中低温煤焦油蒸馏过程中金属元素的迁移规律

以中低温煤焦油轻油和重油为实验原料，采用常压蒸馏获得170~200℃、200~240℃、240~270℃、270~300℃、300~320℃、320~340℃、340~360℃和360~390℃煤焦油馏分油；利用配有油品加氧制冷进样系统的ICP-OES测定了21种微量元素在馏分油中的含量，考察了不同馏分油中元素的分布情况。研究表明：在原煤焦油中，未发现Ag、Mg、Mo、Na、Ni、Fe、Mn、Cr及Ti元素，含量较高的元素有Sn、P、Al、Pb、Si，其中Sn元素在轻油和重油中的含量分别为11.78μg/g和14.04μg/g；在所有馏分油中，未发现Al、Mo、Fe、Mn、Cr及Ti元素，含量比较高的元素有Si、Sn、Na、Zn、Pb，特别是Si、Na、Sn、Zn、Ni、Pb及B元素可以有效富集于馏分油中。可能的原因是Ca、Fe、Mg、Al等金属以不同的盐类形态存在，在煤焦油脱水及<170℃蒸馏过程中，这些金属盐类会被部分带出，导致其在馏分油中的含量未富集或未检出；通过关联金属元素在馏分油中的分布与其组成的关系，馏分油中元素的分布可能与酚类化合物、杂环化合物和蒸馏温度等相关。酚类化合物及杂环化合物可能与Ag、B、Cu、Mo、Sn、Na、Zn、Ca、Pb等金属形成络合物或卟啉配合物，蒸馏温度一方面可以破坏Sn、Cd、Pb、Zn、Cu、Ca、Pb等元素在馏分油中的结合力，另一方面也可以促进这些元素与馏分油中的含氧、含氮等化合物更好地发生化合反应，进而影响金属元素在馏分油中的含量分布。

Migration law of metal elements during distillation of low temperature coal tar

The light oil and heavy oil of low temperature coal tar were used as the experimental materials, and the distillate oil of 170-200℃, 200-240℃, 240-270℃, 270-300℃, 300-320℃, 320-340℃, 340-360℃ and 360-390℃ in coal tar were obtained by atmospheric distillation. The distribution of 21 microelements in each distillate oil was determined by ICP-OES equipped with an oxygen and cooling injection system for oil, and the distribution of elements in the distilled fractions was investigated. The results showed that in the light oil and heavy oil no Ag, Mg, Mo, Na, Ni, Fe, Mn, Cr and Ti elements were found, and the higher content of elements were Sn, P, Al, Pb and Si. The contents of Sn in light oil and heavy oil were 11.78μg/g and 14.04μg/g, respectively. In the distillate oil of light oil and heavy oil no Al, Mo, Fe, Mn, Cr and Ti elements were found, and the higher content of elements are Si, Sn, Na, Zn and Pb, especially, Si, Na, Sn, Zn, Ni, Pb, and B were the main elements that can be effectively enriched in distillate oil. The possible reason was that the metals, such as Ca, Fe, Mg and Al, were mainly in the form of oxide salts. During the process of distillation dehydration lower than 170℃, the oxide salts of these metals were partially distilled, which caused the content of these elements to be not enriched or undetected in the distillate oil. By associating the relationship between the distribution of the metal elements and its composition in the distillate oil, the distribution of elements in distillate oil may be related to phenolic compounds, heterocyclic compounds and distillation temperature. The phenolic compounds and the heterocyclic compounds can form complexes or porphyrin complexes with metals such as Ag, B, Cu, Mo, Sn, Na, Zn, Ca and Pb. The distillation temperature, on one hand, can destroy the binding of Sn, Cd, Pb, Zn, Cu, Ca and Pb in the distillate. On the other hand, these elements can be promoted to better react with the oxygenated and nitrogen compounds in distillate oil, thus affecting the content distribution of metal elements in the distillate.