A SYSTEMATIC REVIEW OF PYROLYSIS BASED LIQUID FUEL CONVERSION FROM PLASTIC WASTE

The escalating accumulation of plastic waste poses a pressing environmental and resource challenge, prompting the need for sustainable conversion technologies. Pyrolysis has emerged as a promising thermochemical route for transforming waste plastics into liquid fuels with potential to partially replace conventional fossil-derived fuels. However, progress in this domain remains fragmented, necessitating a comprehensive synthesis of recent advancements. This study presents a systematic literature review (SLR) on pyrolysis-based liquid fuel production from plastic waste, adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. Relevant studies were retrieved from two major databases—Web of Science and Scopus—using carefully constructed search strings, resulting in 26 primary studies meeting the inclusion criteria. The findings were synthesized into three thematic domains: (1) Catalyst Development and Catalytic Mechanisms in Pyrolysis, which highlights advances in catalyst formulation, active site engineering, and reaction pathway elucidation for enhanced product selectivity; (2) Process Optimization, Kinetics, and Mechanistic Studies, focusing on the impact of operating parameters, reactor configurations, and kinetic modelling on maximizing liquid fuel yields and process efficiency; and (3) Fuel Production, Engine Application, and Environmental Assessment, which evaluates fuel quality upgrades, engine performance compatibility, and potential environmental benefits in reducing waste volumes and greenhouse gas emissions. The analysis reveals that catalytic pyrolysis consistently delivers higher-quality liquid fuels, with several studies reporting yield improvements exceeding 20% over non-catalytic processes. Process parameter tuning and kinetic insights further contribute to efficiency gains and targeted hydrocarbon profiles. In conclusion, pyrolysis offers significant potential for sustainable plastic waste valorization, but future research should emphasize integrative approaches linking catalyst innovation, process optimization, and real-world application to achieve scalable, economically viable, and environmentally responsible solutions.