Development of CVD Silica Membranes Having High Hydrogen Permeance and Steam Durability and a Membrane Reactor for a Water Gas Shift Reaction

Water gas shift reaction of carbon monoxide (CO) with membrane reactors should be a promising method for hydrogen mass-production because of its high CO conversion, high hydrogen purity and low carbon dioxide emission. For developing such membrane reactors, we need hydrogen permselective membranes with high hydrogen permeance with order of 10−6 mol m−2 s−1 Pa−1 at 573 K and high steam durability. In this study, we have optimized the kind of substrates, precursors, vapor concentration, and chemical vapor deposition (CVD) time using the counter-diffusion CVD method for developing such membranes. The developed membrane prepared from hexamethyldisiloxane has a hydrogen permeance of 1.29 × 10−6 mol m−2 s−1 Pa−1 at 573 K and high steam durability. We also conducted water gas shift reactions with membrane reactors installed the developed silica membranes. The results indicated that reactions proceed efficiently with the conversion around 95–97%, hydrogen purity around 94%, and hydrogen recovery around 60% at space velocity (SV) 7000.

High-performance carbon molecular sieve membranes for hydrogen purification and pervaporation dehydration of organic solvents

Successful synthesis of a ceramic-supported ultrathin carbon membrane with unprecedently high hydrogen permeance and outstanding H2/CO2, H2/N2 and H2/CH4 selectivities at elevated temperatures.

Synthesis of a zeolite membrane as a protective layer on a metallic Pd composite membrane for hydrogen purification

A zeolite membrane was synthesized on the surface of Pd membrane by seed-free hydrothermal synthesis. The zeolite membrane, which was used as an “armor”, offered good protection to the Pd membranes, significantly suppressing hydrogen permeance loss.

Experimental Study of Hydrogen and Methane Permeation through Asymmetric PEI Membranes

Reducing the amount of off-gases to flare is an important issue addressed by petrochemical plants and refineries. Therefore, separation of hydrogen from methane is crucial monetary and environmental incentives for these industries. The current research is aimed preparation of asymmetric polyetherimide(PEI) membranes for this purpose. The different mechanism of gas intake in PEI resulted in a decrease in hydrogen permeance and selectivity and adverse behavior for methane with pressure enhancement. There was a decline in both gases permeance and unexpected enhancement in selectivity. The effect of bath temperature was demonstrated. An effective coating method was applied and the selectivity increased noticeably.