The document summarizes research on sorption-enhanced steam reforming of ethanol (SE-SRE) for hydrogen production. The key points are: 1) Preliminary investigations identified reaction pathways and kinetics for SRE on Ni/Al2O3 catalyst. Thermodynamic modeling determined optimal steam-to-ethanol ratios to maximize hydrogen yield while minimizing carbon deposition. 2) Initial experiments on SE-SRE used Ni/Al2O3 catalyst and hydrotalcite sorbent, achieving high purity hydrogen. Further work developed Cu-based catalysts to prevent carbon deposition and hybrid catalyst-sorbent materials. 3) K-promoted hydrotalcite was synthesized and showed higher CO2 sorption

1. Departamento de Engenharia Química
Rua Dr. Roberto Frias, S/N | 4200-465 Porto| Portugal lsre@fe.up.pt
http://lsre.fe.up.pt
Sorption-Enhanced Steam Reforming
of Ethanol for Hydrogen Production
By: Yi-Jiang Wu
Supervisor: Prof. Alirio E. Rodrigues
Co-advisor: Dr. Adelino F. Cunha
11 July 2014

2. Outline
Background
Objectives
Preliminary Investigation
Material Development
Process Study
Conclusions and Future Work
1

3. 1. Background
Hydrogen
Clean
– Low environmental impact
High energy density
– 120.7 kJ/g
High efficiency
– Hydrogen fuel cell
Production
– Electrolysis
– Photobiological
– Water-gas-shift
– Steam reforming
• (natural gas, bio-ethanol...)
*U.S. Department of energy, http://www.hydrogen.energy.gov/
Figure 1. The integration of a hydrogen economy.*
2

4. 1. Background
Standard methane reforming process
– High temperature reaction
• energy supply, construction material, catalyst deactivation
– Purification
• H2 purity, H2 recovery
3
Harrison, Ind. Eng. Chem. Res., 2008, 47, 6486–6501.
Reforming
Reactor
CH4/H2O
Feed
Flue gas
WGS
Reactor
PSA
units
99.5 + % H2
CO2
absorption
Methanator
or PROX
95 + % H2
Trace CO,CO2
PSA Off-gasFuel/Air
Reaction Purification
CH4+H2O⇌CO+3H2 CO+H2O⇌CO2+3H2

5. 1. Background
Sorption-enhanced reaction process (SERP)
– Le Chatelier’s principle
Old and new
– Concept proposed in 1868*
– SERP named in 1996**
4
CH4 g + 2H2O g
catalyst
4H2 g + CO2(g) CH4 g + 2H2O g
catalyst and sorbent
4H2 g + CO2 ∙ sorbent(s)
Reaction
Catalyst
CO2
Sorbent
CH4 + H2O CO2
H2
H2
H2
CO2
CO2
CO2
CO2
H2
CO2
C2H6O + H2O
6CO2+12H2O
Photosynthesis
ΔH0 = +2540kJ/mol
ΔG0 = +2830kJ/mol
C6H12O6+6H2O
Distillation & Combustion
(Low efficiency)
Fermentation
ΔH0= +20 kJ/mol
ΔG0= -210 kJ/mol
Hydrogen Fuel Cell
ΔH0= -2904 kJ/mol
ΔG0= -2748 kJ/mol
Steam Reforming
ΔH0= +344 kJ/mol
ΔG0= +128 kJ/mol
2CO2+2C2H5OH+6H2O
6CO2(s)+12H2
6O2
* Motay et al., Bull. Soc. Chim. Fr., 1868, 9, 334.
** Sircar et al., AICHE J., 1996, 42(10), 2765-2772.

6. 2. Objectives
High purity hydrogen production from ethanol at
intermediate temperature (673 K – 773 K)
Sorption-enhanced steam reforming of ethanol (SE-SRE)
Materials requirements:
– Catalysts
• activity, selectivity and stability
– Sorbents
• capacity, selectivity, kinetics, regeneration and stability
Numerical simulation for improvement
– Reaction condition
– Operating parameter
5
H2O,
C2H5OH
H2, H2O
Catalyst
Sorbent
22 5 2 2( ) 3 ( ) 2( ( )6 )catalyst
sorbent
C H OH g CO Sorbent sH O g H g   

7. 3. Preliminary Investigation
Experimental setup
He N2 H2 CO2
Mass
Spectrometer
Vent
1
2
3
54
6
7
8 9
Figure 1 Schematic and picture of the experimental unit: (1) feeding
gases; (2) mass-flow controllers; (3) feeding mixture; (4)
pump for liquids; (5) mixing valve; (6) reforming reactor; (7)
heating furnace; (8) back pressure valve; (9) mass
spectrometer.
6

8. Ethanol Acetaldehyde
Dehydrogenation
Hydrogen
Steam Methane Reforming
Dehydration
Coke
Ethane
Dehydrogenation Steam Ethylene Reforming*
Ethylene
Boudouard Reaction
Methane Decomposition
Water Gas Shift
Carbon monoxide
4 22CH C H 
2 2C CO CO 
2 2 2CO H O CO H  
4 2 6 22CH C H H 
4 2 23CH H O CO H  
4 2 2 22 4CH H O CO H  
2 2C H O CO H  
2 4 2
1
2
C H C H 
3 2 2 4 2CH CH OH C H H O 
Methane
3 4CH CHO CH CO 
Decomposition
3 2 4 2CH CH OH CH CO H  
3 2 3 2CH CH OH CH CHO H 
Decomposition
2 6 2 4 2C H C H H 
Ethylene
Polymerisation
Coke Gasification
Steam Ethane Reforming**
3. Preliminary Investigation
Reaction pathway for steam reforming of ethanol (SRE)
– Reaction conditions
• temperature, pressure, steam-to-ethanol molar ratio (RS/E)…
– Catalysts compositions
• active metal, support, structure…
7
Wu et al., Can. J. Chem. Eng., 2014, 92 (1), 116-130.

9. 3. Preliminary Investigation
Reaction mechanism on Ni/Al2O3(Degussa 1001)
– Langmuir-Hinshelwood Hougen-Watson (LHHW)
Reaction kinetics
– Power-rate law and LHHW expressions
8
0 1 2 3 4 5
0
8
16
24
32
40
pEtOH
[kPa]
473 K
573 K
673 K
773 K
873 K
rSRE
[mol·kg-1
h-1
]
Figure 2 Kinetic model vs. Experimental results
(filled spots) at ptotal = 1 bar with a RS/E of
10 in the feed. Power rate model (dashed
lines); LHHW model (solid lines).
Wu et al., Can. J. Chem. Eng., 2014, 92 (1), 116-130.

10. 3. Preliminary Investigation
Thermodynamic analysis
– Gibbs free energy minimization
– Real gas vs. ideal gas for SRE
• Virial model
– Steam-to-ethanol (RS/E) molar ratio
• Carbon deposition
• Hydrogen yield
9
SRE (real gas) SRE (ideal gas)
T XH2O YH2 YCO XH2O YH2 YCO
K % mol/molEtOH % mol/molEtOH
773 12.7 5.21 0.11 13.6 5.48 0.06
Table 1. Equilibrium of SRE at 100 kPa, H2O/Ethanol = 20 [mol/mol]
Wu et al., Chem. Eng. Technol. 2012, 35 (5), 847-858.
min 1 2( , , , ,... )NG G T p n n n
500 600 700 800 900
4
6
8
10
12
14
16
18
20
YH2
[mol/molEtOH,0
]
T [K]
0.0
0.4
0.7
1.4
2.1
2.8
3.4
4.0
4.4
4.9
5.2
5.5
5.8
6.0
b)
RS/E
[mol/mol]
Figure 3 The effects of steam-to-ethanol ratio on
carbon deposition (a) and hydrogen yield (b).
500 625 750 875 1000 1125 1250
0
1
2
3
4
5
H2
yield
Carbon deposition
3
2.5
2
1.5
1
0.5
0
3 2.5
2
1.5 1
0.5
Y[mol/molEtOH,0
]
T [K]
0
RS/E
a)

11. 3. Preliminary Investigation
High temperature CO2 sorbent
– SE-SRE reaction performance
– Hydrogen product with HTlc
• High purity > 99 mol %
• CO content < 30 ppm
• Direct fuel cell application
10
Wu et al., Chem. Eng. Technol. 2012, 35 (5), 847-858.
CaO Li2ZrO3 HTlc
T
[K] [mol %] [ppm] [mol %] [ppm] [mol %] [ppm]
773 84 915 78 1460 99 11
Figure 4 CO2 adsorption Li2ZrO3 (a) and HTlc (b).
2Hy COy COy COy2Hy 2Hy
Materials Capacity Stability Kinetics
CaO Good Poor Fair
Li2ZrO3 Fair Good Poor
Hydrotalcite (HTlc) Poor Good Good
Li2ZrO3
Adsorption at
773 K
Li2ZrO3
ZrO2
Li2CO3
(Solid)
Li2ZrO3
Li+
ZrO2 Shell O2-
Li2CO3 Shell
co2
ZrO2 ZrO2ZrO2
Desorption at
1053 K
Li2CO3
(Liquid)
Li+
CO2 O2-
Li2ZrO3
ZrO2
Li2ZrO3
co2
a)
b)
Table 2 Equilibrium of SE-SRE at 100 kPa, H2O/Ethanol = 20 [mol/mol].

12. 3. Preliminary Investigation
Sorption enhanced reaction performance
– Ni/Al2O3 catalyst (Degussa 1001)
– Hydrotalcite sorbent (Sasol MG30)
Figure 5 Product distribution vs. Reaction time.
Reaction conditions: T = 673 K; p = 100 kPa;
RS/E = 10; mcat = 4×1.25 g; msorb = 3×25.0 g.
H2O,
C2H5OH
H2, H2O
Nickel-based
Catalyst
(1001)
Hydrotalcite
Sorbent
(MG30)
11
Cunha et al., Can. J. Chem. Eng. 2012, 90(6), 1514-1526.
He N2 H2 CO2
Mass
Spectrometer
Vent
0 10 20 30 40 50 60
0
20
40
60
80
100
yCO
[mol%]
yH2
,CH4
,CO2
[mol%]
t [min]
H2
CO2
CH4
CO 0
1
2

13. 4. Material Development
Compatibility of catalyst and sorbent
– Layered system
– Ideal mixture
– Hybrid material
H2
Catalyst (active phase)
H2C2H5OH/CH4
H2O
Adsorbent
H2 Yield CO2 Yield
H2C2H5OH/CH4
H2O
C2H5OH/CH4
H2O
Cunha et al., Chem. Eng. Res. Des., 2013, 91(3), 581-592.
12

14. 4. Material Development
Deactivation due to the carbon deposition
– Ni-based catalyst at high temperature
Cu-based catalysts for dehydrogenation
– Avoid carbon deposition
Cu-Catalyst
H2C2H5OH, H2O
Adsorbent
C2H4O, H2O
CH4, H2,COX
Ni-Catalyst
1st
Layer 2nd
Layer
Ni-catalyst polymerisation
2 5 2 2 4high-temperature
CarbonC H OH H O C H  
Cu-catalyst Ni-catalyst
2 5 2 2 4 4C H OH H C H O CH CO   
P. D. Vaidya, A. E. Rodrigues, Chem. Eng. J., 2006, 117(1), 39-49.
13
Cunha et al., Chem. Eng. Res. Des., 2013, 91(3), 581-592.

15. 4. Material Development
Preparation of the hybrid materials
14
HTlc
Solution of
Ni(NO3)2 or Cu(NO3)2
Impregnation
Dried at 383 K
overnight
Calcination and reduction at
higher temperature (548 - 723 K)
Cu-HTlc / Ni-HTlc materials

16. SE-SRE with Cu (5 wt. %) and Ni (6 wt. %)-HTlc materials
– High purity H2 during initial period
– Low CO2 sorption capacity
• ~ 0.15 mol/kg…
4. Material Development
15
Figure 6 Product distribution on dry basis as function of reaction time on Cu-HTlc material (a) and Ni-HTlc
material (b) at 773 K, p = 101.3 kPa with a RS/E of 10 in the feed.
Wu et al., Chem. Eng. J.,2013, 231, 36-48.
Cunha et al., Chem. Eng. Res. Des., 2013, 91 (3), 581–592.
0 600 1200 1800 2400 3000
0
15
30
45
60
yH2
[mol%]
t [s]
H2
CO2
CH4
CO
b)Ni-HTlc Material for SE-SRE
yCO,CH4
,CO2
[mol%]
0
20
40
60
80
100
0 600 1200 1800 2400 3000
0
5
10
15
20
25
30
yH2
[mol%]
t [s]
H2
CO2
CH4
CO
a)Cu-HTlc Material for SE-SRE
yCO,CH4
,CO2
[mol%]
50
60
70
80
90
100

17. 4. Material Development
K-promoted (20 wt. %) HTlc with KNO3 as K precursor
– Impregnation
• MG30 hydrotalcite + KNO3, Ultrasonic 6h, 110 ºC 24h
– Calcination
• 2KNO3 → K2O + O2 + NO + NO2, 485 ºC 48h
K-promoter effect**
O Mg K
16
0.0
0.2
0.4
0.6
0.8
1.0
1.2
MG30-KNO3
MG30-Cs2
CO3
MG30-K2
CO3
CO2
sorptioncapacity[mol/kg]
MG30
Figure 7 Comparison of the sorption capacity of CO2 for pure and
alkali-modified HTlc at 676 K, pCO2 of 0.40 bar. *
*Oliveira et al., Sep. Purif. Technol., 2008, 62, 137–147.
Wu et al., Chem. Eng. Technol., 2013, 36(4), 567-574.
**Meis et al., Ind. Eng. Chem. Res., 2010, 49, 8086–8093.

18. 4. Material Development
K-Cu-Ni-HTlc (20-5-5 wt. %) hybrid material preparation
– Impregnation
• MG30 HTlc+ Ni(NO3)2 + Cu(NO3)2 + KNO3, Ultrasonic 6h, 483 K 24h
– Calcination
• Ni(NO3)2 + Cu(NO3)2 + 2KNO3 → NiO + CuO + K2O + 6NO2 + 3/2O2, 723 K 48h
– Reduction
• NiO + CuO + 2H2 → 2Ni0.5Cu0.5 + 2H2O, 723 K ~3h
17
40 42 44 46 48
Cu-HTlc
K-HTlcCu Ni
K-Cu-Ni-HTlc
Ni-HTlc
2 [o
]
Cu-Ni
a)
Figure 8 Comparison of XRD patterns (a) and the SEM graph of the K-Cu-Ni-HTlc material (b).
Cunha et al., Ind. Eng. Chem. Res., 2014, 53 (10), 3842–3853.

19. 4. Material Development
K-Cu-Ni-HTlc hybrid material for tests
– Adsorption and SE-SRE reaction performance
18
Cunha et al., Ind. Eng. Chem. Res., 2014, 53 (10), 3842–3853.
0 10 20 30 40 50
0.0
0.2
0.4
0.6
0.8
1.0
T = 669 K
T = 721 K
T = 763 K
qCO2
[mol/kg]
pCO2
[kPa]
a)
0 500 1000 1500 2000 2500 3000
0
20
40
60
80
100
T = 773 K
mcat
/nEtOH,0
= 43.7 gcat
.hmol-1
t [s]
yCH4
yH2
yCO2
b)
.
yH2
,CO2
,CH4
[mol%]
0
4
8
12
16
20
yCO
yCO
[mol%]
Figure 9 CO2 adsorption isotherms (a) and SE-SRE reaction (b) over K-Ni-Cu-HTlc material at
773 K, 101 kPa, RS/E = 10.
Cu-particles
H2C2H5OH,
H2O
K-Promoted HTlcNi-particles
H2 Yield CO2 Yield

20. 5. Process Study
SE-SRE operation in a single column
– Column arrangement
– Reaction conditions
19
0 2 4 6 8 10
0
1500
3000
4500
6000
7500
time[s]
RS/C
[mol/mol]
CO content limit (< 30 ppm)
H2
purity limit (> 99%)
Allowable operation region
a)
0 2 4 6 8 10
0.0
0.3
0.6
0.9
1.2
1.5
H2
produced[mol/kg]
RS/C
[mol/mol]
b)
0.0
0.2
0.4
0.6
0.8
1.0
H2
productivity
Thermal efficiency
Thermalefficiency[kJ/kJ]
Figure 10 The effect of RS/C conditions on operation window (a) and hydrogen production
performance (b) with u0 = 0.1 m∙s-1, p = 101.3 kPa at 773 K.
Wu et al., Ind. Eng. Chem. Res., 2014, 53 (20), 8515–8527.

21. q'L pL
qH
pH
qL
PSA+TSA
TSA
H = high
L = low
TH
TL
PSA
.
..
.
5. Process Study
Pressure effect
– Volume increase reaction
– Enhance sorbent performance
Periodically regeneration
– Pressure swing (PSA)
– Thermal swing (TSA)
– Inert purge (concentration swing)
20
Figure 12 Methods for sorbent regeneration.
p
[kPa]
Operation time
[s]
H2 produced
[mol∙kg-1]
Thermal efficiency
[kJ/kJ]
101.3 2410 0.761 0.799
304.0 930 0.853 0.791
506.6 485 0.717 0.778
Table 3 Operating performance in SE-SRE under different pressure
conditions with CO content (< 30 ppm) limit.
0 1 2 3 4 5 6
0.0
0.2
0.4
0.6
0.8
1.0 Adsorbed
101.3 kPa
202.7 kPa
304.0 kPa
405.3 kPa
506.6 kPa
qCO2
[mol/kg]
z [m]
Equilibrium
Figure 11 SE-SRE performance under different
pressure conditions.

22. 5. Process Study
Operating scheme for continuous H2 production
SE-SRE vs. SRE performance
21
Operation
H2 yield
[mol %]
CO2 yield
[mol %]
Thermal
efficiency
[kJ∙kJ-1]
H2
productivity
[mol∙kg-1h-1]
SE-SRE 78.5 75.0 0.45 0.51
SRE 38.3 51.0 0.47 0.93
Table 4 Comparison of hydrogen production performance for SRE
process and cyclic SE-SRE process under CSS.
EtOH
H2O
H2
CO2
H2O
H2O
H2O
H2
Reaction
Rinse Regeneration
Purge
CO2(gas)CO2(ads)
H2(gas)
CO2(ads)CO2(gas)
CH4, H2
COX, H2O
H2O
CO2(gas)CO2(ads)
tinitial treaction trinse tregeneration tpurge
Pressure
pH
pL
Time
H2O, H2
Wu et al., Ind. Eng. Chem. Res., 2014, 53 (20), 8515–8527.

23. 5. Process Study
Two-dimensional adsorptive reactor
– Model validation (dR = 3.3 cm)
22
Figure 13 Product distributions as a function of time. Operating conditions: T = 773 K, p = 101 kPa
and RS/E = 10. nEtOH,0 = 4∙10-5 mol∙s-1 (a) and 8∙10-5 mol∙s-1 (b).
0 500 1000 1500 2000 2500 3000 3500
0
20
40
60
80
100
yH2
yCO2
t [s]
yCH4
a)
yH2
,CO2
,CH4
[mol%]
0
10
20
30
40
50
PostbreakthroughBreakthrough
yCO
yCO
[mol%]
Pre-
Breakthrough
0 500 1000 1500 2000 2500 3000 3500
0
20
40
60
80
100
yCH4
yH2
yCO2
PostbreakthroughBreakthrough
Prebreakthrough
yH2
,CO2
,CH4
[mol%]
t [s]
b)
0
10
20
30
40
50
yCO
yCO
[mol%]
,
1
t t
Radial Axial
i i i
r r z zi i
ConvectiveConvective
Diffusive Diffusive fluxflux
flux flux
i r
C r C
C y y
D u C r D u C
t r r r z z
r
   
   
   
   
   
   
   
   
      
    
 ,eaction i adsorptionr
Wu et al., Chem. Eng. Sci.., 2014, DOI: 10.1016/j.ces.2014.07.005.

24. 5. Process Study
Reactor dynamics (dR = 10 cm)
23
Figure 14 The temperature profiles of the pellet (a,b) and CO2 reaction/adsorption rate (c,d)
during the SE-SRE reaction at 773 K, 304 kPa, RS/C = 4 and n0= 0.05 mol∙s-1.
0 1 2 3 4 5 6
-0.04
-0.02
0.00
0.02
0.04
z [m]
r[m]
763.0
764.0
765.0
766.0
767.0
768.0
769.0
771.0
772.0
773.0
Tp
[K]a)
t = 1200 s
0 1 2 3 4 5 6
-0.04
-0.02
0.00
0.02
0.04
z [m]
r[m]
763.0
764.0
765.0
766.0
767.0
768.0
769.0
771.0
772.0
773.0
Tp
[K]b)
t = 2400 s
0 1 2 3 4 5 6
0
1
2
3
4
CO2
Forming CO2
Adsorbing
at r = 0 m
at r = 0.05 m
rCO2
[mol/(m3
pellet
s)]
z [m]
c)
at t = 1200 s
0 1 2 3 4 5 6
0
1
2
3
4
CO2
Forming CO2
Adsorbing
at r = 0 m
at r = 0.05 m
rCO2
[mol/(m3
pellet
s)]
z [m]
d)
at t = 2400 s

25. 5. Process Study
Continuous hydrogen production process
24
Figure 15 Four-column schemes and cyclic configurations
employed SE-SRE process.
Figure 16 SE-SRE performance (a) and the CO2
loading profile at the end of reaction
step (b) during cyclic operation.
0 10 20 30 40 50
99.0
99.2
99.4
99.6
99.8
100.0
H2
purity [mol %]
Cycle number
H2
purity[mol%]
0
5
10
15
20
25
30
CO content [ppm]
COcontent[ppm]
a)
0 1 2 3 4 5 6
0.0
0.2
0.4
0.6
0.8
Cycle 1
Cycle 2
Cycle 3
CSS
qCO2
[mol/kg]
z [m]
b)
r = 0 m
fresh sorbent
Wu et al., Chem. Eng. Sci.., 2014, DOI: 10.1016/j.ces.2014.07.005.

26. 6. Conclusions
High purity H2 can be obtained from SE-SRE with HTlc
material as CO2 sorbent
Hybrid material can be prepared from the impregnation of
active phase(s) on the HTlc material as sorbent
KNO3 is found to be a good alkali promoter
Continuous high purity H2 production can be performed
with a four-column pressure swing operating scheme
Radial temperature gradient should be considered in a
large reactor for SE-SRE
25

27. 7. Future Work
Material developments
– Adsorption performance improvement
– Pellet preparation and test
– Mechanical strength
Process developments
– Kinetic model with carbon deposit
– Real-gas thermodynamic model
– Sorption enhanced oxidative and auto-thermal reforming
– Integration with fuel cell model
SERP concept for H2 production from other feedstocks
– Biogas, glycerol, syngas, biomass…
26

28. Acknowledgement
27
Supervisor: Prof. Alírio E. Rodrigues, University of Porto
Co-advisor: Dr. Adelino F. Cunha, University of Porto
Prof. Jian-Guo Yu and Prof. Ping Li, East China University
of Science and Technology
Helps from LSRE/LCM group and DEQ-FEUP.
Doctoral grant from China Scholarship Council
– CSC 2010674011

29. Thank you for your attention!
Questions?
28