| 摘要 |
Air is separated by rectification. The air is compressed in a main air compressor 2 to a first pressure. Without further compression a first flow of the compressed air is cooled in a main heat exchanger 6 to a temperature suitable for its separation by rectification. The first flow is introduced into the higher pressure column 16 of a double rectification column 14 comprising, in addition to the higher pressure column 16, a lower pressure column 18, in which a bottom oxygen fraction containing from 50 to 96 mole per cent of oxygen is formed, and a condenser-reboiler 20 placing the higher pressure column 16 in heat exchange relationship with the lower pressure rectification column 18. A second flow of the compressed air is expanded with the performance of external work in an expansion turbine 32 without further compression of the second flow upstream of the expansion. The expanded second flow is introduced into the lower pressure rectification column 18. An impure oxygen product is taken from the said bottom fraction. The external work is the generation of electrical power, and thus the turbine 32 is coupled to an electrical generator 34.
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