Phase change energy storage material prepared from ceramsite and preparation method thereof

Abstract

The application discloses a kind of phase change energy storage materials prepared by using ceramsite and a preparation method thereof, the technology is to utilize the heat preservation and multi-hole characteristics of ceramsite, and further increase the pore structure of ceramsite, carry out the negative pressure adsorption of phase change material, and then seal and package the surface, to make the ceramsite with thin wall and large pore as the phase change carrier, the phase change material as the energy storage main body, and the packaging material as the sealing colloid of ceramsite phase change energy storage particle.The ceramsite is sieved before use, and different sizes of ceramsite are subjected to negative pressure acid immersion with different acid concentrations to form larger hollow structure;The phase change material can be paraffin, fatty acid and its derivatives;The phase change energy storage material has a wide range of applications in many fields;By using the state change of phase change material, heat is absorbed or released, so as to control temperature, which can reduce the high temperature of environment, and improve the low temperature of environment, so as to achieve the benefit of "peak shaving and valley filling" of environment temperature.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of phase change energy storage materials, and particularly relates to a phase change energy storage material prepared from ceramsite and a preparation method thereof. BACKGROUND

[0002] Ceramsite is a kind of light aggregate produced by foaming in a rotary kiln. It has a spherical shape, a smooth and hard surface, and a honeycomb structure inside, and has the characteristics of low density, low thermal conductivity and high strength. It is widely used in thermal insulation concrete and structural thermal insulation concrete. After drying, screening and negative pressure low concentration acid leaching, most of the inorganic substances in the interior of the ceramsite are dissolved to form a central storage cavity with thin walls and large pores, so that the original porosity of the ceramsite is further expanded, and the ability to adsorb phase change materials is increased by 4-6 times compared to non-negative pressure acid leaching.

[0003] In recent years, building energy consumption accounts for about one-third of the world's total energy consumption, and more than half of the energy consumption comes from space cooling and heating control. At the same time, under the background of rapid development of building technology, people's requirements for building functions and internal environment comfort are getting higher and higher. To realize rich building functions, the overall energy consumption of the building will inevitably increase, which makes building energy-saving design more and more concerned. Therefore, some energy-saving technologies should be adopted to reduce energy consumption. Simultaneously using phase change materials (PCM-Phase Change Material) in building construction not only can effectively reduce the temperature fluctuation inside the building, but also can reduce energy consumption, which is conducive to improving energy utilization rate and achieving the purpose of energy saving.

[0004] However, the effective combination of PCM and building components is a challenging topic. At present, organic solid-liquid PCM is widely used in building envelopes because of its large latent heat, small volume change, stable performance and other advantages. However, if PCM materials are directly combined with building materials, solid-liquid PCM will easily leak during the phase change process and many irreversible situations will occur. This phenomenon not only greatly affects the thermal efficiency of PCM, but also affects the mechanical properties and durability of building materials; in order to solve the leakage problem, various packaging technologies have been studied, such as microcapsule packaging technology, macroscopic packaging technology and porous material adsorption technology, and therefore we propose a phase change energy storage material prepared from ceramsite and a preparation method thereof to solve the problems existing in the prior art.

[0005] Different from CN1303182C and CN104496544A, the adsorption capacity of the ceramic granules used in the patent increases by 4-6 times after negative pressure acid etching, the phase change energy storage capacity has changed significantly, in addition, the strength and high temperature resistance of the encapsulating material using epoxy resin and active substances will be greatly improved, and the encapsulating capacity is enhanced. Different from CN103509529B, the two encapsulating materials used are different, and furthermore, the strength and high temperature resistance of the phase change material are greatly improved after encapsulation. Different from CN113372097A and CN108373314A, the types of ceramic granules used are different, the ceramic granules used in the patent cover ceramic granules of all materials, including ceramic granules of the above-mentioned materials; furthermore, the patent encapsulates a mixture of epoxy resin, curing agent and active substances, and the strength and high temperature resistance are greatly improved. SUMMARY

[0006] The present application aims to provide a phase change energy storage material prepared from ceramic granules and a preparation method thereof to solve the problems in the prior art mentioned in the background.

[0007] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0008] A phase change energy storage material prepared from ceramic granules, comprising ceramic phase change particles;

[0009] The ceramic phase change particles comprise a phase change carrier, a phase change material and an encapsulating material.

[0010] The phase change carrier is provided as ceramic granules with multiple particle sizes, and the ceramic granules have natural pores and acid-etched channels and central storage cavities formed by acid treatment.

[0011] The phase change material serves as the energy storage body filling the acid-etched channels and the central storage cavities of the ceramic granules.

[0012] The encapsulating material is provided as a mixture of epoxy resin, curing agent and active substances.

[0013] Preferably, the ceramic granules are sieved, subjected to negative pressure acid etching with a low-concentration HF solution, washed, and then dried to obtain ceramic granules with multiple particle sizes.

[0014] The negative pressure acid etching is used to further expand the pores in the ceramic granules to form thin-walled large-pore central storage cavities.

[0015] The phase change material is adsorbed by using the pores and acid-etched channels of the ceramic granules.

[0016] The phase change ceramic granules adsorbing the phase change material are then encapsulated with the encapsulating material to obtain the ceramic phase change particles.

[0017] The application also provides a preparation method of the phase change energy storage material prepared from the ceramsite, comprising the following steps:

[0018] 1) drying and screening the ceramsite to obtain ceramsite with different particle sizes;

[0019] 2) covering the ceramsite with low-concentration hydrofluoric acid and placing the ceramsite in a negative pressure extraction device to extract negative pressure; after the negative pressure extraction, the ceramsite is washed with clean water for 2-5 times and dried for standby;

[0020] 3) heating the phase change material in an oven, and after the phase change material is completely changed into liquid state, the ceramsite in step 2) is poured into the phase change material, so that the liquid level of the phase change material exceeds the ceramsite by 1-5 cm;

[0021] 4) placing the mixture in step 3) in a negative pressure extraction device to extract negative pressure, and after the negative pressure reaches the set value, the gas is extracted for a period of time, then the gas is released, and the negative pressure extraction device is closed;

[0022] 5) cooling the mixture in step 4) to room temperature, and stripping the ceramsite from the solid phase change material;

[0023] 6) preparing a packaging material, weighing epoxy resin, curing agent and active substance, and stirring uniformly; placing the ceramsite in step 5) into the prepared packaging material, mixing the ceramsite and the packaging material uniformly, taking out the ceramsite after the surface of the ceramsite is covered with the packaging material, and rolling the ceramsite on a granulator containing the active substance, so that the surface of the packaging material on the surface of the ceramsite is covered with the active substance and rolled into a circular shape under the action of the granulator; filtering and separating the rolled ceramsite and the active substance, and placing the rolled ceramsite on a deoiling paper and hardening the packaging material;

[0024] 7) preparing the same packaging material as in step 6), and repeating the operation in step 6) for the particles in step 6), and the phase change ceramsite particles are prepared after the particles are hardened.

[0025] Preferably, in step 1), the ceramsite with a particle size of 4.75-13.2 mm is selected, and the phase change material is set as paraffin, fatty acid and its derivatives.

[0026] Preferably, in step 2), the concentration of the hydrofluoric acid covering the ceramsite is 9-15 wt.%, the negative pressure extraction pressure is controlled at 0-3 kPa, and the negative pressure extraction time is 2-4 min.

[0027] Preferably, in step 4), the mixture is placed in the negative pressure extraction device to extract negative pressure, so that the negative pressure reaches 0-3 kPa, and after the negative pressure reaches the set value, the gas is extracted for 2-5 min, then the gas is released, and the negative pressure extraction device is closed.

[0028] Preferably, in step 6), the active substance includes one or more of cement powder, active silicon dioxide particles, fly ash particles and quartz particles.

[0029] Preferably, the epoxy resin, curing agent and active substance are mixed in a mass ratio of 1-5:1:6-9, and the curing agent is the curing agent corresponding to the epoxy resin.

[0030] The technical effects and advantages of the present application: the phase change energy storage material prepared by using ceramsite and the preparation method thereof have the following advantages compared with the prior art:

[0031] 1) The internal porosity of the ceramsite is greatly increased after acid immersion under negative pressure, the adsorption capacity of the phase change material is 2-3 times the mass of the ceramsite itself, and the adsorption capacity is increased by 4-6 times compared with that without acid immersion;

[0032] 2) Ceramsite is common and easy to obtain, and the price is low, which is very suitable as a phase change carrier;

[0033] 3) The strength and sealing property of the ceramsite phase change particles after secondary packaging are high, and they are very suitable to replace common coarse aggregate;

[0034] 4) The ceramsite phase change particles have large phase change enthalpy and good temperature control effect;

[0035] 5) The active substance is added in the packaging material, which increases the high temperature resistance of the packaging material;

[0036] The technology of the present application is to utilize the heat preservation and multi-hole characteristics of ceramsite, further increase the pore structure of ceramsite, adsorb phase change material, and then perform surface sealing and packaging to make ceramsite phase change energy storage particles with porous ceramsite as phase change carrier, phase change material as energy storage main body, and packaging material as sealing colloid. The ceramsite is subjected to acid immersion at a low concentration before use; the phase change material can be paraffin, fatty acid and its derivatives; and the packaging material is a mixture of epoxy resin, curing agent and active substance.

[0037] The phase change energy storage material has wide application in many fields such as aerospace, building, clothing, national defense and military, electric power communication, etc. By utilizing the state change of phase change material, heat is absorbed or released to control temperature, so as to reduce high temperature and increase low temperature, achieving the effect of "peak shaving and valley filling" of environment temperature.

[0038] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. The objects and other advantages of the present application can be achieved and obtained by the structures indicated in the specification and drawings. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 The curve graph of phase change temperature and phase change enthalpy in Example 1 of the present application;

[0040] Figure 2A graph of phase transition temperature and phase transition enthalpy in the present embodiment 2;

[0041] Figure 3 A graph of phase transition temperature and phase transition enthalpy in the present embodiment 3;

[0042] Figure 4 A graph of phase transition temperature and phase transition enthalpy in the present embodiment 4;

[0043] Figure 5 A method flow chart of the preparation method of the phase change energy storage material prepared by using ceramsite. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present application will be clearly and completely described in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The specific embodiments described herein are only used to explain the present application, and are not used to limit the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0045] The present application provides the embodiments as shown in the figure:

[0046] A phase change energy storage material prepared by using ceramsite and a preparation method thereof, comprising the following steps:

[0047] The ceramsite is sieved, acid soaked with a low concentration HF solution, washed, and dried to obtain ceramsite with multiple particle sizes. The pores in the ceramsite are further expanded by negative pressure acid soaking to form a central storage cavity with multiple pores and thin walls. The phase change material is adsorbed by negative pressure through the pores and acid soaking channels of the ceramsite, and the phase change ceramsite with the adsorbed phase change material is encapsulated with an encapsulation material to obtain the ceramsite phase change particles.

[0048] A preparation method of a phase change energy storage material prepared by using ceramsite, comprising the following steps:

[0049] 1) The ceramsite is dried and sieved to obtain ceramsite with different particle sizes.

[0050] 2) The ceramsite is covered with a hydrogen fluoride solution with a concentration of 9-15 wt.%, and is placed in a negative pressure extraction device for negative pressure extraction. After the negative pressure extraction is completed, the ceramsite is washed with clean water for 2-5 times and dried for standby use.

[0051] 3) The phase change material is heated in an oven, and after the phase change material is completely changed into a liquid state, the ceramsite of step 2) is poured into the phase change material, and the liquid level of the phase change material is 1-5 cm higher than the height of the ceramsite.

[0052] 4) Put the mixture of step 3) into a device for negative pressure extraction, and perform negative pressure extraction until the negative pressure reaches 0-3 kPa, and then extract for 2-5 min after reaching the set negative pressure, and then release the air, and close the negative pressure extraction device.

[0053] 5) Cool the mixture of step 4) to room temperature, and separate the ceramsite from the solid phase change material.

[0054] 6) Prepare the encapsulating material, weigh the epoxy resin, curing agent and active substance, and stir them uniformly. Put the ceramsite of step 5) into the prepared encapsulating material, and mix them uniformly. After the surface of the ceramsite is covered with the encapsulating material, take out the ceramsite, and put it into a granulator containing the active substance, and roll it to make the surface of the encapsulating material on the ceramsite covered with the active substance and rolled into a circular shape under the action of the granulator. Filter and separate the rolled ceramsite and the active substance, and place the rolled ceramsite on a deoiling paper, and wait for the encapsulating material to harden.

[0055] 7) Use the same encapsulating material as that of step 6) to perform the operation of step 6) again on the particles of step 6), and after the particles harden, the phase change ceramsite particles are prepared.

[0056] The active substance includes one or more of cement powder, active silicon dioxide particles, fly ash particles and quartz particles.

[0057] The basic principle of the present application is to perform screening treatment on the ceramsite, and under the action of negative pressure acid leaching, the ceramsite will absorb the dilute hydrofluoric acid solution. The dilute hydrofluoric acid solution will react with the materials inside the ceramsite, thereby eroding the inside and further expanding the internal pores of the ceramsite. The phase change material is melted into a liquid state, and the liquid phase change material is absorbed into the inside of the ceramsite by using negative pressure, and then the ceramsite adsorbing the phase change material is encapsulated by using the encapsulating material, and the phase change ceramsite particles are obtained.

[0058] The phase change ceramsite particles are used to absorb or release heat by using the change of the physical state of the phase change material inside the phase change ceramsite particles, so as to achieve the purpose of phase change energy storage of the phase change ceramsite particles. The ceramsite serves as a carrier of the phase change material, and stores the phase change material. The encapsulating material wraps the ceramsite storing the phase change material into a granular shape, and the phase change material will always remain in the encapsulating material when it changes phase, and the encapsulating material can provide a continuous and stable phase change environment for the phase change material. Moreover, the encapsulating material is composed of epoxy resin, curing agent and active substance, which increases the strength and heat resistance of the phase change ceramsite particles.

[0059] Example 1, as shown in Figure 1

[0060] ​After the treatment of step 1), the ceramsite with particle size of 9.5 mm is selected. 10 g of ceramsite is weighed, and 12 wt.% hydrofluoric acid is used for acid immersion. The pressure of negative pressure extraction is 3 kPa, and the extraction time is 4 min. After extraction, rinse 2-5 times with clean water, and dry for standby. The phase change material is 55 degree paraffin, and the oven is used for melting at 90 °C. The encapsulating material uses epoxy resin E51 with a mass of 20 g, curing agent T31 with a mass of 5 g, and active substance cement with a mass of 38 g, which are mixed uniformly and used.

[0061] The phase change enthalpy of this example is △Hm=-133.35 J / g, and the phase change peak temperature Tm=54.45 °C.

[0062] Example 2: As example 1, except as shown in Figure 2 .

[0063] After the treatment of step 1), the ceramsite with particle size of 4.75 mm is selected. 10 g of ceramsite is weighed, and 12 wt.% hydrofluoric acid is used for acid immersion. The pressure of negative pressure extraction is 2 kPa, and the extraction time is 4 min. After extraction, rinse 2-5 times with clean water, and dry for standby. The phase change material is 55 degree paraffin, and the mass required is 500 g. The oven is used for melting at 90 °C. The encapsulating material uses epoxy resin E51 with a mass of 20 g, curing agent T31 with a mass of 5 g, and active substance fly ash particles with a mass of 35 g, which are mixed uniformly and used.

[0064] The phase change enthalpy of this example is △Hm=-116.76 J / g, and the phase change peak temperature Tm=54.62 °C.

[0065] Example 3: As example 1, except as shown in Figure 3 .

[0066] After the treatment of step 1), the ceramsite with particle size of 9.5 mm is selected. 10 g of ceramsite is weighed, and 12 wt.% hydrofluoric acid is used for acid immersion. The pressure of negative pressure extraction is 3 kPa±1 kPa, and the extraction time is 4 min. After extraction, rinse 2-5 times with clean water, and dry for standby. The phase change material is myristic acid, and the oven is used for melting at 90 °C. The encapsulating material uses epoxy resin E51 with a mass of 20 g, curing agent T31 with a mass of 5 g, and active substance active silicon dioxide with a mass of 40 g, which are mixed uniformly and used.

[0067] The phase change enthalpy of this example is △Hm=-138.51 J / g, and the phase change peak temperature Tm=55.45 °C.

[0068] Example 4: As example 1, except as shown in Figure 4 .

[0069] After the treatment of step 1), the ceramsite with a particle size of 4.75 mm is selected. 10 g of the ceramsite is weighed, and acid dipping is carried out using 12 wt.% hydrofluoric acid, the pressure of the negative pressure is 1 kPa, and the gas extraction time is 4 min. After extraction, the ceramsite is washed with clean water for 2-5 times and dried for standby. The phase change material is selected as myristic acid, and the oven is used for melting at a temperature of 90 DEG C. The encapsulating material is epoxy resin E51 with a mass of 20 g, curing agent T31 with a mass of 5 g, and active substance cement with a mass of 36 g, which are mixed uniformly and then used.

[0070] The phase change enthalpy of this example is △Hm=-135.42 J / g, and the phase change peak temperature Tm=55.35 DEG C.

[0071] In summary, the internal porosity of the ceramsite is greatly increased after negative pressure acid dipping, the mass of the adsorbed phase change material is 2-3 times of the mass of the ceramsite itself, and the adsorption capacity is increased by 4-6 times compared with that without acid dipping. The ceramsite is common and easy to obtain, and the price is low, so it is very suitable as a phase change carrier. The strength of the ceramsite phase change particle after secondary encapsulation is high, and the sealing property is good, so it is very suitable to replace common coarse aggregate. The ceramsite phase change particle has large phase change enthalpy and good temperature control effect. The addition of active substance in the encapsulating material increases the high-temperature resistance of the encapsulating material.

[0072] The technology of the present application utilizes the heat preservation and multi-hole characteristics of the ceramsite, further increases the hollow structure of the ceramsite, adsorbs the phase change material, and then performs surface sealing and encapsulation to produce the ceramsite phase change energy storage particle taking the thin-walled large-pore ceramsite as the phase change carrier, the phase change material as the energy storage main body, and the encapsulating material as the sealing colloid. Different sizes of ceramsite are subjected to negative pressure acid dipping with different concentrations of acid to form the phase change ceramsite with high adsorption rate. The phase change material can be paraffin, fatty acid and its derivatives. The encapsulating material is a mixture of epoxy resin, curing agent and active substance. The phase change energy storage material has wide application in many fields such as aerospace, building, clothing, national defense and military, electric power communication, etc. The latent heat is absorbed or released by using the change of the state of the phase change material, so as to control the temperature, reduce the high temperature of the environment, and increase the low temperature of the environment, thereby achieving the benefit of "peak clipping and valley flattening" of the environmental temperature.

[0073] Finally, it should be noted that: the above only describes the preferred embodiments of the present application and is not used to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments or make equivalent replacements to some technical features, as long as they are within the spirit and principles of the present application. Any modification, equivalent replacement, improvement, etc. made shall be included in the protection scope of the present application.

Claims

1. A phase change energy storage material prepared by using ceramsite, characterized in that, The ceramic phase change particle comprises a phase change carrier, a phase change material, and a packaging material. The ceramic phase change particle comprises a phase change carrier, a phase change material, and a packaging material. The phase change carrier is configured as a plurality of ceramic particles with different particle sizes, and the ceramic particles have natural pores and acid-leaching channels and central storage cavities formed by acid treatment. The phase change material is used as an energy storage body for filling the acid-leaching channels and the central storage cavities of the ceramic particles. The packaging material is configured as a mixture of an epoxy resin, a curing agent, and an active substance. The ceramic particles are dried, and sieved to obtain ceramic particles with different particle sizes, including the following steps: the ceramic particles are sieved, subjected to negative pressure acid leaching with low-concentration hydrofluoric acid, and then washed and dried again to obtain ceramic particles with different particle sizes. The acid leaching is used to further expand the pores in the ceramic particles to form central storage cavities with large pores and thin walls. The phase change material is adsorbed in the pores and acid-leaching channels of the ceramic particles by using negative pressure. The phase change ceramic particles adsorbed with the phase change material are packaged with the packaging material to obtain the ceramic phase change particles.

2. The method according to claim 1, wherein the method is characterized by, The method comprises the following steps: 1) After the negative pressure is extracted, the ceramic particles are washed with clean water for 2-5 times, and then dried for standby use; 2) The phase change material is heated in an oven, and after the phase change material is completely changed into a liquid state, the ceramic particles of step 1) are poured into the phase change material, and the liquid level of the phase change material exceeds the ceramic particles by 1-5 cm; 3) The mixture of step 2) is placed in a negative pressure extraction device, and negative pressure is extracted, and after the negative pressure reaches a set value, the gas is extracted for a period of time, and then the gas is released, and the negative pressure extraction device is closed; 4) The mixture of step 3) is cooled to room temperature, and the ceramic particles are separated from the solid phase change material; 5) The packaging material is prepared, and the epoxy resin, the curing agent, and the active substance are weighed and stirred uniformly; the ceramic particles of step 4) are placed in the prepared packaging material, and are uniformly mixed with the packaging material, and after the surface of the ceramic particles is coated with the packaging material, the ceramic particles are taken out and placed on a granulator filled with the active substance to roll, so that the surface of the packaging material on the surface of the ceramic particles is coated with the active substance and rolled into a circular shape under the action of the granulator; the rolled ceramic particles and the active substance are filtered and separated, and the rolled ceramic particles are placed on a deoiling paper and hardened; 6) The same packaging material as in step 5) is prepared, and the particles of step 5) are subjected to the operation of step 5), and after the particles are hardened, the phase change ceramic particle preparation is completed.

3. The method according to claim 2, wherein the method comprises the steps of: mixing the ceramic particles with the phase change material; and heating the mixture to a temperature of 1000°C to 1200°C for 1 to 3 hours. The ceramic particles with different particle sizes are selected from ceramic particles with a particle size of 4.75-13.2 mm, and the phase change material is selected from paraffin, fatty acid, and derivatives thereof.

4. The method according to claim 3, wherein the method comprises the steps of: mixing the ceramic particles with the phase change material; and heating the mixture to a temperature of 1000°C to 1200°C for 1 to 3 hours. The concentration of hydrofluoric acid for covering the ceramic particles is 9-15 wt.%, and the negative pressure extraction pressure is controlled at 0-3 kPa, and the negative pressure extraction time is 2-4 min.

5. The method according to claim 4, wherein the method is characterized by: The epoxy resin, the curing agent, and the active substance are mixed according to a mass ratio of 1-5:1:6-9, and the curing agent is a curing agent corresponding to the epoxy resin.

6. The method according to claim 5, wherein the method comprises the steps of: mixing the ceramic particles with the phase change material; and heating the mixture to a temperature of 1000°C to 1200°C for 1 to 3 hours. In step 3), the mixture is placed in a negative pressure extraction device, and negative pressure is extracted, so that the negative pressure reaches 0-3 kPa, and after the negative pressure reaches a set value, the gas is extracted for 2-5 min, and then the gas is released, and the negative pressure extraction device is closed.

7. The method according to claim 6, wherein the method comprises the steps of: mixing the ceramic particles with the phase change material; and heating the mixture to a temperature of 1000°C to 1200°C for 1 to 3 hours. In step 5), the active substance includes one or more of cement powder, active silicon dioxide particles, and fly ash particles.

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