| 摘要 |
In a process of and a system for liquefying air to separate its components employing a so-called compound fractionating column, the system includes a fractionating medium pressure column into which a part of feed air is introduced to flow therethrough as an upwardly flowing gas for contact with a returning liquid, so as to obtain nitrogen gas at the top thereof and change the returning liquid to liquefied air as it reaches the bottom thereof, a first condenser adapted for a heat exchange between a liquefied air of a reduced pressure, which has been obtained by allowing an expansion of the liquefied air available at the bottom of the medium pressure column, and the nitrogen gas obtained at the top of the medium pressure column, so as to liquefy the nitrogen gas to make use of it as the returning liquid for the medium pressure column, a second condenser adapted for a heat exchange between the remainder part of feed air and liquefied oxygen to evaporate the oxygen, and a fractionating low pressure column through which the evaporated oxygen is made to flow as an upwardly flowing gas adapted to be contacted by a returning liquid coming down from the top of the low pressure column for a fractionation, whereby an impure gas is obtained at the top of the low pressure column, while the returning liquid is changed to liquefied oxygen as it reaches the bottom of the low pressure column.
|
