Model-free and model-based kinetics of the combustion process of low rank coals with high ash contents using TGA-DTG-DTA-MS and FTIR techniques

Abstract

Thermal and kinetics behaviors of the low-rank coals from different annual periods (Kolubara (2015)/(2018) and TENT A (2015)/(2018)) during combustion process in air atmosphere, using simultaneous TGA-DTG-DTA-MS measurements were investigated. The FTIR spectroscopy was used to gain additional information on coals structures. Kolubara and TENT A coals from (2015)/(2018) annual periods show differences in reactivity, where the reason for this demeanor lies in differences in decomposition kinetics of these coals. The conclusions made on the basis of model-based analysis clearly indicate that differences in combustion reaction pathways (especially in transitions from primary to secondary combustion stages) arise from continual changes in physical structure of the coals. It was found that the mineral matter significantly influences on the reactivity of coal during combustion, where this is particularly pronounced for TENT A coal particles.