A combustion apparatus includes a housing and injection members. The housing has a bottom wall and side walls which enclose a combustion chamber having an opening at the top. The injection members are arranged on two side walls opposite each other and include at least one first injector and at least one second injector. The first injector supplies to the combustion chamber a mixture having a first-part oxidant and a combustible gas, with the volume percentage of the combustible gas in the mixture being greater than an upper combustion limit of the combustible gas. The second injector supplies a second-part oxidant to the combustion chamber. The total amount of the first-part oxidant and the second-part oxidant supplied to the combustion chamber reach stoichiometric balance with the amount of the combustible gas supplied to the combustion chamber. The combustion apparatus can produce short flames with high safety and good stability.

A ground supported single drum power boiler is described combining a refractory lined and insulated V-Cell floor; refractory lined and insulated combustion chamber; integrated fuel chutes configured to pre-dry wet solid fuel; top mounted fuel bin; internal chamber walls; configurable combustion air systems; and a back pass with after-burner ports and cross flow superheaters. The boiler can be configured in pre-assembled modules to minimize the field construction time and cost. An alternative embodiment is adaptable as a gasifier.

A burner apparatus for a fired-heater system and a method of burner operation wherein the burner fuel is ejected outside of the burner wall from a surrounding fuel discharge ring, or from a lateral elongate ejection bar in the case of a flat flame burner, to a combustion zone projecting from the forward end of burner wall. The burner apparatus and method reduce NO.sub.x production by a combination of enhanced internal flue gas recirculation and staged fuel operation.

A combustion chamber may include a first surface and a second surface interconnected by a wall forming a chamber having a central axis. The first surface may define an exhaust opening and the second surface defining a pilot opening, wherein the exhaust opening and the pilot opening align along the central axis. A plurality of inlet ports may be configured to deliver air to the chamber. A plurality of fuel ports may be arranged on an inside of the second surface to deliver fuel to the chamber. The air flow from the inlet ports and fuel from the fuel ports may oppose each other to create a vortex of product proximal to the second surface.

A method for heating a heating chamber to a temperature below the spontaneous ignition temperature of the fuel that is used, wherein fuel and air are reacted in flameless oxidation in a non-stoichiometric mixture ratio in a combustion chamber. The air ratio is at least lower than the stoichiometric ratio =1 such that the temperature in the combustion chamber does not exceed the temperature at which thermal nitrous oxide generation begins. Otherwise, is established such that the spontaneous ignition temperature of the fuel is exceeded. This results in two permissible air ratio ranges, between .sub.min and .sub.1 in sub-stoichiometric operation, and .sub.2 to .sub.max in superstoichiometric operation of the combustion chamber. The still-reactive gases released from the combustion chamber are made to react in the heating chamber, preferably by flameless oxidation. This avoids thermal nitrous oxide generation in the heating chamber.

A ground supported single drum power boiler is described combining a refractory lined and insulated V-Cell floor; refractory lined and insulated combustion chamber; integrated fuel chutes configured to pre-dry wet solid fuel; top mounted fuel bin; internal chamber walls; configurable combustion air systems; and a back pass with after-burner ports and cross flow superheaters. The boiler can be configured in pre-assembled modules to minimize the field construction time and cost. An alternative embodiment is adaptable as a gasifier.

A method of controlling the operation of an oxy-fired boiler includes combusting a fuel that comprises oil heavy residues in a boiler, the oil heavy residues including hydrocarbon molecules having a number average molecular weight from approximately 200 to approximately 3000 grams per mole, discharging flue gas from the boiler, recycling a portion of the flue gas to the boiler, combining a first oxidant stream with the recycled flue gas to form a combined stream, splitting the combined stream into a plurality of independent split streams, introducing each independent split stream at a different elevation of the boiler, and controlling independently a parameter of each of the independent split streams to adjust the heat release at each respective elevation of the boiler to vary the heat release profile of the boiler by adding a second oxidant stream to each respective independent split stream to form respective independent oxygen enriched split streams.

A device for stabilizing dilute combustion for use in a cold-walls type combustion chamber comprises a burner. The burner comprises at least one oxidant inlet and at least one fuel inlet. The oxidant and fuel inlets opening separately into the chamber at a distance suitable for establishing combustion which is highly diluted by internal re-circulations of combustion products toward a burner zone. The device comprises a heating element configured to heat, during steady operating conditions, the combustion products to sustain self-ignition conditions. The heating element is positioned in a dilution zone and surrounds a set of oxidant and fuel jets.

A method for reducing nitrogen oxide NOx emissions during combustion of a gaseous fuel in a burner intended for a naked-flame or controlled-atmosphere reheating furnace, for reheating steel products or for continuous coating and/or annealing of metal strips, wherein a first dilution is carried out by mixing combustion air with combustion products upstream from or in the body of the burner, and a second dilution is carried out directly at the level at which the gaseous fuel reacts with the combustion air, mixing the fuel with a recirculated portion of the flame or products of partial combustion, the double dilution enabling the physical and chemical properties of the gas to be modified in order for the burner to operate with low oxygen rates and obtain a flame that produces a very low level of NOx production regardless of the temperature of the enclosure in which the combustion takes place.

A fuel-fired burner includes a combustion air inlet for receiving combustion air coupled to a combustion air nozzle at an input to a second chamber within a burner housing spaced apart from a third chamber within the second chamber. The combustion air nozzle directs the combustion air into the third chamber. A fuel inlet coupled to a burner nozzle secured to a burner mounting plate has a recycle port for receiving hot exhaust gas provided to an exhaust gas path. A jet pump located entirely inside the burner housing is configured to receive the hot exhaust gas from the exhaust gas path. The jet pump operates by flowing the combustion air through the combustion air nozzle which suctions in the hot exhaust gas through the recycle port into the exhaust gas path then into a gas mixing zone for mixing the hot exhaust gas and the combustion air.