Solar thermal power generation system based on solid particle heat storage and release

Abstract

The invention relates to the technical field of solid particle heat storage, and discloses a solar thermal power generation system based on solid particle heat storage and release, which comprises an absorption tower assembly, a solid particle-carbon dioxide heat exchange device, a power generation device, a belt and a conveying device, the heliostat field reflects a solar beam to the heat absorber; the solid particle-carbon dioxide heat exchange device comprises a gas buffer layer, a carbon dioxide working medium pipeline, fins, a low-temperature high-pressure carbon dioxide working medium inlet, a high-temperature high-pressure carbon dioxide working medium outlet, a solid particle buffer screening layer, a solid particle channel, a solid particle hot tank, a solid particle cold tank and a low-pressure high-temperature carbon dioxide outlet. Solid particles are used as a heat storage medium. And meanwhile, the problems of corrosion, leakage, preheating, salt blockage and the like in the fused salt heat storage system are effectively solved, the safety and reliability of the system are improved, and the system cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of solid particle thermal energy storage technology, and in particular to a solar thermal power generation system based on solid particle thermal energy storage and release. Background Technology

[0002] With the ever-increasing global demand for clean energy, solar energy, as an inexhaustible energy source, has received widespread attention for its development and utilization. Among numerous solar energy utilization technologies, concentrated solar power generation technology, with its high energy conversion efficiency and large-scale application potential, is gradually becoming one of the important directions for future energy development. By focusing sunlight through concentrating devices, concentrated solar power generation technology can achieve the effective capture and utilization of solar energy, providing new ideas and approaches for solving global energy problems.

[0003] In centralized solar power generation technologies, supercritical carbon dioxide (S-CO2) is used as a working fluid to drive turbine power generation, exhibiting high thermal efficiency, compact system structure, and strong energy storage capacity. These advantages make it highly promising for improving system performance and economic efficiency. Meanwhile, molten salt, as a highly efficient heat transfer and storage medium, is widely used in solar thermal power generation systems. However, molten salt has some limitations: its corrosiveness and leakage risk increase system maintenance costs and complexity; its high melting point makes it prone to blockage at low temperatures, requiring additional electric heaters for operation, further increasing system complexity; in addition, the operating temperature of molten salt is limited, and thermal decomposition at high temperatures may occur, limiting the maximum operating temperature of the system.

[0004] As an alternative to molten salt thermal energy storage, solid particle thermal energy storage technology is of significant development importance due to its advantages such as high safety, simple structure, good economy, and high operating temperature. Flow-type solid particle thermal energy storage technology can improve the heat exchange efficiency of the system and enhance its circulation performance and flexibility. However, solid particles have a large mass, making them prone to accumulation, and causing more severe wear on the heat exchange device during high-speed flow. Furthermore, existing solid particle thermal energy storage technologies often employ a method of first storing solid particles in a heat tank and then releasing heat. This not only wastes space in the lower half of the tower, increasing the system's footprint, but also further increases the system's complexity by requiring additional equipment to assist in the entry of solid particles into the heat exchanger.

[0005] Therefore, developing a solar thermal power generation system suitable for solid particle thermal storage has significant practical implications. Based on the current research background, this study proposes a flexible, integrated solar thermal power generation system based on solid particle thermal storage and release. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a solar thermal power generation system based on the storage and release of heat by solid particles.

[0007] This invention is achieved through the following technical solution:

[0008] A solar thermal power generation system based on solid particle heat storage and release includes an absorption tower assembly, a solid particle-carbon dioxide heat exchange device, a power generation device, a belt, and a conveyor.

[0009] The absorption tower assembly consists of a heliostat field and a heat absorber. The heliostat field reflects the solar beams to the heat absorber, which absorbs the heat from the solar beams to provide a heat source for the system.

[0010] The solid particle-carbon dioxide heat exchange device includes a gas buffer layer, carbon dioxide working fluid pipelines, fins, a low-temperature, high-pressure carbon dioxide working fluid inlet, a high-temperature, high-pressure carbon dioxide working fluid outlet, a solid particle buffer sieve layer, a solid particle channel, a solid particle hot tank, a solid particle cold tank, and a low-pressure, high-temperature carbon dioxide outlet. Its function is to achieve heat exchange between solid particles and high-pressure carbon dioxide working fluid.

[0011] The power generation device includes a compressor, a turbine, a generator, a heat exchanger, and a cooler. Heated, high-temperature, high-pressure carbon dioxide working fluid enters the turbine, driving its rotation and powering the generator. After power generation, the carbon dioxide working fluid is cooled by the heat exchanger, then compressed by the compressor and returned to the solid particle-carbon dioxide heat exchanger, forming a closed loop and completing the power generation process.

[0012] The belt is used to transport solid particles, and the conveyor is used to convey the solid particles upward.

[0013] Preferably, the heliostat can be adjusted according to the angle of sunlight to maximize the intensity of sunlight reflected to the absorber. Solid particles are transported to the absorber by the fourth belt to absorb heat. The absorber is coaxially arranged with the center of the carbon dioxide working fluid pipeline. The gas buffer layer consists of multiple layers, arranged above each layer of the carbon dioxide working fluid pipeline, to reduce particle velocity, prevent excessive particle flow velocity from impacting the heat exchange pipeline, and ensure uniform distribution of downstream particles, preventing particle accumulation and thus promoting more efficient heat exchange. The upper part of the gas buffer layer is arched, and the lower part is a rectangular hollow structure with multiple circular holes on the sides. High-pressure carbon dioxide is horizontally ejected from these holes, forming the gas buffer layer. The carbon dioxide flowing in the solid particle channel not only acts as a gas buffer to slow down the solid particles but also further exchanges heat with them, ultimately becoming low-pressure, high-temperature carbon dioxide, which flows out from the low-pressure carbon dioxide outlet. The low-pressure, high-temperature carbon dioxide outlet is connected to the solid particle channel.

[0014] Preferably, the carbon dioxide working fluid pipeline consists of a multi-layer structure, with each layer of pipelines arranged vertically and longitudinal fins welded to the outside. The gaps between the fins and the pipeline allow for the flow of solid particles, which exchange heat with the carbon dioxide working fluid inside the pipeline. The longitudinal fins are equidistant along the circumference of the pipeline, with a uniform height, but their cross-sectional length varies depending on the gaps between the pipelines; fins with larger gaps are longer to facilitate effective heat exchange for the solid particles. The outlet of the next layer of pipeline is connected to the inlet of the previous layer via a longitudinal U-shaped pipe.

[0015] Preferably, the solid particle buffer screen layer consists of at least two screen layers, and its tilt angle can be adjusted according to operating conditions to convey solid particles to the first or second conveyor belt. Two symmetrical solid particle channels are provided above the screen layer to facilitate the entry of solid particles into the conveyor belt. During the day when sunlight is strong, the solid particles are at a high temperature, and the solid particles after heat exchange with carbon dioxide still have temperature recovery value. At this time, the screen mesh is open, and the solid particles pass through the screen into the solid particle heat tank for storage, to be used for power generation at night. During the day when sunlight is weak, the solid particles are at a low temperature, and the temperature recovery value of the solid particles after heat exchange is low. By rotating the bottom screen, the screen mesh is closed. During the day, the solid particle buffer screen layer tilts towards the first conveyor belt, and some or all of the solid particles enter the first conveyor belt through the solid particle channels; at night, the solid particle buffer screen layer tilts towards the second conveyor belt, and all solid particles enter the second conveyor belt through the solid particle channels, at which time the screen mesh is not open.

[0016] Preferably, the hot tank is used to store high-temperature solid particles during the day, and its bottom remains closed during the day. At night, the bottom of the hot tank is opened, and the high-temperature solid particles are conveyed to the first conveyor via a third belt, and then conveyed to the solid particle inlet by the combined action of the second conveyor. At this time, since there is no sun, the heat absorber does not work, but the high-temperature solid particles continue to exchange heat with the carbon dioxide working fluid. The flow rate of the high-pressure carbon dioxide working fluid is lower at this time than during the day, partly because the heat mass of the solid particles is lower, and partly because electricity demand is lower during off-peak hours at night. The flow rate of both the high-pressure carbon dioxide working fluid and the flow rate of the solid particles are determined by the required power generation. After heat exchange, the solid particles enter the cold tank, where the solid particle buffer screen is inclined towards the cold tank, and the solid particles are conveyed to the solid particle cold tank via a second belt, at which time the bottom of the cold tank is closed. During the day, the bottom of the cold tank is opened, and the solid particles are conveyed to the solid particle inlet for further heating via the third belt and the conveyor.

[0017] Preferably, the cooler is used to cool the carbon dioxide working fluid, and the compressor is used to pressurize the low-temperature carbon dioxide. The pressurized carbon dioxide working fluid is divided into two streams: one flows into a heat exchanger to heat the pressurized carbon dioxide initially; the other enters a gas buffer layer. The pressurized and heated carbon dioxide working fluid, after passing through the compressor, heat exchanger, and solid particle-carbon dioxide heat exchanger, is used to drive a turbine, which in turn drives a generator to produce electricity. The low-pressure, high-temperature carbon dioxide released from the low-pressure carbon dioxide outlet merges with the low-pressure carbon dioxide from the turbine, serving as a heat source for the heat exchanger to heat the high-pressure, low-temperature carbon dioxide.

[0018] Preferably, the system includes a first belt, a second belt, a third belt, and a fourth belt, as well as a first conveying device and a second conveying device. The first belt is connected to the second conveying device, and the third belt is connected to the first conveying device. The first and second conveying devices are arranged coaxially. The second conveying device conveys solid particles upwards to the fourth belt, which then conveys the solid particles to the solid particle inlet. The first belt is used to convey the heat-exchanged solid particles to the second conveying device; the fourth belt is used to further convey the solid particles conveyed by the second conveying device to the solid particle inlet; the second belt is used to convey low-temperature solid particles to the cold tank; the third belt is used to convey low-temperature solid particles to the first conveying device during the day and high-temperature solid particles to the first conveying device at night.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. Using solid particles as the heat storage medium makes it suitable for high-temperature operating environments, enabling the temperature of the heat exchange medium to be raised to higher levels, thereby improving the overall system efficiency. Simultaneously, it effectively solves problems such as corrosion, leakage, preheating, and salt blockage existing in molten salt heat storage systems, improving system safety and reliability while reducing system costs.

[0021] 2. By designing the heat exchange pipes, direct contact between the heat exchange medium and solid particles is avoided, thereby reducing the pressure loss of the heat exchange medium and ensuring that it can efficiently absorb the heat from the solid particles.

[0022] 3. A multi-layer gas buffer structure was designed, which can effectively reduce the flow rate of solid particles, alleviate the scouring damage of solid particles to the equipment, make the solid particles more uniformly distributed, avoid the occurrence of particle accumulation, promote effective heat exchange between solid particles and heat exchange medium, and improve the stability and heat exchange efficiency of the system.

[0023] 4. This invention designs an integrated system that can fully utilize solar energy for heat collection and storage during the day, and flexibly adjust the power generation according to actual electricity demand, thereby achieving flexible power generation and improving the system's adaptability and economy.

[0024] 5. By recovering heat from the gas buffer layer, the system's energy utilization efficiency is further improved, achieving efficient energy recycling and enhancing the overall performance of the system. Attached Figure Description

[0025] Figure 1 This is a diagram of a solar thermal power generation system based on the storage and release of heat from solid particles.

[0026] Figure 2 It is an isometric drawing of the carbon dioxide working fluid pipeline and the gas buffer layer.

[0027] Figure 3 This is a diagram showing the distribution of fins in a carbon dioxide working fluid pipeline.

[0028] Figure 4 This is a schematic diagram of a solid particle buffer sieve.

[0029] Labeling Explanation: 1: Heliostat field; 2: Absorber; 3: Gas buffer layer; 3-1: Gas buffer layer circular hole; 4: Carbon dioxide working fluid pipe; 5: Fin; 6: Low temperature and high pressure carbon dioxide working fluid inlet; 7: High temperature and high pressure carbon dioxide working fluid outlet; 8: Solid particle inlet; 9: Solid particle outlet; 10: Solid particle buffer sieve layer; 10-1: Sieves layer channel; 10-2: Screen; 11: First belt; 12: Second belt; 13: Third belt; 14: First conveyor; 15: Second conveyor; 16: Fourth belt; 17: Solid particle hot tank; 18: Solid particle cold tank; 19: Compressor; 20: Turbine; 21: Generator; 22: Cold-heat exchanger; 23: Cooler; 24: Low pressure and high temperature carbon dioxide outlet; 25: Solid particle channel. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Please see Figure 1-4 The present invention provides a technical solution:

[0032] A solar thermal power generation system based on solid particle heat storage and release includes an absorption tower assembly, a solid particle-carbon dioxide heat exchange device, a power generation device, a belt, and a conveyor.

[0033] The absorption tower assembly consists of a heliostat field 1 and a heat absorber 2. The heliostat field 1 reflects the solar beams to the heat absorber 2, and the heat absorber 2 absorbs the heat from the solar beams to provide a heat source for the system.

[0034] The solid particle-carbon dioxide heat exchange device includes a gas buffer layer 3, a carbon dioxide working fluid pipeline 4, fins 5, a low-temperature and high-pressure carbon dioxide working fluid inlet 6, a high-temperature and high-pressure carbon dioxide working fluid outlet 7, a solid particle buffer screen layer 10, a solid particle channel 25, a solid particle hot tank 17, a solid particle cold tank 18, and a low-pressure and high-temperature carbon dioxide outlet 24.

[0035] The power generation device includes a compressor 19, a turbine 20, a generator 21, a heat exchanger 22, and a cooler 23.

[0036] The belts include a first belt 11, a second belt 12, a third belt 13, and a fourth belt 16 for conveying solid particles. The conveying device includes a first conveying device 14 and a second conveying device 15 for conveying the solid particles upward.

[0037] The heliostat field 1 can be adjusted according to the angle of sunlight to maximize the intensity of sunlight reflected to the absorber. Solid particles are transported to the absorber 2 by the fourth belt 16 to absorb heat. The absorber 2 is coaxially arranged with the carbon dioxide working fluid pipe 4. The gas buffer layer 3, composed of multiple layers, is arranged above each layer of the carbon dioxide working fluid pipe 4 to reduce particle velocity, prevent excessive particle flow velocity from impacting the heat exchange pipes, and ensure uniform distribution of downstream particles, preventing particle accumulation and promoting more efficient heat exchange. The upper part of the gas buffer layer 3 is arched, and the lower part is a rectangular hollow structure with multiple circular holes on the sides. High-pressure carbon dioxide is horizontally ejected from these holes, forming the gas buffer layer. The carbon dioxide flowing in the solid particle channel 25 not only acts as a gas buffer to slow down the solid particles but also further exchanges heat with them, ultimately becoming low-pressure, high-temperature carbon dioxide, which flows out from the low-pressure, high-temperature carbon dioxide outlet 24, which is connected to the solid particle channel 25.

[0038] The carbon dioxide working medium pipeline 4 is composed of a multi-layer structure, with each layer of pipeline arranged vertically. Fins 5 are welded to the outside of the carbon dioxide working medium pipeline 4. The gap between the fins 5 and the carbon dioxide working medium pipeline 4 is used for the flow of solid particles. The solid particles exchange heat with the carbon dioxide working medium inside the carbon dioxide working medium pipeline 4. The fins 5 are arranged equidistantly along the circumference of the carbon dioxide working medium pipeline 4. The outlet of the next layer of carbon dioxide working medium pipeline 4 is connected to the inlet of the previous layer of carbon dioxide working medium pipeline 4 through a longitudinal U-shaped pipeline.

[0039] The solid particle buffer screen layer 10 consists of at least two layers of screens and the tilt angle can be adjusted according to the working conditions so as to convey solid particles to the first belt 11 or the second belt 12. Two symmetrical solid particle channels 25 are provided above the solid particle buffer screen layer 10 to facilitate the entry of solid particles into the belt.

[0040] The solid particle hot tank 17 is used to store high-temperature solid particles during the day, and its bottom is kept closed during the day.

[0041] The cooler 23 is used to cool the carbon dioxide working fluid, and the compressor 19 is used to pressurize the low-temperature carbon dioxide. The carbon dioxide working fluid after being pressurized by the compressor 19 is divided into two streams: one stream flows into the cold-heat exchanger 22 to heat the pressurized carbon dioxide once; the other stream enters the gas buffer layer 3. The carbon dioxide working fluid after being pressurized and heated by the compressor 19, the cold-heat exchanger 22 and the solid particle-carbon dioxide heat exchange device is used to drive the turbine 20 and drive the generator 21 to generate electricity.

[0042] The solar thermal power generation system based on solid particle heat storage and release includes a first belt 11, a second belt 12, a third belt 13, and a fourth belt 16, as well as a first conveyor device 14 and a second conveyor device 15. The first belt 11 is connected to the second conveyor device 15, and the third belt 13 is connected to the first conveyor device 14. The first conveyor device 14 and the second conveyor device 15 are coaxially arranged. The second conveyor device 15 conveys the solid particles upward to the fourth belt 16, and the fourth belt 16 then conveys the solid particles to the solid particle inlet 8. The first belt 11 is used to convey the heat-exchanged solid particles to the second conveyor device 15; the fourth belt 16 is used to further convey the solid particles conveyed by the second conveyor device 15 to the solid particle inlet 8; the second belt 12 is used to convey low-temperature solid particles to the cold tank; the third belt 13 is used to convey low-temperature solid particles to the first conveyor device 14 during the day and to convey high-temperature solid particles to the first conveyor device 14 at night.

[0043] Operating Procedures: During the day, the heliostat field 1 is adjusted according to the angle of sunlight to ensure that the intensity of the sunlight reflected to the absorber is maximized. Solid particles are transported to the absorber 2 by the fourth belt 16 to absorb heat. Subsequently, the solid particles pass through the first gas buffer layer 3. Low-temperature, high-pressure carbon dioxide is horizontally ejected from the circular holes of the buffer layer, forming a gas buffer layer. This layer reduces the velocity of the solid particles, prevents excessive particle velocity from impacting the heat exchange pipes, ensures uniform particle distribution, prevents particle accumulation, and promotes more efficient heat exchange.

[0044] Solid particles exchange heat with the high-pressure carbon dioxide working medium in the carbon dioxide working medium pipe 4 within the solid particle channel 25, transferring heat to the working medium. Ultimately, the carbon dioxide in the pipe becomes high-pressure, high-temperature carbon dioxide and flows out from the working medium outlet. Within the solid particle channel 25, the high-pressure, low-temperature carbon dioxide, acting as a gas buffer layer, not only reduces the velocity of the solid particles but also exchanges heat with them. Subsequently, due to the density difference, the carbon dioxide moves upward, eventually transforming into low-pressure, high-temperature carbon dioxide, which is then discharged from the low-pressure carbon dioxide outlet.

[0045] After heat exchange, the solid particles flow out from the solid particle outlet 9 and pass through the solid particle buffer screen 10. During strong sunlight, the solid particles are at a high temperature and still retain heat recovery value after heat exchange with carbon dioxide. At this time, the mesh openings of the solid particle buffer screen are connected, and the solid particles pass through the screen into the solid particle heating tank for storage, to be used for power generation at night. During this time, some solid particles are recycled via the first belt 11 and the second conveyor 15, while the rest are stored. When the light intensity is weak, rotating the bottom screen 10-2 closes the gaps between the screens, allowing all solid particles to be conveyed via the first belt 11 to the second conveyor 15. During the day, the bottom of the heating tank is closed, and the bottom of the cooling tank is open. Under the action of the third belt 13 and the first and second conveyors 14 and 15, the low-temperature solid particles are conveyed to the solid particle inlet for further heating.

[0046] At night, due to the absence of sunlight, the high-temperature solid particles in the hot tank begin to function. The bottom of the hot tank opens, and the high-temperature solid particles are conveyed to the first conveyor device 14 via the third belt 13. With the combined action of the second conveyor device 15, the high-temperature solid particles are conveyed to the solid particle inlet 8. At this time, the absorber 2 is not operating, but the high-temperature solid particles continue to exchange heat with the carbon dioxide working fluid. Meanwhile, the mesh openings of the solid particle buffer screen are not interconnected, and the solid particle buffer screen tilts towards the second belt 12. The solid particles, after exchanging heat with the carbon dioxide, enter the cold tank, at which point the bottom of the cold tank closes.

[0047] The high-pressure, high-temperature carbon dioxide working fluid, heated by the solid particles, enters the turbine, driving its rotation and thus powering generator 21 to generate electricity. The generated carbon dioxide working fluid merges with the high-temperature, low-pressure carbon dioxide exiting the gas buffer layer and enters the channel of the heat exchanger 22, where it is heated by the low-temperature, high-pressure carbon dioxide, transforming itself into a low-temperature, low-pressure carbon dioxide working fluid. Subsequently, this low-temperature, low-pressure carbon dioxide working fluid enters the cooler 23 for further cooling, and is then pressurized by the compressor 19 and divided into two streams: one part acts as a gas buffer layer, reducing the velocity of the solid particles and promoting heat exchange; the other part flows into the heat exchanger for primary heating, then returns to the solid particle-carbon dioxide heat exchanger for secondary heating, completing the entire cycle.

[0048] Through the above steps, the solar thermal power generation system of the present invention achieves effective collection and conversion of solar energy, efficient heat storage and release of solid particles, and recycling of carbon dioxide working fluid, ensuring stable operation of the system during both day and night, and improving the overall efficiency and economy of the system.

[0049] This specific embodiment is merely an explanation of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A solar thermal power generation system based on solid particle heat storage and release, comprising an absorption tower assembly, a solid particle-carbon dioxide heat exchange device, a power generation device, a belt conveyor, and a transmission device, characterized in that: The absorption tower assembly consists of a heliostat field (1) and a heat absorber (2). The heliostat field (1) reflects the solar beam to the heat absorber (2), and the heat absorber (2) absorbs the heat of the solar beam to provide a heat source for the system. The solid particle-carbon dioxide heat exchange device includes a gas buffer layer (3), a carbon dioxide working medium pipeline (4), fins (5), a low-temperature and high-pressure carbon dioxide working medium inlet (6), a high-temperature and high-pressure carbon dioxide working medium outlet (7), a solid particle buffer screen layer (10), a solid particle channel (25), a solid particle hot tank (17), a solid particle cold tank (18), and a low-pressure and high-temperature carbon dioxide outlet (24). The power generation device includes a compressor (19), a turbine (20), a generator (21), a heat exchanger (22), and a cooler (23). The belts include a first belt (11), a second belt (12), a third belt (13), and a fourth belt (16) for conveying solid particles. The conveying device includes a first conveying device (14) and a second conveying device (15) for conveying the solid particles upward.

2. The solar thermal power generation system based on solid particle heat storage and release according to claim 1, characterized in that: The heliostat field (1) can be adjusted according to the angle of sunlight so that the intensity of sunlight reflected to the heat absorber is maximized. The solid particles are transported to the heat absorber (2) to absorb heat under the transmission action of the fourth belt (16). The heat absorber (2) and the carbon dioxide working fluid pipe (4) are arranged coaxially. The gas buffer layer (3) consists of multiple layers and is arranged above each layer of carbon dioxide working fluid pipe (4) to reduce the particle velocity, prevent the particle flow velocity from being too high and causing impact on the heat exchange pipe, and make the downstream particles evenly distributed to prevent particle accumulation, thereby promoting more sufficient particle heat exchange. The upper part of the gas buffer layer (3) is arranged in an arch shape, and the lower part is a rectangular hollow structure. The side of the rectangular block is provided with multiple round holes. High-pressure carbon dioxide is sprayed horizontally from the round holes to form a gas buffer layer. The carbon dioxide flowing in the solid particle channel (25) not only acts as a gas buffer to slow down the solid particles, but also exchanges heat with the solid particles, eventually becoming low-pressure high-temperature carbon dioxide, which flows out from the low-pressure high-temperature carbon dioxide outlet (24), which is connected to the solid particle channel (25).

3. A solar thermal power generation system based on solid particle heat storage and release according to claim 1, characterized in that: The carbon dioxide working medium pipeline (4) is composed of a multi-layer structure, with each layer of pipeline arranged vertically. Fins (5) are welded to the outside of the carbon dioxide working medium pipeline (4). The gap between the fins (5) and the carbon dioxide working medium pipeline (4) is used for the flow of solid particles. The solid particles exchange heat with the carbon dioxide working medium in the carbon dioxide working medium pipeline (4). The fins (5) are arranged equidistantly along the circumference of the carbon dioxide working medium pipeline (4). The outlet of the next layer of carbon dioxide working medium pipeline (4) is connected to the inlet of the previous layer of carbon dioxide working medium pipeline (4) through a longitudinal U-shaped pipeline.

4. A solar thermal power generation system based on solid particle heat storage and release according to claim 1, characterized in that: The solid particle buffer screen layer (10) consists of at least two layers of screens and the tilt angle can be adjusted according to the working conditions so as to convey solid particles to the first belt (11) or the second belt (12). Two symmetrical solid particle channels (25) are provided above the solid particle buffer screen layer (10) to facilitate the entry of solid particles into the belt.

5. A solar thermal power generation system based on solid particle heat storage and release according to claim 1, characterized in that: The solid particle hot tank (17) is used to store high-temperature solid particles during the day, and its bottom is kept closed during the day.

6. A solar thermal power generation system based on solid particle heat storage and release according to claim 1, characterized in that: The cooler (23) is used to cool the carbon dioxide working fluid, and the compressor (19) is used to pressurize the low-temperature carbon dioxide. After being pressurized by the compressor (19), the carbon dioxide working fluid is divided into two streams: one stream flows into the cold-heat exchanger (22) to heat the pressurized carbon dioxide once; the other stream enters the gas buffer layer (3). After being pressurized and heated by the compressor (19), the cold-heat exchanger (22) and the solid particle-carbon dioxide heat exchange device, the carbon dioxide working fluid is used to drive the turbine (20) and drive the generator (21) to generate electricity.

7. A solar thermal power generation system based on solid particle heat storage and release according to claim 1, characterized in that: The solar thermal power generation system based on solid particle heat storage and release includes a first belt (11), a second belt (12), a third belt (13) and a fourth belt (16), as well as a first conveyor (14) and a second conveyor (15). The first belt (11) is connected to the second conveyor (15), and the third belt (13) is connected to the first conveyor (14). The first conveyor (14) and the second conveyor (15) are arranged coaxially. The second conveyor (15) conveys the solid particles upward to the fourth belt (16), and the fourth belt (16) then conveys the solid particles to the solid particle inlet (8). The first belt (11) is used to transport the heat-exchanged solid particles to the second conveyor (15); the fourth belt (16) is used to further transport the solid particles transported by the second conveyor (15) to the solid particle inlet (8); the second belt (12) is used to transport low-temperature solid particles to the cold tank; the third belt (13) is used to transport low-temperature solid particles to the first conveyor (14) during the day and to transport high-temperature solid particles to the first conveyor (14) at night.

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