Extractive distillation of isobutyl alcohol-isobutyl acetate mixture using dimethyl sulfoxide: Process design and intensification

Separation process of isobutyl alcohol and isobutyl acetate mixture is designed using conventional extractive distillation and extractive dividing-wall column (E-DWC) distillation methods. Due to the existence of pressure-sensitive minimum boiling azeotrope in the binary system, thermodynamic analyses based on the NRTL activity coefficient model are carried out. Compared to the atmospheric pressure, operating at vacuum pressures has resulted in less energy consumption when dimethyl sulfoxide (DMSO) is used as the solvent. The distillation column parameters are optimized for economic objective using sensitivity analysis and successive quadratic programming techniques. Environmental performances of the distillation processes are also evaluated. For a product purity of 99.9 mole %, the E-DWC process has resulted in 10.5 % and 9.9 % reductions in the total annual cost and CO2 emission rates respectively compared to the conventional method.