Method for synthesizing fine grain NaY molecular sieve

Abstract

The invention relates to a method for synthesizing a NaY molecular sieve, which comprises the steps of synthesizing director reagents, synthesizing gel and crystallizing. The method is characterized in that the mol composition of the director reagent is (10-30)Na2O:Al2O3:(0.1-8) SiO2:(150-380)H2O. The method can synthesize the small crystal grain NaY molecular sieve with the grain diameter of between 150 and 350nm.

Description

technical field [0001] The invention relates to a method for synthesizing NaY molecular sieves. Background technique [0002] Y-type molecular sieves commonly used in catalytic cracking catalysts are usually prepared by modifying NaY molecular sieves by various methods. At present, most of the methods for industrially producing NaY molecular sieves adopt the directing agent method proposed by Grace Company of the United States in US3639099 and US3671191. The method is first to prepare the molar composition as (15-17)Na 2 O: Al 2 o 3 :(14-16)SiO2 2 :(285-357)H 2 The directing agent of O, the crystal nucleus particle size of the directing agent is usually less than 0.05 microns, and then the directing agent is mixed with water glass, sodium metaaluminate, aluminum sulfate and other raw materials according to the molar ratio (3-6)Na 2 O: Al 2 o 3 :(8-12)SiO2 2 :(120-200)H 2 The ratio of O was mixed to prepare a crystallization reaction mixture, and then the mixture wa...

AI Technical Summary

Problems solved by technology

Due to the limitation of internal diffusion, in many cases, it is difficult for the macromolecules in hydrocarbon oil to penetrate into the pores of large-grained molecular sieves, so the maximum accessibility of the active center is relatively poor, while small-grained molecular sieves have larger external areas and more The active center on the outer surface, and the diffusion path in the hole is short, and the utilization rate of the active site on the inner surface is improved