Gas Turbine Burner Assembly Combustion Stability Emission Control
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Solution Overview
Problem
Existing burner assemblies for gas turbines face instability due to thermo-acoustic oscillations and struggle to balance combustion stability with emission control, as the secondary combustion portion is responsible for most polluting emissions and its kinetics are temperature-dependent, leading to limitations in fuel supply and stability.
Innovation Solution
A burner assembly with a main and secondary burner system, where the secondary burner has a configurable convective time differing from the main burner's, incorporating auxiliary burners to generate partially premixed diffusive combustion zones within the main combustion zone, and a control device to regulate fuel flow rates, ensuring stable combustion and compliance with emission limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If fuel flow rate to secondary portion is limited to reduce emissions, then polluting emissions are reduced, but combustion stability deteriorates
Solution Approach 1:
The invention makes the convective time of the secondary portion dynamically adjustable by varying the cross-sectional area of the fuel supply line. This allows the system to adapt the stabilizing effect of the secondary portion according to operating conditions, maintaining combustion stability while minimizing emissions through optimized fuel distribution.
Solution Approach 2:
The invention changes the physical parameter of convective time in the secondary portion by modifying the geometry of the fuel supply line (cross-sectional area). This parameter change enables independent control of the stabilizing effect from the emissions-generating combustion, allowing stability to be maintained without proportionally increasing emissions.
2Object-generated harmful factors
If fuel flow rate to main portion is reduced to lower emissions, then polluting emissions are reduced, but combustion instability increases
Solution Approach 1:
The invention segments the combustion system into distinct portions (main and secondary) with independently controllable fuel supply lines. The secondary portion is specifically designed with adjustable convective time to provide stabilization, while the main portion handles the bulk combustion. This segmentation allows independent optimization of each portion's fuel flow to balance emissions and stability.
3Stability of the object's composition
If secondary portion is designed to stabilize flame, then combustion stability is improved, but polluting emissions increase
Solution Approach 1:
The invention changes the physical parameter of convective time in the secondary portion by modifying the geometry of the fuel supply line (cross-sectional area). This parameter change enables independent control of the stabilizing effect from the emissions-generating combustion, allowing stability to be maintained without proportionally increasing emissions.
Solution Approach 2:
The invention makes the convective time of the secondary portion dynamically adjustable by varying the cross-sectional area of the fuel supply line. This allows the system to adapt the stabilizing effect of the secondary portion according to operating conditions, maintaining combustion stability while minimizing emissions through optimized fuel distribution.
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 solution achieves increased combustion stability and reduced emissions by modulating convective times and improving temperature distribution, allowing the burner assembly to operate within legal emission limits while accommodating capacity variations.
Implementation Method 1
auxiliary burners (24, 25) generating partially premixed diffusive combustion zones (27, 28) within said main combustion zone (12)
Implementation Method 2
auxiliary burners (24, 25) generating partially premixed diffusive combustion zones (27, 28)
Implementation Method 3
the delay time T and the convective time τ are bound by the following relation: T/Tperiod= f(τ, flame length, kinetic chemical reactions)
Implementation Method 4
a control device (19) to regulate a fuel flow rate to be supplied to the burner assembly (9)
Data Source
Figure 1
Figure 2
AI summary
A burner assembly (9) for a combustion chamber (4) of a gas turbine plant (1) is provided with: • a main burner (10) configured to produce a main combustion zone (12) having a main convective time (tp); • a secondary burner (11) configured to produce at least a secondary combustion zone (20) having a secondary convective time (ts); • the secondary burner (11) is configured so that the secondary convective time (is) is different from the main convective time (tp).