Process for preparing substitute liquefied natural gas (LNG) with coke-oven gas

Abstract

The invention provides a process for preparing substitute liquefied natural gas (LNG) with coke-oven gas. The process is characterized by subjecting the coke-oven gas to direct two-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 carrying out clean reaction through two-stage Ni-based methanation reactions after ferric oxide coarse desulfurization and activated carbon fine desulfurization, and finally separating the impurities such as N2, H2, H2O and little CO2 through subzero liquefaction, thus obtaining the LNG product with methane content higher than 97%. The process 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 the technical field of coal chemical industry, and in particular relates to a process for preparing liquefied natural gas from 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 by-product coke oven gas in that year alone was as high as 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. Coal-based 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 ha...

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 by-product coke oven gas in that year alone was as high as 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

The sulfur-tolerant methanation catalyst not only has the performance of methanation and organic sulfur hydrogenation, but also has the catalytic performance of water vapor shift and inverse water vapor shift. The water generated by methanation and the H of coke oven gas 2 The reverse water vapor shift reaction inevitably occurs and eventually reaches equilibrium, resulting in CO and CO in the syngas 2 It is difficult to completely convert, which affects the yield of natural gas, thereby limiting its industrialization and application

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