Process for the production of LPG rich in olefins and high quality gasoline

A process for producing LPG rich in propylene, butylenes and high octane number gasoline by catalytic conversion which comprises:

• (1) contacting in a riser or a fluidized bed reactor a preheated hydrocarbon feedstock with a solid acidic catalyst which contains a matrix and three zeolithic active components including rare-earth-containing high silica zeolite having the structure of a pentasil (ZRP), rare-earth-Y zeolite (REY) and high silica Y zeolite, and
• (2) converting said feedstock in the reactor at a temperature in the range of from about 480.degree. C. to about 550.degree. C., a pressure in the ranger of from about 130 KPa to about 350 KPa, a weight hourly space velocity in the range of 1 to 150 hr-1, a catalyst-to-oil ratio in the range of 4 to 15, and a steam-to-feedstock ratio between 0.05-0.12:1 by weight;
• wherein said catalyst is characterized as follows:
• (1) the anhydrous state formula of said ZRP zeolite is 0.01-0.30 RE.sub.2 O.sub.3 . 0.1-1.0 Na.sub.2 O . Al.sub.2 O.sub.3 . 20-60 SiO.sub.2 ;
• (2) said ZRP zeolite is in hydrogen-exchanged form;
• (3) 5-19% of said REY zeolite is in the form of RE.sub.2 O.sub.3, and the crystallite size of said REY zeolite is 0.5-10 microns.
• (4) the Na.sub.2 O content of said high silica Y zeolite does not exceed 4 wt%, and the crystallite size of said high silica Y zeolite is 0.5-10 microns;
• and
• (5) said matrix is an amorphous silica/alumina or silica/magnesia gel containing not more than 70 wt% SiO.sub.2.