Process for producing liquefied natural gas by using coke-oven gas

Abstract

The invention discloses a process for producing liquefied natural gas by using coke-oven gas, and belongs to the field of liquefied natural gas production. The process comprises the steps of raw material mixing, initial compression, pretreatment, purification, recompression, methanation, drying for mercury removal, cryogenic liquefying and separation, storage of liquefied natural gas, and truck loading of liquefied natural gas. Compared with the prior art, the process for producing liquefied natural gas by using coke-oven gas disclosed by the invention can produce qualified liquefied natural gas by using coke-oven gas, and the liquefied natural gas can be conveniently transported and utilized, thereby enhancing the added value of the coke oven gas; the production cost is effectively reduced, the economic benefit is improved, and the environment pollution is reduced.

Description

technical field [0001] The invention relates to the field of liquefied natural gas production, in particular to a process for producing liquefied natural gas by using coke oven gas. Background technique [0002] my country is the world's largest coke producer, and the by-product coke oven gas produced every year is about 40-60 billion Nm 3 / Year. In typical coke oven gas composition, H 2 54~59% (volume fraction, the same below), CH 4 21~25%, CO 5~8%, CO 2 1.9~2.3%, C m h n 1.6~2.0%, N 2 2~6%,O 2 0.3-0.7%, and contains tar, benzene, naphthalene, ammonia, hydrogen cyanide, hydrogen sulfide, organic sulfur and other impurities. Coke oven gas contains more effective components, but also has many impurities. At present, most coke oven gas is used to produce methanol, dimethyl ether, hydrogen, ammonia and domestic gas after purification, and some of them are directly released. [0003] Liquefied natural gas, referred to as LNG, is mainly composed of methane. It is a ...

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Problems solved by technology

[0005] At present, there have been patents disclosing the technology related to the production of liquefied natural gas from coke oven gas. For example: CN195 2082A uses the pressure swing adsorption method to separate and recondense the compressed coke oven gas to produce LNG. The methane gas contained in the furnace gas does not make full use of the CO and CO in the coke oven gas 2 and H 2 , so that the methanation reaction produces methane, resulting in a waste of resources; CN10170 9237 A uses membrane separation to separate the methanated coke oven gas from the incompletely reacted hydrogen and then produces liquefied natural gas through recondensation. The disclosed patent methane The yield is low; CN101100622 A and CN101921641A produce synthetic natural gas through pretreatment, desulfurization, methanation, and PSA. The natural gas disclosed in the above two patents has not been liquefied, and the volume of natural gas is large, difficult to transport, and high logistics costs