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

Abstract

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.

Extractive Distillation with Ionic Liquid Entrainers for the Separation of Acetonitrile and Water

“…Many typical examples of the extractive distillation process with an IL entrainer for separating different mixtures can be found elsewhere. − For a typical two-component mixture, the extractive distillation process can be simply designed as a double-column process, which basically consists of one EDC and one SRC, additionally coupled to reboilers, condensers, intermediate heat exchangers, and pumps, as shown in Figure . The liquid mixtures of acetonitrile and water enter into the EDC from the middle position, and the entrainers are introduced from the top of this column.…”

Mixed Ionic Liquids as Entrainers for Aromatic Extraction Processes: Energy, Economic, and Environmental Evaluations

“…Although this method can reduce the temperature of the bottom of the column and prevent sulfolane from thermal decomposition, it will inevitably bring water as an impurity. Using a vacuum distillation column, Oh et al reduced the temperature of the bottom of the sulfolane recovery column and effectively solved the problem of sulfolane thermal decomposition. Taking this method as a reference, the alkane collection column in the sulfolane process and the benzene product column in all processes were designed as vacuum distillation columns with the top pressure being set at 0.08 bar and the total pressure drop at 0.1 bar.…”

“…It is very difficult to obtain pure aromatic compounds from petroleum fluids by common distillation methods because the boiling points of aliphatic hydrocarbons and aromatic hydrocarbons are close, and azeotropic behavior is often encountered for these mixtures. At present, the methods for separating mixtures of aromatic and aliphatic hydrocarbons include liquid–liquid extraction (suitable for mixtures containing 20–65 wt % of aromatics), extractive distillation (suitable for mixtures containing 65–90 wt % of aromatics), and azeotropic distillation (suitable for the mixtures containing 90 wt % and above of aromatics). , Liquid–liquid extraction is commonly used to separate and recover the aromatic compounds from petroleum products . One key issue for an efficient liquid–liquid extraction is the choice of an appropriate extractant.…”

Development of energy‐optimum aromatic extraction processes using ionic liquid [EMIM][NTf2]

“…Evaluating an IL process comparatively to conventional technology requires development of process simulation models. There are several prior studies of modeling an aromatic extraction process using IL solvents that have noted and dealt with various modeling challenges 5,6,8,9,11–20 . Table 1 summarizes important attributes we have identified for each prior study 5,6,8,9,11–20 .…”