Modeling of coke formation and deactivation in a fluid catalytic cracking unit

In this paper we describe a new model of the catalyst deactivation due to riser reactions in the FCCU. Instead of considering other authors' approaches in which all the coke is usually modelled in a uniform way, we distinguish different kinds of coke and we propose a new coke raising model starting from the oil feed properties. Thereafter, we analyse different deactivation kinetic equations, and we propose a new one. it describes the catalyst reaction in relation with coke, instead of studying it in relation with time, which is the approach conventionally taken. Even considering easier to develop models in which deactivation is studied along time, our model is more flexible and intuitive, closer to the actual catalyst behaviour, allowing the simulation of special situations, such as those in which the catalyst is partially regenerated.