Air Purification techniques

The function of air quality management is checking of emissions. The control - technology or control measurements describes the apparatus, processes which reduces air pollution. The emission reduction depends on the technology or
process. In general the technologies or processes which the reduces the pollution the best are placed in areas with the largest pollution. The choice of the control technology depends on the environment, technique, economic factors and the type of pollutant. There are 2 types of emissions, i.e. particulate emissions and gaseous emissions. For these 2 types of emissions there are also 2 types of emission-reduction techniques, i.e. particulate-purification techniques and gas purification techniques.

Particulate-Purification techniques

Particulate purification techniques concentrates at catching the particles which are transmitted by a pollution source. There are several factors that play a role at selecting a purification technique. The characteristics of the particles in the exhaust flow influence the choice of purification technique. These characteristics are the particle size, flow of the exhaust flow, the temperature, the humidity, and several chemical properties such as explosion limits, acidity, alkality, and combustibility.
Following techniques are applied at purifying particles from a polluted air flow:

Sedimentation chamber (Gravity separator)
Cyclone separator
Rotating scrubber
Venturi scrubber
Spray chamber
Dry electro filter
Wet electro filter
Cloth filter
Ceramic filter
Absolute filter
Demister

Gas- Purification techniques

The methods for controlling gaseous pollutants is the use of techniques to recover or destroy polluting substances. There are 4 commonly used technologies for gaseous pollutants: absorption, adsorption, condensation, and combustion (flare). The choice of technology depends on the pollutants that must be removed, purification efficiency, the characteristics of the polluted gas flow, and specific characteristics of the place. Absorption, adsorption, and condensation are recovery techniques whereas combustion implies the destruction of the pollutant.
Following techniques apply at purifying pollutants from the air flow:

Condensation
Cryocondensation
Regenerative adsorption (active carbon, zeolite, polymere adsorption)
Dry and semi-dry lime absorption
Gas scrubbing (acid, alkaline scrubber, wet lime scrubbing, basic oxidating scrubbing, biofilter, biotricklingfilter and water scrubber)
Thermic combustion (Recuperative, regenerative thermic oxidation)
Catalytic combustion (Recuperative, regenerative catalytic oxidation)
Flaring
Foto-oxidation
Ionization
Selective non catalytic reduction (SNCR)
Selective catalytic reduction (SCR)

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