Investigating the catalytic pyrolysis of polyethylene terephthalate in the presence of zeolite catalyst to convert it into liquid fuel

In this work, the effect of zeolite catalyst on the pyrolysis process of polyethylene terephthalate (PET) was investigated. For this aim, 15 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 increased 8 wt%, which indicates an increase in the cracking reaction rate. The amount of wax produced in the presence of catalyst has decreased 10 wt%. The amount of liquid product obtained was increased in the presence of zeolite catalysts (from 23 to 26.5wt%). zeolite increased the propane content, which indicates an increase in cracking and conversion of heavy molecules to propane. Ethane levels increased, indicating further breakdown of heavy molecules of polyethylene terephthalate and the reaction of molecules with each other and with ethane and conversion to other products such as methane. Liquid product analysis showed that zeolite catalysts tended to reduce acidic compounds, indicating a tendency to deoxygenate or convert acids to other compounds. In addition, zeolite has also converted compounds with more than one benzene ring to compounds with one ring. Therefore, zeolite catalysts simultaneously deoxygenate and molecularly breakdown heavy compounds in the liquid product.The catalyst analysis indicated the presence of a coke layer on the catalyst, which contained more aromatic and oxygenated compounds.