Continuous flow hydroprocessing of waste plastics using ionic liquid catalyst

The present study attempted continuous flow hydroprocessing of waste plastics utilizing an ionic liquid-based catalyst to obtain diesel-like hydrocarbon fractions. Continuous flow processing offers higher efficiency and cost-effectiveness for commercial production. The ionic liquid (IL) improves the dispersion of active metal species and enhances mass-transfer properties, enabling efficient product formation at lower temperatures (180 °C) compared to conventional hydroprocessing catalysts (300–450 °C). The catalyst comprised of Palladium metal impregnated on mesoporous SBA-15 silica coated with 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMIM NTf2) ionic liquid. The reaction was performed at 180 °C and 65 bar under H2, with Weight Hourly Space Velocity maintained at 1 h⁻¹. Hydroprocessing resulted in the formation of 52.95% n-paraffins, 21.57% iso-paraffins and 25.48% aromatics as a result of hydrocracking, hydro-isomerisation and hydro-aromatization respectively. The total paraffin and aromatic content of the product (HMWPO) resulted in a 95% similarity to the commercial diesel. Also, the physicochemical properties of HMWPO aligned within EN 590 diesel standards. HMWPO was blended with commercial diesel at 10–40% volumetric ratios. The engine trials of HMWPO offered comparable combustion and emission profiles with diesel. The integrated approach of continuous processing using Pd/SBA-15/BMIM NTf2 catalysis delivered an energy efficient pathway to commercialize plastic waste to diesel like fuel.