Studies On Vapor-Liquid Equilibria And Liquid-Liquid Equilibria For Ethanol(Isopropanol)-Water-Mixed Solvent

In this thesis, recent progress for the determination, correlationand prediction of vapor-liquid equilibrium (VLE) data and liquid-liquidequilibrium (LLE) data of systems containing alcohol-water-mixedsolvent containing salt, and their distillation application were reviewedin detail.The apparatus and analysis methods for measuring VLE and LLE ofthese systems were set up, VLE data were determined for the systems ofethanol(or isopropanol)-water-six salt added mixed solvents at 101.3kPa.Six mixed solvents containing salts were ethanediol+LiCl, ethanediol+CaCl2, ethanediol+KAc,ethanediol+LiCl+KOH,ethanediol+CaCl2+KOHand ethanediol+KAc+KOH. The systems of VLE studied were classifiedas three types: quasi-ternary system, quaternary system and quinary system.Wilson model, NRTL model, Sander model and modified Mock modelwere used to correlate the VLE data. The experimental results werediscussed and compared. The precisions of correlations by means ofSander model and modified Mock model were better than those ofWilson model and NRTL model. As shown in the experimental results, all of themixed solvents proposed in this thesis could increase obviously the relative volatilitiesof ethanol-water and isopropanol-water ,especially the mixed solvent of containingLiCl .LLE data were determined for the systems of ethanol(or isopropa-nol)-water-2-ethylhexanol at 288.15K,298.15K and 308.15K and the systems ofethanol(or isopropanol) -water-mixed solvent at 298.15K. LLE systemsstudied in this work belong to four components system containing salt, so the LLEdata were correlated by means of the Hand equation. The results of the correlationwere satisfactory. According to the determination of LLE data and correlation results,adding 2-ethylhexanol+NaCl and 2-ethylhexanol+KF could increase obviously the IIdissociation abilities of ethanol-water and isopropanol-water, respectively, especiallyusing 2-ethylhexanol+KF.Different mixed solvents were selected as separating agents and thecontinuous extractive distillation experiments were carried out atdifferent ratios of solvents. High concentration anhydrous ethanol(above 99.5%wt) and isopropanol (above 99.0 %wt) were achieved. Themixed solvent of containing LiCl was a best separating agent.