Patent ID: 6923846

Claim:
A method for separating a fluid mixture into a fraction enriched in a first component and a fraction depleted in the first component, comprising the step of contacting a fluid mixture selected from the group consisting of natural gas-containing mixture, a hydrogen gas-containing mixture and a hydrocarbon gas-containing mixture with a composite membrane, said composite membrane having been formed by a process including the steps of: (1) impregnating a porous substrate with an impregnation fluid that is essentially immiscible with a perfluorinated solvent; (2) coating the impregnated porous substrate with a solution that includes a perfluoropolymer and the perfluorinated solvent; and (3) removing said perfluorinated solvent and the impregnation fluid to form a perfluorinated polymer coating on said porous substrate, thereby forming said composite membrane, whereby said fraction enriched in the first component and said fraction depleted in the first component are generated by preferentially permeating a portion of said fluid mixture through said composite membrane.