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CN-121990584-A - Method for short-process ultrastable modification of Y-type molecular sieve

CN121990584ACN 121990584 ACN121990584 ACN 121990584ACN-121990584-A

Abstract

The invention discloses a method for modifying a Y-type molecular sieve in a short process in an ultra-stable way. The method comprises the steps of preparing a first slurry by using a working solution after the NaY molecular sieve is washed by water, adding a rare earth salt solution into the first slurry, adding inorganic acid to adjust the pH value, performing ion exchange to obtain a second slurry, washing, filtering, flash drying, roasting at 500 ℃ for 2.5 hours to obtain a first powder, sending the first powder and SiCl 4 gas into a reactor, keeping the reaction materials for 10 minutes, adding water into a negative pressure beating tank, beating, controlling the pH value to be 2.5-3.5, and obtaining a third slurry, washing, filtering and beating the third slurry by adding water to obtain the ultrastable molecular sieve slurry. The super stable molecular sieve prepared by the invention has 8-15% of rare earth oxide content, 24.25-24.60 Emi of unit cell constant and 600-650 m 2 /g of specific surface, and realizes flexible adjustment of rare earth content.

Inventors

  • SHI MAOCAI
  • WEI ZHAOCHENG
  • LI JUN
  • ZHAO LIANG
  • TANG YULONG
  • WU CHAO
  • PEI YONGZHI
  • CAO XIAOCHENG
  • CHEN JUN
  • WU ZHEN
  • ZHANG GUOXIN
  • ZHANG JIHUA
  • LIU YUHANG
  • LI NING
  • ZHANG HAIRUI
  • YANG DEHENG

Assignees

  • 中国石油天然气股份有限公司

Dates

Publication Date
20260508
Application Date
20241108

Claims (10)

  1. 1. A preparation method of an ultra-stable molecular sieve is characterized by comprising the following steps: The preparation method comprises the steps of carrying out rare earth ion exchange, washing with water, filtering, drying, roasting, carrying out gas-phase ultrastable modification with gas containing halogen silane as a reaction material through dealumination and silicon supplementing reaction, and carrying out acid pulping on the molecular sieve material obtained by the reaction under the negative pressure condition to obtain the ultrastable molecular sieve finished product.
  2. 2. The method for preparing a super stable molecular sieve according to claim 1, wherein the molecular sieve material is NaY molecular sieve with a relative crystallinity of not less than 83% and a silicon-aluminum ratio of not less than 4.80, and the pH value of the NaY molecular sieve is not more than 11.
  3. 3. The method for preparing a super stable molecular sieve according to claim 1, wherein the rare earth oxide content of the NaY molecular sieve subjected to rare earth ion exchange is 8% -16%.
  4. 4. The method for preparing a ultrastable molecular sieve according to claim 1, wherein the drying condition comprises evaporating water under reduced pressure at 100-180deg.C.
  5. 5. The method for preparing the ultra-stable molecular sieve according to claim 1, wherein the gas does not contain carrier gas, and the amount of the powder obtained by roasting in the dealumination and silicon supplementing reaction is controlled to be 200-500 kg/h.
  6. 6. The preparation method of the ultra-stable molecular sieve according to claim 1, wherein the conditions of the dealumination and silicon supplementing reaction comprise the reaction temperature of 280-400 ℃ and the reaction time of 5-15 minutes, and the powder obtained by roasting is in gas-solid phase contact with SiCl 4 gas according to the dry basis mass ratio of 1:0.15-0.6.
  7. 7. The method for preparing a super stable molecular sieve according to claim 1, wherein the acidic pulping specifically comprises the steps of pulping the molecular sieve material at 0-200 Pa and controlling the pH to be 2-5.
  8. 8. The method for preparing the ultrastable molecular sieve according to claim 1, wherein the method comprises the following steps: Step 1, washing a NaY molecular sieve, and preparing the NaY molecular sieve or NaY molecular sieve slurry into a first slurry with the solid content of 100-450 g/L by using water or a recovered rare earth ion exchange working solution after washing; step 2, mixing the first slurry with rare earth salt solution according to the weight ratio of NaY dry basis to rare earth oxide of 1:0.01-0.2, regulating pH to 3.5-4.5, and then carrying out ion exchange at 10-75 ℃ to obtain second slurry; Step 3, filtering the second slurry to obtain a filter cake, washing the filter cake with water, performing suction filtration and flash drying, and roasting at 450-600 ℃ for 2-3.5 hours to obtain powder; Transferring the powder obtained in the step 3 into a reactor according to the speed of 250kg/h-400kg/h, reacting with SiCl 4 gas introduced into the reactor to form a reacted material, and keeping the powder in the reactor for 8-12 minutes; And 5, filtering the third slurry to obtain a filter cake, washing the filter cake with water, and then carrying out suction filtration and pulping by adding water to obtain the ultra-stable molecular sieve slurry.
  9. 9. A ultrastable molecular sieve produced by the process for producing a ultrastable molecular sieve according to any one of claims 1 to 8.
  10. 10. The ultrastable molecular sieve according to claim 9, wherein the rare earth oxide content of the ultrastable molecular sieve is 8% -15%, the unit cell constant is 24.25-24.60 emm, and the specific surface is 600-650 m 2 /g.

Description

Method for short-process ultrastable modification of Y-type molecular sieve Technical Field The invention belongs to the technical field of molecular sieve preparation, relates to a Y-type molecular sieve gas phase ultrastable modification technology, and in particular relates to an industrial preparation method of a ultrastable molecular sieve. Background The improvement of the performance of the catalytic cracking catalyst mainly depends on the improvement of the performance of the active component ultrastable molecular sieve. In recent years, research on ultra-stable modification of the Y-type molecular sieve is also paid attention to, three methods of a hydrothermal method, a liquid-phase fluorine ammonium salt method and a gas-phase chemical method are mainly adopted in the existing method for ultra-stable modification of the Y-type molecular sieve, the hydrothermal method and the liquid-phase fluorine ammonium salt method have inherent defects and disadvantages, the two methods of ultra-stable modification of the molecular sieve face the problem of high ammonia nitrogen wastewater treatment in production, the production process is long, the energy consumption is high, the cost reduction and the synergy of catalyst production enterprises are severely restricted, and great burden is brought to the clean and environment-friendly production of enterprises. The liquid-phase fluorine ammonium salt method also has the problem that the production device discharges production wastewater containing fluoride to cause environmental pollution, and the residual fluoride in the production process affects the stability of the molecular sieve. The whole production process of gas phase ultra-stabilization modification does not produce wastewater containing high ammonia nitrogen and fluoride, and the obtained modified molecular sieve is an ideal residual oil cracking catalyst and an active component of an octane number-improving catalyst while meeting the requirements of clean and environment-friendly production. The Y-type molecular sieve gas-phase superstable modification can adopt a reaction principle that NaReY molecular sieve is subjected to isomorphous substitution to finish dealumination and silicon supplementation at one time, and can also effectively avoid framework structure damage caused by lattice collapse of NaReY molecular sieve in the dealumination process through second-level reaction in the substitution process, thereby influencing the activity of the molecular sieve. In the prior industrial application, in order to ensure the gas-phase ultrastable modification effect, for example, to ensure the high silicon content of the molecular sieve, the condition of excessive use of silicon tetrachloride exists, so that high-energy consumption environment-friendly treatment is required to ensure the production continuity. For this reason, CN102451655A proposes a molecular sieve industrial continuous production device based on gas-phase superstable modification, which improves the production efficiency by adopting a riser reaction technology of connecting a inclined tube and a straight tube in series, Compared with industrial REY, the ultrastable modified Y-type molecular sieve has the advantages that the silicon tetrachloride consumption is reduced, the problem that the rare earth oxide content (namely the rare earth mass percentage calculated by RE 2O3) is lower, the use effect of the catalyst is affected, the reactor and the gas-solid separator in CN103769193A can be operated by adopting micro negative pressure, the carrier gas can be not used any more by adopting a conveying device reactor (for example, the molecular sieve moves in a tubular reactor by adopting the mechanical conveying effect of a screw conveyor and the like), and the reaction rate can be improved, The vertical gas-phase ultrastable reactor disclosed in CN114100531A enables the dry molecular sieve to form a fully mixed flow state and a partial fully mixed flow state with countercurrent gas-phase silicon tetrachloride (namely SiC1 4 gas) after passing through the distributor, thereby effectively ensuring gas-solid contact, generating transient reaction in extremely short contact time, avoiding overlong contact time and excessive SiC1 4 molecules carried by the reacted molecular sieve, and ensuring that the catalyst has high purity and high purity, and is suitable for being used for preparing catalyst 5.5, 8.0, etc.), the gas-phase ultrastable Y-type molecular sieve with higher relative crystallinity is obtained, but for the reaction process using NaY and NaReY (namely NaY exchanged by rare earth ions) as molecular sieve raw materials, the change of relative crystallinity before and after the reaction can not accurately reflect the quality of the product, the reaction time is not easy to control, the degassing of the reacted materials is also needed, the parallel-flow continuous automatic operation based on a vertical reactor in CN106517