OPTIMUM DISTRIBUTED FEED REACTOR WITH TEMPERATURE CONSTRAINTS

Chemical reactors for a single exothermic reversible reaction with minimum volume for a given duty are considered in which the temperature is controlled directly by bypassing cold feed around a main feed preheater and distributing it along the length of the reactor, and in which the temperature may not exceed a given number: T̄. In general the optimal policy requires that in the first part of the reactor the cold feed be added in such a way that the temperature is maintained equal to T̄, in the second part the rate of addition of cold feed must be such that the reaction rate is maximized with respect to variations of the mass flow rate at each point (of the second part) of the reactor, and in the last part no cold feed must be added at all. A numerical example (the commercial air oxidation of SO2 to SO3) is presented. © 1968.