The influence of zeolite catalyst on kinetics and thermodynamics of polypropylene waste thermal degradation

Abstract

Thermal conversion characteristics of polypropylene waste mixed with various amounts of regenerated fluid catalytic cracking catalyst (FCCC) were quantitatively identified, and the dependences of these parameters on the FCCC amount used were determined. The three methods (standard ASTM 1641, improved methods of Ozawa–Flynn–Wall, and Kissinger–Akahira–Sunose) were used in kinetic parameters estimation. The thermodynamic parameters were estimated by Eyring equation. At the beginning of polypropylene waste decomposition reactions, the kinetic and thermodynamic parameters show tendency to decrease with the increasing FCCC amount in the mixture. The aforementioned tendency at every conversion during a whole reaction is valid only for the free Gibbs energy which value practically does not change very significantly during the reaction. The change of estimated parameters shows a clear tendency at every conversion only when the FCCC amount in the mixture is high enough. The reaction orders increase with increasing FCCC amount in the beginning of the reactions and they vary with the conversion. The relative thermal stability estimated also depends on the quantitative composition of the mixtures.