Fuel Split Control for Gas Turbine Combustion Stability
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Solution Overview
Problem
Existing combustion devices in gas turbine engines face challenges in maintaining stable operation and reducing emissions across varying fuel compositions and loads, leading to potential instabilities and overheating, especially when switching between different fuels or blending fuels with changing chemical compositions.
Innovation Solution
A method that selects a predefined operational band of fuel split settings based on the heating value of the fuel and adjusts the pilot fuel split schedule according to engine load and combustion stability parameters, using predefined boundary curves to define a range of acceptable operating points, allowing for reliable operation across different modes and fuel types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If medium calorific value fuels (MCV fuels) or low calorific value fuels (LCV fuels) are used to reduce NOx emissions, then emissions are reduced, but combustion stability deteriorates
Solution Approach 1:
The fuel supply system is segmented into multiple injection points with different functions: pilot fuel injection points for stable combustion and main fuel injection points for power generation. This segmentation allows the system to use LCV/MCV fuels for emission reduction while maintaining stability through dedicated pilot fuel injection.
Solution Approach 2:
The system dynamically adjusts the fuel split ratio (parameter) between pilot fuel and main fuel based on operating conditions and fuel calorific value. By changing this parameter, the system maintains combustion stability across varying fuel compositions while achieving emission reduction goals.
2Device complexity
If the fuel split setting is predefined based on calculations and engine testing, then control simplicity is improved, but adaptability to changing fuel composition deteriorates
Solution Approach 1:
The control system incorporates feedback from sensors monitoring combustion stability parameters (pressure oscillations, flame characteristics) and fuel properties (calorific value, composition). This feedback enables automatic adjustment of the fuel split setting, allowing the system to adapt to changing fuel composition while maintaining stable operation.
Solution Approach 2:
The fuel split setting transitions from a static predefined value to a dynamic parameter that automatically adjusts based on real-time operating conditions and fuel composition. This dynamic adjustment mechanism maintains combustion stability across varying conditions without requiring complex manual reconfiguration.
3Reliability
If multiple fuel injection points with individual fuel supply amounts are provided, then combustion stability is improved, but device complexity increases
Solution Approach 1:
The fuel injection system uses a universal control mechanism that manages multiple injection points through a common control logic and actuation system. This multi-functional approach allows a single control system to coordinate pilot fuel and main fuel injection, reducing overall system complexity while maintaining the stability benefits of multiple injection points.
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
This approach ensures stable and reliable operation of gas turbine engines by maintaining a stable fuel split setting within defined boundaries, reducing the frequency of control method changes and minimizing emissions, even when fuel composition changes, thereby enhancing engine performance and safety.
Implementation Method 1
both being supplied to the combustion device for being combusted to a combusted fluid
Data Source
AI summary
A method, control unit and rotating machine for determining a fuel split setting value for adjusting a fuel split setting for a combustion device, the fuel split setting defining a relation between main fuel and pilot fuel. The method includes: retrieving a first information item correlated to heating value of supplied main fuel; retrieving a second information item correlated to combustor operating condition; retrieving at least one third information item representing stability of combustion; selecting a predefined pair of minimum and maximum boundary curves for the fuel split setting from a plurality of predefined pairs based on the first and second information items, the minimum and maximum boundary curves defining a band of fuel split settings permitted for a range of second information item values; determining the fuel split setting value within the selected pair of minimum and maximum boundary curves based on the third information item.