Type II Flowsheet EtAc and IPAc

The boiling point temperature ranking suggest that we may use the type I flowsheet for EtAc production with EtAc and H2O withdrawn from the top and the bottom of the column. Indeed, this configuration was simulated by several researchers, but the purity level 

Doherty and M. F. Malone, Conceptual Design of Distillation Systems, McGraw-Hill, New York, 2001. M. A. Al-Arfaj and W. L. Luyhen, Comparative control smdy of ideal and methyl acetate reactive distillation, Chem. Eng. Sci. 57, 5039-5050 (2002). 

Vora and P. Daoutidis, Dynamic and control of an ethyl acetate reactive distillation column, Ind. Eng. Chem. Res. 40, 833 -849 (2001). 

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Multiplicity analysis indicates that composition control of the MeAc system can be difficult, and this is also true for the AmAc system in which the input multiplicity cannot be completely eliminated. As for the type II flowsheets (EtAc and IPAc), the input multiplicity can be overcome by using the temperamre control as shown in Figure 13.3. Similar to the previous analysis, the BuAc system does not show any potential problem in control. 

For the type II flowsheets (EtAc and IPAc), a stripper temperature is maintained using the heat input to the stripper and a temperature in the reactive distillation column is controlled using the ratio of fresh feeds into the reactive distUIation column (i.e., 7str,3-Qr,s 7 futc,i5 FR for EtAc, 7str,3—7rdc,i8 FR for IPAc). 

The type II flowsheet (EtAc and IPAc) was divided into two units separated by a large decanter. This somewhat dampened disturbances and interactions between the reactive distillation column and the stripper, which subsequently led to a more eontrollable process. The flowsheets (BuAc and AmAc) had decanters that provided a natural one-end composition control via LL equilibrium. Interaction between top and bottoms composition control was therefore reduced. 

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