ammonia slide blok diagram cv nghjyujkm bnmc ndfhg nvbnbmgh
TRANSCRIPT
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Ammonia
Basic Flowsheet Elements
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Chemistry of the Ammonia Process
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Simplified Block Diagram of a Typical
1000 t/d Ammonia Plant
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Simplified Block Diagram of a 2000
MTPD Methanol Flowsheet
Methanol
Purification
Reforming
Compression Distillation
Synthesis
Steam Raising
Feedstock
(CH )4
Water
VHT-S103
20 m
VSG-EZ200
VSG-Z101
40 m
VSG-Z101
40 m
VSG-A101
200 m
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Simplified Block Diagram of a
Hydrogen Flowsheet
Desulfurization
Primary Reforming
High Temperature
CO Shift
VHT-S101
VSG-
Cl101
VSG-
EZ200
VSG-
Z101
VSG-
F101
PSA
etc
SteamNatural Gas Feed
Hydrogen
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Simplified Flowsheet for a Typical
Ammonia Plant
NaturalGas
Steam
superheater
Air
Steam
30bar
Steam
Steam
raising
350 C200 C
HeatRecovery
Steam
raising
Cooling
Cooling
Reboiler
CO
Cooling
Preheater
Heat
Recovery
Steam
Boiler
ProcessCondensate
Quench
Quench
Liquid Ammonia
H
Hydrodesulphuriser PrimaryReformer
SecondaryReformer
HighTemperature
Shift
LowTemperature
Shift
Ammonia Syn thes isMethanator
Carbon Dioxide
Purge Gas
Cooling
400 Co
390 Co
2
790 Co
550 Co
1000 Co
o
420 Co
150 Co
400 Co
470 Co
o
220 Co
290 Co
330 Co
2
CO Removal2
220 bar
Refrigeration
CondensateCooling
Ammonia
Catchpot
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Modern Conventional Flowsheets
Main process steps are the same for all plants
Main differences in equipment design
Uhde
Top fired reformer
Proprietary exit header design
Secondary reformer has a riser
HP loop with radial flow converter
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Modern Conventional Flowsheets
HKBR
Primary reformer with manifold/riser
Haldor Topse
Side fired reformer
Radial flow converter
S-200
S-250
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Other Flowsheet Options
Braun Purifier
ICI AMV
ICI LCA
Dual Pressure Uhde Process
HKBR KAAP (with/without purifier)
Linde LAC H2 Recovery is used on most
modern plants
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Braun Purifier Process
Primary reformer exit temperature is 700C
Excess air is added to the secondary reformer
Methane slip typically around 2-2.5 mol %
Excess nitrogen (and methane) cryogenicallyremoved downstream of methanator
Also removes water - ammonia synthesis catalystpoison
Improved synthesis lives Can reduce SC ratio to 2.7-3.0
Small primary
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Braun Purifier Process
Cold Box
Purified Syn Gas
Waste Gas
Raw Syn Gas
Feed Effluent Exchangers
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ICI AMV Process
As with Braun - utilizes excess air to secondary
Excess nitrogen is passed to the loop
Loop runs at low pressure (80-110 bara)
Use ICI LP Catalyst (74- Series) Uses a saturator to saturate feed gas
This raises around 50% of the required steam
Can use SC ratio of 2.8
H2Recovery in loop at loop pressure
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ICI LCA Process
Aim at small plant capacities (500 mtpd)
Uses the GHR-Secondary concept
Excess air is utilized to close heat balance
Utilizes an ITS rather than HTS and LTS A saturator for steam raising
A PSA system to remove the CO2 and excess N2
A low pressure loop (80 bara)
A tube cooled converter or Casale converter
No longer actively marketing
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Dual Pressure Uhde Process
PGR Unit
Make up gas
from frontend
H2O
Ammonia from once through conversion
HP-
steam
C.W.NH
3NH3
C.W.
C.W.
C.W.
HP-
steam
NH3 NH3
Off-Gas
Ammonia
fromHP loop
HP
casing
LPcasing
Firstammonia
converter
Secondammonia
converter
Once
through
ammonia
converter
HP-
steam
Note: Molecular
Sieves not shown
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Dual Pressure Uhde Process
Benefits of such a scheme realised at 3,000
mtpd +
Although this is large capacity - all equipment is
proven Note the low pressure converter between stages
of synthesis gas machine
Makes machine smaller Makes loop pipework 24
Uses Comp. J catalyst
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HKBR Purifier and KAAP
Primary
Reformer
Secondary
Reformer
Shift &
CO2Removal
Purifier
CompressionKAAP
Methn
Dryers
Recycle Purge
To Fuel
Feed
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Linde LAC
Key features are
No secondary reformer
Nitrogen is generated cryogenically and
added after a PSA unit
No HTS/LTS - only Isothermal (ITS) shift
No methanation
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Linde LAC
Desulfurization
Primary Reformer
Isothermal Shift
PSA
Nitrogen Unit
Ammonia Synthesis
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Other Flowsheet Options
Use Gas Turbine to drive process aircompressor
Can use effluent as combustion air
Has 16-17% O2and is at 500C
Braun plants
Install pre reformer
HT Retrofit Many other reasons
Remove heat from duct
Uprate plant
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Other Flowsheet Options
Synthesis Gas driers
Reduces H2O in syn gas
H2O is a poison
Activity increases
Ammonia Wash
As per Syn Gas driers
Booster converters Drop load on loop and allow overall output
increase
Quenches in Shifts
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Ammonia Flowsheet Data Analysis
Tool - VULCAN CERES Looks at all catalytic unit operations
Highlights potential issues/in-correct data
items
Functionality to address flowsheet options Kellogg risers
Differential flowsheet conditions (Braun)
Use as a basis for
Predictions of future performance
Predictions of new catalyst options
Uprates
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