Extract from
The American Society Of Mechanical Engineers

www.asme.org
 ESP units can be highly efficient at removing submicron particles, but they require continuous maintenance to retain their efficiency. They require periodic cleaning of the plates and wires, plus monitoring (replacement and/or adjusting) of the transformer and electrical circuitry. The possibility of fire and explosion of electrical devices used near or within an oil aerosol is a hazard that should be given ponderous consideration before select-ing an electrostatic precipitator for oil mist removal. Indeed the potential hazards of the ESP unit eliminate them from consideration in many oil mist removal situations.

Other devices employing mechanically induced centrifugal force and combinations of mesh and filters have displayed limited removal efficiency.
In general, they have succumbed to decreasing efficiency with time, frequent and costly maintenance of the mechanically moving apparatus, sealing problems, and the need for frequent replacement of components.
Meanwhile, their success in submicron mist removal remains limited.

FIBER BEDS
Fiber bed mist eliminators use Brownian movement to coalesce and remove mist particles. They are designed and fabricated specifically to coalesce and remove submicron particles. When the design is correctly adjusted for the parameters of the specific application, fiber beds can achieve 99+% -- even to up to 99.99% -- removal of submicron (0.3 to 0.5 µ diameter) particles.

An early application of fiber bed mist eliminators was the removal of aerosol mists from vapors in sulfuric acid plants, where the submicron aerosol mists generated by the process can be highly corrosive and toxic. High re-moval efficiency required to protect equipment and the atmosphere. Fiber bed mist eliminators have been suc-cessfully removing submicron mists in this service for many years.

The proven technology and equipment for removing submicron mists from sulfuric acid plants was a natural solution to the LOV problem. After modifying the design to account for differences in the particle size distribu-tion curve, concentration of particles, differential pressure limitations, density of liquid, and total load, the fiber bed was successfully applied to removing LOV mist. In fact, for control of emissions from lubrication oil vents, fiber bed mist eliminators fall into the Environmental Protection Agency category of “Best Available Control Technology”.

Fiber bed mist eliminators achieve and maintain their high efficiency at high loads with a very low differential pressure. The required differential pressure is usually between 2 to 4 in. (51 to 102 mm) W.C. for installations that operate without a fan, or 6 to 10 in. (152 to 254 mm) where a fan is needed to maintain a negative pressure on the reservoir.

In the solids-free application of LOV oil mist removal, fiber beds can maintain their original high removal effi-ciency during a virtually unlimited, maintenance-free service life. They have been demonstrating these trouble free characteristics for many years.
Abstract  |  Particle Size  | Collection Methods  |  Fiber Beds  |  Collection Efficiency  |  Benefits
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