Study Questions

Apply Your Knowledge

An extension of Textbook mixing tank Example 3.1

Modelling Procedure

Assume that the solvent, and component A are contained in separate tanks; sketch the extra equipment which would have to be added to Figure 3.1 in order to achieve the desired value of CA0.



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An extension of Textbook CSTR Example 3.2

System Insight

The dynamic response of a continuous-flow stirred-tank reactor was determined in this example.  Describe the effect on Kp and t when the temperature is increased so that the rate constant, k is doubled.

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An extension of Textbook series CSTRs Example  3.3

System Insight

From the derived model of the two isothermal CSTR reactors in series, which variable CA1 or CA2, responds faster to a step change in CA0.  Why is this the case?



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An extension of Textbook Example 3.4

System Insight

Consider the performance of an on-off residential heating system, in which feedback control is used to monitor and control the temperature.   What would be the effect on the dynamic behavior if:

i.   furniture were added to the room?


ii.  the room were insulated?















An extension of Textbook Example 3.5

Numerical Methods

Consider an isothermal CSTR, with a second order chemical reaction.   Under what scenarios is the linearized model likely to be very accurate?

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An extension of Textbook draining tank level Example 3.6


At first glance, there appears to be an error in Figure 3.14 b.  How can the linearized model predict a negative level in a tank?





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An extension of Textbook Example 3.7

System Insight

In a stirred-tank heat exchanger, what would the effect be on Kp and t if:

i  The tank volume was increased by 50%?

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ii  The flow into the tank was increased by 50%?
















An extension of Textbook Example 3.9

Numerical Methods






To obtain a very accurate numerical solution, should we use a very small Dt? Say for instance 10-8 min.















An extension of exothermic CSTR Example 3.10

System Insight

In exothermic CSTR's, as the temperature increases, the reaction rate increases.  This rise in reaction rate induces an increased conversion of energy from chemical potential to sensible energy. As a result, the temperature increases further.   Given this tendency, why does the temperature reach steady state? 

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