Patent ID: 8689707

Claim:
A replacement burner system which facilitates reduction in an amount of nitrous oxide produced during combustion of a fuel, the replacement burner system capable of providing five concentric and distinct flow paths for fuel and combustion air, comprising: a fuel supply duct having an inlet and an outlet and a bend located between the inlet and the outlet; a fuel deflector located within the fuel supply duct, between the bend and the outlet, to facilitate redistribution of a flow of the fuel; a coal nozzle located within the fuel supply duct between the fuel deflector and the outlet, and a position of the coal nozzle being adjustable along a length of the fuel supply duct, wherein the coal nozzle comprises an innermost central zone which induces a swirling flow pattern of the fuel as the fuel flows therethrough and a radially outermost peripheral zone which facilitates supply of the fuel in a substantially linear flow pattern in an outer fuel zone concentric with and surrounding the central zone; an exterior surface of the fuel supply duct supporting an air swirling device, and the air swirling device occupying between about 65% to about 75% of the transverse cross sectional flow area, located between an exterior surface of the fuel supply duct and the inwardly facing surface of a venturi register, after the replacement burner system is accommodated within a windbox of a combustion boiler; wherein the air swirling device is located between an exterior surface of the fuel supply duct and the inwardly facing surface of the venturi register, and comprises a first radially innermost combustion air zone, concentric with and surrounding the exterior surface of the fuel supply duct to supply air with a substantially linear flow pattern; and an intermediate combustion air zone, concentric with and surrounding the first radially innermost combustion air zone to supply air substantially in a swirling flow pattern, and a radially outermost combustion air zone to supply air in a linear flow pattern zone concentric with and surrounding the intermediate combustion air zone.