Sustainable biochemicals and fuels from catalytic fast co-pyrolysis of biomass and waste plastics

In a pioneering stride towards sustainable energy, this study introduces the ex-situ catalytic fast co -pyrolysis (ESCCP) of Calophyllum inophyllum (CI) seeds which is a biomass rich in oil and waste polystyrene (WPS), leveraging calcium oxide (CaO) as a catalyst to enhance pyrolytic oil (PO) production. Thermal pyrolysis of CI seeds at 550 °C yielded substantial PO, while thermal co-pyrolysis at an 8:2 CI:WPS ratio enhanced PO yield, raised calorific value (CV), lowered viscosity, reduced acids (from 46.25% to 22.42%), increased aromatics (to 8.86%), and enriched diesel-range hydrocarbons (C8–C21) to 92.38%. Ex-situ catalysis with 5% CaO further boosted PO yield to 70.86%, CV to 44.92 MJ/kg, and diesel hydrocarbons to 99.22%, with deoxygenation decreasing acids to 25.76%. At 10% CaO, CV reached 47.06 MJ/kg and viscosity dropped to 4.75 cP. Distillation fractions mimicked crude oil (gasoline up to 11.89%, kerosene 48.44%, aviation gasoline 36.35%), with GC–MS confirming dominant alkanes, alkenes, and fatty acids (e.g., oleic, palmitic). This innovative dual-feedstock approach not only valorizes abundant biomass and plastic waste but also delivers a scalable, high-quality biofuel with properties rivaling conventional fossil fuels.