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CN-121972179-A - Residual oil hydrotreating catalyst and preparation method thereof

CN121972179ACN 121972179 ACN121972179 ACN 121972179ACN-121972179-A

Abstract

The invention discloses a residual oil hydrotreating catalyst and a preparation method thereof, belonging to the technical field of catalytic materials. The preparation method comprises the steps of S1, mixing dolomite, cerium carbonate and zirconia precursors with a silicon dioxide precursor, drying and calcining to obtain a composite carrier, in-situ pore forming by utilizing gas generated by decomposition of the dolomite and the cerium carbonate to form a mesoporous structure, S2, immersing the composite carrier in a modified liquid containing chitosan and mannuronic acid, constructing a crosslinked network coating on the surface of the composite carrier through Schiff base reaction to obtain the modified carrier, S3, immersing the modified carrier in a precursor solution containing a nickel source, a molybdenum source and a sulfur source, and adsorbing, drying and roasting to obtain the catalyst. The invention realizes high dispersion and stable load of active metal components by the synergistic effect of pore structure regulation and surface modification while obtaining a carrier with high porosity and proper pore distribution. The catalyst shows excellent hydrodesulfurization, denitrification and demetallization performances in residuum hydrotreatment.

Inventors

  • XU ZONGKUN
  • XU XIAOTONG
  • WU BO
  • TIAN HAIBO
  • FU ZHIHANG
  • LIAO YAOHUA
  • LI CHAORAN

Assignees

  • 浙江石油化工有限公司

Dates

Publication Date
20260505
Application Date
20260407

Claims (10)

  1. 1. A preparation method of a residuum hydrotreating catalyst is characterized by comprising the following steps: S1, mixing dolomite, cerium carbonate and a zirconia precursor with a silica precursor, and drying and calcining after mixing to obtain a zirconia/silica composite carrier; s2, immersing the zirconia/silica composite carrier in a modified liquid containing chitosan and mannuronic acid, and carrying out ultrasonic vibration and heat treatment to obtain a modified zirconia/silica carrier; s3, dipping the modified zirconia/silica carrier in a precursor solution containing a nickel source, a molybdenum source and a sulfur source, and adsorbing, drying and roasting to obtain the residual oil hydrotreating catalyst.
  2. 2. The method for preparing a residuum hydrotreating catalyst according to claim 1, wherein in step S1, the zirconia precursor is one of zirconium oxychloride or zirconyl nitrate, the silica precursor is one of silica sol or tetraethyl orthosilicate, and the mass ratio of the zirconia precursor to the silica precursor is 10-30:60-85.
  3. 3. The method for preparing a residuum hydrotreating catalyst according to claim 1, wherein in step S1, the dolomite is added in an amount of 5 to 15wt% based on the total mass of the zirconia/silica composite support raw material, and the cerium carbonate is added in an amount of 1 to 5wt% based on the total mass of the zirconia/silica composite support raw material.
  4. 4. The method for producing a residuum hydrotreating catalyst according to claim 1, wherein in step S1, the calcination conditions are that the temperature is raised to 500 to 700 ℃ at a rate of 2 to 5 ℃ per minute in an air atmosphere and the calcination is performed at a constant temperature for 3 to 6 hours.
  5. 5. The preparation method of the residual oil hydrotreating catalyst according to claim 1, wherein in the step S2, the mass volume ratio of the zirconia/silica composite carrier to the modified liquid is 1g:10-15mL, the mass ratio of chitosan to mannuronic acid in the modified liquid is 1-3:1, the total mass concentration of the chitosan and mannuronic acid is 2-6wt%, and the solvent of the modified liquid is acetic acid aqueous solution with the mass fraction of 1-3%.
  6. 6. The method for preparing a catalyst for hydrotreating residuum as claimed in claim 1, wherein in step S2, the ultrasonic vibration condition is constant temperature vibration impregnation at 40-60 ℃ for 2-4 hours, and the heat treatment condition is treatment at 100-150 ℃ for 6-10 hours.
  7. 7. The method for preparing a residuum hydrotreating catalyst according to claim 1, wherein in the step S3, the nickel source is one of nickel nitrate or nickel sulfate, the molybdenum source is ammonium molybdate, the sulfur source is one of thiourea or ammonium sulfide, and the amounts of the nickel source, the molybdenum source and the sulfur source are based on the mass of the modified zirconia/silica support, wherein the loading of nickel is 0.5-1.9mmol/g support, the loading of molybdenum is 0.8-3.2mmol/g support, and the loading of sulfur is 1.9-6.8mmol/g support.
  8. 8. The method for preparing a residuum hydrotreating catalyst according to claim 1, wherein in step S3, the solvent of the precursor solution is a mixed solution of deionized water and ethanol in a volume ratio of 1:0.8-3, and the mass volume ratio of the modified zirconia/silica carrier to the precursor solution is 1g:8-12mL.
  9. 9. The preparation method of the residual oil hydrotreating catalyst according to claim 1, wherein in the step S3, the soaking condition is that the temperature is 50-60 ℃ and the oscillation frequency is 100-300r/min, the soaking time is 8-12h, and the roasting condition is that under the protection of inert gas, the temperature is firstly increased to 100-300 ℃ for 1h at 1-5 ℃ per min, then is increased to 400-450 ℃ for 1-3h, and finally is increased to 500-550 ℃ for 3-4h.
  10. 10. A residuum hydrotreating catalyst, characterized in that it is obtainable by the preparation process according to any one of claims 1 to 9.

Description

Residual oil hydrotreating catalyst and preparation method thereof Technical Field The invention belongs to the technical field of catalytic materials, and particularly relates to a residual oil hydrotreating catalyst and a preparation method thereof. Background The residuum hydrogenation technology is one of the core processes for realizing clean and efficient conversion of heavy residuum. The technology can effectively remove sulfur, nitrogen, metal and other impurities in residual oil under higher hydrogen partial pressure through catalysis, and simultaneously saturate part of aromatic hydrocarbon and crack macromolecules, thereby producing cleaner and higher-value light distillate oil. Compared with the traditional coking process, the residual oil hydrogenation technology has the characteristics of high liquid product yield, good product quality, good environmental benefit and the like. However, residuum hydrogenation processes face extremely complex reaction environments. The reactant is a complex mixture containing a large amount of asphaltene, colloid, polycyclic aromatic hydrocarbon and other macromolecules, and the reaction process is the result of the comprehensive actions of a plurality of steps such as diffusion mass transfer of reactant molecules in a catalyst pore channel, adsorption on an active center, surface chemical reaction, product desorption and the like. Wherein, the performance of the catalyst is a core factor for determining the technical and economic indexes of the whole process. The excellent performance residuum hydrogenation catalyst needs to meet two seemingly contradictory but synergistic optimization key structural requirements, namely, one needs to have a sufficiently large pore diameter and a proper pore diameter distribution. The method is used for ensuring that large molecules such as asphaltene in the residual oil with huge volume can smoothly diffuse into the catalyst particles and contact the active center of the inner surface, so that the catalyst is prevented from being deactivated in advance caused by too fast coking and blocking of the orifice, and the whole volume of the catalyst is fully utilized. Secondly, it is necessary to possess a sufficiently high specific surface area and a rich surface active site. This is to support the hydrogenation-active metal component in a high density, highly dispersed manner and to form a suitably sized, fully exposed active phase, thereby providing sufficient intrinsic catalytic activity. In the traditional catalyst preparation, the pore size is often increased at the expense of specific surface area, but the pursuit of high specific surface area usually leads to smaller pore size, and the intrinsic contradiction between the pore structure and the active site severely restricts the further improvement of the comprehensive performance of the catalyst. In addition, how to realize high dispersion and effective stabilization of active metal components on macroporous carriers and prevent sintering aggregation during preparation or use is also a technical difficulty. The conventional impregnation method is easy to cause uneven distribution and local aggregation of active metals due to factors such as uneven surface properties of a carrier or surface tension of impregnation liquid, and the generation efficiency and final catalytic performance of an active phase are affected. Therefore, it is necessary to develop a novel preparation method capable of precisely cooperatively controlling the macroscopic pore structure of the catalyst to optimize mass transfer and synchronously realizing high dispersion and stable loading of active components on a microscopic scale. Disclosure of Invention Aiming at the situation, in order to overcome the defects in the prior art, the invention prepares the residual oil hydrotreating catalyst with high porosity and proper pore distribution, and the catalyst can show excellent hydrodesulfurization, denitrification and demetallization performances in the residual oil hydrotreating process. In order to achieve the aim, the invention provides a preparation method of a residual oil hydrotreating catalyst, which comprises the following steps: S1, mixing dolomite, cerium carbonate and a zirconia precursor with a silica precursor, and drying and calcining after mixing to obtain a zirconia/silica composite carrier; s2, immersing the zirconia/silica composite carrier in a modified liquid containing chitosan and mannuronic acid, and carrying out ultrasonic vibration and heat treatment to obtain a modified zirconia/silica carrier; s3, dipping the modified zirconia/silica carrier in a precursor solution containing a nickel source, a molybdenum source and a sulfur source, and adsorbing, drying and roasting to obtain the residual oil hydrotreating catalyst. Further, in step S1, the zirconia precursor is one of zirconium oxychloride or zirconium oxynitrate, the silica precursor is one of silica sol or ethyl orthosilicate,