Question: Program a dynamic simulation for the three-tank mixing system based on the equations derived in Example.
(a) Determine the open-loop responses in the third tank outlet concentration to a step change in
(1) The inlet concentration of component A in stream B (1 to 1.5% A)
(2) The valve position in the A stream (50 to 60% open)
( b) Determine the closed-loop (PID) responses of the third tank outlet concentration to
1) A step set point change.
(2) A disturbance step change in the concentration of component A in stream.
Example: One of the example processes analyzed several times in Part III is the three-tank mixing process in Figure 7.5. This process is selected for its simplicity, which enables us to determine many characteristics of the feedback system, although it is complex enough to exhibit realistic behavior. The process design and model are introduced here; the linearized model is derived; and the selection of variables is discussed.
