Optimization of Metal Alloys for High Pressure Hydrogen Separation Membranes

75201S One of the technological barriers to developing an efficient and low-cost hydrogen-separation membrane technology is hydrogen-induced embrittlement associated with the hydrogen-permeable metals at high hydrogen pressure and low temperature. This project will develop ruggedized and efficient alloy membranes that can resist fracture under a broad range of temperature and pressure conditions. New membrane materials will be developed by systematically alloying various elements in order to improve the membrane resistance to fracture. Substituents will be introduced into the membrane lattice to manipulate hydrogen solubility, scavenge interstitial impurities, and control alloy grain size. In Phase I, ten different binary and ternary Group VB-based alloys were prepared and fabricated into dense hydrogen transport membranes. The hydrogen permeation through such membranes was systematically studied at high hydrogen pressure differential (up to 12 bar) in a temperature range of 200-440¿C. Important material characteristics that affected membrane performance were identified. Phase II will focus on identifying the optimum membrane composition (which is not only highly hydrogen-permeable but also maintains high mechanical integrity under a broad range of process conditions). A cost effective protocol for fabricating large planar alloy membranes will be developed, and a scaled-up membrane unit will be designed, constructed, and tested. Commercial Applications and Other Benefits as described by the awardee: High-performance, low-cost hydrogen transport membranes should significantly contribute to the commercial implementation of IGCC and FutureGen power plants. Hydrogen separation membranes also should be key components for the low cost supply of hydrogen for Fischer-Tropsch liquid fuels synthesis, fuels hydrodesulfurization, and as a fuel feedstock for fuel cells.