In-situ gasification mining method of extremely thin coal seam group based on microwave radiation

Abstract

The invention discloses an in-situ gasification mining method of an extremely thin coal seam group based on microwave radiation. The in-situ gasification mining method comprises the steps that an airinlet well and an air outlet well are constructed from the ground to extremely thin coal seams by penetrating through rock strata; horizontal wells are constructed in the extremely thin coal seams through the air inlet well, wherein the horizontal wells penetrate through the air inlet well and the air outlet well; a microwave radiation well is constructed in the middle of the air inlet well and the air outlet well; the microwave radiation well, the air inlet well and the air outlet well all communicate with the horizontal wells in the coal seam group; O2 and H2O are injected into the coal seams through an air inlet pipeline; and water in a coal body is radiated by microwave, as water is an extremely-strong microwave absorber, microwave can rapidly heat the water, generated high-temperatureand high-pressure water vapor is beneficial to the development of coal fractures and heat transfer, and the high-temperature coal body is rapidly gasified after being in fully contact with reaction gas. The in-situ gasification mining method makes full use of the heat effect of microwave radiation to improve the in-situ gasification efficiency of the coal body, the process is simple, the operation is convenient, and the in-situ gasification mining method has wide practicability in the technical field of coal underground gasification.

Description

technical field [0001] The invention relates to an in-situ gasification mining method, in particular to an in-situ gasification mining method for extremely thin coal seam groups based on microwave radiation, and belongs to the technical field of underground coal gasification. Background technique [0002] In the field of coal mining, with the continuous improvement of mining intensity, the reserves of thick and medium-thick coal seams in some mines are decreasing day by day, and extremely thin coal seams have gradually become the main coal mining seams. Coal seams with a thickness below 0.8m are called ultra-thin coal seams. The geological structure of ultra-thin coal seams is complex and distributed in groups; the mining height is low, which is not conducive to the use of large-scale mining equipment; The economic benefits are extremely low. Therefore, the mining of extremely thin coal seams is extremely difficult. Underground coal gasification is the controlled combustio...

AI Technical Summary

Problems solved by technology

However, the traditional ignition method is complicated in process and high in energy consumption. Due to the extremely poor thermal conductivity of coal, the temperature rise rate of coal body is slow. In addition, the injected H 2 O It is difficult to maintain the gasification state. Due to the extremely low permeability of the coal body, it is difficult for the reaction gas to fully contact the coal body, resulting in difficulty in coal gasification

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