to be attached in the beginning of ts - 3 technical

to be attached in the beginning of ts - 3 technical
The PLANTS shall in all respects conform to International standards.
Applicable codes and standards listed in this section are intended to be
OWNER's minimum quality requirements. Platforms and walkways, stairs
and ladders shall be provided in design to ensure easy and safe access
to valves, instrument components, etc. Battery Limit PLANT is defined
as the boundaries of the PLANT where supply of raw materials, utilities
& other inputs for the PLANT would be made available and where
CONTRACTOR shall deliver products & other outputs from the PLANT
and are identified as follows All raw materials, utilities and PLANT outlet
lines (except WNA product line) shall end at its BATTERY LIMIT,
BATTERY LIMIT valve/s and companion flanges at either sides are in
the scope of the CONTRACTOR
Detailed Mechanical Design Philosophy / Specifications enclosed at here
in is intended to be OWNER's minimum quality requirements for
equipment, machinery, piping, inspection and the PLANT design. In
general, pumps and other rotating equipment, except major
compressors, shall be equipped with stand-by units as specified under
„Drive Pattern‟ in Detailed Specifications. Lube-oil coolers and filters
shall be provided with 100% standby. Only proven and modern speed
governing shall be provided for the steam-turbines. Steam condenser
design vacuum shall be minimum 0.14 Bar (abs) and temperature
maximum 52 deg C.
Adequate provisions shall be made for isolation of equipment without
causing a shutdown, so that maintenance or repair work can be carried
out on such items. (e.g. block valves on rotating equipment standby
units, block valves and bypass on control valves, etc.). All control valves
on Ammonia or any other hazardous fluid shall be provided with double
block & bleed system. All isolation valves for various sections of the
plants, process/steam vents, drains, etc. as may be required during
start-up/shut-down and during PLANT upsets shall be provided.
The design of the PLANT shall comply with the International
standards, laws, regulations, rules and codes applicable
A list of some important applicable International laws, rules,
regulations and codes (with amendments as applicable from time to
time) is given below. This list is not exhaustive.
Pressure Vessels:
ASME Sect. VIII Div. 1 & 2 latest ed.
High Pressure Vessels:
Heat Exchangers:
Shell & tube exchangers
Special Heat Exchanger
ASME Sect. VIII Div. 1 & 2 or A-D
Merkblatter or Manufacturer design
ASME sect. VIII Div. 1 & 2
TEMA-C (in case of light duty only)
Including UHX design
As per country of origin standards
Steam Generation and Superheating:
ASME Sect. VIII Div. 1 & 2.,
Boilers :
ANSI B 31.3
Steam Turbine for Fan
API 611
Storage tanks
API 650
API 620
ANSI or ASA B 31.3
Material Specification
Relevant country Standards, Act/Rules
15 A-NBC-BSS or equivalent
ASA-ASME for sizing of metering
API PR 550
Centrifugal pumps for process
PI610 8th edition
Centrifugal pumps for general services: ASME B73.1M latest
edition or relevant non API codes
Centrifugal compressor:
API 617
API 614 (Lube oil - Seal oil system)
Reciprocating compressor: API 618
Reciprocating pumps:
Manufacturer's Standards
Steam turbines &
Tail Gas Expander API 611 (for general purpose)
API 612 (for special purpose)
High Speed Gear:
Fire fighting System:
NEPA Standards Fire protection
system shall be in line with LPA to
meet GNFC standard insurance
Buildings, Plumbing, Sanitation:
Relevant country Standards
Noise Level
Relevant country Standards
API 661
API 662
API 941
NACE etc.
ANSI/ ASME B 73.1 M Horizontal,
End Suction centrifugal Pumps for
Chemical Process
International Standard Horizontal Centrifugal Pumps for Clear
Cold Water
API 616 Gas Turbines for Petroleum, Chemical and Gas Industry
API 619 Rotary Type Positive Displacement Compressors for
General Refinery Service
API 670 Vibration, Axial-Position, and
Bearing- Temperature Monitoring
API 671 Special Purpose Coupling for
Refinery Services, Petrochemical and
Gas Industry
API 672 Packaged, Integrally Geared
Centrifugal Compressor
for General Refinery Service.
API 673 Special Purpose Centrifugal
Fans for General Refinery Service
API 674 Positive Displacement PumpsReciprocating
API 675 Positive Displacement PumpsControlled Volume
API 676 Positive Displacement PumpsRotary
API 682 Shaft sealing Systems for
Centrifugal and Rotary Pumps
AGMA 420 Practice for Enclosed
Reducers or Increasers using Spur,
Helical, Herringbone and Spiral Bevel
AGMA 421 Practice for High Speed
Helical Gear Units
NEWA SM 23 Steam Turbine for
Mechanical Drive Turbine
Other applicable code and standards shall be mutually agreed
upon between CONTRACTOR & OWNER. All codes & standards
should be of latest edition, unless otherwise, specifically
mentioned herein.
Process Design Philosophy
Columns and Vessels:
Given below are the minimum equipment design condition requirements.
Design Pressure
Factors like pump shut-off conditions, pressure drops in recycle loop
etc. shall be considered for fixing design pressure. Pump shut-off shall
be calculated at 1.25 x rated differential pressure + max. Suction
Equipment which could have to bear the shut-off pressure of a pump
in case of a valve closing (either control valve or block valve) is
designed for the following pressure:
Design pressure = Design pressure of the suction vessel + liquid
height at vessel HLL at pump suction + 125% of pump differential
The above calculated design pressure must be checked with the shutoff pressure based on vendor data and higher of the two shall be
When operating pressure is less than or equal to 100 kg/cm2g, design
pressure shall be equal to normal operating pressure plus 10% (min.
2.0 kg/cm2). When operating pressure is more than 100 kg/cm2g,
design pressure shall be equal to normal operating pressure plus 5%
(min 10 kg/cm2).
All steam handling / condensate vessels shall be designed for full
vacuum conditions also.
All vessels / columns subject to internal pressure shall be designed to
withstand a minimum external pressure of 0.175 kg/cm2 abs.
Minimum design pressure for all equipment shall be 3.5 kg/cm2g.
Full vacuum will be specified for isolable equipment containing fluid
having a vapor pressure lower than atmospheric pressure at ambient
For equipment subject to pressure and temperature swings, the
magnitude and frequency of these swings will be given on the
specification sheet.
When several pieces of equipment are protected by the same relief
valve, each piece of equipment will be designed at least for the
pressure imposed by the discharge conditions of the relief valve in
case of emergency.
For columns, the reference design pressure shall be taken as that at
the bottom of the column.
The equipment normally working under vacuum or subjected to steam
out during start-up etc. shall be designed for full vacuum. Additionally,
such equipment shall be designed with the highest pressure it can
experience on account of vacuum failure, or maximum operating
pressure or steam pressure, which ever is higher as operating
pressure plus the standard over design.
Design temperature
For the unfired pressure vessels and their interconnecting piping,
which operate at temperatures between zero and 400°C, the design
temperature will be equal to maximum anticipated operating
temperature plus 30°C. The same will be considered at 28°C, if the
vessel operates above 400°C.
Conditions like steam-out (for handing out vessel to maintenance) will
be considered while specifying design temperature.
For vessels operating at ambient temperature, 65° C will be used for
mechanical design.
For operating temperatures below 0° C, design temperature shall be
minimum operating temperature - 5° C or minimum ambient
temperature, whichever is lower.
Liquid Residence Time
Following criterion of minimum residence time (as defined between low liquid
level and high liquid level) shall be followed for vessels sizing.
Residence Time
5 minutes
Column feed
15 minutes on flow control
Or 8 minutes on cascade level / flow control
Reboiling by heater
10 minutes on feed to heater
Reboiling by thermo siphon
10 to 30 seconds
Product to storage
2 minutes
Product feeding another unit
15 minutes on flow control
Or 8 minutes on cascade level / flow control
Feed surge drum
30 minutes
In the case of pumps ensuring several services such as reflux and liquid
distillate to storage, the residence time of the corresponding vessel will be
whichever is greater from the above list.
Other Specifications
Vessels will be sized according to inside diameter and 2:1 elliptical
heads or hemispherical heads. Minimum inside diameter shall be 500
mm. Top cover shall be flanged if the ID is equal or less than 900 mm.
All connections shall be flanged. Minimum nozzle size in vessels shall
be 2".
24" manhole shall be used for all vessels with internal diameter more
than 900 mm. Columns of internal diameter below 900 mm shall be
flanged at one head for access with a 12 " hand hole on the other end.
Other vessels of internal diameter below 900 mm shall also be flanged
at one head, however, a 6" hand hole shall be provided on the other
Larger size manhole will be specified when required to accommodate
internals or critical for vessel entry.
In tray columns, manholes will be provided above the top tray, at the
feed tray, at any re-distribution level and below the bottom tray. A
manhole will be provided at any tray with removable internals.
Minimum numbers of manholes in the tray columns shall be 3. One
manhole for every 6000 mm or 10 trays, whichever is less, will be
provided in all tray columns.
A manhole shall be provided on the column bottom partition wall, if
For packed columns, manholes shall be provided above and below
each packed bed.
All vessels will be provided with vent and drain nozzles. Other than for
process reasons, the vent and drain sizes will be specified as defined
in 'Special Design Requirements'.
Where ever intended, separate permanent steam-out connections will
be specified for the vessels.
In vertical vessels with demister, manholes shall be provided on to
access both sides of the demister.
In horizontal vessels, the manhole shall be located on one of the
heads, which is away from internals such as displacers, baffles etc.
The vent connection on the horizontal vessels shall be on the opposite
end of the manhole. Large vessels with diameter of more than 3000
mm TI- TI, an additional 4" vent nozzle with blind shall be provided.
For small diameter towers (diameter < 900 mm), tower internals shall
be cartridge type, which can be removed from one end. Necessary end
flanges shall be provided. where necessary, along the tower.
Trays & Packing
All columns shall be sized to correspond to 110% of normal flow rates.
Valve trays in stainless steel construction will be used.
Valve tray columns will be specified with a maximum flooding factor of
70 for all applications.
Operating range for the trays will be at least 50 to 110% of normal
Trays will be numbered from the bottom.
Random packing shall be considered, only where it is absolutely
For random packing, a 12" hand hole shall be provided at bottom of
Heat Exchangers / Condensers / Reboilers:
General Guidelines
Plate type heat exchanger shall not be used generally except critical
services like Combustion Air Pre-heater and cryogenic conditions.
Straight tube length for all shell & tube heat exchangers shall be
optimized for the duty.
Following criterion for tube diameter & thickness shall be followed as a
The tube diameter and thickness for Carbon Steel and low alloy (up to
and including 5 Cr, ½ Mo) tubes shall be 20 x 2 mm (minimum) and 25
x 2.5 mm (minimum) respectively.
The tube diameter and thickness for high alloy (above 5 Cr ½ Mo and
Austenitic) tube shall be 20 mm & 25 mm x t to suit design.
No copper or its alloys shall be used as tube material.
The tube pitch shall be square pitch in fouling services (Shell side
fouling > 0.0004 h C m2 / kcal)
For all water-cooled heat exchangers, back-flushing facilities shall be
provided with a minimum size of 4". Return Water line from each cooler
shall be provided a globe valve and a water sample connection.
All wetted parts of Lube Oil exchangers shall be of SS. Cooling Water
exchangers shall have SS tubes wherever CW is in tube side.
Shell and Tube heat exchangers
Thermal design of shell & tube heat exchangers shall be done
according to TEMA 'R' / “C” specifications. The pressure parts and
tube sheets shall be designed as per ASME Section VIII Div. 1 UHX
latest edition.
For utility fluids, following fouling factors shall be considered –
Cooling Water - 0.0004 h.m2.oC/Kcal
- 0.0002 h.m2.oC/Kcal
- 0.0002 h.m2.oC/Kcal
Following minimum fouling factors, if not specified otherwise, shall be
used based on heat exchanger type :
Shell side fouling
Tube side fouling
> 0.0002
> 0.0002
< 0.0002
> 0.0002
Fixed T / sheet
> 0.0002
< 0.0002
U-tube bundle
< 0.0002
< 0.0002
Fixed T/sheet or
U-tube bundles
For stacked heat exchangers, maximum two shells shall be stacked.
Only if the shell diameter is less than 500 mm, a stack of three shells
will be permitted.
A minimum cooling water velocity of 1.0 m/s shall be maintained while
designing the water cooled heat exchangers. The cooling water
pressure drop across heat exchanger shall not exceed 0.5 kg/cm2.
Corrosion allowance
Unless otherwise specified, corrosion allowance for all exchangers
should be as per TEMA standard (Class R / Class C).
For U tube exchanger, minimum radius of U bend shall be at least 3
1.5 times of the tubes OD.
Design pressure for heat exchange equipment
When operating pressure is less than or equal to 100 kg/cm2g, design
pressure shall be equal to normal operating pressure plus 10% (min.
2.0 kg/cm2). When operating pressure is more than 100 kg/cm2g,
design pressure shall be equal to normal operating pressure plus 5%
(min 10 kg/cm2).
Exchangers that are subject to pump shut off, in general, shall have
design pressure equal to maximum shut off pressure as follows.
Equipment which could have to bear the shut-off pressure of a pump in
case of a valve closing (either control valve or block valve) is designed
for the following pressure:
Design pressure = Design pressure of the suction vessel + liquid
height at vessel HLL at pump suction + 125% of pump differential
The above calculated design pressure must be checked with the shutoff pressure based on vendor data and higher of the two shall be
In case exchanger is operating under vacuum or in steam service, the
design shall be for full vacuum.
In addition to above criteria, design pressure of an exchanger shall
also reflect the location and set pressure of the safety relieving valve
protecting it.
For high differential pressure, the design pressure of lower pressure
side shall be at least 0.77 x higher pressure side design pressure.
Design temperature for heat exchange equipment
Exchangers operating between zero to 400°C shall be designed for the
maximum anticipated operating temperature plus 28° C but not less
than 75°C.
In case of possible loss of flow of cooling media, the tubes may be
subjected to full process inlet temperature with no margin. These
components shall be designed for maximum process anticipated
temperature of hotter medium.
Exchangers operating at 0°C and below shall be designed for minimum
anticipated temperature. For operating temperatures below 0°C,
design temperature shall be minimum operating temperature - 5° C or
minimum ambient temperature, whichever is lower.
The effect of auto-refrigeration due to depressurization to atmospheric
pressure will be taken into consideration (LPG systems for example).
Spare philosophy:
100% spare for continuous service and critical intermittent service,
unless other wise specified specifically.
Drive of pumps:
Electric Motor, unless otherwise specified for process/safety reasons.
Centrifugal pumps shall be as per API 610 8TH edition.
For NPSHa calculations, minimum liquid level, minimum upstream
vessel operating pressure, maximum operating temperature for vapor
pressure and maximum rated capacity for friction losses shall be
A margin of at least 1.0 m between NPSH available and required
NPSH shall be applied. In case of requirement of lower difference,
concurrence of Owner / PMC shall be obtained.
Equipment which could have to bear the shut-off pressure of a pump in
case of a valve closing (either control valve or block valve) shall be
designed for the following pressure:
Design pressure = Design pressure of the suction vessel + liquid
height at vessel HLL at pump suction + 125% of pump differential
The above calculated design pressure must be checked with the shutoff pressure based on vendor data and higher of the two shall be
A minimum flow bypass (back to the upstream vessel / drum /
separator) with flow control valve for centrifugal pumps shall be
specified for the following cases:
high differential pressure multistage pumps (water differential head >
large pumps with driver power > 180 kW
for process reason (turndown), flow rate < 30% of max flow rate
The control valve at the pump discharge with 'fails in close'
specification or controlled by upstream vessel level.
Minimum flow of pump being more than the process minimum flow.
Normal driver shall be electrical motor. Critical service drivers will be
connected to electrical emergency network.
Common spares can be specified whenever appropriate for metering
All pumps shall be provided with bridle cooling water lines (for bearing
cooling, gland cooling, seal cooling), as per vendor information. The
cooling water return from pumps shall be collected in an underground
concrete sump and the same shall be pumped to the main return
The size of cooling water lines to / from each pump shall be minimum
1" NB. Pump vendor's battery limit for cooling water shall be 1" NB
ASME B16.5 flange with counter flanges, gaskets, fasteners for both
CWS and CWR lines at individual pumps.
Sight glass for cooling water flow at pump (bearing housing, seals etc.)
shall be ball type.
Drains from pump base plates shall be routed, through an open funnel
and pipeline, for each individual pump, to nearest oily water sewer
catch point.
Temporary strainers shall be provided on all pumps for start-up.
Basket type strainers shall be provided for Hydrocarbon / MDEA
solution Pumps.
Pumps provided for waste water like, BBD, CW blow down, open /
close drain pit, shall be designed with sufficient head so that discharge
reaches relevant treatment unit.
Process Control and Instrumentation:
Control Room
The state-of-the-art, control room arrangements shall be built by the
CONTRACTOR in existing NPP control room to accommodate new
installations for this new Weak Nitric Acid PLANT.
All process and product streams shall be measured and recorded.
Level alarms, wherever required, shall be used.
For Thermocouples in Temperature Control Loop, closed loop,
temperature compensation / correction loop or connected to PLC,
Temperature Transmitters shall be used. For other open loop
Temperature indications, 'K' type thermocouples with connection to
DCS shall be used.
Control Philosophy
The plant shall be operated through DCS Consoles along with Console panel
with dedicated Instruments, Recorders, Annuniciators etc. and a Console
desk having selector switches, push buttons & status indicators.
The Interlocks (LOGIC) for the unit shall be performed in PLC capable of
communicating with DCS. 2-out-of-3 voting logic is envisaged for all critical
All alarm points, Software and hardwired shall be indicated in P&ID
with proper legend as per ISA symbol.
All specification data sheets shall be as per ISA.
For security interlocks, transmitters shall be used as field instruments
connected to Analog Input card of PLC directly. No switches shall be
For all field instrument of pressure, Temp, flow, level etc. only
transmitters shall be used and switches shall not be used.
For all temperature closed loops & interlock loops, temperature
compensation/correction loops, field mounted temperature transmitters
shall be used and head mounted shall not be used.
1 ½” flanged type thermowell with minimum flange rating of 300# shall
be considered. Screwed type thermowell will not be used.
Dedicated field instruments (Transmitters) shall be used for trip
activation and critical alarms. Separate nozzle / tapping shall be used
for such instruments.
Limit switch : proximity type limit switch shall be used.
The symbols to be used will be in accordance with ISA.
Alarms and shutdown devices:
Alarms and shutdown devices will be specified where required for
process, safety or equipment protection considerations.
Shutdown device connections except flow shall have independent
primary elements and independent connection.
All safety related interlocks shall be connected to a PLC
(Programmable Logic Controller). Non-critical logics shall be through
2 out of 3 voting logic with field instruments shall be provided for all
critical parameters.
For shut down valves, the valve position shall be made available in
DCS through proximity switches.
Instrument impulse lines shall be insulated / traced, wherever required,
to avoid condensation /congealing.
Critical rotating equipment to have vibration monitoring system with
control room indication.
All vents from all instruments in lighter hydrocarbon shall be connected
to suitable flare network.
All drains from all instruments in hydrocarbon service shall be
connected to closed slop system.
PG and PT tapping shall be withdrawn separately.
Safety Valves
All hydrocarbon / combustible gases and vapors shall be relieved to a
closed flare system.
Nitrogen shall be provided in all dead ends of flare header for
continuous purging. The permanent nitrogen connections shall be
provided with double block valves (one isolation valve and one
controlling), spectacle blind, rotameter and a bleeder (with valve and
Double safety valves shall be provided with isolation valves, such that
on-stream isolation and maintenance of a safety valve is possible
without affecting unit operational safety requirements. This shall be
considered for all operation failure cases (guided or no-guided).
All isolation valves of pressure safety valves shall be lock open/close
All pressure safety valves shall be provided with a bypass line with
double block valve and a spectacle blind in between. No bypass is
required, when depressurization of the upstream equipment to flare is
possible through accessible valves & suitable piping.
Pressure relief valves are normally installed on the equipment.
All relief valves load and size shall be calculated according to the
following mentioned codes:
API RP 520
API RP 521
API 526
API 527
API 2000
Following typical over pressure conditions shall be considered :
Blocked Discharge
Cooling Water Failure
Loss of Air Cooler Fans.
Loss of Instrument Air or Electric Power
Reflux Failure
Heat Exchanger Tube Failure
Trapped Liquid Expansion
External Fire
Where ever vacuum conditions in the system are likely to occur, the
system shall be designed for full vacuum.
The following guidelines shall be applied for safety valve selection and
line sizing:
Valve selection will be based on maximum operating temperature and
relief valve set pressure.
Conventional type relief valves shall be used for the cases where the
built-up back pressure and the variable superimposed backpressure
doesn't exceed 10% of the set pressure. For the cases, where it
exceeds 10%, but is below 30 % of the set pressure, balanced bellow
type relief valves shall be used. For the cases, where the total back
pressure is between 30 & 50% of the set pressure, the balanced
bellow type relief valves may be used subject to confirmation from the
manufacturer that there is no decrease in the capacity of the pressure
safety valve due to high back pressure.
Relieving device discharge lines shall be sized based on the back
pressure data. The sizing shall be done so as to limit the maximum
back pressure at the discharge of a PSV up to 30% of its set pressure.
However, if it exceeds 30% but is below 50% of the set pressure,
necessary confirmation, as defined above, from manufacturer must be
The discharge velocities shall not exceed 0.5 mach no.
PSV discharge shall be free draining to flare header. PSV inlet shall be
free draining towards the source. The inlet lines to safety devices shall
be sloped back to the protected equipment and the discharge lines
from safety devices shall be sloped towards the respective knock out
drum. These lines shall be without pockets.
Pilot operated relief valves shall be used for the systems where
maximum set point accuracy is required. Such relief valves shall be
installed in equipment, which operate very close to the set pressure.
Safety valves on column circuits shall preferably be located at the
highest point in the overhead vapors lines. In case, these are located
at a lower elevation on the overhead vapor line, the inlet line of the
safety valves must be self draining to prevent any liquid accumulation
and the pressure drop in the inlet circuit of the safety valve must meet
the API guidelines for maximum allowable pressure drop.
Pressure drop in a PSV inlet line must not exceed 3% of the set
pressure of the PSV.
PSV inlet and outlet line sizes shall be equal or greater than the PSV
nozzle sizes.
Inlet and outlet isolation valves of PSVs shall be full port.
All relief valves, which are susceptible to plugging, shall be steam
traced and have a rupture disc installed under them.
Staggered pressure setting may be specified to minimize losses.
For atmospheric relief, the open end of discharge will be located 30m
from any source of ignition. Discharge shall be 3m higher than any
equipment or manholes (ladder, platform etc.) within 15m radius, or 2
meters above the top most technological platform, which ever is
The relief valves on storage tanks shall be as per API codes to take
care of over filling also.
Thermal Safety Valves (TSV) shall be provided for the protection of
equipment and lines, where ever there is possibility of blocked liquid
getting heated up on account of another heating medium or direct sun
light. The discharge of TSVs shall be appropriately routed to local drain
for cooling water and slop system for hydrocarbons.
The flare header shall be sized according to pressure drop constraints.
The discharge line of all liquid safety valves discharging to atmosphere
shall be routed to appropriate drain system.
All drains on safety valves (wherever provided) shall be connected to
the slop system. The discharge piping of safety valves shall be
provided with safely routed small drain line at lowest location to
remove any condensed/carried liquid.
All safety valves shall normally have carbon steel body with stainless
steel trim. Bronze or cast iron bodied valves shall not be used.
Control Valves
As a default, control valves up to 8" size and in steam service shall be
provided with a manifold of block and bypass valves. Bypass valves
shall be globe valves. For control valves above 8”size, block and
bypass requirement shall be decided on case to case basis. However,
Control valves not having block and bypass provision shall be provided
with hand wheel for manual operation.
Control valves shall be designed considering instrument air pressure at
4.0 bar g.
All control valves shall be provided with a minimum ¾ " drain
connection with valves, which shall be provided as:
Upstream and downstream of all control valves
Drain valve shall be capped (In non-hydrocarbon & non-IBR LP steam
Drain valve shall be blind flange (In all Hydrocarbon, toxic / hazardous
chemicals & IBR steam service).
Shut down valves connected with ESD system shall not be provided
with block and bypass valves.
The control valve pressure drop should be the greater of the following
50 -60 % of the total frictional loss excluding the control
0.7 Kg/cm2
15 % of the pump differential head
For control valves installed in extremely long or high pressure drop lines, the
percentage drop across control valve may be lower, but at least 15 % up to
25%, where possible, of the system friction drop.
The selected control valve must allow maximum operating flow through
it at 80% opening (maximum) and minimum operating flow at 15 to
20% opening minimum.
Control valves must be evaluated for flashing / cavitation and choked
flow condition before selection.
All critical control valves shall have smart positioners with position
transmitter. For non-critical control valves, conventional E/P positioners
shall be provided.
Flow Indication:
Flow indications with totalizer for the following streams entering /
leaving the battery limit shall be available in the control room over and
above those required for process control of the unit:
All hydrocarbon /N2 inputs to the units
All hydrocarbon/Syn Gas/CO2 /Steam outputs & off gases from the
The steam flow indication at battery limit shall be pressure and
temperature compensated for accuracy.
Battery limit flow measurement for NG / R – LNG and Product
Ammonia Syn Gas shall be high accuracy type for guarantee
Level Instruments:
Standpipes with a default size of 2" NB shall be considered for only
clean, non-viscous and non-crystallizing services. Standpipes shall be
used if more than 4 vessels nozzles are anticipated for mounting all the
level instruments in a given service.
When directly mounted, LG and LT tappings shall be provided on
different nozzles.
Level nozzle size shall be minimum 2".
Standpipes bottom tapping shall be from side only. Standpipe bottom
tapping shall not have any low pocket in order to ensure free draining
of standpipe liquid into the vessel.
All standpipes shall have drain and vent connections. The isolation
valves shall be provided for isolation of stand pipe from the vessel and
isolation of each instrument connected to the standpipe.
Following specific requirements for standpipes are to be followed:
Standpipe shall not have instruments other than for level.
Standpipe accommodating level gage / transmitter shall be separate
from standpipe / vessel nozzles for level switches for alarm and trip.
Standpipe shall not be connected to process lines.
All standpipes shall have isolation valves at top and bottom tapping.
Standpipe bottom tapping shall have slope towards the vessel.
Standpipe connections shall be on sides only.
DP type level measurement shall be used in Test Tanks and radar type
level measurement shall be specified for critical product Tanks.
All remote seal type level transmitters shall have 3" nozzle size only.
Standard Heat Exchanger Instrumentation
The following shall be followed as a minimum for all heat exchangers –
Isolation valves shall be provided at both inlet & outlet lines in cooling
water service.
Isolation and bypass line with valves shall be provided for exchangers,
which need to be taken out for maintenance when plant is running
DCS TI at cooling water outlet of each exchanger.
DCS TI at process inlet and outlet of each service
DCS PI at process inlet & outlet of each service
Local PI at cooling water outlet of each exchanger
TSV at cooling water return line of each exchanger with isolation
Sample connection on cooling water return line of each exchanger
Vent connection with valve & blind at cooling water outlet.
On line back flushing arrangement for exchangers using cooling water
(size of at least inlet cooling water piping).
Safety Recommendations:
Shutdown of pumps by low level in upstream vessel
Automatic shutdown of the pumps by low level in upstream vessel shall
be specified for all pumps in continuous service. For pumps in
intermittent service. The automatic shut down of the pumps on low
level in upstream vessel shall be decided on case to case basis during
detail engineering.
Automatic isolation valves between process vessel and pumps
Automatic remote operated isolation valves shall be provided at the
outlet pipe of all critical products and Test Tanks.
High level in feed drum
To avoid overfilling, an independent high level alarm (LAH) shall be
specified. The feed surge drum high level alarm will be provided with
an interlock to close the upstream on-off valve.
Seals on pumps
Dual mechanical seals (pressurized or un-pressurized according to
process considerations) shall be considered for all Hydrocarbons.
Single mechanical seal shall be considered for water service.
Additional safety requirements
Additional push buttons housed in protected case or similar
arrangement for stopping critical motors shall be provided at a safe
location with protection from spurious operation, at least 15 m away
from the fire-zone of respective motors and in control room. This is in
addition to normal start-stop push buttons provided for such motors.
Additional stop push button for air coolers shall be located at grade
level in addition to start-stop button near the fan at platform.
Suction / discharge valves and suction strainer shall be close to the
pump in order to avoid fluid wastage during strainer cleaning and pump
All valves located on flare lines shall be installed in horizontal line.
Flare line isolation valve at unit battery limits shall be installed only in
the horizontal line with stem in vertical downward position to avoid free
fall of gate and blockage of flare system. Each flare header leaving a
unit shall be provided with such isolation valves to facilitate
maintenance of flare piping and pressure relief valves within the unit.
Critical Pumps shall have a DCS stop facility in central control room
along with running lamp indication.
Emergency trips if specified for HT motor shall be wired directly to
switch gear in addition to control room.
Double isolation valves with spectacle blind & bleed shall be provided
at each battery limit in all the process & utility lines.
All the valves and Instruments shall be provided at approachable
height with suitable platforms ensuring accessibility, safety and ease of
Flame arrestors shall be provided on Hydrocarbon Tanks and Product
Test Tanks.
Utility Stations, Safety Showers & Eye wash
Drinking water shall be used for eyewash and safety showers. The
locations shall be located strategically during detail engineering. The
drinking water lines shall be laid above ground and without insulation.
Each utility station shall be provided with LP steam, plant air and
service water outlets. Nitrogen connection shall also be provided at all
utility stations, but will be located little away from the other outlets.
A dedicated LP steam header shall be considered for supplying LP
steam to Utility stations if required.
All utility outlets at utility stations shall terminate with a hose
connection of minimum size 1”.
Assuming a maximum hose length of 25m, utility stations for LP steam,
plant air and service water shall be provided at the following locations :
At grade to serve all equipment within maximum 25m radius
At all platforms of structures
At those platforms of self-standing towers
- Where man-holes/hand holes are located.
- Top and bottom platform
- Every alternate platform
However, only a single riser for LP Steam, Service Water and Plant Air shall
be installed with single utility station at above mentioned locations. The riser
will have facility to connect through hose to anyone of the above services at
the bottom of the self standing tower. For nitrogen, it will be a separate
permanent connection at all the above mentioned locations.
At top platforms of drums located at the grade
Near the pumping stations and tanks
Technological Platform -two (minimum) per platform level including
grade, beyond 15 m length/width, provide additional utility point.
A permanent Nitrogen connection will be provided to the utility
connection of all the columns.
Material Selection Philosophy
Suitable material to be selected for equipments, items, machinery etc.,
for various sections of the PLANT, which under normal operating
conditions will not be subject to material related failures.
Materials shall be specified according to the relevant design code
ASTM/ASME/API or equivalent.
No parts bearing Copper/Cu alloys shall be used for the PLANT.
In the material selection the operation conditions including start up and
shutdown, site conditions etc are to be considered.
Following items may influence the material selection
Mechanical, thermal and cyclic conditions
Safety, plant availability
Material Delivery Situation.
If more than one material are suitable, the most economical choice will
be taken.
The selected material shall not be susceptible to undue localized
corrosion or stress corrosion cracking under normal operating
conditions of the PLANT.
General Corrosion will be taken into consideration by provision of
sufficient Corrosion Allowance (CA).
Materials for high temperature applications are normally calculated
with their 100,000 h creep rupture strength values.
Materials for low temperature service have to show adequate ductility
at the lowest design temperature.
In the case of cyclic loads on pressure bearing equipment, fatigue
calculations will be performed to prevent pre-mature failures.
In the case of carbon steel heat exchanger tubes the life time of heat
exchanger is to be optimized between corrosion aspects and heat
transfer requirements.
If not specified separately carbon and low alloy steels are suitable with
yield strength < 370 N/mm2 (53 ksi) and tensile strength < 500 N/mm2
(72 ksi), minimum values each according to the material standard
used. The carbon content according to the ladle analysis shall be <
0.23% for piping material supplied by the Contractor.
If not specified separately unsterilized austenitic CrNi-steels like Tp
304 or Tp 316 may be used for welded components up to a wall
thickness of 6mm, above 6mm low carbon grades like Tp 304L , Tp
316L or stabilized materials like Tp 321 shall be used. In systems in
low temperature service, unsterilized austenitic CrNi-Steels may be
used for all thickness.
Austenitic stainless steels shall be free from annealing colors, ferritic
inclusions etc.
The alternative use of CS with SS cladding shall be considered for all
high pressure SS vessels.
Design of PLANT components those will be in contact with CW with
consideration that CW is operated in a cycle (circulated) and is treated
in a manner that the corrosion rates for CS are < 0.1 mm per year. The
CW treatment shall be specified by the Contractor accordingly.
Owner prefers to have cooling water on tube side of the heat
Tube bundle of Heat Exchangers and inter-coolers / after-coolers,
Lube oil coolers etc. with cooling water services must be of stainless
steel to prevent future corrosion and fouling problems. These
specifications are applicable to package units also.
All ladders and platforms in the pit shall be of SS 304.
IBR Requirement
Steam generators/steam users shall meet IBR regulations. Major IBR
requirements are summarized below:
Vessels: Any closed vessel exceeding 22.75 liters {five gallons) in
capacity which is used exclusively for generating steam under
pressure and include any mounting or other fittings attached to such
vessels, which is wholly or partly under pressure when steam is shutoff.
Piping: Any pipe through which steam passes and if:
- Steam system mechanical design pressure exceeds 3.5 kg/cm2 {g) or
- Pipe size exceeds 254 mm internal diameter
The following are not in IBR scope
- Steam Tracing
- Heating coils
- Heating tubes in tanks
- Steam jackets
All steam users {heat exchangers, vessels, condensate pots etc.)
where condensate is flashed to atmospheric pressure i.e. downstream
is not connected to IBR system are not under IBR and IBR
specification break is down at last isolation valve upstream of
All steam users where downstream piping is connected to IBR i.e.
condensate is flashed to generate IBR steam are covered under IBR.
IBR starts from BFW pump discharge.
Safety valves / Relief valves on IBR system shall have isolation valves
as per general philosophy.
All Nitric acid line valves shall be of plug type IGC tested with third
party inspection.
TSP, Hydrazine, Hydrogen service piping and components shall be of
SS. TSP, Hydrazine tanks shall have motorized agitator.
Material Certificate
All items which are part of steam piping i.e. pipes, valves, fittings,
traps, safety valves must have material certificates, countersigned by
the local boiler inspectors.
For imported items -Certificates issued by an authority empowered by
Central Boilers Board {As per IBR) or under the law in force in a
foreign country in respect of boilers manufactured in that country may
be accepted. In case of imported boiler IBR items, prior advice,
Drawing approval for fabrication from Director of Boiler, Gujarat State
and Boiler Board, New Delhi, India shall be obtained.
All drawings coming under purview of IBR shall be certified by Local Boiler
Special Design Requirements
In case of remote operated valves, (critical service} indication of valves
position shall be available in the control room.
Shut down valves shall be operable from control room.
Instrument and electrical cables shall be above ground.
The following non-standard line sizes shall not be used unless
approved by OWNER / PMC
¼” , 2 ½", 3 ½", 5", 7", 9"
The following guidelines for minimum line / nozzle sizes shall be
applied –
2" NB
Minimum nozzle size for vessels, tanks and heat
2" NB
Minimum process (hydrocarbon) line size
1 ½ ”NB Minimum utility line size
¾ ”NB
Minimum bridle drain or pump casing vent / drain
½ " NB Minimum chemical injection line size. Tubing size
to be 10 mm
1 ½ " NB Minimum on pipe rack
4" NB
Minimum for underground lines
The following roughness coefficients shall be used unless stated
otherwise –
Roughness (inches)
Carbon Steel
Flare / Vent headers (Heavily corroded)
Stainless Steel Pipe
Glass Reinforced Epoxy Pipe
Vents & Drains in Heat Exchangers
If high point vent and low point drain are not available, 2" NB x 300#
(min.) flanged vents and drains shall be provided at high and low
points respectively on all heat exchangers. All vents and drains shall
be having valves and blinds.
Exchangers in total condensing service shall be provided 2" vent
connection at the opposite end of the shell inlet.
All heat exchangers shall be provided with a multi-purpose connection
on all the nozzles. Sizes of multi-purpose connections and pressure
gauge connections on exchanger nozzles shall be 1” NB x 300# (min.)
for below 12" nozzles and 2" NB x 300# (min.) for 12" & above nozzles.
Vents & Drains in Piping
Pipe Size in Inches
Vent Size, inches Drain Size, Inches
4 & below
6 to 10
12 & above
Vents & Drains in Pump Casing
For non-volatile services, casing vents and pump drains shall be
routed to appropriate sewer or closed drain system.
For volatile services, casing vents and drains shall be routed to the
relief header and sewers.
Double Block Valves Philosophy
Double block valves with blind and bleed shall be provided for the
following conditions
All incoming & outgoing lines to/from the unit with bleed and spectacle
For cases where cross contamination can't be tolerated.
For vents and drains in ANSI Class 600 rating and above
For drains containing C5 or lighter hydrocarbons. In this case, the
double block valves must be minimum of 1000 mm straight pipe apart.
Where high pressure (above ANSI 300# rating) is likely to be removed
on the run; e.g. spare machinery or equipment
For gas stream > 100 bar g or liquid systems > 60 bar g or gas/liquids
which are potentially toxic.
For the equipment, which may be opened for maintenance on the run
e.g. filters
Block valves of 12" diameter & above shall be gear operated.
Injection Points and Sample Connections
Sample connections shall consist of a NPS ¾ " shut-t T valve. For
applications, where throttling is required, a secondary throttling (globe)
valve shall be installed. Sample connections shall be installed in the
side of the pipe rather than the top or bottom. Provisions shall be made
to collect excess fluid from the sample point in a drain or sump.
Sample coolers shall be provided for all sampling connections from
piping or equipment when the service temperature is 77°C (170°F) or
higher. Sample lines shall be as short as feasible and braced to protect
them from mechanical damage. The sample lines shall be brought to
ground level to avoid hazardous situation.
Injection points where a fluid (such as additive, corrosion inhibitor, etc.)
is to be injected into a line shall be designed so the fluid is injected into
the centre of the pipe. The location of the injection point shall be from
the top of line and shall not be immediately upstream of an elbow.
Check valves shall be provided at all chemical injection points to
Process systems to prevent process fluid from entering in to the
chemical system.
CONTRACTOR shall provide Hazardous area classification.
HAZOP study is included in the scope of the CONTRACT.
HAZOP study shall be jointly conducted by OWNER,
CONTRACTOR / Technology supply from abroad and all
changes, additions, etc. Agreed during HAZOP study shall be
incorporated by the CONTRACTOR without extra cost.
While considering the execution and operating of the Project, the Safety,
Health and Environment (SHE) Management policy becomes key issue and
elaborate the arrangement CONTRACTOR has to make. OWNER also has
policy related to Plant Safety, Health and Environment which complies with
the referenced legislation, regulations, standards, policies and procedures
prescribed by the Government or any regulatory authorities.
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