Investigating the Pyrolysis Process of Polyethylene in the Presence of Biochar Catalyst to Convert iT into Liquid Fuel

In this study, the effect of biochar catalyst on the pyrolysis process of light (LDPE), heavy (HDPE), and mixed polyethylene was investigated. For this aim, 30 grams of sample was loaded in a laboratory-sized reactor and pyrolyzed at 500°C under atmospheric pressure. The amount of gas produced in the presence of catalysts decreased 11.96 and 16.08 wt% for HDPE and mixed polyethylene, but not for LDPE, indicating an increase in heavy vapor cracking. The amount of wax produced in the presence of a catalyst has increased 5.94 and 3.59 wt% for HDPE and mixed polyethylene excluding LDPE. The amount of liquid product obtained was increased for all three samples in the presence of biochar catalysts (from 12.30 to 16.69, from 38.21 to 46.19, and from 4.47 to 16.97 wt% for LDPE, HDPE, and mixed, respectively). Biochar increased the propane content for all three samples. This was due to the increase in cracking and conversion of heavy molecules to propane. Ethane content for LDPE decreased while for HDPE increased. This is indicating more breakdown of HDPE molecules and reaction of molecules with each other and with ethane to other products such as propane. Liquid product analysis showed that biochar catalysts tended to reduce compounds such as alcohols, indicating a tendency to deoxidize. In addition, biochar also caused the breakdown of larger and smaller aromatic molecules. The catalyst analysis indicated the presence of a coke layer on the catalyst, which contained more aromatic and oxygenated compounds.