ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS
Eltron Research Inc., and team members, are developing an environmentally benign, inexpensive, and efficient method for separating hydrogen from gas mixtures produced during industrial processes, such as coal gasification. This project was motivated by the National Energy Technology Laboratory (NETL) Vision 21 initiative which seeks to economically eliminate environmental concerns associated with the use of fossil fuels. This objective is being pursued using dense membranes based in part on Eltron-patented ceramic materials with a demonstrated ability for proton and electron conduction. The technical goals are being addressed by modifying single-phase and composite membrane composition and microstructure to maximize proton and electron conductivity without loss of material stability. Ultimately, these materials must enable hydrogen separation at practical rates under ambient and high-pressure conditions, without deactivation in the presence of feedstream components such as carbon dioxide, water, and sulfur. During this quarter, ceramic, cermet (ceramic/metal), and thin film membranes were prepared, characterized, and evaluated for H{sub 2} transport. For selected ceramic membrane compositions an optimum range for transition metal doping was identified, and it was determined that highest proton conductivity occurred for two-phase ceramic materials. Furthermore, a relationship between transition metal dopant atomic number and conductivity was observed. Ambipolar conductivities of {approx}6 x 10{sup -3} S/cm were achieved for these materials, and {approx} 1-mm thick membranes generated H{sub 2} transport rates as high as 0.3 mL/min/cm{sup 2}. Cermet membranes during this quarter were found to have a maximum conductivity of 3 x 10{sup -3} S/cm, which occurred at a metal phase contact of 36 vol.%. Homogeneous dense thin films were successfully prepared by tape casting and spin coating; however, there remains an unacceptably high difference in shrinkage rates between the film and support, which led to membrane instability. Further improvements in high pressure membrane seals also were achieved during this quarter, and a maximum pressure of 100 psig was attained. CoorsTek optimized many of the processing variables relevant to manufacturing scale production of ceramic H{sub 2} transport membranes, and SCI used their expertise to deposit a range of catalysts compositions onto ceramic membrane surfaces. Finally, MTI compiled relevant information regarding Vision 21 fossil fuel plant operation parameters, which will be used as a starting point for assessing the economics of incorporating a H{sub 2} separation unit.
- Research Organization:
- Eltron Research Inc. (US)
- Sponsoring Organization:
- (US)
- DOE Contract Number:
- FC26-00NT40762
- OSTI ID:
- 809131
- Resource Relation:
- Other Information: PBD: 30 Jul 2001
- Country of Publication:
- United States
- Language:
- English
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ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS
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