Thermo-catalytic co-pyrolysis of recovered heavy oil and municipal plastic wastes

• Mixtures of MPW and heavy oil were pyrolyzed in a batch reactor.
• MPW/heavy oil ratio had a significant effect to the product properties.
• The catalysts activity were more significant at lower MPW/heavy oil ratio.
• Concentrations of contaminant have decreased in case of MPW/heavy oil co-pyrolysis.
• Ni-Mo-catalyst promoted the production of cyclic hydrocarbons.

In this work municipal plastic wastes were co-pyrolyzed together with waste plastic derived heavy oil at 500 °C in a stirred batch reactor using β-zeolite, y-zeolite and m-Ni-Mo-catalysts. The effect of the heavy oil/municipal plastic waste ratio to the product properties was basically investigated. Higher pyrolysis oil and gas yields were observed by the using of catalyst and by the re-using of heavy oils. Catalysts could be affecting especially the concentration of hydrogen, isobutene and isopentane in gases. Both pyrolysis oil and heavy oil contained paraffin, olefins, aromatics and cyclic compounds, while the heavy oil had hydrocarbons with higher molecular weight. Based on GC–MS and EDXRFS results the composition of pyrolysis oil and their contaminants were significantly affected by both the waste plastic/heavy oil ratio and catalyst presence. Lower waste plastic/heavy oil ratio and selected catalyst could efficiently decrease the concentration of contaminants and increase the valuable hydrocarbon content.