Co-combustion of sewage sludge with corn stalk based on TG-MS and TG-DSC: gas products, interaction mechanisms, and kinetic behavior

Rapid urbanization has led to the generation and accumulation of large quantities of sewage sludge, threatening the ecological environment on which mankind depends. Incineration can achieve sewage sludge minimization and energy recovery. In this study, the co-combustion behavior and gas product emission characteristics of sewage sludge and corn stalk were analyzed. The results showed that corn stalk increased the combustion rate of sewage sludge, and its co-combustion performance, flammability and combustion performance were significantly improved. The main influencing factors at each stage were derived by factor analysis. The gaseous products of the co-combustion process were examined by mass spectrometry analyzer, and it was found that co-combustion of sewage sludge with 30% corn stalk could reduce NOx and SO2 emissions by 82.94% and 55.73%, respectively. In addition, the Kissinger-Akahira-Sunose and Flynn-Wall-Ozawa methods were used to calculate the apparent reaction activation energy. The fuel blended with 30% corn stalk had the lowest average activation energy (131.17 kJ/mol) and the strongest synergistic effect. The results of this study may provide new ideas for the synergistic combustion of sewage sludge with corn stalk.