Ultraviolet Degradation of BTX in Waste Gas: Effects of Photocatalysis and Ozone Premixing
Date
2013-01-31
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Abstract
The focus of this study is on potential modifications of ultraviolet degradation of BTX (Benzene, Toluene and Xylene) in waste gas. A considerable amount of such pollutants is emitted from glycol dehydrators in the natural gas sector. ThePhotolytic technique has been recognized as a promising technique to control BTX emissions to theenvironment. In this work the effectiveness of other alternatives such as photocatalytic technology and photolysis in the presence of ozone are studied. A simulation model developed for benzene photolysis in waste gas by Mahmoudkhani (2012) was extended to include photocatalysis on the reactor wall. The model was applied to a cylindrical reactor containing a 40 W amalgam UV lamp in the axis. The model predictions of photodegradation with 254 nm and 185 nm light irradiation was compared with a combination of photolytic and photocatalytic degradation. At air flow rates of 1 L/min and benzene mass flow rates ranging from 0.5 to 10 mg/min, a degradation efficiency of 77%-23% is predicted for the catalytic process. In comparison, the model of Mahmoudkhani (2012) predicted an efficiency of 95%-20% for the noncatalytic process. However, a maximum quantum yield (ϕ) of 6.67×〖10〗^(-4) was predicted for the photocatalytic process. This low value explains the lack of benefit predicted when a photocatalytic coating is applied. It is concluded that the photolytic approach is a feasible alternative to the photocatalytic approach, especially for low concentrations of benzene emissions from waste gas. Furthermore, adding ozone greatly improves the efficiency of the process. Modeling of photolytic degradation with ozone confirms the experimental results; however, the modeling slightly overestimates the efficiency. Based on energy requirement calculations, it is concluded that the lowest energy is consumed when combination of ozone premixing and condensation pretreatment along with UV photolysis is used.
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Engineering--Environmental
Citation
Atyabi, M. (2013). Ultraviolet Degradation of BTX in Waste Gas: Effects of Photocatalysis and Ozone Premixing (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/28547