Catalytic cracking catalyst and preparation method thereof

Abstract

The invention relates to a catalytic cracking catalyst and a preparation method thereof. The catalyst contains a first Y-type molecular sieve, a second Y-type molecular sieve and a third Y-type molecular sieve, wherein the rare-earth content in the first Y-type molecular sieve is 10-25 wt%, the cell constant is 2.440-2.472nm, the crystallinity is 35-65%, the silicon / aluminum atomic ratio in the framework is 2.5-5.0, and the product of the ratio of 2theta=11.8+ / -0.1 degree peak intensity to 2theta=12.3+ / -0.1 degree peak intensity in an X-ray diffraction pattern and the rare-earth weight percent in the molecular sieve is greater than 50; the second Y-type molecular sieve is a magniferous overstable Y-type molecular sieve; and the third Y-type molecular sieve is a rare-earth-containing DASY molecular sieve. The preparation method comprises the following steps: preparing a mixed slurry containing the molecular sieves, an adhesive and clay, carrying out spray drying, washing and drying. The catalyst has higher conversion rate and diesel yield.

Description

Background technique [0001] Catalytic cracking (FCC) is an important secondary processing process of crude oil and occupies a pivotal position in the oil refining industry. In the catalytic cracking process, heavy fractions such as vacuum distillate oil or residues of heavier components react in the presence of catalysts and are converted into high value-added products such as liquefied gas, gasoline, and diesel oil. In this process, it is usually necessary to use Catalytic material with high cracking activity. Microporous zeolite catalytic materials are widely used in petroleum refining and processing industries due to their excellent shape-selective catalytic performance and high cracking reactivity. Among them, Y-type molecular sieve has been the main active component of catalytic cracking catalyst since it was first used in the 1960s. Especially the Y-type molecular sieve modified by rare earth has a significant effect on improving the acidity and structural stability of...

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Problems solved by technology

[0011] In the prior art, regardless of the rare earth Y molecular sieve obtained by the double-cross-two-baking process or the one-cross-one-baking process, the rare earth content in the product is always lower than the total rare earth amount input, such as CN1053808A, CN1069553C, several disclosed in CN1026225C All kinds of rare earth Y molecular sieves have this feature. Even if more rare earth ions are located in the small cages, it is inevitable that some rare earth ions still exist in the supercages, and the rare earth ions in the supercages will be washed in the subsequent washing process. It is backwashed down, resulting in the loss of rare earths, resulting in a decrease in the utilization rate of rare earths

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