FEEDSTOCK EFFECTS, CATALYST PERFORMANCE AND PROCESS OPTIMIZATION IN WASTE PLASTIC-TO-FUEL PYROLYSIS: A REVIEW
The rapid accumulation of plastic waste and the growing demand for alternative energy sources have intensified interest in thermochemical conversion technologies capable of recovering value from end-of-life plastics. Among these technologies, thermal and catalytic pyrolysis have emerged as promising approaches for converting waste plastics into liquid fuels with properties comparable to conventional petroleum-derived fuels. This review examines recent advances (2019–2025) in waste plastic pyrolysis, with particular emphasis on the influence of feedstock characteristics, catalyst performance, and operating conditions on liquid fuel yield and quality. The review evaluates the pyrolytic behaviour of major plastic feedstocks, including polypropylene (PP), polyethylene (PE), polystyrene (PS), polyethylene terephthalate (PET), and mixed plastic wastes. Polyolefins and polystyrene consistently demonstrate superior liquid fuel yields, whereas PET and PVC present processing challenges due to the formation of oxygenated and chlorinated compounds. The role of catalysts, particularly zeolite-based materials such as ZSM-5 and HZSM-5, is assessed with respect to reaction temperature reduction, hydrocarbon selectivity, and fuel upgrading. The effects of key process parameters, including temperature, residence time, and reactor configuration, are also discussed. Findings indicate that catalytic pyrolysis generally achieves higher liquid yields, improved selectivity towards gasoline-range hydrocarbons, and lower energy requirements than thermal pyrolysis. Furthermore, the produced oils exhibit calorific values ranging from 41–49 MJ/kg and possess physicochemical properties that enable blending with conventional transportation fuels. Despite these advantages, challenges related to feedstock heterogeneity, catalyst deactivation, product upgrading, and economic viability continue to hinder large-scale deployment. The review highlights current trends and identifies opportunities for improving process efficiency and fuel quality, thereby supporting the development of sustainable waste plastic-to-fuel technologies within a circular economy framework.
Authors : Dumbulwa, S.S., Shuwa, M., Maina, M.B., Yahaya, I. and Abba, U.T.
Category : Open Access Volume (Issue) : 12(1) Date Uploaded : 5th August 2026