Wet scrubber.

Description

Wet scrubber. 

inertial separators had the drawback of dust particles not accumulating properly on the collecting surface, resulting in finer particles being swept back into the air stream. Air washers or scrubbers, use liquid (usually water) to absorb the finer dust particles ( scrubbed). Water comes into contact with the dust filled air stream & captures dust in water droplets. The dirty water droplets accumulate, & are collected & removed. The cleaned air in air washers contains fine water droplets forming a mist. These water droplets can be removed from the cleaned air by a mist eliminator.

    mist eliminators are similar in design to inertial separators where mist & air are separated either by change in air flow or by the spin in air stream which creates the centrifugal forces. The dust – water mixture is either cleaned or recycled into the scrubber. The accumulated dust is removed by using a clarification tank or a drag chain tank, where dust particles can be cleaned after they settle to the bottom.

the three important operations of air washers or wet gas scrubbers:

      humidification (of air): this process increases size of fine dust particles & makes collection easier.  

contact of liquid & dust filled air: this is the key operation that governs collection efficiency of the scrubber. Whater droplets in the path of the air stream collect dust particles while the air stream flows around it.

 separation of dirty liquid & clean air: during this operation, the dust – water mixture accumulates, & as they grow larger, they collect into the hopper.

 how do wet scrubbers work?  

 in the simplest form of air scrubbers, water is sprayed on the interior walls of the cyclone to improve collection efficiency. Water thus mops up fine dust particles that otherwise do not stay on the collection surfaces & tend to be swept back into the air stream. However air scrubbers suffered operational problems of

keeping the interior walls coated,

maintaining water distribution on interior walls and

cleaning mud & sludge from collection interior.