A method for disaster prevention and gas production by filling mine goaf with plant organic materials

Abstract

The present invention provides a method for disaster prevention and gas production by filling the goaf of a mine with plant organic materials. The method collects coal gangue from the mine and surplus straw and branches from the agricultural, forestry and pastoral areas adjacent to the mine, crushes and screens them respectively, adds adhesives and special anaerobic bacteria capsules, and presses them into spherical plant organic materials with certain strength, flame retardancy and water resistance through mechanical processing after full mixing. The materials are then filled in the goaf of the mining face to control air leakage in the goaf and slow down the subsidence of the ground surface. When the mining of the working face is completed, the special anaerobic bacteria capsules are degraded and broken to release the domesticated inoculum, decompose the plant fibers in the plant organic materials, produce methane and form gas reservoirs. The gas reservoir is evaluated by using the ground mine monitoring and control system and the underground manual detection, and the ground extraction is carried out after reaching the standard. The method of the present invention is simple to operate and has great significance for preventing disasters in the goaf, controlling surface collapse and utilizing abandoned mines.

Description

Technical Field

[0001] The invention belongs to the technical field of coal mine safety and low-carbon energy storage, and specifically relates to a method for disaster prevention and gas production by filling a mine goaf with plant organic materials. Background Art

[0002] Coal mining conditions in my country are extremely complex, and accidents such as mine fires, gas, and roof collapse occur from time to time. At present, most mining faces use the caving method to manage the roof, and spontaneous combustion in the goaf, ground subsidence, and collapse disasters occur from time to time. In addition, my country is a large agricultural country, and the surface contains a large amount of surplus plant matter, such as a large amount of straw, branches, and excess grass after grain harvest. The burning and disorderly oxidation of surplus plant matter on the surface will produce a large amount of CO 2 , causing air pollution and waste of resources. Therefore, there is an urgent need for a method to effectively process and utilize the surplus plant organic matter resources on the surface to reduce the pollution of the plant body to the atmosphere and develop valuable materials for mines.

[0003] Therefore, in order to solve the problems existing in the existing preparation process, the present invention provides a method for disaster prevention and gas production by filling the goaf of a mine with plant organic materials. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for disaster prevention and gas production by filling the goaf of a mine with plant organic materials in view of the deficiencies of the above-mentioned prior art. The method collects coal gangue from the mine and surplus straw and branches and other plant bodies in the agricultural, forestry and pastoral areas adjacent to the mining area, crushes and screens them respectively, adds adhesives and special anaerobic bacteria capsules, and presses them into spherical plant organic materials with certain strength, flame retardancy and water resistance through mechanical processing after full mixing. The materials are then filled in the goaf of the mining face to control air leakage in the goaf and slow down the subsidence of the ground surface. When the mining face is completed, the special anaerobic bacteria capsules are degraded and broken to release the domesticated inoculum, decompose the plant fibers in the plant organic materials, produce methane and form gas reservoirs. The ground mine monitoring and control system and the underground manual detection and evaluation of the gas reservoir are used, and ground extraction is carried out after the standards are met. The method of the present invention is simple to operate and has great significance for preventing disasters in goaf areas, controlling surface collapse and utilizing abandoned mines.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for disaster prevention and gas production by filling the goaf of a mine with plant organic materials, the preparation method comprising the following steps:

[0006] S1. Dry the gangue at a constant temperature until the quality is stable and unchanged, and then crush the dried gangue into gangue particles; air the straw and branches until the quality is stable and unchanged, and then cut the dried straw and branches into plant fragments;

[0007] S2, uniformly mixing the special anaerobic bacteria capsules, the adhesive, the gangue particles and the plant fragments obtained in S1 to obtain a mixed dry material; uniformly mixing the mixed dry material and water to obtain a mixed slurry, and mechanically pressing the mixed slurry to obtain a preliminary spherical plant organic material; and then curing the preliminary spherical plant organic material to obtain a spherical plant organic material;

[0008] S3. Transport the spherical plant organic material obtained in S2 to the underground working surface and place it at a predetermined position in the goaf.

[0009] Preferably, the temperature of the constant temperature drying in S1 is 100° C., the particle size of the gangue particles is 1-3 mm, and the size of the plant fragments is 3-5 mm.

[0010] Preferably, the mass ratio of the gangue particles, plant fragments, binder and special anaerobic bacteria capsules in S2 is 7:3:2:2, the binder is P.O52.5 silicate cement, the mass ratio of the mixed dry material and water is 3:1, the diameter of the preliminary spherical plant organic material is 8-10cm, the curing is carried out at a temperature of 20°C, and the curing time is 28 days.

[0011] Preferably, the special anaerobic bacteria capsule in S2 is divided into a capsule shell and an inoculum after acclimation, the capsule shell is formed by mixing polyethylene, polylactic acid, sodium stearate and plasticizer in a mass ratio of 12:6:1:1, and the preparation method of the inoculum after acclimation is: the inoculum is taken from a sewage treatment plant, and the inoculum is cultured and acclimated in a constant temperature incubator at a temperature of 37°C until the original organic matter in the inoculum is consumed; the microbial components in the inoculum after acclimation include cellulose degrading bacteria, hydrogen-producing and acetogenic bacteria, methanogenic bacteria and methanosarcina, the total solid content of the inoculum after acclimation is 1.70±0.10%, the volatile solid content is 0.60±0.08%, the relative abundance of cellulose degrading bacteria is 25%-30%, the relative abundance of hydrogen-producing and acetogenic bacteria is 15%-18%, the relative abundance of methanogenic bacteria is 3%-5%, and the relative abundance of methanogenic bacteria is 3%-5%.

[0012] Preferably, the capsule shell consists of two half shells, the upper half shell is 7.2 mm long, 0.1 mm thick, 5.3 mm outer diameter at the mouth, and 5.1 mm inner diameter at the mouth; the lower half shell is 12.2 mm long, 0.1 mm thick, and 5 mm outer diameter at the mouth. The two half shells are assembled by snapping together, and the capsule shell after snapping together is 14 mm long and 5.3 mm in diameter.

[0013] Compared with the prior art, the present invention has the following advantages:

[0014] 1. The present invention utilizes coal gangue and surplus plant bodies such as straw, branches and grass to make spherical plant organic materials, and uses them for filling mine goafs. On the one hand, it can effectively utilize mine solid waste and surplus plant bodies on the surface, reduce the land occupation and pollution of coal gangue, and reduce environmental pollution and resource waste caused by burning and disorderly oxidation of plant bodies. On the other hand, it can effectively control air leakage, spontaneous combustion and ground subsidence in goafs.

[0015] 2. In the process of making spherical plant organic materials, the present invention adds special anaerobic bacteria capsules, which can be degraded and broken according to the working face recovery and closure time to release the domesticated inoculum solution. The microbial shells in the domesticated inoculum solution decompose plant fiber to produce methane, forming a methane gas reservoir in the closed goaf. The methane gas reservoir can be monitored and evaluated online and manually. The qualified methane gas reservoir resources can be developed and utilized on a large scale by ground drilling, realizing the regeneration and storage of abandoned mine resources and reasonable development.

[0016] 3. The present invention controls the degradation and rupture time of anaerobic bacteria capsules by adjusting the ratio of polyethylene and polylactic acid. The inoculum in the special anaerobic bacteria capsule is taken from the sewage treatment plant; after the tamed inoculum is released, it comes into direct contact with plant organic materials, and can fully ferment and decompose plant fiber materials to produce methane gas. The concentration of methane gas reservoirs generally needs to reach more than 6%. When evaluating the reserves of methane gas reservoirs, one mining area is generally used as a unit. The extraction process of methane gas reservoirs generally adopts ground L-type drilling, which can penetrate the isolation coal pillars of each goaf area to achieve large-scale extraction of methane gas reservoirs.

[0017] The present invention is further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the composition of the spherical plant organic material in the present invention.

[0019] Figure 2 It is a cross-sectional schematic diagram of the filling process of the spherical plant organic material in the present invention.

[0020] Figure 3 It is a schematic diagram of the methane gas reservoir monitoring and extraction method in the goaf area of ​​the working face in the present invention.

[0021] Description of reference numerals:

[0022] 1—special anaerobic bacteria capsule; 2—coal gangue particles; 3—plant body fragments; 4—binder; 5—filling hydraulic support; 6—rear-mounted scraper conveyor; 7—unloading hole; 8—goaf; 9—pushing and compacting mechanism; 10—solid coal; 11—coal mining machine; 12—spherical plant organic material; 13—isolation coal pillar; 14—methane gas; 15—enclosed wall; 16—ground L-shaped drilling; 17—mine monitoring and surveillance system; 18—exhaust main pipe; 19—exhaust branch pipe. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Example 1

[0025] In this embodiment, the method for disaster prevention and gas production by filling the goaf of a mine with plant organic materials comprises the following steps:

[0026] S1. Dry the gangue at a constant temperature of 100° C. until the quality is stable and unchanged, then crush the dried gangue into gangue particles with a particle size range of 1-3 mm using an impact crusher (model PF-1007), air the straw and branches until the surface is dry and the quality is stable and unchanged, use a baler (model 9YFZ-2.2) to pack the dried straw and branches into a cylindrical shape with a diameter of 150 cm and a height of 80 cm, and then use a straw crusher (model JL800) to crush them to obtain plant fragments with a size range of 3-5 mm;

[0027] S2, the gangue particles obtained in S1, the plant fragments obtained in S1, the special anaerobic bacteria capsules and the adhesive are mixed in a mass ratio of 7:3:2:2 to obtain a mixed dry material; then the mixed dry material and water are mixed in a mass ratio of 3:1 to form a mixed slurry; the mixed slurry is pressed into a spherical mold to obtain a preliminary spherical plant organic material with a diameter of 8-10 cm; and the preliminary spherical plant organic material is cured at a temperature of 20°C for 28 days to obtain a spherical plant organic material with a uniaxial compressive strength of more than 5MPa (such as Figure 1 shown);

[0028] The special anaerobic bacteria capsule is divided into a capsule shell and an inoculum after acclimation. The capsule shell is made of polyethylene, polylactic acid, sodium stearate and plasticizer mixed in a mass ratio of 12:6:1:1. The capsule shell is composed of two half shells, the upper half shell is 7.2 mm long, the wall thickness is 0.1 mm, the outer diameter of the mouth is 5.3 mm, and the inner diameter of the mouth is 5.1 mm; the lower half shell is 12.2 mm long, the wall thickness is 0.1 mm, and the outer diameter of the mouth is 5 mm. The two half shells are assembled by buckling. The length of the capsule shell after buckling is 14 mm and the diameter is 5.3 mm. The preparation method of the inoculum after acclimation is as follows: The biological components include cellulose-degrading bacteria, hydrogen-producing and acetogenic bacteria, methanobacterium and methanosarcina. The total solid content of the domesticated inoculum is 1.70±0.10%, the volatile solid content is 0.60±0.08%, the relative abundance of cellulose-degrading bacteria is 25%-30%, the relative abundance of hydrogen-producing and acetogenic bacteria is 15%-18%, the relative abundance of methanobacterium is 3%-5%, and the relative abundance of methanosarcina is 3%-5%; the mass ratio of the coal gangue particles, plant fragments, binder and special anaerobic bacteria capsule is 7:3:2:2, and the binder is P.O52.5 silicate cement;

[0029] S3. Transport the spherical plant organic material obtained in S2 to the underground working surface and place it at a predetermined position in the goaf.

[0030] When the working face starts to be mined, the prepared bagged spherical plant organic materials 12 are transported to the working face by the mine transportation system to prepare for filling the goaf 8. The specific operation method is: the coal mining machine 11 cuts the solid coal 10 at a 0.8m advance. After cutting the coal for a certain distance, the corresponding filling hydraulic support 5 (model ZC5160 / 30 / 50) is moved forward by a step distance, and the spherical plant organic materials 12 are placed on the rear scraper conveyor 6 near the top of the goaf 8, and the rear scraper conveyor 6 is started to start the filling work. The filling direction is from the tail of the rear scraper conveyor 6 to the head direction. The first discharge hole 7 at the tail is opened, and the spherical plant organic material 12 is filled into the corresponding goaf 8. After the goaf 8 corresponding to the discharge hole 7 is filled to a certain height, the discharge hole 7 is closed, and the pushing and compacting mechanism 9 is started to compact the spherical plant organic material 12 filled into the goaf 8 until the goaf 8 corresponding to the discharge hole 7 is filled. As the coal cutting proceeds, the above process is repeated to carry out the next stage of filling until the entire goaf 8 is filled;

[0031] After the working face is mined and the closed wall 15 is constructed, after the specified time has passed, the specially made anaerobic bacteria capsules 1 in the spherical plant organic material 12 are degraded and ruptured to release the domesticated inoculum, and the domesticated inoculum contacts the plant fragments 3 to start an anaerobic reaction. In the initial stage of the reaction, the cellulose-degrading bacteria in the domesticated inoculum hydrolyze the cellulose and hemicellulose in the plant fragments 3 to produce cellobiose, and the hydrogen-producing and acetic acid-producing bacteria further hydrolyze the cellobiose to produce formic acid, acetic acid, and H 2 and CO 2 In the middle of the reaction, the formic acid, acetic acid, and H 2 and CO 2 The colonies of Methanobacterium and Methanosarcina in the inoculum after acclimation were expanded; in the later stage of the reaction, Methanobacterium used H 2 and CO 2 Generate methane gas 14, Methanosarcina utilizes formic acid and acetic acid to generate methane gas 14. Coal gangue particles 2 are waste materials, and their function is to fill and support the goaf 8, and the binder 4 is used to bind the coal gangue particles 2, plant fragments 3 and spherical plant organic materials 12 together.

[0032] As time goes by, the methane gas 14 produced by the spherical plant organic material 12 fills the goaf 8, gradually forming a methane gas reservoir. The concentration of methane gas 14 is monitored in real time by the mine monitoring system 17. The methane gas 14 sample extracted from the filled goaf 8 is collected by the extraction branch pipe 19 into the extraction main pipe 18, and the extraction position is automatically controlled by the valve on the extraction branch pipe 19. At the same time, the methane gas 14 sample in the closed and filled goaf 8 can be manually extracted at regular intervals using the observation hole reserved on the closed wall 15, and the change of the methane gas 14 concentration can be observed on site, and compared and verified with the monitoring data of the mine monitoring system 17. When the concentration of methane gas 14 in each filled goaf 8 reaches more than 6%, in order to ensure the scale of the methane gas reservoir, a ground L-shaped drilling well 16 can be arranged to penetrate the isolation coal pillar 13 in each goaf 8, and implement joint extraction of multiple filled goafs 8.

[0033] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent change made to the above embodiment according to the technical essence of the invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for disaster prevention and gas production by filling the goaf of a mine with plant organic materials, characterized in that: The method comprises the following steps: S1. Dry the gangue at a constant temperature until the quality is stable and unchanged, and then crush the dried gangue into gangue particles; air the straw and branches until the quality is stable and unchanged, and then cut the dried straw and branches into plant fragments; S2, uniformly mixing the special anaerobic bacteria capsules, the adhesive, the gangue particles and the plant fragments obtained in S1 to obtain a mixed dry material; uniformly mixing the mixed dry material and water to obtain a mixed slurry, and mechanically pressing the mixed slurry to obtain a preliminary spherical plant organic material; and then curing the preliminary spherical plant organic material to obtain a spherical plant organic material; S3, transporting the spherical plant organic material obtained in S2 to the underground working surface and placing it at a predetermined position in the goaf; The mass ratio of the gangue particles, plant fragments, binder and special anaerobic bacteria capsules in S2 is 7:3:2:2, the binder is P.O52.5 silicate cement, the mass ratio of the mixed dry material and water is 3:1, the diameter of the preliminary spherical plant organic material is 8-10cm, the curing is carried out at a temperature of 20°C, and the curing time is 28 days; The special anaerobic bacteria capsule described in S2 is divided into a capsule shell and an inoculum solution after acclimation, the capsule shell is mixed with polyethylene, polylactic acid, sodium stearate and plasticizer in a mass ratio of 12:6:1:1, and the preparation method of the inoculum solution after acclimation is as follows: the inoculum solution is taken from a sewage treatment plant, and the inoculum solution is cultured and acclimated in a constant temperature incubator at a temperature of 37°C until the original organic matter in the inoculum solution is consumed; the microbial components in the inoculum solution after acclimation include cellulose degrading bacteria, hydrogen-producing and acetogenic bacteria, methanobacterium and methanosarcina, the total solid content of the inoculum solution after acclimation is 1.70±0.10%, the volatile solid content is 0.60±0.08%, the relative abundance of cellulose degrading bacteria is 25%-30%, the relative abundance of hydrogen-producing and acetogenic bacteria is 15%-18%, the relative abundance of methanobacterium is 3%-5%, and the relative abundance of methanosarcina is 3%-5%.

2. A method for disaster prevention and gas production by filling mine goaf with plant organic materials according to claim 1, characterized in that: The temperature of the constant temperature drying in S1 is 100° C., the particle size of the coal gangue particles is 1-3 mm, and the size of the plant fragments is 3-5 mm.

3. The method for disaster prevention and gas production by filling the goaf of a mine with plant organic materials according to claim 1, characterized in that: The capsule shell consists of two half shells, the upper half shell is 7.2 mm long, the wall thickness is 0.1 mm, the outer diameter of the mouth is 5.3 mm, and the inner diameter of the mouth is 5.1 mm; the lower half shell is 12.2 mm long, the wall thickness is 0.1 mm, and the outer diameter of the mouth is 5 mm. The two half shells are assembled by snapping together. After snapping together, the capsule shell is 14 mm long and 5.3 mm in diameter.

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