Modified molecular sieve capable of improving coking performance

Abstract

The invention relates to a modified molecular sieve capable of improving coking performance. The modified molecular sieve is prepared from a NaY type molecular sieve by the twice-crosslinking twice-roasting preparation method. According to the weight ratio, in the modified molecular sieve, the content of RE2O3 is 0.05 to 4 percent, the content of P is 0.05 to 5.0 percent; and the crystal cell of the modified molecular sieve is 2.430 to 2.440nm, and the crystallinity is between 35 and 55 percent. The modified molecular sieve has bigger hole volume of medium-and-large-sized holes and good stability; under the same condition of preparation process for catalyst, compared with the comparison molecular sieve, the modified molecular sieve has the advantages of reducing coke yield of the catalyst, simultaneously further improving the heavy oil cracking capability, further improving total liquid yield, and particularly facilitating the improvement of the yield of light oil.

Description

technical field [0001] The invention relates to a modified molecular sieve capable of improving coking performance, in particular to a modified molecular sieve used in a low-coking FCC catalyst. Background technique [0002] In the process of petroleum refining and petrochemical production, the deactivation of catalyst caused by carbon deposition is an important technical and economical problem. Any increase in coke production will lead to a decrease in unit processing capacity and conversion rate. The formation of coke is the result of many factors, mainly related to the properties of raw oil, catalyst activity, atomization effect, and reaction conditions. Among them, as far as the catalyst is concerned, since most of the catalytic reactions are mainly carried out on the active components of the catalyst, reducing the coke on the active components can reduce the reaction coke. [0003] In the FCC reaction process, there are mainly the following reactions on the active comp...

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Problems solved by technology

From the perspective of modification methods, P-treated molecular sieves mainly include two types. One is to modify the treated active components with P. This type of modification method mainly adjusts the performance and does not fully exert the effect of P on molecular sieves. protection function; the other is to directly introduce P into the modification process of molecular sieves. Most of these methods use rare earth modification or simultaneous modification of rare earth and phosphorus before roasting. Previously, there were rare earth supports on the molecular sieve, so the shrinkage of the molecular sieve unit cell was limited; there are also patents such as CN1110532C, which proposed a method of modifying NaY molecular sieves with phosphorus-containing substances first, and then roasting, but because they only used one ultra-stable roasting Or dry roasting treatment method, so the stability of the modified molecular sieve is limited

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