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: The invention comprises a combination burner for the gasification of pulverized fuels with an oxidation means containing free oxygen at ambient or higher pressures, as well as temperatures between 800-1800° C., with the ignition device of the pilot burner with flame monitoring and the pulverized fuel burner being integrated as a combination burner and all operating channels being routed separately from each other up to the mouth of the burner and the media carried by the channels only being mixed at the mouth of the burner. When the pilot burner is dismantled the eddy bodies 14 attached to its sleeve in the main burner oxidation means supply 17 can be exchanged quickly and easily and thus the main burner flame adapted in the optimum way to the reaction chamber contour of the reactor.

Abstract: A direct flame impingement burner including a metal block with a fuel inlet and an oxidant inlet and at least two outlet nozzles having a set of identical nozzle outlet openings. The oxidant inlet is connected with an oxidant chamber within the block that is connected with at least one oxidant outlet opening in the set of nozzle outlet openings by passageways of identical length and cross-sectional area. The fuel inlet is connected with a fuel chamber within the block that is connected with at least one fuel outlet opening in the set of nozzle outlet openings by passageways of identical length and cross-sectional area. The fuel gas pressure is equal over all corresponding fuel outlet openings in the set of openings in each nozzle, and the oxidant gas pressure is equal over all corresponding oxidant outlet openings in the set of openings in each nozzle.

Abstract: A method and a burner for combustion in a heating furnace of a fuel with an oxidant in the form of oxygen gas, wherein fuel and oxidant are supplied to a burner head. Fuel and oxidant, respectively, are injected via the burner head through at least two pairs of nozzles, wherein one nozzle pair is defined by a separate fuel nozzle and a separate oxidant nozzle. The nozzles of the nozzle pairs are uniformly distributed over the furnace-interior-facing surface of the burner and within the circumference of the burner head. An oxidant nozzle is provided on each side of a fuel nozzle.

Abstract: A burner nozzle assembly includes: a nozzle plate having an anode off-gas (AOG) nozzle at the center of the nozzle plate and a plurality of oxidation fuel nozzles surrounding the AOG nozzle; and a channel unit coupling the AOG nozzle with an AOG introducer to allow an AOG to flow therebetween and coupling the oxidation fuel nozzles with an oxidation fuel introducer to allow an oxidation fuel to flow therebetween.

Abstract: A vented, gas-fired air heater especially designed for temporary heating applications includes an improved burner design providing effective air and gas mixing and efficient burning in the combustion chamber. Highly efficient heat exchanger including corrugated heat exchanger panels provides enhanced heat transfer characteristics.

Abstract: A burner has a port facing into a combustion chamber along an axis. A secondary fuel injector structure has secondary fuel injection ports that face into the combustion chamber at locations spaced radially outward from the burner port. A tertiary fuel injector structure has tertiary fuel injection ports that face into the combustion chamber in directions perpendicular to the axis at locations spaced axially downstream from the secondary fuel injection ports.

Abstract: A lance for a hybrid burner of a combustor of a gas turbine, includes an inner passage for a liquid fuel, an outer passage coaxially enclosing the inner passage for a gaseous fuel, a plurality of star like arranged outer nozzles branching off radially from the outer passage, a plurality of inner nozzles, which branch off radially from the inner passage and which each extend coaxially inside one of the outer nozzles, and a distributor section, which is arranged upstream of the outer nozzles in the outer passage and has a plurality of star like arranged, coaxially extending through-openings for the gaseous fuel. In order to reduce the flow resistance in the gas path of the lance, the through-openings each have an opening width which is larger in the circumferential direction than in the radial direction.

Abstract: In a flame arrester arrangement which is formed from two metal strips (8, 9) which are wound together to form a disk having an approximately circular outer circumference and of which a first metal strip (8) is a smooth strip and the second metal strip (9) is a corrugated strip having defined corrugation, the two strips (8, 9), by bearing against one another, forming defined gaps (11) for passage of a fluid and being held in position, relative to one another by fixing pins inserted into radial bores (6), the radial bores (6) can be incorporated without deforming the gaps (11) even in the region of the bores (6) by virtue of the fact that the bores (6) are incorporated by spark erosion without deforming the corrugation formed in the second metal strip, such that the gaps (11) are also present in the region of the bores (6) in the manner defined by the corrugation.

Abstract: A burner arrangement includes a tubular mixing tube extending along an axis and configured to mix fuel and air, the mixing tube opening into a combustion chamber in a direction of flow; and a film air ring disposed in the mixing tube and arranged concentrically to the axis, the film air ring configured to prevent a backfiring of the fuel disposed in the mixing tube and to generate or reinforce an air film near the wall, wherein the film air ring has at least one annular gap concentric to the axis and configured to inject air.

Abstract: In a boiler furnace having nozzles for introducing combustion media such as air and coal, nozzle tip walls that have the greatest exposure to radiant heat and hot gases are provided with arrays of air holes that allow air to flow to the exposed sides of the walls from the opposite sides in order to reduce the temperature difference between the two sides and thereby reduce thermal distortion and damage resulting from oxidation.

Abstract: Heating provided by a burner that combusts hydrocarbon fuel can be provided at a sequence of different heat transfer rates by adjusting the total oxygen concentration of oxidant streams fed to the burner. A burner with which the method can be practiced is also disclosed.

Abstract: A burner assembly including a housing having an air inlet and a burner end, a motor, and an impeller mounted in the housing. The impeller is in fluid communication with the air inlet, in mechanical communication with the motor, and adapted to direct air from the air inlet towards the burner end of the housing. The burner assembly also includes at least one pre-mix gas injection nozzle mounted in the housing. Each of the at least one pre-mix gas injection nozzle has at least one orifice adapted to direct gaseous fuel into the housing. The burner assembly further includes a spin vane comprising at least one spin vane blade. The spin vane is mounted in the burner end of the housing and adapted to direct the flow of air in the burner end. The burner assembly still further includes a flattening screen located in the housing downstream from the impeller and an igniter mounted in the burner end of the housing.

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: The present invention provides a burner for manufacturing a porous glass base material that has small-diameter gas discharge ports and that achieves uniform linear velocity at the gas discharge ports, a uniform reaction, and a stable flame, and improved deposition efficiency.

Abstract: A flare apparatus for discharging and burning flare gas in the atmosphere is provided. The flare tip includes a flare gas conduit having a flare gas discharge opening and a combustion air conduit having a combustion air discharge opening. All of the flare gas to be flared is discharged through the flare gas discharge opening into a unified column of air discharged through the combustion air discharge opening. The flare gas discharge opening and the combustion air discharge opening are positioned with respect to one another such that flare gas discharged from the flare gas discharge opening is discharged inwardly into combustion air that is discharged from the combustion air discharge opening and admixed therewith. Essentially all of the discharged flare gas is admixed with discharged combustion air or external atmospheric air outside of the flare apparatus thereby preventing internal burning. A method of flaring a mixture of flare gas and combustion air is also provided.

Abstract: A burner system, for burning a liquid fuel/compressed air fuel mixture, comprising a discharge nozzle having a mixing chamber for mixing a liquid fuel with compressed air and discharging the fuel mixture via a discharge orifice. The burner system is coupled to a liquid fuel storage source for storing and supplying the liquid fuel, at a sight positive pressure, to the mixing chamber and the burner system also coupled to a source of compressed air which is supplied to the mixing chamber. An igniter is provided for igniting the fuel mixture, discharged from the discharge orifice in a substantially atomized form, for rapid and through combustion of the fuel mixture. Supplemental air is also supplied, via a variable speed supplemental airfan, to assist with complete combustion of the fuel mixture.

Abstract: A method for operating a fuel-fired furnace including at least one burner is provided. The method includes channeling a first fluid flow to the at least one burner at a first predetermined velocity, and channeling a second fluid flow to the at least one burner at a second predetermined velocity during a first mode of operation of the at least one burner. The second predetermined velocity is different than the first predetermined velocity.

Abstract: A direct flame impingement method and apparatus employing at least one multi-ported, internally recuperated burner. The burner includes an innermost coaxial conduit having a first fluid inlet end and a first fluid outlet end, an outermost coaxial conduit disposed around the innermost coaxial conduit and having a combustion products outlet end proximate the first fluid inlet end of the innermost coaxial conduit and a combustion products inlet end proximate the first fluid outlet end of the innermost coaxial conduit, and a coaxial intermediate conduit disposed between the innermost coaxial conduit and the outermost coaxial conduit, whereby a second fluid annular region is formed between the innermost coaxial conduit and the intermediate coaxial conduit and a combustion products annular region is formed between the intermediate coaxial conduit and the outermost coaxial conduit.

Abstract: A fuel nozzle for use in a burner comprises a main body having an inlet end and an outlet end and defining a longitudinal axis. A fuel passageway has a fuel receiving inlet, and a fuel emitting outlet for delivering fuel to a mixing chamber of the burner. A first air flow channel having an inlet, and an outlet disposed adjacent the fuel emitting outlet for delivering air to the mixing chamber. The portion of the first air flow channel adjacent the outlet is oriented obliquely to the longitudinal axis. A second air flow channel has an inlet, and an outlet disposed adjacent the fuel emitting outlet for delivering air to the mixing chamber. The first air flow channel and the second air flow channel generally surround the fuel passageway, and are disposed on the exterior of the main body.

Abstract: Provided is a solid fuel burner (60) suitable for controlling a flame to be formed by combustion of fuel ejected from the burner (60) and a temperature distribution in a furnace, a combustion apparatus using the solid fuel burner (60), and a method of operating the combustion apparatus. Providing in the fuel nozzle (10) a plurality of gas ejection nozzles (81), (82) and a restriction (obstacle) (19) downstream thereof, and ejecting a relatively large amount of gas from a portion of the gas ejection nozzles (81) provides a circumferential distribution in fuel concentration. Further, having the restriction (obstacle) (19) on a downstream side increases a deviation in fuel concentration. Providing a fuel concentration deviation in the circumferential direction makes it possible to change the forming position of a flame.

Abstract: A head assembly 52, 152 for a pulverized coal nozzle includes removeable wear-resistant inserts having vanes 54, 151, 153. The vanes 54, 151, 153 may be flat or curved to direct a stream of air and pulverized solid fuel particles from the inlet port 60, 160 toward the outlet port 62, 162. The curved vanes 151, 153 curve in two dimensions to evenly distribute the stream of air and pulverized solid fuel away from the outer surfaces reducing wear and corrosion. The pipe elbow has a removable cover 70, 170 that allows for easy access. The vanes are attached to a wear-resistant replaceable liner 185 thus allowing them to be easily removed and replaced. The wear-resistant liner 185 may be made from several parts 187, 189 for ease of removal and replacement.

Abstract: A heat transfer system and use thereof. The heat transfer system provides for the combustion of a fuel and the use of heat energy released by the combustion to heat a process fluid and to preheat the fuel and oxidant prior to their combustion. The heat transfer system includes three tubes with a fuel introduction tube surrounded by an oxidant introduction tube that is surrounded by a process tube. A heat transfer system having the appropriate geometry may provide for the flameless combustion of the fuel. The heat transfer system may also be integrated into other systems such as heat exchangers and catalytic process systems.

Abstract: A pilot burner (150, 350) for a gas turbine engine delivers an inner non-swirling fuel-oxidant mixture surrounded by an outer swirling fuel-oxidant mixture, thereby providing enhanced mixing with no recirculation zone. At least one fluid-restricting inlet port (166, 366) provides an oxidant to an inner mixing passage (160, 360). The inner mixing passage (160, 360) includes a plurality of fuel outlets (168). An outer annular mixing passage (180) receives oxidant from an upstream port (181) surrounding the inner mixing passage and includes at least one swirler element (186, 386) and fuel outlets (188).

Abstract: Slagging is prevented from occurring in a pulverized coal burner. A nozzle body 6, which is open to a furnace 1 and which injects pulverized coal together with primary air 14 transporting the coal to serve finally as combustion air, has an outer sleeve 8 and an inner sleeve 9 arranged in and coaxially of the sleeve 8. A fuel flow space 10 is formed between the sleeves 8 and 9. Straightening plates 29 are arranged on at least either of the sleeves 8 and 9 to project to the space 10 and extend axially of the nozzle body. The combustion air (primary air 14) carrying the pulverized coal passes through the space 10 and is injected.

Abstract: A burner includes separate fuel and oxidant conduits. The fuel conduit has inlet, transitional, and outlet sections, and the oxidant conduit has inlet and outlet sections. The cross sectional flow area of the fuel transitional section varies from an initial cross sectional flow area at the fuel intake to a different cross sectional flow area at the fuel outtake, and the cross sectional flow area of the fuel outlet section is substantially uniform. At least some of the oxidant inlet section is spaced around substantially all of at least a portion of at least one of the fuel inlet, transitional, and outlet sections. The cross sectional flow area of the oxidant outlet section is less than or equal to the cross sectional flow area of the oxidant inlet section and is substantially uniform, and at least some of it is spaced around substantially all of at least a portion of the fuel outlet section.

Abstract: A four-tube heating system for combusting a fuel and transferring the heat released therefrom to a process fluid. The heating system includes, a fuel introduction zone, a combustion zone, an oxidant introduction zone, and a process fluid zone, wherein the fuel introduction zone is defined by fuel introduction means for introducing fuel into the combustion zone that is defined by a reaction tube external to and surrounding the fuel introduction means, and wherein the oxidant introduction zone is defined by an oxidant introduction tube external to and surrounding the reaction tube, and wherein the process fluid zone is defined by a process tube external to and surrounding the oxidant tube.

Abstract: A burner capable of producing a low NOx emission combustion in the whole operating range, maintaining the flame at all times anchored to the diffuser body of the burner and without the use of systems, for example valves, with which to switch the introduction position of the reactants according to the temperature of the furnace. Such a burner is more flexible and cost-effective, both from a system point of view and from a control point of view, with respect to traditional burners.

Abstract: A burner system and method of operating a burner for reduced NOx emissions. The burner system comprises a flame stabilizer, at least one fuel staging lance, an actuated valve, a temperature sensor and a controller. The amount of fuel to the flame stabilizer relative to the amount of fuel to the fuel staging lances is controlled depending on furnace temperature and/or furnace production rate.

Abstract: A fuel injector for use in a furnace causes a primary stream of a carrier gas and fuel to be mixed with heated air, oxygen or a mixture of oxygen and CO2 or re-circulated flue gas, within the injector by a secondary stream of heated air, before the primary stream exits the injector as a fuel stream and flows into a combustion zone of the furnace. The interaction of the primary stream with the heated air of the secondary stream increases stoichiometry at the center of the fuel stream exiting the injector, so as to minimize NOx creation and maximize combustion of fuel in the furnace.

Abstract: An assembly is provided for purifying toxic gases from production processes by thermal conversion in a reactor chamber and subsequent treatment of reaction products with a sorption agent in a washing device in order to bind water-soluble reaction products and to elute solid reaction products. The reactor chamber has an external wall and an internal wall, the internal wall tapering at its base in the form of a funnel at a predetermined angle. A unit for thermal treatment of toxic gases is located on the reactor chamber, sealing the top of the chamber. An inner face of the internal wall of the reactor chamber comprises a film of water flowing downwards in a uniform manner. The exterior of the internal wall is surrounded by a cloak of water. A waste gas outlet and a connection for a water circuit are located at the lower end of the tapering internal wall.

Abstract: The present invention is a method of combustion of a solid fuel stream with oxygen. The present invention includes introducing a first stream, comprising a first portion of substantially pure oxygen, into a first conduit. The present invention includes introducing a second stream, comprising a solid fuel stream and a conveying media, into a second conduit, wherein the second conduit is concentric with, and surrounding, the first conduit. The present invention includes introducing a third stream, comprising a second portion of substantially pure oxygen, into a third conduit, wherein the third conduit is concentric with, and surrounding, the first conduit and the second conduit. The present invention includes igniting the first stream, the second stream, and the third stream as they exit the first conduit, the second conduit and the third conduit, in such a way as to create a flame.

Abstract: The burner preferably exclusively burns substantially explosible solid fuels and preferably has instant ON-OFF thermostat control, wastes no energy preheating the enclosure or external air supply, achieves stable combustion the moment the powder-air mix is ignited in our burner, is used in the upward vertical mode except for oil burner retrofits, burns a solid fuel in a single-phase regime as if it were a vaporized liquid or gas, is designed to complete combustion within the burner housing itself rather than in a large, high temperature furnace enclosure which it feeds, has an ultra-short residence time requirement, is a recycle consuming burner with self-contained management of initially unburned particles, is much smaller, simpler and lower cost, has a wider dynamic range/turndown ratio, is more efficient in combustion completeness and thermal efficiency, and operates with air-fuel mix approximately at the flame speed.

Abstract: An animal and vegetable oils combustor, wherein primary air is introduced into a burner tile in the form of straight-ahead air flow moving straight ahead along the axial direction of the burner tile and secondary air is introduced in the form of swirl air flow moving along the inner surface of the side wall of the burner tile, whereby perfect combustion is liable to occur since a centrifugal force acts on liquid-drop fuel by swirl air flow to diffuse the fuel in the radial direction and the liquid-drop fuel does not take such a route as to be adhered to the inner wall even if char is included in the liquid drop fuel since the fuel is jetted after the grain size thereof is adjusted to small one beforehand.

Abstract: Heating provided by a burner that combusts hydrocarbon fuel can be provided at a sequence of different heat transfer rates by adjusting the total oxygen concentration of oxidant streams fed to the burner. A burner with which the method can be practiced is also disclosed.

Abstract: A method for burning gas in a burner, including leading the gas through an inner fuel tube (13) and introduction of combustion air through an annular space surrounding the inner fuel tube. This space forms of an outer tube (11) terminated by a conically converging section, wherein the end of the inner fuel tube forms a burner head (15). The major part of the primary gas is introduced into the upstream end of the burner head, to go into the combustion air that flows past the burner head, whereas a smaller part of a secondary gas is introduced into the free end of the burner head (15) and into the constricted part of the annular channel that surrounds the burner head. The gas flow is accelerated past the burner head due to the reducing cross section and is burned downstream in relation to the burning head, wherein the mixture has properties that reduces the formation of Nox at the same time as the combustion becomes complete. It is also described a burner for performing this method.

Abstract: A burner assembly has a burner head and a deflector plate extending radially therefrom and across a firetube housing for supporting the burner assembly therein. The deflector plate has a plurality of angled vanes for re-directing secondary combustion air flowing through the housing. Secondary air is deflected away from a nozzle tip at the burner head to minimize lifting of the flame by the deflector plate or by a low pressure ring formed around the nozzle tip above the deflector plate for creating an area of low pressure. Preferably, a combination of the deflector plate and low pressure ring provides a stable flame positioned at the nozzle tip under low-fire and high-fire conditions enabling use of a pilotless ignition and flame sensing system which is consistent under low and high fire conditions. More preferably, the deflector plate supports the igniter and optionally a heat return tube for heat tracing of the freeze-prone burner assembly components.

Abstract: A solid-fuel burner comprising a fuel nozzle for injecting a mixed fluid with a mixture of solid fuel and air as a carrier gas thereof, a plurality of air nozzles provided on the outside of the fuel nozzle for surrounding the fuel nozzle; an end portion of an inner circumferential wall of the air nozzle located at least at the outermost circumference is outwardly expanded, and an inductive member provided at outlet of the air nozzle located at least on the outermost circumference so as to direct flow of air in the direction of outer circumference.

Abstract: Heating provided by a burner that combusts hydrocarbon fuel can be provided at a sequence of different heat transfer rates by adjusting the total oxygen concentration of oxidant streams fed to the burner. A burner with which the method can be practiced is also disclosed.

Abstract: A low emissions burner includes a diffusion burner surrounded by an annular array of premix burners. The diffusion burner operates at maximum swirl air flow and at a low constant fuel rate to reduce NOx emissions. The diffusion burner provides a stable swirling diffusion flame. An annular array of premix burners surrounds the diffusion burner and provides a non-swirling premix flame about the diffusion flame to advantageously provide a higher heat content about the periphery of the burner flame to facilitate industrial drying processes using the burner. The diffusion burner flame maintains the premixed flame stabilized. Water injection nozzles are provided each of the premix and diffusion burners.

Abstract: A method and apparatus for preheating a furnace during a warm-up phase of furnace operation. The furnace has main burners with a tubular fuel supply surrounded by a main combustion air duct defining an annular space between the supply and the duct that extends in an axial direction of the main burner. A pilot nozzle in the annular space extends in an axial direction of the burner towards an interior of the furnace and discharges readily ignitable fluid fuel jets through orifices in the nozzle toward the interior of the furnace. Combustion air from the duct is directed past the nozzle and is mixed with the fuel discharged from the orifices to form an ignitable mixture that is ignited to form the furnace heating pilot flame downstream of the nozzle.

Abstract: A method for oxy-fuel combustion, the method comprising the steps of: introducing a liquid fuel into an emulsion chamber through a liquid fuel conduit having an effective diameter, the emulsion chamber having a length that is 2 times or less than 2 times of said effective diameter of said liquid fuel conduit; introducing an atomizing gas into the emulsion chamber through at least one atomizing gas conduit; mixing the liquid fuel and the atomizing gas in said emulsion chamber to create an emulsion mixture that has a mean residence time in said emulsion chamber of from 500 to 800 ?s, the emulsion mixture having an emulsion mixture velocity less than or equal to 12 m/s; and discharging said emulsion mixture through a generally rectangular-shaped orifice into an oxygen-enriched oxidizer stream. A nozzle and burner for oxy-fuel combustion are also disclosed.

Abstract: Emissions of NOx and CO are reduced from combustion devices such as coal-fired furnaces by increasing the stoichiometric ratio of burner(s) having a lower average temperature and increasing the stoichiometric ratio of burner(s) having a higher average temperature.

Abstract: A burner for a combustor of a turbogroup is provided. The burner includes a burner body, an outlet flange, and a plenum which is exposed, or can be exposed, to admission of cooling medium. In order to improve the cooling of the outlet flange, a flow passage and a supply passage are formed. The flow passage and the supply passage are arranged so that the cooling medium from the plenum enters the flow passage, is transferred from the flow passage into the supply passage, and is discharged from the supply passage through holes into a burner interior.

Abstract: Apparatus is described for combusting exhaust gases output from a plurality of process chambers. The apparatus comprises a plurality of exhaust gas combustion nozzles (22) connected to a combustion chamber (24). Each nozzle receives a respective exhaust gas (26), and comprises means for receiving a fuel (40) and an oxidant (30) for use in forming a combustion flame within the chamber. A controller receives data indicative of the chemistry of the exhaust gas supplied to each nozzle, and adjusts the relative amounts of fuel and oxidant supplied to each nozzle in response to the received data. This can enable the nature of each combustion flame to be selectively modified according to the nature of the exhaust gases to be destroyed by that flame, thereby enhancing the destruction rate efficiency of the exhaust gas and optimising fuel consumption.

Abstract: A new burner apparatus and method of combusting fossils fuels for commercial and industrial application is provided wherein the new burner apparatus achieves low NOx emissions by supplying oxygen to the center of the burner flame in as manners so as to create a fuel rich internal combustion zone within the burner flame.

Abstract: A feed injector for use in a gasification apparatus comprising plural concentric tubes converging at an outlet tip, at least one interior tube of the plural concentric tubes having a plurality of static, helically-twisted mixing elements fixed to an exterior surface thereof.

Abstract: A burner has a port facing into a combustion chamber along an axis. A secondary fuel injector structure has secondary fuel injection ports that face into the combustion chamber at locations spaced radially outward from the burner port. A tertiary fuel injector structure has tertiary fuel injection ports that face into the combustion chamber in directions perpendicular to the axis at locations spaced axially downstream from the secondary fuel injection ports.

Abstract: A burner includes separate fuel and oxidant conduits. The fuel conduit has inlet, transitional, and outlet sections, and the oxidant conduit has inlet and outlet sections. The cross sectional flow area of the fuel transitional section varies from an initial cross sectional flow area at the fuel intake to a different cross sectional flow area at the fuel outtake, and the cross sectional flow area of the fuel outlet section is substantially uniform. At least some of the oxidant inlet section is spaced around substantially all of at least a portion of at least one of the fuel inlet, transitional, and outlet sections. The cross sectional flow area of the oxidant outlet section is less than or equal to the cross sectional flow area of the oxidant inlet section and is substantially uniform, and at least some of it is spaced around substantially all of at least a portion of the fuel outlet section.

Abstract: A burner for producing a plug-like flow and low NOx emissions. The burner has a central air jet and plural staged fuel jets surrounding the central jet. The ratio of the sum of the momentums of vector components of the staged jets along respective axes parallel to the central longitudinal axis of the central jet to the momentum of the central jet along that axis is within the range of 0.5 to 1.5 and most preferably 0.8.