Blog – Industrial Scrubbers

Wet scrubbers for air pollution emission control 

Scrubber is an air pollution control device  that can be used to remove some particulates or gases from industrial exhaust streams. It is a pollution control device which uses liquid to wash unwanted pollutants from a gas stream. Industrial Scrubbers can also be used for heat recovery from hot gases by flue gas condensation. Scrubber are used for scrubbing fumes such as silicon tetrafluride, HNO3, HCl, NH3, Phosphoric acid, super phosphate & Fluorine.

Wet scrubber vs Dry scrubber

Wet Scrubber 

Wet scrubber  is a device that removes pollutants from a furnace flue gas or from other gas streams. In wet scrubbers, the polluted gas stream is brought into contact with the scrubbing liquid, by spraying it with the liquid, by forcing it through a pool of liquid so as to remove the pollutants. Wet scrubbers remove pollutant gases by dissolving or absorbing the pollutants into the liquid.

Dry scrubber :

A dry Scrubbing system does not saturate the flue gas stream that is being treated with moisture. In some cases no moisture is added; while in other only the amount of moisture that can be evaporated in the flue gas without condensing is added. Dry scrubbers generally do not have wastewater handling/disposal requirements. Dry scrubbing systems are used to remove acid gases(such as SO2 and HCl) primarily from combustion sources

Wet scrubber working principle 

Wet scrubbers relay on the liquid spray to remove dust particles from the gas stream. It is also for the fume absorption and so very useful in fume extraction systems. It removes air pollutants by inertia of diffusional impaction, reaction with absorbent or reagent slurry or absorption into a liquid solvent. The inlet gas stream usually enters the bottom of the tower and moves upward, while liquid is sprayed downward from one or more levels.

Wet scrubber efficiency & design parameters 

The factors influencing the scrubber efficiency  can be  determined from the DOE requirements. These factors includes irrigation area, scrubbing liquid, bed depth, liquid flow rate, temperature, material of construction, packing, maintenance, liquid to gas ratio and heat effect.

Design Parameters

• Contaminant solubility
• Vapor pressures
• Wash liquid flow rate