A device heating a fluid and usable in a rocket launcher to pressurize a liquefied propellant. The device includes a first burner performing first combustion between a limiting propellant and an excess propellant; a first heat exchanger in which first burnt gas from the first combustion transfers heat to the fluid; at least one second burner into which both the first burnt gas and some limiting propellant are injected to perform second combustion between the limiting propellant and at least a portion of unburnt excess propellant present in the first burnt gas. The second burnt gas from the second combustion flows through a second heat exchanger to transfer heat to the fluid. Burnt gas from each combustion flows in respective burnt gas tubes within a common overall heat exchanger including the heat exchange units, the gas transferring heat to the fluid, the fluid flowing between the burnt gas tubes.

A burner assembly combines oxygen and fuel to produce a flame. The burner assembly includes an oxygen supply tube adapted to receive a stream of oxygen and a fuel supply tube arranged to extend through the oxygen tube to convey a stream of fluidized, pulverized, solid fuel into a flame chamber. Oxygen flowing through the oxygen supply tube passes through oxygen-injection holes formed in the fuel supply tube and then mixes with fluidized, pulverized, solid fuel passing through the fuel supply tube to create an oxygen-fuel mixture in a downstream portion of the fuel supply tube. This mixture is discharged into the flame chamber and ignited in a flame chamber to produce a flame.

Clean combustion and equilibration equipment and methods are provided to progressively deliver, combust and equilibrate mixture of fuel, oxidant and aqueous diluent in a plurality of combustion regions and in one or more equilibration regions to further progress oxidation of products of incomplete combustion, in a manner that sustains combustion while controlling temperatures and residence times sufficiently to reduce CO and NOx emissions to below 25 ppmvd, and preferably to below 3 ppmvd at 15% O.sub.2.

The invention relates to a burner, particularly Low-NO.sub.X-burner, for generating a flame by combustion of a fuel, comprising: a tile (15, 15a, 15b) surrounding an opening (2, 2a, 2b) of the tile (15, 15a, 15b) extending along a burner axis (12), the tile (15, 15a, 15b) further comprising a front side (20) and a rear side (21) facing away from the front side (20), wherein the rear side (21) comprises an air inlet (10, 10a, 10b) connected to said opening for feeding air (A, A′, A″) into said opening (2, 2a, 2b), and wherein said front side (20) comprises a discharge outlet (9, 9a, 9b) connected to said opening (2, 2a, 2b) for discharging a flame (30) generated by the burner (1) into a surrounding area (S), and wherein the tile (15, 15a, 15b) further comprises an inside (22) facing said opening (2, 2a, 2b) as well as an outside (23) facing away from said opening (2, 2a, 2b). According to the invention the burner (1) further comprises at least one oxygen lance (5) extending along the burner axis (12) in a first recess (17) of said tile (15, 15a, 15b), the at least one oxygen lance (5) having an ejection nozzle (6) at an end region of the at least one oxygen lance (5) for ejecting oxygen (O), particularly such that the oxygen (O) is at first ejected into a colder flue gas region (31) surrounding the relatively hotter flame (30) generated by the burner (1). Further, the invention relates to a method for generating a flame (30).

A process for operating a heater that can be operated with hydrocarbon fuel, especially for a vehicle includes providing a substoichiometric air/fuel mixture in a precombustion chamber (18) for a combustion operation and performing a cold flame combustion in the precombustion chamber (18). The precombustion products forming in the precombustion chamber (18) during the cold flame combustion are supplied to a catalyst arrangement (32) and a partial catalytic oxidation is performed for producing a gas containing hydrogen and carbon monoxide. The gas produced during the partial catalytic oxidation is supplied to a main combustion chamber (34) for producing a hydrogen/carbon monoxide/air mixture. The hydrogen/carbon monoxide/air mixture is burned in the main combustion chamber (34).

A process for operating a heater that can be operated with hydrocarbon fuel, especially for a vehicle includes providing a substoichiometric air/fuel mixture in a precombustion chamber (18) for a combustion operation and performing a cold flame combustion in the precombustion chamber (18). The precombustion products forming in the precombustion chamber (18) during the cold flame combustion are supplied to a catalyst arrangement (32) and a partial catalytic oxidation is performed for producing a gas containing hydrogen and carbon monoxide. The gas produced during the partial catalytic oxidation is supplied to a main combustion chamber (34) for producing a hydrogen/carbon monoxide/air mixture. The hydrogen/carbon monoxide/air mixture is burned in the main combustion chamber (34).

A gas furnace includes a mixing pipe through which a mixture formed by mixing fuel gas and air flows; a burner assembly that generates combustion gas by burning the mixture that passed through the mixing pipe; and a heat exchanger through which the combustion gas flows. In this case, the burner assembly includes a burner in which flame generated when the mixture is burned is seated; and a mixing chamber that mediates delivery of the mixture from the mixing pipe to the burner, thereby significantly reducing NOx emission.

A gas furnace includes a mixing pipe through which a mixture formed by mixing fuel gas and air flows; a burner assembly that generates combustion gas by burning the mixture that passed through the mixing pipe; and a heat exchanger through which the combustion gas flows. In this case, the burner assembly includes a burner in which flame generated when the mixture is burned is seated; and a mixing chamber that mediates delivery of the mixture from the mixing pipe to the burner, thereby significantly reducing NOx emission.

A dry low NO.sub.X staged combustion system includes a fuel nozzle and a combustion compartment. The fuel nozzle includes a purge gas tube, a diffusion combustion fuel tube, an isolation gas tube, a premixed combustion fuel tube, a premixed combustion air tube. The purge gas tube is configured to feed a purge gas. The diffusion combustion fuel tube is fitted over the purge gas tube, and having an end provided with a diffusion combustion fuel swirler. The isolation gas tube is fitted over the diffusion combustion fuel tube. The premixed combustion fuel tube is fitted over the isolation gas tube. The premixed combustion air tube is fitted over the premixed combustion fuel tube. The combustion compartment is located downstream of the fuel nozzle.

The invention relates to a method of making a mineral melt, the method comprising providing a circulating combustion chamber which comprises an upper zone, a lower zone and a base zone, injecting primary particulate fuel and particulate mineral material and primary combustion gas into the upper zone of the circulating combustion chamber, thereby at least partially combusting the primary particulate fuel and thereby melting the particulate mineral material to form a mineral melt and generating exhaust gases, injecting into the lower zone of the circulating combustion chamber, through at least one first burner, secondary combustion gas and gaseous fuel and secondary particulate fuel, wherein the secondary combustion gas and gaseous fuel and secondary particulate fuel are injected via a single first burner, wherein the amount of secondary combustion gas injected via each first burner is insufficient for stoichiometric combustion of the total amount of gaseous fuel and secondary particulate fuel injected via that first burner, and injecting tertiary combustion gas into the lower zone of the circulating combustion chamber, through at least one tertiary combustion gas injector, whereby the tertiary combustion gas enables completion of the combustion of the gaseous fuel and the secondary particulate fuel, separating the mineral melt from the hot exhaust gases so that the hot exhaust gases pass through an outlet in the circulating combustion chamber and the mineral melt collects in the base zone. The invention also relates to apparatus suitable for use in the method.