Extraction of benzene from a narrow cut of naphtha via liquid-liquid extraction using pure-sulfolane and 2-propanol-sulfolane-mixed solvents (original) (raw)
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Industrial & Engineering Chemistry Research, 2006
Extraction of aromatics from naphtha reformate using a mixed solvent composed of propylene carbonate (PC) and diethylene glycol (DEG) has been considered in this study. Interaction parameters for DEG were obtained experimentally from the equilibrium data for two ternary systems (octane/toluene/DEG and octane/ PC/DEG). An experimental program was set up to study the extraction performance of aromatics using a mixed solvent system. On the other hand, a mathematical model was developed and compared with experimental data. Simulation results showed excellent agreement with the experimental results. Furthermore, an optimization model was developed to obtain the optimal extraction conditions, which minimize the operating cost and solvent losses. The optimization variables considered are solvent-to-feed ratio, solvent-to-solvent ratio, and operating temperature. The optimization model is highly nonlinear because of the fact that solvents and naphtha properties were estimated using the UNIFAC model. Optimization results were compared favorably with the experimental results.
The Journal of Chemical Thermodynamics, 2012
The phase equilibria for the extraction of aromatics from a petroleum naphtha reformate using a mixed solvent of 1-cyclohexyl-2-pyrrolidone (CHP) and ethylene carbonate (EC) are investigated and modelled using the UNIFAC group contribution method. The extraction runs have been carried out at various temperatures and solvent compositions. Experimental results are compared favourably with those predicted from the UNIFAC method. The solvent power, processing index, solvent selectivity and capacity for aromatic extraction from reformate are predicted successfully.
Extraction of Benzoic Acid and Naphthalene in Mixture
Extraction with acids and bases is typically used to separate organic compounds from one another based on their acid/base properties. The assumption is that organic compounds are more soluble in an organic solvent rather than water. If organic compound may be made ionic than it becomes more soluble in water. Around 0.100 grams of benzoic and around 0.100 grams of naphthalene were added to 5.0 ml of ether. Sodium bicarbonate was added in the amount of 3.5 ml around 1.0 ml at a time. The solution was properly mixed with each addition of sodium bicarbonate to allow for an organic layer and aqueous layer to properly develop and separate. The denser aqueous of sodium benzoate layer was found to be the bottom layer each time sodium bicarbonate was added and removed each time using a pipette tool. The sodium benzoate was transformed to its precipitate by the addition of hydrochloric acid. The precipitate was vacuum dried using a Hirsh flask and further dried on filter paper. The resulting benzoic acid was massed and calculated as a percentage recovered resulting in yield 0.0612 g initial 0.1128 g x 100=54.3 . The organic layer containing naphthalene and ether were dried out first with sodium sulfate, an anhydrous substance, in order to remove any water particles that may have contaminated from the aqueous layer. The organic layer then was boiled using a flask of water leaving a few drops of ether combined with naphthalene behind. In order to avoid sublimation naphthalene the remaining ether was boiled
Liquid -liquid equilibria data were measured at 293.15 K for the pseudo ternary system (sulfolane + alkanol) + octane + toluene. It is observed that the selectivity of pure sulfolane increases with cosolvent methanol but decreases with increasing the chain length of hydrocarbon in 1-alkanol. The nonrandom two liquid (NRTL) model, UNIQUAC model and UNIFAC model were used to correlate the experimental data and to predict the phase composition of the systems studied. The calculation based on NRTL model gave a good representation of the experimental tie-line data for all systems studied. The agreement between the correlated and the experimental results was very good.
Fluid Phase Equilibria, 1997
The phase equilibria for the extraction of aromatics from naphtha reformate (b.p. 60-135°C) in a mixed solvent of dimethylformamide (DMF) and ethylene glycol (EG) have been correlated using the UNIFAC group contribution model. The interaction parameters of DMF and EG with different hydrocarbon groups present in the reformate, such as CH 2 (paraffinic CH2), ACH (aromatic CH) and ACCH 2 (aromatic CCH2), and each of the two solvents were fitted to experimental concentrations of ternary systems containing these groups. The extraction runs were carried out at different temperatures, solvent compositions and solvent-to-feed ratios. The experimental results compared favorably with those predicted from the UNIFAC method. The minimum required energy for separation was achieved at 57°C using a 44% EG solvent with a solvent-to-feed ratio of 2.2 on a volume basis.
The Journal of Chemical Thermodynamics
The phase equilibria for the extraction of aromatics from a petroleum naphtha reformate using a mixed solvent of 1-cyclohexyl-2-pyrrolidone (CHP) and ethylene carbonate (EC) are investigated and modelled using the UNIFAC group contribution method. The extraction runs have been carried out at various temperatures and solvent compositions. Experimental results are compared favourably with those predicted from the UNIFAC method. The solvent power, processing index, solvent selectivity and capacity for aromatic extraction from reformate are predicted successfully.
Extraction of aromatics from naphtha reformate using propylene carbonate
Fluid Phase Equilibria, 2003
The phase equilibria of the extraction of aromatics from naphtha reformate with propylene carbonate as solvent has been studied. The phase equilibria data of paraffin/aromatic/propylene carbonate ternary systems available in literature along with data for the systems, cyclohexane/toluene/propylene carbonate and isooctane/ethyl benzene/propylene carbonate, generated in this study have been used to determine the interaction parameters of the following groups with propylene carbonate: CH 2 , ACH and ACCH 2 . The aromatics in the naphtha reformate were extracted at different temperatures (ranging from 303 to 333 K) and different solvent to feed molar ratios (ranging from 1.0 to 3.0). The experimental results obtained were found to compare favorably with those obtained by the UNIFAC model using the interaction parameters determined. The yield, solvent power and processing index along with solvent selectivity and capacity for aromatic extraction from the reformate can also be predicted successfully using the interaction parameters generated in this study. The operating conditions leading to maximum aromatic recovery have been optimized.
Journal of the Japan Petroleum Institute, 2009
Aromatics extraction was investigated using aqueous solution of sulfolane as the solvent phase and model gasoline, consisting of a benzene, toluene, xylene and hexane mixture, and reformate gasoline as the feed phase. Firstly, the liquid-liquid equilibrium was measured to examine the distribution coefficient and the separation selectivity of aromatics relative to hexane. The distribution coefficients and selectivities of benzene were the highest, followed by those of toluene and xylene. Increased water content of the solvent phase reduced the distribution coefficients and increased the selectivities. The measured equilibria were compared with the results estimated by the UNIFAC method. Countercurrent extraction was conducted, using a packed column with glass Rashig rings as the contactor. The solvent and feed phases were contacted as the continuous and dispersed phases, respectively, and the flow rates of both phases and the water content in the solvent phase were selected as experimental parameters to examine the yield, separation selectivity and volumetric overall mass transfer coefficient. The selectivities for benzene were the highest, followed by toluene and xylene. In the case of extraction from the reformate gasoline with 9 wt％ water content in the solvent phase, the selectivity for benzene was approximately equal to 20, showing higher selectivities for aromatic components. The volumetric overall mass transfer coefficients were mainly affected by the flow rate of the continuous phase and the mass transfer resistance in the continuous phase was the controlling factor in the overall mass transfer resistance.