Hydrogen & Clean Fuels - Abstract
The Influence of Copper Concentration on the Permeability of Pd-Cu Alloy Membranes
Hydrogen membranes have been identified as a promising technology for extracting pure hydrogen from processes such as coal gasification, hydrocarbon steam-reforming or any hydrogen producing process. Novel palladium-copper (Pd-Cu) alloys continue to be of interest due their highly catalytic surface, high performance, suppression of the hydride-phase transition, tolerance to sulfur compounds, and decreased costs. In this study, the influence of copper concentration on the performance of the Pd-Cu alloy was measured as a function of temperature (350 to 900oC) and pressure (0.1 to 4 MPa) both in the presence of neat hydrogen and a 1000 ppm H2S-H2 mixture. Permeability results indicated that the crystalline phase of the Pd-Cu alloy has significant impact on permeability in the presence of neat hydrogen, with the body-centered-cubic (bcc) structure yielding higher performance results than the face-centered-cubic (fcc) structure. Furthermore, studies conducted in the presence of hydrogen-sulfide yielded “resistance” to poisoning at temperatures corresponding to the fcc crystal structure.