Solvent-based plastics recycling still faces hurdles

Dissolution technology using a solvent-based recycling methodology, which comprises part of the larger advanced recycling sector, holds promise but is not without its challenges and criticisms, according to a recent analysis.

In a report titled “Dissolving the plastic waste problem: Can new technologies meet the challenges?,” James Kennedy, a technology analyst with IDTechEx, cites Florida-based PureCycle Technologies Inc. as one company seeking to deploy dissolution technology at scale.

Kennedy says the chemical or advanced recycling market has seen wider investments in technologies such pyrolysis and thermal, chemical and enzymatic depolymerization.

“To a lesser extent, methods such as gasification and hydrothermal liquefaction are also being explored,” he adds.

He indicates, however, that mechanical recycling is the preferred recycling method due to its cost-effectiveness and efficiency, while some chemical recycling methods face increasing scrutiny and restrictions in some regions due to their environmental impact.

In an effort to determine whether dissolution technologies offer a promising alternative, Kennedy and England-based IDTechEx produced a lengthy report they say examines dissolution and the other chemical recycling methods, offering a 10-year forecast on their potential market presence.

“Dissolution involves separating polymer waste using a solvent,” Kennedy writes about the recycling method. “The solvent selectively dissolves the polymer, separating it from contaminants and other nontarget materials. Once dissolved, the solution is purified, and the solvent is removed, leaving behind a nearly pure plastic that can be processed back into granules for reuse in manufacturing.”

IDTechEx indicates the method could be the best one to deal with contaminated or mixed plastics that are challenging to recycle through mechanical means while not breaking the polymers into its constituent molecules or feedstock.

However, the firm adds, the processes are designed with solvents and separation methods for specific plastic types, such as polypropylene (PP), polystyrene (PS) and acrylonitrile butadiene styrene (ABS).

Packaging made with PP has been the focus of PureCycle, which uses dissolution technology developed by Procter & Gamble.

“PureCycle states that its recycled PP can be used in applications where mechanical recycling methods, such as food-grade packaging, would not suffice,” Kennedy writes, calling PureCycle the current leading commercial-scale provider in the dissolution space.

“While dissolution technology holds promise, it is not without its challenges and criticisms," IDTechEx says. "For example, there are questions about long-term circularity as the polymer is likely to degrade over successive cycling.”

The firm says another concern with the dissolution process is the environmental impact of the solvents used.

“These chemicals must be managed carefully to avoid releasing harmful substances into the environment,” IDTechEx writes. “The energy required to heat the solvents and subsequently remove them from the dissolved plastic also adds to the carbon footprint of the process.”

Beyond technology, questions of economic viability also remain. If the cost of running dissolution plants is higher compared with mechanical recycling methods, IDTechEx says the size of this green premium versus other recycling technologies will determine whether dissolution plants can be economically viable.

Despite government and corporate pledges, virgin plastic materials remain a competitive threat.

“Competition from cheaper, virgin plastics can limit the market potential for recycled products,” Kennedy writes.

The report notes that PureCycle is far from alone in the subsector, with companies including Germany-based APK AG, England-based Worn Again and Canada-based Polystyvert working with polyethylene (PE), polyethylene terephthalate (PET) and PS, respectively.

“Dissolution presents a promising technology for addressing the demand for low-carbon, versatile plastic [recycling] solutions," IDTechEx says. "However, several hurdles remain, including technological refinement, commercial scaling and economic challenges.”

More information on the full 250-page IDTechEx report, including how to purchase it, can be found here.