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Photo-Oxidation in bypass


Odour abatement  with the power of UV light !



1. Oxidation Process description

2. Cyclo-Photo-Oxidation

3. Applications

4. Advantages of photo- oxidation in bypass

5. References


1. Photo-Oxidation in Bypass: Oxidation Process description 

Photo-Oxidation in bypass consists in injecting in the contaminated emission oxygen radicals (O*, OH-,) produced by treating ambient air with lamps emitting short UV-C waves (100 to 280nm).



(1): emission inlet

(2): bypass modules contaiming UV-C lamps

(3): mixing chamber + fan

(4): emission outlet



At 185 nm, oxygen molecules are converted in ozone (O3) and at 254 nm ozone is converted in oxygen radicals (O*); in presence of water, ozone builds hydroxyl radicals (OH-):


                                       3 O2 + hn (185nm)   2 O3

                                       O3  +  hn  (254nm)   O2 + O*

                                       O3 + 2 H2O   4 OH- 

Since the flow of photo-oxidised air is much lower than the emission flow (around 10-20% of the emission flow), this system is financially interesting for high flow emissions. The efficiency of this oxidation process increases with the temperature.


2. Cyclo-Photo-Oxidation for heat recovery 

If the emission is saturated with humidity and contains other contaminants like oil aerosols, it is recommended to install a Cyclonic Heat Exchanger on its upstream side in order to remove as much particulate material as possible in order to avoid the adsorption of the oxygen radicals on their surface. This concept is called "Cyclo-Photo-Oxidation" 



Veurne Snack Foods (B)

3. Applications 

  • Photo-Oxidation in bypass is recommended for hot emissions (T>60C) and high flow rate emissions., as long as the VOC concentration does not exceed 40mg/m3

4. Advantages of photo- oxidation in bypass 

  • low investment, energy (lamp, fan) and maintenance costs, even for high flow rates
  • long equipment life time
  • No start-up time; no fluid supply and waste production, except condensate if any

5. References 

on request


© 2008 Air Quality Concept