Gas Turbine Compressor Discharge Pressure Control
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Solution Overview
Problem
The existing control concepts for gas turbines in IGCC systems often lead to instabilities, particularly at the compressor outlet, causing fluctuations in air flow and pressure that can result in uncontrolled cascades, affecting the reliability and availability of the gas turbine and adjacent systems.
Innovation Solution
The method involves using the compressor discharge pressure as a control variable to regulate the gas turbine, setting a maximum rate of change for this pressure to prevent rapid fluctuations, thereby ensuring stable operation and avoiding instabilities. This is achieved by monitoring and controlling the compressor discharge pressure, which allows for more precise and rapid adjustments compared to traditional temperature-based control methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional temperature-based control methods are used to regulate the gas turbine, then the turbine outlet temperature can be maintained, but pressure fluctuations and instabilities occur at the compressor outlet
Solution Approach 1:
The control method changes the regulated parameter from temperature to pressure. By using compressor outlet pressure as the primary control variable instead of turbine outlet temperature, the system achieves stable pressure control while avoiding the instabilities that occur with traditional temperature-based control methods.
Solution Approach 2:
The control system implements feedback by continuously monitoring the compressor outlet pressure and adjusting the inlet guide vane position accordingly. This closed-loop control ensures that pressure fluctuations are detected and corrected in real-time, maintaining stable operation.
2Temperature
If the inlet guide vane position is adjusted to control turbine outlet temperature, then temperature regulation is achieved, but rapid pressure fluctuations and uncontrolled cascades occur
Solution Approach 1:
The control system takes preliminary action by regulating compressor outlet pressure before temperature fluctuations can develop into instabilities. By maintaining stable pressure at the compressor outlet through proactive control of the inlet guide vane, the system prevents the cascade of fluctuations that would otherwise occur.
Solution Approach 2:
The control method provides beforehand cushioning by limiting the rate of change of compressor outlet pressure. This prevents rapid pressure variations from occurring in the first place, cushioning the system against the development of instabilities and uncontrolled cascades.
3Stability of the object's composition
If manual intervention is used to block inlet guide vanes to prevent instabilities, then pressure fluctuations are reduced, but power control capability is lost
Solution Approach 1:
The control system enables self-service by automatically regulating compressor outlet pressure through the inlet guide vane without requiring manual intervention. The system monitors pressure fluctuations and adjusts the vane position autonomously, maintaining both stability and power control capability simultaneously.
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 safe and reliable operation of the gas turbine by preventing pressure fluctuations, maintaining constant turbine power, and reducing turbine outlet temperature fluctuations, thus enhancing the overall stability and reliability of the system, even during start-ups and load changes.
Implementation Method 1
The compressor usually consists of several impellers with compressor blades in an axial design. It converts the kinetic energy of the incoming air mass into the diffuser-shaped, i. H. expanding gaps between the compressor blades into pressure energy.
Implementation Method 2
When the engine is started, spark plugs ignite the fuel, after which combustion takes place continuously. The combustion raises the temperature again and the gas expands.
Implementation Method 3
The gases flowing out of the combustion chamber then hit a turbine, where their kinetic and thermal energy is converted into mechanical energy.
Data Source
Figure 1
Figure 2
AI summary
A method for operating a gas turbine (1) comprising a compressor (2), a combustion chamber (4), and a turbine (6) is intended to enable particularly safe and reliable operation of the gas turbine (1). Furthermore, a gas turbine (1) and a gas and steam turbine plant particularly suitable for carrying out the method are to be specified. For this purpose, the compressor discharge pressure (120, 128) is used as a control variable.