A salt dissolving device

Abstract

This invention relates to a salt dissolving device, comprising an outer shell, an inner shell, a filter device, and a molten salt pump. The outer shell is provided with a heating element and a feeding port. The heating element is at least located on the outer peripheral wall of the outer shell. A jacketed salt cavity is formed between the inner peripheral wall of the outer shell and the outer peripheral wall of the inner shell. A bottom salt cavity is formed between the lower end of the inner shell and the bottom wall of the outer shell. The feeding port is provided corresponding to the jacketed salt cavity. The heating element is used to heat and melt the solid molten salt in the jacketed salt cavity into liquid molten salt. The filter device is located between the jacketed salt cavity and the bottom salt cavity or in the bottom salt cavity. The filter device is used to separate the liquid molten salt from the solid molten salt. The molten salt pump extends into the bottom salt cavity to discharge the liquid molten salt that enters the bottom salt cavity from the jacketed salt cavity.

Description

Technical Field

[0001] This invention relates to the field of molten salt thermal storage technology, and more particularly to a salt melting device. Background Technology

[0002] Molten salt melting is a crucial procedure before molten salt equipment can operate. Through this process, molten salt changes from a solid to a liquid state and enters the molten salt heat storage system to begin circulation. Molten salt melting is typically carried out by specialized melting equipment. Most existing melting equipment uses tanks to hold and heat the molten salt; for example, some equipment uses electric heat tracing installed on the outside of the tank. Specifically, solid molten salt is spread and piled inside the tank, forming a large volume of solid molten salt. Then, electric heat tracing is used to heat the outside of the tank, transferring heat to the molten salt through radiation, thus melting the salt. Furthermore, in the initial melting stage of the seed salt, manual entry into the tank is required to spread and level the solid molten salt.

[0003] However, in practical applications, it has been found that the molten salt near the tank wall in the solid molten salt pile melts into a liquid state first. For example, when the tank wall is equipped with electric heating, the molten salt near the tank wall in the solid molten salt pile melts into a liquid state first. The liquid molten salt flows into the gaps between the solid molten salt particles that are farther away from the tank wall, leaving their original position. After the liquid molten salt flows into the gaps between the solid molten salt particles, the solid molten salt tends to clump together, making it difficult for the solid molten salt particles to flow and replenish the area near the tank wall. This results in a cavity area forming in the part of the solid molten salt pile near the tank wall. This cavity area separates the tank wall from the main body of the solid molten salt pile, making it difficult for the tank to conduct heat to the solid molten salt pile. The heat transfer effect is greatly reduced, the total salt melting time is greatly increased, and the overall salt melting efficiency of the salt melting device is reduced. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a salt melting device. By improving the structure of the salt melting device, a jacketed salt cavity is formed, allowing solid molten salt particles to melt upon heating within the jacketed salt cavity. The solid molten salt particles accumulate in the jacketed salt cavity according to the shape of the cavity, ensuring that the solid molten salt pile does not have a central part far from the outer shell. All solid molten salt particles are close to the outer shell and can be heated efficiently, thus solving the problem in the prior art where the overall salt melting time is too long because the central part of the solid molten salt pile is difficult to heat well.

[0005] Specifically, the present invention provides a salt dissolving device, comprising an outer shell, an inner shell, a filter device, and a molten salt pump. The outer shell is provided with a heating element and a feeding port. The heating element is at least disposed on the outer peripheral wall of the outer shell. A jacketed salt cavity is formed between the inner peripheral wall of the outer shell and the outer peripheral wall of the inner shell. A bottom salt cavity is formed between the lower end of the inner shell and the bottom wall of the outer shell. The feeding port is disposed corresponding to the jacketed salt cavity. The heating element is used to heat and melt the solid molten salt in the jacketed salt cavity into liquid molten salt. The filter device is disposed between the jacketed salt cavity and the bottom salt cavity or in the bottom salt cavity. The filter device is used to separate the liquid molten salt from the solid molten salt. The molten salt pump extends into the bottom salt cavity to discharge the liquid molten salt that enters the bottom salt cavity from the jacketed salt cavity.

[0006] According to one aspect of the present invention, the salt dissolving device further includes a spiral baffle plate, wherein the feeding port is disposed corresponding to the uppermost end of the spiral baffle plate, and the spiral baffle plate is disposed in the jacketed salt cavity to form a flow channel for the solid molten salt to flow spirally downward.

[0007] According to one aspect of the invention, a portion of the feeding port corresponds to the jacketed salt chamber, and another portion corresponds to the upper opening of the inner shell, so as to feed a portion of solid molten salt into liquid molten salt through the inner shell.

[0008] According to one aspect of the invention, the filtration device is disposed at the junction of the jacketed salt chamber and the bottom salt chamber, so that liquid molten salt flows into the bottom salt chamber through the filtration device while solid molten salt particles remain in the jacketed salt chamber.

[0009] According to one aspect of the invention, the filter device is cylindrical, connected to the lower end of the inner housing and extending to the lower end cap of the outer housing, and has through holes around its perimeter to allow liquid molten salt in the bottom salt chamber located around the periphery of the filter device to flow into the enclosed area of ​​the filter device.

[0010] According to one aspect of the invention, the system further includes a salt outlet pipeline and a return pipeline, the salt outlet pipeline being connected to the molten salt pump, and the return pipeline being connected to the salt outlet pipeline and leading to the jacketed salt chamber, so as to deliver a portion of the liquid molten salt into the jacketed salt chamber.

[0011] According to one aspect of the invention, the inner housing is provided with an auxiliary heating element and / or a stirrer, which are disposed inside the inner housing from top to bottom.

[0012] According to one aspect of the invention, the peripheral wall of the inner shell is made of a metallic material so that the liquid molten salt within the inner shell conducts heat to the jacketed salt cavity.

[0013] According to one aspect of the invention, the bottom center of the outer casing is provided with a vent for discharging solid molten salt.

[0014] According to one aspect of the invention, the heating element is further disposed on the outer bottom wall of the outer housing to heat the bottom salt cavity.

[0015] Compared with the prior art, the present invention provides a salt melting device with a jacketed structure. An inner shell and an outer shell form a jacketed salt cavity. A heating element is provided on the outer peripheral wall of the outer shell, so that the molten salt is melted in the jacketed salt cavity. This eliminates the middle part of the molten salt pile in the salt melting furnace that is far away from the heating element, thus eliminating the cold end in the middle. The molten salt can be efficiently heated by the external heating element in the jacketed salt cavity, thereby improving the salt melting efficiency. Attached Figure Description

[0016] The accompanying drawings, which illustrate various embodiments of the present invention, are described below. In the drawings, the same reference numerals denote the same parts. The drawings are not necessarily drawn to scale, and some parts may be enlarged to show the details of the present invention.

[0017] Figure 1 An overview diagram of the salt-dissolving apparatus according to the present invention is shown; Figure 2 A detailed internal view of the salt-dissolving apparatus according to the present invention is shown, illustrating the construction of the spiral baffle and a first arrangement embodiment of the filtration device; Figure 3 A detailed internal view of the salt-dissolving apparatus according to the present invention is shown, illustrating the construction of the spiral baffle and a second arrangement embodiment of the filtration device; Figure 4 A detailed internal view of the salt-dissolving apparatus according to the present invention is shown, illustrating the construction of the spiral baffle and a third arrangement embodiment of the filtration device; Figure 5 A diagram of another embodiment of the salt-dissolving apparatus according to the present invention is shown, wherein an auxiliary heating element and a stirrer are shown extending from top to bottom inside the inner shell; Figure 6 A diagram showing another embodiment of the salt-dissolving apparatus according to the present invention is shown, in which an embodiment employs... Figure 1 The salt-dissolving device is connected to a low-level collection tank at the bottom of the drain port to complete the salt-dissolving operation. Detailed Implementation

[0018] Specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0019] Figure 1An overview diagram of the salt-dissolving device according to the present invention is shown. As shown, the salt-dissolving device of the present invention can be a vertical storage tank type salt-dissolving device, which includes an outer shell 1 and an inner shell 2. The inner shell 2 forms a cylindrical body with an opening at the top. A jacketed salt cavity 12 is formed between the inner peripheral wall of the outer shell 1 and the outer peripheral wall of the inner shell 2. A bottom salt cavity 13 is formed between the lower end of the inner shell 2 and the bottom wall of the outer shell 1. The peripheral sidewall of the inner shell 2 can be made of metal, thereby having good thermal conductivity, allowing the liquid molten salt temporarily stored in the inner shell 2 to transfer its own heat from the inside to the outside to the molten salt in the jacketed salt cavity 12, improving the salt-dissolving effect in the jacketed salt cavity 12, and improving the heating uniformity in the jacketed salt cavity 12.

[0020] A heating element 7 is provided on the outer side of the outer casing 1, such as... Figure 1 As shown, the heating element 7 can be horizontally arranged on the outside of the outer housing 1 in the form of an electric heating device, although other forms of heating elements are also possible. The heating element 7 can heat at least the peripheral sidewalls of the outer housing 1, and more preferably the bottom wall of the outer housing 1, so that both the jacketed salt chamber 12 and the bottom salt chamber 13 can receive efficient radiant heating, thereby improving the salt-melting efficiency of the salt-melting device for molten salt.

[0021] A spiral plate-type jacket structure 6 is provided along the height direction in the jacketed salt cavity 12. Specifically, the spiral plate-type jacket structure 6 includes a spiral baffle 6a, which extends spirally downwards around the outer peripheral wall of the inner shell 2 to the bottom salt cavity 13 in the height direction to form a spiral flow channel for the solid molten salt to flow spirally downwards, such as from... Figures 2-4 As shown more clearly in the diagram. At least one feeding port 5 can be provided at the upper part of the salt-melting device. This feeding port 5 can be chimney-shaped, funnel-shaped, or other suitable shapes. The feeding port 5 corresponds to the jacketed salt chamber 12 and is aligned with the uppermost end of the spiral baffle 6a. Solid molten salt falls from the feeding port 5 to the uppermost end of the spiral baffle 6a and subsequently fills the entire spiral flow channel of the spiral baffle 6a. Because the salt-melting speed is not so fast, the molten salt waiting to be extracted at the lower part of the salt-melting device will block the continuous rapid fall of the molten salt in the spiral flow channel. Therefore, the spiral flow channel is always filled with solid molten salt, and the molten salt in the spiral flow channel gradually slides downwards. Furthermore, the spiral baffle 6a can be welded to the inner shell 2 and the outer shell 1. This baffle structure supports the inner shell 2 and simultaneously conducts heat from the outer shell 1 to the inner shell, thereby increasing the heat transfer area.

[0022] A filter device 9 is installed in the salt melting device to separate the heated liquid molten salt from the solid molten salt. A molten salt pump 4 extends from top to bottom through the inner shell 2 to discharge the liquid molten salt. The filter device 9 can be a flat filter plate or a cylindrical filter element with several filter holes. It is positioned between the jacketed salt chamber 12 and the bottom salt chamber 13, or within the bottom salt chamber 13, to block solid molten salt while allowing liquid molten salt to pass through, thus temporarily storing the solid molten salt for continued heating. The molten salt pump is preferably a submersible pump. Figures 2 to 4 Three different embodiments of the filter device 9 are shown.

[0023] exist Figure 2 In the first embodiment of the filter device 9 shown, the filter device 9 is a flat filter plate with a plurality of filter holes. The filter device 9 is located at the lower port of the inner housing 2. Even if the jacketed salt chamber 12 and the bottom salt chamber 13 are filled with molten salt, only the molten liquid salt can pass through the filter device 9 and enter the interior of the inner housing 2, while the solid molten salt is blocked by the filter device 9. In this embodiment, the molten salt pump 4 extends into the lower end of the inner housing 2 to pump molten salt, and the filter device 9 is located below the molten salt pump 4 to protect the molten salt pump 4.

[0024] exist Figure 3 In the second embodiment of the filter device 9 shown, the filter device 9 is a flat filter plate with a plurality of filter holes. The filter device 9 is located at the interface between the jacketed salt chamber 12 and the bottom salt chamber 13. Solid molten salt accumulates in the jacketed salt chamber 12, while molten salt flows into the bottom salt chamber 13. Since it needs to cover the entire interface between the jacketed salt chamber 12 and the bottom salt chamber 13, this filter device 9 is more efficient than... Figure 2 The filtration device has a larger surface area. In this embodiment, the molten salt pump 4 can extend into the bottom salt chamber 13 to pump liquid molten salt.

[0025] exist Figure 4 In the third embodiment of the filter device 9 shown, the filter device 9 is a cylindrical filter element connected to the lower part of the inner shell 2. The cylindrical filter element has the same size as the inner shell 2 and is coaxial. The filter device 9 extends all the way to the lower end of the outer shell 1. The cylindrical peripheral wall of the filter device 9 has a circular through hole, and there is a semi-circular through hole at the connection with the lower end. This can prevent a large amount of solid molten salt from entering the inner shell 2, while only liquid molten salt can enter the enclosed area of ​​the inner shell 2.

[0026] Those skilled in the art will understand that the filter device 9 may have other structural configurations and may be installed in other locations of the salt dissolving device, all of which fall within the scope of the present invention.

[0027] Let's go back and continue referring to... Figure 1The salt dissolving device also includes a salt outlet pipe 3, to which liquid molten salt is pumped by a molten salt pump 4, such as... Figure 1 As shown in the enlarged view, the salt outlet pipe 3 can be further branched into two branches: the finished salt outlet pipe 3c and the return pipe 3d. Valves 3a and 3b can be installed on both the finished salt outlet pipe 3c and the return pipe 3d. The finished salt outlet pipe 3c outputs the finished salt, while the return pipe 3d sends a portion of the liquid molten salt into the jacketed salt chamber 12 through the molten salt return port 14. This accelerates the melting rate of the solid molten salt particles in the jacketed salt chamber 12. Thus, by introducing forced circulation of liquid molten salt, the dominant heat transfer mechanism in the traditional static salting process is changed. Specifically, the high-temperature liquid molten salt in the inner shell 2 is pumped back to the unmelted solid salt region through the return pipe 3d. Utilizing the kinetic energy and sensible heat of the flowing working fluid, the thermally resistive interface layer formed on the surface of the solid salt due to initial melting is directly destroyed and eliminated. This transforms the inefficient conductive thermal resistance between solid-solid and solid-wall surfaces into efficient direct contact convective heat transfer between the high-temperature liquid and solid particles. This process significantly enhances the rate and uniformity of heat transport to the solid core, fundamentally solving the bottleneck in salt melting speed caused by the limited thermal conductivity of the molten salt itself. Valves 3a and 3b can be opened or closed to control the output of finished salt and the feeding of liquid molten salt to the jacketed salt chamber 12 as needed. As an example, valve 3a can be a shut-off valve, and valve 3b can be an on / off valve.

[0028] At the bottom of the outer casing 1 of the salt dissolving device, preferably at the center of the bottom, there is a vent 8 for discharging residual molten salt that the pump could not extract after the salt dissolving process is completed. This vent 8 also has other functions, which will be described later.

[0029] A portion of the feeding port 5 can be aligned with the upper opening of the inner shell 2, and another portion of the feeding port 5 can be aligned with the uppermost end of the spiral baffle 6a of the jacketed salt chamber 12. In the initial stage of salt melting, solid molten salt is fed from the feeding port 5 into the jacketed salt melting chamber 12, thereby performing preliminary melting of the seed salt. When there is liquid molten salt in the inner shell 2, at least a portion of the solid molten salt can be fed into the inner shell 2 through the feeding port 5, thereby using the liquid molten salt in the inner shell 2 to accelerate the melting of the solid molten salt. Those skilled in the art will understand that, alternatively, two feeding ports 5 can be provided, one aligned with the inner shell 2 and the other aligned with the uppermost end of the spiral baffle 6a, or a branch line and valve can be used in one feeding port 5 to control the flow, allowing solid molten salt to be fed into the inner shell 2 or the jacketed salt chamber 12 as needed.

[0030] Figure 5 A diagram showing another embodiment of the salt-dissolving apparatus according to the present invention is shown. Figure 5 Implementation examples and Figure 1The embodiments are largely the same, except that an auxiliary heating element 10, such as an electric heating tube, is provided in the inner shell 2. This auxiliary heating element 10 can be installed in the inner shell 2 from top to bottom, just like the molten salt pump 4, to further heat the liquid molten salt in the inner shell 2. This prevents the liquid molten salt in the inner shell 2 (which has already been melted and is temporarily stored in the inner shell 2 to await pumping) from solidifying due to heat conduction to the jacketed salt cavity. It also improves the heating effect of the liquid molten salt in the inner shell 2 on the solid molten salt in the jacketed salt cavity 12, thereby improving the melting efficiency. Moreover, it makes the jacketed salt cavity 12 subject to dual heating from the outside to the inside and from the inside to the outside, which further reduces the problem of uneven heating effect at the near end and far end, and improves the temperature uniformity of the jacketed salt cavity 12. In addition to the auxiliary heating element 10, a stirrer 11 can be further provided. The stirrer 11 is also installed from top to bottom inside the inner shell 2 and extends below the surface of the liquid molten salt. It stirs the liquid molten salt to improve temperature uniformity and prevent local overheating from damaging the auxiliary heating element 10 and the inner shell 2.

[0031] Figure 6 A diagram showing another embodiment of the salt-dissolving apparatus according to the present invention is shown, in which an embodiment employs... Figure 1 The salt-dissolving device's bottom drain port connects to a low-level collection tank to complete the salt-dissolving operation. (As previously mentioned...) Figure 1 As described, a drain port 8 is provided at the center of the bottom of the outer shell 1 of the vertical storage tank of the salt-dissolving device according to the present invention. Its function is to discharge residual molten salt that the pump cannot extract after the salt-dissolving process is completed. However, when the vertical storage tank of the salt-dissolving device is too tall, the molten salt at the top can be removed, allowing the molten salt to be discharged first through the drain port 8 by gravity. Figure 6 In the low-level collection tank 15 shown, a small pump 16 installed on the ground draws molten salt from the low-level collection tank 15 and pumps the molten salt into the aforementioned molten salt outlet pipe 17, which has the same structure and function.

[0032] The salt-making process of the salt-making apparatus according to the present invention is described below.

[0033] Phase 1: Initial Phase At the initial stage of salt melting, the jacketed salt cavity 12 is filled with solid molten salt particles after feeding. The heating element 7 heats the outer shell 1, which then conducts heat to the jacketed salt cavity 12, causing the solid molten salt particles to gradually melt. Initially, the solid molten salt particles are basically in a state of temporary storage in the jacketed salt cavity 12, and the molten salt particles will clump together after initial heating, so they will not fall immediately and can be fully heated in the jacketed salt cavity 12, increasing the melting rate. When some of the molten salt has melted into a liquid state, the liquid molten salt begins to flow downwards, at which point additional feeding can be done.

[0034] Phase Two: Continuous Salt Processing Phase After the initial stage, most of the solid molten salt in the jacketed salt chamber 12 has turned into liquid molten salt. The liquid molten salt can be discharged without activating the molten salt pump 4, allowing a sufficient amount of liquid molten salt to remain in the jacketed salt chamber 12. At this point, the liquid molten salt can be fed in and pumped simultaneously. This allows the solid molten salt particles to be directly added to the liquid molten salt, significantly increasing the melting rate, and also enables continuous salt production and liquid salt output.

[0035] In most existing technologies, the solid molten salt in the salt-melting tank needs to be completely melted before it can be pumped out for use all at once. Therefore, the salt-melting mode is a batch mode, and the molten salt system needs to wait for a long time for the liquid molten salt. However, the present invention uses continuous salt-melting, which eliminates the need to supply liquid molten salt in batches, thus greatly improving production efficiency.

[0036] In the description of this invention, it should be understood that the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0037] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments.

[0038] For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A salt dissolving device, characterized in that, The device includes an outer shell, an inner shell, a filter device, and a molten salt pump. The outer shell is equipped with a heating element and a feeding port. The heating element is located at least on the outer peripheral wall of the outer shell. A jacketed salt cavity is formed between the inner peripheral wall of the outer shell and the outer peripheral wall of the inner shell. A bottom salt cavity is formed between the lower end of the inner shell and the bottom wall of the outer shell. The feeding port is located corresponding to the jacketed salt cavity. The heating element is used to heat and melt the solid molten salt in the jacketed salt cavity into liquid molten salt. The filter device is located between the jacketed salt cavity and the bottom salt cavity or in the bottom salt cavity. The filter device is used to separate the liquid molten salt from the solid molten salt. The molten salt pump extends into the bottom salt cavity to discharge the liquid molten salt that enters the bottom salt cavity from the jacketed salt cavity.

2. The salt dissolving device as described in claim 1, further comprising a spiral baffle plate, wherein the feeding port is disposed corresponding to the uppermost end of the spiral baffle plate, and the spiral baffle plate is disposed in the jacketed salt cavity to form a flow channel for the solid molten salt to flow downwards in a spiral.

3. The salt dissolving apparatus as claimed in claim 1, wherein a portion of the feeding port corresponds to the jacketed salt chamber and another portion corresponds to the upper opening of the inner shell, so as to feed a portion of solid molten salt into liquid molten salt through the inner shell.

4. The salt dissolving device as claimed in claim 1, wherein the filter device is disposed at the junction of the jacketed salt chamber and the bottom salt chamber, so that liquid molten salt flows into the bottom salt chamber through the filter device while solid molten salt particles remain in the jacketed salt chamber.

5. The salt dissolving device as claimed in claim 1, wherein the filter device is cylindrical, connected to the lower end of the inner shell and extending to the lower end cap of the outer shell, and has through holes around its perimeter to allow liquid molten salt in the bottom salt chamber located around the filter device to flow into the enclosed area of ​​the filter device.

6. The salt dissolving apparatus as claimed in claim 1, further comprising a salt outlet pipeline and a return pipeline, wherein the salt outlet pipeline is connected to the molten salt pump, and the return pipeline is connected to the salt outlet pipeline and leads to the jacketed salt chamber, so as to send a portion of the liquid molten salt into the jacketed salt chamber.

7. The salt dissolving device as claimed in claim 1, wherein the inner shell is provided with an auxiliary heating element and / or a stirrer, the auxiliary heating element and / or a stirrer being disposed inside the inner shell from top to bottom.

8. The salt-dissolving apparatus of claim 1, wherein the peripheral wall of the inner shell is made of a metallic material so that the liquid molten salt within the inner shell conducts heat to the jacketed salt cavity.

9. The salt dissolving apparatus as claimed in claim 1, wherein the bottom center of the outer casing is provided with a vent for discharging solid molten salt.

10. The salt-dissolving apparatus of claim 1, wherein the heating element is further disposed on the outer bottom wall of the outer housing to heat the bottom salt chamber.

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