Sustainable recycling and upgrading of waste polytetrafluoroethylene: Current progress and prospect

Resources Conservation and Recycling, Journal Year: 2025, Volume and Issue: 215, P. 108143 - 108143

Published: Jan. 24, 2025

Language: Английский

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Effect of Silica–Alumina Ratio on Catalytic Cracking of Polyethylene over Mesoporous Silica–Zeolite Hierarchical Catalysts Produced by Gel Skeletal Reinforcement

Energy & Fuels, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 6, 2025

Zeolite-containing hierarchical catalysts with microporous ZSM-5 as the core and mesoporous silica shell were successfully prepared by using a gel skeletal reinforcement (GSR) method at zeolite preparation stage. The GSR includes reinforcing reagents hexamethyldisiloxane (HMDS) acetic anhydride (AA), which simultaneously added to mixture of in synthesis ZSM-5. Catalysts SiO2/Al2O3 ratio 84 compared previously investigated 167. extent crystal growth was same HMDS/SiO2 molar range 0–7.5% during hydrothermal 150 °C for 48 h. Crystallization proceeded level samples respective ratios 10 11% when crystallization time extended 72 When catalytic cracking low-density polyethylene (LDPE) performed Curie point pyrolyzer 500 °C, novel catalyst exhibited higher conversion than that 10% moderately gel-reinforced diffused materials from LDPE gave yield reaction products. selectivity toward p-xylene formation xylene improved 10, 11, 12% catalysts, probably due slight blockage micropores coating acid sites outer surfaces crystals GSR-mesoporous silica. Good correlation observed between relative activity estimated conversions, X-ray diffraction measurements, active determined NH3-temperature-programmed desorption, average pore diameter N2 adsorption/desorption suggests size could affect catalysts.

Language: Английский

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Selective catalytic conversion of model olefin and diolefin compounds of waste plastic pyrolysis oil: Insights for light olefin production and coke minimization

Chemical Engineering Journal, Journal Year: 2024, Volume and Issue: unknown, P. 156987 - 156987

Published: Oct. 1, 2024

Language: Английский

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Catalytic Upgrading of Pyrolysis Condensables from Postconsumer Polyolefins Using HZSM-5

Energy & Fuels, Journal Year: 2024, Volume and Issue: 38(21), P. 21162 - 21173

Published: Oct. 15, 2024

The conversion of plastic wastes to monomeric olefins is an attractive means for achieving a circular economy. In our study, fluidized bed reactor converts post-consumer waste high-density polyethylene (HDPE) and polypropylene (PP) mostly condensed pyrolysis waxes some oils, preventing carbon loss gases. condensables were upgraded light (C2–C5) at yields greater than 76 wt % using the HZSM-5 zeolite catalyst post process that employed micropyrolyzer. These results comparable olefin monomer from direct ex situ catalytic original plastics without condensing vapors, highlighting potential applicability this approach in recycling. Our suggest centralized upgrading facility fed by sourced distributed thermochemical processing plants promising pathway Such enables utilization available cracking infrastructure while focusing on setting up close material recovery facilities. energy-dense are more suitable transportation, contributing overall scalability economic viability proposed approach.

Language: Английский

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Fast Catalytic Pyrolysis of Waste Tire for Enhanced Monocyclic Aromatic Hydrocarbons Using Ni Modified Zsm-5 Zeolite Catalyst

Published: Jan. 1, 2024

Incorporating ZSM-5 catalysts into the waste tires (WTs) fast degradation shows great promise for elevating pyrolysis products' quality, and loading Ni metal on can significantly boost catalytic performance. Much research has focused slow processes due to experimental limitations. However, heating is main stream of industrial processing tires, but studies WTs are still rare. As such, this work dedicated exploring influence zeolite process, employing an innovative wire mesh reactor. enhanced yields H2, CH4, aromatics at high temperatures while ensuring oil yield. Introducing changed acid site distribution by reacting with Brønsted acids produce new Lewis sites, ultimately increasing yield monocyclic aromatic hydrocarbons. Two possible routes were proposed based surface pore channel reactions. The findings indicate that utilization modified a viable approach enhancing production high-value products during large-scale WT degradation, offering valuable insights optimizing processes. worth products.

Language: Английский

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Fast Catalytic Pyrolysis of Waste Tire for Enhanced Monocyclic Aromatic Hydrocarbons Using Ni Modified Zsm-5 Zeolite Catalyst

Published: Jan. 1, 2024

Language: Английский

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Thermal oxo-degradation of plastic wastes to valuable compounds

Published: Jan. 1, 2024

As plastic production and environmental accumulation continues to grow, developing new technologies for upcycling wastes is critical. A chemical recycling technology in commercial development pyrolysis, which involves rapidly heating plastics without oxygen present convert into condensable products such as wax oil. These contain a wide variety of chemicals, some can be used building blocks or chemicals. Pyrolysis has shown potential circular economy plastics, but scaling up pyrolysis challenging due heat transfer limitations typical reactors. This work advances thermal oxo-degradation (TOD) an alternative conventional pyrolysis. TOD differs from the process by introducing air reaction. The main benefits are increase rate depolymerization waste provide enthalpy reaction dramatically impacting desired product yields. research defines separate regime gasification, goal producing syngas. Alternatively, herein reported studies use create energy-dense products. Both virgin post-consumer high-density polyethylene polypropylene show enthalpies greater than 2100 J g-1. Comparison showed that partial oxidation reactions release reactor, helping manage endothermic load vapor-phase cracking reactions. By manipulating variables temperature, equivalence ratio, vapor residence time, either majority oxygenated molecules (e.g. alcohols, aldehydes, carboxylic acids) hydrocarbon (paraffins, olefins, diolefins). condensed waxes oils. Oxygenated sole carbon source bioconversion yeasts. Because oils resemble those produced hydrocarbon-rich catalytically upgraded light olefins reintegration economy. shows applied technique overcomes enabling easier scaling. Applying help mitigate our landfills achieve

Language: Английский

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Enhanced Gas/Oil Production from Catalytic Fast Pyrolysis of Polyethylene over Cu/Ce Co-Modified ZSM-5

Waste and Biomass Valorization, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 9, 2024

Language: Английский

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Bifunctional Catalytic Performance of Zn/ZSM-5 in the Aromatization of LPG and the Conversion of Pyrolytic Gases from Recycled Polypropylene

ChemEngineering, Journal Year: 2024, Volume and Issue: 8(6), P. 108 - 108

Published: Oct. 22, 2024

Zn-modified ZSM-5 zeolites with different zinc contents were successfully prepared by the impregnation method and compared unmodified ZSM-5. Their potential for LPG (liquefied petroleum gas) aromatization conversion of pyrolysis gases obtained from recycled polypropylene was subsequently evaluated. In this process, various characterization tests performed on catalysts, including SEM-EDS (scanning electron microscopy energy-dispersive spectroscopy), TPD-NH₃ (temperature-programmed desorption ammonia), FTIR (Fourier-transform infrared spectroscopy). Under optimized conditions, best results 2% Zn/ZSM-5, which generated a higher production BTX (benzene, toluene, xylene) isomers, are major components gasoline. Likewise, in catalytic polypropylene, catalyst aromatic compounds. Therefore, showed excellent performance generating valuable hydrocarbons great industrial interest, particularly aromatics.

Language: Английский

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The Effects of Polyolefin Structure and Source on Pyrolysis-Derived Plastic Oil Composition

Green Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Jan. 1, 2024

Seven types of plastics, from varied structures and sources, were pyrolyzed in a fluidized bed reactor. The resulting oils analyzed by GC×GC, NMR, ICP, while theory experiments combined to explore the degradation mechanism.

Language: Английский

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