High performance composite calcium-based thermochemical energy storage particles, methods of making and using the same

Abstract

The application discloses a kind of high-performance composite calcium-based thermochemical energy storage particles and preparation method and application thereof, comprising: 1) calcium source, heat-conducting reinforcing phase, structural reinforcing phase, pore-forming agent and binder are mixed to obtain forming mixture;2) the forming mixture is formed to obtain green body particles;3) the green body particles are dried and calcined to remove pore-forming agent, form calcium-containing reactive matrix with connected channels, to obtain calcined particles;4) form anti-agglomeration wear-resistant surface layer on the surface of calcined particles to obtain coated particles;5) the coated particles are activated to obtain high-performance composite calcium-based thermochemical energy storage particles, which have excellent characteristics of reactivity, heat transfer performance, mechanical strength, anti-agglomeration and anti-crushing performance.

Description

Technical Field

[0001] This invention belongs to the field of high-temperature thermochemical energy storage materials technology, and relates to a high-performance composite calcium-based thermochemical energy storage particle, its preparation method and application. Background Technology

[0002] The CaCO3 / CaO system has advantages such as abundant raw material reserves, low price, high theoretical heat storage density, and reaction temperature suitable for industrial waste heat and solar thermal utilization. This system can be achieved through the formula CaCO3... The reversible reaction of CaO + CO2 enables energy storage and release: in the heat storage stage, CaCO3 decomposes endothermally to form CaO and CO2, storing heat; in the exothermic stage, CaO reacts with CO2 to generate CaCO3 and release heat. However, natural limestone or ordinary calcium-based particles generally suffer from the following problems during repeated calcination / carbonation cycles: high-temperature calcination and cyclic reactions lead to pore structure collapse, grain sintering, and activity decay; the intrinsic thermal conductivity of CaCO3 / CaO is low, resulting in a large internal temperature gradient within the particles, limiting the reaction rate and bed heat transfer capacity; direct contact between particles at high temperatures easily leads to sintering necks, causing agglomeration, adhesion, and fluidization deterioration; while traditional dense surface coating can alleviate agglomeration to some extent, it easily hinders CO2 mass transfer, causing a decrease in reactivity; particles are prone to wear and breakage during transport, thermal cycling, and phase change volume changes, producing fine powder and further deteriorating heat transfer performance. Therefore, it is necessary to provide a high-performance composite calcium-based thermochemical energy storage particle that simultaneously considers reactivity, heat transfer performance, mechanical strength, anti-agglomeration, and anti-breakage properties. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-performance composite calcium-based thermochemical energy storage particle, its preparation method and application. The high-performance composite calcium-based thermochemical energy storage particle has excellent reactivity, heat transfer performance, mechanical strength, anti-agglomeration and anti-breakage properties.

[0004] To achieve the above objectives, this invention discloses a method for preparing high-performance composite calcium-based thermochemical energy storage particles, comprising: 1) Mix the calcium source, thermally conductive reinforcing phase, structural reinforcing phase, pore-forming agent and binder to obtain a molding mixture; 2) The molding mixture is molded to obtain green pellets; 3) The green particles are dried and calcined to remove the pore-forming agent and form a calcium-containing reactive matrix with interconnected pores to obtain calcined particles. 4) An anti-agglomeration and wear-resistant surface layer is formed on the surface of the calcined particles to obtain coated particles; 5) The coated particles are activated to obtain high-performance composite calcium-based thermochemical energy storage particles.

[0005] Furthermore, the calcium source is one or a combination of limestone, dolomite, calcium carbonate, calcium hydroxide, and calcium oxide.

[0006] Furthermore, the pore-forming agent is selected from one or more of starch, cellulose, polyvinyl alcohol, polymethyl methacrylate, toner, and graphite powder.

[0007] Furthermore, the calcination includes a first stage of removing organic components and a second stage of calcination activation; the second stage calcination temperature is 700℃-1050℃, and the holding time is 0.5h-10h.

[0008] Furthermore, the activation treatment includes at least one carbonation-calcination cycle.

[0009] Furthermore, the anti-agglomeration wear-resistant surface layer is made of composite inorganic particles of alumina and silica, or composite inorganic particles of alumina, silica and spinel; the anti-agglomeration wear-resistant surface layer is bonded to the particle surface by at least one of the following methods: electrostatic adsorption, inorganic binder bonding, sol-gel curing or sintering neck connection.

[0010] Furthermore, the content of calcium-containing reactive matrix in the high-performance composite calcium-based thermochemical energy storage particles is 80wt% to 90wt%, the content of thermally conductive reinforcing phase in the high-performance composite calcium-based thermochemical energy storage particles is 3wt% to 10wt%, and the content of anti-agglomeration and wear-resistant surface layer in the high-performance composite calcium-based thermochemical energy storage particles is 3wt% to 10wt%. The calcium-containing reactive matrix includes a structural reinforcing phase, which is one or more of calcium aluminate, magnesium aluminum spinel, calcium silicate, zirconium oxide, magnesium oxide and aluminum oxide, and the content of the structural reinforcing phase is 3 wt% to 10 wt% of the total mass of the high-performance composite calcium-based thermochemical energy storage particles.

[0011] Furthermore, the coverage of the anti-agglomeration wear-resistant surface layer is 50% to 80% of the outer surface area of ​​the calcined particles, and the average thickness of the anti-agglomeration wear-resistant surface layer is 50nm-30μm.

[0012] This invention discloses a high-performance composite calcium-based thermochemical energy storage particle, which is prepared based on the preparation method of the high-performance composite calcium-based thermochemical energy storage particle.

[0013] This invention discloses the application of high-performance composite calcium-based thermochemical energy storage particles in thermochemical energy storage systems.

[0014] The present invention has the following beneficial effects: The high-performance composite calcium-based thermochemical energy storage particles, their preparation method, and applications described in this invention utilize a CaCO3 / CaO active matrix with interconnected pores as the reaction host. A highly thermally conductive reinforcing phase is introduced inside the particles to construct a rapid heat transfer path, and a discontinuous anti-agglomeration and wear-resistant surface layer is constructed on the outer surface of the particles. This "discontinuous" anti-agglomeration and wear-resistant surface layer means that the surface layer does not completely seal the particle surface, retaining mass transfer windows that allow CO2 to enter and escape. Therefore, while isolating direct contact between particles and inhibiting the formation of sintering necks, the surface layer does not significantly hinder the gas diffusion required for the CaCO3 / CaO reaction. Furthermore, the particles possess a hierarchical pore structure composed of macropores, mesopores, and micropores. Macropores and mesopores facilitate rapid CO2 diffusion, while micropores provide the reaction interface. The thermally conductive reinforcing phase forms a continuous thermally conductive network within the matrix to reduce the internal heat transfer resistance of the particles. The structurally reinforcing phase, by forming a high-temperature resistant skeleton and point-like support structure, resists cracking and breakage caused by cyclic phase transformation, improving the compressive strength and thermal shock resistance of the particles. The internal interconnected channels, thermally conductive network, and surface discontinuities of the particles work together to balance heat transfer, mass transfer, anti-agglomeration, and strength. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0017] 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, not all, of the embodiments of the present invention. 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.

[0018] In the description of this invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0019] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0020] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this invention generally indicates that the preceding and following objects have an "or" relationship.

[0021] It should be understood that although terms such as first, second, third, etc., may be used in the embodiments of the present invention to describe the preset range, these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from one another. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0022] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0024] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0025] refer to Figure 1 The preparation method of the high-performance composite calcium-based thermochemical energy storage particles of the present invention includes the following steps: 1) Mix the calcium source, thermally conductive reinforcing phase, structural reinforcing phase, pore-forming agent and binder to obtain a molding mixture; 2) The molding mixture is granulated by extrusion granulation, spray granulation or spheroidization to obtain green pellets; 3) The green particles are dried and calcined to remove the pore-forming agent and form a calcium-containing reactive matrix with interconnected pores to obtain calcined particles. 4) Dry mechanical coating, fluidized bed coating or spray coating are used to form an anti-agglomeration and wear-resistant surface layer on the surface of the calcined particles to obtain coated particles; 5) The coated particles are activated to obtain high-performance composite calcium-based thermochemical energy storage particles.

[0026] In this embodiment, the calcium source is one or a combination of limestone, dolomite, calcium carbonate, calcium hydroxide, and calcium oxide.

[0027] In this embodiment, the pore-forming agent is selected from one or more of starch, cellulose, polyvinyl alcohol, polymethyl methacrylate, toner, and graphite powder.

[0028] In this embodiment, the calcination includes a first stage of removing organic components and a second stage of calcination activation; the second stage calcination temperature is 700℃-1050℃, and the holding time is 0.5h-10h.

[0029] In this embodiment, the activation treatment includes at least one carbonation-calcination cycle.

[0030] In this embodiment, the material of the anti-agglomeration wear-resistant surface layer is a composite inorganic particle of alumina and silicon oxide, or a composite inorganic particle of alumina, silicon oxide and spinel; the anti-agglomeration wear-resistant surface layer is bonded to the particle surface by at least one of the following methods: electrostatic adsorption, inorganic binder bonding, sol-gel curing or sintering neck connection.

[0031] The application of the high-performance composite calcium-based thermochemical energy storage particles in a thermochemical energy storage system, wherein the thermochemical energy storage system utilizes CaCO3 The reversible reaction of CaO+CO2 allows for heat storage and release, and the high-performance composite calcium-based thermochemical energy storage particles are applied to fixed-bed reactors, moving-bed reactors, fluidized-bed reactors, or gas-solid circulation reactors.

[0032] The high-performance composite calcium-based thermochemical energy storage particles contain 80 wt% to 90 wt% of calcium reactive matrix, 3 wt% to 10 wt% of thermally conductive reinforcing phase, and 3 wt% to 10 wt% of anti-agglomeration and wear-resistant surface layer.

[0033] In this embodiment, the anti-agglomeration wear-resistant surface layer is composed of inorganic particles with a particle size of 10nm to 5μm, wherein the inorganic particles are selected from one or more of Al2O3, SiO2, ZrO2, MgAl2O4, CaAl2O4 and mullite.

[0034] In this embodiment, the coverage of the anti-agglomeration wear-resistant surface layer is 50% to 80% of the outer surface area of ​​the calcined particles, and the average thickness of the anti-agglomeration wear-resistant surface layer is 50nm-30μm.

[0035] In this embodiment, the calcium-containing reactive matrix includes a structural reinforcement phase, which is one or a combination of calcium aluminate, magnesium aluminum spinel, calcium silicate, zirconium oxide, magnesium oxide and aluminum oxide. The content of the structural reinforcement phase is 3 wt% to 10 wt% of the total mass of the high-performance composite calcium-based thermochemical energy storage particles.

[0036] In this embodiment, the high-performance composite calcium-based thermochemical energy storage particles have a D50 particle size of 50 μm to 10 mm, a porosity of 10% to 50%, and at least some of the pores have a pore size of 0.05 μm to 50 μm.

[0037] In this embodiment, the thermally enhanced phase forms a three-dimensional thermally conductive network and at least a portion of it is exposed on the pore walls of the connecting channels to improve the heat transfer rate inside the particles.

[0038] It should be noted that the present invention uses a calcium-containing reactive matrix as CaCO3 / CaO with interconnected channels to allow gas to enter or escape from the interior of the particles; the thermally conductive reinforcing phase is selected from one or more of silicon carbide, aluminum nitride, boron nitride, graphite, graphene, and expanded graphite, and is dispersed inside the calcium-containing reactive matrix to form a thermally conductive pathway that penetrates the calcium-containing reactive matrix; the anti-agglomeration and wear-resistant surface layer covers the outer surface of the calcium-containing reactive matrix and is a discontinuous layer with discontinuous regions.

[0039] Example 1 This embodiment is used to prepare SiC thermally enhanced-Al2O3 / SiO2 composite surface calcium-based energy storage particles.

[0040] By weight, 80 wt% CaCO3 powder, 8 wt% SiC powder, 4 wt% calcium aluminate powder, 4 wt% starch pore-forming agent, 2 wt% polyvinyl alcohol binder and 2 wt% deionized water are mixed evenly; wherein, the D50 of CaCO3 powder is 5 μm to 30 μm and the D50 of SiC powder is 0.5 μm to 10 μm.

[0041] The mixture is extruded and spherical green pellets with a D50 of 0.5 mm to 2 mm by extrusion and sphericalization, and then dried at 80°C to 120°C for 4 to 12 hours.

[0042] The dried green particles are heated to 350°C to 550°C in air and held for 1 to 4 hours to remove organic components; then heated to 800°C to 950°C and held for 1 to 5 hours to obtain porous calcium-based matrix particles.

[0043] The matrix particles are mixed with nano-Al2O3, nano-SiO2 and inorganic silica sol to form a discontinuous composite surface layer of Al2O3 and SiO2 on the particle surface; wherein the mass ratio of Al2O3 to SiO2 is 1:(0.2~2) and the total amount of composite surface layer added is 3wt% to 10wt% of the total mass of the energy storage particles.

[0044] The coated particles were cured at 550°C to 800°C for 0.5 to 3 hours, followed by at least 3 calcination / carbonation activation cycles to obtain calcium-based thermochemical energy storage particles.

[0045] In this embodiment, the resulting particles have an active CaO phase, a SiC thermally conductive pathway, and a calcium aluminate-reinforced structure inside, and an Al2O3 / SiO2 composite discontinuous surface layer on the surface. The particle surface layer can reduce direct contact with high temperatures, while the internal channels and the discontinuous regions on the surface can ensure CO2 mass transfer.

[0046] Example 2 This embodiment is used to prepare expanded graphite thermally enhanced spinel surface calcium-based energy storage particles.

[0047] The following components are mixed according to their mass percentages: 84wt% CaCO3, 5wt% expanded graphite, 3wt% MgO, 3wt% Al2O3, 3wt% cellulose pore-forming agent, and 2wt% binder to obtain the molding mixture.

[0048] The mixture is spray-granulated to obtain green particles with a particle size of 100μm to 800μm.

[0049] The green pellets are subjected to segmented heat treatment in an inert or low-oxygen atmosphere, with a maximum heat treatment temperature of 750℃ to 950℃, to obtain calcium-based matrix particles with a hierarchical porous structure; MgO and Al2O3 form spinel or magnesium-aluminum composite reinforcement structures in subsequent heat treatment.

[0050] A fluidized bed coating method is used to introduce MgAl2O4 particles with a diameter of 50nm to 2μm and a small amount of Al2O3 particles onto the surface of the matrix particles, forming an intermittent wear-resistant surface layer with a coverage of 50% to 80%.

[0051] Calcium-based thermochemical energy storage particles were obtained by performing at least three calcination / carbonation activation cycles.

[0052] In this embodiment, expanded graphite provides a high thermal conductivity pathway, while the spinel surface layer and reinforcing structure improve the particle's wear resistance, thermal shock resistance, and anti-agglomeration ability. For particles containing carbon-containing thermally conductive reinforcing phases, it is preferable to perform high-temperature treatment and application in a low-oxygen or inert environment, or to reduce their oxidation risk through an outer inorganic shielding layer.

[0053] Example 3 The preparation method of the high-performance composite calcium-based thermochemical energy storage particles of the present invention includes the following steps: 1) Mix the calcium source, thermally conductive reinforcing phase, structural reinforcing phase, pore-forming agent and binder to obtain a molding mixture; 2) The molding mixture is extruded and granulated to obtain green pellets; 3) The green particles are dried and calcined to remove the pore-forming agent and form a calcium-containing reactive matrix with interconnected pores to obtain calcined particles. 4) A dry mechanical coating method is used to form an anti-agglomeration and wear-resistant surface layer on the surface of the calcined particles, resulting in coated particles; 5) The coated particles are activated to obtain high-performance composite calcium-based thermochemical energy storage particles.

[0054] In this embodiment, the calcium source is dolomite.

[0055] In this embodiment, the pore-forming agent is selected from cellulose.

[0056] In this embodiment, the calcination includes a first stage of removing organic components and a second stage of calcination activation; the second stage calcination temperature is 700℃ and the holding time is 10h.

[0057] In this embodiment, the activation treatment includes at least one carbonation-calcination cycle.

[0058] In this embodiment, the anti-agglomeration wear-resistant surface layer is made of composite inorganic particles of alumina and silicon oxide; the anti-agglomeration wear-resistant surface layer is bonded to the particle surface by an inorganic binder.

[0059] The application of the high-performance composite calcium-based thermochemical energy storage particles in a thermochemical energy storage system, wherein the thermochemical energy storage system utilizes CaCO3 The reversible reaction of CaO+CO2 enables heat storage and release, and the high-performance composite calcium-based thermochemical energy storage particles are applied to a moving bed reactor.

[0060] The high-performance composite calcium-based thermochemical energy storage particles contain 80 wt% calcium reactive matrix, 10 wt% thermally conductive reinforcing phase, and 10 wt% anti-agglomeration and wear-resistant surface layer.

[0061] In this embodiment, the anti-agglomeration and wear-resistant surface layer is composed of inorganic particles with a particle size of 5 μm, and the inorganic particles are selected from Al2O3.

[0062] In this embodiment, the coverage of the anti-agglomeration wear-resistant surface layer is 50% to 80% of the outer surface area of ​​the calcined particles, and the average thickness of the anti-agglomeration wear-resistant surface layer is 50 nm.

[0063] In this embodiment, the calcium-containing reactive matrix includes a structurally reinforcing phase, which is calcium aluminate, and the content of the structurally reinforcing phase is 3 wt% of the total mass of the high-performance composite calcium-based thermochemical energy storage particles.

[0064] In this embodiment, the high-performance composite calcium-based thermochemical energy storage particles have a D50 particle size of 50 μm, a porosity of 50%, and at least some of the pores have a pore size of 50 μm.

[0065] Example 4 The preparation method of the high-performance composite calcium-based thermochemical energy storage particles of the present invention includes the following steps: 1) Mix the calcium source, thermally conductive reinforcing phase, structural reinforcing phase, pore-forming agent and binder to obtain a molding mixture; 2) The molding mixture is extruded and granulated to obtain green pellets; 3) The green particles are dried and calcined to remove the pore-forming agent and form a calcium-containing reactive matrix with interconnected pores to obtain calcined particles. 4) Spray coating is used to form an anti-agglomeration and wear-resistant surface layer on the surface of the calcined particles, resulting in coated particles; 5) The coated particles are activated to obtain high-performance composite calcium-based thermochemical energy storage particles.

[0066] In this embodiment, the calcium source is limestone.

[0067] In this embodiment, the pore-forming agent is selected from starch.

[0068] In this embodiment, the calcination includes a first stage of removing organic components and a second stage of calcination activation; the second stage calcination temperature is 800℃ and the holding time is 2h.

[0069] In this embodiment, the activation treatment includes at least one carbonation-calcination cycle.

[0070] In this embodiment, the anti-agglomeration wear-resistant surface layer is made of composite inorganic particles of alumina, silicon oxide and spinel; the anti-agglomeration wear-resistant surface layer is bonded to the particle surface by electrostatic adsorption.

[0071] The application of the high-performance composite calcium-based thermochemical energy storage particles in a thermochemical energy storage system, wherein the thermochemical energy storage system utilizes CaCO3 The reversible reaction of CaO+CO2 enables heat storage and release, and the high-performance composite calcium-based thermochemical energy storage particles are applied to a fixed-bed reactor.

[0072] The high-performance composite calcium-based thermochemical energy storage particles contain 85 wt% calcium reactive matrix, 7 wt% thermally conductive reinforcing phase, and 8 wt% anti-agglomeration and wear-resistant surface layer.

[0073] In this embodiment, the anti-agglomeration and wear-resistant surface layer is composed of inorganic particles with a particle size of 1 μm, and the inorganic particles are selected from Al2O3.

[0074] In this embodiment, the coverage of the anti-agglomeration wear-resistant surface layer is 70% of the outer surface area of ​​the calcined particles, and the average thickness of the anti-agglomeration wear-resistant surface layer is 25 μm.

[0075] In this embodiment, the calcium-containing reactive matrix includes a structurally reinforcing phase, which is calcium aluminate, and the content of the structurally reinforcing phase is 6 wt% of the total mass of the high-performance composite calcium-based thermochemical energy storage particles.

[0076] In this embodiment, the high-performance composite calcium-based thermochemical energy storage particles have a D50 particle size of 9 mm, a porosity of 10% to 50%, and at least some of the pores have a pore size of 40 μm.

[0077] Example 5 The preparation method of the high-performance composite calcium-based thermochemical energy storage particles of the present invention includes the following steps: 1) Mix the calcium source, thermally conductive reinforcing phase, structural reinforcing phase, pore-forming agent and binder to obtain a molding mixture; 2) The molding mixture is granulated by rounding to obtain green pellets; 3) The green particles are dried and calcined to remove the pore-forming agent and form a calcium-containing reactive matrix with interconnected pores to obtain calcined particles. 4) Spray coating is used to form an anti-agglomeration and wear-resistant surface layer on the surface of the calcined particles, resulting in coated particles; 5) The coated particles are activated to obtain high-performance composite calcium-based thermochemical energy storage particles.

[0078] In this embodiment, the calcium source is a combination of limestone, dolomite, calcium carbonate, calcium hydroxide, and calcium oxide.

[0079] In this embodiment, the pore-forming agent is selected from a combination of starch, cellulose, polyvinyl alcohol, polymethyl methacrylate, toner, and graphite powder.

[0080] In this embodiment, the calcination includes a first stage of removing organic components and a second stage of calcination activation; the second stage calcination temperature is 1000℃ and the holding time is 9h.

[0081] In this embodiment, the activation treatment includes at least one carbonation-calcination cycle.

[0082] In this embodiment, the anti-agglomeration wear-resistant surface layer is made of composite inorganic particles of alumina, silicon dioxide and spinel; the anti-agglomeration wear-resistant surface layer is bonded to the particle surface through electrostatic adsorption, inorganic binder bonding, sol-gel curing and sintering neck connection.

[0083] The application of the high-performance composite calcium-based thermochemical energy storage particles in a thermochemical energy storage system, wherein the thermochemical energy storage system utilizes CaCO3 The reversible reaction of CaO+CO2 enables heat storage and release, and the high-performance composite calcium-based thermochemical energy storage particles are applied to a fixed-bed reactor.

[0084] The high-performance composite calcium-based thermochemical energy storage particles contain 90 wt% calcium reactive matrix, 3 wt% thermally conductive reinforcing phase, and 7 wt% anti-agglomeration and wear-resistant surface layer.

[0085] In this embodiment, the anti-agglomeration and wear-resistant surface layer is composed of inorganic particles with a particle size of 5 μm, and the inorganic particles are selected from mullite.

[0086] In this embodiment, the coverage of the anti-agglomeration wear-resistant surface layer is 70% of the outer surface area of ​​the calcined particles, and the average thickness of the anti-agglomeration wear-resistant surface layer is 20 μm.

[0087] In this embodiment, the calcium-containing reactive matrix includes a structurally reinforcing phase, which is alumina, and the content of the structurally reinforcing phase is 8 wt% of the total mass of the high-performance composite calcium-based thermochemical energy storage particles.

[0088] In this embodiment, the high-performance composite calcium-based thermochemical energy storage particles have a D50 particle size of 8 mm, a porosity of 10% to 50%, and at least some of the pores have a pore size of 40 μm.

[0089] Example 6 The preparation method of the high-performance composite calcium-based thermochemical energy storage particles of the present invention includes the following steps: 1) Mix the calcium source, thermally conductive reinforcing phase, structural reinforcing phase, pore-forming agent and binder to obtain a molding mixture; 2) The molding mixture is granulated by rounding to obtain green pellets; 3) The green particles are dried and calcined to remove the pore-forming agent and form a calcium-containing reactive matrix with interconnected pores to obtain calcined particles. 4) Spray coating is used to form an anti-agglomeration and wear-resistant surface layer on the surface of the calcined particles, resulting in coated particles; 5) The coated particles are activated to obtain high-performance composite calcium-based thermochemical energy storage particles.

[0090] In this embodiment, the calcium source is calcium oxide.

[0091] In this embodiment, the pore-forming agent is selected from carbon powder.

[0092] In this embodiment, the calcination includes a first stage of removing organic components and a second stage of calcination activation; the second stage calcination temperature is 900℃ and the holding time is 8h.

[0093] In this embodiment, the activation treatment includes at least one carbonation-calcination cycle.

[0094] In this embodiment, the anti-agglomeration wear-resistant surface layer is made of composite inorganic particles of alumina, silicon dioxide and spinel; the anti-agglomeration wear-resistant surface layer is bonded to the particle surface by a sintering neck connection.

[0095] The application of the high-performance composite calcium-based thermochemical energy storage particles in a thermochemical energy storage system, wherein the thermochemical energy storage system utilizes CaCO3 The reversible reaction of CaO+CO2 enables heat storage and release, and the high-performance composite calcium-based thermochemical energy storage particles are applied to a gas-solid circulation reactor.

[0096] The high-performance composite calcium-based thermochemical energy storage particles contain 90 wt% calcium reactive matrix, 7 wt% thermally conductive reinforcing phase, and 3 wt% anti-agglomeration and wear-resistant surface layer.

[0097] In this embodiment, the anti-agglomeration wear-resistant surface layer is composed of inorganic particles with a particle size of 3μm, and the inorganic particles are selected from MgAl2O4.

[0098] In this embodiment, the coverage of the anti-agglomeration wear-resistant surface layer is 65% of the outer surface area of ​​the calcined particles, and the average thickness of the anti-agglomeration wear-resistant surface layer is 15 μm.

[0099] In this embodiment, the calcium-containing reactive matrix includes a structural reinforcement phase, which is zirconium oxide, and the content of the structural reinforcement phase is 6 wt% of the total mass of the high-performance composite calcium-based thermochemical energy storage particles.

[0100] In this embodiment, the high-performance composite calcium-based thermochemical energy storage particles have a D50 particle size of 6 mm, a porosity of 30%, and at least some of the pores have a pore size of 30 μm.

[0101] Example 7 The preparation method of the high-performance composite calcium-based thermochemical energy storage particles of the present invention includes the following steps: 1) Mix the calcium source, thermally conductive reinforcing phase, structural reinforcing phase, pore-forming agent and binder to obtain a molding mixture; 2) The molding mixture is granulated by rounding to obtain green pellets; 3) The green particles are dried and calcined to remove the pore-forming agent and form a calcium-containing reactive matrix with interconnected pores to obtain calcined particles. 4) Spray coating is used to form an anti-agglomeration and wear-resistant surface layer on the surface of the calcined particles, resulting in coated particles; 5) The coated particles are activated to obtain high-performance composite calcium-based thermochemical energy storage particles.

[0102] In this embodiment, the calcium source is calcium carbonate.

[0103] In this embodiment, the pore-forming agent is selected from polyvinyl alcohol.

[0104] In this embodiment, the calcination includes a first stage of removing organic components and a second stage of calcination activation; the second stage calcination temperature is 1050℃ and the holding time is 10h.

[0105] In this embodiment, the activation treatment includes at least one carbonation-calcination cycle.

[0106] In this embodiment, the anti-agglomeration wear-resistant surface layer is made of composite inorganic particles of alumina and silicon oxide; the anti-agglomeration wear-resistant surface layer and the particle surface are cured by sol-gel.

[0107] The application of the high-performance composite calcium-based thermochemical energy storage particles in a thermochemical energy storage system, wherein the thermochemical energy storage system utilizes CaCO3 The reversible reaction of CaO+CO2 enables heat storage and release, and the high-performance composite calcium-based thermochemical energy storage particles are applied to fluidized bed reactors.

[0108] The high-performance composite calcium-based thermochemical energy storage particles contain 90 wt% calcium reactive matrix, 6 wt% thermally conductive reinforcing phase, and 4 wt% anti-agglomeration and wear-resistant surface layer.

[0109] In this embodiment, the anti-agglomeration and wear-resistant surface layer is composed of inorganic particles with a particle size of 2μm, and the inorganic particles are selected from ZrO2.

[0110] In this embodiment, the coverage of the anti-agglomeration wear-resistant surface layer is 55% of the outer surface area of ​​the calcined particles, and the average thickness of the anti-agglomeration wear-resistant surface layer is 5 μm.

[0111] In this embodiment, the calcium-containing reactive matrix includes a structural reinforcement phase, which is one or a combination of calcium aluminate, magnesium aluminum spinel, calcium silicate, zirconium oxide, magnesium oxide and aluminum oxide, and the content of the structural reinforcement phase is 4 wt% of the total mass of the high-performance composite calcium-based thermochemical energy storage particles.

[0112] In this embodiment, the high-performance composite calcium-based thermochemical energy storage particles have a D50 particle size of 1 mm, a porosity of 10% to 50%, and at least some of the pores have a pore size of 20 μm.

[0113] Example 8 The preparation method of the high-performance composite calcium-based thermochemical energy storage particles of the present invention includes the following steps: 1) Mix the calcium source, thermally conductive reinforcing phase, structural reinforcing phase, pore-forming agent and binder to obtain a molding mixture; 2) The shaped mixture is spray-granulated to obtain green pellets; 3) The green particles are dried and calcined to remove the pore-forming agent and form a calcium-containing reactive matrix with interconnected pores to obtain calcined particles. 4) Fluidized bed coating is used to form an anti-agglomeration and wear-resistant surface layer on the surface of the calcined particles, resulting in coated particles; 5) The coated particles are activated to obtain high-performance composite calcium-based thermochemical energy storage particles.

[0114] In this embodiment, the calcium source is dolomite.

[0115] In this embodiment, the pore-forming agent is selected as cellulose.

[0116] In this embodiment, the calcination includes a first stage of removing organic components and a second stage of calcination activation; the second stage calcination temperature is 800℃ and the holding time is 1h.

[0117] In this embodiment, the activation treatment includes at least one carbonation-calcination cycle.

[0118] In this embodiment, the anti-agglomeration wear-resistant surface layer is made of composite inorganic particles of alumina, silicon oxide and spinel; the anti-agglomeration wear-resistant surface layer is bonded to the particle surface by an inorganic binder.

[0119] The application of the high-performance composite calcium-based thermochemical energy storage particles in a thermochemical energy storage system, wherein the thermochemical energy storage system utilizes CaCO3 The reversible reaction of CaO+CO2 allows for heat storage and release, and the high-performance composite calcium-based thermochemical energy storage particles are applied to fixed-bed reactors, moving-bed reactors, fluidized-bed reactors, or gas-solid circulation reactors.

[0120] The high-performance composite calcium-based thermochemical energy storage particles contain 90 wt% calcium reactive matrix, 10 wt% thermally conductive reinforcing phase, and 10 wt% anti-agglomeration and wear-resistant surface layer.

[0121] In this embodiment, the anti-agglomeration and wear-resistant surface layer is composed of inorganic particles with a particle size of 5 μm, and the inorganic particles are selected from SiO2.

[0122] In this embodiment, the coverage of the anti-agglomeration wear-resistant surface layer is 80% of the outer surface area of ​​the calcined particles, and the average thickness of the anti-agglomeration wear-resistant surface layer is 30 μm.

[0123] In this embodiment, the calcium-containing reactive matrix includes a structural reinforcement phase, which is magnesium aluminum spinel, and the content of the structural reinforcement phase is 10 wt% of the total mass of the high-performance composite calcium-based thermochemical energy storage particles.

[0124] In this embodiment, the high-performance composite calcium-based thermochemical energy storage particles have a D50 particle size of 10 mm, a porosity of 50%, and at least some of the pores have a pore size of 50 μm.

[0125] Example 9 The preparation method of the high-performance composite calcium-based thermochemical energy storage particles of the present invention includes the following steps: 1) Mix the calcium source, thermally conductive reinforcing phase, structural reinforcing phase, pore-forming agent and binder to obtain a molding mixture; 2) The molding mixture is extruded and granulated to obtain green pellets; 3) The green particles are dried and calcined to remove the pore-forming agent and form a calcium-containing reactive matrix with interconnected pores to obtain calcined particles. 4) A dry mechanical coating method is used to form an anti-agglomeration and wear-resistant surface layer on the surface of the calcined particles, resulting in coated particles; 5) The coated particles are activated to obtain high-performance composite calcium-based thermochemical energy storage particles.

[0126] In this embodiment, the calcium source is limestone.

[0127] In this embodiment, the pore-forming agent is selected from starch.

[0128] In this embodiment, the calcination includes a first stage of removing organic components and a second stage of calcination activation; the second stage calcination temperature is 700℃ and the holding time is 0.5h.

[0129] In this embodiment, the activation treatment includes at least one carbonation-calcination cycle.

[0130] In this embodiment, the anti-agglomeration wear-resistant surface layer is made of composite inorganic particles of alumina and silicon oxide; the anti-agglomeration wear-resistant surface layer is bonded to the particle surface by electrostatic adsorption.

[0131] The application of the high-performance composite calcium-based thermochemical energy storage particles in a thermochemical energy storage system, wherein the thermochemical energy storage system utilizes CaCO3 The reversible reaction of CaO+CO2 enables heat storage and release, and the high-performance composite calcium-based thermochemical energy storage particles are applied to a fixed-bed reactor.

[0132] The high-performance composite calcium-based thermochemical energy storage particles contain 88 wt% calcium reactive matrix, 7 wt% thermally conductive reinforcing phase, and 5 wt% anti-agglomeration and wear-resistant surface layer.

[0133] In this embodiment, the anti-agglomeration and wear-resistant surface layer is composed of inorganic particles with a particle size of 10 nm, and the inorganic particles are selected from Al2O3.

[0134] In this embodiment, the coverage of the anti-agglomeration wear-resistant surface layer is 50% of the outer surface area of ​​the calcined particles, and the average thickness of the anti-agglomeration wear-resistant surface layer is 50 nm.

[0135] In this embodiment, the calcium-containing reactive matrix includes a structural reinforcement phase, which is one or more of calcium aluminate, magnesium aluminum spinel, calcium silicate, zirconium oxide, magnesium oxide and aluminum oxide, and the content of the structural reinforcement phase is 3 wt% of the total mass of the high-performance composite calcium-based thermochemical energy storage particles.

[0136] In this embodiment, the high-performance composite calcium-based thermochemical energy storage particles have a D50 particle size of 50 μm, a porosity of 10%, and at least some of the pores have a pore size of 0.05 μm.

[0137] Comparative Example 1 This comparative example uses ordinary limestone particles without added thermally conductive reinforcing phase and anti-agglomeration wear-resistant surface layer, prepared under the same molding, calcination and activation conditions as in Example 1.

[0138] Comparative Example 2 This comparative example uses particles that are only coated with SiO2 on the surface of ordinary limestone particles, without any internal thermally conductive or structurally reinforcing phases.

[0139] Performance testing methods Cyclic reaction performance: Multiple calcination / carbonation cycles were performed at a calcination temperature of 950℃ and a carbonation temperature of 700℃. The conversion rate was calculated using a thermogravimetric analyzer or by measuring the changes in CO2 concentration at the reactor inlet and outlet.

[0140] Thermal conductivity: The effective thermal conductivity of particle packing layers or pressed samples was determined by laser flash method, transient plane heat source method or steady state method.

[0141] Compressive strength: The maximum load during particle crushing was determined using a single-particle crushing strength tester.

[0142] Abrasion performance: The abrasion test device, such as a jet bed, fluidized bed or roller abrasion test device, is used to measure the fine powder generation rate or mass loss rate after a specified time.

[0143] Anti-agglomeration performance: The particle agglomeration rate, particle size distribution change and bed pressure drop fluctuation were tested under high temperature CO2 atmosphere or cyclic reaction conditions.

[0144] Microstructure: The surface distribution, phase composition, specific surface area and pore size distribution were characterized by SEM, EDS, XRD, BET and mercury porosimetry.

[0145] This invention has the following characteristics: Improved heat transfer capacity: A three-dimensional continuous heat conduction pathway is constructed inside the particles through a high thermal conductivity reinforcing phase, which reduces the thermal resistance of the calcium-based active matrix and decreases the temperature difference inside the particles during the reaction process.

[0146] Maintaining high reactivity: CO2 diffusion pathways are preserved through hierarchical interconnected channels and discontinuous surface layers, mitigating the adverse effects of dense coating on reaction kinetics.

[0147] Inhibits high-temperature agglomeration: The inorganic anti-agglomeration and wear-resistant surface layer on the outer surface prevents calcium-based particles from directly contacting each other, reduces the probability of sintering neck formation, and improves particle flowability.

[0148] Enhanced mechanical stability: The structurally reinforcing phase, internal thermally conductive skeleton, and anti-agglomeration wear-resistant surface layer work together to improve the particles' ability to withstand collisions, friction, thermal cycling stress, and phase change volume changes, thereby reducing the formation of fine powder.

[0149] Wide range of applications: The high-performance composite calcium-based thermochemical energy storage particles can be used for industrial waste heat storage, solar thermochemical energy storage, cogeneration peak shaving and high-temperature reactor thermal management.

[0150] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and disclosure of the invention. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0151] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

[0152] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing high-performance composite calcium-based thermochemical energy storage particles, characterized in that, include: 1) Mix the calcium source, thermally conductive reinforcing phase, structural reinforcing phase, pore-forming agent and binder to obtain a molding mixture; 2) The molding mixture is molded to obtain green pellets; 3) The green particles are dried and calcined to remove the pore-forming agent and form a calcium-containing reactive matrix with interconnected pores to obtain calcined particles. 4) An anti-agglomeration and wear-resistant surface layer is formed on the surface of the calcined particles to obtain coated particles; 5) The coated particles are activated to obtain high-performance composite calcium-based thermochemical energy storage particles.

2. The method for preparing high-performance composite calcium-based thermochemical energy storage particles according to claim 1, characterized in that, The calcium source is one or a combination of limestone, dolomite, calcium carbonate, calcium hydroxide, and calcium oxide.

3. The method for preparing high-performance composite calcium-based thermochemical energy storage particles according to claim 1, characterized in that, The pore-forming agent is selected from one or more of starch, cellulose, polyvinyl alcohol, polymethyl methacrylate, toner, and graphite powder.

4. The method for preparing high-performance composite calcium-based thermochemical energy storage particles according to claim 1, characterized in that, The calcination includes a first stage of removing organic components and a second stage of calcination activation; the second stage calcination temperature is 700℃-1050℃, and the holding time is 0.5h-10h.

5. The method for preparing high-performance composite calcium-based thermochemical energy storage particles according to claim 1, characterized in that, The activation treatment includes at least one carbonation-calcination cycle.

6. The method for preparing high-performance composite calcium-based thermochemical energy storage particles according to claim 1, characterized in that, The anti-agglomeration wear-resistant surface layer is made of composite inorganic particles of alumina and silica, or composite inorganic particles of alumina, silica and spinel; the anti-agglomeration wear-resistant surface layer is bonded to the particle surface by at least one of the following methods: electrostatic adsorption, inorganic binder bonding, sol-gel curing or sintering neck connection.

7. The method for preparing high-performance composite calcium-based thermochemical energy storage particles according to claim 1, characterized in that, The high-performance composite calcium-based thermochemical energy storage particles contain 80 wt% to 90 wt% of calcium reactive matrix, 3 wt% to 10 wt% of thermally conductive reinforcing phase, and 3 wt% to 10 wt% of anti-agglomeration and wear-resistant surface layer. The calcium-containing reactive matrix includes a structural reinforcing phase, which is one or a combination of calcium aluminate, magnesium aluminum spinel, calcium silicate, zirconium oxide, magnesium oxide and aluminum oxide, and the content of the structural reinforcing phase is 3 wt% to 10 wt% of the total mass of the high-performance composite calcium-based thermochemical energy storage particles.

8. The method for preparing high-performance composite calcium-based thermochemical energy storage particles according to claim 1, characterized in that, The coverage of the anti-agglomeration wear-resistant surface layer is 50% to 80% of the outer surface area of ​​the calcined particles, and the average thickness of the anti-agglomeration wear-resistant surface layer is 50nm-30μm.

9. A high-performance composite calcium-based thermochemical energy storage particle, characterized in that, It is prepared according to the preparation method of the high-performance composite calcium-based thermochemical energy storage particles according to any one of claims 1-8.

10. The application of the high-performance composite calcium-based thermochemical energy storage particles of claim 9 in a thermochemical energy storage system.

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