Abstract: An inshot burner (10) includes an axially elongated tubular nozzle (40) having a flared inlet end (42), a cylindrical outlet end (44) and a venturi section (46) therebetween. A burner head insert (20) is disposed within the cylindrical outlet end 44. The burner head insert (20) has an axially elongated annular body (22) having an axially extending inner flow passage (25) passing therethrough and a plurality of circumferentially spaced, axially extending splines (30) radiating outwardly therefrom toward the surrounding wall of the outlet end (44) of the burner tube. A plurality of second flow passages (35) are defined between the plurality of splines (30). Each of the axially extending splines (30) has a cross width which enlarges in the axial direction from the inlet end of the burner head insert to the outlet end of the burner head insert.

Abstract: The fuel in the fuel rich inner cone of the flame is catalyzed by a partial oxidation catalyst into carbon monoxide and hydrogen which have a lower peak flame temperature thereby reducing thermal NO.sub.x. The insert is heated and radiates heat with a further reduction of peak flame temperature.

Abstract: A mixing/quenching device is in the form of a stack of perforate metal sheets secured together with the perforations aligned to define continuous flow paths. The interfaces of the laminations in the flow path provides turbulence and the thermal mass of the device provides heat transfer such that thermal NO.sub.x is reduced.