The process with two series chemical reactors in Example 3.3 is considered in this question. The process flexibility is increased by allowing the temperatures of the two reactors to be manipulated independently. The two controlled variables are the concentrations of reactant A in the two reactors. The rate constant can be expressed as 5.87 x io5g-5000/r (with temperature in K, and the disturbance is feed composition, C_AD

(a) Determine whether the input-output combination is controllable.

(b) Determine whether either loop pairing can be eliminated based on the signs of the relative gains.

(c) Determine whether decoupling could improve the dynamic performance, especially if the most important controlled variable is the con centration in the second reactor

EXAMPLE 3.3

Two isothermal CSTR reactors A problem similar to the single CSTR is presented, with the only difference that two series reactors are included as shown in Figure 3.6. Each tank is one-half the volume of the tank .