Abstract: Lean premixed combustion of a hydrocarbon fuel and air is combined with lean direct injection of hydrocarbon fuel and carrier fluid such as air or inert gas or a mixture of air and inert gas into a combustor downstream of the premixed reaction zone in order to achieve extremely low levels of emissions of oxides of nitrogen at the high combustor exit temperatures required by advanced heavy duty industrial gas turbines. One or more premixing fuel nozzles are used to supply a lean mixture of hydrocarbon fuel and air to the main or primary reaction zone of a gas turbine combustor. This lean fuel/air mixture has an adiabatic flame temperature below the temperature that would result in substantial thermal NOx formation. After this low temperature reaction has been completed.

Abstract: Lean premixed combustion of a hydrocarbon fuel and air is combined with lean direct injection of hydrocarbon fuel and carrier fluid such as air or inert gas or a mixture of air and inert gas into a combustor downstream of the premixed reaction zone in order to achieve extremely low levels of emissions of oxides of nitrogen at the high combustor exit temperatures required by advanced heavy duty industrial gas turbines. One or more premixing fuel nozzles are used to supply a lean mixture of hydrocarbon fuel and air to the main or primary reaction zone of a gas turbine combustor. This lean fuel/air mixture has an adiabatic flame temperature below the temperature that would result in substantial thermal NOx formation.

Abstract: Lean premixed combustion of a hydrocarbon fuel and air is combined with lean direct injection of hydrocarbon fuel and air into a combustor downstream of the premixed reaction zone in order to achieve extremely low levels of emissions of oxides of nitrogen at the high combustor exit temperatures required by advanced heavy duty industrial gas turbines. One or more premixing fuel nozzles are used to supply a lean mixture of hydrocarbon fuel and air to the main or primary reaction zone of a gas turbine combustor. This lean fuel/air mixture has an adiabatic flame temperature below the temperature that would result in substantial thermal NOx formation. After this low temperature reaction has been completed, additional fuel and air are injected into the products of combustion downstream of the main reaction zone in order to raise the temperature of the mixture to the level required to operate an advanced, high efficiency, heavy duty industrial gas turbine at high load.

Abstract: A combustor for a gas turbine includes a diffusion flame combustion zone, a catalytic combustion zone and a post-catalytic combustion zone. At start-up or low-load levels, fuel and compressor discharge air are supplied to the diffusion flame combustion zone to provide combustion products for the turbine. At mid-range operating conditions, the products of combustion from the diffusion flame combustion zone are mixed with additional hydrocarbon fuel for combustion in the presence of a catalyst in the catalytic combustion zone. Because the fuel/air mixture in the catalytic reactor bed is lean, the combustion reaction temperature is too low to produce thermal NO.sub.x. Under high-load conditions, a lean direct injection of fuel/air is provided in a post-catalytic combustion zone where auto ignition occurs with the reactions going to completion in the transition between the combustor and turbine section.

Abstract: A combustor for a gas turbine includes a diffusion flame combustion zone, a catalytic combustion zone and a post-catalytic combustion zone. At start-up or low-load levels, fuel and compressor discharge air are supplied to the diffusion flame combustion zone to provide combustion products for the turbine. At mid-range operating conditions, the products of combustion from the diffusion flame combustion zone are mixed with additional hydrocarbon fuel for combustion in the presence of a catalyst in the catalytic combustion zone. Because the fuel/air mixture in the catalytic reactor bed is lean, the combustion reaction temperature is too low to produce thermal NO.sub.x. Under high-load conditions, a lean direct injection of fuel/air is provided in a post-catalytic combustion zone where auto ignition occurs with the reactions going to completion in the transition between the combustor and turbine section.

Abstract: A fuel trimming unit has been adapted to each combustion chamber in a multi-chamber combustor of an industrial gas turbine. The fuel trim unit matches the combustion air flow into each combustion chamber. This adjusts the fuel-air mixture to account for air flow variations into the individual combustion reaction zones of each combustion chamber. Because of the fuel trim unit, a uniform fuel-air mixture is provided to each combustion chamber in a gas turbine. The fuel trim unit is adjusted using sensor inputs of the fuel flow rate to each combustion chamber, the dynamic pressure in each combustion chamber, and the turbine exhaust temperature.

Abstract: A fuel trimming unit has been adapted to each combustion chamber in a multi-chamber combustor of an industrial gas turbine. The fuel trim unit matches the combustion air flow into each combustion chamber. This adjusts the fuel-air mixture to account for air flow variations into the individual combustion reaction zones of each combustion chamber. Because of the fuel trim unit, a uniform fuel-air mixture is provided to each combustion chamber in a gas turbine. The fuel trim unit is adjusted using sensor inputs of the fuel flow rate to each combustion chamber, the dynamic pressure in each combustion chamber, and the turbine exhaust temperature.

Abstract: A gas turbine combustion system includes a plurality of combustors within a pressure vessel, each combustor including a combustion liner defining a combustion chamber having a reaction zone and a dilution zone, the liner in the dilution zone provided with a plurality of circumferentially spaced dilution air feed holes. A flow shield surrounds each combustion liner in radially spaced relation thereto for feeding compressor discharge air to the combustion chamber. Air staging apparatus directly controls the amount of compressor discharge air fed into each combustion chamber dilution zone via the dilution air feed holes.

Abstract: A fuel trimming unit has been adapted to each combustion chamber in a multi-chamber combustor of an industrial gas turbine. The fuel trim unit matches the combustion air flow into each combustion chamber. This adjusts the fuel-air mixture to account for air flow variations into the individual combustion reaction zones of each combustion chamber. Because of the fuel trim unit, a uniform fuel-air mixture is provided to each combustion chamber in a gas turbine. The fuel trim unit is adjusted using sensor inputs of the fuel flow rate to each combustion chamber, the dynamic pressure in each combustion chamber, and the turbine exhaust temperature.

Abstract: Dual fuel/air injectors are provided, including a conventional central diffusion flame fuel nozzle 12. A fuel injector 14 for pre-mixing fuel and air for low emissions combustion and coaxial to the central nozzle includes a plenum 30 about the central injector having an air inlet 32, an annular pre-mix chamber 34, a fuel injection region 36 between the pre-mix chamber and air inlet 32 and an outlet 40 defined in part by swirler vanes 38. Radially projecting fuel spokes 46 extend into the plenum 30 and are supplied fuel from a manifold 44. Apertures 52 in the spokes supply fuel in a circumferential direction to the incoming air. The spokes in the plenum define throat areas T which, in the aggregate, define a minimum cross-sectional area of the plenum 30. Differential air flows through the throats provide inverse differential fuel distribution in the throats whereby a uniform fuel/air mixture strength distribution occurs at the throats.

Abstract: During low-load operating conditions, preburner combustion products are supplied with a chemical reactant to reduce NO.sub.x. The preburner products of combustion are mixed with a hydrocarbon fuel in the presence of a combustion catalyst to ignite and initiate a catalytic combustion reaction. The preburner is then shut down. The fuel/air mixture supplied the catalytic reactor bed during the mid-load operating range of the turbine is sufficiently lean to produce a combustion reaction temperature too low to produce thermal NO.sub.x. Thus, at low-load conditions, preburner combustion occurs with NO.sub.x reduction by chemical reactant, while the catalytic combustion occurs at mid-range operating conditions at temperatures too low to produce NO.sub.x. For high-load operating conditions, the catalytic combustion occurs as previously described and additional lean fuel/air mixture is supplied the reaction zone whereby thermal NO.sub.x is likewise avoided.

Abstract: A method and apparatus are provided for reducing NOx emissions in dual stage, dual mode gas turbine combustors. The gas turbine combustor includes first and second combustion chambers separated by a reduced diameter throat section. The throat section is formed by converging and diverging wall sections constructed of porous material. A liner is provided in surrounding relationship to the throat region to form a plenum by which predetermined amounts of air are metered into the plenum and permitted to pass through the porous throat wall sections.

Abstract: A laminated oxidation resistant catalyst element includes a metal alloy substrate such as a steel foil coated with a noble metal such as platinum. A ceramic washcoat such as alumina is applied over the noble metal and a catalyst is applied with the washcoat or individually during a subsequent application step. The noble metal prevents oxygen from contacting the metal substrate thereby preventing its degradation by oxidation reactions. The catalyst element is particularly suited for use in a catalytic reactor bed of an industrial gas turbine.

Abstract: A fuel gas injector for a gas turbine engine employs a plurality of closely spaced parallel venturi tubes disposed in a pair of spaced-apart header plates. The venturi tubes are brazed to the header plates and the perimeters of the header plates are sealed to form a plenum into which pressurized gaseous fuel is supplied. Orifices lead from the plenum to throats of the venturi tubes thereby injecting the gaseous fuel at right angles into the high-velocity air stream existing at the the throats of the venturi tubes. High shear is imposed on the injected fuel for providing complete mixing with the air. The high air velocity in the throats of the venturi tubes avoids flashback and flameholding. The combined flow from the plurality of venturi tubes mixes downstream thereof to provide a uniform velocity and fuel-air mixture across the flow field. This flow field is suitable for use in a catalyst bed which may be disposed downstream of the venturi tubes.

Abstract: A fuel gas injector for a gas turbine engine employs a plurality of closely spaced parallel venturi tubes disposed in a pair of spaced-apart header plates. The venturi tubes are brazed to the header plates and the perimeters of the header plates are sealed to form a plenum into which pressurized gaseous fuel is supplied. Orifices lead from the plenum to throats of the venturi tubes thereby injecting the gaseous fuel at right angles into the high-velocity air stream existing at the throats of the venturi tubes. High shear is imposed on the injected fuel for providing complete mixing with the air. The high air velocity in the throats of the venturi tubes avoids flashback and flameholding. The combined flow from the plurality of venturi tubes mixes downstream thereof to provide a uniform velocity and fuel-air mixture across the flow field. This flow field is suitable for use in a catalyst bed which may be disposed downstream of the venturi tubes.

Abstract: In a gas turbine power plant fuel and air are mixed and ignited in a combustor to provide motive fluid for driving a gas turbine. A fuel nozzle is used to provide a fuel/air mixture into the combustor. According to the present invention, the fuel nozzle also includes an igniter for igniting the fuel/air mixture under conditions which extend the operating range of the gas turbine plant. Also, the igniter is coated with a gas fuel ignition catalyst in order to minimize the fuel/air mixture strength required for combustion and the air pollutants associated with combustion.

Abstract: The trend toward improving air quality has caused manufacturers of gas turbines to implement direct catalytic reaction of carbon monoxide or hydrocarbons in the gas turbine combustion path. This requires mounting a catalytic reactor directly in the combustion path of the gas turbine which subjects the reactor to shock and thermal loadings, relative thermal displacements between different materials and leakage of combustion products around the catalytic reactor. A catalytic reactor is mounted within an outer structural lines, whereas a compliant and inflatable inner liner is included to support the reactor bed in the radial direction on a cushion of air derived from the compressor discharge air through an air inlet in the outer liner.