Gas Turbine Combustion System with Premixed Pilot Flame Stabilization
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Solution Overview
Problem
Gas turbines suffer from moderate polluting emissions due to the presence of diffusion-type flames, which are characterized by high temperatures and contribute significantly to nitrogen oxide emissions.
Innovation Solution
A combustion system with premixed fuel injection pilot devices that mix fuel gas with a turbulent air stream before injection into the combustion chamber, creating a homogeneous fuel-air mixture to stabilize the main flame and reduce polluting emissions by avoiding diffusion flames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If diffusion-type flames are used for stabilizing the main flame, then flame stability is improved, but polluting emissions (nitrogen oxides) increase due to high temperatures
Solution Approach 1:
The invention changes the combustion mode from diffusion-type to premixed-type combustion by pre-mixing fuel and air in a mixing chamber before injection. This parameter change in the combustion process reduces flame temperature while maintaining stability through the structured injection system with multiple nozzles arranged in specific patterns.
Solution Approach 2:
The invention performs preliminary mixing of fuel and air in a dedicated mixing chamber before the combustion process. This pre-mixing action ensures homogeneous fuel-air mixture is injected into the combustion chamber, eliminating the need for diffusion-type flames and reducing nitrogen oxide emissions while maintaining flame stability.
2Object-generated harmful factors
If premixed fuel injection is used to reduce emissions, then nitrogen oxide emissions decrease, but flame stability may be compromised
Solution Approach 1:
The invention segments the fuel injection system into multiple nozzles with different injection patterns (central nozzle for main fuel, peripheral nozzles for pilot fuel). This segmentation allows the premixed system to maintain flame stability through distributed injection points while keeping overall emissions low by avoiding diffusion flames.
Solution Approach 2:
The invention introduces a mixing chamber as an intermediary component between fuel storage and combustion chamber. This intermediary device ensures thorough premixing of fuel and air before injection, enabling the system to achieve both low emissions and stable combustion through the homogeneous mixture.
3Productivity
If high temperature diffusion flames are used, then combustion efficiency is improved, but component durability decreases due to thermal stress
Solution Approach 1:
The invention changes the temperature parameter by using premixed combustion instead of diffusion combustion. This parameter change reduces maximum flame temperature while maintaining combustion efficiency through optimized fuel-air mixing and injection patterns, thereby reducing thermal stress on components and improving durability.
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 system achieves reduced nitrogen oxide emissions and improved flame stability, with lower maximum flame temperatures and decreased oscillations within the combustion chamber, enhancing combustion efficiency and component durability.
Implementation Method 1
a pilot device for stabilizing the main flame, characterized by premixing of the fuel gas with a turbulent stream of air
Implementation Method 2
The flame is stabilized by a series of pilot flames with premixed fuel gas
Data Source
AI summary
Combustion system (10) for a gas turbine equipped with a premixing chamber (12) for air which is mixed with the fuel injected from a series of holes (11) creating a main central flame which is formed in a flame tube (14), the premixing chamber (12) is convergent towards a connection end with a combustion chamber comprising the flame tube (14), the combustion system (10) comprises a series of pilot devices (20) with premixing of the fuel gas, which create a series of corresponding pilot flames suitable for stabilizing the main central flame itself, at the same time reducing the polluting emissions.