An Integrated Kinetic Modeling Framework for Copyrolysis of Biomass and Plastic Waste

Area of Science:

• Chemical Engineering
• Thermodynamics
• Reaction Kinetics

Background:

• Pyrolytic processes involve complex solid feedstock properties and reaction pathways, making kinetic modeling challenging.
• Existing models often struggle to accurately predict product yields due to limitations in feedstock data and reaction mechanisms.

Purpose of the Study:

• To develop a systematic, three-module kinetic modeling framework for pyrolytic processes.
• To simulate the copyrolysis of red oak wood and polyethylene terephthalate (PET) and accurately predict solid conversion and product yields.

Main Methods:

• Developed a parallel reaction mechanism, initially using Friedman method and least-squares optimization with thermogravimetric analysis (TGA) data.
• Retrained the model with vertical-tube reactor data, incorporating Sequential Least Squares Programming (SLSQP) for bioproduct mass distribution.
• Integrated tar decomposition reactions with the parallel mechanism, using Particle Swarm Optimization (PSO) for parameter determination.

Main Results:

• The initial model, based on TGA data, could predict solid conversion but not product yields.
• The second module model showed inaccuracies at higher temperatures (700 °C), necessitating the inclusion of secondary reactions.
• The final combined model accurately simulated copyrolysis and validated experimental data (500-700 °C) for both solid conversion and product generation.

Conclusions:

• A robust kinetic model for copyrolysis was successfully developed by combining parallel and tar decomposition reaction mechanisms.
• The proposed methodology for identifying reaction mechanisms and kinetic parameters is valuable for modeling other complex pyrolytic systems.
• Accurate prediction of solid conversion and product yields is achievable through systematic model refinement and integration of secondary reactions.