A molten salt thermal storage system heated by steam

Abstract

The application relates to the field of heat storage and release system technology and discloses a steam heating molten salt heat storage and release system which comprises a low-temperature molten salt tank for containing a low-temperature molten salt medium, a high-temperature molten salt tank for containing a high-temperature molten salt medium, a tubular heat exchanger arranged between the low-temperature molten salt tank and the high-temperature molten salt tank, a first pumping mechanism arranged between the low-temperature molten salt tank and the tube side of the tubular heat exchanger, a second pumping mechanism arranged between the high-temperature molten salt tank and the tube side of the tubular heat exchanger, a steam pipe for steam inlet connected to the tubular heat exchanger, a drainage mechanism for condensed water outlet arranged on the tubular heat exchanger, condensed water capable of flowing back to the tubular heat exchanger under the action of the drainage mechanism when heat is released, and an exhaust pipe for steam outflow connected to the tubular heat exchanger. The application has the effect of improving energy utilization rate.

Description

Technical Field

[0001] This application relates to the field of thermal storage and release system technology, and in particular to a steam-heated molten salt thermal storage and release system. Background Technology

[0002] In my country, with the increase in the installed capacity of new energy sources such as wind power and photovoltaic power, the power generation load of traditional thermal power units has to give way to the power generation load of new energy sources. This requires deep peak-shaving operation of traditional thermal power units. When the generator units are already operating at the minimum load, they still cannot meet the peak-shaving requirements, so energy storage methods are needed. Molten salt thermal energy storage is one of the common methods.

[0003] The generator set uses molten salt thermal storage to store the main steam energy in the form of heat in molten salt. At the appropriate time, the stored heat is used to generate high-quality steam, which is then converted into electrical energy by the steam turbine generator set, thereby improving the peak-shaving capacity of the generator set.

[0004] By directly storing heat using the main steam before the high-pressure cylinder, the heat is stored in the thermal storage system through a single heat exchange. The overall efficiency is relatively high compared to electric energy storage. The system is also relatively simpler than electric energy storage. However, the existing system has more complex piping, a larger heat dissipation area, and lower energy utilization. Summary of the Invention

[0005] To alleviate the problem of complex piping in existing molten salt thermal storage systems, which affects energy utilization, this application provides a steam-heated molten salt thermal storage and release system.

[0006] This application provides a steam-heated molten salt heat storage and release system, which adopts the following technical solution: A steam-heated molten salt heat storage and release system, comprising: Low-temperature molten salt tank, used to hold low-temperature molten salt media; High-temperature molten salt tank, used to hold high-temperature molten salt media; A tubular heat exchanger is disposed between the low-temperature molten salt tank and the high-temperature molten salt tank. A first pumping mechanism is provided between the low-temperature molten salt tank and the tube side of the tubular heat exchanger, and a second pumping mechanism is provided between the high-temperature molten salt tank and the tube side of the tubular heat exchanger. The tubular heat exchanger is connected to a steam pipe for steam to enter, and is equipped with a drainage mechanism for condensate to be discharged. When heat is released, the condensate can flow back into the tubular heat exchanger under the action of the drainage mechanism. The tubular heat exchanger is also connected to an exhaust pipe for steam to flow out.

[0007] By adopting the above technical solution, this system can realize two processes: heat storage and heat release. During heat storage, the first pumping mechanism supplies the low-temperature molten salt medium in the low-temperature molten salt tank to the tube side of the tubular heat exchanger. At the same time, industrial steam enters the tubular heat exchanger from the steam pipe. The steam will exchange heat with the low-temperature molten salt medium in the tubular heat exchanger, and the low-temperature molten salt medium will be heated. At the same time, the steam will condense into liquid water. Then, the low-temperature molten salt medium is heated into a high-temperature molten salt medium and flows to the high-temperature molten salt tank for storage through the second pumping mechanism, thus realizing the heat storage process. During heat release, the second pumping mechanism supplies the high-temperature molten salt medium from the high-temperature molten salt tank to the tubular heat exchanger. At the same time, the condensate in the drainage mechanism is pumped back into the tubular heat exchanger. The condensate will exchange heat with the high-temperature molten salt medium in the tubular heat exchanger. The condensate will be reheated into steam and discharged from the exhaust pipe. Then, after the high-temperature molten salt medium releases heat, it forms a low-temperature molten salt medium that flows back into the low-temperature molten salt tank for storage, thus realizing the heat release process. Heat storage and release can be carried out according to the actual situation. At the same time, heat storage and release are integrated into a unified system, which can effectively reduce the complexity of pipelines, thereby reducing the heat dissipation area and improving energy utilization.

[0008] Preferably, the drainage mechanism includes a water storage tank and a water outlet pipe. The water outlet pipe is connected to the bottom of the tubular heat exchanger, and the end of the water outlet pipe away from the tubular heat exchanger is connected to the water storage tank. A third control valve is provided on the water outlet pipe.

[0009] By adopting the above technical solution and utilizing the water storage tank, when heat storage is performed, the third control valve is opened, and the condensate in the tubular heat exchanger can flow into the water storage tank under the action of gravity, thus ensuring that the condensate in the tubular heat exchanger is discharged in a timely manner and collecting the condensate.

[0010] Preferably, the water storage tank is connected to a return pipe, and the end of the return pipe away from the water storage tank is connected to the top of the tubular heat exchanger. A water pump is installed on the return pipe, and the water pump is used to pump the distilled water in the water storage tank back to the tubular heat exchanger.

[0011] By adopting the above technical solution, when releasing heat, the water pump is started, and the second water pump is used to pump the condensate in the water storage tank. Then, the condensate exchanges heat with the high-temperature molten salt medium entering the tubular heat exchanger, so as to realize the reuse of condensate. Only one water storage tank is needed to realize the recycling of condensate.

[0012] Preferably, a medium-temperature molten salt tank is provided between the low-temperature molten salt tank and the high-temperature molten salt tank. The medium-temperature molten salt tank contains a medium-temperature molten salt medium. A heat exchange box is fixedly connected to the side wall of the medium-temperature molten salt tank. The medium-temperature molten salt tank is provided with a circulation supply mechanism for circulating the medium-temperature molten salt medium to the heat exchange box. The return pipe passes through the heat exchange box and communicates with the tubular heat exchanger.

[0013] By adopting the above technical solution, when the demand for steam is large, the circulating supply mechanism on the medium-temperature molten salt tank circulates medium-temperature molten salt medium into the heat exchange box. The medium-temperature molten salt medium in the heat exchange box heats the condensate in the return pipe and then enters the tubular heat exchanger. Since the condensate has been heated to a certain temperature under the action of the medium-temperature molten salt medium, it can be rapidly vaporized in the tubular heat exchanger, thereby improving the steam conversion efficiency.

[0014] Preferably, the circulating supply mechanism includes a third molten salt pump and two supply pipes, which are respectively connected to opposite ends of the heat exchange box. One end of the supply pipe away from the heat exchange box is connected to the top of the medium-temperature molten salt tank, and the other end of the supply pipe away from the heat exchange box is connected to the bottom of the medium-temperature molten salt tank. The third molten salt pump is mounted on one of the supply pipes.

[0015] By adopting the above technical solution, the outlet and inlet of the medium-temperature molten salt tank are located at opposite ends of the medium-temperature molten salt tank, thereby reducing the possibility of medium-temperature molten salt medium being extracted during circulation and ensuring the heat exchange efficiency with the medium in the return pipe.

[0016] Preferably, a branch pipe is connected to the steam pipe, and the end of the branch pipe away from the steam pipe is connected to the return pipe. The connection between the branch pipe and the steam pipe is located near the water storage tank, and a fourth control valve is provided on the branch pipe.

[0017] By adopting the above technical solution, during heat storage, the fourth control valve is opened, and part of the steam introduced into the steam pipe will enter the distribution pipe, and then enter the tubular heat exchanger through the return pipe. When the steam passes through the heat exchange box, it will exchange heat with the medium-temperature heat exchange medium in the heat exchange box, thereby replenishing the energy of the medium-temperature heat exchange medium.

[0018] Preferably, a water inlet pipe is connected to the return pipe, and the connection between the water inlet pipe and the return pipe is located on the side of the water pump away from the water storage tank. The water inlet pipe is connected to the water storage tank, and a fifth control valve is provided on the water inlet pipe.

[0019] By adopting the above technical solution, opening the fifth control valve allows the condensate generated by the condensation of steam in the return pipe to flow back into the water storage tank, so that the liquid in the return pipe can be discharged in time, avoiding any impact on the steam supply.

[0020] Preferably, a blocking fan blade is rotatably connected inside the return pipe, the blocking fan blade facing the direction of steam flow, and the blocking fan blade is used to block the condensed steam in the return pipe.

[0021] By adopting the above technical solution, when steam flows in the return tube, the steam will blow the fan blades in the return tube to stop the rotation, thereby blocking some of the liquefied water mixed in the steam, reducing the amount of liquefied water entering the tubular heat exchanger, and ensuring the heat exchange efficiency of the tubular heat exchanger.

[0022] Preferably, a rotating assembly is provided on the return pipe. The rotating assembly includes a drive motor and a rotating ring. The drive motor is fixedly connected to the return pipe, and the rotating ring is rotatably connected inside the return pipe. The drive motor is driven by the rotating ring to drive the rotating ring to rotate. The blocking fan blade is rotatably connected to the rotating ring.

[0023] By adopting the above technical solution, the rotating setting of the flip ring is used to drive the flip ring to rotate when pumping coolant into the tubular heat exchanger, thereby driving the blocking fan blade to rotate. This makes the direction of the blocking fan blade the same as the pumping direction of the water flow, thus avoiding the blocking fan blade from obstructing the pumping of the water flow. When steam needs to be transported, the flip ring is driven to drive the blocking fan blade back to its original position.

[0024] In summary, this application includes at least the following beneficial technical effects: By installing a tubular heat exchanger between the low-temperature molten salt tank and the high-temperature molten salt tank, and using a water storage tank to collect the condensate, heat storage and release can be carried out according to actual needs. At the same time, the heat storage and release are integrated into a single system, which can effectively reduce the complexity of the piping, thereby reducing the heat dissipation area and improving energy utilization. By setting up a medium-temperature molten salt tank between the low-temperature molten salt tank and the high-temperature molten salt tank, when the demand for steam is large, the circulation supply mechanism on the medium-temperature molten salt tank circulates medium-temperature molten salt medium into the heat exchange box. The medium-temperature molten salt medium in the heat exchange box heats the condensate in the return pipe and then enters the tubular heat exchanger. Since the condensate has been heated to a certain temperature under the action of the medium-temperature molten salt medium, it can be rapidly vaporized in the tubular heat exchanger, thereby improving the steam conversion efficiency. By installing obstructing blades inside the return pipe, when steam flows in the return pipe, the steam will blow the obstructing blades inside the return pipe to rotate, thereby blocking some of the liquefied water mixed in with the steam, reducing the amount of liquefied water entering the tubular heat exchanger, and ensuring the heat exchange efficiency of the tubular heat exchanger. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application; Figure 2 This is a schematic diagram of the structure of the first pumping mechanism in the embodiments of this application; Figure 3 This is a schematic diagram of the drainage mechanism in an embodiment of this application; Figure 4 This is a schematic diagram of the structure of the circulating supply mechanism in the embodiments of this application; Figure 5 This is a schematic diagram of the structure of the blocking fan blade in an embodiment of this application.

[0026] Reference numerals: 100, Low-temperature molten salt tank; 110, First pumping mechanism; 111, First connecting pipe; 112, First flow pipe; 113, First control valve; 114, First molten salt pump; 200, High-temperature molten salt tank; 210, Second pumping mechanism; 211, Second connecting pipe; 212, Second flow pipe; 213, Second control valve; 214, Second molten salt pump; 300, Tubular heat exchanger; 310, Steam pipe; 320, Exhaust pipe; 400, Drainage mechanism; 410, Water storage tank; 420. Outlet pipe; 430. Third control valve; 440. Return pipe; 450. Water pump; 500. Medium-temperature molten salt tank; 510. Heat exchange box; 520. Circulation supply mechanism; 521. Supply pipe; 522. Third molten salt pump; 600. Diverter pipe; 610. Fourth control valve; 620. Water inlet pipe; 630. Fifth control valve; 700. Rotating assembly; 710. Drive motor; 720. Tilting ring; 800. Blocking fan blade; 900. Liquid passage pipe; 910. Fourth molten salt pump. Detailed Implementation

[0027] The following is in conjunction with the appendix Figure 1-5 This application will be described in further detail.

[0028] This application discloses a steam-heated molten salt storage and release system.

[0029] Reference Figure 1 and Figure 2A steam-heated molten salt storage and release system includes a low-temperature molten salt tank 100, a high-temperature molten salt tank 200, and a tubular heat exchanger 300. The low-temperature molten salt tank 100 is used to hold low-temperature molten salt medium, and the high-temperature molten salt tank 200 is used to hold high-temperature molten salt medium. The tubular heat exchanger 300 is located between the low-temperature molten salt tank 100 and the high-temperature molten salt tank 200. A first pumping mechanism 110 is provided between the low-temperature molten salt tank 100 and the tubular heat exchanger 300 to connect them. A second pumping mechanism 210 is provided between the high-temperature molten salt tank 200 and the tubular heat exchanger 300 to connect them.

[0030] Reference Figure 1 and Figure 2 The first pumping mechanism 110 includes a first connecting pipe 111. One end of the first connecting pipe 111 is connected to the tube side inside the tubular heat exchanger 300. The other end of the first connecting pipe 111 is connected to two second flow pipes 212. The ends of the two first flow pipes 112 away from the first connecting pipe 111 extend into the low-temperature molten salt tank 100 and are connected to the low-temperature molten salt tank 100. One of the first flow pipes 112 is equipped with a first control valve 113, and the other first flow pipe 112 is equipped with a first molten salt pump 114. The second pumping mechanism 210 includes a second connecting pipe 211. One end of the second connecting pipe 211 is connected to the tube side inside the tubular heat exchanger 300. The other end of the second connecting pipe 211 is connected to two second flow pipes 212. The ends of the two second flow pipes 212 away from the second connecting pipe 211 extend into the high-temperature molten salt tank 200 and are connected to the high-temperature molten salt tank 200. A second control valve 213 is provided on one of the second flow pipes 212, and a second molten salt pump 214 is provided on the other second flow pipe 212. Reference Figure 1 and Figure 2 A steam pipe 310 is connected to the tubular heat exchanger 300, allowing industrial steam to enter the tubular heat exchanger 300 through the steam pipe 310. A drainage mechanism 400 is installed at the bottom of the tubular heat exchanger 300, allowing condensate from the steam condensation to flow from the tubular heat exchanger 300 into the drainage mechanism 400. An exhaust pipe 320 is connected to the tubular heat exchanger 300, and an on / off valve is installed on the exhaust pipe 320 to control its opening and closing. Steam generated during the heat release process can be discharged from the tubular heat exchanger 300 through the exhaust pipe 320.

[0031] Reference Figure 1 and Figure 3The drainage mechanism 400 includes a water storage tank 410, which is located at the bottom of the tubular heat exchanger 300. A water outlet pipe 420 is provided between the water storage tank and the tubular heat exchanger 300. The tubular heat exchanger 300 is connected to the water storage tank 410 through the water outlet pipe 420. A third control valve 430 is installed on the water outlet pipe 420. The third control valve 430 is used to control the opening and closing of the water outlet pipe 420. A return pipe 440 is connected to the water storage tank 410. The end of the return pipe 440 away from the water storage tank 410 passes through the top of the tubular heat exchanger 300 and communicates with the inside of the tubular heat exchanger 300. A water pump 450 is installed on the return pipe 440. The water pump 450 is used to pump the condensate in the water storage tank 410 to the tubular heat exchanger 300.

[0032] This system can realize two processes: heat storage and heat release. During heat storage, the first control valve 113 and the second molten salt pump 214 are closed, the on / off valve is closed, and then the first molten salt pump 114 is started. The first molten salt pump 114 is used to pump the low-temperature molten salt medium in the low-temperature molten salt tank 100 to the tube side of the tubular heat exchanger 300. At the same time, industrial steam enters the tubular heat exchanger 300 through the steam pipe 310. The steam will exchange heat with the low-temperature molten salt medium in the tubular heat exchanger 300. The low-temperature molten salt medium is heated, and the steam will condense into liquid water and flow from the water outlet pipe 420 into the water storage tank 410 for storage. Then, the low-temperature molten salt medium is heated into a high-temperature molten salt medium and flows through the second pumping mechanism 210 to the high-temperature molten salt tank 200 for storage, thus realizing the heat storage process. During heat release, the first molten salt pump 114 and the second control valve 213 are closed, the third control valve 430 is closed, the on / off valve is opened, and then the second molten salt pump 214 is started. The second molten salt pump 214 pumps the high-temperature molten salt medium in the high-temperature molten salt tank 200 to the tubular heat exchanger 300. At the same time, the water pump 450 is started to pump the condensate in the water storage tank 410 back to the tubular heat exchanger 300 through the return pipe 440. Then, the condensate will exchange heat with the high-temperature molten salt medium in the tubular heat exchanger 300. The condensate will be reheated into steam and discharged from the exhaust pipe 320. After the high-temperature molten salt medium releases heat, it forms a low-temperature molten salt medium that flows back to the low-temperature molten salt tank 100 for storage, thus realizing the heat release process. In this embodiment, heat storage and heat release are simultaneously implemented as a unified system, which can effectively reduce the complexity of the pipeline, thereby reducing the heat dissipation area and improving energy utilization.

[0033] Reference Figure 1 , Figure 3 and Figure 4Below the tubular heat exchanger 300 is a medium-temperature molten salt tank 500, which is used to hold medium-temperature molten salt medium. The medium-temperature molten salt tank 500 is located between the low-temperature molten salt tank 100 and the high-temperature molten salt tank 200. A heat exchange box 510 is fixedly connected to one side of the medium-temperature molten salt tank 500. The return pipe 440 passes through the heat exchange box 510 and then communicates with the tubular heat exchanger 300. The return pipe 440 is spirally arranged inside the heat exchange box 510.

[0034] A circulation supply mechanism 520 is installed between the medium-temperature molten salt tank 500 and the heat exchange box 510. The circulation supply mechanism 520 includes a supply pipe 521 that passes through the bottom of the medium-temperature molten salt tank 500 and communicates with the inside of the medium-temperature molten salt tank 500. One end of the supply pipe 521 away from the medium-temperature molten salt tank 500 passes through the bottom of the heat exchange box 510 and communicates with the inside of the heat exchange box 510. A third molten salt pump 522 is installed on the supply pipe 521. Another supply pipe 521 passes through the top of the heat exchange box 510 and one end of the other supply pipe 521 that is away from the heat exchange box 510 passes through the top of the medium-temperature molten salt tank 500. When the water pump 450 is started to pump the condensate in the water storage tank 410 to the tubular heat exchanger 300, the condensate will pass through the heat exchange box 510. At the same time, the third molten salt pump 522 is started to supply medium-temperature molten salt medium into the heat exchange box 510. The medium-temperature molten salt medium then pre-heats the condensate in the heat exchange box 510 before it enters the tubular heat exchanger 300. Since the condensate has been heated to a certain temperature under the action of the medium-temperature molten salt medium, it can be quickly vaporized in the tubular heat exchanger 300, thereby improving the steam conversion efficiency.

[0035] Reference Figure 1 and Figure 4A branch pipe 600 is connected to the steam pipe 310. The end of the branch pipe 600 away from the steam pipe 310 is connected to the return pipe 440. The connection between the branch pipe 600 and the return pipe 440 is located between the water pump 450 and the heat exchange box 510. A fourth control valve 610 is installed on the branch pipe 600 to control the opening and closing of the branch pipe 600. A water inlet pipe 620 is connected to the return pipe 440. The connection between the water inlet pipe 620 and the return pipe 440 is located below the connection between the branch pipe 600 and the return pipe 440, and above the water pump 450. The end of the water inlet pipe 620 away from the return pipe 440 is connected to the inside of the water storage tank 410. A fifth control valve 630 is installed on the water inlet pipe 620. During heat storage, the fourth control valve 610 is opened. Steam enters the tubular heat exchanger 300 through the steam pipe 310 and also enters the branch pipe 600. Then, it enters the tubular heat exchanger 300 through the return pipe 440. When the steam passes through the return pipe 440, it will exchange heat with the medium-temperature heat exchange medium in the heat exchange box 510, thereby replenishing the medium-temperature heat exchange medium with energy.

[0036] Reference Figure 4 and Figure 5 A rotating assembly 700 is installed on the return pipe 440. The rotating assembly 700 includes a drive motor 710 fixedly connected to one side of the return pipe 440. The axis of the main shaft of the drive motor 710 is perpendicular to the length direction of the return pipe 440. A flip ring 720 is rotatably connected inside the return pipe 440. The main shaft of the drive motor 710 is fixedly connected to the flip ring 720 to drive the flip ring 720 to rotate. A blocking fan blade 800 is rotatably connected inside the flip ring 720. During heat release, the obstruction fan blade 800 faces the same direction as the flow of condensate in the return pipe 440, reducing obstruction to the condensate. During heat storage, the drive motor 710 is started, which drives the rotating ring 720 to rotate, causing the obstruction fan blade 800 to rotate 180 degrees. As the steam flows back into the return pipe, the steam blows the obstruction fan blade 800 in the return pipe 440 to rotate, thus blocking some of the liquefied water mixed in with the steam. This reduces the amount of liquefied water entering the tubular heat exchanger 300, ensuring the heat exchange efficiency of the tubular heat exchanger 300.

[0037] Reference Figure 1 and Figure 4A liquid flow pipe 900 connects the intermediate-temperature molten salt tank 500 and the high-temperature molten salt tank 200. A fourth molten salt pump 910 is installed on the liquid flow pipe 900. The fourth molten salt pump 910 is used to pump the high-temperature molten salt medium in the high-temperature molten salt pump to the intermediate-temperature molten salt tank 500, and can also pump the intermediate-temperature molten salt medium in the intermediate-temperature molten salt tank 500 back to the high-temperature molten salt tank 200. When the temperature of the intermediate-temperature molten salt medium in the intermediate-temperature molten salt tank 500 is too low, the fourth molten salt pump 910 is started, and then part of the high-temperature molten salt medium in the high-temperature molten salt pump is pumped to the intermediate-temperature molten salt tank 500, thereby regulating the intermediate-temperature molten salt medium in the intermediate-temperature molten salt tank 500. At the same time, the fourth molten salt pump 910 can also pump the intermediate-temperature molten salt medium in the intermediate-temperature molten salt tank 500 to the high-temperature molten salt tank 200, facilitating the regulation of the intermediate-temperature molten salt medium in the intermediate-temperature molten salt tank 500.

[0038] The implementation principle of the steam-heated molten salt heat storage and release system in this application embodiment is as follows: This system can realize two processes of heat storage and heat release. During heat storage, after steam enters the tubular heat exchanger 300 from the steam pipe 310, the first molten salt pump 114 simultaneously pumps the low-temperature molten salt medium into the tube side of the tubular heat exchanger 300. Then, the steam will exchange heat with the low-temperature molten salt medium in the tubular heat exchanger 300, and the low-temperature molten salt medium will be heated. At the same time, the steam will condense into liquid water. Then, the low-temperature molten salt medium will be heated into a high-temperature molten salt medium and flow to the high-temperature molten salt tank 200 for storage through the second pumping mechanism 210, thus realizing the heat storage process. During heat release, water pump 450 is started to pump condensate from storage tank 410 to tubular heat exchanger 300. At the same time, second molten salt pump 214 is started to pump high-temperature molten salt medium from high-temperature molten salt tank 200 to the tube side of tubular heat exchanger 300. The condensate will exchange heat with the high-temperature molten salt medium in tubular heat exchanger 300. The condensate will be reheated into steam and discharged from exhaust pipe 320. Then, after the high-temperature molten salt medium releases heat, it forms low-temperature molten salt medium which flows back to low-temperature molten salt tank 100 for storage, thus realizing the heat release process. This application adopts a unified system for heat storage and heat release, which can effectively reduce the complexity of pipelines, thereby reducing the heat dissipation area and improving energy utilization.

[0039] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A steam-heated molten salt heat storage and release system, characterized in that: include Low-temperature molten salt vessel (100) is used to hold low-temperature molten salt medium; High-temperature molten salt tank (200) is used to hold high-temperature molten salt media; A tubular heat exchanger (300) is disposed between the low-temperature molten salt tank (100) and the high-temperature molten salt tank (200). A first pumping mechanism (110) is provided between the low-temperature molten salt tank (100) and the tube side of the tubular heat exchanger (300), and a second pumping mechanism (210) is provided between the high-temperature molten salt tank (200) and the tube side of the tubular heat exchanger (300). The tubular heat exchanger (300) is connected to a steam pipe (310) for steam to enter, and the tubular heat exchanger (300) is provided with a drain mechanism (400) for condensate to be discharged. When heat is released, the condensate can flow back into the tubular heat exchanger (300) under the action of the drain mechanism (400). The tubular heat exchanger (300) is connected to an exhaust pipe (320) for steam to flow out. The drainage mechanism (400) includes a water storage tank (410) and a water outlet pipe (420). The water outlet pipe (420) is connected to the bottom of the tubular heat exchanger (300), and one end of the water outlet pipe (420) away from the tubular heat exchanger (300) is connected to the water storage tank (410). A return pipe (440) is connected to the water storage tank (410), and the end of the return pipe (440) away from the water storage tank (410) is connected to the top of the tubular heat exchanger (300). A medium-temperature molten salt tank (500) is provided between the low-temperature molten salt tank (100) and the high-temperature molten salt tank (200). The medium-temperature molten salt tank (500) contains a medium-temperature molten salt medium. A heat exchange box (510) is fixedly connected to the side wall of the medium-temperature molten salt tank (500). A circulation supply mechanism (520) for circulating supplying the medium-temperature molten salt medium to the heat exchange box (510) is provided on the medium-temperature molten salt tank (500). The return pipe (440) passes through the heat exchange box (510) and communicates with the tubular heat exchanger (300). A liquid-passing pipe (900) connects the medium-temperature molten salt tank (500) and the high-temperature molten salt tank (200).

2. The steam-heated molten salt heat storage and release system according to claim 1, characterized in that: A third control valve (430) is installed on the water outlet pipe (420).

3. The steam-heated molten salt heat storage and release system according to claim 2, characterized in that: A water pump (450) is installed on the return pipe (440), and the water pump (450) is used to return the distilled water pump (450) in the water storage tank (410) to the tubular heat exchanger (300).

4. The steam-heated molten salt heat storage and release system according to claim 1, characterized in that: The circulating supply mechanism (520) includes a third molten salt pump (522) and two supply pipes (521). The two supply pipes (521) are respectively connected to opposite ends of the heat exchange box (510). One end of one supply pipe (521) away from the heat exchange box (510) is connected to the top of the medium-temperature molten salt tank (500), and the other end of the supply pipe (521) away from the heat exchange box (510) is connected to the bottom of the medium-temperature molten salt tank (500). The third molten salt pump (522) is mounted on one of the supply pipes (521).

5. The steam-heated molten salt heat storage and release system according to claim 3, characterized in that: A branch pipe (600) is connected to the steam pipe (310). The end of the branch pipe (600) away from the steam pipe (310) is connected to the return pipe (440). The connection between the branch pipe (600) and the steam pipe (310) is located near the water storage tank (410). A fourth control valve (610) is provided on the branch pipe (600).

6. The steam-heated molten salt heat storage and release system according to claim 5, characterized in that: The return pipe (440) is connected to a water inlet pipe (620). The connection between the water inlet pipe (620) and the return pipe (440) is located on the side of the water pump (450) away from the water storage tank (410). The water inlet pipe (620) is connected to the water storage tank (410). A fifth control valve (630) is provided on the water inlet pipe (620).

7. The steam-heated molten salt heat storage and release system according to claim 3, characterized in that: A blocking fan blade (800) is rotatably connected inside the return pipe (440). The blocking fan blade (800) faces the direction of steam flow and is used to block the condensed steam in the return pipe (440).

8. The steam-heated molten salt heat storage and release system according to claim 7, characterized in that: A rotating assembly (700) is provided on the return pipe (440). The rotating assembly (700) includes a drive motor (710) and a rotating ring (720). The drive motor (710) is fixedly connected to the return pipe (440), and the rotating ring (720) is rotatably connected inside the return pipe (440). The drive motor (710) is connected to the rotating ring (720) in a transmission connection to drive the rotating ring (720) to rotate. The blocking fan blade (800) is rotatably connected to the rotating ring (720).

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