HYDROGEN SEPARATION COMPOSITE MEMBRANE MODULE AND THE METHOD OF PRODUCTION THEREOF

• Main Authors: LI ANWU, GRACE JOHN ROSS, LIM CHOON JIM
• Format: Patent
• Language: English
• Published: 12.11.2009
• Subjects: APPLYING LIQUIDS OR OTHER FLUENT MATERIALS TO SURFACES, IN GENERAL; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; PROCESSES FOR APPLYING LIQUIDS OR OTHER FLUENT MATERIALS TOSURFACES, IN GENERAL; SEPARATION; SPRAYING OR ATOMISING IN GENERAL; TRANSPORTING

This invention relates to a metallic composite membrane for separating hydrogen from a mixed gas, a membrane module and a manufacturing method thereof. The composite membrane consists of a three-layer sandwich structure, e.g. the porous metal substrate, an intermediate layer and the hydrogen-selective dense thin metal layer. In the embodiments of the invention, the porous metal substrates were first pretreated to reduce their surface roughness without reducing their gas permeability. The pretreated substrates were coated with intermediate layer, wherein the intermediate layer served as not only a barrier layer to prevent interdiffusion between the substrate and the hydrogen-selective layer, but also a surface modifier to reduce surface roughness and pore size of the substrate. A hydrogen-selective metal layer was then deposited on the intermediate layer-coated substrate by coating methods. Since the substrate with the intermediate layer has a smoother surface with a smaller pore size, a thinner hydrogen-selective metal membrane can be used to form a dense pinhole-free membrane. This not only reduces the metal loading of the composite membrane, but also increases its hydrogen permeance and selectivity of the composite membrane. The module design according to the invention provides solutions to the problems that result from high welding temperatures or high mechanical compressing force caused by the joining of a composite membrane with other parts through Swagelok, welding, brazing and gasket etc.