Improved cracking catalyst and method of manufacture.

摘要

Cracking catalysts having improved activity and having selectivity to the gasoline fraction (C5/430 DEG F) are prepared by: (a) forming an aqueous slurry containing, on a dry solids weight percent basis: 1) 5 to 40 weight percent of a sodium zeolite Y characterized by a Na2O content of greater than 2 percent by weight and characterized by a unit cell parameter (a0) greater than 24.50 and less than 24.66; 2) 5 to 40 percent by weight of an alumina; and 3) 40-90 percent by weight of at least one porous oxide matrix; (b) spray drying; (c) ammonium exchanging the spray dried product of step (b) to provide a product, on a dry basis, containing less than 1.2 weight percent Na2O; (d) calcining the product of step (c) at an effective temperature to provide a product characterized by a zeolite component characterized by a unit cell parameter less than 24.66 and greater than 24.55; and (e) ammonium exchanging the product of step (d) under effective conditions to provide a product containing less than 0.8 weight percent Na2O, based on the weight of the solid catalyst.