High-temperature fused salt heat storage system

Abstract

The invention discloses a high-temperature fused salt heat storage system which comprises a high-temperature fused salt storage tank, the high-temperature fused salt storage tank is provided with a shell, and the shell comprises a first layer, a second layer, a third layer, a fourth layer and a fifth layer which are sequentially arranged from inside to outside in a sleeving mode. The first layer, the second layer, the third layer, the fourth layer and the fifth layer are one of a stainless steel part, a refractory part, a porous silicon carbide part, a phase change part and a carbon steel part, and the first layer forms an accommodating space for accommodating molten salt. According to the high-temperature fused salt heat storage system, the high-temperature fused salt storage tank has the excellent heat preservation performance under the high-temperature working condition, the heat dissipation loss of the high-temperature fused salt storage tank is effectively reduced, the overall bearing and external load resisting performance is enhanced, and the operation reliability of the high-temperature fused salt heat storage system is improved.

Description

Technical Field

[0001] This invention relates to the field of high-temperature thermal storage technology, and in particular to a high-temperature molten salt thermal storage system. Background Technology

[0002] Molten salt thermal energy storage technology is a highly efficient energy storage method that utilizes molten salt to store and release thermal energy. It is mainly used in fields such as solar thermal power generation, thermal power plant renovation, and industrial waste heat recovery, and has the advantages of high energy density and long-term energy storage.

[0003] Molten salt tanks are one of the core components of molten salt thermal storage systems. They generally include high-temperature molten salt tanks and low-temperature molten salt tanks. For high-temperature molten salt tanks, due to their large capacity and high temperature gradient, existing insulation structures are prone to insufficient heat loss control under extreme temperature differences and long-term operating conditions, resulting in a high heat loss rate and affecting the system's net output and economy. Summary of the Invention

[0004] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a high-temperature molten salt thermal storage system, which exhibits excellent thermal insulation performance under high-temperature operating conditions, effectively reduces heat loss from the high-temperature molten salt storage tank, enhances overall load-bearing capacity and resistance to external loads, and improves the operational reliability of the high-temperature molten salt thermal storage system.

[0005] According to an embodiment of the present invention, a high-temperature molten salt thermal storage system includes: a high-temperature molten salt storage tank, the high-temperature molten salt storage tank having an outer shell, the outer shell including a first layer, a second layer, a third layer, a fourth layer and a fifth layer sequentially arranged from the inside out, the first layer, the second layer, the third layer, the fourth layer and the fifth layer being one of stainless steel, refractory, porous silicon carbide, phase change, and carbon steel, the first layer forming a receiving space for accommodating the molten salt.

[0006] According to an embodiment of the present invention, the high-temperature molten salt thermal storage system comprises a high-temperature molten salt storage tank with an outer shell. The outer shell includes a first layer, a second layer, a third layer, a fourth layer, and a fifth layer sequentially arranged from the inside out. The first, second, third, fourth, and fifth layers are made of one of stainless steel, refractory, porous silicon carbide, phase change, and carbon steel. The first layer forms a space for containing molten salt, thereby enabling the high-temperature molten salt storage tank to have excellent heat preservation performance under high-temperature conditions, effectively reducing heat loss of the high-temperature molten salt storage tank, enhancing the overall load-bearing and external load resistance performance, and improving the operational reliability of the high-temperature molten salt thermal storage system.

[0007] In some embodiments of the present invention, the first layer is a stainless steel component, and a temperature detection device is provided on the outer wall surface of the first layer.

[0008] In some embodiments of the present invention, the temperature detection device includes a plurality of temperature sensors, which are arranged along the height and circumferential directions of the high-temperature molten salt storage tank.

[0009] In some embodiments of the present invention, the second layer is a refractory component, which is a heat-insulating brick; and / or, the third layer is a porous silicon carbide component, which has a porosity of 40%-60%; and / or, the fifth layer is a carbon steel component.

[0010] In some embodiments of the present invention, the fourth layer is a phase change element, the phase change point of which is 30°C-80°C; and / or, the phase change element is a phase change capsule; and / or, the phase change element is paraffin wax.

[0011] In some embodiments of the present invention, the invention further includes: a liquid distribution ring pipe, which is located at the bottom of the receiving space and is annular, and has a plurality of nozzles, which are spaced apart along the circumferential direction of the liquid distribution ring pipe; and a salt inlet pipe, one end of which extends into the receiving space and is connected to the liquid distribution ring pipe for conveying molten salt into the liquid distribution ring pipe.

[0012] In some embodiments of the present invention, the nozzle makes an acute angle with the horizontal direction and an acute angle with the vertical direction. Along the horizontal direction, the ends of the plurality of nozzles away from the liquid distribution ring pipe extend toward the same tangential direction in the circumferential direction of the liquid distribution ring pipe.

[0013] In some embodiments of the present invention, the angle between the nozzle and the horizontal direction is the same as the angle between the nozzle and the vertical direction; and / or, the angle between the nozzle and the horizontal direction is 15°-75°; and / or, the angle between the nozzle and the vertical direction is 15°-75°; and / or, a plurality of the nozzles are respectively disposed on both sides of the liquid distribution ring pipe along the vertical direction.

[0014] In some embodiments of the present invention, the invention further includes: an extension tube extending along the height direction of the receiving space, one end of the extension tube extending into the bottom of the receiving space, and the other end connected to a circulating salt tube and a salt outlet tube respectively, the other end of the circulating salt tube extending into the receiving space, the lowest point of the circulating salt tube in the receiving space being higher than the lowest point of the extension tube in the receiving space; an automatic circulating salt control valve connected in series between the extension tube and the circulating salt tube; an automatic salt outlet control valve connected in series on the salt outlet tube; and a molten salt pump connected to the extension tube for pumping molten salt from the receiving space into the extension tube and transporting it through the circulating salt tube or the salt outlet tube.

[0015] In some embodiments of the present invention, a control device is further included, which is communicatively connected to at least one of the circulating salt automatic control valve, the salt outlet automatic control valve, and the molten salt pump.

[0016] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of the structure of a high-temperature molten salt thermal storage system according to an embodiment of the present invention.

[0018] Figure label: 1. High-temperature molten salt storage tank; 2. First layer; 3. Temperature detection device; 4. Second layer; 5. Third layer; 6. Fourth layer; 7. Fifth layer; 8. Salt inlet pipe; 9. Salt outlet pipe; 10. Circulating salt pipe; 11. Molten salt pump; 12. Molten salt heater; 13. Liquid distribution ring pipe; 14. Nozzle; 15. Circulating salt automatic control valve; 16. Salt outlet automatic control valve; 17. Control device; 18. Extension pipe. Detailed Implementation

[0019] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0020] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0021] The high-temperature molten salt thermal storage system according to an embodiment of the present invention is described below with reference to the accompanying drawings.

[0022] like Figure 1 As shown, the high-temperature molten salt thermal storage system according to an embodiment of the present invention includes a high-temperature molten salt storage tank 1 with an outer shell. The outer shell includes a first layer 2, a second layer 4, a third layer 5, a fourth layer 6, and a fifth layer 7 arranged sequentially from the inside to the outside. The first layer 2, the second layer 4, the third layer 5, the fourth layer 6, and the fifth layer 7 are one of stainless steel, refractory, porous silicon carbide, phase change, and carbon steel components. The first layer 2 forms a receiving space for containing molten salt.

[0023] Understandably, stainless steel components possess characteristics such as high temperature resistance, molten salt corrosion resistance, and good weld sealing; refractory components, as a heat insulation layer, have low thermal conductivity, are resistant to thermal shock, significantly weaken solid-to-outside heat conduction, and suppress thermal bridging; porous silicon carbide components, through their interconnected porous framework, are stable at high temperatures, effectively increasing heat flow paths and interface scattering, further reducing equivalent thermal conductivity while possessing good strength; phase change components absorb heat and melt when the wall temperature of the high-temperature molten salt storage tank 1 rises, and release heat and solidify when the temperature drops, offsetting transient heat flow and reducing external heat dissipation and thermal shock; carbon steel components can provide overall mechanical strength and resistance to external loads, are easy to process, manufacture, install, and maintain, forming an external load-bearing and protective layer.

[0024] Meanwhile, during the operation of the high-temperature molten salt storage tank 1, the phase change element can store heat by absorbing heat and melting when the outer shell temperature rises to the phase change point, and release heat by exothermic solidification when the outer shell temperature drops below the phase change point. Thus, through this process of absorbing and releasing latent heat, the phase change element 6 can offset the transient heat flow caused by changes in the external ambient temperature, weaken temperature fluctuations, and further improve the thermal stability of the high-temperature molten salt storage tank 1. Furthermore, the phase change point of the phase change element, selected at 30℃–80℃, precisely covers the common temperature rise range of the outer wall of the high-temperature molten salt storage tank 1, enabling the phase change material to frequently participate in the heat absorption and release processes under actual operating conditions.

[0025] Therefore, by using one of the following materials for the outer shell: the first layer 2, the second layer 4, the third layer 5, the fourth layer 6, and the fifth layer 7, which are stainless steel, refractory, porous silicon carbide, phase change, and carbon steel components, a composite configuration is achieved. This enables the high-temperature molten salt storage tank 1 to have excellent heat preservation performance under high-temperature conditions and significantly suppress heat loss. The material gradient matching from the inside to the outside of the outer shell can reduce thermal stress concentration and improve structural durability, thereby effectively reducing the heat dissipation loss of the high-temperature molten salt storage tank 1 and enhancing the overall load-bearing and external load resistance performance, thus improving the long-term operational reliability of the high-temperature molten salt storage tank 1.

[0026] According to an embodiment of the present invention, the high-temperature molten salt thermal storage system includes a high-temperature molten salt storage tank 1 with an outer shell. The outer shell includes a first layer 2, a second layer 4, a third layer 5, a fourth layer 6, and a fifth layer 7 arranged sequentially from the inside out. The first layer 2, the second layer 4, the third layer 5, the fourth layer 6, and the fifth layer 7 are made of one of stainless steel, refractory, porous silicon carbide, phase change, and carbon steel. The first layer 2 forms a space for containing molten salt, so that the high-temperature molten salt storage tank 1 has excellent heat preservation performance under high-temperature conditions, effectively reduces the heat loss of the high-temperature molten salt storage tank 1, enhances the overall load-bearing and external load resistance performance, and improves the operational reliability of the high-temperature molten salt thermal storage system.

[0027] In some embodiments of the present invention, such as Figure 1 As shown, the first layer 2 is made of stainless steel, and the outer wall of the first layer 2 is equipped with a temperature detection device 3.

[0028] Understandably, stainless steel components are chosen because they are resistant to high temperatures, molten salt corrosion, and have good weld sealing properties. Using stainless steel in the innermost layer 2 ensures sealing and durability under long-term high-temperature molten salt conditions and effectively prevents corrosion of the structural materials by the molten salt. Simultaneously, a temperature detection device 3 is installed on the outer wall of the first layer 2 to detect the temperature of the molten salt within the containment space. This real-time monitoring data is transmitted to the automatic control device 17, providing reliable data support for subsequent molten salt circulation and control, thus ensuring the stability of the internal temperature field of the high-temperature molten salt storage tank 1.

[0029] In some embodiments of the present invention, such as Figure 1 As shown, the temperature detection device 3 includes multiple temperature sensors arranged along the height and circumferential directions of the high-temperature molten salt storage tank 1. Therefore, by arranging multiple temperature sensors along the height of the high-temperature molten salt storage tank 1, the temperature changes of the molten salt at different liquid levels within the storage space can be monitored in real time, reflecting the temperature difference between upper and lower layers of molten salt. Simultaneously, by arranging multiple temperature sensors along the circumferential direction of the high-temperature molten salt storage tank 1, the temperature conditions at different locations within the high-temperature molten salt storage tank 1 can be obtained, allowing for timely detection of temperature anomalies caused by uneven local heating or differences in heat exchange. Thus, by using multiple temperature sensors, the temperature detection device 3 can comprehensively acquire temperature field information of the molten salt within the storage space.

[0030] Furthermore, temperature sensor 3 is an ultrasonic temperature sensor, which further improves the reliability of monitoring.

[0031] In some embodiments of the present invention, such as Figure 1 As shown, the second layer 4 is a refractory component, which is an insulating brick. Therefore, the second layer 4 can serve as the main insulating layer outside the first layer 2. The insulating brick has the characteristics of low thermal conductivity and excellent thermal shock resistance. During the operation of the high-temperature molten salt storage tank 1, it can significantly reduce solid-to-outside heat conduction, thereby slowing down heat transfer. At the same time, it is not prone to cracking under thermal cycling, ensuring the long-term stability of the second layer 4 and further reducing heat loss from the high-temperature molten salt storage tank 1.

[0032] In some embodiments of the present invention, such as Figure 1 As shown, the third layer 5 is a porous silicon carbide component with a porosity of 40%-60%. Therefore, the third layer 5, through the porous framework of the silicon carbide component, can maintain a stable morphology at high temperatures and reduce the equivalent thermal conductivity by increasing heat flow paths and interface scattering, thereby further weakening heat conduction. Simultaneously, when the porosity of the porous silicon carbide component is controlled within the range of 40%–60%, sufficient mechanical strength can be maintained while significantly reducing thermal conductivity, avoiding material fragility due to excessive porosity or insufficient thermal insulation performance due to excessively low porosity. Thus, the third layer 5 achieves a balance between thermal insulation performance and structural strength, ensuring that the high-temperature molten salt storage tank 1 maintains stable shell support performance under high-temperature conditions.

[0033] In some embodiments of the present invention, such as Figure 1 As shown, the fifth layer, 7, is made of carbon steel. Therefore, the fifth layer, 7, serves as both an external load-bearing and protective layer. The carbon steel components provide overall mechanical strength and resistance to external impacts, ensuring the storage tank maintains structural stability even under external loads or environmental disturbances. Simultaneously, the carbon steel components are easy to process, weld, and install, reducing manufacturing and maintenance costs and improving assembly reliability.

[0034] In some embodiments of the present invention, such as Figure 1As shown, the fourth layer 6 is a phase change element with a phase change point of 30℃-80℃. Therefore, during the operation of the high-temperature molten salt storage tank 1, when the outer shell temperature rises to the phase change point, the fourth layer 6 can store heat through endothermic melting; when the outer shell temperature drops below the phase change point, it can release heat through exothermic solidification. Thus, through this process of absorbing and releasing latent heat, the fourth layer 6 can offset the transient heat flow caused by changes in the external ambient temperature, weaken temperature fluctuations, and further improve the thermal stability of the high-temperature molten salt storage tank 1. At the same time, the phase change point of 30℃–80℃ for the phase change element precisely covers the common temperature rise range of the outer wall of the high-temperature molten salt storage tank 1, enabling the phase change material to frequently participate in the heat absorption and release processes under actual operating conditions.

[0035] In some embodiments of the present invention, such as Figure 1 As shown, the phase change element is a phase change capsule. Therefore, by encapsulating the material, the phase change material can maintain its morphological stability during multiple solid-liquid phase change cycles, avoiding material leakage and loss. Simultaneously, the capsule shell provides additional mechanical support, giving the phase change element high structural stability during operation, thereby extending its service life and improving reliability.

[0036] In some embodiments of the present invention, such as Figure 1 As shown, the phase change element is paraffin wax. It is understandable that paraffin wax, as a common phase change material, has advantages such as high latent heat of phase change, moderate phase change temperature range, low cost, and stable chemical properties. Applying paraffin wax to the fourth layer 6 can not only significantly improve the temperature buffering effect of the high-temperature molten salt storage tank 1, but also reduce costs.

[0037] In some embodiments of the present invention, such as Figure 1 As shown, the high-temperature molten salt thermal storage system also includes a liquid distribution ring pipe 13 and a salt inlet pipe 8. The liquid distribution ring pipe 13 is located at the bottom of the containing space and is annular. The liquid distribution ring pipe 13 has multiple nozzles 14, which are spaced apart along the circumferential direction of the liquid distribution ring pipe 13. One end of the salt inlet pipe 8 extends into the containing space and is connected to the liquid distribution ring pipe 13 for conveying molten salt into the liquid distribution ring pipe 13.

[0038] Thus, molten salt enters the distribution ring pipe 13 through the salt inlet pipe 8, and is then sprayed into the containment space of the high-temperature molten salt storage tank 1 by multiple nozzles 14 on the distribution ring pipe 13. This allows the molten salt to be evenly distributed at the bottom of the high-temperature molten salt storage tank 1 and enter the containment space tangentially, effectively reducing local overheating inside the high-temperature molten salt storage tank 1 and promoting mixing between the bottom molten salt and the upper molten salt. This effectively breaks the natural stratification effect inside the high-temperature molten salt storage tank 1 and improves the heat storage effect.

[0039] In some embodiments of the present invention, such as Figure 1As shown, the nozzle 14 makes an acute angle with the horizontal direction and an acute angle with the vertical direction. Along the horizontal direction, the ends of the multiple nozzles 14 that are away from the liquid distribution ring pipe 13 extend in the same tangential direction in the circumferential direction of the liquid distribution ring pipe 13.

[0040] Thus, along the horizontal direction, multiple nozzles 14 extend in the same tangential direction toward the circumferential direction of the liquid distribution ring pipe 13 from one end away from the liquid distribution ring pipe 13, so that the nozzles 14 can spray molten salt into the containing space of the high-temperature molten salt storage tank 1 in a tangential manner, thereby forming an overall unidirectional rotating flow field inside the containing space, effectively enhancing the heat transfer between molten salts.

[0041] By using an acute angle between nozzle 14 and the horizontal direction, the molten salt flow ejected from nozzle 14 has a larger tangential velocity component relative to the distribution ring pipe 13. This makes it easier to form a rotating flow field inside the high-temperature molten salt storage tank 1. The acute angle between nozzle 14 and the vertical direction ensures that the jet from nozzle 14 carries a vertical component in addition to tangential motion. This allows the high-temperature molten salt ejected from the bottom to move upwards and mix with the lower-temperature molten salt above, thus reducing temperature stratification. Simultaneously, this design effectively prevents nozzle 14 from spraying at approximately 90° directly onto the inner wall of the storage space, reducing the risk of localized impact and erosion on the first layer 2. This contributes to improving the operational stability and structural lifespan of the high-temperature molten salt storage tank 1.

[0042] It should be noted that the vertical direction is the same as the height direction of the high-temperature molten salt storage tank 1. Figure 1 The up and down directions are shown in the diagram.

[0043] In some embodiments of the present invention, such as Figure 1 As shown, the angle between nozzle 14 and the horizontal direction is the same as the angle between nozzle 14 and the vertical direction. This arrangement ensures that the molten salt flow ejected from nozzle 14 has the same component in both the tangential and vertical directions, resulting in a symmetrical and stable spiral flow field after the molten salt enters the high-temperature molten salt storage tank 1, further enhancing the stability and uniformity of the flow.

[0044] In some embodiments of the present invention, such as Figure 1As shown, the angle between nozzle 14 and the horizontal direction is 15°–75°. It is understandable that when the angle between nozzle 14 and the horizontal direction is less than 15°, the jet stream is almost parallel to the distribution ring pipe 13, resulting in insufficient swirling flow intensity of the molten salt within the high-temperature molten salt storage tank 1, poor vertical stirring effect, and difficulty in effectively breaking up temperature stratification. Conversely, when the angle between nozzle 14 and the horizontal direction is greater than 75°, the jet stream is almost perpendicular to the distribution ring pipe 13, causing the molten salt to directly impact the first layer 2, easily leading to localized impact and erosion risks. Therefore, selecting an angle between nozzle 14 and the horizontal direction within the range of 15°–75° balances tangential rotational drive and vertical disturbance mixing, thereby enhancing molten salt stirring while avoiding localized damage.

[0045] It should be noted that the angle between the nozzle 14 and the horizontal direction can be 15°, 25°, 35°, 45°, 55°, 65° or 75°. Among them, when the angle is 45°, the tangential component and the vertical component of the jet flow are relatively balanced, which can form the best spiral swirl flow effect.

[0046] In some embodiments of the present invention, such as Figure 1 As shown, the angle between nozzle 14 and the vertical direction is 15°-75°.

[0047] Understandably, when the angle between nozzle 14 and the vertical direction is less than 15°, the jet stream is almost vertically downward, with insufficient tangential component, making it difficult to form a strong rotating flow field within the capacity of the high-temperature molten salt storage tank 1, thus weakening the stirring effect on the molten salt. Conversely, when the angle between nozzle 14 and the vertical direction is greater than 75°, the jet stream is almost horizontal, with insufficient vertical disturbance, making it difficult for the upper and lower layers of molten salt to mix fully, and the temperature stratification problem is difficult to eliminate. Therefore, limiting the angle between nozzle 14 and the vertical direction to between 15° and 75° can increase appropriate vertical disturbance while maintaining rotational drive, thereby balancing circumferential rotation and vertical mixing, and improving temperature uniformity.

[0048] It should be noted that the angle between the nozzle 14 and the vertical direction can be 15°, 25°, 35°, 45°, 55°, 65° or 75°. When the angle is 45°, the rotation of the jet and the vertical disturbance are in better balance, which can achieve the best molten salt mixing effect.

[0049] In some embodiments of the present invention, such as Figure 1As shown, multiple nozzles 14 are respectively located on both sides of the liquid distribution ring pipe 13 along the vertical direction. Thus, the nozzles 14 can simultaneously spray molten salt from both the upper and lower sides of the liquid distribution ring pipe 13 into the containing space of the high-temperature molten salt storage tank 1, avoiding stagnation in the upper and lower areas of the liquid distribution ring pipe 13. Furthermore, through the synergistic effect of the spray from the upper and lower sides, the lower layer of molten salt can be driven to rise and the upper layer of molten salt can be driven to fall simultaneously, further promoting the full mixing of the upper and lower layers of molten salt. This further reduces the temperature stratification phenomenon inside the high-temperature molten salt storage tank 1, and also evenly distributes the molten salt flow in the radial, circumferential, and vertical directions, improving the heat storage efficiency and operational stability of the entire high-temperature molten salt storage tank 1.

[0050] In some embodiments of the present invention, such as Figure 1 As shown, the high-temperature molten salt thermal storage system also includes an extension pipe 18, a circulating salt pipe 10, a salt outlet pipe 9, a circulating salt automatic control valve 15, a salt outlet automatic control valve 16, and a molten salt pump 11.

[0051] The extension pipe 18 extends along the height of the containment space. One end of the extension pipe 18 extends into the bottom of the containment space, and the other end is connected to the circulating salt pipe 10 and the salt outlet pipe 9 respectively. The other end of the circulating salt pipe 10 extends into the containment space. The lowest point of the circulating salt pipe 10 in the containment space is higher than the lowest point of the extension pipe 18 in the containment space. The circulating salt automatic control valve 15 is connected in series between the extension pipe 18 and the circulating salt pipe 10. The salt outlet automatic control valve 16 is connected in series on the salt outlet pipe 9. The molten salt pump 11 is connected to the extension pipe 18 and is used to pump the molten salt in the containment space into the extension pipe 18 and transport it through the circulating salt pipe 10 or the salt outlet pipe 9.

[0052] Understandably, when the temperature difference between the upper and lower layers of molten salt inside the high-temperature molten salt storage tank 1 reaches a set threshold, the system can issue a command through the automatic control device 17: close the automatic salt outlet regulating valve 16 on the salt outlet pipe 9, open the automatic circulating salt regulating valve 15 on the circulating salt pipe 10, and start the molten salt pump 11, so that the high-temperature molten salt at the bottom is pumped into the circulating salt pipe 10 along the extension pipe 18, and then flows back to the upper part of the containing space through the circulating salt pipe 10, so that the high-temperature molten salt at the bottom mixes with the low-temperature molten salt at the top, thereby reducing the temperature difference inside the high-temperature molten salt storage tank 1, maintaining the uniformity of the high-temperature molten salt storage tank 1, and improving the heat storage effect.

[0053] When it is necessary to transport the molten salt in the high-temperature molten salt storage tank 1 to an external heat exchange or energy storage system, the system can issue an instruction through the automatic control device 17: close the circulating salt automatic control valve 15, open the salt outlet automatic control valve 16 on the salt outlet pipe 9, and drive the molten salt pump 11 so that the bottom molten salt is pumped along the extension pipe 18 and discharged through the salt outlet pipe 9.

[0054] Therefore, the high-temperature molten salt thermal storage system can reduce the temperature difference by supplying high-temperature molten salt from the bottom to the upper layer of the storage space through the circulating salt pipe 10, and can also complete the normal output of molten salt through the salt outlet pipe 9 when needed, ensuring that the thermal storage system can balance the stability and flexibility of operation in terms of both regulation and output.

[0055] In some embodiments of the present invention, such as Figure 1 As shown, the high-temperature molten salt thermal storage system also includes a control device 17, which is communicatively connected to at least one of the circulating salt automatic regulating valve 15, the salt outlet automatic regulating valve 16, and the molten salt pump 11.

[0056] Understandably, the control device 17 enables a closed-loop connection between the temperature signal collected by the temperature detection device 3 and the molten salt flow control device, thereby transforming the high-temperature molten salt storage tank 1 from manual operation to automatic regulation mode. Through intelligent control of the valves and molten salt pump 11 by the control device 17, rapid response can be achieved under complex operating conditions, avoiding temperature difference expansion or operational instability caused by delays or errors in human operation. Therefore, the control device 17 not only improves the system's operating efficiency but also enhances its operational safety and stability.

[0057] Specifically, when the control device 17 receives a signal from the temperature detection device 3 indicating that the temperature difference between the upper and lower layers of molten salt inside the high-temperature molten salt storage tank 1 exceeds a set threshold, the control device 17 will issue a control command: close the automatic salt outlet regulating valve 16, open the automatic circulating salt regulating valve 15, and start the molten salt pump 11. This allows the high-temperature molten salt at the bottom to be pumped through the extension pipe 18 to the circulating salt pipe 10, and then back to the upper part of the high-temperature molten salt storage tank 1, thereby achieving mixing between the bottom and upper layers of molten salt and reducing the temperature difference. Simultaneously, during the circulation process, the control device 17 can flexibly control the flow rate of the circulating molten salt by dynamically adjusting the speed of the molten salt pump 11 and the opening degree of the automatic circulating salt regulating valve 15, enabling the circulation intensity to adapt to different temperature difference levels, further improving the accuracy and efficiency of temperature control, and rapidly reducing the temperature difference inside the high-temperature molten salt storage tank 1.

[0058] When the internal temperature difference of the high-temperature molten salt storage tank 1 is within the allowable range and the system needs to output molten salt to the outside, the control device 17 will issue a command: close the automatic circulating salt control valve 15, open the automatic salt output control valve 16, and drive the molten salt pump 11 to discharge the molten salt through the salt output pipe 9 for use in external heat exchange or energy storage systems. Through the above intelligent switching, the high-temperature molten salt storage tank 1 can flexibly switch between automatic circulation control and normal salt output, ensuring the high efficiency and stability of the high-temperature molten salt thermal energy storage system during heat storage and output processes.

[0059] The high-temperature molten salt thermal storage system of this application, through the coordinated arrangement of the extension pipe 18, the circulating salt pipe 10, the salt outlet pipe 9, the molten salt pump 11, and the automatic control device 17, forms a dual circulation of internal and external molten salt. This enables active mixing when there is a large temperature difference between the upper and lower layers inside the high-temperature molten salt storage tank 1, significantly reducing temperature stratification attenuation. Simultaneously, the composite insulation structure of the outer shell and the active temperature regulation effect of the fourth-layer six-phase change element effectively reduce heat loss. Therefore, the overall thermal storage performance of the high-temperature molten salt storage tank 1 is improved, and the safety and reliability of the high-temperature molten salt thermal storage system operation are enhanced.

[0060] In some embodiments, such as ​ As shown, the high-temperature molten salt thermal storage system also includes a molten salt heater 12, which is used to assist in regulating the temperature change of the molten salt inside the high-temperature molten salt storage tank 1, so as to ensure that the molten salt temperature is maintained within a suitable operating range.

[0061] It is understandable that when the overall temperature of the molten salt inside the high-temperature molten salt storage tank 1 is lower than the set value, the molten salt heater 12 can heat the molten salt to avoid the molten salt temperature being too low and affecting the heat storage and output effect.

[0062] Furthermore, the molten salt heater 12 is preferably an electric heater, which can quickly compensate for heat loss during operation through electric heating, has high control precision and fast response speed, and can work in conjunction with the control device 17 to improve the temperature regulation flexibility and stability of the high-temperature molten salt thermal storage system.

[0063] Furthermore, the molten salt heater 12 is located at the bottom of the containment space. Thus, the molten salt heater 12 can directly heat the molten salt at the bottom of the containment space of the high-temperature molten salt storage tank 1. Since the temperature of the molten salt at the bottom is often higher than that of the upper molten salt, by installing the molten salt heater 12 at the bottom, the heat of the molten salt at the bottom can be quickly replenished when the system needs it. With the driving action of the circulating salt pipe 10 and the molten salt pump 11, the heated high-temperature molten salt is transported to the upper part, thereby accelerating the temperature equalization process and further improving the stability and uniformity of the molten salt temperature field.

[0064] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0065] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A high-temperature molten salt thermal storage system, characterized in that, include: A high-temperature molten salt storage tank has an outer shell, which includes a first layer, a second layer, a third layer, a fourth layer, and a fifth layer arranged sequentially from the inside out. The first layer, the second layer, the third layer, the fourth layer, and the fifth layer are made of one of stainless steel, refractory, porous silicon carbide, phase change, and carbon steel. The first layer forms a containment space for accommodating the molten salt.

2. The high-temperature molten salt thermal storage system according to claim 1, characterized in that, The first layer is made of stainless steel, and a temperature detection device is provided on the outer wall of the first layer.

3. The high-temperature molten salt thermal storage system according to claim 2, characterized in that, The temperature detection device includes multiple temperature sensors, which are arranged along the height and circumferential directions of the high-temperature molten salt storage tank.

4. The high-temperature molten salt thermal storage system according to claim 1, characterized in that, The second layer is a refractory component, which is a heat-insulating brick; And / or, the third layer is a porous silicon carbide component, the porosity of which is 40%-60%; And / or, the fifth layer is a carbon steel component.

5. The high-temperature molten salt thermal storage system according to claim 1, characterized in that, The fourth layer is a phase change element, and the phase change point of the phase change element is 30℃-80℃; And / or, the phase change element is a phase change capsule; And / or, the phase change element is paraffin wax.

6. The high-temperature molten salt thermal storage system according to claim 1, characterized in that, Also includes: A liquid distribution ring tube is located at the bottom of the receiving space and is annular. The liquid distribution ring tube has multiple nozzles, which are spaced apart along the circumferential direction of the liquid distribution ring tube. A salt inlet pipe, one end of which extends into the accommodating space and is connected to the liquid distribution ring pipe, is used to deliver molten salt into the liquid distribution ring pipe.

7. The high-temperature molten salt thermal storage system according to claim 6, characterized in that, The nozzle makes an acute angle with the horizontal direction and an acute angle with the vertical direction. Along the horizontal direction, the ends of the multiple nozzles that are away from the liquid distribution ring pipe extend toward the same tangential direction in the circumferential direction of the liquid distribution ring pipe.

8. The high-temperature molten salt thermal storage system according to claim 7, characterized in that, The angle between the nozzle and the horizontal direction is the same as the angle between the nozzle and the vertical direction; And / or, the angle between the nozzle and the horizontal direction is 15°-75°; And / or, the angle between the nozzle and the vertical direction is 15°-75°; And / or, the plurality of nozzles are respectively disposed on both sides of the liquid distribution ring pipe along the vertical direction.

9. The high-temperature molten salt thermal storage system according to claim 6, characterized in that, Also includes: An extension tube extends along the height direction of the receiving space. One end of the extension tube extends into the bottom of the receiving space, and the other end is connected to the circulating salt tube and the salt outlet tube respectively. The other end of the circulating salt tube extends into the receiving space. The lowest point of the circulating salt tube in the receiving space is higher than the lowest point of the extension tube in the receiving space. An automatic circulating salt control valve is connected in series between the extension pipe and the circulating salt pipe; An automatic salt outlet regulating valve is connected in series on the salt outlet pipe; A molten salt pump, connected to the extension pipe, is used to pump molten salt from the containment space into the extension pipe and transport it through the circulating salt pipe or the outlet salt pipe.

10. The high-temperature molten salt thermal storage system according to claim 9, characterized in that, Also includes: A control device, which is communicatively connected to at least one of the circulating salt automatic control valve, the salt outlet automatic control valve, and the molten salt pump.

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