Critical issues for the deployment of plastic waste pyrolysis

Despite the urgent need to valorize plastic waste, stopping its uncontrolled release into the environment, and the increased 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 heterogeneous catalysts for 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 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 plastic pyrolysis processes as an essential tool for the design of large scale plants.