Abstract
Hydrotalcite-derived Mg,Al-mixed oxides (MO) with variable Mg/Al ratios (3, 1, 1/3) were impregnated with 17 wt.% of CeO 2 and evaluated for SO x removal under conditions similar to those of FCC units. The catalyst with Mg/Al = 1, for which both an Mg(Al)O periclase-type and an MgAl 2O 4-spinel were present before sulfation, showed the best performance for both SO x uptake and catalyst regeneration. The results from TPR/MS and XRD along reduction indicate the existence of different species in the sulfated samples. The reduction of these sulfate species leads to the evolution of SO 2 or H 2S, Mg(Al)O being the solid product in any case. Our results do not support the assertion that the reduction of S 6+ to S 2− is a consecutive reaction. The evolution of SO 2 upon reduction decreases as the relative importance of the spinel-phase in the mixed oxides increases. The sulfates formed from the spinel-phase are more easily reduced than those from the periclase phase. The growth of the sulfate phase in the early stages of sulfation destroys the small mesopores of the mixed oxide. Upon regeneration, the sulfate phase is consumed and larger mesopores are formed.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
