Research on combustion properties and thermokinetic of pulverized coal: raw and pre-oxidized samples

Abstract

The combustion behaviors of raw and pre-oxidized samples for two pulverized coals (PC) were investigated using a thermogravimetric (TG) analyzer. The mass variations, characteristic temperatures and combustion characteristic parameters, et al. of PC during oxidation combustion were analyzed. The results demonstrated that the ignition temperatures (T i) and burnout temperatures (T b) of pre-oxidized PC were lower than those of raw PC. The total mass losses of the four samples were 91.33, 92.32, 88.85, and 90.02 mass% respectively, which were consistent with the volatile matter and fixed carbon contents (Vad+FCad). The calculated combustion characteristic parameters (the ignition index C i, burnout index C b, and comprehensive combustibility index S n) of pre-oxidized samples were all greater than those of raw samples, which indicated that pre-oxidized PC was more prone to self-ignition than raw PC under the same conditions. The thermokinetic parameters of PC during pyrolysis and combustion were studied by Coats–Redfern method. The apparent activation energy E a of these four PC samples ranged from 45.12 to 55.37 kJ/mol.