Degradation of Non-methane Hydrocarbons in Cooking Fume by Wire Cylinder DC Corona Discharge

Abstract

In this paper, using a direct current (DC) corona discharge with a bee-slot wire-barrel construction, the degrading efficiency of non-methane hydrocarbons (NMHCs) was examined in terms of cooking temperature, duct gas flow rate, and discharge voltage. The amount of NMHCs produced was investigated under each condition of cooking temperature of 80–120 °C and cooking oils of soybean oil, peanut oil, canola oil and lard. When soybean oil was used as the cooking fume at a cooking temperature of 200 °C, the largest concentration of NMHCs was formed. In the degradation experiment, it was found that the corona discharge treatment effect was very good, which was proportional to the discharge voltage and inversely proportional to the cooking temperature and gas flow rate, and the treatment effect was the best when the discharge voltage was 34 kV, the cooking temperature was 120 ℃ and the gas flow rate was 25 m/s, the degradation rate reached 91.40%, and the degradation could meet the national emission standards. Meanwhile, the degradation mechanism of phenanthrene, anthracene and pyrene, which are more toxic and have larger concentration in the cooking fume, was analyzed. Furthermore, response surface optimization experiments were also conducted, and the best combination of the optimized factors was 34 kV input voltage, 127.7 °C cooking temperature, and 0.011 s treatment time.