CN110142838B

CN110142838B - Preparation method of phase change energy storage wood with carbon-coated metal filler

Info

Publication number: CN110142838B
Application number: CN201910479145.7A
Authority: CN
Inventors: 刘毅; 李彦辰; 杨颖妮; 王蓓蓓; 方晓阳; 赵俊淇; 夏容绮; 张伟业
Original assignee: Beijing Forestry University
Current assignee: Beijing Forestry University
Priority date: 2019-06-04
Filing date: 2019-06-04
Publication date: 2020-11-20
Anticipated expiration: 2039-06-04
Also published as: CN110142838A

Abstract

The invention discloses a preparation method of phase change energy storage wood with carbon-coated metal filler. The composite particle is a double-layer core-shell structure composite material. Using nano Al particles with the average particle size of 40-50 as a core body, and coating Ti on the surface₄O₇And CQD_SAnd preparing the heat-conducting composite nano particles as a shell. And then the phase-change material is taken as a heat-conducting filler to be fully mixed with PEG-800, and the wood is impregnated by the phase-change material by adopting a vacuum pressurization method, so that the novel phase-change energy-storage wood capable of adjusting the room temperature is prepared. The invention adopts Ti₄O₇And CQD_SThe grafting is carried out on the nano Al powder, so that the heat conduction efficiency of the nano Al can be effectively improved, and the problem of agglomeration of the nano Al powder in an organic solvent is solved, so that the nano Al powder can be impregnated into cell walls through wood micropores, and the effect of shaping and packaging is achieved. The prepared phase change energy storage wood has ultraviolet-visible-infrared full-light-section absorption capacity, can efficiently convert solar energy into internal energy, and realizes the functions of storage and heat release.

Description

Preparation method of phase change energy storage wood with carbon-coated metal filler

(I) technical field

The invention relates to a preparation method of phase change energy storage wood with carbon-coated metal filler, in particular to nano Al/Ti₄O₇/CQD_SCore-shell structured photocatalytic composite particles.

(II) background of the invention

In recent years, the problems of energy conservation and environmental protection become one of the important factors influencing the development of socioeconomic performance. With the rapid development of the industrial society, the demand and the dependence degree of human beings on energy are increasingly strengthened, and the attention is increasingly paid to the development of novel green energy, the improvement of the energy utilization rate, the research and development of energy-saving technology and materials. The energy storage technology is developed at the same time, not only can reduce industrial production energy consumption and recover waste heat, but also can transfer redundant energy in a heat utilization valley period to a heat utilization peak period for use, and in addition, clean energy such as solar energy, geothermal energy and the like can be absorbed and utilized. The technology can effectively overcome the mismatching of heat energy supply and demand in time and space, reduce the consumption of non-renewable fossil energy, improve the utilization rate of energy and reduce environmental pollution. Currently, the commonly used energy storage technologies include sensible energy storage, chemical energy storage, and latent heat storage. Among the heat energy storage technologies, the latent heat energy storage density is high, the system temperature is basically constant in the energy storage process, the temperature of the surrounding environment can be regulated, and the method is the most promising energy storage mode at present. The phase-change material can absorb heat energy through phase change under the heating condition, release the heat energy in the cooling process, realize the storage and release of the heat energy according to different environmental temperatures, and effectively overcome the space-time limitation of heat energy supply. The organic solid-liquid phase change material is a relatively mature phase change material at present, has many types and wide temperature application range, but has the defects of low thermal conductivity, small density, easy loss and the like, so that the preparation of the composite phase change material to improve the performance of the single organic solid-liquid phase change material in practical application becomes the key point of the current research.

The compounding is an important trend of modern material development, and the innovative improvement and the cooperative optimization of the material performance can be realized through compounding different materials. The composite phase-change material is prepared by compounding two or more materials, so that the defects of low thermal conductivity, supercooling and phase separation phenomena, easy leakage in phase change and the like of a single phase-change material in the actual application process are overcome, the application value of the phase-change material is improved, and generally, heat-conducting particles, such as metal particles, are added into the phase-change material to enhance the heat-conducting property of the phase-change material. Researches show that the nano Al particles have high thermal conductivity and good reaction activityThe material has large specific surface area and is an excellent heat conduction enhanced material. However, nano Al is easily agglomerated in an organic solvent, has poor dispersibility, and is very easily oxidized in air, so that an oxide layer with a thickness of several nanometers is generated, and the heat conduction efficiency is affected. Therefore, it is necessary to perform surface modification treatment on the organic polymer, or add an auxiliary agent to enhance uniform dispersion and stability in an organic solvent, and enhance wettability with an organic polymer. Ti₄O₇The titanium black is commonly called as titanium black, has excellent heat resistance, good acid resistance, alkali resistance and solvent resistance, good dispersibility in organic solvents such as water, resin and the like, is nontoxic and environment-friendly, and is a new energy material and a photocatalytic additive with strong activity. If the nano Al is grafted to the surface of the nano Al, a heterogeneous coating layer can be formed, and the photocatalytic performance and the oxidation resistance of the nano Al are improved. But Ti₄O₇The utilization rate of sunlight is low, and the sunlight can only be excited by ultraviolet light with shorter wavelength, so that the application of the sunlight is severely restricted. Therefore, only Ti is used₄O₇Coating the nano Al can not achieve ideal heat conduction effect. The invention also selects CQD_SSecondary coating of nano Al, CQD_SThe nano material is a quasi-zero-dimensional nano material, has stable structure, resists strong acid, strong alkali and light corrosion, and is easy to realize surface functionalization. It is reacted with Ti₄O₇The ultraviolet absorption can be expanded to the visible light range by compounding, because the visible light accounts for 43 percent of solar energy, and the ultraviolet only accounts for 5 percent, the two kinds of nano particles can reduce the band gap on the surface of the nano Al, so that the compound heat-conducting particles not only have the full-light-section light absorption capability, but also have extremely strong heat-conducting property, and can be well dispersed in an organic solvent. The phase-change material can be used as a heat-conducting filler to be blended with polyethylene glycol to prepare a phase-change energy storage material, and finally, the phase-change energy storage material is used for impregnating wood by a vacuum-pressurization method, so that the wood can obtain long-term and high-efficiency energy storage capacity. The product has the characteristics of energy conservation, environmental protection, room temperature balance and degradability, can be used for decoration of buildings, furniture and interior decoration, and creates a green, environment-friendly, energy-saving and comfortable working and living environment for people.

Disclosure of the invention

The invention aims to graft Ti by using nano Al conjugate₄O₇And CQD_SPreparing core-shell structured photocatalytic composite particles, then taking the core-shell structured photocatalytic composite particles as a heat-conducting filler and blending the core-shell structured photocatalytic composite particles with polyethylene glycol to prepare a phase-change energy storage material, and finally impregnating the phase-change energy storage material into wood by using a vacuum-pressurization method to ensure that the wood obtains long-term and high-efficiency energy storage capacity

The technical scheme of the invention is as follows:

a method for preparing phase change energy storage wood with carbon-coated metal filler. The composite particle is a double-layer core-shell structure composite material. Using nano Al particles with the average particle size of 40-50 as a core body, and coating Ti on the surface₄O₇And CQD_SAs a shell, the all-optical-segment heat-conducting composite nano particles are prepared. And then the phase-change material is taken as a heat-conducting filler to be fully mixed with PEG-800, and the wood is impregnated by the phase-change material by adopting a vacuum pressurization method, so that the novel phase-change energy storage wood capable of adjusting the room temperature is prepared. The method specifically comprises the following steps:

(1) firstly, placing the sliced wood in water, vacuumizing (-0.1MPa for 1h), and exhausting air in the wood. Then NaOH and Na with the mass ratio of 1 percent and 0.5 percent are prepared₂SO₃Heating the mixed solution to 95 ℃, and then putting the wood into the mixed solution to be steamed for 24 hours (the mixed solution is replaced for 3-4 times in the process). And finally, placing the cooked wood in an ethanol boiling solution at 78 ℃ for 1h, and replacing the water in the wood. The prepared wood is preserved in absolute ethyl alcohol.

(2) Weighing appropriate amount of nano Al and Ti₄O₇And carboxylated CQD of 5mg/ml_SThe mass ratio is 2:1:1 for standby. And preparing a mixed solution of ethanol and deionized water with a mass ratio of 9:1 to ensure that the mixed solution can completely immerse the nanoparticles. Then adding a proper amount of silane coupling agent KH-550 with the dosage of nano Al and Ti₄O₇And CQD_S4 percent of the total mass. And adjusting the pH value of the mixed solution to 3-4 by using oxalic acid, and standing at room temperature for 1 hour to obtain a solvent A for later use.

(3) Under the protection of nitrogen, firstly adding nano Al particles into the solvent A, stirring at a high speed for 20min, and then performing ultrasonic dispersion at 300W for 30 min. Then adding Ti₄O₇Particles and CQD_SStirring at high speed for 1 hr, and stirring again at 300 deg.CUltrasonic treatment is carried out for 1h under W, and the temperature is controlled to be 45 ℃ in the whole process. Then refluxed at 90 ℃ for 2 h. Finally, vacuum-pumping filtration, acetone washing and drying at 50 ℃ for 24 hours are carried out to obtain the nano Al grafted Ti₄O₇And CQD_S

(4) Weighing a proper amount of PEG-800, placing the PEG-800 in a constant-temperature water bath kettle at 50 ℃ until the PEG-800 is melted, then adding a proper amount of absolute ethyl alcohol, and stirring the mixture at a high speed for 1 hour, wherein the mass ratio of the PEG-800 to the absolute ethyl alcohol is 7: 3. Weighing 2 w% of Al grafted Ti₄O₇And CQD_SMixing with PEG-800, stirring at high speed for 2 hr, and ultrasonic dispersing at 500w for 30min to obtain phase change energy storage suspension.

(5) And (4) impregnating the phase change energy storage material prepared in the step (4) into wood by using a vacuum-pressurization method. Firstly, vacuumizing a pretreated wood test piece at 90 ℃, enabling the vacuum degree to reach-0.1 MPa, injecting a phase change energy storage suspension under the negative pressure condition, keeping the pressure for 30min, and then recovering the normal pressure; pressurizing the impregnation tank to 1.2MPa, maintaining the pressure for 3 hours and then releasing the pressure; the vacuum degree of the post-vacuum is also-0.1 MPa, and the vacuumizing time is 10 min. And naturally drying the test piece for 48h, and then slowly drying the test piece in a drying oven at a low temperature of 60 ℃ until the quality is constant, thereby obtaining the phase change energy storage wood.

The method has the following advantages:

(1) the reaction condition is easy to control, and the operation is convenient and simple.

(2) The functionalized coated nano Al has good dispersibility and all-optical-segment absorption capacity, the oxidation process is prevented, and the heat conduction efficiency is improved.

(3) The functionalized coated nano Al is dispersed into PEG-800, the heat storage and release capacity and the loss resistance of the PEG-800 are improved, and then the phase change energy storage material is shaped and packaged by taking wood as a support body, so that the wood has the capacity of regulating the room temperature, and the energy saving is facilitated.

(IV) description of the drawings

FIG. 1 is a technical scheme of the invention

(V) detailed description of the preferred embodiments

Example 1

A preparation method of phase change energy storage wood with carbon-coated metal filler comprises the following steps:

(1) selecting Pinus densiflora, selecting mature saplings with a height above the chest, wherein the specification is that the saplings are 20mm long, 20mm wide and 20mm thick, and have no defects of cracking, decay, discoloration and the like. After weighing, the wood test piece is placed in deionized water, vacuumized (-0.1MPa, 1h) and the air in the wood is discharged.

(2) 500ml of deionized water was poured into a beaker, and then 5g of NaOH and 2.5g of Na were added₂SO₃And after heating to 95 ℃, putting the wood into the mixed solution for cooking for 24 hours (the mixed solution is replaced for 3-4 times in the process), wherein the wood is ensured to be immersed in the solution. And finally, placing the cooked wood in an ethanol boiling solution at 78 ℃ for 1h, and replacing the water in the wood. The prepared wood is preserved in absolute ethyl alcohol.

(3) Weighing 1g of nano Al and 0.5g of Ti₄O₇And 0.5g carboxylated CQD at 5mg/ml_SThe mass ratio of 2:1:1, standby. 4.5ml of deionized water and 0.5ml of absolute ethanol were weighed and mixed. Then 0.08g of silane coupling agent KH-550 is added dropwise. And adjusting the pH value of the mixed solution to 3-4 by using oxalic acid, and standing at room temperature for 1 hour to obtain a solvent A for later use.

(4) Under the protection of nitrogen, firstly adding nano Al particles into the solvent A, stirring at a high speed for 20min, and then performing ultrasonic dispersion at 300W for 30 min. Then adding Ti₄O₇Particles and CQD_SStirring at high speed for 1h, and then performing ultrasonic treatment at 300W for 1h, wherein the temperature is controlled at 45 ℃ in the whole process. Then refluxed at 90 ℃ for 2 h. Finally, vacuum-pumping filtration, acetone washing and drying at 50 ℃ for 24 hours are carried out to obtain the nano Al grafted Ti₄O₇And CQD_S

(5) 70g of PEG-800 is weighed and placed in a constant temperature water bath kettle at 50 ℃ until being melted, and then 30g of absolute ethyl alcohol is added to be stirred for 1 hour at a high speed. Grafting nano Al to Ti₄O₇And CQD_SMixing with PEG-800, stirring at high speed for 2 hr, and ultrasonic dispersing at 500w for 30min to obtain phase change energy storage suspension.

(6) And putting the phase change energy storage suspension and the wood test piece into an impregnation tank together. Firstly, vacuumizing a pretreated wood test piece at 90 ℃, enabling the vacuum degree to reach-0.1 MPa, injecting a phase change energy storage suspension under the negative pressure condition, keeping the pressure for 30min, and then recovering the normal pressure; pressurizing the impregnation tank to 1.2MPa, maintaining the pressure for 3 hours and then releasing the pressure; the vacuum degree of the post-vacuum is also-0.1 MPa, and the vacuumizing time is 10 min. And naturally drying the test piece for 48h, and then slowly drying the test piece in a drying oven at a low temperature of 60 ℃ until the quality is constant, thereby obtaining the phase change energy storage wood.

Example 2

(1) selecting southern pine, selecting mature sapwood with a chest height above, wherein the specification is 30m long, 30mm wide and 20mm thick, and the southern pine has no defects of cracking, decay, discoloration and the like. After weighing, the wood test piece is placed in deionized water, vacuumized (-0.1MPa, 1h) and the air in the wood is discharged.

(2) 1000ml of deionized water was poured into a beaker, then 10g of NaOH and 5g of Na were added₂SO₃And after heating to 95 ℃, putting the wood into the mixed solution for cooking for 24 hours (the mixed solution is replaced for 3-4 times in the process), wherein the wood is ensured to be immersed in the solution. And finally, placing the cooked wood in an ethanol boiling solution at 78 ℃ for 1h, and replacing the water in the wood. The prepared wood is preserved in absolute ethyl alcohol.

(3) Weighing 2g of nano Al and 1g of Ti₄O₇And 1g carboxylated CQD at 5mg/ml_SThe mass ratio is 2:1:1 for standby. 9ml of deionized water and 1ml of absolute ethanol were weighed and mixed. Then 0.16g of silane coupling agent KH-550 is added dropwise. And adjusting the pH value of the mixed solution to 3-4 by using oxalic acid, and standing at room temperature for 1 hour to obtain a solvent A for later use.

(5) 140g of PEG-800 is weighed and placed in a constant temperature water bath kettle at 50 ℃ until being melted, and then 60g of absolute ethyl alcohol is added to be stirred for 1 hour at high speed. Grafting nano Al to Ti₄O₇And CQD_SAnd PEG-800, stirring at high speed for 2h, and then ultrasonically dispersing for 30min under 500w to prepare the phase change energy storage suspension.

Claims

1. A preparation method of phase change energy storage wood with carbon-coated metal filler is characterized by comprising the following steps:

(1) firstly, placing the sliced wood in water, vacuumizing for 1h under-0.1 MPa, discharging the air in the wood, and then preparing NaOH and Na with the mass ratio of 1% and 0.5%₂SO₃Heating the mixed solution to 95 ℃, putting the wood into the mixed solution, cooking for 24h, replacing the mixed solution for 3-4 times in the cooking process, finally putting the cooked wood into an ethanol boiling solution at 78 ℃ for 1h, replacing the water in the wood, and storing the prepared wood in absolute ethanol;

(2) weighing appropriate amount of nano Al and Ti₄O₇And carboxylated CQD of 5mg/ml_SThe mass ratio of the solution to the nano particles is 2:1:1, preparing a mixed solution of ethanol and deionized water for later use, the mass ratio of the solution to the nano particles is 9:1, ensuring that the mixed solution can completely immerse the nano particles, and then dropwise adding a proper amount of silane coupling agent KH-550, the dosage of which is nano Al and Ti₄O₇And CQD_SAdjusting the pH of the mixed solution to 3-4 by oxalic acid according to 4% of the total mass, and standing for 1h at room temperature to obtain a solvent A for later use;

(3) under the protection of nitrogen, firstly adding nano Al particles into the solvent A, stirring at a high speed for 20min, then ultrasonically dispersing at 300W for 30min, and then adding Ti₄O₇Particles and CQD_SStirring at high speed for 1h, performing ultrasonic treatment at 300W for 1h, controlling the whole process temperature at 45 ℃, refluxing at 90 ℃ for 2h,finally, vacuum-pumping filtration, acetone washing and drying at 50 ℃ for 24 hours are carried out to obtain the nano Al grafted Ti₄O₇And CQD_S；

(4) Weighing an appropriate amount of PEG-800, placing in a 50 ℃ constant temperature water bath until the PEG-800 is melted, then adding an appropriate amount of absolute ethyl alcohol, stirring at high speed for 1h, wherein the mass ratio of the PEG-800 to the absolute ethyl alcohol is 7:3, and weighing 2 w% of nano Al grafted Ti₄O₇And CQD_SMixing with PEG-800, stirring at high speed for 2h, and ultrasonic dispersing at 500w for 30min to obtain phase change energy storage suspension;

(5) impregnating the wood with the phase change energy storage suspension prepared in the step 4 by using a vacuum-pressurization method, firstly vacuumizing a pretreated wood test piece at 90 ℃, keeping the vacuum degree to-0.1 MPa, injecting the phase change energy storage suspension under the negative pressure condition, maintaining the pressure for 30min, recovering the normal pressure, pressurizing the impregnation tank to 1.2MPa, and releasing the pressure after maintaining the pressure for 3 h; and (3) the vacuum degree of the post vacuum is-0.1 MPa, the vacuumizing time is 10min, the test piece is naturally dried for 48h, and then the test piece is placed into a drying oven to be slowly dried at a low temperature of 60 ℃ until the quality is constant, so that the phase change energy storage wood is obtained.

2. The method of claim 1, wherein the wood in step (1) is one of red pine and southern pine.