High-temperature heat storage element, high-temperature heat storage component and high-temperature heat storage devices each having at least one such high-temperature heat storage element, and industrial furnace having a high-temperature heat storage device
Patent Information
- Application Number
- AE202603078
- Authority / Receiving Office
- AE · AE
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2024-03-15
- Filing Date
- 2025-02-25
Smart Images
Figure ABST_ABST
Abstract
Description
High-Temperature heat storage element and high-temperature heat storage component, as well ashigh-temperature heat storage, respectively with at least one such high-temperature heat storage element, and industrial furnace with a high-temperature heat storageThe present invention relates to a high-temperature heat storage element for storing and recovering heat, preferably for a high-temperature heat storage, preferably a high-temperature heat storage for storing and recovering heat from power generation or from furnace exhaust gases of industrial furnaces, preferably in the form of a single or separate or isolated composite molded body, in particular in the form of a single or separate or isolated composite brick. Furthermore, the invention relates to a high-temperature heat storage component comprising at least one such high-temperature heat storage element, and a high-temperature heat storage comprising at least one such high-temperature heat storage element or at least one such high-temperature heat storage component, as well as an industrial furnace with such a high-temperature heat storage.High-temperature storages, or high-temperature heat storages, are a subgroup of heat storages. They are generally referred to as HTS (High Temperature Storage) or HTES (High Temperature Energy Storage). Systems operating at temperatures of 400°C or higher are classified as high-temperature heat storages.Heat storages are generally divided into two types: latent heat storages or latent heat storage systems and sensible heat storages. Latent heat storages utilize phase-change materials (PCM) or latent heat storage materials. Latent heat storages are also known as latent heat storage systems, phase-change storages or PCM storages.In latent heat storages, a large portion of the supplied thermal energy is stored in the form of conversion enthalpy (latent heat), for example, during a phase change from solid to liquid. The stored energy is latent because, as long as the phase change is not fully complete, the temperature of the material does not rise further despite the supply of heat.Sensible heat storages operate on the principle of temperature change in a storage material.High-temperature heat storages are used in a variety of applications, such as for storing thermal energy from industrial processes.In addition, high-temperature heat storages are used in sector coupling. In this process, excess electricity—particularly solar or wind power—is converted into heat and stored in the high-temperature heat storage. The virtually loss-free storage at temperatures typically ranging from 650 to 750 °C then enables the heat to be converted back into electricity via a steam turbine when there is a corresponding demand for electricity.WO 2018 / 170533 A1 discloses a high-temperature heat storage and recovery system comprising a layer for generating heat from electrical energy, a layer for storing the thermal energy, and a layer for recovering the thermal energy. The layer for storing thermal energy comprises one or more conical containers open at the top that contain a thermal storage material, such as a phase-change material. The upward-open, conically flaring shape and rounded corners allow the heat storage material to expand freely and reduce the stresses acting on the container.To protect the material of the conical containers and prevent leakage of the phase-change material, it is well known in the technical field to wrap the phase-change material with graphite paper. This is very labor-intensive.WO 2023 / 077194 A1 discloses a high-temperature heat storage element in the form of a molded body comprising a refractory material, a heat storage material, and an outer protective layer. The refractory material may be cement-bonded SiC, nitride-bonded SiC, silicon oxynitride-bonded SiC, clay-bonded SiC, SiAlON-bonded SiC, or -SiC-bonded SiC. The outer protective layer is a glassy protective layer made of an alkaline material. The heat storage material may be a phase-change material and is present in granular form.The high-temperature heat storage element is manufactured by mixing the individual components, in particular the refractory material, the heat storage material, and a protective layer material, with a liquid to form a slurry, pouring the slurry into a mold, allowing the slurry to harden to form the molded body, and heating the molded body. Heating then forms the protective layer as the refractory material oxidizes and reacts with the protective layer material.The protective layer is intended to prevent the heat storage material from leaking out of the high-temperature heat storage element. For this reason, the high-temperature heat storage element does not need to be housed in a container. However, it was discovered in the course of the invention that the protective layer cannot always reliably prevent the heat storage material from leaking.The term “refractory” in the context of the invention is not intended to be limited to the definition according to ISO 836 or DIN 51060, which define a pyrometric cone equivalent of > 1500 °C. Refractory products within the meaning of the invention have a refractoriness under load valueT0.5 according to DIN EN ISO 1893: 2008-09 of T0.5 ≥ 600 °C, preferably T0,5 ≥ 800 °C. Accordingly, refractory or fire-resistant granular materials or grainings in the sense of the invention are those materials or grainings which are suitable for a refractory product with the above-mentioned refractoriness under load value T0.5.Refractory products are used, among other things, for the protection of aggregate structures in aggregates where temperatures between 600 and 2000 °C, in particular between 1000 and 1800° C, predominate.Coarse ceramic products are known to be products produced from granular material with grain sizes of up to 6 mm, in special cases also up to 25 mm (see "Gerald Routschka / Hartmut Wuthnow, Praxishandbuch "Feuerfeste Werkstoffe", 6th edition, Vulkan-Verlag (hereinafter referred to simply as"Practical Handbook"), chapter 2).Coarse ceramics are distinguished from fine ceramics by the grain size of their structural components. If the structural components are at least partially larger than 1 mm, the product is a coarse ceramic product, if the structural components are exclusively ≤ 1 mm, it is a fine ceramic.In this context, the term "granular material" or "graining" within the meaning of the invention encompasses a pourable solid material consisting of many small, solid grains. If the grains have a grain size ≤ 200 µm, the granular material is a meal or powder. If the grains are produced by mechanical comminution, e.g. crushing and / or grinding, it is a crushed granular material or a broken granular material. However, a granular material may also comprise granular grains or pellet grains that are produced by granulating or pelletizing, respectively, without mechanical comminution. In addition, the broken granular material may also have a coating of another refractory material.The grain size distribution of the granular material is typically adjusted by sieving.Unless otherwise specified, the grain sizes specified within the context of this invention are determined in accordance with DIN 66165-2:2016-08.Furthermore, unless otherwise specified, the aggregates / granular materials used in the context of this invention are crushed, preferably uncoated, granular materials.In the context of the invention, grain fractions or grain classes have grain sizes between the two specified test grain sizes. The designation grain fraction or grain class thus means that no grains remain on the upper sieve and none fall through the lower sieve. There is therefore no oversize and no undersize grain.In contrast, the term "grain group" includes that some grains remain on the upper sieve (oversize grain) and some fall through the lower sieve (undersize grain).In addition, grain fractions or grain groups used in the field have grains of different sizes. They therefore have a grain distribution or grain size distribution. They are not single grain fractions or single grain groups.Furthermore, it is well known that refractory products are divided into non-basic (Practical Handbook, 4.1) and basic products (Practical Handbook, 4.2). According to DIN EN ISO 10081:2005-05, a distinction is made between non-basic and basic refractory products, based in particular on the chemical reaction behavior. The product group of non-basic products comprises the materials of the SiO2-Al2O3-series and other materials that cannot be further classified according to their chemical reaction behavior, such as SiC and carbon products. The essential characteristic of most basic products is that the sum of the oxides MgO and CaO predominates. In addition, chromite, picrochromite, spinel and forsterite bricks are attributed to the basic products, although they are almost neutral.Furthermore, in the case of coarse ceramic products, a further distinction is made between shaped and unshaped products.Shaped coarse ceramic products are unfired, tempered or ceramically fired products, preferably produced in a ceramic factory, in particular bricks or plates. They have a defined geometry and are ready for installation. Shaping is carried out, for example, by pressing, stamping, ramming or slip casting. The shaped products, in particular the bricks, are walled with mortar or without mortar ("crunch"), e.g. to form a lining. The production process of coarse ceramic shaped products is usually divided into the following steps (Practical Handbook, page 14 / item 2.1): PreparationMixingShapingDrying(if necessary) thermal treatment up to 800 °C and / or firingSubsequent treatment (if necessary)Unshaped products (Practical Handbook, page 142 / item 5) are products which, usually at the user's site, are formed into their final shape from an unshaped mass or from lumps, e.g. by casting, vibrating, poking, stamping or gunning. Unshaped products are usually placed behind formwork in larger fields at the place of use and, after hardening, form part of the lining. For example, unshaped products are gunning masses, stamping masses, casting masses, vibrating masses or grouting masses. Refractory mortars (fire mortars) are also classified as unshaped products.Silicon carbide materials, or SiC refractory materials, are described in the Practical Handbook, Chapter 4.1.5. The methods commonly used in ceramic process engineering are suitable for the manufacture of refractory products made of silicon carbide (SiC). However, due to the lack of sinterability of coarse silicon carbide granular materials, almost all SiC refractory materials are produced using bindings of a different type. A distinction is made between oxide or silicate bindings, nitrogen-containing binder systems, intrinsic SiC binding, and special types (see in particular the Practical Handbook, Table 4.10 A).Silicon carbide materials with a silicate binder matrix are produced using, among other things, clay as a binder. During firing, the clay reacts to form a binder phase consisting of mullite and SiO2.Silicon carbide materials with a nitrogen-containing binder system (=nitride-bonded SiC or nitride-bonded silicon carbide) comprise SiC grains or silicon carbide grains that are bonded together by a nitride-containing binder matrix. The binder matrix comprises the following binding phases: Si2ON2 (silicon oxynitride), Si3N4(silicon nitride), and / or SiAlON (silicon aluminum oxynitride).Refractory mortars are classified according to DIN EN 1402-1:2004-01 and DIN EN ISO 1927-1:2012-11 into heat-curing mortars, which set ceramically or chemically at elevated temperatures, and air-setting mortars, which harden chemically or hydraulically at room temperature. Refractory mortars always contain at least one type of refractory granular material, whereby the maximum grain size of the refractory granular materials contained in the mortars is preferably ≤ 1 mm (Practical Handbook, Chapter 5.9). The object of the present invention is to provide a high-temperature heat storage element that is simple and cost-effective to manufacture and install, comprises a long service life, and ensures high heat storage capacity.A further object is to provide a high-temperature heat storage component and a high-temperature heat storage, with at least one such high-temperature heat storage element.A further object is to provide an industrial furnace with such a high-temperature heat storage.In addition, a prefabricated high-temperature heat storage element component is to be provided for the manufacture of the high-temperature heat storage element.These objects are solved by a high-temperature heat storage element having the features of claim 1, a prefabricated high-temperature heat storage element component having the features of claim 35, a high-temperature heat storage component having the features of claim 36, a high-temperature heat storage having the features of claim 38, and an industrial furnace having the features of claim 39. Advantageous embodiments of the invention are described in the respective subsequent subclaims.The invention is explained in more detail below with reference to a drawing. The drawing shows:Figure 1: A schematic longitudinal section through a high-temperature heat storage element according to the inventionFigure 2: A schematic longitudinal section through a high-temperature heat storage component according to the invention, comprising multiple high-temperature heat storage elementsFigure 3: A schematic longitudinal section through a high-temperature heat storage component according to the invention comprising multiple high-temperature heat storage elements, in accordance with a further embodimentThe high-temperature heat storage element 1 (Figs. 1–3) of the invention is used for storing and recovering heat. It comprises an inner heat storage core 2 and a dimensionally stable outer shell 3 that surrounds the heat storage core 2 on all sides. An expansion joint 4 is provided between the heat storage core 2 and the outer shell 3, which is filled with a refractory expansion joint material 5. The high-temperature heat storage element 1 is preferably a single or separate, or isolated composite molded body, preferably a single or separate, or isolated composite brick. Preferably, the high-temperature heat storage element 1 is cuboid in shape and preferably comprises a p longitudinal direction 1a, a width direction 1b perpendicular thereto, and a height direction 1c perpendicular to both the longitudinal direction 1a and the width direction 1b.The, preferably cuboid, heat storage core 2 consists of at least one, preferably cuboid, molded core body 16, preferably a brick.The heat storage core 2 comprises an outer core surface 2a. The outer core surface 2a preferably comprises two opposing core side surfaces (not shown), two core end surfaces 6a perpendicular thereto, a core bottom surface 6b, and a core top surface 6c. The core bottom surface 6b and the core top surface 6c face each other in the height direction 1c.The at least one molded core body 16 comprises an molded body outer surface 16a. The molded body outer surface 16a preferably has two opposing molded body side surfaces (not shown), two molded body end surfaces 17a perpendicular thereto, a molded body bottom surface 17b, and a molded body top surface 17c. The molded body bottom surface 17b and the molded body top surface 17c face each other in the height direction 1c.If the heat storage core 2 consists of a single molded core body 16, which is preferred, the molded body outer surface 16a forms the outer core surface 2a. Accordingly, the molded body side surfaces form the core side surfaces, the molded body end surfaces 17a form the core end surfaces 6a, the molded body bottom surface 17b forms the core bottom surface 6b, and the molded body top surface 17c forms the core top surface 6c.However, the heat storage core 2 may also, in particular in the case of a larger high-temperature heat storage element 1, consist of several molded core bodies 16 joined together (Fig. 2). The molded core bodies 16 are joined directly to one another in such a way that they form the, preferably cuboid, heat storage core 2. In particular, the individual molded core bodies 16 are not connected to one another. In this case, the core outer surface 2a is respectively formed by portions of the molded body outer surfaces 16a of the individual molded core bodies 16.The heat storage core 2 primarily determines the heat storage capacity of the high-temperature heat storage element 1. Consequently, the heat storage core 2 must efficiently absorb and release heat. Furthermore, the heat storage core 2 should comprise uniform thermal expansion.The at least one molded core body 16 therefore comprises at least one refractory granular material of a refractory material as well as at least one granular material made of a phase-change material. Furthermore, the molded core body 16 comprises a binder matrix consisting of at least one hardened binder, which bonds the granular materials together. The granular materials are thus homogeneously distributed within the molded core body 16, particularly within the binder matrix.The fact that the molded core body 16 contains at least one refractory granular material means that it may also contain a mixture of different refractory granular materials.This applies in general to the phrase “at least one” within the context of this application. If at least one component may be present, this means, within the context of this application, that a mixture of various such components may also be present.Furthermore, the at least one refractory granular material of the molded body 16 preferably consists of a material with a thermal conductivity at 20°C, in accordance with DIN EN 993-15:2005-07, of 20 to 500 W / mK, preferably of 100 to 400 W / mK.In addition, the at least one refractory granular material of the core mold body 16 preferably comprises a softening point, in accordance with DIN EN 993-12:1997-06, of 1000 to 2500 °C, preferably of 1400 to 2300 °C.Preferably, the molded core body 16 comprises a refractory granular material of non-oxide ceramic, preferably of silicon carbide (SiC), and / or a refractory granular material of graphite, in particular flake graphite.The SiC granular material or refractory granular material of SiC may consist of a single raw material or multiple raw materials of silicon carbide (= silicon carbide raw material(s)). For example, the silicon carbide raw materials differ in terms of their SiC content. This also applies analogously to the other refractory granular materials.An advantage of the refractory SiC granular material is that it comprises a high thermal conductivity and is thermochemically stable. In particular, it is inert toward the phase-change material.The advantage of the, preferably mealy, refractory graphite granular material is that it also comprises a high thermal conductivity and is thermochemically stable. In addition, it ensures a dense structure and a smooth molded body outer surface 16a. If the molded body outer surface 16a is rough, coarse grains of the phase-change material are visible and touchable on the molded body outer surface 16a. This promotes the leakage of the phase-change material at high temperatures. In case of a smooth molded body outer surface 16a, the coarse grains are better embedded, and their exposed surface area is reduced. This significantly reduces the leakage of liquid phase-change material at temperatures above the phase-change material’s melting point.Furthermore, the at least one granular material of refractory material, in particular the SiC granular material, preferably comprises a grain size of ≤ 2.0 mm, more preferably ≤ 1.5 mm, and most preferably ≤ 1.0 mm.And the granular material of graphite preferably comprises a grain size of ≤ 200 µm, more preferably ≤ 150 µm.Particularly advantageously the molded core body 16 comprises an SiC granular material and a granular material of graphite. However, it may also comprise exclusively a SiC granular material or exclusively a granular material of graphite.Preferably, the molded core body 16 comprises a coarse-grain fraction with a grain size > 1.0 mm, a fine-grain fraction with a grain size of > 200 µm to ≤ 1.0 mm, and a meal-grain fraction with a grain size ≤ 200 µm.Preferably, the molded core body 16 comprises an SiC content of 5 to 65 ma.-% (mass-%), preferably 10 to 30 ma.-%, and most preferably 15 to 20 ma.-%, determined in accordance with DIN EN ISO 21068-2:2008-12. Preferably, the molded core body 16 also comprises a carbon content of 2 to 65 ma.-%, preferably 10 to 25 ma.-%, and most preferably 12 to 17 ma.-%, determined in accordance with DIN EN ISO 21068-2:2008-12.The at least one phase-change material is preferably a metallic material, more preferably a metal alloy.The phase-change material also preferably comprises a melting point of > 250 °C, preferably > 1000 °C, and more preferably > 1050 °C, as determined by differential scanning calorimetry (DSC) in accordance with DIN 51007:2019-04.Preferably, the at least one phase-change material is a silicon-based, eutectic metallic material, more preferably an aluminum-silicon-nickel alloy.Furthermore, the at least one granular material of phase-change material preferably comprises a grain size of 0.06 mm to 12 mm, preferably 1 mm to 6 mm. The granular material of phase-change material preferably always contains a coarse-grain fraction.Preferably, the molded core body 16 comprises a phase-change material content of 30 to 97 ma.-%, preferably 50 to 70 ma.-%, determined in accordance with DIN EN 13925-2:2003-07 using the Rietveld method and without an internal standard. The binder matrix of the molded core body 16 contains at least one set, permanent, and / or temporary binder.A permanent binder is a binder that hardens below the temperature required for ceramic firing but, when subjected to thermal stress, in particular in an O2 atmosphere, does not volatilize but rather transforms and forms a binding matrix with a ceramic or other type of bond. Permanent binders thus ensure the cohesion of an unfired molded body at room temperature as well as during use under thermal stress, particularly in an O2 atmosphere. In contrast, a temporary binder burns out and volatilizes when subjected to thermal stress. Permanent binders harden at a temperature below that required for ceramic firing, for example at room temperature, hydraulically, chemically (inorganically or organo-inorganically), or organically. Under thermal stress, they form a direct ceramic bond, for example through sintering. Phosphate and cement bonds, for instance, undergo transformation under thermal stress but remain intact. Synthetic resins are generally thermosetting at approximately 160–200 °C. At temperatures of approximately 600 °C or higher, pyrolysis occurs and the synthetic resin bond is converted into a carbon bond.Preferably, the at least one binder is a coking binder, preferably a synthetic resin, tar, or pitch, and most preferably a synthetic resin. Coking binders form a coke framework after coking in a manner known per se. The coke framework ensures a certain degree of strength of the heat storage core 2 even after exposure of the heat storage core 2 to heat and the resulting coking of the binder. In addition, carbon comprises a high thermal conductivity.Another advantage of the coking binders, particularly the synthetic resin, is that they ensure good pressing properties of the press mass during the manufacture of the heat storage core 2, since only a small amount of liquid is required. As a result, the pressed heat storage core 2 comprises low porosity and thus good thermal conductivity.The coking binders, particularly the synthetic resin, also ensure good green strength and rapid strength development.However, the binder can also be an inorganic binder, preferably water glass, a sol-gel binder, a phosphate binder, alumina cement, or Portland cement.Furthermore, the molded core body 16 preferably comprises a heat storage capacity of 200 to 2500 kJ / kg, preferably 800 to 1800 kJ / kg, as determined by differential scanning calorimetry (DSC) in accordance with DIN 51007:2019-04.In addition, the molded core body 16 preferably comprises a cold compressive strength in accordance with DIN EN 993-6:2019-3 of 5 to 250 MPa, preferably 20 to 50 MPa, determined on a test cylinder with a diameter of 36 mm and a height of 36 mm.Furthermore, the molded core body 16 preferably comprises a porosity in accordance with DIN EN 993-1:2019-03 of 0.5 to 15 vol.-%, preferably 5 to 8 vol.-%, and more preferably 6 to 7 vol.-%.Furthermore, the molded core body 16 preferably comprises a dry raw density in accordance with DIN EN 993-1:2019-03 of 1.5 to 5 g / cm3, preferably 2.5 to 3.5 g / cm3, and more preferably 3.1 to 3.3 g / cm3.Preferably, the molded core body 16 also comprises a thermal conductivity at 200°C of 10 to 100 W / mK, preferably 15 to 30 W / mK, and / or of 5 to 100 W / mK, preferably 15 to 30 W / mK, at 600°C and / or of 5 to 100 W / mK, preferably 15 to 30 W / mK, at 1000°C as determined in accordance with DIN EN ISO 1893:2008-09.Preferably, the molded core body 16 is also an unfired and, if necessary, tempered, preferably pressed, molded body. This is advantageous because the phase-change material is not exposed to high temperatures prior to the use of the high-temperature heat storage element 1, which could lead to deformation of the molded core body 16. For this reason, the amount of phase-change material in the molded core body 16 can also be high. Furthermore, this ensures that the phase-change material is exposed to high temperatures only when it is located inside the outer shell 3 and is thus protected from the atmosphere. This prevents oxidation of the phase-change material.The molded core body 16 is manufactured in a manner known per se from a refractory batch. The batch contains, in a manner known per se, a dry material mixture as well as, if applicable, liquid batch components. The dry material mixture comprises the at least one refractory granular material and the at least one granular material out of phase-change material. In addition, the batch comprises at least one binder in liquid or in solid form, therefore in this case as part of the dry material mixture.The amount of coarse-grain fraction in the dry material mixture is preferably 40 to 90 ma.-%, and / or the amount of fine-grain fraction is preferably 5 to 50 ma.-%, and / or the amount of meal-grain fraction is preferably 5 to 40 ma.-%.In addition, the dry material mixture preferably contains an amount of phase-change material of 30 to 99 ma.-%, preferably 50 to 70 ma.-%.For the production of the pressed molded core body 16, in particular the core brick, a fresh batch mass or moldable mass, specifically a pressing mass, is prepared from the batch components and, if applicable, water. The fresh batch mass or press mass thus comprises at least one binder, at least one refractory granular material, and the at least one granular material out of phase-change material. Depending on requirements, water is also used to prepare the press mass. If the press mass contains a liquid binder and / or other liquid components, the addition of water is not necessary but is possible. However, water alone may also be added.To ensure optimal mixing of the individual batch components, mixing is carried out for 3 to 10 minutes, for example.The press mass is placed in molds and pressed to form a green molded body. The pressing pressures are within the usual ranges, e.g., 50 to 200 MPa, preferably 100 to 180 MPa.Preferably, the molded core body 16 is dried and / or tempered after pressing. When tempering, prior drying is generally omitted.Drying is preferably carried out at a temperature between 80 and 130 °C, particularly between 100 and 120 °C. Drying is preferably carried out until a residual moisture content of between 0 and 2 ma.-%, particularly between 0 and 1 ma.-%, is achieved, as determined in accordance with DIN 51078:2002-12.Tempering is preferably carried out at a temperature between 150 and 300 °C, particularly between 200 and 250 °C, and / or for a duration of 3 to 72 hours, preferably 5 to 24 hours.The dried, pressed, unfired, and, if applicable, tempered molded core body 16, in particular the core brick, is then used to manufacture the high-temperature heat storage element 1 according to the invention.Another advantage of the heat storage core 2 made from the at least one unfired and, if applicable, merely tempered molded core body 16 is that it can be manufactured easily and with minimal energy consumption. The manufacturing process by pressing ensures high density and thus high thermal conductivity. In addition, large quantities can be produced in a short time.However, it is also within the scope of the invention to fire the molded core body 16 ceramically. For firing, the, preferably dried, pressed core molded body 16 is fired in a ceramic furnace, e.g., a tunnel kiln, preferably at temperatures between 1200 and 1800 °C, particularly between 1400 and 1700 °C. Preferably, the firing is carried out under reducing conditions.However, as already explained above, it is particularly advantageous if the molded core body 16 is not ceramically fired.The molded core body 16 may also be shaped by other conventional methods, preferably by casting, in particular slip casting, into a mold, or by an extrusion process using a plastic mixture, or by manual or mechanical stamping or ramming. In casting, particularly slip casting, the mixture prepared from the batch components is accordingly fluid.However, shaping by pressing is preferred for the reasons mentioned above.The outer shell 3 of the high-temperature heat storage element 1 according to the invention serves to protect the heat storage core 2 from the surrounding atmosphere. It must comprise high resistance to oxidizing and reducing gases and high resistance to thermal cycling. In addition, the outer shell 3 provides the high-temperature heat storage element 1 with mechanical stability, particularly during operation. To ensure efficient energy input and output from the high-temperature heat storage or another application site, the outer shell 3 must also comprise a high thermal conductivity.The outer shell 3 is preferably formed from at least two parts from at least two outer shell components 3a;b and preferably comprises a crucible 7 for housing the heat storage core 2 and a lid 8 that closes off the crucible 7.The crucible 7 is a vessel or container open on one side, specifically to the top. It comprises a crucible wall 9 with two crucible side walls (not shown), two crucible end walls 10a perpendicular thereto, and a crucible bottom wall 10b. In addition, the crucible wall 9 comprises a crucible wall outer surface 9a, a crucible wall inner surface 9b, and a crucible wall edge surface 9c.The crucible side walls and / or the crucible end walls 10a and / or the crucible bottom wall 10b also preferably each comprise a wall thickness of 3 to 60 mm, preferably 8 to 15 mm.The lid 8 is preferably plate-shaped and comprises a lid bottom surface 8a, a lid top surface 8b, and four lid edge surfaces 8c that are adjacent in pairs.Preferably, the lid 8 also comprises a central centering projection 11 on the lid bottom surface 8a. The centering projection 11 transitions via a chamfer 12 into a circumferential lid support surface 13.The lid 8 also preferably comprises a thickness (=the maximum distance between the lid bottom surface 8a and the lid top surface 8b) of 3 to 60 mm, preferably 8 to 15 mm.The lid 8 and the crucible 7 are respectively made of a refractory, preferably coarse ceramic material. Consequently, the lid 8 and the crucible 7 respectively comprise at least one refractory granular material. Preferably, the lid 8 and the crucible 7 are made of the same material. Furthermore, each is a molded body or a molded refractory product.Furthermore, the at least one refractory granular material of the lid 8 and / or the crucible 7 preferably comprises a softening point according to DIN EN 993-12:1997-06 of 1000 to 2500 °C, preferably of 1400 to 2300 °C.Preferably, the material of the lid 8 and / or the crucible 7 comprises an SiC granular material.Preferably, the lid and the crucible contain SiC in an amount of 50 to 98 ma.%, more preferably 75 to 90 ma.%, and more preferably 80 to 85 ma.%, as determined in accordance with DIN EN ISO 21068-2:2008-12.One advantage of SiC is that it forms a protective SiO2 layer in an oxidizing atmosphere.Furthermore, the crucible 7 and the lid 8 preferably contain no phase-change material.Preferably, the lid 8 and the crucible 7 are also made of ceramically fired material. The shaping is preferably carried out, as described above for the heat storage core 2, by pressing out of a refractory batch. The molded bodies are then dried and subsequently ceramically fired. Of course, the shaping can also be carried out here in other ways as described above, preferably by casting.When the lid 8 and the crucible 7 are ceramically fired, this has the advantage that, during the initial heating of the high-temperature heat storage element 1 according to the invention in use, no drying shrinkage or firing shrinkage occurs, which would lead to an irreversible change in length. In addition, firing results in good physical properties, in particular high strength and low porosity.In particular, the lid 8 and the crucible 7 consist of a silicon carbide material, preferably a silicon carbide material with a ceramic, preferably silicate, binding or with a nitride binding.However, a different binder may also be used to manufacture the lid 8 and the crucible 7, such as cement, a phosphate binder, or a coking binder.Depending on the application and the atmosphere prevailing during that application, the lid 8 and the crucible 7 may also be made of a different refractory material to protect the heat storage core 2, preferably of silicon nitride or a material of the SiO2-Al2-O3 series, in particular a mullite-containing material, or from MA spinel or a cordierite-containing material.Materials in the SiO2-Al2-O3 series are materials whose aggregates consist primarily of Al2-O3(alumina), SiO2, and aluminosilicates. These may include, in particular, silica materials, corundum materials, or materials out of aluminosilicates. Preferably, these are chamotte materials (≤ 45 ma.-% Al2-O3) or alumina-rich materials (> 45 ma.-% Al2-O3).Preferably, the lid 8 and the crucible 7 also comprise a raw density according to DIN EN 993-1:2019-3 of 1.5 to 3.0 g / cm3, preferably 2.0 to 2.5 g / cm3, and more preferably 2.1 to 2.2 g / cm3.In addition, the lid 8 and the crucible 7 preferably comprise a porosity according to DIN EN 993-1:2019-3 of 5 to 40 vol.-%, preferably 15 to 30 vol.-%, and more preferably 20 to 25 vol.-%.Furthermore, the lid 8 and the crucible 7 preferably comprise a cold compressive strength in accordance with DIN EN 993-5:2019-3 of 30 to 150 MPa, preferably 50 to 100 MPa, determined on a test cylinder with a diameter of 36 mm and a height of 8 mm.Furthermore, the lid 8 and the crucible 7 preferably comprise a thermal shock resistance (TSR) of > 30 cycles, preferably > 70 cycles, determined in accordance with DIN 51068:2008-11 using water quenching.Furthermore, the lid 8 and / or the crucible 7 preferably comprise a thermal expansion at 1000 °C, as determined in accordance with DIN EN ISO 1893-2008-9, of 0 to 2 %, preferably 0 to 1 %.Preferably, the lid 8 and / or the crucible 7 also comprise a thermal conductivity of 10 to 20 W / mK, preferably 15 to 17 W / mK, at 800°C and / or of 8 to 18 W / mK, preferably 13 to 15 W / mK, at 1000°C and / or of 6 to 16 W / mK, preferably 11 to 13 W / mK, at 1200°C as determined in accordance with DIN EN ISO 1893:2008-09.As previously explained, the expansion joint 4, filled with the expansion joint material 5, is located between the heat storage core 2 and the outer shell 3. The expansion joint 4 and the expansion joint material 5 surround the heat storage core 2 on all sides.The expansion joint 4 and the expansion joint material 5 serve to compensate for the different thermal expansions of the heat storage core 2 and the outer shell 3 during operation. This prevents stresses and / or cracks caused by differences in expansion between the heat storage core 2 and the outer shell 3. This is because the expansion joint material 5 shrinks, thereby providing space for the expansion of the heat storage core 2. The expansion joint material 5 does not expand in volume during operation. The thermal conductivity of the expansion joint material 5 should be as high as possible. It is essential that the expansion joint material 5 completely fills the expansion joint 4 and that no air (insulation) is present.On the one hand, the expansion joint 4 should be as thin or narrow as possible so as not to impair the thermal conductivity of the high-temperature heat storage element 1, on the other hand, it must be sufficiently wide to ensure adequate space for expansion compensation.Preferably, the expansion joint 4 has a joint width of 0.1 to 5 %, preferably 0.5 to 2.0 %, of the dimension of the heat storage core 2 in the respective direction 1a;b;c. In the longitudinal direction 1a, the expansion joint 4 thus has a joint width corresponding to 0.1 to 5 %, preferably 0.5 to 2.0 %, of the length of the heat storage core 2 in the longitudinal direction 1a. This applies analogously to the other two directions 1b;c.The expansion joint material 5 also preferably serves to join, in particular, to bond, the heat storage core 2 and the outer shell 3 into a stable high-temperature heat storage element 1, especially during operation. The expansion joint material 5 must also be sufficiently soft or elastic to compensate for the different expansions of the heat storage core 2 and the outer shell 3.Preferably, the expansion joint material 5 is a set or hardened refractory mortar.In this case, the expansion joint material 5 comprises a binder matrix that comprises at least one chemically or hydraulically hardened binder.In addition, the expansion joint material 5 comprises at least one refractory granular material embedded in the binder matrix.The at least one refractory granular material preferably consists of silicon carbide (SiC) or corundum (Al2O3) or an aluminosilicate or quartz (SiO2) or carbon (C), preferably graphite.The at least one refractory granular material of the expansion joint material 5 also preferably consists of a material with a thermal conductivity at 20°C of 5 to 500 W / mK, preferably of 30 to 400 W / mK, in accordance with DIN EN 993-15:2005-07,.In addition, the at least one refractory granular material of the expansion joint material 5 preferably comprises a softening point, in accordance with DIN EN 993-12:1997-06, of 1000 to 2500 °C, preferably 1400 to 2300 °C.Furthermore, the at least one granular material made of refractory material, in particular the SiC granular material, preferably comprises a particle size of < 1.5 mm, preferably < 1.0 mm.Preferably, the expansion joint material 5 has an SiC content of 40 to 95 ma.%, preferably 70 to 90 ma.%, and most preferably 83 to 86 ma.%.According to a further embodiment, the expansion joint material is a loose fill consisting of at the least one refractory granular material. The loose fill also provides for expansion compensation.To manufacture the high-temperature heat storage element 1 according to the invention, the fresh, not yet hardened expansion joint material 5 is first poured into the crucible 7. The heat storage core 2, in the form of at least one molded core body 16, is then inserted into the crucible 7 such that the core outer surface 2a is spaced apart from the crucible wall inner surface 9b . This forms the expansion joint 4 between the core outer surface 2a and the crucible wall inner surface 9b. The core top surface 6c is positioned slightly lower than the crucible wall edge surface 9c. The heat storage core 2 is thus recessed within the crucible 7.After that, the expansion joint 4 is further filled with the expansion joint material 5, and the core top surface 6c is coated with the expansion joint material 5 and the surface is smoothed. The lid 8 is then placed on the crucible 7. In doing so, the centering projection 11 of the lid 8 is inserted into the crucible 7 with a positive fit, and the lid support surface 13 is placed on the crucible wall edge surface 9c. If necessary, some expansion joint material 5 is pressed between the lid support surface 13 and the crucible wall edge surface 9c. The high-temperature heat storage element 1 is then allowed to dry, preferably at a temperature of 80 to 130°C, more preferably 100 to 120°C, for 3 to 24 hours, more preferably 5 to 15 hours, wherein the expansion joint material 5 hardens. Crucible 7, lid 8, and heat storage core 2 are then firmly connected to each other via the hardened expansion joint material 5.If the expansion joint material 5 consists of loose fill, hardening is omitted.Preferably, the produced high-temperature heat storage element 1 also comprises a length of 60 to 1500 mm, preferably 200 to 500 mm, a width of 60 to 1000 mm, preferably 100 to 400 mm, and a height of 60 to 1000 mm, preferably 75 to 250 mm.An advantage of the high-temperature heat storage element 1 according to the invention is that it can be used at high operating temperatures. In addition, it comprises a high thermal conductivity due to the high amount of phase-change material. The high-temperature heat storage element 1 of the invention is also resistant to thermal shock and changing atmospheres. It can be produced on an industrial scale and, due to its modular design, can be used flexibly.In particular, in use, a plurality of high-temperature heat storage elements 1 are preferably assembled into a high-temperature heat storage component 11 (Figs. 2;3). The high-temperature heat storage elements 1 are then arranged side by side and on top of one another and preferably form a high-temperature heat storage wall 12. In particular, the high-temperature heat storage elements 1 are thus arranged side by side and on top of one another in the manner of bricks.According to one embodiment of the invention (Fig. 3), the high-temperature heat storage elements 1 do not have a separate lid 8, but rather the outer shell 3 of the respective lower high-temperature heat storage element 1 is formed by the crucible 7 of the lower high-temperature heat storage element 1 and by the respective crucible bottom wall 10b of the high-temperature heat storage element(s) 1 arranged above it. This has the advantage of improving the heat conduction from one heat storage core 2 to another, since there is less other material in between. Nevertheless, the heat storage cores 2 are all surrounded on all sides by an outer shell 3 and are thereby protected from the atmosphere. Consequently, other arrangements and configurations of the outer shell 3 are also possible within the scope of the invention, as long as the heat storage cores 2 are all surrounded on all sides by an outer shell 3.Within the scope of the invention, it is also possible, for example, for the outer shell 3 to be formed from more than two outer shell components 3a;b. In addition, the outer shell 3 may, for example, also be formed as two half-shells that are joined together to form the closed outer shell 3. The outer shell 3 is thus formed from at least two outer shell components 3a;b.Furthermore, as described, it is particularly advantageous if the high-temperature heat storage element 1 is formed as a high-temperature heat storage brick comprising the crucible 7, the heat storage core 2, the expansion joint material 5, and the lid 8. This is because the high-temperature heat storage element 1 can then be prefabricated and transported as such to the respective site of use. However, it is of course also possible to assemble the individual components of the high-temperature heat storage element 1 only at the installation site or to transport a prefabricated high-temperature heat storage element component consisting of the crucible 7, the heat storage core 2, and the expansion joint material 5, in particular the refractory mortar, without the lid 8, in particular a brick, to the site of use.The high-temperature heat storage according to the invention serves, in a manner known per se, to store and recover energy from various processes, e.g., from electricity generation, in particular from wind power or solar energy. In this case, the high-temperature heat storage includes electric heating elements for heating the high-temperature heat storage elements 1. Heat recovery then takes place through wind heating and, if applicable, power generation. The high-temperature heat storage elements 1 can also be heated by hot exhaust gas streams, in particular by furnace exhaust gases from industrial furnaces, especially furnaces in the iron industry, the non-ferrous metal industry, or firing furnaces in the non-metallic industry, preferably cement kiln plants, lime shaft kilns, or rotary lime kilns, magnesite or dolomite kilns, or kilns of waste incineration plants. Exemplary embodiment:1. Manufacture of the moldedcore body for the heat storage coreTable 1: Batch composition (dry batch components or dry material mixture) for the production of the molded core bodyraw material namepropertiesgrain groupamount in ma.-%PCMAlSiNi, Tmelt: 1079 °C3.0–5.0 mm27.5PCMAlSiNi, Tmelt: 1079 °C1.0–3.0 mm37.5SiC 98SiC > 98.5 ma.-%0.5–1.0 mm5.0SiC 98SiC > 98.5 ma.-%0.2–0.5 mm6.5SiC 98SiC > 98.5 ma.-%0–0.06 mm8.0graphiteC > 94.0 ma.-% 0.1–0.5 mm15.5 The dry batch components were mixed with 3.5 ma. % phenol-formaldehyde resin, based on the dry batch components, to form a press mass. The press mass was then compacted by uniaxial pressing at a pressing pressure of 140 MPa and pressed into a green molded core body (brick) with the following dimensions: 230 x 114 x 76 mm3.The pressed green molded core body was then tempered at 250 °C for 24 h.2. Manufacture of the crucible and lidTable 2: Batchcomposition (dry batch components or dry material mixture) for the production of the crucible and the lidraw material namepropertiesgrain groupamount in ma.-%SiC 98SiC > 98.5 ma. %1 – 2 mm20SiC 98SiC > 98.5 ma.%0.2 – 0.5 mm30SiC 98SiC > 98.5 ma.%0 – 0.2 mm35clayAl2O3 > 40 ma.%≤ 200 µm10aluminaAl2O3 > 97 ma.%≤ 200 µm5 The theoretical chemical composition of the batch, including the binder, is 85 ma.% SiC, 8.2 ma.%Al2O3, 6.5 ma.% SiO2, and 0.3 ma.% Fe2O3.The dry batch components were mixed with a liquid binder in the form of sulfite lye to form a batch fresh mass or press mass. The amount of liquid binder was 1.0 ma.% relative to the dry material mixture. Among other things, the liquid binder served to increase green strength.The press mass was respectively compacted by uniaxial dry pressing to form a green body. The pressing pressure was 120 MPa.The green molded bodies were then dried at 110 °C for 12 h to a residual moisture content of < 0.5 %, and the dried molded bodies were fired under oxidizing conditions at 1430 °C for 8 h in an electrically heated muffle furnace. 3. Manufacture of the high-temperature heat storage elementThe refractory mortar REFRABOND S-85 R from Refratechnik Steel GmbH was used as the expansion joint mortar, with the following properties: Table 3: Properties of the expansion joint mortar usedproperties amount in ma.%chemical compositionSiC 85.5 Al2O3 5.5 SiO2 8.3 CaO 0.1 Fe2O3 0.6binderclay maximum grain size0.8 mm The fresh mortar mixture was poured into the crucible, and then the molded core body was placed in the crucible such that the molded body outer surface is spaced apart from the crucible wall inner surface and the molded core body is recessed within the crucible. This created the expansion joint between the molded body outer surface and the crucible wall inner surface.The expansion joint was then further filled with expansion joint mortar, and the molded body top surface was coated with expansion joint mortar and smoothed. The lid was then placed on the crucible. In doing so, the centering protrusion of the lid was inserted into the crucible with a form-fit, and the lid support surface was placed on the crucible wall edge surface 9c. Subsequently, the produced high-temperature heat storage element was dried at 110°C for 12 hours.The outer dimensions of the produced high-temperature heat storage element were: 254 x 137 x 99 mm.Finally, it should be noted that all of the mentioned features, in particular the claimed features, of the high-temperature heat storage element and the high-temperature heat storage, taken individually and in any combination, are particularly advantageous and constitute the subject matter of the present invention.Furthermore, the upper and lower limits specified for each range can all be combined with one another in accordance with the invention.
Claims
1. A high-temperature heat storage element (1) for storing and recovering heat, preferably for a high-temperature heat storage, more preferably for a high-temperature heat storage for storing and recovering heat from power generation or from furnace exhaust gases of industrial furnaces, comprising an inner heat storage core (2) and a refractory outer shell (3) surrounding the heat storage core (2) on all sides, wherein an expansion joint (4) filled with a refractory expansion joint material (5) is provided between the heat storage core (2) and the outer shell (3), wherein the heat storage core (2) consists of at least one molded core body (16), wherein the molded core body (16) comprises at least one refractory granular material, at least one granular material made of a phase-change material, and a binder matrix comprising at least one hardened binder, which connects the granular materials to each other.
2. High-temperature heat storage element (1) according to claim 1,characterized in thatthe at least one molded core body (16) is unfired and preferably tempered. 3. High-temperature heat storage element (1) according to claim 1 or 2,characterized in thatthe outer shell (3) consists of ceramically fired refractory material. 4. High-temperature heat storage element (1) according to one of the preceding claims,characterized in thatthe high-temperature heat storage element (1) is designed as a composite brick and is preferably cuboid in shape. 5. High-temperature heat storage element (1) according to one of the preceding claims,characterized in thatthe binder matrix of the at least one molded core body (16) comprises at least one hardened, coking binder, preferably hardened synthetic resin and / or tar and / or pitch. 6. High-temperature heat storage element (1) according to one of the preceding claims,characterized in thatthe at least one molded core body (16) comprises a phase-change material content of 30 to 97 ma.%, preferably 50 to 70 ma.%, determined in accordance with DIN EN 13925-2:2003-07 using the Rietveld method and without an internal standard. 7. High-temperature heat storage element (1) according to one of the preceding claims,characterized in thatthe at least one refractory granular material of the at least one molded core body (16) consists of a material having a thermal conductivity at 20 °C, according to DIN EN 993-15:2005-07, of 20 to 500 W / mK, preferably 100 to 400 W / mK. 8. High-temperature heat storage element (1) according to one of the preceding claims,characterized in thatthe at least one refractory granular material of the at least one molded core body (16) comprises a softening point, in accordance with DIN EN 993-12:1997-06, of 1000 to 2500 °C, preferably 1400 to 2300 °C. 9. High-temperature heat storage element (1) according to one of the preceding claims,characterized in thatthe at least one molded core body (16) comprises a refractory granular material made of non-oxide ceramics, preferably SiC, and / or a refractory granular material made of graphite. 10. High-temperature heat storage element (1) according to one of the preceding claims,characterized in thatthe at least one molded core body (16) comprises an SiC content of 5 to 65 ma.%, preferably 10 to 30 ma.%, and more preferably 15 to 20 ma.%, determined in accordance with DIN EN ISO 21068-2:2008-12. 11. High-temperature heat storage element (1) according to one of the preceding claims,characterized in thatthe at least one molded core body (16) comprises a carbon content of 2 to 65 ma.%, preferably 10 to 25 ma.%, most preferably 12 to 17 mass-%, determined in accordance with DIN EN ISO 21068-2:2008-12. 12. High-temperature heat storage element (1) according to one of the preceding claims,characterized in thatthe at least one molded core body (16) comprises a heat storage capacity of 200 to 2500 kJ / kg, preferably 800 to 1800 kJ / kg, determined by differential scanning calorimetry (DSC) in accordance with DIN 51007:2019-04. 13. High-temperature heat storage element (1) according to one of the preceding claims,characterized in thatthe at least one molded core body (16) comprises a cold compressive strength according to DIN EN 993-6:2019-3 of 5 to 250 MPa, preferably 20 to 50 MPa, determined on a test cylinder with a diameter of 36 mm and a height of 36 mm. 14. High-temperature heat storage element (1) according to one of the preceding claims,characterized in thatthe at least one molded core body (16) comprises a porosity according to DIN EN 993-1:2019-3 of 0.5 to 15 vol.%, preferably 5 to 8 vol.%, and more preferably 6 to 7 vol.%. 15. High-temperature heat storage element (1) according to one of the preceding claims,characterized in thatthe at least one molded core body (16) comprises a dry raw density according to DIN EN 993-1:2019-03 of 1.5 to 5 g / cm3, preferably 2.5 to 3.5 g / cm3, and more preferably 3.1 to 3.3 g / cm3. 16. High-temperature heat storage element (1) according to one of the preceding claims,characterized in thatthe at least one molded core body (16) comprises a thermal conductivity of 10 to 100 W / mK, preferably 15 to 30 W / mK, at 200°C and / or of 5 to 100 W / mK, preferably 15 to 30 W / mK, at 600°C and / or of 5 to 100 W / mK, preferably 15 to 30 W / mK, at 1000°C, as determined in accordance with DIN EN ISO 1893:2008-09. 17. High-temperature heat storage element (1) according to one of the preceding claims,characterized in thatthe at least one granular material of phase-change material consists of a metallic material, preferably a metal alloy, and more preferably an aluminum-silicon-nickel alloy. 18. High-temperature heat storage element (1) according to one of the preceding claims,characterized in thatthe phase-change material comprises a melting point of > 250 °C, preferably > 1000 °C, and more preferably > 1050 °C, as determined by differential scanning calorimetry (DSC) in accordance with DIN 51007:2019-04. 19. High-temperature heat storage element (1) according to one of the preceding claims,characterized in thatthe at least one molded core body (16) is a pressed molded body. 20. High-temperature heat storage element (1) according to one of the preceding claims,characterized in thatthe outer shell (3) is formed in at least two parts from at least two outer shell components (3a;b). 21. High-temperature heat storage element (1) according to claim 20,characterized in thatthe outer shell (3) comprises a refractory, preferably fired, crucible (7) and, preferably, a refractory, preferably fired, lid (8) that closes off the crucible (7), wherein the crucible (7) and the lid (8) are preferably firmly connected to one another and the heat storage core (2) is arranged within the crucible (7). 22. High-temperature heat storage element (1) according to claim 21,characterized in thatthe crucible (7) comprises a crucible wall (9) with two crucible side walls, two crucible end walls (10a) perpendicular thereto, and a crucible bottom wall (10b). 23. High-temperature heat storage element (1) according to claim 21 or 22,characterized in thatthe lid (8) is plate-shaped and preferably comprises a lid bottom surface (8a), a lid top surface (8b), and four lid edge surfaces (8c) that are adjacent to one another in pairs. 24. High-temperature heat storage element (1) according to one of claims 20 through 23,characterized in thatthe outer shell components (3a;b;7;8) consist of a silicon carbide material, preferably a silicon carbide material with a ceramic, preferably silicate, bond or a nitride bond, or of silicon nitride or a material of the SiO2-Al2O3 series, in particular a mullite-containing material, or of MA spinel or a cordierite-containing material. 25. High-temperature heat storage element (1) according to one of the preceding claims,characterized in thatthe outer shell (3) does not contain a phase-change material. 26. High-temperature heat storage element (1) according to one of claims 20 through 25,characterized in thatthe outer shell components (3a;b;7;8) comprise an SiC content of 50 to 98 ma.%, more preferably 75 to 90 ma.%, and most preferably 80 to 85 ma.%, determined in accordance with DIN EN ISO 21068-2:2008-12. 27. High-temperature heat storage element (1) according to one of claims 20 through 26,characterized in thatthe outer shell components (3a;b;7;8) comprise a raw density according to DIN EN 993-1:2019-3 of 1.5 to 3.0 g / cm3, preferably 2.0 to 2.5 g / cm3, and more preferably 2.1 to 2.2 g / cm3. 28. High-temperature heat storage element (1) according to one of claims 20 through 27,characterized in thatthe outer shell components (3a;b;7;8) comprise a porosity according to DIN EN 993-1:2019-3 of 5 to 40 vol.-%, preferably 15 to 30 vol.-%, more preferably 20 to 25 vol.-%. 29. High-temperature heat storage element (1) according to one of claims 20 through 28,characterized in thatthe outer shell components (3a;b;7;8) comprise a cold compressive strength according to DIN EN 993-5:2019-3 of 30 to 150 MPa, preferably 50 to 100 MPa, determined on a test cylinder with a diameter of 36 mm and a height of 8 mm. 30. High-temperature heat storage element (1) according to one of claims 20 through 29,characterized in thatthe outer shell components (3a;b;7;8) comprise a thermal expansion at 1000 °C, in accordance with DIN EN ISO 1893-2008-9, of 0 to 2 %, preferably 0 to 1 %. 31. High-temperature heat storage element (1) according to one of claims 20 through 30,characterized in thatthe outer shell components (3a;b;7;8) comprise a thermal shock resistance of > 30 cycles, preferably > 70 cycles, determined in accordance with DIN 51068:2008-11 using water quenching. 32. High-temperature heat storage element (1) according to one of claims 20 through 31,characterized in thatthe outer shell components (3a;b;7;8) comprise a thermal conductivity of 10 to 20 W / mK, preferably 15 to 17 W / mK, at 800°C and / or of 8 to 18 W / mK, preferably 13 to 15 W / mK, at 1000°C and / or of 6 to 16 W / mK, preferably 11 to 13 W / mK, at 1200°C determined in accordance with DIN EN ISO 1893:2008-09. 33. High-temperature heat storage element (1) according to one of the preceding claims,characterized in thatthe high-temperature heat storage element (1) is cuboid in shape and comprises a longitudinal direction (1a), a width direction (1b) perpendicular thereto, and a height direction (1c) perpendicular to both the longitudinal direction (1a) and the width direction (1b), wherein the expansion joint (4) comprises a joint width of 0.1 to 5 %, preferably 0.5 to 2.0 %, of the dimension of the heat storage core 2 in the respective direction (1a;b;c). 34. High-temperature heat storage element (1) according to one of the preceding claims,characterized in thatthe expansion joint material (5) comprises at least one granular material made of refractory material, wherein the expansion joint material (5) preferably is a set, hardened refractory mortar or a loose fill. 35. A prefabricated high-temperature heat storage element component for forming a high-temperature heat storage element (1) according to one of claims 21 through 34,characterized in thatthe high-temperature heat storage element component comprises the heat storage core (2) and the crucible (7), and, between the heat storage core (2) and the crucible (7), the expansion joint material (5), wherein the heat storage core (2) and the crucible (7) are firmly connected to one another via the expansion joint material (5), and the crucible (7) is open at the top and uncovered. 36. High-temperature heat storage component (11), preferably high-temperature heat storage wall (12), for storing and recovering heat, preferably for a high-temperature heat storage, particularly for a high-temperature heat storage for storing and recovering heat from power generation or from furnace exhaust gases of industrial furnaces, comprising a plurality of high-temperature heat storage elements (1) arranged side-by-side and / or one above the other,characterized in thatthe high-temperature heat storage elements (1) are configured according to one of claims 1 through 34. 37. High-temperature heat storage component according to claim 36,characterized in thatat least partially, for high-temperature heat storage elements (1) arranged one above the other, the outer shell (3) of the lower high-temperature heat storage element (1) is formed by the crucible (7) of the lower high-temperature heat storage element (1) and the crucible bottom wall (10b) of the crucible (7) of the high-temperature heat storage element (1) arranged above it. 38. High-temperature heat storage for storing and recovering heat,characterized in thatthe high-temperature heat storage comprises at least one high-temperature heat storage element (1) according to one of claims 1 to 34 or a high-temperature heat storage component (11) according to 36 or 37. 39. Industrial furnace, preferably furnace used in the iron industry, the non-ferrous metal industry, firing furnace of the non-metallic industry, or furnace of a waste incineration plant,characterized in thatthe industrial furnace comprises a high-temperature heat storage according to claim 38 for storing and recovering heat from the furnace exhaust gases of the industrial furnace.