Calcium oxide-calcium hydroxide thermochemical energy storage and release system and method

Abstract

The invention discloses a calcium oxide-calcium hydroxide thermochemical energy storage and release system and method. The energy storage and release system comprises a calcium oxide bin, a calcium hydroxide bin, an energy storage unit and an energy release unit. The energy storage unit comprises an electromagnetic rotary kiln, and the electromagnetic rotary kiln comprises a reaction channel with a feed port, a discharge port and a steam outlet; the energy release unit comprises hydration reaction equipment, and the hydration reaction equipment comprises a first-stage stirring reactor, a second-stage stirring reactor, a first-stage water spraying device, a second-stage water spraying device, a heat exchanger and a flash tank. In the energy release process, a hierarchical regulation and control water spraying technology is adopted, generation of dust-containing invalid steam can be reduced, the heat exchange efficiency and the material temperature stability can be improved, the first-stage stirring reactor adopts a high rotating speed, the second-stage stirring reactor adopts a low rotating speed, material mixing and moving can be promoted, wall surface hot materials are updated, and the heat exchange efficiency is improved; meanwhile, mechanical energy consumption is reduced, and reaction stability and controllability are guaranteed.

Description

Technical Field

[0001] This invention relates to the field of thermochemical energy storage technology, specifically to a calcium oxide-calcium hydroxide thermochemical energy storage and release system and method. Background Technology

[0002] With the continuous increase in the proportion of renewable energy power generation and the growing demand for stable and efficient thermal energy from industrial processes, the development of large-scale, long-cycle, and low-loss thermal energy storage technologies is crucial. Thermochemical energy storage has attracted widespread attention due to its high theoretical energy density and ability to store thermal energy for extended periods at ambient temperatures. Among numerous thermochemical energy storage material systems, CaO / Ca(OH)2 is considered a highly promising medium- and high-temperature energy storage material due to its significant advantages, including wide availability, low cost, non-toxicity, good reversibility, and suitable reaction temperature.

[0003] Calcium oxide-calcium hydroxide achieves energy storage and release based on the following reaction.

[0004] CaO + H₂O = Ca(OH)₂ + Q In the energy storage stage, electrical energy or other thermal energy above the equilibrium temperature, such as hot flue gas, heats calcium hydroxide, causing it to decompose into calcium oxide and water. The input energy is stored in the calcium oxide in the form of chemical bond energy. In the energy release stage, calcium oxide reacts with water to produce calcium hydroxide and releases heat. The released heat can be used to generate steam, which can then be used to generate electricity, thus releasing energy. For calcium-based energy storage systems, some approaches use liquid water directly as the reaction medium in the energy release stage, as shown in Reference 1.

[0005] Reference 1: Chinese patent document with publication number CN115102203A.

[0006] Reference 1 describes a method for energy storage and release of a combined heat and power (CHP) unit under deep peak-shaving operation, belonging to the field of CHP turbine power generation. It involves setting up a high-density calcium oxide thermal storage device. When the turbine unit performs peak shaving according to grid dispatch requirements, excess power generation steam is fed into the high-density calcium oxide thermal storage device. Calcium hydroxide is placed at the bottom of the device, and the high-temperature steam bakes the calcium hydroxide, converting it into calcium oxide and releasing water. The heat energy from the high-quality steam is converted and stored in the calcium oxide. When the grid's power generation requirements increase, demineralized water is sprayed onto the stored calcium oxide, generating a large amount of steam in the high-density calcium oxide thermal storage device. This steam drives a small turbine unit to generate electricity. Another high-density calcium oxide thermal storage device and a steam-electric boiler are also installed to convert the electricity generated by the CHP unit at minimum steam output into steam.

[0007] The above method directly injects excess water into the calcium oxide medium, and the resulting steam inevitably carries a certain amount of calcium oxide / calcium hydroxide powder. Industrial applications, whether for heating or power generation, have strict requirements regarding the particulate matter content of steam, severely limiting the uses of steam produced by this method.

[0008] Currently, thermochemical energy storage systems based on the calcium oxide-calcium hydroxide system typically employ fluidized bed reactors or fixed bed reactors. For example, in the calcium hydroxide thermochemical energy storage system developed by a team at East China University of Science and Technology, both the decomposition and synthesis reactors are fluidized bed reactors. The calcium hydroxide fluidized bed thermochemical energy storage system developed by Shandong Jianzhu University also uses a fluidized bed reactor and employs steam as both the fluidizing agent and reactant. Fixed-bed energy release reactors, such as Wang's (Proposal of a pilot-scale prototype of an 'electricity-in-steam-out' packed-bed reactor for thermochemical energy storage with Ca(OH)2 / CaO), all use steam as the reaction medium. However, these systems require boilers or other steam generation equipment to produce steam as the reaction medium, increasing the system's complexity and cost. Summary of the Invention

[0009] The purpose of this invention is to solve the above-mentioned technical problems existing in the prior art and to provide a calcium oxide-calcium hydroxide thermochemical energy storage and release system and method.

[0010] To address the shortcomings of the aforementioned technical problems, the present invention adopts the following technical solution: a calcium oxide-calcium hydroxide thermochemical energy storage and release system, comprising a calcium oxide silo, a calcium hydroxide silo, an energy storage unit, and an energy release unit; The energy storage unit includes an electromagnetic rotary kiln, which includes a reaction channel with a feed inlet, a discharge outlet, and a steam outlet. A calcium hydroxide silo is connected to the feed inlet of the electromagnetic rotary kiln via a pipeline, and the discharge outlet of the rotary kiln is connected to the calcium oxide silo via a pipeline, thus forming an energy storage path. The energy release unit includes a hydration reaction device, which includes a primary stirred reactor, a secondary stirred reactor, a primary water spray device, a secondary water spray device, a heat exchanger, and a flash tank. The calcium oxide silo is connected to the inlet of the primary stirred reactor via a pipeline, the outlet of the primary stirred reactor is connected to the inlet of the secondary stirred reactor via a pipeline, the outlet of the secondary stirred reactor is connected to the inlet of the first medium channel of the heat exchanger via a pipeline, and the outlet of the first medium channel of the heat exchanger is connected to the calcium hydroxide silo via a pipeline. Both the first-stage and second-stage stirred reactors have jackets on their sidewalls. The inlet of the second medium channel of the heat exchanger is connected to the water source through a pipeline, and the outlet of the second medium channel of the heat exchanger is connected to the jacket of the second-stage stirred reactor through a pipeline. The jackets of the second-stage and first-stage stirred reactors are interconnected, and the jacket of the first-stage stirred reactor is connected to the flash tank through a pipeline. The primary water spray device and the secondary water spray device are respectively installed at the feed inlet of the primary stirred reactor and the secondary stirred reactor.

[0011] As a further optimization of the calcium oxide-calcium hydroxide thermochemical energy storage and release system of the present invention: the upper region of the cross-section of the primary stirred reactor and the secondary stirred reactor is a rectangular structure, and the lower region is a semi-circular structure. The diameter of the semi-circular structure is equal to the top side length of the rectangular structure, and the bottom chord of the semi-circular structure completely coincides with the top side of the rectangular structure.

[0012] As a further optimization of the calcium oxide-calcium hydroxide thermochemical energy storage and release system of the present invention: the water source is a demineralized water source.

[0013] As a further optimization of the calcium oxide-calcium hydroxide thermochemical energy storage and release system of the present invention: several sets of scraper assemblies are provided on the rotating shaft of the primary and secondary stirred reactors. Each set of scraper assemblies includes three scraper pieces distributed circumferentially along the rotating shaft. Each scraper piece includes a scraper body and a connecting rod. One end of the connecting rod is fixedly connected to the rotating shaft, and the other end of the connecting rod is hinged to the scraper body. The connecting rod and the scraper are also connected by a spring. The distance between the scraper and the inner wall is 1-5mm.

[0014] As a further optimization of the calcium oxide-calcium hydroxide thermochemical energy storage and release system of the present invention: the primary stirred reactor is provided with 3 sets of scraper assemblies, and the secondary stirred reactor is provided with 3-5 sets of scraper assemblies.

[0015] As a further optimization of the calcium oxide-calcium hydroxide thermochemical energy storage and release system of the present invention: the water flow direction in the jacket of the first-stage reactor is the same as the material flow direction, and the water flow direction in the jacket of the second-stage reactor is opposite to the material flow direction.

[0016] As a further optimization of the calcium oxide-calcium hydroxide thermochemical energy storage and release system of the present invention: both the primary water spray device and the secondary water spray device include multiple spiral nozzles, the droplet size sprayed by the primary water spray device is 500-10000 micrometers, and the droplet size sprayed by the secondary water spray device is 100-500 micrometers.

[0017] This invention also provides a method for thermochemical energy storage and release of calcium oxide-calcium hydroxide, comprising: Energy storage stage: Calcium oxide particles are fed into a primary stirred reactor and water is sprayed into it. Stirring causes the calcium oxide particles to mix with water, undergo a hydration reaction, and release heat, while simultaneously propelling the reactants downstream. The material after the first-stage reaction falls into the second-stage reactor, and water is sprayed into it to allow the unreacted calcium oxide in the material to continue to undergo a hydration reaction until it is basically completely converted into high-temperature calcium hydroxide powder at a temperature above 200℃. The high-temperature calcium hydroxide powder is heat-exchanged with demineralized water, and the powder after heat exchange is stored. The pressurized demineralized water, after exchanging heat with the high-temperature powder, flows sequentially through the jackets of the secondary reactor and the primary stirred reactor, where it exchanges heat with the materials inside the reactors and is further heated. The demineralized water, whose temperature has risen to over 150°C after the above heat exchange, is flash-evaporated to generate superheated steam. Energy release phase: The stored calcium hydroxide powder is fed into the decomposition reactor, and heat energy is provided to the decomposition reactor to cause the calcium hydroxide to decompose endothermically, generating solid calcium oxide and high-temperature water vapor. The solid calcium oxide produced by decomposition is returned to the calcium oxide silo for energy storage; The high-temperature steam generated from the decomposition will be used for power generation or heating.

[0018] As a further optimization of the calcium oxide-calcium hydroxide thermochemical energy storage and release method of the present invention: the water spray volume of the first-stage stirred reactor is 0.3-0.8 times the reaction equivalence ratio, and the water spray volume of the second-stage stirred reactor is 0.4-0.9 times the reaction equivalence ratio.

[0019] As a further optimization of the calcium oxide-calcium hydroxide thermochemical energy storage and release method of the present invention: the rotation speed of the primary stirred reactor is 10-25 r / min, and the rotation speed of the secondary stirred reactor is 5-15 r / min.

[0020] The present invention has the following beneficial effects: 1. The present invention employs a graded water spraying technology during the energy release process. The first-stage water spraying volume is 0.3-0.8 times the reaction equivalence ratio, and the second-stage water spraying volume is 0.4-0.9 times the reaction equivalence ratio. This can reduce the generation of dust-containing ineffective steam, improve heat exchange efficiency and material temperature stability, strengthen the contact between water and particle cores, improve raw material conversion rate, and reduce energy consumption and loss. 2. In this invention, the stirring rate is controlled in stages during the energy release process. The first-stage stirring reactor uses a high speed, while the second-stage stirring reactor uses a low speed. Temperature monitoring points are set to dynamically adjust the speed, which can promote material mixing and movement, renew the wall heat material and improve heat exchange efficiency, while reducing mechanical energy consumption and ensuring stable and controllable reaction. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the energy release unit in the thermochemical energy storage and release system of the present invention; Figure 2 This is a schematic diagram of the energy storage unit in the thermochemical energy storage and release system of the present invention; Figure 3 This is a schematic diagram showing the positional relationship of the scraper assembly in the stirred reactor within the energy release unit of this invention; Figure 4 This is a schematic diagram of the scraper component in the energy release unit of the present invention; The markings in the diagram are: 1. Connecting rod; 2. Scraper; 3. Spring; 4. Jacket; 5. Agitator blade. Detailed Implementation

[0022] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0023] <Energy Storage and Release System> As shown in the figure: A calcium oxide-calcium hydroxide thermochemical energy storage and release system includes a calcium oxide silo, a calcium hydroxide silo, an energy storage unit, and an energy release unit.

[0024] The energy storage unit includes an electromagnetic rotary kiln, which includes a reaction channel with a feed inlet, a discharge outlet, and a steam outlet. A calcium hydroxide silo is connected to the feed inlet of the electromagnetic rotary kiln via a pipeline, and the discharge outlet of the rotary kiln is connected to the calcium oxide silo via a pipeline, thus forming an energy storage path.

[0025] The energy release unit includes a hydration reaction device, which includes a primary stirred reactor, a secondary stirred reactor, a primary water spray device, a secondary water spray device, a heat exchanger, and a flash tank.

[0026] The upper part of the cross-section of the primary stirred reactor and the secondary stirred reactor is a rectangular structure, and the lower part is a semi-circular structure. The diameter of the semi-circular structure is equal to the top side length of the rectangular structure, and the bottom chord of the semi-circular structure completely coincides with the top side of the rectangular structure.

[0027] The calcium oxide silo is connected to the inlet of the primary stirred reactor via a pipeline. The outlet of the primary stirred reactor is connected to the inlet of the secondary stirred reactor via a pipeline. The outlet of the secondary stirred reactor is connected to the inlet of the first medium channel of the heat exchanger via a pipeline. The outlet of the first medium channel of the heat exchanger is connected to the calcium hydroxide silo via a pipeline.

[0028] Both the primary and secondary stirred reactors have jackets on their sidewalls. The inlet of the second medium channel of the heat exchanger is connected to the demineralized water source through a pipeline, and the outlet of the second medium channel of the heat exchanger is connected to the jacket of the secondary stirred reactor through a pipeline. The jackets of the secondary and primary stirred reactors are interconnected, and the jacket of the primary stirred reactor is connected to the flash tank through a pipeline.

[0029] The primary water spray device and the secondary water spray device are respectively installed at the feed inlet of the primary stirred reactor and the secondary stirred reactor.

[0030] Due to the characteristics of calcium-based system reactions, calcium hydroxide expands in volume due to decreased density during the formation of calcium oxide, resulting in smaller particle size and generally a powder form. The accumulated calcium hydroxide / calcium oxide powder has very low effective thermal conductivity, reducing the heat exchange efficiency on the jacket side. Therefore, both the primary and secondary stirred reactors are equipped with several sets of scraper assemblies distributed axially along their rotating shafts. Each scraper assembly includes three scraper blades distributed circumferentially along the rotating shaft. Each scraper blade includes a scraper body 2 and a connecting rod 1. One end of the connecting rod 1 is fixedly connected to the rotating shaft, and the other end is hinged to the scraper body 2. The connecting rod 1 and the scraper body 2 are also connected by a spring 3. The distance between the scraper body 2 and the inner wall is 1-5 mm. The presence of these scrapers effectively reduces the thickness of the powder accumulation at the wall surface, promotes the mixing and exchange of heat materials between the particles at the wall surface and the main reaction zone, and improves the heat exchange efficiency on the jacket side.

[0031] The cross-section of the scraper body 2 can be a plane or a surface with a certain curvature. Considering the possible thermal deformation inside the reactor, the scraper body 2 is movably connected to the connecting rod 1, allowing the scraper body 2 to swing within a certain range. On the rotational side, a spring 3 with a certain preload is provided between the connecting rod 1 and the scraper body 2. This spring 3 limits the range of motion of the scraper body 2. When the reactor is jammed due to large particles or powder agglomerates in the material, the scraper body 2 can rotate upward, increasing the gap between the scraper body 2 and the wall, thereby crossing the obstacle, and then returning to its original position.

[0032] The calcium oxide generated after the energy storage stage is stored in a silo. When energy needs to be released, the calcium oxide enters the primary stirred reactor at a certain rate through a feeding mechanism such as a star-shaped feed valve. The primary stirred reactor is a jacketed device. The lower part of the reactor cross-section is semi-circular, and the upper part can be rectangular. The reactor is equipped with shaft-driven stirring blades, and a liquid water spray device is located at the upper part of the reactor near the feeding position. After the calcium oxide enters the primary reactor from the silo at a certain rate, the primary water spray device is activated. The primary water spray device is equipped with multiple nozzles, preferably spiral nozzles, which produce droplets with a particle size of approximately 200-10000 micrometers. The droplets are sprayed downwards to contact the calcium oxide. The stirring blades in the primary reactor promote the mixing of droplets and calcium oxide, thereby causing a reaction and releasing heat. On the other hand, they generate axial thrust, pushing the calcium oxide / calcium hydroxide downstream.

[0033] The secondary reactor is located below the primary reactor. Calcium oxide / calcium hydroxide particles in the primary reactor move downstream under the influence of a stirring shaft, eventually reaching the tail end. A discharge port is located at the tail end of the primary reactor, directly above the feed inlet of the secondary reactor. Under gravity, the particles from the tail end of the primary reactor enter the secondary reactor. The secondary reactor has a similar structure to the primary reactor, also equipped with a jacket, stirring shaft, and scrapers. The calcium oxide / calcium hydroxide particles entering the secondary reactor mix with secondary spray water. Unreacted calcium oxide in the particle mixture continues to react with water, releasing heat. In the secondary reactor, when the particle mixture reaches the tail end, the calcium oxide has been almost entirely converted to calcium hydroxide, and the material temperature is still above 200°C. At this point, the solid powder passes through a heat exchanger, such as a powder heat exchanger or a jacketed screw conveyor, to exchange heat with the demineralized water, reducing the powder temperature to below 100°C. The heat-exchanged powder is then stored in a calcium hydroxide silo as feedstock for the energy storage reactor.

[0034] The above process describes the flow path for calcium oxide / calcium hydroxide. The steam-side process is as follows: Pressurized demineralized water exchanges heat with the tail discharge of the secondary reactor before entering the jacket of the secondary reactor. After exchanging heat with the material inside the secondary reactor, it enters the jacket of the primary reactor. To improve heat exchange efficiency, in the secondary reactor, the flow direction of the demineralized water in the jacket is opposite to the flow direction of the calcium oxide / calcium hydride, while in the primary reactor, it is the same as the flow direction of the powder. After two stages of heat exchange, the temperature of the demineralized water is above 150℃. It then passes through a flash evaporator to generate superheated steam.

[0035] In the two-stage reactors, the material temperature is significantly higher than 100℃, and the injected water inevitably generates a certain amount of dust-laden steam. The two reactors are connected in a closed loop; a small amount of steam generated in the first-stage reaction enters the second-stage reactor along with the material, and is ultimately drawn off from the tail end of the second-stage reactor along with the steam generated there. This steam first undergoes dust removal through a filtration device before being discharged. Alternatively, it can be directly introduced into a water tank, where direct contact with water causes the steam to condense, simultaneously removing calcium oxide / calcium hydroxide dust. The water in the tank can be used as a spray liquid in the first / second-stage reactors, thereby improving water resource utilization efficiency.

[0036] <Energy Storage and Release Methods> Energy storage stage: Calcium oxide particles are fed into a primary stirred reactor, and water is sprayed into it. The stirring process mixes the calcium oxide particles with water, causes a hydration reaction, and releases heat, while simultaneously propelling the reactants downstream.

[0037] The material after the first-stage reaction falls into the second-stage reactor, and water is sprayed into it to allow the unreacted calcium oxide in the material to continue to undergo a hydration reaction until it is basically completely converted into high-temperature calcium hydroxide powder at a temperature above 200℃.

[0038] The high-temperature calcium hydroxide powder is heat-exchanged with demineralized water, and the powder after heat exchange is stored.

[0039] The pressurized demineralized water, after exchanging heat with the high-temperature powder, flows sequentially through the jackets of the secondary reactor and the primary stirred reactor, where it exchanges heat with the materials inside the reactors and is further heated.

[0040] The demineralized water, whose temperature has risen to over 150°C after the above heat exchange, is flash-evaporated to generate superheated steam.

[0041] The water spray volume in the primary stirred reactor is 0.3-0.8 times the reaction equivalence ratio, and the water spray volume in the secondary stirred reactor is 0.4-0.9 times the reaction equivalence ratio. At atmospheric pressure, the equilibrium temperature of reaction formula 1 is approximately 503℃. After water is sprayed in, the material temperature rapidly rises above 100℃. If a large amount of water continues to be sprayed at this point, the water will rapidly vaporize upon contact with the high-temperature particles, generating a large amount of steam. This steam carries a significant amount of dust and cannot be directly utilized. The temperature of the reactants decreases as the liquid water evaporates, reducing the heat exchange efficiency on the jacket side. Therefore, it is necessary to control the water spray volume in the primary reactor; preferably, the water spray volume in the primary reactor should be 0.3-0.8 times the reaction equivalence ratio. At this excess ratio, the heat released from the reaction of calcium oxide with water is mostly used to heat itself, resulting in a high material temperature inside the reactor, while generating a small amount of water vapor. After heat exchange with the jacket, the powder temperature decreases, ensuring it does not fall below 200℃. Liquid water continues to be sprayed into the secondary reactor. The amount of liquid spray water in the secondary reactor also needs to be controlled. It is preferably 0.4-0.9 times the reaction equivalence ratio. Since unreacted calcium oxide is located at the center of the particles after the primary reactor, the contact efficiency between water and calcium oxide decreases, and the reaction rate slows down. Therefore, the droplets of spray water in this stage reactor should be finer, approximately 100-500 micrometers. At the same time, the spray nozzles should be more dispersed.

[0042] The primary stirred reactor operates at a rotation speed of 10-25 r / min, while the secondary stirred reactor operates at 5-15 r / min. Stirring promotes the mixing of calcium oxide particles with water and drives the particles downstream, determining their residence time. Simultaneously, the scrapers on the stirring shaft ensure the renewal of hot material at the jacket wall, improving the jacket's heat exchange efficiency. The primary reactor contains fresh calcium oxide with a high reaction rate with water. Therefore, a relatively high rotation speed can be used to promote heat exchange at the wall. Preferably, the rotation speed is 10-25 r / min. In the secondary reactor, the calcium oxide particles are covered with calcium hydroxide, resulting in a lower reaction rate and heat release rate. Therefore, a relatively lower rotation speed is preferred to reduce mechanical transmission energy consumption, preferably 5-15 r / min. Temperature monitoring points are installed in the middle and rear of the primary reactor, and the rotation speed is adjusted based on the monitored temperature. When the outlet temperature exceeds 200℃, the rotation speed is increased to decrease the outlet temperature. Temperature monitoring points are also set at the outlet of the secondary reactor. When the outlet temperature of the secondary reactor is higher than 150℃, the rotation speed is increased appropriately to improve the heat exchange efficiency on the jacket side.

[0043] Energy release phase: The stored calcium hydroxide powder is fed into the decomposition reactor, and heat energy is provided to the decomposition reactor to cause the calcium hydroxide to decompose endothermically, generating solid calcium oxide and high-temperature water vapor. The solid calcium oxide produced by decomposition is returned to the calcium oxide silo for energy storage; The high-temperature steam generated from the decomposition will be used for power generation or heating.

[0044] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A calcium oxide-calcium hydroxide thermochemical energy storage and release system, characterized in that: It includes a calcium oxide silo, a calcium hydroxide silo, an energy storage unit, and an energy release unit; The energy storage unit includes an electromagnetic rotary kiln, which includes a reaction channel with a feed inlet, a discharge outlet, and a steam outlet. A calcium hydroxide silo is connected to the feed inlet of the electromagnetic rotary kiln via a pipeline, and the discharge outlet of the rotary kiln is connected to the calcium oxide silo via a pipeline, thus forming an energy storage path. The energy release unit includes a hydration reaction device, which includes a primary stirred reactor, a secondary stirred reactor, a primary water spray device, a secondary water spray device, a heat exchanger, and a flash tank. The calcium oxide silo is connected to the inlet of the primary stirred reactor via a pipeline, the outlet of the primary stirred reactor is connected to the inlet of the secondary stirred reactor via a pipeline, the outlet of the secondary stirred reactor is connected to the inlet of the first medium channel of the heat exchanger via a pipeline, and the outlet of the first medium channel of the heat exchanger is connected to the calcium hydroxide silo via a pipeline. Both the first-stage and second-stage stirred reactors have jackets on their sidewalls. The inlet of the second medium channel of the heat exchanger is connected to the water source through a pipeline, and the outlet of the second medium channel of the heat exchanger is connected to the jacket of the second-stage stirred reactor through a pipeline. The jackets of the second-stage and first-stage stirred reactors are interconnected, and the jacket of the first-stage stirred reactor is connected to the flash tank through a pipeline. The primary water spray device and the secondary water spray device are respectively installed at the feed inlet of the primary stirred reactor and the secondary stirred reactor.

2. The calcium oxide-calcium hydroxide thermochemical energy storage and release system as described in claim 1, characterized in that: The upper region of the cross-section of the primary and secondary stirred reactors is a rectangular structure, and the lower region is a semi-circular structure. The diameter of the semi-circular structure is equal to the top side length of the rectangular structure, and the bottom chord of the semi-circular structure completely overlaps with the top side of the rectangular structure.

3. The calcium oxide-calcium hydroxide thermochemical energy storage and release system as described in claim 1, characterized in that: The water source is a demineralized water source.

4. The calcium oxide-calcium hydroxide thermochemical energy storage and release system as described in claim 1, characterized in that: Both the primary and secondary stirred reactors are equipped with several sets of scraper assemblies distributed axially on their rotating shafts. Each set of scraper assemblies includes three scraper components distributed circumferentially along the rotating shaft. Each scraper component includes a scraper body and a connecting rod. One end of the connecting rod is fixedly connected to the rotating shaft, and the other end of the connecting rod is hinged to the scraper body. The connecting rod and the scraper body are also connected by a spring. The distance between the scraper body and the inner wall is 1-5 mm.

5. The calcium oxide-calcium hydroxide thermochemical energy storage and release system as described in claim 4, characterized in that: The primary stirred reactor is equipped with 3 sets of scraper assemblies, and the secondary stirred reactor is equipped with 3-5 sets of scraper assemblies.

6. The calcium oxide-calcium hydroxide thermochemical energy storage and release system as described in claim 1, characterized in that: The water flow direction in the jacket of the primary reactor is the same as the material flow direction, while the water flow direction in the jacket of the secondary reactor is opposite to the material flow direction.

7. The calcium oxide-calcium hydroxide thermochemical energy storage and release system as described in claim 1, characterized in that: Both the primary and secondary water spray devices include multiple spiral nozzles. The droplet size sprayed by the primary water spray device is 500-10000 micrometers, and the droplet size sprayed by the secondary water spray device is 100-500 micrometers.

8. A thermochemical energy storage and release method for calcium oxide-calcium hydroxide, characterized in that, include: Energy storage stage: Calcium oxide particles are fed into a primary stirred reactor and water is sprayed into it. Stirring causes the calcium oxide particles to mix with water, undergo a hydration reaction, and release heat, while simultaneously propelling the reactants downstream. The material after the first-stage reaction falls into the second-stage reactor, and water is sprayed into it to allow the unreacted calcium oxide in the material to continue to undergo a hydration reaction until it is basically completely converted into high-temperature calcium hydroxide powder at a temperature above 200℃. The high-temperature calcium hydroxide powder is heat-exchanged with demineralized water, and the powder after heat exchange is stored. The pressurized demineralized water, after exchanging heat with the high-temperature powder, flows sequentially through the jackets of the secondary reactor and the primary stirred reactor, where it exchanges heat with the materials inside the reactors and is further heated. The demineralized water, whose temperature has risen to over 150°C after the above heat exchange, is flash-evaporated to generate superheated steam. Energy release phase: The stored calcium hydroxide powder is fed into the decomposition reactor, and heat energy is provided to the decomposition reactor to cause the calcium hydroxide to decompose endothermically, generating solid calcium oxide and high-temperature water vapor. The solid calcium oxide produced by decomposition is returned to the calcium oxide silo for energy storage; The high-temperature steam generated from the decomposition will be used for power generation or heating.

9. The calcium oxide-calcium hydroxide thermochemical energy storage and release method as described in claim 8, characterized in that: The water spray volume of the primary stirred reactor is 0.3-0.8 times the reaction equivalence ratio, and the water spray volume of the secondary stirred reactor is 0.4-0.9 times the reaction equivalence ratio.

10. The calcium oxide-calcium hydroxide thermochemical energy storage and release method as described in claim 8, characterized in that: The primary stirred reactor has a rotation speed of 10-25 r / min, and the secondary stirred reactor has a rotation speed of 5-15 r / min.

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