Patent ID: 6139604
Filing Date: 2000-10-31
Classification: B01D,C01B,Y02C,Y02P

Abstract:
A low energy cost process for the production of oxygen and nitrogen from a feed gas containing a mixture of oxygen and nitrogen that comprises the steps of:compressing said feed gas in an air compressor to produce a compressed feed gas;contacting said compressed feed gas with a cathode side of an oxygen selective ion transport membrane, said feed gas being at a first temperature that is effective to promote pressure driven transport of elemental oxygen from said cathode side to an anode side of said oxygen selective ion transport membrane after which a retentate containing nitrogen rich product gas remains on said cathode side;dividing said retentate into a first oxygen depleted portion at a first flow rate and a second oxygen depleted portion at a second flow rate;recovering a high pressure nitrogen rich product gas from said first oxygen depleted portion;expanding said second oxygen depleted portion in a turbine thereby generating a combination of work and a turbine exhaust of a low pressure nitrogen rich product gas whereby, in said dividing step, said first flow rate is selected to enable said turbine to provide sufficient work to drive said compressor; andrecovering oxygen product gas from a permeate on said anode side of said oxygen selective ion transport membrane.