Adjustable hot dry rock thermal power coupling cascade utilization system based on compressed air energy storage

Abstract

The present invention discloses an adjustable hot dry rock thermoelectric coupling cascade utilization system based on compressed air energy storage, including: a hot dry rock mining system, a geothermal power generation system, a power grid, a compressed air energy storage system, a thermal energy comprehensive utilization system and a tail water treatment system; the hot dry rock mining system is used to extract heat from the hot dry rock reservoir and is connected to the geothermal power generation system; the geothermal power generation system is used to convert the extracted heat energy into electrical energy and is connected to the power grid, the compressed air energy storage system and the thermal energy comprehensive utilization system; the compressed air energy storage system is used to store the remaining electrical energy in the form of high-pressure air and is connected to the power grid; the thermal energy comprehensive utilization system is used to comprehensively utilize the residual heat of the cryogenic fluid and is connected to the tail water treatment system; the tail water treatment system is used to purify the tail water and is connected to the hot dry rock mining system. The technical solution of the present invention can significantly improve the utilization rate and production efficiency of hot dry rock geothermal resources and contribute to the stability of power supply to the power grid.

Description

Technical Field

[0001] The present invention belongs to the technical field of hot dry rock geothermal utilization, and in particular relates to an adjustable hot dry rock thermoelectric coupling cascade utilization system based on compressed air energy storage. Background Art

[0002] Hot dry rock geothermal resources are considered as a powerful alternative to fossil energy due to their large reserves, wide distribution, renewable nature, low pollution, high safety and good stability. my country has extremely rich reserves of hot dry rocks, with reserves of 2.09×10 25 J, equivalent to 7.149×10 12 Tons of standard coal. The mining principle is to inject low-temperature fluids through at least two wells deep into the reservoir and recover high-temperature fluids to achieve the heat extraction process, and then convert the thermal energy of the high-temperature fluids into electrical energy through power generation equipment, thereby realizing the utilization of dry hot rock geothermal resources. However, the temperature of geothermal tail water after the power generation equipment usually maintains a high temperature of 80-90°C. If it is directly injected into the reservoir again, a large amount of heat energy will be wasted; and the large amount of mineral components contained in the tail water will cause precipitation due to the decrease in temperature and pressure at the injection end, causing scaling of the well wall or clogging of cracks, greatly reducing system stability and production efficiency; in addition, due to the peak and trough periods of residential electricity consumption, there may be insufficient power supply during peak periods and a large amount of power wasted during trough periods, which will affect the stability of the power grid. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide an adjustable hot dry rock thermoelectric coupling cascade utilization system based on compressed air energy storage, which can significantly improve the utilization rate and production efficiency of hot dry rock geothermal resources and help stabilize the power supply of the power grid; the present invention realizes the hot dry rock thermoelectric coupling cascade utilization by generating electricity through high-temperature fluid and directly utilizing the thermal energy in the low-temperature fluid after power generation, and also utilizes compressed air energy storage technology to regulate the power supply, and reduces scaling and other problems through the tail water treatment system, which will improve the production efficiency and utilization rate of hot dry rock geothermal resources while maintaining the stability of the system.

[0004] To achieve the above object, the present invention adopts the following technical solution:

[0005] A controllable hot dry rock thermoelectric coupling cascade utilization system based on compressed air energy storage, comprising: a hot dry rock mining system, a geothermal power generation system, a power grid, a compressed air energy storage system, a heat energy comprehensive utilization system and a tail water treatment system; wherein the hot dry rock mining system is used to extract heat from the hot dry rock reservoir and is connected to the geothermal power generation system; the geothermal power generation system is used to convert the extracted heat energy into electrical energy and is connected to the power grid, the compressed air energy storage system and the heat energy comprehensive utilization system; the compressed air energy storage system is used to store the remaining electrical energy in the form of high-pressure air and is connected to the power grid; the heat energy comprehensive utilization system is used to comprehensively utilize the residual heat of the low-temperature fluid and is connected to the tail water treatment system; the tail water treatment system is used to purify the tail water and is connected to the hot dry rock mining system; the fluid is injected through the injection well, heated by the hot dry rock reservoir and converted into a high-temperature fluid and recovered through the production well, the high-temperature fluid is converted into a low-temperature fluid after flowing through the geothermal power generation system, the low-temperature fluid is converted into tail water after passing through the geothermal comprehensive utilization system, the tail water is converted into a working fluid after passing through the tail water treatment system, and the working fluid is injected into the hot dry rock mining system through the injection well.

[0006] Preferably, the hot dry rock mining system includes: a mining well, an injection well, a mining water pump and an injection water pump; the mining well and the injection well should reserve a pump chamber section of not less than 500m; the left end of the injection water pump is connected to the tailwater treatment system through a pipeline, which is used to inject the working fluid into the hot dry rock reservoir through the injection well; the left end of the mining water pump is connected to the production well, which is used to extract the working fluid heated by the hot dry rock reservoir from the reservoir; the right end is connected to the geothermal power generation system through a pipeline, which is used to pump the high-temperature fluid to the geothermal power generation system.

[0007] The geothermal power generation system adopts a two-stage flash evaporation system, including: a high-pressure throttle valve, a low-pressure throttle valve, a high-pressure steam-water separator, a low-pressure steam-water separator, a dehumidifier, a steam valve, a high-pressure steam turbine, a low-pressure steam turbine, a generator and a transformer; wherein the high-pressure steam-water separator is used to separate a high-pressure steam-liquid mixture, and is provided with an inlet and two outlets, a high-pressure throttle valve is provided at the left inlet to maintain a stable flow rate entering the high-pressure steam-water separator, the right liquid outlet is connected to the low-pressure steam-water separator through a pipeline, and the upper steam outlet is connected to the dehumidifier through a pipeline; the low-pressure steam-water separator is used to separate a low-pressure steam-liquid mixture, a low-pressure throttle valve is provided on the left to maintain a stable flow rate entering the low-pressure steam-water separator, the right liquid outlet is connected to the thermal energy comprehensive utilization system through a pipeline, and the upper side is connected to the low-pressure steam turbine through a pipeline; the dehumidifier is used to remove excess moisture in the high-pressure steam, and the upper side thereof is connected to the high-pressure steam through a pipeline The high-pressure steam is transported to the high-pressure steam turbine, and the left side is connected to the comprehensive utilization system of thermal energy through a pipeline, and a steam valve is provided to allow only liquid water to pass through; both the high-pressure steam turbine and the low-pressure steam turbine are provided with an air inlet and an air outlet, and the air outlet of the high-pressure steam turbine is connected to the air inlet of the low-pressure steam turbine through a pipeline, and the high-pressure steam flowing through the high-pressure steam turbine will be further used as steam supplement for the low-pressure steam turbine after being converted into low-pressure steam, and the outlet of the low-pressure steam turbine is connected to the comprehensive utilization system of thermal energy; the high-pressure steam turbine and the low-pressure steam turbine are used to convert the thermal energy of steam into mechanical energy, and are connected by a transmission shaft, and the right side of the low-pressure steam turbine is connected to the generator, and the high-pressure steam turbine and the low-pressure steam turbine drive the generator to rotate to realize the power generation process; the right side of the generator is connected to the transformer to ensure the high voltage required by the power grid; the right end of the transformer is connected to the power grid and the compressed air energy storage system, and the surplus electric energy during low-peak electricity consumption will be handed over to the compressed air energy storage system for storage in the form of high-pressure gas.

[0008] Preferably, the compressed air energy storage system comprises an electric motor, a primary compressor, a secondary compressor, a tertiary compressor, an air storage tank, a primary expander, a secondary expander, a tertiary expander, a generator, and a transformer; the left side of the electric motor is connected to the geothermal power generation system, and is used to convert the remaining electrical energy into mechanical energy and drive the multi-stage compressor on the right side to work; the multi-stage compressor and the multi-stage expander are both provided with an air inlet and an air outlet, the air inlet of the primary compressor is connected to the air, the air outlet of the three-stage compressor is connected to the air storage tank, the air inlet of the primary compressor, the air inlet and air outlet of the secondary compressor, and the air inlet of the three-stage compressor are connected in sequence, and the remaining electrical energy is stored in the air storage tank in the form of high-pressure gas through the compression process of the multi-stage compressor; the air inlet on the left side of the primary expander is connected to the air storage tank, and the air outlet of the three-stage expander is connected to the atmosphere, the air outlet of the primary expander, the air inlet and air outlet of the second-stage expander, and the air inlet of the three-stage expander are connected in sequence, and the multi-stage compressor drives the generator to work during the release of high-pressure gas, converts energy into electrical energy, and transmits it to the power grid after voltage conversion by the transformer.

[0009] Preferably, the comprehensive utilization system of heat energy includes a three-way valve, a primary plate heat exchanger, a secondary plate heat exchanger, a tertiary plate heat exchanger, a primary heat collection module, a secondary heat collection module, a tertiary heat collection module and three user-end water pumps; both ends of the primary plate heat exchanger are connected to the main pipeline, the heat exchange end is connected to the primary heat collection module and the user-end water pump, the primary heat collection module is used for household heating or bathing, and the user-end water pump is used to maintain water circulation; both ends of the secondary plate heat exchanger are connected to the main pipeline, the heat exchange end is connected to the secondary heat collection module and the user-end water pump, and the secondary heat collection module is used for industrial production; both ends of the tertiary plate heat exchanger are connected to the main pipeline, connected to the tertiary heat collection module and the user-end water pump, and the tertiary heat collection module is used for agricultural and aquaculture production; the left side of the main pipeline is connected to the tail water treatment system.

[0010] Preferably, the tailwater treatment system includes: a water purification device and a water storage device; the upper side of the water purification device is connected to the main pipeline for treating a large amount of mineral ions in the tailwater; the upper side of the water storage device is connected to the water purification device for receiving and storing the working fluid, and the working fluid is re-injected into the hot dry rock reservoir by the injection pump on the right side to realize the extraction cycle.

[0011] Preferably, the temperature of the low-temperature fluid itself is higher than that of the working fluid. After the high-temperature fluid flows through the geothermal power generation system, part of its heat energy is utilized for power generation. Subsequently, the low-temperature fluid with a temperature lower than that of the high-temperature fluid flows through the comprehensive thermal energy utilization system for secondary heat recovery.

[0012] Preferably, the pump chamber section at the upper end of the production well and the injection well should be reinforced with high temperature resistant and corrosion resistant cement material.

[0013] Firstly, the geothermal power generation system of the present invention can generate electricity from geothermal energy and increase the stability of the power grid through compressed air energy storage technology; secondly, the low-temperature fluid after power generation is collected through the comprehensive thermal energy utilization system to realize the geothermal thermal-electric coupling cascade utilization, and complete the effective exploitation and rational utilization of geothermal energy; finally, the tail water treatment system can purify the tail water, reduce the scaling problem of the geothermal exploitation system, improve the system exploitation efficiency, and realize the perfect closed loop of clean new energy.

[0014] The beneficial effects of the present invention are as follows:

[0015] (1) A two-stage flash geothermal power generation system is used, with a minimum power generation temperature of 90°C. At the same time, high-temperature geothermal power generation above 140°C can be achieved, with high geothermal utilization and high system efficiency.

[0016] (2) Combine geothermal power generation technology with compressed air energy storage technology. During the low-power consumption period, the remaining electricity will be stored in the compressed air energy storage system. During the peak power consumption period, the compressed air energy storage system will supplement the power supply to the power grid, thereby reducing power waste while enhancing the stability of the power supply of the power grid and achieving a regulatory effect.

[0017] (3) Through the comprehensive thermal energy utilization system, the thermal energy of the low-temperature fluid after power generation is reused for heating, bathing, industrial production, agriculture, and aquaculture industries, thereby improving the utilization rate of geothermal energy and realizing the thermoelectric coupled cascade utilization of dry shale geothermal resources.

[0018] (4) The tailwater treatment system is used to purify the geothermal tailwater after use, reduce its mineral content, and solve the problems of wellbore scaling and fissure blockage at the source, thereby minimizing the significant decrease in reservoir permeability and helping to ensure the production efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0020] Figure 1 This is a schematic structural diagram of an adjustable hot dry rock thermoelectric coupling cascade utilization system based on compressed air energy storage according to an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the working principle of an adjustable hot dry rock thermoelectric coupling cascade utilization system based on compressed air energy storage according to an embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of the structure of a hot dry rock mining system according to an embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the structure of a geothermal power generation system according to an embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram of the structure of a compressed air energy storage system according to an embodiment of the present invention;

[0025] Figure 6 This is a schematic diagram of the structure of a thermal energy comprehensive utilization system according to an embodiment of the present invention;

[0026] Figure 7 This is a schematic diagram of the structure of a tailwater treatment system according to an embodiment of the present invention;

[0027] Among them, 1- mining well; 2- mining water pump; 3- high-pressure throttle valve; 4- high-pressure steam-water separator; 5- low-pressure throttle valve; 6- low-pressure steam-water separator; 7- dehumidifier; 8- steam valve; 9- high-pressure steam turbine; 10- low-pressure steam turbine; 11- generator; 12- transformer; 13- power grid; 14- motor; 15- first-stage compressor; 16- second-stage compressor; 17- third-stage compressor; 18- gas storage tank; 19- -stage expander; 20-second stage expander; 21-third stage expander; 22-generator; 23-transformer; 24-three-way valve; 25-first stage plate heat exchanger; 26-user-end water pump; 27-first stage heat collection module; 28-second stage plate heat exchanger; 29-second stage heat collection module; 30-third stage plate heat exchanger; 31-third stage heat collection module; 32-water purification equipment; 33-water storage equipment; 34-injection water pump; 35-injection well. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] Embodiment 1:

[0031] like Figure 1-7 As shown, an embodiment of the present invention provides an adjustable hot dry rock thermoelectric coupling cascade utilization system based on compressed air energy storage, including: a hot dry rock mining system, a geothermal power generation system, a power grid, a compressed air energy storage system, a thermal energy comprehensive utilization system and a tailwater treatment system. The hot dry rock mining system is used to extract heat from the hot dry rock reservoir and is connected to the geothermal power generation system. The geothermal power generation system is used to convert the extracted thermal energy into electrical energy and is connected to the power grid, the compressed air energy storage system and the thermal energy comprehensive utilization system. The compressed air energy storage system is used to store the remaining electrical energy in the form of high-pressure air and is connected to the power grid at the bottom. The thermal energy comprehensive utilization system is used to comprehensively utilize the residual heat of the low-temperature fluid and is connected to the tailwater treatment system. The tailwater treatment system is used to purify the working fluid and is connected to the hot dry rock mining system.

[0032] As an implementation method of an embodiment of the present invention, a hot dry rock mining system includes a mining well (1), an injection well (35), a mining water pump (2) and an injection water pump (34); the mining well (1) and the injection well (35) should reserve a pump chamber section of not less than 500 m, and at the same time, use high temperature and corrosion resistant cement materials for reinforcement to prevent the upper loose strata from collapsing; the left end of the injection water pump (34) is connected to the tailwater treatment system through a pipeline, and is used to inject the working fluid into the hot dry rock reservoir after hydraulic fracturing and permeability enhancement through the injection well (35); the left end of the mining water pump (2) is connected to the production well (1), and is used to extract the high-temperature fluid heated by the hot dry rock reservoir from the reservoir; the right end is connected to the geothermal power generation system through a pipeline, and is used to pump the high-temperature fluid to the geothermal power generation system. The pump chamber section at the upper end of the mining well and the injection well should be reinforced with high temperature and corrosion resistant cement materials to prevent the upper loose strata from collapsing. The production water pump and injection water pump should have the ability to prevent water hammer effect to avoid excessive pressure on the production well and injection well at the moment of valve opening and closing, causing damage.

[0033] As an implementation method of an embodiment of the present invention, a geothermal power generation system adopts a two-stage flash evaporation system, including a high-pressure throttle valve (3), a low-pressure throttle valve (5), a high-pressure steam-water separator (4), a low-pressure steam-water separator (6), a dehumidifier (7), a steam valve (8), a high-pressure steam turbine (9), a low-pressure steam turbine (10), a generator (11) and a transformer (12); the high-pressure steam-water separator (4) is used to separate a high-pressure steam-liquid mixture, and is provided with an inlet and two outlets. A high-pressure throttle valve (3) is provided at the left inlet to keep the high-pressure steam-water separator from entering the high-pressure steam-water separator. The flow rate of the separator (4) is stable. The right liquid outlet is connected to the low-pressure steam-water separator (6) through a pipeline, and the upper steam outlet is connected to the dehumidifier (7) through a pipeline. The low-pressure steam-water separator (6) is used to separate the low-pressure steam-liquid mixture. A low-pressure throttle valve (5) is provided on the left side to maintain the flow rate entering the low-pressure steam-water separator (6) stable. The right liquid outlet is connected to the thermal energy comprehensive utilization system through a pipeline, and the upper side is connected to the low-pressure steam turbine (10) through a pipeline. The dehumidifier (7) is used to remove excess moisture in the high-pressure steam. The upper side is connected to the low-pressure steam turbine (10) through a pipeline. The high-pressure steam is transported to the high-pressure steam turbine (9), the left side of which is connected to the comprehensive utilization system of thermal energy through a pipeline, and a steam valve (8) is provided to allow only liquid water to pass through; the high-pressure steam turbine (9) and the low-pressure steam turbine (10) are both provided with an air inlet and an air outlet, the air outlet of the high-pressure steam turbine (9) is connected to the air inlet of the low-pressure steam turbine (10) through a pipeline, the high-pressure steam flowing through the high-pressure steam turbine (9) is converted into low-pressure steam and will be further used as steam supplement for the low-pressure steam turbine (10), and the outlet of the low-pressure steam turbine (10) is connected to the comprehensive utilization system of thermal energy; the high-pressure steam The turbine (9) and the low-pressure steam turbine (10) are used to convert the thermal energy of steam into mechanical energy. They are connected to each other via a transmission shaft. The right side of the low-pressure steam turbine (10) is connected to the generator (11). The high-pressure steam turbine (9) and the low-pressure steam turbine (10) drive the generator to rotate to realize the power generation process. The right side of the generator (11) is connected to the transformer (12) to ensure the high voltage required by the power grid. The right end of the transformer (12) is connected to the power grid (13) and the compressed air energy storage system. The surplus electric energy during the low-peak period will be handed over to the compressed air energy storage system for storage in the form of high-pressure gas.

[0034] As an implementation mode of an embodiment of the present invention, a compressed air energy storage system comprises an electric motor (14), a first-stage compressor (15), a second-stage compressor (16), a third-stage compressor (17), an air storage tank (18), a first-stage expander (19), a second-stage expander (20), a third-stage expander (21), a generator (22), and a transformer (23); the left side of the electric motor (14) is connected to a geothermal power generation system for converting surplus electrical energy into mechanical energy and driving the multi-stage compressor on the right side to work; the multi-stage compressor and the multi-stage expander are both provided with an air inlet and an air outlet, the air inlet of the first-stage compressor (15) is connected to air, the air outlet of the third-stage compressor (17) is connected to the air storage tank (18), and the first-stage compressor (15) is connected to the air. The air inlet of the compressor (15), the air inlet and the air outlet of the second-stage compressor (16), and the air inlet of the third-stage compressor (17) are connected in sequence, and the surplus electric energy is stored in the form of high-pressure gas in the gas storage tank (18) through the compression process of the multi-stage compressor; the left air inlet of the first-stage expander (19) is connected to the gas storage tank (18), and the air outlet of the third-stage expander (21) is connected to the atmosphere; the air outlet of the first-stage expander (19), the air inlet and the air outlet of the second-stage expander (20), and the air inlet of the third-stage expander (21) are connected in sequence, and the multi-stage compressor drives the generator (22) to work during the process of releasing the high-pressure gas, converts the energy into electric energy, and transmits it to the power grid (13) after the voltage is converted by the transformer (23).

[0035] As an implementation method of an embodiment of the present invention, a heat energy comprehensive utilization system includes a three-way valve (24), a primary plate heat exchanger (25), a secondary plate heat exchanger (28), a tertiary plate heat exchanger (30), a primary heat collection module (27), a secondary heat collection module (29), a tertiary heat collection module (31) and three user-end water pumps (26); both ends of the primary plate heat exchanger (25) are connected to the main pipeline, the heat exchange end is connected to the primary heat collection module (27) and the user-end water pump (26), and the primary heat collection module (27) ) is used for household heating or bathing, and the user-end water pump (26) is used to maintain water circulation; both ends of the secondary plate heat exchanger (28) are connected to the main pipeline, and the heat exchange end is connected to the secondary heat collection module (29) and the user-end water pump (26), and the secondary heat collection module (29) is used for industrial production; both ends of the tertiary plate heat exchanger (28) are connected to the main pipeline, and are connected to the tertiary heat collection module (31) and the user-end water pump (26), and the tertiary heat collection module (31) is used for agricultural and aquaculture production; the left side of the main pipeline is connected to the tail water treatment system.

[0036] As an implementation method of an embodiment of the present invention, the tailwater treatment system includes a water purification device (32) and a water storage device (33); the upper side of the water purification device (32) is connected to the main pipeline for treating a large amount of mineral ions in the tailwater; the upper side of the water storage device (33) is connected to the water purification device (32) for receiving and storing the working fluid, and then re-injecting the working fluid into the hot dry rock reservoir through the right-side injection pump (34) to realize the extraction cycle.

[0037] As an implementation method of the present invention, in the hot dry rock mining system, geothermal power generation system, compressed air energy storage system, thermal energy comprehensive utilization system and tailwater treatment system, all channels through which fluids flow are made of high temperature resistant, high pressure resistant and corrosion resistant materials, and are provided with insulation layers.

[0038] The working principle of the adjustable hot dry rock thermoelectric coupling cascade utilization system based on compressed air energy storage in the embodiment of the present invention is as follows:

[0039] When the production water pump (2) extracts the heated high-temperature fluid from the hot dry rock reservoir through the production well (1), it is first transported to the high-pressure steam-water separator (4) in the geothermal power generation system. The pressure drop between the production well (1) and the high-pressure steam-water separator (4) causes the high-temperature fluid to become a high-pressure steam-liquid mixture and is separated by the high-pressure steam-water separator (4). The high-pressure steam will be transported to the dehumidifier (7), and the liquid will be transported to the low-pressure steam-water separator (6). The pressure drop between the high-pressure steam-water separator (4) and the low-pressure steam-water separator (6) causes the high-temperature fluid to become a low-pressure steam-liquid mixture and is separated by the low-pressure steam-water separator (6). The low-pressure steam will be transported to the low-pressure steam turbine (10), and the liquid will be transported to the comprehensive thermal energy utilization system. The dehumidifier (7) will further remove excess water in the high-pressure steam, transport the high-pressure steam to the high-pressure steam turbine (9), and transport the liquid to the comprehensive thermal energy utilization system. The high-pressure steam will drive the high-pressure steam turbine (9) to rotate, and then the high-pressure steam will become low-pressure steam and be transported to the low-pressure steam turbine (10) to drive the low-pressure steam turbine (10) to rotate together with the low-pressure steam separated by the low-pressure steam-water separator (6). At the same time, the low-pressure steam will become a medium-low temperature liquid of 80-90°C and be transported to the comprehensive thermal energy utilization system. The rotation of the two steam turbines will drive the generator (11) to rotate, thereby realizing the process of converting thermal energy into mechanical energy and then into electrical energy. During the peak period of electricity consumption, the electrical energy will be directly input into the power grid (13) to supply electricity to residents, and at night and other low-power periods, the remaining electrical energy will be handed over to the compressed air energy storage system to store in the form of high-pressure air, and during the peak period of electricity consumption, the high-pressure air will be released to generate electricity to supplement the power supply to the power grid (13), thereby realizing the regulation process. Afterwards, the comprehensive thermal energy utilization system will utilize the remaining thermal energy of the low-temperature fluid. In winter, the three-way valves at both ends of the primary plate heat exchanger (25) will be opened, and the circulating water in the primary heat collection module (27) will be heated by geothermal water at the primary plate heat exchanger (25) and mainly used for heating or bathing of residents, while in non-winter, the three-way valve will be closed and the primary plate heat exchanger (25) will stop working. Similarly, the circulating water in the secondary heat collection module (29) will be heated by geothermal water at the secondary plate heat exchanger (28) and mainly used for industrial production, such as drying, printing and dyeing, and papermaking; the circulating water in the tertiary heat collection module (31) will be heated by geothermal water at the tertiary plate heat exchanger (30) and mainly used for agricultural irrigation or aquaculture. In winter, the heat energy in the medium and low temperature geothermal energy after power generation will be mainly used in the primary heat collection module (25), while in non-winter it will be mainly used in the secondary heat collection module (29) and the tertiary heat collection module (31). By utilizing geothermal water through geothermal power generation system and comprehensive thermal energy utilization system, the thermal-electric coupled cascade utilization process of hot dry rock geothermal resources in this patent is realized.The low-temperature geothermal tail water after being utilized by the comprehensive thermal energy utilization system will be delivered to the tail water treatment system for purification. After a large amount of mineral components are removed, it will be re-injected into the hot dry rock reservoir through the injection well (35) by the injection pump (34). After being heated by the reservoir, it will become high-temperature geothermal water and will be mined and utilized again at the mining well (1), thereby realizing the recycling of the working fluid.

[0040] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A controllable hot dry rock thermoelectric coupling cascade utilization system based on compressed air energy storage, characterized in that: include: A hot dry rock mining system, a geothermal power generation system, a power grid, a compressed air energy storage system, a thermal energy comprehensive utilization system and a tail water treatment system; wherein the hot dry rock mining system is used to extract heat from the hot dry rock reservoir and is connected to the geothermal power generation system; the geothermal power generation system is used to convert the extracted thermal energy into electrical energy and is connected to the power grid, the compressed air energy storage system and the thermal energy comprehensive utilization system; the compressed air energy storage system is used to store the remaining electrical energy in the form of high-pressure air and is connected to the power grid; the thermal energy comprehensive utilization system is used to comprehensively utilize the residual heat of the low-temperature fluid and is connected to the tail water treatment system; the tail water treatment system is used to purify the tail water and is connected to the hot dry rock mining system; the fluid is injected through the injection well, heated by the hot dry rock reservoir and converted into a high-temperature fluid and recovered through the production well, the high-temperature fluid is converted into a low-temperature fluid after flowing through the geothermal power generation system, the low-temperature fluid is converted into tail water after passing through the geothermal comprehensive utilization system, the tail water is converted into a working fluid after passing through the tail water treatment system, and the working fluid is then injected into the hot dry rock mining system through the injection well; Wherein, the compressed air energy storage system comprises an electric motor, a primary compressor, a secondary compressor, a tertiary compressor, an air storage tank, a primary expander, a secondary expander, a tertiary expander, a generator, and a transformer; the left side of the electric motor is connected to the geothermal power generation system, which is used to convert the remaining electrical energy into mechanical energy and drive the multi-stage compressor on the right side to work; the multi-stage compressor and the multi-stage expander are both provided with an air inlet and an air outlet, the air inlet of the primary compressor is connected to the air, the air outlet of the three-stage compressor is connected to the air storage tank, the air inlet of the primary compressor, the air inlet and air outlet of the secondary compressor, and the air inlet of the three-stage compressor are connected in sequence, and the remaining electrical energy is stored in the air storage tank in the form of high-pressure gas through the compression process of the multi-stage compressor; the air inlet on the left side of the primary expander is connected to the air storage tank, and the air outlet of the three-stage expander is connected to the atmosphere, the air outlet of the primary expander, the air inlet and air outlet of the second-stage expander, and the air inlet of the three-stage expander are connected in sequence, and the multi-stage compressor drives the generator to work during the release of high-pressure gas, converts energy into electrical energy, and transmits it to the power grid after voltage conversion by the transformer; The geothermal power generation system adopts a two-stage flash evaporation system, including: a high-pressure throttle valve, a low-pressure throttle valve, a high-pressure steam-water separator, a low-pressure steam-water separator, a dehumidifier, a steam valve, a high-pressure steam turbine, a low-pressure steam turbine, a generator and a transformer; wherein the high-pressure steam-water separator is used to separate a high-pressure steam-liquid mixture, and is provided with an inlet and two outlets, a high-pressure throttle valve is provided at the left inlet to maintain a stable flow rate entering the high-pressure steam-water separator, the right liquid outlet is connected to the low-pressure steam-water separator through a pipeline, and the upper steam outlet is connected to the dehumidifier through a pipeline; the low-pressure steam-water separator is used to separate a low-pressure steam-liquid mixture, a low-pressure throttle valve is provided on the left to maintain a stable flow rate entering the low-pressure steam-water separator, the right liquid outlet is connected to the thermal energy comprehensive utilization system through a pipeline, and the upper side is connected to the low-pressure steam turbine through a pipeline; the dehumidifier is used to remove excess moisture in the high-pressure steam, and the upper side thereof is connected to the high-pressure steam through a pipeline The high-pressure steam is transported to the high-pressure steam turbine, and the left side is connected to the comprehensive utilization system of thermal energy through a pipeline, and a steam valve is provided to allow only liquid water to pass through; both the high-pressure steam turbine and the low-pressure steam turbine are provided with an air inlet and an air outlet, and the air outlet of the high-pressure steam turbine is connected to the air inlet of the low-pressure steam turbine through a pipeline, and the high-pressure steam flowing through the high-pressure steam turbine will be further used as steam supplement for the low-pressure steam turbine after being converted into low-pressure steam, and the outlet of the low-pressure steam turbine is connected to the comprehensive utilization system of thermal energy; the high-pressure steam turbine and the low-pressure steam turbine are used to convert the thermal energy of steam into mechanical energy, and are connected by a transmission shaft, and the right side of the low-pressure steam turbine is connected to the generator, and the high-pressure steam turbine and the low-pressure steam turbine drive the generator to rotate to realize the power generation process; the right side of the generator is connected to the transformer to ensure the high voltage required by the power grid; the right end of the transformer is connected to the power grid and the compressed air energy storage system, and the surplus electric energy during low-peak electricity consumption will be handed over to the compressed air energy storage system for storage in the form of high-pressure gas.

2. The adjustable hot dry rock thermoelectric coupling cascade utilization system based on compressed air energy storage according to claim 1 is characterized in that: The hot dry rock mining system includes: a mining well, an injection well, a mining water pump and an injection water pump; the mining well and the injection well reserve a pump chamber section of not less than 500m; the left end of the injection water pump is connected to the tailwater treatment system through a pipeline, and is used to inject the working fluid into the hot dry rock reservoir through the injection well; the left end of the mining water pump is connected to the production well, and is used to extract the working fluid heated by the hot dry rock reservoir from the reservoir; the right end is connected to the geothermal power generation system through a pipeline, and is used to pump the high-temperature fluid to the geothermal power generation system.

3. The adjustable hot dry rock thermoelectric coupling cascade utilization system based on compressed air energy storage according to claim 2 is characterized in that: The comprehensive utilization system of heat energy includes a three-way valve, a primary plate heat exchanger, a secondary plate heat exchanger, a tertiary plate heat exchanger, a primary heat collection module, a secondary heat collection module, a tertiary heat collection module and three user-end water pumps; both ends of the primary plate heat exchanger are connected to the main pipeline, the heat exchange end is connected to the primary heat collection module and the user-end water pump, the primary heat collection module is used for household heating or bathing, and the user-end water pump is used to maintain water circulation; both ends of the secondary plate heat exchanger are connected to the main pipeline, the heat exchange end is connected to the secondary heat collection module and the user-end water pump, and the secondary heat collection module is used for industrial production; both ends of the tertiary plate heat exchanger are connected to the main pipeline, connected to the tertiary heat collection module and the user-end water pump, and the tertiary heat collection module is used for agricultural and aquaculture production; the left side of the main pipeline is connected to the tail water treatment system.

4. The adjustable hot dry rock thermoelectric coupling cascade utilization system based on compressed air energy storage according to claim 3 is characterized in that: The tailwater treatment system includes: a water purification device and a water storage device; the upper side of the water purification device is connected to the main pipeline for treating a large amount of mineral ions in the tailwater; the upper side of the water storage device is connected to the water purification device for receiving and storing the working fluid, and then the working fluid is injected into the hot dry rock reservoir by the injection pump on the right side to realize the extraction cycle.

5. The adjustable hot dry rock thermoelectric coupling cascade utilization system based on compressed air energy storage according to claim 4 is characterized in that: The temperature of the low-temperature fluid itself is higher than that of the working fluid. After the high-temperature fluid flows through the geothermal power generation system, part of its heat energy is used to generate electricity. Subsequently, the low-temperature fluid with a temperature lower than that of the high-temperature fluid flows through the comprehensive thermal energy utilization system for secondary heat recovery.

6. The adjustable hot dry rock thermoelectric coupling cascade utilization system based on compressed air energy storage according to claim 5 is characterized in that: The pump chamber sections at the upper ends of the production well and the injection well are reinforced with high temperature resistant and corrosion resistant cement materials.

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