CRYOGENIC AIR SEPARATION SYSTEM FOR ENHANCED LIQUID PRODUCTION

摘要

Argon, oxygen and nitrogen contained within an incoming air feed (10) is fractionated within an air separation system having a multiple column arrangement (32) that includes a higher pressure column (30) and a lower pressure column (34) to produce oxygen and nitrogen-rich fractions and an argon column (90) to produce an argon-rich fraction for recovery of the argon as an argon product. A two-phase stream (132; 134) can be formed by either expanding at least part of a liquid air stream (82) or by a liquid oxygen column bottoms (132) formed within a higher pressure column (30) of the multiple column arrangement (32). The liquid air stream (82) is formed by liquefying part of the air feed (22) to be fractionated against vaporizing a pumped liquid stream (76) composed of nitrogen and/or oxygen. The diversion of nitrogen vapor (146; 166) contained in the nitrogen-rich fraction increases the liquid to vapor ratio within the lower pressure (34) column to increase the argon recovery.