Cyanide on Demand

Abstract

A reactor and method are provided for reacting a feed gas consisting of an alkane, such as methane, and ammonia to hydrogen cyanide and / or nitriles, where heat for the endothermic reaction is provided by resistive heating. Specifically, the reaction is the BMA (hydrogen cyanide from methane and ammonia) reaction.

Description

[Technical field]

[0001] Technical Field The present invention provides a reactor and process for carrying out the BMA (Blausaeure aus Methan und Ammoniak; also known as the Degussa process) reaction and / or nitrile synthesis, which converts a feed gas containing an alkane such as methane and ammonia into hydrogen cyanide and / or nitriles, characterized in that heat for the endothermic BMA reaction is provided by resistive heating. [Background technology]

[0002] background Hydrogen cyanide is used in the chemical industry to produce intermediate chemicals such as acrylonitrile, methyl methacrylate, and adiponitrile. However, hydrogen cyanide (HCN) is difficult to produce and often requires chemical reactions at high temperatures. A simple method for producing cyanide is the BMA (Blausaeure aus Methane und Ammoniak) process, in which methane and ammonia are reacted at approximately 1200-1300°C. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] PCT / EP2019 / 062423 [Patent Document 2] PCT / EP2019 / 062424 Summary of the Invention [Problem to be solved by the invention]

[0004] However, because the process requires high investment compared to the relatively small demand for hydrogen cyanide, there is little industrial use, with only four plants in operation as of 2003. Hydrogen cyanide is highly toxic, so there are strict regulations regarding its production, storage, and transportation.

[0005] Therefore, it is desirable to produce hydrogen cyanide "on demand" where it is needed. Ideally, hydrogen cyanide production would be done from starting materials that are cheap, safe, and commonly available in industrial chemical plants. This would reduce or eliminate the need for storage and transportation of hydrogen cyanide. In addition, rapid start-up and shutdown would allow for less storage of hydrogen cyanide.

[0006] It is also desirable for the reactor system to be a compact, easy to operate device, allowing for less hazardous handling of the hydrogen cyanide and / or nitriles. Another advantage of the present technology is that the overall emissions of carbon dioxide and other climate-harming emissions can be significantly reduced, especially if the power used in the reactor system is from renewable energy sources.

[0007] Systems and methods for steam methane reforming are described in co-pending patent application PCT / EP2019 / 062423. Systems and methods for carrying out endothermic catalytic reactions are described in co-pending patent application PCT / EP2019 / 062424. [Means for solving the problem]

[0008] overview Thus, in a first aspect, the present invention relates to a reactor system for carrying out a reaction (in particular a BMA reaction) of a feed gas comprising an alkane (in particular methane) and ammonia to hydrogen cyanide and / or nitriles in the presence of a catalyst (in particular a BMA catalyst), e.g. under BMA reaction conditions, said reactor system comprising: - provision of a feed gas comprising alkanes such as methane and ammonia; a structured catalyst arranged to catalyze a reaction of the feed gas; wherein the structured catalyst comprises a macrostructure of an electrically conductive material, the macrostructure supporting a ceramic coating, the ceramic coating supporting a catalytically active material; a pressure shell housing the structural catalyst; wherein the pressure shell comprises an inlet for admitting the feed gas and an outlet for discharging a product gas, the inlet positioned such that the feed gas enters the structural catalyst at a first end thereof and the product gas exits the structural catalyst at a second end thereof; - an insulating layer between the structural catalyst and the pressure shell; - at least two conductors electrically connected to the structural catalyst and a power source disposed outside the pressure shell; wherein the power source is dimensioned to heat at least a portion of the structural catalyst to a temperature of at least 500°C by passing an electric current through the macrostructure, and wherein the at least two conductors are connected to the structural catalyst at a location on the structural catalyst closer to the first end of the structural catalyst than to the second end of the structural catalyst, and the structural catalyst is configured to pass an electric current from one conductor to the second end of the structural catalyst and back to the second conductor of the at least two conductors. - An outlet for a product stream containing hydrogen cyanide and / or nitriles.

[0009] In a further aspect, there is provided a method for reacting a feed gas comprising alkanes, such as methane, and ammonia, in the presence of a catalyst (e.g., under BMA reaction conditions) to hydrogen cyanide and / or nitriles, the method comprising a reactor system including a pressure shell housing a structural catalyst arranged to catalyze said endothermic reaction of the feed gas, the structural catalyst comprising a macrostructure of an electrically conductive material, the macrostructure supporting a ceramic coating, the ceramic coating supporting a catalytically active material; the reactor system including thermal insulation between the structural catalyst and the pressure shell; the method comprising the steps of: - pressurizing said supply gas - supplying the pressurized feed gas to the pressure shell through an inlet arranged such that the feed gas enters the structural catalyst at a first end of the structural catalyst, reacting the feed gas on the structural catalyst, discharging a product gas from the pressure shell, and the product gas exiting the structural catalyst at a second end of the structural catalyst; - providing electrical power through electrical conductors connecting a power source disposed outside the pressure shell to the structural catalyst, and allowing electrical current to flow through the macrostructure, thereby heating at least a portion of the structural catalyst to a temperature of at least 500°C, the at least two conductors being connected to the structural catalyst at a location on the structural catalyst closer to the first end of the structural catalyst than the second end of the structural catalyst, and the structural catalyst being configured to pass electrical current from one conductor substantially to the second end of the structural catalyst and back to a second of the at least two conductors, thereby heating at least a portion of the structural catalyst to a temperature sufficient for the feed gas to effect a BMA reaction on the structural catalyst; - Venting the product gas comprising hydrogen cyanide and / or nitriles from the reactor system.

[0010] In a further aspect, there is provided a method for rapidly switching a metal catalyzed reaction of a feed gas comprising an alkane, such as methane, and ammonia, from a first steady state reaction condition (A) to a second steady state reaction condition (B) or vice versa in a reactor system as described herein, said method comprising the steps of: Under the first steady-state reaction condition (A), - supplying the feed gas to the reactor system at a first total flow rate; and - providing a first electrical power through an electrical conductor connecting a power source disposed outside the pressure shell to the structural catalyst, thereby causing a first electrical current to flow through the electrically conductive material; whereby at least a portion of the structured catalyst is heated to a first temperature at which the feed gas is converted over the structured catalyst under the first steady-state reaction conditions (A) into a first product gas mixture; and discharging the first product gas from the reactor system. And, under the second steady-state reaction condition (B), - supplying the feed gas to the reactor system at a second total flow rate; and - providing a second electrical power through an electrical conductor connecting a power source disposed outside the pressure shell to the structural catalyst, thereby causing a second electrical current to flow through the conductive material; whereby at least a portion of the structured catalyst is heated to a second temperature; at which temperature the feed gas is converted over the structured catalyst under the second steady-state reaction conditions (B) into a second product gas mixture; and discharging the second product gas from the reactor system; wherein the second power is greater than the first power; and / or the second total flow rate is greater than the first total flow rate, wherein the reactor system is configured such that the second power is greater than the first power; and / or the second total flow rate is greater than the first flow rate.

[0011] Further aspects of the present invention are described in the following detailed description, examples and appended claims. [Brief description of the drawings]

[0012] Figure legend FIG. 1a is a diagram illustrating a cross-section of one embodiment of a reactor system of the present invention with a structured catalyst comprising an array of macrostructures. FIG. 1b shows the reactor system of FIG. 1a with the pressure shell and part of the insulation removed.

[0013] FIG. 2 shows an expanded view of a portion of the reactor system.

[0014] 3a and 3b are schematic cross-sectional views through one embodiment of the reactor system of the present invention including a structured catalyst.

[0015] 4 and 5 are top and side views, respectively, showing an embodiment of a structural catalyst having aligned macrostructures.

[0016] FIG. 6 is a diagram showing one embodiment of the structure catalyst of the present invention.

[0017] 7 and 8 show an embodiment of a structural catalyst having a connector.

[0018] FIG. 9 shows the equilibrium composition of CH4 (and NH3) and HCN as a function of temperature at 5 barg using equimolar feed gas of CH4 and NH3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Full Disclosure The present technology describes how an electrically heated reactor facilitates the production of hydrogen cyanide and / or nitriles via reaction on demand in a compact design.

[0020] The technique can be used to synthesize hydrogen cyanide (HCN) and / or nitriles (RCN, where R is an alkyl group). When the alkane is methane, the catalyst is a BMA catalyst and the product stream contains hydrogen cyanide.

[0021] However, when the alkane is ethane or propane, the nitrile can be prepared by a similar principle, e.g. [ka]

[0022] When the feed gas contains a mixture of methane and other alkanes, a product gas containing hydrogen cyanide and / or nitriles is obtained. In the following, the invention is described for the synthesis of HCN by the BMA reaction. However, the technology is equally suitable for the synthesis of nitriles from alkanes, as shown above.

[0023] The BMA response is summarized as follows: [ka] Here, ΔHR=251 kJ / mol. Typically, platinum (Pt) catalyst is used as the catalytically active material. The BMA process does not require O2 (e.g., as in the Andrussow process). Therefore, in this technology, the feed gas is usually oxygen-free.

[0024] The compact electroreactor using the monolith catalyst is easy to operate and allows HCN to be produced when and as much as needed with a simple start-up principle. This allows HCN to be produced in the required quantities, with little or no HCN storage required and with reduced or completely eliminated HCN transportation, making it a relatively inexpensive plant. The simple reactor and easy operation of the BMA process offer the advantage of HCN production in a non-localized plant, which reduces the risks of handling HCN.

[0025] Additionally, the use of electricity as a heat source allows for rapid start-up and shutdown (in a matter of minutes), thus reducing the need for HCN storage as the system can switch from standby to HCN production and vice versa almost instantly.

[0026] Thus, there is provided a reactor system for reacting a feed gas comprising an alkane, such as methane, and ammonia, in the presence of a catalyst, such as a BMA catalyst (e.g., under BMA reaction conditions), to hydrogen cyanide and / or nitriles, the reactor system comprising: - Providing a feed gas comprising an alkane and ammonia - a structured catalyst arranged to catalyze a reaction of said feed gas; wherein said structured catalyst comprises a macrostructure of an electrically conductive material, said macrostructure supporting a ceramic coating, said ceramic coating supporting a catalytically active material; a pressure shell housing the structural catalyst; wherein the pressure shell comprises an inlet for admitting the feed gas and an outlet for discharging a product gas, the inlet positioned such that the feed gas enters the structural catalyst at a first end of the structural catalyst and the product gas exits the structural catalyst at a second end of the structural catalyst; - an insulating layer between the structural catalyst and the pressure shell; - at least two conductors electrically connected to the structural catalyst and a power source disposed outside the pressure shell; wherein the power source is dimensioned to heat at least a portion of the structural catalyst to a temperature of at least 500°C by passing an electric current through the macrostructure, and wherein the at least two conductors are connected to the structural catalyst at a location on the structural catalyst closer to the first end of the structural catalyst than to the second end of the structural catalyst, and the structural catalyst is configured to pass an electric current from one conductor to the second end of the structural catalyst and back to the second conductor of the at least two conductors. - An outlet for a product stream containing hydrogen cyanide and / or nitriles.

[0027] In one preferred embodiment, the alkane is methane, the catalyst is a BMA catalyst, and the product stream comprises hydrogen cyanide.

[0028] The layout of the reactor system allows for the supply of pressurized feed gas to the reactor system at the inlet and directing the gas to the pressure shell of the reactor system. Inside the pressure shell, a configuration of insulating layers and inert materials is arranged to pass the feed gas through the structured catalyst and contact the catalytic material, which promotes the BMA reaction. In addition, heating of the structured catalyst provides the heat required for the endothermic reaction. Product gas from the heated structured catalyst is directed to the outlet of the reactor system.

[0029] The proximity of the catalytically active material and the electrically conductive material allows efficient heating of the catalytically active material by close thermal conduction from the resistively heated electrically conductive material. Thus, a key feature of the resistive heating process is that the energy is supplied within the body itself, rather than by thermal conduction, convection, or radiation from an external heat source. Furthermore, the hottest part of the reactor system will be within the pressure shell of the reactor system. Preferably, the power supply and the structural catalyst are dimensioned such that at least a portion of the structural catalyst reaches a temperature of at least 700°C, preferably at least 900°C, and more preferably at least 1000°C. The surface area of ​​the conductive material, the percentage of the conductive material coated with the ceramic coating, the type and structure of the ceramic coating, and the amount and composition of the catalytically active catalyst material can be tailored to the particular reaction at a given operating condition.

[0030] The conductive material is preferably a macrostructure. As used herein, the term "macrostructure" is meant to denote a structure large enough to be visible to the naked eye without magnifying devices. The dimensions of the macrostructure are typically in the centimeter or even meter range. The dimensions of the macrostructure are advantageously made to correspond at least in part to the inner dimensions of the pressure shell housing the structural catalyst, saving space for the thermal insulation layer and the conductor. Two or more macrostructures may be joined to provide an array of macrostructures having at least one outer dimension in the meter range, such as 2 m or 5 m. Such two or more macrostructures may be denoted as an "array of macrostructures". In this case, the dimensions of the array of macrostructures are advantageously manufactured to correspond at least in part to the inner dimensions of the pressure shell housing the structural catalyst (saving space for the thermal insulation layer). Arrays of macrostructures considered may range from 0.1 to 10 m. 3or more. The structure catalyst can include a single macrostructure or an array of macrostructures, where the macrostructure (or multiple macrostructures) can support a ceramic coating that supports a catalytically active material. In an array of macrostructures, the macrostructures may be electrically connected to each other, however, alternatively, the macrostructures are not electrically connected to each other. Thus, the structure catalyst can be composed of two or more macrostructures arranged adjacent to each other. The macrostructure (or multiple macrostructures) can be an extruded and sintered structure or a 3D printed structure. The 3D printed macrostructure can be provided with or without subsequent sintering.

[0031] The physical dimensions of the macrostructures may be any suitable dimensions, so the height may be less than the width of the macrostructure or vice versa.

[0032] The macrostructure supports a ceramic coating, which in turn supports a catalytically active material. The term "macrostructure supporting a ceramic coating" is meant to indicate that the macrostructure is coated with a ceramic coating on at least a portion of the surface of the macrostructure. Thus, the term does not mean that all of the surface of the macrostructure is coated with a ceramic coating, and in particular, at least the portion of the macrostructure that is electrically connected to the conductor does not have a coating thereon. The coating is a ceramic material having pores in its structure, which allows the catalytically active material to be supported on and within the coating. Advantageously, the catalytically active material comprises catalytically active particles having a size in the range of about 2 nm to about 250 nm.

[0033] Preferably, the macrostructure is manufactured by extruding a mixture of powdered metal particles and a binder into an extruded structure and then sintering the extruded structure, thereby providing a material with a high geometric surface area per volume. Preferably, the extruded structure is sintered in a reducing atmosphere to provide the macrostructure. Alternatively, the macrostructure is 3D printed by a metal additive manufacturing fusion process that does not require subsequent sintering, such as a powder bed fusion or direct energy deposition process, i.e. a 3D printing process. Examples of such powder bed fusion or direct energy deposition processes are laser beam, electron beam, or plasma 3D printing processes. Alternatively, the macrostructure may be manufactured as a 3D metal structure by a binder-based metal additive manufacturing process and then sintered at a first temperature T1 (T1>1000°C) in a non-oxidizing atmosphere to provide the macrostructure.

[0034] Prior to the second sintering in an oxidizing atmosphere, a ceramic coating containing catalytically active material is applied onto the macrostructure, and a chemical bond is formed between the ceramic coating and the macrostructure. Alternatively, the ceramic coating can be impregnated with catalytically active material after the second sintering. When a chemical bond is formed between the ceramic coating and the macrostructure, the thermal conductivity between the electrically heated macrostructure and the catalytically active material supported by the ceramic coating is particularly high, allowing a close and almost direct contact between the heat source and the catalytically active material of the structural catalyst. Due to the close proximity of the heat source and the catalytically active material, heat transfer is effective and the structural catalyst can be heated very efficiently. Thus, the reactor system can be made compact in terms of gas throughput per reactor system volume, and therefore the reactor system housing the structural catalyst can also be made compact.

[0035] As used herein, the terms "3D printing" and "3D printing" are meant to refer to metal additive manufacturing processes. Such metal additive manufacturing processes cover 3D printing processes in which material is bonded to a structure under computer control to create a three-dimensional object, where the structure is solidified, for example by sintering, to provide a macrostructure. Furthermore, such metal additive manufacturing processes also include 3D printing processes that do not require subsequent sintering, such as powder bed fusion processes or direct energy deposition processes. Examples of such powder bed fusion or direct energy deposition processes include laser beam, electron beam or plasma 3D printing processes.

[0036] Because the reactor system does not require a furnace, the overall reactor size can be significantly reduced.

[0037] The conductive material comprises Fe, Ni, Cu, Co, Cr, Al, Si or alloys thereof. Such alloys may comprise further elements such as Mn, Y, Zr, C, Co, Mo or combinations thereof. Preferably, the conductive material comprises Fe, Cr, Al or alloys thereof. Such alloys may comprise further elements such as Si, Mn, Y, Zr, C, Co, Mo or combinations thereof. Preferably, the catalytically active material is a particle having a size of 2 nm to 250 nm. Preferably, the conductor and the conductive material are made of a material different from the conductive material. The conductor may be, for example, iron, nickel, aluminum, copper, silver or alloys thereof. The ceramic coating is an electrically insulating material and will usually have a thickness of about 100 μm, for example in the range of 10 to 500 μm.

[0038] The conductive material is advantageously a coherent or consistently interconnected material in order to achieve electrical conductivity throughout the conductive material, thereby achieving thermal conductivity throughout the structure catalyst, and in particular providing heating of the catalyst material. A coherent or consistently interconnected material can ensure uniform distribution of electrical current within the conductive material, and therefore uniform distribution of heat within the structure catalyst. Throughout this text, the term "coherent" is meant to be synonymous with cohesiveness, and thus to refer to a material that is consistently interconnected or consistently bonded. The effect of the structure catalyst being a coherent or consistently interconnected material is that control of connectivity within the material of the structure catalyst, and therefore of the electrical conductivity of the conductive material, is obtained. It should be noted that the conductive material is still referred to as a coherent or consistently interconnected material, even if further improvements to the conductive material are made, such as providing slits in parts of the conductive material or implementing insulating materials within the conductive material.

[0039] Gas flow over the structural catalyst may be axial or coaxial with the current path through the structural catalyst, perpendicular to the current path, or have any other suitable direction relative to the current path.

[0040] The BMA reaction is highly endothermic. High temperatures, typically above 800-850 °C, are required to reach acceptable conversion of the feed methane.

[0041] The feed to the BMA reaction is preferably a substantially pure stream of ammonia and methane. Alternatively, the methane may be fed in a hydrocarbon mixture, for example from natural gas or town gas, with a prospective upstream upgrading step to remove a major portion of the higher hydrocarbons and potential sulfur compounds normally present in such feeds. The feed to the process may also include a recycle stream from a unit operation downstream of the reactor system. Such a recycle may be, for example, hydrogen-rich off-gas generated from an upgrading unit arranged to purify HCN from the product stream.

[0042] The feedstock for the nitrile synthesis is preferably a substantially pure alkane, such as ethane, propane, or butane, mixed with a substantially pure ammonia stream.

[0043] In one embodiment, the alkane feedstock is a mixture of several alkanes mixed with a substantially pure ammonia stream.

[0044] The term "conductive" means 10 -5 ~10 -8 The term "electrically insulating" is meant to denote a material having an electrical resistivity in the range of 10 Ω·m at 20 °C. Thus, electrically conductive materials are, for example, metals such as copper, silver, aluminum, chromium, iron, nickel, or alloys of the metals. Furthermore, the term "electrically insulating" refers to a material having an electrical resistivity of more than 10 Ω·m at 20 °C, for example more than 10 9 ~10 25 It is meant to refer to materials in the Ω·m range.

[0045] If the reactor system includes an insulating layer between the structural catalyst and the pressure shell, adequate thermal and electrical insulation between the structural catalyst and the pressure shell is obtained. The presence of an insulating layer between the pressure shell and the structural catalyst can avoid excessive heating of the pressure shell and reduce heat loss to the surroundings. Although the temperature of the structural catalyst can reach up to about 1300°C, at least in part, by using an insulating layer between the structural catalyst and the pressure shell, the temperature of the pressure shell can be kept significantly lower, for example 500°C or 100°C, which is advantageous since typical construction steels are generally not suitable for pressure-resistant applications at temperatures above 1000°C. Furthermore, the insulating layer between the pressure shell and the structural catalyst helps control the current flow in the reactor system since the insulating layer is also electrically insulating. The insulating layer can be one or more layers of solid materials such as ceramics, inert materials, fibrous materials, bricks, or gas barriers, or a combination thereof. It is therefore conceivable that the purge gas or trapped gas constitutes or forms part of the insulating layer.

[0046] Furthermore, the term "thermal insulation material" refers to a material with a thermal insulation capacity of approximately 10 W m -1 ·K -1 Please note that this is meant to indicate materials that have the following thermal conductivities: Examples of insulating materials are ceramics, bricks, alumina-based materials, zirconia-based materials, and the like.

[0047] Advantageously, relevant gaps between the structure catalyst, the insulation layer, the pressure shell, and / or other components in the reactor system are filled with an inert material, for example in the form of inert pellets. Such gaps are, for example, the gap between the underside of the structure catalyst and the bottom of the pressure shell, and the gap between the side of the structure catalyst and the insulation layer lining the pressure shell. The inert material may be, for example, a ceramic material in the form of pellets or tiles. The inert material helps to control the gas distribution through the reactor system and the gas flow through the structure catalyst. In addition, the inert material usually has a thermal insulation effect.

[0048] The pressure shell preferably has a design pressure between 2 bar and 30 bar. The actual operating pressure is determined by the endothermic reaction, the size of the plant, etc. Since the hottest part of the reactor system is an electrically conductive material, surrounded by a thermal barrier and within the pressure shell of the reactor system, the temperature of the pressure shell can be kept significantly lower than the maximum process temperature. This allows the design temperature of the pressure shell to be relatively low, for example 700°C or 500°C, preferably 300°C or 100°C, while having a maximum process temperature of 400°C, or 900°C, or 1100°C, or even up to 1300°C for the structure catalyst. The material strength is higher at the lower of these temperatures (corresponding to the design temperature of the pressure shell shown above). This provides an advantage when designing chemical reactors. Preferably, the pressure shell has a design pressure between 2 bar and 30 bar, or between 30 and 200 bar. Around 30 bar is preferred as a compromise between the economy of the process and thermodynamic limitations.

[0049] The resistivity of the conductive material is preferably 10-5 Ω m~10 -7 Resistivity in this range is between Ω·m. Materials with resistivity in this range can efficiently heat the catalyst structure when energized with a power source. Graphite has a resistivity of about 10 -5 Ω·m, Kanthal is about 10 at 20℃ -6 Ω·m, and stainless steel is approximately 10 at 20℃ -7 A conductive material has a resistivity of about 1.5·10 Ω·m at 20°C. -6 It can be made from an FeCr alloy with a resistivity of Ω·m.

[0050] Typically, the pressure shell includes an inlet for admitting process gas and an outlet for discharging product gas, the inlet being located near a first end of the pressure shell and the outlet being located near a second end of the pressure shell, and the at least two conductors are both connected to the structural catalyst at a location closer to the inlet than the outlet. The at least two conductors can be located in a substantially cooler portion of the reactor system because the inlet gas has a lower temperature than the product gas, and the conductive material becomes cold at the most upstream portion of the material due to heat consumed by the progress of the chemical reaction, and the feed gas provided through the inlet can cool the at least two conductors before being further heated by the heated structural catalyst along the path of the gas over the heated structural catalyst. In order to protect the connection between the conductor and the structural catalyst, it is advantageous to keep the temperature of all conductive elements except the conductive material low. If the temperature of the conductor and other conductive elements other than the conductive material is relatively low, there are fewer restrictions on suitable materials for the conductor and other conductive elements other than the conductive material. When the temperature of the conductive element increases, its resistivity increases, so it is desirable to prevent unnecessary heating of parts of the reactor system other than the conductive material. The term "conductive elements excluding conductive material" is meant to refer to associated conductive elements arranged to connect a power source to the structural catalyst, excluding the conductive structural catalyst itself.

[0051] It should be noted that the systems of the present invention can include any suitable number of power sources and any suitable number of conductors connecting the power source (or power sources) to the conductive material (or conductive materials) of the structural catalyst.

[0052] Preferably, the at least two conductors are routed through the pressure shell in a fitting such that the at least two conductors are electrically insulated from the pressure shell. The fitting may be, in part, a plastic and / or ceramic material. The term "fitting" is intended to mean a device that can mechanically connect two pieces of hardware in a pressure-tight configuration, whereby the pressure in the pressure shell can be maintained even though the at least two conductors are routed through it. Non-limiting examples of fittings may be an electrically insulating fitting, a dielectric fitting, a power compression seal, a compression fitting, or a flange. A pressure shell typically consists of side walls, end walls, flanges, and possibly further parts. The term "pressure shell" is meant to cover any of these parts.

[0053] The pressure shell may further include one or more inlets adjacent or associated with at least one of the fittings to allow cooling gas to flow over, around, near or within at least one conductor in said pressure shell. This cools the conductor and, as a result, keeps the temperature experienced by the fitting low. If cooling gas is not used, the conductor may be heated by the feed gas to the reactor system, resistive heating of the conductor by an applied current, and / or thermal conduction from the structure catalyst. The cooling gas may be, for example, hydrogen, argon, nitrogen, methane, ammonia, or mixtures thereof. The temperature of the cooling gas upon entry into the pressure shell may be, for example, about 100°C, 200°C, or 250°C. In an embodiment, the conductor(s) is hollow so that cooling gas can flow through the conductor(s) to cool the conductor(s) from the inside. Keeping the temperature of the fitting low, for example, around 100-200°C, facilitates a leak-resistant configuration. Typically, a portion of the feed gas, such as one of the reactants, is fed to the pressure shell as cooling gas. In another embodiment, a portion of the feed gas or a gas of the same composition as the feed gas is used as the cooling gas.

[0054] The reactor system may further comprise an inner tube in heat exchange relationship with the structure catalyst, the inner tube being adapted to withdraw product gas from the structure catalyst such that the product gas flowing through the inner tube or tubes is in heat exchange relationship with the gas flowing over the structure catalyst but is electrically isolated from the structure catalyst. This is a layout referred to herein as a bayonet reactor system. In this layout, the product gas in the inner tube assists in heating the process gas flowing over the structure catalyst. The electrical insulation between the inner tube and the structure catalyst may be a gap or distance between the inner tube and the structure catalyst, or gas in the form of an inert material loaded around the inner tube and the structure catalyst. The gas may pass through the structure catalyst in an upflow or downflow direction.

[0055] The connection between the structural catalyst and the at least two conductors may be a mechanical connection, a welded connection, a brazed connection, or a combination thereof. The structural catalyst may include end portions that are physically and electrically connected to the structural catalyst to facilitate an electrical connection between the conductive material and the at least two conductors. The term "mechanical connection" is meant to indicate a connection in which two components are mechanically held together by a screw connection or a clamp so that an electric current can flow between the components.

[0056] The conductive materials arranged in the array of conductive materials may be electrically connected to each other. The connection between the two or more conductive materials may be by mechanical connection, clamping, soldering, welding, or any combination of these connection methods. Each conductive material may include an end portion to facilitate electrical connection. The two or more conductive materials may be connected to a power source in a series or parallel connection. The electrical connection between the two or more conductive materials is advantageously coherent and uniform along the connection surface between the two or more conductive materials such that the two or more conductive materials act as a single coherent or consistent interconnected material; whereby uniform electrical conductivity throughout the two or more conductive materials is promoted. Alternatively or additionally, the structure catalyst may include an array of conductive materials that are not electrically connected to each other. Instead, the two or more electrically conductive materials are arranged together in the pressure shell but are not electrically connected to each other. In this case, the structure catalyst thus includes conductive materials connected in parallel to the power source.

[0057] Ceramic coatings, with or without catalytically active materials, can be applied directly to the metal surface of the conductive material by washcoating. Washcoating of metal surfaces is a well-known process, the description of which is given, for example, in Cybulski, A., and Moulijn, JA, “Structured catalysts and reactors”, Marcel Dekker, Inc, New York, 1998, Chapter 3, and in references therein. The ceramic coat may be applied to the surface of the conductive material and then the catalytically active material may be added, or alternatively, a ceramic coat containing the catalytically active material may be applied to the macrostructure or conductive material. The ceramic coat may be, for example, an oxide containing Al, Zr, Mg, Ce and / or Ca. Exemplary coatings are calcium aluminate or magnesium aluminum spinel. Such ceramic coatings may contain further elements such as La, Y, Ti, K or combinations thereof. The ceramic coating is an electrically insulating material and will typically have a thickness of about 100 μm, for example in the range 10 to 500 μm.

[0058] Macrostructures can be extruded and sintered or 3D printed to give uniform and coherent shapes, which can then be coated with a ceramic coating.

[0059] The conductive material and the ceramic coating may be sintered in an oxidizing atmosphere to form a chemical bond between the ceramic coating and the conductive material, which results in particularly high thermal conductivity between the conductive material and the catalytically active material supported on the ceramic coating, such that the structured catalyst is compact in terms of heat transfer to the catalytically active sites, and the reactor system housing the structured catalyst can be compact and is limited primarily by the rate of the chemical reaction.

[0060] In one embodiment, the structural catalyst has at least one electrically insulating component arranged to increase the current path between the conductors to a length greater than the maximum dimension of the structural catalyst. Providing a current path between the conductors greater than the maximum dimension of the structural catalyst may be by providing an electrically insulating component(s) arranged between the conductors and preventing current flow through a portion of the structural catalyst. Such electrically insulating components are arranged to increase the current path and therefore increase the resistance through the structural catalyst. Thereby, the current path through the structural catalyst may be, for example, 50%, 100%, 200%, 1000%, or 10000% longer than the maximum dimension of the structural catalyst.

[0061] Moreover, such electrically insulating components are arranged to direct current from one conductor closer to the first end of the structure catalyst than the second end, toward the second end of the structure catalyst, and back to a second conductor closer to the first end of the structure catalyst than the second end. Preferably, the current is arranged to flow from the first end of the structure catalyst to the second end and back to the first end. As seen in the figures, the first end of the structure catalyst is its upper end. The arrows marked "z" in Figures 5-7 indicate the z-axis along the length of the structure catalyst. The primary current path throughout the structure catalyst will have a positive or negative value of the z-coordinate of the current density vector that accompanies the majority of the length of the current path. By primary current path is meant the path of electrons through the macrostructure of the structure catalyst that has the highest current density. The primary current path can also be understood as the path with the shortest length through the macrostructure of the structure catalyst. Geometrically, the primary current path can be quantified as the maximum current density vector in a plane perpendicular to the gas flow direction in the coherent portion of the macrostructure. At the bottom of the structural catalyst, the current turns as shown in the figure, where the z coordinate of the associated current density vector is zero.

[0062] In this specification, the term coherent portion is meant to denote a cross-sectional area of ​​a macrostructure in which all walls of the coherent portion are geometrically connected to one or more other walls of the coherent portion in the same plane.

[0063] In an embodiment, the structural catalyst comprises at least one electrically insulating component arranged to direct current through the structural catalyst such that, for at least 70% of the length of the structural catalyst, the current density vector of the main current path has a non-zero component value parallel to the length of the structural catalyst. Thus, for at least 70% of the length of the structural catalyst, the current density vector will have a positive or negative component value parallel to the length of the structural catalyst. Thus, for at least 70%, e.g., 90% or 95% of the length of the structural catalyst, i.e., along the z-axis of the structural catalyst as seen in Figures 5 to 10, the current density vector of the main current path will have a positive or negative value along the z-axis. This means that the current flows from the first end of the structural catalyst to the second end, and then flows back to the first end. Heat is absorbed from the structural catalyst due to the temperature of the gas entering the first end of the structural catalyst and the endothermic BMA reaction occurring on the structural catalyst. Thus, the first end of the structure catalyst remains cooler than the second end, and this is done with a substantially continuously increasing temperature profile by making the current density vector of the main current path have a non-zero component value parallel to the length of the structure catalyst, giving a controllable reaction front. In an embodiment, the current density vector has a non-zero component value parallel to the length of the structure catalyst at 70%, preferably 80%, more preferably 90%, and even more preferably 95% of the length of the structure catalyst. It should be noted that the term "length of the structure catalyst" is meant to indicate the dimension of the structure catalyst in the direction of gas flow. In the structure catalyst as shown in the figures, the length is the longitudinal direction, i.e., its longest dimension. This is indicated in some figures by an arrow indicating z.

[0064] Non-limiting examples of insulating parts are cuts, slits, or holes in the structure. Optionally, a solid insulating material such as ceramic in the cut or slit of the structure can be used. If the solid insulating material is a porous ceramic material, catalytically active material can be advantageously incorporated into the pores, for example by impregnation. The solid insulating material in the cut or slit helps to separate the parts of the structure catalyst on the sides of the cut or slit from each other. As used herein, the term "maximum dimension of the structure catalyst" is meant to indicate the largest internal dimension of the geometric form that the structure catalyst takes up. If the structure catalyst is box-shaped, the largest dimension is the diagonal from one corner to the farthest corner, which will also be written as the space diagonal.

[0065] It should be noted that the current through the structural catalyst may be arranged to twist or wind its way through the structural catalyst with electrically insulating components arranged to increase the current path, but gases passing through the reactor system enter at one end of the reactor system and pass once over the structural catalyst before exiting the reactor system. Inert materials are advantageously present in the associated gaps between the structural catalyst and the remainder of the reactor system to ensure that gases in the reactor system pass through the structural catalyst and the present catalytic material.

[0066] The length of the gas path through the structure catalyst is preferably less than the length of the electrical current path from one electrode through the structure catalyst to the next electrode. The ratio of the length of the gas path to the length of the electrical current path may be less than 0.6, or less than 0.3, or less than 0.1, or even less than 0.002.

[0067] Typically, the structural catalyst has electrically insulating components arranged such that the current path through the structural catalyst is a zigzag path. Here, the terms "zigzag path" and "zigzag route" are meant to indicate a path with variable angle corners that trace a path from one conductor to another. A zigzag path is, for example, a path that goes up, turns, and then goes down. A zigzag path may be sufficient with one turn, or may have a path that turns multiple times through the structural catalyst, goes up, and then goes down.

[0068] It should be noted that insulating components placed to increase the current path do not necessarily refer to a ceramic coating on the conductive material, which is also considered electrically insulating, but does not change the length of the current path between conductors connected to the conductive material.

[0069] The macrostructure can have a plurality of parallel channels, a plurality of non-parallel channels, and / or a plurality of labyrinth channels, the channels having walls that define the channels. Several different forms of macrostructures can be used, so long as the surface area of ​​the structure catalyst exposed to the gas is as large as possible. In a preferred embodiment, the macrostructure has parallel channels, since such parallel channels provide a structure catalyst with very low pressure loss. In a preferred embodiment, the parallel longitudinal channels are distorted in the longitudinal direction of the macrostructure. In this way, the gas molecules flowing through the macrostructure tend to mostly bump into the walls in the channel, rather than just flowing in a straight line through the channel without contacting the walls. The dimensions of the channels need to be appropriate to provide the macrostructure with sufficient resistivity. For example, the channels can be quadratic (as viewed in cross section perpendicular to the channels) and have a square side length between 1 and 3 mm, although channels having a maximum extent in cross section of up to about 4 cm are contemplated. The walls may have a thickness of, for example, 0.2 to 2 mm, for example about 0.5 mm, and the ceramic coating supported by the walls has a thickness of 10 μm to 500 μm, for example 50 μm to 200 μm, for example 100 μm. In another embodiment, the macrostructure of the structure catalyst is cross-corrugated.

[0070] In general, when the macrostructures are extruded or 3D printed, the pressure drop from the inlet to the outlet of the reactor system can be significantly reduced compared to reactors where the catalyst material is in the form of pellets.

[0071] Suitably, the reactor system further comprises a bed of a second catalytic material upstream of the structural catalyst in the pressure shell. Here, the term "upstream" is taken from the flow direction of the feed gas. Thus, the term "upstream" here means that the feed gas is led through a bed of the second catalytic material before reaching the structural catalyst. This provides a situation where the second catalytic material can be arranged to precondition the feed flow. The bed of the second catalytic material does not need to be specifically heated; however, if the bed of the second catalytic material is in close proximity to the structural catalyst, it can be heated indirectly. Alternatively, the second catalytic material may be heated. For clarity of the terminology used herein, it is noted that the term "structural catalyst" may also be written as "first catalytic material" to distinguish it from the second and / or third and / or fourth catalytic materials.

[0072] The reactor system may further comprise a third catalyst material in the form of catalyst pellets, extrudates or granules that are loaded into the channels of the macrostructure. In this embodiment, the reactor system will thus have a catalytically active material in the coating of the macrostructure and a third catalyst material in the form of catalyst pellets, extrudates or granules in the channels of the macrostructure. The pellets are prepared with dimensions that loosely match the size of the channels, for example, to form a single row of pellets stacked on top of each other in the channels of the macrostructure. Alternatively, the pellets, extrudates or granules may be prepared with dimensions that are significantly smaller than the size of the channels, to form a packed bed in each channel. As used herein, the term "pellets" is meant to indicate any well-defined structure having a maximum outer dimension in the range of millimeters or centimeters, while "extrudates" and "granules" are meant to define catalyst materials having a maximum outer dimension defined within a certain range.

[0073] A bed of a fourth catalytic material may be disposed within the pressure shell and downstream of the structural catalyst. Such fourth catalytic material may be in the form of catalytic pellets, extrudates or granules.

[0074] Thus, the first, second, third, and fourth catalytic materials can be catalytic materials suitable for the BMA reaction. In one embodiment, the catalyst is Pt / Al2O3. In another embodiment, it is CoSn / Al2O3. Also, in configurations that include a combination of the second, third, and fourth catalytic materials in the reactor system, the catalyst of each catalytic material can be different.

[0075] The geometric surface area of ​​the macrostructure is between 100 and 3000 m 2 / m 3 , for example, 500~1100m 2 / m 3 Typically, the material of the macrostructure can be heated to a temperature of 500 W / m by resistive heating of the material. 2 ~50000W / m 2 Preferably, the material is arranged to provide a heat flux of 5 kW / m by resistive heating of the material. 2 More than 12kW / m 2 Below, for example, 8kW / m 2 More than 10kW / m 2 The following heat flux is provided: Heat flux is given as heat per geometric surface area of ​​the surface exposed to the gas.

[0076] In one embodiment, the structural catalyst comprises a first portion arranged to generate a first heat flux and a second portion arranged to generate a second heat flux, the first heat flux being lower than the second heat flux, and the first portion being upstream of the second portion. Here, the term "the first portion being upstream of the second portion" is meant to indicate that the gas supplied to the reactor system reaches the first portion before reaching the second portion. The first portion and the second portion of the structural catalyst may be two different macrostructures supporting a ceramic coating supporting a catalytically active material, and the two different macrostructures may be arranged to generate different heat fluxes for a given current and voltage. For example, the first portion of the structural catalyst may have a large surface area and the second portion of the structural catalyst may have a smaller surface area. This can be achieved by providing the second portion of the structural catalyst with a structural catalyst having a cross-sectional area smaller than the cross-sectional area of ​​the first portion. Alternatively, the current path through the first portion of the structure catalyst may be more linear than the current path through the second portion of the structure catalyst, and thus the current twists and turns more through the second portion of the structure catalyst than through the first portion, thereby generating more heat in the second portion of the structure catalyst than in the first portion. As mentioned above, slits or cuts in the macrostructure may cause the current path to zigzag through the macrostructure. It should be noted that the first and second portions of the structure catalyst may receive different currents and voltages so that they can provide different heat fluxes. However, different heat fluxes of the first and second portions may also be achieved by providing the same current and voltage through / on the first and second portions due to the different physical properties of the first and second portions as shown above. In a further embodiment, the structural catalyst comprises a third portion arranged to generate a third heat flux, the third heat flux being lower than the first and / or second heat flux, the third portion being downstream of the first and / or second portions.

[0077] The desired temperature range for the gas exiting the pressure shell / reactor system is in the range of 200-1300°C. The product gas outlet temperature from the structure catalyst is measured directly below or at the most downstream surface of the structure catalyst. Measurement techniques can include thermocouples (by voltage drop), resistance temperature detectors, or infrared detection. The measurement point can be separate from the structure catalyst and embedded in the downstream inert gas / catalyst, or directly on the surface with an insulating surface coating.

[0078] The structure catalyst in the reactor system is preferably such that the ratio of the area equivalent diameter of the horizontal cross section passing through the structure catalyst to the height of the structure catalyst is in the range of 0.1 to 2.0. The area equivalent diameter of the cross section passing through the reactor system is defined as the diameter of a circle having an area equivalent to the area of ​​the cross section. When the ratio of the area equivalent diameter to the height of the structure catalyst is 0.1 to 2.0, the pressure shell containing the structure catalyst can be relatively small compared to other endothermic reaction reactor systems such as current tubular reformers for steam methane reforming.

[0079] Typically, as gas flows in an upflow or downflow direction in a reactor system, the gas flows through the channels in the structure catalyst along its height. When the structure catalyst includes a number of arrays or arrays of macrostructures, the individual macrostructures in the array may be arranged side-by-side, on top of each other, or a combination thereof. It is emphasized that when the structure catalyst includes two or more macrostructures, the dimensions of the structure catalyst are the dimensions of the two or more macrostructures. Thus, as an example, when the structure catalyst is composed of two macrostructures, each having a height h, placed on top of each other, the height of the structure catalyst is 2h.

[0080] The volume of the structure catalyst is selected taking into consideration the desired feed conversion and / or temperature from the reactor system which correlates to the heating value of the conductive material.

[0081] Suitably, the height of the reactor system is between 0.5 and 7 m, more preferably between 0.5 and 3 m. Exemplary values ​​for the height of the reactor system are less than 5 m, preferably less than 2 m, or even 1 m in height. The dimensions of the reactor system and the dimensions of the structure catalyst within the reactor system are interrelated. Of course, the pressure shell and the insulating layer make the reactor system somewhat larger than the structure catalyst itself.

[0082] The reactor system may further include an upgrading unit positioned to receive and separate a product stream comprising hydrogen cyanide into an upgraded hydrogen cyanide stream and an off-gas stream.

[0083] The reactor system described above is not an isolated system, in contrast to sintered BMA reactors. There is no heat transfer across the pressure walls, so there is no high risk of mechanical failure. From the catalyst's point of view, temporary overheating is not an issue, just the production of very hot gases. This means that start-up is relatively fast, in fact the invention can be started by applying a pre-determined voltage, after which the system will operate towards thermal equilibrium to reach steady state without additional operator input.

[0084] A method is provided for carrying out the reaction of a feed gas comprising alkanes such as methane and ammonia in the presence of a catalyst, such as a BMA catalyst (e.g., under BMA reaction conditions), into hydrogen cyanide and / or nitriles in a reactor system including a pressure shell containing a structural catalyst arranged to catalyze the endothermic reaction of the feed gas, the structural catalyst comprising a macrostructure of an electrically conductive material, the macrostructure supporting a ceramic coating, the ceramic coating supporting a catalytically active material; and the reactor system including thermal insulation between the structural catalyst and the pressure shell.

[0085] The method includes the following steps. - pressurizing said supply gas - supplying the pressurized feed gas to the pressure shell through an inlet arranged such that the feed gas enters the structural catalyst at a first end of the structural catalyst, reacting the feed gas on the structural catalyst, discharging a product gas from the pressure shell, and the product gas exiting the structural catalyst at a second end of the structural catalyst; - providing electrical power via electrical conductors connecting a power source disposed outside the pressure shell to the structural catalyst, and allowing electrical current to flow through the macrostructure, thereby heating at least a portion of the structural catalyst to a temperature of at least 500°C, the at least two conductors being connected to the structural catalyst at a location on the structural catalyst closer to the first end of the structural catalyst than the second end of the structural catalyst, and the structural catalyst being configured to pass electrical current from one conductor substantially to the second end of the structural catalyst and back to the second of the at least two conductors, thereby heating at least a portion of the structural catalyst to a temperature sufficient for the feed gas to carry out a BMA reaction on the structural catalyst; - Venting the product gas comprising hydrogen cyanide and / or nitriles from the reactor system.

[0086] All details of the above system are relevant to the above method, wherever possible.

[0087] In one embodiment, the feed gas is pressurized to a pressure between 2 and 30 bar. The feed gas may be pressurized to a pressure between 30 and 200 bar. Suitably, at least a portion of the structure catalyst is heated to a temperature of at least 700°C, preferably at least 900°C, more preferably at least 1000°C. The maximum temperature to which the structure catalyst is heated is about 1400°C.

[0088] In one aspect of the method, the method further includes flowing a cooling gas through an inlet through the pressure shell to cause the cooling gas to flow over at least one conductor.

[0089] Suitably, in the process of the present invention, the alkane is methane, the catalyst is a BMA catalyst and the product stream comprises hydrogen cyanide.

[0090] The method may further include feeding the product stream comprising hydrogen cyanide to an upgrading unit and separating it into an upgraded hydrogen cyanide stream and an off-gas stream. The upgrading unit may be arranged such that the off-gas stream is recycled and mixed with the feed gas supply prior to passing over the structured catalyst.

[0091] The upgrading unit may include a combination of absorbers, scrubbers, strippers, and condensers. In one embodiment, the process gas from the reactor system is passed through a monoammonium phosphate solution to remove ammonia. The resulting stream is then passed through an HCN adsorber that uses cold water to retain the HCN, and the solution is sent to an HCN stripper for product purification. In another embodiment, the process gas from the reactor system is passed through a sulfuric acid scrubber to remove ammonia. The resulting stream is then passed through an HCN adsorber that uses cold water to retain the HCN, and the solution is sent to an HCN stripper for product purification.

[0092] In one embodiment, the method further comprises feeding the upgraded hydrogen cyanide stream from the upgrading unit to a downstream plant for HCN conversion to an upgraded product, where the production of HCN equals the consumption of HCN in the downstream plant. This means that HCN is produced "on demand" so that there is no intermediate inventory of HCN to be stored or transported. Examples of upgraded products include acetone cyanohydrin, adiponitrile, sodium cyanide, methionine, cyanuric chloride, etc.

[0093] Thus, in the reactor systems described herein, methods are provided for rapidly switching a metal-catalyzed reaction of a feed gas comprising methane and ammonia from a first steady-state reaction condition (A) to a second steady-state reaction condition (B) or vice versa.

[0094] Reaching steady state is defined as when a central process parameter (feed flow rate, outlet temperature, reactant conversion, etc.) reaches a value that is within ±15% of the average process value of the given process parameter for the subsequent time period.

[0095] Conditions A and B of the present invention are a method for feeding a feedstock containing methane, ammonia, and any one of hydrogen, nitrogen, argon, and oxygen at a rate of 300 Nm 3 / h~100000Nm 3 This includes the state of heating the catalyst in a system in which the product gas outlet temperature from the structure catalyst is heated in a balanced manner with electricity (by electrical power balance) to a temperature of 300 to 1300°C at a pressure of 5 barg to 150 barg with a total flow rate of 1 / h. As the raw material passes through the monolith, it reacts toward reaction equilibrium.

[0096] In an embodiment of the invention, the process has a temperature of 430°C at a pressure of 6.7 barg and a 3 The reactor comprises initial reaction conditions A, with a total flow rate of 100 kW / h and the feed consisting of 49.6% CH4, 49.6% NH3, 0.2% N2 and 0.6% H2. Upon supplying a first power of 100 kW, a near equilibrium gas consisting of 46.3% CH4, 46.3% NH3, 0.2% N2, 5.6% H2 and 1.7% HCN is produced at a pressure of 6.6 barg, a temperature of 600°C and a flow rate of 566 Nm 3 When switching to condition B over a period of about 90 minutes with a second power of 1090 kW, a near equilibrium gas consisting of 5.0% CH4, 5.0% NH3, 0.1% N2, 67.6% H2, and 22.4% HCN was produced at a pressure of 6.6 bar, a temperature of 1130°C, and a flow rate of 992 Nm 3 / h total flow rate.

[0097] In an embodiment of the invention, the process has a temperature of 430°C at a pressure of 34.3 barg and a 3 The reactor contains initial reaction conditions A, with a total flow rate of 1000 sq. m / h and the feed consists of 48.4% CH4, 48.4% NH3, 0.8% N2 and 2.4% H2. Upon supplying a first power of 200 kW, a near equilibrium gas consisting of 13.0% CH4, 13.0% NH3, 0.5% N2, 55.5% H2 and 18.0% HCN has a pressure of 34.0 barg, a temperature of 1150°C and a flow rate of 199 Nm 3 A second power supply of 580 kW was applied and switched to condition B for approximately 25 minutes, resulting in a total supply flow of 381 Nm 3 / h, it has a temperature of 1135°C at a pressure of 34 bar and a force of 586 Nm 3 At a total flow rate of 1000 / h, approximately equilibrium gas is produced containing 14.0% CH4, 14.0% NH3, 0.5% N2, 54.1% H2 and 17.5% HCN.

[0098] The term "reverse" is used herein to mean when switching from a first reaction condition (A) to a second reaction condition (B) as well as when switching from a second reaction condition (B) to a first reaction condition (A). It is noteworthy that the switch from condition A to B is considered complete when the process value of the system reaches within 85% of the steady state condition.

[0099] The reactor system is as described above; namely, a pressure shell housing a structural catalyst arranged to catalyze the reaction of a feed gas comprising methane and ammonia, said structural catalyst comprising a macrostructure of electrically conductive material, said macrostructure supporting a ceramic coating, said ceramic coating supporting a catalytically active material, said reactor system being provided with thermal insulation between said structural catalyst and said pressure shell. All details mentioned above in relation to the reactor system are relevant to the present technology.

[0100] The method of this aspect of the invention comprises the following steps. Under the first steady-state reaction condition (A), - supplying the feed gas to the reactor system at a first total flow rate; and - providing a first electrical power through an electrical conductor connecting a power source disposed outside the pressure shell to the structural catalyst, thereby causing a first electrical current to flow through the electrically conductive material; whereby at least a portion of the structured catalyst is heated to a first temperature at which the feed gas is converted over the structured catalyst under the first steady-state reaction conditions (A) into a first product gas mixture; and discharging the first product gas from the reactor system. And, under the second steady-state reaction condition (B), - supplying the feed gas to the reactor system at a second total flow rate; and - providing a second electrical power through an electrical conductor connecting a power source disposed outside the pressure shell to the structural catalyst, thereby causing a second electrical current to flow through the conductive material; whereby at least a portion of the structured catalyst is heated to a second temperature; at which temperature the feed gas is converted over the structured catalyst under the second steady-state reaction conditions (B) into a second product gas mixture; and discharging the second product gas from the reactor system.

[0101] To achieve said first and second steady state reaction conditions (A) and (B), said second power is greater than said first power; and / or said second total flow rate is greater than said first total flow rate.

[0102] It is worth noting that as the total flow rate increases, the input of cooling feed gas increases, so that the catalyst cools and the reactivity decreases so that the second steady-state reaction condition (B) is achieved. Large changes in the flow rate change the energy required for the process.

[0103] A change in the total flow rate may include a change in the total flow rate with no change in composition, or a change in composition such as increasing the recycle flow rate or changing some of the feedstock.

[0104] In one embodiment, the ratio (A:B) of the total gas supply flow rates in the first reaction condition A and the second reaction condition B is at least 1:10. Switching between condition A and condition B allows, as a result, a significant increase / decrease in the amount of product gas produced. This is advantageous when the invention is used for energy storage, for example, where excess electrical energy from an energy grid is available and can thus be stored as chemical energy, or vice versa, to increase the availability of electrical energy in the grid when electrical energy is needed elsewhere. Furthermore, this embodiment allows the invention to be used to supply large amounts of product gas in periods when downstream processes require it, while the invention can otherwise operate in standby. This is advantageous when there is no continuous demand for product gas.

[0105] In another embodiment, the product gas outlet temperature from the structure catalyst under reaction condition B is 50°C to 800°C higher than the product gas outlet temperature from the structure catalyst under reaction condition A, for example 100°C to 500°C higher, preferably 150°C to 400°C higher. This allows the reactor system to be quickly ramped up from a cold state to operating conditions. This is advantageous in the context of system start-up, where the start-up procedure includes steps including: heating the process equipment in a non-condensable gas to a temperature at or above the condensation point of the plant's steady-state conditions at full operation; pressurizing the feed gas components; supplying a feed gas component to the reactor system while applying a first electrical power; The second power supply switches to a higher operating temperature. In this way, all steps of the start-up procedure occur relatively quickly.

[0106] The product gas outlet temperature from the structure catalyst under reaction condition B is typically not more than 50° C. higher than the product gas outlet temperature from the structure catalyst under reaction condition A (typically only up to 50° C. higher than the product gas outlet temperature). This makes it possible to quickly change between conditions A and B without significantly changing the product gas composition from the system. In this way, product gas demands for downstream processes in the reactor system can be easily supplied in different amounts without significantly interfering with their chemical environment.

[0107] In one embodiment, switching between reaction conditions A and B includes gradually changing the total gas supply flow rate from the first total flow rate to the second total flow rate and simultaneously gradually changing the applied potential across the conductive material from the first power to the second power. In this way, the product gas composition can be kept substantially constant during the transition phase. In one embodiment, the stepwise change is performed in a manner that increases the flow rate in small increments while increasing the power in order to keep the product gas outlet temperature from the structure catalyst substantially constant.

[0108] In an embodiment, the reactor system further comprises a control system arranged to control the power source to ensure that the temperature of the gas leaving the pressure shell is within a predetermined range and / or to ensure that the conversion of the feed gas is within a predetermined range. The control of the power source is the control of the electrical output from the power source. The control of the power source can be implemented, for example, as the control of the voltage and / or current from the power source, as the control of whether the power source is turned on or off, or as a combination thereof. The power supplied to the structure catalyst can be in the form of AC or DC.

[0109] According to one embodiment, a proportional-integral-derivative (PID) controller controls the electrical potential based on a feedback reading of a process value of the product gas outlet temperature from the structure catalyst.

[0110] The methods described herein allow for rapid switching between conditions A and B. Suitably, therefore, switching between reaction conditions A and B is carried out over a period of less than 3 hours, such as less than 2 hours, for example less than 60 minutes, preferably less than 30 minutes, more preferably less than 15 minutes.

[0111] In one embodiment, switching between reaction conditions A and B includes providing a second power to the structure catalyst, preferably while keeping the total flow rate essentially constant.

[0112] In one embodiment, the switching between reaction conditions A and B includes a transition state between the reaction conditions A and B; the transition state includes a first period during which power is turned off, followed by a second period during which the structure catalyst is supplied with the second power of condition B. This allows a steady state to be established more quickly.

[0113] In one embodiment, the switching between the reaction conditions A and B includes a transition state between the reaction conditions A and B; the transition state includes a first period during which the structure catalyst is supplied with a third power, followed by a second period during which the structure catalyst is supplied with a second power of the condition B, the third power being greater than the second power. This allows a steady state to be established more quickly.

[0114] The process may include further steps performed on the product gas containing hydrogen cyanide, such as purification, pressurization, heating, cooling, etc., to provide a final product gas for application downstream of the reactor system of the invention.

[0115] It should be noted that the feed gas can include individual feed gases, and that the step of pressurizing the feed gas includes pressurizing the individual feed gases individually. Additionally, it should be noted that the order in which the steps of the method are written is not necessarily the order in which the steps of the method are performed, in that two or more steps may be performed simultaneously, or the order may differ from that shown above.

[0116] In an embodiment, the method includes pressurizing the gas upstream of the pressure shell to a pressure of at least 2 bar. The selected operating pressure is defined by the integration of the reactor in the endothermic reaction and the surrounding method steps.

[0117] In embodiments of the process according to the invention, the temperature of the feed gas entering the reactor system is between 100° C. and 700° C. In all embodiments, however, the temperature and pressure of the feed gas are adjusted to ensure that the feed gas is above its dew point.

[0118] In an embodiment of the method of the present invention, the structure catalyst is heated such that the maximum temperature of the structure catalyst is between 200°C and 1300°C. The temperature used will depend on the endothermic reaction. The maximum temperature of the structure catalyst depends on the material of the conductive material, so for an FeCr alloy where the conductive material melts at a temperature of 1380°C to 1490°C (depending on the actual alloy), the maximum temperature should be slightly lower than the melting point as the material becomes soft and ductile as it approaches the melting point, such as about 1300°C if the melting point of the conductive material is about 1400°C. The maximum temperature may further be limited by the durability of the catalyst material, coating and catalytically active material.

[0119] In an embodiment, the method according to the invention further comprises the step of injecting a cooling gas from an inlet through the pressure shell to allow the cooling gas to flow over the at least one conductor and / or fitting. The cooling gas may advantageously be hydrogen, nitrogen, ammonia, methane or any other gas suitable for cooling an area or zone around the at least one conductor. A portion of the supply gas may be fed to the pressure shell as the cooling gas.

[0120] In an embodiment according to the invention, the method further comprises injecting cooling gas from an inlet through the pressure shell to cause the cooling gas to flow over at least one conductor and / or fitting. The cooling gas may be any suitable gas; examples of such gases are hydrogen, nitrogen, ammonia, methane or mixtures thereof. The cooling gas may flow through the conductor(s) and cool it(s) from within; in this case the conductor(s) must be hollow to accommodate the cooling gas flowing through / among them.

[0121] The catalytic material for the reaction may be Pt / Al2O3, Pt / ZrO2, Ru / Al2O3, Rh / MgAl2O3, Pt / MgAl2O3, or CoSn / Al2O3. The catalytically active material may be Pt, Ru, Rh, Ir, Co, Sn, or a combination thereof, and the ceramic coating may be mixed with Al2O3, ZrO2, MgAl2O3, CaAl2O3, or a combination thereof, and potentially with oxides of Y, Ti, La, or Ce. The maximum temperature of the reactor may be between 850 and 1300°C. The pressure of the feed gas may be between 2 and 180 bar, preferably about 25 bar. In an embodiment, the macrostructure is made of an alloy of FeCrAl supporting a ceramic coating of ZrO2 and Al2O3 mixture, with Pt as catalytically active material.

[0122] Detailed Description of the Drawings In the diagram legend below, the BMA reaction is described, but details such as the reactor apparatus also apply to the nitrile synthesis. In the drawings, like reference numbers indicate like elements.

[0123] FIG. 1a is a cross-sectional view through one embodiment of a reactor system 100 according to the present invention. The reactor system 100 comprises a structural catalyst 10 arranged as an array of macrostructures 5. Each macrostructure 5 in the array is coated with a ceramic coating impregnated with a catalytically active material. The reactor system 100 further comprises conductors 40, 40' connected to a power source (not shown) and to the structural catalyst 10, i.e., the array of macrostructures. The conductors 40, 40' are routed through the wall of the pressure shell 20 that contains the structural catalyst, through the insulating material 30 inside the pressure shell, and through fittings 50. The conductors 40' are connected to the array of macrostructures 5 by conductor contact rails 41.

[0124] In an embodiment, the power supply provides a voltage of 26V and a current of 1200A. In another embodiment, the power supply provides a voltage of 5V and a current of 240A. The current is conducted to the conductor contact rails 41 via electrical conductors 40, 40', and the current flows through the structural catalyst 10 from one conductor contact rail 41, e.g., the conductor contact rail seen on the left side in FIG. 1a, to the other conductor contact rail 41, e.g., the conductor contact rail seen on the right side in FIG. 1a. The current can be an alternating current, e.g., flowing alternately in both directions, or a direct current, flowing in either of two directions.

[0125] The macrostructure 5 is made of an electrically conductive material. Particularly preferred is the alloy Kanthal, which is made of aluminum, iron and chromium. A ceramic coating, e.g. an oxide, applied to the structural catalyst 5 is impregnated with a catalytically active substance. The conductors 40, 40' are made of materials such as iron, aluminum, nickel, copper or alloys thereof.

[0126] In operation, a feed gas containing methane and ammonia enters the reactor system 100 from the top, as indicated by arrow 11. A product stream exits the reactor system from the bottom, as indicated by arrow 12.

[0127] FIG. 1b shows the reactor system 100 of FIG. 1a with a portion of the pressure shell 20 and the layer of insulating material 30 removed, and FIG. 2 shows an enlarged view of a portion of the reactor system 100. In FIG. 1b and FIG. 2, the connection between the conductor 40' and the conductor contact rail 41 is shown more clearly than in FIG. 1a. It can further be seen that the conductor 40 is routed through the wall of the pressure shell at fittings 50, splitting the single conductor 40 into three conductors 40' within the pressure shell. It should be noted that the number of conductors 40' may be any suitable number, such as less than three or more than three.

[0128] In the reactor system shown in Figures 1a, 1b and 2, the conductors 40, 40' are conducted through the wall of the pressure shell 20 containing the structural catalyst, through the insulating material 30 inside the pressure shell, via the fitting 50. The feed gas for the BMA reaction enters the reactor system 100 through an inlet at the top of the reactor system 100, as shown by arrow 11, and the converted product stream exits the reactor system 100 through an outlet at the bottom of the reactor system 100, as shown by arrow 12. In addition, one or more additional inlets (not shown in Figures 1a-2) are advantageously present near or in combination with the fitting 50. Such additional inlets allow a cooling gas to flow over, around, near or inside at least one conductor in the pressure shell to reduce heating of the fitting. The cooling gas can be, for example, hydrogen, nitrogen, methane or mixtures thereof. The temperature of the cooling gas upon entry into the pressure shell can be, for example, about 100°C.

[0129] In the reactor system 100 shown in Figures 1a-2, an inert material (not shown in Figures 1a-2) is advantageously present between the underside of the structural catalyst 10 and the bottom of the pressure shell. Furthermore, the inert material is advantageously present between the outer side of the structural catalyst 10 of the macrostructure 5 and the insulating material 30. Thus, one side of the insulating material 30 faces the inside of the pressure shell 20, and the other side of the insulating material 30 faces the inert material. The inert material is, for example, a ceramic material and may be in the form of pellets. The inert material helps to control the pressure loss across the reactor system 100 and to control the flow of gas through the reactor system 100, so that the gas flows over the surface of the structural catalyst 10.

[0130] 3a and 3b are schematic diagrams of a cross section according to one embodiment of a reactor system 100', 100'' of the present invention including a structural catalyst 10'. The structural catalyst 10' may be composed of a single macrostructure having a ceramic coating supporting catalytically active material, or may include two or more macrostructures. Each of the reactor systems 100', 100'' includes a pressure shell 20 and an insulating layer 80 between the structural catalyst 10' and the pressure shell 20. An inert material 90 can be used to fill the gap between the structural catalyst 10' and the insulating layer or pressure shell 20. In Figs. 3a and 3b, the inert material 90 is shown by the dotted area, and the inert material 90 can be in any suitable form, for example, in the form of inert pellets, which are made of a ceramic material, for example. The inert material 90 helps to control the pressure drop through the reactor system and to control the flow of gas through the reactor system. In addition, the inert material typically has a thermal insulating effect.

[0131] From Figures 3a and 3b, it can be seen that the reactor system 100', 100'' further includes an inner tube 15 in heat exchange relationship with the structural catalyst 10'. The inner tube 15 is adapted to draw product gas from the structural catalyst 10' such that the product gas flowing through the inner tube or tube is in heat exchange relationship with the gas flowing over the structural catalyst, but the inner tube 15 is electrically insulated from the structural catalyst 10' by either an insulating layer 80, an inert material 90, a gap, or a combination. This is a layout described as a bayonet reactor system. In this layout, the product gas in the inner tube assists in heating the process gas flowing over the macrostructure. In the layout shown in Figures 3a and 3b, the feed gas enters the reactor system 100', 100'' as shown by arrow 11 and subsequently enters the structural catalyst 10' as shown by arrow 13. While the feed gas passes over the structural catalyst 10', it undergoes the BMA reaction. The gas exiting the structural catalyst 10' is at least partially converted to hydrogen cyanide. At least partially converted gas flows from the structural catalyst 10' into the inner tube 15 as shown by arrow 14 and out of the inner tube as shown by arrow 12. Even though there is a thermal barrier 80 between the inner tube 15 and the structural catalyst 10', some heat transfer will occur between the gas in the inner tube 15 and the gas in or upstream of the structural catalyst 10'. In the embodiment shown in Figures 3a and 3b, the feed gas flows down the structural catalyst 10' and up the inner tube 15; however, it is also contemplated to turn the configuration upside down so that the feed gas flows up the structural catalyst 10' and down the inner tube 15.

[0132] 4 and 5 show an embodiment of a structural catalyst including an array of macrostructures, respectively viewed from above and from the side. FIG. 4 shows a structural catalyst 10 including an array of macrostructures 5, viewed from above, i.e., from the arrow 11 in FIG. 1a and FIG. 1b. The array has six rows of five macrostructures 5, i.e., 1a, 1b, 1c, 1d, 1e and 1f. The macrostructure 5 of each row is connected to its adjacent macrostructures (macrostructures) of the same row, and the two outermost macrostructures of each row are connected to the conductor contact rail 41. Adjacent macrostructures 5 of a row of macrostructures are connected to each other by a connecting piece 3.

[0133] FIG. 5 is a side view of the structural catalyst 10 having a row of macrostructures 5 of FIG. 4. From FIG. 5, it can be seen that each macrostructure 5 extends longitudinally perpendicular to the cross section seen in FIG. 4. Each macrostructure 5 has a slit 60 cut along its longitudinal direction (see FIG. 5). Thus, when energized by a power source, current enters the array of macrostructures 5 via the conductor contact rail 41, is guided downward through the first macrostructure 5 to the lower limit of the slit 60, and then is guided upward toward the connecting piece 3. The current is guided downward and upward through each macrostructure 5 of each row 1a-1f of macrostructures 5 in the array 10 via a corresponding zigzag path. This configuration advantageously increases the resistance (resistance) on the structural catalyst 10.

[0134] FIG. 6 is a perspective view of a structural catalyst 10 according to the present invention. The structural catalyst 10 includes a macrostructure coated with a ceramic coating impregnated with a catalytically active material. Within the structural catalyst are channels 70 that run along the length of the macrostructure 5 (indicated by the arrow "h" in FIG. 6), and the channels are defined by walls 75. In the embodiment shown in FIG. 6, the walls 75 define a number of parallel square channels 70 when viewed in the direction of flow as indicated by the arrow 12. When viewed from above, the structural catalyst 10 has a substantially square perimeter defined by edge lengths e1 and e2. However, the perimeter can also be circular or another shape.

[0135] The walls 75 of the structural catalyst 10 are ceramic coatings, such as oxide coated extruded or 3D printed materials, coated on the macrostructure. In the figures, the ceramic coatings are not shown. The ceramic coatings are impregnated with catalytically active materials. The ceramic coatings, and therefore the catalytically active materials, are present on all walls within the structural catalyst 10 through which the gas stream flows during operation and which interact with the heated surfaces of the structural catalyst and the catalytically active materials.

[0136] Thus, during use in a reactor system for a BMA reaction, feed gas flows through channels 70 and interacts with the heated surfaces of the structural catalyst and catalytically active material supported by the ceramic coating.

[0137] In the structural catalyst 10 shown in Figure 6, a slit 60 is cut into the structural catalyst 10. The slit 60 forces the current to take a zigzag path within the macrostructure, in this example downward then upward, thereby increasing the current path and therefore the resistance and therefore the heat dissipated within the macrostructure. The slit 60 in the macrostructure may be provided with an embedded insulating material to prevent current flow across the slit 60.

[0138] The channels 70 in the structured catalyst 10 are open at both ends. When the structured catalyst is used in a reactor system, the feed gas flows through the unit in the direction shown by arrows 11 and 12 in Figures 1a and 1b and is heated by contact with the walls 75 of the channels 70 and thermal radiation. This heat initiates the desired BMA reaction. The walls 75 of the channels 70 may have a thickness of, for example, 0.5 mm, and the ceramic coating on the walls 75 may have a thickness of, for example, 0.1 mm. Although the arrows 11 and 12 (see Figures 1a and 1b) indicate that the feed gas flow is downflow, the opposite flow direction, i.e., upflow, is also contemplated.

[0139] FIG. 7 shows the structural catalyst 10 of FIG. 1a and FIG. 1b in a perspective view, with the connector 7 attached. The connectors 7 each connect a portion of the structural catalyst 10 to a conductor 40. The conductors 40 are all connected to a power source (not shown). Each of the connectors 7 is connected to the top of the structural catalyst. When the conductors 40 are connected to a power source, a current is conducted through the conductor to the corresponding connector 7 and flows through the structural catalyst 10. The slits 60 prevent the flow of current in the lateral direction (horizontal direction in FIG. 7) throughout the entire length of the structural catalyst 10 along its height h. Thus, the current flows downwards as seen in FIG. 7 in the portion of the structural catalyst along the slits 60, then flows longitudinally transversely below the slits 60 as seen in FIG. 7, and finally the current flows upwards in the longitudinal direction of the structural catalyst to reach the other connector 7. The connectors 7 in FIG. 7 are mechanically fastened to the structural catalyst by mechanical fastening means, in particular screws or bolts. However, additional or alternative fastening means are also conceivable. In one embodiment, the power supply generates a voltage of 3 V and a current of 400 A. The connector 7 is made of a material such as, for example, iron, aluminum, nickel, copper or alloys thereof.

[0140] As mentioned above, the structural catalyst 10 is coated with a ceramic coating, such as an oxide, that supports catalytically active materials. However, the portion of the structural catalyst 10 that is connected to the connector 7 must not be coated with an oxide. Instead, the macrostructure of the structural catalyst needs to be directly exposed or connected to the connector 7 in order to obtain a good electrical connection between the macrostructure and the connector.

[0141] If the connector 7 and thus the conductor 40 are connected to the same end of the structural catalyst 10, i.e., the top end as seen in FIG. 7, the feed gas entering the reactor system containing the structural catalyst 10 will be able to cool the connector 7 and the conductor 40. For example, the feed gas entering such a reactor system may have a temperature of 200° C. or 400° C., thus preventing the connector 7 and the conductor 40 from reaching a temperature much higher than this temperature.

[0142] FIG. 8 shows another embodiment of a structural catalyst 10'' with connectors 7''. The structural catalyst 10''' is, for example, a structural catalyst as shown in FIG. 6. Each of the connectors 7''' (not shown) has three holes on its upper side for connecting to conductors. Inside the slits 60 (see FIG. 6) of the structural catalyst 10''' is a piece of electrical insulation material 61.

[0143] Figure 9 shows the equilibrium composition of CH4 (and NH3) vs HCN as a function of temperature at 5 barg using equimolar feed gas of CH4 and NH3. It shows the thermodynamic equilibrium composition as a function of temperature. It should be noted that although only methane is shown as a reactant, this concentration is equivalent to the ammonia concentration by 1:1 stoichiometry since the feed gases are equimolar. According to the figure, to obtain a high conversion of methane, the reaction temperature must be above 1000°C, with the remaining mole fraction of methane still being 10.3%. Ideally, a reaction temperature of 1200°C or higher would result in a gas composition of 2.4% methane, 2.4% ammonia, 23.8% hydrogen cyanide, with the balance being hydrogen.

[0144] It should be noted that although the structure catalyst in the figures is shown as a channel with a square cross section when viewed perpendicular to the z-axis, the cross section of the channel can be any suitable shape. Thus, the structure catalyst channel can alternatively be, for example, triangular, hexagonal, octagonal, or circular, with triangular, square, and hexagonal shapes being preferred.

[0145] The present invention has been illustrated by the description of various embodiments and examples, and while these embodiments and examples have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such details. Additional advantages and modifications will readily occur to those skilled in the art. Thus, the invention in its broader aspects is not limited to the specific details, representative methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the applicant's general inventive concept.

[0146] Item of the present invention 1. A reactor system for carrying out a reaction of a feed gas containing an alkane and ammonia to hydrogen cyanide and / or nitriles in the presence of a catalyst, said reactor system comprising: - providing a feed gas comprising an alkane and ammonia; a structured catalyst arranged to catalyze a reaction of the feed gas; wherein the structured catalyst comprises a macrostructure of an electrically conductive material, the macrostructure supporting a ceramic coating, the ceramic coating supporting a catalytically active material; a pressure shell housing the structural catalyst; wherein the pressure shell comprises an inlet for admitting the feed gas and an outlet for discharging a product gas, the inlet positioned such that the feed gas enters the structural catalyst at a first end thereof and the product gas exits the structural catalyst at a second end thereof; - an insulating layer between the structural catalyst and the pressure shell; - at least two conductors electrically connected to the structural catalyst and a power source disposed outside the pressure shell; wherein the power source is dimensioned to heat at least a portion of the structural catalyst to a temperature of at least 500°C by passing an electric current through the macrostructure, and wherein the at least two conductors are connected to the structural catalyst at a location on the structural catalyst closer to the first end of the structural catalyst than to the second end of the structural catalyst, and the structural catalyst is configured to pass an electric current from one conductor to the second end of the structural catalyst and back to the second of the at least two conductors. - An outlet for a product stream containing hydrogen cyanide and / or nitriles.

[0147] 2. The reactor system of claim 1, wherein the power source is dimensioned to heat at least a portion of the structure catalyst to a temperature of at least 700°C, preferably at least 900°C, and more preferably at least 1000°C.

[0148] 3. The reactor system of any one of the preceding claims, wherein the feed gas further comprises H2, N2, or Ar.

[0149] 4. The reactor system according to any one of the preceding items, wherein the pressure shell has a design pressure between 2 and 30 bar.

[0150] 5. The reactor system according to any one of items 1 to 3, wherein the pressure shell has a design pressure between 30 and 200 bar.

[0151] 6. The resistivity of a conductive material is 10 -5 Ω m~10 -7 Item 11. The reactor system of any one of the preceding items, wherein the thermal conductivity is between 100 and 150 Ω·m.

[0152] 7. The reactor system of any one of the preceding items, wherein the at least two conductors are routed through the pressure shell at fittings such that the at least two conductors are electrically insulated from the pressure shell.

[0153] 8. The reactor system of item 7, wherein the pressure shell further comprises one or more inlets adjacent or in combination with at least one fitting to allow cooling gas to flow over, around, adjacent to or within at least one conductor within the pressure shell.

[0154] 9. The reactor system of any one of the preceding items, wherein the reactor system further comprises an inner tube in heat exchange relationship with the structural catalyst but electrically insulated from the structural catalyst, the inner tube adapted to withdraw product gas from the structural catalyst such that product gas flowing through the inner tube is in heat exchange relationship with gas flowing over the structural catalyst.

[0155] 10. The reactor system of any one of the preceding items, wherein the connection between the structural catalyst and the at least two conductors is a mechanical connection, a welded connection, a brazed connection, or a combination thereof.

[0156] 11. The reactor system of any one of the preceding items, wherein the conductive material comprises a 3D printed or extruded and sintered macrostructure, the macrostructure supporting a ceramic coating, and the ceramic coating supporting a catalytically active material.

[0157] 12. The reactor system of any one of the preceding claims, wherein the structural catalyst comprises an array of macrostructures electrically connected to each other.

[0158] 13. A reactor system according to any one of the preceding claims, wherein the structural catalyst has an electrically insulating component arranged to make the length of the primary current path between the at least two conductors longer than a maximum dimension of the structural catalyst.

[0159] 14. A reactor system according to any one of the preceding items, wherein the structural catalyst has at least one electrically insulating component arranged to direct current through the structural catalyst such that the current density vector of the main current path has a non-zero component value parallel to the length of the structural catalyst for at least 70% of the length of the structural catalyst.

[0160] 15. The reactor system of any one of the preceding items, wherein the macrostructure has a plurality of parallel channels, a plurality of non-parallel channels, and / or a plurality of labyrinth-like channels.

[0161] 16. The reactor system of any one of the preceding items, wherein the reactor system further comprises a third catalyst material in the form of catalyst pellets, extrudates or granules loaded into the channels of the macrostructure.

[0162] 17. The reactor system of any one of the preceding claims, wherein the reactor system further comprises a bed of a fourth catalytic material downstream of the structural catalyst within the pressure shell.

[0163] 18. The material of the macrostructure is heated to 500-50,000 W / m by resistive heating of the material. 2 Item 11. A reactor system according to any one of the preceding items, wherein the material is selected as a material arranged to generate a heat flux of.

[0164] 19. A reactor system according to any one of the preceding items, wherein the structural catalyst comprises a first portion arranged to generate a first heat flux and a second portion arranged to generate a second heat flux, the first heat flux being lower than the second heat flux, and the first portion being upstream of the second portion.

[0165] 20. The reactor system of any one of the preceding items, wherein the structure catalyst comprises a third portion arranged to generate a third heat flux, the third heat flux being lower than the first heat flux and / or the second heat flux, and the third portion is downstream of the first portion and / or the second portion.

[0166] 21. A reactor system according to any one of the preceding items, wherein the reactor system further comprises a control system arranged to control the power supply to ensure that the temperature of the gas leaving the pressure shell is within a predetermined range and / or to ensure that the conversion of the feed gas is within a predetermined range.

[0167] 22. A reactor system according to any one of the preceding items, wherein the ratio of the area-equivalent diameter of a horizontal cross section passing through the structural catalyst to the height of the structural catalyst is in the range of 0.1 to 2.0.

[0168] 23. The reactor system according to any one of the preceding items, wherein the height of the reactor system is from 0.5 to 7 m, more preferably from 0.5 to 3 m.

[0169] 24. The reactor system of any one of the preceding items, wherein the alkane is methane, the catalyst is a BMA catalyst, and the product stream comprises hydrogen cyanide.

[0170] 25. A method for reacting a feed gas comprising an alkane and ammonia into hydrogen cyanide and / or a nitrile in the presence of a catalyst, comprising: a reactor system including a pressure shell housing a structural catalyst arranged to catalyze said endothermic reaction of the feed gas, said structural catalyst comprising a macrostructure of an electrically conductive material, said macrostructure supporting a ceramic coating, said ceramic coating supporting a catalytically active material; said reactor system including thermal insulation between said structural catalyst and said pressure shell; The method includes the steps of: - pressurizing said supply gas - supplying the pressurized feed gas to the pressure shell through an inlet arranged such that the feed gas enters the structural catalyst at a first end of the structural catalyst, reacting the feed gas on the structural catalyst, discharging a product gas from the pressure shell, and the product gas exiting the structural catalyst at a second end of the structural catalyst; - providing electrical power via electrical conductors connecting a power source disposed outside the pressure shell to the structural catalyst, allowing electrical current to flow through the macrostructure, thereby heating at least a portion of the structural catalyst to a temperature of at least 500°C, the at least two conductors being connected to the structural catalyst at a location on the structural catalyst closer to the first end of the structural catalyst than the second end of the structural catalyst, and the structural catalyst being configured to pass electrical current from one conductor substantially to the second end of the structural catalyst and back to the second of the at least two conductors, thereby heating at least a portion of the structural catalyst to a temperature sufficient for the feed gas to perform a BMA reaction on the structural catalyst; - Venting the product gas comprising hydrogen cyanide and / or nitriles from the reactor system.

[0171] 26. The method according to claim 25, wherein the feed gas is pressurized to a pressure between 2 and 30 bar.

[0172] 27. The method according to claim 25, wherein the feed gas is pressurized to a pressure between 30 and 200 bar.

[0173] 28. The method according to any one of items 25 to 27, wherein at least a portion of the structure catalyst is heated to a temperature of at least 700°C, preferably at least 900°C, more preferably at least 1000°C.

[0174] 29. The method of any one of items 25-28, further comprising the step of flowing a cooling gas through an inlet through the pressure shell to cause the cooling gas to flow over at least one conductor.

[0175] 30. The method of any one of items 25 to 29, wherein the alkane is methane, the catalyst is a BMA catalyst, and the product stream comprises hydrogen cyanide.

[0176] 31. The method of claim 30, further comprising the step of feeding the product stream containing hydrogen cyanide to an upgrading unit and separating it into an upgraded hydrogen cyanide stream and an off-gas stream.

[0177] 32. The method of claim 31, wherein the upgrading unit is arranged such that the off-gas stream is recycled and mixed with the feed gas supply before passing over the structured catalyst.

[0178] 33. The method according to item 31 or 32, further comprising the step of supplying the upgraded hydrogen cyanide stream from the upgrading unit to a downstream plant for HCN conversion to an upgraded product, the production of HCN corresponding to the consumption of HCN in the downstream plant.

[0179] 34. A method for rapidly switching a metal-catalyzed reaction of a feed gas containing an alkane and ammonia from a first steady-state reaction condition (A) to a second steady-state reaction condition (B) or vice versa in a reactor system according to any one of the above items 1 to 24; the method comprises the steps of: Under the first steady-state reaction condition (A), - supplying the feed gas to the reactor system at a first total flow rate; and - providing a first electrical power through an electrical conductor connecting a power source disposed outside the pressure shell to the structural catalyst, thereby causing a first electrical current to flow through the electrically conductive material; whereby at least a portion of the structured catalyst is heated to a first temperature at which the feed gas is converted over the structured catalyst under the first steady-state reaction conditions (A) into a first product gas mixture; and discharging the first product gas from the reactor system. And, under the second steady-state reaction condition (B), - supplying the feed gas to the reactor system at a second total flow rate; and - providing a second electrical power through electrical conductor(s) connecting a power source disposed outside the pressure shell to the structural catalyst, thereby causing a second electrical current to flow through the conductive material; whereby at least a portion of the structured catalyst is heated to a second temperature; at which temperature the feed gas is converted over the structured catalyst under the second steady-state reaction conditions (B) into a second product gas mixture; and discharging the second product gas from the reactor system. Here, the second power is greater than the first power and / or the second total flow rate is greater than the first total flow rate.

[0180] 35. The method of claim 34, wherein the at least two conductors are connected to the structural catalyst at a location on the structural catalyst closer to the first end of the structural catalyst than the second end of the structural catalyst, and the structural catalyst is constructed to pass electrical current from one conductor substantially to the second end of the structural catalyst and back to the second of the at least two conductors.

[0181] 36. The method according to any one of items 34 to 35, wherein the ratio (A:B) of total gas supply flow rates under the first reaction condition A and the second reaction condition B is at least 1:10.

[0182] 37. The method according to any one of items 34 to 36, wherein the product gas outlet temperature from the structure catalyst under reaction condition B is 50°C to 800°C higher, for example, 100°C to 500°C higher, preferably 150°C to 400°C higher, than the product gas outlet temperature from the structure catalyst under reaction condition A.

[0183] 38. The method according to any one of items 34 to 37, wherein switching between reaction conditions A and B comprises gradually changing the total gas supply flow rate from the first total flow rate to the second total flow rate and simultaneously gradually changing the applied potential on the conductive material from the first power to the second power.

[0184] 39. The method according to any one of items 34 to 38, wherein the product gas outlet temperature from the structure catalyst under reaction condition B is no more than 50° C. higher than the product gas outlet temperature from the structure catalyst under reaction condition A.

[0185] 40. The method of any one of items 34 to 39, wherein a proportional-integral-derivative (PID) controller controls the potential based on a feedback reading of a process value of the product gas outlet temperature from the structure catalyst.

[0186] 41. The method according to any one of items 34 to 40, wherein the product gas outlet temperature from the structure catalyst is measured at the surface immediately below or at the most downstream surface of the structure catalyst.

[0187] 42. The method according to any one of items 34 to 41, wherein the switching between reaction conditions A and B is carried out over a period of less than 3 hours, such as less than 2 hours, for example less than 60 minutes, preferably less than 30 minutes, further preferably less than 15 minutes.

[0188] 43. The method according to any one of items 34 to 42, wherein switching between reaction conditions A and B includes supplying a second power to the structure catalyst.

[0189] 44. The method according to any one of items 34 to 43, wherein the switching between reaction conditions A and B includes a transition state between the reaction conditions A and B; the transition state includes a first period during which power is turned off, followed by a second period during which the second power of condition B is supplied to the structure catalyst.

[0190] 45. The method according to any one of items 34 to 44, wherein the switching between reaction conditions A and B includes a transition state between reaction conditions A and B; the transition state includes a first period during which a third power is supplied to the structure catalyst, followed by a second period during which a second power of condition B is supplied to the structure catalyst, and the third power is greater than the second power. The present invention further includes the following items. [Item 1] 1. A reactor system for carrying out a reaction of a feed gas comprising an alkane and ammonia to hydrogen cyanide and / or a nitrile in the presence of a catalyst, comprising: - providing a feed gas comprising an alkane and ammonia; - a structured catalyst arranged to catalyze a reaction of said feed gas; wherein said structured catalyst comprises a macrostructure of an electrically conductive material, said macrostructure supporting a ceramic coating, said ceramic coating supporting a catalytically active material; a pressure shell housing the structural catalyst; wherein the pressure shell comprises an inlet for admitting the feed gas and an outlet for discharging a product gas, the inlet being positioned such that the feed gas enters the structural catalyst at a first end thereof and the product gas exits the structural catalyst at a second end thereof; - an insulating layer between the structural catalyst and the pressure shell; - at least two conductors electrically connected to the structural catalyst and a power source disposed outside the pressure shell; wherein the power source is dimensioned to heat at least a portion of the structural catalyst to a temperature of at least 500°C by passing an electric current through the macrostructure, and wherein the at least two conductors are connected to the structural catalyst at a location on the structural catalyst closer to the first end of the structural catalyst than to the second end of the structural catalyst, and the structural catalyst is configured to pass an electric current from one conductor to the second end of the structural catalyst and back to the second conductor of the at least two conductors. - an outlet for the product stream containing hydrogen cyanide and / or nitriles The reactor system comprising: [Item 2] Item 2. The reactor system of item 1, wherein the power source is dimensioned to heat at least a portion of the structure catalyst to a temperature of at least 700°C, preferably at least 900°C, and more preferably at least 1000°C. [Item 3] The feed gas further comprises H 2 、N 2 3. The reactor system according to item 1 or 2, comprising: [Item 4] 4. The reactor system according to any one of items 1 to 3, wherein the pressure shell has a design pressure between 2 and 30 bar. [Item 5] A method for reacting a feed gas comprising alkanes and ammonia into hydrogen cyanide and / or nitriles in the presence of a catalyst, the method comprising: a reactor system including a pressure shell containing a structural catalyst arranged to catalyze said endothermic reaction of the feed gas, the structural catalyst including a macrostructure of an electrically conductive material, the macrostructure supporting a ceramic coating, the ceramic coating supporting a catalytically active material; the reactor system including thermal insulation between the structural catalyst and the pressure shell; - pressurizing the supply gas; - supplying the pressurized feed gas to the pressure shell through an inlet arranged such that the feed gas enters the structural catalyst at a first end of the structural catalyst, reacting the feed gas on the structural catalyst, discharging a product gas from the pressure shell, and the product gas exiting the structural catalyst at a second end of the structural catalyst; - providing electrical power via a plurality of electrical conductors connecting a power source disposed outside the pressure shell to the structural catalyst, allowing electrical current to flow through the macrostructure, thereby heating at least a portion of the structural catalyst to a temperature of at least 500°C, the at least two conductors being connected to the structural catalyst at a location on the structural catalyst closer to the first end of the structural catalyst than the second end of the structural catalyst, and the structural catalyst being configured to allow electrical current to flow from one conductor substantially to the second end of the structural catalyst and back to a second of the at least two conductors, thereby heating at least a portion of the structural catalyst to a temperature sufficient for the feed gas to carry out a BMA reaction on the structural catalyst; - exhausting product gas comprising hydrogen cyanide and / or nitriles from the reactor system. [Item 6] 6. The method of claim 5, wherein the alkane is methane, the catalyst is a BMA catalyst, and the product stream comprises hydrogen cyanide. [Item 7] 7. The method of claim 6, further comprising the step of feeding the product stream comprising hydrogen cyanide to an upgrading unit and separating it into an upgraded hydrogen cyanide stream and an off-gas stream. [Item 8] 8. The method of claim 7, wherein the upgrading unit is arranged such that the off-gas stream is recycled and mixed with the feed gas supply before passing over the structured catalyst. [Item 9] 9. The method according to claim 7 or 8, further comprising the step of feeding the upgraded hydrogen cyanide stream from the upgrading unit to a downstream plant for HCN conversion to an upgraded product, the production of HCN corresponding to the consumption of HCN in the downstream plant. [Item 10] 25. A method for rapidly switching a metal-catalyzed reaction of a feed gas containing an alkane and ammonia from a first steady-state reaction condition (A) to a second steady-state reaction condition (B) or vice versa in the reactor system according to any one of items 1 to 24; Under the first steady-state reaction condition (A), - supplying the feed gas to the reactor system at a first total flow rate; and - providing a first electrical power through an electrical conductor connecting a power source disposed outside the pressure shell to the structural catalyst, thereby causing a first electrical current to flow through the electrically conductive material; whereby at least a portion of the structured catalyst is heated to a first temperature at which the feed gas is converted over the structured catalyst under the first steady-state reaction conditions (A) into a first product gas mixture; and discharging the first product gas from the reactor system. And, under the second steady-state reaction condition (B), - supplying the feed gas to the reactor system at a second total flow rate; and - providing a second electrical power through an electrical conductor connecting a power source disposed outside the pressure shell to the structural catalyst, thereby causing a second electrical current to flow through the conductive material; whereby at least a portion of the structured catalyst is heated to a second temperature; at which temperature the feed gas is converted over the structured catalyst under the second steady-state reaction conditions (B) into a second product gas mixture; and discharging the second product gas from the reactor system; wherein the second power is greater than the first power and / or the second total flow rate is greater than the first total flow rate.

Claims

1. 1. A reactor system for carrying out a BMA reaction from a feed gas comprising alkanes and ammonia to hydrogen cyanide and / or nitriles in the presence of a catalyst, comprising: - supplying a feed gas comprising an alkane and ammonia; - a structured catalyst arranged to catalyze a reaction of said feed gas; wherein said structured catalyst comprises a macrostructure of an electrically conductive material, said macrostructure supporting a ceramic coating, said ceramic coating supporting a catalytically active material; a pressure shell housing the structural catalyst; wherein the pressure shell comprises an inlet for admitting the feed gas and an outlet for discharging a product gas, the inlet being positioned such that the feed gas enters the structural catalyst at a first end thereof and the product gas exits the structural catalyst at a second end thereof; - a thermal insulation layer between the structural catalyst and the pressure shell; at least two conductors electrically connected to the structural catalyst and a power source disposed outside the pressure shell; wherein the power source is sized to heat at least a portion of the structural catalyst to a temperature of at least 500° C. by passing an electric current through the macrostructure, and wherein the at least two conductors are connected to the structural catalyst at a location on the structural catalyst closer to the first end of the structural catalyst than to the second end of the structural catalyst, and wherein the structural catalyst is configured to pass an electric current from one conductor to the second end of the structural catalyst and back to the second conductor of the at least two conductors. - an outlet for the product stream containing hydrogen cyanide and / or nitriles The reactor system comprising:

2. 10. The reactor system of claim 1, wherein said power source is sized to heat at least a portion of said structure catalyst to a temperature of at least 700°C.

3. The feed gas further comprises H ２ , N ２ 3. The reactor system of claim 1 or 2, comprising:

4. The reactor system according to any one of claims 1 to 3, wherein the pressure shell has a design pressure between 2 and 30 bar.

5. A method for reacting a feed gas comprising alkanes and ammonia into hydrogen cyanide and / or nitriles in the presence of a catalyst, the method comprising: a reactor system including a pressure shell containing a structural catalyst arranged to catalyze an endothermic reaction of the feed gas, the structural catalyst including a macrostructure of an electrically conductive material, the macrostructure supporting a ceramic coating, the ceramic coating supporting a catalytically active material; the reactor system including thermal insulation between the structural catalyst and the pressure shell; - pressurizing the supply gas, - supplying the pressurized feed gas to the pressure shell through an inlet arranged such that the feed gas enters the structural catalyst at a first end of the structural catalyst, reacting the feed gas on the structural catalyst, discharging a product gas from the pressure shell, and the product gas exiting the structural catalyst at a second end of the structural catalyst; - providing electrical power via a plurality of electrical conductors connecting a power source disposed outside the pressure shell to the structural catalyst, allowing electrical current to flow through the macrostructure, thereby heating at least a portion of the structural catalyst to a temperature of at least 500°C, at least two conductors being connected to the structural catalyst at a location on the structural catalyst closer to the first end of the structural catalyst than the second end of the structural catalyst, and the structural catalyst being configured to pass electrical current from one conductor substantially to the second end of the structural catalyst and back to a second of the at least two conductors, thereby heating at least a portion of the structural catalyst to a temperature sufficient for the feed gas to carry out a BMA reaction on the structural catalyst; - discharging product gases comprising hydrogen cyanide and / or nitriles from the reactor system.

6. 6. The method of claim 5, wherein the alkane is methane, the catalyst is a BMA catalyst, and the product stream comprises hydrogen cyanide.

7. 7. The method of claim 6, further comprising the step of feeding the product stream comprising hydrogen cyanide to an upgrading unit and separating it into an upgraded hydrogen cyanide stream and an off-gas stream.

8. 8. The method of claim 7, wherein the upgrading unit is configured such that the off-gas stream is recycled and mixed with the feed gas supply prior to passing over the structured catalyst.

9. 9. The method according to claim 7 or 8, further comprising the step of supplying the upgraded hydrogen cyanide stream from the upgrading unit to a downstream plant for HCN conversion to an upgraded product, the production of HCN corresponding to the consumption of HCN in the downstream plant.

10. A method for rapidly switching a metal-catalyzed BMA reaction of a feed gas comprising an alkane and ammonia from a first steady-state reaction condition (A) to a second steady-state reaction condition (B) or vice versa in a reactor system according to any one of claims 1 to 4, comprising: Under the first steady-state reaction condition (A), - supplying the feed gas to the reactor system at a first total flow rate; and - providing a first electrical power through an electrical conductor connecting a power source located outside the pressure shell to the structural catalyst, thereby causing a first electrical current to flow through the electrically conductive material; whereby at least a portion of the structural catalyst is heated to a first temperature at which the feed gas is converted over the structural catalyst under the first steady-state reaction conditions (A) into a first product gas mixture; and discharging the first product gas from the reactor system. And, under the second steady-state reaction condition (B), - supplying the feed gas to the reactor system at a second total flow rate; and - providing a second electrical power through an electrical conductor connecting a power source located outside the pressure shell to the structural catalyst, thereby causing a second electrical current to flow through the conductive material; whereby at least a portion of the structural catalyst is heated to a second temperature; at this temperature, the feed gas is converted over the structural catalyst under the second steady-state reaction conditions (B) into a second product gas mixture; and exhausting the second product gas from the reactor system; wherein the second power is greater than the first power and / or the second total flow rate is greater than the first total flow rate.

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