A double-layer core-shell structure high-temperature phase change energy storage capsule and its preparation method

Abstract

The present invention provides a high-temperature phase change energy storage capsule with a double-layer core-shell structure and a preparation method thereof. The preparation method includes: ball-milling a high-temperature molten salt to obtain a core material ball-milled material; performing rolling granulation on the core material ball-milled material to obtain core material particles; ball-milling a carbon source material to obtain a carbon source material ball-milled material; putting the core material particles and the carbon source material ball-milled material into a granulator for rolling granulation to obtain a primary coated body; performing heat treatment on the primary coated body to obtain a primary capsule body; ball-milling solid waste to obtain a solid waste ball-milled material; putting the primary capsule body and the solid waste ball-milled material into a granulator for rolling granulation to obtain a double-layer coated body; and performing heat treatment on the double-layer coated body to obtain a high-temperature phase change energy storage capsule with a double-layer core-shell structure. The preparation method of the high-temperature phase change energy storage capsule of the present invention is simple, low in cost, high in coating rate, good in airtightness, large in latent heat of phase change value, and long in cycle service life, and has potential application value in the fields of power load shifting and industrial waste heat recovery.

Description

Technical Field

[0001] The present invention belongs to the fields of resource reuse and energy storage, and particularly relates to a double-layer core-shell structured high-temperature phase change energy storage capsule and a preparation method thereof. Background Art

[0002] As a phase change energy storage material, high-temperature molten salt phase change energy storage materials have phase change temperatures concentrated above 400 degrees Celsius, and have the advantages of being cheap and easily available, having a low vapor pressure, a wide phase change temperature range, a high latent heat of fusion, good thermal conductivity, and a small volume change during melting. However, during their use, solid-liquid phase changes occur, and there are prominent problems such as easy leakage, unstable morphology, and strong corrosiveness to the encapsulation container, which severely restrict their applications. Currently, mainly through methods such as sintering encapsulation, impregnation encapsulation, and encapsulation by encapsulation into capsules, shaped high-temperature molten salt composite phase change energy storage materials are prepared to solve the application problems they have.

[0003] Encapsulating high-temperature molten salt phase change energy storage materials into capsules is to use metals, metal oxides, ceramics, or glass to coat high-temperature molten salt phase change energy storage materials to form a composite material with a core-shell structure. It has the advantages of simple preparation methods, adjustable capsule size and shell layer thickness, large phase change latent heat value, long cycle service life, and a high degree of matching with the phase change energy storage system. It has high development potential and industrial application value, and is mainly prepared by the following three methods: chemical vapor deposition or electroplating process, glass blowing process at high temperature, and limited water sol-gel process. Currently, the preparation methods of the existing encapsulated high-temperature molten salt phase change energy storage materials have problems such as high raw material costs or high preparation costs caused by complex processes and low coating rates.

[0004] Therefore, how to select suitable raw materials, adopt appropriate processes, and realize the reservation of the expansion space of the core material of the encapsulated high-temperature molten salt phase change energy storage materials and the controllable growth of high-performance capsule wall materials in the design of microscale structures is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of the present invention is to use low-cost solid waste as raw materials, construct a double-layer core-shell structure through a rolling granulation technique, effectively coat the high-temperature molten salt phase change energy storage materials, form a porous carbon intermediate layer that can bear the expansion of the core material, and prepare a high-performance double-layer core-shell structured high-temperature phase change energy storage capsule body.

[0006] To achieve the above object, the present invention provides a method for preparing a high-temperature phase change energy storage capsule with a double-layer core-shell structure. The preparation method includes: ball-milling a high-temperature molten salt to obtain a core material ball-milled material, and putting the core material ball-milled material into a granulator for rolling granulation to obtain core material particles; ball-milling a carbon source material to obtain a carbon source material ball-milled material, and putting the core material particles and the carbon source material ball-milled material into a granulator for rolling granulation to obtain a primary coated body; performing heat treatment on the primary coated body to form a porous carbon structure on the periphery of the high-temperature molten salt, realizing the encapsulation of the high-temperature molten salt by the porous carbon, and obtaining a primary capsule body; ball-milling solid waste to obtain a solid waste ball-milled material, and putting the primary capsule body and the solid waste ball-milled material into a granulator for rolling granulation to obtain a double-layer coated body; performing heat treatment on the double-layer coated body to obtain a high-temperature phase change energy storage capsule with a double-layer core-shell structure; wherein, the phase change temperature of the high-temperature phase change energy storage capsule with a double-layer core-shell structure is 400°C - 1000°C, and the particle size is 1 - 10 mm; the mass of the high-temperature molten salt accounts for 40% - 80% of the mass of the phase change energy storage capsule with a double-layer core-shell structure; the mass of the porous carbon accounts for 5% - 10% of the mass of the phase change energy storage capsule with a double-layer core-shell structure; the mass of the solid waste-based ceramic wall material accounts for 10% - 55% of the mass of the phase change energy storage capsule with a double-layer core-shell structure.

[0007] As a further technical solution of the present invention, the high-temperature molten salt at least includes one of the following: chloride, nitrate, carbonate or fluoride; the chloride at least includes one of the following: sodium chloride, potassium chloride or magnesium chloride; the nitrate at least includes one of the following: sodium nitrate or potassium nitrate; the carbonate at least includes one of the following: sodium carbonate or potassium carbonate; the fluoride at least includes one of the following: sodium fluoride or lithium fluoride.

[0008] As a further technical solution of the present invention, the carbon source material at least includes one of the following: corn starch, sweet potato starch or industrial sucrose.

[0009] As a further technical solution of the present invention, the solid waste at least includes one of the following: fly ash, waste catalyst tailings or spodumene ore dressing tailings.

[0010] As a further technical solution of the present invention, the ball milling of the high-temperature molten salt includes: performing dry ball milling on the high-temperature molten salt, with the ball-to-material ratio being 1:1 - 1.2:1 during the ball milling process, the ball milling time being 1 - 4 h, and the core material ball milled material being obtained after ball milling; the putting the core material ball milled material into a granulator for rolling granulation includes: putting the core material ball milled material into a drum-type disc granulator, and performing rolling granulation with water as the binder. The diameter of the drum-type disc granulator is 50 cm and the depth is 20 cm. The rotation speed during the rolling granulation process is 1 - 100 r / min, and the rolling time is 1 - 20 min. After the rolling granulation is completed, core material particles are obtained.

[0011] As a further technical solution of the present invention, the ball milling of the carbon source material includes: performing dry ball milling on the carbon source material, with the ball-to-material ratio being 1:1 - 1.2:1 during the ball milling process, the ball milling time being 1 - 4 h, and the carbon source material ball milled material being obtained after ball milling; the putting the core material particles and the carbon source material ball milled material into a granulator for rolling granulation includes: putting the core material particles and the carbon source material ball milled material into a drum-type disc granulator, and performing rolling granulation with water as the binder. The diameter of the drum-type disc granulator is 50 cm and the depth is 20 cm. The rotation speed during the rolling granulation process is 1 - 100 r / min, and the rolling time is 1 - 20 min. After the rolling granulation is completed, a primary coated body is obtained.

[0012] As a further technical solution of the present invention, the ball milling of the solid waste includes: performing dry ball milling on the solid waste, with the ball-to-material ratio being 1:1 - 1.5:1 during the ball milling process, the ball milling time being 4 - 8 h, using an 8-mesh grid during the ball milling discharging process, and passing the ball milled solid waste through a 100-mesh sieve after the ball milling is completed to obtain the solid waste ball milled material; the putting the primary capsule body and the solid waste ball milled material into a granulator for rolling granulation includes: putting the primary capsule body and the solid waste ball milled material into a drum-type disc granulator, and performing rolling granulation with water as the binder. The diameter of the drum-type disc granulator is 50 cm and the depth is 20 cm. The rotation speed during the rolling granulation process is 1 - 100 r / min, and the rolling time is 1 - 20 min. After the rolling granulation is completed, a double-layer coated body is obtained.

[0013] As a further technical solution of the present invention, the heat treatment of the primary coated body includes: putting the primary coated body into a heat treatment furnace for heat treatment. During the heat treatment process, the temperature is raised from room temperature to 400 °C at a heating rate of 3 - 10 °C / min, held for 20 - 60 min, and then cooled in the furnace for 80 - 120 min to room temperature, so that a porous carbon structure is formed on the periphery of the high-temperature molten salt, realizing the encapsulation of the high-temperature molten salt by the porous carbon, and obtaining a primary capsule body.

[0014] As a further technical solution of the present invention, the heat treatment of the double-layer coating includes: putting the double-layer coating into a heat treatment furnace for heat treatment. During the heat treatment process, the temperature is raised from room temperature to 800-1200°C at a heating rate of 3-10°C / min, held for 30-120 min, and then cooled in the furnace for 80-120 min to room temperature after the firing is completed, so that the solid waste is sintered to form a solid waste-based ceramic wall material, and a double-layer core-shell structure high-temperature phase change energy storage capsule is obtained.

[0015] Based on the same inventive concept, the present invention also provides a double-layer core-shell structure high-temperature phase change energy storage capsule, which is made by the preparation method described in any one of claims 1-9.

[0016] Beneficial effects: The present invention provides a preparation method for a double-layer core-shell structure high-temperature phase change energy storage capsule, which effectively prepares a phase change energy storage capsule with a high-temperature molten salt as the core material, porous carbon as the intermediate layer, and a solid waste-based ceramic as the wall material. By using the porous carbon material as the intermediate layer, a retention space is formed inside the phase change energy storage capsule, which can bear the expansion of the core material and avoid the core material expanding and squeezing the wall material, resulting in damage to the wall material. By using the solid waste-based ceramic as the raw material for the wall material, the comprehensive recycling and reuse of solid waste resources are realized, and the raw material cost is reduced. By using the rolling granulation technology to construct a double-layer core-shell structure, the effective coating of the high-temperature lava phase change energy storage material is realized, and the particle size can be adjusted. The preparation process of the double-layer core-shell structure high-temperature phase change energy storage capsule of the present invention is simple, with low cost and easy to realize industrialization. The obtained double-layer core-shell structure high-temperature phase change energy storage capsule has a high coating rate, adjustable particle size, a wide phase change temperature range, a high phase change enthalpy value, and a long cycle service life, and can be widely used in fields such as power peak shaving and valley filling and process waste heat recovery and utilization. Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present specification or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0018] Figure 1 It is a flow chart of the preparation method of the double-layer core-shell structure high-temperature phase change energy storage capsule in the embodiment of the present invention;

[0019] Figure 2 It is a schematic diagram of the preparation process of the double-layer core-shell structure high-temperature phase change energy storage capsule in the embodiment of the present invention;

[0020] Figure 3 It is a physical picture of the double-layer core-shell structure high-temperature phase change energy storage capsule prepared in the embodiment of the present invention;

[0021] Figure 4 This is the SEM image of the double-layer core-shell structure high-temperature phase change energy storage capsules prepared in the embodiments of the present invention. Detailed implementation manners

[0022] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art belong to the scope of protection of the present invention.

[0023] Meanwhile, throughout the specification, unless otherwise specifically stated, the terms used herein should be understood as having the meanings as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art to which the present invention pertains. In case of any contradiction, this specification shall prevail.

[0024] Unless otherwise specifically stated, various raw materials, reagents, instruments, and equipment used in the present invention can be obtained through market purchases or can be prepared by existing methods.

[0025] Example 1

[0026] In this example, the high-temperature molten salt used as the core material is sodium chloride, the carbon source material for the intermediate layer of porous carbon is corn starch, and the raw material for the solid waste-based ceramic wall material is solid waste fly ash. The main preparation steps are as follows:

[0027] Preparation of core material particles: The weighed sodium chloride is subjected to dry ball milling. During the ball milling process, the ball-to-material ratio is 1:1, and the ball milling time is 4 h. After ball milling, the core material ball milled material is obtained; the core material ball milled material is put into a drum-type disk granulator, and water is used as the binder for rolling granulation. The diameter of the drum-type disk granulator is 50 cm and the depth is 20 cm. During the rolling granulation process, the rotation speed is 100 r / min, and the rolling time is 1 min. After the rolling granulation is completed, core material particles are obtained;

[0028] Preparation of primary coating bodies: The weighed corn starch is subjected to dry ball milling. During the ball milling process, the ball-to-material ratio is 1:1, and the ball milling time is 4 h. After ball milling, the carbon source material ball milled material is obtained; the core material particles and the carbon source material ball milled material are put into a drum-type disk granulator, and water is used as the binder for rolling granulation. The diameter of the drum-type disk granulator is 50 cm and the depth is 20 cm. During the rolling granulation process, the rotation speed is 20 r / min, and the rolling time is 20 min. After the rolling granulation is completed, primary coating bodies are obtained;

[0029] Preparation of primary capsules: The primary coating is placed in a heat treatment furnace for heat treatment. During the heat treatment process, the temperature is raised from room temperature to 400 °C at a heating rate of 3 °C / min, held for 20 min, and then cooled in the furnace for 80 min to room temperature after the firing is completed, so as to form a porous carbon structure on the periphery of the high-temperature molten salt, realizing the encapsulation of the high-temperature molten salt by the porous carbon, and obtaining primary capsules;

[0030] Preparation of double-layer coating: The weighed fly ash is subjected to dry ball milling. During the ball milling process, the ball-to-material ratio is 1:1, the ball milling time is 4 h, an 8-mesh grid is used during the ball milling and discharging process, and after the ball milling is completed, the ball-milled fly ash is passed through a 100-mesh sieve to obtain solid waste ball milling material; The primary capsules and the solid waste ball milling material are put into a drum-type disk granulator and granulated by rolling with water as the binder. The diameter of the drum-type disk granulator is 50 cm and the depth is 20 cm. The rotation speed during the rolling granulation process is 60 r / min, and the rolling time is 20 min. After the rolling granulation is completed, a double-layer coating is obtained;

[0031] High-temperature phase change energy storage capsules with double-layer core-shell structure: The double-layer coating is placed in a heat treatment furnace for heat treatment. During the heat treatment process, the temperature is raised from room temperature to 800 °C at a heating rate of 3 °C / min, held for 30 min, and then cooled in the furnace for 80 min to room temperature after the firing is completed, so that the solid waste is sintered to form a solid waste-based ceramic wall material, and high-temperature phase change energy storage capsules with a double-layer core-shell structure are obtained.

[0032] In this embodiment, the mass of the sodium chloride core material in the obtained high-temperature phase change energy storage capsules with double-layer core-shell structure accounts for 40% of the double-layer core-shell structure phase change energy storage capsules, the mass of the porous carbon intermediate layer accounts for 5% of the double-layer core-shell structure phase change energy storage capsules, the mass of the solid waste-based ceramic wall material accounts for 55% of the double-layer core-shell structure phase change energy storage capsules, the phase change temperature of the double-layer core-shell structure phase change energy storage capsules is 790 °C, and the particle size is 1 mm.

[0033] Example 2

[0034] In this embodiment, the high-temperature molten salt used as the core material is sodium fluoride, the carbon source material for the porous carbon in the intermediate layer is sweet potato starch / industrial sucrose, and the raw materials for the solid waste-based ceramic wall material are solid waste fly ash / waste catalyst tailings. The main preparation steps are as follows:

[0035] Preparation of core material particles: The weighed sodium fluoride is subjected to dry ball milling. During the ball milling process, the ball-to-material ratio is 1.2:1, the ball milling time is 1 h, and the core material ball milling material is obtained after ball milling; The core material ball milling material is put into a drum-type disk granulator and granulated by rolling with water as the binder. The diameter of the drum-type disk granulator is 50 cm and the depth is 20 cm. The rotation speed during the rolling granulation process is 20 r / min, and the rolling time is 10 min. After the rolling granulation is completed, core material particles are obtained;

[0036] Preparation of primary coating: Weigh the sweet potato starch and industrial sucrose and conduct dry ball milling. During the ball milling process, the ball-to-material ratio is 1.2:1, the ball milling time is 1 h, and the ball milled material of the carbon source is obtained after ball milling; put the core particles and the ball milled material of the carbon source into a drum-type disk granulator, and conduct rolling granulation with water as the binder. The diameter of the drum-type disk granulator is 50 cm and the depth is 20 cm. The rotation speed during rolling granulation is 50 r / min, and the rolling time is 10 min. The primary coating is obtained after the rolling granulation ends;

[0037] Preparation of primary capsule: Put the primary coating into a heat treatment furnace for heat treatment. During the heat treatment process, heat up from room temperature to 400 °C at a heating rate of 10 °C / min, keep warm for 60 min, and cool in the furnace for 120 min to room temperature after the firing ends, so as to form a porous carbon structure on the periphery of the high-temperature molten salt, realize the encapsulation of the high-temperature molten salt by the porous carbon, and obtain the primary capsule;

[0038] Preparation of double-layer coating: Weigh the fly ash and waste catalyst tailings and conduct dry ball milling. During the ball milling process, the ball-to-material ratio is 1.5:1, the ball milling time is 8 h, an 8-mesh grid is used during the ball milling and discharging process, and after the ball milling ends, sieve the ball milled fly ash and waste catalyst tailings through a 100-mesh sieve to obtain the solid waste ball milled material; put the primary capsule and the solid waste ball milled material into a drum-type disk granulator, and conduct rolling granulation with water as the binder. The diameter of the drum-type disk granulator is 50 cm and the depth is 20 cm. The rotation speed during rolling granulation is 100 r / min, and the rolling time is 1 min. The double-layer coating is obtained after the rolling granulation ends;

[0039] High-temperature phase change energy storage capsule with double-layer core-shell structure: Put the double-layer coating into a heat treatment furnace for heat treatment. During the heat treatment process, heat up from room temperature to 1200 °C at a heating rate of 10 °C / min, keep warm for 120 min, and cool in the furnace for 120 min to room temperature after the firing ends, so that the solid waste is sintered to form a solid waste-based ceramic wall material, and the high-temperature phase change energy storage capsule with double-layer core-shell structure is obtained.

[0040] In this embodiment, the mass of the sodium chloride core material in the obtained high-temperature phase change energy storage capsule with double-layer core-shell structure accounts for 80% of the double-layer core-shell structure phase change energy storage capsule, the mass of the porous carbon intermediate layer accounts for 10% of the double-layer core-shell structure phase change energy storage capsule, the mass of the solid waste-based ceramic wall material accounts for 10% of the double-layer core-shell structure phase change energy storage capsule, the phase change temperature of the double-layer core-shell structure phase change energy storage capsule is 980 °C, and the particle size is 10 mm.

[0041] Example 3

[0042] In this embodiment, the high-temperature molten salt used as the core material is sodium chloride / potassium chloride, the carbon source material for the intermediate layer of porous carbon is corn starch / sweet potato starch, and the raw material for the solid waste-based ceramic wall material is solid waste spodumene beneficiation tailings / waste catalyst tailings. The main preparation steps are as follows:

[0043] Preparation of core material particles: Dry ball milling is carried out on the weighed sodium chloride and potassium chloride. During the ball milling process, the ball-to-material ratio is 1:1, and the ball milling time is 3 h. After ball milling, the core material ball milled material is obtained; the core material ball milled material is put into a drum-type disk granulator, and rolling granulation is carried out with water as the binder. The diameter of the drum-type disk granulator is 50 cm and the depth is 20 cm. During the rolling granulation process, the rotation speed is 50 r / min, and the rolling time is 5 min. After the rolling granulation is completed, core material particles are obtained;

[0044] Preparation of primary coating: Dry ball milling is carried out on the weighed corn starch and sweet potato starch. During the ball milling process, the ball-to-material ratio is 1.2:1, and the ball milling time is 4 h. After ball milling, the carbon source material ball milled material is obtained; the core material particles and the carbon source material ball milled material are put into a drum-type disk granulator, and rolling granulation is carried out with water as the binder. The diameter of the drum-type disk granulator is 50 cm and the depth is 20 cm. During the rolling granulation process, the rotation speed is 60 r / min, and the rolling time is 10 min. After the rolling granulation is completed, a primary coating is obtained;

[0045] Preparation of primary capsules: The primary coating is put into a heat treatment furnace for heat treatment. During the heat treatment process, the temperature is raised from room temperature to 400 °C at a heating rate of 8 °C / min, held for 30 min, and then cooled in the furnace for 100 min to room temperature after the firing is completed, so that a porous carbon structure is formed on the periphery of the high-temperature molten salt, realizing the encapsulation of the high-temperature molten salt by the porous carbon, and obtaining primary capsules;

[0046] Preparation of double-layer coating: Dry ball milling is carried out on the weighed spodumene beneficiation tailings and waste catalyst tailings. During the ball milling process, the ball-to-material ratio is 1.5:1, and the ball milling time is 8 h. An 8-mesh grid is used during the ball milling and discharging process. After the ball milling is completed, the ball milled spodumene beneficiation tailings and waste catalyst tailings are sieved through a 100-mesh sieve to obtain solid waste ball milled material; the primary capsules and the solid waste ball milled material are put into a drum-type disk granulator, and rolling granulation is carried out with water as the binder. The diameter of the drum-type disk granulator is 50 cm and the depth is 20 cm. During the rolling granulation process, the rotation speed is 50 r / min, and the rolling time is 20 min. After the rolling granulation is completed, a double-layer coating is obtained;

[0047] High-temperature phase change energy storage capsules with a double-layer core-shell structure: Put the double-layer coating into a heat treatment furnace for heat treatment. During the heat treatment process, heat it from room temperature to 1000 °C at a heating rate of 10 °C / min, hold for 60 min, and then cool it in the furnace for 120 min to room temperature after firing, so that the solid waste is sintered to form a solid waste-based ceramic wall material, and high-temperature phase change energy storage capsules with a double-layer core-shell structure are obtained.

[0048] In this embodiment, the mass of the sodium chloride core material in the obtained high-temperature phase change energy storage capsules with a double-layer core-shell structure accounts for 50% of the double-layer core-shell structure phase change energy storage capsules, the mass of the porous carbon intermediate layer accounts for 10% of the double-layer core-shell structure phase change energy storage capsules, the mass of the solid waste-based ceramic wall material accounts for 40% of the double-layer core-shell structure phase change energy storage capsules, the phase change temperature of the double-layer core-shell structure phase change energy storage capsules is 680 °C, and the particle size is 4 mm.

[0049] Example 4

[0050] In this embodiment, the high-temperature molten salt used as the core material is sodium chloride / potassium chloride / magnesium chloride, the carbon source material for the porous carbon intermediate layer is industrial sucrose, and the raw materials for the solid waste-based ceramic wall material are solid waste spodumene ore dressing tailings / waste catalyst tailings. The main preparation steps are as follows:

[0051] Preparation of core material particles: Dry ball mill the weighed sodium chloride, potassium chloride and magnesium chloride. During the ball milling process, the ball-to-material ratio is 1:1.2 and the ball milling time is 4 h. After ball milling, the core material ball milled material is obtained; put the core material ball milled material into a drum-type disk granulator and perform rolling granulation with water as the binder. The diameter of the drum-type disk granulator is 50 cm and the depth is 20 cm. During the rolling granulation process, the rotation speed is 20 r / min and the rolling time is 20 min. After the rolling granulation is completed, core material particles are obtained;

[0052] Preparation of primary coating: Dry ball mill the weighed industrial sucrose. During the ball milling process, the ball-to-material ratio is 1:1.2 and the ball milling time is 2 h. After ball milling, the carbon source material ball milled material is obtained; put the core material particles and the carbon source material ball milled material into a drum-type disk granulator and perform rolling granulation with water as the binder. The diameter of the drum-type disk granulator is 50 cm and the depth is 20 cm. During the rolling granulation process, the rotation speed is 30 r / min and the rolling time is 5 min. After the rolling granulation is completed, a primary coating is obtained;

[0053] Preparation of primary capsules: Put the primary coating into a heat treatment furnace for heat treatment. During the heat treatment process, heat it from room temperature to 400 °C at a heating rate of 8 °C / min, hold for 30 min, and then cool it in the furnace for 120 min to room temperature after firing, so that a porous carbon structure is formed on the periphery of the high-temperature molten salt, realizing the encapsulation of the high-temperature molten salt by the porous carbon, and primary capsules are obtained;

[0054] Preparation of double-layer coating system: The weighed tailings of spodumene beneficiation and waste catalyst tailings are subjected to dry ball milling. During the ball milling process, the ball-to-material ratio is 1.5:1, the ball milling time is 6 h, an 8-mesh grid is used during the discharging process of ball milling. After the ball milling is completed, the ball-milled tailings of spodumene beneficiation and waste catalyst tailings are passed through a 100-mesh sieve to obtain solid waste ball milling materials; the primary capsule bodies and the solid waste ball milling materials are put into a drum-type disk granulator, and water is used as a binder for rolling granulation. The diameter of the drum-type disk granulator is 50 cm and the depth is 20 cm. During the rolling granulation process, the rotation speed is 60 r / min, and the rolling time is 30 min. After the rolling granulation is completed, a double-layer coating system is obtained.

[0055] High-temperature phase change energy storage capsule with double-layer core-shell structure: The double-layer coating system is put into a heat treatment furnace for heat treatment. During the heat treatment process, the temperature is raised from room temperature to 1000 °C at a heating rate of 10 °C / min, held for 60 min, and then cooled in the furnace for 100 min to room temperature after the firing is completed, so that the solid waste is sintered to form a solid waste-based ceramic wall material, and a high-temperature phase change energy storage capsule with a double-layer core-shell structure is obtained.

[0056] In this embodiment, the mass of the sodium chloride core material in the obtained high-temperature phase change energy storage capsule with a double-layer core-shell structure accounts for 62% of the phase change energy storage capsule with a double-layer core-shell structure, the mass of the porous carbon intermediate layer accounts for 8% of the phase change energy storage capsule with a double-layer core-shell structure, the mass of the solid waste-based ceramic wall material accounts for 30% of the phase change energy storage capsule with a double-layer core-shell structure, the phase change temperature of the phase change energy storage capsule with a double-layer core-shell structure is 430 °C, and the particle size is 6 mm.

[0057] Example 5

[0058] In this embodiment, the high-temperature molten salt used as the core material is sodium chloride / potassium chloride / sodium carbonate, the carbon source material for the porous carbon intermediate layer is corn starch / sweet potato starch / industrial sucrose, and the raw material for the solid waste-based ceramic wall material is solid waste tailings of spodumene beneficiation / fly ash. Its main preparation steps are as follows:

[0059] Preparation of core material particles: The weighed sodium chloride, potassium chloride, and sodium carbonate are subjected to dry ball milling. During the ball milling process, the ball-to-material ratio is 1:1, the ball milling time is 4 h, and the core material ball milling materials are obtained after ball milling; the core material ball milling materials are put into a drum-type disk granulator, and water is used as a binder for rolling granulation. The diameter of the drum-type disk granulator is 50 cm and the depth is 20 cm. During the rolling granulation process, the rotation speed is 40 r / min, and the rolling time is 15 min. After the rolling granulation is completed, core material particles are obtained.

[0060] Preparation of primary coating body: Weigh the corn starch, sweet potato starch and industrial sucrose, and perform dry ball milling. During the ball milling process, the ball-to-material ratio is 1:1, and the ball milling time is 3 h. After ball milling, the ball milled material of the carbon source material is obtained; Put the core material particles and the ball milled material of the carbon source material into a drum-type disc granulator, and perform rolling granulation with water as the binder. The diameter of the drum-type disc granulator is 50 cm and the depth is 20 cm. During the rolling granulation process, the rotation speed is 30 r / min, and the rolling time is 5 min. After the rolling granulation is completed, the primary coating body is obtained;

[0061] Preparation of primary capsule body: Put the primary coating body into a heat treatment furnace for heat treatment. During the heat treatment process, the temperature is raised from room temperature to 400 °C at a heating rate of 10 °C / min, and kept warm for 30 min. After the firing is completed, it is cooled in the furnace for 120 min to room temperature, so that a porous carbon structure is formed on the periphery of the high-temperature molten salt, and the high-temperature molten salt is encapsulated by the porous carbon to obtain the primary capsule body;

[0062] Preparation of double-layer coating body: Weigh the spodumene ore dressing tailings and fly ash, and perform dry ball milling. During the ball milling process, the ball-to-material ratio is 1.5:1, and the ball milling time is 6 h. An 8-mesh grid is used during the ball milling and discharging process. After the ball milling is completed, the ball milled spodumene ore dressing tailings and fly ash are sieved through a 100-mesh sieve to obtain the solid waste ball milled material; Put the primary capsule body and the solid waste ball milled material into a drum-type disc granulator, and perform rolling granulation with water as the binder. The diameter of the drum-type disc granulator is 50 cm and the depth is 20 cm. During the rolling granulation process, the rotation speed is 60 r / min, and the rolling time is 30 min. After the rolling granulation is completed, the double-layer coating body is obtained;

[0063] High-temperature phase change energy storage capsule with double-layer core-shell structure: Put the double-layer coating body into a heat treatment furnace for heat treatment. During the heat treatment process, the temperature is raised from room temperature to 1000 °C at a heating rate of 10 °C / min, and kept warm for 60 min. After the firing is completed, it is cooled in the furnace for 100 min to room temperature, so that the solid waste is sintered to form a solid waste-based ceramic wall material, and the high-temperature phase change energy storage capsule with double-layer core-shell structure is obtained.

[0064] In this embodiment, the mass of the sodium chloride core material of the obtained high-temperature phase change energy storage capsule with double-layer core-shell structure accounts for 70% of the double-layer core-shell structure phase change energy storage capsule, the mass of the porous carbon intermediate layer accounts for 10% of the double-layer core-shell structure phase change energy storage capsule, and the mass of the solid waste-based ceramic wall material accounts for 20% of the double-layer core-shell structure phase change energy storage capsule. The phase change temperature of the double-layer core-shell structure phase change energy storage capsule is 570 °C, and the particle size is 8 mm.

[0065] It can be seen from Examples 1-5 that the preparation method of the double-layer core-shell structure high-temperature phase change energy storage capsule proposed by the present invention effectively prepares a phase change energy storage capsule with a high-temperature molten salt as the core material, porous carbon as the intermediate layer, and solid waste-based ceramics as the wall material. By using porous carbon as the intermediate layer, a retention space is formed inside the phase change energy storage capsule, which can bear the expansion of the core material and prevent the core material from expanding and squeezing the wall material, resulting in wall material damage. By using solid waste-based ceramics as the raw material for the ceramic wall material, the comprehensive recycling and reuse of solid waste resources are realized, and the raw material cost is reduced. By using the rolling granulation technology to construct a double-layer core-shell structure, the effective coating of the high-temperature lava phase change energy storage material is realized, and the particle size can be adjusted. The preparation process of the double-layer core-shell structure high-temperature phase change energy storage capsule of the present invention is simple, low in cost, easy to industrialize, and the obtained double-layer core-shell structure high-temperature phase change energy storage capsule has a high coating rate, adjustable particle size, a wide phase change temperature range, a high phase change enthalpy value, and a long cycle service life, and can be widely used in fields such as power peak shaving and valley filling and process waste heat recovery and utilization.

[0066] The high-temperature molten salt includes at least one of the following: chloride, nitrate, carbonate or fluoride; the chloride includes at least one of the following: sodium chloride, potassium chloride or magnesium chloride; the nitrate includes at least one of the following: sodium nitrate or potassium nitrate; the carbonate includes at least one of the following: sodium carbonate or potassium carbonate; the fluoride includes at least one of the following: sodium fluoride or lithium fluoride; the porous carbon material includes at least one of the following: corn starch, sweet potato starch or industrial sucrose; the solid waste-based ceramics includes at least one of the following: fly ash, waste catalyst tailings or spodumene ore dressing tailings, and the raw materials can be freely combined to prepare a multi-component system core material, so that the use temperature of the prepared double-layer core-shell structure high-temperature phase change energy storage capsule can be adjusted in the range of 400°C - 1000°C, with a wide phase change temperature range and a high phase change enthalpy value.

[0067] Finally, it should also be noted that the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0068] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications once they learn the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0069] Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A preparation method of a high-temperature phase change energy storage capsule with a double-layer core-shell structure, characterized in that, The preparation method includes: Ball-milling the high-temperature molten salt to obtain a core material ball-milled material, and putting the core material ball-milled material into a granulator for rolling granulation to obtain core material particles; Ball-milling the carbon source material to obtain a carbon source material ball-milled material, and putting the core material particles and the carbon source material ball-milled material into a granulator for rolling granulation to obtain a primary coated body; Performing heat treatment on the primary coated body so that a porous carbon structure is formed on the periphery of the high-temperature molten salt, realizing the encapsulation of the high-temperature molten salt by the porous carbon to obtain a primary capsule body; the heat treatment of the primary coated body includes: putting the primary coated body into a heat treatment furnace for heat treatment, and during the heat treatment, heating from room temperature to 400 °C at a heating rate of 3-10 °C / min, holding for 20-60 min, and after the firing is completed, cooling with the furnace for 80-120 min to room temperature, so that a porous carbon structure is formed on the periphery of the high-temperature molten salt, realizing the encapsulation of the high-temperature molten salt by the porous carbon to obtain a primary capsule body; Ball-milling the solid waste to obtain a solid waste ball-milled material, and putting the primary capsule body and the solid waste ball-milled material into a granulator for rolling granulation to obtain a double-layer coated body; Performing heat treatment on the double-layer coated body so that the solid waste is sintered to form a solid waste-based ceramic wall material to obtain a high-temperature phase change energy storage capsule with a double-layer core-shell structure; Wherein, the phase change temperature of the high-temperature phase change energy storage capsule with a double-layer core-shell structure is 400 °C - 1000 °C, and the particle size is 1-10 mm; the mass of the high-temperature molten salt accounts for 40%-80% of the mass of the double-layer core-shell structure phase change energy storage capsule; the mass of the porous carbon accounts for 5%-10% of the mass of the double-layer core-shell structure phase change energy storage capsule; the mass of the solid waste-based ceramic wall material accounts for 10%-55% of the mass of the double-layer core-shell structure phase change energy storage capsule.

2. The preparation method of the high-temperature phase change energy storage capsule with a double-layer core-shell structure according to claim 1, characterized in that: The high-temperature molten salt includes at least one of the following: chloride, nitrate, carbonate or fluoride; The chloride includes at least one of the following: sodium chloride, potassium chloride or magnesium chloride; The nitrate includes at least one of the following: sodium nitrate or potassium nitrate; The carbonate includes at least one of the following: sodium carbonate or potassium carbonate; The fluoride includes at least one of the following: sodium fluoride or lithium fluoride.

3. The preparation method of the high-temperature phase change energy storage capsule with a double-layer core-shell structure according to claim 2, characterized in that: The carbon source material includes at least one of the following: corn starch, sweet potato starch or industrial sucrose.

4. The preparation method of the high-temperature phase change energy storage capsule with a double-layer core-shell structure according to claim 3, characterized in that: The solid waste includes at least one of the following: fly ash, waste catalyst tailings or spodumene beneficiation tailings.

5. The preparation method of the high-temperature phase change energy storage capsule with a double-layer core-shell structure according to claim 4, characterized in that: The ball milling of the high-temperature molten salt includes: performing dry ball milling on the high-temperature molten salt, with the ball-to-material ratio being 1:1 - 1.2:1 during the ball milling process, the ball milling time being 1 - 4 h, and obtaining the core material ball-milled material after ball milling; The putting the core material ball-milled material into a granulator for rolling granulation includes: putting the core material ball-milled material into a drum-type disk granulator, and performing rolling granulation with water as the binder. The diameter of the drum-type disk granulator is 50 cm and the depth is 20 cm. The rotation speed during the rolling granulation process is 1 - 100 r / min, the rolling time is 1 - 20 min, and core material particles are obtained after the rolling granulation ends.

6. The preparation method of the double-layer core-shell structure high-temperature phase change energy storage capsule according to claim 5, characterized in that: The ball milling of the carbon source material includes: performing dry ball milling on the carbon source material, with the ball-to-material ratio being 1:1 - 1.2:1 during the ball milling process, the ball milling time being 1 - 4 h, and obtaining the carbon source material ball-milled material after ball milling; The putting the core material particles and the carbon source material ball-milled material into a granulator for rolling granulation includes: putting the core material particles and the carbon source material ball-milled material into a drum-type disk granulator, and performing rolling granulation with water as the binder. The diameter of the drum-type disk granulator is 50 cm and the depth is 20 cm. The rotation speed during the rolling granulation process is 1 - 100 r / min, the rolling time is 1 - 20 min, and a primary coated body is obtained after the rolling granulation ends.

7. The preparation method of the double-layer core-shell structure high-temperature phase change energy storage capsule according to claim 6, characterized in that: The ball milling of the solid waste includes: performing dry ball milling on the solid waste, with the ball-to-material ratio being 1:1 - 1.5:1 during the ball milling process, the ball milling time being 4 - 8 h, using an 8-mesh grid during the ball milling and discharging process, and passing the ball-milled solid waste through a 100-mesh sieve after ball milling to obtain the solid waste ball-milled material; The putting the primary capsule body and the solid waste ball-milled material into a granulator for rolling granulation includes: putting the primary capsule body and the solid waste ball-milled material into a drum-type disk granulator, and performing rolling granulation with water as the binder. The diameter of the drum-type disk granulator is 50 cm and the depth is 20 cm. The rotation speed during the rolling granulation process is 1 - 100 r / min, the rolling time is 1 - 20 min, and a double-layer coated body is obtained after the rolling granulation ends.

8. The preparation method of the double-layer core-shell structure high-temperature phase change energy storage capsule according to claim 7, characterized in that : The heat treatment of the double-layer coated body includes: putting the double-layer coated body into a heat treatment furnace for heat treatment. During the heat treatment process, the temperature is raised from room temperature to 800 - 1200 °C at a heating rate of 3 - 10 °C / min, held for 30 - 120 min, and then cooled in the furnace for 80 - 120 min to room temperature, so that the solid waste is sintered to form a solid waste-based ceramic wall material, and a double-layer core-shell structure high-temperature phase change energy storage capsule is obtained.

9. A high-temperature phase change energy storage capsule with a double-layer core-shell structure, characterized in that : The double-layer core-shell structure high-temperature phase change energy storage capsule is made by the preparation method according to any one of claims 1 - 8.

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