Panel Fuel Injectors for Axially Staged Combustion
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Solution Overview
Problem
Conventional gas turbine combustion systems face challenges in balancing air flow to various combustor components while maintaining emissions compliance over the full range of operation, particularly with axially staged fuel injection systems.
Innovation Solution
The segmented annular combustion system incorporates a series of fuel nozzles and panel fuel injectors arranged in an annular array, with axially staged fuel injection to enhance combustion efficiency and reduce emissions. This system includes bundled tube fuel nozzles and panel fuel injectors that are circumferentially spaced, allowing for precise control of fuel-air mixtures and improved combustion dynamics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If axially staged fuel injection is used to reduce emissions, then NOx and CO emissions are reduced, but air flow balancing becomes difficult to maintain over full operating range
Solution Approach 1:
The combustion system is divided into multiple axially staged zones with separate fuel injectors (primary fuel injectors at upstream location and secondary fuel injectors at downstream location), each controlling fuel-air mixing independently to reduce emissions while maintaining operational flexibility for air flow balancing across different operating conditions
Solution Approach 2:
The fuel injection system employs variable fuel flow rates to primary and secondary injectors that can be dynamically adjusted based on operating conditions, allowing the air-fuel ratio in each zone to be optimized in real-time for emissions reduction while maintaining proper air flow balance across the full operating range
2Object-generated harmful factors
If pre-mixing of fuel and air is implemented to control combustor temperature, then NOx production is reduced, but combustion efficiency may be compromised
Solution Approach 1:
Fuel and air are pre-mixed in controlled proportions in separate primary and secondary mixing zones before combustion, with the primary zone establishing a lean mixture to limit peak temperatures and NOx formation, while the secondary zone adds additional fuel that mixes with hot combustion gases to ensure complete combustion and maintain efficiency
Solution Approach 2:
Different fuel-air mixture qualities are created in different axial zones: the primary combustion zone uses a leaner pre-mixed fuel-air ratio to control temperature and reduce NOx, while the secondary combustion zone introduces additional fuel that mixes with the hot gases to optimize combustion efficiency in the high-temperature region
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The segmented annular combustion system effectively reduces NOx and CO emissions by optimizing fuel-air mixing and combustion temperatures, while maintaining efficient operation across a wide range of gas turbine conditions.
Implementation Method 1
pre-mixing fuel and air to create a fuel-air mixture prior to combustion
Implementation Method 2
Oxidization of molecular nitrogen in the gas turbine depends upon the temperature of gas located in a combustor, as well as the residence time for reactants located in the highest temperature regions within the combustor
Implementation Method 3
Industrial gas turbine combustion systems usually burn hydrocarbon fuels and produce air polluting emissions
Data Source
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AI summary
The present disclosure is directed to an annular combustion system. The annular combustion system includes an inner liner and an outer liner that define therebetween an annulus that circumscribes a centerline of the combustion system. The annulus includes a plurality of primary combustion zones defined at an upstream end thereof and further defines a plurality of secondary combustion zones downstream of the primary combustion zones. The annular combustion system further includes a plurality of fuel nozzles where at least one fuel nozzle discharges a combustible mixture into a respective primary combustion zone of the plurality of primary combustion zones. A plurality of panel fuel injectors is disposed between adjacent fuel nozzles. The plurality of panel fuel injectors extends in an axially downstream direction so as to separate adjacent primary combustion zones. Each panel fuel injector discharges a combustible mixture into at least one secondary combustion zone.