Introduction to Aspen Plus®

Aspen Technology, Inc.
Reach Your
True
Potential
Introduction to
Aspen Plus
®
Based on Aspen Plus® 10.1
December 1999
®
Septiembre
12, 2001
®
Introduction to Aspen Plus
Slide 1
©1998
AspenTech.
All rights
reserved.
©1998
AspenTech.
All rights
reserved.
Contact Information
• Phone: 888-996-7001 or 617-949-1021
• Email:
support@aspentech.com
• Internet: http://www.aspentech.com
- Technical Support Hotline
- Training
(Contact: Pat Sylvia)
- Customized Support Services
(Contact: Andrea Orchanian)
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 2
©1998 AspenTech. All rights reserved.
Course Agenda - Day 1
1.
Introduction - General Simulation Concepts
2.
The User Interface - Graphical Flowsheet Definition
3.
Basic Input - Getting Around the Graphical User
Interface
4.
Unit Operation Models - Overview of Available Unit
Operations
5.
RadFrac - Multistage Separation Model
6.
Reactor Models - Overview of Available Reactor Types
7.
Cyclohexane Production Workshop
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 3
©1998 AspenTech. All rights reserved.
Course Agenda - Day 2
8.
Physical Properties - Overview of Thermodynamic
Models, Basic Property Analysis and Reporting
9.
Accessing Variables - Making References to Flowsheet
Variables
10. Sensitivity Analysis - Studying Relationships Between
Process Variables
11. Design Specifications - Meeting Process Objectives
12. Fortran Blocks - Use of In-Line Fortran
13. Windows Interoperability - Transferring Data to and from
Other Windows Programs
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 4
©1998 AspenTech. All rights reserved.
Course Agenda - Day 3
14. Heat Exchangers - Heaters and Heat Exchangers
15. Pressure Changers - Pumps, Compressors, Pipes and
Valves
16. Flowsheet Convergence - Convergence Blocks, Tear
Streams and Flowsheet Sequences
17. Full-Scale Plant Modeling Workshop - Simulate a
Methanol Plant
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 5
©1998 AspenTech. All rights reserved.
Additional Topics
18. Maintaining Aspen Plus Simulations - Managing Aspen
Plus Files for Storage and Retrieval
19. Customizing the Look of Your Flowsheet - Creating
Process Flow Diagrams
20. Estimation of Physical Properties - Overview of
Property Estimation
21. Electrolytes - Introduction to the Use of Electrolytes
22. Solids Handling - Overview of the Solids Capabilities
23. Optimization - Optimizing a Flowsheet
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 6
©1998 AspenTech. All rights reserved.
Additional Topics (Continued)
24. RadFrac Convergence - Techniques for Converging
Difficult Columns
25. VCM Workshop
26. ActiveX Automation
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 7
©1998 AspenTech. All rights reserved.
Appendices
A.
Enthalpy Reference and Heat of Reaction
B.
Workshop Instructions
C.
Workshop Results
D.
Final Workshop Hints
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 8
©1998 AspenTech. All rights reserved.
Reach Your
True
Potential
Introduction
Objective:
Introduce general flowsheet simulation concepts and
Aspen Plus features
Introduction to Aspen Plus
®
9
©1998 AspenTech. All rights reserved.
Introduction
• What is flowsheet simulation?
ðUse of a computer program to quantitatively model the
characteristic equations of a chemical process
• Uses underlying physical relationships
- Mass and energy balance
- Equilibrium relationships
- Rate correlations (reaction and mass/heat transfer)
• Predicts
- Stream flowrates, compositions, and properties
- Operating conditions
- Equipment sizes
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 10
©1998 AspenTech. All rights reserved.
Advantages of Simulation
• Reduces plant design time
- Allows designer to quickly test various plant
configurations
•
Helps improve current process
- Answers “what if” questions
- Determines optimal process conditions within given
constraints
- Assists in locating the constraining parts of a process
(debottlenecking)
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 11
©1998 AspenTech. All rights reserved.
General Simulation Problem
What is the composition of stream PRODUCT?
RECYCLE
REACTOR
COOL
FEED
REAC-OUT
COOL-OUT
SEP
PRODUCT
•
To solve this problem, we need:
- Material balances
- Energy balances
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 12
©1998 AspenTech. All rights reserved.
Approaches to Flowsheet Simulation
• Sequential Modular
- Aspen Plus is a sequential modular simulation
program.
- Each unit operation block is solved in a certain
sequence.
• Equation Oriented
- Aspen Custom Modeler (formerly SPEEDUP) is an
equation oriented simulation program.
- All equations are solved simultaneously.
• Combination
- Aspen Dynamics (formerly DynaPLUS) uses the
Aspen Plus sequential modular approach to initialize
the steady state simulation and the Aspen Custom
Modeler (formerly SPEEDUP) equation oriented
approach to solve the dynamic simulation.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 13
©1998 AspenTech. All rights reserved.
Good Flowsheeting Practice
• Build large flowsheets a few blocks at a time.
- This facilitates troubleshooting if errors occur.
• Ensure flowsheet inputs are reasonable.
• Check that results are consistent and realistic.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 14
©1998 AspenTech. All rights reserved.
Important Features of Aspen Plus
• Rigorous Electrolyte Simulation
• Solids Handling
• Petroleum Handling
• Data Regression
• Data Fit
• Optimization
• User Routines
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 15
©1998 AspenTech. All rights reserved.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 16
©1998 AspenTech. All rights reserved.
Reach Your
True
Potential
The User Interface
Objective:
Become comfortable and familiar with the Aspen Plus
graphical user interface
Aspen Plus References:
• User Guide, Chapter 1, The User Interface
• User Guide, Chapter 2, Creating a Simulation Model
• User Guide, Chapter 4,Introduction
Definingtothe
Flowsheet
Aspen
Plus
®
17
©1998 AspenTech. All rights reserved.
The User Interface
Run ID
Title Bar
Menu Bar
Next Button
Select Mode
button
Model
Library
Model Menu
Tabs
Tool Bar
Status Area
Process
Flowsheet
Window
Reference: Aspen Plus User Guide, Chapter 1, The User Interface
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 18
©1998 AspenTech. All rights reserved.
Cumene Flowsheet Definition
RECYCLE
REACTOR
COOL
FEED
REAC-OUT
RStoic
Model
COOL-OUT
Heater
Model
SEP
Flash2
Model
PRODUCT
Filename: CUMENE.BKP
Septiembre 12, 2001
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Introduction to Aspen Plus
Slide 19
©1998 AspenTech. All rights reserved.
Using the Mouse
• Left button click
• Right button click
• Double left click
Select object/field
Bring up menu for
selected object/field,
or inlet/outlet
- Open Data Browser object
sheet
Reference: Aspen Plus User Guide, Chapter 1, The User Interface
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 20
©1998 AspenTech. All rights reserved.
Graphic Flowsheet Operations
To place a block on the flowsheet:
1. Click on a model category tab in the Model Library.
2. Select a unit operation model. Click the drop-down arrow
to select an icon for the model.
3. Click on the model and then click on the flowsheet to
place the block. You can also click on the model icon
and drag it onto the flowsheet.
4. Click the right mouse button to stop placing blocks.
Septiembre 12, 2001
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Introduction to Aspen Plus
Slide 21
©1998 AspenTech. All rights reserved.
Graphic Flowsheet Operations (Continued)
• To place a stream on the flowsheet:
1. Click on the STREAMS icon in the Model Library.
2. If you want to select a different stream type (Material,
Heat or Work), click the down arrow next to the icon and
choose a different type.
3. Click a highlighted port to make the connection.
4. Repeat step 3 to connect the other end of the stream.
5. To place one end of the stream as either a process
flowsheet feed or product, click a blank part of the
Process Flowsheet window.
6. Click the right mouse button to stop creating streams.
Septiembre 12, 2001
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Introduction to Aspen Plus
Slide 22
©1998 AspenTech. All rights reserved.
Graphic Flowsheet Operations (Continued)
• To display an Input form for a Block or a Stream in the Data
Browser:
1. Double click the left mouse button on the object of
interest.
• To Rename, Delete, Change the icon, provide input or view
results for a block or stream:
1. Select object (Block or Stream) by clicking on it with the
left mouse button.
2. Click the right mouse button while the pointer is over the
selected object icon to bring up the menu for that object.
3. Choose appropriate menu item.
Reference: Aspen Plus User Guide, Chapter 4, Defining the Flowsheet
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 23
©1998 AspenTech. All rights reserved.
Automatic Naming of Streams and Blocks
•
Stream and block names can be automatically
assigned by Aspen Plus or entered by the user when
the object is created.
•
•
Stream and block names can be displayed or hidden.
To modify the naming options:
- Select Options from the Tools menu.
- Click the Flowsheet tab.
- Check or uncheck the naming options desired.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 24
©1998 AspenTech. All rights reserved.
Benzene Flowsheet Definition Workshop
Objective: Create a graphical flowsheet
-
Start with the General with English Units Template.
Choose the appropriate icons for the blocks.
Rename the blocks and streams.
VAP1
COOL
VAP2
FEED
COOL
FL1
Flash2
Model
Heater
Model
FL2
LIQ1
Model
When finished, save in backup
format (Run-ID.BKP).
filename: BENZENE.BKP
Septiembre 12, 2001
®
Flash2
Introduction to Aspen Plus
LIQ2
Slide 25
©1998 AspenTech. All rights reserved.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 26
©1998 AspenTech. All rights reserved.
Reach Your
True
Potential
Basic Input
Objective:
Introduce the basic input required to run an Aspen Plus
simulation
Aspen Plus References:
• User Guide, Chapter 3, Using Aspen Plus Help
• User Guide, Chapter 5, Global Information for Calculations
• User Guide, Chapter 6, Specifying Components
• User Guide, Chapter 7, Physical Property Methods
• User Guide, Chapter 9, Specifying Streams
• User Guide, Chapter 10, Unit Operation Models
• User Guide, Chapter 11, Running Your Simulation
Introduction to Aspen Plus
®
27
©1998 AspenTech. All rights reserved.
The User Interface
Menus
- Used to specify program options and commands
Toolbar
- Allows direct access to certain popular functions
- Can be moved
- Can be hidden or revealed using the Toolbars dialog
box from the View menu
Data Browser
- Can be moved, resized, minimized, maximized or
closed
- Used to navigate the folders, forms, and sheets
Septiembre 12, 2001
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Introduction to Aspen Plus
Slide 28
©1998 AspenTech. All rights reserved.
The User Interface (Continued)
Folders
- Refers to the root items in the Data Browser
- Contain forms
Forms
- Used to enter data and view results for the simulation
- Can be comprised of a number of sheets
- Are located in folders
Sheets
- Make up forms
- Are selected using tabs at the top of each sheet
Septiembre 12, 2001
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Introduction to Aspen Plus
Slide 29
©1998 AspenTech. All rights reserved.
The User Interface (Continued)
Object Manager
- Allows manipulation of discrete objects of information
- Can be created, edited, renamed, deleted, hidden, and
revealed
Next Button
- Checks if the current form is complete and skips to the
next form which requires input
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 30
©1998 AspenTech. All rights reserved.
The Data Browser
Go back
Go forward
Next sheet
Comments
Parent button
Units
Previous sheet
Status
Next
Menu tree
Status area
Description area
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 31
©1998 AspenTech. All rights reserved.
Help
• Help Topics
- Contents - Used to browse through the
documentation. The User Guides and Reference
Manuals are all included in the help.
• All of the information in the User Guides is found under
the “Using Aspen Plus” book.
- Index - Used to search for help on a topic using the
-
index entries
Find - Used to search for a help on a topic that
includes any word or words
• “What’s This?” Help
- Select “What’s This?” from the Help menu and then
click on any area to get help for that item.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 32
©1998 AspenTech. All rights reserved.
Functionality of Forms
• When you select a field on a form (click left mouse button
in the field), the prompt area at the bottom of the window
gives you information about that field.
• Click the drop-down arrow in a field to bring up a list of
possible input values for that field.
- Typing a letter will bring up the next selection on the
list that begins with that letter.
• The Tab key will take you to the next field on a form.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 33
©1998 AspenTech. All rights reserved.
Basic Input
• The minimum required inputs (in addition to the
graphical flowsheet) to run a simulation are:
- Setup
- Components
- Properties
- Streams
- Blocks
• These inputs are all found in folders within the Data
Browser.
• These input folders can be located quickly using the
Data menu or the Data Browser buttons on the toolbar.
Septiembre 12, 2001
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Introduction to Aspen Plus
Slide 34
©1998 AspenTech. All rights reserved.
Status Indicators
Symbol
Status
Input for the form is incomplete
Input for the form is complete
No input for the form has been entered. It is optional.
Results for the form exist.
Results for the form exist, but there were calculation
errors.
Results for the form exist, but there were calculation
warnings.
Results for the form exist, but input has changed since
the results were generated.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 35
©1998 AspenTech. All rights reserved.
Cumene Production Conditions
RECYCLE
REACTOR
COOL
FEED
T = 220 F
P = 36 psia
Benzene: 40 lbmol/hr
Propylene: 40 lbmol/hr
REAC-OUT
Q = 0 Btu/hr
Pdrop = 0 psi
COOL-OUT
SEP
P = 1 atm
Q = 0 Btu/hr
T = 130 F
Pdrop = 0.1 psi
C6H6 + C3H6
= C9H12
Benzene Propylene Cumene (Isopropylbenzene)
90% Conversion of Propylene
PRODUCT
Use the RK-SOAVE Property Method
Filename: CUMENE.BKP
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 36
©1998 AspenTech. All rights reserved.
Setup
Most of the commonly used Setup information is entered on
the Setup Specifications Global sheet:
• Flowsheet title to be used on reports
• Run type
• Input and output units
• Valid phases (e.g. vapor-liquid or vapor-liquid-liquid)
• Ambient pressure
Stream report options are located on the Setup Report
Options Stream sheet.
Septiembre 12, 2001
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Introduction to Aspen Plus
Slide 37
©1998 AspenTech. All rights reserved.
Setup Specifications Form
Septiembre 12, 2001
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Introduction to Aspen Plus
Slide 38
©1998 AspenTech. All rights reserved.
Stream Report Options
Stream report options are located on the Setup Report
Options Stream sheet.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 39
©1998 AspenTech. All rights reserved.
Setup Run Types
Run Type
Flowsheet
Standard Aspen Plus flowsheet run including sensitivity studies and optimization.
Flowsheet runs can contain property estimation, assay data analysis, and/or property analysis
calculations.
Assay Data
Analysis
A standalone Assay Data Analysis and pseudocomponent generation run
Data
Regression
A standalone Data Regression run
PROPERTIES
PLUS
PROPERTIES PLUS setup run
Property
Analysis
Property
Estimation
Use Assay Data Analysis to analyze assay data when you do not want to perform a flowsheet
simulation in the same run.
Use Data Regression to fit physical property model parameters required by ASPEN PLUS to
measured pure component, VLE, LLE, and other mixture data. Data Regression can contain
property estimation and property analysis calculations. ASPEN PLUS cannot perform data
regression in a Flowsheet run.
Use PROPERTIES PLUS to prepare a property package for use with Aspen Custom Modeler
(formerly SPEEDUP) or Aspen Pinch (formerly ADVENT), with third-party commercial
engineering programs, or with your company's in-house programs. You must be licensed to use
PROPERTIES PLUS.
A standalone Property Analysis run
Use Property Analysis to generate property tables, PT-envelopes, residue curve maps, and other
property reports when you do not want to perform a flowsheet simulation in the same run.
Property Analysis can contain property estimation and assay data analysis calculations.
Standalone Property Constant Estimation run
Use Property Estimation to estimate property parameters when you do not want to perform a
flowsheet simulation in the same run.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 40
©1998 AspenTech. All rights reserved.
Setup Units
• Units in Aspen Plus can be defined at 3 different levels:
1.
2.
3.
•
Global Level (“Input Data” & “Output Results” fields on
the Setup Specifications Global sheet)
Object level (“Units” field in the top of any input form
of an object such as a block or stream
Field Level
Users can create their own units sets using the Setup
Units Sets Object Manager. Units can be copied from an
existing set and then modified.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 41
©1998 AspenTech. All rights reserved.
Components
• Use the Components Specifications form to specify all the
components required for the simulation.
• If available, physical property parameters for each
component are retrieved from databanks.
• Pure component databanks contain parameters such as
molecular weight, critical properties, etc. The databank
search order is specified on the Databanks sheet.
• The Find button can be used to search for components.
• The Electrolyte Wizard can be used to set up an
electrolyte simulation.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 42
©1998 AspenTech. All rights reserved.
Components Specifications Form
Septiembre 12, 2001
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Introduction to Aspen Plus
Slide 43
©1998 AspenTech. All rights reserved.
Entering Components
• The Component ID is used to identify the component in
simulation inputs and results.
• Each Component ID can be associated with a databank
component as either:
- Formula: Chemical formula of component (e.g., C6H6)
(Note that a suffix is added to formulas when there are
isomers, e.g. C2H6O-2)
- Component Name: Full name of component (e.g.,
BENZENE)
• Databank components can be searched for using the Find
button.
- Search using component name, formula, component
class, molecular weight, boiling point, or CAS number.
- All components containing specified items will be listed.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 44
©1998 AspenTech. All rights reserved.
Find
•
Find performs an AND search when more than one
criterion is specified.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 45
©1998 AspenTech. All rights reserved.
Pure Component Databanks
Databank Contents
Use
PURE10
Data from the Design Institute for Physical
Property Data (DIPPR) and AspenTech
Primary component databank in
Aspen Plus
AQUEOUS
Pure component parameters for ionic and
molecular species in aqueous solution
Simulations containing
electrolytes
SOLIDS
Pure component parameters for strong
electrolytes, salts, and other solids
Simulations containing
electrolytes and solids
INORGANIC Thermochemical properties for inorganic
components in vapor, liquid and solid states
Solids, electrolytes, and
metallurgy applications
PURE93
Data from the Design Institute for Physical
Property Data (DIPPR) and AspenTech
delivered with Aspen Plus 9.3
For upward compatibility
PURE856
Data from the Design Institute for Physical
Property Data (DIPPR) and AspenTech
delivered with Aspen Plus 8.5-6
For upward compatibility
ASPENPCD
Databank delivered with Aspen Plus 8.5-6
For upward compatibility
Parameters missing from the first selected databank will be searched for
in subsequent selected databanks.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 46
©1998 AspenTech. All rights reserved.
Properties
• Use the Properties Specifications form to specify the
physical property methods to be used in the simulation.
• Property methods are a collection of models and methods
used to describe pure component and mixture behavior.
• Choosing the right physical properties is critical for
obtaining reliable simulation results.
• Selecting a Process Type will narrow the number of
methods available.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 47
©1998 AspenTech. All rights reserved.
Properties Specifications Form
Septiembre 12, 2001
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Introduction to Aspen Plus
Slide 48
©1998 AspenTech. All rights reserved.
Streams
• Use Stream Input forms to specify the feed stream
conditions and composition.
• To specify stream conditions enter two of the following:
- Temperature
- Pressure
- Vapor Fraction
• To specify stream composition enter either:
- Total stream flow and component fractions
- Individual component flows
• Specifications for streams that are not feeds to the
flowsheet are used as estimates.
Septiembre 12, 2001
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Introduction to Aspen Plus
Slide 49
©1998 AspenTech. All rights reserved.
Streams Input Form
Septiembre 12, 2001
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Introduction to Aspen Plus
Slide 50
©1998 AspenTech. All rights reserved.
Blocks
• Each Block Input or Block Setup form specifies
operating conditions and equipment specifications for
the unit operation model.
• Some unit operation models require additional
specification forms
• All unit operation models have optional information
forms (e.g. BlockOptions form).
Septiembre 12, 2001
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Introduction to Aspen Plus
Slide 51
©1998 AspenTech. All rights reserved.
Block Form
Septiembre 12, 2001
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Introduction to Aspen Plus
Slide 52
©1998 AspenTech. All rights reserved.
Starting the Run
• Select Control Panel from the View menu or press the Next
button to be prompted.
- The simulation can be executed when all required forms
are complete.
- The Next button will take you to any incomplete forms.
Septiembre 12, 2001
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Introduction to Aspen Plus
Slide 53
©1998 AspenTech. All rights reserved.
Control Panel
The Control Panel consists of:
- A message window showing the progress of the
simulation by displaying the most recent messages
from the calculations
- A status area showing the hierarchy and order of
simulation blocks and convergence loops executed
- A toolbar which you can use to control the simulation
Run
Start or continue calculations
Step
Step through the flowsheet one
block at a time
Stop
Pause simulation calculations
Reinitialize
Purge simulation results
Results
Check simulation results
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 54
©1998 AspenTech. All rights reserved.
Reviewing Results
• History file or Control Panel Messages
- Contains any generated errors or warnings
- Select History or Control Panel on the View menu to
display the History file or the Control Panel
• Stream Results
- Contains stream conditions and compositions
• For all streams (/Data/Results Summary/Streams)
• For individual streams (bring up the stream folder in
the Data Browser and select the Results form)
• Block Results
- Contains calculated block operating conditions (bring
up the block folder in the Data Browser and select
the Results form)
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 55
©1998 AspenTech. All rights reserved.
Benzene Flowsheet Conditions Workshop
Objective: Add the process and feed stream conditions to a
flowsheet.
-
Starting with the flowsheet created in the Benzene Flowsheet
Definition Workshop (saved as BENZENE.BKP), add the process
and feed stream conditions as shown on the next page.
Questions: 1. What is the heat duty of the block “COOL”? _________
2. What is the temperature in the second flash
block “FL2”?
_________
Note:
Answers for all of the workshops are located in the very
back of the course notes in Appendix C.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 56
©1998 AspenTech. All rights reserved.
Benzene Flowsheet Conditions Workshop
VAP1
COOL
FL1
FEED
Feed
T = 1000 F
P = 550 psia
COOL
VAP2
T = 100 F
P = 500 psia
T = 200 F
FL2
Pdrop = 0
LIQ1
P = 1 atm
Q=0
Hydrogen: 405 lbmol/hr
Methane: 95 lbmol/hr
Benzene: 95 lbmol/hr
LIQ2
Toluene: 5 lbmol/hr
Use the PENG-ROB Property Method
Septiembre 12, 2001
®
Introduction to Aspen Plus
When finished, save as
filename: BENZENE.BKP
Slide 57
©1998 AspenTech. All rights reserved.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 58
©1998 AspenTech. All rights reserved.
Reach Your
True
Potential
Unit Operation Models
Objective:
Review major types of unit operation models
Aspen Plus References:
• User Guide, Chapter 10, Unit Operation Models
• Unit Operation Models Reference Manual
Introduction to Aspen Plus
®
59
©1998 AspenTech. All rights reserved.
Unit Operation Model Types
• Mixers/Splitters
• Separators
• Heat Exchangers
• Columns
• Reactors
• Pressure Changers
• Manipulators
• Solids
• User Models
Reference: The use of specific models is best described by on-line
help and the documentation.
• Aspen Plus Unit Operation Models Reference Manual
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 60
©1998 AspenTech. All rights reserved.
Mixers/Splitters
Model
Description
Purpose
Use
Mixer
Stream mixer
Combine multiple
streams into one
stream
Mixing tees, stream mixing
operations, adding heat
streams, adding work streams
FSplit
Stream splitter
Split stream flows
Stream splitters, bleed valves
SSplit
Substream splitter
Split substream flows
Solid stream splitters, bleed
valves
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 61
©1998 AspenTech. All rights reserved.
Separators
Model
Description Purpose
Use
Flash2
Two-outlet flash Determine thermal
and phase conditions
Flashes, evaporators, knockout
drums, single stage separators
Flash3
Three-outlet
flash
Determine thermal
and phase conditions
Decanters, single stage separators
with two liquid phases
Decanter
Liquid-liquid
decanter
Determine thermal
and phase conditions
Decanters, single stage separators
with two liquid phases and no vapor
phase
Sep
Multi-outlet
component
separator
Separate inlet stream
components into any
number of outlet
streams
Component separation operations
such as distillation and absorption,
when the details of the separation are
unknown or unimportant
Sep2
Two-outlet
component
separator
Separate inlet stream
components into two
outlet streams
Component separation operations
such as distillation and absorption,
when the details of the separation are
unknown or unimportant
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 62
©1998 AspenTech. All rights reserved.
Heat Exchangers
Model
Description Purpose
Use
Heater
Heater or cooler Determines thermal
and phase conditions
Heaters, coolers, valves. Pumps and
compressors when work-related
results are not needed.
HeatX
Two-stream
heat exchanger
Exchange heat
between two streams
Two-stream heat exchangers. Rating
shell and tube heat exchangers
when geometry is known.
MHeatX
Multistream
heat exchanger
Exchange heat
between any number
of streams
Multiple hot and cold stream heat
exchangers. Two-stream heat
exchangers. LNG exchangers.
Hetran*
Interface to
B-JAC Hetran
program
Design and simulate
shell and tube heat
exchangers
Shell and tube heat exchangers with
a wide variety of configurations.
Aerotran*
Interface to
B-JAC Aerotran
program
Design and simulate
air-cooled heat
exchangers
Air-cooled heat exchangers with a
wide variety of configurations. Model
economizers and the convection
section of fired heaters.
*
Requires separate license
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 63
©1998 AspenTech. All rights reserved.
Columns - Shortcut
Model
Description
DSTWU
Shortcut distillation Determine minimum RR,
Columns with one feed and
design
minimum stages, and either two product streams
actual RR or actual stages
by Winn-UnderwoodGilliland method.
Distl
Shortcut distillation Determine separation
rating
based on RR, stages, and
D:F ratio using Edmister
method.
Columns with one feed and
two product streams
SCFrac
Shortcut distillation Determine product
for petroleum
composition and flow,
fractionation
stages per section, duty
using fractionation indices.
Complex columns, such as
crude units and vacuum
towers
Septiembre 12, 2001
®
Purpose
Introduction to Aspen Plus
Use
Slide 64
©1998 AspenTech. All rights reserved.
Columns - Rigorous
Model
Description Purpose
Use
RadFrac
Rigorous
fractionation
Rigorous rating and design for single Distillation, absorbers, strippers,
columns
extractive and azeotropic distillation,
reactive distillation
MultiFrac
Rigorous
fractionation for
complex columns
Rigorous rating and design for
multiple columns of any complexity
Heat integrated columns, air separators,
absorber/stripper combinations, ethylene
primary fractionator/quench tower
combinations, petroleum refining
PetroFrac
Petroleum refining
fractionation
Rigorous rating and design for
petroleum refining applications
Preflash tower, atmospheric crude unit,
vacuum unit, catalytic cracker or coker
fractionator, vacuum lube fractionator,
ethylene fractionator and quench towers
BatchFrac*+
Rigorous batch
distillation
Rigorous rating calculations for
single batch columns
Ordinary azeotropic batch distillation,
3-phase, and reactive batch distillation
RateFrac*
Rate-based
distillation
Rigorous rating and design for single Distillation columns, absorbers, strippers,
and multiple columns. Based on
reactive systems, heat integrated units,
nonequilibrium calculations
petroleum applications
Extract
Liquid-liquid
extraction
Rigorous rating for liquid-liquid
extraction columns
Liquid-liquid extraction
*
Requires separate license
+ Input language only in Version 10.0
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 65
©1998 AspenTech. All rights reserved.
Reactors
Model
Description
Purpose
Use
RStoic
Stoichiometric
reactor
Stoichiometric reactor with
specified reaction extent or
conversion
Reactors where the kinetics are unknown or
unimportant but stoichiometry and extent are
known
RYield
Yield reactor
Reactor with specified yield Reactors where the stoichiometry and kinetics
are unknown or unimportant but yield
distribution is known
REquil
Equilibrium reactor
Chemical and phase
equilibrium by
stoichiometric calculations
Single- and two-phase chemical equilibrium
and simultaneous phase equilibrium
RGibbs
Equilibrium reactor
Chemical and phase
equilibrium by Gibbs
energy minimization
Chemical and/or simultaneous phase and
chemical equilibrium. Includes solid phase
equilibrium.
RCSTR
Continuous stirred
tank reactor
Continuous stirred tank
reactor
One, two, or three-phase stirred tank reactors
with kinetics reactions in the vapor or liquid
RPlug
Plug flow reactor
Plug flow reactor
One, two, or three-phase plug flow reactors with
kinetic reactions in any phase. Plug flow
reactions with external coolant.
RBatch
Batch reactor
Batch or semi-batch
reactor
Batch and semi-batch reactors where the
reaction kinetics are known
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 66
©1998 AspenTech. All rights reserved.
Pressure Changers
Model Description Purpose
Use
Pump
Pump or
hydraulic
turbine
Change stream pressure when
the pressure, power requirement
or performance curve is known
Pumps and hydraulic turbines
Compr
Compressor or
turbine
Change stream pressure when
the pressure, power requirement
or performance curve is known
Polytropic compressors, polytropic
positive displacement
compressors, isentropic
compressors, isentropic turbines.
MCompr Multi-stage
compressor or
turbine
Change stream pressure across
multiple stages with intercoolers.
Allows for liquid knockout
streams from intercoolers
Multistage polytropic compressors,
polytropic positive compressors,
isentropic compressors, isentropic
turbines.
Valve
Control valve
Determine pressure drop or
valve coefficient (CV)
Multi-phase, adiabatic flow in ball,
globe and butterfly valves
Pipe
Single-segment
pipe
Determine pressure drop and
heat transfer in single-segment
pipe or annular space
Multi-phase, one dimensional,
steady-state and fully developed
pipeline flow with fittings
Pipeline
Multi-segment
pipe
Determine pressure drop and
heat transfer in multi-segment
pipe or annular space
Multi-phase, one dimensional,
steady-state and fully developed
pipeline flow
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 67
©1998 AspenTech. All rights reserved.
Manipulators
Model
Description
Mult
Stream multiplier Multiply stream flows by
a user supplied factor
Multiply streams for scale-up or
scale-down
Dupl
Stream
duplicator
Copy a stream to any
number of outlets
Duplicate streams to look at
different scenarios in the same
flowsheet
ClChng
Stream class
changer
Change stream class
Link sections or blocks that use
different stream classes
Septiembre 12, 2001
®
Purpose
Introduction to Aspen Plus
Use
Slide 68
©1998 AspenTech. All rights reserved.
Solids
Model
Description
Uses
Crystallizer
Continuous Crystallizer
Mixed suspension, mixed product removal (MSMPR)
crystallizeer used for the production of a single solid product
Crusher
Crushers
Gyratory/jaw crusher, cage mill breaker, and single or
multiple roll crushers
Screen
Screens
Solids-solids separation using screens
FabFl
Fabric filters
Gas-solids separation using fabric filters
Cyclone
Cyclones
Gas-solids separation using cyclones
VScrub
Venturi scrubbers
Gas-solids separation using venturi scrubbers
ESP
Dry electrostatic precipitators
Gas-solids separation using dry electrostatic precipitators
HyCyc
Hydrocyclones
Liquid-solids separation using hydrocyclones
CFuge
Centrifuge filters
Liquid-solids separation using centrifuge filters
Filter
Rotary vacuum filters
Liquid-solids separation using continuous rotary vacuum
filters
SWash
Single-stage solids washer
Single-stage solids washer
CCD
Counter-current decanter
Multistage washer or a counter-current decanter
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 69
©1998 AspenTech. All rights reserved.
User Models
•
Proprietary models or 3-rd party software can be
included in an Aspen Plus flowsheet using a User2 unit
operation block.
•
Excel Workbooks or Fortran code can be used to define
the User2 unit operation model.
•
•
User-defined names can be associated with variables.
•
Aspen Plus helper functions eliminate the need to know
the internal data structure to retrieve variables.
Variables can be dimensioned based on other input
specifications (for example, number of components).
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 70
©1998 AspenTech. All rights reserved.
Subflowsheets
•
Existing simulations (*.bkp or *.apw files) can be used
as part of a new flowsheet
•
Select “Subflowsheet” from the User Model tab of the
Model Library to create a subflowsheet in the main
flowsheet.
•
Inlet and outlet streams must have the same name in
the subflowsheet and in the main flowsheet.
•
•
Components must be identical in all flowsheets.
Each ID (block, stream, design-spec, etc.) must be
unique.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 71
©1998 AspenTech. All rights reserved.
Model Templating
•
Custom model libraries containing categorized groups
of models can be displayed with the Aspen Plus Model
Library.
•
Any Aspen Plus model on the flowsheet can be added
to the custom model library. Any data entered for the
block will be associated with that model.
•
Custom icons to better represent the equipment can be
created for any model in a custom model library.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 72
©1998 AspenTech. All rights reserved.
Model Templating (Continued)
1. Create a custom model library, by selecting New from
the Library menu. Enter the name of the library and the
location of the library file.
2. Edit the library by selecting the library name and Edit
from the Library menu.
3. Create categories by selecting New from the Category
menu.
4. Add models to the library by selecting a block on the
flowsheet, clicking the right mouse button, and
selecting “Add to model library” from the list.
5. Select Save from the Library menu to save the library.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 73
©1998 AspenTech. All rights reserved.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 74
©1998 AspenTech. All rights reserved.
Reach Your
True
Potential
RadFrac
Objective:
Discuss the minimum input required for the RadFrac
fractionation model, and the use of design specifications
and stage efficiencies
Aspen Plus References:
• Unit Operation Models Reference Manual, Chapter 4, Columns
Introduction to Aspen Plus
®
75
©1998 AspenTech. All rights reserved.
RadFrac: Rigorous Multistage Separation
• Vapor-Liquid or Vapor-Liquid-Liquid phase simulation of:
- Ordinary distillation
- Absorption, reboiled absorption
- Stripping, reboiled stripping
- Azeotropic distillation
- Reactive distillation
• Configuration options:
- Any number of feeds
- Any number of side draws
- Total liquid draw off and pumparounds
- Any number of heaters
- Any number of decanters
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 76
©1998 AspenTech. All rights reserved.
RadFrac Flowsheet Connectivity
Vapor Distillate
Top-Stage or
Condenser Heat Duty
1
Heat (optional)
Liquid Distillate
Water Distillate (optional)
Feeds
Reflux
Products (optional)
Heat (optional)
Pumparound
Decanters
Heat (optional)
Heat (optional)
Boil-up
Bottom Stage or
Reboiler Heat Duty
Product
Return
Nstage
Heat (optional)
Bottoms
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 77
©1998 AspenTech. All rights reserved.
RadFrac Setup Configuration Sheet
• Specify:
- Number of stages
- Condenser and reboiler configuration
- Two column operating specifications
- Valid phases
- Convergence
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 78
©1998 AspenTech. All rights reserved.
RadFrac Setup Streams Sheet
• Specify:
- Feed stage location
- Feed stream convention (see Help)
ABOVE-STAGE:
Vapor from feed goes to stage above feed stage
Liquid goes to feed stage
ON-STAGE:
Vapor & Liquid from feed go to specified feed stage
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 79
©1998 AspenTech. All rights reserved.
Feed Convention
Above-stage
(default)
n-1
On-stage
n-1
Vapor
Feed
Liquid
n
Feed
n
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 80
©1998 AspenTech. All rights reserved.
RadFrac Setup Pressure Sheet
• Specify one of:
- Column pressure profile
- Top/Bottom pressure
- Section pressure drop
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 81
©1998 AspenTech. All rights reserved.
Methanol-Water RadFrac Column
OVHD
FEED
RadFrac specifications
Total Condenser
COLUMN
T = 65 C
P = 1 bar
BTMS
Water: 100 kmol/hr
Methanol: 100 kmol/hr
Use the NRTL-RK Property Method
Septiembre 12, 2001
®
Introduction to Aspen Plus
Kettle Reboiler
9 Stages
Reflux Ratio = 1
Distillate to feed ratio = 0.5
Column pressure = 1 bar
Feed stage = 6
Filename: RAD-EX.BKP
Slide 82
©1998 AspenTech. All rights reserved.
RadFrac Options
• To set up an absorber with no condenser or reboiler, set
condenser and reboiler to none on the RadFrac Setup
Configuration sheet.
• Either Vaporization or Murphree efficiencies on either a
stage or component basis can be specified on the
RadFrac Efficiencies form.
• Tray and packed column design and rating is possible.
• A Second liquid phase may be modeled if the user selects
Vapor-liquid-liquid as Valid phases.
• Reboiler and condenser heat curves can be generated.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 83
©1998 AspenTech. All rights reserved.
Plot Wizard
•
Use Plot Wizard (on the Plot menu) to quickly generate
plots of results of a simulation. You can use Plot Wizard
for displaying results for the following operations:
-
Physical property analysis
Data regression analysis
Profiles for all separation models RadFrac, MultiFrac,
PetroFrac and RateFrac
•
Click the object of interest in the Data Browser to
generate plots for that particular object.
•
The wizard guides you in the basic operations for
generating a plot.
•
Click on the Next button to continue. Click on the
Finish button to generate a plot with default settings.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 84
©1998 AspenTech. All rights reserved.
Plot Wizard Demonstration
Use the plot wizard on the column to create a plot of
the vapor phase compositions throughout the column.
Block COLUMN: Vapor Composition Profiles
WATER
METHANOL
Y (mole frac)
0.25
0.5
0.75
1
•
1
Septiembre 12, 2001
®
2
3
4
5
Stage
6
7
Introduction to Aspen Plus
8
9
Slide 85
©1998 AspenTech. All rights reserved.
RadFrac DesignSpecs and Vary
• Design specifications can be specified and executed
inside the RadFrac block using the DesignSpecs and
Vary forms.
• One or more RadFrac inputs can be manipulated to
achieve specifications on one or more RadFrac
performance parameters.
• The number of specs should, in general, be equal to the
number of varies.
• The DesignSpecs and Varys in a RadFrac are solved in a
“Middle loop.” If you get an error message saying that the
middle loop was not converged, check the DesignSpecs
and Varys you have entered.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 86
©1998 AspenTech. All rights reserved.
RadFrac Convergence Problems
If a RadFrac column fails to converge, doing one or more of
the following could help:
1. Check that physical property issues (choice of
Property Method, parameter availability, etc.) are
properly addressed.
2. Ensure that column operating conditions are feasible.
3. If the column err/tol is decreasing fairly consistently,
increase the maximum iterations on the RadFrac
Convergence Basic sheet.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 87
©1998 AspenTech. All rights reserved.
RadFrac Convergence Problems (Continued)
4. Provide temperature estimates for some stages in
the column using the RadFrac Estimates
Temperature sheet (useful for absorbers).
5. Provide composition estimates for some stages in
the column using the RadFrac Estimates Liquid
Composition and Vapor Composition sheet (useful
for highly non-ideal systems).
6. Experiment with different convergence methods on
the RadFrac Setup Configuration sheet.
>> When a column does not converge, it is usually
beneficial to Reinitialize after making changes.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 88
©1998 AspenTech. All rights reserved.
RadFrac Workshop
Part A:
•
Perform a rating calculation of a Methanol tower using the following
data:
DIST
FEED
COLUMN
Feed:
63.2 wt% Water
36.8 wt% Methanol
Total flow = 120,000 lb/hr
Pressure 18 psia
Saturated liquid
Column specification:
38 trays (40 stages)
Feed tray = 23 (stage 24)
Total condenser
Top stage pressure = 16.1 psia
Pressure drop per stage = 0.1 psi
Distillate flowrate = 1245 lbmol/hr
Molar reflux ratio = 1.3
BTMS
Use the NRTL-RK Property Method
Septiembre 12, 2001
®
Introduction to Aspen Plus
Filename: RADFRAC.BKP
Slide 89
©1998 AspenTech. All rights reserved.
RadFrac Workshop (Continued)
Part B:
•
Set up design specifications within the column so the following two
objectives are met:
•
99.95 wt% methanol in the distillate
99.90 wt% water in the bottoms
To achieve these specifications, you can vary the distillate rate (8001700 lbmol/hr) and the reflux ratio (0.8-2). Make sure stream
compositions are reported as mass fractions before running the
problem. Note the condenser and reboiler duties:
Condenser Duty :_________
Reboiler Duty :_________
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 90
©1998 AspenTech. All rights reserved.
RadFrac Workshop (Continued)
Part C:
•
Perform the same design calculation after specifying a 65% Murphree
efficiency for each tray. Assume the condenser and reboiler have
stage efficiencies of 90%.
•
How do these efficiencies affect the condenser and reboiler duties of
the column?
Part D:
•
Perform a tray sizing calculation for the entire column, given that
Bubble Cap trays are used.
(When finished, save as filename: RADFRAC.BKP)
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 91
©1998 AspenTech. All rights reserved.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 92
©1998 AspenTech. All rights reserved.
Reach Your
True
Potential
Reactor Models
Objective:
Introduce the various classes of reactor models
available, and examine in some detail at least one
reactor from each class
Aspen Plus References:
• Unit Operation Models Reference Manual, Chapter 5, Reactors
Introduction to Aspen Plus
®
93
©1998 AspenTech. All rights reserved.
Reactor Overview
Reactors
Balance Based
RYield
RStoic
Septiembre 12, 2001
®
Equilibrium Based
REquil
RGibbs
Introduction to Aspen Plus
Kinetics Based
RCSTR
RPlug
RBatch
Slide 94
©1998 AspenTech. All rights reserved.
Balanced Based Reactors
• RYield
- Requires a mass balance only, not an atom balance
- Is used to simulate reactors in which inlets to the
reactor are not completely known but outlets are
known (e.g. to simulate a furnace)
RYield
1000 lb/hr Coal
70 lb/hr H2 O
20 lb/hr CO 2
60 lb/hr CO
250 lb/hr tar
600 lb/hr char
IN
OUT
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 95
©1998 AspenTech. All rights reserved.
Balanced Based Reactors (Continued)
• RStoic
- Requires both an atom and a mass balance
- Used in situations where both the equilibrium data and
-
the kinetics are either unknown or unimportant
Can specify or calculate heat of reaction at a reference
temperature and pressure
RStoic
C, O2
IN
2 CO + O2 --> 2 CO2
C + O2 --> CO2
2 C + O2 --> 2 CO
C, O2, CO, CO2
OUT
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 96
©1998 AspenTech. All rights reserved.
Equilibrium Based Reactors
• GENERAL
- Do not take reaction kinetics into account
- Solve similar problems, but problem specifications are
-
different
Individual reactions can be at a restricted equilibrium
• REquil
- Computes combined chemical and phase equilibrium
by solving reaction equilibrium equations
- Cannot do a 3-phase flash
- Useful when there are many components, a few known
reactions, and when relatively few components take
part in the reactions
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 97
©1998 AspenTech. All rights reserved.
Equilibrium Based Reactors (Continued)
• RGibbs
- Unknown Reactions
-
This feature is quite useful when reactions occurring
are not known or are high in number due to many
components participating in the reactions.
Gibbs Energy Minimization
A Gibbs free energy minimization is done to determine
the product composition at which the Gibbs free
energy of the products is at a minimum.
Solid Equilibrium
RGibbs is the only Aspen Plus block that will deal with
solid-liquid-gas phase equilibrium.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 98
©1998 AspenTech. All rights reserved.
Kinetic Reactors
• Kinetic reactors are RCSTR, RPlug and RBatch.
• Reaction kinetics are taken into account, and hence must
be specified.
• Kinetics can be specified using one of the built-in models,
or with a user subroutine. The current built-in models are
- Power Law
- Langmuir-Hinshelwood-Hougen-Watson (LHHW)
• A catalyst for a reaction can have a reaction coefficient of
zero.
• Reactions are specified using a Reaction ID.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 99
©1998 AspenTech. All rights reserved.
Using a Reaction ID
• Reaction IDs are setup as objects, separate from the
reactor, and then referenced within the reactor(s).
• A single Reaction ID can be referenced in any number of
kinetic reactors (RCSTR, RPlug and RBatch.)
• To set up a Reaction ID, go to the Reactions Reactions
Object Manager
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 100
©1998 AspenTech. All rights reserved.
Power-law Rate Expression
rate = k * ∏ [ c o n c e n t r a ti o n i ]exponent i
i
 Activation Energy  1 1  
T 
k = (Pre − exponentia l Factor)   exp  −
 −  
R
 T0 
 T T0  

n
→ C + 2 D
2 A + 3B ←

k 2
k1
Example:
Forward reaction: (Assuming the reaction is 2nd order in A)
coefficients:
A: -2 B: -3 C: 1
D: 2
exponents:
A: 2 B: 0 C: 0
D: 0
Reverse reaction: (Assuming the reaction is 1st order in C and D)
coefficients:
C: -1 D: -2
A: 2 B: 3
exponents:
C: 1 D: 1
A: 0 B: 0
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 101
©1998 AspenTech. All rights reserved.
Heats of Reaction
• Heats of reaction need not be provided for reactions.
• Heats of reaction are typically calculated as the difference
between inlet and outlet enthalpies for the reactor (see
Appendix A).
• If you have a heat of reaction value that does not match
the value calculated by Aspen Plus, you can adjust the
heats of formation (DHFORM) of one or more
components to make the heats of reaction match.
• Heats of reaction can also be calculated or specified at a
reference temperature and pressure in an RStoic reactor.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 102
©1998 AspenTech. All rights reserved.
Reactor Workshop
Objective: Compare the use of different reactor types to
model one reaction.
Reactor Conditions:
Temperature = 70 C
Pressure = 1 atm
Stoichiometry:
Ethanol + Acetic Acid < --> Ethyl Acetate + Water
Kinetic Parameters:
Forward Reaction: Pre-exp. Factor = 1.9 x 108, Act. Energy = 5.95 x 10 7 J/kmol
Reverse Reaction: Pre-exp. Factor = 5.0 x 107,Act. Energy = 5.95 x 107 J/kmol
Reactions are first order with respect to each of the reactants in the reaction (second
order overall).
Reactions occur in the liquid phase.
Composition basis is Molarity.
Hint: Check that each reactor is considering both Vapor and Liquid as Valid phases.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 103
©1998 AspenTech. All rights reserved.
Reactor Workshop (Continued)
Use the NRTL-RK property method
P-STOIC
RSTOIC
F-STOIC
70 % conversion of ethanol
F-GIBBS
FEED
Feed:
Temp = 70 C
DUPL
Pres = 1 atm
Water: 8.892 kmol/hr
Ethanol: 186.59 kmol/hr
Acetic Acid: 192.6 kmol/hr
P-GIBBS
RGIBBS
F-PLUG
P-PLUG
RPLUG
F-CSTR
Length = 2 meters
Diameter = 0.3 meters
P-CSTR
When finished, save as
filename: REACTORS.BKP
Septiembre 12, 2001
®
RCSTR
Introduction to Aspen Plus
Volume = 0.14 Cu. M.
Slide 104
©1998 AspenTech. All rights reserved.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 105
©1998 AspenTech. All rights reserved.
Reach Your
True
Potential
Cyclohexane Production Workshop
Introduction to Aspen Plus
®
106
©1998 AspenTech. All rights reserved.
Cyclohexane Production Workshop
Objective: Create a flowsheet to model a cyclohexane
production process
Cyclohexane can be produced by the hydrogenation of benzene in the
following reaction:
C6H 6
Benzene
+
3 H2
Hydrogen
=
C6 H12
Cyclohexane
The benzene and hydrogen feeds are combined with recycle hydrogen
and cyclohexane before entering a fixed bed catalytic reactor. Assume
a benzene conversion of 99.8%.
The reactor effluent is cooled and the light gases separated from the
product stream. Part of the light gas stream is fed back to the reactor as
recycle hydrogen.
The liquid product stream from the separator is fed to a distillation
column to further remove any dissolved light gases and to stabilize the
end product. A portion of the cyclohexane product is recycled to the
reactor to aid in temperature control.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 107
©1998 AspenTech. All rights reserved.
Cyclohexane Production Workshop
C6 H6
+ 3 H2
=
C 6H12
Benzene
Hydrogen
Cyclohexane
PURGE
Total flow = 330 kmol/hr
T = 50 C
P = 25 bar
Molefrac H2 = 0.975
N2 = 0.005
CH4 = 0.02
H2IN
92% flow to stream H2RCY
VFLOW
H2RCY
VAP
FEED-MIX
REACT
RXIN
BZIN
T = 150C
P = 23 bar
T = 40 C
P = 1 bar
Benzene flow = 100 kmol/hr
HP-SEP
T = 200 C
Pdrop = 1 bar
Benzene conv =
0.998
LTENDS
T = 50 C
Pdrop = 0.5 bar
RXOUT
Theoretical Stages = 12
Reflux ratio = 1.2
Bottoms rate = 99 kmol/hr
Partial Condenser with
vapor distillate only
Column Pressure = 15 bar
Feed stage = 8
LIQ
CHRCY
COLFD
LFLOW
30% flow to stream CHRCY
Use the RK-SOAVE property method
®
COLUMN
Specify cyclohexane mole
recovery of 0.9999 by varying
Bottoms rate from 97 to 101 kmol/hr
When finished, save as
filename: CYCLOHEX.BKP
Septiembre 12, 2001
PRODUCT
Introduction to Aspen Plus
Slide 108
©1998 AspenTech. All rights reserved.
Reach Your
True
Potential
Physical Properties
Objectives:
Introduce the ideas of property methods and physical
property parameters
Identify issues involved in the choice of a property method
Cover the use of Property Analysis for reporting physical
properties
Aspen Plus References:
• User Guide, Chapter 7, Physical Property Methods
• User Guide, Chapter 8, Physical Property Parameters and Data
• User Guide, Chapter 29,Introduction
Analyzing
Properties
to Aspen
Plus
109
®
©1998 AspenTech. All rights reserved.
Case Study - Acetone Recovery
• Correct choice of physical property models and accurate
physical property parameters are essential for obtaining
accurate simulation results.
OVHD
COLUMN
FEED
5000 lbmol/hr
10 mole % acetone
90 mole % water
BTMS
Specification: 99.5 mole % acetone recovery
Ideal
Approach
Equation of
State Approach
Activity Coefficient
Model Approach
Predicted number of stages
required
11
7
42
Approximate cost in dollars
520,000
390,000
880,000
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 110
©1998 AspenTech. All rights reserved.
How to Establish Physical Properties
Choose a Property Method
Check Parameters/Obtain
Additional Parameters
Confirm Results
Create the Flowsheet
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 111
©1998 AspenTech. All rights reserved.
Property Methods
• A Property Method is a collection of models and methods
used to calculate physical properties.
• Property Methods containing commonly used
thermodynamic models are provided in Aspen Plus.
• Users can modify existing Property Methods or create
new ones.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 112
©1998 AspenTech. All rights reserved.
Physical Property Models
Approaches to representing physical properties of
components
Physical Property Models
Ideal
Equation of State
(EOS)
Models
Activity
Coefficient
Models
Special
Models
• Choice of model types depends on degree of non-ideal
behavior and operating conditions.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 113
©1998 AspenTech. All rights reserved.
Ideal vs. Non-Ideal Behavior
• What do we mean by ideal behavior?
y
- Ideal Gas law and Raoult’s law
x
• Which systems behave as ideal?
- Non-polar components of similar size and shape
• What controls degree of non-ideality?
- Molecular interactions
e.g. Polarity, size and shape of the molecules
• How can we study the degree of non-ideality of a system?
- Property plots (e.g. TXY & XY)
y
y
x
Septiembre 12, 2001
®
Introduction to Aspen Plus
x
Slide 114
©1998 AspenTech. All rights reserved.
Comparison of EOS and Activity Models
EOS Models
Activity Coefficient Models
Limited in ability to represent
non-ideal liquids
Can represent highly non-ideal liquids
Fewer binary parameters
required
Many binary parameters required
Parameters extrapolate
reasonably with temperature
Binary parameters are highly
temperature dependent
Consistent in critical region
Inconsistent in critical region
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 115
©1998 AspenTech. All rights reserved.
Common Property Methods
• Equation of State Property Methods
- PENG-ROB
- RK-SOAVE
• Activity Coefficient Property Methods
- NRTL
- UNIFAC
- UNIQUAC
- WILSON
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 116
©1998 AspenTech. All rights reserved.
Henry's Law
• Henry's Law is only used with ideal and activity coefficient
models.
• It is used to determine the amount of a supercritical
component or light gas in the liquid phase.
• Any supercritical components or light gases (CO2, N2,
etc.) should be declared as Henry's components
(Components Henry Comps Selection sheet).
• The Henry's components list ID should be entered on
Properties Specifications Global sheet in the Henry
Components field.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 117
©1998 AspenTech. All rights reserved.
Choosing a Property Method - Review
Do you have any
polar components
in your system?
N
Use EOS Model
Y
Y
Are the operating conditions
near the critical region of the
mixture?
N
Do you have light gases or
supercritical components
in your system?
Reference: Aspen Plus User
Guide, Chapter 7, Physical
Property Methods, gives
similar, more detailed
guidelines for choosing a
Property Method.
Septiembre 12, 2001
®
Y
Use activity
coefficient model
with Henry’s Law
Introduction to Aspen Plus
N
Use activity
coefficient
model
Slide 118
©1998 AspenTech. All rights reserved.
Choosing a Property Method - Example
System
Model Type
Property Method
Propane, Ethane, Butane
EOS
RK-SOAVE, PENG-ROB
Benzene, Water
Activity Coefficient
NRTL-RK, UNIQUAC
Acetone, Water
Activity Coefficient
NRTL-RK, WILSON
Choose an appropriate Property Method for the following
systems of components at ambient conditions.
System
Property Method
Ethanol, Water
Benzene, Toluene
Acetone, Water, Carbon Dioxide
Water, Cyclohexane
Ethane and Propanol
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 119
©1998 AspenTech. All rights reserved.
How to Establish Physical Properties
Choose a Property Method
Check Parameters/Obtain
Additional Parameters
Confirm Results
Create the Flowsheet
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 120
©1998 AspenTech. All rights reserved.
Pure Component Parameters
• Represent attributes of a single component
• Input in the Properties Parameters Pure Component
folder.
• Stored in databanks such as PURE10, ASPENPCD,
SOLIDS, etc. (The selected databanks are listed on the
Components Specifications Databanks sheet.)
• Parameters retrieved into the Graphical User Interface by
selecting Retrieve Parameter Results from the tools menu.
• Examples
- Scalar: MW for molecular weight
- Temperature-Dependent: PLXANT for parameters in
the extended Antoine vapor pressure model
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 121
©1998 AspenTech. All rights reserved.
Binary Parameters
• Used to describe interactions between two components
• Input in the Properties Parameters Binary Interaction
folder
• Stored in binary databanks such as VLE-IG, LLE-ASPEN
• Parameter values from the databanks can be viewed on
the input forms in the Graphical User Interface.
• Parameter forms that include data from the databanks
must be viewed before the flowsheet is complete.
• Examples
- Scalar: RKTKIJ for the Rackett model
- Temperature-Dependent: NRTL for parameters in the
NRTL model
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 122
©1998 AspenTech. All rights reserved.
Displaying Property Parameters
•
Aspen Plus does not display all databank parameters
on the parameter input forms.
•
Select Retrieve Parameter Results from the Tools
menu to retrieve all parameters for the components and
property methods defined in the simulation.
•
All results that are currently loaded will be lost. They
can be regenerated by running the simulation again.
•
The parameters are viewed on the Properties
Parameters Results forms.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 123
©1998 AspenTech. All rights reserved.
Reporting Physical Property Parameters
Follow this procedure to obtain a report file containing
values of ALL pure component and binary parameters for
ALL components used in a simulation:
1. On the Setup Report Options Property sheet,
select All physical property parameters used (in SI
units) or select Property parameters’ descriptions,
equations, and sources of data.
2. After running the simulation, export a report (*.rep)
file (Select Export from the File menu).
3. Edit the .rep file using any text editor. (From the
Graphical User Interface, you can choose Report
from the View menu.) The parameters are listed
under the heading PARAMETER VALUES in the
physical properties section of the report file.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 124
©1998 AspenTech. All rights reserved.
Parameter Reports
All physical property
parameters used
(in SI units)
Property parameters’
descriptions, equations,
and sources of data
Parameters are reported in SI
units, and the units of the
parameters are not printed.
Parameters are reported in
output-units, and the units of the
parameters are printed.
Only Aspen Plus abbreviations for Aspen Plus abbreviation along
the parameter names are printed. with a description is printed
Output is fairly compact.
Output is quite long.
Equations for temperaturedependent parameters are listed.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 125
©1998 AspenTech. All rights reserved.
How to Establish Physical Properties
Choose a Property Method
Check Parameters/Obtain
Additional Parameters
Confirm Results
Create the Flowsheet
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 126
©1998 AspenTech. All rights reserved.
Property Analysis
• Used to generate simple property diagrams to validate
physical property models and data
•
Diagram Types:
- Pure component, e.g. Vapor pressure vs. temperature
- Binary, e.g. TXY, PXY
- Ternary residue maps
•
•
Select Analysis from the Tools menu to start Analysis.
•
When using a binary analysis to check for liquid-liquid
phase separation, remember to choose Vapor-LiquidLiquid as Valid phases.
•
Property analysis input and results can be saved as a
form for later reference and use.
Additional binary plots are available under the Plot
Wizard button on result form containing raw data.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 127
©1998 AspenTech. All rights reserved.
Property Analysis - Common Plots
Ideal XY Plot:
XY Plot Showing Azeotrope:
0
0
0
0
0
0
0
0
1
y-x diagram for ETHANOL / TOLUENE
1
y-x diagram for METHANOL / PROPANOL
V
0
.
0.2
0.4
0.6
0.8
1
LIQUID MOLEFRAC METHANOL
0.2
0.4
0.6
0.8
1
LIQUID MOLEFRAC ETHANOL
XY Plot Showing 2 liquid phases:
.
.
.
0
(PRES = 14.7 PSI)
V
(PRES = 14.7 PSI)
.
1
0
8
6
4
(PRES = 14.7 PSI)
V
®
.
0.2
0.4
0.6
0.8
1
LIQUID MOLEFRAC TOLUENE
P
Introduction to Aspen Plus
.
Septiembre 12, 2001
A
.
2
0
2
P
4
0
6
0
8
0
A
.
.
A
.
y-x diagram for TOLUENE / WATER
Slide 128
©1998 AspenTech. All rights reserved.
Additional Data from DETHERM
• DETHERM databank is maintained by DECHEMA.
• DETHERM contains the world’s most comprehensive
single source of thermophysical properties.
- Phase equilibria data
- Azeotropic data
- Excess properties
- PVT data
- Caloric properties
- Transport properties
- Electrolyte data
• The interface can be launched from within Aspen Plus to
access data via the Internet or CD-ROM.
• Users are charged for each set of data that is downloaded.
• Data can be regressed using Aspen Plus Data Regression.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 129
©1998 AspenTech. All rights reserved.
Interface to DETHERM Example
1. Enter your components on the Components
Specifications Selection sheet.
2. Click on the DETHERM Interface button on the toolbar.
3. Click on the Search button in the DETHERM interface.
4. Select the data sets from the list of data.
5. Click on the Transfer button.
6. Enter your user ID information.
7. Receive the data into Aspen Plus.
- Scalar data is entered on Property Parameters forms.
- Temperature dependent and Binary data sets are
entered on the Properties Data forms.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 130
©1998 AspenTech. All rights reserved.
Interface to DETHERM Example
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 131
©1998 AspenTech. All rights reserved.
Interface to DETHERM Example
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 132
©1998 AspenTech. All rights reserved.
Interface to the DETHERM Databank
• For more information
- The AspenTech partnership with DECHEMA
- Download and usage of DETHERM Internet Client
- How to sign up for an account
http://www.aspentech.com/partner/.
Septiembre 12, 2001
®
(then click on DECHEMA)
Introduction to Aspen Plus
Slide 133
©1998 AspenTech. All rights reserved.
How to Establish Physical Properties
Choose a Property Method
Check Parameters/Obtain
Additional Parameters
Confirm Results
Create the Flowsheet
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 134
©1998 AspenTech. All rights reserved.
Establishing Physical Properties - Review
1. Choose Property Method - Select a Property Method based on
- Components present in simulation
- Operating conditions in simulation
- Available data or parameters for the components
2. Check Parameters - Determine parameters available in Aspen
Plus databanks
3. Obtain Additional Parameters (if necessary) - Parameters that
are needed can be obtained from
- Literature searches
- Regression of experimental data (Data Regression)
- Property Constant Estimation (Property Estimation)
4. Confirm Results - Verify choice of Property Method and
physical property data using
- Physical Property Analysis
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 135
©1998 AspenTech. All rights reserved.
Property Sets
• A property set (Prop-Set) is a way of accessing a
collection, or set, of properties as an object with a usergiven name. Only the name of the property set is
referenced when using the properties in an application.
• Use property sets to report thermodynamic, transport, and
other property values.
• Current property set applications include:
- Design specifications, Fortran blocks, sensitivity
- Stream reports
- Physical property tables (Property Analysis)
- Tray properties (RadFrac, MultiFrac, etc.)
- Heating/cooling curves (Flash2, MHeatX, etc.)
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 136
©1998 AspenTech. All rights reserved.
Properties included in Prop-Sets
• Properties commonly included in property sets include:
- VFRAC - Molar vapor fraction of a stream
- BETA - Fraction of liquid in a second liquid phase
- CPMX - Constant pressure heat capacity for a mixture
- MUMX - Viscosity for a mixture
• Available properties include:
- Thermodynamic properties of components in a mixture
- Pure component thermodynamic properties
- Transport properties
- Electrolyte properties
- Petroleum-related properties
Reference: Aspen Plus Physical Property Data Reference Manual,
Chapter 4, Property Sets, has a complete list of properties that can be
included in a property set.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 137
©1998 AspenTech. All rights reserved.
Specifying Property Sets
• Use the Properties Prop-Sets form to specify properties in
a property set.
• The Search button can be used to search for a property.
• All specified qualifiers apply to each property specified,
where applicable.
• Users can define new properties on the Properties
Advanced User-Properties form by providing a Fortran
subroutine.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 138
©1998 AspenTech. All rights reserved.
Predefined Property Sets
Some simulation Templates contain predefined property
sets.
The following table lists predefined property sets and the
types of properties they contain for the General Template:
Predefined Property Set
Types of Properties
HXDESIGN
Heat exchanger design
THERMAL
Mixture thermal (HMX, CPMX,
KMX)
TXPORT
Transport
VLE
Vapor-liquid equilibrium
(PHIMX, GAMMA, PL)
VLLE
Vapor-liquid-liquid equilibrium
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 139
©1998 AspenTech. All rights reserved.
Stream Results Options
• On the Setup Report Options Stream sheet, use:
- Flow Basis and Fraction Basis check-boxes to
specify how stream composition is reported
- Property Sets button to specify names of property
sets containing additional properties to be reported for
each stream
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 140
©1998 AspenTech. All rights reserved.
Definition of Terms
• Property Method - Set of property models and methods
used to calculate the properties required for a simulation
•
Property - Calculated physical property value such as
mixture enthalpy
•
Property Model - Equation or equations used to
calculate a physical property
•
•
Property Parameter - Constant used in a property model
Property Set (Prop-Set) - A method of accessing
properties so that they can be used or tabulated
elsewhere
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 141
©1998 AspenTech. All rights reserved.
Physical Properties Workshop
Objective: Simulate a two-liquid phase settling tank and
investigate the physical properties of the system.
A refinery has a settling tank that they use to decant off the water from a
mixture of water and a heavy oil. The inlet stream to the tank also
contains some carbon-dioxide and nitrogen. The tank and feed are at
ambient temperature and pressure (70o F, 1atm), and have the following
flow rates of the various components:
Water
Oil
CO2
N2
515 lb/hr
4322 lb/hr
751 lb/hr
43 lb/hr
Use the compound n-decane to represent the oil. It is known that water
and oil form two liquid phases under the conditions in the tank.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 142
©1998 AspenTech. All rights reserved.
Physical Properties Workshop (Continued)
1. Choose an appropriate Property Method to represent this system.
Check to see that the required binary physical property parameters
are available.
2. Using the property analysis feature, verify that the chosen physical
property model and the available parameters predict the formation
of 2 liquid phases.
3. Set up a simulation to model the settling tank. Use a Flash3 block
to represent the tank.
4. Modify the stream report to include the constant pressure heat
capacity (CPMX) for each phase (Vapor, 1st Liquid and 2nd Liquid),
and the fraction of liquid in a second liquid phase (BETA), for all
streams.
5. Retrieve the physical property parameters used in the simulation
and determine the critical temperature for carbon dioxide and water.
TC(carbon dioxide) = _______; TC(water) = _______
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 143
©1998 AspenTech. All rights reserved.
Physical Properties Workshop (Continued)
Optional Part:
Objective: Generate a table of compositions for each liquid
phase (1st Liquid and 2nd Liquid) at different temperatures
for a mixture of water and oil. Tabulate the vapor pressure of
the components in the same table.
•
In addition to the interactive Analysis commands under the Tools
menu, you also can create a Property Analysis manually, using forms.
•
Manually generated Properties Analyses are created using the
Properties Analysis Object Manager.
•
Manually created Property Analyses can be executed at the end of a
flowsheet simulation or as a stand-alone run using a Run-Type of
Property Analysis.
•
A manually generated Generic Property Analysis is similar to the
interactive Analysis commands, however it is more flexible regarding
input and reporting.
Detailed instructions are on the following slide.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 144
©1998 AspenTech. All rights reserved.
Physical Properties Workshop (Continued)
Problem Specifications:
1. Create a Generic type property analysis.
2. Generate points along a flash curve.
3. Define component flows of 50 mole water and 50 mole oil.
4. Set Valid phases to Vapor-liquid-liquid.
5. Vary the temperature from 50 to 400 F.
6. Use a vapor fraction of zero.
7. Tabulate a new property set that includes:
a. Mole fraction of water and oil in the 1st and 2nd liquid phases
b. Mole flow of water and oil in the 1st and 2nd liquid phases
c. Beta - the fraction of the 1st liquid to the total liquid
d. Pure component vapor pressures of water and oil
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 145
©1998 AspenTech. All rights reserved.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 146
©1998 AspenTech. All rights reserved.
Reach Your
True
Potential
Accessing Variables
Objective:
Become familiar with referencing flowsheet variables
Aspen Plus References:
User Guide, Chapter 18, Accessing Flowsheet Variables
•
®
Related Topics:
• User Guide, Chapter 20, Sensitivity
• User Guide, Chapter 21, Design Specifications
• User Guide, Chapter 19, Fortran Blocks and In-Line Fortran
• User Guide, Chapter 22, Optimization
Aspen Plus
• User Guide, Chapter 23,Introduction
Fitting ato Simulation
Model to Data
147
©1998 AspenTech. All rights reserved.
Why Access Variables?
OVHD
FEED
COLUMN
BTMS
•
What is the effect of the reflux ratio of the column on the
purity (mole fraction of component B) of the distillate?
•
To perform this analysis, references must be made to 2
flowsheet quantities, i.e. 2 flowsheet variables must be
accessed:
1. The reflux ratio of the column
2. The mole fraction of component B in the stream
OVHD
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 148
©1998 AspenTech. All rights reserved.
Accessing Variables
• An accessed variable is a reference to a particular
flowsheet quantity, e.g. temperature of a stream or duty of
a block.
• Accessed variables can be read from, written to, or both.
• Flowsheet result variables (calculated quantities) should
not be overwritten or varied.
• The concept of accessing variables is used in sensitivity
analyses, design specifications, in-line Fortran,
optimization, etc.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 149
©1998 AspenTech. All rights reserved.
Variable Categories
Variable Category
Type of Variable
Blocks
Block variables and vectors
Streams
Stream variables and vectors.
Both non-component variables and
component dependent flow and composition
variables can be accessed.
Model Utility
Parameters, balance block and pressure
relief variables
Property
Property parameters
Reactions
Reactions and chemistry variables
Costing
Costing variables
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 150
©1998 AspenTech. All rights reserved.
Variable Definition Dialog Box
•
When completing a Define sheet, such as on a Fortran,
Design specification or Sensitivity form, specify the
variables on the Variable Definition dialog box.
•
•
You cannot modify the variables on the Define sheet itself.
•
If you are editing an existing variable and want to change
the variable name, click the right mouse button on the
Variable Name field. On the popup menu, click Rename.
On the Variable Definition dialog box, select the variable
category and Aspen Plus will display the other fields
necessary to complete the variable definition.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 151
©1998 AspenTech. All rights reserved.
Notes
1. If the Mass-Frac, Mole-Frac or StdVol-Frac of a component in
a stream is accessed, it should not be modified. To modify the
composition of a stream, access and modify the Mass-Flow,
Mole-Flow or StdVol-Flow of the desired component.
2. If duty is specified for a block, that duty can be read and written
using the variable DUTY for that block. If the duty for a block is
calculated during simulation, it should be read using the
variable QCALC.
3. PRES is the specified pressure or pressure drop, and PDROP
is pressure drop used in calculating pressure profile in heating
or cooling curves.
4. Only streams that are feeds to the flowsheet should be varied
or modified directly.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 152
©1998 AspenTech. All rights reserved.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 153
©1998 AspenTech. All rights reserved.
Reach Your
True
Potential
Sensitivity Analysis
Objective:
Introduce the use of sensitivity analysis to study
relationships between process variables
Aspen Plus References:
• User Guide, Chapter 20, Sensitivity
Related Topics:
• User Guide, Chapter 18, Accessing Flowsheet Variables
• User Guide, Chapter 19,Introduction
FortrantoBlocks
and In-Line Fortran
Aspen Plus
®
154
©1998 AspenTech. All rights reserved.
Sensitivity Analysis
• Allows user to study the effect of changes in input
variables on process outputs.
• Results can be viewed by looking at the Results form in
the folder for the Sensitivity block.
• Results may be graphed to easily visualize relationships
between different variables.
• Changes made to a flowsheet input quantity in a
sensitivity block do not affect the simulation. The
sensitivity study is run independently of the base-case
simulation.
• Located under /Data/Model Analysis Tools/Sensitivity
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 155
©1998 AspenTech. All rights reserved.
Sensitivity Analysis Example
RECYCLE
REACTOR
COOL
FEED
REAC-OUT
COOL-OUT
SEP
Filename: CUMENE-S.BKP
PRODUCT
What is the effect of cooler outlet temperature on the purity
of the product stream?
• What is the manipulated (varied) variable?
» Cooler outlet temperature
• What is the measured (sampled) variable?
» Purity (mole fraction) of cumene in product stream
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 156
©1998 AspenTech. All rights reserved.
Sensitivity Analysis Results
What is happening below 75 F and above 300 F?
Sensitivity S-1 Results Summary
CUMENE PRODUCT PURITY
0.85
0.9
0.95
1
•
50
75 100 125 150 175 200 225 250 275 300 325 350
VARY 1 COOL PARAM TEMP F
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 157
©1998 AspenTech. All rights reserved.
Uses of Sensitivity Analysis
• Studying the effect of changes in input variables on
process (model) outputs
• Graphically representing the effects of input variables
• Verifying that a solution to a design specification is
feasible
• Rudimentary optimization
• Studying time varying variables using a quasi-steadystate approach
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 158
©1998 AspenTech. All rights reserved.
Steps for Using Sensitivity Analysis
1. Specify measured (sampled) variable(s)
- These are quantities calculated during the simulation to
be used in step 4 (Sensitivity Input Define sheet).
2. Specify manipulated (varied) variable(s)
- These are the flowsheet variables to be varied
(Sensitivity Input Vary sheet).
3. Specify range(s) for manipulated (varied) variable(s)
- Variation for manipulated variable can be specified either
as equidistant points within an interval or as a list of
values for the variable (Sensitivity Input Vary sheet).
4. Specify quantities to calculate and tabulate
- Tabulated quantities can be any valid Fortran expression
containing variables defined in step 1 (Sensitivity Input
Tabulate sheet).
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 159
©1998 AspenTech. All rights reserved.
Plotting
1. Select the column containing the X-axis variable and then
select X-Axis Variable from the Plot menu.
2. Select the column containing the Y-axis variable and then
select Y-Axis Variable from the Plot menu.
3. (Optional) Select the column containing the parametric
variable and then select Parametric Variable from the
Plot menu.
4. Select Display Plot from the Plot menu.
» To select a column, click on the heading of the column
with the left mouse button.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 160
©1998 AspenTech. All rights reserved.
Notes
1. Only quantities that have been input to the flowsheet
should be varied or manipulated.
2. Multiple inputs can be varied.
3. The simulation is run for every combination of
manipulated (varied) variables.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 161
©1998 AspenTech. All rights reserved.
Sensitivity Analysis Workshop
Objective: Use a sensitivity analysis to study the effect of
the recycle flowrate on the reactor duty in the cyclohexane
flowsheet
Part A:
Using the cyclohexane production flowsheet Workshop (saved as
CYCLOHEX.BKP), plot the variation of reactor duty (block REACT) as
the recycle split fraction in LFLOW is varied from 0.1 to 0.4.
Optional Part B:
In addition to the fraction split off as recycle (Part A), vary the
conversion of benzene in the reactor from 0.9 to 1.0. Tabulate the
reactor duty and construct a parametric plot showing the dependence of
reactor duty on the fraction split off as recycle and conversion of
benzene.
Note: Both of these studies (parts A and B) should be set up within the
same sensitivity analysis block.
When finished, save as filename: SENS.BKP.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 162
©1998 AspenTech. All rights reserved.
Cyclohexane Production Workshop
C6 H6
+ 3 H2
=
C 6H12
Benzene
Hydrogen
Cyclohexane
PURGE
Total flow = 330 kmol/hr
T = 50 C
P = 25 bar
Molefrac H2 = 0.975
N2 = 0.005
CH4 = 0.02
H2IN
92% flow to stream H2RCY
VFLOW
H2RCY
VAP
FEED-MIX
REACT
RXIN
BZIN
T = 150C
P = 23 bar
T = 40 C
P = 1 bar
Benzene flow = 100 kmol/hr
HP-SEP
T = 200 C
Pdrop = 1 bar
Benzene conv =
0.998
LTENDS
T = 50 C
Pdrop = 0.5 bar
RXOUT
Theoretical Stages = 12
Reflux ratio = 1.2
Bottoms rate = 99 kmol/hr
Partial Condenser with
vapor distillate only
Column Pressure = 15 bar
Feed stage = 8
LIQ
CHRCY
COLFD
LFLOW
30% flow to stream CHRCY
Use the RK-SOAVE property method
PRODUCT
COLUMN
Specify cyclohexane mole
recovery of 0.9999 by varying
Bottoms rate from 97 to 101 kmol/hr
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 163
©1998 AspenTech. All rights reserved.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 164
©1998 AspenTech. All rights reserved.
Reach Your
True
Potential
Design Specifications
Objective:
Introduce the use of design specifications to meet process
design requirements
Aspen Plus References:
• User Guide, Chapter 21, Design Specifications
Related Topics:
• User Guide, Chapter 18, Accessing Flowsheet Variables
• User Guide, Chapter 19, Fortran Blocks and In-Line Fortran
• User Guide, Chapter 17, Convergence
Introduction to Aspen Plus
®
165
©1998 AspenTech. All rights reserved.
Design Specifications
• Similar to a feedback controller
• Allows user to set the value of a calculated flowsheet
quantity to a particular value
• Objective is achieved by manipulating a specified input
variable
• No results associated directly with a design specification
• Located under /Data/Flowsheeting Options/Design Specs
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 166
©1998 AspenTech. All rights reserved.
Design Specification Example
RECYCLE
REACTOR
COOL
FEED
REAC-OUT
COOL-OUT
SEP
Filename: CUMENE-D.BKP
PRODUCT
What should the cooler outlet temperature be to achieve a
cumene product purity of 98 mole percent?
•
What is the manipulated (varied) variable?
» Cooler outlet temperature
•
What is the measured (sampled) variable?
» Mole fraction of cumene in stream PRODUCT
•
What is the specification (target) to be achieved?
» Mole fraction of cumene in stream PRODUCT = 0.98
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 167
©1998 AspenTech. All rights reserved.
Steps for Using Design Specifications
1. Identify measured (sampled) variables
These are flowsheet quantities, usually calculated
quantities, to be included in the objective function
(Design Spec Define sheet).
2. Specify objective function (Spec) and goal (Target)
This is the equation that the specification attempts to
satisfy (Design Spec Spec sheet). The units of the
variable used in the objective function are the units for
that type of variable as specified by the Units Set
declared for the design specification.
3. Set tolerance for objective function
The specification is said to be converged if the objective
function equation is satisfied to within this tolerance
(Design Spec Spec sheet).
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 168
©1998 AspenTech. All rights reserved.
Steps for Using Design Specifications (Continued)
4. Specify manipulated (varied) variable
This is the variable whose value the specification
changes in order to satisfy the objective function
equation (Design Spec Vary sheet).
5. Specify range of manipulated (varied) variable
These are the lower and upper bounds of the interval
within which Aspen Plus will vary the manipulated
variable (Design Spec Vary sheet). The units of the
limits for the varied variable are the units for that type of
variable as specified by the Units Set declared for the
design specification.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 169
©1998 AspenTech. All rights reserved.
Notes
1. Only quantities that have been input to the flowsheet
should be manipulated.
2. The calculations performed by a design specification are
iterative. Providing a good estimate for the manipulated
variable will help the design specification converge in
fewer iterations. This is especially important for large
flowsheets with several interrelated design specifications.
3. The results of a design specification can be found under
Data/Convergence/Convergence, by opening the
appropriate solver block, and choosing the Results form.
Alternatively, the final values of the manipulated and/or
sampled variables can be viewed directly on the
appropriate Stream/Block results forms.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 170
©1998 AspenTech. All rights reserved.
Notes (Continued)
4. If a design-spec does not converge:
a. Check to see that the manipulated variable is not at
its lower or upper bound.
b. Verify that a solution exists within the bounds
specified for the manipulated variable, perhaps by
performing a sensitivity analysis.
c. Check to ensure that the manipulated variable does
indeed affect the value of the sampled variables.
d. Try providing a better starting estimate for the value
of the manipulated variable.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 171
©1998 AspenTech. All rights reserved.
Notes (Continued)
e. Try changing the characteristics of the convergence
block associated with the design-spec (step size,
number of iterations, algorithm, etc.)
f. Try narrowing the bounds of the manipulated variable
or loosening the tolerance on the objective function
to help convergence.
g. Make sure that the objective function does not have a
flat region within the range of the manipulated
variable.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 172
©1998 AspenTech. All rights reserved.
Design Specification Workshop
Objective: Use a design specification in the cyclohexane
flowsheet to fix the heat load on the reactor by varying the
recycle flowrate.
The cyclohexane production flowsheet workshop (saved as
CYCLOHEX.BKP) is a model of an existing plant. The cooling system
around the reactor can handle a maximum operating load of 4.7
MMkcal/hr. Determine the amount of cyclohexane recycle necessary to
keep the cooling load on the reactor to this amount.
Note: The heat convention used in Aspen Plus is that heat input to a
block is positive, and heat removed from a block is negative.
When finished, save as filename: DES-SPEC.BKP
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 173
©1998 AspenTech. All rights reserved.
Cyclohexane Production Workshop
C6 H6
+ 3 H2
=
C 6H12
Benzene
Hydrogen
Cyclohexane
PURGE
Total flow = 330 kmol/hr
T = 50 C
P = 25 bar
Molefrac H2 = 0.975
N2 = 0.005
CH4 = 0.02
H2IN
92% flow to stream H2RCY
VFLOW
H2RCY
VAP
FEED-MIX
REACT
RXIN
BZIN
T = 150C
P = 23 bar
T = 40 C
P = 1 bar
Benzene flow = 100 kmol/hr
HP-SEP
T = 200 C
Pdrop = 1 bar
Benzene conv =
0.998
LTENDS
T = 50 C
Pdrop = 0.5 bar
RXOUT
Theoretical Stages = 12
Reflux ratio = 1.2
Bottoms rate = 99 kmol/hr
Partial Condenser with
vapor distillate only
Column Pressure = 15 bar
Feed stage = 8
LIQ
CHRCY
COLFD
LFLOW
30% flow to stream CHRCY
Use the RK-SOAVE property method
PRODUCT
COLUMN
Specify cyclohexane mole
recovery of 0.9999 by varying
Bottoms rate from 97 to 101 kmol/hr
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 174
©1998 AspenTech. All rights reserved.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 175
©1998 AspenTech. All rights reserved.
Reach Your
True
Potential
Fortran Blocks
Objective:
Introduce usage of Fortran blocks in Aspen Plus
Aspen Plus References:
• User Guide, Chapter 19, Fortran Blocks and In-Line Fortran
®
Related Topics:
• User Guide, Chapter 20, Sensitivity
• User Guide, Chapter 21, Design Specifications
• User Guide, Chapter 18, Accessing Flowsheet Variables
to Aspen Plus
• User Guide, Chapter 22,Introduction
Optimization
176
©1998 AspenTech. All rights reserved.
Fortran Blocks
• Allows user to write Fortran to be executed by Aspen Plus
• Simple Fortran can be translated by Aspen Plus and does
not need to be compiled.
• A Fortran compiler must be present on the machine where
the Aspen Plus engine is running to compile more
complex Fortran code.
• Results of the execution of a Fortran block must be
viewed by directly examining the values of the variables
modified by the Fortran block.
• Located under /Data/Flowsheeting Options/Fortran
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 177
©1998 AspenTech. All rights reserved.
Fortran Block Example
Use of a Fortran block to set the pressure drop across a
Heater block.
RECYCLE
REACTOR
COOL
FEED
REAC-OUT
V
COOL-OUT
DELTA-P
Fortran Block
DELTA-P = -10-9 * V2
SEP
PRODUCT
Filename: CUMENE-F.BKP
Pressure drop across heater is proportional to square of
volumetric flow into heater.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 178
©1998 AspenTech. All rights reserved.
Fortran Block Example (Continued)
• Which flowsheet variables must be accessed?
» Volumetric flow of stream REAC-OUT
This can be accessed in two different ways:
1. Mass flow and mass density of stream REAC-OUT
2. A prop-set containing volumetric flow of a mixture
» Pressure drop across block COOL
• When should the Fortran block be executed?
» Before block COOL
• Which variables are read and which are written?
» Volumetric flow is read
» Pressure drop is written
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 179
©1998 AspenTech. All rights reserved.
Uses of Fortran Blocks
• Feed-forward control (setting flowsheet inputs based on
upstream calculated values)
• Calling external subroutines
• Input / output to and from external files
• Writing to Control Panel, History File, or Report File
• Custom reports
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 180
©1998 AspenTech. All rights reserved.
Fortran Interpreter
•
•
Aspen Plus will interpret in-line Fortran if it is possible.
The following Fortran can be interpreted:
Arithmetic expressions and assignment statements
IF statements
GOTO statements, except assigned GOTO
WRITE statements that do not have unformatted text in them
FORMAT statements
CONTINUE statements
DO loops
Calls to some built-in Fortran functions
REAL or INTEGER statements*
DOUBLE PRECISION statements*
DIMENSION statements*
* Enter on the Declaration sheet.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 181
©1998 AspenTech. All rights reserved.
Built-In Fortran Functions
•
Calls to some built-in Fortran functions:
DABS
DACOS
DASIN
DATAN
DATAN2
DCOS
DCOSH
DCOTAN
•
DMIN1
DMOD
DSIN
DSINH
DSQRT
DTAN
DTANH
IABS
IDINT
MAX0
MIN0
MOD
You can also use the equivalent single precision or
generic function names. But, Aspen Plus always
performs double precision calculations.
Septiembre 12, 2001
®
DERF
DEXP
DFLOAT
DGAMMA
DLGAMA
DLOG
DLOG10
DMAX1
Introduction to Aspen Plus
Slide 182
©1998 AspenTech. All rights reserved.
Statements Requiring Compilation
•
The following statements require compilation:
CALL
CHARACTER
COMMON
COMPLEX
DATA
ENTRY
EQUIVALENCE
IMPLICIT
Septiembre 12, 2001
®
LOGICAL
PARAMETER
PRINT
RETURN
READ
STOP
SUBROUTINE
Introduction to Aspen Plus
Slide 183
©1998 AspenTech. All rights reserved.
Steps for Using Fortran Blocks
1. Access flowsheet variables to be used within Fortran
- All flowsheet quantities that must be either read from
or written to, must be identified (Fortran Input Define
sheet).
2. Write Fortran
- Includes both non-executable (COMMON,
EQUIVALENCE, etc) Fortran (Fortran Input
Declarations sheet) and executable Fortran (Fortran
Input Fortran sheet) to achieve desired result.
3. Specify location of Fortran block in execution sequence
(Fortran Input Sequence sheet)
- Specify directly, or
- Specify with read and write variables
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 184
©1998 AspenTech. All rights reserved.
Notes
1. Only quantities that have been input to the flowsheet
should be overwritten.
2. The rules for writing In-Line Fortran are as follows:
a. The Fortran code must begin in column 7 or beyond.
b. Comment lines must have the letter “C” or a “ ; ” in
the first column.
c. Column two must be blank.
3. Variable names should not begin with lZ or ZZ.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 185
©1998 AspenTech. All rights reserved.
Notes (Continued)
4. On the Fortran Input Sequence sheet, the preferred way
to specify where the Fortran block should be executed is
to list the read and write variables.
5. When using the Fortran WRITE statement, you can use
the predefined unit number NTERM to write to the control
panel. For example,
write(NTERM,*) flow
OR
write(NTERM,10) flow
10 format(‘Feed flowrate =‘,G12.5)
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 186
©1998 AspenTech. All rights reserved.
Fortran Workshop
Objective: Use a Fortran Block to maintain the methane:water
ratio in the feed to a reactor.
In a methane reformer, hydrogen gas is produced by reacting methane
with water, generating carbon monoxide as a by-product. The reaction
taking place is the following:
The feed to the reformer consists of pure methane and water streams.
These are mixed and heated prior to being fed to the reformer. The
conversion of methane is 99.5%, and the molar ratio of methane to
water in the feed is 1:4.
Create a flowsheet as shown in the diagram on the following slide. Set
up a Sensitivity block and plot a graph showing the variation of reactor
duty as the methane flowrate in the feed is varied from 100 to 500
lbmol/hr.
Note: The methane:water ratio in the feed must be maintained
constant for each Sensitivity case. (Hint: This can be
achieved using a Fortran Block.)
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 187
©1998 AspenTech. All rights reserved.
Fortran Workshop (Continued)
CH4 + H2O =
3 H2
+
CO
Methane Water Hydrogen Carbon Monoxide
Temperature = 150 F
Pressure = 900 psia
CH4
REFORMER
MIX
RXIN
Temperature = 70 F
Pressure = 15 psia
RXOUT
H2O
Temperature = 1100 F
Pressure = 850 psia
Temperature = 1450 F
Pressure Drop = 20 psi
CH4 conversion = 0.995
Use the Peng-Robinson Property Method
When finished, save as
filename: Fortran.BKP
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 188
©1998 AspenTech. All rights reserved.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 189
©1998 AspenTech. All rights reserved.
Reach Your
True
Potential
Windows Interoperability
Objective:
Introduce the use of windows interoperability to transfer
data easily to and from other Windows programs.
Aspen Plus References:
• User Guide, Chapter 37, Working with Other Windows Programs
• User Guide, Chapter 38, Using the Aspen Plus ActiveX Automation
Server
Introduction to Aspen Plus
190
®
©1998 AspenTech. All rights reserved.
Windows Interoperability
•
Copying and pasting simulation data into spreadsheets
or reports
•
Copying and pasting flowsheet graphics and plots into
reports
•
Creating active links between Aspen Plus and other
Windows applications
•
•
OLE embedding
ActiveX automation
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 191
©1998 AspenTech. All rights reserved.
Windows Interoperability - Examples
• Copy simulation results such as column profiles and
stream results into
- Spreadsheet for further analysis
- Word processor for reports and documentation
- Design program
- Database for case storage and management
•
Copy flowsheet graphics and plots into
- Word processor for reports
- Slide making program for presentations
•
Copy tabular data from spreadsheets into Aspen Plus
for Data Regression, Data-Fit, etc.
•
Copy plots or tables into the Process Flowsheet
Window.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 192
©1998 AspenTech. All rights reserved.
Benefits of Windows Interoperability
•
Benefits of Copy/Paste/Paste Link
- Live data links can be established that update these
applications as the process model is changed to
automatically propagate results of engineering
changes.
- The benefits to the engineer are quick and error-free
data transfer and consistent engineering results
throughout the engineering work process.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 193
©1998 AspenTech. All rights reserved.
Steps for Using Copy and Paste
1. Select
Select the data fields or the graphical objects.
- Multiple fields of data or objects can be selected by
holding down the CTRL key while clicking the mouse
on the fields.
- Columns of data can be selected by clicking the
column heading, or an entire grid can be selected by
clicking on the top left cell.
2. Copy
Choose Copy from the Edit menu or type CTRL-C.
3. Paste
Click the mouse in the input field where you want the
information and choose Paste from the Edit menu or
click CTRL-V.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 194
©1998 AspenTech. All rights reserved.
OLE Embedding
•
What is OLE embedding?
- Applications can be used within applications.
•
Uses of OLE embedding
- Aspen Plus as the OLE server: Aspen Plus
flowsheet graphics can be embedded into a report
document, or stream data into a CAD drawing. The
simulation model is actually contained in the
document, and could be delivered directly with that
document.
- Aspen Plus as the OLE container: Other windows
applications can be embedded within the Aspen
Plus simulation.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 195
©1998 AspenTech. All rights reserved.
OLE Embedding (Continued)
•
Examples of OLE embedding
- OLE server: If the recipient of an engineering report,
for example, wanted to review the model
assumptions, he could access and run the
embedded Aspen Plus model directly from the report
document.
- OLE container: For example, Excel spreadsheets
and plots could be used to enhance Aspen Plus
flowsheet graphics.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 196
©1998 AspenTech. All rights reserved.
Embedding Objects in the Flowsheet
•
You can embed other applications as objects into the
Process Flowsheet window.
•
You can do this in two ways:
- Using Copy and Paste
- Using the Insert dialog box
•
You can edit the object embedded in the flowsheet by
double clicking on the object to edit it inside Aspen Plus.
•
You can also move, resize or attach the object to a block
or stream in the flowsheet.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 197
©1998 AspenTech. All rights reserved.
Copy and Paste Workshop 1
Objective: Use copy and paste to copy and paste the
stage temperatures into a spreadsheet.
• Use the Cyclohexane flowsheet workshop (saved as
CYCLOHEX.BKP)
• Copy the temperature profile from COLUMN into a
spreadsheet.
• Generate a plot of the temperature using the plot wizard
and copy and paste the plot into the spreadsheet.
• Save the spreadsheet as CYCLOHEX-result.xls
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 198
©1998 AspenTech. All rights reserved.
Copy and Paste Workshop 2
Objective: Use copy and paste to copy the stream
results to a stream input form.
• Use the Cyclohexane flowsheet workshop (saved as
CYCLOHEX.BKP)
• Copy the stream results from stream RXIN into the input
form.
- Copy the compositions, the temperature and the
pressure separately.
Note: Reinitialize before running the simulation in order to
see how many iterations are needed before and after the
estimate is added.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 199
©1998 AspenTech. All rights reserved.
Creating Active Links
•
When copying and pasting information, you can create
active links between input or results fields in Aspen
Plus and other applications such as Word and Excel.
•
The links update these applications as the process
model is modified to automatically propagate results of
engineering changes.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 200
©1998 AspenTech. All rights reserved.
Steps for Creating Active Links
1. Open both applications.
2. Select the data (or object) that you want to paste and
link.
3. Choose Copy from the Edit menu.
4. In the location where you want to paste the link, choose
Paste Special from the Edit menu.
5. In the Paste Special dialog box, click the Paste Link
radio button.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 201
©1998 AspenTech. All rights reserved.
Paste Link Demonstration
Objective: Create an active link from Aspen Plus
Results into a spreadsheet.
•
•
Start with the cumene flowsheet demonstration.
•
•
Copy and paste the link into the Aspen Plus flowsheet.
•
Change the temperature in the spreadsheet and then
rerun the flowsheet. Notice the changes.
Open a spreadsheet and create a cell with the
temperature for the cooler in it.
Copy and paste a link with the flow and composition of
cumene in the product stream into the spreadsheet.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 202
©1998 AspenTech. All rights reserved.
Paste Link Workshop
Objective: Create an active link from Aspen Plus results
into a spreadsheet
•
Use the Cyclohexane flowsheet workshop (saved as
CYCLOHEX.BKP)
•
Copy the Condenser and Reboiler duty results from the
RadFrac COLUMN Summary sheet. Use Copy with Format
and copy the value, the label and the units.
•
Paste the results into the CYCLOHEX-results.xls spreadsheet
as a link. Use Paste Special and choose Link.
•
Change the Reflux ratio in the column to 2 and rerun the
flowsheet. Check the spreadsheet to see that the results have
changed there also. Notice that the temperature profile results
have not changed since they were not pasted as a link.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 203
©1998 AspenTech. All rights reserved.
Saving Files with Active Links
•
Be sure to save both the link source file and the link
container file.
•
If you save the link source with a different name, you
must save the link container after saving the link
source.
•
If you have active links in both directions between the
two applications and you change the name of both files,
you must do three Save operations:
- Save the first application with a new name.
- Save the second application with a new name.
- Save the first application again.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 204
©1998 AspenTech. All rights reserved.
Running Files with Active Links
•
When you open the link source file, there is nothing
special that you need to do.
•
When you open the link container file, you will usually
see a dialog box asking you if you want to re-establish
the links. You can select Yes or No.
•
To make a link source application visible:
- Select Links, from the Edit menu in Aspen Plus.
- In the Links dialog box, select the source file and
click Open Source.
(Note: The Process Flowsheet must be the active
window. Links is not an option on the Edit menu if
the Data Browser is active.)
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 205
©1998 AspenTech. All rights reserved.
ActiveX Automation
•
What is ActiveX automation?
- Other programs such as Visual Basic or C++ can be
used to control a simulation.
•
Uses of ActiveX automation
- Visual Basic or C++ can be written to access and
control process models using a documented
interface syntax.
- Custom applications can be built on top of process
models.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 206
©1998 AspenTech. All rights reserved.
OLE Automation (Continued)
•
Benefits of ActiveX automation
- A model developer in the Process Engineering
department could develop a customized Excel
interface to an Aspen Plus model for plant operators,
using the Visual Basic for Applications (VBA) macro
language.
- A customer might write a top-level C++ program that
• pulls data from a process model
• uses that data to automatically generate custom
spec sheets
• populates a process engineering database
• launches a third-party design program
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 207
©1998 AspenTech. All rights reserved.
OLE Automation Demonstration
•
Demonstration 1
- Simple run and reinit button are used in the butanol
flowsheet.
- Files: butanol-demo.xls and butanol.bkp
•
Demonstration 2
- More elaborate Visual Basic code is used to create a
general heat exchanger spreadsheet that can
access the heat exchangers in any Aspen Plus
flowsheet.
- Files: olespecsheet.xls and heatx2.bkp
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 208
©1998 AspenTech. All rights reserved.
Visual Basic Examples
» Located in the APUI100\VBExample directory
•
•
•
•
•
•
•
•
•
•
•
•
Open - open existing simulation
Run - changes a simulation parameter and re-runs the simulation
ListBlocks - retrieves a list of blocks and their attributes
Connectivity - displays a table showing flowsheet connectivity
GetCollection - illustrates use of a collection object
GetScalarValues - retrieves scalar variables from a block
TempProf - retrieves values for a non-scalar variable with one identifier
CompProf - retrieves values for a non-scalar variable with two identifiers
ReacCoeff - retrieves values for a non-scalar variable with three identifiers
UnitChange - shows changing the units of measurement of a variable
UnitConversion - retrieves a value both in the display units (psi) and
alternative units (atm)
UnitString - retrieves the units of measurement symbol for a variable
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 209
©1998 AspenTech. All rights reserved.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 210
©1998 AspenTech. All rights reserved.
Reach Your
True
Potential
Heat Exchangers
Objective:
Introduce the unit operation models used for heat
exchangers and heaters.
Aspen Plus References:
• Unit Operation Models Reference Manual, Chapter 3,
Heat Exchangers
Introduction to Aspen Plus
®
211
©1998 AspenTech. All rights reserved.
Heat Exchanger Blocks
•
•
•
•
•
Heater - Heater or cooler
HeatX - Two stream heat exchanger
MHeatX - Multi-stream heat exchanger
Hetran - Interface to B-JAC Hetran block
Aerotran - Interface to B-JAC Aerotran block
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 212
©1998 AspenTech. All rights reserved.
Working with the Heater Model
The Heater block mixes multiple inlet streams to produce a
single outlet stream at a specified thermodynamic state.
Heater can be used to represent:
- Heaters
- Coolers
- Valves
- Pumps (when work-related results are not needed)
- Compressors (when work-related results are not
needed)
Heater can also be used to set the thermodynamic conditions
of a stream.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 213
©1998 AspenTech. All rights reserved.
Heater Input Specifications
Allowed combinations:
•
Pressure (or Pressure drop) and one of:
- Outlet temperature
- Heat duty or inlet heat stream
- Vapor fraction
- Temperature change
- Degrees of subcooling or superheating
•
Outlet Temperature or Temperature change and one of:
- Pressure
- Heat Duty
- Vapor fraction
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 214
©1998 AspenTech. All rights reserved.
Heater Input Specifications (Continued)
For single phase use Pressure (drop) and one of:
- Outlet temperature
- Heat duty or inlet heat stream
- Temperature change
Vapor fraction of 1 means dew point condition,
0 means bubble point
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 215
©1998 AspenTech. All rights reserved.
Heat Streams
•
Any number of inlet heat streams can be specified for a
Heater.
•
One outlet heat stream can be specified for the net heat
load from a Heater.
•
The net heat load is the sum of the inlet heat streams
minus the actual (calculated) heat duty.
•
If you give only one specification (temperature or
pressure), Heater uses the sum of the inlet heat
streams as a duty specification.
•
If you give two specifications, Heater uses the heat
streams only to calculate the net heat duty.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 216
©1998 AspenTech. All rights reserved.
Working with the HeatX Model
•
HeatX can perform simplified or rigorous rating
calculations.
•
Simplified rating calculations (heat and material
balance calculations) can be performed if exchanger
geometry is unknown or unimportant.
•
For rigorous heat transfer and pressure drop
calculations, the heat exchanger geometry must be
specified.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 217
©1998 AspenTech. All rights reserved.
Working with the HeatX Model (Continued)
HeatX can model shell-and-tube exchanger types:
- Counter-current and co-current
- Segmental baffle TEMA E, F, G, H, J and X shells
- Rod baffle TEMA E and F shells
- Bare and low-finned tubes
HeatX performs:
- Full zone analysis
- Heat transfer and pressure drop calculations
- Sensible heat, nucleate boiling, condensation
film coefficient calculations
- Built-in or user specified correlations
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 218
©1998 AspenTech. All rights reserved.
Working with the HeatX Model (Continued)
HeatX cannot:
•
•
•
Perform design calculations
Perform mechanical vibration analysis
Estimate fouling factors
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 219
©1998 AspenTech. All rights reserved.
HeatX Input Specifications
Select one of the following specifications:
•
•
•
Heat transfer area or Geometry
Exchanger duty
For hot or cold outlet stream:
- Temperature
- Temperature change
- Temperature approach
- Degrees of superheating / subcooling
- Vapor fraction
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 220
©1998 AspenTech. All rights reserved.
Working with the MHeatX Model
•
MHeatX can be used to represent heat transfer
between multiple hot and cold streams.
•
Detailed, rigorous internal zone analysis can be
performed to determine pinch points.
•
MHeatX uses multiple Heater blocks and heat streams
to enhance flowsheet convergence.
•
Two-stream heat exchangers can also be modeled
using MHeatX.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 221
©1998 AspenTech. All rights reserved.
HeatX versus Heater
Consider the following:
•
•
Use HeatX when both sides are important.
•
Use two Heaters (coupled by heat stream, Fortran
block or design spec) or an MHeatX to avoid flowsheet
complexity created by HeatX.
Use Heater when one side (e.g. the utility) is not
important.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 222
©1998 AspenTech. All rights reserved.
Two Heaters versus One HeatX
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 223
©1998 AspenTech. All rights reserved.
Working with Hetran and Aerotran
•
The Hetran block is the interface to the B-JAC Hetran
program for designing and simulating shell and tube
heat exchangers.
•
The Aerotran block is the interface to the B-JAC
Aerotran program for designing and simulating aircooled heat exchangers.
•
Information related to the heat exchanger configuration
and geometry is entered through the Hetran or Aerotran
standalone program interface.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 224
©1998 AspenTech. All rights reserved.
Heat Curves
All of the heat exchanger models are able to calculate
Heat Curves (Hcurves).
Tables can be generated for various independent
variables (typically duty or temperature) for any
property that Aspen Plus can generate.
These tables can be printed, plotted, or exported for use
with other heat exchanger design software.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 225
©1998 AspenTech. All rights reserved.
Heat Curves Tabular Results
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 226
©1998 AspenTech. All rights reserved.
Heat Curve Plot
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 227
©1998 AspenTech. All rights reserved.
HeatX Workshop
Objective: Compare the simulation of a heat exchanger
that uses water to cool a hydrocarbon mixture using three
methods: a shortcut HeatX, a rigorous HeatX and two
Heaters connected with a Heat stream.
•
Hydrocarbon stream
- Temperature: 200 C
- Pressure: 4 bar
- Flowrate: 10000 kg/hr
- Composition: 50 wt% benzene, 20% styrene,
20% ethylbenzene and 10% water
•
Cooling water
- Temperature: 20 C
- Pressure: 10 bar
- Flow rate: 60000 kg/hr
- Composition: 100% water
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 228
©1998 AspenTech. All rights reserved.
HeatX Workshop (Continued)
When finished, save as filename: HEATX.BKP
HEATER-1
HCLD-IN
HCLD-OUT
SHOT-OUT
RHOT-OUT
SHEATX
SCLD-IN
SCLD-OUT
RHEATX
RCLD-IN
RCLD-OUT
Q-TRANS
HEATER-2
HHOT-IN
HHOT-OUT
SHOT-IN
RHOT-IN
Use the NRTL-RK Property Method for the hydrocarbon streams.
Specify that the valid phases for the hydrocarbon stream is Vapor-Liquid-Liquid.
Specify that the Steam Tables are used to calculate the properties for the cooling water
streams on the Block BlockOptions Properties sheet.
Start with the General with Metric Units Template.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 229
©1998 AspenTech. All rights reserved.
HeatX Workshop (Continued)
•
Shortcut HeatX simulation:
- Hydrocarbon stream exit has a vapor fraction of 0
- No pressure drop in either stream
•
Two Heaters simulation:
- Use the same specifications as the shortcut HeatX simulation
•
Rigorous HeatX simulation:
- Hydrocarbons in shell leave with a vapor fraction of 0
- Shell diameter 1 m, 1 tube pass
- 300 bare tubes, 3 m length, pitch 31 mm, 21 mm ID, 25 mm OD
- All nozzles 100 mm
- 5 baffles, 15% cut
- Create heat curves containing all info required for thermal design.
- Change the heat exchanger specification to Geometry and re-run.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 230
©1998 AspenTech. All rights reserved.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 231
©1998 AspenTech. All rights reserved.
Reach Your
True
Potential
Pressure Changers
Objective:
Introduce the unit operation models used to change
pressure: pumps, compressors, and models for
calculating pressure change through pipes and valves.
Aspen Plus References:
• Unit Operation Models Reference Manual, Chapter 6, Pressure
Changers
Introduction to Aspen Plus
®
232
©1998 AspenTech. All rights reserved.
Pressure Changer Blocks
•
•
•
•
•
•
Pump - Pump or hydraulic turbine
Compr - Compressor or turbine
MCompr - Multi-stage compressor or turbine
Valve - Control valve
Pipe - Single-segment pipe
Pipeline - Multi-segment pipe
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 233
©1998 AspenTech. All rights reserved.
Working with the Pump Model
•
The Pump block can be used to simulate:
- Pumps
- Hydraulic turbines
•
•
Power requirement is calculated or input.
•
•
Pump is designed to handle a single liquid phase.
A Heater model can be used for pressure change
calculations only.
Vapor-liquid or vapor-liquid-liquid calculations can be
specified to check outlet stream phases.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 234
©1998 AspenTech. All rights reserved.
Pump Performance Curves
•
Rating can be done by specifying scalar parameters or
a pump performance curve.
•
Specify:
- Dimensional curves
• Head versus flow
• Power versus flow
- Dimensionless curves:
• Head coefficient versus flow coefficient
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 235
©1998 AspenTech. All rights reserved.
Working with the Compr Model
•
The Compr block can be used to simulate:
- Polytropic centrifugal compressor
- Polytropic positive displacement compressor
- Isentropic compressor
- Isentropic turbine
•
•
•
MCompr is used for multi-stage compressors.
•
Compr is designed to handle both single and multiple
phase calculations.
Power requirement is calculated or input.
A Heater model can be used for pressure change
calculations only.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 236
©1998 AspenTech. All rights reserved.
Working with the MCompr Model
•
The MCompr block can be used to simulate:
- Multi-stage polytropic centrifugal compressor
- Multi-stage polytropic positive displacement compressor
- Multi-stage isentropic compressor
- Multi-stage isentropic turbine
•
MCompr can have an intercooler between each stage, and
an aftercooler after the last stage.
- You can perform one-, two-, or three- phase flash
calculations in the intercoolers.
- Each cooler can have a liquid knockout stream, except
the cooler after the last stage.
- Intercooler specifications apply to all subsequent
coolers.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 237
©1998 AspenTech. All rights reserved.
Compressor Performance Curves
•
Rating can be done by specifying a compressor
performance curve.
•
Specify:
- Dimensional curves
• Head versus flow
• Power versus flow
- Dimensionless curves:
• Head coefficient versus flow coefficient
•
Compr cannot handle performance curves for a turbine.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 238
©1998 AspenTech. All rights reserved.
Work Streams
•
Any number of inlet work streams can be specified for
pumps and compressors.
•
One outlet work stream can be specified for the net
work load from pumps or compressors.
•
The net work load is the sum of the inlet work streams
minus the actual (calculated) work.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 239
©1998 AspenTech. All rights reserved.
Working with the Valve Model
•
The Valve block can be used to simulate:
- Control valves
- Pressure drop
•
The pressure drop across a valve is related to the valve
flow coefficient.
•
•
Flow is assumed to be adiabatic.
Valve can perform single or multiple phase calculations.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 240
©1998 AspenTech. All rights reserved.
Working with the Valve Model (Continued)
•
•
The effect of head loss from pipe fittings can be included.
•
•
Valve can check for choked flow.
There are three types of calculations:
- Adiabatic flash for specified outlet pressure (pressure
changer)
- Calculate valve flow coefficient for specified outlet
pressure (design)
- Calculate outlet pressure for specified valve (rating)
Cavitation index can be calculated.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 241
©1998 AspenTech. All rights reserved.
Working with the Pipe Model
•
The Pipe block calculates the pressure drop and heat
transfer in a single pipe segment.
•
The Pipeline block can be used for a multiple-segment
pipe.
•
•
Pipe can perform single or multiple phase calculations.
•
If the outlet pressure is known, Pipe calculates the inlet
pressure and updates the state variables of the inlet
stream.
•
Entrance effects are not modeled.
If the inlet pressure is known, Pipe calculates the outlet
pressure.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 242
©1998 AspenTech. All rights reserved.
Pressure Changers Block Example
Add a Compressor and a Valve to the cumene flowsheet.
COMPR
RECYCLE
VALVE
RECYCLE2
RECYCLE3
Outlet Pressure = 3 psig
Polytropic compressor model
using GPSA method
Discharge pressure = 5 psig
FEED
REAC-OUT
REACTOR
COOL-OUT
SEP
COOL
PRODUCT
Filename: CUMENE-P.BKP
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 243
©1998 AspenTech. All rights reserved.
Pressure Changers Workshop
Objective: Add pressure changer unit operations to the
Cyclohexane flowsheet.
•
Start with the Cyclohexane Workshop flowsheet
(CYCLOHEX.BKP)
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 244
©1998 AspenTech. All rights reserved.
Pressure Changers Workshop (Continued)
Isentropic
4 bar pressure change
COMP
H2IN
PURGE
H2RCY
VFLOW
VAP
H2RCY2
FEED-MIX
PURGE2
20 bar outlet pressure
Globe valve
V810 equal percent flow
1.5-in size
REACT
RXIN
FEEDPUMP
BZIN
VALVE
HP-SEP
RXOUT
BZIN2
CHRCY3
Pump efficiency = 0.6
Driver efficiency = 0.9
LTENDS
LIQ
PIPE
PUMP
CHRCY2
CHRCY
Performance Curve
Head
Flow
[m]
[cum/hr]
40
20
250
10
300
5
400
3
Septiembre 12, 2001
®
Carbon Steel
Schedule 40
1-in diameter
25-m length
COLFD
LFLOW
26 bar outlet pressure
PRODUCT
COLUMN
When finished, save as
filename: PRESCHNG.BKP
Introduction to Aspen Plus
Slide 245
©1998 AspenTech. All rights reserved.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 246
©1998 AspenTech. All rights reserved.
Reach Your
True
Potential
Flowsheet Convergence
Objective:
Introduce the idea of convergence blocks, tear streams
and flowsheet sequences
Aspen Plus References:
• User Guide, Chapter 17, Convergence
Introduction to Aspen Plus
®
247
©1998 AspenTech. All rights reserved.
Convergence Blocks
• Every design specification and tear stream has an
associated convergence block.
• Convergence blocks determine how guesses for a tear
stream or design specification manipulated variable are
updated from iteration to iteration.
• Aspen Plus-defined convergence block names begin with
the character “$.”
- User defined convergence block names must not begin
with the character “$.”
• To determine the convergence blocks defined by Aspen
Plus, look under the “Flowsheet Analysis” section in the
Control Panel messages.
• User convergence blocks can be specified under
/Data/Convergence/Convergence...
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 248
©1998 AspenTech. All rights reserved.
Convergence Block Types
•
Different types of convergence blocks are used for different
purposes:
To converge tear streams:
•
• WEGSTEIN
• DIRECT
• BROYDEN
• NEWTON
To converge design specifications:
• SECANT
• BROYDEN
• NEWTON
To converge design specifications and tear streams:
• BROYDEN
• NEWTON
For optimization:
• SQP
• COMPLEX
Global convergence options can be specified on the Convergence
ConvOptions Defaults form.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 249
©1998 AspenTech. All rights reserved.
Flowsheet Sequence
• To determine the flowsheet sequence calculated by
Aspen Plus, look under the “COMPUTATION ORDER
FOR THE FLOWSHEET” section in the Control Panel, or
on the left-hand pane of the Control Panel window.
• User-determined sequences can be specified on the
Convergence Sequence form.
• User-specified sequences can be either full or partial.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 250
©1998 AspenTech. All rights reserved.
Tear Streams
• Which are the recycle streams?
• Which are the possible tear streams?
S7
S1
B1
MIXER
S2
B2
MIXER
S3
B3
FSPLIT
S4
B4
S5
FSPLIT
S6
• A tear stream is one for which Aspen Plus makes an initial
guess, and iteratively updates the guess until two
consecutive guesses are within a specified tolerance.
• Tear streams are related to, but not the same as recycle
streams.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 251
©1998 AspenTech. All rights reserved.
Tear Streams (Continued)
• To determine the tear streams chosen by Aspen Plus,
look under the “Flowsheet Analysis” section in the Control
Panel.
• User-determined tear streams can be specified on the
Convergence Tear form.
• Providing estimates for tear streams can facilitate or
speed up flowsheet convergence (highly recommended,
otherwise the default is zero).
• If you enter information for a stream that is in a “loop,”
Aspen Plus will automatically try to choose that stream to
be a tear stream.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 252
©1998 AspenTech. All rights reserved.
Reconciling Streams
•
Simulation results for a stream can be copied onto the
its input form.
•
Select a stream on the flowsheet, click the right mouse
button and select “Reconcile” from the list to copy
stream results to the input form.
- Two state variables must be selected for the stream
flash calculation.
- Component flows, or component fractions and total
flow can be copied.
- Mole, mass, or standard liquid volume basis can be
selected.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 253
©1998 AspenTech. All rights reserved.
Convergence Workshop
Objective: Converge this flowsheet.
Start with the file CONVERGE.BKP.
100 lbmol/hr
T=70 F
P=35 psia
50 lbmol/hr Ethylene Glycol
T=165 F
P=15 psia
FEED
XH20
= 0.4
XMethanol = 0.3
XEthanol = 0.3
COLUMN
GLYCOL
DIST
PREHEATR
BOT-COOL
VAPOR
Area = 65 sqft
PREFLASH
FEED-HT
Theoretical Stages = 10
Reflux Ratio = 5
Distillate to Feed Ratio = 0.2
Column Pressure = 1 atm
Feed Stage = 5
Total Condenser
DP=0
Q=0
LIQ
BOT
Use NRTL-RK Property Method
Septiembre 12, 2001
®
Introduction to Aspen Plus
When finished, save as
filename: CONV-R.BKP
Slide 254
©1998 AspenTech. All rights reserved.
Convergence Workshop (Continued)
Hints for Convergence Workshop:
Questions to ask yourself:
- What messages are displayed in the control panel?
- Why do some of the blocks show zero flow?
- What is the Aspen Plus-generated execution sequence for the
flowsheet?
- Which stream does Aspen Plus choose as a tear stream?
- What are other possible tear streams?
Recommendation: Give initial estimates for a tear stream.
- Of the three possible tear streams you could choose, which do
you know the most about? (Note: If you enter information for a
stream that is in a “loop,” Aspen Plus will automatically choose
that stream to be a tear stream and set up a convergence block
for it.)
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 255
©1998 AspenTech. All rights reserved.
Convergence Workshop (Continued)
Questions to ask yourself:
- Does the flowsheet converge after entering initial estimates for
the tear stream?
- If not, why not? (see control panel)
- How is the err/tol value behaving, and what is its value at the
end of the run?
- Does it appear that increasing the number of convergence
iterations will help?
- What else can be tried to improve this convergence?
Recommendation: Try a different convergence algorithm (e.g. Direct,
Broyden, or Newton).
Note: You can either manually create a convergence block to converge
the tear stream of your choice, or you can change the default
convergence method for all tear streams on the Convergence
Conv Options Defaults Default Methods sheet.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 256
©1998 AspenTech. All rights reserved.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 257
©1998 AspenTech. All rights reserved.
Reach Your
True
Potential
Full-Scale Plant Modeling Workshop
Objective:
Practice and apply many of the techniques used in this
course and learn how to best approach modeling
projects
Introduction to Aspen Plus
®
258
©1998 AspenTech. All rights reserved.
Full-Scale Plant Modeling Workshop
Objective: Model a methanol plant.
The process being modeled is a methanol plant. The
basic feed streams to the plant are Natural Gas, Carbon
Dioxide (assumed to be taken from a nearby Ammonia
Plant) and Water. The aim is to achieve the methanol
production rate of approximately 62,000 kg/hr, at a purity
of at least 99.95 % wt.
This is a large flowsheet that would take an experienced
engineer more than an afternoon to complete. Start
building the flowsheet and think about how you would
work to complete the project.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 259
©1998 AspenTech. All rights reserved.
General Guidelines
• Build the flowsheet one section at a time.
• Simplify whenever possible. Complexity can always be
added later.
• Investigate the physical properties.
- Use Analysis.
- Check if binary parameters are available.
- Check for two liquid phases.
- Use an appropriate equation of state for the portions of
the flowsheet involving gases and use an activity
coefficient model for the sections where non-ideal
liquids may be present.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 260
©1998 AspenTech. All rights reserved.
Full-Scale Plant Modeling Workshop
Air
FURNACE
Fuel
MEOHRXR
SYNCOMP
SPLIT1
COOL4
E121
SPLIT2
FL3
COOL2 COOL3
MKUPST
M2 FEEDHTR
FL2
MIX2
COOL1
CIRC
E122
FL4
BOILER FL1
H2OCIRC
REFORMER
CO2 CO2COMP M1
E223
E124
SATURATE
NATGAS
TOPPING
CH4COMP
M4
REFINING
MKWATER
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 261
©1998 AspenTech. All rights reserved.
FL5
Part 1: Front-End Section
From Furnace
MKUPST
M2
FEEDHTR
To BOILER
REFORMER
H2OCIRC
CO2COMP
CO2
NATGAS
Septiembre 12, 2001
®
M1
SATURATE
CH4COMP
Introduction to Aspen Plus
Slide 262
©1998 AspenTech. All rights reserved.
Part 1: Front-End Section (Continued)
1. Front-end Section
Carbon Dioxide Stream – CO2
• Temperature = 43 C
• Pressure = 1.4 bar
• Flow = 24823 kg/hr
• Mole Fraction
- CO2 - 0.9253
- H2 - 0.0094
- H2O - 0.0606
- CH4 - 0.0019
- N2 - 0.0028
Natural Gas Stream - NATGAS
• Temperature = 26 C
• Pressure = 21.7 bar
• Flow = 29952 kg/hr
• Mole Fraction
- CO2 - 0.0059
- CH4 - 0.9539
- N2 - 0.0008
- C2H6 - 0.0391
- C3H8 - 0.0003
Septiembre 12, 2001
®
Circulation Water - H2OCIRC
• Pure water stream
• Flow = 410000 kg/hr
• Temperature = 195 C
• Pressure = 26 bar
Makeup Steam - MKUPST
• Stream of pure steam
• Flow = 40000 kg/hr
• Pressure = 26 bar
• Vapor Fraction = 1
• Adjust the makeup steam flow to achieve a
desired steam to methane molar ratio of 2.8 in
the Reformer feed REFFEED.
Introduction to Aspen Plus
Slide 263
©1998 AspenTech. All rights reserved.
Part 1: Front-End Section (Continued)
Carbon Dioxide Compressor - CO2COMP
• Discharge Pressure = 27.5 bar
• Compressor Type = 2 stage
Natural Gas Compressor - CH4COMP
• Discharge Pressure = 27.5 bar
• Compressor Type = single stage
Reformer Process Side Feed Stream Pre-Heater - FEEDHTR
• Exit Temperature = 560 C
• Pressure drop = 0
Saturation Column - SATURATE
• 1.5 inch metal pall ring packing.
• Estimated HETP = 10 x 1.5 inches = 381 mm
• Height of Packing = 15 meters
• No condenser and no reboiler.
Reformer Reactor - REFORMER
• Consists of two parts: the Furnace portion and the Steam Reforming portion
• Exit Temperature of the Steam Reforming portion = 860 C
• Pressure = 18 bar
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 264
©1998 AspenTech. All rights reserved.
Part 1: Front-End Section Check
Temperature C
Pressure bar
Vapor Frac
Mole Flow kmol/hr
Mass Flow kg/hr
Volume Flow cum/hr
Enthalpy MMkcal/hr
Mole Flow kmol/hr
CO
CO2
H2
WATER
METHANOL
METHANE
NITROGEN
BUTANOL
DME (DIMETHYLETHER)
ACETONE
OXYGEN
ETHANE
PROPANE
Septiembre 12, 2001
®
Reformer Product
860
18
1
10266.6541
139696.964
53937.9538
-213.933793
1381.68394
751.335833
4882.77068
2989.25863
0.000686384
258.513276
3.08402321
0
2.06E-10
2.18E-08
1.80E-15
0.007007476
6.74097E-07
Introduction to Aspen Plus
Slide 265
©1998 AspenTech. All rights reserved.
Part 2: Heat Recovery Section
SYNCOMP
To Methanol Loop
COOL4
FL3
COOL2
COOL3
FL2
COOL1
From Reformer
BOILER
FL1
To REFINING
Septiembre 12, 2001
®
To TOPPING
Introduction to Aspen Plus
Slide 266
©1998 AspenTech. All rights reserved.
Part 2: Heat Recovery Section (Continued)
2. Heat Recovery Section
•
This section consists of a series of heat exchangers and flash vessels used to recover the available
energy and water in the Reformed Gas stream.
BOILER
• Exit temperature = 166 C
• Exit Pressure= 18 bar
FL1
• Pressure Drop = 0 bar
• Heat Duty = 0 MMkcal/hr
COOL1
• Exit temperature = 136 C
• Exit Pressure = 18 bar
FL2
• Exit Pressure = 17.7 bar
• Heat Duty = 0 MMkcal/hr
COOL2
• Exit temperature = 104 C
• Exit Pressure = 17.9 bar
FL3
• Exit Pressure = 17.4 bar
• Heat Duty = 0 MMkcal/hr
COOL3
• Exit temperature = 85 C
• Pressure Drop = 0.1 bar
SYNCOM
• Two Stage Polytropic compressor
• Discharge Pressure = 82.5 bar
• Intercooler Exit Temperature = 40 C
COOL4
• Exit temperature = 40 C
• Exit Pressure = 17.6 bar
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 267
©1998 AspenTech. All rights reserved.
Part 2: Heat Recovery Section Check
Temperature C
Pressure bar
Vapor Frac
Mole Flow kmol/hr
Septiembre 12, 2001
®
To Methanol Loop
40.0
82.50
0.997465769
7302.28917
Introduction to Aspen Plus
Slide 268
©1998 AspenTech. All rights reserved.
Part 3: Methanol Synthesis Section
MEOHRXR
To Furnace
SPLIT1
From SYNCOMP
E121
SPLIT2
MIX2
CIRC
E122
FL4
E223
E124
To FL5
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 269
©1998 AspenTech. All rights reserved.
Part 3: Methanol Synthesis Section (Continued)
3. Methanol Synthesis Loop Section
Methanol Reactor - MEOHRXR
• Tube cooled reactor
• Exit Temperature from the tubes = 240 C
• No pressure drop across the reactor
• Reactions
− CO + H2O <-> CO2 + H2
− CO2 + 3H2 <-> CH3OH + H2O
− 2CH3OH <-> DIMETHYLETHER + H2O
− 4CO + 8H2 <-> N-BUTANOL + 3H2O
− 3CO + 5H2 <-> ACETONE + 2H2O
(Equilibrium)
(+15 C Temperature Approach)
(Molar extent 0.2kmol/hr)
(Molar extent 0.8kmol/hr)
(Molar extent 0.3kmol/hr)
E121
• Exit Temperature - 150 C
• Exit Pressure - 81 bar
FL4
• Exit Pressure = 75.6 bar
• Heat Duty = 0 MMkcal/hr
E122
• Cold Side Exit Temperature - 120 C
CIRC
• Single stage compressor
• Discharge Pressure = 83 bar
• Discharge Temperature = 55 C
E223
• Exit Temperature - 60 C
• Exit Pressure - 77.3 bar
E124
• Exit Temperature - 45 C
• Exit Pressure - 75.6 bar
Septiembre 12, 2001
®
SPLIT1
• Split Fraction = 0.8 to stream to E121
SPLIT2
• Stream PURGE = 9000 kg/hr
• Stream RECYCLE = 326800 kg/hr
Introduction to Aspen Plus
Slide 270
©1998 AspenTech. All rights reserved.
Part 3: Methanol Synthesis Section Check
Temperature C
Pressure bar
Vapor Frac
Mole Flow kmol/hr
Septiembre 12, 2001
®
To FL5
45.0
75.60
0.000
2673.354
Temperature C
Pressure bar
Vapor Frac
Mole Flow kmol/hr
Mass Flow kg/hr
Volume Flow cum/hr
Enthalpy MMkcal/hr
Mole Flow kmol/hr
CO
CO2
H2
WATER
METHANOL
METHANE
NITROGEN
BUTANOL
DME
ACETONE
OXYGEN
ETHANE
PROPANE
Introduction to Aspen Plus
MEOHRXR Product
249.7
83.00
1.000
29091.739
413083.791
15637.807
-559.129
799.563
3137.144
13379.353
644.301
2140.046
8896.430
91.428
0.845
1.864
0.588
0.000
0.177
0.000
Slide 271
©1998 AspenTech. All rights reserved.
Part 4: Distillation Section
To Furnace
From FL4
From COOL1
FL5
From COOL2
TOPPING
REFINING
M4
MKWATER
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 272
©1998 AspenTech. All rights reserved.
Part 4: Distillation Section (Continued)
4. Distillation Section
Makeup Steam - MKWATER
• Stream of pure water
• Flow = 10000 kg/hr
• Pressure = 5 bar
• Temperature = 40 C
• Adjust the make-up water flow (stream MKWATER) to the CRUDE stream to achieve a stream
composition of 23 wt.% of water in the stream feeding the Topping column (stream TOPFEED) to
achieve 100 ppm methanol in the Refining column BTMS stream.
Topping Column - TOPPING
• Number of Stages = 51 (including condenser and reboiler)
• Condenser Type = Partial Vapor/Liquid
• Feed stage = 14
• Distillate has both liquid and vapor streams
• Distillate rate = 1400 kg/hr
• Pressure profile: stage 1 = 1.5 bar and stage 51 = 1.8 bar
• Distillate vapor fraction = 99 mol%
• Stage 2 heat duty = -7 Mmkcal/hr
• Stage 51 heat duty Specified by the heat stream
• Reboiler heat duty is provided via a heat stream from block COOL2
• Boil-up Ratio is approximately 0.52
• Valve trays
• The column has two condensers. To represent the liquid flow connections a pumparound can be
used between stage 1 and 3.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 273
©1998 AspenTech. All rights reserved.
Part 4: Distillation Section (Continued)
Distillation Section (Continued)
Refining Column - REFINING
• Number of Stages = 95 (including condenser and reboiler)
• Condenser Type = Total
• Distillate Rate = 1 kg/hr
• Feed stage = 60
• Liquid Product sidedraw from Stage 4 @ 62000 kg/hr (Stream name – PRODUCT)
• Liquid Product sidedraw from Stage 83 @ 550 kg/hr (Stream name – FUSELOIL)
• Reflux rate = 188765 kg/hr
• Pressure profile: stage 1= 1.5bar and stage 95=2bar
• Reboiler heat duty is provided via a conventional reboiler supplemented by a heat stream from a
heater block to stage 95
• Boil-up Ratio is approximately 4.8
• Valve trays
• To meet environmental regulations, the bottoms stream must contain no more than 100ppm by
weight of methanol as this stream is to be dumped to a nearby river.
FL5
• Exit Pressure
• Heat Duty
5 bar
0 MMkcal/hr
M4
•
For water addition to the crude methanol
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 274
©1998 AspenTech. All rights reserved.
Part 4: Distillation Section Check
Temperature C
Pressure bar
Vapor Frac
Mole Flow kmol/hr
Mass Flow kg/hr
Volume Flow cum/hr
Enthalpy MMkcal/hr
Mole Flow kmol/hr
CO
CO2
H2
WATER
METHANOL
METHANE
NITROGEN
BUTANOL
DME
ACETONE
OXYGEN
ETHANE
PROPANE
TOPFEED
LTENDS
SECPURGE REFINE
PRODUCT BTMS
LIQPURGE FUSELOIL
43.8
33.1
33.1
85.8
75.1
120.1
74.8
90.4
5.00
1.50
1.50
1.80
1.52
2.00
1.50
1.95
0.001
1.000
0.000
0.000
0.000
0.000
0.000
0.000
3029.767
33.807
0.341
2995.618
1928.736
1047.117
0.031
19.733
82623.475
1388.896
11.104
81223.475
61800.974
18871.500
1.000
550.000
111.175
573.782
0.014
107.201
83.975
21.058
0.001
0.722
-186.388
-2.802
-0.020
-178.587
-107.391
-69.633
-0.002
-1.199
0.004
26.537
0.014
1054.851
1945.891
1.267
0.003
0.798
0.116
0.285
0.000
0.000
0.000
Septiembre 12, 2001
®
0.004
26.535
0.014
0.000
5.591
1.267
0.003
0.000
0.116
0.276
0.000
0.000
0.000
0.000
0.002
0.000
0.000
0.334
0.000
0.000
0.000
0.000
0.005
0.000
0.000
0.000
0.000
0.000
0.000
1054.851
1939.966
0.000
0.000
0.798
0.000
0.004
0.000
0.000
0.000
0.000
0.000
0.000
0.000
1928.733
0.000
0.000
0.000
0.000
0.004
0.000
0.000
0.000
Introduction to Aspen Plus
0.000
0.000
0.000
1046.942
0.059
0.000
0.000
0.117
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.031
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
7.910
11.143
0.000
0.000
0.681
0.000
0.000
0.000
0.000
0.000
Slide 275
©1998 AspenTech. All rights reserved.
Part 5: Furnace Section
To REFORMER
From FL5
Air
From SPLIT2
FURNACE
Fuel
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 276
©1998 AspenTech. All rights reserved.
Part 5: Furnace Section (Continued)
5. Furnace Section
Air to Furnace - AIR
• Temperature = 366 C
• Pressure = 1 atm
• Flow = 281946 kg/hr
• Adjust the air flow to achieve 2%(vol.) of oxygen in the FLUEGAS stream.
Fuel to Furnace - FUEL
• Flow = 9436 kg/hr
• Conditions and composition are the same as for the natural gas stream
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 277
©1998 AspenTech. All rights reserved.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 278
©1998 AspenTech. All rights reserved.
Reach Your
True
Potential
Additional Topics
Introduction to Aspen Plus
®
279
©1998 AspenTech. All rights reserved.
Reach Your
True
Potential
Maintaining Aspen Plus Simulations
Objective:
Introduce how to store simulations and retrieve them
from your computer environment
Aspen Plus References:
Introduction
to Aspen
PlusFiles
• User Guide, Chapter 15,
Managing
Your
®
280
©1998 AspenTech. All rights reserved.
File Formats in Aspen Plus
File Type Extension
Format Description
Document
*.apw
Binary
File containing simulation input and results and
intermediate convergence information
Backup
*.bkp
ASCII
Archive file containing simulation input and
results
Template
*.apt
ASCII
Template containing default inputs
Input
*.inp
Text
Simulation input
Run Message *.cpm
Text
Calculation history shown in the Control Panel
History
*.his
Text
Detailed calculation history and diagnostic
messages
Summary
*.sum
ASCII
Simulation results
Problem
Definition
*.appdf
Binary
File containing arrays and intermediate
convergence information used in the simulation
calculations
Report
*.rep
Text
Simulation report
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 281
©1998 AspenTech. All rights reserved.
File Type Characteristics
•
Binary files
- Operating system and version specific
- Not readable, not printable
•
ASCII files
- Transferable between operating systems
- Upwardly compatible
- Contain no control characters, “readable”
- Not intended to be printed
•
Text files
- Transferable between operating systems
- Upwardly compatible
- Readable, can be edited
- Intended to be printed
Septiembre 12, 2001
Introduction to Aspen Plus
®
Slide 282
©1998 AspenTech. All rights reserved.
How to Store a Simulation
Three ways to store simulations:
Document
(*.apw)
Simulation definition Yes
Convergence info
Yes
Results
Yes
Flowsheet Graphics Yes
User readable
No
Open/save speed
High
Space requirements High
Septiembre 12, 2001
®
Backup
(*.bkp)
Yes
No
Yes
Yes
No
Low
Low
Introduction to Aspen Plus
Input
(*.inp)
Yes
No
No
Yes/No
Yes
Lowest
Lowest
Slide 283
©1998 AspenTech. All rights reserved.
Template Files
Template files are used to set your personal preferences:
•
•
•
•
•
•
•
•
•
•
Units of measurement
Property sets for stream reports
Composition basis
Stream report format
Global flow basis for input specifications
Setting Free-Water option
Selection for Stream-Class
Property Method
(Required) Component list
Other application-specific defaults
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 284
©1998 AspenTech. All rights reserved.
How to Create a Personal Template
•
Any flowsheet (complete or incomplete) can be saved
as a template file.
•
In order to have a personal template appear on the
Personal sheet of the New dialog box, simply put the
template file into the AP101\GUI\Templates\Personal
folder.
•
The text on the Setup Specifications Description sheet
will appear in the Preview window when the template
file is selected in the New dialog box.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 285
©1998 AspenTech. All rights reserved.
Maintaining Your Computer
•
•
Aspen Plus 10 runs best on a healthy computer.
Minimum RAM
GUI only
Win 95 and 32 MB
Win 98
Windows NT 64 MB
96 MB
•
Having more is better -- if near minimum, avoid running
too many other programs along with Aspen Plus.
•
Active links increase needed RAM.
Septiembre 12, 2001
®
GUI and
Engine
64 MB
Introduction to Aspen Plus
Slide 286
©1998 AspenTech. All rights reserved.
Maintaining Your Hard Disk
•
Keep plenty of free space on disk used for:
- Your Aspen working directory
- Windows swap files
•
Delete unneeded files:
- Old .appdf, .his, etc.
- Aspen document files (*.apw) that aren’t active
- Aspen temporary files (_4404ydj.appdf, for example)
•
Defragment regularly (once a week), even if Windows
says you don’t need to -- make the free space
contiguous.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 287
©1998 AspenTech. All rights reserved.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 288
©1998 AspenTech. All rights reserved.
Reach Your
True
Potential
Customizing the Look of Your Flowsheet
Objective:
Introduce several ways of annotating your flowsheet to
create informative Process Flow Diagrams
Aspen Plus References:
• User Guide, Chapter 14, Annotating Process Flowsheets
Related Topics:
• User Guide, Chapter 37, Working with Other Windows Programs
Introduction to Aspen Plus
®
289
©1998 AspenTech. All rights reserved.
Customizing the Process Flow Diagram
• Add annotations
-
•
•
•
Text
Graphics
Tables
Add OLE objects
-
Add a titlebox
Add plots or diagrams
Display global data
-
Stream flowrate, pressure and temperature
Heat stream duty and work stream power
Block duty and power
Use PFD mode
-
Change flowsheet connectivity
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 290
©1998 AspenTech. All rights reserved.
Viewing
• Use the View menu to select the elements that you wish
to view:
- PFD Mode
- Global Data
- Annotation
- OLE Objects
• All of the elements can be turned on and off
independently.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 291
©1998 AspenTech. All rights reserved.
Adding Annotation
•
Use the Draw Toolbar to add text and graphics. (Select
Toolbar… from the View menu to select the Draw
Toolbar if it is not visible.)
•
To create a stream table, click on the Stream Table
button on the Results Summary Streams Material
sheet.
•
Annotation objects can be attached to flowsheet
elements such as streams or blocks.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 292
©1998 AspenTech. All rights reserved.
Example of a Stream Table
Heat and Material Balance Table
Stream ID
COOL-OUT
FEED
PRODUCT
REAC-OUT
RECYCLE
Temperature
F
130.0
220.0
130.1
854.7
130.1
Pressure
PSI
14.60
36.00
14.70
14.70
14.70
0.054
1.000
0.000
1.000
1.000
44.342
80.000
41.983
44.342
2.359
Vapor Frac
Mole Flow
LBMOL/HR
Mass Flow
LB/HR
4914.202
4807.771
4807.772
4914.202
106.431
Volume Flow
CUFT/HR
1110.521
15648.095
93.470
42338.408
1003.782
Enthalpy
MMBTU/HR
-0.490
1.980
-0.513
2.003
0.023
Mole Flow
LBMOL/HR
BENZENE
2.033
40.000
1.983
2.033
0.050
PROPYLEN
4.224
40.000
1.983
4.224
2.241
38.017
38.085
0.069
CUMENE
38.085
Mole Frac
BENZENE
0.046
0.500
0.047
0.046
0.021
PROPYLEN
0.095
0.500
0.047
0.095
0.950
CUMENE
0.859
0.906
0.859
0.029
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 293
©1998 AspenTech. All rights reserved.
Adding Global Data
•
On the Results View sheet when selecting Options from
the Tools menu, choose the block and stream results
that you want displayed as Global Data.
•
Check Global Data on the View menu to display the
data on the flowsheet. 130
15
Temperature (F)
106
Pressure (psi)
Flow Rate (lb/hr)
Q
RECYCLE
Duty (Btu/hr)
220
36
4808
REACTOR
855
130
15
15
4914
4914
COOL
FEED
REAC-OUT
Q=0
COOL-OUT
130
SEP
15
4808
Q=-2492499
Q=0
PRODUCT
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 294
©1998 AspenTech. All rights reserved.
Using PFD Mode
•
In this mode, you can add or delete unit operation icons
to the flowsheet for graphical purposes only.
•
Using PFD mode means that you can change flowsheet
connectivity to match that of your plant.
•
PFD-style drawing is completely separate from the
graphical simulation flowsheet. You must return to
simulation mode if you want to make a change to the
actual simulation flowsheet.
•
PFD Mode is indicated by the Aqua border around the
flowsheet.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 295
©1998 AspenTech. All rights reserved.
Examples of When to Use PFD Mode
•
In the simulation flowsheet, it may be necessary to use
more than one unit operation block to model a single
piece of equipment in a plant.
-
•
For example, a reactor with a liquid product and a vent may
need to be modeled using an RStoic reactor and a Flash2
block. In the report, only one unit operation icon is needed to
represent the unit in the plant.
On the other hand, some pieces of equipment may not
need to be explicitly modeled in the simulation
flowsheet.
-
For example, pumps are frequently not modeled in the
simulation flowsheet; the pressure change can be neglected or
included in another unit operation block.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 296
©1998 AspenTech. All rights reserved.
Annotation Workshop
Objective: Use annotation to create a process flow diagram
for the cyclohexane flowsheet
Part A:
Using the cyclohexane production Workshop (saved as
CYCLOHEX.BKP), display all stream and block global data.
Part B:
Add a title to the flowsheet diagram.
Part C:
Add a stream table to the flowsheet diagram.
Part D:
Using PFD Mode, add a pump for the BZIN stream for graphical
purposes only.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 297
©1998 AspenTech. All rights reserved.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 298
©1998 AspenTech. All rights reserved.
Reach Your
True
Potential
Estimation of Physical Properties
Objectives:
Provide an overview of estimating physical property
parameters in Aspen Plus
Aspen Plus References:
• User Guide, Chapter 30, Estimating Property Parameters
• Physical Property Methods and Models Reference Manual,
Chapter 8, Property Parameter
Introduction toEstimation
Aspen Plus
®
299
©1998 AspenTech. All rights reserved.
What is Property Estimation?
• Property Estimation is a system to estimate parameters
required by physical property models. It can be used to
estimate:
- Pure component physical property constants
- Parameters for temperature-dependent models
- Binary interaction parameters for Wilson, NRTL and
UNIQUAC
- Group parameters for UNIFAC
• Estimations are based on group-contribution methods and
corresponding-states correlations.
• Experimental data can be incorporated into estimation.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 300
©1998 AspenTech. All rights reserved.
Using Property Estimation
• Property Estimation can be used in two ways:
- On a stand-alone basis: Property Estimation Run Type
- Within another Run Type: Flowsheet, Property
Analysis, Data Regression, PROPERTIES PLUS or
Assay Data Analysis
• You can use Property Estimation to estimate properties for
both databank and non-databank components.
• Property Estimation information is accessed in the
Properties Estimation folder.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 301
©1998 AspenTech. All rights reserved.
Estimation Methods and Requirements
• User Guide, Chapter 30, Estimating Property Parameters,
has a complete list of properties that can be estimated, as
well as the available estimation methods and their
respective requirements.
• This same information is also available under the on-line
help in the estimation forms.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 302
©1998 AspenTech. All rights reserved.
Steps For Using Property Estimation
1. Define molecular structure on the Properties Molecular
Structure form.
2. Enter any experimental data using Parameters or Data
forms.
- Experimental data such as normal boiling point (TB)
is very important for many estimation methods. It
should be entered whenever possible.
3. Activate Property Estimation and choose property
estimation options on the Properties Estimation Input
form.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 303
©1998 AspenTech. All rights reserved.
Defining Molecular Structure
• Molecular structure is required for all group-contribution
methods used in Property Estimation. You can:
- Define molecular structure in the general format and
allow Aspen Plus to determine functional groups,
or
- Define molecular structure in terms of functional
groups for particular methods
Reference: For a list of available group-contribution method functional
groups, see Aspen Plus Physical Property Data Reference Manual,
Chapter 3, Group Contribution Method Functional Groups.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 304
©1998 AspenTech. All rights reserved.
Steps For Defining General Structure
1. Sketch the structure of the molecule on paper.
2. Assign a number to each atom, omitting hydrogen.
(The numbers must be consecutive starting with 1.)
3. Go to the Properties Molecular Structure Object
Manager, choose the component, and select Edit.
4. On the Molecular Structure General sheet, define the
molecule by its connectivity. Describe two atoms at a
time:
• Specify the types of atoms (C, O, S, …)
• Specify the type of bond that connects the two atoms
(single, double, …)
Note: If the molecule is a non-databank component, on the
Components Specifications form, enter a Component ID,
but do not enter a Component name or Formula.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 305
©1998 AspenTech. All rights reserved.
Example of Defining Molecular Structure
• Example of defining molecular structure for isobutyl
alcohol using the general method
- Sketch the structure of the molecule, and assign a
number to each atom, omitting hydrogen.
C1
C2
C4
O5
C3
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 306
©1998 AspenTech. All rights reserved.
Example of Defining Molecular Structure
• Go to the Properties Molecular Structure Object Manager,
choose the component, and select Edit.
• On Properties Molecular Structure General sheet,
describe molecule by its connectivity, two atoms at a time.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 307
©1998 AspenTech. All rights reserved.
Atom Types
• Current available atom types:
Atom Type
C
O
N
S
B
Si
F
CL
Br
I
Al
Description
Carbon
Oxygen
Nitrogen
Sulfur
Boron
Silicon
Fluorine
Chlorine
Bromine
Iodine
Aluminum
Septiembre 12, 2001
®
Atom Type Description
P
Phosphorous
Zn
Zinc
Ga
Gallium
Ge
Germanium
As
Arsenic
Cd
Cadmium
Sn
Tin
Sb
Antimony
Hg
Mercury
Pb
Lead
Bi
Bismuth
Introduction to Aspen Plus
Slide 308
©1998 AspenTech. All rights reserved.
Bond Types
• Current available bond types:
- Single bond
- Double bond
- Triple bond
- Benzene ring
- Saturated 5-membered ring
- Saturated 6-membered ring
- Saturated 7-membered ring
- Saturated hydrocarbon chain
Note: You must assign consecutive atom numbers to
Benzene ring, Saturated 5-membered ring, Saturated 6membered ring, Saturated 7-membered ring, and
Saturated hydrocarbon chain bonds.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 309
©1998 AspenTech. All rights reserved.
Steps For Using Property Estimation
1. Define molecular structure on the Properties
Molecular Structure form.
2. Enter any experimental data using Parameters or Data
forms.
- Experimental data such as normal boiling point (TB) is
very important for many estimation methods. It should
be entered whenever possible.
3. Activate Property Estimation and choose property
estimation options on the Properties Estimation Input
form.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 310
©1998 AspenTech. All rights reserved.
Example of Entering Additional Data
• The following data was obtained for isobutyl alcohol.
- Normal boiling point (TB) = 107.6 C
- Critical temperature (TC) = 274.6 C
- Critical pressure (PC) = 43 bar
• Enter this data into the simulation to improve the
estimated values.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 311
©1998 AspenTech. All rights reserved.
Example of Entering Additional Data
• Go to the Properties Parameters Pure Component Object
Manager and create a new Scalar parameter form.
• Enter the parameters, the components, and the values.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 312
©1998 AspenTech. All rights reserved.
Steps For Using Property Estimation
1. Define molecular structure on the Properties
Molecular Structure form.
2. Enter any experimental data using Parameters or Data
forms.
- Experimental data such as normal boiling point (TB) is
very important for many estimation methods. It should
be entered whenever possible.
3. Activate Property Estimation and choose property
estimation options on the Properties Estimation Input
form.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 313
©1998 AspenTech. All rights reserved.
Activating Property Estimation
• To turn on Property Estimation, go to the Properties
Estimation Input Setup sheet, and select one of the
following:
- Estimate all missing parameters
Estimates all missing required parameters and any
parameters you may request in the optional Pure
Component, T-Dependent, Binary, and UNIFAC-Group
sheets
- Estimate only the selected parameters
Estimates on the parameter types you select on this
sheet (and then specify on the appropriate additional
sheets)
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 314
©1998 AspenTech. All rights reserved.
Property Estimation Notes
• You can save your property data specifications,
structures, and estimates as backup files, and import
them into other simulations (Flowsheet, Data Regression,
Property Analysis, or Assay Data Analysis Run-Types.)
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 315
©1998 AspenTech. All rights reserved.
Property Estimation Workshop
Objective: Estimate the properties of a dimer,
ethycellosolve.
Ethylcellosolve is not in any of the Aspen Plus databanks.
Use a Run Type of Property Estimation, and estimate the properties for
the new component. (Detailed instructions are included on the following
slide.)
The formula for the component is shown below, along with the normal
boiling point obtained from literature.
Formula:
CH3 - CH2 - O - CH2 - CH2 - O - CH2 - CH2 - OH
TB = 195 C
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 316
©1998 AspenTech. All rights reserved.
Property Estimation Workshop (Continued)
•
•
•
•
•
•
•
•
•
•
•
•
Open a new run, and change the Run Type on the Setup
Specifications Global sheet to Property Estimation.
Enter a new non-databank component as Component ID DIMER, on
the Components Specifications Selection sheet.
On the Properties Molecular Structure Object Manager, select DIMER
and click Edit.
On the General sheet, enter the structure.
Go to the Properties Parameters Pure Component Object Manager
and create a scalar parameter form.
Enter the normal boiling point (TB) of DIMER as 195 C.
Run the estimation, and examine the results.
Note that the results of the estimation are automatically written to
parameters forms, for use in other simulations.
Change the Run Type back to Flowsheet on the Setup Specifications
Global sheet.
Go to the Properties Estimation Input Setup sheet, and choose Do
not estimate any parameters.
Now, it is possible to add a flowsheet and use this component.
Save this file as PCES.BKP.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 317
©1998 AspenTech. All rights reserved.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 318
©1998 AspenTech. All rights reserved.
Reach Your
True
Potential
Electrolytes
Objective:
Introduce the electrolyte capabilities in Aspen Plus
Aspen Plus References:
• User Guide, Chapter 6, Specifying Components
• Physical Property Methods and Models Reference Manual,
Chapter 5, Electrolyte Simulation
Introduction to Aspen Plus
®
319
©1998 AspenTech. All rights reserved.
Electrolytes Examples
• Solutions with acids, bases or salts
• Sour water solutions
• Aqueous amines or hot carbonate for gas sweetening
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 320
©1998 AspenTech. All rights reserved.
Characteristics of an Electrolyte System
• Some molecular species dissociate partially or
completely into ions in a liquid solvent
• Liquid phase reactions are always at chemical
equilibrium
• Presence of ions in the liquid phase requires non-ideal
solution thermodynamics
• Possible salt precipitation
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 321
©1998 AspenTech. All rights reserved.
Types of Components
•
Solvents - Standard molecular species
- Water
- Methanol
- Acetic Acid
•
Soluble Gases - Henry’s Law components
- Nitrogen
- Oxygen
- Carbon Dioxide
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 322
©1998 AspenTech. All rights reserved.
Types of Components (Continued)
•
Ions - Species with a charge
- H3O+
- OH- Na+
- Cl- Fe(CN)63-
•
Salts - Each precipitated salt is a new pure component.
- NaCl(s)
- CaCO3(s)
- CaSO4•2H2O (gypsum)
- Na2CO3•NaHCO3 •2H2O (trona)
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 323
©1998 AspenTech. All rights reserved.
Apparent and True Components
•
True component approach
- Result reported in terms of the ions, salts and
molecular species present after considering solution
chemistry
•
Apparent component approach
- Results reported in terms of base components
present before considering solution chemistry
- Ions and precipitated salts cannot be apparent
components
- Specifications must be made in terms of apparent
components and not in terms of ions or solid salts
» Results are equivalent.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 324
©1998 AspenTech. All rights reserved.
Apparent and True Components Example
•
NaCl in water
- Solution chemistry
• NaCl
• Na+ + Cl-
-->
<-->
Na + + ClNaCl(s)
- Apparent components
• H2O, NaCl
- True components:
• H2O, Na+, Cl-, NaCl(s)
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 325
©1998 AspenTech. All rights reserved.
Electrolyte Wizard
•
•
Generates new components (ions and solid salts)
•
•
•
•
Generates reactions among components
Revises the Pure component databank search order so
that the first databank searched is now ASPENPCD.
Sets the Property method to ELECNRTL
Creates a Henry’s Component list
Retrieves parameters for
- Reaction equilibrium constant values
- Salt solubility parameters
- ELECNRTL interaction parameters
- Henry’s constant correlation parameters
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 326
©1998 AspenTech. All rights reserved.
Electrolyte Wizard (Continued)
•
Generated chemistry can be modified. Simplifying the
Chemistry can make the simulation more robust and
decrease execution time.
» Note:
It is the user’s responsibility to ensure that the
Chemistry is representative of the actual chemical
system.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 327
©1998 AspenTech. All rights reserved.
Simplifying the Chemistry
•
Typical modifications include:
- Adding to the list of Henry’s components
- Eliminating irrelevant salt precipitation reactions
- Eliminating irrelevant species
- Adding species and/or reactions that are not in the
electrolytes expert system database
- Eliminating irrelevant equilibrium reactions
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 328
©1998 AspenTech. All rights reserved.
Limitations of Electrolytes
•
Restrictions using the True component approach:
- Liquid-liquid equilibrium cannot be calculated.
- The following models may not be used:
• Equilibrium reactors:
• Kinetic reactors:
• Shortcut distillation:
• Rigorous distillation:
Septiembre 12, 2001
®
RGibbs and REquil
RPlug, RCSTR, and RBatch
Distl, DSTWU and SCFrac
MultiFrac and PetroFrac
Introduction to Aspen Plus
Slide 329
©1998 AspenTech. All rights reserved.
Limitations of Electrolytes (Continued)
•
Restrictions using the Apparent component approach:
- Chemistry may not contain any volatile species on
the right side of the reactions.
- Chemistry for liquid-liquid equilibrium may not
contain dissociation reactions.
- Input specification cannot be in terms of ions or solid
salts.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 330
©1998 AspenTech. All rights reserved.
Electrolyte Demonstration
Objective: Create a flowsheet using electrolytes.
Create a simple flowsheet to mix and flash two feed streams containing
aqueous electrolytes. Use the Electrolyte Wizard to generate the
Chemistry.
Temp = 25 C
Pres = 1 bar
10 kmol/hr H2O
Filename: ELEC1.BKP
1 kmol/hr HCl
HCL
VAPOR
MIX
NAOH
Temp = 25 C
Pres = 1 bar
10 kmol/hr H2O
1.1 kmol/hr NaOH
Septiembre 12, 2001
®
MIXED
MIXER
FLASH
FLASH2
Isobaric
Molar vapor fraction = 0.75
P-drop = 0
Adiabatic
LIQUID
Introduction to Aspen Plus
Slide 331
©1998 AspenTech. All rights reserved.
Steps for Using Electrolytes
1. Specify the possible apparent components on the
Components Specifications Selection sheet.
2. Click on the Elec Wizard button to generate components
and reactions for electrolyte systems. There are 4 steps:
-
Step 1: Define base components and select reaction
generation options.
Step 2: Remove any undesired species or reactions from
the generated list.
Step 3: Select simulation approach for electrolyte
calculations.
Step 4: Review physical properties specifications and
modify the generated Henry components list and reactions.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 332
©1998 AspenTech. All rights reserved.
Electrolyte Workshop
Objective: Create a flowsheet using electrolytes.
Create a simple flowsheet to model the treatment of a sulfuric acid
waste water stream using lime (Calcium Hydroxide). Use the Electrolyte
Wizard to generate the Chemistry. Use the true component approach.
Temperature = 25C
Pressure = 1 bar
Flowrate = 10 kmol/hr
5 mole% sulfuric acid solution
Note: Remove from the chemistry:
CaSO 4(s)
CaSO 4•1:2W:A(s)
WASTEWAT
B1
LIQUID
LIME
Temperature = 25C
Temperature = 25C
P-drop = 0
Pressure = 1 bar
Flowrate = 10 kmol/hr
5 mole% lime (calcium hydroxide) solution
Septiembre 12, 2001
®
Introduction to Aspen Plus
When finished, save as
filename: ELEC.BKP
Slide 333
©1998 AspenTech. All rights reserved.
Sour Water Stripper Workshop
Saturated vapor
Above stage 3
P = 15 psia
10,000 lbs/hr
VAPOR
SOURWAT
Mass fractions:
H2O
0.997
NH3
0.001
H2S
0.001
CO2
0.001
B1
Theoretical trays: 9
(does not include condenser)
Partial condenser
Reflux Ratio (Molar): 25
No reboiler
STEAM
On stage 10
P = 15 psia
Vapor frac = 1
2,000 lbs/hr
Septiembre 12, 2001
®
BOTTOMS
Introduction to Aspen Plus
Slide 334
©1998 AspenTech. All rights reserved.
Sour Water Stripper Workshop (Continued)
1. Open a new Electrolytes with English units flowsheet.
2. After drawing the flowsheet and entering the necessary
components, generate the electrolytes using the
Electrolytes Wizard. Select the apparent approach and
remove all solid salts used in the generated reactions.
Question: Why aren’t the ionic species’ compositions
displayed on the results forms? How can they be added?
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 335
©1998 AspenTech. All rights reserved.
Sour Water Stripper Workshop (Continued)
3. Add a sensitivity analysis
a) Vary the steam flow rate and tabulate the ammonia
concentration in the bottoms stream. The target is
50 ppm.
b) Vary the column reflux ratio and observe the
condenser temperature. The target is 190 F.
4. Create design specifications
a) After hiding the sensitivity blocks, solve the column with
two design specifications. Use the targets and variables
from part 3.
Save as: SOURWAT.BKP
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 336
©1998 AspenTech. All rights reserved.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 337
©1998 AspenTech. All rights reserved.
Reach Your
True
Potential
Solids Handling
Objective:
Provide an overview of the solid handling capabilities
Aspen Plus References:
• User Guide, Chapter 6, Specifying Components
• Physical Property Methods and Models Reference Manual,
Chapter 3, Property Model
Descriptions
Introduction
to Aspen Plus
®
338
©1998 AspenTech. All rights reserved.
Classes of Components
• Conventional Components
- Vapor and liquid components
- Solid salts in solution chemistry
• Conventional Inert Solids (CI Solids)
- Solids that are inert to phase equilibrium and salt
precipitation/solubility
• Nonconventional Solids (NC Solids)
- Heterogeneous substances inert to phase, salt, and
chemical equilibrium that cannot be represented with
a molecular structure
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 339
©1998 AspenTech. All rights reserved.
Specifying Component Type
•
When specifying components on the Components
Specifications Selection sheet, choose the appropriate
component type in the Type column.
- Conventional - Conventional Components
- Solid - Conventional Inert Solids
- Nonconventional - Nonconventional Solids
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 340
©1998 AspenTech. All rights reserved.
Conventional Components
•
Components participate in vapor and liquid equilibrium
along with salt and chemical equilibrium.
•
Components have a molecular weight.
ð e.g. water, nitrogen, oxygen, sodium chloride, sodium
ions, chloride ions
ð Located in the MIXED substream
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 341
©1998 AspenTech. All rights reserved.
Conventional Inert Solids (CI Solids)
•
Components are inert to phase equilibrium and salt
precipitation/solubility.
•
Chemical equilibrium and reaction with conventional
components is possible.
•
Components have a molecular weight.
ð e.g. carbon, sulfur
ð Located in the CISOLID substream
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 342
©1998 AspenTech. All rights reserved.
Nonconventional Solids (NC Solids)
• Components are inert to phase, salt or chemical
equilibrium.
• Chemical reaction with conventional and CI Solid
components is possible.
• Components are heterogeneous substances and do not
have a molecular weight.
ðe.g. coal, char, ash, wood pulp
ðLocated in the NC Solid substream
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 343
©1998 AspenTech. All rights reserved.
Component Attributes
• Component attributes typically represent the
composition of a component in terms of some set of
identifiable constituents
• Component attributes can be
- Assigned by the user
- Initialized in streams
- Modified in unit operation models
• Component attributes are carried in the material stream.
• Properties of nonconventional components are
calculated by the physical property system using
component attributes.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 344
©1998 AspenTech. All rights reserved.
Component Attribute Descriptions
Attribute Type
Elements
Description
PROXANAL
1. Moisture
2. Fixed Carbon
3. Volatile Matter
4. Ash
Proximate analysis, weight %dry
basis
ULTANAL
1. Ash
2. Carbon
3. Hydrogen
4. Nitrogen
5. Chlorine
6. Sulfur
7. Oxygen
Ultimate analysis, weight % dry
basis
SULFANAL
1. Pyritic
2. Sulfate
3. Organic
Forms of sulfur analysis, weight %
of original coal, dry basis
GENANAL
1. Constituent 1
2. Constituent 2
:
20. Constituent 20
General constituent analysis, weight
or volume %
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 345
©1998 AspenTech. All rights reserved.
Solid Properties
•
For conventional components and conventional solids
- Enthalpy, entropy, free energy and molar volume are
computed.
- Property models in the Property Method specified on
the Properties Specification Global sheet are used.
•
For nonconventional solids
- Enthalpy and mass density are computed.
- Property models are specified on the Properties
Advanced NC-Props form.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 346
©1998 AspenTech. All rights reserved.
Solids Properties - Conventional Solids
For Enthalpy, Free Energy, Entropy and Heat Capacity
• Barin Equations
- Single parameter set for all properties
- Multiple parameter sets may be available for
selected temperature ranges
- List INORGANIC databank before SOLIDS
•
Conventional Equations
- Combines heat of formation and free energies of
formation with heat capacity models
- Aspen Plus and DIPPR model parameters
- List SOLIDS databank before INORGANIC
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 347
©1998 AspenTech. All rights reserved.
Solids Properties - Conventional Solids
•
Solid Heat Capacity
- Heat capacity polynomial model
2
C oS
p = C1 + C2T + C3T +
C4 C5 C6
+
+
T T 2 T3
- Used to calculate enthalpy, entropy and free energy
- Parameter name: CPSP01
•
Solid Molar Volume
- Volume polynomial model
V S = C1 + C2T + C3T 2 + C4T 3 + C5T 4
- Used to calculate density
- Parameter name: VSPOLY
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 348
©1998 AspenTech. All rights reserved.
Solids Properties - Nonconventional Solids
•
Enthalpy
- General heat capacity polynomial model: ENTHGEN
- Uses a mass fraction weighted average
- Based on the GENANAL attribute
- Parameter name: HCGEN
•
Density
- General density polynomial model: DNSTYGEN
- Uses a mass fraction weighted average
- Based on the GENANAL attribute
- Parameter name: DENGEN
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 349
©1998 AspenTech. All rights reserved.
Solids Properties - Special Models for Coal
•
Enthalpy
- Coal enthalpy model: HCOALGEN
- Based on the ULTANAL, PROXANAL and
SULFANAL attributes
•
Density
- Coal density model: DCOALIGT
- Based on the ULTANAL and SULFANAL attributes
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 350
©1998 AspenTech. All rights reserved.
Built-in Material Stream Classes
Stream Class
Description
CONVEN*
Conventional components only
MIXNC
Conventional and nonconventional solids
MIXCISLD
Conventional components and inert solids
MIXNCPSD
Conventional components and nonconventional
solids with particle size distribution
MIXCIPSD
Conventional components and inert solids with
particle size distribution
MIXCINC
Conventional components and inert solids and
nonconventional solids
MIXCINCPSD
Conventional components and nonconventional
solids with particle size distribution
* system default
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 351
©1998 AspenTech. All rights reserved.
Unit Operation Models
•
General Principles
- Material streams of any class are accepted.
- The same stream class should be used for inlet and
-
outlet streams (exceptions: Mixer and ClChng).
Attributes (components or substream) not recognized
are passed unaltered through the block.
Some models allow specifications for each substream
present (examples: Sep, RStoic).
In vapor-liquid separation, solids leave with the liquid.
Unless otherwise specified, outlet solid substreams
are in thermal equilibrium with the MIXED substream.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 352
©1998 AspenTech. All rights reserved.
Solids Workshop 1
Objective: Model a conventional solids dryer.
Dry SiO2 from a water content of 0.5% to 0.1% using air.
Notes: Change the Stream class type to: MIXCISLD.
Put the SiO2 in the CISOLID substream.
The pressure and temperature has to be the same in all the
sub-streams of a stream.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 353
©1998 AspenTech. All rights reserved.
Solids Workshop 1 (Continued)
Temp = 190 F
Pres = 14.7 psia
Flow = 1 lbmol/hr
0.79 mole% N2
0.21 mole% O2
AIR-OUT
Design specification:
Vary the air flow rate
from 1 to 10 lbmol/hr to
achieve 99.9 wt.% SiO2
[SiO2/(SiO2 +Mixed)]
AIR
DRYER
WET
Temp = 70 F
Pres = 14.7 psia
FLASH2
DRY
Pressure Drop = 0
Adiabatic
995 lb/hr SiO2
5 lb/hr H 2O
Use the SOLIDS Property Method
Septiembre 12, 2001
®
Introduction to Aspen Plus
When finished, save as
filename: SOLIDWK1.BKP
Slide 354
©1998 AspenTech. All rights reserved.
Solids Workshop 2
Objective: Use the solids unit operations to model the
particulate removal from a feed of gasifier off gases.
The processing of gases containing small quantities of particulate
materials is rendered difficult by the tendency of the particulates to
interfere with most operations (e.g., surface erosion, fouling, plugging of
orifices and packing). It is therefore necessary to remove most of the
particulate materials from the gaseous stream. Various options are
available for this purpose (Cyclone, Bag-filter, Venturi-scrubber, and an
Electrostatic precipitator) and their particulate separation efficiency can
be changed by varying their design and operating conditions. The final
choice of equipment is a balance between the technical performance
and the cost associated with using a particular unit.
In this workshop, various options for removing particulates from the
syngas obtained by coal gasification are compared.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 355
©1998 AspenTech. All rights reserved.
Solids Workshop 2 (Continued)
G-CYC
Temp = 650 C
Pres = 1 bar
Gas Flowrate = 1000 kmol/hr
Ash Flowrate = 200 kg/hr
Composition (mole-frac)
CO
0.19
CO2
0.20
H2
0.05
H2S
0.02
O2
0.03
CH4
0.01
H2O
0.05
N2
0.35
SO2
0.10
F-CYC
Temp = 40 C
S-CYC
Pres = 1 bar
Water Flowrate = 700 kg/hr
G-SCRUB
F-SCRUB
DUPL
S-SCRUB
FEED
Particle size distribution (PSD)
Size limit
wt. %
[mu]
0- 44
30
44- 63
10
63-90
20
90-130
15
130-200
10
200-280
15
Septiembre 12, 2001
®
Design Mode
Separation Efficiency = 0.9
LIQ
V-SCRUB
G-ESP
F-ESP
When finished, save as
filename: SOLIDWK2.BKP
Design Mode
High Efficiency
Separation Efficiency = 0.9
CYC
Design Mode
Separation Efficiency = 0.9
Dielectric constant = 1.5
F-BF
ESP
S-ESP
G-BF
Design Mode
Max. Pres. Drop = 0.048 bar
FAB-FILT
Introduction to Aspen Plus
S-BF
Slide 356
©1998 AspenTech. All rights reserved.
Solids Workshop 2 (Continued)
•
Coal ash is mainly clay and heavy metal oxides and
can be considered a non-conventional component.
•
HCOALGEN and DCOALIGT can be used to calculate
the enthalpy and material density of ash using the
ultimate, proximate, and sulfur analyses (ULTANAL,
PROXANAL, SULFANAL). These are specified on the
Properties Advanced NC-Props form.
•
Component attributes (ULTANAL, PROXANAL,
SULFANAL) are specified on the Stream Input form.
For ash, zero all non-ash attributes.
•
The PSD limits can be changed on the Setup
Substreams PSD form.
•
Use the IDEAL Property Method.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 357
©1998 AspenTech. All rights reserved.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 358
©1998 AspenTech. All rights reserved.
Reach Your
True
Potential
Optimization
Objective:
Introduce the optimization capability in Aspen Plus
Aspen Plus References:
• User Guide, Chapter 22, Optimization
Related Topics:
• User Guide, Chapter 17, Convergence
• User Guide, Chapter 18,Introduction
Accessing
Flowsheet Variables
to Aspen Plus
®
359
©1998 AspenTech. All rights reserved.
Optimization
• Used to maximize/minimize an objective function
• Objective function is expressed in terms of flowsheet
variables and In-Line Fortran.
• Optimization can have zero or more constraints.
• Constraints can be equalities or inequalities.
• Optimization is located under /Data/Model Analysis
Tools/Optimization
• Constraint specification is under /Data/Model Analysis
Tools/Constraint
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 360
©1998 AspenTech. All rights reserved.
Optimization Example
REACTOR
A, B
A + B --> C + D + E
FEED
Desired Product C
By-product D
Waste Product E
$ 1.30 / lb
$ 0.11 / lb
$ - 0.20 /lb
A, B, C, D, E
PRODUCT
For an existing reactor, find the reactor temperature and
inlet amount of reactant A that maximizes the profit from this
reactor. The reactor can only handle a maximum cooling
load of Q.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 361
©1998 AspenTech. All rights reserved.
Optimization Example (Continued)
• What are the measured (sampled) variables?
- Outlet flowrates of components C, D, E
• What is the objective function to be maximized?
- 1.30*(lb/hr C) + 0.11*(lb/hr D) - 0.20*(lb/hr E)
• What is the constraint?
- The calculated duty of the reactor can not exceed Q.
• What are the manipulated (varied) variables?
- Reactor temperature
- Inlet amount of reactant A
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 362
©1998 AspenTech. All rights reserved.
Steps for Using Optimization
1. Identify measured (sampled) variables.
- These are the flowsheet variables used to calculate
the objective function (Optimization Define sheet).
2. Specify objective function (expression).
- This is the Fortran expression that will be maximized
or minimized (Optimization Objective & Constraints
sheet).
3. Specify maximization or minimization of objective
function (Optimization Objective & Constraints sheet).
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 363
©1998 AspenTech. All rights reserved.
Steps for Using Optimization (Continued)
4. Specify constraints (optional).
- These are the constraints used during the optimization
(Optimization Objective & Constraints sheet).
5. Specify manipulated (varied) variables.
- These are the variables that the optimization block will
change to maximize/minimize the objective function
(Optimization Vary sheet).
6. Specify bounds for manipulated (varied) variables.
- These are the lower and upper bounds within which to
vary the manipulated variable (Optimization Vary
sheet).
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 364
©1998 AspenTech. All rights reserved.
Notes
1. The convergence of the optimization can be sensitive to
the initial values of the manipulated variables.
2. It is best if the objective, the constraints, and the
manipulated variables are in the range of 1 to 100. This
can be accomplished by simply multiplying or dividing
the function.
3. The optimization algorithm only finds local maxima and
minima in the objective function. It is theoretically
possible to obtain a different maximum/minimum in the
objective function, in some cases, by starting at a
different point in the solution space.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 365
©1998 AspenTech. All rights reserved.
Notes (Continued)
4. Equality constraints within an optimization are similar to
design specifications.
5. If an optimization does not converge, run sensitivity
studies with the same manipulated variables as the
optimization, to ensure that the objective function is not
discontinuous with respect to any of the manipulated
variables.
6. Optimization blocks also have convergence blocks
associated with them. Any general techniques used with
convergence blocks can be used if the optimization does
not converge.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 366
©1998 AspenTech. All rights reserved.
Optimization Workshop
Objective: Optimize steam usage for a process.
The flowsheet shown below is part of a Dichloro-Methane solvent
recovery system. The two flashes, TOWER1 and TOWER2, are run
adiabatically at 19.7 and 18.7 psia respectively. The stream FEED
contains 1400 lb/hr of Dichloro-Methane and 98600 lb/hr of water at
100oF and 24 psia. Set up the simulation as shown below, and minimize
the total usage of steam in streams STEAM1 and STEAM2, both of
which contain saturated steam at 200 psia. The maximum allowable
concentration of Dichloro-Methane in the stream EFFLUENT from
TOWER2 is 150 ppm (mass) to within a tolerance of a tenth of a ppm.
Use the NRTL Property Method. Use bounds of 1000 lb/hr to 20,000
lb/hr for the flowrate of the two steam streams. Make sure stream flows
are reported in mass flow and mass fraction units before running. Refer
to the Notes slides for some hints on the previous page if there are
problems converging the optimization.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 367
©1998 AspenTech. All rights reserved.
Optimization Workshop (Continued)
TOP1
STEAM1
TOWER1
FEED
TOP2
BOT1
TOWER2
STEAM2
EFFLUENT
When finished, save as
filename: OPT.BKP
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 368
©1998 AspenTech. All rights reserved.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 369
©1998 AspenTech. All rights reserved.
Reach Your
True
Potential
RadFrac Convergence
Objective:
Introduce the convergence algorithms and initialization
strategies available in RadFrac
Aspen Plus References:
• Unit Operation Models Reference Manual, Chapter 4, Columns
Introduction to Aspen Plus
®
370
©1998 AspenTech. All rights reserved.
RadFrac Convergence Methods
RadFrac provides a variety of convergence methods for
solving separation problems. Each convergence method
represents a convergence algorithm and an initialization
method. The following convergence methods are available:
•
•
•
•
•
•
Standard (default)
Petroleum / Wide-Boiling
Strongly non-ideal liquid
Azeotropic
Cryogenic
Custom
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 371
©1998 AspenTech. All rights reserved.
Convergence Methods (Continued)
Method
Algorithm
Initialization
Standard
Standard
Standard
Petroleum / Wide-boiling
Sum-Rates
Standard
Strongly non-ideal liquid
Nonideal
Standard
Azeotropic
Newton
Azeotropic
Cryogenic
Standard
Cryogenic
Custom
select any
select any
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 372
©1998 AspenTech. All rights reserved.
RadFrac Convergence Algorithms
RadFrac provides four convergence algorithms:
•
•
•
•
Standard (with Absorber=Yes or No)
Sum-Rates
Nonideal
Newton
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 373
©1998 AspenTech. All rights reserved.
Standard Algorithm
The Standard (default, Absorber=No) algorithm:
•
•
•
•
Uses the original inside-out formulation
Is effective and fast for most problems
Solves design specifications in a middle loop
May have difficulties with extremely wide-boiling or
highly non-ideal mixtures
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 374
©1998 AspenTech. All rights reserved.
Standard Algorithm (Continued)
The Standard algorithm with Absorber=Yes:
•
Uses a modified formulation similar to the classical
sum-rates algorithm
•
•
•
•
Applies to absorbers and strippers only
Has fast convergence
Solves design specifications in a middle loop
May have difficulties with highly non-ideal mixtures
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 375
©1998 AspenTech. All rights reserved.
Sum-Rates Algorithm
The Sum-Rates algorithm:
•
Uses a modified formulation similar to the classical
sum-rates algorithm
•
Solves design specifications simultaneously with the
column-describing equations
•
Is effective and fast for wide boiling mixtures and
problems with many design specifications
•
May have difficulties with highly non-ideal mixtures
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 376
©1998 AspenTech. All rights reserved.
Nonideal Algorithm
The Nonideal algorithm:
•
Includes a composition dependency in the local
physical property models
•
•
•
Uses the continuation convergence method
Solves design specifications in a middle loop
Is effective for non-ideal problems
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 377
©1998 AspenTech. All rights reserved.
Newton Algorithm
The Newton algorithm:
•
•
•
Is a classic implementation of the Newton method
•
Can solve design specifications simultaneously or in an
outer loop
•
Handles non-ideality well, with excellent convergence in
the vicinity of the solution
•
Is recommended for azeotropic distillation columns
Solves all column-describing equations simultaneously
Uses the dogleg strategy of Powell to stabilize
convergence
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 378
©1998 AspenTech. All rights reserved.
Vapor-Liquid-Liquid Calculations
You can use the Standard, Newton and Nonideal
algorithms for 3-phase Vapor-Liquid-Liquid systems.
On the RadFrac Setup Configuration sheet, select
Vapor-Liquid-Liquid in the Valid Phases field.
Vapor-Liquid-Liquid calculations:
• Handle column calculations involving two liquid phases
rigorously
• Handle decanters
• Solve design specifications using:
- Either the simultaneous (default) loop or the middle
loop approach for the Newton algorithm
- The middle loop approach for all other algorithms
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 379
©1998 AspenTech. All rights reserved.
Convergence Method Selection
For Vapor-Liquid systems, start with the Standard
convergence method. If the Standard method fails:
• Use the Petroleum / Wide Boiling method if the mixture
is very wide-boiling.
• Use the Custom method and change Absorber to Yes
on the RadFrac Convergence Algorithm sheet, if the
column is an absorber or a stripper.
• Use the Strongly non-ideal liquid method if the mixture
is highly non-ideal.
• Use the Azeotropic method for azeotropic distillation
problems with multiple solutions possible. The
Azeotropic algorithm is also another alternative for
highly non-ideal systems.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 380
©1998 AspenTech. All rights reserved.
Convergence Method Selection (Continued)
For Vapor-Liquid-Liquid systems:
•
Start by selecting Vapor-Liquid-Liquid in the Valid
Phases field of the RadFrac Setup Configuration sheet
and use the Standard convergence method.
•
If the Standard method fails, try the Custom method
with the Nonideal or the Newton algorithm.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 381
©1998 AspenTech. All rights reserved.
RadFrac Initialization Method
Standard is the default Initialization method for RadFrac.
This method:
•
Performs flash calculations on composite feed to obtain
average vapor and liquid compositions
•
•
Assumes a constant composition profile
Estimates temperature profiles based on bubble and
dew point temperatures of composite feed
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 382
©1998 AspenTech. All rights reserved.
Specialized Initialization Methods
Four specialized Initialization methods are available.
Use:
For:
Crude
Wide boiling systems with
multi-draw columns
Chemical
Narrow boiling chemical systems
Azeotropic
Azeotropic distillation columns
Cryogenic
Cryogenic applications
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 383
©1998 AspenTech. All rights reserved.
Estimates
RadFrac does not usually require estimates for
temperature, flow and composition profiles.
RadFrac may require:
•
Temperature estimates as a first trial in case of
convergence problems
•
Liquid and/or vapor flow estimates for the separation of
wide boiling mixtures.
•
Composition estimates for highly non-ideal, extremely
wide-boiling (for example, hydrogen-rich), azeotropic
distillation or vapor-liquid-liquid systems.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 384
©1998 AspenTech. All rights reserved.
Composition Estimates
The following example illustrates the need for composition
estimates in an extremely wide-boiling point system:
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 385
©1998 AspenTech. All rights reserved.
RadFrac Convergence Workshop
Objective: Apply the convergence hints explained in this
section.
HCl column in a VCM production plant
•
Feed
- 130000 kg/hr at 50C, 18 bar
- 19.5%wt HCl, 33.5%wt VCM, 47%wt EDC
- (VCM : vinyl-chloride, EDC : 1,2-dichloroethane)
•
Column
- 33 theoretical stages
- partial condenser (vapor distillate)
- kettle reboiler
- pressure : top 17.88 bar, bottom 18.24 bar
- feed on stage 17
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 386
©1998 AspenTech. All rights reserved.
RadFrac Convergence Workshop (Continued)
First Step:
Specify the column.
-
Set the distillate flow rate to be equal to the mass flow rate of
HCl in the feed.
Specify that the mass reflux ratio is 0.7.
Use Peng-Robinson equation of state (PENG-ROB).
» Question: How should these specifications be implemented?
Note:
Look at the results.
-
Temperature profile
Composition profile
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 387
©1998 AspenTech. All rights reserved.
RadFrac Convergence Workshop (Continued)
Second step:
VCM in distillate and HCl in bottom are much too high!
-
Allow only 5 ppm of HCl in the residue and 10 ppm VCM in the
distillate.
» Question: How should these specifications be implemented?
Note:
You may have some convergence difficulties.
-
Apply the guidelines presented in this section
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 388
©1998 AspenTech. All rights reserved.
RadFrac Convergence Workshop (Continued)
Use the PENG-ROB Property method
flow : HCl in feed
130000 kg/h
50 C, 18 bar,
HCl
19.5%wt
VCM
33.5%wt
EDC
47.0%wt
max 10 ppm VCM
DIST
17.88 bar
COL
mass reflux ratio:0.7
FEED
feed on stage 17
BOT
18.24 bar
max 5 ppm HCl
When finished, save as filename: VCMHCL1.BKP (step 1) and VCMHCL2.BKP (step 2)
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 389
©1998 AspenTech. All rights reserved.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 390
©1998 AspenTech. All rights reserved.
Reach Your
True
Potential
Vinyl Chloride Monomer (VCM) Workshop
Introduction to Aspen Plus
®
391
©1998 AspenTech. All rights reserved.
VCM Workshop
Objective: Set up a flowsheet of a VCM process using the
tools learned in the course.
Vinyl chloride monomer (VCM) is produced through a high pressure,
non-catalytic process involving the pyrolysis of 1,2-dichloroethane
(EDC) according to the following reaction
CH2Cl-CH2Cl
HCl + CHCl=CH2
The cracking of EDC occurs at 500 C and 30 bar in a direct fired
furnace. 1000 kmol/hr of pure EDC feed enters the reactor at 20 C and
30 bar. EDC conversion in the reactor is maintained at 55%. The hot
gases from the reactor are subcooled by 10 degrees before
fractionation.
Two distillation columns are used for the purification of the VCM
product. In the first column, anhydrous HCl is removed overhead and
sent to the oxy chlorination unit. In the second column, VCM product is
removed overhead and the bottoms stream containing unreacted EDC
is recycled back to the furnace. Overheads from both columns are
removed as saturated liquids. The HCL column is run at 25 bar and the
VCM column is run at 8 bar. Use the RK-SOAVE Property Method.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 392
©1998 AspenTech. All rights reserved.
VCM Workshop (Continued)
CH2Cl-CH2Cl
HCl + CHCl=CH2
EDC
1000 kmol/hr EDC
20C
30 bar
HCl
FEED
RStoic Model
VCM
RadFrac Model
Heater Model
REACTOUT
RadFrac Model
HCLOUT
COL1
COOLOUT
VCMOUT
CRACK
RECYCIN
Pump Model
500 C
30 bar
EDC Conv. = 55%
QUENCH
10 deg C subcooling
0.5 bar pressure drop
COL2
VCMIN
15 stages
Reflux ratio = 1.082
Distillate to feed ratio = 0.354
Feed enters above stage 8
Column pressure = 25 bar
PUMP
30 bar outlet pressure
10 stages
Reflux ratio = 0.969
Distillate to feed ratio = 0.550
Feed enters above stage 7
Column pressure = 8 bar
RECYCLE
When finished, save as
filename: VCM.BKP
Use RK-SOAVE property method
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 393
©1998 AspenTech. All rights reserved.
VCM Workshop (Continued)
Part A:
With the help of the process flow diagram on the previous page, set up a
flowsheet to simulate the VCM process. What are the values of the following
quantities?
1. Furnace heat duty
________
2. Quench cooling duty
________
3. Quench outlet temperature
________
4. Condenser and Reboiler duties for COL2
________
________
5. Concentration of VCM in the product stream
________
Part B:
The conversion of EDC to VCM in the furnace varies between 50% and 55%.
Use the sensitivity analysis capability to generate plots of the furnace heat duty
and quench cooling duty as a function of EDC conversion.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 394
©1998 AspenTech. All rights reserved.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 395
©1998 AspenTech. All rights reserved.
Reach Your
True
Potential
ActiveX Automation
Objective:
Introduce ActiveX Automation Capabilities in Aspen Plus
Aspen Plus References:
• User Guide, Chapter 38, Using the Aspen Plus ActiveX Automation
Server
Introduction to Aspen Plus
®
396
©1998 AspenTech. All rights reserved.
Windows Interoperability
•
Three Levels
- Copy/Paste
- Object Linking and Embedding (OLE)
- ActiveX Server
•
Third level is programming against the software using a
macro language. The language demonstrated is Visual
Basic for Applications using Excel97 as the interface.
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 397
©1998 AspenTech. All rights reserved.
Capabilities of Automation
•
Cannot
- Add Streams
- Add Unit Operation Blocks
- Manipulate Flowsheet Graphics
•
Can
- Change Input Specifications
- Read Output Results
- Perform Run Control
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 398
©1998 AspenTech. All rights reserved.
Aspen Plus Simulation File
•
Cannot use Automation to Add Blocks/Streams so
starting point must be an existing Aspen Plus
Simulation file
•
Can use any of the following file types
- *.apw Aspen Plus Document
- *.bkp Aspen Plus Backup File
- *.inp Aspen Plus Input File
- *.apt Aspen Plus Template
•
For this demonstration, load pfdtut.bkp, Reinitialize,
then SaveAs... ActiveXDemo1.bkp
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 399
©1998 AspenTech. All rights reserved.
Automation Demonstration 1
•
Objective: Create an Excel Workbook that performs
the following
- Open Aspen Plus Simulation
- Close Aspen Plus Simulation
- Run Simulation
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 400
©1998 AspenTech. All rights reserved.
Steps to Create Workbook
•
Open Excel
- Setup Excel for VBA Programming
- Select Reference to Aspen Plus
•
•
•
•
Place/Modify Controls
Add Additional Text to Workbook
Program General Declarations
Write Code into Subroutines and Control Events
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 401
©1998 AspenTech. All rights reserved.
Setup Excel for VBA Programming
•
•
Open a New Excel Workbook
•
Open the VBA programming environment
- Select Tools/Macro/Visual Basic Environment (VBE)
Add the “Control Toolbox” Toolbar
- Select View/Toolbars/Control Toolbox
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 402
©1998 AspenTech. All rights reserved.
Select Reference to Aspen Plus
•
•
•
•
Make the VBE the active window
•
Select reference by clicking the check box and pressing
“OK” to complete the task and close the dialogue box
Select Tools/References
Look for “ASPEN PLUS GUI 10.0-1 Type Library”
If not found, use Browse button to find
- ...\APUI\xeq\happ.tlb
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 403
©1998 AspenTech. All rights reserved.
Place/Modify Controls (1 of 6)
•
•
Make the Excel Workbook the active window
•
Add 3 Command Buttons to the Workbook
- Select the Command Button from the Control
Toolbox toolbar
- Move the cursor on to the Workbook. It will change
to crosshairs. Click the upper left corner of cell G2
- Repeat above for cell G4, G6
Change the Workbook to Design Mode by pressing the
“Design Mode”
button on the Control Toolbox
toolbar
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 404
©1998 AspenTech. All rights reserved.
Place/Modify Controls (2 of 6)
•
Add 1 Check Box to the Workbook
- Select the Check Box from the Control Toolbox
toolbar
- Place the control on the upper left corner of cell D2
•
The Workbook should look something like this
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 405
©1998 AspenTech. All rights reserved.
Place/Modify Controls (3 of 6)
•
Select any of the controls by clicking on it to make the
small boxes appear around the edge
•
With the cursor still over the control, click your Right
Mouse button (for right-handed people). This will open
a pop-up menu.
•
Select Properties from this menu. This will display the
Properties window
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 406
©1998 AspenTech. All rights reserved.
Place/Modify Controls (4 of 6)
•
Change the properties of the controls using the info in
the table below
•
Change the control displayed in the property window by
selecting the control on the workbook or changing the
selection on the top of the property window
Control
Property
Value
CommandButton1
Name
Caption
Name
Caption
Name
Caption
Name
Caption
cmd_OpenSimulation
Open Simulation
cmd_CloseSimulation
Close Simulation
cmd_RunSimulation
Run Simulation
chk_IsVisible
Make Visible
CommandButton2
CommandButton3
CheckBox1
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 407
©1998 AspenTech. All rights reserved.
Place/Modify Controls (5 of 6)
•
When finished, the Properties window for the Check
Box should look something like this
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 408
©1998 AspenTech. All rights reserved.
Place/Modify Controls (6 of 6)
•
The Workbook should look something like this
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 409
©1998 AspenTech. All rights reserved.
Add Additional Text to Workbook (1 of 2)
•
®
Use the table to add text to the workbook
Cell
Size/Effect
Text
A1
16pt/Bold
A4
12pt/Bold
Aspen Plus/ActiveX
Demonstration
Simulation File
Septiembre 12, 2001
Introduction to Aspen Plus
Slide 410
©1998 AspenTech. All rights reserved.
Add Additional Text to Workbook (2 of 2)
•
The Workbook should look something like this
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 411
©1998 AspenTech. All rights reserved.
General Declarations
•
•
•
•
Make the VBE the active window
Select Insert/Module to create a new Basic module
Insert the following code into the module
All text in lines that start with a ‘ are comments and do
not need to be typed
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 412
©1998 AspenTech. All rights reserved.
Code Subroutine
•
•
Make the VBE the active window
•
Note: For this and all following code, the code IS
CASE-SENSITIVE
Add the following code into the Basic Module below the
General Declarations written before
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 413
©1998 AspenTech. All rights reserved.
Code Control Events (1 of 4)
• To code the specific control, make the workbook the
active window, make sure the Design Mode button is
pressed, and then Double-Click on the control
•
To code the event below, make the workbook the active
window then double click on the checkbox. The VBE
will open and the cursor will be inside the following
paragraph. The If-Then lines are what needs to be
typed
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 414
©1998 AspenTech. All rights reserved.
Code Control Events (2 of 4)
•
Code the following control event
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 415
©1998 AspenTech. All rights reserved.
Code Control Events (3 of 4)
•
Code the following control event
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 416
©1998 AspenTech. All rights reserved.
Code Control Events (4 of 4)
•
Code the following control event
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 417
©1998 AspenTech. All rights reserved.
Code Workbook_BeforeCloseEvent (1 of 2)
•
If you exit the workbook without closing the loaded
simulation, the simulation will still exist. It will still be in
memory but not accessible. To prevent this, do the
following steps
- Make the VBE the default
- Double click on “This Workbook” from the explorer
type view on the left side of the VBE. This will
create a window in the code area titled “filename ThisWorkbook (code)
- Change the drop down controls to read “Workbook”
(left selection) and “Before_Close”
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 418
©1998 AspenTech. All rights reserved.
Code Workbook_BeforeCloseEvent (2 of 2)
•
Add the following code
•
Save the file as ActiveXDemo1.xls
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 419
©1998 AspenTech. All rights reserved.
Running Demonstration
• Make the Workbook the active window
• Press the Design Mode button so it is inactive
• Press the “Open Simulation” button
- Find ActiveXDemo1.bkp on your disk
• Press the “Run Simulation” button
- The program will execute
• The Aspen Plus GUI can be made Visible/Not Visible
using the check box
•
Save the workbook, it is the starting point for the
Workshop
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 420
©1998 AspenTech. All rights reserved.
Demonstration of Input/Output
•
Objective
- Modify workbook to accept input and display output
results after running simulation
•
The modifications will do the following:
- Add additional text to workbook
- Add subroutines in the VBE
- Modify the code in the Run Command Button
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 421
©1998 AspenTech. All rights reserved.
Add Additional Text to Workbook (1 of 2)
•
Use the table to add text to the workbook
Cell
Size/Effect
Text
A7
D7
A8
D8
B9
E9
12pt/bold
12pt/bold
10pt/normal
10pt/normal
10pt/normal
10pt/normal
Input Values
Output Values
Stream 2 Total Flow Rate
Block B2 Heat Duty
lbmol/hr
MMBtu/hr
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 422
©1998 AspenTech. All rights reserved.
Add Additional Text to Workbook (2 of 2)
•
The Workbook should look something like this
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 423
©1998 AspenTech. All rights reserved.
Aspen Plus Variable Explorer (1 of 2)
•
Aspen Plus provides a way to find the syntax to specific
variables in a simulation
•
Make a copy of the Aspen Plus simulation file and use
the Variable Explorer on the copy
•
•
Found Under Tools/Variable Explorer
•
When you find the variable of interest, the syntax is
displayed in the “Path to Node” window. This text can
be copied into your program environment
All Numeric Input/Output Variables are found under
Root/Data/[Streams or Blocks]
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 424
©1998 AspenTech. All rights reserved.
Aspen Plus Variable Explorer (2 of 2)
•
The Variable Explorer will look something like this when
the proper path to the Block B2 Heat Duty is selected
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 425
©1998 AspenTech. All rights reserved.
Code Subroutines
•
Add subroutines to Module 1 in the VBE
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 426
©1998 AspenTech. All rights reserved.
Modify Run Button Code
•
Change the Run Button code to the following
•
Save the file as ActiveXDemo2.xls
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 427
©1998 AspenTech. All rights reserved.
Running Demonstration
• Make the Workbook the active window
• Press the Design Mode button so it is inactive
• Press the Open Simulation Button and load
ActiveXDemo1.xls
•
•
Change to cell A9 and enter a value between 100-101
•
The simulation will run and the results will be displayed
in cell D9
Press the Run Simulation Button
- You may have to clear dialogue boxes caused by
the Reinit command
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 428
©1998 AspenTech. All rights reserved.
Automation Workshop
•
Objective
- Add code and text to Workbook to perform the
following
• Input Temperature of Block B2 (use cell A11, keep
between 350-450 F)
• Output Total Flow Rate of Stream 9 (use cell D11)
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 429
©1998 AspenTech. All rights reserved.
Workshop Answer (1 of 2)
•
The Workbook should look something like this
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 430
©1998 AspenTech. All rights reserved.
Workshop Answer (2 of 2)
•
Modified Subroutines
•
Save the file as ActiveXWorkshop.xls
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 431
©1998 AspenTech. All rights reserved.
Additional Topics
•
•
Error Checking is not included in example
•
Covered in “ActiveX Automation of Aspen Plus” course
Further capabilities
- Changing units
- More Complex Output (RadFrac profiles, stream
reports)
- More Complex input (changing multiple
specifications, changing composition of streams)
Septiembre 12, 2001
®
Introduction to Aspen Plus
Slide 432
©1998 AspenTech. All rights reserved.
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