The evaluation of dioxin emissions from pilot scale incineration of organochlorine compounds.

Formation of the dioxins was investigated in case of two fuel types (kerosene-dichlorobenzene and kerosene-dichloroethane) on a pilot scale liquid waste incinerator. It was determined the effect of the molecule structure (aromatic, aliphatic) and Cl content (1, 3 and 6%) of the liquids and the combustion parameters (O2 content, residence time and temperature). In some experiments particulate matters (fly ash and soot) were injected. The measured dioxin concentrations ranged up to 160 ng/Nm3 or till 10 ng/Nm3 TEQ, except at addition of soot where extremely high dioxin concentrations (up to 750 ng/Nm3, or 30 ng/Nm3 TEQ) were measured. Main conclusions of the experiment are: The incineration of aromatic chlorinated products produce almost 10 times higher dioxin concentrations than the aliphatic ones. A relatively low dioxin concentration is caused at low (1 to 3%) feed Cl contents while over a threshold value of more than 3% Cl intensifies sharply the dioxin formation. The dioxin generation can be characterized with concentrations measured at 600-650 degrees C. Dioxin toxicity reduction occurs when cooling down to 200-250 degrees C. Changes between these sampling temperatures can be explained mostly by sorption phenomena occurring between dioxin content of flue gases and solid deposits.