Method for filling underground spaces and system for filling underground spaces

Abstract

The invention provides a method for filling underground spaces, which comprises steps of extracting sewage from an underground gasification cavity to be delivered into a settling basin to be purified; mixing the purified water with crushed solid pulping raw materials to form pulp; and filling the pulp into the underground spaces and drying the pulp. The invention further provides a system for filling underground spaces, which comprises a water pump, a settling basin, a water injection system and a pulp injection device, the water pump extracts sewage from an underground gasification cavity, the settling basin purifies the sewage, and is provided with a purified water outlet and a sewage inlet, purified water flows out via the purified water outlet, the sewage inlet is communicated with an outlet of the water pump, the water injection system is provided with a water delivery pipe, the water delivery pipe is provided with a water outlet and a water inlet communicated with the purified water outlet of the settling basin, the pulp injection device is provided with a material supply opening, a water supply opening and a delivery device, crushed solid pulping raw materials enter the material supply opening, the water supply opening is communicated with the water outlet, and pulp mixed by the solid pulping raw materials and the purified water is delivered to an underground space by the delivery device. On the one hand, risks of pollution of underground water are reduced, and on the other hand, risks that soil on the earth surface is polluted are reduced.

Description

technical field [0001] The invention relates to a method for filling an underground space and a system for filling the underground space. Background technique [0002] During the underground coal gasification process, with the continuous development of the combustion face, a large area of ​​coal seam burn-out area will be formed underground. After the gasifier is running or closed, the heat in the burn-out area will continue to heat the surrounding unreacted coal seam, thereby The dry distillation reaction of the coal seam produces a large amount of tar and organic matter. These organic matter are brought into the burnout zone through the seepage around the coal seam to form underground sewage, which then affects the underground aquifer. Long-term infiltration will also cause the water in the aquifer to be affected Pollution; the expansion of the burn-up area will also cause the support strength of the upper rock roof to decrease, and in the long run it will also cause the r...

AI Technical Summary

Problems solved by technology

However, this in-situ recovery system can only reduce the volatile organic compounds in the sewage, and there is no further treatment for other pollutants, and the existence of negative pressure in the burn-out zone will cause the upper layer of water to continuously leak into the burn-out zone, and the pollutants will also Migrate with the flow of water, causing further contamination of groundwater

[0006] Prior art 3: US5287926 introduces filling sand, slag, coal ash and other wastes into the burn-out area to avoid problems such as roof caving in the burn-out area, but the filling of solid pulping raw materials is suitable for steeply inclined coal seams, and the solid Minerals cannot fill the burn-off area through self-settling, resulting in congestion near the filler pipe, uneven distribution in the burn-off area, and no strong support for the roof. Therefore, this technology cannot comprehensively solve the problem of roof caving in the underground burn-off area. question

[0007] Prior art 4: CN101021161A introduces a goaf backfilling method used in mining systems. It mainly drills wells into the roadway, fills the roadway with mixed slurry through the conveying pipeline, and makes the slurry evenly distributed through vibration. To achieve the purpose of supporting the roof, but this technology needs to introduce a large number of ground water sources to make the slurry into a liquid form, which not only causes a lot of waste of ground drinking water, but also introduces additional water into the underground gasification system, affecting the gasification process carry out

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