Extractive Distillation of Ethylbenzene and Styrene using Sulfolane as Solvent: Low Pressure Isobaric VLE Data

The distillation of ethylbenzene (EB) from styrene (SM) is very energy intensive. By using extractive distillation instead, both capital and energy expenses are potentially reduced dramatically. Hereto we propose to use sulfolane (SF) as solvent. Currently there is no ternary vapor liquid equilibrium (VLE) data available of the system SM/EB/SF and the binary VLE data sets of EB/SM available in literature are found to be thermodynamically inconsistent. In this study thermodynamically consistent VLE data is obtained for the three binary systems and the ternary system in the pressure range of 50-200 mbar. Both the Wilson and NRTL model can adequately describe the experimental VLE data. The solvent SF increases the relative volatility significantly from 1.3-1.4 up to 2.3. Equilibrium process modeling suggests that an energy reduction of 50% compared to the traditional distillation process can be obtained with the extractive distillation process