Addition of chlorine to regenerator

Abstract

A process for economically converting carbo-metallic oils to lighter products. The carbo-metallic oils contain 650.degree. F. and material which is characterized by a carbon residue on pyrolysis of at least about 1 and a Nickel Equivalents of heavy metals content of at least about 4 parts per million. This process comprises flowing the carbo-metallic oil together with particulate cracking catalyst through a progressive flow type reactor having an elongated reaction chamber, which is at least in part vertical or inclined, for a predetermined vapor riser residence time in the range of about 0.5 to about 10 seconds, at a temperature of about 900.degree. to about 1400.degree. F., and under a pressure of about 10 to about 50 pounds per square inch absolute sufficient for causing a conversion per pass in the range of about 50% to about 90% while producing coke in amounts in the range of about 6 to about 14% by weight based on fresh feed, and laying down coke on the catalyst in amounts in the range of about 0.3 to about 3% by weight. The spent, coke-laden catalyst from the stream of hydrocarbons formed by vaporized feed and resultant cracking products is separated and regenerated in one or more regeneration beds in one or more regeneration zones by burning the coke on the spent catalyst with oxygen in the presence of chlorine. The bed density is in the range of about 25 to about 50 pounds per cubic foot and the bed or beds are sustained by fluidization gas containing combustion-supporting gas having a linear velocity in the range of about 0.2 to about 4 feed per second. The chlorine reduces the CO.sub.2 /CO ratio, thereby reducing the heat output of the regenerator. The catalyst particles are retained in the regeneration zone or zones in contact with the combustion-supporting gas for an average total residence time in said zone or zones of about 5 to about 30 minutes to reduce the level of carbon on the catalyst to about 0.25% by weight or less. The regenerated catalyst is recycled to the reactor and contacted with fresh carbo-metallic oil.