Valve Control Unit for Multi-Stage Compressor IGV Sticking
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Solution Overview
Problem
In multi-stage compressors, abnormal states such as IGV sticking lead to unstable plant operations due to sudden signal changes and excessive force application, deteriorating controllability without adequate countermeasures.
Innovation Solution
A valve control unit outputs open/close signals with a predetermined difference or stores signals during malfunction determination, limiting changes to prevent instability and maintain controllability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the valve control unit continuously outputs signals to adjust IGV opening degree during abnormal states, then the controllability is improved, but excessive force is applied to the stuck IGV causing potential failure
Solution Approach 1:
The valve control unit acts as an intermediary between the control signal and the stuck IGV. When valve malfunction is detected, it mediates by limiting the degree of opening change to a predetermined value or less, preventing excessive force from being directly applied to the stuck IGV while still maintaining some control capability.
Solution Approach 2:
The control system changes the parameter of signal output by limiting the degree of opening change to a predetermined value or less when malfunction is detected. This parameter modification allows the system to maintain controllability while preventing harmful excessive force application to the stuck valve.
2Speed
If the system allows sudden signal value changes during abnormal states, then the response speed is improved, but the overall plant becomes unstable
Solution Approach 1:
The valve control unit prepares for potential instability by beforehand cushioning sudden signal changes. When valve malfunction is detected, it limits the degree of opening change to a predetermined value or less, cushioning the impact of signal changes on the overall plant and preventing instability while still maintaining responsive control.
3Device complexity
If the system reduces the number of operation ends of IGV opening degree control when IGV is stuck, then the device complexity is reduced, but the controllability is deteriorated
Solution Approach 1:
The valve control unit is designed with multi-functionality to handle both normal operation and abnormal stuck conditions. It can detect valve malfunction, determine when the IGV is stuck, and automatically adjust its control strategy by limiting degree of opening changes, maintaining controllability without requiring separate complex control systems for different operating conditions.
Data Source
AI summary
A multi-stage compression system in which gases compressed by a pair of first-stage compressors are compressed by subsequent compressors connected to the first-stage compressors in series includes a valve control unit configured to output open/close signals for opening/closing valves for adjusting flow rates of gases flowing into the first-stage compressors provided at inlet sides of the first-stage compressors. The valve control unit outputs an open/close signal having a difference less than or equal to a predetermined value with respect to a degree of opening of the valve before malfunction determination as the open/close signal until a malfunction is eliminated after the determination of the malfunction in which one of the valves does not have a degree of opening according to the open/close signal.