A reactor for carrying out chemical reactions

Abstract

The invention relates to a reactor for carrying out chemical reactions in a process fluid, which uses M-phase alternating currents for heating the process fluid. The reactor comprises: a reactor wall; at least one group of M reaction tubes, each of which has an electrically heatable heating section of a respective heating length extending between a first removal region and a second removal region, each heating section having a respective feed region in a region extending over 20% to 80% of the heating length of the heating section; electrically conductive feed elements, wherein each group M is assigned a feed element connected to the feed region of the group, and different phases of an alternating current can be fed into different feed elements assigned to a group; electrically conductive first and second removal elements, each group being assigned M first and M second removal elements connected to the first or second removal region of the group; and at least one first star bridge and at least one second star bridge, wherein each group is assigned a first star bridge and a second star bridge, wherein for each group the first removal elements assigned to the group are connected to the first star bridge assigned to the group; and the second removal elements assigned to the group are connected to the second star bridge assigned to the group.

Description

Technical Field

[0001] This invention relates to a reactor for carrying out chemical reactions in a process fluid, which uses a multiphase alternating current to heat the process fluid. Background Technology

[0002] In a range of processes in the chemical industry, reactors are used in which one or more reactants are conducted through heated reaction tubes and undergo catalytic or non-catalytic conversion. Heating serves, in particular, to overcome the activation energy requirement for the chemical reaction to occur. After overcoming the activation energy requirement, the reaction can proceed either endothermally or exothermally. This invention relates particularly to strongly endothermic reactions.

[0003] Examples of these processes are steam cracking, various reforming processes, especially steam reforming, dry reforming (carbon dioxide reforming), mixed reforming processes, and processes for alkane dehydrogenation. In steam cracking, the reaction tubes are guided through the reactor in the form of a coiled tube with at least one U-bend in the reactor, while in steam reforming, tubes that typically extend through the reactor without a U-bend are used.

[0004] This invention is applicable to all these processes and embodiments of the reaction tubes. Illustratively, reference is made to the articles “Ethylene,” “Gas Production,” and “Propenes” in Ullmann’s Encyclopedia of Industrial Chemistry, for example, publication DOI: 10.1002 / 14356007.a10_045.pub2 dated April 15, 2009, publication DOI: 10.1002 / 14356007.a12_169.pub2 dated December 15, 2006, and publication DOI: 10.1002 / 14356007.a22_211 dated June 15, 2000.

[0005] Traditionally, the reaction tubes of the corresponding reactor are heated using a burner. The reaction tubes are guided through a combustion chamber where a burner is also arranged.

[0006] Currently, there is a growing demand for the production of syngas and hydrogen with little or no local CO2 emissions. However, processes using combustion reactors, based on the typical combustion of fossil fuel carriers, cannot meet this demand. Other processes are rejected, for example, due to their high cost. The same applies to the production of olefins and / or other hydrocarbons via steam cracking or alkane dehydrogenation. In these cases, there is also a desire for processes with at least minimal on-site CO2 emissions.

[0007] WO 2015 / 197181 A1 discloses a reactor in which a fluid flowing through a pipe is heated, wherein the conductive pipe is connected to multiple phases of an alternating current source to form a star-shaped circuit and generate heat according to the resistance of the pipe.

[0008] In terms of design, the length of the heated tube and therefore the ohmic resistance are limited. The result is a high-current and low-voltage power source to introduce the required heating power into the tube, which necessitates a high-current feed that is mechanically and materially complex. Summary of the Invention

[0009] This objective is achieved by a reactor for carrying out a chemical reaction, the reactor having the features of the independent claim.

[0010] The present invention employs a method where each reactor is connected to only one phase, and phase balance is established through multiple reactors. Compared to an arrangement where reactors are connected to multiple phases, the length heated by each phase in the reactor, and therefore the resistance, increases. This enables higher power input at a constant current intensity (because P = R·I). 2 Where P: power, R: resistance, i: current intensity), this can be achieved by increasing the voltage. Since there is only one current feed for each reactor via the corresponding feed element, the number of technically complex high-current feeds and the power losses that occur therein can be reduced.

[0011] A reactor for carrying out chemical reactions in a process fluid, which uses a multiphase alternating current to heat the process fluid, wherein the alternating current has a number of M phases, where M is an integer greater than 1, the reactor comprising: a reactor vessel formed by insulated reactor walls; and at least one group having a plurality of reaction tubes, wherein each group comprises M reaction tubes, each of the M reaction tubes having an electrically heatable heating section extending a corresponding heating length between a first removal region and a second removal region of the respective reaction tube, wherein the heating section is arranged within the reactor vessel for at least 95% of its heating length and each has a feed region in a region extending beyond 20% to 80% of the heating length of the heating section; the percentage "20% to 80%" in the specification refers to the position within the heating length, that is, 0% represents the position of the first (or second) removal region, 50% represents the middle of the heating section, and 100% represents the position of the second (or first) removal region (i.e., not intended as a percentage).

[0012] In the feed region, connected to the power source via feed elements, in each case, one phase of the alternating current is fed or supplied to the heating section; that is, an alternating voltage corresponding to the corresponding phase is applied. In the removal region, connected to the star bridge via removal elements, the corresponding phase of the alternating current is removed or released from the heating section. The star bridge is used to balance the different phases of the alternating current.

[0013] The fact that the reaction tube is electrically heatable or has an electrically heatable heating section means that the material used for the reaction tube, and especially the heating section, is a material with electrical conductivity suitable for electric heating. Examples are heat-resistant steel alloys, particularly heat-resistant chromium-nickel steel alloys. These steel alloys can also be used for electrical connections (through which current is conducted to the reactor vessel), i.e., feed elements and removal elements. For example, materials with standard names according to DIN EN 10027, Part 1, “Materials” can be used: GX40CrNiSi25-20, GX40NiCrSiNb35-25, GX45NiCrSiNbTi35-25, GX35CrNiSiNb24-24, GX45NiCrSi35-25, GX43NiCrWSi35-25-4, GX10NiCrNb32-20, GX50CrNiSi30-30, G-NiCr28W, G-NiCrCoW, GX45NiCrSiNb45-35, GX13NiCrNb45-35, GX13NiCrNb37-25, or GX55NiCrWZr33-30-04.

[0014] The region enclosed by the reactor wall is surrounded by at least one reactor wall in all spatial directions. Typically, the reactor wall is formed by multiple individual walls connected together in a manner that encloses the region. Therefore, it can also be referred to as a set of reactor walls, but for simplicity, the term "reactor wall" is used. The enclosed region, and therefore the reactor wall, can have any volumetric shape, but is preferably a square prism shape. The reactor wall can have sealed structural elements (e.g., feedthroughs or observation windows), but can also have permanently open and / or closable openings, preferably for conditioning the atmosphere within the reactor wall, as connections to other parts of the apparatus, such as inert gas inlet nozzles or outlet openings leading to a chimney duct.

[0015] The reactor walls form the reactor vessel (which may also be called a reactor box); that is, the reactor walls constitute one or more walls of the reactor vessel. Therefore, the term "reactor wall" should not be understood here as referring to a box for the process fluid. The area enclosed by the reactor walls is the interior of the reactor vessel. In the remainder of the description, for simplicity, the area inside the reactor vessel (i.e., within the reactor vessel) is also referred to as "inside the reactor walls." The expression "inside the reactor walls" therefore refers to the area enclosed by the reactor walls. Similarly, the area outside the reactor vessel is also referred to as "outside the reactor walls."

[0016] The reactor wall reduces heat loss and protects the reactor vessel or its surroundings from heat. Therefore, the heating length should be substantially within the area enclosed by the reactor wall, i.e., inside the reactor vessel, according to the invention at least 95%, preferably at least 98%, and more preferably 100% (i.e., the heating section is completely within the area enclosed by the reactor wall). This arrangement is preferably symmetrical; that is, if there are sections (where the heating section is not 100% within the area enclosed by the reactor wall), those sections outside the reactor vessel are arranged symmetrically with respect to the heating length. Specifically, the removal area may be located outside the reactor wall.

[0017] In each case, the feeding region is preferably arranged in a region extending from 30% to 70% of the heating length of the heating section, more preferably in a region extending from 40% to 60% of the heating length of the heating section, and most preferably in a region extending from 45% to 55% of the heating length of the heating section. This corresponds to a symmetrical division of the current from the feeding region to the first removal region and the second removal region.

[0018] The reactor also includes conductive feed elements, wherein each group is allocated M feed elements electrically connected to a feed area of ​​that group, wherein different phases of alternating current are fed or can be fed to different feed elements allocated to that group. The feed elements extend through the reactor wall and, in principle, constitute an electrical feed or electrical connection. The reactor also includes conductive first and second removal elements, each group being allocated M first removal elements and M second removal elements electrically connected to a first or second removal area of ​​that group; the removal elements are used to dissipate the current supplied via the feed elements and feed areas. The feed elements act as high-current feeds.

[0019] Conductive connections between feed elements and feed areas or between removal elements and removal areas can be made using form-fit connections, force-fit connections (e.g., sleeves), or integral connections (e.g., welded connections), where combinations are conceivable.

[0020] The reactor also includes at least one conductive first starbridge and at least one conductive second starbridge, wherein each group is assigned a first starbridge and a second starbridge, wherein, for each group, a first removal element assigned to that group is conductively connected to the first starbridge assigned to that group, and a second removal element assigned to that group is conductively connected to the second starbridge assigned to that group. Potential balance between phases is established through the starbridges.

[0021] Preferably, at least one first starbridge and at least one second starbridge are arranged outside the reactor vessel. One advantage of arranging the starbridges outside the reactor vessel (i.e., outside the reactor wall) is that materials with lower heat resistance can be used there than are necessary for arrangements inside the reactor vessel. Therefore, materials with high electrical conductivity, such as copper, can be selected.

[0022] Therefore, between different phases, i.e., between different reaction tubes, the resistance across the star bridge is significantly less than the resistance across the connection formed by the fluid supply pipes and fluid supply manifolds connected to the reaction tubes or the fluid discharge pipes and fluid discharge manifolds connected to the reaction tubes. A fluid supply pipe refers to the pipe through which process fluid is supplied to the corresponding reaction tube; correspondingly, a fluid discharge pipe refers to the pipe through which process fluid is discharged from the corresponding reaction tube. A fluid supply manifold is a pipe connected to multiple supply pipes for distributing process fluid from other parts of the unit to multiple reaction tubes. A fluid discharge manifold is a pipe connected to multiple discharge pipes for collecting material from multiple reaction tubes after a chemical reaction for further transfer to other parts of the unit. The fluid supply pipes, together with the fluid supply manifolds, are referred to as a fluid supply pipe assembly or supply manifold; the fluid discharge pipes, together with the fluid discharge manifolds, are referred to as a fluid discharge pipe assembly or discharge manifold. The fluid supply pipe assembly and the fluid discharge pipe assembly respectively form electrical connections between the reaction tubes parallel to the first and second star bridges.

[0023] Preferably, for the circuit spanning the fluid supply pipe assembly and / or the fluid discharge pipe assembly, the resistance between two reaction tubes in the group spanning the first star bridge and / or the second star bridge is at most 50%, more preferably at most 25%, and most preferably at most 10% of the resistance parallel to them.

[0024] This is particularly advantageous because the potential balance is essentially achieved via a star bridge in this case, thereby reducing the potential difference between the fluid supply pipe assembly and the fluid discharge pipe assembly, which could lead to current flowing through components of the device outside the reactor.

[0025] Preferably, the first removal zone and the second removal zone are arranged inside the reactor vessel, wherein the first removal element and the second removal element have elongated shapes and extend through the reactor wall; wherein, more preferably, the heating section is arranged entirely inside the reactor vessel. This reduces heat loss.

[0026] Preferably, if one of the first bridges in at least one first bridge is assigned to multiple groups, then the same second bridge is assigned to those multiple groups.

[0027] Furthermore, for at least one group, the first and second starbridges assigned to that group are electrically connected to each other via bridge connectors. This allows for the balancing of potential differences between the starbridges. If at least one group comprises multiple groups, this arrangement can exist for different groups.

[0028] The reactor preferably includes one or more alternating current sources, wherein each alternating current source provides alternating current having M phases on M phase lines (U, V, W); wherein each group is assigned one of the one or more alternating current sources; wherein, for each group, the feed element assigned to that group is connected to the phase line of the alternating current source assigned to that group.

[0029] Preferably, at least one star point is formed in at least one of one or more alternating current sources, wherein, for at least one group of alternating current sources, a first star bridge and / or a second star bridge assigned to that group are connected to the star point of the alternating current source assigned to that group via one or more neutral conductors (N). This allows for specific variations in current intensity between phases.

[0030] Preferably, one of the one or more AC current sources is assigned to multiple groups, wherein the multiple groups are assigned the same first star bridge and the same second star bridge.

[0031] Each of the heating sections has multiple straight pipe sections connected to each other by one or more U-shaped bends, wherein, more preferably, the number of pipe sections is even. Thus, a coil of tubes is formed, which enables a compact design of the reactor.

[0032] The feeding areas are preferably all located at one of the U-bends in the U-shaped channel. Since the U-bend is located on the outside, close to the reactor wall, the high current feed formed by the feeding elements can be kept relatively short.

[0033] Preferably, the removal elements are connected to electrically insulating retaining devices for connection to the support structure, wherein the retaining devices are electrically insulatingly connected to the respective removal elements and / or the retaining devices themselves are electrically insulating. Specifically, if the removal elements extend through the reactor wall, they can also serve a load-bearing function. For example, the support structure is a portion of the production apparatus in which the reactor is installed.

[0034] Furthermore, for each reaction tube, preferably at least one support device is provided for connection to the support structure, wherein the support device is connected to the reaction tube in an electrically insulating manner and / or is electrically insulating itself, and is further preferably located in one of the U-shaped bends.

[0035] Preferably, all feed passages through the reactor wall, including those for the removal elements and for the fluid discharge and supply pipes, are made airtight by means of suitable equipment (e.g., sealed bellows). This airtight equipment is designed to be electrically insulated so that there is no electrical contact between the feeded components and the reactor wall. Such equipment can also be provided for performing current feeding (i.e., for the feed elements), particularly if only small thermal equilibrium shifts occur, for example, when the current feed is arranged at the top. Figure 2 As shown.

[0036] The phase shift between two distinct phases of an alternating current, expressed in radians, is 2π·k / M, where k is an integer ranging from 1 to M⁻¹ in each case. In the case of a symmetrical load, the phases thus cancel each other out at the star point or in the star bridge.

[0037] The chemical reaction can be a chemical reaction that takes place at least partially at a temperature in the range of 200°C to 1700°C, particularly 300°C to 1400°C or 400°C to 1100°C. Preferably, the chemical reaction occurs at least partially at a temperature of at least 500°C, more preferably at a temperature of at least 700°C, particularly in the temperature range of at least 500°C or 700°C to 1100°C. Therefore, the provided voltage / current is suitable for providing appropriate heating power. The reactor and power source are also configured to carry out the chemical reaction at these temperatures and provide corresponding heating power. Preferably, the chemical reaction is one of the following: steam cracking, steam reforming, dry reforming (carbon dioxide reforming), propane dehydrogenation, or a reaction with hydrocarbons, typically at least partially above 500°C.

[0038] The invention is first described with reference to reaction tubes and reactors used for steam cracking or steam reforming. However, the invention can also be used in other reactor types. Generally, as mentioned, the reactor proposed according to the invention can be used for all endothermic chemical reactions.

[0039] The invention will now be explained in more detail with reference to the accompanying drawings, which illustrate embodiments of the invention. Attached Figure Description

[0040] Figure 1 A perspective view of a reactor connected to an alternating current source according to a preferred embodiment of the invention is shown.

[0041] Figure 2 A front view of a reactor according to another preferred embodiment of the invention is shown.

[0042] Figure 3 A front view of a reactor according to another preferred embodiment of the invention is shown. Detailed Implementation

[0043] In the accompanying drawings, elements that are structurally or functionally corresponding to each other are indicated by the same or similar reference symbols, and for clarity, they are not repeatedly explained.

[0044] Figure 1 A (large) perspective view of a reactor 2 connected to an alternating current source 10 according to a preferred embodiment of the invention is shown. The reactor 2 has: an insulated reactor wall 4, the outline of which is indicated by dashed lines in the figure; and a plurality of reaction tubes 6u, 6v, 6w through which the process fluid to be heated (in which a chemical reaction will occur) flows. As described above, the reactor wall forms the reactor vessel. The reaction tubes form groups. The number of reaction tubes (in a group) corresponds to the number of phases of the alternating current source; here, for example, three phases, although another number greater than or equal to two is also possible. Typically, multiple groups of reaction tubes can be provided, wherein the number of reaction tubes in each group corresponds to the number of phases. In this general case, one or more alternating current sources can be provided, wherein the phase terminals of one alternating current source can also be connected to reaction tubes in different groups, i.e., one alternating current source may supply alternating current to one or more groups of reaction tubes; these one or more groups are assigned alternating current sources to which alternating current is supplied.

[0045] Each of the reaction tubes 6u, 6v, and 6w has a heating section 20 that extends between the first removal region 22 and the second removal region 23. For clarity of the drawings, reference numerals are used only herein and hereinafter to denote one of several similar elements. The length of the reaction tube between the first removal region 22 and the second removal region 23 (i.e., the heating section 20) is called the heating length. This extends here over several turns of the tube coil formed by each of the reaction tubes. The heating section 20 of each reaction tube is arranged within the reactor wall 4.

[0046] More generally, remove regions 22 and 23 (and) Figure 1(Different) may also be located outside the reactor wall; in this case, shown in Figure 2 In this process, the heating section extends through the reactor wall (wherein, the section of the heating section located outside the reactor wall should be as small as possible to avoid heat loss), wherein the heating section should be located inside the reactor wall for at least 95% of its heating length.

[0047] For at least a majority of the area of ​​reactor 2 through which the heating section for heating the process fluid travels, reactor wall 4 forms a substantially closed shell (except for feedthroughs for supplying or discharging process gases, feeding or removing current, etc.). The supply and removal of the process fluid are carried out via fluid supply pipe 26 or fluid discharge pipe 27 connected to the reaction tubes, each of which is connected to a fluid supply manifold 28 or fluid discharge manifold 29. Through the fluid supply manifold 28 or fluid discharge manifold 29, the process fluid is transferred from one of the other production unit components to the reactor and discharged from the reactor to these production unit components after the chemical reaction. Fluid supply pipe 26, together with fluid supply manifold 28, forms a so-called supply manifold (fluid supply assembly); fluid discharge pipe 27, together with fluid discharge manifold 29, forms a so-called discharge manifold (fluid discharge assembly).

[0048] Approximately midway through the heating length between the first removal region 22 and the second removal region 23, more generally between 20% and 80%, each reaction tube 6u, 6v, 6w, or its corresponding heating section 20, has a feed region 24. Each of the feed regions 24 is electrically connected to a conductive feed element 32, which in turn is electrically connected to the phase or phase line U, V, W of the alternating current source 10. The feed element 32, representing a current terminal, extends through the reactor wall 4 and has, for example, an elongated shape, with one end connected to the corresponding feed region 24 and its other end connected to one of the phase lines U, V, W. Feed elements connected to a group of feed regions are distributed to that group.

[0049] The alternating current source 10 preferably provides a multiphase alternating current with a predetermined alternating voltage, here, a three-phase alternating current. More generally, different numbers M of phases are also conceivable. Preferably, the phase shift between phases is chosen such that the voltage or current cancels each other out at the star point, i.e., the phase shift between two arbitrary phases can be expressed in radians as 2π·k / M or in degrees as 360°k / M, where k is an integer in the range of 1 to M-1. In the case of three phases, it is therefore 2π / 3 or 4π / 3, corresponding to 120° or 240°. In this case, a phase difference is obtained between two consecutive phases, i.e., k=1, with a phase difference of 2π / M.

[0050] The AC current source 10 can be designed as an AC current transformer, particularly a high-current transformer. Here, only the primary side (i.e., the AC current source of power source 10) from a public power grid or generator is shown in shaded boxes, symbolizing the primary transformer coil 12. The primary power supply line is not shown in the figure. The primary AC voltage can typically be several hundred to several thousand volts (e.g., 400V, 690V, or 1.2kV). At least one additional transformer (not shown; possibly at least one regulating transformer that allows control of the secondary AC voltage or adjustment within a specific voltage range) can be inserted between the primary side of power source 10 and the possible public power grid or generator to obtain a suitable input voltage for the high-current transformer. Alternatively, or in addition to such inserted transformer, the input voltage can also be set by means of one or more thyristor power controllers.

[0051] On the secondary side, phase lines or phase terminals U, V, W are provided, on which the phase of the alternating current is supplied. Electrical power is supplied to the phase lines U, V, W via a secondary-side transformer coil (not shown in detail) (only the phase lines extending through the primary-side transformer coil 12 are shown to indicate their electromagnetic interaction with each other). The secondary-side AC voltage can conveniently be in the range up to 300V (e.g., less than 150V or less than 100V, or even less than or equal to 50V). The secondary side is electrically isolated from the primary side.

[0052] Phase lines U, V, and W are connected to each other in the AC current source 10 to form a star point 14 of the AC current source 10. Grounding of this star point 14 is preferably omitted. Star point 14 may optionally be connected to the neutral conductor N.

[0053] The first removal region 22 is electrically connected to a conductive first removal element 34, which in turn is electrically connected to each other via a conductive first star bridge 36. The second removal region 23 is electrically connected to a conductive second removal element 35, which in turn is electrically connected to each other via a conductive second star bridge 37. Removal elements connected to a group of removal regions are assigned to that corresponding group.

[0054] Preferably, the first removal element 34 and the second removal element 335 extend through the reactor wall 4, wherein, more preferably (e.g. Figure 1 As shown), the first star bridge 36 and the second star bridge 37 are located outside the reactor wall 4. If the removal area is outside the reactor wall, the removal element does not extend through the reactor wall.

[0055] Furthermore, a retaining device 40 is preferably provided to be connected to the removal elements 34, 35, and the retaining device 40 is electrically insulated from and / or itself from the removal elements 34, 35. The removal elements may in this case have an elongated shape, wherein the removal end of the removal element is connected to the removal area, and the opposite retaining end is connected to the retaining device. The retaining devices 40 are configured to be connected to a support structure (not shown) of a production apparatus in which a reactor is mounted. They are therefore specifically used to fix or support the reaction tubes (and the elements connected to them). Additionally or alternatively, a support device (not shown) connected to the heating section 20 may be provided, which is electrically insulated from and / or itself from the heating section 20, and extends through the reactor wall to connect to the support structure, such that the reaction tubes are held by means of the support device.

[0056] Alternating current is thus fed or introduced into the heating section 20 via feed region 24, and removed from the latter via removal regions 22, 23. Starting from feed region 24 of the heating section 20, the current flows first to the first removal region 22 and then to the second removal region 23 according to the corresponding resistance. Since the different reactance tubes 6u, 6v, 6w are fed with different phases U, V, W of the alternating current, potential balance ideally occurs in the two star bridges 36, 37 (i.e., with symmetrical loads) when there is a corresponding phase shift between the phases. In terms of the circuit, the star bridges form the star point on the consumer side.

[0057] Optionally, a neutral conductor N or more neutral conductors are provided, through which star bridges 36, 37 are electrically connected to the alternating current source 10.

[0058] Preferably, at least one conductive bridge connector 38 is also provided, which is electrically connected to both the first starbridge 36 and the second starbridge 37.

[0059] Figure 1 The illustrated reaction tubes 6u, 6v, 6w, or their heating sections 20, are designed as tube coils, i.e., including straight tube sections 42 connected to each other via a lower U-bend 44 and an upper U-bend 45. In the illustrated embodiment, feed regions 24 are provided at the lower U-bend. A first removal region 22 and a second removal region 23 are here, for example, arranged at the upper end of the tube section 42 in an elbow region, where corresponding tube sections 42 overlap with the fluid supply tube 26 and the fluid discharge tube 27, respectively. However, removal and feed regions may also be provided in other regions of the tube coil.

[0060] In the example shown, the length of the section between the feed region 24 and either the first removal region 22 or the second removal region 23 comprises three straight pipe sections in each case, and is therefore significantly longer than pipes (as in the prior art) that are connected to three phases (more precisely, to one phase at each lower U-bend) and whose straight pipe sections are electrically connected to each other at their opposite ends. That is, the length of the reaction tube connected to one phase is approximately three times longer and has a correspondingly higher resistance. At a constant current intensity, each phase and reaction tube therefore generates a correspondingly higher heating power, specifically, requiring less high-current feed.

[0061] The terms “top” and “bottom” refer only to the orientation shown in the diagram; that is, they are used to distinguish the corresponding U-bends. The actual orientation of the tube coil (i.e., relative to the Earth’s gravitational field) can also be different; for example, the tube coil can be lowered (the tube section travels horizontally), or the arrangement can be reversed compared to the arrangement shown (removal elements, star bridge, and supply / discharge manifolds at the bottom; feed elements at the top).

[0062] exist Figure 1 In the reaction tubes 6u, 6v, and 6w, each or each heating section 20 has, for example, six straight tube sections 42, i.e., divided into three U-shaped sections, which are connected to each other via an upper U-shaped bend 45. Different numbers are also possible here (e.g., two straight tube sections (one U-shaped section), four straight tube sections (two U-shaped sections); see...). Figure 2 (8 straight pipe sections (2 U-shaped sections), etc.). In principle, an odd number of straight pipe sections is also possible; see Figure 3 .

[0063] exist Figure 1 In each heating section 20, the feed area 24 is located exactly in the middle of the heating length between the first removal area 22 and the second removal area 23. However, deviations are possible; that is, the length of the heating section (first heating section) between the first removal area 22 and the feed area 24 (first heating length) may differ from the length of the heating section (second heating section) between the feed area 24 and the second removal area 23 (second heating length). The current is then shunt according to the resistance of these two sections (first heating section / second heating section) to achieve different heating powers in the two sections.

[0064] Figure 1Only one group with multiple (three, as an example) reaction tubes is shown. Typically, a reactor can include multiple such groups, wherein one or more AC current sources can be provided, each providing AC current to one or more groups respectively; that is, the same AC current source is assigned to one or more groups. Multiple first starbridges and multiple second starbridges can also be provided, wherein a single first / second starbridge can be connected to removal elements assigned to different groups; that is, the same first / second starbridge is assigned to these different groups, wherein, preferably, groups assigned the same first starbridge are also assigned the same second starbridge. Preferably, if multiple groups are assigned the same AC current source, then these multiple groups should also be assigned the same first starbridge and the same second starbridge.

[0065] Figure 2 A front view of a reactor 52 according to another preferred embodiment of the invention is shown. Figure 3 Similarly, this diagram is used to illustrate different designs of the reactance tubes or coils and the corresponding connection options for the power source, and therefore only shows one of the reactance tubes and its connection. Other reactance tubes (corresponding to the number of phases of the AC current source) are designed in the same manner as shown, arranged perpendicular to the drawing plane at a certain distance from the shown reactance tube (“parallel displacement”), where the difference lies in that their feed areas are connected to different phases. Details or attributes of elements will not be repeated below unless otherwise specified. Figure 1 The differences in; combination Figure 1 The explanation of the description applies here.

[0066] Reactor 52 again has reactor wall 54 and reaction tubes (arranged in a direction perpendicular to the drawing plane), wherein, as a representative example, only one reaction tube 56u is visible in the front view. Each reaction tube 56u has a heating section 20, which has a heating length extending between a corresponding first removal region 22 connected to the first removal element 34 and a corresponding second removal region 23 connected to the second removal element 35. The first removal element 34 is connected by a first star bridge 36 extending perpendicular to the drawing plane; the second removal element 35 is connected by a second star bridge 37 also extending perpendicular to the drawing plane.

[0067] Each reaction tube 56u or each heating section consists of a straight tube section 42, which are connected to each other by a lower U-bend 44 and an upper U-bend 45 to form a tube coil consisting of 4 straight tube sections (2 U-shaped sections); a similar arrangement with another number of tube sections (e.g., 8 or 12 straight tube sections (4 or 6 U-shaped sections) etc.) is also possible.

[0068] and Figure 1The difference is that, in this case, the feed region 24 is not located in the lower U-bend, but in the upper U-bend 45, that is, again in the middle of the heating section. In other words, the removal regions 22, 23 and the feed region 24 are located on the same side (top) of the reactor. The feed region 24 of the visible reaction tube 56u is connected to the phase line U (not shown in more detail) of the AC current source. Therefore, the feed regions of the other invisible reaction tubes are connected to the other phase lines of the AC current source. Potential balance across different phases occurs again across the star bridges 36, 37, causing the star bridges to again form a consumer-side star point in terms of the circuit.

[0069] Regardless of the shape of the tube coil, Figure 2 In one embodiment, the first removal region 22 and the second removal region 23 are located outside the reactor wall 54. Of course, as... Figure 1 The configuration in which the removal zone is located within the reactor wall is also possible.

[0070] Furthermore, conductive bridge connectors electrically connected to both the first starbridge 36 and the second starbridge 37, and / or one or more neutral conductors connecting the starbridges to the star points of an AC current source, may also be provided. Similarly, holding devices 40 and / or carrying devices may be provided. Most of these components are not shown. Figure 2 middle.

[0071] Figure 3 A front view of a reactor 62 according to another preferred embodiment of the invention is shown. Figure 2 Similarly, this diagram is used to illustrate different designs of the reactance tubes or coils and the corresponding connection options for the power source, and therefore only shows one of the reactance tubes and its connection. Other reactance tubes (corresponding to the number of phases of the AC current source) are designed in the same manner as shown, arranged perpendicular to the drawing plane at a certain distance from the shown reactance tube (“parallel displacement”), where the difference lies in that their feed areas are connected to different phases. Details or attributes of elements will not be repeated below unless otherwise specified. Figure 1 The differences in; combination Figure 1 The explanation of the description applies here.

[0072] Reactor 62 again has reactor wall 64 and reaction tubes (arranged in a direction perpendicular to the drawing plane), wherein, as a representative example, only one reaction tube 66u is visible in the front view. Each reaction tube 66u has a heating section 20 having a heating length extending between a corresponding first removal region 22 connected to the first removal element 34 and a corresponding second removal region 23 connected to the second removal element 35. The first removal element 34 is connected by a first star bridge 36 extending perpendicular to the drawing plane; the second removal element 35 is connected by a second star bridge 37 also extending perpendicular to the drawing plane.

[0073] Each reaction tube 56u or each heating section consists of straight tube sections 42 connected to each other via a lower U-bend 44 and an upper U-bend 45 to form a tube coil. Unlike the previous embodiments, an odd number of straight tube sections 42 are provided (here, for example, 5, although another odd number is also conceivable). In one respect, this results in the first removal region 22 (and correspondingly, the first removal element 34) being arranged at the top, while the second removal region 23 (and correspondingly, the second removal element 35) is arranged at the bottom. See the explanation above for the terms "bottom" / "top".

[0074] On the other hand, this also results in the feed region 24, which is also arranged in the U-bend (e.g., in the upper U-bend 45, although the arrangement in the lower U-bend 44 is also possible), not being located in the middle of the heating section 20 (i.e., not at 50% of the heating length). Instead, the length of the section between the feed region 24 and the first removal region 22 is slightly shorter than the length of the section between the feed region 24 and the second removal region 23. In principle, it is also possible (in all embodiments) to arrange the feed region in the straight pipe section, but arranging it in the U-bend is preferred because this generally means a length of feed element that must conduct current with a high current intensity (e.g., several kA) and therefore the resistance can be kept relatively low, resulting in correspondingly high power losses.

[0075] Figure 3 In one embodiment, the removal area is located within the reactor wall 54, such that the removal element extends through the reactor wall, although embodiments in which the removal area is arranged outside the reactor wall are also obviously conceivable.

[0076] Similarly, one or more neutral conductors can be provided at the star point to connect the star bridge to the AC current source. Figure 3 (Not shown in the image). Similarly, a holding device 40 and / or a carrying device (not shown) may be provided.

Claims

1. A reactor for carrying out a chemical reaction in a process fluid, the reactor using a multiphase alternating current to heat the process fluid, wherein, The alternating current has M phases, where M is an integer greater than 1, and the reactor comprises: The reactor vessel is formed by insulated reactor walls; At least one group having multiple reaction tubes, wherein each group comprises M reaction tubes, wherein each of the M reaction tubes has an electrically heated section (20) extending a corresponding heating length between a first removal region (22) and a second removal region (23) of the respective reaction tube, wherein the heating section is arranged within the reactor vessel for at least 95% of its heating length and each has a feed region (24) in a region extending beyond 20% to 80% of the heating length of the heating section. Conductive feed elements (32), wherein each group is assigned a feed element that is conductively connected to the feed region of the group, wherein different phases of the alternating current are fed or can be fed to different feed elements assigned to the group; Conductive first removal element (34) and second removal element (35), wherein each group is assigned M first removal elements and M second removal elements that are conductively connected to the first removal region or the second removal region of the group; At least one conductive first starbridge (36) and at least one conductive second starbridge (37), wherein each group is assigned a first starbridge and a second starbridge, wherein for each group, the first removal element assigned to the group is conductively connected to the first starbridge assigned to the group, and the second removal element assigned to the group is conductively connected to the second starbridge assigned to the group.

2. The reactor according to claim 1, wherein, The at least one first starbridge (36) and the at least one second starbridge (37) are arranged outside the reactor vessel.

3. The reactor according to claim 2, wherein, The first removal zone (22) and the second removal zone (23) are arranged inside the reactor vessel, and wherein the first removal element (34) and the second removal element (35) have an elongated shape and extend through the reactor wall; wherein the heating section (20) is arranged entirely inside the reactor vessel.

4. The reactor according to any one of the preceding claims, wherein, If one of the at least one first bridges is assigned to multiple groups, then the same second bridge is assigned to those multiple groups.

5. The reactor according to any one of claims 1 to 3, wherein, For one of the at least one groups, the first starbridge (36) and the second starbridge (37) assigned to the group are electrically connected to each other by means of a bridge connector (38).

6. The reactor according to any one of claims 1 to 3, wherein, The reactor includes one or more alternating current sources (10), wherein each alternating current source provides alternating current having M phases on M phase lines; wherein each group is assigned one of the one or more alternating current sources; wherein, for each group, the feed element assigned to the group is connected to the phase line of the alternating current source assigned to the group.

7. The reactor according to claim 6, wherein, At least one star point (14) is formed in at least one of the one or more AC current sources, wherein, for a group of the at least one group, the first star bridge and / or the second star bridge assigned to the group is connected to the star point of the AC current source assigned to the group via one or more neutral conductors (N).

8. The reactor according to claim 6, wherein, One of the one or more AC current sources is assigned to multiple groups, wherein the same first star bridge and the same second star bridge are assigned to the multiple groups.

9. The reactor according to any one of claims 1 to 3, wherein, Each of the heating sections has a plurality of straight pipe sections (42) connected to each other by one or more U-shaped bends, wherein the number of the straight pipe sections (42) is even.

10. The reactor according to claim 9, wherein, Each of the feeding areas is located at one of the U-shaped bends in the U-shaped curve.

11. The reactor according to any one of claims 1 to 3, wherein, The removal element is connected to an electrically insulated retaining device (40) for connection to the support structure, wherein the retaining device is electrically insulated from the corresponding removal element and / or the retaining device itself is electrically insulated.

12. The reactor according to claim 11, wherein, For each reaction tube, at least one carrier device is provided for connection to the support structure, the carrier device being connected to the reaction tube, wherein the at least one carrier device is electrically insulated from the reaction tube and / or the at least one carrier device itself is electrically insulated.

13. The reactor according to claim 9, wherein, The removal element is connected to an electrically insulated retaining device (40) for connection to the support structure, wherein the retaining device is electrically insulated from the corresponding removal element and / or the retaining device itself is electrically insulated.

14. The reactor according to claim 13, wherein, For each reaction tube, at least one support device is provided to connect to the support structure. The support device is connected to the reaction tube, wherein the at least one support device is electrically insulated from the reaction tube and / or the at least one support device itself is electrically insulated, and the at least one support device is located in one of the U-shaped bends of the U-shaped bend.

15. The reactor according to any one of claims 1 to 3, wherein, The phase shift between two distinct phases of the alternating current, expressed in radians, is 2π·k / M, where k is an integer in the range from 1 to M-1 in each case.

16. The reactor according to any one of claims 1 to 3, wherein, The chemical reaction is a chemical reaction that occurs at least partially at a temperature of at least 500°C.

17. The reactor according to claim 16, wherein, The chemical reaction is one of the following: steam cracking, steam reforming, dry reforming, propane dehydrogenation, or a reaction with hydrocarbons at least partially at temperatures above 500°C.

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