HYDROGEN PRODUCTION FROM NATURAL GAS WITH VERY LOW … · cycle CO. 2. separation Compression...
Transcript of HYDROGEN PRODUCTION FROM NATURAL GAS WITH VERY LOW … · cycle CO. 2. separation Compression...
HYDROGEN PRODUCTION FROM NATURAL GAS WITH VERY LOW CO2INTENSITY
Julian Straus, Vidar Skjervold,Rahul Anantharaman, David Berstad
Overview
• Natural gas reforming – process description
• Recap: Improved process configuration
• CO2 liquefaction as separation technology
• Analysis of operation conditions
• Comparison to aMDEA + PSA process
• Conclusion
2
Natural gas reforming
3
• Hydrogen separation technologies:• Pressure swing adsorption
(PSA)
• Palladium membrane(Pd)
• Focus on:• Recap of last results
Combustor
Pre-reformer
Water-gas shiftsection
Hydrogenseparation
Natural gasfeedstock
Shiftedsyngas
Auto-thermal reformer
O2
Tail gas tocombustor
CO2
Cryogenic air separation
Exhaust
O2 compression
Tail gasrecycle
Hydrogento liquefiers CO2
liquefaction
Natural gas reforming
4
• Hydrogen separation technologies:• Pressure swing adsorption
(PSA)
• Palladium membrane(Pd)
• Focus on:• Recap of last results
• Improvements for CO2
liquefaction while maintaining similar CO2 capture rate
Combustor
Pre-reformer
Water-gas shiftsection
Hydrogenseparation
Natural gasfeedstock
Shiftedsyngas
Auto-thermal reformer
O2
Tail gas tocombustor
CO2
Cryogenic air separation
Exhaust
O2 compression
Tail gasrecycle
Hydrogento liquefiers CO2
liquefaction
Recap: New process conditions
5
LT-LCO2 + Pd
LT-LCO2 + PSA
CO2 liquefaction
• Process for simultaneous separation and liquefaction of CO2
• Costs of separation characterized by• Feed stream composition
6
Heat integrationCompression
From H2separation
Refrigeration cycle
CO2 separation
Compression
Liquid CO2
Tail gas
CO2 liquefaction
• Process for simultaneous separation and liquefaction of CO2
• Costs of separation characterized by• Feed stream composition
• Separation conditions (p and T)
7
Heat integrationCompression
From H2separation
Refrigeration cycle
CO2 separation
Compression
Liquid CO2
Tail gas
CO2 liquefaction
• Process for simultaneous separation and liquefaction of CO2
• Costs of separation characterized by• Feed stream composition
• Separation conditions (p and T)
8
Heat integrationCompression
From H2separation
Refrigeration cycle
CO2 separation
Compression
Liquid CO2
Tail gas
• Heat integration
• Refrigeration cycle performance
Impact of separation conditions
9
Heat integrationCompression
From H2separation
Refrigeration cycle
CO2 separation
Compression
Liquid CO2
Tail gas
LT-LCO2 + Pd
LT-LCO2 + PSA
Impact of separation conditions
10
Heat integrationCompression
From H2separation
Refrigeration cycle
CO2 separation
Compression
Liquid CO2
Tail gas
Pd membrane Pressure Swing Adsorption
Refrigeration cycle performance
11
Heat integrationCompression
From H2separation
Refrigeration cycle
CO2 separation
Compression
Liquid CO2
Tail gas
• Performance depending on distribution of cooling duties
• Different feed conditions result in different performance improvements
• Potential for further improvement through rigorous optimization
Comparison to aMDEA-PSA technology
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84.7
78.0
83.6
50
90
80
70
60
Effic
ienc
y HH
V [%
]
96.1
92.7
96.4
80
95
90
85CO2
capt
ure
rate
[%]
9.3
17.4
8.7
0
15
10
5
CO2
inte
nsity
[g C
O2/
kWh L
HV]
*Without CO2
from power and upstream natural gas emissions
aMDEA + PSA
LT-LCO2 + Pd
LT-LCO2 + PSA
Comparison to aMDEA-PSA technology
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aMDEA + PSA
LT-LCO2 + Pd
LT-LCO2 + PSA
89.1
100
89.9
85
95
90
Rela
tive
volu
met
ric fl
owra
te N
G [%
]
• Improved performance through:• Reduced natural gas demand
• Increased carbon capture ratio
• Novel process layout (to be published in a paper)
• Requires however more external power through lower power generation
14.4
-21.
8
21.6
-25
20
0-5
Net
pow
er d
eman
d [W
h/ k
Wh L
HV]
-10-15-20
1510
5
Conclusion
• Natural gas reforming with carbon capture has potential for:• Very low CO2 intensity of hydrogen
• High efficiencies independently of the hydrogen separation technology
• Liquefaction of CO2 as separation technology:• Relatively new technology with further potential for improved performance above the
achieved 20 % reduction in energy consumption
• Based on widely applied unit operations
14
15
Acknowledgements
This publication is based on results from the research project Hyper, performed under the ENERGIX programme. The authors acknowledge the following parties for financial support: Equinor, Shell, Kawasaki Heavy Industries, Linde Kryotechnik, Mitsubishi Corporation, Nel Hydrogen, Gassco and the Research Council of Norway (255107/E20).