Comprehensive Kinetic Study of PET Pyrolysis Using TGA

Area of Science:

• Chemical Engineering
• Polymer Science
• Thermodynamics

Background:

• Polyethylene terephthalate (PET) pyrolysis is a significant process for generating high fuel value.
• Understanding the reaction kinetics is crucial for optimizing PET conversion.

Purpose of the Study:

• To investigate the kinetics of PET pyrolysis.
• To determine the activation energy and reaction mechanism.
• To analyze thermodynamic parameters of the pyrolysis reaction.

Main Methods:

• Thermogravimetric analysis (TGA) was employed at four heating rates (2, 5, 10, 20 K min⁻¹).
• Five model-free kinetic models (Friedman, Flynn-Wall-Qzawa, Kissinger-Akahira-Sunose, Starink, DAEM) were applied.
• The Coats-Redfern model and Criado's master plot were used to determine the reaction mechanism.

Main Results:

• A single kinetic reaction was observed between 650-750 K.
• The average activation energy (E) was determined to be 212 kJ mol⁻¹.
• First-order reaction kinetics best described the PET pyrolysis mechanism.

Conclusions:

• PET pyrolysis proceeds via a first-order reaction mechanism.
• The reaction is endothermic, as indicated by thermodynamic analysis.
• Kinetic data provides insights for optimizing PET conversion processes.