Sequential Combustor Fuel Line Connection for Hydrogen Operation
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Solution Overview
Problem
Current gas turbine systems face challenges in using highly reactive fuels like hydrogen due to increased NOx emissions and flashback risks, which limit fuel flexibility and efficiency, especially when operating with sequential combustors.
Innovation Solution
The method involves switching off some burners and operating the remaining burners in a hybrid mode combining diffusion and premix combustion, with a high diffusion fuel rate, and using a connection between the gas and oil fuel lines to reduce pressure and safely feed high reactive gas fuel into the oil fuel line, allowing for the use of hydrogen-based fuels without detrimental effects on combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If highly reactive fuel like hydrogen is fed into the combustor, then fuel flexibility and efficiency are improved, but NOx emissions increase and flashback risk increases
Solution Approach 1:
The combustor is divided into multiple zones with different combustion modes. Some burners operate in premix mode while others operate in diffusion mode, allowing the system to segment the combustion process to reduce NOx emissions while maintaining fuel flexibility for hydrogen-based fuels.
Solution Approach 2:
Different regions of the combustor are assigned different combustion characteristics. The premix burners provide low NOx emission zones while diffusion burners provide stable flame zones, creating local quality variations that collectively solve the NOx emission problem while enabling highly reactive fuel usage.
2Adaptability or versatility
If highly reactive fuel like hydrogen is fed into the combustor, then fuel flexibility is improved, but flashback risk increases
Solution Approach 1:
The combustor system is segmented into multiple burners with different operational modes. By switching between premix and diffusion burners, the system can maintain stable combustion and prevent flashback while accommodating highly reactive hydrogen-based fuels, thus improving fuel flexibility without compromising reliability.
Solution Approach 2:
The combustor system dynamically switches between different burner configurations and combustion modes based on operating conditions. This dynamic adaptation allows the system to maintain optimal combustion stability and prevent flashback while using highly reactive fuels, thereby improving fuel flexibility without increasing flashback risk.
3Object-generated harmful factors
If diluents are added to reduce NOx emissions, then NOx generation is reduced, but combustion efficiency decreases
Solution Approach 1:
Instead of adding diluents to the entire combustor, the system segments combustion into premix and diffusion zones. The premix burners inherently produce lower NOx emissions through controlled mixing, while diffusion burners maintain high combustion efficiency, eliminating the need for diluents and preserving overall combustion productivity.
4Reliability
If pressure is increased to safely feed high reactive gas fuel, then fuel delivery safety is improved, but system complexity increases
Solution Approach 1:
A pressure reduction connection is introduced as an intermediary element between the gas fuel line and the burners. This intermediary component safely manages the high reactive gas fuel by controlling pressure transitions, enabling reliable fuel delivery without requiring complex high-pressure system modifications throughout the entire fuel delivery infrastructure.
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 approach reduces NOx generation levels and allows for safe operation with high hydrogen content fuels, maintaining combustion efficiency and flexibility without the need for diluents, thereby extending the lean blowout margin and lowering inlet temperatures.
Implementation Method 1
The first combustor is configured for receiving the compressed air and mixing this air with fuel and combusting the mixture
Implementation Method 2
the downstream second combustor (or reheat combustor) configured for receiving the hot gas leaving the first combustor and adding fuel into this hot gas for performing a self/spontaneous ignition
Data Source
Figure 1~2
Figure 3~6
AI summary
A sequential combustor for a gas turbine ; the sequential combustor comprising: - a first combustor provided with a plurality of first burners fed by compressed air and configured for injecting fuel in the compressed air in a diffusion mode and in a premix mode, each first burners comprises at least a gas fuel nozzle fed by a gas fuel line and at least a liquid fuel nozzle fed by a liquid fuel line; - a second combustor provided with a plurality of second burners fed by hot gas leaving the first combustor and configured for injecting fuel in the hot gas; wherein the combustor moreover comprises a fluidly connection configured for selectively connecting the gas fuel line and the liquid fuel line for allowing part of gas fuel running in the gas fuel line to enter in the liquid fuel line and to be injected by the liquid fuel nozzle.