Abstract The spontaneous combustion of coal, if not eradicated immediately, may lead to coal ignition and even a full-blown fire. A new method, DSC Inflection Point (DSCIP), was proposed to determine the coal auto-ignition temperature (CAIT). Heat fluxes and kinetic parameters before and after CAIT were comparatively investigated through TG/DSC analysis and mathematical model construction. Meanwhile, the impacts of temperature rise rate and oxygen concentration on CAIT were studied and two indexes representing the hazard and destructiveness of coal spontaneous combustion, respectively, were proposed. The results demonstrated that the heat flux curve of coal spontaneous combustion can be well fitted using Gaussian mixture model. Compared to the oxidation stage, the released heat during the combustion stage was greatly increased. Furthermore, the activation energy became larger and the reaction order decreased to zero when the temperature exceeded CAIT. The study also found that CAIT was enhanced with the increase of temperature rise rates or the decrease of oxygen concentrations. Changes of heat flux, free radicals, and the activation energy proved the rationality and feasibility of the DSCIP method in determining CAIT. Additionally, under the same environmental conditions, lignite had the largest hazard of coal spontaneous combustion and the anthracite had the biggest destructiveness. Both the hazard and the destructiveness of coal spontaneous combustion became stronger as oxygen concentrations increased.

中文翻译：

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基于自燃温度的煤自燃风险评价

摘要 煤的自燃如不及时根除，可能导致煤自燃，甚至发生全面火灾。提出了一种新的方法，即 DSC 拐点 (DSCIP) 来确定煤的自燃温度 (CAIT)。通过TG/DSC分析和数学模型构建，比较了CAIT前后的热通量和动力学参数。同时，研究了升温速率和氧浓度对CAIT的影响，提出了分别代表煤自燃危害性和破坏性的两个指标。结果表明，使用高斯混合模型可以很好地拟合煤自燃的热通量曲线。与氧化阶段相比，燃烧阶段释放的热量大大增加。此外，当温度超过 CAIT 时，活化能变大，反应级数降为零。研究还发现，CAIT随着升温速率的增加或氧气浓度的降低而增强。热通量、自由基和活化能的变化证明了DSCIP方法测定CAIT的合理性和可行性。另外，在相同环境条件下，褐煤自燃危害最大，无烟煤破坏力最大。随着氧气浓度的增加，煤自燃的危害性和破坏性都变得更强。研究还发现，CAIT随着升温速率的增加或氧气浓度的降低而增强。热通量、自由基和活化能的变化证明了DSCIP方法测定CAIT的合理性和可行性。另外，在相同环境条件下，褐煤自燃危害最大，无烟煤破坏力最大。随着氧气浓度的增加，煤自燃的危害性和破坏性都变得更强。研究还发现，CAIT随着升温速率的增加或氧气浓度的降低而增强。热通量、自由基和活化能的变化证明了DSCIP方法测定CAIT的合理性和可行性。另外，在相同环境条件下，褐煤自燃危害最大，无烟煤破坏力最大。随着氧气浓度的增加，煤自燃的危害性和破坏性都变得更强。褐煤自燃危害最大，无烟煤破坏力最大。随着氧气浓度的增加，煤自燃的危害性和破坏性都变得更强。褐煤自燃危害最大，无烟煤破坏力最大。随着氧气浓度的增加，煤自燃的危害性和破坏性都变得更强。