Slow pyrolysis of waste polyethylene terephthalate yielding paraldehyde, ethylene glycol, benzoic acid and clean fuel

• Published in: Polymer degradation and stability Vol. 198; p. 109900
• Main Authors: Straka, Pavel, Bičáková, Olga, Šupová, Monika
• Format: Journal Article
• Language: English
• Published: London Elsevier Ltd 01-04-2022; Elsevier BV
• Subjects: Antifreeze solutions; Benzoates; Benzoic acid; Clean fuel; Clean fuels; Ethylene glycol; Industrial applications; Low temperature; Low temperature physics; Paraldehyde; Polyethylene terephthalate; Pyrolysis; Raw materials; Waste PET; Benzoic acid; Waste PET; Pyrolysis; Ethylene glycol; Paraldehyde; Clean fuel
• ISSN: 0141-3910; 1873-2321
• DOI: 10.1016/j.polymdegradstab.2022.109900

•The low-temperature slow pyrolysis of PET waste was studied.•This waste could be completely pyrolyzed at 25 °C min−1 to final temperature 400 °C.•An intensive thermal activation at a heating rate of 40 °C min−1 to 200 °C is needed.•Main components of obtained oil were paraldehyde, ethylene glycol, benzoic acid and benzoates.•All obtained products are well applicable in practice.
The low-temperature slow pyrolysis of PET waste was studied. After intensive thermal activation, the waste PET could be completely pyrolyzed at 25 °C min−1 to the final temperature of 400 °C. The main components of the resulting oil were paraldehyde (54.7 wt.%) and ethylene glycol (23.7 wt.%); further, benzoic acid and benzoates were obtained. Such products represent valuable intermediates for industrial use or other applications. In addition, the pyrolysis produced a solid carbonaceous residue, particularly usable as a low-ash and low-sulfur smokeless fuel (HHV 31.3, LHV 30.4 MJ kg−1). Thus, the low-temperature pyrolysis of PET waste yields products that are easy to put to use with no demands on the purity of the feedstock.
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