Conceptual Design of an Energy-Efficient Process for Separating Aromatic Compounds from Naphtha with a High Concentration of Aromatic Compounds Using 4-Methyl-N-butylpyridinium Tetrafluoroborate Ionic Liquid

To obtain aromatic compounds from a crude mixture such as reformate or pyrolysis gasoline, three different processes are simulated with the realistic composition of reformate and product specification. Simulations were performed by Aspen Plus supported with COSMO-RS method to predict the physical and thermodynamic properties of ionic liquid. Furthermore, utility analysis and economic evaluation are presented. Conventionally, aromatic compounds are extracted from a crude mixture either by extraction or by extractive distillation using a solvent such as sulfolane and separated by a series of distillation columns. In this study, the sulfolane-based commercial process is first introduced, and two novel processes that use 4-methyl-N-butylpyridinium tetrafluoroborate ionic liquid as solvent are proposed. The second process shows that energy consumption has successfully decreased, but the high price of ionic liquid offset the cost advantage. The third process is therefore proposed to reduce the amount of ionic liquid using two extractions. A similar level of energy saving is achieved with reduced costs.