University of Amsterdam Unveils Breakthrough in Plastic Recycling with Pilot Plant for Solvothermal Liquefaction

Researchers at the University of Amsterdam (UvA) have advanced a novel approach to recycling mixed plastics waste, marking a significant step toward a circular economy. The team, led by Associate Professor Dr. Shiju Raveendran at the Van ‘t Hoff Institute for Molecular Sciences, has developed a process called Solvothermal Liquefaction (STL), which transforms mixed plastic waste into oil using solvent, heat, catalysts, and pressure. A pilot plant, designed to scale this technology, is set to begin operations in Spain this summer, processing real municipal plastic waste.

How STL Works: A New Approach to Plastic Recycling

The STL process, part of the European PLASTICE project, addresses the challenge of recycling mixed plastics, which currently require extensive sorting before disposal. Unlike traditional methods that separate plastics by type, STL simultaneously breaks down all plastic materials into oil, gas, and char. Laboratory experiments have demonstrated that the process yields three products within 30 minutes of reaction time, with the oil capable of producing new, virgin plastics. This closed-loop system aims to reduce reliance on fossil fuels and minimize plastic waste sent to landfills or incinerators.

“We have gained a deep insight into the process and are confident that it merits scaling up to industrially relevant volumes,” said Dr. Raveendran. “This pilot plant is a crucial step toward transforming research into real-world solutions.”

Technical Details of the Pilot Plant

The pilot reactor system, co-developed with an Indian engineering partner, features a 25-liter reactor vessel, storage tanks, and integrated safety systems. It is designed as a transportable skid-mounted unit, with two connected ‘skids’ measuring approximately 3 x 1.5 x 4 m and 2.8 x 1.1 x 1.7 m. The system underwent a Factory Acceptance Test in April, with comprehensive safety and process assessments conducted during development. Bureau Veritas approved the engineering designs, ensuring compliance with industrial standards.

The unit will be deployed at the site of PLASTICE partner COGERSA, a public waste management company in Spain’s Asturias region. Researchers will evaluate its performance on “real-life” plastic waste streams, aiming to identify and address challenges not encountered in laboratory settings.

Challenges and Opportunities in Scaling Up

Translating academic research into industrial applications presents unique challenges, including regulatory approvals, safety assessments, and collaboration with engineering partners. Dr. Raveendran emphasized the importance of multidisciplinary teamwork, noting that the project has provided valuable experience for young researchers in navigating industrial complexities. “This is exactly what makes the work meaningful: transforming research into real-world solutions,” he said.

The project, funded by a €19.8 million European PLASTICE initiative, received over €1.5 million in grants for the STL process. Laboratory research included kinetic studies, computational fluid dynamics (CFD) modeling, and techno-economic analyses, with results published in leading international journals.

Why This Matters: The Future of Plastic Waste Management

Global plastic waste has reached alarming levels, with over 400 million tons produced annually. Current recycling rates remain low, as mixed plastics are often non-recyclable using conventional methods. The STL technology offers a scalable solution, potentially reducing the environmental impact of plastic waste while creating value from what is currently considered unusable. If successful, the pilot plant could pave the way for widespread adoption of chemical recycling technologies, supporting the EU’s goals for a circular economy.

As the pilot plant prepares for deployment, the UvA team remains focused on refining the process and demonstrating its viability for industrial use. “We will certainly encounter challenges we could not fully foresee,” Dr. Raveendran acknowledged. “But that is precisely the purpose of this scale-up phase—to move the technology toward genuine industrial relevance.”