Method and apparatus for producing oxygen

摘要

A, filtered, compressed and purified air stream is divided into first and second air streams 18 and 20 respectively. The first air stream is separated by a low temperature rectification process operating in accordance with a Claude cycle to produce liquid oxygen in a lower pressure column 28 of a double column air separation unit. A Claude expander 24 expands at least a major portion of the first air stream into the high pressure column 28. The second air stream 20 is further compressed in a booster-compressor 60, is cooled in a main heat exchanger 20 and is expanded in a turboexpander 64 with the performance of work which is in turn applied to the work of compression of the second air stream. Liquid oxygen is pumped by pump 72 from a lower pressure column 36 to substantially a desired delivery pressure and is vaporized within a mixing column 68 by countercurrent contact the second air stream 20 which is also introduced into the mixing column. A liquid stream composed of the liquid produced in the mixing column is introduced into an intermediate location of a lower pressure column 36 to add the refrigeration of the second air stream to the process. $$