Abstract: The present disclosure relates to a fuel-air premixer for a turbine system. The fuel-air premixer includes a swirler and a centerbody. The swirler is configured to direct a flow of air through the premixer, and the centerbody is configured to inject fuel into the flow of air. Additionally, the centerbody includes an airfoil shape that reduces and/or substantially eliminates recirculation pockets to prevent autoignition and/or flame holding in a combustion chamber. Accordingly, the turbine system may produce fewer NOx emissions.

Abstract: A fuel nozzle system for enabling a gas turbine to start and operate on low-Btu fuel includes a primary tip having primary fuel orifices and a primary fuel passage in fluid communication with the primary fuel orifices, and a fuel circuit capable of controlling flow rates of a first and second low-Btu fuel gases flowing into the fuel nozzle. The system is capable of operating at an ignition status, in which at least the first low-Btu fuel gas is fed to the primary fuel orifices and ignited to start the gas turbine, and a baseload status, in which at least the second low-Btu fuel gas is fired at baseload. The low-Btu fuel gas ignited at the ignition status has a content of the first low-Btu fuel gas higher than that of the low-Btu fuel gas fired at the baseload status. Methods for using the system are also provided.

Abstract: The present disclosure relates to a fuel-air premixer for a turbine system. The fuel-air premixer includes a swirler and a centerbody. The swirler is configured to direct a flow of air through the premixer, and the centerbody is configured to inject fuel into the flow of air. Additionally, the centerbody includes an airfoil shape that reduces and/or substantially eliminates recirculation pockets to prevent autoignition and/or flame holding in a combustion chamber. Accordingly, the turbine system may produce fewer NOx emissions.

Abstract: A system for premixing fuel and air prior to combustion in a gas turbine engine includes a mixing duct, a centerbody fuel injector located along a central axis of the mixing duct an outer annular swirler located adjacent an upstream end of the mixing duct for swirling air flowing therethrough in a first swirl direction and an inner annular swirler located adjacent of the mixing duct upstream end for swirling air flowing therethrough in a second swirl direction. The system includes a hub separating the inner and outer annular swirlers to permit independent rotation of an air stream therethrough and multiple hollow paths located radially outward around the centerbody fuel injector and at a radially inward side of the inner annular swirler for allowing a flow of sweeping air over the surface of the centerbody fuel injector.

Abstract: A system for premixing fuel and air prior to combustion in a gas turbine engine includes a mixing duct, a centerbody fuel injector located along a central axis of the mixing duct, an outer annular swirler located adjacent an upstream end of the mixing duct for swirling air flowing therethrough in a first swirl direction and an inner annular swirler located adjacent of the mixing duct upstream end for swirling air flowing therethrough in a second swirl direction. The system includes a hub separating said inner and outer annular swirlers to permit independent rotation of an air stream therethrough and multiple hollow paths located radially outward around the centerbody fuel injector and at a radially inward side of the inner annular swirler for allowing a flow of sweeping air over the surface of the centerbody fuel injector.

Abstract: A fuel nozzle system for enabling a gas turbine to start and operate on low-Btu fuel includes a primary tip having primary fuel orifices and a primary fuel passage in fluid communication with the primary fuel orifices, and a fuel circuit capable of controlling flow rates of a first and second low-Btu fuel gases flowing into the fuel nozzle. The system is capable of operating at an ignition status, in which at least the first low-Btu fuel gas is fed to the primary fuel orifices and ignited to start the gas turbine, and a baseload status, in which at least the second low-Btu fuel gas is fired at baseload. The low-Btu fuel gas ignited at the ignition status has a content of the first low-Btu fuel gas higher than that of the low-Btu fuel gas fired at the baseload status. Methods for using the system are also provided.