不同快速裂解气氛下的烟煤表面微观特性

Investigation into microscopic characteristics of bituminous surface under different fast pyrolysis conditions

采用实验工况与电站煤粉锅炉相近的管式炉实验装置,分别制取了N2,φ(N2)=83.4%∶φ(CO2)=16.6%,φ(N2)=81.6%∶φ(CO2)=16.6%∶φ(O2)=1.8%3种气氛下神木烟煤快速裂解的煤焦.结合扫描电子显微镜和烟气分析仪检测发现,与煤粉处于堆积态的慢速热解不同,3种气氛下煤快速热解时破碎的小颗粒较多,随着停留时间的增加,煤焦表面的小孔结构逐渐增多;与N2气氛下相比,加入CO2后煤焦表面变得更致密,再加入O2后,随着停留时间的增加,煤焦表面发生微弱燃烧.

In a drop tube furnace with the combustion conditions similar to those of actual pulverized coal furnace,ShenMu bituminous coal char of fast pyrolysis conditions are prepared under different reaction atmospheres of N2,φ（N2）=83.4%∶φ（CO2）=16.6%,φ（N2）=81.6%∶φ（CO2）=16.6%∶φ（O2）=1.8%.By means of scanning electron microscopy and flue gas analyzer,the achieved experimental results are quite different from slow pyrolysis of packing pulverized coal.Under fast pyrolysis conditions,more small particles of coal crushing are found.With increasing residence time,the small holes on the surface of char gradually increase.Compared with N2 atmosphere,the surface of the char under φ（N2）=83.4%∶φ（CO2）=16.6% atmosphere becomes more densely.Finally,with increasing residence time,under φ（N2）=81.6%∶φ（CO2）=16.6%∶φ（O2）=1.8% atmosphere,some weak fire is found on the surface of the coal char.