Raw materials producer Covestro is advancing the implementation of its chemical recycling technology to pilot scale, the company has announced in a 16 August statement. Its specific chemolysis process, adapted to polycarbonate, has been shown to be robust at laboratory scale and is now being optimised in further development stages on the way to industrial scale.
In this form of chemical recycling, plastic materials are converted back into monomers, i.e. their individual building blocks, and these monomers can replace primary fossil raw materials in the production of new, high quality polymers.
"As a manufacturer of plastics such as polycarbonate, we naturally have a responsibility in dealing with these important materials, including at the end of their product life,” said Dr. Thorsten Dreier, Covestro's CTO. "We need to use end-of-life plastics as a resource and reuse them as alternative raw materials to close the loop."
Mechanical recycling of polycarbonate is already an important component of Covestro's recycling strategy. The mechanical recycling process is used whenever waste streams are sufficiently pure and the recycled polycarbonate meets the requirements profile of the future application.
Covestro’s chemolysis process works in a complementary way, requiring less pure waste streams and producing a direct precursor of polycarbonate that can be mass-balanced and reused as a raw material for the production of virgin quality polycarbonate without further processing - thus directly closing the polycarbonate cycle.
"Pre-sorted waste streams containing a product content of more than 50 percent polycarbonate can be recycled this way. This has been successfully demonstrated with various polycarbonate-containing plastic waste streams," confirmed Markus Dugal, head of process technology at Covestro.
The next stage of development, the technical implementation of a continuous process, has already started. A pilot plant, currently in the planning stage, will provide the data and experience needed to develop a feasible process for further expansion to industrial scale. The company said it planned to invest ‘millions of euros’ in this over the next few years. The pilot plant will be built in Leverkusen, Germany, where Covestro is headquartered.
Covestro is also exploring other routes for recycling polycarbonate in its research laboratories. These include chemolytic alternatives, recycling with enzymes that break down the plastic, and smart pyrolysis. Promising alternatives can also be tested with the pilot plant.
Covestro is committed to becoming fully circular and is striving to become climate neutral by 2035 (scope 1 and 2). Covestro generated sales of €18 billion in fiscal 2022. At the end of 2022, the company had 50 production sites worldwide and employed approximately 18,000 people (calculated as full-time equivalents).