Optimization of Metal Alloys for High Pressure Hydrogen Separation Membranes
DOE Phase II Contract DE-FG02-04ER83935
One of the technological barriers to developing an efficient and low-cost hydrogen separation membrane technology is hydrogen-induced embrittlement associated with hydrogen-permeable metals at high hydrogen pressure and low temperature. This program is directed toward developing ruggedized and efficient alloy membranes that can resist fracture under a broad range of temperature and pressure conditions. The focus of this program is to develop new membrane materials by systematically alloying various elements in order to improve membrane resistance towards fracture. Completion of this Phase II program will make an important step toward refining Eltron’s hydrogen transport membrane technology for a wide range of energy related applications.
Substituents are being introduced into the membrane lattice which manipulate hydrogen solubility, simultaneously scavenge interstitial impurities and control alloy grain size. This strategy is allowing us to develop stable alloys compatible with operating under a wide variety of process conditions.
In Phase I, ten different binary and ternary Group VB-based alloys were prepared and fabricated into dense hydrogen transport membranes. 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. Clear strategies for optimizing membrane hydrogen permeability and ruggedness were identified.
The Phase II program 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. Furthermore, a cost effective protocol of fabricating large planar alloy membranes will be developed, and a scaled-up membrane unit will be designed, constructed and tested.
Commercial implementation of IGCC and FutureGen power plants need high performance, low cost, hydrogen transport membranes. Technology being developed in this program will significantly contribute to this enabling technology. Hydrogen separation membranes will also 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.