Characterization of the liquid products obtained in tyre pyrolysis

Cross-section samples (2-3 cm wide), representative of a whole car tyre, have been pyrolysed under nitrogen in a 3.5 dm(3) autoclave at 300, 400, 500, 600 and 700 degreesC. Over 500 degreesC there is no effect of temperature on gases and liquids yields (approximate to17 and 38%, respectively). Tyre pyrolysis liquids have been characterized, including elemental analysis, gross calorific value (GCV), gas chromatography/mass spectroscopy (GUMS) and distillation. Tyre derived liquids are a complex mixture of C-6-C-24 organic compounds, with a lot of aromatics (53.4-74.8%), some nitrogenated (2.47-3.5%) and some oxygenated compounds (2.29-4.85%). They have GCV (42 MJ kg(-1)) even higher than those specified for commercial heating oils, but sulphur contents (1-1.4%) near or slightly over the law limit value. Significant quantities of valuable light hydrocarbons such as benzene, toluene, xylene, limonene, etc. were obtained. The concentration of these compounds increase with temperature up to 500 degreesC and then decrease. There are an important proportion of polycyclic aromatics such as naphthalenes, phenanthrenes, fluorenes, diphenlys, etc.; their concentration as well as that of total aromatics increases significantly with temperature. Distillation data of the 500 degreesC oils showed that approximate to20% have the boiling range of light naphtha (<160 degreesC), approximate to10% of heavy naphtha (160-204 degreesC) and; approximate to35% of middle distillate (204-350 degreesC). As far as distillation data are concerned, the tyre oil fractions with the same boiling range as commercial automotive diesel oils and heating diesel oils fulfil the present specifications of such commercial products. (C) 2004 Elsevier B.V All rights reserved.