Non-isothermal pyrolysis mechanisms of municipal sludge extracts: Experimental and ReaxFF molecular dynamic study

Abstract

The distinctive fuel properties inherent in the municipal sludge extract signify its substantial potential for resourceful application. Experiment and ReaxFF molecular dynamic was utilized to identify major thermal decomposition products and explore the thenon-isothermal pyrolysis mechanism of municipal sludge extracts. TGA and Py-GC/MS results showed that the major products were CO2, C4H6 and C6H6O. As the heating rate increased, the proportions of pyrolysis gas and char within the product decreased, shifting from 35.7% and 9.5% to 22% and 0, respectively. The tar content significant rised by 23.3%. The kinetics parameters showed a direct correlation between the heating rate and the activation energy of the pyrolysis. Specifically, the activation energy for the initial pyrolysis stage elevated from 47 kJ/mol to 210.39 kJ/mol, while that of the rapid pyrolysis stage surged from 170.79 kJ/mol to 242.26 kJ/mol. The primary origins of H2, H2O, and CO stem from the secondary reactions of tar.