Inhibiting effect of CO(2) on the oxidative combustion thermodynamics of coal

A thermal analysis experiment was conducted in O(2)/N(2)/CO(2) and O(2)/N(2) atmospheres (O(2) concentrations were 21, 14, 8, and CO(2) concentrations were 0, 39, 46, 52) to investigate the thermal behavior of coal oxidation and combustion. Results demonstrated that an elevated CO(2) concentration or decreased O(2) concentration had a delaying effect on the thermogravimetric analysis and differential scanning calorimetry (DSC) curves; moreover, the characteristic temperatures were substantially augmented. When the O(2) concentration was 21 vol%, the total heat released by coals A (highly volatile bituminous coal) and B (anthracite coal) decreased by 5.8% and 4.1%, respectively, after CO(2) addition. The comprehensive combustion performance index was also lowered. The DSC curve can be divided into two exothermic peaks, and the ratio of the peak 1 to peak 2 areas decreased with the addition of CO(2,) which indicated that CO(2) inhibited the oxidation of the active functional groups of coal structures. Apparent activation energy in O(2)/CO(2)/N(2) was less than that in O(2)/N(2).