A burner for use in furnaces such as those employed in steam cracking. The burner includes a primary air chamber for supplying a first portion of air, a burner tube having an upstream end and a downstream end, a burner tip having an outer diameter, the burner tip mounted on the downstream end of the burner tube adjacent a first opening in the furnace, so that combustion of the fuel takes place downstream of the burner tip producing a gaseous fuel flame, at least one air port in fluid communication with a secondary air chamber for supplying a second portion of air, the at least one air port radially positioned beyond the outer diameter of the burner tip and at least one non-gaseous fuel gun for supplying atomized non-gaseous fuel, the at least one non-gaseous fuel gun having at least one fuel discharge orifice, the at least one non-gaseous fuel gun positioned within the at least one air port.