Design of the recovery section of the extracted aromatics in the separation of BTEX from naphtha feed to ethylene crackers using [4empy][Tf2N] and [emim][DCA] mixed ionic liquids as solvent

作者：Navarro Pablo; Larriba Marcos; Garcia Julian^*; Rodriguez Francisco

来源：Separation and Purification Technology, 2017, 180: 149-156.

DOI：10.1016/j.seppur.2017.02.052

• Mixed ionic liquids
• Aromatic/aliphatic separation
• Vapor-liquid separation
• Naphtha

Aromatic hydrocarbons are mainly obtained from reformer and pyrolysis gasolines by liquid-liquid extraction. In these streams, the content of aromatics is between 40 wt.% and 70 wt.%. However, several streams as the naphtha feed to ethylene crackers, in which the aromatics are between 10 wt.% and 25 wt. %, have not available technology to obtain a commercial stream of BTEX. In our previous contribution, the BTEX removing from a naphtha model with the minimum aromatic content, 10 wt.%, was studied using ionic liquids (ILs) as solvents. The high aromatic purity in the extract stream and the good extraction yields obtained suggested liquid-liquid extraction using ILs as a good technological election. To confirm this, in this work the vapor-liquid separation of all hydrocarbons from the solvent in the extract stream have been determined at several temperatures by using a headspace - gas chromatography (HS-GC) technique. After that, the operating conditions were simulated to maximize the purity and recovery of the aromatics. The proposed recovery section to selectively separate the aromatics from the extract stream consists in three flash distillation units that operate at low temperatures and high vacuum conditions, achieving an aromatic-rich stream with a purity of 98.5 wt.%.

• 出版日期2017-6-8