Study the Catalytic Effects of Precursors for PCDD/Fs Formation

• Main Authors: Chien-Cheng Chen, 陳建呈
• Other Authors: Chieh Lin
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/06786498972206022473

碩士 === 國立屏東科技大學 === 環境工程與科學系所 === 97 === The precursors of Dioxin, such as chlorophenols, chlorobenzenes, and polycyclic aromatic hydrocarbons are combined with fly ash surface, the role catalytic metals, and a condensation reaction to form Dioxin compounds. A powdered activated carbon injection is used to effectively control and adsorb dioxin compounds in the flue. However, when the exhaust of the previous reaction is disturbed, small particles of fly ash may re-enter the air pollution prevention equipment to form dioxin and furan. In this study, the bag house of a waste incinerator was used in laboratory simulations. The results of the study show that adding 0.2% trichlorophenol onto fly ash forms a PCDD/Fs concentration of 27.9 ng/g, whereas adding 0.5% chlorobenzene onto fly ash forms a PCDD/Fs concentration of 8.3 ng/g. Therefore, the addition of trichlorophenol is more favorable than chlorobenzene because the trichlorophenol forms a dioxin concentration that is 2.4 times greater. Furthermore, adding 0.1% pentachlorophenol onto the fly ash produces a PCDD/Fs concentration of 142.2 ng/g, and adding 0.2% pentachlorophenol produces a PCDD/Fs concentration of 166.0 ng/g. Compared to the aforementioned trichlorophenol, the pentachlorophenol forms a dioxin concentration that is at least 4.1 times greater. Up to now, pentachlorophenol most effectively treats dioxin-type compounds in the flue. Also, increasing the concentration of pentachlorophenol subsequently increases the adsorbed concentration of PCDD/Fs. Further simulation revealed that the addition of mercurydichloride and trichlorophenol increased the PCDD/Fs concentration from 27.9 ng/g to 111.5 ng/g. Certainly, the mercurydichloride triples the adsorption of dioxin compounds. In conclusion, adding chlorophenol compounds, chlorobenzene, diphenyl furans, and polycyclic aromatic hydrocarbons onto fly ash generated positive trends of PCDD/Fs adsorption. The addition of chlorophenol compounds and polycyclic aromatic hydrocarbons resulted in large positive trends of PCDDs species adsorption. The addition of chlorobenzene and dibenzofurans resulted in large positive trends of PCDFs species adsorption.