Burner and method for operating same

Abstract

The invention relates to a burner (10) for a furnace, kiln, anode furnace, tunnel kiln or the like, and to a method for operating a burner on such a furnace, wherein: the burner is designed to be arranged at a stokehole (11) of a combustion chamber (29) of the furnace; the burner has a fuel line (13) and a nozzle device (15); a fuel can be supplied to the nozzle device; the nozzle device has a burner mouth (16) which can be arranged in the stokehole; the fuel can be introduced into the combustion chamber via the burner mouth; and the burner mouth is formed from a ceramic fiber composite material.

Description

[0001] March 10, 2026

[0002] INNOVATHERM G / IOT-020-WO Prof. Dr. Leisenberg GmbH + Co. KG Scu / edm 35510 Butzbach

[0003] Burner and operating procedures

[0004] The invention relates to a burner and a method for operating a burner for a furnace, kiln, anode kiln, tunnel kiln or the like, wherein the burner is designed for arrangement at a stoking hole of a combustion chamber of the furnace, wherein the burner has a fuel line and a nozzle device, wherein fuel can be supplied to the nozzle device via the fuel line, wherein the nozzle device has a burner mouth that can be arranged in the stoking hole, and wherein the fuel can be introduced into the combustion chamber via the burner mouth.

[0005] Such burners are well-known and regularly used to introduce large amounts of heat energy into furnaces or similar devices. For example, gas burners are used in the ceramics industry to operate kilns. These types of burners can also be used in the production of anodes required for the molten salt electrolysis process used to produce primary aluminum. These anodes are first manufactured as so-called "raw anodes" using a shaping process and subsequently sintered in an anode ring furnace. This sintering process takes place in a defined heat treatment process in which the anodes undergo three phases: a heating phase, a sintering phase, and a cooling phase. In the heating phase, the raw anodes are heated or preheated to sintering temperatures of approximately 1100°C.The raw anodes are stacked in the furnace shafts and hermetically sealed with petroleum coke granules to prevent oxidation. Alongside the shafts run fire lanes, at the top of which stokeholes are formed. These stokeholes are fitted with burners or, when not in use, closed with stokehole covers. The burners are supplied with liquid or gaseous fuels via a fuel line, and combustion temperatures of up to 1250 to 1350°C can occur in the fire lanes during operation. This heat energy is then transferred to the furnace shafts containing the anodes. Such burners are known, for example, from DE 10 2022 131 222 Al.

[0006] During furnace operation, the burners are regularly moved from one stokehole to the next to ensure all anodes in the furnace are heated and cooled accordingly. This relocation is performed by operators who pull the burners out of the stokehole and place them in a designated holder. A still-glowing burner mouth can easily be damaged during this handling. Furthermore, the burner mouth is directly exposed to the hot furnace atmosphere within the stokehole, leading to rapid wear due to scaling. The burner mouth is typically made of steel and is thus subject to corrosion by the furnace atmosphere, necessitating regular replacement. Otherwise, a significant reduction in the burner mouth's diameter would compromise temperature uniformity within the furnace shaft and reduce burner performance.Good temperature homogeneity can be achieved when the burner mouth extends far into the furnace shaft. The present invention therefore aims to propose a burner and a method for operating a burner that enables improved operation.

[0007] This problem is solved with a burner having the features of claim 1, a furnace having the features of claim 16 and a method having the features of claim 17.

[0008] The burner according to the invention for a furnace, kiln, anode kiln, tunnel kiln or the like is designed for arrangement at a stoking hole of a combustion chamber of the furnace, wherein the burner has a fuel line with a nozzle device, wherein fuel can be supplied to the nozzle device via the fuel line, wherein the nozzle device has a burner mouth that can be arranged in the stoking hole, wherein the fuel can be introduced into the combustion chamber via the burner mouth, wherein the burner mouth is made of a ceramic fiber composite material.

[0009] The burner according to the invention is designed to be positioned at the stokehole of a furnace. The stokehole then forms an opening in the combustion chamber, which can be a combustion chamber, a heating gas passage, or the like. The burner mouth is positioned in the stokehole such that it opens into the combustion chamber. The fuel then exits the burner into the combustion chamber at the burner mouth. This process essentially results in flame formation and combustion of the fuel within the combustion chamber. The oxygen required for combustion may already be present in the combustion chamber or may enter it along with the fuel via the burner mouth. Because the burner mouth is made of a ceramic fiber composite material, it can become very hot, but significant wear of the burner mouth does not occur during operation at high temperatures.Unlike steel or other alloys, ceramic fiber composites do not develop scale. This makes the burner nozzle permanently usable and eliminates the need for regular replacement. Furthermore, the risk of damage to the burner nozzle during operator handling is reduced. Although the burner nozzle reaches a high temperature when the burner is withdrawn from the stokehole, it does not necessarily break if it comes into contact with the edge of the stokehole or other components. This is primarily due to the fiber reinforcement of the ceramic fiber composite, which makes it comparatively less sensitive to sudden impacts at high temperatures.The impact strength of the burner mouth made of ceramic fiber composite material is therefore comparatively higher than the impact strength of a metal burner mouth at a temperature of > 1000°C.

[0010] A free end of the fuel line can terminate within the burner nozzle. The fuel line can, for example, be designed as a rigid tube in sections, which can terminate in the burner nozzle as a component of the burner. The burner nozzle can then coaxially surround the tube. Furthermore, the burner nozzle can extend a short distance beyond a free end of the fuel line, thus preventing mechanical damage and excessive heating of the fuel line. The free end of the fuel line can be fitted with a nozzle insert or similar device.

[0011] The burner nozzle can be formed from a pipe section with an integrated flange. This pipe section can then coaxially surround the fuel line. The flange can be integrally formed with the pipe section, allowing it to be attached relative to the fuel line. The flange also facilitates particularly easy mounting of the burner nozzle to the other components of the nozzle assembly.

[0012] The burner can have an insert device that coaxially surrounds the burner mouth at least partially, preferably completely, along its longitudinal extent. The insert device can then serve to position the nozzle assembly as centrally as possible in the stoking hole and to protect the burner mouth from mechanical damage during burner handling. Furthermore, the insert device can also at least partially shield heat radiation from the combustion chamber acting on the nozzle assembly or the burner mouth, thus preventing excessive heating of the burner mouth or the nozzle assembly during operation. The insert device can, in particular, be designed as a self-contained, annular component that completely surrounds the burner mouth.

[0013] The insert can be flush with the burner mouth or extend beyond it. In the latter case, the insert can protrude further into the combustion chamber than the burner mouth. The insert and the burner mouth can also be approximately the same length. In both cases, the insert can protect the burner mouth from potential damage during handling, even in the axial direction.

[0014] Starting from a free end of the burner mouth, an annular gap can be formed between the insert and the burner mouth, at least in sections along its longitudinal extent. This prevents the burner mouth and the insert from coming into direct contact, and any forces acting on the insert are not transmitted to the burner mouth. Furthermore, no thermal stresses are generated in the burner mouth due to potentially different temperatures between the burner mouth and the insert. Thermal expansion of the burner mouth can then occur unimpeded. However, at least in sections, contact between the insert and the burner mouth can be provided, as long as mechanical decoupling of the burner mouth and insert is ensured.

[0015] The insert device can have a pot-shaped insert element, with an opening for fuel delivery at one free end of the insert element. The opening can be in the form of a through-hole, which may, for example, be circular. A recess in the form of a pipe stub, into which the burner nozzle opens, can also be formed at the opening. An annular gap can then be formed between the burner nozzle and the pipe stub.

[0016] Advantageously, the insert element can be made of a ceramic fiber composite material. The ceramic fiber composite material of the insert element can be different from or the same as that of the burner nozzle. In this case, the ceramic fiber composite material also prevents scaling of the insert element and its damage under sudden stress. The insert element can be relatively thin-walled, making it particularly lightweight and easy to handle. A cavity can be formed between the insert element and the burner nozzle. The insert element can therefore be designed as a hollow body.

[0017] The insert element can be at least partially, preferably completely, filled with a fibrous material. If the insert element has a cavity, this cavity can be lined with the fibrous material, which can be a ceramic fiber material. The fibrous material can be a non-woven fabric, a felt, or a fleece. Several layers of different fibrous materials can also be used to line the insert element. When the fibrous material rests against the burner mouth, it is flexible enough that no damage to the burner mouth can occur during relative movement between the fibrous material and the burner mouth. At the same time, the fibrous material can provide good thermal insulation against the burner mouth.

[0018] The burner can be equipped with a positioning device for arranging the nozzle assembly in the stokehole. The positioning device includes a stokehole cover that covers the stokehole, and the insert assembly and / or the burner mouth can be arranged on the stokehole cover on a side facing the combustion chamber. The stokehole cover can, for example, be plate-shaped and completely cover the stokehole. The stokehole cover can be a circular metal plate. A ring for sealing against an edge of the stokehole can be arranged in an outer edge region of the stokehole cover. The stokehole can thus be substantially sealed by the stokehole cover. The burner mouth and / or the insert assembly can be arranged or mounted on the side of the stokehole cover facing the combustion chamber.

[0019] The positioning device can be designed with a positioning mechanism by means of which the fuel line can be adjustable along a longitudinal axis of the burner mouth and relative to the burner mouth. The fuel line can then be adjusted within the burner mouth to ensure optimal fuel exit from the burner mouth into the combustion chamber. This optimizes fuel combustion with the burner. The positioning mechanism can, for example, be designed as a conical clamping sleeve that surrounds the fuel line and clamps it in the designated position. Alternatively, the positioning mechanism can be designed with a flange that clamps the burner mouth to the chimney cover.If the burner nozzle also has a flange, the flange of the burner nozzle can be clamped to the flange of the positioning device on the stokehole cover. This prevents potential stress cracks at the burner nozzle caused by differing thermal expansion between the burner nozzle and the stokehole cover. The burner nozzle can also be sealed to the stokehole cover.

[0020] The ceramic fiber composite can be formed from ceramic fibers and / or a ceramic matrix of aluminum oxide and / or zirconium oxide and / or silicon oxide and / or yttrium oxide. The ceramic fiber composite can have an open porosity of 10% to 70%, preferably 20% to 50%, and particularly preferably 30% to 40%. Furthermore, the ceramic fiber composite can have a fiber volume fraction of 10% to 70%, preferably 20% to 50%, and particularly preferably 30% to 40%.

[0021] The burner mouth can have a length of > 200 mm and / or a diameter or outer diameter of > 30 mm and / or a wall thickness of < 5 mm, preferably < 3 mm, particularly preferably < 2 mm.

[0022] The fuel can be a gas or an oil. Consequently, the fuel can be gaseous or liquid.

[0023] The furnace, kiln, anode kiln, tunnel kiln, or the like according to the invention comprises a burner according to the invention. Furthermore, the furnace can have a plurality of such burners. If the furnace is designed with stokeholes arranged in rows, the burners can also be arranged in rows at the stokeholes. The burners can be held or connected to a so-called burner ramp. This facilitates the offsetting of the burners from one row of stokeholes to the next.

[0024] In the inventive method for operating a burner on a furnace, kiln, anode kiln, tunnel kiln, or the like, the burner is arranged at a stoking hole of a combustion chamber of the furnace. A fluid fuel is supplied to a nozzle device of the burner via a fuel line. A burner mouth of the nozzle device is arranged in the stoking hole, and the fuel is introduced into the combustion chamber via the burner mouth. The burner mouth is formed from a ceramic fiber composite material. For the advantages of the inventive method, reference is made to the description of the advantages of the burner according to the invention.

[0025] Further advantageous embodiments of the method result from the feature descriptions of the dependent claims relating back to device claim 1.

[0026] A preferred embodiment of the invention is explained in more detail below with reference to the accompanying drawings.

[0027] They show:

[0028] Fig. 1 shows a longitudinal sectional view of a burner;

[0029] Fig. 2 is a detail view II from Fig. 1;

[0030] Fig. 3 is a detail view III from Fig. 1;

[0031] Fig. 4 shows a top view of the burner;

[0032] Fig. 5 shows a sectional view along a line VV from Fig. 1;

[0033] Fig. 6 shows a longitudinal sectional view of a burner mouth;

[0034] Fig. 7 shows a longitudinal sectional view of an insert element. A combined view of Figs. 1 to 7 shows a burner 10 for arrangement on a stokehole 11 of a furnace 12, which is only indicated here. The burner 10 has a fuel line 13, which is formed from a tube 14, and a nozzle assembly 15. A fluid fuel, such as a gas or oil, can be supplied to the nozzle assembly 15 via the fuel line 13. The nozzle assembly 15 has a burner opening 16, which here is formed from a tube section 17 with a flange 18 integrally formed thereon. The burner opening 16 consists of, or is formed from, a ceramic fiber composite material. A free end 19 of the fuel line 13 is formed with a nozzle insert 20 and opens inside the burner opening 16.

[0035] The burner 10 further comprises an insert 21 that completely coaxially surrounds the burner mouth 16 along its longitudinal extent. The insert 21 is formed from a cup-shaped insert element 22, which is also made of a ceramic fiber composite material. A perforation 24 is formed at a free end 23 of the insert element 22, with a pipe stub 25 being formed at the perforation 24 and projecting into an interior 26 of the insert element 22. In particular, it is also provided that the free end 23 of the insert element projects a short distance beyond the free end 19 of the burner mouth 16.

[0036] The hollow interior 26 of the insert element is filled with fiber material 27 of the insert device 21. An annular gap 28 is formed between the pipe stub 25 and the pipe section 17. The pipe section 17 is thus mechanically decoupled from the insert element and simultaneously thermally insulated from the furnace atmosphere of a combustion chamber 29 of the furnace 12. Furthermore, when inserting or removing the burner 10 from the stokehole 11, the burner mouth 16 cannot come into contact with or unintentionally strike a stokehole edge 30, thus preventing damage to the burner mouth 16 in the event of improper handling of the burner 10 by an operator.

[0037] The burner 10 further comprises a positioning device 31 which forms a stokehole cover 32. A round plate 33 of the stokehole cover 32 is designed such that it completely covers the stokehole 11, with a positioning ring 34 being attached to the plate 33, which rests sealingly against a support ring 35 of the stokehole 11.

[0038] Furthermore, the positioning device 31 has a positioning element 36, which is formed with a flange 37. The flange 37 is screwed to the plate 33 and clamps the flange 18 of the burner mouth 16 between the plate 33 and the flange 37. The flange 18 of the burner mouth 16 thus comes into a sealing contact with the plate 33 and also allows for easy replacement of the burner mouth 16. A conical clamping sleeve 38 in a clamping seat 39 and a nut 40 are also arranged on the flange 37. The clamping sleeve 38 surrounds the tube 14, so that by tightening and loosening the nut 40 the tube 14 can be fixed or moved in the direction of a longitudinal axis 41 or adjusted relative to the burner mouth 16.

Claims

March 10, 2026 INNOVATHERM G / IOT-020-WO Prof. Dr. Leisenberg GmbH + Co. KG Scu 35510 Butzbach Patent claims 1. Burner (10) for a furnace (12), kiln, anode kiln, tunnel kiln or the like, wherein the burner is designed for arrangement at a stoking hole (11) of a combustion chamber (29) of the furnace, wherein the burner has a fuel line (13) and a nozzle device (15), wherein fuel can be supplied to the nozzle device via the fuel line, wherein the nozzle device has a burner mouth (16) that can be arranged in the stoking hole, wherein the fuel can be introduced into the combustion chamber via the burner mouth, characterized by , that the burner mouth is made of a ceramic fiber composite material.

2. Burner according to claim 1 , characterized by , that a free end (19) of the fuel line (13) opens inside the burner mouth.

3. Burner according to claim 1 or 2, characterized by , that the burner mouth ( 16) is formed from a pipe section ( 17) with a flange ( 18) formed on it.

4. Burner according to one of the preceding claims, characterized by , that the burner ( 10) has an insert device (21 ) which at least partially, preferably completely, coaxially surrounds the burner mouth (16) along a longitudinal extent of the burner mouth.

5. Burner according to claim 4, characterized by , that the insert device (21) is flush with the burner mouth (16) or protrudes beyond the burner mouth.

6. Burner according to claim 4 or 5, characterized by , that, starting from a free end of the burner mouth ( 16), at least sectionally along the longitudinal extent of the burner mouth, an annular gap (28) is formed between the insert device (21 ) and the burner mouth.

7. Burner according to one of claims 4 to 6, characterized by , that the insert device (21 ) has a pot-shaped insert element (22) wherein an opening (24) for fuel discharge is formed at a free end (23) of the insert element.

8. Burner according to claim 7, characterized in that the insert element (22) is made of a ceramic fiber composite material.

9. Burner according to claim 7 or 8, characterized by , that the insert element (22) is at least partially, preferably completely, filled with a fiber material (27).

10. Burner according to one of claims 4 to 9, characterized by , that the burner ( 10) is designed with a positioning device (3 1 ) for arranging the nozzle device ( 15) in the stokehole ( 1 1 ), wherein the positioning device has a stokehole cover (32) that covers the stokehole, wherein the insert device (21) and / or the burner mouth ( 16) is arranged on the stokehole cover on a side of the stokehole cover facing the combustion chamber (29). 1 1. Burner according to claim 10, characterized by , that the positioning device (3 1 ) is designed with a positioning device (36) by means of which the fuel line (13) is adjustable along a longitudinal axis (41 ) of the burner mouth ( 16) and relative to the burner mouth.

12. Burner according to claim 1 1 , characterized by , that the positioning device (36) is designed with a flange (37) with which the burner mouth (16) is clamped to the stokehole cover (32).

13. Burner according to one of the preceding claims, characterized in that , that the ceramic fiber composite material is formed from ceramic fibers and / or a ceramic matrix of aluminum oxide and / or zirconium oxide and / or silicon oxide and / or yttrium oxide.

14. Burner according to one of the preceding claims, characterized by , that the burner mouth ( 16) has a length of > 200 mm and / or a diameter or outer diameter of > 30 mm and / or a wall thickness of < 5 mm, preferably < 3 mm, particularly preferably < 2 mm.

15. Burner according to one of the preceding claims, characterized by , that the fuel is a gas or an oil.

16. Furnace ( 12), kiln, anode kiln, tunnel kiln or the like, with a burner (10) according to any of the preceding claims.

17. Method for operating a burner (10) on a furnace (12), kiln, anode kiln, tunnel kiln or the like, wherein the burner is arranged at a stoking hole (11) of a combustion chamber (29) of the furnace, wherein fuel is supplied to a nozzle device (15) of the burner via a fuel line (13) of the burner, wherein a burner mouth (16) of the nozzle device is arranged in the stoking hole, and wherein the fuel is introduced into the combustion chamber via the burner mouth. characterized by , that the burner mouth is made of a ceramic fiber composite material.

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