CN-116335764-B - Construction method of coal seam gasification closed space

Abstract

The invention discloses a construction method of a coal seam gasification airtight space, which comprises the following steps of S1, before stoping a working face, building a cement wall on the outer surface of a non-coal face along the directions of a cutting hole, a return air lane and a transport lane, S2, driving a connecting lane penetrating through the working face on one side of the working face close to the development lane, building the cement wall on the outer surface of the working face on one side close to the development lane along the direction of the connecting lane, S3, reserving top coal with preset thickness in the stoping process of the working face, S4, after stoping of the working face is finished, plugging the cement walls at two ends of the connecting lane, grouting a separation layer above a goaf to form an artificial grouting layer, and arranging microorganism nutrient solution drilling holes and gas test drilling holes on the corresponding ground surface right above the goaf to realize in-situ microorganism gasification exploitation of coal resources.

Inventors

• ZHU LIU
• YAO QIANGLING
• Shang Xiaobei
• Diao Wangjie

Assignees

• 中国矿业大学

Dates

Publication Date

20260508

Application Date

20230403

Claims (1)

1. 1. The construction method of the coal seam gasification airtight space is characterized by comprising the following steps: S1, before stoping of a working face (6), building a cement wall (4) on the outer surface of a non-coal face along the directions of a cutting hole (7), a return air lane (5) and a transport lane (8), after the cement wall (4) is built, spraying waterproof materials on the surface of the cement wall, wherein two ends of the cement wall in the direction of the cutting hole (7) are respectively connected with the cement wall (4) in the directions of the return air lane (5) and the transport lane (8); S2, driving a connecting roadway (2) penetrating through the working surface on one side of the working surface (6) close to the development roadway (1), and building a cement wall (4) on the outer surface of the working surface (6) on one side close to the development roadway (1) along the direction of the connecting roadway (2); s3, reserving top coal with preset thickness in the stoping process of the working face (6); S4, after stoping of the working face (6) is finished, blocking cement walls (4) at two ends of the connecting roadway (2), grouting a separation layer belt (12) above a goaf (14) to form an artificial grouting layer (11), arranging microorganism nutrient solution drilling holes (9) and gas testing drilling holes (10) on the ground surface corresponding to the goaf (14), wherein the blocking of the cement walls (4) at two ends of the connecting roadway (2) comprises the steps that the cement walls (4) at two ends of the connecting roadway (2) extend towards two ends respectively and are connected with the cement walls (4) in the directions of the air return roadway (5) and the conveying roadway (8) respectively to form a closed loop.

Description

Construction method of coal seam gasification closed space Technical Field The invention relates to the field of in-situ gasification of coal microorganisms, in particular to a construction method of a coal seam gasification closed space. Background Coal is still the main energy of our country, and at present, coal exploitation in our country is mainly well engineering exploitation, and when well engineering exploitation, it is impossible to exploit all coal seams, especially some thick coal seams. The limitations of coal mining technology result in significant loss of coal resources. The existing experiments show that microorganisms can convert coal into gas through anaerobic fermentation, so that students propose an in-situ microorganism gasification exploitation method of coal resources. The method can further recover the coal resources wasted in the underground mining, can realize clean utilization of the coal resources and increase the mining of coal bed gas. The method is to inject the strain and nutrient solution of gasified coal into the coal bed, and perform anaerobic fermentation in the coal bed. When the method is used on site, the method is limited by site environment and cannot be realized, because anaerobic fermentation strains are generally strict anaerobic bacteria, the biological activity is reduced rapidly once the anaerobic fermentation strains are contacted with oxygen, after the shallow-buried thick coal seam is mined, the overlying strata fracture extends to the ground, the ground surface is communicated with a goaf, the growth of methanogenic bacteria is not facilitated, when the goaf is filled with nutrient solution, the nutrient solution is diffused all around due to the development of the goaf fracture, the loss is caused, and the gas generated by gasification cannot be gathered and extracted if the gas is not blocked. In situ bio-gasification of coal can be achieved if an enclosed space is constructed downhole manually. How to overcome the existing environment and realize the in-situ microbial gasification exploitation of coal resources is a problem to be solved in the field, and has important significance for exploitation of coal resources in China. Disclosure of Invention Aiming at the problem that in-situ microbial gasification exploitation of coal is difficult to implement due to the influence of ready environment, the invention provides a construction method of a coal seam gasification closed space, and the in-situ biological gasification exploitation of coal resources left in a goaf is realized by manually creating a downhole closed space. The construction method of the coal seam gasification airtight space comprises the following steps: S1, before stoping of a working face, building a cement wall on the outer surface of a non-coal face along the directions of a cutting hole, a return air lane and a transport lane; S2, tunneling a connecting roadway penetrating through the working face on one side of the working face, which is close to the development roadway, and building a cement wall on the outer surface of the working face on one side, which is close to the development roadway, along the direction of the connecting roadway; s3, reserving top coal with preset thickness in the stoping process of the working face; And S4, after stoping of the working face is finished, blocking cement walls at two ends of the linkage roadway, grouting a separation layer belt above the goaf to form an artificial grouting layer, and arranging microorganism nutrient solution drilling holes and gas testing drilling holes on the surface corresponding to the top of the goaf. Preferably, in the step S1 and the step S2, the surface of the cement wall is sprayed with a waterproof material after the cement wall is built. Preferably, in the step S1, two ends of the cement wall in the cutting direction are respectively connected with the cement walls in the return air lane and the transport lane directions. Preferably, in the step S4, the plugging of the cement walls at two ends of the connecting roadway includes that the cement walls at two ends of the connecting roadway extend towards two ends respectively and are connected with the cement walls in the directions of the return roadway and the transport roadway respectively to form a closed loop. Compared with the prior art, the method has the advantages that after stoping of the working face, a coal mine underground coal microorganism gasification space is constructed in the goaf, firstly, the goaf can be always plugged by the cement wall to prevent harmful gas from polluting other working faces, secondly, the cement wall is constructed in the roadway and belongs to secondary utilization of the roadway, the utilization rate of the roadway is improved, thirdly, a fermentation space of coal in the shallow coal seam goaf is formed by utilizing the cement wall and rock stratum grouting isolation, so that in-situ biological gasification exploitation of coa