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CN-118139818-B - ZSM-5 molecular sieve, preparation method and application thereof, hydrotreating catalyst, hydrodewaxing catalyst and application thereof

CN118139818BCN 118139818 BCN118139818 BCN 118139818BCN-118139818-B

Abstract

The invention provides a ZSM-5 molecular sieve, a preparation method and application thereof, a hydrotreating catalyst, a hydrodewaxing catalyst and application thereof. The total pyridine infrared acid amount of the ZSM-5 molecular sieve is 0.03-0.40 mmol/g, the total di-tert-butylpyridine infrared acid amount is 0.002-0.02 mmol/g, the mesoporous volume of the ZSM-5 molecular sieve accounts for 10% -20% of the total pore volume, and/or the mesoporous volume of 2-10 nm accounts for 70% -95% of the total mesoporous volume in the ZSM-5 molecular sieve. The molecular sieve has obvious technical advantages as a carrier or an active component, for example, the hydrodewaxing catalyst prepared by the ZSM-5 molecular sieve can be used for oil treatment and can simultaneously improve the quality and the yield of low-freezing oil.

Inventors

  • HAO WENYUE
  • LIU CHANG
  • GUO JUNHUI
  • CAO JUNFENG
  • WANG FENGLAI

Assignees

  • 中国石油化工股份有限公司
  • 中石化（大连）石油化工研究院有限公司

Dates

Publication Date
20260505
Application Date
20221028
Priority Date
20211029

Claims (20)

  1. 1. A ZSM-5 molecular sieve is characterized in that the total pyridine infrared acid content of the ZSM-5 molecular sieve is 0.03-0.40 mmol/g, the total di-tert-butylpyridine infrared acid content is 0.002-0.02 mmol/g, the mesoporous volume of the ZSM-5 molecular sieve accounts for 10% -20% of the total pore volume, and in the ZSM-5 molecular sieve, the mesoporous volume of 2-10 nm accounts for 70% -95% of the total mesoporous volume.
  2. 2. The molecular sieve of claim 1, wherein, The ZSM-5 molecular sieve has a total pyridine infrared acid content of 0.10-0.20 mmol/g, a total di-tert-butylpyridine infrared acid content of 0.005-0.01 mmol/g, and/or The ratio of the SiO 2 /Al 2 O 3 molar ratio of the outer surface of the ZSM-5 molecular sieve to the total SiO 2 /Al 2 O 3 molar ratio of the ZSM-5 molecular sieve is 2-100:1.
  3. 3. The molecular sieve of claim 2, wherein The ratio of the SiO 2 /Al 2 O 3 molar ratio of the outer surface of the ZSM-5 molecular sieve to the total SiO 2 /Al 2 O 3 molar ratio of the ZSM-5 molecular sieve is 5-30:1.
  4. 4. The molecular sieve according to claim 1 or 2, wherein, The molar ratio of SiO 2 /Al 2 O 3 on the outer surface of the ZSM-5 molecular sieve is 200-1000, and/or The total SiO 2 /Al 2 O 3 molar ratio of the ZSM-5 molecular sieve is 30-100.
  5. 5. The molecular sieve of claim 4, wherein, The molar ratio of SiO 2 /Al 2 O 3 on the outer surface of the ZSM-5 molecular sieve is 500-1000, and/or The total SiO 2 /Al 2 O 3 molar ratio of the ZSM-5 molecular sieve is 40-70.
  6. 6. A process for preparing ZSM-5 molecular sieve according to any one of claims 1 to 5, comprising the steps of: (1) Carrying out hydrothermal treatment on a raw material ZSM-5 molecular sieve; (2) Removing non-framework aluminum in the molecular sieve obtained in the step (1) by adopting a buffer solution, wherein the buffer solution is one or more of oxalic acid-ammonium oxalate solution and acetic acid-ammonium acetate solution, and the pH value range is 4.5-6.5; (3) Impregnating the material obtained in the step (2) with a pore path protecting liquid, wherein the pore path protecting liquid is one or more of isopropylamine solution, tetraethylammonium hydroxide solution and tetrapropylammonium hydroxide solution (4) Adjusting the pH value to 6.5-7.5 by adopting organic acid to treat the material obtained in the step (3); (5) Mixing the material obtained in the step (4) with a dealumination silicon-supplementing reagent to dealuminate and supplement silicon; (6) And (5) filtering, washing, drying and roasting the material obtained in the step (5).
  7. 7. The method according to claim 6, wherein in the step (1), The temperature of the hydrothermal treatment is 400-700 ℃, and/or The hydrothermal treatment time is 0.5-5 h, and/or The pressure of the hydrothermal treatment is 0.05-0.5 mpa.
  8. 8. The method according to claim 7, wherein in the step (1), The temperature of the hydrothermal treatment is 500-600 ℃; The hydrothermal treatment time is 1-2 h, and/or The pressure of the hydrothermal treatment is 0.1-0.3 MPa.
  9. 9. The method of claim 6, wherein, The molar concentration of the acid in the buffer solution is 0.1-1.0 mol/L, and/or The liquid-solid volume ratio of the buffer solution to the molecular sieve obtained in the step (1) is 3:1-10:1.
  10. 10. The method of claim 6 or 7, wherein the process of step (2) comprises: mixing and stirring the molecular sieve obtained in the step (1) with a buffer solution, then carrying out solid-liquid separation, and optionally repeating the operation for 2-4 times.
  11. 11. The method of claim 10, wherein the process of step (2) comprises: the treatment temperature is 40-80 ℃, and the treatment time is 0.5-3 h.
  12. 12. The method according to claim 6 or 7, wherein in step (3), The concentration of the pore canal protection liquid is 0.8-2.0 mol/L.
  13. 13. The method according to claim 6 or 7, wherein in step (3), The impregnation is an isovolumetric impregnation, and/or The dipping treatment temperature is 20-25 ℃.
  14. 14. The method according to claim 6 or 7, wherein in step (4), The organic acid is an organic acid which has a molecular size of 0.55nm to 2nm and can be removed by calcination without damaging the molecular sieve structure.
  15. 15. The method of claim 14, wherein in step (4), The organic acid is one or more of C7-C10 organic acids.
  16. 16. The method of claim 15, wherein in step (4), The organic acid is one or more of 2-methylbenzoic acid, 2-methylbenzenesulfonic acid, 2, 4-dimethylbenzenesulfonic acid, 1,2, 5-trimethylbenzenesulfonic acid and 1,2, 5-trimethylbenzoic acid.
  17. 17. The method of claim 16, wherein in step (4), The organic acid is one or more of 2, 4-dimethylbenzenesulfonic acid and 2, 4-dimethylbenzoic acid.
  18. 18. The method according to claim 6 or 7, wherein the treatment in step (4) comprises mixing the material obtained in step (3) with water.
  19. 19. The method of claim 18, wherein the liquid to solid volume ratio of water to the material obtained in step (3) is 2:1 to 6:1.
  20. 20. The method according to claim 6 or 7, wherein in step (5), The dealumination silicon-supplementing substance of the dealumination silicon-supplementing reagent is one or more of fluosilicic acid, fluorosilicate, silicon halide and silicate ester; And/or The molar concentration of the dealumination silicon-supplementing reagent is 0.3-1.0 mol/L, and/or The mass ratio of the material obtained in the step (4) to the dealumination silicon-supplementing reagent is 1:1-1:5, and/or The mixing temperature is 60-100 ℃.

Description

ZSM-5 molecular sieve, preparation method and application thereof, hydrotreating catalyst, hydrodewaxing catalyst and application thereof Cross Reference to Related Applications The present application claims the benefit of chinese patent application 202111269100.0 filed on 10/29 of 2021, the contents of which are incorporated herein by reference. Technical Field The invention relates to the field of molecular sieves and preparation thereof, in particular to a ZSM-5 molecular sieve, a preparation method and application thereof, a hydrotreating catalyst, a hydrodewaxing catalyst and application thereof. Background In 1972, the Mobile company successfully synthesized the first molecular sieve belonging to the "Pentasil" family, named ZSM-5, using tetraethylammonium hydroxide as a template, the occurrence of which had a milestone significance for the development of molecular sieves. In 1978, kokokotailo et al performed structural analysis on a ZSM-5 molecular sieve, confirmed that the sieve was a three-dimensional double-ten-membered ring pore structure, which was a straight-shaped pore and a sine-shaped pore, respectively, and two sets of ten-membered ring pore were in an orthogonal relationship, wherein the straight-shaped ten-membered ring pore was parallel to the b axis, the pore diameter was 0.53×0.56nm, the sine-shaped ten-membered ring pore was parallel to the a axis, the pore diameter was 0.51×0.55nm, the cell parameters were a=2.017 nm, b=1.996 nm, and c=1.343 nm, respectively, and the pore structure feature provided the shape-selective catalytic performance. The hydrodewaxing reaction utilizes ten-membered ring channels with molecular dynamics sizes of most cyclic hydrocarbons and isoparaffins larger than those of ZSM-5 molecular sieves, and cannot enter the channels to react, so that the selective cracking of chain hydrocarbons with poor low-temperature fluidity is realized. The ZSM-5 molecular sieve raw powder has side reaction due to the existence of pore openings and acidity of the outer surface, and the catalytic performance of the ZSM-5 molecular sieve raw powder is affected. In order to obtain a catalyst with higher para-selectivity and reaction stability, the ZSM-5 molecular sieve must be modified. Wherein silanization of the molecular sieve is a frequently and more effective method of modifying the acidity of the outer surface. The prior silanization can be divided into the following methods of (1) vacuum chemical vapor deposition, (2) flow chemical vapor deposition, (3) liquid phase chemical dipping method, (4) reflux liquid phase deposition and (5) chemical reaction deposition, wherein the aim is mainly to eliminate the acid center of the outer surface by loading amorphous silicon dioxide on the outer surface of a molecular sieve in a deposition mode although the processes are different. However, the conventional silanization method can eliminate the acidity of the outer surface only by repeated and cyclic impregnation, so that a great amount of silicon ester is wasted, the efficiency of the modification process is greatly reduced, and the modified chemical reaction deposition method improves the modification efficiency and the silicon ester utilization rate, but requires special operation, so that the process is complicated, and the problem of blocking the pore channels is inevitably caused. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a ZSM-5 molecular sieve, a preparation method and application thereof, a hydrotreating catalyst, a hydrodewaxing catalyst and application thereof. The ZSM-5 molecular sieve has wide application as a carrier or an active component, for example, the catalyst prepared by the carrier is used for the process of blending partial catalytic diesel oil and/or coked diesel oil in the process of hydrodewaxing processing straight-run diesel oil, and can simultaneously improve the quality and the yield of low-freezing diesel oil. According to the first aspect of the invention, a ZSM-5 molecular sieve is provided, the total pyridine infrared acid amount of the ZSM-5 molecular sieve is 0.03-0.40 mmol/g, the total di-tert-butylpyridine infrared acid amount is 0.002-0.02 mmol/g, the mesoporous volume of the ZSM-5 molecular sieve accounts for 10% -20% of the total pore volume, and/or in the ZSM-5 molecular sieve, the mesoporous volume of 2-10 nm accounts for 70% -95% of the total mesoporous volume. In a second aspect, the present invention provides a method for preparing the ZSM-5 molecular sieve according to the present invention, the method comprising the steps of: (1) Carrying out hydrothermal treatment on a raw material ZSM-5 molecular sieve; (2) Removing non-framework aluminum in the molecular sieve obtained in the step (1); (3) Impregnating the material obtained in the step (2) with a pore canal protection liquid; (4) Treating the material obtained in the step (3) by adopting organic acid; (5) Mixing the material obtained in th