Gas Turbine Startup Control via Compressor Mass Flow Manipulation
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Solution Overview
Problem
Conventional gas turbine startup systems often lead to rotating stall during compressor operation outside standard conditions, causing mechanical stresses and potential damage due to resonance with natural frequencies of compressor blades.
Innovation Solution
A system and method for controlling gas turbine startup by manipulating compressor mass flow and combustor fuel flow to shift the operating line, reducing rotating stall by minimizing mechanical stresses on compressor blades, and using drive components to compensate for torque reductions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional startup sequence is used with large gas flow and large fuel flow to bring turbine to steady state, then productivity is improved, but mechanical stresses increase due to rotating stall and resonance
Solution Approach 1:
The patent applies dynamics by making the fuel flow and compressor inlet guide vane angle adjustable and variable during startup. The control system dynamically modifies operating parameters based on rotor speed, transitioning from fixed conventional startup to adaptive startup that avoids rotating stall resonance conditions while maintaining productivity.
Solution Approach 2:
The patent changes physical parameters during startup by varying fuel flow rate and compressor inlet guide vane angle as functions of rotor speed. This parameter modification shifts the operating point away from the rotating stall region, reducing mechanical stresses on compressor blades while achieving steady state operation.
2Reliability
If operating line is shifted to reduce rotating stall, then reliability is improved, but torque reduction requires compensation
Solution Approach 1:
The control system uses feedback from rotor speed measurements to continuously adjust fuel flow and inlet guide vane angle. This closed-loop control ensures the operating line remains shifted away from rotating stall conditions while compensating for torque variations, maintaining both reliability and power output.
Solution Approach 2:
The control system acts as an intermediary between the compressor and combustor, coordinating adjustments in inlet guide vane angle and fuel flow to achieve the desired operating line shift. This intermediary control balances the trade-off between reliability improvement and torque maintenance.
Data Source
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AI summary
Systems and methods for controlling the startup of a gas turbine are described. A gas discharge component may be configured to discharge gas from a compressor component associated with the gas turbine. A fuel control component may be configured to control a fuel flow provided to a combustor component associated with the gas turbine. A drive component may be configured to supply a rotational force to a shaft associated with the gas turbine. At least one control device may be configured to (i) direct the gas discharge component to discharge gas from the compressor component, (ii) direct the fuel control component to adjust the fuel flow, and (iii) direct the drive component to rotate the shaft.