ROTATING REGENERATION BURNER

Description

[0001] The invention relates to a burner for a fuel combustion system, comprising at least one fuel supply for the supply of fuel, at least one combustion air supply for the supply of combustion air, at least one exhaust gas recirculation for the recirculation of exhaust gas, and at least one combustion element for the combustion of supplied fuel in combustion air while obtaining exhaust gas.

[0002] Such a burner is known, for example, from WO 2016 / 070977 A1. This burner is used in regenerative combustion systems with a number of other burners, each comprising a bidirectionally operable pipe section, operating alternately in a first and a second operating mode. In the first operating mode, fuel is combusted in a combustion chamber with combustion air supplied via the bidirectionally operable pipe section, producing exhaust gas. In the second operating mode, the exhaust gas is discharged from the combustion chamber via the bidirectionally operable pipe section. Such regenerative combustion systems enable combustion with energy recovery. These systems comprise a number of regenerative burners that operate alternately in a first and a second operating mode.In the first group of regenerative burners, operating in the first mode, combustion takes place in a combustion chamber. Fuel is burned in the combustion chamber with the addition of combustion air. Simultaneously, in a second group of regenerative burners, operating in the second mode, exhaust gas from this combustion is discharged from the combustion chamber. Typically, each regenerative burner has a common supply and return line for combustion air and exhaust gas, respectively, in the form of a bidirectional section of a gas line. Depending on the operating mode, either combustion air can be supplied to the respective regenerative burner via this bidirectional section, or exhaust gas can be discharged. The fuel is supplied via one or more separate lines.After switching from the second to the first operating mode, a purge phase is usually performed at the beginning of the first operating mode. During this purge phase, any residual exhaust gas remaining in the respective bidirectionally operated pipe section after the second operating mode is removed. This can be done, for example, by flushing the pipe section with air. During this purge phase, the corresponding regenerative burner usually cannot be used for combustion. Only when the residual exhaust gas has been completely removed from the bidirectionally operated pipe section is combustion air supplied again via this section, and the corresponding regenerative burner is then fired with fuel. This process is time-consuming and leads to inconsistencies in the heat output of the regenerative burner system.Furthermore, energy recovery from such regenerative burner systems always requires several burners that are operated alternately in the two operating modes, which therefore leads to high plant costs and delays amortization through the reduction of energy costs via energy recovery.

[0003] Furthermore, JP S64 75815 A discloses a burner that cyclically alternates between at least a first and a second configuration, wherein in the first configuration the combustion air supply passes through a first subsection of a heat exchanger, wherein the first subsection transfers heat absorbed therein to the supplied combustion air, and the exhaust gas recirculation passes through a second subsection of the heat exchanger, wherein the second subsection absorbs heat from the exhaust gas, wherein in the second configuration the combustion air supply passes through the second subsection of the heat exchanger, wherein the second subsection transfers heat absorbed therein to the supplied combustion air, and the exhaust gas recirculation passes through the first subsection of the heat exchanger, wherein the first subsection absorbs heat from the exhaust gas.

[0004] Furthermore, US 5,848,885 A and US 5,628,629 A disclose burners, each comprising a rotor, the rotor being designed to guide the combustion air through the first section of the heat exchanger and the exhaust gas through the second section of the heat exchanger in the first rotation position associated with the first configuration, and to guide the combustion air through the second section of the heat exchanger and the exhaust gas through the first section of the heat exchanger in the second rotation position associated with the second configuration.

[0005] JP H07 55132 A also discloses a burner in which the cyclical change between configurations takes place continuously, whereby the sections of the heat exchanger that serve to heat the combustion air and to cool the exhaust gases are constantly and continuously changed by the rotation of the rotor.

[0006] A particular disadvantage of the described burners is that the service life of the drive is reduced by wear and tear, and the drive and the rotor bearing are not adequately cooled.

[0007] The object of the invention is therefore to provide an improved burner that offers effective energy recovery at low plant costs and enables homogeneous heat output.

[0008] This problem is solved by a burner having the features of claim 1.

[0009] The invention provides a burner that offers effective energy recovery via the heat exchanger, with the cyclical switching ensuring a consistent heat output. Furthermore, the system costs for such a burner are relatively low, as no additional, alternately operated burner is required for energy recovery. Because the burner switches between the first and second configurations, the burner's heat exchanger can operate differently in each configuration. The section of the heat exchanger that supplies combustion air in the first configuration can thus become part of the exhaust gas recirculation system in the second configuration. This allows the same section, which absorbed heat in the first configuration, to transfer heat to the combustion air, while in the second configuration it absorbs heat from the exhaust gas.By having the burner's heat exchanger comprise several sections that cyclically serve to heat the combustion air and cool the exhaust gas, the burner can be operated continuously and energy can be recovered continuously. This enables a consistent heat output from the burner. According to the invention, the burner's cyclical switching between configurations occurs continuously, so that the heat output generated by the burner is homogeneous over time.

[0010] According to the invention, the burner comprises a rotor which is designed to effect the change between the first and the second configuration.With such a rotor, the sections of the heat exchanger can be switched between combustion air supply and exhaust gas recirculation, so that the same sections of the same heat exchanger can be used cyclically to heat the combustion air and to cool the exhaust gas, thus enabling simple but effective energy recovery. The rotor is designed to, in the first rotation position assigned to the first configuration, guide the combustion air through the first section of the heat exchanger and the exhaust gas through the second section of the heat exchanger, and in the second rotation position assigned to the second configuration, guide the combustion air through the second section of the heat exchanger and the exhaust gas through the first section of the heat exchanger.The rotor enables a particularly smooth and continuous changeover between configurations, as the simple and continuous rotation allows the heat exchanger sections to be used cyclically for heating the combustion air and cooling the exhaust gas, depending on the rotor's position. The rotation speed also allows for easy control over how long a specific section absorbs heat from the exhaust gas and how long, after switching configurations, it is used to transfer heat to the incoming combustion air. Depending on the rotor's rotational position, a specific section of the heat exchanger is used either for heating the combustion air, cooling the exhaust gas, or for regeneration. The rotor is preferably mounted on sliding bushings, which are suitable for use even at higher temperatures up to approximately 250 °C.The rotor is preferably designed so that its center of mass lies in the axis of rotation, thus avoiding imbalance and one-sided weight loading.

[0011] According to the invention, the exhaust gas recirculation is formed at least partially by an exhaust gas housing, and the combustion air supply is formed at least partially by an air housing. The rotor separates the combustion air supply formed in the air housing from the exhaust gas recirculation formed in the exhaust gas housing. By separating the combustion air supply from the exhaust gas recirculation via the rotor, the sections of the heat exchanger can be alternately connected to the air housing and the exhaust gas housing in the cyclically traversed configurations, allowing the sections to be used for both combustion air supply and exhaust gas recirculation. This enables the combustion air to be easily introduced from the air housing into the heat exchanger section that serves for combustion air supply.The discharge of exhaust gases from the combustion process is also very simple via the heat exchanger section, which serves for exhaust gas recirculation. The rotor is preferably fluidically separated from the exhaust gas housing by a shaft seal in the air housing.

[0012] Furthermore, according to the invention, the rotor is driven within the air housing by a chain drive. In this way, the drive motor is located far enough away from the hot area of ​​the rotor to achieve a long service life of the drive and minimize wear. In addition, the invention provides that the chain drive and a central bearing for the rotor are cooled by the combustion air blown into the air housing.

[0013] Advantageous embodiments and further developments of the invention are described in the dependent claims. It should be noted that the features listed individually in the claims can also be combined in any technologically meaningful way, thus revealing further embodiments of the invention.

[0014] A particularly advantageous embodiment of the invention relates to the fact that the fuel element is designed to rotate with the rotor, wherein, through the rotation of the fuel element, at least one fuel outlet opening is directed towards the preheated combustion air exiting the heat exchanger. The rotation of the fuel element together with the rotor provides a simple way to align the fuel outlet opening towards the combustion air exiting the heat exchanger, which has been preheated by the heat exchanger, thus ensuring efficient combustion of the supplied fuel in the burner. By aligning the fuel outlet opening towards the section of the heat exchanger used for preheating the combustion air, the combustion air and the fuel can be effectively mixed for combustion.The fuel outlet through the fuel outlet opening can always point in the direction of the combustion air outlet. The fuel element is preferably rotatably connected to the burner housing via a gas swivel joint. The fuel outlet opening is preferably designed as a gas outlet nozzle directed towards the heat exchanger. The rotational movement of the fuel element is preferably achieved via a drive element that is positively connected to the rotor. In this way, the rotor simply transmits the rotational movement to the fuel element. Thus, the rotor and fuel element always rotate at the same speed. This ensures that the fuel outlet opening is always aligned with the section of the heat exchanger from which the preheated combustion air exits. Furthermore, incorrect installation of the fuel element can be prevented by a preferably asymmetrical arrangement of the drive element.This allows assembly errors during maintenance and repairs to be avoided through design.

[0015] According to an advantageous embodiment of the invention, it is provided that an exhaust pipe is attached eccentrically to the exhaust housing.

[0016] A particularly advantageous embodiment of the invention relates to the exhaust housing having an annular channel attached to its circumference. This annular channel minimizes flow-induced pressure fluctuations to the exhaust pipe.

[0017] A particularly advantageous embodiment provides that the rotor runs within the exhaust housing and is separated from the heat exchanger at its end face by a replaceable fan-shaped disc. The fan-shaped disc prevents frictional wear on the heat exchanger, as the rotor may only contact the disc.

[0018] According to an advantageous embodiment of the invention, it is provided that the combustion air is blown eccentrically into the air housing.

[0019] An advantageous embodiment of the invention provides that the heat exchanger is cylindrical and arranged coaxially to the fuel element. With the cylindrical design of the heat exchanger and its coaxial arrangement to the fuel element, the sections of the heat exchanger can be easily switched or configured cyclically between different configurations. In this way, the sections of the heat exchanger arranged coaxially to the fuel element can effectively supply the fuel element with combustion air in one configuration and effectively discharge the exhaust gases produced by combustion via the heat exchanger in the other configuration. The sections of the heat exchanger are preferably formed by circular sectors of the cylindrical heat exchanger.With the coaxial arrangement around the fuel element, individual circular sectors of the heat exchanger can be used in one configuration for combustion air supply, while other circular sectors in this configuration are used for exhaust gas recirculation. The rotation of the fuel element together with the rotor preferably allows the circular sector-shaped sections of the heat exchanger to be cyclically changed by simple rotation. With the continuously rotating rotor, a first circular sector-shaped section of the heat exchanger, which, according to the invention, releases previously stored heat to the combustion air, and a second circular sector-shaped section, which is heated by the exhaust gas, can be assigned to virtually any angular position of the rotor, with these sections exchanging their heat transfer and heat absorption functions after each 180° rotation.

[0020] A particularly advantageous embodiment features a fuel element designed as a lance, with the lance protruding through a lance opening provided in the heat exchanger. This lance-shaped design allows the fuel element's outlet to be positioned close to the outlet surface of the section of the heat exchanger that serves as the combustion air supply. This enables effective heating of the combustion air by the heat recovered from the exhaust gas via the heat exchanger. The lance-shaped fuel element can be designed for various fuel media, with a lance specifically designed for each fuel being installed in the burner. Preferably, the fuel element should be capable of burning various gas types, such as natural gas H, natural gas L, and LPG.The lance preferably contains an ignition electrode, which is screwed into the lance in such a way that it does not rotate. The ignition electrode serves to ignite the mixture of combustion air and fuel at the fuel outlet opening in the furnace.

[0021] An advantageous embodiment provides that the heat exchanger has a honeycomb structure, wherein the honeycomb structure forms guide channels designed to direct the combustion air and / or exhaust gas. The combustion air and exhaust gas can be used section by section through the heat exchanger for combustion air supply and exhaust gas recirculation via the guide channels formed in the honeycomb structure. Adjacent guide channels within the honeycomb structure are grouped by the rotor into subsections that are connected in the same configuration. Thus, adjacent guide channels within the honeycomb structure together form a subsection, with the rotor dividing the honeycomb-structured heat exchanger into several subsections, each consisting of adjacent guide channels. The honeycomb structure is preferably made of a ceramic material.

[0022] According to a preferred embodiment of the invention, the honeycomb structure is embedded in a monolithic frame. The monolithic frame allows for easy placement of the honeycomb structure (e.g., in the wall of an oven).

[0023] A particularly advantageous embodiment involves connecting the heat exchanger to the furnace housing via a flange. The flange allows for easy installation of the burner's heat exchanger within the furnace housing.

[0024] A particularly advantageous embodiment of the invention provides that the heat exchanger has a channel, wherein a UV photocell arranged outside the heat exchanger monitors the flame temperature during combustion via the channel. Such a photocell enables the monitoring of the combustion flame. The flame can be monitored up to an operating temperature of the combustion chamber of 850 °C, after which the monitoring is switched off in accordance with regulations.

[0025] Further features, details, and advantages of the invention will become apparent from the following description and from the drawings, which show exemplary embodiments of the invention. Corresponding objects or elements are provided with the same reference numerals in all figures. The figures show: Figure 1: Burner according to the invention in sectional view; Figure 2: Burner in further sectional view; Figure 3: Burner in side sectional view; Figure 4: Heat exchanger in furnace wall; Figure 5: Burning element; Figure 6: Air housing; Figure 7: Rotor and Figure 8: Exhaust housing.

[0026] In the Figure 1Reference numeral 1 shows a burner according to the invention. The burner 1 for fuel combustion has a fuel supply 2, which serves to supply fuel 3, shown as a block arrow, for combustion. The burner 2 also has a combustion air supply 4, through which combustion air 5, also indicated as a block arrow, is supplied to assist combustion. Furthermore, the burner 1 includes a combustion element 8, which serves to combust fuel 3 with combustion air 5, producing exhaust gas 7, shown as a block arrow. The burner 1 shown here is characterized in particular by the fact that it cyclically switches between at least two configurations. In the first of the two configurations, the combustion air supply 4 passes through a first section A of a heat exchanger 9, wherein the first section A transfers the heat absorbed therein to the supplied combustion air 5.In this first configuration of the burner 1, the exhaust gas recirculation 6 passes through a second section B of the heat exchanger 9, whereby the second section B absorbs heat from the exhaust gas 7 and regenerates itself. In the second of the two configurations, the combustion air supply 4 is formed by the second section B of the heat exchanger 9, whereby the second section B then transfers the heat absorbed in the first configuration to the supplied combustion air 5. In this second configuration, the exhaust gas recirculation 6 is formed by the first section A of the heat exchanger 9, whereby the first section A absorbs heat from the exhaust gas 7 and regenerates itself. Through the cyclical switching between the two described configurations, a single heat exchanger 9 can be used simultaneously, section by section, for both heating the combustion air 5 and for regeneration from the heat of the exhaust gas 7.This allows the fuel element 8 of the burner 1 shown to be used continuously, and combustion does not need to be interrupted for regeneration of the heat exchanger 9 or carried out by another burner. This makes it possible to manufacture a burner 1 that offers a homogeneous heat output and whose manufacturing costs are low compared to known regenerative burner systems. To enable switching between configurations, the burner has a rotor 10. The rotor 10 rotates continuously at a substantially constant angular velocity during the combustion of the fuel 3. In the first rotation position of the rotor 10, the burner 1 is in the first configuration. In this position, the rotor 10 directs the combustion air 5 through the first section A of the heat exchanger 9, and the exhaust gas 7 is directed through a second section B of the heat exchanger 9.In a second rotational position around the axis of rotation of the rotor 10, different from the first, the burner 1 is switched to a second configuration in which the combustion air 5 is guided through the second section B of the heat exchanger 9 and the exhaust gas 7 is guided through the first section A of the heat exchanger 9. The continuous rotation of the rotor 10 effectively switches between any number of overlapping configurations of the burner 1, in each of which corresponding and overlapping sections of the heat exchanger 9 serve to heat the combustion air 5 or to cool the exhaust gas 7 and to regenerate the heat exchanger 9.Due to the cylindrical design of the heat exchanger 9, which is coaxial with the fuel element 8, the entire surface of the heat exchanger 9 can be used section by section for heating the combustion air 5 and cooling the exhaust gas 7, with the sections A and B being formed by sectors of the total surface of the heat exchanger 9. The rotor 10 can also be configured such that several sectors are used simultaneously for heating the combustion air 5 and several sectors for cooling the exhaust gas 7. In this case, the fuel element 8 must be provided with additional fuel outlet openings 11. The fuel element 8 rotates with the rotor 10 such that, due to the rotation of the fuel element 8, at least one fuel outlet opening 11 is directed towards the preheated combustion air 5 exiting the heat exchanger 9.The fuel outlet can always point in the combustion air outlet direction through the rotating fuel outlet opening 11. As can be further seen, the fuel element 8 is designed as a lance and protrudes through the heat exchanger 9. For this purpose, a lance passage 12 is provided in the heat exchanger 9. The heat exchanger 9 is formed by a honeycomb structure 13, which is preferably made of ceramic. This honeycomb structure 13 forms guide channels 14, which serve to guide the combustion air 5 or the exhaust gas 7 through the heat exchanger 9. The honeycomb structure 13 is preferably embedded in a monolithic frame 15. The heat exchanger 9 is connected to the furnace housing 17, which belongs to the furnace fired by the burner 1, via a flange 16. Figure 1Also visible is a channel 18 that extends through the heat exchanger 9. This channel 18 is designed to monitor the flame temperature during combustion via a UV photocell 19 located outside the heat exchanger 9. The exhaust gas recirculation 6 of the burner 1 is formed by an exhaust gas housing 20, which includes a connection 22 for the exhaust gas discharge line. The combustion air supply 4 is formed, at least partially, by an air housing 21, which has a connection 23 for the supply air line. The rotor 10 separates the combustion air supply 4 formed in the air housing 21 from the exhaust gas recirculation 6 formed in the exhaust housing 20.By separating the combustion air supply 4 from the exhaust gas recirculation 6 via the rotor 10, the sections A and B of the heat exchanger 9 can be alternately connected to the air housing 21 and the exhaust gas housing 20 in cyclically changing configurations, thus using the sector-shaped sections A and B for the combustion air supply 4 and the exhaust gas recirculation 6, respectively. This allows for the simple introduction of combustion air 5 via the air housing 21 into the heat exchanger section serving the combustion air supply 4. The exhaust gases 7 from the combustion process are easily discharged via the heat exchanger section serving the exhaust gas recirculation 6, allowing for simple heat regeneration and exhaust gas discharge 7 via the exhaust gas housing 20. The rotor 10 is fluidically separated from the exhaust gas housing 20 by a shaft seal within the air housing 21. Figure 1Further visible is the drive 24, preferably arranged on the air housing 21, for the rotational movement of the fuel element 8 and the rotor 10. Preferably, a spur geared motor is provided for the drive 24 of the rotor 10, preferably with a drive power of 0.12 kW. Its speed can preferably be controlled via a frequency converter. In this way, the rotation of the fuel element 8 and the rotor 10, and the associated heat exchange in the honeycomb structure of the heat exchanger 9, can be varied. The burner 1 can thus be optimally adapted to the process in the furnace by adjusting the rotational speed. The spur geared motor is arranged outside the burner housing and drives a chain drive 25 located inside the air housing 21. In this way, the drive motor 24 is located far enough away from the hot area of ​​the rotor 10 to ensure a long service life for the drive 24 and minimize wear.Within the air housing 21, the rotor 10 is driven by the chain drive 25. This design allows for the easy accommodation and compensation of different linear and thermal expansions at varying operating temperatures of the burner 1. Furthermore, the chain drive 25 provides thermal decoupling of the rotor 10 from the geared motor 24. The chain drive 25 is located within the air housing 21 because this significantly minimizes the risk of accidents caused by rotating components and also ensures cooling of the chain drive 25 by the supplied combustion air 5.

[0027] In Figure 2 The partially cutaway burner 1 is shown according to Figure 1Shown from a different perspective. Here, the arrangement of the rotor 10 on the lance-shaped fuel element 8 is more clearly visible. The rotor 10 has a passage 26 that leads from the air housing 21 to the heat exchanger 9 and forms the circular sector that encompasses the section of the heat exchanger 9 for the combustion air supply 4. Furthermore, this illustration clearly shows how the rotor 10 separates the combustion air supply 4 formed in the air housing 21 from the exhaust gas recirculation 6 formed in the exhaust gas housing 20. For this purpose, the rotor 10 has a chamber 27 that is decoupled from the passage 26. Also clearly visible in this illustration is the channel 18 formed in the heat exchanger 9, through which the UV photocell 19 monitors the flame temperature of the burner 1.

[0028] The Figure 3 shows burner 1 according to Figure 1 and 2in a cross-sectional view through the axis of rotation of the fuel element 8. In this illustration, the chain drive 25, arranged in the air housing 21, for transmitting the drive power from the drive 24 to the rotor 10 and the fuel element 8, is clearly visible. The guide channels 14 formed in the heat exchanger 9, which extend along the lance-shaped fuel element 8 in the honeycomb-structured heat exchanger 9, are also visible. Figure 3 The honeycomb structure 13 of the heat exchanger 9 extends around the lance passage 12, through which the fuel element 8 is guided. A monolithic frame 15 is formed around the honeycomb structure 13 of the heat exchanger 9, to which a flange 16 is arranged, connecting the heat exchanger 9 to the furnace housing 17.

[0029] Out of Figure 4A single view of the heat exchanger 9 is shown, which is arranged here as an example in a section of the furnace wall 17. The heat exchanger 9 is attached to the furnace wall 17 via the flange 16. The honeycomb structure 13 within the monolithic frame 15 is also clearly visible and is interrupted in the middle by the lance passage 12 formed here. The honeycomb structure 13 of the heat exchanger 9 is made of a highly heat-resistant ceramic.

[0030] With Figure 5 A close-up view of the fuel element 8 is shown. It can also be seen that the fuel outlet opening 11 is located at the end of the lance-shaped fuel element 8. At the opposite end, the drive mechanism is provided, via which the fuel element 8 is driven by the chain drive 25 of the drive 24. The gas lance 8 and the igniter can be easily installed and removed via the flange 28 provided on the fuel element 8 from the front face of the air housing 21.

[0031] Out of Figure 6 A detailed view of the air housing 21 is shown. A combustion air duct, preferably with a diameter of 8 cm, is preferably connected to the air housing 21. The combustion air 5 is preferably supplied as shown in the figure. Figure 6The combustion air 5 is blown eccentrically into the housing 21. A central pin 29 for the bearing of the rotor 10 is also visible in the center of the air housing 21. The chain drive 25 and the bearing 29 of the rotor 10, both located in the housing 21, are cooled by the combustion air 5 blown into the air housing 21. Forces exerted by the rotor 10, which can occur due to temperature-dependent thermal expansion, are absorbed by spring-loaded pressure pieces in the end face of the air housing. These pressure pieces prevent the rotor 10 of the burner 1 from jamming, even in the event of overheating. Preferably, the pressure forces are adjustable and can be adapted to the operating conditions.

[0032] With Figure 7The core component of burner 1, namely the rotor 10, is shown in a close-up view. This illustration clearly shows how the passage 26 for the combustion air 5 is separated from the chamber 27 for the exhaust gases 7. This separates the combustion air side from the exhaust gas side within burner 1. The active sections A and B of the heat exchanger 9 are defined by the configuration of the passage 26 and the chamber 27, as well as the position of the rotor 10. The rotation of the rotor 10 continuously and seamlessly transitions between sections A and B of the heat exchanger 9, which serve to heat the combustion air 5 and cool the exhaust gases 7. The rotor 10 shown here is designed so that its center of mass lies on the axis of rotation, thus preventing imbalance and uneven weight distribution during rotation.

[0033] In the representation according to Figure 8The exhaust housing 20 is shown separately. The exhaust housing 20 is connected to an exhaust pipe, which preferably has a diameter of 10 cm. Preferably, the exhaust pipe is attached eccentrically to the exhaust housing 20, as shown in Figure 8 The rotor 10 runs within the exhaust housing 20 and is separated from the heat exchanger 9 at its end face by a replaceable fan disc 30. The fan disc 30 prevents frictional wear on the heat exchanger 9, as the rotor 10 may only contact the fan disc 30. To minimize pressure pulsations in the exhaust pipe caused by the rotor 10, the exhaust housing 20 has an additional annular channel 31 attached to its circumference. This annular channel 31 minimizes flow-induced pressure fluctuations to the exhaust pipe.

[0034] For cleaning the burner 1, a pressure port is provided on the air housing 21, through which the housing 21 can be pressurized with compressed air up to 6 bar. This allows scale residues and dust accumulation in the guide channels 14 of the honeycomb structure 13 of the heat exchanger 9 to be blown into the furnace chamber by the increased pressure. This allows the efficiency of the heat exchanger 9 to be kept almost constant over a longer period. The cleaning cycle and cleaning duration must be determined according to the operating conditions in the furnace.

[0035] The burner 1 described here is intended to replace cold air burners in high-temperature continuous furnaces in the steel industry. These burners typically have a power output between 100 kW and 1.2 MW. The proposed burner 1 can be scaled up or down to any desired power output, making it highly scalable and flexible in its power setting. Preferably, the burner 1 should also be power-regulated within its power range. The control range can be up to 1:7, with a stable control range of at least 1:3 being desirable. All components of the burner 1 can be easily disassembled with just a few tools, making maintenance very simple.

[0036] A key advantage of the described burner is that it can be exchanged for existing cold air burners where the use of energy-saving regenerative burners is otherwise not possible due to structural limitations. Reference symbol list

[0037] 1 Burner 2 Fuel supply 3 Fuel 4 Combustion air supply 5 Combustion air 6 Exhaust gas recirculation 7 Exhaust gas 8 Fuel element 9 Heat exchanger 10 Rotor 11 Fuel outlet 12 Lance passage 13 Honeycomb structure 14 Guide channels 15 Frame 16 Flange 17 Furnace housing 18 Channel 19 UV photocell 20 Exhaust gas housing 21 Air housing 22 Connection for exhaust gas discharge duct 23 Connection for intake air duct 24 Drive 25 Chain drive 26 Feedthrough 27 Chamber 28 Fuel element flange 29 Central pin 30 Fan disc 31 Annular channel First section (heat exchanger) Second section (heat exchanger)

Claims

1. Burner (1) for a fuel combustion, having - at least one heat exchanger (9), - at least one fuel supply (2) for supplying fuel (3), - at least one combustion air supply (4) for supplying combustion air (5), - at least one exhaust gas recirculation (6) for recirculating exhaust gas (7), and - at least one combustion element (8) for burning supplied fuel (3) with combustion air (5) to produce exhaust gas (7), wherein the burner cyclically switches between at least a first and a second configuration, wherein in the first configuration, the combustion air supply (4) flows through a first section (A) of the heat exchanger (9), wherein the first section (A) transfers heat absorbed therein to the supplied combustion air (5), and the exhaust gas recirculation (6) flows through a second section (B) of the heat exchanger (9), wherein the second section (B) absorbs heat from the exhaust gas (7), in the second configuration, the combustion air supply (4) flows through the second section (B) of the heat exchanger (9), wherein the second section (B) transfers heat absorbed therein to the supplied combustion air (5), and the exhaust gas recirculation (6) flows through the first section (A) of the heat exchanger (9), wherein the first section (A) absorbs heat from the exhaust gas (7), wherein the burner (1) comprises a rotor (10), wherein the rotor (10) is configured to direct, in a first rotational position associated with the first configuration, the combustion air (5) through the first section (A) of the heat exchanger (9) and the exhaust gas (7) through the second section (B) of the heat exchanger (9), and, in a second rotational position associated with the second configuration, to direct the combustion air (5) through the second section (B) of the heat exchanger (9) and the exhaust gas (7) through the first section (A) of the heat exchanger (9), wherein the exhaust gas recirculation (6) is formed, at least in sections, by an exhaust gas housing (20), wherein the combustion air supply (4) is formed, at least in sections, by an air housing (21), wherein the rotor (10) separates the combustion air supply formed in the air housing from the exhaust gas recirculation formed in the exhaust gas housing, characterized in that the rotor (10) is driven within the air housing (21) by a chain drive (25), wherein the chain drive (25) provided in the air housing (21) and a central pin (29) for a bearing (29) of the rotor (10) are cooled by the combustion air (5) blown into the air housing (21).

2. Burner (1) according to claim 1, characterized in that the rotor (10) rotates continuously at a substantially constant angular velocity.

3. Burner (1) according to any one of the preceding claims, characterized in that the combustion element (8) is designed to rotate with the rotor (10), whereby, due to the rotation of the combustion element (8), at least one fuel outlet opening (11) is directed toward the preheated combustion air (5) exiting the heat exchanger (9).

4. Burner (1) according to any one of the preceding claims, characterized in that an exhaust gas line is mounted eccentrically on the exhaust gas housing (20).

5. Burner (1) according to any one of the preceding claims, characterized in that the exhaust housing (20) comprises an annular channel (31) mounted at the circumference designed to minimize flow-induced pressure fluctuations in the exhaust pipe.

6. Burner (1) according to any one of the preceding claims, characterized in that the rotor (10) rotates within the exhaust housing (20) and is separated from the heat exchanger (9) at the end face by a replaceable fan-type disc (30).

7. Burner (1) according to any one of the preceding claims, characterized in that the combustion air (5) is blown eccentrically into the air housing.

8. Burner (1) according to any one of claims 1 through 7, characterized in that the heat exchanger (9) is cylindrical in shape and is arranged coaxially with the combustion element (8).

9. Burner (1) according to any one of claims 1 through 8, characterized in that the combustion element (8) is designed as a lance, wherein the lance (8) extends through a lance passage (12) provided in the heat exchanger (9).

10. Burner (1) according to any one of claims 1 through 9, characterized in that the heat exchanger (9) has a honeycomb structure (13), wherein the honeycomb structure (13) forms guide channels (14) that are configured to guide the combustion air (5) and the exhaust gas (7), respectively.

11. Burner (1) according to claim 10, characterized in that the honeycomb structure (13) is embedded in concrete within a monolithic frame (15).

12. Burner (1) according to any one of claims 1 through 11, characterized in that the heat exchanger (13) is connected to a furnace housing (17) via a flange (16).

13. Burner (1) according to any one of claims 1 through 12, characterized in that the heat exchanger (9) comprises a channel (18), wherein a UV photocell (19) arranged outside the heat exchanger (9) monitors the flame temperature during combustion via the channel (18).