Westinghouse Electric Corporation

The United States of America As Represented by the United States

Paul W Pillsbury

Serafino M DeCorso

David T Foss

An ultra-low NOx gas turbine combustor having a dual fuel capability. The combustor has a plurality of venturis in flow communication with a corresponding number of fuel lances such that fuel injected from each lance into a corresponding venturi is mixed with high velocity air also flowing into the venturis. A vee-gutter flame holder is positioned downstream of the array of venturis for holding a combustion flame within the combustor at stable conditions. Due to the high velocities of the air-fuel mixture in the vicinity of the flame-holder, as a result of the fuel-air mixing in the venturis, destructive flash back conditions are obviated. A stable flame within the combustor provides for minimum acoustic disturbance and low overall pressure losses within the combustor provide for high operating efficiency levels of the turbine apparatus. Burning of the fuel in air at lean mixtures allows for minimal operation of a conventional pilot nozzle assembly so as to reduce the undesirable formation of NOx.

Multiple venturi ultra-low nox combustor

An ultra-low NOx gas turbine combustor having a dual fuel capability. The combustor has a pre-mixing zone and a downstream combustion zone. The pre-mixing zone has three concentric annular passages that surround a central diffusion-type dual fuel nozzle. A gas fuel manifold distributes gas fuel around the inner and outer passages. A plurality of dual fuel nozzles are disposed in the middle passage to distribute either gas or oil fuel around the middle passage. The distribution of fuel around the passages allows the formation of lean fuel/air ratios, thereby lowering NOx formation. In addition, swirl vanes are arrayed around the inner and outer passages and around each of the fuel nozzles. A step increase in the flow area in going from the pre-mixing zone to the combustion zone creates vortices that tend to anchor the flame.

Dual fuel ultra-low NOX combustor

A topping combustor is provided for a gas turbine power plant in which the combustion air from the compressor section of the gas turbine is heated in an indirect heat exchanger disposed in a solid fuel fired furnace. The compressed air from the compressor section flows through an annular passage enclosing the combustor inner shell on its way to the furnace, thereby cooling the inner shell. A burner comprised of a fuel distributor plate assembly having a plurality of fuel nozzles mounted therein is disposed in the inner vessel. Further compressed and cooled air from the compressor section flows through the plate assembly and mixes with a conventional fuel supplied to the fuel nozzles. A plurality of holes are formed in the plate assembly which distribute the combustion air around the nozzles. The high combustion air temperature and low gas velocity downstream of the plate assembly allow stable combustion to occur at ultra-lean fuel/air ratios, thereby minimizing the formation of NO.sub.x.

Topping combustor for an indirect fired gas turbine

Direct coal-fired gas turbine systems and methods for their operation are provided by this invention. The gas turbine system includes a primary zone for burning coal in the presence of compressed air to produce hot combustion gases and debris, such as molten slag. The turbine system further includes a secondary combustion zone for the lean combustion of the hot combustion gases. The operation of the system is improved by the addition of a cyclone separator for removing debris from the hot combustion gases. The cyclone separator is disposed between the primary and secondary combustion zones and is in pressurized communication with these zones. In a novel aspect of the invention, the cyclone separator includes an integrally disposed impact separator for at least separating a portion of the molten slag from the hot combustion gases.

Slag processing system for direct coal-fired gas turbines

Direct coal-fired gas turbine systems and methods for their operation are provided by this invention. The systems include a primary combustion compartment coupled to an impact separator for removing molten slag from hot combustion gases. Quenching means are provided for solidifying the molten slag removed by the impact separator, and processing means are provided forming a slurry from the solidified slag for facilitating removal of the solidified slag from the system. The released hot combustion gases, substantially free of molten slag, are then ducted to a lean combustion compartment and then to an expander section of a gas turbine.

Hydrocarbon fuel is combusted in a combustion turbine by a method which produces NO.sub.x emmissions below an ultra-low standard. In the method, first, a mix of hydrocarbon fuel and air in a primary flow thereof is burned in a primary combustion zone so as to produce a flow of hot gas of a temperature above that required for an efficient catalytic reaction and which contains NO.sub.x at levels below a low standard but above the ultra-low standard. Next, the hot gas is mixed with hydrocarbon fuel in a secondary flow thereof in a mixing and vaporization zone to provide a flow of heated fuel mixture of a temperature above that required for an efficient catalytic reaction. Thereafter, the heated fuel mixture is inefficiently catalytically reacted in a first catalytic element fuel to provide a flow of effluent gas of a temperature above that required for an efficient catalytic reaction and which contains NO.sub.x at levels below the ultra-low standard and CO and unburned hydrocarbons (UHC) at levels above an acceptable standard. Then, the CO and UHC in the effluent gas flow is mixed in a mixing completion zone to produce a flow of heated mixed effluent gas of a temperature above that required for an efficient catalytic reaction. Finally, the heated mixed effluent gas is efficiently catalytically oxidized in a second catalytic element to provide a flow of exhaust gas having emissions which contains NO.sub.x at levels below the ultra-low standard and CO and UHC at levels below the acceptable standard.

Method of reducing nox emissions from a stationary combustion turbine

Apparatus and method for starting a gas turbine engine is shown wherein the combustion chamber has a fixed geometry providing a high throughput velocity to prevent flashback during normal operation of the engine. Thus, there is provided a flame holding zone out of the main flow path through the chamber that exhausts into the chamber upstream of a catalytic reactor element to preheat the catalyst to a sufficiently high temperature for continuous auto-combustion therein prior to the rotor of the engine attaining running speed. After running speed the combustion in the flame holding zone is extinguished and the velocity of the fuel/air mixture in the main flow path through the chamber is sufficient to maintain the combustion within the catalytic element for the continuous running of the engine without any flashback.

Apparatus and method for starting a large gas turbine having a catalytic

A catalytic combustor arrangement for use with a gas turbine power plant, has independently regulatable fuel injection elements disposed upstream of a discrete array of passageways disposed between the fuel injection elements and a catalytic reaction member. The centermost fuel injection elements of each combustor may function alone which will permit efficient idling operation of the power plant. The passageways will maintain the flow of fuel and air to only the central portion of each catalytic reactor element thus providing the efficient, low speed, idling, operation of the turbine. As additional fuel injection elements are activated, additional portions of the catalytic reaction member perform the combustion function at the desired level of turbine operation. Thus a wide range of operating conditions of the gas turbine is efficiently permitted with the regulatable fuel injection arrangement therewith.

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Winter Springs, FL, United States of America

Paul W Pillsbury