Kinetics and thermodynamics investigation of pyrolysis of butyl rubber tube waste

Abstract

Pyrolysis of butyl rubber tube waste was performed under an inert nitrogen gas environment for temperature ranging between 25 and 1,000 °C, by varying the heating rates (5, 10, 20, 35, and 55 °C min<sup>−1</sup>). Five different iso-conversional approaches, namely, Differential Friedman, Ozawa-Flynn-Wall, Kissinger-Akahira-Sunuse, Distributed activation, and Starink, were employed to investigate the kinetics and thermodynamic parameters. The mean activation energy (<i>E</i><i><sub>α</sub></i>), and pre-exponential factor (<i>k<sub>o</sub></i>) varied between 222.67 and 244.73 kJ mol<sup>-1</sup> and 6.82×10<sup>21</sup> and 2.73×10<sup>24</sup> s<sup>-1 </sup>respectively, for all iso-conversional approaches. From the kinetic investigation, a strong correlation co-efficient (R<sup>2</sup>>0.97) was ascertained in the conversion range of up to α=0.8 for all the iso-conversational approaches. By thermodynamic analysis, the mean values of change in enthalpy and change in Gibbs free energy were 217.06-239.13 kJ mol<sup>-1 </sup>and 185.12-218.11, kJ mol<sup>-1</sup>, respectively. From the master plot analysis, diffusion model (D3), and several reaction order models (F1, F2, F3, and F5) were predicted throughout the conversion (0.1 to 0.8) limit at 20 °C min<sup>-1</sup> for the pyrolysis of BRT.