An energy storage system and operation method based on thermochemical energy storage and Brayton cycle

Abstract

This invention relates to the field of energy storage technology, providing an energy storage system and its operation method based on thermochemical energy storage and the Brayton cycle. The energy storage system includes a storage device and an energy storage unit. The energy storage unit includes a calcium hydroxide calcination reactor, a first heat exchange network, a first regenerator, a first compressor, a first turbine, a first motor, and a first generator, with each component connected sequentially. The first motor drives the first compressor, which compresses carbon dioxide to a high-temperature, high-pressure state, converting electrical energy into heat energy. The high-temperature, high-pressure carbon dioxide heats the calcium hydroxide solid particles, causing the calcium hydroxide to decompose into calcium oxide solid particles and water vapor, converting heat energy into chemical energy. The energy storage system provided by this invention serves as a comprehensive energy storage platform, realizing the conversion, transfer, and storage of electrical energy, heat energy, and chemical energy. It boasts high energy conversion efficiency and can provide end-users with integrated cooling, heating, and power energy services.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, and in particular to an energy storage system and its operation method based on thermochemical energy storage and Brayton cycle. Background Technology

[0002] Carnot batteries, also known as heat pump energy storage technology, are an energy storage technology capable of storing GWh of electricity. Compared with traditional technologies such as compressed air energy storage and pumped hydro storage, Carnot batteries have advantages such as not relying on fossil fuels, not being constrained by geographical conditions, and providing integrated cooling, heating, and power energy services. Typically, Carnot batteries utilize heat pump cycles such as Brayton heat pumps or vapor compression heat pumps to convert electrical energy into heat energy during the energy storage phase, storing the heat energy in thermal and cold storage tanks; during the energy release phase, the stored heat or cold energy is converted into electrical energy through power cycles such as Brayton heat engines or Rankine cycles. However, existing Carnot batteries are mostly based on sensible or latent heat materials for energy storage, resulting in low energy density and significant heat dissipation over long storage periods.

[0003] Thermochemical energy storage utilizes the thermal effects of reversible chemical reactions to store and release heat. Compared to sensible and latent heat storage methods, it offers advantages such as high energy density and suitability for long-term storage. For example, the energy density of calcium oxide and calcium hydroxide working fluid pairs is 500-600 kWh / ton, approximately three times that of molten salt and ten times that of hot water, and the storage process requires no insulation. However, existing thermochemical energy storage technologies suffer from low heat and mass transfer efficiency and poor maintainability, limiting their long-term stable and efficient operation. Summary of the Invention

[0004] This invention provides an energy storage system based on thermochemical energy storage and the Brayton cycle, which effectively realizes the conversion, transmission and storage between electrical energy, thermal energy and chemical energy. The energy conversion efficiency is high during the energy conversion and transmission process, and it can provide end users with integrated cooling, heating and power energy services, thereby improving the safety and flexibility of the new power system based on renewable energy.

[0005] The present invention also provides an operation method for an energy storage system based on thermochemical energy storage and Brayton cycle.

[0006] An energy storage system based on thermochemical energy storage and Brayton cycle, provided according to a first aspect embodiment of the present invention, includes:

[0007] Storage devices;

[0008] An energy storage device includes a calcium hydroxide calcination reactor, a first heat exchange network, a first regenerator, a first compressor, a first turbine, a first motor, and a first generator. The calcium hydroxide inlet of the calcium hydroxide calcination reactor is connected to the calcium hydroxide outlet of the first heat exchange network, the calcium oxide outlet of the calcium hydroxide calcination reactor is connected to the calcium oxide inlet of the first heat exchange network, and the steam outlet of the calcium hydroxide calcination reactor is connected to the steam inlet of the first heat exchange network. The water outlet, calcium hydroxide inlet, and calcium oxide outlet of the first heat exchange network are all connected to the storage device. The first inlet of the first regenerator is connected to the carbon dioxide outlet of the calcium hydroxide calcination reactor. The first compressor is connected in series between the first outlet of the first regenerator and the carbon dioxide inlet of the calcium hydroxide calcination reactor. The first turbine is connected in series between the second outlet and the second inlet of the first regenerator. The shaft of the first motor is connected to the first compressor, and the shaft of the first generator is connected to the first turbine.

[0009] According to the present invention, an energy storage system based on thermochemical energy storage and Brayton cycle is provided, wherein the energy storage device further includes:

[0010] A first cyclone separator is connected in series between the steam outlet of the calcium hydroxide calcination reactor and the steam inlet of the first heat exchange network.

[0011] According to the present invention, an energy storage system based on thermochemical energy storage and Brayton cycle is provided, wherein the energy storage device further includes:

[0012] An industrial waste heat exchanger, wherein the first inlet of the industrial waste heat exchanger is connected to the outlet of the first turbine, and the first outlet of the industrial waste heat exchanger is connected to the second inlet of the first regenerator.

[0013] An industrial waste heat supply unit, wherein the outlet of the industrial waste heat supply unit is connected to the second inlet of the industrial waste heat exchanger, and the inlet of the industrial waste heat supply unit is connected to the second outlet of the industrial waste heat exchanger.

[0014] According to the present invention, an energy storage system based on thermochemical energy storage and Brayton cycle is provided, wherein the storage device comprises:

[0015] A room temperature water storage tank, wherein the inlet of the room temperature water storage tank is connected to the water outlet of the first heat exchange network;

[0016] A calcium hydroxide storage tank, wherein the calcium hydroxide outlet of the calcium hydroxide storage tank is connected to the calcium hydroxide inlet of the first heat exchange network;

[0017] A calcium oxide storage tank, wherein the calcium oxide inlet of the calcium oxide storage tank is connected to the calcium oxide outlet of the first heat exchange network.

[0018] An energy storage system based on thermochemical energy storage and Brayton cycle according to the present invention further includes:

[0019] The energy release device includes a water preheating heat exchanger, a steam generator, a second heat exchanger network, a calcium oxide hydration reaction fluidized bed, a second regenerator, a second compressor, a second turbine, a second motor, and a second generator. The first inlet of the water preheating heat exchanger is connected to the outlet of the ambient temperature water storage tank, and the first outlet of the water preheating heat exchanger is connected to the inlet of the steam generator. The steam outlets of the steam generator and the calcium oxide hydration reaction fluidized bed are both connected to the steam inlet of the second heat exchanger network. The calcium hydroxide outlet of the second heat exchanger network is connected to the calcium hydroxide inlet of the calcium hydroxide storage tank, and the calcium oxide inlet of the second heat exchanger network is connected to the calcium oxide outlet of the calcium oxide storage tank. The carbon dioxide inlet of the second heat exchanger network is connected to the second regenerator. The first outlet of the second heat exchanger network is connected to the second turbine, which is connected in series between the carbon dioxide outlet of the second heat exchanger network and the first inlet of the second regenerator. The calcium oxide outlet of the second heat exchanger network is connected to the calcium oxide inlet of the calcium oxide hydration reaction fluidized bed. The steam outlet of the second heat exchanger network is connected to the steam inlet of the calcium oxide hydration reaction fluidized bed. The calcium hydroxide inlet of the second heat exchanger network is connected to the calcium hydroxide outlet of the calcium oxide hydration reaction fluidized bed. The second compressor is connected in series between the second outlet of the water preheating heat exchanger and the second inlet of the second regenerator. The second inlet of the water preheating heat exchanger is connected to the second outlet of the second regenerator. The shaft of the second motor is connected to the second compressor, and the shaft of the second generator is connected to the second turbine.

[0020] According to the present invention, an energy storage system based on thermochemical energy storage and Brayton cycle is provided, wherein the energy release device further includes:

[0021] A heating heat exchanger, wherein the first inlet of the heating heat exchanger is connected to the second outlet of the second regenerator, the first outlet of the heating heat exchanger is connected to the second inlet of the water preheating heat exchanger, the second inlet of the heating heat exchanger is connected to the outlet of the end user through a first pipeline, and the second outlet of the heating heat exchanger is connected to the inlet of the end user through a second pipeline;

[0022] An absorption heat pump, wherein the first port of the absorption heat pump is connected to the first pipeline through a first valve, the second port of the absorption heat pump is connected to the first pipeline through a second valve, the third port of the absorption heat pump is connected to the second pipeline through a third valve, and the fourth port of the absorption heat pump is connected to the second pipeline through a fourth valve.

[0023] According to the present invention, an energy storage system based on thermochemical energy storage and Brayton cycle is provided, wherein the energy release device further includes:

[0024] The second cyclone separator has its steam inlet connected to the steam outlet of the calcium oxide hydration reaction fluidized bed. The steam outlet of the second cyclone separator and the steam outlet of the steam generator are both connected to the steam inlet of the second heat exchanger network.

[0025] According to the present invention, an energy storage system based on thermochemical energy storage and Brayton cycle is provided, wherein the energy release device further includes:

[0026] A steam mixer, wherein the steam inlet of the steam mixer is connected to the steam outlet of the second cyclone separator and the steam outlet of the steam generator, and the steam outlet of the steam mixer is connected to the steam inlet of the second heat exchanger network.

[0027] According to a second aspect of the present invention, an operation method for an energy storage system based on thermochemical energy storage and Brayton cycle is provided, the operation method being based on the energy storage system based on thermochemical energy storage and Brayton cycle described in any one of the preceding claims, the operation method comprising:

[0028] The excess power of the power grid is used to drive the first motor to rotate, and the first motor drives the first compressor to work, so as to compress supercritical carbon dioxide to a high temperature and high pressure state.

[0029] High-temperature and high-pressure supercritical carbon dioxide is introduced into a calcium hydroxide calcination reactor to heat the calcium hydroxide, causing the calcium hydroxide to decompose into calcium oxide solid particles and water vapor.

[0030] The calcium hydroxide entering the calcium hydroxide calcination reactor is preheated by utilizing the residual heat carried by the calcium oxide solid particles and water vapor through the first heat exchange network.

[0031] The operation method of an energy storage system based on thermochemical energy storage and Brayton cycle provided by the present invention further includes:

[0032] Calcium oxide solid particles are reacted with water vapor in a calcium oxide hydration fluidized bed to produce calcium hydroxide.

[0033] Room temperature supercritical carbon dioxide is fed into the second compressor for heating and pressurization;

[0034] The carbon dioxide, after being heated and pressurized by the second compressor, is sequentially fed into the second regenerator and the second heat exchanger network to obtain high-temperature and high-pressure supercritical carbon dioxide.

[0035] High-temperature, high-pressure supercritical carbon dioxide is input into the second turbine to make the second turbine operate and drive the second generator to generate electricity.

[0036] Medium-temperature supercritical carbon dioxide is fed into a heat exchanger, and the waste heat from the reaction is used to provide heating or cooling to end users.

[0037] The above-described one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects:

[0038] The energy storage system based on thermochemical energy storage and the Brayton cycle provided by the present invention uses a first motor to drive a first compressor. The first compressor compresses carbon dioxide to a high-temperature, high-pressure state, converting electrical energy into heat energy. The heat from the high-temperature, high-pressure carbon dioxide heats calcium hydroxide solid particles, causing the calcium hydroxide to decompose into calcium oxide solid particles and water vapor, converting the heat energy into chemical energy suitable for long-term storage. As a comprehensive energy storage platform, the energy storage system provided by the present invention realizes the conversion, transfer, and storage of electrical energy, heat energy, and chemical energy. It exhibits high energy conversion efficiency during the energy conversion and transfer process, providing end users with integrated energy services including cooling, heating, and electricity, and improving the security and flexibility of the new power system based on renewable energy.

[0039] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of the structure of an energy storage system based on thermochemical energy storage and Brayton cycle provided in an embodiment of the present invention;

[0042] Figure 2 This is a schematic diagram of the connection structure between the energy storage device and the storage device provided in an embodiment of the present invention;

[0043] Figure 3This is a schematic diagram of the connection structure between the energy release device and the storage device provided in an embodiment of the present invention;

[0044] Figure 4 This is a schematic flowchart of the operation method of an energy storage system based on thermochemical energy storage and Brayton cycle provided in an embodiment of the present invention.

[0045] Figure label:

[0046] 1. First regenerator; 2. Calcium hydroxide calcination reactor; 3. First cyclone separator; 4. First heat exchange network; 5. Ambient temperature water storage tank; 6. Calcium hydroxide storage tank; 7. Calcium oxide storage tank; 8. First compressor; 9. First turbine; 10. First motor; 11. First generator; 12. Industrial waste heat exchanger; 13. Industrial waste heat supply unit; 14. Water preheating heat exchanger; 15. Steam generator; 16. Second cyclone separator; 17. Steam mixer; 18. Second heat exchanger network; 19. Calcium oxide hydration reaction fluidized bed; 20. Second regenerator; 21. Second compressor; 22. Second turbine; 23. Second motor; 24. Second generator; 25. Heating heat exchanger; 26. Absorption heat pump; 27. First valve; 28. Second valve; 29. ​​Third valve; 30. Fourth valve; 31. End user. Detailed Implementation

[0047] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0048] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0049] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0050] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0051] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0052] The following is combined with Figures 1 to 3 This invention describes an energy storage system based on thermochemical energy storage and the Brayton cycle, provided by an embodiment of the present invention.

[0053] Figure 1 A schematic diagram of the structure of an energy storage system based on thermochemical energy storage and Brayton cycle provided in an embodiment of the present invention is illustrated. Figure 2 A schematic diagram illustrating the connection structure between the energy storage device and the storage device provided in an embodiment of the present invention is shown, such as... Figure 1 and Figure 2 As shown, the energy storage system based on thermochemical energy storage and Brayton cycle includes storage devices and energy storage equipment. The energy storage equipment includes a calcium hydroxide calcination reactor 2, a first heat exchange network 4, a first regenerator 1, a first compressor 8, a first turbine 9, a first motor 10, and a first generator 11.

[0054] The water outlet, calcium hydroxide inlet, and calcium oxide outlet of the first heat exchange network 4 are all connected to the storage device. Solid calcium hydroxide particles from the storage device are transported into the first heat exchange network 4 through the calcium hydroxide inlet. The solid calcium hydroxide particles absorb heat from the high-temperature calcium oxide particles and high-temperature water vapor within the first heat exchange network 4, thereby preheating the solid calcium hydroxide particles.

[0055] The calcium hydroxide inlet of the calcium hydroxide calcination reactor 2 is connected to the calcium hydroxide outlet of the first heat exchange network 4. After the calcium hydroxide solid particles are preheated by the first heat exchange network 4, they enter the calcium hydroxide calcination reactor 2 from the calcium hydroxide inlet. The calcium hydroxide calcination reactor 2 is used to decompose the calcium hydroxide solid particles and generate high-temperature calcium oxide solid particles and high-temperature water vapor.

[0056] The calcium oxide outlet of the calcium hydroxide calcination reactor 2 is connected to the calcium oxide inlet of the first heat exchange network 4. High-temperature calcium oxide solid particles enter the first heat exchange network 4 through this connection. The steam outlet of the calcium hydroxide calcination reactor 2 is also connected to the steam inlet of the first heat exchange network 4. High-temperature steam enters the first heat exchange network 4 through this connection. The residual heat carried by the calcium oxide solid particles and steam is used to preheat the calcium hydroxide before it enters the calcination reactor 2. After transferring heat to the calcium hydroxide solid particles, the high-temperature steam is cooled to room-temperature liquid water. The calcium oxide solid particles and the cooled room-temperature liquid water are then transported back to the storage device, completing the thermochemical energy storage process.

[0057] The first inlet of the first regenerator 1 is connected to the carbon dioxide outlet of the calcium hydroxide calcination reactor 2. The first compressor 8 is connected in series between the first outlet of the first regenerator 1 and the carbon dioxide inlet of the calcium hydroxide calcination reactor 2; that is, the inlet of the first compressor 8 is connected to the first outlet of the first regenerator 1, and the outlet of the first compressor 8 is connected to the carbon dioxide inlet of the calcium hydroxide calcination reactor 2. The shaft of the first motor 10 is connected to the first compressor 8. Excess power from the power grid drives the first motor 10 to rotate, which in turn drives the first compressor 8 to compress the supercritical carbon dioxide gas flow to a high temperature and high pressure state, thus converting electrical energy into heat energy. The pressure of the supercritical carbon dioxide gas flowing out of the outlet of the first compressor 8 is 20-30 MPa, and the temperature is 600-650℃.

[0058] High-temperature, high-pressure supercritical carbon dioxide gas flows into the high-temperature carbon dioxide heating jacket from the carbon dioxide inlet of the calcium hydroxide calcination reactor 2. The heat carried by the carbon dioxide is transferred to the calcium hydroxide solid particles in the calcination furnace through conduction, convection, and radiation, causing the calcium hydroxide solid particles to decompose into high-temperature calcium oxide solid particles and high-temperature water vapor. The high-temperature, high-pressure supercritical carbon dioxide gas flows into the first regenerator 1 through the carbon dioxide outlet of the calcium hydroxide calcination reactor 2 and the first inlet of the first regenerator 1, where it exchanges heat with the supercritical carbon dioxide gas in the first regenerator 1. Subsequently, the high-temperature, high-pressure supercritical carbon dioxide gas flows out from the second outlet of the first regenerator 1.

[0059] The first turbine 9 is connected in series between the second outlet and the second inlet of the first regenerator 1, meaning the inlet of the first turbine 9 is connected to the second outlet of the first regenerator 1, and the outlet of the first turbine 9 is connected to the second inlet of the first regenerator 1. The shaft of the first generator 11 is connected to the first turbine 9. Supercritical carbon dioxide gas flowing from the second outlet of the first regenerator 1 flows into the first turbine 9, driving the first turbine 9 to perform work, which in turn drives the first generator 11 to generate electricity, thus converting thermal energy into electrical energy. The electricity generated by the first generator 11 is used to drive the first motor 10 to rotate. The supercritical carbon dioxide gas flowing from the outlet of the first turbine 9 enters the first regenerator 1 through the second inlet. After being heated once in the first regenerator 1, the supercritical carbon dioxide gas flows out from the first outlet of the first regenerator 1 and enters the first compressor 8 through the inlet. The first compressor 8 compresses the supercritical carbon dioxide gas to a high temperature and high pressure state, thereby completing the Brayton cycle of supercritical carbon dioxide.

[0060] According to the embodiment of the present invention, the energy storage system based on thermochemical energy storage and Brayton cycle is provided. The first motor 10 drives the first compressor 8, which compresses carbon dioxide to a high temperature and high pressure state, converting electrical energy into heat energy. The heat of the high temperature and high pressure carbon dioxide heats the calcium hydroxide solid particles, causing the calcium hydroxide to decompose into calcium oxide solid particles and water vapor, converting the heat energy into chemical energy suitable for long-term storage.

[0061] In an embodiment of the present invention, the first heat exchange network 4 includes a set of fluid-solid heat exchangers, fluid-fluid heat exchangers, and connecting pipelines. The specific pipeline composition can be designed using pinch analysis based on the mass heat capacity and temperature of the inlet and outlet materials. The first heat exchange network 4 is existing equipment, and its specific structure will not be described in detail here.

[0062] In an embodiment of the present invention, the structure of the calcium hydroxide calcination reactor 2, from the outside to the inside, consists of a heat insulation layer, a high-pressure resistant shell, a high-temperature carbon dioxide heating jacket, and a calcium hydroxide solid particle calcination furnace body. The high-temperature carbon dioxide heating jacket is connected to the carbon dioxide inlet of the calcium hydroxide calcination reactor 2.

[0063] The calcium hydroxide inlet is located at the top of the calcium hydroxide calcination reactor 2, the calcium oxide outlet is located at the bottom of the calcium hydroxide calcination reactor 2, and the steam outlet is located at the top of the calcium hydroxide calcination reactor 2.

[0064] In an embodiment of the present invention, the energy storage device further includes a first cyclone separator 3, which is connected in series between the steam outlet of the calcium hydroxide calcination reactor 2 and the steam inlet of the first heat exchange network 4. Specifically, the inlet of the first cyclone separator 3 is connected to the steam outlet of the calcium hydroxide calcination reactor 2, and the outlet of the first cyclone separator 3 is connected to the steam inlet of the first heat exchange network 4. The high-temperature steam output from the calcium hydroxide calcination reactor 2 enters the first cyclone separator 3, which separates the solid particles or powder carried by the high-temperature steam to obtain impurity-free high-temperature steam.

[0065] In embodiments of the present invention, such as Figure 1 and Figure 2 As shown, the energy storage device also includes an industrial waste heat exchanger 12 and an industrial waste heat supply unit 13. The first inlet of the industrial waste heat exchanger 12 is connected to the outlet of the first turbine 9, and the first outlet of the industrial waste heat exchanger 12 is connected to the second inlet of the first regenerator 1. The outlet of the industrial waste heat supply unit 13 is connected to the second inlet of the industrial waste heat exchanger 12, and the inlet of the industrial waste heat supply unit 13 is connected to the second outlet of the industrial waste heat exchanger 12. The supercritical carbon dioxide gas flow from the first turbine 9 passes through the industrial waste heat exchanger 12, absorbing industrial waste heat at a temperature of 200-300℃, thus realizing the utilization of industrial waste heat resources.

[0066] In an embodiment of the present invention, the storage device includes a room temperature water storage tank 5, a calcium hydroxide storage tank 6, and a calcium oxide storage tank 7. The calcium hydroxide outlet of the calcium hydroxide storage tank 6 is connected to the calcium hydroxide inlet of the first heat exchange network 4, and the calcium hydroxide storage tank 6 provides solid calcium hydroxide particles to the first heat exchange network 4. The inlet of the room temperature water storage tank 5 is connected to the water outlet of the first heat exchange network 4, and cooled room temperature liquid water enters the room temperature water storage tank 5 for storage. The calcium oxide inlet of the calcium oxide storage tank 7 is connected to the calcium oxide outlet of the first heat exchange network 4, and room temperature solid calcium oxide particles enter the calcium oxide storage tank 7 to complete the storage of calcium oxide, thus completing the thermochemical energy storage process. Both the calcium hydroxide storage tank 6 and the calcium oxide storage tank 7 are sealed storage containers.

[0067] When there is a demand for excess electricity, the energy storage equipment is activated to convert the excess electrical energy and industrial waste heat into high-grade thermal energy, which is then stored in calcium oxide solid particles in the form of chemical energy for a long period of time.

[0068] In an embodiment of the present invention, Figure 3 A schematic diagram illustrating the connection structure between the energy release device and the storage device provided in an embodiment of the present invention is shown, such as... Figure 1 and Figure 3As shown, the energy storage system also includes energy release devices, which include a water preheating heat exchanger 14, a steam generator 15, a second heat exchanger network 18, a calcium oxide hydration reaction fluidized bed 19, a second regenerator 20, a second compressor 21, a second turbine 22, a second motor 23, and a second generator 24.

[0069] The first inlet of the water preheating heat exchanger 14 is connected to the outlet of the ambient temperature water storage tank 5, and the first outlet of the water preheating heat exchanger 14 is connected to the inlet of the steam generator 15. Ambient temperature liquid water is pumped from the ambient temperature water storage tank 5 into the water preheating heat exchanger 14 for preheating, and then enters the steam generator 15 to generate steam. The steam outlet of the steam generator 15 and the steam outlet of the calcium oxide hydration reaction fluidized bed 19 are both connected to the steam inlet of the second heat exchanger network 18. The steam enters the second heat exchanger network 18 from the steam inlet, further increasing the temperature of the steam. The steam outlet of the second heat exchanger network 18 is connected to the steam inlet of the calcium oxide hydration reaction fluidized bed 19, and after the temperature is increased, the steam flows into the calcium oxide hydration reaction fluidized bed 19 from the steam inlet.

[0070] The calcium oxide inlet of the second heat exchanger network 18 is connected to the calcium oxide outlet of the calcium oxide storage tank 7. Room-temperature calcium oxide solid particles from the storage tank 7 are transported into the second heat exchanger network 18 via the calcium oxide inlet, where they undergo preheating. The calcium oxide outlet of the second heat exchanger network 18 is connected to the calcium oxide inlet of the calcium oxide hydration reaction fluidized bed 19. The preheated calcium oxide solid particles enter the hydration reaction fluidized bed 19 through the calcium oxide inlet, where they undergo a hydration reaction with the water vapor. This hydration reaction converts the chemical energy within the calcium oxide into heat energy, releasing high-temperature heat and yielding high-temperature calcium hydroxide solid particles.

[0071] It should be noted that the calcium oxide inlet of the calcium oxide hydration reaction fluidized bed 19 is located above the water vapor outlet of the calcium oxide hydration reaction fluidized bed 19. After the calcium oxide solid particles enter the calcium oxide hydration reaction fluidized bed 19, they are in a fluidized state, which allows the calcium oxide solid particles to react fully with the water vapor to generate calcium hydroxide solid particles.

[0072] It should also be noted that the hydration reaction operates at a pressure of 0.1-7 MPa, corresponding to a reaction temperature of 500-600℃. The calcium oxide hydration reaction fluidized bed 19 includes structures such as a heat insulation layer, a shell, and a furnace body. Since the calcium oxide hydration reaction fluidized bed 19 is existing equipment, its specific structure will not be described in detail here.

[0073] The calcium hydroxide inlet of the second heat exchanger network 18 is connected to the calcium hydroxide outlet of the calcium oxide hydration reaction fluidized bed 19. High-temperature calcium hydroxide solid particles flow out from the calcium hydroxide outlet of the calcium oxide hydration reaction fluidized bed 19 and enter the second heat exchanger network 18 through the calcium hydroxide inlet. The calcium hydroxide outlet of the second heat exchanger network 18 is connected to the calcium hydroxide inlet of the calcium hydroxide storage tank 6. The high-temperature calcium hydroxide solid particles release heat in the second heat exchanger network 18. After releasing heat, the calcium hydroxide solid particles are transported back to the calcium hydroxide storage tank 6 for storage, completing the thermochemical energy release cycle.

[0074] It should be noted that during operation, some calcium hydroxide solid particles experience reduced reactivity and mechanical properties due to high-temperature sintering, crushing, and sedimentation, resulting in a decrease in the inventory of calcium hydroxide solid particles. To maintain the long-term stability of thermochemical energy storage and release cycles, a small portion of fresh calcium hydroxide solid particles can be added to the calcium hydroxide storage tank 6 each time they are transported into the first heat exchange network 4, allowing them to enter the first heat exchange network 4 together with the existing particles for preheating. Simultaneously, some old calcium hydroxide solid particles in the calcium hydroxide storage tank 6 should be periodically removed. The calcium hydroxide solid particles are modified with a high-temperature binder, possessing strong mechanical properties and anti-agglomeration characteristics, with a particle diameter of 100-1000 μm.

[0075] The second turbine 22 is connected in series between the carbon dioxide outlet of the second heat exchanger network 18 and the first inlet of the second regenerator 20. That is, the inlet of the second turbine 22 is connected to the carbon dioxide outlet of the second heat exchanger network 18, and the outlet of the second turbine 22 is connected to the first inlet of the second regenerator 20. The medium-temperature supercritical carbon dioxide gas flow at the outlet of the second turbine 22 enters the second regenerator 20 through the first inlet of the second regenerator 20. The medium-temperature supercritical carbon dioxide gas flow completes heat transfer within the second regenerator 20, and the temperature of the medium-temperature supercritical carbon dioxide gas flow decreases to 100-140℃ within the second regenerator 20.

[0076] The second inlet of the water preheating heat exchanger 14 is connected to the second outlet of the second regenerator 20. The medium-temperature supercritical carbon dioxide gas flows out from the second outlet of the second regenerator 20 and enters the water preheating heat exchanger 14. The heat of the medium-temperature supercritical carbon dioxide gas heats the room temperature water in the water preheating heat exchanger 14, and the medium-temperature supercritical carbon dioxide gas is converted into room temperature supercritical carbon dioxide gas, and the temperature drops to 30-40℃.

[0077] The second compressor 21 is connected in series between the second outlet of the water preheating heat exchanger 14 and the second inlet of the second regenerator 20. Specifically, the inlet of the second compressor 21 is connected to the second outlet of the water preheating heat exchanger 14, and the outlet of the second compressor 21 is connected to the second inlet of the second regenerator 20. The shaft of the second motor 23 is connected to the second compressor 21. Ambient temperature supercritical carbon dioxide gas flows through the second outlet of the water preheating heat exchanger 14 and the inlet of the second compressor 21 into the second compressor 21. Driven by the second motor 23, the second compressor 21 heats and pressurizes the ambient temperature supercritical carbon dioxide gas, resulting in a supercritical carbon dioxide gas pressure of 20-30 MPa at the outlet of the second compressor 21. The heated and pressurized supercritical carbon dioxide gas then enters the second regenerator 20 through the second inlet, absorbing heat from the intermediate temperature supercritical carbon dioxide gas within the second regenerator 20.

[0078] The carbon dioxide inlet of the second heat exchanger network 18 is connected to the first outlet of the second regenerator 20. After the supercritical carbon dioxide gas flow is heated and pressurized, its temperature is further increased by the second regenerator 20, and then it enters the second heat exchanger network 18 from the carbon dioxide inlet. It further absorbs heat in the second heat exchanger network 18 to obtain a high-temperature and high-pressure supercritical carbon dioxide gas flow. At this time, the temperature of the carbon dioxide gas flow rises to 480-580℃.

[0079] High-temperature, high-pressure supercritical carbon dioxide gas flows out from the carbon dioxide outlet of the second heat exchanger network 18 and enters the second turbine 22. The high-temperature, high-pressure supercritical carbon dioxide gas drives the second turbine 22 to expand and do work, with the expansion outlet pressure being 7.5 MPa. The shaft of the second generator 24 is connected to the second turbine 22, and the second turbine 22 drives the second generator 24 to generate electricity, thereby converting thermal energy into electrical energy and completing the Brayton heat engine cycle.

[0080] In an embodiment of the present invention, the energy release device further includes a second cyclone separator 16. The steam inlet of the second cyclone separator 16 is connected to the steam outlet of the calcium oxide hydration reaction fluidized bed 19. Excess steam after the hydration reaction flows into the second cyclone separator 16 via the steam outlet of the calcium oxide hydration reaction fluidized bed 19 and the steam inlet of the second cyclone separator 16. The second cyclone separator 16 separates the solid particles or powder carried by the high-temperature steam to obtain impurity-free high-temperature steam. The steam outlet of the second cyclone separator 16 and the outlet of the steam generator 15 are both connected to the steam inlet of the second heat exchanger network 18.

[0081] In an embodiment of the present invention, the energy release device further includes a steam mixer 17. The steam inlet of the steam mixer 17 is connected to both the steam outlet of the second cyclone separator 16 and the steam outlet of the steam generator 15. The steam outlet of the steam mixer 17 is connected to the steam inlet of the second heat exchanger network 18. The steam generated by the steam generator 15 and the impurity-free high-temperature steam obtained from the separation by the second cyclone separator 16 are mixed in the steam mixer 17. The mixed steam then enters the second heat exchanger network 18 through its steam inlet, further increasing the steam temperature.

[0082] In an embodiment of the present invention, the energy release device further includes a heating heat exchanger 25. The first inlet of the heating heat exchanger 25 is connected to the second outlet of the second regenerator 20, and the first outlet of the heating heat exchanger 25 is connected to the second inlet of the water preheating heat exchanger 14. The mesotemperature supercritical carbon dioxide gas flows into the heating heat exchanger 25 through the second outlet of the second regenerator 20 and the first inlet of the heating heat exchanger 25. After heat exchange is completed within the heating heat exchanger 25, the gas flows out from the first outlet of the heating heat exchanger 25 and enters the water preheating heat exchanger 14, further reducing the temperature of the mesotemperature supercritical carbon dioxide gas. At the second outlet of the water preheating heat exchanger 14, the temperature of the supercritical carbon dioxide fluid decreases to 30-40°C.

[0083] The second inlet of the heat exchanger 25 is connected to the outlet of the end user 31 via the first pipe, and the second outlet of the heat exchanger 25 is connected to the inlet of the end user 31 via the second pipe. The heating return water required by the end user 31 flows into the heat exchanger 25 through the first pipe and the second inlet of the heat exchanger 25. After absorbing heat from the medium-temperature supercritical carbon dioxide gas flow inside the heat exchanger 25, the temperature of the heating return water rises to 60-70℃. Furthermore, after absorbing heat, the heating return water flows to the end user 31 through the second outlet and the second pipe of the heat exchanger 25, meeting the heating needs of the end user 31.

[0084] When there are demand scenarios for grid peak shaving and user heating, the energy release device is activated to convert the chemical energy in the calcium oxide solid particles into high-grade heat energy to drive power generation. At the same time, with the help of the heating function of the energy storage system, the waste heat from the reaction is used for heating of end users.

[0085] In an embodiment of the present invention, the energy release device further includes an absorption heat pump 26. The first port of the absorption heat pump 26 is connected to a first pipeline via a first valve 27, the second port of the absorption heat pump 26 is connected to the first pipeline via a second valve 28, the third port of the absorption heat pump 26 is connected to the second pipeline via a third valve 29, and the fourth port of the absorption heat pump 26 is connected to the second pipeline via a fourth valve 30. When the end user 31 needs cooling, the first valve 27, the second valve 28, the third valve 29, and the fourth valve 30 are opened. The working fluid in the absorption heat pump 26 enters the heat exchanger 25 through the first valve 27 and the first pipeline. The working fluid absorbs heat from the intermediate-temperature supercritical carbon dioxide gas flow in the heat exchanger 25. Subsequently, the working fluid carrying heat returns to the absorption heat pump 26 through the second pipeline and the third valve 29. The heated working fluid drives the absorption heat pump 26 to work. Under the action of the absorption heat pump 26, refrigeration is achieved and cooling water is obtained. The cooling water is transported to the end user 31 through the fourth valve 30 and the second pipeline to meet the cooling needs of the end user 31. After the temperature rises, the cooling water returns to the absorption heat pump 26 through the second valve 28 to achieve circulation.

[0086] When there are demand scenarios for grid peak shaving and user cooling, the energy release device is activated to convert the chemical energy in the calcium oxide solid particles into high-grade heat energy to drive power generation. At the same time, with the help of the cooling function of the energy storage system, the waste heat from the reaction is used for end-user cooling.

[0087] It should be noted that the number of heating heat exchangers 25 can be set to two. By distributing the supercritical carbon dioxide flow into the two heating heat exchangers 25, heating and cooling can be driven respectively, thereby realizing combined cooling, heating and power.

[0088] The following is combined with Figure 4 This invention describes an operation method for an energy storage system based on thermochemical energy storage and the Brayton cycle. Figure 4 A schematic flowchart illustrating the operation method of an energy storage system based on thermochemical energy storage and Brayton cycle provided in an embodiment of the present invention is shown below. Figure 4 As shown, the operation method of the energy storage system based on thermochemical energy storage and Brayton cycle provided by the present invention, based on the energy storage system based on thermochemical energy storage and Brayton cycle described in any of the above embodiments, includes the following steps:

[0089] Step 100: The excess power of the power grid is used to drive the first motor 10 to rotate. The first motor 10 drives the first compressor 8 to work, so as to compress the supercritical carbon dioxide to a high temperature and high pressure state.

[0090] The excess power from the power grid drives the first motor 10 to operate, which in turn drives the first compressor 8 to rotate. The first compressor 8 compresses the supercritical carbon dioxide gas flow to a high temperature and high pressure state, converting electrical energy into heat energy. The supercritical carbon dioxide gas flow out of the outlet of the first compressor 8 at a pressure of 20-30 MPa and a temperature of 600-650℃.

[0091] Step 200: High-temperature and high-pressure supercritical carbon dioxide is introduced into the calcium hydroxide calcination reactor 2 to heat the calcium hydroxide, causing the calcium hydroxide to decompose into calcium oxide solid particles and water vapor.

[0092] High-temperature and high-pressure supercritical carbon dioxide gas flowed into the calcium hydroxide calcining reactor 2 through the carbon dioxide inlet. The heat carried by the carbon dioxide was transferred to the calcium hydroxide solid particles in the calcium hydroxide calcining reactor 2 through heat conduction, convection and radiation, thereby heating the calcium hydroxide and causing the calcium hydroxide solid particles to decompose into high-temperature calcium oxide solid particles and high-temperature water vapor, thus converting the thermal energy carried by the carbon dioxide into the chemical energy of calcium oxide.

[0093] Step 300: The calcium hydroxide entering the calcium hydroxide calcination reactor 2 is preheated by using the residual heat carried by the calcium oxide solid particles and water vapor through the first heat exchange network 4.

[0094] High-temperature calcium oxide solid particles enter the first heat exchange network 4 through the calcium oxide outlet of the calcium hydroxide calcination reactor 2 and the calcium oxide inlet of the first heat exchange network 4; high-temperature steam enters the first heat exchange network 4 through the steam outlet of the calcium hydroxide calcination reactor 2 and the steam inlet of the first heat exchange network 4. The residual heat carried by the calcium oxide solid particles and steam is used to preheat the calcium hydroxide before it enters the calcium hydroxide calcination reactor 2. After preheating, the calcium hydroxide is fed into the calcium hydroxide calcination reactor 2, causing it to decompose and completing the thermochemical energy storage cycle.

[0095] In embodiments of the present invention, the operation method of the energy storage system further includes the following steps:

[0096] Step 400: Calcium oxide solid particles and water vapor are fed into the calcium oxide hydration reaction fluidized bed 19 to react and generate calcium hydroxide.

[0097] Steam generated by steam generator 15 and excess steam from calcium oxide hydration reaction fluidized bed 19 are mixed in steam mixer 17. The resulting high-temperature steam is then heated by a second heat exchanger network 18 before being fed into the calcium oxide hydration reaction fluidized bed 19. Calcium oxide solid particles from calcium oxide storage tank 7 are preheated by the second heat exchanger before being fed into the calcium oxide hydration reaction fluidized bed 19. The calcium oxide solid particles and steam undergo a hydration reaction within the calcium oxide hydration reaction fluidized bed 19, converting the chemical energy within the calcium oxide into heat energy, releasing high-temperature heat, and obtaining high-temperature calcium hydroxide solid particles. The high-temperature calcium hydroxide solid particles enter the second heat exchanger network 18 through the calcium hydroxide inlet.

[0098] Step 500: Introduce room temperature supercritical carbon dioxide into the second compressor 21 for heating and pressurization.

[0099] Step 600: The carbon dioxide, after being heated and pressurized by the second compressor 21, is sequentially input into the second regenerator 20 and the second heat exchanger network 18 to obtain high-temperature and high-pressure supercritical carbon dioxide.

[0100] Driven by the second motor 23, the second compressor 21 heats and pressurizes the ambient temperature supercritical carbon dioxide gas stream. The heated and pressurized supercritical carbon dioxide gas stream enters the second regenerator 20 through the second inlet, absorbing heat from the intermediate temperature supercritical carbon dioxide gas stream within the regenerator 20. After further temperature increases in the second regenerator 20, the heated and pressurized supercritical carbon dioxide gas stream enters the second heat exchanger network 18 through the carbon dioxide inlet, further absorbing heat from the network to obtain a high-temperature, high-pressure supercritical carbon dioxide gas stream.

[0101] Step 700: High-temperature and high-pressure supercritical carbon dioxide is input into the second turbine 22 to make the second turbine 22 operate and drive the second generator 24 to generate electricity.

[0102] High-temperature, high-pressure supercritical carbon dioxide gas flows out from the carbon dioxide outlet of the second heat exchanger network 18 and enters the second turbine 22. The high-temperature, high-pressure supercritical carbon dioxide gas drives the second turbine 22 to expand and do work, converting thermal energy into electrical energy. The shaft of the second generator 24 is connected to the second turbine 22, and the second turbine 22 drives the second generator 24 to generate electricity, thereby realizing the conversion of thermal energy into electrical energy and providing power energy services to the end user 31.

[0103] Step 800: Medium-temperature supercritical carbon dioxide is input into the heating heat exchanger 25, and the waste heat from the reaction is used to provide heating or cooling to the end user 31.

[0104] A medium-temperature supercritical carbon dioxide gas stream enters the heating heat exchanger 25 through its first inlet. When end user 31 requires heating, the heating return water enters the heating heat exchanger 25 through its second inlet. After absorbing heat from the medium-temperature supercritical carbon dioxide gas stream within the heating heat exchanger 25, the return water flows to end user 31 through the second outlet and second pipeline of the heating heat exchanger 25, meeting the heating needs of end user 31. When end user 31 requires cooling, the working fluid in the absorption heat pump 26 enters the heating heat exchanger 25 through the first valve 27. The working fluid absorbs heat from the medium-temperature supercritical carbon dioxide gas stream within the heating heat exchanger 25, and then returns to the absorption heat pump 26 carrying heat through the second pipeline and the third valve 29. The heated working fluid drives the absorption heat pump 26 to work, achieving cooling and obtaining cooling water. The cooling water is transported to the end user 31 through the fourth valve 30 and the second pipeline to meet the cooling needs of the end user 31. After the temperature rises, the cooling water returns to the absorption heat pump 26 through the second valve 28 to achieve circulation.

[0105] The operating method of the energy storage system based on thermochemical energy storage and Brayton cycle provided by this invention can realize the conversion, transfer and storage between electrical energy, chemical energy and thermal energy. Compared with the existing Carnot batteries for thermochemical energy storage, the system has less energy quantity and mass loss and higher thermoelectric conversion efficiency during operation. At the same time, it can utilize excess electricity from the power grid and low-temperature waste heat from industry, providing integrated regional energy services (cooling, heating and power) for end users 31.

[0106] The energy storage system based on thermochemical energy storage and Brayton cycle provided by this invention serves as a comprehensive energy storage platform, realizing the conversion, transmission, and storage between electrical energy, thermal energy, and chemical energy. It has high energy conversion efficiency during the energy conversion and transmission process and can provide end users 31 with comprehensive energy services including cooling, heating, and electricity, thereby improving the safety and flexibility of the new power system based on renewable energy.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An energy storage system based on thermochemical energy storage and Brayton cycle, characterized in that, include: The storage device includes a room temperature water storage tank, a calcium hydroxide storage tank, and a calcium oxide storage tank; the inlet of the room temperature water storage tank is connected to the water outlet of the first heat exchange network; the calcium hydroxide outlet of the calcium hydroxide storage tank is connected to the calcium hydroxide inlet of the first heat exchange network; and the calcium oxide inlet of the calcium oxide storage tank is connected to the calcium oxide outlet of the first heat exchange network. An energy storage device includes a calcium hydroxide calcination reactor, a first heat exchange network, a first regenerator, a first compressor, a first turbine, a first motor, and a first generator. The calcium hydroxide inlet of the calcium hydroxide calcination reactor is connected to the calcium hydroxide outlet of the first heat exchange network, the calcium oxide outlet of the calcium hydroxide calcination reactor is connected to the calcium oxide inlet of the first heat exchange network, and the steam outlet of the calcium hydroxide calcination reactor is connected to the steam inlet of the first heat exchange network. The water outlet, calcium hydroxide inlet, and calcium oxide outlet of the first heat exchange network are all connected to the storage device. The first inlet of the first regenerator is connected to the carbon dioxide outlet of the calcium hydroxide calcination reactor. The first compressor is connected in series between the first outlet of the first regenerator and the carbon dioxide inlet of the calcium hydroxide calcination reactor. The first turbine is connected in series between the second outlet and the second inlet of the first regenerator. The shaft of the first motor is connected to the first compressor, and the shaft of the first generator is connected to the first turbine. The energy release device includes a water preheating heat exchanger, a steam generator, a second heat exchanger network, a calcium oxide hydration reaction fluidized bed, a second regenerator, a second compressor, a second turbine, a second motor, and a second generator. The first inlet of the water preheating heat exchanger is connected to the outlet of the ambient temperature water storage tank, and the first outlet of the water preheating heat exchanger is connected to the inlet of the steam generator. The steam outlets of the steam generator and the calcium oxide hydration reaction fluidized bed are both connected to the steam inlet of the second heat exchanger network. The calcium hydroxide outlet of the second heat exchanger network is connected to the calcium hydroxide inlet of the calcium hydroxide storage tank, and the calcium oxide inlet of the second heat exchanger network is connected to the calcium oxide outlet of the calcium oxide storage tank. The carbon dioxide inlet of the second heat exchanger network is connected to the second regenerator. The first outlet of the second heat exchanger network is connected to the second turbine, which is connected in series between the carbon dioxide outlet of the second heat exchanger network and the first inlet of the second regenerator. The calcium oxide outlet of the second heat exchanger network is connected to the calcium oxide inlet of the calcium oxide hydration reaction fluidized bed. The steam outlet of the second heat exchanger network is connected to the steam inlet of the calcium oxide hydration reaction fluidized bed. The calcium hydroxide inlet of the second heat exchanger network is connected to the calcium hydroxide outlet of the calcium oxide hydration reaction fluidized bed. The second compressor is connected in series between the second outlet of the water preheating heat exchanger and the second inlet of the second regenerator. The second inlet of the water preheating heat exchanger is connected to the second outlet of the second regenerator. The shaft of the second motor is connected to the second compressor, and the shaft of the second generator is connected to the second turbine.

2. The energy storage system based on thermochemical energy storage and Brayton cycle according to claim 1, characterized in that, The energy storage device also includes: A first cyclone separator is connected in series between the steam outlet of the calcium hydroxide calcination reactor and the steam inlet of the first heat exchange network.

3. The energy storage system based on thermochemical energy storage and Brayton cycle according to claim 1, characterized in that, The energy storage device also includes: An industrial waste heat exchanger, wherein the first inlet of the industrial waste heat exchanger is connected to the outlet of the first turbine, and the first outlet of the industrial waste heat exchanger is connected to the second inlet of the first regenerator. An industrial waste heat supply unit, wherein the outlet of the industrial waste heat supply unit is connected to the second inlet of the industrial waste heat exchanger, and the inlet of the industrial waste heat supply unit is connected to the second outlet of the industrial waste heat exchanger.

4. The energy storage system based on thermochemical energy storage and Brayton cycle according to claim 1, characterized in that, The energy release device also includes: A heating heat exchanger, wherein the first inlet of the heating heat exchanger is connected to the second outlet of the second regenerator, the first outlet of the heating heat exchanger is connected to the second inlet of the water preheating heat exchanger, the second inlet of the heating heat exchanger is connected to the outlet of the end user through a first pipeline, and the second outlet of the heating heat exchanger is connected to the inlet of the end user through a second pipeline; An absorption heat pump, wherein the first port of the absorption heat pump is connected to the first pipeline through a first valve, the second port of the absorption heat pump is connected to the first pipeline through a second valve, the third port of the absorption heat pump is connected to the second pipeline through a third valve, and the fourth port of the absorption heat pump is connected to the second pipeline through a fourth valve.

5. The energy storage system based on thermochemical energy storage and Brayton cycle according to claim 1, characterized in that, The energy release device also includes: The second cyclone separator has its steam inlet connected to the steam outlet of the calcium oxide hydration reaction fluidized bed. The steam outlet of the second cyclone separator and the steam outlet of the steam generator are both connected to the steam inlet of the second heat exchanger network.

6. The energy storage system based on thermochemical energy storage and Brayton cycle according to claim 5, characterized in that, The energy release device also includes: A steam mixer, wherein the steam inlet of the steam mixer is connected to the steam outlet of the second cyclone separator and the steam outlet of the steam generator, and the steam outlet of the steam mixer is connected to the steam inlet of the second heat exchanger network.

7. An operation method for an energy storage system based on thermochemical energy storage and Brayton cycle, characterized in that, The operating method is based on the energy storage system based on thermochemical energy storage and Brayton cycle as described in any one of claims 1 to 6, and the operating method includes: The excess power of the power grid is used to drive the first motor to rotate, and the first motor drives the first compressor to work, so as to compress supercritical carbon dioxide to a high temperature and high pressure state. High-temperature and high-pressure supercritical carbon dioxide is introduced into a calcium hydroxide calcination reactor to heat the calcium hydroxide, causing the calcium hydroxide to decompose into calcium oxide solid particles and water vapor. The calcium hydroxide entering the calcium hydroxide calcination reactor is preheated by utilizing the residual heat carried by the calcium oxide solid particles and water vapor through the first heat exchange network.

8. The operation method of the energy storage system based on thermochemical energy storage and Brayton cycle according to claim 7, characterized in that, Also includes: Calcium oxide solid particles are reacted with water vapor in a calcium oxide hydration fluidized bed to produce calcium hydroxide. Room temperature supercritical carbon dioxide is fed into the second compressor for heating and pressurization; The carbon dioxide, after being heated and pressurized by the second compressor, is sequentially fed into the second regenerator and the second heat exchanger network to obtain high-temperature and high-pressure supercritical carbon dioxide. High-temperature and high-pressure supercritical carbon dioxide is input into the second turbine to make the second turbine operate and drive the second generator to generate electricity. Medium-temperature supercritical carbon dioxide is fed into a heat exchanger, and the waste heat from the reaction is used to provide heating or cooling to end users.

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