A type of particle heat absorber

Abstract

This invention discloses a particle heat absorber, comprising a top header and a fluidizing device arranged vertically. At least one sleeve connects the top header and the fluidizing device. Each sleeve includes an outer heat-absorbing tube and at least one inner tube disposed within the outer heat-absorbing tube. Both ends of the outer heat-absorbing tube are connected to the top header and the fluidizing device, respectively. Both ends of the inner tube are connected to the top header and the fluidizing device, respectively. The upper part of each outer heat-absorbing tube is connected to a gas distribution pipe. The lower end of each outer heat-absorbing tube is connected to a gas collecting pipe, which is connected to the fluidizing device. The fluidizing device is connected to a particle feeding device.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat absorber design, in particular to a granular heat absorber. BACKGROUND

[0002] The photo-thermal power generation technology uses solid particles as a photo-thermal heat storage medium, which is a breakthrough in improving power generation efficiency.

[0003] At present, the main solid particle heat absorbers include cavity free falling type, external quartz tube type and cavity fluidized bed type. One of the main difficulties is the control of particle flow rate in order to prolong the residence time of particles in the light receiving place. The problem of free falling type is that the particle flow rate cannot be controlled and the residence time is too short. The quartz tube type proposed by the Chinese Academy of Sciences can delay the falling of particles, but the main problem is that the particles wear the inner wall of the quartz tube, resulting in a decrease in the light transmittance of the quartz tube and a decrease in the absorption efficiency of the radiant energy by the quartz tube; in addition, the structural strength of the slender quartz tube is also difficult to guarantee. The heat absorber using the fluidized bed type, the light shines on the outer wall of the metal tube, and the particles flow in the metal tube for indirect heat absorption, which can well control the particle flow rate, but due to the low heat exchange coefficient between the particles and the metal tube wall, the heat absorption effect is not good, and the metal tube wall temperature is too high, which causes the performance of the metal material to decrease sharply under high temperature conditions; in addition, the back light surface and the light receiving surface of the metal tube are not uniformly heated, which leads to thermal stress damage and also limits the application of the fluidized bed metal tube. SUMMARY

[0004] In view of the above problems, the present application provides a granular heat absorber, which comprises a top header arranged above and below and a fluidization device, at least one sleeve is connected between the top header and the fluidization device; the sleeve comprises a heat absorbing outer tube and at least one inner tube arranged in the heat absorbing outer tube, both ends of the heat absorbing outer tube are connected with the top header and the fluidization device respectively, both ends of the inner tube are communicated with the top header and the fluidization device respectively; the upper part of the heat absorbing outer tube is communicated with a gas distribution pipe; the lower part of the heat absorbing outer tube is communicated with a gas collecting pipe, the gas collecting pipe is communicated with the fluidization device, and the fluidization device is connected with a particle feeder.

[0005] After being preheated by the regenerator, the gas flow enters between the outer tube and the inner tube through the gas distribution pipe, flows from top to bottom in the outer tube and absorbs solar radiation to heat up, and exchanges heat with the inner tube at the same time; the gas flow in the outer tube enters the fluidization device through the gas collecting pipe, drives the particles transported by the feeder into each inner tube, exchanges heat with the gas flow outside the tube through the inner tube, and then enters the top header after the heat exchange is completed, is separated by a gas-solid separator, and the separated high-temperature gas is sent back to the regenerator.

[0006] In some embodiments, the heat-absorbing outer tube is a light-transmitting quartz tube, and the inner tube is a metal tube.

[0007] In some embodiments, the aperture of the upper end of the heat-absorbing outer tube is larger than the aperture of the lower end.

[0008] In some embodiments, the aperture of the upper end of the inner tube is smaller than the aperture of the lower end.

[0009] In some embodiments, the sleeve is connected to the top header and the fluidization device through a sleeve bottom base.

[0010] The end of the outer tube is coaxially installed on the sleeve base through a first flange, and the sleeve base is fixed on the top header and the fluidization device; the inner tube is installed on the sleeve base through a second flange, and the sleeve base is provided with a through hole corresponding to each end of the inner tube, and the inner tube communicates with the inside of the top header and the fluidization device through the through hole.

[0011] In some embodiments, a plurality of sleeves are arranged between the top header and the bottom air chamber, and the plurality of sleeves are arranged side by side.

[0012] In some embodiments, a plurality of inner tubes are arranged in the heat-absorbing outer tube.

[0013] In some embodiments, the fluidization device comprises an air chamber and a distribution plate arranged in the air chamber, the gas collecting pipe communicates with the air chamber, and the outlet of the particulate feeding device is located above the distribution plate; after the gas forms fluidized air through the distribution plate, the particulate is carried into the inner tube.

[0014] In some embodiments, a regenerator and a gas-solid separator are further included, and the gas-solid separator is arranged between the regenerator and the top header.

[0015] The gas distribution pipe communicates with the regenerator, and the regenerator communicates with the top header through the gas-solid separator.

[0016] In some embodiments, the gas-solid separator is a cyclone separator, and the particulate feeding device adopts a screw feeder.

[0017] Compared with the prior art, the above technical scheme has the following advantages and positive effects:

[0018] 1. The particulate heat absorber provided by the application uses a sleeve structure, uses gas as an intermediate heat medium between the quartz tube and the metal tube, carries away the radiant energy by the gas, heats the metal tube while avoiding high temperature of the outer wall of the metal tube, avoids softening of the metal tube directly subjected to high temperature and strong radiation, and solves the problem of reduction of light transmission of the quartz tube directly contacting the particulate.

[0019] 2、The particle heat absorber provided by the present application solves the problem that the particles in the fluidized bed heat absorber only indirectly absorb heat through the tube wall, and thus the heat exchange coefficient is not high, and meanwhile retains the advantage of the fluidized bed in adjusting the particle flow rate; in addition, the forced convection heat exchange by the gas ensures that the metal outer wall is uniformly heated and avoids thermal stress damage.

[0020] 3、The particle heat absorber provided by the present application enhances the gas disturbance in the metal tube and the quartz tube respectively through the tapered structure of the metal tube and the quartz tube, and strengthens the heat exchange; the converging gas passage formed between the metal tube and the quartz tube is beneficial to the formation of the fluidization wind speed; and the particles in the metal tube can prolong the residence time when the temperature difference between the inside and the outside is large and the gas temperature is high, which is beneficial to sufficient heat exchange.

[0021] 4、The particle heat absorber provided by the present application puts several metal tubes into a single quartz tube, compared with the single quartz tube heat absorber, the quartz tube of the present application can be made thicker, the height-diameter ratio is reduced, the structural strength is more reliable, and the quartz tube can also be made longer, which is beneficial to large-scale application. At the same time, since the high-temperature metal tube itself will radiate heat to the outside, several metal tubes are arranged together, which can absorb part of the radiation and reduce heat loss. BRIEF DESCRIPTION OF DRAWINGS

[0022] The above and other features and advantages of the present application will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0023] Figure 1 FIG. 1 is a front view of a system architecture diagram of a particle heat absorber provided in Embodiment 1 of the present application;

[0024] Figure 2 FIG. 2 is a right view of a schematic diagram of a sectional view of the particle heat absorber provided in Embodiment 1 of the present application;

[0025] Figure 3 FIG. 3 is a schematic diagram of a structure of a sleeve tube in the present application. DETAILED DESCRIPTION

[0026] The present application will be described in greater detail by referring to the drawings, in which embodiments of the present application are shown. The present application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the application to those skilled in the art. In the drawings, the size and relative sizes of layers and regions can be exaggerated for clarity.

[0027] Reference Figures 1-3The application provides a particle heat absorber, which comprises a top header 8 and a fluidization device arranged in a top-bottom mode, at least one sleeve 14 is connected between the top header 8 and the fluidization device; the sleeve 14 comprises a heat absorbing outer tube 2 and at least one inner tube 3 arranged in the heat absorbing outer tube 2, two ends of the heat absorbing outer tube 2 are connected with the top header 8 and the fluidization device respectively, two ends of the inner tube 3 are communicated with the top header 8 and the fluidization device respectively, and the upper part of each heat absorbing outer tube 2 is communicated with a gas distribution pipe 1; the lower part of each heat absorbing outer tube 2 is communicated with a gas collecting pipe 4, the gas collecting pipe 4 is communicated with the fluidization device, and a particle feeding device 7 is connected to the fluidization device.

[0028] Further, the gas distribution pipe 1 is communicated with a regenerator 10, the regenerator 10 is communicated with the top header 8, and a gas-solid separator 9 is arranged between the regenerator 10 and the top header 8.

[0029] During operation, the gas flow is preheated by the regenerator 10, then enters between the heat absorbing outer tube 2 and the inner tube 3 through the gas distribution pipe 1, flows in the heat absorbing outer tube 2 from top to bottom and absorbs the radiation of the solar radiation to be heated up, and exchanges heat with the inner tube 2 at the same time; the gas flow in the heat absorbing outer tube 2 enters the fluidization device through the gas collecting pipe 4 to form fluidization wind, drives the particles fed by the particle feeding device 7 into the inner tube 3 through the bottom air chamber 5, exchanges heat with the gas flow outside the inner tube 3, and then enters the top header 8 after the heat exchange is completed, is separated by the gas-solid separator 7, and the separated high-temperature gas is sent back to the regenerator 10 for preheating and recycling.

[0030] The particle heat absorber provided by the application uses the sleeve structure, uses the gas as the intermediate heat medium between the heat absorbing outer tube and the inner tube, and carries away the radiation energy, thereby avoiding the problem that the inner tube is directly softened under the high temperature of strong radiation, and solving the problem of the decrease of the light transmittance caused by the direct contact with the particles. Further, the gas exchanges heat indirectly with the particles in the heat absorbing outer tube through the inner tube firstly, and then enters the inner tube as the fluidization gas to exchange heat directly with the particles, thereby solving the problem that the particles in the fluidized bed heat absorber only exchange heat indirectly with the inner tube through the tube wall, and the problem of the low heat exchange coefficient, and retaining the advantage that the fluidized bed can control and adjust the particle flow rate. In addition, the forced convection heat exchange mode through the intermediate medium-gas ensures that the outer wall of the inner tube is heated uniformly to avoid the damage caused by the thermal stress.

[0031] In the embodiment, the fluidization device comprises a bottom air chamber 5 and a wind distribution plate 6 arranged in the bottom air chamber 5; the lower end of the sleeve 14 is connected with the bottom air chamber 5, the inner tube 3 is communicated with the bottom air chamber 5 and the gas collecting pipe 4, and the wind distribution plate 6 is located between the inner tube 3 and the communication port of the bottom air chamber 5 and the gas collecting pipe 4. The wind distribution plate 6 is arranged to form the fluidization wind, and further, the outlet of the particle feeding device 7 is located between the wind distribution plate 6 and the inner tube inlet, that is, as shown in the figure, the outlet of the particle feeding device 7 is located in the inner tube 3. Figure 2As shown in Fig. 1, the outlet of the particle feeder 7 is located above the air distribution plate 6; the high-temperature gas from the gas collecting pipe 4 flows through the air distribution plate 6 to form fluidization air, and then carries the particles into the inner pipe 3.

[0032] In the embodiment, the heat-absorbing outer pipe 2 is preferably a light-transmitting quartz pipe to facilitate absorption of solar radiation; and the inner pipe 3 is preferably a metal pipe to facilitate better heat exchange. Of course, in other embodiments, the materials of the heat-absorbing outer pipe 2 and the inner pipe 3 can also be adjusted according to specific conditions, which are not limited herein.

[0033] In the embodiment, as shown in Fig. 1, the heat-absorbing outer pipe 2 is preferably provided with a plurality of inner pipes 3. Figure 1 As shown in Fig. 1, a plurality of sleeves 14 are arranged between the top header 8 and the bottom air chamber 5, and the plurality of sleeves 14 are arranged side by side to facilitate better absorption of solar radiation. The number of sleeves 14 is not limited herein and can be selected according to specific conditions.

[0034] Of course, in other embodiments, the arrangement of the plurality of sleeves 14 can also be adjusted according to specific conditions, for example, the plurality of sleeves 14 can be arranged in a ring shape, which is not limited herein and can be adjusted according to specific conditions.

[0035] In the embodiment, as shown in Fig. 1, the heat-absorbing outer pipe 2 is preferably provided with a plurality of inner pipes 3. Figure 3 In the embodiment, as shown in Fig. 1, the heat-absorbing outer pipe 2 is preferably provided with a plurality of inner pipes 3.

[0036] The specific number and arrangement of the inner pipes 3 can adopt the scheme shown in Fig. 1 or can be adjusted according to specific conditions, which are not limited herein. Figure 3

[0037] In the embodiment, preferably, the hole diameter of the end of the heat-absorbing outer pipe 2 connected to the top header 8 is larger than the hole diameter of the end of the heat-absorbing outer pipe 2 connected to the bottom air chamber 5, that is, the heat-absorbing outer pipe 2 is a conical pipe with a large upper end and a small lower end. The outer pipe with the above structure is adopted in the embodiment, and the contraction structure will facilitate the formation of a local negative pressure group of air flow, enhance air turbulence, and strengthen heat exchange; and because the gas passage between the pipes is gradually contracted, the gas flow rate is gradually increased, and a relatively high speed is obtained at the end, which facilitates fluidization of the particles.

[0038] Of course, in other embodiments, the heat-absorbing outer pipe 2 can also be a circular pipe with consistent upper and lower pipe diameters, and the cross section of the heat-absorbing outer pipe 2 can also be a polygonal shape, which is not limited herein and can be adjusted according to specific conditions.

[0039] ​In the embodiment, preferably, the inner tube 3 has a smaller diameter at the end connected to the top header 8 and a larger diameter at the end connected to the bottom plenum 5, i.e. the inner tube 3 is a tapered tube with a smaller diameter at the top and a larger diameter at the bottom. The inner tube with the above structure is adopted in the embodiment, and the contraction structure will facilitate the formation of a local negative pressure group of gas flow, enhance the gas turbulence, and strengthen the heat exchange. In addition, since the inner tube is a tapered tube with a larger diameter at the bottom and a smaller diameter at the top, the particle flow stays at the lower end of the tube for a longer time. Therefore, when the cold particles enter the inner tube from the bottom, they will make full use of the large temperature difference with the high-temperature gas outside the tube for indirect heat exchange.

[0040] Of course, in other embodiments, the inner tube 3 can also be a circular tube with a consistent diameter from top to bottom, and the cross section of the inner tube 3 can also be polygonal or other shapes, which are not limited here and can be adjusted according to specific conditions.

[0041] In the embodiment, the two ends of the sleeve pipe 14 are respectively installed on the top header 8 and the bottom plenum 5 through the sleeve pipe base 12.

[0042] Specifically, referring to Figure 3 , the end of the heat-absorbing outer pipe 2 is coaxially installed on the sleeve pipe base 12 through the first flange 11, and the sleeve pipe base 12 is fixedly arranged on the top header 8 and the bottom plenum 5. The inner tube 3 is installed on the sleeve pipe base 12 through the second flange 13, and the sleeve pipe base 12 is provided with through holes corresponding to the ends of the inner tubes 3. The inner tubes 3 are in communication with the inside of the top header 8 and the bottom plenum 5 through the through holes. In the embodiment, the connection mode of the inner and outer tubes is beneficial to ensure the stable connection and sealing effect of the connection. Of course, in other embodiments, the connection mode of the inner and outer tubes can be adjusted according to specific conditions, which is not limited here.

[0043] In the embodiment, preferably, the gas-solid separator 9 is a cyclone separator. Of course, in other embodiments, the separator can also be selected from other types of separators, which are not limited here.

[0044] In the embodiment, preferably, the particle feeding device 7 is a screw feeder. Of course, in other embodiments, the particle feeding device can also be selected from other types of separators, which are not limited here.

[0045] The working principle of the particle heat absorber provided by the present application will be further described as follows:

[0046] The low-temperature gas stream from the fan reaches about 550°C after preheating in the regenerator and enters each group of the jacketed pipes from the gas distribution pipe at the top of the absorber; the gas stream flows from top to bottom in the quartz pipe and absorbs the radiation of the sunlight to increase in temperature, while at the same time forced convection heat exchange occurs with the metal pipe; since the quartz pipe is a tapered pipe with a thick upper end and a thin lower end, and the metal pipe is a tapered pipe in the opposite direction, the channel for the gas stream formed by the two pipes gradually shrinks, so that the gas stream obtains a higher flow rate when it reaches the bottom end of the quartz pipe, and a higher speed at the end, which facilitates fluidization of the particles.

[0047] At this time, the gas stream, which has reached about 800°C after being heated, again enters the lower 4 headers from the bottom outlet of the quartz pipe, and then enters the bottom air chamber of the fluidized bed, while the low-temperature particles at 400°C continuously enter the air chamber from the screw feeder, the high-temperature gas stream fluidizes the low-temperature particles, and the gas-solid two-phase stream enters each metal pipe from the through hole of the jacketed pipe base; the low-temperature particles directly contact and exchange heat with the hot gas stream, while at the same time the particle flow also indirectly exchanges heat with the high-temperature gas outside the metal pipe through the pipe wall. Since the metal pipe is a tapered pipe with a thick lower end and a thin upper end, the particle flow stays at the lower end for a long time, and at this time the high-temperature air outside the pipe and the low-temperature particles inside the pipe have the largest temperature difference, so that when the low-temperature particles enter the metal pipe from the bottom, they will more fully exchange heat by indirect convection.

[0048] The 700°C gas-solid two-phase stream after heat exchange enters the top header 8 from the through hole at the top of the metal pipe, and then is separated by the cyclone separator; the separated high-temperature gas is transported to the regenerator for waste heat recovery, and exchanges heat with the cold gas from the fan, and the high-temperature gas is cooled to about 180°C, while the cold gas is preheated to 550°C and enters the jacketed pipe, completing the cycle.

[0049] Those skilled in the art will understand that the present application can be implemented in many other specific forms without departing from the spirit or scope thereof. Although embodiments of the present application have been described, it is understood that the present application should not be limited to these embodiments, and those skilled in the art can make changes and modifications within the spirit and scope of the present application as defined by the appended claims.

Claims

1. A particle heat sink, characterized by, The device comprises a top header and a fluidizing device arranged vertically, at least one jacket is connected between the top header and the fluidizing device; the jacket comprises a heat absorbing outer tube and at least one inner tube arranged in the heat absorbing outer tube, two ends of the heat absorbing outer tube are connected with the top header and the fluidizing device respectively, two ends of the inner tube are communicated with the top header and the fluidizing device respectively; the upper part of the heat absorbing outer tube is communicated with a gas distribution pipe; the lower part of the heat absorbing outer tube is communicated with a gas collecting pipe, the gas collecting pipe is communicated with the fluidizing device, and the fluidizing device is connected with a particle feeding device. The gas flow enters between the heat absorbing outer tube and the inner tube through the gas distribution pipe, the gas flow in the heat absorbing outer tube flows from top to bottom and absorbs solar radiation to increase temperature, and exchanges heat with the inner tube; the gas flow in the heat absorbing outer tube enters the fluidizing device through the gas collecting pipe to form fluidizing wind, and drives the particles fed by the particle feeding device to enter the inner tube, exchanges heat with the gas flow outside the inner tube, and enters the top header after heat exchange is completed. The aperture of the upper end of the heat absorbing outer tube is larger than that of the lower end; the aperture of the upper end of the inner tube is smaller than that of the lower end.

2. The particle heat sink of claim 1, wherein, The heat absorbing outer tube is a light-transmitting quartz tube, and the inner tube is a metal tube.

3. The particle heat sink of claim 1, wherein, The jacket is connected with the top header and the fluidizing device through a jacket bottom pipe seat; The end of the heat absorbing outer tube is coaxially installed on the jacket bottom seat through a first flange, the jacket bottom seat is fixed on the top header and the fluidizing device; the inner tube is installed on the jacket bottom seat through a second flange, and the jacket bottom seat is provided with a through hole corresponding to the end of each inner tube, and the inner tube is communicated with the inside of the top header and the fluidizing device through the through hole.

4. The particle heat sink of claim 1, wherein, The fluidizing device comprises a bottom air chamber, a plurality of jackets are arranged between the top header and the bottom air chamber, and the plurality of jackets are arranged side by side.

5. The particle heat sink of claim 1, wherein, A plurality of inner tubes are arranged in the heat absorbing outer tube.

6. The particle heat sink of claim 4, wherein, The fluidizing device further comprises a wind distribution plate arranged in the bottom air chamber, the gas collecting pipe is communicated with the bottom air chamber, and the outlet of the particle feeding device is located above the wind distribution plate; the gas flow forms the fluidizing wind after passing through the wind distribution plate, and carries the particles into the inner tube.

7. The particle heat sink of claim 1, wherein, A regenerator and a gas-solid separator are further included, and the gas-solid separator is arranged between the regenerator and the top header.

8. The particle heat sink of claim 7, wherein, The gas-solid separator is a cyclone separator, and the particle feeding device adopts a screw feeder.

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