Abstract: An improved process for converting hydrocarbons using a catalyst which is periodically regenerated to remove carbonaceous deposits, the catalyst being comprised of a mixture containing, as a major component, solid particles capable of promoting hydrocarbon conversion at hydrocarbon conversion conditions, and, as a minor component, discrete entities comprising at least one spinel, including a first metal and at least two different second metals having valences higher than the valence of the first metal, one of the second metals being aluminum and the other of the second metals being trivalent and selected from the group consisting of iron, chromium, vanadium, manganese, gallium, boron, cobalt and mixtures thereof; thereby reducing the amount of sulfur oxides exiting the catalyst regeneration zone.Improved hydrocarbon conversion catalysts are also disclosed.

Abstract: Disclosed is a hydrocarbon conversion process in which solid particles capable of promoting the conversion of a sulfur-containing hydrocarbon feedstock in intimate admixture with a minor amount of discrete entities effective to reduce atmospheric emissions of sulfur oxides from the process are circulated between at least one reaction zone wherein sulfur-containing deposits are formed on the solid particles, and at least one regeneration zone wherein at least a portion of the deposits is removed from the solid particles to produce regenerated solid particles which are circulated to the reaction zone and sulfur oxides; and the discrete entities are capable of associating with sulfur trioxide in the regeneration zone and of disassociating with sulfur trioxide in the reaction zone. The improvement comprises contacting the regenerated solid particles and discrete entities with at least one gaseous reducing medium prior to the solid particles and discrete entities entering the reaction zone.