Revealing reactive mechanism and nitrogen transformation of HSW coal combustions at molecule and particle scales

Understanding reactive mechanism of coal thermochemical conversion was the scientific fundamental for coal high-efficient utilization. However, the evolution of coal macromolecular structure, reactants and products remained unclear, in particularly at particle and molecular scales. The complex reaction networks for transformation of pollution elements were also not established. This work uncovered reactive mechanism and nitrogen transformation of HSW coal combustion at microscopic scales via reactive force field molecular dynamics method. The effects of chemical equivalent and combustion temperature were investigated to explore coal structural evolution, combustion reactants and products during reactive process. It was found that the fracture change of coal structure was observable with the continuous reaction. Based on the analysis of nitrogen-containing molecules in coal combustion, it was confirmed that HCN was an important nitrogen-containing intermediate. Further, the transformation networks of organic nitrogen in combustions were established, and the pathway for formation of HCN, NO and NO2 was obtained.