Valorisation of End of Life Tyres (ELTs) in a Newly Developed Pyrolysis Fixed-Bed Batch Process

Abstract

This article shows a preliminary study of an end of life tyres (ELTs) use as a feedstock in a newly developed and patented reactor system that utilises a three zone heating element set-up along its fixed bed. The pyrolysis reaction was conducted between 500 to 700 °C and has yielded a maximum pyrolysis oil at 500 °C which was attributed to the promotion of secondary cracking of the oil into permanent (non-condensable) gaseous products. The oil yield and properties including estimated mass balance, sulphur content and higher heating value (HHV) shows that the pyro-oil is within fuel standards of the market making it a green and renewable resource off of waste. In addition, The hydrocarbon (HC) range of the products obtained from the oil shows that it is within the diesel range of typical fuels. The analysis of the gaseous products from the pyrolysis showed that an increase in the average reactor bed temperature promotes the decomposition of primary HC and pyrolysis oil into secondary products. This results in the detection of tetradecanoic acid, limonene and eicosane, among other major chemical groups at temperatures above 550 °C which is the end-set temperature of feedstock examined. It can be concluded that by using such a reactor set-up and upgrading the fuels extracted from its downstream stigmatic features of fixed bed reactors might be overcome with a lucrative economical value and rate of return in a circular economy perspective.