High mist carryover combined with unexpectedly low pressure drop can indicate perimeter bypass, open segment joints, displaced mesh, damaged vane modules, or an incorrect replacement separator. Low DP should therefore be compared with the historical clean baseline rather than assumed to indicate good condition.

Fiber-bed mist eliminators capture fine and submicron aerosols through a combination of Brownian diffusion, interception, inertial impaction, coalescence, and drainage. They typically require lower face velocity and careful control of pressure drop, liquid properties, solids, and fouling.

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.