Pyrolysis of rubber tyre wastes: A kinetic study

The purpose of the present study was the analysis of possible routes for the pyrolysis reaction mechanism of rubber tyre wastes (RT). For this purpose, an evaluation was performed integrating both experimental data and different kinetic models. As none of the mechanisms found in literature allowed the numerical adjustment to the experimental data, new pathways were tested. Rubber tyre wastes kinetic studies were performed in order to evaluate possible direct conversions into new products (solids, liquids and gaseous), parallel reactions and/or reversible elementary steps. All experiments were carried out in a micro-autoclave system and based on the results obtained, at different temperatures and reactions times, kinetics models were evaluated and reactions pathways were established. Furthermore, products composition were analysed and according to the experimental data different reaction mechanisms were proposed. Afterwards, the kinetic data was compared with the experimental data. The proposed models were found to fit with the experimental data, which has allowed several explanations for the thermal degradation of rubber tyre waste to be proposed. Kinetics parameters were estimated, the dependence of activation energy and pre-exponential factor on temperature were evaluated. It was found that the rate constant of a number of reactions exhibited nonlinear temperature dependence on the logarithmic form of Arrhenius law, which strongly suggest that reaction temperature has an effect on reaction mechanism of rubber tyre wastes pyrolysis. (C) 2012 Elsevier Ltd. All rights reserved.