Burner with flue gas recirculation

Abstract

A burner for use in furnaces such as the type employed in steam cracking. The burner includes a primary air chamber, a burner tube including (i) a downstream end, (ii) an upstream end in fluid communication with the primary air chamber for receiving air, flue gas or mixtures thereof and fuel, and (iii) a burner tip mounted on the downstream end of the burner tube and directed to a first opening in the furnace, so that combustion of a combustible mixture including fuel and air takes place downstream of the burner tip, at least one flue gas recirculation duct having a first end at a second opening in the furnace and a second end opening into the primary air chamber, the at least one flue gas recirculation duct having at least one primary air channel in fluid communication with the at least one flue gas recirculation duct, and means for drawing flue gas from the furnace and primary air from a source of air, through the duct and into the primary air chamber, in response to an inspirating effect of uncombusted fuel flowing through the burner tube from its upstream end towards its downstream end. Optionally the flue gas recirculation duct has a plate member extending into the primary air chamber to create flow eddies to enhance further mixing of flue gas and air.