Modifier, modified thermochemical heat storage material and module, and preparation methods therefor

Abstract

Provided in the present invention are a modifier, a modified thermochemical heat storage material and a module, and preparation methods therefor. The modifier for a thermochemical heat storage material has a general formula of MySiOz, wherein M is one or more of Co, Zn, Ni, Zr, Cu, Cr and Mg, and y and z are real numbers. When the modifier is added to a thermochemical heat storage material, during the process of forming a modified heat storage material, no by-product is generated, and the growth of crystals on the surface of the thermochemical heat storage material can be inhibited while the heat storage performance of the thermochemical heat storage material is ensured, thereby improving the anti-sintering capability of the thermochemical heat storage material and also enhancing the stability of the thermochemical heat storage material during long-term cycling in a high-temperature environment.

Description

Modifier, modified thermochemical heat storage material, module and preparation method thereof Technical Field

[0001] The present invention relates to the field of energy storage, and in particular to a modifier, a modified thermochemical heat storage material, a module and a preparation method thereof. Background Art

[0002] Thermochemical heat storage uses reversible thermochemical reactions to store and release thermal energy. The energy storage density of thermochemical heat storage materials is usually 0.5 to 3 GJ / m 3 , which is about 810 times that of sensible heat materials and more than twice that of latent heat materials, and has low heat loss during long-term storage. Therefore, it is considered to be one of the most promising heat storage methods in the future.

[0003] High-temperature thermochemical energy storage technology based on metal oxides (such as cobalt, manganese, copper, and iron) stores and releases energy through reduction / oxidation reactions between metal oxides of different valence states. The heat storage temperature can reach above 800°C, and within a small temperature range, the energy storage density can reach 300 to 1000 kJ / kg. However, problems such as unstable performance and short cycle life during long-term reactions have seriously restricted its development and application.

[0004] Summary of the Invention

[0005] To address the above issues, the present invention provides a modifier, a modified thermochemical heat storage material, a module, and a preparation method thereof. The modifier is added to the thermochemical heat storage material. During the formation of the modified heat storage material, no by-products are generated. While ensuring the heat storage performance of the thermochemical heat storage material, the growth of crystals on the surface of the thermochemical heat storage material can be inhibited, thereby improving the thermochemical heat storage material's anti-sintering ability and its stability in long-term high-temperature circulation.

[0006] The first aspect of the present invention provides a thermochemical heat storage material modifier, the general formula of the thermochemical heat storage material modifier is M y SiO z ; Wherein, M = one or more of Co, Zn, Ni, Zr, Cu, Cr, Mg, and y and z are real numbers.

[0007] According to this technical solution, new chemical bonds are generated between the thermochemical heat storage material modifier and the thermochemical heat storage material due to the interaction of charges, so that the thermochemical heat storage material modifier can be stably attached to the surface of the thermochemical heat storage material by relying on the pinning effect, inhibiting the growth of grains on the surface of the thermochemical heat storage material, avoiding large-area sintering of the thermochemical heat storage material due to excessive grain growth, and improving the anti-sintering ability and cyclic stability of the thermochemical heat storage material.

[0008] In an optional technical solution of the present invention, the particle size of the thermochemical heat storage material modifier is not greater than 2 μm.

[0009] According to this technical solution, compared with the particle size of the thermochemical heat storage material, the particle size of the thermochemical heat storage material modifier is no more than 2 μm, and the particle size is smaller; the larger specific surface area to volume ratio of the thermochemical heat storage material modifier is conducive to its adsorption on the surface of the thermochemical heat storage material.

[0010] A second aspect of the present invention provides a method for preparing a thermochemical heat storage material modifier, comprising the following steps: step S11: providing a metal oxide corresponding to M and SiO2, wherein M also includes Mn, and the metal oxide corresponding to Mn is manganese tetraoxide; step S12: fully mixing the metal oxide corresponding to M and SiO2 in proportion to obtain a first precursor; step S13: calcining the first precursor obtained in step S12, taking it out, grinding it into powder, and obtaining a thermochemical heat storage material modifier.

[0011] According to this technical solution, the solid-phase synthesis method is used to prepare the thermochemical heat storage material modifier, which has the advantages of low cost, large output, simple equipment and preparation process, and high production efficiency.

[0012] In an optional technical solution of the present invention, the calcination temperature of the first precursor is 700-1100° C., and the calcination time is 0.5-8 hours.

[0013] According to this technical solution, the metal oxide corresponding to M undergoes a chemical reaction with SiO2 during calcination. By controlling the calcination temperature and time, the chemical reaction rate can be increased, resulting in a single modifier silicate crystal. The combination of the modifier and the thermochemical heat storage material inhibits grain growth on the surface of the material at high temperatures, improving the material's resistance to sintering.

[0014] The third aspect of the present invention provides a method for preparing the above-mentioned thermochemical heat storage material modifier, which is a coprecipitation method. The coprecipitation method comprises the following steps:

[0015] Step S21: dispersing the silicon source in deionized water to form a homogeneous solution, and adding alkali to the homogeneous solution to adjust the pH value of the suspension to alkaline;

[0016] Step S22: adding the metal salt corresponding to M to the homogeneous solution obtained in step S21 to obtain a precipitate and a supernatant;

[0017] Step S23: filtering and separating the supernatant and the precipitate obtained in step S22, washing the filtered residue with deionized water and ethanol, and drying the washed residue at room temperature to obtain a thermochemical heat storage material modifier.

[0018] According to this technical solution, the preparation of the thermochemical energy storage material by the coprecipitation method can achieve the high-purity separation of the modifier of the thermochemical energy storage material, with high selectivity and applicability. By adjusting the pH of the suspension to alkaline with the corresponding solid base in step S21, the hydrolysis of the silicon source (such as sodium silicate) can be avoided, and at the same time, the introduction of new impurities can be avoided, improving the purity of the modifier of the thermochemical energy storage material.

[0019] The fourth aspect of the present invention provides a modified thermochemical energy storage material, including: a main energy storage material with a general formula: (Mn 1-x Fe x )2O3; the above-mentioned modifier of the thermochemical energy storage material; the general formula of the modified chemical energy storage material is (Mn 1-x Fe x )2O3·nM y SiO z , 0.1 < x < 0.4, 0 < n < 0.4, and the modifier of the thermochemical energy storage material is attached to the surface of the main energy storage material.

[0020] According to this technical solution, for different types of metal oxide energy storage materials, the suitable modifiers are different. For the manganese-iron composite metal oxide energy storage material, by using the silicate corresponding to the metal material M and controlling the value range of n, the grain growth on the surface of the manganese-iron composite metal oxide energy storage material can be better inhibited, ensuring that the modified thermochemical energy storage material has good energy storage performance, better anti-sintering ability and good cycling performance.

[0021] In an optional technical solution of the present invention, the value range of n is 0.01 - 0.05.

[0022] According to this technical solution, by controlling the molar ratio n of the modifier of the thermochemical energy storage material to the main energy storage material within a specified range, the attachment amount of the modifier of the thermochemical energy storage material on the surface of the main energy storage material can be ensured within a specified range (that is, the attachment amount is neither too much nor too little), ensuring the energy storage performance of the thermochemical energy storage modified material while inhibiting the grain growth on the surface of the main energy storage material and saving the dosage of the modifier of the thermochemical energy storage material.

[0023] The fifth aspect of the present invention provides a preparation method of the above-mentioned modified thermochemical energy storage material, including the following steps: Step S31: Provide a manganese-iron composite metal oxide energy storage material; Step S32: Provide the above-mentioned modifier of the thermochemical energy storage material; Step S33: Mix the manganese-iron composite metal oxide energy storage material obtained in step S32 with the modifier of the thermochemical energy storage material in step S33 according to a specified ratio to obtain a modified manganese-iron composite metal oxide energy storage material.

[0024] According to this technical solution, the solid-phase synthesis method is used to prepare the modified thermochemical heat storage material, which has the advantages of low cost, large output, simple equipment and preparation process, and high production efficiency.

[0025] In an optional technical solution of the present invention, the preparation method of the manganese-iron composite metal oxide heat storage material includes: S41: fully mixing manganese-manganese tetroxide and ferric oxide to obtain a second precursor; S42: calcining the second precursor at high temperature, taking it out, and grinding it into powder to obtain the manganese-iron composite metal oxide heat storage material.

[0026] According to this technical solution, the solid interface between manganese manganese tetroxide and ferric oxide undergoes contact, reaction, nucleation, and crystal growth reaction to finally obtain a manganese-iron composite metal oxide heat storage material. This preparation method has low cost, high output, simple equipment and preparation process, and high production efficiency.

[0027] Manganese-manganese oxide is used as a manganese source and a composite manganese-iron metal oxide is prepared by a high-temperature solid-phase synthesis method. Under the same conditions, manganese-manganese oxide has a better synthesis effect than manganese dioxide. Since the principle of high-temperature solid-phase synthesis is to place the mixed raw materials under high temperature conditions (usually between 600°C and 1000°C), at this temperature, the solid raw materials undergo a chemical reaction, and the metal ions in the raw materials begin to migrate and rearrange to form a new crystal structure. The crystal structure of manganese dioxide corresponds to the orthorhombic crystal system, and its lattice stability is high, and the lattice structure is not easy to destroy. Therefore, the composite effect with ferric oxide in the synthesis stage is not good, which affects the subsequent redox reaction. In contrast, manganese-manganese oxide is composed of Mn 2+ and Mn 3+ The ion composition and crystal structure are complex, so under certain conditions it is more likely to undergo structural changes, and the chemical reaction with ferric oxide is more complete, thus obtaining a more ideal manganese-iron composite metal oxide heat storage material.

[0028] The present invention provides a method for preparing a modified thermochemical heat storage module, comprising the following steps:

[0029] Step S51: Mn3O4 and Fe2O3 powders are put into a mixer in a molar ratio of 8:3 to 1:1 and mixed evenly. The evenly mixed Mn3O4 and Fe2O3 powders are then calcined to obtain a main heat storage material. The calcined main heat storage material is cooled, ground, and screened to a desired particle size.

[0030] Step S52: Mn3O4 and SiO2 powders are put into a mixer in a molar ratio of 1:6 to 7:3 and mixed evenly. The evenly mixed Mn3O4 and SiO2 powders are then calcined to obtain a thermochemical heat storage material modifier. The calcined thermochemical heat storage material modifier is cooled, ground, and screened to a desired particle size.

[0031] Step S53: uniformly mixing the main heat storage material obtained in step S51 and the thermochemical heat storage material modifier obtained in step S52 in a prescribed ratio to obtain a modified thermochemical heat storage material;

[0032] Step S54: providing an adhesive and uniformly mixing the adhesive with the modified thermochemical heat storage material in step S53;

[0033] Step S55: Extruding the modified thermochemical heat storage material and the binder uniformly mixed in step S52 into a thermochemical heat storage module;

[0034] Step S56: Exchanging the waste heat generated by the calcination in step S51 and step S52 with the heat exchanger. The heat exchanger absorbs the heat generated by the calcination and transfers it to the thermochemical heat storage module in step S55, so that the temperature of the thermochemical heat storage module is raised to a specified temperature.

[0035] Step S57: calcining the thermochemical heat storage module obtained in step S56. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] FIG1 is a SEM image of the modifier S1 according to an embodiment of the present invention.

[0037] FIG2 is a SEM image of the modifier S2 according to an embodiment of the present invention.

[0038] FIG3 is a SEM image of the modifier S3 according to an embodiment of the present invention.

[0039] FIG4 is an X-ray diffraction spectrum of the modifier S1 according to an embodiment of the present invention.

[0040] FIG5 is an X-ray diffraction spectrum of the modifier S2 according to an embodiment of the present invention.

[0041] FIG6 is an X-ray diffraction spectrum of the modifier S3 according to an embodiment of the present invention.

[0042] FIG7 is a thermogravimetric analysis graph of sample G1 after 100 cycles in an embodiment of the present invention.

[0043] FIG8 is a thermogravimetric analysis graph of sample G2 after 100 cycles in an embodiment of the present invention.

[0044] FIG9 is a thermogravimetric analysis graph of sample G3 after 100 cycles according to an embodiment of the present invention.

[0045] FIG10 is a thermogravimetric analysis graph of sample G4 after 100 cycles according to an embodiment of the present invention.

[0046] FIG11 is a schematic flow chart of a method for preparing a modified thermochemical heat storage module according to an embodiment of the present invention.

[0047] Reference numerals:

[0048] a first mixer 11 ; a first calcining furnace 12 ; a first heat exchanger 13 ; a first grinder 14 ; a first filter 15 ; a second mixer 21 ; a second calcining furnace 22 ; a second heat exchanger 23 ; a second grinder 24 ; a second filter 25 ; a third mixer 31 ; an extruder 32 ; a third heat exchanger 33 ; a third calcining furnace 34 ; and a storage tank 35 . DETAILED DESCRIPTION

[0049] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0050] 1. Material Preparation

[0051] 1.1 Preparation of thermochemical heat storage material modifier

[0052] 1.1.1 Solid-phase synthesis

[0053] Step S11: providing a metal oxide corresponding to M and SiO2, where M = one or more of Co, Zn, Ni, Zr, Cu, Cr, and Mg, y and z are real numbers, M also includes Mn, and the metal oxide corresponding to Mn is ferroferric oxide;

[0054] Step S12: fully mixing the metal oxide corresponding to M with SiO2 in proportion to obtain a first precursor;

[0055] Step S13: calcining the first precursor obtained in step S12, taking it out, and grinding it into powder to obtain a thermochemical heat storage material modifier.

[0056] Specifically, for a manganese silicate modifier, 0.01 mol of manganese tetraoxide and 0.03 mol of silicon dioxide were placed in a ball mill and mixed for 30 minutes to obtain a first precursor. This precursor was then calcined in a muffle furnace at 1100°C for 4 hours. After cooling, the mixture was ground and sieved to obtain a powder with a particle size of less than 2 μm, resulting in manganese silicate modifier S3.

[0057] In a preferred embodiment of the present invention, the particle size of the thermochemical heat storage material modifier is 10nm-2μm, more preferably, the particle size of the thermochemical heat storage material modifier is 60-400nm. In some embodiments, the particle size of the thermochemical heat storage material modifier can also be 600-800nm, 900nm, 1500nm, 1800nm, etc.

[0058] It should be noted that technicians can adjust the calcination temperature to 700-1100° C. and the calcination time to 0.5-8 hours as needed, and are not limited to the examples given in this embodiment.

[0059] 1.1.2 Coprecipitation method

[0060] Dissolve 0.05 mol of Na2SiO3·9H2O in deionized water to obtain a uniform solution, and add solid NaOH (ammonia water can also be added) to adjust the pH value of the uniform solution to 8-10. Quickly add 0.1 mol of M(NO3)m (M=one or more of Co, Zn, Ni, Zr, Cu, Cr, Mg) to the uniform solution to form a precipitate and continue stirring for 2 hours (the stirring temperature is preferably 25-40°C, and the stirring time is preferably 0.5-2 hours). Filter to obtain a filter residue, wash the filter residue with deionized water and ethanol multiple times, and dry it at room temperature for 12 hours (the drying time can be 6-24 hours, and technicians can adjust it according to actual conditions) to obtain a silicate modified additive powder M y SiO z .

[0061] Select nitrate M (NO3) m As a source of metal cations, nitrate ions have a stronger polarity to water due to differences in the crystal structure and chemical bonding properties of nitrates and chlorides. This results in a higher solubility of nitrates in water, which facilitates a more complete reaction. Furthermore, chlorides are generally more toxic than nitrates, especially to chlorides of some metal ions. Therefore, nitrates are a safer and more reliable source of metal cations. Adjusting the pH of the solution with NaOH not only avoids the introduction of new impurities but also prevents the hydrolysis of sodium silicate.

[0062] The thermochemical heat storage material prepared by the coprecipitation method is an amorphous modifier. The amorphous modifier enhances its adsorption capacity on the surface of the main heat storage material. At the same time, the disordered atomic arrangement of the amorphous material also provides more compatibility for modifying the electronic structure of the thermochemical heat storage material.

[0063] 1.2 Preparation of thermochemical heat storage materials

[0064] Weigh 0.8 mol of reagent-grade Mn3O4 and 0.3 mol of reagent-grade Fe2O3 respectively, place them in a ball mill, and ball mill for 30 minutes to fully mix them. The mixing time is preferably 0.5-2 hours. Then place the mixture in a muffle furnace and calcine it at 1000℃ for 8 hours. After cooling, take it out and grind it. After screening, a black powder of the main heat storage material is obtained: (Mn 0.8 Fe 0.2 )2O3.

[0065] First, Mn3O4 and Fe2O3 are uniformly mixed. The mixing method can be a ball mill, a blender or a rotary kiln, etc., which is not limited here. Then, the uniformly mixed powders are compounded at high temperature. Under high temperature conditions, the uniformly contacted solid interfaces undergo contact, reaction, nucleation, and crystal growth reactions to finally obtain the main heat storage material, manganese-iron composite metal oxide. This preparation method has low cost, high output, simple equipment and preparation process, and high production efficiency.

[0066] Mn3O4 is used as a manganese source, and a composite manganese-iron metal oxide is prepared by a high-temperature solid-phase synthesis method. Under the same conditions, Mn3O4 has a better synthesis effect than Mn2O3. Since the principle of the high-temperature solid-phase synthesis method is to place the mixed raw materials under high temperature conditions (usually between 600°C and 1000°C), at this temperature, the solid raw materials undergo a chemical reaction. At this temperature, the metal ions in the raw materials begin to migrate and rearrange to form a new crystal structure. The crystal structure of manganese trioxide corresponds to the orthorhombic crystal system, and its lattice stability is high, and the lattice structure is not easily destroyed. Therefore, the composite effect with Fe2O3 in the synthesis stage is not good, which affects the subsequent redox reaction. In contrast, Mn3O4 is composed of Mn 2+ and Mn 3+ The ion composition and crystal structure are complex, so under certain conditions it is more likely to undergo structural changes, and the chemical reaction with Fe2O3 is more complete, thus obtaining a manganese-iron composite metal oxide heat storage material with better performance.

[0067] 1.3 Preparation of modified thermochemical heat storage materials

[0068] 4.95 g of manganese-iron composite metal oxide and 0.05 g of thermochemical heat storage material modifier were placed in a ball mill, ball milled and mixed for 30 minutes, and then taken out to obtain a modified manganese-iron composite metal oxide heat storage material.

[0069] The following specific embodiments can be obtained according to the type and preparation method of the selected thermochemical heat storage material modifier:

[0070] Amorphous cobalt silicate CoSiO3 synthesized by coprecipitation method was selected as the thermochemical heat storage material modifier S1, and the doping mass ratio was 0.01. The modified manganese-iron composite metal oxide heat storage material G1 obtained was (Mn 0.8 Fe 0.2 )2O3·0.01CoSiO3.

[0071] Amorphous copper silicate CuSiO3 synthesized by coprecipitation method was selected as the thermochemical heat storage material modifier S2, and the doping mass ratio was 0.01. The modified manganese-iron composite metal oxide heat storage material G2 obtained was (Mn 0.8 Fe 0.2 )2O3·0.01CuSiO3.

[0072] Manganese silicate MnSiO3 synthesized by solid phase synthesis was selected as the thermochemical heat storage material modifier S3, and the doping mass ratio was 0.01. The modified manganese iron composite metal oxide heat storage material G3 obtained was (Mn 0.8 Fe 0.2 )2O3·0.01MnSiO3(sp).

[0073] Thermochemical heat storage material G4 (Mn 0.8 Fe 0.2 )2O3.

[0074] In this embodiment, during the synthesis process of the uniformly mixed powdered main thermal storage material and amorphous silicate, the amorphous silicate additive can evenly and firmly adhere to the surface of the main thermal storage material. Because the particle size of the amorphous silicate additive is no larger than 2 μm, it has a smaller particle size than the manganese-iron composite metal oxide thermal storage material prepared by the solid-phase synthesis method (the ratio of the particle size of the amorphous silicate modifier to the particle size of the main thermal storage material particles is 0.001 to 0.25, preferably, the ratio of the two particle sizes is in the range of 0.1 to 0.25). At the same time, the larger surface area to volume ratio facilitates its adsorption on the thermal storage material surface. This is because the high specific surface area of ​​the small particles makes the charge effect more significant, resulting in a stable interaction with the main thermal storage material, preventing the agglomeration of large particles of the main thermal storage material during the redox process, thereby effectively improving the sintering phenomenon that occurs in the main thermal storage material under high-temperature reaction conditions, resulting in a long-life and high-performance modified manganese-iron composite metal oxide thermal storage material.

[0075] 2. Material Characterization

[0076] The following experiment was used to characterize the modified manganese-iron composite metal oxide heat storage material prepared by the above preparation method.

[0077] High-temperature calcination was performed using a KSL-1200X box-type furnace from Hefei Kejing Co., Ltd., with a heating rate of 1-10°C / min. Scanning electron microscopy (SEM) was performed using a Zeiss Sigma 300 field-emission scanning electron microscope (FESEM) from Germany. X-ray diffraction (XRD) analysis was performed using an Xpert Powder X-ray diffractometer from PANalytical (Netherlands). Thermogravimetric analysis (TG) was performed using a TGA / DSC3+ simultaneous thermal analyzer from Mettler (Switzerland).

[0078] 2.1 Scanning electron microscopy

[0079] Figures 1, 2, and 3 are SEM images of the modifying additives S1-S3, respectively, according to this embodiment. As shown in Figures 1 and 2, the amorphous silicate modifier has a relatively small particle size and a very loose particle structure. Therefore, compared to the bulk structure of the crystalline modifier shown in Figure 3, the amorphous silicate additive can better adhere to the surface of the manganese-iron composite metal oxide thermal storage material, thereby forming a barrier between the manganese-iron composite metal oxide particles, preventing agglomeration between the manganese-iron composite metal oxide particles, and improving the cyclic heat storage performance of the modified manganese-iron composite metal oxide thermal storage material.

[0080] 2.2 X-ray diffraction

[0081] Figures 4 and 5 correspond to the X-ray diffraction patterns of the modifiers S1-S2 in this embodiment, respectively. The horizontal axis is twice the incident angle of the X-ray, and the vertical axis is the intensity after diffraction. It can be seen from Figures 4 and 5 that the modifiers S1 and S2 have typical amorphous diffraction peaks, indicating that the samples are amorphous substances. At the same time, there are also characteristic peaks of the corresponding silicates in the figure, indicating that the corresponding amorphous silicate modified additives are successfully prepared using the embodiment method. Figure 6 corresponds to the manganese silicate additive S3 prepared by the solid-phase synthesis method, which crystallizes well at high temperature to form a clear and strong silicate diffraction peak, indicating that the silicate is successfully synthesized at high temperature using the corresponding metal oxide and silicon oxide.

[0082] 2.3 Thermogravimetric analysis

[0083] The following experiment was used to determine the heat storage performance of the modified manganese-iron composite metal oxide heat storage material: The modified manganese-iron composite metal oxide heat storage materials (samples G1-G3) and the comparative sample manganese-iron composite metal oxide heat storage material G4 were placed on a thermochemical experimental platform for thermal cycling experiments.

[0084] The temperature control program was as follows: first, heating from room temperature to 700°C, then from 700°C to 1000°C, holding for 30 minutes, and then cooling from 1000°C to 700°C, holding for 30 minutes; the heating and cooling rates were both 10°C / min, and the air flow rate was 1 L / min (pO2 = 0.21). The process of heating to 1000°C and then cooling to 700°C was considered one cycle. After 100 consecutive cycles, heating was stopped. After the equipment had completely cooled, 8-11 mg of the modified manganese-iron composite metal oxide thermal storage material sample was taken for thermogravimetric analysis. The heating rate was 20°C / min, the cooling rate was 10°C / min, and the air flow rate was 50 ml / min (pO2 = 0.21).

[0085] The temperature control program for the thermogravimetric analysis of samples G1, G2, G3, and G4 was as follows: first, heat from 50°C to 1000°C and keep warm for 10 minutes; then cool from 1000°C to 700°C.

[0086] The experimental results are shown in Table 1 and Figures 7-10. Table 1 shows the thermogravimetric analysis results of samples G1-G4 after thermal cycling experiments, and Figures 7-10 are the thermogravimetric analysis curves of samples G1-G4 after cycling.

[0087] Table 1

[0088] After multiple cycles of reaction, the heat storage material is prone to crystal growth, resulting in coarsening and densification of the microstructure. In addition, sintering leads to the agglomeration of microparticles, a decrease in the specific surface area of ​​the material, difficulty in oxygen mass transfer, and a serious deterioration in the reaction characteristics, which is an important factor affecting the decline in the cyclic stability of thermochemical heat storage materials. Thermogravimetric analysis results show that compared with the reoxidation rate (less than 40%) and reduction rate (90.13%) of thermochemical heat storage materials without modifiers, the reoxidation rate and re-reduction rate of thermochemical heat storage materials modified with crystalline or amorphous thermochemical heat storage materials have been significantly improved after 100 thermal cycles, indicating that the modified thermochemical heat storage materials exhibit better cyclic performance.

[0089] As shown in FIG11 , an embodiment of the present invention further provides an industrial production method of a thermochemical heat storage module, comprising the following process:

[0090] Mn3O4 and Fe2O3 powders were mixed in a molar ratio of 8:3 in a first mixer 11. After uniform mixing, the mixture was passed into a first calcining furnace 12 for calcination at 1000°C. After cooling to room temperature through a first heat exchanger 13, the mixture was passed into a first grinder 14 and a first sieve 15 for grinding and screening to a particle size of no greater than 2 microns, thereby obtaining a manganese-iron composite metal oxide heat storage material.

[0091] Mn3O4 and SiO2 powders were mixed in a molar ratio of 1:3 in a second mixer 21. After uniform mixing, the mixture was passed into a second calcining furnace 22 for calcination at 1100°C. After cooling to room temperature through a second heat exchanger 23, the mixture was passed into a second grinder 24 and a second sieve 25 for grinding and sieving to a particle size of no greater than 2 microns, thereby obtaining a manganese silicate modifier.

[0092] The manganese-iron composite metal oxide heat storage material and the manganese silicate modifier are introduced into a third mixer 31 at a mass ratio of 99:1 and thoroughly mixed. After uniform mixing, the mixture is mixed with a binder and extruded into a thermochemical heat storage module using an extruder 32. The thermochemical heat storage module weighs no less than 100g. The temperature is then slowly raised to 800°C via a third heat exchanger 33 and passed into a third calcining furnace 34 for calcination. The thermochemical heat storage module has a compressive strength greater than 0.2 MPa. After calcination, the thermochemical heat storage module is placed in a storage tank 35 for storage and subsequent heat storage / release applications. It should be noted that during the preparation of the manganese-iron composite metal oxide heat storage material, the molar ratio of Mn3O4 to Fe2O3 powder ranges from 8:3 to 1:1, and the molar ratio of Mn3O4 to SiO2 powder ranges from 1:6 to 7:3. The dosage used in industrial production is in the ton range. Under these molar ratio parameters, the resulting thermochemical heat storage module exhibits excellent heat storage performance and good cycle performance.

[0093] Correspondingly, this embodiment provides a production system for a thermochemical heat storage module, comprising: a thermochemical heat storage material production device, a modifier production device, and a modified thermochemical heat storage material production device. The thermochemical heat storage material production device includes a first mixer 11, a first calcining furnace 12, a first heat exchanger 13, a first grinder 14, and a first filter 15, which are arranged in sequence;

[0094] The modifier production device includes a second mixer 21, a second calcining furnace 22, a second heat exchanger 23, a second grinder 24, and a second filter sieve 25, which are arranged in sequence;

[0095] A Mn3O4 supply pipeline 4 is connected between the first mixer and the second mixer, for supplying Mn3O4 to the first mixer 11 and the second mixer 21;

[0096] The modified thermochemical heat storage material production device includes a third mixer 31, an extruder 32, a third heat exchanger 33, a third calcining furnace 34, and a storage tank 35, which are arranged in sequence.

[0097] The outlets of the first filter screen 15 and the second filter screen 25 are connected to the third mixer 31, and the outlet of the third mixer 31 is connected to the extruder 32. The thermochemical heat storage module at the outlet of the extruder 32 exchanges heat with the third heat exchanger 33. The high-temperature heat source in the third heat exchanger 33 comes from the calcination waste heat at the outlets of the first heat exchanger 13 and the second heat exchanger 23. After heat exchange, the thermochemical heat storage module enters the third calcining furnace 34 for calcination. The calcined thermochemical heat storage module enters the storage tank 35 for storage for standby use.

[0098] It should be noted that the production system also includes a device for controlling Mn3O4, Fe2O3, SiO 2、The on-off valve 5 for the flow rate of the adhesive, etc., and the arrows in the flow chart indicate the steps of the production process.

[0099] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A thermochemical heat storage material modifier, characterized in that: The general formula of the thermochemical heat storage material modifier is M y SiO z ; Wherein, M = one or more of Co, Zn, Ni, Zr, Cu, Cr, Mg, and y and z are real numbers.

2. The thermochemical heat storage material modifier according to claim 1, characterized in that: The particle size of the thermochemical heat storage material modifier is no greater than 2 μm.

3. A method for preparing a thermochemical heat storage material modifier according to claim 1 or 2, characterized in that: The following steps are involved: Step S11: providing a metal oxide corresponding to M and SiO2, wherein M also includes Mn, and the metal oxide corresponding to Mn is manganese tetraoxide; Step S12: fully mixing the metal oxide corresponding to M with SiO2 in proportion to obtain a first precursor; Step S13: calcining the first precursor obtained in step S12, taking it out, grinding it into powder, and obtaining the thermochemical heat storage material modifier.

4. The method for preparing the thermochemical heat storage material modifier according to claim 3, characterized in that: The calcination temperature of the first precursor is 700-1100° C., and the calcination time is 0.5-8 hours.

5. A method for preparing a thermochemical heat storage material modifier as claimed in claim 1 or 2, characterized in that: The preparation method is a co-precipitation method, which comprises the following steps: Step S21: dispersing the silicon source in deionized water to form a uniform solution, and adding alkali to the uniform solution to adjust the pH value of the suspension to alkaline; Step S22: adding the metal salt corresponding to M to the uniform solution obtained in step S21 to obtain a precipitate and a supernatant; Step S23: filtering and separating the supernatant and the precipitate obtained in step S22 to obtain filter residues, washing the filtered filter residues with deionized water and ethanol, and drying the washed filter residues at room temperature to obtain a thermochemical heat storage material modifier.

6. A modified thermochemical heat storage material, characterized in that: include: The main heat storage material, the general formula of the main heat storage material is: (Mn 1-x Fe x )2O3; The thermochemical heat storage material modifier according to any one of claims 1 to 3; the general formula of the modified chemical heat storage material is (Mn 1-x Fe x )2O3·nM y SiO z , where 0.1 < x < 0.4, 0 < n < 0.4, and the thermochemical heat storage material modifier is attached to the surface of the main heat storage material.

7. The modified thermochemical heat storage material according to claim 6, characterized in that: The value range of n is 0.01-0.

05.

8. A method for preparing the modified thermochemical heat storage material according to claim 6 or 7, characterized in that: The following steps are involved: Step S31: providing a manganese-iron composite metal oxide heat storage material; Step S32: providing a thermochemical heat storage material modifier according to any one of claims 1 to 6; Step S33: The manganese-iron composite metal oxide heat storage material obtained in step S32 is mixed with the thermochemical heat storage material modifier in step S33 in a prescribed ratio to obtain a modified manganese-iron composite metal oxide heat storage material.

9. The method for preparing the modified thermochemical heat storage material according to claim 8, characterized in that: The preparation method of the manganese-iron composite metal oxide heat storage material comprises: S41: fully mixing manganese tetraoxide and ferric oxide to obtain a second precursor; S42: calcining the second precursor at high temperature, taking it out, grinding it into powder, and obtaining a manganese-iron composite metal oxide heat storage material.

10. A method for preparing a modified thermochemical heat storage module, characterized in that: The following steps are involved: Step S51: Mn3O4 and Fe2O3 powders are put into a mixer in a molar ratio of 8:3 to 1:1 and mixed evenly, and then the evenly mixed Mn3O4 and Fe2O3 powders are calcined to obtain a main heat storage material, and the calcined main heat storage material is cooled, ground, and screened to a desired particle size; Step S52: Mn3O4 and SiO2 powders are put into a mixer in a molar ratio of 1:6 to 7:3 and mixed evenly, and then the evenly mixed Mn3O4 and SiO2 powders are calcined to obtain a thermochemical heat storage material modifier, and the calcined thermochemical heat storage material modifier is cooled, ground, and screened to a desired particle size; Step S53: uniformly mixing the main heat storage material obtained in step S51 and the thermochemical heat storage material modifier obtained in step S52 in a prescribed ratio to obtain a modified thermochemical heat storage material; Step S54: providing an adhesive, and uniformly mixing the adhesive with the modified thermochemical heat storage material in step S53; Step S55: Extruding the modified thermochemical heat storage material and the binder uniformly mixed in step S52 into a thermochemical heat storage module; Step S56: exchanging heat between the surplus generated by the calcination in step S51 and step S52 and the heat exchanger, wherein the heat exchanger absorbs the heat generated by the calcination and transfers the heat to the thermochemical heat storage module in step S55, so that the thermochemical heat storage module is heated to a specified temperature; Step S57: calcining the thermochemical heat storage module obtained in step S56.

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