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CN-117797855-B - Industrial-grade bifunctional catalyst and preparation method and application thereof

CN117797855BCN 117797855 BCN117797855 BCN 117797855BCN-117797855-B

Abstract

The invention relates to an industrial-grade bifunctional catalyst, a preparation method and application thereof. The double-function catalyst mainly comprises a Y-type molecular sieve, an alumina binder and metal of a VIII group, and the preparation process comprises the steps of mixing the Y-type molecular sieve with the alumina binder, adding sesbania powder into the mixture, uniformly mixing the mixture, adding nitric acid into the mixture for acidification, preparing the mixture, forming the mixture, further carrying out pressurized hydrothermal roasting treatment, and then loading the metal and reducing the mixture. The bifunctional catalyst can be used for bridge type tetrahydrodicyclopentadiene isomerization reaction. The preparation method of the catalyst has the advantages of simple process, easy amplification, no pollution, catalyst pore expansion, rich pore volume, high activity and good mechanical strength, is an industrial-grade formed catalyst, and is suitable for industrial application.

Inventors

  • FU CHAOLIN
  • ZHAO JIE
  • XING ENHUI
  • TAO ZHIPING
  • LUO YIBIN
  • YAN RUI

Assignees

  • 中国石油化工股份有限公司
  • 中石化石油化工科学研究院有限公司

Dates

Publication Date
20260505
Application Date
20220923

Claims (11)

  1. 1. A method for isomerizing bridge tetrahydrodicyclopentadiene into hanging tetrahydrodicyclopentadiene comprises isomerizing bridge tetrahydrodicyclopentadiene into hanging tetrahydrodicyclopentadiene in the presence of a bifunctional catalyst, wherein the bifunctional catalyst comprises a Y-type molecular sieve, an alumina binder and metals of group VIII, the content of the Y-type molecular sieve is 60% -90% and the content of the alumina binder is 5% -30% based on 100% of the total mass of the catalyst, the Y-type molecular sieve is at least one selected from HY, USY, REHY, the metals of group VIII are selected from Pt, pd, ru, rh and Ni, when the metals are noble metals selected from Pd, pt, ru and Rh, the metal content is 0.2-0.5%, when the metals are Ni, the metal content is 5-10%, the total pore volume of the bifunctional catalyst is 0.30-0.50cm 3 /g, and the mesoporous volume is 0.15-0.25 cm 3 /g, and the preparation method of the bifunctional catalyst comprises: (1) Mixing the Y-type molecular sieve with an aluminum adhesive and sesbania powder, adding a nitric acid solution, uniformly stirring, extruding and molding to obtain a molded molecular sieve, and drying; (2) Carrying out hydrothermal roasting treatment on the formed molecular sieve for 1-4 hours at 500-600 ℃ under the steam atmosphere of 0.1-0.3 MPa; (3) The water vapor atmosphere is changed into air atmosphere, and the molded molecular sieve is continuously baked to remove Tianfen; (4) Carrying out ammonium exchange treatment on the formed molecular sieve, and reducing the sodium content in the molecular sieve to below 0.2 wt%; (5) And carrying out metal loading, drying and calcining on the formed molecular sieve by utilizing a precursor solution of VIII group metal, and reducing in a reducing atmosphere to obtain the formed bifunctional catalyst.
  2. 2. The method of claim 1, wherein the Y-type molecular sieve is present in an amount of 70% to 80% and the alumina binder is present in an amount of 10% to 30%.
  3. 3. The method of claim 1, wherein the aluminum binder is selected from the group consisting of aluminum sol, pseudo-boehmite, al 2 O 3 .
  4. 4. The process of claim 1 wherein in step (5) the shaped molecular sieve is loaded with metal by an excess volume impregnation process with an impregnation fluid volume excess of 1 to 5 times.
  5. 5. The process of claim 1, wherein the isomerization reaction temperature is 120-180 ℃, the reaction pressure is 0.1-1.0MPa, the mass space velocity is 0.2-5 h -1 , and the hydrogen/liquid volume ratio is 100-3200 Nm 3 /m 3 .
  6. 6. The process according to claim 1, wherein the isomerization reaction temperature is 130-170 ℃, the reaction pressure is 0.2-0.5MPa, the mass space velocity is 0.5-2 h -1 , and the hydrogen/liquid volume ratio is 500-1500Nm 3 /m 3 .
  7. 7. The process according to claim 1, wherein the bridged tetrahydrodicyclopentadiene is mixed with a solvent prior to the reaction to give a mixture having a mass concentration of bridged tetrahydrodicyclopentadiene of from 10 to 80 wt%.
  8. 8. The process according to claim 1, wherein the bridged tetrahydrodicyclopentadiene is mixed with a solvent prior to the reaction to give a mixture having a mass concentration of bridged tetrahydrodicyclopentadiene of from 30 to 60 wt%.
  9. 9. The process according to claim 7 or 8, wherein the solvent is a hydrocarbon or halogenated hydrocarbon solvent having a boiling point of 40-300 ℃.
  10. 10. The method of claim 7 or 8, wherein the solvent is selected from cyclohexane, methylcyclohexane, pendant tetrahydrodicyclopentadiene, or a combination thereof.
  11. 11. The process of claim 1 wherein the bridged tetrahydrodicyclopentadiene and the reaction solvent are premixed uniformly in a feed tank and pumped to the upper end of the fixed bed reactor and passed through the dual function catalyst reaction bed with hydrogen and the reaction product flows out of the lower end of the fixed bed.

Description

Industrial-grade bifunctional catalyst and preparation method and application thereof Technical Field The invention relates to the technical field of hydrocarbon compound isomerization, in particular to a catalyst for preparing hanging-type tetrahydrodicyclopentadiene through bridge-type tetrahydrodicyclopentadiene isomerization, and preparation and application thereof. Background The hanging tetrahydrodicyclopentadiene (Exo-THDCPD) is a polycyclic hydrocarbon compound, the molecular formula is C10H16, the compound has the advantages of high density (0.94 g/cm -3), low freezing point (less than-79 ℃), high volume heat value (39.4 MJ/L), low toxicity and the like, is a liquid fuel with excellent comprehensive performance, can be used alone or as a solvent for compounding with other fuels, and has been widely studied and applied in the field of aviation fuels, for example, JP-9 fuel of army is compounded by hanging tetrahydrodicyclopentadiene, methylcyclohexane and perhydro norbornadiene dimer, and more than 98.5% of JP-10 fuel is hanging tetrahydrodicyclopentadiene. A typical Exo-THDCPD preparation process is a two-step conversion process in which dicyclopentadiene (DCPD) is hydrogenated to prepare bridged tetrahydrodicyclopentadiene (Endo-THDCPD) and then isomerized to Exo-THDCPD. The hydrogenation process is relatively mature and can be completed through a common supported hydrogenation catalyst or Raney nickel catalyst, but the industrial isomerization process still needs to be performed intermittently by taking high-toxicity and high-pollution AlCl 3 as a catalyst, continuous industrial production cannot be realized until now, as described in patent CN 102924216B, the hydroconversion process can realize continuous operation for 2000 hours, but the isomerization conversion process still needs AlCl 3 as a catalyst, so that the Exo-THDCPD yield is low, the cost is high, the pollution in the production process is serious, and the large-scale application of the catalyst is limited. In addition, although some studies have been made on using molecular sieves as isomerization catalysts instead of AlCl 3, such as Y, beta, mordenite, al-MCM-41, al-MCM-48, al-SBA-15, etc. as isomerization catalysts in patent CN 101786936B, only the conversion rate of raw materials and the yield of products have been examined, and the problems of catalyst life and whether the scale-up of continuous production are not involved, and thus the practical application capability has not been achieved. Meanwhile, for the molecular sieve type catalytic Exo-THDCPD isomerization process, the molecular sieve is easy to coke and is a main reason for molecular sieve deactivation, so that the activity stability of the catalyst can be improved by properly treating the molecular sieve to improve the coking resistance of the molecular sieve. In addition, when the molecular sieve catalyst is used in industry, it is required to perform a molding process to ensure that the molecular sieve catalyst has good mechanical properties, and can meet the requirement of long-period operation of the catalyst, but at the same time, the catalytic activity and the catalytic stability of the molecular sieve are required to be maintained to the greatest extent. Disclosure of Invention Aiming at the problem that the catalyst is easy to coke and deactivate in the bridge-type tetrahydrodicyclopentadiene isomerization reaction of the traditional molecular sieve catalyst, the invention provides a bifunctional catalyst suitable for industrial application and a preparation method thereof, and the bifunctional catalyst is applied to the isomerization reaction process. In a first aspect, the present invention provides a bifunctional catalyst, which mainly comprises a Y-type molecular sieve, an alumina binder and a metal of group VIII, wherein the content of the Y-type molecular sieve is 50% -95%, the content of the alumina binder is 5% -50%, and the content of the metal of group VIII is 0.1-20% based on 100% of the total mass of the catalyst. In a second aspect, the present invention provides a method for preparing a bifunctional catalyst comprising: (1) Mixing the Y-type molecular sieve with an aluminum adhesive and optional field coke powder, adding a nitric acid solution, uniformly stirring, extruding and molding to obtain a molded molecular sieve, and drying; (2) Carrying out hydrothermal roasting treatment on the formed molecular sieve at 450-650 ℃ under the steam atmosphere of 0-0.5 MPa; (3) Optionally, when Tianfen is available, switching the water vapor atmosphere to air atmosphere to continuously bake the molded molecular sieve so as to remove Tianfen; (4) Optionally, carrying out ammonium exchange treatment on the formed molecular sieve to reduce the sodium content in the molecular sieve; (5) And carrying out metal loading, drying and calcining on the formed molecular sieve by utilizing a precursor of VIII group metal, and reducing in a reducing atmosphere to obtain t