Abstract: A system of this invention reduces the emission of NO.sub.x and fuel pollutants from a furnace. The system includes a furnace with a chamber for combusting air, oxygen and fuel flows in an approximately stoichiometric proportion. A reburn unit, that can be a port, is coupled to communicate with and receive the combustion exhaust from the chamber. The reburn unit is also coupled to receive a second fuel flow that is added to the exhaust flow at a stoichiometric ratio and temperature at which a reaction occurs to lower the amount of NO.sub.x in the exhaust flow. The reburn unit is coupled to a burnout unit that can be a regenerator or a recuperator, that is coupled to receive an oxidant flow with air and/or oxygen. The oxidant flow combusts fuel in the exhaust flow to prevent emission of this fuel into the atmosphere.

Abstract: In a method of this invention, a first oxidant flow including oxygen and/or air, is injected into an exhaust gas flow from a primary burn zone in a furnace combustion chamber. The first oxidant flow is injected into the exhaust gas flow in a secondary burn zone downstream from the primary burn zone, but inside of the furnace chamber so that heat released from combustion of the first oxidant flow can be used for the purpose to which the furnace is applied. Also, the injection of the first oxidant flow into the secondary burn zone combusts fuel pollutants that might otherwise be released from the furnace into the atmosphere. The method can also include mixing a gaseous hydrocarbon fuel flow with the exhaust gas flow from the secondary burn zone to reduce the NO.sub.x, level in the exhaust gas. Also, the method can include mixing a second oxidant flow including air and/or oxygen, with the exhaust gas, preferably after reducing the NO.sub.x.