Concentric Gaseous Fuel Nozzle for Low-NOx Gas Turbine Conversion
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Solution Overview
Problem
Existing gas turbine engines face challenges in converting to gaseous fuel operation without costly and complex combustor redesigns, particularly when transitioning from liquid fuel systems.
Innovation Solution
A gaseous fuel nozzle design featuring concentric inner and outer air injection passages and gaseous fuel passages, which minimizes recirculation zones and enhances fuel-air mixing, allowing for efficient operation with gaseous fuels and optional liquid fuel injection capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a combustor is completely redesigned to accommodate gaseous fuel, then gaseous fuel operation capability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The fuel nozzle is divided into separate functional components: a body portion with air injection passages and a cap portion with fuel injection passages. This segmentation allows the nozzle to be designed specifically for gaseous fuel while maintaining compatibility with existing combustor architectures, avoiding complete combustor redesign.
Solution Approach 2:
The fuel nozzle is designed to accommodate both gaseous fuel injection and liquid fuel injection capabilities through its structural configuration. The air injection passages and fuel injection passages work together to support multiple fuel types, providing universality without requiring separate specialized components for each fuel type.
2Ease of manufacture
If conventional liquid fuel nozzle design is used, then manufacturing simplicity is maintained, but gaseous fuel injection performance deteriorates
Solution Approach 1:
The nozzle design incorporates localized features specifically optimized for gaseous fuel injection: air injection passages positioned to create turbulence and mixing zones, and fuel injection passages configured for proper gaseous fuel distribution. These local modifications maintain overall manufacturing simplicity while ensuring reliable gaseous fuel injection performance.
Solution Approach 2:
The design utilizes pneumatic principles by incorporating air injection passages that introduce compressed air to mix with and atomize the gaseous fuel. This pneumatic assistance ensures proper fuel-air mixing and reliable injection performance while maintaining a relatively simple nozzle structure that can be manufactured using conventional processes.
3Ease of manufacture
If fuel injection passages are positioned without optimization, then manufacturing ease is maintained, but combustion efficiency and NOx formation control deteriorate
Solution Approach 1:
The air injection passages and fuel injection passages are positioned asymmetrically relative to each other within the nozzle body, creating an optimized flow pattern where air and fuel interact in a controlled manner. This asymmetric positioning promotes better mixing and combustion efficiency while reducing NOx formation, achieved through straightforward manufacturing processes.
Solution Approach 2:
The design incorporates air injection passages that introduce air from directions other than the primary fuel flow axis, creating three-dimensional mixing patterns. This multi-dimensional approach to passage positioning enhances combustion efficiency and controls NOx formation by ensuring thorough fuel-air mixing, while the passages themselves remain simple cylindrical features easy to manufacture.
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 nozzle configuration reduces NOx formation and flame holding, promoting efficient combustion and enabling seamless conversion to gaseous fuel operation without requiring extensive combustor modifications.
Implementation Method 1
The air that is discharged out the inner air injection passage outlet ports and out the outer air injection passage outlet ports surrounds the gaseous fuel that is discharged out the gaseous fuel injection passage outlet ports and pushes the gaseous fuel away from the gaseous fuel injection passage outlet ports. This promotes fuel-air mixing
Implementation Method 2
The air that is discharged out the inner air injection passage outlet ports and out the outer air injection passage outlet ports surrounds the gaseous fuel that is discharged out the gaseous fuel injection passage outlet ports and pushes the gaseous fuel away from the gaseous fuel injection passage outlet ports. This promotes fuel-air mixing and allows the fuel-air mixture to burn downstream of the fuel-air outlet port
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A gaseous fuel nozzle (112) includes a main body (302), a plurality of inner air injection passages (304) having inlet (314) and outlet (316) ports, a plurality of outer air injection passages (306) having inlet (318) and outlet (322) ports, and a plurality of gaseous fuel injection passages (308)having inlet (324) and outlet (326) ports. At least the gaseous fuel injection outlet ports (322) are disposed concentrically about an axis of symmetry (310) and between the plurality of inner air injection nozzle outlet ports and the plurality of outer air injection nozzle outlet ports.