Can Combustor with Annular Burners for Gas Turbine Stability
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Solution Overview
Problem
Conventional can-annular combustors in gas turbines face challenges in operability, serviceability, and environmental performance, particularly in reducing NOx and CO emissions, and require cost-effective designs that enhance flame stability and operational robustness.
Innovation Solution
A can combustor design featuring a cylindrical casing with up to four premixed burners arranged in an annular pattern, each equipped with a conical swirl generator and mixing tube, utilizing co- and counter-swirl arrangements, multi-stage fuel supply, and varying burner geometries to reduce thermoacoustic instabilities and emissions, eliminating the central burner for cost savings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional can-combustor design with a central burner and more than five annular burners is used, then the combustor provides stable combustion, but the number of burners increases cost and complexity
Solution Approach 1:
The patent removes the central burner from the conventional combustor design, extracting only the necessary annular burners (maximally four) to achieve stable combustion. This reduction in burner count directly addresses the contradiction by lowering device complexity while maintaining combustion stability through optimized annular burner arrangement and multi-stage fuel supply.
Solution Approach 2:
Instead of having a central burner surrounded by annular burners, the patent inverts the arrangement by using only annular burners without a central element. This inversion simplifies the overall structure and reduces the number of components while still achieving the desired combustion performance through the annular configuration.
2Object-generated harmful factors
If premixed burners with conical swirl generators and multiple air inlet slots are used, then NOx emissions are reduced, but burner design complexity increases
Solution Approach 1:
The patent employs premixed burners with conical swirl generators featuring multiple air inlet slots, which fundamentally changes the mixing parameters of fuel and air. This parameter change enables complete premixing before combustion, significantly reducing NOx emissions. The standardized conical swirl generator design with varying slot configurations balances the reduction in harmful emissions with controlled design complexity.
3Reliability
If burners are arranged with different swirl directions (co-swirl and counter-swirl), then flame stability and operational robustness are enhanced, but the complexity of swirl generator configuration increases
Solution Approach 1:
The patent introduces asymmetry in the swirl generator configuration by implementing both co-swirl and counter-swirl directions among the annular burners. This asymmetric arrangement enhances flame stability and operational robustness by creating more complex flow patterns that resist instability. The selective application of different swirl directions optimizes combustion performance while managing configuration complexity through purposeful asymmetry.
4Ease of manufacture
If the number of burners is limited to maximally four per can, then cost savings are achieved, but the challenge of maintaining combustion stability increases
Solution Approach 1:
The patent merges the combustion function into maximally four annular burners, combining multiple functions into fewer components. By eliminating the central burner and optimizing the annular burners with multi-stage fuel supply and conical swirl generators, the design achieves cost savings while maintaining combustion stability through the consolidated burner arrangement.
Solution Approach 2:
The patent changes key combustion parameters through premixed burners with conical swirl generators and multi-stage fuel supply, enabling stable combustion with fewer burners. These parameter changes in fuel-air mixing and injection timing allow maximally four burners to achieve the combustion stability traditionally requiring more burners, thus reducing cost while maintaining reliability.
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 design achieves reduced emissions, improved flame stability, and a wider operating range with lower NOx and CO emissions, enhanced burner communication, and reduced sensitivity to combustion dynamics, leading to longer turbine part lifetimes and cost savings.
Implementation Method 1
each of said burners has a conical swirl generator and a mixing tube to induce a swirl flow of said fuel/air mixture
Implementation Method 2
conical swirl generator and a mixing tube to induce a swirl flow of said fuel/air mixture
Implementation Method 3
burners extending in an upstream direction from said front panel and having a burner exit, supported by this front panel, for supplying a fuel/air mixture into a combustion zone inside the can casing
Data Source
AI summary
The invention relates to a can-combustor for a can-annular combustor arrangement in a gas turbine. The can combustor includes an essentially cylindrical casing with an axially upstream front panel and an axially downstream outlet end. The can combustor further includes a number of premixed burners, extending in an upstream direction from said front panel and having a burner exit, supported by this front panel, for supplying a fuel/air mixture into a combustion zone inside the casing. Up to four premixed burners are attached to the front panel in a substantially annular array. Each burner has a conical swirl generator and a mixing tube to induce a swirl flow of said fuel/air mixture.