Dynamic simulation of a reactive distillation process for n-butyl acetate production using CHEMCAD

The dynamic simulation of a reactive distillation process developed with the aid of CHEMCAD for the production of n-butyl acetate has been carried out in this research work. Originally, the by-product of the process was water. The developed model of the system was first simulated for steady state using a reflux ratio of 3 and a reboiler duty of 1.4 kW in order to have initial values for the mole fractions of the components involved. The model was converted to a dynamic type by activating the "Dynamics" in the "Convergence" tab of the "Run" menu of CHEMCAD. The dynamic model of the system was run using different (positive and negative) step changes applied to the input variables, which were reflux ratio and reboiler duty, of the process. The results obtained from the steady-state simulation showed that only n-butyl acetate and unconverted acetic acid were existing in the reboiler section of the column initially. The dynamic simulation of the process showed that the system was a stable one because it could get settled after some running time of its dynamic model for all the step changes in the two input variables considered. It was also discovered from the simulations carried out that the dynamic responses of the system to negative step changes in reflux ratio were smoother than those obtained when positive step changes were applied to the same input variable. Moreover, the applications of negative step changes to the reboiler duty resulted in decreases in the mole fractions of n-butyl acetate present in the bottom section of the column while the applications of positive changes to the same reboiler duty gave rise to increases in the mole fraction values of the desired product that was collected through the reboiler section of the column. It was discovered from the results obtained that the higher the reboiler duty of the system that was applied in the production of n-butyl acetate from the esterification reaction involving acetic acid and n-butanol, the faster the system was approaching its dynamic steady state. © 2017 Trans Tech Publications, Switzerland.