Analyze the curve of the flow meter
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This is the steam flow rate in the stripping tower; when automatic control is in use, the valve does move in response to fluctuations. I’m not sure what causes these fluctuations – let’s analyze what possibilities there are.
Has there been any change in the pressure difference before and after the valve? Is there any phenomenon of liquid carrying gas or gas carrying liquid?
There’s no major change; it’s low-pressure steam at 1 MPa. It shouldn’t be a gas-liquid mixture.
You can make the valve upstream of this control valve tighter, so that the opening degree of the control valve increases slightly; it’s likely caused by vibration of the valve core!
Check whether the manual control is stable; if there are no fluctuations during manual operation, it may be due to improper setting of the PID parameters
The valve core does not vibrate; it is indeed possible to see the valve moving up and down, and it moves only when there is a change in the air pressure indicated by the air pressure gauge.
When switched to manual mode, this kind of fluctuation can also occur.
Then check whether it’s due to fluctuations in the steam system, especially problems with the steam trap. Another possibility is an issue with the actuator of the control valve; try replacing it
You said that it’s more likely for steam to contain water; for measurement purposes, there is a significant difference between steam and water! But judging from his trend, he should bring not much – in small quantities, with frequent appearances!
Let’s handle it in this direction for now\ud83d\ude0a