Hybrid nitrogen generator with auxiliary reboiler drive

Claim 1

A process for the production of nitrogen at relatively high yield and purity by cryogenic rectification of feed air comprising avoiding the need to employ a nitrogen recycle stream by the steps of: (a) introducing the major portion of the feed air into a rectification column which is operating at a pressure in the range of from 35 to 145 psia, and wherein feed air is separated into nitrogen-rich vapor and oxygen-enriched liquid; (b) condensing a minor portion of the feed air, at a pressure greater than that at which the column is operating, by indirect heat exchange with oxygen-enriched liquid; (c) introducing the resulting condensed minor portion of the feed air into the column at a point at least one tray above the point where the major portion of the feed air is introduced into the column; (d) condensing a first portion of the nitrogen-rich vapor by indirect heat exchange with vaporizing oxygen-enriched liquid; (e) passing at least some of the resulting condensed nitrogen-rich portion to the column at a point at least one tray above the point where the minor portion of the feed air is introduced into the column; and (f) recovering substantially the entire remaining second portion of the nitrogen-rich vapor as product nitrogen precluding the need for substantial recycle of any portion thereof back to the distillation column.