阅读说明：本技术 一种塔式太阳能电站发电用逆流式高温粒子吸热器 (Counter-flow type high-temperature particle heat absorber for power generation of tower-type solar power station ) 是由 孔艳强 江凯军 张强 杨立军 杜小泽 杨勇平 于 2019-04-17 设计创作，主要内容包括：本发明公开了属于太阳能热发电领域的一种塔式太阳能电站发电用逆流式高温粒子吸热器,吸热器顶部装有粒子储料槽(1),颗粒(3)自上而下沿吸热器(2)流动。吸热器底部有布风室(4),颗粒从布风室侧面流出,空气自下而上流动,从顶部空气出流段(12)流出。吸热器气固体系逆向流动,颗粒无序碰撞,传热系数大、混合度高。通过控制气体流量调节颗粒下降速度和有效停留时间。此外,空气自下而上流动过程先吸热后对颗粒放热,可以减少流出系统的能量损失。本发明一种塔式太阳能电站发电用逆流式高温粒子吸热器具有操控性强、壁面与颗粒的传热系数高、热损失小的特点,展现了良好的应用前景。(The invention discloses a counter-flow high-temperature particle heat absorber for power generation of a tower-type solar power station, belonging to the field of solar thermal power generation, wherein a particle storage tank (1) is arranged at the top of the heat absorber, and particles (3) flow along the heat absorber (2) from top to bottom. An air distribution chamber (4) is arranged at the bottom of the heat absorber, particles flow out from the side of the air distribution chamber, air flows from bottom to top and flows out from a top air outflow section (12). The gas-solid system of the heat absorber flows reversely, particles collide disorderly, the heat transfer coefficient is large, and the mixing degree is high. The particle descending speed and the effective residence time are adjusted by controlling the gas flow. In addition, the air absorbs heat firstly and then releases heat to the particles in the process of flowing from bottom to top, so that the energy loss of the flowing-out system can be reduced. The counter-flow high-temperature particle heat absorber for power generation of the tower-type solar power station has the characteristics of strong controllability, high heat transfer coefficient between the wall surface and the particles and small heat loss, and shows good application prospect.)

1. The counter-flow high-temperature particle heat absorber for power generation of the tower-type solar power station is characterized by comprising a particle tank (1), a heat absorber pipe (2), solid heat absorbing particles (3), an air distribution chamber (4), a particle outlet section (5), an air outflow section (12) and a connecting pipeline valve; solid particles enter the particle tank (1) and flow from top to bottom, and heated high-temperature particles flow out of the heat absorber outlet section (5) and enter the hot particle storage tank; air enters the bottom air distribution chamber (4) through an air inlet header pipe (7), then enters the heat absorber pipe (2), forms reverse flow with particles from bottom to top, and then is discharged from the top outflow section (12) of the heat absorber.

2. The counter-flow high-temperature particle heat absorber for the power generation of the tower-type solar power station as claimed in claim 1, characterized in that the heat absorber tube (2) is made of alloy high-temperature resistant metal material; during the falling process of the particles, the solid phase volume fraction is 25-55%, the particle diameter is mum or mm magnitude, and the particles can resist the high temperature of more than 1000 ℃; to reduce particle-to-particle and particle-to-wall wear, the particles are approximately spherical in shape.

3. The counter-flow high-temperature particle heat absorber for the power generation of the tower-type solar power station as claimed in claim 1, wherein the air distribution chamber (4) is positioned at the center of the bottom of the heat absorber pipe, and the ratio of the projection area of the air distribution chamber to the cross-sectional area of the heat absorber pipe is 1/4-3/4, which is determined according to particle properties and operation parameters; in order to ensure uniform air distribution, an arc-shaped air distribution plate or a trapezoid air distribution plate is adopted, openings are uniformly formed in the air distribution plate, and the opening direction is the normal direction of the air distribution plate; the particle descending speed and the particle concentration are controlled by adjusting the air distribution; the top air outlet is a mesh screen structure that allows air to flow through the mesh openings, which are sized to limit the passage of particles.

4. The counter-flow high-temperature particle heat absorber for power generation of the tower-type solar power station as claimed in claim 1, wherein the heat absorber tube bundles are annularly arranged around the top of the tower or arranged in the cavity-type heat absorber in a wall-type structure, and the particle grooves (1) are in an annular or linear structure according to different arrangement modes of the heat absorber tube bundles.

5. The counter-flow high-temperature particle heat absorber for power generation of the tower-type solar power station as claimed in claim 1, wherein the particles and air are subjected to a zone control method; the air distribution pipelines (6) of the heat absorber are communicated with the air distribution header (8) of each section, and each air distribution pipeline (6) is provided with an air gauge and a throttle valve, so that air distribution control is facilitated; the outlet section (5) of the heat absorber is communicated with the particle storage tank (9) of each section of the outlet particles.

Technical Field

The invention belongs to the field of solar thermal power generation, and particularly relates to a counter-flow high-temperature particle heat absorber for power generation of a tower-type solar power station.

Background

Solar energy is used as a clean and efficient renewable energy source, and is widely adopted in regions with rich solar energy resources in China in recent years. The tower type solar thermal power generation technology represents the development trend of the focusing type solar thermal power generation technology due to the advantages of high heat collection efficiency, high heat-power conversion efficiency, high system comprehensive efficiency, large cost reduction space, suitability for large-scale application and the like. The tower type solar power station mainly comprises a heliostat field, a heat absorber, a heat storage system and a steam turbine generator unit, wherein the heat absorber system is used as a key component for realizing the conversion of solar energy to heat energy, and the guarantee of high-performance safe operation is an important ring for the research and application of solar thermal power generation.

The traditional solar heat absorber mostly adopts binary nitrate (NaNO3-KNO3, also called solar salt) as a heat transfer medium, when the working temperature exceeds 550 ℃, the chemical inertness of the solar salt is weakened, the metal pipe wall is easy to decompose and corrode, and when the temperature is lower than 250 ℃, the molten salt is solidified, the safe operation of the system is influenced, and a heat tracing system needs to be started. In order to improve the solar thermal power generation efficiency and reduce the power generation cost, the research on the structure of a novel high-temperature solar heat absorber is particularly important. In recent years, scholars at home and abroad successively put forward various high-temperature heat absorber structures: the solid particle packed bed type air heat absorber proposed by the electrical engineering of the Chinese academy of sciences aims at heating high-temperature air, but has the problem of energy storage; the horizontal particle high-temperature particle heat absorber researched by Beijing university of chemical industry has a structure of a long and narrow rectangular channel, so that the particles are difficult to realize a tower type heat absorber structure and are often accompanied with the problem of thermal stress; french researchers have proposed the particle heat absorber of the bubble fluidized bed of the suspension rising type, the particle is suspended and risen under the function of air fluidization, but the air lock phenomenon appears very easily in the course of rising, thus stop up the particle to rise; the falling particle curtain type heat absorber invented by the American Sangya laboratory can directly receive solar radiation, the radiation loss is small, but the particles fall down under the action of gravity in an accelerated mode, the sufficient heat absorption time of the particles is difficult to guarantee, and therefore the particle outlet temperature is low. In summary, although the existing solar heat absorbers have various advantages, the defects inherent in the operation process always occur.

On the basis of summarizing the previous research, the invention provides a novel counter-flow high-temperature particle heat absorber for power generation of a tower-type solar power station, which has the functions of heat collection and heat storage, overcomes the defect of short solar energy absorption method by fused salt, and improves the heat collection temperature and the subsequent heat exchange efficiency. The invention has the following beneficial effects: 1. the residence time of the particles in the heat absorber is increased, and higher particle outlet temperature is obtained; 2. the gas and solid flow reversely, so that the collision frequency between particles and between the particles and the wall surface is increased, and the heat transfer performance between the particles and the pipe wall is improved; 3. the solar energy non-uniform radiation energy flow easily enables the temperature of the pipe wall to be uniformly distributed, and the local overtemperature phenomenon often occurs. The heat absorber structure ensures that the particle mixing degree in the tube is higher, and effectively relieves the local overtemperature of the tube wall caused by non-uniform radiation energy flow; 4. the particle descending speed is controlled by the air distribution amount, and the adjustment is flexible; 5. the gas phase and the solid phase in the heat absorber flow reversely, the air temperature is increased and then reduced, the temperature difference between the air inlet and the air outlet is small, and the energy loss of the heat absorber is reduced.

Disclosure of Invention

A counter-flow high-temperature particle heat absorber for power generation of a tower-type solar power station is characterized by comprising a particle tank 1, a heat absorber pipe 2, solid heat absorbing particles 3, an air distribution chamber 4, a heat absorber outlet section 5 and a connected pipeline valve. The solid particles enter from the particle tank 1 and flow from top to bottom, and the heated high-temperature particles flow out from the heat absorber outlet section 5 and enter the hot particle storage tank. Air enters the bottom air distribution chamber 4 through an air inlet header pipe 7, then enters the bottom air distribution chamber and flows reversely with particles from bottom to top, and then is discharged from a top outflow section 12 of the heat absorber.

The counter-flow high-temperature particle heat absorber for power generation of the tower-type solar power station is characterized in that a heat absorber pipe 2 is made of an alloy high-temperature-resistant metal material. In the falling process of the particles, the solid phase volume fraction is 25-55%, and the particle diameter is high temperature resistant particles of mu m or mm grade; the particles are shaped as near spherical particles, reducing particle and component wear.

The counter-flow high-temperature particle heat absorber for power generation of the tower-type solar power station is characterized in that the air distribution chamber 4 is located at the center of the bottom of the heat absorber pipe, and the ratio of the projection area of the air distribution chamber to the cross-sectional area of the heat absorber pipe is 1/4-3/4, which is determined according to particle properties and operation parameters. In order to ensure uniform air distribution, an arc-shaped air distribution plate or a trapezoid air distribution plate is adopted, openings are uniformly formed in the air distribution plate, and the opening direction is the normal direction of the air distribution plate; the particle descending speed is adjusted by the air distribution amount; the top air outlet is a mesh screen structure that allows air to flow through the mesh openings, which are sized to limit the passage of particles.

The counter-flow high-temperature particle heat absorber for power generation of the tower-type solar power station is characterized in that a heat absorber tube bundle is annularly arranged around the top of the tower or arranged inside a cavity-type heat absorber in a wall-type structure, and a particle groove 1 is of an annular or linear structure according to different arrangement modes of the heat absorber tube bundle.

The counter-flow high-temperature particle heat absorber for power generation of the tower-type solar power station is characterized in that the particles and air adopt a partition control method. The air distribution pipelines 6 of the heat absorber are communicated with the air distribution header 8 of each section, and each air distribution pipeline 6 is provided with an air gauge and a throttle valve, so that air distribution control is facilitated. The outlet section 5 of the heat absorber is communicated with the particle storage tank 9 of each section of the outlet particles.

Drawings

Fig. 1 is a working principle diagram of a single counter-flow high-temperature particle heat absorber.

FIG. 2 is a schematic view of a heat sink bundle arrangement wherein a is external and b is a cavity.

Fig. 3 is a two-dimensional schematic view of the air distribution chamber device, wherein a is an arc-shaped air distribution plate structure and b is a trapezoid air distribution plate structure.

Fig. 4 is a gas-solid flow distribution diagram of the external heat absorber, wherein a is an air distribution mode and b is a particle flow.

Fig. 5 is a gas-solid flow distribution diagram of a cavity type heat absorber, wherein a is an air distribution mode and b is a particle flow.

Detailed Description

The invention provides a counter-flow high-temperature particle heat absorber for power generation of a tower-type solar power station, which is described below with reference to the accompanying drawings.

Fig. 1 shows a counter-flow high-temperature particle heat absorber for power generation of a tower-type solar power station, which comprises a particle tank 1, a heat absorber pipe 2, solid heat absorbing particles 3, an air distribution chamber 4, a particle outlet section 5, an air outlet section 12, connecting pipelines and valves. The heat absorber is arranged at the top of the heat absorption tower and has two structural forms, wherein one structural form is that the heat absorber pipe bundle arranged outside the tower top is shown in figure 2a, and the other structural form is that the heat absorber pipe bundle arranged in the cavity type at the tower top is shown in figure 2 b. In the operation process, the solid particles 3 enter the heat absorber particle groove 1 from the low-temperature particle storage tank, fall along the heat absorber pipe 2 under the action of gravity, and absorb the heat energy transferred to the metal pipe wall by solar energy. The bottom of the heat absorber is uniformly distributed with air, the air is sent into an air distribution chamber 4 through an air supply system, wherein the air distribution plate is of an arc structure or a trapezoid structure, and the air outlet is in the plane normal direction of the air distribution plate, as shown in fig. 3. Fluidizing air enters the absorber tubes 2 from the air distribution chamber 4 and flows in a reverse direction to the descending solid particles 3, so that the solid particles slowly and randomly fall, the particles are discharged into the particle storage tank 9 from the absorber outlet section 5, and air is discharged into the atmosphere from the top outlet section 12. Due to the structural arrangement of the air distribution chamber 4, the section of the outlet section of the heat absorber is narrowed, the flow resistance of particles is increased, and the retention time of the particles in the tube is further delayed. The air rises in the form of bubbles and is finally discharged from the top of the absorber. In the process of gas-solid two-phase reverse flow, the solid particles 3 can obtain higher outlet particle temperature and heat absorber efficiency. The temperature difference between the air inlet and the air outlet is small, and the energy loss of the heat absorber flowing out is reduced. Solid particles and fluidized air adopt a zone adjustment mode, fig. 4 and 5 are gas-solid flow charts of an external heat absorber and a cavity type heat absorber respectively, wherein a symbol (r) -ninthly schematically shows zone identification. The gas-solid flow is illustrated by taking the external heat absorber bundle structure of fig. 4 as an example, wherein fig. 4a is an air flow diagram and fig. 4b is a solid flow diagram. Air sequentially enters an air inlet header pipe 7, an air distribution header 8, a heat absorption pipe air inlet pipeline 6 and an air distribution chamber 4. A throttle valve 11 is arranged in the air inlet pipeline 6 of the heat absorption pipe to control the air flow entering the air distribution chamber 4. The air in the air distribution chamber 4 enters the absorber tube 2 along the air distribution plate holes, thereby fluidizing the solid particles 3 in the tube, and finally is discharged from the outlet section 12 at the top of the absorber tube. The solid particles 3 enter a heat absorber pipe 2, a heat absorber outlet section 5 and an outlet particle storage tank 9 from a particle tank 1 in sequence, and finally are collected in a high-temperature particle storage tank 10 to finish particle circulation.