Multilayer reactor with multiple structural layers

Description

[0001] The present invention relates to a reactor with a multilayer structure, wherein the various layers are structured in a special way to enable improved heat transfer during catalytic reactions. Furthermore, the present invention relates to multireactor structures, methods for producing the reactors and multireactor structures, as well as their use and applications. State of the art:

[0002] In (micro-)structured reactors, solid catalysts can be introduced as layers or as particle fillings. Such reactors are typically used for fast and high-energy reactions to ensure efficient heat inflow or outflow by means of a layered structure, i.e., alternating levels with flow of reaction medium and heat transfer medium, and thus to operate the reaction as close to the set temperature as possible. When such a reactor is filled with particles, the small dimensions of the structures in one level result in a structure-to-particle size ratio of less than 10. This is to keep the pressure loss during the flow of reaction medium to a minimum and to prevent the adhesive forces between individual particles from becoming greater than the weight of the individual particles, thus avoiding agglomeration.Agglomeration is unfavorable and hinders the filling of the structures with catalyst. Since the flat wall surface and particle contact near the wall result in higher bed porosity, a small structure-to-particle size ratio significantly influences the reduced porosity near the wall and thus results in uneven reactant velocities. One approach to improving uniform flow is milled or etched structures with offset columns, as in WO 2017 / 013003. The costly structure fabrication and the fact that mixing at the columns is only a two-dimensional approach represent limitations.

[0003] Reactors described in the prior art typically have one or more catalysts for carrying out at least one exothermic reaction. As the catalytic activity decreases, this catalyst must be renewed at regular intervals known to those skilled in the art by removing it from the reactor and refilling it. To achieve this, the reactor must allow for uniform loading and unloading of catalyst. To dissipate the exothermic energy by thermal conduction, a material connection to the cooling passage is also required. These connections must not exceed a maximum distance. This presents various challenges. For example, due to their design, the individual layers are essentially only suitable for use in diffusion-welded microstructured reactors.There must be as many continuous connections as possible, one above the other, perpendicular to the flow direction, so that heat transport through several levels of plates to the next cooling level is maximized.

[0004] In state-of-the-art reactors, it is often a problem that the flow cannot be distributed sufficiently evenly in the cavities in the reactor and unequal porosities of the bed as well as the porosity differences near the walls are not sufficiently compensated so that the residence time of the reactants is the same in all catalyst zones.

[0005] Likewise, the catalyst should be able to be filled and removed evenly from the reactor chamber; this is not or only slightly fulfilled in some designs according to the state of the art.

[0006] Furthermore, on the one hand, the highest possible proportion of catalyst volume should be able to be introduced into the reactor, while on the other hand, heat exchange and heat transport should be as high as possible so that conditions in the reactor are as isothermal as possible. This problem, too, is often not adequately addressed in state-of-the-art reactors.

[0007] From WO 90 / 13784 A1, for example, various heat exchanger structures are known, but no reactors and no indication of the considerably more difficult flow conditions and resulting challenges caused by catalyst filling.

[0008] From EP 1 995 545 A2, for example, a design comprising rectangular channels is known, the application of which, however, can lead to preferential flows developing within the catalyst bed, caused by uneven pressure losses across the flow cross-section in the main flow direction, so that uneven pressure and thus flow conditions develop and, as a result, uneven temperature distribution in the reactor and, ultimately, lower selectivity can occur.

[0009] WO 2006 / 102675 A1 describes structures with a main channel in which different layers are superimposed by at least 50%. These structures require Reynolds numbers greater than 100 and are to be coated with a catalyst.

[0010] Further prior art that could be mentioned are EP 2 543 434 A1, US 6,968,892 B1 and DE 10 2011 079 634 A1 as well as EP 1 224 967 A2, US 2010 / 174124 A1, US 7,935,734 B2.

[0011] In this respect, based on the known state of the art, there is still a considerable need to improve the current state of the art. Task:

[0012] The object of the present invention was therefore to overcome the disadvantages of the prior art described above and to provide reactors which no longer have these problems or at least only to a considerably lesser extent.

[0013] A reactor design should be found that allows more flexibility in manufacturing and is not limited to diffusion bonding, but also allows other manufacturing methods.

[0014] Furthermore, a design should be found in which the flow can be distributed evenly in the cavities in the reactor to an extent that is improved compared to the state of the art and in which uneven porosities of the bed as well as the porosity differences near the wall are compensated.

[0015] The reactors should also be easy to fill with catalyst and the catalyst should then be easy to replace.

[0016] In addition, reactors should be found in which, on the one hand, the highest possible proportion of catalyst volume can be introduced, but on the other hand, the heat exchange and heat transport are as large as possible, so that the conditions in the reactor are as isothermal as possible.

[0017] Furthermore, reactor structures coated with catalyst or catalytically active material should be avoided in order to facilitate simpler production on the one hand and to enable filling and refilling, if necessary with other catalysts, on the other hand.

[0018] Further tasks will become apparent to the person skilled in the art when considering the claims and the following description. Solution:

[0019] These and other objects which will become apparent to the person skilled in the art from the present description are achieved by the subject matter presented in the claims, the dependent claims representing preferred and particularly advantageous embodiments.

[0020] In the context of the present invention, all quantities are to be understood as weights unless otherwise stated.

[0021] For the purposes of this invention, the term "ambient temperature" refers to a temperature of 20°C. Unless otherwise stated, temperatures are in degrees Celsius (°C).

[0022] Unless otherwise stated, the reactions or process steps listed are carried out at ambient pressure (=normal pressure / atmospheric pressure), ie at 1013 mbar.

[0023] Pressure specifications within the scope of the present invention, unless otherwise stated, mean absolute pressure specifications, ie x bar means x bar absolute (bar a ) and not x bar gauge.

[0024] In the context of the present invention, the reactor front is understood to be the side from which the reaction medium / fluid flows into the reactor. In the context of the present invention, the term "side wall" in connection with diffusion-bonded multilayer reactors refers to the area on the left and right sides of the multilayer reactor (as opposed to the reactor front and the opposite rear side) that connects the top and bottom sides and seals them off from the outside. In the context of the present invention, the "points" at which the various (structural) layers are connected to one another are understood to be real points (i.e., small areas) and not mathematical points, i.e., what is usually understood as connection points in mechanics or in mechanical devices.

[0025] In the context of the present invention, the term "temperature lift" is understood to mean the maximum temperature difference compared to the actually desired reaction temperature (in particular in the sense of an excess temperature that occurs compared to the target temperature).

[0026] The present invention particularly relates to a reactor with a preferably welded multi-layer structure, which has an upper fluid-tight cover layer, a lower fluid-tight cover layer, fluid-tight side walls and, in between, at least one reaction space which is defined by a plurality of superimposed structural layers parallel to the cover layers.

[0027] The individual structural layers each have a structure of parallelograms arranged periodically in several rows, each edge-to-edge, wherein the parallelograms are preferably rectangles, particularly preferably rhombuses, in particular squares, and wherein the surfaces of the parallelograms are designed as recesses and the edges as webs.

[0028] Each of the structural layers is offset relative to the one above or below it by a factor of 0.5±0.2 and 0.5±0.2 in the x- and y-direction, preferably +0.1 in each case, particularly preferably +0.05 in each case; the largest edge length of the rhombuses is normalized as 1 and thus specifies the x-direction, while the y-direction is orthogonal to this in the plane of the structural layer.

[0029] The side edges of the parallelogram structures in the structural layers are arranged rotated by 30 to 60°, preferably 45 to 55°, particularly preferably 40 to 50°, in particular 45°, in relation to the front and rear sides of the reactor, resulting in incomplete parallelogram structures with recesses that are not completely surrounded by webs at the front and rear sides of the reactor.

[0030] At the side edges of the reactor, the parallelograms, which are not complete due to their geometry, can either be partially open recesses or closed ones (this is also the case, for example, with the Figures 1 to 4 illustrated).

[0031] In the reactor of the present invention, the reaction chamber is flowed onto from the front of the reactor in a planar manner, with the incoming fluid flowing into the recesses that are not completely surrounded by webs.

[0032] The cover and structural layers consist of a material with good thermal conductivity, preferably a material with a thermal conductivity of 10 to 400 W / (mK). The material is preferably a weldable material, particularly preferably selected from the group consisting of nickel-based alloy(s), aluminum (thermal conductivity of approximately 300 W / (mK)), aluminum alloy(s), copper (thermal conductivity of approximately 400 W / (mK)), stainless steel, high-temperature alloys such as, in particular, 1.4876 or 2.6433, or mixtures thereof, in particular stainless steel. In one variant of the present invention, materials are selected that have a thermal conductivity of 12 to 25 W / (mK).

[0033] The contact points and surfaces of the webs of the superimposed structural layers are fully connected, particularly welded. These connections are fluid-tight.

[0034] A catalyst bed can be arranged in the recesses between the webs of the structural layers; in preferred variants, a catalyst bed is arranged in the recesses between the webs of the structural layers. The catalyst bed can be immobilized or retained in various ways, for example, by retaining devices or by bonding.

[0035] The coverage of the recesses of one layer by the webs of the layer above is 30-60%, preferably 30 to 55%.

[0036] In preferred embodiments of the present invention, the reactor has certain dimensions.

[0037] In these embodiments, the structural layers each have a thickness of 0.3 mm to 2 mm, preferably 0.5 mm to 1 mm, the webs have a width of 0.5 mm to 4 mm, preferably 1 mm to 3 mm, and the largest side length of the recesses is between 2 mm and 20 mm, preferably between 4 mm and 12 mm.

[0038] The cover layers have thicknesses within the same range as the structural layers, i.e., from 0.3 mm to 2 mm, preferably 0.5 mm to 1 mm; however, the thicknesses used are independent of those of the structural layers. In some embodiments, the cover and structural layers are made from the same raw material (e.g., sheet metal or metal foil) and thus have the same thickness. In other embodiments, the thicknesses of the cover layers differ from those of the structural layers depending on the desired heat dissipation, or for additional mechanical stabilization (then thicker than the structural layers).

[0039] It is also important that the recesses are at least a factor of 2, preferably at least a factor of 3, wider than the web width. Below a factor of 2, the space through which a catalyst bed can be filled and the reaction medium can flow gradually becomes too small; with a factor of 1, i.e., when the webs are as wide as the recesses, there is no space left for flow. On the other hand, the factor should not be too large, so that sufficient heat dissipation of the reaction heat via the webs is still possible. In special designs, this upper limit of the factor is a maximum of 6, preferably a maximum of 5. In particular, the factor is between 3 and 6.

[0040] In a rhombus or a square as a special case of a parallelogram, the largest edge length is naturally equal to the other edge length.

[0041] In this and all other dimensional specifications for the present invention, it will be understood by those skilled in the art that manufacturing-related tolerances are included; these can, as those skilled in the art are aware, differ depending on the manufacturing technology (for example, a punching process generally has different tolerances than a laser cutting process, an additive manufacturing process, or a waterjet process).

[0042] In some embodiments of the present invention, these structural dimensions may differ from one another in successive layers. In this case, however, it is essential that sufficient space remains for filling or flow, as described in the previous paragraph. For production-related reasons and to achieve the most uniform results possible, structural layers with the same structural dimensions are generally stacked on top of one another.

[0043] In further preferred embodiments of the present invention, the reactor has a ratio of web width to the longest side length of the recesses between 0.15 and 0.55, preferably between 0.25 and 0.45, averaged for all structural layers or, preferably, always the same for each individual structural layer. If the ratio is too low, the limit for technically reasonable weldability of the layers is not met. On the other hand, if the ratio is too high, the sensible limit for catalyst bed is exceeded. This is because if there is too much catalyst in relation to the amount of catalyst, heat dissipation via the webs of the individual structural layers may no longer be possible to a sufficient extent. In this context, however, it should be noted that for additive manufacturing processes, in particular 3D printing, the lower limit may be shifted. Nevertheless, the above-mentioned limits are preferred in this case too.

[0044] In further preferred embodiments of the present invention, the reactor has a void volume fraction of 45 vol.% to 75 vol.%, preferably 50 vol.% to 70 vol.%, particularly preferably 60 vol.% to 70 vol.%. Although the reactor of the present invention is not limited to operation with a catalyst bed, it is particularly well suited and primarily designed for such operation. The reactor has proven particularly well suited in these ranges.

[0045] In this respect, the empty volume for operation is filled with a bed of fine catalyst particles, which are preferably spherical. This is therefore a particularly preferred embodiment of the present invention.

[0046] In this context, it should be noted that the aspect of utilizing the cavity for filling with catalyst is a key feature of the present invention. It is important to be able to integrate a certain amount of catalyst per volume while simultaneously dissipating heat efficiently.

[0047] In further preferred embodiments of the present invention, a recess dimension of 6 mm and a web width of 1.5 mm are designed for square recesses. This results in an empty volume fraction of 64%. Adhering to certain limits for the web widths is particularly advantageous so that the relationship between released heat and heat dissipation capacity of the structure does not change drastically. The reactor according to the invention can be used, for example, for methanol synthesis, FT synthesis, or methanation, i.e., reactions that, under intensified microstructuring conditions, can have a volumetric energy release of at least 3 kW / L (minimum 2 kW / L) in the reaction volume. This energy must therefore be dissipated via the webs and the nodes. This is possible with the web dimensions preferred according to the invention.The energy released into the total volume (i.e., the volume occupied including the webs) should preferably be greater than 1 kW / L for a high degree of process intensification; therefore, a void space fraction of at least 50% is preferred in some designs. A void space fraction greater than 70% is also not practical, as heat dissipation via the nodes (contact points) is then not guaranteed.

[0048] The size of the individual reactors can be varied within wide limits. Preferred embodiments of the present invention comprise reactor sizes with lengths (flow direction) between 5 cm and 200 cm, preferably between 20 cm and 50 cm. At lengths exceeding this, the flowability of the particle aggregate within the reactor decreases increasingly and ultimately no longer reaches practical values. The width of the reactors according to the invention is, in preferred embodiments, between 5 cm and 150 cm, preferably between 30 cm and 80 cm. The height of the reactors according to the invention results from adding the thicknesses of the structural layers and the cover layers, as well as any intermediate layers present, and is, in preferred embodiments, between 3 mm and 2 cm. Embodiments can have heights of, for example, 5.2 mm or 5.4 mm or 8.4 mm or 9.8 mm.

[0049] The dimensions used in practice also depend on the cooling requirements and the heat exchanger elements used (and their effectiveness).

[0050] To ensure secure retention of the catalyst particles, some preferred embodiments of the present invention may provide a retention device for the catalyst particles at the front and rear of the reactor. This device may be a mesh-like component or a fine-pored metal or ceramic component, particularly a fine-mesh wire mesh. It is essential for the catalyst retention device used that it is made of a material that is not catalytically active in the chemical reaction taking place in the reactor and is inert toward the reactants and products. The mesh width or pore size of the catalyst retention device results from the size of the catalyst particles used and is selected such that they are retained and do not clog the meshes or pores. Such retention devices are known in principle to those skilled in the art.

[0051] In further preferred embodiments of the present invention, 2 to 10 structural layers are arranged between the cover layers in the reactor, and in particular for a maximum temperature difference of 15K, preferably a maximum temperature difference of 5K, between 2 and 7, preferably between 3 and 6, structural layers are arranged between the cover layers. This allows for particularly good performance profiles with regard to heat transfer (and dissipation).

[0052] It should be noted that the reactors of the present invention do not include rectangular channels and / or a main channel. The structures of the present invention do not allow for such channel structures. Furthermore, these geometries result in inferior results.

[0053] In further preferred embodiments of the present invention, the webs and / or walls are not coated with catalyst.

[0054] The front and back of the reactor are configured for the inflow and outflow of reaction medium.

[0055] In further preferred embodiments of the present invention, the structural layers on the front and rear sides of the reactor additionally have one or more edges with incorporated channels for distributing the reaction medium during inflow and outflow.

[0056] It is equally possible, and preferred in other embodiments of the present invention, that the structural layers on the front and rear sides of the reactor do not have such edges.

[0057] Irrespective of this, it is advantageous and therefore preferred in embodiments of the present invention if suitable distributor hoods or distributor chambers for the reaction medium are arranged on the front and rear sides of the reactor, thus ensuring a uniform supply and discharge of reaction medium into and out of the reactor. Such arrangements are well known to those skilled in the art.

[0058] In individual embodiments of the present invention, the outer cover layers of the reactors according to the invention can have ribs on their outer sides, which then protrude into the surrounding medium as a cooler structure.

[0059] The essential feature of the present invention, that the coverage of the recesses of one layer by the webs of the layer above is 30-60%, preferably 30 to 55%, naturally refers only to the structural layers.

[0060] In further preferred embodiments of the present invention, the webs are widened at the points where they are in contact with those of the structural layers below or above them. Circular widenings are preferred (due to symmetry). Preferably, one widening is arranged in the center of each web, in particular when the offset of the layers is 0.5 in the x and y directions, as defined above. The widening causes a maximum doubling, preferably a 40 to 60%, in particular 50%, widening of the web width. However, it is also possible to provide more than one widening per web and to deviate from the central positioning; if there are several widenings, it is preferable to arrange them evenly distributed over the respective web.

[0061] However, it is important not to allow the widenings to become too large so that catalyst filling and sufficient fluid flow are guaranteed.

[0062] In further preferred embodiments of the present invention, the reactor according to the present invention is manufactured by additive manufacturing methods, in particular 3D printing, or by stacking and subsequently welding the individual layers. In the case of welding the layers, this is preferably done by laser welding, electron beam welding, or diffusion welding. In some embodiments, diffusion welding is particularly preferred because it allows multiple layers, including the cover layers, to be easily welded together in a single step.

[0063] In further preferred embodiments of the present invention, the reactor according to the invention comprises, in addition to the cover layers and the structural layers, intermediate layers arranged between structural layers, with the proviso that at least two structural layers are arranged on each side of an intermediate layer before a further intermediate layer or a cover layer is arranged.

[0064] These intermediate layers are preferably unstructured layers which, apart from their arrangement within the reactor layer structure, correspond to the cover layers.

[0065] In principle, these configurations can be understood as a direct stacking of several reactors according to the invention, with the adjacent reactors sharing a cover layer. This can sometimes be advantageous from a manufacturing perspective, but it means that the resulting configuration cannot be disassembled flexibly, as is the case with configurations according to the invention in which several complete reactors according to the invention are stacked one above the other and do not share a cover layer.

[0066] The usable dimensions of the intermediate layers, in particular their thicknesses, correspond to the dimensions of the cover layers, but are selected independently of each other. This means that the length and width must be adapted to the corresponding dimensions of the structural and cover layers of the reactor; however, the thickness may differ from the thicknesses of the structural layers or those of the cover layers. It is also possible for the intermediate layers to be structured, with their structure differing from those of the structural layers. However, this is less preferred according to the invention and is not implemented in particular.

[0067] Examples of specific embodiments relating to multiple reactor arrangements according to the invention have the following sequences of the different components one above the other: DPD; DPPD; DPPPD; DPPPPD; DPZPD; DPZPZPD; DPZPZPZPD; DPZPZPZPZPD DPZPZPZPZPZPD.

[0068] Where D = cover layer, Z = intermediate layer, and P = a pair of structural layers. Of course, the intermediate layers do not have to be symmetrically surrounded by structural layers (this is simply easier to manufacture in some cases), but can also be distributed asymmetrically, as follows: DPZPPD; DPPZPPPD; DPPZPZPPPD:

[0069] These reactors are merely examples, and the present invention is by no means limited to them; many more layers can be arranged one above the other according to the invention.

[0070] The reactors according to the invention can be easily arranged to form multiple reactor arrangements by arranging them one above and / or next to each other, optionally but preferably with heat exchanger elements arranged in between.

[0071] Furthermore, the present invention relates to a multiple reactor arrangement comprising several reactors according to the present invention. In this arrangement, a plurality of reactors according to the invention are stacked, with heat exchanger elements arranged between each individual reactor.

[0072] These heat exchanger elements can take on different designs, depending on the reaction carried out in the reactors and the amount of heat to be removed or the amount of cold to be supplied.

[0073] In this respect, it is also possible for the heat exchanger elements to essentially form only one space, or for the surrounding space to function as the heat exchanger element, with the heat exchange medium being ambient air (or ambient atmosphere). However, it is preferred to use dedicated heat exchanger elements that supply or remove heat or cold by passing a heat exchanger medium.

[0074] In some embodiments, it is preferred to use heat exchanger elements based on structures as described in DE 10 2015 111 614 A1.

[0075] Within the scope of the multiple reactor arrangements according to the invention, it is possible in some embodiments to combine various reactors that differ in design from the reactors of the present invention with reactors according to the invention. In these embodiments, it is expedient if the various reactors have the same or at least approximately the same external dimensions. Accordingly, different or identical heat exchanger elements can also be used.

[0076] In most embodiments, however, it is preferable to combine only reactors according to the invention and only one type of heat exchanger element in the multiple reactor arrangements according to the invention; in particular, these all have the same external dimensions.

[0077] In the context of the present invention, the heat exchanger elements can be operated in cocurrent, crosscurrent or countercurrent to the flow direction of the reaction medium, depending on the exact type of heat exchanger elements used and the heat exchange requirement of the reaction carried out in the reactors.

[0078] The precise arrangement of the reactors in such multiple reactor arrangements according to the invention is also highly variable. It is possible to arrange many reactors according to the invention one above the other, side by side, or one behind the other.

[0079] Within the scope of the multiple reactor arrangements according to the invention, it is possible in some embodiments to form a checkerboard-like arrangement, wherein reactors, preferably reactors according to the invention, alternate with heat exchanger elements.

[0080] It is also possible to combine several such checkerboard-like arrangements, preferably in such a way that they are arranged offset from one another (by one "field" each).

[0081] The external dimensions of the multiple reactor arrangements according to the invention are, in principle, unlimited. Thus, within the scope of the present invention, it is entirely possible to construct multiple reactor arrangements that are several meters high and wide. Preferred embodiments of the present invention result in multiple reactor arrangements with a height of up to 2 meters, or up to 2.5 meters, or up to 3 meters.

[0082] Examples of specific embodiments relating to multiple reactor arrangements according to the invention have the following sequences of the different components one above the other: DPZPD-W-DPZPZPZPD-W-DPZPZPZPD-W-DPZPZPZPD-W-DPZPZPZPD-W-DPZPD; DPZPD-W-DPZPZPZPD-W-DPZPZPZPD-W-DPZPZPZPD-W-DPZPZPZPD-W-DPZPZPZPD-W-DPZPD; DPZPZPD-W-DPZPZPZPZPD-W-DPZPZPZPZPD-W-DPZPZPZPZPD-W-DPZPZPZPZPD-W-DPZPZPZPZPD-W-DPZPZPD.

[0083] Where D = cover layer, Z = intermediate layer, P = a few structural layers and W = heat exchanger element, in particular a pair of cooling foils according to DE 10 2015 111 614 A1 ( Figure 2 ).

[0084] These multiple reactor arrangements are merely exemplary and the present invention is in no way limited thereto.

[0085] These multiple reactor arrangements can be arranged side by side or combined with other arrangements.

[0086] The present invention further relates to a method for producing a reactor according to the invention by 3D printing or superimposing and then welding the individual layers, preferably by means of laser welding, electron beam welding or diffusion welding.

[0087] This method according to the invention is characterized in preferred embodiments of the present invention in that I) individual structural layers are manufactured, preferably by punching, laser cutting, water jet cutting or milling the structure out of a piece of material, a sheet of material or a material foil, IIa1) several structural layers are arranged offset from one another on top of one another and between an upper cover layer and a lower cover layer, and IIa2) the resulting multi-layer stack is connected to one another by means of diffusion welding via the respective contact points and contact surfaces, or IIb1) one structural layer is arranged over a previous cover layer or structural layer, then IIb2) the contact points and / or contact surfaces are connected to one another by means of laser welding, IIb3) steps IIb1) and IIb2) are repeated according to the desired number of structural layers, and IIb4) a final cover layer is applied and welded, whereby the individual layers are arranged in such a way thatthat the overlap of the recesses from one layer to the next is 30-60%, preferably 30 to 55%.

[0088] In further preferred embodiments of the present invention, the individual structural layers have a border surrounding the structure during production. In further preferred embodiments, this border can be removed after welding.

[0089] In other preferred embodiments, the rim is not removed and forms the reactor wall after welding.

[0090] In further preferred embodiments of the present invention, openings for the fluid supply and discharge lines are milled in the front and back of the structural layers following the other steps.

[0091] In further preferred embodiments of the present invention, the individual structural layers are adjusted to certain precisely defined external dimensions and then inserted precisely into an empty reactor housing.

[0092] This insertion can be done either individually for each structural layer, one after the other, or en bloc. The structural layers can either be welded together in advance to form a block and then inserted into the casing as a block, or they can be welded together with the cover layers after insertion into the casing.

[0093] The method according to the invention naturally also applies analogously in the case where intermediate layers are arranged.

[0094] However, the sequence of steps is then logically adapted accordingly and step IIb4) is replaced as follows: IIb4a) an intermediate layer is applied and welded, IIb4b) steps IIb1) and IIb2) are carried out according to the desired number of structural layers arranged after the intermediate layer, IIb4c) steps IIb4a) and IIb4b) are repeated as often as intermediate layers are to be arranged, and IIb4z) a final cover layer is applied and welded.

[0095] In further preferred embodiments of the present invention, the process comprises the arrangement of catalyst retention devices, preferably mesh-like components or fine-pored metal or ceramic components, in particular fine-mesh wire mesh, at the front and rear of the reactor. The catalyst retention device at the front of the reactor is attached either during reactor manufacture or after filling with catalyst.

[0096] It is possible within the scope of the present invention that the method comprises the step of filling the reaction space with catalyst filling before applying the final cover layer.

[0097] In other preferred embodiments of the present invention, the method comprises the step of filling the reaction chamber with catalyst filling from the front of the reactor after completion of the reactor (as step III). In this case, the filling process expediently comprises the steps of arranging the catalyst retaining device at the rear of the reactor (step IIIa), tilting the reactor onto its rear side (step IIIb) so that the front of the reactor then faces upwards, filling the reactor with catalyst bed through the front (step IIIc), optionally with shaking movements or the like, and arranging the catalyst retaining device at the front of the reactor (step IIId). Preferably, at least one of the catalyst retaining devices is arranged such that it can be removed non-destructively in order to facilitate the replacement or removal of the catalyst.

[0098] Furthermore, in further embodiments, the reactors according to the invention can be provided with distributor hoods or distributor spaces for the reaction medium at the front and rear sides within the scope of the process according to the invention (step IV).

[0099] Last but not least, the present invention relates to the use of the reactors according to the invention or the multiple reactor arrangements according to the invention or one of the reactors produced by the process according to the invention for exothermic or endothermic reactions.

[0100] The reactors according to the invention, multiple reactors or reactors produced by the process according to the invention are particularly suitable for exothermic reactions, such as methanol synthesis or methanation or Fischer-Tropsch syntheses, in particular Fischer-Tropsch syntheses.

[0101] In this respect, particularly preferred embodiments of the present invention relate to the use of the reactors according to the invention or the multiple reactor arrangements according to the invention or one of the reactors produced by the process according to the invention for methanol synthesis or methanation or Fischer-Tropsch syntheses, in particular Fischer-Tropsch syntheses.

[0102] The present invention therefore also relates in particular to welded multilayer structures for fluid redispersion and heat conduction in catalyst beds, as also described above and below.

[0103] The present invention is based on the fact that the developed structure, which is reminiscent of a net, is suitable for several joining methods and additive manufacturing processes.

[0104] The reactors according to the invention have (see also Figure 1) in apparatus construction, many continuous contact points that can be connected perpendicular to the flow direction through the plate stack, either by so-called diffusion welding or by blasting processes, such as preferably laser welding or electron beam welding.

[0105] The present invention is therefore also based on the fact that the flow through the reactor is distributed evenly by recurring structures which are arranged in a regularly overlapping manner and each recess in a structural layer (plate) connects four recesses below and above it (see also Figure 2This arrangement results in recurring mixing and flow interruption in both spatial directions perpendicular to the flow direction, which leads to a compensation of porosity differences in the catalyst bed as well as between near-wall particles and particle-particle composites. This, in turn, achieves a uniform residence time for individual flow paths through the reactor. This avoids the need for extensive effort to homogenize the local particle bulk density.

[0106] In the present invention, the individual recesses are large enough to easily accommodate particles, particularly catalyst particles / catalyst bed, with a diameter of 50-300 µm. At the same time, the arrangement allows the structure to be penetrated with ultrasound (when filled with liquids) throughout the entire reactor to free the reactor of particle residues. This significantly simplifies reactor cleaning. Among other things, it makes it possible to use the same reactor for a completely different reaction after cleaning and refilling with a different catalyst.

[0107] In the context of the present invention, the cavities are not completely filled with (liquid) catalyst, but are filled with catalyst bed, wherein the individual catalyst particles preferably have a particle size distribution of 50 µm to 500 µm, preferably 50 µm to 300 µm measured by laser diffraction.

[0108] An example of catalysts that can be used in preferred embodiments in reactors according to the invention for methanol syntheses are Cu / ZnO / Al 2 O 3 catalysts with a particle size distribution of 200 µm to 400 µm, measured by laser diffraction.

[0109] An example of catalysts that can be used in preferred embodiments in reactors according to the invention in Fischer-Tropsch syntheses are cobalt-based catalysts with a particle size distribution of 50 µm to 200 µm, measured by laser diffraction.

[0110] Furthermore, within the scope of the present invention, the intersecting connecting webs allow short heat conduction paths through orderly, regular connections to the cooling passage. In addition, the connection method (manufacturing method) ensures a material-to-material connection to the cooling passage, i.e. mixing of the reaction medium and the heat exchanger medium is excluded. Regardless of which connection method (manufacturing method) is ultimately used within the scope of the present invention, there is no contact resistance due to the material-to-material connection. Via the staggered arrangement of the recesses and the connection of one recess with four recesses in the level above (structural layer) and again with four recesses in the level below (structural layer), the preferably highly conductive construction material runs through the catalyst region. The distances to the contact points are arranged symmetrically and minimal in length.This results in short heat transport paths from the poorly thermally conductive catalyst mass to the thermally conductive construction material and also short transport paths within the construction material.

[0111] In some embodiments of the present invention, the heat transfer path and the ratio of heat transfer path to particle size can thus be easily adjusted by adjusting the thickness of the plates and the recess size. Both parameters depend essentially on the local heat release potential of the reaction and the particle size used.

[0112] An advantage of the present invention is that it is suitable for several welding processes taking into account catalyst integration and removal as well as isothermal conditions in the reactor.

[0113] Another advantage is that the geometry of the recesses is adjustable in size. Together with the selection of the respective structural layer thickness, the number of heat conduction bridges per volume and the width for filling with microparticles of different sizes can be variably adjusted. This also allows the volume-related energy release to be controlled, minimizing the number of cooling levels incorporated in the system, and maximizing the catalyst volume per reactor volume.

[0114] Particularly advantageous are the simplified filling and emptying with catalyst, the high heat dissipation with simultaneous maximum volume utilization with catalyst, a significantly improved residence time behavior (narrower residence time distribution -> plug flow behavior despite local porosity differences in the particle bed).

[0115] It is also advantageous from an economic and manufacturing point of view that simplified manufacturing processes and thus a significant reduction in costs and thus competitiveness of the reactor technology compared to the standard multi-tubular tube reactors are possible.

[0116] In some variants, the recesses in the structural layers of the present invention can be easily machined from material foils using cost-effective manufacturing processes such as punching, laser cutting, or waterjet cutting. Furthermore, the possibility of manufacturing using laser welding or similar methods is advantageous because it is easier to automate than, for example, diffusion welding, thus enabling a significant increase in the number of units produced per year. The same applies to the manufacture of the reactors according to the invention using additive manufacturing processes (3D printing), as this can be automated to a high degree. However, since manufacturing using diffusion welding is also still possible, the present invention is highly variable, which is a further advantage.

[0117] The person skilled in the art can, insofar as these are not explicitly described in this description, determine the exact design of the devices described, such as size, wall thicknesses, materials, etc., to suit the reaction conditions envisaged for a specific reaction within the scope of his general technical knowledge.

[0118] When describing the devices according to the invention, parts or the entire device are labeled as "consisting of," this refers to the essential components mentioned. This does not exclude self-evident or inherent parts such as lines, valves, screws, housings, measuring devices, storage containers for reactants / products, etc.

[0119] Unless explicitly described, the individual parts of the devices are operatively connected to one another in a customary and known manner.

[0120] The various embodiments of the present invention, for example - but not exclusively - those of the various dependent claims, can be combined with one another in any desired manner, provided that such combinations do not contradict one another. Character description:

[0121] The present invention is explained in more detail below with reference to the drawings. The drawings are not to be interpreted in a limiting sense and are not to scale. The drawings are schematic and, furthermore, do not contain all features found in conventional devices. Instead, they are reduced to the features essential to the present invention and its understanding. For example, screws, connections, etc., are not shown or are not shown in detail. The same reference numerals indicate the same features in the figures, the description, and the claims.

[0122] Figure 1shows a sectional view of a reactor 1 according to the invention. The cover layers are not shown for clarity. In this figure, four structural layers arranged one above the other are shown. 2 One can clearly see the structure consisting of bars 4 and recesses 3. The recesses 3 are square in the example of this figure. Furthermore, there is a border at the bottom right 5 In this illustration, the reactor is flowing with reaction fluid from the bottom left (= the front); this is indicated by the arrows in this figure. Also illustrated are two contact points 6, ie points at which all structural layers are in contact with each other or in other words points that are perpendicular to the flow direction through all structural layers 2(and cover layers) are connected through them (of course, there are more contact points per structural layer, but for the sake of clarity, only two are shown here). At these points, the layers are joined together, for example, by laser welding, electron beam welding, or diffusion welding; if the reactor is manufactured by 3D printing, a continuous build-up of the structure in the vertical direction takes place at this point during printing. Via the contact points 6 The heat (or cold) is then conducted to the cover layers (not shown), from which the heat (or cold) is then transferred to another medium, usually a heat exchange medium. In the recesses 3Catalyst particles can be arranged (not shown). This figure also clearly shows the offset of the individual structural layers from each other, which here amounts to 0.5 length units (one length unit equals the length of the side edge of a recess) in the x- and y-direction (x-direction equals the direction of a side edge of a recess and y-direction orthogonal in the plane of the structural layer 2 ). The current or flow direction A of The reaction fluid is, as mentioned, illustrated by the arrows. The fluid initially flows into the open recesses at the front, which in this example are triangular (half or quarter squares). When the fluid then encounters webs, it is directed upwards and / or downwards into recesses. 3 the structural layer above or below 2Due to the special structure, a very uniform flow through the entire reaction chamber (i.e. the sum of all recesses) is achieved, even at the edge 5 of the reactor 1. This is indicated by the arrows.

[0123] Figure 2 shows sections of a pair of slides 2 with slit-shaped offset slits in the edge 5, which, when placed on top of each other, form a continuous channel. The foils 2 are structures worked out of a material foil and thus represent - after they are arranged one above the other in the finished reactor - each a structural layer according to the invention 2.

[0124] Figure 3 shows sections of a pair of slides 2 with unstructured edge area 5. After arranging and merging the slides 2,For example, by means of laser welding or a diffusion welding process, the edge area 5, for example, by milling in the direction of flow. The films 2 are there, as in Figure 3 also, structures worked out of a material foil and thus represent - after they are arranged one above the other in the finished reactor - each a structural layer according to the invention 2.

[0125] The Figures 4 and 5 show for the Fischer-Tropsch synthesis ( Figure 4 ) or for methanol synthesis ( Figure 5) and various materials, a plot of the ratio of web width to side length of the recess on the x-axis (horizontal axis) against the permissible stack height between cooling levels in mm at a 5K temperature difference on the y-axis (vertical axis). The left vertical line indicates the limit of weldability, the right vertical line the limit of the catalyst filling. Figures 4 and 5 In the symbols for the measured values, the "triangle" represents nickel as the material, the "vertical x" represents structural steel, the "x" represents titanium, the "circle" represents stainless steel, and the "hyphen" represents a nickel-based material. These examples result in an ideal ratio of web width to side length of the recess between 0.25 and 0.45.

[0126] Figure 6 shows alternative embodiments of the diamond structure preferred according to the invention in plan view. Figure 6ashows a single structural layer 2 and Figure 6b the view of several structural layers arranged one above the other 2. A reinforced web in the middle of the recess provides increased surface areas for the nodes 6 provided, so that the proportion of catalyst volume within the structure is not significantly reduced, but the heat flow through the stack of different structural layers can be further increased. This can be particularly advantageous for highly active catalysts.

[0127] Figure 7 shows the measurement data described in Example 2. Time is plotted on the x-axis (in the format hh:mm:ss), temperature in °C on the y-axis on the left, and methane selectivity on the y-axis on the right. List of reference symbols:

[0128] 1Sectional view of reactor 2Structural layer(s) (or material foil) 3Recess 4Bridge 5Edge(area) 6Contact point (of superimposed structural layers) A(Flow direction from) reaction medium Examples:

[0129] The invention will now be further illustrated with reference to the following non-limiting examples. In each of the experiments, several reactors according to the invention were arranged one above the other to form a multiple reactor arrangement according to the invention. The multiple reactor arrangements in the two examples were constructed almost identically.

[0130] The reactors differed only in the number and thickness of the structural layers (films) and the stacking configuration. The common data are: Catalyst bed / structure length 283 mm Catalyst bed / structure width 65 mm Square cutouts with 6 mm web width 1.5 mm

[0131] The stacking sequence for methanol synthesis (Example 1) from top or bottom: 2 pairs of structural layers (reaction film) 0.6 mm thick with an intermediate and final cover layer (unstructured plate) 1 mm thick. A cooling film pair according to the state of the art (DE 10 2015 111 614 A1, Figure 2- these are always referred to as such in the following) 4 pairs of structural layers (reaction film) 0.6 mm thick, each with a cover layer (unstructured plate) 1 mm thick in between and a final cover layer (unstructured plate) 1 mm thick. A pair of cooling films according to the state of the art. 4 pairs of structural layers (reaction film) 0.6 mm thick, each with a cover layer (unstructured plate) 1 mm thick in between and a final cover layer (unstructured plate) 1 mm thick. A pair of cooling films according to the state of the art. 4 pairs of structural layers (reaction film) 0.6 mm thick, each with a cover layer (unstructured plate) 1 mm thick in between and a final cover layer (unstructured plate) 1 mm thick. A pair of cooling films according to the state of the art. 4 pairs of structural layers (reaction film) 0.6 mm thick, each with a cover layer (unstructured plate) 1 mm thick in between and a final cover layer (unstructured plate) 1 mm thick.6 mm thick with an intermediate and final cover layer (unstructured plate) 1 mm thick. A pair of cooling foils according to the state of the art. 2 pairs of structural layers (reaction foil) 0.6 mm thick with an intermediate and final cover layer (unstructured plate) 1 mm thick.

[0132] The stacking sequence for Fischer-Tropsch synthesis (Example 2) from top or bottom: 3 pairs of structural layers (reaction film) 0.6 mm thick with a cover layer (unstructured plate) 0.4 mm thick in between each pair. One cooling film pair according to the state of the art. 5 pairs of structural layers (reaction film) 0.6 mm thick with a cover layer (unstructured plate) 0.4 mm thick in between each pair. One cooling film pair according to the state of the art. 5 pairs of structural layers (reaction film) 0.6 mm thick with a cover layer (unstructured plate) 0.4 mm thick in between each pair. One cooling film pair according to the state of the art. 5 pairs of structural layers (reaction film) 0.6 mm thick with a cover layer (unstructured plate) 0.4 mm thick in between each pair. One cooling film pair according to the state of the art. 5 pairs of structural layers (reaction film) 0.6 mm thick with a cover layer (unstructured plate) 0.4 mm thick in between each pair.4 mm thick A cooling foil pair according to the state of the art 5 pairs of structural layers (reaction foil) 0.6 mm thick with an intermediate and final cover layer (unstructured plate) 0.4 mm thick A cooling foil pair according to the state of the art 3 pairs of structural layers (reaction foil) 0.6 mm thick with an intermediate and final cover layer (unstructured plate) 0.4 mm thick. Example 1 (methanol synthesis):

[0133] The multiple reactor arrangement was operated in a MeOH synthesis starting from CO 2 and H 2 at 30 bar and 250°C. The reaction feed with a molar ratio of H 2 :CO 2 of 3 (stoichiometric according to the reaction) was preheated to the reaction temperature at a total flow rate of 120 to 140 L / min (at standard conditions) and fed into the multiple reactor arrangement.

[0134] The multiple reactor arrangement was filled with 257 g of industrially available, highly active Cu / ZnO / Al2O3 catalyst with a particle size of 200-400 µm. Unreacted reactant was recycled to 90% after separation of methanol and reaction water using a compressor. The conversion rate was thus over 90% due to the recirculation. Between 100 and 150 ml of methanol were produced per hour. The multiple reactor arrangement was operated with a boiling water circuit at elevated pressure to cool the reaction. No catalyst deactivation was observed over several hundred hours, which would be possible if temperature gradients were to occur in the reactors. Example 2 (Fischer-Tropsch synthesis):

[0135] The multiple reactor arrangement was operated in a Fischer-Tropsch synthesis starting from CO and H2 at 20 bar and a target temperature of 215°C. The reaction feed consisted of 20.6 L / min CO and 44.3 L / min CO diluted with 21.4 L / min N2 (all data at standard conditions). The feed was preheated to approximately the reaction temperature (210°C) and fed into the multiple reactor arrangement. The multiple reactor arrangement was filled with 450 g of highly active industrially produced cobalt catalyst with a particle size fraction of 50 to 200 µm. Heat was again removed using a boiling water circuit. The temperatures in the catalyst beds were recorded along the reaction coordinate. The temperatures varied between 216.9°C and 220.4°C, with the water boiling point at 213°C.Thus, the temperature differences were within the expected range, taking into account the measurement errors (+3°C within the bed; +7°C between the water temperature and the catalyst; the latter value is not crucial, as it influences heat transfer through the wall between the two fluids, thus apparently slightly increasing the gradient.) Since the multiple reactor arrangement was operated in single-pass mode (one pass without recycling of unconverted gas) in this example, the CO conversion could be determined in one reactor pass. This was approximately 69%. Figure 7shows the four recorded temperatures as well as the methane selectivity curve when the target temperature was changed from 212°C to 218°C under otherwise identical conditions. A rapid adaptation of the reaction temperature is evident when the boiling pressure of the water cooling system was changed, without thermal runaway. Furthermore, with the dilution with N2 (reduced CO partial pressure), the methane selectivity value (at an average temperature of 220°C) was within the expected value of 15% for isothermal operation. The measurement of the methane selectivity is shifted on the time axis due to the acquisition in the analytical unit with the intervening volumes of the separation vessels for the liquid and waxy products.

[0136] Selectivity was therefore used to evaluate heat removal from the reaction system, because the selectivities to the various products vary depending on the degree of isothermal energy achieved in the catalyst zone. The heat removal results showed that the expected properties were met. The achieved methane selectivity values ​​indicate that no undetected hot spots exist.

Claims

1. Reactor with multilayer structure comprising - an upper fluid-tight cover layer, - a lower fluid-tight cover layer, - fluid-tight side walls and at least one reaction space located therebetween, which is defined by several superimposed structural layers parallel to the cover layers, wherein - the individual structural layers each have a structure of parallelograms arranged periodically in several rows, each arranged edge-to-edge, and wherein the areas of the parallelograms are designed as openings and their edges are designed as webs, - each structural layer is offset by a factor of 0.5±0.2 and 0.5±0.2 in the x and y directions relative to the layer above and below it respectively, wherein the largest edge length of the parallelograms is standardised as 1 and specifies the x direction and the y direction is orthogonal to this in the plane of the structural layer, - the side edges of the parallelogram structures in the structure layers are arranged rotated by 30 to 60° in relation to the front and rear sides of the reactor, resulting in incomplete parallelogram structures with openings not completely surrounded by webs at the front and rear sides of the reactor, - the reaction space is laminary flowed against from the front side of the reactor, wherein the flowing-against fluid flows into the openings that are not completely surrounded by webs, - the front and rear sides of the reactor are configured for the inflow and outflow of reaction medium, - the cover and structural layers are made of material with good thermal conductivity, - the contact points and areas of the webs of the superimposed structural layers are fully connected to each other, - catalyst bed can be arranged, preferably is arranged, in the openings between the webs of the structural layers, - and wherein the overlap of the openings of one layer by the webs of the overlying layer is 30-60%, and - wherein the material with good thermal conductivity is a material with a thermal conductivity of from 10 to 400 W / (mK).

2. Reactor according to claim 1, characterised in that - the structural layers each have a thickness of 0.3 mm to 2 mm, preferably 0.5 mm to 1 mm, - the web width is from 0.5 mm to 4 mm, preferably from 1 mm to 3 mm, - the largest side length of the openings is between 2 mm and 20 mm, preferably between 4 mm and 12 mm, with the proviso that the openings are wider than the web width by at least a factor of 2, preferably at least a factor of 3.

3. Reactor according to one of the preceding claims, in particular according to claim 1, characterised in that the ratio of the web width to the longest side length of the openings is between 0.15 and 0.55, preferably between 0.25 and 0.45.

4. Reactor according to one of the preceding claims, in particular according to claim 1, characterised in that it has an empty volume portion of 45 vol.% to 75 vol.%, preferably 50 vol.% to 70 vol.%, particularly preferably 60 vol.% to 70 vol.%.

5. Reactor according to one of the preceding claims, characterised in that 2 to 10 structural layers, and in particular for a maximum of 15K, preferably a maximum of 5K, temperature lift, between 2 and 7, preferably between 3 and 6, structural layers are arranged between the cover layers.

6. Reactor according to one of the preceding claims, characterised in that the structural layers additionally have one or more edges on the front and rear sides with incorporated channels for distributing the reaction medium during inflow and outflow.

7. Reactor according to one of the preceding claims, characterised in that, in addition to the cover layers and the structural layers, the reactor also has intermediate layers which are arranged between structural layers, with the proviso that at least two structural layers are arranged on each side of an intermediate layer before a further intermediate layer or a cover layer is arranged.

8. Reactor according to one of the preceding claims, characterised in that the webs are widened at the points at which they are in contact with those of the underlying or overlying structural layers, preferably as circular widenings, and preferably one widening in the centre of each web.

9. Multiple reactor arrangement comprising several reactors according to one of the preceding claims, characterised in that a plurality of reactors are stacked, wherein heat exchanger elements are arranged between the individual reactors in each case.

10. Method for manufacturing a reactor according to one of claims 1 to 8, characterised in that it is produced by 3D printing or superimposing and then welding the individual layers, preferably by means of laser welding or diffusion welding, and optionally catalyst bed is arranged in the openings between the webs of the structural layers.

11. Method according to claim 10, characterised in that I) individual structural layers are produced, preferably by punching, laser cutting, water jet cutting or milling out the structure from a piece of material, a sheet of material or a foil of material, IIa1) several structural layers are arranged offset to each other, one above the other and between an upper cover layer and a lower cover layer, and IIa2) the resulting multilayer stack is joined together by diffusion welding via the respective contact points and contact areas, or IIb1) in each case a structural layer is arranged over a previous cover layer or structural layer, then IIb2) the contact points and / or contact areas are joined together by means of laser welding, IIb3) steps IIb1) and IIb2) are repeated according to the desired number of structural layers, and IIb4) a final cover layer is applied and welded, wherein the individual structural layers are arranged in such a way that the overlap of the openings from one layer to the next is 30-60%, preferably 30 to 55%.

12. Method according to claim 11, characterised in that step IIb4) is replaced by the steps: IIb4a) an intermediate layer is applied and welded, IIb4b) steps IIb1) and IIb2) are carried out in accordance with the desired number of structural layers arranged after the intermediate layer, IIb4c) steps IIb4a) and IIb4b) are repeated as often as intermediate layers are to be arranged, and IIb4z) a final cover layer is applied and welded.

13. Method according to one of claims 10 to 12, characterised in that the structural layers have an edge running around the structure during production, which is preferably removed after welding.

14. Method according to claim 13, characterised in that subsequently to the other steps openings for the fluid inlet and outlet are milled into the front and rear sides of the structural layers.

15. Use of a reactor according to one of claims 1 to 8 or a multiple reactor arrangement according to claim 9 or a reactor manufactured according to one of claims 10 to 14 for exothermic or endothermic reactions, preferably exothermic reactions, particularly preferably methanol synthesis or methanisation or Fischer-Tropsch syntheses, in particular Fischer-Tropsch syntheses.