Combined oxygen blowing/fuel burner lance assembly

Abstract

An improved oxygen blowing/fuel burner lance assembly for introducing, at selected times, a flow of oxygen and/or carbonaceous fuel material, such as fine-grained carbon or hydrocarbon gas (e.g., natural gas and the like), into an electric furnace vessel. The lance assembly includes a housing portion, a straight barrel having a first and connected to the housing portion and a second end connected to a lance tip. The lance tip includes a nozzle structure having at least one oxygen injection nozzle and at least one carbonaceous material injection nozzle which together define a burner assembly for dispensing a combined flow of carbonaceous fuel and oxygen from the lance which may be ignited to produce a flame for preheating a scrap charge in an electric furnace vessel. When the scrap is sufficiently melted through cooperation of the electric furnace electrodes and the burner, the oxygen and carbonaceous fuel material flows may be terminated to extinguish the burner flame, the oxygen flow may be restarted at a reduced flow rate to complete preheating/cutting (if necessary), or at a supersonic flow rate for refining/decarburizing of the molten steel bath.