Composite phase change heat preservation structure for high temperature storage tank

Abstract

This application discloses a composite phase change insulation structure for high-temperature storage tanks. A high-temperature phase change material layer is added between the refractory insulation material layer and the thermal insulation material layer. The composite multi-layer phase change insulation structure, consisting of a refractory layer, a phase change layer, and a thermal insulation layer from the inside out, reduces internal temperature stratification and heat diffusion of high-temperature substances within the storage tank. This improves the uniformity and stability of the temperature distribution of the medium inside the tank, reduces heat loss, and exhibits strong high-temperature thermal stability, effectively blocking the influence of external ambient temperature and maintaining a constant temperature for the stored substances, thus significantly enhancing the insulation effect. Under the same insulation layer thickness, the insulation structure combined with the phase change material exhibits better insulation performance. While significantly improving the high-temperature heat storage capacity of the storage tank, it also helps to reduce and thin the insulation structure, and opens up new avenues for the application of high-temperature phase change materials in the field of storage tank insulation.

Description

Technical Field

[0001] This application relates to a composite phase change insulation structure for high-temperature storage tanks, belonging to the field of insulation technology. Background Technology

[0002] High-temperature storage tanks are containers used to store high-temperature substances, commonly found in fields such as thermal energy storage, chemical processing, and petroleum. On one hand, many substances undergo physical or chemical changes under the influence of external temperatures, affecting their physical properties. On the other hand, ambient temperatures can cause a decrease in the temperature of the high-temperature substances inside the tank and lead to uneven temperature distribution, affecting the effective heat utilization of the substances. Therefore, the insulation structure of high-temperature storage tanks is crucial, especially in maintaining a stable and uniform temperature distribution of the substances inside the tank.

[0003] The existing insulation structure of high-temperature storage tanks mostly involves coating the inner wall of the tank with fire-resistant and heat-insulating materials and building an insulation layer on the outside of the tank. However, this current insulation structure cannot guarantee a uniform temperature distribution of high-temperature substances inside the tank, and it is easy for a large temperature difference to occur between the edge substances and the center substances, i.e., temperature stratification. Summary of the Invention

[0004] To address the problem of uneven distribution of high-temperature materials inside existing high-temperature storage tanks and temperature stratification between materials in the middle and at the edges of the tank, according to one aspect of this application, a composite phase change insulation structure for high-temperature storage tanks is provided, comprising a tank body, wherein the tank body comprises, from the outside to the inside, a heat insulation layer, a phase change layer, and a fire-resistant layer.

[0005] The inner layer of the refractory layer is in direct contact with the high-temperature material stored in the storage tank;

[0006] The phase change layer is independently packaged, and the inner layer of the phase change layer is bonded to the outer layer of the fire-resistant layer.

[0007] Optionally, the refractory layer is made of refractory material;

[0008] The refractory material is selected from inorganic non-metallic materials that are wear-resistant, high-temperature resistant, and corrosion-resistant.

[0009] Depending on their form, refractory materials commonly used include shaped materials such as refractory bricks, refractory fiber facing modules, and refractory fiber blankets, as well as unshaped refractory materials such as refractory spray coatings, ramming mixes, coatings, and refractory mortars. The selection of refractory materials for actual application in composite structures can be determined based on the characteristics of the substances stored in the storage tank and specific requirements, in order to form a refractory layer.

[0010] Optionally, the refractory material has a refractoriness higher than 1580℃ and can withstand corresponding physicochemical changes and mechanical actions;

[0011] It is made from one of the following: bauxite, silica, magnesite, dolomite, mullite, spinel, and silicon carbide.

[0012] Optionally, the phase change layer is made of a high-temperature phase change material with a phase change temperature of not less than 250°C and a latent heat of phase change of 700 kJ / kg.

[0013] Phase change materials are a class of materials that can absorb or release a large amount of energy when a substance undergoes a phase change. High-temperature phase change materials are those with a phase change temperature above 250℃. The selection of high-temperature phase change materials should meet the following characteristics: small density and volume changes during the phase change process, high energy density, non-evaporation at the operating temperature, strong chemical stability, non-flammability and non-explosiveness, and safe use.

[0014] Optionally, the high-temperature phase change material is selected from one of molten salt, metal and alloy, and inorganic salt composite phase change material.

[0015] Optionally, the phase change layer is made by encapsulating the molten high-temperature phase change material into a porous material under vacuum, thereby ensuring the stability of the phase change material and preventing its leakage.

[0016] The material of the insulation layer should be lightweight, porous, and have a low thermal conductivity.

[0017] Optionally, the insulation layer is made of inorganic insulation material, which is fire-retardant, has good fire resistance, is inexpensive, and easy to install. In the composite structure, a suitable insulation material is selected as the thermal insulation layer based on specific details.

[0018] Optionally, the inorganic thermal insulation material is selected from one of rock wool, glass wool, nano-insulation board, and aluminum silicate fiber.

[0019] Optionally, the insulation layer is made of organic insulation material, which is lightweight, easy to process, and highly dense.

[0020] Optionally, the organic thermal insulation material is selected from one of expanded polystyrene board, extruded polystyrene board, and sprayed polyurethane.

[0021] During application, heat transfer inside the storage tank passes through the refractory layer, phase change layer, and insulation layer. After reaching a steady state, the surface temperature of the refractory layer and insulation layer decreases due to heat conduction. In the phase change layer region, the temperature remains constant, which slows down the heat loss of the storage tank and reduces temperature fluctuations.

[0022] The beneficial effects that this application can produce include:

[0023] The composite phase change insulation structure for high-temperature storage tanks provided in this application can reduce the temperature stratification inside the storage tank and the degree of heat diffusion of high-temperature substances, improve the uniformity and stability of the temperature distribution of the medium inside the storage tank, avoid the phenomenon of local excessively high or low temperatures, and affect the heat utilization of high-temperature substances; reduce the temperature stratification inside the storage tank, reduce the heat loss of the storage tank, have strong high-temperature thermal stability, can block the influence of external ambient temperature, keep the stored substances at a constant temperature, and effectively improve the insulation effect.

[0024] Under the same insulation layer thickness, storage tanks utilizing the large latent heat of phase change materials have better insulation performance. While significantly improving the high-temperature heat storage capacity of storage tanks, it also helps to reduce and thin the insulation structure of storage tanks, ensuring the effective storage of high-temperature substances while saving energy, and opening up new ideas for the application of high-temperature phase change materials in the field of storage tank insulation. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the longitudinal cross-sectional structure of the thermal insulation structure provided in one embodiment of this application;

[0026] Figure 2 This is a schematic diagram of the heat transfer process in an insulation structure provided in one embodiment of this application.

[0027] Figure 3 This is a schematic diagram of the temperature change of the composite structure after the thermal insulation structure provided in one embodiment of this application reaches a steady state.

[0028] Figure 4 This is a schematic diagram showing the temperature distribution of high-temperature substances inside a storage tank with a conventional insulation structure used in the control group of this application over time.

[0029] Figure 5 This is a schematic diagram showing the temperature distribution of the high-temperature material inside the storage tank in Embodiment 1 of this application over time.

[0030] List of components and reference numerals:

[0031] 1-High-temperature material; 2-Refractory layer; 3-Phase change layer; 4-Insulation layer. Detailed Implementation

[0032] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0033] like Figure 1 As shown, according to one embodiment of this application, a composite phase change insulation structure for high-temperature storage tanks is provided, including a tank body, wherein the tank body includes, from the outside to the inside, a heat insulation layer 4, a phase change layer 3, and a fire-resistant layer 2.

[0034] The inner layer of the refractory layer 2 is in direct contact with the high-temperature substance 1 stored in the storage tank;

[0035] The phase change layer 3 is independently packaged, and the inner layer of the phase change layer 3 is bonded to the outer layer of the fire-resistant layer 2.

[0036] The refractory layer 2 is made of refractory material;

[0037] The refractory material is selected from inorganic non-metallic materials that are wear-resistant, high-temperature resistant, and corrosion-resistant.

[0038] Depending on their form, refractory materials commonly used include shaped materials such as refractory bricks, refractory fiber facing modules, and refractory fiber blankets, as well as unshaped refractory materials such as refractory spray coatings, ramming mixes, coatings, and refractory mortars. The selection of refractory materials for actual application in composite structures can be determined according to the characteristics of the substances stored in the storage tank and specific requirements, in order to form a refractory layer 2.

[0039] The refractory material has a refractoriness of over 1580℃ and can withstand corresponding physicochemical changes and mechanical actions.

[0040] It is made from one of the following: bauxite, silica, magnesite, dolomite, mullite, spinel, and silicon carbide.

[0041] The phase change layer 3 is made of high-temperature phase change material with a phase change temperature of not less than 250℃ and a latent heat value of 700kJ / kg.

[0042] Phase change materials are a class of materials that can absorb or release a large amount of energy when a substance undergoes a phase change. High-temperature phase change materials are those with a phase change temperature above 250℃. The selection of high-temperature phase change materials should meet the following characteristics: small density and volume changes during the phase change process, high energy density, non-evaporation at the operating temperature, strong chemical stability, non-flammability and non-explosiveness, and safe use.

[0043] The high-temperature phase change material is selected from one of the following: molten salt, metal and alloy, and inorganic salt composite phase change material.

[0044] The phase change layer 3 is made by encapsulating the molten high-temperature phase change material into a porous material under vacuum, thereby ensuring the stability of the phase change material and preventing its leakage.

[0045] The material of the insulation layer 4 should be lightweight, porous, and have a low thermal conductivity.

[0046] The insulation layer 4 is made of inorganic insulation material, which is difficult to burn, has good fire resistance, is inexpensive, and is easy to install. In the composite structure, a suitable insulation material is selected as the insulation layer 4 based on specific details.

[0047] The inorganic thermal insulation material is selected from one of rock wool, glass wool, nano-insulation board, and aluminum silicate fiber.

[0048] The insulation layer 4 is made of organic insulation material, which is lightweight, easy to process, and highly dense.

[0049] The organic thermal insulation material is selected from one of expanded polystyrene board, extruded polystyrene board, and sprayed polyurethane.

[0050] During application, the heat transfer inside the storage tank passes through the refractory layer 2, the phase change layer 3, and the insulation layer 4 respectively. After reaching a steady state, the surface temperature of the refractory layer 2 and the insulation layer 4 decreases due to heat conduction. In the phase change layer 3, the temperature remains unchanged, which slows down the heat loss of the storage tank and reduces temperature fluctuations.

[0051] Specifically, such as Figure 2 As shown, the heat transfer process of the storage tank includes a complex heat transfer process involving three modes: solid heat conduction, natural heat convection, and heat radiation. Heat conduction refers to the heat exchange between two objects in complete contact or between different parts of an object due to a temperature gradient. The composite phase change insulation structure provided in this application is a multi-layer structure, with heat conducted along the direction of high-temperature material 1 → refractory layer 2 → phase change layer 3 → insulation layer 4 inside the storage tank. Heat convection refers to the heat exchange between the surface of a solid and the surrounding fluid due to a temperature gradient. Natural convection heat transfer and radiation heat transfer mainly occur between the outer surface of the storage tank and the atmosphere. Radiation heat transfer accounts for a very small proportion of the heat dissipation of the storage tank and can generally be ignored.

[0052] like Figure 3 As shown, when the heat transfer in the storage tank reaches a steady state, the temperature distribution of each layer in the composite structure reaches equilibrium. The heat of the high-temperature substance 1 inside the storage tank is conducted through the refractory material. Due to the thermal resistance of the refractory material, the temperature decreases after passing through it. In the phase change layer 3, since the phase change material can maintain its own temperature during the phase change process, the temperature in the phase change layer 3 remains constant. In the insulation layer 4, due to heat conduction, heat convection, and heat radiation, the temperature in the insulation material area gradually decreases.

[0053] Example 1

[0054] The storage tank contains high-temperature material 1, with an inner diameter of 20cm and an initial temperature of 1000℃. The refractory layer 2 is 5cm thick, and the phase change material has a density of 1500kg / m³. 3 Specific heat capacity 0.857 kJ / kg·K, thermal conductivity 0.1 W / m·K; Phase change layer 3 is 10 cm thick, the phase change material is molten sodium chloride, phase change temperature 800℃, latent heat of phase change 492 kJ / kg; insulation layer 4 is 5 cm thick, insulation material density 1800 kg / m³ 3 It has a specific heat capacity of 1.05 kJ / kg·K, a thermal conductivity of 0.1 kJ / kg·K, and a total thickness of 20 cm for the composite structure layer.

[0055] A conventional insulation structure of the same thickness without phase change layer 3 and with the same total thermal resistance was used as a control group for the composite phase change structure of this application, such as... Figure 4 The figure shows the temperature distribution of the high-temperature substance 1 region inside the storage tank under a conventional insulation structure over time. After 60 hours, the temperature on the edge side of the high-temperature substance 1 inside the storage tank with a conventional insulation structure is 993.1℃, the temperature on the edge side is 324.6℃, and the temperature difference between the center side and the edge side of the high-temperature substance 1 is 668.5℃.

[0056] According to the parameters of the materials used in Example 1 above, such as Figure 4 and Figure 5 As shown, the temperature stratification in the high-temperature material 1 region inside the storage tank is significantly reduced; after 60 hours, the temperature on the center side of the high-temperature material 1 inside the storage tank using the composite phase change insulation structure is 997.2℃, and the temperature on the edge side is 777.5℃. The temperature difference between the center side and the edge side of the high-temperature material 1 is 219.7℃. Compared with the ordinary insulation structure, the temperature difference of the high-temperature material 1 inside the storage tank is reduced by 448.8℃, and the temperature on the edge side is increased by 452.9℃.

[0057] Example 2

[0058] The storage tank contains high-temperature material 1, with an inner diameter of 20cm and an initial temperature of 1000℃. The refractory layer 2 is 5cm thick, and the phase change material has a density of 1500kg / m³. 3 Specific heat capacity 0.857 kJ / kg·K, thermal conductivity 0.1 W / m·K; Phase change layer 3 is 10 cm thick, the phase change material is inorganic salt sodium hydroxide, phase change temperature 323℃, phase change potential 170 kJ / kg; Insulation layer 4 is 5 cm thick, insulation material density 1800 kg / m³. 3 It has a specific heat capacity of 1.05 kJ / kg·K, a thermal conductivity of 0.1 kJ / kg·K, and a total thickness of 20 cm for the composite structure layer.

[0059] A conventional insulation structure of the same thickness without phase change layer 3 and with the same total thermal resistance was used as a control group for the composite phase change structure of this application. Following the material parameters applied in Example 2 above, after 60 hours, the temperature at the center of the high-temperature substance 1 inside the tank using the composite phase change insulation structure was 996.4℃, and the temperature at the edge was 667.9℃, with a temperature difference of 328.5℃ between the center and edge of the high-temperature substance 1. Compared to the conventional insulation structure, the temperature difference of the high-temperature substance 1 inside the tank decreased by 340℃, and the temperature at the edge increased by 343.3℃.

[0060] In summary, by combining two embodiments using different phase change materials, it can be shown that in practical applications, this application makes the temperature distribution of the high-temperature substance 1 inside the storage tank more uniform. During the heat release of the phase change material, the composite insulation structure can reduce temperature stratification inside the storage tank, ensure that the distribution of the high-temperature substance 1 inside the storage tank is relatively uniform, reduce the temperature transfer and loss of the high-temperature substance 1 inside the storage tank, extend the insulation time, and maintain the constant temperature of the high-temperature substance 1.

[0061] The above description is only a part of the embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and all fall within the scope of the technical solution.

Claims

1. A composite phase change insulation structure for high-temperature storage tanks, characterized in that, The tank includes a heat insulation layer, a phase change layer, and a fire-resistant layer, which are arranged from the outside to the inside. The inner layer of the refractory layer is in direct contact with the high-temperature material stored in the storage tank; The phase change layer is independently packaged, and the inner layer of the phase change layer is bonded to the outer layer of the fire-resistant layer.

2. The composite phase change insulation structure for high-temperature storage tanks according to claim 1, characterized in that, The refractory layer is made of refractory material; The refractory material is selected from inorganic non-metallic materials that are wear-resistant, high-temperature resistant, and corrosion-resistant.

3. The composite phase change insulation structure for high-temperature storage tanks according to claim 2, characterized in that, The refractory material has a refractoriness of over 1580℃; It is made from one of the following: bauxite, silica, magnesite, dolomite, mullite, spinel, and silicon carbide.

4. The composite phase change insulation structure for high-temperature storage tanks according to claim 3, characterized in that, The phase change layer is made of high-temperature phase change material with a phase change temperature of not less than 250℃ and a latent heat value of 700kJ / kg.

5. A composite phase change insulation structure for high-temperature storage tanks according to claim 4, characterized in that, The high-temperature phase change material is selected from one of the following: molten salt, metal and alloy, or inorganic salt composite phase change material.

6. A composite phase change insulation structure for high-temperature storage tanks according to claim 5, characterized in that, The phase change layer is made by encapsulating a molten high-temperature phase change material into a porous material under vacuum.

7. A composite phase change insulation structure for high-temperature storage tanks according to claim 6, characterized in that, The insulation layer is made of inorganic insulation material.

8. A composite phase change insulation structure for high-temperature storage tanks according to claim 7, characterized in that, The inorganic thermal insulation material is selected from one of rock wool, glass wool, nano-insulation board, and aluminum silicate fiber.

9. A composite phase change insulation structure for high-temperature storage tanks according to claim 6, characterized in that, The insulation layer is made of organic insulation material.

10. A composite phase change insulation structure for high-temperature storage tanks according to claim 9, characterized in that, The organic thermal insulation material is selected from one of expanded polystyrene board, extruded polystyrene board, and sprayed polyurethane.

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