Modeling and kinetic analysis for co-pyrolysis of sewage sludge and municipal solid waste under multiple factors

Under the goal of promoting global carbon reduction to achieve sustainable development, solid waste disposal and utilization plays an important role in achieving carbon neutrality. In order to better realize the resources utilization, the multi-component solid waste collaborative disposal needs to seek suitable combination. The collaborative disposal of sewage sludge (SS) and municipal solid waste (MSW) has a good application prospect. In order to comprehensively understand their co-pyrolysis characteristics, this study conducted a series of thermogravimetric experiments. The synergistic and pyrolysis kinetics were investigated. Three kinetic models were used to calculate the activation energy (E alpha), and obtain the main reaction mechanism model. In order to explore the effect of blending ratio, heating rate, pyrolysis temperature, and residence time on co-pyrolysis product distribution, orthogonal experiments were conducted and the results were discussed by intuitive analysis and variance analysis. Artificial neural network, support vector machine, random forest, and multiple nonlinear regression models were established to precisely simulate the pyrolysis products distribution, thus to optimize pyrolysis conditions. The results indicated that the addition of MSW made pyrolysis process more stable, and the addition of SS reduced the E alpha. The main reaction mechanism followed diffusion model. The pyrolysis product distribution was affected the most by pyrolysis temperature. Pyrolysis temperature and residence time showed a certain interaction. Besides, multiple nonlinear regression model showed the optimal prediction accuracy for the co-pyrolysis process. It is hoped that this study can provide comprehensive fundamental knowledge for the collaborative disposal of SS and MSW and help to achieve carbon neutrality.