Energy storage system based on fused salt

Abstract

The invention relates to an energy storage system based on fused salt, and relates to the technical field of fused salt energy storage. The system comprises a heat supply unit, a heating unit, a fused salt energy storage unit, a steam generation unit and a hot water generation unit, the heat supply unit is used for providing heat energy for the heating unit; the heating unit is used for heating the molten salt working medium in the molten salt energy storage unit according to the heat energy provided by the heat supply unit so as to store the heat energy in the molten salt energy storage unit; the fused salt energy storage unit is used for storing a fused salt working medium and sequentially transmitting heat energy stored in the heated fused salt working medium to the steam generation unit and the hot water generation unit; the steam generation unit is used for generating steam at a first target temperature according to the heat energy transmitted by the fused salt energy storage unit and transmitting the residual heat energy in the fused salt working medium to the hot water generation unit; the hot water generating unit is used for generating hot water at the second target temperature according to the residual heat energy transmitted by the steam generating unit. The method can improve the energy utilization rate.

Description

Technical Field

[0001] This application relates to the field of molten salt energy storage technology, and in particular to an energy storage system based on molten salt. Background Technology

[0002] Industrial production processes generate a large amount of waste heat resources. This waste heat is usually at a high temperature and has a certain energy quality. However, most of the industrial waste heat is not fully utilized. Direct discharge not only wastes energy but also causes thermal pollution to the environment.

[0003] Molten salt energy storage technology, as a highly efficient energy storage method, has advantages such as high thermal density, low cost, and long lifespan, and can effectively solve the problem of energy mismatch in time and space. However, current molten salt energy storage systems have not fully utilized the stored energy, and the energy utilization rate needs to be improved. Summary of the Invention

[0004] Therefore, it is necessary to provide a molten salt-based energy storage system that can improve the energy utilization rate in molten salt energy storage systems, addressing the aforementioned technical problems.

[0005] In a first aspect, this application provides an energy storage system based on molten salt, comprising: a heating unit, a heating unit, a molten salt energy storage unit, a steam generation unit, and a hot water generation unit;

[0006] Heating unit, used to provide heat energy to heating unit;

[0007] A heating unit is used to heat the molten salt working medium in the molten salt energy storage unit according to the heat energy provided by the heating unit, so as to store the heat energy in the molten salt energy storage unit.

[0008] The molten salt energy storage unit is used to store molten salt working fluid and sequentially transfer the thermal energy stored in the heated molten salt working fluid to the steam generation unit and the hot water generation unit.

[0009] The steam generation unit is used to generate steam at the first target temperature based on the heat energy transferred from the molten salt energy storage unit, and to transfer the remaining heat energy in the molten salt working medium to the hot water generation unit.

[0010] A hot water generating unit is used to generate hot water at a second target temperature based on the residual heat energy transferred from the steam generating unit; the second target temperature is lower than the first target temperature.

[0011] In one embodiment, the molten salt energy storage unit includes: a low-temperature molten salt tank and a high-temperature molten salt tank; the low-temperature molten salt tank is used to store molten salt working fluid at a first preset temperature; the high-temperature molten salt tank is used to store molten salt working fluid heated to a second preset temperature, and to transport the molten salt working fluid at the second preset temperature to a steam generation unit, so as to transfer the heat energy stored in the molten salt working fluid at the second preset temperature to the steam generation unit; the steam generation unit is specifically used to generate steam based on the heat energy stored in the molten salt working fluid at the second preset temperature, and when the temperature of the molten salt working fluid at the second preset temperature reaches a third preset temperature, to transport the molten salt working fluid at the third preset temperature to a hot water generation unit, so as to transfer the heat energy stored in the molten salt working fluid at the third preset temperature to the hot water generation unit; wherein, the third preset temperature is lower than the second preset temperature and higher than the first preset temperature; the hot water generation unit is specifically used to generate hot water based on the heat energy stored in the molten salt working fluid at the third preset temperature.

[0012] In one embodiment, the molten salt energy storage unit further includes: at least two high-temperature molten salt pumps; the at least two high-temperature molten salt pumps are used to pump molten salt working medium at a second preset temperature stored in the high-temperature molten salt tank, so as to deliver the molten salt working medium at the second preset temperature to the steam generation unit.

[0013] In one embodiment, the system further includes: a molten salt recovery unit; the molten salt recovery unit is used to transport the molten salt working medium at the first preset temperature to a cryogenic molten salt tank when the temperature of the molten salt working medium at the third preset temperature drops to the first preset temperature.

[0014] In one embodiment, the molten salt recovery unit is further configured to: preheat the molten salt working medium stored in the low-temperature molten salt tank at a first preset temperature using the remaining airflow at a fourth preset temperature in the heating unit; the fourth preset temperature is higher than the first preset temperature.

[0015] In one embodiment, the molten salt recovery unit includes: at least two cryogenic molten salt pumps; at least two cryogenic molten salt pumps are used to pump molten salt working fluid at a third preset temperature to the molten salt energy storage unit.

[0016] In one embodiment, the system further includes: a first control unit and a second control unit; the first control unit is used to control the steam generation process of the steam generation unit; the second control unit is used to control the hot water generation process of the hot water generation unit.

[0017] In one embodiment, the system further includes: a power generation unit and a steam replenishment unit; the power generation unit is used to generate electricity based on steam; the steam replenishment unit is used to adjust the amount of steam supplied by the evaporation unit to the power generation unit.

[0018] In one embodiment, the heat energy supplied by the heating unit to the heating unit is obtained by converting at least one of the following energy sources: radiant energy, solar energy, and wind energy.

[0019] In one embodiment, the hot water generating unit includes: a cold water tank, a hot water tank, and a heat exchanger; the cold water tank is used to store cold water at a third target temperature; the third target temperature is lower than a second target temperature; the heat exchanger is used to exchange heat with the cold water to transfer residual heat energy to the cold water to generate hot water; and the hot water tank is used to store hot water.

[0020] The aforementioned molten salt-based energy storage system generates steam at a first target temperature using a steam generation unit based on the heat energy transferred from the molten salt energy storage unit, and transfers the remaining heat energy in the molten salt working medium to a hot water generation unit. The hot water generation unit then generates hot water at a second target temperature based on the remaining heat energy transferred from the steam generation unit. This allows for the tiered utilization of heat energy in the molten salt energy storage system, i.e., first using the heat energy in the molten salt energy storage system to generate high-temperature steam, and then using the remaining heat energy to generate medium-temperature hot water. This process fully utilizes the heat energy in the molten salt energy storage system and improves energy efficiency. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of a molten salt-based energy storage system in one embodiment;

[0023] Figure 2 This is a schematic diagram of the structure of a molten salt-based energy storage system in another embodiment;

[0024] Figure 3 This is a schematic diagram of the structure of a molten salt-based energy storage system in another embodiment.

[0025] Reference numerals: 1. Wind power generation system; 2. Photovoltaic power generation system; 3. Heater; 4. Industrial waste heat recovery system; 5. Mirror factory; 6. Heat absorption tower; 7. High-temperature molten salt tank; 8. Low-temperature molten salt tank; 9. First low-temperature molten salt pump; 10. Second low-temperature molten salt pump; 11. First high-temperature molten salt pump; 12. Second high-temperature molten salt pump; 13. First control pipeline; 14. Second control pipeline; 15. Evaporator; 16. Heat exchanger; 17. Hot water tank; 18. Cold water tank; 19. First pump body; 20. Second pump body; 21. Deaerator; 22. Make-up steam boiler; 23. Steam turbine power generation system; 24. Water storage tank; 25. User hot water end; 26. User cold water end; 27. Fourth pump body. Detailed Implementation

[0026] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0027] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and 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, and therefore should not be construed as a limitation of this application.

[0028] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0029] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0030] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0031] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0032] See Figure 1 , Figure 1 A schematic diagram of a molten salt-based energy storage system according to an embodiment of this application is shown. The molten salt-based energy storage system provided in an embodiment of this application includes a heating unit, a heating unit, a molten salt energy storage unit, a steam generation unit, and a hot water generation unit.

[0033] The heating unit is used to provide heat energy to the heating unit.

[0034] The heating unit is used to heat the molten salt working medium in the molten salt energy storage unit according to the heat energy provided by the heating unit, so as to store the heat energy in the molten salt energy storage unit.

[0035] The molten salt energy storage unit is used to store molten salt working fluid and sequentially transfer the thermal energy stored in the heated molten salt working fluid to the steam generation unit and the hot water generation unit.

[0036] The steam generation unit is used to generate steam at the first target temperature based on the heat energy transferred from the molten salt energy storage unit, and to transfer the remaining heat energy in the molten salt working medium to the hot water generation unit.

[0037] A hot water generating unit is used to generate hot water at a second target temperature based on the residual heat energy transferred from the steam generating unit; the second target temperature is lower than the first target temperature.

[0038] The working principle of the molten salt-based energy storage system provided in this application is as follows: The heating unit can provide heat energy to the heating unit. The heating unit heats the molten salt working medium in the molten salt energy storage unit according to the heat energy provided by the heating unit, so as to store the heat energy in the molten salt energy storage unit. When it is necessary to release heat energy, the molten salt energy storage unit first transfers the heat energy stored in the heated molten salt working medium to the steam generation unit. The steam generation unit generates steam at a first target temperature according to the heat energy transferred by the molten salt energy storage unit, and transfers the remaining heat energy in the molten salt working medium to the hot water generation unit. The hot water generation unit generates hot water at a second target temperature according to the remaining heat energy transferred by the steam generation unit.

[0039] The aforementioned molten salt-based energy storage system generates steam at a first target temperature using a steam generation unit based on the heat energy transferred from the molten salt energy storage unit, and transfers the remaining heat energy in the molten salt working medium to a hot water generation unit. The hot water generation unit then generates hot water at a second target temperature based on the remaining heat energy transferred from the steam generation unit. This allows for the tiered utilization of heat energy in the molten salt energy storage system, i.e., first using the heat energy in the molten salt energy storage system to generate high-temperature steam, and then using the remaining heat energy to generate medium-temperature hot water. This process fully utilizes the heat energy in the molten salt energy storage system and improves energy efficiency.

[0040] In one exemplary embodiment, the molten salt energy storage unit includes: a cryogenic molten salt tank and a high-temperature molten salt tank.

[0041] A cryogenic molten salt vessel is used to store molten salt working fluid at a first preset temperature.

[0042] A high-temperature molten salt tank is used to store molten salt working medium heated to a second preset temperature and to transport the molten salt working medium at the second preset temperature to a steam generation unit, so as to transfer the heat energy stored in the molten salt working medium at the second preset temperature to the steam generation unit.

[0043] The cryogenic molten salt tank can be connected to the inlet of the heating unit, and the high-temperature molten salt tank can be connected to the outlet of the heating unit. The molten salt working medium in the cryogenic molten salt tank can be transported to the heating unit through the inlet. The heating unit can heat the transported molten salt working medium according to the heat energy provided by the heating unit to obtain molten salt working medium at a second preset temperature. The molten salt working medium at the second preset temperature can be transported to the high-temperature molten salt tank through the outlet of the heating unit. When steam generation is required, the molten salt working medium at the second preset temperature stored in the high-temperature molten salt tank can be transported to the steam generation unit.

[0044] The steam generating unit is specifically used to generate steam at a first target temperature based on the thermal energy stored in the molten salt working medium at a second preset temperature, and to transport the molten salt working medium at the third preset temperature to the hot water generating unit when the temperature of the molten salt working medium at the second preset temperature drops to a third preset temperature, so as to transfer the thermal energy stored in the molten salt working medium at the third preset temperature to the hot water generating unit; wherein, the third preset temperature is lower than the second preset temperature and higher than the first preset temperature.

[0045] The hot water generation unit is specifically used to generate hot water at a second target temperature based on the thermal energy stored in the molten salt working medium at a third preset temperature.

[0046] When the temperature of the molten salt working medium at the second preset temperature drops to the third preset temperature, some heat energy is still stored in the molten salt working medium at the third preset temperature. This heat energy can be transferred to the hot water generation unit to generate hot water at the second target temperature.

[0047] In this embodiment, the thermal energy of the molten salt energy storage system is utilized in a cascade manner. That is, the thermal energy of the molten salt energy storage system is first used to generate high-temperature steam, and then the remaining thermal energy is used to generate medium-temperature hot water. The thermal energy of the molten salt energy storage system is fully utilized, and the energy utilization rate is improved.

[0048] In one exemplary embodiment, the molten salt energy storage unit further includes at least two high-temperature molten salt pumps.

[0049] At least two high-temperature molten salt pumps are used to pump molten salt working medium at a second preset temperature stored in the high-temperature molten salt tank, so as to deliver the molten salt working medium at the second preset temperature to the steam generation unit.

[0050] At least two high-temperature molten salt pumps can be deployed at the outlet of the high-temperature molten salt tank.

[0051] In one alternative embodiment, at least two high-temperature molten salt pumps can operate simultaneously. The combined operation of at least two high-temperature molten salt pumps can provide a higher head, meeting the requirements of long-distance transport or high-resistance conditions.

[0052] In one alternative embodiment, at least two high-temperature molten salt pumps can operate independently. By deploying at least two high-temperature molten salt pumps, the other pump can immediately take over if one pump fails, preventing the energy storage system from shutting down.

[0053] In one alternative embodiment, only one high-temperature molten salt pump can operate under low load conditions, while two pumps can operate in parallel under high load conditions to improve system response speed. Dynamically adjusting the number of operating high-temperature molten salt pumps based on system load (such as power generation and heat demand) allows for dynamic matching of load requirements and saves on the operating costs of the high-temperature molten salt pumps while ensuring normal system operation.

[0054] In one alternative embodiment, when the energy storage system is operating at 70%-90% load, a single high-temperature molten salt pump can be used to avoid a decrease in energy storage efficiency under low load conditions. When the energy storage system is operating at 50% load, the energy storage efficiency decreases by 15%. In this case, at least two high-temperature molten salt pumps can be used simultaneously to maintain overall efficiency.

[0055] In one alternative embodiment, a frequency converter can be used to adjust the speed of each high-temperature molten salt pump according to the flow demand, thereby further reducing energy consumption.

[0056] In one alternative embodiment, at least two high-temperature molten salt pumps can operate alternately, reducing the continuous operating time of a single pump, reducing wear, and extending equipment life.

[0057] In one alternative embodiment, at least two high-temperature molten salt pumps can operate simultaneously to reduce the risk of cavitation from a single pump and ensure stable molten salt delivery. In the event of a system failure (such as molten salt leakage), at least two high-temperature molten salt pumps can be quickly switched to maintain the operation of critical equipment.

[0058] In one exemplary embodiment, the above-described molten salt-based energy storage system further includes a molten salt recovery unit.

[0059] The molten salt recovery unit is used to transport the molten salt working medium at the first preset temperature to the cryogenic molten salt tank when the temperature of the molten salt working medium at the third preset temperature drops to the first preset temperature.

[0060] This embodiment enables the circulation of molten salt working fluid in the energy storage system, allowing the energy storage system to operate normally and improving the utilization rate of the molten salt working fluid.

[0061] In an exemplary embodiment, the molten salt recovery unit is further configured to: preheat the molten salt working medium stored in the low-temperature molten salt tank at a first preset temperature using the remaining airflow at a fourth preset temperature in the heating unit; the fourth preset temperature is higher than the first preset temperature.

[0062] The airflow at the fourth preset temperature can be understood as the remaining airflow after the heating unit heats the molten salt working medium previously stored in the low-temperature molten salt tank at the first preset temperature to the second preset temperature.

[0063] In one alternative embodiment, the molten salt recovery unit can extract and deliver the remaining gas flow at a fourth preset temperature to a cryogenic molten salt tank.

[0064] In this embodiment, by using the remaining airflow at the fourth preset temperature in the heating unit to preheat the molten salt working medium at the first preset temperature stored in the low-temperature molten salt tank, on the one hand, the heat energy of the airflow generated in the heating unit can be fully utilized to improve the heat energy utilization rate; on the other hand, the time to heat the molten salt working medium at the first preset temperature in the low-temperature molten salt tank to the second preset temperature can be shortened; and on the other hand, the heat energy consumption in the heating unit can be reduced.

[0065] In one exemplary embodiment, the molten salt recovery unit includes: at least two cryogenic molten salt pumps;

[0066] At least two cryogenic molten salt pumps are used to pump molten salt working fluid at a third preset temperature into the molten salt energy storage unit.

[0067] At least two cryogenic molten salt pumps can be deployed at the outlet of the cryogenic molten salt tank.

[0068] In one alternative embodiment, at least two cryogenic molten salt pumps can operate simultaneously. The combined operation of at least two cryogenic molten salt pumps can provide a higher head, meeting the requirements of long-distance transport or high-resistance conditions.

[0069] In one alternative embodiment, at least two cryogenic molten salt pumps can operate independently. By deploying at least two cryogenic molten salt pumps, the other pump can immediately take over if one fails, preventing the energy storage system from shutting down.

[0070] In one alternative embodiment, only one cryogenic molten salt pump can operate under low load conditions, while two pumps can operate in parallel under high load conditions to improve system response speed. Dynamically adjusting the number of operating cryogenic molten salt pumps based on system load (such as power generation and heat demand) allows for dynamic matching of load requirements and saves on operating costs of the cryogenic molten salt pumps while ensuring normal system operation.

[0071] In one alternative embodiment, when the energy storage system is operating at 70%-90% load, a single cryogenic molten salt pump can be used to avoid a decrease in energy storage efficiency under low load conditions. When the energy storage system is operating at 50% load, the energy storage efficiency decreases by 15%. In this case, at least two cryogenic molten salt pumps can be used simultaneously to maintain overall efficiency.

[0072] In one alternative embodiment, a frequency converter can be used to adjust the speed of each cryogenic molten salt pump according to the flow demand, thereby further reducing energy consumption.

[0073] In one alternative embodiment, at least two cryogenic molten salt pumps can operate alternately, reducing the continuous operating time of a single pump, reducing wear, and extending equipment life.

[0074] In one alternative embodiment, at least two cryogenic molten salt pumps can operate simultaneously to reduce the risk of cavitation from a single pump and ensure stable molten salt delivery. In the event of a system failure (such as molten salt leakage), at least two cryogenic molten salt pumps can be quickly switched to maintain the operation of critical equipment.

[0075] In one alternative embodiment, the cryogenic molten salt pump can also serve as a spare part for the high-temperature molten salt pump, reducing spare parts inventory costs.

[0076] In an exemplary embodiment, the above-described molten salt-based energy storage system further includes: a first control unit and a second control unit.

[0077] The first control unit is used to control the steam generation process of the steam generation unit.

[0078] The second control unit is used to control the hot water generation process of the hot water generation unit.

[0079] In one optional embodiment, the first control unit can be a first control conduit. The second control unit can be a second control conduit.

[0080] In one optional embodiment, the first control unit and the second control unit can operate independently. Either only the steam generation unit or only the hot water generation unit can operate, or both can operate simultaneously, improving the flexibility of thermal energy usage scenarios.

[0081] In one exemplary embodiment, the above-described molten salt-based energy storage system further includes a power generation unit and a steam replenishment unit.

[0082] A power generation unit used to generate electricity from steam.

[0083] The steam replenishment unit is used to regulate the amount of steam supplied by the evaporation unit to the power generation unit.

[0084] In one alternative embodiment, the steam replenishment unit may include a steam replenishment boiler.

[0085] This embodiment utilizes a supplementary steam unit to adjust the amount of steam supplied by the evaporation unit to the power generation unit, which can significantly improve the stability of steam parameters, reduce equipment losses, and improve system energy efficiency.

[0086] In one exemplary embodiment, the heating unit can be used to convert other forms of energy into heat energy and provide heat energy to the heating unit. The heating unit may include at least one of a solar thermal heating unit, a photovoltaic power generation unit, and a wind power generation unit.

[0087] The heat energy supplied by the heating unit to the heating unit is obtained by converting at least one of the following energy sources: radiant energy, solar energy, and wind energy.

[0088] The conversion of radiant energy into heat energy can be achieved through a solar thermal heating unit. In an optional embodiment, the solar thermal heating system may include a mirror field and an absorber tower. The mirror field is arranged around the absorber tower. The mirror field is used to reflect sunlight. The absorber tower is used to absorb the sunlight reflected by the mirror field, converting radiant energy into heat energy. The solar thermal heating unit is connected to a heating unit, and the solar thermal heating unit transfers the heat energy converted from radiant energy to the heating unit.

[0089] The conversion of solar energy into heat energy can be achieved through a photovoltaic power generation unit. In an optional embodiment, the photovoltaic power generation unit may include a photovoltaic panel unit. The photovoltaic panel unit is used to convert solar energy into electrical energy and then into heat energy. The photovoltaic power generation unit is connected to a heating unit, and the photovoltaic power generation unit transfers the heat energy converted from solar energy to the heating unit.

[0090] The conversion of wind energy into heat energy can be achieved through a wind power generation unit. In an optional embodiment, the wind power generation unit may include a wind turbine cluster. The wind turbine cluster is used to convert wind energy into electrical energy, and then into heat energy. The wind power generation unit is connected to a heating unit, and the wind power generation unit transfers the heat energy converted from wind energy to the heating unit.

[0091] In one exemplary embodiment, the hot water generation unit includes a cold water tank, a hot water tank, and a heat exchanger.

[0092] A cold water tank is used to store cold water at a third target temperature, which is lower than the second target temperature.

[0093] A heat exchanger is used to exchange heat with cold water to transfer excess heat energy to the cold water and generate hot water at a second target temperature.

[0094] A hot water tank is used to store hot water at a second target temperature.

[0095] This embodiment uses heat exchange to transfer surplus heat energy to cold water, generating hot water at a second target temperature. This allows for the full utilization of surplus heat energy and provides a stable heat source for scenarios such as residential heating and hotel hot water.

[0096] See Figure 2 , Figure 2A schematic diagram of a molten salt-based energy storage system according to another embodiment of this application is shown. The molten salt-based energy storage system in this embodiment includes: a multi-energy heating system, an industrial waste heat recovery system 4, and a molten salt energy storage system.

[0097] The molten salt energy storage system includes: a high-temperature molten salt tank 7 and a low-temperature molten salt tank 8.

[0098] The multi-energy heating system includes: a solar thermal heating system, a photovoltaic power generation system 2, a wind power generation system 1, and a heater 3.

[0099] The solar thermal heating system includes a mirror 5 and an absorber tower 6. The mirror 5 is arranged around the absorber tower 6. The inlet of the absorber tower 6 is connected to a low-temperature molten salt tank 8, and the outlet of the absorber tower 6 is connected to a high-temperature molten salt tank 7.

[0100] The photovoltaic power generation system 2 includes: a photovoltaic panel unit, which is connected to a heater 3.

[0101] The wind power generation system 1 includes: a group of wind turbines, which is connected to a heater 3.

[0102] The inlet of heater 3 is connected to the low-temperature molten salt tank 8, and the outlet of heater 3 is connected to the high-temperature molten salt tank 7.

[0103] The inlet of the industrial waste heat recovery system 4 is connected to the low-temperature molten salt tank 8, and the outlet of the industrial waste heat recovery system 4 is connected to the high-temperature molten salt tank 7.

[0104] The working principle of the molten salt-based energy storage system provided in this embodiment is as follows: When energy is abundant, the industrial waste heat recovery system 4, the solar thermal heating system, the photovoltaic power generation system 2, and the wind power generation system 1 operate simultaneously or separately, heating the low-temperature molten salt to a high-temperature state and storing it in the high-temperature molten salt tank 7. When energy needs to be released, the high-temperature molten salt flows out from the high-temperature molten salt tank 7, generates steam through the evaporator 15, and drives the steam turbine power generation system 23 to work, completing the energy release process. At the same time, the low-temperature molten salt, after releasing heat, returns to the low-temperature molten salt tank 8, waiting to be reheated.

[0105] In this embodiment, the heat dissipation inlet of the evaporator 15 is connected to the outlet of the high-temperature molten salt tank 7 via a high-temperature molten salt pipeline, allowing it to receive high-temperature molten salt from the tank 7. This high-temperature molten salt carries a large amount of heat energy into the evaporator, providing a heat source for subsequent heat exchange with the medium on the heated side. The heat dissipation outlet of the evaporator 15 is connected to the heat dissipation inlet of the heat exchanger 16 via a medium-temperature molten salt pipeline, allowing the output of the medium-temperature molten salt, which has cooled after heat exchange with the medium on the heated side in the evaporator 15, to continue releasing residual heat, thus achieving cascaded utilization of molten salt heat. The heat dissipation outlet of the heat exchanger 16 is connected to the inlet of the low-temperature molten salt tank 8 via a low-temperature molten salt pipeline, allowing the output of the low-temperature molten salt, which has further cooled after heat exchange with the medium on the heated side in the heat exchanger 16, to be stored in the low-temperature molten salt tank 8 for potential subsequent heating and recycling. The heated outlet of evaporator 15 is connected to a high-temperature steam pipeline, outputting high-temperature steam formed by the vaporization of water after absorbing heat from molten salt within evaporator 15. This high-temperature steam can be used for power generation, heating, or other industrial production processes, realizing the conversion of thermal energy into mechanical energy or other forms of energy. The heated inlet of evaporator 15 (e.g., a steam generator) is connected to the outlet of deaerator 21, receiving water that has undergone deoxygenation treatment by deaerator 21. Deoxygenation treatment removes oxygen and other gases from the water, preventing these gases from corroding the equipment within evaporator 15, ensuring the safe and stable operation of evaporator 15, and providing raw materials for the heating and vaporization of water. The inlet of deaerator 21 is connected to water storage tank 24. The heated inlet of heat exchanger 16 can be used to receive the medium to be heated (usually water or other fluids requiring heating). This medium absorbs heat released by molten salt within heat exchanger 16, achieving temperature increase or phase change (e.g., liquid to gas change). The heat exchanger 16's heat exchange outlet is connected to the inlet of the hot water tank 17, outputting the heated hot water (or heated medium) after absorbing heat from the molten salt to the hot water tank 17 for storage, so that it can be distributed and used according to actual needs (such as heating, industrial hot water, etc.). The outlet of the hot water tank 17 is connected to the user's hot water pipeline (connected to the user's hot water end 25), and the hot water tank 17 is connected to the water storage tank 24 through a water supply pipeline. The heat exchanger 16's heat exchange inlet is connected to the outlet of the cold water tank 18, and the inlet of the cold water tank 18 is connected to the user's cold water pipeline (connected to the user's cold water end 26).

[0106] In this embodiment, the efficiency of energy cascade utilization can be improved: molten salt energy storage systems typically store high-temperature molten salt (approximately 500-600℃), which is directly used to generate high-temperature steam (e.g., 400℃). After the molten salt temperature drops to a medium temperature (e.g., 200-300℃), the remaining heat is used to heat cold water to produce hot water (e.g., 80℃). High-temperature steam is suitable for power generation and industrial steam demand, while low-temperature hot water is suitable for heating and domestic hot water applications, avoiding the "over-capacity" problem caused by directly producing hot water from high-temperature molten salt. Through two-stage heat release, the sensible and latent heat of the molten salt are fully utilized, and the overall thermal efficiency of the system can be improved by 10%-15%.

[0107] In this embodiment, the two-stage heat release design of molten salt energy storage achieves efficient synergy between high-temperature steam production and medium-temperature hot water production through energy cascade utilization. This not only improves the system's economic efficiency but also enhances its ability to adapt to complex operating conditions. It is a key technology direction for future large-scale energy storage and multi-energy complementary systems.

[0108] In this embodiment, the evaporator 15 needs to withstand high temperature and high pressure, but only needs to handle the heat exchange between molten salt and steam, thus reducing design complexity. The heat exchanger 16 handles medium-temperature molten salt and cold water, significantly reducing material costs and pressure resistance requirements. Staged heat exchange reduces the high temperature and high pressure load on individual equipment, extends equipment life, and reduces maintenance frequency.

[0109] In this embodiment, the high-temperature steam pipeline is also connected to the supplementary steam boiler 22 via a branch line, and the inlet of the supplementary steam boiler 22 is connected to the outlet of the deaerator 21. Connecting the supplementary steam boiler 22 via a branch line can significantly improve the stability of steam parameters, reduce equipment losses, and improve system energy efficiency. The coupled design of the molten salt energy storage system and the supplementary steam boiler 22, through the cascade utilization of "high-temperature steam production and medium-temperature hot water production" combined with the dynamic adjustment of the supplementary steam boiler 22, achieves efficient and stable energy output.

[0110] In this embodiment, the pipeline between the cold water tank 18 and the heat exchanger 16 has a first pump body 19. The pipeline between the hot water tank 17 and the water storage tank 24 has a second pump body 20. The pipeline between the water storage tank 24 and the deaerator 21 is equipped with a third pump body. The pipeline between the deaerator 21 and the evaporator 15 is equipped with a fourth pump body 27.

[0111] In this embodiment, the high-temperature molten salt pipeline at the outlet of the high-temperature molten salt tank 7 has a first high-temperature molten salt pump 11 and a second high-temperature molten salt pump 12 connected in parallel. The low-temperature molten salt pipeline at the outlet of the low-temperature molten salt tank 8 has a first low-temperature molten salt pump 9 and a second low-temperature molten salt pump 10 connected in parallel.

[0112] In this embodiment, the industrial waste heat recovery system 4 uses the waste heat of high-temperature flue gas in the smelting furnace or heating furnace to preheat the low-temperature molten salt. The industrial waste heat recovery system 4 is connected to the heater 3.

[0113] In this embodiment, the photovoltaic array of the photovoltaic panel unit is installed on the top layer of the high-temperature molten salt tank 7, the low-temperature molten salt tank 8, the hot water tank 17, the cold water tank 18 and the heat absorption tower 6.

[0114] In this embodiment, the high-temperature molten salt tank 7 and the low-temperature molten salt tank 8 are arranged around the heat absorption tower 6.

[0115] In this embodiment, the wind turbine generator group is located on the outermost periphery of the entire system.

[0116] See Figure 3 , Figure 3 A schematic diagram of a molten salt-based energy storage system according to another embodiment of this application is shown. The molten salt-based energy storage system in this embodiment further includes a first control line 13 and a second control line 14, enabling independent control of the operation of the heat exchanger 16 and the evaporator 15. That is, this embodiment can operate either only the evaporator 15 or the heat exchanger 16, or both can operate simultaneously. Other structures of the molten salt-based energy storage system in this embodiment can be referred to. Figure 2 The molten salt-based energy storage system shown will not be described in detail here.

[0117] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A molten salt-based energy storage system, characterized in that, include: Heating unit, heating unit, molten salt energy storage unit, steam generation unit and hot water generation unit; The heating unit is used to provide heat energy to the heating unit; The heating unit is used to heat the molten salt working medium in the molten salt energy storage unit according to the heat energy provided by the heating unit, so as to store the heat energy in the molten salt energy storage unit; The molten salt energy storage unit is used to store the molten salt working medium and to sequentially transfer the thermal energy stored in the heated molten salt working medium to the steam generation unit and the hot water generation unit. The steam generation unit is used to generate steam at a first target temperature based on the heat energy transmitted by the molten salt energy storage unit, and to transmit the remaining heat energy in the molten salt working fluid to the hot water generation unit. The hot water generating unit is used to generate hot water at a second target temperature based on the residual heat energy transmitted by the steam generating unit; the second target temperature is lower than the first target temperature.

2. The system according to claim 1, characterized in that, The molten salt energy storage unit includes: a low-temperature molten salt tank and a high-temperature molten salt tank; The low-temperature molten salt tank is used to store molten salt working fluid at a first preset temperature; The high-temperature molten salt tank is used to store molten salt working medium heated to a second preset temperature, and to transport the molten salt working medium at the second preset temperature to the steam generation unit, so as to transfer the heat energy stored in the molten salt working medium at the second preset temperature to the steam generation unit; The steam generating unit is specifically used to generate steam based on the thermal energy stored in the molten salt working medium at the second preset temperature, and when the temperature of the molten salt working medium at the second preset temperature reaches the third preset temperature, to transport the molten salt working medium at the third preset temperature to the hot water generating unit, so as to transfer the thermal energy stored in the molten salt working medium at the third preset temperature to the hot water generating unit; wherein, the third preset temperature is lower than the second preset temperature and higher than the first preset temperature; The hot water generation unit is specifically used to generate the hot water based on the thermal energy stored in the molten salt working medium at the third preset temperature.

3. The system according to claim 2, characterized in that, The molten salt energy storage unit also includes: at least two high-temperature molten salt pumps; The at least two high-temperature molten salt pumps are used to pump the molten salt working medium at the second preset temperature stored in the high-temperature molten salt tank, so as to deliver the molten salt working medium at the second preset temperature to the steam generation unit.

4. The system according to claim 2, characterized in that, The system also includes: a molten salt recovery unit; The molten salt recovery unit is used to transport the molten salt working medium at the first preset temperature to the cryogenic molten salt tank when the temperature of the molten salt working medium at the third preset temperature drops to the first preset temperature.

5. The system according to claim 4, characterized in that, The molten salt recovery unit is further configured to: preheat the molten salt working medium at the first preset temperature stored in the low-temperature molten salt tank using the remaining airflow at the fourth preset temperature in the heating unit; the fourth preset temperature is higher than the first preset temperature.

6. The system according to claim 4, characterized in that, The molten salt recovery unit includes: at least two cryogenic molten salt pumps; The at least two cryogenic molten salt pumps are used to pump the molten salt working fluid at the third preset temperature into the molten salt energy storage unit.

7. The system according to any one of claims 1-6, characterized in that, The system further includes: a first control unit and a second control unit; The first control unit is used to control the steam generation process of the steam generation unit; The second control unit is used to control the hot water generation process of the hot water generating unit.

8. The system according to any one of claims 1-6, characterized in that, The system also includes: a power generation unit and a steam replenishment unit; The power generation unit is used to generate electricity based on the steam; The steam replenishment unit is used to adjust the amount of steam supplied by the evaporation generating unit to the power generation unit.

9. The system according to any one of claims 1-6, characterized in that, The heat energy supplied by the heating unit to the heating unit is obtained by converting at least one of the following energy sources: radiant energy, solar energy, and wind energy.

10. The system according to any one of claims 1-6, characterized in that, The hot water generation unit includes: a cold water tank, a hot water tank, and a heat exchanger; The cold water tank is used to store cold water at a third target temperature; the third target temperature is lower than the second target temperature. The heat exchanger is used to exchange heat with the cold water to transfer the residual heat energy to the cold water and generate the hot water; The hot water tank is used to store the hot water.

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