Assessment of the Efficiency of Catalysts for the Catalytic Pyrolysis of Polyethylene

Abstract

The study is focused on the catalytic pyrolysis of high density polyethylene (PE) in the presence of HBEA, HZSM-5, and HFER catalysts and natural clay. The catalytic pyrolysis of plastics is a promising method to process recyclable materials, because it provides the conversion of polymers to other compounds, which are subsequently used as reagents for the chemical industry. The physicochemical parameters of the catalysts have been determined by Fourier transform IR spectroscopy, X-ray diffraction analysis, the nitrogen physical adsorption method, thermogravimetric analysis, and pyrolytic gas chromatography. The dependences of the PE degradation temperatures and the chemical composition of the catalytic pyrolysis products on the type of catalyst used have been revealed. The efficiency of the cracking process and the qualitative composition of the products are affected by two main factors: the structural and acidic parameters of the catalyst. The presence of Brønsted acid sites in zeolites contributes to the occurrence of the cracking and aromatization reactions. The possibility of using a clay sample for the thermal degradation of PE has been studied.