A comparative study on pyrolysis of bundle and fluffy shapes of waste packaging plastics

Abstract

The pyrolysis of waste packaging plastic was performed in a semi-batch reactor to study the effect of the shape of reactant on the compositions of pyrolysis oils under N2 gas inflow conditions. Bundle and fluffy shapes of reactants were pyrolyzed at 400 °C for 90 min at N2 inflow rates from 0 to 300 mL/min. The yields of pyrolysis oils were between 67.7 and 76.1% under the reaction conditions, and diesel-like middle oil (C11–C22) was mainly produced with mass fractions over 64%. The main oil product was mostly composed of n-paraffin and n-olefin compounds, and its mass fraction was considerably influenced by the reactant shape and the N2 flow rate. The pyrolysis of the fluff reactant exhibited higher middle oil fractions with higher fraction ratios of n-paraffins to n-olefins than the bundle reactant. This study suggests that the compositions of pyrolysis oil could be controlled by the reactant shape and the N2 inflow, which will provide important information for improving the quality of oil products in a large-scale of pyrolysis processes, and for developing a continuous pyrolysis system because the fluffy shape of reactant is more suitable for continuous feeding.