Gas Turbine Cooling Control Method for Emission Reduction
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Solution Overview
Problem
Existing control methods for cooling turbine stages in gas turbines fail to accurately adjust cooling air consumption based on power output and turbine load, leading to inefficiencies and increased emissions, as they do not account for blade degradation and varying air consumption curves over time.
Innovation Solution
A control method that optimizes cooling air consumption by adjusting the opening of a valve based on measured pressures, temperatures, and load conditions, maintaining a constant expansion ratio to ensure efficient cooling while minimizing emissions, and can be implemented without structural alterations to the secondary-air circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cooling air consumption is increased to protect turbine components, then reliability is improved, but efficiency deteriorates due to reduced combustion airflow and increased nitric oxide emissions at high loads
Solution Approach 1:
The control system dynamically adjusts cooling air consumption based on real-time operating conditions (load, temperature, pressure). The method transitions from static design-specification cooling to dynamic adaptation, where cooling air flow is continuously optimized according to actual blade temperature measurements and turbine load conditions, resolving the contradiction between reliable protection and energy efficiency
Solution Approach 2:
The invention implements feedback control by measuring actual blade temperatures and using this information to adjust cooling air consumption. Temperature sensors provide real-time data on blade thermal state, which feeds back to the control system that then modulates cooling air flow accordingly, ensuring minimum necessary cooling without excessive energy loss
Solution Approach 3:
The control method changes operational parameters (cooling air flow rate, valve opening) based on measured blade temperatures and turbine conditions. By dynamically adjusting these parameters rather than maintaining fixed cooling rates, the system achieves optimal balance between component protection and combustion efficiency across varying operating conditions
2Loss of energy
If cooling air consumption is reduced to improve efficiency, then energy loss is decreased, but reliability deteriorates due to insufficient cooling and increased carbon monoxide emissions at low loads
Solution Approach 1:
Feedback control ensures that cooling air consumption is reduced only when blade temperatures indicate sufficient cooling. Temperature measurements provide continuous feedback to prevent excessive cooling at low loads while maintaining energy efficiency, automatically adjusting flow to match actual thermal needs rather than following fixed consumption curves
Solution Approach 2:
The turbine cooling system serves itself by using measured blade temperature conditions to determine appropriate cooling levels. The system autonomously adjusts cooling air flow based on its own thermal state measurements, eliminating the need for conservative over-cooling and achieving energy efficiency without compromising reliability
3Ease of operation
If fixed cooling air consumption based on design specifications is used, then ease of operation is improved, but adaptability deteriorates due to inability to account for blade degradation and varying operating conditions
Solution Approach 1:
The control system uses feedback from temperature sensors and load measurements to automatically adapt cooling air consumption to actual operating conditions and blade degradation states. This maintains ease of operation through automated control while achieving high adaptability to varying turbine conditions without requiring manual intervention or complex operator judgment
Solution Approach 2:
The system performs self-adjustment by using its own operational data (temperature measurements, load conditions) to determine appropriate cooling levels. This self-service capability provides both ease of operation through automation and adaptability to changing conditions, eliminating the trade-off between simple control and flexible response
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 improves efficiency and power output at high loads, reduces emissions at low loads, and extends the lifespan of thermally stressed turbine components by maintaining optimal operating temperatures and air flow, ensuring reliable operation.
Implementation Method 1
adjusting the opening of a valve based on measured pressures, temperatures, and load conditions, maintaining a constant expansion ratio
Implementation Method 2
adjusting the opening of a valve based on measured pressures, temperatures, and load conditions
Implementation Method 3
cooling a turbine stage in a gas turbine... maintaining optimal operating temperatures... to protect the thermally stressed parts of the turbine
Data Source
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AI summary
A control method for cooling a turbine stage (20) of a gas turbine (1), whereby cooling air is bled from combustion air flowing in a compressor (2) of the gas turbine (1), and is fed to a cooling circuit (55) staring from a stator (22) of the turbine stage (20); and cooling airflow is adjusted as a function of the pressure (POair) at the inlet of the cooling circuit, and as a function of the combustion air pressure (Pcomp) at the exhaust of the compressor (2); more specifically, there is a feedback control setting a setpoint, which is predetermined as a function of the power output (P) of the turbine (4) to reduce contaminating emissions.