Modified Y-type zeolites having a trimodal intracrystalline structure, method for making same, and use thereof
The invention relates to a Y-type zeolite having a modified faujasite structure, the intracrystalline structure of which includes at least one network of micropores, at least one network of small mesopores having an average diameter ranging from 2 to 5 nm, and at least one network of large mesopores having an average diameter ranging from 10 to 50 nm. The invention also relates to particles including such zeolites and to the use thereof in a method for processing crude oil, particularly as a hydrocracking catalyst.
1. A modified zeolite Y having a modified faujasite structure, whose intracrystalline structure has at least one network of micropores, at least one network of small mesopores with a mean diameter of 2 to 5 nm, and at least one network of large mesopores with a mean diameter of 10 to 50 nm, these various networks being interconnected, wherein the ratio Vs/Vl of the volume of the small mesopores (Vs) to the volume of the large mesopores (Vl) of the modified zeolite Y is greater than or equal to 1, and the Si/Al atomic ratio of the modified zeolite Y is from 17 to 35; and
wherein the modified zeolite Y is produced by a process comprising
(i) suspending a zeolite Y or a composite material comprising the zeolite Y in a basic aqueous solution comprising at least one strong base at a concentration ranging from 0.001 to 0.5 M, at room temperature, with magnetic or mechanical stirring,
b) filtering off the product obtained in step (a) and washing with a solvent,
c) optionally drying the product obtained in step (b),
d) placing the product obtained in step (c) in contact, with stirring, in a solution of NH 4 NO 3 ,
e) washing the product obtained in step (d) with distilled water to neutral pH,
f) calcining the product obtained in step (e), and
g) recovering the product obtained in step (f), which is the modified zeolite Y.
2. The modified zeolite as claimed in claim 1 , characterized in that it has a total mesopore volume of greater than or equal to 0.20 ml/g.
3. The modified zeolite as claimed in claim 1 , characterized in that it has a micropore volume of less than or equal to 0.20 ml/g.
4. The modified zeolite as claimed in claim 1 , characterized in that it has a total mesopore volume/micropore volume ratio of greater than or equal to 1.
5. Catalytic particles, comprising the modified zeolite as claimed in claim 1 and at least one binder.
6. The particles as claimed in claim 5 , comprising at least 20% by weight of zeolites relative to the total weight of the particles.
7. The particles as claimed in claim 5 , also comprising a catalytic metal.
8. The particles as claimed in claim 5 , wherein the at least one binder comprises silica or alumina.
9. The modified zeolite as claimed in claim 1 , characterized in that the modified zeolite Y is produced by a process further comprising a step of neutralization of the solution before the first filtration.