Gas Turbine Combustor Pilot Fuel Injector Relocation
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Solution Overview
Problem
Existing combustors for gas turbines face issues with high temperatures at the pilot burner surface, leading to reduced life cycle and increased nitrogen oxides (NOx) emissions, which are not adequately addressed by previous solutions.
Innovation Solution
A combustor design featuring a radial swirler with an annular array of vanes, a pre-chamber with a peripheral wall passage for pilot fuel injection, and a pilot fuel injector located between the inner and outer panels, allowing for pilot fuel injection directly into the combustion chamber, creating a marginally higher air/fuel ratio and reducing NOx emissions through enhanced turbulence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pilot fuel is injected into the pre-combustion chamber close to the pilot burner surface, then combustion control is achieved, but local temperature at the pilot burner surface increases reducing life cycle
Solution Approach 1:
The pilot fuel injector is repositioned from the traditional location on the pilot burner surface to a new location in the pre-combustion chamber away from the burner surface. This spatial relocation in a different dimension (distance from surface) allows the pilot fuel to be injected into the oxidant flow path where it can be effectively mixed and combusted without creating high temperature zones at the pilot burner surface, thus extending its life cycle while maintaining combustion control.
2Reliability
If pilot fuel is injected close to the pilot burner surface, then combustion control is achieved, but nitrogen oxides emissions increase
Solution Approach 1:
By relocating the pilot fuel injector to a position away from the pilot burner surface and into the oxidant flow path, the combustion process is shifted to occur in a different spatial location. This allows the pilot flame to be stabilized in the pre-combustion chamber where it can control the main combustion process without directly generating high temperature zones that produce nitrogen oxides, thus reducing harmful emissions while maintaining flame control.
3Power
If oxidant gas flows through the swirler mixing with main fuel, then main combustion is achieved, but pilot fuel injection positioning becomes critical for temperature control
Solution Approach 1:
The combustion process is segmented into two distinct zones: the main combustion zone where oxidant gas mixes with main fuel through the swirler, and the pilot combustion zone where pilot fuel is injected into the oxidant flow path. This segmentation allows the pilot fuel injector to be positioned in the pre-combustion chamber away from the pilot burner surface, enabling independent optimization of both main combustion power and pilot burner durability without interference between the two combustion processes.
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 design reduces temperatures at the pilot burner surface, increases the pilot burner's life cycle, and stabilizes combustion across a wide load range while minimizing NOx emissions by moving heat release and diffusion flames away from the pilot burner face.
Implementation Method 1
a swirler arrangement (140) comprising a swirler (103)... in use a first portion F1 of the oxidant gas F flows through the outlet of the swirler mixing with a main fuel flow
Implementation Method 2
A second portion F2 of the oxidant gas F is channelled through the passage and mixes with a pilot fuel flow from the pilot fuel injector
Implementation Method 3
enhanced turbulence... moving heat release and diffusion flames away from the pilot burner face
Data Source
Figure 1
Figure 2~3
Figure 4A~4C
AI summary
The present invention relates to a combustor (100) for a gas turbine, comprising: a pre-combustion chamber (101) having a peripheral wall (115) around a centre axis (35) of the pre-combustion chamber (101), the peripheral wall (115) comprising an inner panel (61) and an outer panel (62) and a passage (60) provided between the inner and the outer panels (61, 62), a swirler (103) which is connected to the pre-combustion chamber (101) for providing pre-combustion chamber (101) with a flow (F) of an oxidant gas, at least a pilot fuel injector (112), wherein the swirler (103) is connected to the peripheral wall (115) in such a way that a portion (F2) of the oxidant gas (F) from the swirler (103) is channelled to the passage (60), and the pilot fuel injector (112) is connected to the passage (60) for injecting a flow of pilot fuel into the passage (60).