A reactor for carrying out a chemical reaction

Abstract

The present invention relates to a reactor that performs a chemical reaction of a process fluid using an M-phase alternating current to heat the process fluid. The reactor comprises a reactor wall and at least one group of M reaction tubes, each reaction tube having an electrically heatable heating zone extending between a first and second removal zone over a corresponding heating length, and each heating zone having a respective feed zone within a zone extending from 20% to 80% of the heating length of the heating zone. The reactor comprises electrically conductive feed elements, each group of reaction tubes M is paired with a feed element connected to the feed zone of the group, and other phases of the alternating current are supplied to other feed elements paired with the group. The reactor comprises electrically conductive first and second removal elements, each group is paired with M first and M second removal elements connected to the first or second removal zone of the group. The reactor comprises at least one first and second star bridge, each group being paired with the first and second star bridges, and for each group, the first removal element paired with the group is connected to the first star bridge paired with the group, and the second removal element paired with the group is connected to the second star bridge paired with the group.

Description

Technology Field

[0001] The present invention relates to a reactor for causing a chemical reaction in a process fluid using multiphase alternating current to heat the process fluid. Background Technology

[0002] In a series of processes in the chemical industry, reactors are used in which one or more reactants react through a heated reaction tube to be converted catalytically or non-catalytically. Heating contributes, in particular, to overcoming the activation energy requirement necessary for a chemical reaction to occur. The reaction may proceed endothermally overall or exothermally after the activation energy requirement has been overcome. The present invention relates particularly to strongly endothermic reactions.

[0003] Examples of such processes include steam pyrolysis, various reforming processes (particularly steam reforming, dry reforming (carbon dioxide reforming), and mixed reforming processes), and alkene dehydrogenation processes. In steam pyrolysis, the reaction tube passes through a reactor in the form of a tube coil, and the reaction tube must have at least one U-bend within the reactor. In contrast, in steam reforming, a tube extending through the reactor without a U-bend is generally used.

[0004] The present invention is suitable for all such processes and reaction tube implementations. For example, one should refer to the articles “ethylene,” “gas production,” “propene,” etc. in Ullmann’s Encyclopedia of Industrial Chemistry. For example, one may refer to DOI: 10.1002 / 14356007.a10_045.pub2 published April 15, 2009, DOI: 10.1002 / 14356007.a12_169.pub2 published December 15, 2006, and DOI: 10.1002 / 14356007.a22_211 published June 15, 2000.

[0005] The reaction tube of the reactor is typically heated using a burner. The reaction tube is passed through a combustion chamber where the burner is located.

[0006] Currently, there is a growing regional demand for synthesis gas and hydrogen produced with zero or reduced carbon dioxide emissions. However, processes utilizing direct-fired reactors based on the combustion of fossil fuels generally fail to meet this demand. Furthermore, other processes are rejected due to high costs. For example, the same requirements regarding carbon dioxide emissions apply when olefins and / or other hydrocarbons are fed via steam pyrolysis or alkene dehydrogenation. In such cases, there is a demand for processes with low carbon dioxide emissions, at least on-site.

[0007] WO 2015 / 197181 A1 disclosed a reactor for heating a fluid flowing through a pipeline. An electrically conductive pipeline is connected to several phases of an AC power source to form a star point circuit, and heat is generated by the electrical resistance of the pipeline.

[0008] The length of the tube being heated and the ohmic resistance are limited by design. As a result, a power supply with high current and low voltage is required to supply the heating output needed for the pipeline, and supplying such high current is mechanically and materially complex. means of solving the problem

[0009] The object of the present invention is achieved by a reactor that generates a chemical reaction having the features of an independent claim.

[0010] The present invention utilizes a measure in which each reaction tube is connected to only one phase and phase balance is established through multiple reaction tubes. Compared to an arrangement in which reaction tubes are connected to multiple phases, the heating length and resistance per phase are increased. This enables a higher power input at a constant current intensity by increasing the voltage (P = R*I 2, where P is power, R is resistance, and I is current intensity). Since each reaction tube has only one current supply through its respective supply element, the number of technically complex high-current supplies and the resulting power loss can be reduced.

[0011] A reactor that generates a chemical reaction within a process fluid using a multiphase alternating current to heat the process fluid comprises a reactor vessel formed by thermally insulating reactor walls and at least one or more multi-reactor tubes, wherein the alternating current has a number M of phases, and M is an integer greater than 1. Each group of multi-reactor tubes comprises M reaction tubes, and each reaction tube has an electrically heated heating zone extending between the first and second removal zones of the corresponding reaction tube and has a respective heating length. The heating zones are positioned within the reactor vessel over at least 95% of the heating length, and each has a feed zone in the area of ​​20% to 80% of the heating length of the heating zone. The ratio of "20% to 80%" indicates a location within the heating length, i.e., 0% indicates the location of the first (or second) removal zone, 50% indicates the middle of the heating zone, and 100% indicates the location of the second (or first) removal zone (i.e., does not imply a ratio).

[0012] In the supply zone connected to the power source via the supply element, one phase of the multiphase AC current is supplied to the heating zone in each case. That is, the AC voltage corresponding to each phase is applied. In the removal zone connected to the star bridge via the removal element, each phase of the AC is removed or discharged from the heating zone. The star bridge is used to balance the different phases of the AC current.

[0013] The fact that reaction tubes are electrically heatable or have an electrically heatable heating zone implies that the materials used in the reaction tubes, and particularly in the heating zone, are materials with electrical conductivity suitable for electric heating. Examples include heat-resistant steel alloys, particularly heat-resistant chrome-nickel steel alloys. Such steel alloys can also be used for power connections (through which electric current is conducted to the reactor vessel), namely feed elements and removal elements. For example, standard designations according to DIN EN 10027, Part 1, "Materials" such as 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, and GX55NiCrWZr33-30-04 Materials can be used.

[0014] The reactor wall comprises an area enclosed in all spatial directions by at least one reactor wall. Generally, the reactor wall consists of several individual walls joined together to enclose the area. Therefore, this could be referred to as a group of reactor walls, but the term "reactor wall" is used simply. The enclosed area and, thus, the reactor wall, may have a volumetric shape, but preferably have a cubic shape. The reactor wall may have closed structural elements (such as feedthroughs or observation windows), but may also have permanently open and / or closable openings (i.e., inlet for inert gas or outlet opening to a chimney track) for connection to other parts, preferably for air control within the reactor wall.

[0015] The reactor walls form the reactor vessel (which may also be called a reactor box); in other words, the reactor walls constitute the walls or walls of the reactor vessel. Therefore, the term "reactor walls" here does not refer to the tank for the process fluid. The area enclosed by the reactor walls is the interior of the reactor vessel. For the remainder of the description, the area within the reactor vessel (i.e., the interior of the reactor vessel) is also simply referred to as "inside the reactor walls." The expression "inside the reactor walls" therefore means within 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 walls reduce heat loss and protect the reactor vessel or the area around the reactor from heat. Therefore, the heating length must be located within a substantial portion of the area enclosed by the reactor walls; in other words, according to the present invention, it must correspond to at least 95%, preferably 98%, and further to 100% of the interior of the reactor vessel (i.e., the heating area within the area completely enclosed by the reactor walls). This arrangement is preferably symmetrical; that is, for heating areas that do not heat 100% of the area enclosed by the reactor walls, the heating areas located outside the reactor vessel are arranged symmetrically along the heating length. In particular, the removal area may be located outside the reactor walls.

[0017] In each case, the supply area is preferably arranged within a heating area extending from 30% to 70% of the heating length, more preferably within a heating area extending from 40% to 60% of the heating length, and even more preferably within a heating area extending from 45% to 55% of the heating length. This means symmetrically dividing the current from the supply area into the first and second removal areas.

[0018] The reactor further comprises electrically conductive supply elements, and each group is paired with M supply elements that are electrically conductively connected to the group's supply area. Here, different phases of the alternating current may be supplied to or can be supplied to other supply elements paired with the group. The supply elements pass through the reactor walls and, in principle, constitute a power supply or power connection. The reactor also comprises first and second electrically conductive elimination elements, and each group is paired with M first elimination elements and M second elimination elements that are electrically conductively connected to the group's first or second elimination area. The elimination elements serve to distribute the electric current supplied through the supply elements and the supply area. The supply elements serve to supply high current.

[0019] Electrically conductive connections between a supply element and a supply area or between a removal element and a removal area can be made through interlocking connections, crimping connections (e.g., sleeves), or integral connections (e.g., welded connections), and combinations thereof are also possible.

[0020] The reactor further comprises at least one electrically conductive first star bridge (forming bridge) and at least one electrically conductive second star bridge, and each group is paired with the first and second star bridges. For each group, the first elimination element paired with the group is electrically connected to the first star bridge paired with the group, and the second elimination element paired with the group is electrically connected to the second star bridge paired with the group. Potential balance between different phases is achieved through the star bridges.

[0021] Preferably, at least one first star bridge and at least one second star bridge are arranged outside the reactor vessel. An advantage of arranging the star bridges outside the reactor vessel (i.e., outside the reactor wall) is that a material with lower thermal resistance than that required when arranged inside the reactor vessel can be used. Accordingly, a material with high conductivity, such as copper, can be selected.

[0022] Therefore, the electrical resistance through the star bridge between different phases, that is, between different reaction tubes, is significantly smaller than the electrical resistance through the connection formed by the fluid supply pipe and fluid supply manifold connected to the reaction tube, or the fluid discharge pipe and fluid discharge manifold connected to the reaction tube. A fluid supply pipe refers to a pipe through which process fluid is supplied to each reaction tube, and likewise, a fluid discharge pipe refers to a pipe through which process fluid is discharged from each reaction tube. A fluid supply manifold consists of pipes connected to multiple supply pipes that distribute process fluid coming from other parts of the plant to multiple reaction tubes. A fluid discharge manifold consists of pipes connected to multiple discharge pipes to collect fluid coming from multiple reaction tubes for additional delivery to other parts of the plant after a chemical reaction. Fluid supply pipes together with the fluid supply manifold are referred to as a fluid supply pipe assembly or supply header, and fluid discharge pipes together with the fluid discharge manifold are referred to as a fluid discharge pipe assembly or discharge header. The fluid supply pipe assembly and the fluid discharge pipe assembly form electrical connections between the reaction tubes parallel to the first and second star bridges, respectively.

[0023] Preferably, the electrical resistance between two reaction tubes within a group spanning the first and / or second star bridge is to be within 50%, more preferably 25%, and even more preferably 10% of the electrical resistance formed circuitously in parallel with the fluid supply tube assembly and / or fluid discharge tube assembly.

[0024] This has the advantage of being able to substantially achieve potential balance through a star bridge, particularly to reduce situations that may occur due to a potential difference between the fluid supply pipe assembly and the fluid discharge pipe assembly (such as electric current flowing through other parts of the plant outside the reactor).

[0025] Preferably, the first and second removal zones are arranged inside the reactor vessel, and the first and second removal elements extend through the reactor wall in an extended form. More preferably, the heating zone is arranged entirely inside the reactor vessel. By doing so, heat loss can be reduced.

[0026] Preferably, when several groups are paired with at least one first star bridge, those several groups are paired with the same second star bridge.

[0027] Furthermore, for at least one of the groups, the first and second star bridges paired with this group are electrically connected to each other by bridge connecting means. By doing so, the potential difference between the star bridges can be balanced. This arrangement may also exist even when at least one group includes multiple groups.

[0028] The reactor preferably includes one or more alternating current sources, each alternating current source supplying an alternating current of phase M to an M-phase line. Here, each group is paired with one of the one or more alternating current sources, and for each group, the supply element paired with that group is connected to the phase line of the alternating current source paired with the group.

[0029] Preferably, at least one star point is formed in at least one of one or more alternating current sources, wherein for one of at least one group, the first and / or second star bridge paired with the group is connected to the star point of the alternating current source paired with the group through one or more neutral conductors. This allows for a specific change in current intensity between phases.

[0030] Preferably, one of the one or more alternating current sources is paired with several groups, and these several groups are paired with the same first star bridge and the same second star bridge.

[0031] Preferably, each heating tube region has several straight tube regions connected to one another through one or more U-bends, and more preferably, the number of tube regions is even. This allows the tube coils to be formed to enable a compact design of the reactor.

[0032] Preferably, the supply regions are each located in one of the U-bends. Since the U-bends are located outside the reactor wall and near the reactor wall, the high current supply formed by the supply element can be maintained over a relatively short distance.

[0033] Preferably, the removal elements are connected to an electrically insulated holding device for connection to a support structure, wherein the holding device is connected in a manner that is electrically insulated from the removal elements and / or is electrically insulated from itself. In particular, if the removal elements pass through the reactor wall, they may also perform a support function. The support structure may be, for example, part of a production facility where the reactor is installed.

[0034] Additionally, preferably, each reaction tube is provided with at least one support device for connecting to a support structure, the support device being connected to the reaction tube, wherein at least one support device is connected to the reaction tube in an electrically insulated manner and / or is electrically insulated itself, and more preferably is located in one of the U-bends.

[0035] Preferably, all feedthroughs passing through the reactor walls for the removal element, fluid discharge pipe, and fluid supply pipe are gas-sealed using suitable devices such as sealing bellows. These gas-sealing devices are designed to be electrically insulated to prevent electrical contact between the supplied components and the reactor walls. These devices may also be provided for supplying current (i.e., to the supply elements) and are used particularly when small thermal balance movements occur, for example, when the current supply is arranged at the top as shown in FIG. 2.

[0036] The phase shift between two different phases of alternating current is 2π*k / M in radians, where k is an integer in the range of 1 to M-1. In the case of a symmetric load, the phases cancel each other out at the star point or star bridge.

[0037] The chemical reaction may be a chemical reaction that proceeds at least partially in the range of 200°C to 1700°C, particularly in the range of 300°C to 1400°C or 400°C to 1100°C. The chemical reaction is preferably a chemical reaction that takes place at a temperature of at least 500°C or higher, more preferably at a temperature of at least 700°C or higher, and particularly a chemical reaction that takes part in the temperature range of 500°C or 700°C to 1100°C. Accordingly, the provided electrical voltage / current is suitable for providing appropriate heating power. The reactor and the power source are configured to perform the chemical reaction at these temperatures and provide the corresponding heating power. Preferably, the chemical reaction may be one of the following: steam pyrolysis, steam reforming, dry reforming (carbon dioxide reforming), propane dehydrogenation, or a hydrocarbon reaction that generally takes place at least partially at 500°C or higher.

[0038] The present invention is described primarily with respect to reaction tubes and reactors used for steam pyrolysis or steam reforming. However, the present invention may be used with other types of reactors. Generally, as mentioned, the reactor according to the present invention can be used to carry out all endothermic chemical reactions.

[0039] The present invention is described in detail below based on the drawings showing embodiments of the present invention. Brief explanation of the drawing

[0040] FIG. 1 shows a perspective view of a reactor connected to an alternating current source according to a preferred embodiment of the present invention. FIG. 2 shows a front view of a reactor according to another preferred embodiment of the present invention. FIG. 3 shows a front view of a reactor according to another preferred embodiment of the present invention. Specific details for implementing the invention

[0041] Elements that correspond structurally or functionally to one another in the drawings are indicated by the same or similar reference numerals and are not described repeatedly for clarity.

[0042] FIG. 1 shows an (alternative) perspective view of a reactor (2) connected to an alternating current source (10) according to a preferred embodiment of the present invention. The reactor (2) has a thermally insulated reactor wall (4) and several reaction tubes (6u, 6v, 6w). The outline of the reactor wall is indicated by a two-dot dashed line in the drawing, through which a process fluid is heated and flows, and chemical reactions occur within the reaction tubes. The reactor wall forms a reactor vessel as described above. The reaction tubes form a group. The number of reaction tubes (within a group) corresponds to the number of phases of the alternating current source, for example, three phases, but two or more other numbers are possible. Generally, several groups of reaction tubes may be provided, and the number of reaction tubes within each group corresponds to the number of phases. In this general case, one or more alternating current sources may be provided, and the phases of the alternating current sources may be connected to the reaction tubes of different groups. That is, an alternating current source supplies alternating current to one or more groups of reaction tubes, and said one or more groups are paired with an alternating current source that supplies alternating current.

[0043] Each of the reaction tubes (6u, 6v, 6w) has a heating zone (20) extending between the first removal zone (22) and the second removal zone (23). For clarity of the drawing, the drawing symbol is used here as well as in the following content to indicate one of several similar elements. The length of the reaction tube, i.e., the heating zone (20), between the first and second removal zones (22, 23) is called the heating length. The heating length is extended by winding the tube coil several times, which is formed by each of the reaction tubes. The heating zone (20) of each reaction tube is arranged within the reactor wall (4).

[0044] More generally, unlike in FIG. 1, the removal area (22, 23) may be located outside the reactor wall, and as described in FIG. 2, in this case, the heating area extends through the reactor wall (where the heating area located outside the reactor wall should be as small as possible to avoid heat loss), and the heating area must be located within the reactor wall for at least 95% of the heating length.

[0045] The reactor wall (4) forms a closed casing for the area of ​​the reactor (2) through which the heating zone, through which the process fluid is heated, passes, except for a supply through for supplying or discharging process gas and for supplying or discharging current. The supply and removal of the process fluid are carried out through a fluid supply pipe (26) or a fluid discharge pipe (27) connected to the reaction pipe, and each pipe is connected to a fluid supply manifold (28) or a fluid discharge manifold (29). Through this, the process fluid is transferred from another production facility part to the reaction pipe and, after the chemical reaction, is discharged from the reactor to the other production facility part. The fluid supply pipe (26) forms a so-called supply header (fluid supply assembly) together with the fluid supply manifold (28), and the fluid discharge pipe (27) forms a so-called discharge header (fluid discharge assembly) together with the fluid discharge manifold (29).

[0046] Each reaction tube (6u, 6v, 6w) or corresponding heating area (20) has a supply area (24) at a position approximately midway between the first and second removal areas (22, 23), generally between 20% and 80% of the heating length. Each supply area (24) is electrically connected to an electrically conductive supply element (32), which is then electrically connected to one phase or phase line U, V, W of an alternating current source (10). The supply element (32), which represents a current terminal, extends through the reactor wall (4) and, for example, has an elongated shape, with one end connected to the corresponding supply area (24) and the other end connected to one of the phase lines U, V, W. A supply element connected to a group of supply areas is paired with that group.

[0047] The alternating current source (10) preferably supplies alternating current in multiple phases along with a predetermined alternating voltage (here, three-phase alternating current). More generally, several M of other phases can also be considered. The phase shift between the phases is preferably selected so that the voltage and current cancel each other out at the star point. That is, the phase shift between any two phases can be expressed as 2π*k / M in radians or 360°*k / M in degrees, where k is an integer from 1 to M-1. In the case of three phases, it is therefore expressed as 2π / 3 or 4π / 3, corresponding to 120° or 240°, respectively. In this case, the phase difference between two consecutive phases is k=1, i.e., 2π / M.

[0048] The alternating current source (10) can be designed as an alternating current transformer, and in particular as a high-current transformer. Here, the primary side (e.g., coming from an overhead power supply network or a generator) supplying alternating current to the power source (10) is shown in the form of a shaded box representing the primary side transformer coil. The primary side power supply line is not shown in the drawing. The primary side alternating voltage can typically range from hundreds of volts to thousands of volts, and can be, for example, 400 V, 690 V, or 1.2 kV. To obtain an input voltage suitable for a high-current transformer, at least one additional transformer (not shown in the drawing; at least one of these transformers may be a regulating transformer capable of controlling the secondary side AC voltage or regulating the AC voltage within a constant voltage range) may be positioned between the primary side of the power source (10) and a possible overhead power supply network or generator. Instead of or in addition to the at least one intermediate transformer, the input voltage may be set by one or more thyristor power controllers.

[0049] On the secondary side, phase lines or phase terminals U, V, and W are provided, and phases of alternating current are provided therein. Phase lines U, V, and W receive electrical energy through a secondary side transformer coil not shown in detail (in the drawing, the phase lines are shown passing through the primary side transformer coil (12) to indicate that the phase lines interact electromagnetically with each other). For convenience, the secondary side alternating voltage may be located in a range of 300 V or less, for example, less than 150 V or less than 100 V, or even less than or equal to 50 V. The secondary side is electrically isolated from the primary side.

[0050] The phase lines U, V, and W are connected to any one of the alternating current sources (10), thereby forming a star point (14) of the alternating current source (10). It is preferable that the grounding of this star point (14) be absent. The star point (14) can optionally be connected to the neutral line N.

[0051] The first removal area (22) is electrically connected to the first removal element (34) which is electrically conductive, and these are electrically connected to each other by the first star bridge (36) which is electrically conductive. The second removal area (23) is electrically connected to the second removal element (35) which is electrically conductive, and these are electrically connected to each other by the second star bridge (37) which is electrically conductive. The removal elements connected to the removal areas of the group are paired with the corresponding group.

[0052] Preferably, the first and second removal elements (34, 35) extend through the reactor wall (4), and more preferably (as shown in FIG. 1), the first and second star bridges (36, 37) are located outside the reactor wall. If the removal area is outside the reactor wall, the removal elements do not extend through the reactor wall.

[0053] More preferably, a holding device (40) connected to a removal element (34, 35) is provided, and the holding device (40) is connected to the removal element (34, 35) in an electrically insulated manner and / or self-insulated manner. In this case, the removal element may have an elongated shape, and the removal end of the removal element is connected to the removal area and the opposite holding end is connected to the holding device. The holding device (40) is configured to be connectable to a support structure (not shown in the drawing) of a production facility in which a reactor is installed. Thus, the holding device is primarily used to hold or support the reactor tubes (and the elements connected to the tubes). Alternatively or in addition, a support device (not shown in the drawing) connected to a heating area (20) is provided, and this support device is connected to the heating area (20) in an electrically insulated manner and / or self-insulated manner and extends through the reactor wall to be connected to the support structure, thereby securing the reactor tubes by the support device.

[0054] Accordingly, alternating current is supplied to or introduced into the heating area (20) through the supply area (24), and the removal areas (22, 23) are removed from the heating area (20). Starting from the supply area (24) of the heating area (20), the electric current flows first to the first removal area (22) and then to the second removal area (23) according to their respective electrical resistances. Since different reaction tubes (6u, 6v, 6w) are supplied with different phases U, V, and W of the alternating current, potential balance is ideally achieved (i.e., with symmetrical loads) at two star bridges (36, 37) when there is a corresponding phase shift between the phases. From a circuit perspective, the star bridges form the consumer-side star points.

[0055] Optionally, one neutral wire N or multiple neutral wires are provided, through which the star bridge (36, 37) is electrically conductively connected to the alternating current source (10).

[0056] Preferably, at least one electrically conductive bridge connection (38) is provided, which is electrically conductive and connected to the first star bridge (36) and the second star bridge (37).

[0057] The reaction tubes (6u, 6v, 6w) or their heating zones (20) shown in FIG. 1 are designed as tube coils, that is, they form straight tube zones (42) connected to each other through lower U-bends (44) and upper U-bends (45). In the specific embodiment shown in the drawing, the supply zones (24) are provided at the lower U-bends, respectively. The first and second removal zones (22, 23) are positioned at the upper portion of the tube zone (42), and the tube zone (42) is located in an elbow zone that can overlap the fluid supply tube (22) and the fluid discharge tube (23), respectively. However, it is also possible to provide the removal zones and supply zones at other portions of the tube coil.

[0058] In the embodiment shown in the drawing, the length of the area between the supply area (24) and the first or second removal area (22, 23) includes three straight tube areas, and thus the length of the area is significantly longer than in the case of a pipeline (as in the prior art) connected to three phases, more precisely to one phase at each lower U-bend, and the straight tube areas are electrically conductive and connected at opposite ends of each straight tube area. The length of the reaction tube connected to one phase is about three times longer and has a significantly higher resistance. A significantly high heating output is generated for each phase and reaction tube at a constant current intensity, and in particular, less high current supply is required.

[0059] The terms "top" and "bottom" indicate orientation in the drawing, in other words, are used to distinguish the corresponding U-bends. The actual orientation of the tube coil (in relation to the Earth's gravitational field) may differ. For example, the tube coil may be positioned downwards (when the tube region is horizontal), and its arrangement may be reversed compared to what is shown (removal elements, star bridges, and supply / discharge headers at the bottom, and supply elements at the top).

[0060] In FIG. 1, each reaction tube (6u, 6v, 6w) or each heating zone (20) has six straight tube zones (42) according to the embodiment, that is, divided into three U-shaped zones connected to each other through an upper U-bend (45). Other numbers are possible, for example, two straight tube zones (one U-shaped zone), four straight tube zones (two U-shaped zones; see FIG. 2), eight straight tube zones (two U-shaped zones), etc. In principle, an odd number of straight tube zones is also possible (see FIG. 3).

[0061] In each heating area (20) of FIG. 1, the supply area (24) is located in the exact middle of the heating length between the first removal area (22) and the second removal area (23). Variation is possible here as well, that is, the length of the heating area (first heating area) between the first removal area (22) and the supply area (24) (first heating length) may differ from the length of the heating area (second heating area) between the supply area (24) and the second removal area (23) (second heating length). The electric current is distributed according to the electrical resistance of these two areas (first / second heating areas), and thus different heating outputs can be obtained in the two areas.

[0062] FIG. 1 shows only one group consisting of several (e.g., three) reaction tubes. Generally, the reactor may include multiple such groups, and one or more alternating current sources are provided to each, that is, one or more groups are paired with the same alternating current source. Multiple first star bridges and multiple second star bridges may be provided, and one first / second star bridge may be connected to a removal element paired with another group. That is, these different groups are paired with the same first / second star bridge, preferably, the group paired with the same first star bridge is also paired with the same second star bridge. Preferably, when multiple groups are paired with the same alternating current source, these multiple groups must be paired with the same first star bridge and the same second star bridge.

[0063] FIG. 2 shows a front view of a reactor (52) according to another embodiment of the present invention. Since this drawing is intended to explain different designs of the reaction tube or tube coil and corresponding connection options for power supply, as with FIG. 3, only one reaction tube and its corresponding connection are shown. In principle, other reaction tubes (corresponding to the number of phases of the alternating current source) arranged perpendicularly to the drawing plane at a certain distance from the reaction tube shown in the drawing (transposed in parallel) are designed in the same way as shown in the drawing, the difference being that their supply areas are connected to different phases. Below, details or characteristics of the elements are not repeated except as in FIG. 1, and the description of FIG. 1 applies here as well.

[0064] The reactor (52) has a reactor wall (54) and a reaction tube (positioned perpendicular to the drawing plane), and in the front view, only one reaction tube (56u) is shown as a representative example. Each reaction tube (56u) has a heating area (20) having a heating length that extends between the corresponding first removal area (22) connected to the first removal element (34) and the corresponding second removal area (23) connected to the second removal element (35). The first removal element (34) is connected by a first star bridge (36) that extends perpendicular to the drawing plane, and the second removal element (35) is also connected by a second star bridge (37) that extends perpendicular to the drawing plane.

[0065] Each reaction tube (56u) or each heating zone is composed of straight tube zones (42) connected to each other by a lower U-bend (44) and an upper U-bend (45), forming a tube coil composed of four straight tube zones (two U-shaped zones). Similar arrangements having a different number of tube zones are also possible, for example, eight or twelve straight tube zones (four or six U-shaped zones), etc.

[0066] In contrast to FIG. 1, the supply area (24) is located in the upper U-bend (45) rather than the lower U-bend in this case. That is, it is once again located in the middle of the heating area. In other words, the removal area (22, 23) and the supply area (24) are located on the same side (top) of the reactor. The supply area (24) of the reaction tube (56u) visible here is connected to the phase line U of the alternating current source (not shown in detail). Thus, the supply area of ​​the other unseen reaction tube is connected to the other phase line of the alternating current source. Potential balancing between the other phases is again achieved through the star bridge (36, 37), which causes the star bridge to form a consumer-side star point in the circuit.

[0067] Regardless of the shape of the tube coil, in the embodiment of FIG. 2, the first and second removal areas (22, 23) are located outside the reactor wall (54). Of course, the configuration of FIG. 1, in which the removal area is located inside the reactor wall, is also possible.

[0068] Once again, one or more neutral conductors may be provided to connect the star bridges to the star points of an alternating current source and to the first star bridge (36) and the second star bridge (37), which are electrically conductive bridge connections. Likewise, a holding device (40) and / or a support device may be provided. These elements are mostly not shown in FIG. 2.

[0069] FIG. 3 shows a front view of a reactor (62) according to a more preferred embodiment of the present invention. Since the drawing is intended to explain different designs of the reaction tube or tube coil and corresponding connection options for power supply, as in FIG. 2, only one reaction tube and its corresponding connection are shown. In principle, other reaction tubes (corresponding to the number of phases of the alternating current source) arranged perpendicularly to the drawing plane at a certain distance from the reaction tube shown in the drawing (transposed in parallel) are designed in the same way as shown in the drawing, the difference being that their supply areas are connected to different phases. Below, details or characteristics of the elements are not repeated except as in FIG. 1, and the description of FIG. 1 applies here as well.

[0070] The reactor (62) also has a reactor wall (64) and a reaction tube (arranged perpendicular to the drawing plane), and in the front view of the embodiment, only one reaction tube (66u) is shown as a representative example. Each reaction tube (66u) has a heating area (20) having a heating length that extends between the corresponding first removal area (22) connected to the first removal element (34) and the corresponding second removal area (23) connected to the second removal element (35). The first removal element (34) is connected by a first star bridge (36) that extends perpendicular to the drawing plane, and the second removal element (35) is likewise connected by a second star bridge (37) that extends perpendicular to the drawing plane.

[0071] Each reaction tube (56u) or heating zone is composed of straight tube zones (42) connected to each other via a lower U-bend (44) and an upper U-bend (45) to form a tube coil. In contrast to the previous embodiment, an odd number of straight tube zones (42) are provided (here, for example, 5, other odd numbers are also possible). On the other hand, this results in the first removal zone (22) (and the corresponding first removal element (34)) being located at the top, and the second removal zone (23) (and the corresponding second removal element (35)) being located at the bottom. The terminology for "bottom" / "top" is described above.

[0072] Meanwhile, the supply area (23) arranged within the U-bend (e.g., located in the upper U-bend (45), but likewise positioned in the lower U-bend (44)) is not located in the middle of the heating area (20). That is, it is not at 50% of the heating length. The length of the area between the supply area (23) and the first removal area (22) is slightly shorter than the length of the area between the supply area (23) and the second removal area (24). In principle, it is possible to place the supply area in a straight tube area (in all embodiments), but it is preferable to place it within the U-bend. This is because if the supply area is placed in a straight tube area, the length of the supply element that must move a current of high current intensity and the corresponding resistance can be kept relatively low, and consequently, a correspondingly high power loss occurs.

[0073] In the embodiment of FIG. 3, the removal area is located inside the reactor wall (54), so that the removal element extends through the reactor wall. However, an embodiment in which the removal area is placed outside the reactor wall is also clearly possible.

[0074] Again, one or more neutral conductors (not shown in FIG. 3) connecting the star bridge to the star point of the alternating current source may also be provided. Likewise, a holding device (40) and / or a support device (not shown in the drawing) may also be provided.

Claims

Claim 1 In a reactor (2; 52; 62) that performs a chemical reaction of a process fluid using a multiphase alternating current to heat the process fluid, wherein the number of phases of the multiphase alternating current is M, where M is an integer greater than 1 and M is the same in all cases below, the reactor vessel formed by a thermally insulating reactor wall (4; 54; 64); at least one group composed of a plurality of reaction tubes (6u, 6v, 6w; 56; 66) - each group comprises M reaction tubes, each said reaction tube has an electrically heatable heating area (20) extending between the first and second removal areas (22, 23) of the said reaction tube for each heating length, said heating area is positioned within the reactor vessel for at least 95% of said heating length and each said heating area has a supply area (24) within an area extending from 20% to 80% of said heating length -; an electrically conductive supply element (32) - each group M supply elements are paired with electrically conductively connected to the supply area of ​​the above group, and other phases of the alternating current may be supplied to or can be supplied to other supply elements paired with one group - ; first and second removal elements (34, 35) having electrical conductivity - each group is paired with M first removal elements and M second removal elements that are electrically conductively connected to the first removal area or the second removal area of ​​the above group - ;A reactor for performing a chemical reaction of a process fluid comprising: a first star bridge (36) having at least one electrically conductive element and a second star bridge (37) having at least one electrically conductive element; wherein each group is paired with the first and second star bridges, and for each group, the first removal element paired with the group is electrically conductively connected to the first star bridge paired with the group, and the second removal element paired with the group is electrically conductively connected to the second star bridge paired with the group.; Claim 2 A reactor for performing a chemical reaction of a process fluid, characterized in that, in claim 1, at least one first and at least one second star bridge (36, 37) are arranged outside the reactor vessel. Claim 3 A reactor for performing a chemical reaction of a process fluid, characterized in that, in claim 2, the first and second removal zones (22, 23) are arranged inside the reactor vessel; the first and second removal elements (34, 35) have an elongated shape and extend through the reactor wall; and the heating zone (20) is completely arranged inside the reactor vessel. Claim 4 A reactor for performing a chemical reaction of a process fluid according to claim 1, characterized in that, when a plurality of groups are paired with at least one of the first star bridges, the groups are also paired with the same second star bridge. Claim 5 A reactor for performing a chemical reaction of a process fluid according to claim 1, characterized in that, for any one of the at least one group, the first and second star bridges (36, 37) paired with the group are electrically conductive and connected to each other by means of a bridge connection (38). Claim 6 A reactor for performing a chemical reaction of a process fluid according to claim 1, comprising one or more alternating current sources (10); each of the alternating current sources supplies alternating current to M phase lines (U, V, W) in M ​​phases; each of the groups is paired with one of the one or more alternating current sources; and for each of the groups, a supply element paired with the group is connected to the phase line of the alternating current source paired with the group. Claim 7 A reactor for performing a chemical reaction of a process fluid, characterized in that, in claim 6, at least one star point (14) is formed within at least one of one or more alternating current sources; and for any one of at least one group, the first and / or second star bridge paired with the group is connected to the star point of the alternating current source paired with the group through one or more neutral conductors (N). Claim 8 A reactor for carrying out a chemical reaction of a process fluid, characterized in that, in claim 6 or 7, one or more alternating current sources are paired with a plurality of groups; and said plurality of groups are paired with the same first star bridge and the same second star bridge. Claim 9 A reactor for performing a chemical reaction of a process fluid, characterized in that, in claim 1, each heating region has a plurality of straight tube regions (42) connected to one another by one or more U-bends (44, 45). Claim 10 A reactor for performing a chemical reaction of a process fluid, characterized in that, in claim 9, the supply area is located in each of the U-bends. Claim 11 delete Claim 12 delete Claim 13 delete Claim 14 delete

Images