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CN-121988380-A - Preparation method of alkylation catalyst for isomerisation of C-N-C-hexaalkane

CN121988380ACN 121988380 ACN121988380 ACN 121988380ACN-121988380-A

Abstract

The invention discloses a preparation method of a carbon five-carbon hexaalkane isomerization alkylation catalyst, which comprises the following steps of (1) adding a baked MOR molecular sieve into alkali liquor, carrying out ultrasonic oscillation to enable the MOR molecular sieve to be partially dissolved in the alkali liquor to obtain an alkali liquor A with a basic structural unit of a MOR topological structure, (2) adding a nano ZSM-5 molecular sieve and MOR seed crystals into the alkali liquor A, stirring to obtain an alkali liquor B, (3) crystallizing, filtering, washing, drying and roasting the alkali liquor B to obtain a ZSM-5@MOR composite molecular sieve with nano ZSM-5 as a core and MOR as a shell on the outer surface, and (4) carrying out active metal modification on the ZSM-5@MOR composite molecular sieve according to an impregnation method to obtain the catalyst. The preparation method can improve the catalytic stability of the catalyst and the alkylation performance of the C-N-C-hexaalkane.

Inventors

  • LIU FEI
  • BU TINGTING
  • LU QIONG
  • ZHAI LIHUI
  • MA YINGHAI
  • WANG MEI
  • SONG BIN
  • ZHOU JINBO
  • YANG SHUPING
  • WANG TIAN

Assignees

  • 中国石油天然气股份有限公司

Dates

Publication Date
20260508
Application Date
20241101

Claims (10)

  1. 1. A method for preparing a catalyst for isomerizing and alkylating a carbon five-carbon hexaalkane, which is characterized by comprising the following steps: (1) Adding the baked MOR molecular sieve into the alkali liquor, and carrying out ultrasonic oscillation to enable the MOR molecular sieve to be partially dissolved in the alkali liquor so as to obtain an alkali liquor A with a basic structural unit of an MOR topological structure; (2) Adding nano ZSM-5 molecular sieve and MOR seed crystal into the alkali solution A, and stirring to obtain alkali solution B; (3) Crystallizing the alkali liquor B, filtering, washing, drying and roasting to obtain a ZSM-5@MOR composite molecular sieve with nano ZSM-5 as a core and MOR as a shell on the outer surface; (4) And (3) carrying out active metal modification on the ZSM-5@MOR composite molecular sieve according to an impregnation method to obtain the catalyst.
  2. 2. The method of claim 1, wherein the active metal is at least one of zinc, molybdenum, iron, and gallium.
  3. 3. The preparation method according to claim 1, wherein the addition amount of the active metal is 2% -10% of the sum of the mass of the MOR molecular sieve and the mass of the nano ZSM-5 molecular sieve calculated on the basis of the oxide of the active metal.
  4. 4. The preparation method according to claim 1, wherein the alkali liquor comprises at least one of sodium hydroxide solution and potassium hydroxide solution, and the molar concentration of the alkali liquor is 1-5mol/L.
  5. 5. The method according to claim 1, wherein the mass ratio of the lye to the calcined MOR molecular sieve is 10-30:1.
  6. 6. The preparation method according to claim 1, wherein the mass ratio of the nano ZSM-5 molecular sieve to the MOR seed crystal is 0.1-5:1:0.05-0.2.
  7. 7. The method of claim 1, wherein in step (1), the time of the ultrasonic vibration is 4 to 10 hours.
  8. 8. The method according to claim 1, wherein in the step (3), the crystallization temperature is 140 to 180 ℃ and the crystallization time is 12 to 72 hours.
  9. 9. The method according to claim 1, wherein in the step (3), the drying temperature is 80 to 120 ℃ for 6 to 12 hours, and the firing temperature is 450 to 650 ℃ for 3 to 5 hours.
  10. 10. Use of a catalyst obtained by the preparation method according to any one of claims 1 to 9 in the isomerisation alkylation of a carbon five-carbon hexaalkane.

Description

Preparation method of alkylation catalyst for isomerisation of C-N-C-hexaalkane Technical Field The invention belongs to the technical field of petrochemical industry, and relates to a preparation method of an alkylation catalyst for isomerizing carbon five-carbon hexaalkane. Background The carbon five-carbon hexaalkane refers to light components with the distillation range of 30-60 ℃ generated in the crude oil processing process, and mainly comes from the processing processes of atmospheric and vacuum pressure and coking of an oil refining device, hydrocracking, reforming and the like of an aromatic hydrocarbon device. Typically, the C.sub.five-C.sub.six alkanes contain 60 to 99 weight percent (wt%) of paraffins and naphthenes. As the upgrading pace of the quality standard of chinese gasoline is accelerated, the ratio of aromatic hydrocarbon and olefin in the gasoline blending pool needs to be gradually reduced, and the ratio of isoparaffin needs to be increased. The oil product blending process needs a large amount of high-octane oil products, the blending cost is high, and the market competitiveness is poor. Although the naphtha octane number is low, a large amount of normal paraffins in the C-N-hexaalkane can be converted into isoparaffin by adding a small amount of methanol into the light brain raw material and using zeolite molecular sieve materials with proper structures, acidity and metal active centers as catalysts, so that the octane number of the C-N-C-hexaalkane is improved. Therefore, the oil blending agent is used for blending oil products, reduces the consumption of high-octane oil products and improves the market competitiveness. Therefore, the carbon five-carbon hexaalkane isomerization technology is an important means for regulating the quality of gasoline products in modern refineries, and the produced isomerate has the advantages of no sulfur, no aromatic hydrocarbon, no olefin, high octane number, low density and the like, is a high-quality gasoline blending component, and is particularly suitable for producing clean national V gasoline and future national VI gasoline. Existing isomerization processes do not regulate the vapor pressure of light naphtha. In addition, the isomerization catalysts which are industrially applied at present are all acidic carriers loaded with noble metal active components. The catalyst has strict requirements on the contents of sulfur, nitrogen, water and other impurities in the raw materials, and the octane number is improved to a limited extent. The isomerization reaction process requires the presence of hydrogen to avoid coking. Chinese patent CN92101682.4 discloses a super acidic catalyst for hydroisomerization of alkanes, which comprises (1) an oxide or hydroxide of Mn, wherein the Mn content is 0.1-1.0 wt%, and (2) an oxide or hydroxide of Fe, wherein the Fe content is 0.5-2.0 wt%, and (3) Pt or Pd is 0.1-2.0 wt%, and (4) SO 42- is 2.0-16.0 wt%, and (5) a balance of an oxide or hydroxide of Zr. The catalyst is an acidic carrier loaded noble metal active component, and the content of impurities such as sulfur, nitrogen, water and the like in the raw materials is strict. Chinese patent CN03122849.6 discloses a solid acid catalyst for isomerising C4-C7 alkane, which comprises sulfate and group VIII metal supported on a carrier, the carrier is composed of zirconia, alumina and a modifying element, the modifying element is selected from rare earth element or group IIA metal, the modifying element is modified by introducing group IIA metal or rare earth element into zirconia to form a solid solution in zirconia, thereby inhibiting the transition of zirconia from metastable tetragonal phase to stable monoclinic phase, the catalyst can maintain a larger specific surface area at high temperature, the thermal stability of the catalyst is improved, the influence of high temperature on the performance of the catalyst which happens in the use process of the catalyst can be prevented, the cracking activity can be reduced, and the isoparaffin selectivity of the catalyst is improved, but the catalyst is only for the isomerisation of C5, C6 normal alkane, and the alkylation process is not involved. Disclosure of Invention The invention aims at the current technical situation that the prior isomerization process adopts a noble metal catalyst, has high requirements on sulfur and nitrogen and other impurities in raw materials, and has limited octane number improvement range, and provides a preparation method of the catalyst which can increase the alkyl chain of light naphtha, reduce vapor pressure and increase the branching degree of products, namely further improve the octane number. In order to achieve the above object, the present invention provides a method for preparing an alkylation catalyst for isomerization of a carbon five-carbon hexaalkane, the method comprising the steps of: (1) Adding the baked MOR molecular sieve into the alkali liquor, and carrying out ultras