A device and method for directly producing methane based on coal chemical looping gasification

Abstract

The invention belongs to the technical field of preparation of substitutive natural gas from coal, and relates to a device and method for directly preparing methane based on coal chemical chain gasification. Pulverized coal particles pass through the upper portion of a chemical chain gasification reactor and enter a chemical chain gasification reactor, oxidation state multifunctional composite oxygen carrier particles and unreacted carbon in the pulverized coal particles enter a regeneration reactor on the upper portion of a coal methanation section through a first flowing control device, coal slag obtained after reacting is discharged through a slag discharging opening, gas separated by a cyclone separator sequentially passes through a gas purifying unit and a gas separation unit, methane gas is obtained, and coal ash obtained after separation of the cyclone separator, part of unreacted carbon and the oxidation state multifunctional composite oxygen carrier particles return to the chemical chain gasification reactor or the regeneration reactor again to be recycled. The device is simple in structure and convenient to operate, the process theory is scientific, the raw materials are easy to obtain, cost is low, thermal efficiency is high, the carbon utilization efficiency is high, fewer pollutants are generated, and environmental friendliness is achieved.

Description

Technical field: [0001] The invention belongs to the technical field of replacing natural gas with coal, and relates to a device and method for directly preparing methane based on coal chemical chain gasification, and is also applicable to other solid fuels such as coal coke, biomass and solid waste. Background technique: [0002] The characteristics of my country's fossil energy reserves are "rich in coal, poor in oil, and low in gas". For a long time to come, my country's primary energy consumption will be dominated by coal. In my country's energy production structure, coal accounts for 3 / 4, and in the energy consumption structure, coal accounts for 2 / 3. In the next 10-30 years, my country's primary energy will be dominated by coal. At present, the proportion of natural gas in primary energy consumption in my country is low, only 4.4% in 2012; while the proportion of primary energy consumption of natural gas in the world is 24%, and it reaches 34% in European and American ...

AI Technical Summary

Problems solved by technology

The reaction is an exothermic reaction and does not require a large amount of external heat to maintain the temperature of the reaction system. The thermal efficiency can be close to 80%, but the source of hydrogen in the reactants is the main problem; the catalytic steam gasification method uses alkali metal carbon Hydroxide or alkali metal hydroxide is used as a catalyst, and water vapor is used as a gasification agent to couple low-temperature catalytic gasification of coal and methanation of syngas in one reactor to directly generate methane-enriched gas, but this process has a slow reaction rate. , low carbon conversion rate, complex catalyst recovery process, greenhouse gas CO 2 Disadvantages such as large amount of generation

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