Enthalpy Management and Temperature Control

Summary

In the preceeding chapters the rates of chemical reactions were considered for given temperatures, and when integral reactor models were presented (Chapters 3 and 7) the reactors were assumed to be isothermal. Since most chemical reactions are accompanied by large changes in enthalpy, often causing large heat effects, we have two additional problems that are interrelated: how to supply or remove sufficient heat, and how to control the temperature of the reaction medium. We have to deal with this problem at the volume element level and at the level of the reactor. Three different cases of temperature control of reactors are discussed: the well mixed isothermal reactor, the tubular reactor with a controlled temperature gradient, and the semi-batch reactor with a certain temperature profile in time.