Oil Production from Thermal Liquefaction of Polyethylene in Low-Pressure Superheated Methanol

• • Complete HDPE conversion achieved at ≥260 °C in low-pressure superheated methanol (<0.5 MPa), yielding 77.1% oil with 62.3% alkanes; below 260 °C conversion drops sharply, producing waxy solids—critical threshold for reactor design and energy input. • • At 290 °C, gasoline-range hydrocarbons (C6–C12) surge from 16.6% to 80.9%, demonstrating temperature-driven selectivity toward high-value fuel fractions—enables tuning product slate for market demand. • • Optimal reactant dosage is 0.80 g/mL at 270 °C; deviations reduce conversion due to impaired heat transfer—defines operating window for scale-up to avoid costly inefficiencies. • • Mechanism involves preferential secondary C–C bond scission, radical-mediated secondary reactions (isomerization, cyclization, hydrogenation), with methanol acting as radical source—provides basis for catalyst or process optimization to steer product distribution.