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*STTR Project: H₂ Separation Membranes—TDA Research, Inc., 12345 W. 52^nd Avenue, Wheat Ridge, CO 80033-1916; 303-940-2300; www.tda.com

Dr. Gokhan Alptekin, Principal Investigator, galptekin@tda.com

Mr. John D. Wright, Business Official, jdwright@tda.com

DOE Grant No. DE-FG02-06ER86290

Amount: $750,000

Research Institution

Colorado School of Mines

Golden, CO

Recent advances in metal membrane technology have shown that Pd-alloy composite membranes are not susceptible to the embrittlement and poisoning problems that have prevented widespread industrial use of Pd for high temperature H₂ separation from coal-derived synthesis gas. However, there still remains a significant challenge to prepare thin membranes on porous stainless steel (PSS) substrates, in order to provide the robustness and ruggedness required in industrial processes. In particular, there are several issues related to the use of PSS supports: (1) the surface roughness of the steel supports must be reduced to make a defect-free thin Pd alloy film, and (2) a diffusion barrier must be in place to prevent metal migration at the tube-film interface (e.g., diffusion of iron from the steel into the Pd membrane). This project will develop a simple and effective technique to modify the surface of stainless steel supports, thereby enabling the preparation of very thin Pd alloy films. In Phase I, various thin Pd alloy membranes films were developed, the films were prepared on porous stainless steel substrates, and their potential for hydrogen separation was demonstrated. It was shown that membrane performance was not affected by the major constituents of the synthesis gas (CO, CO₂, and H₂O). Moreover, the membranes were tolerant of sulfur poisoning and achieved favorable flux and selectivity. In Phase II, the membranes will be optimized, production will be scaled-up, and their effectiveness in the presence of other synthesis gas contaminants will be demonstrated.

Commercial Applications and Other Benefits as described by the awardee: Pd membranes should find use in separating hydrogen produced in hydrocarbon reforming, the water-gas shift reaction, and coal gasification for power generation in fuel cells. Such applications have the potential to reduce energy consumption and capital costs.