内蒙古鲁新煤矿褐煤燃烧特性及热动力学参数研究

马砺; 李登宇; 刘虎; 范晶; 赵祥凯; 严月圆; 陈荣; 裴广伟

doi:10.13347/j.cnki.mkaq.20250065

内蒙古鲁新煤矿褐煤燃烧特性及热动力学参数研究

Study on combustion characteristics and thermokinetic parameters of lignite from Lunxin Coal Mine in Inner Mongolia

摘要

摘要: 内蒙古鲁新煤矿11煤层煤种为褐煤，属于容易自燃煤层，煤自燃危险性较大。采用同步热分析仪研究了褐煤在不同升温速率(10、20、30、40 ℃/min)和氧气体积分数(9%、13%、17%、21%)条件下的燃烧过程，对比分析了特征温度点、失重速率、可燃性指数、综合燃烧特性指数及表观活化能等热动力学参数。结果表明：特征温度随升温速率增加和氧气体积分数减少呈升高趋势；升温速率和氧气体积分数对失水失重阶段质量损失和放热量影响不显著；氧气体积分数和升温速率增加会加强热解燃烧阶段的煤粉氧化反应，提高热释放速率，最大失重速率、综合燃烧特性指数、可燃性指数、放热量等特性参数也随之上升；升温速率为40 ℃/min时的最大失重速率为14.77%/min，相比升温速率10 ℃/min增加了25.8%，氧气体积分数21%相比9%，最大失重速率增加1.6倍，总放热量增长3.7倍；升温速率和氧气体积分数最高时，可燃性指数和综合燃烧特性指数分别达到最大值13.64×10⁻⁵和11.35×10⁻⁷；表观活化能随氧气体积分数的升高而上升，随转化率升高先增加后减少，转化率在0.30时达到最大值197.9 kJ/mol。氧气体积分数和升温速率的增加促使煤粉内部发生不完全反应的活性结构增加和反应活化能上升，两者共同耦合作用共同加快了氧化反应速率。

Abstract: The 11^# coal seam of Luxin Coal Mine in Inner Mongolia is lignite, which belongs to the easy spontaneous combustion coal seam, and the risk of coal spontaneous combustion is large. In this study, lignite from Luxin Coal Mine in Inner Mongolia was selected. The combustion process of lignite at different heating rates (10, 20, 30, 40 ℃/min) and oxygen volume fractions (9, 13, 17, 21%) was studied by synchronous thermal analyzer. The thermokinetic parameters such as characteristic temperature point, weight loss rate, flammability index, comprehensive combustion characteristic index and apparent activation energy were compared and analyzed. The results show that the characteristic temperature increases with the increase of heating rate and the decrease of oxygen volume fraction. The heating rate and oxygen volume fraction had no significant effect on the mass loss and heat release during the weight loss stage. The increase of oxygen volume fraction and heating rate will strengthen the oxidation reaction of pulverized coal in the pyrolysis combustion stage and increase the heat release rate, and the maximum weight loss rate, comprehensive combustion characteristic index, flammability index, heat release and other characteristic parameters increase accordingly. When the heating rate is 40 ℃/min, the maximum weight loss rate is 14.77%/min, which is 25.8% higher than the heating rate of 10 ℃/min. The maximum weight loss rate at the oxygen volume fraction of 21% is 1.6 times higher than that of 9%, and the total heat release increases by 3.7 times. When the heating rate and oxygen volume fraction are the highest, the flammability index and the comprehensive combustion characteristic index reach the maximum values of 13.64×10⁻⁵ and 11.35×10⁻⁷, respectively. The apparent activation energy increases with the increase of oxygen volume fraction and increases first and then decreases with the increase of conversion rate. The conversion rate reaches its maximum value of 197.9 kJ/mol at 0.30. The increase of oxygen volume fraction and heating rate prompts the increase of active structure and activation energy of incomplete reaction in pulverized coal, and the coupling of the two accelerates the oxidation reaction rate.

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