Slow pyrolysis of end of life tyres (ELTs) grades: Effect of temperature on pyro-oil yield and quality

Abstract

This study presents the thermo-chemical conversion by means of pyrolysis as a route to valorise end of life tyres (ELTs) in a sustainable manner whilst targeting produced pyrolysis oil (pyro-oil) to replace conventional fossil fuels. The work presented here compares the results of pyro-oil extracted from the pyrolysis of three tyre grades, namely fresh (new) tyres, car and lorry truck ELTs; and investigates the pyro-oil extracted for fuel properties and common fuel hydrocarbon range. A fixed bed reactor system was used to conduct the experimental runs between 500 and 800 °C. The results show that fresh tyres and car ELTs yield some 45% of pyro-oil at an average reactor bed temperature equal to 600 °C which promotes evolution of liquid hydrocarbons via primary route of tyres cracking, hence pyro-oil production to a maximum. Furthermore, and at a similar operating temperature; the diesel range hydrocarbons (C10–C19) were around 66% of the total fuel like chromatograph studied for the pyrolysis oils. The work in this study and based on properties of fuel investigated point towards blending the oil extracted with conventional fuels that could result in lowering dependency on fossil based ones. Further upgrading is also possible whereby desulphurisation could lead to renewable and sustainable fuel source utilising a solid waste feedstock such as ELTs.