Chlorinated aromatics from combustion: influence of chlorine, combustion conditions, and catalytic activity.
Research on the formation of chlorinated aromatics in combustion processes has mainly taken place in the laboratory. Previous attempts to correlate observation data from commercial plants have been inconclusive. This study reports on the outcome of an industrial experiment in a full-scale afterburner. The influence of chlorine input, combustion temperature, and catalytic activity was investigated in a factorial design with two blocks. Polychlorinated benzenes, dibenzo-p-dioxins, and dibenzofurans were formed both at combustion temperatures and below 400 degrees C. The results show that all three experimental factors have statistically significant impact on the formation and release of these toxic byproducts. The quantitative dependence between chlorine input and the occurrence of chlorinated aromatics is of particular interest due to previous controversy. The purpose with this study was to ensure that the installation of a boiler for energy recovery would not cause elevated emissions of chlorinated aromatics. The experiment demonstrated that this risk is probably low, since the presence of catalytic material or an increase in chlorine input is required for this to happen. A general conclusion was that industrial experimentation employing the principles of statistical design could improve the validity in recommendations regarding commercial plant operation.
Oberg
T
T
Department of Biology and Environmental Science, University of Kalmar, SE-391 82 Kalmar, Sweden. tomas.oberg@hik.se
Ohrström
T
T
D000393:Air Pollutants / Q000032:analysis*; D002384:Catalysis; D017606:Chlorine Compounds / Q000032:analysis*; D006841:Hydrocarbons, Aromatic / Q000032:analysis*; D017745:Incineration; D007220:Industrial Waste; D012037:Refuse Disposal
D000393:Air Pollutants; D017606:Chlorine Compounds; D006841:Hydrocarbons, Aromatic; D007220:Industrial Waste