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Preparation method of composite molecular sieve catalyst of four-layer structure

A composite molecular sieve and molecular sieve technology, which is applied in the direction of molecular sieve catalysts, chemical instruments and methods, physical/chemical process catalysts, etc., can solve the problem that the selectivity of molecular sieves cannot be well utilized, poor molecular accessibility, and large molecular sieve grains and other problems, to achieve the effect of improving catalytic activity and selectivity, improving shape selectivity, and prolonging catalyst life

Active Publication Date: 2015-04-22
广州光义化工科技发展有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

There are also some problems with this technology. First, due to mechanical mixing, the crystal grains of molecular sieves are relatively large, and one crystal grain will contain thousands of unit cells of the same type of molecular sieve. The reactant molecules must be transferred from one molecular sieve to another Molecular sieves are very difficult to approach
That is, the accessibility of molecules is very poor, and the selectivity of molecular sieves cannot be fully utilized.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Preparation of Y-type molecular sieve: At 25°C, take 400mL of water glass, 250mL of high-alkali sodium aluminum meta-acid, 580mL of sodium hydroxide solution, 150mL of distilled water, and 120mL of directing agent solution, and mix them to adjust the pH value of the reaction mixture to 12.0 , control the temperature at 90°C, and crystallize for 5 hours to obtain Y-type molecular sieve microcrystals, which are cooled, filtered, washed, dried, and used;

[0019] Preparation of cerium-modified Y-type molecular sieve: Prepare cerium nitrate aqueous solution, add the Y-type molecular sieve obtained in step a) into the solution, stir, fully impregnate for 2 hours, filter, dry, and roast at 450°C for 2 hours, then use CeO 2 Calculated, CeO contained in Y-type molecular sieve 2 1.8wt%;

[0020] Preparation of ZSM-10 molecular sieve in the middle layer: according to the molar ratio: SiO 2 :A1 2 o 3 :MgO:KO:TPAOH:H 2 O=26:1:3.6:5.2:4.4:20, formulated to contain SiO 2 Then a...

Embodiment 2

[0025] The same preparation steps as in Example 1 were used to obtain the intermediate product ZSM-10 composite molecular sieve loaded with rhodium particles. The concentration and crystallization time of the shell layer growth solution are adjusted to obtain a catalyst product. The thickness of the outermost layer of the catalyst, ZSM-10, is 250 nm.

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PUM

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Abstract

The invention discloses a preparation method of a composite molecular sieve catalyst of two kinds of molecular sieves of a four-layer structure. A double-layer completely-wrapped type composite molecular sieve is formed by wrapping a cerium-modified core Y-type molecular sieve, a rhodium-loaded ZSM-10 middle layer and a shell ZSM-10. By means of the structure, reactant molecules can approach from one kind of molecular sieves to another kind of molecular sieves, so the selectivity and yield of propylene are improved. By the adoption of the catalyst structure, the activity and stability of the catalyst are effectively improved, the shape selectivity and anti-poisoning performance of the catalyst are improved, and the service life of the catalyst is prolonged.

Description

technical field [0001] The invention relates to a composite molecular sieve catalyst used for preparing propylene, in particular to a multilayer structure bimolecular sieve catalyst and a preparation method thereof. Background technique [0002] Propylene is one of the important organic raw materials next to ethylene. With the rapid development of the national economy, the demand for it is also increasing. At present, the supply of propylene in our country is in short supply. The existing methods for preparing propylene mainly include hydrocarbon steam cracking and catalytic cracking. The continuous improvement of catalysts for preparing propylene is also the main direction of research by technicians in this field. [0003] Composite molecular sieve catalyst is a commonly used catalyst type in this field. At present, there are many kinds of composite molecular sieve catalysts, but most of them adopt the method of mechanical mixing, mixing two molecular sieves together, and t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J29/80B01J35/02C07C11/06C07C4/06B01J35/00
CPCY02P20/52
Inventor 叶澄
Owner 广州光义化工科技发展有限公司