Gas Turbine Combustor Flame Flashback Control
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Solution Overview
Problem
Gas turbine combustors face challenges in promptly extinguishing flames within premixers without reducing output power, particularly due to increased burning velocity and flashback occurrences, which can lead to increased nitrogen oxides emissions and heat load on downstream structures.
Innovation Solution
A gas turbine combustor system incorporating a diffusion burner and a premixed burner with a control device that adjusts fuel flow rates using diffusion and premixed gas control valves, where a thermometer detects excessive temperatures to reduce the premixed fuel flow and increase diffusion fuel flow, maintaining a constant total fuel flow rate to prevent output reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If premixed combustion is used to suppress nitrogen oxides emissions, then nitrogen oxides emissions are reduced, but flame flashback and heat load increase occur
Solution Approach 1:
The combustor is divided into multiple independent burners (premixed burners and diffusion burners), each capable of operating independently. This segmentation allows the system to switch between combustion modes or operate in combination, mitigating the harmful effects of flame flashback in premixed combustion while maintaining low NOx emissions.
Solution Approach 2:
The invention combines premixed combustion and diffusion combustion systems in a single combustor. The premixed burners provide low NOx emissions while diffusion burners serve as backup to handle flame flashback conditions, creating a hybrid system that leverages the advantages of both combustion schemes.
2Reliability
If fuel flow rate is reduced to extinguish flame in premixer, then flame is extinguished, but output power of gas turbine is reduced
Solution Approach 1:
The system combines multiple fuel supply paths (premixed fuel system and diffusion fuel system) that can operate independently or in combination. When flame flashback is detected in the premixer, the diffusion fuel supply is activated to extinguish the flame while the premixed fuel supply is reduced, maintaining overall power output while ensuring safety.
Solution Approach 2:
The control system dynamically adjusts the fuel-air ratio parameters by switching between premixed and diffusion combustion modes. When flame flashback occurs, the system changes the combustion parameter from premixed mode to diffusion mode, which has different flame propagation characteristics, thereby extinguishing the flashback while maintaining power output.
3Use of energy by moving object
If temperature of flame is increased to improve gas turbine efficiency, then efficiency is improved, but nitrogen oxides emissions increase
Solution Approach 1:
The combustor employs dynamic control of the fuel-air mixture and combustion mode, allowing real-time adjustment between premixed and diffusion combustion based on operating conditions. This dynamic adaptability enables the system to maintain high efficiency while suppressing NOx emissions by selecting the appropriate combustion mode for each operating point.
Solution Approach 2:
The system changes the fundamental combustion parameter by switching between premixed combustion (low temperature, low NOx) and diffusion combustion (high temperature, high efficiency) modes. This parameter change allows the combustor to optimize for either efficiency or emissions control depending on operational requirements.
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
This solution effectively extinguishes flames within premixers, suppresses output power reduction, and enhances reliability and operability while controlling nitrogen oxides emissions by maintaining a stable fuel-air ratio and reducing heat load on combustor structures.
Implementation Method 1
at least one thermometer installed to be buried in one of the vanes
Implementation Method 2
a premixed burner by a premixed combustion scheme
Implementation Method 3
a diffusion burner by a diffusion combustion scheme
Implementation Method 4
a plurality of premixed fuel nozzles that are connected to the premixed fuel system and that inject a premixed fuel to the corresponding premixers
Data Source
AI summary
A flame produced within a premixer is promptly extinguished and a reduction in output power of a gas turbine associated with extinguishment is suppressed. In a gas turbine combustor including a diffusion burner and a premixed burner, the premixed burner is configured with a burner liner that surrounds the diffusion burner; a burner casing that surrounds the burner liner; a plurality of vanes that separate a cylindrical space between the burner liner and the burner casing into a plurality of premixers arranged side by side in a circumferential direction; a plurality of premixed fuel nozzles that inject a premixed fuel to the premixers; at least one thermometer installed to be buried in one of the vanes, and the like, and in a case in which a detection value of the thermometer exceeds a corresponding set value, an opening of each of premixed gas control valves is reduced and an opening of a diffusion gas control valve is increased in such a manner that a sum of flow rates of fuels supplied to the diffusion burner and the premixed burner remains unchanged.