Method and device for preparing liquefied methane by using synthesis ammonia tail gas

Abstract

The invention discloses a method and a device for preparing liquefied methane by using synthesis ammonia tail gas. The method comprises the following steps of: 1, removing the synthesis ammonia tail gas and harmful gas which is exhausted during the production of synthesis ammonia in carbon dioxide gas, pressurizing the synthesis ammonia tail gas and/or the carbon dioxide gas to ensure that the pressure of the two kinds of gas is consistent, and mixing; 2, introducing the mixed gas into a methanation reaction furnace for reaction to ensure that carbon dioxide is reacted with hydrogen to produce methane and water; 3, introducing the reacted gas into a gas purifying device to remove the water and the carbon dioxide in the gas; and 4, introducing the purified gas into a methane liquefaction device, liquefying methane gas by cooling and rectification processes, separating the liquefied methane out of the methane liquefaction device, storing and packaging. In addition, the gas separated out of the methane liquefaction device can be introduced into an argon liquefaction device to prepare liquid argon. By the method, energy in the emptied tail gas is recycled, and the exhaust amount of greenhouse gas is reduced.

Description

technical field [0001] The invention relates to the field of recovery and comprehensive utilization of chemical tail gas, in particular to a method for recovery and utilization of synthetic ammonia tail gas and an utilized device. Background technique [0002] The tail gas emitted by the synthetic ammonia plant contains methane, nitrogen, hydrogen, argon and ammonia, etc. At the same time, carbon dioxide is also emitted during the production of synthetic ammonia. However, there is no good method to deal with the tail gas of synthetic ammonia in China. At present, the tail gas of synthetic ammonia in nitrogen fertilizer plants is burned or directly vented. This method not only wastes energy, pollutes the environment, but also reduces the economic benefits of nitrogen fertilizer plants. The beneficial methane and argon therein cannot be recovered. In addition, the carbon dioxide produced in the production of synthetic ammonia is usually directly vented, which will inevitably ...

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Problems solved by technology

[0004] The technical problem to be solved by the present invention is to propose a method and device for producing liquefied methane by using synthetic ammonia tail gas, so a

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