Low NOx and low Co burner and method for operating same

摘要

A round burner capable of being operated with reduced CO and NOx emissions includes a venturi tube positioned to direct a flow of air through the burner and into a combustion zone in a combustion chamber through an entrance in a wall of the combustion chamber. The venturi tube has inlet and outlet ends and a throat. The outlet end of the venturi tube has a larger internal diameter than either the inlet end or the throat and the same is positioned adjacent the entrance to the combustion chamber. The inlet end of the venturi tube is also positioned further from the entrance than the outlet end of the venturi tube. The burner may include a duct system that includes an inlet disposed in fluid communication with the combustion zone and an outlet disposed in fluid communication with the venturi tube adjacent the throat thereof. The system is arranged and adapted to recirculate a stream of flue gas from a location within said combustion chamber adjacent the combustion zone by induction into the venturi tube at a low pressure location adjacent the throat of the venturi tube so that the recirculated stream of internal flue gas is inducted into and intermixed with the flow of air at the throat of the venturi tube. Alternatively or cumulatively, the burner may include a fuel gas injector arrangement having an injector nozzle extending through the wall at a location adjacent the combustion zone. The injector nozzle is in fluid communication with the combustion chamber and is positioned to direct a flow of fuel gas into the combustion chamber at a location in the wall radially beyond the inner edge of the entrance. Also disclosed is a method for operating the burner to reduce CO and NOx emissions.