A process for the preparation of a hydrodemetallation catalyst
By preparing a hydrodemetallization catalyst with hexagonal alumina particles and micron-sized spherical pores on its surface, the problem of rapid catalyst deactivation caused by metal impurities in fixed-bed residue hydrotreating technology was solved, achieving efficient removal of Ni and V, which is suitable for heavy oil treatment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- 山西炬华新材料科技有限公司
- Filing Date
- 2023-12-26
- Publication Date
- 2026-06-09
AI Technical Summary
In fixed-bed residue hydrotreating technology, metallic impurities such as Fe, Ca, Ni, and V cause rapid catalyst deactivation, limiting the processing of inferior feedstocks and the operating cycle of the equipment.
Spherical carbon particles were impregnated with an iron-containing solution and mixed with aluminum sol. After drying and calcination, the mixture was subjected to hydrothermal treatment to form an iron-modified alumina support. The support was then impregnated with an active component to prepare a hydrogenation demetallization catalyst. The catalyst surface was covered with hexagonal alumina particles and micron-sized spherical pores to improve the catalyst's metal-carrying capacity and activity.
The catalyst has high efficiency in hydrotreating Ni and V removal, can operate stably for a long time, and is suitable for treating heavy oil with high Ni content, thus extending the operating cycle of the unit.
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Figure CN117797825B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of catalyst preparation technology, specifically relating to a method for preparing a hydrogenation demetallization catalyst. Background Technology
[0002] The efficient and clean conversion of residue oil is crucial for crude oil utilization. Fixed-bed residue hydrotreating technology is an effective means of achieving the lightening of heavy oil and is also the most widely used residue oil processing technology. Currently, the main problem facing fixed-bed residue hydrotreating is that metallic impurities such as Fe, Ca, Ni, and V in the feedstock cause increased pressure drop in the reactor bed and rapid catalyst deactivation, limiting the processing of inferior feedstocks and affecting the unit's operating cycle. Hydrodemetallization (HDM) catalysts are one of the core catalysts in residue hydrotreating technology. Their main function is to remove metallic impurities such as Ni and V from the residue oil feedstock, protecting downstream desulfurization catalysts from poisoning and deactivation by metallic impurities.
[0003] Industrially, the active metals in HDM catalysts are typically Mo, Co, and Ni. Researchers have investigated the effects of different active metal compositions on HDM catalyst performance. Studies have found that for single-component catalysts composed of non-noble metals (such as Mo, Co, Ni, V, Fe, W, Cr, Ti, etc.) and Al₂O₃, Mo exhibits the highest activity in the hydrogenation denickelization reaction; while Mo and Ni catalysts show the highest activity in the hydrogenation devanadiumization reaction. For two-component HDM catalysts, MoNi catalysts show the highest activity in the hydrogenation devanadiumization reaction, followed by MoCo catalysts. In the hydrogenation denickelization reaction, MoCo and MoFe catalysts show the highest activity, while MoNi catalysts exhibit very low activity in both hydrogenation and denickelization. Summary of the Invention
[0004] The purpose of this invention is to provide a method for preparing a hydrodemetallization catalyst. This catalyst has high activity for dehydrogenation, Ni removal, and V removal, while also having a high capacity to accommodate metal impurities. This catalyst is particularly suitable for the hydrotreating of heavy oil with high Ni content.
[0005] The present invention adopts the following technical solution:
[0006] A method for preparing a hydrogenation demetallization catalyst includes the following steps:
[0007] The first step is to impregnate spherical carbon particles with an iron-containing solution and dry them. The dried carbon particles are then mixed evenly with aluminum sol and drop-shaped into balls. The shaped products are then dried and calcined to obtain an iron-modified alumina carrier.
[0008] The second step involves immersing the iron-modified alumina carrier in an organic ammonium solution for hydrothermal treatment I and hydrothermal treatment II. The treated product is then dried and calcined to obtain the treated alumina carrier.
[0009] The third step involves impregnating the alumina support with an active component impregnation solution, followed by drying and calcination to obtain a hydrogenation demetallization catalyst.
[0010] Furthermore, the iron-containing solution mentioned in the first step includes one or a mixture of ferric sulfate, ferric chloride, and ferric nitrate, preferably ferric nitrate, and the iron ion concentration in the solution is 0.1-0.5M, so that the spherical carbon particles are saturated with adsorption during impregnation.
[0011] Furthermore, the spherical carbon particles mentioned in the first step can be commercially available or prepared by existing methods, and the particle size of the spherical carbon particles is 1-8 μm, preferably 1-5 μm.
[0012] Furthermore, the preparation method of the aluminum sol described in the first step is well known in the art. Generally, it involves mixing boehmite with a certain volume of distilled water until homogeneous, and then adding a certain amount of acid solution for acidification while stirring. The boehmite is preferably boehmite with a pore size greater than 12.5 nm, more preferably prepared by the aluminum sulfate-sodium aluminate method. The acid solution includes one or a mixture of several of nitric acid, acetic acid, formic acid, and oxalic acid solutions, preferably a nitric acid solution. The solid content in the sol is 15%-35%.
[0013] Furthermore, the mass ratio of the spherical carbon particles to the aluminum sol mentioned in the first step is 0.3%-0.8%.
[0014] Furthermore, the drying temperature in the first step is 120-180℃, and the drying time is 1-8 hours; the calcination temperature is 450-600℃, and the calcination time is 4-8 hours, and the calcination is carried out in an oxygen atmosphere.
[0015] Furthermore, the organic ammonium solution mentioned in the second step includes one of tetramethylammonium hydroxide, tetraethylaluminum hydroxide, and tetrapropylammonium hydroxide, preferably tetraethylammonium hydroxide.
[0016] Furthermore, the first and second hydrothermal treatments described in the second step are closed hydrothermal treatments carried out in a sealed container, preferably an autoclave. During the first hydrothermal treatment, the organic ammonium solution concentration is 0.8%-2.0%, the solution volume is sufficient to completely submerge the solid material, the hydrothermal treatment temperature is 80-120℃, and the treatment time is 1-4 hours. During the second hydrothermal treatment, the organic ammonium solution concentration is 3.5%-12.5%, the solution volume is sufficient to completely submerge the solid material, the hydrothermal treatment temperature is 140-180℃, and the treatment time is 4-10 hours. The types of organic ammonium used in the first and second hydrothermal treatments can be the same or different, but are preferably the same.
[0017] Furthermore, in the second step, the drying temperature is 100-160℃ and the drying time is 2-8 hours, and the calcination temperature is 600-750℃ and the calcination time is 4-6 hours.
[0018] Furthermore, the active component impregnation solution mentioned in the third step is a molybdenum-nickel-phosphorus solution, in which the molybdenum content, calculated as oxide, is 7.5%-10.5g / 100mL and the nickel content, calculated as oxide, is 1.8-4.3g / 100mL. During impregnation, supersaturated impregnation or equal-volume impregnation can be used, with equal-volume impregnation being preferred.
[0019] Furthermore, in the third step, the drying temperature is 100-160℃ and the drying time is 2-8 hours, and the calcination temperature is 450-550℃ and the calcination time is 4-6 hours.
[0020] The beneficial effects of this invention are as follows:
[0021] 1. This invention provides an alumina support for a hydrodemetallization catalyst, with its surface covered by hexagonal flake-shaped alumina particles, which fill micron-sized spherical pores. The hexagonal flake-shaped alumina particles interweave to form channels of 100-600 μm. These channels are open and have good permeability, facilitating the diffusion of large molecular reactants while improving the anti-clogging ability of the catalyst surface. The channels formed by the hexagonal flake-shaped alumina particles filling the micron-sized spherical pores significantly enhance the catalyst's metal-carrying capacity, resulting in a final catalyst with high activity and stability.
[0022] 2. Spherical carbon particles are impregnated with modified iron. The iron element is oriented and anchored within the micron-sized spherical pores. During hydrothermal treatment of the support, the iron element coordinates the secondary growth process of the alumina particles, improving their interaction with the alumina support. Furthermore, the iron-modified alumina within the micron-sized spherical pores exhibits a synergistic effect during the hydrodemetallization reaction, enhancing both the vanadium-demetallization and nickel-demetallization activities of the catalyst. Because the channels formed by the accumulation of plate-like particles in the micron-sized spherical pores are relatively large and well-open, they can effectively accommodate the removed Ni and V metal impurities, ensuring long-term catalyst operation.
[0023] 3. During the preparation of the alumina support, the support undergoes two hydrothermal treatments to ensure that the resulting hexagonal flake-shaped alumina particles are uniform in size and regular in shape. The flake-shaped particles have high coverage on the support surface and high filling density in the micron-sized spherical pores, effectively improving the mass transfer and diffusion of reactants during the hydrodemetallization reaction. Attached Figure Description
[0024] Figure 1 is a scanning electron microscope image of the alumina support surface prepared in Example 1.
[0025] Figure 2This is a cross-sectional scanning electron microscope image of the alumina carrier prepared in Example 1.
[0026] Figure 3 The image shows a cross-sectional scanning electron microscope image of the alumina support prepared for Comparative Example 1. Detailed Implementation
[0027] The technical solutions and effects of the present invention will be further illustrated below with reference to the embodiments, but the invention is not limited to the following embodiments.
[0028] The microstructure of the sample was characterized using scanning electron microscopy. The specific operation was as follows: accelerating voltage 8KV, accelerating current 10µA, working distance 8mm.
[0029] The micro-region composition of the sample was characterized using a scanning electron microscope-energy dispersive spectroscopy (SEM-EDAX) instrument. The specific procedures were as follows: The SEM was equipped with an EDAX spectrometer, with an accelerating voltage of 25 kV, a probe current of 11 µA, and a working distance of 8 mm. During the measurement, 10 locations were randomly selected in both micrometer-sized spherical pore regions and non-micrometer-sized spherical pore regions. The composition of the corresponding micro-regions was measured, and the average value was taken.
[0030] The preparation method of the carbon particles used in this invention is referenced in the literature: Preparation of starch-based porous carbon materials and their methylene blue adsorption properties [J]. Journal of Dalian University of Technology, 2020, 39(6): 434-438. The carbon particles prepared are spherical with a particle size of 1-5 μm.
[0031] Example 1
[0032] (1) Weigh an appropriate amount of the spherical carbon particles prepared by the above method, impregnate them with 0.35M ferric nitrate solution to saturate the carbon particles with adsorption, and dry them at 120℃ for 4 hours to obtain iron-containing carbon particles; weigh 100g of boehmite (prepared by aluminum sulfate-sodium aluminate method, with a pore size of 13.5nm), add 280g of distilled water, stir evenly, add 16ml of concentrated nitric acid to acidify into a sol; weigh 100g of the above aluminum sol, add 0.65g of iron-containing carbon particles, and stir the materials evenly; drop the mixed sol into an oil-ammonia column device to form drop balls, age the formed material for 3 hours, then dry it at 140℃ for 4 hours, and calcine it at 500℃ in an oxygen atmosphere for 6 hours to obtain iron-modified alumina carrier.
[0033] (2) Take an appropriate amount of the iron-modified alumina carrier prepared in step (1) and add it to the polytetrafluoroethylene liner of the autoclave. Add a 1.2 wt% tetraethylammonium hydroxide solution to completely submerge the alumina carrier. After sealing the autoclave, perform the first hydrothermal treatment at 100℃ for 2.5 hours. After treatment, immerse the material again in a 10 wt% tetraethylammonium hydroxide solution. After sealing the autoclave, perform the second hydrothermal treatment at 155℃ for 7.5 hours. After treatment, dry the material at 120℃ for 6 hours and calcine at 650℃ for 5 hours to obtain the alumina carrier. The scanning electron microscope image of the carrier surface is shown below. Figure 1 Cross-sectional scanning electron microscope image is shown below. Figure 2 .
[0034] (3) Weigh an appropriate amount of the alumina support from step (2) and place it in a spray-dip boiling pot. Impregnate the support with an equal volume of molybdenum-nickel-phosphorus impregnation solution with a molybdenum oxide concentration of 9.3 g / 100 mL and a nickel oxide concentration of 2.6 g / 100 mL. After impregnation, dry the material at 120 °C for 4 hours and calcine at 450 °C for 5 hours to obtain the demetallization catalyst Cat-1. The properties of the catalyst are shown in Table 1.
[0035] Example 2
[0036] Same as Example 1, except that in step (1), the concentration of ferric nitrate solution is 0.25M, and the amount of iron-modified carbon particles added is 0.5g. In step (2), the concentration of organic ammonium solution in the first hydrothermal treatment is 1.5wt%, the hydrothermal treatment temperature is 95℃, and the treatment time is 3.5 hours. In the second hydrothermal treatment, the concentration of organic ammonium solution is 7wt%, the hydrothermal treatment temperature is 165℃, and the treatment time is 6.5 hours, thus obtaining the demetallized catalyst Cat-2. The properties of the catalyst are shown in Table 1.
[0037] Example 3
[0038] Same as Example 1, except that in step (1), the concentration of ferric nitrate solution is 0.15M, and the amount of iron-modified carbon particles added is 0.8g. In step (2), the concentration of organic ammonium solution in the first hydrothermal treatment is 1.9wt%, the hydrothermal treatment temperature is 80℃, and the treatment time is 4 hours. In the second hydrothermal treatment, the concentration of organic ammonium solution is 12wt%, the hydrothermal treatment temperature is 145℃, and the treatment time is 9 hours, thus obtaining the demetallized catalyst Cat-3. The properties of the catalyst are shown in Table 1.
[0039] Example 4
[0040] Same as Example 1, except that in step (1), the concentration of the ferric nitrate solution is 0.45M, and the amount of iron-modified carbon particles added is 0.35g. In step (2), during the first hydrothermal treatment, tetraethylammonium hydroxide is replaced with tetrapropylammonium hydroxide, the solution concentration is 0.9wt%, the hydrothermal treatment temperature is 115℃, and the treatment time is 1.5 hours. During the second hydrothermal treatment, tetraethylammonium hydroxide is replaced with tetrapropylammonium hydroxide, the solution concentration is 4.5wt%, the hydrothermal treatment temperature is 175℃, and the treatment time is 5 hours, thus obtaining the hydrogenation demetallization catalyst Cat-4. The properties of the catalyst are shown in Table 1.
[0041] Comparative Example 1
[0042] Same as Example 1, except that tetraethylammonium hydroxide in step (2) was replaced with ammonia of the same concentration to prepare the comparative hydrogenation demetallization catalyst Cat-5. The properties of the catalyst are shown in Table 1, and the corresponding scanning electron microscope images of the support after treatment are shown in Table 1. Figure 3 .
[0043] Comparative Example 2
[0044] Same as Example 1, except that tetraethylammonium hydroxide in step (2) was replaced with sodium hydroxide of the same concentration to prepare the comparative hydrogenation demetallization catalyst Cat-6. The properties of the catalyst are shown in Table 1.
[0045] Comparative Example 3
[0046] Same as Example 1, except that the hydrothermal treatment was not performed using a high-pressure autoclave, but instead under atmospheric pressure reflux in a condenser reflux apparatus to obtain the comparative hydrogenation demetallization catalyst Cat-7. The catalyst properties are shown in Table 1.
[0047] Table 1 Catalyst Properties
[0048]
[0049] From the data in Table 1 and Figure 1-2 It can be seen that the hydrogenation demetallization catalyst prepared by the method of the present invention has large pores on its surface, which utilizes the diffusion of reactant molecules and contains large pore regions that can accommodate metal impurities inside the catalyst.
[0050] Example 5
[0051] The catalysts prepared in the above examples and comparative examples were respectively loaded into fixed-bed hydrogenation reactors. The feedstocks were processed (see Table 2). The experimental conditions were as follows: reaction temperature 380℃, hydrogen-to-oil volume ratio 750, and liquid hourly space velocity 0.85 h⁻¹. -1 The hydrogen partial pressure was 14.5 MPa, and the impurity removal properties were obtained after 2000 hours of continuous operation. See Table 3 for the results.
[0052] Table 2 Properties of Crude Oil
[0053]
[0054] Table 3 Evaluation results of the catalyst
[0055]
[0056] As can be seen from the data in Tables 2 and 3, the catalyst prepared by the method of this invention exhibits high Ni and V removal activity, making it particularly suitable for processing feedstock oils with high Ni content. Furthermore, the catalyst demonstrates good tolerance to metal impurities, ensuring long-term operation.
Claims
1. A method for preparing a hydrogenation demetallization catalyst, characterized in that: Includes the following steps: The first step is to impregnate spherical carbon particles with an iron-containing solution and dry them. The dried carbon particles are then mixed evenly with aluminum sol and drop-shaped into balls. The shaped products are then dried and calcined to obtain an iron-modified alumina carrier. The drying temperature is 120-180℃, and the drying time is 1-8 hours; the calcination temperature is 450-600℃, and the calcination time is 4-8 hours, and the calcination is carried out in an oxygen atmosphere. The second step involves immersing the iron-modified alumina carrier in an organic ammonium solution for hydrothermal treatment I and hydrothermal treatment II. The treated product is then dried and calcined to obtain the treated alumina carrier. The organic ammonium solution includes tetramethylammonium hydroxide, tetraethylammonium hydroxide, or tetrapropylammonium hydroxide; The first and second hydrothermal treatments are closed hydrothermal treatments carried out in sealed containers. For the first hydrothermal treatment, the organic ammonium solution has a mass concentration of 0.8%-2.0%, the solution volume is sufficient to completely submerge the solid material, the hydrothermal treatment temperature is 80-120℃, and the treatment time is 1-4 hours. For the second hydrothermal treatment, the organic ammonium solution has a mass concentration of 3.5%-12.5%, the solution volume is sufficient to completely submerge the solid material, the hydrothermal treatment temperature is 140-180℃, and the treatment time is 4-10 hours. The type of organic ammonium used in the first and second hydrothermal treatments may be the same or different. The drying temperature is 100-160℃ and the drying time is 2-8 hours; the calcination temperature is 600-750℃ and the calcination time is 4-6 hours. The third step involves impregnating the alumina support with an active component impregnation solution, followed by drying and calcination to obtain a hydrogenation demetallization catalyst. The active component impregnation solution is a molybdenum-nickel-phosphorus solution, in which the molybdenum content (calculated as oxide) is 9.3-10.5 g / 100 mL and the nickel content (calculated as oxide) is 1.8-4.3 g / 100 mL. Supersaturated impregnation or equal-volume impregnation is used during impregnation.
2. The method for preparing a hydrogenation demetallization catalyst according to claim 1, characterized in that: The iron-containing solution mentioned in the first step includes one or a mixture of ferric sulfate, ferric chloride, and ferric nitrate, with an iron ion concentration of 0.1-0.5M, and the spherical carbon particles are saturated with adsorption during impregnation.
3. The method for preparing a hydrogenation demetallization catalyst according to claim 1, characterized in that: The spherical carbon particles mentioned in the first step have a particle size of 1-8 μm.
4. The method for preparing a hydrogenation demetallization catalyst according to claim 1, characterized in that: The aluminum sol described in the first step is prepared by mixing boehmite with distilled water until homogeneous, and then adding an acid solution under stirring for acidification; the boehmite has a probable pore size greater than 12.5 nm; the acid solution includes one or a mixture of several of nitric acid, acetic acid, formic acid, and oxalic acid solutions; and the solid content in the sol is 15%-35%. The mass ratio of the spherical carbon particles to the aluminum sol mentioned in the first step is 0.3%-0.8%.
5. The method for preparing a hydrogenation demetallization catalyst according to claim 1, characterized in that: The drying temperature in the third step is 100-160℃, and the drying time is 2-8 hours. The calcination temperature is 450-550℃, and the calcination time is 4-6 hours.