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  Burner, gas turbine combustor, burner cooling method, and burner modifying methodUSPTO Application #: 20070003897Title: Burner, gas turbine combustor, burner cooling method, and burner modifying method Abstract: In a burner for injecting mixed gas fuel containing at least one of hydrogen and carbon monoxide into a combustion chamber of a gas turbine combustor, the burner includes a fuel nozzle for startup from which liquid fuel is injected into the combustion chamber, and a mixed fuel nozzle disposed around the fuel nozzle for injecting the mixed gas fuel. An air swirler is disposed at a downstream end of the mixed fuel nozzle and has a plurality of flow passages from which compressed air is injected into the combustion chamber, and the mixed fuel nozzle has injection ports disposed in the inner peripheral side of the flow passages of the air swirler. Cooling holes formed in the nozzle surface and positioned to face the combustion chamber introduce a part of the mixed gas fuel injected from the mixed fuel nozzle into the combustion chamber. (end of abstract) Agent: Mattingly, Stanger, Malur & Brundidge, P.C. - Alexandria, VA, US Inventors: Hiromi Koizumi, Hiroshi Inoue, Toshifumi Sasao, Isao Takehara USPTO Applicaton #: 20070003897 - Class: 431354000 (USPTO) Related Patent Categories: Combustion, Mixer And Flame Holder The Patent Description & Claims data below is from USPTO Patent Application 20070003897. Brief Patent Description - Full Patent Description - Patent Application Claims
BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a burner using mixed fuel containing at least one of hydrogen and carbon monoxide, and also relates to a gas turbine combustor, a burner cooling method, and a burner modifying method. [0003] 2. Description of the technology [0004] Recently, the varieties of fuel for use in gas turbines have been increased. The use of multi-component mixed gas fuel containing hydrogen, carbon monoxide, etc. (hereinafter referred to simply as "mixed fuel") has been proposed in addition to conventional primary fuel for gas turbines, such as LNG (liquefied natural gas), light oil, and A-heavy oil. Such mixed fuel has a higher flame temperature than LNG. In particular, hydrogen has a wider flammable range and a faster burning velocity and is easy to burn. [0005] LNG is burned primarily by employing a premixed combustion system. However, when the mixed fuel is burned by employing the premixed combustion system, flashback is apt to occur due to change of combustion characteristics caused by change of fuel composition and the presence of hydrogen and/or carbon oxide in the mixed fuel. It is therefore difficult to burn the mixed fuel by employing the premixed combustion system. For that reason, the mixed fuel is generally burned by a burner employing a diffusive combustion system in which fuel and air are separately injected into a combustion chamber (see, e.g., Patent Document 1: JP,A 2004-3730). SUMMARY OF THE INVENTION [0006] In the case of using the mixed fuel containing hydrogen, even when the mixed fuel is burned in a manner of diffusive combustion, due care has to be paid to safety at the time of ignition in a gas turbine. It is hence desired that another kind of fuel, e.g., light oil, be used at the startup of the gas turbine. When another kind of fuel, e.g., light oil, is used to start up the gas turbine, the operating mode is shifted from a mode using fuel for the startup to a gas combustion mode using only the mixed fuel after the steps of startup, acceleration and application of load. Herein, the term "gas combustion mode" means the operating mode in which only the mixed fuel is supplied to a combustor. However, after the shift to the gas combustion mode using only the mixed fuel, there is a fear that a flame may become apt to come close to a nozzle surface and metal temperature at the nozzle surface may rise excessively because the mixed fuel has a higher flame temperature and a faster burning velocity. [0007] An object of the present invention is to provide a burner, a gas turbine combustor, a burner cooling method, and a burner modifying method, which can hold metal temperature at a nozzle surface within a proper range and can increase reliability even when mixed fuel containing at least one of hydrogen and carbon monoxide is used as fuel. [0008] (1) To achieve the above object, the present invention provides a burner for injecting mixed fuel containing at least one of hydrogen and carbon monoxide into a combustion chamber of a gas turbine combustor, wherein the burner comprises a fuel nozzle for startup from which fuel for startup is injected into the combustion chamber; a mixed fuel nozzle disposed around the fuel nozzle for startup and injecting the mixed fuel; an air swirler disposed at a downstream end of the mixed fuel nozzle positioned in the combustion chamber and having a plurality of flow passages through which a part of compressed air from a compressor is injected into the combustion chamber to hold a flame, the mixed fuel nozzle having injection ports disposed in the inner peripheral side of the flow passages of the air swirler; and cooling holes formed in a nozzle surface positioned to face the combustion chamber and introducing a part of the mixed fuel injected from the mixed fuel nozzle into the combustion chamber, to thereby reduce flame temperature near the nozzle surface. [0009] (2) In above (1), preferably, the fuel nozzle for startup comprises a liquid fuel nozzle for injecting liquid fuel for the startup of the gas turbine, and an atomizing air nozzle disposed around the liquid fuel nozzle and injecting atomizing air to atomize the liquid fuel. [0010] (3) In above (1), preferably, the fuel nozzle for startup is disposed at a center of a combustion liner forming the combustion chamber in the radial direction. [0011] (4) In above (1), preferably, the burner further comprises an inert gas supply system for supplying inert gas to the fuel nozzle for startup, wherein the inert gas from the inert gas supply system is supplied to the fuel nozzle for startup such that the inert gas is injected to the vicinity of the nozzle surface from the fuel nozzle for startup during a gas combustion mode using only the mixed fuel. [0012] (5) In above (1), preferably, the mixed fuel is any of coke oven gas, blast furnace gas, LD gas, coal, and heavy oil gasification gas. [0013] (6) Also, to achieve the above object, the present invention provides a gas turbine combustor for burning mixed fuel containing at least one of hydrogen and carbon monoxide, wherein the combustor comprises an outer casing serving as a pressure vessel; a combustion liner disposed inside the outer casing and forming a combustion chamber therein; a burner for forming a flame in the combustion chamber within the combustion liner; and a transition piece for introducing, to a burner, the burned gas generated with the formation of the flame by the burner, the burner comprising a fuel nozzle for startup from which fuel for startup is injected into the combustion chamber; a mixed fuel nozzle disposed around the fuel nozzle for startup and injecting the mixed fuel; an air swirler disposed at a downstream end of the mixed fuel nozzle positioned in the combustion chamber and having a plurality of flow passages through which a part of compressed air from a compressor is injected into the combustion chamber to hold a flame, the mixed fuel nozzle having injection ports disposed in the inner peripheral side of the flow passages of the air swirler; and cooling holes formed in a nozzle surface positioned to face the combustion chamber and introducing a part of the mixed fuel injected from the mixed fuel nozzle into the combustion chamber, to thereby reduce flame temperature near the nozzle surface. [0014] (7) Further, to achieve the above object, the present invention provides a method of cooling a burner employing a diffusive combustion system and injecting mixed fuel containing at least one of hydrogen and carbon monoxide into a combustion chamber of a gas turbine combustor, wherein the method comprises the steps of forming cooling holes in a nozzle surface positioned to face the combustion chamber such that a part of the mixed fuel is injected through the cooling holes; and injecting the part of the mixed fuel into the combustion chamber through the cooling holes, to thereby reduce flame temperature near the nozzle surface and suppress a rise of metal temperature at the nozzle surface. [0015] (8) Still further, to achieve the above object, the present invention provides a burner for injecting mixed fuel containing at least one of hydrogen and carbon monoxide into a combustion chamber of a gas turbine combustor, wherein the burner comprises a fuel nozzle for startup which comprises a liquid fuel nozzle for injecting liquid fuel for the startup of the gas turbine, and an atomizing air nozzle disposed around the liquid fuel nozzle and injecting atomizing air to atomize the liquid fuel; a mixed fuel nozzle disposed around the fuel nozzle for startup and injecting the mixed fuel; an air swirler disposed at a downstream end of the mixed fuel nozzle positioned in the combustion chamber and injecting a part of compressed air from a compressor into the combustion chamber to hold a flame; and an inert gas supply system for supplying inert gas to the fuel nozzle for startup, the inert gas from the inert gas supply system being supplied to the fuel nozzle for startup such that the inert gas is injected to the vicinity of a nozzle surface from the fuel nozzle for startup during a gas combustion mode using only the mixed fuel. [0016] (9) Still further, to achieve the above object, the present invention provides a gas turbine combustor for burning mixed fuel containing at least one of hydrogen and carbon monoxide, wherein the combustor comprises an outer casing serving as a pressure vessel; a combustion liner disposed inside the outer casing and forming a combustion chamber therein; a burner for forming a flame in the combustion chamber within the combustion liner; and a transition piece for introducing, to a turbine, burned gas generated with the formation of the flame by the burner, the burner comprising a fuel nozzle for startup which comprises a liquid fuel nozzle for injecting liquid fuel for the startup of the gas turbine, and an atomizing air nozzle disposed around the liquid fuel nozzle and injecting atomizing air to atomize the liquid fuel; a mixed fuel nozzle disposed around the fuel nozzle for startup and injecting the mixed fuel; an air swirler disposed at a downstream end of the mixed fuel nozzle positioned in the combustion chamber and injecting a part of compressed air from a compressor into the combustion chamber to hold a flame; and an inert gas supply system for supplying inert gas to the fuel nozzle for startup, the inert gas from the inert gas supply system being supplied to the fuel nozzle for startup such that the inert gas is injected to the vicinity of a nozzle surface from the fuel nozzle for startup during a gas combustion mode using only the mixed fuel. [0017] (10) Still further, to achieve the above object, the present invention provides a method of cooling a burner employing a diffusive combustion system and injecting mixed fuel containing at least one of hydrogen and carbon monoxide into a combustion chamber of a gas turbine combustor, wherein the method comprises the steps of providing a mixed fuel nozzle for injecting the mixed fuel to be disposed around a fuel nozzle for startup from which fuel for startup is injected into the combustion chamber; and supplying inert gas from an inert gas supply system to the fuel nozzle for startup such that the inert gas is injected to the vicinity of a nozzle surface from the fuel nozzle for startup during a gas combustion mode using only the mixed fuel, thereby reducing flame temperature near the nozzle surface and suppressing a rise of metal temperature at the nozzle surface. [0018] (11) Still further, to achieve the above object, the present invention provides a burner for injecting mixed fuel containing at least one of hydrogen and carbon monoxide into a combustion chamber of a gas turbine combustor, wherein the burner comprises a fuel nozzle for startup from which fuel for startup is injected into the combustion chamber; a mixed fuel nozzle disposed around the fuel nozzle for startup and injecting the mixed fuel; an air swirler disposed at a downstream end of the mixed fuel nozzle positioned in the combustion chamber and having a plurality of flow passages through which a part of compressed air from a compressor is injected into the combustion chamber to hold a flame, the mixed fuel nozzle having injection ports disposed in the inner peripheral side of the flow passages of the air swirler; and a unit for purging the fuel residing in the fuel nozzle for startup. [0019] (12) In above (11), preferably, the unit for purging the fuel includes a system for supplying a part of the mixed fuel, which is supplied to the mixed fuel nozzle, to the fuel nozzle for startup. [0020] (13) Still further, to achieve the above object, the present invention provides a burner for injecting mixed fuel containing at least one of hydrogen and carbon monoxide into a combustion chamber of a gas turbine combustor, wherein the burner comprises a fuel nozzle for startup from which fuel for startup is injected into the combustion chamber; a mixed fuel nozzle disposed around the fuel nozzle for startup and injecting the mixed fuel; a swirler disposed to face the combustion chamber and including an air swirler disposed at a downstream end of the mixed fuel nozzle positioned in the combustion chamber and having a plurality of flow passages through which a part of compressed air from a compressor is injected into the combustion chamber to hold a flame, the mixed fuel nozzle having injection ports disposed in the inner peripheral side of the flow passages of the air swirler; and a unit for reducing flame temperature in the vicinity of the swirler disposed to face the combustion chamber to be lower than the melting point of a swirler material. [0021] (14) Still further, to achieve the above object, the present invention provides a method of modifying a burner for injecting mixed fuel containing at least one of hydrogen and carbon monoxide into a combustion chamber of a gas turbine combustor, the burner comprising a fuel nozzle for startup which comprises a liquid fuel nozzle for injecting liquid fuel for the startup of the gas turbine, and an atomizing air nozzle disposed around the liquid fuel nozzle and injecting atomizing air to atomize the liquid fuel; a mixed fuel nozzle disposed around the fuel nozzle for startup and injecting the mixed fuel; and a plurality of flow passages which are formed in a downstream end of the mixed fuel nozzle positioned in the combustion chamber and through which a part of compressed air from a compressor is injected into the combustion chamber to hold a flame, wherein the method includes the step of additionally providing, on the burner, a unit for supplying inert gas to the atomizing air nozzle. [0022] According to the present invention, even when the mixed fuel containing at least one of hydrogen and carbon monoxide is used as fuel, the flame temperature can be reduced by increasing a fuel concentration near the nozzle surface, whereby the metal temperature at the nozzle surface can be held within a proper range and reliability can be increased. In addition, the metal temperature at the nozzle surface can also be held within the proper range by supplying inert gas to the vicinity of the nozzle surface. Continue reading... Full patent description for Burner, gas turbine combustor, burner cooling method, and burner modifying method Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Burner, gas turbine combustor, burner cooling method, and burner modifying method patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. 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