Method for preparing low-sodium ZSM-5 molecular sieve and application of low-sodium ZSM-5 molecular sieve in xylene isomerization catalyst

A technology of ZSM-5 and molecular sieve, which is applied in molecular sieve catalysts, physical/chemical process catalysts, isomerization hydrocarbon production, etc., can solve the problems of xylene yield loss, process selectivity decline, high side reactions, etc., to reduce Production cost, improvement of isomerization activity, and effect of reducing emissions

Active Publication Date: 2022-05-03
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] There are still many defects in the comprehensive performance of the existing deethylation catalysts. The specific performance is that high-activity catalysts usually lead to relatively high side reactions, which reduces the process selectivity and causes the loss of xylene yield.

Method used

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  • Method for preparing low-sodium ZSM-5 molecular sieve and application of low-sodium ZSM-5 molecular sieve in xylene isomerization catalyst
  • Method for preparing low-sodium ZSM-5 molecular sieve and application of low-sodium ZSM-5 molecular sieve in xylene isomerization catalyst
  • Method for preparing low-sodium ZSM-5 molecular sieve and application of low-sodium ZSM-5 molecular sieve in xylene isomerization catalyst

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preparation example Construction

[0043] Adding a dispersant to the method for preparing low-sodium ZSM-5 molecular sieve of the present invention can optimize the morphology and surface acid distribution of the prepared molecular sieve, thereby improving the isomerization activity of the catalyst and obtaining higher p-xylene absorption. At the same time, the catalyst prepared by the method of the present invention can be used to prepare the catalyst without the ammonium exchange of the ZSM-5 molecular sieve, which not only reduces the discharge of nitrogen-containing wastewater, reduces the cost of catalyst preparation, but also reduces the pressure on environmental protection.

[0044] In one embodiment according to the present invention, the molar ratio of each material in the mixture to be crystallized is Na 2 O: SiO 2 :Al 2 o 3 :T:DA:H 2 O=(0.2-0.4): 1: (0.006-0.02): (0.01-0.12): (0.03-0.3): (20-50); wherein, sodium oxide / silicon oxide in the water glass described in (1) step The molar ratio is (2-4)...

Embodiment approach

[0059] In one embodiment, the shaped carrier loaded with the platinum component can be further subjected to steps such as drying, calcination under air atmosphere, and reduction. The temperature of the calcination can be preferably 400-550°C, hydrogen is preferably used as the reducing gas for the reduction, and the reduction temperature is 400-550°C, preferably 450-520°C.

[0060] The catalyst prepared by the present invention can be applied to 8 Xylene isomerization reaction of aromatic hydrocarbons, the isomerization reaction conditions can be: temperature 320-400°C, preferably 360-380°C, pressure 0.1-1.2MPa, preferably 0.2-1.1MPa, hydrogen / hydrocarbon molar ratio 0.2 -4.0, preferably 0.5-3.0, feed quality space velocity 4.0-15.0 hours -1 , preferably 6.0-12.0h -1 .

[0061] The present invention is further illustrated below by examples, but the present invention is not thereby limited in any way.

[0062] In the following examples and comparative examples of the presen...

example 1

[0067] (1) Preparation of low-sodium ZSM-5 molecular sieve

[0068] Add 58.5g water glass (SiO 2 The content is 24.01% by mass, Na 2 O content is 7.08% by mass, Al 2 o 3 Content is 0.2 mass %, the same below), 0.31g aluminum sulfate octadecahydrate, 2.33g tetraethylammonium chloride N (C 2 h 5 ) 4 + Cl - As template agent (T), 1.4g isopropanol, 64.8g deionized water mix homogeneously, obtain the mixture to be crystallized; Wherein the molar ratio of each material is Na 2 O: SiO 2 :Al2 o 3 :T:DA:H 2 O=0.28:1:0.007:0.06:0.1:25. Isopropanol is a dispersant.

[0069] The mixture to be crystallized was hydrothermally crystallized at 175°C for 35 hours, and the solid obtained after crystallization was washed with excess deionized water until the pH value of the eluate was 6-8, which was neutral, and then dried at 120°C for 6 Hours, low-sodium ZSM-5 molecular sieve was obtained, denoted as Z-1, its silica / alumina molar ratio was 100, Na 2 The O content is 0.45mol% (meas...

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Abstract

The invention relates to a method for preparing a low-sodium ZSM-5 molecular sieve and application of the low-sodium ZSM-5 molecular sieve in a xylene isomerization catalyst. According to the method for preparing the low-sodium ZSM-5 molecular sieve, the dispersing agent is added, and the morphology and surface acid distribution of the prepared molecular sieve can be optimized, so that the isomerization activity of the catalyst is improved, and higher p-xylene yield is obtained; meanwhile, the ZSM-5 molecular sieve can be used for preparing the catalyst without ammonium exchange, so that the discharge of nitrogen-containing wastewater is reduced, the preparation cost of the catalyst is reduced, and the environmental protection pressure is also relieved.

Description

technical field [0001] The invention relates to the field of xylene isomerization, in particular to a method for preparing low-sodium ZSM-5 molecular sieve and its application in xylene isomerization catalysts. Background technique [0002] Paraxylene (PX) is an important chemical raw material, mainly used in the production of terephthalic acid and terephthalic acid diester, and also used in coatings, dyes, pesticides and pharmaceuticals. With the development of these industries, the demand for PX is increasing rapidly. At present, the process technology for increasing the production of PX is mainly xylene isomerization, which is an important means to convert m-xylene and o-xylene with low utilization value into PX. [0003] In the prior art, the cost of separating ethylbenzene and xylene is relatively high, and ethylbenzene must be converted simultaneously during the xylene isomerization process. There are two different target directions for ethylbenzene conversion: conve...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B39/40B01J29/44B01J37/18B01J37/02C07C15/08C07C5/27
CPCC01B39/40B01J29/44B01J37/18B01J37/0201C07C5/2737C01P2002/72C01P2004/03B01J2229/186B01J2229/40C07C15/08Y02P20/52
Inventor 康承琳周震寰刘中勋盖月庭梁战桥阮迟王京岳欣王志强
Owner CHINA PETROLEUM & CHEM CORP
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