GB798979A - Flare stack gas burner - Google Patents

Abstract

798,979. Gas burners. ZINK CO., J. Aug. 17, 1956, No. 25271/56. Classes 75(1) and 75(3) A flare stack burner for the combustion of waste gases comprises a vertically disposed tube 10 supplied at its lower end with the waste gases and having a burner tip 11 at its upper end, a plurality of pilot burners 23, 41, 43 circumferentially spaced about the burner tip 11 and a sleeve 61 surrounding an upper portion of the tube 10 and spaced therefrom to provide an annular passage 62 which is open to atmosphere at its lower end and through which air is induced to flow upwardly by the heat of the burner to cool the upper portion of the stack. The burner tip 11 comprises an annular member having a relatively large central opening 12 and two series of peripheral openings 21, 22 arranged so that the gas streams of each opening 21 impinges on the gas stream of a corresponding opening 22. A plurality of steam nozzles 48 extend vertically upwardly to positions above the burner tip 11 from a manifold 46 surrounding the upper end of the flame stack and then extend inwardly at angles to the vertical to discharge steam into the flame of the waste gas. The steam entrains air and the steam and air prevents the formation of free carbon in the flame. Steam is also discharged into the centre of the flame by orifices in a tip 54 on the end of a steam tube 53 arranged within a further tube 51 coaxially mounted in the burner tube 10 and terminating flush with the burner tip 11. The lower end of the tube 51 is open to atmosphere and the steam jets induce a flow of air up the annular space between the tubes 51, 53 to mix with the steam. Steam jets also issue from openings 66 in the manifold 46 and are directed upwardly through openings 64 in the sleeve 61 and induce flow of cooling air in the annular passage 62. The steam supply to the manifold 46 and to the central steam tube 53 is controlled by a valve 79, Fig. 1, operated by a mechanism 81 responsive to the waste gas pressure adjacent the inlet to a restricted orifice 76 in the burner tube 10 so that the steam pressure and hence the volume of cooling air in the annular passage 62 increases with increase in waste gas pressure. Each pilot burner comprises a tip 26, Fig. 7, having a large central gas discharge opening 27 and a conical wall having two rings of discharge ports 28, 29 providing intersecting gas jets. The tip is mounted on the upper end of a vertical tube 36, Fig. 1, connected at its lower end to a mixing tube 34 -of relatively small diameter supplied with gas and air. Two of the three pilot burners have the upper end of the vertical supply tube inclined so that the pilot flame is directed inwardly into the main flame. Each pilot burner is ignited by an electric filament igniter 37 mounted in the wall of the vertical supply pipe 36 at a position intermediate of its length. The filament is energized at all times but its temperature is normally below ignition temperature as a result of the cooling action of the continuous flow of gas-air mixture. If the gas supply fails the filament temperature consequently rises to a temperature sufficient to ignite the mixture when the gas supply is restored. The pilot burner may also be ignited by a flame travelling up a tube 39 supplied with a gas air mixture at its lower end and joined at its upper end to the vertical supply pipe tube 36 above the filament igniter 37. The .mixture in the tube 39 is ignited by firing a blank cartridge. Baffles close the upper end of the annular air and steam passage 62 below the heads of the pilot burners.