PREMIXED/HIGH-VELOCITY FUEL JET LOW NO X BURNER

The invention is a process for combusting a gaseous fuel in a burner to result in low NO x emissions by first feeding a gaseous fuel stream and an air stream to a premixer where the fuel and air streams are mixed to form a fuel-air mixture. The fuel and air streams are fed to the premixer at a fuel to air equivalence ratio of less than 1 (i.e., fuel-lean). Second, the fuel-air mixture is passed to a combustion chamber where the fuel is substantially combusted to produce a combustion chamber jet and flue gases. The combustion chamber jet and flue gases pass into a heating zone which may include a furnace, heater, or boiler. Third, at least two high-velocity fuel streams, optionally diluted with a non-reactive thermal ballast, are passed to the heating zone contemporaneously with the second step. The high-velocity fuel streams entrain at least a portion of the flue gases. The fuel in the high-velocity fuel streams is partially combusted prior to coming into contact with the combustion chamber jet. Last, the flue gases are removed from the heating zone.