Effect of lignin on coal slime combustion characteristics and carbon dioxide emission

The escalating total amount of industrial solid waste is increasingly taxing the ecological environment. Cocombustion technology is seen as a potential solution to this problem. This study investigated the interaction mechanism and carbon dioxide emissions during the co-combustion process of coal slime and biomass (lignin) using a programmed heating method. The experimental results reveal that the two sub-reaction models effectively depict the combustion process of coal slime. In the co-combustion process, the comprehensive combustion and ignition performance of the mixed fuels surpasses that of coal slime, but the stability of the combustion flame is reduced. The combustion performance of the mixed fuel is primarily influenced by two common factors. The interaction between lignin and coal slime significantly changes with the variation of mixing ratio and heating rate. The main product in the combustion process of mixed fuels is carbon dioxide. Due to the competition for oxygen among volatile matter, the emission of carbon dioxide is lower than the theoretical value. When the mass percentage of lignin is 70 %, the impact on carbon dioxide is most pronounced. The experimental results of this study provide a foundation for understanding the interaction mechanism of coal slime and biomass cocombustion. The research findings also provide theoretical guidance for the safe operation of coal slime and biomass co-combustion equipment.