Methods and systems to facilitate operating within flame-holding margin

Abstract

A method to facilitate controlling flame-holding margins in a turbine engine is provided. The method includes coupling at least one turbine nozzle segment within the turbine engine, wherein the at least one turbine nozzle segment includes at least one vane extending between an inner band and an outer band. The method also includes positioning at least one fuel injection orifice in a surface of the at least one vane, channeling a fuel through the at least one fuel injection orifice into a compressed fluid flow to establish a jet penetration height, and defining an operating window by adjusting an operating parameter of the fuel to reduce the jet penetration height and to facilitate reducing the flame-holding margins.

Description

BACKGROUND OF THE INVENTION[0001]This invention relates generally to turbine assemblies, and more particularly, to methods and systems to facilitate controlling flame-holding margins during turbine operation.[0002]Generally, turbine assemblies used in power generation systems are designed for use with a particular fuel. More specifically, known turbines are designed to achieve mandated nitrous oxide (NOx) emission levels when operating. However, as the cost of gaseous fuels has increased, while gas fuel supplies have become more difficult to secure, at least some known turbines have had to operate with alternative fuels.[0003]At least some known methods of operating turbine assemblies economize fuel consumption by increasing the temperature of the fuel supplied to the turbines using waste heat. By increasing the temperature of the fuel supplied to the turbine, less energy is required to bring the fuel to a turbine operating temperature. For example, in a turbine having an operating ...

AI Technical Summary

Benefits of technology

[0005]In one embodiment, a method to facilitate operating within flame-holding margins in a turbine engine is provided. The method includes coupling at least one turbine nozzle segment within the turbine engine, wherein the at least one turbine nozzle segment includes at least one vane extending between an inner band and an outer band. The method also includes positioning at least one fuel injection orifice in a surface of the at least one vane, channeling a fuel through the at least one fuel injection orifice into a compressed fluid flow to establish a jet penetration height, and defining an operating window by adjusting an operating parameter of the fuel to reduce the jet penetration height and to facilitate increasing the flame-holding margins.

[0006]In another exemplary embodiment, a system to facilitate operating within flame-holding margins in a turbine engine is provided. The system includes at least one turbine nozzle segment coupled within the turbine engine, where the at least one turbine nozzle segment includes at least one vane extending between an inner band and an outer band. The system also includes a design fuel from a fuel source, at least one fuel injection orifice defined in a surface of the at least one vane, where the at least one fuel injection orifice is designed to optimize turbine performance using the design fuel. A non-design fuel is channeled through the at least one fuel injection orifice into a compressed fluid flow to establish a jet penetration height, and an operating window facilitates reducing the jet penetration height and facilitates increasing the flame-holding margins.

Problems solved by technology

However, as the cost of gaseous fuels has increased, while gas fuel supplies have become more difficult to secure, at least some known turbines have had to operate with alternative fuels.

Using these methods with non-design gas fuels may decrease the fuel nozzle's flame-holding margins below the desired allowable limits.

Flame holding may damage the fuel nozzle, creating hot streaks that exceed the local maximum operating temperature of turbine engines, thus causing turbines to fail.

Moreover, exceeding flame-holding margins may also limit the useful life of the fuel nozzles and / or may cause damage to the combustor lining.

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