Fused salt heating system, fused salt heating method, and photovoltaic-photothermal coupling system

Abstract

The application provides a molten salt heating system, a molten salt heating method and a photovoltaic-photothermal coupling system, wherein the molten salt heating system comprises a first heating device, a second heating device and a jet flow assembly located between the first heating device and the second heating device; the molten salt is subjected to primary heating in the first heating device, moves in a horizontal direction to the second heating device, and enters the jet flow assembly in a fluid form to be pressurized, and is injected into the second heating device to be subjected to secondary heating to reach a target heating temperature. The molten salt heating system provided by the application can improve heat exchange uniformity, reduce equipment cost and enhance the adaptability of a high-voltage electric heating device in a photovoltaic-photothermal complementary power generation system through multi-stage heating and molten salt impact jet flow.

Description

Technical Field

[0001] This invention relates to the field of solar power generation, and more specifically, to a molten salt heating system, a molten salt heating method, and a photovoltaic-photothermal coupling system. Background Technology

[0002] Currently, photovoltaic-solar thermal complementary power generation coupling methods mainly include: 1) using photovoltaic power to supply power to auxiliary equipment of the solar thermal power generation system; 2) providing stable power to users by distributing power between photovoltaic and solar thermal power plants; 3) using the heat dissipation of the photovoltaic system to provide heat to the solar thermal power generation system; and 4) using spectral splitting technology to rationally distribute the wavelengths of sunlight received by photovoltaic and solar thermal systems. Among these, the second method, which combines photovoltaic and solar thermal power solely through operation and scheduling, is the most commercially viable photovoltaic-solar thermal complementary power generation method.

[0003] For the second type of photovoltaic-solar thermal coupling method, in addition to coupling on the grid side, the photovoltaic and solar thermal power plants in the complementary power generation system can also recover part or all of the curtailed photovoltaic power and convert it into heat energy, which is then stored in the thermal storage system of the solar thermal power plant, thus achieving deep coupling between the photovoltaic and solar thermal power plants. Among these, the electric heater equipment is one of the core components of the entire system, and its performance significantly affects the operational safety and economy of the entire system.

[0004] Currently, commercial electric heating equipment mainly suffers from the following problems: 1) It adopts a low-voltage design, which cannot achieve large-scale curtailment of solar power, and also has problems such as high power distribution costs and poor power plant economics; 2) It adopts a high-voltage design, which results in poor heat exchange uniformity, easily forming local high temperatures, and the electric heating tube is easily damaged by breakdown; the cost of electric heaters with integrated design is high.

[0005] Patent CN110360863A discloses an electrically heated solid-medium energy storage device, including a high-voltage power supply, a hot solid-medium tank, a cold solid-medium tank, a solid-medium lifting device, a feeding chamber, and at least one heater and at least one heat exchanger; the heater and heat exchanger use a solid heat storage medium as the heat exchange medium. The inlet of the hot solid-medium tank is connected to the heater via a regulating valve, and the outlet of the hot solid-medium tank is connected to the heat exchanger via multiple pipes, each equipped with a regulating valve. The inlet and outlet of the cold solid-medium tank are connected to the heat exchanger and the feeding chamber, respectively. The heater inlet is connected to the solid-medium lifting device, and the heater is connected to a high-voltage power supply. This application discloses a molten salt heating and heat exchange system but does not provide a solution for improving the heat exchange of molten salt from the perspective of the heater's internal structure.

[0006] Patent CN209506661U discloses a molten salt storage tank with built-in electric heating and a heater, including an electric heating device, a heater, a thermocouple, a stirrer, and a storage tank. The electric heating device uses electricity to generate heat to heat the molten salt in the storage tank; a high-temperature fluid is introduced into the heater to heat the molten salt. The thermocouple monitors the molten salt temperature and controls the operation of the electric heating device and the heater. The stirrer ensures a uniform temperature distribution of the molten salt within the storage tank. This patent discloses a molten salt heating device with multiple heating rods, but it requires a stirrer to improve the uniformity of the molten salt temperature distribution; furthermore, its integrated structure results in higher equipment costs.

[0007] In view of the above technical problems, this invention is hereby introduced. Summary of the Invention

[0008] The main objective of this invention is to provide a molten salt heating system, a molten salt heating method, and a photovoltaic-photothermal coupling system, which improves the uniformity of molten salt heating temperature, reduces costs, and enhances the adaptability of high-voltage electric heating devices in photovoltaic-photothermal complementary power generation systems.

[0009] To achieve the above objectives, the present invention provides a molten salt heating system, including a first heating device, a second heating device, and a jet assembly located between the first heating device and the second heating device. Molten salt is first-stage heated in the first heating device, moves horizontally toward the second heating device, and enters the jet assembly in fluid form for pressurization, and is injected into the second heating device for secondary heating to reach the target heating temperature.

[0010] Furthermore, the first heating device includes a first cavity and a heating assembly located inside the first cavity. The heating assembly includes a first group of heating rods and a second group of heating rods distributed along both sides of the axial direction of the first cavity, and the first group of heating rods and the second group of heating rods form an interlaced vortex region.

[0011] Furthermore, the first group of heating rods and the second group of heating rods each include multiple first heating rods and multiple second heating rods that are periodically distributed along the axial direction of the first cavity. The first heating rods and the second heating rods are arranged in parallel and staggered. A first vortex region is formed between adjacent first heating rods, and a second vortex region is formed between adjacent second heating rods.

[0012] Furthermore, the first heating device also includes a first feed inlet, which is connected to the first vortex region. Molten salt enters the first cavity through the first feed inlet, propelling the molten salt in the first vortex region toward the axis closer to the first cavity.

[0013] Furthermore, the first heating device also includes a second feed inlet, which is connected to the second vortex region, and propels the molten salt in the second vortex region toward the axis closer to the first cavity.

[0014] Furthermore, the first heating device also includes a third feed port, which coincides with the axis of the first cavity. Molten salt enters the first cavity through the third feed port, propelling the molten salt in the axis region toward the second heating device.

[0015] Furthermore, the cross-sectional area of ​​the third feed inlet is larger than that of the first and second feed inlets.

[0016] Furthermore, the cross-sectional areas of the first, second, and third feed inlets increase along the direction of molten salt entry.

[0017] Furthermore, the first heating device also includes a distributor connected to a first feed inlet, a second feed inlet, and a third feed inlet.

[0018] Furthermore, the second heating device includes a second cavity and a third heating rod located inside the second cavity. Molten salt is injected toward the third heating rod to form an impact jet on the surface of the third heating rod.

[0019] Furthermore, the jet assembly includes a spacer between the first cavity and the second cavity and a nozzle located on the spacer.

[0020] Furthermore, it also includes a buffer device, into which the molten salt, after being heated in two stages, is stored.

[0021] Furthermore, the buffer device includes a heated buffer cavity, multiple buffer tanks located in the central area of ​​the heated buffer cavity, and a fourth heating rod near the inner wall of the heated buffer cavity, the fourth heating rod radiating heat to the buffer tanks.

[0022] Furthermore, the buffer device also includes a distributor from which molten salt is fed into multiple buffer tanks.

[0023] Furthermore, the buffer device also includes a dispensing pipe that connects the distributor and the buffer tank.

[0024] The molten salt heating system proposed in this invention achieves the following technical effects:

[0025] 1. Multi-stage heating is adopted to improve the uniformity of molten salt temperature by gradually increasing the temperature, and to reduce the material and manufacturing costs of the heating device, thereby enhancing the adaptability of the high-voltage electric heating device in solar power generation systems.

[0026] 2. By setting jet components between multi-stage heating devices, molten salt impact jets are formed, which enhances the heat exchange of molten salt in the heating device.

[0027] 3. By arranging heating rods in an alternating pattern, periodic vortex regions are formed, which promotes full mixing of the fluid in the alternating vortex regions, increases turbulence, and thus increases the convective heat transfer coefficient, so that the heat from the heating rods is continuously and rapidly removed.

[0028] 4. The multi-channel feeding structure with vertically arranged feed inlets promotes the movement of molten salt in the first chamber, quickly removes the heat exchange fluid, enhances heat transfer, avoids local high temperature in the heating rod, and improves the temperature uniformity of the flow field.

[0029] 5. Add a buffer device with a radiant heating design for non-contact heat transfer to keep the molten salt in the buffer tank warm.

[0030] The second aspect of the application proposes a molten salt heating method, comprising the following steps: S1, molten salt enters a first heating device through a feed port for primary heating; S2, the molten salt after primary heating is pressurized by a jet assembly and injected into a second heating device for secondary heating; S3, the molten salt after secondary heating enters a buffer device for buffering.

[0031] Furthermore, in step S1, the molten salt is heated in the staggered vortex region formed in the first cavity, and then the molten salt entering the first cavity through the first feed port, the second feed port and the third feed port moves the molten salt in the vortex region toward the second cavity.

[0032] The molten salt heating method proposed in this invention achieves the following technical effects:

[0033] 1. Multi-stage heating is adopted to gradually increase the temperature of the molten salt, thereby avoiding local overheating and enhancing the adaptability of the high-voltage electric heating device in the solar power generation system.

[0034] 2. By setting jet components between multi-stage heating devices, molten salt impact jets are formed, which enhances the heat exchange of molten salt in the heating device.

[0035] 3. Molten salt forms a vortex region between the heating rods. Then, the molten salt entering through the vertically distributed feed inlets propels the molten salt in the vortex region of the first chamber toward the second chamber, quickly carrying away the heat exchange fluid, enhancing heat transfer, avoiding local high temperatures in the heating rods, and improving the temperature uniformity of the flow field.

[0036] 4. An additional buffering step is added, employing a radiant heating design for non-contact heat transfer to keep the molten salt in the buffer tank warm.

[0037] The third aspect of the application proposes a photovoltaic-photothermal coupling system, including a molten salt heating system, which converts at least a portion of the abandoned photovoltaic power into thermal energy and stores it in the thermal storage system of a solar thermal power plant.

[0038] The photovoltaic-photothermal coupling system proposed in this invention achieves the following technical effects:

[0039] 1. The photovoltaic-photothermal coupling system adopts a molten salt heating system, which improves the uniformity of molten salt temperature, reduces the material and manufacturing costs of the heating device, and enhances the adaptability of the high-voltage electric heating device in the solar power generation system.

[0040] 2. The photovoltaic-photothermal coupling system forms a periodic vortex region by arranging heating rods in an alternating manner, which promotes the full mixing of fluid in the alternating vortex region, increases the turbulence intensity, and thus increases the convective heat transfer coefficient, so that the heat of the heating rods is continuously and rapidly removed.

[0041] 3. The molten salt heating system in the photovoltaic-photothermal coupling system adopts a multi-channel feeding structure with vertically arranged feed inlets, which promotes the movement of molten salt in the first cavity, quickly removes the heat exchange fluid, enhances heat transfer, avoids local high temperature of the heating rod, and improves the temperature uniformity of the flow field.

[0042] 4. The molten salt heating system in the photovoltaic-photothermal coupling system is equipped with a buffer device, which adopts a radiation heating design and non-contact heat transfer to keep the molten salt in the buffer tank warm. Attached Figure Description

[0043] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0044] Figure 1 This diagram shows the structure of the molten salt heating system of this application;

[0045] Figure 2 A flowchart illustrating the molten salt heating method of this application is shown.

[0046] The above figures include the following reference numerals:

[0047] 100. First heating device; 200. Second heating device; 110. First cavity; 122. First heating rod; 124. Second heating rod; 130. First feed inlet; 140. Second feed inlet; 150. Third feed inlet; 160. Distributor; 220. Second cavity; 222. Third heating rod; 310. Spacer plate; 320. Nozzle; 400. Buffer device; 420. Heated buffer cavity; 422. Buffer tank; 424. Fourth heating rod; 426. Liquid distributor; 428. Liquid distribution pipe. Detailed Implementation

[0048] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0049] The present invention will be further described in detail below with reference to specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed by the present invention. The term "comprising" indicates the presence of a feature, but does not exclude the presence or addition of one or more other features. The terms "lateral," "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the purpose of 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 present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0050] In this description, 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 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 these terms in this invention based on the specific circumstances. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0051] Example 1:

[0052] To address the issues of uneven molten salt heating temperature and high cost of integrated structures in traditional heaters, this application proposes a molten salt heating system that achieves step-by-step heating of the molten salt through multi-stage heating and adopts a split heating structure to reduce heater manufacturing costs.

[0053] Specifically, the molten salt heating system includes a first heating device 100 and a second heating device 200. Molten salt undergoes primary heating in the first heating device 100 and secondary heating in the second heating device 200. The primary heating temperature is lower than the secondary heating temperature. A split design reduces the material and manufacturing costs of the primary heating device, and the gradual heating improves the uniformity of the molten salt temperature. In this application, both the first heating device 100 and the second heating device 200 adopt a horizontal structure to reduce the influence of gravity on the movement of the molten salt, lower the flow rate of the molten salt, and ensure more efficient heat exchange, avoiding problems such as large temperature differences between the top and bottom of a vertical structure. This application does not specify a particular number of heating devices; the number of heating devices can be increased according to actual heating needs.

[0054] In addition, to further improve the heat exchange effect, the heating system also adds a jet assembly between the first heating device 100 and the second heating device 200. The molten salt heated by the first heating device 100 moves horizontally toward the direction closer to the second heating device 200 and enters the jet assembly for pressurization. The jet assembly forms a molten salt impact jet, which enhances the heat exchange of the molten salt in the second heating device.

[0055] To improve the heat exchange effect of molten salt in the first heating device 100, this application optimizes the arrangement of heating rods in the first heating device 100.

[0056] Specifically, the first heating device 100 includes a first cavity 110 and a heating assembly located inside the first cavity 110. The heating assembly includes a first group of heating rods and a second group of heating rods distributed along both sides of the axial direction of the first cavity 110.

[0057] The first and second sets of heating rods each include multiple first heating rods 122 and multiple second heating rods 124 periodically distributed along the axial direction of the first cavity 110. The first heating rods 122 and second heating rods 124 are arranged parallel and staggered. A first vortex region is formed between adjacent first heating rods 122, and a second vortex region is formed between adjacent second heating rods 124. Thus, the first and second vortex regions are staggered on both sides along the axial direction of the first cavity 110. This application adopts an intermittent electric heating rod design to form periodic vortex regions, which enhances the convective heat transfer coefficient of molten salt between the heating rods, thereby improving the heat transfer effect. Regional fixed vortices are formed in the staggered vortex regions, which promotes the full mixing of fluid in the staggered vortex regions, increases turbulence, and further increases the convective heat transfer coefficient, so that the heat of the heating rods is continuously and rapidly removed.

[0058] To facilitate the movement of molten salt from the first chamber to the second chamber and to further improve the heat exchange effect of the molten salt in the first chamber, this application proposes a heating device including multiple feed ports.

[0059] Specifically, the first heating device 100 includes a first inlet 130 and a second inlet 140. The first inlet 130 connects to the first vortex region and is close to the boundary layer of the first vortex region, and the second inlet 140 connects to the second vortex region and is close to the boundary layer of the second vortex region. Molten salt enters the first cavity 110 through the first inlet 130 and the second inlet 140, propelling the molten salt in the first vortex region and the second vortex region toward the axis close to the first cavity 110.

[0060] By setting the feed inlet near the vortex region, the movement and heat exchange of molten salt in the vortex region are promoted; the boundary effect of molten salt in the first cavity is alleviated, and the uniformity of molten salt heating is further improved; the molten salt after heat exchange leaves the vortex region, avoiding local high temperature.

[0061] In addition, the first heating device 100 also includes a third feed port 150, which is aligned with the axis of the first cavity 110. Molten salt enters the first cavity 110 through the third feed port 150, and moves the molten salt in the axis region closer to the second heating device 200.

[0062] To ensure that the molten salt moves axially along the first cavity, the cross-sectional area of ​​the third inlet 150 in this application should be greater than the cross-sectional area of ​​the first inlet 130 and the second inlet 140, and the flow rate of the molten salt in the first cavity can be controlled by adjusting the size of the third inlet 150 and the first inlet 130 and the second inlet 140.

[0063] To prevent molten salt from clogging the feed area, the cross-sectional areas of the first feed port 130, the second feed port 140, and the third feed port 150 in this application are increased along the direction of molten salt entry.

[0064] This application adopts a multi-channel feeding structure, with the first feed port 130, the second feed port 140 and the third feed port 150 arranged vertically to promote the movement of molten salt in the first cavity, quickly carry away the heat exchange fluid, enhance heat transfer, avoid local high temperature of the heating rod, and greatly improve the temperature uniformity of the flow field.

[0065] In another embodiment of the application, the first heating device 100 further includes a distributor 160, which is connected to a first feed port 130, a second feed port 140, and a third feed port 150. Molten salt enters the distributor 160 through an inlet pipe and is distributed to each feed port by the distributor 160, thereby improving the uniformity of molten salt distribution.

[0066] In one embodiment of the application, the second heating device 200 includes a second cavity 220 and a third heating rod 222 located inside the second cavity 220. Molten salt is injected toward the third heating rod 222 to form an impact jet on the surface of the third heating rod 222.

[0067] Furthermore, the jet assembly includes a spacer plate 310 located between the first chamber 110 and the second chamber 220, and a nozzle 320 located on the spacer plate 310. Molten salt is jetted into the second chamber through the nozzle 320 to improve heat exchange efficiency. The nozzle and the spacer plate are flexibly connected, facilitating nozzle assembly and replacement.

[0068] In addition, the molten salt heating system of this application is equipped with a buffer device 400, and the molten salt after the secondary heating enters the buffer device 400 for pre-heating and buffering.

[0069] The buffer device 400 includes a heated buffer chamber 420, multiple buffer tanks 422 located in the central area of ​​the heated buffer chamber 420, and a fourth heating rod 424 near the inner wall of the heated buffer chamber 420, which radiates heat to the buffer tanks 422. A non-contact heat transfer method using radiant heating is employed, heating the gas within the buffer chamber to maintain the temperature of the buffer tanks. The molten salt in the buffer tanks is reheated to ensure uniform temperature. Once the molten salt reaches the target temperature, a valve located at the bottom of the buffer tank is opened to transfer the molten salt into a subsequent molten salt storage tank.

[0070] In one embodiment of the application, the buffer device 400 further includes a distributor 426 and a distribution pipe 428. Molten salt enters multiple buffer tanks 422 from the distributor 426 and the distribution pipe 428, ensuring that the molten salt is evenly distributed to each buffer tank.

[0071] The molten salt heating system proposed in this invention achieves the following technical effects:

[0072] 1. Multi-stage heating is adopted to improve the uniformity of molten salt temperature by gradually increasing the temperature, and to reduce the material and manufacturing costs of the heating device, thereby enhancing the adaptability of the high-voltage electric heating device in solar power generation systems.

[0073] 2. By setting jet components between multi-stage heating devices, molten salt impact jets are formed, which enhances the heat exchange of molten salt in the heating device.

[0074] 3. By arranging heating rods in an alternating pattern, periodic vortex regions are formed, which promotes full mixing of the fluid in the alternating vortex regions, increases turbulence, and thus increases the convective heat transfer coefficient, so that the heat from the heating rods is continuously and rapidly removed.

[0075] 4. The multi-channel feeding structure with vertically arranged feed inlets promotes the movement of molten salt in the first chamber, quickly removes the heat exchange fluid, enhances heat transfer, avoids local high temperature in the heating rod, and improves the temperature uniformity of the flow field.

[0076] 5. Add a buffer device with a radiant heating design for non-contact heat transfer to keep the molten salt in the buffer tank warm.

[0077] Another aspect of the application proposes a method for heating molten salt, comprising the following steps:

[0078] S1, molten salt enters the first heating device 100 through the feed inlet for primary heating; S2, the molten salt after primary heating is pressurized by the jet assembly and injected into the second heating device 200 for secondary heating; S3, the molten salt after secondary heating enters the buffer device 400 for buffering. Through multi-stage heating, the temperature uniformity of the molten salt is improved by gradually increasing the temperature.

[0079] In step S1, molten salt enters the first cavity 110 through the first inlet 130, the second inlet 140, and the third inlet 150. The molten salt forms a vortex region between the heating rods. Subsequently, the molten salt entering through the three inlets propels the molten salt in the vortex region of the first cavity 110 towards the second cavity 220. This multi-channel feeding structure promotes the movement of molten salt within the first cavity, rapidly carrying away the heat exchange fluid, enhancing heat transfer, avoiding localized high temperatures in the heating rods, and improving the temperature uniformity of the flow field.

[0080] Specifically, molten salt flows in through the inlet pipe and then enters the first chamber through the distributor. In the first chamber, the molten salt is initially heated by contact heating with an immersion electric heating rod. After initial heating, the molten salt enters the second chamber through a nozzle to form an impact jet. The molten salt exchanges heat with the immersion electric heating rod in the form of a jet, resulting in a second heating. After the second heating, the molten salt enters the heating buffer chamber through a guide pipe for pre-heating buffering. The molten salt in the buffer tank is then heated again by a radiant electric heating rod to ensure uniform temperature. When the molten salt temperature reaches the target temperature value, the valve is opened, and the molten salt enters the subsequent molten salt heat storage tank.

[0081] The molten salt heating method proposed in this invention achieves the following technical effects:

[0082] 1. Multi-stage heating is adopted to gradually increase the temperature of the molten salt, thereby avoiding local overheating and enhancing the adaptability of the high-voltage electric heating device in the solar power generation system.

[0083] 2. By setting jet components between multi-stage heating devices, molten salt impact jets are formed, which enhances the heat exchange of molten salt in the heating device.

[0084] 3. Molten salt forms a vortex region between the heating rods. Then, the molten salt entering through the vertically distributed feed inlets propels the molten salt in the vortex region of the first chamber toward the second chamber, quickly carrying away the heat exchange fluid, enhancing heat transfer, avoiding local high temperatures in the heating rods, and improving the temperature uniformity of the flow field.

[0085] 4. An additional buffering step is added, employing a radiant heating design for non-contact heat transfer to keep the molten salt in the buffer tank warm.

[0086] Another aspect of the application proposes a photovoltaic-photothermal coupling system. This system uses the aforementioned molten salt heating system and method to convert at least a portion of the abandoned photovoltaic power into thermal energy, which is then stored in the thermal storage system of the solar thermal power plant. This improves the energy utilization rate of the coupling system, solves the problems of heating safety and temperature distribution uniformity of the high-voltage electric heater, and enhances the adaptability of the high-voltage electric heating device in the photovoltaic-photothermal complementary power generation system.

[0087] In summary, the photovoltaic-photothermal coupling system proposed in this embodiment achieves the following technical effects:

[0088] 1. The photovoltaic-photothermal coupling system adopts a molten salt heating system, which improves the uniformity of molten salt temperature, reduces the material and manufacturing costs of the heating device, and enhances the adaptability of the high-voltage electric heating device in the solar power generation system.

[0089] 2. In the photovoltaic-photothermal coupling system, the molten salt heating system forms a periodic vortex region by arranging heating rods in an alternating manner. This promotes the full mixing of the fluid in the alternating vortex region, increases the turbulence, and thus increases the convective heat transfer coefficient, allowing the heat from the heating rods to be continuously and rapidly carried away.

[0090] 3. The molten salt heating system in the photovoltaic-photothermal coupling system adopts a multi-channel feeding structure with vertically arranged feed inlets, which promotes the movement of molten salt in the first cavity, quickly removes the heat exchange fluid, enhances heat transfer, avoids local high temperature of the heating rod, and improves the temperature uniformity of the flow field.

[0091] 4. The molten salt heating system in the photovoltaic-photothermal coupling system is equipped with a buffer device, which adopts a radiation heating design and non-contact heat transfer to keep the molten salt in the buffer tank warm.

[0092] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A molten salt heating system, characterized in that, It includes a first heating device (100), a second heating device (200), and a jet assembly located between the first heating device (100) and the second heating device (200). The molten salt undergoes primary heating in the first heating device (100), moves horizontally towards the second heating device (200), and enters the jet assembly in fluid form for pressurization, then is injected into the second heating device (200) for secondary heating to reach the target heating temperature; The first heating device (100) includes a first cavity (110) and a heating assembly located inside the first cavity (110). The heating assembly includes a first group of heating rods and a second group of heating rods distributed along both sides of the axial direction of the first cavity (110). The first group of heating rods and the second group of heating rods form an interlaced vortex region. The first group of heating rods and the second group of heating rods each include a plurality of first heating rods (122) and a plurality of second heating rods (124) periodically distributed along the axial direction of the first cavity (110). The first heating rods (122) and the second heating rods (124) are arranged in parallel and staggered. A first vortex region is formed between adjacent first heating rods (122), and a second vortex region is formed between adjacent second heating rods (124). The first heating device (100) further includes a first feed port (130), which is connected to the first vortex region. The molten salt enters the first cavity (110) through the first feed port (130) and propels the molten salt in the first vortex region toward the axis close to the first cavity (110). The first heating device (100) further includes a second feed port (140), which is connected to the second vortex region and propels the molten salt in the second vortex region toward the axis close to the first cavity (110).

2. The molten salt heating system according to claim 1, characterized in that, The first heating device (100) further includes a third feed port (150), which is aligned with the axis of the first cavity (110). The molten salt enters the first cavity (110) through the third feed port (150) and moves the molten salt in the propulsion axis region toward the second heating device (200).

3. The molten salt heating system according to claim 2, characterized in that, The cross-sectional area of ​​the third feed inlet (150) is greater than that of the first feed inlet (130) and the second feed inlet (140).

4. The molten salt heating system according to claim 2 or 3, characterized in that, The cross-sectional area of ​​the first feed port (130), the second feed port (140) and the third feed port (150) increases along the direction of molten salt entry.

5. The molten salt heating system according to claim 2 or 3, characterized in that, The first heating device (100) further includes a distributor (160) which is connected to the first feed port (130), the second feed port (140) and the third feed port (150).

6. The molten salt heating system according to any one of claims 1-3, characterized in that, The second heating device (200) includes a second cavity (220) and a third heating rod (222) located inside the second cavity (220). The molten salt is injected toward the third heating rod (222) to form an impact jet on the surface of the third heating rod (222).

7. The molten salt heating system according to claim 6, characterized in that, The jet assembly includes a spacer (310) between the first cavity (110) and the second cavity (220) and a nozzle (320) located on the spacer (310).

8. The molten salt heating system according to any one of claims 1-3, characterized in that, It also includes a buffer device (400), into which the molten salt after secondary heating is stored.

9. The molten salt heating system according to claim 8, characterized in that, The buffer device (400) includes a heated buffer cavity (420), a plurality of buffer tanks (422) located in the central area of ​​the heated buffer cavity (420), and a fourth heating rod (424) near the inner wall of the heated buffer cavity (420), the fourth heating rod (424) radiating heat to the buffer tanks (422).

10. The molten salt heating system according to claim 9, characterized in that, The buffer device (400) also includes a distributor (426) through which the molten salt enters a plurality of the buffer tanks (422).

11. The molten salt heating system according to claim 10, characterized in that, The buffer device (400) also includes a dispensing tube (428) that connects the distributor (426) and the buffer tank (422).

12. A molten salt heating method, employing the molten salt heating system according to any one of claims 1-11, characterized in that, Includes the following steps, S1, molten salt enters the first heating device (100) through the feed inlet for primary heating; S2, the molten salt after primary heating is pressurized by the jet assembly and injected into the second heating device (200) for secondary heating; S3, the molten salt, after secondary heating, enters the buffer device (400) for buffering.

13. The molten salt heating method according to claim 12, characterized in that, In step S1, the molten salt is heated in the staggered vortex region formed in the first cavity (110), and then the molten salt entering the first cavity (110) through the first feed port (130), the second feed port (140) and the third feed port (150) moves the molten salt in the vortex region toward the second cavity (220).

14. A photovoltaic-photothermal coupling system, characterized in that, The system includes the molten salt heating system according to any one of claims 1-11, which is used to convert at least a portion of the abandoned photovoltaic power into thermal energy and store it in the thermal storage system of the solar thermal power plant.

Images