IMPROVED PROCESS FOR THE PREPARATION OF A FCC ADDITIVE WHICH INCREASES OCTANE IN PETROL, AND RESULTING ADDITIVE

The present invention is related to an improved process for the preparation of a FCC additive which increases octane in petrol, and when added in controlled portions to the main stock of the catalyst used in the process of fluid bed catalytic disintegration, i.e., when used as additive, allows the amount of octane to be increased in petrol, as well as the yield of specific compounds integrating so called LP Gas, especially that of C3 to C5 olefins (propylene, isobutylene, and isoamylene) which are simultaneously produced in the same process. The catalyst of the present invention is prepared from a natural clay of the kaolinite, montomorionite or sepiolite type, a silica source such as silica gel or colloidal silica, an aluminum source such as bayerite, gibbsite, bohemite or colloidal alumina, a synthetic zeolite of between ZSM-5, ZSM-11, ZSM-35, characterized in that they comprise a composition in terms of silica-alumina molar ratio higher than 12, and restriction indexes between 1 and 12, but preferably of pentasyl ZSM-5 type, characterized in that it comprises a silica to alumina composition ratio of between 14-2000, and crystal sizes of between 0.01-5 ??m, a phosphorous source as phosphorous pentoxide, and a lanthanum source such as lanthanum nitrate pentahydrated or lanthanum trichloride, which is integrated in microspheroidal particles of 20-200 microns in size, preferably 40-100 microns containing between 1-25 percent by weight of zeolite, preferably 5-15 percent by weight , and lanthanum oxide in an amount of 1-5 percent by weight. La presente invencion se relaciona con un procedimiento mejorado de preparacion de un aditivo FCC incrementador de octano en gasolina que se emplea como catalizador de desintegracion que adicionado en porciones controladas al inventario principal del catalizador utilizado en el proceso de desintegracion catalítica en lecho fluido, es decir empleado como aditivo, permite elevar el numero de octano de la gasolina así como el rendimiento de ciertos compuestos que integran el llamado Gas LP, especialmente el de las olefinas C3 a C5, (propileno, isobutileno e isoamileno) producidas paralelamente en el mismo proceso. El catalizador objeto de la presente invencion es preparado a partir de una arcilla natural del tipo de la caolinita, montomorionita o sepiolita, una fuente de sílice como sílice gel o sílice coloidal, una fuente de aluminio como bayerita, gibbsita, boehmita o alumina coloidal, una zeolita sintética de entre ZSM-5,