Characteristics and kinetics of steam-gasification regeneration for Coked FCC catalyst in a micro-fluidized bed reactor

The characteristics and kinetics of steam gasification regeneration were investigated for two kinds of coked fluid catalytic cracking (FCC) catalysts (i.e., Coked FCC-1 and Coked FCC-2) in a micro-fluidized bed reactor analyzer (MFBRA). FCC-1 was a commercial catalyst from the industrial FCC process, while FCC-2 was specially designed with both catalytic effects of heavy oil cracking and coke gasification. Coke on the two catalysts was gasified with steam at different temperatures to investigate its reaction behavior and kinetics. The results showed that the produced gas from steam gasification of the deposited carbon on the catalyst contained above 70 % volume fraction of H2 and CO. Gasification rate first increased and then slowly decreased with the increase of carbon conversion. In comparison with coked FCC-1 catalyst, the time required for regenerating coked FCC-2 was shortened by more than 30%, as result of adding alkaline metal oxides to it and adjusting its pore sizes. Both homogenous model (HM) and shrinking core model (SCM) were used to correlate the steam gasification behavior and kinetic parameters of deposited coke, indicating that the HM allowed better fitting for the experimental data. The activation energy for the coke gasification on FCC-2 was 116.2 kJ/mol, lower than that of FCC-1 (151.4 kJ/mol), which verified that the coked FCC-2 was easier to be regenerated by steam gasification. ©, 2014, Science Press. All right reserved.