Standard diesel production from mixed waste plastics through thermal pyrolysis and vacuum distillation

Abstract

Plastic pyrolysis oil (PPO) was produced in a pilot-scale batch pyrolysis reactor at 540 °C from mixed waste plastic (MWP) (high-density polyethylene (HDPE), polypropylene (PP) and polystyrene (PS)). The produced PPO was then distilled in a vacuum distillation unit and diesel was obtained at temperatures between 170 and 380 °C along with light petrol (<170 °C) and heavy residue (>380 °C). This study found that MWP can produce over 80% liquid oils without operational problems or wax formation. Distilled PPO produces 49.5–53% diesel, 39 – 46.5% petrol and residue 1.5 – 8% by weight. Although PPO has calorific value ranging from 43.85 to 45.26 MJ/kg like commercial diesel however, PPO is not suitable for direct use in diesel engine for low kinematic viscosity (KV) and density values at 1.1–1.26 mm2/s and 0.78 – 0.83 gm/cm3 respectively. For the distilled diesel cut (DC), KV, density, higher heating value (HHV), cetane index (CI), aromatic hydrocarbon (AH) and poli-aromatic hydrocarbon (PAH) were found 1.95–2.15 mm2/s, 0.81 – 0.85 gm/cm3, 44.92–46.36 MJ/kg, 46 – 58, 18.81 – 35.1% and 4.81 – 11.9% respectively indicating better option for direct use as automobile diesel with significant effect of HDPE amount present in feedstock.