Characteristics of fractionated drop-in liquid fuel of plastic wastes from a commercial pyrolysis plant

Abstract

Pyrolysis is a waste conversion technology to solve an increasing plastic waste issue worldwide. Waste plastic pyrolysis fuel from a commercial-scale pyrolysis plant (10 ton/day) was comprehensively investigated using distillation methods by separating the crude pyrolysis fuel to isolate the diesel-like pyrolysis fuel fraction (C₉-C₂₅ for fraction 2 + fraction 3, middle distillate). Other fractions were C₅-C₁₀ for the light distillate (fraction 1), and >C₂₅ for the heavy distillate (fraction 4). The relationship between the fuel boiling point and liquid vapor temperature were found for designing a scaled-up oil separation process. The diesel grade pyrolysis fuel fraction comprised approximately 70-80% of the crude pyrolysis fuel, wherein it had values of 43-45 MJ/kg, 1-6 cSt, and 12-42 mg_KOH/g_oil. Meanwhile, the elemental ratios of the crude pyrolysis oil improved to 0.1 for O/C and 1.9 for H/C after separation, close to petroleum fuels (0.0 O/C and 1.95 H/C). The highest relative chemical composition was the olefins (46% in fraction 1 and 41% in fraction 2), whereas the paraffin was approximately 15-20% in the light fraction. Finally, the potential CO₂ reduction for the plastic waste-to-energy process was evaluated, revealing that a total of 0.26 tCO₂/ton_waste of emissions could be avoided during the waste plastic pyrolysis process.

Keywords: CO(2) carbon footprint; Distillation; Fractionation; Plastic waste; Pyrolysis oil.