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CN-122010138-A - Na-type ZSM-5 molecular sieve, synthesis method thereof and oil catalytic cracking catalyst

CN122010138ACN 122010138 ACN122010138 ACN 122010138ACN-122010138-A

Abstract

The invention provides a Na-type ZSM-5 molecular sieve, a synthesis method thereof and an oil catalytic cracking catalyst. The synthesis method comprises the steps of drying and roasting a silicon source and an aluminum source to obtain an activated silicon source and an activated aluminum source, adding a sodium-containing alkali source into water to obtain a sodium-containing alkali solution, grinding the activated silicon source, adding the sodium-containing alkali solution into the sodium-containing alkali solution, performing first stirring to obtain molecular sieve gel I, adding the activated aluminum source into the molecular sieve gel I, performing second stirring to obtain molecular sieve gel II, dripping a liquid guiding agent into the molecular sieve gel II, performing third stirring to obtain molecular sieve gel III, crystallizing the molecular sieve gel III, and cooling, suction filtering, washing and drying to obtain the Na-type ZSM-5 molecular sieve. The ZSM-5 molecular sieve has high crystallinity, high specific surface area, large pore volume and most of microporous structure, and no organic template agent or seed crystal is added in the synthesis process, so that the post-treatment process of organic matters is omitted.

Inventors

  • ZHANG ZHONGDONG
  • YU QIANQIAN
  • XIE BAOZHEN
  • MENG FANFANG
  • SUN ZHIGUO
  • WANG RUIPU
  • ZHANG ZHAOQIAN
  • SHI DEJUN
  • CHEN QI
  • CHI KEBIN

Assignees

  • 中国石油天然气股份有限公司

Dates

Publication Date
20260512
Application Date
20241112

Claims (11)

  1. 1. A method for synthesizing a Na-type ZSM-5 molecular sieve, wherein the method comprises the following steps: (1) Drying and roasting the silicon source and the aluminum source to obtain an activated silicon source and an activated aluminum source; (2) Grinding the activated silicon source, adding the silicon source into the sodium-containing alkaline solution, and carrying out first stirring to obtain molecular sieve gel I; (3) Adding the activated aluminum source into the molecular sieve gel I, and performing second stirring to obtain molecular sieve gel II; (4) Dropwise adding the liquid guiding agent into the molecular sieve gel II, and carrying out third stirring to obtain molecular sieve gel III; (5) Crystallizing the molecular sieve gel III, cooling, filtering, washing and drying to obtain a Na-type ZSM-5 molecular sieve; Wherein the molecular sieve gel III satisfies the molar ratio of SiO 2 :Al 2 O 3 :Na 2 O:H 2 O= (25-50) 1 (3-15) 800-2000, the molar ratio of the silicon source is calculated by SiO 2 , the molar ratio of the aluminum source is calculated by Al 2 O 3 , and the molar ratio of the sodium-containing alkali source is calculated by Na 2 O; The addition amount of the liquid guiding agent is 5-20% of the total weight of the silicon source added in the molecular sieve gel III.
  2. 2. The synthetic method of claim 1, wherein the silicon source comprises one or a combination of two or more of white carbon black, tetraethyl orthosilicate, silica gel, silica sol, sodium silicate.
  3. 3. The synthesis method according to claim 2, wherein the silicon source is an industrial grade raw material, and the content of SiO 2 in a dry basis of the industrial grade raw material is 92% or more.
  4. 4. The synthetic method of claim 1, wherein the aluminum source comprises one or a combination of two or more of pseudoboehmite, aluminum hydroxide, sodium metaaluminate, aluminum isopropoxide, aluminum sulfate, boehmite.
  5. 5. The synthesis method according to claim 1, wherein the liquid director is obtained by dissolving the sodium-containing alkali source and the activated silicon source in step (1) in water and stirring the mixture for the fourth time; The molar ratio of each component in the liquid guiding agent is SiO 2 :Na 2 O:H 2 O=1 (0.2-2) to (8-15).
  6. 6. The synthesis method according to claim 1, wherein the firing temperature is 500-800 ℃ and the firing time is 4-8h.
  7. 7. The synthetic method of claim 1, wherein the crystallization temperature is 90-175 ℃ and the crystallization time is 24-80h.
  8. 8. The synthetic method according to claim 1 or 5, wherein the first stirring condition is uniform stirring at 25-75 ℃ for 4-8 hours; the second stirring condition is that stirring is carried out for 1-3h at 25-75 ℃; the third stirring condition is that stirring is carried out for 1-3h at 25-75 ℃; And the fourth stirring condition is that stirring is carried out at a constant speed for 4-8h at the temperature of 40-80 ℃.
  9. 9. A Na-type ZSM-5 molecular sieve prepared by the synthesis method of any one of claims 1-8.
  10. 10. The Na-type ZSM-5 molecular sieve according to claim 9, wherein the Na-type ZSM-5 molecular sieve has a micropore specific surface area of 171-352m 2 /g and a micropore volume of 0.07-0.13cm 3 /g.
  11. 11. An oil catalytic cracking catalyst prepared by taking the Na-type ZSM-5 molecular sieve according to claim 9 or 10 as a raw material; the oil catalytic cracking catalyst comprises 5-45 parts by mass of H-type ZSM-5 molecular sieve and 55-95 parts by mass of matrix; The H-type ZSM-5 molecular sieve is obtained by carrying out ammonium exchange and roasting on the Na-type ZSM-5 molecular sieve.

Description

Na-type ZSM-5 molecular sieve, synthesis method thereof and oil catalytic cracking catalyst Technical Field The invention belongs to the technical field of molecular sieve preparation, and in particular relates to a Na-type ZSM-5 molecular sieve, a synthesis method thereof and an oil catalytic cracking catalyst. Background Low-carbon olefins (ethylene, propylene, butylene, 1-3 butadiene, etc.), particularly ethylene and propylene, are important basic raw materials for producing downstream organic chemical products. At present, the steam cracking process is still mainly used for producing the low-carbon olefin, but the reaction temperature of the steam cracking process is generally higher than 750 ℃, so that the emission of CO 2 is large, the yield of the low-carbon olefin is low, the equipment stability is poor, the service life is short, the production cost is increased, and the high energy consumption and the high emission in the production process are caused. In the existing series of technical processes for producing low-carbon olefins, the catalytic cracking technology has attracted more and more attention because of the reduction of reaction temperature, reduction of CO 2 emission, realization of adjustable product distribution and selectivity, and easier realization of process production conditions. The heart of catalytic cracking is the development of catalysts. The solid acid catalyst (such as ZSM-5 molecular sieve) has wide application prospect in the catalytic cracking process due to the advantages of good chemical stability, unique pore channel structure and shape selecting property, flexible and adjustable acidity, strong carbon deposition resistance and the like. The synthesis method of the ZSM-5 molecular sieve mainly comprises a hydrothermal synthesis method, a non-aqueous solvothermal method, a microwave auxiliary synthesis method, a steam auxiliary method and the like. At present, a plurality of documents and patents about ZSM-5 synthesis methods are reported, such as one-step synthesis of HZSM-5 molecular sieve by using macroporous silica gel, aluminum nitrate and n-propylamine as raw materials (Jing Wenjing, zhang Yuxia. One-step green synthesis of HZSM-5 molecular sieve [ J ], shanxi chemical industry, 2024,200 (44): 22-24), the specific surface area of the synthesized molecular sieve is about 92-421m 2/g, although the method has small water consumption and does not need the subsequent processes such as ion exchange, the n-propylamine added in the synthesis process can be decomposed to generate toxic gas which is difficult to treat during roasting, thus being extremely easy to cause environmental pollution; in addition, the invention uses a microwave method, takes silica sol and aluminum sulfate octadecabonate as a silicon source and an aluminum source respectively, can efficiently synthesize the full-crystallization ZSM-5 molecular sieve catalyst containing 100 percent of active components (Wang Darui, sun Hongmin, xue Mingwei, and the like), the microwave method efficiently synthesizes the full-crystallization ZSM-5 molecular sieve catalyst and the catalysis performance [ J ] thereof, chemical progress, 2023,42 (7): 3582-3588), the specific surface area of the synthesized ZSM-5 molecular sieve reaches 419m 2/g, but the method uses a plurality of organic templates such as ammonia water, ethylamine, n-butylamine, and the like, thereby causing the post-treatment process to become complicated and even cause environmental pollution, meanwhile, the equipment required by the microwave technology is relatively expensive, and the microwave technology has strong radiation, which can cause security threat to operators. Therefore, there is a need to develop a new green synthesis route for ZSM-5 molecular sieves that does not use expensive, difficult to post-treat organic templates and can be applied to industrial production. Disclosure of Invention In order to solve the technical problems, the invention aims to provide a Na-type ZSM-5 molecular sieve, a synthesis method thereof and an oil catalytic cracking catalyst. The ZSM-5 molecular sieve with the micropore structure can be synthesized in a green way by using four components only comprising a silicon source, an aluminum source, an alkali source and deionized water, so that the addition of an organic template agent and a seed crystal is avoided, and the catalyst can be used for oil catalytic cracking catalysts. In order to achieve the above purpose, the invention provides a synthesis method of Na-type ZSM-5 molecular sieve, wherein the synthesis method comprises the following steps: (1) Drying and roasting the silicon source and the aluminum source to obtain an activated silicon source and an activated aluminum source; (2) Grinding the activated silicon source, adding the silicon source into the sodium-containing alkaline solution, and carrying out first stirring to obtain molecular sieve gel I; (3) Adding the activated aluminum source into th