Nonisothermal Stirred-Tank Reactor with Irreversible Exothermic Reaction A → B: 1. Modeling and Local Control.

In this chapter, the nonlinear and linear mathematical model of a CSTR where an irreversible exothermic reaction takes place is considered. From the analysis of the steady states, the curves of removed and generated heat are deduced in order to determine the equilibrium point and the transfer function of the reactor. Considering a set of reactors ranging from small to high volume, it is shown that the open-loop transfer function can be conditionally stable, and the effect of the scaling-up is investigated by means of the root locus. Reactor and jacket equilibrium temperatures vs. reactor volume are deduced in order to obtain an intuitive notion of the reactor controllability. The problem of the local control of a single loop concentration and cascade temperature control from the linearized model previously considered is analyzed by using PI controllers. Several examples considering step responses to changes in the concentration and temperature references are considered. Finally, the decoupling and the feedback control of the reactor by using the pole-placement technique have been also considered. [ABSTRACT FROM AUTHOR]