Closed Loop Recycling
Presenter: Ezra Onyango
WSCSD-Kenya
UKUNDA

Background
• The rate of consumer plastic recycling are low
• Due to a lack awareness among stakeholders.
• Plastic recycling is a well-established technology that
contributes to a circular economy.
• New recycling techniques, such as disintegrating plastics in
a solvent to purify and preserve its properties of materials,
will improve plastic waste management practices.
• Polymers can also be depolymerized into monomers in
solution, which can be used to re - create virgin-grade
material.
• The circularity of plastic is limited by current policies and
investments in waste management, detachment, and
recycling.
• Different Loops For Plastics In A Circular Economy are
illustrated in the figure provided

Statement of the Issue
• The development of new plastic materials
adds complexity to the plastic waste market,
• Generally counterproductive to recycling
efforts.
• In the Kenya, recycling failure rates are
already rising,
• Over 12% of post-consumer plastic wastes
from industries and households being
rejected.
• Small volume plastics contaminate PET,
PE, and PP recycling creeks at the end of
their lives,
• Increasing the likelihood that waste will
not be recycled due to poor quality.

CLOSED LOOP RECYLING TECHNOLOGIES
• The technologies fall into three distinct categories.
• Classification is based on the position of their outputs in the
plastics supply chain:
• Purification:
• The use of solvents for removing additives from the
polymers.
• Suitable for polymers
• Depolymerization:
• Breaks down the long hydrocarbon chains in plastics into
shorter hydrocarbon fractions
• Suitable for monnomers
• Feedstock (thermal conversion) recycling:
• Suitable for petrochemicals and refined hydro chemicals
• Breaks down the long hydrocarbon chains in plastics into shorter
hydrocarbon fractions.
• Divided into three categories depending on whether hydrocarbons
are broken down into monomers using chemical, thermal or
catalytic processes
• Gasification (Catalytic process)
• Hydrothermal Treatment (Thermal process)
• Pyrolysis (Chemical process)
Closed loop recycling technologies

Chemical recycling Process
• Divert plastic waste from landfill or incineration.
• Prepare waste polymers for reuse
• Changes the chemical structure of the material.
• Solvent extraction allows for the removal of PVC
from PET,
• It may be necessary to eliminate PLA from PET
waste in the future.
• Solvent-based approaches make recycling more
cost-effective.
• It dissolve and densify polystyrene
Chemical recycling
process

Feedstock Recycling
Purification Recycling
• Enables the production of food grade plastics from
post-consumer waste.
• Enables the further extraction of value from
polymers.
• Targets polymers that have exhausted their
economic potential for mechanical processing.
• Complements mechanical recycling processes.
• Is an alternative to landfill and incineration.
• Is suitable for erstwhile hard-to-recycle plastic
products such as films, multi-layered and laminated
plastics.
• Supplies virgin-quality raw materials to the plastics
supply chain.
Purification Process

Feedstock Recycling Cont,
PET (PolyEthylene Terephthalate) Depolymerization
• PET depolymerization is a very efficient plastic recycling
technology that converts PET (PolyEthylene
Terephthalate) into its basic monomer starting points namely:
• DiMethyl Terephthalate (DMT)
• MonoEthylene Glycol (MEG)
• This process will assist the long term in recycling PET used in
beverage and water bottles and will lead to high recycle
content (25-40%) containers in these applications 3-5 years
out. However, it is currently three times more expensive than
mechanical recycling.
• Also, it is dependent on a low-cost PET flake regrind in
harness with patented formulations currently under
development at major bottle developers like Coca-
Cola and Pepsi.
• Overall PET depolymerization will remain an important but
niche recycling technology long term.

Feedstock Recycling
Pyrolysis Recycling Process
• Pyrolysis is derived from the Greek word, “pyro” which
means heat and “lysis” means to break down.
• It finds use as a recycling technique with mixed plastic
waste streams, totally not adaptable to mechanical
recycling.
• Roughly speaking with economies of scale, every ton of
mixed plastic waste will yield approximately four barrels
of pyrolysis oil.
• Although energy-intensive by nature, pyrolysis fills the
preceding gap best when oil prices are decreasing
• Its distillation streams are targeted towards higher value-
added chemical products,
• Insulates recycling from market price fluctuations.

Pyrolysis
• Pyrolysis is derived from the Greek word, “pyro” which
means heat and “lysis” means to break down.
• It finds use as a recycling technique with mixed plastic
waste streams, totally not adaptable to mechanical
recycling.
• It is energy-intensive by nature.
• Fills the preceding gap in oil production
• Best when oil prices are decreasing
• Its distillation streams are targeted towards higher value-
added chemical products
• Safe from market price fluctuations.
• Every ton of mixed plastic waste will yield approximately
four barrels of pyrolysis oil (economies of scale)
• Polystyrene recycling has a high potential
• Dramatically improve recycling rates.

Solution Suggestion
• Primary recycling techniques such as the use of solvent works particularly well
for high-performance and technical plastics, and should be encouraged.
• Primary mechanical recycling solutions are not available for WEEE plastics
with additives.
• However, adoption of appropriate recycling techniques with the lowest
environmental impact at a high TRL level.
• Closed loop recycling will have a positive environmental impact and contribute
to CO2 reduction.
• Effect of plastic recycling is anticipated to be lowered further in the future
• When solvent recycling technique is combined with green power mixtures,
• since green electricity has fewer environmental consequences than fossil
energy sources.

Solution Suggestion
• Tertiary recycling of monomers through pyrolysis and gasification are the
only option available.
• Enhanced recycling of complex polymers with additives
• Disintegration is pushed to high TRL levels.
• Technologies that recover feedstock or wax from polymers act as
• Bridge between waste streams such as complicated engineering
polymers and thermosets.
• Promote optimum recycling of substantially polluted or mixed streams
of waste.

Suggestion Solution
Solvent Recycling
• Limonene and Switchable-polarity are appropriate
binary solvent systems that can help dissolve
polystyrene.
• Solvent-based recycling techniques effectively
remove brominated flame retardants from plastics.
• By first dissolving the trash and then adding
an extra solvent to selectively precipitate the
polymers
• Higher purity and enhanced sorting improve the
performance of primary recycling techniques
• by removing impurities and enhancing
beneficial environmental consequences.
• As a result, optimum recycling performance is
achieved when pre-treatment (sorting, cleaning) is
tailored to the recycling method.

Suggested Solution
Solvent-based Recycling
• An emerging alternative to dispose of
mixed plastic waste
• An alternative for plastics not
handleable by mechanical recycling.
• Its operational niche is post-industrial,
• Applicable for mixed plastic waste
where contamination challenges are not
relevant.
• Common in post-consumer plastic
waste.
• Primary limitation is a very heavy
dependence on solvent costs that in
turn will limit its market growth.

Conclusion
• None of the preceding major plastic materials recycling technologies will totally dominate in the marketplace.
• Plastic waste and type of waste availability by given global geography will dictate the specific recycling technology
mix.
• For the foreseeable future, a combination of recycling technologies will be in use.
• In any global geographic region, where efficiently sorted, higher quality, and potentially clear plastic waste is available,
it will be best matched by lower-cost mechanical recycling.
• Limited polypropylene and polystyrene plastic waste streams lend themselves to pyrolysis and solvent-based recycling
techniques.
• More specifically, geographies with high volumes of low-cost plastic wastes will gravitate to pyrolysis.
• In the same vein geographic regions where high volume, low quality PET predominates, depolymerization is the answer.
• Only by improving pre-treatment in accordance with the most appropriate recycling process for a polymer can
the environmental performance of recycling be maximized.
• Polymer quality comprising of mixed source, mixed materials is essential
• Polymer influences a technology's overall environmental impact; nevertheless, it has no effect on the
technology's efficiency score.

END
• To explore the newest plastics recycling technologies, I invite you to visit our
waste recycling plant in Ukunda under the project banner “Material Innovations
Supporting Plastics Recycling”.
THANKYOU