Critical issues for the deployment of plastic waste pyrolysis

Abstract

Despite the urgent need to valorize plastic waste, subtracting them from uncontrolled release into the environment, and the availability of consolidated thermal and catalytic technologies, the large-scale deployment of pyrolysis as a reference technology for the efficient processing of plastic waste still faces significant challenges. Accordingly, this review is focused on a number of issues that are essential for the industrial development of plastic waste pyrolysis technologies: i) the use of heterogenous catalysts for a better control of the product properties and the softening of the operation conditions, analyzing the important limitations derived from catalyst deactivation, ii) the different types of treatments investigated for the safe removal of halogens, which are often present in the pyrolysis oils in the form of Cl- and Br-containing organic compounds, thus avoiding health and environmental problems and the corrosion of equipment, iii) the co-processing of plastic waste with other feedstocks (biomass, petroleum fractions, used tires, etc.), which may result in significant synergistic effects, and iv) the multi-scale modelling of plastics pyrolysis processes as an essential tool for the design of large scale plants.