Hydrodemetallization catalyst and preparation method thereof

Abstract

The invention provides a hydrodemetallization catalyst and a preparation method thereof, and is suitable for the field of catalyst preparation. The preparation method comprises the following steps: preparing an active metal modified amorphous aluminum oxide compound; preparing metal modified unit cell distortion pseudo-boehmite; uniformly mixing pseudo-boehmite C, metal modified unit cell distorted pseudo-boehmite and sesbania powder, adding a peptizing agent, kneading and forming, and performing third drying and third roasting to obtain an alumina carrier; carrying out second dipping, fourth drying and fourth roasting on the alumina carrier by the solution B containing the active metal component to obtain a catalyst precursor; and adding a second urea solution into the catalyst precursor, carrying out third hydrothermal treatment, filtering, washing, carrying out fifth drying, and carrying out fifth roasting to obtain the hydrodemetallization catalyst, the catalyst has the beneficial effects that the active metal distribution of the catalyst is matched with the pore channel structure, the metal and carbon deposition resistance is high, the operation period is long, flaky particles on the outer surface are stacked into open pore channels, and the activity and stability of the catalyst are improved.

Description

Technical Field

[0001] The present application relates to the field of catalyst preparation, and in particular to a hydrodemetallization catalyst and a preparation method thereof. Background Art

[0002] In recent years, with the increasing stringency of heavy crude oil resources, the use of hydrogenation technology to convert heavy oil, including residual oil, into high-quality fuel oil and chemical products has helped to improve crude oil utilization, reduce environmental pollution, increase light oil yield and improve product quality. However, the hydrodemetallization catalysts used for heavy oil, especially the hydrodemetallization catalysts used for vacuum residue with a high metal content, are prone to rapid decline in catalyst activity or even deactivation due to the deposition of metal impurities such as nickel and vanadium. Activated alumina, as a good hydrogenation catalyst support material, is widely used in the oil refining industry. Catalysts with larger pore volumes and larger pore diameters have strong metal and carbon tolerances, which can slow down the decline in catalyst activity and extend the catalyst's operating cycle. However, the alumina commonly used to prepare hydrotreating catalysts and commercially available alumina have relatively small pore diameters and cannot meet the needs of preparing heavy oil, residual oil hydrodemetallization and / or heavy oil hydrodesulfurization catalysts.

[0003] Conventional methods for preparing hydrodemetallization catalysts involve first preparing an alumina support, then loading the active metal components onto the support surface, followed by drying and calcination. These hydrodemetallization catalysts, prepared using this method, exhibit strong interactions between the active components and the support, resulting in insufficient surface defects on the catalyst, hindering the full development of the catalyst's activity. Summary of the Invention

[0004] In order to solve one of the above technical deficiencies, the present application provides a hydrodemetallization catalyst and a preparation method thereof.

[0005] According to a first aspect of the present application, a method for preparing a hydrodemetallization catalyst is provided, comprising: Preparation of active metal modified amorphous aluminum oxide compounds; Amorphous aluminum oxide is prepared into metal-modified unit cell distorted pseudo-boehmite; Pseudoboehmite C, metal-modified unit cell distorted pseudoboehmite and sesbania powder are weighed and mixed uniformly, a peptizing agent is added, kneaded and formed, and then subjected to a third drying and a third calcination to prepare an alumina support; Weighing an alumina support, performing a second impregnation on the alumina support using solution B containing an active metal component in a saturated impregnation manner, and then performing a fourth drying and a fourth calcination on the material to prepare a catalyst precursor; The catalyst precursor is added with a second urea solution, and subjected to a third hydrothermal treatment in a closed kettle, followed by filtration, washing, a fifth drying, and a fifth calcination to obtain a hydrodemetallization catalyst.

[0006] Preferably, the preparation of the active metal-modified amorphous aluminum oxide compound specifically comprises: The aluminum nitrate is first calcined to obtain an amorphous aluminum oxide compound; The amorphous aluminum oxide compound is first saturatedly impregnated with a solution A containing an active metal component; The impregnated material is subjected to a first drying, a second roasting, and a grinding to obtain an active metal-modified amorphous aluminum oxide compound.

[0007] Preferably, the amorphous aluminum oxide compound is prepared into a metal-modified unit cell distorted pseudo-boehmite, specifically comprising: The amorphous aluminum oxide compound modified with active metal is placed in the first urea solution, stirred evenly, and then placed in a closed kettle for the first hydrothermal treatment and the second hydrothermal treatment; After cooling, the solid material is filtered, washed, and subjected to a second drying to prepare metal-modified unit cell distorted pseudo-boehmite.

[0008] More preferably, the temperature of the first hydrothermal treatment is 90-130° C., and the time is 1-4 h; the temperature of the second hydrothermal treatment is 150-200° C., and the time is 10-16 h.

[0009] Preferably, the active metal component-containing solution A and the active metal component-containing solution B both include Group VIB metals and Group VIII metals.

[0010] More preferably, the active metal component-containing solution A contains 1.0 to 3.5 g / 100 mL of Group VIB metal in terms of oxide content, and 0.3 to 1.0 g / 100 mL of Group VIII metal in terms of oxide content.

[0011] More preferably, the content of Group VIB metal in the solution B containing the active metal component as oxide is 8.5-12.5 g / 100 mL, and the content of Group VIII metal as oxide is 2.2-3.5 g / 100 mL.

[0012] Preferably, the most probable pore diameter of the pseudo-boehmite C is 10-30 nm, and the proportion of the most probable pore diameter of the pseudo-boehmite C to the total pore diameter is 30%-50%.

[0013] More preferably, the mass ratio of the metal-modified unit cell distorted pseudo-boehmite to pseudo-boehmite C is 50% to 90%.

[0014] According to a second aspect of the present application, there is provided a hydrodemetallization catalyst prepared by the method for preparing a hydrodemetallization catalyst as described in any one of the above.

[0015] In the present application, active metals are loaded onto the surface of an amorphous aluminum oxide compound. When the active metal-modified amorphous aluminum oxide compound is subjected to two hydrothermal treatments in a first urea solution, the active metals grow synergistically and form metal-modified unit cell distorted pseudo-boehmite, which can improve the interaction between the active metal and the alumina carrier in the prepared catalyst, and is beneficial to the improvement of the catalyst activity. The structure of the metal-modified unit cell distorted pseudo-boehmite is a petal cluster, which is formed by interwoven clusters of lamellar particles, thereby increasing the 50-100nm pore content in the prepared catalyst. During the third calcination, the metal-modified unit cell distorted pseudo-boehmite is converted into alumina. The above method can increase the number of surface defect sites of alumina, obtain surface defect alumina, and thus improve the activity of the prepared catalyst. When the alumina support is impregnated for the second time with Solution B containing active metal components, the micro-region active metal content of the catalyst's distorted petal-like cluster particles is increased. Furthermore, the distorted petal-like cluster particles are rich in pores, large in size, and have wide pores. The distribution of the catalyst's active metals closely matches the pore structure, making the catalyst highly resistant to metal and carbon deposition and extending its operating cycle. When the catalyst precursor is immersed in a second urea solution for a third hydrothermal treatment, the interaction between the active metals and the alumina support in the prepared catalyst is improved, while flaky particles form on the catalyst's outer surface. These flaky particles accumulate to form open pores that facilitate the diffusion of macromolecular reactants, allowing reactants to quickly enter the catalyst to participate in the reaction. This also enhances the catalyst's surface resistance to metal deposition, improving the catalyst's activity and stability. Furthermore, the prepared catalyst significantly improves the removal rate of metal impurities from residual oil.

[0016] Other features and advantages of the present application will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present application. The purpose and other advantages of the present application can be realized and obtained by the contents indicated in the written description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings: Figure 1 This is an SEM image of the metal-modified unit cell distorted pseudo-boehmite provided in Example 1 of the present application; Figure 2 This is a SEM image of the outer surface of the hydrodemetallization catalyst provided in Example 1 of the present application; Figure 3 This is the XRD spectrum of the metal-modified unit cell distorted pseudo-boehmite and SB powder provided in Example 1 of the present application. DETAILED DESCRIPTION

[0018] In order to make the technical solutions and advantages of the embodiments of the present application more clearly understood, the exemplary embodiments of the present application are further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, and are not an exhaustive list of all the embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other unless they conflict.

[0019] In response to the above problems, the present invention provides a method for preparing a hydrodemetallization catalyst, comprising: S10, preparing an active metal-modified amorphous aluminum oxide compound: The aluminum nitrate is subjected to a first calcination at a temperature of 450-600° C. and a time of 4-8 hours to obtain an amorphous aluminum oxide compound; The amorphous aluminum oxide is first saturatedly impregnated with a solution A containing an active metal component; the amount of the solution A containing the active metal component during the first saturated impregnation is such that the amorphous aluminum oxide powder is completely immersed, and the first saturated impregnation time is 0.5 to 1 hour; The impregnated material is subjected to a first drying, a second calcination, and grinding to obtain a powder with a particle size of less than 20 μm after grinding, more preferably, a powder with a particle size of less than 10 μm after grinding to obtain an active metal-modified amorphous aluminum oxide compound; the first drying temperature is 100~160°C, and the first drying time is 2~8 hours; the second calcination temperature is 450~550°C, and the second calcination time is 4~10 hours.

[0020] S20, preparing the amorphous aluminum oxide compound into metal-modified unit cell distorted pseudo-boehmite: The active metal-modified amorphous aluminum oxide compound is placed in a first urea solution with a concentration of 11.5-18.5 wt% in a mass ratio of 1:2-1:10, magnetically stirred for 10 minutes, and placed in a closed autoclave for a first hydrothermal treatment and a second hydrothermal treatment. The closed autoclave is an autoclave. The temperature of the first hydrothermal treatment is 90-130° C. and the time is 1-4 hours. The temperature of the second hydrothermal treatment is 150-200° C. and the time is 10-16 hours. After cooling, the solid material is filtered, washed, and subjected to a second drying to prepare a metal-modified unit cell distorted pseudo-boehmite. The second drying temperature is 100-160° C. and the second drying time is 6-10 hours.

[0021] During the first hydrothermal treatment, the treatment temperature is low and the treatment time is short, and the active metal-modified amorphous aluminum oxide compound first slowly forms unit cell distorted pseudo-boehmite nuclei in the system; during the second hydrothermal treatment, the unit cell distorted pseudo-boehmite nuclei continue to grow with amorphous aluminum oxide as raw material, facilitating the subsequent formation of the final unit cell distorted pseudo-boehmite; the morphology of the prepared metal-modified unit cell distorted pseudo-boehmite is petal cluster-like and has abundant large pore channels.

[0022] S30, weighing granular pseudo-boehmite C, metal-modified unit cell distorted pseudo-boehmite and sesbania powder; the mass ratio of the metal-modified unit cell distorted pseudo-boehmite to the pseudo-boehmite C is 50% to 90%; after mixing evenly, adding a peptizing agent and kneading into a plastic body, and extruding into strips, the amount of sesbania powder added is 0.5% to 1.5% of the total mass of the metal-modified unit cell distorted pseudo-boehmite and pseudo-boehmite C; the peptizing agent is a 1% acetic acid solution, and the amount of the peptizing agent added is 0.5% to 1.5% of the total mass of the metal-modified unit cell distorted pseudo-boehmite and pseudo-boehmite C. The alumina support is prepared after a third drying and a third calcination. The third drying temperature is 100-160° C., and the third drying time is 6-10 hours. The third calcination temperature is 500-650° C., and the third calcination time is 4-6 hours. The most probable pore size of the pseudo-boehmite C is 10-30 nm, and the proportion of the most probable pore size of the pseudo-boehmite C to the total pore size is 30%-50%. The pseudo-boehmite C can be prepared by any one of the following methods: acid precipitation method, alkali precipitation method, and alcohol aluminum hydrolysis method.

[0023] S40, weighing an alumina support, performing a second impregnation on the alumina support using solution B containing an active metal component by saturation impregnation, and then preparing a catalyst precursor by subjecting the material to a fourth drying and a fourth calcination; the fourth drying temperature is 100-160° C., and the fourth drying time is 6-10 hours; the fourth calcination temperature is 450-550° C., and the fourth calcination time is 4-6 hours.

[0024] S50, adding a second urea solution with a concentration of 11.5-18.5 wt % to the catalyst precursor, with a mass ratio of the catalyst precursor to the second urea solution being 1:2-1:10, performing a third hydrothermal treatment in a closed kettle, and then filtering, washing, performing a fifth drying, and a fifth calcination to obtain a hydrodemetallization catalyst; the third hydrothermal treatment temperature is 150-200° C., and the third hydrothermal treatment time is 10-16 hours; the fifth drying temperature is 100-160° C., and the fifth drying time is 6-10 hours; the fifth calcination temperature is 450-550° C., and the fifth calcination time is 4-6 hours.

[0025] The hydrodemetallization catalyst prepared in the present application comprises an alumina support and an active metal; the active metal is unevenly distributed in the catalyst. The alumina support comprises surface-defect alumina and granular alumina, and the granular alumina has a grain size of 20 to 300 nm. The ratio (H) of the micro-area active metal content of the surface-defect alumina in the alumina support to the micro-area active metal content of the granular alumina, calculated as oxide, is 1.1 to 1.5. The surface-defect alumina has higher activity and larger pores. The high active metal content of the surface-defect alumina in the alumina support can fully utilize the catalyst's pore advantages and the advantages of alumina defect sites, thereby enhancing the catalyst's activity.

[0026] Among them, the surface defect alumina is formed by calcining metal-modified unit cell distorted pseudo-boehmite. Compared with SB powder, the (020) crystal plane spacing d of the metal-modified unit cell distorted pseudo-boehmite is reduced by a percentage δ of 0.5~2%; the particle structure of the surface defect alumina is petal cluster-like, and the size of the petal cluster particles is 3-6μm. The petal cluster particles are formed by interwoven clusters of lamellar alumina grains. The size of the lamellar alumina particles is 0.3~0.8μm, the length and width ratio of the lamellar alumina is 3:1~6:1, and the thickness of the lamellar alumina is 25~45nm.

[0027] The hydrodemetallization catalyst prepared in the present application has a flaky surface particle structure. The flaky particles range in size from 150 nm to 400 nm. The flaky particles are accumulated to form open pores ranging from 100 nm to 300 nm. The coverage of the flaky particles on the catalyst's outer surface is 85% to 100%. The coverage refers to the percentage of the catalyst's outer surface occupied by the flaky particles.

[0028] In the present application, active metals are loaded onto the surface of an amorphous aluminum oxide compound. When the active metal-modified amorphous aluminum oxide compound is subjected to two hydrothermal treatments in a first urea solution, the active metals grow synergistically and form metal-modified unit cell distorted pseudo-boehmite, which can improve the interaction between the active metal and the alumina carrier in the prepared catalyst and is beneficial to the improvement of the catalyst activity. The structure of the metal-modified unit cell distorted pseudo-boehmite is a petal cluster, which is composed of interwoven clusters of lamellar particles, thereby increasing the content of 50-100 nm pores in the prepared catalyst. During the third calcination, the metal-modified unit cell distorted pseudo-boehmite is converted into alumina. The above method can increase the number of surface defect sites of alumina, obtain surface defect alumina, and thus improve the activity of the prepared catalyst. When the alumina support is impregnated for the second time with Solution B containing active metal components, the micro-region active metal content of the catalyst's distorted petal-like cluster particles is increased. Furthermore, the distorted petal-like cluster particles are rich in pores, large in size, and have wide pores. The distribution of the catalyst's active metals closely matches the pore structure, making the catalyst highly resistant to metal and carbon deposition and extending its operating cycle. When the catalyst precursor is immersed in a second urea solution for a third hydrothermal treatment, the interaction between the active metals and the alumina support in the prepared catalyst is improved, while flaky particles form on the catalyst's outer surface. These flaky particles accumulate to form open pores that facilitate the diffusion of macromolecular reactants, allowing reactants to quickly enter the catalyst to participate in the reaction. This also enhances the catalyst's surface resistance to metal deposition, improving the catalyst's activity and stability. Furthermore, the prepared catalyst significantly improves the removal rate of metal impurities from residual oil.

[0029] Furthermore, the solution A containing active metal components and the solution B containing active metal components both include Group VIB metals and Group VIII metals.

[0030] Furthermore, in the solution A containing the active metal components, the content of the Group VIB metal as oxide is 1.0-3.5 g / 100 mL, and the content of the Group VIII metal as oxide is 0.3-1.0 g / 100 mL.

[0031] Furthermore, in the solution B containing the active metal component, the content of the Group VIB metal as oxide is 8.5-12.5 g / 100 mL, and the content of the Group VIII metal as oxide is 2.2-3.5 g / 100 mL.

[0032] Specifically, the Group VIB metal is tungsten (W) and / or molybdenum (Mo), and the Group VIII metal is cobalt (Co) and / or nickel (Ni).

[0033] More specifically, the Group VIB metal oxide is tungsten oxide (WO3) and / or molybdenum oxide (MoO3), and the Group VIII metal oxide is cobalt oxide (CoO) and / or nickel oxide (NiO). In this application, the active metals are Group VIB metals W and Mo, and Group VIII metals Co and Ni. A solution A containing active metal components prepared therefrom is used to perform a first saturation impregnation on an amorphous aluminum oxide compound, thereby modifying the amorphous aluminum oxide compound with the active metal. A solution B containing active metal components prepared therefrom is used to perform a second impregnation on an alumina support, thereby preparing the alumina support as an active metal-modified catalyst precursor. This improves the surface metal deposition resistance and activity of the prepared hydrodemetallization catalyst.

[0034] In order to demonstrate the beneficial effects of the hydrodemetallization catalyst prepared in the present application, the present application provides Examples 1 to 4, and Comparative Examples 1 to 4, wherein the reaction conditions of all Examples and Comparative Examples are shown in Table 1 below.

[0035] This application also provides a blank control, which is a high-quality high-purity pseudo-boehmite developed by Sasol, Germany, produced with high-purity aluminum and higher alcohols as raw materials, hereinafter referred to as SB (Sasol boehmite) powder.

[0036] In this application, scanning electron microscopy is used to characterize the microstructure of the products obtained in the examples, comparative examples, and blank controls, and corresponding scanning electron microscope images (SEM images) can be obtained. For the purpose of simplicity and clarity, this application takes Example 1 as an example and provides SEM images of the metal-modified unit cell distorted pseudo-boehmite and the hydrodemetallization catalyst prepared in Example 1, which are respectively Figure 1 and Figure 2 ; Depend on Figure 1 and Figure 2 It can be seen that the metal-modified unit cell distorted pseudo-boehmite structure is in the shape of petals, which are composed of clusters of interwoven lamellar particles, thereby increasing the content of 50-100nm pores in the prepared catalyst; the outer surface of the catalyst is flaky particles, which accumulate to form open pores that are conducive to the diffusion of large molecular reactants, allowing the reactants to quickly enter the interior of the catalyst to participate in the reaction, while enhancing the catalyst surface's resistance to metal deposition, thereby improving the activity and stability of the catalyst.

[0037] Since the first urea solution was replaced by an ammonia solution in Comparative Example 1 and the first urea solution was replaced by an ammonium carbonate solution in Comparative Example 2, the products prepared therefrom did not produce a petal cluster structure.

[0038] In this application, an X-ray diffractometer is used to characterize the physical structure of the products obtained in the examples, comparative examples and blank controls, and the corresponding XRD spectra are obtained. For the purpose of simplicity, this application uses Example 1 as an example to provide the XRD spectra of SB powder and the metal-modified unit cell distorted pseudo-boehmite P1 prepared in Example 1, as shown in FIG. Figure 3 shown.

[0039] Depend on Figure 3 As shown, the metal-modified unit cell distorted pseudo-boehmite prepared in Example 1 of the present application has a smaller (020) crystal plane spacing than the SB powder.

[0040] The XRD spectra of the metal-modified unit cell distorted pseudo-boehmite prepared in Examples 1 to 4 and the XRD spectra of the SB powder in the blank control are used to calculate the percentage reduction of the (020) interplanar spacing of Examples 1 to 4 compared with the blank control, specifically including: The crystal plane corresponding to the characteristic peak of 11.1°~17.5° 2θ in the XRD spectrum is the (020) crystal plane; By Bragg's law , , respectively calculate the interplanar spacing of the blank control and the metal-modified unit cell distorted pseudo-boehmite prepared in Examples 1 to 4 ; Where n represents the diffraction order, n is an integer, λ represents the wavelength of the incident X-ray, and θ represents the diffraction angle, that is, the angle between the incident beam and the (020) crystal plane. represents the (020) interplanar spacing of SB powder, Respectively represent the (020) crystal plane spacing of the metal-modified unit cell distorted pseudo-boehmite prepared in Example 1 to Example 4; The percentage reduction of the (020) interplanar spacing of Examples 1 to 4 compared to the blank control was calculated using the following formula: , ; Where, Respectively represent the percentage reduction of the (020) interplanar spacing of Examples 1 to 4 compared with the blank control.

[0041] The metal-modified unit cell distorted pseudo-boehmite prepared by the preparation method provided in the present application has a (020) crystal plane spacing reduction percentage δ of 0.5-2% compared to the blank control.

[0042] Table 1 Reaction conditions

[0043] In this application, the properties and catalytic effects of the products obtained in the examples and comparative examples were measured by the following method: Pore ​​structure characterization: First, the pore volume, specific surface area and average pore diameter of the sample were determined using the low-temperature nitrogen adsorption-desorption method (BET).

[0044] Characterization of micro-area composition: The micro-area composition of the sample was analyzed using a scanning electron microscope equipped with an energy dispersive spectrometer (SEM-EDS). In the experiment, 10 flaky particle accumulation micro-areas and granular particle accumulation micro-areas were selected as measurement areas. The content of active metal oxides in the corresponding areas was measured and the average value was taken to calculate the H value.

[0045] Microstructure characterization: Scanning electron microscopy (SEM) was used to characterize the microstructure of the samples.

[0046] Phase characterization: X-ray diffractometer was used to characterize the sample phase.

[0047] Catalytic effect: Using residual oil as the raw material, the content of metal impurities nickel and vanadium (Ni+V) in the raw material oil is 193μg / g. The reaction conditions are as follows: reaction temperature 385℃, pressure 14.5MPa, liquid hourly volume space velocity 0.55h -1 The volume ratio of hydrogen to oil was 850. The contents of nickel and vanadium metal impurities in the generated oil were determined after 500 and 3000 hours of reaction, and the removal rate of metal impurities was calculated. The evaluation results are shown in Table 2.

[0048] The properties and catalytic effects of the products obtained in the examples and comparative examples are shown in Table 2 below: Table 2 Properties and catalytic effects of the products obtained in Examples and Comparative Examples

[0049] As can be seen from Table 2, the specific surface area and pore volume of the hydrodemetallization catalyst prepared in the examples of the present application are both high. The prepared catalyst has a low content of 10-30 nm pores and a high content of 50-100 nm pores. The size of the pores on the catalyst surface is 100-300 nm, which can improve the activity of the catalyst. The relative demetallization rate at 500 hours and the relative demetallization rate at 3000 hours are significantly improved. The catalyst has a good effect in removing metal impurities and can prevent the deposition of metal impurities such as nickel and vanadium. It has a high initial activity, high stability over a long period of time, and a long service life.

[0050] The catalysts prepared by Comparative Examples 1 and 2 have insufficient surface defects, relatively small specific surface area and pore volume, a relatively high content of 10-30 nm pores, and a relatively low content of 50-100 nm pores. In summary, the catalysts prepared by Comparative Examples 1 and 2 have insufficient activity, metal-tolerance, and carbon-tolerance capabilities, and are difficult to meet the use requirements of heavy oil and residual oil hydrodemetallization catalysts.

[0051] In Comparative Example 3, solution A containing active metal components was not used for the first saturated impregnation. As shown in the measurement results in Table 2, although the specific surface area and pore volume of the prepared catalyst were relatively large, and the content of 50-100 nm pores was significantly higher, the relative demetallization rates at 500 hours and 3000 hours were both lower than those of Examples 1 to 4. In summary, the operating cycle of the catalyst prepared in Comparative Example 3 was not long enough, and the relative demetallization effect was not good enough.

[0052] In Comparative Example 4, step S50 was not performed, and the catalyst precursor prepared in S40 was directly used as the obtained product. No second urea solution was added, and no third hydrothermal treatment was performed. The measurement results in Table 2 show that the surface particle morphology of the obtained product is granular, and the surface pore size is 20-60 nm. The surface pores are small, which is not conducive to the diffusion of macromolecular reactants, and the activity and stability are poor.

[0053] The present application also provides a hydrodemetallization catalyst prepared by the method for preparing a hydrodemetallization catalyst as described above. Since the above method is used for preparation, it can be considered to have the same beneficial effects as the above catalysts. For the purpose of brevity, it will not be described in detail here.

[0054] It should be noted that the reaction conditions such as the temperature and time of the first roasting, the first drying, the second roasting, the second drying, the third drying, the third roasting, the fourth roasting, the fourth drying, the fifth roasting, and the fifth drying in the present application are within the range provided above. When the temperature is low, the time is increased accordingly. When the temperature is high, the time is shortened accordingly. Only examples of a portion of data are provided in Table 1, which are not intended to limit the reaction conditions in the present application.

[0055] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0056] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0057] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A method for preparing a hydrodemetallization catalyst, characterized in that: include: Preparation of active metal modified amorphous aluminum oxide compounds; Amorphous aluminum oxide is prepared into metal-modified unit cell distorted pseudo-boehmite; Pseudoboehmite C, metal-modified unit cell distorted pseudoboehmite and sesbania powder are weighed and mixed uniformly, a peptizing agent is added, kneaded and formed, and then subjected to a third drying and a third calcination to prepare an alumina support; Weighing an alumina support, performing a second impregnation on the alumina support using solution B containing an active metal component in a saturated impregnation manner, and then performing a fourth drying and a fourth calcination on the material to prepare a catalyst precursor; The catalyst precursor is added with a second urea solution, and subjected to a third hydrothermal treatment in a closed kettle, followed by filtration, washing, a fifth drying, and a fifth calcination to obtain a hydrodemetallization catalyst.

2. The method for preparing a hydrodemetallization catalyst according to claim 1, wherein The method for preparing an active metal-modified amorphous aluminum oxide compound comprises: The aluminum nitrate is first calcined to obtain an amorphous aluminum oxide compound; The amorphous aluminum oxide compound is first saturatedly impregnated with a solution A containing an active metal component; The impregnated material is subjected to a first drying, a second roasting, and a grinding to obtain an active metal-modified amorphous aluminum oxide compound.

3. The method for preparing a hydrodemetallization catalyst according to claim 1, wherein The amorphous aluminum oxide compound is prepared into a metal-modified unit cell distorted pseudo-boehmite, specifically comprising: The amorphous aluminum oxide compound modified with active metal is placed in the first urea solution, stirred evenly, and then placed in a closed kettle for the first hydrothermal treatment and the second hydrothermal treatment; After cooling, the solid material is filtered, washed, and subjected to a second drying to prepare metal-modified unit cell distorted pseudo-boehmite.

4. The method for preparing a hydrodemetallization catalyst according to claim 3, wherein The temperature of the first hydrothermal treatment is 90~130℃, and the time is 1~4h; the temperature of the second hydrothermal treatment is 150~200℃, and the time is 10~16h.

5. The method for preparing the hydrodemetallization catalyst according to claim 2, wherein The active metal component-containing solution A and the active metal component-containing solution B both include Group VIB metals and Group VIII metals.

6. The method for preparing a hydrodemetallization catalyst according to claim 5, wherein: In the solution A containing the active metal component, the content of the Group VIB metal as oxide is 1.0-3.5 g / 100 mL, and the content of the Group VIII metal as oxide is 0.3-1.0 g / 100 mL.

7. The method for preparing a hydrodemetallization catalyst according to claim 6, wherein: In the solution B containing the active metal component, the content of the Group VIB metal as oxide is 8.5-12.5 g / 100 mL, and the content of the Group VIII metal as oxide is 2.2-3.5 g / 100 mL.

8. The method for preparing a hydrodemetallization catalyst according to claim 1, wherein The most probable pore size of the pseudo-boehmite C is 10-30 nm, and the proportion of the most probable pore size of the pseudo-boehmite C to the total pore size is 30%-50%.

9. The method for preparing a hydrodemetallization catalyst according to claim 8, wherein: The mass ratio of the metal-modified unit cell distorted pseudo-boehmite to pseudo-boehmite C is 50% to 90%.

10. A hydrodemetallization catalyst prepared by the method for preparing a hydrodemetallization catalyst according to any one of claims 1 to 9.

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