Microwave Pyrolysis of Polypropylene with Iron Susceptor

The improper disposal of plastic waste and low recycling rate have caused various environmental issues around the world. Therefore, microwave metal pyrolysis approach is proposed to efficiently convert plastic waste into liquid fuel, wax and gaseous by-products. This study aims to investigate the effect of different parameters such as microwave power and mass of metal on the product formation of the pyrolysis of polypropylene (PP). The experimental study was conducted in a closed glass reactor with a capacity of 500 ml, in a modified 2.45 GHz microwave, at a pressure of 1 atm and nitrogen is flowed at 0.5 L/min. The plastic was mixed with iron (Fe) powder and pyrolysed for 30 min. The produced pyrolysis vapor was condensed in a two-stage condenser where the oil formed was subsequently collected in a flask. The increase in microwave power from 500 to 700 W increased the oil yield of PP with iron powder from 22.4 to 54.5 wt.% and decreased the wax yield from 40.2% to zero. The increase in mass of iron powder from 5 to 10 g improved the oil yield from 20.0 to 54.5 wt.%, while the oil yield slightly decreased to 50.1 wt.% at 15 g. The pyrolysis oil formed has high calorific value of 45-46 MJ/kg comparable with the commercial fuel, thus the fuel can be blended with pure diesel to reduce the portion of fossil fuel in diesel combustion engine application.