Abstract: A process for reducing sulfur oxides production during an FCC cracking operation comprises the steps of:(a) passivating metal contaminants on an FCC catalyst by contacting the FCC catalyst with a sulfur-containing compound under conditions that enable association of the sulfur with the metal contaminants;(b) cracking hydrocarbons with the passivated FCC catalyst in an FCC cracking zone;(c) oxidatively regenerating the catalyst in a regeneration zone whereby the carbonaceous material deposited on the catalyst in step (b) is burned off and the sulfur deposited on the FCC catalyst in step (a) is converted to sulfur oxides;(d) reacting the sulfur oxides with a sulfur oxide adsorption additive capable of adsorbing the sulfur oxides under sulfur oxide adsorbing conditions;(e) converting the adsorbed sulfur oxides from step (d) to hydrogen sulfide by contacting the adsorbed sulfur oxides in a separate treatment vessel with a reducing gas before the regenerated FCC catalyst and sulfur oxides adsorption additive enter

Abstract: A process for regeneration of cracking catalyst while minimizing NO.sub.x emissions is disclosed. A zinc-based DeNO.sub.x catalyst is present in an amount and in a form which reduces NO.sub.x emissions. Relatively small amounts of zinc oxides impregnated on a separate support having little or no cracking activity are preferred. The zinc NO.sub.x reduction catalyst can be a separate particle additive, or can be made in situ by adding a solution or dispersion of zinc or a compound thereof to the cracking unit, or to the hydrocarbon feed to the cracking unit.

Abstract: A process for regeneration of cracking catalyst while minimizing NO.sub.x emissions is disclosed. A DeNOx additive is present in an amount and in a form which reduces NO.sub.x emissions, but does not passivate metals (such as Ni and V) deposited on the catalyst during the cracking reaction nor CO combustion promoter which may be present. Relatively small amounts of antimony oxides impregnated on a separate support having little or no cracking activity are preferred.

Abstract: A known method for passivating contaminant metals on an FCC catalyst comprises treating the catalyst with a sufficient amount of a sulfur-containing compound capable of associating with the contaminant metals when in contact therewith. An improvement comprises contacting the catalyst with the sulfur-containing compound for at least 3 seconds. In another embodiment of the invention, the improvement comprises contacting the catalyst with the sulfur-containing compound in a separate treatment vessel.

Abstract: Oxides of nitrogen (NO.sub.x) emissions are catalytically reduced by contacting a flue gas containing NO.sub.x with ammonia or an ammonia precursor in the presence of a catalyst effective for promoting the reduction of NO.sub.x with ammonia in oxidizing atmospheres, such as those in FCC catalyst regenerators. Bismuth oxides on a support are the preferred NO.sub.x reduction catalyst. The process is especially useful in reducing NO.sub.x emissions from fluidized catalytic cracking units.

Abstract: An improved composition and method for passivating vanadium on or in a catalytic cracking catalyst during the process of catalytic cracking of hydrocarbons is described. The improved method comprises mixing discrete particles of lanthanum oxide and, optionally, other rare earth oxides along with the catalyst and the hydrocarbon during the catalytic cracking process.

Abstract: A catalytic cracking process especially useful for the catalytic cracking of high metals content feeds including resids in which the feed is cracked in the presence of a catalyst additive comprising a dehydrated magnesium-aluminum hydrotalcite which acts as a trap for vanadium as well as an agent for reducing the content of sulfur oxides in the regenerator flue gas. The additive is used in the form of a separate additive from the cracking catalyst particles in order to keep the vanadium away from the cracking catalyst and so preserve the activity of the catalyst.