Thermal degradation of polyethylene

Piiroja, E. K.; Lippmaa, H. V.

doi:10.1002/masy.19890270121

Cited by 6 publications

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“…The results indicated that the reaction time resulting in maximum oil yield for the pyrolysis of mixture was shorter than that of the single component. Piiroja and Nikitina31 explored the pyrolysis of waste PE in inert gas at the temperature range 723–808 K. The major products were n ‐alkanes and α‐alkenes. The alkenes were increased as the pyrolysis temperature creased.…”

Section: Introductionmentioning

confidence: 99%

Pyrolysis of tetra pack in municipal solid waste

Chang

2001

J of Chemical Tech & Biotech

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The pyrolysis of tetra pack in nitrogen was investigated with a thermogravimetric analysis (TGA) reaction system. The pyrolysis kinetics experiments for the tetra pack and its main components (kraft paper and low-density poly(ethene) (LDPE)) were carried out at heating rates (b) of 5.2, 12.8, 21.8 K min À1. The results indicated that the one-reaction model and two-reaction model could be used to describe the pyrolysis of LDPE and kraft paper respectively. The total reaction rate of tetra pack can be expressed by the summation of the individual class of LDPE and kraft paper by multiplying the weighting factors. The pyrolysis products experiments were carried out at a constant heating rate of 5.2 K min À1. The gaseous products were collected at room temperature (298 K) and analyzed by gas chromatography (GC). The residues were collected at some signi®cant pyrolysis reaction temperatures and analyzed by an elemental analyzer (EA) and X-ray powdered diffraction (XRPD). The accumulated masses and the instantaneous concentrations of gaseous products were obtained under the experimental conditions. The major gaseous products included non-hydrocarbons (CO 2 , CO, and H 2 O) and hydrocarbons (C 1±5 ). In the XRPD analysis, the results indicated that pure aluminum foil could be obtained from the ®nal residues. The proposed model may be supported by the pyrolysis mechanisms with product distribution. # 2001 Society of Chemical Industry Keywords: tetra pack; kinetic model; pyrolysis products; recyclingA of pyrolysis reaction (1) of kraft paper,A of pyrolysis reaction (2) of kraft paper,E of pyrolysis reaction (1) of kraft paper,E of pyrolysis reaction (2) of kraft paper,Weighting factor taking account of the decrease in M contributed by the pyrolysis reaction of kraft paper in tetra pack (dimensionless)Weighting factor taking account of the decrease in M contributed by the pyrolysis reaction of LDPE in tetra pack (dimensionless)Weighting factor taking account of the decrease in M contributed by the pyrolysis reaction (1) of kraft paper,Weighting factor taking account of the decrease in M contributed by the pyrolysis reaction (2) of kraft paper,k of pyrolysis reaction (1) of kraft paper = A 1 exp(ÀE 1 /RT),Residual mass fraction at time t or at temperaturen of pyrolysis reaction (1) of kraft paper, n 1 = n k1 (dimensionless) n 2 , n k2 n of pyrolysis reaction (2) of kraft paper, n 2 = n k2 (dimensionless) r Degradation rate = dX/dt (s À1 ) R Universal gas constant = 8.314 Â 10 Volatiles produced by pyrolysis reactions (1) and (2)

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Section: Introductionmentioning

confidence: 99%

Pyrolysis of tetra pack in municipal solid waste

Chang

2001

J of Chemical Tech & Biotech

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“…But the third mechanism increased the extent of initial decomposition. 9 Based on the two-reaction model, the gaseous product distribution of uncoated printing and writing paper pyrolyzed in nitrogen was investigated by Wu et al 10 The major gaseous products were non-hydrocarbons (H 2 , CO, CO 2 , and H 2 O) and hydrocarbons (C 1-3 , C 4 , C 5 , C 6 , 1-ring aromatics, C 10-12 , levoglucosan, C [13][14][15] , and C [16][17][18] ). The cumulated masses and the instantaneous concentrations (at intervals of 25 K from 488 to 938 K) of gaseous products were obtained under the heating rate (HR) of 5 K/min.…”

Section: Introductionmentioning

confidence: 99%

“…The results indicated that the reaction time resulted in maximum oil yield for the pyrolysis of mixture was shorter than that of single component. Piiroja and Nikitina 15 explored the pyrolysis of waste PE in inert gas at a temperature range of 723-808 K. The major products were n-alkanes and R-olefins. The alkenes were increased as the pyrolysis temperature increased.…”

Section: Introductionmentioning

confidence: 99%

Pyrolysis Products of Tetra Pack in Different Oxygen Concentrations

Yu-fen

2001

Energy Fuels

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The tetra pack is one of the principal materials in municipal solid wastes (MSW). The amount of waste tetra pack is over 6000 tons per year in Taiwan. The components of tetra pack are kraft paper (about 70 wt %), low-density polyethylene (LDPE, about 25 wt %), and aluminum foil (about wt 5%), generally. Accordingly, its conversion to useful fuels as well as the recycling aluminum foil has become a worthy goal from not an economic, but also from an environmental standpoint. In this study, the experiments for the partial oxidation of tetra pack were carried out with a thermogravimetric analysis (TGA) reaction system. The pyrolysis reactions of tetra pack were performed in four different oxygen concentrations (C O 2 ) of 5.4, 10.4, 14.8, and 21.0% for analyzing the pyrolysis products. The gaseous products were collected at room temperature (298 K) and analyzed by gas chromatography (GC). The residues were collected at the pyrolysis temperatures 575, 656, 700, 730, and 1073 K and analyzed by elemental analyzer, and X-ray powdered diffraction (XRPD). The cumulated masses and the instantaneous concentrations of gaseous products corresponding to the different oxygen concentrations were obtained under the experimental conditions. The recovery of total gaseous products based on the mass of tetra pack sample was over 88% for four different oxygen concentrations. The major gaseous products of tetra pack pyrolysis reaction were CO2, CO, H2O, and hydrocarbons (HCs). The hydrocarbons mainly consist of low molecular paraffins and olefins (C1 - 5). The percentages of C1 - 5 relative to the total hydrocarbons gases were about 69.9, 71.1, 74.3, and 68.8 wt % for tetra pack pyrolysis in C O 2 = 5.4, 10.4, 14.8, and 21.0%, respectively. In the XRPD analysis, the results indicated that a high-purity aluminum foil could be obtained from the final residues.

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Alkaline fungal degradation of oxidized polyethylene in black liquor: Studies on the effect of lignin peroxidases and manganese peroxidases

Mukherjee

Kundu

2014

J of Applied Polymer Sci

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High-molecular-weight polyethylene is resistant to natural environmental degradation for its crystalline, hydrophobic structure. In this study, waste polyethylene bags are chemically oxidized at 80 C for 5 days by potassium dichromate solutions of various concentrations along with sulfuric acid. Absorbance peaks of carbonyl and carboxylate ions in the Fourier transform infrared spectroscopy spectra and formation of amorphous phase from crystalline one as indicated in X ray diffraction studies of oxidized polyethylenes indicate the formation of a polar hydrophilic and low-molecular-weight material after oxidation. From the scanning electron microscopy studies, it is observed that reacted polyethylene surface is disintegrated and numerous fissures are formed throughout the surface. The respective weight loss of incubated oxidized polyethylene with Phanerochaete chrysosporium (MTCC-787) after 15 days of incubation is 70%, respectively, in black liquor-glucose-malt extract medium. As both lignin peroxidase (LiP) and manganese peroxidase (MnP) were detected in this media, further degradation of oxidized polyethylene is carried out in four different media with varying amount of N and Mn. The weight loss is observed only in media with excess nitrogen (N) and limited manganese (Mn), the condition which enhances the presence of LiP and MnP. This indicates that these enzymes are essential for degradation of lignin as well as oxidized polyethylene. UV spectroscopic studies indicate 40% decrease in the lignin concentration. This process of fungal degradation of chemically oxidized polyethylene using black liquor is very quick compared to the other related studies, leading to the simultaneous degradation of two waste materials, polyethylene and black liquor.

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Thermal degradation of polyethylene

Cited by 6 publications

References 0 publications

Pyrolysis of tetra pack in municipal solid waste

Pyrolysis of tetra pack in municipal solid waste

Pyrolysis Products of Tetra Pack in Different Oxygen Concentrations

Alkaline fungal degradation of oxidized polyethylene in black liquor: Studies on the effect of lignin peroxidases and manganese peroxidases

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