Modifiers, modified thermochemical thermal storage materials, modules and their preparation methods

Abstract

This invention provides a modifier, a modified thermochemical thermal storage material, a module, and a method for preparing the same. The general formula for the modifier of the thermochemical thermal storage material is M. y SiO z Where M = one or more of Co, Zn, Ni, Zr, Cu, Cr, and Mg, and y and z are real numbers. Adding this modifier to thermochemical thermal storage materials results in no byproducts being generated during the formation of the modified thermal storage material. This ensures the thermal storage performance of the thermochemical thermal storage material while inhibiting the growth of crystals on the surface of the material, thus improving its resistance to sintering and its stability under long-term high-temperature cycling.

Description

Technical Field

[0001] This invention relates to the field of energy storage, specifically to a modifier, a modified thermochemical thermal storage material, a module, and a method for preparing the same. Background Technology

[0002] Thermochemical thermal energy storage utilizes reversible thermochemical reactions to store and release thermal energy. The energy storage density of thermochemical thermal energy storage materials typically ranges from 0.5 to 3 GJ / m³. 3 It has a heat capacity of about 810 times that of sensible heat materials and more than twice that of latent heat materials. Moreover, it has low heat loss during long-term storage, and is therefore considered one of the most promising heat storage methods for the future.

[0003] High-temperature thermochemical energy storage technology based on metal oxides (such as cobalt, manganese, copper, and iron) achieves energy storage / release through reduction / oxidation reactions between metal oxides of different valence states. Storage temperatures can reach over 800℃, and energy storage densities can reach 300–1000 kJ / kg within a relatively small temperature variation range. However, it also suffers from performance instability and short cycle life during long-term reactions, severely restricting its development and application. Summary of the Invention

[0004] To address the above problems, this invention provides a modifier, a modified thermochemical thermal storage material, a module, and a method for preparing the same. By adding the modifier to the thermochemical thermal storage material, no byproducts are generated during the formation of the modified thermal storage material. This ensures the thermal storage performance of the thermochemical thermal storage material while inhibiting the growth of crystals on the surface of the material, thereby improving its resistance to sintering and its stability under long-term high-temperature cycling.

[0005] The first aspect of this invention provides a thermochemical thermal storage material modifier, wherein the general formula of the thermochemical thermal storage material modifier is M. y SiO z Where M = one or more of Co, Zn, Ni, Zr, Cu, Cr, and Mg, and y and z are real numbers.

[0006] According to this technical solution, the thermochemical thermal storage material modifier and the thermochemical thermal storage material generate new chemical bonds due to the interaction of charges. This allows the thermochemical thermal storage material modifier to stably adhere to the surface of the thermochemical thermal storage material through the pinning effect, inhibiting the growth of grains on the surface of the thermochemical thermal storage material. This prevents the thermochemical thermal storage material from undergoing large-area sintering due to excessive grain growth, thereby improving the anti-sintering ability and cycle stability of the thermochemical thermal storage material.

[0007] In the optional technical solutions of the present invention, the particle size of the thermochemical thermal storage material modifier is not greater than 2 μm.

[0008] According to this technical solution, compared with the particle size of thermochemical thermal storage materials, the particle size of the thermochemical thermal storage material modifier is no more than 2μm, which is relatively small; the larger specific surface area to volume ratio of the thermochemical thermal storage material modifier helps it to be adsorbed on the surface of the thermochemical thermal storage material.

[0009] The second aspect of the present invention provides a method for preparing a thermochemical thermal storage material modifier, comprising the following steps: Step S11: providing a metal oxide corresponding to M and SiO2, wherein M further includes Mn, and the metal oxide corresponding to Mn is manganese tetroxide; Step S12: thoroughly mixing the metal oxide corresponding to M and SiO2 in a certain 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 thermal storage material modifier.

[0010] According to this technical solution, the preparation of thermochemical thermal storage material modifiers by solid-phase synthesis has the advantages of low cost, large output, simple equipment and preparation process, and high production efficiency.

[0011] In an optional technical solution of the present invention, the calcination temperature of the first precursor is 700-1100℃ and the calcination time is 0.5-8h.

[0012] According to this technical solution, the metal oxide corresponding to M undergoes a chemical change with SiO2 during calcination. By controlling the calcination temperature and time, the rate of the chemical reaction can be increased, resulting in a single modifier silicate crystal. The modifier, combined with the thermochemical thermal storage material, can inhibit grain growth on the surface of the material at high temperatures, thereby improving its resistance to sintering.

[0013] A third aspect of this invention provides a method for preparing the above-mentioned thermochemical heat storage material modifier, wherein the preparation method is a co-precipitation method, and the co-precipitation method includes the following steps:

[0014] Step S21: Disperse the silicon source in deionized water to form a homogeneous solution, and add alkali to the homogeneous solution to adjust the pH of the suspension to alkaline.

[0015] Step S22: Add the metal salt corresponding to M to the homogeneous solution obtained in step S21 to obtain precipitate and supernatant;

[0016] Step S23: The supernatant obtained in step S22 is filtered and separated from the precipitate. The filter residue obtained by filtration is washed with deionized water and ethanol. The washed filter residue is dried at room temperature to obtain a thermochemical heat storage material modifier.

[0017] According to this technical solution, preparing the thermochemical energy storage material by the co-precipitation method can achieve high-purity separation of the modifier of the thermochemical energy storage material, with high selectivity and applicability. And 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.

[0018] In the fourth aspect of the present invention, a modified thermochemical energy storage material is provided, 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 adheres to the surface of the main energy storage material.

[0019] 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, using the silicate corresponding to the metal material M and controlling the value range of n can better inhibit the grain growth on the surface of the manganese-iron composite metal oxide energy storage material, ensuring that the modified thermochemical energy storage material has good energy storage performance, better anti-sintering ability and good cycle performance.

[0020] In an optional technical solution of the present invention, the value range of n is 0.01 - 0.05.

[0021] 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 adhesion 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 adhesion 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.

[0022] In the fifth aspect of the present invention, a preparation method of the above-mentioned modified thermochemical energy storage material is provided, 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.

[0023] According to this technical solution, the preparation of modified thermochemical thermal storage materials by solid-phase synthesis has the advantages of low cost, large output, simple equipment and preparation process, and high production efficiency.

[0024] In the optional technical solution of the present invention, the preparation method of manganese-iron composite metal oxide thermal storage material includes: S41: fully mixing manganese tetroxide and ferric oxide to obtain a second precursor; S42: taking out the second precursor after high-temperature calcination, grinding it into powder, and obtaining manganese-iron composite metal oxide thermal storage material.

[0025] According to this technical solution, manganese tetroxide and ferric oxide undergo contact, reaction, nucleation, and crystal growth reactions at their solid interfaces to ultimately obtain manganese-iron composite metal oxide thermal storage materials. This preparation method is low in cost, high in output, simple in equipment and preparation process, and has high production efficiency.

[0026] Using manganese tetroxide (MnO) as the manganese source, composite manganese-iron metal oxides were prepared via a high-temperature solid-state synthesis method. Under the same conditions, MnO showed better synthesis results compared to manganese trioxide (MnO). The principle of the high-temperature solid-state synthesis method is to place the mixed raw materials under high-temperature conditions (usually between 600℃ and 1000℃). At this temperature, the solid raw materials undergo a chemical reaction, and the metal ions in the raw materials begin to migrate and rearrange, forming a new crystal structure. MnO's crystal structure corresponds to an orthorhombic crystal system, and its lattice stability is high, making its lattice structure less prone to destruction. Therefore, its composite effect with ferric oxide (MnO) is poor during the synthesis stage, thus affecting subsequent redox reactions. In contrast, MnO, composed of MnO, exhibits better synthesis results. 2+ and Mn 3+ With its ionic composition and complex crystal structure, it is more prone to structural changes under certain conditions, and its chemical reaction with ferric oxide is also more complete, thus yielding a more ideal manganese-iron composite metal oxide thermal storage material.

[0027] This invention provides a method for preparing a modified thermochemical thermal storage module, comprising the following steps:

[0028] Step S51: Add Mn3O4 and Fe2O3 powders into a mixer at a molar ratio of 8:3 to 1:1 and mix them evenly. Then, calcine the evenly mixed Mn3O4 and Fe2O3 powders to obtain the main heat storage material. After cooling the calcined main heat storage material, grind it and screen it to the required particle size.

[0029] Step S52: Add Mn3O4 and SiO2 powders into a mixer at a molar ratio of 1:6 to 7:3 and mix them evenly. Then, calcine the evenly mixed Mn3O4 and SiO2 powders to obtain a thermochemical heat storage material modifier. After cooling the calcined thermochemical heat storage material modifier, grind it and screen it to the required particle size.

[0030] Step S53: Mix the main thermal storage material obtained in step S51 with the thermochemical thermal storage material modifier obtained in step S52 in a specified ratio to obtain the modified thermochemical thermal storage material.

[0031] Step S54: Provide an adhesive and mix the adhesive uniformly with the modified thermochemical heat storage material from step S53;

[0032] Step S55: The modified thermochemical thermal storage material and binder mixed evenly in step S52 are extruded and molded into a thermochemical thermal storage module.

[0033] Step S56: The residual heat generated by calcination in steps S51 and S52 is exchanged with the heat exchanger. The heat exchanger absorbs the heat generated by calcination and transfers it to the thermochemical heat storage module in step S55, so that the thermochemical heat storage module is heated to the specified temperature.

[0034] Step S57: Calcine the thermochemical thermal storage module obtained in step S56. Attached Figure Description

[0035] Figure 1 This is a SEM image of the modifier S1 in an embodiment of the present invention.

[0036] Figure 2 This is a SEM image of the modifier S2 in an embodiment of the present invention.

[0037] Figure 3 This is a SEM image of the modifier S3 in an embodiment of the present invention.

[0038] Figure 4 This is the X-ray diffraction pattern of the modifier S1 in the embodiments of the present invention.

[0039] Figure 5 This is the X-ray diffraction pattern of the modifier S2 in the embodiment of the present invention.

[0040] Figure 6 This is the X-ray diffraction pattern of the modifier S3 in the embodiments of the present invention.

[0041] Figure 7 This is a thermogravimetric analysis diagram of sample G1 after 100 cycles in an embodiment of the present invention.

[0042] Figure 8 This is a thermogravimetric analysis diagram of sample G2 after 100 cycles in an embodiment of the present invention.

[0043] Figure 9 This is a thermogravimetric analysis diagram of sample G3 after 100 cycles in an embodiment of the present invention.

[0044] Figure 10This is a thermogravimetric analysis diagram of sample G4 after 100 cycles in an embodiment of the present invention.

[0045] Figure 11 This is a schematic diagram of the preparation method of the modified thermochemical thermal storage module in the embodiments of the present invention.

[0046] Figure label:

[0047] First mixer 11; First calcining furnace 12; First heat exchanger 13; First grinder 14; First filter screen 15; Second mixer 21; Second calcining furnace 22; Second heat exchanger 23; Second grinder 24; Second filter screen 25; Third mixer 31; Extruder 32; Third heat exchanger 33; Third calcining furnace 34; Storage tank 35. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] 1. Material preparation

[0050] 1.1 Preparation of thermochemical heat storage material modifiers

[0051] 1.1.1 Solid-phase synthesis method

[0052] Step S11: Provide the 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 iron(III) oxide;

[0053] Step S12: Mix the metal oxide corresponding to M with SiO2 in a certain proportion to obtain the first precursor;

[0054] Step S13: The first precursor obtained in step S12 is calcined and then taken out and ground into powder to obtain a thermochemical heat storage material modifier.

[0055] Specifically, taking manganese silicate modifier as an example: 0.01 mol of manganese tetroxide and 0.03 mol of silicon dioxide are placed in a ball mill jar and mixed for 30 minutes to obtain the first precursor. The first precursor is then placed in a muffle furnace and calcined at 1100℃ for 4 hours. After cooling, it is ground and sieved to obtain powder with a particle size of less than 2 μm, thus obtaining manganese silicate modifier S3.

[0056] In a preferred embodiment of the present invention, the particle size of the thermochemical thermal storage material modifier is 10 nm-2 μm. More preferably, the particle size of the thermochemical thermal storage material modifier is 60-400 nm. In some embodiments, the particle size of the thermochemical thermal storage material modifier may also be 600-800 nm, 900 nm, 1500 nm, 1800 nm, etc.

[0057] It should be noted that technicians can adjust the calcination temperature to 700-1100℃ and the calcination time to 0.5-8h as needed, and are not limited to the examples given in this embodiment.

[0058] 1.1.2 Coprecipitation method

[0059] 0.05 mol Na₂SiO₃·9H₂O was dissolved in deionized water to obtain a homogeneous solution, and NaOH solid (or ammonia) was added to adjust the pH of the homogeneous solution to 8–10. 0.1 mol M(NO₃)m (M = one or more of Co, Zn, Ni, Zr, Cu, Cr, and Mg) was rapidly added to the homogeneous solution to form a precipitate, and stirring was continued for 2 hours (preferably at 25–40°C for 0.5–2 hours). The residue was filtered and washed repeatedly with deionized water and ethanol, and then dried at room temperature for 12 hours (drying time can be 6–24 hours, which can be adjusted by technicians according to actual conditions) to obtain silicate modified additive powder M. y SiO z .

[0060] Nitrate M(NO3) was selected. m As a source of metal cations, nitrate ions are more polar to water due to the differences in crystal structure and chemical bond properties between nitrates and chlorides, resulting in higher solubility of nitrates in water and facilitating a more complete reaction. Furthermore, chlorides are generally more toxic than nitrates, especially 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 serves two purposes: firstly, it avoids introducing new impurities, and secondly, it prevents the hydrolysis of sodium silicate.

[0061] The thermochemical thermal storage material prepared by the co-precipitation method uses an amorphous modifier. The amorphous modifier enhances the adsorption capacity with the surface of the host thermal storage material, while the disordered atomic arrangement of the amorphous material also provides greater compatibility for the electronic structure of the modified thermochemical thermal storage material.

[0062] 1.2 Preparation of Thermochemical Thermal Storage Materials

[0063] Weigh out 0.8 mol of reagent-grade Mn3O4 and 0.3 mol of reagent-grade Fe2O3, respectively, and place them in a ball mill. Mill for 30 minutes to ensure thorough mixing, with a preferred mixing time of 0.5-2 hours. Then, calcine the mixture in a muffle furnace at 1000℃ for 8 hours. After cooling, remove and grind the mixture. After sieving, obtain a black powdery main heat storage material: (Mn3O4 + Fe2O3)2O3 + Fe2O3. 0.8 Fe 0.2 )2O3.

[0064] 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 powder is composited 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.

[0065] Using Mn3O4 as the manganese source, composite manganese-iron metal oxides were prepared via a high-temperature solid-state synthesis method. Under the same conditions, Mn3O4 showed better synthesis results compared to Mn2O3. The principle of the high-temperature solid-state synthesis method is to place the mixed raw materials under high-temperature conditions (usually between 600℃ and 1000℃). 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, forming a new crystal structure. Manganese trioxide (Mn2O3) has an orthorhombic crystal system, with high lattice stability and a lattice structure that is not easily destroyed. Therefore, its composite effect with Fe2O3 in the synthesis stage is poor, thus affecting subsequent redox reactions. In contrast, Mn3O4, composed of Mn... 2+ and Mn 3+ With its ionic composition and complex crystal structure, it is more prone to structural changes under certain conditions, and its chemical reaction with Fe2O3 is more complete, thus yielding a high-performance manganese-iron composite metal oxide thermal storage material.

[0066] 1.3 Preparation of Modified Thermochemical Thermal Storage Materials

[0067] Take 4.95g of manganese-iron composite metal oxide and 0.05g of thermochemical heat storage material modifier and place them together in a ball mill jar. Mix them by ball milling for 30 minutes and then remove them to obtain the modified manganese-iron composite metal oxide heat storage material.

[0068] Depending on the type of thermochemical heat storage material modifier and the preparation method selected, the following specific examples can be obtained:

[0069] Amorphous cobalt silicate (CoSiO3) synthesized by co-precipitation was selected as the thermochemical heat storage material modifier S1, with a doping mass ratio of 0.01. The resulting modified manganese-iron composite metal oxide heat storage material G1 is (Mn0.8 Fe 0.2 )2O3·0.01CoSiO3.

[0070] Amorphous copper silicate CuSiO3 synthesized by co-precipitation was selected as the thermochemical heat storage material modifier S2, with a doping mass ratio of 0.01. The resulting modified manganese-iron composite metal oxide heat storage material G2 is (Mn 0.8 Fe 0.2 )2O3·0.01CuSiO3.

[0071] Manganese silicate MnSiO3 synthesized by solid-state synthesis was selected as the thermochemical heat storage material modifier S3, with a doping mass ratio of 0.01. The resulting modified manganese-iron composite metal oxide heat storage material G3 was (Mn 0.8 Fe 0.2 )2O3·0.01MnSiO3(sp).

[0072] A thermochemical thermal storage material G4:(Mn) was prepared by solid-state synthesis without the addition of thermochemical thermal storage material modifiers. 0.8 Fe 0.2 )2O3.

[0073] In this embodiment, during the synthesis of the uniformly mixed powdered thermal storage material and the amorphous silicate, the amorphous silicate additive can be uniformly and firmly adhered to the surface of the thermal storage material. Since the particle size of the amorphous silicate additive is no greater than 2 μm, it has a smaller particle size compared to the manganese-iron composite metal oxide thermal storage material prepared by solid-state synthesis (the ratio of the particle size of the amorphous silicate modifier to the particle size of the thermal storage material is 0.001 to 0.25, preferably 0.1 to 0.25). Simultaneously, the larger surface area to volume ratio facilitates its adsorption on the surface of the thermal storage material. This is because the high specific surface area of ​​the small particles makes the charge effect more significant, resulting in a stable interaction between the small particles and the thermal storage material. This prevents the agglomeration of large particles in the thermal storage material during the redox process, effectively improving the sintering phenomenon that occurs in the thermal storage material under high-temperature reaction conditions, thus obtaining a long-life / high-performance modified manganese-iron composite metal oxide thermal storage material.

[0074] 2. Material Characterization

[0075] The modified manganese-iron composite metal oxide thermal storage material prepared by the above method was characterized by the following experiments.

[0076] The equipment used for high-temperature calcination was a KSL-1200X box furnace from Hefei Kejing Company, 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 (Germany), X-ray diffraction (XRD) analysis was conducted using an Xpert Powder X-ray diffractometer from Panaco (Netherlands), and thermogravimetric analysis (TG) was performed using a TGA / DSC3+ simultaneous thermal analyzer from Mettler (Switzerland).

[0077] 2.1 Scanning Electron Microscope

[0078] Figure 1 , Figure 2 and Figure 3 These are SEM images of the modified additives S1-S3 in this embodiment. Figure 1 , Figure 2 As shown, amorphous silicate modifiers have small particle sizes and very loose particle structures. Therefore, compared to... Figure 3 The bulk structure of the mesocrystalline modifier allows the amorphous silicate additive to adhere well 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 particles, and improving the cyclic thermal storage performance of the modified manganese-iron composite metal oxide thermal storage material.

[0079] 2.2 X-ray diffraction

[0080] Figure 4 , Figure 5 The X-ray diffraction patterns correspond to modifiers S1-S2 in this embodiment. The horizontal axis represents twice the incident angle of the X-rays, and the vertical axis represents the intensity after diffraction. Figure 4 , Figure 5 As can be seen, modifiers S1 and S2 exhibit typical amorphous diffraction peaks, indicating that the sample is an amorphous substance. Simultaneously, characteristic peaks of the corresponding silicates are also present in the figure, indicating that the corresponding amorphous silicate modifiers were successfully prepared using the method described in the implementation embodiment. Figure 6 The manganese silicate additive S3 prepared by solid-state synthesis crystallizes well at high temperature, forming clear and strong silicate diffraction peaks, indicating that silicates were successfully synthesized at high temperature using the corresponding metal oxide and silicon oxide.

[0081] 2.3 Thermogravimetric Analysis

[0082] The thermal storage performance of the modified manganese-iron composite metal oxide thermal storage material was determined using the following experiments. The modified manganese-iron composite metal oxide thermal storage materials (samples G1-G3) and the control sample manganese-iron composite metal oxide thermal storage material G4 were placed on a thermochemical experimental platform for thermal cycling experiments.

[0083] The temperature control program was as follows: first, the temperature was raised from room temperature to 700℃, then raised from 700℃ to 1000℃ and held for 30 minutes, then lowered from 1000℃ to 700℃ and held for 30 minutes; the heating and cooling rates were both 10℃ / min, and the air flow rate was 1L / min (pO2 = 0.21). The process of heating to 1000℃ and then cooling back to 700℃ was considered one cycle. After 100 cycles, heating was stopped, and 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℃ / min, the cooling rate was 10℃ / min, and the air flow rate was 50 ml / min (pO2 = 0.21).

[0084] The temperature control procedure for thermogravimetric analysis of samples G1, G2, G3, and G4 was as follows: first, the temperature was increased from 50℃ to 1000℃ and held for 10 minutes; then, the temperature was decreased from 1000℃ to 700℃.

[0085] The experimental results are shown in Table 1 and Figure 7-10 As shown in Table 1, the thermogravimetric analysis results of samples G1-G4 after thermal cycling experiments are presented. Figure 7-10 The thermogravimetric analysis curves of samples G1-G4 after cycling are shown below.

[0086] Table 1

[0087]

[0088]

[0089] After repeated cycles, thermal storage materials are prone to crystal growth, leading to coarsening and densification of the microstructure. Furthermore, sintering causes microparticle agglomeration, reducing the material's specific surface area, hindering oxygen mass transfer, and severely deteriorating reaction characteristics. This is a significant factor contributing to the decreased cycle stability of thermochemical thermal storage materials. Thermogravimetric analysis results show that, compared to unmodified thermochemical thermal storage materials (re-oxidation rate below 40%) and reduction rate (90.13%), modified thermochemical thermal storage materials (both crystalline and amorphous) exhibit significantly improved re-oxidation and re-reduction rates after 100 thermal cycles, indicating that the modified thermochemical thermal storage materials demonstrate superior cycle performance.

[0090] like Figure 11 As shown, an embodiment of the present invention also provides an industrial production method for a thermochemical thermal storage module, comprising the following steps:

[0091] Mn3O4 and Fe2O3 powders were mixed in a molar ratio of 8:3 in the first mixer 11. After uniform mixing, the mixture was fed into the first calcining furnace 12 and calcined at 1000℃. After being cooled to room temperature by heat exchange in the first heat exchanger 13, the mixture was then fed into the first grinding mill 14 and the first filter sieve 15 for grinding and sieving until the particle size was no larger than 2 micrometers, thus obtaining the manganese-iron composite metal oxide thermal storage material.

[0092] Mn3O4 and SiO2 powders are added to the second mixer 21 at a molar ratio of 1:3 for mixing. After uniform mixing, the mixture is fed into the second calcining furnace 22 for high-temperature calcination at 1100℃. After being cooled to room temperature by heat exchanger 23, the mixture is fed into the second grinder 24 and the second filter sieve 25 for grinding and sieving until the particle size is no greater than 2 micrometers, thus obtaining the manganese silicate modifier.

[0093] The aforementioned manganese-iron composite metal oxide thermal storage material and manganese silicate modifier were thoroughly mixed in a third mixer 31 at a mass ratio of 99:1. After uniform mixing, the mixture was combined with a binder and extruded using an extruder 32 to form a thermochemical thermal storage module. The mass of each thermochemical thermal storage module was not less than 100g. The module was then slowly heated to 800℃ through a third heat exchanger 33 and calcined in a third calcining furnace 34. The compressive strength of the thermochemical thermal storage module was greater than 0.2MPa. After calcination, the module was 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 thermal storage material, the molar ratio of Mn3O4 to Fe2O3 powder ranged from 8:3 to 1:1, and the molar ratio of Mn3O4 to SiO2 powder ranged from 1:6 to 7:3. The dosage used in industrial production was in the ton range. Under these molar ratio parameters, the obtained thermochemical thermal storage module exhibited excellent thermal storage performance and good cycle performance.

[0094] Correspondingly, this embodiment provides a production system for a thermochemical thermal storage module, including: a thermochemical thermal storage material production device, a modifier production device, and a modified thermochemical thermal storage material production device. The thermochemical thermal storage material production device includes a first mixer 11, a first calcining furnace 12, a first heat exchanger 13, a first grinding mill 14, and a first filter screen 15 arranged sequentially.

[0095] The modifier production device includes a second mixer 21, a second calcining furnace 22, a second heat exchanger 23, a second grinding mill 24, and a second filter screen 25 arranged in sequence.

[0096] A Mn3O4 supply pipeline 4 is connected between the first mixer and the second mixer, which is used to supply Mn3O4 to the first mixer 11 and the second mixer 21.

[0097] 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 arranged sequentially. Among them,

[0098] 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. The thermochemical heat storage module after heat exchange enters the third calcining furnace 34 for calcination. The thermochemical heat storage module after calcination enters the storage tank 35 for storage and standby.

[0099] It should be noted that the production system also includes switching valves 5 for controlling the flow rates of Mn3O4, Fe2O3, SiO2, adhesives, etc. The arrows in the flow chart indicate the steps of the production process.

[0100] The above are merely 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 within the protection scope of the present invention.

Claims

1. A modified thermochemical heat storage material, characterized in that, include: The main thermal storage material is a metal oxide. A thermochemical thermal storage material modifier, wherein the thermochemical thermal storage material modifier is an amorphous silicate, and the general formula of the thermochemical thermal storage material modifier is M. y SiO z Where M = one or more of Co, Zn, Ni, Zr, Cu, Cr, and Mg, and y and z are real numbers; The main heat storage material is manganese-iron composite metal oxide, and its general formula is: (Mn 1-x Fe x )2O3, where 0.1 < x < 0.4; the general formula of the modified chemical heat storage material is (Mn 1-x Fe x )2O3·nM y SiO z , where 0 < n < 0.4, and the modifier of the thermochemical heat storage material is attached to the surface of the main heat storage material.

2. The modified thermochemical thermal storage material according to claim 1, characterized in that, The value of n ranges from 0.01 to 0.

05.

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

4. A preparation method for preparing a thermochemical heat storage material modifier as described in any one of claims 1-3, characterized in that, The preparation method is a coprecipitation method, which includes the following steps: Step S21: Disperse the silicon source in deionized water to form a homogeneous solution, and add alkali to the homogeneous solution to adjust the pH of the suspension to alkaline. Step S22: Add the metal salt corresponding to M to the homogeneous solution obtained in step S21 to obtain precipitate and supernatant; Step S23: The supernatant and precipitate obtained in step S22 are filtered to separate the filter residue. The filter residue is washed with deionized water and ethanol. The washed filter residue is dried at room temperature to obtain a thermochemical heat storage material modifier.

5. A preparation method for preparing the modified thermochemical thermal storage material as described in claim 1 or 2, characterized in that, Includes the following steps: Step S31: Provide manganese-iron composite metal oxide thermal storage material; Step S32: Provide a thermochemical heat storage material modifier as described in any one of claims 1-4; Step S33: Mix the manganese-iron composite metal oxide thermal storage material obtained in step S31 with the thermochemical thermal storage material modifier in step S32 in a specified ratio to obtain the modified manganese-iron composite metal oxide thermal storage material.

6. The preparation method according to claim 5, characterized in that, The preparation method of the manganese-iron composite metal oxide thermal storage material includes: S41: Manganese tetroxide and ferric oxide are thoroughly mixed to obtain the second precursor; S42: The second precursor is calcined at high temperature and then taken out and ground into powder to obtain manganese-iron composite metal oxide thermal storage material.

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