Investigation on the mechanism of adsorption and desorption behavior in cerium ions modified Y-type zeolite and improved hydrocarbons conversion

Different types of Y zeolites（HY, USY and Na Y） containing various amounts of cerium（Ce） were prepared with the method of liquid ion exchange and characterized by X-ray diffraction（XRD）, intelligent gravimetric analyzer（IGA）, and a molecular simulation technology（grand canonical Monte Carlo simulation, GCMC）. A novel calculation method of desorption index（DI） was proposed and the influence of cerium cationic species on the processes of adsorption-desorption of hydrocarbon molecules（n-octane） on the cerium modified Y zeolites（Ce Y） was studied. The results indicated that Ce ion species played a key role in reducing desorption activation energy of n-octane on Y type zeolites, leading to an improvement of the desorption ability of the Ce Y and the regulation of the adsorption state of n-octane from aggregation to decentralization. These findings are essential factors for enhancing the product selectivity of light hydrocarbon component and the catalytic activity of rare earth modified Y zeolites（REY） catalysts in fluid catalytic cracking（FCC） process.