Hydrogen Produced from Simulated Biogas Using a Membrane Reactor with a Dimethoxydimethylsilane-Derived Silica Membrane Operated under Pressure and without Sweep Gas

We developed a membrane reactor integrating dimethoxydimethylsilane (DMDMS)-derived hydrogen-selective silica membranes with Rh/Al2O3 catalysts and produced high-purity hydrogen from simulated biogas by operating the reac-tor under pressure on the reaction side while maintaining ambient pressure and excluding sweep gas that has often been used on the permeate side. We investigated changes in the performance of the DMDMS-derived membrane when exposed to pressurized hydrothermal conditions. The results indicated that pressure had a nonnegligible effect on mem-brane performance and led to a more severe decline in hydrogen permeance compared with exposure under similar hy-drothermal conditions but at 0.1 MPa pressure. Although the performance of the DMDMS-derived membrane decreased, we developed a membrane reactor and operated it for hydrogen production. For the various pressures (0.6-1.0 MPa) and temperatures (500-600?) tested, the conversions exceeded those in the packed-bed reactor, and high hydrogen purity was achieved without the use of sweep gas. Specifically, 55% conversion with 94% hydrogen purity was achieved when the membrane reactor was operated at 0.6 MPa and 600 & DEG;C.