A kind of dealumination method of hydrogen and ammonium y, zsm-5, beta and sapo-34 molecular sieves

A technology of ZSM-5 and molecular sieve, which is applied in the direction of molecular sieve characteristic silicoaluminophosphate, molecular sieve and alkali exchange phosphate, crystalline aluminosilicate zeolite, etc. It can solve the problems of complicated preparation process and uneven degree of dealumination of molecular sieve , to achieve the effect of a wide range of dealumination and easy control of the degree

Inactive Publication Date: 2011-11-30
DALIAN UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0020] Dealumination of sodium-type molecular sieves with methyl chloride has the following two obvious deficiencies: one is that the NaCl produced by the reaction is deposited in the pores of the molecular sieve, affecting the CCl 4 Molecules diffuse in the pores of the molecular sieve, resulting in uneven dealumination of the molecular sieve
Second, after the dealumination reaction is completed, the NaCl deposited in the molecular sieve needs to be eluted, which complicates the preparation process
[0021] So far, there has been no study on the treatment of molecular sieves in forms other than the sodium form with methyl chloride vapor, illustrating the specific conditions of the reaction and industrial applicability

Method used

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  • A kind of dealumination method of hydrogen and ammonium y, zsm-5, beta and sapo-34 molecular sieves
  • A kind of dealumination method of hydrogen and ammonium y, zsm-5, beta and sapo-34 molecular sieves
  • A kind of dealumination method of hydrogen and ammonium y, zsm-5, beta and sapo-34 molecular sieves

Examples

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Effect test

example 1

[0047] Put 1 g (tabletting sieve into 20-40 mesh) hydrogen type Y molecular sieve (HY, SiO2 / Al2O3=5) in a quartz fixed bed reactor, and pass pure N2 at 500 ℃ to pretreat the zeolite 40 min to get rid of the water. The bed temperature was reduced to 250 ℃, and at this temperature, a CCl4 / N2 mixed gas with a CCl4 concentration of 5% was passed into the reactor at a flow rate of 300 ml / min to dealumulate the hydrogen-type Y molecular sieve 12 min. Then switch the above mixed gas to pure N2, raise the bed temperature from 250 ℃ to 400 ℃, and purge the sample for 40 min at a flow rate of 300 ml / min. The XRD patterns of the molecular sieve after dealumination and the original parent hydrogen type Y molecular sieve are as follows figure 1 Shown. It is measured that the dealumination amount of the hydrogen-type Y molecular sieve caused by the dealumination process is 173.5 mg (calculated as Al2O3).

example 2

[0049] Repeat example 1, but change the mixed gas used for dealumination of hydrogen type Y molecular sieve from CCl4 / N2 with a CCl4 concentration of 5% to CHCl3 / N2 with a CHCl3 concentration of 300 ppm, and at the same time, change the flow rate of the mixed gas At 600 ml / min, the dealumination time was extended from 12 min to 1 h. The molecular sieve obtained after dealumination is similar to the XRD pattern of the original parent hydrogen-type Y molecular sieve. The dealumination amount of the hydrogen-type Y molecular sieve caused by the dealumination process was measured to be 8.9 mg (calculated as Al2O3).

example 3

[0051] Repeat Example 1, but shorten the dealumination time of hydrogen type Y molecular sieve from 12 min to 4 min. It is measured that the dealumination amount of the hydrogen type Y molecular sieve caused by the dealumination process is 62.8 mg (calculated as Al2O3). The XRD patterns of the molecular sieve after dealumination and the original parent hydrogen type Y molecular sieve are as follows figure 2 Shown. The molecular sieve samples obtained after dealumination and the original precursor hydrogen-form Y molecular sieve samples were measured by pyridine adsorption infrared spectroscopy at 400 ℃. by image 3 It can be seen that the molecular sieve dealumed by this method has an infrared absorption at 1452 cm-1 nearly three times that of dealumination, which indicates that the molecular sieve dealumed by this method has a strong Lewis acid content that is nearly 3 times that of the original parent hydrogen type Y molecular sieve. Times. This result shows that the metho...

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Abstract

The invention relates to a preparation method of molecular sieve modified catalyst, and relates to a dealuminzation method of hydrogenous and ammonic Y,ZSM-5,beta and SAPO-34 molecular sieves. The method comprises steps that: methyl chloride vapor or a mixed gas containing methyl chloride vapor is delivered to the molecular sieves under a temperature of 80 to 500 DEG C for dealuminzing for 1 minute to 12 hours. According to the present invention, methyl chloride vapor or the mixed gas containing methyl chloride vapor is used for dealuminzing hydrogenous and ammonic Y,ZSM-5,beta and SAPO-34 molecular sieves. Compared to prior arts, with the method, dealuminzation scope is wide, dealuminzation degree is easy to control, and dealuminzation process can be completed in a short time. Therefore,the method is especially suitable for industrial dealuminzation of hydrogenous and ammonic molecular sieves. When a dealuminzation degree is low, the method can be applied in dealuminzation for adjusting acid properties (acid intensity and acid density) of the molecular sieves; when a dealuminzation degree is high, the method can be applied in dealuminzation for modifying the molecular sieve porestructural properties.

Description

Technical field [0001] The invention relates to a preparation method of a molecular sieve modified catalyst, in particular to a dealumination treatment method of hydrogen type and ammonium type Y, ZSM-5, β and SAPO-34 molecular sieves. Background technique [0002] Molecular sieves are widely used in catalytic reaction processes. Different catalytic reactions often require molecular sieves with different silicon to aluminum ratios. For example, the cracking of heavy oil requires molecular sieves with lower acid density but stronger acidity. The pore size of HY molecular sieve is larger, but the acid density is larger and the acidity is weaker. This requires post-treatment of HY molecular sieve for dealumination. Molecular sieves are also useful as catalysts or catalyst supports for reactions. Because molecular sieves hinder the diffusion of reactants and products, the lower diffusion rate of reactants or products in molecular sieve crystals directly affects the reaction rate. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B39/02C01B39/24C01B39/38C01B39/54C01B37/08
Inventor 王新平徐丹周玉强
Owner DALIAN UNIV OF TECH
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