Method for producing tar and co-producing LNG (Liquefied Natural Gas) through powdered coal pyrolysis and fine coke gasification coupling

Abstract

The invention discloses a method for producing tar and co-producing LNG (Liquefied Natural Gas) through powdered coal pyrolysis and fine coke gasification coupling. The method comprises the following steps of (1) performing powdered coal pyrolysis on powdered coal to generate fine coke and raw coke oven gas; (2) recycling the tar and clean gas by performing gas purification on the raw coke oven gas generated in the powdered coal pyrolysis, using a part of the clean gas to supply heat for the powdered coal pyrolysis, and using a part of the clean gas to conduct follow-up processing and production of the LNG; (3) generating synthesis gas by gasifying the fine coke generated in the powdered coal pyrolysis; (4) obtaining clean mixed gas by leading the clean gas and synthesis gas obtained by the powdered coal pyrolysis and the gas purification to be subjected to sulfur-tolerant shift and low-temperature methanol desulfuration and decarburization, and using the clean mixed gas as a methanation raw material; (5) obtaining high methane gas after leading the clean mixed gas to be subjected to methanation; and (6) obtaining an LNG product with a methane content greater than 99 percent and exhaust gas that mainly comprises hydrogen and nitrogen after leading the high methane gas to be subjected to deep-cold liquefying separation, and using the exhaust gas to supply heat for the powdered coal pyrolysis. By the method disclosed by the invention, not only is the quality-based utilization of powdered coal achieved, but also the problem of fine coke use is solved, and the industrial chain is extended; and systemic waste heat can be reasonably used for generating electricity, so that the energy consumption is reduced.

Description

technical field [0001] The invention belongs to the technical field of energy development, and relates to a method for producing tar and co-producing LNG by coupling pulverized coal pyrolysis and pulverized coke gasification. Specifically, pulverized coal is used as raw material, and pulverized coal pyrolysis is combined with gasification technology A method for producing tar and co-producing LNG. Background technique [0002] my country's oil-scarce, gas-scarce, and coal-rich energy structure characteristics determine that my country's energy consumption will be dominated by coal for a long time. At present, the degree of mechanized mining of coal mines is relatively high, and lump coal only accounts for about 30%. A large amount of cheap pulverized coal in major coal producing areas cannot be used effectively. [0003] The development of pulverized coal pyrolysis technology is one of the implementation of national energy diversification strategy. Pulverized coal pyrolysis...

AI Technical Summary

Problems solved by technology

In this method, the clean coal gas with relatively high methane content obtained by pyrolysis of pulverized coal is mixed with the synthesis gas generated by pulverized coke gasification to produce LNG. The production and operation cost and equipment investment cost of methanation catalyst replacement, and tar products are obtained, which realizes the separation and utilization of pulverized coal and solves the problem of utilization of pulverized coke

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