Water catchment control method 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 invention relates to the field of coal mining, in particular to a water catchment control method in an underground coal gasification process and an underground coal gasification method. Background technique [0002] As a rising coal gasification technology, underground coal gasification has attracted extensive attention due to its economy, environmental protection and high efficiency. However, the poor controllability of the underground coal gasification process, the greater influence of water in the coal seam and other interfering factors directly lead to the poor controllability of the underground gasification process. Unstable traffic and other issues. [0003] Since the roof of the underground coal seam is generally in contact with the aquifer, under the action of water pressure, the water head of the coal seam will change with the change of the air pressure in the gasifier. When the air pressure in the underground gasifier decreases, the hei...

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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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