Membrane Development for the Separation of H2 and CO2: Pd/Ag Alloy Membranes

As a fall-back response to the possibility of Global Warming due to increasing concentrations of greenhouse gases in the atmosphere, British Coal is investigating Low-CO₂ Power Generation options. One of the most promising options is an Integrated Gasification Combined Cycle (IGCC) system using a membrane separation unit to separate H₂ and CO₂. However, the performance requirements cannot be met by currently available commercial membranes. A small-scale membrane permeation test rig has been designed and built at CRE to aid development of novel membranes.This paper describes tests carried out on Pd/Ag alloy membranes, which are the most promising for the separation of H₂ and CO₂. The tests examined the variation of permeation rate with pressure, temperature, and pressure drop. Results of the tests are reported, with recommendations for further work to improve performance.