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CN-121988371-A - Catalyst for improving octane number by isomerizing light naphtha and preparation method thereof

CN121988371ACN 121988371 ACN121988371 ACN 121988371ACN-121988371-A

Abstract

The invention discloses a catalyst for improving octane number by light naphtha isomerization and a preparation method thereof, wherein the catalyst comprises 40-70wt% of carrier, 5-15wt% of dispersing agent, 15-25wt% of pore-forming agent and 8-20wt% of transition metal, wherein the transition metal is calculated by oxide thereof. The ZSM-5@ZrO 2 composite molecular sieve catalyst has the characteristics of good accessibility of catalytic active centers, high catalytic activity, good stability and the like, and the diffusion resistance is reduced and the diffusion of reactants and products is accelerated due to the mesopores of the shell.

Inventors

  • WANG MEI
  • YANG SHUPING
  • LIU FEI
  • LU QIONG
  • WANG YANFEI
  • MA YINGHAI
  • SUN SHILIN
  • XIAO HAN
  • WANG TIAN
  • BU TINGTING

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 catalyst for improving octane number for light naphtha isomerization is characterized by comprising 40-70wt% of a carrier, 5-15wt% of a dispersing agent, 15-25wt% of a pore-forming agent and 8-20wt% of a transition metal, wherein the transition metal is calculated as oxide thereof.
  2. 2. The catalyst of claim 1, wherein the carrier is compounded from a ZSM-5 type molecular sieve and zirconia.
  3. 3. The catalyst of claim 1, wherein the dispersant is at least one of polyethylene glycol type polyol, sodium oleate, carboxylate, sulfate salt, sulfonate salt.
  4. 4. The catalyst of claim 1, wherein the pore-forming agent is at least one of activated carbon, sesbania powder, and starch.
  5. 5. The catalyst of claim 1, wherein the transition metal is at least one of zinc, molybdenum, iron, gallium.
  6. 6. A process for preparing a catalyst for the isomerization of light naphtha to increase octane number comprising the steps of: (1) Carbonizing the nano ZSM-5 molecular sieve of the unfired template agent, namely placing the unfired nano ZSM-5 in a muffle furnace, and treating the ZSM-5 in an air/oxygen atmosphere; (2) Fully pulverizing the pretreated nano ZSM-5 molecular sieve, and drying; (3) Preparing a zirconium salt aqueous solution, adding a fully powdered nano ZSM-5 molecular sieve, a dispersing agent and a pore-forming agent into the zirconium salt aqueous solution to prepare a solution A, and stirring; (4) Slowly dropwise adding ammonia water into the solution A, regulating the pH value, stirring, evaporating water to obtain a solid, drying and roasting to obtain the ZSM-5@ZrO 2 composite molecular sieve; (5) And carrying out transition metal ion modification on the ZSM-5@ZrO 2 composite molecular sieve by an impregnation method to obtain a transition metal modified ZSM-5@ZrO 2 composite molecular sieve catalyst.
  7. 7. The method according to claim 6, wherein the zirconium salt is one of zirconium nitrate, zirconium citrate, zirconium sulfate, zirconium carbonate, zirconium phosphate or zirconium hydroxide.
  8. 8. The preparation method according to claim 6, wherein the mass ratio of zirconium salt to ZrO 2 , the nano ZSM-5 molecular sieve, zrO 2 , the dispersing agent, the pore-forming agent and H 2 O is 1:0.05-0.3:0.1-0.5:0.05-0.24:3-1.
  9. 9. The method according to claim 6, wherein in the step (1), the treatment is performed at a temperature of 150 to 350 ℃ for a time of 10min to 10h; In the step (3), the temperature of stirring is 40-80 ℃ and the time is 2-4 hours; in the step (4), the pH value is regulated to 9-10, and the stirring time is 2-4 hours.
  10. 10. Use of a catalyst according to any one of claims 1 to 5 or a catalyst obtainable by a process according to any one of claims 6 to 9 in a light naphtha catalytic reaction.

Description

Catalyst for improving octane number by isomerizing light naphtha and preparation method thereof Technical Field The invention belongs to the technical field of petrochemical industry, and relates to a catalyst for improving octane number by isomerizing light naphtha and a preparation method thereof. Background The light naphtha in future refining industry can face the problem of going out due to the influence of both international and domestic aspects, the resistance is that low-cost ethylene products in the middle east and North America can impact domestic naphtha ethylene production enterprises, the driving force is that the upgrading steps of the quality standard of Chinese gasoline are accelerated along with the national importance of environmental protection, the proportion of aromatic hydrocarbon and olefin in a gasoline blending pool is gradually reduced, and the proportion of isoparaffin is increased. The national automotive gasoline quality standard is increasingly strict in the restrictions and regulations on indexes such as sulfur content, olefin content, saturated vapor pressure and the like in gasoline, and the production of clean gasoline requires blending components with low sulfur, low olefin and higher octane number. The light naphtha mainly comes from a continuous reforming device raw material pretreatment unit, an aromatic hydrocarbon extraction unit, hydrocracking and other devices, and the main components are C5 and C6 alkanes, mainly straight-chain alkanes, and have lower octane number. At present mainly as ethylene cracking and raw materials of hydrogen production and other devices. With the optimization of plant feed structures using natural gas to produce hydrogen and fully utilizing less than C4 alkanes as ethylene cracking feedstock, refineries will have a surplus of light naphtha to be further processed. The light naphtha isomerate is sulfur-free, olefin-free and aromatic-free, and the octane number (RON) of the light naphtha can be improved by 10-20 by adopting different light naphtha isomerate technologies and processing flows. Light naphtha isomerization technology is a mature process and is widely used abroad. Domestic light naphtha isomerization technical research also has a good foundation and has industrial application devices. With the optimization of the feed structure of the ethylene cracking and hydrogen production units, more light naphtha is provided for the light naphtha isomerization unit as the feed. The isomerization of the light naphtha not only can solve the product outlet problem of the light naphtha, but also has positive effects on the adjustment of the industrial structure of an oil refinery, the optimization of the production flow and the upgrading of the gasoline quality. The catalyst for improving the octane number is prepared by compositing the molecular sieve and the oxide, so that the product is used for oil blending, the consumption of high-octane oil can be reduced, and the market competitiveness is improved. Therefore, the light naphtha isomerization technology is an important technical means for regulating the quality of gasoline products in modern refineries. By adding a small amount of methanol into the light naphtha raw material and using zeolite molecular sieve materials with proper structures, acidity and metal active centers as catalysts, a large amount of normal paraffins in the light naphtha can be converted into isoparaffins, so that the octane number of the light naphtha is improved. One way to reduce the linear paraffin content of hydrocarbons is by isomerizing paraffins from predominantly linear paraffins to predominantly branched paraffins. Chinese patent CN201810315439.1 discloses a method for converting naphtha into high octane gasoline and aromatic hydrocarbon, separating C5-C6 normal paraffins in naphtha, isomerizing the normal paraffins, and aromatizing the obtained isomerized product under the action of Pt/KL zeolite catalyst, so that normal paraffins and monomethyl paraffins in the isomerized equilibrium product are converted into aromatic hydrocarbon. The catalyst adopted by the method 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 No. cn201910314572.X discloses a method for hydroisomerization conversion of naphtha, which comprises contacting a naphtha raw material with a hydroisomerization catalyst to perform hydroisomerization reaction, and separating a hydroisomerization stream obtained after the hydroisomerization reaction to obtain isomerized gasoline, wherein the hydroisomerization catalyst contains an active component and a carrier, the active component is a mixture of an active metal element a and an active metal element B in a weight ratio of (1-6): 1 as oxides, and the active metal element a contains tungsten and/or molybdenum, and the active metal element B contains nickel and/or coba