John Pach – Johnson Matthey16th IMPCA 2013 Asian Methanol Conference
Purge gas recovery An attractive scheme for methanol-ammonia co-production
John Pach, John Brightling & Terry Fitzpatrick
Agenda
• Introduction• Methanol plant design
H d• Hydrogen recovery• Ammonia loop design• Advantages• Conclusion
John Pach – Johnson Matthey16th IMPCA 2013 Asian Methanol Conference
Heysham, UK before 1960
Billingham 1970s – 2000s
Ammonia Plants
MethanolPlantsPSA
Hydrogen Loop Purge
Carbon Dioxide
Fuel
John Pach – Johnson Matthey16th IMPCA 2013 Asian Methanol Conference
Co-production with ammonia loop
Ammonia Plants
MethanolPlantsPSA
Hydrogen Loop Purge
Carbon Dioxide
Ammonia Loop
FuelNitrogen
Agenda
• Introduction• Methanol plant design
H d• Hydrogen recovery• Ammonia loop design• Advantages• Conclusion
John Pach – Johnson Matthey16th IMPCA 2013 Asian Methanol Conference
Steam reforming
Fuel
Air
Steam
Steam
Feed
Syngas
CO2
SMR + ATR
Fuel Oxygen
Air
Steam
Steam
Feed
Syngas
John Pach – Johnson Matthey16th IMPCA 2013 Asian Methanol Conference
Typical syngas compositions
Syngas technology R ratio CO/CO2 % CH4
SMR 2.9 2 3SMR+CO2 2.1 2 3SMR+ATR 2.1 3 1GHR+ATR 2.1 2 1Gasifier – coal1 2.05 10 0.5Gasifier - biomass 2.05 5 >5• R ratio – Excess H2 R = ([H2]-[CO2])/([CO]+[CO2])
• CO/CO2 – Heat of reaction/ reactivity
• CH4 – Loop efficiency1 Entrained flow gasifier
Methanol plant hydrogen balance
• Typical SMR with NG feed has 40% excess hydrogen• Hydrogen export• CO2 addition• ATR flowsheets• Fuel• Ammonia
John Pach – Johnson Matthey16th IMPCA 2013 Asian Methanol Conference
Methanol plant hydrogen balance
• Typical SMR with NG feed has 40% excess hydrogen• Ammonia
O ti i d th l l t• Optimized methanol plant• High efficiency ammonia loop• Minimal cross connections/interactions
Hydrogen Recovery System
Scrubbed methanol loop purge
Hydrogen
Methanol Plant
Ammonia Loop
Scrubbed ammonia loop purge
Fuel
Agenda
• Introduction• Methanol plant design
H d• Hydrogen recovery• Ammonia loop design• Advantages• Conclusion
John Pach – Johnson Matthey16th IMPCA 2013 Asian Methanol Conference
Methanol purge gas treatment
• Need to remove• H2O
CO• CO• CO2
• Need to recover hydrogen• PSA• Nitrogen wash
• Need to add nitrogen
PSA
Nitrogen
Methanol Plant
PSA Unit
Ammonia Loop
Scrubbed ammonia loop purge
Fuel
Scrubbed methanol loop purge Hydrogen
John Pach – Johnson Matthey16th IMPCA 2013 Asian Methanol Conference
PSA
AdvantagesN i t
DisadvantagesH d f d 80 90%• No energy requirement
• No feed pre-treatment• Pure hydrogen• Stoichiometric nitrogen requirement
• Hydrogen recovery of order 80-90% so 10-20% is lost to fuel
• Can constrain loop operating pressure, if pressure let down is to be avoided.
Nitrogen
Methanol Plant
PSA Unit
Ammonia Loop
Scrubbed ammonia loop purge
Fuel
Scrubbed methanol loop purge Hydrogen
Nitrogen wash
Nitrogen
Methanol Plant
Ammonia Loop
Scrubbed ammonia loop purge
Fuel
Scrubbed methanol loop purge 3:1 H2:N2
Wet CO2removal
Nitrogen WashDrying
John Pach – Johnson Matthey16th IMPCA 2013 Asian Methanol Conference
Nitrogen wash
AdvantagesH d 99% 10 20%
DisadvantagesAdditi l ifi ti t• Hydrogen recovery >99% 10-20%
more ammonia than with PSA• Operating pressure range
encompasses that of methanol synthesis loops
• Very pure stream of H2 and N2 in the ratio 3:1
• Additional purification steps• Much higher nitrogen requirement than
the PSA scheme larger ASU• Additional utility requirements• The waste gas stream contains the
excess nitrogen• Higher capital cost
Nitrogen
Methanol Plant
Ammonia Loop
Scrubbed ammonia loop purge
Fuel
Scrubbed methanol loop purge 3:1 H2:N2
Wet CO2removal
Nitrogen WashDrying
Agenda
• Introduction• Methanol plant design
H d• Hydrogen recovery• Ammonia loop design• Advantages• Conclusion
John Pach – Johnson Matthey16th IMPCA 2013 Asian Methanol Conference
Ammonia synthesis
Ammonia loop design
• High efficiency loop• virtually inert free
Hi h k• High make-up gas pressure • Small syn gas compressor
• Steam for ammonia loop generated • After the ammonia converters• Fired heater
• Fuel gas from hydrogen recovery system. • Natural gas
• Ammonia steam system is independent of methanol steam system.
• Enhanced reliability
John Pach – Johnson Matthey16th IMPCA 2013 Asian Methanol Conference
Agenda
• Introduction• Methanol plant design
H d• Hydrogen recovery• Ammonia loop design• Advantages• Conclusion
Flexibility
• Whilst some co-production schemes lack the flexibility to adjust ammonia and methanol production to meet local market needs an ammonia loop is very flexiblemarket needs, an ammonia loop is very flexible • Increase ammonia production and reduce methanol
production • Send methanol plant syn gas to ammonia loop via HRU
• Reduce ammonia production for a fixed methanol production rate
• Use methanol purge gas as fuel. p g g• Change both ammonia and methanol rates
• Adjust flow through the reformer
John Pach – Johnson Matthey16th IMPCA 2013 Asian Methanol Conference
Operating costs
Efficiency O & M costs• 30.2 GJ/te product
(7.2Gcal/te) • Hot Middle Eastern climate• Includes ASU• 1MWh = 10.8GJ
• For many plants• No increase in operating
and maintenance staff for over that required for stand alone methanol plant.
• Fewer pieces of equipment to maintainequipment to maintain• reduced turnaround cost.
Comparison with stand alone plants
Stand alone Co-production withPSA
Co-production withNitrogen Wash
Methanol plant Same Same Same
Primary reformer Yes No NoPrimary reformer Yes No No
Secondary Reformer Yes No No
Air compressor Yes No No
HTS & LTS Yes No No
Wet CO2 removal Yes No Much Smaller
Methanator Yes No No
SGD ? No Much smaller
SGC Yes Much smaller Much smallerSGC Yes Much smaller Much smaller
Ammonia loop Yes Much smaller Much smaller
Ammonia refrigeration Yes Smaller Smaller
ASU ? Yes Yes
HRU Small membrane PSA Nitrogen wash
John Pach – Johnson Matthey16th IMPCA 2013 Asian Methanol Conference
Agenda
• Introduction• Methanol plant design
H d• Hydrogen recovery• Ammonia loop design• Advantages• Conclusion
Conclusion
• Johnson Matthey and ThyssenKrupp Uhde offer state of the art designs for dedicated methanol plants, for dedicated ammonia plants and for an ammonia-methanoldedicated ammonia plants and for an ammonia methanol co-production scheme which does not compromise operability or reliability and which possesses excellent plant economics.
• We can assist operators to compare the viability of dedicated production assets with that of a co-production facility and provide whichever technology is the best fit forfacility and provide whichever technology is the best fit for any particular project.
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