Preparation method of small-crystal-grain SAPO-34 molecular sieve

A technology of SAPO-34 and molecular sieve, which is applied in the direction of molecular sieve characteristic silicoaluminophosphate, molecular sieve and alkali exchange phosphate, etc., can solve the problem of lack of further research on the influence of aging time on product properties, and achieve excellent catalytic effect and uniform dispersion , the effect of small grain size

Inactive Publication Date: 2013-10-02
天津众智科技有限公司
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Problems solved by technology

The traditional method of preparing SAPO-34 molecular sieve is the hydrothermal synthesis method. Previous literatures have studied the hydrothermal synthesis of SAPO-34 from different angles, mainly focusing on the properties and proportions of raw materials, template agents, modification treatments, and crystallization conditions. etc. on the synthesis of SAPO-34, but there is a lack of further research on the influence of factors such as aging temperature and aging time on product properties

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  • Preparation method of small-crystal-grain SAPO-34 molecular sieve

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preparation example Construction

[0023] A kind of preparation method of small-grain SAPO-34 molecular sieve adopts dynamic hydrothermal method to synthesize series SAPO-34 molecular sieve, and the steps are as follows:

[0024] ⑴First, add a certain amount of aluminum source (pseudoboehmite, with a content of 65% to 75%) into deionized water under stirring at room temperature, and then add a certain amount of silicon source (neutral silica sol, with a content of 40 %) and stir well. Then slowly add a certain amount of phosphorus source (orthophosphoric acid, the content is 85%), and continue to stir evenly; then slowly add a certain amount of template agent (tetraethylammonium hydroxide aqueous solution, the content is 25%), increase the stirring speed to make solution into a homogeneous gel.

[0025] (2) Stir the homogeneous gel on a homogenizer at 10,000 rpm for 30 minutes, then place it in an oven at different temperatures for aging for a certain period of time;

[0026] (3) Transfer the gel to a dynamic...

Embodiment 1

[0034] A preparation method of small grain SAPO-34 molecular sieve, the steps are as follows:

[0035] (1) First, add 22.76 grams of pseudoboehmite (65% to 75% content) into 99.83 ml deionized water while stirring at room temperature, then add 3.81 ml neutral silica sol (40% content) and stir well. Slowly add 20.53 milliliters of orthophosphoric acid (content is 85%), continue to stir evenly. Then slowly add 172.79 milliliters of tetraethylammonium hydroxide aqueous solution (content is 25%), increase stirring speed to make the solution into a uniform gel.

[0036] (2) Stir the homogeneous gel on a homogenizer at 10,000 rpm for 30 minutes, then place it in a refrigerator (about 3-5°C) for 18 hours of aging;

[0037] (3) Transfer the gel to a dynamic high-pressure reactor, set a certain speed, and crystallize at 200°C for 28 hours. After the crystallization is complete, cool it quickly with cold water. Finally, the reacted mixture is separated, washed, and dried. The molecula...

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Abstract

The invention relates to a preparation method of a small-crystal-grain SAPO-34 molecular sieve. A gel formed by an aluminum source, a phosphorus source, a silicon source, a solvent and a template is subjected to aging before crystallization, wherein the aging temperature is 1-14 DEG C, and the aging time is 30 minutes to 50 hours. The SAPO-34 molecular sieve prepared by aging has the characteristics of higher specific area, small grain size and uniform dispersion, and the average grain size is less than 2 mu m. The acid density of the product obtained by the special aging step is higher than that of the product which is not subjected to aging or subjected to room-temperature aging. The molecular sieve has excellent catalytic effect relative to the unaged product in MTO catalytic reaction.

Description

technical field [0001] The invention belongs to a method for preparing molecular sieves, and relates to a method for preparing a new SAPO-34 molecular sieve, in particular to a method for preparing a small-grain SAPO-34 molecular sieve. Background technique [0002] Silicoaluminophosphate molecular sieve (SAPO-n) made of SiO 2 , AlO 2 - and PO 2 + Microporous crystal composed of three tetrahedral units, among which SAPO-34 is a molecular sieve with small pore structure, which has excellent shape selectivity. In 1984, Union Carbide Corporation of the United States developed the series of silicoaluminophosphate (SAPO-n) molecular sieves. Due to the high selectivity of SAPO-34 molecular sieves to ethylene and propylene, it is recognized as the best catalyst for methanol to olefins. SAPO-34 molecular sieves The small pore structure, moderate acidity and good hydrothermal stability are the main reasons for the good catalytic performance of methanol to olefins. The tradition...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B37/08C01B39/54
Inventor 常云峰丁月
Owner 天津众智科技有限公司
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