Search

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]

In order to explore the characteristics of spontaneous combustion of Jurassic coal in northern Shaanxi with low metamorphic degree and high coke content, DSC differential scanning calorimeter and diffuse in situ infrared spectroscopy experiment were used to study and analyze the dynamic evolution law and interaction relationship between macroscopic thermal effect and microstructure in the spontaneous combustion process of different coal seams in northern Shaanxi. The results show that there are three characteristic temperature points in the heat flow curve during the spontaneous combustion of Jurassic coal in northern Shaanxi, which can be divided into four stages according to the characteristic temperature points. It was found that the consumption and production of functional groups in Jurassic coal oxidation process were mainly in the absorption bands of aliphatic hydrocarbon, aromatic hydrocarbon and oxygen-containing functional groups, and CH3, CH2, C–H, OH and C=O were the most active key functional groups in the process of coal oxidation. The dynamic correlation degree between heat flux intensity and key active groups is established by using dynamic grey correlation mathematics method. It is concluded that C=O bond has the highest correlation with heat flow intensity during coal oxidation, and has the greatest influence on heat flow intensity. The correlation values of the active groups CH3 and CH2 are second only to the C=O bond, and they are easy to react with oxygen, accompanied by the reaction heat. Although the correlation degree between C–H and OH bond is lower than that of C=O, CH3 and CH2 bond, the correlation degree value is also high, and has certain contribution to the coal reaction heat. These research results have important guiding significance for the development of targeted inhibitors for Jurassic coal spontaneous combustion disaster in northern Shaanxi. [ABSTRACT FROM AUTHOR]