the Hypo Group view for the highlighted Hypothetical.
Move Hypos
Move Hypotheticals from one Hypo Group to another.
Clone Comps
Use a copy of a selected library components as the basis for
defining a Hypothetical.
3.3 Adding a Hypothetical - Example
In this example, a hypothetical Ethanol component is defined, and the
results to the library Ethanol component using the Wilson property
package are compared. The ethanol hypothetical component is defined
as having a boiling point of 78.25 °C and a specific gravity of 0.789.
3.3.1 Creating the Ethanol Hypo
To create a ethanol hypo, follow the steps outlined below:
You must install a Hypothetical
Group before you can install a
Hypo component.
From the Session Preferences
view, select SI as the units for
the case.
1.
Open a new case in HYSYS and select the Hypotheticals tab of the
Simulation Basis Manager.
2.
From the Hypothetical Groups group, click the Add button to create
a new Hypothetical Group. HYSYS automatically names this group
HypoGroup1. You can change the name later, if desired.
3-5
3-6
Adding a Hypothetical - Example
3.
When you add a new Hypothetical Group, HYSYS automatically
opens the Hypo Group view, where you add and define the
Hypothetical component(s) for the group. On this view, enter
HypoAlcohol as the new Group Name.
Figure 3.2
4.
Notice that the HYSYS default in the Component Class list is
Hydrocarbon. For this example, select Alcohol for the Component
Class using the drop-down list.
5.
Now, install a Hypothetical component. From the Individual Hypo
Controls group, click the Add Hypo button. This adds a
Hypothetical component and automatically names it Hypo20000*.
6.
Enter a new name for this component by selecting the Name cell
typing HypoEtoh.
7.
In the NBP cell, enter the normal boiling point of the component as
78.25°C.
8.
The specific gravity for the hypothetical component is 0.789. In the
Liq Density cell, enter 0.789 and select the SG_H2O60api units. A
liquid density of 787.41 kg/m3 is calculated by HYSYS.
Figure 3.3
3-6
Hypotheticals
9.
3-7
Although HYSYS could estimate the unknown properties for
HypoEtoh with only the NBP and Liquid Density, more accurate
results are obtained if the component structure is supplied. Click the
UNIFAC button to access the UNIFAC Component Builder.
Figure 3.4
10. The chemical formula of ethanol is C2H5OH, and it is comprised of
the groups CH3, CH2, and OH. Highlight CH3 in the Available
UNIFAC Groups list. It is the first selection in the list.
11. Click the Add Group(s) button. Notice that a “1” is displayed under
Sub Group in the UNIFAC Structure group. By default, HYSYS
assigns the value “1” to the How Many cell. The number is valid,
since this is the number of CH3 groups required. The number of
Free Bonds has increased to 1 with the addition of the CH3 Sub
Group.
12. To add the CH2 group, highlight it in the Available UNIFAC Groups
list (it is the second in the list) and click the Add Group(s) button.
Again, only 1 Sub Group is required, so the default is acceptable.
3-7
3-8
Adding a Hypothetical - Example
13. Since the OH group is not immediately visible in the list of Available
UNIFAC Groups, a different approach is taken. In the UNIFAC
Structure input field, type OH at the end of the existing structure
(CH3CH2) and press ENTER.
Figure 3.5
Notice that the Incomplete
status message is replaced
with Complete when there are
0 Free Bonds.
14. Once the UNIFAC Structure is complete, HYSYS calculates the
UNIFAC Base and Critical Properties. Click the Close icon to close
the view and return to the Hypo Group view.
Property Estimation Methods
are explained in Section 3.4.2 Supplying Basic Information.
15. HYSYS can now use the existing information (NBP, Liquid Density
and UNIFAC structure) to estimate the remaining properties for the
Hypothetical component. First, the Estimation Method that HYSYS
uses is examined. Click the Estimation Methods button to access
the Property Estimation view.
Figure 3.6
3-8
Hypotheticals
3-9
16. If you want, you can change the estimation method for any
property. In this example, all properties use the Default Method.
Click the Close icon to return to the Hypo Group view.
17. Click the Estimate Unknown Props button and HYSYS uses the
currently specified methods to estimate the unknown properties for
the component. The molecular weight for the hypothetical is the
same as the molecular weight for ethanol, 46.07, since the UNIFAC
structure is used for the Hypo component.
Figure 3.7
Remember that specified
values are displayed in blue,
and HYSYS estimated values
are displayed in red.
18. You can examine all properties for the Hypo through its property
view. Double-click on the Hypothetical component name,
HypoEtoh, to access the Component property view.
Figure 3.8
For further information regarding
the Property View, refer to
Section 3.5 - Hypothetical
Component Property View.
19. Click the Close icon to return to the Hypo Group view.
20. Click the Close icon and HYSYS returns you to the Hypotheticals tab
of the Simulation Basis Manager. The Ethanol Hypothetical has is
created.
3-9
3-10
Adding a Hypothetical - Example
3.3.2 Hypo/Library Component Comparison
To conclude, compare the ethanol hypothetical to the ethanol library
component. Go to the Simulation Basis Manager:
3-10
1.
On the Fluid Pkgs tab, click the Add button to install the new Fluid
Package.
2.
On the Set Up tab, select Wilson as the Property Package and close
the fluid package view.
3.
Move to the Components tab and add Ethanol to the Selected
Component List by highlighting the Components page in the Add
Component group.
4.
From the Available Hypo Components group, highlight the
HypoEtoh* component and click the Add Hypo button from the
Hypothetical page.
5.
Move to the Binary Coeffs tab in the fluid package property view
and click the Unknowns Only button in the Coeff Estimation group.
6.
Close the Fluid Package property view.
7.
Click the Enter Simulation Environment button to enter the Main
Environment.
8.
In the Workbook, create the stream Pure. Enter a vapour fraction of
0 and a pressure of 1 atm for the stream on the Material Streams tab
of the workbook. Move to the Compositions tab an enter 1 for the
mole fraction of Ethanol, and 0 for HypoEtoh*.
9.
Now create a second stream, Hypo. Enter a vapour fraction of 0 and
a pressure of 1 atm for the stream. The mole fraction of HypoEtoh*
is 1, and that for Ethanol is 0.
Hypotheticals
3-11
When you have specified these two streams, HYSYS calculates the
bubble point temperature for each stream. The Conditions tab of the
property view for each stream is shown below.
Figure 3.9
3.4 Creating a Hypo Group
When defining a hypothetical, there is no set procedure. The following is
a suggested sequence in which you can follow:
1.
Create the Hypo Group. For more information, see Section 3.4.1 Hypo Group View.
2.
Select the Component Class for the Hypo Group. For more
information, see Section 3.4.1 - Hypo Group View.
3.
Set the Estimation Methods for the Group (optional). For more
information, see Section 3.4.2 - Supplying Basic Information.
4.
Install the Hypotheticals.
5.
Supply all information that you have for the Hypo. For more
information, see Section 3.4.2 - Supplying Basic Information.
6.
Supply a UNIFAC structure for the Hypo (optional). For more
information, see Section 3.4.3 - UNIFAC Structure.
7.
Estimate the Properties for the Hypo.
3-11
3-12
Creating a Hypo Group
3.4.1 Hypo Group View
As mentioned in the Hypothetical example, you add a Hypo Group by
clicking the Add button from the Hypotheticals tab of the Simulation
Basis Manager. This opens the Hypo Group view, which contains two
groups, (Hypo Group Controls and Individual Hypo Controls), and a
table of estimated or known property values.
Figure 3.10
Hypo Group Controls
Note that for the Component
Class, there are varying levels
of specificity. For example,
under Alcohol, you can specify
sub-classes of alcohols, such
as Aliphatic, Aromatic, Cyclo
and Poly. Using a stricter
degree of component type
assists HYSYS in choosing
appropriate estimation
methods; however, it forces all
components to be calculated
using the same method. If you
want to mix component
classes (i.e., both Aliphatic
and Aromatic inside the same
Hypo Group), select the more
general Component Class of
Alcohol.
3-12
The Hypo group contains the following options:
Option
Description
Group Name
Displays the current name for the Hypothetical Group. HYSYS
provides a default name, but you can change this to a more
descriptive name. Individual Hypothetical components must reside
inside of a Hypothetical group.
Component
Class
Every component in a Hypo Group must be of a common
Component Class. The options are accessed using the drop-down
list attached to the input cell. There is a wide selection of available
Classes, which allows for better estimation of the component
properties. HYSYS, by default, selects the Component Class to be
Hydrocarbon. Prior to installing any components, select the
Component Class.
Estimation
Methods
Accesses the Property Estimation view, from which you can select
an estimation method for each property. The selected estimation
methods apply to all Hypotheticals in the Hypo Group.
Hypotheticals
Option
Description
Estimate
Unknown
Props
This button estimates the unknown properties for all Hypothetical
components within the Hypo Group, using the methods chosen on
the Property Estimation view. For more information, Section 3.4.2 Supplying Basic Information.
Clone Library
Comps
HYSYS allows you to convert library components into hypothetical
components. For more information, see Section 3.7 - Cloning
Library Components.
Notes
Allows you to supply Notes and Descriptions for the Hypothetical
Group. This is useful when exporting Hypo groups, because when
you import them later, the description appears along with the Hypo
group name.
3-13
Individual Hypo Controls
The Individual Hypo Controls group at the bottom of the Hypo Group
view contains buttons for manipulating the Hypotheticals within the
Hypo Group and two radio buttons for switching between Base
Properties and Vapour Pressure data.
The View, Delete, and
UNIFAC buttons will not be
available unless a hypothetical
is present in the case.
Button
Description
View
Displays the Property View for the highlighted
hypothetical component.
Add Hypo
Automatically adds a new hypothetical component to the
group. HYSYS places the new Hypo in the table, and
names it according to the default naming convention (set
in the Session Preferences).
Add Solid
Automatically adds a new solid hypothetical component to
the group. HYSYS places the new Hypo in the table, and
names it according to the default naming convention (set
in the Session Preferences).
Delete
Deletes the highlighted hypothetical component from the
case. After deleting a Hypo it cannot be recovered.
UNIFAC
Opens the UNIFAC Component Builder, from which you
can provide the UNIFAC Structure for the highlighted
hypothetical component.
The table displayed in the middle section of the Hypo Group view,
displays either the Base Properties or the Vapour Pressure properties,
depending on which radio button is selected. You can add a new Hypo
component in either the Base Properties or Vapour Pressure view.
3-13
3-14
Creating a Hypo Group
Base Properties
These properties are the
same as those shown on the
Critical tab of the Hypo
component property view.
The Base Properties for each Hypothetical are shown on the Hypo
Group view when the Base Properties radio button is selected.
Figure 3.11
Individual Base Properties are
supplied by selecting the
appropriate cell. Use the dropdown list to select the units
within the cell.
3-14
The table lists each Hypothetical along with the following Base
Properties:
Base Property
Description
NBP
Normal boiling point
MW
Molecular weight
Liq Density
Liquid density
Tc
Critical temperature
Pc
Critical pressure
Vc
Critical volume
Acentricity
Acentric factor
Hypotheticals
3-15
Vapour Pressure Properties
The values shown on this view
are also available on the TDep
tab of the individual Hypo
property view.
Use the horizontal scroll bar to
view Coeff E and Coeff F.
The Vapour Pressure table displays the temperature range and Antoine
Coefficients for the hypothetical components. Also shown are the
pressure and temperature units on which the equation is based and the
form of the equation.
Figure 3.12
3.4.2 Supplying Basic Information
Before HYSYS can estimate the properties for a hypothetical, some
information about the Hypo must be provided. For the estimation, you
must supply a minimum amount of information and select the
estimation methods to be used.
3-15
3-16
Creating a Hypo Group
Minimum Information Required
The more information you can
supply, the more accurate the
estimations are.
If the hypothetical component is defined as a hydrocarbon, the
appropriate default correlations can be used to calculate its critical
properties or any other missing information. Its interaction parameters
are also calculated by HYSYS based on the estimated critical properties.
For HYSYS to estimate the component’s critical properties, a minimum
amount of information must be supplied, as shown in the following
table.
Normal Boiling Point
Minimum Required Information
< 700 °F (370 °C)
Boiling Point
> 700 °F (370 °C)
Boiling Point and Liquid Density
Unknown
API & Molecular Weight
Estimation Methods
Prior to installing any Hypotheticals into a Hypo group, examine the
Estimation Methods which HYSYS uses to calculate the unknown
properties for a hypothetical component. You can specify a estimation
method for each property. Click the Estimation Methods button on the
Hypo Group view.
Figure 3.13
The Estimation Methods that you choose for the Hypo Group apply to
all Hypotheticals in that group.
3-16
Hypotheticals
3-17
There are three groups in the Property Estimation view and are
described below:
Group
Description
Property to Set
Methods For
This group lists all the available properties.
From the list, choose the property for which
you want to set the Estimation Method. Use
the scroll bar to move through the list. Initially,
HYSYS sets all the properties to the Default
Method.
Estimation Method
For Selected
Property
This drop-down list displays all the available
estimation methods for the highlighted
property. Depending on the property, the
drop-down list differs. The list shown here is a
partial display of estimation methods for
Critical Temperature.
Variables Affected
by this Estimate
This group lists all the variables that are
affected by the selected estimation method.
The list changes depending on the property
selected. For example, when you select an
estimation method for Critical Temperature,
you are not only affecting the critical
temperature, but also the properties which
use critical temperature in their estimation or
calculation.
View
3-17
3-18
Creating a Hypo Group
The following table individually lists each Property, its Default Method,
its Available Estimation Methods and the Variables Affected by
estimating the Property. It is understood that each property can have Do
Not Estimate selected as its Estimation Method, so this option does not
appear in the Available Methods list.
Property
3-18
Default Method
Available Methods
Variables Affected
Critical
Temperature
• if ρLIQ > 1067 kg/m3 or
NBP > 800 K, Lee-Kesler
is used
• if NBP < 548.16 K and
ρLIQ<850 kg/m3,
Bergman is used
• all other cases, Cavett is
used
Aspen, Bergman, Cavett, Chen
Hu, Eaton Porter, Edmister,
Group Contribution, Lee Kesler,
Mathur, Meissner Redding,
Nokay, Riazi Dauber, Roess,
PennState, Standing, Twu
• Critical Temperature
• Standard Liquid
Density
• COSTALD Variables
• Viscosity Thetas
Critical
Pressure
• if ρLIQ > 1067 kg/m3 or
NBP > 800 K, Lee-Kesler
is used
• if NBP < 548.16 K and
ρLIQ <850 kg/m3,
Bergman is used
• all other cases, Cavett is
used
Aspen, Bergman, Cavett,
Edmister, Group Contribution,
Lee Kesler, Lydersen, Mathur,
PennState, Riazi Daubert,
Rowe, Standing, Twu
• Critical Pressure
• Standard Liquid
Density
• COSTALD Variables
• Viscosity Thetas
Critical Volume
• Pitzer
Group Contribution, Pitzer, Twu
• Critical Volume
• Standard Liquid
Density
• COSTALD Variables
• Viscosity Thetas
Acentricity
• for Hydrocarbon, LeeKesler is used
• all other cases, Pitzer is
used
Bergman, Edmister, Lee Kesler,
Pitzer, Pitzer Curl, Robinson
Peng
• w
• ωGs
• Standard Liquid
Density
• COSTALD Variables
• Viscosity Thetas
Molecular
Weight
• if NBP < 155 °F, Bergman
is used
• all other cases, LeeKesler is used
API, Aspen, Aspen Leastq,
Bergman, Hariu Sage, Katz
Firoozabadi, Katz Nokay, Lee
Kesler, PennState, Riazi
Daubert, Robinson Peng, Twu,
Whitson
• Molecular Weight
Normal Boiling
Point
• Hyprotech proprietary
method
Twu
• Normal Boiling Point
• Viscosity Thetas
Vapour
Pressure
• for Hydrocarbon, LeeKesler is used
• all other cases, Riedel is
used
Gomez Thodos, Lee Kesler
• Antoine Coefficient
• PRSV_kappa
Liquid Density
• Yen-Woods
Bergman, BergmanPNA, Chueh
Prausnitz, Gunn Yamada, Hariu
Sage, Katz Firuzabadi, Lee
Kesler, Twu, Whitson,
Yarborough, Yen Woods
• Standard liquid
Density
• COSTALD Variables
Hypotheticals
Available Methods
3-19
Property
Default Method
Variables Affected
Ideal Gas
Enthalpy
• Cavett
Cavett, Falon Watson, Group
Contribution, Lee Kesler,
Modified Lee Kesler,
• Ideal H Coefficient
Heat of
Formation
• for chemical structure
defined in UNIFAC
groups, Joback is used
• all other cases, this
formula is used:
Group Contribution
• Heat of Formation
• Heat of Combustion
H form ( octane ) ⋅ MW
-------------------------------------------------MW ( octane )
Ideal Gas Gibbs
Energy
• Hyprotech proprietary
method
Group Contribution
• Gibbs Coefficient
Heat of
Vapourization
• Two Reference Fluid
(using benzene and
carbazole)
Chen, Pitzer, Riedel, Two
Reference1, Vetere
• Cavett Variables
Liquid
Viscosity
• for non-Hydorcarbon or
NBP < 270 K Letsou Stiel
is used
• for Hydorcarbon and NBP
< 335 K, NBS viscosity is
used
• all other cases, Twu is
used
Hyprotech Proprietary, Letsou
Stiel
• Viscosity Thetas
Surface
Tension
• Brock Bird
Brock Bird, Gray, Hankin, Sprow
Prausnitz
• Tabular Variables
Radius of
Gyration
• Hyprotech proprietary
method
Default Only
•
•
•
•
•
Critical Temperature
Critical Pressure
Normal Boiling Point
Molecular Weight
Standard Liquid
Density
In defining Hypothetical components, there are some properties for
which you cannot select the estimation method. HYSYS determines the
proper method based on information you have provided. The following
table lists these properties and their respective default methods:
Property
Default Estimation Method
Liquid Enthalpy
• The previously calculated Liquid Heat Capacity is
used.
Vapour Enthalpy
• Liquid Enthalpy + Enthalpy of Vapourization
Chao Seader Molar
Volume
• If Tc > 300 K, Molar Volume from COSTALD @ 25
°C and 1 atm is used
• all other cases, ρLIQ @ 60 °F is used
Chao Seader Acentricity
• component acentric factor is used
Chao Seader Solubility
Parameter
• If Tc > 300K, Watson type Enthalpy of
Vaporization is used
• all other cases, values of 5.0 are used
3-19
3-20
Creating a Hypo Group
Property
Default Estimation Method
Cavett Parameter
• Two Reference Fluid1 method (using benzene and
carbazole)
Dipole Moment
• No estimation method available, sets value equal to
zero.
Enthalpy of Combustion
• No estimation method available, sets value to
<empty>.
COSTALD Characteristic
Volume
• If NBP < 155 °F, Bergman is used
• all other cases, Katz-Firoozabadi is used
Liquid Viscosity
Coefficients A and B
• For non-Hydrocarbon or NBP < 270 K, Letsou Stiel
is used
• for Hydrocarbon and NBP < 335 K, NBS viscosity
is used
• all other cases, Twu is used.
Vapour Viscosity
• Chung
PRSV Kappa1
• Vapour Pressure from Antoine’s Equation
Kfactor1
• Vapour Pressure from Antoine’s Equation
3.4.3 UNIFAC Structure
Most of the estimation methods require a UNIFAC structure for some
aspect of the estimation. It may be that either the property itself, or
some other property that is affected by the estimation procedure
requires the chemical structure.
3-20
Hypotheticals
3-21
The UNIFAC structure is supplied through the UNIFAC Component
Builder. This can either be accessed by clicking the UNIFAC button in
the Hypo Group view, or by clicking the Structure Builder button on the
ID tab of the Hypothetical component property view. Whichever route
is taken, the following view is displayed:
Figure 3.14
The UNIFAC Component Builder view is made up of the following
objects:
Note that this section makes
reference to both the UNIFAC
Structure group (the table of
cells) and the UNIFAC
Structure entry field.
Objects
Description
UNIFAC Structure
Group
Displays the Type and Number of Sub Groups in the UNIFAC
Structure.
Add Group(s)
Adds the currently selected Sub Group from the Available
UNIFAC Groups list box to the UNIFAC Structure group.
Delete Group
Deletes the currently selected Sub Group in the UNIFAC
Structure group.
Free Bonds
Displays the number of free bonds available in the present
UNIFAC Structure. This is 0 when the structure is complete.
Status Bar
This bar is found in the centre of the view. It indicates the
present status of the UNIFAC Structure. You see either
Incomplete in red, Complete in green, or Multi-Molecules in
yellow.
Available UNIFAC
Groups
Contains all the available UNIFAC component sub groups.
UNIFAC Structure
Displays the chemical structure of the molecule you are
building.
field
3-21
3-22
Creating a Hypo Group
Objects
Description
UNIFAC Calculated
Base Properties
Displays properties such as Molecular Weight, the UNQUAC R
parameter, and the UNIQUAC Q parameter for a UNIFAC
Structure with at least 1 sub group.
UNIFAC Calculated
Critical Properties
Displays the critical properties for a UNIFAC Structure with at
least 1 sub group.
The procedure for supplying the UNIFAC structure is to highlight the
Sub Group(s) in the Available UNIFAC Groups column and select the
Add Group(s) button. Additional sub groups can be accessed in the list
by using the Scroll Bar.
As you add sub groups, HYSYS displays the number of Free Bonds
available. This is zero when the UNIFAC structure is complete. When
you have supplied enough groups to satisfy the bond structure, the
status message changes to Complete (with a green background).
As you specify groups, the UNIFAC Calculated Base Properties and
UNIFAC Calculated Critical Properties are automatically updated based
on the new structure.
There are three methods available for adding Sub Groups to the
UNIFAC Structure:
Sub Group
Description
You can highlight more than
one sub group, and add all at
the same time.
Highlighting
the Sub
Group
The list of Available UNIFAC Groups displays all the sub groups. Notice
that CH3 is the first selection in this list. You can use the scroll bars to
move through the list until you find the group you need. When you find
the correct Sub Group, highlight it, and click the Add Group(s) button.
The sub group now appears in the UNIFAC Structure group.
Notice the difference between
the UNIFAC Structure group
(the table of cells) and the
UNIFAC Structure entry field.
Using the
Sub Group
Number
Each sub group has a number associated with it. If you know the
number for the sub group you want to add to the UNIFAC Structure,
move the active location to the Sub Group column of the UNIFAC
Structure group. Enter the number of the Sub Group. HYSYS does not
automatically fill in the number of sub groups. Move the active location
to the How Many column and type in the number of sub groups
required.
Typing in
the UNIFAC
Structure
input field
Notice the UNIFAC Structure input field near the bottom of the view. Any
sub groups already installed are listed here. Place the cursor after the
last group, and type in the group to install. For example, if we want to
add an OH group, type in OH. When you type the sub group in this box,
HYSYS automatically adds it to the UNIFAC Structure group.
3-22
Hypotheticals
3-23
You can add multiples of a Sub Group in the UNIFAC Structure box. Type
the number of Sub Groups and the Sub Group name, separated by a
space. For example, type 3 CH2 to add three CH2 groups to the UNIFAC
structure. NOTE: You cannot add Sub Groups in this way to an existing
UNIFAC structure.
HYSYS automatically calculates Base Properties and Critical Properties
using the currently supplied structure.
3.5 Hypothetical Component
Property View
Hypotheticals, like library components, have their own property view.
Once inside, you can add or modify information, or examine the results
of the estimations.
You can access the property view for the Hypo component from
different views:
View
Method of Accessing Hypo
Simulation Basis
Manager,
Hypotheticals Tab
All the hypothetical components are displayed in the
Hypothetical Quick Reference group. You can either double-click
on the component name, or highlight it and click the View Hypo
button.
Hypo Group
All the hypothetical components in the Hypo Group you have
chosen to view, are displayed. Either double-click on the Hypo
component you want to view, or highlight it and click the View
button.
Simulation Basis
Manager,
Components Tab
After adding a hypothetical to the Selected Component List
group, highlight it and click the View Component button or
object inspect its name and select View.
3-23
3-24
Hypothetical Component Property View
The Hypothetical property view is made up of five tabs and are shown
below. Some of the tabs have radio buttons for switching between the
various properties. When a different radio button is selected, HYSYS
redraws the view with the information appropriate to the item.
Figure 3.15
After you have entered adequate estimation parameters, you can click
the Estimate Unknown Properties button to complete the hypothetical
estimation. The Edit Properties button allows you to edit properties
within the hypocomponent at the component level. The Edit Visc Curve
button allows you to recalculate the viscosity coefficients based on the
temperature and dynamic viscosity data provided by the user. Refer to
Edit Properties in Section 1.2.3 - Manipulating the Selected
Components List for more information.
Throughout the tabs of the property view, information is displayed in
red, blue, and black. Values displayed in red are estimated by HYSYS
and values displayed in blue are user supplied. Black values represent
calculated values or information that you cannot modify (i.e., Family/
Class on the ID tab).
You can supply values directly for any of the component properties, or
overwrite values estimated by HYSYS. If you change a specified value,
all properties previously estimated using that specification are
forgotten. Click the Estimate Unknown Props button to have the
properties recalculated.
3-24
Hypotheticals
3-25
3.5.1 ID Tab
The ID tab is the first tab in the Hypo property view. If it is the first time
you are entering a Property View, HYSYS places you on this tab.
Figure 3.16
If a Structure is
already entered, it
is displayed here.
You can also enter
the Structure
directly into this
cell.
Use this button to
access the
UNIFAC
Component
Builder and
supply the
structure of the
Hypo.
3.5.2 Critical Tab
The Critical tab of the property view displays the base and critical
properties. This is the same information displayed on the Hypo Group
when the Base Properties radio button is selected.
For more information on the
Minimum Information required
for Property Estimation see
Section 3.4.2 - Supplying
Basic Information
You can supply or change the Base Properties on this tab. The views,
shown in Figure 3.17, display the Critical tab before and after the
Estimate Unknown Props button is clicked. Notice that since the
Normal Boiling Point was less that 370 °C, only the Molecular Weight
value was required for this estimation.
3-25
3-26
Hypothetical Component Property View
Figure 3.17
3.5.3 Point Tab
The Point tab displays Additional Point Properties for the hypothetical.
There are two radio buttons on the view, which allow you to toggle
between two tables of information are the:
•
•
Thermodynamic and Physical Properties
Property Package Molecular Properties
Thermodynamic & Physical Properties
This view displays the Thermodynamic and Physical properties for the
Hypo. HYSYS estimates these values, based on the base property data
entered and the selected estimation methods.
3-26
Hypotheticals
3-27
Figure 3.18
Notice that the Heat of Comb field is <empty>. This indicates that
HYSYS cannot estimate this value with the given information. HYSYS
allows you to input a value for this property.
The viscosity coefficients of A and B are first estimated by HYSYS based
on the initial specifications from the Hypo Group view. If you want to
calculate these coefficients, you can override the estimation by clicking
the Edit Visc Curve button. This allows you to enter a set of data points
of temperature versus dynamic viscosity.
Figure 3.19
3-27
3-28
Hypothetical Component Property View
There are three buttons available in the Edit Viscosity Curve view:
Buttons
Descriptions
OK
Allows HYSYS to accept the data to perform
the calculations.
Delete
Clears all the data points in the data table and
closes the view automatically.
Cancel
Cancels the operation and exit the view. The
data points you entered will not be used in the
calculations but these points will be saved in the
data table without being cleared so you can
make modification later.
HYSYS will recalculate the values of the viscosity coefficients based on
the data points you just entered. The values of the viscosity coefficients
A and B will then change from red to black indicating that they are
calculated values.
Property Package Molecular Props
This view displays the Molecular properties for the Hypo. The values
estimated are dependent on the selected estimation method for each
property.
Figure 3.20
Some of the fields in this view are <empty>. This indicates that HYSYS
cannot estimate these values with the information given. However, you
can specify values for these properties.
3-28
Hypotheticals
3-29
3.5.4 TDep Tab
The TDep tab displays Temperature Dependent Properties for the
hypothetical. There are three radio buttons on the view, which allow you
to toggle between the three different displays of information. The views
available are:
•
•
•
Vapour Enthalpy
Gibbs Free Energy
Vapour Pressure
Vapour Enthalpy
The Vapour Enthalpy calculation is performed on a Mass Basis. The
reference point for the equation is an ideal gas at 0 K. The units for Mass
Vapour Enthalpy and Temperature are kJ/kg and degrees Kelvin,
respectively.
Figure 3.21
When required, the Vapour Enthalpy equation is integrated by HYSYS to
calculate entropy. Note that if enthalpy coefficients are entered, a
constant of integration, g, should be supplied along with the other
coefficients. Specify this value in the g coefficient field.
Notice that HYSYS has estimated the Minimum and Maximum
Temperatures.
3-29
3-30
Hypothetical Component Property View
Below the temperature range are values for the Vapour Enthalpy
equation coefficients (from a to g). HYSYS estimates the coefficients, but
you may change any of the values.
Vapour Pressure
The Vapour Pressure is calculated using the Modified Antoine equation.
HYSYS estimates the Minimum and Maximum Temperature values
based on the supplied properties and estimation methods.
Figure 3.22
The units used for Pressure and Temperature are kPa, and degrees
Kelvin, respectively.
The bottom section of this view displays the values for each of the
Antoine equation coefficients (from a to f). HYSYS estimates the
coefficients, however you can modify these values.
3-30
Hypotheticals
3-31
Gibbs Free Energy
The Gibbs Free Energy calculation uses Enthalpy as its property type
and is performed on a Molar Basis. The basis for the equation is ideal gas
at 25 °C. HYSYS estimates the Minimum and Maximum Temperature
values.
Figure 3.23
The units for Molar Enthalpy and Temperature are kJ/kg mole and
degrees Kelvin, respectively.
The bottom section of the view displays the values for each of the Gibbs
Free Energy equation coefficients (from a to c).
HYSYS estimates the Gibbs Free Energy coefficients if you supply the
UNIFAC structure and enter the Ideal Gas Gibbs Free Energy at 25 °C in
the a coefficient cell.
3-31
3-32
Solid Hypotheticals
3.6 Solid Hypotheticals
Solids do not take part in VLE
calculations, but they do have
an effect on heat balance
calculations.
Solid Hypotheticals can be added to any Hypo Group, regardless of the
Group Type. In the Individual Hypo Controls group of the Hypo Group
view, click the Add Solid button.
When you install a solid hypo, you notice that the Base Properties cells
on the Hypo Group view are displayed as <empty>.
3.6.1 ID Tab
To define the Solid Hypo, access its property view by highlighting the
component name on the Hypo Group view and clicking the View
button.
The ID tab of the Solid Component property view is the same as that for
other Hypo components except that the User Props tab is replaced by
the PSD tab. Note that in this case, the Family/Class is Alcohol. The
Class type has no effect on the values calculated for the solid
component.
Figure 3.24
3-32
Hypotheticals
3-33
3.6.2 Props Tab
The Props tab displays the basic properties of the component in two
groups:
•
•
Solid Properties where bulk properties are entered
Coal Analysis where data can be entered on a possible Coal
Analysis
Solid Properties
The minimum information that must be supplied includes the
Molecular Weight and the Density. The appropriate units can also be
specified within the cell as shown below.
Figure 3.25
The other Solid Properties are described below:
Solid Property
Description
Diameter
Particle diameter, if not supplied this defaults to 1 mm when the
remaining properties are estimated.
Sphericity
Value between zero and one, with one being perfectly spherical.
Area/Unit
Volume
Measure of the surface area of the particle as a function of the
particle volume.
3-33
3-34
Solid Hypotheticals
Coal Analysis
You can also provide the results of a Coal Analysis on a percentage basis
for the listed components.
3.6.3 Point Tab
The only information on the Point tab that is relevant to the Solid is the
Heat of Combustion and Heat of Formation.
Figure 3.26
This information is only required if you plan on using a Solid
component as part of a reaction.
3-34
Hypotheticals
3-35
3.6.4 TDep Tab
Note that while other
Hypotheticals use the Ideal
Gas Enthalpy coefficients,
solids use the Specific Heat
Capacity.
Since Solid Hypos do not participate in VLE calculations, their vapour
pressure information is, by default, set to zero. However, since solid
components do affect Heat Balances, the Specific Heat information can
either be estimated by HYSYS, or supplied.
Figure 3.27
3-35
3-36
Solid Hypotheticals
3.6.5 PSD Tab
The PSD tab displays the particle size distribution for solids. It allows
you to specify PSD’s and calculate various mean and modal diameters
for the entered PSD. The PSD tab is shown below.
Figure 3.28
Refer to Section 1.2.3 - Manipulating the Selected Components List and
see UserProp & PSD Tabs for more information on Particle Size
Distribution.
3-36
Hypotheticals
3-37
3.7 Cloning Library Components
By using the Add New Hypo
Group button, you do not have
to return to the Simulation
Basis Manager to create a
Hypo Group.
You can convert HYSYS library components into Hypotheticals through
the Clone Library Comps button on the Hypo Group view. When you
click this button, the Convert Library Comps to Hypothetical Comps
view is displayed. Any of the library components present in the current
Fluid Package can be converted to a Hypothetical.
Figure 3.29
This view is made up of two sections, the Source Components group
and the Hypo Groups.
Object
Description
Component
Lists
Allows you to select the component list that contains the library
component you want to clone.
Available
Library Comps
Selects the component you want to convert into a hypothetical.
Replace ALL
Instances
If you want to replace the library component with the Hypo in every
Fluid Package that contains the library component, activate this
checkbox. If you only want to replace the library components in the
highlighted Fluid Package, do not activate the checkbox.
Hypo Group
Selects the Hypothetical Group in which you want the converted
library component placed.
Hypo
Components
Displays all the hypothetical components present in the selected
hypothetical group. When a library component is converted into a
hypothetical, it is listed here.
3-37
3-38
Cloning Library Components
3.7.1 Converting a Library Component to a Hypo
When converting a library component to a Hypo, follow the procedure
outlined below. Figure 3.29 is used as a reference.
3-38
1.
Select the Component List which contains the target library
component. In this case, Component List - 1 is the selected
component list.
2.
From the Available Library Comps group, select the component to
clone. In this case, 1-Propanol is selected.
3.
Select the Target Hypo Group, where the new Hypo is to be placed.
HypoAlcohol is selected.
4.
Decide if you want to replace all instances of the source component
(1-Propanol) with the new Hypo. Activate the Replace All Instances
checkbox to do this. In Figure 3.29 the checkbox is activated.
5.
To complete the conversion, click the Convert to Hypo(s) button.
6.
The new Hypo appears in the Hypo Components group, and has an
asterisk (1-Propanol*) after its name, signifying that it is a
hypothetical.
7.
Close the view to return to the Hypo Group view.
Hypotheticals
3-39
3.8 Hypo Controls
The manipulation commands for hypotheticals are contained on the
Hypotheticals tab of the Simulation Basis Manager. The Hypo Controls
are the buttons contained within the Hypothetical Quick Reference
group as shown below:
Figure 3.30
3.8.1 Viewing Groups
Notice that the Hypothetical Quick Reference group displays the names
of hypothetical groups and components. The components are listed in
the Hypo Name column and the group to which each component
belongs is listed in the Group Name column.
From the Group Name column, select the Group that you want to view,
and click the View Group button. HYSYS displays the Hypo Group view
for that Hypo Group. All the Hypo components that are part of the
group appear on this view.
3-39
3-40
References
3.8.2 Moving Hypos
By clicking the Add New Hypo
Group button, HYSYS allows
you to add a new Hypo Group
while this view has focus.
When hypothetical components are created in HYSYS, they are created
within a Hypo Group, and become part of the group. After adding a
hypothetical component to a certain group, you may want to move it to
another existing group. You can accomplish this through the Hypo
Controls. From the Hypothetical Quick Reference group, click the Move
Hypo button. This produces the following view:
Figure 3.31
Follow this procedure to move a Hypo to a different Hypo Group:
1.
From the Hypo Components group, select the Hypo that you want
to move.
2.
Select the Target Hypo Group to which the Hypo is being moved.
3.
Click the Switch to Group button, which becomes available when a
selection is made in both the Hypo Components group and Target
Hypo Group.
4.
When you are finished moving groups, close the view and return to
the Hypotheticals tab of the Simulation Basis Manager.
3.9 References
1
3-40
Reid, R.C., Prausnitz, J.M., Poling, B.E., The Properties of Gases & Liquids, 4th
edition, McGraw-Hill, 1987.
HYSYS Oil Manager
4-1
4 HYSYS Oil Manager
4.1 Introduction......................................................................................3
4.2 Oil Characterization.........................................................................4
4.2.1
4.2.2
4.2.3
4.2.4
4.2.5
4.2.6
4.2.7
Laboratory Data........................................................................4
Conventional Distillation Data ..................................................5
Data Reporting Basis ...............................................................7
Physical Property Assay Data ..................................................7
Property Curve Basis ...............................................................7
Common Laboratory Data Corrections.....................................8
Default Correlations..................................................................8
4.3 Petroleum Fluids Characterization Procedure..............................9
4.3.1
4.3.2
4.3.3
4.3.4
4.3.5
4.3.6
Initialization...............................................................................9
Step One - Characterize Assay.............................................. 11
Step Two - Generate Hypocomponents ................................. 11
Step Three - Install Oil............................................................ 11
User Property .........................................................................12
Correlations ............................................................................12
4.4 Oil Characterization View..............................................................13
4.5 Characterizing Assays ..................................................................16
4.5.1
4.5.2
4.5.3
4.5.4
4.5.5
4.5.6
4.5.7
Input Data Tab ........................................................................19
Calculation Defaults Tab.........................................................42
Working Curves Tab ...............................................................46
Plots Tab.................................................................................47
Correlations Tab .....................................................................48
User Curves Tab.....................................................................49
Notes Tab ...............................................................................50
4-1
4-2
HYSYS Oil
4.6 Hypocomponent Generation ........................................................ 51
4.6.1
4.6.2
4.6.3
4.6.4
4.6.5
4.6.6
4.6.7
4.6.8
Data Tab................................................................................. 52
Correlations Tab ..................................................................... 59
Tables Tab .............................................................................. 60
Property Plot Tab ................................................................... 61
Distribution Plot Tab ............................................................... 63
Composite Plot Tab ................................................................ 64
Plot Summary Tab.................................................................. 65
Notes Tab ............................................................................... 66
4.7 User Property................................................................................. 66
4.7.1 User Property Tab .................................................................. 66
4.7.2 User Property View ................................................................ 67
4.8 Correlations & Installation............................................................ 70
4.8.1 Correlation Tab....................................................................... 70
4.8.2 Correlation Set View .............................................................. 71
4.8.3 Install Oil Tab ......................................................................... 75
4.9 TBP Assay - Example.................................................................... 76
4.9.1
4.9.2
4.9.3
4.9.4
4.9.5
Initialization ............................................................................ 78
Step 1 - Input Assay Data ...................................................... 80
Step 2 - Cut Assay into Hypocomponents ............................. 87
Step 3 - Transfer Information to Flowsheet............................ 90
Fluid Package Association ..................................................... 92
4.10 Sulfur Curve - Example ............................................................... 93
4.10.1
4.10.2
4.10.3
4.10.4
4.10.5
Fluid Package ...................................................................... 93
Install a User Property ......................................................... 94
Install the Assay ................................................................... 95
Create the Blend .................................................................. 97
Results ................................................................................. 98
4.11 References ................................................................................. 100
4-2
HYSYS Oil Manager
4-3
4.1 Introduction
Oil Environment Icon
Refer to Chapter 3 Hypotheticals for more
information on hypo
controls.
The Oil Characterization environment can be accessed from the Oil
Manager tab of the Simulation Basis manager or by clicking the Oil
Environment icon on the toolbar. To enter the Oil Characterization
environment, at least one fluid package must exist in the case.
Hypothetical (pseudo) components must be compatible with the
property method being used by the fluid package.
Also on the Oil Manager tab, you can view all flowsheets that exist in the
current case and the fluid package associated with each. All
hypocomponents that are defined within the Oil Characterization
environment are assigned to a Hypo group and installed in an
associated fluid package. Since Light End calculations for an oil require
information from the property method being used by the associated
fluid package, the hypocomponent cannot be shared among different
fluid packages as regular hypothetical components can. However, you
can still use the same hypocomponent in the non-associated fluid
packages by adding them as hypotheticals, via the Add Hypo or Add
Group button on the Selected tab of the Component List property view.
The Oil Characterization environment provides a location where the
characteristics of a petroleum fluid can be represented by using discrete
hypothetical components. Physical, critical, thermodynamic and
transport properties are determined for each hypothetical component
using correlations that you select. The fully defined hypocomponent
can then be installed in a stream and used in any flowsheet.
HYSYS defines the hypocomponent by using assay data which you
provide. The features available for the input of assay data minimize the
time required for data entry. For instance, defined assays can be cloned,
imported and exported. Exported assays can be used in other fluid
packages or in other cases altogether.
4-3
4-4
Oil Characterization
Some of the features exclusive to the oil environment include:
•
•
•
•
•
•
•
Providing laboratory assay data
Cutting a single assay
Blending multiple assays
Assigning a user property to hypocomponents
Selecting correlation sets to determine properties
Installing hypocomponent into a stream
Viewing tables and plots for your input and for the characterized
fluid
4.2 Oil Characterization
The petroleum characterization method in HYSYS converts your
laboratory assay analyses of condensates, crude oils, petroleum cuts,
and coal-tar liquids into a series of discrete hypothetical components.
These petroleum hypocomponents provide the basis for the property
package to predict the remaining thermodynamic and transport
properties necessary for fluid modeling.
HYSYS produces a complete set of physical and critical properties for
the petroleum hypocomponent with a minimal amount of information.
However, the more information you can supply about the fluid, the
more accurate these properties are, and the better HYSYS predicts the
fluid’s actual behaviour.
4.2.1 Laboratory Data
The Watson (UOP) K factor is
an approximate index of
paraffinicity, with high values
corresponding to high
degrees of saturation:
1
--3
( Mean Avg. BP )
K = -----------------------------------------sp gr 60F / 60F
where the mean average
boiling point is in degrees
Rankine.
4-4
Accurate volatility characteristics are vital when representing a
petroleum fluid in your process simulation. HYSYS accepts five standard
laboratory analytical assay procedures:
•
•
•
•
•
True boiling point distillation (TBP)
ASTM D86 and ASTM D1160 distillations (Separately or
Combined)
ASTM D2887 simulated distillation
Equilibrium flash vapourization (EFV)
Chromatographic analysis
HYSYS Oil Manager
4-5
The characterization procedure performs its calculations based on an
internally calculated TBP curve. If you supply an ASTM or EFV
distillation curve, it is converted to a TBP curve using standard methods
described in the API Data Book. If you do not supply any distillation
data, then an average TBP distillation curve is generated for you based
on the overall molecular weight, density, and Watson (UOP) K factor of
your fluid.
4.2.2 Conventional Distillation Data
The five primary types of assay data accepted by the Petroleum
Characterization Procedure in HYSYS are listed here and explained in
the following sections.
•
•
•
•
•
True Boiling Point analysis
ASTM D86 and 1186 Distillations
ASTM D2887
Equilibrium Flash Vaporization
Chromatrographic analysis
True Boiling Point (TBP) Analysis
A TBP analysis is performed using a multi-stage batch fractionation
apparatus operated at relatively high reflux ratios (15 - 100 theoretical
stages with reflux ratios of 5 to 1 or greater). TBP distillations conducted
at either atmospheric or vacuum conditions are accepted by the
characterization procedure.
Note that the initial boiling
point (IBP) of a TBP curve
does not correspond to the
bubble point temperature of
the petroleum fluid at
atmospheric pressure.
The petroleum fluid’s bubble point is a multi-component equilibrium
condition such that there is an incipient vapour phase forming. This
would, in effect, be a single-stage of fractionation as opposed to the
highly refluxed operation of a TBP analysis.
4-5
4-6
Oil Characterization
ASTM D86 and D1160 Distillations
ASTM D86 and ASTM D1160 distillations also employ batch
fractionation apparatus, but they are conducted using non-refluxed
Engler flasks. Two standard ASTM distillations are supported: ASTM
D86, used for light to medium petroleum fluids, and ASTM D1160,
carried out at varying vacuum conditions and used for heavier
petroleum fluids. For ASTM D86 distillation, HYSYS can correct for
barometric pressure or cracking effects.
ASTM D2887
ASTM D2887 is a simulated distillation curve generated from
chromatographic data. The resulting boiling point curve is reported on a
weight percent basis.
Equilibrium Flash Vaporization
An EFV curve is generated by a series of experiments conducted at
constant pressure (1 atm). The results relate the temperature versus
volume percent of liquid distilled, where the total vapour is in
equilibrium with the unvaporized liquid.
Chromatographic Analysis
A Chromatographic analysis is a simulated distillation performed by
passing a small amount of totally vaporized sample through a packed
gas chromatograph column. The relative amounts of the sample that
appear in each standard "chromatographic" hydrocarbon group
(paraffinic, aromatic and naphthaline groups, ranging from C6 to C30)
are then detected and reported.
4-6
HYSYS Oil Manager
4-7
4.2.3 Data Reporting Basis
All of the distillation analyzes described above are reported using one of
the following fractional bases (assay basis):
•
•
•
Liquid volume percent or liquid volume fractions
Mole percent or mole fractions
Mass percent or mass fractions
HYSYS accepts TBP and Chromatographic analyzes in any one of the
three standard bases. However, due to the form of the API Data Book
conversion curves, EFV, ASTM D86 and ASTM D1160 distillations must
be supplied on a liquid volume basis, and ASTM D2887 are only
reported on a weight basis.
4.2.4 Physical Property Assay Data
Refer to Appendix B Petroleum Methods/
Correlations for information
on the correlations used in the
Oil Environment.
As you supply more information to HYSYS, the accuracy of the
Petroleum Characterization increases. Supplying any or all of bulk
molecular weight, bulk density or bulk Watson (UOP) K factor increases
the accuracy of your hypocomponent properties. Appropriately, if you
supply laboratory curves for molecular weight, density and/or viscosity,
the accuracy increases further.
If you cannot supply property curve data, HYSYS generates internal
curves using the available information. This information is applied
using correlations. You can change the default set of property
correlations as required.
4.2.5 Property Curve Basis
Physical property analyzes are normally reported by a laboratory using
one of the following two conventions:
•
•
An Independent assay basis where the property assay volume
fractions do not correspond on a one-to-one basis with the
distillation assay fractions.
A Dependent assay basis, where a common set of assay
fractions are utilized for both the distillation curve and the
physical property curves.
4-7
4-8
Oil Characterization
Note that physical properties are average values for the given range, and
hence are midpoint values. Distillation data reports the temperature
when the last drop of liquid boils off for a given assay range; therefore
distillation is an endpoint property. Since all dependent input property
curves are reported on the same endpoint basis as the distillation curve,
they are converted by HYSYS to a midpoint basis. Independent property
curves are not altered in any manner before being used in the
characterization, since they are already defined on a midpoint basis.
4.2.6 Common Laboratory Data Corrections
With ASTM D86 data, correction procedures are available to modify the
laboratory results for both barometric pressure and thermal cracking
effects, which result in the degradation of the sample at high distillation
temperatures. These corrections are sometimes performed by the
laboratory. If the corrections have not already been applied, the
Characterization procedure has options available to apply the necessary
corrections before commencing calculations.
4.2.7 Default Correlations
When you begin a petroleum characterization session, HYSYS already
has a set of default correlations for generating physical and critical
properties of the hypocomponent. You may change any of the
correlations at any time.
Refer to Section 4.8.2 - Correlation Set View for a listing of available
correlations or Appendix B - Petroleum Methods/Correlations for a
description of each correlation.
4-8
HYSYS Oil Manager
4-9
4.3 Petroleum Fluids
Characterization Procedure
4.3.1 Initialization
Before entering the Oil Characterization environment, you are required
to create a fluid package with a specified Property Package at the very
minimum. Note that the Associated Property Package must be able to
handle hypothetical components (i.e., a Steam Package is not allowed).
If you want to use library components to represent the Light Ends
portion of your assay, it is best to select the components prior to
entering the Oil Characterization environment (if you forget to do this,
you can return later to the Components tab and select the components).
The fluid package that is used
in the Oil Characterization
environment is displayed in the
Associated Fluid Package
drop-down list on the Oil
Manager tab of the Simulation
Basis Manager view.
The Oil Manager tab of the Basis Manager view is shown below:
Figure 4.1
The Associated Fluid Package for the Oil serves two primary functions:
•
•
Provides the light end components.
Identifies to which Fluid Package the Hypo group (oil) is being
installed.
4-9
4-10
Petroleum Fluids Characterization
When you install the oil into a stream, HYSYS always places this stream
in the main flowsheet. For this reason, the associated Fluid Package
must be the fluid package used by the main flowsheet.
If you also want to install the hypocomponent into a subflowsheet, this
must be done on the Components tab of the Sub-Flowsheet fluid
package (Hypothetical page, Add Group or Add Hypo button). If the
sub-flowsheet uses the same fluid package as the main flowsheet, then
this action is not necessary, as the hypocomponent is added to the fluid
package once an oil stream is installed.
If you are going to transfer an oil stream between flowsheets with
different fluid packages, ensure that the hypocomponent is installed in
each flowsheet fluid package. Note that if you have not defined the same
components in each fluid package, HYSYS will transfer only the
compositions for those components that are available, and will
normalizes the remaining compositions.
The fluid package that is used in the Oil Characterization environment
can be selected from the Associated Fluid Package drop-down list. To
enter the Oil environment, select the Enter Oil Environment button as
shown in Figure 4.1, or select the Oil Environment button from the
toolbar. The following figure illustrates the make-up of a typical oil:
Figure 4.2
Assay 1
Bulk Properties
•
•
•
•
Molecular Weight
Mass Density
Watson (UOP) K
Viscosity
•
•
•
•
•
•
•
TBP
ASTM D86
ASTM D1160
ASTM D86-D1160
ASTM D2887
EFV
Chromatograph
Assay 2
OIL
(blend)
Assay 3
Boiling Point Curve
Property Curves
Dependent/
Independent
4-10
• Molecular Weight
• Mass Density
• Viscosity
HYSYS Oil Manager
4-11
An Oil or Blend is comprised of any number of Assays. Each individual
Assay contains specific information with respect to the Bulk Properties,
Boiling Point Curve and Property Curves. For the Bulk Properties, you
may supply Molecular Weight, Mass Density, Watson (UOP) K factor
and/or Viscosity. You can provide the Boiling Point curve in any one of
the formats displayed in the Figure 4.2. During calculations, HYSYS
automatically converts all curves to a TBP basis. You also have the
option of supplying Molecular Weight, Mass Density, and/or Viscosity
curves.
It is a good idea to open the
Trace Window before you start
the characterization, since it
displays important information
during Oil Characterization
calculations.
There are three general steps you must follow when creating an oil:
1.
characterize assay
2.
generate hypocomponent
3.
install oil in flowsheet.
4.3.2 Step One - Characterize Assay
Enter the petroleum assay data into HYSYS via the Assay tab of the Oil
Characterization view. HYSYS uses the supplied Assay data to generate
internal TBP, molecular weight, density and viscosity curves, referred to
as Working Curves. See Section 4.5 - Characterizing Assays for more
details.
4.3.3 Step Two - Generate Hypocomponents
Hypocomponents are generated from the Working Curves via the Cut/
Blend tab of the Oil Characterization view. This process is explained in
Appendix B - Petroleum Methods/Correlations. See Section 4.6 Hypocomponent Generation for the procedure.
4.3.4 Step Three - Install Oil
Once the Blend is characterized satisfactorily, install hypocomponent
into your HYSYS case via the Install Oil tab of the Oil Characterization
view. You can install the oil as a defined stream by providing a Stream
name. The hypocomponent is also added to a distinct Hypo group and
to the associated fluid package. See Section 4.8.3 - Install Oil Tab for
more details.
4-11
4-12
Petroleum Fluids Characterization
4.3.5 User Property
In addition to the three basic steps required to characterize an oil in
HYSYS, user properties can be added, modified, deleted, or cloned. User
Properties can be created from the Oil Manger or in the Basis
Environment. A user property is any property that can be calculated on
the basis of composition. Refer to Section 4.7 - User Property for more
information.
4.3.6 Correlations
Correlations can be selected via the Correlation tab of the Oil
Characterization view. HYSYS allows you to select from a wide variety of
correlations used in both the determination of working curves and in
the generation of hypocomponent. See Section 4.8.1 - Correlation Tab.
All of the information used in generating your hypocomponent is stored
with the case. This includes: Assays and their associated Options,
Property Curves and Bulk Properties, User Properties, the Correlations
used for generating the pseudo-components, the Constituent oils (with
flow rates) for blends, and the flowsheet stream in which each oil was
installed. This information is available the next time you open the case.
4-12
HYSYS Oil Manager
4-13
4.4 Oil Characterization View
When you enter the Oil Characterization environment, the following
view appears:
Figure 4.3
This view is the Oil Characterization environment. There are five tabs
which represent the main areas of the environment and are described
below:
Tab
Description
Assay
Add, edit, delete, clone, import or export Assays (see Section 4.5 Characterizing Assays).
Cut/Blend
Add, edit, delete or clone Blends (see Section 4.6 Hypocomponent Generation).
User Property
Add, edit, delete or clone User Properties (see Section 4.7 - User
Property).
Correlation
Add, edit, delete or clone Correlation Sets (see Section Section
4.8.1 - Correlation Tab).
Install Oil
Install hypocomponent into a stream in a HYSYS case (see Section
4.8.3 - Install Oil Tab).
4-13
4-14
Oil Characterization View
The Clear All, Calculate All, and Oil Output Settings... buttons are
available on any tab of the Oil Characterization property view.
•
•
If you select the Calculate All button, HYSYS calculates all
Assays and Blends. This option is useful if you have several
Assays and/or Blends and you want to see the global effect of a
change in the correlation.
If you select the Clear All button, HYSYS displays the following
warning:
Figure 4.4
If you want to delete all Oil Characterization information select Yes.
•
Selecting the Oil Output Settings... button results in the Oil
Output Settings property view.
Oil Output Settings View
On this view, you can set the initial boiling point (IBP) and final boiling
point (FBP) cut points on a liquid volume, mole or mass percentage
basis. These values are used to determine the initial and final boiling
temperatures of the TBP working curve. The default values are 1% for
the IBP and 98% for the FBP.
Figure 4.5
4-14
HYSYS Oil Manager
4-15
If for example, an IBP value of 1% is specified, the initial boiling point
becomes the weighted average boiling temperature of all components
that boil off in the first volume percent. The final boiling point is
determined in a similar manner. If 98% is used for the FBP, the final
boiling temperature becomes the weighted average boiling temperature
of all the components that boil off in the last 2 volume percent. The ends
of the curve are ’stretched’ to fill the assay range of 0 to 100%.
Oil Input settings are
accessed through the
Preferences view.
On the Oil Output Settings view, you can select the default ASTM D86
Interconversion Method TBP conversion type from the Default D86
Curve Type drop-down list:
•
•
•
•
API 19741
API 19872
API 19943
Edmister-Okamoto 19594
You can also select the ASTM D2887 Interconversion method from the
following:
•
•
•
API 19875
API 1994 Indirect6
API 1994 Direct7
The Oil Output Settings are saved along with your simulation case. They
can be accessed either within the Oil manager or through the
Simulation menu bar option in the Main Simulation environment.
Changing the IBP and FBP in the Oil Output Settings will affect the
following calculations:
•
•
•
•
•
Blend Properties Table and Plots
Boiling Point Utility
Cold Properties Utility
Column specs (Cut Point, Gap Cut Point, Flash Point, RON
Point)
Column Profiles
4-15
4-16
Characterizing Assays
When IBP and FBP changes are made, all necessary calculations are
automatically performed.
Note that the ASTM D86 and ASTM D2887 interconversion methods do
not affect column specifications, since each related columnspec has its
own independent setting. If you want to change the column
specifications, click the Change Interconversion Methods for Existing
Column Specs button. HYSYS asks you to confirm that you want to
globally impose these changes.
4.5 Characterizing Assays
Refer to Section 4.9 - TBP
Assay - Example for
characterizing assays.
The Assay tab of the Oil Characterization view is shown below:
Figure 4.6
C
HYSYS does not prompt for
confirmation when deleting an
assay, so be careful when you
are using this command.
However, HYSYS does not
delete an assay that is being
used by a blend.
4-16
The Available Assays are listed in the left portion of the view. The
following Assay manipulation buttons are available:
Button
Description
View
Edit the currently highlighted Assay
Add
Create a new Assay
Delete
Erase the currently highlighted Assay
Clone
Create a new Assay with the same properties as the currently
highlighted Assay. HYSYS immediately opens a new Assay view
HYSYS Oil Manager
Imported and Exported
assays have a filename form
*.oil.
Button
Description
Import
Bring a saved assay into the current case
Export
Save an assay to disk so that it can be used in other cases
4-17
Note that for a highlighted Assay, you can edit the name in the Name
field and provide a description in the Description textbox found in Assay
Information group.
To create a new assay or edit an existing assay you can click the Add or
View buttons, respectively. This opens the Assay property view for the
new or existing assay.
When the Oil Input Preferences button under the Assay Information
group is selected, the Session Preferences view opens to the Oil Input
tab. From here you can set the input defaults for your case.
Figure 4.7
When a new case is created, the methods specified in the Oil Input
settings initialize the Oil Output settings. However, any changes made
afterwards to either settings group are independent.
4-17
4-18
Characterizing Assays
Assay Property View
The Assay property view is shown below:
Note that the appearance of
the Assay property view
depends on how you define
the assay in the Assay
Definition group and which
radio button is selected in the
Input Data group.
Figure 4.8
The Assay property view consists of seven tabs, which are described
below:
4-18
Tab
Description
Input Data
Allows you to define and specify the Assay.
Calculation Defaults
Allows you to set the calculation methods and extrapolation
methods for the assay and assay property curves.
Working Curves
Displays a table of Assay Working curves.
Plots
Allows you to view any of the input assay curves in graphical
form.
Correlations
Allows you to edit the individual property conversion methods
used.
User Curves
Allows you to attach available user properties to the assay.
Notes
Allows you to attach relevant comments to the assay.
HYSYS Oil Manager
4-19
There are four objects found at the bottom of the property view and are
described below:
Object
Description
Name
You can provide the name of the Assay in the Name cell (maximum
12 characters).
Assay Status
The status bar is displayed at the bottom of the screen:
• Assay Was Not Calculated. You have not provided enough
Assay information to determine a solution (or you have
enough information and have not clicked the Calculate button).
• Assay Was Calculated. You have provided Assay
information, clicked the Calculate button, and obtained a
solution.
• An Error Was Found During Calculation. The Trace Window
usually shows a description of the type of Error.
Calculate
Select this button to calculate the Assay.
Delete
Select this buttons to delete the current Assay.
There is no confirmation
when you delete an assay,
unless it is being used by a
blend, in which case you
cannot delete it.
The following sections outline each of the tabs contained within the
Assay view (accessed via the View or Add button).
4.5.1 Input Data Tab
The minimum amount of information that HYSYS requires to
characterize a petroleum fluid is either:
•
a laboratory distillation curve
OR
The Watson (UOP) K factor is
an approximate index of
paraffinicity, with high values
corresponding to high degrees
of saturation:
3 Mean Avg. BP
K = --------------------------------------sp gr 60F / 60F
where the mean average
boiling point is in degrees
Rankine.
•
two of the following three bulk properties:
• Molecular Weight
• Density
• Watson (UOP) K factor
However, any additional information such as distillation curves, bulk
properties and/or property curves, should be entered if possible. With
more supplied information, HYSYS produces a more accurate final
characterization of your oil.
When you open the Assay view to the Input Data tab, all that is displayed
is the Assay Data Type and Bulk Properties drop-downs. New input
fields are added as you specify the information for your oil.
4-19
4-20
Characterizing Assays
The Input Data tab is shown below:
Figure 4.9
The layout of Input Data group depends largely
on the settings you choose in this group.
Specify which
individual
Input Data
curves are to
be included.
Options
related to the
Assay Data
Type are
displayed in
this area.
Depending on the specifications made in the Assay
Definition group. These radio buttons become visible.
Each radio button makes a different entry field visible.
The entry
fields
displayed in
this table
depend on
which radio
button is
selected.
For each of the three property curves, Molecular Weight, Density and
Viscosity, you have the following options: Not Used, Dependent, or
Independent. If you switch the status to Not Used after you have entered
assay data, all your data for that property curve is lost when you return
your selection to Dependent or Independent.
The Input Data tab is split into two groups: the Assay Definition and
Input Data groups. The Assay Definition group is where the assay type
and use of property curve, light ends data and bulk properties are
defined. The Input Data group is where the distillation, property curve,
light ends and property data is actually inputted.
4-20
HYSYS Oil Manager
4-21
Light Ends Handling & Bulk Fitting
If you have a light-ends analysis along with light-ends free input curves
and total bulk properties or light-ends free bulk properties you can use
the HYSYS oil manager to combine the light-ends analysis with the
light-ends free input curves to match the specified bulk properties. This
functionality is clearly seen in the case of chromatographic input, where
you may want to input the light-ends along with the C6+ as the
chromatographic data groups. Because of the nature of the analysis, the
chromatographic data is light-ends free.
Light Ends Analysis Versus Calculated TBP Curve
Ideally, for the light-ends free distillation input curve, the TBP at 0%
should coincide with the highest NBP in the light-ends components
with non-zero compositions, see Case B in Figure 4.10. However, due to
imperfect input data or extrapolation, the calculated TBP at 0% may be
lower than the top NBP for light ends (Case A in Figure 4.10) or higher
than the top NBP for light ends (Case C in Figure 4.10). To avoid
overlapping or discontinuity, these two cases must be properly handled.
Figure 4.10
4-21
4-22
Characterizing Assays
In Case A, the highest temperature of the non-zero component in light
ends is above the TBP at 0%. In this case, we need to eliminate the
points having TBP lower than the top light-ends temperature. After the
elimination, the remaining portion of the light-ends free TBP curve are
re-scaled to 100%, and then a new set of standard 51 points calculation
tables are regenerated from the remaining portion of the corresponding
curves.
In Case C, the top light-ends temperature is below the TBP at 0%. Since
the extrapolation may not be accurate, more trust is put on the lightends analysis and hence assign the top light-ends temperature as the
TBP at 0%. To avoid a sudden jump in the distillation curve, the first 20%
of the distillation curve is also smoothed.
Curve Partition for Bulk Property Fitting
To allow piece-wise fitting for a bulk property, a property curve is
divided into three sections: head, main, and tail. The ending % of the
head section and beginning % of the tail section can be specified. Each
section can have an independent adjusting weight factor as shown in
the figure below.
Figure 4.11
4-22
HYSYS Oil Manager
4-23
For piecewise bulk property fitting there are two concerns to be
addressed. First, since each section can have an independent adjusting
weight factor, there may be a discontinuity at the boundary of the two
sections. Second, how to ensure relatively fast convergence with uneven
adjustment of the property concerned. For the first concern,
discontinuity is avoided by using linear interpolation between two
sections. For the second concern, the weight factor is normalized first
and then the following equation is used to calculate the new point
property value from the old point property value:
New [ i ] = [ 1 + Wt [ i ] × ( Ratio – 1 ) ] × Old [ i ]
where:
(4.1)
New[i] = the new property value at point i
Wt[i] = the normalized weight factor at point i
Ratio = the calculated uniform adjusting ratio
Old[i] = the old property value at point i
HYSYS allows you to specify if a given curve contains light-ends
contributions, set if a specified bulk property contains light-ends and
partition a property curve so that some sections can be adjusted more
than others.
The Light Ends Handling & Bulk Fitting Options view is accessed by
clicking the Light Ends Handling & Bulk Fitting Options button.
Figure 4.12
4-23
4-24
Characterizing Assays
The light ends handling and bulk fitting options are described below:
Column
Description
Input Curve
Displays all the possible input curves, including user property
curves.
Curve Incl L.E.
Specifies if the corresponding input curve includes light ends. If
an input curve is not used, the corresponding checkboxes are
grayed out.
Bulk Value
Specifies the bulk value for the corresponding input curve.
Bulk Value Incl L.E.
Specifies if a given bulk value contains the contributions of light
ends. If no light end compositions are given these checkboxes
are grayed out.
The last five columns are used for piece-wise bulk property fitting.
When fitting a given bulk property value the internal calculation curve,
either based on the input curve or calculated from a correlation, is
divided into three sections. Each of the three sections can be
independently adjusted.
Column
Description
Head%
Specifies the ending percent for the head section on the input
basis.
Head Adj Wt
Specifies the corresponding relative bulk fit adjusting weight
factor from 0 to 10, where 0 means no adjusting at all.
Main%
Specifies the ending percent for the main section of the input
basis.
Main Adj Wt
Specifies the corresponding relative bulk fit adjusting weight
factor from 0 to 10, where 0 means no adjusting at all.
Tail Adj Wt
Specifies the corresponding relative bulk fit adjusting weight
factor from 0 to 10, where 0 means no adjusting at all.
When fitting a given bulk value, at least one section must be adjustable.
Therefore, at least one section must have a non-zero percentage range
and a non-zero adjusting weight factor. Since the adjusting weight
factors are relative, it is the weight factor ratios among the three sections
that matter.
The Apply smart bulk fitting on molecular weight and mass density
button allows you to achieve the best bulk fitting on mass density and
molecular weight input curves. If the button is selected, the mass
density and molecular weight rows are disabled and the values appear
in black.
4-24
HYSYS Oil Manager
4-25
If the input for either molecular weight or mass density curves is less
than 95% on a user defined basis, only the extrapolated tail is adjusted
to match the user specified bulk value. If the input is more than or equal
to 95% on the user defined basis, the entire curve will be adjusted to
match the bulk value specified.
The user input data is the most reliable data available, and hence should
not be adjusted to match the bulk value as long as there is enough
extrapolated data to adjust.
When only the tail is adjusted, it is ensured that the upper end point is
no lower than the linear extrapolation of the last two points. This means
that in most cases, the extrapolated portion of the curve is concave, i.e.,
the curvature is positive. If the bulk value is given such that the
extrapolated values are below the linear extrapolation values, the whole
curve is adjusted and the following warning message is displayed:
“Curve is normalized due to the inconsistency between the supplied
curve and bulk data.”
If the upper limit value is reached when adjusting the molecular weight
or density curve and the specified bulk value is still not matched, no
adjustment is made and the following message appears: “No exact
match, upper limit reached”. For molecular weight, the upper limit
value is ten times that of the bulk value. For mass density, the upper
limit is three times that of the bulk value.
If a bulk molecular weight or mass density is given without a
corresponding input curve, the whole calculated curve will be adjusted.
The 95% input is an artificial dividing line to decide if only the tail is
adjusted or the whole curve is adjusted. If the user input curve crosses
the dividing line, there is a chance to have a sudden change in the
behaviour. If this occurs, you can overcome the problem by manually
setting the bulking fitting options without using the smart option. To
achieve similar results manually, you can set the Head Adj Wt and Main
Adj Wt to zero, set the Main % to the desired tail starting percent, and
leave the Tail Adj Wt to its default value of 1.0.
4-25
4-26
Characterizing Assays
Bulk Properties Definition
These bulk properties are optional except when distillation data is not
available (you have selected None as the Data Type). If you do not
supply any distillation data, you must supply two of the three initial bulk
properties (Molecular Weight, Mass Density or Watson (UOP) K factor)
for HYSYS to create a "typical" TBP curve. This TBP curve is generated
based on a Whitson molar distribution model.
If you are supplying property curves and you supply a bulk molecular
weight, density, or Watson K factor, HYSYS smoothes and adjusts the
corresponding curves to match the supplied bulk properties. Note that
this procedure is performed whether you supply property curves or they
were internally generated by HYSYS.
Assay Definition Group
The Assay Definition group contains only one object involved in the
specification of Bulk Properties: the Bulk Properties drop-down. The
Bulk Properties drop-down list has two options:
4-26
Option
Description
Used
If an Assay Data Type is not selected, the Input Data group displays
the Bulk Prop table along with the Molecular Weight of lightest
component field. However, if an Assay Data Type is selected, a Bulk
Props radio button appears in the Input Data group. When this radio
button is active the Bulk Prop table is displayed.
Not Used
No bulk properties are considered in the oil characterization
calculations.
HYSYS Oil Manager
4-27
Input Data Group
The Input Data group that appears when Used is selected for bulk
properties is shown in the figure below:
Figure 4.13
It consists of two objects: the Bulk Properties table and Molecular
Weight of lightest component field.
The Molecular Weight of lightest component field is only visible when
the Assay Data Type selected is None.
The Bulk Properties table has several fields:
The Watson (UOP) K factor is
an approximate index of
paraffinicity, with high values
corresponding to high degrees
of saturation:
3 Mean Avg. BP
K = --------------------------------------sp gr 60F / 60F
where:
Mean Avg. BP = the
mean average
boiling point is in
degrees Rankine.
Bulk Properties
Description
Molecular
Weight
The Molecular Weight must be greater than 16.
Standard
Density
The mass density must be between 250 and 2,000 kg/m3 (note that
units can be mass density, API or specific gravity, chosen from the
drop-down list).
Watson (UOP)
K factor
This factor must be between 8 (highly aromatic or naphthenic) and
15 (highly paraffinic). Only field units are used here.
Bulk
Viscosities
The bulk viscosity type and the temperature at two reference points.
4-27
4-28
Characterizing Assays
Defining Assay Types
Assay Definition Group
To define Assay types, select a type in the Assay Definition group using
the drop-down list.
Assay types that are available are described in the table below:
You can specify the ASTM
D86/TBP Interconversion
Method (API 19741, API 19872,
API 19943 or EdmisterOkamoto 19594) on the
Calculation Defaults tab. With
the ASTM D86 Assay type you
can also correct for thermal
cracking as well as for
elevation.
Assay Type
Description
TBP
True boiling point distillation data at atmospheric pressure. Once
you have selected this option, the TBP Distillation Conditions group
is displayed. The default distillation conditions are atmospheric,
however, you can enable Vacuum Distillation for sub-atmospheric
conditions by activating the Vacuum radio button. The default
pressure in this case is 10 mmHg (ASTM standard). When you
supply sub-atmospheric data, it is automatically corrected from
vacuum to atmospheric conditions using procedure 5A1.13 (without
K-correction) from the API Data Book.
ASTM D86
Standard ASTM D86 distillation data at atmospheric pressure.
Note that you must provide data on a liquid volume basis.
ASTM D1160
ASTM D1160 distillation data. After you have selected this option,
the ASTM D1160 Distillation Conditions group is displayed. By
default, the Vacuum radio button is selected and the Vacuum
Distillation Pressure is set to 10 mmHg (ASTM standard). When
ASTM D1160 Vacuum data is supplied, HYSYS will first convert it to
TBP vacuum data, and then convert this to TBP data at 760 mmHg
using procedure 5A1.13 of the API Data Book.
Note that you must provide data on a liquid volume basis.
4-28
ASTM D86D1160
This is the combination of the ASTM D86-D1160 data types. The
options for ASTM D86 and ASTM D1160 are similar to the
descriptions above. You must provide data on a liquid volume basis.
ASTM D2887
Simulation distillation analysis from chromatographic data, reported
only on a weight percent basis at atmospheric pressure. On the
Calculation Defaults tab, you have the choice of conversion method
(API 19875, API 1994 Indirect6, API 1994 Direct7).
Chromatograph
A gas chromatograph analysis of a small sample of completely
vaporized oil, analyzed for paraffin, aromatic and naphthenic
hydrocarbon groups from C6 to C30. Chromatographic analyses may
be entered on a mole, mass, or liquid volume basis. With this option,
you enter Light Ends, Bulk and Chromatographic analysis data.
(See Chromatographic Assay Input below).
EFV
Equilibrium flash vaporization curve; this involves a series of
experiments at constant atmospheric pressure, where the total
vapour is in equilibrium with the unvaporized liquid.
None
No distillation data is available; HYSYS generates a TBP curve from
bulk property data. With this option, you only enter bulk data.
HYSYS Oil Manager
4-29
Input Data Group
The conversion procedure
from various assay types to a
TBP curve is based on Figure
3-0.3 of the API Data Book.
The Input Data group displayed when the Distillation radio button is
selected depends on the Assay type you have selected in the Assay
Definition group.
Distillation Data
For Assay Type options TBP, ASTM D86, ASTM D1160, ASTM D2887 and
EFV, the procedure for entering boiling temperature information is
essentially the same - you are required to enter at least five pairs of Assay
Percents and boiling Temperatures. The Distillation input table is
exactly the same for each of these options.
You can view and edit the assay boiling Temperature input table by
selecting the Distillation radio button and clicking the Edit Assay button.
For the ASTM D86-D1160 characterization procedure, you are required
to enter boiling temperature information for both the ASTM D86 and
ASTM D1160 data types. This procedure averages the ASTM D86 curve
and ASTM D1160 curve in the area where they overlap.
For example, in the combined ASTM D86-D1160 input form shown on
the left, the last recorded ASTM D86 assay point is at 30 vol%, and the
first reported ASTM D1160 data point is at 10 vol%. Therefore, the
resulting TBP curve will represent the average of the two curves between
10 vol% and 30 vol%. Each curve must contain a minimum of 5 data
points.
Chromatographic Assay Input
This distillation option allows you to enter a standard laboratory
chromatographic analysis directly. The only required input is the assay
fraction for each chromatographic hydrocarbon group in the paraffin,
aromatic, and naphthenic families. The required minimum of five
points can be any combination of points from the three PNA groups.
The normal boiling point of each hydrocarbon group is displayed in the
PNA tables.
4-29
4-30
Characterizing Assays
Chromatographic analyses may be entered on either a mole, mass, or
liquid volume basis, with the best results obtained when the input
fractions are on a mole fraction basis.
A typical C6+ liquids chromatographic analysis is shown in the
chromatographic input form below.
Figure 4.14
You may also supply bulk
property data (see Bulk
Properties in Section 4.5.1 Input Data Tab for details).
4-30
Note that chromatographic analyses are typically performed after the
light ends of the original sample are removed. If you have a Light Ends
analysis in this case, refer to Light Ends Handling & Bulk Fitting for
details.
HYSYS Oil Manager
4-31
Assay Input - No Distillation Data Available
HYSYS uses the Whitson
Molar Distribution model that
requires at least two of the
three bulk properties (not
including bulk viscosities) to
produce an average TBP
distribution.
When a distillation analysis is not available, HYSYS generates a typical
TBP curve based on supplied bulk properties (molecular weight, mass
density, and Watson (UOP) K factor). You have the option of specifying
the molecular weight of the lightest component in the mixture, which
may help in generating more accurate TBP curves for heavy petroleum
fluids.
Figure 4.15
Although accurate enough for heat balance applications, caution should
be exercised when the Whitson option is used to produce
hypocomponent for fractionation calculations. This method realistically
supplies accuracy sufficient only for preliminary sizing calculations.
For condensate with only bulk data available for the C7+ fraction,
experience has shown a considerable increase in accuracy by
representing the fraction with several hypocomponent as opposed to a
single hypothetical component with the bulk properties.
Refer to Bulk Properties Definition (earlier in this Section) for details on
entering bulk property data, particularly in regards to Bulk Viscosities.
4-31
4-32
Characterizing Assays
General Guidelines
Some general guidelines are provided below:
•
•
•
•
•
There is no limit to the number of assay data points that you may
enter for TBP, ASTM D86, ASTM D1160, ASTM D86-D1160
ASTM D2887 or EFV analyses. Data points may be input in any
order, as HYSYS automatically sorts your input data.
HYSYS requires a minimum of 5 data points for all assays.
Depending on the shape of the input curve, intermediate values
for HYSYS' internal TBP working curve are interpolated using
either a third or fourth order LaGrange polynomial fit. The points
outside your data are extrapolated using the extrapolation
method which you select on Calculation Defaults tab: Least
Squares, Lagrange or Probability.
Each time you change the Basis or Extrapolation method, the
Assay needs to be recalculated.
TBP, EFV, and Chromatographic laboratory assay values may be
entered on a liquid volume, mole or weight basis. Liquid volume
is the default basis for TBP and EFV input, and mole is the
default basis for Chromatographic input. Due to the form of the
conversion curves in the API Data Book, you must supply your
ASTM D86 and ASTM D1160 distillation data on a liquid volume
basis. ASTM D2887 is only reported on a weight percent basis.
If you are editing an assay, redefining the Basis does not alter
your supplied assay values. For example, consider an assay
curve with 10, 30, 50, 70 and 90 liquid volume percent points. If
you change the Basis to mass percent, the assay percents and
temperature are not changed. The temperature you supplied for
10% liquid volume is retained for 10% mass.
HYSYS generates all of its physical and critical properties from an
internally generated TBP curve at atmospheric conditions. Regardless
of what type of assay data you provide, HYSYS always converts it to an
internal TBP curve for the characterization procedure. Note that the
internal TBP curve is not stored with the assay.
4-32
HYSYS Oil Manager
4-33
Light Ends Definition
Light Ends are defined as pure components with low boiling points.
Components in the boiling range of C2 to n-C5 are most commonly of
interest. Generally, it is preferred that the portion of the oil’s distillation
assay below the boiling point of n-C5 be replaced with discrete pure
components (library or hypothetical). This should always yield more
accurate results than using hypocomponent to represent the Light Ends
portion.
Assay Definition Group
HYSYS provides three options to account for Light Ends, which are as
follows:
Option
Description
Ignore
HYSYS characterizes the Light Ends portion of your sample as
hypocomponents. This is the least accurate method and as such, is
not recommended.
Auto Calculate
Select this when you do not have a separate Light Ends analysis but
you want the low boiling portion of your assay represented by pure
components. HYSYS only uses the pure components you selected
in the fluid package.
Input
Composition
Select this when you have a separate Light Ends assay and your
petroleum assay was prepared with the light ends in the sample.
HYSYS provides a form listing the pure components you selected in
the fluid package. Input your data on a non-cumulative basis.
To correctly employ the Auto Calculate or Input Composition options,
you should either pick library components, or define hypothetical
components to represent the Light Ends before entering the Oil
Characterization environment. If you have selected the Auto Calculate
method without specifying light ends, HYSYS calculates the oil using
only hypocomponent, just as if you had selected Ignore. If you selected
Input Composition, there are no light end components for which you can
supply compositions. You can go back to the Fluid Package view at any
time and define your light components.
The following sections provide a detailed explanation of Light Ends,
how the laboratory may account for them, how they are reported and
how HYSYS utilizes this information. It is recommended that you read
this information to ensure that you are selecting the right options for
your assay.
4-33
4-34
Characterizing Assays
Laboratory Assay Preparation
During TBP and ASTM laboratory distillations, loss of some of the Light
Ends components from the sample frequently occurs. To provide
increased accuracy, a separate Light Ends assay analyzed using
chromatographic techniques may be reported.
Regardless of whether a separate light ends analysis was provided, your
overall assay is either Light Ends Included or Light Ends Free. The way in
which your sample was analyzed affects both the results and the
method you should use to input the information for your
characterization.
Light Ends Portion Included in Assay
In this case, your assay data was obtained with the light ends
components in the sample; i.e., the assay is for the whole sample. The
IBP temperature for your assay is lower than the boiling point of the
heaviest pure light end component. This corresponds to an IBP
approximately equal to the weighted average boiling point of the first
1% of the overall sample. For example, if the lightest component is
propane and it makes up more than 1% of the total sample, the IBP of
the assay is approximately -45°F (the normal boiling temperature of
propane).
If the Light Ends were included in your overall assay, there are two
possibilities:
4-34
Option
Description
Light Ends Analysis
Supplied
If you know that light ends are included in your assay, select
the Input Composition option from the Light Ends group, and
enter the composition data directly into the Light Ends
composition view.
No Light Ends
Analysis Available
If you do not have a laboratory analysis for the light ends
portion of your assay, then you should use the Auto Calculate
option. HYSYS represents the light ends portion of your assay
as discrete pure components, automatically assigning an
appropriate assay percentage to each. If you do not do this
(you select Ignore), HYSYS represents the Light Ends portion
of the assay as petroleum hypocomponent.
HYSYS Oil Manager
4-35
Assay is Light Ends Free
Your assay data was analyzed with the Light Ends components removed
from the sample, or the assay was already adjusted for the Light Ends
components. The IBP temperature for your assay is higher than the
boiling point of the heaviest pure light end component - typically your
assay is for the C6+ fraction only and the IBP temperature is somewhat
above 95°F (36°C).
If your distillation data is light-ends free and you have separate lightends analysis data, you can use HYSYS oil characterization to combine
the two. The advantage of doing this is that the bulk properties, if
available, will be fitted and matched accurately. To do the combining,
you need to input the distillation data and light ends data as usual and
then click the Light Ends Handling & Bulk Fitting Options button
accessible from Input Data or User Curves tab. In the Light-Ends
Handling & Bulk Fitting Options view, uncheck the Curve Incl L.E.
checkbox for distillation. If you have bulk properties to fit, you need to
indicate if the bulk values include light ends by checking or un-checking
the Bulk Value Incl L.E. checkboxes.
4-35
4-36
Characterizing Assays
Input Data Group
When you have selected Input Composition as the Light Ends option
and you select the Light Ends radio button in the Input Data group, the
following view appears.
Figure 4.16
There are three objects associated with the Light Ends Input and are
described below:
4-36
Object
Description
Light Ends Basis
Allows you to select the basis for the Light Ends analysis on a
mole, mass, or liquid volume basis. The way in which you enter
the rest of the light ends data depends on whether you select a
percent or flow basis:
• Percent. Enter the percent compositions for the Light
Ends on a non-cumulative basis. HYSYS calculates the
total Light Ends percentage by summing all of the Light
Ends assay data. If the sum of the light ends assay
values is equal to 100 (you have submitted normalized
data), you must enter the Percent of light ends in the
Assay. This value must be on the same basis as the
distillation data. Note that if the sum of the light ends is
equal to 1.0000, HYSYS assumes that you have entered
fractional data (rather than percent), and you are
required to enter the Percent of light ends in the Assay.
• Flow. Enter the flows for each component, as well as the
percent of light ends in the assay.
HYSYS Oil Manager
Object
Description
Light Ends
Composition matrix
The matrix consists of the three fields:
• Light Ends. Displays all pure components or
hypotheticals you selected in the associated fluid
package.
• Composition. The composition value of the associated
component is either entered (when Light Ends drop-down
is set to Input Composition) or automatically calculated
(when the Light Ends drop-down is set to Automatically
Calculated)
• NBP. The Normal Boiling Point of the associated
component or hypothetical.
Percent of lights
ends in Assay
The total percentage of light ends in the Assay. If the Light
Ends Basis selected is percentage (i.e., LiquidVolume%,
Mole% or Mass%), then this is automatically calculated. If the
Basis selected is flow based (i.e., Liquid Flow, Mole Flow or
Mass Flow), you are required to provide this value.
4-37
Auto Calculate Light Ends
Refer to Appendix B Petroleum Methods/
Correlations for a graphical
representation of the Auto
Calculate Light Ends removal
procedure.
The Auto Calculate extraction procedure internally plots the boiling
points of the defined Light Ends components on the TBP working curve
and determine their compositions by interpolation. HYSYS adjusts the
total Light Ends fraction such that the boiling point of the heaviest Light
End is at the centroid volume of the last Light Ends component. The
results of this calculation are displayed in Light Ends Composition
matrix. However, unlike when setting the Input Composition, the matrix
is not editable.
Physical Property Curves Specification
Physical property analyzes are normally reported from the laboratory
using one of the following two conventions:
•
•
An Independent assay basis, where a common set of assay
fractions is not used for both the distillation curve and physical
property curve.
A Dependent assay basis, where a common set of assay
fractions is used for both the distillation curve and the physical
property curves.
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4-38
Characterizing Assays
Note that physical properties are average values for the given range, and
hence are midpoint values. Distillation data reports the temperature
when the last drop of liquid boils off for a given assay range, and
therefore distillation is an endpoint property. Since all dependent input
property curves are reported on the same endpoint basis as the
distillation curve, they are converted by HYSYS to a midpoint basis.
Independent property curves are not altered in any manner as they are
already defined on a midpoint basis.
As with distillation curves, there is no limit to the number of data points
you provide. The order in which you input the points is not important,
as HYSYS sorts the input data. A minimum of five data points is required
to define a property curve in HYSYS. It is not necessary that each
property curve point have a corresponding distillation value.
Note that entering the 0 vol% point of a dependent curve contributes to
defining the shape of the initial portion of the curve, but has no physical
meaning since it is a midpoint property curve.
If a bulk molecular weight or mass density is going to be supplied, then
the corresponding Molecular Weight or Density working curve
generated from your input is smoothed to ensure a match. If you do not
enter bulk properties, then they are calculated from the unsmoothed
working curves.
Assay Definition Group
Each property curve type (i.e., Molecular Wt., Density and Viscosity) has
its own drop-down list in the Assay Definition group. Each drop-down
list contains the same three options and are described below:
4-38
Option
Description
Not Used
No property data is considered in the assay calculation.
Dependent
A common set of assay fractions is used for both the distillation
curve and the physical property curves.
Independent
A common set of assay fractions is not used for both the distillation
curve and physical property curve.
HYSYS Oil Manager
4-39
Input Data Group
Defining Molecular Weight and Density property curves as either
Independent or Dependent adds the corresponding radio button to the
Input Data group. However, defining a Viscosity property curve as
Independent or Dependent, HYSYS accepts viscosities for assay values
at two specified temperatures, with the default temperatures being 100
and 210°F. Activating the Molecular Wt., Density, Viscosity1 or
Viscosity2 radio buttons brings up the objects associated with the
specification of the respective property curve.
To enter the property curve data, simply select the radio button for the
property curve you want to input and click the Edit Assay button.
Molecular Wt. Curve
An example of a Molecular Weight assay is shown below:
Figure 4.17
Note that with Dependent Curves,
making a change to an Assay
Percent value automatically
changes this value in all other
Dependent curves (including the
Boiling Point curve).
The assay data is entered into the Assay Input Table view which is
opened when the Edit Assay button is selected. The form of this view is
the same regardless of whether you have specified Independent or
Dependent data. However, if you specified Dependent data, the Assay
Percents that you defined for the distillation data are automatically
entered in the table.
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4-40
Characterizing Assays
Depending on the shape of the curve, intermediate values for HYSYS’
internal working curve are interpolated using either a third or fourth
order Lagrange polynomial fit of your input curve, while points outside
your data are extrapolated. You can select the extrapolation method for
the fit of your input curve on the Calculation Defaults tab: Least
Squares, Lagrange or Probability.
Density Curve
An example of a Density assay is shown below:
Figure 4.18
The assay data is entered into the Assay Input Table view which is
opened when the Edit Assay button is selected. The form of this view is
the same regardless of whether you have specified Independent or
Dependent data. However, if you specified Dependent data, the Assay
Percents that you defined for the distillation data are automatically
entered in the table.
Depending on the shape of the curve, intermediate values for HYSYS’
internal working curve are interpolated using either a third or fourth
order Lagrange polynomial fit of your input curve, while points outside
your data are extrapolated. You may select the extrapolation method for
the fit of your input curve on the Calculation Defaults tab: Least
Squares, Lagrange (default) or Probability.
4-40
HYSYS Oil Manager
4-41
Viscosity Curves
HYSYS accepts viscosities for assay data at two specified temperatures
and therefore provides two radio buttons, Viscosity1 and Viscosity2, in
the Input Data group.
Figure 4.19
You can input data for one or both of the viscosity curves. Each radio
button brings up identical sets of objects, specific to assay data at the
designated temperature. Temperatures are entered in the Temperature
field with default values being 100 and 210°F. This implies that you have
determined the viscosity at 100 or 210°F for each of your assay portions
(10%, 20%, etc.).
In the Viscosity Curves group box, you can specify which curve (or both)
you want to use by selecting the appropriate radio button.
The Assay Input Table view, which is opened when the Edit Assay
button is selected, is filled in with the assay data. The form of this view is
the same regardless of whether you have specified Independent or
Dependent data. However, if you specified Dependent data, the Assay
Percents that you defined for the distillation data are automatically
entered in the table.
You may also define the viscosity unit type. The Units Type can be one
of the following:
Unit Type
Description
Dynamic
Conventional viscosity units (e.g., - cP)
Kinematic
Ratio of a fluid’s viscosity to its density (e.g.,- stoke, m2/s)
4-41
4-42
Characterizing Assays
Depending on the shape of the curve, intermediate values for HYSYS’
internal working curve are interpolated using either a third or fourth
order Lagrange polynomial fit of your input curve, while points outside
your data are extrapolated. You may select the extrapolation method for
the fit of your input curve on the Calculation Defaults tab: Least
Squares, Lagrange or Probability.
The defaults for a new assay may be modified by clicking the Oil Input
Preferences… button on the Assay tab of the Oil Characterization view.
The same view may also be accessed from the Simulation environment
by the following sequence:
1.
Select Tools-Preferences command from the menu bar.
2.
On the Session Preferences view, go to the Oil Input tab.
3.
Select the Assay Options page.
4.5.2 Calculation Defaults Tab
The Calculation Defaults tab is shown below:
Figure 4.20
4-42
HYSYS Oil Manager
4-43
Note that the internal TBP curve is not stored with the assay. The
Calculation Defaults tab contains three main groups:
•
•
•
Conversion Methods
Corrections for Raw Lab Data
Extrapolation Methods
Conversion Methods Group
HYSYS generates all of its physical and critical properties from an
internally generated TBP curve at atmospheric conditions. Regardless of
what type of assay data you provide, HYSYS always converts it to an
internal TBP curve for the characterization procedure. For ASTM D86
and ASTM D2887 assays types, you may specify the inter-conversion or
conversion methods used in the Conversion Methods group. The group
consists of the following two drop-down lists:
Field
Description
D86-TBP
(Interconversion)
There are four interconversion methods available:
• API 19741
• API 19872
• API 19943
• Edminster Okamoto 19594
D2887-TBP
(Interconversion)
There are three interconversion methods available:
• API 19875
• API 1994 Indirect6
• API 1994 Direct7
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4-44
Characterizing Assays
Corrections for Raw Lab Data Group
In this group, two correction methods are available for previously
uncorrected laboratory data:
4-44
Correction
Description
Apply Lab
Barometric
Pressure Correction
ASTM D86 data that is generated above sea level conditions
must be corrected for barometric pressure. If this is not done by
the laboratory, select the Yes radio button from the subgroup
and HYSYS performs the necessary corrections. Enter the
ambient laboratory barometric pressure in the Lab Barometric
Pressure field and HYSYS corrects your ASTM distillation data
to 1atm before applying the API Data Book conversions for
ASTM D86 to TBP distillation.
Apply ASTM D86
API Cracking
Correction
Note that API no longer recommends using this correction:
The ASTM cracking correction is designed to correct for the
effects of thermal cracking that occur during the laboratory
distillation. If this is not done by the laboratory, select the Yes
radio button, and HYSYS performs the necessary corrections.
This correction is only applied to ASTM D86 temperatures
greater than 485°F (250°C). Note that the API cracking
correction should not be applied to ASTM D86 distillations that
extend beyond 900°F (500°C), due to the exponential nature of
the correction.
HYSYS Oil Manager
4-45
Extrapolation Methods Group
HYSYS allows you to choose the extrapolation method used for the
different Assays (i.e., Distillation and the Molecular Weight, Density and
Viscosity property curves). There are three methods available:
Extrapolation
Method
Uses
For assays representing cuts (i.e., naphtha) or assays for
properties other than Boiling Temperature.
Least Squares
The Least Squares method is a lower order Lagrange method.
For this method, the last five input points are used to fit a
second order polynomial. If the curvature is negative, a straight
line is fit.
Probability
Use the Probability extrapolation method in cases when your
Boiling Temperature assay represents a full range crude and
the data is relatively flat. For instance, the data in the distillation
range of your assay (i.e., 10% to 70%) may be relatively
constant. Instead of linearly extending the curve to the IBP and
FBP, the Probability method only considers the steep rise from
the FBP.
Temperature
Lagrange
Known Part
of Curve
Extrapolated
Part
Assay%
This group also allows you to specify which end of the curve to apply the
extrapolation method. There are three choices available:
•
•
•
Upper end
Lower end
Both ends
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4-46
Characterizing Assays
4.5.3 Working Curves Tab
The third tab of the Assay view is the Working Curves tab. After the
Assay is calculated, you can view the Assay Working Curves:
Figure 4.21
Recall that the working curves are interpolated using either a third or
fourth order Lagrange polynomial fit of your input curve, while the
method used to extrapolate points outside your data depends on the
type of curve (Mass Density, Viscosity, Molecular Weight). You select the
method for the fit of your input curve: Least Squares, Lagrange or
Probability.
HYSYS always uses 50 points in the calculation of the working curves,
but the molar distribution varies depending on the data you provide. In
cases where there is a region with a steep gradient, HYSYS moves more
points to that region, but still uses 50 points.
4-46
HYSYS Oil Manager
4-47
4.5.4 Plots Tab
Following the Working Curves tab is the Plots tab, on which you can
view any of the input data curves in a graphical format.
The User Property option is
only available if a User
Property is created and a
User Curve is defined in the
Assay.
The Property drop-down list, shown above, displays the options
available for the y-axis of the plot. The Distillation option shows the
boiling temperature input according to the Assay Type chosen (i.e., TBP,
ASTM D86, etc.). The x-axis displays the Assay% on a basis consistent
with the format of your input.
An example of a distillation boiling point curve is shown in the figure
below. All of the entered data point pairs and the interpolated values are
drawn on the plot.
Figure 4.22
For details on the various
Graph Control options, refer to
Section 10.4 - Graph Control
of the User Guide.
To make changes to the appearance of the plot, object inspect the plot
area. From the menu that appears, select Graph Control.
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4-48
Characterizing Assays
4.5.5 Correlations Tab
The Correlations tab of the Assay property view is shown below:
Figure 4.23
The correlations tab consists of the following objects:
You can define new
correlations sets via the
Correlation tab, accessible
from the main Oil
Characterization view. See
Section 4.8.1 - Correlation
Tab.
You can change only the
name of the default set. If you
want to change any
correlations, you must create
a new correlation set.
4-48
Object
Description
Selected
Correlation Set
By default, this is Default Set (if you have changed the name of the
default set, that name is displayed). You can select another
correlation set from the Selected drop-down list, but first you must
define one on the Correlation tab of the Oil Characterization
property view.
Low and High
End
Temperature
This is the range for which the Correlations are applied. If you split
the range, then more than one temperature range is displayed. Note
that you can edit the temperature of defined splits for custom
Correlation Sets on this tab.
MW
The MW correlation is displayed. You cannot change the correlation
in this view; this can be done from the Correlation tab accessible
from the main Oil Characterization view or by clicking the Edit
button.
SG
The specific gravity (density) correlation is displayed. You cannot
change the correlation in this view; this can be done from the
Correlation tab accessible from the main Oil Characterization view
or by clicking the Edit button.
Tc, Pc, Acc.
Factor, Ideal H
The critical temperature, critical pressure, acentricity and Ideal
Enthalpy correlations are displayed. You cannot change correlations
on this tab; this can be done in the Correlation view accessible from
the main Oil Characterization view. To edit the Selected Correlation
Set from this tab, click the Edit button. This takes you to the
Correlation view.
HYSYS Oil Manager
Although a Correlation set
contains methods for all
properties, the Correlation tab,
as seen on the Assay and
Blend views, displays only the
properties appropriate to that
step in the Characterization
process.
4-49
Only the molecular weight and specific gravity correlations are required
in the calculation of the working curves. Note that the critical pressure,
critical temperature, acentricity, and ideal enthalpy correlations are also
displayed on the Assay property view, as these are applicable only in the
calculation of the hypocomponent properties.
If you supply molecular weight or density curves, then their respective
correlations are not required. Note that you do not have a choice of
correlations for calculating the viscosity curves.
4.5.6 User Curves Tab
See Light Ends Handling &
Bulk Fitting for details on the
Light Ends Handling & Bulk
Fitting Options button.
The User Curves tab of the Assay property view is shown below:
Figure 4.24
There are two elements to a
User Curve:
• The definition of how the
property value is
calculated for a stream
(mixing rule).
• The assay/property
value information that is
supplied for a given
assay.
The property definition (see
Section 4.7 - User Property
for details) is common to all
assays.
The available and selected User Properties are displayed in the left
portion of the view. Note that User Properties are defined on the User
Property tab of the Oil Characterization view.
After a User Property is defined, you can add it to the Assay by
highlighting it and selecting the Add button. To remove a User Property
from the current Assay, highlight it and select the Remove button.
Double-clicking on a User Property name in the selection list opens the
user property view as described in Section 4.7.2 - User Property View.
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4-50
Characterizing Assays
After adding a User Property, you can edit the User Curve Data:
User Curve Data
Description
Table Type
This is either Dependent or Independent. If you select
Dependent, the Assay Percents are automatically set to the
values you specified for the Boiling Temperature assay (Input
Data tab). Note that if the table type is Dependent and you
change the assay percents on this tab, this also changes the
assay percents in the Distillation boiling temperature matrix
and for any other dependent curve.
Bulk Value
Specify a Bulk Value. If you do not want to supply a bulk value
for the user property, ensure that this cell reads <empty> by
placing the cursor in that cell and pressing the DELETE key.
Extrapolation
Method
This field allows you to choose the extrapolation method used
for the selected user property in the current assay. The
available choices are:
• Least Squares
• Lagrange
• Probability
Apply To
This field allows you to choose which end of the curve to apply
the extrapolation method to. There are three choices available:
• Upper end
• Lower end
• Both ends
User Property Table
Provide the Assay percents and User Property Values in this
table. At least five pairs of data are required.
4.5.7 Notes Tab
HYSYS provides a tab where you can enter a description of the Assay for
your own future reference. This can also be accessed through the notes
manager.
4-50
HYSYS Oil Manager
4-51
4.6 Hypocomponent Generation
Note that for a highlighted
Blend, you can edit the name
and provide a description in
the Blend Information group.
The Cut/Blend tab of the Oil Characterization view is shown below:
Figure 4.25
The Available Blends are listed in the left portion of the view. The
following Blend manipulation buttons are available:
As described in the Oil
Characterization View section:
• The Clear All button is
used to delete all Oil
Characterization
information.
• The Calculate All button
re-calculates all Assay
and Blend information.
• The Oil Output
Settings... button allows
you to change IBP, FBP,
ASTM D86, and ASTM
D2887 interconversion
methods for output
related calculations.
Button
Description
View
Edit the currently highlighted Blend.
Add
Create a new Blend.
Delete
Erase the currently highlighted Blend. HYSYS does not prompt for
confirmation when deleting a Blend, so be careful when you are
using this command.
Clone
Create a new Blend with the same properties as the currently
highlighted Blend. HYSYS immediately opens a new Blend view.
In the following sections, each tab of the Blend property view (accessed
through the View or Add buttons) is described.
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4-52
Hypocomponent Generation
4.6.1 Data Tab
All Boiling Point information
supplied in an assay is
converted to TBP format.
The Cut/Blend characterization in HYSYS splits internal working curves
for one or more assays into hypocomponents. Once your assay
information is entered through the Assay view, you must Add a Blend
and transfer at least one Assay to the Oil Flow Information table to split
the TBP working curve(s) into discrete hypocomponent. The first tab of
the Blend view is shown below:
Figure 4.26
To view an Assay, double-click
on the Assay name, either in
the Available Assays list, or in
the Oil column of the Oil Flow
Information table.
There is no limitation to the
number of assays that can be
included in a single blend or to
the number of blends that can
contain a given assay. Each
blend is treated as a single oil
and does not share
hypocomponent with other
blends or oils.
Note also that you are allowed
to define a flowsheet stream
for each constituent assay in a
blend.
4-52
Assay Selection
A list of the available Assays is shown in the left portion of the view. You
can choose an assay by highlighting it and clicking the Add button. It is
removed from the Available Assays list and added to the Oil Flow
Information table, which displays the following information:
Oil Flow
Information
Description
Oil
The name of the Assay is displayed in this column.
Flow Units
You can select the Flow Basis (Mole, Mass or Liquid Volume) here.
Note that if you have several Assays, it is not necessary that they
have the same Flow Basis.
Flow Rate
Enter the flow rate; you can use any units (with the same basis);
they are converted to the default.
HYSYS Oil Manager
4-53
Note that you can remove an Assay from the Oil Flow Information table
by highlighting it and selecting the Remove button.
Bulk Data
The Bulk Data button becomes available when more than one assay is
present in the Oil Flow Information table.
Figure 4.27
HYSYS allows you to provide the following bulk data for a blend on the
Bulk Values view:
•
•
•
•
Molecular Weight
Mass Density
Watson (UOP) K
Viscosities at 2 temperatures
The Bulk Data feature is particularly useful for supplying the bulk
viscosities of the blend, if they are known.
Cut Ranges
When you re-cut an oil,
HYSYS will automatically
update the associated
flowsheet streams with the
new hypocomponents when
you leave the Basis
Environment.
You have three choices for the Cut Option Selection:
Cut Options
Description
Auto Cut
HYSYS cuts the assay based on internal values.
User Ranges
You specify the boiling point ranges and number of cuts per range.
User Points
You specify only how many hypocomponent you require. HYSYS
proportions the cuts according to an internal weighting scheme.
These methods are described in detail later in this section.
4-53
4-54
Hypocomponent Generation
You can specify as many components as you want, within the
limitations of the available memory. Whether specified or calculated
internally, each cut point is integrated to determine the average
(centroid) boiling point. The centroid is always determined using
HYSYS’ internally generated TBP curve on a weight basis.
Although the external procedure for blending assays is almost identical
with that for cutting a single assay, HYSYS’ internal procedure is
somewhat different. After HYSYS has converted each assay to a TBP vs.
weight percent curve, all of the individual curves are combined to
produce a single composite TBP curve. This composite curve is then
used as if it were associated with a single assay; hypocomponents are
generated based on your instructions.
These hypocomponents are now common to the blended oil and all the
constituent oils. For each of the constituent oils, HYSYS back calculates
the compositions that correspond to these hypocomponents.
Caution should be exercised when blending some combinations of
analyzes. An inherent advantage, as well as limitation, of blending is
that all constituent oils share a common set of hypocomponent and
therefore physical property characteristics. Any analyzes that have large
overlapping TBP curves and very different physical property curves
should not be blended (for example, hydrocracker recycles and
feedstocks have similar TBPs but very different gravity curves). The
physical properties of components for overlapping areas represent an
average that may not represent either of the constituent assays.
HYSYS allows you to assign
the overall blend composition
and/or individual assay
compositions to streams via
the Install Oil tab (Section
4.8.3 - Install Oil Tab).
This procedure is recommended whenever recombining product oils or
fractions to produce a single inlet stream, for example in generating a
feed for an FCCU main fractionator from analyzes of the product
streams. The major advantage to blending is that fewer
hypocomponents are used to represent a given feed because duplicate
components for overlapping TBP curves are eliminated.
A second advantage is that the composite TBP curve tends to smooth
the end portions of the individual assay curves where they may not be as
accurate as the middle portions of the curves.
4-54
HYSYS Oil Manager
4-55
Recommended Boiling Point Widths
The following table is a guideline for determining the number of splits
for each boiling point range. These are based upon typical refinery
operations and should provide sufficient accuracy for most
applications. You may want to increase the number of splits for ranges
where more detailed fractionation is required.
Cutpoint Range
Boiling Point Width
Cuts/100°F
IBP to 800°F (425°C)
25°F (15°C) per cut
4
800°F to 1200°F (650°C)
50°F (30°C) per cut
2
1200°F to 1650°F (900°C)
100°F (55°C) per cut
1
Regardless of your input data, it is recommended that you limit your
upper boiling range to 1650°F (900°C). All of the critical property
correlations are based on specific gravity and normal boiling points and
thus, NBPs above this limit may produce erroneous results. The critical
pressure correlations control this limit. There is no loss in accuracy by
lumping the heavy ends because incremental changes in solubility of
lighter components are negligible and this range is generally not be
fractionated.
Auto Cut
If you select the AutoCut option, HYSYS performs the cutting
automatically. HYSYS uses the boiling point width guidelines, as shown
previously:
Range
Cuts
100 - 800°F
28
800 - 1200°F
8
1200 - 1600°F
4
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4-56
Hypocomponent Generation
User Points
If you select User Points from the Cut Option Selection drop-down list,
HYSYS performs the cutting process depending on the number of cuts
you specify. Enter the total number of cuts you want to use for the oil in
the appropriate field. All splits are based upon TBP temperature,
independent of the source or type of assay data. HYSYS proportions the
cuts according to the following table:
Cutpoint Range
Internal Weighting
IBP - 800°F (425°C)
4 per 100°F
800°F - 1200°F (650°C)
2 per 100°F
1200°F to FBP
1 per 100°F
The internal weighting produces more hypocomponents per 100°F
range at the lower boiling point end of the assay. For example, given a
TBP temperature range of 100°F to 1400°F and 38 components
requested, HYSYS produces 28 components for the first range, eight
components for the second range and two components for the last
range:
(800 - 100) / 100 * 4 = 28
(1200 - 800) / 100 * 2 = 8
(1400 - 1200) / 100 * 1 = 2
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HYSYS Oil Manager
4-57
User Ranges
If you want to define cutpoint ranges and specify the number of
hypocomponent in each range, select User Ranges and HYSYS displays
the Ranges Selection information as shown in the figure below.
Figure 4.28
The IBP and FBP are shown above and these values correspond to the
initial boiling point and the final boiling point of HYSYS’ internal TBP
working curve. At this point all light ends are removed (if requested) and
the IBP presented is on a light ends free basis. Refer to the Boiling
Ranges Section 4.4 - Oil Characterization View for definitions of the IBP
and FBP.
Note that the IBP and FBP of the internal TBP curve used for the column
operation’s cutpoint specifications and the boiling point tables are
determined in this manner. If the first or last hypocomponent has a
volume fraction larger than that defined by the endpoints for the IBP or
FBP respectively, the TBP curve is extrapolated using a spline fit.
You may supply the Initial Cut Point; however, if this field is left blank,
HYSYS uses the IBP. HYSYS combines the material boiling between the
IBP and the initial cutpoint temperature with the material from the first
cut to produce the first component. This component has an NBP
centroid approximately half way between these boundaries.
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4-58
Hypocomponent Generation
The next parameters that you must supply are the upper cutpoint
temperature and the number of cuts for the first cutpoint range. As
shown in Figure 4.28, the upper cutpoint temperature for the first range
also corresponds to the lower boiling point of the second cutpoint
range, so it does not have to be re-entered. After the first cut range is
defined, only the upper cutpoint temperature and the number of cuts
need to be supplied for the remaining ranges. If the final cutpoint
temperature is not equal to or greater than the FBP, HYSYS combines
the material between the FBP and the last cut temperature with the
material in the last component.
For example, assume that the IBP and FBP are 40 and 1050°F
respectively, the initial cut temperature is 100, the upper limit for the
first cut is 500 degrees, and the number of cuts in the first range is eight.
Since the boiling width for each component in the first cut range is 50°F
(i.e., [500-100]/8), the first component's NBP is at the centroid volume
of the 40 to 150 cut, in this case approximately 95°F. The remaining
components have NBP values of approximately 175, 225, 275, 325, 375,
425 and 475°F. The upper temperature for the second range is 1,000 and
the number of cuts is equal to 5. Since the FBP is 1050, the material in
the boiling range from 1,000 to 1,050 is included with the last
component.
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HYSYS Oil Manager
4-59
4.6.2 Correlations Tab
The Correlations tab of the Blend property view is shown in the figure
below:
Figure 4.29
As in the Assay Oil
characterization, you can
only change the name of the
default set. If you want to
change any correlations, you
must create a new
correlation set.
The Correlations tab consists of the following objects:
You can define new
correlations sets via the
Correlation tab, accessible
from the main Oil
Characterization view. See
Section 4.8.1 - Correlation
Tab.
You can change only the
name of the default set. If you
want to change any
correlations, you must create
a new correlation set.
Object
Description
Selected
Correlation Set
By default, this is Default Set (if you have changed the name of the
default set, that name is displayed). You can select another
correlation set from the Selected drop-down list, but first you must
define one on the Correlation tab of the Oil Characterization
property view.
Low and High
End
Temperature
This is the range for which the Correlations are applied. If you split
the range, then more than one temperature range is displayed. Note
that you can edit the temperature of defined splits for custom
Correlation Sets on this tab.
MW
The MW correlation is displayed. You cannot change the correlation
in this view; this can be done from the Correlation tab accessible
from the main Oil Characterization view or by clicking the Edit
button.
SG
The specific gravity (density) correlation is displayed. You cannot
change the correlation in this view; this can be done from the
Correlation tab accessible from the main Oil Characterization view
or by clicking the Edit button.
Tc, Pc, Acc.
Factor, Ideal H
The critical temperature, critical pressure, acentricity and Ideal
Enthalpy correlations are displayed. You cannot change correlations
on this tab; this can be done in the Correlation view accessible from
the main Oil Characterization view. To edit the Selected Correlation
Set from this tab, click the Edit button. This takes you to the
Correlation view.
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4-60
Hypocomponent Generation
The critical pressure, critical temperature, acentricity and ideal
enthalpy correlations are required in the Blend calculation (or more
specifically, in the calculation of hypocomponent properties). In the
calculation of hypocomponent properties, the molecular weight and
specific gravity (and viscosity) are estimated from their respective
working curves.
4.6.3 Tables Tab
After calculating a Blend, you can examine various property and flow
summaries for the generated hypocomponent that represent a
calculated oil.
Figure 4.30
From the Table Type drop-down list, you can select any one of the
following:
4-60
Table Type
Description
Component Properties
With this Table Type selection, you can select one of the
two radio buttons in the Table Control group:
• Main Properties. Provides the normal boiling point,
molecular weight, density and viscosity information
for each individual component in the oil.
• Other Properties. Provides the critical temperature,
critical pressure, acentric factor and Watson K factor
for each individual hypocomponent.
Component Breakdown
Provides individual liquid volume%, cumulative liquid
volume%, volume flows, mass flows and mole flows, for
the input light ends and each hypocomponent in the oil.
HYSYS Oil Manager
Table Type
Description
Molar Compositions
Provides the molar fraction of each light end component
and each hypocomponent in the oil.
Oil Properties
For this selection, you can select the Basis (liquid volume,
molar or mass) in the Table Control group box. There are
also three radio buttons, each producing a different table:
• Distillation. Provides TBP, ASTM D86, D86 Crack
Reduced, ASTM D1160 (Vac), ASTM D1160 (Atm),
and ASTM D2887 temperature ranges for the oil.
• Other Properties. Provides critical temperature,
critical pressure, acentric factor, molecular weight,
density and viscosity ranges for the oil.
• User Properties. Provides all user property ranges
for the oil.
Oil Distributions
Provides tabular information on how your assay would be
roughly distributed in a fractionation column. Examine the
End Temperatures of the various ranges as well as the
Cut Distributions. You can select the basis for the Cut
Distribution Fractions (Liquid Volume, Molar, Mass) in the
Table Control group. The radio buttons provide the option
of standard fractionation cuts or user defined cuts:
• Straight Run. Lists crude column cuts: Off gas,
LSR Naphtha, Naphtha, Kerosene, Light Diesel,
Heavy Diesel, Atmos Gas Oil and Residue.
• Cycle Oil. Lists Cat Cracker cycle oils: Off Gas, LC
Naphtha, HC Naphtha, LCGO, ICGO, HCGO,
Residue 1 and Residue 2.
• Vacuum Oil. Lists vacuum column cuts: Off Gas,
LVGO, HVGO and 5 VAC Residue ranges.
• User Custom. Allows for the definition of
customized temperature ranges. If changes are
made to the information in any of the standard
fractionation cuts, the radio button will automatically
switch to User Custom.
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4.6.4 Property Plot Tab
HYSYS can plot various properties versus liquid volume, mole or mass
percent distilled. The x-axis choice is made from the Basis drop-down
list. Any of the following options may be plotted on the y-axis by making
a selection from the Property drop-down list:
•
•
•
•
•
Distillation. A table appears in which you can select which boiling
point curves to examine. Activate the checkbox of each curve you
want displayed. The options include: TBP, ASTM D86,
D86(Crack Reduced), ASTM D1160(Vac), ASTM D1160(Atm)
and ASTM D2887.
Molecular Weight
Density
Viscosities at 100 and 210°F (or the input temperature)
Critical Temperature
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4-62
Hypocomponent Generation
•
•
•
Critical Pressure
Acentric Factor
User Property. A table appears to allow you the choice of which
user property to plot.
Refer to the Section 4.6.7 Plot Summary Tab section
for information concerning the
Plot Summary tab.
Click the Clone and shelf this plot button to store the current plot.
HYSYS automatically names the plot with the following format: ’the
name of the active blend’-’number of plots created’. For instance, the
first plot created for Blend-1 would be named Blend-1-0, and any
subsequent plots would have the number after the dash incrementally
increased.
Plot labels can not be modified
within the Property Plot tab
Blend view.
To edit plot labels, you must clone the plot using the Clone and shelf this
plot button. The BlendPlot appears and is stored in the Plot Summary
tab.
An example of a TBP curve on a liquid volume basis for an oil is shown
below.
Figure 4.31
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HYSYS Oil Manager
4-63
4.6.5 Distribution Plot Tab
HYSYS can also plot a distribution bar chart so you can study how your
assay would be roughly distributed in a fractionation column. Straight
Run, Cycle Oil, Vacuum Oil and User Custom TBP cutpoints are
available distribution options, as shown by the radio buttons in the Cut
Input Information group. You can choose the Basis for the Cut
Distribution Fractions (Liquid Volume, Molar, Mass) in the Plot Control
group.
Figure 4.32
Click the Clone and shelf this plot button to store the current plot.
HYSYS automatically names the plot with the following format: ‘the
name of the active blend'-'number of plots created'.
Refer to the Section 4.6.7 Plot Summary Tab for
information concerning the
Plot Summary tab.
Plot labels can not be modified
within the Distribution tab
Blend view.
For example, the first plot created for Blend-1 is named Blend-1-0, and
any subsequent plots would have the number after the dash
incrementally increased. All stored plots are listed on the Plot Summary
tab.
To edit plot labels, you must clone the plot using the Clone and shelf this
plot button. The BlendPlot appears and is stored in the Plot Summary
tab.
If changes are made to the names or end temperatures in any of the
standard fractionation cuts, the radio button automatically switches to
User Custom.
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4-64
Hypocomponent Generation
An example distribution plot is shown in the following figure.
Figure 4.33
4.6.6 Composite Plot Tab
The Composite Plot tab allows you to visually check the match between
the input assay data and the calculated property curves. The choice for
the graphical comparison is made from the Property drop-down list:
•
•
•
•
•
Distillation
Molecular Weight
Density
Viscosity
User Property
Click the Clone and shelf this plot button to store the current plot.
HYSYS automatically names the plot with the following format: ’the
name of the active blend’-’number of plots created’.
Refer to the Section 4.6.7 Plot Summary Tab for
information concerning the
Plot Summary tab.
For example, the first plot created for Blend-1 is named Blend-1-0, and
any subsequent plots have the number after the dash incrementally
increased. All stored plots are listed on the Plot Summary tab.
Plot labels can not be modified
within the Composite tab
Blend view.
To edit plot labels, you must clone the plot using the Clone and shelf
this plot button. The BlendPlot appears and is stored in the Plot
Summary tab.
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HYSYS Oil Manager
4-65
An example molecular weight curve comparison is shown in the
following figure.
Figure 4.34
The calculated molecular weight lies above the input curve (instead of
over-laying it) because the calculated curve has been shifted to match
an input bulk MW.
4.6.7 Plot Summary Tab
On this tab, you can view the list of stored plots for the current blend.
From the Created Plots group you can access any stored plots or remove
plots from the list. The list of created plots are generated from the
Property, Distribution, and Composite Plots tabs and shown below.
Access a plot by double-clicking on its name or by object inspecting its
name and selecting View from the menu. From the BlendPlot view, you
can edit plot labels by right-clicking and selecting the graph control
option. This method of modifying plots is preferable, since you can plot
what you want and that there is a single location for viewing them.
The cloned plots are independent, thus the labels can be modified and
are not overwritten. The plotted data for the cloned plots is also updated
as the blend changes.
There is no confirmation
message when you click the
Remove button.
Click the Remove button to remove a selected plot from the list. Only
one plot can be removed from the list at a time.
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4-66
User Property
4.6.8 Notes Tab
HYSYS provides a tab where you can enter a description of the Blend for
your own future reference.
4.7 User Property
A User Property is any property that can be defined and subsequently
calculated on the basis of compositions. Examples for oils include
R.O.N. and Sulfur content. During the characterization process, all
hypocomponents are assigned an appropriate property value. HYSYS
then calculates the value of the property for any flowsheet stream. This
enables User Properties to be used as Column specifications.
Refer to Section 4.5.6 - User
Curves Tab for an
explanation of attaching User
Properties to existing Assays.
After User Properties are installed, you can then supply assay
information as for Viscosity, Density or Molecular Weight Curves.
4.7.1 User Property Tab
The User Property tab of the Oil Characterization property view is
shown below:
Figure 4.35
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HYSYS Oil Manager
As described in the Oil
Characterization View section:
• The Clear All button is
used to delete all Oil
Characterization
Information.
• The Calculate All
button re-calculates all
Assay and Blend
information.
• The Oil Output
Settings... button allows
you to change IBP, FBP,
ASTM D86, and ASTM
D2887 interconversion
methods for output
related calculations.
4-67
The Available User Properties are listed in the left portion of the view.
The following User Property manipulation buttons are available:
Button
Description
View
Edit the currently highlighted User Property.
Add
Create a new User Property (see the following section, User
Property View).
Delete
Erase the currently highlighted User Property. HYSYS does not
prompt for confirmation when deleting a User Property.
Clone
Create a new User Property with the same properties as the
currently highlighted User Property. HYSYS immediately opens a
new User Property view (see the following section, User Property
View).
Note that for a highlighted User Property, you can edit the name and
provide a description.
4.7.2 User Property View
Refer to Chapter 7 - User
Properties for detailed
information on User Properties.
When you first open this view, the Name field has focus. The name of
the User Property must be 12 characters or less.
Figure 4.36
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4-68
User Property
Equation Parameters
The following options are available for the Basic user prop definition
group:
Parameter
Description
Note that the choice of Mixing
Basis applies only to the
basis that is used for
calculating the property in a
stream. You supply the
property curve information on
the same basis as the Boiling
Point Curve for your assay.
Mixing Basis
You have the following options: Mole Fraction, Mass Fraction,
Liquid Volume Fraction, Mole Flow, Mass Flow, and Liquid
Volume Flow.
Refer to Chapter 7 - User
Properties for more detail on
the Mixing Rules.
Mixing Rule
Note that all calculations are performed using compositions in
HYSYS internal units. If you have specified a flow basis (molar,
mass or liquid volume flow), HYSYS uses the composition as
calculated in internal units for that basis. For example, a User
Property with a Mixing Basis specified as molar flow is always
calculated using compositions in kg mole/s, regardless of what
the current default units are.
Select from one of three mixing rules:
( P mix )
f1
N
= f 2 ∑ ( x ( i )P ( i ) )
f1
i=1
( P mix )
f1
N
= f 2 ∑ ( x ( i ) ln ( P ( i ) ) )
f1
i=1
f1 • P mix + 10
f2 • P mix
=
N
∑ x ( i ) ( f1 • P ( i ) + 10
f2 • P ( i )
)
i=1
where:
Pmix = total user property value
P(i) = input property value for component
x(i) = component fraction or flow, depending on the
chosen Mixing Basis
f1 and f2 are specified constants
4-68
Mixing Parameters
The mixing parameters f1 and f2 are 1.00 by default. You may
supply any value for these parameters.
Unit Type
This option allows you to select the variable type for the user
property. For example, if you have a temperature user property,
select temperature in the unit type using the drop-down list.
HYSYS Oil Manager
4-69
Component User Property Values
Once you have calculated a
Blend which includes an
Assay with your User Property
information, the value of the
User Property for each
hypocomponent is displayed
in the Component User
Property Values group.
If you want, you may provide a Property value for all of the Light End
components you defined in the Property Package. This is used when
calculating the property value for each hypocomponent (removing that
portion of the property curve attributable to the Light Ends
components).
On this view, you do not provide property curve information. The
purpose of this view is to instruct HYSYS how the User Property should
be calculated in all flowsheet streams. Whenever the value of a User
Property is requested for a stream, HYSYS uses the composition in the
specified basis, and calculate the property value using your mixing rule
and parameters.
Notes Tab
HYSYS provides a tab where you can enter a description of the User
Properties for your own future reference.
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4-70
Correlations & Installation
4.8 Correlations & Installation
4.8.1 Correlation Tab
Correlation sets can also be
viewed through the Assay tab
- Correlations and Cut/
Blend tab - Correlations tab.
HYSYS allows you to choose from a wide variety of correlations to
determine the properties of the generated hypocomponent. From the
Correlation tab of the Oil Characterization view, you can create
customized Correlation Sets.
Figure 4.37
As described in the Oil
Characterization View
section:
• The Clear All button is
used to delete all Oil
Characterization
Information.
• The Calculate All
button re-calculates all
Assay and Blend
information.
• The Oil Output
Settings... button
allows you to change
IBP, FBP, ASTM D86,
and ASTM D2887
interconversion
methods for output
related calculations.
4-70
The Available Correlation Sets are listed on the left side of the view. The
following Correlation manipulation buttons are available:
Buttons
Description
View
Edit the currently highlighted Correlation Set.
Add
Create a new Correlation Set (see the following section, Correlation
Set View).
Delete
Erase the currently highlighted Correlation Set. HYSYS does not
prompt for confirmation when deleting a Correlation Set.
Clone
Create a new Correlation Set with the same properties as the
currently highlighted Correlation Set. HYSYS immediately opens a
new Correlation Set view (see Correlation Set View).
Note that for a highlighted Correlation Set, you can edit the name and
provide a description.
HYSYS Oil Manager
4-71
4.8.2 Correlation Set View
When you create or edit a Correlation Set, the following view appears:
Figure 4.38
When you first open this view, the Name field has focus. The name of
the Correlation Set must be 12 characters or less.
• The Working Curves are
calculated from the Assay
data, incorporating the
Molecular Weight and
Specific Gravity
correlations.
• The Hypocomponents are
generated based on your
cut option selections.
• Finally, the
hypocomponent
properties are generated:
• The NBP, molecular
weight, density and
viscosity are determined
from the Working curves.
• The remaining properties
are calculated,
incorporating the critical
temperature, critical
pressure, acentric factor
and heat capacity
correlations.
Correlations and Range Control
Changes to the Molecular Weight or Specific Gravity correlations are
applied to the curve (Assay), while the critical temperature, critical
pressure, acentric factor and heat capacity correlations apply to the
Blend’s hypocomponent properties. Note that changes to the Assay
correlations have no effect when you have supplied a property curve
(e.g., Molecular Weight); they only apply in the situation where HYSYS is
estimating the properties.
To change a correlation, position the cursor in the appropriate column
and select a new correlation from the drop-down list.
You cannot change the correlations or range for the Default Correlation
Set. If you want to specify different correlations or temperature ranges,
you must create a new Correlation Set.
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4-72
Correlations & Installation
The table below shows the HYSYS defaults and available options for
these properties.
Property
Default Correlation
MW
Twu
Optional Correlations
•
•
•
•
•
•
•
•
•
•
•
•
Lee-Kesler
Aspen
Penn State
KatzFiroozabadi
Hariu-Sage
API
Robinson-Peng
Whitson
Rowe
Standing
Lyderson
Penn State
Mathur
Twu
•
•
•
•
•
Cavett
Riazi-Daubert
Edmister
Bergman
Aspen
Cavett
Riazi-Daubert
Edmister
Bergman
Aspen
Roess
Eaton-Porter
Twu
Riazi-Daubert
Bergman
Katz-Nokay
Modified KeslerLee
• Aspen leastsquares
• Twu
Pc
Lee-Kesler
•
•
•
•
•
•
Tc
Lee-Kesler
•
•
•
•
•
•
Rowe
Standing
Nokay
Penn State
Mathur
SpencerDaubert
• Chen-Hu
• MeissnerRedding
•
•
•
•
•
•
•
•
SG
Constant Watson K
• Bergman
• Yarborough
• Lee-Kesler
• Bergman-PNA
• Hariu-Sage
• KatzFiroozabadi
Ideal
Enthalpy
Lee-Kesler
• Cavett
• Modified LeeKesler
• Fallon-Watson
Acentric
Factor
Lee-Kesler
• Edmister
• Robinson Peng
• Bergman
The Riazi-Daubert correlation has been modified by Whitson. The
Standing correlation has been modified by Mathews-Roland-Katz. The
default correlations are typically the best for normal hydrocarbon
systems. An upper limit of 1250°F (675°C) is suggested for the heaviest
component. Although the equations have been modified to extend
beyond this range, some caution should be exercised when using them
for very heavy systems. Highly aromatic systems may show better
results with the Aspen correlations. Detailed discussions including the
range of applicability for the correlations is found in
Appendix B - Petroleum Methods/Correlations.
4-72
HYSYS Oil Manager
4-73
You have the choice of changing a property correlation over the entire
range, or making a certain correlation valid for a particular boiling point
range only. To split correlations over several boiling ranges click the Add
New Range button and the following view appears.
Enter the temperature where you want to make the split into the New
Temp cell (in this case 400 °C), and select the Split Range button. The
temperature is placed in the correlation set, and the Correlation table is
split as shown below:
Figure 4.39
When you merge a range, you
delete the correlations for the
range whose Low End
Temperature is equal to the
range temperature you are
merging.
You can now specify correlations in these two ranges. If you want, you
may add more splits; or you can also delete a split (merge range) by
selecting the Remove Range button as shown in Figure 4.39.
Highlighting the appropriate temperature in the Temperature Range list
and selecting the Merge Temp Range button removes or merges the
temperature range. When you merge a range, any correlations you
chose for that range is forgotten.
Any changes to the correlations for an Input Assay results in first the
assay being recalculated, followed by any blend which uses that assay.
For an existing oil, it will be automatically recalculated/re-cut using the
new correlations, and the new components are installed in the
flowsheet.
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4-74
Correlations & Installation
Assay & Blend Association
The different components of the Assay and Blend Association group are
described below:
Object
Description
New Assays/Blends
If you check this, all new Assays and Blends that are created
use this Correlation Set.
Available Assays/
Available Blends
These radio buttons toggle between Assay or Blend
information.
Assay/Blend Table
This table lists all Assays or Blends with their associated
Correlation Sets, depending on which radio button is selected.
You can check the Use this Set checkbox to associate the
current Correlation Set with that Assay or Blend. Note that you
can also select the Correlation Set for a specific Assay on the
Correlation tab of that Assay view.
Notes Tab
HYSYS provides a tab where you can enter a description of the
Correlations for your own future reference.
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HYSYS Oil Manager
4-75
4.8.3 Install Oil Tab
The Install Oil tab of the Oil Characterization property view is shown
below:
Figure 4.40
If you want to install the
hypocomponent into a nonAssociated Fluid Package, Add
the Oil Hypo group from the
Components tab of that Fluid
Package view.
You may install a calculated Blend into your HYSYS case; it appears in
the Oil Name column of the table. Simply provide a Stream name for
that Blend, and ensure that the Install box is checked. You may use an
existing stream name, or create a new one. If you do not provide a name
or you deactivate the Install box(es), the hypocomponent is not
attached to the fluid package. You can install an oil to a specific
subflowsheet in your case by specifying this in the Flow Sheet column.
Each installed Oil appears in the component list as a series of
hypocomponents named NBP[1] ***, NBP[2] ***, with the 1 representing
the first oil installed, 2 the second, etc.; and *** the average boiling point
of the individual Oil components. HYSYS also assigns the Light Ends
composition, if present, in the flowsheet stream.
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4-76
TBP Assay - Example
For Blends that contain more
than one Assay - each individual
Assay is automatically displayed
in the Oil Install Information table.
When a Blend is installed in a stream, the relative flow rate of each
constituent Assay is defined within the Oil Characterization and cannot
be changed. However, if you install each of the constituent Assays
(represented by Blends with a single Assay) into their own flowsheet
stream, various combinations can be examined using Mixer or Mole
Balance operations. The flow and composition for each constituent oil
is transferred to your designated flowsheet streams. The flow rate of any
specified Oil stream (as opposed to the constituents of a Blend) can be
changed at any time by re-specifying the stream rate in the flowsheet
section.
4.9 TBP Assay - Example
In this example, a crude oil with a TBP assay curve extending from 100°F
to 1410°F is characterized. Associated with this TBP assay are:
•
•
•
•
•
A dependent molecular weight curve
An independent API gravity curve
Two independent viscosity curves, one at 100°F and the other at
210°F
The bulk molecular weight and bulk API gravity
A liquid volume Light Ends assay for the crude oil
It is desired to split the assay into 38 hypocomponents, with 25°F cuts
between 100 and 800°F, 50°F cuts between 800 and 1200°F, and the
remaining portion of the crude assay into two components.
The following assay information is available:
Bulk Crude Properties
MW
300
API Gravity
48.75
Light Ends Liquid Volume%
4-76
Propane
0.0
i-Butane
0.19
n-Butane
0.11
i-Pentane
0.37
n-Pentane
0.46
HYSYS Oil Manager
4-77
TBP Distillation Assay
Dependent property curves
have values at the same
distillation percentage as the
Boiling Temperature assay,
but does not need to have
values at every percentage.
Liquid Volume%
Temperature (F)
0.0
80.0
Molecular Weight
68.0
10.0
255.0
119.0
20.0
349.0
150.0
30.0
430.0
182.0
40.0
527.0
225.0
50.0
635.0
282.0
60.0
751.0
350.0
70.0
915.0
456.0
80.0
1095.0
585.0
90.0
1277.0
713.0
98.0
1410.0
838.0
API Gravity Assay
Liq Vol% Distilled
API Gravity
13.0
63.28
33.0
54.86
57.0
45.91
74.0
38.21
91.0
26.01
Viscosity Assay
Liq Vol% Distilled
Visc. (cP) 100°F
10.0
0.20
Visc. (cP) 210°F
0.10
30.0
0.75
0.30
50.0
4.20
0.80
70.0
39.00
7.50
90.0
600.00
122.30
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4-78
TBP Assay - Example
4.9.1 Initialization
Refer to Chapter 2 - Fluid
Package for details on
installing a fluid package.
Oil Environment icon
Refer to the Section 12.3.1 Units Page of the User
Guide for details on creating
a customized unit set.
For more information
concerning the Trace
Window, refer to Section 1.3
- Object Status Window/
Trace Window of the User
Guide.
4-78
Before you can start the actual characterization process, you must:
1.
Begin a new HYSYS case.
2.
Select an appropriate property package.
3.
Add any non-oil components, including the Light Ends that are to
be used in the characterization process, to the component list.
In this case, use the Peng-Robinson equation of state, and select the
following components: C3, i-C4, n-C4, i-C5, and n-C5. After you have
selected the Light End components, click the Oil Environment icon on
the toolbar to enter the Oil Characterization environment.
Prior to the input of assay data, a customized Unit Set is created such
that the default units used by HYSYS correspond to the assay data units.
Create a customized unit set by cloning the Field unit set. Select API as
the new unit for both Mass Density and Standard Density and leave all
other Field default units as they are.
You can view a display of important messages related to the progress of
the characterization in the Trace Window. If you want, open the Trace
Window at the bottom of the Desktop.
HYSYS Oil Manager
4-79
The main view in the Oil Environment is the Oil Characterization
property view, as shown below:
Figure 4.41
These three steps are the
minimum requirements in
defining and installing an oil.
The tabs are organized according to the general procedure followed in
the characterization of an oil. Completing the characterization requires
three steps:
1.
Access the Assay view by selecting the Add button on the Assay tab
of the Oil Characterization view. Input all of the assay data on the
Input Data tab of the Assay view and click the Calculate button.
2.
Access the Cut/Blend view (which also gives you cutting options) by
selecting the Add button on the Cut/Blend tab of the Oil
Characterization property view. Cut the assay into the required
number of hypocomponent using the cut points outlined
previously.
3.
Install the calculated oil from the Oil Environment into the
flowsheet by accessing the Install Oil tab of the Oil Characterization
property view.
Although you can access the User Property tab and the Correlation tab
from the Oil Characterization view, neither of these tabs are used in this
example.
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4-80
TBP Assay - Example
4.9.2 Step 1 - Input Assay Data
On the Assay tab of the Oil Characterization view, select the Add button.
This opens the Assay view and places the active location in the Name
cell of the Input Data tab. For this example, change the name of the
Assay to Example. The Assay tab is shown below. Note that the first time
you enter this view, it is blank, except for the Bulk Properties field and
the Assay Data Type field.
Figure 4.42
The layout of this view depends
on:
1. Which Data Type you have
selected. This mainly affects
what Data Type options are
available (Distillation, Light
Ends, etc.)
2. Which Input Data radio
button you have selected. When
you specify that you have
Independent or Dependent
Molecular Weight, Density or
Viscosity data, a new radio
button is added to the view. In
this view, the TBP Data Type is
selected and the Distillation
radio button is selected.
4-80
HYSYS Oil Manager
4-81
Defining the Assay
The Input Data tab is split into two groups: Assay Definition and Input
Data. As its name implies, the Assay Definition group is where the
properties of the assay are defined. Since bulk property data is provided,
select Used from the Bulk Properties drop-down list. The bulk
properties appears in the Input Data group. Next from the Assay Data
Type drop-down list, select TBP. The Bulk Props and Distillation radio
buttons are now visible.
Light ends can be Auto Calculated by HYSYS, however since you are
provided with the light ends data, select Input Compositions from the
Light Ends drop-down list.
Now, set the Molecular Weight, Density and Viscosity curve options in
each of the respective drop-down lists. The Molecular Weight curve is
Dependent, the Density curve is Independent, and the Viscosity curves
are also Independent. As you specify these options, radio buttons
corresponding to each curve are added to the Input Data group box.
Now that the Assay is sufficiently defined, you can begin entering assay
data.
Specifying Assay Data
Specification of the Assay occurs in the Input Data group. The field and
options visible inside the group are dependent on which radio button is
selected in the Input Data group.
HYSYS calculates internal working curves using the supplied property
curve data. For each property curve, you can select the method used for
the Extrapolation of the working curve. The Extrapolation method for
each working curve is specified in the Curve Fitting Methods group of
the Calculation Defaults tab.
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4-82
TBP Assay - Example
Bulk Props
Select the Bulk Props radio button. Input a Bulk Molecular Weight (300)
and Bulk Mass Density (48.75 API_60) as shown in the figure below. No
bulk viscosity information is available, so leave the Viscosity cells blank.
It is not necessary to delete the Viscosity Temperatures as these are
ignored if you do not provide bulk viscosities.
Light Ends
Next, select the Light Ends radio button. The Input Data group displays
a Light Ends Basis drop-down list and a Light Ends Composition table.
From the drop-down list, select LiquidVolume as the Light Ends Basis
and enter the Light Ends composition as shown below:
Figure 4.43
4-82
HYSYS Oil Manager
4-83
Distillation
As you enter values into the
table, the cursor automatically
moves down after each entry,
making it easier to supply all
values in each column.
Select the Distillation radio button to view the TBP Distillation assay. To
enter the data, click the Edit Assay button. The Assay Input Table view
appears and enter the following assay data:
Figure 4.44
Molecular Weight
Select the Molecular Weight radio button to view the Molecular Weight
data. Since the Molecular Weight assay is Dependent, the Assay
Percentage values that you entered for the Boiling Point Temperature
assay are automatically displayed. You need only enter the Molecular
Weights as shown below:
Figure 4.45
4-83
4-84
TBP Assay - Example
Density
Select the Density radio button to view (or edit) the Density assay. The
default density units are displayed, in this case API. The completed API
gravity curve input is shown below:
Figure 4.46
Viscosity
Ensure that the Viscosity
Units Type is Dynamic, and
that the two temperatures
entered are 100°F and 210°F.
Select the Viscosity1 and Viscosity2 radio buttons to view (or edit) the
Viscosity assays. When either of these buttons are selected, an
additional input box is displayed, which allows you to supply the
viscosity temperatures. Make sure the Use Both radio button is selected
in the Viscosity Curves group box. The required viscosity input is shown
below:
Figure 4.47
4-84
HYSYS Oil Manager
4-85
Calculating the Assay
After entering all of the data, go to the Calculation Defaults tab. Note the
extrapolation methods displayed in the Curve Fitting Methods group.
Figure 4.48
The default extrapolation methods for the working curves are adequate
for this assay. To begin the calculation of the assay, press the Calculate
button. The status message at the bottom of the Assay view shows the
message Assay Was Calculated.
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4-86
Refer to Section 4.5 Characterizing Assays for
information on the
characterization procedure,
working curves and
extrapolation methods.
TBP Assay - Example
After the Assay is calculated, the working curves are displayed on the
Working Curves tab.
Figure 4.49
The working curves for the normal boiling point, molecular weight,
mass density and viscosity are regressed from your input curves. HYSYS
uses 50 points in the calculation of the working curves, but the molar
distribution varies depending on the data you provide. HYSYS moves
more points to a region with a steep gradient. The calculation of the
Blend is based on these working curves.
The options available in the
Property drop-down list
correspond to the property
curve data specified on the
Input Data tab. If only bulk
data is provided, there are no
plots available.
4-86
You can examine graphical representations of your assay data on the
Plots tab. Open the Property drop-down list and select the curve that
you would like to view. The default plot is the Boiling Point Temperature
(Distillation) curve. Because input data for the boiling temperature,
molecular weight, density and viscosity were provided, all of these
options are shown in the drop-down list.
HYSYS Oil Manager
If multiple assays are
blended, repeat the steps
outlined in Section 4.9.2 Step 1 - Input Assay Data.
4-87
Figure 4.50
4.9.3 Step 2 - Cut Assay into Hypocomponents
If you have only one Assay, it
is not necessary to enter a
Flow Rate in the Oil Flow
Information table.
You can now cut the Assay into individual hypocomponents. On the
Cut/Blend tab of the Oil Characterization view, select the Add button.
This takes you to the Blend property view with the list of available
assays.
Figure 4.51
4-87
4-88
TBP Assay - Example
From the Available Assays group, select Example and click the Add
button. This adds the Assay to the Oil Flow Information table, and a
Blend (Cut) is automatically calculated. The Blend is calculated because
the default Cut Option, Auto Cut, appears as soon as a Blend is added.
Since the Cut Option was not changed prior to the addition of the
Available Assay to the Blend, HYSYS realizes enough information is
available to cut the oil and the calculations occur automatically.
Instead of using the default Cut Option, the cut points are defined. From
the Cut Option drop-down list, select User Ranges. Enter a Starting Cut
Point Temperature of 100°F and fill out the Cut Point table as shown on
the left. Click the Submit button to calculate the Blend.
The results of the calculation can be viewed on the Tables tab of the
Blend view. The default Table Type is the Component Properties table
with the Main Properties radio button selected in the Table Control
group.
From the drop-down list, you can also view a Component Breakdown,
Molar Compositions, Oil Properties, and Oil Distributions.
Figure 4.52
4-88
HYSYS Oil Manager
Refer to Section 4.6.3 Tables Tab for details on the
information available on the
Tables tab.
4-89
All of the data that is found on the Tables tab can be viewed graphically
from the following three tabs:
•
•
•
Property Plot
Distribution Plot
Composite Plot
On the Distribution Plot tab, select Liquid Volume fraction from the
Basis drop-down list. The following plot is displayed:
Figure 4.53
Refer to the tab subsections in
Chapter 4.6 - Hypocomponent
Generation for information on
the available plots.
The Cut Distribution Plot, as shown above, displays the volume fraction
of the oil that would be recovered in various products. This graph is
particularly useful in providing estimates for distillation products.
4-89
4-90
TBP Assay - Example
4.9.4 Step 3 - Transfer Information to
Flowsheet
The final step of the characterization is to transfer the hypocomponent
information into the flowsheet.
On the Install Oil tab of the Oil Characterization view, enter the Stream
Name Example Oil, to which the oil composition is being transferred.
Figure 4.54
HYSYS assigns the composition of your calculated Oil and Light Ends
into this stream, completing the characterization procedure. Also, the
hypocomponent is placed into a Hypo group named Blend1 and
installed in the fluid package. When you leave the Oil Characterization
environment, you are placed in the Basis environment. It is here that
you can examine individual hypothetical components that make-up
your oil.
4-90
HYSYS Oil Manager
4-91
Enter the Simulation Environment and move to the Workbook to view
the stream you just created. The Compositions page displaying the
stream Example Oil is shown below.
Figure 4.55
If you decide that some of the hypocomponent parameters need to be
recalculated, you can return to the Oil Environment at any time to make
changes. To edit an Assay, highlight it on the Assay tab of the Oil
Characterization property view, and click the Edit button. If you want to
see the effect of using a different correlations on your oil, you can access
this information on the Correlation tab of the Oil Characterization view.
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4-92
TBP Assay - Example
4.9.5 Fluid Package Association
In the example shown in Figure 4.56, there is only one fluid package for
the flowsheet. Specifying the stream name (Example Oil) not only
creates the stream in the flowsheet, but adds the Hypo group (which
contains all of the individual hypocomponents) to the fluid package.
Figure 4.56
In this case, the Oil is Associated with Fluid Package Basis-1
When there are multiple fluid packages in the simulation, you can
specify the one with which the Oil is to be associated (accessed through
the Oil Manager tab of the Simulation Basis Manager view). This serves
two functions: first, it identifies which pure components are available
for a light ends analysis, and second, it identifies the fluid package to
which the Hypo group is being installed.
If you do not want to associate the oil to the fluid package, you can
deactivate the Associate checkbox.
4-92
HYSYS Oil Manager
4-93
4.10 Sulfur Curve - Example
The User Property option in the Oil Characterization environment
allows you to supply a property curve and have HYSYS characterize it
with an Assay. Each hypocomponent is assigned a property value when
the Blend is characterized. You can specify the basis upon which the
property should be calculated (mole, mass or liquid volume, and flows
or fractions), as well as which mixing rule should be used.
In this example, a TBP curve with an associated Sulfur Curve is installed.
There is no Light Ends analysis available, so the Auto Calculate Light
Ends option is used.
4.10.1 Fluid Package
Prior to entering the Oil Characterization environment, create a Fluid
Package with Peng-Robinson as the property method and C1, C2, C3, iC4, and n-C4 as the components. The choice of the Light Ends
components is influenced by the Sulfur Curve data (refer to
Section 4.10.3 - Install the Assay section).
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4-94
Sulfur Curve - Example
4.10.2 Install a User Property
Oil Environment Button
You can also add a User
Property via the User Property
tab in the Simulation Basis
Manager.
Enter the Oil Environment by clicking the Oil Environment button on
the toolbar. To supply a User Curve for an assay, you must first add a
User Property. On the User Property tab of the Oil Characterization
view, select Add to access the User Property view as shown below.
Figure 4.57
The default options are used for the Equation Parameters except for the
Mixing Basis field. Sulfur is quoted on a w/w basis so, select Mass
Fraction from the drop-down list. HYSYS automatically names and
numbers the User Properties. You can provide a descriptive Name for
the property, such as Sulfur.
Note that HYSYS gives you the option of providing a Component User
Property Value for each Light End component. If, for example, this was a
Heating Value Property, you would supply each component value at this
point. These components do not have a “Sulfur value", so they can be
left at 0.
4-94
HYSYS Oil Manager
4-95
4.10.3 Install the Assay
Create an Assay by clicking the Add button on the Assay tab of the Oil
Characterization view. Select TBP as the Assay Data Type, specify a
Liquid Volume% as the Assay Basis, and leave the TBP Distillation
Conditions group at the default settings.
Since no Light Ends analysis is provided, select the Auto Calculate from
the Light Ends drop-down list. The Auto Calculate procedure replaces
the portion of the TBP curve which is covered by the Boiling Point range
of the Light Ends components. In this way, the initial boiling point of the
TBP working curve is slightly higher than the normal boiling point of the
heaviest Light End component.
The TBP curve starts at -25°C. Taking this information into account,
Light End components with boiling points that lie within the first two
percent of the TBP assay were chosen. In this way, the benefits of the
Auto Calculate procedure are gained without losing a significant portion
of our property curve.
There is no Molecular Weight, Density, or Viscosity data, so you can
leave the curve options as Not Used. On the Calculation Defaults tab,
the extrapolation method for the Distillation curve can be left at its
default, Probability. Note that there are no bulk properties. Provide the
boiling temperature data, as tabulated below:
TBP Data
Assay%
Temp (C)
Assay%
Temp (C)
Assay%
Temp (C)
0.02
-25
20.73
180
71.43
500
0.03
-20
24.06
200
73.86
520
0.05
-10
27.55
220
76.22
540
0.31
0
30.93
240
78.46
560
0.52
10
34.32
260
80.57
580
0.55
20
37.83
280
82.55
600
1.25
30
41.21
300
84.41
620
2.53
40
44.51
320
86.16
640
2.93
50
48.01
340
87.79
660
3.78
60
51.33
360
89.32
680
4.69
70
54.58
380
90.67
700
5.67
80
57.73
400
93.48
750
7.94
100
60.65
420
95.74
800
4-95
4-96
Sulfur Curve - Example
TBP Data
Assay%
Temp (C)
Assay%
Temp (C)
Assay%
Temp (C)
10.69
120
63.39
440
98.78
900
13.84
140
66.16
460
17.28
160
68.90
480
The Assay view with the TBP Data is shown below:
Figure 4.58
Sulfur Curve
On the User Curves tab of the Assay property view, select the Available
User Property Sulfur and click the Add button. In the User Curve Data
group, select Independent as the Table Type and ensure that the Bulk
Value cell displays <empty>. Click the Edit button and enter the Sulfur
Curve Data shown below in the Assay Input Table.
Sulfur Curve Data
4-96
Assay%
Sulfur Value
Assay%
Sulfur Value
0.90
0.032
54.08
2.733
7.38
0.026
55.85
2.691
11.48
0.020
57.17
2.669
16.42
0.083
60.00
2.670
HYSYS Oil Manager
4-97
Sulfur Curve Data
Assay%
Sulfur Value
Assay%
Sulfur Value
22.40
0.094
64.47
2.806
26.68
0.212
68.40
3.085
31.78
0.616
72.09
3.481
36.95
1.122
75.66
3.912
42.04
1.693
78.99
4.300
47.14
2.354
82.05
4.656
48.84
2.629
84.85
4.984
50.52
2.786
87.38
5.286
52.22
2.796
90.33
5.646
After this data is entered, click the Calculate button found at the bottom
of the Assay property view.
4.10.4 Create the Blend
A Blend is created using the Auto Cut option. On the Cut\Blend tab of
the Oil Characterization view, select the Add button. On the Data tab of
the Blend view, highlight Assay-1 from the list of Available Assays and
click the Add button. The assay is now added to the Oil Flow
Information table. The Blend is immediately calculated, as the default
Cut Option is Auto Cut.
Figure 4.59
4-97
4-98
Sulfur Curve - Example
4.10.5 Results
Finally, the user property is defined and needs to be installed. On the
Install Oil tab of the Oil Characterization view, specify the Stream Name
as Example Oil to which the oil composition is transferred.
Figure 4.60
HYSYS assigns the composition of your calculated Oil and Light Ends
into this stream, completing the characterization procedure for the User
Property.
4-98
HYSYS Oil Manager
4-99
You can return to the User Property tab of the Oil Characterization view
and click the View button to display the Sulfur User Property view.
Figure 4.61
In the Component User Property Values group, note that the Property
Value is calculated for all the hypocomponents for the blend. You can
scroll through the table to view the Property Value for each
hypocomponent.
4-99
4-100
References
From the Composite Plot tab of the Blend view, you can view a plot of
the Calculated and Inputted values for the User Property. Select User
Property from the Property drop-down list and activate the Sulfur
checkbox to view the following figure.
Figure 4.62
4.11 References
4-100
1
Figure 3A1.1, Chapter 3, API Technical Data Book, Fourth Edition (1980).
2
Procedure 3A1.1, Chapter 3, API Technical Data Book, Fifth Edition (1987).
3
Procedure 3A1.1, Chapter 3, API Technical Data Book, Sixth Edition (1994).
4
Edmister, W.C., and Okamoto, K.K., “Applied Hydrocarbon Thermodynamics,
Part 12: Equilibrium Flash Vaporization Correlations for Petroleum
Fractions”, Petroleum Refiner, August, 1959, p. 117.
5
Procedure 3A3.1, Chapter 3, API Technical Data Book, Fifth Edition (1987).
6
Procedure 3A3.2, Chapter 3, API Technical Data Book, Sixth Edition (1994).
7
Procedure 3A3.1, Chapter 3, API Technical Data Book, Sixth Edition (1994).
Reactions
5-1
5 Reactions
5.1 Introduction......................................................................................2
5.2 Reaction Component Selection......................................................3
5.2.1 Adding Components from Basis Manager................................4
5.2.2 Selections Within the Reaction Manager .................................4
5.2.3 Library Reaction Components..................................................5
5.3 Reactions..........................................................................................6
5.3.1
5.3.2
5.3.3
5.3.4
5.3.5
5.3.6
Manipulating Reactions ............................................................7
Conversion Reaction ................................................................7
Equilibrium Reaction .............................................................. 11
Kinetic Reaction .....................................................................18
Heterogeneous Catalytic Reaction.........................................23
Simple Rate Reaction.............................................................29
5.4 Reaction Sets .................................................................................32
5.4.1
5.4.2
5.4.3
5.4.4
5.4.5
Manipulating Reaction Sets....................................................33
Reaction Set View ..................................................................33
Exporting/Importing a Reaction Set........................................38
Adding a Reaction Set to a Fluid Package.............................39
Reactions in the Build Environment .......................................39
5.5 Generalized Procedure..................................................................40
5.6 Reactions - Example......................................................................42
5.6.1
5.6.2
5.6.3
5.6.4
Add Components to the Reaction Manager ...........................42
Create a Reaction ..................................................................42
Add the Reaction to a Reaction Set .......................................43
Attach the Reaction Set to a Fluid Package...........................44
5-1
5-2
Introduction
5.1 Introduction
Reactions within HYSYS are defined inside the Reaction Manager. The
Reaction Manager, which is located on the Reactions tab of the
Simulation Basis Manager, provides a location from which you can
define an unlimited number of reactions and attach combinations of
these reactions in Reaction Sets. The Reaction Sets are then attached to
Unit Operations in the Flowsheet.
The Reaction Manager is a versatile, time-saving feature that allows you
to do the following:
•
•
•
•
Create a new list of components for the Reactions or simply use
the fluid package components.
Add, Edit, Copy, or Delete Reactions and Reaction Sets.
Attach Reactions to various Reaction Sets or attach Reaction
Sets to multiple Fluid Packages, thus eliminating repetitive
procedures.
Import and Export Reaction Sets.
Figure 5.1
5-2
Reactions
5-3
5.2 Reaction Component Selection
On the Reactions tab of the Simulation Basis Manager, there are three
main groups which are described below:
Group
Description
Rxn
Components
Displays all components available to the Reaction Manager and the
Add Comps button.
Reactions
Displays a list of the defined reactions and four buttons available to
help define reactions.
Reaction Sets
Displays the defined reactions sets, the associated fluid packages
and several buttons that help to define reaction sets and attach them
to fluid packages.
Each of the main groups within the Reaction Manager are examined in
more detail. In this section, the Rxn Components group is described.
The features in the Reactions group and Reaction Sets group are
detailed in subsequent sections.
There are three distinct ways in which components can be made
accessible to Reactions in the Reaction Manager:
Refer to Chapter 1 Components for more
information on adding
components.
•
•
Refer to Section 5.4 Reaction Sets for details on
attaching a fluid package.
•
You can add components on the Component tab of the
Simulation Basis Manager. The components are added to the
component list and are available in the Rxn Components group to
be attached to the Reaction Set. These components are also
included in the fluid package depending on the component list
selected for the package.
You can install components directly in the Reaction Manager
without adding them to a specific component list by clicking the
Add Comps button. The Component List view appears and you
can add reaction components for the reaction. These
components appear automatically in the master component list,
but not in the component list selected for the fluid package. When
a Reaction Set (containing a Reaction which uses the new
components) is attached to a fluid package, the components
which are not present in the fluid package are automatically
transferred.
You can select an Equilibrium Reaction from the Library tab of
the Equilibrium Reactor property view. All components used in
the reaction are automatically installed in the Reaction Manager.
Once the Reaction Set (containing the Library reaction) is
attached to a fluid package, the components are automatically
transferred to the fluid package.
5-3
5-4
Reaction Component Selection
5.2.1 Adding Components from Basis Manager
Hypocomponents created
using the Oil Manager can be
used in Reactions. They are
listed as Associated
Components if they are
installed in a fluid package.
See Chapter 4 - HYSYS Oil
Manager for details on
hypocomponent.
With this method of component selection, components are selected on
the Components tab from the Simulation Basis Manager. Add a
component list by clicking the Add button. From the Component List
View, select the components which are required for the reaction. This is
similar to adding components to a component list for a particular fluid
package or case. All components that are selected are displayed and
available in the Rxn Components group of the Reaction Manager.
The components listed in the Selected Reaction Components group are
available to any Reaction that you create.
5.2.2 Selections Within the Reaction Manager
At least one fluid package
must exist before components
can be transferred from the
Reaction Manager.
Components can be made available prior to the creation of Reactions by
directly selecting them within the Reaction Manager. By selecting the
components within the Reaction Manager, you are not required to
transfer component information from the fluid package. The
components appear in the Master Component list, but not in the
component list. Once a Reaction Set is attached to a fluid package,
HYSYS automatically transfers all of the components contained within
the Reaction(s) to the fluid package.
The following procedure demonstrates the steps required when
beginning with a new case:
1.
Create a new case by clicking the New Case icon on the toolbar.
2.
On the Fluid Pkgs tab of the Simulation Basis Manager, click the Add
button. A new fluid package is created and its property view opens.
Close the Fluid Package property view.
3.
Move to the Reactions tab. Click the Add Comps button in the Rxn
Components group and the Component List view is displayed.
4.
Select either traditional or hypothetical components. The procedure
for selecting components is similar to the selection of components
for the fluid package.
5.
Return to the Reaction Manager to create the Reaction(s) and install
the Reaction(s) within a Reaction Set. See Section 5.3 - Reactions,
and Section 5.4 - Reaction Sets for details.
New Case icon
5-4
Reactions
6.
Attach the Reaction Set to the fluid package created in Step #2. See
Section 5.4.4 - Adding a Reaction Set to a Fluid Package for details.
7.
All components used in the Reaction(s) that are contained within
the Reaction Set are now available in the fluid package.
5-5
5.2.3 Library Reaction Components
When a Library Equilibrium Reaction is selected, all of its constituent
components are automatically added to the Reaction Manager. You can
then use the components in the Rxn Components group of the Reaction
Manager to define other reactions. Library reactions can be installed
prior to the addition of components to the case. You are not required to
add components using the Component List view or Reaction Manager.
To add a Library reaction, do the following:
1.
From the Reaction Manager, click the Add Rxn button in the
Reactions group.
2.
Highlight Equilibrium from the Reactions view and click the Add
Reaction button.
3.
Move to the Library tab of the Equilibrium Reaction property view
and select a reaction from the Library Equilibrium Rxns group.
Figure 5.2
4.
Click the Add Library Rxn button. All library information
concerning the reaction is transferred to the various tabs of the
Equilibrium Reaction property view. The components used by the
reaction are now shown in the Rxn Components group of the
Reaction Manager.
5-5
5-6
Reactions
5.3 Reactions
Refer to Section 5.4 Reaction Sets for information
on Reaction Sets.
In HYSYS, a default reaction set, the Global Rxn Set, is present in every
simulation. All compatible reactions that are added to the case are
automatically included in this set. A Reaction can be attached to a
different set, but it also remains in the Global Rxn Set unless you remove
it. To create a Reaction, click the Add Rxn button from the Reaction
Manager.
The following table describes the five types of Reactions that can be
modeled in HYSYS:
Reaction Type
Requirements
Conversion
Requires the stoichiometry of all the reactions and the conversion of
a base component in the reaction.
Equilibrium
Requires the stoichiometry of all the reactions. The term Ln(K) may
be calculated using one of several different methods, as explained
later. The reaction order for each component is determined from the
stoichiometric coefficients.
Heterogeneous
Catalytic
Requires the kinetics terms of the Kinetic reaction as well as the
Activation Energy, Frequency Factor, and Component Exponent
terms of the Adsorption kinetics.
Kinetic
Requires the stoichiometry of all the reactions, as well as the
Activation Energy and Frequency Factor in the Arrhenius equation
for forward and reverse (optional) reactions. The forward and
reverse orders of reaction for each component can be specified.
Simple Rate
Requires the stoichiometry of all the reactions, as well as the
Activation Energy and Frequency Factor in the Arrhenius equation
for the forward reaction. The Equilibrium Expression constants are
required for the reverse reaction.
Each of the reaction types require that you supply the stoichiometry. To
assist with this task, the Balance Error tracks the molecular weight and
supplied stoichiometry. If the reaction equation is balanced, this error is
equal to zero. If you have provided all of the stoichiometric coefficients
except one, you may select the Balance button to have HYSYS determine
the missing stoichiometric coefficient.
Reactions can be on a phase specific basis. The Reaction is applied only
to the components present in that phase. This allows different rate
equations for the vapour and liquid phase in same reactor operation.
5-6
Reactions
5-7
5.3.1 Manipulating Reactions
When you right-click a
reaction in the Reactions
group, you can select View or
Delete from the Object Inspect
menu.
From the Reaction Manager, you can use the four buttons in the
Reactions group to manipulate reactions. The buttons are described
below:
Button
Command
View Rxn
Accesses the property view of the highlighted reaction.
Add Rxn
Accesses the Reactions view, from which you select a Reaction
type.
Delete Rxn
Removes the highlighted reaction(s) from the Reaction Manager.
Copy Rxn
When selected, the Copy Reactions view appears where you can
select an alternate Reaction Type for the reaction or duplicate the
highlighted reaction.
5.3.2 Conversion Reaction
By default, conversion
reactions are calculated
simultaneously. However you
can specify sequential
reactions using the Ranking
feature. See Section 5.4 Reaction Sets.
The Conversion Reaction requires the Stoichiometric Coefficients for
each component and the specified Conversion of a base reactant. The
compositions of unknown streams can be calculated when the
Conversion is known.
Consider the following Conversion reaction:
b
c
d
A + --- B → --- C + --- D
a
a
a
where:
(5.1)
a, b, c and d = the respective stoichiometric coefficients of the reactants
(A and B) and products (C and D)
A = the base reactant
B = the base reactant not in a limiting quantity
5-7
5-8
Reactions
In general, the reaction components obey the following reaction
stoichiometry:
NA = NA ( 1 – XA )
o
b
N B = N B – --- N X
o
a Ao A
c
N C = N C + --- ( N A X A )
o
o
a
(5.2)
d
N D = N D + --- ( N A X A )
o
o
a
where:
N* = the final moles of component * (*= A, B, C and D)
N*o = the initial moles of component *
XA = the conversion of the base component A
When you have supplied all of
the required information for
the Conversion Reaction, the
status bar (at the bottom right
corner) will change from Not
Ready to Ready.
The moles of a reactant available for conversion in a given reaction
include any amount produced by other reactions, as well as the amount
of that component in the inlet stream(s). An exception to this occurs
when the reactions are specified as sequential.
Stoichiometry Tab
The Stoichiometry tab of a conversion reaction is shown in the figure
below:
Figure 5.3
5-8
Reactions
5-9
For each Conversion reaction, you must supply the following
information:
The Reaction Heat value is
calculated and displayed
below the Balance Error. A
positive value indicates that
the reaction is endothermic.
Input Field
Information Required
Reaction Name
A default name is provided which may be changed. The previous
view shows the name as Rxn-1.
Components
The components to be reacted. A minimum of two components are
required. You must specify a minimum of one reactant and one
product for each reaction you include. Use the drop-down list to
access the available components. The Molecular Weight of each
component is automatically displayed.
Stoichiometric
Coefficient
Necessary for every component in the reaction. The Stoichiometric
Coefficient is negative for a reactant and positive for a product. You
may specify the coefficient for an inert component as 0, which, for
the Conversion reaction, is the same as not including the
component in the table. The Stoichiometric Coefficient does not
have to be an integer; fractional coefficients are acceptable.
Basis Tab
The Basis tab of a conversion reaction is shown in the figure below:
Figure 5.4
5-9
5-10
Reactions
On the Basis tab, you must supply the following information:
You have to add the
components to the reaction
before the Base Component
can be specified.
Sequential Reactions may be
modeled in one reactor by
specifying the sequential order
of solution. See Reaction
Rank, in Section 5.4 Reaction Sets.
Reactions of equal ranking
cannot exceed an overall
conversion of 100%.
Required Input
Description
Base
Component
Only a component that is consumed in the reaction (a reactant) may
be specified as the Base Component (i.e., a reaction product or an
inert component is not a valid choice). You can use the same
component as the Base Component for a number of reactions, and it
is quite acceptable for the Base Component of one reaction to be a
product of another reaction.
Rxn Phase
The phase for which the specified conversions apply. Different
kinetics for different phases can be modeled in the same reactor.
Possible choices for the Reaction Phase are:
• Overall. Reaction occurs in all Phases.
• Vapour Phase. Reaction occurs only in the Vapour Phase.
• Liquid Phase. Reaction occurs only in the Light Liquid Phase.
• Aqueous Phase. Reaction occurs only in the Heavy Liquid
Phase.
• Combined Liquid. Reaction occurs in all Liquid Phases.
Conversion
Function
Parameters
Conversion percentage can be defined as a function of reaction
temperature according to the following equation:
Conv = Co + C1 ⋅ T + C2 ⋅ T
2
This is the percentage of the Base Component consumed in this
reaction. The value of Conv.(%) calculated from the equation is
always limited within the range of 0.0 and 100%.
The actual conversion of any reaction is limited to the lesser of the
specified conversion of the base component or complete
consumption of a limiting reactant.
To define a constant value for conversion percentage, enter a
conversion (%) value for Co only. Negative values for C1 and C2 means
that the conversion drops with increased temperature and vice versa.
5-10
Reactions
5-11
5.3.3 Equilibrium Reaction
The Equilibrium Reaction computes the conversion for any number of
simultaneous or sequential reactions with the reaction equilibrium
parameters and stoichiometric constants you provide.
The Equilibrium constant can be expressed as follows:
Nc
K =
∏
( [ BASE ] e )
vj
(5.3)
j
j=1
This equation is only valid
when BASE (i.e.,
concentration) is at equilibrium
composition.
where:
K = Equilibrium constant
[BASE]ej = Basis for component j at equilibrium
vj = Stoichiometric coefficient for the jth component
Nc = Number of components
The equilibrium constant ln(K) may be considered fixed, or calculated
as a function of temperature based on a number of constants:
Ln ( Keq ) = a + b
(5.4)
where:
B
a = A + --- + C ⋅ ln ( T ) + D ⋅ T
T
When you have supplied all of
the required information for
the Equilibrium Reaction, the
status bar (at the bottom right
corner) changes from Not
Ready to Ready.
2
3
4
b = E⋅T +F⋅T +G⋅T +H⋅T
5
Alternatively, you may supply tabular data (equilibrium constant versus
temperature), and HYSYS automatically calculates the equilibrium
parameters for you. Ln(K) may also be determined from the Gibbs Free
Energy.
5-11
5-12
Reactions
Stoichiometry Tab
The Stoichiometry tab for a equilibrium reaction is shown in the figure
below:
Figure 5.5
For each reaction, you must supply the following information:
5-12
Input Required
Description
Reaction Name
A default name is provided, which may be changed by simply
selecting the field and entering a new name.
Components
A minimum of two components is necessary. You must specify a
minimum of one reactant and one product for each reaction you
include. The Molecular Weight of each component is automatically
displayed.
Stoichiometric
Coefficient
For every component in this reaction. The Stoichiometric Coefficient
is negative for a reactant and positive for a product. You may specify
the coefficient for an inert component as 0. The Stoichiometric
Coefficient need not be an integer; fractional coefficients are
acceptable.
Reactions
5-13
Basis Tab
The Basis tab for an equilibrium reaction contains two groups, the Basis
and the Keq Source, which are shown in the figure below
Figure 5.6
The Basis group requires the following information:
Input Required
Description
Basis
From the drop-down list in the cell, select the Basis for the reaction.
For example, select Partial Pressure or Activity as the basis.
Reaction Phase
The possible choices for the Reaction Phase, accessed from the
drop-down list, are the Vapour and Liquid Phases.
Minimum
Temperature
and Maximum
Temperature
Enter the minimum and maximum temperatures for which the
reaction expressions are valid. If the temperature does not stay
within the specified bounds, a warning message alerts you.
Basis Units
Enter the appropriate units for the Basis, or make a selection from
the drop-down list.
The Keq Source group contains four radio buttons and a checkbox.
•
•
By selecting the appropriate radio button, you can select one of
four options as the Keq Source for the equilibrium reaction.
If the Auto Detect checkbox is checked, HYSYS automatically
changes the Keq Source, depending on the Keq information you
provide. For example, if you enter a fixed equilibrium constant,
the Fixed Keq radio button is automatically selected. If you later
add data to the Table tab, the Keq vs. T Table radio button is
automatically selected.
5-13
5-14
Reactions
Keq Tab
Depending on which option was selected in the Keq Source group (from
the Basis tab), the Keq tab will display the appropriate information.
The following table outlines each of the Keq source options and the
respective view on the Keq tab.
Option
Description
View on Keq Tab
Ln(Keq)
equation
Ln(Keq), assumed to be a function of temperature only, is
determined from the following equation:
Ln ( Keq ) = a + b
where:
B
a = A + --- + C ⋅ ln ( T ) + D ⋅ T
T
2
3
4
b = E⋅T +F⋅T +G⋅T +H⋅T
5
A, B, C, D, E, F, G, H = the constants defined on the Keq tab.
Gibbs
Free
Energy
The equilibrium constant is determined from the default HYSYS
pure component Gibbs Free Energy (G) database and
correlation.
The correlation and database values are valid/accurate for a
temperature (T) range of 25°C to 426.85°C.
If a wider range of G-T correlation is required, the user can clone
the library component and input the components Gibbs Free
Energy correlation to temperatures beyond the default
temperature limit.
5-14
Reactions
Option
Description
Fixed K
In this case, the equilibrium constant Keq is considered to be
fixed, and is thus independent of temperature. You may specify
either Keq or Ln(Keq) on the Keq tab. Check the Log Basis box to
specify the equilibrium constant in the form Ln(Keq).
K vs. T
Table
On the Keq tab, you can provide temperature and equilibrium
constant data. HYSYS estimates the equilibrium constant from
the pairs of data which you provide and interpolates when
necessary. For each pair of data that you provide HYSYS
calculates a constant in the Ln(K) equation. If you provide at least
4 pairs of data, all four constants A, B, C and D are estimated.
5-15
View on Keq Tab
The constants may be changed even after they are estimated
from the pairs of data you provide, simply by entering a new value
in the appropriate cell. If you later want to revert to the estimated
value, simply delete the number in the appropriate cell, and it is
recalculated.
The term R2 gives an indication of the error or accuracy of the
Ln(K) equation. It is equal to the regression sum of squares
divided by the total sum of squares, and is equal to one when the
equation fits the data perfectly.
You can also provide the maximum (T Hi) and minimum (T Lo)
temperatures applicable to the Ln(K) relation. The constants are
always calculated based on the temperature range you provide. If
you provide values in the K Table which are outside the
temperature range, the calculation of the constants is not
affected.
Approach Tab
Under certain process conditions, an equilibrium reaction may not,
actually reach equilibrium. The Equilibrium reaction set uses two types
of approach, Fractional and Temperature, to simulate this type of
situation. You may select either one or both types of approaches for use
in the simulation.
5-15
5-16
Reactions
The Approach tab contains two groups, the Fractional Approach and
Temperature Approach.
Figure 5.7
Temperature Approach is not relevant for a fixed Keq source and thus
the group does not appear when Fixed Keq is selected from the Basis
tab.
Both the Fractional Approach and Temperature Approach methods can
be used to simulate an Equilibrium reaction that is a departure from
equilibrium.
For the Temperature Approach method, the HYSYS reaction solver will
take into account the heat of reaction according to the equations listed.
The direction of non-equilibrium departure depends on whether the
reaction is endothermic or exothermic.
The Fractional Approach method is an alternative to the Temperature
Approach method and is defined according to the following equation:
Feed – Product = Approach% ⋅ ( Feed – Product ) equilibrium
(5.5)
Equation (5.5) could be interpreted as defining the “actual” reaction
extent of the equilibrium as only a percentage of the equilibrium
reaction extent of the reaction. In the solver, the value of Approach % is
limited between 0 and 100%.
5-16
Reactions
5-17
Library Tab
The Library tab allows you to add pre-defined reactions from the HYSYS
Library. The components for the selected Library reaction are
automatically transferred to the Rxn Components group of the Reaction
Manager.
Figure 5.8
When you select a reaction, all data for the reaction, including the
stoichiometry, basis, and Ln(K) parameters, are transferred into the
appropriate location on the Equilibrium Reaction property view. To
access a library reaction, highlight it from the Library Equilibrium Rxns
group and click the Add Library Rxn button.
When K Table contains data input, the library reaction selection will be
blocked. You must click the Erase Table button on the Keq tab and
before you can add a library reaction.
5-17
5-18
Reactions
5.3.4 Kinetic Reaction
To define a Kinetic Reaction, it is necessary to specify the forward
Arrhenius Parameters (the reverse is optional), the stoichiometric
coefficients for each component, and the forward (and reverse) reaction
orders. An iterative calculation occurs, that requires the Solver to make
initial estimates of the outlet compositions. With these estimates, the
rate of reaction is determined. A mole balance is then performed as a
check on the rate of reaction. If convergence is not attained, new
estimates are made and the next iteration is executed.
r A = k ⋅ f ( BASIS ) – k’⋅ f ’( BASIS )
dN A
V
F Ao – F A + ∫ r A dV = ---------dt
When you have supplied all of
the required information for
the Kinetic Reaction, the
status bar (at the bottom right
corner) changes from Not
Ready to Ready.
(5.6)
(5.7)
Equation (5.6) relates the rate of reaction rA with the reaction rate
constants and the basis (e.g. - concentration). Equation (5.7) is a mole
balance on the unit operation; for steady state solutions, the right side is
equal to zero.
Stoichiometry Tab
When the Kinetic Reaction is selected, the following view is displayed:
Figure 5.9
5-18
Reactions
5-19
For each reaction, you must supply the following information:
Input Required
Description
Reaction Name
A default name is provided, which may be changed at any time.
Components
You must specify a minimum of one reactant and one product for
each reaction you include. Access the available components using
the drop-down list. The Molecular Weight of each Component is
automatically displayed.
Stoichiometric
Coefficient
Necessary for every component in the reaction. The Stoichiometric
Coefficient is negative for a reactant and positive for a product. The
Stoichiometric Coefficient need not be an integer; fractional
coefficients are acceptable. You may specify the coefficient for an
inert component as 0, which in most cases is the same as not
including the component in the list. However, you must include
components that have an overall stoichiometric coefficient of zero
and a non-zero order of reaction (i.e., a component that might play
the role of a catalyst). The Kinetic Reaction, which allows you to
specify the Stoichiometric Coefficient and the order of reaction,
makes it possible to correctly model this situation.
Forward and
Reverse Orders
These are reaction orders. HYSYS initially fixes the orders of
reaction according to the corresponding stoichiometric coefficient.
These may be modified by directly entering the new value into the
appropriate cell. For instance, in the following reaction:
CO + Cl 2 → COCl 2
the kinetic rate law is
r CO = k [ CO ] [ Cl 2 ]
3⁄2
When the stoichiometric coefficients are entered for the reaction,
HYSYS sets the forward orders of reaction for CO and Cl2 at 1.
Simply enter 1.5 into the Forward Order cell for Cl2 to correctly
model the reaction order.
Thermodynamic Consistency
Crucial to the specification of the reverse reaction equation is
maintaining thermodynamic consistency so that the equilibrium rate
expression retains the form of Equation (5.3). Failure to do so may
produce erroneous results from HYSYS.
Consider the previously mentioned reaction:
CO + Cl 2 ↔ COCl 2
with the forward kinetics following the relationship:
rate forward = k f [ CO ] [ Cl 2 ]
3⁄2
(5.8)
5-19
5-20
Reactions
Now suppose you want to add the reverse kinetic reaction. Since the
forward reaction is already known, the order of the reverse reaction has
to be derived in order to maintain thermodynamic consistency.
Suppose a generic kinetic relationship is chosen:
α
β
rate backward = k r [ CO ] [ Cl 2 ] [ COCl 2 ]
where:
γ
(5.9)
α, β, and γ = the unknown values of the order of the three components
Equilibrium is defined as the moment when:
rate forward – rate backward = 0
The equilibrium constant K is then equal to:
α
β
γ
kf
[ CO ] [ Cl 2 ] [ COCl 2 ]
K = ---- = --------------------------------------------------------3⁄2
kr
[ CO ] [ Cl ]
(5.10)
2
To maintain the form of the equilibrium equation seen in Equation
(5.3), K is also equal to:
[ COCl 2 ]
K = --------------------------[ CO ] [ Cl 2 ]
(5.11)
Now combining the two relationships for K found in Equation (5.10)
and Equation (5.11):
α
β
γ
[ COCl 2 ]
[ CO ] [ Cl 2 ] [ COCl 2 ]
--------------------------------------------------------- = --------------------------3⁄2
[ CO ] [ Cl 2 ]
[ CO ] [ Cl 2 ]
(5.12)
To maintain thermodynamic consistency: α must be 0, β must be 0.5
and γ must be equal to 1.
5-20
Reactions
5-21
Basis Tab
The Basis tab for a kinetic reaction is shown below:
Figure 5.10
On the Basis tab, the following parameters may be specified:
Input Required
Description
Basis
View the drop-down list in the cell to select the Basis for the
reaction. If, for instance, the rate equation is a function of the partial
pressures, select Partial Pressure as the Basis.
Base
Component
Only a component that is consumed in the reaction (a reactant) may
be specified as the Base Component (i.e., a reaction product or an
inert component is not a valid choice). You can use the same
component as the Base Component for a number of reactions, and it
is quite acceptable for the Base Component of one reaction to be a
product of another reaction.
Reaction Phase
The phase for which the kinetic rate equations apply. Different
kinetic rate equations for different phases can be modeled in the
same reactor. Possible choices for the Reaction Phase, available in
the drop-down list, are: Overall, Vapour Phase, Liquid Phase,
Aqueous Phase, and Combined Liquid.
Minimum
Temperature
and Maximum
Temperature
Enter the minimum and maximum temperatures for which the
forward and reverse reaction Arrhenius equations are valid. If the
temperature does not remain within these bounds, a warning
message alerts you during the simulation.
Basis Units
Enter the appropriate units for the Basis, or make a selection from
the drop-down list.
Rate Units
Enter the appropriate units for the rate of reaction, or make a
selection from the drop-down list.
5-21
5-22
Reactions
Parameters Tab
On the Parameters tab, you may specify the forward and reverse
parameters for the Arrhenius equations. These parameters are used in
the calculation of the forward and reverse reaction constants.
Figure 5.11
The reaction rate constants are a function of temperature according to
the following extended form of the Arrhenius equation:
A, E, β , are the Arrhenius
Parameters for the forward
reaction. A’, E’, and β′ are the
Arrhenius Parameters for the
reverse reaction.
Information for the reverse
reaction is not required.
where:
 E  β
k = A ⋅ exp  – ------------  ⋅ T
 ( RT ) 
(5.13)
 E′  β′
k’ = A’ ⋅ exp  – -------  ⋅ T
 RT 
(5.14)
k = forward reaction rate constant
k’ = reverse reaction rate constant
A = forward reaction Frequency Factor
A’ = reverse reaction Frequency Factor
E = forward reaction Activation Energy
E’ = reverse reaction Activation Energy
β = forward extended reaction rate constant
β′ = reverse extended reaction rate constant
R = Ideal Gas Constant (value and units dependent on the units chosen
for Molar Enthalpy and Temperature)
T = Absolute Temperature
5-22
Reactions
5-23
If the Arrhenius coefficient, A is equal to zero, there is no reaction. If
Arrhenius coefficients E and β are zero, the rate constant is considered
to be fixed at a value of A for all temperatures.
5.3.5 Heterogeneous Catalytic Reaction
HYSYS provides a heterogeneous catalytic reaction kinetics model to
describe the rate of catalytic reactions involving solid catalyst. The rate
equation is expressed in the general form according to Yang and
Hougen (1950):
( kinetic term ) ( potential term )
– r = -----------------------------------------------------------------------( adsorption term )
(5.15)
Since these types of reactions involve surface reaction together with
adsorption (and desorption) of reactants and products, the resulting
rate expression will be strongly mechanism dependent.
Consider the following the simple reaction:
aA + bB → cP
Depending on the reaction mechanism, its reaction rate expression
(ignoring reverse rate of reaction) could be:
Langmuir-Hinshelwood Model
Eley-Rideal Model
Mars-van Krevelen Model
k+ KA KB CA CB
r = ------------------------------------------------------------------------2( 1 + KA CA + KB CB + KP CP )
(5.16)
k+ KB CA CB
r = ------------------------------------------------( 1 + KB CB + KP CP )
(5.17)
kC A
r = --------------------------------------------------------–n
1 + ( a ⁄ b ) ( k ⁄ k∗ )C A C B
(5.18)
5-23
5-24
Reactions
where:
K* = the adsorption rate constant for component *
k+ = the forward reaction rate constant
k = reaction rate constant for oxidation of hydrocarbon
k* = reaction rate constant for surface re-oxidation
HYSYS has provided a general form, as follows, to allow user to build in
the form of rate expression they want to use.
Reactants
kf
∏
i=1
αi
Ci
Products
βj
– kr
∏ Cj
j=1
r = ------------------------------------------------------------------n
M 
M



γ kg 

 1 + ∑  K k ∏ C g 



k = 1
g=1


where:
(5.19)
kf and kr = the Rate Constants of the forward and reverse kinetic rate
expressions
K = the absorption rate constant
M = number of absorbed reactants and products plus absorbed inert
species
The rate constants kf, kr and Kk are all in Arrhenius form. You are
required to prove the Arrhenius parameters (pre-exponential factor A
and activation energy E) for each of these constants.
Note that you may have to group constants, for example in Equation
(5.16), kf = k+ KAKB. You must take care in inputting the correct values of
the Arrhenius equation. Also note that no default values are given for
these constants.
The Heterogeneous Catalytic Reaction option can be used in both CSTR
and PFR reactor unit operations. A typical Reaction Set may include
multiple instances of the Heterogeneous Catalytic Reaction.
5-24
Reactions
5-25
Stoichiometry Tab
When the Heterogeneous Catalytic Reaction is selected, the following
view is displayed:
Figure 5.12
For each catalytic reaction, you must supply the following information:
Input Required
Description
Reaction Name
A default name is provided, which may be changed.
Components
You must specify a minimum of one reactant and one product for
each reaction you include. Open the drop-down list in the cell to
access all of the available components. The Molecular Weight of
each component is automatically displayed.
Stoichiometric
Coefficient
Necessary for every component in this reaction. The Stoichiometric
Coefficient is negative for a reactant and positive for a product. The
Stoichiometric Coefficient need not be an integer; fractional
coefficients are acceptable. You may specify the coefficient for an
inert component as 0, which in this case is the same as not
including the component in the list.
5-25
5-26
Reactions
Basis Tab
The Basis tab for a catalytic reaction is shown below:
Figure 5.13
On the Basis tab, the following parameters may be specified:
5-26
Input Required
Description
Basis
Open the drop-down list in the cell to select the Basis for the
reaction. For example, select Partial Pressure or Molar
Concentration as the basis.
Base
Component
Only a component that is consumed in the reaction (a reactant) may
be specified as the Base Component (i.e., a reaction product or an
inert component is not a valid choice). You can use the same
component as the Base Component for a number of reactions, and it
is acceptable for the Base Component of one reaction to be a
product of another reaction.
Reaction Phase
The phase for which the kinetics apply. Different kinetics for different
phases can be modeled in the same reactor. Possible choices for
the Reaction Phase (available in the drop-down list) are Overall,
Vapour Phase, Liquid Phase, Aqueous Phase, and Combined
Liquid.
Minimum
Temperature
and Maximum
Temperature
Enter the minimum and maximum temperatures for which the
forward and reverse reaction Arrhenius equations are valid. If the
temperature does not remain in these bounds, a warning message
alerts you during the simulation.
Basis Units
Enter the appropriate units for the Basis, or make a selection from
the drop-down list.
Rate Units
Enter the appropriate units for the rate of reaction, or make a
selection from the drop-down list.
Reactions
5-27
Numerator Tab
For more information on
Kinetic reaction specifications
see Section 5.3.4 - Kinetic
Reaction.
The Numerator tab is specified in much the same way as you would
specify a typical HYSYS Kinetic Reaction. The Numerator tab is shown
below:
Figure 5.14
You must supply the forward and reverse parameters of the extended
Arrhenius equation. The forward and reverse reaction rate constants are
calculated from these values. In addition to the rate constants, you must
also specify the reaction order of the various components for both the
forward and reverse reactions. This is done by selecting the
Components field of the Reaction Order cell matrix, and selecting the
appropriate component from the drop-down list and entering values for
the Forward and/or Reverse orders.
When specifying Forward and Reverse relationships it is important to
maintain thermodynamic consistency. For more information on
thermodynamic consistency see Section 5.3.4 - Kinetic Reaction,
Thermodynamic Consistency.
5-27
5-28
Reactions
Denominator Tab
The Denominator tab for a catalytic reaction is shown in the following
figure:
Figure 5.15
The Denominator tab contains the Component Exponents matrix in
which each row represents a denominator term. The A and E columns
are for the pre-exponential factor and the activation energy, respectively
for the adsorption term (K).
M 
M



γ kg 

 1 + ∑  K k ∏ C g 



k = 1
g=1


n
(5.20)
The remaining columns are used to specify the exponents ( γ kg ) of the
absorbed components (Cg). In order to add a term to the denominator
of the kinetic expression, you must activate the row of the matrix
containing the <empty> message and add the relevant equation
parameter values. The Delete Term button is provided to delete the
selected row (or corresponding term) in the matrix. The overall
exponent term n is specified in the Denominator Exponent field.
5-28
Reactions
5-29
5.3.6 Simple Rate Reaction
When you have supplied all of
the required information for
the Simple Rate Reaction, the
status bar (at the bottom right
corner) will change from Not
Ready to Ready.
The Simple Rate Reaction is also similar to the Kinetic Reaction, except
that the reverse reaction rate expression is derived from equilibrium
data.
Stoichiometry Tab
When the Simple Rate Reaction is selected the following view is
displayed.
Figure 5.16
For each reaction, supply the following information:
Field
Description
Reaction Name
A default name is provided, which may be changed.
Components
You must specify a minimum of one reactant and one product for
each reaction you include. Open the drop-down list in the cell to
access all of the available components. The Molecular Weight of
each component is automatically displayed.
Stoichiometric
Coefficient
Necessary for every component in this reaction. The Stoichiometric
Coefficient is negative for a reactant and positive for a product. The
Stoichiometric Coefficient need not be an integer; fractional
coefficients are acceptable. You may specify the coefficient for an
inert component as 0, which in this case is the same as not
including the component in the list.
5-29
5-30
Reactions
Basis Tab
The Basis tab for the simple rate reaction is shown below:
Figure 5.17
On the Basis tab, the following parameters may be specified:
5-30
Parameter
Description
Basis
Open the drop-down list in the cell to select the Basis for the
reaction. For example, select Partial Pressure or Molar
Concentration as the basis.
Base
Component
Only a component that is consumed in the reaction (a reactant) may
be specified as the Base Component (i.e., a reaction product or an
inert component is not a valid choice). You can use the same
component as the Base Component for a number of reactions, and it
is acceptable for the Base Component of one reaction to be a
product of another reaction.
Reaction Phase
The phase for which the kinetics apply. Different kinetics for different
phases can be modeled in the same reactor. Possible choices for
the Reaction Phase, available in the drop-down list, are Overall,
Vapour Phase, Liquid Phase, Aqueous Phase and Combined Liquid.
Minimum
Temperature
and Maximum
Temperature
Enter the minimum and maximum temperatures for which the
forward and reverse reaction Arrhenius equations are valid. If the
temperature does not remain in these bounds, a warning message
alerts you during the simulation.
Basis Units
Enter the appropriate units for the Basis, or make a selection from
the drop-down list.
Rate Units
Enter the appropriate units for the rate of reaction, or make a
selection from the drop-down list.
Reactions
5-31
Parameters Tab
The Parameters tab for the rate reaction is shown below:
Figure 5.18
The forward reaction rate constants are a function of temperature
according to the following extended form of the Arrhenius equation:
β
E
k = A ⋅ exp – ------- ⋅ T
RT
where:
(5.21)
k = forward reaction rate constant
A = forward reaction Frequency Factor
E = forward reaction Activation Energy
β = forward extended reaction rate constant
R = Ideal Gas Constant
T = Absolute Temperature
If Arrhenius coefficient A is equal to zero, there is no reaction. If
Arrhenius coefficients E and β are equal to zero, the rate constant is
considered to be fixed at a value of A for all temperatures.
5-31
5-32
Reaction Sets
The reverse equilibrium constant K’ is considered to be a function of
temperature only:
B′
ln K′ = A′ + ----- + C′ ln ( T ) + D′T
T
where:
(5.22)
A’, B’, C’ and D’ = the reverse equilibrium constants
You must supply at least one of the four reverse equilibrium constants.
5.4 Reaction Sets
All Reaction Sets created within the Reaction Manager become available
for attachment to your reactor operations in the flowsheet. Reaction
Sets may contain more than one reaction. There is limited flexibility for
the mixing of reaction types within a Reaction Set. You can have
Equilibrium and Kinetic reactions within a single Reaction Set, but you
must have a distinct Reaction Set for conversion reactions.
If only one type of reaction is
used, all reactions are active
in the Global Rxn Set, thereby
eliminating the need to
explicitly define a new
Reaction Set.
HYSYS provides the Global Rxn Set, which contains all compatible
reactions that you have defined in the case. If you only add Kinetic and
Equilibrium reactions, or exclusively Conversion reactions to the case,
all reactions are active within the Global Rxn Set. However, if you add an
incompatible mix of reactions (i.e., Conversion and Kinetic), only the
type of reactions that are compatible with the first installed reaction are
active in the Global Rxn Set.
The same reaction can be active in multiple reaction sets. A new set can
be added from the Reaction Manager by selecting the Add Set button.
5-32
Reactions
5-33
5.4.1 Manipulating Reaction Sets
All Reaction Set manipulations are conducted in the Reaction Sets
group of the Reactions tab of the Basis Manager. The following buttons
are available in the Reaction Sets group to manipulate reaction sets:
When you right-click a Reaction
Set in the Reaction Sets group,
you can select View or Delete
from the Object Inspect menu.
Button
Description
View Set
Displays the property view for the highlighted reaction set.
Add Set
Adds a reaction set to the list of reaction sets and opens its property
view.
Delete Set
Removes the highlighted reaction set(s) from the Reaction Manager.
You must confirm your action to delete a reaction set.
Copy Set
Duplicates the highlighted reaction set(s).
Import Set
Opens a reaction set from disk into the current case.
Export Set
Saves a reaction set to disk for use in another case.
Add to FP
Accesses the Add ’Reaction Set Name’ view, from which you attach
the highlighted reaction set(s) to a fluid package. This button is
available only when a Reaction Set is highlighted in the Reaction
Sets group.
5.4.2 Reaction Set View
When you add a new set, or view an existing one, the Reaction Set view
appears as shown below.
Figure 5.19
5-33
5-34
Reaction Sets
The following table describes the features contained within this view.
Feature
Description
Name
A default Reaction Set name is provided, which can be changed.
Set Type
HYSYS determines the Set Type from the reaction types in the
Active List. This field cannot be modified. The Reaction Set types
are Conversion, Kinetic, Equilibrium, and Mixed. A Mixed Set Type
corresponds to a Reaction Set containing both Kinetic and
Equilibrium reactions.
Solver Method
The Solver method is available when dealing with Kinetic reaction
sets. Several Solver Methods are available from the drop-down list
and explained below:
• Default. The Reaction Solver attempts to calculate the
solution using Newton's Method. If this is not successful, it
then uses the Rate Iterated and Rate Integrated Methods. For
most cases, it is best to use the Default Solver Method.
• Newton’s Method. This method usually converges quickly by
taking the derivative of the function using the current
estimates, and uses these results to obtain new estimates.
• Rate Iterated. This method is a partial Newton's method, and
assumes that the off-diagonal elements of the Jacobian matrix
are equal to zero. The Rate Iterated Method works well when
there is very little interaction between reactions.
• Rate Integrated. This method integrates the reaction
equations until all time derivatives are zero. The Rate
Integrated method is stable, but slow.
• Auto Selected. Same as Default.
Active List
Reactions may be added to the Active List by positioning the cursor
in the Active List column and selecting an existing Reaction from the
drop-down list. You may also type the name of an existing reaction
directly in the cell that shows <empty>.
You can open the property view for any reaction in the Active List by
highlighting it and clicking the View Active button. Alternatively, you
may double-click on the reaction to view it.
A reaction in the Active List may be transferred to the Inactive List
simply by selecting the reaction and clicking the Make Inactive
button.
You cannot have two versions
of the same reaction with
different rate constants in the
Active List.
Inactive List
Existing reactions may be added to the Inactive List by positioning
the cursor in the Inactive List column and selecting a Reaction from
the drop-down list.
You can access the property view for any reaction in the Inactive List
by highlighting it and clicking the View Inactive button. You may
also double-click on the reaction to view it.
A reaction in the Inactive List may be transferred to the Active List by
selecting the reaction and clicking the Make Active button. If this
reaction is not independent of other reactions in the Active List, an
error message is displayed, and the reaction remains in the Inactive
List.
Operations
Attached
5-34
All operations to which the Reaction Set is attached are listed in this
column.
Reactions
5-35
Advanced Features
By clicking the Advanced button, you can view the Advanced reaction
options.
Figure 5.20
Within the Volume Continuation Parameters group, the following
options are available:
Object
Description
Volume
Continuation
For most cases, it is not necessary to select this option. In situations
where convergence is not easily attained (e.g., high reaction rates),
check the Volume Continuation checkbox to enable HYSYS to more
easily reach a solution. For Volume Continuation calculations,
HYSYS “ramps” the volume starting from the initial volume fraction
to the final volume fraction in the specified number of steps. For
each successive step, the previous solution is used as the initial
estimate for the next step.
Initial Volume
Fraction
The default value is 1.0000e-06. This is the Volume Fraction at the
start of the calculations.
Number of
Steps
The default value is 10. If the solution does not converge, increase
this value and re-run the simulation.
Current Parm
Value
This field displays the current parameter value.
Current Step
Number
This field displays the current step number.
5-35
5-36
Reaction Sets
Object
Description
Trace Level
Provides a trace output of the calculations in the Trace Window. The
trace level value corresponds to the level of detail that you see in the
Trace Window. You are limited to the values 0, 1, 2, or 3.
Prev Solution
as Estimates
It is necessary to make an initial estimate of the outlet compositions
to obtain the proper solution. Check this checkbox if you want to use
the previous solution as the initial estimate. This does not apply to
the conversion reaction, since the specified conversion determines
the outlet compositions.
Use Iso and
Adia Temp as
Adia Est
If you calculate a heat flow given a specific temperature, and then
use this heat flow as a spec (deleting the temperature specification),
HYSYS uses the previously calculated temperature as an estimate
for the Adiabatic calculation.
The parameters within the Initial Estimate Generation Parameters
group are generally used with Reactions that have a high degree of
interaction. You can also use these parameters to give some assistance
in obtaining the final solution when the reactor operation fails to
converge or when you have a large number of components and
reactions. The parameters are described in the following table:
Parameter
Description
Damping
Factor
Default is 1.0, indicating that there is no damping. You can change
this value. With a lower the damping factor, HYSYS uses smaller
steps (slower and more stable) in converging towards the solution.
Tolerance
This is the tolerance set for the Estimate Generation. By default, this
is set to 0.001. You are able to change this value.
Maximum
Iterations
Maximum number of iterations HYSYS uses. There is no default
value, and so you can set whatever value is desired.
The Reaction Solver Option group allows you to set the number of
iterations and the tolerance level. The option depends on the boundary
condition of the reactor operation which is using the reaction set. For
example, when a reactor operation is used to determine the outlet
temperature, the number of iterations and tolerance level are used in
the reaction solver to search for a solution.
5-36
Option
Description
Max Numb of
Iteration
Controls the maximum number of iterations specified before the
reaction solver stops searching for a solution. By default, the value is
200.
Tolerance
The specified tolerance level is the relative error between the energy
balance equation and the calculated value by the reaction solver in
the iteration. By default, the value is 0.00001.
Reactions
5-37
Reaction Rank
In this case the Rank would
be:
A→B 1
B→C 2
C→D 3
The Ranking button is visible only when the Reaction Set type is
Conversion. This option automatically handles most situations where
reactions are sequential:
A→B
Rxn – 1
B→C
Rxn – 2
C→D
Rxn – 3
allowing the three reactions to be modeled in a single reactor.
However in situations where there are competing reactions:
A+B→C
Rxn – 4
B+D→E
Rxn – 5
you can use the Ranking factor to specify which conversion value should
be applied first. For example, if Rxn-4 was ranked first, the specified
conversion for Rxn-5 would only be applied to the amount of
component B remaining after Rxn-4 had run to its specified conversion.
HYSYS assigns default ranks to multiple conversion reactions by
examining the reactants and products. For example, you may have a
reaction set containing the following:
1. CH4+H2O → CO+3H2
2. CH4+2H2O → CO2+4H2
3. CH4+2O2 → CO2+2H2O
HYSYS notices that a product of Reaction 3, H2O, is used as a reactant
in both Reactions 1 and 2. Since H2O may not be available until Reaction
3 has occurred, it is assigned a rank of 0 and the other reactions are
each given the default Rank of 1. The feed composition is not taken into
account, as Reaction Ranks are assigned prior to entering the Build
Environment.
5-37
5-38
Reaction Sets
To specify the Ranking, you must do so from the Reaction Ranks view,
which contains the following fields:
You can set two or more
reactions to have the same
Rank; for instance, the ranks
for Rxn-1 and Rxn-2 may be
1, and the rank for Rxn-3 may
be 2.
Object
Description
Reaction
This column shows all of the reactions to be ranked.
Rank
Shows the rank for each reaction, which is an integer value. The
minimum value is 0 and the maximum is equal to the number of
Reactions ranked. Thus, when ranking three sequential reactions,
you may rank them 0-1-2 or 1-2-3; both methods give the same
results. You may override the default values through the input of new
values in the appropriate cells.
User Specified
If you specify the Rank of the reaction, this checkbox is checked.
The buttons along the bottom of the Reaction Ranks view have the
following functions:
Button
Description
Cancel
Closes the view without accepting any changes that were made.
Reset
Resets the Reaction Ranks to the internal default.
Accept
Closes the view, accepting the changes that were made.
5.4.3 Exporting/Importing a Reaction Set
After a Reaction Set is customized with reactions, it can be exported to a
file. The same Reaction Set can then be used in another simulation case
by importing the file and attaching it to a fluid package. Highlight a
Reaction Set in the Reaction Sets group of the Reaction Manager and
click the Export Set button.
Figure 5.21
5-38
Reactions
5-39
Select a file path (the default is usually satisfactory) and enter a filename
with the extension *.rst. Click the Save button to export the reaction set
to a file.
The Import Set button allows you to introduce an exported Reaction Set
into a simulation case. Choose the Reaction Set file (with the extension
*.rst) from the list and select the Open button. If the file is not listed in
the File Name field, an alternate File Path may be needed.
5.4.4 Adding a Reaction Set to a Fluid Package
To make a Reaction Set available inside the flowsheet, you must attach it
to the fluid package which is associated with the flowsheet. Highlight a
reaction set in the Reaction Sets group of the Reaction Manager and
click the Add to FP button. The Add ’Reaction Set Name’ view appears,
where you can highlight a fluid package and click the Add Set to Fluid
Package button.
5.4.5 Reactions in the Build Environment
Refer to Section 5.3 Reaction Package of the
User Guide for more details.
When you are inside the Main or Column Environment you can access
the Reaction Package view without having to return to the fluid package.
Under Flowsheet in the Main Menu, select Reaction Package.
Refer to the Operation Guide
for more information on the
individual unit operations.
When a Reaction Set is attached to a unit operation, you can access the
Reaction Set view or the view(s) for the associated Reaction(s) directly
from the property view of the operation. Some of the unit operations
that support reactions include the Reactor operation (conversion,
equilibrium, or kinetic), the PFR, the Separator, and the Column.
5-39
5-40
Generalized Procedure
5.5 Generalized Procedure
The following procedure outlines the basic steps for creating a reaction,
creating a reaction set, adding the reaction to the reaction set and then
making the set available to the flowsheet. Refer to the Reaction Package
view, shown in Figure 5.1, as you follow the procedure:
1.
Select Reaction Package under Flowsheet in the menu bar.
2.
On the Reaction Package view, click the Add Rxn button to create a
new Reaction.
3.
A Reactions view appears, from which you must select the type of
reaction to create. Select a reaction type and click the Add Reaction
button.
4.
The property view for the reaction type you selected is displayed.
Complete the input for the reaction until Ready appears as the
status message. You can close the Reaction property view, if desired.
Figure 5.22
5-40
Reactions
5.
5-41
On the Reaction Package view, click the New Set button to create a
Reaction Set. The Reaction Set view appears.
Figure 5.23
6.
If desired, change the Name of the Reaction Set to better identify it.
7.
To attach the newly created reaction to the Reaction Set, place the
cursor in the <empty> cell of the Active List column. Open the dropdown list in the cell and select a reaction. The reaction becomes
attached to the Reaction Set, as indicated by the activated checkbox
in the OK column.
8.
Click the Close button on the Reaction Set view.
9.
In the Available Reaction Sets group of the Reaction Package view,
highlight the name of the newly created Reaction Set. Notice that
the attached reaction is listed in the Associated Reactions group.
10. Click the Add Set button to make the Reaction Set, and thus the
Reaction, available to unit operations in the flowsheet. The new
Reaction Set is displayed in the Current Reaction Sets group.
5-41
5-42
Reactions - Example
5.6 Reactions - Example
The following procedure demonstrates the minimum steps required for:
•
•
•
•
The addition of components to the Reaction Manager.
The creation of a reaction.
The addition of the reaction to a reaction set.
The attachment of the reaction set to a fluid package.
5.6.1 Add Components to the Reaction Manager
Refer to Section 2.4 - HYSYS
Fluid Package Property
View for details on installing a
fluid package.
For this example, it is assumed that a New Case is created and a fluid
package is installed.
1.
Within the fluid package, the Peng Robinson property package is
selected.
2.
Within the component list, the following set of components are
selected: H2O, CO, CO2, H2, O2, and CH4.
3.
Go to the Reactions tab of the Simulation Basis Manager. The
selected components are present in the Rxn Components group.
5.6.2 Create a Reaction
Refer to Section 5.3 Reactions for information
concerning reaction types and
the addition of reactions.
5-42
1.
To install a reaction, click the Add Rxn button.
2.
From the Reactions view, highlight the Conversion reaction type
and click the Add Reaction button. The Conversion Reaction
property view appears.
3.
On the Stoichiometry tab, select the first row of the Component
column in the Stoichiometry Info table.
4.
Select Methane from the drop-down list. The Mole Weight column
automatically provides the molar weight of methane.
5.
In the Stoich Coeff field, enter -3 (i.e., 3 moles of methane is
consumed).
Reactions
6.
5-43
Now define the rest of the Stoichiometry tab as shown in the figure
below and click the Balance button.
Figure 5.24
7.
Go to the Basis tab and set Methane as the Base Component and
Conversion to 60%. The status bar at the bottom of the property
view now shows a Ready status. Close the property view.
5.6.3 Add the Reaction to a Reaction Set
Refer to Section 5.4 Reaction Sets for details
concerning Reactions Sets.
By default, the Global Rxn Set is present within the Reaction Sets group
when you first display the Reaction Manager. However, for this
procedure, a new Reaction Set is created:
1.
Click the Add Set button. HYSYS provides the name Set-1 and opens
the Reaction Set property view.
2.
To attach the newly created Reaction to the Reaction Set, place the
cursor in the <empty> cell under Active List.
5-43
5-44
Reactions - Example
3.
Open the drop-down list and select the name of the Reaction (Rxn1). The Set Type corresponds to the type of Reaction which you have
added to the Reaction Set. The status is now Ready.
Figure 5.25
4.
Close the view to return to the Reaction Manager.
5.6.4 Attach the Reaction Set to a Fluid Package
5-44
5.
To attach the reaction set to the fluid package, highlight Set-1 in the
Reaction Sets group and click the Add to FP button. When a
Reaction Set is attached to a Fluid Package, it becomes available to
unit operations within the Flowsheet using that particular Fluid
Package.
6.
The Add ’Set-1’ view appears, from which you highlight a fluid
package and click the Add Set to Fluid Package button.
7.
Close the view. Notice that the name of the fluid package appears in
the Assoc. Fluid Pkgs group when the Reaction Set is highlighted in
the Reaction Sets group.
Component Maps
6-1
6 Component Maps
6.1 Introduction......................................................................................2
6.2 Component Maps Tab .....................................................................2
6.2.1 Component Mapping Group .....................................................3
6.2.2 Collections Group.....................................................................3
6.2.3 Maps for Collection Group........................................................3
6.3 Component Map Property View......................................................4
6-1
6-2
Introduction
6.1 Introduction
On the Component Maps tab of the Simulation Basis Manager, you can
map fluid component composition across fluid package boundaries.
Composition values for individual components from one fluid package
can be mapped to a different component in an alternate fluid package.
This is usually done when dealing with hypothetical oil components.
Two previously defined fluid packages are required to perform a
component mapping which is defined as a collection. One fluid package
becomes the target component set and the other becomes the source
component set. Mapping is performed using a matrix of source and
target components. The transfer basis can be performed on a mole,
mass, or liquid volume basis.
6.2 Component Maps Tab
The Component Maps tab of the Simulation Basis Manager is shown
below.
Figure 6.1
6-2
Component Maps
6-3
6.2.1 Component Mapping Group
The Component Mapping group defines the source and target fluid
packages to be mapped. Once two distinct fluid packages are selected,
the Create Collection button creates a collection in the Collections
group.
6.2.2 Collections Group
The Collections group lists all the component mapping collections
currently available. You can change the collection name by selecting the
name you want to edit and typing in the new name.
6.2.3 Maps for Collection Group
The Maps for Collection group allows you to manage your Component
Maps for each collection. The Collection drop-down list lets you select
the collection maps that you want to add, edit, or delete. A default
collection map is added to this list and cannot be deleted. To add a
Component Map based on the currently selected collection, click the
Add button. To view a Component Map, select it from the list and click
the View button. Both the Add and View buttons open the Component
Map Property view. To delete a Component Map, select the map from
the list and click the Delete button.
6-3
6-4
Component Map Property View
6.3 Component Map Property View
Each time a Component Map is created or viewed via the Component
Maps tab of the Simulation Basis Manager, the Component Map
property view opens as shown below:
Figure 6.2
The Component Map property view allows you to map the source
components to the target components in the component matrix. Within
the matrix, you can map all Specifiable (in red) component mapping
values. The following table describes all of the options found in this
view.
6-4
Object
Description
Name
Displays the name of the component map. The name can be
modified within the cell.
View Options
The View Options group provides you with three options in
which to view the component matrix.
• View All. Displays all of the source and target
components in the matrix.
• View Specifiable. Displays only the components that
require values.
• Transpose. Transposes the component matrix.
Component Maps
Object
Description
Component Transfer
Options
The Component Transfer Options group provides two options.
• Unlock all Components. Unlocks all of the component
values, allowing you to specify your own values.
• Transfer Like Hypotheticals. Automatically maps like
hypotheticals.
• Transfer Hypos by NBP. Automatically maps hypos by
NBP. This option is available when you checked the
Transfer Like Hypotheticals checkbox.
Transfer Basis
The Transfer Basis group provides three options that allow you
to define the composition mapping basis:
• Mole
• Mass
• Liq Volume
Multiple Specify
Allows you to specify a value to one or more components at a
time.
Clone from another
Map
Allows you to import values into the mapping matrix from
another map.
Clear All
Removes all of the user defined information from the matrix.
Normalize
Normalizes the mapping matrix.
6-5
6-5
6-6
6-6
Component Map Property View
User Properties
7-1
7 User Properties
7.1 Introduction......................................................................................2
7.2 User Property Tab............................................................................3
7.2.1 Adding a User Property ............................................................4
7.3 User Property View..........................................................................4
7.3.1 Data Tab ...................................................................................5
7.3.2 Notes Tab .................................................................................9
7-1
7-2
Introduction
7.1 Introduction
On the User Property tab of the Simulation Basis Manager, you can
create an unlimited number of user properties for use in the Build
Environment. A User Property is any property that can be defined and
subsequently calculated on the basis of composition.
When User properties are specified, they are used globally throughout
the case. You can supply a User Property value for each component.
User properties can be modified for a specific component, fluid
package, or stream using the property editor.
Refer to Edit Properties
from Section 1.2.3 Manipulating the Selected
Components List for more
information on the property
editor.
Specifying a User Property is similar to supplying a value at the
component level in that it is globally available throughout the case,
unless it is specified otherwise. It is the initial user property value for the
component in the master component list. By selecting the mixing basis
and mixing equation, the total User Property can be calculated.
After a User Property is defined, HYSYS is able to calculate the value of
the property for any flowsheet stream through the User Property utility.
User Properties can also be set as Column specifications.
7-2
User Properties
7-3
7.2 User Property Tab
The User Property tab of the Simulation Basis Manager is shown below:
Figure 7.1
The available User Properties are listed in the User Properties group.
The following User Property manipulation buttons are available:
A User Property can also be
added or viewed through the
Oil Characterization - User
Property tab.
Refer to Chapter 7.3 - User
Property View for
descriptions of the User
Property Parameters.
Button
Description
View
Edit the currently highlighted User Property.
Add
Create a new User Property.
Delete
Erase the currently highlighted User Property. HYSYS will not
prompt for confirmation when deleting a User Property, so be careful
when you are using this command.
In the User Property Parameters group, all information pertaining to the
highlighted property in the User Property group is displayed. You can
edit the User Property parameters directly on the Simulation Basis view
or click on the View button for the User Property view.
7-3
7-4
User Property View
7.2.1 Adding a User Property
To add a user property, follow the steps below:
1.
On the User Property tab of the Simulation Basis Manager, click the
Add button. The User Property view is displayed.
2.
Provide a descriptive Name for the user property on Simulation
Basis view.
3.
In the User Property Parameters group, select a Mixing Basis using
the drop-down list within the cell.
4.
Select a Mixing Rule.
5.
You can modify the two Mixing Parameters (F1 and F2) to more
accurately reflect your property formula.
6.
Select a Unit Type from the filtered drop-down list.
7.
Input initial property values for each component.
7.3 User Property View
Each time a User Property is created through the User Property tab of
the Simulation Basis Manager, the User Property view is displayed. The
User Property view has two tabs, the Data tab and the Notes tab. All
information regarding the calculation of the User Property is specified
on the Data tab.
7-4
User Properties
7-5
7.3.1 Data Tab
On the Data tab, the Basic user prop definition, and the Initial user
property value groups are displayed.
Figure 7.2
7-5
7-6
User Property View
Basic User Property Definition Group
The following options are available for Process type properties:
Parameter
Description
Mixing Basis
You have the following options: Mole Fraction, Mass Fraction,
Liquid Volume Fraction, Mole Flow, Mass Flow, and Liquid Volume
Flow.
All calculations are performed using compositions in HYSYS
internal units. If you have specified a flow basis (molar, mass or
liquid volume flow), HYSYS uses the composition as calculated in
internal units for that basis.
For example, a User Property with a Mixing Basis specified as
molar flow is always calculated using compositions in kg mole/s,
regardless of what the current default units are.
Mixing Rule
Select from one of three mixing rules:
( P mix )
f1
N
= f 2 ∑ ( x ( i )P ( i ) )
f1
(7.1)
i=1
( P mix )
f1
N
= f 2 ∑ ( x ( i ) ln ( P ( i ) ) )
f1
(7.2)
i=1
N
Index =
∑ x ( i ) ( f 1 ⋅P ( i ) + 10
f 2⋅ P(i)
)
(7.3)
i=1
where:
Pmix = total user property value
P(i) = input property value for component
x(i) = component fraction or flow, depending on the chosen
Mixing Basis
Index = blended (total) index value
f1 and f2 are specified constants
Mixing
Parameters
The mixing parameters f1 and f2 are 1.00 by default. You may
supply any value for these parameters.
Unit Type
This option allows you to select the variable type for the user
property.
For example, if you have a temperature user property, select
temperature in the unit type using the drop-down list.
7-6
User Properties
7-7
Mixing Rules
As listed previously, there are three mixing rules available when you are
defining a user property. Equation (7.1) and Equation (7.2) are
relatively straightforward. The index mixing rule, Equation (7.3), is
slightly more complex.
With the index mixing rule, HYSYS allows you to combine properties
that are not inherently linear. A property is made linear through the use
of the index equation.
The form of your index
equation must resemble the
HYSYS index equation such
that you can supply the f1 and
f2 parameters. Some common
properties which can make
use of the Index equation
include R.O.N., Pour Point and
Viscosity.
Equation (7.3) can be simplified into the following equations:
Index i = f 1 ⋅ P ( i ) + 10
f 2⋅ P(i)
(7.4)
N
Index =
∑ x ( i ) ⋅ Indexi
(7.5)
i=1
Index = f1 ⋅ P + 10
f 2⋅ P
(7.6)
You supply the individual component properties (Pi) and the index
equation parameters (i.e., f1 and f2). Using Equation (7.4), HYSYS
calculates an individual index value for each supplied property value.
The sum of the index values, which is the blended index value, is then
calculated using the Mixing Basis you have selected (Equation (7.5)).
The blended index value is used in an iterative calculation to produce
the blended property value (P in Equation (7.6)). The blended property
value is the value which will be displayed in the user property utility.
7-7
7-8
User Property View
Initial User Property Values for All Components Group
User Property values can be
assigned to hypocomponent
during the characterization of
an oil. Refer to Section 7.2.1 Adding a User Property for
more information.
The purpose of this view is to instruct HYSYS how the User Property
should be initialized throughout the case. Whenever the value of a User
Property is requested by the User Property utility or by the column
specification, HYSYS uses the composition in the specified basis, and
calculate the User Property value using your mixing rule and
parameters.
Refer to Chapter 14 - Utilities
of the Operations Guide for
more information on the User
Property utility.
The values for pure components are always used for the property and
are not overwritten by the synthesis. The values for hypocomponents
are only used if the synthesis of the property can not be achieved. For
example, if there are insufficient number of data points. To specify a
Property Value, click on the Edit component user property values
button.
Refer to Chapter 8 - Column
of the Operations Guide for
information on the User
Property specification.
Edit Component User Property Values
This view allows you to edit initial user property values for components
in the master component list.
Figure 7.3
Once property values are entered or edited, click the Submit button
which allows all values to be modified at one time. The changes are
reflected on the User Property view for each component.
7-8
User Properties
7-9
7.3.2 Notes Tab
HYSYS provides a tab where you can enter a description of the User
Properties for your own future reference.
7-9
7-10
7-10
User Property View
Property Methods & Calculations
A-1
A Property Methods &
Calculations
A.1 Introduction .....................................................................................3
A.2 Selecting Property Methods...........................................................4
A.3 Property Methods............................................................................9
A.3.1
A.3.2
A.3.3
A.3.4
A.3.5
A.3.6
Equations of State....................................................................9
Activity Models .......................................................................16
Activity Model Vapour Phase Options....................................35
Semi-Empirical Methods ........................................................37
Vapour Pressure Property Packages.....................................38
Miscellaneous - Special Application Methods........................41
A.4 Enthalpy & Entropy Departure Calculations ..............................45
A.4.1 Equations of State..................................................................45
A.4.2 Activity Models .......................................................................47
A.4.3 Lee-Kesler Option ..................................................................49
A.5 Physical & Transport Properties..................................................51
A.5.1
A.5.2
A.5.3
A.5.4
A.5.5
A.5.6
A.5.7
Liquid Density ........................................................................52
Vapour Density.......................................................................53
Viscosity.................................................................................53
Liquid Phase Mixing Rules for Viscosity ................................55
Thermal Conductivity .............................................................56
Surface Tension .....................................................................58
Heat Capacity ........................................................................59
A.6 Volumetric Flow Rate Calculations .............................................59
A.6.1
A.6.2
A.6.3
A.6.4
Available Flow Rates .............................................................60
Liquid & Vapour Density Basis...............................................60
Formulation of Flow Rate Calculations ..................................62
Volumetric Flow Rates as Specifications ...............................64
A-1
A-2
Property
A.7 Flash Calculations ........................................................................ 65
A.7.1
A.7.2
A.7.3
A.7.4
A.7.5
A.7.6
A.7.7
A.7.8
A.7.9
T-P Flash Calculation ............................................................ 66
Vapour Fraction Flash............................................................ 66
Enthalpy Flash ....................................................................... 68
Entropy Flash ........................................................................ 68
Electrolyte Flash .................................................................... 68
Handling of Water .................................................................. 69
Supercritical Handling............................................................ 71
Solids ..................................................................................... 72
Stream Information ................................................................ 73
A.8 References .................................................................................... 75
A-2
Property Methods & Calculations
A-3
A.1 Introduction
This appendix is organized such that the detailed calculations that occur
within the Simulation Basis Manager and within the Flowsheet are
explained in a logical manner.
•
•
•
•
•
•
•
In the first section, an overview of property method selection is
presented. Various process systems and their recommended
property methods are listed.
Detailed information is provided concerning each individual
property method available in HYSYS. This section is further
subdivided into equations of state, activity models, Chao-Seader
based semi-empirical methods, vapour pressure models, and
miscellaneous methods.
Following the detailed property method discussion is the section
concerning enthalpy and entropy departure calculations. The
enthalpy and entropy options available within HYSYS are largely
dependent upon your choice of a property method.
The physical and transport properties are covered in detail. The
methods used by HYSYS in calculating liquid density, vapour
density, viscosity, thermal conductivity, and surface tension are
listed.
HYSYS handles volume flow calculations in a unique way. To
highlight the methods involved in calculating volumes, a separate
section is provided.
The next section ties all of the previous information together.
Within HYSYS, the Flash calculation uses the equations of the
selected property method, as well as the physical and transport
property functions to determine all property values for Flowsheet
streams. After a flash calculation is performed on an object, all of
its thermodynamic, physical and transport properties are defined.
The flash calculation in HYSYS does not require initial guesses or
the specification of flash type to assist in its convergence.
A list of References is included at the end of the Appendix.
A-3
A-4
Selecting Property Methods
A.2 Selecting Property Methods
The property packages available in HYSYS allow you to predict
properties of mixtures ranging from well defined light hydrocarbon
systems to complex oil mixtures and highly non-ideal (non-electrolyte)
chemical systems. HYSYS provides enhanced equations of state (PR and
PRSV) for rigorous treatment of hydrocarbon systems; semi-empirical
and vapour pressure models for the heavier hydrocarbon systems;
steam correlations for accurate steam property predictions; and activity
coefficient models for chemical systems. All of these equations have
their own inherent limitations and you are encouraged to become more
familiar with the application of each equation.
The following table lists some typical systems and recommended
correlations. However, when in doubt of the accuracy or application of
one of the property packages, contact Hyprotech to receive additional
validation material or our best estimate of its accuracy.
Type of System
A-4
Recommended Property Method
TEG Dehydration
PR
Sour Water
PR, Sour PR
Cryogenic Gas Processing
PR, PRSV
Air Separation
PR, PRSV
Atm Crude Towers
PR, PR Options, GS
Vacuum Towers
PR, PR Options, GS (<10 mm Hg),
Braun K10, Esso K
Ethylene Towers
Lee Kesler Plocker
High H2 Systems
PR, ZJ or GS (see T/P limits)
Reservoir Systems
PR, PR Options
Steam Systems
Steam Package, CS or GS
Hydrate Inhibition
PR
Chemical systems
Activity Models, PRSV
HF Alkylation
PRSV, NRTL (Contact Hyprotech)
TEG Dehydration with Aromatics
PR (Contact Hyprotech)
Hydrocarbon systems where H2O
solubility in HC is important
Kabadi Danner
Systems with select gases and light
hydrocarbons
MBWR
Property Methods & Calculations
A-5
For oil, gas and petrochemical applications, the Peng-Robinson EOS
(PR) is generally the recommended property package. Hyprotech’s
enhancements to this equation of state enable it to be accurate for a
variety of systems over a wide range of conditions. It rigorously solves
any single, two-phase or three-phase system with a high degree of
efficiency and reliability, and is applicable over a wide range of
conditions, as shown in the following table.
The range of applicability in
many cases is more indicative
of the availability of good data
rather than on the actual
limitations.
Method
Temp (°F)
Temp (°C)
Pressure (psia)
Pressure (kPa)
PR
> -456
> -271
< 15,000
< 100,000
SRK
> -225
> -143
< 5,000
< 35,000
The PR equation of state is enhanced to yield accurate phase
equilibrium calculations for systems ranging from low temperature
cryogenic systems to high temperature, high pressure reservoir systems.
The same equation of state satisfactorily predicts component
distributions for heavy oil systems, aqueous glycol and CH3OH systems,
and acid gas/sour water systems, although specific sour water models
(Sour PR and Sour SRK) are available for more specialized treatment.
Our high recommendation for the PR equation of state is largely due to
the preferential attention that is given to it by Hyprotech. Although the
Soave-Redlich-Kwong (SRK) equation also provides comparable results
to the PR in many cases, it is known that its range of application is
significantly limited and it is not as reliable for non-ideal systems. For
example, it should not be used for systems with CH3OH or glycols.
As an alternate, the PRSV equation of state should also be considered. It
can handle the same systems as the PR equation with equivalent, or
better accuracy, plus it is more suitable for handling moderately nonideal systems.
The advantage of the PRSV equation is that not only does it have the
potential to more accurately predict the phase behaviour of
hydrocarbon systems, particularly for systems composed of dissimilar
components, but it can also be extended to handle non-ideal systems
with accuracies that rival traditional activity coefficient models. The
only compromise is increased computational time and the additional
interaction parameter that is required for the equation.
A-5
A-6
Selecting Property Methods
The PR and PRSV equations of state perform rigorous three-phase flash
calculations for aqueous systems containing H2O, CH3OH or glycols, as
well as systems containing other hydrocarbons or non-hydrocarbons in
the second liquid phase. For SRK, H2O is the only component that
initiates an aqueous phase. The Chao-Seader (CS) and Grayson-Streed
(GS) packages can also be used for three-phase flashes, but are restricted
to the use of pure H2O for the second liquid phase.
The PR can also be used for crude systems, which have traditionally
been modeled with dual model thermodynamic packages (an activity
model representing the liquid phase behaviour, and an equation of state
or the ideal gas law for the vapour phase properties). These earlier
models are suspect for systems with large amounts of light ends or when
approaching critical regions. Also, the dual model system leads to
internal inconsistencies. The proprietary enhancements to the PR and
SRK methods allow these EOSs to correctly represent vacuum
conditions and heavy components (a problem with traditional EOS
methods), as well as handle the light ends and high-pressure systems.
Activity Models, which handle highly non-ideal systems, are much more
empirical in nature when compared to the property predictions in the
hydrocarbon industry. Polar or non-ideal chemical systems are
traditionally handled using dual model approaches. In this type of
approach, an equation of state is used for predicting the vapour fugacity
coefficients and an activity coefficient model is used for the liquid
phase. Since the experimental data for activity model parameters are
fitted for a specific range, these property methods cannot be used as
reliably for generalized application.
The CS and GS methods, though limited in scope, may be preferred in
some instances. For example, they are recommended for problems
containing mainly liquid or vapour H2O because they include special
correlations that accurately represent the steam tables. The Chao Seader
method can be used for light hydrocarbon mixtures, if desired. The
Grayson-Streed correlation is recommended for use with systems
having a high concentration of H2 because of the special treatment
given H2 in the development of the model. This correlation may also be
slightly more accurate in the simulation of vacuum towers.
A-6
Property Methods & Calculations
A-7
The Vapour Pressure K models, Antoine, BraunK10 and EssoK models,
are designed to handle heavier hydrocarbon systems at lower pressures.
These equations are traditionally applied for heavier hydrocarbon
fractionation systems and consequently provide a good means of
comparison against rigorous models. They should not be considered for
VLE predictions for systems operating at high pressures or systems with
significant quantities of light hydrocarbons.
The Property Package methods in HYSYS are divided into basic
categories, as shown in the following table. With each of the property
methods listed are the available methods of VLE and Enthalpy/Entropy
calculation.
Please refer to Section A.4 - Enthalpy & Entropy Departure
Calculations, for a description of Enthalpy and Entropy calculations.
Property Method
VLE Calculation
Enthalpy/Entropy
Calculation
Equations of State
PR
PR
PR
PR LK ENTH
PR
Lee-Kesler
SRK
SRK
SRK
SRK LK ENTH
SRK
Lee-Kesler
Kabadi Danner
Kabadi Danner
SRK
Lee Kesler Plocker
Lee Kesler Plocker
Lee Kesler
PRSV
PRSV
PRSV
PRSV LK
PRSV
Lee-Kesler
Sour PR
PR & API-Sour
PR
SOUR SRK
SRK & API-Sour
SRK
Zudkevitch-Joffee
Zudkevitch-Joffee
Lee-Kesler
Chien Null
Chien Null
Cavett
Extended and General
NRTL
NRTL
Cavett
Margules
Margules
Cavett
NRTL
NRTL
Cavett
UNIQUAC
UNIQUAC
Cavett
van Laar
van Laar
Cavett
Wilson
Wilson
Cavett
Ideal
Ideal Gas
Activity Models
Liquid
Vapour
Ideal Gas
A-7
A-8
Selecting Property Methods
Property Method
VLE Calculation
Enthalpy/Entropy
Calculation
RK
RK
RK
Virial
Virial
Virial
Peng Robinson
Peng Robinson
Peng Robinson
SRK
SRK
SRK
Chao-Seader
CS-RK
Lee-Kesler
Grayson-Streed
GS-RK
Lee-Kesler
Mod Antoine-Ideal Gas
Lee-Kesler
Semi-Empirical Models
Vapour Pressure Models
Mod Antoine
Braun K10
Braun K10-Ideal Gas
Lee-Kesler
Esso K
Esso-Ideal Gas
Lee-Kesler
Miscellaneous - Special Application Methods
Amines
Mod Kent Eisenberg
(L), PR (V)
Curve Fit
ASME Steam
ASME Steam Tables
ASME Steam Tables
NBS Steam
NBS/NRC Steam
Tables
NBS/NRC Steam
Tables
MBWR
Modified BWR
Modified BWR
Steam Packages
A-8
Property Methods & Calculations
A-9
A.3 Property Methods
Details of each individual property method available in HYSYS are
provided in this section, including equations of state, activity models,
Chao-Seader based empirical methods, vapour pressure models, and
miscellaneous methods.
A.3.1 Equations of State
It is important to note that the
properties predicted by
HYSYS’ PR and SRK
equations of state do not
necessarily agree with those
predicted by the PR and SRK
of other commercial
simulators.
HYSYS currently offers the enhanced Peng-Robinson1 (PR), and SoaveRedlich-Kwong2 (SRK) equations of state. In addition, HYSYS offers
several methods which are modifications of these property packages,
including PRSV, Zudkevitch Joffee (ZJ) and Kabadi Danner (KD). Lee
Kesler Plocker3 (LKP) is an adaptation of the Lee Kesler equation for
mixtures, which itself was modified from the BWR equation. Of these,
the Peng-Robinson equation of state supports the widest range of
operating conditions and the greatest variety of systems. The PengRobinson and Soave-Redlich-Kwong equations of state (EOS) generate
all required equilibrium and thermodynamic properties directly.
Although the forms of these EOS methods are common with other
commercial simulators, they have been significantly enhanced by
Hyprotech to extend their range of applicability.
The Peng-Robinson property package options are PR, Sour PR, and
PRSV. Soave-Redlich-Kwong equation of state options are the SRK, Sour
SRK, KD and ZJ.
PR & SRK
The PR or SRK EOS should
not be used for non-ideal
chemicals such as alcohols,
acids or other components.
They are more accurately
handled by the Activity Models
(highly non-ideal) or the PRSV
EOS (moderately non-ideal).
The PR and SRK packages contain enhanced binary interaction
parameters for all library hydrocarbon-hydrocarbon pairs (a
combination of fitted and generated interaction parameters), as well as
for most hydrocarbon-nonhydrocarbon binaries.
For non-library or hydrocarbon hypocomponent, HC-HC interaction
parameters are generated automatically by HYSYS for improved VLE
property predictions.
A-9
A-10
Property Methods
The PR equation of state applies a functionality to some specific
component-component interaction parameters. Key components
receiving special treatment include He, H2, N2, CO2, H2S, H2O, CH3OH,
EG and TEG. For further information on application of equations of
state for specific components, contact Hyprotech.
The following page provides a comparison of the formulations used in
HYSYS for the PR and SRK equations of state.
Soave Redlich Kwong
Peng Robinson
a
RT
P = ------------ – --------------------V – b V(V + b)
3
2
2
Z – Z + ( A – B – B )Z – AB = 0
a
RT
P = ------------ – ------------------------------------------------V – b V(V + b) + b(V – b)
3
2
2
2
3
Z – ( 1 – B ) Z + ( A – 2B – 3B )Z – ( AB – B – B ) = 0
where
b=
N
N
∑ xi bi
∑ xi bi
i=1
bi=
a=
i=1
RT ci
0.08664 ----------P ci
N
RT ci
0.077796 ----------P ci
N
N
∑∑
xi xj ( ai aj )
0.5
( 1 – k ij )
aci=
αi0.5 =
mi=
∑ ∑ xi xj ( ai aj )
0.5
( 1 – k ij )
i = 1 j =1
i = 1 j =1
ai=
N
a ci α i
a ci α i
2
2
( RT ci )
0.42747 -----------------P ci
( RT ci )
0.457235 -----------------P ci
0.5
1 + m i ( 1 – T ri )
0.5
1 + m i ( 1 – T ri )
2
0.48 + 1.574ω i – 0.176ω i
2
0.37464 + 1.54226ω i – 0.26992ω i
When an acentric factor > 0.49 is present HYSYS uses
following corrected form:
0.379642 + ( 1.48503 – ( 0.164423 – 1.016666ω i )ω i )ω i
A-10
A=
aP
-------------2( RT )
aP
-------------2( RT )
B=
bP
------RT
bP
------RT
Property Methods & Calculations
A-11
Kabadi Danner
This KD4 model is a modification of the original SRK equation of State,
enhanced to improve the vapour-liquid-liquid equilibria calculations
for H2O-hydrocarbon systems, particularly in the dilute regions.
The model is an improvement over previous attempts which were
limited in the region of validity. The modification is based on an
asymmetric mixing rule, whereby the interaction in the water phase
(with its strong H2 bonding) is calculated based on both the interaction
between the hydrocarbons and the H2O, and on the perturbation by
hydrocarbon on the H2O-H2O interaction (due to its structure).
Lee Kesler Plöcker Equation
The Lee Kesler Plöcker
equation does not use the
COSTALD correlation in
computing liquid density. This
may result in differences when
comparing results between
equation of states.
The Lee Kesler Plöcker equation is an accurate general method for nonpolar substances and mixtures. Plöcker et al.3 applied the Lee Kesler
equation to mixtures, which itself was modified from the BWR equation.
z = z
(o)
ω (r) (o)
+ --------(z – z )
(r)
ω
(A.1)
The compressibility factors are determined as follows:
pr vr
pv
z = ------- = ---------- = z ( T r, v r, A k )
RT
Tr
(A.2)
C4
–γ
γ
B C D
- β + ----- exp ----2z = 1 + ---- + ----2- + ----5- + ---------3 2
2
vr vr vr Tr vr
vr
vr
(A.3)
A-11
A-12
Property Methods
where:
pc v
v r = --------RT c
b2 b3 b4
B = b 1 – ----- – -----2 – -----3
Tr Tr Tr
c2 c3
C = c 1 – ----- + -----2
Tr Tr
ω
(o)
d
D = d 1 – ----2Tr
ω
= 0
(r)
= 0.3978
Mixing rules for pseudocritical properties are as follows:
 1 
- ∑ ∑ x i x j v c
T cm =  -------ij
 V ηcm
i
Tc = ( Tc Tc )
ij
vc =
m
i
1⁄2
∑ ∑ xi xj vc
i
Tc = Tc
ii
j
(A.4)
j
i
Tc = Tc
jj
j
1 1⁄3
1⁄3 3
v c = --- ( v c + v c )
ij
j
8 i
ij
j
RT c
v c = z c ----------i
i
i p
c
z c = 0.2905 – 0.085ω i
RT c
p c = z c -----------mm
m v
c
z c = 0.2905 – 0.085ω m
i
i
m
m
ωm =
∑ xi ωi
i
Peng-Robinson Stryjek-Vera
The Peng-Robinson Stryjek-Vera (PRSV) equation of state is a two-fold
modification of the PR equation of state that extends the application of
the original PR method for moderately non-ideal systems. It is shown to
match vapour pressures curves of pure components and mixtures more
accurately than the PR method, especially at low vapour pressures.
A-12
Property Methods & Calculations
A-13
It is successfully extended to handle non-ideal systems giving results as
good as those obtained using excess Gibbs energy functions like the
Wilson, NRTL or UNIQUAC equations.
One of the proposed modifications to the PR equation of state by Stryjek
and Vera was an expanded alpha, "α", term that became a function of
acentricity and an empirical parameter, κi, used for fitting pure
component vapour pressures.
0.5 2
αi = [ 1 + κi ( 1 – Tr ) ]
0.5
0.5
κ i = κ 0i + κ 1i ( 1 + T r ) ( 0.7 – T r )
i
(A.5)
i
2
3
κ 0i = 0.378893 + 1.4897153ω i – 0.17131848ω i + 0.0196554ω i
where:
κ 1i = characteristic pure component parameter
ω i = acentric factor
The adjustable κ1i term allows for a much closer fit of the pure
component vapour pressure curves. This term is regressed against the
pure component vapour pressure for all components in HYSYS’ library.
For hypocomponent that are generated to represent oil fractions,
HYSYS automatically regresses the κ1i term for each hypocomponent
against the Lee-Kesler vapour pressure curves. For individual useradded hypothetical components, κ1i terms can either be entered or they
are automatically regressed against the Lee-Kesler, Gomez-Thodos or
Reidel correlations.
If kij =kji, the mixing rules
reduce to the standard PR
equation of state.
The second modification consists of a new set of mixing rules for
mixtures. Conventional mixing rules are used for the volume and energy
parameters in mixtures, but the mixing rule for the cross term, aij, is
modified to adopt a composition dependent form. Although two
different mixing rules were proposed in the original paper, HYSYS has
incorporated only the Margules expression for the cross term.
a ij = ( a ii a jj )
where:
0.5
( 1.0 – x i k ij – x j k ji )
(A.6)
k ij ≠ k ji
A-13
A-14
Different values can be
entered for each of the binary
interaction parameters.
Property Methods
Although only a limited number of binary pairs are regressed for this
equation, our limited experience suggests that the PRSV can be used to
model moderately non-ideal systems such as H2O-alcohol systems,
some hydrocarbon-alcohol systems. You can also model hydrocarbon
systems with improved accuracy. Also, due to PRSV’s better vapour
pressure predictions, improved heat of vaporization predictions should
be expected.
Sour Water Options
The Sour option is available for both the PR and SRK equations of state.
The Sour PR option combines the PR equation of state and Wilson’s APISour Model for handling sour water systems, while Sour SRK utilizes the
SRK equation of state with the Wilson model.
The Sour options use the appropriate equation of state for calculating
the fugacities of the vapour and liquid hydrocarbon phases as well as
the enthalpy for all three phases. The K-values for the aqueous phase are
calculated using Wilson’s API-Sour method. This option uses Wilson’s
model to account for the ionization of the H2S, CO2 and NH3 in the
aqueous water phase. The aqueous model employs a modification of
Van Krevelen’s original model with many of the key limitations
removed. More details of the model are available in the original API
publication 955 titled "A New Correlation of NH3, CO2, and H2S
Volatility Data from Aqueous Sour Water Systems".
It is important to note that
because the method performs
an ion balance for each Kvalue calculation, the flash
calculation is much slower than
the standard EOS.
The original model is applicable for temperatures between 20°C (68°F)
and 140°C (285°F), and pressures up to 50 psi. Use of either the PR or
SRK equation of state to correct vapour phase non idealities extends this
range, but due to lack of experimental data, exact ranges cannot be
specified. The acceptable pressure ranges for HYSYS' model vary
depending upon the concentration of the acid gases and H2O. The
method performs well when the H2O partial pressure is below 100 psi.
This option may be applied to sour water strippers, hydrotreater loops,
crude columns or any process containing hydrocarbons, acid gases and
H2O. If the aqueous phase is not present, the method produces identical
results to the EOS, (PR or SRK depending on which option you have
chosen).
A-14
Property Methods & Calculations
A-15
Zudkevitch Joffee
The Zudkevitch Joffee model is a modification of the Redlich Kwong
equation of state. This model is enhanced for better prediction of
vapour liquid equilibria for hydrocarbon systems, and systems
containing H2. The major advantage of this model over the previous
version of the RK equation is the improved capability of predicting pure
component equilibria, and the simplification of the method for
determining the required coefficients for the equation.
Enthalpy calculations for this model are performed using the Lee Kesler
model.
EOS Enthalpy Calculation
The Lee-Kesler enthalpies
may be slightly more accurate
for heavy hydrocarbon
systems, but require more
computer resources because
a separate model must be
solved.
With any the Equation of State options except ZJ and LKP, you can
specify whether the Enthalpy is calculated by either the Equation of
State method or the Lee Kesler method. The ZJ and LKP must use the
Lee Kesler method in Enthalpy calculations. Selection of an enthalpy
method is done by selecting radio buttons in the Enthalpy Method
group.
Figure A.1
Selecting the Lee Kesler Enthalpy option results in a combined property
package employing the appropriate equation of state (either PR or SRK)
for vapour-liquid equilibrium calculations and the Lee-Kesler equation
for calculation of enthalpies and entropies (for differences between EOS
and LK methods, refer to the Section A.4 - Enthalpy & Entropy
Departure Calculations).
The LK method yields comparable results to HYSYS’ standard equations
of state and has identical ranges of applicability. As such, this option
with PR has a slightly greater range of applicability than with SRK.
A-15
A-16
Property Methods
Zero Kij Option
This option is set on the
Binary Coeffs tab of the Fluid
Package property view.
HYSYS automatically generates hydrocarbon-hydrocarbon interaction
parameters when values are unknown if the Estimate HC-HC/Set Non
HC-HC to 0.0 radio button is selected. The Set All to 0.0 radio button
turns off the automatic calculation of any estimated interaction
coefficients between hydrocarbons. All binary interaction parameters
that are obtained from the pure component library remain.
Figure A.2
The Set All to 0.0 option may prove useful when trying to match results
from other commercial simulators which may not supply interaction
parameters for higher molecular weight hydrocarbons.
A.3.2 Activity Models
Although equation of state models have proven to be reliable in
predicting properties of most hydrocarbon based fluids over a large
range of operating conditions, their application is limited to primarily
non-polar or slightly polar components. Polar or non-ideal chemical
systems are traditionally handled using dual model approaches. In this
approach, an equation of state is used for predicting the vapour fugacity
coefficients (normally ideal gas assumption or the Redlich Kwong,
Peng-Robinson or SRK equations of state, although a Virial equation of
state is available for specific applications) and an activity coefficient
model is used for the liquid phase. Although there is considerable
research being conducted to extend equation of state applications into
the chemical arena (e.g., the PRSV equation), the state of the art of
property predictions for chemical systems is still governed mainly by
Activity Models.
A-16
Property Methods & Calculations
A-17
Activity Models are much more empirical in nature when compared to
the property predictions (equations of state) typically used in the
hydrocarbon industry. For example, they cannot be used as reliably as
the equations of state for generalized application or extrapolating into
untested operating conditions. Their tuning parameters should be fitted
against a representative sample of experimental data and their
application should be limited to moderate pressures. Consequently,
more caution should be exercised when selecting these models for your
simulation.
The phase separation or equilibrium ratio Ki for component i, defined in
terms of the vapour phase fugacity coefficient and the liquid phase
activity coefficient is calculated from the following expression:
Activity Models produce the
best results when they are
applied in the operating
region for which the
interaction parameters were
regressed.
yi
K i = ---xi
γi fi °
= ---------Pφ i
where:
(A.7)
γ i = liquid phase activity coefficient of component i
fi° = standard state fugacity of component i
P = system pressure
φ i = vapour phase fugacity coefficient of component i
Although for ideal solutions the activity coefficient is unity, for most
chemical (non-ideal) systems this approximation is incorrect.
Dissimilar chemicals normally exhibit not only large deviations from an
ideal solution, but the deviation is also found to be a strong function of
the composition. To account for this non-ideality, activity models were
developed to predict the activity coefficients of the components in the
liquid phase. The derived correlations were based on the excess Gibbs
energy function, which is defined as the observed Gibbs energy of a
mixture in excess of what it would be if the solution behaved ideally, at
the same temperature and pressure.
A-17
A-18
Property Methods
For a multi-component mixture consisting of ni moles of component i,
the total excess Gibbs free energy is represented by the following
expression:
G
where:
E
= RT ∑ ( n i ln γ i )
(A.8)
γ i is the activity coefficient for component i
The individual activity coefficients for any system can be obtained from
a derived expression for excess Gibbs energy function coupled with the
Gibbs-Duhem equation. The early models (Margules, van Laar) provide
an empirical representation of the excess function that limits their
application. The newer models such as Wilson, NRTL and UNIQUAC
utilize the local composition concept and provide an improvement in
their general application and reliability. All of these models involve the
concept of binary interaction parameters and require that they be fitted
to experimental data.
Since the Margules and van Laar models are less complex than the
Wilson, NRTL and UNIQUAC models, they require less CPU time for
solving flash calculations. However, these are older and more
empirically based models and generally give poor results for strongly
non-ideal mixtures such as alcohol-hydrocarbon systems, particularly
for dilute regions. The Chien-Null model provides the ability to
incorporate the different activity models within a consistent
thermodynamic framework. Each binary can be represented by the
model which best predicts its behaviour.
The following table briefly summarizes recommended models for
different applications (for a more detailed review, refer to the texts “The
Properties of Gases & Liquids”8 and “Molecular Thermodynamics of
Fluid Phase Equilibria” 9).
Application
A-18
Margules
van Laar
Wilson
NRTL
UNIQUAC
Binary Systems
A
A
A
A
A
Multicomponent Systems
LA
LA
A
A
A
Azeotropic Systems
A
A
A
A
A
Liquid-Liquid Equilibria
A
A
N/A
A
A
Dilute Systems
?
?
A
A
A
Self-Associating Systems
?
?
A
A
A
Property Methods & Calculations
Application
Margules
van Laar
Wilson
NRTL
UNIQUAC
Polymers
N/A
N/A
N/A
N/A
A
Extrapolation
?
?
G
G
G
A-19
A = Applicable; N/A = Not Applicable;? = Questionable; G = Good; LA = Limited Application
Vapour phase non-ideality can be taken into account for each activity
model by selecting the Redlich-Kwong, Peng-Robinson or SRK
equations of state as the vapour phase model. When one of the
equations of state is used for the vapour phase, the standard form of the
Poynting correction factor is always used for liquid phase correction. If
dimerization occurs in the vapour phase, the Virial equation of state
should be selected as the vapour phase model.
All of the binary parameters
in the HYSYS library are
regressed using an ideal
gas model for the vapour
phase.
The binary parameters required for the activity models are regressed
based on the VLE data collected from DECHEMA, Chemistry Data
Series3. There are over 16,000 fitted binary pairs in the HYSYS library.
The structures of all library components applicable for the UNIFAC VLE
estimation are also in the library. The Poynting correction for the liquid
phase is ignored if ideal solution behaviour is assumed.
HYSYS internally stored
binary parameters are NOT
regressed against three
phase equilibrium data.
If you are using the built-in binary parameters, the ideal gas model
should be used. All activity models, with the exception of the Wilson
equation, can automatically calculate three phases given the correct set
of energy parameters. The vapour pressures used in the calculation of
the standard state fugacity are based on the pure component
coefficients in HYSYS’ library using the modified form of the Antoine
equation.
When your selected components exhibit dimerization in the vapour
phase, the Virial option should be selected as the vapour phase model.
HYSYS contains fitted parameters for many carboxylic acids, and can
estimate values from pure component properties if the necessary
parameters are not available. Please refer to Section A.3.3 - Activity
Model Vapour Phase Options for a detailed description of the Virial
option.
A-19
A-20
Property Methods
General Remarks
The dual model approach for solving chemical systems with activity
models cannot be used with the same degree of flexibility and reliability
that the equations of state can be used for hydrocarbon systems.
However, some checks can be devised to ensure a good confidence level
in property predictions:
•
•
•
•
•
•
Please note that the activities
for the unknown binaries are
generated at pre-selected
compositions and the
supplied UNIFAC reference
temperature.
A-20
Check the property package selected for applicability for the
system considered and see how well it matches the pure
component vapour pressures. Although the predicted pure
component vapour pressures should normally be acceptable, the
parameters are fitted over a large temperature range. Improved
accuracies can be attained by regressing the parameters over
the desired temperature range.
The automatic UNIFAC generation of energy parameters in
HYSYS is a very useful tool and is available for all activity
models. However, it must be used with caution. The standard
fitted values in HYSYS likely produce a better fit for the binary
system than the parameters generated by UNIFAC. As a general
rule, use the UNIFAC generated parameters only as a last resort.
Always use experimental data to regress the energy parameters
when possible. The energy parameters in HYSYS are regressed
from experimental data, however, improved fits are still possible
by fitting the parameters for the narrow operating ranges
anticipated. The regressed parameters are based on data taken
at atmospheric pressures. Exercise caution when extrapolating to
higher or lower pressure (vacuum) applications.
Check the accuracy of the model for azeotropic systems.
Additional fitting may be required to match the azeotrope with
acceptable accuracy. Check not only for the temperature, but for
the composition as well.
If three phase behaviour is suspected, additional fitting of the
parameters may be required to reliably reproduce the VLLE
equilibrium conditions.
An improvement in matching equilibrium data can be attained by
including a temperature dependency of the energy parameters.
However, depending on the validity or range of fit, this can lead to
misleading results when extrapolating beyond the fitted
temperature range.
By default, HYSYS regresses ONLY the aij parameters while the bij
parameters are set to zero, i.e., the aij term is assumed to be
temperature independent. A temperature dependency can be
incorporated by supplying a value for the bij term. The matrix for the bij
values are displayed by selecting the Bij radio button to switch matrices
(note the zero or blank entries for all the binary pairs).
Property Methods & Calculations
A-21
When using the NRTL, General NRTL or Extended NRTL equations,
more than two matrices are available. In general, the second matrix is
the Bij matrix, and the third matrix is the αij parameter where αij = αji.
Any component pair with an aij value has an associated α value.
Immiscible
The Wilson equation does not
support LLE equilibrium.
This option is included for modeling the solubility of solutes in two
coexisting liquid phases that are relatively immiscible with one another,
such as a H2O-hydrocarbon system. In this system, the hydrocarbon
components (solutes) are relatively insoluble in the water phase
(solvent) whereas the solubility of the H2O in the hydrocarbon phase
can become more significant. The limited mutual solubility behaviour
can be taken into account when using any activity model with the
exception of Wilson.
This feature can be implemented for any single component pair by
using the Immiscible radio button. Component i is insoluble with
component j, based on the highlighted cell location. Alternatively, you
can have all j components treated as insoluble with component i.
HYSYS replaces the standard binary parameters with those regressed
specifically for matching the solubilities of the solutes in both phases.
Note that both the aij and bij parameters are regressed with this option.
These parameters were regressed from the mutual solubility data of nC5, n-C6, n-C7, and n-C8 in H2O over a temperature range of 313 K to 473
K.
The solubility of H2O in the hydrocarbon phase and the solubility of the
hydrocarbons in the water phase are calculated based on the fitted
binary parameters regressed from the solubility data referenced above.
Chien-Null
The Chien Null model provides a consistent framework for applying
existing activity models on a binary by binary basis. In this manner, the
Chien Null model allows you to select the best activity model for each
pair in the case.
A-21
A-22
Property Methods
The Chien Null model allows three sets of coefficients for each
component pair, accessible through the A, B and C coefficient matrices.
Please refer to the following sections for an explanation of the terms for
each of the models.
Chien Null Form
The Chien-Null generalized multi-component equation can be
expressed as follows:
2 ln Γ i
L






 ∑ A j, k x j   ∑ R j, k x j 
 ∑ A j, i x j   ∑ R j, i x j 






j
j
j
j
= -------------------------------------------------------- + ∑ x k ------------------------------------------------------------- ⋅






k
 ∑ S j, k x j  ∑ V j, k x j
 ∑ S j, i x j  ∑ V j, i x j






j
j
j
j
(A.9)
A i, k
R i, k
S i, k
V i, k
----------------------- + ----------------------- – ---------------------- – ----------------------∑ Aj, k xj ∑ Rj, k xj ∑ Sj, k xj ∑ Vj, k xj
j
j
j
j
Each of the parameters in this equation are defined specifically for each
of the applicable activity methods.
Description of Terms
The Regular Solution equation uses the following:
L
2
vi ( δi – δj )
A i, j = ---------------------------RT
A i, j
R i, j = -------A j, i
V i, j = R i, j
S i, j = R i, j
(A.10)
δi is the solubility parameter in (cal/cm3)½ and viL is the saturated liquid
volume in cm3/mol calculated from:
L
v i = v ω, i ( 5.7 + 3T r, i )
A-22
(A.11)
Property Methods & Calculations
A-23
The van Laar, Margules and Scatchard Hamer use the following:
Model
Ai,j
Ri,j
∞
ln γ i, j
van Laar
Margules
∞
2 ln γ i, j
------------------------------∞
 ln γ i, j 
1 +  ---------------
 ln γ j∞

,i
Scatchard Hamer
Si,j
A i, j
-------A j, i
R i, j
R i, j
A i, j
-------A j, i
1
1
A i, j
-------A j, i
vi
----∞
vj
∞
2 ln γ i, j
------------------------------∞
 ln γ i, j 
---------------1+

 ln γ j∞

,i
Vi,j
∞
∞
vi
----∞
vj
For the van Laar, Margules and Scatchard Hamer equations:
b i, j
∞
ln γ i, j = a i, j + -------- + c ij T
T
where:
If you have regressed
parameters using HYPROP
for any of the Activity Models
supported under the Chien
Null, they are not read in.
(A.12)
T = temperature unit must be in K
Note that this equation is of a different form than the original van Laar
and Margules equations in HYSYS, which uses an a + bT relationship.
However, since HYSYS only contains aij values, the difference should
not cause problems.
The NRTL form for the Chien Null uses:
A i, j = 2τ i, j V i, j
R i, j = 1
V i, j = exp ( – c i, j τ i, j )
S i, j = 1
b i, j
τ i, j = a i, j + -----------T(K)
(A.13)
The expression for the τ term under the Chien Null incorporates the R
term of HYSYS’ NRTL into the values for aij and bij. As such, the values
initialized for NRTL under Chien Null are not the same as for the regular
NRTL. When you select NRTL for a binary pair, aij is empty (essentially
equivalent to the regular NRTL bij term), bij is initialized and cij is the α
term for the original NRTL, and is assumed to be symmetric.
A-23
A-24
Property Methods
The General Chien Null equation is:
b i, j
A i, j = a i, j + -----------T(K)
A i, j
R i, j = -------A j, i
V i, j = C i, j
S i, j = C i, j
(A.14)
In all cases:
A i, i = 0
R i, i = S i, i = V i, i = 1
(A.15)
With the exception of the Regular Solution option, all models can utilize
six constants, ai,j, aj,i, bi,j, bj,i, ci,j and cj,i for each component pair. For all
models, if the constants are unknown they can be estimated internally
from the UNIFAC VLE or LLE methods, the Insoluble option, or using
Henry’s Law coefficients for appropriate components. For the general
Chien Null model, the cij’s are assumed to be 1.
Extended & General NRTL
The Extended and General NRTL models are variations of the NRTL
model. More binary interaction parameters are used in defining the
component activity coefficients. You may apply either model to
systems:
•
•
A-24
with a wide boiling point range between components.
where you require simultaneous solution of VLE and LLE, and
there exists a wide boiling point range or concentration range
between components.
Property Methods & Calculations
The equations options can be
viewed in the Display Form
drop-down list on the Binary
Coeffs tab of the Fluid
Package property view.
A-25
You can specify the format for the Equations of τij and aij to be any of
the following:
τij and αij Options
B ij C ij
τ ij = A ij + ------ + ------2- + F ij T + G ij ln ( T )
T
T
α ij = Alp1 ij + Alp2 ij T
τ ij
B ij
A ij + -----T
= -------------------RT
α ij = Alp1 ij
B ij
τ ij = A ij + ------ + F ij T + G ij ln ( T )
T
α ij = Alp1 ij + Alp2 ij T
C ij
τ ij = A ij + B ij t + ------T
α ij = Alp1 ij + Alp2 ij T
where: T is in K and t is °C
B ij
τ ij = A ij + -----T
α ij = Alp1 ij
Depending on which form of the equations that you have selected, you
are able to specify values for the different component energy
parameters. The General NRTL model provides radio buttons on the
Binary Coeffs tab which access the matrices for the Aij, Bij, Cij, Fij, Gij,
Alp1ij and Alp2ij energy parameters.
The Extended NRTL model allows you to input values for the Aij, Bij, Cij,
Alp1ij and Alp2ij energy parameters by selecting the appropriate radio
button. You do not have a choice of equation format for τij and αij. The
following is used:
C ij
τ ij =  A ij + B ij t + -------

T
(A.16)
α ij = Alp1 ij + Alp2 ij
A-25
A-26
Property Methods
where:
T = temperature in K
t = temperature in °C
Margules
The equation should not be
used for extrapolation beyond
the range over which the
energy parameters are fitted.
The Margules equation was the first Gibbs excess energy representation
developed. The equation does not have any theoretical basis, but is
useful for quick estimates and data interpolation. HYSYS has an
extended multicomponent Margules equation with up to four
adjustable parameters per binary.
The four adjustable parameters for the Margules equation in HYSYS are
the aij and aji (temperature independent) and the bij and bji terms
(temperature dependent). The equation uses parameter values stored in
HYSYS or any user supplied value for further fitting the equation to a
given set of data.
The Margules activity coefficient model is represented by the following
equation:
2
ln γ i = [ 1.0 – x i ] [ A i + 2x i ( B i – A i ) ]
where:
(A.17)
γ i = activity coefficient of component i
xi = mole fraction of component i
n
Ai =
( a ij + b ij T )
∑ xj -------------------------( 1.0 – x i )
j=1
n
Bi =
( a ji + b ji T )
∑ xj -------------------------( 1.0 – x i )
j=1
T = temperature (K)
n = total number of components
aij = non-temperature dependent energy parameter between
components i and j
bij = temperature dependent energy parameter between components i
and j [1/K]
A-26
Property Methods & Calculations
A-27
aji = non-temperature dependent energy parameter between
components j and i
bji = temperature dependent energy parameter between components j
and i [1/K]
NRTL
The NRTL (Non-Random-Two-Liquid) equation, proposed by Renon
and Prausnitz in 1968, is an extension of the original Wilson equation. It
uses statistical mechanics and the liquid cell theory to represent the
liquid structure. These concepts, combined with Wilson’s local
composition model, produce an equation capable of representing VLE,
LLE and VLLE phase behaviour.
Like the Wilson equation, the NRTL is thermodynamically consistent
and can be applied to ternary and higher order systems using
parameters regressed from binary equilibrium data. It has an accuracy
comparable to the Wilson equation for VLE systems.
Unlike the van Laar equation,
NRTL can be used for dilute
systems and hydrocarbonalcohol mixtures, although it
may not be as good for
alcohol-hydrocarbon systems
as the Wilson equation.
The NRTL equation in HYSYS contains five adjustable parameters
(temperature dependent and independent) for fitting per binary pair.
The NRTL combines the advantages of the Wilson and van Laar
equations, and, like the van Laar equation, it is not extremely CPU
intensive and can represent LLE quite well. It is important to note that
because of the mathematical structure of the NRTL equation, it can
produce erroneous multiple miscibility gaps.
The NRTL equation in HYSYS has the following form:


n


τ
x
G
mj
m
mj
∑


n
G
x

j=1
m=1
j ij 
ln γ i = ---------------------------- + ∑ ------------------------  τ ij – ------------------------------------
n
n
n


j=1

x
G
x
G
x
G
∑ k kj 
∑ k ki
∑ k kj 


k=1
k=1
k=1
n
∑ τji xj Gji
where:
(A.18)
γ i = activity coefficient of component i
Gij = exp [ – τ ij α ij ]
A-27
A-28
Property Methods
a ij + b ij T
τ ij = ---------------------RT
xi = mole fraction of component i
T = temperature (K)
n = total number of components
aij = non-temperature dependent energy parameter between
components i and j (cal/gmol)
bij = temperature dependent energy parameter between components i
and j (cal/gmol-K)
α ij = NRTL non-randomness constant for binary interaction note that
α ij = α ji for all binaries
The five adjustable parameters for the NRTL equation in HYSYS are the
aij, aji, bij, bji, and α ij terms. The equation uses parameter values stored
in HYSYS or any user supplied value for further fitting the equation to a
given set of data.
UNIQUAC
The UNIQUAC (UNIversal QUAsi Chemical) equation proposed by
Abrams and Prausnitz in 1975 uses statistical mechanics and the quasichemical theory of Guggenheim to represent the liquid structure. The
equation is capable of representing LLE, VLE and VLLE with accuracy
comparable to the NRTL equation, but without the need for a nonrandomness factor. The UNIQUAC equation is significantly more
detailed and sophisticated than any of the other activity models. Its
main advantage is that a good representation of both VLE and LLE can
be obtained for a large range of non-electrolyte mixtures using only two
adjustable parameters per binary. The fitted parameters usually exhibit
a smaller temperature dependence which makes them more valid for
extrapolation purposes.
The UNIQUAC equation utilizes the concept of local composition as
proposed by Wilson. Since the primary concentration variable is a
surface fraction as opposed to a mole fraction, it is applicable to systems
containing molecules of very different sizes and shape, such as polymer
solutions. The UNIQUAC equation can be applied to a wide range of
mixtures containing H2O, alcohols, nitriles, amines, esters, ketones,
aldehydes, halogenated hydrocarbons and hydrocarbons.
A-28
Property Methods & Calculations
A-29
HYSYS contains the following four-parameter extended form of the
UNIQUAC equation. The four adjustable parameters for the UNIQUAC
equation in HYSYS are the aij and aji terms (temperature independent),
and the bij and bji terms (temperature dependent). The equation uses
parameter values stored in HYSYS or any user supplied value for further
fitting the equation to a given set of data.
Φi
θi
Φi
ln γ i = ln  ------ + 0.5Zq i ln  ------ + L i –  ------
 xi 
 Φ i
 xi 
where:
n


 1.0 – ln
L
x
+
q
θ
τ
∑ j j i
∑ j ji


j=1
j=1
n




n  θ τ

j ij
– q i ∑  -----------------------
 n


j = 1
 ∑ θ k τ kj
 k=1

(A.19)
γ i = activity coefficient of component i
xi = mole fraction of component i
T = temperature (K)
n = total number of components
Lj = 0.5Z(rj-qj)-rj+1
qi xi
θ i = ---------------∑ qj xj
j
a ij + b ij T
τ ij = exp – ---------------------RT
ri xi
Φ i = --------------∑ rj xj
j
Z = 10.0 co-ordination number
aij = non-temperature dependent energy parameter between
components i and j (cal/gmol)
bij = temperature dependent energy parameter between components i
and j (cal/gmol-K)
qi = van der Waals area parameter - Awi /(2.5e9)
Aw = van der Waals area
ri = van der Waals volume parameter - Vwi /(15.17)
Vw = van der Waals volume
A-29
A-30
Property Methods
Van Laar
The van Laar equation was the first Gibbs excess energy representation
with physical significance. The van Laar equation in HYSYS is a
modified form of that described in “Phase Equilibrium in Process
Design” by H.R. Null. This equation fits many systems quite well,
particularly for LLE component distributions. It can be used for systems
that exhibit positive or negative deviations from Raoult's Law, however,
it cannot predict maxima or minima in the activity coefficient.
Therefore, it generally performs poorly for systems with halogenated
hydrocarbons and alcohols. Due to the empirical nature of the equation,
caution should be exercised in analyzing multi-component systems. It
also has a tendency to predict two liquid phases when they do not exist.
The van Laar equation also
performs poorly for dilute
systems and cannot represent
many common systems, such
as alcohol-hydrocarbon
mixtures, with acceptable
accuracy.
The van Laar equation has some advantages over the other activity
models in that it requires less CPU time and can represent limited
miscibility as well as three phase equilibrium. HYSYS uses the following
extended, multi-component form of the van Laar equation.
2
ln γ i = A i [ 1.0 – z i ] ( 1.0 + E i z i )
where:
γ i = activity coefficient of component i
xi = mole fraction of component i
n
Ai =
∑
j =1
n
Bi =
∑
j=1
( a ij + b ij T )
x j --------------------------( 1.0 – x i )
( a ji + b ji T )
x j --------------------------( 1.0 – x i )
Ei = -4.0 if Ai and Bi < 0.0, otherwise 0.0
Ai xi
zi = ------------------------------------------------[ A i x i + B i ( 1.0 – x i ) ]
T = temperature (K)
n = total number of components
aij = non-temperature dependent energy parameter between
components i and j
A-30
(A.20)
Property Methods & Calculations
A-31
bij = temperature dependent energy parameter between components i
and j [1/K]
aji = non-temperature dependent energy parameter between
components j and i
bji = temperature dependent energy parameter between components j
and i [1/K]
The four adjustable parameters for the van Laar equation in HYSYS are
the aij, aji, bij, and bji terms. The equation will use parameter values
stored in HYSYS or any user supplied value for further fitting the
equation to a given set of data.
Wilson
The Wilson equation cannot
be used for problems involving
liquid-liquid equilibrium.
The Wilson equation, proposed by Grant M. Wilson in 1964, was the first
activity coefficient equation that used the local composition model to
derive the Gibbs Excess energy expression. It offers a
thermodynamically consistent approach to predicting multicomponent behaviour from regressed binary equilibrium data. Our
experience also shows that the Wilson equation can be extrapolated
with reasonable confidence to other operating regions with the same set
of regressed energy parameters.
Although the Wilson equation is more complex and requires more CPU
time than either the van Laar or Margules equations, it can represent
almost all non-ideal liquid solutions satisfactorily except electrolytes
and solutions exhibiting limited miscibility (LLE or VLLE). It performs
an excellent job of predicting ternary equilibrium using parameters
regressed from binary data only.
The Wilson equation gives similar results as the Margules and van Laar
equations for weak non-ideal systems, but consistently outperforms
them for increasingly non-ideal systems.
Setting all four parameters to
zero does not reduce the
binary to an ideal solution, but
maintains a small effect due to
molecular size differences
represented by the ratio of
molar volumes.
The Wilson equation in HYSYS requires two to four adjustable
parameters per binary. The four adjustable parameters for the Wilson
equation in HYSYS are the aij and aji (temperature independent) terms,
and the bij and bji terms (temperature dependent). Depending upon the
available information, the temperature dependent parameters may be
set to zero.
A-31
A-32
Property Methods
Although the Wilson equation contains terms for temperature
dependency, caution should be exercised when extrapolating. The
Wilson activity model in HYSYS has the following form:
n
∑
ln γ i = 1.0 – ln
n
x j A ij –
j=1
∑
x k A ki
----------------------
k=1
∑ xj Akj
n
(A.21)
j=1
where:
γ i = activity coefficient of component i
Vj
( a ij + b ij T )
Aij = ----- exp – --------------------------Vi
RT
xi = mole fraction of component i
T = temperature (K)
n = total number of components
aij = non-temperature dependent energy parameter between
components i and j (cal/gmol)
bij = temperature dependent energy parameter between components i
and j (cal/gmol-K)
Vi = molar volume of pure liquid component i in m3/kgmol (litres/
gmol)
The equation uses parameter values stored in HYSYS or any user
supplied value for further fitting the equation to a given set of data.
Henry’s Law
Henry’s Law cannot be selected explicitly as a property method in
HYSYS. However, HYSYS uses Henry’s Law when an activity model is
selected and "non-condensable" components are included within the
component list.
A-32
Property Methods & Calculations
A-33
HYSYS considers the following components "non-condensable":
Component
Simulation Name
CH4
Methane
C2H6
Ethane
C2H4
Ethylene
C2H2
Acetylene
H2
Hydrogen
He
Helium
Ar
Argon
N2
Nitrogen
O2
Oxygen
NO
NO
H2S
H2S
CO2
CO2
CO
CO
The extended Henry’s Law equation in HYSYS is used to model dilute
solute/solvent interactions. "Non-condensable" components are
defined as those components that have critical temperatures below the
temperature of the system you are modeling. The equation has the
following form:
B
ln H ij = A + --- + C ln ( T ) + DT
T
where:
(A.22)
i = solute or "non-condensable" component
j = solvent or condensable component
Hij = Henry’s coefficient between i and j in kPa
A = A coefficient entered as aij in the parameter matrix
B = B coefficient entered as aji in the parameter matrix
C = C coefficient entered as bij in the parameter matrix
D = D coefficient entered as bji in the parameter matrix
T = temperature in degrees K
A-33
A-34
Property Methods
An example of the use of Henry’s Law coefficients is illustrated below.
The NRTL activity model is selected as the property method. There are
three components in the Fluid Package, one of which, ethane, is a "noncondensable" component. On the Binary Coeffs tab of the Fluid Package
property view, you can view the Henry’s Law coefficients for the
interaction of ethane and the other components.
By selecting the Aij radio button, you can view/edit the A and B
coefficients. Select the Bij radio button to enter or view the C and D
coefficients in the Henry’s Law equation.
Figure A.3
C2 is a "non-condensable"
component. Henry’s Law is
used for the interaction
between C2 and the other
components in the Fluid
Package.
HYSYS does not
contain a pre-fitted
Henry’s Law A
coefficient for the
ethane/ethanol
pair. You can
estimate it or
provide your own
value.
Henry’s Law B
coefficient for the
interaction between
C2 and H2O.
Henry’s Law
A coefficient
for the
interaction
between C2
and H2O.
Normal
binary
interaction
coefficient for
the H2O/
Ethanol pair.
Henry’s Law D
coefficient for the
interaction between
C2 and H2O.
Henry’s Law C
coefficient for the
interaction
between C2 and
H2O.
If HYSYS does not contain pre-fitted Henry’s Law coefficients and
Henry’s Law data is not available, HYSYS estimates the missing
coefficients. To estimate a coefficient (A or B in this case), select the Aij
radio button, highlight a binary pair and press the Individual Pair
button. The coefficients are regressed to fugacities calculated using the
Chao-Seader/Prausnitz-Shair correlations for standard state fugacity
and Regular Solution. To supply your own coefficients you must enter
them directly into the Aij and Bij matrices, as shown previously.
No interaction between "non-condensable" component pairs is taken
into account in the VLE calculations.
A-34
Property Methods & Calculations
A-35
A.3.3 Activity Model Vapour Phase Options
There are several models available for calculating the Vapour Phase in
conjunction with the selected liquid activity model. The selection
depends on specific considerations of your system. However, in cases
when you are operating at moderate pressures (less than 5 atm),
selecting Ideal Gas should be satisfactory. The choices are described in
the following sections:
Ideal
The ideal gas law is used to model the vapour phase. This model is
appropriate for low pressures and for a vapour phase with little
intermolecular interaction.
Peng Robinson, SRK or RK
To model non-idealities in the vapour phase, the PR, SRK or RK options
can be used in conjunction with an activity model. The PR and SRK
vapour phase models handle the same types of situations as the PR and
SRK equations of state (refer to Section A.3.1 - Equations of State).
When selecting one of these options (PR, SRK or RK) as the vapour
phase model, you must ensure that the binary interaction parameters
used for the activity model remain applicable with the selected vapour
model. You must keep in mind that all the binary parameters in the
HYSYS Library are regressed using the ideal gas vapour model.
For applications where you have compressors or turbines being
modeled within your Flowsheet, PR or SRK is superior to either the RK
or ideal vapour model. You obtain more accurate horsepower values by
using PR or SRK, as long as the light components within your Flowsheet
can be handled by the selected vapour phase model (i.e., C2H4 or C3H6
are fine, but alcohols are not modeled correctly).
A-35
A-36
Property Methods
Virial
The Virial option enables you to better model vapour phase fugacities of
systems displaying strong vapour phase interactions. Typically this
occurs in systems containing carboxylic acids, or compounds that have
the tendency to form stable H2 bonds in the vapour phase. In these
cases, the fugacity coefficient shows large deviations from ideality, even
at low or moderate pressures.
HYSYS contains temperature dependent coefficients for carboxylic
acids. You can overwrite these by changing the Association (ii) or
Solvation (ij) coefficients from the default values.22
If the virial coefficients need to be calculated, HYSYS contains
correlations using the following pure component properties:
•
•
•
•
•
•
critical temperature
critical pressure
dipole moment
mean radius of gyration
association parameter
association parameter for each binary pair
This option is restricted to systems where the density is moderate,
typically less than one-half the critical density. The Virial equation used
is valid for the following range:
m
∑ yi Pc
i
T i=1
P ≤ --- -------------------2 m
∑ yi Tc
i
i=1
A-36
(A.23)
Property Methods & Calculations
A-37
A.3.4 Semi-Empirical Methods
The Chao-Seader10 and Grayson-Streed11 methods are older, semiempirical methods. The GS correlation is an extension of the CS method
with special emphasis on H2. Only the equilibrium results produced by
these correlations is used by HYSYS. The Lee-Kesler method is used for
liquid and vapour enthalpies and entropies as its results are shown to be
superior to those generated from the CS/GS correlations. This method is
also adopted by and recommended for use in the API Technical Data
Book.
The following table gives an approximate range of applicability for these
two methods, and under what conditions they are applicable.
Method
Temp. (°C)
Temp. (°C)
Press. (psia)
Press. (kPa)
CS
0 to 500
18 to 260
<1,500
<10,000
GS
0 to 800
18 to 425
<3,000
<20,000
Conditions of Applicability
For all hydrocarbons (except CH4):
If CH4 or H2 is present:
0.5<Tri<1.3 and Prmixture <0.8
• molal average Tr <0.93
• CH4 mole fraction <0.3
• mole fraction dissolved gases <0.2
When predicting K values for:
Paraffinic or Olefinic Mixtures
liquid phase aromatic mole fraction <0.5
Aromatic Mixtures
liquid phase aromatic mole fraction >0.5
The GS correlation is recommended for simulating heavy hydrocarbon
systems with a high H2 content, such as hydrotreating units. The GS
correlation can also be used for simulating topping units and heavy
ends vacuum applications.
The vapour phase fugacity coefficients are calculated with the Redlich
Kwong equation of state. The pure liquid fugacity coefficients are
calculated using the principle of corresponding states. Modified
acentric factors are included in HYSYS’ GS library for most components.
Special functions are incorporated for the calculation of liquid phase
fugacities for N2, CO2 and H2S. These functions are restricted to
hydrocarbon mixtures with less than five percent of each of the above
components.
A-37
A-38
Property Methods
As with the Vapour Pressure models, H2O is treated using a combination
of the steam tables and the kerosene solubility charts from the API Data
Book. This method of handling H2O is not very accurate for gas systems.
Although three phase calculations are performed for all systems, it is
important to note that the aqueous phase is always treated as pure H2O
with these correlations.
A.3.5 Vapour Pressure Property Packages
Vapour pressure K value models may be used for ideal mixtures at low
pressures. This includes hydrocarbon systems such as mixtures of
ketones or alcohols where the liquid phase behaves approximately
ideal. The models may also be used for first approximations for nonideal systems.
The Lee-Kesler model is used for enthalpy and entropy calculations for
all vapour pressure models and all components with the exception of
H2O, which is treated separately with the steam property correlation.
All three phase calculations are performed assuming the aqueous phase
is pure H2O and that H2O solubility in the hydrocarbon phase can be
described using the kerosene solubility equation from the API Data
Book (Figure 9A1.4).
Because all of the Vapour
Pressure options assume an
ideal vapour phase, they are
classified as Vapour Pressure
Models.
Vapour pressures used in the calculation of the standard state fugacity
are based on HYSYS’ library coefficients and a modified form of the
Antoine equation. Vapour pressure coefficients for hypocomponent
may be entered or calculated from either the Lee-Kesler correlation for
hydrocarbons, the Gomez-Thodos correlation for chemical compounds
or the Reidel equation.
The Vapour Pressure options include the Modified Antoine, BraunK10,
and EssoK packages.
Approximate ranges of application for each vapour pressure model are
given below:
A-38
Model
Temperature
Press. (psia)
Press. (kPa)
Mod. Antoine
<1.6 Tci
<100
<700
BraunK10
0°F (-17.78°C) <1.6 Tci
<100
<700
EssoK
<1.6 Tci
<100
<700
Property Methods & Calculations
A-39
Modified Antoine Vapour Pressure Model
The modified Antoine equation assumes the form as set out in the
DIPPR data bank.
F
B
ln P vap = A + ------------- + D ln T + ET
T+C
where:
(A.24)
A, B, C, D, E and F = fitted coefficients
Pvap = the pressure in kPa
T = the temperature in K
All enthalpy and entropy
calculations are performed
using the Lee-Kesler model.
These coefficients are available for all HYSYS library components.
Vapour pressure coefficients for hypocomponent may be entered or
calculated from either the Lee-Kesler correlation for hydrocarbons, the
Gomez-Thodos correlation for chemical compounds, or the Reidel
equation.
This model is applicable for low pressure systems that behave ideally.
For hydrocarbon components that you have not provided vapour
pressure coefficients for, the model converts the Lee-Kesler vapour
pressure model directly. As such, crude and vacuum towers can be
modeled with this equation.
When using this method for super-critical components, it is
recommended that the vapour pressure coefficients be replaced with
Henry’s Law coefficients. Changing Vapour Pressure coefficients can
only be accomplished if your component is being installed as a
Hypothetical.
A-39
A-40
Property Methods
Braun K10 Model
The Braun K10 model is strictly applicable to heavy hydrocarbon
systems at low pressures. The model employs the Braun convergence
pressure method, where, given the normal boiling point of a
component, the K value is calculated at system temperature and 10 psia.
The K10 value is then corrected for pressure using pressure correction
charts. The K values for any components that are not covered by the
charts are calculated at 10 psia using the modified Antoine equation and
corrected to system conditions using the pressure correction charts.
The Lee-Kesler model is
used for enthalpy and entropy
calculations for all
components with the
exception of H2O which is
treated with the steam tables.
Accuracy suffers with this model if there are large amounts of acid gases
or light hydrocarbons. All three phase calculations assume that the
aqueous phase is pure H2O and that H2O solubility in the hydrocarbon
phase can be described using the kerosene solubility equation from the
API Data Book (Figure 9A1.4).
Esso K Model
The Esso Tabular model is strictly applicable to hydrocarbon systems at
low pressures. The model employs a modification of the MaxwellBonnel vapour pressure model in the following format:
log P vap =
where:
∑ Ai x
i
Ai = fitted constants
i
Tb
i
----- – 0.0002867T b
i
T
x = -------------------------------------------i
748.1 – 0.2145T b
Tbi = normal boiling point corrected to K = 12
T = absolute temperature
K = Watson characterisation factor
A-40
(A.25)
Property Methods & Calculations
Note that the Lee-Kesler
model is used for enthalpy and
entropy calculations for all
components with the
exception of H2O which is
treated with the steam tables.
A-41
For heavy hydrocarbon systems, the results are comparable to the
modified Antoine equation since no pressure correction is applied. For
non-hydrocarbon components, the K value is calculated using the
Antoine equation. Accuracy suffers if there is a large amount of acid
gases or light hydrocarbons. All three phase calculations are performed
assuming the aqueous phase is pure H2O and that H2O solubility in the
hydrocarbon phase can be described using the kerosene solubility
equation from the API Data Book (Figure 9A1.4).
A.3.6 Miscellaneous - Special Application
Methods
Amines Property Package
For the Amine property
method, the vapour phase is
modeled using the PR model.
The amines package contains the thermodynamic models developed by
D.B. Robinson & Associates for their proprietary amine plant simulator,
called AMSIM. Their amine property package is available as an option
with HYSYS giving you access to a proven third party property package
for reliable amine plant simulation, while maintaining the ability to use
HYSYS’ powerful flowsheeting capabilities.
The chemical and physical property data base is restricted to amines
and the following components:
This method does not allow
any hypotheticals.
Component Class
Specific Components
Acid Gases
CO2, H2S, COS, CS2
Hydrocarbons
CH4 C7H16
Olefins
C2=, C3=
Mercaptans
M-Mercaptan, E-Mercaptan
Non Hydrocarbons
H2, N2, O2, CO, H2O
The equilibrium acid gas solubility and kinetic parameters for the
aqueous alkanolamine solutions in contact with H2S and CO2 are
incorporated into their property package. The amines property package
is fitted to extensive experimental data gathered from a combination of
D.B. Robinson’s in-house data, several unpublished sources, and
numerous technical references.
A-41
A-42
Property Methods
The following table gives the equilibrium solubility limitations that
should be observed when using this property package:
Alkanolamine
Alkanolamine
Concentration (wt%)
Acid Gas Partial
Pressure (psia)
Temperature
(°F)
Monoethanolamine, MEA
0 - 30
0.00001 - 300
77 - 260
Diethanolamine, DEA
0 - 50
0.00001 - 300
77 - 260
Triethanolamine, TEA
0 - 50
0.00001 - 300
77 - 260
Methyldiethanolamine, MDEA*
0 - 50
0.00001 - 300
77 - 260
Diglycolamine, DGA
50 - 70
0.00001 - 300
77 - 260
DIsoPropanolAmine, DIsoA
0 - 40
0.00001 - 300
77 - 260
* The amine mixtures, DEA/MDEA and MEA/MDEA are assumed to be primarily MDEA, so
use the MDEA value for these mixtures.
It is important to note that data is not correlated for H2S and CO2
loadings greater than 1.0 mole acid gas/mole alkanolamine.
The absorption of H2S and CO2 by aqueous alkanolamine solutions
involves exothermic reactions. The heat effects are an important factor
in amine treating processes and are properly taken into account in the
amines property package. Correlations for the heats of solution are set
up as a function of composition and amine type. The correlations were
generated from existing published values or derived from solubility data
using the Gibbs-Helmholtz equation.
The amines package incorporates a specialized stage efficiency model to
permit simulation of columns on a real tray basis. The stage efficiency
model calculates H2S and CO2 component stage efficiencies based on
the tray dimensions given and the calculated internal tower conditions
for both absorbers and strippers. The individual component stage
efficiencies are a function of pressure, temperature, phase
compositions, flow rates, physical properties, mechanical tray design
and dimensions as well as kinetic and mass transfer parameters.
Since kinetic and mass transfer effects are primarily responsible for the
H2S selectivity demonstrated by amine solutions, this must be
accounted for by non unity stage efficiencies. See Chapter 8 - Column of
the Operations guide for details on how to specify or have HYSYS
calculate the stage efficiencies.
A-42
Property Methods & Calculations
A-43
Steam Package
HYSYS includes two steam packages:
•
•
ASME Steam
NBS Steam
Both of these property packages are restricted to a single component,
namely H2O.
ASME Steam accesses the ASME 1967 steam tables. The limitations of
this steam package are the same as those of the original ASME steam
tables, i.e., pressures less than 15,000 psia and temperatures greater
than 32°F (0°C) and less than 1,500°F.
The basic reference is the book “Thermodynamic and Transport
Properties of Steam” - The American Society of Mechanical Engineers Prepared by C.A. Meyer, R.B. McClintock, G.J. Silvestri and R.C. Spencer
Jr.20
Selecting NBS_Steam uses the NBS 1984 Steam Tables, which reportedly
has better calculations near the Critical Point.
MBWR
In HYSYS, a 32-term modified BWR equation of state is used. The
modified BWR may be written in the following form:
32
P = RTρ +
∑ Ni Xi
(A.26)
i=1
A-43
A-44
Property Methods
where:
X1 = ρ2T
X8 = ρ3/T
X15 = ρ6/T2
X22 = ρ5F/T2
X29 = ρ11F/T3
X2 = ρ T
X9 = ρ /T2
X16 = ρ /T
X23 = ρ F/T
4
X30 = ρ13F/T2
X3 = ρ2
X10 = ρ4T
X17 = ρ8/T
X4 = ρ /T
X11 = ρ
X18 = ρ /T
2 1/2
2
X5 = ρ /T
3
4
7
8
5
X24 = ρ7F/T2
X31 = ρ13F/T3
2
X25 = ρ F/T
3
X32 = ρ13F/T4
2
7
X12 = ρ /T
X19 = ρ /T2
X26 = ρ F/T
X6 = ρ3T
X13 = ρ5
X20 = ρ3F/T2
X27 = ρ9F/T4
X7 = ρ3
X14 = ρ6/T
X21 = ρ3F/T3
X28 = ρ11F/T2
2
2
4
9
9
F = exp (-0.0056 r2)
The modified BWR is applicable only for the following pure
components:
Note that mixtures of different
forms of H2 are also
acceptable. The range of use
for these components is
shown in this table.
A-44
Component
Temp. (K)
Temp. (R)
Max. Press.
(MPa)
Max. Press.
(psia)
Ar
84 - 400
151.2 - 720
100
14,504
CH4
91 - 600
163.8 - 1,080
200
29,008
C2H4
104 - 400
187.2 - 720
40
5,802
C2H6
90 - 600
162. - 1,080
70
10,153
C3H8
85 - 600
153. - 1080
100
14,504
i-C4
114 - 600
205.2 - 1,080
35
5,076
n-C4
135 - 500
243. - 900
70
10,153
CO
68 - 1,000
122.4 - 1,800
30
4,351
CO2
217 - 1,000
390.6 - 1,800
100
14,504
D2
29 - 423
52.2 - 761.4
320
46,412
H2
14 - 400
25.2 - 720
120
17,405
o-H2
14 - 400
25.2 - 720
120
17,405
p-H2
14 - 400
25.2 - 720
120
17,405
He
0.8 - 1,500
1.4 - 2,700
200
29,008
N2
63 - 1,900
113.4 - 3,420
1,000
145,038
O2
54 - 400
97.2 - 720
120
17,405
Xe
161 - 1,300
289.8 - 2,340
100
14,504
Property Methods & Calculations
A-45
A.4 Enthalpy & Entropy Departure
Calculations
With semi-empirical and
vapour pressure models, a
pure liquid water phase is
generated and the solubility of
H2O in the hydrocarbon phase
is determined from the
kerosene solubility model.
The Enthalpy and Entropy calculations are performed rigorously by
HYSYS using the following exact thermodynamic relations:
ID
V
1
∂P
H–H
-------------------- = Z – 1 + ------- ∫ T   – P dV
 ∂ T V
RT
RT
(A.27)
∞
The Ideal Gas Enthalpy basis
(HID) used by HYSYS is equal
to the ideal gas Enthalpy of
Formation at 25°C and 1 atm.
ID
S – S°
P
------------------- = ln Z – ln ------ +
RT
P°
V
∫
∞
1 ∂P
1
---   – --- dV
R  ∂ T V V
(A.28)
A.4.1 Equations of State
For the Peng-Robinson Equation of State, the enthalpy and entropy
departure calculations use the following relations:
The Ideal Gas Enthalpy basis
(HID) used by HYSYS
changes with temperature
according to the coefficients
on the TDep tab for each
individual component.
0.5
ID
da  V + ( 2 + 1 )b
1
H–H
-----------------------------------
–
ln
-------------------- = Z – 1 – ------------------a
T

1.5
dt
RT
 V + ( 2 0.5 – 1 )b
2 bRT
(A.29)
ID
0.5
S – S°
A
T da  V + ( 2 + 1 )b
P – ------------------------------------------------------
------------------- = ln ( Z – B ) – ln ----ln

R
P° 2 1.5 bRT a d t
 V + ( 2 0.5 – 1 )b
(A.30)
A-45
A-46
Enthalpy & Entropy Departure
where:
N
a =
N
∑ ∑ xi xj ( ai aj )
0.5
( 1 – k ij )
(A.31)
i = 1 j= 1
For the SRK Equation of State:
ID
1
da
b
H–H
-------------------- = Z – 1 – ---------- a – T ------ ln  1 + ---

bRT
dt
V
RT
(A.32)
ID
S – S°
T da
B
P +A
------------------- = ln ( Z – b ) – ln ----- --- --- ------ ln  1 + ---
Z
RT
P° B a dt
(A.33)
A and B term definitions are provided below:
Peng-Robinson
Soave-Redlich-Kwong
bi
RT ci
0.077796 ----------P ci
RT ci
0.08664 ----------P ci
ai
a ci α i
a ci α i
aci
( RT ci )
0.457235 -----------------P ci
( RT ci )
0.42748 -----------------P ci
2
1 + m i ( 1 – T ri )
1 + m i ( 1 – T ri )
0.5
0.5
αi
mi
2
2
0.37646 + 1.54226ω i – 0.26992ω i
where:
N
a =
N
∑ ∑ xi xj ( ai aj )
0.5
i =1 j=1
R = Ideal Gas constant
H = Enthalpy
S = Entropy
A-46
( 1 – k ij )
2
0.48 + 1.574ω i – 0.176ω i
Property Methods & Calculations
A-47
subscripts:
ID = Ideal Gas
o = reference state
PRSV
The PRSV equation of state is an extension of the Peng-Robinson
equation using an extension of the κ expression as shown below:
0.5
αi = [ 1 + κi ( 1 – Tr ) ]
2
(A.34)
0.5
κ i = κ 0i ( 1 + T ri ) ( 0.7 – T ri )
2
3
κ 0i = 0.378893 + 1.4897153ω i – 0.17131848ω i + 0.0196554ω i
This results in the replacement of the αi term in the definitions of the A
and B terms shown previously by the αi term shown above.
A.4.2 Activity Models
The Liquid enthalpy and entropy for Activity Models is based on the
Cavett Correlation as shown below:
for Tri < 1:
L
ID
 ∆H i ° L ( sb ) ∆H i ° L ( sb )
H –H
----------------------- = max  --------------------------, --------------------------
Tc
Tc
Tc


i
i
i
(A.35)
L
ID
 ∆H i ° L ( sb ) ∆H i ° L ( sp )
H –H
----------------------- = max  --------------------------, --------------------------
Tc
Tc
Tc


i
i
i
(A.36)
for Tri ≥ 1:
A-47
A-48
Enthalpy & Entropy Departure
where:
1 – a3 ( T r – 0.1 )
∆H i ° L ( sb )
i
-------------------------- = a 1 + a 2 ( 1 – T r )
i
Tc
(A.37)
∆H i ° L ( sp )
2
3
4
2
-------------------------- = max ( 0, b 1 + b 2 T r + b 3 T r + b 4 T r + b 5 T r )
i
i
i
i
Tc
(A.38)
i
i
where a1, a2, and a3 are functions of the Cavett parameter, fitted to
match one known heat of vapourization.
The Gas enthalpies and entropies are dependent on the model chosen
to represent the vapour phase behaviour:
Ideal Gas:
H = H
T2
S =
ID
S°
=
ID
C v dT
(A.39)
V2
- + R ln -----∫ -----------T
V1
(A.40)
T1
Redlich-Kwong:
ID
1.5
H–H
b
-------------------- = Z – 1 – ---------- ln  1 + ---
bRT 
RT
V
(A.41)
ID
S – S°
A 
B
P + ------ ln 1 + ---
------------------- = ln ( Z – b ) – ln ----Z
RT
P° 2B 
(A.42)
Virial Equation:
ID
T dB
H–H
-------------------- = – ------------- ------- + ( Z – 1 )
V – B dt
RT
A-48
(A.43)
Property Methods & Calculations
A-49
ID
S – S°
RT dB
V
V
------------------- = – ------------- ------- – R ln ------------- + R ln -----V – B dT
R
V–B
V°
where:
(A.44)
B = second virial coefficient of the mixture
A.4.3 Lee-Kesler Option
The SRK and PR are given in
Section A.3.1 - Equations of
State.
The Lee and Kesler method is an effort to extend the method originally
proposed by Pitzer to temperatures lower than 0.8 Tr. Lee and Kesler
expanded Pitzer’s method expressing the compressibility factor as:
ω
Z = Z ° + ------r ( Z r – Z ° )
ω
where:
(A.45)
Z o = the compressibility factor of a simple fluid
Z r = the compressibility factor of a reference fluid
They chose the reduced form of the BWR equation of state to represent
both Z o and Z r:
D 
B C D
γ
Z = 1 + ----- + ------2 + ------5 + ------------3 β – ------2 e
3
Vr Vr Vr Tr Vr 
Vr 
γ
–  ------2
V r 
(A.46)
where:
VP c
V r = --------RT c
b2 b3 b4
B = b 1 – ----- – -----2 – -----4
Tr T T
r
r
c2 c3
C = c 1 – ----- + -----3
Tr Tr
d2
D = d 1 + ----Tr
A-49
A-50
Enthalpy & Entropy Departure
The constants in these equations were determined using experimental
compressibility and enthalpy data. Two sets of constants, one for the
simple fluid (ωo = 0) and one for the reference fluid (ωr=0.3978, n-C8)
were determined.
The Enthalpy and Entropy departures are computed as follows:
b3
c3
b4


b 2 + 2 ----- + 3 -----2 c 2 – 3 -----2


d


Tr
Tr
Tr
H–H
2
-------------------- = T r  Z – 1 – ------------------------------------- – ------------------- – --------------5- + 3E 
2
RT c


Tr Vr
2T r V r
5T r V r




(A.47)
b4
b3
c3
b 1 + -----2 + 2 -----3 c 1 – 3 -----2
ID
S – S°
Tr
Tr
Tr d1
P
------------------- = ln Z – ln  ------ – --------------------------------– ------------------- – ---------2 + 2E
2


P°
R
V
5V
2V
(A.48)
γ

–  ----- 
c4 

γ   Vr  
- β + 1 –  β + 1 + ------ e
E = ----------
3 
2


2T r γ 
Vr 


(A.49)
ID
r
r
r
For mixtures, the Critical Properties are defined as follows:
N
∑ xi ωi
ω =
i=1
z c = 0.2905 – 0.0851ω i
i
Z c RT c
i
i
V c = ----------------i
Pc
i
1
V c = --8
N
N
∑∑
i=1 j=1
1
T c = --------8V c
N
N
∑∑
i=1 j=1
1 3
1
--- 
 --33
x i x j V c + V c 
j
 i

1
1 3
--- 
 --30.5
3
x i x j V c + V c  ( T c T c )
i
j
i
j


RT c
P c = ( 0.2905 – 0.085ω ) --------Vc
A-50
Property Methods & Calculations
A-51
Fugacity Coefficient
The fugacity coefficient calculations for SRK and Peng Robinson models
is shown below.
Soave-Redlich-Kwong

 b
N
bi
a 1
0.5
0.5
Pb
b
i
ln φ i = – ln  Z – ------- + ( Z – 1 ) ---- – ---------- ---  2a i ∑ x j a j ( 1 – k ij ) – ---- ln  1 + ---

 b

b bRT a 
RT
V


j=1
(A.50)
Peng Robinson
N

 b
0.5
bi
V + ( 2 + 1 )b
a
1  0.5
0.5
Pb
i

---------------------ln φ i = – ln Z – ------- + ( Z – 1 ) – 1.5
2a i ∑ x j a j ( 1 – k ij ) – ---- ln ----------------------------------0.5

 b
b 2 bRT a 
RT
–
(
–
1
)b
V
2


j=1
(A.51)
A.5 Physical & Transport Properties
The physical and transport properties that HYSYS calculates for a given
phase are viscosity, density, thermal conductivity and surface tension.
The models used for the transport property calculations are all preselected to yield the best fit for the system under consideration. For
example, the corresponding states model proposed by Ely and Hanley is
used for viscosity predictions of light hydrocarbons (NBP<155), the Twu
methodology for heavier hydrocarbons, and a modification of the
Letsou-Stiel method for predicting the liquid viscosities of non-ideal
chemical systems.
A complete description of the models used for the prediction of the
transport properties can be found in the references listed in each subsection. All these models are modified by Hyprotech to improve the
accuracy of the correlations.
A-51
A-52
Physical & Transport Properties
In the case of multiphase streams, the transport properties for the mixed
phase are meaningless and are reported as <empty>, although the single
phase properties are known. There is an exception with the pipe and
heat exchanger operations. For three-phase fluids, HYSYS uses
empirical mixing rules to determine the apparent properties for the
combined liquid phases.
A.5.1 Liquid Density
Saturated liquid volumes are obtained using a corresponding states
equation developed by R. W. Hankinson and G. H. Thompson13 which
explicitly relates the liquid volume of a pure component to its reduced
temperature and a second parameter termed the characteristic volume.
This method is adopted as an API standard. The pure compound
parameters needed in the corresponding states liquid density
(COSTALD) calculations are taken from the original tables published by
Hankinson and Thompson, and the API Data Book for components
contained in HYSYS’ library.
The parameters for hypothetical components are based on the API
gravity and the generalized Lu equation. Although the COSTALD
method was developed for saturated liquid densities, it can be applied
to sub-cooled liquid densities, i.e., at pressures greater than the vapour
pressure, using the Chueh and Prausnitz correction factor for
compressed fluids. It is used to predict the density for all systems whose
pseudo-reduced temperature is below 1.0. Above this temperature, the
equation of state compressibility factor is used to calculate the liquid
density.
Hypocomponents generated in the Oil Characterization Environment
have their densities either calculated from internal correlations or
generated from input curves. Given a bulk density, the densities of the
hypocomponent are adjusted such that:
1.0
ρ bulk = -------------xi
∑ -----ρi °
A-52
(A.52)
Property Methods & Calculations
A-53
The characteristic volume for each hypocomponent is calculated using
the adjusted densities and the physical properties. The calculated
characteristic volumes are then adjusted such that the bulk density
calculated from the COSTALD equation matches the density calculated
using the above equation. This ensures that a given volume of fluid
contains the same mass whether it is calculated with the sum of the
component densities or the COSTALD equation.
A.5.2 Vapour Density
The density for all vapour systems at a given temperature and pressure
is calculated using the compressibility factor given by the equation of
state or by the appropriate vapour phase model for Activity Models.
A.5.3 Viscosity
HYSYS automatically selects the model best suited for predicting the
phase viscosities of the system under study. The model selected is from
one of the three available in HYSYS: a modification of the NBS method
(Ely and Hanley), Twu’s model, or a modification of the Letsou-Stiel
correlation. HYSYS selects the appropriate model using the following
criteria:
Chemical System
Vapour Phase
Liquid Phase
Lt Hydrocarbons (NBP<155°F)
Mod Ely & Hanley
Mod Ely & Hanley
Hvy Hydrocarbons (NBP>155°F)
Mod Ely & Hanley
Twu
Non-Ideal Chemicals
Mod Ely & Hanley
Mod Letsou-Stiel
All of the models are based on corresponding states principles and are
modified for more reliable application. Internal validation showed that
these models yielded the most reliable results for the chemical systems
shown. Viscosity predictions for light hydrocarbon liquid phases and
vapour phases were found to be handled more reliably by an in-house
modification of the original Ely and Hanley model, heavier hydrocarbon
liquids were more effectively handled by Twu’s model, and chemical
systems were more accurately handled by an in-house modification of
the original Letsou-Stiel model.
A-53
A-54
Physical & Transport Properties
A complete description of the original corresponding states (NBS)
model used for viscosity predictions is presented by Ely and Hanley in
their NBS publication. The original model is modified to eliminate the
iterative procedure for calculating the system shape factors. The
generalized Leech-Leland shape factor models are replaced by
component specific models. HYSYS constructs a PVT map for each
component using the COSTALD for the liquid region. The shape factors
are adjusted such that the PVT map can be reproduced using the
reference fluid.
The shape factors for all the library components are already regressed
and included in the Pure Component Library. Hypocomponent shape
factors are regressed using estimated viscosities. These viscosity
estimations are functions of the hypocomponent Base Properties and
Critical Properties.
Hypocomponents generated in the Oil Characterization Environment
have the additional ability of having their shape factors regressed to
match kinematic or dynamic viscosity assays.
The general model employs CH4 as a reference fluid and is applicable to
the entire range of non-polar fluid mixtures in the hydrocarbon
industry. Accuracy for highly aromatic or naphthenic crudes is
increased by supplying viscosity curves when available, since the pure
component property generators were developed for average crude oils.
The model also handles H2O and acid gases as well as quantum gases.
Although the modified NBS model handles these systems very well, the
Twu method was found to do a better job of predicting the viscosities of
heavier hydrocarbon liquids. The Twu model9 is also based on
corresponding states principles, but has implemented a viscosity
correlation for n-alkanes as its reference fluid instead of CH4. A
complete description of this model is given in the paper entitled
“Internally Consistent Correlation for Predicting Liquid Viscosities of
Petroleum Fractions”15.
For chemical systems the modified NBS model of Ely and Hanley is used
for predicting vapour phase viscosities, whereas a modified form of the
Letsou-Stiel model is used for predicting the liquid viscosities. This
method is also based on corresponding states principles and was found
to perform satisfactorily for the components tested.
A-54
Property Methods & Calculations
A-55
The shape factors contained in the HYSYS Pure Component Library are
fit to match experimental viscosity data over a broad operating range.
Although this yields good viscosity predictions as an average over the
entire range, improved accuracy over a narrow operating range can be
achieved by using the Tabular features (see Chapter 2 - Fluid Package
for more information).
A.5.4 Liquid Phase Mixing Rules for Viscosity
The estimates of the apparent liquid phase viscosity of immiscible
Hydrocarbon Liquid - Aqueous mixtures are calculated using the
following "mixing rules":
•
If the volume fraction of the hydrocarbon phase is greater than or
equal to 0.5, the following equation is used17:
µ eff = µ oil e
where:
3.6 ( 1 – ν oil )
(A.53)
µ eff = apparent viscosity
µ oil = viscosity of Hydrocarbon phase
ν oil = volume fraction Hydrocarbon phase
•
If the volume fraction of the hydrocarbon phase is less than 0.33, the
following equation is used18:
 µ oil + 0.4µ H2 O
- µ H O
µ eff = 1 + 2.5ν oil  ----------------------------------2
 µ oil + µ H2 O 
where:
(A.54)
µ eff = apparent viscosity
µ oil = viscosity of Hydrocarbon phase
µH
2O
= viscosity of Aqueous phase
ν oil = volume fraction Hydrocarbon phase
•
If the volume of the hydrocarbon phase is between 0.33 and 0.5,
the effective viscosity for combined liquid phase is calculated
using a weighted average between Equation (A.53) and
Equation (A.54).
A-55
A-56
Physical & Transport Properties
The remaining properties of the pseudo phase are calculated as follows:
MW eff =
ρ eff
∑ xi MWi
1
= ----------------xi 
∑  ---ρ
(molecular weight)
(mixture density)
(A.55)
i
Cp
eff
=
∑ xi Cp
(mixture specific heat)
i
A.5.5 Thermal Conductivity
As in viscosity predictions, a number of different models and
component specific correlations are implemented for prediction of
liquid and vapour phase thermal conductivities. The text by Reid,
Prausnitz and Poling16 was used as a general guideline in determining
which model was best suited for each class of components.
For hydrocarbon systems the corresponding states method proposed by
Ely and Hanley14 is generally used. The method requires molecular
weight, acentric factor and ideal heat capacity for each component.
These parameters are tabulated for all library components and may
either be input or calculated for hypothetical components. It is
recommended that all of these parameters be supplied for nonhydrocarbon hypotheticals to ensure reliable thermal conductivity
coefficients and enthalpy departures.
The modifications to the method are identical to those for the viscosity
calculations. Shape factors calculated in the viscosity routines are used
directly in the thermal conductivity equations. The accuracy of the
method depends on the consistency of the original PVT map.
The Sato-Reidel method16 is used for liquid phase thermal conductivity
predictions of glycols and acids, the Latini et al. method16 is used for
esters, alcohols and light hydrocarbons in the range of C3 - C7, and the
Missenard and Reidel method16 is used for the remaining components.
A-56
Property Methods & Calculations
A-57
For vapour phase thermal conductivity predictions, the Misic and
Thodos, and Chung et al.16 methods are used (except for H2O, C1, H2,
CO2, NH3 which use a polynomial for pure components). The effect of
higher pressure on thermal conductivities is taken into account by the
Chung et al. method.
For liquid phase thermal conductivity predictions:
•
•
•
•
•
•
For pure water, use the Steam Tables.
When water and DEG exist at the same time, some special
treatment for those two compounds.
For water, DEG, C1,C2,C3, 3M-3Epentane, propene, TEG, EG,
He, H2, Ethylene, Ammonia, a polynomial is used.
For Hydrocarbon with MW > 140 and TR < 0.8, a modified
Missenard & Reidel method is used. Because the Missenard and
Reidel method needs Cp at standard condition, HYSYS does not
use the unmodified version.
For Alcohol, Ester and Hydrocarbons not mentioned in the last
category, Latini is used.
For others, Sato-Reidel is used.
As with viscosity, the thermal conductivity for two liquid phases is
approximated by using empirical mixing rules for generating a single
pseudo liquid phase property. The thermal conductivity for an
immiscible binary of liquid phases is calculated by the following
equation21:
λL =
i
∑ ∑ φi φj kij
i
where:
(A.56)
j
κ ij = liquid thermal conductivity of pure component i or j at
temperature T
2
k ij = -------------------------------------( 1 ⁄ ki ) + ( 1 ⁄ kj )
φi =
xi Vi
---------------------∑ xk Vk
k=1
xi = mole fraction of liquid i
Vi - molar volume of liquid i
xk = mole fraction of component k
Vk = molar volume of component k
A-57
A-58
Physical & Transport Properties
For a binary system the equation simplifies to:
λL
2
mix
2
= φ L λ L + 2φ L φ L λ 12 + φ L λ L
1
1
1
2
2
(A.57)
2
A.5.6 Surface Tension
Surface tensions for hydrocarbon systems are calculated using a
modified form of the Brock and Bird equation8. The equation expresses
the surface tension, σ, as a function of the reduced and critical
properties of the component. The basic form of the equation was used
to regress parameters for each family of components.
2⁄3 1⁄3
Tc Q ( 1
σ = Pc
where:
a
– TR ) × b
(A.58)
σ = surface tension (dynes/cm2)
Q = 0.1207[1.0 + TBR ln Pc /(1.0 - TBR)] - 0.281
TBR = reduced boiling point temperature (Tb/Tc)
a = parameter fitted for each chemical class
b = c o + c 1 ω + c 2 ω 2 + c 3 ω 3 (parameter fitted for each chemical class,
expanded as a polynomial in acentricity)
For aqueous systems, HYSYS employs a polynomial to predict the
surface tension. It is important to note that HYSYS predicts only liquidvapour surface tensions.
A-58
Property Methods & Calculations
A-59
A.5.7 Heat Capacity
Heat Capacity is calculated using a rigorous Cv value whenever HYSYS
can. The method used is given by the following equations:
2
C p – C v = – T ⋅ ( dV ⁄ dT ) ⁄ ( dV ⁄ dT )
(A.59)
However, when ever this equation fails to provide an answer, HYSYS
falls back to the semi-ideal Cp/Cv method by computing Cp/Cv as Cp/
(Cp-R), which is only approximate and valid for ideal gases. Examples of
when HYSYS uses the ideal method are:
•
•
•
•
Equation (A.59) fails to return an answer
The stream has a solid phase
abs(dV/dP) < 1e-12
Cp/Cv < 0.1or Cp/Cv > 20 - this is outside the range of applicability
of the equation used so HYSYS falls back to the ideal method
A.6 Volumetric Flow Rate
Calculations
HYSYS has the ability to interpret and produce a wide assortment of
flow rate data. It can accept several types of flow rate information for
stream specifications as well as report back many different flow rates for
streams, their phases and their components. One drawback of the large
variety available is that it often leads to some confusion as to what
exactly is being specified or reported, especially when volumetric flow
rates are involved.
In the following sections, the available flow rates are listed, each
corresponding density basis is explained, and the actual formulation of
the flow rate calculations is presented. For volumetric flow rate data that
is not directly accepted as a stream specification, a final section is
provided that outlines techniques to convert your input to mass flow
rates.
A-59
A-60
Volumetric Flow Rate Calculations
A.6.1 Available Flow Rates
Many types of flow rates appear in HYSYS output. However, only a
subset of these are available for stream specifications.
Flow Rates Reported in the Output
The flow rate types available through the numerous reporting methods property views, workbook, PFD, specsheets etc. are:
•
•
•
•
•
•
•
Molar Flow
Mass Flow
Std Ideal Liq Vol Flow
Liq Vol Flow @Std Cond
Actual Volume Flow
Std Gas Flow
Actual Gas Flow
Flow Rates Available for Specification
The following flow rate types are available for stream specifications:
•
•
•
Molar Flows
Mass Flows
LiqVol Flows
A.6.2 Liquid & Vapour Density Basis
The volumetric flow rate
reference state is defined as
60°F and 1 atm when using
Field units or 15°C and 1 atm
when using SI units.
Actual Densities are
calculated at the stream
Temperature and Pressure.
A-60
All calculations for volumetric stream flows are based on density. HYSYS
uses the following density basis:
Density Basis
Description
Std Ideal Liq Mass
Density
This is calculated based on ideal mixing of pure component
ideal densities at 60°F.
Liq Mass Density
@Std Cond
This is calculated rigorously at the standard reference state for
volumetric flow rates.
Actual Liquid
Density
This is calculated rigorously at the flowing conditions of the
stream (i.e., at stream T and P).
Property Methods & Calculations
A-61
Density Basis
Description
Standard Vapour
Density
This is determined directly from the Ideal Gas law.
Actual Vapour
Density
This is calculated rigorously at the flowing conditions of the
stream (i.e., at stream T and P).
Calculation of Standard & Actual Liquid Densities
The Standard and Actual liquid densities are calculated rigorously at the
appropriate T and P using the internal methods of the chosen property
package. Flow rates based upon these densities automatically take into
account any mixing effects exhibited by non-ideal systems. Thus, these
volumetric flow rates may be considered as "real world".
Calculation of Standard Ideal Liquid Mass Density
Contrary to the rigorous densities, the Standard Ideal Liquid Mass
density of a stream does not take into account any mixing effects due to
its simplistic assumptions. Thus, flow rates that are based upon it do not
account for mixing effects and are more empirical in nature. The
calculation is as follows:
1
Ideal Density Stream = ---------------------xi
∑ ------------Ideal
ρi
where:
(A.60)
xi = molar fraction of component i
ρi
Ideal
= pure component Ideal Liquid density
HYSYS contains Ideal Liquid densities for all components in the Pure
Component Library. These values are determined in one of three ways,
based on the characteristics of the component, as described below:
Case 1 - For any component that is a liquid at 60°F and 1 atm, the data
base contains the density of the component at 60°F and 1 atm.
Case 2 - For any component that can be liquified at 60°F and pressures
greater than 1 atm, the data base contains the density of the component
at 60°F and Saturation Pressure.
A-61
A-62
Volumetric Flow Rate Calculations
Case 3 - For any component that is non-condensable at 60°F under any
pressure, i.e., 60°F is greater than the critical temperature of the
component, the data base contains GPA tabular values of the equivalent
liquid density. These densities were experimentally determined by
measuring the displacement of hydrocarbon liquids by dissolved noncondensable components.
For all hypothetical components, the Standard Liquid density (Liquid
Mass Density @Std Conditions) in the Base Properties is used in the
Ideal Liquid density (Std Ideal Liq Mass Density) calculation. If a density
is not supplied, the HYSYS estimated liquid mass density (at standard
conditions) is used. Special treatment is given by the Oil
Characterization feature to its hypocomponent such that the ideal
density calculated for its streams match the assay, bulk property, and
flow rate data supplied in the Oil Characterization Environment.
A.6.3 Formulation of Flow Rate Calculations
The various procedures used to calculate each of the available flow rates
are detailed below, based on a known molar flow.
Molar Flow Rate
Total Molar Flow = Molar Flow Stream
(A.61)
Mass Flow = Total Molar Flow × MW Stream
(A.62)
Mass Flow
A-62
Property Methods & Calculations
A-63
Std Ideal Liq Vol Flow
Even if a stream is all vapour,
it still has a Liq Volume flow,
based upon the stream’s
Standard Ideal Liquid Mass
density, whose calculation is
detailed in the previous
section.
This volumetric flow rate is calculated using the ideal density of the
stream and thus is somewhat empirical in nature.
Total Molar Flow × MW Stream
LiqVolFlow = -------------------------------------------------------------------------Ideal Density Stream
(A.63)
Liq Vol Flow @Std Cond
This volumetric flow rate is calculated using a rigorous density
calculated at standard conditions, and reflects non-ideal mixing effects.
Molar Flow × MW
Std Liquid Volume Flow = --------------------------------------------Std Liq Density
(A.64)
Actual Volume Flow
This volumetric flow rate is calculated using a rigorous liquid density
calculation at the actual stream T and P conditions, and reflects nonideal mixing effects.
Molar Flow × MW
Actual Volume Flow = --------------------------------------------Density
(A.65)
Standard Gas Flow
Standard gas flow is based on the molar volume of an ideal gas at
standard conditions. It is a direct conversion from the stream’s molar
flow rate, based on the following:
•
•
Ideal Gas at 60°F and 1 atm occupies 379.46 ft3/lbmole
Ideal Gas at 15°C and 1 atm occupies 23.644 m3/kgmole
A-63
A-64
Volumetric Flow Rate Calculations
Actual Gas Flow
This volumetric flow rate is calculated using a rigorous vapour density
calculation at the actual stream T and P conditions, and reflects nonideal mixing and compressibility effects.
Molar Flow × MW
Actual Gas Flow = --------------------------------------------Density
(A.66)
A.6.4 Volumetric Flow Rates as Specifications
If you require that the flow rate of your stream be specified based on
actual density or standard density as opposed to Standard Ideal Mass
Liquid density, you must use one of the following procedures:
Liq Vol Flow @Std Cond
1.
Specify the composition of your stream.
2.
Use the standard ideal liquid mass density reported for the stream
and calculate the corresponding mass flow rate either manually, or
in the SpreadSheet.
3.
Use this calculated mass flow as the specification for the stream.
Actual Liquid Volume Flow
A-64
1.
Specify the composition and the flowing conditions (T and P) of
your stream.
2.
Use the density reported for the stream and calculate the
corresponding mass flow rate either manually, or in our
spreadsheet.
3.
Use this calculated mass flow as the specification for the stream.
Property Methods & Calculations
A-65
A.7 Flash Calculations
Specified variables can only
be re-specified by you or
through Recycle Adjust, or
SpreadSheet operations. They
do not change through any
heat or material balance
calculations.
Rigorous three phase calculations are performed for all equations of
state and activity models with the exception of Wilson’s equation, which
only performs two phase vapour-liquid calculations. As with the Wilson
Equation, the Amines and Steam property packages only support two
phase equilibrium calculations.
HYSYS uses internal intelligence to determine when it can perform a
flash calculation on a stream, and then what type of flash calculation
needs to be performed on the stream. This is based completely on the
degrees of freedom concept. Once the composition of a stream and two
property variables are known, (vapour fraction, temperature, pressure,
enthalpy or entropy) one of which must be either temperature or
pressure, the thermodynamic state of the stream is defined. When
HYSYS recognizes that a stream is thermodynamically defined, it
performs the correct flash automatically in the background. You never
have to instruct HYSYS to perform a flash calculation.
Property variables can either be specified by you or back-calculated
from another unit operation. A specified variable is treated as an
independent variable. All other stream properties are treated as
dependent variables and are calculated by HYSYS.
If a flash calculation is
performed on a stream,
HYSYS knows all the property
values of that stream, i.e.,
thermodynamic, physical and
transport properties.
In this manner, HYSYS also recognizes when a stream is overspecified.
For example, if you specify three stream properties plus composition,
HYSYS prints out a warning message that an inconsistency exists for
that stream. This also applies to streams where an inconsistency is
created through HYSYS calculations.
For example, if a stream Temperature and Pressure are specified in a
flowsheet, but HYSYS back-calculates a different temperature for that
stream as a result of an enthalpy balance across a unit operation, HYSYS
generates an Inconsistency message.
HYSYS automatically performs the appropriate flash calculation when it
recognizes that sufficient stream information is known. This information
is either specified by the user or calculated by an operation.
Depending on the known stream information, HYSYS performs one of
the following flashes: T-P, T-VF, T-H, T-S, P-VF, P-H, or P-S.
A-65
A-66
Flash Calculations
A.7.1 T-P Flash Calculation
The independent variables for this type of flash calculation are the
temperature and pressure of the system, while the dependent variables
are the vapour fraction, enthalpy, and entropy.
See Section 2.4.4 - Stability
Test Tab for options on how to
instruct HYSYS to perform
phase stability tests.
With the equations of state and activity models, rigorous calculations
are performed to determine the co-existence of immiscible liquid
phases and the resulting component distributions by minimization of
the Gibbs free energy term. For vapour pressure models or the semiempirical methods, the component distribution is based on the
Kerosene solubility data (Figure 9A1.4 of the API Data Book).
If the mixture is single-phase at the specified conditions, the property
package calculates the isothermal compressibility (dv/dp) to determine
if the fluid behaves as a liquid or vapour. Fluids in the dense-phase
region are assigned the properties of the phase that best represents their
current state.
Use caution in specifying
solids with systems that are
otherwise all vapour. Small
amounts of non-solids may
appear in the "liquid" phase.
Note that material solids appear in the liquid phase of two-phase
mixtures, and in the heavy (aqueous/slurry) phase of three-phase
systems. Therefore, when a separator is solved using a T-P flash, the
vapour phase is identical regardless of whether or not solids are present
in the feed to the flash drum.
A.7.2 Vapour Fraction Flash
Vapour fraction and either temperature or pressure are the independent
variables for this type of calculation. This class of calculation embodies
all fixed quality points including bubble points (vapour pressure) and
dew points.
To perform bubble point calculation on a stream of known
composition, simply specify the Vapour Fraction of the stream as 0.0
and define the temperature or pressure at which the calculation is
desired. For a dew point calculation, simply specify the Vapour Fraction
of the stream as 1.0 and define the temperature or pressure at which the
dew point calculation is desired. Like the other types of flash
calculations, no initial estimates are required.
A-66
Property Methods & Calculations
All of the solids appear in the
liquid phase.
A-67
The vapour fraction is always shown in terms of the total number of
moles. For example, the vapour fraction (VF) represents the fraction of
vapour in the stream, while the fraction, (1.0 - VF), represents all other
phases in the stream (i.e., a single liquid, 2 liquids, a liquid and a solid).
Dew Points
Given a vapour fraction specification of 1.0 and either temperature or
pressure, the property package calculates the other dependent variable
(P or T). If temperature is the second independent variable, HYSYS
calculates the dew point pressure. Likewise, if pressure is the
independent variable, then the dew point temperature is calculated.
Retrograde dew points may be calculated by specifying a vapour
fraction of -1.0. It is important to note that a dew point that is retrograde
with respect to temperature can be normal with respect to pressure and
vice versa.
Bubble Points/Vapour Pressure
Vapour pressure and bubble
point pressure are
synonymous.
A vapour fraction specification of 0.0 defines a bubble point calculation.
Given this specification and either temperature or pressure, the
property package calculates the unknown T or P variable. As with the
dew point calculation, if the temperature is known, HYSYS calculates
the bubble point pressure and conversely, given the pressure, HYSYS
calculates the bubble point temperature. For example, by fixing the
temperature at 100°F, the resulting bubble point pressure is the true
vapour pressure at 100°F.
Quality Points
HYSYS calculates the
retrograde condition for the
specified vapour quality if the
vapour fraction is input as a
negative number.
Bubble and dew points are special cases of quality point calculations.
Temperatures or pressures can be calculated for any vapour quality
between 0.0 and 1.0 by specifying the desired vapour fraction and the
corresponding independent variable. If HYSYS displays an error when
calculating vapour fraction, then this means that the specified vapour
fraction doesn't exist under the given conditions, i.e., the specified
pressure is above the cricondenbar, or the given temperature lies to the
right of the cricondentherm on a standard P-T envelope.
A-67
A-68
Flash Calculations
A.7.3 Enthalpy Flash
If a specified amount of energy
is to be added to a stream, this
may be accomplished by
specifying the energy stream
into either a Cooler/Heater or
Balance operation.
Given the enthalpy and either the temperature or pressure of a stream,
the property package calculates the unknown dependent variables.
Although the enthalpy of a stream cannot be specified directly, it often
occurs as the second property variable as a result of energy balances
around unit operations such as valves, heat exchangers and mixers.
If HYSYS responds with an error message, and cannot find the specified
property (temperature or pressure), this probably means that an
internally set temperature or pressure bound was encountered. Since
these bounds are set at quite large values, there is generally some
erroneous input that is directly or indirectly causing the problem, such
as an impossible heat exchange.
A.7.4 Entropy Flash
Given the entropy and either the temperature or pressure of a stream,
the property package calculates the unknown dependent variables.
A.7.5 Electrolyte Flash
Refer to the HYSYS OLI
Interface Reference Guide
for detailed information on
electrolyte flash and
aqueous thermodynamics.
The electrolyte stream flash differs from the HYSYS material stream
flash to handle the complexities of speciation for aqueous electrolyte
systems. The HYSYS OLI Interface package is an interface to the OLI
Engine (OLI Systems) that enables simulations within HYSYS using the
full functionality and capabilities of the OLI Engine for flowsheet
simulation.
When the OLI_Electrolyte property package is associated with material
streams, the streams exclusively become electrolyte material streams in
the flowsheet. That is, the stream conducts a simultaneous phase and
reaction equilibrium flash. For the model used and the reactions
involved in the flash calculation, refer to the HYSYS OLI Interface
reference guide.
A-68
Property Methods & Calculations
A-69
An electrolyte material stream in HYSYS can perform the following type
of flashes:
•
•
•
•
•
TP Flash
PH Flash
TH Flash
PV Flash
TV Flash
Due to the involvement of reactions in the stream flash, the equilibrium
stream flash may result in a different molar flow and composition from
the specified value. Therefore, mass and energy are conserved for an
electrolyte material stream against the HYSYS stream for mass, molar
and energy balances.
Limitations exist in the HYSYS OLI Interface package in the calculation
of the stream flash results. The calculation for the electrolyte flash
results must fall within the following physical ranges to be valid.
•
•
•
•
composition of H2O in aqueous phase must be > 0.65.
Temperature must be between 0 and 300°C.
Pressure must be between 0 and 1500 atm.
Ionic strength must be between 0 and 30 mole/kg-H2O.
Refer to Section 1.7 - Range of Applicability of the HYSYS OLI Interface
Reference Guide for more information on the limitations of the HEO
models.
A.7.6 Handling of Water
Water is handled differently depending on the correlation being used.
The PR and PRSV equations are enhanced to handle H2O rigorously
whereas the semi-empirical and vapour pressure models treat H2O as a
separate phase using steam table correlations.
In these correlations, H2O is assumed to form an ideal, partiallymiscible mixture with the hydrocarbons and its K value is computed
from the relationship:
p°
K ω = ------------( xs P )
(A.67)
A-69
A-70
Flash Calculations
where:
p° = vapour pressure of H2O from Steam Tables
P = system pressure
xs = solubility of H2O in hydrocarbon liquid at saturation conditions.
The value for xs is estimated by using the solubility data for kerosene as
shown in Figure 9A1.4 of the API Data Book19. This approach is generally
adequate when working with heavy hydrocarbon systems. However, it is
not recommended for gas systems.
For three phase systems, only the PR and PRSV property package and
Activity Models allow components other than H2O in the second liquid
phase. Special considerations are given when dealing with the
solubilities of glycols and CH3OH. For acid gas systems, a temperature
dependent interaction parameter was used to match the solubility of the
acid component in the water phase.
The PR equation considers the solubility of hydrocarbons in H2O, but
this value may be somewhat low. The reason for this is that a
significantly different interaction parameter must be supplied for cubic
equations of state to match the composition of hydrocarbons in the
water phase as opposed to the H2O composition in the hydrocarbon
phase. For the PR equation of state, the latter case was assumed more
critical. The second binary interaction parameter in the PRSV equation
allows for an improved solubility prediction in the alternate phase.
With the activity coefficient models, the limited mutual solubility of H2O
and hydrocarbons in each phase can be taken into account by
implementing the insolubility option (please refer to Section A.3.2 Activity Models). HYSYS generates, upon request, interaction
parameters for each activity model (with the exception of the Wilson
equation) that are fitted to match the solubility of H2O in the liquid
hydrocarbon phase and hydrocarbons in the aqueous phase based on
the solubility data referred to in that section.
The Peng-Robinson and SRK property packages will always force the
water rich phase into the heavy liquid phase of a three phase stream. As
such, the aqueous phase is always forced out of the bottom of a three
phase separator, even if a light liquid phase (hydrocarbon rich) does not
exist. Solids are always carried in the second liquid phase.
A-70
Property Methods & Calculations
A-71
A.7.7 Supercritical Handling
HYSYS reports a vapor fraction of zero or one, for a stream under
supercritical conditions. Theoretically, this value doesn’t have any
physical meaning for a supercritcial fluid, since there is no distinction of
liquid or vapor phases in a supercritical region. However, it is important
to determine if a supercritical fluid is liquid-like or a vapor-like fluid.
This is because some of the properties reported in HYSYS are calculated
using certain sets of specific phase models. In other words, phase
identification has to be carried out in order to decide which model to
use to calculate these properties.
In HYSYS, all flash results go through a phase order function to identify
the phase type. Different packages have their own different order.
For example, the following criteria are used to identify phase types for
the PR, SRK, SourPR, and Sour SRK cubic equations of state at
supercritical region:
1.
If the compressibility factor (Z) is greater than 0.3, and the
isothermal compressibility factor (beta) is greater than 0.75, a vapor
fraction of 1.0 is assigned to the stream.
2.
If Z is greater than 0.75 and the sum of composition of light
compounds (NBP<230K) is greater than the sum of composition of
heavy compounds, a vapor fraction of 1.0 is assigned to the stream.
Otherwise, vapor fraction of 0 is assigned to the stream and liquid
correlations are used.
A-71
A-72
Flash Calculations
A.7.8 Solids
HYSYS does not check for solid phase formation of pure components
within the flash calculations, however, incipient solid formation
conditions for CO2 and hydrates can be predicted with the Utility
Package (for more information, refer to Chapter 14 - Utilities of the
Operations Guide).
Solid materials such as catalyst or coke can be handled as user-defined,
solid type components. The HYSYS property package takes this type of
component into account in the calculation of the following stream
variables: stream total flow rate and composition (molar, mass and
volume), vapour fraction, entropy, enthalpy, specific heat, density,
molecular weight, compressibility factor, and the various critical
properties. Transport properties are computed on a solids-free basis.
Note that solids are always carried in the second liquid phase, i.e., the
water rich phase.
Solids do not participate in vapour-liquid equilibrium (VLE)
calculations. Their vapour pressure is taken as zero. However, since
solids do have an enthalpy contribution, they have an effect on heat
balance calculations. Thus, while the results of a Temperature flash are
the same whether or not such components are present, an Enthalpy
flash is affected by the presence of solids.
A solid material component is entered as a hypothetical component in
HYSYS. See Chapter 3 - Hypotheticals for more information on
Hypotheticals.
A-72
Property Methods & Calculations
A-73
A.7.9 Stream Information
When a flash calculation occurs for a stream, the information that is
returned depends on the phases present within the stream. The
following table shows the stream properties that are calculated for each
phase:
Steam Property
Applicable PhasesA
F - Feed
Vapour Phase Mole Fraction
F
V
L
S
V - Vapour
Vapour Phase Mass Fraction
F
V
L
S
L - Liquid
Vapour Phase Volume Fraction
F
V
L
S
S - Solid
Temperature
F
V
L
S
Pressure
F
V
L
S
Flow
F
V
L
S
Mass Flow
F
V
L
S
Liquid Volume Flow (Std, Ideal)
F
V
L
S
Volume Flow
F
V
L
S
Std. Gas Flow
F
V
L
S
Std. Volume Flow
F
L
S
Energy
F
V
L
S
Molar Enthalpy
F
V
L
S
Mass Enthalpy
F
V
L
S
Molar Entropy
F
V
L
S
Mass Entropy
F
V
L
S
Molar Volume
F
V
L
S
Molar Density
F
V
L
S
Mass Density
F
V
L
S
Std. Liquid Mass Density
FD
L
S
Molar Heat Capacity
F
V
L
S
Mass Heat Capacity
F
V
L
S
CP/CV
F
V
L
S
Thermal Conductivity
F
B,D
V
L
Viscosity
FB,D
V
L
Kinematic Viscosity
FB,D
V
Surface Tension
FB
Molecular Weight
F
V
L
S
Z Factor
FB
V
L
S
Air SG
FB
V
Watson (UOP) K Value
F
V
L
S
Component Mole Fraction
F
V
L
S
L
L
A-73
A-74
Flash Calculations
Steam Property
Applicable PhasesA
Component Mass Fraction
F
V
L
S
Component Volume Fraction
F
V
L
S
Component Molar Flow
F
V
L
S
Component Mass Flow
F
V
L
S
Component Volume Flow
F
V
L
S
K Value (y/x)
Lower Heating Value
Mass Lower Heating Value
A
Molar Liquid Fraction
F
V
L
S
Molar Light Liquid Fraction
F
V
L
S
Molar Heavy Liquid Fraction
F
S
V
L
Molar Heat of Vapourization
F
C
V
L
Mass Heat of Vapourization
FC
V
L
Partial Pressure of CO2
F
V
L
S
Stream phases:
F - Feed
V - Vapour
L - Liquid
S - Solid
BPhysical
property queries are allowed on the feed phase of single phase streams.
C
Physical property queries are allowed on the feed phase only for streams containing vapour
and/or liquid phases.
D
Physical property queries are allowed on the feed phase of liquid streams with more than one
liquid phase.
A-74
Property Methods & Calculations
A-75
A.8 References
1
Peng, D. Y. and Robinson, D. B., "A Two Constant Equation of State", I.E.C.
Fundamentals, 15, pp. 59-64 (1976).
2
Soave, G., Chem Engr. Sci., 27, No. 6, p. 1197 (1972).
3
Knapp, H., et al., "Vapor-Liquid Equilibria for Mixtures of Low Boiling
Substances", Chemistry Data Series Vol. VI, DECHEMA, 1989.
4
Kabadi, V.N., and Danner, R.P. A Modified Soave-Redlich-Kwong Equation of
State for Water-Hydrocarbon Phase Equilibria, Ind. Eng. Chem. Process
Des. Dev. 1985, Volume 24, No. 3, pp 537-541.
5
Stryjek, R., Vera, J.H., J. Can. Chem. Eng., 64, p. 334, April 1986.
6
API Publication 955, A New Correlation of NH3, CO2 and H2S Volatility Data
From Aqueous Sour Water Systems, March 1978.
7
Zudkevitch, D., Joffee, J. "Correlation and Prediction of Vapor-Liquid
Equilibria with the Redlich-Kwong Equation of State", AIChE Journal,
Volume 16, No. 1, January pp. 112-119.
8
Reid, C.R., Prausnitz, J.M. and Sherwood, T.K., "The Properties of Gases and
Liquids", McGraw-Hill Book Company, 1977.
9
Prausnitz, J.M., Lichtenthaler, R.N., Azevedo, E.G., "Molecular
Thermodynamics of Fluid Phase Equilibria", 2nd. Ed., McGraw-Hill, Inc.
1986.
10
Chao, K. D. and Seader, J. D., A.I.Ch.E. Journal, pp. 598-605, December 1961.
11
Grayson, H. G. and Streed, G. W., "Vapour-Liquid Equilibria for High
Temperature, High Pressure Systems", 6th World Petroleum Congress, West
Germany, June 1963.
12
Jacobsen, R.T and Stewart, R.B., 1973. "Thermodynamic Properties of
Nitrogen Including Liquid and Vapour Phases from 63 K to 2000K with
Pressure to 10 000 Bar." J. Phys. Chem. Reference Data, 2: 757-790.
13 Hankinson,
R.W. and Thompson, G.H., A.I.Ch.E. Journal, 25, No. 4, p. 653
(1979).
14
Ely, J.F. and Hanley, H.J.M., "A Computer Program for the Prediction of
Viscosity and Thermal Conductivity in Hydrocarbon Mixtures", NBS
Technical Note 1039.
15
Twu, C.H., I.E.C. Proc Des & Dev, 24, p. 1287 (1985).
16 Reid,
R.C., Prausnitz, J.M., Poling, B.E., "The Properties of Gases & Liquids",
McGraw-Hill, Inc., 1987.
A-75
A-76
References
17
Woelflin, W., "Viscosity of Crude-Oil Emulsions", presented at the spring
meeting, Pacific Coast District, Division of Production, Los Angeles, Calif.,
Mar. 10, 1942.
18 Gambill,
W.R., Chem. Eng., March 9, 1959.
19
API Technical Data Book, Petroleum Refining, Fig. 9A1.4, p. 9-15, 5th Edition
(1978).
20
Keenan, J. H. and Keyes, F. G., Thermodynamic Properties of Steam, Wiley
and Sons (1959).
21 Perry,
R. H.; Green, D. W.; “Perry’s Chemical Engineers’ Handbook Sixth
Edition”, McGraw-Hill Inc., (1984).
22 Passut,
C. A.; Danner, R. P., “Development of a Four-Parameter
Corresponding States Method: Vapour Pressure Prediction”,
Thermodynamics - Data and Correlations, AIChE Symposium Series; p. 3036, No. 140, Vol. 70.
A-76
Petroleum Methods/Correlations
B-1
B Petroleum Methods/
Correlations
B.1 Introduction .....................................................................................2
B.2 Characterization Method ................................................................2
B.2.1
B.2.2
B.2.3
B.2.4
B.2.5
B.2.6
B.2.7
Generate a Full Set of Working Curves ...................................3
Light Ends Analysis..................................................................4
Auto Calculate Light Ends........................................................6
Determine TBP Cutpoint Temperatures ...................................7
Graphically Determine Component Properties ........................8
Calculate Component Critical Properties .................................8
Correlations..............................................................................9
B.3 References.....................................................................................10
B-1
B-2
Introduction
B.1 Introduction
This appendix is a supplement to Chapter 4 - HYSYS Oil Manager.
Included in this appendix is the general procedure used by HYSYS to
characterize an oil and a list of correlations used in the Oil Manager.
B.2 Characterization Method
The procedure HYSYS uses to convert your assay data into a series of
petroleum hypocomponent involves four major internal
characterization steps:
1.
Based on your input curves, HYSYS calculates a detailed set of full
range Working Curves that include the true boiling point (TBP)
temperature, molecular weight, density and viscosity behaviour.
2.
Next, by using either a default or user-supplied set of cutpoint
temperatures, the corresponding fraction for each hypocomponent
is determined from the TBP working curve.
3.
The normal boiling point (NBP), molecular weight, density and
viscosity of each hypocomponent are graphically determined from
the working curves.
4.
For each hypocomponent, HYSYS calculates the remaining critical
and physical properties from designated correlations, based upon
the component’s NBP, molecular weight, and density.
Knowledge of the four phases of the characterization process provide a
better understanding of how your input data influences the final
outcome of your characterization. The following sections detail each
step of the calculation.
B-2
Petroleum Methods/Correlations
B-3
B.2.1 Generate a Full Set of Working Curves
To ensure accuracy, a true boiling point (TBP) curve and associated
molecular weight, density, and viscosity property curves are required for
the characterization calculations. HYSYS takes whatever input curves
you have supplied, and interpolates and extrapolates them as necessary
to complete the range from 0 to 100%. These full range curves are
referred to as the working curves.
If you supply an ASTM D86, ASTM D1160, or EFV distillation curve as
input, it is automatically converted to a TBP distillation curve. On the
other hand, if you do not have any distillation data, supplying two of the
three bulk properties (molecular weight, density, or Watson (UOP) K
factor) allows HYSYS to calculate an average1 TBP distillation curve.
Physical property curves that were not supplied are calculated from
default correlations designed to model a wide variety of oils, including
condensates, crude oils, petroleum fractions, and coal-tar liquids. If you
supply a bulk molecular weight or bulk density, the corresponding
physical property curve (either user-supplied or generated) is smoothed
and adjusted such that the overall property is matched. A typical TBP
curve is illustrated below.
Figure B.1
FBP
Temperature
Default values of the IBP and
FBP can be changed on the
Boiling Ranges view. Refer to
Section 4.4 - Oil
Characterization View.
IBP
0
Percent Distilled
100
B-3
B-4
Characterization Method
B.2.2 Light Ends Analysis
HYSYS uses your Light Ends data to either define or replace the low
boiling portion of your TBP, ASTM D86 or ASTM D1160 curve with
discrete pure components. HYSYS does not require that you match the
highest boiling point light-end with the lowest boiling point
temperature on the TBP curve.
Using the sample Light Ends analysis shown here, HYSYS replaces the
first portion of the TBP working curve to the assay percentage just past
the boiling point of n-pentane (approximately 95°F or 36°C) or 11.3 vol%
(the cumulative light ends total), whichever is greater. The new TBP
curve would include the Light Ends Free portion of the original sample
beginning at 0% distilled with the associated IBP representing the
remaining portion of the original sample.
Three possible Light Ends/Assay situations can exist as depicted in the
next three figures. In the following figures:
•
Point A represents the boiling point of the heaviest light-end, nPentane in this example.
Point B represents the temperature at which the total Light Ends
percentage intersects the TBP working curve.
•
If points A and B coincide exactly as shown in Figure B.2, HYSYS assigns
the TBP working curve’s IBP equal to the boiling point of the heaviest
light end and normalizes the remaining portion of the TBP curve with
the light ends removed. All points that lie below point B on the curve are
eliminated.
Figure B.2
Temperature
FBP
AB
NBP
nC5
IBP
B-4
Portion of Original Assay that will be Renormalized to be on a Light Ends Free Basis
0 Cumulative
Light Ends
Percent Distilled
100
Petroleum Methods/Correlations
B-5
Figure B.3 depicts the situation that may arise from inconsistent data or
from a poor extrapolation of the IBP. These situations are corrected by
assuming that the Light Ends analysis is correct and that the error exists
in the internal TBP curve. In the following figure, Point A (boiling point
of the heaviest light end component) lies below Point B (internal TBP
curve temperature associated with your cumulative light ends
percentage) on the internal TBP working curve. HYSYS replaces point B
(the Light Ends free IBP) by a point that uses the cumulative light ends
percentage and the normal boiling point of the heaviest light ends
component. The Light Ends free portion of the curve is smoothed before
normalizing.
Figure B.3
Temperature
FBP
NBP
nC5
IBP
A
B
Portion of Original Assay that will be Renormalized to be on a Light Ends Free Basis
0 Cumulative Light
Ends % Distilled
Percent Distilled
100
The next figure shows the boiling point of the heaviest light-end
occurring at an assay percentage greater than the cumulative Light Ends
total. HYSYS corrects this situation by successively eliminating TBP
working curve points from point B up to the first temperature point
greater than the heaviest light end temperature (Point A).
B-5
B-6
Characterization Method
For example, if in the following figure Point B represents 5% and Point A
represents 7%, the new TBP curve (which is light ends free) is stretched,
i.e., what was 93% of the assay (determined from point A) is now 95% of
the assay. As in the previous case, Point A’s temperature is assigned to
the new TBP curve’s IBP, and the Light Ends free portion is smoothed
and normalized.
Figure B.4
Temperature
FBP
Portion of Original Assay that will be
Renor-malized to be on a Light Ends
Free Basis
A
NBP
nC5
B
Portion of TBP that is eliminated due to
inconsistencies between the Distillation and
Light-Ends Analyses
IBP
0
Cumulative Light
Ends % Distilled
Percent Distilled
100
B.2.3 Auto Calculate Light Ends
HYSYS' Auto Calculate Light Ends procedure internally plots the boiling
points of the defined components on the TBP working curve and
determines their compositions by interpolation. HYSYS adjusts the total
Light Ends fraction such that the boiling point of the heaviest light end is
at the centroid volume of the last Light Ends component. The figure
below illustrates the Auto Calculate Light Ends removal procedure.
Figure B.5
Temperature
FBP
Cumulative
Light Ends
% Distilled
NBP nC5
iC5
nC4
New IBP point for the TBP curve
Centroid Volume of the Last
Light-End Component
iC4
IBP
Portion of Original Assay that will be Renormalized
to be on a Light Ends Free Basis
0 iC4 nC4 iC5 nC5
100
Percent Distilled
B-6
Petroleum Methods/Correlations
B-7
B.2.4 Determine TBP Cutpoint Temperatures
You may specify the hypocomponent breakdown by supplying a
number of cutpoint temperatures and the corresponding number of
cuts for each temperature range, or you may let HYSYS calculate an
optimal set of cutpoints for you based upon the overall number of
hypocomponent you have designated. The characterization process
then uses its TBP working curve and the specified set of TBP cutpoints to
determine the fraction of each hypocomponent on the input curve
basis.
In Figure B.6, four components are generated from the TBP curve using
five TBP cutpoints of equal temperature increment. Refer to Section 4.6
- Hypocomponent Generation for more details.
Figure B.6
Temperature
T4
T3
T2
T1
IBP CUT1
0
CUT2
CUT3
Percent Distilled
CUT4
100
B-7
B-8
Characterization Method
B.2.5 Graphically Determine Component
Properties
After the cutpoints and the fraction of each hypocomponent are known,
the average boiling point may be determined. This is the normal boiling
point (NBP), which is calculated for each component by equalizing the
areas between the TBP curve and a horizontal line representing the NBP
temperature. This is shown in the figure below, with the grey areas
representing the equalized areas. The average molecular weight,
density, and viscosity of each hypocomponent are subsequently
calculated from the corresponding smoothed working curves for
molecular weight, density and viscosity.
Figure B.7
Temperature
T4
T3
T2
T1
CUT1
IBP
0
CUT2
CUT3
CUT4
100
Percent Distilled
B.2.6 Calculate Component Critical Properties
Knowing the normal boiling point, molecular weight, and density
enables HYSYS to calculate the remaining physical and thermodynamic
properties necessary to completely define the petroleum
hypocomponent. These properties are estimated for each
hypocomponent using default or user-selected correlations as outlined
in Section B.2.7 - Correlations.
B-8
Petroleum Methods/Correlations
B-9
B.2.7 Correlations
The range of applicability for the critical property correlations are
explained below:
Critical Property
Correlation
Range of Applicability
Lee-Kesler
These equations yield nearly identical results to those obtained using the graphical
correlations found in the API Data Book for boiling temperatures below 1250°F
(677°C). The equations are modified to extend beyond this range, but an upper limit is
not given by the authors.
Cavett
The author does not present any reference as to which data were used for the
development of the correlations or their limitations. Experience has proven these
correlations to produce very good results for fractions whose API gravity is greater
than zero or for highly aromatic and naphthenic fractions such as coal tar liquids.
Riazi-Daubert
In the boiling point range 0 - 602°F (-18 - 317°C), these correlations perform slightly
better than other methods. Their most serious drawback is the limitation of the boiling
point to 855°F (457°C) for the calculation of critical pressure and molecular weight.
Nokay
Limitations for these correlations are not presented in the original publications. The
critical temperature and molecular weight correlations are particularly good for highly
aromatic or naphthenic systems as shown in a paper by Newman, "Correlations
Evaluated for Coal Tar Liquids".
Roess
The main limitation of these correlations is that they should not be used for fractions
heavier than C20 (650°F, 343°C). They highly underestimate critical temperatures for
heavier fractions and should not be used for heavy oil applications.
Edmister
These equations are very accurate for pure components, but are restricted to
condensate systems with a limited amount of isomers. Edmister acentric factors tend
to be lower than Lee-Kesler values for fractions heavier than C20 (650°F, 343°C). It is
recommended that application of the Edmister equation be restricted to the range
below C20.
Bergman
These correlations were developed for lean gases and gas condensates with
relatively light fractions, thereby limiting their general applicability to systems with
carbon numbers less than C15.
SpencerDaubert
This family of correlations is a modification of the original Nokay equations with a
slightly extended range of applicability.
Rowe
These equations were presented for estimating boiling point, critical pressure and
critical temperature of paraffin hydrocarbons. Carbon number, which is used as the
only correlating variable, limits the range of applicability to lighter paraffinic systems.
Standing
The data of Matthews, Roland and Katz was used to develop these correlations.
Molecular weight and specific gravity are the correlating variables. Although Standing
claims the correlations are for C7+ fractions, they appear to be valid for narrower
boiling point cuts as well. The correlations should be used with caution for fractions
heavier than C25 (841°F, 450°C).
Lyderson
These correlations are based on the PNA (Paraffin/Napthene/Aromatic) concept
similar to Peng-Robinson PNA.
B-9
B-10
References
Critical Property
Correlation
Range of Applicability
Bergman
This method is limited to components whose gravity does not exceed 0.875 because
of the form of the PNA equations. Acentric factors for fractions heavier than C20 are
considerably higher than those estimated from either the Edmister or Lee-Kesler
equation. These correlations are included primarily for completeness and should not
be used for fluids containing fractions heavier than C20.
Yarborough
This method is only for use in the prediction of specific gravity of hydrocarbon
components. Carbon number and aromaticity are the correlating variables for this
equation. The Yarborough method assumes that the C7+ molecular weight and
specific gravity are measured. It also assumes that the mole fractions are measured
from chromatographic analysis (paraffin molecular weights are assumed to convert
weight to mole fractions).
Katz-Firoozabadi
These correlations are only available for the prediction of molecular weight and
specific gravity. Normal boiling point is the only correlating variable and application
should be restricted to hydrocarbons less than C45.
Mathur
Limitations for these correlations are not published by the author. These equations
produce excellent results for highly aromatic mixtures such as coal-tar liquids, but are
not rigorously examined for highly paraffinic systems.
Penn State
These correlations are similar to Riazi-Daubert correlations and should have
approximately the same limitations.
Aspen
These correlations yield results quite close to the Lee-Kesler equations, but tend to
produce better results for aromatic systems. Limitations for these equations are not
available, but the Lee-Kesler limitations should provide a good guide.
Hariu Sage
These correlations were developed for estimating molecular weight from boiling point
and specific gravity utilizing the Watson Characterization Factor, Kw. It provides
reasonable extrapolation to boiling points greater than 1500°F (816°C) and is more
accurate than the Lee-Kesler molecular weight correlation.
B.3 References
1
B-10
Whitson, C. H., “Characterizing Hydrocarbon Plus Fractions”, Society of
Petroleum Engineers Journal, August 1983.
Amines Property Package
C-1
C Amines Property Package
C.1 Amines Property Package..............................................................2
C.2 Non-Equilibrium Stage Model ........................................................5
C.3 Stage Efficiency ..............................................................................7
C.3.1 Non-Equilibrium Stage Model ..................................................8
C.4 Equilibrium Solubility .....................................................................9
C.4.1 Kent & Eisenberg Model ..........................................................9
C.4.2 Li-Mather Electrolyte Model ...................................................12
C.5 Phase Enthalpy .............................................................................18
C.6 Simulation of Amine Plant Flowsheets .......................................19
C.6.1
C.6.2
C.6.3
C.6.4
C.6.5
Solving the Columns..............................................................19
Converging the Contactor......................................................20
Converging the Regenerator .................................................21
Recycle Convergence............................................................21
Operating Conditions .............................................................22
C.7 Program Limitations .....................................................................23
C.7.1 Range of Applicability ............................................................23
C.8 References.....................................................................................24
C-1
C-2
Amines Property Package
C.1 Amines Property Package
The Amines Property Package is a special option available for HYSYS.
For more information on this option or get information on other HYSYS
additions please contact your Hyprotech Agent.
The removal of acid gases such as hydrogen sulphide (H2S) and carbon
dioxide (CO2) from process gas streams is often required in natural gas
plants and in oil refineries. There are many treating processes available.
However, no single process is ideal for all applications. The initial
selection of a particular process may be based on feed parameters such
as composition, pressure, temperature and the nature of the impurities,
as well as product specifications.
Final selection is ultimately based on process economics, reliability,
versatility and environmental constraints. Clearly the selection
procedure is not a trivial matter and any tool that provides a reliable
mechanism for process design is highly desirable.
Acid gas removal processes using absorption technology and chemical
solvents are popular, particularly those using aqueous solutions of
alkanolamines. The Amines Property Package is a special property
package designed to aid in the modeling of alkanolamine treating units
in which H2S and CO2 are removed from gas streams. The Property
Package contains data to model the absorption/desorption process
where aqueous solutions of single amines - monoethanolamine (MEA),
diethanolamine (DEA), methyldiethanolamine (MDEA),
triethanolamine (TEA), 2,2’-hydroxy-aminoethylether (DGA), or
diisopropanolamine (DIPA) and aqueous solutions of blended amines MEA/MDEA or DEA/MDEA are used.
C-2
Amines Property Package
C-3
Figure C.1 shows the conventional process configuration for a gas
treating system that uses aqueous alkanolamine solutions. The sour gas
feed is contacted with amine solution counter-currently in a trayed or
packed absorber. Acid gases are absorbed into the solvent that is then
heated and fed to the top of the regeneration tower. Stripping steam
produced by the reboiler causes the acid gases to desorb from the amine
solution as it passes down the column. A condenser provides reflux and
the acid gases are recovered overhead as a vapour product. Lean amine
solution is cooled and recycled back to the absorber. A partially
stripped, semi-lean amine stream may be withdrawn from the
regenerator and fed to the absorber in the split-flow modification to the
conventional plant flowsheet. A three-phase separator or flash tank may
be installed at the outlet of the absorber to permit the recovery of
dissolved and entrained hydrocarbons and to reduce the hydrocarbon
content of the acid gas product.
Figure C.1
C-3
C-4
Amines Property Package
The design of amine treating units involves the selection of the
following:
•
•
•
•
•
the process configuration
the amine type and concentration
the solution circulation rate
the reboiler heat requirements
the operating pressures and temperatures.
The mechanical tray design and the number of stages in the contactor
are known to affect the process performance and are particularly
important in selective absorption applications.
Amine treating units were designed in the past using hand calculations
and operating experience. Design conditions were typically chosen
within a conservative range to cover the deficiencies in the data used in
the hand calculations. Simulation is one means of obtaining values for
the key design variables in the process, and is generally used to confirm
the initial design obtained by the above methods.
Rules-of-thumb do not exist for the design of selective absorption
applications since operating experience is limited. Furthermore, the
process is generally controlled by reaction kinetics and cannot be
designed on the basis of chemical equilibrium alone. The simulation
program must be relied upon as a predictive tool in these cases.
The AMSIM program uses technology developed by DB Robinson &
Associates Ltd. to model the equilibrium solubility of acid gases in
aqueous amine solutions. A new nonequilibrium stage model which is
based on the stage efficiency concept is used to simulate the
performance of contactors and regenerators. A list of reference articles
on the research leading to the development of AMSIM can be found at
the end of this section. The best data known to exist is used to determine
the component properties in the AMSIM databank.
The AMSIM models is designed for one amine or two amines. When two
amines are selected, the Amines property package expects both amines
to have a composition or both amines to be zero. You cannot specify
one amine composition to be greater than zero and the other to be equal
to zero. It is suggested that instead of specifying one amine to be zero,
input a very small composition value for said amine.
C-4
Amines Property Package
C-5
C.2 Non-Equilibrium Stage Model
A non-equilibrium stage model developed to simulate the multicomponent multistage mass transfer process encountered in an amine
treating unit is used in the Amines Property Package.
The generalized stage model shown in Figure C.2 gives the flow
geometry and nomenclature for an individual stage in a column. The
fundamental concept used is that the rate of absorption/desorption of
acid gases to/from the amine solution must be considered as a
mass-transfer rate process. This rate process depends on the
equilibrium and kinetic parameters that describe the acid gas/amine
system.
The model incorporates a modified Murphree-type vapour efficiency to
account for the varying mass-transfer rates of individual acid gas
components. The acid gas stage efficiencies are, in turn, functions of
mass-transfer coefficients and the mechanical design of the tray.
C-5
C-6
Non-Equilibrium Stage Model
When the generalized stage model is extended to the multistage case,
the resulting column flow geometry and nomenclature is shown in
Figure C.2. The resulting set of balance equations that characterize the
multistage unit are given in Section C.4 - Equilibrium Solubility. This
set of equations must be solved for each column in the flowsheet. A
modified Newton-Raphson method is used to solve the rigorous nonlinear stage equations simultaneously for temperature, composition
and phase rates on each stage in a column.
Figure C.2
C-6
Amines Property Package
C-7
C.3 Stage Efficiency
The stage efficiency as defined under the Amines property package
option is given by:
( V j + SV j )Y j – V j + 1 Y ij + 1
η = ------------------------------------------------------------------------( V j + SV j )K 1j X ij – V j + 1 Y ij + 1
where:
(C.1)
η = Stage efficiency
i = Component number
j = Stage number
K = Equilibrium ratio
V = Molar flow rate of vapour
X = Mole fraction in liquid phase
Y = Mole fraction in vapour phase
The stage efficiency is a function of the kinetic rate constants for the
reactions between each acid gas and the amine, the physico-chemical
properties of the amine solution, the pressure, temperature and the
mechanical tray design variables such as tray diameter, weir height and
weir length.
You may specify the stage efficiencies or have them calculated in HYSYS.
If the Amines option is selected, HYSYS always uses stage-component
efficiencies. Note that the efficiencies used are only for H2S and C02
components. If the efficiencies are not specified for the column, HYSYS
calculates efficiencies based on the tray dimensions specified in the
Amines page of the Column view. If no tray dimensions are specified,
HYSYS uses the default tray dimensions to calculate the stage
efficiencies. These are real stages, not ideal stages.
C-7
C-8
Stage Efficiency
C.3.1 Non-Equilibrium Stage Model
Overall Material Balance
F j + L j – 1 – ( L j + SL j ) – ( V j + SV j ) = 0
(C.2)
Component Material Balance
F j z ij + L j – 1 x ij – 1 + V j + 1 Y ij + 1 – ( L j + SL j )x ij – ( V j + SV j )y ij = 0
(C.3)
Energy Balance
F j H Fj + Q j + L j – 1 h j – 1 + V j + 1 H j + 1 – ( L j + SL j )h j – ( V j + SV j )H i = 0
(C.4)
Equilibrium Relationship
η ij K ij x ij ( V j + SV j ) – ( V j + SV j )y ij + ( 1 – η ij )V j + 1 y ij + 1 = 0
(C.5)
Summation Equation
∑ yij – 1.0
C-8
= 0
(C.6)
Amines Property Package
C-9
C.4 Equilibrium Solubility
C.4.1 Kent & Eisenberg Model
A model based on the Kent and Eisenberg approach is used to correlate
the equilibrium solubility of acid gases in the amine solutions. The
reference articles contain experimental data that were used to validate
the solubility model. Additional unpublished data for DEA, MDEA,
MEA/MDEA, and DEA/MDEA systems have also been incorporated.
Improvements were made to the model to extend the reliable range to
mole loadings between 0.0001 and 1.2. A proprietary model was
developed to predict the solubility of acid gas mixtures in tertiary amine
solutions. Solubilities of inert components such as hydrocarbons are
modeled using a Henry’s constant adjusted for ionic strength effects.
The prediction of equilibrium ratios or K-values involves the
simultaneous solution of a set of non-linear equations that describe the
chemical and phase equilibria and the electroneutrality and mass
balance of the electrolytes in the aqueous phase. These equations are
provided below. The model is used to interpolate and extrapolate the
available experimental solubility data in the Amines Property Package.
For tertiary amines that do not form carbamate, the equations involving
that ionic species are eliminated from the model.
These equations are shown as follows:
Chemical Reactions
R 1 R 2 NH + H 2 O ⇔ R 1 R 2 NH 2+ + OH -
(C.7)
R 1 R 2 R 3 N + H 2 O ⇔ R 1 R 2 R 3 NH + + OH -
(C.8)
R 1 R 2 NH + CO 2 ⇔ R 1 R 2 NCOO - + H +
(C.9)
H 2 O ⇔ H + + OH -
(C.10)
C-9
C-10
Equilibrium Solubility
Chemical Reactions
H 2 S ⇔ H + + HS -
(C.11)
CO 2 + H 2 O ⇔ H + + HCO 3-
(C.12)
HS - ⇔ H + + S =
(C.13)
HCO 3- ⇔ H + + CO 3=
(C.14)
[ H + ] [ R 1 R 2 NH ]
K 1 = -------------------------------------[ R 1 R 2 NH 2+ ]
(C.15)
[ H + ] [ R1 R2 R3 N ]
K 2 = ---------------------------------------[ R 1 R 2 R 3 NH + ]
(C.16)
[ HCO 3- ] [ R 1 R 2 NH ]
K 3 = ----------------------------------------------[ R 1 R 2 NCOO - ]
(C.17)
[ H + ] [ OH - ]
K 4 = ---------------------------[ H2 O ]
(C.18)
[ H + ] [ HS - ]
K 5 = -------------------------[ H2 S ]
(C.19)
[ H + ] [ HCO 3- ]
K 6 = --------------------------------[ CO 2 ] [ H 2 O ]
(C.20)
[ H+ ][ S= ]
K 7 = ---------------------[ HS - ]
(C.21)
[ H + ] [ CO 3= ]
K 8 = ---------------------------[ HCO 3- ]
(C.22)
Equilibrium Relations
C-10
Amines Property Package
C-11
Phase Equilibria
V
yH S φH S P = HH S [ H2 S ]
2
2
(C.23)
2
V
y CO φ CO P = H CO [ CO 2 ]
(C.24)
[ H + ] + [ R 1 R 2 NH 2+ ] + [ R 1 R 2 R 3 NH + ] =
[ OH - ] + [ R 1 R 2 NCOO - ] + [ HCO 3- ] + [ HS - ] + 2 [ CO 3= ] + 2 [ S = ]
(C.25)
2
2
2
Charge Balance
Mass Balance
C 1, 2 – amine = [ R 1 R 2 NH ] + [ R 1 R 2 NH 2+ ] + [ R 1 R 2 NCOO - ]
(C.26)
C 3 – amine = [ R 1 R 2 R 3 N ] + [ R 1 R 2 R 3 NH + ]
(C.27)
C CO = ( C 1, 2 – amine + C 3 –amine )α CO =
2
2
[ CO 2 ] + [ R 1 R 2 NCOO - ] + [ HCO 3- ] + [ CO 3= ]
CH
2S
= ( C 1, 2 – amine + C 3 –amine )α H
[ H 2 S ] + [ HS - ] + [ S = ]
2S
=
(C.28)
(C.29)
C-11
C-12
Equilibrium Solubility
The fugacity coefficient of the molecular species is calculated by the
Peng-Robinson equation of state:
a(T)
RT
p = ----------- – ---------------------------------------------v – b v(v + b) + b( v – b)
(C.30)
a = α ( 0.45724 )R 2 T c2 ⁄ P c
(C.31)
b = ( 0.07780 )RT c ⁄ P c
(C.32)
where:
The temperature-dependent quantity α has the following form.
α 1 ⁄ 2 = 1 + α 1 ( 1 – T r ) + α 2 ( 1 – T r ) ( 0.7 – T r )
(C.33)
The parameters α1 and α2 are substance-dependent and are determined
through rigorous regressions against reliable data.
For mixtures, equation parameters a and b are estimated by the
following mixing rules.
a =
∑i ∑j
xi xj ( ai aj )
( 1 – k ij )
(C.34)
b =
∑i ∑j
bi + bj
x i x j  --------------- ( 1 – l ij )
 2 
(C.35)
0.5
C.4.2 Li-Mather Electrolyte Model
The Amines property package is modified to simulate three phase
behaviour. For the three phase simulation, the K values from the PengRobinson property package were combined with the K values from the
Amines LLE and VLE package.
C-12
Amines Property Package
C-13
The Li-Mather model shows a strong predictive capability over a wide
range of temperatures, pressures, acid gas loadings, and amine
concentrations. AMSIM is capable of simulating processes with blended
solvents made up of any two of six principle amines (MEA, DEA, MDEA,
TEA, DGA and DIPA).
The framework of the thermodynamic model is based on two types of
equilibria: vapour-liquid phase equilibria and liquid-phase chemical
equilibria.
Phase Equilibria
The vapour-liquid equilibria of the molecular species is given by:
V
L
yi Φi P = Hi xi γi
where:
(C.36)
Hi = Henry’s constant
P = system pressure
xi, yi = mole fraction of molecular specied i in the liquid and gas phase
V
Φ i = fugacity coefficient on the gas phase
L
γ i = activity coefficient in the liquid phase
The fugacity coefficient is calculated by the Peng-Robinson equation of
state (Peng and Robinson, 1976):
RT
a(T)
P = ------------ – ------------------------------------------------V – b V( V + b) + b(V – b)
(C.37)
Where the parameters are obtained from the EQUI-PHASE EQUI90TM
program library. The activity coefficient is calculated by the Clegg-Pitzer
equation that is described later in this section.
C-13
C-14
Equilibrium Solubility
Chemical Equilibria
In case of single amine-H2S-CO2-H2O systems, the important chemical
dissociation reactions are as follows:
Chemical Dissociation Reactions
+
Amine ⇔ Amine + H
-
H 2 S ⇔ HS + H
+
+
(C.39)
-
CO 2 + H 2 O ⇔ HCO 3 + H
-
H 2 O ⇔ OH + H
-
-
=
=
+
+
HCO 3 ⇔ CO 3 + H
HS ⇔ S + H
(C.38)
+
+
(C.40)
(C.41)
(C.42)
(C.43)
The chemical equilibrium constants in the acid gas - amine systems play
an important role in the prediction of the equilibrium solubilities of acid
gases in the aqueous amine solutions. The equilibrium constant K can
be expressed by:
K = Πi ( xi yi )
βi
(C.44)
The equilibrium constant is expressed as a function of temperature:
ln K = C 1 + C 2 ⁄ T + C 3 ln T + C 4 T
(C.45)
Henry’s constant has the same function of temperature as that in
equation (C.45). In the liquid phase, there are four molecular species,
Amine, H2O, CO2, H2S and seven ionic species, Amine+, HCO3-, HS-, H+,
OH-, CO3=, S= for the amine-H2S-CO2-H2O system. In the gas phase,
there are only four molecular species, Amine, H2O, CO2 and H2S.
C-14
Amines Property Package
C-15
The determination of the compositions of all molecular and ionic
species in both vapour and liquid phases involves the simultaneous
solution of a set of non-linear equations that describe the phase
equilibria and chemical equilibria, electroneutrality (charge balance)
and mass balance of the electrolytes in the aqueous solution.
The Clegg-Pitzer Equation
The original Pitzer equation (Pitzer, 1973) did not consider the solvent
molecules in the system as interacting particles. Thus it is not suitable
for the thermodynamic description of the mixed-solvent systems. In the
Clegg-Pitzer model, all the species in the system were considered as
interacting particles. The long-range electrostatic term and the shortrange hard-sphere-repulsive term deduced from the McMillan-Mayer’s
statistical osmotic-pressure theory remained unchanged. The excess
Gibbs free energy, gex consists of the long-range Debye-Huckel
electrostatic interaction term, gDH and the short-range Margules
expansions with two- and three-suffix, gs:
g
ex
= g
DH
+g
s
(C.46)
DH
4A x I x
1⁄2
1⁄2
g
--------- = ------------- ln ( 1 + ρI x ) + ∑ ∑ x c x a B ac g ( αI x )
ρ
RT
c
s
g
------- =
RT
(C.47)
a
∑ ∑ aij xi xj + ∑ ∑ ∑ aijk xi xj xk
c
a
i
j
k
(C.48)
s
g
------- = x I ∑ x n ∑ ∑ F c F a W nca + ∑ ∑ x n x n’( A nn’x n’ + A n’n x n )
RT
n
where:
c
a
n n ""
A nn’ = 2a nn’ + 3a n’n
A nn’ = 2a nn’ + 3a nn’n’’
W nca = ( 2w nc + 2w na – w ca + 2u nc + 2u na ) ⁄ 4
C-15
C-16
Equilibrium Solubility
w ij = 2a ij + 3 ⁄ 2 ( a iij + a ijj )
u ij = 3 ⁄ 2 ( a iij – a ijj )
The expressions of activity coefficient for solvent N and ion M+ are as
follows:
3⁄2
2A x I x
1⁄2
ln γ N = ----------------------–
x x B exp ( – αI x ) + x I ( 1 – x N ) ∑ ∑ F c F a W Nca
1 ⁄ 2 ∑ ∑ c a ca
1 + ρI x
c a
c a
– x I ∑ ′x n ∑ ∑ F c F a W nca + ∑ ′x n [ A Nn x n ( 1 – 2x N ) + 2A nN x N ( 1 – x N ) ]
n
c
a
(C.49)
n
– 2 ∑ ′ ∑ ′x n x n’( A nn’x n’ + A n’n x n )
n
n’
1⁄2
ln γ
M
+
2
1⁄2
z M g ( αI x )
– ∑ ∑ x c x a B ca ----------------------------- + ( 1 –
2I x
c
2
I x ( 1 – 2I x ⁄ z M )
2
2
1⁄2
1⁄2
= – z M A x --- ln ( 1 + ρI x ) + ----------------------------------------- + ∑ x a B ma g ( αI x )
1⁄2
ρ
1 + ρI
x
2
zM
⁄
a
1⁄2
2I x ) exp ( – αI x )
a
+ 2 ∑ x n ∑ F a W nMa
n
a
(C.50)
– ∑ x n ( 1 + x I ) ∑ ∑ F c F a W nca – 2 ∑ F a W 2Ma + ∑ ∑ F c F a W 2ca
n
c
a
a
c
a
– 2 ∑ ∑ x n x n’( A nn’x n’ + A n’n x n )
n n’
Where subscripts c, a, n and n’ represent cation, anion and molecular
species, respectively. The subscript 2 in equation (C.50) stands for
water. the total mole fraction of ions (xI) is given by:
xI = 1 – ∑ xn
C-16
(C.51)
Amines Property Package
C-17
The cation and anion fractions Fc and Fa are defined for fully
symmetrical electrolyte systems by
F c = 2x c ⁄ x I
(C.52)
F a = 2x a ⁄ x I
(C.53)
The mole fraction ionic strength Ix is defined as
Ix = 1 ⁄ 2 ∑ zi xI
2
(C.54)
The function of g(x) is expressed by
g ( x ) = 2 [ 1 – ( 1 + x ) exp ( – x ) ] ⁄ x
where:
1⁄2
x = αI x
= 2I
2
(C.55)
1⁄2
I = 1 ⁄ 2 ∑ zi Ci
2
Ax is the Debye-Huckel parameter on a mole fraction basis:
A x = A φ  ∑ C n


where:
1⁄2
(C.56)
Ci, Cn = molar concentrations of the ion i and solvent n, respectively
I = ionic strength in molar concentration
A φ = Debye-Huckel parameter, which is a function of temperature,
density and dielectric constant of the mixed solvents
ρ = related to the hard-core collision diameter, or distance of closest
approach between ions in solution
An’n and Ann’ = interaction parameters between and among the
molecular species, respectively
Bca = hard sphere repulsion parameter between ions
C-17
C-18
Phase Enthalpy
Wnca = the interaction parameter between ions and between ion and
solvent
Parameters An’n, Ann’, Bca and Wnca share the same function of
temperature:
Y = a+b⁄T
(C.57)
The Clegg-Pitzer equations appear to be uncompromisingly long and
contain many terms and parameters. However, it should be pointed out
that only a few parameters were used and many terms, such as the
quaternary terms in the original Clegg-Pitzer equations were omitted in
this model. It can be seen that only Ann’, An’n, Bca and Wnca appear in the
expressions and are treated as adjustable parameters.
In this model, both water and amine are treated as solvents. The
standard state of each solvent is the pure liquid at the system
temperature and pressure. The adopted reference state for ionic and
molecular species is the ideal and infinitely dilute aqueous solution.
C.5 Phase Enthalpy
Vapour phase enthalpy is calculated by the Peng-Robinson equation-ofstate which integrates ideal gas heat capacity data from a reference
temperature. Liquid phase enthalpy also includes the effect of latent
heat of vaporization and heat of reaction.
The absorption or desorption of H2S and CO2 in aqueous solutions of
alkanolamine involves a heat effect due to the chemical reaction. This
heat effect is a function of amine type and concentration, and the mole
loadings of acid gases. The heat of solution of acid gases is obtained by
differentiating the experimental solubility data using a form of the
Gibbs-Helmholtz equation.
C-18
Amines Property Package
C-19
The heat effect which results from evaporation and condensation of
amine and water in both the absorber and regenerator is accounted for
through the latent heat term which appears in the calculation of liquid
enthalpy. Water content of the sour gas feed can have a dramatic effect
on the predicted temperature profile in the absorber and should be
considered, particularly at low pressures.
C.6 Simulation of Amine Plant
Flowsheets
The key to solving an amine treating system lies in the simulation of the
contactor and the regenerator. In both columns, rigorous nonequilibrium stage efficiency calculations are used. In addition, the
contactor efficiency incorporates kinetic reaction and mass transfer
parameters. Only the Amines Property Package can effectively simulate
this system, and only components included in this package should be
used.
C.6.1 Solving the Columns
Follow these general guidelines:
•
•
•
•
•
Ensure that the gas to the Contactor is saturated with water.
Use actual, not ideal, stages.
Change stage efficiencies for CO2 and H2S from their default
values of 1.0 to fractions for the regenerator and the initial
absorber run.
Use calculated efficiencies for subsequent absorber runs as
detailed below.
Change the damping factor from a default value of 1.0 to a
fraction as recommended in the following section. This may be
necessary to prevent oscillation during convergence.
C-19
C-20
Simulation of Amine Plant Flowsheets
C.6.2 Converging the Contactor
Convergence is most readily achieved by first solving with estimated
efficiencies (suggested values are 0.3 for CO2 and 0.6 for H2S), then
requesting calculated efficiencies and restarting the column. To do this,
you must first specify three dimensions for each tray: tray diameter, weir
length and weir height. Specify these parameters in the Amines page of
the Parameters tab in the Column view.
For an existing column, use the actual dimensions. For a design
situation (or when the tray dimensions are unknown) use the Tray
Sizing utility to estimate these parameters. Input the calculated tray
dimensions and select Run. HYSYS will calculate the individual
component efficiencies (H2S, CO2) based on the tray dimensions. Only
single pass trays can be modeled with the Amines Property Package. If
the trays in your column are multipass, you must estimate the
dimensions based on a single pass tray.
After the tray dimensions are specified, the column is recalculated. Note
that efficiencies can be calculated only when using the Amines Property
Package. These values apply specifically to CO2 and H2S. Damping
factors in the range 0.4 - 0.8 usually give the fastest convergence.
Temperatures around the contactor should be as follows:
Contactor Stream
Temperature Range
Feed Gas
65 - 130 °F
Lean MEA, DEA, TEA, MDEA
100 - 120 °F
Lean DGA
140 °F
(lean amine minimum 10 °F > feed gas)
Absorber Bottoms
C-20
120 - 160 °F
Amines Property Package
C-21
C.6.3 Converging the Regenerator
As with the Contactor, efficiencies can be either specified by the user, or
calculated by the program. For the condenser and reboiler, values of 1.0
must be used. For the remaining trays, efficiencies of 0.15 for CO2 and
0.80 for H2S are suggested initial estimates.
The easiest specifications to converge are the stage 1 (condenser)
temperature and the reboiler duty. Following is a guideline for typical
duties.
Amine
Duty, BTU/US Gallon
TEA, MDEA
800
DEA
1,000
MEA
1,200
DGA
1,300
The reboiler temperature should not exceed 280 F to avoid physical
degradation of the amines into corrosive by-products. Regenerators
usually converge best with reflux ratio estimates of 0.5 - 3.0 and
damping factors of 0.2 - 0.5.
C.6.4 Recycle Convergence
The remaining unit operations in the flowsheet are straightforward.
Note that you need a water makeup stream, as indicated in Figure C.1.
Since the lean amine concentration may vary due to water carryover in
the product from the vessels, a water makeup is required to maintain a
desired concentration.
Amine losses in the contactor overhead are usually negligible and the
makeup stream replaces any water lost so the amine concentration in
the recycle does not change significantly during the recycle
convergence. Thus, you can quite easily make an excellent initial
estimate for the lean amine recycle. The phase, of course, is liquid and
the temperature, pressure, total flow rate and composition are known.
Although the composition of CO2 and H2S is unknown, these sour
components have only a very minor impact on the recycle and can
initially be specified to be zero in the recycle stream.
C-21
C-22
Simulation of Amine Plant Flowsheets
C.6.5 Operating Conditions
The Amines property package contains data for the following
alkanolamines and mixtures of alkanolamines.
Amine
HYSYS Name
Monoethanolamine
MEA
Diethanolamine
DEA
Triethanolamine
TEA
Methyldiethanolamine
MDEA
Diglycolamine
DGA
Diisopropanolamine
DIPA
Monoethanolamine/
Methyldiethanolamine Blend
MEA/MDEA
Diethanolamine/
Methlydiethanolamine Blend
DEA/MDEA
Many different amine system designs can be modeled. However, for
both good tower convergence and optimum plant operation, the
following guidelines are recommended:
Lean Amine Strength
Maximum Acid Gas Loading
(Moles Acid Gas/ Mole Amine)
Weight %
CO2
H2S
MEA
15 - 20
0.50
0.35
DEA
25 - 35
0.45
0.30
TEA, MDEA
35 - 50
0.30
0.20
DGA
45 - 65
0.50
0.35
DEA/MDEA*
35 - 50
0.45
0.30
MEA/MDEA*
35 - 50
0.45
0.30
Amine
* Amine mixtures are assumed to be primarily MDEA.
C-22
Amines Property Package
C-23
C.7 Program Limitations
The Amines property package contains correlations of data which
restrict its use to certain conditions of pressure, temperature and
composition. These limitations are given below.
The chemical and physical property data base is restricted to amines
and the following components:
Available Components with Amines Property Package
Acid Gases
CO2, H2S, COS, CS2
Hydrocarbons
CH4 to C12
Olefins
C2=, C3=, C4=, C5=
Mercaptans
M-Mercaptan, E-Mercaptan
Non-Hydrocarbons
H2, N2, O2, CO, H2O
Aromatic
C6H6, Toluene, e-C6h6, m-Xylene
This method does not allow for the use of any hypotheticals.
C.7.1 Range of Applicability
The following table displays the equilibrium solubility limitations that
should be observed when using this property package.
Alkanolamine
Concentration
Acid Gas Partial
Pressure
Temperature
Range (Wt%)
psia
o
MEA
0 - 30
0.00001 - 300
77 - 260
DEA
0 - 50
0.00001 - 300
77 - 260
TEA
0 - 50
0.00001 - 300
77 - 260
MDEA
0 - 50
0.00001 - 300
77 - 260
DGA
50 - 70
0.00001 - 300
77 - 260
DIPA
0 - 40
0.00001 - 300
77 - 260
Amine
F
For amine mixtures, use the values for MDEA (assumed to be the
primary amine).
C-23
C-24
References
C.8 References
C-24
1
Atwood, K., M.R. Arnold and R.C. Kindrick, "Equilibria for the System,
Ethanolamines-Hydrogen Sulfide-Water", Ind. Eng. Chem., 49, 1439-1444,
1957.
2
Austgen, D.M., G.T. Rochelle and C.-C. Chen, "Model of Vapour-Liquid
Equilibria for Aqueous Acid Gas Alkanolamine Systems", Ind. Eng. Chem.
Res., 03, 543-555, 1991.
3
Bosch, H., "Gas-Liquid Mass Transfer with Parallel Reversible Reactions-III.
Absorption of CO2 into Solutions of Blends of Amines", Chem. Eng. Sci., 44,
2745-2750, 1989.
4
Chakravarty, T., "Solubility Calculations for Acid Gases in Amine Blends",
Ph.D. Dissertation, Clarkson College, Potsdam, NY, 1985.
5
Danckwerts, P.V., and M.M. Sharma, "The Absorption of Carbon Dioxide into
Solutions of Alkalis and Amines", The Chemical Engineer, No.202, CE244CE279, 1966.
6
Deshmukh, R.D. and A.E. Mather, "A Mathematical Model for Equilibrium
Solubility of Hydrogen Sulfide and Carbon Dioxide in Aqueous
Alkanolamine Solutions",
7
Chem. Eng. Sci., 36, 355-362, 1981.
8
Dingman, J.C., "How Acid Gas Loadings Affect Physical Properties of MEA
Solutions", Pet. Refiner, 42, No.9, 189-191, 1963.
9
Dow Chemical Company, "Alkanolamines Handbook", Dow Chemical
International, 1964.
10
Isaacs, E.E., F.D. Otto and A.E. Mather, "Solubility of Mixtures of H2S and CO2
in a Monoethanolamine Solution at Low Partial Pressures", J. Chem. Eng.
Data, 25, 118-120, 1980.
11
Jou, F.-Y., A.E. Mather, and F.D. Otto, "Solubility of H2S and CO2 in Aqueous
Methyldiethanolamine Solutions", Ind. Eng. Chem. Process Des. Dev., 21,
539-544, 1982.
Amines Property Package
12
C-25
Jou, F.-Y., F.D. Otto and A.E. Mather, “Solubility of H2S and CO2 in
Triethanolamine Solutions”, Presented at the AIChE Winter National
Meeting, Atlanta, Georgia, March 11-14, 1984.
13 Jou,
F.-Y., F.D. Otto and A.E. Mather, "Solubility of Mixtures of H2S and CO2
in a Methyldiethanolamine Solution", Paper 140b, Presented at the AIChE
Annual Meeting, Miami Beach, Florida, Nov.2-7, 1986.
14
Jou, F.-Y., A.E. Mather and F.D. Otto, "The Solubility of Mixtures of Hydrogen
Sulfide and Carbon Dioxide in Aqueous Methyldiethanolamine Solutions",
Submitted to The Canadian Journal of Chemical Engineering, 1992.
15
Kahrim, A. and A.E. Mather, "Enthalpy of Solution of Acid Gases in DEA
Solutions", Presented at the 69th AIChE Annual Meeting, Chicago, Illinois,
Nov.28-Dec.2, 1976.
16
Katz, D.L., D. Cornell, R. Kobayashi, F.H. Poettmann, J.A. Vary, J.R. Elenbaas
and C.F. Weinaug, "Handbook of Natural Gas Engineering", McGraw-Hill,
New York, 1959.
17 Kent,
R.L., and B. Eisenberg, "Better Data for Amine Treating", Hydrocarbon
Processing, 55, No.2, 87-90, 1976.
18
Kohl, A.L. and F.C. Riesenfeld, "Gas Purification", 4th Ed., Gulf Publishing Co.,
Houston, Texas, 1985.
19
Lal, D., E.E. Isaacs, A.E. Mather and F.D. Otto, "Equilibrium Solubility of Acid
Gases in Diethanolamine and Monoethanolamine Solutions at Low Partial
Pressures", Proceedings of the 30th Annual Gas Conditioning Conference,
Norman, Oklahoma, March 3-5, 1980.
20 Lawson,
J.D., and A.W. Garst, "Gas Sweetening Data:Equilibrium Solubility of
Hydrogen Sulfide and Carbon Dioxide in Aqueous Monoethanolamine and
Aqueous Diethanolamine Solutions", J. Chem. Eng. Data, 21, 20-30, 1976.
21
Lawson, J.D., and A.W. Garst, "Hydrocarbon Gas Solubility in Sweetening
Solutions: Methane and Ethane in Aqueous Monoethanolamine and
Diethanolamine", J. Chem Eng. Data, 21, 30-32, 1976.
22
Lee, J.I., F.D. Otto, and A.E. Mather, "Solubility of Carbon Dioxide in Aqueous
Diethanolamine Solutions at High Pressures", J. Chem. Eng. Data, 17, 465468, 1972.
23
Lee, J.I., F.D. Otto, and A.E. Mather, "Solubility of Hydrogen Sulfide in
Aqueous Diethanolamine Solutions at High Pressures", J. Chem. Eng. Data,
18, 71-73, 1973a.
24 Lee,
J.I., F.D. Otto, and A.E. Mather, "Partial Pressures of Hydrogen Sulfide
over Aqueous Diethanolamine Solutions", J. Chem. Eng. Data, 18, 420,
1973b.
C-25
C-26
References
25
Lee, J.I., F.D. Otto, and A.E. Mather, "The Solubility of Mixtures of Carbon
Dioxide and Hydrogen Sulphide in Aqueous Diethanolamine Solutions",
Can. J. Chem. Eng., 52, 125-127, 1974a.
26 Lee,
J.I., F.D. Otto and A.E. Mather, "The Solubility of H2S and CO2 in
Aqueous Monoethanolamine Solutions", Can. J. Chem. Eng., 52, 803-805,
1974b.
27
Lee, J.I., F.D. Otto and A.E. Mather, "Solubility of Mixtures of Carbon Dioxide
and Hydrogen Sulfide in 5.0 N Monoethanolamine Solution", J. Chem. Eng.
Data, 20, 161-163, 1975.
28
Lee, J.I., F.D. Otto and A.E. Mather, "Equilibrium in Hydrogen SulfideMonoethanolamine-Water System", J.Chem. Eng. Data, 21, 207-208, 1976a.
29
Lee, J.I., F.D. Otto and A.E. Mather, "The Measurement and Prediction of the
Solubility of Mixtures of Carbon Dioxide and Hydrogen Sulphide in a 2.5 N
30
Monoethanolamine Solution", Can. J. Chem. Eng., 54, 214-219, 1976b.
31
Lee, J.I., F.D. Otto and A.E. Mather, "Equilibrium Between Carbon Dioxide
and Aqueous Monoethanolamine Solutions", J. Appl. Chem. Biotechnol.,
26,
32
541-549, 1976c.
33 Lee,
J.I. and A.E. Mather, "Solubility of Hydrogen Sulfide in Water", Ber.
Bunsenges z. Phys. Chem., 81, 1020-1023, 1977.
34
Mason, D.M. and R.Kao, "Correlation of Vapor-Liquid Equilibria of Aqueous
Condensates from Coal Processing" in Thermodynamics of Aqueous
Systems with Industrial Applications, S.A. Newman, ed., ACS Symp. Ser.,
133, 107-139, 1980.
35
Murzin, V.I., and I.L. Leites, "Partial Pressure of Carbon Dioxide Over Its
Dilute Solutions in Aqueous Aminoethanol", Russian J. Phys. Chem., 45,
230-231, 1971.
36
Nasir, P. and A.E. Mather, "The Measurement and Prediction of the Solubility
of Acid Gases in. Monoethanolamine Solutions at Low Partial Pressures",
Can. J. Chem. Eng., 55, 715-717, 1977.
37 Otto,
F.D., A.E. Mather, F.-Y. Jou, and D. Lal, "Solubility of Light Hydrocarbons
in Gas Treating Solutions", Presented at the AIChE Annual Meeting, Paper
21b, San Francisco, California, November 25-30, 1984.
C-26
38
Peng, D.-Y., and D.B. Robinson, "A New Two-Constant Equation of State",
Ind. Eng. Chem. Fundam., 15, 59-64, 1976.
39
Rangwala, H.A., B.R. Morrell, A.E. Mather and F.D. Otto, "Absorption of CO2
into Aqueous Tertiary Amine/MEA Solutions", The Canadian Journal of
Chemical Engineering, 70, 482-490, 1992.
Amines Property Package
40
C-27
Tomcej, R.A. and F.D. Otto, "Computer Simulation and Design of Amine
Treating Units", Presented at the 32nd Canadian Chemical Engineering
Conference, Vancouver, British Columbia, Oct.3-6, 1982.
41 Tomcej,
R.A., F.D. Otto and F.W. Nolte, "Computer Simulation of Amine
Treating Units", Presented at the 33rd Annual Gas Conditioning
Conference, Norman,
42
Oklahoma, March 7-9, 1983.
43
Tomcej, R.A., "Simulation of Amine Treating Units Using Personal
Computers", Presented at the 35th Canadian Chemical Engineering
Conference, Calgary, Alberta, Oct.5-8, 1985.
44
Tomcej, R.A. and F.D. Otto, "Improved Design of Amine Treating Units by
Simulation using Personal Computers", Presented at the World Congress III
of Chemical Engineering, Tokyo, Japan, September 21-25, 1986.
45 Tomcej,
R.A., D. Lal, H.A. Rangwala and F.D. Otto, "Absorption of Carbon
Dioxide into Aqueous Solutions of Methyldiethanolamine", Presented at
the AIChE Annual Meeting, Miami Beach, Florida, Nov.2-7, 1986.
46
Tomcej, R.A., F.D. Otto, H.A. Rangwala and B.R. Morrell, "Tray Design for
Selective Absorption", Presented at the 37th Annual Laurance Reid Gas
Conditioning Conference, Norman, Oklahoma, March 2-4, 1987.
47
Union Carbide Corporation, "Gas Treating Chemicals", Union Carbide
Petroleum Processing, Chemicals and Additives, 1969.
48 Versteeg,
G.F., J.A.M. Kuipers, F.P.H. Van Beckum and W.P.M. Van Swaaij,
"Mass Transfer with Complex Reversible Chemical Reactions - I. Single
Reversible Chemical Reaction", Chem. Eng. Sci., 44, 2295-2310, 1989.
49
Winkelman, J.G.M., S.J. Brodsky and A.A.C.M. Beenackers, "Effects of Unequal
Diffusivities on Enhancement Factors of Reversible Reactions: Numerical
Solutions and Comparison with Decoursey’s Method", Chem. Eng. Sci., 47,
485-489, 1992.
50
Zhang, Dan D., Gordon X. Zhao, H.-J. Ng, Y.-G. Li and X.-C. Zhao, “An
Electrolyte Model for Amine Based Gas Sweetening Process Simulation”,
Preceeding of the 78th GPA Annual Convention, p25, 1999.
51
Zhange, Dan D., H.-J. Ng and Ray Vledman, “Modeling of Acid Gas Treating
Using AGR Physical Solvent”, Proceeding of the 78th GPA Annual
Convention, p62, 1999.
C-27
C-28
C-28
References
Index
A
Activity Models 2-9, A-6, A-16
See models - Chien Null, Margules, NRTL,
NRTL Options, UNIQUAC, van Laar,
and Wilson
additional specifications 2-17, 2-82
binary interaction parameters 2-38, 2-86
choosing vapour phase model 2-17, A-19, A-35
departure calculations A-47
estimating interaction parameters 2-39
immiscible liquid phases A-21
Amines Property Package 2-12, A-41
Antoine
modified vapour pressure model A-39
parameters tab 2-31
vapour pressure model 2-11, 2-75
ASME Steam A-43
property package 2-12
Assay and Blend Association 4-74
Assay Data
general guidelines 4-32
no distillation data available 4-28, 4-31
physical properties 4-26
standard input 4-29
Assays
characterizing 4-13, 4-16
correlations 4-48
inputting 4-19
light ends 4-33
analysis B-4
auto calculating 4-37, B-6
included 4-34
inputting 4-36
light ends free 4-35
notes 4-50
plotting 4-47
selecting 4-52
types of 4-46
user curves 4-49
working curves 4-46
ASTM D1160. See Laboratory Assay Procedures
ASTM D2887. See Laboratory Assay Procedures
ASTM D86. See Laboratory Assay Procedures
Auto Cut 4-55
B
Basis Manager
component maps tab 6-2
fluid package tab 2-3
hypotheticals tab 3-4
oil manager tab 4-9
reactions tab 5-3
user properties tab 7-3
Blends
auto cutting 4-55
bulk data 4-53
composite plots 4-64
correlations 4-59
cut ranges 4-53
distribution plots 4-63
information 4-60
notes 4-66
oil distributions 4-61
plots summary 4-65
property plots 4-61
Braun K10 2-11, 2-75, A-40
Bubble Point A-67
Bulk Properties 4-26
BWR Equation A-11
C
Cavett Correlation A-47
Chao Seader A-6, A-37
models 2-11, 2-75
parameters tab 2-31
semi-empirical method 2-11, 2-76
Chien Null A-18, A-21
activity model 2-10
parameters tab 2-28, 2-82
Chromatographic Analysis. See Laboratory Assay
Procedures
Chromatographic Assay Input 4-29
Coal Analysis 3-34
Collection (Component Maps) 6-2
Component List Selection 2-12, 2-80
Component Selection 1-12
family filter 1-11
family type filter 1-11
filter options 1-11
general procedure 1-8
property package filter 1-11
tips 1-8
warning messages 2-13
Components
adding 1-5
cloning. See Hypotheticals, cloning library
components
I-1
I-2
Index
creating custom. See Hypotheticals, adding
filtering 1-9
hypotheticals quick access 1-26
incompatible 2-14
manager 1-2
mapping 6-2
master component list 1-2
name format 1-7, 1-9
non recommended 2-13
parameters tab 2-20, 2-82
removing 1-6, 1-13
selected components group 1-6
selection 1-8, 1-12
sorting 1-7, 1-14
substituting 1-6, 1-14
synonyms 1-8
transferring 1-12
viewing 1-7, 1-15
Components Manager 1-2
Conversion Reactions 5-6–5-10
rank 5-37
Correlations
assay 4-48
blend 4-59
critical property B-9
oil characterization 4-70
Cut 4-53
Cut/Blend. See Blends or Oil Characterzation
Cutpoint B-7
D
D86 Interconversion Methods 4-15
D86. See Laboratory Assay Procedures
Density.See Liquid Density or Vapour Density
Dew Point A-67
E
EFV (Equilibrium Flash Vapourization). See
Laboratory Assay Procedures
Eley-Rideal Model 5-23
Enthalpy Basis A-45
tabular 2-61
Enthalpy Departure Calculations A-45
Enthalpy Flash A-68
Entropy Flash A-68
Environments
basis 4-vi
Equations of State (EOS) 2-8, A-9
additional information 2-15, 2-81
I-2
departure calculation A-45
interaction parameters 2-37, 2-84
See models - Generalized Cubic (GCEOS),
Kabadi Danner, Lee-Kesler Plocker,
Peng Robinson, PRSV, Peng
Robinson Options, SRK, SRK Options,
Zudkevitch Joffee.
Equations of State Enthalpy Calculation A-15
Equilibrium Reactions 5-6, 5-11–5-17
fractional approach 5-16
temperature approach 5-16
Esso Tabular A-40
vapour pressure model 2-11, 2-75
Extended NRTL. See NRTL Options
F
Flash Calculations A-65
handling water A-69
temperature-pressure (TP) A-65
vapour fraction A-66
Flow Rate
actual gas A-64
actual volume A-63
as a specification A-64
available A-59
densities, liquid and vapour A-60
liquid volume A-63
mass A-62
molar A-62
standard gas A-63
standard liquid volume A-63
volumetric A-59
Fluid Package
activity models 2-9
adding 2-3
adding - quick start 2-4
adding notes 2-69
advantages 2-2
associated flowsheet 2-4
base property selection 2-8
copy 2-3
delete 2-3
equations of state 2-8
export 2-3
import 2-3
property package selection 2-7
property view 2-7, 2-70
reactions 2-46
stability test 2-42, 2-89
Index
tabular 2-47
See also Tabular Package
Fugacity Coefficients A-51
G
General NRTL. See NRTL Options
Generalized Cubic Equation of State (GCEOS) 2-9
binary coeffs tab 2-32
parameters tab 2-21
Grayson Streed A-6, A-37
parameters tab 2-31
semi-empirical method 2-11, 2-76
H
Henry’s Law A-32
Heterogeneous Catalytic Reactions 5-6, 5-23–5-28
Eley-Rideal 5-23
Langmuir-Hinshelwood 5-23
Mars-van Krevelen Model 5-23
Hypothetical Components. See Hypotheticals
Hypothetical Group
controls 3-12
creating 3-4, 3-11
deleting 3-4
exporting 3-4
group name 3-12
importing 3-4
moving 3-40
moving between 3-5
viewing 3-4, 3-39
Hypotheticals
adding 1-26, 3-13
adding a hypothetical - quick start 3-5
adding hypothetical group 1-26
base properties 3-14
cloning library components 3-5, 3-13, 3-37
critical properties 3-25
deleting 3-13
estimating properties 3-13, 3-26
estimation methods 3-12, 3-16
individual controls 3-13
minimum information required 3-16
moving 3-5
property view 3-23
quick reference 3-5
solid hypotheticals 3-13, 3-32
temperature dependent properties 3-29
UNIFAC structure builder 3-13, 3-20
vapour pressure properties 3-15
I-3
viewing 3-5, 3-13
viewing group. See Hypothetical Group, viewing
I
Ideal Gas Law A-35
departure calculations A-48
Installing
oils 4-13
reaction set 5-39
Interaction Parameters
activity models 2-38, 2-86, A-19
equations of state 2-37, 2-84
estimating A-16
Henry’s Law A-34
K
K/ln(K) Equilibrium Constant 5-14
Kabadi Danner A-9, A-11
equation of state 2-9
parameters tab 2-27
Kinetic Reactions 5-18–5-23
requirements 5-6
L
Laboratory Assay Procedures
ASTM D1160 4-6, 4-28
ASTM D2887 4-6, 4-28
ASTM D86 4-6, 4-28
ASTM D86 and D1160 4-28
chromatographic analysis 4-6, 4-28
assay input 4-29
D2887 interconversion method 4-15
D86 interconversion method 4-15
equilibrium flash vapourization 4-6, 4-28
preparation 4-34
TBP analysis 4-5, 4-28
Langmuir-Hinshelwood Model 5-23
Lee Kesler Plocker 2-9, A-9, A-11
Lee-Kesler Enthalpy A-15, A-37, A-49
Liquid Density A-52
actual A-61
ideal A-61
standard A-61
M
Mapping
collection 6-2
components 6-1
I-3
I-4
Index
target 6-2
transfer options 6-5
Margules A-18, A-26
activity model 2-10
Mars-van Krevelen Model 5-23
MBWR A-43
property package 2-12
N
NBS Steam A-43
property package 2-12
NRTL (Non Random Two Liquid) A-18, A-21, A-27
activity model 2-10
NRTL Options A-21
Extended NRTL 2-10, A-24
General NRTL 2-10, A-24
O
Oil Characterization
analysis methods. See Laboratory Assay
Procedures
bulk blending data 4-53
component critical properties B-8
composite plots 4-64
correlations 4-8, 4-13, 4-48, 4-70
cutting/blending 4-13, 4-51
deleting 4-14
density curves 4-40
determining TBP cutpoints B-7
distribution plots 4-63
FBP 4-14
IBP 4-14
installing oil 4-75
laboratory data corrections 4-8
light ends 4-33–4-34, 4-36, B-4
method B-2
molecular weight curves 4-39
notes 4-74
output settings 4-14
physical property curves 4-7, 4-29
procedure 4-9
property plots 4-61
property view 4-13
purpose 4-3
user properties 4-13, 4-66
viscosity curves 4-41
working curves 4-46
I-4
P
Peng Robinson A-5–A-6, A-9
departure calculations A-45
equation of state 2-9
fugacity coefficient A-51
modelling vapour phase A-35
Peng Robinson Options A-9
PRSV 2-9
Sour PR 2-9, A-14
Physical Properties A-51
Poynting Correction 2-18, A-19
PPDS 2-56–2-57
Property Package
selecting a A-4
Property Packages
See Amines Property Package, Braun K10,
Chao Seader, Esso Tabular, Grayson
Streed, Lee Kesler Plocker, Margules,
MBWR, PRSV, Peng Robinson,
Peng Robinson Options, SRK, SRK Options,
Steam Packages, UNIQUAC, van Laar
and Wilson.
PRSV (Peng Robinson Stryjek Vera) A-5, A-12
equation of state 2-9
parameters tab 2-28
Pseudo Component Generation 4-51
Q
Quality Pressure A-67
R
Reaction Package
adding 5-40
Reaction Rank 5-37
Reaction Sets 5-32
adding 5-33
adding to fluid package 5-33, 5-39
advanced features 5-35
attaching to unit operations 5-39
copying 5-33
deleting 5-33
exporting 5-33, 5-38
importing 5-33, 5-38
quick access 2-46
solver method 5-34
viewing 5-33
Reactions
activating 5-34
Index
adding 5-7
components 5-3–5-4
conversion. See Conversion Reactions
copying 5-7
deactivating 5-34
deleting 5-7
equilibrium. See Equilibrium Reactions
heterogeneous catalytic. See Heterogeneous
Catalytic Reactions
kinetic. See Kinetic Reactions
library reactions 5-5
quick start 5-42
selecting components 5-3–5-4
sets. See Reaction Sets
simple rate. See Simple Rate Reactions
thermodynamic consistency 5-19
viewing 5-7
Redlich Kwong (RK) A-35
departure calculations A-48
S
Simple Rate Reactions 5-29–5-32
requirements 5-6
Solids A-72
Sour PR. See Peng Robinson Options
Sour SRK. See SRK Options
Sour Water Options A-14
See SRK Options and Peng Robinson Options
SRK (Soave Redlich Kwong) A-5–A-6, A-9
departure calculations A-46
equation of state 2-9
fugacity coefficient A-51
modelling vapour phase A-35
SRK Options A-9
See Kabadi Danner and Zudkevitch Joffee
Sour SRK 2-9, A-14
Stability Test 2-40, 2-87
parameters 2-42, 2-89
Steam Packages A-43
See ASME Steam and NBS Steam
Stream Information A-73
Surface Tension A-58
I-5
plotting 2-58
regression 2-62
requirements 2-48
supplying data 2-61
using 2-50
viewing selection 2-57
Target (Component Maps) 6-2
Thermal Conductivity A-56
Transport Properties A-51
U
UNIFAC LLE
interaction parameter estimation 2-39
UNIFAC Property Estimation A-20
UNIFAC Structure Builder 3-20
UNIFAC VLE
interaction parameter estimation 2-39
UNIQUAC (Universal Quasi Chemical Parameters)
2-10, A-18, A-28
User Points 4-56
User Properties 4-49, 4-66, 7-2–7-9
adding 7-3
deleting 7-3
mixing rules 7-7
notes 7-9
viewing 7-3
User Ranges 4-57
V
van Laar A-18, A-30
activity model 2-10
Vapour Density A-53
Vapour Pressure A-67
Vapour Pressure Models 2-11, A-7, A-38
Antoine 2-11, 2-75
Braun K10 2-11, 2-75
Esso Tabular 2-11, 2-75
Virial Equation A-19
departure calculations A-48
modelling vapour phase A-36
Viscosity A-53
liquid phase mixing rules A-55
T
W
Tabular Package 2-47
active properties selection 2-53
data 2-54
enthalpy basis 2-61
library 2-56–2-57
Water A-69
Wilson 2-10, A-18, A-31
parameters tab 2-30
Working Curves B-3
I-5
I-6
Index
Z
Zudkevitch Joffee A-9, A-15
equation of state 2-9
parameters tab 2-28
I-6
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