Toward a Circular Economy in Plastics: Advanced Numerical Modelling and Positron Imaging of Waste Plastic Recycling Systems

This research program employs advanced positron emission particle tracking (PEPT) instrumentation and algorithms to resolve three-dimensional tracer trajectories, instantaneous velocity fields, circulation patterns, residence time distributions and mesoscale structures in opaque gas-solid fluidized beds across laboratory and large (multi-metre) scales anddiverse configurations; it quantifies how distributor/nozzle design, gas injection strategy and scale influence solids mixing, bubble dynamics, back-mixing and flow non-uniformities, while novel post-processing methods enhance multi-particle localization accuracy and data density for rigorous benchmarking of CFD and coarse-grained CFD-DEM hydrodynamic, mixing and heat/mass transfer predictions. The goal of the project is to provide new, underpinning knowledge for the development of improved, fluidised-bed-based chemical recycling technologies that divert mixed and contaminated plastic streams from landfill or incineration and advance circular resource and emissions objectives.