Highly efficient separation of benzene, toluene, and xylenes (BTXs) from pyrolysis gasoline is very important in petrochemical industries. Though the extractive distillation (ED) process is simpler and consumes less energy compared with liquid–liquid extraction process, it is difficult for a single solvent, for example, sulfolane, to achieve both high purity and high yield of BTXs. In this work, methylsulfonylethane (MSE) was chosen as a cosolvent to improve the selectivity of sulfolane after solvent screening, and factors that may affect the selectivity of the composite solvent were fully investigated, such as the content of cosolvent, solvent to feed ratio, the composition of the feed, and temperature. Furthermore, 240 h of continuous extractive distillation and solvent recovery experiment was carried out using sulfolane (85 wt%)–MES (15 wt%) mixture as solvent. The purity of mixed aromatics obtained was 99.83%, and the yield was as high as 99.7%.

中文翻译：

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以甲基磺酰乙烷为助溶剂从裂解汽油中萃取精馏苯、甲苯和二甲苯

从裂解汽油中高效分离苯、甲苯和二甲苯 (BTX) 在石化工业中非常重要。尽管与液-液萃取工艺相比，萃取蒸馏（ED）工艺更简单且能耗更低，但单一溶剂（例如环丁砜）难以同时获得高纯度和高收率的 BTX。本工作选择甲磺酰乙烷（MSE）作为助溶剂，在溶剂筛选后提高环丁砜的选择性，并充分考察了可能影响复合溶剂选择性的因素，如助溶剂的含量、溶剂与进料比、饲料的成分和温度。此外，使用环丁砜 (85 wt%)-MES (15 wt%) 混合物作为溶剂进行了 240 小时的连续萃取蒸馏和溶剂回收实验。所得混合芳烃纯度为99.83%，收率高达99.7%。