The effect of pre-pyrolysis chemical treatment of waste tyre rubber crumbs : comparison between pre-treated and conventional waste tyre-derived oil

Abstract

BACKGROUND : Pyrolysis process is one of the most effective recycling methods due to its ability to recover products like gas, oil and char with oil being the major/important product. The shortcomings of waste tyre-derived oil from the conventional pyrolysis process are that the oil contains high amounts of sulfur and polycyclic aromatic hydrocarbons (PAHs) and has a pungent smell, which makes it difficult to utilize further. The aim of this study is to investigate the effect of chemical pre-treated waste tyre rubber crumb-derived oil versus conventional waste tyre oil. The instrumentation utilized in this study was to solely investigate the shortcomings of waste tyre pyrolysis (high sulfur and PAH content and also high temperature required for waste tyre pyrolysis). RESULTS : The results showed a reduction in amounts of both sulfur and PAHs in treated waste tyre-derived oil by about 83% and 77% respectively. Also, there was a reduction in initial pyrolysis temperature for the treated waste tyre crumb as compared to untreated waste tyre crumb: a temperature range of 96–115 °C for treated waste tyre crumbs as compared to 300–400 °C for untreated waste tyre crumbs. CONCLUSIONS : The success of this study means the production of quality oil at a low temperature with lower amounts of PAHs and sulfur and less odour, plus the possibilities of it being used as a petroleum fuel or for extraction of important compounds like benzene, toluene, xylene, limonene and C12–C20 acids.