| 摘要 |
<p>Air is compressed in compressors 2, 6 and 8, cooled in a main heat exchanger 10, and separated into oxygen and nitrogen products in a double rectification column 20 comprising a higher pressure rectification column 22 and a lower pressure rectification column 24. A liquid oxygen product is withdrawn from the column 24 via a conduit 50. A liquid nitrogen product is also formed. An argon-enriched oxygen vapour stream is withdrawn from the column 24 through an outlet 54 and has argon separated from it in a column 42. In order to help meet the requirements of the column 20 for reflux, a nitrogen vapour stream is withdrawn from the top of the column 24, is warmed by passage through the heat exchanger 10, is recompressed in compressor 66, and is liquefied by passage back through the heat exchanger from its warm end 12 to its cold end 14 and passage through valve 70. A high liquid make and a high argon recovery can both be achieved. <IMAGE></p> |
