Shutdown and maintenance process after liquid flooding in the distillation tower
If the adjustment is ineffective or if the following situations occur, parking is required:
The pressure difference continues to exceed the normal value by 200% for 1 hour;
Zero liquid level at the bottom of the tower accompanied by abnormal metal noise (suspected of internal component damage).
Maintenance steps:
Safety isolation: Cut off the feed and replace the combustible gas with nitrogen.
System pressure relief: pressure reduction rate ≤ 0.1MPa/min, cooling rate ≤ 2 ℃/min.
Internal inspection:
Dismantle the tower plate to detect deformation/blockage (with a focus on checking for detachment of the float valve or coking of the sieve holes);
Check the levelness of the liquid distributor in the packed tower (deviation ≤ 2mm/m).

Emergency operation control after liquid flooding in distillation tower
Load regulation
Reduce gas phase load: Immediately reduce the steam volume of the bottom reboiler (decrease by 20% -30%), and control the rising steam flow rate to be below the liquid flooding critical value.
Reduce liquid phase load: pause or reduce the feed rate (to below 50% of normal value) to alleviate liquid accumulation in the downcomer.
Reflux ratio regulation: Stop product extraction and switch to full reflux mode to maintain tower balance.

Parameter recovery monitoring
Real time tracking of pressure difference changes: When the pressure difference drops back to the normal value (such as 0.5-3kPa/tray) and stabilizes for more than 15 minutes, the sign is initially relieved.
Detect the liquid level at the bottom of the tower/reflux tank: gradually resume feeding after the liquid level fluctuation disappears;