| 摘要 |
In a process for the separation of air by cryogenic distillation, air is purified, cooled and sent to a first distillation column (100) of a column system (ASU) wherein it is separated into an oxygen enriched liquid (10) and a nitrogen enriched gas, oxygen enriched liquid or a liquid derived therefrom is sent from the first column to a top condenser (107) of a second column (102) operating at a lower pressure than the first column and is partially vaporized, the bottom of the second column is warmed via a bottom reboiler (106), liquid (60) from the bottom of the second column is sent to an intermediate point of a third column (103) operating at a lower pressure than the second column, nitrogen enriched liquid (23) from the top of the second column is sent to the top of the third column, oxygen rich liquid (30) is removed from the bottom of the third column, pressurized (120) and vaporized by heat exchange with air and oxygen enriched liquid (24) from the top condenser of the second column is sent to an intermediate point of the second column (102) to be separated therein. |
