Aspen Plus supported conceptual design of the aromatic–aliphatic separation from low aromatic content naphtha using 4-methyl-N-butylpyridinium tetrafluoroborate ionic liquid

Abstract Three different processes to separate aromatic hydrocarbons from a very low-aromatic-content (10 wt.%) naphtha with the 4-methyl-N-butylpyridinium tetrafluoroborate ionic liquid are analyzed. A computer-aid methodology recently developed in our group that integrates the molecular modeling and the process simulation via COSMO-based thermodynamic models in Aspen Plus is used. The most commonly drawn process scheme is proposed as Base Case Configuration and two alternative configurations, one adding water as a co-solvent (Configuration 1) and the other including a stripper between the extraction and the solvent regeneration (Configuration 2), are studied. The processes performance is evaluated through the aliphatic and aromatic product purities and recoveries, and the solvent and energy consumptions. The results show that the separation of aromatic hydrocarbons from this type of naphtha using ionic liquids is possible. The Base Case Configuration is not able to achieve the separation successfully. The addition of water as co-solvent guaranties this demand but increases the solvent and energy consumption. The intermediate stripper seems to be a promising alternative as it allows achieving high purity aliphatic and aromatic products without increasing the solvent or energy needs. The results demonstrate that the computational strategy used is capable to discriminate among complex and relatively similar process alternatives.