Low-cost oxygen membranes

Low-cost oxygen membranes
A. Kaiser
RISØ National Laboratory for sustainable Energy
Danish Technical University - DTU
Christodoulos Chatzichristodoulou
Julie Glasscock
Søren Foghmoes
Peter Vang Hendriksen
Mogens Bjerg Mogensen
Nikolaos Bonanos
Séverine Ramousse
Robert K. Feidenhans’l
Low Cost Oxygen Membranes
Agenda:
• Applications for oxygen membranes
• Objectives of project
• Membrane material development (WP1)
• Manufacturing and characterization (WP2+WP3)
• Future challenges
Oxygen Transport Membranes: Possible applications
• Syngas production
• Gasification of biomass
• Power Plant with sequestration of CO2
•
•
coal gasification
oxyfuel (high pO2)
Larger Programs:
• FutureGen: 1 Billion dollars, 10 years
• MemBrain, Helmholtz-Allianz (FZJ,…)
Oxygen transport membranes for gas separation
Principle:
Syngas
CO + 2H 2
Methane gas
CH 4
MIEC
δ
O2
σO
2-
O2kO
eσe-
Air
Advantages:
- Selectivity (100 %)
- Oxidation and separation combined in one unit
- Environmentally friendly
Objectives of Low Cost Oxygen Membrane Project
Demonstration of ”low cost”, metal-supported oxygen membrane
• Identify mixed conducting membrane materials
• Evaluation of manufacturing routes for membranes
• Oxygen fluxes of 10 ml cm-2 min-1 (on thin film membranes)
Further ”supporting” internal funded projects
• Proof of concept project, ”HP-ITM” (DTU)
• Internal department funding
Material selection for oxygen separation membranes
a) Fluorites (AO2) (Ce0.9Gd0.1O1.95)
b) Perovskites (ABO3) (La0.6Sr0.4FeO3-δ)
c) Ruddlesden-Popper type oxides (A2BO4) (LaSrFe0.5Co0.5O4+δ)
Ceria on metalsupport
• Low Cost
• Good performance
• Stable
B. Dalslet et. al, J. Solid State Electrochem. (2006)
Conductivities of Pr,Tb-co-doped Ceria
Designs for membrane material implementation
Anode supported
CGO membrane
CGO supported
membrane
Metal supported
CGO membrane
CGO
CGO
AAL
Anode support
Porous CGO
CGO
Metal support
Porous CGO
Platform for fast testing
All ceramic design
”Killer piece”
ƒ prepilot production in house
ƒ sintering in air/easy fabr.
ƒ high robustness
ƒ low pO2 operation required
(on Ni/YSZ-support)
ƒ no expansion mismatch
ƒ low cost
ƒ co-sintering difficult
Protection
layer
Facilities for SOFC and membrane fabrication
Lamination
Tape-casting
Combustion Synthesis
Sintering
Spray painting
Screen printing
Anode supported CGO Membrane by Screen Printing
• Size up-scaled to 100 cm2
after printing
after sintering
Cosintering of Metal supported Membrane
EDS of Interface FeCr-alloy and CGO
- after co-sintering below 1200°C in H2/Ar
Results:
- Si enrichment in CGO layer
- Cr at interface to FeCr -alloy
Oxygen flux measurments with modified SOFC facilities
flow of protective inert gas
fuel
out
gold+glass
seals
A
fuel
Membrane
cell
alumina
tube
V
air
air out
in
Figure 2 a) Schematic of 3-atmosphere rig
2b) Photograph of mounted sample in the test rig
Air in
Pt
Pt-mesh
Air flow
weight
Fuel in (pO2)
SOFC
Fuel flow
Ni-mesh
Fuel out (pO2)
Air out
Glass seal
Ni
Active area = 16 cm2, Cross-flow geometry
Cell house, alumina
Furnace
N2-Leak tester
• room temperature device
• small N2-leakages detectable
N2
Air
N2
N2/
Air
Rotameters
Air
Sweep gas
Leak tester
N2/ Air
N2
Purge stream
PO2
Next steps
Materials
• Reduce or control chemical expansion of cerates
• Continue work on perowskites and mixed phase membranes
Co-sintering/manufacturing
• Avoid reaction of doped ceria with metal support
• Adjust shrinkage profiles of layers
Membrane Testing
• Intensify efforts on flux measurments (target: 10 ml cm-2 min-1)
Thank you for your attention!
Prepilot Production of Anode supported Membranes
1. Slurry preparation
2. Tape Casting of AS
8. Catalyst
Impregnation
7. Sintering
5. Co-sintering
Support
3. ”Anode” Spraying
4. Lamination or
screen printing
of CGO membrane
6. ”Cathode” printing
Future challenges