| 摘要 |
A compressed stream of feed air is cooled in a main heat exchanger 4 and is introduced into a higher pressure rectification column 10 through an inlet 12. The air is separated in the column 10 to produce nitrogen vapour and oxygen-enriched liquid air. A stream of the latter is withdrawn from the column 10 through an outlet 40 and is separated into nitrogen and impure oxygen fractions in a lower pressure rectification column 18. Nitrogen produced in the higher pressure rectification column 10 is condensed in condenser-reboilers 24 and 48. Resulting condensate is used as reflux in the respective rectification columns 10 and 18. Reboil for the lower pressure rectification column 18 (which is operated at a pressure greater than 2 bar) in condenser-reboiler 16 is effected by heat exchange with a stream of feed air. Impure oxygen product is vaporised in the condenser-reboiler 24. <IMAGE> |
