Porous hollow fiber supported dense membrane for hydrogen production, separation, or purification
A dense hydrogen-permeable layer, such as palladium or palladium alloy, is deposited on a porous hollow fiber. A porous hollow fiber is defined as having an inner diameter of approximately 30 microns to approximately 1500 microns and an outer diameter of approximately 100 microns to approximately 2000 microns. This allows an order-of-magnitude increase in the surface per volume ratio in a hydrogen separation or purification module, or a membrane reformer or reactor.
1. A method of removing hydrogen in situ from a reactor or catalyst system producing hydrogen, the method comprising the steps of:
contacting a hollow fiber membrane with a reaction gas mixture, the membrane comprising a porous stainless steel support having an inner diameter of approximately 30 microns to approximately 1500 microns, an outer diameter of approximately 100 microns to approximately 2000 microns, an intermediate layer of ceramic coated on the stainless steel support, and a hydrogen selective dense layer coated on the outer diameter, the reaction gas mixture comprising either methane and steam or carbon monoxide and steam;
recovering a high purity hydrogen stream from a permeate side of the membrane; and
recovering a hydrogen-lean stream from a non-permeate side of the membrane.
2. The method of claim 1 , wherein the hydrogen-selective dense layer is selected from the group consisting of palladium, vanadium, tantalum, niobium, and cermet, mixtures of two or more of palladium, vanadium, tantalum, niobium, and cermet, as well as compounds, alloys, and composites that include one or more of palladium, vanadium, tantalum, niobium, and cermet.
3. The method of claim 2 , wherein the palladium hydrogen-selective dense layer comprises either palladium or a palladium alloy.