Experimental proof of concept for a sustainable End of Life Tyres pyrolysis with energy and porous materials production

Abstract

The present work addresses the importance of pyrolysis to manage waste tyres from a cleaner production and circular economy approach. Optimisation of End of Life Tyres (ELT) pyrolysis conditions, targeting to high added value products, requires further investigation, extensive products characterisation and standardisation. The experimental investigation and technical assessment of ELT pyrolysis in a batch rotary kiln reactor is addressed in the current study. Temperature, heating rate and particle size effects on product yields were studied. Yields and properties of the pyrolytic products are pointed out, with special attention given to the liquid fraction (properties as alternative fuel) and to solid fraction (highlighting its properties as activated carbon precursor). At pyrolysis temperature of 550 °C, heating rate of 20 °C/min and atmospheric pressure, tyre shredders of 15–20 mm particle size gave a maximum liquid yield of 51.8 wt%, while gas and char reached 12.1 wt% and 35.5 wt% respectively. The gaseous and liquid fractions obtained, exhibited high calorific values of 23.8 MJ/m3 and 40.8 MJ/kg, respectively. Activation of solid fraction (char) with KOH (weight ratio 4:1) resulted in the production of a porous material exhibiting a N2 BET surface area of 402 m2/g.