PP and PVDF mist eliminators require mechanical review as well as chemical compatibility review. Lower stiffness, thermal expansion, and long-term creep can cause sagging, vane-spacing changes, compression, and bypass if support and restraint are not designed correctly.

Differential-pressure monitoring can reveal mist eliminator fouling and hydraulic changes, but incorrect pressure tap location, nearby internals, turbulence, blocked impulse lines, or condensation can distort the reading. Instrument layout should be reviewed before diagnosing the separator.

Mist eliminator wash systems can prevent fouling, but excessive or poorly distributed wash liquid can cause flooding, high pressure drop, and re-entrainment. Wash rate, nozzle coverage, gas load, drainage capacity, and cleaning strategy should be designed together.

Fouling patterns on a mist eliminator can reveal gas maldistribution, liquid channeling, direct spray impingement, wall flow, drainage obstruction, and upstream packed-bed problems. Photographing and mapping deposits before cleaning can provide valuable process-diagnostic information.

Edge gaps between a mist eliminator and vessel wall can create low-resistance gas bypass paths, causing liquid carryover even when the active separator performs correctly. Actual vessel dimensions, ovality, segmentation, support, and thermal movement should all be considered.