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Small crystal grain Y-shaped molecular sieve and preparation method thereof

A technology of small crystal grains and molecular sieves, applied in the direction of crystalline aluminosilicate zeolite, octahedral crystalline aluminosilicate zeolite, etc. Poor thermal stability and other problems, to achieve the effect of ensuring the continuity of the skeleton, good stability, and high crystallization retention

Active Publication Date: 2010-06-09
CHINA PETROLEUM & CHEM CORP +1
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Problems solved by technology

CN1382632A discloses a super-stabilizing method of small-grain Y-type zeolite, which is obtained by contacting the dry gas of silicon tetrachloride with small-grain NaY zeolite and washing it. Stability is just relatively poor, and this inventive method adopts the mode of vapor phase dealumination of silicon to process molecular sieve simultaneously, and this makes the thermal and hydrothermal stability of product worse, and activity is low; Small, high energy consumption and other disadvantages
Especially when the small-grain NaY zeolite (such as adopting the NaY zeolite synthesized by CN1081425A in the embodiment) with poor thermal stability and hydrothermal stability is modified, its crystallization retention is below 95%, due to the poor performance of raw materials , the stability of the silicon-aluminum framework structure in the molecular sieve is poor, and it is easy to cause the removal of the framework aluminum during the modification process, and at the same time, a part of the framework silicon is also removed, which is easy to cause part of the framework to collapse, making the product The crystallization retention is low, and the activity of molecular sieves is not high
The modification method of comparative example 3 is to exchange ammonium with ammonium sulfate first, and then add ammonium fluorosilicate, and the obtained small grain BM-3 has a lower degree of crystallization retention, which is only 70%. In comparative example 3, the raw material It is prepared by the method of non-directing agent, so the skeleton silicon-alumina of its raw material is relatively low. In the process of post-processing, it is easy to cause large-scale collapse of the skeleton silicon-alumina, resulting in poor activity of the product and lower crystallization retention.

Method used

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  • Small crystal grain Y-shaped molecular sieve and preparation method thereof
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  • Small crystal grain Y-shaped molecular sieve and preparation method thereof

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preparation example Construction

[0029] The preparation method of small grain NaY type molecular sieve of the present invention specifically comprises the following steps:

[0030] A. Preparation of directing agent at low temperature.

[0031] According to Na 2 O:Al 2 o 3 : SiO 2 :H 2 O=10~20: 1: 10~20: 300~400 feed molar ratio, at a temperature above 0°C and less than 15°C, preferably at a temperature of 0°C to 10°C, the water glass is slowly stirred under the condition of stirring Add it into the high-alkaline sodium metaaluminate solution and mix evenly, then stir at the above temperature at a constant temperature and speed for 0.5-2 hours; then seal the mixed solution in a synthesis kettle, and age it at a static temperature for 10-14 hours to obtain a directing agent The directing agent is preferably added with 20% to 40% of the weight of the directing agent before use.

[0032] B. Preparation of gel at low temperature.

[0033] Mix water glass, aluminum sulfate solution, low-alkali sodium metaalu...

Embodiment 1

[0044] This example is to prepare NaY molecular sieve with small crystal grains as raw material.

[0045] The raw materials used are as follows:

[0046] High alkali sodium metaaluminate: Na 2 O content 291g / L, Al 2 o 3 Content 42g / L; low alkali sodium metaaluminate: Na 2 O content 117g / L, Al 2 o 3 Content 77g / L; water glass: SiO 2 Content 250g / L, modulus 3.2; aluminum sulfate: Al 2 o 3 Content 90g / L.

[0047] Preparation of LY-1:

[0048] A. Preparation of directing agent: Slowly add 1200ml of water glass into 800ml of high alkali sodium metaaluminate under stirring condition at 10°C. After adding water glass, stir at constant temperature for 40 minutes. Stirring was stopped, and the mixed solution was sealed in a container, and aged at a temperature of 5°C for 12 hours at a constant temperature. After the constant temperature is finished, add 667ml of clean water to the mixed solution as a guiding agent.

[0049] B. Preparation of the gel: Add 59.4ml of aluminum ...

Embodiment 2

[0056] Firstly, ammonium exchange is carried out on the raw material small-grain NaY molecular sieve LY-1. The preparation concentration is 10 liters of 0.5mol / l ammonium nitrate aqueous solution. Weigh 1,000 grams of small-grain NaY molecular sieve, dissolve it in 10 liters of prepared ammonium nitrate aqueous solution, stir at 90°C for 1 hour at a constant temperature of 300 rpm, then filter the molecular sieve, and leave a small sample for analysis of NaY 2 O content; repeat the above operation until Na in the molecular sieve 2 The O content reached 2.5-5wt%, and the sample number obtained after drying was LNY-1, and its properties were listed in Table 1.

[0057] Measure 1 liter of clean water and dissolve 200 grams of LNY-1 in the clean water, heat up and stir rapidly, the temperature is 95°C, and the stirring speed is 300rpm. Within 2 hours, add ammonium hexafluorosilicate aqueous solution to the molecular sieve slurry at a uniform speed, add a total of 50 grams of amm...

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Abstract

The invention discloses a small crystal grain Y-shaped molecular sieve and a preparation method thereof. The small crystal grain Y-shaped molecular sieve has the following properties that: the molar ratio of SiO2 / Al2O3 is 5.0-20.0; the average diameter of crystal grains is 100 to 700nm; the crystallization reservation degree is over 95 percent; and the weight percentage of sodium oxide is less than or equal to 0.1 percent. The small crystal grain Y-shaped molecular sieve takes a small crystal grain NaY molecular sieve with good thermal stability and hydrothermal stability as a raw material, has a high silicon-aluminum ratio, good stability and a uniform framework, namely a silicon-aluminum structure, can uniformly remove aluminum and supplement silica in an ammonium exchanging and ammonium fluosilicate dealuminizing and silica-supplementing process, guarantees the framework continuity of the molecular sieve product, decreases the probability of framework structure collapse, and furthest reserves the integrity of the product, namely the silicon-aluminum-oxygen structure so that the product has very high crystallization reservation degree.

Description

technical field [0001] The invention relates to a Y-type molecular sieve and a preparation method thereof, in particular to a preparation method of a small-grain Y-type molecular sieve. Background technique [0002] At present, molecular sieves that can be used as cracking active components in the field of heavy oil cracking include Y-type, β-type and ZSM, among which Y-type molecular sieves are most commonly used. At present, the methods for industrially producing Y-type molecular sieves basically adopt the directing agent method proposed by GRACE Company of the United States in USP 3639099 and USP 4166099. The crystal grains of the obtained common Y-type molecular sieves are generally about 1000nm, and the crystal grains are relatively large. The pores are relatively long, and the diffusion resistance is high. It is difficult for macromolecules to enter the pores for reaction, and it is also difficult for the products after the reaction to diffuse out. Therefore, the crack...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B39/24
Inventor 王凤来刘昶关明华杜艳泽
Owner CHINA PETROLEUM & CHEM CORP
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