Kinetic study for burning regeneration of coked MFI-type zeolite and numerical modeling for regeneration process in a fixed-bed reactor

Abstract

Kinetic analysis of burning regeneration of coked MFI-type zeolite obtained by catalytic cracking of n-hexane was studied using a multiple-reaction model. Hydrogen contained in the coke was oxidized faster than carbon, and subsequently carbon remaining after the hydrogen combustion was gradually oxidized. Reaction rates of carbon and hydrogen correlated with the Arrhenius equation; and activation energies for the combustion of carbon and hydrogen were 156kJ/mol and 140kJ/mol, respectively, regardless of the coke loading. Regeneration of coked MFI-type zeolite in the fixed-bed reactor was simulated numerically using reaction rates obtained from the kinetic analysis. The numerical result for changes in gas composition with time at the reactor outlet agreed well with the experimental results. Axial distribution of the temperature and concentration of water vapor in the catalyst bed was obtained numerically and results showed that the temperature and water vapor near the outlet were higher than other location in the reactor.