Repetitive control and online optimization of Catofin propane process

The Catofin propane process is an emerging industrial process for propylene production through dehydrogenation of propane. It is composed of multiple adiabatic fixed-bed reactors which undergo cyclic operations where propane dehydrogenation and catalyst regeneration alternate over roughly 10-min period for each. One of the major concerns in the operation of the Catofin process is maintaining the reactor at an optimum condition while overcoming gradual catalyst deactivation. Addressing this issue, an online optimization of the Catofin process combined with a repetitive control has been investigated. The optimizer computes optimum initial bed temperatures for dehydrogenation and optimum air flow rate for regeneration, and the repetitive controller performs cycle-wise feedback action during regeneration to attain the target bed temperatures at the terminal time of the regeneration period. Numerical studies have shown that the proposed online optimizing control system performs satisfactorily coping with the catalyst deactivation and other disturbances.