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Karin Lindqvist
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Chemical PET recycling creates new products
Plastic becomes new plastic, which becomes new plastic, which becomes new plastic, and on it goes. Using materials in a cycle is important for us to achieve the national environmental and climate goals and the global goals in the 2030 Agenda. The speciality chemicals group Perstorp is now participating in a project for the large-scale chemical recycling of PET packaging. And they see a clear potential in developing and producing new products for their customers.
You rinse them out, collect them and take them to a recycling station. But unfortunately, much of the plastic packaging that we sort is not recyclable. Instead of being reused, it is incinerated. This includes certain PET packaging, such as coloured bottles or meat packaging trays. The quality of plastic is often poor due to contaminants and paints.
The global chemical industry group Perstorp is one of many companies striving to lower their carbon footprint and offer more green and sustainable solutions. Being able to recycle the raw materials is an important part of the work involved in transition. Today, Perstorp’s products are found almost everywhere, as components in plastics, glass, lubricants and much more.
Developing process for chemical recycling
As part of their efforts to become more sustainable, Perstorp is collaborating with RISE to develop a process for the chemical recycling of PET packaging. This is done through the depolymerisation process, which breaks down the long molecular chains in PET into simpler molecules, called monomers (see About section). In Perstorp’s case, PET becomes the chemical BHET, which can be used to make new PET or to develop new products.
“For example, it could become paints, coatings, structural foams, or packaging materials, such as Perstorp’s special PET Akestra, which is used in different types of food packaging,” says Christian Andersson, Process Technology Specialist at Perstorp.
Andersson sees great advantages in using packaging waste for this type of chemical recycling:
“It’s a relatively well-defined raw material that makes it possible to utilise the carbon that was already used to create the packaging. By using that carbon, the need for new fossil carbon is, in turn, reduced. Through depolymerisation, a chemical is created that is well-suited to our and our customers’ value chain.”
Independent LCA studies important
Since 2017, RISE has been working to develop concepts for recycling PET plastic. The goal is to create a system for large-scale recycling. It has been shown that mechanical recycling works poorly, but that depolymerisation produces good results. Above all, the investigated product demonstrates a high level of purity after processing.
The project has been led by Karin Lindqvist, senior researcher at RISE and was funded by RE:Source:
“By using life-cycle assessments, LCA, we work to simulate and optimise the future production of recycled PET based on a monomer that will be environmentally sustainable and beneficial compared to fossil fuel-based raw materials.”
RISE has investigated the environmental benefits of using materials circularly.
The studies have shown that climate impact can be reduced by 55 percent when waste is used as the raw material compared to fossil fuel-derived raw material. But this requires an optimised process to get as many monomeric components as possible, while keeping electricity and water consumption at low levels.
Valuable insights for future projects
Christian Andersson at Perstorp was eager to participate in the project because he thinks it clearly combines sustainability work with engineering knowledge. He sees the LCA studies as perhaps the most important aspect of the collaboration with RISE. Getting access to studies carried out by an independent party is invaluable to Perstorp’s continued decision-making process. It is currently being discussed whether it is possible to start production of recycled PET at Perstorp’s facility in Stenungsund.
“Chemical PET recycling on a large scale has so far only been applied to a limited extent,” says Andersson. “RISE is the organisation in Scandinavia with the most experience in research and development. Following and participating in the work from start to finish provides very valuable insights and knowledge for our future process and production development projects.”
Chemical recycling of plastics and textiles
Condensation polymers (for example, what we often see as materials in clothing – polyesters and polyamides, better known as nylon) are long molecules made up of unstable bonds that can be selectively broken down. The process is called depolymerisation and – in the case of PET – releases the monomer bis(2-Hydroxyethyl) terephthalate (BHET), which serves as the building block for new PET plastic. Out of the monomer, new polymers are formed that can be used to spin polyester fibres, for example, which are woven into textiles. The monomer can also be used as a basic chemical in various chemical processes.
Perstorp
Perstorp is a group focused on speciality chemicals with headquarters in Malmö, Sweden. Among other things, they manufacture components for plastics, glass, lubricants, eco-friendly biofuels, and chemicals to preserve the quality and extend the service life of products in the agricultural and food industries. Perstorp has approximately 1,500 employees and a turnover of SEK 10 billion. Owned since 2022 by the Malaysian Petronas Chemical Group.
