Catalytic cracking catalyst

Abstract

The invention provides a catalytic cracking catalyst. The catalytic cracking catalyst contains a modified Y type molecular sieve containing magnesium, alumina containing an additive and clay. In the modified Y type molecular sieve containing magnesium, the content of rare earth oxide is 4 to 10 wt%; the content of magnesium oxide is 0.1 to 4 wt%; the content of sodium oxide is 0.3 to 0.8 wt%; a total pore volume is 0.33 to 0.39 mL / g; the pore volume of secondary pores with pore diameters of 2 to 100 nm in the modified Y type molecular sieve accounts for 10 to 30% of the total pore volume; a lattice constant is 2.440 nm to 2.455 nm; the content of non-framework aluminum in the modified Y type molecular sieve is no more than 20% of total aluminum content; and lattice collapse temperature isno less than 1045 DEG C. The modified Y type molecular sieve has higher heavy oil conversion activity, low coke selectivity, and higher diesel oil yield, light oil yield and total liquid yield.

Description

technical field [0001] The invention relates to a magnesium-containing highly stable modified Y-type molecular sieve and a preparation method thereof. Background technique [0002] The catalytic cracking catalyst containing magnesium-containing high-silicon Y-type zeolite is used for the conversion of heavy oil to increase the production of diesel oil. At present, the industrial production of high-silicon Y-type zeolite mainly adopts the hydrothermal method: NaY zeolite is subjected to multiple rare earth ion exchange and high-temperature hydrothermal roasting for multiple times, and high-silicon Y-type zeolite containing rare earths can be prepared, which is also the preparation of high-silicon Y-type zeolite. Silica Y-type zeolite is the most conventional method, but the disadvantage of preparing rare earth high-silicon Y-type zeolite by hydrothermal method is that the structure of zeolite will be destroyed due to too harsh hydrothermal treatment conditions, and Y-type zeo...

AI Technical Summary

Problems solved by technology

At present, the industrial production of high-silicon Y-type zeolite mainly adopts the hydrothermal method: NaY zeolite is subjected to multiple rare earth ion exchange and high-temperature hydrothermal roasting for multiple times, and high-silicon Y-type zeolite containing rare earths can be prepared, which is also the preparation of high-silicon Y-type zeolite. Silica Y-type zeolite is the most conventional method, but the disadvantage of preparing rare earth high-silicon Y-type zeolite by hydrothermal method is that the structure of zeolite will be destroyed due to too harsh hydrothermal treatment conditions, and Y-type zeolite with high silicon-aluminum ratio cannot be obtained ; Although the generation of extra-framework aluminum is beneficial to the stability of the zeolite and the formation of new acid centers, too much extra-framework aluminum reduces the selectivity of the zeolite; in addition, many dealuminated holes in the zeolite cannot be removed by the framework in time. Migrated silicon often causes lattice defects of zeolite, and the crystallization retention of zeolite is low; therefore, the thermal and hydrothermal stability of rare earth-containing high-silicon Y-type zeolite prepared by hydrothermal method is poor, which is manifested in Its lattice collapse temperature is low, and its crystallinity retention rate and specific surface area retention rate are low after hydrothermal aging

However, the prior art does not propose how to further improve the heavy oil cracking activity of gas-phase ultrastable molecular sieves.

[0005] The existing magnesium-containing high-silicon Y zeolite cracking catalyst has low heavy oil cracking activity and low diesel selectivity

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