Liquid nitrogen washing device and method for recycling methane

Abstract

The invention discloses a liquid nitrogen washing device for recycling methane and a liquid nitrogen washing method for recycling methane, and in particular discloses a liquid nitrogen washing device for recycling methane by using a dual-reflux methane concentration column. The liquid nitrogen washing device comprises a gas-liquid separator I, a gas-liquid separator II, a medium-pressure nitrogen cooler, a raw material gas cooler I, a raw material gas cooler II, a methane concentration tower, a gas mixer, a nitrogen washing column and a hydrogen separator, wherein the interior of the methanol concentration column is divided into a first reflux washing section and a second reflux washing section, and is filled with filler; the interior of the nitrogen washing column is a liquid nitrogen washing section and is filled with filler. By adopting the liquid nitrogen washing device and method, methanol in a raw material gas can be recycled as a natural gas while an ammonia synthesis gas is refined, so that energy consumption and investment can be effectively reduced, good economic benefits can be made, and high environmental-friendliness and security coefficients can be achieved.

Description

technical field [0001] The invention relates to a liquid nitrogen washing process capable of recovering methane, in particular to a liquid nitrogen washing device using double-reflux methane concentration towers for methane recovery. Background technique [0002] Liquid nitrogen washing is a physical absorption process. Impurities such as carbon monoxide, methane, and argon contained in the raw material gas are absorbed into the solvent liquid nitrogen at low temperature, and the purified raw material gas is then mixed with nitrogen to meet the hydrogen-nitrogen ratio requirements of the downstream ammonia synthesis unit. [0003] Liquid nitrogen washing is one of the important processes for producing synthetic ammonia from coal. The liquid nitrogen washing device removes harmful impurities such as carbon monoxide and carbon dioxide in the synthesis gas, prolongs the life of the ammonia synthesis catalyst, and removes methane, argon and other impurities at the same time. Mo...

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Problems solved by technology

[0005] In view of the current problems, the object of the present invention is to provide a liquid nitrogen scrubber and its method capable of recovering methane. Through the liquid nitrogen scrubber, the methane component in the raw material gas is condensed into a solid through a cryogenic process. , causing the blockage of the cold box, economically separated and used as natural gas to improve the overall economic benefits of the project

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