Syngas Combustor Flashback Prevention via Fuel Blending
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Solution Overview
Problem
Conventional premixed dry-low nitrogen oxide (NOx) combustion systems for gas turbines experience flashback when combusting syngas due to its low Modified Wobbe Index (MWI) and high fuel reactivity, leading to hardware damage, and existing solutions that avoid flashback, such as diffusion combustors with nitrogen injection, increase complexity and cost.
Innovation Solution
A method and apparatus that blend syngas with natural gas to create a fuel mixture with a higher MWI and lower reactivity, reducing the likelihood of flashback by slowing the characteristic chemical time of the fuel, thereby preventing damage and simplifying the combustion system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional premixed DLN combustion systems are used to combust syngas, then the system structure is simple, but flashback occurs due to low MWI and high fuel reactivity
Solution Approach 1:
The patent changes the chemical composition parameters of the fuel by blending syngas with natural gas. This adjusts the MWI and characteristic chemical time parameters of the fuel mixture, slowing the reaction rate and preventing flashback while maintaining system simplicity
Solution Approach 2:
The patent creates a composite fuel mixture by combining syngas and natural gas in specific proportions. This composite fuel has intermediate properties that balance the low MWI/high reactivity of syngas with the higher MWI/lower reactivity of natural gas, eliminating flashback without requiring complex system modifications
2Reliability
If diffusion combustors with nitrogen injection are used to avoid flashback, then flashback resistance is improved, but system complexity and cost increase
Solution Approach 1:
The patent extracts the nitrogen injection system and diluent injection mechanism from the combustion system. By using fuel blending instead of diluent injection, the system eliminates the need for separate nitrogen supply lines, compression equipment, and injection devices, significantly reducing complexity
Solution Approach 2:
The patent uses natural gas as an intermediary substance to mediate between the combustion requirements and flashback prevention needs. The natural gas acts as a buffer that slows reaction kinetics without requiring additional system components for diluent injection
3Object-generated harmful factors
If steam injection systems are used to control NOx formation, then NOx emissions are reduced, but system complexity and cost increase due to water quality requirements
Solution Approach 1:
The patent replaces the complex steam injection system with a simpler fuel blending approach. Instead of requiring expensive steam generation equipment and water treatment systems, the solution uses readily available natural gas as a permanent component of the fuel mixture, achieving NOx control without the infrastructure of a steam 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 blended fuel mixture effectively reduces flashback occurrences, maintains NOx control without additional diluents, and decreases system complexity and cost by utilizing readily available natural gas, ensuring stable combustion and extended hardware lifespan.
Implementation Method 1
mixing the first and second gaseous fuels together to form a blended gaseous fuel
Implementation Method 2
a nozzle in flow communication with the combustion zone for injecting a blended gaseous fuel into the combustion zone
Implementation Method 3
Combustion systems of at least some known gas turbine engines combust synthesis gas, or syngas, to create exhaust gases that drive a gas turbine
Data Source
AI summary
A method for operating a combustor is provided. The method includes supplying a predetermined amount of a first gaseous fuel to the combustor, wherein the first gaseous fuel has a first Modified Wobbe Index (MWI) and a first fuel reactivity, and supplying a predetermined amount of a second gaseous fuel to the combustor, wherein the second gaseous fuel has a second MWI that is lower than the first MWI and a second fuel reactivity that is higher than the first fuel reactivity. The method also includes mixing the first and second gaseous fuels together to form a blended gaseous fuel, and injecting the blended gaseous fuel into the combustor.