Alongside proven solutions for mechanical plastics recycling, Coperion realizes plants for chemical plastics recycling. This process converts plastic waste back into high-quality raw materials, potentially making unlimited recycling possible. So far, the process is energy intensive and does not always result in high-quality products. Using catalysts could play an important role in the continued improvement of end product quality and process efficiency.
The University of Utrecht’s research project is dedicated to precisely this challenge. The STS 25 Mc11 twin screw extruder, being installed there to carry out the experiments, processes waste plastic, shredded or compacted, with two co-rotating screws in a closed process section. Together, intensive dispersion and high shear introduce a great deal of mechanical energy into the material. The plastic is energy-efficiently melted – an advantage that is particularly important in chemical recycling. Moreover, the extruder achieves a very high mixing effect with its twin screws. The catalysts being implemented in this research project are distributed absolutely homogeneously throughout the plastic melt and can fully develop their intended effect.
In conventional pyrolytic processes, the hot plastic melt is prepared within the twin screw extruder for the next step in chemical processing: pyrolysis. There, in an oxygen-free environment, the plastic is broken down to its chemical building blocks. The temperature of the pyrolysis can be lowered thanks to the efficient use of catalysts, as Vollmer’s team has shown in preliminary work.
