Energy Recovery from Tyre Waste Pyrolysis: Product Yield Analysis and Characterization

Yearly, out of 1 billion tyres, 40% are heavy-load vehicle tyre which was rejected or discarded to the dump sites where it piles up due to its non-degradable nature creating a problem for disposal. With the same rate of production, the problem is increasing day by day forcing the researchers to find alternatives for the disposal as well as energy recovery as these are a good source of carbon fuel. Methods such as open burning are not favoured because of high pollutant emission into the environment. Pyrolysis has emerged out as the best-suited option for the disposal as well as energy recovery. In this study, TG analysis was performed to determine the effect of temperature on the degradation of tyre waste in an inert atmosphere. Further, based on the analysis, heavy-vehicle tyres were pyrolysed in a temperature range of 550–800 °C for the recovery of valuable products such as pyrolytic as fuel oil, non-condensable gases as fuel gas and residue char as the carbon source. The pyrolysis process produces oil yield between 50 and 60% with a char yield of 32–38%, and the remaining were gases. The oil had a high calorific value of 34.743 kJ/Kg, whereas the evolved gas contains a heating value of 54.553 kJ/Kg. The gases obtained were analysed using gas chromatography showing a high percentage of hydrogen and C₁–C₄ hydrocarbon gases. The obtained char was analysed via SEM-EDX which confirms the presence of sulphur in high percentage. Also, the remaining char was activated using steam at 800 and 900 °C to increase the surface area for utilization as an activated carbon source and was determined by BET analysis.