Dynamic Performance of CS7-RR

There are two reasons for the improvement in control. The first has already been discussed the elimination of inverse response. The second is equally important the two temperature controllers in the CS7-RR structure have the same action (direct). This means that when both control loops see a positive vapor boilup disturbance, which increases both tray temperatures, the two controllers will increase both fresh feeds. This helps to maintain the delicate stoichiometric balance between the reactants that is essential for neat operation of a reactive distillation column. Because a reactive distillation column acts like a pure integrator with respect to the reactants, this similar initial response is very important for CS7-RR, where feedstreams are used as manipulated variables. 

Conversely, a negative change in Vs causes a decrease in both temperatures, which results in an initial decrease in both fiesh feed flowrates Foa and ob- This keeps the stoichiometric ratio close to the original value and prevents a breakthrough of reactants. Thus, 

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