| 摘要 |
<p>The invention concerns a method for separating air by cryogenic distillation in an installation comprising a medium pressure column ( 3 ), a low pressure column ( 4 ) and a mixing column ( 6 ). According to the method: air is compressed in a compressor (C 01 ); is cooled in an exchange line ( 1 ); a first portion ( 2 ) of the air is fed to the vessel of the mixing column; a second portion of the air is fed to the medium pressure column where it separates; an oxygen-enriched liquid ( 19 ) and a nitrogen-enriched liquid ( 11 ) are fed from the medium pressure column to the low pressure column; an oxygen-rich liquid ( 26 ) is fed from the low pressure column to the top of the mixing column; at least one flow of liquid ( 27, 29 ) is drawn off from the medium or low pressure column; the second portion of air is boosted in a booster ( 8 ); this air is cooled in the exchange line; it is divided into a first fraction and second fraction; the first fraction of air is cooled in the exchange line; it is at least partially liquefied and then sent to the medium pressure column and/or the low pressure column; the second fraction of air is expanded in a Claude turbine ( 9 ) and is fed to the medium pressure column, and; an oxygen-rich flow ( 18 ) is drawn off from the mixing column and is heated in the exchange line.</p> |
