Abstract: Coal structure and reaction conditions are the main factors influencing coal pyrolysis reactions. To investigate the pyrolysis characteristics of coals with different metamorphic degrees, three typical coal samples (lignite, bituminous coal, and anthracite) were selected as research objects. Thermogravimetric analysis experiments were conducted under four heating rate conditions to analyze the pyrolysis behavior of coals under different reaction conditions. The evolution of functional groups was analyzed by in-situ infrared test. The change law of reaction activation energy was calculated by the modified Kissinger-Akahira-Sunose (KAS) method. The results showed that the reaction behavior of coal at different temperatures can be divided into the water evaporation stage, gas desorption stage, slow decomposition stage, rapid pyrolysis stage, and condensation stage. The greater the degree of metamorphism, the higher the characteristic temperature and the lower the reaction degree. The pyrolysis temperature difference between anthracite and lignite reached 104.3℃. At 1000℃, the residual masses of the three coal samples were 58.19%, 65.90%, and 89.49%, respectively. The heating rate primarily influences the degree of reaction in coal samples at specific temperatures, without fundamentally altering the reactions that may occur during coal pyrolysis. A higher heating rate results in a narrower and sharper differential thermogravimetry (DTG) peak, accompanied by a lower reaction extent at the same temperature. After entering the pyrolysis stage, the activation energy for lignite and bituminous coal exhibits minimal variation, remaining at approximately 210 and 255 kJ/mol, respectively. Anthracite exhibited a high degree of aromatic ring condensation, molecular symmetry, and low reactivity. Its functional groups demonstrate low absorbance and exhibit delayed response patterns relative to other coal samples. Upon entering the pyrolysis stage, it must overcome a higher reaction energy barrier to sustain the reaction.

Key words: coal fire disaster, pyrolysis characteristic, stage characteristics, functional group evolution, activation energy

摘要： 煤体结构与反应条件是影响煤热解反应的主要因素。为了研究不同变质程度煤的热解反应特性，本工作以三种典型变质程度煤为研究对象，在四种升温速率条件下开展热重测试，分析了不同反应条件下煤的热解行为；结合原位红外测试揭示了热解过程中官能团的演化规律，并采用改进的Kissinger-Akahira-Sunose (KAS)法计算了反应活化能的变化规律。结果表明，煤的热解过程可依据不同温度区间的反应行为分为5个特征阶段，变质程度越大，特征温度越高，反应程度越低，无烟煤与褐煤热解温度差值达104.3℃，1000℃下三种煤样剩余质量分别为58.19%, 65.90%和89.49%。升温速率主要影响煤样在特定温度下的反应程度，并未改变煤热解过程所发生的反应路径。褐煤、烟煤进入热解阶段后活化能变化较小，分别维持在210和255 kJ/mol左右。无烟煤因芳环缩合程度及分子对称性高、反应活性低，官能团吸光度最低且变化规律滞后于其他煤样，在进入热解阶段后仍需跨越更高的反应能垒。

关键词: 煤火灾害, 热解特性, 阶段特征, 官能团演化, 活化能