Dynamic pyrolysis characteristics, kinetics and products analysis of waste tire catalytic pyrolysis with Ni/Fe-ZSM-5 catalysts using TG-IR-GC/MS

Abstract

Catalysts are usually used in the thermal conversion of waste tires to enhance the efficiency of the process and the quality of pyrolytic products. Recently, it has already been proved that Ni/Fe bimetallic catalysts had an effective catalytic effect on the thermal decomposition of organic solid wastes. Herein, we employed a TG-IR-GC/MS system to investigate the kinetics and product analysis of waste tire catalytic pyrolysis using Ni/Fe bimetallic ZSM-5 as catalysts. Iso-conversional methods and master-plot methods were employed to estimate the activation energies and reaction model of waste tire catalytic pyrolysis. The results illustrated that the ZSM-5 loading with 7 wt.% Ni and 3 wt.% Fe had the best catalytic effect on decreasing the activation energies with a reduction of 13%. The determination of kinetic models showed that both non-catalyzed and catalyzed pyrolysis were fitted to a Fn model while the addition of a catalyst reduced the reaction order to varying degrees. Both FTIR and GC/MS results suggested that the metallic Ni-based catalyst had strong ability to transform alkenes into aromatic hydrocarbons. Ni/Fe bimetallic catalysts showed almost the same catalytic performance as the Ni metallic catalyst, which could reduce the cost of the catalyst. Thus, this study could deepen the understanding and provide a basic guideline of Ni/Fe bimetallic catalysts on the catalytic pyrolysis process of waste tires.