A catalytic cracking catalyst

Abstract

The invention provides a catalytic cracking catalyst. The catalytic cracking catalyst contains clay, an alumina binder and a modified Y type molecular sieve. The modified Y type molecular sieve comprises 5 to 12 wt% of rare earth and no more than 0.5 wt% of sodium oxide, and has a total pore volume of 0.36 to 0.48 mL / g; the pore volume of secondary pores accounts for 20 to 38% of the total pore volume; a lattice constant is 2.440 nm to 2.455 nm; the content of non-framework aluminum is no more than 10% of total aluminum content; lattice collapse temperature is higher than 1060 DEG C; and a ratio of the amount of acid B to the amount of acid L is no less than 3.50. A preparation method for the catalytic cracking catalyst comprises the following steps: preparing a rare earth-containing Y type molecular sieve with a conventional cell size; carrying out roasting in a water vapor atmosphere with a temperature of 350 to 520 DEG C and a volume percentage of 30 to 95% for 4.5 to 7 h; carryingout a contact reaction with silicon tetrachloride; and carrying out acid treatment. The catalyst has higher heavy oil conversion activity, low coke selectivity, and higher gasoline yield, liquefied gas yield, light oil yield and total liquid yield.

Description

technical field [0001] The invention relates to a catalytic cracking catalyst. Background technique [0002] Y-type molecular sieves have been the main active component of catalytic cracking (FCC) catalysts since they were first used in the 1960s. However, with the intensification of heavy crude oil, the content of polycyclic compounds in FCC raw materials increased significantly, but their diffusion capacity in zeolite channels decreased significantly. The pore size of Y-type molecular sieve as the main active component is only 0.74nm, and it is directly used to process heavy fractions such as residual oil. The accessibility of the active center of the catalyst will become the main obstacle to the cracking of polycyclic compounds contained therein. [0003] Molecular sieve pore structure is closely related to cracking reaction performance, especially for residual oil cracking catalysts, the secondary pores of molecular sieve can increase the accessibility of residual oil m...

AI Technical Summary

Problems solved by technology

The ultra-stable molecular sieve prepared by this method has a high silicon-alumina ratio, a small unit cell constant, and contains a certain amount of rare earth, but it does not involve the preparation of a molecular sieve with secondary pores. The high-stable molecular sieve has poor accessibility to the active center , the activity is not high

[0014] The inventors of the present invention found that the catalytic cracking catalyst containing the ultra-stable Y-type molecular sieve prepared by the prior art is difficult to simultaneously have higher heavy oil catalytic cracking activity and better coke selectivity

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