Device and method for catalyzing lignite to prepare methane directly

Abstract

The invention discloses a method and a device for catalyzing lignite to prepare methane directly. The method comprises the following steps: forming pulverized coal by raw material lignite, carrying out coal cracking, coal gasification, coal methanation and synthesis gas methanation reactions in a reaction furnace, to generate methane-enriched gas and coke, and processing the methane-enriched gas by a gas-solid separator and a gas separating device to obtain high-content natural gas; and reacting the coke generated in the reaction furnace with the waste gas carbon dioxide separated out by the gas purifying and separating device to generate carbon monoxide gas, inducing the generated carbon monoxide gas into the reaction furnace to participate the reaction, so as to realize the recycling of the carbon. The coal-made natural gas products can be obtained flexibly as required by the process, the process has the characteristics of high carbon conversation rate, clean products and the like; by utilizing the low-quality lignite with higher water content, the production cost is reduced further. The process for producing substitute natural gas by integration of gasification and methanation is a method with high economic benefit and high competitiveness.

Description

technical field [0001] The invention relates to a device and method for catalytically direct methane production from lignite, and belongs to the field of coal catalytic production of natural gas. Background technique [0002] With the rapid development of economy and society, as well as the increasingly stringent environmental protection requirements, the contradiction between my country's energy resource structure and energy consumption demand has become increasingly prominent. From 2000 to 2010, the average growth rate of national natural gas consumption reached 14.4%. It is predicted that the demand for natural gas will reach 170 billion cubic meters and 200 billion cubic meters in 2015 and 2020 respectively, correspondingly, the natural gas gap will be 65 billion and 100 billion cubic meters respectively, and by then, the dependence on natural gas will reach 50%. The current pattern of my country's natural gas supply not only restricts my country's economic and social d...

AI Technical Summary

Problems solved by technology

The characteristic of blue gas technology is to catalyze three reactions (gasification reaction, water gas shift reaction and methanation reaction) in one reactor, so as to realize the production of coal-to-SNG in one reactor, but the carbon utilization rate of blue gas technology is very low , there is too much difficulty in separating the catalyst and residue and the problem of catalyst deactivation, and there is no relevant feasibility report so far

[0006] Chinese Patent Publication No. CN102021037B "A Method and Device for Producing Methane from Coal Catalysis", this patent has more advantages than American blue gas technology, and is producing natural gas At the same time, it realizes the cracking of coal and better realizes the utilization of energy, but like the blue gas technology, it consumes a lot of water and the utilization rate of carbon is low

[0007] Chinese Patent Publication No. CN 101906339 A "Technology and Device for Integrated Coal Gasification and Methanation to Produce Alternative Natural Gas", this patent makes coal direct methanation and indirect The combination of methanation also has a good coupling in terms of energy, but the investment in follow-up equipment of this process is relatively large, and oxygen is introduced in the process of generating syngas, which not only increases the investment in air separation equipment, but also produces a large number of greenhouses. gas carbon dioxide

[0008] Chinese Patent Publication No. CN 102242006 A "A Process for Coal-to-Natural Gas and Its Method", which provides a direct hydrogenation of coal to methane This method greatly reduces the emission of greenhouse gas carbon dioxide, but the carbon conversion rate of this process is low, the methane yield is low, the gas composition is complex, and the process uses hydrogen with high cost, so the economic benefits are limited

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