Solid waste-based phase change thermal storage material and responsive steam output system thereof

Abstract

The application provides a solid waste-based phase change heat storage material and a responsive steam output system thereof, and the phase change heat storage material is a core-shell structure, comprising a solid waste-based phase change core layer and a molten salt shell layer; the core layer is composed of a nano-porous silico-aluminate framework and in-situ grown silicon carbide nanowires; the molten salt shell layer is coated on the surface of the core layer; the core layer is prepared by the following method: firstly, coal-based solid waste is passed into a plasma gas stream to generate a plasma jet containing SiO and AlO active components; secondly, alkali metal chloride-containing atomized droplets are sprayed into the jet to form a silico-aluminate framework with a multi-level pore structure; and finally, silicon carbide nanowires are in-situ grown in the silico-aluminate framework through a carbothermic reduction reaction. One technical effect of the application is that the intrinsic low thermal conductivity of the solid waste material can be broken through to realize directional and rapid heat transport, and at the same time, the large temperature difference loss of a traditional heat exchanger can be eliminated to realize a steam response in seconds.

Description

Technical Field

[0001] This invention belongs to the field of solid waste resource utilization technology, specifically relating to a solid waste-based phase change thermal storage material and its responsive steam output system. Background Technology

[0002] In the field of solid waste-based phase change thermal energy storage materials and responsive steam output systems, the following key issues in the existing technology urgently need to be addressed.

[0003] Chinese invention patent CN116119959A discloses a micro-surface reinforced phase change energy storage aggregate, its preparation method, and its application. While it addresses issues such as high cost, low mechanical strength, and poor thermal conductivity of phase change energy storage materials to some extent, its thermal conductivity remains low, only 0.85~1.2 W / m·K, and it fails to achieve directional and rapid heat transport. Furthermore, this patent does not address second-level steam response technology, thus failing to meet the challenges of sudden changes in steam demand during grid peak shaving.

[0004] Chinese invention patent CN111129662A discloses a biomimetic heat dissipation and heat recovery system for batteries. Although it proposes an innovative solution in the field of battery thermal management, its technology has not been applied to solid waste-based phase change thermal storage materials. Furthermore, its system structure does not involve the efficient utilization of solid waste materials or the design of a biomimetic fractal microchannel steam generator, thus failing to achieve integrated heat storage and evaporation and second-level steam response.

[0005] Therefore, existing technologies have significant shortcomings in terms of efficient heat transfer and responsive steam output systems for solid waste-based phase change thermal energy storage materials. To address these issues, this application proposes a solid waste-based phase change thermal energy storage material and its responsive steam output system based on multi-level nano-confined heat transfer. The aim is to overcome the inherent low thermal conductivity limitation of solid waste materials, achieve directional and rapid heat transport, eliminate the large temperature difference loss of traditional heat exchangers, and achieve second-level steam response to meet the problem of sudden changes in steam demand under power grid peak shaving scenarios. Summary of the Invention

[0006] The present invention aims to solve at least one of the technical problems existing in the prior art, and to provide a new technical solution for solid waste-based phase change thermal storage materials and their responsive steam output system.

[0007] According to a first aspect of the present invention, a solid waste-based phase change thermal energy storage material is provided. The phase change thermal energy storage material has a core-shell structure, comprising an inner solid waste-based phase change core layer and an outer molten salt shell layer. The core layer is constructed using multi-level nano-confined heat transfer technology and consists of a nanoporous aluminosilicate framework and in-situ grown silicon carbide nanowires to form a three-dimensional network structure. The molten salt shell layer coats the surface of the core layer and serves as the phase change host, undergoing a solid-liquid phase change during heat absorption / release to achieve efficient energy storage. The core layer is prepared by the following method: First, coal-based solid waste is introduced into a plasma gas stream, and plasma disintegration, collision and excitation are performed to generate a plasma jet containing active components of SiO and AlO. Second, atomized droplets containing alkali metal chlorides are sprayed into the jet, and after gas-liquid reaction, hydrolysis, dehydration and crystal precipitation, a nanoscale Si-Al-OH precursor is formed in a micro-homogeneous environment. The precursor is then dehydrated, crystallized and sintered in situ to form a silicate framework with a multi-level porous structure. Finally, silicon carbide nanowires are grown in situ inside the silicate framework through a carbothermal reduction reaction.

[0008] Optionally, the molten salt in the molten salt shell is a Na2CO3-Li2CO3 eutectic mixture.

[0009] Optionally, the porosity of the nanoporous aluminosilicate framework is 75-85%, and the pore size is gradient-distributed in the range of 50 nm to 5 μm.

[0010] Optionally, the thermal conductivity of the silicon carbide nanowires is 350-450 W / (m·K).

[0011] Optionally, the phase transition temperature of the molten salt shell is 48~52℃, and the latent heat of phase transition is 100-150J / g.

[0012] According to a second aspect of the present invention, a responsive steam output system for a solid waste-based phase change thermal storage material is provided, comprising a microchannel heat exchanger, a piezoelectric valve, an inlet pipe, an outlet pipe, a first spray gun, a gas flow controller, a gas storage tank, a condenser, a gas storage chamber, an air compressor, a filter, and a second spray gun; the microchannel inner wall of the microchannel heat exchanger is provided with ribs, the ribs being triangular in shape; one end of the microchannel heat exchanger is connected to the inlet pipe, and the other end is connected to the outlet pipe; the first spray gun, the gas flow controller, and the gas storage tank are sequentially arranged on the inlet pipe from near the microchannel heat exchanger to away from the microchannel heat exchanger; the condenser, the gas storage chamber, the air compressor, the filter, and the second spray gun are sequentially arranged on the outlet pipe from near the microchannel heat exchanger to away from the microchannel heat exchanger; the piezoelectric valve is installed on one side of the gas storage chamber.

[0013] Optionally, the responsive steam output system of the solid waste-based phase change thermal storage material also includes an auxiliary refrigeration device; One end of the auxiliary refrigeration device is connected to the microchannel heat exchanger, and the other end is connected to the gas storage tank.

[0014] Optionally, the microchannel heat exchanger is made of stainless steel.

[0015] Optionally, the microchannel heat exchanger is filled with a high-efficiency polyol liquid working fluid with a boiling point higher than 200°C.

[0016] Optionally, the microchannel size of the microchannel heat exchanger is 200 μm.

[0017] One technical advantage of this invention is that: In the embodiments of this application, the nanoporous aluminosilicate framework prepared by plasma vaporization, combined with the three-dimensional continuous thermally conductive network formed by silicon carbide nanowires, and the innovative design of a biomimetic fractal microchannel steam generator and a predictive-response dual-mode control system, can effectively solve the shortcomings of the prior art, realize the efficient utilization of solid waste-based phase change thermal storage materials and the rapid response of the responsive steam output system, and provide a new technical path for the resource utilization of solid waste and the improvement of the flexibility of energy systems. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a solid waste-based phase change thermal storage material according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the performance comparison curves of a phase change material according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of a responsive steam output system for a solid waste-based phase change thermal storage material according to an embodiment of the present invention.

[0019] In the figure: 1. Nanoporous aluminosilicate framework; 2. Silicon carbide nanowires; 3. FeO-GNS nanosheets; 4. Molten salt shell layer; 5. Pores; 6. Solid waste-based phase change core layer; 7. Microchannel heat exchanger; 8. Piezoelectric valve; 9. Inlet pipe; 10. Exhaust pipe; 11. First spray gun; 12. Gas flow controller; 13. Gas storage tank; 14. Condenser; 15. Gas storage chamber; 16. Air compressor; 17. Filter; 18. Second spray gun; 19. Auxiliary refrigeration device; A. 30-minute temperature rise point (350℃) of the solid waste-based phase change heat storage material of this application; B. Paraffin phase change platform; C. Water calcium chloride phase change point. Detailed Implementation

[0020] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present application.

[0021] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0022] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0023] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0024] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0025] According to a first aspect of the invention, see Figure 1 This invention provides a solid waste-based phase change thermal storage material, which consists of a multi-level nano-confined heat transfer material encapsulated in a shell to form a solid waste-based phase change thermal storage material.

[0026] Specifically, the phase change thermal storage material has a core-shell structure, including an inner solid waste-based phase change core layer 6 and an outer molten salt shell layer 4. The core layer is constructed using multi-level nano-confined heat transfer technology and consists of a nanoporous aluminosilicate framework 1 and in-situ grown silicon carbide nanowires 2 to form a three-dimensional network structure. The molten salt shell layer coats the surface of the core layer and serves as the main body for phase change, undergoing a solid-liquid phase change during heat absorption / release to achieve efficient energy storage. The core layer is prepared by the following method: First, coal-based solid waste is introduced into a plasma gas stream, and plasma disintegration, collision and excitation are performed to generate a plasma jet containing active components of SiO and AlO. Second, atomized droplets containing alkali metal chlorides are sprayed into the jet, and after gas-liquid reaction, hydrolysis, dehydration and crystal precipitation, a nanoscale Si-Al-OH precursor is formed in a micro-homogeneous environment. The precursor is then dehydrated, crystallized and sintered in situ to form a silicate framework with a multi-level porous structure. Finally, silicon carbide nanowires are grown in situ inside the silicate framework through a carbothermal reduction reaction.

[0027] In the embodiments of this application, the nanoporous aluminosilicate framework prepared by plasma vaporization, combined with the three-dimensional continuous thermally conductive network formed by silicon carbide nanowires, and the innovative design of a biomimetic fractal microchannel steam generator and a predictive-response dual-mode control system, can effectively solve the shortcomings of the prior art, realize the efficient utilization of solid waste-based phase change thermal storage materials and the rapid response of the responsive steam output system, and provide a new technical path for the resource utilization of solid waste and the improvement of the flexibility of energy systems.

[0028] In one specific implementation, the latent heat of phase change of the phase change thermal storage material in the shell is determined by the following method: under steady-state conditions, the system temperature change curves 1, 2, and 3 are measured as the initial state, the charging process, and the heat storage process, respectively; the system temperature change curves are measured as the time after the heating source is removed.

[0029] Using 500g of water at an initial temperature of 25℃ as a reference, water, paraffin, calcium chloride hexahydrate (hydrated CaCl·6H2O), paraffin oxide, and Na2CO-LiCO were used as heat sources. The closed systems were heated by electric heating with equal mass, and the temperature rise of the systems within the same time period was compared. The temperature rise curves of different systems under the equal mass heating conditions of this embodiment are shown below. Figure 2 As shown. By Figure 2It is evident that the system temperature rises fastest when water is used as the heat source; however, its low thermal conductivity and low latent heat of phase change are among the main reasons for its low heat transfer efficiency. Adding CaCl₂·6H₂O significantly reduces the temperature rise, and its lower melting point increases the heat storage density. Adding paraffin further reduces the temperature rise, as paraffin not only provides insulation but also suppresses the risk of deflagration caused by direct contact between molten salt and water. Finally, the Na₂CO₃-LiCO₃ system exhibits the fastest and most stable temperature rise compared to other systems. In summary, this composite system demonstrates high safety performance, excellent thermal stability, and efficient heat storage capacity.

[0030] For details, see Figure 2 The performance comparison of phase change materials is explained below: The temperature rise curves (initial temperature 25°C) of different systems under the test conditions of equal mass heating are compared and analyzed as follows: Water: Initial temperature rises rapidly, but there is no latent heat of phase change, and the temperature rises slowly in the later stages.

[0031] Paraffin wax: The phase transition plateau is obvious (point B), and the temperature rise is slow.

[0032] Calcium chloride hexahydrate: has a lower melting point (point C) and a higher heat storage density.

[0033] Oxidized paraffin: It has the slowest temperature rise and a heat-insulating effect.

[0034] The Na2CO3-Li2CO3 eutectic mixture (i.e., this application) has the fastest and most stable temperature rise (point A) and no risk of deflagration.

[0035] Therefore, the application materials have the following advantages: Firstly, it has the fastest temperature rise rate: reaching 350℃ within 30 minutes.

[0036] Secondly, it has the most stable temperature rise curve: without drastic fluctuations.

[0037] Thirdly, it has the highest safety performance: preventing the risk of flash evaporation caused by contact between molten salt and water.

[0038] Fourthly, it has excellent thermal stability: phase transition temperature 48-52°C.

[0039] For example, FeO-GNS nanosheets 3 are disposed within the solid waste-based phase change core layer.

[0040] The solid waste-based phase change thermal energy storage material described in the application is prepared using plasma gasification technology and has the following characteristics: Core-shell structure: It features a three-dimensional thermally conductive network formed by a nanoporous aluminosilicate framework (core layer) and a molten salt encapsulation layer (shell layer). Silicon carbide nanowires penetrate the porous structure, creating a continuous thermally conductive gradient porosity. The pore size exhibits a gradient distribution within the range of 50 nm to 5 μm, and possesses a high porosity of 75-85%.

[0041] Enhanced heat transfer: The parameters of FeO-GNS nanosheets for enhancing interfacial heat transfer are as follows: thermal conductivity is 35.6 W / (m·K) (30 times higher than traditional materials); phase change temperature is 48-52℃ (Na2CO3-Li2CO3); latent heat of phase change is 100-150J / g; thermal cycling stability is >5000 cycles.

[0042] Optionally, the molten salt in the molten salt shell is a Na₂CO₃-Li₂CO₃ eutectic mixture. The low melting point of the molten salt shell allows it to melt and form a liquid shell at relatively low temperatures, which helps to reduce energy consumption and operating temperature.

[0043] Optionally, the porosity of the nanoporous aluminosilicate framework is 75-85%, and the pore size of pore 5 exhibits a gradient distribution in the range of 50 nm to 5 μm. The gradient pore size distribution enables a gradual attenuation of heat flow from the surface to the interior, further improving the overall thermal insulation efficiency, and achieving a multi-objective synergy of lightweight, high strength, efficient thermal insulation, rapid mass transfer, and high adsorption / catalytic activity.

[0044] Optionally, the silicon carbide nanowires have a thermal conductivity of 350-450 W / (m·K), which enables them to efficiently conduct heat. As a thermal interface material or thermally conductive filler, they can significantly improve the overall thermal conductivity of composite materials and solve the problem of "heat accumulation" in electronic devices and power modules.

[0045] Optionally, the phase transition temperature of the molten salt shell is 48~52℃, and the latent heat of phase transition is 100-150J / g. The moderate phase transition temperature makes it highly targeted for application, enabling precise heat absorption / release at critical temperature points, improving system thermal stability, and providing efficient thermal buffering within a limited space, extending the safe operating time of the equipment.

[0046] According to a second aspect of the invention, see Figure 3 This paper presents a responsive steam output system based on solid waste-based phase change thermal storage materials, which is suitable for scenarios such as distributed energy, building energy conservation, and power peak regulation.

[0047] Specifically, the responsive steam output system of the solid waste-based phase change thermal energy storage material includes a microchannel heat exchanger 7, a piezoelectric valve 8, an inlet pipe 9, an exhaust pipe 10, a first spray gun 11, a gas flow controller 12, a gas storage tank 13, a condenser 14, a gas storage chamber 15, an air compressor 16, a filter 17, and a second spray gun 18. The microchannel heat exchanger 7 has ribs on its inner wall, and the ribs are triangular in shape. One end of the microchannel heat exchanger 7 is connected to the inlet pipe 9, and the other end is connected to… The exhaust pipe 10 is connected; the intake pipe 7 is provided with a first spray gun 11, a gas flow controller 12, and a gas storage tank 13 in sequence from the direction near the microchannel heat exchanger to the direction away from the microchannel heat exchanger 7; the exhaust pipe 10 is provided with a condenser 14, a gas storage chamber 15, an air compressor 16, a filter 17, and a second spray gun 18 in sequence from the direction near the microchannel heat exchanger 7 to the direction away from the microchannel heat exchanger 7; the piezoelectric valve 8 is installed on one side of the gas storage chamber 15.

[0048] More specifically, the microchannel of the microchannel heat exchanger is surrounded by an insulating shell, and the interior of the microchannel is filled with a solid waste-based phase change thermal storage material as described in the first aspect.

[0049] The above implementation can realize directional and rapid heat transport, while eliminating the large temperature difference loss of traditional heat exchangers and achieving steam response in seconds, so as to meet the problem of sudden changes in steam demand under the peak shaving scenario of the power grid.

[0050] It should be noted that heat sources (such as solar energy, industrial waste heat, and nuclear energy) are often intermittent or fluctuating. Phase change materials (PCMs), on the other hand, absorb and store heat when the heat source is sufficient (e.g., by melting from a solid to a liquid state). When the heat source weakens or is interrupted, the PCM releases heat, continuously heating the working fluid and maintaining stable steam production in the steam system. This avoids steam pressure fluctuations and ensures the safe and stable operation of downstream equipment (such as steam turbines).

[0051] Optionally, the responsive steam output system of the solid waste-based phase change thermal storage material also includes an auxiliary refrigeration device 19; One end of the auxiliary refrigeration device 19 is connected to the microchannel heat exchanger 7, and the other end is connected to the gas storage tank 13.

[0052] In the above embodiments, the auxiliary refrigeration device utilizes the low-temperature characteristics of the gas storage tank or the heat absorption effect during the phase change process to provide additional cooling compensation for the microchannel heat exchanger, thereby achieving efficient, active or passive composite cooling.

[0053] Optionally, the microchannel heat exchanger is made of stainless steel. This helps to improve the strength and safety of the microchannel heat exchanger.

[0054] Optionally, the microchannel heat exchanger is filled with a high-efficiency polyol liquid working fluid with a boiling point higher than 200°C. This allows for stable operation in high-temperature environments, avoiding the safety risks caused by the violent vaporization and sudden pressure rise of traditional low-boiling-point working fluids at high temperatures.

[0055] Optionally, the microchannel size of the microchannel heat exchanger is 200 μm, which gives the microchannel heat exchanger an extremely high specific surface area, enhances heat transfer efficiency, and has an extremely short heat conduction path, reducing thermal resistance.

[0056] In this embodiment, the solid waste-based phase change thermal storage material based on multi-level nano-confined heat transfer and its responsive steam output system include two parts: the solid waste-based phase change thermal storage material based on multi-level nano-confined heat transfer and the biomimetic fractal microchannel steam generator.

[0057] Among them, the solid waste-based phase change thermal energy storage material with multi-stage nano-confined heat transfer is made by mixing alumina powder, kaolin, fly ash and quartz sand in a mass ratio of 1:1:1:1. After the powder is agglomerated, nanoporous aluminosilicate, silicon carbide nanowires and FeO-GNS nanosheets are added. Then, it is placed in a plasma gas flow and rapidly heated to 2300℃. The material is then prepared by rapid cooling spraying. The biomimetic fractal microchannel steam generator consists of a microchannel, a working fluid inlet, a working fluid outlet and a piezoelectric valve. The microchannel is covered with an insulating shell and filled with the solid waste-based phase change thermal energy storage material with multi-stage nano-confined heat transfer. The initial temperature of the working fluid inlet is 20℃. When the working fluid outlet water temperature reaches saturation, the piezoelectric valve is opened, so that the working fluid water vapor is sprayed out from the end of the microchannel in the form of a spray.

[0058] Preferably, the preparation method of the solid waste-based phase change thermal storage material is as follows: Step S1, raw material mixing: The alumina powder, kaolin, fly ash and quartz sand are mixed in a mass ratio of 1:1:1:1 and pre-pulverized in a ball mill for 10 minutes to obtain raw material powder.

[0059] Step S2, nano-skeleton prefabrication: The raw material powder obtained in step S1 is added to an ethanol aqueous solution containing F127 block copolymer (P123), ultrasonically dispersed and stirred for 24 hours to obtain a slurry.

[0060] Step S3, high-temperature carbonization: The slurry obtained in step S2 is transferred to a carbonization furnace, rapidly heated to 2300±50℃ and kept at a constant temperature for 5 hours, and then allowed to cool naturally at room temperature to obtain secondary powder containing nanoporous aluminosilicates.

[0061] Step S4, in-situ carbonization: Add sufficient anhydrous ethanol and nitrogen to the secondary powder obtained in step S3, ultrasonically disperse and stir for 24 hours, then transfer the slurry to a carbonization furnace, rapidly heat to 1700±50℃ and maintain constant temperature for 5 hours, and allow it to cool naturally at room temperature to obtain tertiary powder containing silicon carbide nanowires.

[0062] Step S5, confined encapsulation: FeO-GNS nanosheets are added to the tertiary powder containing nanoporous aluminosilicates. After thorough mixing, molten NaCO-LiCO eutectic alloy is added. Sodium hydroxide solution is slowly added dropwise to adjust the pH value to above 13 to ensure an alkaline environment. The resulting mixture is then encapsulated in a quartz test tube used in the experiment using capillary force.

[0063] Step S6, graded assembly: The obtained encapsulated sample is placed in a muffle furnace and calcined at 750±10℃ for 6 hours, and then cooled with the furnace to obtain a solid waste-based phase change thermal storage material based on multi-level nano-confined heat transfer.

[0064] In one specific implementation, the characterization method of the solid waste-based phase change thermal storage material based on multi-level nanoconfined heat transfer is as follows: Step S7, determine porosity based on precipitation titration: Take 1g of the final product from step S6 and soak it in 120mL of 6% hydrochloric acid for 12 hours to allow the Na2CO3-Li2CO3 eutectic salt encapsulated in the material pores to fully react. After centrifugation to remove insoluble solid particles, take the supernatant as the test solution. The chloride ion content is determined using the silver nitrate precipitation titration method, with the specific steps as follows: Measure the volume as V test (For example, 20.0 mL) of the above test solution is placed in an Erlenmeyer flask.

[0065] Add C to the conical flask AgNO3 The reaction equation for a 0.02 mol / L silver nitrate standard solution is: Ag + +Cl - →AgCl↓.

[0066] The titration process was monitored using a potentiometric titrator, where pH was the reference electrode potential and PA(PCl) was the instantaneous potential of the measuring electrode during chloride ion titration. The titration endpoint was determined when the potential difference ΔP = PH - PA(PCl) reached 2.5 kPa (a specific potential value after calibration). The volume V of silver nitrate standard solution consumed at this point was recorded. AgNO3 .

[0067] Porosity is calculated using the following formula: Calculate the total amount of chloride ions n in the pores Cl (mol): ; Calculate the total pore volume Vpores (cm³): ; Wherein, K (cm) 3 / mol) is the pore volume conversion factor, which is obtained by calibration using a model porous material with known geometric volume.

[0068] Calculate the apparent volume Vtotal (cm³) of the material (obtained by measuring the geometric dimensions of the material or using the hydrometer bottle method).

[0069] Calculate the porosity ε (%). Divide the total volume of the calculated pores by the apparent volume of the material to obtain the percentage of pores, i.e., the porosity.

[0070] Step S8, analyze the surface morphology and pore distribution based on scanning electron microscopy: observe the microstructure of the sample using a microscope with magnification of 80-1500x.

[0071] Furthermore, the fabrication method of the biomimetic fractal microchannel steam generator (i.e., microchannel heat exchanger) is as follows: Step S9, Microchannel Network Forming: The final product from Step S6 is added to the microchannel mold and filled with molten paraffin for negative pressure degassing treatment, then cast and cooled to room temperature.

[0072] Step S10, Microchannel Etching: First, dilute the silicone and curing agent at a ratio of 10:1, mix them evenly, and ultrasonically disperse them for 30 minutes; then, inject the mixed slurry into a microchannel mold and invert it for 10 minutes to remove air bubbles, and place it in a 40℃ oven to cure into a film for 4 hours; finally, embed the silicone mold containing the microchannels into a CaCl solution and soak it for 15 minutes to obtain a copy, place the copy in acetone for ultrasonic cleaning for 20 minutes and dry it to obtain a microchannel with a micro-groove microstructure. Step S11, Microchannel array formation: A 500nm thick Al film is deposited on the surface of the microchannels obtained in step S10 using photolithography and magnetron sputtering techniques and then annealed for 24h.

[0073] Preferably, the preparation method of the predictive-response dual-mode control system is as follows: Step S12, predict steam consumption based on LSTM neural network: collect historical steam consumption data to train LSTM neural network model, so as to accurately predict future steam consumption; when the predicted steam consumption starts to rise and exceeds the threshold, turn on the power supply to prepare for power generation.

[0074] Step S13, Power switch control: Due to the overshoot problem of LSTM neural network, in order to ensure stable output of steam consumption and prevent fluctuations that could cause boiler shutdown, the power is turned off when a decrease in steam consumption is detected and it falls below the threshold.

[0075] The beneficial effects of this invention are as follows: This invention discloses a solid waste-based phase change thermal energy storage material and its responsive steam output system based on multi-level nano-confined heat transfer. It overcomes the inherent low thermal conductivity limitation of solid waste materials, enabling precise and controllable heat flux output within a specific range from room temperature to 350°C. Furthermore, its integration of a multi-level nano-confined heat transfer structure with solid-state phase change thermal energy storage eliminates the leakage risk associated with traditional liquid phase change materials.

[0076] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A solid waste-based phase change thermal storage material, characterized in that, The phase change thermal storage material has a core-shell structure, comprising an inner solid waste-based phase change core layer and an outer molten salt shell layer. The core layer is constructed using multi-level nanoconfined heat transfer technology and consists of a nanoporous aluminosilicate framework and in-situ grown silicon carbide nanowires to form a three-dimensional network structure. The molten salt shell layer coats the surface of the core layer and serves as the main body for phase change, undergoing a solid-liquid phase change during heat absorption / release to achieve efficient energy storage. The core layer is prepared by the following method: First, coal-based solid waste is introduced into a plasma gas stream, and plasma disintegration, collision and excitation are performed to generate a plasma jet containing active components of SiO and AlO. Second, atomized droplets containing alkali metal chlorides are sprayed into the jet, and after gas-liquid reaction, hydrolysis, dehydration and crystal precipitation, a nanoscale Si-Al-OH precursor is formed in a micro-homogeneous environment. The precursor is then dehydrated, crystallized and sintered in situ to form a silicate framework with a multi-level porous structure. Finally, silicon carbide nanowires are grown in situ inside the silicate framework through a carbothermal reduction reaction.

2. The solid waste-based phase change thermal storage material according to claim 1, characterized in that, The molten salt in the molten salt shell is a Na2CO3-Li2CO3 eutectic mixture.

3. The solid waste-based phase change thermal storage material according to claim 1, characterized in that, The aforementioned nanoporous aluminosilicate framework has a porosity of 75-85% and a gradient distribution of pore size in the range of 50 nm to 5 μm.

4. The solid waste-based phase change thermal storage material according to claim 1, characterized in that, The thermal conductivity of the silicon carbide nanowires is 350-450 W / (m·K).

5. The solid waste-based phase change thermal storage material according to claim 1, characterized in that, The phase transition temperature of the molten salt shell is 48~52℃, and the latent heat of phase transition is 100-150J / g.

6. A responsive steam output system for solid waste-based phase change thermal storage materials, characterized in that, The system includes a microchannel heat exchanger, a piezoelectric valve, an inlet pipe, an exhaust pipe, a first spray gun, a gas flow controller, a gas storage tank, a condenser, a gas storage chamber, an air compressor, a filter, and a second spray gun. The microchannels of the microchannel heat exchanger have triangular ribs on their inner walls. One end of the microchannel heat exchanger is connected to the inlet pipe, and the other end is connected to the exhaust pipe. The inlet pipe, from the direction closest to the microchannel heat exchanger to the direction furthest away from it, is sequentially equipped with the first spray gun, the gas flow controller, and the gas storage tank. The exhaust pipe, from the direction closest to the microchannel heat exchanger to the direction furthest away from it, is sequentially equipped with the condenser, the gas storage chamber, the air compressor, the filter, and the second spray gun. The piezoelectric valve is installed on one side of the gas storage chamber.

7. The responsive steam output system for solid waste-based phase change thermal storage material according to claim 6, characterized in that, It also includes auxiliary refrigeration devices; One end of the auxiliary refrigeration device is connected to the microchannel heat exchanger, and the other end is connected to the gas storage tank.

8. The responsive steam output system for solid waste-based phase change thermal storage material according to claim 6, characterized in that, The microchannel heat exchanger is made of stainless steel.

9. The responsive steam output system for solid waste-based phase change thermal storage materials according to claim 6, characterized in that, The microchannel heat exchanger is filled with a high-efficiency polyol liquid working fluid with a boiling point higher than 200°C.

10. The responsive steam output system for solid waste-based phase change thermal storage materials according to claim 6, characterized in that, The microchannel size of the microchannel heat exchanger is 200 μm.

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