Pyro-gas analysis of fixed bed reactor end of life tyres (ELTs) pyrolysis: A comparative study

Pyrolysis of end of life tyres (ELTs) present a promising alternative to their incineration or classical product recovery using mechanical means. It can produce light hydrocarbons (HCs) and other valuable chemicals as part of the pyro-gas stream it generates. In this work, two grades of tyres namely a fresh (virgin) one and a waste disposed ELTs, were used as a feedstock to analyse their pyro-gas constituents. There wasn't much difference in the maximum conversion rate between both tyre grades where the fresh tyres had an estimated 15.17% conversion and the ELTs was 13.45% conversion (both at 800 °C). The difference herein was attributed to release of free radicals prior to subjecting the samples to pyrolysis due to their history. The analysis of the pyro-gas samples showed a large make of light hydrocarbon (HC) products, namely methane (CH₄/C₁), ethane (C₂H₆/C₂), ethylene (C₂H₄), propane (C₃H₈/C₃), propylene (C₃H₆), n-butane (C₄H₁₀), butadiene compounds, carbon mono and dioxide (CO,CO₂). Light HCs mimciking natural gas were more abundant in the case of ELTs were C₁ was estimated as 14.53% at 500 °C and 16.73% at 800 °C. C₂ was also estimated higher than the fresh tyres where a 11.78% at 500 °C was noted and 7.67% at 800 °C. It can be recommended that future integration plans in oil and gas ventures, namely refinery and petrochemical complexes, are to start taking responsible measures towards the environment by substituting part of their operations with sustainable feedstock such as ELTs.