From plastic waste to wealth using chemical recycling: A review

Jiang, Jie; Shi, Ke; Zhang, Xiangnan; Yu, Kai; Zhang, Hong; He, Jing; Ju, Yun; Liu, Jilin

doi:10.1016/j.jece.2021.106867

Cited by 158 publications

(112 citation statements)

References 90 publications

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“…Several reviews have addressed back-to-monomer molecular recycling by thermal, chemical, and (bio)catalytic unzipping of polymer chains. [457,459,464,491,[511][512][513][514][515][516][517][518][519][520][521][522][523][524][525][526][527]72,79,80,82] Similarly to polymerization catalysis in industrial polymer manufacturing processes, depolymerization catalysis plays a key role in back-to-monomer molecular recycling. [80,468,491,515,526,528] In contrast to polymers such as polyolefins, acrylics, and vinyl polymers, all of which have hydrolytically stable C-C linkages in their backbones, polycondensation-and polyaddition-based polymers contain ester, amide, urethane, and carbonate groups that enable monomer recovery by hydrolysis and solvolysis.…”

Section: Back-to-monomer 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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Section: Back-to-monomer Molecular Recyclingmentioning

confidence: 99%

Closing the Carbon Loop in the Circular Plastics Economy

Schirmeister

Mülhaupt

2022

Macromol. Rapid Commun.

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“…All these operations reflect the processing of heavy fractions of crude oil. Process solutions in this area are created on the basis of very advanced refining and petrochemical solutions, both in the field of equipment solutions and the catalysts used [47][48][49].…”

Section: Crackingmentioning

confidence: 99%

Recycling of Plastic Waste, with Particular Emphasis on Thermal Methods—Review

Kijo-Kleczkowska

Gnatowski

2022

Energies

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The civilization development requires improvement of technologies and satisfaction of people’s needs on the one side, but on the other one it is directly connected with the increasing production of waste. In this paper, the authors dealt with the second of these aspects, reviewing the recycling of plastic waste, which can be processed without changing its chemical structure (mechanical recycling), and with changing its chemical structure (chemical recycling, of which thermal recycling). Mechanical recycling involves shredding the waste in order to obtain recyclate or regranulate that meets specific quality requirements. Chemical recycling consists of the degradation of the material into low-molecular compounds, and it can take place in the processes of hydrolysis, glycolysis, methanolysis by means of chemical solvents, and during thermal processes of hydrocracking, gasification, pyrolysis, combustion, enabling the recovery of gaseous and liquid hydrocarbons foundings in application as a fuel in the energy and cement-lime industry and enabling the recovery of thermal energy contained in plastics. The paper focuses on thermal methods of plastics recycling that become more important due to legal regulations limiting the landfilling of waste. The authors also took up the properties of plastics and their production in European conditions.

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“…There are currently three common approaches to constructively tackle this issue; even though some may choose to obstruct or negate progress by continuing with the model of business as usual, there are others who are keenly aware of the growing opportunity in this sector and the growing need to prevent further geological spoil. The three common technical approaches are energy reclamation via combustion [ 31 ], mechanical recycling [ 32 ], and chemical recycling through pyrolysis [ 21 , 33 , 34 ]. A life cycle assessment comparing each route [ 35 ] suggests that each process (mechanical vs. chemical recycling) has different pollution levels and that chemical recycling is less polluting compared to present-day mechanical recycling.…”

Section: Process Selectionmentioning

confidence: 99%

The Mechanics of Forming Ideal Polymer–Solvent Combinations for Open-Loop Chemical Recycling of Solvents and Plastics

Tsampanakis

White

2021

Polymers

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The inherent value and use of hydrocarbons from waste plastics and solvents can be extended through open-loop chemical recycling, as this process converts plastic to a range of non-plastic materials. This process is enhanced by first creating plastic–solvent combinations from multiple sources, which then are streamlined through a single process stream. We report on the relevant mechanics for streamlining industrially relevant polymers such as polystyrene (PS), polypropylene (PP), high-density polyethylene (HDPE), and acrylonitrile butadiene styrene (ABS) into chemical slurries mixed with various organic solvents such as toluene, xylene, and cyclohexane. The miscibility of the polymer feedstock within the solvent was evaluated using the Relative Energy Difference method, and the dissolution process was evaluated using the “Molecular theories in a continuum framework” model. These models were used to design a batch process yielding 1 tonne/h slurry by setting appropriate assumptions including constant viscosity of solvents, disentanglement-controlled dissolution mechanism, and linear increase in the dissolved polymer’s mass fraction over time. Solvent selection was found to be the most critical parameter for the dissolution process. The characteristics of the ideal solvent are high affinity to the desired polymer and low viscosity. This work serves as a universal technical guideline for the open-loop chemical recycling of plastics, avoiding the growth of waste plastic by utilising them as a carbon feedstock towards a circular economy framework.

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From plastic waste to wealth using chemical recycling: A review

Cited by 158 publications

References 90 publications

Closing the Carbon Loop in the Circular Plastics Economy

Closing the Carbon Loop in the Circular Plastics Economy

Recycling of Plastic Waste, with Particular Emphasis on Thermal Methods—Review

The Mechanics of Forming Ideal Polymer–Solvent Combinations for Open-Loop Chemical Recycling of Solvents and Plastics

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