CN115448670A - Packaged molten salt high-temperature heat storage concrete and preparation method thereof - Google Patents

Packaged molten salt high-temperature heat storage concrete and preparation method thereof Download PDF

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CN115448670A
CN115448670A CN202211249651.5A CN202211249651A CN115448670A CN 115448670 A CN115448670 A CN 115448670A CN 202211249651 A CN202211249651 A CN 202211249651A CN 115448670 A CN115448670 A CN 115448670A
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molten salt
salt particles
heat storage
encapsulated
size
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CN115448670B (en
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陶鹏
刘轶哲
徐扬哲
谢逸轩
邓涛
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Shanghai Jiaotong University
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    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
    • C04B28/04—Portland cements
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B14/00—Use of inorganic materials as fillers, e.g. pigments, for mortars, concrete or artificial stone; Treatment of inorganic materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone
    • C04B14/38—Fibrous materials; Whiskers
    • C04B14/386—Carbon
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B20/00—Use of materials as fillers for mortars, concrete or artificial stone according to more than one of groups C04B14/00 - C04B18/00 and characterised by shape or grain distribution; Treatment of materials according to more than one of the groups C04B14/00 - C04B18/00 specially adapted to enhance their filling properties in mortars, concrete or artificial stone; Expanding or defibrillating materials
    • C04B20/10—Coating or impregnating
    • C04B20/1055—Coating or impregnating with inorganic materials
    • C04B20/1066—Oxides, Hydroxides
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
    • C04B28/06—Aluminous cements
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
    • C04B28/06—Aluminous cements
    • C04B28/065—Calcium aluminosulfate cements, e.g. cements hydrating into ettringite
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/34—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing cold phosphate binders
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/14—Thermal energy storage

Abstract

The invention belongs to the field of high-temperature phase change heat storage materials, in particular to packaging molten salt high-temperature heat storage concrete and a preparation method thereof, the encapsulated molten salt high-temperature heat storage concrete is prepared from the following components in parts by weight: <xnotran> : </xnotran> 10-18 parts of molten salt particles: 65-75 part(s) of enhancing heat conduction material: 4-8 parts of water: 7-12 parts of a water reducing agent: 0.1-1 part by weight, encapsulating the fused salt particles by a ceramic material to form a ceramic shell, then adding water into the encapsulated fused salt particles, cement and the reinforced heat conduction material for mixing and stirring, and finally pouring and molding to obtain the encapsulated fused salt high-temperature heat storage concrete. According to the invention, the ceramic shell is used for packaging, so that the moistureproof and sizing effects on the fused salt can be realized, the fused salt and the cement can be physically separated, the problems of corrosion and pulverization of the fused salt on concrete are solved, the stability of the cement and the high-temperature structural strength of the composite material are improved, and the application potential of the high-temperature fused salt phase-change heat storage material is greatly improved.

Description

Packaged molten salt high-temperature heat storage concrete and preparation method thereof
Technical Field
The invention relates to the field of high-temperature phase-change heat storage materials, in particular to a packaged fused salt high-temperature heat storage concrete and a preparation method thereof.
Background
In recent years, with the rapid development of national economy, the total demand of society for energy is increasing, but from the viewpoint of energy supply and sustainability of natural environment, the traditional fossil energy cannot meet the demand of social development, and the development and utilization of renewable energy sources such as solar energy and wind energy are in need. In the global energy consumption process, the consumption ratio of the heat energy exceeds 50%, so the development of renewable heat energy technology is very important. The heat storage technology is a core means for effectively solving the problem of unmatched supply and demand of the renewable energy and improving the stability and the utilization rate of the renewable energy, and is widely applied to the fields of solar photo-thermal utilization, flexible reconstruction of power plants, clean heating, industrial waste heat and waste heat recovery, peak clipping and valley filling of electric power, building energy conservation and the like.
High performance heat storage the material is the core of advanced heat storage technology. The heat storage materials can be classified into sensible heat storage, phase-change latent heat storage, and chemical heat storage materials. The sensible heat storage utilizes the rise of the temperature of materials to store heat, and is a large-scale heat storage technology which has the highest maturity and is most widely applied at present. The phase-change latent heat storage is to utilize the solid-liquid phase-change process of the material to absorb/release heat, realize the storage and release of a large amount of latent heat, has the advantages of high heat storage density (5-10 times of sensible heat energy storage), stable heat storage/release temperature, easy control and the like, and is a novel heat storage material with the most potential. The sensible heat storage material and the phase-change material are compounded to prepare the composite heat storage material, the advantages of the sensible heat storage material and the phase-change material are expected to be combined, and the composite heat storage material is an important direction for the development of the current heat storage technology. In the solid-liquid phase change material, the medium-high temperature molten salt has the characteristics of high use temperature, good thermal stability, large specific heat capacity, high convective heat transfer coefficient, low viscosity, low saturated steam pressure, low price and the like, and has wide application prospect in the high-temperature heat transfer and storage fields of solar thermal power generation, nuclear power and the like. However, the fused salt phase-change heat storage material has the problems of serious hygroscopicity, strong corrosivity, easy leakage after solid-liquid phase change, poor high-temperature structural strength and the like. In order to solve the existing problems, the currently studied improvement strategy is to encapsulate the molten salt with a polymer or metal material, so as to isolate the molten salt from the external environment and form a stable structure. However, the working temperature of the polymer shell is limited, and the application requirement of high-temperature molten salt is difficult to meet; the unit density of the metal shell is high, the energy storage density of the composite material is greatly reduced, and the shell is easy to corrode, complex in production process and high in cost. In the preparation process of the sensible heat storage and phase change heat storage composite material, ceramics, clay and the like are mainly selected as the base body of the molten salt phase change material at present, and the composite material is prepared through the processes of high-temperature sintering, carbonization and the like, so that the energy consumption is huge, and the serious pollution to the atmosphere, soil and water resources is often caused. The cement as the cementing material can bond granular or blocky materials into a whole through self physical and chemical changes, so that the energy consumption caused by a high-temperature preparation process is avoided. Meanwhile, the concrete material formed by the cement also has the characteristics of low cost, easy processing, high specific heat and good mechanical property.
Disclosure of Invention
In order to solve the problems of easy moisture absorption, easy leakage and poor high-temperature mechanical property of the existing fused salt phase change heat storage material, the invention innovatively provides the packaged fused salt high-temperature heat storage concrete and the preparation method thereof. The ceramic shell can separate the fused salt from the external environment, eliminates the influence of the fused salt on the cement matrix, solves the problems of easy moisture absorption, easy leakage and poor high-temperature mechanical property of the fused salt, and can obtain a high-temperature heat storage composite material system which has obvious cost advantage and is simple to prepare and takes the cement as the matrix.
The technical scheme of the invention is as follows: the high-temperature heat storage concrete for encapsulating the molten salt is prepared from cement: 10-18 parts by weight of molten salt particles: 65-75 parts by weight of reinforced heat conducting material: 4-8 parts by weight of water: 7-12 parts by weight of water reducing agent: 0.1 to 1 part by weight, and the ceramic shell is formed by encapsulating molten salt particles by ceramic materials, and then mixing and stirring the packaged molten salt particles, cement and reinforced heat conducting material with water, and finally pouring and molding to obtain the packaged molten salt high-temperature heat storage concrete.
The packaged molten salt particles comprise large-particle-size packaged molten salt particles, medium-particle-size packaged molten salt particles and small-particle-size packaged molten salt particles, wherein the size of the large-particle-size packaged molten salt particles is more than 20-40 mm; the size of the medium-particle size packaging molten salt particles is more than 5-20 mm; the size of the small-particle-size packaging molten salt particles is 0.155-5 mm.
Preferably, the cement is one or more of sulphoaluminate cement, portland cement, aluminate cement, low-calcium aluminate cement, calcium magnesium aluminate cement, ferro-aluminate cement, fluoroaluminate cement and phosphate cement. The cement is an inorganic cementing material, is added with water and stirred to form slurry, can be hardened in air or in water, can uniformly and firmly glue together packaged molten salt particles, reinforced heat conduction materials and the like, and has the main function of cementing solid materials into a whole and providing certain mechanical strength.
Further, the core material of the encapsulating molten salt particles is high-temperature molten salt.
Preferably, the high-temperature molten salt is one or more of alkali metal or alkaline earth metal and halide, silicate, carbonate, nitrate and phosphate.
Most preferably, the high temperature molten salt is a eutectic molten salt of lithium carbonate, sodium carbonate and sodium carbonate.
Further, the ceramic shell is made of high-heat-conductivity and corrosion-resistant ceramic material. Most preferably, the ceramic shell may be titania/zirconia. The precursor for forming the ceramic shell is tetrabutyl titanate and zirconium n-propoxide.
Further, the reinforced heat conduction material can be steel fiber, carbon fiber, graphite powder, slag powder, high heat conduction ceramic particles and the like.
Most preferably, the reinforced heat conducting material is carbon fiber.
The invention also provides a preparation method of the encapsulated molten salt high-temperature heat storage concrete, which comprises the steps of weighing cement, encapsulated molten salt particles, a reinforced heat conduction material and auxiliary materials respectively, mixing the cement, the encapsulated molten salt particles, the reinforced heat conduction material and the auxiliary materials together, then adding water and a water reducing agent, uniformly stirring, and pouring and forming to obtain the encapsulated molten salt high-temperature heat storage concrete.
The packaged molten salt particles comprise large-particle-size packaged molten salt particles, medium-particle-size packaged molten salt particles and small-particle-size packaged molten salt particles, wherein the size of the large-particle-size packaged molten salt particles is 20-40 mm; the size of the medium-particle size packaging molten salt particles is 5-20 mm; the size of the small-particle-size packaging molten salt particles is 0.155-5 mm.
The auxiliary materials are fly ash and slag powder.
Further preferably, the encapsulation process of the molten salt particles is as follows:
weighing different molten salts according to the formula proportion, placing the molten salts in a stirrer to be stirred and mixed uniformly, heating and melting the mixed molten salt mixture, and naturally cooling; cooling, crushing, dissolving the powder in deionized water, drying, crushing and sieving to obtain molten salt particles with different particle size eutectic structures;
mixing and stirring a precursor tetrabutyl titanate and absolute ethyl alcohol according to a fixed proportion to obtain a precursor solution, adding high-temperature molten salt particles with different particle sizes into the precursor solution, and fully stirring and mixing the high-temperature molten salt particles and the precursor tetrabutyl titanate to form a mixed solution; adding a mixed solution of distilled water and glacial acetic acid into the mixed solution, carrying out hydrolysis reaction on a precursor in the mixed solution, carrying out hydrolysis reaction on tetrabutyl titanate to generate gel, coating the gel on high-temperature molten salt particles, putting the gel-coated high-temperature molten salt particles into a muffle furnace for sintering, and taking out the material after sintering is finished, and naturally cooling to obtain the packaged molten salt particles.
Classifying the packaged molten salt particles according to the particle size, and dividing the packaged molten salt particles into large-particle-size packaged molten salt particles, medium-particle-size packaged molten salt particles and small-particle-size packaged molten salt particles, wherein the size of the large-particle-size packaged molten salt particles is 20-40 mm; the medium particle size encapsulates 5-20 mm of fused salt particle size; the small-grain-size packaging molten salt has a grain size of 0.155-5 mm.
The invention has the beneficial effects that: the composite material is prepared by encapsulating molten salt particles and performing gel forming with cement, and the finally prepared material has the advantages of excellent mechanical property, large energy storage density, high thermal conductivity and stable high-temperature thermal property, and meets the service requirement of a sample under the actual heat storage working condition.
1) Compared with the traditional material in which the phase change and heat storage are completed by directly utilizing the fused salt material, the invention encapsulates the fused salt phase change material, and can solve the problems that the fused salt material has strong hygroscopicity and the solid-liquid phase is easy to leak. The shell can also isolate the contact between the fused salt phase change material and the concrete material, reduce the corrosivity and toxicity of ions formed after the fused salt is melted at high temperature to the concrete matrix, increase the high-temperature stability of the composite material and prolong the service life of the material.
2) The addition of carbon fibers can also enhance the heat conduction of the material.
3) By adding the encapsulated salt particles with different particle sizes into the concrete matrix as the coarse aggregate and the fine aggregate, the structural strength of the concrete-based composite material can be further improved, and the application range of the material is expanded.
4) The whole preparation process adopts a method of packaging firstly, mixing and then forming, the phase-change material container can be filled with the material firstly and then solidified in the application stage, the phase-change material container is better adapted, and the method has great application value in the application aspect of the heat storage device.
5) The invention has the advantages of low cost of raw materials, simple preparation method, suitability for large-scale production and wide application range.
Drawings
Fig. 1 is a structural diagram of a concrete-based molten salt composite phase-change heat storage material.
FIG. 2 is a flow chart of a concrete-based molten salt composite phase-change heat storage material.
FIG. 3 shows the thermal conductivity of the concrete-based molten salt composite phase-change heat storage material at different temperatures.
FIG. 4 shows different carbon fiber doping thermal conductivities of the concrete-based molten salt composite phase-change heat storage material.
Detailed Description
The embodiment of the invention provides a high-temperature composite phase-change heat storage material and a preparation method thereof, solves the problems of easy moisture absorption, easy leakage and poor high-temperature mechanical property of the existing molten salt phase-change heat storage material, and realizes a high-temperature heat storage material system taking cement as a base body. The following examples are intended to further illustrate the present invention, but they are not intended to limit or restrict the scope of the invention. It should be noted that the raw materials mentioned in the following examples are all available from the market, and the processing method of the materials which cannot be purchased directly is described in the examples.
Example 1
(1) Weighing sodium carbonate (52 parts by weight) according to the formula proportion: potassium carbonate (48 weight portions) is put into a stirrer to be stirred and mixed evenly, the rotating speed of the stirrer is 100r/s in the process, and the stirring time is 300s. And heating and melting the mixed molten salt mixture, heating to 850 ℃ at 30 ℃/min, uniformly stirring for 300s at constant temperature, and naturally cooling.
(2) And cooling, crushing, dissolving the powder in deionized water, drying, crushing and sieving to obtain high-temperature molten salt particles with different particle size eutectic structures.
(3) And (3) mixing and stirring a precursor tetrabutyl titanate and absolute ethyl alcohol according to a fixed proportion to obtain a precursor solution, adding the high-temperature molten salt particles with different particle sizes obtained in the step (2) into the precursor solution, stirring at the rotating speed of 300r/min for 1800s, and fully stirring and mixing the high-temperature molten salt particles and the precursor tetrabutyl titanate to form a mixed solution.
(4) And (4) adding a mixed solution of distilled water and glacial acetic acid (the pH value of the glacial acetic acid mixed solution is 2) into the mixed solution obtained in the step (3), so that a precursor in the mixed solution is subjected to hydrolysis reaction, and tetrabutyl titanate is subjected to hydrolysis reaction to generate gel to be coated on the high-temperature molten salt particles. Placing the gel-coated high-temperature molten salt particles into a muffle furnace, sintering at the temperature of 20 ℃/min to 450 ℃, sintering for 3h, taking out materials after sintering, and naturally cooling to obtain packaged molten salt particles, wherein the packaged molten salt particles are divided into large-particle-size packaged molten salt particles, medium-particle-size packaged molten salt particles and small-particle-size packaged molten salt particles according to particle sizes, and the size of the large-particle-size packaged molten salt particles is more than 20-40 mm; the size of the medium-particle size packaging molten salt particles is more than 5-20 mm; the size of the small-particle-size packaging molten salt particles is 0.155-5 mm.
(5) Respectively weighing 14.0 parts by weight of portland cement, 20.0 parts by weight of large-particle-size packaged molten salt particles, 20.0 parts by weight of medium-particle-size packaged molten salt particles, 27 parts by weight of small-particle-size packaged molten salt particles, 5 parts by weight of carbon fibers, 1.5 parts by weight of fly ash, 1.5 parts by weight of slag powder, 0.1 part by weight of organic fibers and 0.9 part by weight of steel fibers, adding the mixture into a vertical stirring cylinder, mixing for 10-15min, and then gradually and uniformly mixing the mixture for use.
(6) Weighing 7 parts of water and 0.6 part of water reducing agent, mixing, adding the mixed product into a stirrer, wet-mixing for 5min for use, pouring the product into a mold for gradual solidification, and demolding and maintaining to obtain the high-temperature heat storage composite material. Further testing the room temperature and high temperature strength of the composite material by using a universal testing machine; and testing the solid-liquid phase change behavior and the heat storage capacity of the composite material by using DSC, and testing the heat conduction performance of the composite material by using a laser heat conduction instrument. The thermal cycle test refers to placing the material in a heating and cooling box under normal pressure, raising the temperature to the service temperature of the material, and then cooling the material to room temperature, so as to perform heating/cooling cycle.
Example 2
In addition to the steps (1) and (5), the steps (2), (3) and (6) are the same as the corresponding steps in example 1.
(1) Weighing 21 parts by weight of lithium carbonate according to the formula proportion: 40 parts of sodium carbonate: 39 parts by weight of potassium carbonate is put into a stirrer to be stirred and mixed evenly, in the process, the rotating speed of the stirrer is 100r/s, and the stirring time is 300s. Heating and melting the mixed molten salt mixture, heating to 850 ℃ at 30 ℃/min, stirring uniformly at constant temperature for 300s, and naturally cooling.
(5) Respectively weighing 16.0 parts by weight of portland cement, 20.0 parts by weight of large-particle-size encapsulated molten salt particles, 23.0 parts by weight of medium-particle-size encapsulated molten salt particles, 29.0 parts by weight of small-particle-size encapsulated molten salt particles, 5 parts by weight of carbon fibers, 2.5 parts by weight of fly ash, 2 parts by weight of slag powder, 0.1 part by weight of organic fibers and 0.9 part by weight of steel fibers, adding the mixture into a vertical stirring cylinder, mixing for 10-15min, and then gradually and uniformly mixing the mixture for use.
Example 3
Except for the steps (1), (5) and (6), the steps (2) and (3) are the same as the corresponding steps in the example 1.
(1) Weighing sodium carbonate (52 parts by weight) according to the formula proportion: potassium carbonate (48 parts by weight) is put into a stirrer to be stirred and mixed evenly, the rotating speed of the stirrer in the process is 100r/s, and the stirring time is 300s. Heating and melting the mixed molten salt mixture, heating to 850 ℃ at the speed of 30 ℃/min, stirring uniformly for 300s at constant temperature, and naturally cooling.
(5) Respectively weighing 10.0 parts by weight of portland cement, 20.0 parts by weight of large-particle-size packaged molten salt particles, 20.0 parts by weight of medium-particle-size packaged molten salt particles, 35.0 parts by weight of small-particle-size packaged molten salt particles, 4 parts by weight of carbon fibers, 1.5 parts by weight of fly ash, 1 part by weight of slag powder, 0.1 part by weight of organic fibers and 0.9 part by weight of steel fibers, adding the mixture into a vertical stirring cylinder, mixing for 10-15min, and then gradually and uniformly mixing the mixture for use.
(6) Weighing 7 parts of water and 0.5 part of water reducing agent, mixing, adding the mixed product into a stirrer, wet-mixing for 5min for use, pouring the product into a mold for gradual solidification, and demolding and maintaining to obtain the high-temperature heat storage composite material.
The embodiment is the condition that the filling amount of the fused salt particles is the maximum, and the scheme can effectively improve the energy storage density of the composite material under the condition of ensuring the basic structural strength.
Example 4
Except for the steps (1), (5) and (6), the steps (2), (3) and (4) are the same as the corresponding steps in the example 1.
(1) Weighing sodium carbonate (52 parts by weight) according to the formula proportion: potassium carbonate (48 weight portions) is put into a stirrer to be stirred and mixed evenly, the rotating speed of the stirrer is 100r/s in the process, and the stirring time is 300s. Heating and melting the mixed molten salt mixture, heating to 850 ℃ at the speed of 30 ℃/min, stirring uniformly for 300s at constant temperature, and naturally cooling.
(5) Respectively weighing 18.0 parts by weight of Portland cement, 17.0 parts by weight of large-particle-size packaged molten salt particles, 18.0 parts by weight of medium-particle-size packaged molten salt particles, 30.0 parts by weight of small-particle-size packaged molten salt particles, 8 parts by weight of carbon fibers, 0.5 part by weight of fly ash, 0.1 part by weight of organic fibers and 0.9 part by weight of steel fibers, adding the mixture into a vertical stirring cylinder, mixing for 10-15min, and gradually and uniformly mixing the mixture for use.
(6) Weighing 7 parts by weight of water and 0.5 part by weight of water reducing agent, mixing, adding the mixed product into a stirrer, wet-mixing for 5min for use, pouring the product into a mold for gradual solidification, and demolding and maintaining to obtain the high-temperature heat storage composite material.
The embodiment is the condition that the cement consumption is the largest, and the scheme can effectively improve the structural strength of the composite material on the premise of ensuring the basic energy storage density.
Example 5
Unlike example 1, in step (6), the water reducing agent was used in an amount of 1 part by weight.
Example 6
Unlike example 1, in step (6), the amount of water was 12 parts by weight and the amount of water reducing agent was 0.1 part by weight.
Example 7
Unlike example 1, the cement was aluminate cement.
Example 8
Different from the example 1, in the step (1), lithium carbonate (52 parts by weight) is weighed according to the formula proportion: potassium carbonate (48 parts by weight) is put into a stirrer to be stirred and mixed evenly, the rotating speed of the stirrer in the process is 100r/s, and the stirring time is 300s. And heating and melting the mixed molten salt mixture, heating to 850 ℃ at 30 ℃/min, uniformly stirring for 300s at constant temperature, and naturally cooling.
Example 9
Different from the example 1, in the step (1), sodium phosphate (52 parts by weight) is weighed according to the formula proportion: potassium nitrate (48 weight portions) is put into a stirrer to be stirred and mixed evenly, the rotating speed of the stirrer in the process is 100r/s, and the stirring time is 300s. Heating and melting the mixed molten salt mixture, heating to 850 ℃ at the speed of 30 ℃/min, stirring uniformly for 300s at constant temperature, and naturally cooling.
Example 10
Unlike example 1, the carbon fibers were replaced with graphite powder.
Example 11
Different from the embodiment 1, in the step (3), the precursor zirconium n-propoxide and isopropanol are mixed and stirred according to a fixed proportion to obtain a precursor solution, so that the zirconia ceramic-encapsulated molten salt particles are prepared.
Comparative example 1
Except for the steps (1), (5) and (6), the steps (2), (3) and (4) are the same as the corresponding steps in the example 1.
(1) Weighing 52 parts by weight of sodium carbonate according to the formula proportion: 48 parts by weight of potassium carbonate is put into a stirrer to be stirred and mixed uniformly, the rotating speed of the stirrer in the process is 100r/s, and the stirring time is 300s. Heating and melting the mixed molten salt mixture, heating to 850 ℃ at the speed of 30 ℃/min, stirring uniformly for 300s at constant temperature, and naturally cooling.
(5) Respectively weighing 12.0 parts by weight of Portland cement, 12.0 parts by weight of large-particle-size packaged molten salt particles, 16.0 parts by weight of medium-particle-size packaged molten salt particles, 40.6 parts by weight of small-particle-size packaged molten salt particles, 3.5 parts by weight of fly ash, 2.5 parts by weight of slag powder, 0.1 part by weight of organic fibers and 4.9 parts by weight of steel fibers, adding the mixture into a vertical stirring cylinder, and mixing for 10-15min, and then gradually uniformly mixing the mixture for use.
(6) Weighing 8.0 parts of water and 0.4 part of water reducing agent, mixing, adding the mixed product into a stirrer, wet-mixing for 5min for use, pouring the product into a mold for gradual solidification, and demolding and maintaining to obtain the high-temperature heat storage composite material.
Comparative example 2
(1) Weighing 52 parts by weight of sodium carbonate according to the formula proportion: 48 parts by weight of potassium carbonate is put into a stirrer to be stirred and mixed uniformly, the rotating speed of the stirrer in the process is 100r/s, and the stirring time is 300s. Heating and melting the mixed molten salt mixture, heating to 850 ℃ at the speed of 30 ℃/min, stirring uniformly for 300s at constant temperature, and naturally cooling.
(2) And cooling, crushing, dissolving the powder in deionized water, drying, crushing and sieving to obtain high-temperature molten salt particles with different particle size eutectic structures. According to the particle size of the high-temperature molten salt, the size of the fused salt particles with large particle size is 20-40 mm; the size of the fused salt particles with medium particle size is 5-20 mm; the size of the small-particle size fused salt particles is 0.155-5 mm.
(3) Respectively weighing 12.0 parts by weight of portland cement, 18.0 parts by weight of large-particle size molten salt particles, 20.0 parts by weight of medium-particle size molten salt particles, 29.0 parts by weight of small-particle size molten salt particles, 5 parts by weight of carbon fibers, 3.5 parts by weight of fly ash, 2.5 parts by weight of slag powder, 0.1 part by weight of organic fibers and 0.9 part by weight of steel fibers, adding the mixture into a vertical stirring cylinder, mixing for 10-15min, and gradually mixing uniformly.
(4) Weighing 8.5 parts of water and 0.5 part of water reducing agent, mixing, adding the mixed product into a stirrer, wet-mixing for 5min for use, pouring the product into a mold for gradual solidification, and demolding and maintaining to obtain the high-temperature heat storage composite material.
Comparative example 3
(1) Weighing 52 parts by weight of sodium carbonate according to the formula proportion: 48 parts by weight of potassium carbonate is put into a stirrer to be stirred and mixed uniformly, the rotating speed of the stirrer in the process is 100r/s, and the stirring time is 300s. Heating and melting the mixed molten salt mixture, heating to 850 ℃ at the speed of 30 ℃/min, stirring uniformly for 300s at constant temperature, and naturally cooling.
(2) Cooling, pulverizing, dissolving in deionized water, drying, crushing and sieving to obtain eutectic high-temperature molten salt particles.
(3) Respectively weighing 15.0 parts by weight of portland cement, 69 parts by weight of high-temperature molten salt particles, 3.5 parts by weight of fly ash, 2.5 parts by weight of slag powder, 0.1 part by weight of organic fibers and 4.9 parts by weight of steel fibers, adding the mixture into a vertical stirring cylinder, mixing for 10-15min, and gradually and uniformly mixing the mixture for use.
(4) Weighing 7.5 parts of water and 0.5 part of water reducing agent, mixing, adding the mixed product into a stirrer, wet-mixing for 5min for use, pouring the product into a mold for gradual solidification, and demolding and maintaining to obtain the high-temperature heat storage composite material.
TABLE 1 physical Properties of concrete-based fused salt composite phase-change heat storage Material
Figure BDA0003887083910000091
As can be seen from table 1, in the analysis of the examples and comparative examples, the composite energy storage density gradually increased with the increase of the content of the molten salt added, but the structural strength decreased with the increase of the content of the molten salt. The embodiment 1 has better structural strength and energy storage density, the thermal conductivity is 5.46W/m.K, and the thermal cycle stability is excellent; in the embodiment 2, the energy storage density is improved by changing the variety of the molten salt, the structural strength is slightly reduced, the thermal conductivity is 5.23W/m.K, and the thermal cycle stability is excellent; in the comparative example 1, carbon fibers are not added into the composite material, so that the thermal conductivity of the material is low, the structural strength of the material is reduced due to improper grain size grading, the fracture resistance of the composite material is obviously reduced, and the composite material cracks after 80 thermal cycle test; in the comparative example 2, the molten salt is not encapsulated, the structural strength of the composite material is reduced, and the thermal cycle stability is deteriorated and cracks appear after 5 thermal cycle tests; in comparative example 3, no molten salt was encapsulated, the thermal cycle stability deteriorated and cracked after 5 thermal cycle tests, the structural strength of the composite material was reduced, and meanwhile, the particle size was not classified in the material, and the comprehensive properties of the composite material were poor. Therefore, the specific packaging molten salt concrete-based high-temperature heat storage composite material can be prepared by selecting different proportions according to different use scene requirements.
The above-described embodiments are only intended to illustrate the preferred embodiments of the present invention, and not to limit the scope of the present invention, and various modifications and improvements made to the technical solution of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims (10)

1. The utility model provides a package fused salt high temperature heat storage concrete which characterized in that, cement: 10-18 parts by weight of molten salt particles: 65-75 parts by weight of reinforced heat conducting material: 4-8 parts by weight of water: 7-12 parts by weight of water reducing agent: 0.1-1 part by weight, encapsulating the fused salt particles by a ceramic material to form a ceramic shell, then adding water into the encapsulated fused salt particles, cement and a reinforced heat conduction material, mixing and stirring, and finally pouring and forming to obtain the encapsulated fused salt high-temperature heat storage concrete.
2. The encapsulated molten salt high-temperature heat storage concrete as claimed in claim 1, the packaged molten salt particles comprise large-particle-size packaged molten salt particles, medium-particle-size packaged molten salt particles and small-particle-size packaged molten salt particles, wherein the size of the large-particle-size packaged molten salt particles is more than 20-40 mm; the size of the medium-grain size packaging fused salt is more than 5-20 mm; the small-grain-size packaging molten salt has a grain size of 0.155-5 mm.
3. The encapsulated molten salt high-temperature heat storage concrete as claimed in claim 1, wherein the cement is one or more of sulphoaluminate cement, portland cement, aluminate cement, low-calcium aluminate cement, calcium magnesium aluminate cement, ferro-aluminate cement, fluoroaluminate cement and phosphate cement. Further, the core material of the encapsulating molten salt particle described herein is a high temperature molten salt.
4. The packaged molten salt high-temperature heat storage concrete as claimed in claim 1, wherein molten salt in the molten salt particles is one or more of alkali metal or alkaline earth metal and halide, silicate, carbonate, nitrate and phosphate.
5. The encapsulated molten salt high-temperature heat storage concrete as claimed in claim 1, wherein the molten salt in the molten salt particles is eutectic molten salt of lithium carbonate, sodium carbonate and sodium carbonate.
6. The encapsulated molten salt high temperature heat storage concrete of claim 1, wherein the ceramic shell is a high thermal conductivity, corrosion resistant ceramic material.
7. The encapsulated molten salt high-temperature heat storage concrete as claimed in claim 1, the reinforced heat conduction material is any one of steel fiber, carbon fiber, graphite powder, slag powder and high heat conduction ceramic particles.
8. The preparation method of the encapsulated molten salt high-temperature heat storage concrete as claimed in claim 1, characterized by weighing cement, encapsulated molten salt particles, reinforced heat conducting material and auxiliary material respectively, mixing together, then adding water and water reducing agent, stirring uniformly, and pouring and molding to obtain the encapsulated molten salt high-temperature heat storage concrete.
9. The preparation method of the encapsulated molten salt high-temperature heat storage concrete as claimed in claim 8, wherein the encapsulated molten salt particles comprise large-particle size encapsulated molten salt particles, medium-particle size encapsulated molten salt particles and small-particle size encapsulated molten salt particles, wherein the large-particle size encapsulated molten salt particles are 20-40 mm in size; the medium particle size encapsulates 5-20 mm of fused salt particle size; the size of the small-particle-size packaging molten salt particles is 0.155-5 mm.
10. The preparation method of the encapsulated molten salt high-temperature heat storage concrete as claimed in claim 8, the method is characterized in that the encapsulation process of the fused salt particles is as follows:
weighing different molten salts according to the formula proportion, placing the molten salts in a stirrer to be stirred and mixed uniformly, heating and melting the mixed molten salt mixture, and naturally cooling; cooling, crushing, dissolving the powder in deionized water, drying, crushing and sieving to obtain molten salt particles with different particle size eutectic structures;
mixing and stirring a precursor tetrabutyl titanate and absolute ethyl alcohol according to a fixed proportion to obtain a precursor solution, adding high-temperature molten salt particles with different particle sizes into the precursor solution, and fully stirring and mixing the high-temperature molten salt particles and the precursor tetrabutyl titanate to form a mixed solution; adding a mixed solution of distilled water and glacial acetic acid into the mixed solution, carrying out hydrolysis reaction on a precursor in the mixed solution, carrying out hydrolysis reaction to generate gel, coating the gel on the high-temperature molten salt particles, putting the gel-coated high-temperature molten salt particles into a muffle furnace for sintering, taking out the material after sintering, and naturally cooling to obtain the packaged molten salt particles.
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008308607A (en) * 2007-06-15 2008-12-25 Kao Corp Method for manufacturing heat storage material
CN104386981A (en) * 2014-10-24 2015-03-04 马鞍山市博浪热能科技有限公司 Concrete materials having functions of heat conduction and heat storage, and preparation method thereof
CN109135683A (en) * 2018-08-22 2019-01-04 北京科技大学 A method of preparing fused salt-ceramics phase-change heat-storage material

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008308607A (en) * 2007-06-15 2008-12-25 Kao Corp Method for manufacturing heat storage material
CN104386981A (en) * 2014-10-24 2015-03-04 马鞍山市博浪热能科技有限公司 Concrete materials having functions of heat conduction and heat storage, and preparation method thereof
CN109135683A (en) * 2018-08-22 2019-01-04 北京科技大学 A method of preparing fused salt-ceramics phase-change heat-storage material

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