Catalyst support and heating element

Abstract

An electrically heated chemical reactor comprising a reaction vessel, a combined catalyst support and heating element, and catalyst supported by the combined catalyst support and heating element. Whe

Description

Field The present invention generally relates to chemical reactors, particularly to catalyst based chemical reactors for performing chemical reactions at elevated temperatures using a catalyst. Background Production of chemical compounds is a major global market. Energy consumption and emissions are two key considerations of such chemical production processes. Many chemical reactors, particularly those operating at elevated temperatures significantly above room temperature, do not achieve high levels of energy efficiency and may give rise to emission of unwanted by-products. Furthermore, many reactors are bulky or require large scale industrial infrastructure to support them. As such, chemical reactor design faces many challenges. Compromises are often needed between providing a chemical reactor that is both energy and process efficient, but is also compact and cost effective to produce, install and operate. Summary The aspects of the present invention are defined in the independent claims. Some preferred features are defined in the dependent claims. According to a first example of the present application is an electrically heated chemical reactor comprising: a reaction vessel; a combined catalyst support and heating element; and a catalyst supported by the combined catalyst support and heating element; wherein the combined catalyst support and heating element comprises at least one carbon based elongate support structure. The elongate support structure may be or comprise a carbon based filament, fibre, tow, rod or the like. The at least one elongate support structure (e.g. filament) may be a heating element (e.g. a heating filament), e.g. for heating an interior of the reaction vessel and / or for heating reactants of a chemical reaction to be performed in the chemical reactor. The at least one elongate support structure may support the catalyst. The catalyst may be directly or indirectly disposed on the at least one elongate support structure. The combined catalyst support and heating element, e.g. the at least one elongate support structure thereof, may be disposed in the reaction vessel or otherwise configured to heat the reaction vessel or reactants that are provided or to be provided therein. The combined catalyst support and heating element, e.g. the at least one elongate support structure thereof, may be configured to provide at least some or all of the heat for the chemical reaction, e.g. to heat reactants, which may be in the reaction vessel when in use. The combined catalyst support and heating element, e.g. the at least one elongate support structure thereof, may be configured for direct electrical heating, e.g. of the interior of the reaction vessel. The combined catalyst support and heating element, e.g. the at least one elongate support structure thereof, may be a Joule heating element or other electric heating element, e.g. configured to heat via Joule heating. The at least one elongate support structure may be connected to at least a pair of electrical connectors and may be configured to conduct electricity from at least one of the electrical connectors to at least one other of the electrical connectors in order to provide the heat. The at least one elongate support structure may be resistive, e.g. to provide electrical resistance to flow of the electricity from at least one of the electrical connectors to at least one other of the electrical connectors, e.g. in order to provide the heat. The use of a carbon based elongate support structure, such as a filament, fibre, tow or rod, rather than other forms such as a solid or foamed material or the like, has been found to better facilitate removal of reaction product and improve efficiency. The at least one elongate support structure (e.g. filament) may be a flexible elongate support structure (e.g. a flexible filament). The elongate support structure may have a high aspect ratio, e.g. a length of at least an order of magnitude or two, three, four, five, six, or higher orders of magnitude more than the diameter of the at least one elongate support structure. The chemical reactor may comprise a core, which may be an elongate core. The reaction vessel may be an elongate reaction vessel. The core may be provided within the reaction vessel and / or may extend along a long direction of the reaction vessel, e.g. a long direction of the core may be generally parallel to a long direction of the reaction vessel. The at least one elongate support structure may be a non-linear support structure, e.g. a coiled, wound or helical structure. Each of the at least one elongate support structures (e.g. of the at least one filaments) may be wound, e.g. a wound filament, and may be wound around the core, which may be a mandrel, tube or cylinder. The electrical connectors may be connected to the at least one elongate support structure at locations that are spaced apart along the long axis of the at least one elongate support structure and / or the core. The core may be metallic and / or ceramic, e.g. a metal coated with ceramic coating. The core may be thermally conductive. The core may be a solid core, such as a solid stainless steel core. The at least one elongate support structure may be both electrically conductive and heat conductive. The core may be an elongate core. The core may support the at least one elongate support structure (e.g. filament). The at least one elongate support structure (e.g. filament) may be coiled, helical or otherwise wound. The at least one elongate support structure may be wound around the core. The at least one elongate support structure may be wound along a majority, e.g. at least 75%, or at least 90% or more of the length of the core. The at least one elongate support structure may be or comprise carbon. The at least one elongate support structure may be predominantly carbon, e.g. at least 80%, or at least 90%, at least 95% or 98% or more carbon. The at least one elongate support structure may be entirely carbon. The at least one elongate support structure may be or comprise one or more fibres. The one or more fibres may be carbon fibres. Each elongate support structure may comprise a single fibre (e.g. carbon fibre) or may comprise a plurality of fibres (e.g. carbon fibres). That is, in some examples, the elongate support structure may be or comprise a carbon fibre or be formed from a plurality of carbon fibres, and any references herein to elongate support structures or filaments may be substituted with fibres or tow, particularly carbon fibres or tow, although the disclosure is not limited to this arrangement. The combined catalyst support and heating element may comprise at least one intermediate structure between the one or more elongate support structures and the catalyst. The intermediate structure may be provided, e.g. coated, deposited or grown, directly on the at least one elongate support structure, e.g. on the one or more carbon fibres. The catalyst may be directly bonded on the intermediate structure. The fibre may be formed from the same material as the intermediate structure and / or the catalyst, and may comprise carbon. The intermediate structure may comprise an inorganic compound, crystalline and / or a covalent compound such as boron nitride, Silicon Carbide (SiC), Aluminium Nitride (AIN), Silicon Nitride (SiN), Aluminium Oxide (AI2O3) or the like. The intermediate structure and / or the catalyst may be formed in-situ in the reaction vessel, e.g. by using the one or more elongate support structures (e.g. the bare carbon fibre filaments or carbon fibre filaments with the catalyst disposed thereon) as Joule heating elements to provide heat to form the intermediate structure on the at least one elongate support structures. For example, a carbon based compound such as carbon black or the like can be provided as a reactant and subjected to Joule heating by the at least one elongate support structure in order to form carbon nanostructures such as carbon nanotubes, fullerenes, nanospheres or buckyballs on the at least one elongate support structure in situ in the reaction vessel. In another example, boron and nitrogen are provided as reactants and subjected to Joule heating by the elongate support structures in order to coat the elongate support structures with boron nitride as an intermediate structure in situ in the reaction vessel. The intermediate structure may be or comprise carbon nanotubes. The at least one elongate support structures may comprise carbon nanotubes disposed on the one or more carbon fibres, e.g. on the surface of the one or more carbon filaments. The catalyst may comprise carbon nanostructures, such as carbon nanotubes or other fullerenes and / or may comprise surface patterning on the elongate support structure. The carbon nanotubes may be elongate and may extend generally away from the surface of the one or more carbon fibres, e.g. a long axis of the carbon nanostructure may be perpendicular or oblique to the surface plane of the carbon fibre from which it extends. The intermediate structure may comprise an inorganic compound, such as Boron Nitride. The intermediate structure, e.g. the boron nitride, may be directly coated onto the carbon based heating elongate support structure, e.g. onto the one or more carbon fibres. The catalyst may be disposed, e.g. directly disposed, on an outer surface of the combined catalyst support and heating element, e.g. on an outer surface of the at least one carbon based elongate support structureor onto the intermediate structure. The catalyst may be disposed, e.g. directly disposed, on an outer surface of the at least one carbon based elongate support structureor of the intermediate structure. For example, the catalyst may be directly disposed on an outer surface of the one or more carbon fibre of the at least one carbon based heating elongate support structureor may be indirectly disposed on the one or more carbon fibre of the at least one carbon based elongate support structurewith the carbon nanotubes or other intermediate structure disposed therebetween. The catalyst may be or comprise a metallic catalyst, such as nickel, iron or ruthenium. The catalyst may be supported, e.g. directly disposed, on carbon nanotubes, which in turn may be supported, e.g. directly disposed, on the one or more carbon fibres of the at least one carbon based elongate support structure. The reaction vessel may be an elongate reaction vessel. The reaction vessel may comprise at least one inlet, which may be for receiving at least one reactant of the reaction therethough into the interior of the reaction vessel. The reaction vessel may comprise at least one outlet, which may be for allowing at least one product of the reaction to leave the interior of the reaction vessel. The at least one inlet may be provided at one end of the interior of the reaction vessel. The at least one outlet may be provided at a different end of the interior of the reaction vessel. The combined catalyst support, the heating element and optionally the core, may extend along a majority, e.g. at least 75% or 90% or more of the reaction vessel, e.g. of the length of the reaction vessel, which may be a distance between the at least one inlet and the at least one outlet. A helical axis of the combined catalyst support and heating element (e.g. of the at least one filament) may extend along the length or long dimension of the reaction vessel, e.g. generally in parallel with the long direction of the reaction vessel. The reactants may be configured to flow or otherwise travel through an area between the core and an interior surface of the reaction vessel. The reaction vessel may be configured such that the reactants flow through the reaction vessel generally along the length long direction of the reaction vessel. The reaction vessel may be provided with thermal insulation, e.g. on at least part of an outer side thereof. The electrical connectors may be metallic, e.g. copper or gold, connectors. The electrical connectors may be both electrically and thermally conductive. The electrical connectors may be elongate electrical connectors. The chemical reactor may comprise thermal storage, e.g. for storing excess heat such as excess heat from the inside of the reaction vessel and / or from the Joule heating performed using the combined catalyst support and heating element. At least one, some or all of the electrical connectors may be configured to supply heat from the reaction vessel to thermal storage. At least one or each of the electrical connectors may be provided in a thermal conduction path from the interior of the reaction vessel to the thermal storage. At least one, some or all of the electrical connectors may extend into at least one thermal storage. The electrical connectors may extend from the reaction vessel. The at least one elongate support structure may extend out of the interior of the at least one reaction vessel, and optionally the electrical connectors may connect to the at least one elongate support structure at a location outwith the interior of the reaction vessel. The at least one thermal storage may comprise a plurality of thermal storage, which may be provided at least at longitudinally opposite ends of the reaction vessel. Respective electrical connectors, e.g. connected to respective ends of the at least one elongate support structure, may extend into respective thermal storage of the plurality of thermal storage, which may be provided at respective opposite ends of the reaction vessel. At least 25% and preferably a majority, or 75% or more of a length of the electrical connectors may be provided within the thermal storage. The thermal storage may comprise a thermal storage material that may be at least partly encased in a thermally insulating material. The thermal storage material may be configured for storing heat provided via the electrical connectors. The thermal storage may be configured to supply heat to the interior of the reaction vessel, e.g. via the electrical connectors. That is, the thermal storage may be configured to store heat when there is an excess of heat in the interior of the reaction vessel, and to provide heat to the reaction vessel when the reaction vessel is under a target heat and / or below a heat of the thermal storage material. The thermal storage may comprise a phase change or non-phase change material, i.e. the storage of heat by the thermal storage may be associated with a phase change in the thermal storage material or may not be associated with a phase change in the thermal storage material, depending on the particular application. That is, the phase change material may undergo a phase change during operation of the thermal storage, e.g. to store or recover heat. The phase-change may be a solid-liquid phase change or a liquid-gas phase change. The phase change material may be or comprise a liquid-gas organic phase change material. The thermal storage may comprise a sensible heat storage system, e.g. a system in which the thermal storage material simply increases or decreases in temperature. The thermal storage may comprise a latent heat storage system, e.g. associated with a phase change in the material of the thermal storage. The thermal storage material may comprise a fluid such as water or salt solution or the like. The thermal storage material may comprise a refrigerant, such as hydrocarbons, e.g. propane or isobutene, ammonia, halogentated hydrocarbons such as tetrafluoropropene, tetrafluoroethane, pentafluoroethane or difluoromethane, carbon dioxide, or the like. The thermal storage material may comprise a metal, metal salt or silicon based material, or a mixture such as aluminium, silicon, eutectic aluminium / silicon such as ALSii2, which may be molten over at least part of a thermal cycle during operation of the thermal storage. The thermal storage material may comprise an oil, such as a synthetic or natural oil. The thermal storage material may comprise a ceramic, cement or concrete. The material of the thermal storage may comprise a polymer, gel, or wax. By providing a chemical reactor having the above features, electricity from renewable or other green sources can be used to efficiently provide heat for the reaction. A range of different catalytic supports may be provided to suit different catalysts and / or reactions. For example, catalysts can be deposited directly on the carbon elongate support structure (e.g. on carbon fibre or filament), or the carbon elongate support structure (e.g. carbon fibre or filament) can be coated or otherwise provided with intermediate structure such as carbon nanotubes or boron nitride, or other inorganic compounds on which the catalyst is bonded or attached. The chemical reactor can be used for multiple functions, e.g. fuel reactor and / or nanomaterial growth. The chemical reactor can be made compact and is highly energy efficient, with a reduced heat transfer length. It also lowers the likelihood of catalyst sintering and is resistant to hydrogen embrittlement. In addition, the use of carbon filaments (which may be or comprise carbon fibres) rather than bulk supports facilitates better product harvesting and improves reaction efficiency. According to a second example of the present disclosure is a system comprising at least one, e.g. a plurality of, electrically heated chemical reactors. Optionally, each electrically heated reactor may be or comprise an electrically heated chemical reactor of the first example. Each of the electrically heated chemical reactors may comprise a reaction vessel and at least one electrical heating element for heating an interior of the reaction vessel and / or reactants of a chemical reaction performed in the reaction vessel. The at least one electrical heating element may be or comprise the at least one elongate support structure of the first example. Each of the electrically heated chemical reactors may comprise at least one, e.g. at least a pair, of electrical connectors, which may be thermally and electrically conductive electrical connectors, such as metallic, e.g. copper or gold, electrical connectors. The electrical connectors may be elongate electrical connectors. The electrical connectors may be the electrical connectors described in relation to the first example. The electrical connectors may provide electrical connections to the at least one electrical heating element. The electrical connectors may be configured to electrically connect to the at least one electrical heating element so that an electrical current can be provided between electrical connectors of at least a pair of the electrical connectors via the at least one electrical heating element. The at least one electrical heating elements may comprise Joule heating elements. The electrical element may be or comprise the at least one elongate support structureof the first example, e.g. at least one carbon filament, such as at least one carbon fibre based filament. The system may comprise thermal storage. At least one or each of the electrical connectors may be configured to provide heat from the reaction vessel to the thermal storage. At least one or each of the electrical connectors may be provided in a thermal conduction path from the interior of the reaction vessel to the thermal storage. Part of at least one or each of the electrical connectors may extend into the thermal storage. At least 25% and preferably a majority, or 75% or more of a length of the electrical connectors may be provided within the thermal storage. The thermal storage may be shared between different electrically heated chemical reactors. That is at least one or each electrical connector of at least one of the plurality of electrically heated chemical reactors may extend into the same thermal storage as at least one electrical connector of at least one other of the plurality of electrically heated chemical reactors. By sharing thermal storage between different chemical reactors, then the overall volume of the system may be reduced and / or the thermal storage may be more efficient in use. The thermal storage may comprise a phase change or non-phase change material, i.e. the storage of heat by the thermal storage may be associated with a phase change in the material of the thermal storage or may not be associated with a phase change in the thermal storage, depending on the particular application. The phase change material may be configured to change phase during heat storage. The phase change material may be configured to change phase from a solid to a liquid and / or from a liquid to a gas during operation of the system, e.g. during heat storage. The phase change material may be or comprise a liquid-gas organic phase change material. The thermal storage may comprise a sensible heat storage system, e.g. a system in which the material of the thermal storage simply increases or decreases in temperature. The thermal storage may comprise a latent heat storage system, e.g. associated with a phase change in the material of the thermal storage. The material of the thermal storage may comprise a fluid such as water or salt solution or the like. The material of the thermal storage may comprise a refrigerant, such as hydrocarbons, e.g. propane or isobutene, ammonia, halogentated hydrocarbons such as tetrafluoropropene, tetrafluoroethane, pentafluoroethane or difluoromethane, carbon dioxide, or the like. The material of the thermal storage may comprise a metal, metal salt or silicon based material, or a mixture such as aluminium, silicon, eutectic aluminium / silicon such as ALSii2, which may be molten over at least part of a thermal cycle during operation of the thermal storage. The material of the thermal storage may comprise an oil, such as a synthetic or natural oil. The material of the thermal storage may comprise cement or concrete. The material of the thermal storage may comprise a polymer, gel, or wax. The thermal insulation of the reaction vessel of at least one chemical reactor of the plurality of chemical reactors may be shared with the reaction vessel of at least one other chemical reactor of the plurality of chemical reactors. The thermal insulation of the reaction vessel of at least one chemical reactor of the plurality of chemical reactors may be provided between or around both of the reaction vessel of the at least one chemical reactor of the plurality of chemical reactors and the reaction vessel of at least one other chemical reactor of the plurality of chemical reactors. According to a third example of the present disclosure is a method of manufacturing or repairing the electrically heated chemical reactor of the first example, the method comprising providing a reaction vessel, and installing a combined catalyst support and heating element that comprises a catalyst supported by the combined catalyst support and heating element, wherein the combined catalyst support and heating element comprises at least one carbon based elongate support structure. The elongate support structure may be or comprise a filament that is a carbon based filament, a carbon tow, carbon fibre, carbon rod, e.g. a graphite rod, or the like. The method may comprise connecting the at least one elongate support structureto at least a pair of electrical connectors. The method may comprise providing at least one thermal storage and providing at least part of at least one or each of the electrical connectors in the thermal storage. The method may comprise providing thermal insulation around at least part of the reaction vessel. According to a fourth example of the present disclosure is a method of manufacturing a combined catalyst support and heating element, the method comprising at least the steps of: providing at least one elongate support structurethat is an electrically and thermally conductive carbon based elongate support structure, providing a catalyst on the elongate support structure. The at least one elongate support structuremay be electrically resistive and configured for Joule heating. The combined catalyst support and heating element may comprise any features or properties described above in relation to the combined catalyst support and heating element of the first example. The at least one elongate support structure may be or comprise one or more carbon based filaments, fibres, tow, rod such as a graphite rod, or the like. The at least one elongate support structure may be or comprise carbon. The at least one elongate support structure may be predominantly carbon, e.g. at least 80%, or at least 90%, at least 95% or 98% or more carbon. The at least one elongate support structure may be entirely carbon. The at least one elongate support structure may comprise one or more fibres. The one or more fibres may be carbon fibres. That is, the at least one elongate support structure may comprise one or more fibres, such as carbon fibres. The method may comprise providing at least one intermediate structure onto the at least one elongate support structure (e.g. onto bare carbon fibre filaments or carbon fibre filaments with the catalyst disposed thereon) in situ, i.e. in the reaction vessel in which the at least one elongate support structure is to be used as a combined catalyst support and heating element, and may comprise using the one or more elongate support structures (e.g. the bare carbon fibre filaments or carbon fibre filaments with the catalyst disposed thereon) as Joule heating elements in order to form the intermediate structure on the at least one elongate support structure. For example, a carbon based compound such as carbon black or the like can be provided as a reactant and subjected to Joule heating by the one or more elongate support structure in order to form carbon nanostructures such as carbon nanotubes on the at least one elongate support structure in situ in the reaction vessel in which the combined catalyst support and heating element is to be used. In another example, boron and nitrogen are provided as reactants and subjected to Joule heating by the one or more elongate support structures in order to coat the one or more elongate support structures with boron nitride as an intermediate structure in situ in the reaction vessel. The method may comprise providing at least one intermediate structure between the at least one elongate support structure (e.g. the one or more fibres) and the catalyst. The method may comprise directly attaching the catalyst to the intermediate structure. The at least one elongate support structure may comprise carbon nanotubes. The intermediate structure may be or comprise carbon nanotubes. The at least one elongate support structure may comprise carbon nanotubes disposed on the one or more carbon fibres, e.g. on the surface of the one or more carbon fibres. The carbon nanotubes may be elongate and method may comprise providing the carbon nanotubes so that they extend generally away from the surface of the one or more carbon fibres. The intermediate structure may comprise an inorganic compound, such as Boron Nitride. The method may comprise coating, e.g. directly coating, the intermediate structure, e.g. the boron nitride onto the carbon based elongate support structure, e.g. onto the one or more carbon fibres or other filaments. The method may comprise disposing the catalyst, e.g. disposing the catalyst directly, on an outer surface of the combined catalyst support and heating element, e.g. on an outer surface of the at least one carbon based elongate support structure or onto the intermediate structure. The method may comprise disposing, e.g. directly disposing, the catalyst on an outer surface of the at least one carbon based elongate support structure or of the intermediate structure. For example, the catalyst may be directly disposed on an outer surface of the one or more carbon fibre of the at least one carbon based heating elongate support structure or may be indirectly disposed on the one or more carbon fibre of the at least one carbon based elongate support structure with the carbon nanotubes or other intermediate structure disposed therebetween. The catalyst may be or comprise a metallic catalyst, such as nickel, iron or ruthenium. The catalyst may be supported, e.g. directly disposed, on carbon nanotubes, which in turn may be supported, e.g. directly disposed, on the one or more carbon fibres or other filaments of the at least one carbon based elongate support structure. The combined catalyst support and heating element may subsequently be used to provide heating and / or catalysis in a different chemical reaction to that used to provide the intermediate layer and / or catalyst on the elongate support structure. According to a fifth example of the present disclosure is a method of performing a chemical reaction using the chemical reactor of the first example or the system of the second example. The method may comprise providing at least one reactant. The method may comprise providing an electrical current through the at least one elongate support structure of the first example or the heating element of the second example so as to generate heat in the at least one elongate support structure of heating element to heat the at least one reactant. The method may comprise heating the at least one reactant by Joule heating from the at least one elongate support structure or heating element. The heating may be performed in the presence of a catalyst provided on the at least one elongate support structure or heating element. The chemical reaction may comprise production of carbon nanostructures, such as carbon nanotubes, nanospheres, or the like. The at least one reactant may comprise carbonaceous material such as carbon black, graphite, or the like. The chemical reaction may comprise reforming of a hydrocarbon, such as an alkane, or an alcohol, such as reforming of methane or methanol. The reforming may comprise steam reforming. The chemical reaction may comprise pyrolysis of a hydrocarbon, e.g. alkane pyrolysis, such as methane pyrolysis. The chemical reaction may comprise hydrogen production, 11), as these seek to define the core concepts of the invention in short, simple statements, e.g. pyrolysis for producing hydrogen. The chemical reaction may comprise pyrolysis of an alkane, such as methane, for producing hydrogen. The chemical reaction may comprise ammonia cracking, e.g. for hydrogen production. The chemical reaction may comprise ammonia synthesis, e.g. for hydrogen storage. The chemical reaction may comprise ammonia reforming, e.g. for the production of hydrogen and / or hydrogen cyanide. The chemical reaction may comprise any combination of the above, e.g. production of carbon nanostructures with one of: pyrolysis or cracking to produce hydrogen, ammonia synthesis and / or ammonia reforming. The individual features and / or combinations of features defined above in accordance with any example of the present invention or below in relation to any specific embodiment of the invention may be utilised, either separately and individually, alone or in combination with any other defined feature, in any other example or embodiment of the invention. Furthermore, the present invention is intended to cover apparatus configured to perform any feature described herein in relation to a method and / or a method of using or producing, using or manufacturing any apparatus feature described herein. Description of the Drawings For a better understanding of the present disclosure and to show how embodiments may be put into effect, reference is made to the accompanying drawings in which: Figure 1 is a schematic of a chemical reactor; Figure 2 is a schematic of a system comprising a plurality of the chemical reactors of Figure 1; Figure 3 is a schematic representation of part of a carbon based filament supporting a catalyst for use in a chemical reactor, such as that of Figure 1; Figure 4 is a schematic representation of part of an alternative carbon based filament supporting a catalyst for use in a chemical reactor, such as that of Figure 1; Figure 5 is a schematic representation of part of a different carbon based filament whose surface is configured as a catalyst for use in a chemical reactor, such as that of Figure 1; Figure 6 is a schematic representation of part of a further carbon based filament supporting a catalyst for use in a chemical reactor, such as that of Figure 1; Figure 7 is a schematic showing examples of different filaments for use in a chemical reactor, such as that of Figure 1, for different chemical reactions. Figure 8 is a schematic of a process for producing “green” ammonia as a material for storage and transport of hydrogen using a chemical reactor, such as that of Figure 1 Figure 9 is a method of producing a catalyst supported on a combined catalyst support and heating element for use in a chemical reactor, such as that of Figure 1; Figure 10 is a method of manufacturing the chemical reactor of Figure 1; and Figure 11 is a method of performing a chemical reaction using the chemical reactor of Figure 1 and / or the system of Figure 2. DETAILED DESCRIPTION In the following detailed description, reference is made to the accompanying drawings that form a part hereof and, in which is shown by way of illustration, specific embodiments in which the inventive subject matter may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice them, and it is to be understood that other embodiments may be utilized, and that structural, logical, and electrical changes may be made without departing from the scope of the inventive subject matter. Such embodiments of the inventive subject matter may be referred to, individually and / or collectively, herein by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept if more than one is in fact disclosed. The following description is, therefore, not to be taken in a limited sense, and the scope of the inventive subject matter is defined by the appended claims and their equivalents. In the following embodiments, like components are labelled with like reference numerals. As used herein, except wherein the context requires otherwise, the terms “comprises”, “includes”, “has” and grammatical variants of these terms, are not intended to be exhaustive. They are intended to allow for the possibility of further additives, components, integers or steps. Specific embodiments will now be described with reference to the drawings. Figure 1 illustrates one example of an electrically heated chemical reactor 5 comprising: a reaction vessel 10; a combined catalyst support and heating element 15; and a catalyst 20 supported by the combined catalyst support and heating element 15. The combined catalyst support and heating element 15 comprises at least one elongate support structure, in this example in the form a plurality of filaments 25 that are carbon based filaments. In examples, each filament is formed of one or more carbon fibres or carbon tow. In other examples, a carbon rod, such as a graphite rod, could be used instead of the filaments 25. In preferred embodiments, such as that shown in Figures 1, the combined catalyst support and heating element 15 comprises multiple filaments 25 that are preferably electrically connected in parallel. The reaction vessel 10 is an elongate cylindrical vessel comprising a reactant inlet 30 towards one end of the reaction vessel 10 and a product outlet towards an opposite end of the reaction vessel 10 along a longitudinal direction of the reaction vessel 10. The reactant inlet 30 is configured to receive reactants therethrough and into an interior of the reaction vessel 10 and the product outlet 35 is configured for extraction of product from the interior of the reaction vessel therethrough. This arrangement is particularly suited to continuous processing but the present disclosure is not limited to this, and could be straightforwardly adapted for batch processing. Although a specific arrangement of reactant inlet 30 and product outlet 35 is shown and described, the present disclosure is not limited to this and one or both of the reactant inlet 30 and product outlet 35 need not be present (e.g. in the case of batch processing), or may be provided at different locations, or different numbers of reactant inlet 30 and / or product outlet 35 may be provided, amongst other possibilities. The reaction vessel 10 is configured for performing chemical processing at elevated temperatures, with heat being mainly or entirely provided by the combined catalyst support and heating element 15. The combined catalyst support and heating element 15 comprises at least one, and preferably a plurality of, the filaments 25 that each are, or comprise, one or more carbon fibres. The filaments 25 have a high aspect ratio, e.g. a length of at least an order of magnitude or two, three, four, five, six or higher orders of magnitude more than the diameter of the filament. The filaments 25 are also flexible, and the motion of the filaments 25 during operation of the chemical reactor 5 helps shed product from the filament 25. The filaments 25 are would in a helical shape around a central core 40. The core 40 helps to distribute heat, and has sufficient structural integrity to support the combined catalyst support and heating element 15. The core 40 is thermally conductive. In this example, the core 40 is a stainless steel core coated with a ceramic coating or core cover, but other materials could be used, e.g. the core could be formed entirely from ceramic, another metal, or other suitable material. The core 40 in this example is an elongate solid cylindrical core, but other form factors could be used. The core 40 in this example extends through the interior of the reaction vessel 10 such that the long direction of the longitudinal core 40 is aligned with that of the longitudinal reaction vessel 10. An annulus 42 is provided between the core 40 and an interior wall of the reaction vessel 10, which is optionally sealed at each end. The annulus 42 is in fluid communication with the reactant inlet 30 and reactant outlet 35, when present, so that reactants and / or product can pass along the annulus 42, e.g. from the reactant inlet 30 to the product outlet 35. The one or more filaments 25 are provided in the annulus 42 to provide heat and catalysis to the reactants in order to perform the chemical reaction. One or more, preferably a plurality of temperature sensors 43, such as thermocouples, are provided inside the reaction chamber, preferably at spaced apart locations along a long direction of the reaction chamber, e.g. at the inlet, the outlet and / or centre of the reaction chamber. In this way, the electricity supplied to the filaments 25 can be controlled in order to control the heat output by the combined catalyst support and heating element 15, and thereby the temperature of the reaction. The filaments 25 are connected at each end to a respective electrical connector 45, 50. The electrical connectors 45, 50 are generally metallic, e.g. copper or gold, and are electrically conductive. The electrical connectors 45, 50 are provided or providable in an electrical circuit with an electrical source 52, preferably comprising renewable electricity, e.g. by being connected to solar, wind, or tidal energy or the like, preferably with the electrical source being on site with the chemical reactor 5. The at least one filament 25 is thermally conductive and also electrically conductive to an extent, but is electrically resistive so that passage of current through the at least one filament 25 between the electrical connectors 45, 50 at each end thereof results in Joule heating. This Joule heating from the at least one filament 25 is used to provide at least some, a majority or all of the heat required to perform the chemical reaction. Beneficially, the heat is concentrated at and around the catalysis sites, as the catalyst 20 is provided on the combined catalyst support and heating element 15, e.g. by being provided directly or indirectly on the one or more carbon fibres that form the majority of the at least one filament 25. In the example of Figure 1, the at least one carbon based filament 15 comprises one or more carbon fibres 55 that are provided with intermediate structure 60, in this example, in the form of carbon nanotubes, on its surface, e.g. by coating, deposition, growth (e.g. in-situ growth) or otherwise. In this example, the carbon nanotubes are elongate and provided so that they generally extend away from the surface of the carbon fibre 55 so that their long axis is oblique or perpendicular to that of the carbon fibre 55. The catalyst 20 is provided on the intermediate structure 60, e.g. on distal ends of the carbon nanotubes, so as to be spaced from the carbon fibre 55 by the intermediate structure 60. The intermediate structure 60 is preferably thermally conductive so that heat can be transferred from the carbon fibre 55, where most of the Joule heating occurs, to the catalyst 20 via the thermally conductive intermediate structure 60. Although the above structure of combined catalyst support and heating element 15 can be particularly beneficial, the present disclosure is not limited to this and other suitable arrangements of combined catalyst support and heating element 15 could be used, such as but not limited to those described in relation to Figures 3 to 7. As discussed in relation to Figure 7, different arrangements of combined catalyst support and heating element 15 can be better suited to different applications I reactions. The catalyst 20 in some examples is or comprise a metallic catalyst, such as nickel, iron or ruthenium, but is not limited to these and could be any other suitable catalyst depending on the proposed application, such as platinum, palladium, zinc, or the like. In some examples the fibre 55 of the filament 25 is of the same material as the intermediate layer 60 (also called the intermediate structure) and / or the catalyst 60. For example, the fibre 55 could be carbon fibre and one of the intermediate structure or the catalyst could also comprise carbon, e.g. carbon nanostructures, such as carbon nanotubes or nanospheres, surface patterning on the surface of the carbon fibre, activated carbon, or the like. Although not shown, the reaction vessel 10 can be provided with thermal insulation along at least part of an outer surface thereof, particularly along longitudinally extending walls thereof. Figure 2 shows a chemical reaction system 100 that comprises a plurality of chemical reactors 5’. Features of Figure 2 that are equivalent to features of Figure 1 but not identical are provided with the same reference numeral as those of Figure 1 but appended with an apostrophe. However, most of the features of the chemical reactors 5’ are the same as those of the chemical reactors 5 of Figure 1. That is, each chemical reactor 5’ of the plurality of chemical reactors 5’ is substantially the same as the chemical reactor 5 of Figure 1 other than the electrical connectors 45, 50’ are extended so as to be elongate and to extend out of and away from the reaction vessels 10 of the respective chemical reactor 5’. This may be achieved by simply providing overlong elongate connectors 45’, 50’ or by physically connecting metallic or other conductive extensions to the connectors 45, 50. The plurality of chemical reactors 5’ are arranged in parallel. Thermal storage 105, 110 that forms a thermal battery is provided at either end of the chemical reactors 5’. Preferable the thermal storage 115, 110 comprises a thermal storage material that is a phase change material, such as a liquid-gas organic phase change material, which has been found to be particularly effective. In examples, the thermal storage material is contained within a thermally insulating container. Although two sets of thermal storage 110, 115 are shown in Figure 2, the present disclosure is not limited to this and only a single thermal storage 115 could be used or different numbers of thermal storage. The thermal storage need not be phase change thermal storage and other forms of thermal storage material s could be used. The electrical connectors 45’, 50’ (or the extensions thereof) of each reactor 5’ extend out of the respective reaction vessel 10 and into the thermal storage 105, 110 (i.e. into or adjacent the thermal storage material) at the relevant end of the reaction vessel 10. In this example, a majority of the length of the electrical connectors 45’, 50’ (or the extensions thereof) of each reactor 5’ is provided within the thermal storage 105, 110 for more efficient heat transfer to / from the thermal storage 110, 115. With the arrangement above, excess heat from the chemical reactors 5’ can be transferred to the thermal storage and reused, e.g. to provide heat later in the reaction process or to an external source. This further enhances the overall efficiency (total energy in vs total energy out, including electrical and thermal energy). As such, heat can flow in different directions between the thermal storage 110, 115 and the interior of the reaction vessel 10 at different stages of operations of the chemical reactor(s) 5’ depending on the current need for heating, cooling or maintaining the heat of the interior of the reaction vessels 10. Although a modification 5’ of the chemical reactor 5 of Figure 1 is used in the system 100 of Figure 2, that need not be the case, and other chemical reactors could be used, such as chemical reactors that don’t have a combined catalyst support and heating element. The only key requirement is that the electrical connectors or electrodes that are used to provide electrical supply for electrical heating in the chemical reactor (or extension thereof) extend out from the reaction vessel and into the thermal storage 105, 110. Figures 3 to 6 show various examples of filament that could be used as the combined catalyst support and heating element in the chemical reactor 5 of Figure 1 (or in the chemical reactors 5’ in the example of Figure 2). Figure 3 shows an example in which catalyst 20 is deposed directly onto the surface of one or more elongate carbon fibres 55 in order to form the filament 25. Figure 4 shows an example in which the at least one carbon fibre 55 of the at least one filament 15 is provided with intermediate structure 60 in the form of carbon nanostructures, e.g. carbon nanotubes, on its surface, e.g. by coating, deposition, growth (e.g. in-situ growth) or otherwise. The carbon nanotubes are elongate and provided so that they generally extend away from the surface of the carbon fibre 55 so that their long axis is oblique or perpendicular to that of the carbon fibre 55. The catalyst 20 is provided on the intermediate structure 60, e.g. on distal ends of the carbon nanotubes, so as to be spaced from the carbon fibre 55 by the intermediate structure 60. However, the carbon nanotubes that form the intermediate structure 60 provides a good thermal conduction path from the carbon fibre 55 to the catalyst 20. Figure 5 shows an example in which the surface of the carbon fibres 55 have been micro-patterned and the micro-patterned surface of the carbon fibre acts as the catalyst 20. The surface can take any suitable patterned form, which may comprise any or, or any combination of, channels, hollows, projections, ridges and / or the like. For example, the surface of the carbon fibre 55 could be patterned with triangular projections as shown, or discrete notches in the surface of the carbon fibre, or with trapezium or trapezoidal shaped protrusions or ridges, or with semi-circular or hemispherical channels or hollows, or square shaped channels or hollows, or the like. The surface of the carbon fibres could comprise activated carbon in some examples. In a variation of Figure 5, the surface of the carbon fibre 55 can be provided with carbon nanostructures such as carbon nanotubes, e.g. by chemical vapour deposition or any other suitable technique, and the carbon nanostructures may operate as catalysts. In these examples, the carbon nanostructures, e.g. nanotubes, may extend away from the surface of the carbon fibre, such that a long direction of the carbon nanostructures is oblique or perpendicular to a surface plane of the carbon fibre. As such, in these examples, carbon acts as all of the support, heating element and the catalyst. Figure 6 shows another example in which at least part of the surface of the carbon fibre is coated with a ceramic or covalent coating as the intermediate structure 60’, and the catalyst 20 is provided on the ceramic covalent coating. Examples of suitable covalent coatings include Boron Nitride (BN), Silicon Carbide (SiC), Aluminium Nitride (AIN), Silicon Nitride (SiN), Aluminium Oxide (AI2O3). The disclosure of the present application is not limited to the above forms of filament, and other forms could be used. Different forms of filament can be more beneficial for different reactions. Some examples of these are shown in Figure 7. For example, all four of the forms of filament shown in Figures 3 to 6 can be usefully used in pyrolysis (e.g. of methane or other alkane or hydrocarbon) in order to produce hydrogen. The filament shown in Figure 6 has been found to be particularly beneficial in steam reforming of hydrocarbons such as alkanes and alcohols, such as methane and methanol. The filaments shown in Figures 3, 4 and 6 have also been found to be particularly beneficial in ammonia cracking, synthesis and reforming, e.g. cracking ammonia to produce carbon free hydrogen, synthesis of ammonia to effectively store hydrogen (as hydrogen can be readily recovered from ammonia), and reforming of ammonia to produce hydrogen and hydrogen cyanide (HCN), which is a useful industrial chemical. The chemical reactors 5, 5; described above are also useful in producing carbon nanostructures, which could be harvested as product or used to produce the combined catalyst support and heating element 15. For example, formation of the intermediate layer 60 in situ in the reaction vessel 10 is illustrated as process 705 in Figure 7. In this example, the one or more filaments 15 are installed as either bare carbon fibre 55 filaments 25 or with catalyst 20 provided directly on the surface of the carbon fibres 55 that form the filaments 25 (the latter being as shown in Figure 3), within the reaction vessel. Reactants are provided into the reaction vessel 10 and an electric current is applied to the filaments 15 in order to perform Joule heating on the reactants to form the intermediate layer 60 (also termed as the intermediate structure). For example, a carbon based reactant (such as carbon black particles or other carbonaceous material) can be provided as reactants to form carbon nanotubes on the surface of the carbon fibres 50 in situ to act as the intermediate structure 60 or the catalyst 20. If the catalyst 20 is provided then the nanotubes act as the intermediate structure 60 and support the catalyst 20 at distal ends of the nanotubes as shown in Figures 4 and 7. In another example, boron and nitrogen (or boron nitride vapour) are provided as reactants to a form boron nitride coating as the intermediate layer 60 (although other covalent, ceramic and / or inorganic materials could be used, such as but not limited to Silicon Carbide (SiC), Aluminium Nitride (AIN), Silicon Nitride (SiN), Aluminium Oxide (AI2O3)). The adapted filaments (that include the carbon nanostructures or Boron Nitride or the ceramic or other inorganic coatings formed in-situ in the reactor) are then used to provide Joule heating in other, different reactions, such as ammonia cracking, ammonia synthesis, ammonia reforming to produce hydrogen, and / or the like. Figure 8 shows a schematic of a process for producing ammonia (as an effective store of hydrogen, as hydrogen can be easily recovered from ammonia) from renewable energy. Ammonia is easier to store and transport than hydrogen, has a higher volumetric density than hydrogen, and can be converted to hydrogen gas at its destination, as required, as a cheap source of carbon-free hydrogen. In the process of Figure 8, at 805, renewable electricity is generated, e.g. by solar, wind, tidal or other renewable (or non-renewable) energy source, and used to electrolyse water or perform another electrochemical process in order to produce hydrogen. At 810, the chemical reactor 5 of Figure 1 or the system 100 of Figure 2 is used to perform a chemical reaction in which nitrogen and hydrogen from step 805 are provided as reactants, and ammonia is provided as the product is performed. In this case, the filaments 25 are preferably the filaments shown in any of Figures 3, 4 or 6 with, for example, nickel, iron, ruthenium and / or another suitable metal as the catalyst. For ammonia production, the chemical reactor 5 of Figure 1 or the system 100 of Figure 2 is configured with one or more from the group of: Iron, Nickel, Ruthenium or a combination of these metals as catalyst. The filaments 25 are used to provide, at least in part, heat to the reaction such that the reaction temperature is in a range from 200°C to 400°C and the pressure in the reaction vessel 10 is in a range from 100bar to 200bar. The reactants are provided in a molar ratio of 3:1 H2:N2. At 815, the ammonia can be stored, e.g. in tanks, and transported to its destination. At 820, the ammonia can be converted back into hydrogen, e.g. by using conventional processes or by using the chemical reactor 5 of Figure 1 or the system 100 of Figure 2. For example, hydrogen production from ammonia, the chemical reactor 5 of Figure 1 or the system 100 of Figure 2 is configured with one or more from the group of: Ruthenium, Nickel, Iron or combination of these metals as catalyst. The filaments 25 are used to provide, at least in part, heat to the reaction such that the reaction temperature is in a range between 400°C and 700°C and the pressure in the reaction vessel 10 is generally at atmospheric pressure. Ammonia is provided as the reactant. Figure 9 is a flowchart of a process of producing catalyst on a combined catalyst support and heating element 15, such as that described in relation to Figures 1, 2 or any of Figures 3 to 6. At 905 a carbon fibre filament is provided. Optionally, at 910, the intermediate layer 60 is provided on the surface of the carbon fibre. With the filament of Figure 4, the intermediate layer comprises carbon nanotubes. With the example of Figure 6, the intermediate layer comprises a covalent compound such as boron nitride, Silicon Carbide (SiC), Aluminium Nitride (AIN), Silicon Nitride (SiN), Aluminium Oxide (AI2O3), or the like. The intermediate layer could be provided by coating, deposition (e.g. chemical vapour deposition), growth (e.g. in-situ in the reactor in which it is to be used) or otherwise. In examples the carbon nanotubes can be provided as intermediate layer 60 (also called intermediate structure) or as catalyst 20 on the carbon fibres by chemical vapour deposition (CVD). In a beneficial example, the intermediate layer can be grown in-situ. That is, the chemical reactor 5 or 5’ can be set up with only carbon fibre 55 as the filament 25, either bare carbon fibre 55 or optionally with catalyst deposited on the surface of the carbon fibre 55 (as shown in Figure 3). The carbon fibre filaments 25 are used to perform Joule heating in with a carbon based reactant feedstock to produce carbon nanotubes as an intermediate layer 60, as shown in Figure 4. In another example, the carbon fibre filaments 25 are used to perform Joule heating in with nitrogen and boron based reactants feedstock to produce a boron nitride intermediate layer 60, as shown in Figure 6. At 915, the catalyst 20 is applied to the carbon fibres 55 or the intermediate layer 60 using techniques known in the art, such as coating, deposition (including chemical vapour deposition), growth (e.g. in-situ) or otherwise. Figure 10 is a flowchart of a method of manufacturing or repairing the chemical reactor 5 of Figure 1. At 1005 the reaction vessel 10 is provided. At 1010, a combined catalyst support and heating element 15 that comprises at least one filament 25 supporting a catalyst 20 is provided. The at least one filament 25 supporting the catalyst 20 could be any of those shown in Figures 3 to 6. In some examples, such as those of Figures 3, 4 and 6, the catalyst is not integral with the carbon fibre 55 or intermediate layer 60 but is provided on or fixed to the carbon fibre 55 or intermediate layer 60. In other examples, such as that of Figure 5, the catalyst may be an integral part of the carbon fibre. This step can also comprise winding the combined catalyst support and heating element 15 around the core 40, although in other examples the combined catalyst support and heating element 15 could come pre-wound around a core 40 or a core may not be used. In step 1015, opposing ends (or points on the combined catalyst support and heating element 15 proximate opposing ends) of the combined catalyst support and heating element 15 are connected to the electrical connectors 45, 50. The reaction chamber is optionally sealed (apart from the reactant inlet 30 and / or product outlet 35). Optionally, part of, which may be a majority part of, the electrical connectors are provided inside, or otherwise in thermal communication with, the thermal storage 105, 110. The electrical connectors are connectable or then connected to an electrical source. Figure 11 is a flowchart of a method of performing a chemical reaction using the chemical reactor of Figure 1 or the system of Figure 2. At 1105, the reactants are provided into the interior of the reaction vessel 10. For example, the reactant may be provided via the reactant inlet 30, e.g. as part of a continuous process, or closed into the interior of the reaction vessel in a batch process, for example. At 1110 heat is provided to the reactants by applying electrical current through the one or more filaments 15 such that the resistance of the elements causes Joule heating of the filaments 15 and thereby the catalyst 20 and reactants in order to perform the chemical process. In examples, the reactants could include nitrogen and hydrogen to produce ammonia (with suitable catalysts include nickel, iron, ruthenium or the like). Ammonia synthesis can be performed at a temperature T in a range 300<t<500°C. The reverse reaction (Ammonia decomposition into hydrogen and nitrogen) can also be performed with similar physical set up but higher temperatures T in a range 500<T<600°C. Another reaction that can be performed is methane pyrolysis, which can be carried out at temperatures greater than 800°C. Although specific examples are described above, it will be appreciated that 5 variations may be made therein, within the scope of the claims that define the invention.

Claims

1. An electrically heated chemical reactor comprising: a reaction vessel; a combined catalyst support and heating element; and a catalyst supported by the combined catalyst support and heating element; wherein the combined catalyst support and heating element comprises at least one carbon based elongate support structure.

2. The electrically heated chemical reactor of claim 1, wherein the at least one elongate support structure is configured to provide Joule heating for heating the reaction vessel or reactants that are provided or to be provided therein, and the at least one elongate support structure also supports the catalyst.

3. The electrically heated chemical reactor of any preceding claim, wherein:the elongate support structure is an electrically conductive but electrically resistive element;connected to at least a pair of electrical connectors; andconfigured to conduct electricity from at least one of the electrical connectors to at least one other of the electrical connectors in order to provide the heat.

4. The electrically heated chemical reactor of any preceding claim, wherein the at least one elongate support structure is or comprises at least one carbon based filament, at least one carbon fibre or a carbon rod.

5. The electrically heated chemical reactor of any preceding claim, wherein the at least one elongate support structure is an elongate filament, which has a high aspect ratio comprising a length of at least an order of magnitude more than the diameter of the filament.

6. The electrically heated chemical reactor of any preceding claim, wherein the at least one elongate support structure is a flexible elongate support structure.

7. The electrically heated chemical reactor of any preceding claim, further comprising an elongate, thermally conductive core within the reaction vessel and the at least one elongate support structure is a wound filament that is wound around the core.

8. The electrically heated chemical reactor of any preceding claim, wherein the at least one elongate support structure is carbon or is predominantly carbon.

9. The electrically heated chemical reactor of claim 8, wherein each elongate support structure of the at least one elongate support structure is or comprises carbon fibre.

10. The electrically heated chemical reactor of any preceding claim, wherein the combined catalyst support and heating element comprises at least one intermediate structure between the one or more elongate support structure and the catalyst.

11. The electrically heated chemical reactor of claim 10, wherein the intermediate structure comprises carbon nanostructures and / or boron nitride.

12. The electrically heated chemical reactor of any preceding claim, wherein the catalyst is a metallic catalyst.

13. The electrically heated chemical reactor of claim 3 or any claim dependent thereon, further comprising thermal storage, and wherein the electrical connectors are both electrically and thermally conductive and are elongate, and at least one or all of the electrical connectors extends from the reaction vessel into the thermal storage and / or the electrical connectors are provided in a thermal pathway from the interior of the reaction vessel to the thermal storage.

14. A system comprising a plurality of electrically heated chemical reactors according to any of the preceding claims, wherein the system comprises thermal storage and at least one of the electrically heated chemical reactors comprises at least a pair of elongate electrical connectors that are thermally and electrically conductive; and part of at least one or each of the electrical connectors extends into the thermal storage and / or at least one or each of the electrical connectors are provided in a thermal pathway from the interior of the reaction vessel to the thermal storage.

15. The system of claim 14, wherein the thermal storage is shared between different electrically heated chemical reactors, and at least one electrical connector of at least one of the plurality of electrically heated chemical reactors extends into, or is part of a same thermal pathway to, the same thermal storage as at least one electrical connector of at least one other of the plurality of electrically heated chemical reactors.

16. The system of claim 14 or 15, wherein the thermal storage comprises a phase change thermal storage material that is configured to change phase during heat storage, in use.

17. A method of manufacturing or repairing the electrically heated chemical reactor of any of claims 1 to 13, the method comprising providing a reaction vessel, and installing a combined catalyst support and heating element and supporting a catalyst by the combined catalyst support and heating element, wherein the combined catalyst support and heating element comprises at least one carbon based elongate support structure.

18. A method of manufacturing a combined catalyst support and heating element, the method comprising at least the steps of: providing at least one elongate support structure that is an electrically and thermally conductive carbon based elongate support structure; and providing a catalyst on the elongate support structure.

19. The method of claim 18, wherein the method further comprises providing the catalyst and / or at least one intermediate structure onto the at least one elongate support structure in situ in a reaction vessel in which the combined catalyst support and heating element is to be subsequently used, and using the one or more elongate support structures as Joule heating elements in order to form or otherwise provide the intermediate structure and / or the catalyst on the at least one elongate support structure.

20. The method of claim 19, wherein the intermediate structure comprises carbon nanostructures and / or Boron Nitride.

21. A method of performing a chemical reaction using the chemical reactor of any of claims 1 to 12 or the system of any of claims 13 to 16, the method comprising:providing at least one reactant;providing an electrical current through the at least one elongate support structure of the chemical reactor so as to generate heat in the at least one elongate support structure to heat the at least one reactant by Joule heating from the at least one elongate support structure, the heating being performed in the presence of a catalyst provided on the at least one elongate support structure.

22. The method of claim 21, wherein the method is a method of producing carbon nanostructures, and the at least one reactant comprises a carbonaceous material.

23. The method of claim 21, wherein the method is a method of one of: reforming of 5 a hydrocarbon or an alcohol; pyrolysis of a hydrocarbon; hydrogen production from pyrolysis of an alkane as a reactant, ammonia cracking or reforming with ammonia as a reactant, or otherwise; and / or ammonia synthesis.

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