Electric heating fused salt steam supply system capable of switching heat storage and release and switching method

Abstract

The embodiment of the invention provides an electric heating fused salt steam supply system capable of switching heat storage and release and a switching method. The system comprises a high-temperature fused salt storage tank; the input end of the high-temperature molten salt pump is communicated with the outlet of the high-temperature molten salt storage tank; an inlet of the heat exchanger is communicated with the output end of the high-temperature molten salt pump; an inlet of the low-temperature fused salt storage tank is communicated with an outlet of the heat exchanger; the input end of the low-temperature fused salt pump is communicated with the outlet of the low-temperature fused salt storage tank; an inlet of the heater is communicated with the output end of the low-temperature molten salt pump, and an outlet of the heater is communicated with an inlet of the high-temperature molten salt storage tank; the first valve is connected between the outlet of the heat exchanger and the inlet of the heater; the input end of the fused salt circulating pump is communicated with the outlet of the heater, and the output end of the fused salt circulating pump is communicated with the inlet of the heat exchanger.

Description

Technical Field

[0001] The embodiments of the present disclosure belong to the technical field of molten salt heat storage, and specifically relate to an electric molten salt steam supply system with switchable heat storage and release, and a switching method. Background Art

[0002] At present, my country's renewable energy sources such as wind energy and solar energy are developing rapidly year by year. In addition, the electricity consumption of the whole society is increasing year by year, and the peak-to-valley difference in electricity consumption of the power grid is increasing.

[0003] Molten salt energy storage technology has been widely used due to its low average cost, long service life, and clean, pollution-free design. However, traditional molten salt heat storage systems still have some drawbacks in practical applications. For example, when the system is started and stopped, the molten salt is easily oxidized when it comes into contact with air. When the system is operated at low flow rates and long pipeline distances, the presence of gas in the pipeline can cause pipeline surge. In severe cases, this can cause cracks in pipeline and equipment welds, resulting in molten salt leakage. At the same time, the molten salt needs to be repeatedly transferred in and out of the storage tank, which increases heat loss. The simultaneous operation of multiple molten salt pumps requires overcoming the height difference between the storage tanks and the system equipment, resulting in increased operating costs. Furthermore, in practical applications, traditional molten salt heat storage systems also suffer from pipeline vibration, large investment in molten salt materials, and complex dual-tank control operations.

[0004] Therefore, there is a strong market demand for a smoothly switchable heat storage and release system that can realize electric molten salt steam supply. Summary of the Invention

[0005] The embodiments of the present disclosure aim to solve at least one of the technical problems existing in the prior art and provide an electric molten salt steam supply system with switchable heat storage and release and a switching method.

[0006] A first aspect of an embodiment of the present disclosure provides an electric molten salt steam supply system with switchable heat storage and release, comprising: a high-temperature molten salt storage tank;

[0007] A high-temperature molten salt pump, the input end of which is connected to the outlet of the high-temperature molten salt storage tank;

[0008] The inlet of the heat exchanger is connected to the output end of the high-temperature molten salt pump;

[0009] The inlet of the low-temperature molten salt storage tank is connected to the outlet of the heat exchanger;

[0010] A low-temperature molten salt pump, the input end of which is connected to the outlet of the low-temperature molten salt storage tank;

[0011] The inlet of the heater is connected to the output end of the low-temperature molten salt pump, and the outlet of the heater is connected to the inlet of the high-temperature molten salt storage tank;

[0012] a first valve connected between the outlet of the heat exchanger and the inlet of the heater;

[0013] The input end of the molten salt circulation pump is communicated with the outlet of the heater, and the output end of the molten salt circulation pump is communicated with the inlet of the heat exchanger.

[0014] Furthermore, it also includes: a second valve, which is arranged in the pipe section between the output end of the molten salt circulation pump and the inlet of the heat exchanger.

[0015] Furthermore, it also includes: a third valve, which is arranged in the pipe section between the output end of the high-temperature molten salt pump and the inlet of the heat exchanger.

[0016] Furthermore, it also includes: a fourth valve, which is arranged in the pipe section between the outlet of the heat exchanger and the inlet of the low-temperature molten salt storage tank.

[0017] Furthermore, it also includes: a fifth valve, which is arranged in the pipe section between the outlet of the low-temperature molten salt storage tank and the inlet of the heater.

[0018] Furthermore, it also includes: a sixth valve, which is arranged in the pipe section between the outlet of the heater and the inlet of the high-temperature molten salt storage tank.

[0019] Optionally, the heater includes an electric heater.

[0020] Optionally, the pump body of the high-temperature molten salt pump is configured to extend into the interior of the high-temperature molten salt storage tank.

[0021] Optionally, the pump body of the low-temperature molten salt pump is configured to extend into the interior of the low-temperature molten salt storage tank.

[0022] A first aspect of the embodiments of the present disclosure provides a method for switching heat storage and release of electric molten salt steam supply, comprising:

[0023] Control the third valve and the fourth valve to open, and close the first valve, the second valve, the fifth valve and the sixth valve, and control the high-temperature molten salt pump to start, pump the high-temperature molten salt in the high-temperature molten salt storage tank into the heat exchanger to release heat and then return it to the low-temperature molten salt storage tank;

[0024] Control the fifth valve and the sixth valve to open, and close the third valve and the fourth valve, control the low-temperature molten salt pump to start, pump the low-temperature molten salt in the low-temperature molten salt storage tank into the heater to absorb heat and then return it to the high-temperature molten salt storage tank;

[0025] The first valve and the second valve are controlled to open, and the fifth valve and the sixth valve are closed. The high-temperature molten salt pump and the low-temperature molten salt pump are controlled to close and the molten salt circulation pump is started to drive the molten salt to form a closed circulation between the heater and the heat exchanger.

[0026] The beneficial effects of the embodiments of the present disclosure include:

[0027] The system operates in two modes: heat storage and direct supply. In the heat storage mode, molten salt circulates conventionally through the storage tanks. In the direct supply mode, molten salt flows directly through a bypass pipe in a closed loop from electric heater 6 to heat exchanger 3 to electric heater 6. This solves the piping vibration problem of traditional molten salt heat storage systems. The closed cycle achieves isochronous heat storage and release, with a 1:1 heat storage and release ratio. This allows for a smaller amount of molten salt to meet heat exchange requirements. Furthermore, the closed cycle system requires minimal equipment, simplifies operation and control, and eliminates the issue of liquid level imbalance in high and low temperature molten salt storage tanks. This improves system heat exchange efficiency, reduces operating costs, and meets user needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a structural schematic diagram of a switchable heat storage and release electric molten salt steam supply system according to an embodiment of the present disclosure;

[0029] Figure 2 This is a flow chart of a heat storage and release switching method for electric molten salt steam supply according to another embodiment of the present disclosure.

[0030] In the figure, 1. high-temperature molten salt storage tank; 2. high-temperature molten salt pump; 3. heat exchanger; 4. low-temperature molten salt storage tank; 5. low-temperature molten salt pump; 6. heater; 7. first valve; 8. molten salt circulation pump; 9. second valve; 10. third valve; 11. fourth valve; 12. fifth valve; 13. sixth valve. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the technical solutions of the present disclosure, the present disclosure is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0032] The following is a further detailed description of the embodiments of the present application in conjunction with the accompanying drawings and examples. The detailed descriptions and drawings of the following examples are used to illustrate the principles of the present application, but are not used to limit the scope of the present application, that is, the present application is not limited to the described embodiments. In the description of the present application, it should be noted that, unless otherwise specified, the meaning of "multiple" is more than two; the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "inside", "outside", etc. is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not perpendicular in the strict sense, but is within the allowable error range. "Parallel" is not parallel in the strict sense, but is within the allowable error range.

[0033] It should also be noted that, in the description of this application, unless otherwise specified or limited, the terms "installed," "connected," and "connected" should be understood broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0034] like Figure 1 As shown, an electric molten salt steam supply system with switchable heat storage and release includes: a high-temperature molten salt storage tank 1, a high-temperature molten salt pump 2, a heat exchanger 3, a low-temperature molten salt storage tank 4, a low-temperature molten salt pump 5, a heater 6, a first valve 7, and a molten salt circulation pump 8. The input end of the high-temperature molten salt pump 2 is connected to the outlet of the high-temperature molten salt storage tank 1, the inlet of the heat exchanger 3 is connected to the output end of the high-temperature molten salt pump 2, the inlet of the low-temperature molten salt storage tank 4 is connected to the outlet of the heat exchanger 3, and the input end of the low-temperature molten salt pump 5 is connected to the outlet of the low-temperature molten salt storage tank 4.

[0035] The inlet of the heater 6 is connected to the output end of the low-temperature molten salt pump 5, the outlet of the heater 6 is connected to the inlet of the high-temperature molten salt storage tank 1, the first valve 7 is connected between the outlet of the heat exchanger 3 and the inlet of the heater 6, the input end of the molten salt circulation pump 8 is connected to the outlet of the heater 6, and the output end of the molten salt circulation pump 8 is connected to the inlet of the heat exchanger 3.

[0036] In some embodiments, the steam supply system further includes a second valve 9 , which is disposed in a pipe section between the output end of the molten salt circulation pump 8 and the inlet of the heat exchanger 3 .

[0037] In some embodiments, the steam supply system further includes a third valve 10, which is disposed in a pipe section between the output end of the high-temperature molten salt pump 2 and the inlet of the heat exchanger 3. Specifically, the output end of the second valve 9 is located downstream of the output end of the third valve 10.

[0038] In some embodiments, the steam supply system further includes a fourth valve 11 , which is disposed in a pipe section between the outlet of the heat exchanger 3 and the inlet of the low-temperature molten salt storage tank 4 .

[0039] In some embodiments, the steam supply system further includes a fifth valve 12, which is disposed in a pipe section between the outlet of the low-temperature molten salt storage tank 4 and the inlet of the heater 6. Specifically, the input end of the first valve 7 is located upstream of the input end of the fourth valve 11, and the output end of the first valve 7 is located downstream of the output end of the fifth valve 12.

[0040] In some embodiments, the steam supply system further includes a sixth valve 13, which is disposed in a pipe section between the outlet of the heater 6 and the inlet of the high-temperature molten salt storage tank 1. Specifically, the input end of the molten salt circulation pump 8 is located upstream of the input end of the sixth valve 13.

[0041] In some embodiments, the heater 6 includes an electric heater.

[0042] In some embodiments, the pump body of the high-temperature molten salt pump 2 is configured to extend into the interior of the high-temperature molten salt storage tank 1 .

[0043] In some embodiments, the pump body of the low-temperature molten salt pump 5 is configured to extend into the interior of the low-temperature molten salt storage tank 4 .

[0044] Specifically, the present invention adopts the following technical solutions, including:

[0045] The high-temperature molten salt storage tank 1 is connected to the high-temperature molten salt pump 2, the pump body of the high-temperature molten salt pump 2 extends into the interior of the high-temperature molten salt storage tank 1, the outlet of the high-temperature molten salt pump 2 is connected to the inlet of the heat exchanger 3 through the third valve 10, and the outlet of the heat exchanger 3 is connected to the low-temperature molten salt storage tank 4 through the fourth valve 11.

[0046] The low-temperature molten salt storage tank 4 is connected to the low-temperature molten salt pump 5, the pump body of the low-temperature molten salt pump 5 extends into the interior of the low-temperature molten salt storage tank 4, the outlet of the low-temperature molten salt pump 5 is connected to the inlet of the electric heater 6 through the fifth valve 12, and the outlet of the electric heater 6 is connected to the high-temperature molten salt storage tank 1 through the sixth valve 13.

[0047] The inlet of the molten salt circulation pump 8 is connected to the pipe section between the electric heater 6 and the sixth valve 13, the outlet of the molten salt circulation pump 8 is connected to the pipe section between the third valve 10 and the inlet of the heat exchanger 3, and the pipe between the outlet of the heat exchanger 3 and the fourth valve 11 leads to a bypass pipe provided with a first valve 7, and the bypass pipe is connected to the pipe section between the fifth valve 12 and the electric heater 6.

[0048] The high-temperature molten salt pump 2 extracts the high-temperature molten salt in the high-temperature molten salt storage tank 1 during the system heat release link, and pumps it to the heat exchanger 3 through the third valve 10 for heat release. The low-temperature molten salt after heat release returns to the low-temperature molten salt storage tank 4 through the fourth valve 11.

[0049] The low-temperature molten salt pump 5 extracts the low-temperature molten salt in the low-temperature molten salt storage tank 4 in the system heat storage link, and pumps it to the electric heater 6 through the fifth valve 12 for heat absorption. The high-temperature molten salt after heat absorption returns to the high-temperature molten salt storage tank 1 through the sixth valve 13.

[0050] During the closed circulation process of the system, the molten salt circulation pump 8 pumps the high-temperature molten salt from the outlet of the electric heater 6 to the inlet of the heat exchanger 3 through the second valve 9. After the high-temperature molten salt releases heat, it returns to the inlet of the electric heater 6 through the first valve 7, completing the closed circulation. At this time, the high-temperature molten salt storage tank 1, the high-temperature molten salt pump 2, the low-temperature molten salt storage tank 4, and the low-temperature molten salt pump 5 are all bypassed.

[0051] Compared with the prior art, the present invention has the following advantages:

[0052] This invention proposes an electric molten salt steam supply system with switchable heat storage and release, enabling both heat storage and direct supply modes. In the heat storage mode, the molten salt circulates conventionally through a storage tank. In the direct supply mode, the molten salt flows directly through a bypass pipe in a closed loop ("electric heater 6 -> heat exchanger 3 -> electric heater 6"). This solves the pipeline vibration problem of traditional molten salt heat storage systems. The closed cycle achieves isochronous heat storage and release, with a 1:1 heat storage and release ratio, requiring less molten salt to meet heat exchange requirements. Furthermore, the closed cycle system requires minimal equipment, simplifies operation and control, and eliminates the problem of liquid level imbalance in the high and low temperature molten salt storage tanks 4. This improves system heat exchange efficiency, reduces operating costs, and meets user needs.

[0053] refer to Figure 2 According to a first aspect of the embodiments of the present disclosure, a method for switching between heat storage and heat release in an electric molten salt steam supply is provided, comprising:

[0054] S101, control the third valve 10 and the fourth valve 11 to open, and close the first valve 7, the second valve 9, the fifth valve 12 and the sixth valve 13, and control the high-temperature molten salt pump 2 to start, pump the high-temperature molten salt in the high-temperature molten salt storage tank 1 into the heat exchanger 3 to release heat and then return it to the low-temperature molten salt storage tank 4.

[0055] S102, control the fifth valve 12 and the sixth valve 13 to open, and close the third valve 10 and the fourth valve 11, control the low-temperature molten salt pump 5 to start, and pump the low-temperature molten salt in the low-temperature molten salt storage tank 4 into the heater 6 to absorb heat and then flow back to the high-temperature molten salt storage tank 1.

[0056] S103, control the first valve 7 and the second valve 9 to open, and close the fifth valve 12 and the sixth valve 13, and control the high-temperature molten salt pump 2 and the low-temperature molten salt pump 5 to close and start the molten salt circulation pump 8 to drive the molten salt to form a closed circulation between the heater 6 and the heat exchanger 3.

[0057] Specifically, the stable switchable heat storage and release system and operation method of the electric molten salt steam supply are operated according to the following method:

[0058] 1. Conventional heat release link: open the third valve 10 and the fourth valve 11, close the first valve 7, the second valve 9, the fifth valve 12 and the sixth valve 13, start the high-temperature molten salt pump 2, extract the high-temperature molten salt in the high-temperature molten salt storage tank 1, and pump it to the heat exchanger 3 through the third valve 10 for heat release. The low-temperature molten salt after heat release returns to the low-temperature molten salt storage tank 4 through the fourth valve 11.

[0059] 2. Conventional heat storage link: open the fifth valve 12 and the sixth valve 13, close the third valve 10, the fourth valve 11, the first valve 7 and the second valve 9, start the low-temperature molten salt pump 5, extract the low-temperature molten salt in the low-temperature molten salt storage tank 4, and pump it to the electric heater 6 through the fifth valve 12 for heat absorption. After heat absorption, the high-temperature molten salt returns to the high-temperature molten salt storage tank 1 through the sixth valve 13.

[0060] 3. During the conventional simultaneous operation of heat storage and release, the above steps 1 and 2 are performed simultaneously, and the liquid level balance of the high-temperature molten salt storage tank 1 and the low-temperature molten salt storage tank 4 is controlled to avoid the corresponding system being shut down due to the emptying of the molten salt in a single storage tank.

[0061] 4. Direct Supply Mode: Molten salt flows directly through a bypass pipeline in a closed cycle from electric heater 6 to heat exchanger 3 to electric heater 6, achieving isochronous heat storage and release, with a 1:1 ratio. In this mode, open the first valve 7 and second valve 9, close the third valve 10, fourth valve 11, fifth valve 12, and sixth valve 13, shut down the high-temperature molten salt pump 2 and the low-temperature molten salt pump 5, and start the molten salt circulation pump 8. During this closed cycle, the molten salt circulation pump 8 pumps the high-temperature molten salt from the outlet of electric heater 6 through the second valve 9 to the inlet of heat exchanger 3. After releasing heat, the high-temperature molten salt returns to the inlet of electric heater 6 through the first valve 7, completing the closed cycle. At this point, the high-temperature molten salt storage tank 1, high-temperature molten salt pump 2, low-temperature molten salt storage tank 4, and low-temperature molten salt pump 5 are all bypassed.

[0062] This invention proposes a smoothly switchable heat storage and discharge system and operating method for electric molten salt steam supply, enabling both heat storage and direct supply operating modes. In the heat storage mode, molten salt circulates conventionally through a storage tank; in the direct supply mode, molten salt flows directly through a bypass pipe in a closed cycle (electric heater 6 → heat exchanger 3 → electric heater 6). This solves the pipeline vibration problem of traditional molten salt heat storage systems. The closed cycle achieves isochronous heat storage and discharge, with a 1:1 heat storage and release ratio, requiring less molten salt to meet heat exchange requirements. Furthermore, the closed cycle system requires minimal equipment, simplifies operation and control, and eliminates the problem of liquid level imbalance in the high and low temperature molten salt storage tanks 4. This improves system heat exchange efficiency and reduces operating costs to meet user needs.

[0063] It is understood that the above embodiments are merely exemplary embodiments for illustrating the principles of the present disclosure, and the present disclosure is not limited thereto. Those skilled in the art may make various modifications and improvements without departing from the spirit and substance of the present disclosure, and such modifications and improvements are also considered to be within the scope of protection of the present disclosure.

Claims

1. An electric molten salt steam supply system with switchable heat storage and release, characterized in that: include: High-temperature molten salt storage tanks; A high-temperature molten salt pump, the input end of which is connected to the outlet of the high-temperature molten salt storage tank; The inlet of the heat exchanger is connected to the output end of the high-temperature molten salt pump; The inlet of the low-temperature molten salt storage tank is connected to the outlet of the heat exchanger; A low-temperature molten salt pump, the input end of which is connected to the outlet of the low-temperature molten salt storage tank; The inlet of the heater is connected to the output end of the low-temperature molten salt pump, and the outlet of the heater is connected to the inlet of the high-temperature molten salt storage tank; a first valve connected between the outlet of the heat exchanger and the inlet of the heater; The input end of the molten salt circulation pump is communicated with the outlet of the heater, and the output end of the molten salt circulation pump is communicated with the inlet of the heat exchanger.

2. The steam supply system according to claim 1, characterized in that: Also includes: A second valve is provided in a pipe section between the output end of the molten salt circulation pump and the inlet of the heat exchanger.

3. The steam supply system according to claim 1, characterized in that: Also includes: A third valve is provided in the pipe section between the output end of the high-temperature molten salt pump and the inlet of the heat exchanger.

4. The steam supply system according to claim 1, characterized in that: Also includes: A fourth valve is provided in a pipe section between the outlet of the heat exchanger and the inlet of the low-temperature molten salt storage tank.

5. The steam supply system according to claim 1, characterized in that: Also includes: A fifth valve is provided in a pipe section between the outlet of the low-temperature molten salt storage tank and the inlet of the heater.

6. The steam supply system according to claim 1, characterized in that: Also includes: A sixth valve is provided in a pipe section between the outlet of the heater and the inlet of the high-temperature molten salt storage tank.

7. The steam supply system according to claim 1, characterized in that: The heater includes an electric heater.

8. The steam supply system according to claim 1, characterized in that: The pump body of the high-temperature molten salt pump is configured to extend into the interior of the high-temperature molten salt storage tank.

9. The steam supply system according to claim 1, characterized in that: The pump body of the low-temperature molten salt pump is arranged to extend into the interior of the low-temperature molten salt storage tank.

10. A heat storage and release switching method for electric molten salt steam supply, characterized in that: include: Control the third valve and the fourth valve to open, and close the first valve, the second valve, the fifth valve and the sixth valve, and control the high-temperature molten salt pump to start, pump the high-temperature molten salt in the high-temperature molten salt storage tank into the heat exchanger to release heat and then return it to the low-temperature molten salt storage tank; Control the fifth valve and the sixth valve to open, and close the third valve and the fourth valve, control the low-temperature molten salt pump to start, pump the low-temperature molten salt in the low-temperature molten salt storage tank into the heater to absorb heat and then return it to the high-temperature molten salt storage tank; The first valve and the second valve are controlled to open, and the fifth valve and the sixth valve are closed. The high-temperature molten salt pump and the low-temperature molten salt pump are controlled to close and the molten salt circulation pump is started to drive the molten salt to form a closed circulation between the heater and the heat exchanger.

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