过滤精度对煤焦油QI的组成和结构的影响

采用精度为2~5μm和20~40μm的滤芯分别对煤焦油进行热过滤,从得到的滤渣中提取出喹啉不溶物(QI)。然后利用元素分析(EA)、激光粒度仪(LPSA)、扫描电子显微镜/X射线能量色散光谱(SEM/EDS)、傅里叶红外光谱(FT-IR)、X射线衍射仪(XRD)、X射线光电子能谱(XPS)等对所得煤焦油QI组分进行对比分析。结果表明:煤焦油QI组分芳构化程度高,有机物多为稠环类物质并带有很多侧链或杂质原子,同时存在少量石英石、方解石以及煤灰等无机物;当煤焦油热过滤时采用的滤芯精度较低时,最终提取出的QI组分缩聚度相对较高,并且稠环结构中所含侧链和杂原子也相对较少。经精度较低的滤芯热过滤后提取的QI组分中金属杂原子含量相对较高,这些金属杂原子主要存在于大颗粒无机物中,部分存在于小颗粒有机物中。当滤芯精度较高时所得QI组分中主要含酚类、醚类和羧酸类有机物,酮类含量相对较少;反之,QI中则主要含酚类、醚类和酮类有机物。因此,煤焦油热过滤所选的滤芯精度不宜过高,尤其不宜选精度在5μm以下的滤芯。

Influence of filtration accuracy on the composition and structure of quinoline insolubles in coal tar

Thermal filtration of coal tar was carried out on two kinds of filter with the precision of 2-5 μm and 20-40 μm，respectively，and quinoline insolubles (QI) was extracted from the filtration residue.Then the composition and structure of these of QI were analyzed by EA，LPSA，SEM/EDS，FT IR，XRD and XPS，and so on.The results show that the QI components in coal tar had a high degree of aromatization and a lot of polycyclic aromatics with a lot of side chains or hetero atoms as well as a small amount of SiO2，CaCO3，coal ash，etc.when the low precision filter was used，the polycondensation of QI was much higher，and the condensed ring structure contained less side chains and lower heteroatoms.Meanwhile，the metal heteroatoms in the extracted QI components were relatively high，and these metal heteroatoms mainly presented in the large particles of inorganic matter and partly in the small particles of organic matter.However，when a high precision filter was employed，the QI components mainly contained phenols，ethers and carboxylic acid organic matter and fewer ketone；on the contrary，QI contained more phenols，ethers and ketones.In conclusion，the precision of filter should not be used too high，especially for the filter precision under 5 μm during a coal tar thermal filtration process.