热解气氛对煤焦油渣微观结构的影响

在工业危废煤焦油渣的综合利用研究中,通过热解实验制得热解渣,利用热解渣进行活性炭制备.采用X射线衍射(XRD)、拉曼光谱(Raman)和扫描电子显微镜(SEM)等分析手段获得热解渣的微观结构的变化信息,研究热解气氛对其微观结构演变的影响,探索煤焦油渣热解过程微观结构的变化规律.结果表明:在850℃热解条件下,煤焦油渣会...

Effects of Pyrolysis Atmosphere on the Microstructure of Tar Residue

In the study of comprehensive utilization of tarresidue, the pyrolysis residue was prepared by pyrolysis experiment, fromwhich, activated carbon was prepared. X-ray diffraction (XRD), Ramanspectroscopy (Raman) and scanning electron microscopy (SEM) were used to obtainmicrostructure change information. The effects of pyrolysis atmosphere on themicrostructure evolution of pyrolysis residue was studied, and the change ruleof microstructure was explored. Results show that tar residue undergoesthermoplasticity and intermediate temperature cross-linking polycondensation at850 ℃, microcrystalline layerforms a good effective stack, and the aromatic structural units tend to betransverse fracture and longitudinal thickening. A large number of highlyactive aromatic structures linked by cross-linking bonds are formed at thisstage. Increasing pyrolysis rate weakens cross-linking polycondensationreaction and increase pore size and number of particles, while prolonging thefinal temperature residence time gradually depolymerizes macromolecularstructures, making the longitudinal cracking more obvious and promoting theformation of more micropores. However, when pyrolysis temperature is too high,particle surface appears “collapse” phenomenon, resulting in areduction of micropores. The effects of cross linking polycondensation onthe increasing of lamellar size is more obvious. At this stage, pyrolytic slagbegins to transform into ordered graphite structure, particles shrink stronglyand micropores decrease greatly. The specific surface area of slow pyrolysisslag 8RJ850-10 is only 890.6 m²/g, while that of fast pyrolysis slag20RJ850-10 is 1151.6m²/g, indicating that increasing the heatingrate helps to increase the pore forming efficiency of activated carbon.