Reactor and Method for Carrying Out a Chemical Reaction

Abstract

Disclosed is a reactor for carrying out a chemical reaction and a corresponding method. The reactor includes a vessel and one or more reaction tubes where a number of tube sections of the reaction tubes run between first second regions in the reactor vessel, and where the tube sections in the first region for the electrical heating of the tube sections can be electrically connected to the phase connections of a polyphase AC power source. Tube sections in the second region are electrically and conductively connected to one another as a whole by means of a single rigid connecting element, or in groups by means of a plurality of rigid connecting elements which are integrally connected to the reaction tubes and are arranged inside the reactor vessel. A corresponding method is also the subject-matter of the present invention.

Claims

1. A reactor for carrying out a chemical reaction, the reactor comprising: a reactor vessel and one or more reaction tubes, wherein a number of tube sections of the one or more reaction tubes run between a first region for electrical heating and a second region within the reactor vessel, and wherein the tube sections in the first region electrically connected to the phase connections of a polyphase alternating current source, and used as electrical resistors in order to generate heat and; the tube sections in the second region are either: (i) electrically conductively connected to one another as a whole by means of a single rigid connecting element or in groups by means of a plurality of rigid connecting elements, which are integrally connected to the one or more reaction tubes; or (ii) are arranged within the reactor vessel as one or more star bridges effecting a potential equalization, wherein the one or more connecting elements is or are configured for operation at a temperature of more than 700° C.

2. A reactor according to claim 1, wherein the chemical reaction is an endothermic chemical reaction.

3. A reactor according to claim 1, wherein each of the tube sections comprise two tube sections of a plurality of reaction tubes which are arranged at least partially side by side in the reactor vessel, wherein the respective two tube sections of the plurality of reaction tubes pass into one another in the first region in each case via a U-bend.

4. A reactor according to claim 3, wherein one tube section of each of the two tube sections of the plurality of reaction tubes is connected to a first of the plurality of connecting elements and the other tube section of the respective two tube sections of the plurality of reaction tubes is connected to a second of the plurality of connecting elements.

5. A reactor according to claim 3, wherein both tube sections of the plurality of reaction tubes are connected to the one connecting element.

6. A reactor according to claim 1, in which the tube sections are an even number of four or more tube sections of a reaction tube or one of a plurality of reaction tubes serially connected to one another via a number of U-bends, wherein the number of U-bends is one less than the number of tube sections serially connected to one another via the U-bends, and wherein the U-bends, beginning with a first U-bend in the first region, are arranged alternately in the first region and in the second region.

7. A reactor according to claim 6, in which the U-bend or U-bends arranged in the second region is or are formed in the rigid connecting element and in which the tube sections extend from the connecting element the second region to the first region.

8. A reactor according to claim 6, in which the connecting element is cast onto the formed tube sections previously provided with the U-bend or U-bends in the second region or connected thereto.

9. A reactor according to claim 6, wherein the U-bend or U-bends in the second region are formed in the connecting element and the tube sections are welded to the connecting element.

10. A reactor according to claim 1, which is designed as a reactor for steam cracking.

11. A reactor according to claim 1, wherein the tube sections in each case comprise a tube section of a plurality of reaction tubes, wherein the tube sections are arranged side by side in the reactor vessel in a fluidically unconnected manner and are in each case connected to a feed section in the first region and an extraction section in the second region.

12. A reactor according to claim 11, which is designed as a reactor for steam reforming, dry reforming or the catalytic dehydrogenation of alkanes.

13. A reactor according to claim 1, wherein the connecting element and the tube sections are formed from the same material or from materials whose electrical conductivities differ from one another by not more than 50%.

14. A reactor according to claim 1, wherein the connecting element and the tube sections are formed from the same material or from materials whose electrical conductivities differ from one another by not more than 30%.

15. A reactor according to claim 1 wherein the connecting element and the tube sections are formed from the same material or from materials whose electrical conductivities differ from one another by not more than 10%.

16. A reactor according to claim 1 wherein the connecting element and the tube sections are formed from chrome-nickel steels which comprise 0.1 to 0.5 wt % carbon, 20 to 50 wt % chromium, 20 to 80 wt % nickel, 0 to 2 wt % niobium, 0 to 3 wt % silicon, 0 to 5 wt % tungsten and 0 to 1 wt % other constituents, preferably 20 to 40 wt % chromium, 20 to 50 wt % nickel, 0 to 10 wt % silicon, 0 to 10 wt % aluminum and 0 to 4 wt % niobium, wherein the contents of the specified constituents in each case complement one another to form the non-ferrous fraction.

17. A reactor according to claim 1, wherein the connecting element is surrounded at least in part by a conducting element made of a material rich in molybdenum, tungsten, tantalum, niobium and/or chromium or formed therefrom and/or which has a higher specific electrical conductivity than the material from which the connecting element is formed.

18. A method for carrying out a chemical reaction using a reactor, which has a reactor vessel and one or more reaction tubes, wherein a number of tube sections of the one or more reaction tubes in each case run between a first region and a second region within the reactor vessel, and wherein the tube sections in the first region for the heating of the tube sections in each case are electrically connected to the phase connections of a polyphase alternating current source, the tube sections as electrical resistors in order to generate heat; electrically conductively connecting the tube sections in the second region to one another as a whole by means of a single rigid connecting element or in groups by means of a plurality of rigid connecting elements, which are integrally connected to the one or more reaction tubes and are arranged within the reactor vessel as one or more star bridges effecting a potential equalization; and operating the one or more connecting elements at a temperature of more than 700° C.

Description

DESCRIPTION OF THE FIGURES

[0068] FIG. 1 schematically illustrates a reactor for carrying out a chemical reaction according to a non-inventive development.

[0069] FIG. 2 schematically illustrates a reactor for carrying out a chemical reaction according to a development of the disclosed embodiments.

[0070] FIG. 3 schematically illustrates a reactor for carrying out a chemical reaction according to a further development of the disclosed embodiments.

[0071] FIG. 4 schematically illustrates a connecting element for use in a reactor according to a development of the disclosed embodiments.

[0072] FIG. 5 schematically illustrates a connecting element for use in a reactor according to a development of the disclosed embodiments.

[0073] FIG. 6 schematically illustrates a connecting element in cross-section for use in a reactor according to a development of the disclosed embodiments.

[0074] FIG. 7 illustrates resistors in an arrangement for use in a reactor according to a development of the disclosed embodiments.

[0075] FIGS. 8A to 8C illustrate reaction tubes and corresponding arrangements for use in a reactor according to a development of the disclosed embodiments.

[0076] FIGS. 9A and 9B illustrate reaction tubes and corresponding arrangements for use in a reactor according to a development of the disclosed embodiments.

[0077] FIGS. 10A to 10C illustrate further reaction tubes for use in a reactor according to a development of the disclosed embodiments.

[0078] In the following figures, elements that correspond to one another functionally or structurally are indicated by identical reference symbols and for the sake of clarity are not repeatedly explained. If components of devices are explained below, the corresponding explanations will in each case also relate to the methods carried out therewith and vice versa.

[0079] FIG. 1 schematically illustrates a reactor for carrying out a chemical reaction according to a non-inventive development.

[0080] The reactor here designated 300 is set up to carry out a chemical reaction. For this purpose, it has in particular a thermally insulated reactor vessel 10 and a reaction tube 20, wherein a number of tube sections of the reaction tube 20, which are designated here by 21 only in two cases, run respectively between a first zone 11′ and a second zone 12′ in the reactor vessel 10. The reaction tube 20, which will be explained in more detail below with reference to FIG. 2, is attached to a ceiling of the reactor vessel or to a support structure by means of suitable suspensions 13. In a lower region, the reactor vessel can in particular have a furnace (not illustrated). It goes without saying that a plurality of reaction tubes can be provided in each case here and subsequently.

[0081] FIG. 2 schematically illustrates a reactor for carrying out a chemical reaction according to a development of the disclosed embodiments, which are overall denoted by 100.

[0082] The zones previously designated 11′ and 12′ here take the form of regions 11 and 12, wherein the tube sections 21 for heating the tube sections 21 in the first regions 11 can in each case be electrically connected to the phase connections U, V, W of a polyphase alternating current source 50. Corresponding phase connections can also be designated according to convention as L1, L2, L3 or A, B, C as well as other abbreviations. Switches and the like as well as the specific type of connection are not illustrated.

[0083] In the development of the disclosed embodiments illustrated here, the tube sections 21 are electrically conductively connected to one another in the second regions 12 by means of a connecting element 30 which is integrally connected to the one or more reaction tubes 20 and is arranged within the reactor vessel 10. A neutral conductor may also be connected thereto.

[0084] In the reactor 100 illustrated here, a plurality of tube sections 21 of a reaction tube 20 (although a plurality of such reaction tubes 20 may be provided) are thus arranged side by side in the reactor vessel 10. The tube sections 21 pass into one another via U-bends 23 (only partially denoted) and are connected to a feed section 24 and an extraction section 25.

[0085] A first group of the U-bends 23 (at the bottom in the drawing) is arranged side by side in the first region 11 and a second group of the U-bends 23 (at the top in the drawing) is arranged side by side in the second region 12. The U-bends 23 of the second group are formed in the connecting element 30, and the tube sections 21 extend from the connecting element 30 in the second region 12 to the first region 11.

[0086] FIG. 3 schematically illustrates a reactor, which is overall denoted by 200, for carrying out a chemical reaction according to a development of the disclosed embodiments.

[0087] In the reactor 200, the tube sections—here in contrast denoted by 22—in each case comprise a tube section 22 consisting of a plurality of reaction tubes 20, wherein the tube sections 22 are arranged side by side in the reactor vessel 10 in a fluidically unconnected manner and are in each case connected to feed sections 24 and extraction sections 25. For the remaining elements, reference is expressly made to the above explanations relating to the preceding figures.

[0088] FIG. 4 schematically illustrates a connecting element 30 for use in a reactor according to a development of the disclosed embodiments, for example in the reactor 100 according to FIG. 2.

[0089] Since the elements illustrated in the figure have essentially already been explained above, reference is expressly made to the above explanations, in particular to FIGS. 1 and 2. Not shown here are the suspensions 13, illustrated additionally in the form of asterisk symbols, onto which, in the development illustrated here, the tube sections 21 and the U-bends 23 formed in the connecting element 30 for example during casting, are welded.

[0090] FIG. 5 schematically illustrates a connecting element 30 for use in a reactor, according to a development of the disclosed embodiments, such as has not been previously illustrated.

[0091] As shown here, within the scope of the disclosed embodiments, a star-shaped (in the geometric sense) arrangement of the tube sections 21 can also be made, the connecting element 30 being at the center of this arrangement. It goes without saying that a plurality of such star-shaped arrangements can also be provided, for example, side by side or stacked on top of each other. Unlike the arrangement as illustrated in FIG. 5, the tube sections may also extend upwardly or downwardly, for example, from the drawing plane.

[0092] FIG. 6 schematically illustrates a connecting element 30 in cross-section for use in a reactor according to a development of the disclosed embodiments, once again, for example, in the reactor 100 according to FIG. 2.

[0093] As illustrated here, the connecting element 30 is surrounded at least in part by a conducting element 31 made of a previously explained material with suitable conductivity and which, for example, takes the form of a U-profile. The connecting element 30 can be formed, for example, from a high-alloy chrome-nickel steel, for example from the ET45 micro-material mentioned. The conducting element 31 improves the potential equalization, as already explained.

[0094] FIG. 7 illustrates resistors in an arrangement for use in a reactor according to a development of the disclosed embodiments or, here, advantageously to achieve resistance relationships of the elements with respect to one another. The arrangement is particularly suitable for use in a reactor 100 according to FIG. 2.

[0095] Resistors in the connecting element 30 are indicated in FIG. 7 by Rb, i, in the feed and extraction sections 24 and 25 by Rh, i, and in the suspensions 13 by Rn, i. As also shown in FIG. 7 itself, Rh,i>>Rn,i>>Rb,i should advantageously apply.

[0096] In cracker furnaces, in addition to the reaction tubes 20 previously shown in FIGS. 1 and 2, which are commonly referred to as 6-passage coils, and the six straight tube sections 21 having two 180° bends, i.e., U-bends 23, above or in the second region 12, and three 180° bends, i.e., U-bends 23, below or in the first region 11, variants with fewer passages can also be used. For example, so-called 2-passage coils have only two straight tube sections 21 and only one 180° bend or U-bend 23. Transferred to electrical heating, this variant can be regarded as a combination of 6-passage cracker furnaces (FIGS. 1 and 2) and reforming furnaces (FIG. 3, with reaction tubes without U-bends 23):

[0097] The flow can be fed in at one point per reaction tube 21 at the lower (or only) U-bend. In each case, M reaction tubes can be electrically coupled to one another, with a phase shift of 360°/M and with a common connecting element 30. In a first alternative, a particularly large connecting element 30 can be used per coil package or for all reaction tubes 20 considered in each case. In a second alternative, however, the use of two smaller-sized connecting elements 30 is also possible.

[0098] The first alternative just explained is illustrated in FIG. 9B, the second alternative just explained in FIG. 9C in a cross-sectional view through the tube sections 21, wherein a corresponding reaction tube 20 is shown in FIG. 9A in a view perpendicular to the views in FIGS. 9B and 9C. Reference is made to FIG. 1 for the designation of the corresponding elements. It goes without saying that the connecting element or elements 30 with the U-bends 23 possibly arranged there on the one hand and the other U-bends 23 on the other hand with the connections to the phases U, V, W are arranged in different planes corresponding to the first and second regions 11, 12 of a reactor.

[0099] This concept can also be applied correspondingly to coils or reaction tubes 20 having four passages or tube sections 21 (so-called 4-passage coils), in this case with one, two or four star bridges or connecting elements 30. A corresponding example is shown in FIGS. 9A and 9B, four connecting elements being shown in FIG. 9B. For improved illustration, the U-bends 23 are shown here by dashed lines (U-bends in the second region 12 of the reactor) and by unbroken lines (U-bends in the first region 11). For the sake of clarity, the elements are only partially provided with reference numerals.

[0100] Reference has already been made to FIGS. 10A and 10B, which illustrate further reaction tubes for use in a reactor according to a development of the disclosed embodiments. The reaction tubes and tube sections are here only in some cases provided with reference numerals. Feed and extraction sections may be deduced from the flow arrows shown.