MODELLING, SIMULATION AND CONTROL OF ETHYL ACETATE REACTIVE DISTILLATION COLUMN USING CHEMCAD
Amenaghawon, Nosakhare Andrew 1 and Ogbeide, Samuel. E 2
Department of Chemical Engineering,
University of Benin, Benin City, Nigeria
E-mail: andrew.amenaghawon@uniben.edu /samuelogbeide@gmail.com
ABSTRACT
The modelling, simulation and control of a reactive distillation column for the production of ethyl acetate from acetic acid and ethanol has been studied using commercially available process simulation software, CHEMCAD®. The effects of key operating variables such as reflux ratio, distillate rate, feed tray location and activity model on the composition of ethyl acetate in the distillate at steady state were studied. Steady state simulation results show that if a double feeding strategy is adopted, acetic acid must be fed to the tray 2 while ethanol must be fed to tray 12 in order to obtain optimum composition of ethyl acetate in the liquid phase. Also, a reflux ratio of 12 resulted in optimum composition of ethyl acetate in the liquid phase. Increasing the distillate rate resulted in an increase in the composition of ethyl acetate in the liquid phase. Using the steady state results as an initial state, dynamic simulations were run for the purpose controlling the reboiler pressure and ethyl acetate purity. For pressure control, the Ziegler-Nichols (ZN) tuning method was used to tune the controller parameters resulting in an optimal value of integral square error (ISE)of 587.85 and corresponding values of 0.13 and 7.05 for proportional gain and integral time constant (and ) respectively. A simulation exercise such as presented in this work is very important and is increasingly becoming popular. This is because simulation of mathematical models of chemical processes is safe, cheap and less time demanding. This has also been helped by the development of computers with high computational capabilities.
Keywords; Steady-state, Dynamics, Control, Reactive distillation, Ethyl acetate