Power plants – Combustion products used as motive fluid
Reexamination Certificate
1999-01-08
2001-11-06
Casaregola, Louis J. (Department: 3746)
Power plants
Combustion products used as motive fluid
C060S039550, C060S740000
Reexamination Certificate
active
06311471
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to industrial power turbines, and, more specifically, to low NOx combustors therein.
Industrial gas turbine engines may be used alone for producing power by rotating an electrical generator, for example, or may be used in a combined cycle with a steam turbine. Industrial gas turbines are continually being developed for increasing thermal efficiency, increasing specific work, reducing exhaust emissions, and reducing overhead and running costs associated therewith.
Higher thermal efficiency may be effected by increasing the firing temperature of the combustor. However, the higher combustion gas temperature increases the difficulty of reducing NOx (nitrogen oxide) emissions therefrom. NOx is one of several undesirable exhaust emissions, also including unburned hydrocarbons and carbon monoxide, which are reduced by various means.
Axially staged combustion is one method for reducing undesirable exhaust emissions while increasing the firing temperature. NOx emissions can be reduced by this method when compared to a single stage combustor. Axial staging is effected by providing fuel injection at several axial locations in a combustor correspondingly configured for this purpose. Primary fuel and air is injected at the upstream or dome end of the combustor in a first stage. As required, for meeting high power operation, additional or secondary fuel and air are injected at an axially downstream location to provide axially staged combustion.
An axially staged combustor provides low NOx operation in a dry configuration without the complexity of steam injection used in past generation industrial power turbines. However, the second stage, or secondary, fuel injectors required in axial staged combustion are necessarily located downstream in the combustor and are subject to heating by the combustion gases first generated by burning of the fuel and air mixture from the primary fuel injectors.
The secondary fuel injectors may be cooled using the fuel flow through these injectors or a portion of compressor bleed air for the injectors, but these techniques are of limited efficacy. During low power operation, the secondary fuel injectors may not be called upon to provide substantial fuel flow, so that insufficient fuel is available for cooling the secondary fuel injectors. Moreover, bleeding of compressor air for cooling the secondary injectors correspondingly decreases the overall efficiency of the engine.
Accordingly, it would be desirable to provide improved cooling of a secondary fuel injector in a dry, low NOx, axially staged combustor.
BRIEF SUMMARY OF THE INVENTION
A fuel injector is cooled by steam during operation of a combustor. The injector includes a conduit for channeling fuel into the combustor, and a jacket covering the conduit through which the steam is channeled for cooling the injector.
REFERENCES:
patent: 4041699 (1977-08-01), Schelp
patent: 4893468 (1990-01-01), Hines
patent: 4982564 (1991-01-01), Hines
patent: 5054279 (1991-10-01), Hines
Campbell Robert Patrick
Correa Sanjay Marc
Dean Anthony John
Waldherr Gregor Arthur
Cabou Christian G.
Casaregola Louis J.
General Electric Company
Patnode Patrick K.
LandOfFree
Steam cooled fuel injector for gas turbine does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Steam cooled fuel injector for gas turbine, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Steam cooled fuel injector for gas turbine will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2575293