The group at Chalmers University of Technology, says the process can break down any plastic waste to a molecular level and the resulting gases can then be transformed back into new plastics – of the same quality as the original.
According to the group, the new process could “transform today's plastic factories into recycling refineries, within the framework of their existing infrastructure”.
Henrik Thunman, the group's leader and professor of energy technology at Chalmers University, said the resilience of plastic was an asset. “The fact that it does not degrade makes it possible for circular usage, creating a true value for used plastic, and therefore an economic impetus to collect it.
“We should not forget that plastic is a fantastic material – it gives us products that we could otherwise only dream of. The problem is that it is manufactured at such a low cost, that it has been cheaper to produce new plastics from oil and fossil gas than from reusing plastic waste,” he said.
The team said that through finding the right temperature – around 850 degrees Celsius – and the right heating rate and residence time, it had been able to turn 200kg of plastic waste an hour into a useful gas mixture. This can then be recycled at the molecular level to become new plastic materials of virgin quality.
The team said it was now moving on from the initial feasibility trials to focusing on developing a more detailed understanding.
“This knowledge is needed to scale up the process from a few tonnes of plastic a day, to hundreds of tonnes.That is when it becomes commercially interesting,” said Thunman.
The experiments were carried out at the Chalmers Power Central facility in Gothenburg and the research results were published in the journal Sustainable Materials and Technologies last week.
If made commercially viable, the technology could be a major boost to the UK’s waste industry.
Since China banned imports of most plastic waste in 2018, the sector has warned that the UK is facing a major strain on its domestic incineration and landfill capacity.
In May, this was further compounded when the UN passed an amendment to the Basel Convention, meaning that the UK will no longer be able to export mixed plastics to some countries without first receiving written consent.
The legislation is aimed at halting a huge influx of contaminated and mixed plastic wastes, which are being dumped in developing countries, particularly in South East Asia.