EXTRACTCON - Extraction Cascade, Backmixing and Control

6 EXTRACTCON - Extraction Cascade with Backmixing and Control 

In this example of a five-stage extraction column with backmixing, proportional plus integral control of the exit raffinate concentration is to be achieved by regulating solvent flow rate. 

5 Simulation Tools and Examples of Chemical Engineering Processes 

The simulation starts from initially zero concentration conditions along the cascade. Control is implemented from time t =0, in order to obtain an outlet raffinate concentration equal to the controller set point. The program is essentially the same as that used in EQBACK, but with added controller equations. 

Study the response of the system with only proportional control (Tj very large) and determine the resultant steady state offset. Add an increasing degree of integral control and study its effect. 

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