| 摘要 |
1,245,622. Cold separation of air. HYDROCARBON RESEARCH Inc. 5 Dec., 1968 [12 March, 1968], No. 57864/68. Heading F4P. In a compressed air rectification process for the production of liquid oxygen and liquid nitrogen wherein feed air in a line 16 is cooled in heat exchangers 14, 15 traversed by counterflowing cold effluent nitrogen and oxygen withdrawn from a low pressure column 28 through lines 42, 38 respectively and wherein refrigeration is supplied by withdrawing through a line 41 high pressure nitrogen from a column 18, warming it to a temperature between ambient and the minimum temperature of the process and work-expanding in a turbine 58, a first portion 45 of the nitrogen stream which is controlled by a by-pass valve 52 is warmed in exchanger 15 whilst a second portion 48 is warmed at 54 in heat exchange with a gaseous stream at ambient temperature and the two portions and also the by-passed portion of high pressure nitrogen are recombined prior to expansion at 58. The cold expanded nitrogen in a line 59 is added to the nitrogen effluent from column 28 prior to its passage through exchangers 14, 15. As shown the warm gas stream which is cooled in exchanger 54 comprises product gaseous oxygen having been withdrawn from the low pressure column 28 through lines 38, 60 and exchangers 14, 15, compressed at 62 to such a pressure that it condenses at 58. The liquid oxygen may be withdrawn at 69 or expanded at a valve 72 into the column 28. In a modification warm nitrogen in a line 44 may be compressed and passed through exchanger 54 or the warm stream may be an extraneous stream 61. Product liquid oxygen may be withdrawn from the column 28 through a line 70 and product liquid nitrogen may be drawn from column 18 through a line 73.
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