The present study addresses the possibility of using a frequency-controllable microwave source, that is, a solid-state microwave generator, to rapidly and efficiently heat PET. Based on dielectric properties measurement of PET, numerical simulation has been used to model dedicated microwave applicators, suitable for the rapid reheating of PET granules or preforms. Numerical simulation, validated by experimental activity, demonstrates that using the proper frequency change as PET is being processed allows to maximize heating efficiency or homogeneity. Two examples of microwave applicators, one for small-scale and the other for large-scale production are presented, specially addressing the effect of using different metals for the modeling and construction of the microwave cavity.
https://onlinelibrary.wiley.com/doi/10.1002/masy.202000204