This document discusses different types of methanol synthesis reactors, including quench converters, ARC converters, tube cooled converters, and adiabatic bed reactors. It provides details on the benefits and drawbacks of each type, such as the quench converter being simple and reliable but prone to temperature maldistribution issues across the catalyst beds. The document also examines techniques for improving reactor design and operation, such as the ARC retrofit developed to improve gas mixing in quench converters.

1. Gerard B. Hawkins
Managing Director

2. • Quench Converter
• ARC Converter
• Tube Cooled
• Toyo MRF-Z
• Adiabatic Beds

3. Exit
Catalyst
Discharge Chute
Catalyst
Discharge Chute
Manway
Manway
Inlet
Inert Balls

5. Vessel Wall
Shot Pipe
Sparge Pipe
Sparge
Holes
Mesh

6. 180 200 220 240 260 280 300 320
0
2
4
6
8
10
Temperature (°C)
MethanolConcentration(mol%)
Max Rate
Curve
Methanol
Equilibrium

7. MUG
Flash Drum
Separator

8. • Benefits are
◦ Simple
◦ Reliable
◦ Well proven
◦ Capacity up to 3000 mtpd
• Recover heat into saturator circuit
• The catalyst doesn’t see all the gas.
• Poor catalyst loading can lead to cold core
developing

9. • Significant flow mal-distribution
• Some zones are cold
◦ Can lose reaction
• Some zones are hot
◦ High byproducts levels
◦ High rate of catalyst deactivation

10. Cool NormalNormal
Catalyst density
Low
flow

11. • It is not caused by the quench lozenges being
poor distributors of the cool incoming gas.
• The reverse is true - the lozenges are very good
distributors.
• The problem is that voidage variations across the
bed can cause varying flows down different parts
of the reactor.
• ARC retrofit developed to overcome problem.

12. Catalyst Support
Plates Individual / Separate
Catalyst Beds
Gas Mixing
System

13. x x xx x x x xx x x xx x x x xx x x x xx x x x xx x x x xx x x x xx x x x xx x x x xx x x xx x x x xx x x x xx x
C a t aly s t be d

14. Inlet Temperature Exit Temperature
Bed 3 237 °C
Bed 1 223 °C
Bed 4 230 °C
Bed 3 270 °C
Bed 1 270 °C
Bed 2 223 °C
Bed 4 260 °C
Bed 2 270 °C
Bed 3 261 °C
Bed 1 251 °C
Bed 4 269 °C
Bed 3 289 °C
Bed 1 291 °C
Bed 2 262 °C
Bed 2 301 °C
* Figures in red are from current
operating records (Sept. '96)
* Figures in black are from ARC
design case

15. Temperature
% Methanol
Equilibrium
Line
Quench Converter
ARC Converter
Increase in
Methanol %

16. 0 10 20 30 40 50
0
50
100
150
200
temperature stand. dev. °C
%increaseinby-products

17. QCC + ICI 51-7 ARC + ICI 51-7
Ethanol 200 69 ppm
Propanol 71 28 ppm
Butanol 71 33 ppm
MEK 13 <5 ppm
Decane C10 2.6 0.9 ppm
Undecane C11 1.8 0.6 ppm
Dodecane C12 1.2 0.4 ppm
Tridecane C13 0.7 0.3 ppm
Comp A Comp A

18. 0 200 400 600 800 1,000 1,200 1,400
1,400
1,450
1,500
1,550
1,600
1,650
Days on line
Production(te/day)

19. Key features
improved gas mixing
no penalty on pressure drop
better utilisation of the converter volume
minimise the by-product levels

20. Arc Revamp
Catalyst Loading
Lozenge removal
Converter inspection
Fit ARC internals
Catalyst loading
Bed 5
Bed 4
Bed 3
Bed 2
Bed 1
0 7 14 21
activity
days

21. • ARC converters have exhibited an instability
• This is highlighted by inlet and outlet temperatures
varying as per a sine wave
• Feedback occurs over warm loop interchanger
• Normally stable but can become unstable
◦ Leads to loss of strike in converter
• Action is to reduce circulation rate

22. Manway
Outlet
Manway
Inlet
Catalyst
Discharge Port

23. Heat Recovery
Unit
Crude
Crude
Cooler
Loop
Interchanger
Syn Gas
Purge

24. 180 200 220 240 260 280 300 320
0
2
4
6
8
10
Temperature (°C)
MethanolConcentration(mol%)
Max Rate
Curve
Methanol
Equilibrium

25. • Cheaper loop with heat transfer and reaction
• Smooth catalyst temperature profile
• Good catalyst utilisation
• Mechanically simple
• All converter effluent available at high temperature
◦ Can be used to heat saturator water

26. • Mixing shall be effective
• Mixer should
◦ either not impede loading
◦ or be easy to install and remove.
• Mixer should enhance safe operation and be
mechanically robust.
• Leakage of gas bypassing mixer should be
minimized.

28. Steam Outlet
Central Pipe
Catalyst Loading
Gas Inlet
Gas Outlet &
Catalyst Unloading
BFW Inlet
Cooling
Tube
Catalyst
Inert Balls

29. Outlet Collector
Scallops Adiabatic Beds
Cooled Bed
Cooling Tube

30. 180 200 220 240 260 280 300 320
3
4
5
6
7
8
9
10
Temperature (°C)
MethanolConcentration(mol%)
Max Rate
Curve
Methanol
Equilibrium

31. • 28-32 Bara steam raised
• Good approach to equilibrium
• Low pressure drop, 0.5 to 0.75 bar
• Catalyst discharge complex
• Small number of tubes (c.f. Lurgi converter)

33. Crude
Crude
Cooler
Loop
Interchanger
Syn Gas
Purge
Steam

34. 180 200 220 240 260 280 300 320
0
2
4
6
8
10
Temperature (°C)
MethanolConcentration(mol%)
Max Rate
Curve
Methanol
Equilibrium

35. • Cross flow means high heat transfer coefficient
◦ Smaller surface area
• Good utilisation of shell volume
• Raised steam at between 30-40 bara
• But
◦ Costly (not as expensive as Uhde/Lurgi)
◦ Large interchanger required
◦ Pressure is slightly lower than Uhde/Lurgi

36. Casale
Horizontal Adiabatic Converter

37. 180 200 220 240 260 280 300 320
0
2
4
6
8
10
Temperature (°C)
MethanolConcentration(mol%)
Max Rate
Curve
Methanol
Equilibrium

38. • All the gas sees all of the catalyst
• Cheap vessels - can be spherical
• Vessels can be designed the same
◦ Reduces CAPEX
• But
◦ Large loop interchanger
◦ Multiple vessels (excluding Casale’s Horizontal
Converter)
◦ Beds are shallow and so mal distribution can be a
problem

39. Relative Catalyst Volumes
Base Case 2800 te/day plant (Chile 3)
Fixed circulation rate (recycle ratio = 4.2)
Reactor Catalyst Volume (m3)
ARC 242
TCC 175
SRC 150

40. • Loop pressurised to 7 bar with nitrogen
• Heated to 180°C
• Add small amount of H2 for calibration
• Heat to give peak temperature of 220°C
• Add hydrogen to 2%
• Monitor temperatures
• When exotherm profile moves through bed start
soak
• Increase H2 and temperature

41. • Similar to Reduction
• Use air instead
• Again exothermic
• Also requires soak
• Can not fully guarantee full oxidation
• Procedure is available

42. Process Information Disclaimer
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supplied to Users is believed to be accurate and correct
at time of going to press, and is given in good faith, but it
is for the User to satisfy itself of the suitability of the
Product for its own particular purpose. GBHE gives no
warranty as to the fitness of the Product for any
particular purpose and any implied warranty or condition
(statutory or otherwise) is excluded except to the extent
that exclusion is prevented by law. GBHE accepts no
liability for loss or damage resulting from reliance on this
information. Freedom under Patent, Copyright and
Designs cannot be assumed.