Investigation of the effect of alumina porous media on the polyethylene waste pyrolysis with continuous feed

Abstract

This study investigates the pyrolysis of polyethylene waste in a continuous-feed mode to provide novel insights into recycling waste plastics. Alumina (Al2O3) porous media has been introduced into the pyrolysis reactor to study its effect on continuous-feeding plastic waste pyrolysis. The pyrolysis product yields, oil fractions, and gas components have been determined under varying porous media structures, i.e., thickness and pore size, and operating parameters, i.e., temperature and gas-carrying velocity. To the best of our knowledge, it is the first attempt to investigate the influence of porous media pore size on the thermal decomposition of waste polyolefin in continuous feeding mode. The results reveal that higher thicknesses and smaller pore sizes of porous media can enhance the properties of pyrolysis oil with lower heavy fractions (>C20). The aromatization of light olefins is triggered when the temperature exceeds 520 °C, resulting in a rapid increase in light fraction (<C12) in pyrolysis oil. Moreover, the gas-carrying velocity determines the pyrolysis product distribution by regulating the volatiles' residence time.