Method for producing liquefied natural gas

Abstract

The invention discloses a method for producing liquefied natural gas. The method comprises the following steps of: (1) compressing and preheating virgin gas, and then deoxidizing to obtain deoxidized virgin gas; (2) introducing the deoxidized virgin gas into a purifying unit I to remove acid gas to obtain purified gas; (3) introducing the purified gas into a natural synthesis unit to react with methane to obtain crude synthesis gas; (4) introducing the crude synthesis gas into a purifying unit II for decarbonizing to obtain purified synthesis gas; (5) introducing the purified synthesis gas into a natural gas refining unit to remove H2O and CO2 to obtain nitrogen-rich natural gas; and (6) introducing the nitrogen-rich natural gas into a natural gas liquefying and separating unit for cooling and separating to obtain the liquefied natural gas. In the invention, low-heat-value blue carbon gas is converted into high-added-value clean fuel LNG (Liquefied Natural Gas) by adopting an advanced and reliable process technology, so the method has active effects on saving energy, reducing emission and protecting environment, conforms to the requirements of national industrial policies and environmental protection policies, enables enterprises to obtain considerable economic benefit and opens a new approach for the reasonable utilization of the blue carbon gas.

Description

technical field [0001] The invention relates to a method for producing liquefied natural gas, belonging to the technical field of chemical synthesis. Background technique [0002] In the process of producing semi-coke, a large amount of semi-coke tail gas is produced. According to the different coal quality, every ton of semi-coke (also called coal semi-coke) will produce semi-coke tail gas of 600~1000Nm 3 The calorific value is 1700-2200kcal. Compared with coke oven exhaust gas and coal bed methane, semi-coke exhaust gas is a low-quality heat source, and the calorific value per unit volume of gas is relatively low. At present, most of the semi-coke tail gas is directly evacuated and burned, and only a small part is used. The tail gas contains a large amount of H. 2 、CH 4 , CO and other effective gas components, it is a good gas energy source, but at the same time, semi-coke tail gas also contains harmful gases such as hydrogen sulfide and carbon dioxide and inert gases, d...

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Problems solved by technology

[0004] The purpose of this invention is to provide a method for producing liquefied natural gas to solve the environmental problems caused by tail gas discharge, and at the same time enable enterprises to obtain considerable economic benefits, and open up a new idea for the rational utilization of blue carbon tail gas and other waste gases

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