| 摘要 |
A cracking catalyst having good resistance to metal poisoning has at least two particle fractions of different particle sizes, the cracking catalyzing zeolite material being concentrated to the coarser particle size fractions, and the finer particle size fractions being formed from material having relatively lower or no or insignificant cracking catalyzing activity. The particles of the finer particle size fractions have a matrix of kaolin and amorphous alumina-silica and may contain for example, an SOx eliminating additive such as Al2O3, CaO and/or MgO. The coarser particle size fractions having cracking catalyzing effect have a mean particle size of from 80 to 125 mu m and the finer particle size fractions a mean particle size of from 30 to 75 mu m. The coarser particle size fractions have a zeolite content of at least 20 weight % and may have a zeolite content of up to 100 weight %, the remainder consisting essentially of material which has relatively lower or no or insignificant cracking-catalyzing activity and which consists of kaolin and amorphous alumina-silica. The catalyst mass as a whole may have a zeolite content of up to 50 weight %. |
