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Preparation and application of hzsm-5/sapo-11 core-shell molecular sieve

A technology of SAPO-11 and core-shell molecular sieves, which is applied in the field of catalyst preparation and application, can solve the problems of industrial catalyst regeneration, catalytic activity suppression, and aggravated catalysts, so as to achieve the improvement of weak acid synergistic aromatization activity, the reduction of diffusion resistance, The effect of simplifying the crystallization process

Active Publication Date: 2018-11-23
TAIYUAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The aromatization reaction of low-carbon hydrocarbons is a synergistic catalytic reaction between strong and weak acids. If the acidity is too strong, it will aggravate the cracking side reactions on the surface of the catalyst and cause coking and deactivation. If the acidity is too weak, the catalytic activity will be inhibited.
Therefore, the current research on low-carbon hydrocarbon aromatization catalysts is mainly concentrated on the modified HZSM-5 zeolite molecular sieve, including metal modification such as Zn and Ga on the strong solid acid catalyst HZSM-5, acid-base modification, high temperature treatment and steam Treatment, etc., by modifying the acidity and pore structure of the molecular sieve, and then improving the catalytic activity and anti-coking deactivation ability, among which the acid and alkali modification process destroys the regular pore structure of the molecular sieve to a certain extent, which is very important for the regeneration of industrial catalysts. make an impact

Method used

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  • Preparation and application of hzsm-5/sapo-11 core-shell molecular sieve
  • Preparation and application of hzsm-5/sapo-11 core-shell molecular sieve
  • Preparation and application of hzsm-5/sapo-11 core-shell molecular sieve

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0052] Preparation of Nuclear Phase Molecular Sieve HZSM-5

[0053] Under hydrothermal system and alkaline conditions, NaZSM-5 was prepared by using white carbon black as the silicon source, aluminum isopropoxide as the aluminum source, and tetrapropylammonium hydroxide as the template. The molar ratio of the initial sol was as follows: n (TPAOH): n (SiO 2 ): n ( Al 2 o 3 ): n (Na 2 O): n (H 2 O)=0.2:1.0:0.014:0.09:35. Then put NaZSM-5 in 1M NH 4 NO 3In the aqueous solution, stirred at constant temperature for 2 hours, cooled, filtered, and dried. This process was repeated three times, and finally placed in a muffle furnace at 520°C for 6 hours to obtain HZSM-5.

[0054] Cationic Reagent Modification Pretreatment Stage of Nuclear Phase Molecular Sieve HZSM-5

[0055] Weigh 2.391gHZSM-5 molecular sieve (silicon-aluminum molar ratio n (Si / Al) is 38) Add 100mL of deionized water, ultrasonically shake at 800W, 60Hz for 20min, prepare 127.15mL of 1% PDDA solution, add ...

Embodiment 2~6

[0066] In Examples 2-6, core-shell molecular sieves CZS-2-CZS-6 were synthesized according to the method similar to Example 1 under the conditions listed in Table 1 and Table 2.

[0067]

[0068]

Embodiment 7~10

[0070] In Examples 7-10, core-shell molecular sieves CZS-7-CZS-9 were synthesized according to the method similar to Example 1 under the conditions listed in Table 3 and Table 4.

[0071]

[0072]

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Abstract

The invention provides a preparation method of an HZSM-5 / SAPO-11 core-shell molecular sieve with a micro-mesoporous hierarchical porous structure by cation reagent-assisted two-stage crystallization. The preparation method is characterized in that HZSM-5 modified with a cation reagent adsorbs SAPO-11 nanocrystal in a low-temperature crystallization liquid; and after fine-tuning of content of the low-temperature crystallization liquid, in-situ high-temperature crystallization is carried out such that SAPO-11 is cross-linked and grows on the surface of HZSM-5 until covering the whole HZSM-5 molecular sieve crystal. Then, the hierarchical porous HZSM-5 / SAPO-11 core-shell molecular sieve with single crystal HZSM-5 molecular sieve as the core and polycrystalline SAPO-11 molecular sieve as the shell is prepared, wherein the shell phase is formed by accumulation of 30-50nm SAPO-11 nanocrystal with uniformly-distributed intracrystalline pores of about 8nm and has a micro-mesoporous hierarchical porous structure. the core-shell molecular sieve is used as a catalyst to be applied in an isobutane isomerization reaction.

Description

technical field [0001] The invention belongs to the field of catalyst preparation and application, in particular to a preparation method of a core-shell molecular sieve HZSM-5 (core) / SAPO-11 (shell) with a hierarchical pore structure and its application in isobutane aromatization reaction . Background technique [0002] Benzene, toluene, ethylbenzene and xylene (BTEX), as the main products of aromatization of low-carbon hydrocarbons, are important chemical basic raw materials, widely used in synthetic fibers, resins, rubber and various fine chemicals, and are in great demand At the same time, toluene and xylene are becoming more and more popular as important blending components for the production of high-octane gasoline. Therefore, low-carbon hydrocarbon aromatization technology can not only realize the value-added utilization of low-carbon hydrocarbons, but also alleviate the tight supply of aromatics, which has strong practical significance. [0003] The aromatization re...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J29/85C07C2/76C07C15/02
CPCB01J29/005B01J29/40B01J29/85B01J2229/34B01J2229/62C07C2/76C07C15/02
Inventor 张瑞珍温少波邢普赵欣
Owner TAIYUAN UNIV OF TECH