Circulating lift solid particle receiver and tower solar thermal power generation system

Abstract

This invention discloses a circulating-lift solid particle heat absorber and a tower-type solar thermal power generation system. The heat absorber includes a heat absorber cavity with a heat absorption port. The heat absorber also includes at least a first particle inlet tank, a second particle inlet tank, and a lifting system. The heat absorber cavity includes at least a first particle inlet and a second heat absorber particle inlet. The first particle inlet tank is connected to the first particle inlet, and particles pass through the first particle inlet to form a first particle curtain. The second particle inlet tank is connected to the second heat absorber particle inlet, and particles pass through the second particle inlet to form a second particle curtain. The first particle curtain is located between the heat absorption port and the second particle curtain. Solar radiation entering the heat absorber cavity through the heat absorption port passes through the first particle curtain and is absorbed by the second particle curtain. After absorbing heat, the first particle curtain enters the second particle inlet tank via the lifting system. This heat absorber can increase the particle outlet temperature and improve the heat absorption efficiency.

Description

Technical Field

[0001] This invention belongs to the field of solar thermal power generation, and particularly relates to a circulating lift-type solid particle heat absorber and a tower-type solar thermal power generation system. Background Technology

[0002] Solar energy, as a clean and renewable energy source, is being used more and more widely. In particular, concentrated solar power (CSP) technology is an emerging solar energy utilization technology following photovoltaic (PV) power generation. Among these, tower CSP technology has attracted widespread attention due to its advantages of inexpensive and efficient energy storage and stable and smooth power output. A tower CSP power plant mainly consists of a heliostat field, a receiver, a thermal storage system, and a turbine generator set. The receiver system, as a key component in converting solar energy into thermal energy, is crucial for ensuring its high-performance and safe operation, which is an important aspect of CSP research and application.

[0003] Traditional solar thermal absorbers use binary molten salt as the heat absorption medium. When the operating temperature is below 250℃, the molten salt solidifies, and when the temperature exceeds 565℃, it decomposes, affecting both the safe operation of the system and reducing its efficiency. To improve the efficiency of solar thermal power generation and reduce its cost, researching novel high-temperature solar thermal absorber structures is crucial. Researchers have discovered that using ceramic particles or other granules as the heat storage medium can achieve a heat storage temperature of around 1000℃, significantly improving the efficiency of the hotspots at the back end of solar thermal power plants. To fully utilize the heat storage characteristics of solid particles, scholars at home and abroad have proposed various high-temperature particle heat absorber structures in recent years. Sandia National Laboratories in the United States proposed a free-falling particle heat absorber, demonstrating the feasibility of the particle heat absorber concept. However, the particles in the free-falling particle heat absorber fall too fast, resulting in a short residence time under light and a small temperature rise. Chinese patent CN105135716A disclosed a quartz glass tube particle heat absorber, which slows down the falling speed of particles by setting an insert inside the tube. However, due to the poor high-temperature resistance of quartz glass, it cannot meet the requirement of the particle heat absorber operating at a temperature of 700-1000℃ for a long time. Summary of the Invention

[0004] This invention provides a circulating lifting solid particle heat absorber and a tower-type solar thermal power generation system. The heat absorber extends the heating time of the particles through secondary or multiple cyclic heating, increases the particle outlet temperature, and improves the heat absorption efficiency. Multiple particle inlets are set to form multiple rows of particle curtains. The second row of particle curtains and subsequent particle curtains can further absorb solar radiation and thermal radiation passing through the first row of particle curtains, significantly improving the particles' ability to absorb incident radiation, thereby improving the heat absorption efficiency of the heat absorber.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A circulating lifting solid particle heat absorber includes a heat absorber cavity, the heat absorber cavity includes a heat absorption port, and the heat absorber further includes at least a first particle inlet tank, a second particle inlet tank and a lifting system, the heat absorber cavity includes at least a first particle inlet and a second particle inlet;

[0007] The first particle inlet tank is connected to the first particle inlet, and particles pass through the first particle inlet to form a first particle curtain; the second particle inlet tank is connected to the second particle inlet, and particles pass through the second particle inlet to form a second particle curtain; the first particle curtain is located between the heat absorption port and the second particle curtain, and solar radiation entering the heat absorber cavity through the heat absorption port passes through the first particle curtain and is absorbed by the second particle curtain.

[0008] After absorbing heat, the particles of the first particle curtain enter the second particle inlet tank via the elevator system.

[0009] The heat absorber cavity is provided with at least a first inclined plate. The first inclined plate includes a first upper inclined plate and a first lower inclined plate that are inclined and stacked in the same direction. A plurality of first upper partitions are provided on the first upper inclined plate, and a plurality of first lower partitions are provided on the first lower inclined plate. The first upper partitions and the first lower partitions extend along the first upper inclined plate and the first lower inclined plate, respectively.

[0010] The first upper inclined plate is provided with a first upper particle collection area and a first particle discharge port corresponding to the first particle curtain; the first lower inclined plate is provided with a first lower particle collection area corresponding to the first particle discharge port;

[0011] The particles flowing through the first upper inclined plate and the first lower inclined plate flow in opposite directions during their descent.

[0012] A first inclined plate is installed on the heat absorber cavity to slow down the falling speed of the particle curtain. The first inclined plate includes an upper inclined plate and a lower inclined plate stacked on top of each other. Several upper baffles are installed on the upper inclined plate and several lower baffles are installed on the lower inclined plate. The upper baffles form a particle flow channel on the upper inclined plate and the lower baffles form a particle flow channel on the lower inclined plate. The upper and lower inclined plates cooperate to transform the middle particles of the first particle curtain formed by the first particle inlet into the particles on both sides of the second particle curtain formed by the second particle inlet, and the particles on both sides of the first particle curtain into the middle particles of the second particle curtain, thereby improving the uniformity of particle temperature.

[0013] The first inclined plate is located at the lower part of the first particle curtain.

[0014] The first upper particle collection area is located on one side of the first upper inclined plate, and the first particle discharge port is located on the other side of the first upper inclined plate; the upper end of the first upper partition is located in the first upper particle collection area, and the lower end of the first upper partition is located on the side close to the first particle discharge port.

[0015] The upper end of the first lower partition is located in the first lower particle collection area, and the lower end of the first lower partition is located on the side close to the first upper particle collection area.

[0016] The heat absorber also includes a first collection hopper. The first particle curtain flows through the first inclined plate and enters the first collection hopper. The first collection hopper is located at the lower part of the heat absorber cavity. The elevator system is located at the lower part of the first collection hopper. The first collection hopper is connected to the elevator system.

[0017] The elevator system includes a hopper connected to the first collection hopper, and the elevator system lifts the particles in the hopper to the second particle inlet tank.

[0018] The first collecting hopper, the hopper, and the second particle inlet tank are all equipped with the same number of second partitions. The second partitions divide the inner cavity of the first collecting hopper, the hopper, and the second particle inlet tank into different areas. The inner cavity of the first collecting hopper, the hopper, and the second particle inlet tank is divided into the same number of areas to ensure that the relative position of the particles between the areas remains unchanged after the first particle curtain flows through the first inclined plate.

[0019] The heat absorber also includes a second collection hopper, into which the particles of the second particle curtain enter after absorbing solar radiation.

[0020] A tower-type solar thermal power generation system includes the aforementioned circulating lift-type solid particle receiver.

[0021] Because the present invention adopts the above technical solution, it has the following advantages and positive effects compared with the prior art:

[0022] (1) In the embodiments of the present invention, two or more particle inlets are provided. By lifting the particles that have fallen once to the particle inlet of the absorber again for cyclic heating, the particle heating time is extended and the particle temperature is increased. By setting two or more rows of curtains in front and behind, the second row and subsequent particle curtains can further absorb the solar radiation passing through the previous row of particle curtains and the heat radiation of the previous particle curtain, which significantly improves the ability of the particles to absorb incident radiation, thereby improving the heat absorption efficiency of the absorber.

[0023] (2) In the embodiments of the present invention, by setting a first inclined plate on the heat absorber cavity, the falling speed of the particle curtain can be slowed down. The first inclined plate includes a first upper inclined plate and a first lower inclined plate stacked on top of each other. A plurality of first upper partitions are set on the first upper inclined plate and a plurality of first lower partitions are set on the first lower inclined plate. The first upper partitions form a particle flow channel on the first upper inclined plate and the first lower partitions form a particle flow channel on the first lower inclined plate. The first upper inclined plate and the first lower inclined plate cooperate, and the middle particles of the first particle curtain formed by the first particle inlet become the particles on both sides at the second particle inlet. The particles on both sides of the first particle curtain become the middle particles of the second particle curtain, thereby improving the uniformity of particle temperature. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the circulating lifting solid particle heat absorber of Embodiment 1 of the present invention;

[0025] Figure 2 This is a schematic diagram of the structure of the first particle inlet and the second particle inlet in Embodiment 1 of the present invention;

[0026] Figure 3 This is a top view of one embodiment of the first upper inclined plate of Embodiment 1 of the present invention;

[0027] Figure 4 As in Embodiment 1 of the present invention Figure 2 Top view of the first lower inclined plate;

[0028] Figure 5 This is a top view of another embodiment of the first upper inclined plate of Embodiment 1 of the present invention;

[0029] Figure 6 As in Embodiment 1 of the present invention Figure 4 Top view of the first lower inclined plate;

[0030] Figure 7 This is a schematic diagram of the flow channel baffle of the hopper in the elevator system of Embodiment 1 of the present invention;

[0031] Figure 8 This is a schematic diagram of the flow channel baffle of the second particle inlet tank of the present invention.

[0032] Explanation of reference numerals in the attached drawings: 1-Absorber cavity; 2-Absorber port; 3-First particle inlet tank; 4-Second particle inlet tank; 5-First particle curtain; 6-Second particle curtain; 7-First upper inclined plate; 701-First upper partition plate; 702-First upper particle collection area; 703-First particle discharge port; 8-First lower inclined plate; 801-First lower partition plate; 802-First lower particle collection area; 9-First collection hopper; 10-Second collection hopper; 11-Collection hopper partition plate; 12-Elevator system; 1201-Hopper; 13-First particle inlet; 14-Second particle inlet; 15-Second partition plate; 16-Third particle curtain. Detailed Implementation

[0033] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a further detailed account of the circulating lift-type solid particle heat absorber and tower-type solar thermal power generation system proposed in this invention. The advantages and features of this invention will become clearer from the following description.

[0034] Example 1

[0035] See Figure 1-2 A circulating lifting solid particle heat absorber includes a heat absorber cavity 1. The heat absorber cavity 1 reduces the influence of the external environment and the convection and radiation losses of the heat absorber, and also keeps the particles inside the cavity warm. The heat absorber cavity 1 includes a heat absorption port 2, through which solar radiation enters the interior of the heat absorber cavity 1. The heat absorber also includes at least a first particle inlet tank 3, a second particle inlet tank 4, and a lifting system 12. The first particle inlet tank 3 and the second particle inlet tank 4 are located in the upper part of the heat absorber cavity 1, and the lifting system 12 is located in the lower part of the heat absorber cavity 1. Accordingly, the heat absorber cavity 1 includes at least a first particle inlet 13 and a second particle inlet 14.

[0036] The first particle inlet tank 3 is connected to the first particle inlet 13, and particles pass through the first particle inlet 13 to form a first particle curtain 5; the second particle inlet tank 4 is connected to the second particle inlet 14, and particles pass through the second particle inlet 14 to form a second particle curtain 6; the first particle curtain 5 is located between the heat absorption port 2 and the second particle curtain 6, and solar radiation entering the heat absorber cavity 1 through the heat absorption port 2 is absorbed by the second particle curtain 6 after passing through the first particle curtain 5.

[0037] After the particles of the first particle curtain 5 absorb heat, they enter the second particle inlet tank 4 through the elevator system 12. After the particles of the second particle curtain 6 absorb heat, they flow out of the heat absorber cavity 1 for temporary storage.

[0038] The heat absorber can be equipped with two or more circulating particle inlet tanks, and the heat absorber cavity 1 is equipped with multiple particle inlets accordingly. After the particle curtain formed by each circulation absorbs heat, it is sent to the first particle inlet tank 3 through the elevator system 12 and enters the heat absorber cavity 1 to absorb heat again, extending the particle heating time and increasing the particle temperature. The particle curtain of the last circulation is stored after absorbing heat.

[0039] Since the absorber particle inlets are all strip-shaped openings, multiple absorber particle inlets are arranged one after the other, forming two or more rows of particle curtains. The second and subsequent rows of particle curtains can absorb transmitted solar radiation and further absorb the heat radiation from the previous row of particle curtains, significantly improving the particles' ability to absorb incident radiation, thereby increasing the absorber's heat absorption efficiency. In this embodiment, the first particle inlet 13 represents the particle inlets arranged in the last row of multiple absorber particle inlets, and the second particle inlet 14 represents the particle inlet arranged in the last row.

[0040] Due to the uneven energy distribution of incident radiation, the particles in the middle of the particle curtain in the drop-type particle receiver have a high temperature, while the particles on both sides have a low temperature, resulting in a large temperature difference between the particles. Moreover, existing particle receiver systems all suffer from the drawback of excessive temperature difference between particles at the receiver outlet, leading to uneven particle temperature distribution within the storage tank and significantly increasing the difficulty of heat preservation.

[0041] Therefore, in order to improve the disadvantage of excessive temperature difference between particles, at least a first inclined plate is provided inside the absorber cavity 1. That is, except for the particle curtain formed by the last row of absorber particle inlet, the area through which the other particle curtains pass is provided with a first inclined plate. The first inclined plate through which the first row of particle curtains near the heat absorption port 2 of the absorber cavity 1 passes is provided at the lower part of the heat absorption port 2. The first inclined plate includes a first upper inclined plate 7 and a first lower inclined plate 8 that are inclined and stacked in the same direction. A plurality of first upper partitions 701 are provided on the first upper inclined plate 7, and a plurality of first lower partitions 801 are provided on the first lower inclined plate 8. The first upper partitions 701 and the first lower partitions 801 extend along the first upper inclined plate 7 and the first lower inclined plate 8, respectively.

[0042] The first upper inclined plate 7 is provided with a first upper particle collection area 702 and a first particle discharge port 703 corresponding to the first particle curtain 5; the first lower inclined plate 8 is provided with a first lower particle collection area 802 corresponding to the first particle discharge port 703.

[0043] The particles flowing through the first upper inclined plate 7 and the first lower inclined plate 8 flow in opposite directions during the falling process. The particle curtain 5 formed by the first particle curtain 5 flowing through the first upper inclined plate 7 and the first lower inclined plate 8 is the third particle curtain 16.

[0044] A first inclined plate is provided on the heat absorber cavity 1 to slow down the falling speed of the particle curtain. The first inclined plate includes a first upper inclined plate 7 and a first lower inclined plate 8 stacked on top of each other. A plurality of first upper partitions 701 are provided on the first upper inclined plate 7, and a plurality of first lower partitions 801 are provided on the first lower inclined plate 8. The first upper partitions 701 form a particle flow channel on the first upper inclined plate 7, and the first lower partitions 801 form a particle flow channel on the first lower inclined plate 8. The first upper inclined plate 7 and the first lower inclined plate 8 cooperate to make the middle particles of the first particle curtain 5 become the particles on both sides of the third particle curtain 16, and the particles on both sides of the first particle curtain 5 become the middle particles of the third particle curtain 16, thereby improving the uniformity of particle temperature.

[0045] The process of transforming the middle particle of the first particle curtain 5 into particles on both sides, and transforming the particles on both sides into the middle particle, has two implementation methods in specific embodiments.

[0046] See Figure 3-4 In addition to 5-6, the first upper particle collection area 702 is located on one side of the first upper inclined plate 7, the first particle discharge port 703 is located on the other side of the first upper inclined plate 7, the upper end of the first upper partition plate 701 is located in the first upper particle collection area 702, and the lower end of the first upper partition plate 701 is located on the side close to the first particle discharge port 703.

[0047] The upper end of the first lower partition 801 is located in the first lower particle collection area 802, and the lower end of the first lower partition 801 is located on the side close to the first upper particle collection area 702.

[0048] Half of the particles in the first particle curtain 5 fall from the first particle discharge port 703 into the first lower particle collection area 802 of the first lower inclined plate 8. Since the upper end of the first lower partition plate 801 is located in the first lower particle collection area 802, and the lower end of the first lower partition plate 801 is located on the side close to the first upper particle collection area 702, the particles in the first lower particle collection area 802 slide out onto the side of the first lower inclined plate 8 away from the first particle discharge port 702. The other half of the particles in the first particle curtain 5 are collected in the first upper particle collection area 702. Since the lower end of the first upper partition plate 701 is located on the side close to the first particle discharge port 703, the particles collected in the first upper particle collection area 702 slide down onto the side of the first upper inclined plate 7 where the first particle discharge port 703 is located. Through the above arrangement, after the first particle curtain 5 flows through the first upper inclined plate 7 and the first lower inclined plate 8, the middle particles of the first particle curtain 5 become the particles on both sides of the third particle curtain 16, and the particles on both sides of the first particle curtain 5 become the middle particles of the third particle curtain 16.

[0049] See Figure 1 , Figure 7-8The heat absorber also includes a first collecting hopper 9. The first particle curtain 5 flows out of the heat absorber cavity 1 after passing through the first inclined plate and enters the first collecting hopper 9. The first collecting hopper 9 is located at the lower part of the heat absorber cavity 1. The elevator system 12 is located at the lower part of the first collecting hopper 9 and is connected to the elevator system 12.

[0050] The elevator system 12 includes a hopper 1201, which is connected to a first collection hopper. Particles in the first collection hopper 9 enter the hopper 1201, and the elevator system 12 lifts the hopper 1201 to the upper part of the second particle inlet tank 4.

[0051] To prevent particle mixing after heating and changing flow channels via the first inclined plate, the same number of second baffles 15 are arranged parallel to each other inside the first collecting hopper 9, hopper 1201, and second particle inlet tank 4. The second baffles 15 divide the inner cavities of the first collecting hopper 9, hopper 1201, and second particle inlet tank 4 into different regions. The number of regions within the cavities of the first collecting hopper 9, hopper 1201, and second particle inlet tank 4 is the same, ensuring that the relative positions of particles between regions remain unchanged after the first particle curtain 5 flows through the first inclined plate. The resulting third particle curtain 16 is then separated according to the different regions. The particles are collected and transported to the elevator system 12, and then enter different areas within the second particle inlet tank 4. This ensures that the particle positions of the second particle curtain 6 and the third particle curtain 16 are the same. Specifically, the middle particles with higher temperatures in the first particle curtain 5 become the particles on both sides of the second particle curtain 6, and the particles on both sides with lower temperatures in the first particle curtain 5 become the middle particles of the second particle curtain 6. The incident radiation from the second particle curtain 6 also exhibits a clear characteristic of high energy density in the middle and low energy density on both sides. Therefore, through flow channel transformation and secondary circulation heating, the uniformity of the outlet temperature of different particles is ensured.

[0052] The heat absorber also includes a second collection hopper 10. After the second particle curtain 6 absorbs heat, it enters the second collection hopper 10 for collection. The first collection hopper 9 and the second collection hopper 10 can be the same collection hopper, separated by a collection hopper partition 11 in the middle.

[0053] The operation of the absorber in this embodiment is as follows: After heat exchange, the low-temperature particles enter the first particle inlet tank 3 and then enter the absorber cavity 1 through the first particle inlet 13. Under the action of gravity, the low-temperature particles form the first particle curtain 5 and receive the solar radiation from the mirror field entering the absorber cavity 1 from the heat absorption port 2. After being heated, the particles fall to the first upper inclined plate 7 and the first lower inclined plate 8. Through flow channel transformation, the particles located in the middle flow channel and the particles located on both sides are interchanged. The particles after the flow channel transformation enter the first collection hopper 9, which is also equipped with a second partition plate, and are temporarily stored. At the same time, the particles in the same area will undergo further temperature mixing through heat conduction to ensure that the temperature of the particles in the same area is more uniform. When the hopper 1201 of the elevator system 12 (equipped with a second partition plate 15, the area structure corresponding to the first upper inclined plate 7 and the first lower inclined plate 8) runs to below the first collection hopper 9, the bottom valve of the first collection hopper 9 opens, and the particles enter the hopper 1201 and are lifted by the elevator system 12 to the second particle inlet tank 4. The second particle inlet tank 4 is also equipped with a second partition plate 15. Subsequently, the particles in the second particle inlet tank 4 enter the heat absorber cavity 1 through the second particle inlet 14 to form the second particle curtain 6. The middle of the second particle curtain 6... The particles correspond to those on both sides of the first particle curtain 5, while the particles on both sides of the second particle curtain 6 are those in the middle of the first particle curtain 5. Due to the characteristic of high energy flux density in the middle and low energy flux density on both sides of the incident radiation at the heat absorber 2, the particles in the middle of the first particle curtain 5 are heated to a high temperature, while the particles on both sides are heated to a low temperature. The high-temperature particles located on both sides of the second particle curtain 6 receive less incident radiation, while the low-temperature particles located in the middle of the second particle curtain 6 receive more solar radiation. This heat absorber achieves uniform heating of the particles. After uniform heating, the particles enter the second collection hopper 10 for temporary storage, completing the particle heat absorption process.

[0054] Example 2

[0055] A tower-type solar thermal power generation system includes the circulating lift-type solid particle heat absorber of Example 1.

[0056] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they shall still fall within the protection scope of the present invention.

Claims

1. A circulating lift solid particle heat sink comprising a heat sink cavity, the heat sink cavity comprising a heat sink port, characterized in that, The heat absorber further comprises a first particle inlet tank, a second particle inlet tank and an elevator system, and the heat absorber cavity comprises at least a first particle inlet and a second particle inlet; The first particle inlet tank is in communication with the first particle inlet, and particles form a first particle curtain through the first particle inlet; the second particle inlet tank is in communication with the second particle inlet, and particles form a second particle curtain through the second particle inlet; the first particle curtain is located between the heat absorption port and the second particle curtain, and solar radiation entering the heat absorber cavity through the heat absorption port is absorbed by the second particle curtain after passing through the first particle curtain; After the particles of the first particle curtain are absorbed, they enter the second particle inlet tank through the elevator system; The heat absorber cavity is internally provided with at least a first inclined plate, the first inclined plate comprises a first upper inclined plate and a first lower inclined plate which are inclined in the same direction and arranged in layers, a plurality of first upper partition plates are arranged on the first upper inclined plate, and a plurality of first lower partition plates are arranged on the first lower inclined plate, the first upper partition plates and the first lower partition plates respectively extend along the first upper inclined plate and the first lower inclined plate; The first upper inclined plate is provided with a first upper particle collection area corresponding to the first particle curtain and a first particle discharge port; The first lower inclined plate is provided with a first lower particle collection area corresponding to the first particle discharge port; The flow direction of the particles flowing through the first upper inclined plate and the first lower inclined plate is opposite during the falling process.

2. The circulating lift solid particle heat sink of claim 1, wherein, The first inclined plate is arranged at the lower part of the first particle curtain.

3. The circulating lift solid particle heat sink of claim 1 or 2, wherein, The first upper particle collection area is arranged on one side of the first upper inclined plate, and the first particle discharge port is arranged on the other side of the first upper inclined plate; the upper end of the first upper partition plate is arranged in the first upper particle collection area, and the lower end of the first upper partition plate is arranged on the side close to the first particle discharge port; The upper end of the first lower partition plate is arranged in the first lower particle collection area, and the lower end of the first lower partition plate is arranged on the side close to the first upper particle collection area.

4. The cyclically boosted solid particle heat sink of any one of claims 1 or 2, wherein, The heat absorber further comprises a first collection hopper, and the particles flowing through the first inclined plate enter the first collection hopper.

5. The circulating lift solid particle heat sink of claim 4, wherein, The elevator system comprises a hopper, and the elevator system lifts the particles in the hopper to the second particle inlet tank.

6. The cyclically boosted solid-particle heat sink of claim 5, wherein, The first collection hopper, the hopper and the second particle inlet tank are internally provided with the same number of second partition plates.

7. The cyclically boosted solid-particle heat sink of claim 4, wherein, The heat absorber further comprises a second collection hopper, and the particles of the second particle curtain enter the second collection hopper after absorbing solar radiation.

8. A tower-based solar thermal power generating system, characterized by, The heat absorber comprises the heat absorber according to any one of claims 1-7.

Images