| 摘要 |
The present invention is an improvement to a cryogenic distillation process for the separation of air into its constituent components. The present invention process uses a distillation column system which comprises at least two distillation columns wherein the top of the higher pressure column is in thermal communication with the lowerpressure column. The distinctive feature and improvement of the present invention comprise: (a) condensing a portion of the compressed, contaminant-free, feed air by appropriate means, such as against vaporization of liquid oxygen or other source of refrigeration; (b) using at least a portion of this liquid air as impure reflux in one of the distillation columns, and (c) removing a waste vapor stream from a location situated no more than four theoretical stages above the location where the liquid air is fed to the column, such that this waste vapor stream has a nitrogen mole fraction of less than 0.95.
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