Mist eliminators consist, generally of 2 types - diffusion and impaction style designs. Impaction mist eliminators can be vertical fiber bed elements, a metal mesh pad horizontal design or of chevron staggered plate construction. MECS offers Brink diffusion and impaction fiber beds and TowerGARD mesh pad mist elimination products. Since fiber bed mist eliminators are the most versatile and can be designed to remove any liquid or any soluble solid mist from any gas stream, the emphasis here will be on high efficiency fiber bed mist eliminators.
Fiber bed mist eliminators consist of thick layers of very fine fibers placed between two concentric cylindrical screens or cages. Chemically resistant glass fibers, synthetic fibers and other special type fibers are used as the fiber bed material, depending on the process environment. Structural screen/cage parts and flanges are made of any weldable metal, plastic or glass reinforced resins.
All fiber bed mist eliminators operate in a similar manner. Gases containing mist particles are directed horizontally through the fiber bed and the mist particles collect on the individual fibers within the fiber bed and coalesce to form liquid films. These liquid films are then moved through the fiber bed by the gas flow, then the liquid drains off the downstream face of the fiber bed by gravity. Fiber bed mist eliminators are typically installed in a vessel or tank and the collected liquid is continuously drained from within the tank.
A fiber bed design innovation is the addition of a second more coarse fiber layer on the downstream side. This additional layer expedites drainage and prevents re-entrainment of the liquid back into the gas stream