Dealuminzation method of hydrogenous and ammonic Y,ZSM-5,beta and SAPO-34 molecular sieves

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

Inactive Publication Date: 2012-12-26
DALIAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0019] 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
[0020] 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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  • Dealuminzation method of hydrogenous and ammonic Y,ZSM-5,beta and SAPO-34 molecular sieves
  • Dealuminzation method of hydrogenous and ammonic Y,ZSM-5,beta and SAPO-34 molecular sieves
  • Dealuminzation method of hydrogenous and ammonic Y,ZSM-5,beta and SAPO-34 molecular sieves

Examples

Experimental program
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Effect test

example 1

[0046] Put 1 g of hydrogen-type Y molecular sieve (HY, SiO2 / Al2O3=5) (pressed and sieved into 20-40 mesh) in a quartz fixed-bed reactor, and feed pure N2 at 500 °C to pretreat the zeolite for 40 min to remove the moisture. Lower the bed temperature to 250 ° C, at this temperature, the CCl4 concentration of 5% CCl4 / N2 mixed gas is passed into the reactor at a flow rate of 300 ml / min to dealuminate the hydrogen-type Y molecular sieve12 min. Then the above mixed gas was switched to pure N2, the bed temperature was raised from 250 °C to 400 °C, and the sample was purged at a flow rate of 300 ml / min for 40 min. The XRD pattern of the molecular sieve after the gained dealumination and the original parent hydrogen type Y molecular sieve is as follows: figure 1 shown. It is measured that the dealumination process results in a dealumination amount of the hydrogen-type Y molecular sieve of 173.5 mg (calculated as Al2O3).

example 2

[0048] Repeat example 1, but the mixed gas that will be used for the dealumination of hydrogen type Y molecular sieve is that the CCl4 / N2 of 5% is changed to the CHCl3 / N2 that the concentration of CHCl3 is 300 ppm by the concentration of CCl4 for the dealumination of hydrogen type Y molecular sieve, meanwhile, the flow rate of mixed gas is changed to 600 ml / min, the dealumination time was extended from 12 min to 1 h. The XRD pattern of the obtained molecular sieve after dealumination is similar to that of the original parent hydrogen type Y molecular sieve. It was measured that the dealumination process resulted in a dealumination amount of hydrogen type Y molecular sieve of 8.9 mg (calculated as Al2O3).

example 3

[0050] Repeat Example 1, but shorten the dealumination treatment time of hydrogen type Y molecular sieve from 12 min to 4 min. It was measured that the dealumination process resulted in a dealumination amount of hydrogen type Y molecular sieve of 62.8 mg (calculated as Al2O3). The XRD pattern of the molecular sieve after the gained dealumination and the original parent hydrogen type Y molecular sieve is as follows: figure 2 shown. The obtained dealuminated molecular sieve samples and the original parent hydrogen-type Y molecular sieve samples were measured by pyridine adsorption infrared spectrum at 400 ℃. Depend on image 3 It can be seen that the infrared absorption of the dealuminated molecular sieve by this method is nearly 3 times that of the dealuminated molecular sieve at 1452 cm-1, which indicates that the strong Lewis acid content of the dealuminated molecular sieve by this method is nearly 3 times that of the original parent hydrogen-type Y molecular sieve. times...

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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 ratios of silicon to aluminum. For example, heavy oil cracking reactions require molecular sieves with lower acid density but stronger acidity. HY molecular sieve has larger pore size, but higher acid density and weaker acidity. This requires the HY molecular sieve to be dealuminated after treatment. There are also reactions in which molecular sieves are used as catalysts or catalyst supports. Due to the hindering effect of molecular sieves on the diffusion of reactants and products, the lower diffusion rate of reactants or products in molecular sieve crystals directly af...

Claims

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Application Information

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Patent Type & Authority Patents(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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