AIR SEPARATION METHOD AND APPARATUS

摘要

A method and apparatus for separating air by cryogenic rectification in which cooled, compressed and purified air is separated in a distillation column system having higher and lower pressure columns operatively associated with one another in a heat transfer relationship to produce an oxygen-rich liquid stream from the lower pressure column. The oxygen-rich liquid stream is pumped and heated through indirect heat exchange with a compressed heat exchange stream to form a pressurized oxygen product stream. Part of the air is sequentially and successively compressed in booster compressors driven by turboexpanders to form the compressed heat exchange stream while other parts of the air are expanded in turboexpanders driving the booster compressors to form exhaust streams that are introduced into both the higher and lower pressure columns to generate refrigeration.

主权项

1. A method of separating air within a cryogenic rectification process, said method comprising:
separating the air in the cryogenic rectification process by cooling the air, after having been compressed and purified and rectifying the air in a distillation column system having a higher pressure column and a lower pressure column operatively associated within one another in a heat transfer relationship to produce return streams enriched in components of the air that are warmed through indirect heat exchange with the air to help cool the air and to produce product streams; one of the product streams formed by withdrawing an oxygen-rich liquid stream from a bottom region of the lower pressure column, pumping at least part of the oxygen-rich liquid stream to produce a pumped liquid oxygen stream and heating at least part of the pumped liquid oxygen stream to form a pressurized oxygen product stream, the at least part of the pumped liquid oxygen stream constituting one of the return streams and the at least part of the pumped liquid oxygen stream heated through indirect heat exchange with a compressed heat exchange stream composed of part of the air to be cooled and rectified in the distillation column system; forming the compressed heat exchange stream, a first exhaust stream and a second exhaust stream with the use of a first booster loaded expander and a second booster loaded expander having booster compressors driven by turboexpanders by sequentially compressing the part of the air within the booster compressors of the first booster loaded expander and the second booster loaded expander to form the compressed heat exchange stream and partially cooling and then expanding other parts of the air within the turboexpanders to produce a first exhaust stream and a second exhaust stream from expansion of the other parts of the air within in the first booster loaded expander and the second booster loaded expander, respectively; and introducing the first exhaust stream into lower pressure column and the second exhaust stream into the higher pressure column, thereby to impart refrigeration into the cryogenic rectification process.