METHOD FOR PROVIDING SYNTHESIS GAS BY MEANS OF AN ADDITIONAL ELECTRIC HEATER

Abstract

A reformer for steam reforming a hydrocarbon-containing mixture, including a combustion chamber, a burner arranged within the combustion chamber, a first reactor tube which is arranged at least in sections within the combustion chamber, a catalyst arranged inside the first reactor tube, and an electrically heatable heating element is arranged inside the first reactor tube.

Claims

1.-21. (canceled)

22. A reformer for the steam reforming of a hydrocarbon-containing mixture, at least comprising: a combustion chamber, a burner disposed within the combustion chamber, a first reactor tube which is disposed at least sectionally within the combustion chamber, a catalyst disposed within the first reactor tube, and an electric heating element disposed within the first reactor tube.

23. The reformer of claim 22 further comprising a second reactor tube with a catalyst disposed within the second reactor tube, the second reactor tube free of a heating element.

24. The reformer of claim 22 wherein the first reformer tube has protrusions or constrictions in the region of the electric heating element.

25. The reformer of claim 22 wherein the electric heating element comprises an inductively heatable heating element.

26. The reformer of claim 25 wherein the inductively heatable heating element has at least one heating tube and a metallic wire or a metallic coating wound at least sectionally around the heating tube.

27. The reformer of claim 26 wherein some or all of the heating tube has a metallic surface.

28. The reformer of claim 26 wherein the metallic wire lies on the heating tube via notches.

29. The reformer of claim 22 wherein the heating tube is filled with the catalyst or with a second catalyst different from the catalyst.

30. The reformer of claim 22 wherein the catalyst is disposed within the first reactor tube and within the heating tube.

31. The reformer of claim 22 wherein the ratio of the diameter of the first reactor tube, ∅.sub.2a, to the diameter of the heating tube, ∅.sub.6, expressed as ∅.sub.2a/∅.sub.6, is from 100 to 2.

32. The reformer of claim 26 wherein the metallic wire and/or the metallic surface and/or the metallic coating comprises one or more of iron, cobalt, nickel, copper, silver, and chromium.

33. The reformer of claim 26 wherein the metallic wire and/or the metallic coating are connected to an electrical alternating current source.

34. The reformer of claim 22 wherein the electric heating element comprises an electrical resistance heating element.

35. The reformer of claim 34 wherein the electrical resistance heating element comprises an electrical heating resistor and a heating jacket.

36. The reformer of claim 35 wherein the heating jacket comprises electrical insulators.

37. The reformer of claim 34 wherein the electrical resistance heating element comprises a first electrical heating resistor and a second heating resistor.

38. The reformer of claim 22 wherein the catalyst comprises a ferromagnetic catalyst

39. A plant for ammonia synthesis, hydrogen synthesis, methanol synthesis and/or as an ammonia synthesis-urea synthesis complex, comprising the reformer of claim 22.

40. A method for producing synthesis gas, comprising: providing a hydrocarbon-containing starting mixture and steam; charging a reformer with the provided hydrocarbon-containing starting mixture and steam, wherein the reformer comprises: a combustion chamber, a burner disposed within the combustion chamber, a first reactor tube which is disposed at least sectionally within the combustion chamber, a catalyst disposed within the first reactor tube, and an electric heating element disposed within the first reactor tube, and obtaining a synthesis gas mixture.

41. The method of claim 40 wherein said charging step takes place at a temperature of 300° C. to 700° C. under a pressure of 20 bar to 50 bar.

Description

[0040] Additionally, the invention is elucidated in more detail by means of the following figures: these figures do not limit the scope of protection of the invention, instead serving only for illustrative elucidation. The figures are not to scale.

[0041] FIG. 1 shows a schematic drawing of the reformer of the invention for the steam reforming of a hydrocarbon-containing mixture,

[0042] FIG. 2 shows a schematic drawing of the first reactor tube of the invention,

[0043] FIG. 3 shows an enlarged detail of the first reactor tube,

[0044] FIG. 4 shows an enlarged detail of the electrical resistance heating element,

[0045] FIG. 5 shows a schematic drawing of a further embodiment of the first reactor tube of the invention,

[0046] FIG. 6 shows an enlarged detail of a preferred electrical resistance heating element, and

[0047] FIG. 7 shows a schematic drawing of a preferred first reactor tube.

[0048] FIG. 1 shows a schematic drawing of the reformer of the invention for the steam reforming of a hydrocarbon-containing mixture. The reformer comprises a combustion chamber (1) and burners (4) disposed within the combustion chamber. A first reactor tube (2a) is disposed at least sectionally within the combustion chamber (1). The expression “at least sectionally” means in the sense of the invention that at least a part or the whole part of the first reactor tube runs within the combustion chamber (1). Disposed within the first reactor tube (2a) is a catalyst (3), not shown. Also disposed within the first reactor tube (2a) is an electrically inductively heatable heating element (5a). In addition, furthermore, there may be second reactor tubes (2b) with catalyst (3), not shown, which for reasons of cost or for temperature control, for example, may include no inductively heatable heating element (5a).

[0049] FIG. 2 shows a schematic drawing of the first reactor tube (2a) of the invention. Located within the first reactor tube (2a) is a catalyst (3) and an inductively heatable heating element (5a). The inductively heatable heating element (5a) comprises a heating tube (6), a metallic wire (7a) wound at least sectionally around the heating tube (6) like a coil (or metallic coating (7b)) and may likewise be filled with the catalyst (3). In principle, the catalysts (3) within the inductively heatable heating element (5a) and within the space between the inductively heatable heating element (5a) and the interior of the first reactor tube (2a) may be identical or else different. The metallic wire (7a) wound like a coil around the heating tube (6) is connected to an alternating current source, not shown. The heating of the heating tube (6) via the wound metallic wire (7a) allows the first reactor tube (2a) to be heated from the inside and therefore lowers the physical stresses through the simultaneous introduction of heat on the part of the burners (4). A hydrocarbon-containing starting mixture (9) and steam (10) enter the first reactor tube (2a) and depart the first reactor tube (2a) as a synthesis gas mixture (11).

[0050] FIG. 3 shows an enlarged detail of the first reactor tube (2a). The heating tube (6) is filled (optionally) with catalyst (3) and at least sectionally, for better thermal conduction, has a (thermally conducting) metallic coating (7c). The metallic wire (7a) wound like a coil around the heating tube (6) is connected to an alternating current source, not shown. Notches (8) in the heating tube (6) improve the hold of the metallic wire (7a) on the surface of the heating tube, and additionally this creates a planar surface (8a), which allows improved transfer of heat by means of thermal conduction.

[0051] FIG. 4 shows an enlarged detail of the electrical resistance heating element (5b). The electrical resistance heating element (5b) comprises an electrical heating resistor (13) and a heating jacket (12). The electrical heating resistor (13) may be electrically connected to a direct current source (indicated by +−) or an alternating current source, not shown.

[0052] FIG. 5 shows a schematic drawing of a further embodiment of the first reactor tube (2a) of the invention. Disposed within the first reactor tube (2a) is a catalyst (3). The electrical resistance heating element (5b) shown in FIG. 4 is disposed within the catalyst (3) and enables a more uniform heating of the catalyst (3) and reduces the physical stresses occurring within the first reactor tube (2a). The electrical resistance heating element (5b) may be configured, as shown in FIG. 5, as separate elements in each case or else as a connected totality, connected in series or in parallel, of respectively individual electrical resistance heating elements (5b1+5b2+5b3+ . . . ).

[0053] FIG. 6 shows an enlarged detail of a preferred electrical resistance heating element (5b). The electrical resistance heating element (5b) comprises a first electrical heating resistor (13a), a second electrical heating resistor (13b) and a heating jacket (12). The electrical heating resistors (13a/13b) may be electrically connected to a direct current source (indicated by +−) or to an alternating current source, not shown. The electrical resistance element (5b) may also comprise a plurality of first and second heating resistors (13a/13b). This is indicated schematically in the circle. The first electrical heating resistor (13a) and the second heating resistor (13b) may have different dimensions. This includes, for example, different lengths and diameters or else the arrangement of the electrical heating resistors (13a/13b) in the electrical resistance heating element (5b). By way of this arrangement it is possible to achieve different and adaptable heating powers on the part of the electrical resistance heating element (5b).

[0054] FIG. 7 shows a schematic drawing of a preferred first reactor tube (2a). The electrical resistance element (5b) comprises a plurality of first and second heating resistors (13a/13b). These heating resistors (13a/13b) are preferably different in their dimensions in terms of the heating power. The electrical resistance element (5b) is disposed in the first reactor tube (2a) via an electrical contacting/mechanical securement (14). The first reactor (2a) has a protrusion (15) in the region of the electrical resistance element (5b). These protrusions (15) or else constrictions enable an individually adjustable heating of individual sections of the first reformer tubes (2a).

LIST OF REFERENCE SYMBOLS

[0055] (1) combustion chamber

[0056] (2a) first reactor tube

[0057] (2b) second reactor tube

[0058] (3) catalyst

[0059] (4) burner

[0060] (5) electrically heatable heating element

[0061] (5a) inductively heatable heating element

[0062] (5b) electrical resistance heating element

[0063] (6) heating tube

[0064] (7a) metallic wire

[0065] (7b) metallic coating

[0066] (8) notches

[0067] (8a) contact face

[0068] (9) hydrocarbon-containing starting mixture

[0069] (10) steam

[0070] (11) synthesis gas mixture

[0071] (12) heating jacket

[0072] (13) electrical heating resistor

[0073] (13a) first electrical heating resistor

[0074] (13b) second electrical heating resistor

[0075] (13i) further i-th heating resistor with i greater/equal to 3 and i (integer) =3, 4, 5, 6, 7, . . .

[0076] (14) electrical contacting/mechanical securement

[0077] (15) protrusion/constriction of the first reactor tube