Plastic waste to liquid oil through catalytic pyrolysis using natural and synthetic zeolite catalysts

• Published in: Waste management (Elmsford) 2017-11, Vol.69, p.66-78
• Main Authors: Miandad, R., Barakat, M.A., Rehan, M., Aburiazaiza, A.S., Ismail, I.M.I., Nizami, A.S.
• Format: Article
• Language: English
• Subjects: Alternative fuel; ALTERNATIVE FUELS; Catalyst; CATALYSTS; FOURIER TRANSFORMATION; Fuel Oils; GAS CHROMATOGRAPHY; Gas Chromatography-Mass Spectrometry; Hydrocarbons - analysis; INFRARED SPECTRA; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; LIQUID FUELS; Liquid oil; MASS SPECTROSCOPY; Natural zeolite; OIL YIELDS; Plastic waste; Plastics - analysis; Polyethylene - analysis; Polystyrenes - analysis; PYROLYSIS; Recycling - methods; WASTE OILS; Waste Products - analysis; ZEOLITES
• ISSN: 0956-053X; 1879-2456
• DOI: 10.1016/j.wasman.2017.08.032

[Display omitted] •Liquid fuel was produced from plastic waste through catalytic pyrolysis.•Pyrolysis of polystyrene plastic produced highest liquid oil yield of 54% using natural zeolite.•Pyrolysis liquid oil mainly consisted of aromatic hydrocarbons with a few aliphatic compounds.•Primary compounds in liquid oil were styrene, ethylbenzene, benzene, azulene, and naphthalene.•Liquid oil had high heating values (HHV) of 40.2–45MJ/kg. This study aims to examine the catalytic pyrolysis of various plastic wastes in the presence of natural and synthetic zeolite catalysts. A small pilot scale reactor was commissioned to carry out the catalytic pyrolysis of polystyrene (PS), polypropylene (PP), polyethylene (PE) and their mixtures in different ratios at 450°C and 75min. PS plastic waste resulted in the highest liquid oil yield of 54% using natural zeolite and 50% using synthetic zeolite catalysts. Mixing of PS with other plastic wastes lowered the liquid oil yield whereas all mixtures of PP and PE resulted in higher liquid oil yield than the individual plastic feedstocks using both catalysts. The GC–MS analysis revealed that the pyrolysis liquid oils from all samples mainly consisted of aromatic hydrocarbons with a few aliphatic hydrocarbon compounds. The types and amounts of different compounds present in liquid oils vary with some common compounds such as styrene, ethylbenzene, benzene, azulene, naphthalene, and toluene. The FT-IR data also confirmed that liquid oil contained mostly aromatic compounds with some alkanes, alkenes and small amounts of phenol group. The produced liquid oils have high heating values (HHV) of 40.2–45MJ/kg, which are similar to conventional diesel. The liquid oil has potential to be used as an alternative source of energy or fuel production.