Air Pollution Control Systems
Wet scrubber is used for air pollution control. The principle of wet scrubbers is that the dust laden air or gas is brought in contact with fine droplets of scrubbing liquid which is usually water, in a high turbulent zone which is created in a ventury. Due to high velocity and high turbulence the fine dust in the air or gas gets mixed with the scrubber liquid and the air or gas becomes dust free. The scrubber liquid is then separated from the air or gas in a droplet separator which has a tangential entry and uses the centrifugal force for separation. The secondary separation is done by passing the air or gas through demister pads. Provision for automatic flushing of demister pads is made using multiple spray nozzles above it. There a different variations available in scrubber design depending upon the concentration of dust in the air or gas and the permitted emission level. Technodry scrubbers are specially designed to handle the most critical emission norms with high efficiency and low operating cost.
Bag filter is used as an efficient air pollution control system. Bag filter consists of a housing with multiple filter bags or cartridges mounted in it. The filter bags or cartridges are made of material suitable for operating temperatures and products being handled. The dust laden air or gas passes through the filter media and gets filtered. The mechanism to dislodge the dust adhering to the filters is either reverse pulse jet using compressed air/nitrogen or mechanical shaking using pneumatic cylinders. Fine particles having size as low as 0.1 microns can be filtered thus making it possible to achieve emission levels as low as below 10ppm.