| 摘要 |
<p>A method for producing gaseous oxygen, preferably at pressures in excess of 35 bars A, by the fractional distillation of air using a conventional double column having a high pressure column (6) and a low pressure column (11). Liquid oxygen is withdrawn from the bottom of the low pressure column (11) and is pressurized to lust above the desired product pressure by pump (13). The liquid oxygen is then vapourized in heat exchanger (15) using nitrogen from the top of the high pressure column (6). The nitrogen is compressed in compressor (28) to 41 bars A and in compressors (32 and 34) to 80 bars A. The stream (35) is sub-cooled in heat exchanger 15 and, after expansion at valve (36), the liquid nitrogen is returned to the high pressure column as reflux. The stream (31) is cooled in heat exchanger (15) and is expanded in an expander (40). The gas leaving the expander (40) is used to cool the stream (35) in heat exchanger (15) and is subsequently recycled to the inlet of compressor 28.</p> |
