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CN-122006795-A - Composite molecular sieve, preparation method and application thereof

CN122006795ACN 122006795 ACN122006795 ACN 122006795ACN-122006795-A

Abstract

The invention relates to a composite molecular sieve, a preparation method and application thereof. The method for manufacturing the composite molecular sieve comprises the steps of 1) providing a first molecular sieve containing a first template agent, and then 2) manufacturing a second molecular sieve in the presence of a second template agent and the first molecular sieve containing the first template agent, so as to obtain the composite molecular sieve, wherein the first template agent and the second template agent can form hydrogen bonds with each other. The composite molecular sieve can improve the selectivity of isomerization reaction, increase the yield of monomethyl branched isomer, and obviously increase the product yield and the product quality.

Inventors

  • SONG ZHAOYANG
  • LI SIJIE
  • LIU QUANJIE
  • XU HUIQING
  • JIA LIMING
  • YANG CHAO
  • LIU SHUYAN

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
20260512
Application Date
20241111

Claims (20)

  1. 1. A method of making a composite molecular sieve comprising the steps of: 1) Providing a first molecular sieve comprising a first template (such as making the first molecular sieve comprising a first template in the presence of the first template), and then, 2) Producing a second molecular sieve in the presence of a second template and the first molecular sieve comprising the first template to obtain the composite molecular sieve, Wherein the first template and the second template are capable of forming hydrogen bonds with each other.
  2. 2. The manufacturing process according to claim 1, wherein the first molecular sieve is an MRE configuration molecular sieve (preferably a ZSM-48 molecular sieve) and the second molecular sieve is a Beta configuration molecular sieve (preferably an all-silica Beta molecular sieve).
  3. 3. The manufacturing method according to claim 2, wherein in step 1) there is also present a silicon source, an aluminum source, an alkali source and water, wherein in step 2) there is also present a silicon source, a fluorine source, an alkali source and water, wherein in step 32) there is present a silicon source, an alkali source, in terms of SiO 2 , in terms of Al 2 O 3 , an alkali source, in terms of OH -1 , in a molar ratio of water to the first template of 1:0.002-0.05:0.01-0.4:10-50:0.01-0.6, preferably 1:0.0025-0.02-0.35:14-45:0.03-0.5, and in a molar ratio of water to the second template of 1:0.2-2.5:0.5:5-40:0.05-0.8, preferably 1:0.3-0.6:0.36:0.3-0.3.
  4. 4. The production process according to claim 1, wherein in step 2) a silicon source is present, the mass ratio of the first molecular sieve comprising the first template to the silicon source (in terms of SiO 2 ) of step 2) is (59-99): 1, preferably (69-99): 1, further preferably (79-99): 1, and/or the average particle size of the first molecular sieve comprising the first template is 85% or more through 60 mesh, preferably 90% or more through 100 mesh, and/or the free water content of the first molecular sieve comprising the first template is not more than 10wt%, preferably not more than 5wt%.
  5. 5. The method of manufacture of claim 1, wherein the first template is capable of being used to synthesize the first molecular sieve, the second template is capable of being used to synthesize the second molecular sieve, and/or the first template is of similar polarity to the second template.
  6. 6. The production method according to claim 2, wherein the first template agent is at least one selected from ethylenediamine, tetramethylammonium chloride, 1, 6-hexamethylenediamine, 1, 8-octanediamine, hexamethylammonium bromide, hexamethylammonium hydroxide, diethylenetriamine, triethyltetramine, tetraethyltetramine, allyltrimethylammonium chloride, preferably allyltrimethylammonium chloride, and the second template agent is at least one selected from tetraethylammonium hydroxide, tetraethylammonium fluoride, triethylamine, tetrapropylammonium hydroxide, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium iodide, preferably tetraethylammonium hydroxide.
  7. 7. The manufacturing method of claim 1, wherein in step 1), the step 1) comprises the steps of: 1-1) mixing a silicon source, other first molecular sieve synthesis sources (such as an aluminum source and an alkali source), a first templating agent, and water to form a first mixture, 1-2) Crystallizing said first mixture to produce said first molecular sieve comprising a first templating agent, 1-3) Isolating the first molecular sieve comprising the first template (preferably, after optional washing and/or optional filtration, drying (in particular spray drying) the first molecular sieve comprising the first template).
  8. 8. The production method according to claim 7, wherein in the step 1-2), the crystallization conditions include a crystallization pressure of normal pressure to system autogenous pressure, presence or absence of seed crystal, a crystallization temperature of 150 ℃ to 200 ℃ (preferably 160 ℃ to 190 ℃) and a crystallization time of 10h to 200h (preferably 16h to 100 h).
  9. 9. The production method according to claim 7, wherein in step 1-3), the drying conditions include a drying temperature of 60 ℃ to 180 ℃, preferably 80 ℃ to 180 ℃ and a drying time of 2h to 20h, preferably 4h to 15h.
  10. 10. The method according to claim 7, wherein in the step 1-3), the spray-drying conditions include a solid content of 25% -65%, an inlet air temperature of 130 ℃ -200 ℃, an outlet air temperature of 50 ℃ -120 ℃ and an inlet air volume of 300m 3 /h-1500m 3 /h.
  11. 11. The method of claim 7, further comprising the step of pulverizing (e.g., grinding) the first molecular sieve containing the first template to an average particle size of 85% or more passing through 60 mesh, preferably 90% or more passing through 100 mesh after the step 1-3).
  12. 12. The method of claim 1, excluding a step capable of removing a portion or all of the first template from the first molecular sieve comprising the first template, or excluding a calcination step from the step 1).
  13. 13. The manufacturing method of claim 1, wherein the step 2) comprises the steps of: 2-1) mixing a silicon source, other second molecular sieve synthesis sources (such as a fluorine source and an alkali source), a second templating agent, and water to form a second mixture, 2-2) Mixing said first molecular sieve comprising a first templating agent with said second mixture to obtain a composite mixture, 2-3) Optionally drying said composite mixture, crystallizing said composite mixture to produce said composite molecular sieve, 2-4) Optionally washing and/or optionally filtering, and drying the composite molecular sieve.
  14. 14. The method of manufacture of claim 13, wherein in step 2-2) the second mixture is finely divided (e.g., sprayed) onto the first molecular sieve comprising the first template.
  15. 15. The manufacturing method of claim 13, wherein in step 2-2) the morphological integrity (in particular the bulk structure or the pore structure) of the first molecular sieve comprising the first template is substantially maintained after the mixing.
  16. 16. The production method according to claim 13, wherein in step 2-3), the composite mixture is dried, the crystallization conditions include a crystallization pressure of from atmospheric pressure to system autogenous pressure, a water vapor concentration of 20% to 70%, preferably 30% to 50%, a crystallization temperature of 120 ℃ to 200 ℃, preferably 140 ℃ to 180 ℃, a crystallization time of 24h to 180h, preferably 30h to 150h, or in step 2-3), the composite mixture is not dried, the crystallization conditions include a crystallization pressure of from atmospheric pressure to system autogenous pressure, a crystallization temperature of 100 ℃ to 200 ℃, preferably 120 ℃ to 180 ℃, a crystallization time of 20h to 150h, preferably 24h to 80h, and/or, in step 2-3), the drying conditions include a drying temperature of 50 ℃ to 160 ℃, preferably 60 ℃ to 120 ℃, a drying time of 0.1h to 20h, preferably 0.5h to 12h.
  17. 17. The production method according to claim 13, wherein in step 2-4), the drying conditions include a drying temperature of 60 ℃ to 180 ℃, preferably 80 ℃ to 150 ℃ and a drying time of 2h to 20h, preferably 4h to 12h.
  18. 18. The method of claim 13, further comprising the step of calcining the composite molecular sieve after the step 2-4), wherein the conditions of the calcining include a calcining temperature of 400 ℃ to 650 ℃ (preferably 450 ℃ to 600 ℃) and a calcining time of 3h to 18h (preferably 4h to 12 h) under an oxygen-containing atmosphere.
  19. 19. The method of manufacture of claim 1, wherein in step 1), the first molecular sieve comprising a first templating agent is not substantially removed after manufacture.
  20. 20. The manufacturing process of claim 1, wherein in step 2), the morphological integrity (particularly the bulk structure or the pore structure) of the first molecular sieve comprising the first template is substantially maintained under the manufacturing conditions of the second molecular sieve.

Description

Composite molecular sieve, preparation method and application thereof Technical Field The invention relates to the technical field of molecular sieves, in particular to a composite molecular sieve, a manufacturing method thereof and application thereof in hydroisomerization. Background The isomerization catalyst is used as the core of alkane isomerization reaction, and usually adopts a bifunctional catalyst with a metal active component and an acid component to respectively realize hydrogenation dehydrogenation and skeleton isomerization reaction steps in the isomerization reaction process. The metal active component is usually a transition metal or a noble metal of group VIII, while the acidic component is mainly a molecular sieve with suitable pore structure and acid properties. The main purpose of the long-chain alkane isomerization reaction is to generate isoparaffin with less branched chains, so that the acidity of an acidic component is not too strong, the pore channel structure also meets the shape selectivity, and the rapid desorption of a product can be promoted, and secondary reaction is avoided, so that the long-chain alkane isomerization catalyst usually adopts a one-dimensional straight pore channel molecular sieve with proper acid strength, such as AEL type molecular sieves, MTT type molecular sieves, TON type molecular sieves, ZSM-48 molecular sieves and the like adopted in U.S. Pat. No. 3, 6294081B 1, U.S. Pat. No. 3, 11220435B1, U.S. Pat. No. 2, 8475648B2 and U.S. Pat. No. 3, 10640389B 2. The pore structure of the molecular sieve can adsorb normal alkane into the pore, and the proper acidity of the molecular sieve enables the normal alkane to carry out isomerization reaction at the orifice, and the molecular sieve pore diameter generally meets the requirement that normal alkane can freely enter and exit and isoparaffin with larger molecular size can not enter, so that the aim of moderate isomerization reaction is fulfilled. However, because the single molecular sieve pore channel structure system has certain limitation in molecular adsorption and diffusion, and the single molecular sieve acid strength also needs to be further regulated and controlled to meet the requirement of long-chain alkane isomerization reaction, the composite molecular sieve has multiple structures and superposition functions, the limitation of the single molecular sieve in molecular adsorption and diffusion can be improved, the pore structures and the acidity of molecular sieves with different characteristics can be efficiently coupled, the synergistic effect is enhanced, and the reaction performance is improved. Chinese patent CN102861606B discloses an EU-1 molecular sieve and Beta molecular sieve double microporous composite molecular sieve, the structure of the composite molecular sieve is that the Beta molecular sieve is tightly wrapped around the EU-1 molecular sieve, the acid strength, the heat and the hydrothermal stability are improved, obvious mesoporous channels are generated, and the double microporous composite molecular sieve can be applied to toluene and trimethylbenzene transalkylation reaction. Chinese patent CN104549462B discloses an alkane isomerization catalyst containing MCM-22/ZSM-22 composite molecular sieve and group VIII noble metal active component, wherein the MCM-22 molecular sieve in the MCM-22/ZSM-22 composite molecular sieve is wrapped around the ZSM-22 molecular sieve, wherein the weight content of MCM-22 is 1% -50%. The catalyst is applied to the isomerization treatment process of the waxy raw material, can reduce the condensation point of the waxy raw material oil, can improve the yield of liquid products, is especially used for the isomerization dewaxing process of lubricating oil fractions, and has the characteristic of high viscosity index of lubricating oil base oil. The inventor of the invention discovers that when a single molecular sieve is used as an isomerization catalyst to catalyze n-alkane to isoparaffin, because the single molecular sieve pore path has weak constraint force and more nonselective acid centers, the single molecular sieve pore path not only generates monomethyl branched isomer in the isomerization process, but also causes excessive isomerization phenomenon, thereby generating more non-ideal components of polymethyl branched isomer. Disclosure of Invention The inventors of the present invention have found that a single molecular sieve isomerisation catalyst surface has a plurality of active sites, but only the active sites at the apertures belong to the selective active sites. After the normal alkane undergoes isomerization reaction at the pore opening of the molecular sieve to generate the monomethyl branched isomer, the monomethyl branched isomer can continue to undergo isomerization reaction to generate the polymethyl branched isomer due to enough reaction space. In addition, when the monomethyl branched isomer diffuses out to contact other non-selective a