Simultaneous estimation of kinetics and catalysts activity during cracking of 1,3,5-tri-isopropyl benzene on FCC catalyst

Abstract

Catalytic cracking reactions, performed on commercial catalysts, are difficult to follow because of the simultaneous deactivation of the catalyst as consequence of coke deposition on catalyst surfaces during cracking of hydrocarbon molecules. In this work, a model for catalyst deactivation in terms of fouling because of blockage of micropores of the catalyst is used to estimate activity independently of reaction rates; later cracking kinetic rates of a model compound are estimated. It was found that the expected low energy of coke deposition reactions dominate the process, however these reactions are not easy to estimate a priori because of the definition of coke as a lumped entity. A comprehensive model of a CREC-Riser simulator Reactor is developed in order to consider mass balances for each specific operating condition. Three temperatures and two contact times are used to evaluate frequency factors and activation energies of the reactions that take place during the catalytic cracking of 1,3,5-tri-isopropyl benzene in two cases, with catalyst coming from an industrial unit and with catalyst pre-coked in laboratory. A methodology to separate activity and apparent kinetics in this kind of reactions is proposed.