A sol-gel method was applied for the development of highly permeable hydrogen separation membranes using bis(triethoxysilyl)ethane (BTESE) as a silica precursor. Hybrid silica membranes showed quite high hydrogen permeance (1 x 10(-5) mol m(-2) s(-1) Pa(-1)) with a high H(2)-to-SF(6) selectivity of 1000 because of loose organic-inorganic silica networks. Hybrid silica membranes were found to show high hydrothermal stability due to the presence of Si-C-C-Si bonds in silica networks.

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The dehydrogenation of methylcyclohexane (MCH) in catalytic membrane reactors for hydrogen production was studied experimentally and theoretically. The membrane reactor was composed of a Pt/γ-Al 2 O 3 /α-Al 2 O 3 catalytic support and a H 2 -selective silica separation layer, showing H 2 permeances of (1.51−2.83) × 10 −6 mol m −2 s −1 Pa −1 with H 2 /SF 6 permeance ratios of 290−1000 at 473 K. The MCH conversion was markedly increased after hydrogen extraction from the membrane reactor, which agreed very well with the results obtained by simulation using a proposed mathematical model. The effects of the catalytic activity and hydrogen extraction rate on membrane reactor performance were investigated during the simulations. A system combining a fixed-bed prereactor and a membrane reactor was proposed for MCH dehydrogenation, which further improved the MCH conversion as a result of the enhanced driving force for hydrogen extraction from the membrane reactor.

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