Method for controlling water collection quantity in underground coal gasification process and underground coal gasification method

Abstract

The invention provides a method for controlling the water collection quantity in an underground coal gasification process. The method comprises the following steps of: monitoring the actual water collection quantity in the gasification process and the gas pressure in an underground gasification furnace, comparing the actual water collection quantity with a water quantity required by the gasification process, and regulating the gas pressure in the underground gasification furnace so as to change the actual water collection quantity to ensure that the difference value between the actual water collection quantity and the water quantity required by the gasification process is kept in an allowable error range; when the coal consumption in a gasification region reaches a certain proportion of the coal reserve of the region, moving a gas filling pipe backward according to a set position distance so as to change the position of a gasification surface to perform gasification of a next-section coal seam. The invention also provides an underground coal gasification method. According to the underground coal gasification method and the water collection quantity control method, by virtue of the method of regulating the gas pressure in the underground gasification furnace and injecting water through a gas inlet passage in the gasification process, the actual water collection quantity of the gasification surface of the underground gasification furnace is kept stable, and stable execution of the gasification process is facilitated.

Description

Technical field [0001] The present invention involves the field of coal mining, and specially involves a method of water volume control in the process of underground gasification of coal and an underground gasification method of coal. Background technique [0002] As a kind of gasification technology that is emerging, coal underground gas has received widespread attention due to its economy, environmental protection and efficiency.However, a variety of interference factors such as poor controllability in coal underground gasification and the greater impact of water in the coal seam directly lead to poor controllability of the underground gasification process.Unstable problems such as traffic. [0003] Because the ground coal seam top plate is generally connected to the water -containing layer, under the influence of water pressure, the coal selemers' water head will change with the changes in the air pressure in the furnace of the furnace.The height of the water head in the local...

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Problems solved by technology

[0004] In the existing technology, the treatment method of coal seam catchment water in the underground gasification process is relatively simple. The common method is to use the pump to directly extract the water in the roof aquifer or the water in the burnout area from the drilling.

However, the controllability of this method is poor, and due to the continuous expansion of the underground gasifier, the change of the water accumulation point in the underground gasifier, and the different water seepage rates of the aquifer, it cannot be achieved during the gasification process of the gasifier. Stable and effective control of water catchment in coal seam

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