When plastics are recycled chemically instead of mechanically, the material becomes truly circular. A unique concept for a plastics recycling refinery has been developed in Stenungsund. With the proper investments, it might be a new Swedish export solution in the making.
”Stenungsund is home to Sweden’s largest chemical industry complex. The companies that established business there in the 1960s have had an exciting journey, full of challenges such as the industrial globalization and a growing need to streamline the production processes. The field of sustainable development is no exception. Lately, the environmental impact of plastics has been in the spotlight, with debates raging about littering, chemical additives and the microplastic pollution discovered in the world’s oceans. It all boils down to the role of plastics in a sustainable society”, says Elin Hermansson, Project Manager of Hållbar Kemi 2030 in Stenungsund (Sustainable Chemistry 2030).
The sustainable chemistry vision: Hållbar Kemi 2030
Plastics play a very important role in society, and the material is used in countless applications around the world. It is both light and strong, and offers economical advantages over other materials. In Sweden, about 30 percent of the plastics is recycled mechanically, and the rest is incinerated for energy recycling. The situation is less promising in countries with underdeveloped recovery and recycling systems; large amounts of plastics end up in landfills or as litter. Prohibiting the use of plastics is hardly a viable solution; replacing plastics with other materials would cause the volume of waste to quadruple, and carbon dioxide emissions would skyrocket by 60 percent.
”We have to improve the recycling efficency, and build a circular economy that includes plastics. There is a planned facility in Rotterdam to turn plastics into chemical products, and one in operation in Canada. But there are no examples yet of feedstock recycling, where plastic waste is degraded into monomers and recycled into new plastics. That means that a Plastics Recycling Refinery in Sweden would be a first decisive step towards a solution to the plastics issue”, Elin Hermansson says.
In Stenungsund, chemical companies AGA, AkzoNobel, Borealis, INOVYN and Perstorp have formulated the vision Hållbar Kemi 2030 (Sustainable Chemistry) as a joint effort. The vision includes replacing fossil-based plastics with bio-based or recovered materials, which can be recycled chemically in the Plastics Recycling Refinery. Such a project would require substantial investments in the development of new technologies, but it would give Sweden the opportunity to find a circular solution to the plastic dilemma.
Chemical recycling of plastics
Mechanical recycling of plastics is an established process employed around the globe to re-melt and re-process the material into new products. The method has several limitations, however: the recyclates do not achieve the quality of virgin material plastics, and the technical properties deteriorate with each cycle. Furthermore, it can only be used on certain kinds of plastics, separated into individual polymer streams.
Chemical recycling is an entirely different approach, where the polymers are degraded chemically into synthesis gas, which in turn is repolymerized into new plastics. The technology is based on high-temperature thermal decomposition such as gasification or pyrolysis. The recycled plastics can be used in conjunction with forest biomass to increase volume and efficiency, making it possible to mix both recycled and renewable feedstocks in the same facility.
”In Stenungsund, we have developed a concept for what we call a Plastics Recycling Refinery. It is a facility where both recycled plastics and biomass can be used as feedstock to make new products. According to our feasibility studies, it has huge potential to reduce the fossil carbon dioxide emissions. More studies are needed to verify how it should be implemented, with regard to things like technology, business models and incentives”, Elin Hermansson says.
Research on the construction of a Plastics Recycling Refinery is conducted at Chalmers University of Technology. One of the pilot studies has been performed on the “Chalmers gasifier”, where plastics are degraded chemically to create building blocks for new high-quality materials. In the process, a catalytic converter separates the plastics into its constituents at a temperature of 800 °C. The project has tested gasification of recycled plastics from the Stenungssund chemical companies mixed with forest residues from Södra. Waste from STENA:s car recycling has also been ground and tested as feedstock.
”A Plastics Recycling Refinery is very much in line with the sustainable chemistry 2030 vision, and it could be a new Swedish flagship solution. For such a facility to work, recycled raw materials must be more readily accepted. It has to get access to plastic waste. It would also require investments and research funding, and discussions about mass balance standards. Economic considerations are central, of course. Ultimately, somebody has to decide that keeping the molecules in circulation instead of letting them burn or drift away into nature it something that it is worth paying for”, Elin Hermansson concludes.
Hållbar Kemi 2030 is one of the contributing parties to the Polyci project, which aims to map all pyrolysis and gasification plants currently in operation around the world and establish the best available technology (BAT). This project could be useful for deciding which processes to include in a Plastics Recycling Refinery in Stenungsund. The project is a University of Borås initiative, supported by RE:Source.
The article was published in December 2017.