Catalytic conversion of biomass and plastic waste to alternative aviation fuels: A review

The depletion of fossil fuel sources and the urgency to combat global warming have led to extensive research into renewable energy alternatives. Among these alternatives, biofuel is emerging as a promising replacement for petroleum fuel. The aviation industry, which produces significant CO2 emissions annually, recognizes the need for sustainable solutions to minimize its carbon footprint. Biomass-to-liquid thermochemical routes, a cornerstone in sustainable hydrocarbon fuel production, are particularly pivotal for bio-jet fuel synthesis. Among the diverse thermal conversion technologies, pyrolysis holds promise for transforming waste biomass and plastic into liquid fuels. However, the ensuing oil from renewable biological sources and/or waste plastics from pyrolysis poses significant challenges due to its inferior quality, characterized by oxygenated compounds and high water content. The resulting oil from renewable biological sources and/or waste plastics is chemically unstable, viscous, and corrosive, necessitating thorough upgrading for its viable use as a kerosene fraction or blend. This review focuses on catalytic post-treatment strategies for enhancing oil from renewable biological sources and/or waste plastics quality, specifically emphasizing catalytic processes, including catalytic pyrolysis, deoxygenation, isomerization, and cracking. Drawing insights from the latest literature, the article navigates through recent advancements and challenges in converting authentic pyrolysis oil alternative jet fuel. Special attention is given to elucidating the intricate conversion pathways, shedding light on catalytic pyrolysis and hydrogenation/ hydrodeoxygenation routes.