Experimental Studies On Extractive Distillation Of Craked C5 Compounds

With a high content of compounds as raw materials for the rubber synthesis industry such as isoprene, the cracked C5 fraction of crude oil is a promising source of isoprene production. The components in C5 fraction has a close range of boiling points and forms a series of azeotropes. Therefore, extractive distillation is a more suitable, effective way for C5 separation than ordinary distillation.The first part of this thesis gives an introduction about the role of the extractant in extractive distillation and the criteria of choosing a good extractant as well as the recent progress in C5 separation. In the experimental part, N-methyl pyrrolidone (NMP) was selected as the main extractant for C5 separation. Optimization of the composition of mixed solvent was achieved on a QY-2 Vapor-Liquid Equilibrium apparatus.Continuous extractive distillation was performed with the optimized mixed solvent. The effect of reflux ratio and solvent ratio on separation result was studied and the isoprene product was obtained.The vapor-liquid equilibrium data of isoprene-NMP, pentane-NMP, 2-methyl-2-butyl butane-NMP, cyclopentane-NMP, cyclopentene-NMP, isoprene-1,4-dioxane and pentane-1,4-dioxane was also determined on a QY-2 Vapor-Liquid Equilibrium apparatus. Thermodynamic consistency test and correlation of the data with Wilson, NRTL and UNIQUAC equations give satisfying results. The data provided the VLE data of binary systems of C5 hydrocarbon-NMP and 1,4-dioxane and can provide some basic information for process development.