1. Sorption-enhanced hydrogen production for pre-combustion CO2 capture
Ruud van den Brink, Paul Cobden, Paul van Beurden, Jurriaan Boon, Rick Reijers, Steven Kluiters, Jan-Wilco Dijkstra, and Daan Jansen

2. Sorption-Enhanced Reaction Process: Integrated reaction and CO2 adsorption
Coal
Coal
gasification
Gas
Cleaning SE
WGS
GTCC
Power
CO2 H2
Natural
gas
ATR SR SE
WGS
GTCC
Power
CO2 H2
Natural
gas SE
reforming
GTCC
Power
CO2

3. Advantage of SERP: Shifting the equilibrium to the product side
Steam reforming: CH4 + H2O H2 + CO (H = 206 kJ/mol)
Water-gas shift: CO + H2O H2 + CO2 (H = – 41 kJ/mol)
Overall: CH4 + 2 H2O H2 + CO2
CH4 + H2O
H2 +CO +CO2
CH4 + H2O H2
CO2
CO2
CO2
CO2
CO2
catalyst
catalyst
catalyst
CO2
sorbent
catalyst
sorbent
CO2
Ordinary Methane Reforming
Sorption-enhanced Reforming

4. SERP is a batch process H steam steam air natural gas steam CO
2 +
SERP reactor
in adsorption
mode
steam
air
natural gas
gas
turbine
generator
steam
SERP reactor
in desorption
mode
water
knock out CO 2

5. ECN Activities SERP
Thermodynamic and cost efficiencies: lecture Daniel Jansen, Session L-4
Catalyst studies: next presentation
CO2 sorbent research
Lab-scale SERP reactions studies
Reactor modelling

6. Summary of efficiency calculations
Air
Air
GT CC H2
Efficiency (%)
CO2 recovery (%)
Air-ATR SE-WGS
50.4
90.0
SE-reforming
51.6
85.0
Ref. w/o CO2 capture
57.1
0.0
CH4
ATR
CO2
Air
GT CC H2
CH4
CO2
Relatively low efficiency penalty
Steam in reaction mode (S/C) + steam used in regeneration mode (S/CO2) determines the overall efficiency.
In efficiency calculations a S/C = 3 and S/CO2 = 1.8

7. Materials Research – Experimental Apparatus
Experimental conditions
100 ml/min flows
1 – 5 grams sample
1 – 4 bar(a)
Diluted gases
Materials
Commercially available WGS en SMR catalysts
22 wt% K2CO3-Hydrotalcites

8. Presence of steam in sorption step promotes CO2 uptake
0.05
0.1
0.15
0.2
0.25 10 20 30
H2O concentration [vol.%]
q(ads) [mmol/g]
CO2 5%
N2 balance
Flow 100 sccm
T = 400 °C
P = 1 atm
3 g K/HTC

9. Capacity for CO2 of hydrotalcite decreases with temperature
0.05
0.1
0.15
0.2
0.25
q(ads) [mmol/g]
CO2 5%
H2O 30%
N %
Flow 100 sccm
T = 400 °C
P = 1 atm
3 g K/HTC
Structure collapses
Above 500 °C
350
400
450
500
550
Temperature [°C]

10. Conversion Enhancement in Water-Gas Shift Reaction6
CO %
H2O 14.5%
CO2 2.5%
H %
N %
Flow 100 sccm
T = 400 °C
P = 1 atm
3 g K/HTC
cat/ads =1:6 w/w
Breakthrough 5
CO2 4 CO
Concentration [%] 3 2
100%
CO conversion
Equilibrium
CO conversion
(50 %) 1 5 10 15 20
Time [min]

11. Conversion Enhancement in Steam Reforming Reaction
ads
desorption
ads
desorption
ads
desorption
ads
1.0
100%
0.9
90%
CH %
H2O 17.5%
N %
Flow 25 sccm
T = 400 °C
P = 1 atm
3 g K/HTC
cat/ads =1:2 w/w CH 4
0.8
80% CO 2
0.7
Conversion
70%
0.6
60%
0.5
CH4 conversion [%]
50%
, concentration [vol%]
0.4
40%
0.3
30%
0.2
20%
0.1
10%
0.0 0% 50
100
150
200
250
Time [min]
Breakthrough of methane before CO2

12. Reactor Model Modeling Isothermal, isobaric
Langmuir or Freundlich adsorption isotherm
Intrinsic reaction kinetics for SMR and WGS
Linear Driving Force (LDF) for adsorption:

13. Shifting the equilibrium
Methane steam reforming
CH4 + 2 H2O H2 + CO2 4 3
partial pressure (bar)
H2 a nd CO2 2 1
Steam reforming 10 20 30 40 50 60 70 80 90
100
Overall conversion (%)

14. Modeling results: small fraction of bed has zero CO2
0.35
0.5 min
0.3 1
1.5 2
0.25 3 4
0.2 5
loading [mol/kg] 6 7
0.15 8 9 2 CO 10
0.1 11
12.5
0.05 14 16
25 min
0.2
0.4
0.6
0.8 1
Bed position [-]

15. Shifting the equilibrium
Methane steam reforming
CH4 + 2 H2O H2 + CO2
WGS reaction 4 3
partial pressure (bar)
H2 a nd CO2 2
Water gas shift 1
Steam reforming
CO + H2O H2 + CO2 10 20 30 40 50 60 70 80 90
100
Overall conversion (%)

16. Steam to carbon (S/C) ratio: variation of CH4 concentration8
CH to 8.3%
H2O 17.5%
N2 balance
Flow 25 sccm
T = 400 °C
P = 1 atm
3 g K/HTC
cat/ads =1:2 w/w
adsorption
desorption
3.0 g cat g ads 6
CH4
S/C = 2
Concentration [%] 4
S/C = 3 2
S/C = 4
CO2
S/C = 5
S/C = 6 5 10 15 20
Elapsed time [min]
Reaction conditions: 2.9 to 8.3% CH4, 17.5% H2O, bal.% N2, 400°C

17. Conversion Enhancement in Steam Reforming Reaction
ads
desorption
ads
desorption
ads
desorption
ads
1.0
100%
CH %
H2O 17.5%
N %
Flow 25 sccm
T = 400 °C
P = 1 atm
3 g K/HTC
cat/ads =1:2 w/w
0.9
90% CH 4
0.8 CO
80% 2
,CO concentration [vol%]
Conversion
0.7
70%
conversion [%]
0.6
60%
0.5
50% 4
0.4
Long tail in desorption
40% CH 2
,CO
0.3
30% 4 CH
0.2
20%
0.1
10%
0.0 0% 50
100
150
200
250
Time [min]

18. Materials Research – Results
3,5
H2O 29%
N %
Flow 100 sccm
T = 400 °C
P = 1 atm
3 g K/HTC
3,0
2,5
2,0
CO2 flow [ml/min]
1,5
PURAL MG70 with 22 wt% K CO 2 3
1,0
70%
80%
90%
0,5
0,0 10 20 30 40 50 60 70 80
Time [min]
S/CO2 50
100
150
200
250
300
350
400

19. Adsorption isotherm of CO2 on K2CO3-promoted hydrotalcite
2.5
Real-life conditions for e.g. SEWGS in IGCC
2.0
400°C
1.5
Adsorbed CO2 [mmol/g]
500°C
1.0
0.5
Experiments in ECN
Lab-scale set-up
0.0 5 10 15 20 25 30 35
CO2 pressure [atm]

20. Experiment at higher pressures
Equilibrium at 3.5 atm:
45 % CH4 conversion
0.6
CH4 3%
H2O 17.5%
N %
Flow 30 sccm
T = 400 °C
P = 1 & 3.5 atm
3 g K/HTC
cat/ads =1:2 w/w
0.5
0.4
Equilibrium at 1 atm:
55 % CH4 conversion
CO2 and CH4 outlet flow [ml/min]
Breakthrough CO2 10 minutes later at 3.5 bara than at 1 atm
0.3
P = atmospheric
0.2
0.1
P = 2.5 barg
0.0
CH4 breakthrough still after 3 mins at 3.5 atm 20 40 60
Time [min]

21. Conclusions Promoted HTC is suited for SE-WGS.
Sorption-enhanced reforming yields low efficiency penalties
Provided that steam input can be kept low
However, using K2CO3-HTC as sorbent, steam is needed to prevent early breakthrough of methane and for regeneration.
Possible remedies:
At higher pressures regeneration requires less steam
higher temperatures would give better performance and lower steam need
However, above 500°C, CO2 capacity of promoted hydrotalcite decreases strongly.

22. Future work Sorption-enhanced reforming High-temperature sorbents
Experiments at higher pressures (10 to 40 bar(a)) and less diluted gases
Sorption-enhanced Water Gas Shift
CACHET project (EU FP6 & CCP-2)
Collaboration with Air Products
2 meter high bed SEWGS PDU
Multiple 6 meter high beds Proof-of-Concept unit

23. Acknowledgement
CATO is the Dutch national research programme on CO2 Capture and Storage. CATO is financially supported by the Dutch Ministry of Economic Affairs (EZ) and the consortium partners. (