Gas Turbine Inlet Guide Vane Control for Combustion Oscillation
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Solution Overview
Problem
Gas turbines experience combustion oscillation when fuel temperature is low, which existing control methods, such as adjusting fuel or air flow rates, cannot always prevent, especially during startup or load changes due to insufficient heating by conventional heaters.
Innovation Solution
A gas turbine control device and method that includes a fuel temperature detection unit and an inlet guide vane control unit, where the opening degree of the inlet guide vane is increased when the fuel temperature deviation from a set temperature exceeds a threshold, to enhance air intake and prevent combustion oscillation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the heater is used to heat fuel to a set temperature, then the fuel temperature is improved, but during startup or low load operation the heat exchange medium temperature is too low to sufficiently heat the fuel
Solution Approach 1:
The control device changes the operating parameters of the compressor by adjusting the inlet guide vane opening degree. When fuel temperature is low, the inlet guide vane opening degree is increased to raise the compressor output, which indirectly heats the fuel through increased compression heating effects, ensuring sufficient fuel temperature even when heat exchange medium temperature is low during startup or low load operation.
2Stability of the object's composition
If flow rate adjustment is performed to reduce fuel temperature influence, then the combustion state is improved, but combustion oscillation cannot be avoided in all cases
Solution Approach 1:
The control device performs preliminary action by detecting fuel temperature in advance and adjusting the inlet guide vane opening degree before combustion oscillation occurs. When fuel temperature is detected to be low, the system proactively increases the inlet guide vane opening degree to raise compressor output and stabilize combustion, preventing oscillation rather than merely responding to it.
Solution Approach 2:
The control device implements feedback control by continuously monitoring fuel temperature and adjusting the inlet guide vane opening degree accordingly. The detected fuel temperature feeds back to the control unit, which automatically modifies the compressor operating parameters to maintain stable combustion and prevent oscillation, creating a closed-loop control system.
3Power
If the inlet guide vane opening degree is increased, then the compressor output is improved, but the system complexity increases
Solution Approach 1:
The control device utilizes the existing inlet guide vane mechanism, which is already part of the gas turbine system, and gives it an additional control function. By making the inlet guide vane opening degree adjustable based on fuel temperature detection, this existing component serves both its original airflow regulation purpose and the new function of controlling compressor output for fuel temperature management, avoiding the need for separate control mechanisms.
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
Effectively avoids combustion oscillation by increasing the opening degree of the inlet guide vane, shifting the operating point to a higher output side, thus preventing oscillation regardless of the nozzle pressure differential design, even when fuel temperature is low.
Implementation Method 1
The heater can heat the fuel to a predetermined set temperature by heat exchange with a heat exchange medium such as feedwater from a steam turbine
Implementation Method 2
a compressor for generating the compressed air
Implementation Method 3
a combustor that can combust fuel by mixing the fuel with compressed air
Data Source
AI summary
A gas turbine includes a combustor that can combust fuel, which can be heated by a heater, by mixing the fuel with compressed air generated by a compressor. The compressor includes an inlet guide vane for adjusting an amount of intake air. When a deviation between the temperature of the fuel at an outlet section of the heater and a set temperature of the heater exceeds a threshold value, the gas turbine control device controls the opening degree of the inlet guide vane to become larger than the opening degree when the deviation is equal to or smaller than the threshold value.