Recovery of energy

Abstract

The invention relates to a device (110) comprising a plurality of tubes. At least one of the tubes is designed as a reaction tube (112) for at least one feed material to flow therethrough. The device (110) has at least one energy recovery enclosure (130) which at least partially encloses the reaction tube (112). The energy recovery enclosure (130) has at least one thermoelectric generator which is configured to convert heat into electrical energy.

Description

[0001] Energy recovery

[0002] The invention relates to a device comprising a plurality of hollow cylindrical tubes, a system and a method for recovering electrical energy.

[0003] The device can be part of a plant, for example, a plant for carrying out at least one endothermic reaction, a heating plant, a preheating plant, a steam cracker, a steam reformer, an alkane dehydrogenation plant, a reformer, a dry reforming plant, a styrene production plant, an ethylbenzene dehydrogenation plant, a cracker, a catalytic cracker, acetylene production plant, and a dehydrogenation plant. The device can be used in particular for heating feedstock to a temperature in the range from 200°C to 1700°C, preferably from 300°C to 1400°C, particularly preferably from 400°C to 875°C. However, other fields of application are also conceivable.

[0004] Production plants such as steam crackers are generally familiar to those skilled in the art; see, for example, Ethylene; Heinz Zimmermann, Roland Walzl; Ullmann's Encyclopedia of Industrial Chemistry (15 April 2009). In steam crackers, for example, crude petroleum (naphtha) is split into ethylene and propylene at high temperatures in the presence of steam. In a so-called convection zone of the steam cracker, the crude petroleum is preheated and hot steam is added. In a subsequent radiation zone, the crude petroleum is split, or cracked, into ethylene and propylene at around 850 °C. Conventional natural gas is burned to heat the steam cracker, which is associated with carbon emissions. In conventional steam crackers, the heat generated during natural gas combustion is not only used for cracking, but the waste heat rising in the chimney is also used to preheat the crude petroleum in the convection zone.Such so-called conventional production plants are known, for example, from EP 2 653 524 A1, US 4,361 ,478 A, EP 0245 839 A1 or EP3415587A1.

[0005] Electrically heatable reactors are also known, for example from WO 2015 / 197181 A1, WO 2020 / 035575 A1, and WO 2020 / 035574 A1, the contents of which are hereby incorporated by reference. Electrically heatable reactors can enable CO2-neutral operation of the reactor. Heat integration for an electrically heatable reactor is known from PCT / EP2021 / 077144, filed on October 1, 2021, the contents of which are hereby incorporated by reference.

[0006] US 3,881,962 A describes a thermoelectric-type generator which isolates the fuel combustion zone from a series of thermoelectric elements or modules and utilizes two-phase vapor heat transfer, in which transfer from a liquid phase to a gaseous phase occurs through the intervening presence of a boiler housing a fuel burner. The fuel consumed in the boiler generates heat, which impinges on a jacket of the boiler in which a vaporizable fluid is enclosed. The heated vapor thus produced flows through a series of heat exchange loops radiating from the boiler to heat the hot junctions of the thermoelectric elements. Electrical energy is generated by a potential developed between the hot and cold junctions of said elements.

[0007] JP H06 154589 A describes an insulated container equipped with: a device that heats or cools the main body of the container; a device that supplies a heat exchange fluid into the container to control the temperature in the container and to conduct heat exchange between the heat exchange fluid and the atmosphere in the container; a thermoelectric device that converts the thermal energy obtained by heat exchange with the heat exchange fluid discharged from the container after the heat exchange into electrical energy; a device that stores the electrical energy generated by the device.

[0008] Energy is required to operate conventional and electrically heated reactors. Energy recovery remains a problem.

[0009] It is therefore an object of the present invention to provide a device, a system, and a method for recovering electrical energy that at least largely avoid the disadvantages of known devices and methods. In particular, energy recovery should be enabled.

[0010] This object is achieved by a device, a system, and a method having the features of the independent claims. Preferred embodiments of the invention are specified, among other things, in the associated subclaims and their interrelations.

[0011] In the following, the terms "have", "have", "comprise" or "include" or any grammatical variations thereof are used in a non-exclusive manner. Accordingly, these terms can refer both to situations in which, apart from the feature introduced by these terms, no further features are present, or to situations in which one or more further features are present. For example, the expression "A has B", "A has B", "A comprises B" or "A includes B" can refer both to the situation in which, apart from B, no further element is present in A (i.e., a situation in which A consists exclusively of B), and to the situation in which, in addition to B, one or more further elements are present in A, for example element e, elements C and D, or even further elements.

[0012] Furthermore, it should be noted that the terms "at least one" and "one or more," as well as grammatical variations of these terms or similar terms, when used in connection with one or more elements or features and intended to express that the element or feature may be provided once or multiple times, are generally used only once, for example when the feature or element is first introduced. When the feature or element is subsequently mentioned again, the corresponding term "at least one" or "one or more" is generally no longer used, without limiting the possibility that the feature or element may be provided once or multiple times.

[0013] Furthermore, the terms “preferably”, “in particular”, “for example” or similar terms are used hereinafter in connection with optional features, without limiting alternative embodiments. Thus, features introduced by these terms are optional features, and these features are not intended to limit the scope of the claims, and in particular the independent claims. Thus, as those skilled in the art will recognize, the invention can also be carried out using other embodiments. Similarly, features introduced by “in one embodiment of the invention” or by “in an embodiment of the invention” are understood as optional features, without limiting alternative embodiments or the scope of the independent claims.Furthermore, these introductory expressions are intended to leave untouched all possibilities of combining the features introduced thereby with other features, whether optional or non-optional.

[0014] In a first aspect of the present invention, a device comprising a plurality of tubes is proposed. At least one of the tubes is configured as a reaction tube for the flow of at least one feedstock. The device has at least one energy recovery enclosure that at least partially encloses the reaction tube. The energy recovery enclosure has at least one thermoelectric generator configured to convert heat into electrical energy.

[0015] The device can be used, and the process described below can be applied, in a plant selected from the group consisting of: a plant for carrying out at least one endothermic reaction, a plant for heating, a plant for preheating, a steam cracker, a steam reformer, a plant for alkane dehydrogenation, a reformer, a plant for dry reforming, a plant for styrene production, a plant for ethylbenzene dehydrogenation, production of acetylene, a cracker, a catalytic cracker, a plant for dehydrogenation.

[0016] The term "pipe," as used herein, is a broad term to which its usual and common meaning should be attributed, as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. The term can refer, without limitation, in particular to a hollow body of any shape. A length of the pipe can be greater than its diameter. The pipe can have an interior space separated from an external environment by a lateral surface. The pipe can be configured as a flow-through pipe, also referred to as a flow-through pipe. The pipe can comprise at least one pipeline and / or at least one pipeline segment and / or at least one pipeline coil. A pipeline segment can be a subsection of a pipeline. The terms "pipe," "pipe," "pipe segment," and "pipe coil" are used synonymously below.

[0017] For example, the tube may be a hollow cylindrical tube. The term "hollow cylindrical tube" as used herein is a broad term to which its usual and common meaning should be given, as understood by those skilled in the art. The term is not limited to a specific or adapted meaning. The term may, without limitation, refer in particular to a tube having an at least partially cylindrical section. The tube may be completely cylindrical or may also have non-cylindrical sections. The hollow cylindrical tube may, for example, be a circular cylinder with a radius r and a length h, also referred to as the height. The circular cylinder may have a bore along an axis. Deviations from a circular cylindrical geometry are also conceivable. For example, the tube may have an elliptical cross-sectional area. For example, the tube may have a prismatic geometry.For example, at least one of the tubes of the device may have a rectangular geometry.

[0018] The device comprises a plurality of tubes. The reaction tube can be surrounded by additional tubes. The tubes can be arranged concentrically. The reaction tube can be arranged as a central tube surrounded by the additional tubes. The device can be designed in multiple parts, for example, with an M-, U-, or W-shaped coil as the reaction tube and the additional tubes attached to straight sections of equal length.

[0019] The term "feedstock" as used herein is a broad term to which its usual and common meaning should be given, as understood by one skilled in the art. The term is not limited to a specific or adapted meaning. The term can, without limitation, refer in particular to any flowable medium. The feedstock can be liquid or gaseous. The feedstock can comprise at least one medium selected from the group consisting of: air, at least one oxygen-containing medium, water, water vapor, and at least one oxidizing medium. Other feedstocks are also conceivable.

[0020] In the plants listed above for conducting at least one endothermic reaction, a number of side reactions occur that can, for example, lead to coking of plant components, particularly the reaction tubes. It is therefore common practice, for example, to conduct exothermic reactions at fixed or regular intervals to burn off the coking, particularly a so-called decoking of the plant. During decoking, the feedstock, also known as decoking gas, can be fed into the reaction tube, and the coking from at least one exothermic reaction is burned off.

[0021] The term "flowing" as used herein is a broad term which should be given its ordinary and common meaning as understood by one of ordinary skill in the art. The term is not limited to any specific or adapted meaning. The term may refer, without limitation, to one or more of receiving the feedstock in the reaction tube, flowing the feedstock through the reaction tube, passing the feedstock, or transporting the feedstock, for example, from a first end of the reaction tube to a second end of the reaction tube.

[0022] The term "reaction tube" as used herein is a broad term to which its ordinary and common meaning should be given, as understood by one skilled in the art. The term is not limited to any specific or adapted meaning. The term may, without limitation, refer in particular to a tube configured for the flow of the feedstock. The reaction tube may be configured so that at least one chemical reaction and / or a partial reaction can take place in the reaction tube. In particular, the reaction tube is configured for the flow of at least one feedstock to carry out at least one endothermic reaction. For example, at least one endothermic reaction may take place in the reaction tube. For example, an exothermic reaction for decoking and / or oxidizing the deposits formed during the endothermic reaction may be carried out in the reaction tube.

[0023] The reaction tube can, for example, be configured to heat the feedstock. The reaction tube can be a reactor and / or a furnace, or a part of these. For example, the reaction tube can be designed as a reactor of a combustion furnace and / or an electrically heatable reactor. For example, the reaction tube can be configured as described, for example, in H. Zimmermann and R. Walzl, "Ethylene," Ullmann's Encyclopedia of Industrial Chemistry, 2012. Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, DOI:

[0024] 10.1002 / 14356007.a10_045.pub3, EP 2 653 524 A1, US 4,361,478 A, EP 0245 839 A1, or EP3415587A1. For example, the reaction tube can be designed as an electrically heatable reactor, as described, for example, in WO 2015 / 197181 A1, WO 2020 / 035575 A1, and WO 2020 / 035574 A1.

[0025] The geometry and / or surfaces and / or material of the reaction tube can depend on the feedstock. Alternatively or additionally, the geometry and / or surfaces and / or material of the reaction tube can depend on a desired reaction and / or the avoidance of a specific reaction and / or the optimization of the reaction and / or other factors. For example, the reaction tube can be designed as a hollow cylinder.

[0026] The device can have a plurality of reaction tubes. The device can have I reaction tubes, where I is a natural number greater than or equal to two. For example, the device can have at least two, three, four, five, or even more reaction tubes. The device can have up to one hundred reaction tubes, for example. The reaction tubes can be identical or different. The reaction tubes can, for example, be different in terms of diameter, and / or length, and / or geometry. The reaction tubes can have symmetrical and / or asymmetrical tubes and / or combinations thereof. In a purely symmetrical design, the device can have reaction tubes of an identical tube type."Asymmetrical tubes" and "combinations of symmetrical and asymmetrical tubes" can be understood to mean that the device can comprise any combination of tube types, which can, for example, be connected in parallel or in series as desired. The term "tube type" as used herein is a broad term to which its usual and common meaning should be given, as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. The term can, without limitation, refer in particular to a category or type of tube characterized by certain features.The pipe type can be characterized by at least one feature selected from the group consisting of: a horizontal configuration of the pipe; a vertical configuration of the pipe; a length at the inlet (11) and / or outlet (12) and / or transition (13); a diameter at the inlet (d1) and outlet (d2) and / or transition (d3); number n of passes; length per pass; diameter per pass; geometry; surface; and material. The device can have a combination of at least two different pipe types that are connected in parallel and / or in series. For example, the device can have pipes of different lengths at the inlet (11) and / or outlet (12) and / or transition (13). For example, the device can have pipes with an asymmetry of the diameters at the inlet (d1) and / or outlet (d2) and / or transition (d3). For example, the device can have pipes with a different number of passes.For example, the device can have tubes with passes of different lengths per pass and / or different diameters per pass. In principle, any combination of all tube types in parallel and / or in series is conceivable. The device can have a plurality of inlets and / or outlets and / or production streams. The reaction tubes of different or identical tube types can be arranged in parallel and / or in series with multiple inlets and / or outlets. Possible tubes for reaction tubes can be available in various tube types in the form of a modular system and can be selected and combined as desired depending on the intended use. Using tubes of different tube types can enable more precise temperature control and / or adaptation of the reaction in the event of fluctuating feed and / or a selective reaction yield and / or optimized process technology.The tubes may have identical or different geometries and / or surfaces and / or materials.

[0027] The reaction tubes can be interconnected and thus form a pipe system. The term "pipe system," as used here, is a broad term to which its usual and common meaning should be given, as understood by those skilled in the art. The term is not limited to a specific or adapted meaning. The term can, without limitation, refer in particular to a device comprising at least two, in particular interconnected, pipes. The pipe system can have supply and discharge pipes. The pipe system can have at least one inlet for receiving the feedstock. The pipe system can have at least one outlet for discharging the feedstock. "Interconnected" can be understood to mean that the pipes are in fluid communication with one another. Thus, the pipes can be arranged and connected in such a way that the feedstock flows through the pipes sequentially.Several or all of the pipes can be configured in series and / or in parallel. The pipes can be connected in parallel such that the feedstock can flow through at least two pipes in parallel. The pipes, in particular the pipes connected in parallel, can be configured to transport different feedstocks in parallel. In particular, for transporting different feedstocks, the pipes connected in parallel can have different geometries and / or surfaces and / or materials. In particular, for transporting one feedstock, several or all of the pipes can be configured in parallel such that the feedstock can be distributed between the pipes configured in parallel. Combinations of a serial and parallel connection are also conceivable.

[0028] The reaction tube can be an electrically conductive, in particular metallic, or an electrically non-conductive reaction tube.

[0029] For example, the reaction tube may be an electrically conductive reaction tube. The term "electrically conductive" as used herein is a broad term to which its ordinary and customary meaning should be given, as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. The term may, without limitation, refer in particular to a material of the reaction tube that is configured to conduct electrical current. The reaction tube may have a specific electrical resistance of less than 10 1 Q m. The reaction tube can have a specific electrical resistance p of 1 »10 -8 Q m < p < 10 -1Q m. In the context of the present invention, the specific electrical resistance refers to the specific electrical resistance at room temperature. For example, the reaction tube can comprise at least one material selected from the group consisting of: at least one ferritic material, at least one austenitic material, at least one metal, at least one metallic alloy, copper, aluminum, iron, steel, Cr, and / or Ni alloys, graphite, carbon, carbide, and silicide.

[0030] The reaction tubes and the corresponding supply and discharge pipes can be connected to one another in a fluid-conducting manner. If electrically conductive pipes are used as the reaction tubes, the supply and discharge pipes can be galvanically separated from one another. “Galvanically separated from one another” can be understood to mean that the pipes and the supply and discharge pipes are separated from one another in such a way that no electrical conduction and / or tolerable electrical conduction occurs between the pipes and the supply and discharge pipes. The device can have at least one insulator, in particular a plurality of insulators. The galvanic isolation between the respective pipes and the supply and discharge pipes can be ensured by the insulators. The insulators can ensure a free flow of the feedstock.

[0031] However, designs of the reaction tube as electrically non-conductive tubes or poorly conductive tubes are also conceivable. For example, the reaction tube can be made of a ceramic or materials with a similar specific resistance. The reaction tube can be designed as a galvanic insulator. The reaction tube can have a specific electrical resistance of more than 10 5 Qm. The reaction tube can have a specific electrical resistance p of 1x10 5 Q m < p < 1x10 20 m, preferably from 1x10 5 Q m < p < 1x10 14 m. For example, the reaction tube can be designed as a ceramic tube. For example, the reaction tube can comprise at least one material selected from the group consisting of: MgO, Al2O3, B nitride, Al nitride, Al silicate (mullite), ZrO2, Mg-Al silicate (cordierite), Mg silicate (steatite), Si nitride.

[0032] The term "envelope" as used herein is a broad term to which its ordinary and common meaning should be given as understood by one skilled in the art. The term is not limited to any specific or adapted meaning. The term may, without limitation, refer in particular to an element or a plurality of elements that form a planar and complete or partial boundary between an inner and an outer region. The enclosure may be a sheath. The enclosure may be one or more of a tube, a thin film, a coating, or a layer that at least partially surrounds and / or encloses another element of the device. The terms "surround" and "enclose" are used synonymously herein. The enclosure may perform various functions, such as heating, cooling, conducting current, galvanically insulating, or others.

[0033] For example, the device may comprise at least one heating jacket. The device may comprise at least one current or voltage source configured to generate an electric current in the heating jacket, which heats the reaction tube through Joule heating generated when the electric current passes through the heating jacket. The term "heating jacket" as used herein is a broad term to which its usual and common meaning should be given, as understood by those skilled in the art. The term is not limited to a specific or adapted meaning. The term may, without limitation, refer in particular to a jacket configured to transfer energy supplied to it in the form of heat to the reaction tube. The heating jacket may at least partially surround the reaction tube. The geometry and / or material of the heating jacket may be adapted to the reaction tube to be heated.This makes it possible to heat the reaction tube in an energy-efficient manner.

[0034] The heating jacket can comprise at least one material selected from the group consisting of ferritic or austenitic materials, e.g., CrNi alloy, CrMo, or ceramic. For example, the heating jacket can be made of at least one metal and / or at least one alloy, such as copper, aluminum, iron, steel or Cr or Ni alloys, graphite, carbon, carbides, or silicides. Semiconductors are also conceivable as materials for the heating jacket, for example, Ge, Si, selenides, tellurides, arsenides, and antimonide.

[0035] The heating jacket may be a conductive heating jacket. The term "conductive heating jacket," as used here, is a broad term to which its usual and common meaning should be attributed, as understood by a person skilled in the art. The term is not limited to the suitability of the heating jacket, in particular at least one material of the heating jacket, which is designed to conduct an electrical current. The heating jacket, in particular with a connected current or voltage source, may have a specific electrical resistance p of 1x10 -8 Q m < p < 10 5m. The heating jacket can have a thermal conductivity A of 10 W / (mK) < A < 6000 W / (mK), preferably 20 W / (mK) < A < 5000 W / (mK). In the context of the present invention, the thermal conductivity refers to thermal conductivity at room temperature. The heating jacket can be temperature-resistant in a range up to 2000°C, preferably up to 1300°C, particularly preferably up to 1000°C. The term "temperature-resistant" as used here is a broad term to which its usual and common meaning should be given, as understood by a person skilled in the art. The term is not limited to a specific or adapted meaning. The term can, without limitation, refer in particular to a resistance of the heating jacket, in particular of a material of the heating jacket, to temperatures, in particular high temperatures.

[0036] As stated above, the device can comprise at least one current or at least one voltage source configured to generate an electric current in the heating jacket, which heats the reaction tube through Joule heat generated when the electric current passes through the heating jacket. The current and / or voltage source can comprise a single-phase or multi-phase alternating current and / or single-phase or multi-phase alternating voltage source, or a direct current and / or direct voltage source. The device can comprise at least one supply and discharge line electrically connecting the current and / or voltage source to the heating jacket.

[0037] The device may, for example, comprise at least one alternating current and / or at least one alternating voltage source. The alternating current and / or alternating voltage source may be single-phase or multi-phase. The term "alternating current source," as used herein, is a broad term to which its ordinary and common meaning should be given, as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. The term may, without limitation, refer in particular to a power source configured to provide an alternating current. The term "alternating current," as used herein, is a broad term to which its ordinary and common meaning should be given, as understood by those skilled in the art. The term is not limited to any specific or adapted meaning.The term can, without limitation, refer in particular to an electric current whose polarity changes in a regular time-based repetition. For example, the alternating current can be a sinusoidal alternating current. The term “single-phase,” as used herein, is a broad term which should be given its ordinary and common meaning as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. The term can, without limitation, refer in particular to an alternating current source which provides an electric current with a single phase. The term “multi-phase,” as used herein, is a broad term which should be given its ordinary and common meaning as understood by those skilled in the art. The term is not limited to any specific or adapted meaning.The term can, without limitation, refer in particular to an alternating current source that provides an electric current with more than one phase. The term “AC voltage source,” as used herein, is a broad term that should be given its ordinary and common meaning as understood by those skilled in the art. The term is not limited to a specific or adapted meaning. The term can, without limitation, refer in particular to a voltage source that is configured to provide an alternating voltage. The term “AC voltage,” as used herein, is a broad term that should be given its ordinary and common meaning as understood by those skilled in the art. The term is not limited to a specific or adapted meaning. The term can, without limitation, refer in particular to a voltage whose magnitude and polarity repeats regularly over time.For example, the alternating voltage can be a sinusoidal alternating voltage. The voltage generated by the alternating voltage source causes a current to flow, in particular, an alternating current to flow. A "single-phase" alternating voltage source can be understood as an alternating voltage source that provides the alternating current with a single phase. A "multi-phase" alternating voltage source can be understood as an alternating voltage source that provides the alternating current with more than one phase.

[0038] The device may comprise at least one direct current and / or at least one direct voltage source. The term “direct current source,” as used herein, is a broad term which should be given its ordinary and common meaning as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. The term may, without limitation, refer in particular to a device which is configured to provide a direct current. The term “direct voltage source,” as used herein, is a broad term which should be given its ordinary and common meaning as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. The term may, without limitation, refer in particular to a device which is configured to provide a direct voltage.The direct current source and / or the direct voltage source can be configured to generate a direct current in the heating enclosure. The term “direct current,” as used herein, is a broad term to which its ordinary and common meaning should be given, as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. The term can refer, without limitation, in particular, to an electrical current that is substantially constant in magnitude and direction. The term “direct voltage,” as used herein, is a broad term to which its ordinary and common meaning should be given, as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. The term can refer, without limitation, in particular, to an electrical voltage that is substantially constant."Substantially constant" can be understood as a current or voltage whose fluctuations are insignificant for the intended effect. The device can have a plurality of heating zones. For example, the device can have two or more heating zones. Each heating zone can comprise at least one heating enclosure. The device can also have regions in which no heating of the feedstock occurs, for example, pure transport zones.

[0039] The device can have a plurality of current and / or voltage sources, wherein the current and / or voltage sources are selected from the group consisting of: single-phase or multi-phase AC and / or single-phase or multi-phase AC voltage sources or DC and / or DC voltage sources, and a combination thereof. The device can have 2 to M different current and / or voltage sources, where M is a natural number greater than or equal to three. The current and / or voltage sources can be designed with or without the possibility of controlling at least one electrical output variable. The current and / or voltage sources can be electrically controllable independently of one another. The current and / or voltage sources can be designed identically or differently.For example, the device can be configured such that current and / or voltage can be adjusted for different zones, in particular heating zones of the device, in particular the heating jacket. The device can have a plurality of reaction tubes. Reaction tubes can share a common heating jacket or each have an assigned heating jacket. The reaction tubes can belong to different temperature ranges or zones. The reaction tubes themselves can also have temperature zones. One or more current or voltage sources can be assigned to the individual reaction tubes. The current and / or voltage supply can be adjusted, for example by using at least one regulator, depending on the reaction and process technology. By using a plurality of current and / or voltage sources, the voltage in particular can be varied for different zones.This ensures that the current does not become too high, which would result in reaction tubes that are too hot or, conversely, in reaction tubes that are too cold.

[0040] The device can have a plurality of single-phase or multi-phase alternating current or alternating voltage sources. Each reaction tube can be assigned at least one heating jacket with at least one alternating current and / or alternating voltage source, which is connected to the heating jacket, in particular electrically via at least one electrical connection. Furthermore, embodiments are conceivable in which at least two reaction tubes share a heating jacket and an alternating current and / or alternating voltage source. To connect the alternating current or alternating voltage source and the heating jacket, the device can have 2 to N supply and discharge lines, where N is a natural number greater than or equal to three. The respective alternating current and / or alternating voltage source can be configured to generate an electric current in the respective heating jacket.The alternating current and / or alternating voltage sources can be either regulated or unregulated. The alternating current and / or alternating voltage sources can be designed with or without the possibility of regulating at least one electrical output variable. The term "output variable" as used here is a broad term to which its usual and common meaning should be given, as understood by a person skilled in the art. The term is not limited to a specific or adapted meaning. The term can, without limitation, refer in particular to a current and / or voltage value and / or a current and / or voltage signal. The device can have 2 to M different alternating current and / or alternating voltage sources, where M is a natural number greater than or equal to three. The alternating current and / or alternating voltage sources can be electrically controllable independently of one another.For example, a different current can be generated in each heating jacket and different temperatures can be achieved in the reaction tubes.

[0041] The device can have a plurality of direct current and / or direct voltage sources. Each reaction tube can be assigned at least one heating jacket and at least one direct current and / or direct voltage source, which is connected to the heating jacket, in particular electrically via at least one electrical connection. Furthermore, embodiments are conceivable in which at least two reaction tubes share a heating jacket and a direct current and / or direct voltage source. To connect the direct current and / or direct voltage sources and the heating cylinder, the device can have 2 to N positive poles and / or conductors and 2 to N negative poles and / or conductors, where N is a natural number greater than or equal to three. The respective direct current and / or direct voltage source can be configured to generate an electric current in the respective heating jacket.The generated current can heat the respective reaction tube through Joule heat, which is generated when the electric current passes through the heating jacket, to heat the feedstock.

[0042] The current generated in the heating jacket can heat the respective reaction tube through Joule heating, which is created when the electric current passes through the heating jacket, to heat the feedstock. The term "heating the reaction tube," as used herein, is a broad term to which its usual and common meaning should be given, as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. The term can, without limitation, refer in particular to a process that results in a change in the temperature of the reaction tube, in particular an increase in the temperature of the reaction tube, and / or in the temperature of the reaction tube remaining substantially constant, for example, when the reaction taking place in the reaction tube absorbs as much heat as it receives. The terms "heating" and "warming" are used synonymously.The feedstock can, for example, be heated to a predefined or predetermined temperature value. The device can be configured to heat the feedstock to a temperature in the range from 200°C to 1700°C, preferably 300°C to 1400°C, particularly preferably 400°C to 875°C. However, other temperatures and temperature ranges are also conceivable. The reaction tube can be configured to at least partially absorb the Joule heat generated by the heating jacket and at least partially transfer it to the feedstock. For example, at least one endothermic reaction can take place in the reaction tube. The term “endothermic reaction” as used here is a broad term to which its usual and common meaning should be given, as understood by a person skilled in the art. The term is not limited to any specific or adapted meaning.The term can, without limitation, refer in particular to a reaction in which energy, particularly in the form of heat, is absorbed from the environment. The endothermic reaction can involve heating and / or preheating the feedstock. In particular, the feedstock can be heated in the reaction tube.

[0043] The device can have at least one temperature sensor configured to determine, in particular measure, a temperature of the reaction tube. The temperature sensor can comprise an electrical or electronic element configured to generate an electrical signal as a function of the temperature. For example, the temperature sensor can have at least one element selected from the group consisting of: a thermistor, a PTC thermistor, a semiconductor temperature sensor, a temperature sensor with a quartz crystal, a thermocouple, a pyroelectric material, a pyrometer, a thermal imaging camera, a ferromagnetic temperature sensor, and a fiber optic temperature sensor. The temperature can be measured at the inlet and outlet of the reaction tube, in and / or on the reaction tube.For example, measurements can be taken at multiple points in the reaction tube to determine the temperature along the length of the reaction tube and adjust it for optimal process control. Temperature control can be achieved using at least one control element. This can, for example, switch off the power or voltage supply in the event of a so-called hotspot. If the temperature is too low, the control element can increase the power or voltage supply. The temperature sensor can be connected to the control system via a wireless link or a fixed connection. The control system can be connected to the power or voltage source via a wireless link or a fixed connection. Temperature measurement and control can be possible in so-called "closed-loop mode" using built-in temperature sensors and current and / or voltage control.

[0044] The device may have at least one control unit configured to regulate the current or voltage source depending on a temperature measured by the temperature sensor. The term "control unit," as used herein, is a broad term to which its usual and common meaning should be given, as understood by a person skilled in the art. The term is not limited to a specific or adapted meaning. The term may, without limitation, refer in particular to an electronic device configured to control and / or regulate at least one element of the device. For example, the control unit may be configured to evaluate signals generated by the temperature sensor and to regulate the current or voltage source depending on the measured temperature.For example, one or more electronic connections can be provided between the temperature sensor and the control unit for this purpose. The control unit can, for example, comprise at least one data processing device, for example at least one computer or microcontroller. The data processing device can have one or more volatile and / or non-volatile data memories, wherein the data processing device can, for example, be programmatically configured to control the temperature sensor. The control unit can further comprise at least one interface, for example an electronic interface and / or a human-machine interface such as an input / output device such as a display and / or a keyboard. The control unit can, for example, be centrally or decentrally constructed. Other configurations are also conceivable.The control unit can have at least one A / D converter. The device can include an online temperature measurement. Within the context of the present invention, an "online temperature measurement" can be understood as a temperature measurement with at least one temperature sensor, which takes place during the transport and / or reaction of the feedstock in the reaction tube. This allows the temperature to be controlled during operation. In particular, temperature measurement and control can take place over the entire length of the reactor.

[0045] The heating jacket can be arranged such that the heating jacket at least partially surrounds the reaction tube. “At least partially surrounded” can be understood to mean embodiments in which one element completely surrounds another, and embodiments in which only partial areas of the other element are surrounded by the element. For example, this can be understood to mean embodiments in which the heating jacket completely surrounds the reaction tube, and embodiments in which only partial areas of the reaction tube are surrounded by the heating jacket. For example, the reaction tube can be arranged as an inner cylinder in the heating jacket. For example, a plurality of reaction tubes can be arranged within the heating jacket. For example, several heating jackets can be arranged in a clamp-like manner around the reaction tubes.For example, the reaction tube can be spiral-shaped, and the heating jacket can be arranged around the reaction tube. Embodiments are also conceivable in which different or similar heating jackets are arranged around different regions of a reaction tube or several reaction tubes, enabling individual heating of the regions of the reaction tube or reaction tubes.

[0046] The heating jacket can directly surround the reaction tube and be configured to transfer its heat generated by electricity to the reaction tube. The term "directly surrounded," as used herein, is a broad term to which its usual and common meaning should be given, as understood by those skilled in the art. The term is not limited to a specific or adapted meaning. The term can, without limitation, refer in particular to an arrangement of the reaction tube and the heating jacket as adjacent tubes of the device. In particular, no further tube can be arranged between the reaction tube and the heating jacket. The reaction tube, for example, can be an electrically non-conductive, in particular non-metallic, reaction tube. The reaction tube can be configured as a directly electrically heated reaction tube.The reaction tube and the heating jacket can be designed as a monolithic tube, in particular as a single electrically conductive tube, which is heated by Joule heating through the flow of electric current. The reaction tube and the heating jacket can be made of one piece.

[0047] However, other arrangements of reaction tube and heating jacket are also conceivable. For example, the heating jacket can indirectly surround the reaction tube. The term "indirectly surrounded" as used here is a broad term to which its usual and common meaning should be given, as understood by a person skilled in the art. The term is not limited to a specific or adapted meaning. The term can, without limitation, refer in particular to an arrangement of the reaction tube and the heating jacket in which at least one further element of the device, in particular a further tube, is arranged between the reaction tube and the heating jacket. The reaction tube, for example, can be an electrically conductive, in particular metallic, reaction tube. The device can have at least one, in particular heat-conducting, galvanic insulator.The galvanic insulator can be arranged between the reaction tube and the heating jacket. The galvanic insulator can be configured to galvanically insulate the reaction tube from the heating jacket and to transfer heat from the heating jacket to the reaction tube. The term "galvanic insulator," as used herein, is a broad term to which its ordinary and common meaning should be given, as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. The term can, without limitation, refer in particular to a non-conductor or poor conductor. The galvanic insulator can have a specific electrical resistivity p of 1x10 5 Q m < p < 1x10 14m. A heat transfer coefficient can be high. The galvanic insulator can have a thermal conductivity A of 10 W / (mK) < A < 6000 W / (mK), preferably 20 W / (mK) < A < 5000 W / (mK). The galvanic insulator can comprise at least one material selected from the group consisting of ceramic, glass-like, glass-fiber-reinforced, plastic-like or resin-like materials, such as ceramic, steatite, porcelain, glass, glass-fiber-reinforced plastic, epoxy resin, thermoset, elastomers, as well as electrically sufficiently insulating liquids, an insulating paint. The galvanic insulator can be designed as one or more of a tube, a thin film, a coating, or a layer. The galvanic insulator can, for example, be a flexible galvanic insulator, for example a thin film. This allows expansion in the event of temperature differences.The galvanic insulator can be configured to transfer heat from the live heating jacket to the reaction tube. The galvanic insulator can galvanically insulate the reaction tube from the heating jacket.

[0048] The device has at least one energy recovery enclosure that at least partially encloses the reaction tube. “At least partially enclosing” can be understood to mean embodiments in which one element completely encloses another element, and embodiments in which only partial areas of the other element are enclosed by the element. For example, embodiments can be understood in which the energy recovery enclosure completely encloses the reaction tube, and embodiments in which only partial areas of the reaction tube are enclosed by the energy recovery enclosure. The term “energy recovery enclosure,” as used herein, is a broad term to which its usual and common meaning should be given, as understood by those skilled in the art. The term is not limited to any specific or adapted meaning.The term may, without limitation, refer in particular to an enclosure designed to recover at least part of the energy used to heat the feedstock.

[0049] The energy recovery enclosure includes at least one thermoelectric generator (TEG) configured to convert heat into electrical energy. The term "convert," as used herein, is a broad term that should be given its ordinary and customary meaning as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. The term may refer, without limitation, in particular to thermoelectric energy conversion. The conversion of heat into energy may be at least partial. For example, the TEG may have an efficiency of 5-10%.

[0050] The term "thermoelectric generator," also referred to as a Seebeck generator as used herein, is a broad term to which its ordinary and common meaning should be given, as understood by one skilled in the art. The term is not limited to any specific or adapted meaning. The term can refer, without limitation, in particular to a device configured to convert heat flows (temperature differences) into electrical energy by means of the so-called Seebeck effect. The energy recovery enclosure can be configured to convert heat generated in the reaction tube during an exothermic reaction, particularly during decoking, into electrical energy. A chemical reaction can be considered exothermic if it releases more energy than was initially supplied to it as activation energy. The exothermic reaction can occur during decoking and / or oxidation of the deposits in the reaction tube.For example, a temperature difference can be caused by a temperature of 1000 °C in the reaction tube and a temperature of 20 °C on an outer casing of the device, for example after cooling.

[0051] The TEG can be designed, for example, as described in US 2014 / 0238459 A1, Mengjun Zhang et al., “Performance comparison of annular and flat-plate thermoelectric generators for cylindrical hot source“, https: / / doi.Org / 10.1016 / j.egyr.2021.01.008, 2352-4847 / 2021 published by Elsevier Ltd. The use of TEGs is known in other technical fields, for example, for thermal power plants from KR 20190040433, for thermoelectric gas stoves for domestic use from CN 106953548, for vehicle exhaust systems from EP3151293, or for resistance heaters from JP2008032341 and JP2002171776.

[0052] The energy recovery enclosure may comprise at least one material having a thermoelectric quality value ZT of > 0.5, preferably > 0.8, particularly preferably > 1. The thermoelectric quality value can be described as ZT=(a 2 (T) •O(T)»T) / K(T), where a is the Seebeck coefficient, a is the electrical conductivity, K is the specific thermal conductivity of the material. The energy recovery enclosure may comprise at least one material selected from the group consisting of: lead-tellurium (Pb-Te), at least one telluride, at least one silicon, at least one silicate, at least one silicide, at least one Si-Ge silicide, at least one polymer, at least one ceramic, at least one skutterudite, CoSb3-skutterudite, germanium, at least one half-Heusler alloy, Mg2(Sn, Si), Sri- x AxZni-yGa y Sni- z X z (A: Ca, Ba, La, Eu; X: Si, Sb), Cai- x A xAl2-yTMySi2 (A=Sr, Ba; TM=Mn, Zn). The TEG can have a thickness of 2 mm to 50 mm, preferably 2 mm to 30 mm, particularly preferably 5 mm to 30 mm.

[0053] The energy recovery enclosure may comprise a plurality of thermoelectric modules. The term "module" as used herein is thus also a broad term, which should be given its usual and common meaning as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. The term may, without limitation, refer in particular to a multi-part embodiment of the energy recovery enclosure.

[0054] The TEG can be flat or ring-shaped, as described, for example, in Mengjun Zhang et al., "Performance comparison of annular and flat-plate thermoelectric generators for cylindrical hot source," https: / / doi.org / 10.1016 / j.egyr.2021.01.008, 2352-4847 / 2021 published by Elsevier Ltd. The geometry and / or modularity of the TEG can depend on the geometry of the reaction tube and / or an expected temperature difference.

[0055] The reaction tube and the energy recovery casing can be arranged concentrically. The reaction tube can be an inner tube, and the energy recovery casing can be arranged further outward. For example, the energy recovery casing can be an outer casing of the device. However, other designs are also conceivable. For example, the device can additionally have an outer casing that at least partially encloses all of the tubes of the device.

[0056] The device can have at least one energy storage device for absorbing the electrical energy from the energy recovery enclosure and / or at least one supply line to a consumer for supplying the electrical energy from the energy recovery enclosure. The absorption can be complete or at least partial. The absorption can comprise storage. The absorption can comprise conversion of the electrical energy into another form of energy. The consumer can, for example, be one or more of a charging station, lighting, another reactor, or any other consumer. Examples include heat exchangers, heat transfer devices, energy storage devices, batteries, or accumulators. The absorbed energy can be used to heat the reaction tube from which the energy was recovered or another reaction tube. Other uses of the recovered energy are also conceivable.The TEG can be designed so that the electrical energy can be extracted directly. The device can therefore be configured so that the temperature directly at the TEG is neither too hot nor too cold. The material used for the TEG can be stable over a wide temperature range, particularly at temperatures to which the feedstock is heated. Alternatively or additionally, the device can include additional elements to protect the TEG, for example, for cooling or pre-cooling. Depending on the TEG materials, the temperature can be adjusted.

[0057] The device may comprise at least one cooling jacket configured to at least partially enclose the energy recovery jacket. The cooling jacket may be configured to cool to room temperature or lower. The term "cooling jacket," as used herein, is a broad term to which its usual and common meaning should be given, as understood by a person skilled in the art. The term is not limited to a specific or adapted meaning. The term may, without limitation, refer in particular to a jacket configured to adjust a temperature difference to a temperature of the reaction tube, in particular a jacket of the reaction tube, for example to a predetermined value. The cooling jacket may comprise at least one cooling medium.

[0058] The term "outer casing" as used herein is a broad term to which its ordinary and customary meaning should be given, as understood by one skilled in the art. The term is not limited to any specific or adapted meaning. The term may, without limitation, refer in particular to an outermost casing of the device, which, in particular, is arranged concentrically. The outer casing may accommodate all elements of the device, in particular all tubes. The outer casing may be configured as a housing. The outer casing may be configured to galvanically insulate the device. The outer casing may have a heat-insulating effect and at least partially reduce heat loss to the outside.Within the scope of the present invention, "at least partially reducing heat loss to the outside" can be understood to mean embodiments with complete thermal insulation and also embodiments in which incomplete heat reduction occurs, for example, up to a predetermined temperature. For example, the outer casing can surround at least a partial region along the heating casing, for example, at least one particularly heat-sensitive and / or heat-sensitive external environmental region. With regard to the materials used, the outer casing can be configured with a specific electrical resistance and thermal conductivity, such as the galvanic insulator described above between the reaction tube and the heating casing.

[0059] In a further aspect, within the scope of the present invention, a plant comprising a device according to the invention is proposed. With regard to the design and definitions of the plant, reference can be made to the description of the device above and below. The plant is selected from the group consisting of: a plant for carrying out at least one endothermic reaction, a heating plant, a preheating plant, a steam cracker, a steam reformer, an alkane dehydrogenation plant, a reformer, a dry reforming plant, a styrene production plant, an ethylbenzene dehydrogenation plant, acetylene production plant, a cracker, a catalytic cracker, and a dehydrogenation plant.

[0060] In a further aspect, the present invention proposes a method for recovering electrical energy using a device according to the invention. The method comprises the following steps:

[0061] Flowing the feedstock through the reaction tube;

[0062] Converting heat generated during a chemical reaction in the reaction tube into electrical energy using the thermoelectric generator of the energy recovery enclosure.

[0063] The method may further comprise a storage step in which the electrical energy is stored in at least one energy storage device and / or supplied to a consumer.

[0064] For embodiments and definitions, reference can be made to the above description of the device. The method steps can be performed in the specified order, whereby one or more of the steps can also be performed at least partially simultaneously, and whereby one or more of the steps can be repeated multiple times. Furthermore, further steps can be performed additionally, regardless of whether they are mentioned in the present description or not.

[0065] In summary, the following embodiments are particularly preferred within the scope of the present invention:

[0066] Embodiment 1 Device comprising a plurality of tubes, wherein at least one of the tubes is configured as a reaction tube for flow through with at least one feedstock, wherein the device has at least one energy recovery casing at least partially enclosing the reaction tube, wherein the energy recovery casing has at least one thermoelectric generator which is configured to convert heat into electrical energy.

[0067] Embodiment 2: Device according to the preceding embodiment, characterized in that the energy recovery enclosure is configured to convert heat generated during an exothermic reaction in the reaction tube into electrical energy. Embodiment 3: Device according to the preceding embodiment, characterized in that the exothermic reaction takes place during decoking and / or oxidation of deposits in the reaction tube.

[0068] Embodiment 4 Device according to one of the preceding embodiments, characterized in that the energy recovery casing comprises at least one material with a thermoelectric quality value ZT of > 0.5, preferably > 0.8, particularly preferably > 1.

[0069] Embodiment 5 Device according to one of the preceding embodiments, characterized in that the energy recovery casing comprises at least one material selected from the group consisting of: lead-tellurium (Pb-Te), at least one telluride, at least one silicon, at least one silicate, at least one silicide, at least one Si-Ge silicide, at least one polymer, at least one ceramic, at least one skutterudite, CoSb3-skutterudite, germanium, at least one half-Heusler alloy, Mg2(Sn, Si), Sri-xA x Zni-yGa y Sni- z X z (A: Ca, Ba, La, Eu; X: Si, Sb), Cai- x A x Al2- y TM ySi2 (A=Sr, Ba;TM=Mn, Zn).

[0070] Embodiment 6 Device according to one of the preceding embodiments, characterized in that the energy recovery enclosure comprises a plurality of thermoelectric modules.

[0071] Embodiment 7 Device according to one of the preceding embodiments, characterized in that the reaction tube and the energy recovery envelope are arranged concentrically, wherein the reaction tube is an inner tube and the energy recovery envelope is arranged further outwards.

[0072] Embodiment 8 Device according to one of the preceding embodiments, characterized in that the energy recovery enclosure is an outer enclosure of the device.

[0073] Embodiment 9 Device according to the preceding embodiment, wherein the device additionally has an outer casing which at least partially encloses all tubes of the device.

[0074] Embodiment 10. Device according to one of the preceding embodiments, characterized in that the reaction tube comprises at least one material selected from the group consisting of: at least one ferritic material, at least one austenitic material, at least one metal, at least one metallic alloy, copper, aluminum, iron, steel, Cr, and / or Ni alloy, graphite, carbon, carbide, silicide. Embodiment 11. Device according to one of the preceding embodiments, characterized in that the reaction tube is an electrically conductive tube.

[0075] Embodiment 12 Device according to one of embodiments 1 to 9, characterized in that the reaction tube is designed as a ceramic tube.

[0076] Embodiment 13 Device according to one of the preceding embodiments, characterized in that the device has at least one current-conducting heating jacket, wherein the device has at least one current or voltage source which is designed to generate an electric current in the heating jacket, which heats the reaction tube by Joule heat which is generated when the electric current passes through the heating jacket.

[0077] Embodiment 14 Device according to the preceding embodiment, characterized in that the heating jacket at least partially surrounds the reaction tube.

[0078] Embodiment 15 Device according to the preceding embodiment, characterized in that the heating jacket directly surrounds the reaction tube and is arranged to transfer its heat generated by electricity to the reaction tube.

[0079] Embodiment 16 Device according to embodiment 13, characterized in that the device comprises at least one galvanic insulator, wherein the galvanic insulator is arranged between the reaction tube and the heating jacket, wherein the galvanic insulator is configured to galvanically insulate the reaction tube from the heating jacket and to transfer heat from the heating jacket to the reaction tube.

[0080] Embodiment 17 Device according to the preceding embodiment, characterized in that the galvanic insulator comprises at least one material selected from the group consisting of ceramic, glass-like, glass-fiber reinforced, plastic-like or resin-like materials, an insulating paint, wherein the galvanic insulator is designed as one or more of a tube, a thin film, a coating, or a layer.

[0081] Embodiment 18 Device according to one of the five preceding embodiments, characterized in that the device has at least one temperature sensor which is configured to determine a temperature of the reaction tube, wherein the device has at least one control unit which is configured to regulate the current or voltage source depending on a temperature measured with the temperature sensor.

[0082] Embodiment 19 Device according to one of the six preceding embodiments, characterized in that the current and / or voltage source comprises a single-phase or multi-phase alternating current and / or single-phase or multi-phase alternating voltage source or a direct current and / or direct voltage source.

[0083] Embodiment 20 Device according to one of the preceding embodiments, characterized in that the device comprises at least one cooling envelope which is configured to at least partially enclose the energy recovery envelope, wherein the cooling envelope is configured to cool to room temperature or lower.

[0084] Embodiment 21 Device according to one of the preceding embodiments, characterized in that the device has at least one energy storage device for receiving the electrical energy from the energy recovery casing and / or at least one supply line to a consumer for supplying the electrical energy from the energy recovery casing.

[0085] Embodiment 22 Device according to one of the preceding embodiments, characterized in that the device is designed to heat the feedstock to a temperature in the range from 200 °C to 1700 °C, preferably 300 °C to 1400 °C, particularly preferably 400 °C to 875 °C.

[0086] Embodiment 23 Device according to one of the preceding embodiments, characterized in that the device comprises a plurality of reaction tubes, wherein the device comprises I reaction tubes, wherein I is a natural number greater than or equal to two, wherein the reaction tubes comprise symmetrical or asymmetrical tubes and / or a combination thereof.

[0087] Embodiment 24 Device according to one of the preceding embodiments, characterized in that the feedstock comprises at least one medium selected from the group consisting of: air, at least one oxygen-containing medium, water, water vapor, and at least one oxidizing medium.

[0088] Embodiment 25 Device according to one of the preceding embodiments, characterized in that the reaction tube is designed for the flow through of at least one feedstock for carrying out at least one endothermic reaction.

[0089] Embodiment 26: A plant comprising at least one device according to one of the preceding embodiments, characterized in that the plant is selected from the group consisting of: a plant for carrying out at least one endothermic reaction, a heating plant, a preheating plant, a steam cracker, a steam reformer, an alkane dehydrogenation plant, a reformer, a dry reforming plant, a styrene production plant, an ethylbenzene dehydrogenation plant, an acetylene production plant, a cracker, a catalytic cracker, and a dehydrogenation plant. Embodiment 27: A method for recovering electrical energy using a device according to one of the preceding embodiments relating to a device, the method comprising the following steps:

[0090] - Flowing the feedstock through the reaction tube;

[0091] - Converting heat generated during a chemical reaction in the reaction tube into electrical energy using the thermoelectric generator of the energy recovery enclosure.

[0092] Short description of the characters

[0093] Further details and features of the invention will become apparent from the following description of preferred embodiments, particularly in conjunction with the subclaims. The respective features can be implemented individually or in combination with one another. The invention is not limited to the embodiments. The embodiments are illustrated schematically in the figures. Identical reference numerals in the individual figures designate identical or functionally identical elements, or elements that correspond to one another in terms of their functions.

[0094] In detail:

[0095] Figures 1a and 1b show embodiments of a device according to the invention with a reaction tube;

[0096] Figures 2a and 2b show embodiments of the device according to the invention with a plurality of reaction tubes;

[0097] Figures 3a and 3b show embodiments of the device according to the invention comprising two heating zones;

[0098] Figures 4a to 4y show embodiments of the device according to the invention with a modular system with tube types for possible reaction tubes and examples of variations;

[0099] Figures 5a and 5b show embodiments of the device according to the invention with a cooling circuit;

[0100] Figures 6a and 6b show embodiments of the device according to the invention analogous to Figures 1a and 2a with a rectangular tube design;

[0101] Figures 7a and 7b show embodiments of the device according to the invention with a rectangular tube design with cooling circuit; and

[0102] Figures 8a to 8d show embodiments of the device according to the invention with energy storage devices and application examples.

[0103] Examples of implementation

[0104] Figures 1a and 1b show a schematic representation of two embodiments of a device 110 according to the invention, each with a reaction tube 112. The device 110 comprises a plurality of tubes. For example, in the embodiments shown in Figures 1a and 1b, the device 110 comprises three concentrically arranged hollow cylindrical tubes. At least one of the tubes is configured as a reaction tube 112 for the flow of at least one feedstock. The device 110 can have at least one reactive chamber 111.The device 110 can be used in a plant selected from the group consisting of: a plant for carrying out at least one endothermic reaction, a plant for heating, a plant for preheating, a steam cracker, a steam reformer, a plant for alkane dehydrogenation, a reformer, a plant for dry reforming, a plant for styrene production, a plant for ethylbenzene dehydrogenation, production of acetylene, a cracker, a catalytic cracker, a plant for dehydrogenation.

[0105] The reaction tube 112 can be configured as a flow-through tube. The reaction tube 112 can be configured for the feedstock to flow through it. The reaction tube 112 can be configured so that at least one chemical reaction and / or a partial reaction can take place in the reaction tube. The reaction tube 112 can comprise at least one pipeline and / or at least one pipeline segment 114 and / or at least one pipeline coil. A pipeline segment 114 can be a subsection of a pipeline.

[0106] The reaction tube can, for example, be configured to heat the feedstock. The reaction tube 112 can be a reactor and / or a furnace or a part thereof. For example, the reaction tube 112 can be designed as a reactor of a combustion furnace and / or an electrically heatable reactor. For example, the reaction tube 112 can be designed as a reactor of a combustion furnace, as described, for example, in H. Zimmermann and R. Walzl, "Ethylene", Ullmann's Encyclopedia of Industrial Chemistry, 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, DOI: 10.1002 / 14356007.a10_045.pub3, EP 2 653 524 A1, US 4,361,478 A, EP 0 245 839 A1 or EP3415587A1. For example, the reaction tube 112 can be designed as an electrically heatable reactor, as described, for example, in WO 2015 / 197181 A1, WO 2020 / 035575 A1, and WO 2020 / 035574 A1.

[0107] The geometry and / or surfaces and / or material of the reaction tube 112 can depend on the feedstock. Alternatively or additionally, the geometry and / or surfaces and / or material of the reaction tube 112 can depend on a desired reaction and / or avoidance of a specific reaction and / or optimization of the reaction and / or other factors. For example, the reaction tube 112 can be designed as a hollow cylinder. For example, as shown in Figures 1a to 3b, all tubes of the device 110 can be designed as hollow cylinders. The tubes can be completely cylindrical or can have non-cylindrical sections. The hollow cylinder can, for example, be a circular cylinder with a radius r and a length h, also referred to as the height. The circular cylinder can have a bore along an axis. Deviations from a circular cylinder geometry are also conceivable.For example, the tube can have an elliptical cross-sectional area. Other geometries are also conceivable.

[0108] The feedstock can in principle be any flowable medium. The feedstock can be liquid or gaseous. The feedstock can comprise at least one medium selected from the group consisting of: air, at least one oxygen-containing medium, water, steam, and at least one oxidizing medium. Other feedstocks are also conceivable. In the plants listed above for carrying out at least one endothermic reaction, a number of side reactions occur which can, for example, lead to coking of plant components, in particular the reaction tubes 112. It is therefore customary, for example at fixed or regular intervals, to carry out exothermic reactions to burn off the coking, in particular a so-called decoking of the plant.During decoking, the feedstock, also referred to as decoking gas, can be fed into the reaction tube 112 and the cokes can be burned off in at least one exothermic reaction.

[0109] The reaction tube 112 can be an electrically conductive, in particular a metallic, reaction tube 112, or an electrically non-conductive reaction tube 112. In the embodiment of Figure 1a, the reaction tube can be an electrically conductive, metallic reaction tube. The reaction tube 112 can have a specific electrical resistance of less than 10 1 Q m. The reaction tube 112 may have a specific electrical resistance p of 1 »10' 8 m < p < 10 1m. For example, the reaction tube 112 may comprise at least one material selected from the group consisting of: at least one ferritic material, at least one austenitic material, at least one metal, at least one metallic alloy, copper, aluminum, iron, steel, Cr, and / or Ni alloy, graphite, carbon, carbide, silicide.

[0110] However, configurations of the reaction tube 112 as electrically non-conductive tubes or poorly conductive tubes are also conceivable, as shown in Figure 1b. For example, the reaction tube 112 can be made of a ceramic or materials with a similar specific resistance. The reaction tube 112 can be configured as a galvanic insulator. The reaction tube 112 can have a specific electrical resistance of more than 10 5 Qm. The reaction tube 112 may have a specific electrical resistance p of 1x10 5 m < p < 1x10 20m, preferably from 1x10 5 Q m < p < 1x10 14 Q m. For example, the reaction tube 112 can be configured as a ceramic tube. For example, the reaction tube 112 can comprise at least one material selected from the group consisting of: MgO, Al2O3, B nitride, Al nitride, Al silicate (mullite), ZrO2, Mg-Al silicate (cordierite), Mg silicate (steatite), Si nitride.

[0111] The device 110 can have at least one heating jacket 129, as shown in Figures 1a and 1b. The device 110 can have at least one current or voltage source 126, which is configured to generate an electric current in the heating jacket 129, which heats the reaction tube 112 through Joule heating, which is generated when the electric current passes through the heating jacket 129. The heating jacket 129 can be a jacket configured to transfer energy supplied to it in the form of heat to the reaction tube 112. The heating jacket 129 can at least partially surround the reaction tube 112. The geometry and / or material of the heating jacket 129 can be adapted to the reaction tube 112 to be heated. This makes energy-efficient heating of the reaction tube 112 possible.

[0112] The heating jacket 129 can comprise at least one material selected from the group consisting of ferritic or austenitic materials, e.g., CrNi alloy, CrMo, or ceramic. For example, the heating jacket can be made of at least one metal and / or at least one alloy, such as copper, aluminum, iron, steel or Cr, Ni alloys, graphite, carbon, carbides, or silicides. Semiconductors are also conceivable as materials for the heating jacket, for example, Ge, Si, selenides, tellurides, arsenides, and antimonide.

[0113] The heating jacket 129 can be a conductive heating jacket. The heating jacket 129, in particular with a connected current or voltage source 126, can have a specific electrical resistance p of 1x10 -8 m < p < 10 5m. The heating jacket 129 can have a thermal conductivity A of 10 W / (mK) < A < 6000 W / (mK), preferably 20 W / (mK) < A < 5000 W / (mK). The heating jacket 129 can be temperature-resistant in a range up to 2000°C, preferably up to 1300°C, particularly preferably up to 1000°C.

[0114] As stated above, the device 110 can have at least one current or at least one voltage source 126 configured to generate an electric current in the heating jacket 129, which heats the reaction tube 112 through Joule heat generated when the electric current passes through the heating jacket. The current and / or voltage source 126 can comprise a single-phase or multi-phase alternating current and / or single-phase or multi-phase alternating voltage source, or a direct current and / or direct voltage source. The device 110 can have at least one supply and discharge line 127, which electrically connects the current and / or voltage source 126 to the heating jacket 129, in particular via electrical connections 128.

[0115] The current generated in the heating jacket 129 can heat the reaction tube 112 through Joule heat, which is generated when the electric current passes through the heating jacket 129, to heat the feedstock. Heating the reaction tube 112 can comprise at least one process that leads to a change in the temperature of the reaction tube 112, in particular an increase in the temperature of the reaction tube 112, and / or to the temperature of the reaction tube 112 remaining substantially constant, for example, when the reaction taking place in the reaction tube 112 absorbs the same amount of heat as it receives. The feedstock can be heated, for example, to a predefined or predetermined temperature value. The device 110 can be configured to heat the feedstock to a temperature in the range from 200°C to 1700°C, preferably from 300°C to 1400°C, particularly preferably from 400°C to 875°C.However, other temperatures and temperature ranges are also conceivable. The reaction tube 112 can be configured to at least partially absorb the Joule heat generated by the heating jacket 129 and at least partially transfer it to the feedstock. For example, at least one endothermic reaction can take place in the reaction tube 112. The endothermic reaction can include heating and / or preheating of the feedstock. In particular, the feedstock can be heated in the reaction tube 112.

[0116] The heating jacket 129 can be arranged such that the heating jacket 129 at least partially surrounds the reaction tube 112. For example, the heating jacket 129 can completely surround the reaction tube 112 or only partial areas of the reaction tube 112. For example, the reaction tube 112 can be arranged as an inner cylinder in the heating jacket 129. For example, several heating jackets 129 can be arranged in a clamp-like manner around the reaction tubes 112. For example, the reaction tube 112 can be spiral-shaped, and the heating jacket 129 can be arranged around the reaction tube 112. Embodiments are also conceivable in which different or similar heating jackets 129 are arranged around different areas of a reaction tube 112 or multiple reaction tubes 112, enabling individual heating of the areas of the reaction tube 112 or the reaction tubes 112.

[0117] As shown in Figure 1b, the heating jacket 129 can directly surround the reaction tube 112 and be configured to transfer its electrically generated heat to the reaction tube 112. The reaction tube 112 and the heating jacket 129 can be arranged as adjacent tubes of the device 110. In particular, no further tube can be arranged between the reaction tube 112 and the heating jacket 129.

[0118] Figure 1a shows another arrangement of reaction tube 112 and heating jacket 129. In this arrangement, the heating jacket 129 indirectly surrounds the reaction tube 112. As explained above, the reaction tube 112 shown in Figure 1a can be an electrically conductive, in particular metallic, reaction tube 112. The device 110 can have at least one, in particular thermally conductive, galvanic insulator 124. The galvanic insulator 124 can be arranged between the reaction tube 112 and the heating jacket 129. The galvanic insulator 124 can be configured to galvanically insulate the reaction tube 112 from the heating jacket 129 and to transfer heat from the heating jacket 129 to the reaction tube 112. The galvanic insulator 124 can have a specific electrical resistance p of 1x10 5 Q m < p < 1x10 14m. A heat transfer coefficient can be high. The galvanic insulator 124 can have a thermal conductivity A of 10 W / (mK) < A < 6000 W / (mK), preferably of 20 W / (mK) < A < 5000 W / (mK). The galvanic insulator 124 can comprise at least one material selected from the group consisting of ceramic, glass-like, glass-fiber-reinforced, plastic-like or resin-like materials, such as, for example, ceramic, steatite, porcelain, glass, glass-fiber-reinforced plastic, epoxy resin, thermoset, elastomers, as well as electrically sufficiently insulating liquids, an insulating paint. The galvanic insulator 124 can be designed as one or more of a tube, a thin foil, a coating, or a layer. The galvanic insulator can, for example, be a flexible galvanic insulator, for example a thin foil. This allows for expansion when there are temperature differences.The galvanic insulator 124 can be configured to transfer heat from the live heating jacket 129 to the reaction tube 112. The galvanic insulator 124 can galvanically insulate the reaction tube 112 from the heating jacket 129.

[0119] Figures 2a and 2b show embodiments with a plurality of reaction tubes 112. With regard to the design of the further elements of the device 110 of Figure 2a, reference can be made to the description of Figure 1a, and with regard to the design of the further elements of the device 110 of Figure 2b, reference can be made to the description of Figure 1b. The device 110 can have I reaction tubes 112, where I is a natural number greater than or equal to two. For example, the device 110 can have at least two, three, four, five, or even more reaction tubes 112. The device 110 can, for example, have up to one hundred reaction tubes 112. For example, the reaction tubes 112 can be arranged within the heating jacket 129. For example, the reaction tube 112 can be spiral-shaped, and the heating jacket can be arranged around the reaction tube.Embodiments are also conceivable in which different or similar heating jackets are arranged around different regions of a reaction tube or several reaction tubes and individual heating of the regions of the reaction tube or the reaction tubes can be made possible.

[0120] The reaction tubes 112 can be interconnected and thus form a pipe system 118. The pipe system 118 can have supply and discharge pipes. The pipe system 118 can have at least one inlet 120 for receiving the feedstock. The pipe system 118 can have at least one outlet 122 for discharging the feedstock. The reaction tubes 112 can be fluidly connected to one another. Thus, the reaction tubes 112 can be arranged and connected such that the feedstock flows through the reaction tubes 112 one after the other. Several or all of the reaction tubes 112 can be configured in series and / or in parallel. The reaction tubes 112 can be connected in parallel such that the feedstock can flow through at least two reaction tubes 112 in parallel. The reaction tubes 112, in particular the parallel-connected pipes, can be configured to transport different feedstocks in parallel.In particular, for transporting different feedstocks, the pipes connected in parallel can have different geometries and / or surfaces and / or materials. In particular for transporting a feedstock, several or all of the reaction tubes 112 can be configured in parallel so that the feedstock can be distributed between those parallel-configured pipes. Combinations of serial and parallel connections are also conceivable. When using electrically conductive pipes as reaction tubes 112, the inlet and outlet pipes can be galvanically separated from one another. For this purpose, the device 110 can have at least one insulator, in particular a plurality of insulators. The galvanic isolation between the respective pipes and the inlet and outlet pipes can be ensured by the insulators. The insulators can ensure a free flow of the feedstock.

[0121] As schematically illustrated in Figures 1a and 1b, the device 110 has at least one energy recovery enclosure 130 that at least partially encloses the reaction tube 112. The energy recovery enclosure 130 can, for example, completely enclose the reaction tube 112. The energy recovery enclosure 130 can be an enclosure configured to at least partially recover the energy used to heat the feedstock. The energy recovery enclosure 130 has at least one thermoelectric generator (TEG) configured to convert heat into electrical energy. The conversion can be a thermoelectric energy conversion. The conversion of heat into energy can occur at least partially. For example, the TEG can have an efficiency of 5-10%.

[0122] The TEG can be a device configured to convert heat flows (temperature differences) into electrical energy using the so-called Seebeck effect. The energy recovery casing 130 can be configured to convert heat generated in the reaction tube during an exothermic reaction, particularly during decoking, into electrical energy. A chemical reaction can be considered exothermic if it releases more energy than was initially supplied to it as activation energy. The exothermic reaction can occur during decoking and / or oxidation of the deposits in the reaction tube. For example, a temperature difference can be created by a temperature of 1000°C in the reaction tube 112 and a temperature of 20°C on an outer casing of the device 110, for example after cooling.

[0123] The TEG can, for example, be designed as described in US 2014 / 0238459 A1 , Mengjun Zhang et al., “Performance comparison of annular and flat-plate thermoelectric generators for cylindrical hot source“, https: / / doi.Org / 10.1016 / j.egyr.2021.01.008, 2352-4847 / 2021 published by Elsevier Ltd.

[0124] The energy recovery enclosure 130 may comprise at least one material having a thermoelectric quality value ZT of > 0.5, preferably > 0.8, particularly preferably > 1. The thermoelectric quality value can be described as ZT=(a 2(T) •O(T)»T) / K(T), where a is the Seebeck coefficient, a is the electrical conductivity, K is the specific thermal conductivity of the material. The energy recovery enclosure 130 may comprise at least one material selected from the group consisting of: lead-tellurium (Pb-Te), at least one telluride, at least one silicon, at least one silicate, at least one silicide, at least one Si-Ge silicide, at least one polymer, at least one ceramic, at least one skutterudite, CoSb3-skutterudite, germanium, at least one half-Heusler alloy, Mg2(Sn,Si), Sri- x AxZni-yGa y Sni- z X z (A: Ca, Ba, La, Eu; X: Si, Sb), Cai- x A x Al2-yTMySi2 (A=Sr, Ba; TM=Mn, Zn). The TEG can have a thickness of 2 mm to 50 mm, preferably 2 mm to 30 mm, more preferably 5 mm to 30 mm. The energy recovery enclosure 130 can include a plurality of thermoelectric modules.

[0125] The TEG can be flat or annular, as described, for example, in Mengjun Zhang et al., "Performance comparison of annular and flat-plate thermoelectric generators for cylindrical hot source," https: / / doi.org / 10.1016 / j.egyr.2021.01.008, 2352-4847 / 2021 published by Elsevier Ltd. The geometry and / or modularity of the TEG can depend on the geometry of the reaction tube 112 and / or on an expected temperature difference.

[0126] The device 110 can have at least one energy storage device, shown in Figures 1a and 1b as an electrical resistor 132, for absorbing the electrical energy from the energy recovery casing 130 and / or at least one supply line to a consumer for supplying the electrical energy from the energy recovery casing 130. The absorption can be complete or at least partial. The absorption can comprise storage. The absorption can comprise conversion of the electrical energy into another form of energy. The TEG can be designed such that the electrical energy can be extracted directly. The device 110 can therefore be designed such that the temperature directly at the TEG is neither too hot nor too cold. The material used for the TEG can be stable over a temperature range, in particular at temperatures to which the feedstock is heated.Alternatively or additionally, the device 110 can comprise additional elements for protecting the TEG, for example, for cooling or pre-cooling. Depending on the materials of the TEGs, the temperature can thus be adjusted.

[0127] The reaction tube 112 and the energy recovery enclosure 130 can be arranged concentrically. The reaction tube 112 can be an inner tube, and the energy recovery enclosure 130 can be arranged further outward. For example, the energy recovery enclosure 130 can be an outer enclosure of the device 110, as shown in Figures 1a, 1b, 2a, 2b, 3a, and 3b. However, other embodiments are also conceivable. For example, the device 110, as shown in Figures 5a and 5b, can additionally have a cooling enclosure 146, which at least partially encloses all of the tubes of the device 110.

[0128] The device 110 can have a plurality of heating zones 144. For example, the device 110 can have two or more heating zones 144. Each heating zone 144 can comprise at least one heating jacket 129. The heating jackets 129 can be connected by electrical connections 133. The device 110 can also have regions in which no heating of the feedstock takes place, for example, pure transport zones. Figures 3a and 3b show embodiments with two heating zones 144. For example, the two heating zones can be configured as two reactors or two heat exchangers or one reactor and one heat exchanger. With regard to the design of the further elements of the device 110 in Figure 3a, reference can be made to the description of Figure 1a, and with regard to the design of the further elements of the device 110 in Figure 3b, reference can be made to the description of Figure 1b.In Figure 3a, the reaction tube 112 is configured as a metallic cylinder with an outer arrangement of the TEG. In Figure 3b, the reaction tube 112 is configured as a ceramic cylinder with an outer arrangement of the TEG.

[0129] Figures 4a to 4y show embodiments of the device 110 with a modular system of tube types for possible reaction tubes 112 and examples of variations. As explained above, the device 110 can have a plurality of reaction tubes 112. The reaction tubes 112 can, for example, be designed differently in terms of diameter, and / or length, and / or geometry. The reaction tubes 112 can have symmetrical and / or asymmetrical tubes and / or combinations thereof. In a purely symmetrical design, the device 110 can have reaction tubes 112 of an identical tube type.The pipe type can be characterized by at least one feature selected from the group consisting of: a horizontal configuration of the pipe; a vertical configuration of the pipe; a length at the inlet (11) and / or outlet (12) and / or transition (13); a diameter at the inlet (d1) and outlet (d2) and / or transition (d3); number n of passes; length per pass; diameter per pass; geometry; surface; and material. The device 110 can have a combination of at least two different pipe types connected in parallel and / or in series. For example, the device can have pipes of different lengths at the inlet (11) and / or outlet (12) and / or transition (13). For example, the device 110 can have pipes with an asymmetry of the diameters at the inlet (d1) and / or outlet (d2) and / or transition (d3).For example, the device 110 can have tubes with a different number of passes. For example, the device can have tubes with passes of different lengths per pass and / or different diameters per pass. In principle, any combination of all tube types in parallel and / or in series is conceivable. The device 110 can have a plurality of inlets 120 and / or outlets 122 and / or production streams. The reaction tubes 112 of different or identical tube types can be arranged in parallel and / or in series with multiple inlets 120 and / or outlets 122. Possible tubes for reaction tubes 112 can be present in various tube types in the form of a modular system 134 and can be selected and combined as desired depending on the intended use.Using tubes of different types can enable more precise temperature control, and / or reaction adjustment in the presence of fluctuating feed, and / or selective reaction yield, and / or optimized process technology. The tubes can have identical or different geometries, surfaces, and / or materials.

[0130] Figures 4a to 4y show exemplary possible embodiments of tube or cylinder types in a schematic representation. The tube type can be divided into the following categories, with all conceivable combinations of the categories being possible:

[0131] - Category A indicates a course of the reaction tube 112 and / or a tube segment 114, where A1 indicates a tube or cylinder type with a horizontal course and A2 indicates a tube type with a vertical course, i.e. a course perpendicular to the horizontal course.

[0132] - Category B indicates a ratio of lengths in the inlet (11 ) and / or outlet (I2) and / or

[0133] Diameter at the inlet (d1) and / or outlet (d2) and / or transition (d3), whereby six different combination possibilities are listed in the kit 134.

[0134] - Category C specifies ratios of lengths at the inlet (11) and / or outlet (12) and lengths of passages. All combinations are conceivable here, which are designated Ci here.

[0135] - Category F includes the number of electrodes: F1 indicates that the number of electrodes is < 2, for example, for a direct current or alternating current source. F2 indicates that the number of electrodes is > 2, for example, for a three-phase source.

[0136] Figures 4b to 4y show exemplary embodiments according to the invention of combinations of reaction tubes 112 and / or pipe segments 114 of the same and / or different pipe types. Figure 4b shows a combination of reaction tubes 112 with three horizontal pipelines 112 and / or pipeline segments 114 of pipe type A1, which are arranged one after the other. Figure 4c shows two vertical pipes of pipe type A2 connected in parallel and a downstream reaction tube 112 and / or a downstream pipeline segment 114, also of pipe type A2. Figure 4d shows a plurality of reaction tubes 112 and / or pipeline segments 114 of pipe type A2, all of which are connected in parallel. Figure 4e shows an embodiment in which a plurality of pipe types of category B are arranged one after the other.The reaction tubes 112 and / or pipeline segments 114 can be identical or different pipe types of category B, which is designated by Bi. Figure 4f shows an embodiment with six reaction tubes 112 and / or pipeline segments 114 of category B, wherein two reaction tubes 112 and / or pipeline segments 114 are arranged in two parallel strands and two further reaction tubes 112 and / or pipeline segments 114 are connected downstream. Figure 4g shows an embodiment with pipelines 112 and / or pipeline segments 114 of category C, wherein two pipelines 112 and / or pipeline segments 114 are connected in parallel and one reaction tube 112 and / or one pipeline segment 114 is connected downstream. Mixed forms of categories A, B and C are also possible, as shown in Figures 4h to 4m.

[0137] As stated above, the device 110 may have a plurality of inlets 120 and / or outlets 122 and / or production streams. The reaction tubes 112 and / or pipeline segments 114 of different or identical tube types may be arranged in parallel and / or in series with multiple inlets 120 and / or outlets 122, as shown, for example, in Figures 4k and 4m.

[0138] Figures 4n to 4p show exemplary combinations of reaction tubes 112 and / or of pipeline segments 114 of categories A and Fi. Figures 4q and 4r show exemplary combinations of reaction tubes 112 and / or of pipeline segments 114 of categories B and Fi. Figure 4s shows an exemplary combination of reaction tubes 112 and / or of pipeline segments 114 of categories C and Fi. Figure 4t shows an exemplary combination of reaction tubes 112 and / or of pipeline segments 114 of categories A, B, C and Fi. Figure 4u shows an exemplary combination of reaction tubes 112 and / or of pipeline segments 114 of categories A, C and Fi. Figure 4v shows an exemplary combination of reaction tubes 112 and / or of pipeline segments 114 of categories B, C and Fi. Figures 4w and 4y show exemplary combinations of reaction tubes 112 and / or of pipeline segments 114 of categories A, B, C and Fi.Figure 4x shows an exemplary combination of reaction tubes 112 and / or pipeline segments 114 of categories A, B, and Fi. The reaction tubes 112 and / or pipeline segments 114 of different or identical pipe types of categories A, B, C, and Fi can be arranged in parallel and / or in series with multiple inlets 120 and / or outlets 122. Examples of a plurality of inlets 120 and / or outlets 122 and / or production streams are shown in Figures 4o, 4p, 4r, 4s, 4v to 4y. The lines can represent a feed stream, but they can also indicate the electrical connections.

[0139] Figures 5a and 5b show embodiments of the device according to the invention with a cooling circuit comprising the cooling jacket 146. The cooling jacket 146 can be configured to at least partially enclose the energy recovery jacket 130. The cooling jacket 146 can be configured to cool to room temperature or lower. The cooling jacket 146 can be configured to set a temperature difference to a temperature of the reaction tube 112, in particular a jacket of the reaction tube 112, for example to a predetermined value. The cooling jacket 146 can have at least one cooling medium. With regard to the design of the further elements of the device 110 in Figure 5a, reference can be made to the description of Figure 1a, and with regard to the design of the further elements of the device 110 in Figure 5b, reference can be made to the description of Figure 1b. In Figure 5a, the reaction tube 112 is designed as a metallic cylinder.The TEG is arranged concentrically outward, surrounded by the cooling jacket 146. In Figure 5b, the reaction tube 112 is designed as a ceramic cylinder. The TEG is arranged concentrically outward, surrounded by the cooling jacket 146.

[0140] Figures 6a, 6b, 7a, and 7b show embodiments in which the tubes of the device 110, with the exception of the reaction tube 112, or the reaction tubes 112, have a rectangular geometry. The reaction tube 112 is also designed as a hollow cylinder in these figures. Figure 6a shows a design analogous to the device 110 of Figure 1a. Figure 6b shows a design analogous to the device 110 of Figure 2a. Figures 7a and 7b show an embodiment with an additional cooling jacket 146. Figure 7a shows a design analogous to the device 110 of Figure 5a. Figure 7b shows a design analogous to Figure 7a, but with a plurality of reaction tubes 112.

[0141] Figures 8a to 8d show application examples of the device. Purely by way of example, the device 110 in Figures 8a to 8d is shown analogously to the device 110 in Figure 1a. However, any other described embodiment of the device 110 is conceivable. As explained above, the device 110 can have at least one energy storage device for receiving the electrical energy from the energy recovery enclosure 130 and / or at least one supply line to a consumer for supplying the electrical energy from the energy recovery enclosure 130, schematically represented by an electrical resistor 132. In Figure 8a, the consumer is shown as an arbitrary consumer 148. The consumer 148 can, for example, be one or more of a charging station, a lighting system, another reactor, or any other arbitrary consumer. Examples include heat exchangers, heat transfer units, energy storage devices, batteries, or accumulators.Figure 8b, for example, shows a consumer in the form of a further device 110, in which the energy can be used to heat the heating envelope of the further device 110. Figure 8c shows an embodiment of two devices 110 (each analogous to the device 110 of Figure 1a), in which the devices 110 are each configured to supply recovered energy to the electrical resistance 132. This can be used, for example, to heat the other reactor. Figure 8d shows an example with a plurality of identical or different consumers 148, which can be operated at least partially using the recovered energy. Other uses of the recovered energy are also conceivable.

[0142] List of reference symbols

[0143] device

[0144] Reactive room

[0145] reaction tube

[0146] Pipe segment

[0147] Pipe system

[0148] inlet

[0149] Outlet galvanic isolator

[0150] Voltage / current source electrical supply and discharge electrical connections heating jacket

[0151] Energy recovery sheath electrical resistance electrical connection

[0152] Construction kit

[0153] Heating zone

[0154] Cooling wrap

[0155] Any consumer

Claims

Patent claims 1. Device (110) comprising a plurality of tubes, wherein at least one of the tubes is configured as a reaction tube (112) for flow with at least one feedstock, wherein the device (110) has at least one energy recovery enclosure (130) at least partially enclosing the reaction tube (112), wherein the energy recovery enclosure (130) has at least one thermoelectric generator configured to convert heat into electrical energy.

2. Device (110) according to the preceding claim, characterized in that the energy recovery casing (130) is configured to convert heat generated during an exothermic reaction in the reaction tube (112) into electrical energy.

3. Device (110) according to the preceding claim, characterized in that the exothermic reaction takes place during a decoking and / or oxidation of deposits of the reaction tube (112).

4. Device (110) according to one of the preceding claims, characterized in that the energy recovery covering (130) comprises at least one material with a thermoelectric efficiency ZT of > 0.5, preferably > 0.8, particularly preferably > 1.

5. Device (110) according to one of the preceding claims, characterized in that the energy recovery casing (130) comprises at least one material selected from the group consisting of: lead tellurium (Pb-Te), at least one telluride, at least one silicon, at least one silicate, at least one silicide, at least one Si-Ge silicide, at least one polymer, at least one ceramic, at least one skutterudite, CoSb3 skutterudite, germanium, at least one half-Heusler alloy, Mg2(Sn, Si), Sri- x AxZni-yGa y Sni- z X z (A: Ca, Ba, La, Eu; X: Si, Sb), Cai- x A x Al2-yTMySi2 (A=Sr, Ba; TM=Mn, Zn).

6. Device (110) according to one of the preceding claims, characterized in that the energy recovery casing (130) comprises a plurality of thermoelectric modules.

7. Device (110) according to one of the preceding claims, characterized in that the reaction tube (112) and the energy recovery casing (130) are arranged concentrically, wherein the reaction tube (112) is an inner tube and the energy recovery casing (130) is arranged further outwards.

8. Device (110) according to one of the preceding claims, characterized in that the reaction tube (112) comprises at least one material selected from the group consisting of: at least one ferritic material, at least one austenitic material material, at least one metal, at least one metallic alloy, copper, aluminium, iron, steel, Cr, and / or Ni alloy, graphite, carbon, carbide, silicide, or that the reaction tube (112) is designed as a ceramic tube.

9. Device (110) according to one of the preceding claims, characterized in that the device (110) has at least one electrically conductive heating envelope (129), wherein the device has at least one current or voltage source (126) which is configured to generate an electric current in the heating envelope (129) which heats the reaction tube (112) by Joule heating, which is generated when the electric current passes through the heating envelope (129).

10. Device (110) according to the preceding claim, characterized in that the heating envelope (129) at least partially surrounds the reaction tube (112), wherein the heating envelope (129) directly surrounds the reaction tube (112) and is configured to transfer its electrically generated heat to the reaction tube (112), and / or wherein the device (110) has at least one galvanic insulator (124), wherein the galvanic insulator (124) is arranged between the reaction tube (112) and the heating envelope (129), wherein the galvanic insulator (124) is configured to galvanically isolate the reaction tube (112) from the heating envelope (129) and to transfer heat from the heating envelope (129) to the reaction tube (112).

11. Device (110) according to one of the preceding claims, characterized in that the device has at least one cooling envelope (146) which is configured to at least partially enclose the energy recovery envelope (130), wherein the cooling envelope (146) is configured to cool to room temperature or below.

12. Device (110) according to one of the preceding claims, characterized in that the device (110) is configured to heat the feedstock to a temperature in the range of 200 °C to 1700 °C, preferably 300 °C to 1400 °C, particularly preferably 400 °C to 875 °C.

13. Device (110) according to one of the preceding claims, characterized in that the reactant comprises at least one medium selected from the group consisting of: air, at least one oxygen-containing medium, water, water vapor, and at least one oxidizing medium.

14. Device (110) according to one of the preceding claims, characterized in that the reaction tube (112) is configured for the flow of at least one reactant to carry out at least one endothermic reaction.

15. Plant comprising at least one device (110) according to one of the preceding claims, characterized in that the plant is selected from the group consisting of: a plant for carrying out at least one endothermic reaction, a heating plant, a preheating plant, a steam cracker, a steam reformer, an alkane dehydrogenation device, a reformer, a dry reforming device, a styrene production device, an ethylbenzene dehydrogenation device, production of acetylene, a cracker, a catalytic cracker, a dehydrogenation device. A method for recovering electrical energy using a device (110) according to any of the preceding claims relating to a device, wherein the method comprises the following steps: - passing the feedstock through the reaction tube (112); - Converting heat generated during a chemical reaction in the reaction tube (112) into electrical energy using the thermoelectric generator of the energy recovery casing (130).

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