Mist eliminators remove liquid droplets from gas, while “coalescer” is a broader term that may describe gas-liquid or liquid-liquid equipment. Wire mesh, vane, fiber-bed, cartridge, and liquid-liquid coalescers are not interchangeable even when their names sound similar.

Mist eliminator performance tests can be inaccurate if droplet sampling is nonrepresentative. Probe velocity, sampling location, droplet inertia, condensation, sample-line losses, gas-volume basis, and stable operating conditions all affect the validity of carryover and efficiency measurements.

An upstream mist eliminator can protect a WESP by removing coarse droplets and bulk contaminated liquid before the electrostatic stage handles fine aerosol and particulate. The benefit depends on inlet liquid loading, solids, pressure drop, gas distribution, and wash-system interaction.

Pulp and paper bleach-plant mist eliminators may be exposed to corrosive liquid, fibers, salts, and suspended solids. Fine mesh can bridge and foul, so open geometry, washing, drainage, pressure-drop monitoring, and maintenance access are important for long-term reliability.

Electroplating and chrome-plating scrubber demisters may handle both ordinary scrubber droplets and much finer process aerosol. Chemical resistance, low pressure drop, fouling control, ventilation airflow, washability, and correct aerosol measurement are all important.