Editor’s Comment

Undeniable chemistry

Photo credit: Arto Alanenpää
Steven Pacitti – editor

At a recent briefing between stakeholders and policy makers in Brussels, Belgium, EU environment commissioner Karmenu Vella admitted that the EC is eager to learn more about chemical recycling. As the plastics packaging industry transitions from a linear to a circular economy, how big a role could chemical recycling play? Possibly a significant one, if the abundance of chemical recycling headlines in recent weeks is anything to go by.

So, in honour of the chemistry classes from my school days, this month’s Editor’s commentary comes to you in the form of a chemistry experiment.

Introduction

Whether you describe it using metaphorical language such as the breaking apart of LEGO bricks or the deconstruction of a classic food recipe in order to look adventurous in the kitchen, chemical recycling has been turning plastics into fuel for decades, but it is now the focus of intense innovation as industry seeks to tackle the recycling of mixed plastics waste streams.

Chemical recycling is not a one-size-fits-all solution, though, as there is more than one way to cook an egg! But regardless of whether it’s poached, fried, scrambled or boiled, the question many people are asking is: could chemical recycling be the answer to the so-called single-use plastics problem?

Method

There are essentially four methods of chemical recycling. The first is depolymerisation, which turns materials such as PET back into monomers, and these can then be re-polymerised into new PET-based products.

The second method is solvolysis, which is used to break down specific plastics, such as expanded polystyrene (EPS), into monomers with the aid of solvents.

Pyrolysis is the third method, which reduces mixed plastics into oil that can be further refined for new plastics production.

The final method is gasification. Here, unsorted, uncleaned plastics waste is converted into syngas and then used as building blocks for new polymers.

Hypothesis

Within a circular economy utopia, if you are not recycled or recyclable, then you are nothing! With that in mind, the seemingly mad scramble (and we’re not cracking eggs this time!) to develop chemical recycling solutions makes perfect sense.

Eastman followed its March launch of an ‘advanced’ circular recycling technology, which breaks down polyester waste that cannot be recycled by current mechanical methods into basic polymer building blocks, by a month later introducing carbon renewal technology, which can recycle non-polyester plastics and mixed plastics, including flexible films.

Likewise, ReNew ELP is pushing hard to bring a new technology to the UK that recycles end-of-life plastics into valuable oils and petrochemicals, but managing director Richard Daley throws a cautionary spoon at the eggshell by claiming that government support will be vital to enabling the economic and environmental benefits of these technologies to be realised.

While nobody would argue that conversion of waste plastics into hydrocarbons that can be used to produce new plastics is anything other than recycling, the current legislative framework, he says, lacks a clear and transparent definition. This lack of clarity is a cause of major uncertainty for investors and supply chain partners, delaying or putting projects at risk.

Daley wants chemical recycling to be recognised as a recycling process, not least in the UK, because it will reduce the current dependency on landfill and incineration. Will governments make that step change?   

From a personal perspective, any technology that recovers the base chemical constituents of a valuable material like plastics, can only be a good thing. It certainly expands on the concept of the plastics circular economy.

Results

It is telling that just last month chemical recycling firm Plastic Energy signed an agreement to build five plants in Indonesia to help the country meet its target of reducing marine plastics waste by 70 per cent by 2025.

The technology converts end-of-life plastics into hydrocarbon oil called Tacoil, which can either be used as feedstock for virgin-like recycled plastics, or as low-carbon fuel.

ReNew’s technology uses water as ‘the agent of change’ to convert waste plastics feedstocks into synthetic crude oil, chemicals and waxes. Using Australian firm Licella’s Catalytic Hydrothermal Reactor (Cat-HTR), the process accepts everything from rigid pots and trays to lightweight multilayer films. Work on a first commercial plant should start this year.

Meanwhile, US firm Agilyx is doing something rather interesting at the moment: dispelling the myth that Styrofoam is unrecyclable. Last year the company opened a polystyrene-to-styrene oil chemical recycling plant in Oregon.

Likewise, INEOS Styrolution has completed the first successful test runs producing virgin polystyrene from previously depolymerised material. The experiments took place at the company’s Antwerp site in Belgium.

This year also saw the launch of PET bottles made from 100 per cent purified terephthalic acid (rPTA) through the enzymatic bio-recycling of plastics waste. Designed by French firm Carbios, depolymerisation takes place due to the combination of polymers and enzymes.

More recently, DuPont Teijin Films introduced its LuxCR depolymerisation process, which can be used to produce BOPET films for markets including food packaging. The process uses recovered PET flake as feedstock.

At the same time, a chemical process called Newcycling continues to make progress, having been launched in 2017 by APK Aluminium and Kunststoffe AG. Targeting flexible films used in the food industry, the technology separates polyethylene from the polyamide with a centrifuge, and solvent is removed during the subsequent cleaning. This leaves plastics in its purest form, ready for reuse.

Conclusion

Although mechanical recycling will continue to be the preferred option for post-consumer and post-industrial plastics, it is not realistic – or indeed possible – to have an all-encompassing mechanical approach to packaging. As such, chemical recycling provides an attractive proposition. Is the target to take the materials all the way back to monomers, or is an intermediate stage preferable? The more complex the separation, the more energy intensive and costly it is likely to be.

While chemical recycling should not be seen as an excuse to disregard the ‘design for recycling’ mantra, it could certainly be a complementary channel for hard-to-recycle materials. But it will need help, as ReNew’s Richard Daley highlighted.

There will be inevitable challenges. Gasification works on a larger scale than pyrolysis, which means that it is easier to establish pilot facilities for the latter. However, there has to be an element of separation of non-organic materials before pyrolysis is possible.

BASF has proven the case for pyrolysis, having showcased at the end of last year mozzarella packaging made from polymers generated using pyrolysed plastics waste. There is reason to believe that ChemCycling could indeed become a commercial reality, when the economics are right.

Industry is definitely not walking on eggshells when it comes to chemical recycling, but it has to tread carefully, as stepping on one of those LEGO blocks is certainly not recommended. Innovators will need help from above, but there is a case for chemical recycling, absolutely.