Burner and method for operating same

Abstract

The invention relates to a burner (10) and to a method for operating a burner for a furnace, kiln, tunnel kiln or the like, wherein the burner comprises a first supply channel (11) for combustion air, a second supply channel (12) for a predominantly carbon-containing fuel gas, and a mixing unit (14) for mixing the combustion air with the fuel gas, wherein the mixing unit has a mixing chamber (16) which opens into a combustion chamber (21) of the burner, wherein a gas mixture of fuel gas and combustion air can be combusted within the combustion chamber, wherein the burner comprises a third supply channel (13) for a predominantly hydrogen-containing fuel gas, wherein the predominantly carbon-containing or the predominantly hydrogen-containing fuel gas can be selectively combusted by means of the burner.

Description

[0001] January 14, 2026

[0002] INNOVATHERM G / IOT-019-WO Prof. Dr. Leisenberg GmbH + Co. KG Scu / saa 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, tunnel kiln or the like, wherein the burner comprises a first supply channel for combustion air, a second supply channel for a predominantly carbon-containing fuel gas and a mixing unit for mixing the combustion air with the fuel gas, wherein the mixing unit has a mixing chamber which opens into a combustion chamber of the burner, wherein a gas mixture of fuel gas and combustion air is combustible within the combustion chamber.

[0005] Such burners are well-known and regularly used to introduce large quantities of heat energy into kilns or similar devices. For example, gas burners are used in the ceramics industry to operate kilns. The burner(s) are positioned on a kiln, and the hot gas outlet of the burner is directed into a combustion chamber of the kiln. Furthermore, these burners combust carbon-containing fuel gas, such as natural gas, as this is available in large quantities and at a relatively low cost via gas distribution networks.

[0006] Due to rising natural gas prices resulting from supply disruptions and CCL levies, as well as the need to switch to more climate-friendly fuel gases, there is an increasing demand to operate furnaces and burners with hydrogen-containing fuel gases. This can be achieved by replacing the burner(s) on a furnace that are designed to operate with, for example, natural gas, with burners designed to operate primarily with hydrogen-containing fuel gas.

[0007] A disadvantage here is that a continuous supply of hydrogen-containing fuel gas must be ensured. Discontinuous heating operation is often not possible due to specific production processes. Since it is expected that a sufficient quantity of hydrogen-containing fuel gas may not always be available when the energy sector switches from natural gas to hydrogen-containing fuel gases, the prices of different types of fuel gases are likely to fluctuate considerably. However, converting burners on a furnace is not easily done if, for example, one fuel gas or another is available at a particularly low price for a certain period.

[0008] The present invention is therefore based on the objective of proposing a burner and a method for operating a burner that allows for flexible use.

[0009] This problem is solved by a burner with the features of claim 1, a furnace with the features of claim 13, and a method with the features of claim 14. The burner according to the invention for a furnace, kiln, tunnel furnace, or the like comprises a first supply channel for combustion air, a second supply channel for a predominantly carbon-containing fuel gas, and a mixing unit for mixing the combustion air with the fuel gas, wherein the mixing unit has a mixing chamber that opens into a combustion chamber of the burner, wherein a gas mixture of fuel gas and combustion air is combustible within the combustion chamber, wherein the burner comprises a third supply channel for a predominantly hydrogen-containing fuel gas, wherein the predominantly carbon-containing or the predominantly hydrogen-containing fuel gas can be combusted by means of the burner.

[0010] The burner is designed to be supplied with predominantly hydrogen-containing fuel gas via the third feed channel, allowing this hydrogen-containing fuel gas to be combusted by the burner. Therefore, the burner is suitable for burning predominantly carbon-containing fuel gas and predominantly hydrogen-containing fuel gas, enabling the burner to switch between these two types of fuel gas depending on availability and price. This eliminates the need for any modifications to the burner, such as a complete burner replacement or the exchange of burner components like nozzles adapted to a specific fuel gas. The burner can thus be operated with both types of fuel gas without any further modifications.It is then also possible to switch between fuel gases without a lengthy conversion phase and without having to take a furnace out of service.

[0011] The first supply channel can open, at least partially, into the mixing chamber. This makes it possible to introduce combustion air directly into the mixing chamber and mix it with the fuel gas to create a combustible gas mixture. The combustion air can be drawn in from the surrounding environment, for example, by a fan, pump, or similar device, and conveyed to the mixing chamber through the first supply channel. Alternatively, a portion of the combustion air can be introduced directly into the combustion chamber, bypassing the mixing chamber. The first supply channel can then branch into the mixing chamber and the combustion chamber. A portion of the combustion air can then be mixed with the carbon-containing fuel gas in the mixing chamber, resulting in a flammable partial combustion with a flame. This flame is then sufficient to continue the ignition process in the combustion chamber with the remaining portion of the combustion air.Even with a high excess of air in the combustion chamber, the burner can be operated safely.

[0012] The first feed channel can coaxially surround the mixing chamber and be connected to it by a plurality of through-openings formed around the circumference of the mixing chamber. These through-openings can be bores equidistant from one another around the circumference of the mixing chamber. This allows combustion air, or a portion thereof, to be introduced into the mixing chamber and distributed evenly, thus promoting thorough mixing with the fuel gas. The through-openings can be inclined around the circumference of the mixing chamber, pointing towards the combustion chamber of the burner, thereby facilitating the flow of the gas mixture formed in the mixing chamber towards the combustion chamber.

[0013] The mixing unit can have a nozzle chamber that opens into the mixing chamber, with the second feed channel also opening into the nozzle chamber. The nozzle chamber can be designed such that it tapers towards the mixing chamber. When the second feed channel opens into the nozzle chamber, the predominantly carbon-containing fuel gas can flow into the nozzle chamber and be guided there, for example along a conical inner wall of the nozzle chamber, towards the mixing chamber. The nozzle chamber can be designed coaxially with the mixing chamber. The nozzle chamber can thus form a nozzle at one end opening into the mixing chamber.

[0014] The third feed channel can open into the mixing chamber adjacent to the combustion chamber or into the combustion chamber itself. The predominantly hydrogen-containing fuel gas can then be introduced almost directly into the combustion chamber via this third feed channel. This is advantageous because hydrogen-containing fuel gas can have a different flash point than methane-containing fuel gas. Since, for example, changing a nozzle is not possible during operation, the burner can only be operated with the respective fuel gases if these fuel gases are mixed with the combustion air at different points within the mixing unit to form a combustible gas mixture. In particular, the predominantly hydrogen-containing fuel gas can come into contact with the combustion air relatively closer to the combustion chamber.Otherwise, combustion of the predominantly hydrogen-containing fuel gas could shift into the mixing chamber, which would adversely affect burner performance and lead to long-term damage to the burner.

[0015] The third feed channel can be configured with a pipe extension that runs through the mixing chamber, with the mixing chamber coaxially surrounding the pipe extension. One end of the pipe extension, from which the predominantly hydrogen-containing fuel gas then exits, is located at one end of the mixing chamber, either at the combustion chamber or within the combustion chamber. The pipe extension can also be designed with variable length, for example, by means of an adjustable design. One end of the pipe extension can then be adapted to the composition of the predominantly hydrogen-containing fuel gas by shifting the pipe extension within the mixing unit. In particular, the pipe extension makes it possible to prevent combustion of the hydrogen-containing fuel gas within the mixing chamber, so that combustion takes place solely in the combustion chamber of the burner.

[0016] Butane, propane, methane, or natural gas, as well as a mixture thereof, can be used as the predominantly carbon-containing fuel gas, while hydrogen or ammonia can be used as the predominantly hydrogen-containing fuel gas. Predominantly carbon-containing fuel gas is defined as fuel gas with more than 50 mol percent carbon compounds, such as methane (CEU), and predominantly hydrogen-containing fuel gas is defined as fuel gas with more than 50 mol percent carbon-free hydrogen compounds, such as hydrogen (EL) or ammonia (NEE). Preferably, pure hydrogen gas or pure ammonia gas can be used. However, in principle, it is also possible to use a mixture of hydrogen and ammonia.

[0017] The burner can include at least one valve, preferably two valves, which allows fuel gas to be directed to the mixing unit via the second or third supply channel. The valve(s) can, for example, be solenoid valves. Fuel gas can then be metered into the mixing unit in the desired quantity via the valve. It is essential that the valve allows switching between the predominantly carbon-containing fuel gas and the predominantly hydrogen-containing fuel gas. The valve can therefore close off the second supply channel and open the third supply channel, or close off the third supply channel and open the second supply channel. For example, the valve can be a 3 / 2-way valve. Furthermore, a valve can be provided in each supply channel to perform a corresponding function.

[0018] The burner may include a control device configured to actuate the valve and supply the predominantly carbonaceous or predominantly hydrogen-containing fuel gas to the mixing unit. The control device may be a computer, a PLC, an electronic or electrical circuit, or the like, capable of supplying the burner with a specific type of fuel gas by actuating one or more valves.

[0019] The burner can have a detector device for detecting combustion in the combustion chamber, wherein the detector device may include an ionization electrode or a UV sensor. A flame in the combustion chamber can be detected by means of the detector device. The ionization electrode can be arranged on the mixing unit, for example, screwed into the mixing unit so that the ionization electrode protrudes into the combustion chamber. Alternatively, the UV sensor can be arranged on the combustion chamber or on the third feed channel, so that the UV sensor can detect the formation of a flame via UV radiation. The third feed channel can be used as a sighting tube for the UV sensor. Furthermore, a section of pipe can be arranged on, for example, the combustion chamber as a sighting tube for the UV sensor, on which the UV sensor is positioned in such a way that it does not come into direct contact with a flame.Furthermore, a window can also be formed on the combustion chamber, on which the UV sensor is located.

[0020] The burner may have an ignition device for igniting combustion in the combustion chamber, which may include an ignition electrode. The ignition electrode may be located directly adjacent to the mixing chamber or to a nozzle chamber of the mixing unit. An initial spark or ignition temperature can be generated via the ignition electrode, allowing ignition of a gas mixture in the mixing unit. It is advantageous if the ignition electrode is positioned at a distance from the combustion chamber so that it is not continuously exposed to high temperatures. The ignition electrode may be located at one end of the second feed channel. Fuel gas flowing out of the second feed channel can then also be used to cool the ignition electrode. Essential for igniting the burner with the ignition electrode or the ignition device is the formation of an ignitable gas mixture in the area of ​​the ignition electrode.Regardless of the location of the fuel gas exit at the mixing unit, a relatively slow flow of combustion air and fuel gas can form an ignitable gas mixture at the ignition electrode.

[0021] The furnace, kiln, tunnel kiln, or the like according to the invention comprises at least one burner according to the invention. Further advantageous embodiments of a burner are described in the features described in the dependent claims relating to claim 1.

[0022] In the inventive method for operating a burner on a furnace, kiln, tunnel kiln, or the like, the burner comprises a first supply channel for combustion air, a second supply channel for a predominantly carbon-containing fuel gas, and a mixing unit for mixing the combustion air with the fuel gas. The mixing unit has a mixing chamber that opens into a combustion chamber of the burner, in which a gas mixture of fuel gas and combustion air is combusted. The burner also comprises a third supply channel for a predominantly hydrogen-containing fuel gas, and the burner may selectively combust either the predominantly carbon-containing or the predominantly hydrogen-containing fuel gas. For the advantages of the inventive method, reference is made to the description of the advantages of the burner according to the invention.

[0023] Depending on the availability of predominantly carbon-based or predominantly hydrogen-based fuel gas, a burner control device can actuate at least one valve and supply either the predominantly carbon-based or predominantly hydrogen-based fuel gas to the mixing unit. This allows for a simple switch between the two fuel gas types during burner operation. A complete or prolonged shutdown of the furnace to change the fuel gas is then unnecessary. The control device can also be designed to automate the fuel gas switch. For example, the burner can primarily operate with predominantly hydrogen-based fuel gas, and in the event of a hydrogen shortage, the control device can switch the burner to operation with predominantly carbon-based fuel gas.This switchover can also be reversed if sufficient quantities of hydrogen-containing fuel gas are available.

[0024] Further advantageous embodiments of the method result from the feature descriptions of the dependent claims relating back to device claim 1.

[0025] The invention is explained in more detail below with reference to the accompanying drawings.

[0026] They show:

[0027] Fig. 1 shows a longitudinal sectional view of a burner;

[0028] Fig. 2 shows a section-by-section view of another burner.

[0029] Fig. 1 shows a longitudinal sectional view of a burner 10 for a furnace (not shown here). The burner 10 is configured with a first supply channel 11 for combustion air, a second supply channel 12 for a predominantly carbon-containing fuel gas, and a third supply channel 13 for a predominantly hydrogen-containing fuel gas. The burner 10 also includes a mixing unit 14, which is essentially formed by a one-piece metal burner body 15. The mixing unit 14 comprises a mixing chamber 16, a nozzle chamber 17, and an ignition chamber 18. Furthermore, the mixing unit 14 is connected to a tubular burner housing 19, which forms the first supply channel 11, and to a burner nozzle 20, which forms a combustion chamber 21.

[0030] It is essential that the first feed channel 11 opens into the mixing chamber 16. The second feed channel 12 opens into the ignition chamber 18 or nozzle chamber 17, and the third feed channel 13 opens into the combustion chamber 21. The third feed channel 13 is designed here with a pipe extension 22 that runs coaxially through the mixing chamber 16, the nozzle chamber 17, and the ignition chamber 18.

[0031] The burner 10 can be operated with methane or natural gas, or optionally with hydrogen or ammonia as fuel gas. The methane or natural gas is introduced via the second feed channel 12 into the nozzle chamber 17 and subsequently into the mixing chamber 16. Here, it mixes with combustion air, which enters the mixing chamber 16 through through-openings 23. The resulting gas mixture then combusts in the mixing chamber 16. Alternatively, the burner 10 can be operated with ammonia, in which case hydrogen or ammonia enters the combustion chamber 21 directly through the third feed channel 13. Combustion air flowing from the mixing chamber 16 mixes with the hydrogen or ammonia in the combustion chamber 21, followed by immediate combustion of this gas mixture in the combustion chamber 21.

[0032] Ignition of the respective gas mixture can be effected by means of an ignition electrode 24, which projects into the ignition chamber 18. During operation of the burner 10, a flame forms at a nozzle end 25 of the burner nozzle 20. The flame tips and hot gas from combustion in the combustion chamber 21 then develop at high velocity, causing circulation and turbulence within the furnace. Switching between the respective fuel gases is effected by controlling one or more valves (not shown here) that close or open at least the second supply channel 12 and the third supply channel 13.

[0033] Fig. 2 shows a sectional view of a burner 26 with a mixing unit 27, which is arranged in a tubular burner housing 28. The burner 26 further comprises a first supply channel 29 for combustion air, a second supply channel 30 for a predominantly carbon-containing fuel gas, and a third supply channel 31 for a predominantly hydrogen-containing fuel gas. The mixing unit 27 is formed by a one-piece metal burner body 32, within which a mixing chamber 33, a nozzle chamber 34, and an ignition chamber 35 are formed. Furthermore, through-openings 37 are formed on a circumference 36 of the mixing chamber 33, and a tubular extension 38 of the third supply channel 31 extends coaxially through the mixing chamber 33, the nozzle chamber 34, and the ignition chamber 35. Downstream of the mixing chamber 33 is a combustion chamber 39 of the burner 26. Furthermore, an ignition electrode 40 is arranged at the ignition chamber 35.Semicircular recesses 45 are formed on the circumference 43 of a lower collar 44 of the mixing chamber 33, through which combustion air from the first supply channel 11 is directed directly into the combustion chamber 21. This makes it possible to introduce a necessary quantity of combustion air into the combustion chamber 21 for complete combustion.

[0034] During operation of the burner 26, combustion air is supplied to the mixing unit 27 via the first supply channel 29 formed by the burner housing 28 and enters the mixing chamber 33 via the through-openings 37. Natural gas or methane, for example, is introduced into the ignition chamber 35 or the nozzle chamber 34 via the second supply channel 30. This fuel gas then enters the mixing chamber 33 via a nozzle 41 formed by the conically tapered nozzle chamber 34 and is mixed with the combustion air to form a combustible gas mixture. Following the mixing chamber 33, this gas mixture combusts in the combustion chamber 39.

[0035] Alternatively, the burner 26 can also be operated with hydrogen or ammonia as fuel gas. This fuel gas then enters the mixing unit 27 via the third supply channel 31, with one end 42 of the third supply channel 31 opening into the combustion chamber 39 outside the mixing chamber 33 and directly adjacent to it. Here, too, combustion air and the fuel gas mix, and combustion takes place in the combustion chamber 39. Because the pipe extension 38 opens into the combustion chamber 39 adjacent to it, combustion of hydrogen or ammonia within the mixing chamber 33 is prevented. This would occur if the predominantly hydrogen-containing fuel gas were introduced into the mixing unit 27 via the second supply channel 30.

Claims

January 14, 2026 INNOVATHERM G / IOT-019-WO Prof. Dr. Leisenberg GmbH + Co. KG Scu / saa 35510 Butzbach Patent claims 1. Burner (10, 26) for a furnace, kiln, tunnel kiln or the like, wherein the burner comprises a first supply channel (11, 29) for combustion air, a second supply channel (12, 30) for a predominantly carbonaceous fuel gas and a mixing unit (14, 27) for mixing the combustion air with the fuel gas, wherein the mixing unit has a mixing chamber (16, 33) which opens into a combustion chamber (21, 39) of the burner, wherein a gas mixture of fuel gas and combustion air is combustible within the combustion chamber, characterized by , that the burner includes a third feed channel ( 13 , 3 1 ) for a predominantly hydrogen-containing fuel gas, wherein the predominantly carbon-containing or the predominantly hydrogen-containing fuel gas can be combusted by means of the burner.

2. Burner according to claim 1 , characterized by , that the first feed channel (11, 29) opens at least partially into the mixing chamber (16, 33).

3. Burner according to claim 1 or 2, characterized by , that the first feed channel ( 1 1 , 29) coaxially surrounds the mixing chamber ( 16, 33) and is connected to the mixing chamber by a plurality of through-openings (23 , 37) formed over a circumference (36) of the mixing chamber.

4. Burner according to one of the preceding claims, characterized by , that the mixing unit (14, 27) has a nozzle chamber (17, 34) which opens into the mixing chamber (16, 33), with the second feed channel (12, 30) opening into the nozzle chamber.

5. Burner according to one of the preceding claims, characterized by , that the third feed channel ( 13 , 3 1 ) opens into the mixing chamber ( 16, 33) adjacent to the combustion chamber (21 , 39) or into the combustion chamber.

6. Burner according to one of the preceding claims, characterized by , that the third feed channel ( 13, 31 ) is formed with a pipe extension (22, 38) which runs through the mixing chamber (16, 33), the mixing chamber coaxially surrounding the pipe extension.

7. Burner according to one of the preceding claims, characterized by , that butane, propane, methane or natural gas and a mixture thereof can be used as the predominantly carbon-containing fuel gas, wherein hydrogen or ammonia can be used as the predominantly hydrogen-containing fuel gas.

8. Burner according to one of the preceding claims, characterized in that that the burner ( 10, 26) comprises at least one valve, preferably two valves, wherein fuel gas can be directed to the mixing unit ( 14, 27) via the second supply channel ( 12, 30) or the third supply channel ( 13 , 3 1) by means of the valve.

9. Burner according to claim 8, characterized by , that the burner ( 10, 26) includes a control device which is configured to actuate the valve and supply the predominantly carbon-containing or the predominantly hydrogen-containing fuel gas to the mixing unit ( 14, 27).

10. Burner according to one of the preceding claims, characterized by , that the burner ( 10, 26) has a detector device for detecting combustion in the combustion chamber (21 , 39), wherein the detector device has an ionization electrode or a UV sensor.

1. Burner according to one of the preceding claims, characterized by , that the burner ( 10, 26) has an ignition device for igniting a combustion in the combustion chamber (21 , 39), wherein the ignition device has an ignition electrode (24, 40).

12. Burner according to claim 1 1 , characterized by , that the ignition electrode (24, 40) is arranged at one end of the second feed channel (12, 30).

13. Furnace, kiln, tunnel kiln or the like, with at least one burner (10, 26) according to one of the preceding claims.

14. Method for operating a burner (10, 26) on a furnace, kiln, tunnel kiln or the like, wherein the burner comprises a first supply channel (11, 29) for combustion air, a second supply channel (12, 30) for a predominantly carbonaceous fuel gas and a mixing unit (14, 27) for mixing the combustion air with the fuel gas, wherein the mixing unit has a mixing chamber (16, 33) which opens into a combustion chamber (21, 39) of the burner, wherein a gas mixture of fuel gas and combustion air is burned within the combustion chamber, characterized by , that the burner includes a third feed channel (13, 31) for a predominantly hydrogen-containing fuel gas, wherein the predominantly carbon-containing or the predominantly hydrogen-containing fuel gas is selectively burned by means of the burner.

15. Method according to claim 14, characterized by , that a control device of the burner (10, 26) actuates at least one valve depending on the availability of predominantly carbon-containing or predominantly hydrogen-containing fuel gas and supplies the predominantly carbon-containing or the predominantly hydrogen-containing fuel gas to the mixing unit (14, 27).

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