PROCESS FOR CONVERSING AN INDUSTRIAL FURNACE BURNER TO HYDROGEN

Abstract

A method for converting a burner (1) positioned on a wall (3) of an industrial furnace (2), said burner being supplied with carbonaceous fuel and oxidizer through conduits (4, 5) internal to the burner, characterized in that it comprises the addition of at least one hydrogen injection lance (6), or a hydrogen-rich gas, passing through the furnace wall and opening into it in the vicinity of the burner, so that the burner is capable of using, at least partially, the hydrogen or hydrogen-rich gas supplied by the injection lance(s) as fuel. Figure for the abstract: 4

Description

Title of the invention: METHOD FOR CONVERTING AN INDUSTRIAL FURNACE BURNER TO HYDROGEN Designation of the technical field concerned

[0001] The invention relates to industrial furnaces for heating metal products equipped with burners, in particular preheating furnaces before rolling. Technical problems that the invention addresses

[0002] Reheating furnaces play a crucial role in the steelmaking process, where steel products are heated to high temperatures for subsequent operations, for example rolling in hot rolling mills.

[0003] However, these ovens contribute significantly to emissions of carbon dioxide (CO2) and nitrogen oxide (NOx), which must be reduced with stricter regulations.

[0004] Today, most reheating furnace modernization projects aim to reduce the carbon footprint of the process, leading to an increasing demand for cleaner and more sustainable technologies in industrial processes.

[0005] A promising solution for reducing CO2 and NOx emissions in reheating furnaces is the adoption of alternative fuels, in particular hydrogen combustion.

[0006] Hydrogen offers several advantages over traditional fossil fuels, including clean combustion, producing essentially water, with no CO2 emissions, high energy density and compatibility with existing infrastructure.

[0007] The transition to hydrogen combustion contributes to global decarbonisation efforts in the steel industry.

[0008] As the steel industry continues to evolve, there is increasing recognition of the need to adopt sustainable practices and reduce environmental impacts.

[0009] By taking advantage of emerging technologies, such as hydrogen combustion, and by implementing strategic measures to mitigate NOx emissions, steel producers can not only meet regulatory requirements, but also achieve long-term sustainability goals while maintaining their competitiveness in the global market.

[0010] However, the integration of hydrogen combustion in reheating furnaces requires modifications to existing equipment and infrastructure.

[0011] Existing conventional combustion burners tend to overheat when the usual fuel is replaced by hydrogen. This is because, with hydrogen flames, the flame is closer to the burner due to the higher combustion rate of hydrogen compared to traditional fuels such as natural gas.

[0012] Moreover, these burners generally produce high NOX emissions when fueled with hydrogen.

[0013] A common approach is to replace existing burners with burners optimized for hydrogen combustion. These modified burners are designed to ensure efficient mixing of hydrogen and oxidant, resulting in clean and stable combustion while minimizing NOx formation.

[0014] However, modernizing the process to current NOx standards and adapting it to hydrogen-rich fuels by changing the burners requires significant investment and extensive modifications to the furnace. Such projects are driven solely by regulations with no economic benefit, making the limitation of investment costs a priority.

[0015] Another NOx emission reduction technique described by US8075303 involves using an oxygen lance, where oxygen is injected directly into the furnace to improve combustion and heating efficiency. While effective in some applications, the oxygen lance may not be suitable for furnaces where oxygen availability is limited.

[0016] In most cases, the financial gain from reduced fuel consumption resulting from oxygen injection is offset by the additional cost of the oxygen. Thus, the idea is interesting from an environmental perspective but offers no economic benefit in many cases, which may hinder its adoption by industry. Technical background

[0017] Steel reheating furnaces are an integral part of the steelmaking process. Typically, these furnaces use axial flame burners, which produce high-temperature zones in the product due to their intense heat concentration.

[0018] Axial injection of reagents produces long flames necessary to cover the width of the furnace. However, this approach has drawbacks, including uneven temperature distribution across the product's width and high NOx emissions.

[0019] Axial flame burners generate a concentrated flame that radiates directly onto the steel product, resulting in high localized temperatures. While this rapid heating may be advantageous for certain applications, it This often causes temperature variations throughout the product, leading to heterogeneity in mechanical properties across its thickness and potential quality issues. Furthermore, the high combustion temperatures associated with axial burners contribute to the formation of NOx, a harmful oxidizing pollutant and a significant environmental concern.

[0020] This applies not only to axial burners, but also to most conventional burners. The conventional view of combustion is that flame stability is linked to the fact that it is attached to the burner and that it is intense.

[0021] Generally, in most conventional burners, the gas is injected at the center at a moderate or low speed, surrounded by a dominant amount of oxidant injected at a higher speed to create the long flame.

[0022] The available pressure is not always sufficient for recycled gas from steel production, such as mixed gas and coke oven gas for example.

[0023] Another reason for the lower speed is to facilitate burner ignition in cold conditions, at furnace start-up. A lower gas speed improves the mixing of reactants near the burner.

[0024] All these conditions create an intense flame attached to the burner which, in most cases, is unsuitable for the combustion of hydrogen. This is why conventional burners tend to overheat and generate a shorter flame with high levels of NOx when fueled with hydrogen.

[0025] One solution is to limit the concentration of hydrogen in the gas to a certain level that the burner can handle.

[0026] Another solution is to change the material of the burner in contact with the flame. This is not an option for burners in reheating furnaces because they are generally already made of high-temperature refractory concrete. Furthermore, this does not solve the problem of the shorter flame structure and higher NOx emissions.

[0027] To meet these challenges, the adoption of burners with more diffuse combustion and a wide flame has been adopted in steel reheating furnaces, as taught in the applicant's WO2015078862. These burners produce a wider flame profile with a high injection velocity, which facilitates more uniform heating of the product, improves temperature homogeneity, and reduces thermal gradients.

[0028] By distributing heat more evenly over the entire product, wide flame burners help to mitigate problems such as overheating and underheating, thereby improving the quality and uniformity of the product's mechanical characteristics.

[0029] Furthermore, the use of wide-flame burners also offers environmental advantages by reducing NOx emissions. By operating at With lower maximum temperatures and more even heat distribution, these burners promote more complete combustion and lower NOx formation rates. This emission reduction aligns with increasingly stringent environmental regulations and the sustainability goals of the steel industry.

[0030] Due to the greater distance between the oxidant injection and the gas injection, and the wider injection angle, these new burners are generally larger than conventional burners and require a modification of the furnace to be installed.

[0031] While new furnaces are designed with greater heights to accommodate larger burners, most existing furnaces have limitations on the size of burners that can be fitted.

[0032] These large burners increase the risk of introducing more oxygen onto the product surface due to the proximity of the oxidizing jets and the product. Furthermore, large burners are not suitable for front mounting.

[0033] Moreover, although wide flame burners represent a significant improvement over conventional burners in terms of temperature uniformity and emission reduction, it is still possible to optimize them.

[0034] Most burners have a fixed flame structure that does not adapt to the heating requirements of the product. Some burners solve this problem by incorporating several oxidant injection configurations to modulate the flame shape, but at the expense of even larger burners requiring increased furnace volumes, thus impacting furnace heat losses.

[0035] Burners increasingly require greater operational flexibility with regard to fuel, flame shape, and oxidant-fuel ratio. Conventional burners, and even most new burners, lack this flexibility due to their fixed flame shape.

[0036] New burners are being developed to address these technical problems. These new burners are compact, high-recirculation burners, which often use dilute combustion or flameless combustion to reduce NOx emissions.

[0037] One of the solutions available today for adapting hydrogen to existing furnaces is to adopt these burners. Such modernization projects are costly and not suitable for all furnaces. The modifications are not limited to structural work and burner replacement.

[0038] The new burners operate with different heating curves and flame structures, and they impact the product's heating curve. The furnace's control programs and mathematical models must also be adapted to these changes.

[0039] The invention provides a novel solution to these problems. It allows for the easy modernization of existing furnaces as well as the construction of new furnaces. Summary of the invention

[0040] According to a first aspect of the invention, a method is proposed for converting a burner positioned on a wall of an industrial furnace, said burner being supplied with carbon fuel and oxidizer through internal conduits in the burner, characterized in that it comprises the addition of at least one hydrogen injection lance, or of a hydrogen-rich gas, passing through the wall of the furnace and opening into it in the vicinity of the burner, so that the burner is able to use as fuel, at least partially, the hydrogen, or the hydrogen-rich gas, supplied by the injection lance, or lances.

[0041] The invention makes it possible to adapt existing furnaces to new fuels such as hydrogen by adding fuel lances at a certain radial distance from the burner axis. The idea is to add one or more hydrogen injection lances next to any burner in the furnace and to link them to the furnace's fuel flow control.

[0042] The invention thus makes it possible to convert existing furnace burners to hydrogen, or a hydrogen-rich gas, or the entire furnace, with little modification of the existing equipment and at a limited cost.

[0043] It is sufficient to make channels in the wall of the oven by drilling with drill bits, from the external metal wall of the oven on which the burner is fixed until opening into the oven by passing through the refractory, and then to slide the lances into these.

[0044] The lance opens in the vicinity of the burner, for example at a distance from the burner of about 10 to 100 cm.

[0045] The conversion of the burners is carried out without any modification of the existing burners, which reduces the cost.

[0046] The method applies to furnaces with burners installed in any burner configuration, including side, front and arch heating, and regardless of the burner type.

[0047] Without needing to change the burners, the furnace can switch to hydrogen and hydrogen-rich fuels.

[0048] At least partial replacement of a carbon fuel by hydrogen makes it possible to at least partially decarbonize the operation of the furnace.

[0049] The invention relates to reheating furnaces with a method for injecting fuel through lances placed near the burners and converting the furnace in a diluted combustion compatible with hydrogen and low NOx emissions with limited modifications.

[0050] The injection method creates a very dilute combustion and can be adapted to any burner by introducing a number of lances at a certain distance from the burners. The lances are connected to the furnace fuel flow control and can be linked to the fuel control of the burners near which they are positioned. The lances operate independently or in parallel with the existing burner's fuel injection to provide the total amount of heat input required. The existing burner's fuel flow can be reduced or shut off.

[0051] The invention generates homogeneous temperature profiles on the product surface by creating a homogeneous flame. The temperature variation along the longitudinal and transverse axes is reduced. Furthermore, the lateral fuel jets encompass the central oxidizer jet, which reduces the availability of oxygen at the product surface. This leads to less scale formation on the metal load being heated.

[0052] The invention makes it possible to adapt existing furnaces to hydrogen and hydrogen-rich fuels without damaging the burner due to the high temperature of the flame. The flame will be volumetric, occupying a larger space in the furnace, and will not be fixed to the burners since the fuel is injected away from it.

[0053] Advantageously according to the invention, the hydrogen-rich gas is ammonia or a mixture of ammonia and hydrogen.

[0054] Hydrogen is a good candidate to replace fossil fuels, but it is expensive to transport and store. When its production is not close to the point of consumption, it is more cost-effective to transport hydrogen in the form of ammonia. In this case, it is advantageous to burn it directly rather than converting it to hydrogen, which is a very expensive process.

[0055] Ammonia has a very slow maximum combustion speed (0.07 m / s) compared to natural gas (0.37 m / s) or hydrogen (2.91 m / s). Flame stabilization can sometimes be difficult. Advantageously, according to one embodiment of the invention, the gas injected by the nozzles is a mixture comprising mainly ammonia and a small amount of hydrogen, for example 10%, to facilitate flame ignition.

[0056] According to a second aspect of the invention, an industrial furnace is proposed comprising a wall on which a burner is positioned, characterized in that it comprises at least one hydrogen injection lance, or of a hydrogen-rich gas, passing through the wall of the furnace and opening into it in the vicinity of the burner, the burner being able to operate, at least partially, with hydrogen, or hydrogen-rich gas, supplied by the injection lance(s) as fuel.

[0057] According to the invention, the burner is thus able to operate with hydrogen, or a hydrogen-rich gas, as fuel, supplied by the injection lance(s) in addition to the carbon fuel supplied by an internal conduit to the burner, or as a replacement for it.

[0058] The position of the end of the lance located in the furnace and the inclination of the lance relative to the axis of the burner and to the oxidizer and fuel ducts of the burner are chosen so that the burner operates correctly with the fuel supply through the lance.

[0059] Advantageously according to the invention, the end of the lance from which the hydrogen, or hydrogen-rich gas, escapes into the furnace is formed by a converging nozzle capable of creating a coherent jet.

[0060] The use of a converging nozzle capable of creating a coherent jet offers several advantages, including:

[0061] - An increase in the hydrogen injection speed: The design The converging nozzle design accelerates the flow of injected gas by progressively decreasing its cross-sectional area. This generates a higher velocity at the nozzle exit.

[0062] - Better mixing of reactants: A higher injection speed helps to create A more homogeneous mixture of reactants in the combustion zone. A homogeneous mixture is essential for more efficient and complete combustion, thus reducing the formation of hot spots, and the resulting NOx emissions, and unburned combustion products.

[0063] - Precise flame control: The shape of the converging nozzle allows for Improved control of flame shape and direction. This is particularly important in industrial applications where flame position and stability must be precisely controlled for specific processes.

[0064] In summary, the use of a convergent nozzle for the injection of hydrogen, or hydrogen-rich gas, optimizes combustion conditions, thereby improving energy efficiency, reducing pollutant emissions, and contributing to the safety and control of the combustion process.

[0065] The nozzle can be made of resistant metallic or ceramic material that can withstand high temperatures.

[0066] The tip of the lance can be positioned slightly recessed from the inner wall of the furnace to protect the nozzle from radiation, particularly when the nozzle is not gas-cooled. The recess in the inner wall can be small with a ceramic nozzle, due to its high temperature resistance, and larger with a metal nozzle, which has lower temperature resistance.

[0067] Under extreme conditions, the lance can be cooled by an external fluid circulating through a jacket forming part of the lance or external to the lance.

[0068] According to one embodiment of the invention, the longitudinal axis of the injection lance converges towards the axis of the burner, in the direction of flow of the hydrogen, or of the hydrogen-rich gas.

[0069] The angle of inclination of the lance is chosen so that the position of the convergence point is close to or far from the hot face of the burner so as to obtain the desired quality of mixing of hydrogen, or hydrogen-rich gas, with the fuel and / or oxidizer from the burner.

[0070] According to another embodiment of the invention, the longitudinal axis of the injection lance is parallel to the axis of an internal oxidizer duct in the burner.

[0071] Injecting hydrogen parallel to the oxidizer jets delays the interaction between the hydrogen and oxidizer jets, thus diluting the flame as much as possible. This effect can also be achieved by placing the nozzles further from the burner.

[0072] The possibility of delaying the interaction between the hydrogen and oxidant jets is limited by the fact that the oxidant must be present in small quantities on the surface of the product. Therefore, care must be taken to choose the angle and position of injection.

[0073] By maintaining the same momentum as the gas jet initially injected into the burner, the flame structure can be largely preserved, since the oxidation moment is dominant and the flame aerodynamics are not significantly affected. The advantage of this configuration is the minimal impact on the product's heating curve.

[0074] The injection speed and the angle of the lances can vary depending on the aerodynamics of the burner.

[0075] Simulations and experiments show that a low injection velocity of the nozzles does not achieve the dilute flame behavior, especially if the nozzles are close to the existing burner. The fuel is drawn directly by the oxidant injected by the burner and reacts rapidly, as in the case where the fuel is injected by the burner. However, certain advantages are obtained, such as the reduction of oxygen at the surface of the product.

[0076] Since the fuel is injected outside the oxidizer, it surrounds the oxidizer, thereby reducing the oxygen content in the atmosphere near the product. Furthermore, flame takeoff is increased, which protects the burner from overheating.

[0077] On the other hand, injection at a high speed close to or greater than the speed of the oxidant creates a reaction zone in the oxidant recirculation zone favorably maximizing the dilution effect.

[0078] Tests carried out in a test furnace on different types of burners show that this method produces a more homogeneous flame. In all cases tested, hydrogen combustion is achieved with a highly dilute flame. The burner temperature is within acceptable limits, and NOx emissions are improved in most cases and become less dependent on the oxidizing fuel ratio.

[0079] According to one embodiment of the invention, the furnace comprises two hydrogen injection lances, or of a hydrogen-rich gas, arranged on either side of the burner and symmetrically with respect to the axis of the burner, the two lances being able to be arranged on the vertical or horizontal axis of the burner.

[0080] The lances can be positioned on a horizontal plane including the axis of the burner, symmetrically on either side of it.

[0081] The lances can also be placed on a vertical plane including the burner axis, on either side of a metal product being heated in the furnace. This configuration can create a fuel-rich layer near the surface of the product, thereby reducing scale formation on the product.

[0082] The positioning may be different depending on the oven configuration.

[0083] The use of two lances arranged in this way is advantageous because it promotes the development of a symmetrical flame along the axis of the burner, without protrusion on the side where the lance is located when only one lance is used.

[0084] According to another embodiment of the invention, more than two lances are positioned around a burner.

[0085] According to a third aspect of the invention, a method for controlling a furnace according to the invention is proposed, characterized in that the proportion of fuel supplied by the injection lance (or lances) is between 1% and 100% of the total fuel in the burner.

[0086] Thus, depending on the availability of hydrogen and / or the cost of hydrogen, or hydrogen-rich gas, the process makes it possible to adjust the proportion of hydrogen consumed. This proportion will be high if hydrogen availability is high and its cost is low, and it will be low if hydrogen availability is low and its cost is high.

[0087] Modulating the proportion of fuel supplied by the injection nozzles can modify the flame structure. In cases where all the fuel is injected via the nozzles, the flame is most diluted and we create a flameless mode.

[0088] The lances of a burner can be coupled to each other and to those of adjacent burners, or operate separately.

[0089] The amount of fuel injected through the lances is monitored and controlled by a program integrated into or operating with the furnace's fuel supply system.

[0090] With proportional control, flow regulating valves are required. For different fuels, the nozzles are connected to a different gas supply.

[0091] When the furnace is cold, the burners start in conventional mode, but some of the fuel can also be injected through the nozzles. As the furnace temperature increases and reaches the auto-ignition temperature, more fuel can be injected through the nozzles, up to 100% under high-temperature conditions and in production mode.

[0092] Advantageously according to the invention, the proportion of fuel supplied to the burner by the injection lance(s) is adjusted according to the temperature of the furnace.

[0093] It is thus possible to control the furnace temperature, and / or the furnace temperature profile, by adjusting the proportion of hydrogen or hydrogen-rich gas. This proportion is reduced when it is advantageous to lower the furnace temperature and, conversely, it is increased when it is advantageous to raise the furnace temperature.

[0094] Hydrogen, or hydrogen-rich gas, can be injected into the furnace at a speed substantially lower or higher than the speed of injection of the burner oxidant into the furnace, for example between 50% and 200% of the speed of injection of the oxidant.

[0095] Advantageously according to the invention, hydrogen, or hydrogen-rich gas, supplied by an injection lance is injected into the furnace at a speed between 80% and 150% of the injection speed of the burner oxidant into the furnace.

[0096] The existing burners are connected to the oxidizer circuit for oxidizer injection and to the fuel circuit for fuel injection. The fuel and oxidizer are delivered to the furnace in a specific proportion to achieve combustion. The generated flame heats the product. The burners operate using digital control (also known as pulse ignition), proportional control, or a hybrid of the two.

[0097] Advantageously according to the invention, the fuel is injected totally or mainly via the lances, without modification on the injection of oxidant which continues to be delivered by the burner. Brief description of the figures

[0098] Other features and advantages of the invention will become apparent upon reading the detailed description that follows, for understanding which reference should be made to the accompanying drawings in which:

[0099] [Fig. 1] is a schematically and partially represented front view of a furnace wall on which a burner is mounted according to the prior art,

[0100] [Fig. 2] is a schematically and partially represented vertical cross-sectional view of the wall of [Fig. 1] on which the burner is mounted according to the prior art,

[0101] [Fig. 3] is a view similar to [Fig. 1] after the addition of two injection lances according to an exemplary embodiment of the invention,

[0102] [Fig.4] is a view similar to [Fig.2] after the addition of the two injection lances according to the exemplary embodiment of the invention in [Fig.3],

[0103] [Fig.5] is a schematically and partially represented longitudinal sectional view of a pre-rolling reheating furnace according to an exemplary embodiment of the invention,

[0104] [Fig.6] is a partial and schematic view of a lance according to an exemplary embodiment of the invention, comprising a metallic nozzle 61, and,

[0105] [Fig. 7] is a partial and schematic view of a lance according to an exemplary embodiment of the invention, comprising a nozzle 61 made of ceramic material. Detailed description of the invention

[0106] Fig. 1 partially shows, in front view from inside the furnace, a wall 3 of a pre-rolling preheating furnace 200 comprising a burner 100 according to the prior art. The burner comprises an opening 13 made of refractory material with a central gas pipe 4, and four air injectors 5 arranged around the central gas pipe at equal intervals. Two air injectors are positioned on a vertical plane 10 passing through the axis of the burner, and two air injectors are positioned on a horizontal plane 11 also passing through the axis of the burner.

[0107] In [Fig.2] is partially shown the wall 3 of the furnace 200 of [Fig.1], in vertical section along the plane 10 passing through the axis of the burner of [Fig.1]. The burner 100 further comprises a metal casing 12 and a combustion air inlet 14.

[0108] Figure 3 shows a furnace 2 comprising a burner 1 similar to that of Figure 1. Two lances 6 have been added, according to one embodiment of the invention, for the injection of hydrogen or a hydrogen-rich gas. They are arranged on the plane 10 of Figure 1, on either side of the burner and symmetrically along the axis of the burner.

[0109] As shown in [Fig.4], the lances pass through the wall of the furnace which has been previously pierced to receive them.

[0110] In this example, the lances have at their end a nozzle 61 whose tip 62 is slightly recessed from the hot face of the wall 3 of the furnace in order to limit its temperature. This is particularly advantageous when the nozzle 61 is metallic.

[0111] The inclination of the spears is chosen so that the longitudinal axes of the The lances converge towards a point located on the axis of the gas pipe 4 at a determined distance from the opening. This distance from the point of convergence is chosen according to the nature of the burner, in particular the arrangement of the oxidizer and fuel ducts, the nature of the main fuel of the burner, and the desired flame shape.

[0112] The number, position and mode of operation of the oxidizer ducts, some of which may or may not be supplied depending on the operating regime of the burner, are taken into account in particular when deciding on the position and inclination of the lances.

[0113] In another example of an embodiment not shown, the lances may be horizontal, without inclination, parallel to the fuel conduits 4 and the oxidizer conduits 5.

[0114] The position and inclination of the lances can in particular be determined by numerical simulation or by tests.

[0115] Figure 5 schematically illustrates another application of the invention for a pre-rolling reheating furnace 2. The furnace is shown in longitudinal section, with the products to be reheated, not shown, circulating from left to right. In this example, two lances 6 are arranged on either side of each burner 1 on a horizontal plane. This arrangement is advantageous in this type of furnace where a flat flame is desired to distribute heat over the products.

[0116] Fig. 6 partially and schematically illustrates a lance 6 according to an example of an embodiment of the invention, comprising a metallic nozzle 61.

[0117] Fig. 7 partially and schematically illustrates a lance 6 according to another embodiment of the invention, comprising a nozzle 61 made of ceramic material.

Claims

Demands

1. A method for converting a burner (1) positioned on a wall (3) of an industrial furnace (2), said burner being supplied with carbon fuel and oxidizer through conduits (4, 5) internal to the burner, characterized in that it comprises the addition of at least one hydrogen injection lance (6), or of a hydrogen-rich gas, passing through the wall of the furnace and opening into it in the vicinity of the burner, so that the burner is able to use as fuel, at least partially, the hydrogen, or the hydrogen-rich gas, supplied by the injection lance(s).

2. A process according to claim 1, characterized in that the hydrogen-rich gas is ammonia or a mixture of ammonia and hydrogen.

3. Industrial furnace (2) comprising a wall (3) on which is positioned a burner (1), characterized in that it comprises at least one hydrogen injection lance (6), or of a hydrogen-rich gas, passing through the wall of the furnace and opening into it in the vicinity of the burner, the burner being capable of operating, at least partially, with hydrogen, or hydrogen-rich gas, supplied by the injection lance(s) as fuel.

4. Oven according to claim 3, characterized in that the end of the injection lance (6) from which hydrogen, or hydrogen-rich gas, escapes into the oven is formed by a converging nozzle capable of creating a coherent jet.

5. Oven according to any one of claims 3 or 4, characterized in that the longitudinal axis of the injection lance (6) converges towards the axis of the burner, in the direction of flow of the hydrogen, or of the hydrogen-rich gas.

6. Oven according to any one of claims 3 to 5, characterized in that the longitudinal axis of the injection lance(s) (6) is parallel to the axis of the internal oxidizer conduit(s) (4) of the burner.

7. Furnace according to any one of claims 3 to 6, characterized in that it comprises two hydrogen injection lances (6), or lances of a hydrogen-rich gas, arranged on either side of the burner and symmetrically with respect to the axis of the burner.

8. A method for controlling an industrial furnace (2) according to any one of claims 3 to 7, characterized in that the proportion of fuel supplied by the injection lance(s) (6) to a burner (1) is between 1% and 100% of the total fuel in the burner.

9. Method according to claim 8, characterized in that the proportion of fuel to the burner (1) supplied by the injection lance(s) (6) is adjusted according to the temperature of the furnace.

10. A method according to any one of claims 8 or 9, characterized in that the hydrogen, or hydrogen-rich gas, supplied by an injection lance (6) is injected into the furnace (2) at a speed between 80% and 150% of the injection speed of the oxidant from the burner (1) into the furnace.

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