Fast pyrolysis kinetics of waste tires and its products studied by a wireless-powered thermo-balance.

Abstract

Fast pyrolysis is commonly used in industrial reactors to convert waste tires into fine chemicals and fuels. However, current thermogravimetric analyzers are facing limitations that prevent the acquisition of kinetic information. To better understand the reaction kinetics, we designed a novel thermo-balance device that was capable of in-situ weight measurement during rapid heating. The results showed that the reaction rate substantially increased, with significant reductions in reaction time and apparent activation energy compared to slow pyrolysis. The change of reaction mechanism from the reaction order model to the nucleation and growth model was responsible for the increase in the degradation rate. Fast pyrolysis led to the generation of more trimers of isoprene as primary pyrolytic volatiles, which we further supported through density functional theory calculations. The findings suggested that fast pyrolysis has a higher chance of overcoming the high energy barrier to form trimers of isoprene. This comprehensive and in-depth understanding of fast pyrolysis kinetics and product distribution could reveal a more realistic process of waste pyrolysis, which benefited the industry.