Optimization of SOx additives of FCC catalysts based on MgO-Al2O3 mixed oxides produced from hydrotalcites

A series of magnesium-rich Mg-Al spinels were prepared from hydrotalcites and characterized. When CeO2 was incorporated they showed a very good SO x absorption as FCC SO x additives, but their regeneration capacity was limited. Different transition metal oxides were tried as co-catalysts, and among them CuO, showed excellent properties to catalyze SO2 oxidation as well as catalyst regeneration. The SO x catalyst was stable when steamed at 750°C together with FCC catalysts.