The document discusses various aspects of ammonia production processes including: 1) Simplified block diagrams of typical ammonia, methanol, and hydrogen production plants showing the main process units. 2) Modern conventional ammonia plant flowsheets have the same main process steps but differ in equipment designs between vendors. 3) Other flowsheet options for ammonia production including the Braun Purifier process, ICI AMV, ICI LCA, dual pressure Uhde process, and Linde LAC process. 4) Additional process modifications and options such as gas turbine drives, pre-reformers, heat recovery techniques, synthesis gas driers, and booster converters.

1. Ammonia
Basic Flowsheet Elements

2. Chemistry of the Ammonia Process

3. Simplified Block Diagram of a Typical
1000 t/d Ammonia Plant

4. Simplified Block Diagram of a 2000
MTPD Methanol Flowsheet
Methanol
Purification
Reforming
Compression Distillation
Synthesis
Steam Raising
Feedstock
(CH )
4
Water
VHT-S103
20 m³
VSG-EZ200
VSG-Z101
40 m³
VSG-Z101
40 m³
VSG-A101
200 m³

5. 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

6. Simplified Flowsheet for a Typical
Ammonia Plant
Natural
Gas
Steam
superheater
Air
Steam
30
bar
Steam
Steam
raising
350 C
200 C
Heat
Recovery
Steam
raising
Cooling
Cooling
Reboiler
CO
Cooling
Preheater
Heat
Recovery
Steam
Boiler
Process
Condensate
Quench
Quench
Liquid Ammonia
H
Hydrodesulphuriser Primary
Reformer
Secondary
Reformer
High
Temperature
Shift
Low
Temperature
Shift
Ammonia SynthesisMethanator
Carbon Dioxide
Purge Gas
Cooling
400 Co
390 Co
2
790 C
o
550 Co
1000 Co
o
420 Co
150 C
o
400 Co
470 C
o
o
220 C
o
290 Co
330 Co
2
CO Removal2
220 bar
Refrigeration
Condensate
Cooling
Ammonia
Catchpot

7. 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

8. Modern Conventional Flowsheets
 HKBR
 Primary reformer with manifold/riser
 Haldor Topsøe
 Side fired reformer
 Radial flow converter
 S-200
 S-250

9. 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

10. Braun Purifier Process
 Primary reformer exit temperature is 700°C
 Excess air is added to the secondary reformer
 Methane slip typically around 2-2.5 mol %
 Excess nitrogen (and methane) cryogenically
removed downstream of methanator
 Also removes water - ammonia synthesis catalyst
poison
 Improved synthesis lives
 Can reduce SC ratio to 2.7-3.0
 Small primary

11. Braun Purifier Process
Cold Box
Purified Syn Gas
Waste Gas
Raw Syn Gas
Feed Effluent Exchangers

12. 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
 H2 Recovery in loop at loop pressure

13. 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

14. Dual Pressure Uhde Process
PGR Unit
Make up gas
from frontend
H2O
Ammonia from once through conversion
HP-
steam
C.W.NH3
NH3
C.W.
C.W.
C.W.
HP-
steam
NH3 NH3
Off-Gas
Ammonia
from
HP loop
HP
casing
LP
casing
First
ammonia
converter
Second
ammonia
converter
Once
through
ammonia
converter
HP-
steam
Note: Molecular
Sieves not shown

15. 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

16. HKBR Purifier and KAAP
Primary
Reformer
Secondary
Reformer
Shift &
CO2
Removal
Purifier
CompressionKAAP
Meth’n
Dryers
Recycle Purge
To Fuel
Feed

17. 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

18. Linde LAC
Desulfurization
Primary Reformer
Isothermal Shift
PSA
Nitrogen Unit
Ammonia Synthesis

19. Other Flowsheet Options
 Use Gas Turbine to drive process air
compressor
 Can use effluent as combustion air
 Has 16-17% O2 and is at 500°C
 Braun plants
 Install pre reformer
 HT Retrofit
 Many other reasons
 Remove heat from duct
 Uprate plant

20. 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

21. 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