(53c) Effect of Vanadium Deposited Locations in FCC Catalyst on Naphtha Sulfur Content

Recently, the positive effect of deposited vanadium on reducing FCC naphtha sulfur content has been gradually realized and come to be affirmed during FCC process. So the appropriate method by adding vanadium oxide in FCC catalyst was investigated in this work. Through the comparing of different vanadium deposited locations on FCC catalyst such as pseudoboehmite (converted to γ-Al₂O₃ after calcinated), clay and Y zeolite, it was found that the interaction between vanadium oxide and its supports can induce new active sites such as Lewis acid sites with proper acid strength and V-O-M (support) bond with active oxygen. The former benefits the selective adsorption of thiophene in the presence of cyclohexane while the latter benefits the oxidation of thiophene to SO₂. Through the evaluation by MAT test using sulfur contained VGO feedstock, it has shown that deposited 1000 µg/g V⁵⁺ on different component of FCC catalyst will achieve sulfur reduction effect in different extent comparing at the same heavy oil conversion. Vanadium oxide supported on zeolite is the best while on γ-Al₂O₃ is inferior.