Turbomachine Combustor High Hydrogen Operation
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Solution Overview
Problem
Traditional gas turbine combustors are unable to efficiently burn high levels of hydrogen or pure hydrogen without experiencing flashback or flame holding conditions, which can cause damage, and fail to meet stringent emission regulations for NOx and other pollutants.
Innovation Solution
A method for operating a turbomachine combustor with a primary and secondary combustion zone, where a first mixture of air and hydrogen is injected into the primary zone, and a second mixture of air and hydrogen is injected as a cross-flow into the secondary zone, with a third fuel injected separately to ignite and mix with the combustion gases, maintaining a stable outlet temperature and preventing flashback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If high levels of hydrogen or pure hydrogen are burned in a traditional combustor, then NOx emissions are significantly reduced or eliminated, but flashback or flame holding conditions occur causing severe damage to nozzles
Solution Approach 1:
The combustor is divided into multiple zones (primary combustion zone, secondary combustion zone, and mixing zone) with different fuel injection points and mixture ratios. This segmentation allows the flame to be stabilized in the secondary zone while preventing flashback to the primary nozzles, enabling high hydrogen content operation without damage.
Solution Approach 2:
Different regions of the combustor are given different local characteristics: the primary zone uses a specific fuel-air mixture ratio suitable for stable combustion, while the secondary zone introduces additional hydrogen-rich mixture. This local differentiation allows each zone to optimize for its specific function, preventing flashback while maintaining high overall hydrogen content.
2Object-generated harmful factors
If traditional combustion systems burn high levels of hydrogen, then pollutant emissions are reduced, but flame migrates towards fuel nozzles causing severe damage
Solution Approach 1:
The system performs preliminary combustion in the primary zone with a controlled fuel-air mixture, then introduces additional hydrogen in the secondary zone. This preliminary action establishes a stable flame front before the high-hydrogen mixture is introduced, preventing uncontrolled flame migration toward the nozzles.
Solution Approach 2:
The secondary combustion zone acts as an intermediary between the primary nozzles and the high-hydrogen fuel supply. It provides a transition region where the flame can burn hydrogen-rich mixtures without directly exposing the primary nozzles to flashback conditions, thus mediating the harmful interaction.
3Object-generated harmful factors
If hydrogen concentration in fuel is increased to reduce emissions, then environmental compliance is improved, but combustion stability and temperature control become difficult
Solution Approach 1:
The system dynamically adjusts the fuel-air mixture ratio in different zones and the timing of fuel injection. By controlling the progression of combustion through multiple zones with varying mixture strengths, the system maintains stable outlet temperature despite high overall hydrogen content, which has different combustion characteristics than traditional fuels.
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
Enables the safe and efficient operation of gas turbines on high hydrogen concentrations, reducing NOx emissions and preventing damage from flashback conditions, while maintaining the required outlet temperature.
Implementation Method 1
The third fuel ignites and mixes with the first flow and the second flow of combustion gases
Implementation Method 2
a second mixture of air and a second fuel containing hydrogen is injected into the secondary combustion zone as a cross-flow
Data Source
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AI summary
A method of operating a combustor (17) of a turbomachine (10) on a total fuel input that contains a concentration of hydrogen that is greater than about 80% is provided. The method includes injecting a first mixture of air (15) and a first fuel (158) containing a first amount of hydrogen into the primary combustion zone (72) of the combustor (17) to generate a first flow of combustion gases (164) having a first temperature. The method further includes injecting, with one or more premix injectors (100), a second mixture of air (15) and a second fuel (160) containing a second amount of hydrogen into a secondary combustion zone (74) of the combustor (17) to generate a second flow of combustion gases (166) having a second temperature. The method further includes separately injecting a third fuel (162) into the secondary combustion zone (74) to generate a third flow of combustion gases (168) having a third temperature.