De Novo Formation of Polychlorinated Dibenzo-p-Dioxins and Polychlorinated Dibenzofurans during the Gas Cooling Process in a Solid Waste Incinerator

De Novo Formation of Polychlorinated Dibenzo-p-Dioxins and Polychlorinated Dibenzofurans during the Gas Cooling Process in a Solid Waste Incinerator

Noriaki Ishibashi*, Shigenobu Okajima*, Yoshinobu Yoshihara**, Kazuie Nishiwaki** and Masakatsu Hiraoka*
* Research Center for Eco-Technology, Ritsumeikan University
** Department of Mechanical Engineering, Faculty of Engineering, Ritsumeikan University
+ Correspondence should be addressed to Noriaki Ishibashi:
Research Center for Eco-Technology, Ritsumeikan University
(1-1-1 Noji-higashi, Kusatsu-city, Shiga, 525-8577 Japan)

Abstract
The de novo formation of polychlorinated dibenzo-p-dioxins(PCDDs)and polychlorinated dibenzofurans(PCDFs)caused by the interaction between fly ash and flue gas was investigated. In these experiments, flue gas from the laboratory-scale fluidized-bed incinerator was passed through an electrically heated flow reactor in which fly ash obtained at the same laboratory-scale incinerator has been filled. The results show that PCDD/Fs formed in where large amount of fly ash has been deposited by the internal force and thermo-phoresis. In the case of the de novo formation, PCDDs/DFs concentration is proportional to the HCl concentration in the flue gas. It is also noted that PCDDs/DFs are not formed at the temperatures around 200C[Celsius degree] but significant PCDDs/DFs formation was observed at around 300C[Celsius degree] and also that Cu content in the fly ash at the level of 10wt% strongly promote PCDDs/DFs formation at not only 300C[Celsius degree] but also 200C[Celsius degree].

Key words: polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, solid waste incinerator, de novo formation, chlorine