A method and apparatus for use in burners of furnaces such as those used in
steam cracking. The apparatus includes a burner tube having a burner tip
mounted on the downstream end of the burner tube adjacent to a first
opening in the furnace, so that combustion of the fuel takes place
downstream of the burner tip. At least one passageway from a second
opening in the furnace ending adjacent to the upstream end of the burner
tube is provided. Also provided is a means for drawing flue gas from the
furnace through the passageway in response to an inspirating effect
created by uncombusted fuel flowing through the burner tube. At least one
heat exchange tube disposed in the passageway wherein air that is cooler
than the flue gas flows through the heat exchange tube into a secondary
air chamber permitting heat to be transferred from the flue gas to the air
to create preheated air.
