Abstract: A method and apparatus for reducing NO.sub.x emissions in a gas burner in which the burner includes a burner supply for supplying fuel gas and primary air to the furnace and projecting the fuel gas into the furnace, a secondary air supply for supplying secondary air to the burner, and a recirculating device for mixing the secondary air with the spent gases inside the furnace, which is then recirculated and combusted to reduce NO.sub.x gases. The method of the invention includes the steps of supplying fuel gas and primary air to the furnace, projecting the fuel gas into the furnace, combusting the fuel gas and primary gas to produce spent gases, supplying secondary air to the furnace, mixing the secondary air with the spent gases inside the furnace to produce diluted air, and recirculating and combusting the diluted air with the fuel gas and primary air to reduce NO.sub.x emissions.

Abstract: Method and apparatus for mixing gases while providing a substantially constant gas-to-gas ratio while increasing or decreasing the flow of the mixture, wherein the flows of gases introduced into the mixing step are turbulent and have a Reynolds number of above about 2000.

Abstract: A low NOx gaseous fuel burner that creates a wall hugging flame, even in a cup. It is comprised of two staged premix units, one unit, in a cup, running very lean and the second unit, extended into the furnace, running very rich, the combination being stoichiometric.

Abstract: A staged, superposition gaseous fuel burner provides substantial reduction of nitrogen oxide content in the combustion gases by providing a transverse turning plate in the burner tip and by staging the delivery rich combustion gases, by introducing premix gaseous fuel in stages spaced with respect to incoming secondary air, thereby exposing the incoming secondary air to spaced stages of the rich mixture.

Abstract: A gaseous fuel burner provides substantial reduction of nitrogen oxide content in the combustion gases by creating a screen of premix combustion products, by introducing secondary gaseous fuel for admixture with the screen, and by exposing secondary air to the mixture for reaction with the secondary gaseous fuel.

Abstract: A single regenerative coke oven battery is constructed and operated as a plurality of individual and separate groups of heating walls, each group capable of independent reversal and heating cycles. During slow-down operations, one or more of the individual groups of heating walls is shut down for a preselected time period, with no flow of combustion air, fuel and waste gas in the heating walls, while the remainder of the groups are operated at substantially full air and gas flow. The battery is capable of a slow-down operation while avoiding uneven coking and variations in the amount of byproduct coke oven fuel gas generated.

Abstract: A coke oven and method of heating a coke oven are provided in which the coke oven has coking chambers with a low burner heating wall on one side of the coking chamber and a high burner heating wall on the other side of the coking chamber. Heating takes place by only low burners in one heating wall and only high burners in the other heating wall.