Low energy consumption method for separating gaseous mixtures and in particular for medium purity oxygen production

摘要

A method for the separation of gaseous mixtures such as air and for producing medium purity oxygen, comprising compressing the gaseous mixture in a first compressor to about 3.9-4.1 atmospheres pressure, passing said compressed gaseous mixture in heat exchange relationship with sub-ambient temperature gaseous nitrogen, dividing the cooled, pressurized gaseous mixture into first and second streams, introducing the first stream into the high pressure chamber of a double rectification column, separating the gaseous mixture in the rectification column into a liquid oxygen-enriched stream and a gaseous nitrogen stream and supplying the gaseous nitrogen stream for cooling the compressed gaseous mixture, removing the liquid oxygen-enriched stream from the low pressure chamber of the rectification column and pumping the liquid, oxygen-enriched steam to a predetermined pressure, cooling the second stream, condensing the cooled second stream and evaporating the oxygen- enriched stream in an evaporator-condenser, delivering the condensed second stream to the high pressure chamber of the rectification column, and heating the oxygen- enriched stream and blending the oxygen-enriched stream with a compressed blend-air stream to the desired oxygen concentration.