16th 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 Matthey
16th IMPCA 2013 Asian Methanol Conference
John Pach – Johnson Matthey
Heysham, UK before 1960
Billingham 1970s – 2000s
Carbon Dioxide
Ammonia
Plants
Methanol
Plants
PSA
Hydrogen
Loop Purge
Fuel
16th IMPCA 2013 Asian Methanol Conference
John Pach – Johnson Matthey
Co-production with ammonia loop
Carbon Dioxide
Ammonia
Plants
Loop
Methanol
Plants
PSA
Hydrogen
Loop Purge
Nitrogen
Fuel
Agenda
•
•
•
•
•
•
Introduction
Methanol plant design
H d
Hydrogen
recovery
Ammonia loop design
Advantages
Conclusion
16th IMPCA 2013 Asian Methanol Conference
John Pach – Johnson Matthey
Steam reforming
Fuel
Steam
Air
Steam
Feed
Syngas
CO2
SMR + ATR
Fuel
Steam
Air
Steam
Feed
Syngas
Oxygen
16th IMPCA 2013 Asian Methanol Conference
John Pach – Johnson Matthey
Typical syngas compositions
Syngas technology
SMR
SMR+CO2
SMR+ATR
GHR+ATR
Gasifier – coal1
Gasifier - biomass
R ratio CO/CO2 % CH4
2.9
2
3
2.1
2
3
2.1
3
1
2.1
2
1
2.05
10
0.5
2.05
5
>5
• R ratio
– Excess H2 R = ([H2]-[CO2])/([CO]+[CO2])
• CO/CO2
– Heat of reaction/ reactivity
• CH4
– Loop efficiency
1
Entrained flow gasifier
Methanol plant hydrogen balance
• Typical SMR with NG feed has 40% excess hydrogen
•
•
•
•
•
Hydrogen export
CO2 addition
ATR flowsheets
Fuel
Ammonia
16th IMPCA 2013 Asian Methanol Conference
John Pach – Johnson Matthey
Methanol plant hydrogen balance
• Typical SMR with NG feed has 40% excess hydrogen
• Ammonia
• Optimized
O ti i d methanol
th
l plant
l t
• High efficiency ammonia loop
• Minimal cross connections/interactions
Scrubbed
methanol
loop purge
Hydrogen
Recovery
System
Methanol
Plant
Hydrogen
Fuel
Scrubbed ammonia loop purge
Agenda
•
•
•
•
•
•
Introduction
Methanol plant design
H d
Hydrogen
recovery
Ammonia loop design
Advantages
Conclusion
Ammonia
Loop
16th IMPCA 2013 Asian Methanol Conference
John Pach – Johnson Matthey
Methanol purge gas treatment
• Need to remove
• H2O
• CO
• CO2
• Need to recover hydrogen
• PSA
• Nitrogen wash
• Need to add nitrogen
PSA
Nitrogen
Scrubbed
methanol
loop purge
Methanol
Plant
PSA Unit
Hydrogen
Fuel
Scrubbed ammonia loop purge
Ammonia
Loop
16th IMPCA 2013 Asian Methanol Conference
John Pach – Johnson Matthey
PSA
Advantages
Disadvantages
•
•
•
•
•
N energy requirement
No
i
t
No feed pre-treatment
Pure hydrogen
Stoichiometric nitrogen requirement
•
Hydrogen
H
d
recovery off order
d 80-90%
80 90%
so 10-20% is lost to fuel
Can constrain loop operating
pressure, if pressure let down is to be
avoided.
Nitrogen
Scrubbed
methanol
loop purge
PSA Unit
Hydrogen
Methanol
Plant
Ammonia
Loop
Fuel
Scrubbed ammonia loop purge
Nitrogen wash
Nitrogen
Scrubbed
methanol
loop purge
Methanol
Plant
Wet CO2
removal
Drying
Fuel
Scrubbed ammonia loop purge
Nitrogen
Wash
3:1 H2:N2
Ammonia
Loop
16th IMPCA 2013 Asian Methanol Conference
John Pach – Johnson Matthey
Nitrogen wash
Advantages
Disadvantages
•
•
•
•
•
Hydrogen
H
d
recovery >99%
99% Æ 10-20%
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
•
•
•
Additi
Additional
l purification
ifi ti steps
t
Much higher nitrogen requirement than
the PSA scheme Æ larger ASU
Additional utility requirements
The waste gas stream contains the
excess nitrogen
Higher capital cost
Nitrogen
Scrubbed
methanol
loop purge
Wet CO2
removal
Methanol
Plant
Drying
Fuel
Scrubbed ammonia loop purge
Agenda
•
•
•
•
•
•
Introduction
Methanol plant design
H d
Hydrogen
recovery
Ammonia loop design
Advantages
Conclusion
Nitrogen
Wash
3:1 H2:N2
Ammonia
Loop
16th IMPCA 2013 Asian Methanol Conference
John Pach – Johnson Matthey
Ammonia synthesis
Ammonia loop design
• High efficiency loop
• virtually inert free
• High
Hi h make-up
k
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
16th IMPCA 2013 Asian Methanol Conference
John Pach – Johnson Matthey
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
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 p
purge
g g
gas as fuel.
• Change both ammonia and methanol rates
• Adjust flow through the reformer
16th IMPCA 2013 Asian Methanol Conference
John Pach – Johnson Matthey
Operating costs
Efficiency
• 30.2 GJ/te product
(7.2Gcal/te)
O & M costs
• For many plants
• Hot Middle Eastern climate
• Includes ASU
• 1MWh = 10.8GJ
• No increase in operating
and maintenance staff for
over that required for stand
alone methanol plant.
• Fewer pieces of
equipment to maintain
• reduced turnaround cost.
Comparison with stand alone plants
Stand alone
Co-production with
PSA
Co-production with
Nitrogen Wash
Methanol plant
Same
Same
Same
Primary 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 smaller
Ammonia loop
Yes
Much smaller
Much smaller
Ammonia refrigeration
Yes
Smaller
Smaller
ASU
?
Yes
Yes
HRU
Small membrane
PSA
Nitrogen wash
16th IMPCA 2013 Asian Methanol Conference
John Pach – Johnson Matthey
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-methanol
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 for
any particular project.