Pyrolysis of Mixed Plastic Waste

More than 400 million tons of plastic are produced every year, and almost all originates from fossil resources. After use, most plastics are incinerated or landfilled, resulting in significant CO2 emissions and environmental pollution. With growing demand for sustainability, recycling has become increasingly important. Conventional recycling methods fall short of reducing emissions, pollution, and dependence on fossil resources. In these recycling processes, plastic waste is typically melted and reshaped into new products. However, these methods only apply to a small fraction of plastic waste, as most is mixed, too dirty, or heavily contaminated. That is where pyrolysis provides a solution. Pyrolysis is an advanced recycling technology in which plastic waste is heated to high temperatures above the melting point (>400 °C), converting it into a mixture of gases, oil, and solids. Crucially, this process can recycle plastics that currently have no viable recycling route. The oil can be used in the existing petrochemical industry to produce plastics indistinguishable from fossil-based plastics, enabling true circularity. This technology is not without challenges. The oil may be contaminated, and the process is not 100% efficient, so some fossil input remains necessary. This thesis demonstrates the potential of plastic waste pyrolysis to reshape plastic recycling. It systematically investigates challenges in plastic waste pyrolysis and presents processing improvements to enhance the potential of pyrolysis as a recycling method. While pyrolysis is not a complete solution, it clearly presents itself as a part of the solution to make society more sustainable.