DARK RADIATOR

Abstract

A dark radiator includes a burner, a fan and a radiant tube which is connected to an exhaust gas discharge line, wherein the burner is connected to a fuel gas supply, wherein the fan is designed to supply the burner with combustion air, wherein the burner is designed to output a flame into the radiant tube, wherein the fuel gas supply is connected to a hydrogen source.

Claims

1. A dark radiator, having a burner (1, 5, 6, 7), a fan (2), and a radiant tube (3), which is connected to an exhaust gas discharge line, wherein the burner (1) is connected to a fuel gas supply, wherein the fan (2) is set up for supplying combustion air to the burner (1), wherein the burner (1) is set up for outputting a flame into the radiant tube (3, 3), wherein the fuel gas supply is connected to a hydrogen source.

2. The dark radiator according to claim 1, wherein the fan (2) is connected to an ejector (21) having a suction connector connected to the hydrogen supply (23), wherein the combustion air drawn in by the fan (2) serves as a driving medium, so that a hydrogen/combustion air mixture is supplied to the burner (1) by the fan (2).

3. The dark radiator according to claim 1, wherein the burner (4) comprises a gas jet (11) and a mixing tube (43), which tube is supplied with hydrogen by the gas jet (11), wherein the mixing tube (43) is flushed with combustion air by means of the fan (2), wherein the gas jet (11), together with the mixing tube (43), forms an ejector, wherein the driving medium of the ejector is hydrogen introduced by means of the gas jet, and the medium drawn into the mixing tube (43) is combustion air situated in the radiant tube (3, 3), and wherein an ignition apparatus for igniting the hydrogen/combustion air mixture follows at a distance from the mixing tube (43) in the flame direction.

4. The dark radiator according to claim 1, wherein the burner (7) comprises a hydrogen jet (41), wherein the fan (2) is set up for flushing the hydrogen jet (41) with combustion air, and wherein no fuel gas mixing chamber is provided for pre-mixing fuel gas and combustion air, and the gas jet is supplied exclusively with fuel gas.

5. The dark radiator according to claim 3, wherein a combustion air mixing chamber is arranged to precede the burner (1, 5, 6) in the flame direction, which chamber is connected to a combustion air source and to the exhaust gas discharge line.

6. The dark radiator according to claim 5, wherein the fan (2) is arranged to precede the burner (1) in the flame direction, and the combustion air mixing chamber is arranged within the fan (2).

7. The dark radiator according to claim 5, wherein the connection between the exhaust gas discharge line (62) and the combustion air mixing chamber comprises a branching-off device (64) by means of which the ratio of the branched-off exhaust gas volume stream and the combustion air volume stream is determined.

8. The dark radiator according to claim 7, wherein the branching-off device (64) comprises an adjustment device by means of which the ratio of the exhaust gas volume stream and the combustion air volume stream can be set.

9. The dark radiator according to claim 1, wherein the burner serves as a primary burner (7) that is followed by a secondary burner (8) in the radiant tube (3), at a distance in the flame direction, the fuel gas supply of which secondary burner is connected to a hydrogen source as a fuel gas source, wherein the exhaust gas stream of the preceding primary burner (7) is supplied to the secondary burner (8) as combustion air.

10. The dark radiator according to claim 9, wherein an equalization element (31) for balancing out thermally caused length changes within the radiant tube (3) is placed in line between the primary burner (7) and the secondary burner (8).

Description

[0014] Other further developments and embodiments of the invention are indicated in the remaining dependent claims. Exemplary embodiments of the invention are shown in the drawings and will be described in detail below. The figures show:

[0015] FIG. 1 the schematic representation of a dark radiator;

[0016] FIG. 2 the schematic representation of a dark radiator in a further embodiment;

[0017] FIG. 3 the schematic representation of a dark radiator in a third embodiment;

[0018] FIG. 4 the schematic representation of a dark radiator in a fourth embodiment, with a primary and secondary burner;

[0019] FIG. 5 the schematic representation of a dark radiator in a further embodiment, with a primary and secondary burner.

[0020] The dark radiator according to FIG. 1, selected as an exemplary embodiment, comprises a burner 1 that is connected to a fan 2 and followed by a radiant tube 3. The radiant tube 3 is merely indicated in FIG. 1; the radiant tube 3 can certainly extend over several meters in length and be formed from multiple radiant tube elements. In the exemplary embodiment, the radiant tube 3 is formed as a highly heat-resistant stainless steel tube. Alternatively, special steels having a thermally applied aluminum oxide layer can also be used. In the exemplary embodiment, the radiant tube 3 is enclosed by a reflectornot shownwhich is formed, in the exemplary embodiment, from surface-structured sheet aluminum and has bulkhead plates on both sides, to reduce convective losses.

[0021] The burner 1 comprises a gas jet 11 that serves as a gas/air mixture jet and is provided, in the exemplary embodiment, with a flashback barrier, and is connected to the fan 2. At a distance from the gas jet 11, an ignition electrode 12 is arranged in the burner 1. The fan 2 is connected to an ejector 21 on its suction side, the drive connector of which ejector is connected to a combustion air supply 22 and the suction connector of which ejector is connected with a hydrogen supply 23. Here, the combustion air drawn in by the fan 2 serves as a driving medium, which is brought about by means of drawing in the hydrogen. On the pressure side, a hydrogen/combustion air mixture is supplied to the gas jet 11 by the fan 2 in this way, which mixture is ignited after it exits through the gas jet 11, by means of the ignition electrode 12, and thereby a flame that extends through the radiant tube 3 is generated.

[0022] In the exemplary embodiment according to FIG. 2, a burner 4 is provided, which in turn is connected with a fan 2 and followed by a radiant tube 3. The burner 4 comprises a hydrogen jet 41 that is connected to a hydrogen supply 42 and which in turn is oriented in line with the longitudinal center axis of the radiant tube 3. Here, a gas jet that exclusively has hydrogen applied to it is referred to as a hydrogen jet. The hydrogen jet projects into a mixing tube 43 that runs coaxially to the radiant tube 3, wherein a radial suction gap of an ejector formed by the hydrogen jet 41 and the mixing tube 43 is formed between mixing tube 43 and hydrogen jet 41. The mixing tube 43 is held in the burner 4 by way of a separating shutter 45 provided with flushing openings, which shutter encloses the tube. On its end that lies opposite the hydrogen jet 41, a flashback barrier 431 is arranged in the mixing tube 43. Furthermore, a thermosensor 432 for detecting a possible flame flashback is arranged in the mixing tube 43.

[0023] The fan 2 is oriented in such a manner that it flushes the hydrogen jet 41 and the mixing tube 43 with combustion air 35. By means of the hydrogen stream introduced into the mixing tube 43 by way of the hydrogen jet 41, combustion air 25 is drawn in by way of the suction gap 44, which air mixes with the hydrogen. The hydrogen/combustion air mixture exiting from the mixing tube 43 is ignited by means of the ignition electrode 46 arranged at a distance from the mixing tube 43, and thereby a flame is formed, which extends into the radiant tube 3 over its length.

[0024] A part of the combustion air 35 blown into the burner 1 by the fan 2 flows through the flushing openings of the separating walls 45 and flushes the flame that extends into the radiant tube 3, which flame is thereby cooled. The ejector formed by the hydrogen jet 41 and the mixing tube 43 is configured in such a manner that combustion air having an air number of 2.5 is supplied to the hydrogen, and thereby a temperature of about 900? C. is achieved.

[0025] In the exemplary embodiment according to FIG. 3, the dark radiator comprises a burner 5 that is connected to a fan 2 and followed by a radiant tube 3. The radiant tube 3 has a U-shaped progression, followed by a branching tube 6 that is connected to the fan 2 by way of a suction tube 24. The burner 5 in turn comprises a hydrogen jet 51 that is connected to a hydrogen supply 52. The hydrogen jet 51 is oriented in the direction of the center longitudinal axis of the radiant tube 3. An ignition electrode 53 for igniting the hydrogen is positioned at a distance from the hydrogen jet 51.

[0026] The ejector tube 6 comprises a main tube piece 61 by way of which the radiant tube 3 is connected with the suction tube 24. An exhaust gas discharge tube 62 branches off from the main tube piece 61 and, at a distance from the latter, a combustion air supply tube 63 branches off. A recirculation shutter 64 is arranged in the main tube piece 61, between the exhaust gas supply tube 62 and the combustion air supply tube 63. The combustion air stream 631 drawn in by the fan 2, by way of the suction tube 24, serves as the driving medium of the ejector tube 6, by way of which a part of the exhaust gas stream 621 is drawn in by means of the recirculation shutter 64. The exhaust gas/combustion air mixture produced in this manner is introduced into the burner 5 by means of the fan 2, where it flushes the hydrogen jet 51. The proportion of the exhaust gas stream in the combustion air stream can be adjusted by means of the recirculation shutter 64, and thereby, in turn, the oxygen content of the exhaust gas/combustion air stream mixture that flushes the hydrogen jet 51 is determined. The main exhaust gas stream is conducted away by way of the exhaust gas discharge tube 62.

[0027] The burner 5, the radiant tube 3, the ejector tube 6, and the fan 2 connected to the suction tube 24 are connected to one another, in each instance, by way of flange connections.

[0028] In the exemplary embodiment according to FIG. 4, two burners are arranged in the radiant tube 3, a primary burner 7 and a secondary burner 8 which follows the former in the flame direction. The primary burner 7 and the secondary burner 8 correspond to the burner 5 explained in the exemplary embodiment described above. These in turn comprise a hydrogen jet 71, 81, which is connected to a hydrogen supply 72, 82, wherein an ignition electrode 73, 83 is positioned at a distance from the hydrogen jet 71, 81. The primary burner 7 is connected to a fan 2, the suction connector of which is connected to a combustion air supply 22. The primary burner 7 is followed by a radiant tube 3 that is configured in U shape and connected with the secondary burner 8 by way of an equalization element 31. In turn, a further radiant tube 3 follows the secondary burner 8, which tube is once again configured in U shape in the exemplary embodiment.

[0029] The hydrogen jet 71 of the primary burner 7 is flushed with combustion air by the fan 2. The hydrogen/combustion air mixture that forms ahead of the hydrogen jet 71 is ignited by the ignition electrode 73, and thereby a first flame forms at a distance ahead of the hydrogen jet 71. The exhaust gas stream of this first flame flows through the equalization element 32 and flushes the hydrogen jet 81 of the secondary burner 8. The exhaust gas stream/hydrogen mixture that forms ahead of the hydrogen jet 81 has a sufficiently high oxygen content so that it can be ignited by the ignition electrode 83, and thereby a second flame is formed, which extends along the second radiant tube 3. The exhaust gas stream of this second flame is conducted away out of the second radiant tube 3. The equalization element 31 positioned in the section of the radiant tube 3 exposed to a high temperature gradient by means of the secondary burner 8 serves for equalization of thermally caused length changes within the radiant tube. This element is configured as an axial compensator in the exemplary embodiment, which absorbs the movements of the pipeline along the axis.

[0030] In this exemplary embodiment, combustion air is supplied to the primary burner 7 by way of the fan 2, which air flushes the hydrogen jet 71 of the primary burner 7. In a modified embodiment, the fan 2, which precedes the primary burner 7, can also be connected to an ejector, in accordance with the first exemplary embodiment, wherein the combustion air drawn in serves as a driving medium, by way of which combustion air is drawn in from the second radiant tube 3. In a further modified embodiment, the second radiant tube 3 can also be connected to the suction line of the fan 2 by way of an ejector tube, as described in the third exemplary embodiment. In this manner, the flame temperature of the first flame of the primary burner 7 can also be adjusted. Furthermore, in this way a further reduction of the nitrogen oxide content of the exhaust gas that is conducted away is also made possible.

[0031] In the exemplary embodiment according to FIG. 5, the primary burner 7 is configured in accordance with the burner of the exemplary embodiment according to FIG. 2, wherein the hydrogen jet 71 in turn projects into a mixing tube 74, so that a suction gap 75 is formed between hydrogen jet 71 and mixing tube 74. On its end that lies opposite the hydrogen jet 71, a flashback barrier 741 is once again arranged in the mixing tube 74. For the remainder, the structure of the dark radiator of this exemplary embodiment corresponds to the exemplary embodiment according to FIG. 4, wherein in this exemplary embodiment, as well, the embodiments listed there for mixing part of the exhaust gas stream of the second radiant tube 3 into the combustion air drawn in by the fan 2 are possible.