Food Waste Devolatilization Kinetics with Demonstration of Its Implementation in Computational Modeling of a Fluidized Bed Pyrolysis Reactor

Abstract

This study presents the derivation of a kinetic model for the devolatilization of post-consumption food waste using thermogravimetric analysis (TGA). The derived model was implemented in an Eulerian-Eulerian Computational Fluid Dynamics (CFD) framework to simulate pyrolysis in a fluidized bed reactor operating at 550 °C. Due to the heterogeneity and complexity of food waste composition, the reaction function and devolatilization kinetics were identified using a staged decomposition approach. As determined by TGA, these stages correspond to the decomposition of protein, cellulose, and hemicellulose approximately between 270 and 300 °C, and the decomposition of lipids approximately between 350 and 400 °C. The activation energy, obtained using three different model-free iso-conversional methods, was consistent, with an average value of \({E}_{a}\) = 219.23 kJ/mol. The pyrolysis reaction was found to follow an order-based model, with the master plot method yielding an average reaction order of \(n\) = 10.3 and an Arrhenius frequency factor of \(A\) = 1.16 × 10¹⁹ [(kmol/m³)¹⁻ⁿ/s]. The predicted distribution of pyrolysis products, validated against experimental data, highlights the robustness of the proposed analysis and its computational implementation. This methodology provides a strong foundation for further development and adaptation to simulate the pyrolysis of food waste and other diverse feedstocks, broadening its applicability to various types of biomass.