Separation Of Binary Azeotrope Acetonitrile And1-propanol By Extractive Distillation

Acetonitrile and1-propanol are widely used as solvents in the fine chemical andpharmaceutical industry and so on. There are a lot of acetonitrile and1-propanolmixture in industry, and acetonitrile and1-propanol form a minimum azeotrope atatmospheric pressure, high concentration of acetonitrile can not be obtained byconventional distillation. Separation of binary azeotrope acetonitrile and1-propanolby extractive distillation using N-methyl pyrrolidone as the solvent was studied in thispaper.Firstly, glycol, N-methyl pyrrolidone, glycerol, DMF, DMSO were selected aspre-selected solvents qualitative rules. Then N-methyl pyrrolidone was selected asproper solvent through quantitative calculation by UNIFAC group contributionmethod. The validity of the solvent N-methyl pyrrolidone was verified through thevapor-liquid equilibrium experiments, acetonitrile and1-propanol vapor-liquidequilibrium diagram was made.The simulation of batch extractive distillation of binary azeotrope acetonitrileand1-propanol was made by ChemCAD. Tower temperature distribution curve, thevapor and liquid flow distribution curve and the concentration distribution curve weregot through the simulation of batch extractive distillation. Concentration curves ofdistillate vs. time, Concentration curves of accumulator vs. time, and Concentrationcurves of pot residue vs. time were also obtained through simulation.The continuous extractive distillation simulation of binary azeotrope acetonitrileand1-propanol was made by Aspen Plus. The extractive distillation column refluxratio, solvent ratio, raw material feed location and solvent feed location have beendetermined using sensitivity analysis functions, tower temperature distribution curve,the vapor and liquid flow distribution curve and the concentration distribution curvewere got through the simulation. The extractive distillation column reflux ratio was1.2, the solvent ratio was1:1, the raw material feed location was the25th tray, and thesolvent feed location was the3rd tray after sensitivity analysis, the light componentacetonitrile concentration in the top was more than99%. The solvent recovery columnreflux ratio was1, the number of trays was7, feed location was the3rd tray, and the solvent mass fraction in the bottom was up to99%after sensitivity analysis.The batch extractive distillation experiments were done to separate the binaryazeotrope acetonitrile and1-propanol. The hydrodynamic parameters of the batchdistillation column were determined, the tower operating pressure drop was200-300Pa, and the number of theoretical plates of distillation column was28. Batchextractive distillation experiments were made in different solvent flow rate to meet theseparation requirements. The batch extractive distillation experiments results agreedwith the simulation results.