Catalytically active or activatable mixtures with shaped catalyst bodies and electrically conductive bodies for use in chemical reactors with direct resistance heating

Abstract

This invention relates to a catalytically active or activatable mixture for use in a chemical reactor, comprising: (i) a shaped catalyst body containing a catalytically active or activatable material, and (ii) a conductor, wherein the shaped catalyst body has a characteristic diameter d. cat With the diameter d of these conductors con The ratio between (d) cat / d con The value is in the range of 1.5 to 3, and these shaped catalyst bodies have a characteristic diameter d in the range of 1 mm to 50 mm. cat Furthermore, the diameter of the unformed conductor is the average diameter determined by sieving according to DIN 66165, and the characteristic diameters of the formed catalyst body and the formed conductor are defined as the diameter d of the circumscribed sphere surrounding the formed body. css The sphericity Ψ of the convex hull of the molded body ch The product of the two. The invention further relates to a method for preparing the catalytically active or activatable mixture, the use of the catalytically active or activatable mixture in a chemical reactor as part of or as a directly electrically heated catalyst bed, and a chemical reactor for carrying out a chemical reaction, the chemical reactor containing or comprising the catalytically active or activatable mixture. The invention further relates to a method for carrying out a chemical reaction catalyzed by a shaped catalyst body of the catalytically active or activatable mixture.

Description

[0001] This invention relates to a catalytically active or activatable mixture for use in a chemical reactor, comprising...

[0002] i) A molded catalyst body containing catalytically active or activatable materials, and

[0003] ii) Conductors,

[0004] The characteristic diameter d of the shaped catalyst body cat With the diameter d of the conductor con The ratio between (d) cat / d con () in the range of 1.5 to 3.

[0005] The present invention further relates to a method for preparing the catalytically active or activatable mixture, the use of the catalytically active or activatable mixture as part of or as a directly electrically heated catalyst bed in a chemical reactor, and a chemical reactor for carrying out a chemical reaction comprising or composed of the catalytically active or activatable mixture. The present invention further relates to a method for carrying out a chemical reaction catalyzed by a shaped catalyst body of the catalytically active or activatable mixture.

[0006] Highly endothermic reactions are typically at the beginning of the chemical industry's value creation chain, such as in the cracking of mineral oil fractions, reforming of natural gas or naphtha, reverse water-gas shift reactions, dehydrogenation of propane, dehydrogenation and aromatization of methane to benzene, or pyrolysis of hydrocarbons. To achieve industrially and economically beneficial yields, temperatures between 500°C and 1700°C are required. This is primarily due to the thermodynamic limitations of equilibrium conversion. Most of these highly endothermic reactions are heated by burning fossil-based fuels such as natural gas, heating oil, or other fossil-based fuel gases (including fossil-based waste gases generated as byproducts in the corresponding processes).

[0007] Given the increasing severity of climate change and the chemical industry's commitment to reducing its carbon footprint, it is necessary to replace the burning of fossil-based fuels to generate heat in chemical production with more environmentally friendly decarbonized heat sources, particularly heat generated by electricity (which is obtained from renewable energy sources such as sunlight, wind, water movement, or geothermal heat).

[0008] Electrically heated reactors for carrying out highly endothermic reactions were described more than half a century ago.

[0009] U.S. Patent No. 2,982,622 describes the thermal integration pyrolysis of hydrocarbons in a moving bed composed of an inert material. The required temperature of 1200°C for pyrolysis is obtained by means of electric heating. The heat is generated by the ohmic losses of the current passing through the carbon particle bed, which is heated in the process. No catalyst is required in the described pyrolysis.

[0010] Many large-scale chemical reactions in the chemical industry, especially endothermic reactions, are typically carried out in the presence of catalysts. Recently, the concept of electric heating has also been reported for these endothermic reactions in the presence of catalytically active compounds, enabling the use of heating devices that replace fossil-based fuels.

[0011] DE 10 2013 226 126 describes a method and arrangement for externally heated methane reforming with physical energy recovery, wherein the syngas, consisting of molecular hydrogen and carbon monoxide, is produced from methane and steam and / or carbon dioxide with high efficiency and low energy cost. The starting materials, methane and carbon dioxide, are fed into a fixed-bed reactor consisting of conductive and catalytic particles, which are electrically heated to a temperature of approximately 1000 K. The reactant gases are converted in the fixed bed, and the resulting syngas is heated and expanded. DE 10 2013 226 126 further discloses in paragraph

[0052] that the average size of the conductive particles is 2 to 10 times, preferably 4 times, the average size of the catalyst particles, while the catalytically active particles have an average size of 1 to 50 mm, preferably 5 to 10 mm.

[0012] YR Lu, P. Nikrityuk, Applied Energy, 228, 2018, 593-607 discloses a fixed-bed reactor for endothermic steam methane reforming (SMR) or dry methane reforming (DRM), wherein the fixed bed consists of conductive particles made of nickel with a radius of 5 mm and catalytic particles, for example made of Al2O3, exhibiting a radius of 2 mm to 5 mm.

[0013] WO2017 / 072057 A1 discloses a reactor system for alkane dehydrogenation. The reactor system includes reactor units arranged to contain a catalytic mixture comprising catalyst particles and a ferromagnetic material. The reactor system also includes an induction coil arranged to be powered by an alternating current source and positioned to generate an alternating magnetic field within the reactor unit when powered. This arrangement heats the catalytic mixture to the desired reaction temperature using the alternating magnetic field.

[0014] WO2022 / 023355 A1 discloses a method for endothermic steam reforming of hydrocarbons, the method comprising the steps of: providing a fluidized bed reactor comprising at least two electrodes and a bed containing particles, wherein the particles are fluidized to obtain a fluidized bed; heating the fluidized bed to a temperature ranging from 500°C to 1200°C by passing an electric current through the fluidized bed to carry out an endothermic reaction. The fluidized bed comprises particles of conductive particles and particles of a catalytic composition. The fluidized bed is heated by passing an electric current through the fluidized bed. The particles of the fluidized bed have an average particle size preferably ranging from 30 to 150 µm, as determined by sieving according to ASTM D4513-11.

[0015] Commercially available catalysts for large-scale processes in most chemical industries are typically supplied in the form of shaped catalyst bodies. These shaped catalyst bodies can be used for a wide variety of reaction types. For reactions occurring in the gas phase, shaped catalyst bodies are used in fixed-bed or moving-bed reactors. Shaped catalyst bodies are generally not used in fluidized-bed reactors due to their size and associated weight. In the case of commercially available shaped catalyst bodies, the maximum size is typically in the range of 1 mm to 100 mm.

[0016] Since many commercially available catalysts in the form of shaped catalyst bodies do not have sufficient electrical conductivity to convert electrical energy into thermal energy, mixing a conductor for generating heat with the catalyst body, as described above in DE 10 2013 226 126 or by YR Lu, P. Nikrityuk in Applied Energy, provides an opportunity to form an electrically heated catalyst bed.

[0017] Based on the prior art, the object of the present invention is to provide a catalytically active mixture comprising a well-known, commercially available shaped catalyst body, wherein the mixture is electrically heatable, preferably at high voltage and low ampere number, and wherein the mixture exhibits high catalytic activity, improved space-time yield, and provides the desired homogeneity and stability under reaction conditions.

[0018] This objective is achieved by a catalytically active or activatable mixture for use in a chemical reactor, the catalytically active or activatable mixture comprising

[0019] i) A molded catalyst body containing catalytically active or activatable materials, and

[0020] ii) Conductors,

[0021] The characteristic diameter d of the shaped catalyst body cat With the diameter d of the conductor con The ratio between (d)cat / d con ) in the range of 1.5 to 3, and

[0022] The shaped catalyst body has a characteristic diameter d in the range of 1 mm to 50 mm. cat ,and

[0023] The diameter of the unformed conductor is the average diameter determined by sieving according to DIN 66165, and

[0024] The characteristic diameters of the shaped catalyst body and the shaped conductor are defined as the diameter d of the outer sphere surrounding the shaped body. css Ψ of the convex hull of the molded body ch The product of.

[0025] In the context of this invention, the term catalytically active or activatable mixture means a mixture comprising a material that is already catalytically active before being brought into contact with the starting material of the contemplated chemical reaction, or a material that is converted into a catalytically active material before being brought into contact with the starting material of the contemplated chemical reaction for the first time, or during any of the first contacts with the starting material of the contemplated chemical reaction.

[0026] The catalytically active or activatable mixture of the present invention is applied in a chemical reactor, meaning it is designed for use in a chemical reactor. Chemical reactors for various chemical reactions, particularly for the aforementioned endothermic reactions, are known to those skilled in the art. The catalytically active or activatable mixture of the present invention is preferably suitable for use in a moving bed reactor or a fixed bed reactor, more preferably in a fixed bed reactor.

[0027] In one embodiment of the invention, the catalytically active or activatable mixture of the invention is characterized in that the chemical reactor is a moving bed reactor or a fixed bed reactor, preferably a fixed bed reactor.

[0028] In a moving bed reactor, fresh solids can be fed from the top, while the gas stream is fed from the bottom. These solid particles move slowly down the reactor and are removed from the bottom of the bed.

[0029] Fixed-bed reactors are a major type of catalytic reactor used for large-scale chemical synthesis. This method is characterized by the reaction of different gaseous chemical substances on the surface of a catalyst placed at a fixed location inside the reactor.

[0030] The catalytically active or activatable mixture of the present invention comprises a shaped catalyst body (hereinafter also referred to as catalyst body) containing catalytically active or activatable material as a first component (i) and an electrically conductive body (hereinafter also referred to as conductor body) as a second component (ii).

[0031] The catalytically active or activatable mixture of the present invention may contain additional components besides the catalyst body and the conductor. These additional components, although neither catalytically active nor activatable nor conductive, may improve another desired characteristic of the mixture, such as its mechanical or chemical stability. Considering the recycling of the catalytically active or activatable mixture after prolonged use in a chemical reactor, it is advantageous for the mixture to consist of as few components as possible. The mixture preferably consists of at least 90%, preferably at least 95%, and particularly at least 99% by weight, preferably only a molded catalyst body containing catalytically active or activatable material and a conductor. Although the molded catalyst bodies may differ from each other in at least one characteristic (e.g., the amount or nature of the catalytically active material in two considered molded catalyst bodies), it is preferred that the catalyst bodies be identical in the amount and nature of the catalytically active material to simplify any future recycling. For the same reason, the conductor (which may contain different conductor materials) is preferably identical in its chemical composition.

[0032] In another embodiment of the invention, the catalytically active or activatable mixture of the invention is characterized in that the sum of the mass fraction of the shaped catalyst body containing the catalytically active or activatable material and the mass fraction of the conductor is in the range of 0.9 to 1, preferably in the range of 0.95 to 1, and particularly in the range of 0.99 to 1.

[0033] In the context of this invention, the term "body" refers to a three-dimensional geometric object whose minimum size is in the range of mm and can be observed with the naked eye. The minimum size preferably begins at about 0.2 mm, more preferably about 0.5 mm, even more preferably about 1 mm, and particularly about 2 mm. Therefore, particles of coarse powder (such as semolina) can already be referred to as bodies in the sense of this invention. Another example of the term "body" in the sense of this invention is crushed stone or gravel with a particle size in the range of 2 mm to 32 mm. Gravel does not have "sharp edges," and stones are round and have smooth surfaces, while crushed stone (so-called stone chips) is quite angular and has a fairly rough surface.

[0034] In the context of this invention, the term "molded body" refers to a body produced by a molding or shaping process. The geometry of a molded body is very similar or identical in at least two dimensions. Geometry formed by extrusion is very similar or nearly identical in two dimensions (cross-sectional area), but variable in their length. Geometry formed by sheeting, casting, or 3D printing is very similar or nearly identical in all three dimensions.

[0035] The terms "uniform" or "non-uniform" are used in this specification to describe a group of objects in terms of one or more characteristics, such as shape, aspect ratio, size, or mass. A group of objects is said to be uniform in terms of the same shape, aspect ratio, size, or mass.

[0036] Although a group of bodies with coarse powder, gravel, or crushed stone exhibits similar particle sizes, all particles in the example differ in shape, meaning they possess non-uniform geometry. Bodies with non-uniform geometry are typically formed by pulverizing solid materials, while bodies with uniform geometry are typically produced using molding manufacturing methods such as extrusion, tableting, casting, or 3D printing. Bodies with non-uniform geometry can also be formed by mixing at least two groups of bodies with uniform geometry.

[0037] In the context of this invention, a molded body with a uniform geometry is a body that is very similar or identical in shape and at least two dimensions, such as a tablet, which has a uniform shape in three dimensions. Another example of a molded body with a uniform geometry in the context of this invention is an extruder having a uniform cross-section, wherein length differences are generally small and can be minimized. 3D printed bodies are another example of molded bodies with a uniform geometry.

[0038] The catalytically active or activatable mixtures of the present invention may comprise different types of molded catalyst bodies, such as tablets and extrusions of different sizes but having the same chemical composition, or two extrusions exhibiting two different cross-sectional areas. In both cases, the molded catalyst bodies containing catalytically active or activatable materials have a non-uniform geometry. The catalytically active or activatable mixtures of the present invention may also comprise different types of molded catalyst bodies containing different amounts or types of catalytically active or activatable materials, but exhibiting the same or different geometries.

[0039] A shaped catalyst body or a precursor thereof (which may subsequently be contacted with a catalytically active or activatable material to form a shaped catalyst body) can be prepared by a variety of methods known to those skilled in the art, thereby obtaining a shaped catalyst body having a uniform or non-uniform geometry.

[0040] Preferably, the molded catalyst body used in this invention is prepared by only one of the above-described molding manufacturing methods, thereby obtaining a body that is virtually identical when inspected by the naked eye. This means that the molded catalyst body containing catalytically active or activatable materials preferably has a uniform geometric configuration.

[0041] In one embodiment of the invention, the catalytically active or activatable mixture of the invention is characterized in that the molded catalyst body containing the catalytically active or activatable material has a uniform geometric configuration.

[0042] The shaped catalyst body with a uniform geometric configuration can exhibit a variety of geometric shapes, preferably with a characteristic diameter ranging from 3 to 15 mm, and preferably extruded, pellet, annular, cylindrical, star-shaped, wagon wheel-shaped, spherical, extruded, trilobal or tetralobal, with pellet, spherical or extruded being the most preferred.

[0043] In another embodiment of the invention, the catalytically active or activatable mixture of the invention is characterized in that the shaped catalyst body has a shape selected from the group consisting of: pellet, annular, cylindrical, star-shaped, wheel-shaped, spherical, extruded, trilobal, and tetralobal, preferably pellet, spherical, and extruded.

[0044] The specific surface area of ​​the molded catalyst body can vary over a wide range depending on the production method and the materials and additives used. Preferably, the specific surface area of ​​the molded catalyst body is determined using the Brunauer-Emmett-Teller (N2-BET) adsorption method and ranges from 0.1 to 500 m². 2 Within the range of / g, more preferably within 10 to 300 m 2 Within the range of / g.

[0045] In another embodiment of the invention, the catalytically active or activatable mixture of the invention is characterized in that the shaped catalyst body has a density of 0.1 to 500 μm. 2 Within the range of / g (N2-BET), more preferably from 10 to 300 m 2 Specific surface area within the range of / g (N2-BET).

[0046] The aspect ratio of the shaped catalyst body can vary over a wide range, wherein the aspect ratio is defined as the ratio between the maximum dimension and the minimum dimension of the body. Preferably, the shaped catalyst body has an aspect ratio in the range of 1.0 to 10, more preferably in the range of 1 to 5, more preferably in the range of 1 to 4, even more preferably in the range of 1 to 3, and particularly in the range of 1 to 2.

[0047] In another embodiment of the invention, the catalytically active or activatable mixture of the invention is characterized in that the shaped catalyst body has an aspect ratio in the range of 1.0 to 10, preferably in the range of 1 to 5, more preferably in the range of 1 to 4, even more preferably in the range of 1 to 3, and particularly in the range of 1 to 2.

[0048] The conductive material of the mixture of the present invention can also be prepared by a variety of methods known to those skilled in the art, thereby obtaining unformed or formed conductive materials having a uniform or non-uniform geometry, preferably a non-uniform geometry. As mentioned above, materials with a non-uniform geometry are preferably prepared by crushing the corresponding solid material (e.g., by crushing a block of conductive material), while materials with a uniform geometry are generally prepared by means of molding manufacturing methods (e.g., extrusion, compaction by pressing, casting, or 3D printing as described above).

[0049] In one embodiment of the present invention, the catalytically active or activatable mixture of the present invention is characterized in that the conductor has a uniform or non-uniform geometry, preferably the conductor has a non-uniform geometry.

[0050] Conductors with non-uniform geometry have different shapes because they are preferably prepared by crushing blocks of conductive material, but these conductors preferably have similar aspect ratios, diameters or masses.

[0051] In one embodiment of the invention, the catalytically active or activatable mixture of the invention is characterized in that the conductor is a homogeneous or heterogeneous body, preferably a heterogeneous body, and preferably a heterogeneous body having similar aspect ratio, similar diameter, or similar mass.

[0052] When the conductor is a molded body with a uniform geometric configuration, the molded conductor preferably has a shape selected from the group consisting of a pellet, a ring, a cylinder, a star, a wheel, a sphere, an extruded shape, a trefoil shape, and a tetralobed shape, and preferably selected from the group consisting of a pellet, a sphere, and an extruded shape.

[0053] In another embodiment of the invention, the catalytically active or activatable mixture of the invention is characterized in that the conductor is a uniform body having a shape selected from the group consisting of pellets, rings, cylinders, stars, wheels, spheres, extrusions, trefoils, and tetralobes, preferably selected from the group consisting of pellets, spheres, and extrusions.

[0054] The aspect ratio of a conductor (both homogeneous and non-homogeneous) can vary over a wide range, wherein the aspect ratio is defined as described above. Preferably, the conductor has an aspect ratio in the range of 1.0 to 10, more preferably in the range of 1 to 5, more preferably in the range of 1 to 4, even more preferably in the range of 1 to 3, and particularly in the range of 1 to 2.

[0055] In another embodiment of the invention, the catalytically active or activatable mixture of the invention is characterized in that the conductor has an aspect ratio in the range of 1.0 to 10, preferably in the range of 1 to 5, more preferably in the range of 1 to 4, even more preferably in the range of 1 to 3, and particularly in the range of 1 to 2.

[0056] In another embodiment of the invention, the catalytically active or activatable mixture of the invention is characterized in that the shaped catalyst body has an aspect ratio in the range of 1 to 10, preferably in the range of 1 to 5, more preferably in the range of 1 to 4, even more preferably in the range of 1 to 3, particularly in the range of 1 to 2, and the conductor has an aspect ratio in the range of 1 to 10, preferably in the range of 1 to 5, more preferably in the range of 1 to 4, even more preferably in the range of 1 to 3, particularly in the range of 1 to 2.

[0057] The conductors of the catalytically active or activatable mixture of the present invention, having a non-uniform geometry, are characterized by an average diameter, while the conductors of the molded body having a uniform geometry are characterized by a characteristic diameter.

[0058] A shaped catalyst body containing catalytically active or activatable materials and having a uniform geometric configuration is also characterized by a characteristic diameter.

[0059] In the context of this invention, the characteristic “average diameter” of a geometrically non-uniform body, preferably a conductor having a non-uniform geometry, is determined by sieving according to DIN 66165.

[0060] In the context of this invention, the characteristic "characteristic diameter" of a shaped catalyst body or a shaped conductor is defined as the diameter d of the outer sphere surrounding the shaped body. css sphericity Ψ of the convex hull of the molded body ch The product of.

[0061] The aforementioned objective is also achieved by a catalytically active or activatable mixture for use in a chemical reactor, the catalytically active or activatable mixture comprising

[0062] i) A molded catalyst body containing catalytically active or activatable materials, and

[0063] ii) Conductors,

[0064] The characteristic diameter d of the shaped catalyst body cat With the diameter d of the conductor con The ratio between (d) cat / d con ) in the range of 1.5 to 3, and

[0065] The shaped catalyst body has a uniform geometric configuration, and

[0066] The conductor has a non-uniform geometric configuration characterized by its average diameter, or the conductor is a shaped conductor with a uniform geometric configuration characterized by its characteristic diameter.

[0067] The characteristic diameters of the shaped catalyst body and the shaped conductor are defined as the diameter d of the outer sphere surrounding the shaped body. css The sphericity Ψ of the convex hull of the molded body ch The product of, and

[0068] The average diameter of the conductor with a non-uniform geometry is determined by sieving according to DIN 66165.

[0069] For the purposes of this invention, the characteristic diameter of the shaped catalyst body and the average diameter of the conductor are determined by methods known to those skilled in the art. The characteristic diameter of a shaped body with a uniform geometry can be determined by simply measuring the dimensions of the body with calipers or a microscope and performing some calculations as described in the experimental section. In the case of extrudates in the form of shaped bodies with a certain distribution in length, the average length based on mass should be used in the calculations. The average diameter of a body with a non-uniform geometry can be determined by sieving according to DIN 66165.

[0070] The characteristic diameter d is equal to the diameter d of the circumscribed sphere surrounding the shaped body. css Ψ of the convex hull of the molded body ch The product of:

[0071]

[0072] Among them Ψ ch The volume V of the convex hull of the molded body ch Surface area A of the convex hull of the molded body ch function

[0073]

[0074] The characteristic diameter d of the shaped catalyst body used in the catalytically active or activatable mixture of the present invention is... cat The diameter can vary within a wide range. Preferably, the shaped catalyst body, especially the shaped catalyst body with a uniform geometry, has a characteristic diameter d in the range of 1 mm to 50 mm, preferably in the range of 2 mm to 30 mm, and more preferably in the range of 3 mm to 15 mm. cat .

[0075] In one embodiment of the invention, the catalytically active or activatable mixture of the invention is characterized in that the shaped catalyst body has a characteristic diameter d in the range of 1 mm to 50 mm, preferably in the range of 2 mm to 30 mm, and more preferably in the range of 3 mm to 15 mm. cat .

[0076] The diameter of the conductor used in the catalytically active or activatable mixtures of the present invention can also vary within a wide range. In the present invention, the diameter of the conductor is as defined above. Preferably, the conductor having a uniform or non-uniform geometry, preferably the conductor having a non-uniform geometry, has a diameter in the range of 0.2 mm to 67 mm, preferably 0.33 mm to 33 mm, preferably 0.5 mm to 30 mm, more preferably 0.67 mm to 20 mm, particularly in the range of 1 mm to 10 mm, preferably the average diameter.

[0077] Methods for determining the diameter of a conductor, preferably the average diameter of the conductor, are known and have been described above, particularly according to DIN 66165 or alternatively according to ASTM D4513-11, preferably according to DIN 66165 by sieving.

[0078] In one embodiment of the invention, the catalytically active or activatable mixture of the invention is characterized in that the conductor having a uniform or non-uniform geometry, preferably having a non-uniform geometry, has a diameter, preferably an average diameter, in the range of 0.2 mm to 67 mm, preferably 0.33 mm to 33 mm, more preferably in the range of 0.5 mm to 30 mm, more preferably in the range of 0.67 mm to 20 mm, particularly in the range of 1 mm to 10 mm.

[0079] The present invention comprises a catalytically active or activatable mixture of a shaped catalyst body and a conductor, characterized in that the shaped catalyst body has a characteristic diameter d. cat With the diameter d of the conductor conThe ratio between (d) cat / d con () in the range of 1.5 to 3.

[0080] If the ratio d cat / d con If the diameter of the conductor is in the range of 1.5 to 3 and the characteristic diameter of the shaped catalyst body is in the range of 1 mm to 50 mm, then the diameter of the conductor is preferably in the range of 0.33 mm to 33 mm.

[0081] If the ratio d cat / d con In the most preferred range of 1.5 to 3 and the characteristic diameter of the shaped catalyst body is in the preferred range of 2 mm to 30 mm, the diameter of the conductor is in the preferred range of 0.67 mm to 20 mm.

[0082] If the ratio d cat / d con In the preferred range of 1.5 to 3 and the preferred range of the characteristic diameter of the shaped catalyst body is 3 mm to 15 mm, the diameter of the conductor is preferably in the range of 1 mm to 10 mm.

[0083] In one embodiment of the invention, the catalytically active or activatable mixture of the invention is characterized by a characteristic diameter d of the shaped catalyst body. cat With the diameter d of the conductor con The ratio between (d) cat / d con The characteristic diameter of the shaped catalyst body is in the range of 1.5 to 3, the diameter of the conductor is in the range of 1 mm to 50 mm, and the diameter of the conductor is in the range of 0.33 mm to 33 mm.

[0084] In another embodiment of the invention, the catalytically active or activatable mixture of the invention is characterized by a characteristic diameter d of the shaped catalyst body. cat With the diameter d of the conductor con The ratio between (d) cat / d con The characteristic diameter of the shaped catalyst body is in the range of 1.5 to 3, the diameter of the conductor is in the range of 2 mm to 30 mm, and the diameter of the conductor is in the range of 0.67 mm to 20 mm.

[0085] In another embodiment of the invention, the catalytically active or activatable mixture of the invention is characterized by a characteristic diameter d of the shaped catalyst body. cat With the diameter d of the conductor con The ratio between (d) cat / d conThe characteristic diameter of the shaped catalyst body is in the range of 3 mm to 15 mm, and the diameter of the conductor is in the range of 1 mm to 10 mm, within the range of 1.5 to 3.

[0086] Catalytically active or activatable materials, as part of a shaped catalyst body, are known to those skilled in the art for all industrially relevant chemical reactions. Typically, catalytically active or activatable materials comprise compounds selected from the group consisting of transition metals, transition metal oxides, main group metal oxides, rare earth metal oxides, and mixtures thereof.

[0087] The structure and chemical composition of the molded catalyst body containing catalytically active or activatable materials can vary over a wide range depending on the chemical reaction, preferably an endothermic or highly endothermic reaction (which can be catalyzed by the molded catalyst body). The structure and chemical composition of the conductor can also vary over a wide range depending on the temperature range necessary to carry out the desired chemical reaction, preferably one of the aforementioned endothermic reactions. In this invention, the molded catalyst body and the conductor are preferably different in their chemical compositions, and they preferably exhibit different material properties, particularly different resistivity.

[0088] In one embodiment of the present invention, the catalytically active or activatable mixture of the present invention is characterized in that the shaped catalyst body and the conductor have different chemical compositions.

[0089] In another embodiment of the invention, the catalytically active or activatable mixture of the invention is characterized in that the shaped catalyst body and the conductor have different resistivities.

[0090] The bulk resistivity of the shaped catalyst body at 20°C is higher than that of the conductor at 20°C, preferably at least 10 ohms higher. 1 Times, or more preferably at least 10 times higher 2 Times, especially high, at least 10 times higher 3 This means that any significant contribution from the shaped catalyst body to the current required to generate heat is negligible.

[0091] The volume resistivity at 20°C is determined by methods known to those skilled in the art. The resistivity of a body containing or composed of an electrical conductor is determined according to ASTM B193-20. In cases where the body contains or is composed of a carbonaceous material, the resistivity is preferably determined according to ASTM C611-21. In cases where the body contains or is composed of a ceramic material, the resistivity is preferably determined according to ASTM D1829-90.

[0092] The catalytically active or activatable mixture of the present invention, comprising a shaped catalyst body and a conductor, generates heat through ohmic losses when an electric current passes through the mixture. In the mixture, the current flows via the contact points between the conductors, particularly the contact points between the conductors themselves.

[0093] The catalytically active or activatable mixtures of the present invention have a fixed-bed resistivity that can vary over a wide range at 20°C, depending particularly on the volume fraction and bulk resistivity of the conductor. The bed resistivity of the catalytically active or activatable mixtures of the present invention at 20°C is in the range of 10. -4 - 10 2 Ωm, preferably 10 -3 -10 2 Ωm, or even more preferably 10 -3 - 10 1 Within the range of Ωm.

[0094] The resistivity of the catalytically active or activatable mixture of the present invention at 20°C was determined as described in the experimental section of the present invention. The method is similar to that described in ISO 10143:2019.

[0095] In another embodiment of the invention, the catalytically active or activatable mixture of the invention is characterized in that the catalytically active or activatable mixture has a catalytic activity at 20°C for 10... -4 - 10 2 Ωm, preferably 10 -3 - 10 2 Ωm, or even more preferably 10 -3 - 10 1 Fixed bed resistivity in the Ωm range.

[0096] In order to reproducibly achieve the fixed-bed resistivity of the catalytic activity or activatable mixture of the present invention, it is necessary to uniformly distribute the shaped catalyst body and the conductor in each considered volume of the mixture.

[0097] In one embodiment of the invention, the catalytically active or activatable mixture of the invention is characterized in that the shaped catalyst body and the conductor are uniformly distributed in each considered volume of the mixture.

[0098] The bulk resistivity of the conductor in the catalytically active or activatable mixture of the present invention can vary over a wide range at 20°C. Preferably, the bulk resistivity of the conductor at 20°C is lower than the aforementioned value of the fixed-bed resistivity of the catalytically active or activatable mixture of the present invention at 20°C, because the path of current through the bulk mixture is preferably via the contact points between the conductors. The conductor preferably has a resistivity of 10 at 20°C. -8 - 10 -2 Ωm, more preferably 10 -7 -10 -3 Ωm, or even more preferably 10 -7 - 10 -4 Volume resistivity in the Ωm range.

[0099] In another embodiment of the invention, the catalytically active or activatable mixture of the invention is characterized in that the conductor has a conductivity of 10 at 20°C. -8 - 10 -2 Within the Ωm range, preferably within 10 -7 - 10 -3 Within the Ωm range, more preferably within 10 -7 - 10 -4 Volume resistivity in the Ωm range.

[0100] The conductive material contained in the catalytically active or activatable mixture of the present invention is sufficient to achieve the desired bulk resistivity of the conductor at 20°C, and is composed of at least one conductive material. Conductive materials are known to those skilled in the art. The conductive material is preferably selected from the group consisting of: metals, metal alloys, non-metallic resistors, metal carbides, transition metal nitrides, metal borides, metal silicides, metal phosphides, and materials containing at least 60% sp 2 - Carbon in polymorphs of hybrid carbon atoms, superionic conductors, phosphate electrolytes, mixed oxides doped with lower valence cations, mixed sulfides doped with lower valence cations, composite materials containing at least 30% by weight of any of the aforementioned conductive materials, and any mixtures thereof.

[0101] In one embodiment of the invention, the catalytically active or activatable mixture of the invention is characterized in that the conductor comprises or is composed of a conductive material selected from the group consisting of: metals, metal alloys, non-metallic resistive materials, metal carbides, transition metal nitrides, metal borides, metal silicides, metal phosphides, and materials containing at least 60% sp 2- Carbon in polymorphs of hybrid carbon atoms, superionic conductors, phosphate electrolytes, mixed oxides doped with lower valence cations, mixed sulfides doped with lower valence cations, composite materials containing at least 30% by weight of any of the aforementioned conductive materials, and any mixtures thereof.

[0102] The following are typical, but not limiting, examples of the different conductive materials of the types listed above.

[0103] Metals: Ni, Fe, or Cu

[0104] Metal alloys: Ni-Cr, Fe-Ni-Cr, Fe-Ni-Al or mixtures thereof

[0105] Non-metallic resistive materials: SiC or Si-doped SiC

[0106] Metal carbides: Fe2C, MoC or Mo2C

[0107] Transition metal nitrides: ZrN, W₂N, WN, WN₂, VN, TaN, or NbN

[0108] Metal borides: TiB2, HfB2, TaB2, W2B5, Fe2B or LaB6

[0109] Metal silicides: MoSi2, NiSi, Na2Si, Mg2Si, PtSi, TiSi, or WSi2

[0110] Metal phosphides: Cu3P, InP, GaP, Na3P, AlP, Zn3P2 or Ca3P2

[0111] It contains at least 60% sp 2 - Polymorphic carbon with hybridized carbon atoms: activated carbon, such as carbon black, graphite, graphene, petroleum coke, coke, or mixtures thereof.

[0112] Superionic conductor: Li 10 GeP2S 12 Na3Zr2PSi2O 12 or NaAl 11 O 17

[0113] Phosphate electrolytes: LiPO4 or LaPO4

[0114] Mixed oxides doped with lower valence cations: garnet-type structures such as Li7La3Zr2O 12 or a replacement of the ABO3-perovskite structure

[0115] Mixed sulfides doped with lower valence cations: Li₂P₂S₈I or Li₃PS₄ or Li5.55 Ca 0.1 PS 4.75 Cl 1.25

[0116] Preferably, the conductor of the catalytically active or activatable mixture of the present invention comprises or is composed of a conductive material selected from the group consisting of at least 60% sp 2 -Hybridized carbon atoms, preferably 75% to 100% sp 2 - Polymorphs of hybrid carbon atoms, carbon, metals, metal alloys, non-metallic resistive materials, metal carbides, transition metal nitrides, metal borides, metal silicides, metal phosphides, composite materials containing at least 30%, more preferably at least 60%, or even more preferably at least 90% by weight of any of the above-listed conductive materials, and any mixtures thereof.

[0117] More preferably, the conductor of the catalytically active or activatable mixture of the present invention comprises or is composed of a conductive material selected from the group consisting of 75% to 100% sp 2 - Polymorphs of hybrid carbon atoms, such as carbon black, graphite, graphene, petroleum coke, coke or mixtures thereof, metals such as Ni, metal alloys, non-metallic resistive materials such as SiC or Si-doped SiC, and any mixtures thereof.

[0118] In another embodiment of the invention, the catalytically active or activatable mixture of the invention is characterized in that the conductor comprises or is composed of a conductive material selected from the group consisting of 75% to 100% sp 2 - Polymorphs of hybrid carbon atoms, such as carbon black, graphite, graphene, petroleum coke, coke or mixtures thereof, metals such as Ni, metal alloys, non-metallic resistive materials such as SiC or Si-doped SiC, and any mixtures thereof.

[0119] In the catalytically active or activatable mixtures of the present invention, the volume fraction of the catalyst body containing the catalytically active or activatable material and the volume fraction of the conductor can vary over a wide range. In the present invention, volume fraction is defined as the volume of a component divided by the total volume of all components of the mixture before mixing.

[0120] The mixture of the present invention preferably comprises a molded catalyst body containing catalytically active or activatable material in a volume fraction ranging from 0.1 to 0.95, preferably 0.3 to 0.95, more preferably 0.4 to 0.95, and a conductor in a volume fraction ranging from 0.05 to 0.9, preferably 0.05 to 0.7, more preferably 0.05 to 0.6. More preferably, the mixture of the present invention comprises a molded catalyst body containing catalytically active or activatable material in a volume fraction ranging from 0.3 to 0.8, preferably 0.4 to 0.8, more preferably 0.45 to 0.8, and a conductor in a volume fraction ranging from 0.2 to 0.7, preferably 0.2 to 0.6, more preferably 0.2 to 0.55. Even more preferably, the mixture of the present invention comprises a molded catalyst body containing catalytically active or activatable material in a volume fraction ranging from 0.4 to 0.7, preferably 0.45 to 0.7, more preferably 0.5 to 0.7, and a conductor in a volume fraction ranging from 0.3 to 0.6, preferably 0.3 to 0.55, more preferably 0.3 to 0.5.

[0121] In one embodiment of the present invention, the catalytically active or activatable mixture of the present invention is characterized in that the volume fraction of the molded catalyst body containing the catalytically active or activatable material is in the range of 0.4 to 0.95 and the volume fraction of the conductor is in the range of 0.05 to 0.6, preferably the volume fraction of the molded catalyst body is in the range of 0.45 to 0.8 and the volume fraction of the conductor is in the range of 0.2 to 0.55, more preferably the volume fraction of the molded catalyst body is in the range of 0.5 to 0.7 and the volume fraction of the conductor is in the range of 0.3 to 0.5.

[0122] In another embodiment of the invention, the catalytically active or activatable mixture of the invention is characterized in that the volume fraction of the molded catalyst body containing the catalytically active or activatable material is in the range of 0.4 to 0.8 and the volume fraction of the conductor is in the range of 0.2 to 0.6, preferably in the range of 0.45 to 0.8 and the volume fraction of the conductor is in the range of 0.2 to 0.55, more preferably in the range of 0.45 to 0.7 and the volume fraction of the conductor is in the range of 0.3 to 0.55.

[0123] As described above, the catalytically active or activatable mixture of the present invention comprises at least 90% by weight, preferably at least 95% by weight, and particularly at least 99% by weight, preferably consisting only of a shaped catalyst body (component (i)) and a conductor (component (ii)).

[0124] The sum of the volume fraction of component (i) and the volume fraction of component (ii) is preferably in the range of 0.9 to 1, more preferably in the range of 0.95 to 1, and particularly in the range of 0.99 to 1.

[0125] In another embodiment of the invention, the catalytically active or activatable mixture of the invention is characterized by a ratio (d) between the characteristic diameter of the shaped catalyst body and the diameter of the conductor. cat / d con The shaped catalyst body has a characteristic diameter in the range of 3 mm to 15 mm, and the volume fraction of the shaped catalyst body containing catalytically active or activatable material is in the range of 0.5 to 0.7, the volume fraction of the conductor is in the range of 0.3 to 0.5, and the sum of the volume fraction of the shaped catalyst body and the volume fraction of the conductor is in the range of 0.95 to 1.

[0126] In another embodiment of the invention, the catalytically active or activatable mixture of the invention is characterized in that the molded catalyst body containing the catalytically active or activatable material has a uniform geometric configuration, and the conductor has a uniform or heterogeneous geometric configuration, preferably a heterogeneous geometric configuration, and the molded catalyst body has a characteristic diameter d in the range of 2 mm to 30 mm, preferably 3 mm to 15 mm. cat Furthermore, the sum of the volume fraction of the shaped catalyst body and the volume fraction of the conductor is in the range of 0.95 to 1.

[0127] The present invention further provides a method for preparing a catalytically active or activatable mixture as described in the above detailed description, the method comprising at least the following steps.

[0128] (a) Mixing a defined volume of shaped catalyst body with a defined volume of conductive body.

[0129] The description and preferred embodiments of catalytically active or activatable mixtures for use in chemical reactors, their composition and properties (including the properties of the components) correspond to the above description of these characteristics of catalytically active or activatable mixtures.

[0130] Methods for mixing two or more different types of particles or bodies to obtain a homogeneous mixture of the components are known to those skilled in the art. Due to differences in the size, density, or other physical properties of the materials used to construct the different particles or bodies, not all known mixing methods yield a stable, homogeneous mixture of the different particles or bodies.

[0131] The method for preparing the catalytically active or activatable mixture of the present invention for use in a chemical reactor is preferably carried out by adding two volumes of the two components (formed catalyst body and conductor) simultaneously and uniformly to a new container, preferably to the chemical reactor itself, according to their volume ratio, to directly form a heatable catalyst bed.

[0132] In one embodiment of the present invention, the method of the present invention for preparing the catalytically active or activatable mixture of the present invention is characterized in that the mixing of a defined volume of shaped catalyst body and a defined volume of conductor body is accomplished by simultaneously and uniformly adding the two volumes according to their volume ratio into a new container, preferably into a chemical reactor.

[0133] The catalytically active or activatable mixture of the present invention is preferably used in an electrically heated catalyst bed in a chemical reactor. The electrically heated catalyst bed of the chemical reactor (preferably a moving bed reactor or a fixed bed reactor, particularly a fixed bed reactor) comprises or is preferably composed of the catalytically active or activatable mixture. The electrically heated catalyst bed of a moving bed reactor is typically almost identical throughout all sections of the catalyst bed from top to bottom, while the electrically heated catalyst bed of a fixed bed reactor may include regions (layers) of mixtures with different catalytic activities or activatable properties, thereby generating different amounts of heat in different sections of the catalyst bed or (e.g., from bottom to top) altering the number or nature of catalytic reaction centers to optimize the desired reaction (partitioned catalyst bed).

[0134] The present invention further provides the use of the catalytically active or activatable mixture of the present invention in a chemical reactor, preferably in a moving bed reactor or a fixed bed reactor, particularly in a fixed bed reactor, as part of or as a directly electrically heated catalyst bed.

[0135] The present invention further provides a method for carrying out a chemical reaction catalyzed by a shaped catalyst body of a catalytically active or activatable mixture as described in detail above, the method comprising the following steps.

[0136] (b) Establishing a catalyst bed in a chemical reactor comprising or consisting of a catalytically active or activatable mixture as described above, the chemical reactor comprising at least one pair of electrodes through which an electric current can be conducted through the catalyst bed comprising or consisting of the catalytically active or activatable mixture as described above.

[0137] (c) Heating the catalyst bed comprising or consisting of the catalytically active or activatable mixture by applying a voltage to each pair of electrodes, and

[0138] (d) Introducing a feed stream, particularly a feed gas, into one end of a heated catalyst bed containing or consisting of the catalytically active or activatable mixture described above, and removing a product stream from the other end of the catalyst bed.

[0139] The description and preferred embodiments of catalytically active or activatable mixtures for use in chemical reactors, their composition and properties (including the properties of the components) correspond to the above description of these characteristics of catalytically active or activatable mixtures.

[0140] Examples of chemical reactions that require a continuous energy input in the form of heat and can be carried out in the presence of the catalytically active or activatable mixtures of the present invention are endothermic or highly endothermic reactions as mentioned above.

[0141] Highly endothermic reactions include pyrolysis, dehydrogenation, and reforming reactions.

[0142] Highly endothermic reactions can also be described by their volumetric energy consumption in the heating zone, which is preferably greater than 0.5 MW / m³. 3 More preferably, greater than 1 MW / m 3 Especially those greater than 2 MW / m 3 For example, energy consumption in the heating zone can range from 0.5 to 10 MW / m². 3 between.

[0143] The preferred chemical reaction according to the method of the present invention is an endothermic gas-phase reaction selected from the group consisting of the following reactions: steam methane reforming (SMR), dry reforming of methane, dehydrogenation of alkanes such as propane dehydrogenation, production of HCN (BMA) from methane and ammonia, production of (dry) formaldehyde from methanol, production of acetaldehyde from ethanol, production of syngas from methanol, dehydrogenation of cyclohexanol, production of butadiene from acetaldehyde and ethanol, dehydration of alcohols to olefins, dehydration of acetic acid to ketene, production of HCN (BMA) from formamide, production of acrolein from glycerol, and reverse water-gas shift (RWGS).

[0144] In one embodiment of the invention, the method of the invention for carrying out a chemical reaction catalyzed by a shaped catalyst body of a catalytically active or activatable mixture as described in the above description is characterized in that the chemical reaction is selected from the group consisting of: steam methane reforming (SMR), dry reforming of methane, alkane dehydrogenation such as propane dehydrogenation, production of HCN (BMA) from methane and ammonia, production of (dry) formaldehyde from methanol, production of acetaldehyde from ethanol, production of syngas from methanol, dehydrogenation of cyclohexanol, production of butadiene from acetaldehyde and ethanol, production of olefins from alcohol dehydration, production of ketene from acetic acid dehydration, production of HCN (BMA) from formamide, production of acrolein from glycerol, and reverse water-gas shift (RWGS).

[0145] The present invention further provides a chemical reactor for carrying out chemical reactions, preferably endothermic or highly endothermic reactions, the chemical reactor containing a catalyst bed comprising or consisting of a catalytically active or activatable mixture as described in the above description.

[0146] The description and preferred embodiments of catalytically active or activatable mixtures for use in chemical reactors, their composition and properties (including the properties of the components) correspond to the above description of these characteristics of catalytically active or activatable mixtures.

[0147] A chemical reactor comprising the catalytically active or activatable mixture of the present invention disclosed above as part of or as a directly electrically heated catalyst bed is a moving bed reactor or a fixed bed reactor, preferably a fixed bed reactor.

[0148] In one embodiment of the present invention, the chemical reactor of the present invention is characterized in that the chemical reactor is a fixed-bed reactor.

[0149] Suitable chemical reactors comprising directly electrically heated catalyst beds have been previously described. Examples of such reactors are described, for example, in WO 2019 / 145279 (title: Device packed with solid material for performing endothermic reactions with direct electrical heating), WO 2020 / 200522 (title: Reactor for endothermic high-temperature reactions), WO 2022 / 194775 (title: Reactor and method for the pyrolysis of hydrocarbon-containing fluids), or in the introduction to this specification. The electrically heated solid bed inside the chemical reactor is typically in contact with at least one pair of electrodes to conduct current through the reactor bed.

[0150] In another embodiment of the invention, the chemical reactor of the invention is characterized in that the chemical reactor can be electrically heated via at least one pair of electrodes that conduct current through a reactor bed composed of the catalytically active or activatable mixture.

[0151] The present invention is illustrated by the following examples, but these examples do not limit the scope of the invention.

[0152] Each figure is based on a percentage by weight, unless otherwise expressly stated. Example

[0153] Measurement of resistivity in a fixed bed:

[0154] An experimental setup for studying the resistivity of a fixed bed containing a physical mixture of conductors and non-conductors. Figure 1 As shown in the diagram, four sensing electrodes E1-E4 enable spatial resolution of resistivity measurements, thus providing a measurement of the quality of the bed filling in terms of uniformity. A specific compressive force can be applied to the top of the filled bed. To avoid significant temperature rise during measurement, the DC power is limited to 1 W during measurement.

[0155] To determine the diameter ratio (d) of the catalyst (non-conductive) to the conductor... cat / d con The effects of ) and volume mixing ratio (V cat / (V cat +V con To conduct a basic study on the effects of γ-Al₂O₃, electrode graphite was selected as an example of a conductor, while white quartz gravel was chosen as a model of a catalyst body (non-conductor). In other experiments focusing on the shape and density of non-conductors, extrusions of γ-Al₂O₃ were used as models of mixtures of non-conducting catalyst bodies.

[0156] Example 1

[0157] The ratio between the characteristic diameter of the shaped catalyst body (non-conductive) and the diameter of the conductive body (d) cat / d con The effects of ) and volume mixing ratio (V cat / (V cat +V con The effects of the conductive and non-conductive materials were measured separately. The conductive and non-conductive materials were premixed in beakers and then transferred to the apparatus. A compressive force of 200 N was applied during each measurement. Selected mixtures were photographed in... Figure 2 The results are shown in [the table / document] and presented in [the table / document]. Figure 3 The resistivity of the fixed bed containing graphite is in the range of 0.5 mΩm. The resistivity increases with increasing volume fraction of non-conductive material. Keeping the volume fraction of non-conductive material constant, the resistivity increases with the ratio (d...). cat / d con The resistivity increases as the electrode graphite and quartz gravel decrease. The fixed-bed resistivity ranges from 1 to 30 mΩm, which can be obtained by mixing electrode graphite and quartz gravel.

[0158] The uniformity of a fixed bed is another important parameter for catalytic applications. Local variations in the composition of a fixed bed result in different resistivities, which in turn lead to uneven energy input and temperature variations. Figure 4 Statistical assessments of fixed-bed resistivity measured at different locations in the apparatus (electrodes E1-E2, E2-E3, E3-4) and in repeated experiments are presented. The limiting factors for adequate distribution within the packing material depend on the diameter ratio of the non-conductive (catalyst) to the conductive material and the respective volume fractions of the non-conductive (catalyst) and conductive materials. Adding only 33 vol% of catalyst to the mixture can achieve adequate distribution within the packing material. cat / d con Sufficient distribution was achieved across the entire range (0.4–2.6). Conversely, the addition of 50 vol% and 67 vol% catalyst bulk to the mixture required at least dm of 1.0 and 1.7, respectively, for sufficient distribution. cat / d con Some results from Example 1 are summarized in Table 1.

[0159] Table 1 shows the results of resistivity measurements in Experiment 1 (a mixture of electrode graphite and quartz gravel) and Experiment 2 (a mixture of electrode graphite and γ-Al2O3 extrusion).

[0160] Table 1

[0161]

[0162] a) Electrode voltage between electrode E1 and electrode E4.

[0163] b) For the experiment in Example 1 (where the molded catalyst body was replaced with quartz gravel), d cat Determined by sieving particle size.

[0164] c) Here, gasoline tar is used as a conductive material, which has a lower bulk conductivity than the electrode graphite used in other experiments.

[0165] Example 2

[0166] To investigate the effects of bulk shape and packing density, the conductors comprised electrode graphite (size particle size 2.0–3.15 mm), while the non-conductors comprised 1 / 8'' γ-Al₂O₃ extrusions with a mass-based average length of 8.1 mm. According to https: / / en.wikipedia.org / wiki / Sphericity, the average sphericity Ψ of these bulks was 0.8. Because graphite and porous γ-Al₂O₃ provided significantly different packing densities, a homogeneous physical mixture of bulks could not be produced by manually premixing the fractions in a beaker. Instead, a uniformly distributed catalyst bed in the apparatus was generated using a mixing sluice. The resulting fixed-bed resistivity was close to that for d cat / d con The resistivity of the graphite / quartz gravel mixture with a value of 2.6 is shown in Table 1. This finding indicates that the decisive size of the studied γ-Al₂O₃ extrudate is based on the product of the mass-average length and the average sphericity, thus yielding d0. cat / d con = 2.5.

[0167] Example 3

[0168] The combination of fixed-bed resistance heating and endothermic catalysis was achieved in a 1 ml-scale double-walled vacuum-insulated laboratory reactor. The reactor was designed to minimize heat loss in the radial direction. The catalyst bed was fixed axially between two electrodes. Results from direct-heated catalysis experiments were compared with reference experiments in a conventional laboratory reactor using external heating through the reactor walls. The endothermic gas-phase dehydration of ethanol to ethylene on γ-Al₂O₃ as a heterogeneous catalyst was used as a probe reaction. For resistance heating, the catalyst was combined with graphite electrodes of the same size (d... cat / d con = 1.0) Mixture. The reaction temperature varied between 250°C and 350°C. Details of the test conditions are listed in Table 2 along with the results of the catalytic studies.

[0169] Table 2 shows the results of catalytic tests using resistance heating and conventional reactor heating. The test conditions were as follows: WHSV = 3.2 h. -1 (Based on EtOH and Al2O3), the feed composition is 90% EtOH in Ar, at atmospheric pressure, d cat = 300-500µm, DEE = diethyl ether.

[0170] Table 2

[0171]

[0172] The catalytic performance of direct resistance heating of the catalyst bed in terms of EtOH conversion and C2H4 selectivity is very similar to that of conventional external heating with a heating cylinder. This indicates that the temperature distribution is similar (uniform) in both reactor configurations and underscores that the energy efficiency associated with direct resistance heating does not (negatively) affect the catalytic performance in fixed-bed reactors.

[0173] Example 4

[0174] In addition to Experiment 3, resistance-heated ethanol dehydration was also performed in a larger 500 ml laboratory reactor. This reactor was equipped with several independent external heating zones to compensate for radial heat loss, or alternatively used as external heating in the reference experiment without direct resistance heating. Similar to the 1 ml scale apparatus, the catalyst bed was fixed axially between the two electrodes. The results of the directly heated catalytic experiments were compared with those of the reference experiments using (i) external heating only in the catalytic reaction zone, or (ii) external heating in the reactor preheater and prebed. Similarly, the γ-Al₂O₃ catalyst was compared with the same-sized graphite electrode (d cat / d con = 1.0) Mixture. Details of the test conditions are listed in Table 3 along with the results of the catalytic studies.

[0175] Table 3 shows the results of catalytic tests using resistance heating and conventional reactor heating. The test conditions were as follows: WHSV = 0.3 h. -1 (Based on EtOH and Al2O3), the feed composition is EtOH / H2O = 1:2 (by weight), diluted with 10 mol% Ar, at atmospheric pressure, d cat = 1-2 mm, DEE = diethyl ether.

[0176] Table 3

[0177]

[0178] The results show that direct resistance heating of the catalyst fixed bed is energy efficient. A heating power of 60 W resulted in a peak reactor temperature of 385°C and complete EtOH conversion. Reference experiments using an external heating device with the same heating power were significantly affected by heat transfer limitations through the catalyst bed, and regardless of the location of the external heating, EtOH conversion exceeding 50% could not be achieved.

[0179] Example 5: Determination of the diameter, characteristic diameter, and average diameter of multiple bodies

[0180] The characteristic diameter d of the shaped catalyst body or shaped conductor (which is a ratio d) cat / dcon The relevant dimensions are defined as the diameter d of the circumscribed sphere surrounding the molded body. css The sphericity Ψ of the convex hull of the molded body ch The product of the lengths. In the case of extrudates with a certain distribution along their length, the average length based on mass should be used in the calculation.

[0181]

[0182] Among them Ψ ch The volume V of the convex hull of the molded body ch Surface area A of the convex hull of the molded body ch function

[0183]

[0184] The characteristic diameter of a catalyst body or conductor (for which the hull is a cylinder with diameter D and length L) is described as follows:

[0185]

[0186] for Figure 5 The bodies shown in Table 4 are some characteristic lengths of the typical shapes of the selected catalyst bodies.

[0187] Table 4

[0188]

[0189] Figure 1 Experimental apparatus used to study the resistivity of a fixed bed.

[0190] 1. Main Components

[0191]

[0192] 2. Packed bed and test tube dimensions

[0193]

[0194] Figure 2 Top row: Fixed bed (d) with different volume fractions of non-conductive (catalyst) substances cat / d con = 1.0);

[0195] Bottom row: with different diameter ratios d ranging from 0.4 (left) to 2.6 (right). cat / d con (V) cat Fixed bed (50 vol%).

[0196] Figure 3The resistivity of a fixed bed containing both non-conductive (catalyst) and conductive materials. Ratio d cat / d con The values ​​ranged from 0.4 to 2.6, with the highest volume fraction of the non-conductive (catalyst) studied reaching 67 vol%. The x-axis shows the "catalyst replacement volume fraction (vol%)", and the y-axis shows the "fixed bed resistivity ρ (mΩm) at 20°C".

[0197]

[0198] Figure 4 : The coefficient of variation of resistivity of a fixed bed containing both non-conductive (catalyst) and conductive materials. The x-axis shows d cat / d con The y-axis shows the "catalyst replacement volume fraction (vol%)". The scale from 0 to 70 represents the "coefficient of variation (%)".

[0199]

[0200] Figure 5 The first line shows a top view of the different bodies. The second line shows a side view of the bodies. Figure 5 'a' indicates a piece; Figure 5 b represents a ring; Figure 5 c represents a sphere; Figure 5 d indicates a four-leaf lobes (4 holes); Figure 5 'e' represents the star-shaped extrusion. The dashed line shows the projection of the corresponding body's circumscribed sphere.

Claims

1. A catalytically active or activatable mixture for use in a chemical reactor, comprising... i) A molded catalyst body containing catalytically active or activatable materials, and ii) Conductors, The characteristic diameter d of these shaped catalyst bodies cat With the diameter d of these conductors con The ratio between (d) cat / d con ) in the range of 1.5 to 3, and These shaped catalyst bodies have a characteristic diameter d in the range of 1 mm to 50 mm. cat ,and The diameter of the unformed conductor is the average diameter determined by sieving according to DIN 66165, and The characteristic diameters of the shaped catalyst body and the shaped conductor are defined as the diameter d of the outer sphere surrounding the shaped body. css The sphericity Ψ of the convex hull of the molded body ch The product of.

2. The catalytically active or activatable mixture according to claim 1, wherein, The chemical reactor is either a moving bed reactor or a fixed bed reactor.

3. The catalytically active or activatable mixture according to claim 1 or 2, wherein, These molded catalyst bodies containing catalytically active or activatable materials have a uniform geometric configuration, wherein the molded bodies with a uniform geometric configuration are very similar or identical in shape and at least two dimensions.

4. The catalytically active or activatable mixture according to any one of claims 1 to 3, wherein, These conductors have uniform or non-uniform geometries.

5. The catalytically active or activatable mixture according to any one of claims 1 to 4, wherein, These molded catalyst bodies have different chemical compositions than these conductors.

6. The catalytically active or activatable mixture according to any one of claims 1 to 5, wherein, The catalytically active or activatable mixture exhibits activity at 20°C for 10... -4 - 10 2 Fixed bed resistivity in the Ωm range.

7. The catalytically active or activatable mixture according to any one of claims 1 to 6, wherein, These conductors have a conductivity of 10 at 20°C. -8 - 10 -2 Volume resistivity in the Ωm range.

8. The catalytically active or activatable mixture according to any one of claims 1 to 7, wherein, These conductors contain or are composed of conductive materials. The conductive material is selected from the group consisting of: metals, metal alloys, non-metallic resistive materials, metal carbides, transition metal nitrides, metal borides, metal silicides, metal phosphides, and materials containing at least 60% sp. 2 - Carbon in polymorphs of hybrid carbon atoms, superionic conductors, phosphate electrolytes, mixed oxides doped with lower valence cations, mixed sulfides doped with lower valence cations, composite materials containing at least 30% by weight of any of the aforementioned conductive materials, and any mixtures thereof.

9. The catalytically active or activatable mixture according to any one of claims 1 to 8, wherein, The volume fraction of these molded catalyst bodies containing catalytically active or activatable materials is in the range of 0.4 to 0.95, and the volume fraction of these conductors is in the range of 0.05 to 0.

60.

10. The catalytically active or activatable mixture according to any one of claims 1 to 9, wherein, These molded catalyst bodies have aspect ratios in the range of 1 to 10, and these conductors have aspect ratios in the range of 1 to 10.

11. A method for preparing a catalytically active or activatable mixture according to any one of claims 1 to 10, This method includes at least the following method steps. (a) Mixing the shaped catalyst bodies of a defined volume with the conductors of a defined volume.

12. Use of the catalytically active or activatable mixture according to any one of claims 1 to 10 in a chemical reactor as part of or as a directly electrically heated catalyst bed.

13. A method for carrying out a chemical reaction catalyzed by these molded catalyst bodies of catalytically active or activatable mixtures according to any one of claims 1 to 10. The method includes the following steps (b) Establishing a catalyst bed in a chemical reactor comprising a catalytically active or activatable mixture or composed thereof according to any one of claims 1 to 10, the chemical reactor comprising at least one pair of electrodes through which an electric current can be conducted through the catalyst bed comprising the catalytically active or activatable mixture or composed thereof. (c) Heating the catalyst bed comprising or consisting of the catalytically active or activatable mixture by applying a voltage to each pair of electrodes, and (d) Introducing a feed stream, particularly a feed gas, into one end of a heated catalyst bed comprising or consisting of the catalytically active or activatable mixture according to any one of claims 1 to 10, and removing a product stream from the other end of the catalyst bed.

14. A chemical reactor for carrying out a chemical reaction, the chemical reactor containing a catalyst bed comprising or consisting of a catalytically active or activatable mixture according to any one of claims 1 to 10.

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