| 摘要 |
System for reducing NOx emissions from burners of furnaces such as those used in steam cracking. The system includes a furnace having at least one burner, the at least one burner including a primary air chamber; a burner tube including a downstream end, an upstream end in fluid communication with the primary air chamber for receiving air, flue gas or mixtures thereof and fuel, a venturi portion positioned between the downstream end and the upstream end, and a burner tip mounted on the downstream end of the burner tube adjacent the first opening in the furnace for combusting the fuel downstream of the burner tip; and a fuel orifice located adjacent the upstream end of the burner tube for introducing fuel into the burner tube; a source of flue gas, said source positioned so as to enable the flue gas to achieve a temperature of less than 2000° F. at least one passageway for conducting flue gas from the source to the primary air chamber; and inspirating means, the inspirating means including the venturi portion effective for drawing flue gas from the source, through the at least one passageway and the primary air chamber in response to an inspirating effect of uncombusted fuel exiting the fuel orifice, the uncombusted fuel flowing through the burner tube from its upstream end towards its downstream end, whereby the flue gas is mixed with air at the upstream end of the burner tube prior to the zone of combustion of the fuel. |
