Page 405 - Analysis, Synthesis and Design of Chemical Processes, Third Edition

22. The residue curve map of Figure 12.9(a) shows that batch distillation of a mixture at the azeotropic
composition for the system (A+B) with a small amount of C added will result in a very pure liquid C
residue in the still. Is this a good separation unit choice to obtain “pure” C? Analyze the advantages
and disadvantages.

On a residue curve map, will the composition of a ternary, minimum-boiling azeotrope always be a
23.
stable node, an unstable node, a saddle point, or none of the above?

As noted in Section 12.1.1, laboratory studies often involve batch or semibatch reactors for
24. convenience. Develop four heuristics for choosing whether to use batch, semibatch, or continuous
reactors for the commercial plant.

Semibatch or batch reactors are common in biochemical operations. What characteristics of
biological systems, materials, and products lead to the choice of batch over continuous reactors? To
what extent do these characteristics also lead to unsteady operations of other GBFD sections:

a. Reactor feed preparation

25. b. Separator feed preparation

c. Separator

d. Recycle

e. Environmental control

The unique characteristics of an azeotrope make it ideal for some applications. Find three
applications of azeotropic products. How is the production of an azeotropic composition different
26.
from the production of “pure” A and B when (A+B) forms an azeotrope? Does the process differ for
a minimum-boiling and a maximum-boiling azeotrope?

For biological systems (which often have a very narrow range of acceptable temperatures), describe
27.
the advantages and disadvantages of large and small ΔT’s in reactor temperature control systems.

Biological systems often require sterilization as a step before inoculation with the appropriate
microbial culture. Sterilization can be considered a reaction process in which organisms are killed,
often through cell lysis, using thermal or chemical routes. Consider both batch and continuous
28.
sterilization. Which has advantages for sterilizing process equipment? Which has advantages for
sterilizing reactor feedstock? (Note: For some biochemical processes, sterilization is neither
required not desired, e.g., waste treatment.)