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CN-121974373-A - SAPO-11 molecular sieve, preparation method and application

CN121974373ACN 121974373 ACN121974373 ACN 121974373ACN-121974373-A

Abstract

The invention provides a SAPO-11 molecular sieve, a preparation method and application thereof. The preparation method of the SAPO-11 molecular sieve comprises the steps of enabling first reactant gel comprising a first aluminum source, a first silicon source, a first phosphorus source and a first organic amine template agent to undergo a first crystallization reaction to obtain an intermediate product, conducting acid treatment and/or fluoride ion solution treatment on the intermediate product to obtain a seed crystal, enabling the seed crystal to undergo a second crystallization reaction with second reactant gel comprising a second aluminum source, a second silicon source, a second phosphorus source and a second organic amine template agent to obtain an SAPO-11 molecular sieve precursor, and roasting the SAPO-11 molecular sieve precursor to obtain the SAPO-11 molecular sieve. The preparation method of the SAPO-11 molecular sieve can realize the preparation of the SAPO-11 molecular sieve with small grain size and the regulation and control of the acidity thereof.

Inventors

  • LIU HAIYAN
  • LI LINFENG
  • ZHANG ZISHUO
  • ZHENG TAO
  • HUI TIANLI
  • ZHANG RUI
  • MENG XIANGHAI
  • LIU ZHICHANG

Assignees

  • 中国石油大学(北京)

Dates

Publication Date
20260505
Application Date
20260104

Claims (10)

  1. 1. A method for preparing a SAPO-11 molecular sieve, comprising: Performing a first crystallization reaction on a first reactant gel comprising a first aluminum source, a first silicon source, a first phosphorus source and a first organic amine template to obtain an intermediate product; Carrying out acid treatment and/or fluoride ion solution treatment on the intermediate product to obtain seed crystals; Carrying out a second crystallization reaction on the seed crystal and second reactant gel comprising a second aluminum source, a second silicon source, a second phosphorus source and a second organic amine template agent to obtain a SAPO-11 molecular sieve precursor; And roasting the SAPO-11 molecular sieve precursor to obtain the SAPO-11 molecular sieve.
  2. 2. The method of claim 1, wherein the first reactant gel comprises a molar ratio of the first silicon source, the first phosphorus source, the first aluminum source, and the first organic amine template agent of (0.1-0.4): 1:1:1.5, wherein the first silicon source is calculated as silicon dioxide, the first phosphorus source is calculated as phosphorus oxide, the first aluminum source is calculated as aluminum oxide, and/or, In the first crystallization reaction, the temperature is 160-200 ℃ and the time is 48-120 hours, and/or, The molar ratio of the second silicon source to the second phosphorus source to the second aluminum source to the second organic amine template agent in the second reactant gel is (0.1-0.6) 1:1 (1-2), wherein the second silicon source is calculated by silicon dioxide, the second phosphorus source is calculated by phosphorus oxide, the second aluminum source is calculated by aluminum oxide, and/or, The mass of the seed crystal is 1-5% of the mass of the dry basis in the second reactant gel, the dry basis comprises silicon dioxide, phosphorus oxide and aluminum oxide, and/or, In the second crystallization reaction, the temperature is 160-200 ℃ and the time is 48-120 h, and/or, In the roasting treatment, the temperature is 550-650 ℃ and the time is 3-8 hours.
  3. 3. The method for producing a SAPO-11 molecular sieve according to claim 1 or 2, wherein in the acid treatment, the concentration of the acid solution is 0.2 to 0.3mol/L, the volume of the acid solution is 5 to 10 times the mass of the intermediate product, the temperature of the reaction is 35 ℃, and/or, In the fluoride ion solution treatment, the fluoride ion solution comprises an ammonium fluoride solution, the concentration of the ammonium fluoride solution is 0.1-0.3 mol/L, the volume of the ammonium fluoride solution is 5-10 times of the mass of the intermediate product, and the reaction temperature is 20-25 ℃.
  4. 4. A method of preparing a SAPO-11 molecular sieve according to any one of claims 1 to 3, wherein the second reactant gel is prepared by steps comprising: mixing the second phosphorus source with the second aluminum source to obtain a mixture; and sequentially adding the second silicon source and the second organic amine template agent into the mixture to obtain the second reactant gel.
  5. 5. A SAPO-11 molecular sieve, characterized in that it is prepared using the method for preparing a SAPO-11 molecular sieve according to any one of claims 1 to 4.
  6. 6. The SAPO-11 molecular sieve of claim 5, wherein the SAPO-11 molecular sieve has a grain size of 2.8-4.1 μm; The content of B acid of the SAPO-11 molecular sieve is 23.5-30.9 mu mol/g, and/or, The relative crystallinity of the SAPO-11 molecular sieve is more than or equal to 95 percent, and/or, The specific surface area of the SAPO-11 molecular sieve is 191-211 m 2 /g, the external specific surface area is 89-105 m 2 /g, the micropore volume is 0.06-0.07 cm 3 /g, and the total pore volume is 0.16-0.19 cm 3 /g.
  7. 7. A catalyst comprising the SAPO-11 molecular sieve of claim 5 or 6.
  8. 8. The catalyst of claim 7, further comprising an active component located in at least a portion of the surface and/or at least a portion of the pores of the SAPO-11 molecular sieve; The active component comprises metal elements, wherein the mass percentage of the metal elements is 0.1-1.0%.
  9. 9. A process for producing isoparaffin, comprising: Hydroisomerization of a feed system comprising C10 to C18 linear alkanes using the catalyst of claim 7 or 8 to obtain isoparaffins.
  10. 10. The method for producing isoparaffin according to claim 9, wherein the hydroisomerization reaction is carried out at a temperature of 280 to 320 ℃, a mass space velocity of 1 to 3h -1 , and a pressure of 1 to 2mpa.

Description

SAPO-11 molecular sieve, preparation method and application Technical Field The invention relates to the field of molecular sieves, in particular to a SAPO-11 molecular sieve, a preparation method and application thereof. Background The global aviation transport industry consumes about 20 hundred million barrels of aviation kerosene per year, accounting for 9% of the total petroleum product yield. The raw materials for preparing the aviation kerosene can be divided into oil crops, lignocellulose, sugar and starch biomass, and different types of raw materials can be converted into the aviation kerosene through different technical paths. Regardless of the technical route used for preparing the aviation kerosene, long-chain normal paraffins are finally produced through grease hydrodeoxygenation, and the normal paraffins have higher freezing points and cannot meet the use requirements of the aviation kerosene, so that hydroisomerization reaction is required to be carried out on the normal paraffins, so that the normal paraffins are converted into isoparaffins with lower freezing points. The SAPO-11 molecular sieve has an AEL topological structure (the main pore canal is a ten-membered ring straight pore canal, and the pore size is 0.63 multiplied by 0.39 nm), so that the SAPO-11 molecular sieve has wide application in the petrochemical catalysis field, and particularly has excellent catalytic performance on hydroisomerization reaction of normal alkane. Studies have shown that SAPO-11 molecular sieves with smaller crystallite sizes generally exhibit higher activity and isomerization selectivity in hydroisomerization reactions. In the prior art, the small-grain-size SAPO-11 molecular sieve is mainly prepared by a segmental crystallization method, a heterogeneous seed crystal method and a growth inhibitor method, but the collaborative optimization of the small grain size and the acidity regulation of the SAPO-11 molecular sieve is difficult to realize, the segmental crystallization method has the advantages of complex preparation process, long preparation period and difficulty in stably controlling the acidity of the SAPO-11 molecular sieve, the water supplementing method needs to accurately control the technological parameters in the preparation process, the operation difficulty is high, the acidity of the SAPO-11 molecular sieve cannot be regulated and controlled, the heterogeneous seed crystal method depends on the topological compatibility of the heterogeneous seed crystal and the SAPO-11 molecular sieve, the acidity of the SAPO-11 molecular sieve cannot be regulated and controlled directionally, the residual inhibitor in the SAPO-11 molecular sieve is likely to be caused by the growth inhibitor method, the acidity of the SAPO-11 molecular sieve is likely to be damaged, and the crystalline phase purity of the SAPO-11 molecular sieve is reduced, so that the catalytic performance of the SAPO-11 molecular sieve when the SAPO-11 molecular sieve is applied to a catalyst is reduced. Therefore, there is a need to develop a SAPO-11 molecular sieve that combines a small crystallite size with excellent acidity. Disclosure of Invention The invention provides a preparation method of an SAPO-11 molecular sieve, which can reduce the grain size of the SAPO-11 molecular sieve and improve the acidity of the SAPO-11 molecular sieve. The invention provides an SAPO-11 molecular sieve, which is prepared by the preparation method of the SAPO-11 molecular sieve, and the SAPO-11 molecular sieve has smaller grain size and excellent acidity. The invention provides a catalyst, which comprises the SAPO-11 molecular sieve and has excellent catalytic performance and selectivity. The present invention provides a process for producing isoparaffin, which can improve the yield of isoparaffin by using the above catalyst. The first aspect of the invention provides a method for preparing a SAPO-11 molecular sieve, comprising: Performing a first crystallization reaction on a first reactant gel comprising a first aluminum source, a first silicon source, a first phosphorus source and a first organic amine template to obtain an intermediate product; Carrying out acid treatment and/or fluoride ion solution treatment on the intermediate product to obtain seed crystals; Carrying out a second crystallization reaction on the seed crystal and second reactant gel comprising a second aluminum source, a second silicon source, a second phosphorus source and a second organic amine template agent to obtain a SAPO-11 molecular sieve precursor; And roasting the SAPO-11 molecular sieve precursor to obtain the SAPO-11 molecular sieve. The preparation method of the SAPO-11 molecular sieve, wherein the molar ratio of the first silicon source to the first phosphorus source to the first aluminum source to the first organic amine template agent in the first reactant gel is (0.1-0.4): 1:1:1.5, wherein the first silicon source is calculated as silicon dioxide, the first ph