Pictured above, from left: Purdue University’s Nien-Hwa Linda Wang, P&G’s John Layman,
AmSty’s Jon Timbers and Robert Render of Ravago Recycling Group, who served as moderator for the session
A session at the 2018 Re|focus Sustainability & Recycling Summit, which the Washington-based Plastics Industry Association hosted in conjunction with NPE 2018 in Orlando May 8-10, examined the potential of chemical-based plastics recycling. Speakers looked two technologies that are in the process of scaling up, while a Purdue professor shared the results of the technologies she has been working with in her lab.
John Layman, R&D section head and chief technologist at Cincinnati-based Procter & Gamble (P&G), said the company views polymers as having a great deal of value, adding, “We should reuse them as much as we can.”
While Layman said mechanical recycling has limitations, he said he did not mean to be critical of the process, saying it “plays a critical role.”
The limitations associated with mechanical recycling of polypropylene (PP) currently keep P&G from increasing its use of recycled PP. Because most recycled PP is black or gray and very little clear postconsumer resin (PCR) is available on the market, coloring it can be an issue. Additionally, he said, the material can be “stinky” and contaminated with “toxic chemicals.”
These issues and P&G’s desire to use more recycled PP in its packaging led the company to develop a solvent-based recycling process for the material. (See “Game-changing innovation” for more information on PureCycle technology.) According to P&G, which developed the technology, and PureCycle Technologies, the Ohio-based company that has licensed the technology to commercialize it, the process removes color and odor, producing a recycled flake with “virgin-like quality.”
The P&G-developed technology uses a solvent to perform the extraction and dissolution, Layman said, adding the insoluble material is filtered out so only the soluble PP remains. While he declined to mention the solvent by name, Layman did say it was commonly found in shaving cream. The need for a single solvent improves the cost-effectiveness of the process, he added.
P&G and PureCycle Technologies are not the only companies commercializing a chemical recycling process for plastics. Tigard, Oregon-based Agilyx has broken ground on what it calls the first commercial-scale closed-loop chemical recycling process for polystyrene in the world.
The Tigard plant will recycle up to 10 tons per day of polystyrene scrap to produce high-quality styrene oil that will be used by styrene manufacturers AmSty and INEOS Styrolution for processing for manufacturing consumer goods.
Jon Timbers, senior manager of sustainability and innovation, AmSty, headquartered in The Woodlands, Texas, presented during the session. He said his company makes styrene and polystyrene and has eight U.S. locations. AmSty has 20 percent of the North American styrene market and 30 percent of the polystyrene market, Timbers added.
He said chemical recycling of plastics complements existing recycling technologies, through which important performance characteristics can be lost after a single use. “Existing recycling technologies can find it difficult to restore those properties,” he said.
In addition to being able to retain the properties of virgin plastics, Timbers said, the main advantage of chemical recycling is that it puts recycled material on the same place in the cost curve as virgin material.
The panel also included Nien-Hwa Linda Wang, a professor of chemical engineering at Indiana’s Purdue University. Wang and her team developed a mixed-solvent extraction process to recover polycarbonates and a simulated moving bed process to recover flame retardants from scrap polymers.
She began her presentation by sharing figures on plastic waste generation, saying 350 million tons of plastic waste were generated in 2015 out of roughly 400 million tons of the plastic produced that year. Of that waste, she said 90 percent went to landfills, while 3 percent migrated to the oceans. According to Wang, less than 10 percent of the end-of-life plastic generated was recycled.
Using her team’s selective extraction and chromatography separation technologies, Wang said “pristine” polymers could be recovered from sorted plastic from e-scrap at a cost that ranged from 3 cents to 5 cents per kilogram. Her team recovered polycarbonate, flame retardants, acrylonitrile butadiene styrene (ABS) and styrene acrylonitrile (SAN) from engineered plastics used in e-scrap using these technologies.
Wang said the production costs associated with her team’s technologies were an “order of magnitude less” than batch processing, adding that the combination of the two approaches “can respond to market needs.”
Wang and her team are seeking feedback, collaboration and commercialization partners, she said. She can be contacted at firstname.lastname@example.org, while Will Buchanan at the Purdue Research Foundation can be contacted at email@example.com.