Production of Biogasoline from Plastic Waste through Pyrolysis Using a Temperature-Controlled Condenser Technique

Plastic waste has become an environmental problem because it has low recyclability, and it takes time to degrade. Pyrolysis of these wastes represents a promising alternative to transform waste plastic bags into useful fuels. The focus of this work is on the production of bio-oil derived from used plastic bags, via a fixed-bed pyrolysis unit coupled with a hot biochar bed and temperature-controlled condensation setup. The operation temperature of this setup is set at 500 °C, with condensation temperature in the range from -10 to -40 °C, in order to investigate vapor fractionation behavior as well as improved fuel quality. Based on the experimental outcomes, it is observed that lowering the condensation temperature leads to substantial augmentation in the yield of low-molecular-weight hydrocarbons, with an increasing amount of bio-oil from 10.5% at -10 °C to 32.7% at -40 °C, concurrent with a reduction in gas yield, observed from 27.4% to 5.4%, respectively. Gas chromatography-mass spectrometry (GC-MS) analysis of the samples further identifies benzene and toluene as major constituents at lower temperatures (-40 °C and -30 °C), as compared to longer-chain compounds like cyclononane at higher temperatures (-20 °C and -10 °C). The fuel characteristics such as heating value (41.2 to 42.9 MJ/kg), density (723.5 to 741.8 kg/m³), and viscosity (0.7 to 1.2 cSt) are close to gasoline standards. The presence of a large amount of paraffin with negligible oxygenates has been further ensured using Fourier transform infrared spectroscopy (FTIR). This clearly shows that the use of controlled condensation and biochar filtration helps in creating a strong potential for the reduction of low-cost plastic waste into cleaner bio-oil.