Ammonia scrubbers can create ammonium salt solutions and fine reaction aerosol that foul mist eliminators through evaporation and crystallization. Separator geometry, wash strategy, chemistry, pressure-drop monitoring, and material selection should therefore be evaluated together.

Mist eliminator design margin should reflect gas-flow variation, liquid loading, fouling, maldistribution, data uncertainty, and operating cases rather than an arbitrary universal safety factor. Excessive oversizing can also create low-velocity performance and cost problems.

Mist eliminators in cold climates can suffer icing in mesh, vane passages, drains, and wash systems. Freezing can block gas area, prevent drainage, raise pressure drop, and damage components during freeze-thaw cycles, especially during shutdown.

High-velocity droplets, slurry, and abrasive particles can erode vane mist eliminators, especially at leading edges, bends, and liquid pockets. Erosion can alter blade geometry and drainage even when the material remains chemically compatible.

Mist eliminator drain lines need proper hydrostatic sealing and pressure balance so that liquid can leave without allowing process gas to blow through the drainage path. Incorrect seal height, backpressure, vessel level, or drain blockage can cause liquid holdup and re-entrainment.