Patent Number: 6,293,126

Title: Air separation

Abstract: A double column air separation method in which a first stream of compressed air is cooled by passage through a main heat exchanger from its warm end countercurrently to a nitrogen stream withdrawn from the top of a lower pressure rectification column. The first stream of compressed air flows from the main heat exchanger into a higher pressure rectification column through an inlet. A second stream of compressed air is also passed into the warm end of the main heat exchanger and is cooled therein. The second stream of compressed air passes out of heat exchange with the nitrogen stream at a temperature lower than the exit temperature therefrom of the first stream of compressed air and at least 5K lower than the bubble point temperature of air at the pressure prevailing at the inlet. A stream of oxygen-enriched liquid passes isenthalpically from the bottom of the higher pressure column to the lower pressure column.

Inventors: Higginbotham; Paul (Guildford, GB)

Assignee: The BOC Group plc

International Classification: F25J 3/04 (20060101); F25J 003/00 ()

Expiration Date: 09/25/2018