A method for preparing liquefied natural gas by sulfur-resistant methanation of coke oven gas

Abstract

The invention provides a method for preparing liquefied natural gas (LNG) through sulphur-tolerant methanation of coke-oven gas. The method is characterized by subjecting the coke-oven gas to direct three-stage methanation reactions on a supported molybdenum-based sulphur-tolerant methanation catalyst after removing the impurities such as oil, naphthalene, benzene and the like from the coke-oven gas, then removing the impurities such as sulphur, CO2, C2-4 hydrocarbons and the like once through rectisol, and finally separating N2, H2 and the like through one-time subzero liquefaction, thus obtaining the LNG with methane content higher than 97%. The method has the advantages of simple process flow, small equipment investment, low comprehensive energy consumption and excellent natural gas products.

Description

technical field [0001] The invention belongs to a method for preparing liquefied natural gas, in particular to a method for preparing liquefied natural gas by sulfur-resistant methanation of coke oven gas. Background technique [0002] my country is the world's largest coke producer, consumer and exporter. In 2012, my country's coke output reached 443 million tons, if one ton of coke produced 430m 3 Calculation of coke oven gas, the coke oven gas in that year alone reached 190.5 billion m 3 , of which about 70% of the coke oven gas is used for coke oven heating and domestic gas, while the remaining nearly 57 billion m 3 Coke oven gas has not been utilized, resulting in serious waste of resources and environmental pollution. Natural gas is a high-quality, efficient and safe clean energy. In recent years, with the rapid increase of natural gas demand in my country, the gap between domestic natural gas supply and demand has gradually increased, which in turn has restricted ...

AI Technical Summary

Problems solved by technology

In 2012, my country's coke output reached 443 million tons, if one ton of coke produced 430m 3 Calculation of coke oven gas, the coke oven gas in that year alone reached 190.5 billion m 3 , of which about 70% of the coke oven gas is used for coke oven heating and domestic gas, while the remaining nearly 57 billion m 3 Coke oven gas has not been utilized, resulting in serious waste of resources and environmental pollution

Patent CN101391935A discloses a method for synthesizing methane from coke oven gas. Through steps such as purification and dust removal, compression heat exchange, addition of water vapor, three-stage methane and PSA separation of methane, the product gas with a methane concentration of more than 90% is obtained, but this invention also The complex process of multi-stage hydrogenation and multi-stage desulfurization is adopted, and no effective method for simplifying the desulfurization process is given

Although the above-mentioned patents have improved the natural gas yield and separation effect to a certain extent by optimizing the process, they have not fundamentally solved the problems of coke oven gas synthesis of natural gas, especially the complex process flow, energy consumption and equipment investment of liquefied natural gas.

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