Determination of the residence-time distribution in industrial dryer for the production of recycled polyester

The study proposes the evaluation of residence-time distribution (RTD) in situ an industrial dryer for production recycled polyester fibers (PES) from colorless polyethylene terephthalate (PET) flakes without interruption production. A disturbance pulse type was employed, which tracer (blue PET flakes) had previously been crystalized and its concentration obtained according to time at outlet. Additionally, analyses intrinsic viscosity crystallization percentage (colorless blue) PES color force were performed. By RTD, mean residence (322.8 min), variance (1305.4 min2), standard deviation (36.1 min) relative error (1.5%) when compared theoretical time, indicating absence preferred paths or flake agglomerates equipment. Finally, characterization demonstrated that there no alteration parameters product quality during RTD evaluation, confirming potential application this methodology diagnoses continuous processes.