Double-flange level gauge
Thread Content
The hydrogenation light fractionation tank for crude oil has stable inflow and outflow rates, as well as relatively stable temperature and pressure; the instruments are functioning properly, though there are significant fluctuations. Currently, it is under manual control
Low score? There’s not much pressure either; just remove it, clean the flange surface, and realign it again.
Due to the unstable reaction, the inflow and outflow amounts are not stable, right?
Based on the information available currently, 1. Check the material of the diaphragm box; in hydrogen environments, ordinary 316 diaphragm boxes are prone to hydrogen embrittlement； 2. The diaphragm box is covered with dirt, resulting in static pressure fluctuations on one side ； 3. Check the flange spacing of the double flanges; too small a distance can lead to inaccurate measurements. Please provide the relevant process flow and process parameters next time, to facilitate issue analysis.
Stable material inflow and outflow do not necessarily mean a stable liquid level, as vapor-liquid separation causes the liquid level to fluctuate quite significantly.
Having trouble with the level gauge? If it’s not certain, it might be due to inappropriate DCS parameter settings for the hydraulic control valve; is the flow rate also fluctuating significantly?
Will the liquid level not fluctuate if it is controlled manually? If that’s the case, try adjusting the PID parameters
How is the manual mode working at the moment? If the liquid level remains stable when adjusting it manually, then considering adjusting the PID parameters is necessary. If there are still fluctuations even when adjusting manually, it is first necessary to check whether there are variations on the glass plate display; also determine whether the double-flange transmitter needs to be taken apart to clean its diaphragm box, followed by resetting the parameters
Is the back-pressure (stripper) pressure stable?
The table represents a new table, namely remote transmission fluctuations; it involves two remote transmission instruments