摘要 |
A carbon monoxide combustion promoter is introduced to the circulating inventory of catalyst in a catalytic cracking unit as a mixture of particles rich in metal with particles free of metal, the net concentration of metal in the mixture being about 1 to 10 ppm. According to a preferred embodiment the particles rich in metal contain about 50 ppm of platinum, iridium, osmium, palladium, rhodium, ruthenium or rhenium. When such mixtures are supplied to the circulating inventory, the specific activity of the metal for carbon monoxide oxidation is enhanced, the activity of the mixture being higher than that of a catalyst in which the same quantity of metal is evenly distributed among all the particles. |