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论文类型：期刊论文

发表时间：2021-02-09

发表刊物：JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY

卷号：137

期号：5

页面范围：1693-1705

ISSN号：1388-6150

关键字：Oxidized feature; Characteristic temperature; Spontaneous coal combustion; Functional group; Apparent activation energy

摘要：As to the continuous consumption of limited high-rank coal resources, low-rank bituminous coal is gradually grabbing more attention to the utilization for power resources and industrial production. However, the high risk of spontaneous combustion of low-rank coal has gradually become one of the most critical hazards worldwide during coal mining, storage, and applications. Thermogravimetry coupled with Fourier transform infrared spectrometry using a nonisothermal program method was employed to investigate the oxidized features of two low-rank coals from Jurassic strata. According to initial, first- and second-derivative thermogravimetric curves, an improved quantitative method for determining the eight characteristic temperatures of the coal oxidation process was proposed. The indexes and implications for the thermal hazard of spontaneous coal combustion during stages I-IV, based on the characteristic temperatures, were analyzed. By examining the functional groups, microcharacterization at each characteristic temperature of the coal was obtained. Three kinetic methods were used to calculate the apparent activation energy (Ea). The evolution of Ea was stage III>stage IV>stage II>stage I. The results demonstrated that the integral mechanism in the four stages described a second-order chemical reaction. Moreover, the pre-exponential factor and Ea were positively correlated.