title: Experimental and modeling study of de novo formation of PCDD/PCDF on MSW fly ash.
abstract: The effect of sulfur dioxide (SO2) on the formation of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) has been studied in an entrained-flow reactor (EFR) under simulated waste combustion conditions. A chlorination model based on conditional probability was employed to evaluate the homologue patterns of PCDDs and PCDFs. Results revealed that the presence of SO2 did not alter the formation pathway although SO2 suppressed PCDD/F formation. The prediction model of PCDF showed good agreement with the experimental data (R = 0.95), whereas the prediction for PCDDs did not correlate well with the experimental data. This may be explained because potential chlorination pathways play a significant role in PCDF formation, whereas PCDDs are mainly formed through condensation reactions. Furthermore, the result indicated that the steric hindrance during formation has more effects on PCDD than on PCDF due to the symmetric molecular structures of PCDDs.
authors.affiliation: State key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou 310027, China. lixd@cmee.zju.edu.cn
authors.forename: Xiao-dong
authors.initials: XD
authors.lastname: Li
authors.forename: Ji
authors.initials: J
authors.lastname: Zhang
authors.forename: Jian-hua
authors.initials: JH
authors.lastname: Yan
authors.forename: Ke-fa
authors.initials: KF
authors.lastname: Cen
authors.forename: Shawn P
authors.initials: SP
authors.lastname: Ryan
authors.forename: Brian K
authors.initials: BK
authors.lastname: Gullett
authors.forename: Chunwai
authors.initials: C
authors.lastname: Lee
mesh_terms: D001572:Benzofurans / Q000138:chemical synthesis*; D002244:Carbon / Q000737:chemistry*; D060729:Coal Ash; D000072338:Dibenzofurans, Polychlorinated; D008962:Models, Theoretical; D052638:Particulate Matter / Q000737:chemistry*; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000138:chemical synthesis; D013458:Sulfur Dioxide / Q000737:chemistry*
chemical_list: D001572:Benzofurans; D060729:Coal Ash; D000072338:Dibenzofurans, Polychlorinated; D052638:Particulate Matter; D000072317:Polychlorinated Dibenzodioxins; D013458:Sulfur Dioxide; D002244:Carbon