Extractive Distillation Of Ethanol-Methyl Ethyl Ketone System With Ionic Liquids As Extractant And Processing Simulation

Ethanol and methyl ethyl ketone (MEK) are two commonly used industrial organics which form an azeotrope at atmospheric pressure, and therefore they would not be separated by conventional distillation methods when being mixed together. An ionic liquid is a sort of special salt in the liquid state at near-ambient temperature which offers many outstanding properties such as low melting point, negligible volatility, thermal stability, tiny corrosivity, and favorable solvents for a variety of organic and inorganic substances. Distillation extraction experiment using ionic liquids can provide effective guidance to the industry on the solvent selection, operating conditions, energy saving and environmental protection.1. In this paper, the feasibility of two ionic liquids ([MMIM]DMP and [OMIM]BF4) were studied as extractant on the separation of ethanol-MEK system. Isobaric vapor-liquid equilibrium (VLE) data for the ternary mixture of ethanol, MEK and ionic liquids (ILs) were measured at 101.3 kPa with a modified Othmer still. The result showed that the ionic liquids eliminated the azeotropic phenomenon and the relative volatility of ethanol to MEK was altered with the addition of ILs, [MMIM]DMP had stronger separating ability than [OMIM]BF4 at the same concentration.2. The NRTL and eNRTL model was used for fitting the experimental data successfully. Furthermore when compared, the result indicated that the average relative deviation of the activity coefficient was 1.94% and 2.59% for the NRTL model, while they were 3.08% and 4.55% for the eNRTL model ([MMIM]DMP and [OMIM]BF4)3. The extractive distillation experiment separating ethanol and MEK with [MMIM]DMP was carried out. The influnce of different operating conditions on the composition of overhead product was studied. The result showed that when R is 3, [MMIM]DMP was fed at room temperature at the feed rate of 8 mL·min-1, the mass fraction of MEK was up to 99.0%. All the parameters acquired in the experiment would be a theoretical reference for industrial production in the future.4. The parameters regressed with the NRTL model of [MMIM]DMP which had stronger separating ability and more fitting for being used as the extractant was input into the Aspen Plus software. Only one of the operation parameters such as the reflux ratio R, the rate of extractant feed, or the feed position was changed at one time, in order to obtain the optimal position and temperature parameters. The temperature distribution on the plates and the vapor and liquid flow rate were also discussed. The simulation had a close result with the experiment before.