(44e) Composite Pd-Based Membranes & Membrane Reactors for High Temperature H2 Generation with CO2 Capture

High temperature, inorganic membrane technology is being investigated to perform many of the separations needed for hydrogen generation from fossil fuels or biomass gasification while simultaneously concentrating and capturing CO₂. This talk will focus on high temperature, hydrogen permeable membrane materials, such as palladium or palladium alloys and their integration in catalytic membrane reactors.

Palladium and its alloys, as well as nickel, platinum and the metals in Groups III -V of the periodic table are all permeable to hydrogen. Hydrogen-permeable metal membranes made of palladium and its alloys are the most widely studied due to their high hydrogen permeability, their chemical compatibility with many hydrocarbons containing gas streams, and their theoretically infinite hydrogen selectivity. Our approach has been to fabricate composite membranes consisting of thin, micron-thickness, palladium alloy films on tubular, porous ceramic substrates using proprietary deposition techniques. Trade-offs associated with several Pd alloy composition, permeation data with pure and mixed feed gases at high pressures and temperatures will be presented. Examples of current and developmental process applications of Pd alloy membranes will also be discussed where hydrogen production can be coupled with CO₂ capture. These applications include hydrogen recovery from gasification-derived synthesis gas containing H₂S and a membrane-assisted reactor to produce hydrogen via steam reforming of methane while simultaneously concentrating the CO₂ product.