A molten salt heat storage steam supply system

Abstract

The invention discloses a molten salt heat storage steam supply system, and relates to the technical field of valley power heat storage heating system. The molten salt heat storage steam supply system comprises: a low-temperature molten salt tank; a high-temperature molten salt tank, the high-temperature molten salt tank is used to receive the low-temperature molten salt in the low-temperature molten salt tank and heat the low-temperature molten salt to form high-temperature molten salt; and a secondary molten salt heat exchanger and a primary molten salt heat exchanger, the high-temperature molten salt in the high-temperature molten salt tank passes through the secondary molten salt heat exchanger and the primary molten salt heat exchanger in turn and then returns to the low-temperature molten salt tank, and the water in the water supply module passes through the primary molten salt heat exchanger and the secondary molten salt heat exchanger in turn and exchanges heat with the high-temperature molten salt; the molten salt heat storage steam supply system, by setting an outer shell, a middle shell and a thin tank, makes the water exchanged by the high-temperature molten salt entering the thin tube be the water that has been heat exchanged by the outer shell, and makes the crystal precipitation position change from the original pipe pass to the outer surface of the middle heat exchange shell, which is convenient for cleaning.

Description

Technical Field

[0001] The present invention relates to the technical field of valley electricity heat storage and heating systems, and in particular to a molten salt heat storage and steam supply system. Background Art

[0002] For industries with large steam consumption, coal is the main fuel for the industrial steam industry, mainly coal and natural gas, with a small amount of biomass fuel and solid waste. Changes in the prices of coal and other fuels directly affect the operating conditions of industrial steam companies; the downstream is mainly heating, petrochemical, textile and other industrial users. This type of steam generation scenario is usually accompanied by high emissions, low efficiency and other drawbacks, which is slightly different from the energy-saving and environmental protection, dual carbon and other policies currently implemented in my country. The steam production industry using the above as fuel is also constantly improving its clean production capabilities and industry production efficiency.

[0003] For industries with low steam consumption, natural gas boilers and electric steam generators (boilers) are the main steam generation equipment. However, in these two technical routes, there are gas use risks such as high energy costs and unstable energy supply (natural gas), and there is also the risk of restricting the production and development of steam-using enterprises.

[0004] Steam is the source of industrial power, especially in industrial heating, steam is a better choice. In the industrial field, the use of steam is not subject to seasonal restrictions like hot water for heating, and has a higher utilization rate in terms of time. At present, the proportion of traditional coal-fired boilers used in industry is still relatively large, but with the continuous increase in the country's efforts in ecological environmental protection and pollution control, coupled with the vigorous promotion of "coal to gas" and "coal to electricity", the industrial steam field is slowly being replaced by gas boilers or electric boilers, and the market potential for energy-saving transformation of industrial boilers is huge.

[0005] At present, the technology of electric heat storage steam supply system is mainly in the stage of technical research and development and preliminary application. Its basic principle is to use cheap electricity as the energy source for heating the heat storage material, store the energy in the heat storage material, and when steam is needed, take the heat out of the heat storage material through various heat transfer means, and exchange heat with water to generate steam.

[0006] The molten salt heat storage system has been commercially applied in solar thermal power plants, and can be easily converted into an electric heat storage steam supply system. The molten salt heat storage system uses molten salt as a heat transfer and storage medium. When the electricity price is low, the molten salt is heated by electricity. The temperature of the molten salt rises, and the heat is stored in the molten salt in the form of sensible heat. When steam is needed, the molten salt directly exchanges heat with water to produce steam. The advantage of the system is that it is mature and stable.

[0007] However, the molten salt heat exchange equipment in the prior art mostly adopts a shell and tube heat exchanger, in which the high-temperature molten salt flows through the tube side, and the water to be exchanged flows through the shell side. At the water inlet, due to the low initial water temperature, the temperature of part of the high-temperature molten salt in the tube side (this part of the high-temperature molten salt refers to the molten salt close to the inner wall of the tube side) drops sharply, causing the molten salt to precipitate crystals. Long-term use causes the molten salt inlet of the tube side to be blocked and difficult to clean. Summary of the invention

[0008] In view of the deficiencies of the prior art, the present invention provides a molten salt heat storage and steam supply system, which solves the problem in the prior art that molten salt crystals precipitate, and the molten salt inlet of the pipe is blocked and difficult to clean due to long-term use.

[0009] To achieve the above objectives, the present invention is implemented through the following technical solutions: a molten salt heat storage and steam supply system, comprising: a low-temperature molten salt tank; a high-temperature molten salt tank, the high-temperature molten salt tank is used to receive the low-temperature molten salt in the low-temperature molten salt tank and heat the low-temperature molten salt to form high-temperature molten salt; and a secondary molten salt heat exchanger and a primary molten salt heat exchanger, the high-temperature molten salt in the high-temperature molten salt tank passes through the secondary molten salt heat exchanger and the primary molten salt heat exchanger in turn and then returns to the low-temperature molten salt tank, the water in the water supply module passes through the primary molten salt heat exchanger and the secondary molten salt heat exchanger in turn and exchanges heat with the high-temperature molten salt to form water vapor; wherein the primary molten salt heat exchanger comprises: an outer shell body; a middle heat exchange shell, wherein the middle heat exchange shell is provided with one or more groups, the middle heat exchange shell is arranged in the outer shell, and the shell side in the middle heat exchange shell has water to be heat exchanged flowing from bottom to top; capillaries, wherein the capillaries are distributed in the middle heat exchange shell; the high-temperature molten salt enters the outer shell at the lower part of the outer shell, and exchanges heat with the water to be heat exchanged in the shell side of the middle heat exchange shell through the middle heat exchange shell, and the high-temperature molten salt can enter the capillaries and exchange heat with the water to be heat exchanged in the middle heat exchange shell, and the position where the high-temperature molten salt enters the capillaries is higher than the position where the water to be heat exchanged enters the middle heat exchange shell, so that the water exchanged with the high-temperature molten salt entering the capillaries is the water that has been heat exchanged with the outer shell.

[0010] Furthermore, the middle-layer heat exchange shell includes a middle-layer shell and a convex nozzle barrel, the middle-layer shell is arranged in the outer-layer shell along the axial direction of the outer-layer shell, and the convex nozzle barrel is arranged at the lower part of one side of the middle-layer shell; a bending tube is provided at the lower end of the capillary tube, an angle is formed between the bending tube and the capillary tube, and the bending tube is located in the convex nozzle barrel, a convex nozzle baffle is fixed in the capillary tube, a through hole opposite to the bending tube is formed on the convex nozzle baffle, and the high-temperature molten salt in the outer-layer shell is used to enter the bending tube; a second water inlet interface is fixed on one side of the lower part of the middle-layer shell, the second water inlet interface is used to enter the water to be heat exchanged, and a reserved length is provided between the second water inlet interface and the convex nozzle barrel, and the water to be heat exchanged entering from the second water inlet interface only exchanges heat with the high-temperature molten salt outside the middle-layer shell within the reserved length, and does not exchange heat with the high-temperature molten salt in the capillary tube.

[0011] Furthermore, the upper end of the outer shell extends to the upper end of the middle shell, and the upper end of the outer shell is fixedly provided with an outer top cover, and the upper end of the middle shell passes through the outer top cover; a first partition is fixedly provided at the lower inner part of the outer shell, and the first partition is higher than the height of the convex nozzle tube. The first partition can prevent the high-temperature molten salt in the outer shell from continuously moving upward, so that the high-temperature molten salt in the outer shell will no longer move upward after reaching the height of the convex nozzle tube.

[0012] Furthermore, the upper end of the outer shell extends to above the protruding nozzle, and an outer top cover is fixedly provided on the upper end of the outer shell.

[0013] Furthermore, a high-temperature molten salt feed port is provided at the lower portion of one side of the outer shell, and the high-temperature molten salt enters the outer shell through the high-temperature molten salt feed port; a molten salt discharge port is provided at the upper end of the middle shell, and a plurality of the molten salt discharge ports are connected to molten salt discharge pipe fittings, and the discharge ports of the molten salt discharge pipe fittings are connected to the feed port of the low-temperature molten salt tank; a second top plate is fixedly provided at the upper end of the middle shell, and a through hole is opened on the second top plate at a position opposite to the capillary tube, for the molten salt in the capillary tube to enter the molten salt discharge pipe fitting.

[0014] Furthermore, a water inlet pipe fitting is provided at the lower portion of the middle shell, and the water inlet pipe fitting includes a water inlet main pipe, and the water inlet main pipe is an arc-shaped pipe. A water inlet branch is provided at an area on the water inlet main pipe opposite to the second water inlet interface, and a second water inlet branch pipe is fixedly provided at one end of the water inlet branch close to the outer shell, and a butt pipe connected to the second water inlet branch pipe is provided on the outer shell, and the other end of the butt pipe is fixedly connected to the second water inlet interface; a drainage pipe fitting is provided on the periphery of the upper portion of the middle shell.

[0015] Furthermore, a second partition is provided near the lower end of the middle shell, and the second partition is used to isolate the middle shell into a space with high-temperature molten salt and a space without high-temperature molten salt. The space above the second partition is the space with high-temperature molten salt, and the space below the second partition is the space without high-temperature molten salt.

[0016] Furthermore, the lower end of the outer shell is fixed with an outer bottom cover via a flange; and the lower end of the middle shell is installed on the outer bottom cover via a flange.

[0017] Furthermore, it also includes a debris removal component, which includes: a scraper ring, which is sleeved on the lower periphery of the middle shell, and a notch is provided on the scraper ring in the area opposite to the second water inlet interface; a threaded rod, which is installed in the outer shell along the axial direction of the outer shell, and a nut is threadedly connected to the threaded rod, and a connecting rod is provided between the nut and the scraper ring.

[0018] Furthermore, the water supply module includes: a water treatment device, which is used to treat municipal water; a make-up water tank, which is used to store water treated by the water treatment device; and a water supply pump, which is used to transport water to the primary molten salt heat exchanger.

[0019] The present invention has the following beneficial effects:

[0020] The molten salt heat storage steam supply system is provided with an outer shell, a middle shell and a capillary tank, so that the high-temperature molten salt in the outer shell can first exchange heat with the water in the shell side of the middle shell through the shell wall of the middle shell, and the feeding position of the high-temperature molten salt into the capillary tube is higher than the position of the water to be heat-exchanged into the middle heat exchange shell, so that the water exchanged with the high-temperature molten salt entering the capillary tube is the water that has been heat-exchanged by the outer shell, so that the molten salt entering the capillary tube will not produce crystallization, and the capillary tube is prevented from being blocked when the water exchanges heat with the high-temperature molten salt. In addition, because the high-temperature molten salt first exchanges heat with the water outside the middle heat exchange shell, the crystal precipitation position is changed from the original tube side to the outer surface of the middle heat exchange shell, which is convenient for cleaning.

[0021] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is the overall flow chart of the present invention;

[0023] Figure 2 The secondary molten salt heat exchanger in the first embodiment of the present invention;

[0024] Figure 3 For the present invention Figure 2 Schematic diagram without bracket installed;

[0025] Figure 4 It is a partial cutaway view of the outer shell of the present invention;

[0026] Figure 5 is a cutaway view of the middle shell of the present invention;

[0027] Figure 6 For the present invention Figure 5 A partial map of

[0028] Figure 7 A diagram showing the connection between one of the thin tubes and the middle shell of the present invention;

[0029] Figure 8 is a cutaway view of the outer shell of the present invention;

[0030] Fig. 9 For the present invention Figure 4 A magnified view of area B;

[0031] Fig.10This is a front view of the internal structure of the outer shell in the first embodiment of the present invention;

[0032] Fig.11 This is a flow diagram of water and high-temperature molten salt in a secondary molten salt heat exchanger in Example 1 of the present invention;

[0033] Fig.12 For the present invention Figure 4 A magnified image of area A;

[0034] Fig.13 This is a structural front view of the outer shell in the second embodiment of the present invention;

[0035] Fig.14 This is a flow diagram of water and high-temperature molten salt in a secondary molten salt heat exchanger in Example 2 of the present invention.

[0036] In the figure, 1, high temperature molten salt tank; 2, low temperature molten salt tank; 3, secondary molten salt heat exchanger; 4, primary molten salt heat exchanger; 410, bracket; 420, outer tank shell; 421, outer shell; 4211, butt pipe; 422, outer top cover; 423, drainage pipe fittings; 424, water inlet pipe fittings; 4241, first water inlet interface; 4242, water inlet main pipe; 4243, water inlet branch; 4244, second water inlet branch; 425, outer bottom cover; 426, high temperature molten salt feed port; 427, first partition; 430, middle heat exchange shell; 4 31. Middle shell; 432. Protruding nozzle tube; 433. Second water inlet interface; 434. Molten salt discharge outlet; 435. Second top plate; 437. Second partition; 439. Protruding nozzle partition; 440. Capillary; 441. Bend pipe; 450. De-impurity assembly; 451. Threaded rod; 452. Nut; 453. Connecting rod; 454. Scraper ring; 4541. Notch; 460. Molten salt discharge pipe fitting; 461. Discharge branch pipe; 462. Discharge joint; 463. Discharge main pipe; 5. Water supply pump; 6. Make-up water tank; 7. Water treatment device. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] In the description of the present invention, it should be understood that the terms "opening", "upper", "lower", "thickness", "top", "middle", "length", "inside", "all around" and the like indicating orientation or positional relationship are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the components or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0039] According to the following Figure 1-Figure 14 A molten salt heat storage and steam supply system provided in an embodiment of the present invention is described.

[0040] Example 1. For this example, please refer to Figure 1-Figure 12 .

[0041] See also Figure 1 The embodiment of the present invention provides a molten salt heat storage and steam supply system, including a low-temperature molten salt tank 2, a high-temperature molten salt tank 1, a heat exchange module and a water supply module. The low-temperature molten salt tank 2 is used to store low-temperature molten salt. A delivery pipeline is installed between the low-temperature molten salt tank 2 and the high-temperature molten salt tank 1, and a low-temperature molten salt pump is provided. When the low-temperature molten salt pump is working, the molten salt in the low-temperature molten salt tank 2 can be pumped into the high-temperature molten salt tank 1. The high-temperature molten salt tank 1 has an electric heating module. A delivery pipeline is installed between the high-temperature molten salt tank 1 and the heat exchange module, and a high-temperature molten salt pump is provided. The water supply module can transport municipal water after treatment to the heat exchange module. In the heat exchange module, the high-temperature molten salt exchanges heat with water, so that the water forms water vapor for heating, and the molten salt after the temperature is reduced returns to the low-temperature molten salt tank 2.

[0042] In more detail, the detailed process of the system is divided into two stages, the first is the heat storage stage of the molten salt, and the second is the heat release stage of the molten salt. Specifically:

[0043] ① In the heat storage stage, the electric heating module can heat up the molten salt in the high-temperature molten salt tank 1 to form high-temperature molten salt:

[0044] ② In the heat release stage, the high-temperature molten salt pump starts, driving the molten salt to flow in the delivery pipeline until it reaches the heat exchange module. The water supply module can transport the municipal water after treatment to the heat exchange module. In the heat exchange module, the high-temperature molten salt exchanges heat with the water, so that the water forms water vapor for heating, and the molten salt with the temperature lowered returns to the low-temperature molten salt tank 2.

[0045] Preferably, the water supply module should supply softened water with sufficient pressure and flow into the heat exchanger.

[0046] Optionally, the molten salt uses a binary salt or a ternary salt.

[0047] Continue to refer to Figure 1The heat exchange module mentioned above actually includes a secondary molten salt heat exchanger 3 and a primary molten salt heat exchanger 4. The water and the high-temperature molten salt exchange twice to ensure the formation of steam. Specifically, the high-temperature molten salt in the high-temperature molten salt tank 1 passes through the secondary molten salt heat exchanger 3 and the primary molten salt heat exchanger 4 in turn and then returns to the low-temperature molten salt tank 2. The water in the water supply module passes through the primary molten salt heat exchanger 4 and the secondary molten salt heat exchanger 3 in turn and exchanges heat with the high-temperature molten salt to form water vapor.

[0048] In actual use, both the primary molten salt heat exchanger 4 and the secondary molten salt heat exchanger 3 mostly adopt shell and tube heat exchangers, in which high-temperature molten salt flows through the tube side and water to be exchanged flows through the shell side. However, at the water inlet, due to the low initial water temperature, the temperature of part of the high-temperature molten salt in the tube side (this part of the high-temperature molten salt refers to the molten salt close to the inner wall of the tube side) drops sharply, causing the molten salt to precipitate crystals. Long-term use causes the molten salt inlet of the tube side to be blocked, and the molten salt on the inner wall of the tube side is difficult to clean, especially for the primary molten salt heat exchanger 4.

[0049] To this end, the secondary molten salt heat exchanger 3 in the present invention adopts a shell and tube heat exchanger commonly used in the prior art, and the primary molten salt heat exchanger 4 provides the following solution, the primary molten salt heat exchanger 4 includes an outer tank shell 420, a middle heat exchange shell 430 and a thin tube 440, and a bracket 410 is arranged on the outer tank shell 420. For details, refer to Figure 2-Figure 5 Can understand better.

[0050] The main part of the outer tank shell 420 is the outer shell 421, and the middle heat exchange shell 430 is provided with one or more groups. Figure 4 Four groups of middle-layer heat exchange shells 430 are provided, which are arranged in the outer shell 421. The shell side of the middle-layer heat exchange shell 430 has water to be heat exchanged flowing from bottom to top. The capillary tubes 440 are distributed in the middle-layer heat exchange shell 430. High-temperature molten salt flows in the capillary tubes 440, so that the high-temperature molten salt can exchange heat with the water in the shell side of the middle-layer heat exchange shell 430 through the tube wall of the capillary tubes 440.

[0051] What is particularly important is that the high-temperature molten salt actually enters the outer shell 421 from the lower part of the outer shell 421, so that the shell wall of the middle heat exchange shell 430 exchanges heat with the high-temperature molten salt in the outer shell 421, forming a state in which the middle heat exchange shell 430 exchanges heat with the high-temperature molten salt in the capillary 440 on the one hand, and exchanges heat with the high-temperature molten salt in the outer shell 421 on the other hand, thereby increasing the heat exchange area of ​​the water in the shell side of the middle heat exchange shell 430, thereby improving the heat exchange efficiency.

[0052] Furthermore, the high-temperature molten salt in the above-mentioned capillary tube 440 is actually obtained by exchanging heat between the high-temperature molten salt in the outer shell 421 and the water in the shell side of the middle heat exchange shell 430 before entering the capillary tube 440, and the feeding position of the high-temperature molten salt into the capillary tube 440 should be higher than the position where the water to be heat exchanged enters the middle heat exchange shell 430, so that the water exchanged with the high-temperature molten salt entering the capillary tube 440 is the water that has been heat exchanged with the outer shell 421, so that the molten salt entering the capillary tube 440 will not produce crystallization, thereby avoiding blockage of the capillary tube 440.

[0053] It should be noted that since the water temperature initially entering the shell of the middle heat exchange shell 430 is relatively low, crystals will also precipitate from the high-temperature molten salt in the outer shell 421 close to the middle heat exchange shell 430. These crystals will adhere to the outer surface of the middle heat exchange shell 430, but since the crystals are located on the outer surface, it is more convenient to clean.

[0054] Therefore, in the molten salt heat storage and steam supply system provided by the embodiment of the present invention, when water exchanges heat with high-temperature molten salt, the high-temperature molten salt first exchanges heat with water outside the middle heat exchange shell 430, so that the crystal precipitation position is changed from the original pipe path to the outer surface of the middle heat exchange shell 430, which is convenient for cleaning. After the heat exchange is completed, the high-temperature molten salt enters the capillary 440 to exchange heat with water, and the water exchanged with the high-temperature molten salt entering the capillary 440 is the water that has been heat exchanged with the outer shell 421, so that the molten salt entering the capillary 440 will not produce crystallization, thereby avoiding blockage of the capillary 440 and ensuring that the capillary 440 can remain unobstructed.

[0055] Specifically, in order to achieve the above-mentioned purpose that the water exchanged by the high-temperature molten salt entering the capillary 440 is the water that has been heat-exchanged by the outer shell 421, refer to Figure 4-Figure 7 As shown, the middle heat exchange shell 430 here includes a middle shell 431 and a convex nozzle 432. The middle shell 431 is arranged in the outer shell 421 along the axial direction of the outer shell 421, and the convex nozzle 432 is arranged at the lower part of one side of the middle shell 431. There is an angle between the convex nozzle 432 and the outer shell 421, preferably the angle is 90°, and the lower end of the capillary 440 does not extend to the lowermost end of the middle shell 431, it only reaches the position of the convex nozzle 432, and its lower end An integrated bending tube 441 is provided at the end, and there is an angle between the bending tube 441 and the capillary tube 440, and the angle between the two is preferably 90°, so that the bending tube 441 can be accommodated in the convex nozzle tube 432, and a convex nozzle partition 439 is fixed in the convex nozzle tube 432, and a through hole opposite to the bending tube 441 is opened on the convex nozzle partition 439, so that the high-temperature molten salt in the outer shell 421 can enter the bending tube 441 through the convex nozzle tube 432 and the through hole, and then enter the capillary tube 440.

[0056] Preferably, a baffle commonly used in the prior art should also be provided in the middle shell 431 to extend the flow distance of water in the middle shell 431 .

[0057] Furthermore, a second water inlet interface 433 is fixedly provided on one side of the lower part of the middle shell 431. The second water inlet interface 433 is used for the water to be heat exchanged to enter the shell side of the middle shell 431, and there is a reserved length between the second water inlet interface 433 and the protruding nozzle tube 432. The water to be heat exchanged entering from the second water inlet interface 433 only exchanges heat with the high-temperature molten salt outside the middle shell 431 within the reserved length, and does not exchange heat with the high-temperature molten salt in the capillary 440.

[0058] Optionally, the above-mentioned reserved length is 1m-1.5m.

[0059] In this embodiment, the water within the reserved length can have sufficient heat exchange time with the high-temperature molten salt outside the middle shell 431 (the water entering the shell side of the middle shell 431 needs to flow upward for a length of 1m-1.5m before exchanging heat with the high-temperature molten salt in the capillary 440), ensuring that the temperature of the water exchanging heat with the high-temperature molten salt in the capillary 440 rises, thereby avoiding the blockage of the capillary 440 and the bent tube 441 due to low-temperature water.

[0060] Preferably, Figure 4 , Figure 8 and Fig.10 The upper end of the outer shell 421 is extended to the upper end of the middle shell 431, and an outer top cover 422 is fixedly provided at the upper end of the outer shell 421, and the upper end of the middle shell 431 passes through the outer top cover 422, and a first partition 427 is fixedly provided at the lower inner part of the outer shell 421, and the first partition 427 is higher than the height of the protruding nozzle tube 432. The first partition 427 is used to prevent the high-temperature molten salt in the outer shell 421 from continuously moving upward, so that the high-temperature molten salt in the outer shell 421 will no longer move upward after reaching the height of the protruding nozzle tube 432, and the space above the first partition 427 will not enter the high-temperature molten salt.

[0061] Of course, in fact, if the first partition 427 is not provided, the high-temperature molten salt in the lower part of the outer shell 421 can not only enter the convex nozzle 432, but also continue to move upward until it reaches the position of the outer top cover 422. This method can make the outer shell 421 full of high-temperature molten salt, which can further improve the heat exchange efficiency. However, compared with the provision of the first partition 427, it will cause a small amount of salt crystals to adhere to the upper outer surface of the middle shell 431, which will cause certain troubles for subsequent cleaning. On the other hand, if the first partition 427 is used, it is only necessary to clean the outer wall of the middle shell 431 below the first partition 427. The upper outer shell 421 can play a certain role in heat preservation of the middle shell 431, thereby avoiding the situation in which the water temperature is lowered due to the direct heat exchange between the water and water vapor in the middle shell 431 and the external environment through the shell wall of the middle shell 431.

[0062] Preferably, in order to facilitate the high-temperature molten salt to enter the outer shell 421, a high-temperature molten salt feed port 426 is provided at the lower portion of one side of the outer shell 421, and the high-temperature molten salt enters the outer shell 421 through the high-temperature molten salt feed port 426, that is, the high-temperature molten salt enters the outer shell 421 from the area near the lower end of the outer shell 421.

[0063] In addition, a corresponding water inlet pipe 424 should be provided. The water inlet pipe 424 is used to allow municipal water to enter the shell side of the middle shell 431. Figure 3 , Figure 4 and Fig. 9 As shown, the water inlet pipe 424 should be connected to the second water inlet interface 433, so that municipal water enters the second water inlet interface 433 and the shell side of the middle shell 431 through the water inlet pipe 424; however, based on the installation position of the above-mentioned high-temperature molten salt feed port 426, the position of the water inlet pipe 424 is higher than the high-temperature molten salt feed port 426, and the water inlet pipe 424 here includes a water inlet main pipe 4242, and the water inlet main pipe 4242 is an arc pipe, and one end of the arc pipe is provided with an integrated first water inlet interface 4241, and the area of ​​the water inlet main pipe 4242 opposite to the second water inlet interface 433 is provided with a water inlet branch pipe 4243, and the end of the water inlet branch pipe 4243 close to the outer shell 421 is fixedly provided with a second water inlet branch pipe 4244, and the outer shell 421 is provided with a butt pipe 4211 connected to the second water inlet branch pipe 4244, and the other end of the butt pipe 4211 is fixedly connected to the second water inlet interface 433.

[0064] In this embodiment, the first water inlet interface 4241 is connected to the water supply module, and the water flows through the first water inlet interface 4241, the water inlet main pipe 4242, the water inlet branch pipe 4243, the water inlet second branch pipe 4244, the docking pipe 4211, and the second water inlet interface 433 and then enters the shell side of the middle shell 431.

[0065] In addition, a drainage pipe 423 is provided on the outer periphery of the upper part of the middle shell 431 to discharge the water after heat exchange. The water after heat exchange continues to exchange heat after entering the secondary molten salt heat exchanger 3 to form water vapor.

[0066] Combination Figure 5 and Figure 6 As shown, since the height of the second water inlet interface 433 is greater than the height of the high-temperature molten salt feed port 426, there is actually a distance between the second water inlet interface 433 and the lowermost end of the middle shell 431. In order to prevent the water entering the middle shell 431 from the second water inlet interface 433 from forming dead water below the second water inlet interface 433, a second partition 437 is provided near the lower end of the middle shell 431. The second partition 437 is used to isolate the middle shell 431 into a space with high-temperature molten salt and a space without high-temperature molten salt. The space above the second partition 437 is a space with high-temperature molten salt, and the space below the second partition 437 is a space without high-temperature molten salt.

[0067] In addition, if Figure 2 and Figure 3 A molten salt discharge port 434 is provided at the upper end of the middle shell 431 , and a plurality of molten salt discharge ports 434 are connected to molten salt discharge pipe fittings 460 , and the discharge port of the molten salt discharge pipe fittings 460 is connected to the feed port of the low-temperature molten salt tank 2 .

[0068] In addition, a second top plate 435 is fixedly provided at the upper end of the middle shell 431 . A through hole is provided on the second top plate 435 at a position opposite to the capillary 440 , so that the molten salt in the capillary 440 can enter the molten salt discharge pipe 460 .

[0069] Specifically, the molten salt discharge pipe fitting 460 includes a discharge branch pipe 461 located at the upper end of the middle shell 431, a discharge joint 462 is arranged between the discharge branch pipe 461 and the molten salt discharge pipe fitting 460, and a discharge main pipe 463 is arranged at the other end of the discharge branch pipe 461, and the discharge main pipe 463 is connected to the feed port of the low-temperature molten salt tank 2.

[0070] Furthermore, in order to ensure the sealing of the lower end of the outer shell 421, an outer bottom cover 425 is fixed to the lower end of the outer shell 421 through a flange, and the lower end of the middle shell 431 is installed on the outer bottom cover 425 through a flange. This method also ensures the sealing of the lower end of the middle shell 431.

[0071] like Figure 4 and Fig. 9As shown, in fact, in this embodiment, the crystals precipitated by the molten salt when it is cooled are attached to the outside and bottom of the middle shell 431, so in order to reduce the frequency of cleaning by the operator, a debris removal component 450 is also provided here, and the debris removal component 450 includes a scraper ring 454 and a threaded rod 451, the scraper ring 454 is sleeved on the lower periphery of the middle shell 431, and the scraper ring 454 is provided with a notch 4541 in the area opposite to the second water inlet interface 433, the threaded rod 451 is installed in the outer shell 421 along the axial rotation of the outer shell 421, and a nut 452 is threadedly connected to the threaded rod 451, a connecting rod 453 is provided between the nut 452 and the scraper ring 454, and a motor for driving the threaded rod 451 to rotate is provided at the upper end of the outer top cover 422.

[0072] In this embodiment, when the threaded rod 451 rotates, the nut 452 will produce axial movement, and then the nut 452 can drive the scraper ring 454 to move axially through the connecting rod 453. The scraper ring 454 can scrape off the salt crystals on the outer surface of the middle shell 431, and the salt crystals are re-mixed into the high-temperature molten salt and melted again.

[0073] It should be noted that, since the temperature of the high-temperature molten salt in the central area of ​​the outer shell 421 (the area where the threaded rod 451 is located) is relatively high (the central area is far away from the middle shell 431, so the temperature is relatively high), crystals will not be generated in the central area, so that the outer surface of the threaded rod 451 is not worn by crystals.

[0074] like Figure 1 The water supply module in the molten salt heat storage steam supply system provided in the embodiment of the present invention includes a water treatment device 7, a water supply tank 6 and a water supply pump 5. The water treatment device 7 is used to treat municipal water. The water supply tank 6 is used to store water treated by the water treatment device 7 to form soft water without impurities. The water supply pump 5 is used to transport water to the primary molten salt heat exchanger 4 (in essence, the water supply pump 5 is directly connected to the water inlet pipe 424).

[0075] When in use (when working), ① during the heat storage stage, the electric heating module can heat up the molten salt in the high-temperature molten salt tank 1 to form high-temperature molten salt:

[0076] ② In the heat release stage, the high-temperature molten salt pump is started, driving the molten salt to flow in the delivery pipeline, and passes through the secondary molten salt heat exchanger 3 and the primary molten salt heat exchanger 4 in turn. The water supply module transports the municipal water after treatment, and reaches the primary molten salt heat exchanger 4 and the secondary molten salt heat exchanger 3 in turn.

[0077] During the heat release stage, the heat exchange process between water and high-temperature molten salt in the primary molten salt heat exchanger 4 is as follows: Fig.11 :

[0078] 1) Flow direction of molten salt: the high-temperature molten salt discharged from the secondary molten salt heat exchanger 3 enters the outer shell 421 through the high-temperature molten salt feed port 426, gradually moves upward in the outer shell 421, and gradually enters the capillary 440 of the middle shell 431 through the protruding nozzle 432, and gradually flows upward along the capillary 440, and finally is discharged from the molten salt discharge pipe 460 to the interior of the low-temperature molten salt tank 2;

[0079] 2) Water flow direction: The water source from the water supply module enters the shell side of the middle shell 431 through the water inlet pipe 424 and the second water inlet interface 433, and gradually moves upward along the shell side of the middle shell 431 until it is discharged from the drainage pipe 423 and enters the secondary molten salt heat exchanger 3 for secondary heat exchange, thereby forming steam;

[0080] 3) Heat exchange between molten salt and water in the primary molten salt heat exchanger 4: The molten salt in the outer shell 421 first exchanges heat with the water below the middle shell 431, thereby increasing the water temperature. The water with increased water temperature moves upward in the shell side of the middle shell 431 until it reaches the position of the capillary tube 440 and the bent tube 441. Only then will the molten salt in the capillary tube 440 and the bent tube 441 exchange heat with the water.

[0081] In addition, there should also be a cleaning stage. During cleaning, the motor drives the threaded rod 451 to rotate, and then the scraper ring 454 can be driven to move up and down through the nut 452. The scraper ring 454 can scrape off the crystals on the outer surface of the middle shell 431 to avoid heat exchange between the water in the shell side of the middle shell 431 and the high-temperature molten salt in the outer shell 421.

[0082] Example 2. For this example, please refer to Fig.13 and Fig.14 .

[0083] The difference between this embodiment and the first embodiment is that the upper end of the outer shell 421 here extends to above the protruding nozzle 432, and does not extend to a position close to the upper end of the middle shell 431, that is, the length of the outer shell 421 in this embodiment is less than the length of the outer shell 421 in the first embodiment, and an outer top cover 422 is fixedly provided at the upper end of the outer shell 421. This method can also make the high-temperature molten salt between the outer shell 421 and the middle shell 431 flow only in the low-position area.

[0084] It should be noted that when the shorter outer shell 421 in this embodiment is used, the portion of the middle shell 431 located outside the outer shell 421 should be wrapped with an insulation sleeve to avoid the water temperature from dropping due to the water and water vapor in the middle shell 431 directly exchanging heat with the external environment through the shell wall of the middle shell 431.

[0085] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0086] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A molten salt heat storage steam supply system, characterized in that: include: Low temperature molten salt tank (2); A high-temperature molten salt tank (1), wherein the high-temperature molten salt tank (1) is used to receive the low-temperature molten salt in the low-temperature molten salt tank (2) and heat the low-temperature molten salt; and a secondary molten salt heat exchanger (3) and a primary molten salt heat exchanger (4), the high-temperature molten salt in the high-temperature molten salt tank (1) passes through the secondary molten salt heat exchanger (3) and the primary molten salt heat exchanger (4) in sequence and then returns to the low-temperature molten salt tank (2), and the water in the water supply module passes through the primary molten salt heat exchanger (4) and the secondary molten salt heat exchanger (3) in sequence and exchanges heat with the high-temperature molten salt to form water vapor; Wherein, the primary molten salt heat exchanger (4) comprises: Outer shell (421); A middle heat exchange shell (430), wherein the middle heat exchange shell (430) is provided with one or more groups, the middle heat exchange shell (430) is arranged in the outer shell (421), and the shell side in the middle heat exchange shell (430) has water to be heat exchanged flowing from bottom to top; Thin tubes (440), the thin tubes (440) are distributed in the middle heat exchange shell (430); The high-temperature molten salt enters the outer shell (421) at the lower part of the outer shell (421), and exchanges heat with the water to be exchanged in the shell side of the middle heat exchange shell (430) through the middle heat exchange shell (430), and the high-temperature molten salt can enter the capillary tube (440) and exchange heat with the water to be exchanged in the middle heat exchange shell (430), and the position where the high-temperature molten salt enters the capillary tube (440) is higher than the position where the water to be exchanged enters the middle heat exchange shell (430); The middle layer heat exchange shell (430) comprises a middle layer shell (431) and a protruding nozzle (432), wherein the middle layer shell (431) is arranged in the outer layer shell (421) along the axial direction of the outer layer shell (421), and the protruding nozzle (432) is arranged at a lower part of one side of the middle layer shell (431); A bending tube (441) is provided at the lower end of the capillary tube (440), an angle is formed between the bending tube (441) and the capillary tube (440), and the bending tube (441) is located in the convex nozzle tube (432), a convex nozzle partition (439) is fixed in the convex nozzle tube (432), and a through hole opposite to the bending tube (441) is formed on the convex nozzle partition (439); A second water inlet interface (433) is fixedly provided on one side of the lower portion of the middle shell (431), the second water inlet interface (433) being used for the water to be heat exchanged to enter, and a reserved length is provided between the second water inlet interface (433) and the convex nozzle tube (432); A first baffle (427) is fixedly disposed at the lower inner portion of the outer shell (421). The first baffle (427) is higher than the height of the protruding nozzle (432). The first baffle (427) can prevent the high-temperature molten salt in the outer shell (421) from continuously moving upward.

2. A molten salt heat storage steam supply system according to claim 1, characterized in that: The upper end of the outer shell (421) extends to the upper end of the middle shell (431), and an outer top cover (422) is fixedly disposed on the upper end of the outer shell (421), and the upper end of the middle shell (431) passes through the outer top cover (422).

3. The molten salt heat storage steam supply system according to claim 1, characterized in that: The upper end of the outer shell (421) extends to above the protruding nozzle tube (432), and an outer top cover (422) is fixedly provided at the upper end of the outer shell (421).

4. A molten salt heat storage steam supply system according to claim 2 or 3, characterized in that: A high-temperature molten salt feed inlet (426) is provided at a lower portion of one side of the outer shell (421), and the high-temperature molten salt enters the outer shell (421) through the high-temperature molten salt feed inlet (426); The upper end of the middle shell (431) is provided with a molten salt discharge outlet (434), a plurality of the molten salt discharge outlets (434) are connected to molten salt discharge pipe fittings (460), and the discharge ports of the molten salt discharge pipe fittings (460) are connected to the feed port of the low-temperature molten salt tank (2); A second top plate (435) is fixedly provided at the upper end of the middle shell (431), and a through hole is provided on the second top plate (435) at a position opposite to the capillary tube (440) for allowing the molten salt in the capillary tube (440) to enter the molten salt discharge pipe (460).

5. A molten salt heat storage steam supply system according to claim 4, characterized in that: A water inlet pipe (424) is provided at the lower part of the middle shell (431), and the water inlet pipe (424) comprises a water inlet main pipe (4242). The water inlet main pipe (4242) is an arc-shaped pipe, and a water inlet branch (4243) is provided in an area on the water inlet main pipe (4242) opposite to the second water inlet interface (433). A second water inlet branch pipe (4244) is fixedly provided at one end of the water inlet branch (4243) close to the outer shell (421), and a butt pipe (4211) connected to the second water inlet branch pipe (4244) is provided on the outer shell (421), and the other end of the butt pipe (4211) is fixedly connected to the second water inlet interface (433); A drainage pipe (423) is provided on the periphery of the upper portion of the middle shell (431).

6. A molten salt heat storage steam supply system according to claim 5, characterized in that: A second partition (437) is provided near the lower end of the middle shell (431), and the second partition (437) is used to isolate the middle shell (431) into a space with high-temperature molten salt and a space without high-temperature molten salt. The space above the second partition (437) is the space with high-temperature molten salt, and the space below the second partition (437) is the space without high-temperature molten salt.

7. A molten salt heat storage steam supply system according to claim 6, characterized in that: An outer bottom cover (425) is fixed to the lower end of the outer shell (421) via a flange; The lower end of the middle shell (431) is mounted on the outer bottom cover (425) via a flange.

8. The molten salt heat storage steam supply system according to claim 7, characterized in that: Also included is a debris removal component (450), the debris removal component (450) comprising: A scraper ring (454), the scraper ring (454) being sleeved on the lower periphery of the middle shell (431), and a notch (4541) is provided on the scraper ring (454) in an area opposite to the second water inlet interface (433); A threaded rod (451) is rotatably mounted in the outer shell (421) along the axial direction of the outer shell (421), and a nut (452) is threadedly connected to the threaded rod (451), and a connecting rod (453) is provided between the nut (452) and the scraper ring (454).

9. The molten salt heat storage steam supply system according to claim 1, characterized in that: The water supply module comprises: A water treatment device (7), wherein the water treatment device (7) is used for treating municipal water; A water replenishment tank (6), wherein the water replenishment tank (6) is used to store water treated by the water treatment device (7); A water feed pump (5), wherein the water feed pump (5) is used to transport water to the first-stage molten salt heat exchanger (4).

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