Catalytic Effect of Fly Ash on Potential Formation and Destruction for PBDD/Fs in the Air Pollution Control Devices
The formation and release of polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs), from thermal treatment of e-wastes that contain brominated flame retardants (BFRs), have received considerable attention. Fly ash and stack flue gas from these e-wastes incinerators have been documented to contain elevated concentrations of PBDD/Fs. Mixed brominated/chlorinated dibenzo-p-dioxins have mainly been reported for sites in the immediate vicinity of anthropogenic combustion. Experiments were conducted adding the inorganic chloride or bromide sources with bag house fly ashes in a packed bed reactor under real flue gas conditions to simulate the filter cake zone. Our studies indicated that the halogenated dioxin yields between the fly ash residue phase and the downstream flue gas was significantly changed under the catalytic effects of precursors. The results showed that the chlorine source had obviously changed the PCDD/Fs distribution in the residue phase. Furthermore, the PBDD/Fs fraction was 16.23% and 9.16% in the residue phase, was 83.77% and 90.84% in the gas phase, respectively. It showed that the main formation of PBDD/Fs happen in the gas phase. On fraction of PCDD/Fs and PBDD/Fs congener profiles, the OCDD was predominant of PCDD/Fs in the residue phase, followed by 1,2,3,4,6,7,8-HpCDD. However, the OBDF was predominant of PBDD/Fs in the residue phase, followed by 1,2,3,4,6,7,8-HpBDF. In the downstream of flue gas, the PCDD/Fs and PBDD/Fs congeners were still these four dominant species. The results of the study indicated that adding chlorine source into the fly ash has significantly enhancement for the PCDD/Fs in the residue phase, but adding bromine source had significantly enhancement for the PBDD/Fs formation in the gas phase. The above results suggested that the filter cake ash treatment should be studied extensively to control halogenated dioxin yields on the fly ash matrix.
Chieh LIN Tu-Po CHUNG Yu-Te CHIN Chih-Yeh CHAO
Dept.of Environmental Engineering and Science, National Pingtung University of Science and Technolog Dept.of Mechanical Engineering, National Pingtung University of Science and Technology, Pingtung, Ta
国际会议
The Fifth International Conference on Waste Management and Technology(第五届固体废物管理与技术国际会议)
北京
英文
514-517
2010-11-01（万方平台首次上网日期，不代表论文的发表时间）