Inhibiting effects of a proanthocyanidins/sodium polyacrylate composite on the spontaneous combustion of long-flame coal.

Proanthocyanidin antioxidant was first selected for study, and the inhibitory effect of proanthocyanidin and the optimal mass ratio of 6 mass% were obtained through temperature-programmed experiments. To compensate for the inhibitory effect and action time of a single antioxidant, a composite inhibitor with a physical and chemical synergistic effect was obtained through compounding with sodium polyacrylate, a superabsorbent resin, which improved the inhibitory effect on the spontaneous combustion of long-flame coal. In addition to the temperature-programmed experiments, the spontaneous combustion of long-flame coal was researched through a thermogravimetric (TG)–differential scanning calorimetric (DSC) experiment, and the optimal compound ratio of proanthocyanidins/sodium polyacrylate was determined to be 1:4. Under this ratio, the inhibition rate was close to 88% when the coal temperature ranged from 40 to 130 °C. The TG–derivative TG curve moved to the high-temperature region, and the composite inhibitors improved the characteristic temperature of raw coal and reduced its mass loss. The temperature corresponding to the peak value of the DSC curve increased, and the maximum heat release power was reduced. Fourier-transform infrared spectroscopy experiments revealed that the intensity of the hydroxyl peaks was reduced with the addition of composite inhibitors, and the peak intensity of methyl and methylene was lower than that of the raw coal. The inhibition characteristics of the composite inhibitor were thus obtained through a study of the change pattern of functional groups of coal samples during the heating process. [ABSTRACT FROM AUTHOR]