Exxon Research and Engineering Company

Terry A Reid

Elroy M Gladrow

William L Schuette

Gordon Frederick Stuntz

A method for passivating metal contaminants present in a hydrocarbon feedstock which become deposited on cracking catalyst is described. The method is directed at passing the cracking catalyst through a passivation zone having a reducing atmosphere maintained at an elevated temperature by the introduction of a process reducing gas. The unsaturated hydrocarbon content of the reducing gas is decreased prior to the introduction of the process reducing gas into the passivation zone to thereby lower the rate of coke formation. In a preferred embodiment process reducing gas is passed through a hydrogenation zone adapted to hydrogenate an unsaturated hydrocarbon present in the process reducing gas prior to the process reducing gas being added to the passivation zone.

Passivation of metal contaminants in cat cracking

An improved catalyst, and process utilizing said catalyst for catalytically cracking a sulfur-containing hydrocarbon feed, and for the fixation of sulfur by the catalyst and transfer thereof from the catalyst regeneration zone to the reaction zone of a catalytic cracking unit. The catalyst comprises an admixture of composite particles, one present in major concentration for providing principally cracking and combustion promoting functions, and the other present in minor concentration for providing principally sulfur fixation and transfer functions. The particle present in major concentration, on the one hand, is constituted essentially of one or more Group VIII noble metals, preferably platinum, composited with a support comprised of a crystalline alumino silicate component distributed in an active cracking catalyst matrix, suitably one constituted of silica-alumina. The minor component particle, on the other hand, is comprised of one or more Group II-A metals, preferably magnesium, composited with a support, suitably silica-magnesia or silica-alumina, which may also contain a crystalline aluminosilicate zeolite component dispersed within thesilica-magnesia or silica-alumina support matrix.

Sulfur transfer cracking catalyst

An improved catalyst, and process utilizing said catalyst for catalytically cracking a sulfur-containing hydrocarbon feed, and for the fixation of sulfur by the catalyst and transfer thereof from the catalyst regeneration zone to the reaction zone of a catalytic cracking unit. The catalyst comprises an admixture of composite particles, one present in major concentration for providing principally cracking and combustion promoting functions, and the other present in minor concentration for providing principally sulfur fixation and transfer functions. The particle present in major concentration, on the one hand, is constituted essentially of one of more Group VIII noble metals, preferably platinum, composited with a support comprised of a crystalline alumino silicate component distributed in an active cracking catalyst matrix, suitably one constituted of silica-alumina. The minor component particle, on the other hand, is comprised of one or more Group II-A metals, preferably magnesium, composited with a support, suitably silica-magnesia or silica-alumina, which may also contain a crystalline aluminosilicate zeolite component dispersed within the silica-magnesia or silica-alumina support matrix.

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Slaughter, LA, United States of America

Terry A Reid