Late Lean Injection With Adjustable Air Splits

CATEGORY: TURBINES
PATENT
Late Lean Injection With Adjustable Air Splits
United States Patent Application 20120110974
Inventors:
Davis Jr., Lewis Berkley (Niskayuna, NY, US)
Venkataraman, Krishna Kumar (Simpsonville, SC, US)
Ziminsky, Willy Steve (Simpsonville, SC, US)
Myers, Geoffrey David (Simpsonville, SC, US)
Application Number: 13/345362
Publication Date: 05/10/2012
Assignee: GENERAL ELECTRIC COMPANY (Schenectady, NY, US)
Abstract:
A gas turbine engine is provided and includes a combustor having a first interior in which a first fuel is combustible, a turbine into which products of at least the combustion of the first fuel are receivable, a transition zone, including a second interior in which a second fuel and the products of the combustion of the first fuel are combustible, a plurality of fuel injectors which are configured to supply the second fuel to the second interior in any one of a single axial stage, multiple axial stages, a single axial circumferential stage and multiple axial circumferential stages, a compressor, by which air is supplied to the first and second interiors for the combustion therein, and a control system configured to control relative amounts of the air to the first and second interiors and relative amounts of the first and second fuels supplied to the first and second interiors.
BACKGROUND OF THE INVENTION
Aspects of the present invention are directed to late lean injection (LLI) fuel staging configurations and methods of achieving the same.
Currently, some gas turbine engines fail to operate at high efficiencies and produce undesirable air polluting emissions. The primary air polluting emissions usually produced by turbines burning conventional hydrocarbon fuels are oxides of nitrogen, carbon monoxide and unburned hydrocarbons. To this end, since oxidation of, e.g., molecular nitrogen, in gas turbine engines is dependent upon a high temperature in the combustor and the residence time for the reactants at the high temperature within the combustor, a level of thermal NOx formation is reduced by maintaining the combustor temperature below the level at which thermal NOx is formed or by limiting the residence time for the reactants at the high temperatures such that there is insufficient time for the NOx formation reactions to progress.
One temperature controlling method involves the premixing of fuel and air to form a lean mixture thereof prior to combustion. However, it has been seen that, for heavy duty industrial gas turbines, even with the use of premixed lean fuels, the required temperatures of the combustion products are so high that the combustor must be operated with peak gas temperatures in the reaction zone that exceed the thermal NOx formation threshold temperature, resulting in significant NOx formation.
BRIEF DESCRIPTION OF THE INVENTION
According to one aspect of the invention, a gas turbine engine is provided and includes a combustor having a first interior in which a first fuel supplied thereto by a fuel circuit is combustible, a turbine, including rotating turbine blades, into which products of at least the combustion of the first fuel are receivable to power the rotation of the turbine blades, a transition zone, including a second interior in which a second fuel supplied thereto by the fuel circuit and the products of the combustion of the first fuel are combustible, the transition zone being disposed to fluidly couple the combustor and the turbine to one another, a plurality of fuel injectors, which are structurally supported by the transition zone and coupled to the fuel circuit, and which are configured to supply the second fuel to the second interior in any one of a single axial stage, multiple axial stages, a single axial circumferential stage and multiple axial circumferential stages, a compressor, fluidly coupled to the combustor and the transition zone, by which air is supplied to the first and second interiors for the combustion therein, and a control system coupled to the fuel circuit and configured to control relative amounts of the air to the first and second interiors and relative amounts of the first and second fuels supplied by the fuel circuit to the first and second interiors.
According to another aspect of the invention, a gas turbine engine including a combustor having a first interior in which a first fuel supplied thereto by a fuel circuit is combustible and a turbine, including rotating turbine blades, into which products of at least the combustion of the first fuel are receivable to power the rotation of the turbine blades is provided and includes a transition zone, including a second interior in which a second fuel supplied thereto by the fuel circuit and the products of the combustion of the first fuel are combustible, the transition zone being disposed to fluidly couple the combustor and the turbine to one another, a plurality of fuel injectors, which are structurally supported by the transition zone and coupled to the fuel circuit, and which are configured to supply the second fuel to the second interior in any one of a single axial stage, multiple axial stages, a single axial circumferential stage and multiple axial circumferential stages, a compressor, fluidly coupled to the combustor and the transition zone, by which air is supplied to the first and second interiors for the combustion therein, and a control system coupled to the fuel circuit and configured to control relative amounts of the air to the first and second interiors and relative amounts of the first and second fuels supplied by the fuel circuit to the first and second interiors.
According to yet another aspect of the invention, a method of operating a gas turbine engine in which a turbine is fluidly coupled to a combustor by a transition zone interposed therebetween and in which a compressor supplies air to the combustor and the transition zone is provided and includes supplying a first fuel to a first interior within the combustor, combusting the first fuel in the first interior within the combustor, supplying a second fuel to a second interior within the transition zone in any one of a single axial stage, multiple axial stages, a single axial circumferential stage and multiple axial circumferential stages, combusting the second fuel and a stream of combustion products, received from the first interior, in the second interior within the transition zone, and controlling relative amounts of the air and the first and second fuels supplied to the first and second interiors.
These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.
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