| 摘要 |
PROBLEM TO BE SOLVED: To manufacture oxygen as a recovery yield of oxygen is maintained by a method wherein condensed oxygen rich liquid air is used as raw material liquid and reflux liquid for an oxygen rectifying tower. SOLUTION: A liquid phase part of raw material air fed to a first rectifying tower 10 gathers at the bottom of a first lower air part 13, an air phase part is raised through a first rectifying tower 10 and effects counterblow with reflux flow the component of which is liquid nitrogen to effect contact of air and liquid with each other. Nitrogen gas gathers in a first upper space part 11 and oxygen rich liquid air gathers in a first lower space part 13. A part thereof is introduced to an expansion valve 31 for reduction of a pressure and fed to a nitrogen condenser 14 as a refrigerant and thereafter, fed as a refrigerant to a nitrogen condenser 14. Thereafter, it is introduced to a reboiler 24 to heat liquid in a second lower space part 23 and introduced to an expansion valve 33 through a piping 121 and expanded to produce a gas liquid mixture, which is introduced to the upper part of a rectifying tower 22 of a second rectifying tower 20 and treated into a substance similar to an air liquid mixture introduced through a piping 102. As a result, nitrogen gas containing a component having boiling point lower than that of oxygen gathers at a second upper space part 21, and liquid oxygen gathers in a second lower space part 23.
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