| 摘要 |
PROBLEM TO BE SOLVED: To achieve a higher air separation efficiency by a method wherein precooled refined air is separated into an oxygen-enriched liquid and nitrogen vapor in a higher pressure rectifier, further separation of a stream of the oxygen-enriched liquid takes place to generate a liquid further enriched in oxygen and an intermediate vapor, and then a stream of the liquid further enriched in oxygen is separated into oxygen and nitrogen. SOLUTION: A stream of compressed air from a compressor 2 is sent to a refining device 4 to remove water vapor and carbon dioxide, the air stream after the refining is branched, and the first air stream passes through a main heat exchanger 6 to be cooled down to a saturation temperature. The air stream after being cooled is partially condensed by a condenser/reboiler 16 and then, introduced into a higher pressure rectifier 12 to take a stream of nitrogen vapor obtained out of the top part of the high pressure rectifier 12 so that it is condensed in another reboiler/condenser 22. Another stream of nitrogen vapor is condensed in an additional condenser/reboiler 28. On the other hand, a stream of a liquid enriched in oxygen is taken out of the bottom part of the higher pressure rectifier 12 and, after supercooled by a heat exchanger 38, it is flashed via a decompression valve 40 to obtain a liquid enriched in oxygen, which is introduced into a coarse separator 42. |
