Studies On The Process Of Extractive Distillation With Salt For Alcohol-Water System

Vapor-liquid equilibrium data were determined for the systems of ethanol-water-mixe-d solvents, 1-propanol-water-mixed solvents and 2-propanol-water-mixed solvents at 101.3 kPa and three solvent/feed ratios. The solvent/feed ratios were 0.5:1,1:1 and 2:1.Two mixed solvents containing salts were ethanediol+lithium chloride and ethanediol+postassium acetate. Salt concentration in mixed solvents was 0.2g/ml ethanediol.Wilson model and N-RTL model were used to correlate the vapor-liquid equilibrium data as ternary systems. Proper thermodynamics models for alcohol-water-ethanediol+salt systems were then obtain-ed.As shown as the experimental and correlation results, all of the mixed solvents proposed in this thesis could increase the relative volatilities obviously.The simulation based on equilibrium model was applied in the extractive distillation with salt.The rigorous fractionation RadFrac and Wilson model were chosen in the simulation.The effects of feed stage number,solvent/reflux ratio and reflux ratio on concentration of product were investigated,and concentration distribution for vapor and liquid in the column were simulated.The study on the whole process of extractive distillation with salt was carried out in a laboratory column to produce purity alcohol,and the effects of concentration of postassium acetate in solvent, solvent/reflux ratio and reflux ratio on concentration of product were studied.The experiment results proved that laboratory data was consistent with the simulation results. The separation of the azeotropic mixture of alcohol and water in an industrial scale column was tested, which produced purity alcohol successfully by using extractive distillation with postassium acetate.