Mining area-oriented Carnot cell and carbon dioxide enhanced geothermal system and method thereof

Abstract

The invention discloses a mine-area-oriented Carnot cell and carbon dioxide enhanced geothermal system which comprises an sCO2-EGS subsystem, the sCO2-EGS subsystem is connected with a Carnot cell subsystem through a pipeline, the Carnot cell subsystem is connected with a mine water waste heat utilization subsystem through a pipeline, the sCO2-EGS subsystem is further connected with a gas waste heat utilization subsystem through a pipeline, and the gas waste heat utilization subsystem is connected with a gas waste heat utilization subsystem through a pipeline. The sCO2-EGS, the Carnot cell, the mine water waste heat utilization device and the gas waste heat utilization device are connected with the power bus through wires. The invention further discloses an operation method of the mining area-oriented Carnot cell and carbon dioxide enhanced geothermal system. According to the geothermal system and the method thereof, the problems that in an existing mine area geothermal system, power is generated only through a supercritical carbon dioxide enhanced geothermal power generation system, so that the energy utilization efficiency is low, the working medium flow is reduced, and electric energy supply and demand are unbalanced are solved.

Description

Technical Field

[0001] This invention belongs to the field of energy conservation and carbon reduction technology in mining areas, specifically involving Carnot batteries and carbon dioxide-enhanced geothermal systems for mining areas, and also involving the operation method of Carnot batteries and carbon dioxide-enhanced geothermal systems for mining areas. Background Technology

[0002] With the gradual depletion of shallow coal resources, the mining of deep coal seams has become an inevitable trend. However, the high-temperature heat hazards in deep mines have seriously affected normal mining activities. In fact, this high-temperature heat hazard is a sustainable geothermal energy source. In addition, coal mining areas are usually located in remote areas with large electricity demand and face significant emission reduction pressures. Geothermal power generation can provide an effective solution to the above pain points.

[0003] Geothermal power generation is characterized by its cleanliness, environmental friendliness, and stable output. It typically utilizes hydrothermal geothermal energy with temperatures above 150℃ and enhanced geothermal energy (hot dry rock) at depths of over 3000m. In coal mining areas, enhanced geothermal power generation (EGS) offers significant advantages, such as sufficient mining depth, years of mining accumulating detailed hydrogeological data, and relatively complete supporting infrastructure, thus greatly reducing development costs and exploration risks. EGS typically uses water as the working fluid, while supercritical carbon dioxide (sCO2) has advantages such as low viscosity, high inertness, and good compressibility, which helps improve heat exchange and power generation efficiency, enhance power generation flexibility, and reduce equipment corrosion. Furthermore, it allows for simultaneous geological sequestration of carbon dioxide during power generation, organically combining geothermal power generation with carbon capture and storage (CCS) technology to help reduce carbon emissions. However, in the mining area, the waste heat from turbine exhaust is not fully utilized when generating electricity solely through supercritical carbon dioxide enhanced geothermal power generation systems (sCO2-EGS), resulting in low energy efficiency. Furthermore, the storage of carbon dioxide leads to a gradual decrease in the working fluid flow of sCO2-EGS. Moreover, electricity is characterized by its immediate availability, and the lack of supporting energy storage devices may lead to supply and demand imbalances, affecting normal production and causing economic losses. Summary of the Invention

[0004] The purpose of this invention is to provide a Carnot battery and carbon dioxide enhanced geothermal system for mining areas, which solves the problems of low energy utilization efficiency, reduced working fluid flow, and imbalance between power supply and demand in existing mining geothermal systems that rely solely on supercritical carbon dioxide enhanced geothermal power generation systems.

[0005] Another object of the present invention is to provide an operation method for a Carnot battery and carbon dioxide enhanced geothermal system for mining areas.

[0006] The technical solution adopted in this invention is a Carnot battery and carbon dioxide enhanced geothermal system for mining areas, including a sCO2-EGS subsystem. The sCO2-EGS subsystem is connected to a Carnot battery subsystem via pipelines. The Carnot battery subsystem is connected to a mine water waste heat utilization subsystem via pipelines. The sCO2-EGS subsystem is also connected to a gas waste heat utilization subsystem via pipelines. It also includes a power busbar. The sCO2-EGS subsystem, Carnot battery subsystem, mine water waste heat utilization subsystem, and gas waste heat utilization subsystem are all connected to the power busbar via conductors.

[0007] The invention is further characterized by: The sCO2-EGS subsystem includes a carbon dioxide production well, which is connected to a first heat exchanger via a pipeline. The outlet of the first heat exchanger is connected in sequence via a shaft to a high-pressure turbine, a low-pressure turbine, and a first generator. The first generator is connected to a power bus via a conductor. The subsystem also includes a second heat exchanger, whose inlet is connected to the exhaust port of the high-pressure turbine, and whose outlet is connected to the inlet of the low-pressure turbine. The exhaust port of the low-pressure turbine is connected to a Carnot battery subsystem, which is connected to a first gas compressor via a pipeline. The first gas compressor is connected to a carbon dioxide injection well via a pipeline.

[0008] The Carnot battery subsystem includes a heat pump circulation system, which includes a third heat exchanger. The inlet end of the condenser side of the third heat exchanger is connected to the exhaust port of the low-pressure turbine via a pipe, and the outlet end of the condenser side of the third heat exchanger is connected to the first gas compressor via a pipe. The evaporator side of the third heat exchanger is connected in sequence via pipes to the first compressor, the heat storage circulation system, and the first throttle valve. The outlet of the first throttle valve is connected to the third heat exchanger via a pipe to form a circulation loop. The first compressor is connected to the power bus via a wire.

[0009] The thermal storage circulation system includes a fourth heat exchanger. The inlet end of the condenser side of the fourth heat exchanger is connected to the first compressor through a pipe, and the outlet end of the condenser side of the fourth heat exchanger is connected to the first throttle valve through a pipe. The evaporator side of the fourth heat exchanger is connected in sequence through pipes to a first water pump, a high-temperature water tank, an organic Rankine circulation system, a low-temperature water tank, and a second water pump. The outlet end of the second water pump is connected to the fourth heat exchanger through a pipe to form a circulation loop.

[0010] The organic Rankine cycle system includes a fifth heat exchanger. The inlet end of the condenser side of the fifth heat exchanger is connected to a high-temperature water tank via a pipe, and the outlet end of the condenser side of the fifth heat exchanger is connected to a low-temperature water tank via a pipe. The evaporator side of the fifth heat exchanger is connected in sequence via pipes to a first turbine, a cooling water circulation system, a mine water waste heat utilization subsystem, and a working fluid pump. The working fluid pump is connected to the fifth heat exchanger via a pipe to form a circulation loop. The first turbine is connected to a second generator via a shaft, and the second generator is connected to the power bus via a conductor.

[0011] The cooling water circulation system includes a sixth heat exchanger. The inlet end of the condenser side of the sixth heat exchanger is connected to the first turbine through a pipe. The outlet end of the condenser side of the sixth heat exchanger is connected to the mine water waste heat utilization subsystem through a pipe. The evaporator side of the sixth heat exchanger is connected to the first cooling tower and the third water pump in sequence through pipes. The third water pump is connected to the sixth heat exchanger through a pipe to form a circulation loop.

[0012] The mine water waste heat utilization subsystem includes a seventh heat exchanger. The inlet end of the evaporation side of the seventh heat exchanger is connected to the sixth heat exchanger via a pipe, and the outlet end of the evaporation side of the seventh heat exchanger is connected to the working fluid pump via a pipe. The condenser side of the seventh heat exchanger is connected in sequence via a pipe to a second throttle valve, an eighth heat exchanger, and a second compressor. The second compressor is connected to the seventh heat exchanger via a pipe to form a circulation loop. The eighth heat exchanger is connected to a mine water tank via a pipe, and the mine water tank is connected to a fourth water pump via a pipe. The fourth water pump is connected to the eighth heat exchanger via a pipe to form a circulation loop. A water surface photovoltaic system is installed in the mine water tank, and the water surface photovoltaic system is connected to the power bus via a conductor.

[0013] The waste heat recovery subsystem includes a methane storage tank, which is connected to an internal combustion engine via a pipeline. The internal combustion engine is connected to a third generator via a shaft, and the third generator is connected to a power bus via a wire. The internal combustion engine is connected to a first heat exchanger and a second heat exchanger via pipelines. The second heat exchanger is connected to a waste heat boiler, a second turbine, and a second cooling tower via pipelines. The second turbine is connected to a fourth generator via a shaft, and the fourth generator is connected to a power bus via a wire. One flue gas outlet of the waste heat boiler is connected to a chimney via a pipeline. The other flue gas outlet of the waste heat boiler is connected to a carbon dioxide purifier and a second gas compressor via pipelines. The outlet of the second gas compressor is connected to the inlet of the first gas compressor.

[0014] Another technical solution adopted in this invention is a method for operating a Carnot battery and carbon dioxide-enhanced geothermal system for mining areas, comprising the following steps: Step 1: Set the power grid load G0, system load G, and water tank capacity V; Step 2: If G > G0, the sCO2-EGS and gas waste heat subsystem operate normally, the Carnot battery enters the charging state, the heat pump circulates to absorb and store heat, and the other circulation and mine water subsystems are shut down. Step 3: If G < G0, the Carnot battery enters the discharge state, the heat storage cycle releases heat to drive the organic Rankine cycle to generate electricity, and the mine water subsystem is activated to recover waste heat. Step 4: When the power grid load changes, adjust the system output by regulating the gas supply or sCO2 injection flow rate to maintain load balance.

[0015] Another feature of this invention is that: Step 2 is as follows: If the system load G is greater than the grid load G0, the sCO2-EGS subsystem and the gas waste heat utilization subsystem operate normally first; the Carnot battery subsystem enters the charging state, at which time the heat pump circulation system is turned on. The working fluid of the heat pump circulation system absorbs heat on the evaporation side through the third heat exchanger to become superheated steam, and then enters the first compressor to be heated and pressurized. The high-temperature and high-pressure gas transfers heat to the heat storage circulation system on the condensation side through the fourth heat exchanger, and then is throttled in the first throttle valve to complete the heat pump cycle; the fifth heat exchanger of the heat storage circulation system is turned off, and the other parts are turned on; the working fluid water of the heat storage circulation system enters the fourth heat exchanger after being pressurized by the second water pump from the low-temperature water tank, and absorbs the heat of the heat pump circulation working fluid through the fourth heat exchanger. The heated water is sent to the high-temperature water tank by the first water pump for storage, thus completing the heat storage system cycle; the organic Rankine cycle and cooling water cycle are both turned off, and the mine water waste heat utilization subsystem is turned off; Step 3 is as follows: If the system load G is less than the grid load G0, the sCO2-EGS subsystem and the gas waste heat utilization subsystem operate normally, and the Carnot battery subsystem enters the discharge state. At this time, the heat pump cycle is shut down, the fourth heat exchanger of the heat storage cycle is shut down, and the other parts are turned on. The working fluid water of the heat storage cycle enters the fifth heat exchanger from the high-temperature water tank, and releases heat to the working fluid of the organic Rankine cycle through the fifth heat exchanger. The cooled water enters the low-temperature water tank for storage, thus completing the heat storage cycle. The organic Rankine cycle and the cooling water cycle are both turned on. The working fluid of the organic Rankine cycle absorbs the heat released by the working fluid water of the heat storage cycle through the fifth heat exchanger on the evaporation side. The heated working fluid enters the first turbine, which drives the second generator to generate electricity. The working fluid after doing work flows through the sixth heat exchanger to release heat to the working fluid water of the cooling water cycle. The low-temperature and low-pressure working fluid then flows through the seventh heat exchanger to absorb the heat released by the working fluid of the high-temperature heat pump cycle. The working fluid, after being pressurized by the working fluid pump, enters the fifth heat exchanger, thus completing the organic Rankine cycle. The working fluid of the cooling water circulation absorbs the heat released by the working fluid of the organic Rankine cycle through the sixth heat exchanger. The heated water enters the first cooling tower for cooling, and the cooled water is sent to the sixth heat exchanger by the third water pump, completing the cooling water circulation. The mine water waste heat utilization subsystem is activated, and the working fluid of the high-temperature heat pump cycle releases heat to the working fluid of the organic Rankine cycle through the seventh heat exchanger. The cooled working fluid enters the second throttling valve for throttling, and the throttled working fluid enters the eighth heat exchanger to absorb the heat released by the working fluid of the mine water circulation. The heated working fluid enters the second compressor for further heating and pressurization. The high-temperature and high-pressure gas enters the seventh heat exchanger, completing the high-temperature heat pump cycle. The working fluid of the mine water circulation is sent to the eighth heat exchanger by the fourth water pump to release heat to the working fluid of the high-temperature heat pump cycle. The cooled working fluid returns to the mine water pool for reheating, thus completing the mine water circulation. Step 4 is as follows: The grid load becomes G0′, and the system load is G′. Based on step 2, if the system load G′ is still greater than the grid load G0′, and the Carnot battery is fully charged when the high-temperature water tank capacity V reaches its maximum value, the load of the gas waste heat utilization subsystem is reduced first, and the gas power generation output is reduced by reducing the amount of methane supplied. The amount of high-temperature flue gas is thus reduced, and the high-temperature flue gas flows through the first heat exchanger and the second heat exchanger in sequence, and enters the waste heat boiler, thereby reducing the output of the waste heat boiler and the amount of steam entering the second turbine, thereby reducing the output of the fourth generator. Based on step 2, if the system load G′ is less than the grid load G0′, the system executes step 3. If the system load G′ is still less than the grid load G0′, the system executes step 3 again. Based on step 3, if the system load G′ is greater than the grid load G0′, the system executes step 2. When the grid load becomes G0′′, the system load is G′′. If the system load G′′ is still greater than the grid load G0′′, the sCO2-EGS subsystem enters a low-load operation state. By adjusting the speed of the first gas compressor, the mass flow rate of sCO2 injected into the formation is reduced, thereby reducing the output of the first generator. At this time, the total power generation output of the system reaches the minimum value. If the system load G′ is less than the grid load G0′, the system executes step 3.

[0016] The beneficial effects of this invention are: This invention provides a Carnot battery and carbon dioxide-enhanced geothermal system and method for mining areas. The Carnot battery stores electrical energy as heat, flexibly adjusting the balance between the power generation and load sides. In the heat pump cycle used during charging, the evaporator absorbs the waste heat from the carbon dioxide after work is done. In the organic Rankine cycle used during discharging, a high-temperature heat pump recovers the low-temperature waste heat from the mine water, effectively improving the system's waste heat utilization rate and the Carnot battery's round-trip efficiency, reducing energy consumption. The system also utilizes the heat from the high-temperature flue gas generated after coal mine gas power generation. The high-temperature flue gas first heats the carbon dioxide output from the production well in the sCO2-EGS system, increasing the inlet temperature of the high-pressure turbine; then it heats the carbon dioxide intake gas of the low-pressure turbine, further improving power generation efficiency; finally, the still relatively high-temperature flue gas is sent to the waste heat boiler to generate steam for further power generation, maximizing energy utilization. The system couples geothermal power generation with CCS technology, making carbon dioxide both the working fluid for geothermal power generation and the storage medium for CCS. During the cycle, some carbon dioxide is converted into stable carbonate minerals through mineralization and stored in the fracture network of hot dry rocks. At the same time, carbon dioxide from high-temperature flue gas is introduced into the cycle for supplementary gas supply, thus realizing a complete process chain of "emission-capture-power generation-storage" and promoting the sustainable development of carbon sequestration. Attached Figure Description

[0017] Figure 1This is a schematic diagram of the structure of the Carnot battery and carbon dioxide enhanced geothermal system for mining areas according to the present invention; Figure 2 This is a schematic flowchart illustrating the operation method of the Carnot battery and carbon dioxide enhanced geothermal system for mining areas according to the present invention.

[0018] In the diagram, 1. Carbon dioxide production well, 2. High-pressure turbine, 3. Low-pressure turbine, 4. First generator, 5. First gas compressor, 6. Carbon dioxide injection well, 7. First compressor, 8. First throttle valve, 9. First water pump, 10. High-temperature water tank, 11. Low-temperature water tank, 12. Second water pump, 13. First turbine, 14. Second generator, 15. Working fluid pump, 16. First cooling tower, 17. Third water pump, 18. Methane storage tank, 19. Internal combustion engine, 20. Third generator, 21. Waste heat boiler. 22. Second turbine, 23. Fourth generator, 24. Second cooling tower, 25. Carbon dioxide purifier, 26. Second gas compressor, 27. Chimney, 28. Second throttle valve, 29. Second compressor, 30. Mine water tank, 31. Surface photovoltaic, 32. Fourth water pump, 33. Power bus, 34. First heat exchanger, 35. Second heat exchanger, 36. Third heat exchanger, 37. Fourth heat exchanger, 38. Fifth heat exchanger, 39. Sixth heat exchanger, 40. Seventh heat exchanger, 41. Eighth heat exchanger. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0020] The Carnot battery and carbon dioxide-enhanced geothermal system for mining areas provided by this invention, such as Figure 1As shown, the system includes an sCO2-EGS subsystem, which is connected to a Carnot battery subsystem via pipelines. The Carnot battery subsystem is connected to a mine water waste heat utilization subsystem via pipelines. The sCO2-EGS subsystem is also connected to a gas waste heat utilization subsystem via pipelines. It also includes a power busbar 33. The sCO2-EGS subsystem, Carnot battery subsystem, mine water waste heat utilization subsystem, and gas waste heat utilization subsystem are all connected to the power busbar 33 via conductors. The sCO2-EGS subsystem includes a carbon dioxide production well 1, which is connected to a first heat exchanger 34 via pipelines. The outlet of the first heat exchanger 34 is sequentially connected to a high-pressure turbine 2, a low-pressure turbine 3, and a... The system includes a generator 4, which is connected to a power bus 33 via a conductor; it also includes a second heat exchanger 35, whose inlet is connected to the exhaust port of a high-pressure turbine 2, and whose outlet is connected to the inlet of a low-pressure turbine 3. The exhaust port of the low-pressure turbine 3 is connected to a Carnot battery subsystem, which is connected to a first gas compressor 5 via a pipeline. The first gas compressor 5 is connected to a carbon dioxide injection well 6 via a pipeline. The Carnot battery subsystem includes a heat pump circulation system, which includes a third heat exchanger 36. The inlet of the condenser side of the third heat exchanger 36 is connected to the exhaust port of the low-pressure turbine 3 via a pipeline, and the outlet of the condenser side of the third heat exchanger 36 is connected to the exhaust port of the first gas compressor 2 via a pipeline. The compressor 5 is connected, and the evaporator side of the third heat exchanger 36 is sequentially connected to the first compressor 7, the heat storage circulation system, and the first throttle valve 8 via pipes. The outlet of the first throttle valve 8 is connected to the third heat exchanger 36 via a pipe to form a circulation loop. The outlet end of the condenser side of the third heat exchanger 36 is connected to the first gas compressor 5 via a pipe. The first compressor 7 is connected to the power bus 33 via a wire. The heat storage circulation system includes a fourth heat exchanger 37. The inlet end of the condenser side of the fourth heat exchanger 37 is connected to the first compressor 7 via a pipe. The outlet end of the condenser side of the fourth heat exchanger 37 is connected to the first throttle valve 8 via a pipe. The evaporator side of the fourth heat exchanger 37 is sequentially connected to the first water pump 9, the high-temperature water tank 10, and the organic Rankine circulation system via pipes. The low-temperature water tank 11 is connected to the second water pump 12, and the outlet end of the second water pump 12 is connected to the fourth heat exchanger 37 through a pipe to form a circulation loop; the organic Rankine cycle system includes a fifth heat exchanger 38, the inlet end of the condenser side of the fifth heat exchanger 38 is connected to the high-temperature water tank 10 through a pipe, the outlet end of the condenser side of the fifth heat exchanger 38 is connected to the low-temperature water tank 11 through a pipe, the evaporator side of the fifth heat exchanger 38 is connected in sequence to the first turbine 13, the cooling water circulation system, the mine water waste heat utilization subsystem and the working fluid pump 15 through pipes, the working fluid pump 15 is connected to the fifth heat exchanger 38 through a pipe to form a circulation loop, the first turbine 13 is connected to the second generator 14 through a shaft, and the second generator 14 is connected to the power bus 33 through a wire;The cooling water circulation system includes a sixth heat exchanger 39. The inlet end of the condenser side of the sixth heat exchanger 39 is connected to the first turbine 13 via a pipe, and the outlet end of the condenser side of the sixth heat exchanger 39 is connected to the mine water waste heat utilization subsystem via a pipe. The evaporator side of the sixth heat exchanger 39 is connected in sequence to the first cooling tower 16 and the third water pump 17 via pipes. The third water pump 17 is connected to the sixth heat exchanger 39 via a pipe to form a circulation loop. The mine water waste heat utilization subsystem includes a seventh heat exchanger 40. The evaporator side of the seventh heat exchanger 40... The inlet end of the seventh heat exchanger 40 is connected to the sixth heat exchanger 39 via a pipe. The outlet end of the evaporation side of the seventh heat exchanger 40 is connected to the working fluid pump 15 via a pipe. The condenser side of the seventh heat exchanger 40 is connected in sequence to the second throttle valve 28, the eighth heat exchanger 41, and the second compressor 29 via pipes. The second compressor 29 is connected to the seventh heat exchanger 40 via a pipe to form a circulation loop. The eighth heat exchanger 41 is connected to the mine water tank 30 via a pipe. The mine water tank 30 is connected to the fourth water pump 32 via a pipe. The fourth water pump 32 is connected to... The eighth heat exchanger 41 is connected to form a circulation loop. A water surface photovoltaic 31 is installed in the mine water pool 30, and the water surface photovoltaic 31 is connected to the power bus 33 through a conductor. The gas waste heat utilization subsystem includes a methane storage tank 18, which is connected to an internal combustion engine 19 through a pipeline. The internal combustion engine 19 is connected to a third generator 20 through a shaft, and the third generator 20 is connected to the power bus 33 through a conductor. The internal combustion engine 19 is connected to the first heat exchanger 34 and the second heat exchanger 35 in sequence through pipelines. A waste heat boiler 21, a second turbine 22, and a second cooling tower 24 are connected sequentially via pipelines. A fourth generator 23 is connected to the second turbine 22 via a shaft. The fourth generator 23 is connected to the power busbar 33 via conductors. One flue gas outlet of the waste heat boiler 21 is connected to a chimney 27 via a pipeline. The other flue gas outlet of the waste heat boiler 21 is connected sequentially to a carbon dioxide purifier 25 and a second gas compressor 26 via pipelines. The outlet of the second gas compressor 26 is connected to the inlet of the first gas compressor 5. This system fully utilizes waste heat resources such as mine gas power generation waste heat and mine water waste heat, and enables the on-site development of renewable energy sources such as geothermal energy and solar energy. Combined with a low-temperature Carnot battery, it allows for flexible adjustment of the power load, effectively solving problems such as high emissions of pollutants and greenhouse gases, insufficient utilization of waste heat resources, and poor grid flexibility in the mining area, significantly improving economic efficiency.

[0021] Example 1 The Carnot battery and carbon dioxide-enhanced geothermal system proposed in this embodiment for mining areas, such as Figure 1As shown, the system includes an sCO2-EGS subsystem, which is connected to a Carnot battery subsystem via a pipeline. The Carnot battery subsystem is connected to a mine water waste heat utilization subsystem via a pipeline. The sCO2-EGS subsystem is also connected to a gas waste heat utilization subsystem via a pipeline. The system also includes a power bus 33. The sCO2-EGS subsystem, the Carnot battery subsystem, the mine water waste heat utilization subsystem, and the gas waste heat utilization subsystem are all connected to the power bus 33 via conductors.

[0022] Example 2 The Carnot battery and carbon dioxide-enhanced geothermal system proposed in this embodiment for mining areas, such as Figure 1 As shown, the system includes an sCO2-EGS subsystem, which is connected to a Carnot battery subsystem via pipelines. The Carnot battery subsystem is connected to a mine water waste heat utilization subsystem via pipelines. The sCO2-EGS subsystem is also connected to a gas waste heat utilization subsystem via pipelines. It also includes a power busbar 33. The sCO2-EGS subsystem, Carnot battery subsystem, mine water waste heat utilization subsystem, and gas waste heat utilization subsystem are all connected to the power busbar 33 via conductors. The sCO2-EGS subsystem includes a carbon dioxide production well 1, which is connected to a gas waste heat utilization subsystem via pipelines. The system includes a first heat exchanger 34, whose outlet is connected in sequence to a high-pressure turbine 2, a low-pressure turbine 3, and a first generator 4 via a shaft. The first generator 4 is connected to a power bus 33 via a conductor. The system also includes a second heat exchanger 35, whose inlet is connected to the exhaust port of the high-pressure turbine 2, and whose outlet is connected to the inlet of the low-pressure turbine 3. The exhaust port of the low-pressure turbine 3 is connected to a Carnot battery subsystem. The Carnot battery subsystem is connected to a first gas compressor 5 via a pipeline, and the first gas compressor 5 is connected to a carbon dioxide injection well 6 via a pipeline.

[0023] Example 3 The Carnot battery and carbon dioxide-enhanced geothermal system proposed in this embodiment for mining areas, such as Figure 1As shown, the system includes an sCO2-EGS subsystem, which is connected to a Carnot battery subsystem via pipelines. The Carnot battery subsystem is connected to a mine water waste heat utilization subsystem via pipelines. The sCO2-EGS subsystem is also connected to a gas waste heat utilization subsystem via pipelines. It also includes a power busbar 33. The sCO2-EGS subsystem, Carnot battery subsystem, mine water waste heat utilization subsystem, and gas waste heat utilization subsystem are all connected to the power busbar 33 via conductors. The sCO2-EGS subsystem includes a carbon dioxide production well 1, which is connected to a first heat exchanger 34 via pipelines. The outlet of the first heat exchanger 34 is sequentially connected to a high-pressure turbine 2, a low-pressure turbine 3, and a... The system includes a generator 4, which is connected to a power bus 33 via a conductor; it also includes a second heat exchanger 35, whose inlet is connected to the exhaust port of a high-pressure turbine 2, and whose outlet is connected to the inlet of a low-pressure turbine 3. The exhaust port of the low-pressure turbine 3 is connected to a Carnot battery subsystem, which is connected to a first gas compressor 5 via a pipeline. The first gas compressor 5 is connected to a carbon dioxide injection well 6 via a pipeline. The Carnot battery subsystem includes a heat pump circulation system, which includes a third heat exchanger 36. The inlet of the condenser side of the third heat exchanger 36 is connected to the exhaust port of the low-pressure turbine 3 via a pipeline, and the outlet of the condenser side of the third heat exchanger 36 is connected to the exhaust port of the first gas compressor 2 via a pipeline. The compressor 5 is connected, and the evaporator side of the third heat exchanger 36 is sequentially connected to the first compressor 7, the heat storage circulation system, and the first throttle valve 8 via pipes. The outlet of the first throttle valve 8 is connected to the third heat exchanger 36 via a pipe to form a circulation loop. The outlet end of the condenser side of the third heat exchanger 36 is connected to the first gas compressor 5 via a pipe. The first compressor 7 is connected to the power bus 33 via a wire. The heat storage circulation system includes a fourth heat exchanger 37. The inlet end of the condenser side of the fourth heat exchanger 37 is connected to the first compressor 7 via a pipe. The outlet end of the condenser side of the fourth heat exchanger 37 is connected to the first throttle valve 8 via a pipe. The evaporator side of the fourth heat exchanger 37 is sequentially connected to the first water pump 9, the high-temperature water tank 10, and the organic Rankine circulation system via pipes. The low-temperature water tank 11 is connected to the second water pump 12, and the outlet end of the second water pump 12 is connected to the fourth heat exchanger 37 through a pipe to form a circulation loop; the organic Rankine cycle system includes a fifth heat exchanger 38, the inlet end of the condenser side of the fifth heat exchanger 38 is connected to the high-temperature water tank 10 through a pipe, the outlet end of the condenser side of the fifth heat exchanger 38 is connected to the low-temperature water tank 11 through a pipe, the evaporator side of the fifth heat exchanger 38 is connected in sequence to the first turbine 13, the cooling water circulation system, the mine water waste heat utilization subsystem and the working fluid pump 15 through pipes, the working fluid pump 15 is connected to the fifth heat exchanger 38 through a pipe to form a circulation loop, the first turbine 13 is connected to the second generator 14 through a shaft, and the second generator 14 is connected to the power bus 33 through a wire;The cooling water circulation system includes a sixth heat exchanger 39. The inlet end of the condenser side of the sixth heat exchanger 39 is connected to the first turbine 13 via a pipe, and the outlet end of the condenser side of the sixth heat exchanger 39 is connected to the mine water waste heat utilization subsystem via a pipe. The evaporator side of the sixth heat exchanger 39 is sequentially connected to the first cooling tower 16 and the third water pump 17 via pipes. The third water pump 17 is connected to the sixth heat exchanger 39 via a pipe to form a circulation loop.

[0024] Example 4 The Carnot battery and carbon dioxide-enhanced geothermal system proposed in this embodiment for mining areas, such as Figure 1As shown, the system includes an sCO2-EGS subsystem, which is connected to a Carnot battery subsystem via pipelines. The Carnot battery subsystem is connected to a mine water waste heat utilization subsystem via pipelines. The sCO2-EGS subsystem is also connected to a gas waste heat utilization subsystem via pipelines. It also includes a power busbar 33. The sCO2-EGS subsystem, Carnot battery subsystem, mine water waste heat utilization subsystem, and gas waste heat utilization subsystem are all connected to the power busbar 33 via conductors. The sCO2-EGS subsystem includes a carbon dioxide production well 1, which is connected to a first heat exchanger 34 via pipelines. The outlet of the first heat exchanger 34 is sequentially connected to a high-pressure turbine 2, a low-pressure turbine 3, and a... The system includes a generator 4, which is connected to a power bus 33 via a conductor; it also includes a second heat exchanger 35, whose inlet is connected to the exhaust port of a high-pressure turbine 2, and whose outlet is connected to the inlet of a low-pressure turbine 3. The exhaust port of the low-pressure turbine 3 is connected to a Carnot battery subsystem, which is connected to a first gas compressor 5 via a pipeline. The first gas compressor 5 is connected to a carbon dioxide injection well 6 via a pipeline. The Carnot battery subsystem includes a heat pump circulation system, which includes a third heat exchanger 36. The inlet of the condenser side of the third heat exchanger 36 is connected to the exhaust port of the low-pressure turbine 3 via a pipeline, and the outlet of the condenser side of the third heat exchanger 36 is connected to the exhaust port of the first gas compressor 2 via a pipeline. The compressor 5 is connected, and the evaporator side of the third heat exchanger 36 is sequentially connected to the first compressor 7, the heat storage circulation system, and the first throttle valve 8 via pipes. The outlet of the first throttle valve 8 is connected to the third heat exchanger 36 via a pipe to form a circulation loop. The outlet end of the condenser side of the third heat exchanger 36 is connected to the first gas compressor 5 via a pipe. The first compressor 7 is connected to the power bus 33 via a wire. The heat storage circulation system includes a fourth heat exchanger 37. The inlet end of the condenser side of the fourth heat exchanger 37 is connected to the first compressor 7 via a pipe. The outlet end of the condenser side of the fourth heat exchanger 37 is connected to the first throttle valve 8 via a pipe. The evaporator side of the fourth heat exchanger 37 is sequentially connected to the first water pump 9, the high-temperature water tank 10, and the organic Rankine circulation system via pipes. The low-temperature water tank 11 is connected to the second water pump 12, and the outlet end of the second water pump 12 is connected to the fourth heat exchanger 37 through a pipe to form a circulation loop; the organic Rankine cycle system includes a fifth heat exchanger 38, the inlet end of the condenser side of the fifth heat exchanger 38 is connected to the high-temperature water tank 10 through a pipe, the outlet end of the condenser side of the fifth heat exchanger 38 is connected to the low-temperature water tank 11 through a pipe, the evaporator side of the fifth heat exchanger 38 is connected in sequence to the first turbine 13, the cooling water circulation system, the mine water waste heat utilization subsystem and the working fluid pump 15 through pipes, the working fluid pump 15 is connected to the fifth heat exchanger 38 through a pipe to form a circulation loop, the first turbine 13 is connected to the second generator 14 through a shaft, and the second generator 14 is connected to the power bus 33 through a wire;The cooling water circulation system includes a sixth heat exchanger 39. The inlet end of the condenser side of the sixth heat exchanger 39 is connected to the first turbine 13 via a pipe, and the outlet end of the condenser side of the sixth heat exchanger 39 is connected to the mine water waste heat utilization subsystem via a pipe. The evaporator side of the sixth heat exchanger 39 is connected in sequence to the first cooling tower 16 and the third water pump 17 via pipes. The third water pump 17 is connected to the sixth heat exchanger 39 via a pipe to form a circulation loop. The mine water waste heat utilization subsystem includes a seventh heat exchanger 40. The inlet end of the evaporator side of the seventh heat exchanger 40 is connected to the sixth heat exchanger 39 via a pipe, and the evaporator side of the seventh heat exchanger 40... The outlet end of the generator is connected to the working fluid pump 15 via a pipe. The condenser side of the seventh heat exchanger 40 is sequentially connected to the second throttle valve 28, the eighth heat exchanger 41, and the second compressor 29 via pipes. The second compressor 29 is connected to the seventh heat exchanger 40 via a pipe to form a circulation loop. The eighth heat exchanger 41 is connected to a mine water tank 30 via a pipe. The mine water tank 30 is connected to a fourth water pump 32 via a pipe. The fourth water pump 32 is connected to the eighth heat exchanger 41 via a pipe to form a circulation loop. A surface photovoltaic system 31 is installed inside the mine water tank 30 and is connected to the power busbar 33 via a conductor.

[0025] Example 5 The Carnot battery and carbon dioxide-enhanced geothermal system proposed in this embodiment for mining areas, such as Figure 1As shown, the system includes an sCO2-EGS subsystem, which is connected to a Carnot battery subsystem via pipelines. The Carnot battery subsystem is connected to a mine water waste heat utilization subsystem via pipelines. The sCO2-EGS subsystem is also connected to a gas waste heat utilization subsystem via pipelines. It also includes a power busbar 33. The sCO2-EGS subsystem, Carnot battery subsystem, mine water waste heat utilization subsystem, and gas waste heat utilization subsystem are all connected to the power busbar 33 via conductors. The sCO2-EGS subsystem includes a carbon dioxide production well 1, which is connected to a first heat exchanger 34 via pipelines. The outlet of the first heat exchanger 34 is sequentially connected to a high-pressure turbine 2, a low-pressure turbine 3, and a... The system includes a generator 4, which is connected to a power bus 33 via a conductor; it also includes a second heat exchanger 35, whose inlet is connected to the exhaust port of a high-pressure turbine 2, and whose outlet is connected to the inlet of a low-pressure turbine 3. The exhaust port of the low-pressure turbine 3 is connected to a Carnot battery subsystem, which is connected to a first gas compressor 5 via a pipeline. The first gas compressor 5 is connected to a carbon dioxide injection well 6 via a pipeline. The Carnot battery subsystem includes a heat pump circulation system, which includes a third heat exchanger 36. The inlet of the condenser side of the third heat exchanger 36 is connected to the exhaust port of the low-pressure turbine 3 via a pipeline, and the outlet of the condenser side of the third heat exchanger 36 is connected to the exhaust port of the first gas compressor 2 via a pipeline. The compressor 5 is connected, and the evaporator side of the third heat exchanger 36 is sequentially connected to the first compressor 7, the heat storage circulation system, and the first throttle valve 8 via pipes. The outlet of the first throttle valve 8 is connected to the third heat exchanger 36 via a pipe to form a circulation loop. The outlet end of the condenser side of the third heat exchanger 36 is connected to the first gas compressor 5 via a pipe. The first compressor 7 is connected to the power bus 33 via a wire. The heat storage circulation system includes a fourth heat exchanger 37. The inlet end of the condenser side of the fourth heat exchanger 37 is connected to the first compressor 7 via a pipe. The outlet end of the condenser side of the fourth heat exchanger 37 is connected to the first throttle valve 8 via a pipe. The evaporator side of the fourth heat exchanger 37 is sequentially connected to the first water pump 9, the high-temperature water tank 10, and the organic Rankine circulation system via pipes. The low-temperature water tank 11 is connected to the second water pump 12, and the outlet end of the second water pump 12 is connected to the fourth heat exchanger 37 through a pipe to form a circulation loop; the organic Rankine cycle system includes a fifth heat exchanger 38, the inlet end of the condenser side of the fifth heat exchanger 38 is connected to the high-temperature water tank 10 through a pipe, the outlet end of the condenser side of the fifth heat exchanger 38 is connected to the low-temperature water tank 11 through a pipe, the evaporator side of the fifth heat exchanger 38 is connected in sequence to the first turbine 13, the cooling water circulation system, the mine water waste heat utilization subsystem and the working fluid pump 15 through pipes, the working fluid pump 15 is connected to the fifth heat exchanger 38 through a pipe to form a circulation loop, the first turbine 13 is connected to the second generator 14 through a shaft, and the second generator 14 is connected to the power bus 33 through a wire;The cooling water circulation system includes a sixth heat exchanger 39. The inlet end of the condenser side of the sixth heat exchanger 39 is connected to the first turbine 13 via a pipe, and the outlet end of the condenser side of the sixth heat exchanger 39 is connected to the mine water waste heat utilization subsystem via a pipe. The evaporator side of the sixth heat exchanger 39 is sequentially connected to the first cooling tower 16 and the third water pump 17 via pipes. The third water pump 17 is connected to the sixth heat exchanger 39 via a pipe to form a circulation loop. The mine water waste heat utilization subsystem includes a seventh heat exchanger 40. The evaporator side of the seventh heat exchanger 40... The inlet end is connected to the sixth heat exchanger 39 via a pipe. The outlet end of the evaporation side of the seventh heat exchanger 40 is connected to the working fluid pump 15 via a pipe. The condenser side of the seventh heat exchanger 40 is connected in sequence to the second throttle valve 28, the eighth heat exchanger 41, and the second compressor 29 via pipes. The second compressor 29 is connected to the seventh heat exchanger 40 via a pipe to form a circulation loop. The eighth heat exchanger 41 is connected to the mine water tank 30 via a pipe. The mine water tank 30 is connected to the fourth water pump 32 via a pipe. The fourth water pump 32 is connected to the... Eight heat exchangers 41 are connected to form a circulation loop. A surface photovoltaic (PV) system 31 is installed in the mine water tank 30 and connected to the power bus 33 via wires. The gas waste heat utilization subsystem includes a methane storage tank 18, which is connected to an internal combustion engine 19 via a pipeline. The internal combustion engine 19 is connected to a third generator 20 via a shaft and connected to the power bus 33 via wires. The internal combustion engine 19 is connected to the first heat exchanger 34 and the second heat exchanger 35 via pipelines. The second heat exchanger 35 is connected to... A waste heat boiler 21, a second turbine 22, and a second cooling tower 24 are connected in sequence via pipes. A fourth generator 23 is connected to the second turbine 22 via a shaft. The fourth generator 23 is connected to the power busbar 33 via wires. One flue gas outlet of the waste heat boiler 21 is connected to a chimney 27 via a pipe. The other flue gas outlet of the waste heat boiler 21 is connected in sequence via pipes to a carbon dioxide purifier 25 and a second gas compressor 26. The outlet of the second gas compressor 26 is connected to the inlet of the first gas compressor 5.

[0026] Example 6 The operation method of the Carnot battery and carbon dioxide enhanced geothermal system for mining areas proposed in this embodiment is based on the above-mentioned Carnot battery and carbon dioxide enhanced geothermal system for mining areas, such as... Figure 2 As shown, it includes the following steps: Step 1: Set the power grid load G0, system load G, and water tank capacity V; Step 2: If G > G0, the sCO2-EGS and gas waste heat subsystem operate normally, the Carnot battery enters the charging state, the heat pump circulates to absorb and store heat, and the other circulation and mine water subsystems are shut down. Step 2 is as follows: If the system load G is greater than the grid load G0, the sCO2-EGS subsystem and the gas waste heat utilization subsystem operate normally first; the Carnot battery subsystem enters the charging state, at which time the heat pump circulation system is turned on. The working fluid of the heat pump circulation system absorbs heat on the evaporation side through the third heat exchanger to become superheated steam, and then enters the first compressor to be heated and pressurized. The high-temperature and high-pressure gas transfers heat to the heat storage circulation system on the condensation side through the fourth heat exchanger, and then is throttled in the first throttle valve to complete the heat pump cycle; the fifth heat exchanger of the heat storage circulation system is turned off, and the other parts are turned on; the working fluid water of the heat storage circulation system enters the fourth heat exchanger after being pressurized by the second water pump from the low-temperature water tank, and absorbs the heat of the heat pump circulation working fluid through the fourth heat exchanger. The heated water is sent to the high-temperature water tank by the first water pump for storage, thus completing the heat storage system cycle; the organic Rankine cycle and cooling water cycle are both turned off, and the mine water waste heat utilization subsystem is turned off; Step 3: If G < G0, the Carnot battery enters the discharge state, the heat storage cycle releases heat to drive the organic Rankine cycle to generate electricity, and the mine water subsystem is activated to recover waste heat. Step 3 is as follows: If the system load G is less than the grid load G0, the sCO2-EGS subsystem and the gas waste heat utilization subsystem operate normally, and the Carnot battery subsystem enters the discharge state. At this time, the heat pump cycle is shut down, the fourth heat exchanger of the heat storage cycle is shut down, and the other parts are turned on. The working fluid water of the heat storage cycle enters the fifth heat exchanger from the high-temperature water tank, and releases heat to the working fluid of the organic Rankine cycle through the fifth heat exchanger. The cooled water enters the low-temperature water tank for storage, thus completing the heat storage cycle. The organic Rankine cycle and the cooling water cycle are both turned on. The working fluid of the organic Rankine cycle absorbs the heat released by the working fluid water of the heat storage cycle through the fifth heat exchanger on the evaporation side. The heated working fluid enters the first turbine, which drives the second generator to generate electricity. The working fluid after doing work flows through the condenser to release heat to the working fluid water of the cooling water cycle. The low-temperature and low-pressure working fluid then flows through the sixth heat exchanger to absorb the heat released by the working fluid of the high-temperature heat pump cycle. The working fluid, pressurized by the working fluid pump, enters the fifth heat exchanger, thus completing the organic Rankine cycle. The working fluid in the cooling water circulation absorbs heat released by the working fluid in the organic Rankine cycle through the condenser. The heated water then enters the first cooling tower for cooling, and the cooled water is pumped back to the condenser by the third water pump, completing the cooling water circulation. The mine water waste heat utilization subsystem is activated. The working fluid in the high-temperature heat pump cycle releases heat to the working fluid in the organic Rankine cycle through the sixth heat exchanger. The cooled working fluid enters the second throttling valve for throttling, and then enters the seventh heat exchanger to absorb heat released by the working fluid in the mine water circulation. The heated working fluid enters the second compressor for further heating and pressurization. The high-temperature, high-pressure gas enters the sixth heat exchanger, completing the high-temperature heat pump cycle. The working fluid in the mine water circulation is pumped to the seventh heat exchanger by the fourth water pump, releasing heat to the working fluid in the high-temperature heat pump cycle. The cooled working fluid returns to the mine water tank for reheating, thus completing the mine water circulation. Step 4: When the power grid load changes, adjust the system output by regulating the gas supply or sCO2 injection flow rate to maintain load balance; Step 4 is as follows: The grid load becomes G0′, and the system load is G′. Based on step 2, if the system load G′ is still greater than the grid load G0′, and the Carnot battery is fully charged when the high-temperature water tank capacity V reaches its maximum value, the load of the gas waste heat utilization subsystem is reduced first, and the gas power generation output is reduced by reducing the amount of methane supplied. The amount of high-temperature flue gas is thus reduced, and the high-temperature flue gas flows through the first heat exchanger and the second heat exchanger in sequence, and enters the waste heat boiler, thereby reducing the output of the waste heat boiler and the amount of steam entering the second turbine, thereby reducing the output of the fourth generator. Based on step 2, if the system load G′ is less than the grid load G0′, the system executes step 3. If the system load G′ is still less than the grid load G0′, the system executes step 3 again. Based on step 3, if the system load G′ is greater than the grid load G0′, the system executes step 2. When the grid load becomes G0′′, the system load is G′′. If the system load G′′ is still greater than the grid load G0′′, the sCO2-EGS subsystem enters a low-load operation state. By adjusting the speed of the first gas compressor, the mass flow rate of sCO2 injected into the formation is reduced, thereby reducing the output of the first generator. At this time, the total power generation output of the system reaches the minimum value. If the system load G′ is less than the grid load G0′, the system executes step 3.

[0027] Example 7 The operation method of the Carnot battery and carbon dioxide enhanced geothermal system for mining areas proposed in this embodiment is based on the above-mentioned Carnot battery and carbon dioxide enhanced geothermal system for mining areas, such as... Figure 2 As shown, the specific steps are as follows: Step 1: Set the power grid load G0, system load G, and water tank capacity V.

[0028] Step 2: If the system load G is greater than the grid load G0, the sCO2-EGS subsystem and the gas waste heat utilization subsystem will operate normally first. In the sCO2-EGS subsystem, the outlet temperature of carbon dioxide production well 1 is 150℃, the inlet temperature of high pressure turbine 2 is 250℃, the outlet temperature of high pressure turbine 2 is 120℃, the inlet temperature of low pressure turbine 3 is 200℃, the outlet temperature of low pressure turbine 3 is 70℃, the inlet temperature of carbon dioxide injection well 6 is 40℃, the initial temperature of the high-temperature flue gas in the gas waste heat utilization subsystem is 500℃, the flue gas temperature after passing through the first heat exchanger 34 is 400℃, and the flue gas temperature after passing through the second heat exchanger 35 is 320℃. At this point, the Carnot battery subsystem enters the charging state, and the heat pump cycle starts. The heat pump cycle uses R365mfc pentafluorobutane as the working fluid, which absorbs heat on the evaporation side of the heat pump cycle through the third heat exchanger 36 to become superheated steam. The temperature of R365mfc entering the third heat exchanger 36 is 35°C, and the outlet temperature is 60°C. The R365mfc gas then enters the first compressor 7 for heating and pressurization, reaching a temperature of 120°C. The high-temperature, high-pressure R365mfc gas transfers heat to the heat storage cycle via the fourth heat exchanger 37 on the condenser side, reducing its temperature to 80°C. Subsequently, the R365mfc is throttled in the first throttle valve 8, completing the heat pump cycle. The fifth heat exchanger 38 of the heat storage cycle is closed, while other parts are open. The high-temperature water tank 10 is set to 100°C, and the low-temperature water tank 11 is set to 60°C. The working fluid water of the heat storage cycle enters the fourth heat exchanger 37 after being pressurized by the second water pump 12 from the low-temperature water tank 11. The fourth heat exchanger 37 absorbs heat from the heat pump cycle working fluid R365mfc, resulting in a water temperature of 65°C entering the fourth heat exchanger 37 and an outlet temperature of 95°C. The heated water is then pumped by the first water pump 9 into the high-temperature water tank 10 for storage, thus completing the heat storage cycle. The organic Rankine cycle, cooling water cycle, and mine water waste heat utilization subsystem are all closed. Step 3: If the system load G is less than the grid load G0, the sCO2-EGS subsystem and the waste gas heat utilization subsystem operate normally, and the Carnot battery subsystem enters the discharge state. At this time, the heat pump cycle is shut down, the fourth heat exchanger 37 of the heat storage cycle is shut down, and the other parts are turned on. The working fluid water of the heat storage cycle enters the fifth heat exchanger 38 from the high-temperature water tank 10, and releases heat to the organic Rankine cycle through the fifth heat exchanger 38. The cooled water enters the low-temperature water tank 11 for storage, thus completing the heat storage cycle. The organic Rankine cycle and the cooling water cycle are both turned on. The organic Rankine cycle also uses R365mfc as the working fluid, and absorbs the heat released by the working fluid water of the heat storage cycle through the fifth heat exchanger 38 on the evaporation side. The temperature entering the fifth heat exchanger 38 is 50°C, and the outlet temperature is 90°C. The heated R365mfc enters the first turbine 13, which drives the second generator 14 to generate electricity. After doing work, the temperature of the R365mfc drops to 45°C. Then, the R365mfc flows through the sixth heat exchanger 39 to circulate heat into the cooling water, releasing heat and lowering its temperature to 30°C. The low-temperature, low-pressure liquid R365mfc then flows through the seventh heat exchanger 40, absorbing heat released by the working fluid in the high-temperature heat pump cycle, raising its temperature to 45°C. The heated R365mfc is then pressurized by the working fluid pump 15 and enters the fifth heat exchanger 38, thus completing the organic Rankine cycle. The circulating working fluid water absorbs heat released by the working fluid of the organic Rankine cycle through the sixth heat exchanger 39. The water enters the sixth heat exchanger 39 at a temperature of 18°C ​​and exits at 25°C. The heated water then enters the first cooling tower 16 for cooling. The cooling water is then pumped back into the sixth heat exchanger 39 by the third water pump 17, completing the cooling water circulation. The mine water waste heat utilization subsystem is activated, in which the high-temperature heat pump cycle also uses R365mfc as the working fluid. It releases heat to the organic Rankine cycle through the seventh heat exchanger 40. The R365mfc enters the seventh heat exchanger 40 at a temperature of 70°C and exits at 50°C. After cooling, it enters the second throttling valve 28 for throttling. After throttling, it enters the eighth heat exchanger 41 to absorb heat released by the working fluid of the mine water circulation. The R365mfc enters the eighth heat exchanger 41 at a temperature of 18°C ​​and exits at 20°C. After being heated, the gas enters the second compressor 29 for further heating and pressurization. The high-temperature and high-pressure gas then enters the seventh heat exchanger 40, completing the high-temperature heat pump cycle. The mine water in the mine water circulation is maintained at 22°C. The water is sent to the eighth heat exchanger 41 by the fourth water pump 32 to release heat to the high-temperature heat pump cycle. The cooled water returns to the mine water pool 30 and is heated again, thus completing the mine water circulation.

[0029] Step 4, the grid load becomes G0′, and the system load is G′.

[0030] Step 5, based on step 2, if the system load G′ is still greater than the grid load G0′, and the Carnot battery is fully charged when the capacity V of the high-temperature water tank 10 reaches its maximum value, then the gas waste heat utilization subsystem is adjusted to enter a low-load operation state, reducing the gas power generation output by decreasing the methane supply to the methane storage tank 18. The high-temperature flue gas volume is thus reduced, and the high-temperature flue gas flows sequentially through the first heat exchanger 34 and the second heat exchanger 35 before entering the waste heat boiler 21. Consequently, the output of the waste heat boiler 21 decreases, the amount of steam entering the second turbine 22 decreases, and the output of the fourth generator 23 decreases. Based on step 2, if the system load G′ is less than the grid load G0′ at this time, the system executes step 3; Step 6: Based on step 3, if the system load G′ is still less than the grid load G0′ at this time, the system executes step 3 again; Based on step 3, if the system load G′ is greater than the grid load G0′ at this time, the system executes step 2; Step 7, the grid load becomes G0′′, and the system load is G′′ at this time; Step 8: If the system load G′′ is still greater than the grid load G0′′, the sCO2-EGS subsystem is adjusted to enter a low-load operation state. The mass flow rate of sCO2 entering the carbon dioxide injection well is reduced by adjusting the speed of the first gas compressor 5, thereby reducing the output of the first generator 4. At this time, the total power output of the system reaches the minimum value. If the system load G′ is less than the grid load G0′ at this time, the system will proceed to step 3.

Claims

1. A Carnot battery and carbon dioxide-enhanced geothermal system for mining areas, characterized in that, It includes an sCO2-EGS subsystem, which is connected to a Carnot battery subsystem via a pipeline. The Carnot battery subsystem is connected to a mine water waste heat utilization subsystem via a pipeline. The sCO2-EGS subsystem is also connected to a gas waste heat utilization subsystem via a pipeline. It also includes a power bus (33). The sCO2-EGS subsystem, the Carnot battery subsystem, the mine water waste heat utilization subsystem, and the gas waste heat utilization subsystem are all connected to the power bus (33) via conductors.

2. The Carnot battery and carbon dioxide enhanced geothermal system for mining areas according to claim 1, characterized in that, The sCO2-EGS subsystem includes a carbon dioxide production well (1), which is connected to a first heat exchanger (34) via a pipeline. The outlet of the first heat exchanger (34) is connected in sequence to a high-pressure turbine (2), a low-pressure turbine (3), and a first generator (4) via a shaft. The first generator (4) is connected to the power bus (33) via a wire. The subsystem also includes a second heat exchanger (35), whose inlet is connected to the exhaust port of the high-pressure turbine (2), and whose outlet is connected to the inlet of the low-pressure turbine (3). The exhaust port of the low-pressure turbine (3) is connected to the Carnot battery subsystem. The Carnot battery subsystem is connected to a first gas compressor (5) via a pipeline. The first gas compressor (5) is connected to a carbon dioxide injection well (6) via a pipeline.

3. The Carnot battery and carbon dioxide enhanced geothermal system for mining areas according to claim 2, characterized in that, The Carnot battery subsystem includes a heat pump circulation system, which includes a third heat exchanger (36). The inlet end of the condenser side of the third heat exchanger (36) is connected to the exhaust port of the low-pressure turbine (3) through a pipe. The outlet end of the condenser side of the third heat exchanger (36) is connected to the first gas compressor (5) through a pipe. The evaporator side of the third heat exchanger (36) is connected in sequence to the first compressor (7), the heat storage circulation system, and the first throttle valve (8) through a pipe. The outlet of the first throttle valve (8) is connected to the third heat exchanger (36) through a pipe to form a circulation loop. The first compressor (7) is connected to the power bus (33) through a wire.

4. The Carnot battery and carbon dioxide enhanced geothermal system for mining areas according to claim 3, characterized in that, The heat storage circulation system includes a fourth heat exchanger (37). The inlet end of the condensing side of the fourth heat exchanger (37) is connected to the first compressor (7) through a pipe. The outlet end of the condensing side of the fourth heat exchanger (37) is connected to the first throttle valve (8) through a pipe. The evaporating side of the fourth heat exchanger (37) is connected in sequence to a first water pump (9), a high-temperature water tank (10), an organic Rankine circulation system, a low-temperature water tank (11), and a second water pump (12) through pipes. The outlet end of the second water pump (12) is connected to the fourth heat exchanger (37) through a pipe to form a circulation loop.

5. The Carnot battery and carbon dioxide enhanced geothermal system for mining areas according to claim 4, characterized in that, The organic Rankine cycle system includes a fifth heat exchanger (38). The inlet end of the condenser side of the fifth heat exchanger (38) is connected to the high-temperature water tank (10) through a pipe. The outlet end of the condenser side of the fifth heat exchanger (38) is connected to the low-temperature water tank (11) through a pipe. The evaporator side of the fifth heat exchanger (38) is connected in sequence to a first turbine (13), a cooling water circulation system, a mine water waste heat utilization subsystem, and a working fluid pump (15) through pipes. The working fluid pump (15) is connected to the fifth heat exchanger (38) through a pipe to form a circulation loop. The first turbine (13) is connected to a second generator (14) through a shaft. The second generator (14) is connected to the power bus (33) through a wire.

6. The Carnot battery and carbon dioxide-enhanced geothermal system for mining areas according to claim 5, characterized in that, The cooling water circulation system includes a sixth heat exchanger (39). The inlet end of the condensing side of the sixth heat exchanger (39) is connected to the first turbine (13) through a pipe. The outlet end of the condensing side of the sixth heat exchanger (39) is connected to the mine water waste heat utilization subsystem through a pipe. The evaporating side of the sixth heat exchanger (39) is connected to the first cooling tower (16) and the third water pump (17) in sequence through a pipe. The third water pump (17) is connected to the sixth heat exchanger (39) through a pipe to form a circulation loop.

7. The Carnot battery and carbon dioxide enhanced geothermal system for mining areas according to claim 6, characterized in that, The mine water waste heat utilization subsystem includes a seventh heat exchanger (40). The inlet end of the evaporation side of the seventh heat exchanger (40) is connected to the sixth heat exchanger (39) through a pipe. The outlet end of the evaporation side of the seventh heat exchanger (40) is connected to the working fluid pump (15) through a pipe. The condenser side of the seventh heat exchanger (40) is connected in sequence to a second throttle valve (28), an eighth heat exchanger (41), and a second compressor (29) through pipes. The second compressor (29) is connected to the seventh heat exchanger (40) through a pipe to form a circulation loop. The eighth heat exchanger (41) is connected to a mine water tank (30) through a pipe. The mine water tank (30) is connected to a fourth water pump (32) through a pipe. The fourth water pump (32) is connected to the eighth heat exchanger (41) through a pipe to form a circulation loop. A water surface photovoltaic (31) is installed in the mine water tank (30). The water surface photovoltaic (31) is connected to the power bus (33) through a wire.

8. The Carnot battery and carbon dioxide enhanced geothermal system for mining areas according to claim 7, characterized in that, The gas waste heat utilization subsystem includes a methane storage tank (18), which is connected to an internal combustion engine (19) via a pipeline. The internal combustion engine (19) is connected to a third generator (20) via a shaft. The third generator (20) is connected to the power bus (33) via a wire. The internal combustion engine (19) is connected to the first heat exchanger (34) and the second heat exchanger (35) in sequence via pipelines. The second heat exchanger (35) is connected to a waste heat boiler (21), a second turbine (22), and a... The second cooling tower (24) and the second turbine (22) are connected to the fourth generator (23) via a shaft. The fourth generator (23) is connected to the power bus (33) via a wire. One flue gas outlet of the waste heat boiler (21) is connected to the chimney (27) via a pipe. The other flue gas outlet of the waste heat boiler (21) is connected to the carbon dioxide purifier (25) and the second gas compressor (26) via a pipe. The outlet of the second gas compressor (26) is connected to the inlet of the first gas compressor (5).

9. An operation method for a Carnot battery and carbon dioxide-enhanced geothermal system for mining areas, characterized in that, The Carnot battery and carbon dioxide enhanced geothermal system for mining areas according to claim 8 includes the following steps: Step 1: Set the power grid load G0, system load G, and water tank capacity V; Step 2: If G > G0, the sCO2-EGS and gas waste heat subsystem operate normally, the Carnot battery enters the charging state, the heat pump circulates to absorb and store heat, and the other circulation and mine water subsystems are shut down. Step 3: If G < G0, the Carnot battery enters the discharge state, the heat storage cycle releases heat to drive the organic Rankine cycle to generate electricity, and the mine water subsystem is activated to recover waste heat. Step 4: When the power grid load changes, adjust the system output by regulating the gas supply or sCO2 injection flow rate to maintain load balance.

10. The operation method of the Carnot battery and carbon dioxide enhanced geothermal system for mining areas according to claim 9, characterized in that, Step 2 is specifically as follows: If the system load G is greater than the grid load G0, the sCO2-EGS subsystem and the gas waste heat utilization subsystem operate normally first; the Carnot battery subsystem enters the charging state, at which time the heat pump cycle system is turned on. The working fluid of the heat pump cycle system absorbs heat on the evaporation side through the third heat exchanger to become superheated steam, and then enters the first compressor to be heated and pressurized. The electrical energy required by the first compressor is provided by the first generator. The high temperature and high pressure gas transfers heat to the heat storage cycle system on the condensation side through the fourth heat exchanger, and then throttles in the first throttling valve to complete the heat pump cycle. The fifth heat exchanger of the thermal storage circulation system is shut down, while the others are turned on. The working fluid water of the thermal storage circulation system is pressurized by the second water pump from the low-temperature water tank and enters the fourth heat exchanger. The fourth heat exchanger absorbs heat from the working fluid of the heat pump circulation. The heated water is then sent to the high-temperature water tank by the first water pump for storage, thus completing the thermal storage system cycle. The organic Rankine cycle and cooling water cycle are both shut down, and the mine water waste heat utilization subsystem is shut down. Step 3 specifically involves the following steps: If the system load G is less than the grid load G0, the sCO2-EGS subsystem and the waste gas heat utilization subsystem operate normally, and the Carnot battery subsystem enters a discharge state. At this time, the heat pump cycle is shut down, the fourth heat exchanger of the heat storage cycle is shut down, and the other parts are turned on. The working fluid water of the heat storage cycle enters the fifth heat exchanger from the high-temperature water tank, and releases heat to the working fluid of the organic Rankine cycle through the fifth heat exchanger. The cooled water enters the low-temperature water tank for storage, thus completing the heat storage cycle. Both the organic Rankine cycle and the cooling water cycle are turned on. The working fluid of the organic Rankine cycle absorbs the heat released by the working fluid water of the heat storage cycle through the fifth heat exchanger on the evaporation side. The heated working fluid enters the first turbine, which drives the second generator to generate electricity. The working fluid after doing work flows through the sixth heat exchanger to release heat to the working fluid water of the cooling water cycle. The low-temperature, low-pressure working fluid then flows through the seventh heat exchanger to absorb the heat released by the working fluid of the high-temperature heat pump cycle. The working fluid, pressurized by the working fluid pump, enters the fifth heat exchanger, thus completing the organic Rankine cycle. The working fluid in the cooling water circulation absorbs the heat released by the working fluid in the organic Rankine cycle through the sixth heat exchanger. The heated water enters the first cooling tower for cooling, and the cooled water is sent to the sixth heat exchanger by the third water pump, completing the cooling water circulation. The mine water waste heat utilization subsystem is activated, and the working fluid in the high-temperature heat pump cycle releases heat to the working fluid in the organic Rankine cycle through the seventh heat exchanger. The cooled working fluid enters the second throttling valve for throttling, and the throttled working fluid enters the eighth heat exchanger to absorb the heat released by the working fluid in the mine water circulation. The heated working fluid enters the second compressor for further heating and pressurization. The high-temperature, high-pressure gas enters the sixth heat exchanger, completing the high-temperature heat pump cycle. The working fluid in the mine water circulation is sent to the seventh heat exchanger by the fourth water pump to release heat to the working fluid in the high-temperature heat pump cycle. The cooled working fluid returns to the mine water pool for reheating, thus completing the mine water circulation. Step 4 specifically involves: The grid load becomes G0′, and the system load is G′. Based on step 2, if the system load G′ is still greater than the grid load G0′, and the Carnot battery is fully charged when the high-temperature water tank capacity V reaches its maximum value, the load of the gas waste heat utilization subsystem is reduced first, and the gas power generation output is reduced by reducing the amount of methane supplied. The amount of high-temperature flue gas is thus reduced, and the high-temperature flue gas flows through the first heat exchanger and the second heat exchanger in sequence, and enters the waste heat boiler, thereby reducing the output of the waste heat boiler and the amount of steam entering the second turbine, thereby reducing the output of the fourth generator. Based on step 2, if the system load G′ is less than the grid load G0′, the system executes step 3. If the system load G′ is still less than the grid load G0′, the system executes step 3 again. Based on step 3, if the system load G′ is greater than the grid load G0′, the system executes step 2. When the grid load becomes G0′′, the system load is G′′. If the system load G′′ is still greater than the grid load G0′′, the sCO2-EGS subsystem enters a low-load operation state. By adjusting the speed of the first gas compressor, the mass flow rate of sCO2 injected into the formation is reduced, thereby reducing the output of the first generator. At this time, the total power generation output of the system reaches the minimum value. If the system load G′ is less than the grid load G0′ at this time, the system will proceed to step 3.

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