System and method for steam heating calcium hydroxide heat storage peak shaving

Abstract

The application discloses a system and method for steam heating calcium hydroxide heat storage peak shaving, a reactor shell side is used for filling a mixture of calcium oxide and calcium hydroxide, a reactor inlet of the shell side is communicated with an outlet of a desalted water tank and is used for introducing desalted water into the shell side; a first inlet of a reactor tube side is respectively communicated with a boiler main steam pipeline and a steam turbine high-pressure cylinder, and a second inlet of the tube side is communicated with a boiler feed water pipeline. When the calcium hydroxide stores heat, part of the boiler main steam is introduced into the reactor tube side through the first inlet of the tube side from the boiler main steam pipeline, and is introduced into the boiler feed water pipeline through the second inlet of the tube side after heat release; when the calcium oxide releases heat, the desalted water of the boiler feed water pipeline is introduced into the reactor through the second inlet of the tube side, and is introduced into the steam turbine high-pressure cylinder through the first inlet of the tube side after heat absorption. The application utilizes a small-scale calcium hydroxide / calcium oxide heat storage system to assist a thermal power generating unit in peak shaving, the heat storage system realizes rapid load increase and decrease of the unit by extracting and generating steam, and can significantly improve a variable load rate of the unit.

Description

Technical Field

[0001] This invention belongs to the field of thermal power thermal storage and peak shaving technology, specifically to a system and method for steam-heated calcium hydroxide thermal storage and peak shaving. Background Technology

[0002] Thermal energy storage technology can effectively improve the comprehensive utilization level of energy and has important application value in fields such as power grid peak shaving, industrial energy conservation, and waste heat recovery. Thermal energy storage technology is mainly divided into three categories: sensible heat storage, latent heat storage, and thermochemical heat storage. Among them, thermochemical heat storage has significant advantages such as high energy density, high energy quality, and no heat loss during long-term storage. Among the main thermochemical heat storage systems, the calcium hydroxide / calcium oxide system has the characteristics of high energy density, safety and non-toxicity, low price, and simple operation. Its principle is to achieve the interconversion between high-grade thermal energy and chemical energy through the reversible reaction CaO + H₂O → Ca(OH)₂ for heat storage. It is currently a very promising energy storage method among medium- and high-temperature thermochemical energy storage systems.

[0003] Under the dual-carbon goals, with the low-carbon transformation of the power system and the large-scale grid connection of new energy power generation, the traditional thermal power industry needs to carry out in-depth peak-shaving and flexibility transformation to absorb the grid load fluctuations caused by the spatiotemporal discontinuity of new energy. Thermal power unit coupled with thermal storage technology is the main way to achieve flexible transformation of thermal power units. A common technical approach is to embed a certain scale of thermal storage unit between the traditional boiler and turbine, weakening the original rigid "machine-boiler coupling." Especially for thermal power units that supply electricity based on heat demand, adding thermal storage units can better achieve "thermal-electricity decoupling" and realize flexible heating.

[0004] The coupling of thermochemical thermal storage of calcium hydroxide / calcium oxide with peak shaving of thermal power units is currently in the research stage and has not yet been applied on a large scale. The main problems that need to be solved are complex reactor structure, poor mass and heat transfer, difficulty in reaction control, and poor cycle stability of materials. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a system and method for peak shaving using steam-heated calcium hydroxide thermal storage. This system utilizes a small-scale calcium hydroxide / calcium oxide thermal storage system to assist thermal power units in peak shaving. The thermal storage system achieves rapid load increases and decreases for the unit by extracting and generating steam. It has the advantages of simple system, flexible control, high efficiency, and the ability to significantly improve the unit's load change rate.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a steam-heated calcium hydroxide thermal storage and peak-shaving system, comprising a reactor, wherein the shell side of the reactor is used to fill a mixture of calcium oxide and calcium hydroxide, and the reactor inlet on the shell side is connected to the outlet of a demineralized water tank for introducing demineralized water into the shell side; the first inlet on the tube side of the reactor is connected to the main steam pipeline of the boiler and the high-pressure cylinder of the turbine, respectively, and the second inlet on the tube side is connected to the boiler feedwater pipeline. During calcium hydroxide thermal storage, a portion of the main boiler steam is introduced from the main boiler steam pipeline through the first inlet on the tube side into the reactor tube side, and after releasing heat, it is introduced into the boiler feedwater pipeline through the second inlet on the tube side; during calcium oxide thermal release, the demineralized water from the boiler feedwater pipeline is introduced into the reactor through the second inlet on the tube side, and after absorbing heat, it is introduced into the high-pressure cylinder of the turbine through the first inlet on the tube side.

[0007] Furthermore, the reactor outlet on the reactor shell side is connected to the separator inlet to separate calcium oxide or calcium hydroxide carried in the steam. The first outlet of the separator is connected to the inlet of the low-pressure cylinder of the steam turbine, and the second outlet of the separator is connected to the inlet of the bed material storage tank.

[0008] Furthermore, a spray layer and a fixed bed layer are arranged along the height direction in the reactor shell side. The spray layer and the fixed bed layer are arranged horizontally and opposite to each other. The inlet of the spray layer is connected to the reactor inlet on the shell side. The fixed bed layer is filled with bed material. The inlet of the fixed bed layer is connected to the outlet of the bed material storage tank. The pipe-side pipeline passes through the fixed bed layer, and the bed material is distributed outside the pipe-side pipeline.

[0009] Furthermore, the bed material is a mixture of calcium oxide and calcium hydroxide.

[0010] Furthermore, the spray layer includes multiple nozzles for spraying demineralized water from the demineralized water tank into the fixed bed layer, and both the spray layer and the fixed bed layer are provided at least once.

[0011] Furthermore, the tube side adopts a multi-tube bundle structure of coiled tubes. A first header is provided at the first inlet of the tube side, and a second header is provided at the second inlet of the tube side. The first inlet of the coiled tube bundle is connected to the first header, and the second inlet of the coiled tube bundle is connected to the second header. The first header and the second header are used to distribute the material entering the coiled tube bundle and then pass it into each coil of the coiled tube bundle, or to collect the material in each coil of the coiled tube bundle and discharge the collected material from the coiled tube bundle.

[0012] Furthermore, the inlet of the demineralized water tank is connected to the outlet of the condensate pump.

[0013] Furthermore, the material on the reactor shell side flows at low pressure, with the pressure consistent with the inlet steam pressure of the low-pressure cylinder of the steam turbine; the material on the tube side flows at high pressure, with the pressure consistent with the inlet steam pressure of the high-pressure cylinder of the steam turbine.

[0014] The present invention also provides a method for heat storage and peak shaving of the above system. When the unit is running at reduced load, a portion of the main boiler steam is introduced into the high-pressure cylinder of the steam turbine, and another portion enters the tube side of the reactor through the first inlet. The heat of the main boiler steam in the tube side is transferred to the calcium hydroxide in the shell side of the reactor. The calcium hydroxide absorbs heat and decomposes to generate calcium oxide and water vapor, converting electrical energy into chemical energy for storage. The main boiler steam in the tube side is cooled and condensed to obtain demineralized water. The demineralized water is introduced into the boiler feedwater pipeline through the second inlet on the tube side.

[0015] Furthermore, when the unit is operating at increased load, the demineralized water in the demineralized water tank is fed into the reactor shell side through the reactor inlet. The demineralized water reacts with the calcium oxide in the reactor shell side to generate calcium hydroxide and release heat. Demineralized water is drawn from the boiler feedwater pipeline and fed into the reactor tube side through the second inlet. The demineralized water on the tube side absorbs the heat released by the reaction of calcium oxide and generates water vapor. The water vapor is fed into the high-pressure cylinder of the steam turbine through the first inlet on the reactor tube side. The steam turbine drives the generator to generate electricity, converting the chemical energy stored in the calcium oxide into electrical energy.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects:

[0017] This invention provides a steam-heated calcium hydroxide thermal storage and peak-shaving system. The system couples a calcium hydroxide / calcium oxide thermal storage system with a thermal power unit. The decomposition temperature of calcium hydroxide is 550–600℃, while the main steam temperature of the boiler in a thermal power unit is generally 540–560℃. These two temperatures can be well matched, making it particularly suitable for thermal power unit thermal storage and peak-shaving. Therefore, when the thermal power unit reduces its load, this invention utilizes a portion of the boiler's main steam to heat the calcium hydroxide on the reactor shell side, reducing the amount of steam fed into the turbine. The calcium hydroxide absorbs heat and decomposes to generate calcium oxide and water vapor, converting electrical energy into chemical energy and reducing the output of the thermal power unit. When the thermal power unit increases its load, calcium oxide and water react to generate calcium hydroxide, releasing heat to heat the demineralized water on the reactor tube side, producing steam. This steam is fed into the turbine to perform work, converting chemical energy into electrical energy and increasing the output of the thermal power unit. This system can solve the safety and economic problems of deep peak-shaving and rapid load changes in thermal power units.

[0018] Furthermore, compared to traditional electric heating methods, the present invention uses steam heating, which can reduce the heat exchange process caused by [other factors]. This reduces coal consumption and efficiency losses during frequent peak shaving.

[0019] Furthermore, compared with water thermal storage and molten salt thermal storage, the Ca(OH)2 / CaO system has high energy density, no heat loss during long-term storage, and low price. Using the steam generated by the heat release from the chemical reaction of calcium oxide to assist in peak shaving of thermal power units can significantly reduce the scale and investment of thermal storage systems.

[0020] Furthermore, in existing technologies, the dehydration of calcium hydroxide and the hydration of calcium oxide need to be carried out separately in two reactors, and two bed material storage tanks, one for calcium hydroxide and one for calcium oxide, are required. In this invention, a mixture of calcium hydroxide and calcium oxide is used as the bed material to fill a fixed bed layer, arranged in multiple layers inside the reactor. This combines the functions of the calcium hydroxide dehydration reactor and the calcium oxide hydration reactor into one, simultaneously achieving chemical reaction and material storage within the reactor. The thermal storage system requires only one reactor, eliminating the need for separate calcium hydroxide and calcium oxide bed material storage tanks, resulting in a simpler and easier-to-control overall process.

[0021] Furthermore, calcium oxide and calcium hydroxide have problems such as sintering and corrosion during the reaction process, resulting in poor cycle stability of the system. In this invention, the coil clusters are evenly distributed in the fixed bed, making uniform contact with the bed material and conducting steady-state heat transfer, which can improve the uniformity of heat transfer and prevent local overheating and sintering of calcium hydroxide and calcium oxide.

[0022] Furthermore, the water vapor produced by the decomposition of calcium hydroxide is hot and bulky, making it difficult to utilize and store; direct condensation would result in significant heat loss. In this invention, the reactor shell side operates at low pressure, allowing the water vapor from calcium hydroxide decomposition to directly enter the low-pressure cylinder of the turbine to perform work, and then enter the demineralized water tank. No additional compression or storage equipment is needed, and the enthalpy of the water vapor is directly utilized, improving system efficiency. The reactor tube side operates at high pressure, allowing the generated high-pressure steam to directly flow into the high-pressure cylinder of the turbine to perform work, thus improving the system's power generation efficiency.

[0023] Furthermore, in the calcium hydroxide / calcium oxide thermal storage system of this invention, the required materials calcium hydroxide, calcium oxide, and water can all be recycled, reducing material consumption and improving operational economy. Attached Figure Description

[0024] Figure 1 This invention relates to a system for steam-heated calcium hydroxide storage and peak shaving.

[0025] Figure 2 This is a structural diagram of the fixed-bed reactor in the steam-heated calcium hydroxide thermal storage and peak-shaving system of the present invention.

[0026] Figure 3 This is a schematic diagram of the heat storage process in the steam-heated calcium hydroxide heat storage and peak-shaving system of the present invention.

[0027] Figure 4 This is a schematic diagram of the heat release process of the steam-heated calcium hydroxide thermal storage and peak-shaving system of the present invention.

[0028] In the attached diagram: 1. Boiler main steam pipe; 2. Boiler feedwater pipe; 3. Steam turbine high-pressure cylinder; 4. Steam turbine intermediate-pressure cylinder; 5. Steam turbine low-pressure cylinder; 6. Generator; 7. Condenser; 8. Condensate pump; 9. Demineralized water tank; 10. Low-pressure heater; 11. Deaerator; 12. Feedwater pump; 13. High-pressure heater; 14. Bed material storage tank; 15. Separator; 16. Reactor; 17. Reactor inlet; 18. Reactor outlet; 19. Spray layer; 20. Fixed bed layer; 21. Coil cluster; 22. Second header; 23. First header; 24. Bed material. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0030] like Figure 1 As shown, the present invention provides a steam-heated calcium hydroxide thermal storage and peak-shaving system, comprising: a reactor 16, the reactor 16 including a tube side and a shell side, the shell side being filled with a mixture of calcium oxide and calcium hydroxide, the reactor inlet 17 on the shell side being connected to the outlet of the demineralized water tank 9, the reactor outlet 18 on the shell side being connected to the inlet of the separator 15, the first outlet of the separator 15 being connected to the inlet of the low-pressure cylinder 5 of the steam turbine, the second outlet of the separator 15 being connected to the inlet of the bed material storage tank 14, and the outlet of the bed material storage tank 14 being connected to the bed material inlet of the reactor 16;

[0031] The tube side is used to introduce boiler main steam or demineralized water into reactor 16 for heat exchange. The first inlet of the tube side is connected to the boiler main steam pipeline 1 and the turbine high-pressure cylinder 3, respectively. The second inlet of the tube side is connected to the boiler feedwater pipeline 2. During heat storage, part of the boiler main steam is introduced into reactor 16 from boiler main steam pipeline 1 through the first inlet of the tube side. After heat release, the demineralized water is introduced into boiler feedwater pipeline 2 through the second inlet of the tube side. During heat release, the demineralized water from boiler feedwater pipeline 2 is introduced into reactor 16 through the second inlet of the tube side. After heat absorption, the steam is introduced into turbine high-pressure cylinder 3 through the first inlet of the tube side.

[0032] Preferred, such as Figure 2 As shown, reactor 16 is a fixed-bed reactor with a shell-and-tube structure. A spray layer 19 and a fixed bed layer 20 are horizontally arranged along the height direction on the shell side of reactor 16. The spray layer 19 and the fixed bed layer 20 are arranged in a one-to-one correspondence, and at least one layer of each of the spray layer 19 and the fixed bed layer 20 is provided.

[0033] The inlet of the spray layer 19 is connected to the reactor inlet 17 on the shell side, and the spray layer 19 includes multiple nozzles for spraying demineralized water from the demineralized water tank 9 into the fixed bed 20.

[0034] The fixed bed 20 is filled with bed material 24, which is evenly distributed within the fixed bed 20. The outlet of the bed material storage tank 14 is connected to the fixed bed 20. The pipe-side pipeline passes through the fixed bed 20, and the bed material 24 is distributed outside the pipe-side pipeline.

[0035] The bed material 24 is a mixture of calcium oxide and calcium hydroxide.

[0036] The coil cluster 21 adopts a multi-tube bundle structure on the tube side. A first header 23 is set at the first inlet on the tube side, and a second header 22 is set at the second inlet on the tube side. The first inlet of the coil cluster 21 is connected to the first header 23, and the second inlet of the coil cluster 21 is connected to the second header 22. During the heat storage process, part of the boiler main steam enters the coil cluster 21 from the boiler main steam pipeline 1 through the first header 23. After heat release, the condensate is fed into the boiler feedwater pipeline 2 through the second header 22. During heat release, the demineralized water from the boiler feedwater pipeline 2 enters the coil cluster 21 through the second header 22. After heat absorption, the steam is fed into the high-pressure cylinder 3 of the steam turbine through the first header 23.

[0037] The first header 23 and the second header 22 are used to distribute the material entering the coil cluster 21 and then pass it into each coil of the coil cluster 21, or to collect the material in each coil of the coil cluster 21 and discharge the collected material out of the coil cluster 21.

[0038] Preferably, the inlet of the demineralized water tank 9 is connected to the first outlet of the condensate pump 8 of the steam turbine;

[0039] Preferably, the material at reactor inlet 17 and reactor outlet 18 flows at low pressure, with the pressure being consistent with the inlet steam pressure of the low-pressure cylinder 5 of the steam turbine; the material in the coil cluster 21 flows at high pressure, with the pressure being consistent with the inlet steam pressure of the high-pressure cylinder 3 of the steam turbine.

[0040] Preferably, when the reactor 16 stops operating, the mixture of calcium hydroxide and calcium oxide in the bed material storage tank 14 is sent into the fixed bed 20 to replenish the loss of bed material 24.

[0041] Preferably, the demineralized water tank 9 is kept at normal temperature and pressure and is connected to the atmosphere; the bed material storage tank 14 is kept at normal temperature and pressure and is sealed for storage; the separator 15 adopts a cyclone gas-solid separator, with the solid phase discharged from the bottom and the gas phase discharged from the top.

[0042] Preferably, the inlet of condenser 7 is connected to the outlet of the low-pressure cylinder 5 of the steam turbine. The exhaust gas from the low-pressure cylinder 5 enters condenser 7 and is condensed into demineralized water. The outlet of condenser 7 is connected to the inlet of condensate pump 8. The feedwater inlet of low-pressure heater 10 is connected to the second outlet of condensate pump 8. The steam inlet of low-pressure heater 10 is connected to an intermediate stage of the low-pressure cylinder 5 of the steam turbine, drawing steam from the low-pressure cylinder 5 to heat the feedwater. The outlet of low-pressure heater 10 is connected to the first inlet of deaerator 11. The second inlet of deaerator 11 is connected to an intermediate stage of the intermediate-pressure cylinder 4 of the steam turbine, drawing steam from the intermediate-pressure cylinder 4 to enter deaerator 11. The outlet of deaerator 11 is connected to the inlet of feedwater pump 12. The outlet of feedwater pump 12 is connected to the first inlet of high-pressure heater 13. Feedwater pump 12 is used to increase the pressure of boiler feedwater from deaerator 11. The second inlet of the high-pressure heater 13 is connected to an intermediate stage of the high-pressure cylinder 3 of the steam turbine, drawing steam from the high-pressure cylinder 3 to further heat the boiler feedwater. The outlet of the high-pressure heater 13 is connected to the inlet of the boiler feedwater pipe 2, sending the boiler feedwater into the boiler for heating through the boiler feedwater pipe 2.

[0043] The present invention discloses a peak-shaving process for a steam-heated calcium hydroxide thermal storage system, specifically as follows:

[0044] When the unit is operating at reduced load, according to Figure 3 As shown, the main boiler steam from the main boiler steam pipe 1 is divided into two parts. One part enters the high-pressure cylinder 3 of the turbine, and the other part enters the first header 23 of the reactor 16. The main boiler steam in the first header 23 is distributed into multiple coils of the coil cluster 21. The heat of the main boiler steam is transferred through the coil cluster 21 to the bed material 24 on the fixed bed 20. The calcium hydroxide in the bed material 24 absorbs heat and decomposes to generate calcium oxide and water vapor. The chemical equation is Ca(OH)2→CaO+H2O. After the main steam in the coil is cooled and condensed, it becomes demineralized water and flows into the second header 22. Then, it is sent to the boiler feedwater pipe 2 through the second header 22 for boiler heating.

[0045] Calcium oxide in bed material 24 remains in fixed bed 20. Calcium hydroxide decomposes endothermally to generate calcium oxide and water vapor. The water vapor carries some calcium oxide powder through reactor outlet 18 into separator 15. Calcium oxide and water vapor undergo gas-solid separation in separator 15. Calcium oxide enters bed material storage tank 14, and water vapor flows into turbine low-pressure cylinder 5 to perform work.

[0046] As a portion of the boiler's main steam is bypassed and introduced into the calcium hydroxide / calcium oxide thermal storage system, the unit's power generation load will decrease. The calcium hydroxide in bed material 24 decomposes into calcium oxide, converting electrical energy into chemical energy for storage.

[0047] When the unit is operating at increased load, according to Figure 4As shown, the boiler main steam flow rate from the boiler main steam pipe 1 increases, while demineralized water from the demineralized water tank 9 is sent to the spray layer 19 through the reactor inlet 17. Multiple nozzles in the spray layer 19 spray the demineralized water into the fixed bed layer 20. The demineralized water reacts with the calcium oxide powder in the bed material 24 to generate calcium hydroxide and release heat; the reaction equation is CaO + H₂O → Ca(OH)₂. A portion of the demineralized water is drawn from the boiler feedwater pipe 2 and sent to the second header 22 of the reactor 16, and then distributed into multiple coils of the coil cluster 21. The heat released by the reaction between the calcium oxide powder and the demineralized water is transferred to the demineralized water in the coils through the coil cluster 21. The demineralized water absorbs the heat and generates steam. The steam merges with the boiler main steam in the boiler main steam pipe 1 and flows into the high-pressure cylinder 3 of the turbine to perform work, rotating the turbine and driving the generator 6 to generate electricity.

[0048] A small amount of water vapor generated in reactor 16 carries calcium hydroxide powder through reactor outlet 18 into separator 15. Calcium hydroxide and water vapor undergo gas-solid separation in separator 15. Calcium hydroxide enters bed material storage tank 14, while water vapor is directly vented. The water vapor generated by the calcium hydroxide / calcium oxide thermal storage system flows into the high-pressure cylinder of the steam turbine, increasing the steam intake and thus increasing power generation, converting the chemical energy stored in calcium oxide into electrical energy.

Claims

1. A system for steam-heated calcium hydroxide storage and peak shaving, characterized in that, The reactor (16) includes a shell side for filling a mixture of calcium oxide and calcium hydroxide. The reactor inlet (17) on the shell side is connected to the outlet of the demineralized water tank (9) for introducing demineralized water into the shell side. The first inlet on the tube side of the reactor (16) is connected to the main steam pipe (1) of the boiler and the high-pressure cylinder (3) of the turbine, respectively. The second inlet on the tube side is connected to the boiler feedwater pipe (2). When calcium hydroxide is stored for heat, part of the main steam of the boiler is introduced into the tube side of the reactor (16) through the first inlet on the tube side from the main steam pipe (1). After releasing heat, it is introduced into the boiler feedwater pipe (2) through the second inlet on the tube side. When calcium oxide releases heat, the demineralized water from the boiler feedwater pipe (2) is introduced into the reactor (16) through the second inlet on the tube side. After absorbing heat, it is introduced into the high-pressure cylinder (3) of the turbine through the first inlet on the tube side. A spray layer (19) and a fixed bed layer (20) are arranged along the height direction in the shell side of the reactor (16). The spray layer (19) and the fixed bed layer (20) are arranged horizontally facing each other. The inlet of the spray layer (19) is connected to the reactor inlet (17) on the shell side. The fixed bed layer (20) is filled with bed material (24). The inlet of the fixed bed layer (20) is connected to the outlet of the bed material storage tank (14). The pipe side pipeline passes through the fixed bed layer (20). The bed material (24) is distributed outside the pipe side pipeline. The spray layer (19) includes multiple nozzles for spraying demineralized water from the demineralized water tank (9) into the fixed bed layer (20). Both the spray layer (19) and the fixed bed layer (20) are provided with at least one layer.

2. The system for steam-heated calcium hydroxide storage and peak shaving according to claim 1, characterized in that, The reactor outlet (18) on the shell side of the reactor (16) is connected to the inlet of the separator (15) to separate calcium oxide or calcium hydroxide carried in the steam. The first outlet of the separator (15) is connected to the inlet of the low-pressure cylinder (5) of the steam turbine, and the second outlet of the separator (15) is connected to the inlet of the bed material storage tank (14).

3. The system for steam-heated calcium hydroxide storage and peak shaving according to claim 1, characterized in that, The bed material (24) is a mixture of calcium oxide and calcium hydroxide.

4. The system for steam-heated calcium hydroxide storage and peak shaving according to claim 1, characterized in that, The coil cluster (21) with a multi-tube bundle structure is provided on the tube side. A first header (23) is provided at the first inlet of the tube side, and a second header (22) is provided at the second inlet of the tube side. The first inlet of the coil cluster (21) is connected to the first header (23), and the second inlet of the coil cluster (21) is connected to the second header (22). The first header (23) and the second header (22) are used to distribute the material entering the coil cluster (21) and then pass it into each coil of the coil cluster (21), or to collect the material in each coil of the coil cluster (21) and discharge the collected material out of the coil cluster (21).

5. The system for steam-heated calcium hydroxide storage and peak shaving according to claim 1, characterized in that, The inlet of the demineralized water tank (9) is connected to the outlet of the condensate pump (8).

6. The system for steam-heated calcium hydroxide storage and peak shaving according to claim 1, characterized in that, The material on the shell side of reactor (16) flows at low pressure, and the pressure is consistent with the inlet steam pressure of the low-pressure cylinder (5) of the steam turbine; the material on the tube side flows at high pressure, and the pressure is consistent with the inlet steam pressure of the high-pressure cylinder (3) of the steam turbine.

7. The thermal storage and peak-shaving method of the system according to any one of claims 1 to 6, characterized in that, When the unit is running at reduced load, a portion of the main boiler steam is fed into the high-pressure cylinder (3) of the turbine, and another portion enters the tube side of the reactor (16) through the first inlet. The heat of the main boiler steam in the tube side is transferred to the calcium hydroxide in the shell side of the reactor (16). The calcium hydroxide absorbs heat and decomposes to generate calcium oxide and water vapor, converting electrical energy into chemical energy for storage. The main boiler steam in the tube side is cooled and condensed to obtain demineralized water. The demineralized water is fed into the boiler feedwater pipeline (2) through the second inlet on the tube side.

8. The thermal storage and peak-shaving method of the system according to any one of claims 1 to 6, characterized in that, When the unit is running at increased load, the demineralized water in the demineralized water tank (9) is sent to the shell side of the reactor (16) through the reactor inlet (17). The demineralized water reacts with the calcium oxide in the shell side of the reactor (16) to generate calcium hydroxide and release heat. The demineralized water is drawn from the boiler feed water pipe (2) and sent to the tube side of the reactor (16) through the second inlet. The demineralized water on the tube side absorbs the heat released by the reaction of calcium oxide and generates water vapor. The water vapor is passed into the high-pressure cylinder (3) of the steam turbine through the first inlet on the tube side of the reactor (16). The steam turbine drives the generator (6) to generate electricity, converting the chemical energy stored in the calcium oxide into electrical energy.

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