Apparatus for carrying out chemical reactions in process fluids in a production system

Abstract

Provided is a device for carrying out a chemical reaction in a process fluid in a production system having at least one ground connection to ground. The device comprises a reactor comprising one or more reaction tubes which are introduced into and led out of the reactor via at least one feed section and at least one discharge section, respectively, and have a number of electrically heatable tube sections which are connected to one another in a current output region by means of an electrically conductive star bridge, and at least one power source which is configured to supply a multiphase alternating current having N phases at a predetermined voltage to N phase lines, wherein N is an integer greater than or equal to 2, and wherein, for each two phases, the phase shift between the two phases is 2π·k / N, wherein k is an integer in the range from 1 to N−1 in each case. A number N of power connections is provided for each of the at least one power source, each of which is connected to at least one of the tube sections in a current input region, wherein each of the power connections is connected to one of the phase lines of the power source, wherein, in the at least one power source, a star point is formed at which the phase lines of the power source are connected, wherein the star point is not connected to the ground connection.

Description

TECHNICAL FIELD

[0001] The invention relates to a device for carrying out chemical reactions in a process fluid in a production system; in particular, the invention relates to grounding of the device. BACKGROUND

[0002] Reactors are used in a series of processes in the chemical industry, in which one or more reactants are guided through a heated reaction tube and converted there, catalytically or non-catalytically. The heating serves, inter alia, to overcome the requirement of activation energy for the chemical reaction to take place. After overcoming the requirement of activation energy, the reaction can take place overall endothermically or exothermically. The invention relates in particular to strongly endothermic reactions.

[0003] Examples of these processes are steam cracking, different reforming processes, in particular steam reforming, dry reforming (carbon dioxide reforming), mixed reforming processes, processes for dehydrogenation of alkanes, etc. In steam cracking, the reaction tube is guided through the reactor in the form of a tube loop with at least one U-bend in the reactor, while in steam reforming, typically, a tube is used which extends through the reactor without a U-bend.

[0004] The invention is suitable for all these processes and embodiments of the reaction tube. By way of illustration only, reference is made to the articles "Ethylene", "Gas Production" and "Propenes" in Ullmann's Encyclopedia of Industrial Chemistry, for example the publication of 15 April 2009, DOI: 10.1002 / 14356007.a10_045.pub2, the publication of 15 December 2006, DOI: 10.1002 / 14356007.a12_169.pub2 and the publication of 15 June 2000, DOI: 10.1002 / 14356007.a22_211.

[0005] Conventionally, the reaction tube of the corresponding reactor is heated by using a burner. The reaction tube is guided through a combustion chamber in which the burner is also arranged.

[0006] However, the demand for synthesis gas and hydrogen produced without or with reduced local carbon dioxide emissions is currently increasing, as described, for example, in DE 10 2015 004 121 A1 (also EP 3 075 704 A1). However, processes using combustion reactors cannot meet this demand based on the combustion of typically fossil energy carriers. Other processes are rejected, for example, due to high costs. The same applies to the provision of olefins and / or other hydrocarbons by steam cracking or dehydrogenation of alkanes. In these cases, too, there is a desire for processes that emit at least less carbon dioxide on site.

[0007] Against this background, the cited DE 10 2015 004 121 A1 proposes electrical heating of the reactor for steam reforming in addition to combustion. Here, one or more voltage sources are used, which provide a three-phase alternating voltage on three external conductors. Each external conductor is connected with a reaction tube. A star connection is formed, in which the star point is realized by a collector, into which the lines open and the reaction tubes are in electrically conductive connection with the collector. In this way, the collector ideally remains free of electrical potential. WO 2015 / 197181 A1 likewise discloses a reactor, the reaction tubes of which are arranged in a star point connection.

[0008] The process medium is fed to the reactor or discharged from the reactor via a feed section and a discharge section as sections of the reaction tube. The feed section and the discharge section as sections of the reaction tube are connected with tube sections (tube sections) for heating by means of an electrical current. Due to the process medium used and the high process temperatures, the use of electrically insulating materials (for example, plastics or ceramics) is not possible or is possible only with difficulty for the feed section and the discharge section, so that the problem arises that an electrical current can be conducted via these sections from outside the reactor into the production system using the reactor and can cause damage to other components of the production system and harm to humans, in particular since the above-mentioned ideal case of an electrically potential-free collector is not always achievable. SUMMARY

[0009] This object is achieved by the device having the features of independent claim 1; the dependent claims relate to preferred embodiments of the invention.

[0010] According to the invention, the star point of the electrical power source is not earthed. Thus, if there is a potential difference between the star point and the feed section or the discharge section, this cannot result in a current flow from the feed section or the discharge section via the production system to earth and from there to the star point (which is dangerous for the production system (electrical safety / explosion protection) or damaging (corrosion / equipment defects)).

[0011] An apparatus for carrying out a chemical reaction in a process fluid in a production system having at least one ground connection for connecting to ground for grounding production system components comprises a reactor and at least one power source. The reactor has one or more reaction tubes which are introduced into and led out of the reactor via at least one feed section and at least one discharge section, respectively, and has several electrically heatable tube sections which are connected to one another in a current output region by means of an electrically conductive star bridge. In particular, the process fluid is fed to the reactor or the reaction tube via the feed section and is discharged from the reactor or the reaction tube via the discharge section. The at least one power source is configured to supply a multiphase alternating current having N phases with a predetermined voltage to N phase lines, wherein N is an integer greater than or equal to 2, and wherein, for each two phases, the phase shift between the two phases is 2pik / N, wherein k is an integer in the range from 1 to N-1 in each case; a number N of power connection heads is provided for each of the at least one power source, each of which is connected to at least one of the tube sections in a current input region, wherein each of the power connection heads is connected to one of the phase lines of the power source. A star point is formed in the at least one power source, at which the phase lines of the power source are connected, wherein the star point is not connected to a ground connection (i.e. the star point is not grounded).

[0012] The chemical reaction can be a chemical reaction which is carried out at least partially at a temperature in the range from 200°C to 1700°C, in particular from 300°C to 1400°C or from 400°C to 1100°C. The chemical reaction is preferably a reaction which is carried out at least partially at a temperature of at least 500°C, more preferably at a temperature of at least 700°C, in particular at least partially in a temperature range from 500°C or 700°C to 1100°C. The supplied voltage / current is correspondingly adapted to provide the corresponding heating power. The reactor and the power source are likewise configured to carry out the chemical reaction and to provide the corresponding heating power at these temperatures. Preferably, the chemical reaction is one of the following: steam cracking, steam reforming, dry reforming (carbon dioxide reforming), propane dehydrogenation, reactions with hydrocarbons in general which are carried out at least partially above 500°C.

[0013] In this case, the production system is to be understood as meaning, in particular, an industrial system in which the process medium or process fluid is subjected to a chemical reaction. For example, the system can be arranged in a production building. In addition to the device according to the application for carrying out a chemical reaction, the production system usually also comprises further system components (or other system components, i.e. system components other than the device), which are system components in which the process fluid is subjected to a pre-treatment and from which the process fluid is fed to the reactor or reaction tube (i.e. is directed into the reactor or reaction tube) via the feed section, and in which the process fluid is subjected to a post-treatment and from which the process fluid is discharged from the reactor or reaction tube (i.e. is directed away from the reactor or reaction tube) via the discharge section, etc.

[0014] The production system comprises a grounding connection, which acts as a grounding component of the system (i.e. the device according to the application and the further system components) by connecting the components of the system to the grounding connection via electrical lines.

[0015] Preferably, N = 3, i.e. a three-phase alternating current, the so-called three-phase current, is used. The consecutive phases are located at an offset of 2π / 3 (corresponding to 120°) in each case. The use of a three-phase alternating current enables, in particular, a connection to a public power supply network.

[0016] Preferably, a neutral conductor is provided, which connects the star bridge to the non-grounded star point of the power source. A possible potential difference between the star bridge and the star point of the power source, which can arise due to an asymmetric load on the phases, can thus be partially compensated for (taking into account the resistance of the neutral conductor).

[0017] Preferably, the star bridge is not connected to the grounding connection. Thus, hazardous (electrical safety / explosion protection) or harmful (corrosion / equipment defects) currents cannot also occur via the earth, the grounding connection of the further system components and the feed or discharge section, which is in electrically conductive connection with the further system components, from the location of the star bridge to which the line of the grounding connection is attached to the other system components.

[0018] Furthermore, a main grounding rail is preferably provided, and the feed section and the discharge section are in electrically conductive connection with this main grounding rail. This is expedient, since a potential equalization between the feed section and the discharge section can take place via the main grounding rail, and a possible current flow via the further system components is thus at least reduced. In particular, a main grounding rail is provided in the production system, which is in electrically conductive connection with the earth, wherein one or more of the grounding connections are provided on the main grounding rail (these grounding connections are thus connected to the earth via the main grounding rail).

[0019] Preferably, the feed section and the discharge section are arranged spatially adjacent to each other and are conductively connected to each other by a (electrically conductive) connection element. Due to the spatial extent of the reactor and especially of the star bridge, which in each case can be several meters, potential differences can occur on different sides of the reactor or star bridge. By arranging the feed section and the discharge section adjacent to each other, these potential differences can be prevented from manifesting as different potentials of the feed section and the discharge section, which can lead to an undesired current flow, for example, from the feed section via the production system to the discharge section. The additional conductive connection via the connection element enables a direct potential equalization between the feed section and the discharge section without an indirect potential equalization by means of a current flow via the production system.

[0020] It is to be noted here that when referring to a potential equalization here, this potential equalization can of course not be perfect due to the non-zero electrical resistance of the electrical conductors. In terms of the electrical circuit, the elements via which the potential equalization takes place, for example the connection element, form resistances, as do the other system components and the earth. However, the resistances of the elements via which the potential equalization takes place are very low compared to the current paths via the other system components, so that essentially no current flow takes place via the latter.

[0021] More preferably, the distance between the adjacent feed section and the discharge section is less than one tenth of the size of the star bridge. Possible sizes are preferably as follows: the distance between the adjacent feed section and the discharge section is less than 10 cm, preferably less than 5 cm. Due to these small dimensions, there can generally be only a relatively small potential difference (compared to the maximum potential difference over the entire extension of the star bridge). The size of the star bridge can for example be the diameter of the smallest sphere which completely encloses the star bridge, i.e. the sphere with the smallest diameter.

[0022] The connection element is preferably connected to the ground connection via a ground connection line. Especially when the star bridge is not grounded, the conductive connection of the connection element to the ground connection results in terms of the electrical circuit from the other system components in a "single-point" grounding of the device. In fact, the device is grounded exactly at a single location, at which the other system components are conductively connected to the device via the feed section and the discharge section. Neither the power source nor the consumer (reactor, reaction tube) is (directly) grounded. That is, from the perspective of the other system components, the device according to the application is connected in terms of the electrical circuit (in the sense of the electrical circuit) only at this one point of grounding; there are no other direct or indirect electrical connections. The "point" here is of course not to be understood in the sense of a zero-dimensional geometric point, but rather in the electrical engineering sense of an electrically connected point of (as small a geometric extension as possible).

[0023] Preferably, the electrically conductive connection element is produced integrally, in particular as a cast component, wherein the connection element is more preferably produced integrally with the tube inlet section and the tube outlet section. If the connection element is produced as a cast component, one end of the ground connection line is preferably cast into the cast component. These measures advantageously result in low resistances between the individual elements, wherein in particular no contact resistances occur between the elements.

[0024] Further advantages and embodiments of the application are presented from the description and the drawings.

[0025] The application is schematically represented in the drawings using exemplary embodiments and is described below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 A device according to a preferred embodiment of the application is shown;

[0027] Figure 2 A device according to another preferred embodiment of the application is shown;

[0028] Figure 3 A cross-sectional view of a connection element that can be used in embodiments of Figure 2 the application is shown.

[0029] In the drawings, elements corresponding to each other in structure or function are denoted by the same or similar reference signs, and the explanation is not repeated for the sake of clarity. DETAILED DESCRIPTION

[0030] Figure 1 A device 100 according to a preferred embodiment of the application is shown installed in a production system 2. The device 100 comprises a reactor 110 for carrying out a chemical reaction in a reaction medium or process fluid flowing through an electrically heated reaction tube 12 and an electric power source 30 providing the electric current required for the electric heating at a suitable voltage.

[0031] For the sake of clarity, the reference signs are provided only once or twice for elements that occur several times in the drawings.

[0032] One or more earthing points or earthing connections 4 are provided in the production system 2 which are in electrically conductive connection with the earth 5. The components of the production system (the device according to the application, other system components) are earthed via these earthing connections. Typically, the production system has a concrete base plate on which the components of the system are mounted. The earthing connections are therefore provided on this base plate, wherein electric conductors (for example, electrically conductive metal strips or cables) are guided from the earthing connections through the base plate into the earth or even into water (river water). One or more of these earthing connections can be connected together via an earthing rail (i.e. a so-called main earthing rail (not shown)) which is in connection with the earth, so that, in a manner of speaking, indirect earthing takes place via the main earthing rail. Furthermore, the production system 2 has, in addition to the reactor 110, other system components 6 (only symbolically shown by a rectangle) in which, inter alia, pre- and post-treatment of the process fluid takes place. The other system components are connected to the earthing connections via earthing lines 7.

[0033] The reactor 110 comprises one or more reaction tubes 12 (only one is shown here) in which chemical reactions of the process fluid take place by means of heating. The reactor 110 preferably has an insulation layer, for example in the form of an insulated reactor wall. The reaction tube 12 shown has the shape of a tube loop, which is guided from a feed section 152 through which the process fluid is fed to the reaction tube or reactor, via tube sections 14 and tube bends 16, 17 which together form the tube loop, to a discharge section 154 through which the process fluid is discharged (guided away) from the reaction tube or reactor. The feed section 152 and the discharge section 154 therefore electrically conductively connect the reactor 110 with the other system components 6 in which, inter alia, the process fluid is provided and pumped through the reactor tube or further treated after the chemical reaction. The feed section 152 and the discharge section 154 extend substantially through the reactor wall if provided.

[0034] The material for the reaction tube is a material having an electrical conductivity suitable for the electric heating of the reaction tube (for example, a heat-resistant steel alloy, in particular a heat-resistant chromium-nickel steel alloy). The feed section and the discharge section as components of the reaction tube are thus electrically conductive. These steel alloys can likewise be used for the power connection (via which the current is conducted into the reactor vessel) and the connecting bridge (which is at least partially arranged in the reactor vessel). For example, the materials 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 with the standard designation according to DIN EN 10027, Part 1, "Materials" can be used.

[0035] In the case of a plurality of reaction tubes in the form of, for example, a package comprising a plurality of reaction tubes or tube loops arranged parallel to one another and at a distance from one another perpendicular to the drawing plane, a separate feed section and a separate discharge section can be provided for each reaction tube. It is, however, preferred that at least some, in particular even all, of the plurality of reaction tubes are introduced into the reactor via a common feed section and / or are led out of the reactor via a common discharge section. Such (or all) reaction tubes are then connected in the reactor via a distributor arrangement to the common feed section and / or to the common discharge section. In the case of the above-described arrangement in the form of a package, the tubes of the distributor arrangement accordingly extend perpendicular to the drawing plane. These distributor arrangements are also referred to as headers.

[0036] In addition to tube loops, the reaction tubes can of course also be guided through the reactor by another form, for example, each reaction tube can have a U-shape in the reactor, or only straight reaction tubes are provided, wherein in these tubes in any case a connection to one or more feed sections and one or more discharge sections is made via a distributor arrangement. Different power connections (and accordingly different phase lines) are then connected to different reaction tubes.

[0037] The electrical heating of the reactor tube 12 takes place via the tube sections 14 through which an electric current, more precisely an alternating current, flows, wherein the electric current is fed into the tube sections 14 in the current input regions and released from the tube sections 14 in the current output regions. To this end, the tube sections 14 are in electrically conductive connection with the power connection heads 20 in the current input regions and with the (electrically conductive) star bridge 22 in the current output regions. Each of the power connection heads 20 is connected with one or more of the tube sections 14 (obviously, a single tube section should not be connected with multiple power connection heads at the same time). The electric current is provided as an alternating current, different power connection heads being connected with different phases, see the further description of the power source 30 below.

[0038] The current input regions are formed in the figure by the lower tube bends 16, which are in electrically conductive connection with the corresponding power connection heads 20 (for example, busbars leading into the reactor), i.e. in electrically conductive contact with them (from the power connection heads, the electric current is thus fed indirectly into the tube sections via the lower tube bends). The current output regions are formed in the figure by the upper tube bends 17, which are in electrically conductive connection with the star bridge 22 (the electric current is thus released indirectly via the upper tube bends). Lower / upper in this respect only relate to the arrangement in the figure, the actual arrangement can be different. In deviation therefrom, the power connection heads and / or the star bridge can also be in direct electrically conductive connection with the tube sections, for example via corresponding sleeves surrounding the tube sections.

[0039] Furthermore, the reactor 110 or the reactor tube 12 is supported by a support device (not further shown in detail) of the production system, for example by means of a suspension 18. The suspension 18 is connected here via an electric (and thermal) insulation with the star bridge 22, which in turn is connected with the reactor tube 12 and thus supports the latter. Different support arrangements are conceivable here as well, wherein in each case a suitable electrical insulation and thermal insulation must be ensured.

[0040] The power source 30 is designed as an alternating current power source, which provides a multi-phase (here, three-phase) alternating current at a predetermined alternating voltage. More generally, also a different number N of phases is conceivable. The phase shift between the phases is chosen such that the voltages or currents cancel each other out at the star point, i.e. the phase shift between two arbitrary phases can be expressed as an arc measure of 2π·k / N or in degrees of 360°·k / N, wherein k is an integer in the range from 1 to N-1. In the case of three phases, thus 2π / 3 or 4π / 3, corresponding to 120° or 240°. The phase difference between two consecutive phases is obtained in the case of k = 1 (i.e. 2π / N).

[0041] The power source 30 is designed as an AC transformer, in particular a high current transformer. A primary side (i.e. an AC current source powering the power source 30) is only shown here in the form of a shaded box representing a primary side transformer coil 32, e.g. from a public power supply network or a generator. The primary side supply lines are not shown in the figure. The primary side AC voltage can typically be in the range of several hundred to several thousand volts (e.g. 400 V, 690 V or 1.2 kV). Between the primary side of the power source 30 and possibly the public power supply network or the generator, at least one further transformer (not shown) can be inserted (possibly at least one regulating transformer) to obtain a suitable input voltage for the high current transformer. Instead of or in addition to such an inserted at least one transformer, the input voltage can also be set by means of one or more thyristor power controllers.

[0042] On the secondary side, phase lines U, V, W are provided on which phases of an AC current are provided. The phase lines U, V, W are supplied with electrical energy via secondary side transformer coils which are not shown in detail (only the phase line extensions through the primary side transformer coil 32 are shown to indicate that they electromagnetically interact with each other). The secondary side AC voltage can conveniently be in the range up to 300 V (e.g. less than 150 V or less than 100 V, even less than or equal to 50 V). The secondary side is electrically isolated from the primary side.

[0043] The phase lines U, V, W are connected to each other in the power source 30 so that a star point 34 of the power source 30 is formed. This star point 34 is omitted from grounding. That is, the star point 34 of the power source is electrically insulated from the ground connection 4 of the production system 2; thus there is no connection to the ground connection via an electrical conductor (and no other connection to earth is provided via an electrical conductor).

[0044] The phase lines U, V, W are connected with the associated different power connection 20. The multi-phase AC current is thus fed into the tube section connected with the power connection, wherein the different phases of the AC current are fed into the tube section connected with the different phase line via the respective power connection. For this multi-phase AC current flowing through the tube section 14, the star bridge 22 forms a star point (star point of the reactor) in terms of the circuit so that, ideally in the case of a symmetrical load, the currents or voltages cancel each other out.

[0045] Furthermore, a neutral conductor N is provided which electrically conducts the two star points to each other, i.e. it is connected on the one hand with the star point 34 of the power source 30 and on the other hand with the star bridge 22 (star point of the reactor).

[0046] Although only one power source is shown, in general a plurality of power sources can also be provided, in particular if a plurality of reactor tubes is provided. Different power sources can then be connected with e.g. different reactor tubes or different subsets of reactor tubes.

[0047] Due to the fact that the different phases of the power source are typically not loaded asymmetrically (for example due to different temperatures and different resistances of the tube sections to which the different phase lines are connected), a potential difference can occur between the star bridge 22 and the star point 34 of the power source. This potential difference is partly compensated by the neutral conductor N; however, since the neutral conductor has a finite (i.e. non-zero) resistance, a certain potential difference usually remains.

[0048] In terms of the electrical circuit, the reaction tube is electrically conductively connected with further or other system components 6 of the production system 2 via the feed section 152 and the discharge section 154 with a certain resistance. The other system components 6 are in turn connected with the grounding connection 4 and thus with the earth 5 via the grounding line 7. However, since the star point 34 of the power source is not grounded (and electrically isolated from the primary side), a current flow from the star bridge 22 via the other system components 6 to the earth 5 and from there to the star point 34 of the power source is not possible. That is, a current flow through the other system components 6, which can lead to damage or danger there, which can be caused by the potential difference, can be avoided or at least reduced.

[0049] Figure 2 A device 200 according to a further embodiment of the application is shown, again together with the production system 2 in which the device is installed. In the basic components, Figure 2 the device 200 shown is similar to Figure 1 the device 100 shown. For the sake of simplicity, the description of the elements already described (in particular the electrical heating of the power source and the tube sections) is not repeated, but reference is made in this regard to Figure 1 ; the same reference signs as in Figure 1 are used for these elements. The device 200 comprises a reactor 210 and a power source 30.

[0050] In the reactor 210 of the device 200, the feed section 252 and the discharge section 254 are arranged spatially close to each other and electrically conductively connected to each other (in contrast to the device 100 of Figure 1 ). As a result, the difference between the electrical potential at the feed section 252 and the electrical potential at the discharge section 254 is reduced, which difference can lead to a current in the other system components 6, which flows via these other system components between the feed section 252 and the discharge section 254. These different potentials can exist between different regions of the star bridge (which material has a non-vanishing resistance due to its spatial extension (which can be for example several meters; in this sense, the star bridge does not form a star "point")), and are transmitted to the feed section and the discharge section when these are not arranged spatially close to each other.

[0051] "spatially close" can be specified in the sense of an extension (e.g. average size or maximum size) of the spatial extension relative to the star bridge; for example, the distance between adjacent feed section and discharge section should at most be one tenth of the spatial extension of the star bridge. Likewise, an absolute distance can be specified, for example, the distance between adjacent feed section and discharge section should be less than 10 cm, preferably less than 5 cm.

[0052] In Figure 2 , the feed section 252 and the discharge section 254 are connected to each other by means of an electrically conductive connection element 256, such that any potential difference between the feed section and the discharge section is compensated for, the risk of current flow through other system components 6 is thus reduced. This connection element 256 is connected via a ground line 257 with a ground connection of the production system 2. This ground represents the only ground via the connection element 256 and thus a single-point ground as far as the electrical circuit is concerned, since no further ground of the reactor is provided, in particular the star point 34 of the power supply is not grounded.

[0053] In Figure 2 , the connection element 256 is essentially located at the height of the reactor wall or on it, but it is also possible to arrange the connection element outside the reactor (e.g. outside the possible reactor wall) or inside the reactor.

[0054] In Figure 3 , a preferred embodiment of the connection element 256 is shown. According to this embodiment, the connection element 256 is integrally made (in particular cast) with the feed section 252 and the discharge section 254, wherein the connection is electrically conductively connected with the ground connection line 257. More preferably, as shown, one end of the ground connection line (e.g. an electrically conductive metal strip) is cast into the connection element. Alternatively, the feed section and the discharge section can be guided as tube sections through openings 262, 264 in the connection element 256; for this, for example, the connection element can first be heated and (during subsequent cooling) shrink onto the feed section and the discharge section to achieve good electrical contact. It is noted that, as shown in Figure 3 , the geometric arrangement of the elements is only for illustrative purposes and not limiting the scope of protection; i.e. in actual embodiments, the geometric arrangement can differ from the one shown in Figure 3 . Likewise, the shown relative sizes of the individual elements are only as an example and can generally differ in actual embodiments.

Claims

1. An apparatus (100, 200) for carrying out a chemical reaction in a process fluid in a production system (2), the production system (2) having at least one ground connection (4) to the earth for grounding production system components, the apparatus (100, 200) comprising: a reactor (110, 210) comprising one or more reaction tubes (12) introduced into and led out of the reactor via at least one feed section (152, 252) and at least one discharge section (154, 254), respectively, and having a number of electrically heatable tube segments (14) connected to each other in a current output region by an electrically conductive star bridge (22); and at least one power source (30) configured to provide a multiphase alternating current having N phases at a predetermined voltage to N phase lines (U, V, W), wherein N is an integer greater than or equal to 2, and wherein for each two phases, the phase shift between the two phases is 2pik / N, wherein k is an integer in the range of 1 to N-1 in each case; wherein for each of the at least one power source, a number N of power connections (20) is provided, each of which is connected to at least one of the tube segments in the current input region, wherein each of the power connections is connected to one of the phase lines of the power source; and wherein a star point (34) is formed in the at least one power source, at which the phase lines of the power source are connected, characterized in that the star point is not connected to a ground connection.

2. The apparatus of claim 1, wherein, The chemical reaction is a chemical reaction carried out at least partially at a temperature of at least 500°C.

3. The apparatus (100, 200) of the preceding claim 1, wherein A neutral conductor (N) is provided which connects the star bridge (22) with the star point (34).

4. The apparatus (100, 200) of the preceding claim 1, wherein The star bridge (22) is not connected to a ground connection (4).

5. The apparatus (100, 200) of the preceding claim 1, wherein A main ground rail is provided and the feed section (152, 252) and the discharge section (154, 254) are electrically conductively connected to the main ground rail.

6. The apparatus (200) of the preceding claim 1, wherein The feed section (252) and the discharge section (254) are arranged spatially adjacent to each other and electrically conductively connected to each other by a connecting element (256).

7. The apparatus (200) of claim 6, wherein, The distance between adjacent feed sections (252) and discharge sections (254) is less than one tenth of the size of the star bridge (22).

8. The apparatus (200) according to claim 6 or 7, wherein The distance between adjacent feed sections (252) and discharge sections (254) is less than 10 cm.

9. The apparatus (200) of claim 6, wherein, The connecting element (256) is electrically conductively connected to a ground connection (4) via a ground connection line (257).

10. The apparatus (200) of claim 6, wherein, The connecting element (256) is manufactured integrally.

11. The apparatus (200) of claim 10, wherein, The connecting element (256) is manufactured integrally with the feed section (252) and the discharge section (254).

12. The apparatus (200) according to any one of claims 10 or 11, wherein, The connecting element (256) is manufactured as a cast component, wherein one end of the ground connection line (257) is cast into the cast component.

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