Chemical recycling gives new life to worthless plastic waste

2020-08-21

Successful testing has shown that contaminated plastics, such as worn out industrial straps and colored laminate packaging, can be chemically recycled into pure monomer. The pure monomer produced can in turn be re-polymerized into virgin quality polyester for things like new textiles. By complementing the depolymerization recycling process with additional methods for removing pollution, the pilot project funded by RE:source has given new life to waste streams previously considered worthless. As there is currently no system or large-scale technology to handle plastic waste flows, upcycling of hard-to-treat plastics is a significant step forward, says Hanna Skoog, Program Director for Circular Economy, Axfoundation.

Contaminated plastics, such as worn out industrial straps and colored laminate packaging, can be chemically recycled into pure monomer.

Contaminated plastics, such as worn out industrial straps and colored laminate packaging, can be chemically recycled into pure monomer.

The use of polyethylene terephthalate (PET) polyester has increased tremendously in recent decades. In terms of volume, it is today the fourth most widely used plastic in the world. Its popularity resides in its mechanical properties, machinability and low price, which makes PET suitable for everything from textile fibers and bottles to film. There are, however, also downsides to using PET. Although PET bottles are widely recycled (84% in Sweden), today there is no system for the large-scale recycling of textile fibers and other uses of PET. Instead, most of the plastic is burnt, at best for energy recovery. The project “Chemically recycled PET/polyester as raw material for additive and new polymer” brought together partners from various industries and parts of the value chain to tackle the problem.

Seizing the market potential of contaminated waste streams

“As part of this project, we have taken plastic streams that are today considered useless, due to various impurities, and we have proven that they can be upcycled. There is future market potential for waste streams of contaminated polyester products from industry, production waste, food packaging with laminates and labels, textile waste with difficult staining.” – Hanna Skoog, Program Director Circular Economy, Axfoundation

Internationally, several chemical recycling initiatives using depolymerization are underway, yet many of them handle only specific, usually very pure streams of waste, such as PET bottles. This project has instead tested a process that can handle several streams of real waste as well as contaminated materials used in industry. According to Karin Lindqvist, project manager at RISE, an important success of the project is that whole packaging, including cover film, glue, labels and paint, has been proven to be recyclable.

“Different methods have been used to remove contaminants such as color from plastic waste. We have successfully enhanced the existing process with decolorization by extraction, activated carbon or filtration. In the end, we produced pure monomer.” – Karin Lindqvist, Project Manager, RISE

72% smaller climate footprint for recycled polyester

According to the project’s final report, it is neither economically nor environmentally justifiable to continue letting the material value of contaminated waste streams go up in smoke through incineration or end up in landfills. There are climate and business benefits to be made if the waste flows are used in a circular way. Among other things, the process developed promises to significantly lower greenhouse gas emissions compared to producing PET from virgin raw materials. A lifecycle analysis calculated for industrial-scale production suggests that emissions can be reduced from 1.8kg of Co2e/kg of product when using fossil raw materials to 0.5kg of Co2e.

The project has also evaluated the possibility of using the recycled raw materials to spin new polyester fibers and weave textiles, with properties equivalent to newly manufactured ones. In the test, fabric was produced with 50% of the recycled polyester from industrial waste, which is an example of upcycling. Results showed that repolymerized PET may also be used in packaging and other applications.

From testing to industrial scale

There is now a strong interest among the project partners to push the development further as testing offered potential solutions to two practical problems: how we can loop today’s worthless plastics, and how we can ease the demand for virgin raw materials. Further development of the process is needed, as well as testing on a larger scale. The project partners are currently discussing the next steps, which will include mapping waste streams of polyester in Sweden to evaluate the need for an industrial-scale depolymerization plant, the level of purity required, and the need for pre-treatment, necessary logistics and costs.

“The development of a facility for the depolymerization of PET and polyester in Sweden within a five-year period is a reachable target. But both commercial driving forces and policy instruments are needed for this to happen.” – Karin Lindqvist, RISE

“The successful testing has provided us with new avenues of exploration and we hope to be able to take the results to the next step with a demo project which aims to test the solution on a larger industrial scale through our initiative From waste to fashion.” – Hanna Skoog, Axfoundation

Broad cooperation in consortium

A wide range of partners from different industries and parts of the value chain were able to contribute materials, requirements, knowledge, processes and testing to drive the project. The role of Axfoundation has been to bridge research and business and contribute to concrete challenges that companies face.

The project has been financed by research program RE:source with support from Vinnova, Formas and Energimyndigheten. The project has been led by Karin Lindqvist at research institute RISE and the project partners have been Axel Johnson International, Axfoundation, Axfood, Diab Group, Didriksons, FOV Fabrics, Förpacknings- och Tidningsinsamlingen, National Högsäter/Sweden, Nexam Chemicals, Perstorp AB, Recyctec AB, Sporda sqNonwoven, and Tarkett AB.

Projects within Circular Economy