Patent ID: 6125656
Filing Date: 2000-10-03
Classification: C09K,F25J

Abstract:
A method for the production of nitrogen gas and liquid nitrogen by the cryogenic rectification of feed air comprising:(A) compressing a multicomponent refrigerant fluid, cooling the compressed multicomponent refrigerant fluid, expanding the cooled, compressed multicomponent refrigerant fluid, and warming the expanded multicomponent refrigerant fluid by indirect heat exchange with said cooling compressed multicomponent refrigerant fluid and also with feed air to produce cooled feed air;(B) passing the cooled feed air into a cryogenic rectification column and separating the feed air by cryogenic rectification within the cryogenic rectification column into nitrogen-enriched vapor and oxygen-enriched liquid;(C) recovering a first portion of the nitrogen-enriched vapor as product nitrogen gas;(D) condensing a second portion of the nitrogen-enriched vapor to produce nitrogen-enriched liquid; and(E) recovering at least some of the nitrogen-enriched liquid as product liquid nitrogen.