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CN-122010139-A - Liquid guiding agent and preparation method thereof, and Na-type ZSM-5 molecular sieve and preparation method thereof

CN122010139ACN 122010139 ACN122010139 ACN 122010139ACN-122010139-A

Abstract

The invention provides a liquid guiding agent and a preparation method thereof, and a Na-type ZSM-5 molecular sieve and a preparation method thereof. The preparation method of the liquid guiding agent comprises the steps of sequentially carrying out first drying and roasting treatment on a first silicon source to obtain a pretreated first silicon source, dissolving a sodium-containing alkali source in water according to the molar ratio of (0.1-4) to (8-20) of SiO 2 :Na 2 O:H 2 O=1, adding the pretreated first silicon source, and carrying out first stirring to obtain the liquid guiding agent. The preparation method is simple, feasible, green and efficient, and the first silicon source, the sodium-containing alkali source and the water are mixed together according to a certain proportion and stirred for a certain time, so that the obtained light yellow gel can play a role in structure guiding by being added into mother liquor of silicate species, the continuous growth of crystals is promoted, and the use of an organic template agent in the production process of molecular sieve materials is avoided.

Inventors

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

Assignees

  • 中国石油天然气股份有限公司

Dates

Publication Date
20260512
Application Date
20241112

Claims (13)

  1. 1. A method of preparing a liquid directing agent, wherein the method comprises: (1) Sequentially carrying out first drying and roasting treatment on the first silicon source to obtain a pretreated first silicon source; (2) According to the molar ratio of (0.1-4) to (8-20) of SiO 2 :Na 2 O:H 2 O=1, dissolving a sodium-containing alkali source in water until the sodium-containing alkali source is completely dissolved, adding a pretreated first silicon source, and obtaining a liquid guiding agent through first stirring; Wherein the molar ratio of the sodium-containing alkali source is calculated as Na 2 O, and the molar ratio of the first silicon source is calculated as SiO 2 .
  2. 2. The method of claim 1, wherein the first silicon source comprises one or a combination of more than two of sodium silicate, silica gel, silica sol, white carbon black, quartz sand.
  3. 3. The method according to claim 2, wherein the first 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 production method according to claim 1, wherein the baking temperature is 500 to 800 ℃ and the baking time is 2 to 6 hours.
  5. 5. The method of claim 1, wherein the molar ratio of the sodium-containing base source to the first silicon source is (0.2-4): 1.
  6. 6. A liquid directing agent prepared by the preparation method of any one of claims 1-5.
  7. 7. The liquid guiding agent according to claim 6, wherein the viscosity of the liquid guiding agent is 45-200 cp.
  8. 8. The preparation method of the Na-type ZSM-5 molecular sieve comprises the following steps: Adding the liquid guiding agent according to claim 6 or 7 into ZSM-5 synthetic gel, performing second stirring aging to obtain aged gel, performing crystallization treatment, cooling, suction filtering and washing, and performing second drying to obtain Na-type ZSM-5 molecular sieve; Wherein the molar ratio of each component in the aged gel is SiO 2 :Al 2 O 3 :Na 2 O:H 2 O= (25-50): 1 (3-15): 800-2000.
  9. 9. The preparation method of claim 8, wherein the ZSM-5 synthetic gel is obtained by mixing and stirring a second silicon source, an aluminum source, a second sodium-containing alkali source and water, wherein the second silicon source is calculated by SiO 2 , the aluminum source is calculated by Al 2 O 3 , and the second 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 first silicon source and the second silicon source added in the aged gel.
  10. 10. The preparation method of claim 9, wherein the second silicon source comprises one or a combination of more than two of tetraethyl orthosilicate, silica gel, silica sol, white carbon black and quartz sand; And/or the aluminum source comprises one or more than two of sodium metaaluminate, aluminum isopropoxide, aluminum sulfate, boehmite and pseudo-boehmite.
  11. 11. The preparation method according to claim 8, wherein the crystallization temperature is 120-170 ℃ and the crystallization time is 48-96 hours.
  12. 12. A Na-type ZSM-5 molecular sieve prepared by the preparation method of any one of claims 8-11.
  13. 13. The Na-type ZSM-5 molecular sieve according to claim 12, wherein the Na-type ZSM-5 molecular sieve has a micropore specific surface area of 310-353m 2 /g and a micropore volume of 0.07-0.14cm 3 /g.

Description

Liquid guiding agent and preparation method thereof, and Na-type ZSM-5 molecular sieve and preparation method thereof Technical Field The invention belongs to the technical field of molecular sieve preparation, and particularly relates to a liquid guiding agent and a preparation method thereof, and a Na-type ZSM-5 molecular sieve and a preparation method thereof. Background The low-carbon olefin such as ethylene and propylene is one of main products of petrochemical industry, and is an important production raw material for producing downstream organic chemical products such as polyethylene, polypropylene, ethylene dichloride, acrylonitrile and the like. The yield and the production technology of the low-carbon olefin are important references for measuring the development level of the petrochemical industry, so that the great development of the low-carbon olefin production technology has great significance. At present, low-carbon olefins such as ethylene and propylene mainly come from main process technologies such as steam cracking (thermal cracking) and catalytic cracking of hydrocarbons. Although the steam cracking technology still occupies the main place, the steam cracking technology has the problems of high CO 2 emission, low target product yield, high energy consumption, high emission and the like at the temperature of 800 ℃ or above, and the catalytic cracking technology relatively reduces the reaction temperature, improves the product yield, realizes adjustable product distribution and becomes the main research direction of the low-carbon olefin production technology. The key of the catalytic cracking process is a catalyst. The solid acid catalyst, such as ZSM-5 molecular sieve, is one of the important catalysts for producing low-carbon olefin by catalytic cracking because of the advantages of unique three-dimensional pore structure, shape selective property, adjustable silicon-aluminum ratio, acidity, good hydrothermal stability and the like. At present, the synthesis of ZSM-5 molecular sieve mainly comprises a template adding system, a template-free system, a crystal seed synthesizing system and the like. Several reports on ZSM-5 molecular sieve synthesis methods are available, such as hydrothermal synthesis methods using tetrapropylammonium hydroxide as a template agent (Yangyang, zhu Peng, lv Xiaohuan, etc.. Synthesis and optimization research of hierarchical pore ZSM-5 nanocrystalline agglomerate molecular sieves [ J ]. Modern chemical industry, 2024,44 (1): 171-176), seed assisted combination pre-crystallization methods (Wang, zhang Peng, yang Fan, etc.. Seed assisted pre-crystallization methods are used for synthesizing nano ZSM-5 molecular sieves and application thereof in propane aromatization reactions [ J ], low carbon chemistry and chemical industry, 2024,49 (2): 67-73,104), solvent-free methods using tetrapropylammonium bromide as a template agent (Wang Fupeng, liu Jia, guo Ziyang, etc.. Solvent-free synthesis of hierarchical pore ZSM-5 molecular sieves and propane aromatization reaction performance research [ J ],2022,19 (51): 23-27). It should be noted that the above invention adds an organic template agent, and the added template agent has two main effects on the synthesis of the molecular sieve, namely (1) template effect and (2) structure guiding effect. Although the molecular sieve synthesized by adding the template agent can obtain higher crystallinity and smaller grain diameter, the organic template agent has the following defects that (1) the production process of the organic template agent is extremely complicated and difficult to realize large-scale industrial production, (2) the production cost of the organic template agent is about 50-70 percent of the synthesis cost of the molecular sieve and is unfavorable for reducing the production cost of the molecular sieve, (3) the hydrothermal synthesis method is used as a classical synthesis method of the molecular sieve, the yield of the classical synthesis method is often not more than 80 percent, a large amount of template agent is still contained in mother liquor which does not finish crystallization, the template agent is not utilized efficiently and causes waste of the production cost, and (4) alkali liquor containing the organic amine template agent has stronger alkalinity and is easy to form ammonia nitrogen wastewater which is difficult to process and has high concentration, thereby being extremely easy to cause environmental pollution. Therefore, there is a need to develop a synthetic route for ZSM-5 molecular sieve which is environment-friendly, environmentally friendly, economical and feasible. The method for synthesizing the ZSM-5 molecular sieve without using an organic template agent or even an organic substance has very important significance. Disclosure of Invention In order to solve the technical problems, the invention aims to provide a liquid guiding agent and a preparation method thereof, and a Na-type ZSM-5 mo