On the optimization by boundary control of tubular reactors with catalyst decay

In optimization problems dealing with catalytic reactors, where the catalyst deactivates slowly with time, it is common to assume a quasi steady state in the reaction and deactivation equations. Although the difference in reactor performance, for a given control policy, between the unsteady state reactor and its quasi steady state approximation is usually negligible, a very large difference can exist in the optimal control policy for the two models. For a single irreversible reaction, where the catalyst deactivation is dependent on conversion and where the control variable is the temperature of the fluid entering a tubular reactor, it is shown numerically that the performance of the reactor for a suboptimal control policy can be significantly superior to the optimal performance predicted from a quasi steady state model formulation.