A coal mine backfilling mining co-processing carbon dioxide sequestration system and method

Abstract

This invention proposes a coal mine backfilling mining and carbon dioxide sequestration system and method. It isolates mining-backfilling-solidification units within the longwall face using dense artificial dams. Within each unit, a Wangevelli shortwall face is arranged, and a continuous miner is used to complete the coal mining process. Telescopic backfilling pipelines are laid to complete the backfilling process, and carbon injection pipelines are buried for subsequent carbon sequestration. This invention utilizes the continuous miner, telescopic backfilling pipelines, and carbon injection pipelines to perform backfilling in different roadways simultaneously with continuous coal mining. Carbon injection pipelines are buried concurrently with backfilling. After the mining and backfilling processes are completed in all mining-backfilling-solidification units across the entire mining area, carbon injection is implemented to achieve underground CO₂ sequestration, forming an integrated coal mine mining-backfilling-solidification system and method. This invention achieves pillarless mining, increasing coal recovery rate, processing large quantities of coal gangue, and fully utilizing the space of the coal mine goaf, while permanently sequestering CO₂ greenhouse gases, providing a new method for carbon sequestration technology.

Description

Technical Field

[0001] This invention relates to the field of coal mining technology, specifically to a coal mine backfilling mining co-operated carbon dioxide sequestration system and method, which is particularly suitable for the carbon sequestration function utilization of goaf areas after coal mining. Background Technology

[0002] my country's coal industry is large in scale and heavily polluting, making it a key sector for green and low-carbon reforms. Under the strategic guidance of my country's "dual-carbon goals," the coal industry is facing opportunities for high-quality, high-tech development and is moving towards carbon neutrality. Within the existing coal utilization technology system, developing underground CO2 storage technologies tailored to local conditions, and tackling key challenges in carbon sequestration, has become one of the key approaches for the coal industry to achieve its "dual-carbon goals."

[0003] Current coal backfilling mining technology has achieved goals such as the treatment of bulk gangue and other solid wastes and precise control of surface subsidence. It is now focusing on improving the functionality of backfilling materials and optimizing backfilling mining systems. Based on the current strategic guiding principle of "dual carbon targets," utilizing backfilling materials for carbon sequestration is a multi-beneficial engineering research approach.

[0004] Based on this, the present invention provides an integrated mining, filling, and carbon sequestration system and method for coal mines, provides a production system layout suitable for geological CO2 sequestration in coal mine goaf areas, provides a filling mining-coordinated carbon dioxide sequestration system that completes coal mining, filling, and carbon sequestration processes underground, and provides a coal mine filling mining-coordinated carbon dioxide sequestration method and process based on this system. Summary of the Invention

[0005] To fully utilize the space in underground goaf areas, achieve high-value utilization of solid waste materials such as gangue, and safely and efficiently store CO2 in coal mines, this invention provides a coal mine backfilling mining co-coal carbon dioxide storage system and method, designs the layout method of backfilling and solidification units, and designs the backfilling mining co-coal carbon dioxide storage process, providing a new method for the safe and efficient storage of CO2 in the coal industry.

[0006] To achieve the above objectives, this invention isolates mining, filling, and consolidation units within the longwall working face using a dense artificial dam. Within each unit, a Wangevili shortwall working face is arranged, and a continuous miner is used to complete the coal mining process. Telescopic filling pipelines are laid to complete the filling process, and carbon injection pipelines are buried to subsequently complete the carbon fixation process. This invention utilizes the continuous miner, telescopic filling pipelines, and carbon injection pipelines to perform inter-road filling while continuously mining coal. Carbon injection pipelines are simultaneously buried during filling. After the mining and filling processes are completed within the mining, filling, and consolidation units of the entire mining area, the carbon injection process is implemented to achieve underground CO2 sequestration, forming an integrated coal mining, filling, and consolidation system and method.

[0007] A coal mine backfilling mining co-processing carbon dioxide sequestration system includes:

[0008] Mining-filling-solidification unit: Two parallel horizontal tunnels are mined to define the longwall working face. Then, within the longwall working face, multiple parallel unit tunnels are excavated perpendicular to the direction of the two horizontal tunnels. Adjacent unit tunnels form a closed mining-filling-solidification unit. Each mining-filling-solidification unit contains two centrally symmetrical Wangevli shortwall working faces.

[0009] Continuous mining machine: used to mine back the mining-filling-solidification unit to form the Wangevil shortwall working face. After the two Wangevil shortwall working faces are filled, the residual branch coal pillars on both sides of the two dense Wangevil shortwall working faces in each mining-filling-solidification unit are mined.

[0010] Telescopic filling pipeline: used for filling two Wangevili shortwall working faces in succession and filling the residual coal pillars in the goaf; the telescopic filling pipeline is laid through the corresponding horizontal roadway into the Wangevili shortwall working face; the telescopic filling pipeline can be filled and then removed.

[0011] Carbon injection pipeline: including carbon injection branch pipes and carbon injection main pipe. First, the carbon injection branch pipes are inserted into the coal pillars of each goaf residual branch roadway. Then, filling slurry is injected into each goaf residual branch roadway coal pillar through a telescopic filling pipeline. The spatial position of the carbon injection branch pipes is fixed based on the solidification characteristics of the filling slurry to complete the installation of the carbon injection branch pipes. The inner end of the carbon injection branch pipe is buried in the filling body formed by the filling slurry, and the outer end is left empty in its corresponding horizontal roadway. The carbon injection main pipe is suspended in the horizontal roadway and is connected to the outer ends of all the carbon injection branch pipes in its horizontal roadway.

[0012] A carbon dioxide sequestration method for a coal mine backfilling mining co-operated carbon dioxide sequestration system includes the following steps:

[0013] Step a: Excavate multiple parallel horizontal tunnels to delineate multiple longwall working faces; wherein, each pair of adjacent horizontal tunnels forms a longwall working face;

[0014] Step b: Excavate n unit roadways in parallel within the longwall working face, delineate mining, filling and solidification units, and determine the first mining, filling and solidification unit; the first mining, filling and solidification unit is set close to the track central roadway; the track central roadway is located behind the mining and solidification unit; each unit roadway is connected to two horizontal roadways based on each mining, filling and solidification unit.

[0015] Step c: Arrange two centrally symmetrical Wangevli shortwall working faces, one on the left and one on the right, within the first mining and backfilling unit;

[0016] Step d: Use a continuous miner to mine one Wangervili shortwall working face in the first mining and filling unit. Immediately after mining, use a telescopic filling pipeline for filling. After the filling slurry solidifies, mine and fill another Wangervili shortwall working face in the mining and filling unit.

[0017] Step e: The residual branch coal pillars on both sides of the two dense Wangevili shortwall working faces in the first mining and filling unit are mined back. After mining, carbon injection branch pipes are first inserted into the residual branch coal pillars of each mined-out branch, and then the telescopic filling pipeline is used to fill in the carbon injection branch pipes to complete the fixing and installation of the carbon injection branch pipes.

[0018] Step f: Fill the unit roadway located behind the first mining and backfilling unit to form an artificial dam;

[0019] Step g: Repeat steps c to f for the remaining adjacent mining, filling and solidification units within the same longwall working face, and finally fill the unit roadway adjacent to the last mining, filling and solidification unit in the longwall working face to form an artificial dam.

[0020] Step h: Install carbon injection main pipes in the horizontal tunnels on both sides of the first mining and backfilling unit, and collect all the carbon injection branch pipes in the horizontal tunnel.

[0021] Step i: Repeat steps a to h sequentially on different longwall working faces within the mining area;

[0022] Step j: Gather all the main carbon injection pipes in the mining area to the main carbon injection pipe and connect it to the surface carbon injection station. Inject liquid CO2 into the well from the surface carbon injection station to complete the carbon fixation process of all mining, filling and solidification units in the entire mining area.

[0023] Compared with the prior art, the advantages of the present invention are:

[0024] (1) While achieving coal pillar-free mining to significantly increase coal extraction rate, process large quantities of coal gangue and other wastes, and make full use of the space in the coal mine goaf, CO2 greenhouse gas is permanently sealed in the underground goaf, providing a new method for carbon sequestration technology and a new idea for achieving dual carbon goals in the coal industry.

[0025] (2) Compared with traditional backfilling mining methods, this invention is not only aimed at processing gangue and maintaining the overlying rock strata of the goaf, but also endows the backfilling material with carbon-fixing functional characteristics, which generates high added value benefits for the utilization of goaf and gangue materials.

[0026] (3) Compared with traditional geological CO2 storage methods, this invention has the advantages of controllable properties of key carbon sequestration materials and controllable carbon injection pipelines. By adjusting the properties of key carbon sequestration materials and the layout parameters of carbon injection pipelines, artificial control of carbon sequestration efficiency and carbon sequestration capacity can be achieved. Attached Figure Description

[0027] Figure 1 This is a plan view of the mining area layout of the present invention;

[0028] Figure 2 This is a flowchart of the sampling, filling, and consolidation unit operation of the present invention;

[0029] Figure 3 This is a schematic diagram of the layout of the mining, filling, and consolidation units in the mining area according to the present invention;

[0030] Figure 4 This is a schematic diagram of the well layout of the present invention;

[0031] Figure 5 This is a schematic diagram of an embodiment of the sampling and filling unit of the present invention.

[0032] Among them, 1-track central roadway; 2-transport central roadway; 3-track horizontal roadway; 4-transport horizontal roadway; 5-width D; 6-distance L; 7-unit roadway; 8-protected coal pillar boundary line; 9-mining-filling-solidification unit; 10-first mining-filling-solidification unit; 11-left Wangevili shortwall working face; 12-right Wangevili shortwall working face; 13-residual branch roadway coal pillar; 14-telescopic filling pipeline; 15-filling body; 16-carbon injection branch pipe; 17-carbon injection main pipe; 18-artificial dam; 19-carbon injection main pipe; 20-surface carbon injection station; 21-surface filling station; 22-vertical filling well; 23-shortwall branch roadway. Detailed Implementation

[0033] The present invention will now be described in more detail with reference to the accompanying drawings, which illustrate preferred embodiments of the invention. It should be understood that those skilled in the art can modify the invention described herein while still achieving its advantageous effects. Therefore, the following description should be understood as being of general knowledge to those skilled in the art and is not intended to limit the invention.

[0034] The present invention provides a coal mine backfilling mining and carbon dioxide sequestration system and method, which isolates mining, backfilling and sequestration units in the longwall working face through a dense artificial dam. In each mining, backfilling and sequestration unit, a Wangervili shortwall working face is arranged and a continuous miner is used to complete the coal mining process. Telescopic backfilling pipelines are laid to complete the backfilling process, and carbon injection pipelines are buried to complete the subsequent carbon sequestration process.

[0035] This invention utilizes a continuous mining machine, telescopic filling pipeline, and carbon injection pipeline to perform inter-road filling while continuously mining coal. During filling, carbon injection pipeline is simultaneously laid. After the mining and filling processes are completed in the mining-filling-solidification unit of the entire mining area, the carbon injection process is implemented to complete the underground sequestration of CO2, forming a coal mine filling mining-coordinated carbon dioxide sequestration system and method.

[0036] This invention enables coal extraction rate to be increased through pillarless mining, large-scale processing of coal gangue, and full utilization of coal mine goaf space, while permanently sequestering CO2 greenhouse gas. It provides a new method for carbon sequestration technology and features low carbon emissions, safety, and high utilization rate.

[0037] like Figure 1The mining area layout plan shown shows that the longwall working face first needs to arrange two horizontal roadways, namely, track roadway 3 and transport roadway 4, perpendicular to the track roadway 1 and transport roadway 2 of the mining area. The distance between track roadway 3 and transport roadway 4 is the width D (5) of the longwall working face. Then, n unit roadways 7 are excavated in parallel with the distance L (6) between the two horizontal roadways. Each unit roadway 7 is connected to track roadway 3 and transport roadway 4 and has a length of D (5). The first unit roadway is arranged along the boundary line 8 of the protective coal pillar of track roadway 1 and transport roadway 2 of the mining area. Two adjacent unit roadways 7 and track roadways 3 and transport roadways 4 on both sides jointly define a mining-filling-solidification unit 9. The mining-filling-solidification unit 9 defined by the first unit roadway 7 is the first mining-filling-solidification unit 10.

[0038] like Figure 2 The operation flow chart of the mining-filling-solidification unit 9 is shown in I-IV: The left Wangervili shortwall working face 11 and the right Wangervili shortwall working face 12 are arranged in reverse dense arrangement within the mining-filling-solidification unit 9. The length of the two Wangervili shortwall working faces is L (6), and the combined width of the two Wangervili shortwall working faces is D (5). The residual branch roadway coal pillars 13 (i.e., the Wangervili shortwall working face and the residual branch roadway coal pillars on both sides are formed simultaneously) are left on both sides of the two reverse dense (centrally symmetrical) Wangervili shortwall working faces. The Wangervili shortwall working face is mined by a continuous miner. After the mining of the left Wangervili shortwall working face 11 is completed, a telescopic filling pipeline 14 is immediately laid into the goaf of the left Wangervili shortwall working face 11 through the unit roadway 7, and filling slurry is injected into it. The telescopic filling pipeline 14 is withdrawn as it is filled and completely withdrawn after the filling of the left Wangervili shortwall working face 11 is completed. After the filling slurry in the goaf of the left Wanggeweili shortwall working face 11 has completely solidified into the filling body 15, the right Wanggeweili shortwall working face 12 is mined, and the following procedures are completed in sequence: laying the telescopic filling pipeline 14, injecting the filling slurry, and withdrawing the telescopic filling pipeline 14 in the right Wanggeweili shortwall working face 12.

[0039] Figure 2 As shown in Figure V: After the two densely packed Wangevili shortwall working faces on the left and right are mined, the coal pillars 13 of the remaining branch roadways on both sides of the mining-filling-solidification unit 9 are mined from the track level roadway 3 and transport level roadway 4 on both sides of the mining-filling-solidification unit 9 using a continuous miner.

[0040] Figure 2As shown in Figures VI-VIII: After the mining of the residual coal pillars 13 on both sides of the two densely mined Wangervili shortwall working faces is completed, carbon injection branch pipes 16 are inserted into each mined-out residual coal pillar 13. Immediately afterward, telescopic filling pipelines 14 are laid out from the track level roadway 3 and the transport level roadway 4 to inject filling slurry into each mined-out residual coal pillar 13. The solidification characteristics of the filling slurry are used to fix the spatial position of the carbon injection branch pipes 16, thus completing the installation of the carbon injection branch pipes 16. At this time, the inner end of each carbon injection branch pipe 16 is buried inside the filling body 15, while the outer end is left empty in the track level roadway 3 or the transport level roadway 4.

[0041] Figure 2 As shown in Figure IX-X: a carbon injection main pipe 17 is further suspended and installed in the track level 3 and the transport level 4. The carbon injection main pipe 17 is connected to the outer end of all the carbon injection branch pipes 16 in the track level 3 or the transport level 4, so as to collect the carbon injection branch pipes 16.

[0042] Preferably, the filling slurry mainly uses porous coal gangue after high-temperature calcination as aggregate, and adds cement, magnesium slag, and fly ash as chemical carbon fixation substances, and is prepared by adding water. The filling slurry, which is filled and solidified underground, can chemically fix CO2, and at the same time, it can physically adsorb and seal CO2 in the high-temperature and high-pressure underground environment, thus achieving safe and efficient CO2 sequestration through the combined action of chemical and physical processes.

[0043] Cement and fly ash act as adhesives, binding coal gangue particles together to form a load-bearing filling body 15. The hydration products of cement and cement clinker react with CO2. Magnesium slag and fly ash mainly play the role of providing magnesium and calcium sources in carbon fixation. Equations (1) to (2) are the reaction formulas of cement hydration products with CO2, equations (3) to (4) are the reaction formulas of cement clinker with CO2, and equations (5) to (7) are the reaction formulas of magnesium and calcium sources with CO2.

[0044] Ca(OH)₂ + CO₂ → CaCO₃ + H₂O (1)

[0045] CS-H+CO2→CaCO3+SiO2+nH2O (2)

[0046] C3S+3CO2+nH2O→SiO2·nH2O+3CaCO3 (3)

[0047] C2S+3CO2+nH2O→SiO2·nH2O+3CaCO3 (4)

[0048] MgO + H₂O → Mg(OH)₂ (5)

[0049] Mg(OH)₂ + CO₂ → MgCO₃ (6)

[0050] CaO + CO2 → CaCO3 (7)

[0051] like Figure 2 The flowchart of the operation of the sampling, filling and solidification unit 9 shown and Figure 3 The diagram shows the layout of the backfilling and consolidation unit 9 in the mining area. After the backfill grout in the first backfilling and consolidation unit 10 has solidified and stabilized, a dense artificial dam 18 is used to fill the adjacent unit roadway 7 behind the backfilling and consolidation unit 9. Preferably, the main material of the artificial dam 18 is C20 concrete. This material can provide airtightness, deformation resistance, and earthquake resistance, thus protecting the internal backfilling and consolidation unit 9.

[0052] like Figure 3 The schematic diagram of the layout of the mining and filling solidification unit 9 in the mining area shows that the above process is carried out sequentially on n adjacent mining and filling solidification units 9 in the same longwall working face. After the filling slurry in the last mining and filling solidification unit 9 in the longwall working face has solidified and stabilized, the two adjacent unit roadways 7 in front of and behind the last mining and filling solidification unit 9 must be filled with dense artificial dams 18 at the same time.

[0053] The above process is then repeated sequentially on each longwall working face within the mining area to complete the coal mining, backfilling, and installation of carbon injection branch pipes 16 throughout the entire mining area.

[0054] like Figure 3 The diagram shows the layout of mining and filling unit 9 in the mining area. Figure 4 The diagram showing the well layout illustrates that the carbon injection pipeline consists of carbon injection branch pipes 16, carbon injection main pipes 17, and carbon injection manifold 19. The carbon injection branch pipes 16 are inserted into the coal pillars 13 of the remaining goaf in the side roadways. The carbon injection main pipes 17 are suspended in the track level roadway 3 and the transport level roadway 4, and connect to all the carbon injection branch pipes 16 within that level roadway. The carbon injection main pipes 17 in each level roadway within the mining area are connected and converged through the carbon injection manifold 19. The carbon injection manifold 19 leads from underground to the surface, connecting to the surface carbon injection station 20. Liquid CO2 is injected from the surface carbon injection station 20, completing the carbon fixation process for all the mining, filling, and solidification units 9 within the underground mining area.

[0055] like Figure 4 The well layout diagram shown indicates that the filling slurry is prepared at the surface filling station 21 and then transported to the well via the vertical filling well 22. The lower end of the vertical filling well 22 is connected to the telescopic filling pipeline 14 in the well, and the filling slurry is injected into the working face through the telescopic filling pipeline 14.

[0056] Coal mine backfilling mining combined with carbon dioxide sequestration method:

[0057] Step a: Excavate multiple parallel level tunnels to define multiple longwall working faces; wherein, every two adjacent level tunnels form a longwall working face. Specifically, two adjacent level tunnels are track level tunnel 3 and transport level tunnel 4, and track level tunnel 3 and transport level tunnel 4 are arranged to form a longwall working face. From right to left, for the second longwall working face, the track level tunnel 3 arranged in the first longwall working face serves as the transport level tunnel 4 for the second longwall working face.

[0058] Step b: Excavate n unit roadways 7 in parallel at intervals L(6) within the longwall working face, delineate mining, filling and solidification units 9, and determine the first mining, filling and solidification unit 10; the first mining, filling and solidification unit 10 is set close to the track concentration roadway; the track concentration roadway is located behind the mining, filling and solidification unit 9; wherein, based on the same mining, filling and solidification unit 9, each unit roadway 7 is connected to two horizontal roadways.

[0059] Step c: Arrange two Wangeveli shortwall working faces, one on the left and one on the right, in a centrally symmetrical (reversely densely arranged) configuration within the first mining and filling unit 10.

[0060] Step d: A continuous miner is used to mine one Wangervili shortwall working face within the first mining and backfilling unit 10. Immediately after mining, a telescopic backfilling pipeline 14 is used for backfilling. After the backfill slurry solidifies, another Wangervili shortwall working face within the mining and backfilling unit 9 is mined and backfilled. The backfill slurry is prepared at the surface backfilling station and then transported underground through a vertical backfilling well. The bottom of the vertical backfilling well is connected to the underground telescopic backfilling pipeline 14, through which the backfill slurry is injected into the working face.

[0061] Step e: The residual branch coal pillars 13 on both sides of the two dense Wangerweili shortwall working faces in the first mining and filling unit 10 are mined. After mining, carbon injection branch pipes 16 are first inserted into each mined-out residual branch coal pillar 13, and then the telescopic filling pipeline 14 is used to fill in the carbon injection branch pipes 16 to complete the fixing and installation of the carbon injection branch pipes 16.

[0062] Step f: Fill the unit roadway 7 adjacent to the first mining and filling unit 10 to form a dense artificial dam 18;

[0063] Step g: Steps c to f are sequentially implemented for the remaining adjacent mining, filling and solidification units 9 within the same longwall working face, and finally the adjacent unit roadway 7 in front of the last mining, filling and solidification unit 9 in the longwall working face is filled to form a dense artificial dam 18.

[0064] Step h: Install carbon injection main pipes 17 in the horizontal tunnels on both sides of the first mining and filling unit 10, and collect all the carbon injection branch pipes 16 in the horizontal tunnel.

[0065] Step i: Repeat steps a to h sequentially for different longwall working faces within the mining area.

[0066] Step j: Gather all the main carbon injection pipes in the mining area to the main carbon injection pipe and connect it to the surface carbon injection station. Inject liquid CO2 into the well from the surface carbon injection station to complete the carbon fixation process of all mining, filling and solidification units in the entire mining area.

[0067] Based on the foregoing description of the present invention, and in conjunction with the geological conditions of a certain coal mine, an embodiment will be described. For example... Figure 5 The schematic diagram of the mining-filling-solidification unit embodiment shows that the distance between the track level 3 and the transport level 4 in this mine is 40m, that is, the width D(5) of the longwall working face is 40m; the length of the two Wangevil shortwall working faces in the mining-filling-solidification unit 9 is 52.43m, that is, L(6) is 52.43m; the width of the shortwall branch roadway 23 of the two Wangevil shortwall working faces is 5m, and the vertical width is 7.07m. Each Wangevil shortwall working face has 4 shortwall branch roadways 23 on the left and right sides. The width of the unit roadway above and below the mining-filling-solidification unit 9 is 5m, the length of each longwall working face is 234.7m, and 5 unit roadways are arranged in each longwall working face, resulting in 4 mining-filling-solidification units 9. Each carbon injection branch pipe 16 is 10m long, with 1m of it placed in the horizontal tunnels on both sides of the mining-filling-solidification unit 9, and 9m buried in the filling body. Four carbon injection branch pipes 16 are arranged on each side of each mining-filling-solidification unit 9, meaning a total of eight carbon injection branch pipes 16 are buried in one mining-filling-solidification unit 9. A total of 32 carbon injection branch pipes 16 are buried in each longwall working face. According to the coal mine filling mining co-coal carbon dioxide sequestration system and method disclosed in this invention, after arranging the mining-filling-solidification units 9 of the entire mining area according to the above parameters, liquid CO2 is injected underground from the surface carbon injection station 20 to achieve carbon sequestration in all mining-filling-solidification units 9 of the entire mining area.

[0068] The above are merely preferred embodiments of the present invention and do not constitute any limitation on the present invention. Any equivalent substitutions or modifications made by those skilled in the art to the technical solutions and content disclosed in the present invention without departing from the scope of the present invention shall be deemed to have remained within the protection scope of the present invention.

Claims

1. A coal mine backfilling and mining co-processing carbon dioxide sequestration system, characterized in that, include: Mining-filling-solidification unit: Two parallel horizontal tunnels are mined to define the longwall working face. Then, within the longwall working face, multiple parallel unit tunnels are excavated perpendicular to the direction of the two horizontal tunnels. Adjacent unit tunnels form a closed mining-filling-solidification unit. Each mining-filling-solidification unit contains two centrally symmetrical Wangevli shortwall working faces. Continuous mining machine: used to mine back the mining-filling-solidification unit to form the Wangevil shortwall working face. After the two Wangevil shortwall working faces are filled, the residual branch coal pillars on both sides of the two dense Wangevil shortwall working faces in each mining-filling-solidification unit are mined back. Telescopic filling pipeline: used for sequentially filling two Wangevili shortwall working faces and filling the residual coal pillars in the goaf; the telescopic filling pipeline is laid through the corresponding horizontal roadway into the Wangevili shortwall working face; the telescopic filling pipeline is retracted as needed for filling. Carbon injection pipeline: including carbon injection branch pipes and carbon injection main pipe. First, the carbon injection branch pipes are inserted into the coal pillars of each gouged residual branch roadway. Then, filling slurry is injected into each gouged residual branch roadway coal pillar through a telescopic filling pipeline. The spatial position of the carbon injection branch pipes is fixed based on the solidification characteristics of the filling slurry to complete the installation of the carbon injection branch pipes. The inner end of the carbon injection branch pipe is buried in the filling body formed by the filling slurry, and the outer end is left empty in its corresponding horizontal roadway. The carbon injection main pipe is suspended in the horizontal roadway and is connected to the outer ends of all carbon injection branch pipes in the horizontal roadway it is located in.

2. A method for co-storage of carbon dioxide during coal mine backfilling mining using the coal mine backfilling mining co-storage system as described in claim 1, characterized in that, Includes the following steps: Step a: Excavate multiple parallel horizontal tunnels to delineate multiple longwall working faces; wherein, each pair of adjacent horizontal tunnels forms a longwall working face; Step b: Excavate n unit roadways in parallel within the longwall working face, delineate mining, filling and solidification units, and determine the first mining, filling and solidification unit; the first mining, filling and solidification unit is set close to the track central roadway; the track central roadway is located behind the mining, filling and solidification unit; each unit roadway is connected to two horizontal roadways based on each mining, filling and solidification unit. Step c: Arrange two centrally symmetrical Wangevli shortwall working faces, one on the left and one on the right, within the first mining and backfilling unit; Step d: The first mining and backfilling unit uses a continuous miner to mine one of the Wanggeweili shortwall working faces. After mining, a telescopic backfilling pipeline is immediately used for backfilling. The backfilling material is a backfilling slurry prepared by adding cement, magnesium slag, and fly ash as chemical carbon fixation substances and water. After the backfilling slurry solidifies, the other Wanggeweili shortwall working face in the mining and backfilling unit is mined and backfilled. Step e: The residual branch coal pillars on both sides of the two dense Wangevili shortwall working faces in the first mining and filling unit are mined back. After mining, carbon injection branch pipes are first inserted into the residual branch coal pillars of each mined-out branch, and then the telescopic filling pipeline is used to fill in the carbon injection branch pipes to complete the fixing and installation of the carbon injection branch pipes. Step f: Fill the unit roadway located behind the first mining and backfilling unit to form an artificial dam; Step g: Repeat steps c to f for the remaining adjacent mining, filling and solidification units within the same longwall working face, and finally fill the unit roadway adjacent to the last mining, filling and solidification unit in the longwall working face to form an artificial dam. Step h: Install carbon injection main pipes in the horizontal tunnels on both sides of the first mining and backfilling unit, and collect all the carbon injection branch pipes in the horizontal tunnel. Step i: Repeat steps a~h sequentially for different longwall working faces within the mining area; Step j: Gather all the main carbon injection pipes in the mining area to the main carbon injection pipe and connect it to the surface carbon injection station. Inject liquid CO2 into the well from the surface carbon injection station to complete the carbon fixation process of all mining, filling and solidification units in the entire mining area.

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