A goaf pressure-bearing carbon sequestration filling and carbon dioxide sealing and state dynamic monitoring method and system

Abstract

This invention discloses a method and system for co-containment and dynamic monitoring of carbon dioxide in pressurized carbon-fixing backfilling in goaf areas. The method includes: constructing a functional backfill body at a predetermined location in the goaf area to form a sealed space; deploying internal sensors within the sealed space to monitor environmental parameters and CO₂ occurrence status; deploying boundary sensors in the collapse zone, fault zone, and flexural subsidence zone of the overlying strata, as well as on the outside of the functional backfill body, to monitor structural stability and carbon dioxide leakage in real time; performing backfilling construction of the pressurized carbon-fixing backfill body into the sealed space, and simultaneously injecting carbon dioxide gas into the sealed space; transmitting the data collected by the sensors to a processing terminal to calculate the real-time carbon fixation amount and carbon fixation rate of the mineralization reaction between the pressurized carbon-fixing backfill body and carbon dioxide. This invention ensures the long-term airtightness and stability of the sealed space.

Description

Technical Field

[0001] This invention relates to the field of green coal mining and carbon sequestration technology, and in particular to a method and system for co-concentrated carbon dioxide sequestration and dynamic monitoring of the status of goaf pressure carbon fixation filling. Background Technology

[0002] With the deepening of the "dual-carbon" strategy, utilizing the vast underground space of coal mine goafs for carbon dioxide (CO2) geological sequestration has become an important technological path to achieve low-carbon mining of fossil energy. Currently, the industry mainly adopts the method of filling solid waste materials into goafs to jointly solve the problems of surface subsidence and carbon sequestration.

[0003] However, existing goaf sealing and backfilling technologies still have the following significant drawbacks in practical applications. First, the goaf has poor sealing, making it difficult to form a controlled space. After coal seam mining, the overlying strata are disturbed, forming a "three-zone" structure including caving zones and fault zones. Combined with the presence of transport roads and cut-in holes, this leads to the development of boundary fractures in the goaf. Existing technologies mostly focus on the mechanical support of the roof, lacking targeted airtight sealing construction. If CO2 is directly injected, the gas can easily leak and diffuse through the surrounding rock fractures to the working face or surface, not only causing sealing failure but also posing serious safety hazards. Second, there is a lack of precise monitoring of CO2 occurrence and carbon sequestration effects. In the complex underground environment, CO2 exists both in gaseous form and can also undergo mineralization reactions with backfill materials to be stored in solid form. Existing monitoring methods are often limited to single-point concentration detection, lacking a collaborative sensing network for environmental parameters (temperature, pressure, displacement) within the confined space and the boundary leakage status. This makes it impossible for technicians to distinguish between physical sequestration and chemical carbon fixation in real time, and makes it difficult to quantitatively evaluate the real-time carbon fixation rate of pressurized carbon-fixing fillers based on the principle of mass conservation.

[0004] Therefore, there is an urgent need for a method and system for coordinating carbon dioxide sequestration and dynamic monitoring of pressure-bearing carbon fixation filling in goaf areas, which can achieve functional sealing of goaf areas, safe carbon dioxide sequestration, and comprehensive dynamic monitoring of sequestration status and structural stability. Summary of the Invention

[0005] This invention aims to solve the problems of poor airtightness, lack of leakage monitoring, and difficulty in quantifying carbon sequestration effect in existing goaf carbon dioxide sequestration technologies. By constructing a functional filling body to form a controlled sealed space, and integrating multi-parameter sensing of the internal environment with distributed optical fiber monitoring of the external overburden "three zones", it can realize real-time early warning of goaf structural stability and CO2 leakage. At the same time, based on the principle of mass conservation, it accurately calculates the carbon sequestration rate, and provides a safe, controllable, and real-time quantifiable carbon sequestration effect method and system for pressure-bearing carbon sequestration filling and co-location of carbon dioxide in goaf, as well as dynamic status monitoring.

[0006] On the one hand, to achieve the above objectives, this invention provides a method for coordinating carbon sequestration and dynamic status monitoring of pressure-bearing carbon fixation filling in goaf areas, comprising: Functional backfill bodies are constructed at predetermined locations in the goaf, and the functional backfill bodies, together with the floor and the overlying rock, form a controlled and sealed space for carbon dioxide sequestration. An internal sensing device is deployed inside the enclosed space to form a spatial state sensing network for monitoring environmental parameters and CO2 occurrence status within the enclosed space. Boundary sensing devices are installed in the collapse zone, fracture zone, and flexural subsidence zone of the overburden and on the outside of the functional infill body to monitor the structural stability of the boundary of the enclosed space and the leakage and diffusion of carbon dioxide gas in real time. The pressurized carbon-fixed filling material is filled into the sealed space, and carbon dioxide gas is injected into the sealed space simultaneously. The data collected by the sensing device is transmitted to the processing terminal. Based on the principle of mass conservation and real-time monitored environmental parameters, the real-time carbon fixation amount and carbon fixation rate of the pressurized carbon-fixing filling material undergoing a mineralization reaction with carbon dioxide are calculated.

[0007] Preferably, constructing the functional filling body includes: Coal-based solid waste cemented backfill material is used to construct isolation walls at the cut-off point, stop line, and roadway locations; the permeability K of the solidified functional backfill body is <10⁻¹. 7 m², and the uniaxial compressive strength is greater than the periodic peak load of the goaf roof.

[0008] Preferably, the internal sensing device includes a pressure sensor, a temperature sensor, a chemical impedance sensor, a CO2 concentration sensor, and a multi-point displacement meter; the arrangement method of the pressure sensor, the temperature sensor, and the chemical impedance sensor is as follows: during the layered construction of the filling body in the sealed space, monitoring clusters are embedded along the vertical height direction of the filling body at a preset layer spacing, and each monitoring cluster integrates a pressure sensor, a temperature sensor, and a chemical impedance sensor. The pressure sensor is used to acquire stress data at different depths inside the functional filling body; the temperature sensor is used to acquire the temperature field at different depths inside the functional filling body; and the chemical impedance sensor is used to acquire the carbonization reaction state at different depths inside the functional filling body.

[0009] Preferably, the CO2 concentration sensor and the multi-point displacement meter are deployed as follows: The CO2 concentration sensors are distributed in a grid pattern on the top of the functional filling body or on the preset layered surface. The spacing between adjacent monitoring nodes of the CO2 concentration sensors is set proportionally to the directional length and the inclined length of the sealed space. The multi-point displacement gauge is placed on top of the functional filling body to monitor the connection status between the top of the filling body and the top plate, as well as the settlement of the void area.

[0010] Preferably, the boundary sensing device includes a distributed optical fiber sensor and a CO2 concentration sensor; wherein, the distributed optical fiber sensor is deployed as follows: at the contact interface between the functional backfill and the roof, floor and coal pillars on both sides, a distributed optical fiber sensor is laid along the interface to monitor the development of microcracks and strain abrupt changes at the edge of the isolation wall.

[0011] Preferably, the CO2 concentration sensor is deployed as follows: it is arranged in a vertical array through ground boreholes in the collapse zone, fracture zone, and bending subsidence zone of the overburden to monitor the gas concentration gradient at different layers and invert the sealing integrity of the overburden.

[0012] Preferably, after injecting carbon dioxide gas into the sealed space, a flow meter, a thermometer, and a pressure sensor are installed on the CO2 injection pipeline to obtain real-time data on the mass flow rate, pressure, and temperature of the CO2 injected into the sealed space.

[0013] Preferably, the real-time carbon fixation amount and carbon fixation rate of the pressurized carbon-fixing filling material in reaction with carbon dioxide are calculated, specifically as follows: M fixed =M total -M free -M leak ; ղ=M fixed / M total ×100%; In the formula, M total M represents the total mass of CO2 injected, as measured by the flow meter. free M represents the mass of free carbon dioxide; leak For the cumulative leakage mass; M fixed ղ represents the real-time carbon fixation amount; ղ represents the carbon fixation rate.

[0014] On the other hand, to achieve the above objectives, the present invention also provides a system for co-storage and dynamic monitoring of carbon dioxide in pressure-bearing carbon sequestration and backfilling in goaf areas, for realizing a method for co-storage and dynamic monitoring of carbon dioxide in pressure-bearing carbon sequestration and backfilling in goaf areas, comprising: The controlled enclosed space is formed by functional backfill bodies placed at predetermined locations in the goaf, together with the floor and the overlying rock, and is used to contain the pressurized carbon-fixing backfill bodies and seal carbon dioxide. An internal sensing device is deployed inside the enclosed space to form a spatial state sensing network for monitoring environmental parameters and CO2 occurrence status within the enclosed space. Boundary sensing devices are deployed in the collapse zone, fracture zone, and flexural subsidence zone of the overburden and on the outside of the functional infill body to monitor the structural stability of the boundary of the enclosed space and the leakage and diffusion of carbon dioxide gas in real time. The CO2 injection pipeline is pre-embedded in the sealed space and is used to inject carbon dioxide gas simultaneously during the filling construction process. The processing terminal is communicatively connected to the internal sensing device and the boundary sensing device, and is used to receive the collected data and calculate the real-time carbon fixation amount and carbon fixation rate of the pressurized carbon-fixing filling body in the mineralization reaction with carbon dioxide based on the principle of mass conservation and real-time monitored environmental parameters.

[0015] Compared with the prior art, the present invention has the following advantages and technical effects: (1) This invention transforms the goaf from a passive target for remediation into an active carbon sequestration carrier by constructing a composite structure of "functional backfill + enclosed space". The functional backfill not only plays the traditional role of supporting overlying rock and controlling surrounding rock deformation, but its material itself can also undergo a mineralization reaction with injected carbon dioxide, achieving the dual effect of carbon fixation and enhancing the performance of the backfill. This method effectively utilizes the existing underground space and rock structure in the goaf, avoiding the high cost and land requirements of constructing dedicated sequestration facilities. At the same time, the backfilling construction and gas injection process are carried out simultaneously. By utilizing the internal pores and reactivity of the backfill during the solidification process, the adsorption and mineralization efficiency of carbon dioxide is improved, realizing the integration of waste (such as slag and other materials that can be used for backfilling) resource utilization, spatial functionalization, and carbon emission reduction, significantly improving the environmental benefits and resource recycling level of the entire mineral resource development process.

[0016] (2) This invention establishes a three-dimensional monitoring system from the inside of the sealed space to the boundary of the overburden and filling body by deploying a spatial state sensing network that combines internal and external elements and coordinates multiple parameters. The pressure, temperature, concentration and displacement sensors arranged inside can provide real-time feedback on the environmental state and gas occurrence dynamics of the sealed space, while the distributed optical fiber and concentration sensors in the external "three zones" area and the boundary of the filling body can keenly detect signs of carbon dioxide leakage caused by rock fractures or defects in the filling body. This design realizes comprehensive and real-time monitoring of the "internal state-external boundary" of the sealing system. Once there is an abnormal pressure, a change in concentration gradient or a sudden increase in displacement, it can provide timely warnings and guide engineering intervention measures. In addition, based on the law of conservation of mass and real-time data calculation of carbon sequestration amount and carbon sequestration rate, not only is the sealing effect quantified, but the process and long-term stability can also be reflected through data trend analysis, providing reliable data support for the safety assessment, compliance supervision and carbon sink trading of the sealing project, greatly improving the controllability and transparency of the sealing project.

[0017] (3) From a macro perspective, this invention not only helps enterprises fulfill their carbon emission reduction responsibilities, but may also create new economic benefits by participating in carbon market trading through certified carbon sinks in the future. In addition, this invention promotes the development of mining backfill materials towards environmental protection and functionality, driving the upgrading of related industrial chains. In terms of social benefits, by achieving safe and permanent carbon dioxide sequestration, greenhouse gas emissions are reduced, contributing to the national "dual carbon" strategy; at the same time, strengthening the management of mining subsidence areas reduces the risk of surface subsidence and geological disasters, ensuring the ecological safety of mining areas and surrounding residents. This integrated method embodies the systematic thinking of "source management, process control, and end-of-pipe sequestration," providing a replicable, monitorable, and verifiable technical paradigm for the green closure and ecological transformation of similar mineral resource mining areas, and has broad industry promotion prospects and strategic significance. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a flowchart of a method for coordinating carbon dioxide sequestration and dynamic status monitoring in pressurized carbon filling of goaf areas according to an embodiment of the present invention. Figure 2 This is a schematic diagram of a goaf pressure-bearing carbon fixation and carbon dioxide sequestration and dynamic status monitoring system according to an embodiment of the present invention. Figure 3 This is a cross-sectional view of the goaf pressure-bearing carbon sequestration and dynamic status monitoring system according to an embodiment of the present invention. Figure 4 This is a top view of the goaf pressure-bearing carbon sequestration and dynamic status monitoring system for co-storage and dynamic monitoring of carbon dioxide in an embodiment of the present invention. Among them, 1. Functional filling body, 2. Monitoring cluster, 3. CO2 concentration sensor, 4. Multi-point displacement meter, and 5. Distributed optical fiber sensor. Detailed Implementation

[0019] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0020] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0021] This embodiment proposes a method for coordinating carbon sequestration and dynamic monitoring of pressure-bearing carbon fixation filling in goaf areas, such as... Figure 1 ,include: A functional filling body 1 is constructed at a predetermined location in the goaf. The functional filling body 1, together with the bottom plate and the overlying rock, forms a controlled and sealed space for carbon dioxide sequestration. An internal sensing device is deployed inside the enclosed space to form a spatial state sensing network for monitoring environmental parameters and CO2 occurrence status within the enclosed space. Boundary sensing devices are installed in the collapse zone, fracture zone, and flexural subsidence zone of the overburden and on the outside of the functional infill body to monitor the structural stability of the boundary of the enclosed space and the leakage and diffusion of carbon dioxide gas in real time. The pressurized carbon-fixed filling material is filled into the sealed space, and carbon dioxide gas is injected into the sealed space simultaneously. The data collected by the sensing device is transmitted to the processing terminal. Based on the principle of mass conservation and real-time monitored environmental parameters, the real-time carbon fixation amount and carbon fixation rate of the pressurized carbon-fixing filling material undergoing a mineralization reaction with carbon dioxide are calculated.

[0022] Specifically, including: Step 1: Construct functional backfill 1 at predetermined locations such as the opening cut on the starting side of the goaf, the stop line on the ending side, the transport roadway, and the return air roadway. The functional backfill 1, together with the bottom plate and the overlying rock, forms a controlled and sealed space for carbon dioxide sequestration. Step 2: Deploy sensing devices inside the enclosed space to form a spatial state sensing network for monitoring environmental parameters and CO2 occurrence status within the enclosed space. Step 3: Distributed fiber optic sensors 5 and CO2 concentration sensors are installed in the "three zones" area of ​​the overburden and on the outside of the functional infill body to monitor the structural stability of the sealed space boundary and the leakage and diffusion of carbon dioxide gas in real time. Step 4: After the sensor and pipeline are installed, pressurized carbon-fixed filling material is filled into the sealed space, and carbon dioxide gas is injected into the sealed space through the pre-embedded CO2 filling pipeline. Step 5: Transmit the data collected by the sensing device to the processing terminal PC via wired or wireless communication. Based on the principle of mass conservation and real-time monitored environmental parameters, calculate the real-time carbon fixation amount and carbon fixation rate of the pressurized carbon-fixing filling material in the mineralization reaction with carbon dioxide.

[0023] Furthermore, constructing the functional filling body 1 includes: Coal-based solid waste cemented backfill material is used to construct isolation walls at the cut-off point, stop line, and roadway locations; the permeability K of the solidified functional backfill body 1 is <10⁻¹. 7 m², and the uniaxial compressive strength is greater than the periodic peak load of the goaf roof.

[0024] Specifically, the construction method of functional backfill 1 is as follows: coal-based solid waste cemented backfill material is used to construct isolation walls with a width of 3m-5m at the opening, stopping line and roadway positions; the permeability K of the functional backfill after solidification is <10-17m2, and its uniaxial compressive strength is greater than the periodic peak load of the goaf roof, so as to form a pressure-bearing sealed boundary.

[0025] Furthermore, the internal sensing device includes a pressure sensor, a temperature sensor, a chemical impedance sensor, a CO2 concentration sensor, and a multi-point displacement meter 4; the arrangement method of the pressure sensor, the temperature sensor, and the chemical impedance sensor is as follows: during the layered construction of the filling body in the sealed space, monitoring clusters 2 are embedded along the vertical height direction of the filling body at a preset layer spacing, and each monitoring cluster 2 integrates a pressure sensor, a temperature sensor, and a chemical impedance sensor. The pressure sensor is used to acquire stress data at different depths inside the functional filling body; the temperature sensor is used to acquire the temperature field at different depths inside the functional filling body; and the chemical impedance sensor is used to acquire the carbonization reaction state at different depths inside the functional filling body.

[0026] The CO2 concentration sensor and the multi-point displacement meter 4 are installed as follows: The CO2 concentration sensors are distributed in a grid pattern on the top of the functional filling body or on the preset layered surface. The spacing between adjacent monitoring nodes of the CO2 concentration sensors is set proportionally to the directional length and the inclined length of the sealed space. The multi-point displacement gauge 4 is placed on top of the functional filling body to monitor the connection status between the top of the filling body and the top plate, as well as the settlement of the void area.

[0027] A dynamic three-dimensional spatial state map is constructed using monitoring data from the CO2 concentration sensor and the multi-point displacement meter.

[0028] Specifically, a three-dimensional spatial state map is constructed and updated step-by-step over time, demonstrating the evolution of CO2 concentration and displacement fields within the filling body, including migration, diffusion, and concentration. For example, the spatiotemporal overlap between regions of abnormally high CO2 concentration and regions of abrupt displacement changes may indicate the formation of crossflow channels. Simultaneously, joint monitoring with the steps described below ensures the accuracy of the relevant data.

[0029] Furthermore, the boundary sensing device includes a distributed optical fiber sensor 5 and a CO2 concentration sensor; wherein, the distributed optical fiber sensor 5 is deployed as follows: at the contact interface between the functional filling body and the roof, floor and coal pillars on both sides, the distributed optical fiber sensor 5 is laid along the interface to monitor the development of microcracks and strain changes at the edge of the sealed wall and to predict potential gas cross-flow channels.

[0030] The CO2 concentration sensor is deployed as follows: it is arranged in a vertical array through ground boreholes in the collapse zone, fracture zone, and bending subsidence zone of the overburden to monitor the gas concentration gradient at different layers and invert the sealing integrity of the overburden.

[0031] Furthermore, after injecting carbon dioxide gas into the sealed space, a flow meter, a thermometer, and a pressure sensor are installed on the CO2 injection pipeline to obtain real-time data on the mass flow rate, pressure, and temperature of the CO2 injected into the sealed space.

[0032] Furthermore, the real-time carbon fixation amount and carbon fixation rate of the pressure-bearing carbon-fixing filling material in the mineralization reaction with carbon dioxide are calculated, specifically as follows: M fixed =M total -M free -M leak ; ղ=M fixed / M total ×100%; In the formula, M total M represents the total mass of CO2 injected, as measured by the flow meter. free M represents the mass of free carbon dioxide; leak For the cumulative leakage mass; M fixed ղ represents the real-time carbon fixation amount; ղ represents the carbon fixation rate.

[0033] This embodiment also provides a system for coordinating pressurized carbon sequestration and carbon dioxide storage with dynamic status monitoring of goaf-bearing area, such as... Figure 2 , Figure 3 and Figure 4 ,include: The controlled enclosed space is formed by the functional backfill 1, which is set up at a predetermined location in the goaf, together with the bottom plate and the overlying rock, and is used to contain the pressure-bearing carbon-fixing backfill and seal carbon dioxide. An internal sensing device is deployed inside the enclosed space to form a spatial state sensing network for monitoring environmental parameters and CO2 occurrence status within the enclosed space. Boundary sensing devices are deployed in the collapse zone, fracture zone, and flexural subsidence zone of the overburden and on the outside of the functional infill body to monitor the structural stability of the boundary of the enclosed space and the leakage and diffusion of carbon dioxide gas in real time. The CO2 injection pipeline is pre-embedded in the sealed space and is used to inject carbon dioxide gas simultaneously during the filling construction process. The processing terminal is communicatively connected to the internal sensing device and the boundary sensing device, and is used to receive the collected data and calculate the real-time carbon fixation amount and carbon fixation rate of the pressurized carbon-fixing filling body in the mineralization reaction with carbon dioxide based on the principle of mass conservation and real-time monitored environmental parameters.

[0034] The beneficial effects of this technical solution include: First, this invention transforms goaf areas from passive remediation targets into active carbon sequestration carriers by constructing a composite structure of "functional backfill + enclosed space". The functional backfill not only serves the traditional functions of supporting overlying rock and controlling surrounding rock deformation, but its material itself can also undergo a mineralization reaction with injected carbon dioxide, achieving a dual effect of carbon sequestration and enhanced backfill performance. This method effectively utilizes existing underground space and rock structure in goaf areas, avoiding the high costs and land requirements of constructing dedicated sequestration facilities. Simultaneously, the backfilling construction and gas injection processes are carried out concurrently. Utilizing the internal porosity and reactivity of the backfill during solidification, the adsorption and mineralization efficiency of carbon dioxide is improved. This achieves the integration of waste (such as slag and other materials that can be used for backfilling) resource utilization, spatial functionalization, and carbon emission reduction, significantly improving the environmental benefits and resource recycling level of the entire mineral resource development process.

[0035] Secondly, this invention establishes a three-dimensional monitoring system from the interior of the sealed space to the boundary of the overburden and filling body by deploying a spatial state sensing network that combines internal and external elements and coordinates multiple parameters. Pressure, temperature, concentration, and displacement sensors arranged internally can provide real-time feedback on the environmental state and gas accumulation dynamics of the storage space, while distributed optical fibers and concentration sensors in the external "three zones" and the boundary of the filling body can sensitively detect signs of carbon dioxide leakage caused by rock fractures or defects in the filling body. This design achieves comprehensive, real-time monitoring of the "internal state-external boundary" of the storage system. Once abnormal pressure, changes in concentration gradient, or sudden increases in displacement occur, the system can issue timely warnings and guide engineering intervention measures. Furthermore, based on mass conservation and real-time data calculation of carbon sequestration quantity and rate, not only is the storage effect quantified, but data trend analysis can also reflect the process and long-term stability, providing reliable data support for the safety assessment, compliance supervision, and carbon trading of storage projects, greatly improving the controllability and transparency of storage projects.

[0036] Finally, from a macroeconomic perspective, it not only helps enterprises fulfill their carbon emission reduction responsibilities but may also create new economic benefits by participating in carbon market trading through certified carbon sinks. Furthermore, this technology promotes the development of mining backfill materials towards environmental friendliness and functionality, driving the upgrading of related industrial chains. In terms of social benefits, by achieving the safe and permanent sequestration of carbon dioxide, it reduces greenhouse gas emissions, contributing to the national "dual-carbon" strategy; simultaneously, strengthening the management of mining subsidence areas reduces the risk of surface subsidence and geological disasters, ensuring the ecological safety of mining areas and surrounding residents. This integrated approach embodies a systematic approach of "source control, process control, and end-of-pipe sequestration," providing a replicable, monitorable, and verifiable technological paradigm for the green closure and ecological transformation of similar mineral resource mining areas, possessing broad industry promotion prospects and strategic significance.

[0037] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for co-storage and dynamic monitoring of carbon dioxide in pressure-bearing carbon sequestration filling in goaf areas, characterized in that, include: Functional backfill bodies are constructed at predetermined locations in the goaf, and the functional backfill bodies, together with the floor and the overlying rock, form a controlled and sealed space for carbon dioxide sequestration. An internal sensing device is deployed inside the enclosed space to form a spatial state sensing network for monitoring environmental parameters and CO2 occurrence status within the enclosed space. Boundary sensing devices are installed in the collapse zone, fracture zone, and flexural subsidence zone of the overburden and on the outside of the functional infill body to monitor the structural stability of the boundary of the enclosed space and the leakage and diffusion of carbon dioxide gas in real time. The pressurized carbon-fixed filling material is filled into the sealed space, and carbon dioxide gas is injected into the sealed space simultaneously. The data collected by the sensing device is transmitted to the processing terminal. Based on the principle of mass conservation and real-time monitored environmental parameters, the real-time carbon fixation amount and carbon fixation rate of the pressurized carbon-fixing filling material undergoing a mineralization reaction with carbon dioxide are calculated.

2. The method for co-storage and dynamic monitoring of carbon dioxide in pressure-bearing carbon sequestration in goaf areas according to claim 1, characterized in that, Constructing the functional filling body includes: Coal-based solid waste cemented backfill material is used to construct isolation walls at the cut-off point, stop line, and roadway locations; the permeability K of the solidified functional backfill body is <10⁻¹. 7 m², and the uniaxial compressive strength is greater than the periodic peak load of the goaf roof.

3. The method for co-storage and dynamic monitoring of carbon dioxide in pressure-bearing carbon sequestration in goaf areas according to claim 1, characterized in that, The internal sensing device includes a pressure sensor, a temperature sensor, a chemical impedance sensor, a CO2 concentration sensor, and a multi-point displacement meter; the arrangement method of the pressure sensor, the temperature sensor, and the chemical impedance sensor is as follows: during the layered construction of the filling body in the sealed space, monitoring clusters are embedded along the vertical height direction of the filling body at a preset layer spacing, and each monitoring cluster integrates a pressure sensor, a temperature sensor, and a chemical impedance sensor. The pressure sensor is used to acquire stress data at different depths inside the functional filling body; the temperature sensor is used to acquire the temperature field at different depths inside the functional filling body; and the chemical impedance sensor is used to acquire the carbonization reaction state at different depths inside the functional filling body.

4. The method for co-storage and dynamic monitoring of carbon dioxide in pressure-bearing carbon sequestration in goaf areas according to claim 3, characterized in that, The deployment method of the CO2 concentration sensor and the multi-point displacement meter is as follows: The CO2 concentration sensors are distributed in a grid pattern on the top of the functional filling body or on the preset layered surface. The spacing between adjacent monitoring nodes of the CO2 concentration sensors is set proportionally to the directional length and the inclined length of the sealed space. The multi-point displacement gauge is placed on top of the functional filling body to monitor the connection status between the top of the filling body and the top plate, as well as the settlement of the void area.

5. The method for co-storage and dynamic monitoring of carbon dioxide in pressure-bearing carbon sequestration in goaf areas according to claim 1, characterized in that, The boundary sensing device includes a distributed optical fiber sensor and a CO2 concentration sensor; wherein, the distributed optical fiber sensor is deployed as follows: at the contact interface between the functional backfill and the roof, floor and the coal pillars on both sides, the distributed optical fiber sensor is laid along the interface to monitor the development of microcracks and strain abrupt changes at the edge of the isolation wall.

6. The method for co-storage and dynamic monitoring of carbon dioxide in pressure-bearing carbon sequestration in goaf areas according to claim 5, characterized in that, The CO2 concentration sensor is deployed as follows: it is arranged in a vertical array through ground boreholes in the collapse zone, fracture zone, and bending subsidence zone of the overburden to monitor the gas concentration gradient at different layers and invert the sealing integrity of the overburden.

7. The method for co-storage and dynamic monitoring of carbon dioxide in pressure-bearing carbon sequestration and backfilling in goaf areas according to claim 1, characterized in that, After injecting carbon dioxide gas into the sealed space, a flow meter, a thermometer, and a pressure sensor are also installed on the CO2 injection pipeline to obtain real-time data on the mass flow rate, pressure, and temperature of the CO2 injected into the sealed space.

8. The method for co-storage and dynamic monitoring of carbon dioxide in pressure-bearing carbon sequestration in goaf areas according to claim 1, characterized in that, The real-time carbon fixation amount and carbon fixation rate of the pressure-bearing carbon-fixing backfill reacting with carbon dioxide are calculated as follows: M fixed =M total -M free -M leak ; gh=M fixed / M total ×100%; In the formula, M total M represents the total mass of CO2 injected, as measured by the flow meter. free M represents the mass of free carbon dioxide; leak For the cumulative leakage mass; M fixed ղ represents the real-time carbon fixation amount; ղ represents the carbon fixation rate.

9. A system for co-storage and dynamic monitoring of carbon dioxide in pressure-bearing goaf, used to implement the method for co-storage and dynamic monitoring of carbon dioxide in pressure-bearing goaf as described in any one of claims 1-8, characterized in that, include: The controlled enclosed space is formed by functional backfill bodies placed at predetermined locations in the goaf, together with the floor and the overlying rock, and is used to contain the pressurized carbon-fixing backfill bodies and seal carbon dioxide. An internal sensing device is deployed inside the enclosed space to form a spatial state sensing network for monitoring environmental parameters and CO2 occurrence status within the enclosed space. Boundary sensing devices are deployed in the collapse zone, fracture zone, and flexural subsidence zone of the overburden and on the outside of the functional infill body to monitor the structural stability of the boundary of the enclosed space and the leakage and diffusion of carbon dioxide gas in real time. The CO2 injection pipeline is pre-embedded in the sealed space and is used to inject carbon dioxide gas simultaneously during the filling construction process. The processing terminal is communicatively connected to the internal sensing device and the boundary sensing device, and is used to receive the collected data and calculate the real-time carbon fixation amount and carbon fixation rate of the pressurized carbon-fixing filling body in the mineralization reaction with carbon dioxide based on the principle of mass conservation and real-time monitored environmental parameters.

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