Underground coal gasification deep hole ignition system and method

Abstract

The invention discloses an underground coal gasification deep hole ignition system and method. The system is characterized in that one end of a double-sleeve gas conveying pipe extends out of an ignition hole, the outer pipe of the end is connected with an oxygen supply device and / or an air supply device, and the inner pipe of the end is connected with a spontaneous-combustion-agent conveying device and a combustion-supporting-agent conveying device; an ignition device comprises an outer sleeve, an inner sleeve, a nozzle seat and at least three ignition nozzles, the outer sleeve and the inner sleeve are respectively connected with the outer pipe and the inner pipe of the double-sleeve gas conveying pipe, and the lower portion of the inner sleeve is fixedly connected with the nozzle seat; the circumferential direction of the inner sleeve is provided with threaded through holes which are arranged in an equal-distance manner and are adaptive to the ignition nozzles in number and position, and one end of each ignition nozzle is mounted at the corresponding threaded through hole; a corresponding hole is formed in a position, corresponding to the position of the other end of each ignition nozzle, of the outer sleeve, and a gap is formed between each hole and the end face of the corresponding ignition nozzle; the bottom of the outer sleeve is sealed, and metallic sodium wrapped by paraffin is placed at the bottom of the outer sleeve; the top of the ignition hole is selectively sealed by a pipeline, and the pipeline is provided with a pressure gauge and a valve.

Description

technical field [0001] The invention relates to the technical field of underground coal gasification technology, in particular to an underground coal gasification deep hole ignition system and an ignition method. Background technique [0002] Underground coal gasification is the process of controlled combustion of underground coal to generate combustible gas through pyrolysis and chemical action of coal. To realize underground coal gasification, the coal in the underground coal seam must first be ignited. There are two main types of underground coal gasification technology: mine-type underground gasification and drilling-type underground gasification. [0003] Mine-type underground gasification is to manually develop tunnels and arrange underground gasifiers in the coal seam, so that people can go down into the coal seam and make sufficient preparations for gasification in the coal seam. The drilling type gasification is drilled into the coal seam, and then ignites the coal...

AI Technical Summary

Problems solved by technology

The disadvantages of this method are: (1) when the borehole is deep, the coke may burn out and extinguish during the falling process; (2) when there is water at the bottom of the borehole, the hot coke will be extinguished when it encounters water; It may block the drilling, affect the next ignition work, increase the resistance of the gasification process, and then increase the operating cost. Therefore, coke ignition sometimes cannot ignite the coal seam, and the risk is greater

Electric ignition has the advantages of simplicity and safety, but sometimes the igniter cannot be in good contact with the coal seam, and the ignition time is longer in the presence of groundwater

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