Chapter 5

Distillation Control
Strategies
The strategy of distillation control is open to many creative
approaches because there are five or six main variables to
manipulate and many possibilities for cascade, feed-forward
ratios, and model-based computer control as well as conventional feedback control.
Learning Objectives
When you have completed this chapter, you should be able to
1. Understand the four basic distillation control strategies
2. Consider more than one way to control a distillation column
3. Conceptualize the simultaneous control of separation
power base with steam/feed ratio or reflux/feed ratio and
the material balance split with a temperature controller
4. Look at the reflux and distillate flow rates and select the
larger stream flow rate to manipulate for level control and
the smaller stream for temperature control if steam/feed
ratio is being used for the separation power base
33