Variable Jet Nozzle for Gas Turbine Fuel Flexibility
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current gas turbine combustors face challenges with fuel flexibility, combustion instability, and high maintenance costs due to the use of multiple fuels like natural gas and DME, which require complex retrofitting and result in noxious emissions and backfires, especially during low-load operations.
Innovation Solution
A dual fuel nozzle with a variable jetting hole diameter is designed, featuring swirling wings, a switching plate, and a driving unit that allows for the selection and adjustment of fuel types and flow rates, enabling simultaneous use of multiple fuels like natural gas, DME, and coal gas, ensuring stable combustion and reduced emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a dual fuel system is implemented to apply multiple fuels (natural gas, DME, coal gas) to a gas turbine, then fuel flexibility is improved, but combustion instability and backfire occur due to different fuel characteristics
Solution Approach 1:
The fuel jetting system is segmented into multiple independent channels, each with dedicated jetting holes for different fuel types (natural gas, DME, coal gas). The nozzle body includes separate fuel injection holes for each fuel type, allowing independent control and optimization of each fuel's combustion characteristics, thereby maintaining stability when switching between different fuels
Solution Approach 2:
The patent implements a variable jetting hole diameter mechanism where the jetting hole size can be dynamically adjusted based on the fuel type being used. This allows the system to optimize the fuel-air mixture ratio for each specific fuel (natural gas, DME, or coal gas), ensuring stable combustion conditions regardless of the fuel's inherent characteristics
2Adaptability or versatility
If the jetting hole diameter is fixed, then the device structure is simple, but fuel flexibility and adaptability to different fuel types are reduced
Solution Approach 1:
The nozzle incorporates a variable jetting hole diameter mechanism that allows dynamic adjustment of the hole size based on the fuel type. This dynamic capability enables the system to adapt to different fuel characteristics (natural gas, DME, coal gas) without requiring multiple fixed-nozzle designs, balancing adaptability with manageable complexity
Solution Approach 2:
The dual fuel nozzle is designed as a universal component that can handle multiple fuel types (natural gas, DME, coal gas) through a single integrated structure. The nozzle includes multiple fuel injection channels and a variable diameter mechanism that serves all fuel types, eliminating the need for separate nozzle designs for each fuel and reducing overall system complexity
3Object-generated harmful factors
If lean premixed combustion method is used to suppress thermal NOx production, then emission is reduced, but combustion instability and flame backfire occur due to low fuel-to-air ratio (10% or less)
Solution Approach 1:
The nozzle design creates different local combustion conditions within the same system. The variable jetting hole diameter allows for localized enrichment of the fuel-air mixture in specific regions, creating stable flame anchors while maintaining overall lean premixed conditions for NOx suppression. This local quality variation enables simultaneous achievement of low emissions and combustion stability
Solution Approach 2:
The system performs preliminary mixing of fuel and air in a controlled manner before combustion, ensuring proper mixture preparation. The multiple fuel injection channels and variable diameter holes enable pre-combustion optimization of the fuel-air ratio, stabilizing the lean premixed flame before it enters the combustion chamber, thereby preventing backfire while maintaining low NOx emissions
4Adaptability or versatility
If independent channels with different fuel jetting holes are used for heavy oil and natural gas, then fuel switching capability is improved, but device complexity and maintenance cost increase
Solution Approach 1:
The dual fuel nozzle is designed as a universal component that integrates multiple fuel injection channels (natural gas, DME, coal gas) into a single nozzle body. This multi-functional design allows the system to switch between different fuel types without requiring separate nozzle assemblies, reducing device complexity while maintaining fuel switching capability
Solution Approach 2:
The patent merges the injection channels for different fuel types into a single integrated nozzle structure. The nozzle body combines multiple fuel injection holes and a variable diameter mechanism that serves all fuel types, consolidating what would otherwise be separate systems into one unified component, thereby reducing maintenance requirements and structural complexity
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 enhances fuel flexibility, reduces combustion instability and emissions, decreases maintenance costs by allowing easy fuel switching, and extends the life of gas turbine parts by stabilizing the flame and preventing backfires, thus improving overall combustion efficiency and reducing noxious exhaust.
Implementation Method 1
a plurality of swirling members which swirl and discharge the gas introduced from a gas introduction hole
Implementation Method 2
a first jetting member which is installed at the other side of the duct and includes a plurality of first jetting holes for jetting a first fuel
Data Source
AI summary
A dual fuel nozzle (10) of a gas turbine combustor with a variable jetting hole diameter is disclosed. The combustor includes a plurality of swirling wings (110) disposed along an outer peripheral surface of a central shaft (120) to have at least one main fuel jetting hole, an air duct (112) positioned at the lower side of the swirling wings (110) to supply air to the swirling wings (110), a pilot fuel injection hole (124) and jetting hole formed to pass through a central portion of the central shaft (120) to supply a pilot fuel, a switching plate (130) disposed inside the swirling wings (110) to vary the size of the main fuel jetting hole, a driving unit (140) disposed to be connected to the switching plate (130) to move a position of the switching plate (130), and a casing (160) containing the swirling wings (110), the air duct (112), the switching plate (130) and the driving unit (140). It is possible to enhance fuel flexibility in a multiple fuel system for applying two or more fuels to a gas turbine at the same time.