Heat collection and heat preservation structure and heat collection and heat preservation device for fused salt tower of photo-thermal power station

Abstract

The invention discloses a heat collection and heat preservation structure and heat collection and heat preservation device for a fused salt tower of a photo-thermal power station, and the heat collection and heat preservation structure is a columnar hollow structure and sequentially comprises a high-temperature-resistant glass layer, a transparent aerogel layer and a heat absorption surface layer from outside to inside; solar radiation passes through the high-temperature-resistant glass layer and the transparent aerogel layer for heat preservation, and heat is generated and gathered in the heat absorption surface layer. The tower-type photo-thermal power station can spontaneously achieve heat preservation and heat collection, and effective utilization of solar radiation by the tower-type photo-thermal power station is improved.

Description

Technical Field

[0001] The present invention relates to the field of renewable energy power generation, and in particular to a heat collecting and heat insulating structure and a heat collecting and heat insulating device for a molten salt tower of a solar thermal power station. Background Art

[0002] Tower-type solar thermal power generation systems are expected to become a widely promoted solar power generation technology due to their large capacity, high-temperature heat storage capacity and stable power output. In this system, the molten salt in the high-temperature absorber exchanges heat with water to produce high-temperature and high-pressure steam, which drives the steam turbine to generate electricity. There are two main types of molten salt absorbers: exposed tube type and cavity type. Among them, the exposed tube type has a simple structure and can receive solar radiation within a range of 360°. It is suitable for large-scale mirror field layout and is currently the most widely used form of absorber. However, the energy loss caused by the reflection, radiation and convection heat dissipation generated by the exposed tube type is large, resulting in the inability to continue to increase the absorber temperature, thereby significantly reducing the thermal efficiency of the absorber tower.

[0003] In order to reduce heat loss, improve the thermal efficiency of the heat absorption tower, and maintain the temperature of the heat storage medium for the long-term stable operation of the internal equipment, shells and pipelines, it is necessary to adopt a reasonable insulation method for the heat absorption tower. Traditional insulation materials have good insulation effects, but due to their opacity, they cannot achieve the function of heat collection. The inner wall of the existing vacuum insulation structure is coated with a high-temperature resistant selective absorption coating, but the absorption layer cannot significantly improve the heat collection and heat storage effect, which is not conducive to increasing the working temperature of the heat absorber. In summary, the existing products and design solutions cannot meet the dual needs of insulation and heat collection at the same time. Therefore, it is urgent to develop innovative solutions that can take into account both insulation and heat collection in view of the defects such as energy loss of the exposed tube heat absorber in the existing technology, and propose a heat collection and insulation structure and heat collection and insulation device for the molten salt tower of a solar thermal power station. Summary of the invention

[0004] The main purpose of the present invention is to provide a heat collection and insulation structure and a heat collection and insulation device for a molten salt tower in a solar thermal power station, which are used to spontaneously achieve heat preservation and heat collection.

[0005] The technical solution adopted by the present invention is: a heat collection and insulation structure for a molten salt tower in a solar thermal power station, wherein the heat collection and insulation structure is a columnar hollow structure, which comprises, from the outside to the inside, a high-temperature resistant glass layer, a transparent aerogel layer and a heat-absorbing surface layer; solar radiation passes through the high-temperature resistant glass layer and the transparent aerogel layer used for insulation, generates and accumulates heat in the heat-absorbing surface layer, and a heat absorber is also provided in the hollow part of the heat collection and insulation structure for absorbing the heat accumulated in the heat-absorbing surface layer.

[0006] According to the above technical solution, the high temperature resistant glass layer meets the requirement that it will not deform or break when the temperature is lower than the preset temperature T1, and the transmittance of sunlight is higher than the preset value A1.

[0007] According to the above technical solution, the transparent aerogel layer has spectral selectivity, and the weighted transmittance of solar radiation within a preset wavelength range exceeds a preset value A2. Further, the spectral selectivity is that the aerogel has different transmittances for solar radiation of different wavelengths.

[0008] According to the above technical solution, the transparent aerogel layer also includes an infrared sunscreen agent in its composition, which is used to reduce the infrared band transmittance of the transparent aerogel layer within a preset wavelength range so that it meets a value lower than a preset value A3. Furthermore, conventional silicon aerogels increase the transmittance of infrared light at high temperatures, but the addition of an infrared sunscreen agent in the present invention ensures that the transmittance of infrared light in the high temperature section is reduced without damaging the transmittance of ultraviolet and visible light.

[0009] According to the above technical solution, the thermal conductivity of the transparent aerogel layer is lower than the preset value A4. Furthermore, the transparent aerogel has a fine network structure and nano-scale particle size, and has a good thermal insulation effect. Preferably, the production process of the aerogel is to fill a tile-shaped aerogel block between the high temperature resistant glass and the heat absorber.

[0010] Furthermore, the manufacturing process of the transparent aerogel layer includes: selecting an organic or inorganic silicon source as a precursor material, an alcohol solution as a cosolvent, an alkaline solution as a catalyst, deionized water as a hydrolysis raw material, and nano-alumina as an infrared shading agent, mixing the above materials and stirring them fully; pouring the stirred solution into a mold, solidifying and forming, and obtaining a wet gel; soaking the wet gel in the cosolvent for a preset time to wash away the moisture in the gel; drying the wet gel to obtain aerogel particles or aerogel blocks. Preferably, using a continuous supercritical device to dry the wet gel can better meet the production capacity.

[0011] According to the above technical solution, the heat absorbing surface layer adopts a coating material with a tolerance temperature higher than a preset temperature T2, a solar emissivity lower than a preset value A5, and a solar absorptivity higher than a preset value A6.

[0012] Another aspect of the present invention provides a thermal collector and insulator for a molten salt tower of a solar thermal power station, the thermal collector and insulator comprising the above-mentioned thermal collector and insulation structure, a header and a support structure, wherein the header is arranged at the upper end of the thermal collector and insulation structure, and the support structure is arranged at the lower end of the thermal collector and insulation structure.

[0013] According to the above technical solution, the support structure includes a protective base, a base plate and a support frame;

[0014] The protective base is in contact with the substrate, and the support frame is composed of a plurality of support ribs, one end of each support rib is connected to the substrate.

[0015] According to the above technical solution, the heat absorbing surface layer is also connected to the hot air outlet and the cold air inlet; the cold air enters from the cold air inlet to reduce the temperature of the heat absorbing surface layer and is discharged from the hot air outlet.

[0016] According to the above technical solution, the hot air outlet and cold air inlet are respectively installed with temperature and pressure sensors for monitoring the heat absorbing surface layer, and the opening and closing of the hot air outlet and cold air inlet valves are controlled based on the monitoring data of the temperature and pressure sensors.

[0017] The beneficial effects produced by the present invention are:

[0018] 1. The present invention provides a heat collection and insulation structure and a heat collection and insulation device for a molten salt tower of a solar thermal power station, wherein the heat collection and insulation structure is designed based on transparent aerogel, can spontaneously achieve heat preservation and heat collection, and is particularly suitable for effectively absorbing solar radiation at low temperatures. Based on the composition of the heat collection and insulation structure and the heat collection and insulation device of the present invention, solar radiation passes through the high-temperature resistant glass layer and the transparent aerogel layer with heat insulation function, generates and accumulates heat on the heat absorption surface layer, and heats the header fixed on the upper end of the heat collection and insulation structure.

[0019] 2. Traditional thermal insulation materials used in the prior art, such as opaque expanded perlite, aerogel felt and other materials, cannot effectively achieve heat collection and light concentration, increasing the risk of solidification of molten salt and the problem of non-concentration of thermal stress in internal pipelines. The transparent aerogel used in the thermal insulation structure of the present invention has a high transmittance to solar radiation and can effectively concentrate light and heat. Because it has a fine network structure and nano-scale particle size, the thermal conductivity is extremely low, which can form a good thermal insulation effect.

[0020] 3. The thermal insulation materials used in the prior art need to be manually filled into the heat-collecting and heat-insulating structure when the solar radiation intensity is weak, and the control cost is relatively high. The thermal insulation and heat-collecting functions realized by the thermal insulation materials of the present invention are completely passive, do not rely on external control, and have relatively low control costs.

[0021] 4. The conventional silicon aerogel used in the thermal insulation structure of the prior art will increase the transmittance of infrared light under high temperature conditions. The present invention adds an infrared sunscreen to the aerogel, which can reduce the transmittance of infrared light at high temperatures without damaging the transmittance of ultraviolet and visible light, and effectively reduce the heat loss of the absorber at an operating temperature of 300-1000°C.

[0022] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 This is a schematic structural diagram of a heat collection and heat preservation structure for a molten salt tower in a solar thermal power station according to an embodiment of the present invention;

[0025] Figure 2 This is a schematic structural diagram of a heat collector and insulator for a molten salt tower in a solar thermal power station according to an embodiment of the present invention;

[0026] Figure 3 Another structural schematic diagram of a heat collector and heat insulator for a molten salt tower in a solar thermal power station according to an embodiment of the present invention;

[0027] Figure 4 This is a data diagram of the light transmittance of the transparent aerogel layer of an embodiment of the present invention at different solar radiation wavelengths.

[0028] Figure numerals: 1. collecting box; 2. heat collection and insulation structure; 201. high temperature resistant glass layer; 202. transparent aerogel layer; 203. heat absorption surface layer; 3. protective base; 4. substrate; 5. support frame; 6. cold air inlet; 7. hot air outlet. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with 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.

[0030] It should be noted that the illustrations provided in the embodiments of the present invention are only used to illustrate the basic concept of the present invention in a schematic manner. Therefore, the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout type may also be more complicated.

[0031] In the present invention, it is also necessary to explain that, if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, if the terms "first" and "second" appear, they are only used for description and distinction purposes, and cannot be understood as indicating or implying relative importance.

[0032] Example 1

[0033] This embodiment provides a heat collection and insulation structure for a molten salt tower in a solar thermal power station, such as Figure 1 As shown, the heat collection and heat preservation structure 2 is a columnar hollow structure, which comprises a high temperature resistant glass layer 201, a transparent aerogel layer 202 and a heat absorbing surface layer 203 from the outside to the inside.

[0034] Solar radiation passes through the high temperature resistant glass layer 201 and the transparent aerogel layer 202 for heat preservation, generates and accumulates heat on the heat absorbing surface layer 203 . A heat absorber is also provided in the hollow of the heat collecting and heat preserving structure 2 to absorb the heat accumulated by the heat absorbing surface layer 203 .

[0035] Furthermore, the high temperature resistant glass layer 201 does not deform or crack when the temperature is lower than the preset temperature of 800°C, and the transmittance to the sun is greater than or equal to the preset value of 95%. The transparent aerogel layer 202 has spectral selectivity, and the weighted transmittance of solar radiation in the wavelength range of 250-2500nm exceeds the preset value of 92%, and the maximum transmittance is 98%.

[0036] The transparent aerogel layer 202 includes an infrared sunscreen agent, which is used to reduce the transmittance of the transparent aerogel layer 202 in the infrared band between 2500nm-25000nm. Traditional silicon aerogels will increase the transmittance of infrared light under high temperature conditions, but the addition of infrared sunscreen agents in the present invention ensures that the transmittance of infrared light at high temperatures is reduced without damaging the transmittance of ultraviolet and visible light. That is, the transmittance in the infrared band between 2500nm-25000nm is extremely low, with a maximum transmittance of 20%, which effectively reduces the heat loss of the absorber at an operating temperature of 300-1000℃. The transmittance of the transparent aerogel layer 202 under solar radiation of different wavelengths is shown in the figure. Figure 4 shown.

[0037] The thermal conductivity of the transparent aerogel layer 202 is lower than the preset value of 0.02 W / m·K. The transparent aerogel has an extremely low thermal conductivity, as low as 0.02 W / m·K, due to its fine network structure and nano-scale particle size, and can form a good thermal insulation effect. In this embodiment, a tile-shaped aerogel block is filled between the high-temperature resistant glass and the heat absorber as a method for preparing the aerogel.

[0038] Furthermore, the preparation method of the transparent aerogel layer 202 includes: selecting an organic or inorganic silicon source as a precursor material, selecting an alcohol solution as a cosolvent, selecting an alkaline solution as a catalyst, selecting deionized water as a hydrolysis raw material, and nano-alumina as an infrared sunscreen, and mixing the above materials and stirring them fully; pouring the stirred solution into a mold, solidifying and forming, and obtaining a wet gel; soaking the wet gel in the cosolvent for a preset number of days to wash away the moisture in the gel; using a supercritical drying device to dry the wet gel to obtain aerogel particles or aerogel blocks. According to the above technical solution, the composition of the transparent aerogel layer includes an infrared sunscreen, which is used to reduce the transmittance of the transparent aerogel layer in the infrared band between 2500nm-25000nm.

[0039] The heat absorbing surface layer 203 is made of a coating material having a tolerance temperature higher than a preset temperature of 1500° C., an emissivity lower than a preset value of 0.1, and an absorptivity higher than a preset value of 0.9.

[0040] Example 2

[0041] This embodiment provides a heat collector and heat insulator for a molten salt tower in a solar thermal power station. The heat collector and heat insulator comprises the heat collector and heat insulator structure 2 described in Embodiment 1. Figure 2 As shown, it also includes a header 1, a supporting and protective base 3 and a supporting frame 5.

[0042] The heat collecting and heat preservation structure 2 heats the header 1 for collecting and distributing molten salt. The header 1 is fixed to the upper end of the heat collecting and heat preservation structure 2, and the supporting and protective base 3 is fixed to the lower end. The supporting and protective base 3 extends from an umbrella-shaped supporting frame 5.

[0043] The structural composition and material of the heat-collecting and heat-insulating structure 2 have been described in Example 1 and will not be repeated here.

[0044] Furthermore, if Figure 3 As shown, the heat absorbing surface layer 203 is also connected to the hot air outlet 7 and the cold air inlet 6 . The cold air enters from the cold air inlet 6 to reduce the temperature of the heat absorbing surface layer 203 and is discharged from the hot air outlet 7 .

[0045] The hot air outlet 7 and the cold air inlet 6 are respectively installed with temperature and pressure sensors for monitoring the heat absorbing surface layer 203, and the opening and closing of the valves of the hot air outlet 7 and the cold air inlet 6 are controlled based on the monitoring data of the temperature and pressure sensors.

[0046] Preferably, a base 4 is also provided on the supporting protection base 3 and the supporting frame 5 to share the force, expand the extension angle of the supporting frame, and further enhance the placement balance of the heat collecting and heat preservation device when in use.

[0047] In summary, the present invention proposes a heat collection and insulation structure and a heat collection and insulation device for a molten salt tower of a solar thermal power station, wherein the heat collection and insulation structure is designed with spectrally selective aerogel and can spontaneously achieve heat preservation and heat collection. The present invention improves the effective use of sunlight by tower-type solar thermal power stations and provides new support for the promotion of tower-type power generation.

[0048] It should be pointed out that, according to the needs of implementation, the various steps / components described in this application can be split into more steps / components, and two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0049] The order of execution of each step in the above embodiment does not mean the order of execution. The order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application.

[0050] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A heat collection and insulation structure for a molten salt tower in a solar thermal power station, characterized in that: The heat collection and heat preservation structure (2) is a columnar hollow structure, which comprises, from the outside to the inside, a high temperature resistant glass layer (201), a transparent aerogel layer (202) and a heat absorbing surface layer (203).

2. The heat collection and insulation structure for the molten salt tower of a solar thermal power station according to claim 1, characterized in that: The high temperature resistant glass layer (201) meets the requirement of not deforming or breaking at a temperature lower than a preset temperature T1, and having a transmittance to sunlight higher than a preset value A1.

3. The heat collection and insulation structure for the molten salt tower of a solar thermal power station according to claim 1, characterized in that: The transparent aerogel layer (202) has spectral selectivity, and the weighted transmittance of solar radiation within a preset wavelength range exceeds a preset value A2.

4. The heat collection and insulation structure for the molten salt tower of a solar thermal power station according to claim 3, characterized in that: The transparent aerogel layer (202) also includes an infrared shading agent in its components, which is used to reduce the infrared band transmittance of the transparent aerogel layer (202) within a preset wavelength range so that it satisfies a value lower than a preset value A3.

5. The heat collection and insulation structure for the molten salt tower of a solar thermal power station according to claim 1, characterized in that: The thermal conductivity of the transparent aerogel layer (202) is lower than a preset value A4.

6. The heat collection and insulation structure for the molten salt tower of a solar thermal power station according to claim 2, characterized in that: The heat absorbing surface layer (203) is made of a coating material having a tolerance temperature higher than a preset temperature T2, a solar emissivity lower than a preset value A5, and a solar absorptivity higher than a preset value A6.

7. A heat collector and insulator for a molten salt tower in a solar thermal power station, characterized in that: The thermal collector and insulator comprises a thermal collector and insulation structure for a molten salt tower in a solar thermal power station as described in any one of claims 1 to 6, a header (1) and a support structure, wherein the header (1) is arranged at the upper end of the thermal collector and insulation structure (2), and the support structure is arranged at the lower end of the thermal collector and insulation structure (2).

8. The heat collector and insulator for the molten salt tower of a solar thermal power station according to claim 7, characterized in that: The support structure comprises a protective base (3), a base plate (4) and a support frame (5); The protective base (3) is in contact with the base plate (4), and the support frame (5) is composed of a plurality of support ribs, one end of each support rib being connected to the base plate (4).

9. The heat collector and insulator for the molten salt tower of a solar thermal power station according to claim 8, characterized in that: The heat absorbing surface layer (203) is also connected to the hot air outlet (7) and the cold air inlet (6); the cold air enters from the cold air inlet (6) to reduce the temperature of the heat absorbing surface layer (203) and is discharged from the hot air outlet (7).

10. The heat collector and insulator for the molten salt tower of a solar thermal power station according to claim 9, characterized in that: The hot air outlet (7) and the cold air inlet (6) are respectively installed with temperature and pressure sensors for monitoring the heat absorbing surface layer (203), and the opening and closing of the hot air outlet (7) and the cold air inlet (6) valves are controlled based on the monitoring data of the temperature and pressure sensors.

Images