Process for synthesizing natural gas by performing methanation on coke oven gas

Abstract

The invention relates to a process for synthesizing natural gas by performing methanation on coke oven gas. The process comprises the following steps of: dispersing a fresh methanation catalyst into an inert liquid-phase medium and putting the mixture into a slurry bed methanation reactor for reducing; performing a methanation reaction on the reduced coke oven gas, introducing tail gas into a gas-liquid separator I, discharging a slurry liquid-phase component in the tail gas and the catalyst from the bottom of the gas-liquid separator I and exhausting a gas phase in the tail gas from the top of the gas-liquid separator I; introducing a part of catalyst-containing inert liquid-phase media into a gas-liquid separator II, exhausting a gas phase from the top of the gas-liquid separator II, combining the gas phase with the gas phase exhausted from the top of the gas-liquid separator I, cooling and performing pressure swing adsorption so as to obtain H2 and synthetic natural gas; and discharging a methanation catalyst-containing inert liquid-phase medium from the bottom, combining the methanation catalyst-containing inert liquid-phase medium with the slurry liquid-phase component and the catalyst which are discharged from the bottom of the gas-liquid separator I, filtering a large-particle catalyst of less than 300 meshes out, separating a fine catalyst of more than 300 meshes from the inert liquid-phase medium and discharging, mixing the separated inert liquid-phase medium and the large-particle catalyst, exchanging heat between the mixture and raw material gas, cooling, and introducing the mixture into the slurry bed methanation reactor together with the methanation catalyst which is newly dispersed into the inert liquid-phase medium for the methanation reaction. The process has the advantages that: the process has low energy consumption and small equipment investment, is easy to operate and can replace the catalyst on line.

Description

technical field [0001] The invention belongs to a process for synthesizing natural gas, in particular to a process for methanating coke oven gas to synthesize natural gas. Background technique [0002] As a kind of industrial exhaust gas, coke oven gas has a large output (in 2008, the total output of coke ovens in China was about 143 billion m 3 ), its recycling by methanation not only conforms to the policy requirements of energy conservation and emission reduction, but also can produce certain economic benefits. It is a technology with market prospects. [0003] The composition of coke oven gas (COG) is relatively complex and varies widely, depending on the properties of the coking coal used, coking methods and operating conditions. Its main composition (Vol) is: H 2 54-59%, CH 4 23-28%, N 2 3-5%, O 2 0.3-0.7%, CO 5.5-7%, CO 2 1.2-2.5%, C m h m 1.5-3%. H in coke oven gas 2 , CO, CO 2 Carrying out methanation reaction can produce artificial natural gas, and...

AI Technical Summary

Problems solved by technology

However, in order to control the temperature in the methanation process of this process, a large amount of circulating water vapor is introduced into the raw material gas, which increases energy consumption. It uses multi-stage adiabatic reactors, which also greatly increases the equipment

Images