Search

CN-121988381-A - Preparation method of catalyst for increasing octane number of light naphtha

CN121988381ACN 121988381 ACN121988381 ACN 121988381ACN-121988381-A

Abstract

The invention discloses a preparation method of a catalyst for improving octane number of light naphtha, which comprises the following steps of (1) adding a calcined MCM-22 molecular sieve into alkali liquor, carrying out ultrasonic oscillation to enable the calcined MCM-22 molecular sieve to be partially dissolved in the alkali liquor to obtain an alkali liquor A with a basic structural unit of MWW topological structure, (2) adding a nano ZSM-5 molecular sieve and an organic template agent 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@MCM-22 composite molecular sieve with nano ZSM-5 as a core and MCM-22 as a shell on the outer surface, and (4) carrying out transition metal ion modification on the ZSM-5@MCM-22 composite molecular sieve according to an impregnation method to obtain the catalyst. The ZSM-5@MCM-22 composite molecular sieve catalyst prepared by the preparation method disclosed by the invention not only has high catalytic activity in the light naphtha catalytic reaction, but also has excellent isomerization performance and stable catalytic stability.

Inventors

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

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 increasing octane number by using light naphtha, which is characterized by comprising the following steps: (1) Adding the calcined MCM-22 molecular sieve into alkali liquor, and carrying out ultrasonic oscillation to enable the calcined MCM-22 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 MWW topological structure; (2) Adding a nano ZSM-5 molecular sieve and an organic template agent into the alkali solution A, and stirring to obtain an alkali solution B; (3) Crystallizing the alkali liquor B, filtering, washing, drying and roasting to obtain a ZSM-5@MCM-22 composite molecular sieve with nano ZSM-5 as a core and MCM-22 as a shell on the outer surface; (4) And carrying out transition metal ion modification on the ZSM-5@MCM-22 composite molecular sieve according to an impregnation method to obtain the catalyst.
  2. 2. The method according to claim 1, wherein the transition 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 transition metal is 5% -15% of the sum of the mass of the calcined MCM-22 molecular sieve and the nano ZSM-5 molecular sieve calculated on the basis of the oxide of the transition 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 MCM-22 molecular sieve is 15-35:1.
  6. 6. The method according to claim 1, wherein the organic template agent comprises at least one of hexamethyleneimine and trimethyl adamantylammonium hydroxide.
  7. 7. The preparation method of claim 1, wherein the mass ratio of the nano ZSM-5 molecular sieve to the calcined MCM-22 molecular sieve to the organic template is 0.1-5:1:0.05-0.5.
  8. 8. The method of claim 1, wherein in step (1), the time of the ultrasonic vibration is 4 to 10 hours.
  9. 9. 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, the drying temperature is 60 to 110 ℃ and the drying time is 10 to 20 hours, and the baking temperature is 400 to 600 ℃ and the baking time is 3 to 6 hours.
  10. 10. Use of a catalyst obtained by the preparation process according to any one of claims 1 to 9 in a light naphtha catalytic reaction.

Description

Preparation method of catalyst for increasing octane number of light naphtha Technical Field The invention belongs to the technical field of petrochemical industry, and relates to a preparation method of a catalyst for improving octane number by light naphtha. Background With the rapid development of national economy, petroleum is increasingly widely applied in industrial production. Light naphtha is a product obtained by distillation of petroleum, and is currently mainly used for catalytic reforming, cracking, ammonia production, and the like, and according to different distillation degrees, naphtha is classified into light naphtha and heavy naphtha. Light naphtha 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, light naphtha contains 60 to 99 weight percent (wt%) of paraffins and naphthenes, an important raw material for the production of aromatics. However, the light naphtha with the traditional process has lower octane number, larger use amount and higher cost in production, and the octane number can be improved, the use amount and the cost can be reduced through the light naphtha isomerization project. The upgrading steps of the quality standard of Chinese gasoline are accelerated, the proportion of aromatic hydrocarbon and olefin in a gasoline blending pool is required to be gradually reduced, and the proportion of isoparaffin is required 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 light naphtha can be converted into isoparaffins by adding a small amount of methanol to the light naphtha raw material and using zeolite molecular sieve materials with proper structures, acidity and metal active centers as catalysts, so that the light naphtha octane number is improved. Therefore, the oil blending agent is used for blending oil products, and can reduce the consumption of the oil products with high octane number and improve the market competitiveness. Therefore, the light naphtha isomerization technology is an effective means for regulating the quality of gasoline products in modern refineries, and the produced isomerate oil 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. Chinese patent CN201410563642.2 discloses a naphtha conversion catalyst and a preparation method thereof, based on the weight of the catalyst, the MCM-36 molecular sieve is 20% -80%, the zirconia is 1% -20%, the sulfate is 1% -10%, the group IIA metal oxide is 0.1% -5%, the molybdenum oxide is 1% -10%, the phosphorus pentoxide is 0.1% -5%, and the balance is alumina. The preparation method comprises mixing MCM-36 molecular sieve modified by IIA group metal and zirconium with aluminum hydroxide, adding sulfuric acid and/or ammonium sulfate aqueous solution, kneading, extruding, shaping, drying and roasting to obtain catalyst carrier, impregnating active component, drying and roasting to obtain naphtha isomerization catalyst. 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 CN201611152167.5 discloses a naphtha isomerization and desulfurization double-effect catalyst, which comprises, by weight, 25-35 parts of a ZSM-5 molecular sieve with a silica-alumina ratio of 65, 15-25 parts of a ZSM-5 molecular sieve with a silica-alumina ratio of 50, 45-55 parts of a ZSM-5 molecular sieve with a silica-alumina ratio of 90, wherein the molecular sieve is loaded with 2-3 parts of potassium, 0.2-0.3 part of palladium, 1-2 parts of zinc and 3-8 parts of anhydrous aluminum trichloride. However, the catalyst is only used for isomerization and desulfurization of naphtha normal paraffins, 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 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, and a preparation method thereof. Such naphthas include, but are not limited to, straight run naphthas, hydrocracked naphthas, coker naphthas, catalytical