Enhanced Fuel Production through Coprocessing of Syngas and Used Cooking Oil over Fe-Co-K-Mo/γ-Al ₂ O ₃ Catalyst

This study presents an integrated approach to sustainable fuel production by coprocessing raw palm oil-based used cooking oil along with syngas using multifunctional iron-based composite catalysts. Three catalyst systems, Fe-Co-K/γ-Al2O3 (Cat 1), Fe-Co-K-Mo/γ-Al2O3 (Cat 2), and Fe-Co-K-Mo/SiO2 (Cat 3), were synthesized and evaluated in a fixed-bed reactor at 400 °C. Catalyst characterization included BET surface area analysis, NH3-TPD for acidity profiling, H2-TPR, and XRD. Among the catalysts, Cat 2 demonstrated superior performance due to its high surface area (219 m2/g), uniform mesoporosity (41 Å), and balanced acidity, enabling efficient molecular diffusion and selective conversion. It achieved ∼41% CO conversion, 75% liquid hydrocarbon yield, and ∼20% lower hydrogen consumption compared to conventional HEFA processes. The product quality had an iodine number of ∼5 gI2 /100 g and acid number of ∼2 mgKOH/g, attributed to its optimized metal-promoter synergy and support structure. Importantly, the integrated coprocessing strategy supports sustainable fuel synthesis by enabling in situ COx conversion, reducing Scope 1 emissions, and improving carbon utilization efficiency. Additionally, the use of waste-derived feedstocks and syngas aligns with circular carbon economy principles, offering a scalable and environmentally responsible pathway for drop-in hydrocarbon fuel production.