A kind of catalytic cracking catalyst and its preparation and application

Abstract

A catalytic cracking catalyst and its preparation and application. The catalyst contains modified Y-type molecular sieve, alumina binder and clay; the magnesium oxide content of the modified Y-type molecular sieve is 0.5% by weight to 4.5% by weight. The sodium content is 0.1% to 0.5% by weight, the total pore volume is 0.33mL / g to 0.39mL / g, and the pore volume of the secondary pores with a pore diameter of 2nm to 100nm of the modified Y-type molecular sieve accounts for the percentage of the total pore volume. is 10% to 25%, the unit cell constant is 2.440nm to 2.455nm, the non-framework aluminum content in the modified Y-type molecular sieve accounts for no more than 20% of the total aluminum content, and the lattice collapse temperature is no less than 1040°C. Moreover, the ratio of the B acid amount to the L acid amount in the total acid amount of the modified Y-type molecular sieve measured at 200°C using the pyridine adsorption infrared method is not less than 2.30; when the molecular sieve is subjected to ultraviolet-visible light analysis, the ultraviolet-visible absorption spectrum There is no absorption at 285nm~295nm. The catalytic cracking catalyst is used for catalytic cracking of heavy oil, has lower coke selectivity, higher gasoline yield, liquefied gas yield, and higher isomeric hydrocarbon content in the gasoline.

Description

technical field [0001] The invention relates to a catalyst for catalytic cracking of heavy oil, its preparation method and application. 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. Zeolite has the following disadvantages: the structure of zeolite can be destroyed due to too harsh hydrothermal treatment conditions, and Y-type zeolite with a high silicon-aluminum ratio cannot be obtained; although the production of aluminum outside the framework is beneficial to improving the stability of zeolite and forming new acid centers, However, 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...

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. Zeolite has the following disadvantages: the structure of zeolite can be destroyed due to too harsh hydrothermal treatment conditions, and Y-type zeolite with a high silicon-aluminum ratio cannot be obtained; although the production of aluminum outside the framework is beneficial to improving the stability of zeolite and forming new acid centers, However, 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, which often causes lattice defects of zeolite, and the crystallization retention of zeolite is relatively low. Low

However, the Y molecular sieve prepared by this method has poor thermal and hydrothermal stability, unsatisfactory reactivity and selectivity, and can only increase the content of isobutane under certain conditions, but cannot effectively increase the content of isomeric hydrocarbons in gasoline

[0007] The performance of the ultra-stable molecular sieves prepared by the hydrothermal method or the gas phase method in the prior art cannot well meet the current needs of processing heavy oil and inferior oil and improving the quality of gasoline

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