阅读说明：本技术 一种防泄漏的复合储热材料的制备方法 (Preparation method of leakage-proof composite heat storage material ) 是由 田丽梅 李子源 王养俊 王欢 商震 于 2021-08-11 设计创作，主要内容包括：本发明公开了一种防泄漏的复合储热材料的制备方法,属于储热材料技术领域,针对现有相变储热材料的防泄漏方案所存在缺陷,本发明以聚氨酯海绵为模板依次使用两种不同固含量、粒径与粘度的不同的固含量、粒径与粘度的陶瓷浆料分别浸入内部孔丝和表皮,最后高温烧结并去除模板后,在真空度为-0.1MPa～-0.7MPa环境中吸附熔融的相变储热材料的到所述防泄漏的复合储热材料。复合储热材料的芯材填充率经过100小时,相较于初始状态下降了7％,说明具有良好的防泄漏性能,该材料还具有相变储热密度高的特点。(The invention discloses a preparation method of a leak-proof composite heat storage material, which belongs to the technical field of heat storage materials and aims at overcoming the defects of the leak-proof scheme of the conventional phase-change heat storage material. Compared with the initial state, the filling rate of the core material of the composite heat storage material is reduced by 7% after 100 hours, which shows that the composite heat storage material has good leakage-proof performance and also has the characteristic of high phase-change heat storage density.)

1. A preparation method of a leakage-proof composite heat storage material is characterized by comprising the following steps:

1) firstly, soaking polyurethane sponge with the aperture of 0.8-3mm in NaOH solution with the concentration of 10-25 wt% for 1.5-3 hours;

2) soaking the polyurethane sponge into the ceramic slurry A to enable the slurry to be completely filled in the polyurethane sponge, extruding out the redundant slurry, and standing, drying and shaping for 24 hours to obtain a framework I, wherein the thickness of the slurry attached to the surface of a sponge wire mesh is 0.2-0.5 mm;

3) immersing each surface of the first framework obtained in the step 2) into the ceramic slurry B for 0.5-2mm respectively;

4) placing the shaped polyurethane sponge into a high-temperature furnace, preserving heat for 2 hours at the temperature of 500-;

5) putting the phase-change core material into a container, placing the container in a vacuum high-temperature furnace, heating the container to be molten, immersing the ceramic framework into the core material liquid, and adsorbing the core material liquid for more than 30 minutes in an environment with the vacuum degree of-0.1 MPa to-0.7 MPa until the phase-change core material is completely filled in the internal gap of the ceramic framework;

the ceramic slurry A and the ceramic slurry B have different solid contents, particle sizes and viscosities, the solid content of the ceramic slurry A is larger than that of the ceramic slurry B, the particle size of the ceramic slurry A is larger than that of the ceramic slurry B, and the viscosity of the ceramic slurry A is smaller than that of the ceramic slurry B.

2. The method of preparing a leak resistant composite thermal storage material of claim 1,

the ceramic slurry A comprises the following components: 50-75 wt% of ceramic powder, 1000-3000 mesh particle size, 5-10 wt% of sintering aid, 2-8 wt% of adhesive, 0.5-2 wt% of dispersant and 10-30 wt% of deionized water;

the ceramic slurry B comprises the following components: 45-65 wt% of ceramic powder, 3500-5000 mesh particle size, 5-10 wt% of sintering aid, 4-10 wt% of adhesive, 0.5-2 wt% of dispersant and 10-46 wt% of deionized water.

3. The method of claim 2 wherein ceramic slurry a and ceramic slurry B are selected from one of silicon carbide, aluminum oxide, aluminum nitride and silicon nitride; the sintering aid is alumina and/or kaolin; the adhesive is sodium carboxymethyl cellulose; the dispersant is sodium polyacrylate.

4. The method of claim 1, wherein the phase change core material is a nitrate, nitrite, chloride carbonate, or fluoride salt.

5. The method of claim 4, where the phase change core material is sodium nitrate, potassium nitrate, sodium chloride, potassium chloride, sodium carbonate, and potassium carbonate.

6. A leak-proof composite heat storage material obtained by the method for preparing a leak-proof composite heat storage material according to claim 1.

7. A leak resistant composite heat storage material as in claim 6, wherein said ceramic framework is comprised of internal macropores and surface micropores, the pore size of the internal macropores is 0.8-3mm, the pore size of the surface micropores is 1-20 microns, and the thickness of the microporous layer is 0.5-2 mm.

Technical Field

The invention belongs to the technical field of heat storage materials.

Background

The phase change heat storage material can leak when being heated and melted when being melted, generally, in order to prevent the leakage, firstly, other materials are used for packaging, such as epoxy resin, polyamide resin, metal containers or pipelines, and the defects are that the process is complex, the use temperature is limited, the metal containers are easy to corrode, secondly, the phase change material is compounded with the porous material, the phase change material which is melted on the wall surface flows out under the constraint action of micro-nano-scale gaps, but the method limits the flow of the phase change material, weakens the heat convection intensity, has low porosity and has low heat storage density.

Disclosure of Invention

In order to avoid leakage of the phase-change material in the using process, the invention provides a leakage-proof composite heat storage material and a preparation method thereof.

The leakage-proof composite heat storage material provided by the invention is formed by compounding a ceramic framework and a phase-change core material.

The ceramic skeleton consists of inner macropores and surface micropores, the pore diameter of the inner macropores is 0.8-3mm, the pore diameter of the surface micropores is 1-20 microns, and the thickness of the micropore layer is 0.5-2 mm.

The preparation method of the anti-leakage composite heat storage material comprises the following steps:

1) firstly, soaking polyurethane sponge with the aperture of 0.8-3mm in NaOH solution with the concentration of 10-25 wt% for 1.5-3 hours;

2) and (2) soaking the polyurethane sponge into the ceramic slurry A to enable the slurry to be completely filled in the polyurethane sponge, extruding the redundant slurry out, keeping the thickness of the slurry attached to the surface of the sponge wire mesh to be 0.2-0.5mm, standing, drying for 24 hours, and shaping to obtain the framework I.

3) Immersing each surface of the first framework obtained in the step 2) into the ceramic slurry B for 0.5-2mm respectively.

4) And (3) placing the shaped polyurethane sponge into a high-temperature furnace, preserving heat for 2 hours at the temperature of 500-.

5) Putting the phase-change core material into a container, placing the container in a vacuum high-temperature furnace, heating the container until the phase-change core material is molten, immersing the ceramic framework into the core material liquid, and adsorbing the core material liquid for more than 30 minutes in an environment with the vacuum degree of-0.1 MPa to-0.7 MPa until the internal gap of the ceramic framework is completely filled with the phase-change core material.

Wherein, the ceramic slurry A and the ceramic slurry B have different solid contents, particle sizes and viscosities.

The ceramic slurry A comprises the following components: 50-75 wt% of ceramic powder, 1000-3000 mesh particle size, 5-10 wt% of sintering aid, 2-8 wt% of adhesive, 0.5-2 wt% of dispersant and 10-46 wt% of deionized water.

The ceramic slurry B comprises the following components: 45-65 wt% of ceramic powder, 3500-5000 mesh grain size, 5-10 wt% of sintering aid, 4-10 wt% of adhesive, 0.5-2 wt% of dispersing agent and 10-46 wt% of deionized water

The ceramic slurry A and the ceramic slurry B are selected from one of silicon carbide, aluminum oxide, aluminum nitride and silicon nitride;

the sintering aid is alumina and/or kaolin; the adhesive is sodium carboxymethyl cellulose, and the dispersant is sodium polyacrylate.

The phase change core material includes, but is not limited to, nitrates or nitrites such as sodium nitrate and potassium nitrate, chlorides such as sodium chloride and potassium chloride, carbonates such as sodium carbonate and potassium carbonate, and fluorine salts.

The invention has the beneficial effects that:

the anti-leakage composite heat storage material provided by the invention has the advantages that the inner parts are mutually communicated macropores, the load rate is higher, the heat storage density is high, the heat storage density can reach 237W/m × K under the temperature difference of 200 ℃, the flowing of a core material is not limited, and the core material is not easy to leak when the anti-leakage composite heat storage material is used because the surface layer is microporous. The filling rate of the core material of the composite heat storage material is reduced by 7% compared with the initial state after 100 hours, which shows that the composite heat storage material has good leakage-proof performance.

Drawings

FIG. 1 is a flow chart illustrating the steps of the method of the present invention.

FIG. 2 photograph showing the internal structure of the ceramic skeleton

FIG. 3 photograph of ceramic skeleton

FIG. 4 scanning electron micrograph of epidermis

FIG. 5 is a graph showing the change of filling rate of a composite heat storage material core with time

Detailed Description

Example 1

1) Firstly, the polyurethane sponge with the aperture of 0.8-3mm is pretreated by NaOH.

2) And (2) soaking the polyurethane sponge into the ceramic slurry A to enable the slurry to be completely filled in the polyurethane sponge, extruding the redundant slurry out, keeping the thickness of the slurry attached to the surface of the sponge wire mesh to be 0.2-0.5mm, standing, drying for 24 hours, and shaping to obtain the framework I.

3) Immersing each surface of the first framework obtained in the step 2) into the ceramic slurry B for 0.5-2mm respectively.

4) And (3) placing the shaped foam into a high-temperature furnace, preserving heat for 2 hours at the temperature of 500-.

5) Putting the phase-change core material into a container, placing the container in a vacuum high-temperature furnace, heating the container until the phase-change core material is molten, immersing the ceramic framework into the core material liquid, and adsorbing the core material liquid for more than 30 minutes in an environment with the vacuum degree of-0.1 MPa to-0.7 MPa until the internal gap of the ceramic framework is completely filled with the phase-change core material.

The ceramic slurry A comprises the following components: 60 wt% of silicon carbide powder, 2000-mesh particle size, 6 wt% of each of alumina and kaolin, 1.5 wt% of sodium carboxymethyl cellulose, 0.5 wt% of sodium polyacrylate and 26 wt% of deionized water.

The ceramic slurry B comprises the following components: 56 wt% of silicon carbide powder, 50% of each particle size of 3000 meshes and 5000 meshes, 8 wt% of alumina, 6 wt% of kaolin, 5 wt% of sodium carboxymethyl cellulose, 0.5 wt% of sodium polyacrylate and 24.5 wt% of deionized water.

Because the gaps of the surface microporous layer are formed by gaps among ceramic powder particles, the larger the particle size is, the larger the gaps are, the adsorption of the phase-change core material in the vacuum adsorption process is facilitated, but the core material is easy to leak when the core material works in a normal pressure environment, otherwise, the smaller the particle size is, the smaller the gaps are, the core material is not easy to leak, but the adsorption of the core material is influenced, and in order to take the adsorption process into consideration and prevent the leakage, the particle sizes of the powder in the ceramic slurry B are respectively 50% of 3000 meshes and 5000 meshes. The reason that the content of the adhesive in the ceramic slurry B is higher than that of the slurry A is to improve the viscosity of the slurry, prevent the slurry from being soaked into a large pore space too much and improve the connection strength between the surface skin and a large pore area.

And (3) performance testing:

the prepared composite heat storage material is tested by taking solar salt (40 wt% potassium nitrate +60 wt% sodium nitrate) as a core material, the heat conductivity is 2.1W/mK higher than that of pure solar salt by 0.59W/mK, and the heat storage density is 237W/mK under the temperature difference of 200 ℃. In order to evaluate the leakage-proof performance of the composite phase change material, the obtained composite phase change material sample is placed in a blast high-temperature box, the temperature is raised to be higher than the melting point, the blast machine is started, hot air flows through the surface of the sample, the weight of the sample is weighed every 1 hour, the filling rate is calculated, and the filling rate is calculated by dividing the weight of the core material by the density of the core material and then dividing the volume of the material. Compared with the initial state, the filling rate of the core material of the composite heat storage material is reduced by 7 percent after 100 hours, which shows that the composite heat storage material has good leakage-proof performance.

The above examples are only preferred embodiments of the present invention, and the process of the present invention can be carried out within the following ranges:

the ceramic slurry A comprises the following components: 50-75 wt% of ceramic powder, 1000-3000 mesh particle size, 5-10 wt% of sintering aid, 2-8 wt% of adhesive, 0.5-2 wt% of dispersant and 10-30 wt% of deionized water.

The ceramic slurry B comprises the following components: 45-65 wt% of ceramic powder, 3500-5000 mesh grain size, 5-10 wt% of sintering aid, 4-10 wt% of adhesive, 0.5-2 wt% of dispersant and 10-33 wt% of deionized water.

The ceramic slurry a and the ceramic slurry B are selected from one of silicon carbide, alumina, aluminum nitride, and silicon nitride.

The phase-change core material comprises, but is not limited to, nitrates or nitrites such as sodium nitrate and potassium nitrate, chlorides such as sodium chloride and potassium chloride, carbonates such as sodium carbonate and potassium carbonate, and fluorine salts.