二元溶剂萃取分离重油中芳烃的机理

石油重质馏分油中含有多种烃结构组分，如链烷烃、环烷烃以及不同环数芳烃，采用极性溶剂萃取分离工艺可以实现不同组分的分离，但一元溶剂萃取的精制油收率低、芳烃萃取选择性较差。以减压馏分油为原料，糠醛为主溶剂，含羟基的极性调节剂PR1为副溶剂，开展一元溶剂、二元溶剂单段萃取实验，通过对主溶剂溶解度参数的调配，提升溶剂萃取分离不同烃组分的效果。结果表明，与一元溶剂相比，二元溶剂对三环及以上的芳烃萃取选择性提升率超过100%，用一种新的基团贡献法计算了6种模型分子的溶解度参数，发现各芳烃的萃取选择性随芳烃溶解度参数的增大而增大。考察了不同PR1加入量的二元溶剂萃取效果，结合二元溶剂溶解度参数变化与溶剂核磁共振氢谱(¹H-NMR)化学位移变化，发现溶剂体系氢键作用的变化是溶剂萃取效果产生差异的根本原因。

Mechanism of Binary Solvent Extraction and Separation of Aromatics From Heavy Oils

Heavy petroleum distillates contain different hydrocarbon components, such as paraffins, cyclo-paraffins and aromatics with different ring numbers. Separation of different components can be achieved with using of polar solvent extraction. However, for single solvent extraction, extraction yield is low and aromatics selectivity is poor. In this work, with using VGO as feedstocks, liquid-liquid extraction was performed with applying different polar organic solvents. With using furfural as the main solvent and polarity regulator (PR1) as co-solvent, single solvent and binary solvent single-stage extraction experiments were performed. By adjusting solubility parameters of different solvents, separation efficiency for aromatics and saturated hydrocarbons can be improved. Experimental results show that, compared with single solvent, extraction selectivity for tricyclic + aromatics can be inmproved more than 100% with using binary solvent. In addition, solubility parameters of six different model molecules are calculated with a novel group contribution method. It is found that extraction selectivity of different aromatics increases proportionally with their solubility parameters. Extraction results of binary solvent with different amounts of PR1 was also investigated. Through studying solubility parameters of different binary solvents and their ¹H-NMR chemical shifts, it can be concluded that hydrogen bonding strength in different solvents determines their extraction performance.