Fused salt energy storage device and system

Abstract

The embodiment of the invention provides a fused salt energy storage device and system. The fused salt energy storage device comprises a fused salt backflow box, a plurality of fused salt storage boxes sequentially stacked on the upper surface of the fused salt backflow box in the height direction of the fused salt backflow box, and at least one heater arranged on the side surface of the fused salt backflow box in a penetrating mode in the width direction of the fused salt backflow box. Every two adjacent fused salt storage boxes are communicated with each other, and the fused salt storage boxes adjacent to the fused salt backflow box are further communicated with the fused salt backflow box. The fused salt backflow box is communicated with the fused salt storage box located at the top end through a fused salt pipeline group which is connected with a fused salt pump in series; wherein the heater is horizontally arranged, and the fused salt pipeline group is perpendicular to the heater. According to the fused salt energy storage device disclosed by the embodiment of the invention, the heater horizontally arranged in the fused salt backflow box facilitates later maintenance work, the heating efficiency can be improved, and peak regulation and frequency modulation can be performed more quickly and flexibly; the vertically arranged fused salt pipeline group can also reduce the length of the pipeline and avoid the blockage of the pipeline.

Description

Technical Field

[0001] The embodiments disclosed herein belong to the field of molten salt energy storage technology, specifically relating to a molten salt energy storage device and system. Background Technology

[0002] New energy power generation is characterized by randomness, intermittency, and high volatility. With the large-scale integration of new energy sources into the power grid, it poses a severe challenge to the safe operation of the grid. In recent years, many local power grids have introduced spot trading policies to encourage off-peak electricity consumption by widening the peak-valley price difference; some regions have even experienced negative electricity prices. Meanwhile, many enterprises have built their own new energy power sources, such as photovoltaic and wind power. Currently, utilizing the cheap off-peak electricity from the grid, as well as surplus electricity from self-built or unusable new energy sources, to provide stable and continuous industrial steam is a problem that needs to be solved. The coupling of thermal power generating units with molten salt thermal storage systems provides a solution for absorbing new energy sources, with electrically heated molten salt thermal storage technology being widely used.

[0003] The molten salt energy storage device in related technologies is arranged as a vertical external electric heater. Each storage unit has multiple molten salt modules, with a bottom tank for molten salt recirculation. Molten salt is pumped from the bottom tank into the vertically arranged electric heaters, heated, and then flows back to the top of the molten salt modules, thus achieving heat exchange through recirculation. However, the electric heaters suffer from dry burning, resulting in heat waste. Furthermore, the vertical arrangement makes maintenance extremely difficult when the heaters stop heating or are shut down for extended periods. Additionally, the vertical external electric heaters require long and numerous molten salt pipes for operation, which can easily lead to blockages. Summary of the Invention

[0004] The embodiments disclosed herein are intended to at least address one of the technical problems existing in the prior art, and to provide a molten salt energy storage device and system.

[0005] On one hand, embodiments of this disclosure provide a molten salt energy storage device, the molten salt energy storage device including a molten salt reflux tank, a plurality of molten salt tanks stacked sequentially on its upper surface along the height direction of the molten salt reflux tank, and at least one heater passing through its side surface along the width direction of the molten salt reflux tank.

[0006] The two adjacent molten salt tanks are interconnected, and the molten salt tank adjacent to the molten salt return tank is also connected to the molten salt return tank; and the molten salt return tank and the molten salt tank at the top are connected by a molten salt pipeline assembly with a molten salt pump connected in series; wherein,

[0007] The heater is horizontally positioned, and the molten salt pipe assembly is perpendicular to the heater.

[0008] Optionally, multiple heaters are provided, and the multiple heaters are arranged in an array along the length direction of the molten salt reflux tank.

[0009] Optionally, the heating end of the heater is located inside the molten salt reflux tank, and the power supply end of the heater is located outside the molten salt reflux tank to be connected to a power source.

[0010] Optionally, a connection hole is provided on one side of the molten salt reflux tank, and the heater is sealed to the connection hole by flange bolts.

[0011] Optionally, the molten salt pipeline assembly includes a main delivery pipeline, a first connecting pipeline, and a second connecting pipeline;

[0012] The inlet of the first connecting pipe is connected to the molten salt reflux tank, the outlet of the first connecting pipe is connected to the inlet of the main conveying pipe, the outlet of the main conveying pipe is connected to the inlet of the second connecting pipe, and the outlet of the second connecting pipe is connected to the molten salt storage tank located at the top; wherein,

[0013] The molten salt pump is connected in series on the main delivery pipeline, and the main delivery pipeline is perpendicular to the heater.

[0014] Optionally, the molten salt energy storage device further includes multiple overflow pipes;

[0015] Each overflow pipe is inserted through the bottom of the corresponding molten salt tank to connect two adjacent molten salt tanks, as well as to connect the molten salt tank adjacent to the molten salt return tank and the molten salt return tank.

[0016] The first end of the overflow pipe extends out of the bottom of the molten salt tank, and the second end of the overflow pipe is located inside the molten salt tank.

[0017] Optionally, the second end of the overflow pipe is lower than the upper edge of the molten salt tank by a predetermined distance.

[0018] Optionally, the second end of the overflow pipe is 5 cm below the upper edge of the molten salt tank.

[0019] Optionally, the molten salt storage tank is a square structure with an opening on the upper surface, and the heater is an electric heater.

[0020] On the other hand, embodiments of this disclosure provide a molten salt energy storage system, which includes a plurality of molten salt energy storage modules, each of which includes at least one of the molten salt energy storage devices described above.

[0021] The molten salt energy storage device and system of the present disclosure have a heater arranged horizontally in the molten salt reflux tank, which facilitates later maintenance and can improve heating efficiency, and enable faster and more flexible peak shaving and frequency regulation; the vertically arranged molten salt pipeline group can also reduce pipeline length and avoid pipeline blockage. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of an existing molten salt energy storage device;

[0023] Figure 2 This is a front view of a molten salt energy storage device according to an embodiment of the present disclosure;

[0024] Figure 3 This is a side view of a molten salt energy storage device according to another embodiment of the present disclosure. Detailed Implementation

[0025] To enable those skilled in the art to better understand the technical solutions of this disclosure, the disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] like Figure 1 As shown, the molten salt energy storage device in the related technology is arranged as a vertical external electric heater. Each storage unit has multiple molten salt modules, with a molten salt bottom tank for molten salt recirculation. Molten salt is pumped from the bottom tank into the vertically arranged electric heater, heated by the heater, and then flows back to the top of the molten salt modules, thus forming a recirculation to achieve heat exchange. The molten salt pump and the electric heater are connected by multiple molten salt pipes. Therefore, the vertically arranged electric heater suffers from dry burning, resulting in heat waste. Furthermore, its vertical arrangement makes maintenance extremely difficult when the heater stops heating or is shut down for extended periods. Additionally, the vertically arranged external electric heater requires a correspondingly long and numerous molten salt pipe to operate, which can easily lead to blockages in the molten salt pipes.

[0027] Based on this, the inventors designed a molten salt energy storage device 100 to solve the above problems. For example... Figure 2 and Figure 3 As shown, a molten salt energy storage device 100 includes a molten salt reflux tank 110, a plurality of molten salt storage tanks 120 stacked sequentially on the upper surface of the molten salt reflux tank 110 along its height direction, and at least one heater 130 passing through the side surface of the molten salt reflux tank 110 along its width direction.

[0028] The two adjacent molten salt storage tanks 120 are interconnected, and the molten salt storage tank 120 adjacent to the molten salt return tank 110 is also connected to the molten salt return tank 110. Furthermore, the molten salt return tank 110 and the top-positioned molten salt storage tank 120 are connected via a molten salt pipeline assembly 140 with a molten salt pump 141 connected in series. The heater 130 is horizontally positioned, and the molten salt pipeline assembly 140 is perpendicular to the heater 130.

[0029] Specifically, such as Figure 2 and Figure 3 As shown, a molten salt reflux tank 130 is located at the bottom, and multiple molten salt storage tanks 120 are stacked on top of the molten salt reflux tank 130. A molten salt pump 141 draws molten salt from the molten salt reflux tank 110 into the molten salt pipeline assembly 140 and transports it to the topmost molten salt storage tank 120. The drawn molten salt flows sequentially from the topmost molten salt storage tank 120 down to the lower molten salt storage tanks 120, eventually returning to the molten salt reflux tank 130. A heater 130 is horizontally positioned within the molten salt reflux tank 130 to heat the molten salt within. The molten salt pipeline assembly 140 is perpendicular to the heater 130.

[0030] The molten salt energy storage device of this disclosure, with its horizontally arranged heater, reduces workload and facilitates subsequent maintenance. Placing the heater within the molten salt reflux tank improves the heating efficiency of the molten salt, enabling faster heating and more flexible peak and frequency regulation. Furthermore, the vertical arrangement of the molten salt pipeline group shortens the required pipeline length and ensures smooth molten salt return to the molten salt reflux tank at room temperature or during maintenance, preventing pipeline blockage.

[0031] It should be noted that the specific number of molten salt storage tanks can be selected according to actual needs, and the embodiments disclosed herein do not impose specific limitations on this.

[0032] For example, such as Figure 1 and Figure 2 As shown, multiple heaters 130 are provided, and the multiple heaters 130 are arranged in an array along the length direction of the molten salt reflux tank 110. By providing multiple heaters 130, the molten salt can be heated better and faster, thereby improving efficiency.

[0033] For example, such as Figure 3 As shown, the heating end of the heater 130 is located inside the molten salt reflux tank 110, and the power supply end of the heater 130 is located outside the molten salt reflux tank 110 to be connected to a power source. The heating end of the heater 130 is located inside the molten salt reflux tank 110 to heat the molten salt, and the power supply end is located outside the molten salt reflux tank 110 to be connected to a power source to power the heater 130 and drive its operation.

[0034] Furthermore, a connection hole (not shown in the figure) is opened on one side of the molten salt reflux box 110, and the heater 130 is sealed to the connection hole by flange bolts.

[0035] Specifically, a connection hole is provided on the side of the molten salt reflux box 110. After the heater is inserted, flange bolts are used to make the heater 130 and the connection hole achieve a sealed connection, which facilitates installation and subsequent inspection and maintenance.

[0036] For example, such as Figure 2 and Figure 3 As shown, the molten salt pipeline assembly 140 includes a main delivery pipeline 142, a first connecting pipeline 143, and a second connecting pipeline 144. The inlet of the first connecting pipeline 143 is connected to the molten salt return tank 110, the outlet of the first connecting pipeline 143 is connected to the inlet of the main delivery pipeline 142, the outlet of the main delivery pipeline 142 is connected to the inlet of the second connecting pipeline 144, and the outlet of the second connecting pipeline 144 is connected to the molten salt storage tank 120 located at the top. The molten salt pump 141 is connected in series on the main delivery pipeline 142, and the main delivery pipeline 142 is perpendicular to the heater 130.

[0037] Specifically, such as Figure 2 and Figure 3 As shown, under the action of the molten salt pump 141, the molten salt in the molten salt return tank 110 enters the main delivery pipeline 142 through the first connecting pipeline 143, and then enters the second connecting pipeline 144 from the main delivery pipeline 142, finally flowing into the topmost molten salt storage tank 120. The molten salt return tank 110 and the topmost molten salt storage tank 120 are directly connected by a vertical pipeline (main delivery pipeline 142), ensuring that the entire device has only one vertically arranged molten salt pipeline. This prevents the molten salt from clogging the pipeline and avoids the need for unnecessary pipelines, reducing costs.

[0038] It is not difficult to understand that molten salt commonly used is ternary salt (potassium nitrate, sodium nitrate, and sodium nitrite), with a freezing point of 90°C. The temperature required to reach the flow condition is 140°C. At room temperature or during maintenance, the vertically arranged main conveying pipeline can ensure that the molten salt can flow smoothly back to the molten salt return box.

[0039] The molten salt energy storage device of the present disclosure can avoid molten salt clogging of the pipes by setting up the molten salt pipe group, and can also avoid setting up unnecessary pipes, thereby reducing cost expenditure.

[0040] For example, such as Figure 2 and Figure 3As shown, the molten salt energy storage device 100 also includes multiple overflow pipes (not shown in the figure). Each overflow pipe is inserted through the bottom of the corresponding molten salt storage tank 120, for connecting two adjacent molten salt storage tanks 120, and connecting the molten salt storage tank 120 adjacent to the molten salt return tank 110. The first end of the overflow pipe extends out of the bottom of the molten salt storage tank 120, and the second end of the overflow pipe is located inside the molten salt storage tank 120.

[0041] Specifically, such as Figure 2 and Figure 3 As shown, for the molten salt in each molten salt storage tank 120 to flow smoothly downwards, it needs to rely on its corresponding overflow pipe. When the height of the molten salt in the upper molten salt storage tank 120 exceeds the height of the overflow pipe, the portion of molten salt exceeding the overflow pipe height flows into the next molten salt storage tank 120 through the overflow pipe, and so on, eventually flowing into the molten salt return tank 110. Together with the molten salt pipeline assembly 140, it constitutes the entire molten salt circulation process.

[0042] The molten salt energy storage device of the present disclosure, through the provided overflow pipe, can better realize the top-to-bottom flow of molten salt in the molten salt storage tank, which is convenient and simple.

[0043] Furthermore, the second end of the overflow pipe is positioned below the upper edge of the molten salt storage tank 120 by a predetermined distance. Setting the height of the second end of the overflow pipe below the upper edge of the molten salt storage tank 120 allows for better overflow of molten salt through the overflow pipe; for example, the second end of the overflow pipe is positioned 5cm below the upper edge of the molten salt storage tank 120.

[0044] For example, such as Figure 2 and Figure 3 As shown, the molten salt storage tank 120 is a square structure with an opening on the upper surface, and the heater 130 is an electric heater.

[0045] On the other hand, embodiments of this disclosure provide a molten salt energy storage system, which includes multiple molten salt energy storage modules, each of which includes at least one molten salt energy storage device as described above. The specific structure of the molten salt energy storage device can be found in the preceding descriptions and will not be elaborated upon here.

[0046] The molten salt energy storage system of this disclosure, with its horizontally arranged heaters, reduces workload and facilitates subsequent maintenance. Placing the heaters within the molten salt reflux tank improves the heating efficiency of the molten salt, enabling faster heating and more flexible peak and frequency regulation. Furthermore, the vertical arrangement of the molten salt piping group shortens the required piping length and ensures smooth molten salt return to the molten salt reflux tank at room temperature or during maintenance, preventing pipe blockage.

[0047] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. A molten salt energy storage device, characterized in that, The molten salt energy storage device includes a molten salt reflux tank, a plurality of molten salt storage tanks stacked sequentially on its upper surface along the height direction of the molten salt reflux tank, and at least one heater passing through its side surface along the width direction of the molten salt reflux tank. The two adjacent molten salt tanks are interconnected, and the molten salt tank adjacent to the molten salt return tank is also connected to the molten salt return tank; and the molten salt return tank and the molten salt tank at the top are connected by a molten salt pipeline assembly with a molten salt pump connected in series; wherein, The heater is horizontally positioned, and the molten salt pipe assembly is perpendicular to the heater.

2. The molten salt energy storage device according to claim 1, characterized in that, The heater is provided in multiple ways, and the multiple heaters are arranged in an array along the length direction of the molten salt reflux tank.

3. The molten salt energy storage device according to claim 1, characterized in that, The heating end of the heater is located inside the molten salt reflux tank, and the power supply end of the heater is located outside the molten salt reflux tank to be connected to a power source.

4. The molten salt energy storage device according to claim 1, characterized in that, The molten salt reflux tank has a connection hole on one side, and the heater is sealed to the connection hole by flange bolts.

5. The molten salt energy storage device according to any one of claims 1 to 4, characterized in that, The molten salt pipeline assembly includes a main delivery pipeline, a first connecting pipeline, and a second connecting pipeline; The inlet of the first connecting pipe is connected to the molten salt reflux tank, the outlet of the first connecting pipe is connected to the inlet of the main conveying pipe, the outlet of the main conveying pipe is connected to the inlet of the second connecting pipe, and the outlet of the second connecting pipe is connected to the molten salt storage tank located at the top; wherein, The molten salt pump is connected in series on the main delivery pipeline, and the main delivery pipeline is perpendicular to the heater.

6. The molten salt energy storage device according to any one of claims 1 to 4, characterized in that, The molten salt energy storage device also includes multiple overflow pipes; Each overflow pipe is inserted through the bottom of the corresponding molten salt tank to connect two adjacent molten salt tanks, as well as to connect the molten salt tank adjacent to the molten salt return tank and the molten salt return tank. The first end of the overflow pipe extends out of the bottom of the molten salt tank, and the second end of the overflow pipe is located inside the molten salt tank.

7. The molten salt energy storage device according to claim 6, characterized in that, The second end of the overflow pipe is lower than the upper edge of the molten salt tank by a predetermined distance.

8. The molten salt energy storage device according to claim 7, characterized in that, The second end of the overflow pipe is 5 cm below the upper edge of the molten salt tank.

9. The molten salt energy storage device according to any one of claims 1 to 4, characterized in that, The molten salt storage tank is a square structure with an opening on the upper surface, and the heater is an electric heater.

10. A molten salt energy storage system, characterized in that, The molten salt energy storage system includes multiple molten salt energy storage modules, and each molten salt energy storage module includes at least one molten salt energy storage device as described in any one of claims 1 to 9.

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