A method for cleaning coal powder in the sealing section of gas drainage drilling

Abstract

The invention discloses a method for cleaning the pulverized coal in the sealing section of the borehole for gas drainage. The underground compressed air system of the coal mine is used to connect the underground compressed air system with the gas injection pipe, so that the gas injection pipe can better blow up the coal powder in the sealed area ;The air inlet of the suction pipe is matched with the nozzle of the gas injection pipe, which can inhale the blown coal powder to the maximum extent. The pulverized coal enters the pulverized coal storage tank through the suction pipe, and the fine water mist can quickly contact and wrap the pulverized coal On the surface of the pulverized coal, under the action of the liquid nitrogen mist, the fine water mist on the surface of the pulverized coal condenses rapidly, speeding up its descent speed, so that the pulverized coal quickly settles to the bottom of the pulverized coal storage tank; Move inside the borehole to clean up the coal powder at various positions in the borehole. Therefore, the present invention has the advantages of good coal dust cleaning effect and high efficiency. At the same time, the dust will not affect the working environment of the roadway during the cleaning process, and it can reduce the air leakage after the drilling is sealed and improve the gas drainage effect. It has a wide range of practical applications. sex.

Description

technical field [0001] The invention relates to a method for cleaning residual coal powder in a borehole, in particular to a method for cleaning coal powder in the sealing section of a gas drainage borehole. Background technique [0002] The sealing quality of boreholes for underground gas drainage in coal mines is one of the important factors determining the effect of drilling gas extraction. Field investigations have found that a large amount of coal powder remains in the sealing section of gas drainage drilling, and the possible consequences are as follows Aspects: ①The pulverized coal in the borehole hinders the normal insertion of the sealing device. When there is too much pulverized coal, the sealing device cannot be inserted into the designated position; The space inside and outside the borehole forms an air guide channel, which greatly reduces the sealing quality of the borehole. The existing methods for cleaning the drilled coal powder mainly include high-pressure ...

AI Technical Summary

Problems solved by technology

High-pressure water injection can solve the coal dust cleaning of non-near-horizontal drilling holes in hard coal seams, but for soft coal seams, under the action of high-pressure water, there will be negative effects, that is, the soft coal bodies around the drilling holes will collapse when they encounter water, resulting in drilling failure

The method of high-pressure air injection has the following problems when cleaning the drilled coal powder: ①The coal powder at the position of the high-pressure air outlet is blown up and settles nearby, eventually forming a wavy line of coal powder accumulation, the farther away from the drill hole, The worse the cleaning effect of coal dust is; ②When the high-pressure air is injected, the fine coal dust will flow out of the drill hole, forming dust in the roadway, polluting the working environment in the roadway, and seriously endangering the health of coal miners

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