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

12

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

13

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).