抄録
In the combustion processes such as a municipal and an industrial waste incinerations, O2 concentration in a combustion gas is considered to be one of the important parameters against formation and/or suppression of toxic dioxins/furans (hereinafter referred to as dioxins), but there are a few papers which discuss the relationship between dioxins concentration and O2 concentration in a combustion gas. In the present study, the influence of the residual O2 concentration in an exhaust gas on the concentration of dioxins formation has been investigated by combustion experiments at 1073 K with polyvinyl chloride (PVC) powder. The residual O2 concentration in the exhaust gas has been changed widely from 0.1 to 35 vol% by varying the mixture ratio of O2-N2 gas compositions and/or the PVC feed rate. Dioxins concentration has the maximum value at the residual O2 concentration in the exhaust gas of about 3 vol%, and their concentration sharply decreases in proportion to the rise in the residual O2 concentration, but the decrease in dioxins concentration becomes very slow in the residual O2 concentration more than 10 vol%. On the other hand, dioxins concentration decreases under the high reducing atmosphere with the residual O2 concentration of 0.1 vol% and CO concentration of 2.5 vol%.
