Single-loop control problem
Thread Content
A valve with single-loop control is used to regulate the liquid level (automatic control), and it had been functioning smoothly until recently; however, it has suddenly become difficult to regulate the level, and even manual control fails to achieve proper level adjustment. Could everyone help analyze the reason for this?
Is it related to temperature and humidity? Many heavy oils used in refineries are very sensitive to temperature
Check whether the control valve has a bypass; if it does, it is recommended to use the bypass when conditions permit to see if the liquid level fluctuates. Meanwhile, use the DCS to send control signals in order to adjust the control valve, and then adjust the level gauge accordingly. After eliminating any issues with the instruments, address the causes related to the process and external factors.
First, check whether the process is being operated as usual, whether there are any changes in the operating conditions, and whether all process parameters remain the same as during normal operation. If no issues are found during this process inspection but fluctuations still occur manually, it is possible that there is a problem with the output circuit, such as faults in the control valve’s pneumatic system, valve positioners, or the control valve itself. For reference only.
It would be best to have a trend chart! After analyzing several
Generally, it is due to fluctuations in the liquid level, which cause large variations in the detection signal; as a result, the output regulation becomes unstable. In such cases, it is first necessary to identify the reasons for these liquid level fluctuations, resolve those issues, and then assess the condition of regulation~~
Analyze this issue from the perspectives of liquid level and control valves