Gas Turbine Exhaust Temperature Control via Pressure Ratio
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Solution Overview
Problem
Traditional gas turbine control systems are limited in their ability to achieve accurate firing temperature control, combustion parameter control, and exhaust emissions control, particularly when operating with varying fuel compositions and loads.
Innovation Solution
A method and system that determine the turbine exhaust pressure and pressure ratio to calculate the exhaust temperature, identifying a reference exhaust temperature curve for optimal operation and maintaining the operating point on this curve, allowing for precise control of the gas turbine's operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional control systems use scheduling algorithms to adjust fuel flow and inlet guide vanes, then the gas turbine can operate safely within known boundaries, but the control accuracy of exhaust temperature and combustion parameters deteriorates
Solution Approach 1:
The patent changes the control parameters from traditional scheduling-based inputs (fuel flow, IGV position) to a direct exhaust temperature versus compressor pressure ratio relationship. This parameter transformation enables more accurate control by using the actual exhaust temperature measurement and compressor pressure ratio as the primary control variables, rather than relying on pre-defined schedules that may not account for real-time variations in fuel composition and operating conditions.
2Reliability
If the control system follows established scheduling algorithms, then the operation remains within known boundaries, but the ability to adapt to varying fuel compositions and loads deteriorates
Solution Approach 1:
The patent implements feedback control by continuously measuring the exhaust temperature and compressor pressure ratio, comparing the actual operating point to the reference exhaust temperature curve, and adjusting control inputs to maintain optimal operation. This closed-loop feedback mechanism enables the system to adapt to varying fuel compositions and loads in real-time, rather than relying on open-loop scheduling algorithms that cannot respond to changing conditions.
Solution Approach 2:
The patent transitions from static scheduling algorithms to a dynamic control approach where the exhaust temperature versus compressor pressure ratio relationship is continuously updated and maintained. The control system dynamically adjusts fuel flow and other parameters based on real-time measurements, allowing the gas turbine to adapt its operating characteristics to match varying fuel compositions and load conditions while maintaining optimal efficiency and emissions performance.
Data Source
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AI summary
Gas turbine, software and method for controlling an operating point of the gas turbine that includes a compressor, a combustor and at least a turbine. The method includes determining a turbine exhaust pressure at an exhaust of the turbine; measuring a compressor pressure discharge at the compressor; determining a turbine pressure ratio based on the turbine exhaust pressure and the compressor pressure discharge; calculating an exhaust temperature at the exhaust of the turbine as a function of the turbine pressure ratio; identifying a reference exhaust temperature curve in a plane defined by the exhaust temperature and the turbine pressure ratio; and controlling the gas turbine to maintain the operating point on the reference exhaust temperature curve.