Rh/γ-Al2O3 catalytic layer integrated with sol-gel synthesized microporous silica membrane for compact membrane reactor applications

An efficient and compact catalytic membrane reactor for reforming of CH4 was developed by integrating a hydrogen perm-selective silica membrane with an Rh/gamma-Al2O3 catalyst layer. The catalytic layer was sandwiched between the outer surface of the alpha-Al2O3 support tube and the silica membrane with an aim of improving the heat and mass transfer rates through the system and to simplify the reactor geometry. The system showed improved efficiency for reforming of CH4 at comparatively lower operating temperatures and steam to C molar ratios than the conventional fixed-bed steam reforming systems. Under optimized conditions, a nearly 25-30% improvement from the equilibrium conversion level was achieved as a result of abstraction of hydrogen from the product stream by the silica membrane integrated with the catalyst layer. The performance of the system was evaluated as a function of various process parameters. Because of the compactness and efficiency, the present system emerges as a promising alternative to the conventional membrane reactors, which possess separate catalytic and membrane units.