Abstract: The invention relates to a combustion tool including a quarl block made of refractory material, the quarl block defining a quarl exit and a passage between the entry surface and quarl block, said tool including an injector of oxidizer and/or fuel that extends through the passage and opens into the quarl block, and also including a sheath that surrounds the injector in the passage section.

Abstract: The invention relates to a process of producing ageing gas for ageing components for the after-treatment of exhaust gas in a burner which comprises a combustion chamber with at least one fuel injection nozzle and with a combustion gas supply system with means for generating swirl, wherein the swirl of the combustion air is set as a function of the selected combustion air ratio ?.

Abstract: Combustor. The combustor includes an axially symmetric tube along with means for introducing fuel and air into the tube. A swirler is disposed within the tube to impart rotation in a first direction to the air/fuel mixture. A plurality of holes downstream of the swirler are disposed around the tube and offset at an angle relative to an inward normal to the tube wall. Air is injected through the offset holes to impart rotation to the air/fuel mixture in a second direction opposite to the first direction. A combustion chamber having a diameter larger than that of the tube receives and burns the air/fuel mixture from the tube.

Abstract: A flare apparatus for burning combustible gases. A flare tip unit comprises an inner member and an outer member defining an annulus therebetween. The annulus defines an annular gas passage through which combustible gas passes. Air moved by a motive force, preferably steam, passes through the inner member and a steam/air mixture exits an outlet of the inner member. The combustible gas and an air/steam mixture mixes in a premix zone between the inner member outlet and the exit opening of the outer member. The combustible gas/air/steam mixture is ignited for burning in the atmosphere above the exit opening. The flare apparatus may include a plurality of flare tip units.

Abstract: A method for generating combustion by means of a burner assembly and corresponding burner assembly are disclosed. The burner assembly comprises a refractory block, a fuel supply system and an oxidant supply system. The refractory block defines along one plane P1 at least one fuel passageway extending from a fuel inlet port to a fuel outlet port, and along a second plane P2 at least one oxidant passageway extending from an oxidant inlet port to an oxidant outlet port, said first and second planes intersecting along a line that is beyond said outlet ports, said oxidant supply system comprising a pair of oxidant supply means, an inlet of the inner oxidant supply means being connected to a source of a first oxidant having a first oxygen concentration and an inlet of the concentric outer oxidant supply means being connected to a source of a second oxidant having a second oxygen concentration, the method having improved flexibility in oxygen concentration in the oxidant.

Abstract: An air-gas premixing device to be inserted into a low-NOx gas burner. The device comprises a ring nut adapted to rotate about a symmetry axis passing through its geometric center. The rotation of the ring nut causes: the rotation of a shutter for closing/opening an air-passage section for a fraction of the air from a ventilation group; and the rotation of a premixing pipe provided with an eyelet for the passage of a combustible gas; so that the air and the combustible gas are mixed in said premixing pipe to obtain a decrease of NOx emissions.

Abstract: The cooking appliance (1) having a control panel (2) is equipped with one or more gas flow (Q) regulating valves, wherein the rotary regulating plug (6) is provided with various peripheral through holes (16-19). The control knob (9) being interchangeable for fitting to the actuating shaft (7), is chosen from the two units available, one and the other permitting different angular limit positions of the regulating plug (6) for the supply of a constant minimum gas flow Qmin, adjusted each one for a different type of gas N gas or LP gas. The outlet conduit (5) of the valve is equipped with a further injector nozzle (21,23) for adjusting a constant gas flow Qmax to be fed into the conduit (25) of the correspondent burner, when the cooking appliance is supplied with a LP gas.

Abstract: An air/gas premix burner, comprising: a fan for sending the air/gas mixture to a combustion head; a gas valve for regulating admission of the combustible gas; an air/gas mixer, which comprises a device for localized loss of pressure; and a combustion head. The premix burner is characterized in that the air/gas mixer comprises at least two channels for mixing the air with the gas; in addition, a channel is provided with an open/close element designed to regulate the flow rate of the mixture.

Abstract: The invention relates to a device for continuously preheating a mixture of burnable gas, particularly natural gas and oxygen, prior to the catalytic combustion thereof, wherein the combustion heat thereof can be used to heat fed-out natural gas, before or after the expansion thereof and supply to consumers, in order to compensate for the Joule-Thomson effect. The device is designed as a jet pump having a propelling nozzle and a diffuser aligned therewith. The propelling nozzle is the inlet for the mixture into a mixing chamber disposed in the pump housing, a suction line for the natural gas heated by means of catalytic combustion being connected to the chamber. The diffuser is part of an outlet of the mixing chamber of the jet pump. The propelling nozzle and the diffuser are disposed such that they can be moved relative to one another in the pump housing.

Abstract: Cooking appliance having an external and control panel equipped with one or more regulating valves, where the rotary regulator organ is equipped with various peripheral openings for supplying a flow Q. According to two embodiments of the cooking appliance, for the supply of one or another type of gas, NG or LPG, either the control knob or a bezel disk in the external panel are interchangeable on the appliance, being chosen between two different available units, one and the other permitting two different angular position limits A2, A3 of the regulator organ for the supply of a constant flow Qmin through one or another opening with calibrated sections, respectively for NG or LP gas. An appendix in the control knob guided in a slide groove on the control panel of the appliance, or a tongue on the bezel disk stopping the rotation of the control knob, determines the travel limit A2 for the supply of Qmin of NG.

Abstract: A gas burner apparatus for discharging a mixture of fuel gas, air and flue gas into a furnace space of a furnace wherein the mixture is burned and flue gas having a low content of nitrous oxides and carbon monoxide is formed is provided. The burner tile includes at least one gas circulation port extending though the wall of the tile. The interior surface of the wall of the tile includes a Coanda surface. Fuel gas and/or flue gas conducted through the gas circulation port follows the path of the Coanda surface which allows more flue gas to be introduced into the stream. The exterior surface of the wall of the tile also includes a Coanda surface for facilitating the creation of a staged combustion zone. Also provided are improved burner tiles, improved gas tips and methods of burning a mixture of air, fuel gas and flue gas in a furnace space.

Abstract: A swirler vane for providing fuel, particularly liquid fuel, to a swirling zone of a burner assembly is provided. The swirler vane includes at least one injection hole for injecting the fuel to the swirling zone of the burner and an injection feed hole passage connecting the at least one injection hole with a main fuel feed. The swirler vane or a tip of the swirler vane, where the at least one injection hole is arranged, is manufactured by laser deposition or includes at least a surface manufactured by laser deposition. A swirler including a plurality of such swirler vanes and a burner assembly including the swirler with such swirler vanes are also provided.

Abstract: A heating cooking appliance and a burner system thereof are provided. The height of the burner pot is reduced to facilitate product installation and reduce overall material and shipping costs. To increase user satisfaction with the product, a plurality of mixing tubes are extended in the same direction on one side of the burner pot in the burner system.

Abstract: The present application provides a secondary fuel nozzle assembly for a combustor. The secondary fuel nozzle assembly may include a liner, a fuel passage leading to a pilot burner tip, and a venturi extending from the liner and downstream of the pilot burner tip.

Abstract: A burner carrier flange and a burner with such a burner carrier flange are provided. A surface of the burner carrier flange potentially comes into contact with fuel. The burner carrier element includes a base material and a corrosion-resistant material and the surface that potentially comes into contact with fuel is made of the corrosion-resistant material.

Abstract: In an all primary combustion burner, a partition plate that demarcates a mixing chamber between the partition plate and a bottom wall section of a burner main body and a distributing plate that sections a space between the partition plate and the combustion plate into a first distributing chamber and a second distributing chamber are provided in the burner main body to cause a fuel gas and a primary air to flow into the mixing chamber A pressure loss is minimized to make it possible to satisfactorily mix the fuel gas and the primary air. An outlet is formed on a downstream side of the partition plate. A guide plate section that extends to the downstream side while inclining in a normal direction, which approaches the bottom wall section of the burner main body, from an edge on the upstream side of the outlet, is provided in the partition plate.

Abstract: A burner for melting material in a furnace includes an elongated member having a first end with a heat source, a second end with an exhaust, and a combustion chamber disposed in the elongated member interconnecting the first and second ends, a portion of the elongated member between the first and second ends in contact with the material to be melted. A method for melting the material is also provided.

Abstract: Method and device for combusting a solid phase fuel, where the fuel is caused, by the help of a non-pneumatic feeding element (11), to be fed to an inlet opening (11a) in a burner device (10), where the burner device (10) includes a first inlet (13a) for the oxidant through which an oxidant is caused to flow via a first supply conduit (13). The first inlet (13a) for oxidant is arranged in the form of a first opening arranged by the inlet opening, through which the oxidant is caused to flow out, through a burner pipe (16) and out through a burner orifice (17) to a combustion space (18), so that the oxidant by ejector action causes the fuel to be conveyed through the burner pipe and out through the burner orifice (17), and water vapour is added to the oxidant before the oxidant reacts with the fuel.

Abstract: A gas burner apparatus comprising a burner base disposed over a gas burner, a burner head disposed over the burner base, and one or more burner covers disposed over the burner head. A method comprising a burner base over a gas burner, providing a burner headwith one or more burner ports over the burner base, providing one or more burner covers over the burner head, and sliding one or more burner covers over at least one of the one or more burner ports.

Abstract: A gas burner including a burner body having a lower housing, an inlet conduit and a combustion surface element attached to the lower housing. A diffuser/reflector positioned within the body encourages even distribution and mixing of a combustible gas/air mixture. The diffuser/reflector is preferably of a sheet metal construction and includes a plurality of stamped openings with each of these openings having an overhanging guide plate. The combustion surface element includes a plurality of integrally formed rigidizing ribs and is made from a high temperature steel alloy wire cloth. The inlet conduit is secured directly or indirectly to an access door/bulkhead that is used to close off an access opening formed in a water heater wall through which the burner is installed. In one construction, an air scoop shrouds the inlet conduit and at least partially defines a flow path of primary air, substantially isolated from the combustion chamber.

Abstract: This invention is directed to supply a combustor having a structure that reduces NOx emissions while maintaining combustion stability. The combustor has a chamber into which fuel and air are supplied. An air hole plate having a plurality of air holes upstream of the chamber is also disclosed, and fuel nozzles supplying fuel to the air holes of the air hole plate are further disclosed. In the combustor, a center of a chamber-side of the air hole plate is closer to the chamber than exits of outermost peripheral air holes.

Abstract: The invention relates to: a combustion process, especially for melting glass, in which a flame is created by gaseous fuel, characterized in that several regularly spaced peripheral low-pressure gas jets converge on a central high-pressure gas jet; an injector for implementing this process; a burner comprising one or more such injectors; and a furnace comprising at least one such burner.

Abstract: A burner arrangement is provided including a swirl-generating premix burner for providing a fuel/air mixture produced with a first fuel as well as a mixing pipe adjoining the premix burner downstream thereof and extending into a combustion chamber. In the case of such a burner arrangement, safer operation with highly reactive, in particular H2-rich fuel is achieved by the mixing pipe having a constriction downstream of the outlet of the swirl generator, and by a feeder for spraying in the highly reactive, in particular H2-rich fuel being arranged at the level of the constriction.

Abstract: A method for producing hot gas for operating a turbomachine fired with at least one combustion chamber includes premixing a fuel with a plurality of operating gases by introducing fuel into the plurality of operating gases in a mixing chamber disposed upstream of the combustion chamber using a burner arrangement, wherein the fuel includes at least one of a combustible gas and a H2-rich fuel; and introducing the premixed fuel into the combustion chamber.

Abstract: The invention concerns a gas burner (1) with multiple concentric flame rings, comprising: a central burner (2) with a central ring of flame orifices (5), and axial central gas injector (6) and convergent-divergent means (7) forming venturi; and an annular outer burner (3) coaxially surrounding the central burner and provided with at least one annular ring of flame orifices (9), gas injecting means (10) and convergent-divergent means (12) forming venturis; the gas injecting means (10) include several radial gas injectors (11) around the central injector (6); the convergent-divergent means (12) include several radial convergent-divergent conduits (13) forming tubular venturis coaxial respectively to the radial injectors (11) and emerging in the annular outer burner.

Abstract: Disclosed is a device and a method for maintaining and operating a flame. The device has a burner, a burner attachment having an outlet geometry, wherein on a side of the burner attachment facing away from the burner, an anode is provided on one side of the outlet geometry of the burner attachment. A dielectric is provided on the other side of the outlet geometry, wherein a cathode is located in the dielectric. The device and method: do not require continuous flame monitoring; positively influence the deposition behavior of layer-forming components of the fuel gas flame; and reduce the thermal impact of the burner and the operating costs thereof.

Abstract: Disclosed is a mixing hole arrangement for improving homogeneity of an air and fuel mixture in a combustor, the mixing hole arrangement comprising a plurality of mixing holes defined by a liner, wherein at least one of the plurality of mixing holes is a mixing hole that is at least one of sized and positioned to impede penetration of a fluid flow into a primary mixing zone located in a head end of the combustor.

Abstract: A wire mesh burner plate for use in large, gas burners for large ovens is comprised of spaced-apart wire mesh plates. The spacing between the wire mesh plates defines an air/fuel mixture space. The fuel passes through the lower or first mesh, experiences a pressure drop, mixes with air and passes through a second wire mesh. The gas combusts after passing through the second wire mesh. The fine gauge of the mesh prevents combustion from flowing backwardly into the fuel/air mixture space. Several individual wire mesh burner plates can be flexibly attached to each other such that a very wide space can be covered. Thermal stresses are reduced by being distributed across multiple burners.

Abstract: A gas burner for cookers of the type fitted to a cooking hob includes a central body having a first flame distribution ring and at least one external body, fluidly separated from the central body and substantially concentric with it, having at least one second flame distribution ring. In addition, structure is provided for separately feeding the mixture of primary air and gas to the central body and to the external body. This structure includes at least one horizontal mixing chamber with a radial Venturi effect.

Abstract: What are described are a multiple burner arrangement and a method for operating such a multiple burner arrangement with a multiplicity of individual burners which are designed as premix burners and which serve for firing a combustion chamber of a thermal engine and each have a swirl space into which combustion supply air and fuel can be introduced so as to form a swirl flow, the swirl flow forming downstream of the premix burner, within the combustion chamber, a backflow zone in which a burner flame is formed.

Abstract: A burner assembly for a radiant tube heater having an air duct portion for passage of combustion air to a radiant tube portion includes a mixing cup for mixing combustible gas and air and delivering the mixture to the tube. This cup has an inlet portion and a larger cylindrical outlet portion. Air inlet holes are formed in an upstream end wall of the outlet portion and air ports are formed in a peripheral wall of the inlet portion. An air diverter mounted at an upstream end of the inlet portion has a set of blade which divert a portion of the air through the ports for initial mixing with the gas while a second portion of the air flows through the inlet holes providing additional primary air for mixing. An airflow restricting plate can be mounted on the cup so as to extend circumferentially around the cup.

Abstract: A burner assembly for a gas powered cooking appliance is provided. The burner assembly may include a burner body including a central region and a plurality of radiating extensions extending radially outward from the central region. The burner assembly may include a burner cap with a central region and a plurality of radiating extensions extending radially outward from the central region. The burner cap is positioned on top of the burner body when the burner is assembled. The burner cap may include at least one overhang positioned on the outer perimeter of the central region and between an adjacent pair of radiating extensions. The at least one overhang forms a gap between the exterior wall of the burner body and the interior wall of the overhang. This gap, or flame stabilization chamber, provides for collection of gases and flame that aid in maintaining the flame during low temperature operation.

Abstract: A method and a device for combusting gaseous fuel which contains hydrogen or consists of hydrogen, includes a burner which provides a swirl generator (1) into which liquid fuel is feedable centrally along a burner axis (A), forming a liquid fuel column which is conically formed and which is enveloped by, and mixed through with, a rotating combustion air flow which flows tangentially into the swirl generator (1). The gaseous fuel is fed inside the swirl generator (1) largely axially and/or coaxially to the burner axis (A), forming a fuel flow with a largely spatially defined flow pattern (9) which is maintained inside the burner and bursts open in the region of the burner outlet.

Abstract: A method for producing a fuel nozzle is provided. In the method a swirl duct is mounted in an outer jacket surface of a pin and/or in an inner surface of a sleeve and the pin is attached in the sleeve so that the outer jacket surface of the pin is connected to the inner surface wherein the pin is disposed in the sleeve. The outer jacket surface of the pin and/or the inner surface of the sleeve includes at least one-swirl duct. A fuel nozzle and a burner are also further disclosed wherein the burner includes the fuel nozzle.

Abstract: A burner apparatus utilizes a reticulated member to promote mixing of a fuel and oxidizer mixture. A plurality of exit ports, disposed on a wall or surface encapsulating the reticulated member, defines exit streams of the mixture that produces flames upon combustion. The burner apparatus have high heating rates and turndown ratios of at least about 18:1.

Abstract: A gas burner including a burner body having a lower housing, an inlet conduit and a combustion surface element attached to the lower housing. A diffuser/reflector positioned within the body encourages even distribution and mixing of a combustible gas/air mixture. The diffuser/reflector is preferably of a sheet metal construction and includes a plurality of stamped openings with each of these openings having an overhanging guide plate. The combustion surface element includes a plurality of integrally formed rigidizing ribs and is made from a high temperature steel alloy wire cloth. The inlet conduit is secured directly or indirectly to an access door/bulkhead that is used to close off an access opening formed in a water heater wall through which the burner is installed. In one construction, an air scoop shrouds the inlet conduit and at least partially defines a flow path of primary air, substantially isolated from the combustion chamber.

Abstract: A high-efficiency hot-water boiler for a heating system of a building is provided. The boiler includes a boiler enclosure that contains a furnace area compartment within an insulated sealed casing, a first watertube compartment within a sealed casing, a second watertube compartment within a sealed casing, and an air-to-air preheat exchanger within a sealed casing. A plurality of separate, closely-spaced watertubes extends within each of the compartments and provides paths for working fluid to flow through the compartments for purposes of transferring heat to the working fluid. A burner is located within the furnace area compartment for combusting an air/gas mixture.

Abstract: The invention relates to a gas burner comprising a perforated cylindrical wall used as a combustion surface, a bottom wall and an inlet opening through which a combustible gaseous mixture is fed inside the burner. The stabilisation device consists of a grid (4a) that can be positioned in the inlet opening of the burner, and that comprises a central ring (5a) surrounded by a series of diverting vanes (6), the grid being thus configured so as to allow the free passage of the central portion of the flow of gaseous mixture entering the burner through the central ring (5a) while said diverting vanes (6) generate an eddy movement in the peripheral portion of the flow entering the burner from the outside of the central ring (5a).

Abstract: The invention relates to a device for providing a gas/combustion air mixture for a gas burner, comprising a fan (11) for providing a combustion air flow, a gas control device for providing a gas flow and a mixing device (13) for mixing the combustion air flow and the gas flow, thus providing the gas/combustion air mixture. Said mixing device (13) and the fan (11) we connected together on one side, and on the other side, the mixing device and the gas control device are corrected together. According to the invention, the mixing device (13) and the fan (11) we connected together in such a manner that a vibration absorber (15) is arranged between a connecting section (12) of the mixing device (13) and a connecting section (10) of the fan (11).

Abstract: A portable cross-fire burner flameworking device includes a table, two or more gas hookups, two or more regulator and flow meter pairs respectively connected so as to be able to receive gas from the gas hookups, two or more control valves respectively connected so as to be able to receive gas from the regulator and flow meter pairs, and two burners having burner heads each connected so as to be able to receive gas from the two or more control valves mounted on the table. Each burner head has a burner face, and the burner faces are oriented towards each other at a distance. The two or more gas hookups are connected to the table so as to be portable therewith, the two or more regulator and flow meter pairs are connected to on the table so as to be portable together therewith, the two or more control valves are connected to the table so as to be portable therewith, and the two burner heads are likewise connected to the table so as to be portable together therewith.

Abstract: The invention relates to a burner system having a number of premixed burners (2), which each have one or more feed openings and outflow openings for a combustible gas/air mixture. The burner system is provided with means (11) for transferring a flame from one burner to another. By making use of such flame transfer means the burner system can be ignited at one of the burners, wherein the flame then overflows sufficiently -rapidly to the other burners in order to ignite them before a dangerously large quantity of the combustible gas/air mixture has flown out. These flame transfer means can define a flame path between the burners which can for ijistance be formed by an overflow pipe (12) mutually connecting the burners. The burner system can further be provided with a member (13) directed toward the flame path for the purpose of injecting the combustible gas/air mixture (M) therein. This injection member can be connected via a branch conduit (14) to a mixing chamber (5) in which the gas/air mixture is formed.

Abstract: The invention relates to a method of combustion of a fuel using an oxygen containing gas and at least one mainly inert gas, in which: the said oxygen containing gas comprises at least 80% of oxygen in volume, the said fuel and the said oxygen containing gas are injected in such a way as to create a flame, the said mainly inert gas is injected in such a way that it is contiguous to and surrounds the flame created by the said fuel and the said oxygen containing gas and that it has a divergent swirl with regard to the flame.

Abstract: A fuel nozzle tip for use with a combustor and a method of assembling the fuel nozzle tip are provided. The fuel nozzle tip includes a fuel tube and an air collar coupled to the fuel tube. The fuel tube includes a first plurality of circumferentially-spaced fuel openings and a second plurality of circumferentially-spaced fuel openings. The fuel tube is configured to channel fuel into a mixing zone defined within the combustor. The air collar includes a plurality of circumferentially-spaced air openings configured to discharge air into the mixing zone. At least one of the plurality of air openings is oriented to facilitate generating a swirl number of greater than 0.6 within the mixing zone.

Abstract: A pulse detonation device for dividing a pulse detonation shock wave into an primary and control portion to reduce the strength of a propagating shock wave and/or change its direction. The device contains a flow separator which directs a portion of the shock wave into itself, thus reducing the shock wave's strength. In one configuration, the control region converges in cross-sectional area so as to accelerate the flow in the control region, while the primary region diverges to slow the flow in the primary region. The flow in the control region is directed, at an angle, into the flow of the primary region to impede and/or redirect the flow of the primary region.

Abstract: What is shown is an improved gas burner assembly that is easily adapted to attach to a range top or cooktop, or the floor of the range and can draw air from either above the range top level by external vents or from below range top level through an open style mixing cup. The improved gas burner assembly uses a plurality of flame rings providing the user a wide variety of temperature settings starting from a low intensity simmer to high intensity cooking heat. A gas transfer channel provides a sustaining ignition source. The gas transfer channel has sustaining flame buttons interior to the burner body, and provides the initial ignition for the main flame rings. The gas transfer channel additionally has slots that provide additional sustaining flames for the main flame rings located on the exterior of the burner body.

Abstract: A burner has a pot provided with an inlet for a gas mixture to be burned and a cap that sits on top of the pot. The pot and the cap define both a central zone for combustion of the gas mixture, and a peripheral chamber that extends around the central zone and communicates with the gas inlet. A plurality of passageways allow the gas mixture to flow from the peripheral chamber into the central zone. A deflector separates, in a non-leaktight manner, the chamber into a lower subchamber, located substantially in the extension of the inlet, and an upper subchamber adjacent said passageways.

Abstract: A device for combusting fuel which contains or consists of hydrogen, is described, with a burner provided with a swirl generator and also a feeder for feeding fuel and a feeder for feeding combustion air into the swirl generator. A first feeder, for feeding liquid fuel along a burner axis, and a second feeder for feeding liquid fuel or gaseous fuel along air inlet slots which are tangentially delimited by the swirl generator, with a transition section connected downstream to the swirl generator, and with a mixer tube connected downstream to the transition section and with a changeable flow cross-sectional transition leads into a combustion chamber are provided. Along the transition section, a third feeder for feeding fuel which contains or consists of hydrogen, and also a fourth feeder for the selective feed of fuel which contains or consists of hydrogen, or of the gaseous fuel are also provided.

Abstract: A gas circuit with a pilot light system for ranges includes pilot tubes from a gas manifold to burner assemblies. Quick connect couplings are provided between the pilot tubes and manifold so that the pilot tube can be removed easily. Two or more tubes can be connected to a single coupling. A master shutoff interrupts flow to the cooktop without interrupting flow to the oven.

Abstract: A burner head is constructed with adjacent gas delivery tubes of different geometric cross-section shapes which are mechanically held in place radially. The tubes touch in a longitudinal direction at points along their respective inner and outer circumferences so that precise axial alignment whether coaxial or axially offset, is achieved while preserving the necessary laminar gas flow. This configuration greatly speeds the production time which allows economical burners to be produced even when a greater number of faceplate jets is desired. The tube-to-tube contact is also beneficial to the operation of the burner by providing a heat transfer path away from the innermost tube, which prevents overheating. Examples of the simplest geometric tube shapes employed are, for example, a square within a circle, or conversely, a circle within a square.

Abstract: A NOx suppression apparatus is configured for use with a burner that injects fuel into a stream of process air flowing into and through a rotary kiln. The apparatus comprises a premix injection system that forms a premix of fuel gas and air, and injects the premix into the stream of process air upstream of the burner port. This enables premix products of combustion to suppress the production of NOx by vitiating a combustion air portion of the process air before the combustion air portion combusts with fuel injected from the burner port.