Patent ID: 6858556

Claim:
A process for preparing a hydrocarbon conversion, stabilized dual zeolite catalyst, said catalyst comprising a stabilized high silica zeolite and a low silica molecular sieve, said process comprising the steps of: (a) loading high silica zeolite into a reactor and maintaining the zeolite at a temperature ranging between 100-125° C. for about 30 minutes; (b) heating the high silica zeolite to a temperature in the range of 450-500° C. for about 90 minutes in nitrogen atmosphere; (c) holding the zeolite at about 450-600° C. for about 90 minutes in an atmosphere of steam containing phosphate; (d) cooling the zeolite to obtain the stabilized high silica zeolite; (e) treating an alumina with a dilute acid and gelling it for about 10 minutes to obtain an alumina binder; (f) adding demineralized water to the alumina binder to make the alumina binder free flowing; (g) adding an acidified ammonium polysilicate to the alumina binder; (h) adding a milled clay slurry to the product of step (g); (i) adding a milled slurry of the low silica molecular sieve to the product of step (h); (j) adding demineralized water to the product of step (i) to obtain a silica-alumina-clay-low silica molecular sieve slurry; (k) adding the stabilized high silica zeolite as obtained in step (d) to the silica-alumina-clay-low silica molecular sieve slurry of step (j); and (l) spray-drying the product of step (k) and calcining the resulting product to obtain the stabilized dual zeolite catalyst.