On the modeling of the kinetics of the selective deactivation of catalysts. Application to the fluidized catalytic cracking process

The deactivation of a solid catalyst may affect in different ways each reaction taking place in a complex network. This creates a variation with time on stream of the product distribution at the reactor exit. To handle data from this common situation, a selective deactivation kinetic model fits the data much better than a nonselective one. Selective deactivation kinetic models are scarcely used because they are often complex and difficult to handle. They also introduce more deactivation kinetic parameters than the nonselective models. Nevertheless, selective deactivation kinetic models are a refinement and are a step forward in the modeling of deactivation kinetics. They might also improve the existing macrokinetic models for commercial reactors. In this paper, several new concepts and ideas are given relating to selective deactivation kinetic models. These concepts are applied to the kinetics of the deactivation of commercial fluidized catalytic cracking catalysts with commercial feedstocks. It is also proven how the kinetics of cracking of the feedstock (heavy oils) is much more affected by the catalyst deactivation than the cracking of the gasoline. A discussion of the results is included.