神东煤回转窑热解破碎特性

Fragmentation characteristics of Shendong coal during pyrolysis in rotary kiln

为研究神东煤在回转窑热解过程的破碎特性,利用100 kg级回转窑研究了粒径25~13 mm的神华补连塔矿区神东煤的热解破碎特性,考察了加热终温、停留时间、回转窑转速3种反应条件对神东煤的碎裂粉化程度的影响。结果表明,在回转窑热解时,随温度升高(120~700℃),神东煤产物总碎裂率α由20.48%升至68.74%,粉化率β由1.70%升至16.55%;随停留时间增加,α由15.66%升至68.22%,β由1.32%增至15.71%;随回转窑转速增加,α由17.54%升至71.43%,β由1.26%增至15.08%。通过对神东煤回转窑热解过程破碎影响因素进行灰色关联分析,发现3种反应条件(反应终温、停留时间、回转窑转速)对热解产物总碎裂率和粉化率的影响顺序一致,其中加热终温影响程度最大,其次是停留时间,回转窑转速影响程度最小。建立了神东煤热解破碎过程粒径关联函数模型,模型充分反映了煤热解温度、停留时间和转速与粒径分布的关系,经验证破碎后平均粒径计算值与试验值的相对误差小于5%,能较好地预测神东煤在回转窑热解过程中破碎后的粒度变化情况。

In order to study the fragmentation characteristics of Shendong coal during pyrolysis process in the rotary kiln,the pyrolysis and crushing experimental of Shendong coal with a particle size of 25-13 mm were studied in a 100 kg rotary kiln.The effects of tempera⁃ture,residence time and rotary speed on the degree of fragmentation and pulverization of Shendong coal were investigated.The results show that with the increase of temperature(120-700℃),the total fragmentation rateαof Shendong coal products increases from 20.48%to 68.74%,and the pulverization rateβincreases from 1.70%to 16.55%;with the residence time increasing,theαincreases from 15.66%to 68.22%,and theβincreases from 1.32%to 15.71%;with the rotation speed of the rotary kiln increasing,theαincreases from 17.54%to 71.43%,theβincreases from 1.26%to 15.08%.Through the grey correlation analysis of the factors affecting the crushing of Shendong coal rotary kiln pyrolysis process,it is found that the three reaction conditions(final reaction temperature,residence time,rotary kiln speed)have the same order of impact on the fragmentation and pulverization rate of the product.The temperature has the largest impact,followed by the residence time,and the rotary kiln speed has the least impact.The particle size correlation function model of Shendong coal pyrolysis and fragmentation process was established,the model reflected the relationship between coal pyrolysis temperature,residence time and rota⁃tional speed on particle size distribution,and it is verified that the relative error between the calculated value and the experimental value of the average particle size after crushing is less than 5%,which can better predict the change of the particle size of Shendong coal during the pyrolysis process of the rotary kiln.