AbstractThe asymmetric flat sheet membrane was developed for separation of hydrogen from its mixtures with other gases. The composition of the casting solution and conditions of membrane preparation were optimized for the pilot scale membrane production. The resulting membrane have a high hydrogen flux (1 m3(STP)/m2h*bar) and selectivity of H2/CH4 at least 100, the value close to intrinsic selectivity of Matrimid 5218, material used for the asymmetric structure formation. The membrane is stable against mixtures of liquid hydrocarbons and can withstand heating up to 200 °C. The non-woven fabric used as a support for the asymmetric membrane gives to the membrane excellent mechanical properties and allows to use the membrane in GKSS gas separation modules.