Underground coal gasification method and underground coal gasification system

Abstract

The invention aims at providing an underground coal gasification method and an underground coal gasification system. The underground coal gasification method is characterized in that standby gas is stored in an air combustion unit after the gasification completion, and when the yield of raw gas generated by the current gasification unit is insufficient or the volume percent of combustible gas in the raw gas is not inconsistent with a preset value, the raw gas gasified by the current gasification unit is mixed with the standby gas, so that the raw gas with the combustible gas volume percent conforming to the preset value is continuously conveyed to a raw gas treatment system. The underground coal gasification system is used for gasifying the subsequent underground coal bed into the raw gas, in addition, the raw gas is supplied to the raw gas processing system, the underground coal gasification system comprises the gasification unit and the air consumption unit communicated with the gasification unit, and the raw gas with the combustible gas volume percent higher than the preset value is stored in the air consumption unit as the standby gas.

Description

technical field [0001] The invention relates to the technical field of coal mining, in particular to an underground coal gasification method and an underground coal gasification system. Background technique [0002] Underground coal gasification is a new technology for comprehensive energy production that integrates multiple disciplines. It is a second-generation coal mining method. Its task is to convert underground coal resources into raw coal gas in situ. The main component of raw coal gas is hydrogen. , carbon monoxide, methane. [0003] An existing underground coal seam gasification method comprises the steps of: establishing a gasification channel in the coal seam to be gasified; arranging a plurality of explosive devices in the coal seam to be gasified, and the plurality of explosive devices correspond to the A plurality of coal seam sections of the coal seam to be gasified; igniting or igniting in the gasification channel to start the gasification process; The coal...

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Problems solved by technology

[0004] Due to the existence of various unpredictable conditions such as the environmental pressure of the gasification unit of underground coal gasification, groundwater, etc., the raw gas output and raw gas quality will fluctuate in the large-scale production process of underground coal gasification. It can meet the production requirements of the raw coal gas purification system and synthesis system in the normal production stage and on the ground, and can achieve certain economic benefits. Coal gas composition and gas production will be greatly reduced during the underground coal seam end stage) and underground gasification unit maintenance, which will lead to the low load operation of the raw gas purification system and synthesis system, and even lead to the outage of the post-system. In the early stage of ignition of the underground gasification unit, the end of production and the maintenance of the underground gasification unit, the purification system and synthesis system of the raw gas will increase the cost of purification and synthesis of the raw gas due to low load and low yield, and even cause losses

A start-up and shutdown of the specific raw gas purification system and synthesis system may cause hundreds of thousands or millions of losses

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