METHOD FOR UNDERGROUND COAL GASIFICATION WITH ELECTRIC POWER GENERATION Russian patent published in 2024 - IPC E21B43/295 F02C3/20 E21F7/00 

FIELD: various technological processes; gas industry.

SUBSTANCE: invention relates to underground coal gasification with electric power generation. Method involves generation of combustible synthesis gas by oxygen gasification of coal directly in the depths of the underground gas generator using a series of blowing and gas discharge wells from the surface of the earth and using the obtained synthesis gas as fuel for the oxygen-fuel power cycle using carbon dioxide as the working medium. Excess working medium of carbon dioxide is buried in spent underground gas generator. For underground coal gasification and combustion of produced synthesis gas oxygen with purity of more than 99.5 % is used, produced by a single air separation unit for this process complex and supplied for coal gasification and into the combustion chamber. Working medium of the power cycle is the products of oxy-combustion of synthesis gas produced in the process of underground gasification of coal, which is preliminarily cleaned from mechanical and resinous impurities, the basis of which is carbon dioxide. Cycle working medium consisting of carbon dioxide and water vapor is directed from the combustion chamber to the turbine inlet. After the turbine, the working medium enters the hot end of the regenerative heat exchanger, from which the remaining carbon dioxide enters the pressure boosting unit. Thereafter, carbon dioxide removed from the power cycle is divided into four flows. First flow for recirculation in the power cycle, returning to the cold end of the heat exchanger. Second flow is used to cool turbine parts. Third flow is intended for enrichment of blast of underground gas generator with carbon dioxide gas. Fourth flow is for burial in the spent underground gas generator. Method also involves capturing and recycling not only carbon dioxide at the stage of producing synthesis gas, but also at the stage of its energy use.

EFFECT: prevention of greenhouse gas emissions into atmosphere and necessity to extract coal from subsoil during development of coal deposits and generation of electric power.

1 cl, 1 dwg