2. Methanol is the simplest of the series of
aliphatic alcohols. It is an extremely versatile
chemical and is used as a raw material for a
number of processes in the chemical industry.
It may also be used unchanged as a solvent or
cleaning fluid. Its largest single usage is
oxidation to formaldehyde, itself a raw material
used in the manufacture of synthetic resins for
the wood, plastics, and paint industries.
Methanol
7. Benefits of Lurgi Steam Raising
Converter
Catalyst is on the tube side
Optimized heat transfer area / catalyst volume
Isothermal
Mechanically complex
Requires integration into the steam system
Steam raised at a higher pressure than Adiabatic
Bed Converters
9. Comparison of Tube Cooled,
Linde and Lurgi Converters
25
mm
25
mm
25
mm
Tube diameter 30 mm 10 mm 50 mm
Tube pitch 70 mm 52 mm 100 mm
Cat. vol/tube area 37 mm 72 mm 12.5 mm
Volume utilised 83% 97% 23%
TCC Linde Lurgi
10. Comparison of Linde and Lurgi
Converters
Linde converter has less heat transfer area
• Therefore cheaper
Small catalyst operates along the maximum rate curve
therefore converter smaller
Linde can achieve 2000 tpd in one vessel
• Older Lurgi plants of 1000+ mtpd tend to have 2 converters
Linde simple to manufacture
• Lurgi complex - tube sheet limits size of converter
11. Comparison of Linde and Lurgi
Converters
In Linde SRC gas flows across tubes
• Lurgi down inside tubes
Linde converter easy to load
• Lurgi SRC has top have each tube loaded
individually
Must check pressure drops are equal as with a
reformer
• Many tubes - 5000 per converter
12. Linde & Lurgi SRC's
Compared to Toyo MRF
Linde/Lurgi SRC's can raise steam at 35 to 40
bara
• Toyo MRF can raise steam at 28 to 32 bara
• Both can be used in reformer
Toyo MRF catalyst runs at higher temperature
• Catalyst will deactivate slightly faster
Toyo MRF is Radial flow
• Low converter pressure drop
13. There have been a number of instances where the
welds between the tubes and the bottom
tubesheet have failed
During normal operation this is not a problem for
the process side
Syn gas does enter the steam system
On shut down the reverse happens leading to
catalyst damage
14. Some plants have reported high pressure
drops across the catalyst in Lurgi converters
Why ?
◦ Boiler Feed Water leaks
◦ Crushing of catalyst on start up and shut downs
Catalyst is weak
No clear reason
17. Click here to type slide reference
BFW
MP Steam
BFW
Cold Water
Natural
Gas
Refining Column Bottoms
HP Steam
Fuel Gas
Hot
Water
Air
MP Steam
C/W
Product Methanol
Fusel Oil
C/W
Secondary
Oxygen
18. Click here to type slide reference
WHB
Air
MP Steam
Product Methanol
Fusel Oil
Natural Gas
Purification
BFWSteam
Converter
Purge to Fuel
Expander
C/W
C/W Refining Column Bottoms
Steam
Drum
22. Mitsubishi Superconverter Benefits
Integration of interchange and steam raising
Complex converter consisting
• large number of tubes, a manifold, two tube sheets
• i.e. the worst features of a Lurgi SRC and a TCC
Closely follows maximum rate line
• High conversion per pass - low recycle rate
Raises 40 bar steam
24. Click here to type slide reference
MP Steam
Natural Gas
LP Steam
BFW
Air
BFW to
D/A
BFW
C/W
Process CondySteam
Raising
Steam
Raising
BFW
Heating
Purge to Fuel
Crude Fusel Oil
Product Methanol
Refining Column Bottoms
Fuel
HP
Steam
BFW
C/W
C/W
25. Multiple Adiabatic Bed Converters
Different designs
Typically multiple beds in multiple vessels
• Can be in one vessel
Separate vessels for each bed
Intercooling between beds
• BFW and steam raising
26. Multiple Adiabatic Bed Converters
30 bara steam raised and some BFW heating
Vessels are cheap to manufacture as the walls
are thin and all are same
Large pipe size to minimize pressure drop
More expensive than a quench converter due to
pipework costs
Jagged temperature profile
Large number of equipment items
Beds can be shallow; mal-distribution can be an
issue
Large loop interchanger
27. Adiabatic Bed Converter Equilibrium
Profile
180 200 220 240 260 280 300 320
0
2
4
6
8
10
Temperature (°C)
MethanolConcentration(mol%)
Max Rate
Curve
Methanol
Equilibrium
28. Click here to type slide reference
BFW
Purge to
Fuel
C/W
BFW
Purification
HP Steam
Air
Fuel
Natural Gas
Product Methanol
Fusel Oil
Refining Column Bottoms
C/W
Preheated
Fuel
Preheated
Air
BFW