Case study control of a reactor-condenser process

Conversely, impurity levels should be controlled by varying the flow rate up of the purge stream. up is clearly the only manipulated input available in the model of the slow dynamics (4.35). The rate at which impurity is input to or generated in the process (as captured by the term (d j /dx)gI0(x) x=T-i(()) cannot be set by a process operator and constitutes a (typically unmeasured) process disturbance that the control system must deal with. 

8 Case study control of a reactor-condenser process 

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