Process Flowsheets

In this section we attempt to generate a flowsheet for high purity acetates using the combination of a stripper, a rectifier, a reactive section, and possibly a decanter. The objective is to devise hybrid reactive distillation systems to produce commercial grade acetates. Figure 7.2 provides possible flowsheets for esterification systems.

7.2.1 Type I Flowsheet: MeAc

In reactive distillation the heavy reactant is typically fed from the top of the reactive section and the light reactant goes into the bottom part of the reactive zone. For the methyl acetate system, the heavy reactant is the acid (HAc) and the light reactant is the alcohol (MeOH). If the reactive zone consumes all of the acid, we are dealing with the separation of H2O/ MeOH/MeAc, an almost ternary system, in the stripping section. The RCM of Figure 7.3a indicates that the separation will lead to the pure H2O node toward the bottom of the column. In contrast, if we react away most of the alcohol toward the top section of the reactive zone, in the rectifying section we are separating HAc/MeAc with a small amount of H2O. Again, the RCM in Figure 7.3a shows that it is possible to obtain relatively high purity MeAc, despite being a saddle in the RCM notation. This is

8L. H. Horsley, Azeotropic Data—III, Advances in Chemistry Series No. 116, American Chemical Society, Washington, D.C., 1973.


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