A flow reactor, also known as a continuous reactor, is a vessel that holds an open reacting system within its confines while the reactants chemically transform into products. Since the reacting system is open, there is continuous entry of material into the vessel as well as continuous exit of material out of the vessel. To sum up, a flow reactor is a vessel in which reactants are continuously fed and products are continuously taken out. The reactants chemically transform into products while they flow through the reactor. Most industrial reactors are of the continuous type as they require lower operational cost compared to batch reactors. They are suited for large-scale operations owing to better economies of scale. An ideal flow reactor is one in which the flow of material (fluid) through the reactor can be modeled as one of the two ideal flow patterns (Levenspiel and Bischoff, 1963), namely plug flow or complete backmix flow. Further, an isothermal flow reactor has constant temperature both with respect to time as well as with respect to position within the reactor. These ideal conditions may be approximated but not rigorously met in a real flow reactor. Nevertheless, the study of the hypothetical idealized system provides vital understanding that can be used for the real systems as well.