High vessel liquid level can increase mist eliminator loading by reducing disengagement space, causing direct splash, restricting drainage, and intensifying foaming effects. Carryover correlated with level excursions should be investigated before modifying the demister.

Mist eliminators for HCl wet scrubbers should be selected from actual gas flow, temperature, HCl and liquid chemistry, droplet characteristics, liquid loading, fouling risk, pressure-drop allowance, vessel material, and support arrangement. Material compatibility alone does not determine the correct separator.

A visible scrubber stack plume does not automatically indicate mist eliminator failure. Water-vapor condensation, fine aerosol, chemical particle formation, and true liquid carryover can all produce visible emissions and require different solutions.

Conventional wire mesh mist eliminators can remove many fine droplets but should not automatically be assumed suitable for true submicron aerosol. Very small particles may require fiber-bed or multistage separation depending on aerosol size, fouling, pressure drop, and outlet requirements.

In vacuum systems, even modest mist eliminator pressure drop can raise upstream operating pressure and affect boiling temperature, vacuum capacity, energy demand, and throughput. Actual vapor volume, wet pressure drop, drainage, and fouling margin are therefore critical design inputs.