Upcycling Polyethylene Pyrolysis Oil Into Group IV Base Oil Lubricants

Group IV base oil lubricants, also known as polyalphaolefins (PAO), are a high-value product produced by the petroleum industry for the purpose of lubrication over a wide range of temperatures. In this study, proof-of-concept experiments were conducted to produce PAOs from pyrolyzed waste plastic. Pyrolysis oil containing C8-C17 hydrocarbons in the form of paraffinic alkenes was distilled to acquire C10-C12 α-olefins products which were then oligomerized to form PAO. Key lubricating properties, including viscosity index and pour point, were found to be similar for the pyrolysis-derived synthesized PAO base oils compared to a commercial synthetic lubricant. The synthetic PAO base oil was also found to have a metals (14-21 mg/kg) and sulfur content (10-24 mg/kg) below industry standard. An economic analysis was conducted to determine to potential of targeting high-value products to improve the profitability of pyrolysis technologies. The process economics were found to be dependent on the yield of PAO from the pyrolysis waste plastic, with promising economic results above 4.5% yield of PAO per unit of pyrolyzed plastic. A life cycle assessment found lower GHG emissions from the proposed technology than from conventional petroleum-derived lubricants.