Hydrocracking of virgin and post-consumer polymers

Jumah, Abdulrahman bin; Tedstone, Aleksander A.; Garforth, Arthur

doi:10.1016/j.micromeso.2021.110912

Cited by 22 publications

(18 citation statements)

References 35 publications

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“…Jumah and coworkers [170] treated low-and high-density polyethylene (LDPE, HDPE), polypropylene (PP), and polystyrene (PS) to produce liquid petrol gas (C3-C4) and naphtha. They reported the effect of both the catalyst morphology (beta zeolite impregnated with 1% Pt) and the feed stream variation, by reacting different polymers individually and post-consumer polymer mixtures.…”

Section: Hydrocrackingmentioning

confidence: 99%

Recent Advancements in Plastic Packaging Recycling: A Mini-Review

et al. 2021

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Today, the scientific community is facing crucial challenges in delivering a healthier world for future generations. Among these, the quest for circular and sustainable approaches for plastic recycling is one of the most demanding for several reasons. Indeed, the massive use of plastic materials over the last century has generated large amounts of long-lasting waste, which, for much time, has not been object of adequate recovery and disposal politics. Most of this waste is generated by packaging materials. Nevertheless, in the last decade, a new trend imposed by environmental concerns brought this topic under the magnifying glass, as testified by the increasing number of related publications. Several methods have been proposed for the recycling of polymeric plastic materials based on chemical or mechanical methods. A panorama of the most promising studies related to the recycling of polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), and polystyrene (PS) is given within this review.

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Section: Hydrocrackingmentioning

confidence: 99%

Recent Advancements in Plastic Packaging Recycling: A Mini-Review

et al. 2021

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“…The polymer hydrocracking performance of the catalyst used has been explored extensively in our previous studies, which demonstrate the effect of other zeolite supports, as well as the influence of temperature, reaction time, and the agitation rate. 26 The key properties, characterization, and product distribution of the catalyst, 1% Pt-β, used in this study for kinetic modeling of LDPE are discussed next.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

“…This present paper introduces a kinetic study of hydrocracking the environmentally problematic polymer, LDPE, over 1% platinum-impregnated zeolite β in a batch reactor with consideration of the mass transfer and the internal diffusion limitations. In our previous studies, , we investigated a number of zeolites for hydrocracking of the polymer, and platinum-impregnated zeolite β was chosen for this study based on its higher performance. The advantage of zeolite β is the large pore size, allowing diffusion of polymeric macromolecules into the acidic active sites.…”

Section: Introductionmentioning

confidence: 99%

Kinetic Modeling of Hydrocracking of Low-Density Polyethylene in a Batch Reactor

Jumah

Malekshahian

Tedstone

et al. 2021

ACS Sustainable Chem. Eng.

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Hydrocracking offers potential for the selective recovery of useful chemical fractions from polyolefin waste at relatively moderate reaction conditions with the possibility of heteroatom and contaminant tolerance. This study develops a kinetic model for low-density polyethylene (LDPE) hydrocracking over a bifunctional zeolite, namely, 1%Pt-β, using a lumping model that describes the kinetics in a batch process. In developing the kinetic model, mass transfer limitations and vapor–liquid equilibrium were taken into consideration. Kinetic parameters were estimated from experimental results obtained at a hydrogen pressure of 20 bar and different reaction temperatures (250–300 °C) as well as different batch reaction times (0–40 min). Kinetic parameters, mass transfer coefficients, and effectiveness factors were determined using a nonlinear regression model of the experimental results via MATLAB software. The physical properties of the product streams as well as vapor–liquid equilibrium data of the system were estimated using the flash unit in Aspen HYSYS software. The product stream was dominated by the naphtha fraction, decreasing with longer batch times. The results of the model indicate mild gas–liquid mass transfer limitation and unavoidable diffusion limitations of the macromolecules of molten LDPE and heavy liquid through the catalyst pores, especially at high reaction temperatures.

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“…In principle, direct back‐to‐monomer molecular recycling appears to be feasible by hydropyrolysis in the presence of bifunctional platinum‐doped zeolites under mild conditions (330 °C, 20 bar hydrogen pressure, and 30 min residence time). [ 485 ] Thus, hydropyrolysis transforms single and mixed streams of virgin and post‐consumer plastics such as HDPE, LDPE, and PP into liquid hydrocarbons that can serve as a renewable carbon source for polyolefins, whereas PS is hydrocracked to yield benzene and ethylbenzene, which are useful as raw materials for virgin PS production. [ 485 ] Hydropyrolysis occurs in the presence of hydrogen or water, for example, Shell's IH 2 process, extracts value from non‐edible biomass, aquatic plants, and (ligno)cellulosic fractions of municipal wastes, by converting them into sustainable fuels and chemicals.…”

Section: Molecular Recyclingmentioning

confidence: 99%

“…[ 485 ] Thus, hydropyrolysis transforms single and mixed streams of virgin and post‐consumer plastics such as HDPE, LDPE, and PP into liquid hydrocarbons that can serve as a renewable carbon source for polyolefins, whereas PS is hydrocracked to yield benzene and ethylbenzene, which are useful as raw materials for virgin PS production. [ 485 ] Hydropyrolysis occurs in the presence of hydrogen or water, for example, Shell's IH 2 process, extracts value from non‐edible biomass, aquatic plants, and (ligno)cellulosic fractions of municipal wastes, by converting them into sustainable fuels and chemicals. [ 486 ] In BtL conversion, (hydro)pyrolysis, gasification, liquefaction, and Fischer–Tropsch processes gain fuels from biomass.…”

Section: Molecular Recyclingmentioning

confidence: 99%

Closing the Carbon Loop in the Circular Plastics Economy

Schirmeister

Mülhaupt

2022

Macromol. Rapid Commun.

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Today, plastics are ubiquitous in everyday life, problem solvers of modern technologies, and crucial for sustainable development. Yet the surge in global demand for plastics of the growing world population has triggered a tidal wave of plastic debris in the environment. Moving from a linear to a zero‐waste and carbon‐neutral circular plastic economy is vital for the future of the planet. Taming the plastic waste flood requires closing the carbon loop through plastic reuse, mechanical and molecular recycling, carbon capture, and use of the greenhouse gas carbon dioxide. In the quest for eco‐friendly products, plastics do not need to be reinvented but tuned for reuse and recycling. Their full potential must be exploited regarding energy, resource, and eco‐efficiency, waste prevention, circular economy, climate change mitigation, and lowering environmental pollution. Biodegradation holds promise for composting and bio‐feedstock recovery, but it is neither the Holy Grail of circular plastics economy nor a panacea for plastic littering. As an alternative to mechanical downcycling, molecular recycling enables both closed‐loop recovery of virgin plastics and open‐loop valorization, producing hydrogen, fuels, refinery feeds, lubricants, chemicals, and carbonaceous materials. Closing the carbon loop does not create a Perpetuum Mobile and requires renewable energy to achieve sustainability.

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Hydrocracking of virgin and post-consumer polymers

Cited by 22 publications

References 35 publications

Recent Advancements in Plastic Packaging Recycling: A Mini-Review

Recent Advancements in Plastic Packaging Recycling: A Mini-Review

Kinetic Modeling of Hydrocracking of Low-Density Polyethylene in a Batch Reactor

Closing the Carbon Loop in the Circular Plastics Economy

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