Gas Turbine Combustor Water Injection for Hydrogen Flashback
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Solution Overview
Problem
Gas turbine assemblies face challenges in operating reliably with high proportions of hydrogen fuel due to increased reactivity, leading to flame flashback and elevated NOx emissions, particularly in sequential combustion cycles.
Innovation Solution
A combustor assembly with a sequential combustion cycle that incorporates a water/steam injection system, where water/steam is injected into the combustor units to increase the inert mass of the air/fuel mixture, mitigating peak flame temperatures and reducing the risk of flashback and NOx formation, allowing for the use of hydrogen fuel without compromising reliability or exceeding NOx emission limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If hydrogen fuel is used in sequential combustor units, then operational flexibility and fuel versatility are improved, but flame flashback risk and reliability deteriorate due to increased reactivity
Solution Approach 1:
Water/steam is introduced as an intermediary substance into the combustion process. The injection system delivers water/steam into the combustion chamber where it vaporizes and mixes with the air-hydrogen mixture, acting as a mediator that moderates the combustion reaction intensity and prevents flashback while allowing hydrogen operation
Solution Approach 2:
Water/steam injection creates an inerting effect in the combustion chamber. The vaporized water increases the inert mass fraction in the air-fuel mixture, reducing the oxygen availability and reaction intensity, thereby creating a less reactive environment that prevents flashback while maintaining combustion
2Adaptability or versatility
If hydrogen fuel is used in sequential combustor units, then fuel versatility is improved, but NOx emissions increase due to higher reactivity and longer post-flame residence time
Solution Approach 1:
Water/steam serves as an intermediary that modifies the combustion chemistry. By introducing water vapor into the combustion zone, it acts as a third body that interferes with the high-temperature oxidation reactions that produce NOx, while still allowing the hydrogen combustion to proceed
Solution Approach 2:
The water/steam injection creates an inerting atmosphere that reduces peak flame temperatures. The increased inert mass fraction lowers the adiabatic flame temperature, which directly reduces thermal NOx formation kinetics while maintaining operational flexibility with hydrogen fuel
3Reliability
If water/steam is injected into combustor units, then NOx emissions are reduced and flashback is prevented, but device complexity increases due to additional injection system
Solution Approach 1:
The water/steam injection system is designed to serve multiple functions simultaneously: it prevents flashback, reduces NOx emissions, and enables hydrogen fuel operation. This multi-functionality justifies the added complexity by addressing multiple technical contradictions with a single system
Solution Approach 2:
The injection system utilizes the existing high-temperature environment and gas flow within the combustor to automatically vaporize and distribute the water/steam. The hot combustion gases themselves serve to evaporate the injected water, reducing the need for additional heating equipment and simplifying the overall system
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 water/steam injection system effectively reduces NOx emissions and prevents flame flashback, ensuring the reliable operation of gas turbine assemblies when using hydrogen fuel, maintaining compliance with emission regulations and enhancing operational flexibility.
Implementation Method 1
water/steam is injected into the combustor units to increase the inert mass of the air/fuel mixture, mitigating peak flame temperatures
Implementation Method 2
water/steam is injected into the combustor units
Implementation Method 3
water/steam is injected into the combustor units to increase the inert mass of the air/fuel mixture
Data Source
Figure 1
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Figure 3~5
AI summary
A combustor assembly (3) for a gas turbine assembly (1) comprising: • at least one combustor unit (10) provided with a premix combustor (15); • a water/steam injection assembly (48) comprising a water/steam source (49) and a water/steam circuit (50) configured to supply water/steam to the at least one combustor unit (10) of the combustor assembly (3); the water/steam circuit (50) comprising, for each combustor unit (10), at least one injecting layout (53), which is arranged in at least one air channel (42; 44; 31) of the combustor unit (10).