Stripping Columns to Regenerate Ionic Liquids and Selectively Recover Hydrocarbons Avoiding Vacuum Conditions

There are a large number of liquid–liquid extraction processes where ionic liquids (ILs) are proposed as solvents. However, the development of purification and IL regeneration units still represents a challenge. Several effective separation trains were proposed to regenerate ILs, but extreme vacuum is needed to achieve commercial standards, which demands extra energy and extra solvent consumptions due to recycling streams. In this proposal, the use of stripping columns stands as a promising IL regeneration technology to avoid vacuum conditions and to enhance the separation of the compounds that form the extract stream, explored in the aromatic–aliphatic separation. COSMO-based/Aspen Plus methodology is applied to extensively evaluate the role of the IL nature and easily evaluate the influence of the main operating variables, namely, temperature feed, column pressure, reboiler heat, and number of stages, in the separation efficiency. A critical comparison between the current proposal and the benchmark IL regeneration process is reported, analyzing the aromatic recovery, energy duty, and operating cost. The use of two stripping columns for the IL regeneration stage evidences the potential of this new configuration, drawing a new paradigm in which mild conditions are enough to conceptually design new separation processes involving ILs.