Method for modifying molecular sieve

Abstract

The invention discloses a method for modifying a molecular sieve. The method comprises the following steps: dissolving a compound containing III B metal ions in the periodic table of the elements in water or acid to form a solution, mixing the solution with an organic complexing agent and / or a dispersing agent and a precipitating agent, stirring for at least 10 minutes to form a precipitate containing III B elements; mixing the obtained precipitate and molecular sieve slurry at the temperature of 5-100 DEG C, and stirring for at least 10 minutes to obtain mixed slurry of the precipitate containing the III B elements and the molecular sieve, and performing spray drying, calcining or not calcining, so as to obtain the modified molecular sieve, wherein a weight ratio, based on oxides, of the III B group elements to a dry basis of the molecular sieve is (0.3-10):100; a molar ratio of the organic complexing agent to the III B group metal ions is (0.3-10):1; a molar ratio of the dispersing agent to the metal ions is (0.2-16):1. The molecular sieve prepared by the method disclosed by the invention has excellent activity and stability and high heavy metal pollution resistance.

Description

technical field [0001] The invention relates to a method for modifying catalytic materials, in particular to a method for modifying molecular sieves. Background technique [0002] Crude oil is increasingly heavy and inferior. Efficient processing of heavy oil and blending of residual oil has become an urgent need for refiners to improve processing capacity and obtain higher profits. Catalytic cracking is the most important process of heavy oil processing. Due to its significant advantages such as high conversion efficiency of heavy oil, good product quality, non-hydrogenation and low operating pressure, it occupies a pivotal position in the process of processing heavy oil in refineries. It is the refinery's profit main source of . According to statistics, there are currently about 420 sets of catalytic cracking units in the world. The largest single set of catalytic cracking units has reached 10 million tons per year, with a total processing capacity of about 737 million to...

AI Technical Summary

Problems solved by technology

It has been found that rare earth ions exchange with cations such as sodium in molecular sieves, migrate into molecular sieves, and play a role in improving the activity and stability of molecular sieves. However, once the ion-exchanged rare earths come into contact with vanadium, they are easy to break away from the framework structure of molecular sieves and form vanadium Acidic rare earths, on the contrary, make the structural stability of molecular sieves worse; and rare earths that exist in the form of independent phases can be used to trap heavy metals in the process of catalytic cracking reaction due to their different positions and states, and play the role of anti-heavy metals

Therefore, the above-mentioned rare earth molecular sieve prepared by rare earth ion exchange does not contain rare earth in independent phase, so its ability to resist heavy metal pollution is insufficient

[0010] The rare earth-containing Y-type molecular sieve prepared by the precipitation method, even if a rare earth precipitate is formed and contains a separate phase of rare earth, the particles of the rare earth precipitate are large, which is not conducive to uniform dispersion on the surface of the molecular sieve, and is not conducive to effective contact with heavy metals. , Capture heavy metals in time

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