Modeling and control of an exothermal reaction

• Model for a exothermic catalytic hydrogenation in a slurry batch reactor.
• A gain-scheduling approach improved the performance of the reactor.
• Controller-scheduling significantly improved the performance index.
• The system performance was shown to be limited by cooling system.

A generic cascade control for an exothermic catalytic hydrogenation reaction carried-out in a batch reactor has been studied using a lab-scale multi-phase reactor. The hydrogenation reaction is carried out in a three-phase slurry reactor, which is heated/cooled using oil circulating through an oil bath; additional coils are used for circulating refrigerating water. A series of tests was conducted to obtain the experimental physico-chemical parameters of the system which were then used on the modeling of the system, not only when using the controller from the oil bath but also for the study of the different control strategies. In the work we concluded that, although the system’s performance is limited by the heat exchange capacity, a gain-schedule control strategy is capable of improving the overall performance with an IAE error decrease of 40% and 20% of the overshooting temperature in relation to a single PID controller.