Molten salt storage tank with side pipeline

Abstract

The invention relates to the technical field of fused salt energy storage, in particular to a fused salt storage tank with a side pipeline. According to the fused salt storage tank, the pipeline is arranged on the side face of the tank body, and when hot fused salt is injected into the storage tank, effective vortex can be formed at the bottom of the tank body, so that the heating process of cold fused salt in the tank body is accelerated, and more uniform temperature distribution is achieved; and kinetic energy generated during injection of the hot molten salt is utilized, rapid transfer and dispersion of heat are promoted through formation of vortex, and the maximum boundary temperature difference in the tank body is remarkably reduced. Therefore, according to the technical scheme, the heat storage efficiency is improved, thermal stress caused by temperature difference is reduced, the service life of the storage tank can be prolonged, and the risk of fused salt freezing is reduced. Namely, not only are the problems of temperature difference and thermal stress existing in a traditional fused salt storage tank solved, but also the energy storage and extraction process is effectively optimized by improving the flow characteristic of internal fused salt.

Description

Technical Field

[0001] The invention relates to the technical field of molten salt energy storage, and in particular to a molten salt storage tank with side pipes. Background Art

[0002] Molten salt energy storage technology is an advanced thermal energy storage method widely used in solar power generation and other industrial thermal processes. Molten salt storage tanks use molten salt as an energy storage medium, and through its high melting point and excellent thermal stability, it exhibits excellent performance in collecting, storing and transferring high-temperature thermal energy. In solar thermal power plants, this energy storage method can continue to generate electricity when there is insufficient sunlight, greatly improving the flexibility and economy of energy utilization.

[0003] However, existing molten salt storage tank technology faces several technical challenges. One of them is the change in density of the molten salt inside the tank at different temperatures, which leads to severe stratification of the molten salt and the formation of a thermocline layer. This thermocline layer affects the heat exchange efficiency of the molten salt and limits the uniform extraction and storage of thermal energy. In addition, the temperature extremes of the molten salt in the tank cause the tank to be subjected to uneven thermal stress, which may affect the structural integrity and service life of the tank.

[0004] Based on this, there is an urgent need for a molten salt storage tank with side pipes to solve the above technical problems. Summary of the invention

[0005] The present invention provides a molten salt storage tank with side pipes, which not only solves the temperature difference and thermal stress problems existing in traditional molten salt storage tanks, but also effectively optimizes the energy storage and extraction process by improving the flow characteristics of the internal molten salt.

[0006] An embodiment of the present invention provides a molten salt storage tank with a side pipe, comprising:

[0007] A tank body, wherein a first molten salt inlet is arranged at the top, and a first molten salt outlet is arranged at the bottom, wherein a first molten salt cavity for flowing the molten salt is formed in the tank body, and the first molten salt inlet, the first molten salt cavity and the first molten salt outlet are connected;

[0008] A pipeline is arranged on the side of the tank body, a second molten salt inlet is arranged on the top of the pipeline, a second molten salt outlet is arranged on the bottom, a second molten salt cavity for flowing molten salt is formed in the pipeline, the first molten salt cavity and the second molten salt cavity are connected through the second molten salt inlet and the second molten salt outlet, the first molten salt inlet is located above the second molten salt inlet, and the first molten salt outlet is located below the second molten salt outlet;

[0009] When the molten salt storage tank is working, hot molten salt can enter the first molten salt chamber from the first molten salt inlet, and can enter the second molten salt chamber from the first molten salt chamber through the second molten salt inlet, and finally flow out from the second molten salt outlet to mix with the cold molten salt located at the bottom of the tank.

[0010] It can be seen from the above scheme that the molten salt storage tank with side pipes provided by the present invention, by setting a pipe on the side of the tank body, can form an effective vortex at the bottom of the tank body when the hot molten salt is injected into the storage tank, thereby accelerating the heating process of the cold molten salt inside the tank body and achieving a more uniform temperature distribution; and by utilizing the kinetic energy generated when the hot molten salt is injected, the rapid transfer and dispersion of heat is promoted through the formation of vortices, which significantly reduces the maximum boundary temperature difference in the tank body. Therefore, the above technical scheme not only improves the heat storage efficiency, but also reduces the thermal stress caused by the temperature difference, helps to extend the service life of the storage tank, and reduces the risk of molten salt freezing. That is, it not only solves the temperature difference and thermal stress problems existing in traditional molten salt storage tanks, but also effectively optimizes the energy storage and extraction process by improving the flow characteristics of the internal molten salt. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0012] Figure 1 A schematic structural diagram of a molten salt storage tank with side pipes provided in accordance with an embodiment of the present invention;

[0013] Figure 2 A schematic diagram of a temperature field simulation of a molten salt storage tank with side pipes provided in accordance with an embodiment of the present invention;

[0014] Figure 3 A schematic diagram of velocity field simulation of a molten salt storage tank with side pipes provided in accordance with an embodiment of the present invention.

[0015] Reference numerals:

[0016] 1-tank body;

[0017] 11- first molten salt inlet;

[0018] 12-first molten salt outlet;

[0019] 13- first molten salt chamber;

[0020] 2- Pipeline;

[0021] 21- second molten salt inlet;

[0022] 22- second molten salt outlet;

[0023] 23- second molten salt chamber;

[0024] 3- Molten salt pump. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0026] See also Figure 1 One embodiment of the present invention provides a molten salt storage tank with a side pipe, the molten salt storage tank comprises a tank body 1 and a pipe 2, wherein:

[0027] The tank body 1 is provided with a first molten salt inlet 11 at the top and a first molten salt outlet 12 at the bottom. A second molten salt cavity 23 for flowing the molten salt is formed in the tank body 1. The first molten salt inlet 11, the second molten salt cavity 23 and the first molten salt outlet 12 are connected.

[0028] The pipeline 2 is arranged on the side of the tank body 1, the top of the pipeline 2 is provided with a second molten salt inlet 21, and the bottom is provided with a second molten salt outlet 22. A second molten salt cavity for flowing the molten salt is formed in the pipeline 2, the second molten salt cavity 23 and the second molten salt cavity are connected through the second molten salt inlet 21 and the second molten salt outlet 22, the first molten salt inlet 11 is located above the second molten salt inlet 21, and the first molten salt outlet 12 is located below the second molten salt outlet 22;

[0029] When the molten salt storage tank is working, the hot molten salt can enter the second molten salt chamber 23 from the first molten salt inlet 11, and can enter the second molten salt chamber 23 through the second molten salt inlet 21, and finally flow out from the second molten salt outlet 22 to mix with the cold molten salt at the bottom of the tank body 1 (see Figure 2 , red is hot molten salt, blue is cold molten salt).

[0030] In this embodiment, by arranging the pipe 2 on the side of the tank body 1, the hot molten salt can form an effective vortex at the bottom of the tank body 1 when it is injected into the storage tank (see Figure 3, the white ones are eddies), which accelerates the heating process of the cold molten salt inside the tank and achieves a more uniform temperature distribution; and by utilizing the kinetic energy generated when the hot molten salt is injected, the rapid transfer and dispersion of heat is promoted through the formation of eddies, which significantly reduces the maximum boundary temperature difference in the tank. Therefore, the above technical solution not only improves the heat storage efficiency, but also reduces the thermal stress caused by the temperature difference, helps to extend the service life of the storage tank, and reduces the risk of molten salt freezing. That is, it not only solves the temperature difference and thermal stress problems existing in traditional molten salt storage tanks, but also effectively optimizes the energy storage and extraction process by improving the flow characteristics of the internal molten salt.

[0031] It is understandable that the molten salt storage tank provided in the embodiment of the present invention is a single tank structure. By designing a traditional single tank (i.e., arranging a pipe 2 on the side of the tank body 1), the thermal management and structural performance of the molten salt heat storage single tank can be optimized. Specifically, the advantages of this design are:

[0032] 1) Reduce the impact of temperature difference and stress: By introducing a mixed circulation of cold and hot molten salts in the side pipe, the temperature difference between the cold and hot molten salts inside the tank can be significantly reduced, thereby reducing the thermal stress caused by the temperature difference, protecting the tank structure and extending its service life.

[0033] 2) Destroy the thermocline layer: The addition of side pipes increases the dynamics of the molten salt flow, and the eddy effect generated can effectively destroy the thermocline layer in the tank and promote the uniform distribution of the molten salt. This change in flow pattern improves the heat exchange efficiency and makes the thermal energy storage and access more efficient and balanced.

[0034] In summary, the side pipe design of the present invention not only solves the temperature difference and stress problems existing in traditional molten salt storage tanks, but also effectively optimizes the energy storage and extraction process by improving the flow characteristics of the internal molten salt, bringing new possibilities for the application and development of molten salt energy storage technology.

[0035] In one embodiment of the present invention, the structure of the pipeline 2 is arc-shaped, so as to ensure that the resistance of the molten salt flowing through the second molten salt chamber 23 is minimal, thereby reducing the kinetic energy loss of the molten salt.

[0036] In one embodiment of the present invention, the number of the second molten salt inlets 21 is at least two, that is, the hot molten salt can flow out of the first molten salt chamber 13 through at least two pipes 2, so that the flow rate of the hot molten salt entering the pipe 2 can be increased.

[0037] In one embodiment of the present invention, the number of the second molten salt outlets 22 is at least two, that is, the hot molten salt can flow into the first molten salt chamber 13 through at least two pipes 2, so that the flow rate of the hot molten salt mixed with the cold molten salt can be increased, thereby better achieving uniform temperature distribution and reducing the maximum boundary temperature difference in the tank.

[0038] It should be noted that in the molten salt energy storage system, the thermocline layer describes the temperature stratification phenomenon caused by heat convection and heat conduction in the molten salt storage tank, that is, a region of rapidly changing temperature is formed in the storage tank, which has an important impact on the effective storage and extraction of thermal energy. The formation of a thermocline layer in a molten salt storage tank may affect the effective storage and extraction efficiency of thermal energy, because the temperature gradient will cause uneven distribution of thermal energy in the tank.

[0039] The second molten salt outlet 22 is located at the lower part of the tank body 1. If it is too high, some cold molten salt at the bottom cannot be effectively heated. If it is too low, eddy current disturbance cannot be formed well in the tank body 1. The molten salt speed of the second molten salt outlet 22 is too slow to efficiently solve the influence of the thermocline layer and temperature difference. If it is too fast, the pressure difference between the inside and outside of the tank body 1 is large, which can easily damage the tank body. Therefore, it is necessary to focus on optimizing the setting position of the second molten salt outlet 22 and the molten salt flow rate.

[0040] In one embodiment of the present invention, the height difference between the second molten salt outlet 22 and the first molten salt outlet 12 is not less than one tenth of the height of the tank body 1 and not more than one eighth of the height of the tank body 1 .

[0041] In one embodiment of the present invention, the pipeline 2 is provided with a molten salt pump 3 .

[0042] In this embodiment, by optimizing the setting position of the second molten salt outlet 22 and the molten salt flow rate, that is, constraining the height difference between the second molten salt outlet 22 and the first molten salt outlet 12 and setting the molten salt pump 3 in the pipeline 2, it can further ensure that uniform temperature distribution can be achieved and the maximum boundary temperature difference in the tank body can be reduced.

[0043] In one embodiment of the present invention, the flow rate of the molten salt flowing out of the second molten salt outlet 22 is correlated with the radius of the tank body 1, the type of molten salt and the height difference.

[0044] It should be noted that the larger the tank radius, the greater the molten salt flow rate, and the two are in direct proportion; the type of molten salt determines its flow performance, and the better its flow performance, the greater the molten salt flow rate, and the two are in direct proportion; the greater the height difference, the greater the molten salt flow rate, and the two are in direct proportion. Of course. The molten salt flow rate ultimately depends on the molten salt pump 3, and the above three factors are the key parameters that constrain the molten salt flow rate. In other words, the final molten salt flow rate needs to ensure a good eddy effect, which cannot be too fast or too slow.

[0045] The following describes the use of the above molten salt storage tank:

[0046] When in use, the hot molten salt enters the first molten salt cavity 13 downward from the first molten salt inlet 11 at a certain speed, and part of the hot molten salt flows in from the side pipe 2. The molten salt pump 3 applies speed to the molten salt in the pipe 2, so that the molten salt speed in the second molten salt cavity 23 is greater than the molten salt speed in the first molten salt cavity 13. Finally, the hot molten salt in the pipe 2 flows out from the second molten salt outlet 11, and forms an eddy current under the tank body 1, so that the temperature of the cold molten salt rises rapidly, reducing the extreme temperature difference between the cold and hot molten salts in the tank body 1, which can reduce the stress influence on the tank body 1, and the eddy current can effectively destroy the inclined temperature layer in the tank body 1.

[0047] It should be noted that, in the present invention, relational terms such as first and second 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.

[0048] Finally, it should be noted that the above is only a preferred embodiment of the present invention, which is only used to illustrate the technical solution of the present invention, and is not used to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A molten salt storage tank with side pipes, characterized in that: include: A tank body, wherein a first molten salt inlet is arranged at the top, and a first molten salt outlet is arranged at the bottom, wherein a first molten salt cavity for flowing the molten salt is formed in the tank body, and the first molten salt inlet, the first molten salt cavity and the first molten salt outlet are connected; A pipeline is arranged on the side of the tank body, a second molten salt inlet is arranged on the top of the pipeline, a second molten salt outlet is arranged on the bottom, a second molten salt cavity for flowing molten salt is formed in the pipeline, the first molten salt cavity and the second molten salt cavity are connected through the second molten salt inlet and the second molten salt outlet, the first molten salt inlet is located above the second molten salt inlet, and the first molten salt outlet is located below the second molten salt outlet; When the molten salt storage tank is working, hot molten salt can enter the first molten salt chamber from the first molten salt inlet, and can enter the second molten salt chamber from the first molten salt chamber through the second molten salt inlet, and finally flow out from the second molten salt outlet to mix with the cold molten salt located at the bottom of the tank.

2. The molten salt storage tank according to claim 1, characterized in that: The structure of the pipeline is arc-shaped.

3. The molten salt storage tank according to claim 1, characterized in that: The number of the second molten salt inlets is at least two.

4. The molten salt storage tank according to claim 1, characterized in that: The number of the second molten salt outlets is at least two.

5. The molten salt storage tank according to any one of claims 1 to 4, characterized in that: The height difference between the second molten salt outlet and the first molten salt outlet is not less than one tenth of the height of the tank body and not more than one eighth of the height of the tank body.

6. The molten salt storage tank according to claim 5, characterized in that: The pipeline is provided with a molten salt pump.

7. The molten salt storage tank according to claim 6, characterized in that: The flow rate of the molten salt flowing out of the second molten salt outlet is correlated with the radius of the tank, the type of the molten salt and the height difference.

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