||Volatile organic compounds (VOCs) can be considered as a major source of air pollution, and in many cases, legislation has already been introduced to reduce their emissions. O-xylene, one of VOCs, is widely used in industry as solvent and also the raw material of o-Phthalic anhydride (PA). The subjects of this research are divided into four parts, they are screening activity of catalysts, incineration efficiency with various operation parameters, physical properties of catalysts and kinetic model derivation.|
In screening activity of catalysts, Four kinds of metal ions (Cu, Mn, Zn, Fe; the molar ratio of metal/Fe is 1/2), three different temperature (70℃, 80℃, 90℃) and pH (9, 10, 11) were the parameters of FP to manufactured 36 ferrospinel catalysts. Under the same reaction conditions (o-xylene conc.=1600 ppm, GHSV=71150 hr-1, O2=21%, temperature=298K~673K), it’s found that the most efficient catalyst was Cu/Fe ferrospinel and its synthesis condition was pH at 9 and temperature at 90℃.
The operation parameters to determine incineration efficiency were temperature at 373K ~ 673K, inlet o-xylene concentration at 600 ~ 1600 ppm, GHSV at 47450 ~ 71150 hr-1, O2 concentration at 21 ~ 40%. The results showed that the conversion was proportional to the increase of inlet o-xylene concentration, temperature and inlet oxygen content and was inverse proportional to the increase of GHSV.
To realize the physical properties of catalysts, XRD, SEM and EDS were applied. The results indicated that there was no physical difference between fresh and used catalysts.
Besides, two kinetic models, Power rate law and Mars-Van Krevelen model were used to demonstrate the decomposition of o-xylene. It’s discovered that Power rate law was more reasonable to illustrate the catalytic o-xylene oxidation. Further, the reaction rate was increased with the increase of inlet o-xylene and oxygen concentration and reaction temperature.