Patent ID: 6279344
Filing Date: 2001-08-28
Classification: F25J

Abstract:
A method for producing oxygen comprising:(A) passing feed air into a higher pressure column and separating the feed air by cryogenic rectification within the higher pressure column into nitrogen-enriched vapor and oxygen-enriched fluid;(B) passing oxygen-enriched fluid from the higher pressure column into a lower pressure column and producing oxygen-richer fluid within the lower pressure column;(C) passing oxygen-richer fluid from the lower portion of the lower pressure column into the upper portion of a side column and producing oxygen-rich liquid within the side column;(D) withdrawing nitrogen-enriched vapor from the higher pressure column, compressing the nitrogen-enriched vapor, and cooling the compressed nitrogen-enriched vapor by indirect heat exchange with oxygen-rich liquid to produce oxygen-rich vapor; and(E) recovering vaporized oxygen-rich liquid as product oxygen.