Conversion of End-of-Life Vehicle Tyres as a chemical Feedstock for the Production of Diesel Range Liquid Fuel and Char

Abstract

Globally, over 780 billion plastics are used and discarded annually, with no proven avenues for value recovery from this category of the waste stream. This research work investigated the potential for generating diesel range liquid fuel from end-of-life vehicle tyres (EVTs) using a charred palm kernel shell fired reactor-blower assembly in the temperature range of 300 °C – 660 °C. Samples of EVTs were collected from Tarkwa Municipality in the Western Region of Ghana and were shredded and dried in the open. Samples of the shredded EVTs weighing approximately 2.0 kg were fed from the top of a stainless steel reactor and pyrolysed for 55 minutes at a heating rate of 40 °C/min. The gas leaving the reactor was then condensed in a plastic container, weighed and characterised by FT-IR and GC-MS analysis. The results indicate that samples of diesel range liquid fuel (density 0.936 g/cm3) can be produced from EVTs with a yield in the range of 0.33 - 0.40 litres/kg of pyrolysed material. Results from FT-IR and GC-MS analyses showed that the liquid fuel consists primarily of aromatic hydrocarbons (alkyl benzenes), aliphatic hydrocarbons and minor amounts of naphthenes. SEM-EDS analysis of the solid by-product revealed partly carbonaceous material (67.18 ~ 86.67 wt. % C) that could burn to yield an ash rich in CaO, ZnO and TiO2. It was concluded that liquid fuel production by pyrolysis could offer a benign route for the sustainable disposal of end-of-life vehicle tyres and other hazardous polymer wastes.