Venturi Scrubber
The air stream emitted into the atmosphere, generated by production activities, can include both Volatile Organic Substances (VOCs) and dust and particulate matter from gaseous streams.
Among all wet scrubbers, Venturi scrubbers are chosen for their greater efficiency in removing these pollutants.
Its function is performed through the use of water; purification occurs during the contact phase between the washing liquid and gaseous substances.
Operation of a Venturi Scrubber
Venturi scrubbers consist of two elements:
- The venturi in which the contact phase between liquid and the air to be de-dusted is produced.
- The Cyclone Separator where the separation between the air and the droplets that have captured the dust is carried out.
Dusty air, sucked in by a fan, passes through a narrow section and undergoes a considerable increase in velocity, whilewater, recirculated by a pump, is fed into the throat.
The air-water mixture tangentially enters the cylindrical separator.
Centrifugal force pushes the water droplets against the wall surface, while the dusted air escapes upward.
- Pressure drops in particulate removal: between 200 and 1000 mm/H2O
- Gas passage velocity in the throat: between 30 w and 120 m/s.
The flow is sent to a lamellar decanter: this results in the separation of the flocs, which, burdened, are unable to rise along the lamellar surface and are deposited at the bottom of the decanter, which has a conical shape.
The specific shape allows the sludge flakes to reach a thickening degree of 4%.
Clarified water flows out of the upper section of the decanter. A paper filter is often placed downstream of a decanter: if some sludge flocs were to escape from the decanter, they would be blocked by the decanter.
The Venturi Scrubber, having no filter parts to replace, requires little maintenance, related almost uniquely to the tank under the tower.
If, in addition to pollutants of an inorganic nature, pollutants of an organic nature were present, biological purification should be carried out.
Benefits
- High levels of reliability
- Low maintenance
- No fire hazard
- Low investment
The separation of powders with this type of plant is particularly carried out when the matter to be separated is hygroscopic or has peculiarities that exclude the Dry Process.
High effectiveness is achieved even when powders have been made as a result of combustion, drying, steam systems or mixing and agitation filling steps.
Coind manufactures Venturi Scrubber plants sized according to pollutant concentration, flow rate and flue gas temperature.
To achieve high abatement levels, several towers are planned side by side, including proportional volumes of the liquid used.
