PURPOSE: To develop a cryogenic rectification system for producing liquid oxygen having operating efficiency improved as compared with a conventional oxygen product boiler cycle.
CONSTITUTION: Supply air 100 is compressed by a compressor 1 and the majority (at least 55%) or the entirety of compressed supply air is passed through a compressor 5 coupled with a turbo expander 7 and compressed additionally. At least a part thereof is then subjected to turbo expansion and the remainder is passed through a product boiler 4 without being subjected to turbo expansion. The turbo expanded supply air is introduced into the high pressure column of a double column low temperature rectification system comprising the high pressure column 11 and a low pressure column 14. At least a part of supply air not subjected to turbo expansion is condensed and introduced into the high pressure column and liquid oxygen 23 is taken out from the low pressure column 14. The liquid oxygen is evaporated in the product boiler 4 through indirect heat exchange to produce oxygen which is recovered as a product 121.
ROBAATO AASAA BETSUDOOMU
DANTE PATORIKU BONAKISUTO
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