Heat storage

Abstract

High-temperature heat storage device with a storage container (1) for storing thermal energy, in particular for providing high-temperature heat for power generation and / or as process heat for industrial plants and processes, further in particular with a storage capacity of greater than 50 MWh, preferably greater than 100 MWh, and a heat resistance of the storage container (1) of 1000 °C to 1500 °C, wherein the storage container (1) has an upper container section (2) and a lower container section (3) connected to the upper container section (2), and the upper container section (2) forms an upper container closure, in particular a container dome (4), and the lower container section (3) forms a container bottom (6), wherein the upper container section (2) and the lower container section (3) delimit a charging chamber (7) for charging the storage container (1) with a heat-storing material (8),wherein, during a loading cycle, a charge containing the heat-storing material (8) introduced into the storage container (1) can be vertically flowed through by a hot carrier gas (9), in particular hot air, in order to charge the heat-storing material (8) by heat transfer from the hot carrier gas (9) to the heat-storing material (8), wherein, during a discharging cycle, the charge can be vertically flowed through by a colder carrier gas (10), in particular cold air, in order to discharge the heat-storing material (8) by heat transfer from the heat-storing material (8) to the colder carrier gas (10) and to heat the carrier gas (10), and wherein the heat-storing material (8) does not undergo any phase transformation during the loading cycle and the discharging cycle, characterized in that the carrier gas (9,10) can be fed to the feed chamber (7) via an annular channel (12) and / or discharged from the feed chamber (7) via the annular channel (12).

Description

[0001] The invention relates to a high-temperature heat storage device with a storage container for storing thermal energy, in particular for providing high-temperature heat for power generation and / or as process heat for industrial plants and processes, further in particular with a storage capacity of greater than 50 MWh, preferably greater than 100 MWh, and a heat resistance of the storage container of 1000 °C to 1500 °C, preferably of 1100 °C to 1300 °C, wherein the storage container has an upper container section and a lower container section connected to the upper container section, and the upper container section forms an upper container closure, in particular a container dome, and the lower container section forms a container base, wherein the upper container section and the lower container section delimit a charging space for charging the storage container with a heat-storing material,wherein, during a loading cycle, a charge of the heat-storing material introduced into the storage container can be vertically flowed through by a hot carrier gas, in particular hot air, when the storage container is positioned as intended, in order to charge the heat-storing material by heat transfer from the hot carrier gas to the heat-storing material; wherein, during a discharging cycle, the charge can be vertically flowed through by a colder carrier gas, in particular cold air, when the storage container is positioned as intended, in order to discharge the heat-storing material by heat transfer from the heat-storing material to the colder carrier gas and to heat the carrier gas; and wherein the heat-storing material does not undergo any phase transformation during the loading cycle or the discharging cycle.

[0002] The invention relates to so-called "sensible" heat storage devices, which change their "sensible" temperature during the charging and discharging process. Since this type of heat storage device does not undergo phase transitions, it can be used over a wide temperature range, particularly in the high-temperature range.

[0003] High-temperature heat storage systems can be used to store large amounts of thermal energy at temperatures above 1000°C. Waste heat in industrial or power plant processes is often not constant, but fluctuating. Energy-intensive industries in particular generate significant amounts of waste heat at high temperatures, which can be converted into process heat or electricity using thermal energy storage systems. The heat flow generated by the storage system can be used, for example, for targeted process recirculation or to generate electricity. When storing thermal energy from industrial processes, heat storage systems can improve efficiency and stabilize process conditions in high-temperature industrial processes. Such heat storage systems can also be used to provide industrial process heat from electricity.During periods of overproduction from renewable energies, electricity is converted into high-temperature heat. This heat is stored and later supplied to industrial consumers in the form of process heat. In combined cycle power plants, such heat storage systems can be used to decouple the provision of electricity and heat over time, with excess heat being temporarily stored in the heat storage system. To utilize the stored heat in a power plant process, heat from a hot carrier gas, in particular hot air, generated when a high-temperature storage system is discharged can be transferred to a working fluid of the power plant process, in particular to a working fluid of a steam power process. In a steam power process, the heat from the carrier gas can be used to generate steam, preheat feedwater, and / or superheat steam.In principle, however, it is also possible to supply the heat transferred to the carrier gas in the form of hot air to the combustion chamber of a conventional coal-fired power plant and / or a combined cycle power plant in order to burn a fuel such as coal or gas.

[0004] A thermoelectric storage power plant, for example, may comprise a compressor for compressing the carrier gas, at least one gas heater for heating the carrier gas, a plurality of high-temperature storage units for storing the heat of heated carrier gas, and at least one heat exchanger, such as a steam generator, for transferring the heat from heated carrier gas to a working fluid of a power plant process. If the carrier gas is heated in the gas heater by converting electrical energy into thermal energy, whereby the gas heater may have at least one electrical heating resistor for this purpose, electrical energy can be stored in the form of heat during periods of high power generation and low power demand during a loading cycle.During peak loads, at least one heat storage unit is discharged in at least one discharge cycle, and the resulting hot carrier gas is used to generate electricity, for example, to evaporate water for a steam power process. The generated electrical energy can then be fed back into the power grid. This allows for flexible, short-term, and cost-effective provision of electrical power during short-term high consumption peaks.

[0005] Electricity generation from renewable energy sources can experience fluctuations on various timescales, from seasonal fluctuations throughout the day to short-term fluctuations. Such fluctuations amplify fluctuations in electricity demand and increase the need for balancing options for peak loads. High-temperature thermal storage systems can convert excess solar or wind power into heat and temporarily store it in the thermal storage system. The stored thermal energy can then be reconverted to electricity when electricity demand increases accordingly.

[0006] The object of the present invention is to provide a high-temperature heat storage device for storing high-temperature heat, in particular for storing thermal surplus energy generated from the conversion of electrical surplus energy from conventional power generation or renewable power generation into heat and / or for storing thermal surplus energy from industrial or power plant processes and / or for a time-delayed provision of high-temperature heat for power generation and / or as process heat for industrial plants and processes as well as power plant plants, wherein the high-temperature heat storage device enables the storage of thermal energy at temperatures above 1000 °C, preferably at 1300 °C or more, and the provision of high-temperature heat in a process-technologically and structurally simple manner with low manufacturing, operating and maintenance costs of the heat storage device.

[0007] In particular, it is an object of the present invention to provide a high-temperature heat storage device which is characterized by a uniform flow around the heat-storing material in the storage container during loading and / or unloading at a low flow velocity and thus achieves an efficient thermal exchange between the carrier gas and the heat storage material.

[0008] Another object of the present invention is to provide a high-temperature heat storage device with improved mechanical and thermal strength.

[0009] Finally, the high-temperature heat storage device according to the invention should be characterized by a high degree of utilization, defined as the ratio of usable thermal energy to the energy used for charging the storage device, with energy losses being low due to improved storage device insulation.

[0010] Further advantageous features of the heat storage device according to the invention are intended to be high storage capacity, short charging and discharging times, and a high number of possible storage cycles, with storage capacity being defined as the maximum amount of heat that can be absorbed by the storage device. Factors influencing the storage capacity of thermal storage devices are the storage volume, the specific heat capacity of the storage medium, and the temperature difference. High storage capacity can only be achieved if homogeneous flow conditions exist within the storage device.

[0011] The temperature limit when loading the heat-storing material by contact with the hot carrier gas should be more than 1000 °C, up to 1500 °C, preferably between 1100 °C and 1300 °C.

[0012] The aforementioned objects are achieved by a high-temperature heat storage device having the features of claim 1. Advantageous embodiments of the invention are the subject of the subclaims.

[0013] According to the invention, to achieve the aforementioned objects, a supply and / or discharge of carrier gas into the storage container and / or from the storage container during the loading cycle and / or during the unloading cycle is provided via an annular channel. The annular channel enables a uniform distribution of the carrier gas and a uniform flow of a charge introduced into the charging chamber, in particular in the form of a bed made of a thermally conductive material with a low flow velocity, in order to ensure efficient thermal exchange between the carrier gas and the heat-storing material and to exclude as far as possible the formation of dead zones in the bed that are not involved in the heat transfer. Dead zones in the heat storage device, in which the heat storage material is not or not homogeneously flowed around by the carrier gas, lead to a reduction in the storage capacity, i.e.the maximum amount of heat that can be absorbed by or released from the storage system.

[0014] At the same time, a suitable design of the annular channel and the gas transition between the annular channel and the feed chamber allows the flow through the heat storage material to be achieved with a low pressure loss.

[0015] The invention relates to a sensible heat storage device, wherein the heat storage material does not change its physical state during loading or unloading, but rather heats up and cools down depending on whether the heat storage device is being loaded or unloaded. Sensible heat storage devices have the advantage of a simple design and are inexpensive to manufacture on an industrial scale, especially when the heat storage material is a cost-effective bulk material with a high heat capacity.

[0016] The annular channel has at least one channel opening for supplying carrier gas into the annular channel and / or for discharging carrier gas from the annular channel, and at least one gas passage for the transfer of the carrier gas between the annular channel and the charging chamber. The annular channel is preferably formed adjacent to the container bottom in the lower region of the storage container.

[0017] The storage container can have at least one container opening in the upper region adjacent to the upper container end for supplying carrier gas into the charging chamber or for discharging carrier gas from the charging chamber.

[0018] Preferably, hot carrier gas is fed into the annular channel in the area of ​​the storage vessel near the bottom, with the hot carrier gas flowing from the annular channel into the charging chamber via the gas passage. The hot carrier gas can then flow vertically upwards along the charging of the storage vessel with the heat-storing material and then exit the storage vessel via the vessel opening in the upper area of ​​the storage vessel. Heat transfer from the hot carrier gas results in the storage vessel being charged as the flow approaches the heat-storing material. When the storage vessel is discharged, colder carrier gas is then fed to the charging, particularly via the vessel opening in the upper area of ​​the storage vessel, with the colder carrier gas flowing downwards along the charging and being heated by heat transfer from the heat-storing material.The heated carrier gas can then flow from the feed chamber through the gas passage near the bottom of the storage vessel into the annular channel and is then discharged from the annular channel and thus from the storage vessel via the channel opening of the annular channel or another channel opening. However, a carrier gas flow from the bottom to the top of the storage vessel is not excluded.

[0019] Particularly preferably, the supply and discharge of the carrier gas during the loading cycle and during the unloading cycle takes place via only one channel opening in the annular channel and only one container opening in the storage container.

[0020] The heat storage device according to the invention is designed for vertical operation, so that the heat storage device is arranged vertically upright relative to the longitudinal axis of the storage container during the loading cycle and during the discharging cycle. The storage container is then flowed through in a vertical direction during both loading and discharging, ensuring heat transfer.

[0021] A particularly preferred structural design of the heat accumulator according to the invention provides that the lower container section is arranged concentrically to the upper container section, wherein the lower container section has a larger internal cross-sectional area than the upper container section and the upper container section partially dips into the lower container section on the bottom side.

[0022] The charging chamber can be formed by an upper charging zone and a lower charging zone. The upper charging zone can be delimited transversely to the installation direction of the storage container, in particular radially outwards, by the upper container section, and the lower charging zone can be delimited transversely to the installation direction of the storage container, in particular radially outwards, by the lower container section, wherein, preferably, the lower charging zone extends outwards transversely to the installation direction of the storage container, in particular in the radial direction, beyond the upper charging zone. The aforementioned embodiment of the invention enables a simple structural design of the storage container according to the invention and a homogeneous flow guidance of the carrier gas, in particular in conjunction with the annular channel according to the invention for supplying or discharging the carrier gas to or from the charging chamber.The lower feeding zone, which extends radially outward beyond the upper feeding zone, creates the possibility for a structurally simple design of the gas transition between the annular channel and the second feeding zone. The upper container section and the lower container section preferably have cylindrical container walls that delimit the feeding zones.

[0023] The annular channel is preferably arranged concentrically with the loading chamber, in particular concentrically with the upper container section. The annular channel particularly preferably extends circumferentially along the entire circumference of the upper container section. The annular channel is particularly preferably formed on the outer side of a side wall of the upper container section, wherein the side wall delimits the upper loading zone.

[0024] The energy storage device preferably has a cylindrical structure, with the upper container section and the lower container section each being cylindrical. The lower container section can then have a cylindrical side wall that concentrically surrounds a cylindrical side wall of the upper container section in the lower region near the edge of the upper container section. The annular channel can then be formed between the side walls of the two container sections.

[0025] The embodiments described below refer to the preferred cylindrical design of the storage container with container sections that have cylindrical container or side walls. It is understood that corresponding designs can also be provided and implemented for storage containers with a polygonal cross-sectional geometry, even if this is not expressly described below.

[0026] The annular channel can be formed between two concentric side walls of the upper container section and the lower container section, in particular wherein the annular channel is delimited by an outer surface of a side wall of the upper container section and an inner surface of a side wall of the lower container section arranged concentrically to the side wall of the upper container section, and / or wherein the annular channel is formed at the lower end of the upper container section, adjacent to the container bottom. When the heat storage unit is installed vertically on a base as intended, the annular channel is delimited by vertical wall sections of the container sections transversely to the longitudinal axis of the storage container or in the radial direction.

[0027] Preferably, the annular channel extends vertically to a lower edge of the side wall of the upper container section and is radially delimited outwardly by a vertical side wall of the lower container section. The annular channel can be terminated at the top by an inclined side wall of the lower container section, via which the upper container section and the lower container section are connected to one another. The annular channel can be closed at the sides and at the top, with the exception of the at least one channel opening provided for supplying and / or discharging carrier gas.

[0028] A suitable structural design of the storage tank, which is simple and cost-effective to manufacture and is characterized by a high mechanical strength of the construction, provides that at the bottom end of the upper tank section, a wall section of the upper tank section is designed as a hanging wall section.

[0029] By means of a hanging wall section at the lower end of the upper tank section, the lower area of ​​the charging space of the storage tank, which is delimited by the upper tank section, can be separated from the annular channel, at least in part.

[0030] Below the hanging wall section, however, the feeding chamber is open in the radial direction to the annular channel.

[0031] The hanging wall section preferably does not rest against the lower container section at the bottom. In the area below the connection point between the upper container section and the lower container section, the upper container section is then freely suspended and is preferably supported and stabilized at the connection point only via the connection to the lower container section. The annular space formed between the hanging wall of the upper container section and an outer wall of the lower container section can then form at least part of the annular channel.

[0032] Furthermore, the hanging wall section towards the feed chamber and the annular channel can be thermally insulated in order to ensure high temperature resistance of the storage tank in this area.

[0033] The upper and lower container sections may be metal components, with the upper and lower container sections each having a preferably outer metallic container wall, in particular made of steel. Fireproof insulation may be provided on the container wall, preferably radially inward, but optionally also radially outward.

[0034] The insulation of the container wall can be multi-layered. In particular, the insulation can be formed by an outer insulating layer facing the charging chamber made of a high-hardness insulating material, for example, in the form of a refractory brick lining, and an inner insulating layer of lower hardness arranged between the metallic container wall and the outer insulating layer, which can be formed, for example, by a cement-based insulating material.

[0035] The hanging wall section at the lower end of the upper tank section can have a cylindrical metal component as a support element, in particular a cylindrical steel component, which can have a fireproof insulation, in particular having a multi-layer structure, more particularly a two-layer structure, on the radially inner side, on the side facing the charging chamber, and preferably on the radially outer side, on the side facing the annular channel. The support element increases the rigidity of the upper tank section. This contributes to the high stability of the storage tank.

[0036] Preferably, the support element can be embedded on both sides in a thermal insulation layer made of a lower-hardness insulating material, for example, a cement-based insulating material. An outer insulation layer made of a higher-hardness insulating material, for example, in the form of a refractory brick lining, can be adjacent to the inner insulation layer thus formed. The outer insulation layer can then directly border the charging chamber (radially inward) and the annular channel (radially outward).

[0037] Particularly preferably, the support element of the hanging wall section can be connected, in particular welded, to a metallic side wall of the upper container section in the region of the connection point between the upper container section and the lower container section.

[0038] In order to ensure a high resistance of the construction, a cooling device can be provided for cooling the hanging wall section, in particular for cooling the support element. The cooling can be realized via cooling coils running concentrically around the support element, wherein, preferably, water cooling can be provided.

[0039] Alternatively, the upper container section can rest on the bottom of the lower container section.

[0040] A support structure can be provided, via which the upper container section is supported on the lower container section. Openings with a clear diameter several times the particle diameter can be provided in the area of ​​the support structure, allowing the heat-storing material to transfer from the feed chamber or feed zone into the annular channel. The support structure serves to absorb the weight of the upper container section and is subject to compression. Therefore, it is not necessary to integrate a metallic support into the support structure. Cooling of the support structure may then be unnecessary.

[0041] The support structure can comprise several, preferably annularly arranged, column-like structural sections, between which openings are formed for the transfer of the heat storage material from the charging chamber into the annular channel. Adjacent structural sections can converge at the top and be connected in an arched manner, with an opening below being bridged in the area of ​​the arched connection. An arched construction allows the support structure to achieve a high compressive load-bearing capacity.

[0042] The annular channel is preferably open toward the feed chamber, in particular toward the lower feed zone, with the opening forming the gas passage for carrier gas to the feed chamber, in particular with the annular channel being closed in the radial direction toward the upper feed zone. The annular channel is also preferably closed at the top, with the exception of the at least one channel opening for the supply and / or discharge of carrier gas.

[0043] The annular channel extends vertically downwards, preferably to the lower edge of the section of the upper container section designed as a hanging wall. A gas passage plane placed at the lower outer edge of the section of the upper container section designed as a hanging wall can functionally and structurally delimit the annular channel downwards.

[0044] The container bottom of the storage container can be formed by a bottom wall of the lower container section, which delimits the feed space downwards in the vertical direction and extends in the radial direction preferably to below the gas passage of the annular channel.

[0045] A central discharge opening for heat storage material can be provided in the bottom wall.

[0046] On the inside, the lower container section can have a conical sliding surface for the heat-storing material, which extends below the annular channel, preferably from the discharge opening in the bottom wall to the radially outer edge of the annular channel. The desired position of a bed of heat-storing material in the lower charging zone can shift outwards with increasing operation of the storage container, whereby the angle of repose, i.e. the angle between the inclined outer surface of the bed and a horizontal reference plane, decreases with increasing operation of the heat storage device and the bed in the area below the annular channel migrates towards the gas passage of the annular channel. Finally, the bed boundary of the heat-storage material can shift so far towards the annular channel that the bed passes through the gas passage of the annular channel and engages in the annular channel. The bed boundary orthe outer surface of the bed can then run at least partially within the annular channel and above a gas passage plane of the annular channel placed at the lower edge of the upper container section.

[0047] To promote a homogeneous flow through the annular channel and a uniform flow of the heat-storing material in the feed chamber, it is preferable not to provide any retaining elements, such as heat-resistant perforated plates or perforated bricks, in the area of ​​the gas passage from the annular channel to the feed chamber. The heat-storing material is then not retained in the feed chamber and can, as described above, "migrate" toward the annular channel with the operation of the heat storage device and eventually even "rise" or penetrate the annular channel.

[0048] The gas passage of the annular channel to the feed chamber can preferably extend substantially annularly over the entire circumferential length of the annular channel. In other words, the annular channel is preferably open all the way around the feed chamber. The annular channel can have a constant opening width (clear width) of the gas passage in the circumferential direction of the annular channel. This leads to low flow losses and a uniform flow to the heat-storing material when the carrier gas is supplied or discharged via the annular channel.

[0049] Preferably, the annular channel has a constant clear width in the vertical direction, starting from the gas passage upwards to an inclined side wall of the lower container section.

[0050] Particularly preferably, the charging chamber is provided with a lumpy and / or spherical heat-storage material; in particular, thermal storage spheres made of aluminum oxide ceramic (AL2O3 ceramic) can be provided as the heat-storage material. The average material and / or sphere diameter can be between 1.0 cm and 10.0 cm, more preferably greater than or equal to 1.5 cm and / or up to 3 cm.

[0051] The density of the heat-storing material is preferably in the range between 3000 kg / m 3 and 6000 kg / m 3 , preferably between 3000 kg / m 3 and 4000 kg / m 3 and further preferably at approx. 3500 kg / m 3 This is especially true for the use of spherical heat storage material made of aluminum oxide ceramic. Such heat storage spheres are characterized by low material costs, high heat capacity and conductivity, and high heat resistance.

[0052] The opening area of ​​the gas passage may correspond to a multiple of the grain size, in particular the sphere diameter, of the heat-storing material used, so that the heat-storing material can pass through the gas passage of the annular channel during the operational displacement of the bed in the radial direction towards the annular channel.

[0053] Preferably, the storage tank is operated as a fixed bed storage below the fluidization limit of the bed.

[0054] Particularly preferably, the heat-storing material flows through the gas passage of the annular channel at a carrier gas velocity below the minimum fluidization velocity, in particular, the carrier gas velocity being less than 80%, preferably less than 50%, and more preferably less than 25%, of the minimum fluidization velocity. This reliably prevents fluidization of the bed when the heat-storing material flows through the annular channel.

[0055] The minimum fluidization velocity, the lower limit for the existence of a fluidized bed, can be calculated, for example, using the Ergun equation, which shows a small deviation between measured and calculated values. The calculation of the minimum fluidization velocity is derived, for example, from the publication Werther J.: Strömungsmechanische Grundlagen der Wirbelschicht, Chem.-Ing.-Tech. 49, No. 3, pages 193 to 202, (1977). The minimum fluidization velocity is also calculated for the maximum loading temperature of the storage vessel and the absolute pressure at which loading / discharging occurs.

[0056] Particularly preferably, the gas velocity of the carrier gas when flowing through the annular channel, in particular during the discharge cycle of the heat storage device, is less than or equal to the gas velocity of the carrier gas when flowing through the upper container section of the storage container, in particular during the loading cycle. The volume flow of the carrier gas is preferably selected such that the gas velocity of the carrier gas when flowing through the annular channel and the gas velocity of the carrier gas when flowing through the upper container section are each less than the minimum fluidization velocity. This improves the heat transfer between the heat-storing material and the carrier gas, and the discharge of portions of the heat-storing material due to fluidization of the bed is reliably excluded, even in the annular channel.

[0057] In this context, it is further preferably provided in a heat storage device according to the invention that the clear inner cross-sectional area of ​​the annular channel, in particular in the region of the gas passage at the level of the gas passage plane, is greater than or equal to the clear inner cross-sectional area of ​​the upper container section at the upper end of the charging chamber. The inner (clear) cross-sectional area of ​​the upper container section can be between 3 m 2 and 100 m 2 , preferably between 30 m 2 and 80 m 2 , amount to.

[0058] The specific mass flow of the carrier gas flowing through the heat storage material in the storage vessel can be in the range between 0.5 and 6.0 kg / (s*m 2 ), based on the inner cross-sectional area of ​​the upper section of the storage tank in the area where the heat-storing material is loaded.

[0059] The grain size, preferably the mean diameter, of the heat-storing material can be in the range between 10 mm and 40 mm, for example in the range of 15 mm.

[0060] The density of the heat-storing material can preferably be in the range between 3000 kg / m 3 and 6000 kg / m 3 , further preferably in the range of approx. 3500 kg / m 3 lay.

[0061] Under minimum fluidization conditions, the porosity of the feed can reach values ​​between 0.25 and 0.6, in particular 0.4.

[0062] The carrier gas is preferably supplied to the storage vessel at an overpressure level, wherein the storage vessel is designed as a pressure vessel and wherein the pressure vessel is designed for a permissible operating pressure of more than 1.5 bar (absolute), in particular of more than 5 bar (absolute), more particularly of more than 8 bar (absolute), preferably of 9 bar (absolute), and, more preferably, for a maximum operating pressure of less than 20 bar (absolute).

[0063] Furthermore, during loading of the storage vessel, a supply of hot carrier gas to the annular channel is provided at a temperature of more than 1000 °C to 1500 °C, preferably between 1100 °C and 1300 °C. This requires appropriate heat resistance of the heat storage device according to the invention, in particular the storage vessel and all gas lines provided for the gas supply and gas discharge of hot carrier gas.

[0064] In the area of ​​the container dome, the maximum temperature during operation of the heat storage unit can be between 20 °C and 1500 °C, for example, approximately 500 °C. Due to the supply of hot carrier gas, the temperatures in the area of ​​the annular channel can be between 1000 °C and 1500 °C, preferably 1100 °C and 1300 °C. The desired discharge temperature required for heat utilization can be at least 500 °C, preferably at least 600 °C, and up to 1500 °C, more preferably up to 800 °C. The above-specified minimum and maximum temperature values ​​refer in particular to the interconnection of several storage units.

[0065] A preferred structural design of the storage container provides that the supply of hot carrier gas into the annular channel takes place in the upper region of the annular channel, in particular directed obliquely to the upper container section.

[0066] The storage tank is preferably designed as a steel structure with tank walls made of or containing a steel material and has fire-resistant insulation at least in some areas, in particular multi-layered and / or on both sides, particularly in the area adjacent to the annular channel. Furthermore, insulation is provided on a suspended tank wall at the bottom end of the upper tank section. The steel material can be of the same grade or a comparable grade.

[0067] For thermal insulation, insulation can be provided on a side of the upper container section and / or the lower container section facing the charging chamber and / or the annular channel, which insulation has a multi-layer structure, in particular a two-layer structure, with at least one fire-resistant outer insulating layer made of an insulating material with a high hardness, facing the charging chamber, in particular the first, upper charging zone, and with at least one further inner insulating layer with a lower hardness, adjacent to the outer insulating layer.

[0068] If the storage tank has an upper tank section configured as a hanging wall at its lower end, the hanging wall can be insulated on both sides, on the side facing the feed zone and the side facing the annular channel. Additionally, cooling of the hanging wall can be provided, preferably by means of cooling lines, cooling coils, or the like, which can be embedded in the insulating layer of lower hardness, preferably on the side of the hanging wall facing the annular channel.

[0069] The outer insulation layer can be made of a highly hard insulating material, for example, in the form of a lining made of refractory bricks, for example, a phosphate-bonded brick (80% alumina, fired). A cement-based insulating material can be used to form the inner insulation layer. The outer insulation layer with greater hardness achieves high compressive strength against the fill. The inner insulation layer with lower hardness, on the other hand, primarily serves to increase thermal stability.

[0070] Furthermore, to ensure uniform flow through the bulk column in the feed chamber, the height-to-diameter ratio in the upper feed zone, which is radially bounded by a preferably cylindrical vessel wall of the upper vessel section, can be between 0.5 and 1.8, preferably between 1.0 and 1.6. The height-to-diameter ratio represents the ratio of the active bulk height to the inner diameter of the upper vessel section bounding the upper feed zone.

[0071] Further features, advantages and possible applications of the present invention will become apparent from the following description of exemplary embodiments with reference to the drawings and the drawings themselves. All described and / or illustrated features, individually or in any combination, form the subject matter of the present invention, regardless of their summary in the claims or their reference back to them.

[0072] The drawing shows: Fig. 1 is a schematic longitudinal sectional view of a storage container for a high-temperature heat storage device according to the invention; Fig. 2 a schematic longitudinal sectional view of a further embodiment of a storage container for a high-temperature heat storage device according to the invention with, in comparison to Fig. 1 higher level of detail and Fig. 3 a schematic longitudinal sectional view of a further embodiment of a storage container for a high-temperature heat storage device according to the invention.

[0073] In the Fig. 1 and Fig. 2 schematically shows possible embodiments of storage containers 1 of a high-temperature heat storage device for storing thermal energy, in particular wherein the high-temperature heat storage device is designed and suitable for providing high-temperature heat for power generation and / or as process heat for industrial plants and processes or for power plants, further in particular wherein the storage container has a storage capacity of greater than 100 MWh and is designed for feed temperatures of greater than 1000 °C to 1500 °C, preferably from 1100 °C to 1300 °C.

[0074] In the Fig. 1 and Fig. 2 Components provided with identical reference numerals have the same or similar structural design and / or functionality, even if this is not expressly described in detail.

[0075] The storage tank 1 has an upper tank section 2 and a lower tank section 3. The upper tank section 2 forms an upper tank closure, in particular a tank dome 4 with an upper side wall 5 in the shape of a spherical segment. The lower tank section 3 forms a tank bottom 6 of the storage tank 1.

[0076] The upper container section 2 and the lower container section 3 delimit a charging chamber 7 for charging with a heat-storing material 8. The heat-storing material 8 is shown only schematically and, in the present case, consists, for example, of aluminum oxide-containing ceramic spheres with a diameter of, for example, 1.5 cm to 2 cm. The heat-storing material 8 is introduced into the charging chamber 7 in the form of a bed. The terms "charging" and "bed" are used alternatively and synonymously below. In principle, however, the storage container 1 could also be charged or filled with a lumpy, non-spherical heat-storing material. Alternatively, the heat storage container 1 could also have any desired heat-storing elements inserted into the storage container 1.

[0077] The storage container 1 is designed for vertical installation on a base and is arranged vertically upright during a loading cycle and during a discharging cycle. A carrier gas 9, 10 flows through the storage container 1 essentially vertically during loading and discharging, particularly through the upper container section 2.

[0078] During the loading cycle, hot carrier gas 9, in particular hot air at a temperature of, for example, 1200°C, is supplied to the charging chamber 7. At least one electric air heater (not shown) can be provided to generate the hot air. The hot carrier gas 9 flows through the charging chamber 7 and thus the bed of heat-storing material 8 in a vertically ascending direction in order to heat the heat-storing material 8 by heat transfer from the hot carrier gas 9. In principle, the hot carrier gas 9 could also flow through the storage container 1 in a vertically downward direction.

[0079] During the discharge cycle, a colder carrier gas 10, in particular cold air, flows vertically from top to bottom through the charging chamber 7 and thus the bed of heat-storing material 8 in order to heat the colder carrier gas 10 by heat transfer from the heat-storing material 8. In principle, the carrier gas 10 could also be guided from bottom to top through the storage container 1 during discharge.

[0080] The supply of hot carrier gas 9 into the storage container 1 during the loading cycle and the removal of carrier gas 10 heated in the storage container 1 from the storage container 1 during the discharge cycle takes place via at least one channel opening 11 of an annular channel 12.

[0081] At least one container opening 13 is provided in the region of the container dome 4 to discharge the carrier gas 9 from the storage container 1 during the loading cycle after flowing through the storage container 1. The colder carrier gas 10 is supplied to the storage container 1 during unloading via the container opening 13 in the region of the container dome 4.

[0082] Furthermore, the storage container 1 has an upper filling opening 14 for filling the heat-storing material 8 into the interior of the storage container 1 and a discharge opening 15 centrally in the region of the container bottom 6 in order to be able to discharge the heat-storing material 8 from the storage container 1 as required.

[0083] The annular channel 12 is bounded radially inwardly by a vertical side wall 16 of the upper container section 2 and radially outwardly by a vertical side wall 17 of the lower container section 3. The side walls 16, 17 preferably form outer walls of the storage container. The side walls 16, 17 can, as in Fig. 2 with a higher level of detail, have an internal multi-layer insulation, which in Fig. 1 is not shown.

[0084] The side walls 16, 17 are preferably made of a metallic material, in particular steel. The connection between the upper container section 3 and the lower container section 2 is preferably achieved by welding in the connection area of ​​the side walls 16, 17.

[0085] The side walls 16, 17 are cylindrical at least in sections, wherein the side wall 17 is arranged at least in sections concentrically to the side wall 16 and wherein the cylindrical part of the lower container section 3 has a larger inner diameter than the cylindrical part of the upper container section 2. The upper container section 2 dips with its bottom end partially into the lower container section 3.

[0086] An upper loading zone 18 of the loading chamber 7 is radially delimited by the cylindrical side wall 16 of the upper container section 2. A further, lower loading zone 19 is radially delimited by the cylindrical side wall 17 of the lower container section 3. The loading zones 18, 19 merge into one another and form a continuous loading chamber 7. The lower loading zone 19 extends radially beyond the upper loading zone 18 to the side wall 17 of the lower container section 3.

[0087] The annular channel 12 is arranged concentrically to the side wall 16 of the upper container section 2. The annular channel 12 is open at the bottom, or bottom side, so that a vertically downwardly open glass passage 20 is realized at the level of a horizontal passage plane 21. The passage plane 21 delimits the annular channel 12 in the vertical downward direction and runs through the lower outer edge 38 of the vertical side wall 16 of the upper container section 2. The hot carrier gas 9 enters the second feed zone 19 from the annular channel 12 via the gas passage 20, and the heated carrier gas 10 exits the second feed zone 19 into the annular channel 12.

[0088] In the vertical upward direction, the annular channel 12 is closed with the exception of at least one channel opening 11. At the top, the annular channel 12 is closed by an inclined side wall 22, which connects the vertical side wall 16 of the upper container section 2 and the vertical side wall 17 of the lower container section 3. In the embodiment shown, the side wall 16 of the upper container section 2 is formed at the bottom end as a hanging wall section 23. The annular space between the hanging wall section 23 and an upper region of the cylindrical side wall 17 of the lower container section 3 then forms the annular channel 12, or delimits it in the radial direction. The gas passage plane 21 lies at the level of the lower outer edge 38 of the hanging wall section 23 of the side wall 16 of the upper container section 2.

[0089] The gas passage 20 preferably extends at least substantially annularly over the entire circumferential length of the annular channel 12 and has, with respect to the gas passage plane 21, an equal width of the annular surface, which is delimited in the radial direction by the side walls 16, 17 of the container sections 2, 3.

[0090] The container bottom 6 has a spherical segment-shaped bottom wall 24, which supports a multi-layer insulation 25 on the inside, formed from insulating bricks 26 and refractory bricks 27. The fill of heat-storing material 8 rests on the insulation 25.

[0091] The inner surface 28 of the container base 6 is conical. The inner surface 28 extends radially to below the gas passage 20 or to the inner surface of the cylindrical side wall 17 of the lower container section 3. Preferably, the inner surface 28 of the container base 6 rises continuously in the radial direction from the central discharge opening 15 in the container base 6 to the side wall 17 of the lower container section 3. This forms a sliding surface for the heat-storing material 8, which extends radially outward from the container center and reaches below the gas passage 20 of the annular channel 12.

[0092] After filling the storage tank 1 with the heat-storing material 8, the position of the fill boundary 29a-29d of the fill surface 30 of the heat-storing material 8 and the fill angle change during storage operation. The fill boundary 29a-29d defines the position of an outer fill surface 30 of the heat-storing material 8 in the lower feed zone 19 adjacent to the annular channel 12. This is shown schematically in Fig. 2 shown.

[0093] Preferably, in the region of the gas passage 20 of the annular channel 12 to the feed chamber 7, no retaining elements are provided for retaining the heat-storing material 8 in the feed chamber 7, so that the heat-storing material 8 is displaced in the direction of the annular channel 12 with increasing operation and can also rise in the annular channel 12.

[0094] Starting from an initial fill boundary 29a with a large angle of repose or steep fill surface 30, the fill boundary 29b-d of the heat-storing material 8 is increasingly shifted radially outwards and upwards during storage operation, so that a fill boundary 29d with a small angle of repose or flat fill surface 30 can be reached, in which the fill surface 30 lies at least partially, preferably over its entire surface, within the annular channel 12 and the annular channel 12 is delimited downwards by the fill surface 30 in the vertical direction over its entire clear width.

[0095] To ensure high heat transfer between the carrier gas 9, 10, good gas separation from the heat-storing material 8, particularly when using ceramic, more particularly spherical, heat-storing materials 8, and to ensure that the heat-storing material 8 is not discharged from the storage container 1 during loading and / or unloading of the storage container 1, the flow through the bed of heat-storing material 8 is provided at a carrier gas velocity that is significantly below the minimum fluidization velocity. In particular, the carrier gas velocity is less than 80%, preferably less than 50%, more preferably less than 25%, of the minimum fluidization velocity.

[0096] Based in particular on the bed porosity of a bed of the heat-storing material 8 under minimum fluidization conditions, the viscosity and density of the carrier gas 9, 10, the average grain or sphere diameter of the heat-storing material 8 and its density, as well as the gas pressure of the carrier gas 9, 10, the minimum fluidization velocity of the carrier gas 9, 10 can be determined, for example using the Ergun equation known to the person skilled in the art, at which fluidization of the bed does not yet occur when the carrier gas 9, 10 flows through the bed of the heat-storing material 8.

[0097] In particular, a flow through the heat-storing material 8 is provided in the region of the gas passage 20 of the annular channel 12, particularly preferably at the level of the gas passage plane 21, with a carrier gas velocity below the minimum fluidization velocity.

[0098] In this context, a structural design of the storage container 1 is preferably provided such that the inner (clear) cross-sectional area 31 of the upper container section 16 and the inner (clear) cross-sectional area 32 of the annular channel 12, in particular at the level of the gas passage plane 21, are preferably at least substantially the same size or wherein the inner (clear) cross-sectional area 32 of the annular channel 12 is larger than the inner (clear) cross-sectional area 31 of the upper container section 16.With the same volume flow of the carrier gas 9, 10, fluidization of the bed of heat-storing material 8 can be equally reliably prevented when loading the heat-storing material 8 by supplying hot carrier gas 9 into the storage container 1 and when discharging the heat-storing material 8 by supplying colder carrier gas 10 into the storage container 1, wherein the carrier gas 9, 10 flows through the bed both in the region of the upper container section 2 with the inner cross-sectional area 31 and in the region of the gas passage 20 of the annular channel 12 with the inner cross-sectional area 32, in each case with a sufficiently low gas velocity below the minimum fluidization velocity.

[0099] The storage tank 1 is designed as a pressure tank, in particular for an operating pressure of, for example, more than 8 bar (absolute), further in particular of, for example, 9 bar (absolute) or more.

[0100] The specific mass flow of the carrier gas can be between 0.5 and 6.0 kg / (s*m 2 ), based on the inner cross-sectional area 31 of the storage tank 1 ( Fig. 1).

[0101] The operating pressure of the storage tank 1 can be between 6 bar (absolute), in particular 8 bar (absolute) and 10 bar (absolute).

[0102] The annular channel 12 can have a heat resistance of more than 1000 °C to 1500 °C, for example preferably 1200 °C. At this temperature level, the hot carrier gas 9 can be fed to the storage vessel 1 via the channel opening 11. The carrier gas 9 cooled during loading can be discharged from the storage vessel 1 via the vessel opening 13 in the region of the vessel dome 4 at a temperature level between 500 °C and 1500 °C, for example at approximately 850 °C (single vessel operation) or even at 1200 °C (when several storage vessels are connected together). It is understood that a corresponding heat resistance is also required for the Fig. 1 and Fig. 2 not shown supply and discharge lines of the carrier gas 9, 10 to or from the storage container 1 can be provided.

[0103] The carrier gas heating to the loading temperature of the storage tank 1 can preferably be carried out by means of electrical gas heaters of the high-temperature heat storage unit (not shown).

[0104] The conduit opening 11 for supplying hot carrier gas 9 to the annular channel 12 is preferably arranged opposite the hanging wall section 23 of the side wall 16 of the upper container section 2. The gas supply is thus directed toward the hanging wall section 23. At the hanging wall section 23, the carrier gas flow is redirected toward the gas passage 20.

[0105] The inner cross-sectional area 31, which is limited by the side wall 16 of the upper container section 2, can be in a range between 3 m 2 and 100 m 2 , especially between 30 m 2 and 80 m 2 , lay.

[0106] To ensure a uniform flow through the bulk column in the feed chamber 7, the height-to-diameter ratio can be between 0.5 and 1.8, preferably between 1.0 and 1.6. The height-to-diameter ratio ( Fig. 2) is related to the active filling height 33 in the upper container section 2 and the inner diameter 34 of the container section 2 predetermined by the cylindrical side wall 16 of the upper container section.

[0107] As in Fig. As shown in detail in Figure 2, the bottom wall 24, which is made of a steel material, has thermal insulation 25 on its inside. The insulation 25 is formed by an outer layer 27 facing the charging chamber 7, for example, made of refractory bricks, and an adjacent inner layer 26, for example, made of insulating bricks. This achieves a high compressive strength in the area of ​​the tank bottom 6, since the storage tank 1 is subject to high static and dynamic compressive loads in this area due to the fill of heat-storing material 8 resting on the tank bottom 6.

[0108] The lower wall section 23 of the upper tank section 2, designed as a hanging wall, is also subject to high mechanical stress due to the fill material lying against it on the sides. In addition, the wall section 23 borders the annular channel 12 and is exposed to high thermal stress, particularly when the storage tank 1 is being loaded. To ensure sufficient thermal insulation and high compressive strength, the hanging wall section 23 has, on its side facing the charging chamber 7 and on the side of the annular channel 12, a refractory outer layer 36 made of an insulating material with high hardness and an inner layer 37 with lower hardness, radially adjacent to the outer layer 36. The outer layer 36 can be formed by refractory bricks, while the inner layer 37 can be formed by insulating concrete.

[0109] Furthermore, the lower wall section 23, designed as a hanging wall, has a metallic support element 45, which can in particular be a cylindrical steel component. The support element 45 is preferably welded to the side wall 16 of the upper container section 2 in the region of the connection point between the upper container section 2 and the lower container section 3.

[0110] Furthermore, a Fig. 2, a cooling device 39, shown only schematically, is provided to cool the support element 45 provided in the wall section 23 designed as a hanging wall. The cooling device 39 has a supply line 40 and a discharge line 41 for cooling water, which is guided through a cooling coil running around the wall section 23. The cooling coil is embedded in the inner layer 37 of the insulation.

[0111] The inclined wall 22 and the side wall 17 of the lower container section 3, which delimit the annular channel 12 upwards and radially outwards, also have a multi-layer insulation applied to the inside of the container walls 17, 22. Again, an outer layer 36 of higher hardness directed toward the annular channel 12, for example, formed by refractory bricks, and an inner layer 37 of lower hardness directed toward the outer container walls 17, 22, for example, formed by insulating concrete, can be provided.

[0112] In addition, to increase pressure stability, the annular channel 12 has rounded inner edges in the connection area of ​​the inclined wall 22 of the lower container section 3 to the side wall 16 of the upper container section 2.

[0113] On the side of a line section 35 of the annular channel 12 which opens into the channel opening 11, the annular channel 12 is also equipped with a previously described two-layer insulation which is formed by an outer layer 36 of higher hardness directed towards the annular channel 12 and an inner layer 37 of lower hardness.

[0114] The container dome 4 of the upper container section 2 has an outer layer 42 made of a material with a higher hardness and directed towards the charging chamber 7, and an inner layer 43 made of an insulating material with a lower hardness and radially adjoining it, as well as an outer container wall 44, wherein a sprayed insulating layer made of refractory bricks can be provided as the outer layer 42 and a layer of sprayed insulating concrete can be provided as the inner layer 43.

[0115] Fig. 3 shows schematically an alternative embodiment of the Fig. 2 shown storage tank 1. The same reference numerals indicate functionally and / or structurally identical features of the storage tank 1.

[0116] Deviating from the Fig. The storage container 1 shown in Figure 2 is Fig. 3, it is provided that the upper container section 2 rests on the bottom side on the lower container section 3 or is supported on the lower container section 3 via a support structure 46 not shown in detail.

[0117] The support structure 46 can be a masonry made of temperature-resistant bricks. In particular, the support structure 46 does not have any metallic support elements. The weight of the upper container section 2 is transferred to the lower container section 3 via the support structure 46. Cooling of the support structure 46 is not required if it does not have any metallic support elements.

[0118] In Fig. 2 shows, merely by way of example, an embodiment in which the supporting structure 46 has a radially inner and a radially outer insulating layer 36 made of a temperature-resistant material, in particular of temperature-resistant bricks. A cement-based inner layer 37 made of an insulating material of lower hardness can be provided in the area between the outer layer 36.

[0119] It is not shown that the upper container section 2 can also have a different construction of the support structure 46 at its lower bottom end, wherein the support structure 46 can, for example, be formed entirely from fire-resistant brickwork.

[0120] Further in Fig. 2 schematically shows that the support structure 46 can have annularly arranged column-like structural sections 47 which converge upwards in an arc shape, so that in particular a vault-like support structure 46 is formed in regions.

[0121] Openings 48 are provided between adjacent structural sections 47 to allow the heat storage material 8 to pass from the charging chamber 7 or the charging zone 19 into the annular channel 12. For this purpose, the opening width of the openings 48 is a multiple of the particle size of the heat storage material 8, ensuring a free passage of the heat storage material 8 through the openings 48.

[0122] It is understood that the supporting structure 46 may also be one of the Fig. 3 may have a different geometric configuration and / or a different structure. For example, longitudinal or transverse slots may be provided that penetrate a substantially annular, flat support structure 46 to allow the heat storage material 8 to pass over. List of reference symbols: 1 storage tank 2 container section 3 Container section 4 container dome 5 Side wall 6 Container bottom 7 Loading room 8 Heat storage material 9 Carrier gas 10 Carrier gas 11 Channel opening 12 ring canal 13 Container opening 14 Filling opening 15 Discharge opening 16 Side wall 17 Side wall 18 Feeding zone 19 Feeding zone 20 Gas passage 21 Gas passage level 22 side wall 23 wall section 24 floor wall 25 Insulation 26 inner layer 27 Outer layer 28 inner surface 29 discharge limit 30 filling area 31 cross-sectional area 32 cross-sectional area 33 dumping height 34 inner diameter 35 line section 36 Outer layer 37 inner layer 38 outer edge 39 Cooling device 40 supply line 41 Derivation 42 Outer layer 43 inner layer 44 Container wall 45 Support element 46 Supporting structure 47 Structural section 48 Opening QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited non-patent literature

[0000] Werther J.: Fluid mechanics fundamentals of the fluidized bed, Chem.-Ing.-Tech. 49, No. 3, pages 193 to 202, (1977

[0055]

Claims

[1] High-temperature heat storage device with a storage container (1) for storing thermal energy, in particular for providing high-temperature heat for power generation and / or as process heat for industrial plants and processes, further in particular with a storage capacity of greater than 50 MWh, preferably greater than 100 MWh, and a heat resistance of the storage container (1) of 1000 °C to 1500 °C, wherein the storage container (1) has an upper container section (2) and a lower container section (3) connected to the upper container section (2), and the upper container section (2) forms an upper container closure, in particular a container dome (4), and the lower container section (3) forms a container bottom (6), wherein the upper container section (2) and the lower container section (3) delimit a charging space (7) for charging the storage container (1) with a heat-storing material (8),wherein, during a loading cycle, a charge containing the heat-storing material (8) introduced into the storage container (1) can be vertically flowed through by a hot carrier gas (9), in particular hot air, in order to charge the heat-storing material (8) by heat transfer from the hot carrier gas (9) to the heat-storing material (8), wherein, during a discharging cycle, the charge can be vertically flowed through by a colder carrier gas (10), in particular cold air, in order to discharge the heat-storing material (8) by heat transfer from the heat-storing material (8) to the colder carrier gas (10) and to heat the carrier gas (10), and wherein the heat-storing material (8) does not undergo any phase transformation during the loading cycle and the discharging cycle, characterized bythat the carrier gas (9, 10) can be fed to the feed chamber (7) via an annular channel (12) and / or discharged from the feed chamber (7) via the annular channel (12). [2] Heat storage device according to claim 1, characterized by that the lower container section (3) is arranged concentrically to the upper container section (2), wherein the lower container section (3) has a larger internal cross-sectional area than the upper container section (2) and the upper container section (2) partially dips into the lower container section (3) on the bottom side. [3] Heat storage device according to claim 1 or 2, characterized byin that the loading space (7) is formed by an upper loading zone (18) and a lower loading zone (19), wherein the upper loading zone (18) is delimited transversely to the longitudinal direction of the storage container (1), in particular radially outwards, by the upper container section (2) and the lower loading zone (19) is delimited transversely to the longitudinal direction of the storage container (1), in particular radially outwards, by the lower container section (3), wherein, preferably, the lower loading zone (19) extends transversely to the erection direction of the storage container (1), in particular in the radial direction, outwards beyond the upper loading zone (18). [4] Heat storage device according to one of the preceding claims, characterized bythat the annular channel (12) is arranged concentrically to the loading space (7), in particular concentrically to the upper container section (2), wherein, preferably, the annular channel (12) extends over the entire circumferential length of a side wall (16) of the upper container section (2). [5] Heat storage device according to one of the preceding claims, characterized by that the upper container section (2) is designed as a hanging wall section (23) at the bottom end, in particular wherein the hanging wall section (23) has a wall cooling system, and / or that the upper container section (2) is supported on the lower container section (3) via a support structure (46). [6] Heat storage device according to one of the preceding claims, characterized byin that the annular channel (12) is designed to be open to the loading chamber (7), in particular to the lower loading zone (19), wherein the opening forms a gas passage (20) for carrier gas (9, 10) to the loading chamber (7), in particular wherein the annular channel (12) is designed to be closed laterally to the upper loading zone (18). [7] Heat storage device according to one of the preceding claims, characterized by that the annular channel (12) in the region of the gas passage (20) to the charging chamber (7) is free of retaining elements designed to retain the heat-storing material (6) in the charging chamber (7). [8] Heat accumulator according to one of the preceding claims, characterized by that the inner cross-sectional area (32) of the annular channel in the region of the gas passage plane (21) of the gas passage (2) is greater than or equal to the inner cross-sectional area (31) of the upper container section (2).

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