Interaction of three categories of tyre waste during co-pyrolysis: Effect on product yield and quality

摘要

Disposal of huge generation of non-biodegradable waste tyre poses a big environmental threat today. Energy recovery through thermo-chemical route like pyrolysis has been emerging as an important research area. Though pyrolysis of individual tyre waste was investigated by various researchers, the impact of the interaction of different type of tyres in the waste mix on the pyrolysis process, product yield and properties needs further research. This work was taken up to bridge this gap. In this work, a mix of three different tyre waste; namely light vehicle tyre (LVT), medium vehicle tyre (MVT) and heavy vehicle tyre (HVT), was pyrolysed at 750 degrees C with varying proportions to assess the synergistic effect on the products yield and their characteristics. Higher fraction of LVT in the mix reduced the degradation temperature of the mixed tyre due to the dominant presence of natural rubber (NR). Higher fraction of HVT increased the degradation temperature due to greater presence of BR. Also, a higher amount styrene in the mix caused larger fractional residue. MVT produced the highest char yield as it had highest ash content and more styrene butadiene rubber (SBR) and lowest oil yield due to very less presence of NR and butadiene rubber (BR). HVT produced the lowest char and highest oil yields due to the presence of NR and BR and low ash. The experimental results showed a higher solid (char) yield than that predicted. The gas yield was less than that predicted. The oil yield, however, showed a much lower synergistic effect. At degradation 50%, the gas primarily consisted of hydrogen and methane while other gases such as C-2-C-6, CO and CO2 were present in small quantities. The oil fractions obtained from the pyrolysis of waste tyre showed a strong similarity with the gasoline range hydrocarbons. Produced char with a high surface area may be activated further and used as activated carbon in waste water treatment.