Grandstand | “Towards a circular plastic economy”

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Plastic waste treated using emerging technologies could recycle between 5 and 15 million additional tons per year by 2030. Ben Owens, Vice President and General Manager Honeywell Sustainable Technology Solutions, discusses the process of UpCycling which could be a response to the management of this waste.

According to a 2020 study conducted by AMI International, plastic waste processed using emerging technologies such as UpCycling could recycle between 5 and 15 million additional tonnes of plastic waste per year by 2030 – nearly 14 million tons of uncompacted plastic waste, enough to fill about 70 American football stadiums.

Plastics play an important role in our society. They are not only cost-effective for a wide range of applications including packaging, textiles, transportation, pharmaceuticals, electronics, appliances and sports, but they also extend shelf life. food, which helps reduce waste. What’s more, compared to heavier glass or metal containers, lightweight plastic packaging can help reduce emissions related to the transport of goods.

However, only 10-15% of plastics are recycled due to inherent limitations in the collection, sorting and recycling processes. Most plastic waste is incinerated or landfilled where it can release microplastics into soil and groundwater. Incinerators, on the other hand, can recover some of the energy content of plastic waste to generate electricity, but they release the carbon as carbon dioxide (CO2) into the atmosphere.

Limits of current recycling techniques

Today, most plastic waste is recycled through mechanical recycling, during which it is washed, chipped, melted and reformed into pellets that can be used to create new products. With each pass through this process, the physical properties of the plastics deteriorate somewhat, which limits them to lesser quality applications, such as the stuffing of jackets or the manufacture of public benches. This degradation in performance is called “downcycling” or “décyclage”. Only certain polymers, colors and formats are suitable for mechanical recycling. Plastics sorting facilities must sift through general waste streams to separate the optimal materials and reject waste fractions such as flexible plastics, polystyrene, and incompatible sizes or colors of rigid polyethylene and polypropylene. These waste plastics will eventually end up in a landfill or incinerator.

In comparison, chemical recycling breaks down plastics at the molecular level, producing a substitute feedstock for use in existing plastics production plants. Some chemical recycling processes generate monomers that can be purified and repolymerized to form the same polymers from which they were derived. These processes lend themselves particularly well to polymers such as PET, commonly used in beverage containers, because they can be easily depolymerized while leaving the monomers intact. However, recycling lower quality mixed plastic waste streams is more difficult and requires processes capable of handling different plastics and non-plastics. Technologies such as pyrolysis are able to meet this need.

Pyrolysis involves subjecting loosely sorted mixed plastic waste to moderate temperature and pressure, in the absence of added oxygen, to break down the plastic waste into hydrocarbon molecules that resemble conventional raw materials from plastic. This recycled polymer feedstock is transformed into a new plastic with the same high quality and high performance properties as plastics made from conventional sources. Low-grade plastic waste streams treated by pyrolysis are not rich enough in terms of formats, polymers or colors to be mechanically recycled. Without such processes, they would end up in landfills or incinerators.

Thus, the recovery of mixed plastic waste by pyrolysis makes it possible to prevent these plastics from reaching the end of their life in landfills or incinerators, while replacing the fossil raw materials that would have been used to manufacture new plastics. Companies specializing in these issues are now considering ways to improve the efficiency of pyrolysis to increase the volume of plastic waste that can be recycled.

How the UpCycling process works

UpCycling’s UpCycling process uses chemical technology honed over decades to pyrolyze plastics under mild conditions, breaking down hard-to-recycle plastics into their building blocks.

Low-quality, colored, flexible, multi-layered, polyolefin or polystyrene-rich plastic waste, which would otherwise be disposed of by incineration or landfill, is broken down by pyrolysis, from large complex polymer molecules, into larger hydrocarbon molecules. simpler and smaller. Once the vapors have been collected, condensed and stripped of traces of contaminants, the liquid product (recycled polymer feedstock) is shipped to a steam cracking plant, where it is converted into plastic precursors that can be used to produce recycled plastic from Superior quality with performance equivalent to products made from fossil sources. For example, through the UpCycling process, a mixture of poorly sorted plastic waste can be recycled into new plastics suitable for food or medical grade applications, not just bench boards or jacket padding.

The UpCycling process was designed with both operational resilience and economic performance in mind. By turning low-value plastics and mixed waste into feedstock for steam cracking, plastics manufacturers are better able to meet their recycled content targets. This results in high demand and high value for the recycled polymer feedstock produced by the UpCycling process. In addition, the latter aims to strike a balance between capital efficiency and raw material availability to meet the mixed plastic waste recovery needs of a typical metropolitan area through a modular design of equipment. Scalable, it can be integrated into a series of existing waste management and petrochemical infrastructures on a global scale.

Moreover, unlike combustion or incineration, UpCycling does not consume oxygen; its main objective is not to burn plastic to produce energy, but to transform recycled plastic into raw material to make new plastics. While combustion transforms the carbon contained in plastics into carbon dioxide released into the atmosphere, the UpCycling process is designed to optimize the amount of carbon from the plastic that ends up in the recycled polymer feedstock, which allows a high level of circularity.

Provide an array of benefits

According to a life cycle analysis carried out in October 2021 and relating to an UpCycling treatment plant in Spain, this process is expected to reduce CO2 equivalent (CO2eq) emissions by more than 50% compared to the same amount. of virgin plastic produced from fossil raw materials. In addition, it should reduce CO2eq emissions by more than 75% compared to a conventional combination of conventional plastic waste treatment processes, such as incineration and landfilling. These CO2eq reductions are among the most significant improvements of any plastic waste pyrolysis technology solution.

Above all, UpCycling helps divert millions of tons of plastic waste from landfills and incinerators, reducing both the global threat of plastic waste leakage and dependence on fossil fuels for the manufacture of plastic.

There is no miracle solution to eliminate plastic waste. UpCycling’s process won’t solve all of the world’s recycling needs, but it’s been designed to work in conjunction with other waste management methods, each of which continues to play to its strengths. This process drives the changes the world needs in plastic waste management and offers the opportunity to create an unprecedented, global circular plastic economy that improves the sustainability of everyday products.

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