低阶煤快速干馏残渣中萃取沥青的热解特性研究

Study on Pyrolysis Characteristics of Extracted Pitch from Residue of Rapid Destructive Distillation of Low Rank Coal

对低阶煤干馏残渣的高效利用是实现低阶煤洁净、高效利用的重要途径之一。该文以洗油为萃取剂对低阶煤快速干馏残渣进行萃取处理得到萃取沥青。利用热失重分析仪研究了萃取沥青的热解动力学。采用Flynn-Wall-Ozawa和Kissinger-Akahi-ra-Sunose计算了萃取沥青的热解反应活化能,并结合Satava-Sestak分析方法求解热解反应动力学参数。实验结果表明G(α)=[-ln(1-α)]~4是最佳机理函数(n=4),反应活化能为91.43 kJ/mol,指前因子A=4.07×10^(13) min^(-1)。将萃取沥青进行热转化处理得到沥青焦,利用偏光显微镜、显微强度测试和拉曼光谱以及相应的分峰拟合等方法对萃取沥青焦的性质进行了研究。结果表明:萃取沥青焦是以中粒镶嵌结构(Mm)和细粒镶嵌结构(Mf)为主的镶嵌结构沥青焦,其显微强度为85.05%,石墨碳微晶含量I_(G)/I_(All)为15.13%,无定形碳含量I_(D3)/I_(All)为12.07%。该研究从沥青回收与利用角度探究低阶煤干馏残渣的利用途径,为实现低阶煤洁净、高值利用提供一定理论依据和实验依据。

The efficient use of low rank coal distillation residue is one of the important ways to achieve clean and efficient use of low rank coal.The extracted pitch was obtained by extracting the residue of rapid destructive distillation of low-rank coal using washing oil as solvents.The pyrolysis kinetics of the extracted pitch was investigated using a thermogravimetric analyzer.The activation energy of the pyrolysis reaction of the extracted pitch was calculated using Flynn-Wall-Ozawa and Kissinger-Akahi-ra-Sunose,and the kinetic parameters of the pyrolysis reaction were solved using the Satava-Sestak analysis method.The experimental results showed that G(α)=[-ln(1-α)]~4 was the optimal mechanism function(n=4),with a reaction activation energy of 91.43 kJ/mol and a pre-exponential factor of A=4.07×10~(13).The extracted pitch was subjected to thermal conversion treatment to obtain pitch coke.The properties of the extracted pitch coke were studied using methods,e.g.,polarizing microscopy,microstrength testing,Raman spectroscopy,and the corresponding peak fitting.The results showed that the extracted pitch coke was a mosaic structure mainly composed of medium particle mosaic structure(Mm) and fine particle mosaic structure(Mf).The microstrength of the pitch coke was 85.05%,the graphitic carbon microcrystal content(I_G/I_(All)) was 15.13%,and the amorphous carbon content(I_(D3)/I_(All)) was 12.07%.This study explores the utilization pathways of low rank coal carbonization residue from the perspective of asphalt recovery and utilization,providing a theoretical and experimental basis for achieving clean and high-value utilization of low rank coal.