Effect of Input Power and Process Time on Conversion of Pure and Mixed Plastics into Fuels Through Microwave-Metal Interaction Pyrolysis

This study investigated the effect of input power and process time on microwave-metal interaction pyrolysis of pure plastics (PS, PP, LDPE) and their blends into liquid and gaseous fuels. The microwave power and time were varied to pyrolyze 20 g of each sample in an iron coil. The pure PS underwent maximum conversion into fuels followed by PP and LDPE. Under optimized microwave power (2100–2500 W), PS produced 88.7% oil after 19 min of reaction time, PP produced 54.65% oil at 23 min of reaction time and LDPE produced 30.15% oil after 26 min of reaction time. Pure PS and PP showed high conversion efficiency of 95.40% and 95.10%, respectively, into liquid and gaseous fuels. Pure LDPE showed only 54.30% conversion into fuels by producing large quantity of waxy residue. In blended form, PS-PP blend revealed highest conversion of 65.67% into fuels followed by PS-PP-LDPE blend (57.23%), PS-LDPE blend (46.52%) and PP-LDPE blend (28.08%). Based on mass balance and percentage conversion, PS-PP blend showed maximum conversion of 96.25% whereas PP-LDPE showed minimum conversion of 74.99%. Higher microwave powers within optimal range produced better yield of liquid fuel in shorter time periods. The pyrolytic oils contained some useful aromatic and aliphatic hydrocarbons (C8–C16).