Production and Destruction of Toxic Chemicals in Plastics Combustion

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Thermal decomposition of several kinds of resins, polyethylene, polypropylene, polystyrene, polyvinyl chloride, 6-nylon and alkyl-benzene sulphoic acid were investigated by using TG-DSC thermogravimeter in the atmosphere with and without oxygen. They show individual properties in endothermic or exothermic reaction, decomposition speed and auto-ignition characteristics. The product generated at 500, 650 and 800 deg.c were analyzed by GC/MS detector. Polyethylene produces much hydrocarbons at 500 and 650 deg.c, and much aromatic hydrocarbons at 800 deg.c. Chlorobenzenes and chrorophenols were analyzed for the decomposition products from polyvinyl chloride. The production of mono-chlorobenzenes and mono-chlorophenols are much more than the other congeners, so that chloro-benzenes and chloro-phenols are thought to be produced through the process of chlorine addition. The chlorination are promoted by the existence of oxygen. There were much amount of 2-mono-chlorophenol, 2,4-di- chlorophenol, 2,6-di-chlorophenol and 2,4,6-tri-chlorophenols in the decomposition products. The 2,4,6-positions are easily exchanged by chlorine. The flue gas and flyash from municipal refuse incineration plant were analyzed and the regression between the concentrations of chloro-benzenes and chloro-phenols and dioxins were investigated.