Method for preparing SSZ-13 molecular sieve membrane through steam-assisted conversion

A molecular sieve and steam technology, used in molecular sieve compounds, chemical instruments and methods, inorganic chemistry, etc., can solve the problems of high pressure, unsafe, large amount, etc., and achieve the goal of improving synthesis repeatability, reducing solid waste and improving safety. Effect

Active Publication Date: 2021-04-13
NANJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The traditional hydrothermal synthesis method has the following disadvantages: a large amount of synthetic sol is required and a large amount of solid waste is generated at the same time; the sol is easy to settle and the concentration is uneven, which affects the repeatability of membrane synthesis; the reaction pressure is high and unsafe, etc.
Many unfavorable factors hinder the industrial application of molecular sieve membranes

Method used

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  • Method for preparing SSZ-13 molecular sieve membrane through steam-assisted conversion
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  • Method for preparing SSZ-13 molecular sieve membrane through steam-assisted conversion

Examples

Experimental program
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Effect test

Embodiment 1

[0034] A kind of preparation method of the SSZ-13 molecular sieve membrane of steam assisted reforming, concrete steps are as follows:

[0035] (1) Preparation of SSZ-13 molecular sieve seed crystals:

[0036] Sodium hydroxide (NaOH, 98%), N,N,N-trimethyl-1-adamantyl ammonium hydroxide (TMAdaOH, 25wt%, SDA), deionized water, aluminum hydroxide (Al(OH) 3 ,99%) and silica sol (TM-40,40%) mixed to obtain molecular sieve synthesis sol molar ratio is SiO 2 / Al 2 o 3 =200,Na 2 O / SiO 2 =0.1,H 2 O / SiO 2 = 44, TMAdaOH / SiO 2 = 0.4. After aging at room temperature for 8 hours, the reaction sol was poured into a stainless steel reactor with a Teflon lining, and reacted in an oven at 433K for 96 hours. The reaction product is washed with deionized water, centrifuged at high speed for 3-4 times, and finally the obtained solid molecular sieve particles are dried in a 373K oven.

[0037] (2) Pretreatment of porous supports:

[0038] Using a porous alumina tube as a support, add 0.1...

Embodiment 2

[0046] The preparation method of SSZ-13 molecular sieve film is basically the same as that of Example 1, wherein the preparation process of step (1) and (3) film and seed crystal is different in that the H in the synthetic sol 2 O / SiO 2 =20; the added amount of the sol for membrane synthesis is 1.0 g (1 vol% of the volume of the reaction kettle). The prepared film is marked as M2, and its SEM surface and cross-sectional images are shown in Figure 4 a and 4b. membrane M2 in N 2 / CH 4 The separation performance of the system is shown in Table 1.

Embodiment 3

[0048] The preparation method of molecular sieve film is basically the same as that of Example 1, wherein the difference in the preparation process of step (1) and (3) film and seed crystal is that the H of synthetic sol 2 O / SiO 2 =500, the sol was aged at room temperature for 24h. The prepared membrane is marked as M3, and its SEM surface and cross-section are as follows Figure 4 c and 4d are shown. membrane M3 in N 2 / CH 4 The separation performance of the system is shown in Table 1.

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Abstract

The invention discloses a method for preparing an SSZ-13 molecular sieve membrane through steam-assisted conversion. The method comprises the following steps: (1) preparing a SSZ-13 molecular sieve seed crystal; (2) pretreating a porous support, namely coating a porous support with a crystal seed layerhaving a density of 1-300 [ mu ] g/cm<2> ; and (3) preparing a SSZ-13 molecular sieve membrane, namely adding a small amount of synthetic sol without contacting with the pretreated support, heating the sol, vaporizing and transferring heat, and matching with a small amount of structure directing agent and water to pre-coat the sol to perform crystallization, thereby forming the molecular sieve membrane. According to the invention, more than 90% of synthetic sol can be saved through steam-assisted conversion, the synthesis operation process is safe, and the discharge of reaction waste liquid is reduced. The method is economical, safe and environment-friendly, and the prepared membrane is excellent in performance and can be applied to industrial preparation of the molecular sieve membrane.

Description

technical field [0001] The invention relates to a method for preparing molecular sieve membranes, in particular to a method for preparing SSZ-13 molecular sieve membranes by steam-assisted transformation, and belongs to the technical field of molecular sieve membrane materials. Background technique [0002] The membrane separation process has the advantages of low energy consumption, small footprint, and cost-effectiveness. SSZ-13 molecular sieve has a chabazite-type (CHA) 8-membered ring channel structure, and its 8-membered ring channel size is Due to its excellent molecular sieving ability, it is used to separate slightly larger molecules middle separation with and other small molecule species. SSZ-13 molecular sieve membrane has great application potential in the field of natural gas purification and removal of carbon dioxide and nitrogen impurity gases. [0003] Most of the existing SSZ-13 molecular sieve membranes are synthesized by hydrothermal secondary synth...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B39/04C01B37/00
CPCC01B39/04C01B37/00C01P2004/03C01P2002/72Y02C20/40
Inventor 周荣飞李艳美刘宇超柳波王斌
Owner NANJING UNIV OF TECH
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