Structured ceramic catalyst and corresponding reactor

Abstract

The present invention relates to an electrically heated structured ceramic catalyst (30) for catalysing an endothermic reaction of a reactive mixture stream to be converted into a product gas, the catalyst (30) comprising at least one macroscopic ceramic structure (32) supporting a catalytically active material, enabling the conversion of the reactive mixture stream into the product gas and containing at least two electric heating means (40a, 40b, 40c, 40d, 40e, 40f), with at least some of, in particular each of, the electric heating means (40a, 40b, 40c, 40d, 40e, 40f) extending in a meandered or meandering way within at least one plane (42a, 42b, 42c, 42d, 42e, 42f) allocated or assigned to the respective electric heating means (40a, 40b, 40c, 40d, 40e, 40f), in particular with the planes (42a, 42b, 42c, 42d, 42e, 42f) being parallel to each other.

Description

[0001] S T R U C TU R E D C E RAM I C CATA LYS T A N D C O R R ES P O N D I G R EAC T O R

[0002] Technical field

[0003] The present invention refers to a structured catalyst catalyzing an endothermic reaction of a reactive mixture stream where heat for the endothermic reaction is provided by direct electric heating, as well as to a reactor system for carrying out such reactions.

[0004] Technological background and prior art

[0005] Electrically heated reactors for energy intensive chemical reactions to convert a reactive mixture stream into a product steam can significantly reduce carbon dioxide (CO2) emissions by replacing fossil fuels with electricity for process heat generation.

[0006] Generating the necessary heat directly inside the reactor by resistive (joule) heating, avoids the necessity to generate heat outside and transfer it into the pressure vessel.

[0007] This enables a cold skin pressure vessel design with internal refractory lining, that both increases efficiency and allows to operate at higher temperatures compared to traditional fired reactors.

[0008] Disclosure of the present invention: object, solution, advantages

[0009] In a first aspect, an electrically heated structured ceramic catalyst for catalysing an endothermic reaction of a reactive mixture stream to be converted into a product gas is provided. Said structured ceramic catalyst is extending in a longitudinal direction from a first end to a second end, where said first end forms an inlet to said macroscopic ceramic structure for said reactive mixture stream and said second end forms an outlet for said product gas.

[0010] Said structured ceramic catalyst comprises at least one macroscopic ceramic structure which supports a catalytically active material.

[0011] Said catalytically active material enables the conversion of said reactive mixture stream into product gas.

[0012] The electrically heated structured ceramic catalyst contains at least two electric heating means, with at least some of, in particular each of, the electric heating means extending in a meandered or meandering way within at least one plane allocated or assigned to the respective electric heating means, in particular with the planes being parallel to each other; in particular, the electrically heated structured ceramic catalyst contains at least two heating means which are extending in a meandered or meandering way within at least two, in particular parallel, planes, in particular forming at least two electric heating elements installed in parallel. It is an objective of the present invention to provide a solution against the background of possible failure of individual heating means.

[0013] It is a further objective of the present invention to provide a solution that increases both performance of the electrically heated structured ceramic catalyst, minimizes slip of unreacted inlet gases and increases lifetime of the system.

[0014] It is a further objective of the present invention to provide a solution that is mechanically more robust.

[0015] It is a further objective of the present invention to provide a solution that is easier and faster to manufacture.

[0016] In a further aspect, a reactor system for carrying out an endothermic reaction of a reactive mixture stream is provided.

[0017] Said reactor system comprises:

[0018] - a structured ceramic catalyst that contains at least two heating means extending in a meandered or meandering way within two parallel planes forming two in parallel installed electric heating means;

[0019] - a pressure shell housing, hosting the ceramic structured catalyst;

[0020] - a refractory layer between said structured ceramic catalyst and said pressure shell (housing).

[0021] Electrically heated reactors can generate the heat necessary for an endothermic chemical reaction directly inside the reactor within the structured ceramic catalyst, thus avoiding the necessity to transfer heat from outside into the pressure vessel. This allows a cold skin pressure vessel design with internal refractory lining, that both increases efficiency and allows to operate at higher temperatures compared to traditional fired reactors.

[0022] As used herein, the term "electrically heated structured ceramic catalyst" is meant to denote a combination of a macroscopic ceramic structure (or ceramic macrostructure), a catalytically active material supported on the external surface of said macrostructure, and heating means, said heating means embedded within the macroscopic ceramic structure, and said heating means for generating the heat for said endothermic reactions, in particular necessary for said endothermic reactions.

[0023] According an expedient embodiment of the present invention, the macroscopic ceramic structure may comprise at least one hollow flow path, in particular in such way that the hollow flow path(s) may extend through said macroscopic ceramic structure.

[0024] In a preferred embodiment of the present invention, said heating means may be arranged or located or provided within said hollow flow path(s) of said macroscopic ceramic structure, It should be noted that it is not a necessity that all heating means are (completely) incorporated into the hollow flow paths of the macroscopic ceramic structure. In a preferred configuration however, more than about 85 percent of the length of the heating means is located within the hollow flow paths of the macroscopic ceramic structure.

[0025] The term "hollow flow path" is meant to denote a space within the macroscopic ceramic structure, that enables a flow of gas to pass through the macroscopic ceramic structure. The diameter of the hollow flow path is larger than the diameter of the heating mean placed inside, but small enough to ensure a close proximity between ceramic and heating mean. The geometry of the hollow flow path can be round, squared, star shaped, trigonal, or have any other shape.

[0026] It should be understood that the catalytically active material does not necessarily have an equal distribution across the entire surface of the macroscopic ceramic structure, but can also be predominantly localized in a certain part of said macrostructure or have a concentration gradient. It is for example possible, that the amount of catalytically active material supported on the surface of the macroscopic ceramic structure is gradually increasing from inlet to outlet.

[0027] In a preferred configuration, the catalytically active material is homogeneously distributed across the external surface of the macroscopic ceramic structure within the hollow flow path.

[0028] An embodiment of an electric reactor, in particular of a compact electric reactor, may comprise a structured ceramic catalyst for catalyzing an endothermic reaction of a feed gas to convert it to a product gas. Said structured ceramic catalyst may comprise at least one macroscopic ceramic structure which supports a catalytically active material. Said catalytically active material enables said conversion of said reactive mixture stream into said product gas.

[0029] The electrically heated structured ceramic catalyst may contain at least two resistive heating means which may extend in a meandered way within two parallel planes forming two in parallel installed heating zones.

[0030] The heating means may be located within the hollow flow paths. In this way, an annular gap is formed between heating mean and the wall of the hollow flow path within the macroscopic ceramic structure. The catalytically active material is supported on the surface of the macroscopic ceramic structure within the hollow flow path. The inlet feed is passing through the annular gap its way from the inlet to the outlet of the structured ceramic catalyst.

[0031] Due to the arrangement of individual resistive heating means meandered in parallel planes of the structured ceramic catalyst, different planes of the structured ceramic catalyst may, in particular directly, be heated by different heating means.

[0032] In the event of one heating means failing, the respective plane will not be heated anymore by the failed heating means located in this plane. As each plane has at least one direct neighbour in the form of a parallel plane heated by a different heating means, heat can be transferred from said working heating means plane to said failed heating means plane.

[0033] Except of heating means located at the very top plane of the structured ceramic catalyst or at the very bottom plane of the structured ceramic catalyst, a plane with a failing heating means gets heat transferred from both the adjacent or neighboured planes. In most cases this mechanism can almost completely compensate the failed heating means and minimize loss in performance of the reactor system.

[0034] For the purpose of manufacturing such a system of an electrically heated structured ceramic catalyst that contains heating means extending in a meandered or meandering way within multiple parallel planes, heating wires need to be introduced in the hollow flow path of the structured ceramic catalyst. As the heating wires have a certain mechanical stability, a certain shape of ceramic support is required to effectively achieve this configuration.

[0035] In a preferred configuration, the structured ceramic catalyst is built up out of individual hollow flow paths, which as an assembly form the macroscopic ceramic structure.

[0036] For assembling an electrically heated structured ceramic catalyst having resistive heating means disposed in parallel planes, it is possible to use individual single hole ceramic subunits which enable to meander relatively rigid resistive heating means minimizing the number of single resistive heating means.

[0037] With the heating means not necessarily arranged or located or provided within the hollow flow path(s) of the macroscopic ceramic structure, the heating means may advantageously be arranged or located or provided in one or more plane(s) between the ceramic subunits.

[0038] In a preferred configuration of the present invention, said ceramic subunit has a plate-like shape, in particular embodied as an essentially two-dimensional arrangement. Independently thereof or in combination therewith, said at least two hollow flow paths may succeed in only one direction.

[0039] In comparison to individual single hole ceramic subunits that lead to an assembly of large quantities of individual single ceramic subunits bundled together within a structured ceramic catalyst, the usage of multichannel subunits can dramatically reduce the number of individual subunits. This leads to a mechanically more stable assembly which is also easier to insert, stabilize and remove from a pressure vessel.

[0040] Additionally, the number of interfaces between individual subunits is significantly reduced. This leads to a minimized risk of reactive mixture streams channeling through the interface between single subunits. Such channeling needs to be avoided, as in this way the gas is not in direct contact with the heating mean, thus reducing the efficiency of heat transfer.

[0041] Additionally, a lower number of individual subunits also leads to a more a uniform radial temperature profile, as slight deviations in heat generation and consumption between individual flow path can be balanced.

[0042] Preferentially, a single resistive heating mean is meandered through hollow flow path of ten to 200 ceramic subunits within one plane, more preferentially between twenty to eighty ceramic subunits.

[0043] Optionally, several heating means may be connected together directly welding them or by using an electrical connector. These electrical connectors or welding are preferably located on the side of the structured ceramic catalyst where the reactive gas stream enters the structured ceramic catalyst benefitting of the lower temperatures.

[0044] The described reactor system is engineered to efficiently heat both the catalytically active material and the gases passing through it by ensuring close proximity between the individual or single heating means, catalytically active material and the gas. The goal is to achieve high temperatures within the structured ceramic catalyst, preferably around 1000°C, or even higher, such as 1150°C, to facilitate the desired chemical reactions under given operating conditions.

[0045] The composition of the catalytically active material can be customized based on specific reaction requirements and operating conditions. Among the materials used for the heating means or heating elements, Iron (Fe), Chromium (Cr), Aluminum (Al), or their alloys are preferred due to their suitability for efficient heating and compatibility with the high temperatures required for the process.

[0046] It is an objective of the present invention to provide a structured ceramic catalyst that consists of a minimized number of individual ceramic subunits while maintaining a meandered configuration, in which individual resistive heating means provide heat in parallel planes of the structured ceramic catalyst.

[0047] To achieve this, single hole ceramic subunits are replaced by multi-hole ceramic subunits, which were designed in a way, that it is still possible to assemble an electrically heated structured ceramic catalyst with meandered heating means having resistive heating means installed in parallel planes.

[0048] For this purpose, a two-dimensional hollow path arrangement within a single ceramic subunit is disclosed which is herein denoted as "plate". Each plate hosts at least two hollow flow path which extend throughout the entire plate.

[0049] Feed gas can flow from an inlet section through the hollow flow path of the plate to an outlet section of the plate. In a preferential configuration, between four and twenty hollow flow paths are presents in one individual plate. After assembly the electrically heated structured ceramic catalyst, at least two hollow flow paths within one individual plate host a heating mean.

[0050] At least two, preferably between ten and 200, individual plates are hosting the same heating mean inside their hollow flow path within one plane. A single heating mean is connecting separate plates in a meandered configuration.

[0051] As each plate can host a multiplicity of meandered heating means within parallel planes, the mechanical stability is greatly improved compared to an assembly involving ceramic subunits with single hollow flow path. This is beneficial for handling the assembly during manufacturing, distribution, installation and removal of the assembly, but also for the overall lifetime of the assembly during operation.

[0052] At the same time, the higher mechanical stability reduces the likelihood of damaging the assembly as well as facilitating handling. While a typical assembly involves from ten to 200 plates, an equivalent assembly using subunits with only one hollow flow path each, will require at least 2000 individual ceramic subunits.

[0053] The decreased number of individual subunits not only boosts the mechanical properties of the assembly, but also drastically reduces production time. Production of a hundred plates assembly comprising plates with ten hollow flow paths each, requires approximately double the time compared to an assembly having hundred single hollow flow path subunits. It results that the total assembly time is reduced by a factor of five when using the plate design.

[0054] Reducing the number of individual subunits also reduces interfaces thus discontinuity. This results in the following benefits:

[0055] - Reduced number of gaps between the subunits, which leads to an increased conversion of reactive mixture as a lower amount of reactive mixture stream flows though the gap, avoiding optimal contact to the heating means.

[0056] - Minimized temperature gradients within the electrically heated structured ceramic catalyst that may arise from channeling of the reactive gas mixture between the gaps formed at the interfaces of the adjacent or neighboured ceramic subunits and from the missing material continuity which helps to homogenize the temperature via conduction.

[0057] - Reduced amount of needed catalytically active phase used in the preparation of the structured ceramic catalyst. Deposition of the catalytically active phase on the ceramic subunits is primarily needed inside the hollow flow paths. However, it is often practically easier to produce ceramic subunits where the catalytically active phase is on all surfaces. Reducing the external geometric surface area of the assembly will reduce the amount of catalytically active phase used during production process. A reactor system for carrying out an endothermic reaction of a feed gas is provided, said reactor system comprising:

[0058] - an electrically heated structured ceramic catalyst;

[0059] - a pressure shell housing, hosting the structured ceramic catalyst;

[0060] - a refractory lining between said structured ceramic catalyst and said pressure shell housing.

[0061] It is important to note that any feature mentioned in conjunction with the structured ceramic catalyst can also be integrated into the reactor system for conducting an endothermic reaction of a fed gas, and vice versa. This means that the elements and design considerations discussed are applicable and interchangeable between both the structured ceramic catalyst and the reactor system.

[0062] The reactor system is designed to feed a reactive gas stream through an inlet, directing it into the pressure shell. Within this shell, a configuration comprising heat insulation materials and inert materials is positioned to guide the feed gas through the formed annular gaps of the structured ceramic catalyst.

[0063] Here, the gas comes into direct contact with both the heating means and the catalytically active material supported on the macroscopic ceramic structure. This catalytically active material plays a crucial role in converting the reactive mixture stream into a product stream. Moreover, the heating of the structured ceramic catalyst provides the necessary heat for the endothermic reaction to occur effectively.

[0064] Finally, the resulting product gas from the structured ceramic catalyst is channeled towards the reactor outlet for further processing. Within the structured ceramic catalyst, the temperature profile may demonstrate a progressively increasing temperature as the feed gas flows through from the inlet to the outlet.

[0065] Due to the heat generation inside the structured ceramic catalyst via the therein hosted resistive heating means, no heat needs to be transferred through the pressure shell. This allows for a reactor design involving a cold skin pressure vessel. The uniform distribution of heating means throughout the structured ceramic catalyst facilitates a very uniform radial temperature profile. Both these aspects lead to a reactor that has much more energy efficiency and at the same time reach higher operating temperatures compared to a fired equipment.

[0066] It is important to note that a skilled individual would readily acknowledge that any feature described in conjunction with the electrically heated structured ceramic catalyst and the reactor system for facilitating an endothermic reaction of a feed gas is also applicable for this purpose. Therefore, the comments provided regarding the structured ceramic catalyst and the reactor system are equally relevant to their use in this context. Brief explanation of the drawings

[0067] As already discussed above, there are various possibilities for embodying and further developing the teaching of the present invention in an advantageous manner. For this purpose, on the one hand reference is made to the claims dependent on claim 1 and on claim 14, and on the other hand further embodiments, features and advantages of the present invention are explained in greater detail below, inter alia by way of the exemplary embodiments illustrated by Fig. 1 to Fig. 3, wherein:

[0068] Fig. 1 shows, in compliance with the present invention, a perspective view of an embodiment of a structured ceramic catalyst with ceramic macrostructure;

[0069] Fig. 2A shows, in compliance with the present invention, a perspective view of an exemplary embodiment for a ceramic subunit of the structured ceramic catalyst, six of said ceramic subunits being vertically arranged in Fig. 1 ;

[0070] Fig. 2B shows, in compliance with the present invention, a perspective view of an alternative exemplary embodiment for a ceramic subunit of the structured ceramic catalyst, six of said ceramic subunits being vertically arranged in Fig. 1 ;

[0071] Fig. 2C shows, in compliance with the present invention, a perspective view of a still alternative exemplary embodiment for a ceramic subunit of the structured ceramic catalyst, six of said ceramic subunits being vertically arranged in Fig. 1 ; and

[0072] Fig. 3 shows, in compliance with the present invention, a cross section of an exemplary embodiment for a reactor system, comprising the structured ceramic catalyst from Fig. 1 , a pressure shell and a refractory layer in between.

[0073] Like or similar embodiments, elements or features are provided with identical reference signs in Fig. 1 to Fig. 3.

[0074] Best way for embodying the present invention; detailed disclosure of exemplary embodiments of the present invention

[0075] Fig. 1 shows an electrically heated structured ceramic catalyst 30 for catalysing an endothermic reaction of a reactive mixture stream to be converted into a product gas.

[0076] The catalyst 30 comprises a ceramic macrostructure (= macroscopic ceramic structure 32, with its material selected from the group consisting of SiOz, AI2O3, Y2O3, WO3, ZrOz, TiOz, MgO, CaO, FeOz, ZnOz and combinations thereof) supporting catalytically active material, the catalytically active material selected from the group of d-block elements or combinations thereof, optionally including the addition of alkali, earth alkali and / or lanthanide elements (at least one of the alkali, the earth alkali and / or the lanthanide elements may be added to the catalytically active material), and thus enabling the conversion of the reactive mixture stream into the product gas.

[0077] The catalyst 30 contains six electric heating means 40a, 40b, 40c, 40d, 40e, 40f extending in a meandered or meandering way (-->

[0078] - reference sign 41a, designating in Fig. 1 a meandered part or section of the first or highest electric heating means 40a;

[0079] - reference sign 41 b, designating in Fig. 1 a meandered part or section of the second heating means 40b;

[0080] - reference sign 41c, designating in Fig. 1 a meandered part or section of the third heating means 40c;

[0081] - reference sign 41d, designating in Fig. 1 a meandered part or section of the fourth heating means 40d;

[0082] - reference sign 41 e, designating in Fig. 1 a meandered part or section of the fifth heating means 40e;

[0083] - reference sign 41 f, designating in Fig. 1 a meandered part or section of the sixth or lowest electric heating means 40f

[0084] ) within six allocated or assigned planes 42a, 42b, 42c, 42d, 42e, 42f parallel to each other (->

[0085] - reference sign 42a, designating in Fig. 1 the first or highest plane, allocated or assigned to the first or highest meandered electric heating means 40a;

[0086] - reference sign 42b, designating in Fig. 1 the second plane, allocated or assigned to the second meandered electric heating means 40b;

[0087] - reference sign 42c, designating in Fig. 1 the third plane, allocated or assigned to the third meandered electric heating means 40c;

[0088] - reference sign 42d, designating in Fig. 1 the fourth plane, allocated or assigned to the fourth meandered electric heating means 40d;

[0089] - reference sign 42e, designating in Fig. 1 the fifth plane, allocated or assigned to the fifth meandered electric heating means 40e;

[0090] - reference sign 42f, designating in Fig. 1 the sixth or lowest plane, allocated or assigned to the sixth or lowest meandered electric heating means 40f

[0091] ) and containing or taking up the six electric heating means 40a, 40b, 40c, 40d, 40e, 40f installed in parallel.

[0092] The ceramic macrostructure 32 comprises, and in Fig. 1 consists of, six ceramic subunits 31 , with the ceramic macrostructure 32 formed from a multiplicity of (in Fig. 1 : six) juxtaposed ceramic subunits 31 , each ceramic subunit 31 geometrically being plate-like or in a plate shape design, in particular embodied as an essentially two-dimensional arrangement, with the hollow flow paths 313 succeeding essentially in only one direction, cf.

[0093] - first embodiment: seven hollow flow paths 313 succeeding to each other in a line, in Fig. 2A in a horizontal line;

[0094] - second embodiment: seven hollow flow paths 313 succeeding to each other in a zig-zag pattern, in

[0095] Fig. 2B in a horizontal zig-zag pattern;

[0096] - third embodiment: four hollow flow paths 313 succeeding to each other in a line, in Fig. 2C in a diagonal line.

[0097] In this context or independently thereof, the ceramic subunits 31 may be in the shape of a honeycomb, of a monolith, of a pellet, of a tube or of foam.

[0098] With the six individual or single electric heating means 40a, 40b, 40c, 40d, 40e, 40f incorporated within a respective hollow flow path 313 of the ceramic macrostructure 32, each electric heating means 40a, 40b, 40c, 40d, 40e, 40f is meandered (->

[0099] - reference sign 41a, designating in Fig. 1 a meandered part or section of the first or highest electric heating means 40a defined in the first or highest plane 42a;

[0100] - reference sign 41 b, designating in Fig. 1 a meandered part or section of the second heating means 40b defined in the second plane 42b;

[0101] - reference sign 41c, designating in Fig. 1 a meandered part or section of the third heating means 40c defined in the third plane 42c;

[0102] - reference sign 41d, designating in Fig. 1 a meandered part or section of the fourth heating means 40d defined in the fourth plane 42d;

[0103] - reference sign 41 e, designating in Fig. 1 a meandered part or section of the fifth heating means 40e defined in the fifth plane 42e;

[0104] - reference sign 41 f, designating in Fig. 1 a meandered part or section of the sixth or lowest electric heating means 40f defined in the sixth or lowest plane 42f

[0105] ) within each respective plane 42a, 42b, 42c, 42d, 42e, 42f and passes through the respective hollow flow path 313.

[0106] As can be taken from Fig. 1 , the planes 42a, 42b, 42c, 42d, 42e, 42f of the individual meandered electric heating means 40a, 40b, 40c, 40d, 40e, 40f are essentially parallel to each other.

[0107] The electric heating means 40a, 40b, 40c, 40d, 40e, 40f are resistive heating means, with the material of the electric heating means 40a, 40b, 40c, 40d, 40e, 40f selected from the group consisting of Iron (Fe), Chromium (Cr), Aluminium (Al), or combinations or alloys thereof.

[0108] The electric heating means 40a, 40b, 40c, 40d, 40e, 40f can be in the shape of coils, straight wires, straight strips, twisted strips, or combinations thereof, and one or more electrical connector(s) may be provided between a power supply and the electric heating means 40a, 40b, 40c, 40d, 40e, 40f on the side of or near a reactive mixture stream inlet 21 (cf. Fig. 3).

[0109] The electric heating means 40a, 40b, 40c, 40d, 40e, 40f are arranged in at least some of the hollow flow paths 313 of the macroscopic ceramic structure 32 (in Fig. 1 : in all hollow flow paths 313 of the macroscopic ceramic structure 32) in such way that at least 85 percent of the longitudinal extension or length of the electric heating means 40a, 40b, 40c, 40d, 40e, 40f are located within the respective hollow flow path 313. Fig. 3 illustrates an exemplary embodiment for a reactor system 100 provided for carrying out an endothermic reaction of the reactive mixture stream to be converted to the product gas.

[0110] According to Fig. 3, the reactor system 100 comprises

[0111] - the electrically heated structured ceramic catalyst 30, as exemplified with reference to Fig. 1 and as partly, namely in terms of the ceramic subunit 31 of the catalyst 30, more detailed in terms of preferred designs and / or shapes with reference to Fig. 2A (= first embodiment of subunit 31), to Fig. 2B (= second embodiment of subunit 31), and to Fig. 2C (= third embodiment of subunit 31), said catalyst 30 containing the electric heating means 40a, 40b, 40c, 40d, 40e, 40f extending in a meandered or meandering way (-> respective reference signs 41 a, 41 b, 41c, 41 d, 41 e, 41 f in Fig. 1 , summarised as reference sign 41 in Fig. 3) within the respective plane 42a, 42b, 42c, 42d, 42e, 42f forming in parallel installed electric heating elements (cf. Fig. 1), said electrical heating means 40a, 40b, 40c, 40d, 40e, 40f provided for heating a ceramic catalyst bed up to a predetermined reaction temperature, with two electric feeds 51 passing through the inlet section connected to an electric power supply 50 provided outside of the reactive mixture stream duct 20, said electric power supply 50 providing a potential difference AV;

[0112] - a pressure housing or pressure shell housing comprising reactive mixture stream inlets 21 for receiving the reactive mixture stream fed, a reactive mixture stream duct 20, a reactive mixture stream channel 23, a reactive mixture stream outlet 26, and the electrically heated structured ceramic catalyst 30; in other words, the structured ceramic catalyst 30 is hosted by said pressure (shell) housing, namely provided inside the reactive mixture stream duct 20 between the reactive mixture stream inlet 21 and the reactive mixture stream outlet 26; and

[0113] - a refractory layer between said structured ceramic catalyst 30 and said pressure (shell) housing wherein the pressure (shell) housing may house two or more of the structured ceramic catalysts 30 in series, so that the outlet stream of the first catalyst 30 enters into the inlet of the second catalyst 30, and - if applicable - so on.

[0114] As can also be taken from the exemplary embodiment shown in Fig. 3, a reactor shell 10 of the reactor system 100 comprises an insulation filling 11 at least partly encompassing the reactive mixture stream duct 20, and the ceramic catalyst bed is accommodated in a catalyst section 24, with the reactive mixture stream undergoing the catalytic reaction.

[0115] A heat exchange means 60 is provided between a preheating / mixing section 22 and a cooling section 25 to adequately transfer the heat of the exiting reactive mixture stream in the cooling section 25 to preheating / mixing section 22. The structural details of the reactive mixture stream, such as cross section, size and / or advancing path, may change depending on design requirements of specific applications.

[0116] The present invention has been disclosed for illustrative, non-limiting purposes, according to preferred embodiments thereof, but it has to be understood that any variations and / or any modifications can be made by the persons skilled in the art without for this reason escaping from the disclosure as well as from the protection scope, as defined in the enclosed claims.

[0117] List of reference signs

[0118] 10 reactor shell

[0119] 11 insulation filling

[0120] 20 reactive mixture stream duct

[0121] 21 reactive mixture stream inlet

[0122] 22 preheating / mixing section

[0123] 23 reactive mixture stream channel

[0124] 24 catalyst section

[0125] 25 cooling section

[0126] 26 reactive mixture stream outlet

[0127] 30 electrically heated structured ceramic catalyst

[0128] 31 ceramic subunit

[0129] 313 hollow flow path

[0130] 32 macroscopic ceramic structure

[0131] 40a first or highest electric heating means, assigned to first or highest plane 42a

[0132] 40b second electric heating means, assigned to second plane 42b

[0133] 40c third electric heating means, assigned to third plane 42c

[0134] 40d fourth electric heating means, assigned to fourth plane 42d

[0135] 40e fifth electric heating means, assigned to fifth plane 42e

[0136] 40f sixth or lowest electric heating means, assigned to sixth or lowest plane 42f

[0137] 41a meandered part or section of first or highest electric heating means 40a

[0138] 41 b meandered part or section of second electric heating means 40b

[0139] 41c meandered part or section of third electric heating means 40c

[0140] 41 d meandered part or section of fourth electric heating means 40d

[0141] 41 e meandered part or section of fifth electric heating means 40e

[0142] 41 f meandered part or section of sixth or lowest electric heating means 40f

[0143] 42a first or highest plane for first or highest electric heating means 40a

[0144] 42b second plane for second electric heating means 40b

[0145] 42c third plane for third electric heating means 40c

[0146] 42d fourth plane for fourth electric heating means 40d

[0147] 42e fifth plane for fifth electric heating means 40e

[0148] 42f sixth or lowest plane for sixth or lowest electric heating means 40f

[0149] 50 electric power supply

[0150] 51 electric feeds

[0151] 60 heat exchange means

[0152] 100 reactor system

[0153] AV potential difference of electric power supply 50

Claims

Claims1 . An electrically heated structured ceramic catalyst (30) for catalysing an endothermic reaction of a reactive mixture stream to be converted into a product gas, the catalyst (30) comprising at least one macroscopic ceramic structure (32) supporting a catalytically active material, enabling the conversion of the reactive mixture stream into the product gas and containing at least two electric heating means (40a, 40b, 40c, 40d, 40e, 40f), with at least some of, in particular each of, the electric heating means (40a, 40b, 40c, 40d, 40e, 40f) extending in a meandered or meandering way within at least one plane (42a, 42b, 42c, 42d, 42e, 42f) allocated or assigned to the respective electric heating means (40a, 40b, 40c, 40d, 40e, 40f), in particular with the planes (42a, 42b, 42c, 42d, 42e, 42f) being parallel to each other.

2. The structured ceramic catalyst according to claim 1 wherein the material of the macroscopic ceramic structure (32) is selected from the group consisting of SiC>2, AI2O3, Y2O3, WO3, ZrCk, TiO2, MgO, CaO, FeO2, ZnO2 and combinations thereof.

3. The structured ceramic catalyst according to claim 1 or 2 wherein the catalytically active material is selected from the group of d-block elements or combinations thereof, optionally including the addition of alkali, earth alkali and / or lanthanide elements.

4. The structured ceramic catalyst according to claim 3, with at least one of alkali, earth alkali and / or lanthanide elements added to the catalytically active material.

5. The structured ceramic catalyst according to at least one of claims 1 to 4 wherein the electric heating means (40a, 40b, 40c, 40d, 40e, 40f) are resistive heating means.

6. The structured ceramic catalyst according to at least one of claims 1 to 5 wherein the material of the electric heating means (40a, 40b, 40c, 40d, 40e, 40f) is selected from the group consisting of Iron (Fe), Chromium (Cr), Aluminium (Al), or combinations or alloys thereof.

7. The structured ceramic catalyst according to at least one of claims 1 to 6 wherein the electric heating means (40a, 40b, 40c, 40d, 40e, 40f) are in the shape of coils, straight wires, straight strips, twisted strips, or combinations thereof.

8. The structured ceramic catalyst according to at least one of claims 1 to 7 wherein the electric heating means (40a, 40b, 40c, 40d, 40e, 40f) are installed in at least some of hollow flow paths (313) of the macroscopic ceramic structure (32).

9. The structured ceramic catalyst according to claim 8 wherein at least 85 percent of the longitudinal extension or length of the electric heating means (40a, 40b, 40c, 40d, 40e, 40f) are located within the hollow flow path (313).

10. The structured ceramic catalyst according to at least one of claims 1 to 9 wherein the macroscopic ceramic structure (32) comprises, in particular consists of, at least two ceramic subunits (31), in particular with the macroscopic ceramic structure (32) formed from a multiplicity of juxtaposed subunits (31).11 . The structured ceramic catalyst according to claim 10 wherein the electric heating means (40a, 40b, 40c, 40d, 40e, 40f) are provided between the subunits (31) in the at least one plane (42a, 42b, 42c, 42d, 42e, 42f).

12. The structured ceramic catalyst according to claim 8 or 9 and to claim 10 or 11 wherein the subunit (31) is in the shape of a honeycomb, of a monolith, of a pellet, of a tube or of foam, in particular with the geometric shape of the subunit (31) being plate-like, for example embodied as an essentially two-dimensional arrangement, such as with the at least two hollow flow paths (313) succeeding in only one direction.

13. The structured ceramic catalyst according to at least one of claims 1 to 12 wherein at least one electrical connector between a power supply and the electric heating means (40a, 40b, 40c, 40d, 40e, 40f) is located on the side of or near a reactive mixture stream inlet (21).

14. A reactor system (100) for carrying out an endothermic reaction of a reactive mixture stream to be converted to a product gas, the reactor system (100) comprising a pressure housing that comprises at least one reactive mixture stream duct (20), a reactive mixture stream inlet (21) for receiving the fed reactive mixture stream, a reactive mixture stream outlet (26), the electrically heated structured ceramic catalyst (30) according to at least one of claims 1 to 13 provided inside the reactive mixture stream duct (20) between the reactive mixture stream inlet (21) and the reactive mixture stream outlet (26); an insulation filling (11) at least partly encompassing the reactive mixture stream duct (20), a ceramic catalyst bed accommodated in a catalyst section (24), with the reactive mixture stream undergoing a catalytic reaction, electrical heating means (40a, 40b, 40c, 40d, 40e, 40f) for heating the catalyst bed up to a predetermined reaction temperature; at least two electric feeds (51) passing through the inlet section connected to an electric power supply (50) provided outside of the reactive mixture stream duct (20).

15. A reactor system according to claim 14 wherein the pressure housing houses at least two of the catalysts (30) in series, so that the outlet stream of the first catalyst (30) enters in the inlet of the second catalyst (30).

Images