摘要 |
Compressed, purified, vaporous air and liquid air streams are introduced into a higher pressure rectification column 18 through inlets 20 and 34, respectively. A stream of oxygen-enriched liquid flows from an outlet 46 of the higher pressure rectification column 18 via a reboiler 48 and an expansion valve 50 into a vessel 52. The oxygen-enriched liquid is partially vaporised in a boiler 54 located in the vessel 52. The residual liquid flows via an outlet 61 from the vessel 52 and a condenser 64 to an inlet 66 to a lower pressure rectification column 56 in which oxygen and nitrogen products are separated. A stream of vapour flows from the boiler 54 through an outlet 58 from the vessel 52 to a pipeline 60 which leads the air back for compression with incoming air. A greater yield of oxygen, and, if separated, argon is made possible by this recycle. <IMAGE> |