Fused salt heating device and control method thereof, energy storage system

Abstract

The application provides a molten salt heating device, a control method thereof and an energy storage system, wherein the molten salt heating device comprises: a first storage tank with a first outlet; a first liquid collector arranged in communication with the first outlet; a heating structure with a first flow passage and a second flow passage arranged at intervals, the first flow passage has a first flow inlet in communication with the first liquid collector, the second flow passage has a second flow inlet in communication with the first liquid collector, in the height direction of the first liquid collector, the distance between the first flow inlet and a molten salt inlet is greater than the distance between the second flow inlet and the molten salt inlet; a first end of a first electrically conductive part can be in electrically conductive cooperation with the molten salt; a first end of a second electrically conductive part can be in electrically conductive cooperation with the molten salt; an air pipe is in communication with the first liquid collector; and a pressure regulating valve is arranged on the air pipe. The technical scheme of the application effectively solves the problem of difficult power regulation of the molten salt heater in the related art.

Description

Technical Field

[0001] This invention relates to the field of molten salt heating equipment technology, and more specifically, to a molten salt heating device and its control method and energy storage system. Background Technology

[0002] Currently, the installed capacity of clean energy in the power system has increased significantly. However, clean energy is characterized by fluctuations and intermittency, posing a threat to the security of existing power systems. Electrically heated molten salt thermal storage technology can be used to store the electrical energy generated from clean energy sources. When applying this technology, a molten salt heater can be used. The molten salt heater includes a molten salt pump and an injection pipe with multiple injection ports.

[0003] In related technologies, by adjusting the molten salt pump, molten salt can be ejected from different nozzles, thereby changing the contact length between the molten salt and the electrode plate, and thus achieving power regulation. However, the power of the molten salt pump cannot be precisely adjusted, making power control of the molten salt heater quite difficult. Summary of the Invention

[0004] The main objective of this invention is to provide a molten salt heating device and its control method, as well as an energy storage system, to solve the problem of power regulation difficulties in molten salt heaters in related technologies.

[0005] To achieve the above objectives, according to a first aspect of the present invention, a molten salt heating device is provided, comprising: a first storage tank storing molten salt and having a first outlet; a first collector having a molten salt inlet communicating with the first outlet to allow molten salt in the first storage tank to flow into the first collector; a heating structure having a first flow channel and a second flow channel spaced apart, the first flow channel having a first flow inlet communicating with the first collector, and the second flow channel having a second flow inlet communicating with the first collector, wherein the distance between the first flow inlet and the molten salt inlet in the height direction of the first collector is greater than the distance between the second flow inlet and the molten salt inlet; a first conductive element having a first end disposed between the first outlet and the molten salt inlet and capable of conductively engaging with the molten salt, and a second end of the first conductive element being a first conductive connection end; a second conductive element having a first end disposed downstream of the heating structure and capable of conductively engaging with the molten salt, and a second end of the second conductive element being a second conductive connection end; a gas pipe communicating with the first collector; and a pressure regulating valve disposed on the gas pipe.

[0006] Furthermore, a gas inlet is provided on the first liquid collector, and a gas pipe is connected to the gas inlet. In the height direction of the first liquid collector, the gas inlet is higher than the second flow inlet.

[0007] Furthermore, a first buffer cavity is provided inside the first liquid collector, and the cavity wall of the first buffer cavity is a first concave spherical surface.

[0008] Furthermore, the first flow channel has a first flow outlet, the second flow channel has a second flow outlet, and the molten salt heating device also includes a second storage tank. The second storage tank is connected to both the first flow outlet and the second flow outlet, and the first end of the second conductive element is disposed between the heating structure and the second storage tank.

[0009] Furthermore, the molten salt heating device also includes a first connecting pipe and a delivery pump. The first connecting pipe connects the first outlet and the molten salt inlet. The delivery pump is installed on the first connecting pipe and has a delivery state and a shutdown state. The first conductive element is installed inside the first connecting pipe.

[0010] Furthermore, in the height direction of the first liquid collector, the first storage tank is located above the second storage tank.

[0011] Furthermore, the molten salt heating device also includes a second liquid collector, which is disposed between the first overflow outlet and the second storage tank, and is also disposed between the second overflow outlet and the second storage tank. The second liquid collector is provided with a second buffer chamber, the wall of which is a second concave spherical surface. The first end of the second conductive element is disposed between the second liquid collector and the second storage tank.

[0012] Furthermore, the molten salt heating device also includes a second connecting pipe, which connects the second liquid collector and the second storage tank, and a second conductive element is disposed inside the second connecting pipe.

[0013] Furthermore, the heating structure includes a first insulated spiral tube and a second insulated spiral tube, with the inner wall of the first insulated spiral tube forming a first flow channel and the inner wall of the second insulated spiral tube forming a second flow channel.

[0014] Furthermore, a plane perpendicular to the axis of the first insulating spiral tube is set as a preset plane, the axis of the first insulating spiral tube is set parallel to the axis of the second insulating spiral tube, the area enclosed by the projection of the first insulating spiral tube on the preset plane is the first region, the area enclosed by the projection of the second insulating spiral tube on the preset plane is the second region, and the diameter of the first region is smaller than the diameter of the second region.

[0015] Furthermore, the axes of the first insulating spiral tube and / or the second insulating spiral tube are arranged parallel to the height direction of the first liquid collector.

[0016] Furthermore, the molten salt heating device also includes a gas tank, with a gas pipe positioned between the gas tank and the first liquid collector.

[0017] Furthermore, the molten salt heating device also includes a liquid level detection element disposed within the first liquid collector, and / or, the molten salt heating device also includes a pressure detection element disposed within the first liquid collector.

[0018] Furthermore, the molten salt heating device also includes a power source, and the second ends of the first conductive element and the second conductive element are both electrically connected to the power source. And / or, the molten salt heating device also includes a control unit, which is coordinated with the pressure regulating valve.

[0019] According to a second aspect of the present invention, an energy storage system is provided, comprising an energy delivery system and a molten salt heating device, wherein the molten salt heating device is the aforementioned molten salt heating device, and the energy delivery system is electrically connected to a first conductive element and a second conductive element of the molten salt heating device.

[0020] According to a third aspect of the present invention, a control method for a molten salt heating device is provided for controlling the aforementioned molten salt heating device. The control method includes: when the molten salt heating device is in a first operating state, molten salt in a first storage tank of the molten salt heating device can flow to a first collector of the molten salt heating device; the opening of a pressure regulating valve of the molten salt heating device is adjusted to regulate the liquid level of the molten salt in the first collector, so that the molten salt in the first collector enters the first flow inlet of the heating structure of the molten salt heating device or enters the first flow inlet and the second flow inlet of the heating structure, and the molten salt in the heating structure is heated through a first conductive element and a second conductive element of the molten salt heating device; when the molten salt heating device is in a second operating state, the first storage tank is disconnected from the first collector, and the pressure regulating valve is opened to allow the molten salt in the first collector to flow out through the heating structure.

[0021] According to the technical solution of this invention, the molten salt heating device includes a first storage tank, a first collector, a heating structure, a first conductive element, a second conductive element, a gas pipe, and a pressure regulating valve. Molten salt in the first storage tank can flow to the molten salt inlet through the first outlet, and then flow into the first collector through the molten salt inlet. Molten salt in the first collector can enter the first flow channel through the first flow inlet, or it can enter the second flow channel through the second flow inlet. In the height direction of the first collector, the distance between the first flow inlet and the molten salt inlet is greater than the distance between the second flow inlet and the molten salt inlet; that is, the first flow inlet is located below the second flow inlet. This allows the molten salt level in the first collector to gradually rise after entering, and then the molten salt first flows into the first flow channel through the first flow inlet, and then flows into the second flow channel through the second flow inlet. Under the action of the first and second conductive components, the molten salt is heated as it flows through the first collector and the heating structure, thereby converting the electrical energy transmitted by the energy transmission system into thermal energy stored in the molten salt. By adjusting the opening of the pressure regulating valve, when the pressure inside the first collector increases, the flow rate of the molten salt inside the first collector increases, allowing the molten salt to flow out of the first collector more quickly. This results in the flow rate of the molten salt flowing into the first collector being less than the flow rate of the molten salt flowing out of the first collector, thus lowering the liquid level of the molten salt in the first collector. When the liquid level of the molten salt in the first collector is between the first and second flow inlets, the first flow channel participates in the heating of the molten salt, while the second flow channel does not. This increases the total resistance of the heated molten salt, thereby reducing the power consumption of the molten salt heating device. When the pressure inside the first collector decreases, the flow rate of the molten salt inside the first collector decreases, allowing the molten salt to flow out more slowly. This results in the flow rate of molten salt flowing into the first collector being greater than the flow rate out, thus raising the molten salt level inside the first collector. When the molten salt level in the first collector is higher than the second flow inlet, both the first and second flow channels participate in heating the molten salt. This reduces the total resistance of the heated molten salt, thereby increasing the power of the molten salt heating device. In other words, this application uses a pressure regulating valve and a gas pipe to change the pressure inside the first collector, thereby lowering or raising the molten salt level. This changes whether the second flow channel participates in molten salt heating, thus altering the total resistance of the heated molten salt and achieving power regulation. Adjusting the opening of the pressure regulating valve is easier and more precise than adjusting the power of a molten salt pump, making power regulation easier. Therefore, the technical solution of this application effectively solves the problem of power regulation difficulties in molten salt heaters in related technologies. Attached Figure Description

[0022] The accompanying drawings, which form part of this application, 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:

[0023] Figure 1 A schematic diagram of an embodiment of the molten salt heating device according to the present invention is shown;

[0024] Figure 2 It shows Figure 1 A cross-sectional schematic diagram of the first connecting pipe and the first conductive component of the molten salt heating device;

[0025] Figure 3 It shows Figure 1 A cross-sectional schematic diagram of the second connecting pipe and the second conductive component of the molten salt heating device;

[0026] Figure 4 A schematic diagram illustrating the steps of an embodiment of a control method for a molten salt heating apparatus according to the present invention is shown.

[0027] The above figures include the following reference numerals:

[0028] 10. First storage tank; 20. First liquid collector; 30. Heating structure; 31. First insulated spiral tube; 32. Second insulated spiral tube; 40. First conductive element; 50. Second conductive element; 60. Gas pipe; 70. Pressure regulating valve; 80. Second storage tank; 90. First connecting pipe; 100. Transfer pump; 110. Second liquid collector; 120. Second connecting pipe; 130. Gas tank; 140. Liquid level detection element; 150. Pressure detection element; 160. Power supply. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0031] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0032] like Figures 1 to 3 As shown, the molten salt heating device of this embodiment includes: a first storage tank 10, a first collector 20, a heating structure 30, a first conductive element 40, a second conductive element 50, a gas pipe 60, and a pressure regulating valve 70. The first storage tank 10 stores molten salt and has a first outlet. The first collector 20 has a molten salt inlet, which is connected to the first outlet, allowing the molten salt in the first storage tank 10 to flow into the first collector 20. The heating structure 30 has a first flow channel and a second flow channel spaced apart. The first flow channel has a first flow inlet connected to the first collector 20, and the second flow channel has a second flow inlet connected to the first collector 20. In the height direction of the first collector 20, the distance between the first flow inlet and the molten salt inlet is greater than the distance between the second flow inlet and the molten salt inlet. The first end of the first conductive element 40 is disposed between the first outlet and the molten salt inlet and can conduct electricity with the molten salt. The second end of the first conductive element 40 is a first conductive connection end. The first end of the second conductive element 50 is located downstream of the heating structure 30 and can conduct electricity with the molten salt. The second end of the second conductive element 50 is a second conductive connection end. The gas pipe 60 is connected to the first liquid collector 20. The pressure regulating valve 70 is installed on the gas pipe 60.

[0033] Applying the technical solution of this embodiment, the molten salt heating device includes a first storage tank 10, a first collector 20, a heating structure 30, a first conductive element 40, a second conductive element 50, a gas pipe 60, and a pressure regulating valve 70. Molten salt in the first storage tank 10 can flow to the molten salt inlet through the first outlet, and then flow into the first collector 20 through the molten salt inlet. Molten salt in the first collector 20 can enter the first flow channel through the first flow inlet, or it can enter the second flow channel through the second flow inlet. In the height direction of the first collector 20, the distance between the first flow inlet and the molten salt inlet is greater than the distance between the second flow inlet and the molten salt inlet; that is, the first flow inlet is located below the second flow inlet. This allows the molten salt level in the first collector 20 to gradually rise after entering, and the molten salt first flows into the first flow channel through the first flow inlet, and then flows into the second flow channel through the second flow inlet. Under the action of the first conductive element 40 and the second conductive element 50, the molten salt is heated as it flows through the first collector 20 and the heating structure 30, thereby converting the electrical energy transmitted by the energy transmission system into thermal energy stored in the molten salt. By adjusting the opening of the pressure regulating valve 70, when the pressure inside the first collector 20 increases, the flow rate of the molten salt inside the first collector 20 increases, allowing the molten salt to flow out of the first collector 20 more quickly. This results in the flow rate of the molten salt flowing into the first collector 20 being less than the flow rate of the molten salt flowing out of the first collector 20, thus lowering the liquid level of the molten salt inside the first collector 20. When the liquid level of the molten salt inside the first collector 20 is between the first and second flow inlets, the first flow channel participates in the heating of the molten salt, while the second flow channel does not. This increases the total resistance of the heated molten salt, thereby reducing the power of the molten salt heating device. When the pressure inside the first collector 20 decreases, the flow rate of the molten salt inside the first collector 20 decreases, allowing the molten salt to flow out more slowly. This results in the flow rate of molten salt flowing into the first collector 20 being greater than the flow rate out of the first collector 20, thus raising the liquid level of the molten salt inside the first collector 20. When the liquid level of the molten salt inside the first collector 20 is higher than the second flow inlet, both the first and second flow channels participate in the heating of the molten salt. This reduces the total resistance of the heated molten salt, thereby increasing the power of the molten salt heating device. In other words, this application uses a pressure regulating valve 70 and an air pipe 60 to change the pressure inside the first collector 20, thereby lowering or raising the liquid level of the molten salt inside the first collector 20. This changes whether the second flow channel participates in the heating of the molten salt, thus altering the total resistance of the heated molten salt and achieving power regulation. The opening of the pressure regulating valve 70 is easier and more precise to adjust than the power adjustment of the molten salt pump, which in turn makes power adjustment easier.Therefore, the technical solution of this embodiment effectively solves the problem of power regulation difficulties in molten salt heaters in related technologies.

[0034] It should be noted that the gas is nitrogen, but of course, other gases can also be used.

[0035] Specifically, the pressure regulating valve 70 can be a pressure reducing valve.

[0036] It should be noted that the molten salt heating device also includes a flow guide, which is disposed within and connected to the first liquid collector 20. The flow guide is located below the molten salt inlet. This arrangement reduces the splashing of molten salt within the first liquid collector 20 when it enters the first liquid collector 20.

[0037] The flow guide includes a flow guide cone, the tapered part of which is positioned towards the molten salt inlet; that is, the cross-sectional area of ​​the flow guide cone gradually increases from top to bottom. Alternatively, the outer surface of the tip of the flow guide cone can be hemispherical to reduce molten salt splashing when it comes into contact with the flow guide cone.

[0038] like Figure 1 As shown, in this embodiment, a gas inlet is provided on the first liquid collector 20, and the gas pipe 60 is connected to the gas inlet. In the height direction of the first liquid collector 20, the gas inlet is higher than the second flow inlet. With the above arrangement, compared to the gas inlet being lower than the second flow inlet, the technical solution of this embodiment allows the gas in the first liquid collector 20 to more effectively apply pressure to the molten salt in the first liquid collector 20 when the opening of the pressure regulating valve 70 is increased, so that the molten salt in the first liquid collector 20 can flow out more quickly. This allows the liquid level of the molten salt in the first liquid collector 20 to decrease. When the liquid level of the molten salt in the first liquid collector 20 decreases to between the first flow inlet and the second flow inlet, the first flow channel participates in the heating of the molten salt, while the second flow channel does not participate in the heating of the molten salt. In this way, the total resistance of the heated molten salt increases, thereby reducing the power of the molten salt heating device, that is, reducing the pressure more quickly. When the opening of the pressure regulating valve 70 is reduced, the pressure inside the first collector 20 can be reduced more quickly. This makes the outflow velocity of the molten salt inside the first collector 20 less than the inflow velocity of the molten salt inside the first collector 20. That is, the flow rate of the molten salt flowing into the first collector 20 is greater than the flow rate of the molten salt flowing out of the first collector 20. As a result, the liquid level of the molten salt inside the first collector 20 can be increased. When the liquid level of the molten salt inside the first collector 20 is higher than the second flow inlet, both the first flow channel and the second flow channel participate in the heating of the molten salt. This reduces the total resistance of the heated molten salt, thereby increasing the power of the molten salt heating device.

[0039] It should be noted that both the molten salt inlet and the gas inlet are located on the top surface of the first liquid collector 20, and the top surface of the first liquid collector 20 is a plane.

[0040] like Figure 1 As shown, in this embodiment, a first buffer cavity is provided inside the first liquid collector 20, and the cavity wall of the first buffer cavity is a first concave spherical surface.

[0041] It should be noted that during the transport of molten salt, the first concave spherical surface can reduce the splashing of molten salt and avoid scattering at the end of the molten salt splash column, which would cause salt mist in the first collector 20, leading to electric arc and high-voltage breakdown.

[0042] like Figure 1 As shown, in this embodiment, the first flow channel has a first flow outlet, the second flow channel has a second flow outlet, and the molten salt heating device further includes a second storage tank 80, which is connected to both the first and second flow outlets. Molten salt in the first flow channel, after being heated, can flow through the first flow outlet to the second storage tank 80. Molten salt in the second flow channel, after being heated, can flow through the second flow outlet to the second storage tank 80. That is, the second storage tank 80 can store the heated molten salt, realizing the conversion of electrical energy into thermal energy for storage. The first end of the second conductive element 50 is disposed between the heating structure 30 and the second storage tank 80, so that the molten salt flowing through the heating structure 30 can be sufficiently heated.

[0043] like Figure 1 and Figure 2 As shown, in this embodiment, the molten salt heating device further includes a first connecting pipe 90 and a delivery pump 100. The first connecting pipe 90 connects the first outlet and the molten salt inlet. The delivery pump 100 is disposed on the first connecting pipe 90 and has a delivery state and a shutdown state. The first conductive element 40 is disposed inside the first connecting pipe 90.

[0044] In other embodiments, the transfer pump 100 may be omitted, and the first connecting pipe 90 may be located below the first storage tank 10 and above the first collector 20. In this way, the molten salt can be flowed using the gravitational potential energy of the molten salt, and thus the molten salt can flow to the first collector 20.

[0045] like Figure 1 As shown, in this embodiment, the first storage tank 10 is located above the second storage tank 80 in the height direction of the first liquid collector 20. This results in a smaller distance between the first liquid collector 20 and the first storage tank 10 in the height direction of the first liquid collector 20, which reduces the energy required for transporting the molten salt in the first storage tank 10 to the first liquid collector 20, and also reduces the power loss of the transfer pump 100 when transporting the molten salt in the first storage tank 10.

[0046] It should be noted that, in the height direction of the first liquid collector 20, the first storage tank 10 is located above the first liquid collector 20. Compared to the first storage tank 10 being located below the first liquid collector 20, the technical solution of this embodiment can reduce the electrical energy required to transport molten salt from the first storage tank 10 to the first liquid collector 20. That is, the transfer pump 100 only needs a smaller power to achieve the transport of molten salt, and it can also reduce the loss of the transfer pump 100 when transporting molten salt, thereby improving the energy utilization rate.

[0047] It should be noted that, in the height direction of the first liquid collector 20, the first liquid collector 20 is located above the second liquid collector 110. That is, in the height direction of the first liquid collector 20, the first storage tank 10, the first liquid collector 20, the second liquid collector 110, and the second storage tank 80 are arranged sequentially, resulting in a compact structure, simple operation, and safe and reliable operation. Compared to the first storage tank 10, the first liquid collector 20, the second liquid collector 110, and the second storage tank 80 being arranged at intervals in the horizontal plane, the various structures in this embodiment are arranged in the vertical space, which can reduce the use of horizontal space. Within a certain area of ​​horizontal space, more molten salt heating devices can be arranged, improving space utilization.

[0048] like Figure 1 As shown, in this embodiment, the molten salt heating device further includes a second collector 110. The second collector 110 is disposed between the first outflow outlet and the second storage tank 80, and also between the second outflow outlet and the second storage tank 80. A second buffer chamber is provided within the second collector 110, allowing the molten salt flowing out of the first outflow channel to flow into the second collector 110, and then into the second storage tank 80. The second collector 110 allows the heated molten salt to enter the second storage tank 80 more smoothly, reducing the impact on the second storage tank 80 and thus reducing molten salt splashing. The first end of the second conductive element 50 is disposed between the second collector 110 and the second storage tank 80, ensuring that the molten salt flowing through the heating structure 30 and the second collector 110 is sufficiently heated. The wall of the second buffer chamber is a second concave spherical surface, which allows the molten salt to flow from top to bottom along the wall of the second buffer chamber when it initially enters, reducing the splashing of the molten salt.

[0049] like Figure 1 and Figure 3As shown, in this embodiment, the molten salt heating device further includes a second connecting pipe 120, which connects the second collector 110 and the second storage tank 80. The molten salt in the second collector 110 can flow to the second storage tank 80 through the second connecting pipe 120. A second conductive element 50 is disposed in the second connecting pipe 120, so that the molten salt flowing through the heating structure 30 and the second collector 110 can be sufficiently heated.

[0050] It should be noted that the first connecting pipe 90, the second connecting pipe 120, the first liquid collector 20, the second liquid collector 110, the first insulating spiral tube 31, the second insulating spiral tube 32, the third insulating spiral tube, the first conductive element 40, and the second conductive element 50 are all made of corrosion-resistant materials and will not be damaged during the use of the molten salt heating device. The first liquid collector 20, the second liquid collector 110, the first insulating spiral tube 31, the second insulating spiral tube 32, and the third insulating spiral tube are all made of insulating materials.

[0051] It should be noted that the first conductive element 40 includes a first electrode plate, and the second conductive element 50 includes a second electrode plate. Alternatively, the first conductive element 40 and the second conductive element 50 can also be conductive pillars. Through holes can be provided on the first and second electrode plates, allowing molten salt to flow through them. The first conductive element 40 can be inclined relative to the first connecting pipe 90, and the second conductive element 50 can be inclined relative to the second connecting pipe 120.

[0052] like Figure 1 As shown, in this embodiment, the heating structure 30 includes a first insulating spiral tube 31 and a second insulating spiral tube 32. The inner wall of the first insulating spiral tube 31 forms a first flow channel, and the inner wall of the second insulating spiral tube 32 forms a second flow channel. With the same cross-sectional area, the first insulating spiral tube 31 has a longer tube length than a straight tube. The molten salt inside the first insulating spiral tube 31 can be considered as a cylindrical resistor. According to the resistance formula R = (ρ × l) / (ρ × l) ） / S, where R is the resistance value, ρ is the molten salt density, l is the tube length, and S is the cross-sectional area. When S and ρ are constant, the resistance value of the longer first insulated spiral tube 31 is greater. Therefore, the power of the molten salt heating device can be adjusted to a smaller value, that is, the adjustable lower limit of the power of the molten salt heating device is lower. Compared with a straight tube, the resistance value of the first insulated spiral tube 31 is greater. Therefore, during heating, the current passing through the first insulated spiral tube 31 is lower, which can avoid the phenomenon of excessively high local temperature or too large temperature gradient.

[0053] It should be noted that the heating structure 30 also includes at least one group of flow channels, each group having at least one third flow channel communicating with the first liquid collector 20. Each third flow channel has a third flow inlet, and in the height direction of the first liquid collector 20, the distance between each third flow inlet and the molten salt inlet is greater than the distance between the first flow inlet and the molten salt inlet. By setting up the flow channel group, the power adjustment range of the molten salt heating device can be further improved.

[0054] Multiple flow channel groups are spaced apart along the height of the first liquid collector 20. Each flow channel group has multiple third flow inlets, and the distances between the multiple third flow inlets of each channel group and the molten salt inlet are all equal. By setting multiple flow channel groups, the power adjustment range of the molten salt heating device can be further improved.

[0055] It should be noted that the first liquid collector 20 also has a first molten salt outlet, a second molten salt outlet and at least one third molten salt outlet. The first molten salt outlet is configured to correspond to the first flow channel, the second molten salt outlet is configured to correspond to the second flow channel, and the third molten salt outlet is configured to correspond to the third flow channel.

[0056] The heating structure 30 also includes a third insulating spiral tube, the inner wall of which forms a third flow channel.

[0057] It should be noted that there are multiple first flow channels, which are spaced apart in the circumferential direction of the first liquid collector 20. Specifically, the multiple first flow channels are evenly distributed in the circumferential direction of the first liquid collector 20. There are also multiple second flow channels, which are spaced apart in the circumferential direction of the first liquid collector 20. Specifically, the multiple second flow channels are evenly distributed in the circumferential direction of the first liquid collector 20. Furthermore, multiple third flow channels within a flow channel group are spaced apart in the circumferential direction of the first liquid collector 20. Specifically, the multiple third flow channels are evenly distributed in the circumferential direction of the first liquid collector 20.

[0058] It should be noted that the first, second, and third flow channels are all spiral channels. The inner diameter, length, direction of rotation, and span of each spiral channel are the same. The pitch of the second flow channel is greater than that of the first flow channel. This ensures that the molten salt is heated with the same power in both the first and second flow channels, thus solving the problem of overheating and decomposition of some molten salt and insufficient heating of molten salt caused by excessive differences in heating power.

[0059] In a plurality of flow channel groups, one of two adjacent flow channel groups is designated as the first flow channel group, and the other of two adjacent flow channel groups is designated as the second flow channel group. The first flow channel group is positioned relative to the second flow channel group, closer to the top surface of the first liquid collector 20. The pitch of the third flow channel in the first flow channel group is greater than the pitch of the third flow channel in the first flow channel group.

[0060] like Figure 1 As shown, in this embodiment, a plane perpendicular to the axis of the first insulating spiral tube 31 is defined as a preset plane. The axis of the first insulating spiral tube 31 is parallel to the axis of the second insulating spiral tube 32. The area enclosed by the projection of the first insulating spiral tube 31 onto the preset plane is the first region, and the area enclosed by the projection of the second insulating spiral tube 32 onto the preset plane is the second region. The diameter of the first region is smaller than the diameter of the second region. This facilitates the arrangement of the first insulating spiral tube 31 and the second insulating spiral tube 32 in the height direction of the first liquid collector.

[0061] It should be noted that the axis of the first insulating spiral tube 31 is parallel to the direction from the first liquid collector to the second liquid collector. The centerline of the first insulating spiral tube is a spiral line. The second insulating spiral tube 32 and the third insulating spiral tube are similarly arranged.

[0062] It should be noted that the axis of the first insulating spiral tube 31 is arranged parallel to the axis of the third insulating spiral tube. The area enclosed by the projection of the third insulating spiral tube onto the preset plane is the third region, and the diameter of the third region is smaller than the diameter of the first region. This facilitates the arrangement of the first insulating spiral tube 31 and the third insulating spiral tube in the height direction of the first liquid collector.

[0063] In other embodiments, the heating structure 30 can be a heating column, and the first flow channel, the second flow channel and the third flow channel are all disposed inside the heating column.

[0064] like Figure 1 As shown, in this embodiment, the axes of the first insulating spiral tube 31 and the second insulating spiral tube 32 are arranged parallel to the height direction of the first liquid collector 20. This allows the molten salt to flow within the first insulating spiral tube 31 and the second insulating spiral tube 32 under its own weight.

[0065] like Figure 1 As shown, in this embodiment, the molten salt heating device further includes a gas tank 130, and a gas pipe 60 is disposed between the gas tank 130 and the first liquid collector 20. Through the cooperation of the gas tank 130, the gas pipe 60, and the pressure regulating valve 70, the pressure inside the first liquid collector 20 can be reduced or increased, thereby increasing or decreasing the liquid level of the molten salt inside the first liquid collector 20, and thus the power of the molten salt heating device can be adjusted.

[0066] like Figure 1 As shown, in this embodiment, the molten salt heating device further includes a liquid level detection element 140, which is disposed within the first liquid collector 20. The liquid level detection element 140 can detect the liquid level within the first liquid collector 20.

[0067] It should be noted that the liquid level detection device can be a liquid level gauge.

[0068] like Figure 1 As shown, in this embodiment, the molten salt heating device further includes a pressure detection element 150, which is disposed inside the first liquid collector 20. The pressure detection element 150 can detect the pressure inside the first liquid collector 20, ensuring that the pressure inside the first liquid collector 20 remains within a reasonable range. When the pressure inside the first liquid collector 20 exceeds the reasonable range, an alarm will be triggered to alert the operator.

[0069] It should be noted that the pressure detection device can be a pressure gauge. The alarm device can be a warning light.

[0070] like Figure 1 As shown, in this embodiment, the molten salt heating device further includes a power supply 160, and the second ends of the first conductive element 40 and the second conductive element 50 are both electrically connected to the power supply 160. Through the above configuration, the power supply 160 can apply voltage to the first conductive element 40 and the second conductive element 50, so that when the molten salt flows, a current is generated between the power supply 160, the first conductive element 40, the second conductive element 50, and the molten salt, thereby heating the molten salt.

[0071] It should be noted that during the use of the molten salt heating device, the voltage between the first conductive element 40 and the second conductive element 50 remains constant, that is, the voltage of the power supply 160 remains constant.

[0072] Specifically, the molten salt heating device also includes a first wire and a second wire. The first wire is connected between the power supply 160 and the second end of the first conductive element 40, and the second wire is connected between the power supply 160 and the second end of the second conductive element 50.

[0073] like Figure 1 As shown, in this embodiment, the molten salt heating device further includes a control unit, which works in conjunction with the pressure regulating valve 70. The control unit can control the opening degree of the pressure regulating valve 70.

[0074] It should be noted that the control unit works in conjunction with the delivery pump 100.

[0075] In this embodiment, the molten salt heating device uses a transfer pump 100 to transport molten salt from the first storage tank 10 to the first collector 20. The molten salt enters the first collector 20 through the molten salt inlet. The molten salt in the first collector 20 can flow into the first flow channel but not into the second flow channel, or it can flow into both the first and second flow channels simultaneously. The molten salt in the first flow channel can flow through the second collector 110 to the second storage tank 80, and the molten salt in the second flow channel can also flow through the second collector 110 to the second storage tank 80. When the molten salt flows sequentially through the first connecting pipe 90, the first liquid collector 20, the first flow channel, and the second liquid collector 110, it can be heated under the action of the power supply 160, the first conductive element 40, and the second conductive element 50.

[0076] When molten salt flows into the first flow channel but not into the second flow channel, the total resistance of the heated molten salt is the first resistance. When molten salt flows into both the first and second flow channels simultaneously, the total resistance of the heated molten salt is the second resistance. The first resistance is greater than the second resistance; that is, the first resistance and the second resistance are different.

[0077] Specifically, when molten salt flows into the first collector 20, if the flow rate of molten salt into the first collector 20 is greater than the flow rate of molten salt out of the first collector 20, the liquid level in the first collector 20 gradually rises. Then, from bottom to top, the molten salt gradually submerges the third inlet of each flow channel group. When the molten salt submerges the third inlet of the highest flow channel group, the liquid level in the first collector 20 gradually rises to the position of the first flow inlet, and then gradually rises to the position of the second flow inlet. During the gradual rise of the liquid level in the first collector 20, the number of flow channels through which molten salt flows gradually increases, thereby gradually reducing the total resistance of the heated molten salt. With a constant voltage, the power gradually increases. That is, the power of the molten salt heating device is adjusted by changing the number of parallel flow channels.

[0078] When molten salt flows into the first liquid collector 20, if the flow rate of molten salt into the first liquid collector 20 is less than the flow rate of molten salt out of the first liquid collector 20, the liquid level in the first liquid collector 20 gradually decreases, causing the number of flow channels through which molten salt flows to gradually decrease. Consequently, the total resistance of the heated molten salt gradually increases, and the power gradually decreases when the voltage remains constant. That is, the power of the molten salt heating device is adjusted by changing the number of parallel flow channels.

[0079] It should be noted that the flow channel in the flow channel through which molten salt flows can be the first flow channel, the second flow channel, or the third flow channel, and not just the first flow channel, the second flow channel, or the third flow channel.

[0080] Specifically, when the molten salt heating device is in use, the delivery pump 100 delivers molten salt from the first storage tank 10 to the first collector 20. The molten salt enters the first collector 20 through the molten salt inlet. At this time, the pressure regulating valve 70 maintains a certain opening. During the flow process, the molten salt is heated by the first conductive element 40 and the second conductive element 50, causing the temperature of the molten salt to rise. The heated molten salt enters the second collector 110 for mixing and finally flows into the second storage tank 80. When it is necessary to adjust the power of the molten salt heating device, the opening of the pressure regulating valve 70 can be changed. This change in the air pressure within the first collector 20 alters the liquid level of the molten salt in the first collector 20, thereby adjusting the number of parallel spiral channels and thus the power. After the molten salt heating device finishes operating, the delivery pump 100 is turned off. At this time, the molten salt remaining in the first liquid collector 20, the first flow channel, the second flow channel, the third flow channel, and the second liquid collector 110 flows to the second storage tank 80 under its own weight and the purging action of the gas. Then the pressure regulating valve 70 is turned off.

[0081] The energy storage system of this embodiment includes an energy delivery system and a molten salt heating device. The molten salt heating device is the one described above. The energy delivery system is electrically connected to the first conductive element 40 and the second conductive element 50 of the molten salt heating device. The molten salt heating device, by setting a pressure regulating valve 70 and a gas pipe 60, changes the pressure within the first liquid collector 20, thereby lowering or raising the liquid level of the molten salt within the first liquid collector 20. This allows the second flow channel to participate in molten salt heating, thus changing the total resistance of the heated molten salt and achieving power regulation. Adjusting the opening of the pressure regulating valve 70 is easier and more precise than power regulation using a molten salt pump, making power regulation easier. The energy storage system with the aforementioned molten salt heating device also possesses these advantages.

[0082] like Figure 4 As shown, the control method for the molten salt heating device in this embodiment is used to control the aforementioned molten salt heating device. The control method includes:

[0083] When the molten salt heating device is in the first working state, the molten salt in the first storage tank 10 can flow to the first liquid collector 20. The opening of the pressure regulating valve 70 is adjusted to regulate the liquid level of the molten salt in the first liquid collector 20, so that the molten salt in the first liquid collector 20 enters the first flow inlet of the heating structure 30 or enters the first flow inlet and the second flow inlet of the heating structure 30, and heats the molten salt in the heating structure 30 through the first conductive element 40 and the second conductive element 50.

[0084] When the molten salt heating device is in the second working state, the first storage tank 10 is disconnected from the first liquid collector 20, and the pressure regulating valve 70 is opened to allow the molten salt in the first liquid collector 20 to flow out from the heating structure 30.

[0085] With the above configuration, when the molten salt heating device is in the first working state, the molten salt in the first storage tank 10 can flow to the first collector 20, and then the molten salt can flow from the first collector 20 to the heating structure 30 and out through the heating structure 30, thus achieving the heating of the molten salt. When the molten salt heating device is in the second working state, the molten salt in the first storage tank 10 will not flow into the first collector 20. This allows the molten salt in the first collector 20 to flow out through the heating structure 30 under the action of the gas pressure when the pressure regulating valve 70 is opened, preventing molten salt from remaining in the first collector 20. At the same time, the molten salt in the heating structure 30 can also flow out.

[0086] It should be noted that the conveying pump 100 has a first conveying state, a second conveying state, a third conveying state, and a shutdown state. When the conveying pump 100 is in the first conveying state, the power of the conveying pump 100 gradually increases. When the conveying pump 100 is in the second conveying state, the power of the conveying pump 100 gradually decreases. When the conveying pump 100 is in the third conveying state, the power of the conveying pump 100 remains unchanged. When the conveying pump 100 is in the shutdown state, the conveying pump 100 stops running.

[0087] The pressure regulating valve 70 has a first regulating state, a second regulating state, a third regulating state, and a closed state. When the pressure regulating valve 70 is in the first regulating state, the opening degree of the pressure regulating valve 70 gradually increases. When the pressure regulating valve 70 is in the second regulating state, the opening degree of the pressure regulating valve 70 gradually decreases. When the pressure regulating valve 70 is in the third regulating state, the opening degree of the pressure regulating valve 70 remains unchanged. When the pressure regulating valve 70 is in the closed state, the pressure regulating valve 70 is closed.

[0088] Specifically, when the molten salt heating device is in its first operating state, the delivery pump 100 is in its first delivery state, and the pressure regulating valve 70 is in its third or fourth regulating state, causing the molten salt level in the first collector 20 to gradually rise. When the molten salt heating device is in its first operating state, the delivery pump 100 is in its second delivery state, and the pressure regulating valve 70 is in its third or fourth regulating state, causing the molten salt level in the first collector 20 to gradually decrease. When the molten salt heating device is in its first operating state, the delivery pump 100 is in its third delivery state, and the pressure regulating valve 70 is in its first regulating state, causing the molten salt level in the first collector 20 to gradually decrease. When the molten salt heating device is in its first operating state, the delivery pump 100 is in its third delivery state, and the pressure regulating valve 70 is in its second delivery state, causing the molten salt level in the first collector 20 to gradually rise. When the molten salt heating device is in its first operating state, the delivery pump 100 is in its third delivery state, and the pressure regulating valve 70 is in its third or fourth regulating state, the liquid level of the molten salt in the first collector 20 remains unchanged. That is, by changing the delivery state of the delivery pump 100 and the regulating state of the pressure regulating valve 70, the power of the molten salt delivery device can be changed.

[0089] When the molten salt heating device is in the second working state, the delivery pump 100 is in the off state, and the pressure regulating valve 70 is in the first regulating state, the second regulating state, or the third regulating state. Under the pressure of the gas, the residual molten salt in the first liquid collector 20, the heating structure 30, and the second liquid collector 110 can be blown into the second storage tank 80 to avoid damage to the molten salt heating device caused by incomplete salt removal.

[0090] In the description of this invention, it should be understood that "a plurality of" means two or more. Directional terms such as "front, back, up, down, left, right," "horizontal, vertical, perpendicular, horizontal," and "top, bottom" indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. These terms are used solely for the convenience of describing the invention and simplifying the description. Unless otherwise stated, these directional terms 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 limiting the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner or outer contours relative to the outline of each component itself.

[0091] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0092] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0093] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. In particular, unless there is a clear contradiction or logical conflict in the context, any technical feature in any embodiment disclosed in this specification can be arbitrarily combined with other technical features in any one or more other embodiments to form a new technical solution. All possible variations formed by combining different features, which can be conceived by those skilled in the art based on the technical teachings provided by the present invention, should be considered as fully disclosed in this specification, and these combinations also fall within the scope of protection claimed by the present invention.

Claims

1. A molten salt heating device, characterized in that, include: A first storage tank (10) contains molten salt and has a first outlet; The first liquid collector (20) has a molten salt inlet, which is connected to the first outlet so that the molten salt in the first storage tank (10) can flow into the first liquid collector (20); The heating structure (30) has a first flow channel and a second flow channel arranged at intervals. The first flow channel has a first flow inlet communicating with the first liquid collector (20). The second flow channel has a second flow inlet communicating with the first liquid collector (20). In the height direction of the first liquid collector (20), the distance between the first flow inlet and the molten salt inlet is greater than the distance between the second flow inlet and the molten salt inlet. The first conductive element (40) has a first end disposed between the first outlet and the molten salt inlet and is capable of conducting electricity with the molten salt. The second end of the first conductive element (40) is a first conductive connection end. The second conductive element (50) has a first end disposed downstream of the heating structure (30) and capable of conducting electricity with the molten salt, and a second end of the second conductive element (50) is a second conductive connection end. The trachea (60) is connected to the first liquid collector (20); A pressure regulating valve (70) is provided on the air pipe (60).

2. The molten salt heating device according to claim 1, characterized in that, The first liquid collector (20) is provided with a gas inlet, and the gas pipe (60) is connected to the gas inlet. In the height direction of the first liquid collector (20), the gas inlet is higher than the second flow inlet.

3. The molten salt heating device according to claim 1, characterized in that, The first liquid collector (20) is provided with a first buffer cavity, and the cavity wall of the first buffer cavity is a first concave spherical surface.

4. The molten salt heating device according to claim 1, characterized in that, The first flow channel has a first flow outlet, the second flow channel has a second flow outlet, the molten salt heating device further includes a second storage tank (80), the second storage tank (80) is connected to both the first flow outlet and the second flow outlet, and the first end of the second conductive element (50) is disposed between the heating structure (30) and the second storage tank (80).

5. The molten salt heating device according to claim 4, characterized in that, The molten salt heating device further includes a first connecting pipe (90) and a delivery pump (100). The first connecting pipe (90) connects the first outlet and the molten salt inlet. The delivery pump (100) is installed on the first connecting pipe (90) and has a delivery state and a shutdown state. The first conductive element (40) is installed inside the first connecting pipe (90).

6. The molten salt heating device according to claim 5, characterized in that, In the height direction of the first liquid collector (20), the first storage tank (10) is located above the second storage tank (80).

7. The molten salt heating device according to claim 4, characterized in that, The molten salt heating device further includes a second liquid collector (110), which is disposed between the first overflow outlet and the second storage tank (80). The second liquid collector (110) is disposed between the second overflow outlet and the second storage tank (80). A second buffer cavity is provided inside the second liquid collector (110), and the cavity wall of the second buffer cavity is a second concave spherical surface. The first end of the second conductive element (50) is disposed between the second liquid collector (110) and the second storage tank (80).

8. The molten salt heating device according to claim 7, characterized in that, The molten salt heating device further includes a second connecting pipe (120), which connects the second liquid collector (110) and the second storage tank (80), and the second conductive element (50) is disposed inside the second connecting pipe (120).

9. The molten salt heating apparatus according to any one of claims 1 to 8, characterized in that, The heating structure (30) includes a first insulating spiral tube (31) and a second insulating spiral tube (32). The inner wall of the first insulating spiral tube (31) forms the first flow channel, and the inner wall of the second insulating spiral tube (32) forms the second flow channel.

10. The molten salt heating device according to claim 9, characterized in that, A plane perpendicular to the axis of the first insulating spiral tube (31) is set as a preset plane. The axis of the first insulating spiral tube (31) is set parallel to the axis of the second insulating spiral tube (32). The area enclosed by the projection of the first insulating spiral tube (31) on the preset plane is a first area. The area enclosed by the projection of the second insulating spiral tube (32) on the preset plane is a second area. The diameter of the first area is smaller than the diameter of the second area.

11. The molten salt heating device according to claim 9, characterized in that, The axes of the first insulating spiral tube (31) and / or the second insulating spiral tube (32) are arranged parallel to the height direction of the first liquid collector (20).

12. The molten salt heating apparatus according to any one of claims 1 to 8, characterized in that, The molten salt heating device also includes a gas tank (130), and the gas pipe (60) is disposed between the gas tank (130) and the first liquid collector (20).

13. The molten salt heating apparatus according to any one of claims 1 to 8, characterized in that, The molten salt heating device further includes a liquid level detection element (140) disposed in the first liquid collector (20), and / or, the molten salt heating device further includes a pressure detection element (150) disposed in the first liquid collector (20).

14. The molten salt heating apparatus according to any one of claims 1 to 8, characterized in that, The molten salt heating device further includes a power supply (160), the second end of the first conductive element (40) and the second end of the second conductive element (50) are both electrically connected to the power supply (160), and / or, the molten salt heating device further includes a control unit, which cooperates with the pressure regulating valve (70) for control.

15. An energy storage system, comprising an energy delivery system and a molten salt heating device, characterized in that, The molten salt heating device is the molten salt heating device according to any one of claims 1 to 14, and the energy transmission system is electrically connected to the first conductive element (40) and the second conductive element (50) of the molten salt heating device.

16. A control method for a molten salt heating device, characterized in that, The control method for controlling the molten salt heating apparatus according to any one of claims 1 to 14 includes: When the molten salt heating device is in the first working state, the molten salt in the first storage tank (10) of the molten salt heating device can flow to the first liquid collector (20) of the molten salt heating device. The opening of the regulating pressure regulating valve (70) of the molten salt heating device is adjusted to regulate the liquid level of the molten salt in the first liquid collector (20), so that the molten salt in the first liquid collector (20) enters the first flow inlet of the heating structure (30) of the molten salt heating device or enters the first flow inlet and the second flow inlet of the heating structure (30), and heats the molten salt in the heating structure (30) through the first conductive element (40) and the second conductive element (50) of the molten salt heating device. When the molten salt heating device is in the second working state, the first storage tank (10) is disconnected from the first liquid collector (20), and the pressure regulating valve (70) is opened so that the molten salt in the first liquid collector (20) flows out through the heating structure (30).

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