肥煤自燃全过程热动力学特征参数研究

Study on Characteristics of Thermo Kinetic Behavior During Fat Coal Spontaneous Combustion

实验测定了林西矿肥煤样品30~900℃煤自燃全过程热动力学特征参数,得出:TG/DTG曲线显示煤样DTG初始临界温度45℃,干裂温度122℃,活性温度195℃,增速温度265℃,质量极大值温度342℃,着火温度465℃,最大热失重速率温度515℃和燃尽温度690℃;DSC曲线显示,煤样初始放热温度60℃、最大热释放速率温度511℃。结合TG-DTG-DSC曲线综合分析可知,煤温达到510℃左右时煤样反应最剧烈。由煤自燃标志气体测定实验系统得出:煤温130℃后CO,CO 2释放量迅速增加,210℃增加速度下降;CH 4,C 2 H 6含量变化具有规律性且两者变化相近;C 2 H 4出现温度为130℃;C 2 H 4/C 2 H 6比值在190~350℃有较强的规律性,呈上升趋势且上升速度较快;350℃之后,CH 4,C 2 H 6,C 2 H 4体积分数均开始急剧增大;C 2 H 4/CO与C 2 H 4/CO 2变化趋势大致相同,在130~350℃时缓慢增长,达到350℃后比值呈指数形式上升。经拟合曲线,得到活化能的3个突变点温度:70,180,220℃,其中180℃与交叉点温度相吻合。通过以上研究,得到了肥煤自燃全过程的热力学特征参数,为实际生产中防治煤自燃提供了理论依据。

The thermodynamic characteristics of coal spontaneous combustion at 30℃to 900℃of fat coal in Linxi coal mine were measured.The following results were obtained.Based on TG/DTG curve analysis,the critical temperature of spontaneous combustion of coal sample during the temperature programmed process was determined to be 45℃,dry cracking temperature 122℃,active temperature 195℃,increasing speed 265℃,mass maximum temperature 342℃,ignition temperature at 465℃,the maximum thermal weight loss rate was 515℃and the burnout temperature was 690℃.From the DSC curve,the initial exothermic temperature of the coal sample was 60℃and the maximum heat release rate was 511℃.Combined with TG-DTG-DSC,it was found that the combustion was most intense when the temperature reached 510℃after the ignition of the coal sample.The experimental system for measuring the marker gas of coal shows that the release of CO and CO 2 increases rapidly after the coal temperature is 130℃,and the increase rate of 210℃decreases.The changes of CH 4 and C 2 H 6 content are similar and good,which can reflect the spontaneous combustion law of coal samples and start to produce C 2 H 4.The temperature is 130℃;the ratio of C 2 H 4/C 2 H 6 is strong at 190℃to 350℃,showing an upward trend and a rising speed;after 350℃,the concentrations of CH 4,C 2 H 6 and C 2 H 4 start to increase sharply;The change trends of C 2 H 4/CO and C 2 H 4/CO 2 are about the same,and they grow slowly between 130 and 350℃.After reaching 350°C,the ratio increases exponentially;the three apparent activation energy mutation points:70℃,180℃,220℃,of which 180℃coincides with the junction temperature.Through the above research and results,the thermodynamic characteristics parameters of coal spontaneous combustion process are obtained,which provide a theoretical basis for the prevention and control of coal spontaneous combustion in actual production.