| 摘要 |
Air is separated in a double rectification column 22 comprising a higher pressure rectification column 16, a lower pressure rectification column 18, and a condenser-reboiler 20 placing the column 16 in indirect heat exchange relationship with the column 18. A stream of pressurised liquid, comprising oxygen and nitrogen, typically taken from the bottom of the higher pressure rectification column 16, is expanded through a valve 58 and is typically partially vaporised in a vaporiser-condenser 60 which is separate from a second vaporiser-condenser 68 in which argon is condensed. The vaporised liquid is expanded with the performance of external work in an expansion turbine 76 and is introduced into the lower pressure rectification column 18. An oxygen product is withdrawn from the column 18 through an outlet 88. <IMAGE> |
