The present invention relates to combustion turbine engines, and more particularly, to integrating late lean injection into the combustion liner of combustion turbine engines, late lean injection sleeve assemblies, and/or methods of manufacture related thereto.
Multiple designs exist for staged combustion in combustion turbine engines, but most are complicated assemblies consisting of a plurality of tubing and interfaces. One kind of staged combustion used in combustion turbine engines is late lean injection. In this type of stage combustion, late lean fuel injectors are located downstream of the primary fuel injector. As one of ordinary skill in the art will appreciate, combusting a fuel/air mixture at this downstream location may be used to improve NOx performance. NOx, or oxides of nitrogen, is one of the primary undesirable air polluting emissions produced by combustion turbine engines that burn conventional hydrocarbon fuels. The late lean injection may also be function as an air bypass, which may be used to improve carbon monoxide or CO emissions during “turn down” or low load operation. It will be appreciated that late lean injection systems may provide other operational benefits.
Current late lean injection assemblies are expensive and costly for both new gas turbine units and retrofits of existing units. One of the reasons for this is the complexity of conventional late lean injection systems, particularly those systems associated with the fuel delivery. The many parts associated with these complex systems must be designed to withstand the extreme thermal and mechanical loads of the turbine environment, which significantly increases manufacturing expense. Even so, conventional late lean injection assemblies still have a high risk for fuel leakage into the compressor discharge casing, which can result in auto-ignition and be a safety hazard. In addition, the complexity of conventional systems increases the cost to assembly.
As a result, there is a need form improved late lean injection systems, components, and methods of manufacture, particularly those that reduce system complexity, assembly time, and manufacturing cost.