Plate element with indirect heating

Abstract

The present invention relates to a plate element with indirect heating as well as to a system, a module, a reactor and a method based on the plate element according to the invention.

Description

INERATEC GmbH Panel element with indirect heating AREA OF INVENTION

[0001] The present invention relates to a plate element with indirect heating as well as a system, module, reactor and method based on the plate element according to the invention. BACKGROUND

[0002] Plate reactors are used in chemical process engineering to carry out reactions that are difficult to scale and control. Exemplary and technically relevant reactions include CO methanation, Fischer-Tropsch (hereinafter also referred to as "FT") synthesis, and the reverse water-gas shift (rWGS) reaction. For FT synthesis and CO methanation, synthesis gas (a gas mixture comprising CO and H₂) is used as the starting mixture. To be able to describe the resulting products as "CO₂-neutral," one possible approach is to use CO₂ as the carbon source. One method for using CO₂ as a carbon source is the conversion of CO₂ with H₂ to CO and H₂O via an rWGS reaction.

[0003] All of the above-mentioned reactions are associated with a significant heat input and are generally carried out at elevated pressures of approximately 5 to 40 bar. To achieve the required high operating temperatures in the rWGS reaction, a considerable amount of energy must be introduced into the system, as this reaction is endothermic. This is typically achieved using heating elements acting directly in the fluid flow.

[0004] However, the presence of carbon-containing components (such as CO) can lead to undesirable coke formation in the reactor. For example, CO can form carbon and CO₂ via a disproportionation reaction (also known as the "Boudouard equilibrium"): 2 CO → CO₂ + C. Furthermore, CO can be reduced to carbon with hydrogen, forming water: CO + H₂ → H₂O + C (also known as "CO reduction"). Short-chain unsaturated compounds, especially ethylene and Propylene, which is present, for example, in FT recycling streams that can be added to a reactant stream for an rWGS reaction, also exhibits a problematic coke formation potential.

[0005] This often leads to a thin layer of coke depositing on the reactor components during operation, impairing the functionality of components located directly in the fluid flow, especially heating elements. This coke layer must be removed from time to time, sometimes in a very laborious process.

[0006] Direct heating elements, such as flow heaters, are generally difficult to clean due to their sometimes complex internal structure. This makes coke deposits on and in flow heaters particularly problematic and time-consuming (and therefore costly). Furthermore, direct heating elements are usually connected / wired within or in close proximity to the plate element, which can lead to undesirable coke formation at the electrically conductive connection points, potentially resulting in short circuits.

[0007] Furthermore, the heat transferred to a fluid by direct heating elements (i.e., heating elements that are directly in the fluid flow) is difficult to use for heating other structures or zones in the reactor, such as a reaction zone with a reaction catalyst. This is because the heat from the heating element can only be transferred indirectly to the reactor material via the flowing fluid, which has a comparatively low heat capacity (from where it could be transferred to other components / structures via thermal conduction).

[0008] Furthermore, heating elements that act directly in the fluid flow are external components that are integrated into the fluid flow and must be sealed to the outside to prevent fluid leakage through any leaks at the connection ends of the heating element as much as possible. This is both complex and, due to the extreme conditions typically found in the reactor (very high temperatures and pressures), usually not completely possible. Fluid leakage through potential leaks at the directly acting heating element cannot generally be completely prevented. SUMMARY OF THE INVENTION

[0009] It is an object of the invention to provide a plate element for the construction of a plate reactor in which the aforementioned disadvantages do not occur or only occur to a reduced extent.

[0010] In particular, it is an object of the invention to provide a plate element in which the aforementioned coking problems are not present or are only present to a reduced extent. Extent occurs and at the same time an efficient and controlled heat input into the fluid to be heated takes place.

[0011] Furthermore, it is an object of the invention to minimize or prevent unwanted fluid leakage through any leaks.

[0012] It was surprisingly discovered that this task is solved wholly or partly by the plate element described in the claims, as well as by the system, module, reactor and method described in the claims.

[0013] In particular, it was found that the use of indirect heating elements (i.e., heating elements where heat is transferred indirectly, via thermal conduction, through the material of the plate element to the fluid to be heated) leads to improved heat transfer compared to direct heating elements (i.e., heating elements where heat is transferred through direct physical contact of the heating element with the fluid to be heated).

[0014] Furthermore, it was found that heat can be efficiently transferred via thermal conduction into any existing reaction zone to carry out an endothermic reaction, in particular a rWGS reaction. Thus, the heat provided by the heating elements can be used not only to heat the fluid flow but also efficiently to carry out an endothermic chemical reaction in a reaction zone.

[0015] As described in detail below, such a reaction zone for carrying out an endothermic chemical reaction can be provided in a further plate element, which is arranged adjacent to the plate element according to the invention. Within the scope of the present application, such a further plate element is also referred to as a "reaction plate element".

[0016] Furthermore, it has been shown that indirect heating elements are far less affected by coking problems compared to direct heating elements, especially with regard to the electrical leads.

[0017] Furthermore, it was found that by separately and grouping a large number of indirectly acting heating elements at specific positions along an adjacent reaction zone, a homogeneous reaction temperature can be achieved along the entire reaction zone, despite the inflow of colder gas and the varying heat requirements of the reaction as it progresses. This is advantageous for the conversion and selectivity of the rWGS reaction and is difficult to achieve with directly acting heating elements.

[0018] A first aspect of the invention relates to a plate element for constructing a plate reactor according to claim 1.

[0019] A second aspect of the invention relates to a system comprising the plate element according to the invention and six or more heating elements, each of which is arranged in recesses of the plate element.

[0020] A third aspect of the invention relates to a reactor module for the production of synthesis gas, comprising a plate element or system according to the invention, as well as a reaction plate element comprising a reaction zone for receiving a catalyst.

[0021] A fourth aspect of the invention relates to a reactor for the production of synthesis gas, comprising a plurality of the reactor modules according to the invention.

[0022] A fifth aspect of the invention relates to a method for carrying out a chemical reaction, characterized in that the method is carried out in a reactor according to the invention and that a fluid flowing through one or more fluid channels is heated by means of heat conduction through at least six heating elements. FIGURES Figs. 1A and 1B show a plate element according to the invention. Fig. 1C shows an enlargement of a section of Fig. 1B to illustrate the height of the plate element (“h”) and the height of the half-plate element (“H”). Fig. 2 shows a half-plate element from two perspectives. Fig. 3 shows an enlargement of the recesses in the half-plate element. Fig. 4 shows the determination of the heating zone length. Fig. 5 shows a section of a reactor according to the invention. Fig. 6 shows an enlargement of area A of figure 5. Fig. 7 shows the influence of the height of the half-plate elements with semi-cylindrical recesses in example 3. Fig. 8 shows the temperature profile in the heated gas before and between heating elements in Example 3. Fig. 9 shows the set power per heating cartridge in example 3. Fig. 10 shows a detailed analysis of the temperature increase at the first heating cartridge in example 3. DETAILED DESCRIPTION OF THE INVENTION

[0023] The present invention is based, at least in part, on the finding that indirect heating elements offer a number of advantages over direct heating elements commonly used in the prior art. The claimed arrangement of heating elements is also advantageous compared to indirect heating elements known from the prior art.

[0024] In particular, the present invention is based on the finding that indirectly acting heating elements transfer heat to a total system of fluid to be heated and reaction zone to be heated far more efficiently than heating elements acting directly in the fluid flow and also exhibit a significantly lower coking problem.

[0025] Furthermore, the present invention is based on the finding that an undesirable escape of fluid through leaks in the reactor can be significantly reduced by using indirectly acting heating elements (which do not come into direct physical contact with the fluid to be heated) instead of directly acting heating elements.

[0026] Furthermore, the present invention is based on the finding that a heat load profile or a temperature profile can be imposed in a particularly simple manner by separately and groupedly controlling a plurality of indirectly acting heating elements with at least two groups at specific positions along an adjacent reaction zone. This allows an adapted or homogeneous reaction temperature to be achieved along the reaction zone despite the inflow of colder gas and the varying heat requirements of the reaction as the reaction progresses. Moreover, when the catalyst is deactivated over its lifetime, the power demand can be shifted to the zone of the catalyst where the (still) active zone of the catalyst is located during active operation.

[0027] The following definitions, among others, apply within the scope of this disclosure:

[0028] For the purposes of the present invention, an "indirectly acting heating element" describes a heating element that transfers heat indirectly, by means of thermal conduction, via a material of the plate element to the fluid to be heated. An indirectly acting heating element therefore does not come into direct physical contact with a fluid flowing through the plate element.

[0029] An indirect heating element is spatially separated from a fluid flowing through the plate element, particularly by the material of the plate element.

[0030] To heat a fluid flowing through the plate element, the indirectly acting heating element first heats the surrounding material of the plate element, which then transfers the heat to the fluid flowing past it.

[0031] In this context, "fluid flowing through the plate element" refers to a fluid that flows through the plate element along the path intended for this application. Fluid that flows through leaks in the reactor (for example, due to high pressure) and thus potentially comes into direct contact with the indirectly acting heating element is disregarded. Therefore, the intended fluid path is the sole determining factor for classifying it as an indirectly acting heating element. A person skilled in the art can determine the intended fluid path based on the structure and arrangement of the fluid-conducting elements.

[0032] Preferred indirect heating elements are heating cartridges that can be inserted into designated recesses in the plate element (e.g., bores).

[0033] In contrast, a "direct-acting heating element" describes a heating element that transfers heat to the fluid being heated through direct physical contact. For this to occur, the fluid to be heated flows directly past (i.e., in direct physical contact with) or through the direct-acting heating element. Direct-acting heating elements are therefore placed directly into the fluid flow. An example of a direct-acting heating element is a flow-through heater.

[0034] For the purposes of the present invention, “fluid-conducting structures” are structures in the plate element through which a fluid flows or can flow during proper operation of the reactor.

[0035] Exemplary fluid-conducting structures include at least one inlet opening, one or more fluid channels, and also a reaction zone optionally provided in the plate element, through which a fluid flows and undergoes a chemical reaction. Here, too, the intended fluid path through the plate element is the sole determining factor. Any leaks through which a fluid can flow due to high applied pressure, contrary to the intended operation, are therefore not fluid-conducting structures within the meaning of the present invention.

[0036] For the purposes of the present invention, "materially connected" or "being materially connected" means that a fluid can flow unhindered into interconnected elements, for example, from a fluid channel into a zone or vice versa. Here, too, the intended fluid path is crucial, or rather, the possibility that a fluid can flow along this fluid path during normal operation.

[0037] For the purposes of this disclosure, “thermally connected” or “in thermal connection” means that heat energy can (also) be transferred by thermal conduction (i.e., by heat transport via solids in mechanical contact, in particular mediated by phonons and electrons), for example from a heating element to a reaction zone, from a heating element to a fluid, from one or more fluid channels to another fluid channel or fluid channels, or from one zone to another zone.

[0038] In addition to heat transfer by conduction, as is the case here for "thermally connected" components, heat transfer can also occur by diffusion / forced convection and / or radiation. While these types of heat transfer can occur in addition to conduction, they do not fall under the term / feature "thermally connected" as defined in this disclosure.

[0039] In preferred embodiments, "thermally connected" means that areas of the reactor are thermally connected to one another in such a way that a thermal conductivity of 5 W / mK to 20 W / mK at 20°C is achieved, preferably 8 W / mK to 16 W / mK at 20°C, more preferably 10 W / mK to 15 W / mK at 20°C and / or 10 W / mK to 50 W / mK at 800°C, more preferably 15 W / mK to 40 W / mK at 800°C, and more preferably 20 W / mK to 35 W / mK at 800°C. These thermal conductivities allow for efficient heat transfer.

[0040] The term "in the direction of flow," as used throughout this disclosure, refers to the fluid path through the plate element during operation according to the invention. This means that if component X is arranged in the direction of flow towards component Y, a fluid flowing through the reactor first reaches component Y and then component X. The fluid path through the reactor is evident to those skilled in the art even without a gas flowing through the reactor, namely from its structure alone. In particular, it is known to those skilled in the art that the fluid flows into the plate element through the at least one inlet opening and flows through the fluid channels. The fluid path results from the structural and geometric design of the fluid-conducting structures.

[0041] "Downstream" means (in relation to the fluid path through the reactor) in the direction of flow. "Downstream of" means (in relation to the fluid path through the reactor; not geometrically) "towards".

[0042] "Upstream" means (in relation to the fluid path through the reactor) against the flow direction. "Upstream of" means (in relation to the fluid path through the reactor; not geometrically) "before".

[0043] Within the scope of this invention, a "recess" refers to a specific type of indentation, namely a structure open in a direction away from the plate element that does not completely penetrate the plate element (comparable to a pool or a river). For operation of the reactor, the outwardly open side (away from the plate element) of the recess is closed, preferably by placing another plate element on top of it.

[0044] Within the scope of this invention, the term "heating zone length" refers to the maximum distance between two points in the two recesses furthest apart from each other (see Fig. 4).

[0045] Within the scope of this disclosure, the terms "gas" (stream) and "fluid" (stream) are used interchangeably and equivalently. At the comparatively high temperatures relevant here, all reaction components will typically be present in the gas phase. However, this is not contradicted for those skilled in the art by the fact that components, for example water vapor, may also be present at least partially or in sections as a liquid.

[0046] Preferably, the fluid is a gas.

[0047] A first aspect of the invention relates to a plate element for constructing a plate reactor. "For constructing a plate reactor" means that the plate element according to the invention is suitable, together with other plates, to form a plate reactor.

[0048] The plate element according to the invention has a maximum length “I” and a maximum width “b” as well as a maximum height “h” and is characterized in that the following applies: I > 3 b, preferably I > 5 b, further preferred I > 10 b, and — > 50 n The length of the plate element is therefore at least three times its width, preferably at least five times, and more preferably at least ten times. The ratio of the maximum length "I" of the plate element to the maximum height "h" of the plate element is at least 50.

[0049] The plate element has six or more recesses, each designed to accommodate a heating element.

[0050] The plate element according to the invention further comprises at least one inlet opening for a fluid and one or more fluid channels. The plate element In preferred embodiments, it has further structures, in particular a reaction zone and / or at least a heating zone.

[0051] The plate element according to the invention is further characterized in that the six or more recesses (which serve to accommodate heating elements) are not in material contact with the one or more fluid channels, nor with the at least one inlet opening, nor with any other fluid-conducting structures that may be present in the plate element, in particular with reaction zones optionally provided in the plate element.

[0052] This feature means that, during intended operation of the reactor, no fluid flows through the six or more recesses (in which heating elements are located during reactor operation) and thus no fluid comes into direct physical contact with the heating elements located in the recesses. This feature therefore characterizes indirect heating of a fluid flowing through the plate element according to the invention. The heating elements located in the recesses are thus indirectly acting heating elements. Here, too, only the intended fluid path through the plate element is relevant.

[0053] As mentioned above, the use of indirect heating elements (i.e., heating elements that do not come into direct physical contact with a fluid flowing through the reactor when the reactor is operating properly) leads to a number of advantages.

[0054] Firstly, indirectly acting heating elements lead to more efficient heat transfer to a fluid flowing through the plate element according to the invention. Without being bound to a specific theory, it is assumed that this is due to the fact that a comparatively large part of the plate element is heated and the heat is transferred to the fluid to be heated via thermal conduction and a large surface area. The temperature difference between the heated surface and the fluid to be heated can therefore be kept small.

[0055] Secondly, removing the heating elements from the fluid flow effectively protects them against coke deposits.

[0056] Furthermore, the use of indirect heating elements largely eliminates the need for additional external components in the fluid path, thereby reducing the number of potential leaks in the plate element. It was also found that separate, grouped control of numerous indirect heating elements at specific positions along an adjacent reaction zone maintains a homogeneous reaction temperature along the entire zone, despite the inflow of colder gas and the varying heat requirements of the reaction as it progresses. The reaction zone can be reached. This is advantageous for the conversion and selectivity of the reaction and is difficult to achieve with direct-acting heating elements.

[0057] As described above, the plate element according to the invention has both recesses for receiving heating elements and fluid channels. This is particularly advantageous compared to systems in which heating elements and fluid channels are located in separate plate elements. One advantage is a more compact and less failure-prone design. Furthermore, this design results in very good heat transfer into the fluid channels. Additionally, this design typically requires fewer plate elements overall, which reduces the number and likelihood of potential leaks between plate elements.

[0058] The six or more recesses preferably each have a longitudinal axis. Preferably, the longitudinal axes of the recesses are arranged substantially parallel to the width of the plate element. "Substantially parallel" in this case means parallel to each other by ± 5°, preferably by ± 2°.

[0059] The ratio of the maximum length “I” of the plate element to the maximum height “h” of the plate element is at least 50. In a preferred embodiment, the ratio of the maximum length “I” of the plate element to the maximum height “h” of the plate element is at least 70, preferably at least 100.

[0060] Preferably, the maximum length of the plate element is 50 cm to 5 m, more preferably 1 m to 3 m, and more preferably 1 m to 2 m. The maximum width of the plate element is preferably 5 cm to 100 cm, more preferably 10 cm to 60 cm, and more preferably 20 cm to 50 cm.

[0061] The maximum height of the plate element is preferably 10 to 40 mm, more preferably 16 to 30 mm, more preferably 16 to 24 mm, more preferably 18 to 22 mm.

[0062] According to a preferred embodiment, the six or more recesses have a maximum diameter and a length, wherein the length is at least five times the maximum diameter, preferably at least ten times the maximum diameter. Preferably, the maximum diameter varies by less than 10%, more preferably less than 5%, and more preferably less than 3% over the entire length.

[0063] According to one embodiment, the six or more recesses are not provided on the surface of the plate element, but are located inside the plate element. Or in other words, according to one embodiment, the six or more recesses are located inside the plate element. This means that the recesses are surrounded by the material of the plate element (or by the material of two half-plate elements). Openings for inserting heating elements into the These cutouts are naturally not surrounded by the material of the panel element. Such cutouts can also be described as "holes" in the panel element. These "holes" can even penetrate the panel element completely.

[0064] Preferably, the recesses are arranged one after the other in the direction of flow. This means that a fluid flowing through the plate element passes the recesses successively, first the recess furthest upstream and last the recess furthest downstream.

[0065] According to one embodiment, the plate element according to the invention has a cuboid shape with a maximum length "I", a maximum width "b", and a maximum height "h", wherein the height is smaller than both the length and the width. The length denotes the longest dimension of the plate element, and the height denotes the shortest dimension. "Cuboid shape" in this context means a shape having six faces, each pair of which is substantially parallel to one another. "Substantially parallel" also means parallel ± 5° to each other, preferably ± 2°. It is understood that certain geometric deviations from a perfect cuboid shape are tolerated, as long as a cuboid shape is fundamentally recognizable.Deviations include, for example, rounded corners, and / or a convex and / or concave design of the corners and / or cuboid sides, and / or manufacturing-related imperfect parallelism of opposite cuboid sides, and / or structured side surfaces.

[0066] According to one embodiment, the plate element according to the invention is in the form of a structured plate, i.e. a plate into which structural elements are introduced by removing plate material.

[0067] According to a further preferred embodiment, the plate element according to the invention is composed of two separably connected half-plate elements. The two separably connected half-plate elements together form the plate element according to the invention. Preferably, the two separably connected half-plate elements are screwed together. The advantage of this embodiment is that the plate element according to the invention can be easily disassembled and reassembled for cleaning or maintenance work.

[0068] Preferably, the plate element can be separated into two half-plate elements by dividing it along a central plane. The central plane preferably extends through the six or more recesses.

[0069] Preferably, the six or more recesses are defined by the two half-plate elements. This means that the six or more recesses are located between the two half-plate elements.

[0070] According to a preferred embodiment, the two half-plate elements are counterparts, i.e., mutually functionally complementary half-plate elements, and each has half-plate element recesses that are arranged opposite each other in the plate element and together form the six or more recesses.

[0071] Preferably, the half-plate element recesses are designed in a semi-cylindrical shape, and two half-plate elements together form cylindrical recesses in the plate element.

[0072] In this context, "cylindrical" means a geometric shape characterized by a substantially circular cross-section with a maximum diameter that remains substantially constant along the entire length. Cylindrical recesses thus have a length and a maximum diameter. "Substantially circular cross-section" means that the cross-section need not be perfectly circular but can also be oval. "A maximum diameter that remains substantially constant along the entire length" describes a maximum diameter that varies by less than 10%, preferably less than 5%, and more preferably less than 3%, along the entire length. As described above, the length is preferably at least five times the maximum diameter and more preferably at least ten times the maximum diameter.

[0073] In this context, "semicylindrical" refers to a structure obtained by dividing a cylinder longitudinally along a plane into two parts, specifically two essentially equal parts. "Essentially equal parts" in this context means two parts (i.e., halfcylinders) whose volumes differ by no more than 25%. If the dividing plane passes through the central axis of the cylinder, the result is two identical halfcylinders.

[0074] Preferably, all recesses for receiving a heating element have the same geometry. Or in other words: preferably, all recesses for receiving a heating element are identically designed.

[0075] The inventors of this invention have found that faster temperature rise and / or better temperature control can be achieved when the distance between adjacent recesses is small. In particular, the inventors of this invention have found that faster temperature rise and / or better temperature control can be achieved when the distance between adjacent recesses is no greater than twice the diameter of the recesses.

[0076] In a preferred embodiment, the distance between adjacent recesses is therefore no more than twice the diameter of the recesses.

[0077] It is preferred that at least one of the half-plate elements is characterized in that half-plate element recesses are provided on one side of the The recesses in the half-plate element are arranged in a single plate, and fluid channels are arranged, preferably exclusively, on the opposite side of the half-plate element. Preferably, both half-plate elements are configured in this way. It is understood that the recesses in the half-plate element arranged on one side and the fluid channels arranged on the opposite side are not in material contact.

[0078] A half-plate element with half-plate element recesses on one side and fluid channels on the opposite side is shown in Fig. 2, wherein half-plate element recesses are milled into one side surface of the half-plate element and fluid channels are milled into the opposite side surface of the half-plate element.

[0079] Preferably, the recesses in the half-plate element are arranged on one side and the fluid channels on the opposite side of the half-plate element. This ensures a small distance between the heating elements (which are arranged in the recesses during operation) and the fluid channels, and thus good heat transfer into the fluid.

[0080] One-piece, inseparable plate elements are also referred to as "plate elements" within the meaning of the present invention. The advantage of this embodiment is a robust construction and the reduction of potential leakage. Within the scope of the present invention, two welded half-plate elements are also understood to be a one-piece plate element.

[0081] According to one embodiment, the recesses are formed in the form of bores in the plate element. Such recesses can also be described as holes drilled into the plate element. This embodiment is shown in Figures 5 and 6.

[0082] The above general statements also apply to this embodiment. For example, it is also the case that, preferably, all recesses for receiving a heating element have the same geometry.

[0083] Furthermore, for this embodiment as well, the distance between adjacent recesses preferably does not exceed twice the diameter of the recesses.

[0084] According to a preferred embodiment, the plate element according to the invention has two opposing side surfaces, the longest dimension of which corresponds to the width “b” of the plate element, wherein the six or more recesses are arranged in a continuous region of the plate element that comprises a maximum of 30% of the length of the plate element plus one of the aforementioned side surfaces. For the purposes of this invention, the “dimensions” of a surface are understood to be length, width, and height; the diagonal is not a “dimension” of a surface.

[0085] This "maximum 30% of the (total) length" criterion means that if the side surface encompassed by the continuous area describes the underside of the plate element and the other, opposite side surface describes the top of the plate element, then the six or more cutouts are located in the lower 30% of the plate element. Therefore, it is also referred to below that the cutouts are located in the lower 30% of the plate element. This is illustrated in Figure 2. On the side with the cutouts, the cutouts are located in the lower 30% of the plate element.

[0086] The at least one entry opening is preferably located near the top of the plate element, i.e. adjacent to the side surface that is not included in the area where the six or more recesses are located.

[0087] The six or more recesses are therefore preferably located at the end of the plate element opposite the at least one entrance opening.

[0088] According to a preferred embodiment, each recess has one or two, preferably two, openings. It is understood that the opening(s) is / are designed such that a heating element can be inserted into the respective recess(s) through at least one of the opening(s).

[0089] Preferably, the opening(s) is / are arranged laterally on the plate element. In the case of cylindrical recesses, the opening(s) correspond to the base area(s) of the cylinder.

[0090] In an embodiment comprising two separably connected, preferably screwed, half-plate elements that together form the plate element, each recess preferably has one or two openings designed such that a heating element can be inserted through the opening(s) into the respective recesses without (needing to) separate the two separably connected half-plate elements. This ensures particularly easy handling and installation of heating elements on the plate element.

[0091] This also applies, of course, if the recesses are designed as bores, especially in a one-piece plate element.

[0092] According to a preferred embodiment, at least one recess, or at least two, four or six recesses, preferably all recesses, extend through the entire width of the plate element, wherein at least one, two, four, six or all recess(s) each have two openings arranged opposite each other.

[0093] Preferably, what is stated in the preceding paragraph applies to all recesses.

[0094] This arrangement allows the heating elements, which are provided in the recesses, to protrude laterally from both openings of the recesses. This means that the electrical connections of the heating elements, which are preferably located at opposite ends of the heating elements, can be situated outside the plate element and at a certain distance from it. In this way, the potential for coking at the electrical connections of the heating elements can be significantly reduced.

[0095] The reason for coke formation, even at electrical connections, is that during operation of a reactor or plate element, the extreme conditions (temperatures and pressures) generally make it impossible to completely prevent fluid from escaping the plate element. Therefore, a certain potential for coke formation exists even outside the plate element due to the escaping fluid and the high temperatures (especially in the area of ​​the heating elements). However, the potential for coke formation due to the Boudouard reaction and CO reduction decreases with decreasing temperature and is comparatively low at temperatures of 400 °C and below. This is because, while there is a high potential for coke formation up to a temperature of 400 °C, the kinetics of coke formation are slow. Thus, the interplay of thermodynamics and kinetics results in comparatively low coke formation at temperatures up to 400 °C.

[0096] It is therefore advantageous overall that the heating elements protrude from the openings to such an extent that the electrical connections (which are preferably located at the ends of the heating elements) are located outside the reactor in an area where a temperature of 400 °C or less prevails.

[0097] According to a preferred embodiment, the plate element has 4 to 18 recesses, preferably 6 to 18, more preferably 6 to 15, and even more preferably 9 to 12.

[0098] The advantage of these designs lies in the simple and efficient grouping of heating elements located in recesses. For example, with six recesses, two circuits with three heating elements each can be provided. With nine recesses, three circuits with three heating elements each can be provided.

[0099] As described above, the recesses are preferably located in the lower 30% of the plate element.

[0100] As already described, the recesses are preferably essentially cylindrical in shape. Preferably, the recesses are cylindrical and each has a longitudinal axis.

[0101] According to a preferred embodiment, the longitudinal axes of the recesses are arranged essentially parallel to each other (i.e., parallel ± 5° to each other, preferably ± 2°).

[0102] According to a particularly preferred embodiment, the longitudinal axes of the recesses are arranged essentially parallel (i.e. parallel ± 5° to each other, preferably ± 2°) to the width of the plate element.

[0103] According to a preferred embodiment, the longitudinal axes of the recesses are arranged substantially perpendicular to the flow direction of the fluid in the plate element. "Substantially perpendicular" means an orientation of 90° ± 5°, preferably ± 2°, relative to each other.

[0104] According to a further preferred embodiment, the fluid channels each have a longitudinal axis that is arranged substantially perpendicular to the longitudinal axis of the recesses. Here too, "substantially perpendicular" means an orientation of 90° ± 5°, preferably ± 2°, relative to each other.

[0105] Preferably, the plate element has a plurality of adjacent fluid channels, each with a maximum depth of 0.5–4.0 mm, more preferably 0.5–3.0 mm, more preferably 0.5–2.5 mm, and more preferably 0.5–2.0 mm. The maximum cross-sectional length of the fluid channels is preferably 8 to 50 mm.

[0106] Fluid channels do not have to have a round cross-section, but can have any geometric cross-section, e.g. oval, square, round.

[0107] Preferably, the fluid channels are designed as recesses. This means that the fluid channels are preferably located on one side of the plate element and are open at the top.

[0108] For the construction and operation of a reactor, the upwardly open side of the fluid channels is closed. For this purpose, a further plate element is preferably arranged on the plate element according to the invention, so that the fluid channels are located between these two plate elements and are defined by them.

[0109] Preferably, the open ends of the one or more fluid channels through which fluid flows out of the plate element define outlet openings. Preferably, the one or more fluid channels have open ends on the side surface whose longest dimension corresponds to the width "b" of the plate element and which is encompassed by the connected area that includes the recesses. Or, in other words: While the at least one inlet opening is preferably located at the upper end of the plate element, one or more outlet openings are preferably located at the lower end of the plate element. Fluid thus preferably flows at one end of the into the plate element and out of the plate element at the other end of the plate element.

[0110] Preferably, the six or more recesses are arranged opposite (in the top view of the plate element) a part of the fluid channels.

[0111] Preferably, the distance between opposing recesses and fluid channels is as short as possible. In one embodiment, the smallest distance between a recess and the opposing fluid channels is no more than 4 mm, and more preferably no more than 3 mm. "Smallest distance" refers to the spatial distance. The "smallest distance" thus indicates the shortest distance in space between a point in a recess and a point in a fluid channel. This ensures optimal heat transfer (by conduction) from the heating elements arranged in the recesses, through the material of the plate element, into the fluid flowing through the fluid channels.

[0112] According to a preferred embodiment, the plate element further comprises a reaction zone for receiving a catalyst. The reaction zone is preferably provided as a recess with one or more reaction zone inlet openings and one or more reaction zone outlet openings in the plate element.

[0113] In one embodiment, the reaction zone is designed as a depression. The depression can be easily loaded with a catalyst via the (before assembly) upward-facing side.

[0114] In one embodiment, the length of the reaction zone is 2-20% of the length of the plate element, preferably 4-12%.

[0115] The width of the reaction zone is preferably 80-95% of the width of the plate element.

[0116] In one embodiment, the reaction zone has a length of 5-15 cm, preferably 6-13 cm. According to a preferred embodiment, the reaction zone has a length of 3-7 cm, preferably 4-6 cm. According to another preferred embodiment, the reaction zone has a length of 7-13 cm, preferably 8-12 cm.

[0117] Preferably, the reaction zone is located adjacent to, but not opposite, the six or more recesses. This means that the reaction zone is preferably not located in a continuous area of ​​the plate element that comprises a maximum of 30% of the length of the plate element plus one of the aforementioned side faces. Or, in other words, the reaction zone is preferably not located in the lower 30% of the plate element.

[0118] Preferably, the shortest distance between the recess closest to the reaction zone and the reaction zone is at least 5 mm, preferably at least 6 mm, more preferably at least 7 mm, and even more preferably at least 8 mm.

[0119] According to one embodiment, the reaction zone divides the fluid channels into at least two sets of fluid channels, comprising one set of fluid channels between the at least one inlet opening and the reaction zone, and one set of fluid channels downstream of the reaction zone. Preferably, in this embodiment, the set of fluid channels located downstream of the reaction zone is situated opposite (when viewed from above the plate element) the six or more recesses. Preferably, the reaction zone is a hydrogenation reaction zone for the inclusion of a hydrogenation catalyst. The hydrogenation reaction zone serves to form an at least partially hydrogenated fluid stream. During reactor operation, a hydrogenation reaction takes place in the hydrogenation reaction zone (equipped with a hydrogenation catalyst), resulting in the formation of an at least partially hydrogenated fluid stream. "At least partially hydrogenated" means that not every component of the fluid stream that is in principle accessible to hydrogenation needs to be hydrogenated in the hydrogenation reaction, and that those components that are hydrogenated do not need to be converted quantitatively. Preferably, if present, at least olefins with a carbon number less than 10, preferably 5, and more preferably 3, and CO are at least partially hydrogenated or reduced.Preferably, more than 50%, and more preferably more than 80%, of the olefins and less than 50%, and more preferably less than 80%, of the CO present in the fluid stream before entering the hydrogenation reaction zone are hydrogenated or reduced within the hydrogenation reaction zone. While the hydrogenation of the olefins is maximized, a low conversion of CO to methane is desirable in principle, as this is sufficient to suppress side reactions by CO, thus preventing an excessive reduction in the chemical energy content of the gas mixture. By hydrogenating potentially coke-forming olefins and CO, coke deposits on downstream structures and components can be significantly reduced. Percentage values ​​for the composition of fluid flows within the scope of this disclosure are given in mol%, unless otherwise specified in a particular embodiment.

[0120] It should be clarified that the reaction zone (preferably a hydrogenation reaction zone) that may be present in the plate element according to the invention and the reaction plate element reaction zone present in an adjacent reaction plate element (see third aspect) are The plate element contains different reaction zones. Since the reaction zone present in the plate element according to the invention is preferably used to carry out a hydrogenation reaction (which is exothermic) with a hydrogenation catalyst, heat transfer into this reaction zone is usually undesirable. This can be achieved by a certain spatial separation of the reaction zone from the heating elements (and thus also by recesses). Therefore, preferably, as described above, the shortest distance between the recess closest to the reaction zone and the reaction zone is at least 5 mm, preferably at least 6 mm, more preferably at least 7 mm, and even more preferably at least 8 mm. In contrast, the reaction zone of the reaction plate element (i.e., the reaction zone provided within the reaction plate element) is preferably intended for carrying out an endothermic chemical reaction (in particular, a rWGS reaction) (see third aspect). Heat conduction from the heating elements to the reaction zone of the reaction plate element is therefore desirable. In this way, the heat provided by the heating elements can be used not only to heat the fluid flow but also efficiently to carry out an endothermic chemical reaction in the reaction zone of the reaction plate element. For this reason, the shortest distance between the recess closest to the reaction zone of the reaction plate element and the reaction zone itself is preferably no more than 4 mm.

[0121] According to a preferred embodiment, the plate element is characterized in that it is configured to operate at temperatures above 600 °C, preferably above 700 °C.

[0122] Preferably the plate element contains, and more preferably consists of, a metal or a metal alloy.

[0123] Preferably, this alloy is a high-temperature resistant steel. This steel is preferably chemically stable and, in particular, resistant to carbon incorporation (metal dusting). Suitable exemplary steels are known as Alloy 800 H / HT, Inconel CA 602, Inconel 693, or under the DIN designations 2.4633 or 1.4876, as well as Alloy 601, Alloy 690, Alloy 693, and Alloy 699 XA. The steel may also be at least partially coated with aluminum, water glass, or tin to increase its resistance to metal dusting.

[0124] A second aspect of the invention relates to a system comprising the plate element according to the invention and six or more heating elements, preferably 6 to 18 heating elements, more preferably 6 to 15, and even more preferably 9 to 12, each of which is arranged in the recesses of the plate element.

[0125] Preferably, the heating elements are either individually or as a subset of the total number of heating elements, and their temperature can be controlled. This allows for the grouped control of a large number of indirectly acting heating elements at predetermined positions. This makes it possible, for example, to achieve a homogeneous reaction temperature along a reaction zone located in a reaction plate element adjacent to the plate element according to the invention. This is advantageous for the conversion and selectivity of the reaction and is less easily achieved with directly acting heating elements.

[0126] Preferably, the heating elements are cartridge heaters. The cartridge heaters are preferably electrically connected at both ends. This means that each of the two opposite ends of the cartridge heaters is connected to a connecting wire. The advantage over an embodiment with two connecting wires at one end of the cartridge heater is that the spatial separation of the connecting wires minimizes the risk of short circuits.

[0127] According to a preferred embodiment, the heating elements project laterally from the plate element on at least one side, preferably from both sides. Preferably, the heating elements project from the plate element by at least 10% of their total length, more preferably by at least 20% of their total length.

[0128] The technical advantage of this embodiment has already been described above: This results in the electrical connections of the heating elements being located outside the plate element and at a certain distance from it. In this way, the potential for coking at the electrical connections of the heating elements can be significantly reduced.

[0129] According to a preferred embodiment, the heating elements are electrically connected at their two opposite ends outside the plate element; that is, the heating elements each have electrically conductive leads at their two opposite ends outside the plate element. The advantage associated with this has also been described above.

[0130] According to a preferred embodiment, the system further comprises a control unit for setting different temperatures in two or more different subgroups of three heating elements each along the length of the plate element.

[0131] According to a preferred embodiment, the system is designed such that heat is transferred from a heating element to a fluid flowing through one or more fluid channels via a solid material of the plate element with a heat transfer coefficient of more than 250 W / (m²). 2 K) and / or a heat flow of more than 550 W.

[0132] According to one embodiment, the plate element further comprises a reaction zone (as described in the first aspect) in which a catalyst is arranged.

[0133] A third aspect of the invention relates to a reactor module for the production of synthesis gas. The reactor module comprises a plate element or system according to the invention, and a reaction plate element comprising a reaction zone for receiving a catalyst. The reaction plate element is distinct from the plate element.

[0134] Preferably, the plate element is separable and thermally conductively connected to the reaction plate element.

[0135] According to a preferred embodiment, the recesses of the plate element according to the invention and the reaction plate element reaction zone are arranged at least partially opposite and overlapping, preferably such that the entire reaction zone is opposite the zone with recesses of the plate element according to the invention. This ensures a short distance between the recesses / heating elements in the plate element according to the invention and the reaction plate element reaction zone in the adjacent reaction plate element, and thus efficient heat transfer from the heating elements via the material of the plate element into the reaction plate element reaction zone of the reaction plate element. This is a significant advantage over heating elements acting directly in the fluid flow.

[0136] The shortest distance between the recess closest to the reaction plate element reaction zone and the reaction plate element reaction zone is preferably at most 4 mm.

[0137] In a preferred embodiment, the heating zone length is 110% to 150% of the maximum length of the reaction plate element reaction zone. This ensures good heat transfer into the reaction plate element reaction zone as well as sufficient preheating of the fluids that are directed to the reaction zone via the heating elements.

[0138] The plate element according to the invention and the reaction plate element are preferably arranged directly adjacent to each other.

[0139] Plate elements arranged directly adjacent to one another are preferably sealed against each other. While this cannot completely prevent fluid leakage, especially not at all pressures, it does minimize fluid leakage from the reactor by sealing them against each other.

[0140] In a preferred embodiment, the immediately adjacent plate elements are sealed against each other by a sealing element. The choice of the sealing element is not limited in principle, as long as it is temperature-resistant and chemically inert to the fluid flows present in the reactor.

[0141] In one embodiment, the sealing element is made of a temperature-resistant material. "Temperature-resistant" within the meaning of the present invention means that the elements or components are not, or not significantly, impaired in their functionality when the reactor is operated at the specified upper temperature limits. In one embodiment, the sealing element comprises or consists of mica, one or more fibrous minerals, or graphite. These sealing elements are reversible, meaning they can be removed without damaging a plate element. This allows for easy disassembly of the plate reactor for maintenance or repair purposes.

[0142] The sealing elements seal the plate elements arranged immediately adjacent to each other and, during operation according to the invention, minimize unwanted fluid leakage from the reactor (also referred to as "mass loss"). However, unwanted fluid leakage cannot usually be completely prevented, so that fluid is also present outside in the vicinity of the reactor (comparable to a "fluid cloud").

[0143] In a preferred embodiment, the plate elements are sealed against each other with a sealing element to be pressure-tight up to a pressure of 1 bar.

[0144] A fourth aspect of the invention relates to a reactor for the production of synthesis gas, wherein the reactor comprises a plurality of reactor modules according to the invention, the reactor modules comprising a system with heating elements located in the recesses.

[0145] According to a preferred embodiment, the total number of heating elements in the reactor is a multiple of 3. This is advantageous with regard to the electrical connection, which is preferably a delta connection.

[0146] As described above, it is preferred that the heating elements protrude laterally from both sides of the plate element. According to this embodiment, it is further preferred that the reactor also includes a [missing element] that completely or partially [missing element]. The heating elements are enclosed by insulation, and they also protrude from the insulation, being equipped with electrically conductive leads at their two opposite ends outside the insulation. The advantage is that the electrically conductive leads (also called electrical connections) are effectively shielded from the heat emanating from the reactor by the insulation, thus effectively preventing coke formation on and around the electrical connections. This prevents short circuits.

[0147] It is preferred that a catalyst is arranged in the reaction plate element reaction zone.

[0148] According to a preferred embodiment, the reaction plate element reaction zone is arranged opposite at least one recess of the plate element according to the invention. As already described above, this leads to effective heat transfer into the reaction plate element reaction zone. As described above, the shortest distance between the recess closest to the reaction plate element reaction zone and the reaction plate element reaction zone is preferably at most 4 mm.

[0149] A fifth aspect of the invention relates to a method for carrying out a chemical reaction. The method is characterized in that it is carried out in a reactor according to the invention and that a fluid flowing through one or more fluid channels is heated by heat conduction through the at least six heating elements.

[0150] According to a preferred embodiment, the fluid flowing through the one or more fluid channels does not come into physical contact with the at least six heating elements. Here, too, only the intended fluid path is relevant.

[0151] Preferably, all heating elements or subgroups of heating elements are heated up or cooled down to different temperatures over time, either between the subgroups or between all heating elements. The heating elements or subgroups of heating elements are therefore controlled separately from one another.

[0152] Preferably, all heating elements or subgroups of heating elements are heated or cooled spatially within the plate element to temperatures that differ between the subgroups or between all heating elements within the same period of time.

[0153] According to a preferred embodiment, the chemical reaction is an endothermic or only weakly exothermic chemical reaction.

[0154] A weakly exothermic reaction within the scope of the present invention is a chemical reaction in which a relatively small amount of energy is released in the form of heat. is released. With regard to the enthalpy change (AH), a weakly exothermic reaction within the scope of the present invention exhibits an enthalpy change of more than -40 kJ / mol to approximately -60 kJ / mol.

[0155] According to a preferred embodiment, the process is a method for producing synthesis gas, and the chemical reaction is a reverse water-gas shift (rWGS) reaction. The rWGS reaction preferably takes place in the reaction plate element reaction zone.

[0156] According to another preferred embodiment, the process is an ammonia synthesis.

[0157] According to a further preferred embodiment, the plate elements according to the invention each have a reaction zone in which a hydrogenation catalyst is arranged, and in which a hydrogenation reaction takes place. The advantages of a hydrogenation reaction have already been described above.

[0158] According to a preferred embodiment, the heating elements protrude laterally from openings on both sides of the plate element, wherein the reactor further comprises insulation that completely or partially encloses the reactor, and the heating elements also protrude from the insulation and have electrically conductive leads at both ends outside the insulation, wherein the method is carried out such that the temperature at the electrical leads is less than 400 °C, preferably less than 300 °C. The advantages of this embodiment have also already been described above.

[0159] According to a further preferred embodiment, heat is transferred from a heating element to a fluid flowing through one or more fluid channels by means of heat conduction with a heat transfer coefficient of more than 250 W / (m²). 2 K) and / or a heat flow of more than 550 W. As described above, this is difficult to achieve with a direct-acting heating element.

[0160] In a preferred embodiment, the mass loss through the sealing elements during operation of the reactor is less than 10%, preferably less than 5 wt.%.

[0161] The present invention is also described with reference to the following numbered items, which can be combined with each other and / or with embodiments of the description: 1. Plate element for the construction of a plate reactor, wherein the plate element has a maximum length “I” and a maximum width “b” and a maximum height “h”, wherein the following applies: I > 3 b, preferably I > 5 b, and wherein the plate element has six or more recesses, each for receiving a heating element, wherein the plate element further has at least one inlet opening for a fluid and one or more fluid channels, and wherein the six or more recesses are not in material contact with the one or more fluid channels, nor with the at least one inlet opening, nor with any other fluid-conducting structures that may be present in the plate element, in particular with reaction zones optionally provided in the plate element. 2. Plate element according to Item 1, wherein the six or more recesses are located inside the plate element. 3. Plate element according to Item 1 or 2, wherein the plate element is composed of two separably connected, preferably screwed, half-plate elements which together form the plate element. 4. Plate element according to one of the preceding items, wherein the plate element can be separated into two half-plate elements by dividing the plate element at a mid-plane. 5. Plate element according to item 3 or 4, wherein the six or more recesses are defined by the two half-plate elements. 6. Plate element according to one of items 3-5, wherein the two half-plate elements are counterparts and each has half-plate element recesses arranged opposite each other in the plate element and together form the six or more recesses. 7. Plate element according to Item 6, wherein the half-plate element recesses are semi-cylindrical and the six or more recesses in the plate element are cylindrical. 8. Plate element according to one of items 3-7, wherein at least one of the half-plate elements is characterized in that half-plate element recesses are arranged on one side and fluid channels are arranged on the opposite side, preferably this applies to both half-plate elements. 9. Plate element according to one of the preceding items, wherein the plate element has two opposing side surfaces, the longest dimension of which corresponds to the width “b” of the plate element, wherein the recesses are arranged in a continuous area of ​​the plate element which comprises a maximum of 30% of the length of the plate element as well as one of the side surfaces. 10. Plate element according to one of the preceding items, wherein each recess has one or two openings, preferably two. 11. Plate element according to one of items 3-10, wherein each recess has one or two openings designed in such a way that a heating element can be inserted through the opening(s) into the respective recesses. 12. Plate element according to one of the preceding items, wherein at least one recess extends through the entire width of the plate element, and wherein this at least one recess has two openings arranged opposite each other, preferably where this applies to all recesses. 13. Plate element according to one of the preceding items, wherein the plate element has 4 to 18 recesses, preferably e to 18, more preferably 6 to 15, and still more preferably 9 to 12. 14. Plate element according to one of the preceding items, wherein the recesses are cylindrical and each has a longitudinal axis. 15. Plate element according to one of items 5 to 13, wherein the longitudinal axes of the cylindrical recesses are arranged substantially parallel to each other. 16. Plate element according to one of items 14-15, wherein the longitudinal axes of the cylindrical recesses are arranged substantially parallel to the width of the plate element. 17. Plate element according to one of the preceding items, wherein the plate element further comprises a reaction zone for receiving a catalyst. 18. Plate element according to Item 17, wherein the reaction zone is located outside an area of ​​the plate element which comprises a maximum of 30% of the length of the plate element and one of the side faces. 19. Plate element according to Item 17, wherein the shortest distance between the recess closest to the reaction zone and the reaction zone is at least 5 mm, preferably at least 6 mm, more preferably at least 7 mm, and even more preferably at least 8 mm. 20. Plate element according to one of the preceding items, characterized in that it is configured to operate at temperatures above 600°C, preferably above 700°C. 21. System comprising the plate element according to one of items 1-20 and six or more heating elements, preferably 6 to 18 heating elements, more preferably 6 to 15, and even more preferably 9 to 12, each of which is arranged in recesses of the plate element. 22. System according to Item 21, wherein the heating elements are either separately or as subgroups of the total number of heating elements, and their temperature can be controlled and regulated. 23. System according to Item 21 or 22, wherein heating elements are heating cartridges. 24. System according to one of items 21 to 23, wherein heating elements protrude laterally from the plate element on at least one side, preferably from both sides, preferably by at least 10% of the total length, more preferably by at least 20% of the total length of the heating element. 25. System according to one of items 21 to 24, wherein heating elements each have electrically conductive leads at their two opposite ends outside the plate element. 26. System according to one of items 21 to 25, further comprising a control unit for setting different temperatures in two or more different subgroups of heating elements in the length of the plate element. 27. System according to one of items 21 to 26, wherein the system is designed such that heat is transferred from a heating element into a fluid channel through one or more fluid channels. Flowing fluid over a solid material of the plate element with a heat transfer coefficient of more than 250 W / (m²) 2 K) and / or a heat flow of more than 550 W. 28. System according to one of items 21 to 27, wherein the plate element further comprises a reaction zone in which a catalyst is arranged. 29. Reactor module for the production of synthesis gas, comprising: a plate element according to one of items 1 to 20 or a system according to one of items 21 to 28, a reaction plate element comprising a reaction plate element reaction zone for receiving a catalyst, wherein the reaction plate element is different from the plate element. 30. Reactor module according to Item 29, wherein the plate element is separable and thermally conductively connected to the reaction plate element. 31. Reactor module according to item 29 or 30, wherein the recesses of the plate element and the reaction plate element reaction zone are arranged opposite and overlapping. 32. Reactor module according to one of items 29 to 31, wherein the shortest distance between the recess closest to the reaction plate element reaction zone and the reaction plate element reaction zone is at most 4 mm. 33. Reactor for the production of synthesis gas, wherein the reactor comprises a plurality of reactor modules according to one of items 29-32, wherein the reactor modules comprise a system according to one of items 21 to 28. Reactor according to Item 33, wherein the total number of heating elements in the reactor is a multiple of 3. Reactor according to Item 33 or 34, wherein the heating elements protrude laterally from openings on both sides of the plate element, wherein the reactor further comprises insulation that completely or partially encloses the reactor, and the heating elements also protrude from the insulation and are equipped with electrically conductive leads at their two opposite ends outside the insulation. Reactor according to one of Items 33-35, wherein a catalyst is arranged in the reaction plate element reaction zone. Reactor according to one of Items 33-36, wherein the reaction plate element reaction zone is arranged opposite at least one recess of the plate element.A method for carrying out a chemical reaction, characterized in that the method is carried out in a reactor according to one of items 33 to 37 and that a fluid flowing through one or more fluid channels is heated by heat conduction through the at least six heating elements. A method according to item 38, wherein the fluid flowing through one or more fluid channels does not come into physical contact with the at least six heating elements. A method according to item 38 or 39, characterized in that all heating elements or subgroups of heating elements are heated up or cooled down over time to temperatures that differ between the subgroups or between all heating elements. A process according to one of items 38 to 40, characterized in that all heating elements or subgroups of heating elements are heated or cooled spatially within the plate element to temperatures that differ between the subgroups or between all heating elements within the same period of time. A process according to one of items 38 to 41, wherein the chemical reaction is an endothermic or only weakly exothermic chemical reaction. A process according to one of items 38 to 42, wherein the process is a process for producing synthesis gas and the chemical reaction is a reverse water-gas shift (rWGS) reaction. A process according to item 43, wherein the rWGS reaction takes place in the reaction zone of the reaction plate element. A process according to one of items 38-42, wherein the process is an ammonia synthesis.A method according to any one of items 38-45, wherein the plate elements each have a reaction zone in which a hydrogenation catalyst is arranged, and a hydrogenation reaction takes place in the reaction zone. A method according to any one of items 38-46, wherein the heating elements protrude laterally from openings on both sides of the plate element, wherein the reactor further comprises insulation that completely or partially encloses the reactor, and the heating elements also protrude from the insulation and have electrically conductive leads at both ends outside the insulation, wherein the method is carried out such that the temperature at the electrical leads is less than 400 °C, preferably less than 300 °C. A method according to any one of items 38-47, wherein heat is transferred from a heating element to a fluid flowing through one or more fluid channels by means of thermal conduction. with a heat transfer coefficient of more than 250 W / (m²) 2 K) and / or a heat flow of more than 550 W. EXAMPLES

[0162] The present invention will now be explained in more detail using the following examples. Example 1 - Plate element according to the invention

[0163] An embodiment of the plate element according to the invention is shown in Figures 1A and 1B. Figures 1A and 1B show the same plate element; for better readability, only the maximum length “I”, maximum width “b” and maximum height “h” have been separately marked in Figure 1B.

[0164] The plate element 1 is cuboid in shape and comprises two separably connected half-plate elements 5a, 5b. The plate element 1 can be separated into the two half-plate elements 5a, 5b by dividing it in its central plane. The two half-plate elements 5a, 5b are screwed together. The two half-plate elements 5a, 5b are counterparts and each has semi-cylindrical half-plate element recesses (11a-11i; shown in Figure 2), which together form a total of nine internal cylindrical recesses 10a-10i. The cylindrical recesses 10a-10i have openings on the sides of the plate element 1. The plate element 1 has a maximum length "I", a maximum width "b", and a maximum height "h". The maximum height of a half-plate element is marked as “H” (see Fig. 1 B and 1C). The plate element 1 also has an inlet opening 20.Furthermore, the plate element 1 has a reaction zone 50 and two sets of fluid channels 40. The first set of fluid channels 40 connects the inlet opening 20 to the reaction zone 50; the second set of fluid channels 40 is located downstream of the reaction zone 50. Part of the second set of fluid channels is located opposite the recesses 10a-1 Oi.

[0165] The half-plate element 5a is shown in Figure 2 from two perspectives (front and back). Figure 3 shows a magnification of the semi-cylindrical half-plate element recesses 11a-11i in the half-plate element 5a. The half-plate element 5a has nine semi-cylindrical half-plate element recesses 11a-11i in the lower 30%. The half-plate element recesses are arranged on one side of the half-plate element 5a, and the fluid channels are located on the opposite side. The side of the half-plate element 5a is arranged. The half-plate element 5a also has a reaction zone that is adjacent to the recesses (more precisely: to the outer recess that is closest to the reaction zone). Example 2 - Reactor according to the invention

[0166] Figure 5 shows a section of a reactor 100 according to the invention, comprising a plurality of plate elements 1 of Example 1 according to the invention, including heating elements 110 arranged in the recesses. The plate elements 1 according to the invention are located directly adjacent to reaction plate elements 120. The heating elements 110 arranged in the recesses project laterally from both sides of the plate elements 1 and are equipped with electrically conductive leads 130 at their two opposite ends outside the reactor 100. Figure 6 shows an enlargement of area A of Figure 5. Example 3 - Analysis of the influencing factors on temperature T and coupling of heating power P

[0167] For an arrangement with 9 heating cartridges along the heating length, the influencing factors on the temperature T and the possible coupling of heating power P were determined. The heating power refers to a reactor with 9 of the plate elements according to the invention and a width of b = 25 cm. The spacing between the heating elements (here: heating cartridges) was regular, and the area heated by one heating cartridge corresponded to a length L1 of 30 mm (distance from the midpoint between the heating cartridge in question and the upstream heating cartridge to the midpoint between the heating cartridge in question and the downstream heating cartridge). The cartridges have a diameter of 12.5 mm, and the plate element has a total height h of 20 mm (two half-plate elements with a height H of 10 mm each). Furthermore, the 9 cartridges are heated by two or three heating circuits.In the standard configuration, the first three heating cartridges operate at 870°C, while the last six heating cartridges operate at 910°C. Deviations from this are specified in the relevant example(s) and illustrate the system's efficiency under these conditions. The examples assume a gas outlet temperature of 610°C from the heat exchange zone (including or excluding the hydrogenation zone) into the heating zone. Example 3A

[0168] Figure 7 shows the influence of the height H of half-plate elements with a semi-cylindrical design of the recesses. In a one-piece plate with bores, the plate height values ​​must be doubled. The figure shows the significant decrease in performance when the plate element is designed with a total height h (h = 2 * H) of more than 30 mm. The achievable performance and final temperatures at the outlet and when fed into a RWGS reaction zone also decrease. Example 3B

[0169] Figure 8 shows the temperature profile in the heated gas before and between the heating cartridges. The temperature increase follows an almost linear relationship, as the separate temperature control of cartridges 4-9, with their inherently higher surface temperatures, leads to a further temperature increase. The corresponding power output per heating cartridge, Px, is shown in Figure 9. Increasing the control temperature from cartridge 4 onwards allows for an increase in the power input into the fluid from cartridge 4 onwards. A further increase in the outlet temperature would be possible with a third, individual heating circuit starting at cartridge 7.

[0170] Figure 10 shows a detailed analysis of the temperature rise at the first heating cartridge. It can be seen that the temperature rise is steepest near the heating cartridge at x = 0 mm, as this is where there is the least resistance to heat conduction. In gas applications, heat transfer to the gas is generally very strongly heat flow imitating the heat flow, which is why the heated length of a cartridge (L1) is preferably no more than approximately three times the heating cartridge diameter. For larger values ​​of x, the temperature rise curve flattens out due to the increasing influence of the reduced heat conduction in the reactor material. In the example shown with a 12.5 mm heating cartridge diameter, this flattening begins at L1 = 30 mm. Therefore, L1 is preferably located between 2D and 3D, and the distance between two heating cartridges is preferably between 1D and 2D, in order to minimize the number of cartridges while maximizing the heat flow.

Claims

REQUIREMENTS 1. Plate element for the construction of a plate reactor, wherein the plate element has a maximum length “I” and a maximum width “b” and a maximum height “h”, wherein the following applies: I > 3 b, preferably I > 5 b, and wherein the plate element has six or more recesses, each for receiving a heating element, wherein the plate element further has at least one inlet opening for a fluid and one or more fluid channels, and wherein the six or more recesses are not in material contact with the one or more fluid channels, nor with the at least one inlet opening, nor with any other fluid-conducting structures that may be present in the plate element, in particular with reaction zones optionally provided in the plate element.

2. Plate element according to claim 1, wherein the plate element is composed of two separably connected, preferably screwed, half-plate elements which together form the plate element.

3. Plate element according to one of the preceding claims, wherein the recesses are cylindrical and each has a longitudinal axis.

4. Plate element according to one of the preceding claims, wherein the plate element has two opposing side surfaces, the longest dimension of which corresponds to the width “b” of the plate element, wherein the recesses are arranged in a continuous area of ​​the plate element which comprises a maximum of 30% of the length of the plate element and one of the side surfaces.

5. System comprising the plate element according to one of claims 1-4 and six or more heating elements, preferably 6 to 18 heating elements, more preferably e to 15, more preferably 9 to 12, each of which is arranged in recesses of the plate element.

6. System according to claim 5, wherein heating elements project laterally from the plate element on at least one side, preferably from both sides, preferably by at least 10% of the total length, more preferably by at least 20% of the total length of the heating element.

7. System according to one of claims 5-6, wherein the system is configured such that heat is transferred from a heating element into a fluid flowing through one or more fluid channels via a solid material of the plate element with a heat transfer coefficient of more than 250 W / (m²). 2 K) and / or a heat flow of more than 550 W.

8. Reactor module for the production of synthesis gas, comprising: a plate element according to one of claims 1-4 or a system according to one of claims 5-7, a reaction plate element comprising a reaction plate element reaction zone for receiving a catalyst, wherein the reaction plate element is different from the plate element.

9. Reactor module according to claim 8, wherein the recesses of the plate element and the reaction plate element reaction zone are arranged opposite and overlapping.

10. Reactor for the production of synthesis gas, wherein the reactor comprises a plurality of reactor modules according to any one of claims 8-9, wherein the reactor modules comprise a system according to any one of claims 5-7.

11. Reactor according to claim 10, wherein the heating elements protrude laterally from openings on both sides of the plate element, wherein the reactor further comprises insulation completely or partially enclosing the reactor and the heating elements also protrude from the insulation and are equipped with electrically conductive leads at their two opposite ends outside the insulation.

12. Method for carrying out a chemical reaction, characterized in that the method is carried out in a reactor according to one of claims 10-11 and that a fluid flowing through one or more fluid channels is heated by means of heat conduction through the at least six heating elements.

13. Method according to claim 12, characterized in that all heating elements or subgroups of the heating elements are heated up or cooled down over time to temperatures that differ between the subgroups or between all heating elements.

14. Method according to one of claims 12-13, characterized in that all heating elements or subgroups of the heating elements are heated or cooled spatially in the plate element to temperatures different between the subgroups or between all heating elements within the same period of time.

15. A method according to any one of claims 12-14, wherein the method is a method for producing synthesis gas and the chemical reaction is a reverse water-gas shift (rWGS) reaction.

16. Method according to one of claims 12-15, wherein the heating elements protrude laterally from openings on both sides of the plate element, wherein the reactor further comprises insulation completely or partially enclosing the reactor and the heating elements also protrude from the insulation and have electrically conductive leads at both ends outside the insulation, wherein the method is carried out such that the temperature at the electrical leads is less than 400 °C, preferably less than 300 °C.

17. Method according to one of claims 12-16, wherein heat is transferred from a heating element to a fluid flowing through one or more fluid channels by means of heat conduction with a heat transfer coefficient of more than 250 W / (m²). 2 K) and / or a heat flow of more than 550 W.

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