Pyrolysis for plastic waste management: An engineering perspective

Abstract

The pervasion of plastic and the inadequacies of the current plastic waste management processes are the premise of various studies that aimed to find sustainable solutions to the plastic waste issues. Amongst these solutions, plastic pyrolysis is particularly promising due to its commercial maturity and complementarity to mechanical recycling. In this paper, recent studies of plastic pyrolysis are reviewed and scrutinised, with particular attention given to feedstock composition, operating conditions, and catalytic choices. Our systematic review found that the success of plastic pyrolysis is dependent on many inter-related operational factors, such as temperature, residence time, and feedstock characteristics. Thus, the application of Artificial Intelligence (AI) can enhance our understanding of the various interconnected parameters involved in plastic pyrolysis. However, AI capacity must be further improved to incorporate more variables such as contaminants, fluctuating feedstocks, and mixed polymers. Many Life Cycle Assessments (LCA) studies have provided abundant evidence showing that plastic pyrolysis is more environmentally beneficial incineration and landfill. Hence, future LCA studies should shift from a comparative perspective to a more holistic approach where plastic pyrolysis is considered as an integrated part of a sustainable waste management system. The review has also identified that more research efforts should be directed towards catalytic pyrolysis and monomer recovery.