Mine underground space response type enhanced heat storage filling system and energy storage method

Abstract

The invention provides a mine underground space response type enhanced heat storage filling system and an energy storage method. The method comprises the following specific steps: (1) coal underground space site selection; (2) preparing filling paste; (3) arranging a heat storage pipeline system; (4) arranging a resistance heating system; (5) arranging a monitoring system; (6) constructing an enhanced heat storage filling system; and (7) valley electricity / abandoned electricity / waste heat conversion, storage and utilization. According to the method, the two industries of coal mine filling mining and deep underground space energy storage are crossed and fused, the filling mining method is further innovated, the huge potential of a filling body in the aspect of supporting renewable energy sources is fully displayed, comprehensive utilization of coal mine solid waste and efficient consumption of abandoned electricity, valley electricity and the like are achieved, and the economic benefit is increased. The problem of energy storage and utilization of the coal mine goaf at the present stage is solved, and key theoretical and technical support is provided for developing new energy of the coal loading area and promoting upgrading and transformation of the coal loading area.

Description

Technical Field

[0001] The present invention relates to the field of mining engineering, and in particular to a mine underground space responsive enhanced heat storage filling system and energy storage method. Background Art

[0002] Energy storage, as a key supporting technology for the energy revolution, is an urgent need to promote large-scale access to renewable energy and improve the efficiency of power systems and regional energy systems. The underground space of mines has the advantages of large volume, stable temperature, and high pressure bearing capacity, making it an ideal place for energy storage. Overcome a series of basic theoretical and key technical problems in underground space energy storage in deep mines. At this stage, coal mining faces many pressures such as energy security, ecological environmental protection, and carbon reduction and emission reduction. The green and low-carbon development of coal is imperative. As the emission and treatment of coal-based solid wastes such as coal gangue and fly ash become more and more severe, the disposal of coal-based solid wastes has become a key link restricting the green and efficient mining of coal. Coal-based solid waste filling mining technology is in line with the main research directions of green and intelligent coal mining and clean, efficient and low-carbon utilization, and has significant technical advantages in surface subsidence control, ecological environmental protection, mine solid waste disposal and utilization, and green and low-carbon emission reduction.

[0003] In recent years, the backfill mining technology is still developing around the mine production practice and its demand for backfilling functions. However, with the new opportunities and challenges such as the intelligent upgrading of the industry, deep mining and resource utilization of coal-based solid waste, it is urgent to carry out in-depth theoretical and technical research on coal-based solid waste backfilling mining. For production mines, the high cost problem has always been the key to the widespread application of backfilling mining technology. Domestic and foreign scholars have proposed a technically and economically feasible functional backfilling mining method for a new model of carbon reduction in coal mine systems, expanding the backfilling function of traditional mines and providing a new path for the transformation and upgrading of production mines or abandoned mines. The enhanced heat storage backfilling technology in coal mine goafs effectively reduces the negative impact of coal-based solid waste on the environment, and at the same time solves the problem of reuse of backfilling materials after mining and resource depletion and well closure, providing new ideas for promoting safe, efficient, green and low-carbon development of coal and extending the life cycle of coal-bearing areas.

[0004] The existing use of underground coal space for energy storage is mainly to transform the underground space into a reservoir for storing energy, and transport the medium to be stored underground through a designed system. This includes temporary storage of certain strategic energy sources. On the other hand, the current heat storage and energy storage technology is mainly molten salt heat storage, which occupies a large area and uses less underground coal space for heat storage and energy storage; at the same time, heat storage using filling bodies is generally low-temperature heat storage, with low energy density and low heat storage efficiency.

[0005] Among the different energy storage methods, electrochemical energy storage may produce byproducts, causing serious pollution to the underground environment, compressed air energy storage may have the risk of gas explosion or leakage, lack of mature regulatory system and other problems. In the existing research on thermal energy storage using filling materials, the thermal storage temperature is generally low, and it is mostly developed in coordination with geothermal energy. The filling materials are mainly clay, fly ash, coal gangue or its binder, etc., which cannot fully meet the needs of thermal energy storage. It is urgent to develop a more economical and efficient thermal energy storage filling material and method. Summary of the invention

[0006] The purpose of the present invention is to provide a mine underground space responsive enhanced heat storage filling system and energy storage method.

[0007] The present invention is achieved through the following technical solutions:

[0008] The present invention relates to a mine underground space responsive enhanced heat storage filling system, comprising: a cable 1, a waste electricity collection system 2, a filling slurry preparation system 3, a transmission pipeline 4, an industrial waste heat storage 5, a heat energy extraction device 6, a generator 7, a user end 8, a water inlet channel 9, a water outlet channel 10, a flow meter 11, a mudstone formation 12, a sandstone formation 13, a stress sensor 14, a displacement sensor 15, a heat energy extraction pipeline 16, an enhanced heat storage filling body 17, a temperature sensor 18, and a resistance wire 19;

[0009] The active end of the heat extraction pipeline 16 is arranged inside the enhanced heat storage filling body 17, and the other end thereof is connected to the water inlet channel 9 and the water outlet channel 10 respectively;

[0010] Each layer of the enhanced heat storage filling body 17 is evenly provided with a temperature sensor 18 to monitor the temperature change in real time and transmit the data to the ground data center for analysis. At the same time, an overheating protection device is provided to automatically control related equipment based on the data analysis results. The heat storage temperature of the present invention does not exceed 200°C to ensure the stability of the filling body.

[0011] The top plate of the enhanced heat storage filling body 17 is provided with a stress sensor 14 and a displacement sensor 15 to monitor the stress and displacement of the top plate in real time to ensure the stability of the surrounding rock.

[0012] On the ground, the prepared filling paste is transported through the conveying pipeline 4 to the filling area of ​​the underground enhanced heat storage filling body 17 by the filling slurry preparation system 3. The enhanced heat storage filling body 17 needs to fill the entire underground space and connect to the top to ensure the accumulation and storage of heat. The enhanced heat storage filling body 17 needs to be consolidated and cured for at least 28 days so that it has a certain strength to support the surrounding rock and ensure the stability of the surrounding rock in the underground space.

[0013] The resistance wires 19 and the heat extraction pipelines 16 are arranged alternately in an upper and lower manner.

[0014] Preferably, the active ends of the heat extraction pipeline 16 are arranged in a double-layer configuration parallel to each other; wherein each layer is a plurality of annular pipelines arranged at equal intervals; and the resistance wire 19 is arranged between adjacent annular pipelines in each layer to achieve uniform heat distribution.

[0015] The present invention also relates to an energy storage method of the aforementioned mine underground space responsive enhanced heat storage filling system, comprising:

[0016] Step 1, site selection for underground coal space;

[0017] Step 2, preparation of filling paste;

[0018] Step 3, heat storage pipeline system layout;

[0019] Step 4, resistance heating system layout;

[0020] Step 5, monitoring system layout;

[0021] Step 6, constructing an enhanced thermal storage filling system;

[0022] Step 7: Conversion, storage and utilization of valley power / wasted power / waste heat.

[0023] Preferably, the specific steps of step 1 are as follows:

[0024] Select an area with stable strata, dense lithology, no obvious faults and karst development. The distribution of suitable strata for heat and energy storage is as follows from top to bottom: mudstone strata 12, sandstone strata 13, and the filling area of ​​enhanced heat storage filling body 17;

[0025] While ensuring the safety of the energy storage space, the heat is fully accumulated and efficiently transferred; the enhanced heat storage filling body 17 is adjacent to the sandstone 13 with high thermal conductivity, and the far end is the mudstone 12 with poor thermal conductivity, so that the heat in the enhanced heat storage filling body 17 can be quickly and efficiently transferred to the sandstone 13, thereby improving the heat exchange efficiency between the enhanced heat storage filling body 17 and the heat extraction pipeline 16. The mudstone 12 has poor thermal conductivity, which effectively inhibits the dissipation of heat energy in the filling body-sandstone, and enhances the heat storage capacity of the heat storage system.

[0026] Preferably, the specific steps of step 2 are as follows:

[0027] The components of the filling paste are mixed according to the proportions, and the proportions of the components are as follows:

[0028] Cement accounts for 8-10% of the total amount, fly ash accounts for 25-28% of the total amount, gangue accounts for 38-40% of the total amount, graphite nanoparticles account for 1-3% of the total amount, and ceramic nanoparticles account for 1-3% of the total amount.

[0029] The gangue is crushed and proportioned according to the Taybo grade, and the gangue is crushed into gangue with particle sizes of 0-5, 5-10, 10-15, and 15-20 mm, and the gangue is proportioned according to the Taybo grade. 0-5 mm accounts for 50%, 5-10 mm accounts for 21%, 10-15 mm accounts for 16%, and 15-20 mm accounts for 13%; the present invention adopts the above proportion to significantly improve the thermal physical properties of the filling body and realize efficient heat storage.

[0030] Preferably, the specific steps of step 3 are as follows:

[0031] The active end of the heat extraction pipeline 16 is pre-buried in the filling area of ​​the enhanced heat storage filling body 17 for storing and extracting heat. The layers are arranged in a ring shape, and the active end is a double-layer structure with a layer spacing of 1m. The diameter of the pipeline in each layer is 0.1m and the pipe spacing is 1m.

[0032] Preferably, the specific steps of step 4 are as follows:

[0033] In the filling area of ​​the enhanced heat storage filling body 17, resistance wires 19 are pre-installed evenly in layers. The material of the resistance wires 19 is nickel-copper. The resistance wires 19 are staggered with the heat extraction pipelines 16 at upper and lower intervals. The interval between layers is 1m, and the spacing between layers is 1m. The resistance wires are staggered with the heat storage pipelines at upper and lower intervals. The resistance wires are installed between two adjacent layers of pipelines to achieve uniform heat distribution. Among them, the heat generated by the resistance wires Q = I 2 Rt.

[0034] The electric energy comes from abandoned wind and solar power, valley electricity (hereinafter collectively referred to as waste electricity), etc. By controlling the current size and power-on time of the resistance wire, the enhanced heat storage filling body 17 is evenly heated to store heat and energy.

[0035] Preferably, the specific steps of step 5 are as follows:

[0036] Temperature sensors 18 are evenly arranged in each layer of the filling area of ​​the enhanced heat storage filling body 17 to monitor temperature changes in real time and transmit data to the ground data center for analysis. At the same time, an overheating protection device is set to automatically control related equipment based on the data analysis results. The heat storage temperature of the present invention does not exceed 200°C to ensure the stability of the filling body. Stress sensors 14 and displacement sensors 15 are arranged in the top plate of the upper stratum in the filling area of ​​the enhanced heat storage filling body 17 to monitor the stress and displacement of the top plate in real time to ensure the stability of the surrounding rock.

[0037] Preferably, the specific steps of step 6 are as follows:

[0038] The prepared filling paste is transported to the filling area of ​​the enhanced heat storage filling body 17 through the transport pipeline 4 by the filling slurry preparation system 3 to form the enhanced heat storage filling body 17;

[0039] The enhanced heat storage filling body 17 needs to fill the entire filling area and touch the top to ensure the accumulation and storage of heat; the enhanced heat storage filling body 17 needs to be consolidated and cured for at least 28 days so that it has a certain strength to support the surrounding rock and ensure the stability of the surrounding rock in the underground space.

[0040] Preferably, the specific steps of step 7 are as follows:

[0041] The waste electricity collected in the waste electricity collection system 2 is converted into stable direct current by an AC-DC converter, which is then transported underground via a cable 1. The current flows through a resistance wire 19 to heat the enhanced heat storage filling body 17 and store heat;

[0042] The heat extraction equipment 6 is used to transport the industrial waste heat in the industrial waste heat storage 5 to the underground enhanced heat storage filling body 17 through the heat extraction pipeline 16. The industrial waste heat is fully circulated in the heat extraction pipeline 16, and the heat energy is efficiently stored in the enhanced heat storage filling body 17. The sensors installed inside the enhanced heat storage filling body 17 monitor the changes of various parameters (temperature, strain, displacement, etc.) in real time.

[0043] A low-temperature heat extracting medium is injected along the water inlet channel 9 to fully circulate and extract heat in the heat extraction pipeline 16; flow meters and temperature sensors 11 are installed in the water inlet channel 9 and the water outlet channel 10 to monitor and analyze fluid flow, flow rate and temperature changes; according to actual numerical feedback, the heat extracting medium injection temperature, flow rate, and circulation number parameters are adjusted to ensure efficient extraction of heat energy;

[0044] After the heat medium reaches the target temperature, the heat extraction equipment 6 extracts it from the ground along the water outlet channel 10 and transmits it to the user end 8 for heating. When the load demand of the power system exceeds the supply capacity, the heat energy is transmitted to the generator set to drive the generator 7 to generate electricity, thereby supplementing the power gap and flexibly participating in the peak load regulation of the power grid.

[0045] The efficiency of heat extraction is

[0046] Q 管道 =c 水 m 水 (T out -T in ),

[0047] Q 充填体 =c 充填体 m 充填体 (T0-T1)

[0048] Where: c 水 is the specific heat capacity of water; m 水 is the mass of circulating water in the heat extraction pipeline 16; T outis the temperature of the water outlet channel (10); T in is the temperature of the water inlet channel 9; c 充填体 is the specific heat capacity of the filling body; m 充填体 is the mass of the filling body; T0 is the initial temperature of the enhanced heat storage filling body 17, and T1 is the temperature of the enhanced heat storage filling body 17 after heat is taken out.

[0049] The present invention has the following advantages:

[0050] (1) Medium and high temperature heat storage: At present, the functional filling technology for mine heat storage mainly adopts phase change heat storage, and its heat storage temperature is relatively low; while the present invention can achieve medium and high temperature heat storage (above 150°C), with high energy density and high thermal energy storage and utilization efficiency, which is the core direction of future development in the field of heat storage.

[0051] (2) Responsive energy storage: When the power supply is sufficient to meet the power demand, the heat storage filling system involved in the present invention will collect waste electricity resources and heat the filling body through the resistance wire. When the power supply cannot meet the demand, the heat storage filling system involved in the present invention will adopt a flexible responsive operation mode according to the demand to extract heat from the filling body to generate electricity or heat. The present invention adopts this flexible responsiveness not only to increase the economic attractiveness of the heat storage filling system, but also to improve the overall efficiency of the system by optimizing operation.

[0052] (3) Utilization of underground space in coal mines: The underground space in coal mines has the characteristics of high temperature, large volume and good stability, and is an ideal place for energy storage. After coal mining, a large amount of underground space is generated, and this space is generally not utilized. The method involved in the present invention fills the gap in energy storage in underground space of mines by planning and designing heat storage and energy storage based on underground space.

[0053] (4) Enriching the connotation of the filling body: Filling in the underground space of a coal mine is generally carried out to achieve the goals of controlling ground pressure, stabilizing the strata, and improving resource recovery rate. On this basis, the method involved in the present invention improves conventional filling materials, optimizes and improves the various heat storage properties of the filling materials, and makes it a functional carrier for achieving efficient heat storage in underground space.

[0054] (5) Resistance wire and pipeline combined heat storage mode: The conventional heat storage and extraction method is to use heat buried pipes. The method involved in the present invention converts waste electricity into thermal energy through resistance heaters and stores it in the filling body, which greatly improves the thermal energy conversion efficiency. At the same time, thermal energy such as industrial waste heat is stored in the filling body through thermal energy extraction pipelines, realizing the effective storage and utilization of industrial waste heat. During peak electricity consumption, it can also cooperate with power generation technology to fill the power gap and flexibly participate in the peak load regulation of the power grid.

[0055] (6) Extending the life cycle of mines: After coal mining, a lot of underground space is left. The method involved in the present invention makes full use of the underground space of coal mines and the existing related supporting equipment to achieve high-temperature heat and energy storage in the underground space of coal mines, turning waste into treasure, and extending the life cycle of mines. It provides theoretical reference and practical examples for my country to develop new energy in coal-bearing areas and promote the transformation and utilization of mines. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 It is a flow chart of an energy storage method of a mine underground space responsive enhanced heat storage filling system involved in the present invention;

[0057] Figure 2 It is a structural schematic diagram of a mine underground space responsive enhanced heat storage filling system involved in the present invention;

[0058] Figure 3 A schematic diagram of the site selection for the heat and energy storage layer in the present invention;

[0059] Figure 4 It is a schematic diagram of the structure of the heat energy extraction pipeline filled in the body in the present invention;

[0060] Figure 5 It is a schematic diagram of the arrangement of the resistance wire filled in the body of the present invention;

[0061] The attached drawings are marked with: 1. Cable; 2. Waste electricity collection system; 3. Filling slurry preparation system; 4. Transportation pipeline; 5. Industrial waste heat storage device; 6. Thermal energy extraction equipment; 7. Generator; 8. User end; 9. Water inlet channel; 10. Water outlet channel; 11. Flow meter; 12. Mudstone formation; 13. Sandstone formation; 14. Stress sensor; 15. Displacement sensor; 16. Thermal energy extraction pipeline; 17. Enhanced heat storage filling body; 18. Temperature sensor; 19. Resistance wire. DETAILED DESCRIPTION

[0062] The present invention is described in detail below in conjunction with specific embodiments. It should be noted that the following embodiments are only further descriptions of the present invention, but the protection scope of the present invention is not limited to the following embodiments.

[0063] Example

[0064] This embodiment relates to a mine underground space responsive enhanced heat storage filling system, see Figure 2 As shown, it includes: cable 1, waste electricity collection system 2, filling slurry preparation system 3, transmission pipeline 4, industrial waste heat storage 5, heat extraction equipment 6, generator 7, user end 8, water inlet channel 9, water outlet channel 10, flow meter 11, mudstone formation 12, sandstone formation 13, stress sensor 14, displacement sensor 15, heat extraction pipeline 16, enhanced heat storage filling body 17, temperature sensor 18, resistance wire 19;

[0065] The active end of the heat extraction pipeline 16 is arranged inside the enhanced heat storage filling body 17, and the other end thereof is connected to the water inlet channel 9 and the water outlet channel 10 respectively;

[0066] Each layer of the enhanced heat storage filling body 17 is evenly provided with a temperature sensor 18 to monitor the temperature change in real time and transmit the data to the ground data center for analysis. At the same time, an overheating protection device is provided to automatically control related equipment based on the data analysis results. The heat storage temperature of the present invention does not exceed 200°C to ensure the stability of the filling body.

[0067] The top plate of the enhanced heat storage filling body 17 is provided with a stress sensor 14 and a displacement sensor 15 to monitor the stress and displacement of the top plate in real time to ensure the stability of the surrounding rock.

[0068] On the ground, the prepared filling paste is transported through the conveying pipeline 4 to the filling area of ​​the underground enhanced heat storage filling body 17 by the filling slurry preparation system 3. The enhanced heat storage filling body 17 needs to fill the entire underground space and connect to the top to ensure the accumulation and storage of heat. The enhanced heat storage filling body 17 needs to be consolidated and cured for at least 28 days so that it has a certain strength to support the surrounding rock and ensure the stability of the surrounding rock in the underground space.

[0069] The resistance wires 19 and the heat extraction pipelines 16 are arranged alternately in an upper and lower manner.

[0070] Furthermore, the active ends of the heat extraction pipeline 16 are arranged in a double-layer configuration parallel to each other; Figure 4 As shown, each layer is composed of a plurality of annular pipes arranged at equal intervals; the resistance wire 19 is arranged between adjacent annular pipes in each layer to achieve uniform heat distribution.

[0071] This embodiment also relates to the energy storage method of the aforementioned mine underground space responsive enhanced heat storage filling system, see Figure 1 As shown, including:

[0072] Step 1, site selection of underground coal space; select an area with stable strata, dense lithology, no obvious faults and karst development, and the distribution of suitable strata for heat storage and energy storage from top to bottom is: mudstone strata 12, sandstone strata 13, and the filling area of ​​enhanced heat storage filling body 17;

[0073] While ensuring the safety of the energy storage space, it also achieves sufficient heat accumulation and efficient heat transfer;

[0074] The influence of surrounding rock type on heat storage effect is as follows: Figure 3As shown, the enhanced heat storage filling body 17 is adjacent to the sandstone 13 with high thermal conductivity, and the far end is the mudstone 12 with poor thermal conductivity, so that the heat in the enhanced heat storage filling body 17 can be quickly and efficiently transferred to the sandstone 13, thereby improving the heat exchange efficiency between the enhanced heat storage filling body 17 and the heat extraction pipeline 16. The mudstone 12 has poor thermal conductivity, which effectively inhibits the dissipation of heat energy in the filling body-sandstone, and enhances the heat storage capacity of the heat storage system.

[0075] Step 2, preparation of filling paste: the components of the filling paste are mixed according to the proportions, and the proportions of the components are as follows:

[0076] Cement accounts for 8-10% of the total amount, fly ash accounts for 25-28% of the total amount, gangue accounts for 38-40% of the total amount, graphite nanoparticles account for 1-3% of the total amount, and ceramic nanoparticles account for 1-3% of the total amount.

[0077] The gangue is crushed and proportioned according to the Taybo grade, and the gangue is crushed into gangue with particle sizes of 0-5, 5-10, 10-15, and 15-20 mm, and the gangue is proportioned according to the Taybo grade. 0-5 mm accounts for 50%, 5-10 mm accounts for 21%, 10-15 mm accounts for 16%, and 15-20 mm accounts for 13%; the present invention adopts the above proportion to significantly improve the thermal physical properties of the filling body and realize efficient heat storage.

[0078] Step 3, layout of heat storage pipeline system: pre-buried the active end of the heat extraction pipeline 16 in the filling area of ​​the enhanced heat storage filling body 17 for heat storage and extraction, the layers are arranged in a ring shape, the active end is a double-layer structure, and the layer spacing is 1m; the diameter of each layer of the pipeline is 0.1m, and the pipe spacing is 1m;

[0079] Step 4, resistance heating system arrangement: pre-install resistance wires 19 in layers and uniformly in the filling area of ​​the enhanced heat storage filling body 17, the resistance wires 19 are made of nickel copper; the resistance wires 19 and the heat extraction pipelines 16 are arranged alternately up and down; see Figure 5 As shown, the interval between layers is 1m, the interlayer spacing is 1m, and the heat storage pipes are arranged alternately above and below. Resistance wires are installed between two adjacent layers of pipes to achieve uniform heat distribution. Among them, the heat generated by the resistance wire is Q = I 2 Rt.

[0080] The source of electric energy is abandoned electricity, valley electricity (collectively referred to as waste electricity), etc. By controlling the current size and power-on time of the resistance wire, the enhanced heat storage filling body 17 is evenly heated to store heat and energy;

[0081] Step 5, monitoring system layout: Temperature sensors 18 are evenly arranged in each layer of the filling area of ​​the enhanced heat storage filling body 17 to monitor temperature changes in real time and transmit data to the ground data center for analysis. At the same time, an overheating protection device is set to automatically control related equipment based on the data analysis results. The heat storage temperature of the present invention does not exceed 200°C to ensure the stability of the filling body. Stress sensors 14 and displacement sensors 15 are arranged on the top plate of the filling area of ​​the enhanced heat storage filling body 17 to monitor the stress and displacement of the top plate in real time to ensure the stability of the surrounding rock;

[0082] Step 6, construction of enhanced heat storage filling system: the prepared filling paste is transported to the filling area of ​​the enhanced heat storage filling body 17 through the transport pipeline 4 by the filling slurry preparation system 3 to form the enhanced heat storage filling body 17;

[0083] The enhanced heat storage filling body 17 needs to fill the entire filling area and be connected to the top to ensure the accumulation and storage of heat; the enhanced heat storage filling body 17 needs to be consolidated and cured for at least 28 days so that it has a certain strength to support the surrounding rock and ensure the stability of the surrounding rock in the underground space;

[0084] Step 7: Conversion, storage and utilization of valley power / wasted power / waste heat:

[0085] The waste electricity collected in the waste electricity collection system 2 is converted into stable direct current by an AC-DC converter, which is then transported underground via a cable 1. The current flows through a resistance wire 19 to heat the enhanced heat storage filling body 17 and store heat;

[0086] The heat extraction equipment 6 is used to transport the industrial waste heat in the industrial waste heat storage 5 to the underground enhanced heat storage filling body 17 through the heat extraction pipeline 16. The industrial waste heat is fully circulated in the heat extraction pipeline 16, and the heat energy is efficiently stored in the enhanced heat storage filling body 17. The sensors installed inside the enhanced heat storage filling body 17 monitor the changes of various parameters (temperature, strain, displacement, etc.) in real time.

[0087] A low-temperature heat extracting medium is injected along the water inlet channel 9 to fully circulate and extract heat in the heat extraction pipeline 16; flow meters and temperature sensors 11 are installed in the water inlet channel 9 and the water outlet channel 10 to monitor and analyze fluid flow, flow rate and temperature changes; according to actual numerical feedback, the heat extracting medium injection temperature, flow rate, and circulation number parameters are adjusted to ensure efficient extraction of heat energy;

[0088] After the heat medium reaches the target temperature, the heat extraction equipment 6 extracts it from the ground along the water outlet channel 10 and transmits it to the user end 8 for heating. When the load demand of the power system exceeds the supply capacity, the heat energy is transmitted to the generator set to drive the generator 7 to generate electricity, thereby supplementing the power gap and flexibly participating in the peak load regulation of the power grid.

[0089] The efficiency of heat extraction is

[0090] Q 管道 =c 水 m 水 (T out -T in ),

[0091] Q 充填体 =c 充填体 m 充填体 (T0-T1)

[0092] Where: c 水 is the specific heat capacity of water; m 水 is the mass of circulating water in the heat extraction pipeline 16; T out is the temperature of the water outlet channel (10); T in is the temperature of the water inlet channel 9; c 充填体 is the specific heat capacity of the filling body; m 充填体 T0 is the initial temperature of the enhanced heat storage filling body 17, and T1 is the temperature of the enhanced heat storage filling body 17 after heat is taken out.

[0093] The present invention has the following advantages: (1) Medium and high temperature heat storage: At present, the functional filling technology of mine heat storage mainly adopts phase change heat storage, and its heat storage temperature is relatively low; while the present invention can achieve medium and high temperature heat storage (above 150°C), with high energy density and high thermal energy storage and utilization efficiency, which is the core direction of future development in the field of heat storage. (2) Responsive energy storage: When the power supply is sufficient to meet the power demand, the heat storage filling system involved in the present invention will collect waste electricity resources and heat the filling body through resistance wire. When the power supply cannot meet the demand, the heat storage filling system involved in the present invention will adopt a flexible and responsive operation mode according to the demand to extract heat from the filling body to generate electricity or heat. The present invention adopts this flexible and responsive mode, which can not only increase the economic attractiveness of the heat storage filling system, but also improve the overall efficiency of the system by optimizing operation. (3) Utilization of underground space in coal mines: The underground space in coal mines has the characteristics of high temperature, large volume and good stability, and is an ideal place for energy storage. After coal mining, a large amount of underground space is generated, and this space is generally not utilized. The method involved in the present invention fills the gap in energy storage in underground space of mines by planning and designing heat storage and energy storage based on underground space. (4) Enriching the connotation of filling body: Filling in underground space of coal mines is generally carried out to achieve the goals of controlling ground pressure, stabilizing strata and improving resource recovery rate. On this basis, the method involved in the present invention improves conventional filling materials, optimizes and improves the various heat storage properties of filling materials, and makes it a functional carrier for realizing efficient heat storage in underground space. (5) Resistance wire and pipeline combined heat storage mode: The conventional heat storage and extraction method is to use heat buried pipes. The method involved in the present invention converts waste electricity into heat energy through resistance heaters and stores it in the filling body, which greatly improves the heat energy conversion efficiency. At the same time, the heat energy extraction pipeline is used to store industrial waste heat and other heat energy in the filling body, realizing the effective storage and utilization of industrial waste heat. During the peak period of electricity consumption, it can also cooperate with power generation technology to fill the power gap and flexibly participate in the peak load regulation of the power grid. (6) Extend the life cycle of the mine: After coal mining, there is a lot of underground space left. The method involved in the present invention makes full use of the underground space of the coal mine and the existing related supporting equipment to realize the medium and high temperature heat and energy storage in the underground space of the coal mine, turning waste into treasure, and extending the life cycle of the mine. It provides theoretical reference and practical examples for my country to develop new energy in coal-bearing areas and promote the transformation and utilization of mines.

[0094] The method involved in the present invention greatly improves the utilization rate of coal-based solid waste resources, and at the same time can achieve efficient consumption and utilization of variable energy. During the period of low electricity demand, valley electricity, wind and solar power abandonment, industrial waste heat and other energies are converted into thermal energy and stored in the filling body, and the thermal energy is extracted when needed for power generation or heating. The present invention emphasizes the importance of flexible operation of the heat storage system, which can not only improve its deployment potential in the power system, but also support the decarbonization transformation of the power system by providing load tracking power generation and long-term energy storage. The method of the present invention further innovates the filling mining method, fully demonstrates the huge potential of the filling body in supporting renewable energy, and solves the current problem of energy storage utilization in coal mine goafs, and provides key theoretical and technical support for the development of new energy in coal-bearing areas and the promotion of upgrading and transformation of coal-bearing areas. It also provides a feasible solution for achieving complete decarbonization of the power system.

[0095] The application prospects of the present invention are mainly concentrated in the following aspects:

[0096] (1) Coal underground space heat storage and energy storage, converting industrial waste heat into storable thermal energy, storing it in the filling body of the goaf, and utilizing the huge volume and good heat storage performance of the filling body to achieve long-term storage of waste heat. When needed, the stored thermal energy can be extracted through pipelines to solve the problem of industrial heat and hot water and heating for residents' production and life.

[0097] (2) During the period of low electricity demand, valley electricity and abandoned wind and solar power are converted into thermal energy using resistance heat exchangers and stored in the filling body. When needed, the thermal energy is extracted through the pipeline system. During the peak period of electricity demand, a large amount of electricity is provided in conjunction with power generation technology, participating in the peak load regulation of the power grid and improving the reliability and flexibility of the power system.

[0098] (3) During coal mining, a large number of goafs are formed, which increases the risk of surface subsidence and collapse, and damages the surface ecological environment. The present invention fills the goafs in time, reduces the risk of surface subsidence and collapse, and maintains the stability of the surface ecological environment.

[0099] (4) By developing new medium- and high-temperature heat storage filling materials, the heat storage performance of the filling body is enhanced, the utilization rate of coal-based solid waste resources is improved, and the huge potential of the filling body in supporting renewable energy is fully demonstrated, ultimately achieving efficient heat and energy storage in the underground space of coal mines.

[0100] (5) By storing and extracting thermal energy, the enhanced thermal storage system provides a sustainable energy source and reduces dependence on non-renewable resources. The extracted thermal energy can be used for heating of residents and improve living comfort; at the same time, the thermal energy can also be used for power generation, participate in grid peak regulation, relieve power load pressure, and improve the stability of the power system.

[0101] In summary, the present invention has significant advantages in resource recovery, environmental protection, safe production, economic benefits, technological progress and social responsibility.

[0102] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various modifications or variations within the scope of the claims, which will not affect the essence of the present invention.

Claims

1. A mine underground space responsive enhanced heat storage filling system, characterized in that: include: Cable (1), waste electricity collection system (2), filling slurry preparation system (3), transmission pipeline (4), industrial waste heat storage (5), thermal energy extraction equipment (6), generator (7), user end (8), water inlet channel (9), water outlet channel (10), flow meter (11), mudstone formation (12), sandstone formation (13), stress sensor (14), displacement sensor (15), thermal energy extraction pipeline (16), enhanced heat storage filling body (17), temperature sensor (18), resistance wire (19); The active end of the heat extraction pipeline (16) is arranged inside the enhanced heat storage filling body (17), and the other end thereof is respectively connected to the water inlet channel (9) and the water outlet channel (10); Each layer of the enhanced heat storage filling body (17) is evenly provided with a temperature sensor (18) to monitor temperature changes in real time and transmit data to a ground data center for analysis; A stress sensor (14) and a displacement sensor (15) are arranged in the top plate of the upper stratum of the enhanced heat storage filling body (17) to monitor the stress and displacement of the top plate in real time to ensure the stability of the surrounding rock; The resistance wires (19) and the heat extraction pipelines (16) are arranged alternately in an upper and lower manner.

2. The mine underground space responsive enhanced heat storage filling system according to claim 1, characterized in that: The active end of the heat extraction pipeline (16) is arranged in a double-layer configuration parallel to each other; each layer is a structure in which a plurality of annular pipelines are arranged at equal intervals; and the resistance wire (19) is arranged between adjacent annular pipelines in each layer.

3. An energy storage method for a mine underground space responsive enhanced thermal storage filling system as claimed in claim 1, characterized in that: include: Step 1, site selection for underground coal space; Step 2, preparation of filling paste; Step 3, heat storage pipeline system layout; Step 4, resistance heating system layout; Step 5, monitoring system layout; Step 6, constructing an enhanced thermal storage filling system; Step 7: Conversion, storage and utilization of valley power / wasted power / waste heat.

4. The energy storage method of the mine underground space responsive enhanced thermal storage filling system according to claim 3, characterized in that: The specific steps of step 1 are as follows: An area with stable strata, dense lithology, no obvious faults and karst development is selected; from top to bottom, they are: mudstone strata (12), sandstone strata (13), and the filling area of ​​the enhanced heat storage filling body (17).

5. The energy storage method of the mine underground space responsive enhanced thermal storage filling system as claimed in claim 3, characterized in that: The specific steps of step 2 are as follows: Mix the components of the filling paste according to the proportions. The proportions of the components are as follows: Cement accounts for 8-10% of the total amount, fly ash accounts for 25-28% of the total amount, gangue accounts for 38-40% of the total amount, graphite nanoparticles account for 1-3% of the total amount, and ceramic nanoparticles account for 1-3% of the total amount.

6. The energy storage method of the mine underground space responsive enhanced thermal storage filling system according to claim 3, characterized in that: The specific steps of step 3 are as follows: The active end of the heat extraction pipeline (16) is pre-buried in the filling area of ​​the enhanced heat storage filling body (17), with a layer spacing of 1m; the pipeline diameter of each layer is 0.1m, and the pipe spacing is 1m.

7. The energy storage method of the mine underground space responsive enhanced thermal storage filling system according to claim 3, characterized in that: The specific steps of step 4 are as follows: The resistance wires (19) are pre-installed in layers and uniformly in the filling area of ​​the enhanced heat storage filling body (17), and the resistance wires (19) and the heat energy extraction pipelines (16) are arranged in an alternating manner with each other at intervals.

8. The energy storage method of the mine underground space responsive enhanced thermal storage filling system as claimed in claim 3, characterized in that: The specific steps of step 5 are as follows: Temperature sensors (18) are evenly arranged in each layer of the filling area of ​​the enhanced heat storage filling body (17) to monitor temperature changes in real time and transmit data to a ground data center for analysis; stress sensors (14) and displacement sensors (15) are arranged on the top plate of the filling area of ​​the enhanced heat storage filling body (17) to monitor top plate stress and displacement in real time to ensure the stability of the surrounding rock.

9. The energy storage method of the mine underground space responsive enhanced thermal storage filling system according to claim 3, characterized in that: The specific steps of step 6 are as follows: The prepared filling paste is transported by the filling slurry preparation system (3) through the transport pipeline (4) to the filling area of ​​the enhanced heat storage filling body (17), thereby forming the enhanced heat storage filling body (17).

10. The energy storage method of the mine underground space responsive enhanced thermal storage filling system according to claim 3, characterized in that: The specific steps of step 7 are as follows: The waste electricity collected in the waste electricity collection system (2) is converted into stable direct current by an AC-DC converter, and the direct current is transported to the underground via a cable (1), and the current flows through a resistance wire (19) to heat the enhanced heat storage filling body (17) and store heat; The heat extraction device (6) is used to transport the industrial waste heat in the industrial waste heat storage device (5) to the underground enhanced heat storage filling body (17) through the heat extraction pipeline (16); the industrial waste heat is fully circulated in the heat extraction pipeline (16), and the heat energy is efficiently stored in the enhanced heat storage filling body (17); A low-temperature heat extracting medium is injected along the water inlet channel (9) so that it fully circulates in the heat extraction pipeline (16) to extract heat; flow meters and temperature sensors (11) are installed in both the water inlet channel (9) and the water outlet channel (10) to monitor and analyze fluid flow, flow rate and temperature changes; and the heat extracting medium injection temperature, flow rate and circulation number parameters are adjusted according to actual numerical feedback to ensure efficient extraction of heat energy; After the heat medium reaches the target temperature, the heat extraction equipment (6) extracts it from the ground along the water outlet channel (10) and transmits it to the user end (8) for heating. When the load demand of the power system exceeds the supply capacity, the heat energy is transmitted to the generator set to drive the generator (7) to generate electricity, thereby supplementing the power gap and flexibly participating in the peak load regulation of the power grid. Among them, the extraction efficiency of heat energy Q 管道 =c 水 m 水 (T out -T in ), Q 充填体 =c 充填体 m 充填体 (T0-T1) Where: c 水 is the specific heat capacity of water; m 水 is the mass of circulating water in the heat extraction pipeline (16); T out is the temperature of the water outlet channel (10); T in is the temperature of the water inlet channel (9); c 充填体 is the specific heat capacity of the enhanced heat storage filling body (17); m 充填体 is the mass of the enhanced heat storage filling body (17); T0 is the initial temperature of the enhanced heat storage filling body (17); and T1 is the temperature of the enhanced heat storage filling body (17) after heat is taken out.

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