SULFUR-POLYCYCLIC AROMATIC-HYDROCARBONS IN TYRE PYROLYSIS OIL

Scrap tyres were pyrolysed in two bench-scale reactors: a static batch slow pyrolysis reactor and a fluidized bed reactor. The pyrolysis oils were analysed for their content of sulfur-polycyclic aromatic hydrocarbons (PASH), using a series of liquid column chromatography fractionations with oxidation and reduction to produce a PASH-enriched sample. The PASH were identified and quantified using coupled capillary column gas chromatography-mass spectrometry and capillary column gas chromatography with flame photometric sulfur-selective detection. The PASH identified were mainly dibenzothiophene and methyl, dimethyl and trimethyl dibenzothiophenes, and also naphthothiophenes and their methyl derivatives. The PASH identified were not biologically active according to the literature on the mutagenicity and carcinogenicity of PASH. Increasing temperature of pyrolysis increased the concentration of PASH in the pyrolysis oils; this was attributed to a Diels-Alder type aromatization reaction.