| 摘要 |
PURPOSE: To reduce the work being required at the time of compressing nitrogen by recirculating a part of nitrogen taken out from a low pressure column. CONSTITUTION: Compressed air is passed through a purifier 4 in order to remove steam and carbon dioxide therefrom and the main stream is passed through a heat exchanger 6 to lower the temperature down to cryogenic rectification level before being fed through an inlet 8 into a high pressure rectification column 10. A small quantity of air stream from the purifier 4 is compressed through a compressor 20 in a low pressure rectification column 12, cooled through a heat exchanger and introduced through an inlet 24 into the column 12. Oxygen rich liquid stream is withdrawn from the outlet 26 at the bottom of the column 10, supercooled through a heat exchanger 28 and passed through a Joule-Thomson valve 30 into the column 12. Gaseous oxygen product stream is then withdrawn from the bottom of the column 12 through an outlet 32 and a nitrogen product stream forms a compensatory circulation flow in the column 12 by withdrawing nitrogen rich component collected at the top of the column 10 and directly from the top of the column 12 through an outlet 36.
|
