Fused salt storage tank

Abstract

The utility model provides a fused salt storage tank and a temperature control method thereof, the fused salt storage tank comprises a tank body, the tank body comprises a tank bottom, a tank wall and a tank top, the tank bottom, the tank wall and the tank top define a containing cavity, a center detection pipeline penetrating through the containing cavity is arranged in the containing cavity along the axial direction, and the center detection pipeline is communicated with the containing cavity. A working condition detection device for detecting operation conditions in the containing cavity is arranged on the side wall of the center detection pipeline, the working condition detection device is connected with a centralized control system junction box arranged outside the tank body through a connecting wire and the center detection pipeline, and a plurality of layers of heating pipe supporting frames are arranged on the tank wall from top to bottom; and a heating pipe is arranged on each layer of heating pipe support frame. The storage tank is easy to control the temperature of molten salt and uniform in temperature distribution.

Description

Technical Field

[0001] The utility model belongs to the technical field of molten salt storage, and in particular relates to a molten salt storage tank and a temperature control method thereof. Background Art

[0002] Molten salt (abbreviated as molten salt) generally refers to a molten liquid composed of inorganic salts or their mixtures. Molten salt has a wide range of operating temperatures, and there are corresponding materials at 200~1200℃; it has large heat capacity, good thermal stability, low kinematic viscosity, and good high-temperature fluidity, chemical stability and thermal stability. Therefore, molten salt energy storage can be applied to a variety of scenarios, such as solar thermal power stations, flexible transformation of thermal power plants, industrial waste heat storage, valley power industrial heating, photovoltaic power storage, wind power storage, transportation storage, etc.

[0003] Molten salt energy storage generally uses a double-tank heat storage system, with a hot tank temperature of 565°C and a cold tank temperature of 290°C. Binary salt (60% sodium nitrate and 40% potassium nitrate) is usually used as the molten salt material for energy storage, but below 220°C, the molten salt will produce large-scale condensation, so real-time monitoring and heating protection devices are required in the storage tank.

[0004] On the other hand, for the energy storage of thermal power, photovoltaic, and wind power plants, the molten salt is mainly heated by electric heating through the surplus electric energy. The commonly used method is to set an electric heater at the bottom of the storage tank and heat the molten salt through the electric heating tube; however, when the electric heating tube is set at the bottom, the heating efficiency of the bottom molten salt close to the electric heater is high, while the molten salt at the top only relies on internal heat conduction to absorb heat, which is very inefficient, resulting in serious uneven heating of the molten salt in the storage tank. When the temperature distribution of the molten salt at the top and the bottom is uneven, it is necessary to rely on the molten salt pump and the internal pipeline for forced circulation to achieve the purpose of uniform temperature of the molten salt inside the tank. The multiple molten salt pumps and internal pipelines increase the design cost and structural complexity.

[0005] Moreover, the detection probes of existing storage tank designs are mainly distributed around the tank body and are relatively dispersed, which increases the cost of installation and maintenance. A large number of distributed monitoring pipes require a large number of holes to be opened around the tank body, which weakens the strength of the tank body and increases the risk of leakage.

[0006] The existing design of storage tank body mainly uses S34709 material. The preparation cost of this material is high, and domestic steel mills are slowly exploring the solution of rolling with controllable grain size, which leads to high cost of the tank body. Utility Model Content

[0007] The utility model aims to provide a molten salt storage tank, by using which the temperature of the molten salt can be controlled and the temperature distribution is uniform.

[0008] The utility model also aims to provide a temperature control method for a molten salt storage tank.

[0009] To achieve the above-mentioned purpose, the utility model provides a molten salt storage tank, including a tank body, wherein the tank body includes a tank bottom, a tank wall and a tank top, wherein the tank bottom, the tank wall and the tank top enclose a accommodating cavity, wherein a central detection pipe penetrating the accommodating cavity is provided in the axial direction of the accommodating cavity, and a working condition detection device for detecting the operating conditions in the accommodating cavity is provided on the side wall of the central detection pipe, wherein the working condition detection device is connected to a centralized control system junction box disposed outside the tank body via a connecting line and the central detection pipe, and a plurality of layers of heating tube support frames are provided on the tank wall from top to bottom, and a heating tube is provided on each layer of the heating tube support frame.

[0010] In the molten salt storage tank described in the utility model, the heating tube is a serpentine heating tube.

[0011] In the molten salt storage tank described in the utility model, the central detection pipe is filled with heat insulating material.

[0012] In the molten salt storage tank described in the utility model, a plurality of groups of working condition detection devices are arranged on the side wall of the central detection pipe from top to bottom, and each layer of heating pipes corresponds to at least one group of working condition detection devices.

[0013] In the molten salt storage tank described in the utility model, a ladder is provided on the outer wall of the central detection pipe.

[0014] The molten salt storage tank described in the utility model comprises, from the inside to the outside, a heat-resistant non-metal casting insulation layer, a refractory brick layer, a flexible filling layer and a carbon steel outer shell.

[0015] The molten salt storage tank described in the utility model has a reinforcement ring disposed on the outer side of the tank wall.

[0016] In the molten salt storage tank described in the utility model, a minimum liquid level detection point and a maximum liquid level detection point are arranged on the central detection pipeline.

[0017] In the molten salt storage tank described in the utility model, the heating pipe is interlockedly controlled with the working condition detection device.

[0018] To achieve the above-mentioned purpose, the utility model also provides a temperature control method for the molten salt storage tank, heating each layer of heating tubes to keep the molten salt at a preset temperature, and using a working condition detection device to detect the temperature of the molten salt at different heights in real time. When the detected temperature is lower than the expected temperature, the heating tube closest to the detected temperature is heated until the expected temperature is reached.

[0019] Beneficial effects of the utility model:

[0020] The molten salt storage tank of the utility model ensures the completeness and convenient operation of the molten salt storage tank. The manufacturing cost of the storage tank is low, and the multi-layer heating tube improves the heating efficiency and reduces the thermal stress distribution of the tank wall of the molten salt storage tank; using the storage tank, through the centrally controlled heating mode, it is ensured that the molten salt inside the molten salt storage tank is heated evenly during the process of liquid level changes, effectively avoiding local overheating or low temperature, and ensuring the long-term stable operation of the storage tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the structure of the molten salt storage tank of the utility model;

[0022] Figure 2 for Figure 1 A partial enlarged view of middle A;

[0023] Figure 3 It is a structural schematic diagram of a serpentine heating tube;

[0024] Figure 4 A schematic cross-sectional view of the heating tube.

[0025] Wherein, the reference numerals are:

[0026] 1. Centralized control system junction box; 2. Central detection pipeline; 3. Ladder; 4. Heating pipe; 5. Tank wall; 6. Reinforcement ring; 7. Cast insulation layer; 8. Refractory brick layer; 9. Flexible filling layer; 10. Carbon steel shell; 11. Heating pipe support frame; 12. Heating body; 13. Insulation filling material; 14. Heating pipe shell. DETAILED DESCRIPTION

[0027] The present invention is described in detail below through examples. It is necessary to point out that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Those skilled in the art in this field can make some non-essential improvements and adjustments to the present invention based on the above content of the present invention.

[0028] like Figure 1 As shown, a molten salt storage tank includes a tank body, wherein the tank body includes a tank bottom, a tank wall 5 and a tank top, wherein the tank bottom, the tank wall 5 and the tank top enclose a accommodating cavity, wherein a central detection pipe 2 penetrating the accommodating cavity is provided in the axial direction thereof, and a working condition detection device for detecting the operating conditions in the accommodating cavity, such as a pressure detector, a temperature detector, a liquid level detector, etc., is provided on the side wall of the central detection pipe 2. The central detection pipe 2 uses high temperature resistant and corrosion resistant materials, and various working condition detection devices can be integrated into the same pipeline inside. The working condition detection device is connected to a junction box of a centralized control system 1 disposed outside the tank body through a connecting line and the central detection pipe 2. A plurality of layers of heating tube support frames 11 are provided on the tank wall from top to bottom, and a heating tube 4 is provided on each layer of the heating tube support frame 1.

[0029] The molten salt storage tank described in the utility model, the heating tube 4 is a serpentine heating tube, the heating tube 4 is arranged in a serpentine shape and evenly distributed on the same horizontal plane to ensure uniform heating of the same layer. Figure 3 As shown, the serpentine heating pipe includes a straight pipe section and a 180° elbow, the straight pipe section and the 180° elbow are detachably connected through a flange, and the 180° elbow of the serpentine heating pipe is fixed on the heating pipe support frame. The structure of the heating pipe 4 is as follows Figure 4 As shown, a carbon-carbon composite material is used as the heating element 12, and non-metallic insulating filling material 13 is uniformly filled around it as insulation. The heating tube shell 14 is made of heat-resistant and corrosion-resistant metal, such as stainless steel.

[0030] In the molten salt storage tank described in the utility model, the central detection pipe 2 is filled with heat insulating material to ensure that various cable connecting lines are not damaged.

[0031] In the molten salt storage tank described in the utility model, a plurality of groups of working condition detection devices are arranged on the side wall of the central detection pipe 2 from top to bottom, and each layer of heating pipes 4 corresponds to at least one group of working condition detection devices.

[0032] The molten salt storage tank described in the utility model is as follows Figure 1 and Figure 3 As shown, a ladder 3 is provided on the outer wall of the central detection pipe 2, which is used for maintenance personnel to enter the tank body to inspect, install and repair various working condition detection devices, such as temperature, pressure, liquid level probes, etc. The material of the ladder 3 needs to be made of high temperature resistant and corrosion resistant metal.

[0033] The molten salt storage tank described in the utility model is as follows Figure 2 As shown, the tank wall 5 includes a heat-resistant non-metal casting insulation layer 7, a refractory brick layer 8, a flexible filling layer 9 and a carbon steel shell 10 from the inside to the outside. In the specific production of the tank wall, the carbon steel shell 10 is placed first, and then the stacked refractory brick layer 8 is made. A certain thickness is reserved between the carbon steel shell 10 and the refractory brick layer 8 to fill the nanoplate flexible filling layer 9, and finally the heat-resistant non-metal casting insulation layer 7 is cast on the inside. The casting insulation layer 7 should be made of dense corrosion-resistant and high-temperature resistant non-metallic materials to ensure that the molten salt does not leak.

[0034] The molten salt storage tank described in the utility model has a reinforcement ring 6 on the outer side of the tank wall. The reinforcement ring 6 can be used to ensure strength, and the reinforcement ring 6 with different thicknesses and different numbers of layers can be set according to the different compressive strengths of the tank body.

[0035] In the molten salt storage tank of the utility model, the heating pipe 4 is interlockedly controlled with the working condition detection device.

[0036] In the molten salt storage tank described in the utility model, a minimum liquid level detection point T1 and a maximum liquid level detection point Tn are arranged on the central detection pipeline.

[0037] When using the molten salt storage tank described in the utility model, the number of layers of heating tubes in the molten salt storage tank is n, namely F1, F2, F3...Fn, and the pressure, temperature, and liquid level monitoring points are set at the center of each layer of heating tubes, and the temperature monitoring points are T2, T3...Tn-1 from top to bottom. When the temperature of the T1 or T2 temperature point is detected to be lowered, the F1 heating tube is started for heating; when the temperature of the T3 temperature point is detected to be lowered, the F2 heating tube is started for heating to heat the molten salt: by analogy, the whole tank of molten salt can be layered and distributed for heating, and the heating can be stopped after the temperature of each layer in the molten salt storage tank reaches the set value.

[0038] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims of the present invention.

Claims

1. A molten salt storage tank, comprising a tank body, characterized in that: The tank body includes a tank bottom, a tank wall and a tank top, and the tank bottom, the tank wall and the tank top enclose a accommodating cavity. A central detection pipe that penetrates the accommodating cavity is provided in the axial direction of the accommodating cavity, and a working condition detection device for detecting the operating conditions in the accommodating cavity is provided on the side wall of the central detection pipe. The working condition detection device is connected to a centralized control system junction box disposed outside the tank body through a connecting line and the central detection pipe. Several layers of heating tube support frames are provided on the tank wall from top to bottom, and a heating tube is provided on each layer of the heating tube support frame.

2. The molten salt storage tank according to claim 1, characterized in that: The heating tube is a serpentine heating tube.

3. The molten salt storage tank according to claim 1, characterized in that: The central detection pipe is filled with heat insulation material.

4. The molten salt storage tank according to claim 1, characterized in that: A plurality of groups of working condition detection devices are arranged on the side wall of the central detection pipe from top to bottom, and each layer of heating pipes corresponds to at least one group of working condition detection devices.

5. The molten salt storage tank according to claim 1, characterized in that: A ladder is arranged on the outer wall of the central detection pipe.

6. The molten salt storage tank according to claim 1, characterized in that: The tank wall comprises, from the inside to the outside, a heat-resistant non-metal casting insulation layer, a refractory brick layer, a flexible filling layer and a carbon steel outer shell.

7. The molten salt storage tank according to claim 1, characterized in that: A reinforcement ring is arranged on the outer side of the tank wall.

8. The molten salt storage tank according to claim 1, characterized in that: The central detection pipeline is provided with a minimum liquid level detection point and a maximum liquid level detection point.

9. The molten salt storage tank according to claim 1, characterized in that: The heating pipe is interlocked with the working condition detection device for control.

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