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The co-pyrolysis of polyethylene terephthalate (PET) with low-density polyethylene (LDPE) and high-density polyethylene (HDPE) was carried out in a batch steel pyrolyzer in order to convert the PET into pyrolysis oil as its pyrolysis alone resulted in wax and gases. The study also aimed to increase the aromatic content of pyrolysis oil by the interaction of degradation fragments of linear chains of LDPE and HDPE with the benzene ring of PET during the pyrolysis. The reaction conditions were optimized for a higher yield of pyrolysis oil which were found to be 500 °C pyrolysis temperature with a heating rate of 0.5 °Cs−1, 1 h reaction time and 20 g of the initial mass of polymer mixture having 20% PET, 40% LDPE and 40% HDPE. Waste aluminium particles were applied as an economical catalyst in the process. The thermal co-pyrolysis yielded 8% pyrolysis oil, 32.3 wax, 39.7 wt% gases and 20% coke while the catalytic co-pyrolysis produced 30.2% pyrolysis oil, 4.2% wax, 53.6 wt% gases and 12% coke. The fractional distillation of catalytic oil resulted in 46% gasoline range oil, 31% kerosene range oil and 23% diesel range oil. These fractions resembled the standard fuels in terms of their fuel properties as well as FT-IR spectra. The GC-MS analysis revealed that the catalytic co-pyrolysis favoured the formation of relatively short-chain hydrocarbons with olefins and isoparaffins as major components while the thermal co-pyrolysis formed long-chain paraffins. The naphthenes and aromatics were also found in higher amounts in the catalytic oil compared with the thermal oil. [ABSTRACT FROM AUTHOR]

BACKGROUND: Municipal waste contains low density polyethylene (LDPE), high density polyethylene (HDPE), and polyethylene terephthalate (PET) in enormous amount. As these plastics are non‐biodegradable and pose serious threats to the environment, efforts have been made towards their safe disposal with energy recovery and value added chemicals by subjecting them to heat under oxygen deficient conditions. This study deals with the co‐pyrolysis of the three types of waste polymers, with special focus on the conversion of PET into liquid fuel by its interaction with the other two polymers. Results: The individual pyrolysis of LDPE and HDPE produced pyrolysis oil, whereas PET produced only wax. The co‐pyrolysis of the three polymers with different mixing ratios showed that PET hindered oil formation and increasing its amount more than 20 wt% in the polymer mixture resulted in wax formation. The thermal process produced 8 wt% pyrolysis oil, 32.3 wt% wax, 39.7 wt% pyro‐gases and 20 wt% coke while the catalytic process with copper catalyst produced 32.5 wt% pyrolysis oil, 3 wt% wax, 46.5 wt% pyro‐gases, and 18 wt% coke under optimum conditions. Conclusion: The thermal pyrolysis oil contained long chain paraffins as major components, while short chain isoparaffin and naphthenes were predominant in the catalytic pyrolysis oil owing to which marked differences were observed in the physicochemical properties of both oils. The fractionally distilled fractions of catalytic pyrolysis oil in gasoline, kerosene, and diesel range showed profound similarities with standard fuels in terms of fuel properties particularly the gasoline range fraction. © 2022 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

A wild aquatic plant, Eichhornia Crassipes, and polyethylene have been converted into liquid product thermo-catalytically and cost effectively through co-pyrolysis using batch steel pyrolyzer. The Fe and CaCO3 catalysts were obtained as wastes from various mechanical processes. The catalytic process was compared with non-catalytic pyrolysis. The effect of various reaction conditions was investigated in order to find out the optimized process conditions. It was found that the favorable reaction conditions were 450 °C temperature and 1-h reaction time at a heating rate of 1 °C/s and 0.4-mm biomass particle size. The bio-oil yield was found to be 34.4% and 26.6% using Fe and CaCO3 respectively with catalysts particle size of 0.4 mm at the optimized reaction conditions and 5 wt% of biomass. The non-catalytic and catalytic co-pyrolysis using Fe as catalyst produced 23.9% and 28.7% oil respectively. Thus the efficiency of processes in terms of bio-oil production was found in order of: Fe > CaCO3 > non-catalytic pyrolysis. The GC/MS analysis of n-hexane extract of bio-oil shows that Fe catalyst favors formation of aliphatic hydrocarbons while CaCO3 and non-catalytic pyrolysis favors formation of aromatic hydrocarbons. Mostly unsaturated aliphatic hydrocarbons were formed in case of co-pyrolysis reactions. The calorific value of bio-oil was also measured in order to find out the fuel properties of the products. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]