Experimental Study of Thermal and Catalytic Decomposition of PVC Wastes

Abstract

The excessive use of plastics in the last years is the challenge that has arisen in managing plastic wastes to avoid dangerous effects. Polyvinyl chloride is part of these wastes. It can be utilized to produce fuel-like petroleum fractions depending on pyrolysis, which is the thermal decomposition of plastics in the absence of oxygen. This work aims to reduce environmental pollution and reuse plastic waste as an alternative fuel source. A comparison of the thermal and catalytic processes under the optimum temperature 450 oC, pressure 20 bar, and residence time 1hour in a semi-batch reactor with and without adding Pt/Al2O3 and NiMo/Al2O3 catalysts. Thermo-gravimetric analysis (TGA) analysis was made for PVC. Catalysts were characterized by X-RAY diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). The liquid and gas products were analyzed by (GC/MS) to evaluate the quality of products. In the hydro-cracking reaction, most gas products were produced using NiMo/Al2O3 catalyst, about 62.29 wt%. The aromatic and saturated-aliphatic in the liquid using NiMo/Al2O3 catalysts were 21.07 and 72.81 wt%. The aromatics and saturated aliphatic in the liquid product using thermal non-catalytic and Pt/Al2O3 catalysts were 23.83 wt% & 63.52 wt% and 21.88 wt% & 64.01, respectively. The ratio of gasoline range components is the highest in the hydrocracking process on NiMo/Al2O3 catalysts. Using catalytic-hydrocracking on Pt/Al2O3 gives the highest diesel range component. It was confirmed that the generated undesirable product seems was very few in the hydrocracking reactions compared to the thermal cracking reactions.