Burner and combustion furnace

Abstract

A burner includes: a first nozzle shaped as a tube having a burner axis as a central axis, the first nozzle including a main fuel outlet from which the first nozzle ejects a fluid mixture of a main fuel and primary air; a flame-holding plate shaped as a truncated circular cone with a diameter that increases downstream, the flame-holding plate being located at a tip of the first nozzle and around a periphery of the main fuel outlet to generate a flame-holding eddy downstream of the flame-holding plate; a second nozzle including a secondary air outlet that surrounds the main fuel outlet and from which the second nozzle ejects secondary air; and an auxiliary fuel nozzle located in a second flow path that is defined between the first nozzle and the second nozzle and through which the secondary air flows, the auxiliary fuel nozzle including an auxiliary fuel outlet from which the auxiliary fuel nozzle ejects a gaseous fuel containing a nitrogen component along an outer surface of the flame-holding plate or an outer surface of the first nozzle. The flame-holding plate includes a protrusion located downstream of the auxiliary fuel outlet, the protrusion being circumferentially continuous on the outer surface of the flame-holding plate.

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