PROCESS FOR THE PREPARATION OF CATALYSTS BASED ON ZEOLITES TREATED WITH PHOSPHORIC ACID, USEFUL FOR CATALYTIC CRACKING UNITS

摘要

The invention relates to a process for preparing a catalyst which contains a zeolite, and which improves the activity and selectivity in distilled media, reducing the production of dry gas and coke. The catalyst is prepared by modifying the zeolite with an aqua solution of phosphoric acid. A prefered zeolite is a zeolite USY which has been partially dealuminized by a prior calcination-vapor treatment, and wherein the treatment with H3PO4 is carried out in an aqueous solution containing between 0.5 and 4 % by weight of H3PO4 with respect to the zeolite. The modified zeolite is combined with the precursor of the matrix and is atomized to give the zeolite the appropriate shape and size in order to use it in FCC units. The catalyst is useful for the cracking of gas oil, and heavier supplies.