Electronic-structure simulation on hydrocarbon decomposition reaction in FAU zeolite

Abstract

Fluid catalytic cracking (FCC) is a method for obtaining a high value-added component from heavy oil, and uses a zeolite, which is a porous material, as a catalyst. This time, we focused on hydrocarbon decomposition reaction in FCC. We investigated whether this chemical reaction can be reproduced by molecular dynamics calculation by DFTB method. An arbitrary number of Al atoms and H atoms are introduced into the faujasite-type crystal structure, and Bronsted acid points generated by the H atoms and Lewis acid points generated by H2O desorption from the surface are formed on the pore surface. Using the model, the reaction process of hydrocarbon molecules at various temperatures was investigated, and the decomposition reaction proceeded only when the Lewis acid site was included. Moreover, the difference of the decomposition product by reaction temperature was also confirmed. It was found that this decomposition reaction proceeds with the hydride abstraction reaction at the Lewis acid site.