A gas-solid two-phase carbon sequestration method based on a working face equilateral triangular structure filling

Abstract

This invention provides a gas-solid two-phase carbon sequestration method based on a triangular structure filling in the working face, applicable to geological scenarios such as stable roof lithology. First, a sealed carbon storage chamber is constructed in the filling area, and filling and venting pipelines are arranged. A filling material containing gangue, a fast and efficient cementing material, and based on mineral carbonization as the reaction mechanism is used. The carbon storage chamber is formed through a paste filling system and a solid-phase carbon storage support. Utilizing the gas-phase carbon storage support in conjunction with the solid-phase support, carbon dioxide is injected into the chamber to replace the existing gas. After reaching the required standard, the valve is closed to achieve long-term storage. This method integrates filling support and carbon sequestration, reducing leakage risk through both physical and chemical sequestration, and also consumes gangue, offering both environmental and safety benefits.

Description

Technical Field

[0001] This invention relates to the field of coal mine backfilling technology, specifically a gas-solid two-phase carbon sequestration method based on a triangular structure backfilling of the working face, which is particularly suitable for specific geological scenarios such as stable roof lithology. Background Technology

[0002] Achieving the "dual carbon" target is a major national strategic requirement. Coal mine backfilling mining technology, as a core technology for green mine construction, plays a crucial role in the field of coal resource development. It can not only effectively improve the coal extraction rate and reduce resource waste, but also significantly control surface subsidence, protect the surface ecological environment and infrastructure, and provide important technical support for the sustainable development of mines.

[0003] However, traditional backfilling techniques have significant limitations. Their main function is to support the overburden with the backfill material, failing to fully exploit the enormous spatial resource potential of goaf areas, resulting in the idle and wasted space. Furthermore, directly injecting carbon dioxide into goaf areas for sequestration lacks a stable and effective engineering structure to create a long-term sealed storage environment, easily leading to carbon dioxide leakage and compromising the safety and stability of the sequestration. In addition, while common solid backfilling techniques can handle solid waste such as gangue and provide roof support, the solid materials themselves have limited carbon dioxide sequestration capacity, making it difficult to meet the needs of large-scale, long-term carbon sequestration and hindering the further application of backfilling technology in achieving the "dual carbon" goals. Summary of the Invention

[0004] To address the aforementioned technical shortcomings, the purpose of this invention is to provide a gas-solid two-phase carbon sequestration method based on a triangular structure filling of the working face, thereby solving the problems of traditional filling technology being unable to utilize the vast spatial resources of the goaf and the limited carbon dioxide sequestration capacity of general solid filling solid phase materials.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A gas-solid two-phase carbon sequestration method based on a triangular structure filling at the working face includes the following steps:

[0007] Step 1: Design and construct a series of sealed carbon storage chamber structures within the filling area, and pre-arrange carbon dioxide filling and exhaust pipes on the bottom and top plates of the designed and constructed sealed carbon storage chambers.

[0008] Step 2: Using a mixture of normal or supercritical CO2, gangue, and rapid and efficient cementing materials, mineral carbonization filling material with "mineral carbonization" as the reaction mechanism is used to fill the goaf through a paste filling system according to the design; a preliminary filling body outline is formed using a solid phase carbon storage filling support, and planned structural filling is carried out to form a series of carbon storage chamber structural spaces that meet the design requirements in the goaf;

[0009] Step 3: Use auxiliary flexible materials to enhance the airtightness of the top / bottom area, ensuring a tight seal between the carbon storage chamber structure and the top. Once the mineral carbonized filling material has tightly sealed the top, forming a series of carbon storage chamber structures, utilize gas-phase carbon storage support structures positioned corresponding to the carbon storage chamber structures. The gas-phase carbon storage support structures and solid-phase carbon storage filling support structures work together to inject carbon dioxide gas into the sealed carbon storage chamber structure structures through the inflation pipeline, while simultaneously expelling the original gas within the sealed carbon storage chamber structure structures through the exhaust pipeline. A high-precision carbon dioxide concentration sensor is installed at the exhaust pipeline. When the sensor data shows a preset carbon dioxide concentration maintained for a period of time, it can be determined that the gas within the chamber space has been completely replaced by carbon dioxide.

[0010] Step 4: Once the carbon dioxide level in the sealed carbon storage chamber reaches the design value, close the inflation and deflation valves to allow the carbon dioxide to be stored in the sealed carbon storage chamber for an extended period. The connection between the inflation and deflation lines and the gas phase carbon storage support uses high-pressure self-sealing quick-connect couplings. When it is necessary to move the gas phase carbon storage support to begin the next step, the operator uses a rotating buckle to separate the quick-connect coupling from the interface on the gas phase carbon storage support side. At the moment of separation, the spring-driven valve core inside the quick-connect coupling immediately and automatically resets, simultaneously sealing the inflation and deflation lines and the gas phase carbon storage support side to prevent carbon dioxide leakage from the chamber and the intrusion of external air or moisture.

[0011] Preferably, the shape, size, and distribution of the carbon storage chamber structure are dynamically designed based on geological conditions and storage requirements.

[0012] Preferably, the solid-phase carbon storage filling support and the gas-phase carbon storage sealing support are functionally independent but work together in the execution process; the solid-phase carbon storage filling support and the gas-phase carbon storage sealing support are arranged alternately on the working face, and only a few gas-phase carbon storage sealing supports are arranged in front of a sealed carbon storage chamber structure space according to the volume of the sealed carbon storage chamber structure space and the filling and venting capacity, while the other supports are solid-phase carbon storage filling supports.

[0013] Preferably, the carbon dioxide injection operation and the filling operation are staggered in time and implemented sequentially in a regional and phased manner.

[0014] Preferably, the mineral carbonized filling material undergoes a carbonization reaction with carbon dioxide to form permanent carbonate minerals, which are used to enhance the stability of the storage.

[0015] Preferably, the gas phase carbon storage support is equipped with an inflation pipe and an exhaust pipe, and integrates a pipeline control system, valve group, monitoring instruments, safety monitoring system, and pressure monitoring system. The pipeline control system is used to enable the inflation and exhaust pipes to quickly connect to the gas phase carbon storage support. The valve group is used to precisely control the inflation and exhaust rates. The monitoring instruments and safety monitoring system are used to monitor the real-time status of the inflation and exhaust pipes and the internal pressure of the cavity space, and to promptly alarm when abnormal data occurs. The pressure monitoring system is used to monitor the stress state of the support and the pipeline pressure.

[0016] Preferably, the inflation pipeline and the exhaust pipeline are integrated with control valves and carbon dioxide concentration sensors for regulating the carbon injection process and monitoring the storage status. The carbon dioxide concentration sensor is used to monitor the carbon dioxide concentration at the exhaust pipeline. When the carbon dioxide concentration in the exhaust gas shows a stable upward trend, and then the carbon dioxide concentration remains stable at a preset threshold for a period of time, it can be determined that the gas in the sealed carbon storage chamber has been highly replaced by the injected carbon dioxide.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] This invention is the first to integrate the roof support function and carbon dioxide sequestration function of backfilling mining within the goaf, overcoming the limitations of traditional backfilling technologies that fail to make reasonable use of the vast space resources of the goaf and the insufficient carbon dioxide sequestration capacity of general solid backfill materials (such as paste backfill). By constructing a structurally complete, sealed carbon storage chamber, a stable geological container for carbon dioxide is provided. Combined with mineral carbonization, a dual guarantee mechanism of "physical sequestration" and "chemical sequestration" is formed, significantly reducing the risk of leakage and further enhancing the roof support capacity of the backfill. This process arranges the gas phase sequestration system and the solid phase backfilling system in parallel, with the processes sequentially connected rather than performed simultaneously, minimizing the potential impact of carbon injection on mining safety. This process utilizes the space resources of the goaf as a carbon sequestration reservoir, while consuming waste materials such as gangue generated during coal mining, achieving the dual environmental benefits of reducing solid waste accumulation and storing carbon dioxide. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the gas-solid two-phase carbon sequestration process based on the triangular structure filling of the working face according to the present invention.

[0020] Figure 2 This is a location diagram of the gas phase carbon storage and sealing support system of the present invention.

[0021] Figure 3 This is a location diagram of the solid-phase carbon storage filling support system of the present invention.

[0022] in:

[0023] 1. Filling area; 2. Mineral carbonized filling material; 3. Carbon storage chamber structure; 4. Gas filling pipeline; 5. Exhaust pipeline; 6. Gas phase carbon storage and sealing support; 7. Solid phase carbon storage and filling support; 8. Negative carbon filling working surface; 9. Carbon dioxide filling system; 10. Existing gas exhaust system; 11. Paste filling system. Detailed Implementation

[0024] The invention will now be further described with reference to the accompanying drawings.

[0025] like Figures 1 to 3 As shown, a gas-solid two-phase carbon sequestration method based on a triangular structure filling at the working face includes the following steps:

[0026] Step 1: Design and construct a series of sealed carbon storage chamber structures 3 in the filling area 1 on the side of the negative carbon filling working face 8. Arrange the filling pipeline 4 of the carbon dioxide filling system 9 and the exhaust pipeline 5 of the original gas exhaust system 10 in advance on the bottom plate and top plate of the designed and constructed sealed carbon storage chamber.

[0027] Step 2: Using a mixture of normal or supercritical CO2, gangue, and fast and efficient cementing materials, mineral carbonization filling material 2 with "mineral carbonization" as the reaction mechanism is used to fill the goaf through the paste filling system 11 according to the design; the solid phase carbon storage filling support 7 is used to form a preliminary filling body outline, and the planned structural filling is carried out to form a series of carbon storage chamber structure spaces 3 that meet the design requirements in the goaf;

[0028] Step 3: To ensure the carbon storage chamber structure 3 is tightly connected to the top, auxiliary flexible materials such as hay and wood stacks can be used to enhance the airtightness of the top / bottom area, making the carbon storage chamber structure 3 tightly connected to the top. After the mineral carbonized filling material 2 tightly connects to the top to form a series of carbon storage chamber structure spaces 3, the gas phase carbon storage sealing support 6, which is arranged at the position corresponding to the carbon storage chamber structure space 3, works in conjunction with the solid phase carbon storage filling support 7 to pressurize carbon dioxide gas into the sealed carbon storage chamber structure space 3 through the gas filling pipeline 4, and at the same time, the original gas in the sealed carbon storage chamber structure space 3 is discharged through the exhaust pipeline 5. A high-precision carbon dioxide concentration sensor is installed at the exhaust pipeline 5. When the sensor data shows that the preset high carbon dioxide concentration is maintained for a period of time, it can be determined that the gas in the chamber space has been completely replaced by carbon dioxide.

[0029] Step 4: When the carbon dioxide level in the sealed carbon storage chamber 3 reaches the design value, close the inflation and deflation valves to allow the carbon dioxide to be stored in the sealed carbon storage chamber 3 for an extended period. The connection between the inflation pipeline 4, the deflation pipeline 5, and the gas phase carbon storage support 6 uses a high-pressure self-sealing quick connector. When it is necessary to move the gas phase carbon storage support 6 to begin the next step, the operator separates the quick connector from the interface on the side of the gas phase carbon storage support 6 by rotating the buckle. At the moment of separation, the spring-driven valve core inside the quick connector immediately and automatically resets, simultaneously sealing the inflation pipeline 4, the deflation pipeline 5, and the gas phase carbon storage support 6 to prevent carbon dioxide leakage from the chamber and the intrusion of external air or moisture.

[0030] Furthermore, the carbon storage chamber structure space 3 is designed according to the roof lithology, support conditions, and carbon dioxide sequestration capacity requirements. Its size is controlled by the filling step distance and reserved intervals.

[0031] Furthermore, the shape, size, and distribution of the sealed carbon storage chamber structure space 3 are dynamically designed according to geological conditions and storage requirements.

[0032] Furthermore, to ensure the easy sealing and high airtightness of the enclosed carbon storage chamber structure space 3, this technology is applicable to situations where the top and bottom plates have good conditions.

[0033] Furthermore, the solid-phase carbon storage filling support 7 and the gas-phase carbon storage sealing support 6 are functionally independent, but they work together in the execution process. The solid-phase carbon storage filling support 7 and the gas-phase carbon storage sealing support 6 are arranged alternately on the working face. Only a few gas-phase carbon storage sealing supports 6 are arranged in front of a closed carbon storage chamber structure space 3 according to the volume of the closed carbon storage chamber structure space 3 and the filling and venting capacity. The other supports are solid-phase carbon storage filling supports 7.

[0034] Furthermore, the carbon dioxide injection and filling operations are staggered in timing and implemented sequentially in a regional and phased manner.

[0035] Furthermore, the mineral carbonized filling material 2 can undergo a carbonization reaction with carbon dioxide to form permanent carbonate minerals, further enhancing the stability of the storage.

[0036] Furthermore, the vapor phase carbon storage support 6 is equipped with an inflation pipe and an exhaust pipe, and integrates a pipeline control system, valve group, monitoring instruments and safety monitoring system, and pressure monitoring system. The pipeline control system is used to enable the inflation pipe 4 and exhaust pipe 5 to quickly connect with the vapor phase carbon storage support 6. The valve group is used to precisely control the inflation and exhaust rates. The monitoring instruments and safety monitoring system are used to monitor the real-time status of the inflation pipe 4 and exhaust pipe 5 and the internal pressure of the cavity space, and to promptly alarm when abnormal data occurs (such as the data monitored by the pressure monitoring system exceeding the threshold). The pressure monitoring system is used to monitor the stress state of the support and the pipeline pressure.

[0037] Furthermore, the inflation line 4 and the exhaust line 5 are integrated with control valves and carbon dioxide concentration sensors for regulating the carbon injection process and monitoring the storage status. The carbon dioxide concentration sensor is used to monitor the carbon dioxide concentration at the exhaust line 5. When the carbon dioxide concentration in the exhaust gas shows a stable upward trend, and then the carbon dioxide concentration remains stable at a preset threshold for a period of time, it can be determined that the gas in the sealed carbon storage chamber structure space 3 has been highly replaced by the injected carbon dioxide.

[0038] Example:

[0039] First, after the coal mine working face advances, a new technology is deployed in the space behind the goaf. This technology innovatively integrates a "gas-phase sealed carbon storage system" based on the traditional paste filling system for solid carbon dioxide filling. It mainly consists of a carbon dioxide filling system and a filling and venting system, which are arranged in parallel with the paste filling system.

[0040] The core equipment, the "dual-phase synergistic carbon storage and filling support," is installed at the working face. The solid-phase carbon storage and filling support 7 is used to construct the boundary of the filling body, and its function is similar to that of a traditional paste-filling support, primarily forming a stable, sealed structural space. The gas-phase carbon storage and sealing support 6 is used for the final sealing of carbon dioxide. It can be modified from a traditional slurry-blocking support by adding airtight sealing elements, an air filling and venting system, and pipeline modifications.

[0041] Within the space enclosed by a support frame, the filling operation is carried out using mineral carbonized filling material 2. This material is prepared by mixing normal or supercritical CO2, gangue, and a fast and efficient cementing material. It can form a high-strength filling body and also has the ability to react with carbon dioxide to form permanent carbonate minerals. Before the entire process begins, air filling pipes 4 and air venting pipes 5 must be pre-laid on the top and bottom plates of the space to be filled. These pipes will be permanently buried in the filling body and have external interfaces.

[0042] After the filling material solidifies, a complete and tightly sealed carbon storage chamber structure 3 is formed. Once the airtightness of the chamber is confirmed, carbon sequestration operations can be initiated. Carbon dioxide gas is injected into the sealed chamber through a pre-installed inflation pipeline 4, while the exhaust pipeline 5 is used to vent, monitor, and regulate the pressure inside the chamber to ensure the safety of the sequestration process. Ultimately, permanent gaseous sequestration of carbon dioxide is achieved within the goaf.

Claims

1. A gas-solid two-phase carbon sequestration method based on working face equilateral triangular structure filling, characterized in that, Includes the following steps: Step 1: Design and construct a series of sealed carbon storage chamber structures (3) in the filling area (1), and arrange carbon dioxide filling pipes (4) and exhaust pipes (5) in advance on the bottom plate and top plate of the designed and constructed sealed carbon storage chamber. Step 2: Using a mineral carbonization filling material (2) with a reaction mechanism of "mineral carbonization" by mixing normal or supercritical CO2, gangue and fast and efficient cementing materials, the goaf is filled through a paste filling system (11) according to the design; a preliminary filling body outline is formed by using a solid carbon storage filling support (7), and a planned structural filling is carried out to form a series of carbon storage chamber structure spaces (3) that meet the design requirements in the goaf; Step 3: Use auxiliary flexible materials to enhance the sealing of the top / bottom area, so that the carbon storage chamber structure space (3) is tightly connected to the top; after the mineral carbonized filling material (2) is tightly connected to the top to form a series of carbon storage chamber structure spaces (3), use the gas phase carbon storage sealing support (6) arranged at the position corresponding to the carbon storage chamber structure space (3), the gas phase carbon storage sealing support (6) and the solid phase carbon storage filling support (7) work together to inject carbon dioxide gas into the sealed carbon storage chamber structure space (3) through the gas filling pipeline (4), and at the same time discharge the original gas in the sealed carbon storage chamber structure space (3) through the exhaust pipeline (5); install a high-precision carbon dioxide concentration sensor at the exhaust pipeline (5), when the sensor data shows that the preset carbon dioxide concentration is maintained for a period of time, it can be determined that the gas in the chamber space has been completely replaced by carbon dioxide; Step 4: When the amount of carbon dioxide filled into the sealed carbon storage chamber (3) reaches the design value, close the filling and exhaust valves to allow the carbon dioxide to be stored in the sealed carbon storage chamber (3) for a long time. The connection between the filling pipeline (4), the exhaust pipeline (5) and the gas phase carbon storage support (6) adopts a high-pressure self-sealing quick connector. When it is necessary to move the gas phase carbon storage support (6) to start the next step, the operator separates the quick connector from the interface on the side of the gas phase carbon storage support (6) by rotating the buckle. At the moment of separation, the spring-driven valve core set inside the quick connector immediately resets automatically, and the filling pipeline (4), the exhaust pipeline (5) and the gas phase carbon storage support (6) are sealed simultaneously to prevent carbon dioxide leakage in the chamber and the intrusion of external air or moisture.

2. A gas-solid two-phase carbon sequestration method based on the working face equilateral triangular structure filling of claim 1, wherein, The shape, size and distribution of the carbon storage chamber structure (3) are dynamically designed according to geological conditions and storage requirements.

3. The gas-solid two-phase carbon sequestration method based on a triangular structure filling at the working face as described in claim 1, characterized in that, The solid carbon storage filling support (7) and the gaseous carbon storage sealing support (6) are functionally independent, but work together in the process. The solid carbon storage filling support (7) and the gaseous carbon storage sealing support (6) are arranged alternately on the working face. Only a few gaseous carbon storage sealing supports (6) are arranged in front of a closed carbon storage chamber structure space (3) according to the volume of the closed carbon storage chamber structure space (3) and the filling and venting capacity. The other supports are solid carbon storage filling supports (7).

4. The gas-solid two-phase carbon sequestration method based on a triangular structure filling at the working face as described in claim 1, characterized in that, The carbon dioxide injection and filling operations are staggered in time and carried out sequentially in a regional and phased manner.

5. The gas-solid two-phase carbon sequestration method based on a triangular structure filling at the working face as described in claim 1, characterized in that, The mineral carbonized filling material (2) reacts with carbon dioxide to form permanent carbonate minerals, which are used to enhance the stability of the storage.

6. A gas-solid two-phase carbon sequestration method based on the working face equilateral triangular structure filling of claim 1, wherein, The gas phase carbon storage support (6) is equipped with an inflation pipe and an exhaust pipe, and integrates a pipeline control system, valve group, monitoring instruments, safety monitoring system and pressure monitoring system; the pipeline control system is used to enable the inflation pipe (4) and exhaust pipe (5) to quickly connect with the gas phase carbon storage support (6); the valve group is used to precisely control the inflation and exhaust rates; The monitoring instruments and safety monitoring system are used to monitor the real-time status of the inflation pipeline (4) and the exhaust pipeline (5) and the internal pressure of the cavity space, and to promptly alarm when abnormal data occurs; the pressure monitoring system is used to monitor the stress status of the support and the pipeline pressure.

7. A gas-solid two-phase carbon sequestration method based on a triangular structure filling at the working face, as described in any one of claims 1 to 6, characterized in that, The inflation line (4) and the exhaust line (5) are integrated with control valves and carbon dioxide concentration sensors to regulate the carbon injection process and monitor the storage status. The carbon dioxide concentration sensor is used to monitor the carbon dioxide concentration at the exhaust line (5). When the carbon dioxide concentration in the exhaust gas shows a stable upward trend, and then the carbon dioxide concentration remains stable at the preset threshold, and this stable state is maintained for a period of time, it can be determined that the gas in the sealed carbon storage chamber structure space (3) has been highly replaced by the injected carbon dioxide.

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