Modeling kinetics and transport phenomena during multi-stage tire wastes pyrolysis using Comsol®

Area of Science:

• Chemical Engineering
• Materials Science

Background:

• Pyrolysis of used tires is a complex process with potential for energy recovery.
• Understanding mass and heat transfer is crucial for optimizing pyrolysis reactor design and operation.

Purpose of the Study:

• To develop a model predicting mass and heat loss profiles during used tire pyrolysis.
• To analyze the impact of reaction kinetics and thermal balances on the process.
• To investigate the role of exothermic reactions and particle size on energy efficiency.

Main Methods:

• Mathematical modeling of thermal balances and reaction kinetics.
• Resolution of differential equations to simulate heat variation within a fixed bed reactor.
• Comparison of theoretical modeling results with experimental data and literature findings.

Main Results:

• The model accurately predicts heat and mass loss profiles, showing satisfactory agreement with experimental results.
• Significant exothermic reactions were identified, with center particle exothermic heat exceeding 1500 kJ/kg.
• Smaller particle sizes enhance heat transfer and reduce process time but can increase endothermic reaction energy consumption.

Conclusions:

• The developed model provides a reliable tool for predicting used tire pyrolysis behavior.
• Exothermic reactions offer significant economic and energetic benefits.
• Optimizing particle size is key to balancing process efficiency and energy consumption.