Air liquefaction and separation method and device

Abstract

Disclosed are a method and a device for liquefying and separating air, the price of a device used when fluid products are collected can be reduced. The method for liquefying and separating air is comprised of a raw material air compressing process wherein a compressed raw material air having a first setup pressure higher than the operating pressure of an intermediate pressure tower is obtained by compressing the entire amount of a raw material air, an absorbing and purifying process wherein a compressed and purified air is obtained by removing impurities from the compressed raw material air, a circulation air confluence process wherein a circulation air is obtained by joining the compressed and purified air and a compression returned air together, a cooling process wherein an air to be introduced to the intermediate pressure tower is obtained by cooling a first branch current air obtained by dividing the circulation air into two branch currents, so as to have a first setup temperature, and an air to be expanded is obtained by cooling a second branch current air so as to have a second setup temperature higher than the first setup temperature, an expansion process wherein a low-temperature air is obtained by adiabatically expanding the air to be expanded so as to have a second setup pressure lower than the first setup pressure, a process for introducing a part of the low-temperature air to the intermediate pressure tower, a temperature increasing process wherein a returning air is obtained by returning the temperature of the remaining low-temperature air, a circulating and compressing process wherein a compressed returning air is obtained by compressing the returning air, and a process for introducing the air to be introduced to the intermediate pressure tower to the intermediate pressure tower.

Description

technical field [0001] The present invention relates to a method and device for air liquefaction and separation. Specifically, it relates to air that extracts at least liquid oxygen as a product by performing low-temperature separation of compressed, purified, and cooled raw air in a medium-pressure tower and a low-pressure tower. Liquefaction separation method and device. Background technique [0002] In the case of industrial production of oxygen, nitrogen and argon, it is relatively difficult to manufacture oxygen, nitrogen and argon using a so-called low-temperature air liquefaction separation device that uses air as a raw material and separates it using a composite distillation column composed of a medium-pressure column and a low-pressure column. common. The low-temperature air liquefaction and separation device can use about 5% of the product to produce liquid oxygen, liquid nitrogen, and liquid argon. However, when more liquid products are produced, an additional l...

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Problems solved by technology

[0018] As mentioned above, many proposals have been made as a liquefaction process. In the air circulation liquefaction process, t

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