Molten salt heat storage device suitable for double-tank molten salt heat storage system

Abstract

The invention discloses a fused salt heat storage device suitable for a double-tank fused salt heat storage system, which comprises a storage tank body, a storage tank base, a monitoring system, a heat dissipation system, a salt inlet and outlet pipeline system and an electric heating system, and is characterized in that the storage tank body 1 is arranged on the storage tank base 2, and the monitoring system comprises a host and a temperature measurement optical fiber; the temperature measuring optical fibers are distributed on the side wall of the storage tank body and in the storage tank base at the bottom of the storage tank body, the host is connected with the temperature measuring optical fibers, the heat dissipation system is arranged in the storage tank base at the bottom of the storage tank body, the salt inlet and outlet pipeline system is arranged on the storage tank body, and the electric heating system is arranged on the side wall of the storage tank body. According to the fused salt heat storage device, a safe and stable storage environment is provided through optimization design of the storage tank body and the storage tank base, leakage detection is achieved by measuring temperature changes of the tank wall and the tank bottom in real time through the temperature measuring optical fibers by means of the distributed optical fiber sensing technology, and an important guarantee is provided for long-term stable operation of a double-tank fused salt heat storage system.

Description

TECHNICAL FIELD

[0001] The application relates to a molten salt heat storage device suitable for a double-tank molten salt heat storage system and belongs to the technical field of heat storage for photothermal power generation. BACKGROUND

[0002] In a molten salt heat storage system of a photothermal power station, a heat collection system, a heat storage system, a steam heat exchange system and a power generation system are usually included. For a molten salt heat storage system of a photothermal power station using a double-tank system, the operation principle is as follows:

[0003] Salt melting stage: the solid molten salt is converted into liquid by a salt melting device and then is pumped into a low-temperature molten salt tank.

[0004] Heat collection stage: the solar radiation is focused on a heat absorber by a concentrator field, and the molten salt in the heat absorber is heated and the temperature is increased.

[0005] Heat storage stage: the heated molten salt is transported to a high-temperature molten salt tank by a molten salt pump, and the molten salt in the low-temperature molten salt tank is pumped to the heat absorber, forming a cycle.

[0006] Power generation stage: the molten salt in the high-temperature molten salt tank is pumped to a steam heat exchanger, in which the heat energy of the molten salt is transferred to water to generate high-temperature and high-pressure steam. The steam drives a power turbine to rotate, and the turbine drives a generator to generate electric energy. The electric energy generated by the generator is transmitted to a power grid after being stepped up by a substation, and the molten salt is cooled and enters the low-temperature molten salt tank.

[0007] The molten salt storage tank is one of the key components of the molten salt heat storage system, and the durability of the storage tank directly affects the safety and economy of the entire molten salt energy storage system. For a large photothermal power station, the diameter of the salt storage tank is usually 30-50 m, the height is several dozen meters, and the single-tank storage capacity is tens of thousands of tons. Taking the 100 MW tower-type photothermal power station built in Dunhuang as an example, the hot tank has a diameter of 39 m, the cold tank has a diameter of 37.4 m, and the height of both is 15 m. The single-tank molten salt storage capacity is as high as 15,000 tons, the working temperature of the molten salt is 520 DEG C, and the single-tank molten salt storage design temperature reaches 600 DEG C. The temperature of the molten salt initially filled in the molten salt storage tank is generally 300-350 DEG C, and the tank wall and bottom plate of the storage tank in the normal temperature state will bear a huge thermal shock load. Therefore, the high-temperature molten salt storage tank has the characteristics of large structure size, high operating temperature and long-term bearing of cyclic load (liquid static pressure, temperature load), and the stress corrosion caused by the severe temperature difference change during use easily leads to the rupture of the weld of the storage tank. In addition, the strong corrosive effect of the chloride ions, sulfate ions, nitrate ions and carbonate ions in the molten salt on the storage tank also seriously affects the production safety and operating life of the large molten salt storage tank. Due to the large size of the storage tank, there is a temperature difference between different parts of the storage tank during preheating and operation, and the large temperature difference stress between the components of the storage tank body also aggravates the risk of leakage of the molten salt storage tank, and once the leakage occurs, it will cause serious harm to the safety of the power station and the surrounding environment.

[0008] Traditional molten salt storage tank usually adopts single wall, and the high-temperature tank wall and tank top material is generally P347H, TP316L steel, and the low-temperature molten salt storage tank wall and tank top material is generally Q345R. The tank wall outside and the tank top inside are covered with relatively thick alumina-silicate fiber felt and other thermal insulation materials. The thermal insulation material is usually thick, needs additional support and fixation, and is exposed for a long time, so the service life is not long in actual engineering, and needs regular maintenance and replacement.

[0009] Therefore, there is a need for a molten salt storage tank which is safe, has good thermal insulation effect, is convenient to construct, and can monitor the deformation and cracking of the tank wall and bottom plate in time. SUMMARY

[0010] The purpose of the present application is to provide a molten salt heat storage device suitable for a double-tank molten salt heat storage system, in particular a double-wall molten salt heat storage tank and foundation structure suitable for a double-tank molten salt heat storage system, to solve the problems of high leakage risk of traditional single-wall storage tank, frequent maintenance of thermal insulation layer, and low utilization rate of tank bottom molten salt.

[0011] To solve the above technical problems, the present application adopts the following technical solution: a molten salt heat storage device suitable for a double-tank molten salt heat storage system, comprising: a storage tank body for storing molten salt; a storage tank foundation on which the storage tank body is placed; a monitoring system comprising a host computer and temperature measuring optical fibers, the temperature measuring optical fibers being distributed on the side wall of the storage tank body and in the storage tank foundation at the bottom of the storage tank body, and the host computer being connected to the temperature measuring optical fibers to measure the temperature changes of the tank wall and tank bottom in real time and realize leakage detection; a heat dissipation system comprising cooling pipelines arranged in a square pattern in the storage tank foundation at the bottom of the storage tank body to ensure the ventilation and heat dissipation effect; an inlet and outlet salt pipeline system for the input and output of molten salt in the storage tank body; and an electric heating system for heating and insulating the molten salt in the storage tank body.

[0012] The aforementioned molten salt heat storage device suitable for a double-tank molten salt heat storage system, the storage tank body comprises a tank top, a tank wall and a tank bottom, the tank top and the tank bottom are arranged at the upper and lower ends of the tank wall to form a sealed tank body, the tank wall is a double-wall structure comprising an inner tank wall and an outer tank wall, the inner tank wall is made of stainless steel which is resistant to high temperature and corrosion; the outer tank wall is made of carbon steel or composite material to improve corrosion resistance and structural strength, a thermal insulation layer and a monitoring layer are arranged between the inner tank wall and the outer tank wall, and the monitoring layer is arranged between the two thermal insulation layers, temperature measuring optical fibers are distributed in the monitoring layer, the thermal insulation layer is filled with thermal insulation material, and the thermal insulation material is made of a material which is resistant to high temperature, has good hydrophobicity, low thermal conductivity and high corrosion resistance.

[0013] The molten salt heat storage device for the double-tank molten salt heat storage system, the monitoring layer adopts a multi-hole material as a support material to provide support for the temperature measuring optical fiber, and the temperature measuring optical fiber in the monitoring layer is arranged in a spiral shape from bottom to top.

[0014] The molten salt heat storage device for the double-tank molten salt heat storage system, the tank top comprises a tank top plate, the tank top plate adopts an arch-shaped shell and is provided with a support structure on the lower side, the inner side wall of the tank top plate is provided with a heat insulation material layer, the support structure bears the weight of the tank top plate and the heat insulation material layer, and the end portion is supported on the outer tank wall, when the diameter of the storage tank body is greater than 30 m, the support structure adopts a truss structure, when the diameter of the storage tank body is 10-30 m, a single beam structure is adopted, and when the diameter of the storage tank body is less than 10 m, a thick plate can be directly supported on the outer wall as the support structure.

[0015] The molten salt heat storage device for the double-tank molten salt heat storage system, the tank bottom is in a convex letter shape with a high middle and low periphery, so that the molten salt below the dead liquid level in the tank fully participates in the circulation.

[0016] The molten salt heat storage device for the double-tank molten salt heat storage system, the inlet and outlet salt pipeline system comprises an inlet salt pipe and an outlet salt pipe, the inlet salt pipe is vertically arranged and has an end portion extending into the inner cavity of the storage tank body to the bottom and connected with a liquid distribution ring pipe, the liquid distribution ring pipe is uniformly provided with nozzles, high-temperature molten salt is transported into the tank, and the outlet salt pipe is vertically arranged and has an end portion extending into the inner cavity of the storage tank body to the bottom recessed area of the tank, in the power generation stage, high-temperature molten salt is pumped by a molten salt pump and transported out of the tank through the outlet salt pipe, so that the bottom molten salt below the dead liquid level fully participates in the circulation.

[0017] The molten salt heat storage device for the double-tank molten salt heat storage system, the storage tank foundation comprises, from bottom to top, a reinforced concrete layer, a heat insulation refractory brick layer, a ceramsite soil layer and a fine sand cushion layer, the heat insulation refractory brick layer is provided with an annular refractory brick on the side, and the ceramsite soil layer and the fine sand cushion layer are arranged inside the annular refractory brick.

[0018] The molten salt heat storage device for the double-tank molten salt heat storage system, the ceramsite soil layer is provided with a temperature measuring optical fiber at the bottom, and the temperature measuring optical fiber is arranged in a coiled shape in the ceramsite soil layer.

[0019] The molten salt heat storage device for the double-tank molten salt heat storage system, the cooling pipeline is arranged in the reinforced concrete layer at the bottom of the storage tank body, and the cooling pipeline is arranged in a square grid shape to ensure the ventilation and heat dissipation effect.

[0020] The aforementioned molten salt heat storage device suitable for a double-tank molten salt heat storage system, the electric heating system comprises electric heaters, a plurality of the electric heaters are installed on the side wall of the storage tank body, the electric heaters are arranged in a radiation uniform manner at the bottom of the side wall of the storage tank body in a jacket extraction mode, and the storage tank body can be preheated before initial charging of the molten salt, or the molten salt can be heated or kept warm to prevent solidification in a low-temperature environment.

[0021] Compared with the prior art, the present application has at least the following beneficial effects:

[0022] (1) The inner tank wall of the present application only bears the molten salt and high-temperature load, and the vertical load of the tank top is borne by the outer tank, thereby reducing the possibility of instability of the inner wall caused by vertical pressure load.

[0023] (2) The temperature measurement structure between the inner wall and the outer wall of the present application can perform real-time temperature monitoring, and once the inner tank leaks, the outer tank can serve as a second line of defense, thereby improving the safety of the tank body.

[0024] (3) The temperature load borne by the outer tank of the present application is smaller than that of the inner tank, the circumferential deformation of the top of the wall is relatively small compared with the single-wall tank of the prior art, the deformation of the support caused by the temperature load of the top support structure is reduced, and thus the reliability of the top support structure is improved.

[0025] (4) The outer tank of the present application can protect the heat preservation and insulation material, thereby improving the service life of the heat preservation and insulation material and reducing the maintenance cost.

[0026] (5) The tank bottom convex structure of the present application helps to improve the effective utilization rate of the molten salt, and reduces the amount and cost of engineering molten salt. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a schematic diagram of the overall structure of the molten salt heat storage device of the present application;

[0028] Figure 2 is a schematic diagram of the tank wall structure of the present application;

[0029] Figure 3 is a schematic diagram of the tank top structure of the present application;

[0030] Figure 4 is a schematic diagram of the foundation structure of the storage tank of the present application;

[0031] Figure 5 is a layout diagram of the temperature measurement optical fiber inside the foundation of the storage tank of the present application;

[0032] Figure 6 is a layout diagram of the heat dissipation system inside the foundation of the storage tank of the present application.

[0033] Fig. 1: 1 - tank body, 101 - tank top, 102 - tank wall, 103 - tank bottom, 104 - inner tank wall, 105 - outer tank wall, 106 - thermal insulation layer, 107 - monitoring layer, 108 - tank top plate, 109 - support structure, 110 - layer of heat insulation material, 2 - tank foundation, 3 - monitoring system, 301 - main machine, 302 - temperature measuring optical fiber, 4 - heat dissipation system, 401 - cooling pipeline, 5 - salt inlet and outlet pipeline system, 501 - salt inlet pipe, 502 - salt outlet pipe, 503 - liquid distribution ring pipe, 6 - electric heating system, 7 - reinforced concrete layer, 8 - layer of heat-insulating refractory bricks, 9 - layer of ceramsite soil, 10 - fine sand cushion, 11 - annular refractory brick.

[0034] The application will be further described below in conjunction with the drawings and specific embodiments. Specific embodiments

[0035] Embodiment 1 of the application: In view of the shortcomings that the traditional molten salt single-wall tank is prone to instability and safety accidents due to leakage, the thermal insulation and heat insulation materials need to be additionally supported and fixed and are regularly maintained and replaced, a double-wall molten salt tank with high safety, good thermal insulation and heat insulation effect, convenient construction and timely operation monitoring of deformation and cracking of the tank wall and bottom plate is proposed. Specifically, a molten salt heat storage device suitable for a double-tank molten salt heat storage system, comprising: a tank body 1, a tank foundation 2, a monitoring system 3, a heat dissipation system 4, a salt inlet and outlet pipeline system 5, and an electric heating system 6, the tank body 1 is used for storing molten salt, the tank body 1 is placed on the tank foundation 2, the monitoring system 3 comprises a main machine 301 and a temperature measuring optical fiber 302, the temperature measuring optical fiber 302 is distributed on the side wall of the tank body 1 and the bottom of the tank body 1 in the tank foundation 2, the temperature measuring optical fiber 302 adopts a metal coated optical fiber with high temperature resistance, chemical corrosion resistance and high mechanical bending capacity, the main machine 301 is connected with the temperature measuring optical fiber 302, the temperature change of the tank wall and the tank bottom is measured in real time through the temperature measuring optical fiber 302, the leakage detection is realized, the heat dissipation system 4 comprises a cooling pipeline 401, the cooling pipeline 401 is arranged in a square shape in the tank foundation 2 at the bottom of the tank body 1 to ensure the ventilation and heat dissipation effect, the salt inlet and outlet pipeline system 5 is arranged on the tank body 1 and is used for input and output of the molten salt in the tank body 1, and the electric heating system 6 is arranged on the side wall of the tank body 1 and is used for heating and thermal insulation of the molten salt in the tank body 1.

[0036] Embodiment 2 of the present application: in view of the defects that the traditional molten salt single-wall storage tank is prone to instability and causes safety accidents when leaking, the thermal insulation material needs to be additionally supported and fixed and needs to be regularly maintained and replaced, a double-wall molten salt storage tank with high safety, good thermal insulation effect, convenient construction and the ability to timely monitor the deformation and cracking of the tank wall and bottom plate is proposed. Specifically, a molten salt heat storage device suitable for a double-tank molten salt heat storage system, comprising: a storage tank body 1, a storage tank foundation 2, a monitoring system 3, a heat dissipation system 4, an in-out salt pipeline system 5, and an electric heating system 6, the storage tank body 1 is used for storing molten salt, the storage tank body 1 is placed on the storage tank foundation 2, the monitoring system 3 comprises a host computer 301 and a temperature measuring optical fiber 302, the temperature measuring optical fiber 302 is distributed on the side wall of the storage tank body 1 and the bottom of the storage tank body 1 in the storage tank foundation 2, the temperature measuring optical fiber 302 adopts a metal coated optical fiber with high temperature resistance, chemical corrosion resistance and high mechanical bending ability, the host computer 301 is connected with the temperature measuring optical fiber 302, the temperature change of the tank wall and the tank bottom is measured in real time through the temperature measuring optical fiber 302, the leakage detection is realized, the heat dissipation system 4 comprises cooling pipelines 401, the cooling pipelines 401 are arranged in a square shape in the storage tank foundation 2 at the bottom of the storage tank body 1, so as to ensure the ventilation and heat dissipation effect, the cooling pipelines 401 can be connected with a blower for air cooling, or cooling liquid can be circulated to realize water cooling, the in-out salt pipeline system 5 is arranged on the storage tank body 1 and is used for input and output of the molten salt in the storage tank body 1, and the electric heating system 6 is arranged on the side wall of the storage tank body 1 and is used for heating and heat preservation of the molten salt in the storage tank body 1.

[0037] The storage tank body 1 in the present application comprises a tank top 101, a tank wall 102 and a tank bottom 103, the tank top 101 and the tank bottom 103 are arranged at the upper and lower ends of the tank wall 102 to form a closed tank body, wherein:

[0038] The tank top 101 comprises a tank top plate 108, the tank top plate 108 adopts an arched shell and is provided with a support structure 109 on the lower side, a heat insulation material layer 110 is arranged on the inner side wall of the tank top plate 108, the support structure 109 bears the weight of the tank top plate 108 and the heat insulation material layer 110, and is supported on the outer tank wall 105 around the end portion, when the diameter of the storage tank body 1 is greater than 30 m, the support structure 109 adopts a truss structure, when the diameter of the storage tank body 1 is 10-30 m, the support structure 109 adopts a single beam structure, and when the diameter of the storage tank body 1 is less than 10 m, a thick plate can be directly used as the support structure and supported on the outer wall;

[0039] The tank wall 102 is a double-wall structure comprising an inner tank wall 104 and an outer tank wall 105, the inner tank wall 104 is made of high-temperature-resistant and corrosion-resistant stainless steel, such as TP347H and TP316L stainless steel, the outer tank wall 105 is made of carbon steel or composite material, such as glass fiber reinforced plastic, to improve corrosion resistance and structural strength, a thermal insulation layer 106 and a monitoring layer 107 are arranged between the inner tank wall 104 and the outer tank wall 105, the monitoring layer 107 is arranged between the two thermal insulation layers 106, temperature measuring optical fibers 302 are distributed in the monitoring layer 107, the monitoring layer 107 is made of multi-hole material as support material, such as expanded perlite or other light fillers, to provide support for the temperature measuring optical fibers 302, the temperature measuring optical fibers 302 in the monitoring layer 107 are arranged in a spiral shape from bottom to top in the monitoring layer 107, and provide a function of monitoring leakage, the thermal insulation layer 106 is filled with thermal insulation material, the thermal insulation material is made of material with high high-temperature resistance, good hydrophobicity, low thermal conductivity and high corrosion resistance, such as mineral wool and aluminum silicate fiber, to reduce heat loss;

[0040] The tank bottom 103 is in a convex structure with high in the middle and low at the four corners, so that the molten salt in the tank below the dead liquid level fully participates in the circulation.

[0041] Embodiment 3 of the present application: in view of the defects that the traditional molten salt single-wall storage tank is prone to instability and safety accidents due to leakage, the thermal insulation material needs additional support and fixing and regular maintenance and replacement, a double-wall molten salt storage tank with high safety, good thermal insulation effect, convenient construction, and timely operation monitoring of deformation and cracking of the tank wall and bottom plate is proposed. Specifically, a molten salt heat storage device suitable for a double-tank molten salt heat storage system, comprising: a storage tank body 1, a storage tank foundation 2, a monitoring system 3, a heat dissipation system 4, an inlet and outlet salt pipeline system 5, and an electric heating system 6, the storage tank body 1 is used for storing molten salt, the storage tank body 1 is placed on the storage tank foundation 2, the monitoring system 3 comprises a host computer 301 and a temperature measuring optical fiber 302, the temperature measuring optical fiber 302 is distributed on the side wall of the storage tank body 1 and the bottom of the storage tank body 1 in the storage tank foundation 2, the temperature measuring optical fiber 302 adopts a metal coated optical fiber with high temperature resistance, chemical corrosion resistance and high mechanical bending capacity, the host computer 301 is connected with the temperature measuring optical fiber 302, the temperature change of the tank wall and the tank bottom is measured in real time through the temperature measuring optical fiber 302, the leakage detection is realized, the heat dissipation system 4 comprises a cooling pipeline 401, the cooling pipeline 401 is arranged in a square shape in the storage tank foundation 2 at the bottom of the storage tank body 1, so as to ensure the ventilation and heat dissipation effect, the inlet and outlet salt pipeline system 5 is arranged on the storage tank body 1, and is used for input and output of the molten salt in the storage tank body 1, the electric heating system 6 is arranged on the side wall of the storage tank body 1 and is used for heating and heat preservation of the molten salt in the storage tank body 1.The tank body 1 comprises a tank top 101, a tank wall 102 and a tank bottom 103, the tank top 101 and the tank bottom 103 are arranged at the upper and lower ends of the tank wall 102 to form a closed tank body, wherein: the tank top 101 comprises a tank top plate 108, the tank top plate 108 adopts an arched shell and is provided with a support structure 109 on the lower side, the inner side wall of the tank top plate 108 is provided with a heat insulation material layer 110, the support structure 109 bears the weight of the tank top plate 108 and the heat insulation material layer 110, and the end portion is supported on the outer tank wall 105, when the diameter of the tank body 1 is greater than 30 m, the support structure 109 adopts a truss structure, when the diameter of the tank body 1 is 10-30 m, a single beam structure is adopted, and when the diameter of the tank body 1 is less than 10 m, a thick plate can be directly supported on the outer wall as the support structure; the tank wall 102 is a double-wall structure comprising an inner tank wall 104 and an outer tank wall 105, the inner tank wall 104 adopts stainless steel with high temperature resistance and corrosion resistance, such as TP347H and TP316L stainless steel, the outer tank wall 105 adopts carbon steel or composite material, such as glass fiber reinforced plastic, to improve corrosion resistance and structural strength, a heat preservation layer 106 and a monitoring layer 107 are arranged between the inner tank wall 104 and the outer tank wall 105, the monitoring layer 107 is arranged between the two heat preservation layers 106, temperature measuring optical fibers 302 are distributed in the monitoring layer 107, the monitoring layer 107 adopts a multi-hole material as a support material, such as expanded perlite or other light fillers, to provide support for the temperature measuring optical fibers 302, the temperature measuring optical fibers 302 in the monitoring layer 107 are arranged in a spiral shape from bottom to top in the monitoring layer 107 and provide a function of monitoring leakage, the heat preservation layer 106 is filled with heat preservation material, and the heat preservation material adopts materials with high temperature resistance, good water repellency, low thermal conductivity and high corrosion resistance, such as mineral wool and aluminum silicate fiber, to reduce heat loss; the tank bottom 103 has a convex structure with a high middle and a low periphery, so that the molten salt below the dead liquid level fully participates in the circulation.

[0042] In the application, the tank foundation 2 comprises a reinforced concrete layer 7, a heat-insulating refractory brick layer 8, a ceramsite soil layer 9 and a fine sand cushion layer 10 from bottom to top, the heat-insulating refractory brick layer 8 is provided with an annular refractory brick 11 on the side, the ceramsite soil layer 9 and the fine sand cushion layer 10 are arranged on the inner side of the annular refractory brick 11, the temperature measuring optical fibers 302 are arranged on the bottom of the ceramsite soil layer 9 in a coiled shape, and the cooling pipes 401 are arranged in a square grid shape in the reinforced concrete layer 7 at the bottom of the tank body 1 to ensure the ventilation and heat dissipation effect.

[0043] Specifically, the in-out salt pipeline system 5 includes an in-salt pipe 501 and an out-salt pipe 502, the in-salt pipe 501 is vertically arranged and has an end portion extending into the inner cavity of the storage tank body 1 to the bottom, and is connected with a liquid distribution ring pipe 503 having nozzles uniformly arranged thereon, so as to transport high-temperature molten salt into the tank, and the out-salt pipe 502 is vertically arranged and has an end portion extending into the inner cavity of the storage tank body 1 to the bottom concave area of the tank bottom 103, in the power generation stage, the high-temperature molten salt is pumped by a molten salt pump and transported out of the tank through the out-salt pipe 502, so that the bottom molten salt below the dead liquid level fully participates in the circulation.

[0044] Specifically, the electric heating system 6 includes electric heaters, a plurality of the electric heaters are installed on the side wall of the storage tank body 1, the electric heaters are jacket pipe extraction type and are arranged in a radiation manner at the bottom of the side wall of the storage tank body 1, so as to preheat the storage tank body 1 before initial charging of the molten salt, or heat or keep warm the molten salt to prevent solidification in a low-temperature environment.

[0045] The working principle of one embodiment of the present application is as follows:

[0046] The present application provides a safe and stable storage environment through the optimized design of the storage tank body 1 and the storage tank foundation 2, the in-out salt pipeline system 5 realizes efficient injection and discharge of the molten salt, the electric heating system 6 maintains the working temperature of the molten salt, and the monitoring system 3 uses the distributed optical fiber sensing technology to realize full coverage and real-time online temperature monitoring of the tank wall 102 and the storage tank foundation 2, accurately grasps the running state of the device, and prevents leakage.

[0047] In the installation and construction process of the present application, the construction sequence of the outer tank wall 105 first and the inner tank wall 104 later is generally adopted, so that the inner tank wall 104 has better construction and welding conditions, the material of the outer tank wall 105 can all use ordinary carbon steel material, the use amount of heat-resistant and corrosion-resistant stainless steel can be significantly reduced, and all the thermal insulation materials of the thermal insulation layer 106 are protected by the outer tank wall 105, so that theoretically the thermal insulation materials and the storage tank have the same service life and are free of maintenance for life, thereby greatly reducing the operation cost and having better thermal insulation performance; on the one hand, heat loss can be reduced and the operation efficiency of the power station can be improved, and on the other hand, the maintenance cost of the wall tank thermal insulation material can be reduced and the durability is better. In addition, the tank bottom convex structure of the present application is beneficial to reducing the engineering molten salt cost.

Claims

1. A molten salt thermal storage device suitable for a dual-tank molten salt thermal storage system, characterized in that, include: The storage tank body (1) is used to store molten salt; The storage tank foundation (2) is placed on the storage tank body (1); The monitoring system (3) consists of a host (301) and a temperature measuring fiber (302). The temperature measuring fiber (302) is distributed in the side wall of the tank body (1) and in the tank foundation (2) at the bottom of the tank body (1). The host (301) is connected to the temperature measuring fiber (302). Heat dissipation system (4), the heat dissipation system (4) includes cooling pipes (401), the cooling pipes (401) are arranged in a grid pattern in the tank foundation (2) at the bottom of the tank body (1); Salt inlet and outlet pipeline system (5) is used for the input and output of molten salt in the storage tank body (1); An electric heating system (6) is used for heating and heat preservation of molten salt inside the tank body (1).

2. A molten salt thermal storage device suitable for a dual-tank molten salt thermal storage system according to claim 1, characterized in that, The tank body (1) includes a tank top (101), a tank wall (102) and a tank bottom (103). The tank top (101) and the tank bottom (103) are located at the upper and lower ends of the tank wall (102) to form a sealed tank. The tank wall (102) is a double-wall structure including an inner tank wall (104) and an outer tank wall (105). An insulation layer (106) and a monitoring layer (107) are provided between the inner tank wall (104) and the outer tank wall (105). The monitoring layer (107) is located between the two insulation layers (106). Temperature measuring optical fibers (302) are distributed in the monitoring layer (107).

3. A molten salt thermal storage device suitable for a dual-tank molten salt thermal storage system according to claim 2, characterized in that, The monitoring layer (107) uses a porous material as the support material, and the temperature measuring optical fiber (302) inside the monitoring layer (107) is arranged in a spiral shape from bottom to top.

4. A molten salt thermal storage device suitable for a dual-tank molten salt thermal storage system according to claim 2, characterized in that, The tank top (101) includes a tank top plate (108), which is an arched shell and has a supporting structure (109) on its lower side. The inner wall of the tank top plate (108) is provided with a heat insulation material layer (110).

5. A molten salt thermal storage device suitable for a dual-tank molten salt thermal storage system according to claim 4, characterized in that, The bottom of the can (103) has a convex shape structure that is high in the middle and low around the edges.

6. A molten salt thermal storage device suitable for a dual-tank molten salt thermal storage system according to claim 5, characterized in that, The salt inlet and outlet pipeline system (5) includes a salt inlet pipe (501) and a salt outlet pipe (502). The salt inlet pipe (501) is vertically arranged and its end extends into the inner cavity of the storage tank body (1) to the bottom and is connected to a liquid distribution ring pipe (503). The liquid distribution ring pipe (503) is uniformly provided with nozzles. The salt outlet pipe (502) is vertically arranged and its end extends into the inner cavity of the storage tank body (1) to the bottom recessed area of ​​the tank bottom (103).

7. A molten salt thermal storage device suitable for a dual-tank molten salt thermal storage system according to claim 1, characterized in that, The tank foundation (2) includes, from bottom to top, a reinforced concrete layer (7), a heat-insulating refractory brick layer (8), a ceramsite layer (9), and a fine sand cushion layer (10). The heat-insulating refractory brick layer (8) is provided with annular refractory bricks (11) on its side. The ceramsite layer (9) and the fine sand cushion layer (10) are placed inside the annular refractory bricks (11).

8. A molten salt thermal storage device suitable for a dual-tank molten salt thermal storage system according to claim 7, characterized in that, A temperature-measuring optical fiber (302) is provided at the bottom of the ceramsite layer (9), and the temperature-measuring optical fiber (302) at the ceramsite layer (9) is arranged in a coiled shape.

9. A molten salt thermal storage device suitable for a dual-tank molten salt thermal storage system according to claim 8, characterized in that, The cooling pipes (401) are located in the reinforced concrete layer (7) at the bottom of the tank body (1), and the cooling pipes (401) are arranged in a grid pattern.

10. A molten salt thermal storage device suitable for a dual-tank molten salt thermal storage system according to claim 1, characterized in that, The electric heating system (6) includes electric heaters, and multiple electric heaters are installed on the side wall of the tank body (1). The electric heaters are of the pull-out type with outer sleeves and are arranged radially and uniformly at the bottom of the side wall of the tank body (1).

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