Fast response high purity membrane nitrogen generator

摘要

A process for generating a nitrogen-enriched gas from a feed stream of atmospheric air or a mixture of nitrogen which is not continuously supplied to a membrane system, which membrane system comprises a non- permeate side and a permeate side, and being more permeable to oxygen than nitrogen, which process entails feeding the feed stream side of the membrane, and recovering an oxygen enriched gas being recovered on the permeate side of the membrane system while a nitrogen- enriched gas is recovered from the non-permeate side of the membrane, wherein a feed back of nitrogen gas or nitrogen- containing gas having an oxygen gas concentration lower than 21% is supplied to the non-permeate side of the membrane system during at least a part of the period of time where the air feed stream is not supplied to the membrane system thereby avoiding any substantial retrodiffusion of oxygen through the membrane system from the permeate side to the non-permeate side of the membrane during those periods of time where the feed stream is not supplied to the membrane system.