Gas coolers and aftercoolers can generate substantial water or hydrocarbon condensate even when the upstream gas contains no droplets. Downstream separation should account for peak condensate rate, actual gas density, bulk-liquid removal, mist polishing, piping drainage, and any further cooling after the separator.

Carbon-capture absorbers can emit mechanically entrained amine droplets, much finer aerosol, and vapor. Conventional mesh or vane demisters may control coarse droplets but may not solve aerosol-dominated emissions, especially where fine particulate or acid aerosol provides condensation nuclei.

Differential thermal expansion between vessel shells, frames, supports, and mist eliminator media can create operating-temperature bypass gaps, compression, warping, and drainage problems. Large plastic or mixed-material assemblies should therefore be reviewed across the full temperature range.

Droplet evaporation upstream of a mist eliminator can reduce liquid mass while shrinking droplets into a more difficult size range for inertial separation. Temperature, gas saturation, residence time, liquid volatility, and dissolved solids can therefore change the actual demister inlet duty.

Gas viscosity affects the aerodynamic drag on droplets and therefore influences how easily they follow gas streamlines instead of impacting demister wires or vane surfaces. Its effect becomes especially relevant for fine droplets, unusual gases, high temperatures, and transfer of air-water test data to process conditions.