Chemical Feedstock Recovery through Plastic Pyrolysis: Challenges and Perspectives toward a Circular Economy.

Abstract

Plastics are indispensable in daily life, with both production and waste generation increasing annually. As the world strives for net-zero emissions, advancing plastic recycling technologies has become a global priority. Pyrolytic liquefaction is a promising approach for recovering chemical feedstocks, including fuel fractions, from waste plastics, potentially substituting petroleum resources. Since the 1970s, research on pyrolytic liquefaction has progressed globally, and several industrial-scale plants are now in operation. However, to accelerate the transition to a circular economy, it is crucial to bridge the knowledge gap between lab-scale research and industrial-scale implementation of pyrolysis-liquefaction technologies. This review provides a comprehensive analysis of the current state of plastic recycling, the progress and challenges in cutting-edge lab-scale research on pyrolytic liquefaction, alongside the latest trends in industrial-scale liquefaction projects. It reveals that pyrolytic liquefaction of a wide range of plastics-including halogenated plastics and poly(ethylene terephthalate)-has been extensively studied at the laboratory level. In contrast, industrial-scale operations often focus on more common, easily pyrolyzed plastics and generally avoid the use of catalysts. This highlights the urgent need to develop robust, reusable, and cost-effective catalysts, as well as optimized process designs, to expand the range of plastic feedstocks suitable for industrial-scale pyrolysis plants.