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A kind of method for preparing compound molecular sieve

A composite molecular sieve and molecular sieve technology, applied in molecular sieves and base exchange compounds, chemical instruments and methods, crystalline aluminosilicate zeolites, etc., can solve the problem of synergistic catalysis of Y and ZSM-5 molecular sieves, which cannot be realized The close contact and uniform dispersion of molecular sieves, the degree of in-situ growth of the second phase molecular sieves cannot be guaranteed, etc., to achieve good industrial application prospects, broad industrial application prospects, and fast diffusion effects

Inactive Publication Date: 2020-11-27
CHINA UNIV OF PETROLEUM (EAST CHINA)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, due to the limitations of the synthesis system, the degree of in-situ growth of the second phase molecular sieve cannot be guaranteed, and the silicon-aluminum ratio (Si / Al) of the obtained Y molecular sieve framework will not exceed 3, and the formed Y and ZSM-5 are generally large grains and non-mesoporous micron molecular sieves
Moreover, even if a composite molecular sieve with a better degree of in situ crystallization and a smaller molecular sieve grain size is obtained, subsequent steps such as ion exchange, hydrothermal treatment, and introduction of mesopores are still indispensable.
In addition, in addition to the unsolvable defects in the preparation of molecular sieves, the above schemes cannot well solve the problem of synergistic catalysis of Y and ZSM-5 molecular sieves.
This is mainly because the close contact and uniform dispersion of the two molecular sieves at the nanoscale cannot be achieved by the above synthesis method.

Method used

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  • A kind of method for preparing compound molecular sieve
  • A kind of method for preparing compound molecular sieve
  • A kind of method for preparing compound molecular sieve

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] Taking by weighing 1.4 gram mass concentration respectively is the tetrapropyl ammonium hydroxide solution of 20wt% and 1.5 gram H type Y molecular sieves (sample name Y 1 ; Si-Al ratio: 10.8). At room temperature, slowly and evenly drop 1.4 grams of the above-mentioned tetrapropylammonium hydroxide solution into the above-mentioned molecular sieve channel and impregnate evenly, and then transfer the obtained sample directly into a PTFE-lined stainless steel pressure-resistant reaction kettle with a volume of 5mL , then place the sealed reactor in a 150°C oven for crystallization for 24 hours to obtain the Y / ZSM-5 composite molecular sieve product (sample name ZSM-5 1 / Y 1 ;), the X-ray diffraction pattern and the scanning electron microscope figure of this sample are respectively as figure 1 and figure 2 shown.

Embodiment 2

[0041] Taking by weighing 1.7 gram mass concentration respectively is the tetrapropyl ammonium hydroxide solution of 20wt% and 1.5 gram Na type Y molecular sieves (sample name Y 2 ; Si-Al ratio: 10.8). At room temperature, slowly and uniformly drop 1.7 g of the above-mentioned tetrapropylammonium hydroxide solution into the above-mentioned molecular sieve channels to impregnate evenly, and then place the obtained sample at room temperature and dry in static air for 24 hours. Afterwards, the powder was transferred into a polytetrafluoro-lined stainless steel pressure-resistant reactor with a volume of 5mL, and then the sealed reactor was placed in a 150°C oven for crystallization for 24 hours to obtain the Y / ZSM-5 composite molecular sieve product (sample Name ZSM-5 2 / Y 2 ;), the X-ray diffraction pattern and the scanning electron microscope figure of this sample are respectively as image 3 and Figure 4 shown.

Embodiment 3

[0043] Take by weighing 1.0 gram mass concentration respectively and be the tetrapropyl ammonium hydroxide solution of 20wt% and 1.0 gram H type Y molecular sieve (sample name Y 3 ; Si-aluminum ratio: 15). At room temperature, slowly and evenly drop 1.0 g of the above-mentioned tetrapropylammonium hydroxide solution into the above-mentioned molecular sieve channel to impregnate evenly, and then transfer the obtained sample directly into a polytetrafluoro-lined stainless steel pressure-resistant reaction kettle with a volume of 5mL , then place the sealed reactor in a 150°C oven for crystallization for 24 hours to obtain the Y / ZSM-5 composite molecular sieve product (sample name ZSM-5 3 / Y 3 ;), the X-ray diffraction pattern and the scanning electron microscope figure of this sample are respectively as Figure 5 and Figure 6 shown.

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Abstract

The invention provides a method for preparing a composite molecular sieve. The method comprises steps as follows: an aqueous solution of alkali and a molecular sieve are impregnated and mixed uniformly in a mass ratio of the molecular sieve (dry basis), alkali and H2O being (0.1-1):(0.01-1):(0.5-5), a solid mixture obtained by the impregnation is subjected to or not subjected to drying pretreatment and then is crystallized for 0.1-120 h at the temperature of 50-250 DEG C, and a composite molecular sieve product is obtained. According to the method, the Y molecular sieve is subjected to alkalitreatment, partial skeleton structure of the molecular sieve is dissolved properly, and content of secondary pores of the Y molecular sieve is increased. Meanwhile, silicon aluminum species dissolvedfrom the molecular sieve skeleton and residual alkali liquor further interact and are subjected to nucleation and crystallization again under a certain hydrothermal condition, and the nano ZSM-5 molecular sieve is generated. The USY / ZSM-5 composite molecular sieve has higher heavy oil conversion capacity, higher light oil yield and higher low-carbon olefin selectivity when applied to the heavy oilcracking reaction.

Description

technical field [0001] The invention relates to a structural design method for molecular sieves, in particular to a method for reconstructing molecular sieve crystals by using an alkaline solution to partially dissolve the molecular sieves and further in-situ crystallization. Background technique [0002] Petroleum, as the world's largest energy source, not only provides gasoline, diesel, aviation kerosene and other fuel oils for human daily life, but also provides basic organic chemical raw materials such as olefins and aromatics. In recent years, in order to meet the growing demand for fuel consumption, my country's oil refining capacity has expanded rapidly, and the current capacity is already overcapacitated. But now, it has become an inevitable trend to improve energy efficiency and develop new technologies of clean and low-carbon energy. In the future, new energy production capacity will continue to increase. Therefore, in order to further expand the development spac...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B39/24C01B39/40C01B39/38
CPCC01B39/023C01P2002/72C01P2004/03C01P2006/17
Inventor 覃正兴沈焰丰刘欣梅王纯正白鹏郭海玲
Owner CHINA UNIV OF PETROLEUM (EAST CHINA)
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