Experimental and numerical simulation of pyrolysis-gasification processes for municipal sludge

In this study, an experimental and numerical simulation platform for municipal sludge pyrolysis-gasification was established to investigate the spatio-temporal evolution of temperature and component concentration fields during the process. A three-dimensional numerical model of the pyrolysis-gasification furnace was developed, incorporating heat transfer, gas flow dynamics, and reaction kinetics. Experimental validation demonstrated strong agreement between simulated and measured axial temperatures, with an average error of 7.76%, confirming the model’s reliability for engineering applications. The study revealed distinct reaction zones within the furnace: an oxidation-reduction zone (1473.15 K) at the bottom driving carbon gasification, a pyrolysis-devolatilization zone (1073.15 K) in the middle facilitating volatile release, and a drying zone (673.15 K) at the top dominated by moisture evaporation. Preheated air (673.15 K, 0.16 m/s) significantly enhanced convective heat transfer, accelerating sludge drying and pyrolysis. Peak pyrolysis gas concentration yields (e.g., CO 2 , CH 4 , H 2 ) occurred within 2–4 s, followed by a decline as dry sludge content diminished. These findings provide critical insights into optimizing sludge pyrolysis-gasification processes for efficient energy recovery and environmental sustainability.