1. IMDEA Energy
4.4.2011
Liquid Fuels
from
Water, CO2, and Solar Energy
Aldo Steinfeld

2. Sunlight + H2O + CO2 = Fuels
Syngas
(H2 , CO)
H2O, CO2
Liquid Fuels
• Diesel
• Jet Fuel
• Methanol

3. 20 MW-electric/ 100 MW-thermal
11 MW-electric / 55 MW-thermal
(Sevilla, Spain)

4. H2O  H2 + ½ O2
300
250 H°
200
G°
[kJ/mol]
150
100
TS°
50 Equilibrium Mole Fraction
p = 1 bar
0 1
H2O
0.9 H
-50
1000 2000 3000 4000 5000 0.8 O
H2
0.7
Temperature [K] OH
0.6 O2
0.5
0.4
0.3
0.2
0.1
0
2000 2500 3000 3500 4000
Temperature [K]

5. Solar Thermochemical Splitting of H2O and CO2
Concentrated
Solar Energy
MOox 1st step: Solar Reduction O2
MOox  MOred  O2 MOred
2nd step: Oxidation
H2/CO
H2O/CO2 MOred  H 2O  MOox  H 2
MOred  CO2  MOox  CO
To
recycle
MOox Liquid Fuels

6. Solar Thermochemical Splitting of H2O and CO2
Concentrated
Solar Energy
MOox 1st step: Solar Reduction O2
ZnO  Zn  0.5O2 Zn
2nd step: Oxidation
H2/CO
H2O/CO2 Zn  H 2O  ZnO  H 2
Zn  CO2  ZnO  CO
To
recycle
MOox Liquid Fuels

7. Qsolar T = 2000K
Concentrated
Solar
Radiation
I = 1 kW/m2 Qrerad
C = 5000 ZnO Zn + ½ O2
@ 298 K @ 2000 K
WF.C. 35% no h.r.
 
Qsolar  58% with h.r.
WF.C.
Qquench Quench
QF.C.
½ O2 Zn
Ideal H2O
Fuel
Cell
Hydrolyser
Qhyd
H2 ZnO

8. Solar Thermochemical Splitting of H2O and CO2
Concentrated
Solar Energy
MOox 1st step: Solar Reduction O2
ZnO  Zn  0.5O2 Zn
2nd step: Oxidation
H2/CO
H2O/CO2 Zn  H 2O  ZnO  H 2
Zn  CO2  ZnO  CO
To
recycle
MOox Liquid Fuels

9. ZnO/Zn Cycle
water/gas
rotary inlets/outlets
ZnO feeder
joint
cavity-receiver
ZnO
Zn+½ O2
quartz
window
Concentrated
Solar
Radiation
• Chem. Eng. J. 150, 502-508, 2009.
• Materials 3, 4922-4938, 2010.

10. ZnO/Zn Cycle
water/gas
rotary inlets/outlets
ZnO feeder
joint
cavity-receiver
ZnO
Zn+½ O2
quartz
window
2400 100
Concentrated 2200 90
ZnO-Temperature [K]
Solar
2000 80
Radiation
1800 70
Shutter [%]
1600 60
• Treactor = 2000 K
1400 50
• Qsolar = 10 kW
1200 40
• Cpeak = 5880 suns 1000 30
• mZnO = 11 g/min 800
Temperature
Temperatu [K]
20
• Zn yield = 50 – 95 % 600 Shutter
Shutte [%] 10
0
0 100 200 300 400 500 600 700
• Chem. Eng. J. 150, 502-508, 2009. Time [sec]
• Materials 3, 4922-4938, 2010.

11. Solar Reactor Technology
10 kW 100 kW
• Heat transfer + kinetic model validated
E
T  A
cp   keff T   k0 e RT  H r T 
t  
     9 feed cycles; 131g each
heat chemistry
transfer
ZnO dissociated (g)
# feed-cycles Measured Calculated
3 68.5 ± 5.2 63.9
5 59.5 ± 6.8 54.0
7 148.4 ± 28.8 223.3
• AIChE J. 55, 1497-1504, 2009. 9 224.2 ± 49.5 197.1
• Chem. Eng. J. 150, 502-508, 2009.
• Int. J. Heat Mass Transfer 52, 2444-2452, 2009.

12. Solar Reactor Technology
100 kW
Solar radiative input 100 kW 10 kW
Cavity diameter 580 160 mm
Cavity length 750 230 mm
Outlet diameter 110 15 mm
Al2O3-tile thickness 10 7 mm
Outer shell diameter 1080 200 mm
Aperture diameter 190 60 mm
Window diameter 485 160 mm
Solar concentration ratio 3500 3500 suns

13. Solar Thermochemical Splitting of H2O and CO2
Concentrated
Solar Energy
MOox 1st step: Solar Reduction O2
ZnO  Zn  0.5O2 Zn
2nd step: Oxidation
H2/CO
H2O/CO2 Zn  H 2O  ZnO  H 2
Zn  CO2  ZnO  CO
To
recycle
MOox Liquid Fuels

14. 2nd step: Syngas Production
Aerosol reactor concept
Experimental nanoparticle
mixing in-situ hydrolysis
Set-up H2O(g) formation H2O H2 H2
ZnO
gas analysis
filter Zn(g) Zn
ZnO
steam
generator Quench rate: up to 106 K/s
reaction 1200 H2O/Ar
zone injection
Zn
Temperature [K]
H2O + Zn  Ar H2O crucible
ZnO + H2 1000
T = 573-1263K
Tsat
800
evaporation
zone 600
evaporation reaction zone
Zn  Zn(g)
400
T = 1263 K 0 20 40 60 80 100
Distance along reactor axis [cm]
Balance Ar
• Chem. Eng. Sc. 64, 1095-1101, 2009.
• Chem. Eng. Sc. 65, 1855-1864, 2010.

15. 2nd step: Syngas Production
Aerosol reactor concept
Experimental nanoparticle
mixing in-situ hydrolysis
Set-up H2O(g) formation H2O H2 H2
ZnO
gas analysis
filter Zn(g) Zn
ZnO
steam 9
generator TR = 973 K
reaction 8 Zn evaporation
zone
7
H2O + Zn  Ar H2O 6
ZnO + H2
10-4 mol/min
H2 production
T = 573-1263K 5
4
3
evaporation
zone 2
= Zn-conversion = 90%
1
Zn  Zn(g)
0
T = 1263 K
0 10 20 30 40 50 60 70
Reaction time (min)
Balance Ar
• Chem. Eng. Sc. 64, 1095-1101, 2009.
• Chem. Eng. Sc. 65, 1855-1864, 2010.

16. 2nd step: Syngas Production
Aerosol reactor concept
Experimental nanoparticle
mixing in-situ hydrolysis
Set-up H2O(g) formation H2O H2 H2
ZnO
gas analysis
filter Zn(g) Zn
ZnO
steam TR = 823 K
generator
reaction
zone
H2O + Zn  Ar H2O
ZnO + H2
T = 573-1263K
evaporation
zone
Zn  Zn(g)
T = 1263 K
Balance Ar
• Chem. Eng. Sc. 64, 1095-1101, 2009.
• Chem. Eng. Sc. 65, 1855-1864, 2010.

17. Solar Thermochemical Splitting of H2O and CO2
Concentrated
Solar Energy
MOox 1st step: Solar Reduction O2
MOox  MOred  O2 MOred
2nd step: Oxidation
H2/CO
H2O/CO2 MOred  H 2O  MOox  H 2
MOred  CO2  MOox  CO
To
recycle
MOox Liquid Fuels

18. DLR, Germany SNL, USA Concentrated solar flux
ZnFe2O4 CoFe2O4
N2 + O2 Window
H2
O2 O2
N2
H2O
Niigata U., Japan CO2 (or steam) CO2 (or steam)
NiFe2O4
Gas exhaust CO and CO2 (or H2 and H2O)
U. of Colorado, USA
Cyclone NiFe2O4 CNRS, France
ZnO, SnO2
Draft tube
Internal circulating
fluidized bed
(NiFe2O4/m-ZrO2 ) Conical-
shaped cap
Nitrogen / Steam flow

19. Solar Thermochemical Splitting of H2O and CO2
Concentrated
Solar Energy
MOox 1st step: Solar Reduction O2

CeO2  CeO2  O2 MOred
2
2nd step: Oxidation
H2/CO
H2O/CO2 CeO2   H 2O  CeO2   H 2
CeO2   CO2  CeO2   CO
To
recycle
MOox Liquid Fuels

20. Solar Reactor Technology
Science 330, 1797-1801, 2010.

21. Solar Experimental Set-up
Science 330, 1797-1801, 2010.

22. Solar Experimental Results
CO2-splitting H2O-splitting
solar-to-fuel 
heating value of fuel produced 0.8%

for CO2 -splitting
solar energy input  + energy for inert gas recycling  0.7% for H2O-splitting
Science 330, 1797-1801, 2010.

23. Solar Experimental Results
Simultaneous splitting of CO2 & H2O
• H2O/CO2 = 7 → H2/CO = 1.91
• Fuel/O2 = 2

24. Solar Experimental Results
Simultaneous splitting of CO2 & H2O
0.6 2.65 ml H 2 g -1 2.45 ml H 2 g -1 2.43 ml H 2 g -1 2.29 ml H 2 g -1 2.00 ml H 2 g -1 2.17 ml H 2 g -1 2.10 ml H 2 g -1 2.19 ml H 2 g -1 1.76 ml H 2 g -1 1.92 ml H 2 g -1
Rate [mL min‐1 g‐1]
1.22 ml CO g -1 1.06 ml CO g -1 1.03 ml CO g -1 0.99 ml CO g -1 2.00 ml CO g -1 0.90 ml CO g -1 0.91 ml CO g -1 0.83 ml CO g -1 0.76 ml CO g -1 0.74 ml CO g -1
0.5 H2/CO ratio: 2.17 H2/CO ratio: 2.31 H2/CO ratio: 2.36 H2/CO ratio: 2.32 H2/CO ratio: 2.01 H2/CO ratio: 2.43 H2/CO ratio: 2.28 H2/CO ratio: 2.63 H2/CO ratio: 2.31 H2/CO ratio: 2.59
0.4
0.3
2.14 ml O 2 1.73 ml O 2 1.69 ml O 2 1.46 ml O 2 1.56 ml O 2 1.48 ml O 2 1.34 ml O 2 1.28 ml O 2 1.23 ml O 2 1.23 ml O 2
0.2 g-1 CeO 2 g-1 CeO 2 g-1 CeO 2 g-1 CeO 2 g-1 CeO 2 g-1 CeO 2 g-1 CeO 2 g-1 CeO 2 g-1 CeO 2 g-1 CeO 2
0.1
0
0 50 100 150 200 250 300 350 400 450
Temperature [K]
1900
1700
1500
1300
1100
900
700
0 50 100 150 200 250 300 350 400 450
Time [min]

25. RPC
I
s
• average pore diameter = 2.54 mm
• total porosity = 92%
• specific surface = 11 mm-1
Reticulate Porous Ceramic
30 mm
35
mm
4 3 mm
• ASME Journal of Heat Transfer 132, 023305 1-9, 2010.

26. Radiative properties of RPC
dI   s 4
    I      Ib   I  d i
ds 4  0 
I   
  
   i

Change of attenuation augmentation augmentation
radiation by by by
intensity absorption+scattering internal emission incoming scattering
s
MC ray tracing
I s
 exp  -  s 
I0
  0.22 cm-1
• ASME Journal of Heat Transfer 132, 023305 1-9, 2010.

27. Fluid transport properties across RPC
• Navier-Stokes by DNS
• 0.2<Re<200
• 0.1<Pr<10

p   uD  F  uD
2
K
pd 2
 c0  c1 Re
 uD
K  1.353 10-7 m 2
F  444.02 m 1
• Int. J. Heat and Fluid Flow 29, 315–326, 2008

28. Heat transfer transport across RPC
• Navier-Stokes by DNS
• 0.2<Re<200
• 0.1<Pr<10
z z
 q ''dAsf
hsf  z
Tlm  Asf
Nu  1.56  0.6 Re0.56 Pr 0.47
• J. Heat Transfer 130, 032602, 2008.
• J. Heat Transfer, 132, 023305 1-9, 2010

29. CO2 Capture from Air
calcination/carbonation CaO + CO2 CaCO3
nCO2 ,released
CO2-depleted air / CO2  99%
nCO2 ,captured
12000 900
T=390 °C / 850°C
850°C
Calcination
Calcination
Calcination
Calcination
Calcination
800
Temperature [°C]
10000
700
Carbonation
Carbonation
Carbonation
Carbonation
Carbonation
8000 600
CO2 [ppm]
500
atmospheric air 6000
400
390°C
4000 300
200
2000
100
input 390 ppm
0
0 1000 2000 3000 4000 5000 6000
Time [sec]
Chem. Eng. J. 146, 244–248, 2009.

30. • Diamine-functionalized silica gel
• CO2 adsorption from air at 25 °C and 1 bar
• Pure CO2 desorption at 74-90 °C and 10-150 mbar

31. Solar Energy Concentrated
Solar Energy
adsorption reduction
atmospheric
CO2 catalytic
air syngas
conversion
desorption oxidation
H2O
CO2-depleted liquid fuels
air for transportation
H2O
CO2

32. Jan Wurzbacher Tina Daum
Chris Gebald Christian Wieckert
Roman Bader Ivo Alxneit
Giw Zanganeh Daniel Mayer
Clemens Suter Alwin Frei
Men Wirz Yvonne Bauerle
Anastasia Stamatiou Christian Hutter
Emilie Zermatten Peter Schaller
Jonathan Scheffe Tony Meier
Philipp Furler Marc Chambon
Gilles Maag Daniel Wuillemin
Michael Kruesi
Illias Hischier
Willy Villasmil
Philipp Haueter
Matt Roesle
Tom Cooper
Peter Loutzenhiser
Dominic Herrmann
Enrico Guglielmini
Nic Piatkowski