Feed-forward and ratio control

FEED-FORWARD AND RATIO CONTROL 7.14.1. Food-forward Control 

This is also termed predictive control and can be usefully employed where there are significant time lags between a load change and its subsequent effect upon a system output variable. A typical example is the response of the composition xD of the overhead product stream of a distillation process to a perturbation in feed 

Block diagrams of cascade control system shown in Fig. 7.66 (a) original block diagram (b) condensed block diagram 

An composition snslytsr FRC flow rocordor controller TRC tsmpsralurs rscordor controllsr LIC lovol Indicator controllsr PIC prsssura indicator controllsr 

Feed-forward control of the composition of the overhead product stream of a distillation column where feed composition is the only load variable 

---