T
Feed
T
T
Distillate
Side draw
Bottoms
Figure 5.1 Dividing wall column.
42 ◾  Distillation Control, Optimization, and Tuning
5.7 Distillate Vapor Flow Rate
There are cases where a vapor stream from the top of a distillation column is needed as the distillate. In that case, the
distillate vapor flow rate can be manipulated to control the
column pressure and the condenser can be controlled as a
partial condenser to produce the reflux. The heat duty for
a condenser is a function of the heat transfer surface area
and the temperature difference between the cooling medium
and the condensing vapors. One approach is to recirculate
the cooling fluid and control the temperature of the coolant
for a variable temperature difference between the condensing vapors and the coolant. Another approach can be to use