Combined modification method for mesopore USY molecular sieve

Abstract

The invention relates to a modification method for a USY molecular sieve and in particular relates to a combined modification method for a mesopore USY molecular sieve. The combined modification method for the mesopore USY molecular sieve comprises that raw materials such as a USY material, an organic acid solution and an inorganic salt solution are measured in ratio, stirring in a closed reactor is carried out, temperature is increased to 90 DEG C, an organic acid-inorganic salt combined dealumination reaction is carried out for 8 hours; reactants are washed at room temperature, and suction filtration is carried out until the surface of USY is neutral; and drying is carried out at constant temperature of 110 DEG C for 16 hours, so that the USY molecular sieve product is obtained. The combined modification method for the mesopore USY molecular sieve has the advantages that a mixed aqueous solution of organic acid and inorganic salt is adopted for treating the USY type molecular sieve, so that high crystallinity of the molecular sieve can be maintained, silica-alumina ratio of the molecular sieve is increased, lattice constant is reduced, specific surface of the molecular sieve is increased, and acidity and acid distribution of the molecular sieve are improved; and more secondary holes are formed through dealumination, so that components with larger molecular diameter can easily enter into pore passages of the molecular sieve or get close to the surface of the molecular sieve, and conversion efficiency of hydrogen cracking can be improved.

Description

technical field [0001] The invention relates to a method for modifying USY molecular sieves, in particular to a combined modification method for mesoporous-rich USY molecular sieves. technical background [0002] Modified USY requires a certain amount of secondary pores. After increasing the concentration of the modifier, the molecular sieve will be dealuminated in a large amount, which will create a large number of secondary pores, but the crystallinity will drop sharply, and the thermal and hydrothermal stability will deteriorate. . At present, the commonly used methods of USY modification are: [0003] Hydrothermal dealumination treatment, the USY obtained by this treatment contains more non-skeleton aluminum, low crystallinity, and poor content of secondary pores, which cannot meet the performance requirements of the catalyst carrier for high and medium oil type hydrocracking. [0004] Chemical treatment methods include SiCl4 high temperature gas phase method, (NH 4 )...

AI Technical Summary

Problems solved by technology

However, the modification conditions of these methods are relatively harsh, and some chemicals are expensive, which is not conducive to the realization of industrialization

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