A kind of ultra-stable Y-type molecular sieve containing phosphorus and rare earth and preparation method thereof

Abstract

An ultra-stable Y-type molecular sieve containing phosphorus and rare earth and a preparation method thereof. The Y-type molecular sieve contains 4 to 11 wt% rare earth, 0.05 to 10 wt% phosphorus, 0.1 to 0.7 wt% sodium oxide, and has a pore volume of 0.33 to 0.39 mL / g, the volume of 2-100nm pores accounts for 15-30% of the total pore volume, the unit cell constant is 2.440-2.455nm, non-framework aluminum accounts for less than 20% of the total aluminum, the lattice collapse temperature is greater than 1050°C, and the B acid content The ratio to the amount of L acid is not less than 2.50. The preparation method includes: preparing a Y-type molecular sieve with a conventional unit cell size containing rare earth, roasting it for 4.5-7 hours in an atmosphere of 350-480°C and 30-90 volume % water vapor, phosphorus modification treatment and mixing with silicon tetrachloride gas. Contact reaction steps. The Y-type molecular sieve has good hydrothermal stability, high heavy oil cracking activity, good coke selectivity, and high yields of heavy oil converted into gasoline, liquefied gas and total liquid.

Description

technical field [0001] The invention relates to an ultra-stable Y-type molecular sieve containing phosphorus and rare earth and a preparation method thereof. Background technique [0002] At present, the industrial production of high-silicon Y-type zeolite mainly adopts the hydrothermal method. Rare earth-containing high-silicon Y-type zeolite can be prepared by performing multiple rare-earth ion exchanges and multiple high-temperature roasting on NaY zeolite. The disadvantages of zeolite are: because too harsh hydrothermal treatment conditions will destroy the structure of zeolite, Y-type zeolite with high silicon-alumina ratio cannot be obtained; although the production of aluminum outside the framework is very important for improving the stability of zeolite and forming new acid centers Beneficial, but too much aluminum outside the framework reduces the selectivity of zeolite; in addition, many dealuminated holes in zeolite cannot be filled by silicon migrated from the f...

AI Technical Summary

Problems solved by technology

Rare earth-containing high-silicon Y-type zeolite can be prepared by performing multiple rare-earth ion exchanges and multiple high-temperature roasting on NaY zeolite. The disadvantages of zeolite are: because too harsh hydrothermal treatment conditions will destroy the structure of zeolite, Y-type zeolite with high silicon-alumina ratio cannot be obtained; although the production of aluminum outside the framework is very important for improving the stability of zeolite and forming new acid centers Beneficial, but too much aluminum outside the framework reduces the selectivity of zeolite; in addition, many dealuminated holes in zeolite cannot be filled by silicon migrated from the framework in time, often resulting in lattice defects of zeolite, and the crystallization of zeolite remains Therefore, the thermal and hydrothermal stability of the rare earth-containing high-silicon Y-type zeolite prepared by the hydrothermal method is relatively poor, which is manifested in the low lattice collapse temperature, the crystallinity retention rate and the ratio of crystallinity after hydrothermal aging. low surface area retention

The cracking activity of the catalyst made of the zeolite as the active component is not high, and the conversion rate of heavy oil is low

[0012] However, the existing ultra-stable Y-type molecular sieves containing phosphorus and rare earths have low heavy oil cracking activity and poor coke selectivity.

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