Process and apparatus for the production of moderate purity oxygen

摘要

Oxygen (312) is produced by cryogenic separation of air using a multiple passage plate-fin heat exchanger having at least two sets of passages (202,204) to effectuate the rectifying (202) and stripping (204) functions. One set of passages (202) comprises a continuous-contact rectification dephlegmator which rectifies the feed air (300) and produces enriched-nitrogen rectifier overhead (316) and crude liquid oxygen bottoms (304). A second set of passages (204) comprises a continuous-contact stripping dephlegmator which strips oxygen-enriched liquid (310) to produce nitrogen-enriched stripper overhead (318) and the oxygen product (312). Reflux of the rectification device and boilup for the stripping device is provided, at least in part, by indirect heat exchange between and along said two sets of passages (202,204), thereby producing a thermal link between the rectification dephlegmator and the stripping dephlegmator.