A method of operating a combustion burner to heat a furnace. Fuel and combustion air are supplied into a combustion zone and ignited. Additional combustion air is supplied into the atmosphere outside of the combustion zone. The amount of additional combustion air supplied outside of the combustion zone is decreased as a temperature of the atmosphere inside the furnace increases such that the content of nitrogen oxides (NOx), as corrected for 3% O.sub.2 (cNOx (3% O.sub.2)), in the gases generated by combustion of the fuel and the combustion air and emitted from the furnace maintained below a predetermined value.

A method of operating a combustion burner to heat a furnace. Fuel and combustion air are supplied into a combustion zone and ignited. Additional combustion air is supplied into the atmosphere outside of the combustion zone. The amount of additional combustion air supplied outside of the combustion zone is decreased as a temperature of the atmosphere inside the furnace increases such that the content of nitrogen oxides (NOx), as corrected for 3% O.sub.2 (cNOx (3% O.sub.2)), in the gases generated by combustion of the fuel and the combustion air and emitted from the furnace maintained below a predetermined value.

A method of forming a gas turbine engine component, the method including forming a plurality of cooling apertures in a preform structure of the component, the plurality of cooling apertures of the preform structure comprising a first cooling aperture and a second cooling aperture, wherein cross-sectional shapes of the first and second cooling apertures of the preform structure are different from one another, as measured in a same relative plane; and applying a coating to at least a portion of the preform structure to form the component, wherein a cross-sectional shape of the first and second cooling apertures of the component are approximately the same as one another, as measured in the same relative plane.

A method of forming a gas turbine engine component, the method including forming a plurality of cooling apertures in a preform structure of the component, the plurality of cooling apertures of the preform structure comprising a first cooling aperture and a second cooling aperture, wherein cross-sectional shapes of the first and second cooling apertures of the preform structure are different from one another, as measured in a same relative plane; and applying a coating to at least a portion of the preform structure to form the component, wherein a cross-sectional shape of the first and second cooling apertures of the component are approximately the same as one another, as measured in the same relative plane.

A method is provided for heating a furnace arranged with a heating zone heated with a burner providing a flame extending in a longitudinal direction and fed with a fuel and a primary oxidant, the burner is operated with a mass relationship between the fed fuel and primary oxidant permitting less than 50% of the fed fuel to be combusted using the primary oxidant, and a respective pair of secondary oxidant lances are provided one either side of the furnace pointing into the heating zone, lancing a secondary oxidant into the heating zone downstream of the burner substantially parallel with a cross plane, such that a temperature is measured downstream of the lances and that each of the lance pairs includes an upstream, low-speed first and a downstream, high-speed second lance, wherein the amount of secondary oxidant supplied via the first lance is regulated to achieve a homogenous lateral temperature profile. A related furnace is also provided.

Nozzles for delivering air into a combustion system of a boiler utilizing an interchangeable divided nozzle barrel along with a variable vane. The vane can be rotated to different divisions in the nozzle to change the size of the outlet flow area and subsequently the flow velocity of the air into the combustion system to optimize performance and adjust for changes in load and fuel.

A combustion apparatus includes a burner and a heat shield plate. The heat shield plate includes a main plate portion located on a lateral side of a flame formation region above the burner to erect, a stepped portion protruding from a lower end of the main plate portion toward the burner and set at approximately the same height as that of a flame hole surface of the burner, and air passage holes provided in the stepped portion. The main plate portion is provided with a facing wall portion which protrudes from a middle part of the main plate portion in a vertical height direction thereof toward the flame formation region and faces the air passage holes so as to be subjected to a collision with air travelling upward from the air passage holes. This configuration allows the heat shield plate to be properly cooled/protected, while reducing consumed air.

A nozzle in a burner assembly is configured to produce a flame. The nozzle is configured to include a fuel-discharge outlet and to conduct fuel along a path in the nozzle to the fuel-discharge outlet. Pressurized primary oxygen is provided to mix with fuel discharged by the nozzle to produce a mixture that can be ignited to produce a flame. Staged oxygen is provided to the flame in a region downstream from the nozzle.

A nozzle in a burner assembly is configured to produce a flame. The nozzle is configured to include a fuel-discharge outlet and to conduct fuel along a path in the nozzle to the fuel-discharge outlet. Pressurized primary oxygen is provided to mix with fuel discharged by the nozzle to produce a mixture that can be ignited to produce a flame. Staged oxygen is provided to the flame in a region downstream from the nozzle.

The present application provides a tangentially fired boiler. The tangentially fired boiler may include a combustion chamber and an overfire air system positioned about the combustion chamber. The overfire air system may include a number of overfire air windboxes positioned in a horizontal orientation.