A study on the combustion characteristics and kinetic parameters of coal during the inertization process at different metamorphic degrees

IF 3 3区 工程技术 Q2 CHEMISTRY, ANALYTICAL
Bo Tan, Feiran Wang, Jiliang Huang, Chang Su, Liyang Gao, Xiyang Fang, Haiyan Wang, Tianze Li
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Abstract

To examine the impact of different heating rates and oxygen concentrations on the combustion characteristics and kinetic parameters of coals at various metamorphic degrees, this study selected four different metamorphic degrees as experimental subjects. Thermogravimetric experiments were conducted under various heating rates and oxygen concentrations to obtain characteristic temperature points, mass loss rates, and heat absorption and excretion characteristics of coal samples under different conditions. Furthermore, reaction mechanism functions were determined, and the reaction kinetics "three factors" of coal samples under different conditions were calculated to ascertain activation energy. Based on characteristic temperature points, different phases of coal spontaneous combustion were delineated, and the oxidative characteristics of coal samples at each phase were analyzed. The study explored the impact mechanisms of different temperatures and oxygen concentrations on coal spontaneous combustion from the perspectives of characteristic temperature points and activation energy. The results indicate that inertization, meaning the introduction of inert gases, has an inhibitory effect on the coal–oxygen complex process for coals at different metamorphic degrees. As the degree of inertization increases, the two phases most affected are the oxygen uptake and mass gain phase and the combustion phase. Compared to the oxygen uptake and mass gain phase, the TG curve of the combustion phase shows a delayed phenomenon with increased inertization degree. With rising temperature, the overall trend of the DTG curve initially decreases, followed by an increase, and then reaches a steady plateau, with the minimum value occurring at the trough. The maximum mass loss rate of coals at different metamorphic degrees decreases with an increase in inertization degree, indicating that inertization inhibits the coal oxidation process. Additionally, the temperature points corresponding to the maximum exothermic rate all shift backward. The DSC curves of coal samples exhibit an overall trend of initial decrease followed by an increase with temperature variation. With enhanced inertization degree, the maximum exothermic rate of coals at different metamorphic degrees decreases, and the corresponding temperature points shift backward. As the inertization intensity decreases, the activation energy (Ea) of the low-temperature oxidation phase generally decreases for coals at four different metamorphic degrees. Under the same inertization intensity, coals with higher metamorphic degrees have higher activation energy. This study can provide theoretical support for the prevention and control of coal spontaneous combustion.

Abstract Image

不同变质程度煤在惰化过程中的燃烧特性和动力学参数研究
为了研究不同加热速率和氧气浓度对不同变质程度煤炭的燃烧特性和动力学参数的影响,本研究选取了四种不同变质程度的煤炭作为实验对象。在不同加热速率和氧气浓度下进行热重实验,以获得不同条件下煤样的特征温度点、质量损失率、吸热和排热特征。此外,还确定了反应机理函数,并计算了不同条件下煤样的反应动力学 "三要素",从而确定了活化能。根据特征温度点,划分了煤炭自燃的不同阶段,并分析了各阶段煤样的氧化特性。研究从特征温度点和活化能的角度探讨了不同温度和氧气浓度对煤炭自燃的影响机制。结果表明,对于不同变质程度的煤炭,惰化(即引入惰性气体)对煤-氧复合过程有抑制作用。随着惰化程度的增加,受影响最大的两个阶段是吸氧增质阶段和燃烧阶段。与吸氧增质阶段相比,燃烧阶段的 TG 曲线随着惰化度的增加而出现延迟现象。随着温度的升高,DTG 曲线的总体趋势是先减小,后增大,然后达到一个稳定的高点,最小值出现在低谷。不同变质度煤炭的最大质量损失率随惰化度的增加而降低,表明惰化抑制了煤的氧化过程。此外,最大放热率对应的温度点均向后移动。煤样的 DSC 曲线随着温度的变化呈现出先降低后升高的总体趋势。随着惰化程度的提高,不同变质程度煤炭的最大放热率降低,相应的温度点向后移动。随着惰化强度的降低,四种不同变质程度的煤的低温氧化相活化能(Ea)普遍降低。在相同的惰化强度下,变质度越高的煤的活化能越高。该研究可为防治煤炭自燃提供理论支持。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
CiteScore
8.50
自引率
9.10%
发文量
577
审稿时长
3.8 months
期刊介绍: Journal of Thermal Analysis and Calorimetry is a fully peer reviewed journal publishing high quality papers covering all aspects of thermal analysis, calorimetry, and experimental thermodynamics. The journal publishes regular and special issues in twelve issues every year. The following types of papers are published: Original Research Papers, Short Communications, Reviews, Modern Instruments, Events and Book reviews. The subjects covered are: thermogravimetry, derivative thermogravimetry, differential thermal analysis, thermodilatometry, differential scanning calorimetry of all types, non-scanning calorimetry of all types, thermometry, evolved gas analysis, thermomechanical analysis, emanation thermal analysis, thermal conductivity, multiple techniques, and miscellaneous thermal methods (including the combination of the thermal method with various instrumental techniques), theory and instrumentation for thermal analysis and calorimetry.
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