A molten salt single tank heat storage system with high-position molten salt tank

Abstract

The present invention discloses a molten salt single tank heat storage system with a high-position arrangement of a molten salt tank, comprising: a molten salt tank; a molten salt tank, which is arranged at a high position beside the molten salt tank and connected to the atmosphere, and whose bottom is connected to the bottom of the molten salt tank; a low-temperature molten salt unit, comprising a low-temperature molten salt pump installed on the top of the molten salt tank and a molten salt heating and conveying assembly arranged between the low-temperature molten salt pump and the molten salt tank; a high-temperature molten salt unit, comprising a high-temperature molten salt pump installed on the top of the molten salt tank and a molten salt heat release and conveying assembly arranged between the top of the molten salt tank and the bottom of the molten salt tank. The system setting of the present invention can not only meet the requirement that the increase in the height of the storage tank in the performance optimization design is not limited by the underwater shaft length and sealing problems of the molten salt pump, but also enable the entire system to work under normal pressure conditions, ensuring the safety and convenience of system operation and maintenance.

Description

Technical Field

[0001] The present invention relates to the technical field of molten salt heat storage, and more specifically, to a molten salt single-tank heat storage system with a molten salt tank arranged at a high position. Background Art

[0002] The molten salt heat storage system with mature commercial applications is a double tank system, that is, two large molten salt storage tanks are used to store high-temperature molten salt and low-temperature molten salt respectively. The double tank heat storage system occupies a large area, has high construction and maintenance costs, and is less economical. However, studies have shown that the fixed investment cost of a single tank molten salt heat storage system filled with solid materials can be reduced by 35% compared with a double tank molten salt heat storage system, and has therefore attracted widespread attention. The molten salt single tank heat storage system uses the phenomenon that the density of molten salt decreases with increasing temperature, and uses a molten salt tank to store and release heat. The high-temperature molten salt is in the upper part of the tank, and the low-temperature molten salt is in the lower part of the tank. There is a natural temperature stratification at the junction of high and low temperature molten salts, called the incline layer. In order to maintain the stability of the incline layer, it is necessary to increase the height-to-diameter ratio of the storage tank and other ways to increase the system's heat storage availability and improve the system's operating performance. That is, a "thin and tall" storage tank is more conducive to realizing incline layer heat storage.

[0003] However, for a single tank system, high and low temperature molten salt pumps are usually installed on the top of the tank. During normal operation, the suction port of the low temperature molten salt pump must remain submerged below the low temperature molten salt liquid level, that is, deep into the bottom of the tank. Considering factors such as vibration, operational safety, and economy, the actual application shaft length of the molten salt pump is limited. Therefore, the submerged length of the molten salt pump has become the most important technical condition limiting the design height of the molten salt tank. At present, the straight section height of commercially applied molten salt storage tanks does not exceed 16m. The straight section height of the thermocline tank using hot water as the heat storage medium can reach 40m. The height of the thermocline tank using molten salt as the heat storage medium will also be much higher than the current 16m application status.

[0004] In order to solve the limitation of the shaft length of the molten salt pump on the height of the molten salt tank and further improve the performance of the single-tank heat storage system, people have proposed a low-level layout technology of a molten salt tank, which is to set up a small molten salt tank at the ground level next to the large molten salt tank. It is connected to the bottom of the large tank through a connecting pipe, and the molten salt pump is installed on the top of the molten salt tank instead of the top of the tank, thereby solving the limitation of the shaft length of the molten salt pump on the height of the tank. This technology effectively reduces the submerged depth of the molten salt pump. However, this installation method makes the molten salt tank and molten salt pump bear the heavy pressure brought by the tank liquid level. When the tank height is further increased (refer to the large inclined temperature layer hot water storage tank) to improve the system performance, the operating pressure in the molten salt tank also increases linearly, which makes it difficult to solve the sealing problem of the pump. This technology limits the selection of the tank height due to the pump sealing problem. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention proposes a molten salt single-tank heat storage system with a high-position molten salt tank. The setting of this system can not only meet the requirement that the increase in the storage tank height in the performance optimization design is not limited by the underwater shaft length and sealing problems of the molten salt pump, but also enable the entire system to operate under normal pressure conditions, thereby ensuring the safety and convenience of system operation and maintenance.

[0006] The present invention provides a molten salt single tank heat storage system with a molten salt tank arranged at a high position, comprising:

[0007] Molten salt storage tanks;

[0008] The molten salt tank is arranged at a high position beside the molten salt storage tank and is connected to the atmosphere, and its bottom is connected to the bottom of the molten salt storage tank;

[0009] A low-temperature molten salt unit, comprising a low-temperature molten salt pump installed on the top of the molten salt tank and a molten salt heating and conveying assembly arranged between the low-temperature molten salt pump and the molten salt storage tank;

[0010] The high-temperature molten salt unit comprises a high-temperature molten salt pump installed on the top of the molten salt storage tank and a molten salt heat release and conveying component arranged between the top of the molten salt storage tank and the bottom of the molten salt storage tank.

[0011] According to an embodiment of a molten salt single-tank heat storage system with a high-position molten salt tank of the present invention, the molten salt in the molten salt storage tank is distributed as a high-temperature molten salt layer at the top, a thermocline layer in the middle and a low-temperature molten salt layer at the bottom, and the molten salt storage tank is vertically arranged on a storage tank foundation.

[0012] According to an embodiment of the molten salt single-tank heat storage system with a high-position molten salt tank of the present invention, the bottom of the molten salt storage tank is connected to the bottom of the molten salt tank through a connecting pipe, and a molten salt control valve is provided in the connecting pipe.

[0013] According to an embodiment of a molten salt single-tank heat storage system with a molten salt tank arranged at a high position according to the present invention, the molten salt single-tank heat storage system also includes a salt discharge unit, the salt discharge unit includes a salt discharge tank and a salt discharge pump arranged on the salt discharge tank, the salt discharge pump is connected to the molten salt storage tank through a return pipe, the salt discharge tank is respectively connected to the connecting pipe and the molten salt heat release and transportation component in the high-temperature molten salt unit through the salt discharge pipe, and molten salt control valves are provided in the return pipe and the salt discharge pipe.

[0014] According to an embodiment of a molten salt single-tank heat storage system with a high-positioned molten salt tank of the present invention, the molten salt tank is horizontally arranged and a vent connected to the atmosphere is provided on the top. The installation height of the molten salt tank is at the same horizontal position as the top height of the molten salt storage tank, and the liquid level in the molten salt tank is substantially consistent with the liquid level in the molten salt storage tank.

[0015] According to an embodiment of a molten salt single-tank heat storage system with a high-position molten salt tank of the present invention, the molten salt heating and conveying assembly in the low-temperature molten salt unit includes a first molten salt conveying pipe and a molten salt heating device arranged in the first molten salt conveying pipe and realizing low-temperature molten salt heating, and molten salt control valves are arranged in the front and rear pipelines of the molten salt heating device.

[0016] According to an embodiment of a molten salt single-tank heat storage system with a high-position molten salt tank of the present invention, the molten salt heat release and transportation component in the high-temperature molten salt unit includes a second molten salt transportation pipeline and a molten salt heat release device arranged in the second molten salt transportation pipeline and realizing high-temperature molten salt heat release, and molten salt control valves are arranged in the front and rear pipelines of the molten salt heat release device.

[0017] According to an embodiment of a molten salt single-tank heat storage system with a molten salt tank arranged at a high position of the present invention, a high-temperature molten salt diverter connected to a molten salt heating and conveying component in a low-temperature molten salt unit is provided in the molten salt storage tank, and a low-temperature molten salt diverter connected to a molten salt heating and conveying component in a high-temperature molten salt unit is also provided in the molten salt storage tank, and the molten salt single-tank heat storage system also includes an electric heating device.

[0018] According to an embodiment of the molten salt single-tank heat storage system with a high-positioned molten salt tank of the present invention, the molten salt storage tank is a packed bed molten salt storage tank filled with a solid particle medium or a pure molten salt storage tank without solid particle filling, the heating heat source of the molten salt heating and conveying component in the low-temperature molten salt unit is at least one of electric energy, solar energy and steam energy, and the heat release object of the molten salt heat release and conveying component in the high-temperature molten salt unit is at least one of a low-temperature medium, a heat-using equipment and a heat user.

[0019] Compared with conventional solutions, the molten salt single tank heat storage system with high-position molten salt tank of the present invention has the following advantages:

[0020] 1) Add a small molten salt tank, adopt a high-position layout of the molten salt tank, and install the low-temperature molten salt pump on the top of the molten salt tank, eliminating the limitation of the submerged shaft length of the molten salt pump on the height of the storage tank, which can further increase the height of the single molten salt heat storage tank, effectively improve the performance of the heat storage system, improve the operating stability of the low-temperature molten salt pump, and further reduce the cost of the molten salt pump and the system;

[0021] 2) The installation of the molten salt tank and the molten salt storage tank uses the "U"-shaped pipe principle to arrange the molten salt tank at a high position so that both it and the molten salt storage tank work under normal pressure, avoiding the sealing problem of the low-temperature molten salt pump and reducing the requirements for auxiliary equipment such as valves and instruments, ensuring the safety and convenience of system operation and maintenance, and reducing the system cost;

[0022] 3) The high-temperature molten salt is at the top of the single tank and the liquid level fluctuation is minimal. The high-temperature molten salt pump is arranged at the top of the storage tank, which effectively reduces the underwater shaft length of the high-temperature molten salt pump, improves the operation stability of the high-temperature molten salt pump, and further reduces the cost of the molten salt pump and the system;

[0023] 4) Compared with the double-tank molten salt heat storage system, this system has low equipment requirements, a simple system, a smaller footprint, a shorter construction period and a lower system cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic structural diagram of a molten salt single-tank heat storage system with a high-position molten salt tank according to an exemplary embodiment of the present invention is shown.

[0025] Description of reference numerals:

[0026] 1-molten salt storage tank, 2-storage tank foundation, 3-molten salt tank, 4-low-temperature molten salt pump, 5-high-temperature molten salt pump, 6-salt discharge tank, 7-salt discharge pump, 8-molten salt heating equipment, 9-molten salt heat release equipment, 10-connecting pipe, 11, 12, 13, 14, 15, 16, 17, 18-molten salt control valve, 19-high-temperature molten salt diverter, 20-low-temperature molten salt diverter. DETAILED DESCRIPTION

[0027] All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and / or steps, can be combined in any manner.

[0028] Any feature disclosed in this specification, unless otherwise stated, can be replaced by other equivalent or alternative features with similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0029] The molten salt single tank heat storage system with a high-position molten salt tank of the present invention is first described in detail below.

[0030] The present invention installs the molten salt tank at a high position beside the molten salt storage tank through a steel structure and other supports, and the installation height of the molten salt tank is at the same horizontal position as the top of the molten salt storage tank and is connected to the atmosphere. The bottom of the molten salt tank is connected to the bottom of the molten salt storage tank by a connecting pipe, so that the liquid level in the molten salt tank is basically consistent with the liquid level in the molten salt storage tank. By using the arrangement method of this "U" type pipe principle, the molten salt tank and the molten salt storage tank can be operated at normal pressure, avoiding the problems caused by the system pressure operation when the molten salt tank is arranged on the ground. In addition, the high-temperature molten salt pump is installed on the top of the molten salt storage tank, and the low-temperature molten salt pump is installed on the top of the molten salt tank instead of the top of the storage tank, eliminating the limitation of the submerged shaft length of the molten salt pump on the height of the storage tank. In addition, because the molten salt tank is small in size, low in height, and operates at normal pressure, the submerged shaft length of the molten salt pump can be effectively reduced, the sealing problem of the pump can be avoided, and the requirements of ancillary equipment such as valves and instruments can be reduced, thereby improving the operating stability of the molten salt pump and reducing the cost of the molten salt pump and the system.

[0031] Figure 1A schematic structural diagram of a molten salt single-tank heat storage system with a high-position molten salt tank according to an exemplary embodiment of the present invention is shown.

[0032] like Figure 1 As shown, according to an exemplary embodiment of the present invention, the molten salt single tank heat storage system with a high-position molten salt tank includes a molten salt storage tank 1, a molten salt tank 3, a low-temperature molten salt unit and a high-temperature molten salt unit.

[0033] Specifically, the molten salt storage tank 1 in the present invention is a single tank arrangement, and the molten salt in the molten salt storage tank 1 is distributed as a high-temperature molten salt layer at the top, a thermoclinic layer in the middle, and a low-temperature molten salt layer at the bottom. The molten salt storage tank 1 is vertically arranged on the storage tank foundation 2, and its height can be specifically set according to actual conditions. Among them, the molten salt storage tank can be a packed bed molten salt storage tank filled with solid particle media or a pure molten salt storage tank without solid particle filling.

[0034] The molten salt tank 3 is arranged at a high position beside the molten salt storage tank 1 and is connected to the atmosphere, and its bottom is connected to the bottom of the molten salt storage tank 1. The molten salt tank 3 can be installed at a high position next to the top of the molten salt storage tank by steel structure support, etc., to store part of the molten salt and buffer the transition and carry the low-temperature molten salt pump. The molten salt tank 3 provided in the present invention is relatively small in volume, preferably arranged horizontally, and a vent connected to the atmosphere is provided on the top. The bottom of the molten salt tank 3 is connected to the bottom of the molten salt storage tank 1 through a connecting pipe 10, and a molten salt control valve 15 and an emptying port are provided in the connecting pipe 10. In addition, it is preferred to control the installation height of the molten salt tank 3 to be at the same horizontal position as the top height of the molten salt storage tank 1, so that the liquid level in the molten salt tank 3 is basically consistent with the liquid level in the molten salt storage tank 1, so that the molten salt tank 3 and the molten salt storage tank 1 are both operated at normal pressure, avoiding the problems caused by the system pressure operation when the molten salt tank 3 is arranged on the ground.

[0035] The low-temperature molten salt unit of the present invention includes a low-temperature molten salt pump 4 installed on the top of the molten salt tank 3 and a molten salt heating and conveying assembly arranged between the low-temperature molten salt pump 4 and the molten salt storage tank 1. The molten salt heating and conveying assembly is used to realize the heating of the low-temperature molten salt and the conveying of the high-temperature molten salt after heating. Specifically, the molten salt heating and conveying assembly in the low-temperature molten salt unit includes a first molten salt conveying pipe and a molten salt heating device 8 arranged in the first molten salt conveying pipe and realizing the heating of the low-temperature molten salt. Molten salt control valves 11 and 12 are arranged in the front and rear pipelines of the molten salt heating device 8. The heating heat source of the low-temperature molten salt in the molten salt heating device 8 is at least one of electric energy, solar energy and steam energy. The molten salt is heated by heat exchange between the heat source and the low-temperature molten salt and is conveyed to the high-temperature molten salt layer on the upper part of the molten salt storage tank 1 after obtaining the high-temperature molten salt. Among them, when the low-temperature molten salt pump and the high-temperature molten salt pump are working, their pump shafts are arranged to be inserted into the molten salt to realize the corresponding molten salt pumping.

[0036] The high-temperature molten salt unit includes a high-temperature molten salt pump 5 installed on the top of the molten salt storage tank 1 and a molten salt heat release and transportation component arranged between the top of the molten salt storage tank 1 and the bottom of the molten salt storage tank 1. The molten salt heat release and transportation component in the high-temperature molten salt unit includes a second molten salt transportation pipeline and a molten salt heat release device 9 arranged in the second molten salt transportation pipeline and realizing high-temperature molten salt heat release. Molten salt control valves 13 and 14 are arranged in the front and rear pipelines of the molten salt heat release device 9. The heat release object of the high-temperature molten salt in the molten salt heat release device 9 is at least one of the low-temperature medium, the heat-using equipment and the heat user. The heat release of the molten salt is realized by heat exchange between the high-temperature molten salt and the heat medium, and the heat is transported to the heat-using equipment, the heat user, etc.

[0037] In addition, the molten salt single-tank heat storage system of the present invention also includes a salt discharge unit, which includes a salt discharge tank 6 and a salt discharge pump 7 arranged on the salt discharge tank 6. The salt discharge pump 7 is connected to the molten salt storage tank 1 through a return pipe to return the molten salt in the salt discharge tank 6 to the molten salt storage tank 1. The salt discharge tank 6 is connected to the connecting pipe and the molten salt heat release and transportation component in the high-temperature molten salt unit (such as connected to the second molten salt transportation pipe) through the salt discharge pipe, and molten salt control valves 16, 17, and 18 are provided in the return pipe and the salt discharge pipe.

[0038] Preferably, a high-temperature molten salt diverter 19 connected to the molten salt heating and conveying component in the low-temperature molten salt unit is provided in the molten salt storage tank 1 to achieve slow diversion of the high-temperature molten salt. The high-temperature molten salt diverter 19 is preferably arranged at the upper high-temperature molten salt layer in the molten salt storage tank 1; the molten salt storage tank 1 is also provided with a low-temperature molten salt diverter 20 connected to the molten salt heating and conveying component in the high-temperature molten salt unit to achieve slow diversion of the low-temperature molten salt. The low-temperature molten salt diverter 20 is preferably arranged at the lower low-temperature molten salt layer in the molten salt storage tank 1.

[0039] In addition, the molten salt single tank heat storage system of the present invention also includes an electric heating device to maintain a suitable temperature of the molten salt in the system to prevent it from solidifying.

[0040] When the system is running, the molten salt fills the molten salt storage tank 1, the lower space of the molten salt tank 3 flush with the liquid level of the molten salt storage tank 1, and the connecting pipe 10 between the molten salt storage tank 1 and the molten salt tank 3. When charging, the low-temperature molten salt pump 4 runs to transport the low-temperature molten salt in the molten salt storage tank 1 from the bottom of the molten salt storage tank 1 through the connecting pipe 10 and the molten salt tank 3 to the molten salt heating device 8. After the low-temperature molten salt absorbs the heat of the high-temperature heat source, it slowly enters the tank from the top of the molten salt storage tank 1 through the first molten salt conveying pipe. When releasing heat, the high-temperature molten salt pump 5 runs to transport the high-temperature molten salt in the molten salt storage tank 1 from the upper part of the molten salt storage tank 1 through the second molten salt conveying pipe to the molten salt heat release device 9, releasing heat to the low-temperature medium, heat-using equipment, heat users, etc. The low-temperature molten salt after heat release slowly enters the tank from the bottom of the molten salt storage tank 1. When the system is in standby, turn on the electric heating device to maintain a suitable temperature of the molten salt in the system to prevent it from solidifying. When the system is shut down for a long time, the molten salt in the molten salt tank 3, the molten salt heating equipment 8, the molten salt heat release equipment and each pipeline is discharged to the salt discharge tank 6 and the molten salt storage tank 1 through various salt discharge ports and pipelines, and the molten salt in the salt discharge tank 6 can be recovered into the molten salt storage tank 1.

[0041] When high- and low-temperature molten salts coexist in the molten salt storage tank 1 during the charging and discharging process, there is a slight difference in their density from the molten salt in the molten salt tank, which will cause a slight difference in the liquid level of the two; and as the charging and discharging process proceeds, the change in the proportion of high- and low-temperature molten salts in the molten salt storage tank will also cause a slight change in the overall density in the molten salt storage tank, thereby causing a slight fluctuation in the liquid level of the molten salt storage tank and the molten salt tank. However, the above-mentioned differences and fluctuations in the liquid level of the molten salt storage tank and the molten salt tank will not affect the operation of this system. It should be noted that when designing the molten salt tank, the diameter of the molten salt tank must take into account the range of variation of the low liquid level and the highest liquid level, so that it can always ensure that the liquid level in the molten salt tank is greater than the cavitation margin of the low-temperature molten salt pump.

[0042] The present invention will be further described below in conjunction with specific embodiments.

[0043] The structure of this embodiment is shown in Figure 1 , mainly composed of molten salt storage tank 1, molten salt tank 3, low temperature molten salt pump 4, high temperature molten salt pump 5 and corresponding pipelines, valves, supporting structures, etc. The valves shown in the figure are only some valves required for the description of this embodiment, and the valves, instruments and supporting structures necessary for other systems are not shown in the figure.

[0044] The single tank of molten salt heat storage 1 is installed vertically on the ground and the lower part is the tank foundation 2. The molten salt tank 3 is installed at a high position next to the top of the molten salt tank 1 through steel structure support. The molten salt tank 3 is small in size and adopts a bedroom layout. A vent connected to the atmosphere is provided on the top. The bottom of the molten salt tank 3 is connected to the bottom of the tank 1 through a connecting pipe 10, and the connecting pipe 10 is provided with a molten salt control valve 15 and a salt discharge port. The high-temperature molten salt pump 5 is installed on the top of the molten salt tank 1, and the low-temperature molten salt pump 4 is installed on the top of the molten salt tank 3.

[0045] When the system is operating normally, the molten salt control valves 16, 17, and 18 are closed, and the molten salt fills the molten salt storage tank 1, the lower space of the molten salt tank 3 flush with the liquid level of the molten salt storage tank 1, and the connecting pipe 10 between the molten salt storage tank 1 and the molten salt tank 3. When charging, the molten salt control valves 11 and 12 are opened, and the low-temperature molten salt pump 4 is operated to transport the low-temperature molten salt in the molten salt storage tank 1 from the bottom of the storage tank 1 through the connecting pipe 10 and the molten salt tank 3 to the molten salt heating device 8. The molten salt that absorbs energy from the heat source and heats up slowly enters the tank from the top of the molten salt storage tank 1 through the high-temperature molten salt diverter 19. When releasing heat, the molten salt control valves 13 and 14 are opened, and the high-temperature molten salt pump 5 is running, and the high-temperature molten salt in the molten salt storage tank 1 is transported from the upper part of the molten salt storage tank 1 to the molten salt heat release device 9, and the heat is released to the low-temperature heat medium and transported to the heat-using equipment, heat users, etc. The molten salt after heat release and cooling slowly enters the tank from the bottom of the molten salt storage tank 1 through the low-temperature molten salt diverter 20. When the system is on standby, the electric heating device is turned on to maintain the appropriate temperature of the molten salt in the system to prevent it from solidifying. When the system is shut down for a long time, keep the molten salt control valves 11-15 and 17 in a closed state, open the molten salt control valves 16 and 18, and discharge the molten salt in the molten salt tank 3, the molten salt heating device 8 and the molten salt heat release device 9, and each pipeline through the salt discharge ports and pipelines to the salt discharge tank 6 and the molten salt storage tank 1; open the molten salt control valve 17, and the molten salt in the salt discharge tank 6 can be recovered to the molten salt storage tank 1 through the salt discharge pump 7 installed on the top of the salt discharge tank 6. It should be noted that when designing the molten salt tank 3 , the diameter of the molten salt tank 3 should take into account the variation range of the low liquid level and the maximum liquid level, so that it can always ensure that the liquid level in the molten salt tank 3 is greater than the cavitation margin of the low-temperature molten salt pump 4 .

[0046] The present invention is not limited to the above-mentioned specific embodiments, but extends to any new features or any new combination disclosed in this specification, as well as any new method or process steps or any new combination disclosed.

Claims

1. A molten salt single tank heat storage system with a high-position molten salt tank, characterized in that: include: Molten salt storage tanks; The molten salt tank is arranged at a high position beside the molten salt storage tank and is connected to the atmosphere, and its bottom is connected to the bottom of the molten salt storage tank; A low-temperature molten salt unit, comprising a low-temperature molten salt pump installed on the top of the molten salt tank and a molten salt heating and conveying assembly arranged between the low-temperature molten salt pump and the molten salt storage tank; A high-temperature molten salt unit, comprising a high-temperature molten salt pump installed on the top of the molten salt storage tank and a molten salt heat release and conveying assembly arranged between the top of the molten salt storage tank and the bottom of the molten salt storage tank; The molten salt in the molten salt storage tank is distributed as a high-temperature molten salt layer at the top, a thermocline layer in the middle, and a low-temperature molten salt layer at the bottom, and the molten salt storage tank is vertically arranged on a storage tank foundation; The bottom of the molten salt storage tank is connected to the bottom of the molten salt tank through a connecting pipe, and a molten salt control valve is arranged in the connecting pipe; The molten salt single tank heat storage system also includes a salt discharge unit, which includes a salt discharge tank and a salt discharge pump arranged on the salt discharge tank, the salt discharge pump is connected to the molten salt storage tank through a return pipe, the salt discharge tank is respectively connected to the connecting pipe and the molten salt heat release and transportation component in the high-temperature molten salt unit through the salt discharge pipe, and the return pipe and the salt discharge pipe are both provided with a molten salt control valve; The molten salt heating and conveying assembly in the low-temperature molten salt unit comprises a first molten salt conveying pipe and a molten salt heating device arranged in the first molten salt conveying pipe and realizing low-temperature molten salt heating, and molten salt control valves are arranged in the front and rear pipelines of the molten salt heating device; The molten salt heat release and transport component in the high-temperature molten salt unit includes a second molten salt transport pipeline and a molten salt heat release device arranged in the second molten salt transport pipeline and realizing high-temperature molten salt heat release, and molten salt control valves are arranged in the front and rear pipelines of the molten salt heat release device; The molten salt storage tank is provided with a high-temperature molten salt diverter connected to the molten salt heating and conveying component in the low-temperature molten salt unit, and the molten salt storage tank is also provided with a low-temperature molten salt diverter connected to the molten salt heating and conveying component in the high-temperature molten salt unit, and the molten salt single tank heat storage system also includes an electric heating device; The molten salt storage tank is a packed bed molten salt storage tank filled with solid particle medium or a pure molten salt storage tank without solid particle filling. The heating heat source of the molten salt heating and conveying component in the low-temperature molten salt unit is at least one of electric energy, solar energy and steam energy. The heat release object of the molten salt heat release and conveying component in the high-temperature molten salt unit is at least one of low-temperature medium, heat-using equipment and heat users.

2. According to claim 1, the molten salt single tank heat storage system with a high-position molten salt tank is characterized in that: The molten salt tank is arranged horizontally and a vent hole connected to the atmosphere is provided on the top. The installation height of the molten salt tank is at the same horizontal position as the top height of the molten salt storage tank, and the liquid level in the molten salt tank is basically consistent with the liquid level in the molten salt storage tank.

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