Gas Turbine Combustor Supplemental Burner NOx Reduction
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Solution Overview
Problem
Existing gas turbine combustors face challenges in reducing nitrogen oxides (NOx) emissions without increasing size and cost, as conventional methods often require large supplemental burners and can degrade thermal efficiency or shorten apparatus lifespan.
Innovation Solution
A compact gas turbine combustor design featuring a pre-mixing type supplemental burner with an introducing passage that deflects compressed air radially inward, enhancing turbulence and fuel mixing, and includes multiple fuel injection holes and guide pieces to produce uniform pre-mixed gas, reducing NOx emissions effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a pre-mixing type supplemental burner is provided to reduce NOx emissions, then NOx discharge amount is reduced, but the combustor size and construction cost increase due to the long pre-mixing duct required
Solution Approach 1:
The patent repositions the supplemental burner from the upstream portion to the downstream portion of the combustor cylinder, and orientates it perpendicular to the cylinder axis. This spatial reconfiguration allows the pre-mixing duct to be significantly shortened while still achieving effective NOx reduction, as the burner injects pre-mixed fuel-air mixture into the combustion zone from a different location and angle
2Object-generated harmful factors
If a pre-mixing type supplemental burner is provided to reduce NOx emissions, then NOx discharge amount is reduced, but the number of components and construction time increase
Solution Approach 1:
The patent integrates the supplemental burner structure with the combustor cylinder by providing the burner body that extends through the circumferential wall and using the cylinder wall itself as part of the pre-mixing duct. This merging of structures eliminates the need for separate, lengthy pre-mixing duct components, thereby reducing the total number of parts while maintaining the NOx reduction function
3Object-generated harmful factors
If water or steam is injected into the combustion chamber to lower flame temperature, then NOx discharge amount is reduced, but thermal efficiency is degraded and apparatus lifespan is shortened due to corrosion
Solution Approach 1:
The patent changes the approach from modifying combustion temperature through water/steam injection to controlling fuel-air mixture composition and distribution. By using a pre-mixing type supplemental burner that injects fuel and air in controlled proportions into the downstream combustion zone, the system achieves low NOx emissions through proper fuel-air ratio control rather than temperature suppression, thereby maintaining thermal efficiency and avoiding corrosion issues
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 compact design achieves significant NOx reduction while maintaining thermal efficiency and preventing backfire, with improved fuel mixing and uniform temperature distribution, thus avoiding costly enlargements and component increases.
Implementation Method 1
the introducing passage configured to deflect a part of the compressed air radially inward with respect to the combustor cylinder... so as to produce a pre-mixed gas in the introducing passage
Implementation Method 2
a plurality of guide pieces provided to the annular inlet port and configured to guide the compressed air toward a center of the inlet port
Implementation Method 3
a fuel nozzle configured to supply the fuel from a plurality of fuel injection holes to the compressed air which is introduced into the introducing passage so as to produce a pre-mixed gas in the introducing passage
Implementation Method 4
a gas turbine combustor adapted for combusting a fuel together with a compressed air supplied from a compressor and supplying a combustion gas to a turbine
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
This invention provides a gas turbine combustor including: a main burner at a head portion of a combustor cylinder; and a pre-mixing type supplemental burner at a downstream portion of the combustor cylinder and extending through a circumferential wall thereof. The supplemental burner includes: an introducing passage configured to deflect a part of the compressed air radially Inward, the compressed air flowing from an air passage between the circumferential wall of the combustor cylinder and a housing surrounding the circumferential wall toward the head portion of the combustor cylinder, and introduce the compressed air into the combustor cylinder; and a fuel nozzle configured to supply the fuel from fuel injection holes to the compressed air introduced into the introducing passage to produce a pre-mixed gas in the introducing passage.