Parallel gas-liquid separators can receive unequal gas and liquid loads because of piping resistance, valve position, pressure differences, liquid distribution, vessel level, and fouling. One demister can therefore reach re-entrainment even when total plant flow is below the combined nominal capacity.

Comparing downstream liquid composition with scrubber liquid, condensate, wash water, or other potential sources can help identify the true origin of a carryover problem. Conductivity, marker ions, solvent composition, sampling location, evaporation, dilution, and chemical reaction must all be considered.

Sudden depressurization can flash liquid into vapor, creating simultaneous gas-flow and liquid-entrainment surges that overload a mist eliminator. Transient DP, liquid-level swell, drainage behavior, support loads, and possible reverse flow should be evaluated separately from normal operation.

Outlet nozzle position, size, and clearance above a mist eliminator can create strong local velocity differences even when average face velocity is acceptable. Side outlets, short plenums, and unequal multiple outlets can cause localized re-entrainment and fouling.

Raw mist eliminator differential pressure cannot be compared directly when gas flow, density, temperature, or liquid loading change. Clean load-specific baselines or normalized DP trends provide a better indicator of fouling, hydraulic flooding, and long-term separator condition.