Sulfur Poisoning Resistant Palladium/Gold Alloy Membranes for High Temperature Hydrogen Separation

TDA Research, Inc., in collaboration with Colorado School of Mines (CSM) is developing a water-gas-shift membrane reactor that combines a sulfur tolerant, PdAu alloy composite membrane and a sour shift catalyst. The membrane reactor converts sulfur-containing CO-rich synthesis gas into a pure hydrogen permeate and a high pressure CO2-rich retentate stream.

This paper discusses the potential of using the PdAu membranes in the novel membrane water-gas-shift reactor. PdAu alloys have been shown to resist poisoning by H2S. Our fabrication process allows preparation of a composite membrane with a micron thick palladium alloy layer, providing high flux and acceptable selectivity at the minimum cost. The effect of the water-gas-shift components on the performance of the PdAu membranes was examined at the conditions of interest. In bench-scale tests, poisoning and/or inhibition effects of CO, CO2, H2O and H2S on separation properties were examined at 430 kPa and at 350-450°C temperature range.