| 摘要 |
PURPOSE:To eliminate the disadvantages of a prior art and to reduce operating cost by reducing the quantity of a dangerous substance like hydrocarbon such as methane, ethane, propane, etc., of a main condensing evaporator to the vapor pressure or less of the hydrocarbon at an oxygen evaporating temperature. CONSTITUTION:A cleaning unit 22 for cleaning to remove hydrocarbon included in rising gas with falling liquid is provided in the lower part of an upper tower 21. Liquefied oxygen is extracted from the upper part of the unit 22, supplied to a main condensing evaporator 23, heat exchanged with nitrogen gas in the evaporator 23 to vaporize the liquefied oxygen, which is introduced to the lower part of the unit 22, and the liquefied oxygen is discharged from the bottom of the tower 21. |
