Authors: Rohan Shorey
Comments: 4 Pages, 6 figures, 2 tables, a comparative study
In the present study, a distillation process to separate methanol-water was simulated. The work employed NRTL activity coefficients model to describe the vapor-liquid equilibrium of the methanol-water system. The main extractive column took a mixture of methanol and water as feed and separated methanol as distillate and water as the bottoms product. The simulations were performed on DWSIM and ASPEN Plus version 8.6, thus, this is a comparative study with the prime focus to gain an insight of the obstacles faced in simulations carried out on an open source software. The initial work consisted of simulation of the process using shortcut method, so as to obtain basic sizing of the columns based on the purity required and to obtain data to study the variation of reflux ratio with the number of stages and thus, to finalize the actual number of stages required and reflux ratio for rigorous model. Further, rigorous models were employed so as to get more accurate results using the values obtained earlier. A distillate of substantially pure methanol stream with minimal water was obtained using the above model. Finally, a variation of the composition of methanol and water with the stages of distillation column were plotted and also, T-x-y and P-x-y plots were generated.