title: Suppression of dioxins by S-N inhibitors in pilot-scale experiments.
abstract: S-N inhibitors like thiourea and sewage sludge decomposition gases (SDG) are relatively novel dioxins suppressants and their efficiencies are proven in numerous lab-scale experiments. In this study, the suppression effects of both thiourea and SDG on the formation of dioxins are systematically tested in a pilot-scale system, situated at the bypass of a hazardous waste incinerator (HWI). Moreover, a flue gas recirculation system is used to get high dioxin suppression efficiencies. Operating experience shows that this system is capable of stable operation and to keep gaseous suppressant compounds at a high and desirable molar ratio (S + N)/Cl level in the flue gas. The suppression efficiencies of dioxins are investigated in flue gas both without and with addition of S-N inhibitors. A dioxin reduction of more than 80 % is already achieved when the (S + N)/Cl molar ratio is increased to ca. 2.20. When this (S + N)/Cl molar ratio has augmented to 4.18 by applying suppressant recirculation, the residual PCDD/Fs concentration in the flue gas shrank from 1.22 to 0.08 ng I-TEQ/Nm(3). Furthermore, the congener distribution of dioxins is analysed to find some possible explanation or suppression mechanism. In addition, a correlation analysis between (S + N)/Cl molar ratios and PCDD/Fs is also conducted to investigate the chief functional compounds for dioxin suppression.
authors.affiliation: State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, China.
authors.forename: Ming-Xiu
authors.initials: MX
authors.lastname: Zhan
authors.affiliation: China United Engineering Corporation, Hangzhou, 310052, People's Republic of China.
authors.forename: Jian-Ying
authors.initials: JY
authors.lastname: Fu
authors.affiliation: State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, China. chentong@cmee.zju.edu.cn.
authors.forename: Tong
authors.initials: T
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, China.
authors.forename: Xiao-Qing
authors.initials: XQ
authors.lastname: Lin
authors.affiliation: State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, China.
authors.forename: Xiao-Dong
authors.initials: XD
authors.lastname: Li
authors.affiliation: State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, China.
authors.forename: Jian-Hua
authors.initials: JH
authors.lastname: Yan
authors.affiliation: State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, China.
authors.forename: Alfons
authors.initials: A
authors.lastname: Buekens
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000517:prevention & control*; D001572:Benzofurans / Q000032:analysis; D004147:Dioxins / Q000032:analysis*; D005740:Gases / Q000032:analysis; D006256:Hazardous Waste / Q000032:analysis; D017745:Incineration / Q000379:methods*; D010865:Pilot Projects; D000072317:Polychlorinated Dibenzodioxins; D012722:Sewage
chemical_list: D000393:Air Pollutants; D001572:Benzofurans; D004147:Dioxins; D005740:Gases; D006256:Hazardous Waste; D000072317:Polychlorinated Dibenzodioxins; D012722:Sewage
keywords: Correlation analysis; PCDD/Fs; Pilot-scale experiment; S-N inhibitors; Suppression; Thiourea