Method and system for synthesizing methane, gasoline and diesel from low-rank coal and biomass

Abstract

The invention provides a method and a system for synthesizing methane, gasoline and diesel oil by using low-rank coal and biomass as raw materials. The method comprises: coking the low-rank coal to obtain a solid semicoke product and a gaseous product, and separating pyrolysis gas and tar from the gaseous product; gasifying the solid semicoke product to obtain semicoke gasified synthesis gas; gasifying the biomass to obtain biomass gasified synthesis gas; mixing the pyrolysis gas, the semicoke gasified synthesis gas and the biomass gasified synthesis gas, performing Fischer-Tropsch reaction, and then separating the obtained oil and gas to obtain synthetic oil and unconverted gas; mixing the obtained synthetic oil and tar, distilling to obtain fractions of which the temperatures are less than 180 DEG C, 180-320 DEG C and more than 320 DEG C, hydrotreating the fractions and separating out light hydrocarbons of which the carbon atom numbers are within 4; and mixing the light hydrocarbons of which the carbon atom numbers are within 4 and the unconverted gas to synthesize the methane. The method is favorable for developing the low-rank coal on large scale, and the economic benefits of the system are improved.

Description

technical field [0001] The invention relates to a method and system for synthesizing methane, gasoline and diesel with low-rank coal and biomass as raw materials, belonging to the technical field of energy fuel and chemical production. Background technique [0002] Clean coal conversion technologies using coal-to-synthetic fuels will undoubtedly dominate the share of alternative oil production. Compared with the direct liquid technology, the indirect liquid fuel technology in the coal-to-liquid fuel technology route, that is, the Fischer-Tropsch synthesis process using coal gasification synthesis gas as raw material, can more easily realize the production of sulfides, nitrogen oxides, heavy hydrocarbons and heavy metals. content of qualified emissions. However, there are many restrictive factors in the large-scale application of Fischer-Tropsch synthesis technology. For example, at present, the most research is to use anthracite, bituminous coal and other coals with better...

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Problems solved by technology

[0004] On the other hand, for the indirect coal liquefaction technology that directly uses coal-based syngas as raw material to produce synthetic liquid fuels, if no greenhouse gas emission reduction treatment is performed, the greenhouse gas emissions in the generalized fuel cycle process will be equal to that of traditional crude oil refining liquid. about twice as many fuel routes, resulting in a greater negative impact on the environment

If the greenhouse gas emission reduction technology is applied, the energy and economic costs will greatly weaken its competitiveness with the traditional petroleum-to-liquid fuel route

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