Solid particle heat absorber

Abstract

The invention discloses a solid particle heat absorber. The solid particle heat absorber comprises a low-speed heat absorption section and a high-speed heat absorption section. The low-speed heat absorption section is communicated with the high-speed heat absorption section; wherein the average speed of solid particles passing through the low-speed heat absorption section is smaller than the average speed of solid particles passing through the high-speed heat absorption section. In a low-energy-flux-density area, the particles slowly pass through the area in the quartz tube, so that higher temperature rise and heat absorption efficiency in unit irradiation length are realized; in a high-energy flow density area, the particles rapidly pass through the area in the quartz tube, agglomeration caused by overheating of the particles is avoided, the working safety of the heat absorber is ensured, and high heat absorption efficiency is obtained.

Description

Technical Field

[0001] The present invention relates to a heat absorber in the field of solar thermal power generation, and particularly to a solid particle heat absorber. Background Art

[0002] Configuring large-capacity and low-cost energy storage enables solar thermal power generation systems to have the dual functions of peak shaving power supply and energy storage, and is an important part of building a new power system. The large-scale development of high-proportion solar thermal power generation can strongly support the construction of large-scale wind and solar bases in China, enabling the integrated project composed of solar thermal, photovoltaic and wind power to achieve stable and reliable output characteristics, and greatly reducing the loss of abandoned wind and light. Improving the operating temperature of solar thermal power generation systems is an important means to promote the annual power generation efficiency and reduce the power generation cost, and is the future development direction of solar thermal power generation.

[0003] Solid particles such as natural sand and ceramics have good chemical inertness and thermal stability at high temperatures of 1000 °C, and are ideal heat transfer fluids and energy storage media in the next-generation solar thermal power generation systems. In recent years, domestic and foreign researchers have carried out in-depth research on solar solid particle heat absorbers, proposed representative particle flow modes such as free-falling type, obstructed-falling type, moving bed type, fluidized bed type, rotary kiln type and inclined flow type, and carried out MW-level heat absorber technology demonstrations.

[0004] In the early 1980s, the Sandia National Laboratories in the United States first proposed a design prototype of a free-falling solid particle heat absorber. Solid particles freely fall from the top slit by gravity and form a particle curtain in the heat absorber. The high-concentration solar radiation energy projected by the heliostat field enters through the heat absorber opening to heat the particle curtain. This scheme has a simple structure, a fast particle falling speed, and can withstand an extremely high concentrated solar flux density. However, the existing schemes have the following disadvantages: 1) Particles in the heat absorber escape from the opening, resulting in particle loss, and cold air from the outside enters the heat absorber, causing a large convective heat loss; 2) The residence time of the particles is too short, and the temperature rise per single process is low. Therefore, it is necessary to repeatedly lift the particles for cyclic heating, and the lifting power consumption is large; 3) Most of the existing schemes use chamber heat absorbers, which are not suitable for large-scale annular heliostat fields. According to the literature "Performance evaluation of a high-temperature falling particle receiver", in 2015, the Sandia National Laboratories in the United States proposed a solid particle heat absorber using a "Λ"-shaped metal mesh structure as an obstruction structure, which can extend the residence time of solid particles during the falling process in the radiation heating area. At the same flow rate (3.3 kg / s) and average solar flux input (400 kW / m 2Under the condition of [[ID=]], the use of the "Λ"-shaped metal mesh blocking structure (210 °C) can increase the single-pass temperature rise by more than 2 times compared with the free-fall type (<100 °C). Therefore, it has the potential to significantly improve the efficiency of the heat absorber and reduce the lifting power consumption. However, the metal mesh structure used in this scheme is severely deformed under concentrated solar irradiation, so it is not suitable for the annular heliostat field either.

[0005] Therefore, a new solid particle heat absorber is needed. Summary of the Invention

[0006] In order to solve the above technical problems, the present invention proposes a solid particle heat absorber. The solid particle heat absorber of the present invention adopts the design concept of slow in the low energy flux density region and fast in the high energy flux density region. In the low energy flux density region, the particles slowly pass through this region in the quartz tube to achieve a higher temperature rise and heat absorption efficiency per unit irradiation length; in the high energy flux density region, the particles quickly pass through this region to obtain a higher heat absorption efficiency, avoid particle overheating and agglomeration, ensure the safety of the heat absorber operation, and obtain a higher heat absorption efficiency.

[0007] The present invention adopts the following technical solutions:

[0008] A solid particle heat absorber, the solid particle heat absorber includes a low-speed heat absorption section and a high-speed heat absorption section; the low-speed heat absorption section is connected to the high-speed heat absorption section; wherein the average speed of the solid particles passing through the low-speed heat absorption section is less than the average speed of passing through the high-speed heat absorption section;

[0009] Among them, the region where the concentrated solar energy flux density q is 1 / 3q max ≤q≤q max is the high-speed heat absorption section, and the region where the concentrated solar energy flux density q is 0≤q in ≤1 / 3q max is the low-speed heat absorption section, where q max is the peak energy flux density.

[0010] Among them, the average speed of the solid particles passing through the low-speed heat absorption section is not greater than 0.15 m / s, and the average speed of the solid particles passing through the high-speed heat absorption section is not greater than 2 m / s.

[0011] Among them, when the solid particle heat absorber is applied to the annular heliostat field, there are two low-speed heat absorption sections and one high-speed heat absorption section. The two low-speed heat absorption sections are respectively located at the upper end and the lower end of the high-speed heat absorption section.

[0012] Among them, the low-speed heat absorption section includes a heat absorption sleeve, the heat absorption sleeve includes an outer tube and an inner tube, both ends of the inner tube are open and closed, and the inner tube is fixedly nested inside the outer tube. The gap between the outer tube and the inner tube forms a channel for the solid particles to pass through.

[0013] Among them, the average diameter d of the solid particles p satisfies: 6 ≤ δ / d p ≤ 12, where δ is the gap thickness between the outer tube and the inner tube.

[0014] Preferably, a filling layer is provided on the backlight side of the gap between the outer tube and the inner tube.

[0015] Preferably, the low-speed heat absorption section includes a plurality of heat absorption sleeves, and the plurality of heat absorption sleeves are arranged annularly.

[0016] Preferably, the materials of the inner tube and the outer tube are quartz.

[0017] Among them, the high-speed heat absorption section includes a heat absorption tube for the solid particles to pass through.

[0018] Preferably, the heat absorption tube of the high-speed heat absorption section is a heat absorption tube group composed of a plurality of heat absorption tubes. The plurality of heat absorption tubes are connected in series. A buffer plate is provided between adjacent two heat absorption tubes, and a plurality of through holes are provided on the buffer plate.

[0019] Among them, a flow guiding member is provided in the heat absorption tube of the heat absorption tube group. The flow guiding member includes a horizontal plate and a vertical plate. The vertical plate is vertically and fixedly arranged on the horizontal plate. The vertical plate divides the horizontal plate into a light-facing side horizontal plate and a backlight side horizontal plate. Discharge holes are provided on the light-facing side horizontal plate.

[0020] Preferably, a flow guiding structure is further provided on the light-facing side horizontal plate; the flow guiding structure is a plurality of protruding portions protruding from the horizontal plate.

[0021] Preferably, a discharge hole array formed by a plurality of rows of discharge holes is provided on the light-facing side horizontal plate, and a flow guiding structure array formed by a plurality of rows of flow guiding structure holes is provided on the light-facing side horizontal plate; the discharge holes and the flow guiding structures are arranged at intervals.

[0022] Preferably, the high-speed heat absorption section includes a plurality of heat absorption tubes, and the plurality of heat absorption tubes are arranged annularly.

[0023] Preferably, the material of the heat absorption tube is quartz, and the material of the flow guiding member is ceramic.

[0024] Preferably, the solid particle heat absorber further includes a hoist, a low-temperature particle storage tank, a first flow guiding pipe, a second flow guiding pipe, a third flow guiding pipe, and a high-temperature particle storage tank; the low-temperature particle storage tank is communicated with the first low-speed heat absorption section through the first flow guiding pipe, the first low-speed heat absorption section is communicated with the high-speed heat absorption section through the second flow guiding pipe, the high-speed heat absorption section is communicated with the second low-speed heat absorption section through the third flow guiding pipe, and the second low-speed heat absorption section is communicated with the high-temperature particle storage tank.

[0025] Preferably, a first valve is provided between the low-temperature particle storage tank and the first low-speed heat absorption section, a second valve is provided between the first low-speed heat absorption section and the high-speed heat absorption section, and a third valve is provided between the second low-speed heat absorption section and the high-temperature particle storage tank;

[0026] And / or, a tapered section is provided between the high-speed heat absorption section and the second low-speed heat absorption section;

[0027] And / or, a first funnel and a second funnel are respectively provided at the bottoms of the first low-speed heat absorption section and the second low-speed heat absorption section.

[0028] Preferably, a heat insulation layer is provided on the backlight side of the solid particle heat absorber, and a heat insulation layer is provided on the non-heat absorption section of the light-facing side of the solid particle heat absorber.

[0029] The solid particle heat absorber of the present invention has the following advantages:

[0030] (1) In the present invention, the solid particles freely fall in the high-energy flow region to achieve rapid passage, and accumulate and fall in the low-energy flow region to achieve slow passage; therefore, it can avoid agglomeration caused by overheating of the particles during high-energy flow density heating, and at the same time, it can also avoid the insufficient heat absorption efficiency caused by too low single-pass temperature rise of the particles during low-energy flow density heating.

[0031] (2) In the present invention, the solid particles freely fall in an array of particle beams in each quartz tube of the heat absorption tube group in the high-speed heat absorption section, which can effectively suppress the convective loss caused by the outside air, can avoid particle loss, can effectively achieve volumetric heating, and is suitable for large-scale annular heliostat fields;

[0032] (3) In the present invention, the first heat absorption section and the third heat absorption section are constructed with a moving bed particle flow channel in the form of a quartz sleeve, so the thickness of the particle layer is uniform, and the phenomenon of particle flow blockage can be effectively avoided. Description of the Drawings

[0033] Figure 1 is an overall schematic diagram of a solid particle heat absorber of the present invention;

[0034] Figure 2 is an overall schematic diagram of the flow guiding member of the present invention;

[0035] Figure 3 is an overall layout schematic diagram of an embodiment of the low-speed heat absorption section of the solid particle heat absorber of the present invention;

[0036] Figure 4 is an overall layout schematic diagram of an embodiment of the high-speed heat absorption section of the solid particle heat absorber of the present invention.

[0037] Among them, the reference numerals are as follows: 1 - elevator, 2 - low-temperature particle storage tank, 3 - solid particles, 4 - first valve. 5a - first thermal insulation layer, 5b - second thermal insulation layer, 5c - third thermal insulation layer, 5d - fourth thermal insulation layer, 5e - fifth thermal insulation layer, 6 - first diversion pipe, 7a - first flange, 7b - second flange, 7c - third flange, 7d - fourth flange, 7e - fifth flange, 7f - sixth flange, 7g - seventh flange, 8 - first outer pipe, 9 - first inner pipe, 10 - first filling layer, 11 - first funnel, 12 - second valve, 13 - second diversion pipe, 14 - heat absorption pipe, 15 - diversion member, 15a - horizontal plate, 15b - vertical plate, 15c - discharge hole, 15d - diversion structure, 15e - fixing hole, 16 - tapered section, 17 - third diversion pipe, 18 - second outer pipe, 19 - second inner pipe, 20 - second filling layer, 21 - second funnel, 22 - third valve, 23 - high-temperature particle storage tank, 24 - fourth valve, 25 - thin strip. Specific embodiments

[0038] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0039] As Figure 1 shown, a solid particle heat absorber, the solid particle heat absorber includes a low-speed heat absorption section and a high-speed heat absorption section; the low-speed heat absorption section is connected to the high-speed heat absorption section and the low-speed heat absorption section is located at the upper end of the high-speed heat absorption section; wherein the average speed of the solid particles passing through the low-speed heat absorption section is less than the average speed of passing through the high-speed heat absorption section; wherein, the concentrated solar energy flux density q is 1 / 3q max ≤q≤q max The area is the high-speed heat absorption section, and the concentrated solar energy flux density q is 0≤q in ≤1 / 3q max The area is the low-speed heat absorption section, wherein, q max is the peak energy flux density.

[0040] Research findings show that locally excessive energy flux density is the main cause of overheating damage to the heat absorber. Based on this, the present invention is designed to have different average velocities of solid particles passing through in different concentrated solar energy flux density regions. Specifically, in the low energy flux density region, the particles pass through this region slowly, achieving a higher temperature rise and heat absorption efficiency per unit irradiation length; in the high energy flux density region, the particles pass through this region quickly, obtaining a higher heat absorption efficiency, avoiding agglomeration caused by particle overheating, ensuring the safety of the heat absorber operation, and obtaining a higher heat absorption efficiency.

[0041] In actual use, the high-speed heat absorption section and the low-speed heat absorption section can be designed according to the energy density distribution law.

[0042] As a preferred implementable mode, when applied to a circular heliostat field, the inventor found that the solar rays reflected by the circular heliostat field form an energy flux distribution law of "high in the middle and low at both ends" in the height direction of the heat absorber, and its peak energy flux density exceeds 1.2 MW / m 2 , corresponding to the energy flux distribution law of "high in the middle and low at both ends", when the solid particle heat absorber of the present invention is applied to a circular heliostat field, there are two low-speed heat absorption sections and one high-speed heat absorption section for the solid particle heat absorber. Among them, one low-speed heat absorption section is located at the upper end of the high-speed heat absorption section, and the other low-speed heat absorption section is located at the lower end of the high-speed heat absorption section. For the convenience of design and manufacture, the structures of the two low-speed heat absorption sections are exactly the same. The solid particle heat absorber of this embodiment includes three heat absorption sections from top to bottom, namely the first low-speed heat absorption section, the high-speed heat absorption section, and the second low-speed heat absorption section; in the first low-speed heat absorption section and the second low-speed heat absorption section, the solid particles 3 flow slowly and receive the irradiation of the low energy flux density region in the concentrated solar energy; in the high-speed heat absorption section, the solid particles 3 flow quickly and receive the irradiation of the high energy flux density region in the concentrated solar energy. The range of the concentrated solar energy flux density corresponding to the operation of the first low-speed heat absorption section and the second low-speed heat absorption section in this embodiment is: 0 ≤ q in ≤ 1 / 3q max , and the range of the concentrated solar energy flux density corresponding to the operation of the high-speed heat absorption section is: 1 / 3q max ≤ q in ≤ q max , where q max is the peak energy flux density.

[0043] Preferably, the average velocity of the solid particles passing through the low-speed heat absorption section is not greater than 0.15 m / s, and the average velocity of the solid particles passing through the high-speed heat absorption section is not greater than 2 m / s. In this embodiment, as long as the movement velocity of the solid particles in the corresponding energy flux density region is controlled within a certain range, it can be achieved through various structures.

[0044] See Figure 1, a solid particle heat absorber, comprising a hoist 1, a low-temperature particle storage tank 2 and a high-temperature particle storage tank 23, and the hoist 1 is respectively communicated with the low-temperature particle storage tank 2 and the high-temperature particle storage tank 23. The solid particles 3 flow from the low-temperature particle storage tank 2 into the first low-speed heat absorption section, the high-speed heat absorption section and the second low-speed heat absorption section in sequence and then flow into the high-temperature particle storage tank 23. The hoist 1 lifts the solid particles in the high-temperature particle storage tank 23 to the low-temperature particle storage tank 2 to achieve cyclic heating until the average temperature of the solid particles 3 in the high-temperature particle storage tank 23 reaches a predetermined temperature (i.e., an ideal high-temperature state). Preferably, the low-temperature particle storage tank 2 is located at the upper part of the heat absorption section, and the high-temperature particle storage tank 23 is located at the lower part of the heat absorption section. After the fourth valve 24 is opened, the hoist 1 on the backlight side of the heat absorption section realizes the lifting of the solid particles 3 for cyclic heating.

[0045] It is required that the solid particles 3 have good chemical stability and fluidity at high temperatures. The preferred shape is spherical, and it can also be ellipsoidal or other shapes. The average diameter d p has a range of 200 μm ≤ d p ≤ 1 mm. The solid particles do not contain fine powder to avoid polluting the inner wall surface of the quartz tube in each heat absorption section. Preferred solid particles include sintered bauxite particles, silicon carbide particles, etc. In order to improve the thermal efficiency of the heat absorber, the preferred solid particles should have a high packing thermal conductivity and an average absorptivity under the solar spectrum.

[0046] In one embodiment, in order to make the solid particles pass through the low-speed heat absorption section at a low speed, in this embodiment, the solid particles pass through the low-energy flux density region in a stacked falling manner. The low-speed heat absorption section includes a heat absorption sleeve, and the heat absorption sleeve includes a first outer tube 8 and a first inner tube 9. Both ends of the first inner tube 9 are closed, and the first inner tube 9 is fixedly nested inside the first outer tube 8. The gap between the first outer tube 8 and the first inner tube 9 forms a channel for the solid particles to pass through. See Figure 1 , a first funnel 11 and a second valve 12 are arranged between the first low-speed heat absorption section and the high-speed heat absorption section. The function of the funnel is to realize stacked falling inside the tube, and the function of the valve is to adjust the speed of the stacked falling.

[0047] Preferably, as Figure 3 shown, the ends of the gap between the first outer tube 8 and the first inner tube 9 are fixed by welding with thin strips 25 to form a set of quartz sleeves. The thin strips 25 are preferably quartz thin strips.

[0048] In this embodiment, since the solid particles can only flow in the gap, the solid particles slowly pass through the low-energy flux density region in a stacked falling manner in the heat absorption sleeve of the low-speed heat absorption section. At the same time, a valve can also be arranged at the outlet end of the heat absorption sleeve to control the speed of the solid particles and the residence time in the low-speed heat absorption section by controlling the opening degree of the valve.

[0049] Preferably, the average diameter d of the solid particles 3 p satisfies: 6 ≤ δ / d p ≤ 12, where δ is the gap thickness between the first outer tube and the first inner tube. Such a setting can ensure the passing speed of the solid particles on the one hand and avoid the accumulation of solid particles on the other hand.

[0050] More preferably, a first filling layer 10 is provided on the backlight side of the gap between the first outer tube 8 and the first inner tube 9. Specifically, a first filling layer 10 is provided on the annular backlight side of the gap between the first outer tube 8 and the first inner tube 9. In the present invention, a filling layer is provided in the backlight side part of the gap, aiming to prevent the solid particles from flowing from the backlight side. Such a setting is to achieve sufficient heat absorption and ensure the heat absorption efficiency of the solid particles and the temperature uniformity in the particle layer as much as possible under the condition of passing through the low energy flux density area at a low speed. The first filling layer 10 fills the semi-circular backlight side gap of the heat absorption sleeve in the low-speed heat absorption section, and the solid particles 3 are heated by the focused solar energy when accumulating and falling in the semi-circular light-facing side gap of the heat absorption sleeve in the low-speed heat absorption section.

[0051] In order to make the solid particle heat absorber of the present invention applicable to a large-scale annular mirror field, see Figure 3 , in this embodiment, the low-speed heat absorption section includes a plurality of heat absorption sleeves, and the plurality of heat absorption sleeves are arranged in a ring. As Figure 3 shown, the low-speed heat absorption section includes a plurality of heat absorption sleeves arranged circumferentially in a ring, and a filling layer is provided in the backlight side part of the gap of each heat absorption sleeve.

[0052] The arrangement of the second low-speed heat absorption section is similar to that of the first low-speed heat absorption section. Specifically, see Figure 1 , the second low-speed heat absorption section includes a second heat absorption sleeve, and the second heat absorption sleeve includes a second outer tube 18, a second inner tube 19 and a second filling layer 20. The second inner tube 19 is fixed inside the second outer tube 18, and the second inner tube 19 is preferably coaxially arranged with the second outer tube 18. The second filling layer 20 is provided in the backlight side part of the gap between the second inner tube 19 and the second outer tube 18.

[0053] In this embodiment, the outer tubes (the first outer tube and the second outer tube) and the inner tubes (the first inner tube and the second inner tube) are both made of quartz.

[0054] Preferably, in order to enable the solid particles to quickly pass through the high energy flux density area, in this embodiment, the solid particles freely fall in the high-speed heat absorption section. Specifically, the high-speed heat absorption section includes a heat absorption tube 14 for the solid particles to pass through. After the solid particles flow into the high-speed heat absorption section through the low-speed heat absorption section, they freely fall in the heat absorption tube of the high-speed heat absorption section, so that they can quickly pass through the heat absorption tube, avoiding excessive residence time and causing particle overheating and agglomeration. The heat absorption tube 14 is preferably a quartz tube.

[0055] Preferably, the heat absorption tubes in the high-speed heat absorption section are a heat absorption tube group composed of multiple heat absorption tubes. The multiple heat absorption tubes are connected in series, and a buffer plate is arranged between adjacent two heat absorption tubes. A plurality of through holes are arranged on the buffer plate. In this embodiment, multiple heat absorption tubes are provided, and adjacent heat absorption tubes are separated by buffer plates, or in other words, multiple buffer plates are arranged in the heat absorption tubes of this embodiment. Such an arrangement reduces the speed of the solid particles when they fall onto the buffer plate, which can adjust the flow speed of the solid particles in the heat absorption tubes and prevent their excessive speed from affecting the heat absorption efficiency.

[0056] As a more preferable implementation manner, refer to Figure 2 , in this embodiment, a flow guiding member 15 is arranged in the heat absorption tube 14 of the heat absorption tube group. The flow guiding member 15 includes a horizontal plate 15a and a vertical plate 15b. The vertical plate 15b is vertically and fixedly arranged on the horizontal plate 15a. The vertical plate 15b divides the horizontal plate into a light-facing side horizontal plate and a backlight-side horizontal plate. A discharge hole 15c is arranged on the light-facing side horizontal plate. Specifically, fixing holes 15e are arranged at the ends of the horizontal plate to facilitate the fixing of the flow guiding member 15 and the heat absorption tube 14 by a flange 7e; the vertical plate 15b is rectangular, its length is the same as that of the heat absorption tube 14, and its width is the same as the inner diameter of the heat absorption tube 14. The arrangement of the vertical plate enables the solid particles to pass through as much as possible on the light-facing side of the heat absorption tube, thereby ensuring the heat absorption efficiency. After the solid particles enter the heat absorption tube, they freely fall from a part on the light-facing side of the heat absorption tube onto the horizontal plate of the flow guiding member, and then flow out from the discharge hole 15c of the horizontal plate of the flow guiding member. Due to the action of the flow guiding member 15, every time the solid particles 3 fall onto the horizontal plate 15a in the flow guiding member 15, that is, when they fall by the height of a single quartz tube, the speed of the solid particles 3 is reduced to 0 and they flow into the next quartz tube to freely fall again. It should be noted that the flow guiding member and the buffer plate can be arranged simultaneously, or only the flow guiding member or only the buffer plate can be arranged.

[0057] Among them, the horizontal plate 15a and the vertical plate 15b in the flow guiding member 15 are welded into one body. The flow guiding member 15 is made of a ceramic with a high reflectivity in the solar spectrum. Most of the focused solar light entering each heat absorption tube in the heat absorption tube group is directly intercepted by the particle beam array, and a small part of the focused solar light can still be projected onto the particle beam array after being reflected by the vertical plate 15b. Therefore, efficient absorption of solar energy is achieved. The solid particles 3 flowing out from the first low-speed heat absorption section freely fall in each heat absorption tube of the heat absorption tube group in the high-speed heat absorption section.

[0058] Such as Figure 4As shown, the vertical plate 15b of the flow guiding member 15 equally divides the internal space of the heat absorption tube group into two parts, namely the light-facing side and the backlight side. When the solid particles 3 freely fall in the heat absorption tube group in an array-like particle beam, they are heated by the focused solar energy. The flow guiding member 15 is made of ceramics with a high reflectivity in the solar spectrum. Most of the focused solar rays entering each heat absorption tube in the heat absorption tube group are directly intercepted by the particle beam array, and a small part of the focused solar rays can still be projected onto the particle beam array after being reflected by the vertical plate 15b, thus achieving efficient absorption of solar energy.

[0059] More preferably, referring to Figure 2 , a flow guiding structure 15d is further provided on the light-facing side horizontal plate; the flow guiding structure 15d is a plurality of protruding parts protruding from the horizontal plate. The protruding parts are preferably conical.

[0060] Among them, referring to Figure 2 , a discharge hole array formed by a plurality of rows of discharge holes is provided on the light-facing side horizontal plate, and a flow guiding structure array formed by a plurality of rows of flow guiding structure holes is provided on the light-facing side horizontal plate; the discharge holes and the flow guiding structures are arranged at intervals. The function of the discharge hole array is to form a particle beam array in each heat absorption tube of the heat absorption tube group to fully realize the "volume absorption" of the solid particles 3 to the concentrated solar energy. The function of the conical flow guiding structure array is to avoid obvious particle accumulation on the light-facing side of the horizontal plate 15a and facilitate the solid particles 3 to flow into the next heat absorption tube of the heat absorption tube group through the discharge holes 15c.

[0061] In order to make the solid particle heat absorber of the present invention applicable to a large-scale annular mirror field, referring to Figure 4 , the high-speed heat absorption section includes a plurality of heat absorption tubes, and the plurality of heat absorption tubes are arranged in a ring.

[0062] Referring to Figure 1 , the solid particle heat absorber of this embodiment further includes an elevator 1, a low-temperature particle storage tank 2, a first flow guiding pipe 6, a second flow guiding pipe 13, a third flow guiding pipe 17 and a high-temperature particle storage tank 23; the low-temperature particle storage tank 2 is connected to the first low-speed heat absorption section through the first flow guiding pipe 6, the first low-speed heat absorption section is connected to the high-speed heat absorption section through the second flow guiding pipe 13, the high-speed heat absorption section is connected to the second low-speed heat absorption section through the third flow guiding pipe 17, and the second low-speed heat absorption section is connected to the high-temperature particle storage tank 23. The purpose of setting the flow guiding pipes is to enable the solid particles to better enter the corresponding positions (mainly the light-facing side) of the heat absorption section.

[0063] In one embodiment, a first valve 4 is provided between the low-temperature particle storage tank 2 and the first low-speed heat absorption section, a second valve 12 is provided between the first low-speed heat absorption section and the high-speed heat absorption section, and a third valve 22 is provided between the second low-speed heat absorption section and the high-temperature particle storage tank. The purpose of setting the valves is to control the flow rate of the solid particles so as to control the passing speed of the solid particles. In this embodiment, no valve is provided between the high-speed heat absorption section and the second low-speed heat absorption section, aiming to save equipment. At the same time, due to the action of the buffer plate and / or the flow guiding member in the high-speed heat absorption section, the initial speed of the solid particles entering the second low-speed heat absorption section tends to be 0, and the solid particles entering the second low-speed heat absorption section already have a certain temperature, and the structure of the second low-speed heat absorption section is the same as that of the first low-speed heat absorption section, and their speeds are also basically the same. Therefore, it is not necessary to set a valve to control the flow rate of the solid particles entering the second low-speed heat absorption section.

[0064] Furthermore, to facilitate the smooth inflow of solid particles in the high-speed heat absorption section into the second low-speed heat absorption section, a tapered section 16 is provided between the high-speed heat absorption section and the second low-speed heat absorption section in this embodiment.

[0065] More preferably, a heat insulation layer is provided on the backlight side of the solid particle heat absorber, and a heat insulation layer is provided on the non-heat absorption section on the light-facing side of the solid particle heat absorber. As Figure 1 shown, a part of the heat insulation layer is located on the light-facing side of the heat absorber, so that only the quartz tube area receiving concentrated solar irradiation is exposed to the air; specifically, a first heat insulation layer 5a is provided on the light-facing side of the first valve 4 and the first guide pipe 6, a second heat insulation layer 5b is provided on the light-facing side of the first funnel 11, the second valve 12 and the second guide pipe 13, a third heat insulation layer 5c is provided on the light-facing side of the tapered section 16 and the third guide pipe 17, a fourth heat insulation layer 5d is provided on the light-facing side of the second funnel 21 and the third valve 22, and a fifth heat insulation layer 5e is provided on the entire backlight side of the heat absorber, achieving the effect of reducing heat loss.

[0066] More preferably, a first funnel 11 is provided between the first low-speed heat absorption section and the high-speed heat absorption section, and a second funnel 21 is provided between the second low-speed heat absorption section and the high-temperature particle storage tank. The funnels and valves can regulate the flow rate of the solid particles when they accumulate and fall. The function of the funnel is to realize the accumulation and falling inside the pipe, and the function of the valve is to adjust the speed of the accumulation and falling.

[0067] Most of the components in this embodiment are fixed by flanges. Specifically, refer to Figure 1, the first diversion pipe 6 is fixed to the outer pipe 8 of the heat absorption sleeve through the first flange 7a, the first funnel 11 is fixed to the outer pipe 8 of the heat absorption sleeve through the second flange 7b, the third diversion pipe 17 is fixed to the second outer pipe 18 of the second low-speed heat absorption section through the third flange 7c, the second funnel 21 is fixed to the second outer pipe 18 through the fourth flange 7d, the heat absorption pipes 14 in the high-speed heat absorption section are fixed to each other through the fifth flange 7e, the second diversion pipe is fixed to the heat absorption pipe 14 through the sixth flange 7f, and the tapered section 16 is fixed to the heat absorption pipe 14 through the seventh flange 7g. All flanges are covered by a heat insulation layer and do not directly receive concentrated solar irradiation. Except for the fifth flange, other flanges are made of metal, and the fifth flange 7e is made of quartz and receives concentrated solar irradiation.

[0068] See Figure 1 , the first diversion pipe 6 is located above the first heat absorption sleeve of the first low-speed heat absorption section and is fixed by the first flange 7a, and the first valve 4 is located above the first diversion pipe 6; the first funnel 11 (conical funnel) is located below the first heat absorption sleeve of the first low-speed heat absorption section and is fixed by the second flange 7b, and the second valve 12 is located below the first funnel 11. The fixation of the first heat absorption sleeve in the first low-speed heat absorption section is achieved according to the positional relationship between the first diversion pipe 6 and the first funnel 11.

[0069] The second diversion pipe 13 is located above the heat absorption pipe group and is fixed by the sixth flange 7f; the tapered section 16 is located below the heat absorption pipe group and is fixed by the seventh flange 7g. The fixation of the heat absorption pipe group is achieved according to the positional relationship between the second diversion pipe 13 and the tapered section 16. The heat absorption pipe group is composed of multiple heat absorption pipes connected in series. The end of each quartz pipe in the heat absorption pipe group is welded with a fifth flange 7e, and the flow guiding member 15 is inserted into each heat absorption pipe in the heat absorption pipe group and fixed through the fixing hole 15e. The flow guiding member is fixedly connected to the fifth flange 7e welded to the end of the adjacent quartz pipe through the fixing hole 15e by bolts.

[0070] The third diversion pipe 17 is located above the second heat absorption sleeve of the second low-speed heat absorption section and is fixed by the third flange 7c; the second funnel 21 is located below the second heat absorption sleeve of the second low-speed heat absorption section and is fixed by the fourth flange 7d, and the fourth valve 22 is located below the second funnel 21. The fixation of the second quartz sleeve in the second low-speed heat absorption section is achieved according to the positional relationship between the third diversion pipe 17 and the second funnel 21.

[0071] To ensure the stable flow of particles during the operation of the heat absorber, the following two conditions need to be met:

[0072] (1) When the second valve 12 is fully open, the particle flow rate in the low-speed heat absorption section and the maximum flow rate when all discharge holes 15c in the high-speed heat absorption section discharge materials stably meet the following: ≤ Since no valve is provided in the high-speed heat absorption section for flow regulation, the condition can be met to achieve the same flow rate in the low-speed heat absorption section and the high-speed heat absorption section during actual operation. The aperture and number of the discharge holes and the opening degree of the second valve can be designed to meet this condition;

[0073] (2) The second valve 12 and the third valve 22 are synchronously regulated and the opening degrees are close to ensure the same particle flow rate in the low-speed heat absorption section and the second low-speed heat absorption section, so as to ensure the same particle flow rate in the three heat absorption sections, thus avoiding the instability of particle flow in the heat absorber.

[0074] The working process of the solid particle heat absorber of the present invention is as follows:

[0075] Before operation, open the first valve 4 and close the second valve 12 and the third valve 22. When the solid particles 3 in the low-temperature particle storage tank 2 flow into the first diversion pipe 6 and fill the semi-circular light-facing side gap of the heat absorption sleeve in the first low-speed heat absorption section, open the second valve 12. The solid particles 3 flow from the first funnel 11 into the second diversion pipe 13 and achieve an array-type particle beam free fall in each heat absorption pipe of the heat absorption pipe group in the high-speed heat absorption section. When the solid particles 3 flow out of the high-speed heat absorption section from the tapered section 16 and enter the third diversion pipe 17 in the second low-speed heat absorption section and fill the semi-circular light-facing side gap of the heat absorption sleeve in the second low-speed heat absorption section, open the third valve 22 and maintain the opening degrees of the second valve 12 and the third valve 22 to be close to each other. The solid particles 3 flow into the high-temperature particle storage tank 23, and then the particle flow mode of "moving bed-free fall-moving bed" in the heat absorber is established. During operation, synchronously adjust the opening degrees of the second valve 2 and the third valve 22 according to the input concentrated solar energy flow. The solid particles 3 in the three heat absorption sections are heated by the concentrated solar energy. Open the fourth valve 24 and start the elevator 1. The solid particles 3 in the high-temperature particle storage tank 23 flow into the bottom of the elevator 1 and are lifted to the top of the elevator 1 and then flow into the low-temperature particle storage tank 2 to achieve cyclic heating until the average temperature of the solid particles 3 in the high-temperature particle storage tank 23 reaches the ideal high-temperature state.

[0076] Those skilled in the art can easily understand that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

[0077] The parts not elaborated in detail in the specification of the present invention belong to the well-known technology in the art. The above embodiments are provided only for the purpose of describing the present invention and are not intended to limit the scope of the present invention. The scope of the present invention is defined by the appended claims. All equivalent replacements and modifications made without departing from the spirit and principle of the present invention should be covered within the scope of the present invention.

Claims

1. A solid particle heat absorber, characterized in that: The solid particle heat absorber comprises a low-speed heat absorption section and a high-speed heat absorption section; the low-speed heat absorption section is connected to the high-speed heat absorption section; wherein the average speed of solid particles passing through the low-speed heat absorption section is less than the average speed of solid particles passing through the high-speed heat absorption section; Among them, the concentrated solar flux density q is 1 / 3q max ≤q≤q max The area is the high-speed heat absorption section, and the concentrated solar flux density q is 0≤q in ≤1 / 3q max The area is the low-speed heat absorption section, where q max is the peak energy flux density.

2. The solid particle heat absorber according to claim 1, characterized in that: The average speed of the solid particles passing through the low-speed heat absorption section is no more than 0.15 m / s, and the average speed of the solid particles passing through the high-speed heat absorption section is no more than 2 m / s.

3. The solid particle heat absorber according to claim 1, characterized in that: When the solid particle heat absorber is applied to an annular heliostat field, there are two low-speed heat absorption sections and one high-speed heat absorption section, and the two low-speed heat absorption sections are respectively located at the upper end and the lower end of the high-speed heat absorption section.

4. The solid particle heat absorber according to claim 1, characterized in that: The low-speed heat absorption section includes a heat absorption sleeve, which includes an outer tube and an inner tube. Both ends of the inner tube are opened and closed, and the inner tube is fixedly embedded in the outer tube. The gap between the outer tube and the inner tube forms a channel for the solid particles to pass through.

5. The solid particle heat absorber according to claim 4, characterized in that: The average diameter of solid particles d p Satisfy: 6≤δ / d p ≤12, wherein δ is the gap thickness between the outer tube and the inner tube.

6. The solid particle heat absorber according to claim 4, characterized in that: A filling layer is arranged on the light-proof side of the gap between the outer tube and the inner tube.

7. The solid particle heat absorber according to claim 4, characterized in that: The low-speed heat absorption section includes a plurality of heat absorption sleeves, and the plurality of heat absorption sleeves are arranged in an annular manner; And / or, the inner tube and the outer tube are made of quartz.

8. The solid particle heat absorber according to any one of claims 1 to 7, characterized in that: The high-speed heat absorption section includes a heat absorption tube for the solid particles to pass through.

9. The solid particle heat absorber according to claim 8, characterized in that: The heat absorbing tube of the high-speed heat absorbing section is a heat absorbing tube group composed of a plurality of heat absorbing tubes, the plurality of heat absorbing tubes are connected in series, a buffer plate is arranged between two adjacent heat absorbing tubes, and a plurality of through holes are arranged on the buffer plate.

10. The solid particle heat absorber according to claim 8, characterized in that: A flow guide component is arranged in the heat absorption tube of the heat absorption tube group, and the flow guide component includes a horizontal plate and a vertical plate. The vertical plate is vertically fixed on the horizontal plate, and the vertical plate divides the horizontal plate into a light-facing side horizontal plate and a backlight side horizontal plate. A discharge hole is arranged on the light-facing side horizontal plate.

11. The solid particle heat absorber according to claim 10, characterized in that: A flow guiding structure is also arranged on the light-facing side horizontal plate; the flow guiding structure is a plurality of protruding parts protruding from the horizontal plate.

12. The solid particle heat absorber according to claim 10, characterized in that: The horizontal plate on the light-facing side is provided with a discharge hole array formed by a plurality of rows of discharge holes, and the horizontal plate on the light-facing side is provided with a flow-guiding structure array formed by a plurality of rows of flow-guiding structure holes; the discharge holes and the flow-guiding structures are arranged at intervals.

13. The solid particle heat absorber according to claim 12, characterized in that: The high-speed heat absorption section includes a plurality of heat absorption tubes, and the plurality of heat absorption tubes are arranged in a ring shape; And / or, the heat absorption tube is made of quartz, and the flow guide component is made of ceramic.

14. The solid particle heat absorber according to claim 13, characterized in that: The solid particle heat absorber also includes a hoist, a low-temperature particle storage tank, a first guide pipe, a second guide pipe, a third guide pipe and a high-temperature particle storage tank; the low-temperature particle storage tank is connected to the first low-speed heat absorption section through the first guide pipe, the first low-speed heat absorption section is connected to the high-speed heat absorption section through the second guide pipe, the high-speed heat absorption section is connected to the second low-speed heat absorption section through the third guide pipe, and the second low-speed heat absorption section is connected to the high-temperature particle storage tank.

15. The solid particle heat absorber according to claim 14, characterized in that: A first valve is provided between the low-temperature particle storage tank and the first low-speed heat absorption section, a second valve is provided between the first low-speed heat absorption section and the high-speed heat absorption section, and a third valve is provided between the second low-speed heat absorption section and the high-temperature particle storage tank; and / or, a tapering section is provided between the high-speed heat absorption section and the second low-speed heat absorption section; And / or, a first funnel and a second funnel are respectively provided at the bottom of the first low-speed heat absorption section and the second low-speed heat absorption section.

16. The solid particle heat absorber according to claim 13, characterized in that: A heat-insulating layer is arranged on the backlight side of the solid particle heat absorber, and a heat-insulating layer is arranged on the non-heat-absorbing section on the light-facing side of the solid particle heat absorber.

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