Molten Salt Energy Storage System

Abstract

This invention relates to the field of molten salt energy storage technology and discloses a molten salt energy storage system. The molten salt energy storage system includes: a molten salt tank with an inner cavity and an outlet and inlet communicating with the inner cavity; the inner cavity is capable of storing nitrogen and high-temperature molten salt for energy storage; a nitrogen circulation pipeline connected between the outlet and inlet for exporting nitrogen from the molten salt tank through the outlet and importing it through the inlet; and a flow-dispersing device located in the inner cavity and communicating with the inlet, the flow-dispersing device including a jet nozzle, through which nitrogen introduced from the inlet is exported to agitate the molten salt. This invention places the flow-dispersing device in the inner cavity of the molten salt tank. The nitrogen exported through the jet nozzle of the flow-dispersing device forms an upward flow of bubbles, agitating the molten salt in the tank. This enhances the fluidity of the molten salt within the tank, improves the heat exchange effect between the molten salt and the heating and releasing units within the tank, increases the heat transfer efficiency of the molten salt, and improves the heat exchange effect between the energy release stage and the water in the water pipeline. It also improves the uniformity of nitrogen sealing.

Description

Technical Field

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

[0002] Molten salt energy storage systems typically consist of a molten salt tank, a transport unit, a heating unit, a heat release unit, and a nitrogen sealing unit. By storing electrical or thermal energy in molten salt during off-peak or peak periods, the energy is released during peak or off-peak periods to generate high-temperature steam for power generation or heating. Currently, the molten salt in molten salt energy storage systems remains stationary in the tank, resulting in poor heat transfer between the molten salt and the heating and heat release units, thus affecting the heat transfer efficiency of the molten salt. Summary of the Invention

[0003] In view of this, the present invention provides a molten salt energy storage system to solve the problem that the molten salt in the current molten salt energy storage system is in a static state in the molten salt tank, resulting in poor heat transfer between the molten salt and the heating and heat release units.

[0004] This invention provides a molten salt energy storage system, comprising:

[0005] A molten salt tank has an inner cavity and an outlet and an inlet communicating with the inner cavity, the inner cavity being capable of storing nitrogen and high-temperature molten salt for energy storage;

[0006] A nitrogen circulation pipeline, connected between the outlet and the inlet, is used to export nitrogen gas from the molten salt tank through the outlet and import it through the inlet to nitrogen seal the molten salt.

[0007] A flow disturbance device is disposed in the inner cavity and communicates with the inlet. The flow disturbance device includes a jet section, through which nitrogen gas introduced by the inlet is discharged to disturb the molten salt.

[0008] A water passage is provided for guiding water. The water passage is at least partially heat-exchangeably installed in the molten salt tank, so that the low-temperature water in the water passage exchanges heat with the high-temperature molten salt in the molten salt tank, thereby converting the water into high-temperature steam for energy release.

[0009] Beneficial effects: This invention provides a molten salt energy storage system. A turbulence device is installed in the inner cavity of the molten salt tank. Nitrogen gas is discharged through the jet section of the turbulence device to form an upward flow of bubbles, thereby disturbing the molten salt in the molten salt tank. This enhances the fluidity of the molten salt in the tank, improves the heat exchange effect between the molten salt and the heating and heat release units in the tank, increases the heat transfer efficiency of the molten salt, and improves the heat exchange effect between the energy release stage and the water in the water pipeline. It also improves the uniformity of nitrogen sealing.

[0010] In one alternative embodiment, the jet section is configured as a nozzle through which nitrogen introduced by the inlet is radially directed to the molten salt.

[0011] Beneficial effects: The jet section is constructed as a nozzle so that the nitrogen introduced from the inlet can be radially guided to the molten salt, increasing the range of nitrogen's guiding effect on the molten salt, thereby enhancing the range of nitrogen's disturbance to the molten salt in the molten salt tank.

[0012] In one optional embodiment, the turbulence device further includes a flow guide pipe, which is connected to the nitrogen circulation pipeline at the inlet, and the jet section is disposed on the flow guide pipe.

[0013] Beneficial effect: The jet section is installed in the cavity by using a drainage pipe located in the inner cavity and connected to the inlet of the molten salt tank, so that the jet section is located in the inner space of the cavity, thereby allowing the nitrogen gas discharged by the jet section to fully disturb the molten salt.

[0014] In one alternative embodiment, the drainage pipe is disposed near the bottom of the molten salt tank;

[0015] And / or, the drain pipe is arranged in a coiled shape so that the projection of the drain pipe in the direction of the bottom of the molten salt tank covers the bottom of the molten salt tank, and a plurality of the jets are evenly spaced on the drain pipe.

[0016] Beneficial effects: Due to gravity, molten salt mostly resides at the bottom of the molten salt vessel. Positioning the drainage pipe close to the bottom of the vessel allows the jet nozzles to be positioned close to the bottom as well, thereby improving the effectiveness of the nitrogen gas from the jet nozzles in disturbing the molten salt. The drainage pipes are coiled, ensuring their distribution covers the entire cross-section of the molten salt vessel. This, combined with multiple jet nozzles evenly spaced on the drainage pipes, further enhances the effectiveness of the nitrogen gas from the jet nozzles in disturbing the molten salt.

[0017] In one optional embodiment, the molten salt energy storage system further includes:

[0018] A temperature control component is disposed between the water passage pipeline and the nitrogen circulation pipeline. The temperature control component is used to exchange heat between the high-temperature nitrogen gas in the nitrogen circulation pipeline and the low-temperature water in the water passage pipeline to preheat the water in the water passage pipeline.

[0019] Beneficial effects: Installing a temperature control component between the water supply pipeline and the nitrogen circulation pipeline allows for the preheating of the softened water in the water supply pipeline through heat exchange between high-temperature nitrogen and low-temperature softened water. This avoids thermal stress problems caused by excessive temperature differences during energy release in the molten salt energy storage system, enhancing equipment safety. Furthermore, it fully utilizes the relatively high temperature heat in the nitrogen circulation, improving the nitrogen's heat recovery efficiency.

[0020] In one optional implementation, the temperature control component includes:

[0021] The first heat exchanger is heat-exchangeably disposed between the water pipeline and the nitrogen circulation pipeline to preheat the water in the water pipeline.

[0022] Beneficial effects: The softened water in the water pipeline is preheated by using a heat exchanger that is heat-exchangeably installed between the water pipeline and the nitrogen circulation pipeline. The structure is simple and the heat exchange is highly efficient.

[0023] In one optional embodiment, the temperature control component further includes:

[0024] A compressor is located in the nitrogen circulation pipeline and downstream of the first heat exchanger, used to compress the low-temperature nitrogen gas after heat exchange into high-temperature nitrogen gas.

[0025] The second heat exchanger is located downstream of the compressor and is heat-exchangeably disposed between the water pipeline and the nitrogen circulation pipeline to preheat the water in the water pipeline.

[0026] Beneficial effects: By using a second heat exchanger that can be heat-exchanged between the water supply pipeline and the nitrogen circulation pipeline, in conjunction with the compressor, the softened water in the water supply pipeline can be preheated twice. This allows the softened water in the water supply pipeline to be preheated multiple times, enabling staged recovery and utilization of heat, reducing heat waste, and improving the overall thermal efficiency of the molten salt energy storage system.

[0027] In one optional embodiment, the nitrogen circulation pipeline includes an outlet pipeline located upstream of the temperature control component and an inlet pipeline located downstream of the temperature control component.

[0028] The molten salt energy storage system also includes:

[0029] The third heat exchanger is heat-exchangeably disposed between the outlet pipe and the inlet pipe, and is used to exchange heat between the high-temperature nitrogen in the outlet pipe and the low-temperature nitrogen in the inlet pipe, so as to raise the temperature of the nitrogen flowing back to the molten salt tank from the inlet pipe.

[0030] Beneficial effects: After the nitrogen gas in the nitrogen circulation pipeline exchanges heat with the softened water through the temperature control component, the nitrogen temperature in the upstream outlet pipeline of the nitrogen circulation pipeline is higher than the nitrogen temperature in the downstream inlet pipeline. Therefore, a third heat exchanger is installed between the outlet pipeline and the inlet pipeline. The heat exchange is used to raise the temperature of the nitrogen gas returning to the molten salt tank from the inlet pipeline, ensuring that the nitrogen gas returning to the molten salt tank is high-temperature nitrogen gas, so as to facilitate the recycling of high-temperature nitrogen gas.

[0031] In one optional embodiment, the molten salt energy storage system further includes:

[0032] A deaerator is installed in the water pipeline to remove dissolved oxygen from the water in the water pipeline.

[0033] Beneficial effects: The deaerator installed in the water pipeline is used to remove dissolved oxygen from the water flowing through the pipeline, preventing equipment corrosion in the molten salt energy storage system.

[0034] In one optional embodiment, the molten salt energy storage system further includes an electric heater and / or a heat source pipeline;

[0035] The electric heater is at least partially disposed in the molten salt tank and is used to heat the low-temperature molten salt;

[0036] The heat source pipeline is at least partially heat-exchangeable in the molten salt tank, so that the high-temperature heat exchange medium in the heat source pipeline exchanges heat with the low-temperature molten salt in the molten salt tank to heat the low-temperature molten salt.

[0037] Beneficial effects: Electric heaters and heat source pipelines can be used to heat low-temperature molten salt, thereby flexibly supplementing the heat in the molten salt tank and ensuring the stability of the energy storage temperature of the molten salt energy storage system. Attached Figure Description

[0038] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of a molten salt energy storage system provided by the present invention.

[0040] Explanation of reference numerals in the attached figures:

[0041] 1. Molten salt vessel; 101. Inner cavity; 102. Outlet; 103. Inlet;

[0042] 2. Blowering device; 201. Jet nozzle; 202. Drainage pipe;

[0043] 3. First heat exchanger;

[0044] 4. Compressor;

[0045] 5. Second heat exchanger;

[0046] 6. Third heat exchanger;

[0047] 7. Deaerator;

[0048] 8. Electric heater;

[0049] 9. Safety relief valve;

[0050] L1, nitrogen circulation line; L11, exhaust line; L12, intake line;

[0051] L2, water pipe;

[0052] L3, heat source pipeline. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all embodiments. 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.

[0054] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0055] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0056] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0057] The following is combined Figure 1 The following describes embodiments of the present invention.

[0058] According to embodiments of the present invention, a molten salt energy storage system is provided, such as... Figure 1 As shown, it includes: molten salt tank 1, nitrogen circulation pipeline L1, turbulence device 2 and water pipeline L2.

[0059] Molten salt tank 1 has an inner cavity 101 and an outlet 102 and an inlet 103 connected to the inner cavity 101. The inner cavity 101 can store nitrogen and molten salt for energy storage. A nitrogen circulation pipeline L1 is connected between the outlet 102 and the inlet 103 to export nitrogen from the molten salt tank 1 through the outlet 102 and import it through the inlet 103 to nitrogen seal the molten salt. A flow disturbance device 2 is located in the inner cavity 101 and connected to the inlet 103. The flow disturbance device 2 includes a jet 201. The nitrogen introduced from the inlet 103 is exported through the jet 201 to disturb the molten salt. A water pipeline L2 is used to guide water. The water pipeline L2 is at least partially heat-exchangeable in the molten salt tank 1 so that the low temperature water in the water pipeline L2 exchanges heat with the high temperature molten salt in the molten salt tank 1 to convert the water into high temperature steam for energy release.

[0060] In the above embodiment, the turbulence device 2 is installed in the inner cavity 101 of the molten salt tank 1. Nitrogen gas is discharged through the jet section 201 of the turbulence device 2 to form an upward flow of bubbles, thereby disturbing the molten salt in the molten salt tank 1, thereby enhancing the fluidity of the molten salt in the molten salt tank 1, improving the heat exchange effect between the molten salt and the heating and heat release units in the molten salt tank 1, improving the heat transfer efficiency of the molten salt, and improving the heat exchange effect between the energy release stage and the water in the water pipe L2. At the same time, it also improves the uniformity of nitrogen sealing.

[0061] Specifically, such as Figure 1 As shown, the inner cavity 101 of the molten salt tank 1 can store molten salt. The molten salt stores energy in the form of thermal energy, that is, during off-peak or peak periods, the molten salt is heated to high-temperature molten salt by a heating unit for energy storage. During peak or off-peak periods, heat is released, that is, softened water is introduced into the water pipe L2, and the low-temperature softened water in the water pipe L2 exchanges heat with the high-temperature molten salt in the molten salt tank 1 to convert the softened water into high-temperature steam for energy release. The high-temperature steam can then be used for power generation or heating. In this embodiment, a portion of the water pipe L2 extends into the molten salt tank 1 to facilitate heat exchange between the low-temperature softened water and the high-temperature molten salt in the molten salt tank 1.

[0062] Furthermore, such as Figure 1 As shown, the inner cavity 101 of the molten salt tank 1 can also store nitrogen gas for nitrogen sealing. Nitrogen gas in the molten salt tank 1 is discharged from the outlet 102 and introduced into the inlet 103 via the nitrogen circulation pipeline L1, i.e., nitrogen gas is injected into the molten salt system for nitrogen sealing, thus preventing oxygen from directly contacting the molten salt and avoiding the decomposition and deterioration of the molten salt in an oxygen environment. Simultaneously, in this embodiment, the nitrogen gas introduced into the molten salt tank 1 via the nitrogen circulation pipeline L1 through the inlet 103, i.e., returning to the molten salt tank 1, works in conjunction with the jet section 201 of the turbulence device 2 to form rising bubbles from the discharged nitrogen gas, thereby agitating the molten salt in the molten salt tank 1 and enhancing the fluidity of the molten salt within the molten salt tank 1, achieving multiple uses of nitrogen gas.

[0063] It should be noted that in this embodiment, the low-temperature water in the water pipe L2 exchanges heat with the high-temperature molten salt in the molten salt tank 1. The low temperature and high temperature are relative temperatures rather than absolute temperatures. That is, the temperature of the molten salt in the molten salt tank 1 is relatively higher than the temperature of the softened water in the water pipe L2, and heat exchange can be achieved between the two.

[0064] Furthermore, such as Figure 1 As shown, in this embodiment, the outlet 102 for exporting nitrogen gas from the molten salt tank 1 to the nitrogen circulation pipeline L1 is located on the top plate of the molten salt tank 1, and the inlet 103 for importing nitrogen gas from the nitrogen circulation pipeline L1 into the molten salt tank 1 is located on the side of the molten salt tank 1 and is positioned near the bottom of the molten salt tank 1, thereby improving the nitrogen circulation efficiency. A nitrogen purification device is provided at the top of the inner cavity 101 of the molten salt tank 1 to prevent nitrogen gas from carrying some molten salt out of the molten salt tank 1 when the nitrogen content is high.

[0065] In some embodiments, such as Figure 1 As shown, the jet section 201 is configured as a nozzle, through which nitrogen gas introduced by the inlet 103 is radially guided to the molten salt.

[0066] In the above embodiment, the jet unit 201 is configured as a nozzle so that the nitrogen introduced by the inlet 103 can be radially guided to the molten salt, thereby increasing the range of nitrogen guiding the molten salt and thus enhancing the range of nitrogen disturbance to the molten salt in the molten salt tank 1.

[0067] Specifically, such as Figure 1 As shown, when the jet section 201 is configured as a nozzle, the nitrogen introduced by the inlet 103 forms a radial nitrogen gas flow through the pressurization of the nozzle. The radial nitrogen gas flow increases the contact area between the nitrogen and the molten salt, thereby improving the range of nitrogen guiding the molten salt.

[0068] Furthermore, the location of the jet unit 201 is not limited in this embodiment. In one embodiment, the jet unit 201 is directly disposed on the side or bottom surface of the molten salt tank 1; in another embodiment, the jet unit 201 is disposed on the gas guiding device communicating with the inlet 103.

[0069] In some embodiments, such as Figure 1 As shown, in a preferred embodiment, the turbulence device 2 further includes a diversion pipe 202, which is connected to the nitrogen circulation pipeline L1 at the inlet 103, and the jet part 201 is provided on the diversion pipe 202.

[0070] In the above embodiment, the jet 201 is provided with an installation position by the drainage pipe 202 located in the inner cavity 101 and connected to the inlet 103 of the molten salt tank 1, so that the jet 201 is located in the internal space of the inner cavity 101, thereby allowing the nitrogen gas discharged by the jet 201 to fully disturb the molten salt.

[0071] Specifically, such as Figure 1 As shown, at least a portion of the drain pipe 202 is fixed to the side wall of the molten salt tank 1 so that the air inlet end of the drain pipe 202 is connected to the inlet 103 opened on the side wall of the molten salt tank 1; the air outlet end of the drain pipe 202 is the jet part 201 connected to the inner cavity 101 of the molten salt tank 1 so that nitrogen gas flows back to the inner cavity 101 to realize nitrogen gas recycling.

[0072] In some embodiments, such as Figure 1 As shown, the drainage pipe 202 is located near the bottom of the molten salt tank 1.

[0073] In the above embodiment, since the molten salt is mostly located at the bottom of the molten salt tank 1 due to gravity, the drainage pipe 202 is set close to the bottom of the molten salt tank 1 so that the jet 201 is set close to the bottom of the molten salt tank 1, thereby improving the sufficiency of the nitrogen gas discharged by the jet 201 disturbing the molten salt.

[0074] Specifically, such as Figure 1 As shown, the jetting direction of the jetting section 201 provided in the drainage pipe 202 is toward the top of the molten salt tank 1.

[0075] In some embodiments, the drainage pipe 202 is arranged in a coiled shape so that the projection of the drainage pipe 202 in the direction of the bottom of the molten salt tank 1 covers the bottom of the molten salt tank 1, and a plurality of jets 201 are evenly spaced on the drainage pipe 202.

[0076] In the above embodiment, the drainage pipe 202 is arranged in a coiled shape so that the distribution range of the drainage pipe 202 covers the entire cross-section of the molten salt tank 1. When multiple jets 201 are evenly spaced on the drainage pipe 202, the distribution range of the multiple jets 201 covers the entire cross-section of the molten salt tank 1, thereby further improving the sufficiency of the nitrogen gas vented by the jets 201 disturbing the molten salt.

[0077] Specifically, the drainage pipe 202 is constructed as a spirally coiled section of curved pipe, and multiple jet units 201 are evenly spaced along the spiral direction of the curved pipe on the drainage pipe 202.

[0078] As an alternative implementation method, such as Figure 1 As shown, the drainage pipe 202 is constructed as a straight pipe with a straight line, and multiple jets 201 are evenly spaced along the extension direction of the straight pipe in the drainage pipe 202.

[0079] In some embodiments, such as Figure 1 As shown, the molten salt energy storage system also includes a temperature control component.

[0080] The temperature control component is located between the water circulation pipeline L2 and the nitrogen circulation pipeline L1. The temperature control component is used to exchange heat between the high-temperature nitrogen gas in the nitrogen circulation pipeline L1 and the low-temperature water in the water circulation pipeline L2 in order to preheat the water in the water circulation pipeline L2.

[0081] In the above embodiment, a temperature control component is installed between the water supply pipeline L2 and the nitrogen circulation pipeline L1. This utilizes the heat exchange between high-temperature nitrogen and low-temperature softened water to preheat the softened water in the water supply pipeline L2, avoiding thermal stress problems caused by excessive temperature differences when the molten salt energy storage system releases energy, thus enhancing equipment safety. Furthermore, it fully utilizes the relatively high-temperature heat in the nitrogen circulation to improve the nitrogen's heat recovery efficiency.

[0082] Specifically, such as Figure 1 As shown, the temperature control component is constructed as one or more heat exchangers that are heat-exchangeably installed between the water supply pipeline L2 and the nitrogen circulation pipeline L1. During peak or off-peak periods, heat is released by introducing softened water into the water supply pipeline L2. The low-temperature softened water in the water supply pipeline L2 exchanges heat with the high-temperature molten salt in the molten salt tank 1. However, the low temperature of the softened water would create an excessive temperature difference with the high-temperature molten salt. Therefore, the softened water in the water supply pipeline L2 is preheated by exchanging heat between high-temperature nitrogen and the low-temperature softened water, thus avoiding thermal stress problems caused by excessive temperature differences when the molten salt energy storage system releases energy.

[0083] It should be noted that in this embodiment, the high-temperature nitrogen in the nitrogen circulation pipeline L1 exchanges heat with the low-temperature water in the water passage pipeline L2. The low and high temperatures are relative temperatures rather than absolute temperatures. That is, the temperature of the nitrogen in the nitrogen circulation pipeline L1 is relatively higher than the temperature of the softened water in the water passage pipeline L2, and heat exchange can be achieved between the two.

[0084] In some embodiments, such as Figure 1 As shown, the temperature control component includes: a first heat exchanger 3.

[0085] The first heat exchanger 3 is heat-exchangeably installed between the water pipeline L2 and the nitrogen circulation pipeline L1 to preheat the water in the water pipeline L2.

[0086] In the above embodiment, the softened water in the water pipe L2 is preheated by a first heat exchanger 3 that is heat-exchangeably disposed between the water pipe L2 and the nitrogen circulation pipe L1. The structure is simple and the heat exchange is highly efficient.

[0087] Specifically, such as Figure 1 As shown, the first heat exchanger 3 is located upstream of the water pipeline L2 and the nitrogen circulation pipeline L1.

[0088] In some embodiments, such as Figure 1 As shown, the temperature control assembly also includes: compressor 4 and second heat exchanger 5.

[0089] The compressor 4 is located in the nitrogen circulation pipeline L1 and downstream of the first heat exchanger 3, and is used to compress the low-temperature nitrogen gas after heat exchange into high-temperature nitrogen gas; the second heat exchanger 5 is located downstream of the compressor 4 and is heat-exchangeably located between the water pipeline L2 and the nitrogen circulation pipeline L1, so as to preheat the water in the water pipeline L2.

[0090] In the above embodiment, the second heat exchanger 5, which is heat-exchangeably installed between the water pipeline L2 and the nitrogen circulation pipeline L1, works in conjunction with the compressor 4 to achieve secondary preheating of the softened water in the water pipeline L2. This allows the softened water in the water pipeline L2 to be preheated multiple times, enabling graded recovery and utilization of heat, reducing heat waste, and improving the overall thermal efficiency of the molten salt energy storage system.

[0091] Specifically, such as Figure 1 As shown, after the first preheating, the temperature of the nitrogen in the nitrogen circulation pipeline L1 decreases. The compressor 4 compresses the low-temperature nitrogen after heat exchange into high-temperature nitrogen, so that the temperature of the nitrogen flowing through the second heat exchanger 5 is higher than the temperature of the softened water flowing through the second heat exchanger 5, so as to achieve secondary preheating of the softened water.

[0092] It should be noted that in this embodiment, the compressor 4 is used to compress the low-temperature nitrogen gas after heat exchange into high-temperature nitrogen gas. The low temperature and high temperature are relative temperatures rather than absolute temperatures, that is, the temperature of the nitrogen gas downstream of the compressor 4 is relatively higher than the temperature of the nitrogen gas upstream of the compressor 4.

[0093] In some embodiments, such as Figure 1 As shown, the nitrogen circulation pipeline L1 includes an outlet pipeline L11 located upstream of the temperature control component and an inlet pipeline L12 located downstream of the temperature control component.

[0094] The molten salt energy storage system also includes: a third heat exchanger 6.

[0095] The third heat exchanger 6 is heat-exchangeably located between the outlet pipe L11 and the inlet pipe L12. It is used to exchange heat between the high-temperature nitrogen in the outlet pipe L11 and the low-temperature nitrogen in the inlet pipe L12, so as to raise the temperature of the nitrogen flowing back to the molten salt tank 1 from the inlet pipe L12.

[0096] In the above embodiment, after the nitrogen gas in the nitrogen circulation pipeline L1 exchanges heat with the softened water through the temperature control component, the nitrogen temperature in the upstream outlet pipeline L11 of the nitrogen circulation pipeline L1 is higher than the nitrogen temperature in the downstream inlet pipeline L12 of the nitrogen circulation pipeline L1. Therefore, a third heat exchanger 6 is set between the outlet pipeline L11 and the inlet pipeline L12. The nitrogen gas returning from the inlet pipeline L12 to the molten salt tank 1 is heated by heat exchange to ensure that the nitrogen gas returning to the molten salt tank 1 is high-temperature nitrogen gas, so as to facilitate the recycling of high-temperature nitrogen gas.

[0097] Specifically, such as Figure 1As shown, after the high-temperature nitrogen gas discharged from the outlet 102 in the molten salt tank 1 and the nitrogen gas introduced into the molten salt tank 1 from the inlet 103 are exchanged through the third heat exchanger 6, the temperature of the nitrogen gas flowing to the first heat exchanger 3 in the temperature control component is lower than the temperature of the nitrogen gas before heat exchange through the third heat exchanger 6, but the temperature is still higher than the temperature of the softened water introduced into the water pipe L2. Therefore, it does not affect the heat exchange between the nitrogen gas flowing through the temperature control component in the nitrogen circulation pipe L1 and the low-temperature softened water introduced into the water pipe L2, and thus does not affect the preheating of the softened water.

[0098] As an alternative implementation, instead of using the third heat exchanger 6 to exchange heat between the high-temperature nitrogen in the outlet pipe L11 and the low-temperature nitrogen in the inlet pipe L12 to raise the temperature of the nitrogen returning to the molten salt tank 1, a pipe heating device can be installed downstream of the second heat exchanger 5 in the nitrogen circulation pipe L1 to directly heat the low-temperature nitrogen downstream of the second heat exchanger 5 to raise the temperature of the nitrogen returning to the molten salt tank 1.

[0099] It should be noted that in this embodiment, the high-temperature nitrogen in the outlet pipe L11 exchanges heat with the low-temperature nitrogen in the inlet pipe L12. The low and high temperatures are relative temperatures rather than absolute temperatures. That is, the temperature of the nitrogen in the outlet pipe L11 upstream of the third heat exchanger 6 is relatively higher than the temperature of the nitrogen in the inlet pipe L12 upstream of the third heat exchanger 6, and heat exchange can be achieved between the two.

[0100] In some embodiments, such as Figure 1 As shown, the molten salt energy storage system also includes: a deaerator 7.

[0101] The deaerator 7 is installed in the water passage L2 and is used to remove dissolved oxygen from the water flowing through the water passage L2.

[0102] In the above embodiment, the deaerator 7 installed in the water passage L2 is used to remove dissolved oxygen from the water flowing through the water passage L2 to prevent equipment corrosion in the molten salt energy storage system.

[0103] Specifically, such as Figure 1 As shown, in this embodiment, the deaerator 7 is located downstream of the second heat exchanger 5. The softened water that has been preheated twice can have dissolved oxygen removed by the deaerator 7.

[0104] In some embodiments, such as Figure 1 As shown, the molten salt energy storage system also includes an electric heater 8 and / or a heat source pipeline L3.

[0105] The electric heater 8 is at least partially located in the molten salt tank 1 for heating the low-temperature molten salt; the heat source pipeline L3 is at least partially heat-exchangeably located in the molten salt tank 1 so that the high-temperature heat exchange medium in the heat source pipeline L3 exchanges heat with the low-temperature molten salt in the molten salt tank 1 to heat the low-temperature molten salt.

[0106] In the above embodiment, the electric heater 8 and the heat source pipeline L3 can both be used to heat the low-temperature molten salt, thereby flexibly supplementing the heat in the molten salt tank 1 and ensuring the energy storage temperature of the molten salt energy storage system is stable.

[0107] Specifically, such as Figure 1 As shown, the heating portion of the electric heater 8 is located within the molten salt tank 1, and can specifically be a heating wire, heating rod, etc. A portion of the heat source pipeline L3 extends into the molten salt tank 1 to facilitate heat exchange between the high-temperature heat exchange medium and the low-temperature molten salt within the tank. The high-temperature heat exchange medium specifically includes high-temperature steam or high-temperature flue gas introduced into the heat source pipeline L3 from the outside. The opening and closing of the electric heater 8 and the heat source pipeline L3 are controlled according to operating conditions to ensure efficient operation, converting the low-temperature molten salt into high-temperature molten salt for storage in the molten salt tank 1 for energy storage.

[0108] It should be noted that in this embodiment, the high-temperature heat exchange medium in the heat source pipeline L3 exchanges heat with the low-temperature molten salt in the molten salt tank 1. The low temperature and high temperature are relative temperatures rather than absolute temperatures. That is, the temperature of the heat exchange medium in the heat source pipeline L3 is relatively higher than the temperature of the molten salt in the molten salt tank 1, and heat exchange can be achieved between the two.

[0109] It is understandable that only electric heater 8, only heat source pipe L3, or both electric heater 8 and heat source pipe L3 can be installed. Of course, one or more sets of electric heater 8 and heat source pipe L3 can be installed.

[0110] In some embodiments, such as Figure 1 As shown, the top of the molten salt tank 1 is equipped with a safety relief valve 9 to ensure the safe operation of the system.

[0111] In this embodiment, the highest temperature of the molten salt tank 1 during the energy storage stage is 560°C, and the lowest temperature during the energy release stage is 300°C; the temperature range of the nitrogen outlet 102 and inlet 103 in the molten salt tank 1 is 300°C-560°C.

[0112] Nitrogen gas flowing out of molten salt tank 1 is cooled to 100℃-200℃ after passing through the third heat exchanger 6 and then enters the first heat exchanger 3; nitrogen gas flowing out of the first heat exchanger 3 is cooled to about 40℃ and enters the compressor 4; nitrogen gas flowing out of the compressor 4 is cooled to 100℃-200℃ and enters the second heat exchanger 5; nitrogen gas flowing out of the second heat exchanger 5 is cooled to about 60℃ and enters the third heat exchanger 6; nitrogen gas flowing out of the third heat exchanger 6 is cooled to about 300℃ and then flows back into molten salt tank 1.

[0113] The softened water flowing into the water pipe L2 is at room temperature. After passing through the first heat exchanger 3, the temperature rises to 40℃-50℃ and enters the second heat exchanger 5. The softened water flowing out of the second heat exchanger 5 has a temperature of 60℃-100℃ and enters the deaerator 7. The softened water flowing out of the deaerator 7 has a temperature of about 160℃ and then enters the water pipe L2, which is located inside the molten salt tank 1. After exchanging heat with the molten salt, the softened water is used as steam at 300℃-400℃.

[0114] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by this application.

Claims

1. A molten salt energy storage system, characterized in that, include: The molten salt tank (1) is provided with an inner cavity (101) and an outlet (102) and an inlet (103) communicating with the inner cavity (101). The inner cavity (101) is capable of storing nitrogen and high-temperature molten salt for energy storage. A nitrogen circulation pipeline (L1) is connected between the outlet (102) and the inlet (103) for exporting nitrogen gas from the molten salt tank (1) through the outlet (102) and importing it through the inlet (103) to nitrogen seal the molten salt. A flow disturbance device (2) is provided in the inner cavity (101) and communicates with the inlet (103). The flow disturbance device (2) includes a jet section (201), through which nitrogen introduced by the inlet (103) is discharged to disturb the molten salt. A water pipe (L2) is used to guide water. The water pipe (L2) is at least partially heat-exchangeably installed in the molten salt tank (1) so that the low temperature water in the water pipe (L2) exchanges heat with the high temperature molten salt in the molten salt tank (1) to convert the water into high temperature steam for energy release. The molten salt energy storage system further includes a temperature control component, which comprises: The first heat exchanger (3) is heat-exchangeably disposed between the water pipeline (L2) and the nitrogen circulation pipeline (L1) to preheat the water in the water pipeline (L2) once. The compressor (4) is located in the nitrogen circulation pipeline (L1) and downstream of the first heat exchanger (3), and is used to compress the low-temperature nitrogen gas after heat exchange into high-temperature nitrogen gas. The second heat exchanger (5) is located downstream of the compressor (4) and is heat-exchangeably disposed between the water pipeline (L2) and the nitrogen circulation pipeline (L1) to preheat the water in the water pipeline (L2) for a second time.

2. The molten salt energy storage system according to claim 1, characterized in that, The jet section (201) is configured as a nozzle, through which nitrogen gas introduced by the inlet (103) is radially guided to the molten salt.

3. The molten salt energy storage system according to claim 1 or 2, characterized in that, The turbulence device (2) further includes a flow pipe (202), which is connected to the nitrogen circulation pipeline (L1) at the inlet (103), and the jet part (201) is located in the flow pipe (202).

4. The molten salt energy storage system according to claim 3, characterized in that, The drainage pipe (202) is located near the bottom of the molten salt tank (1); And / or, the drainage pipe (202) is arranged in a coiled shape so that the projection of the drainage pipe (202) in the direction of the bottom of the molten salt tank (1) covers the bottom of the molten salt tank (1), and a plurality of the jets (201) are evenly spaced on the drainage pipe (202).

5. The molten salt energy storage system according to any one of claims 1, 2, and 4, characterized in that, The temperature control component is located between the water passage (L2) and the nitrogen circulation passage (L1). The temperature control component is used to exchange heat between the high-temperature nitrogen gas in the nitrogen circulation passage (L1) and the low-temperature water in the water passage (L2) to preheat the water in the water passage (L2).

6. The molten salt energy storage system according to claim 5, characterized in that, The nitrogen circulation pipeline (L1) includes an outlet pipeline (L11) located upstream of the temperature control component and an inlet pipeline (L12) located downstream of the temperature control component. The molten salt energy storage system also includes: The third heat exchanger (6) is heat-exchangeably disposed between the outlet pipe (L11) and the inlet pipe (L12) for exchanging heat between the high-temperature nitrogen in the outlet pipe (L11) and the low-temperature nitrogen in the inlet pipe (L12) to raise the temperature of the nitrogen flowing back to the molten salt tank (1) from the inlet pipe (L12).

7. The molten salt energy storage system according to any one of claims 1, 2, 4, and 6, characterized in that, The molten salt energy storage system also includes: A deaerator (7) is installed in the water passage (L2) to remove dissolved oxygen from the water in the water passage (L2).

8. The molten salt energy storage system according to any one of claims 1, 2, 4, and 6, characterized in that, The molten salt energy storage system also includes an electric heater (8) and / or a heat source pipeline (L3). The electric heater (8) is at least partially disposed in the molten salt tank (1) for heating low-temperature molten salt; The heat source pipeline (L3) is at least partially heat-exchangeably disposed in the molten salt tank (1), so that the high-temperature heat exchange medium in the heat source pipeline (L3) exchanges heat with the low-temperature molten salt in the molten salt tank (1) to heat the low-temperature molten salt.

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