Abstract: A burner nozzle for delivering fuel to a burner flame in a furnace includes an inner cylinder and an outer cylinder that are both hollow. The inner cylinder is at least partly disposed within the outer cylinder and axially aligned with it, and is movable in an axial direction relative to the outer cylinder. One end of the inner cylinder has at least one outward projection extending in a radial direction from the outer surface of the cylinder, this projection serving to decrease the free cross-sectional area between the inner cylinder and the outer cylinder at that end of the inner cylinder.

Abstract: A burner nozzle for delivering fuel to a burner flame in a furnace includes an inner cylinder and an outer cylinder that are both hollow. The inner cylinder is at least partly disposed within the outer cylinder and axially aligned with it, and is movable in an axial direction relative to the outer cylinder. One end of the inner cylinder has at least one outward projection extending in a radial direction from the outer surface of the cylinder, this projection serving to decrease the free cross-sectional area between the inner cylinder and the outer cylinder at that end of the inner cylinder.

Abstract: A tangential fired boiler has a circumferential wall defining a combustion zone and a plurality of fuel inlets disposed along the circumferential wall. The plurality of fuel inlets inject fuel at non-uniform rates in order to produce localized fuel rich, oxygen poor zones and fuel lean, oxygen rich zones within the combustion zone, and to cause ambient boiler gases to be entrained into and mix with the oxygen poor zone to achieve fuel staging of the boiler.

Abstract: A damper assembly for adjusting a full flow of the air-entrained coal traversing at least one annular conduit along a flow path, wherein the one conduit has a peripheral wall defining the entire cross-sectional area of the conduit, the damper assembly includes an elongated blade, which has its length substantially greater than its width and which is rotatably mounted to the conduit to adjust the flow from no change to approximately 75% of the full flow.

Abstract: A method and apparatus are described for reducing NO.sub.x in a combustion zone such as a boiler by spatially selectively injecting a cooling fluid into the combustion zone so that the fluid is entrained to intersect an identifiable NO.sub.x producing zone. The cooling fluid can be water or a gas or mixture of them and whose temperature is sufficiently low or whose combined mass flow and temperature are sufficiently low so that the cooling fluid can reach the NO.sub.x producing zone and cool it to a temperature where the NO.sub.x production is significantly reduced. In one embodiment of the invention a cyclone boiler has a number of identifiable NO.sub.x producing zones. Several of these are targeted by spatially distinct cooling fluid streams placed at strategic locations.