Metal-containing spinel composition and process of using same

In a hydrocarbon conversion process for converting a sulfur-containing hydrocarbon feedstock which comprises (1) contacting said feedstock with solid particles capable of promoting the conversion of said feedstock at hydrocarbon conversion conditions in at least one reaction zone to produce at least one hydrocarbon product and to cause deactivating sulfur-containing carbonaceous material to be formed on said solid particles thereby forming deposit-containing particles;

• (2) contacting said deposit-containing particles with an oxygen-containing vaporous medium at conditions to combust at least a portion of said carbonaceous deposit material in at least one regeneration zone to thereby regenerate at least a portion of the hydrocarbon conversion catalytic activity of said solid particles and to form a regeneration zone flue gas containing either sulfur oxide or nitrogen oxide or both;
• and (3) repeating steps (1) and (2) periodically, the improvement which compries, using, in intimate admixture with said solid particles, discrete entities having a chemical make-up different from said solid particles and comprising at least one metal-containing spinel including a first metal and a second metal having a valence higher than the valence of said first metal, at least one component of a third metal other than said first and second metals effective to promote the oxidation of sulfur dioxide to sulfur trioxide at sulfur dioxide oxidation conditions, and at least one component of a fourth metal other than said first, second and third metals effective to promote the reduction of a sulfate of the first metal at first metal sulfate reduction conditions, wherein said third metal is selected from the group consisting of Group IB metals, Group IIB metals, Group VIA metals, the rare earth metals, the Platinum Group metals and mixtures thereof, and said fourth metal is selected from the group consisting of iron, nickel, titanium, chromium, magnanese, cobalt, germanium, tin, bismuth, molybdenum, antimony, vanadium and mixtures thereof and, wherein said third metal component and said fourth metal component are present in amounts effective to promote the oxidation of SO.sub.2 to SO.sub.3 and the subsequent reduction of the sulfate of the first metal formed by reaction with the metal-containing spinel, to H.sub.2 S and the original spinel and in amounts effective to promote the reduction of nitrogen oxides at nitrogen oxide reduction conditions, said discrete entities being present in an amount sufficient to reduce the amount of sulfur oxides or nitrogen oxides in said flue gas.