(357c) Dynamic Modeling to Study Reversible Poisoning of a Catalytic Bed

Catalyst poisoning in tubular reactors is a common problem in many chemical processes using a variety of catalysts including zeolites, and transition metals. A theoretical model that can help describe the reversible deactivation phenomena accurately can help manage the plant and optimize reactor throughput. In this work, we present a detailed dynamic model used to describe the activation and deactivation cycles in a catalytic reactor used for a common exothermic reaction.

It was observed that a trace impurity (such as ammonia found in ppm level) decreases the active life of the catalyst bed considerably. As the catalyst bed deactivates, the peak temperature moves down the bed rendering the initial part of the bed incapable of participating in the reaction. After the overall conversion drops significantly, the bed can regenerated by steam stripping the ammonia. These phenomena have been simulated using a dynamic model. All the parameters were estimated independently based on a variety of laboratory measurements.