| The solvent selection for extractive distillation and the effects of different operation parameters on batch extractive distillation process were studied via theoretical analysis, experiments and simulation.The solvent selection for close boiling isomers separated by extractive distillation was studied in this paper. According to empirical method, several solvents were selected for the systems of trans-4-methylcyclohexylamine - cis-4-methylcyclohexyl- amine and 2,5-dimethylpyrazine - 2,6-dimethypyrazine, and verified by the vapor -liquid equilibria experiments. The solvents with relatively large solvent selectivity for trans-4-methylcyclohexylamine - cis-4-methylcyclohexylamine and 2,5-dimethyl- pyrazine - 2,6-dimethypyrazine are, respectively, ethylene glycol and phenol. The separation of ethylenediamine - N-ethylethylenediamine by batch extractive distillation were studied.β-phenylethyl alcohol and ethylene glycol were selected as candidate solvents by group contribution method and empirical method respectively.The vapor-liquid equilibria for binary mixtures of ethylenediamine - N-ethylethylene- diamine, ethylenediamine - ethylene glycol and N-ethylethylenediamine - ethylene glycol were obtained by the vapor-liquid equilibria experiments .The parameters of Wilson model for these binary systems were correlated by the experimental data. The vapor-liquid equilibrium of ethylenediamine - N-ethylethylenediamine in ethylene glycol andβ-phenylethyl alcohol were calculated and verified by experiments. It is proved that ethylene glycol was the effective solvent rather thanβ-phenylethyl alcohol for the separation of ethylenediamine - N-ethylethylenediamine by extractive distillation. If ethylene glycol is used as the solvent, the relative volatility of ethylenediamine - N-ethylethylenediamine mixture is reversed, and N-ethylethylene- diamine is changed to be the light component. The batch extractive distillation experiments for separation of ethylenediamine - N-ethylethylenediamine were carried out, and the effects of the solvents selected above in such process were investigated.The comprehensive model of batch extractive distillation was established and solved by two-point implicit method. The effects of operation parameters such as solvent ratio, reflux ratio, temperature of the solvent feed and solvent concentration in the original charge on the batch extractive distillation process, were studied by simulation, using the systems of ethylenediamine - N-ethylethylenediamine and acetonitrile - water as examples.
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