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CN-121990588-A - ZSM-5 molecular sieve with nano porous structure and preparation method and application thereof

CN121990588ACN 121990588 ACN121990588 ACN 121990588ACN-121990588-A

Abstract

The invention provides a ZSM-5 molecular sieve with a nano porous structure, a preparation method and application thereof. The crystallinity of the ZSM-5 molecular sieve is more than 90%, the molar ratio of SiO 2 to Al 2 O 3 is (10-20): 1, and the ZSM-5 molecular sieve has good stability and catalytic activity and has important application value in the field of crude oil catalytic cracking.

Inventors

  • ZHANG ZHONGDONG
  • LIU CHAOWEI
  • LIU JIAXU
  • MENG FANFANG
  • WANG RUIPU
  • SUN ZHIGUO
  • ZHANG ZHAOQIAN
  • FAN HONGCHAO
  • YU QIANQIAN
  • LIU MEIJIA

Assignees

  • 中国石油天然气股份有限公司
  • 大连理工大学

Dates

Publication Date
20260508
Application Date
20241101

Claims (10)

  1. 1. A ZSM-5 molecular sieve with a nano porous structure is characterized in that the molar ratio of SiO 2 to Al 2 O 3 in the ZSM-5 molecular sieve is (10-20): 1, and the crystallinity of the ZSM-5 molecular sieve is more than 90%.
  2. 2. The ZSM-5 molecular sieve according to claim 1, wherein the ZSM-5 molecular sieve has a total specific surface area of 400m 2 /g-500m 2 /g, and/or, In the ZSM-5 molecular sieve, the specific surface area of micropores is 300m 2 /g-350m 2 /g, and/or, In the ZSM-5 molecular sieve, the specific surface area of the mesopores is 75m 2 /g-200m 2 /g, and/or, The ZSM-5 molecular sieve has micropores with a volume of 0.13cm 3 /g-0.14cm 3 /g and/or, In the ZSM-5 molecular sieve, the volume of mesopores is 0.24cm 3 /g-0.60cm 3 /g.
  3. 3. The ZSM-5 molecular sieve according to claim 1 or 2, characterized in that the ZSM-5 molecular sieve has a particle size of 500nm or less.
  4. 4. A method for preparing the ZSM-5 molecular sieve having a nano-porous structure according to any one of claims 1 to 3, comprising: 1) Forming mixed gel 1 by using an X molecular sieve, a silicon source and an alkali source, and performing first pre-crystallization treatment on the mixed gel 1 to obtain a pre-crystallized material 1; 2) Forming a mixed gel 2 by a silicon source, an aluminum source and a template agent, and performing second pre-crystallization treatment on the mixed gel 2 to obtain a pre-crystallized material 2; 3) Mixing the pre-crystallized material 1 and the pre-crystallized material 2, performing hydrothermal crystallization treatment to obtain a crystallized product, and sequentially performing filtration treatment, washing treatment, drying treatment and roasting treatment on the crystallized product to obtain the Na-type ZSM-5 molecular sieve; 4) And carrying out ammonium exchange treatment on the Na-type ZSM-5 molecular sieve, and then sequentially carrying out filtration treatment, washing treatment, drying treatment and roasting treatment to obtain the ZSM-5 molecular sieve.
  5. 5. The process according to claim 4, wherein the temperature is 25 to 100℃and the time is 24 to 48 hours in the first pre-crystallization treatment and/or the second pre-crystallization treatment, and/or, In the hydrothermal crystallization treatment, the temperature is 120-190 ℃ and the time is 8-120h.
  6. 6. The process according to claim 4, wherein the ammonium exchange treatment comprises an ammonium exchange treatment with an aqueous solution of 0.4 to 0.8M ammonium chloride and/or, In the ammonium exchange treatment, the temperature is 30-60 ℃ and the exchange times are 1-5.
  7. 7. The method according to claim 4, wherein the baking treatment is performed at a temperature of 450 to 650 ℃ for a time of 3 to 7 hours.
  8. 8. The method according to claim 4, wherein the molar ratio of SiO 2 、Al 2 O 3 、Na 2 O to water in the mixed gel 1 is 1 (0.05-0.2): 0.1-0.5): 30-50, and/or, In the mixed gel 2, the mol ratio of SiO 2 、Al 2 O 3 to template agent to water is 1 (0.05-0.033) (0.5-0.05) (30-180).
  9. 9. The method according to claim 4, wherein the silicon source comprises at least one of sodium silicate nonahydrate, ethyl orthosilicate, water glass, solid silica gel, white carbon black, silica sol, and/or, The aluminum source comprises at least one of aluminum hydroxide, sodium metaaluminate, aluminum isopropoxide, boehmite, aluminum sulfate and aluminum powder, and/or, The alkali source comprises at least one of sodium hydroxide, potassium hydroxide and ammonia water, and/or, The template agent comprises at least one of methylamine, ethylenediamine, n-propylamine, n-butylamine and tetrapropylammonium hydroxide.
  10. 10. Use of the nanoporous structured ZSM-5 molecular sieve as defined in any one of claims 1 to 3 in a catalytic cracking reaction of 1,3, 5-triisopropylbenzene.

Description

ZSM-5 molecular sieve with nano porous structure and preparation method and application thereof Technical Field The invention belongs to the technical field of catalysis, and particularly relates to a ZSM-5 molecular sieve with a nano porous structure, and a preparation method and application thereof. Background Ethylene, propylene and butene are basic raw materials for petrochemical industry, and at present, ethylene, propylene and butene are mainly obtained by steam cracking technology. However, the steam cracking technology has the problems of high energy consumption, high construction cost, unreasonable product structure and the like, not only affects the economical efficiency of ethylene, propylene and butylene production, but also cannot meet the environmental protection requirement. In order to overcome the defects of the steam cracking technology, the catalytic cracking technology is used for producing ethylene, propylene and butylene, the catalytic cracking technology takes a solid acid catalyst as a medium, and petroleum hydrocarbon is converted into low-carbon olefin such as ethylene, propylene and the like under the high temperature condition, and partial aromatic hydrocarbon products are coproduced. Compared with the steam cracking technology, the catalytic cracking technology has the advantages of capability of reducing the temperature (about 200 ℃) of the cracking reaction, good raw material adaptability, flexible product scheme, mild operating conditions and low cost, and has important significance in the aspect of producing low-carbon olefin, light oil or a mixture (BTX) of three aromatic hydrocarbons of toluene and xylene. The molecular sieve catalyst is the core of the catalytic cracking technology, wherein ZSM-5 molecular sieve is used as an important component of the molecular sieve catalyst, and has a unique pore structure and proper acidity, so that the molecular sieve catalyst is widely applied to the catalytic cracking technology. However, existing ZSM-5 molecular sieves have poor catalytic activity and stability. Therefore, how to provide a ZSM-5 molecular sieve with high catalytic activity and excellent stability is a technical problem to be solved in the field. Disclosure of Invention The ZSM-5 molecular sieve with the nano porous structure provided by the invention has high crystallinity and low silicon-aluminum ratio, and is beneficial to improving the catalytic activity and stability of the ZSM-5 molecular sieve. The invention also provides a preparation method of the ZSM-5 molecular sieve with the nano porous structure, and the ZSM-5 molecular sieve obtained by the preparation method has better stability and catalytic activity. The invention also provides application of the ZSM-5 molecular sieve with the nano porous structure in the catalytic cracking reaction of the 1,3, 5-triisopropylbenzene, and the ZSM-5 molecular sieve has better catalytic activity and stability and further has better conversion rate of the 1,3, 5-triisopropylbenzene. In a first aspect, the invention provides a ZSM-5 molecular sieve with a nano-porous structure, wherein the mole ratio of SiO 2 to Al 2O3 in the ZSM-5 molecular sieve is (10-20): 1, and the crystallinity of the ZSM-5 molecular sieve is more than 90%. The ZSM-5 molecular sieve as described above, wherein the ZSM-5 molecular sieve has a total specific surface area of 400m 2/g-500m2/g, and/or wherein the ZSM-5 molecular sieve has a micropore specific surface area of 300m 2/g-350m2/g, and/or wherein the ZSM-5 molecular sieve has a mesopore specific surface area of 75m 2/g-200m2/g, and/or wherein the ZSM-5 molecular sieve has a micropore volume of 0.13cm 3/g-0.14cm3/g, and/or wherein the ZSM-5 molecular sieve has a mesopore volume of 0.24cm 3/g-0.60cm3/g. The ZSM-5 molecular sieve is prepared according to the method, wherein the particle size of the ZSM-5 molecular sieve is less than or equal to 500nm. In a second aspect, the present invention provides a method for preparing the ZSM-5 molecular sieve, comprising: 1) Forming mixed gel 1 by using an X molecular sieve, a silicon source and an alkali source, and performing first pre-crystallization treatment on the mixed gel 1 to obtain a pre-crystallized material 1; 2) Forming a mixed gel 2 by a silicon source, an aluminum source and a template agent, and performing second pre-crystallization treatment on the mixed gel 2 to obtain a pre-crystallized material 2; 3) Mixing the pre-crystallized material 1 and the pre-crystallized material 2, performing hydrothermal crystallization treatment to obtain a crystallized product, and sequentially performing filtration treatment, washing treatment, drying treatment and roasting treatment on the crystallized product to obtain the Na-type ZSM-5 molecular sieve; 4) And carrying out ammonium exchange treatment on the Na-type ZSM-5 molecular sieve, and then sequentially carrying out filtration treatment, washing treatment, drying treatment and roasting treatment