文摘
Reformer and pyrolysis gasolines are the main benzene, toluene, ethylbenzene, and xylenes (BTEX) sources. In our previous works, the aromatic extraction from reformer and pyrolysis gasoline models formed by three n-alkanes, benzene, toluene, and xylenes were studied using a binary mixture of ionic liquids (ILs). The results showed that the {[4empy][Tf2N] + [emim][DCA]} IL mixture with [4empy][Tf2N] mole fraction of 0.3 required a comparable countercurrent extraction column to that of the Sulfolane process, and extracted BTEX had quite a higher purity using the IL mixture in the three gasoline models analyzed. Here, we have studied the hydrocarbon recovery from the extract stream obtained in these works. For that purpose, the vapor–liquid equilibria (VLE) data involving the extracted hydrocarbons and the IL mixed solvent have been determined by the headspace–gas chromatography (HS–GC) technique for several temperatures. Afterward, the simulation of two new process configurations based on adiabatic flash distillation units was carried out using a new algorithm developed in the framework of this study, useful for further flash distillation cases with a high concentration of IL or non-volatile character compounds. The commercial purity obtained in the aromatic product stream (99.9 wt %) has demonstrated the technical feasibility of the aromatic extraction process using ILs as solvents, including the hydrocarbon recovery section.
