Optimization Strategies in a Fixed-Bed Reactor for HCl Oxidation

Heterocatalytic oxidation of HCl into Cl-2 (HCl conversion process) over a CeO2 CuO catalyst in a fixed-bed reactor has been optimized using four different objective functions and three different methods. For a given residence time, the HCl conversion could be maximized in various reactor configurations, namely with the application of a graded catalyst bed, with partitioning the reactor shell and using multistage temperature control, or with the combination of both methods. However, as the obtained temperature profiles differed considerably from each other, we considered three objective functions in order to smooth the reactor temperature profile. These implement a nonconventional approach since the proposed objective functions aim to deal directly with the temperature changes and HCl conversion is only taken into consideration as a nonlinear constraint. The different results from each method and objective function were compared using the apparent temperature gradients along the length of the reactor. The results show that reasonably low temperature gradients and a relatively smooth temperature profile can be achieved that also indirectly contributes to the stability of both the reactor and the catalyst.