Cryogenic system for producing low-purity oxygen

摘要

Low purity oxygen is produced by factional distillation of liquefied air in a double distillation column and an auxiliary distillation column. Feed air is supplied at two different pressures. The disclosed methods of handling intermediate oxygen-enriched liquid produced by the two columns and removing nitrogen-rich gas from the auxiliary distillation column permit the system to operate with lower energy requirements and smaller column diameter than conventional systems.