Combustion behavior and activation energy prediction for typical components of municipal solid waste (MSW)

The combustion behavior of municipal solid waste is highly uncertain due to the variability in the content of its major components: food waste, paper, and plastics. Developing a component-based activation energy model is therefore essential. In this study, food waste (vegetables and fruits), paper, and plastics were investigated using thermogravimetric analysis at a heating rate of 5 °C·min^-1. The kinetic mechanisms of individual and co-combustion were determined using the Coats-Redfern method, synergistic effects were evaluated by the differential method, and a quadratic model was developed for four-component activation energy prediction to reduce complex kinetic computation. Results indicated that vegetables combustion followed a diffusion-controlled mechanism, while the other components were reaction-controlled. Plastics exhibited the highest activation energy (172.70 kJ mol^-1), which was 4.33, 1.63, and 5.74 times that of vegetables, paper, and fruits, respectively. The co-combustion of vegetables and plastics demonstrated the strongest synergistic effect, with maximum suppression and promotion rates of 19.41 % and 7.26 %, respectively. The linear variation in the combustion characteristic indices indicated that the co-combustion of fruits and paper exhibited no significant synergistic effect, with maximum suppression and promotion rates of only 0.30 % and 3.77 %, respectively. The developed quadratic model accurately predicted the activation energy (R² = 98.32 %), with a minimum predicted value of 18.83 kJ mol^-1. Plastics consistently exhibited a negative sensitivity to the overall activation energy, and the other components showed sensitivities correlated with their respective ratios. These findings enable the prediction of kinetics parameters for different municipal solid waste components, providing a reliable guide for adjusting energy input (such as air temperature, air volume, and residence time) to achieve complete combustion in applications.