Oil and gas production from the pyrolytic transformation of recycled plastic waste: An integral study by polymer families

Abstract

Different plastics recovered from a local urban solid waste plant were collected before landfilling, separated, and classified by families, i.e. polyethylene (PE), polypropylene (PP), high impact and expanded polystyrene (HIPS and EPS, respectively), polyethylene terephthalate (PET), and polyvinyl chloride (PVC). A systematic pyrolysis study was carried out to compare the different behavior registered in each plastic type, and an integral analysis of the produced oils and synthetic gas was conducted. In general terms, the oil yield followed the order EPS > PP > PE > HIPS > PET > PVC, reaching maximum values over 500 °C after 1 h of treatment. The oil from HIPS, EPS, PET, and PP was rich in light compounds, i.e., C5-C9 hydrocarbons. Almost 100 % of the oil from HIPS and EPS pyrolysis was aromatic. The aromatic fraction was important in the case of PVC (57 %) and PET (45 %). PE produced an oil with the most varied distribution of compounds but rich in olefins (67 %). The analysis of the non-condensable composition of the gas showed that in all the pyrolysis gases methane was over 50 % (vol.), followed by ethane in importance. CO was produced in the case of PET.