不同变质程度煤氧化特征指标量化分析

    Quantitative analysis of oxidation characteristic indicators of coal with different metamorphic degrees

    • 摘要: 为了研究不同变质程度煤氧化特征指标变化规律,采用程序升温实验系统分别对不黏煤(BN)、气肥煤(QF)和1/3焦煤(1/3JM)氧化过程进行了测试分析,确定了不同氧化阶段的表观活化能,量化计算了煤自燃极限参数变化特征。结果表明:低变质程度煤的表观活化能比高变质程度煤的低,BN、QF、1/3JM煤样平均表观活化能分别为39.90、65.28、69.43 kJ/mol,煤的表观活化能与其变质程度呈正相关关系,低变质程度煤自燃危险性更高;同一煤种不同阶段的表观活化能也不相同,BN、QF和1/3JM煤样阶段一表观活化能分别为55.28、75.05、80.79 kJ/mol,阶段三则分别为23.23、59.07、61.50 kJ/mol,整体随氧化反应深入而降低;3个煤种自燃极限参数极值点温度分别为50.3、61.5 、59.7 ℃,低变质程度煤比高变质程度煤的极值点温度要低;相同条件下,低变质程度煤最小浮煤厚度和下限氧气体积分数更小,上限漏风强度更大,更容易发生自燃,而变质程度相近的煤种,其氧化特征参数接近。

       

      Abstract: In order to study the changes of oxidation characteristics of coal with different degrees of metamorphism, the oxidation process of non-sticky coal (BN), gas-fat coal (QF) and 1/3 coking coal (1/3JM) was tested and analyzed by temperature programmed experiment system, the apparent activation energy of different oxidation stages was determined, and the change characteristics of spontaneous combustion limit parameters of coal were quantitatively calculated. The results show that the apparent activation energy of coal with low metamorphism is lower than that of coal with high metamorphism. The average apparent activation energy of BN, QF and 1/3JM coal samples is 39.90, 65.28 and 69.43 kJ/mol, respectively. The apparent activation energy of coal is positively correlated with its metamorphism, and the spontaneous combustion risk of coal with low metamorphism is higher; the apparent activation energy of the same coal at different stages is also different. The apparent activation energy of BN, QF and 1/3JM coal samples at stage 1 is 55.28, 75.05 and 80.79 kJ/mol, respectively, and that of stage 3 is 23.23, 59.07 and 61.50 kJ/mol, respectively, which decreases with the depth of oxidation reaction; the extreme temperature points of the three coal spontaneous combustion limit parameters are 50.3, 61.5 and 59.7 ℃, respectively. The extreme point temperatures of low-metamorphic coals are lower than those of high-metamorphic coals; under the same conditions, the minimum floating coal thickness and lower oxygen volume fraction of low metamorphism coal are smaller, the upper air leakage intensity is larger, and the spontaneous combustion is more likely to occur.

       

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