A process for the preparation of a hydrodemetallation catalyst

Abstract

The application aims to provide a preparation method of a hydrodemetallization catalyst, and belongs to the field of catalyst preparation, and the steps are as follows: preparing phosphorus modified elliptical sheet-like pseudo-boehmite; impregnating the phosphorus modified elliptical sheet-like pseudo-boehmite with impregnation liquid I containing active components, drying the impregnated material, and obtaining modified pseudo-boehmite P1; mixing and kneading the modified pseudo-boehmite P1 and pseudo-boehmite P2 into a shape, drying and calcining the shaped material, and preparing an alumina carrier; impregnating the alumina carrier with impregnation liquid II containing active components, drying and calcining the impregnated material, and obtaining a hydrodemetallization catalyst. The catalyst has high and adjustable content of large pores, and the large pore channels, large pore surface acidity, and active metal content in the catalyst are highly matched. The catalyst has the characteristics of high reaction activity and strong metal impurity capacity, and is particularly suitable for the field of heavy oil and residue oil hydroprocessing.

Description

Technical Field

[0001] This invention belongs to the field of catalyst preparation, specifically relating to a method for preparing a hydrogenation demetallization catalyst. Background Technology

[0002] With increasingly stringent environmental regulations and the increasing heaviness of crude oil, efficient conversion of heavy oil has become a significant trend in refining technology development. Fixed-bed residue hydrotreating technology is an effective means to achieve efficient conversion of heavy oil. However, due to the high viscosity, high impurity content, and complex molecular composition of residue oil, the hydrotreating reaction is challenging. It requires the effective removal of impurities such as metals, sulfur, nitrogen, and residual carbon from the residue oil through catalytic reactions. A single catalyst is insufficient; a matching packing system with catalysts of different functions, shapes, and sizes is necessary to achieve high activity and long-term industrial operation. Residue hydrotreating catalysts typically include protective catalysts, demetallizing catalysts, desulfurization catalysts, and denitrification catalysts, each with additional functions. The demetallizing catalyst is one of the main catalysts in residue hydrotreating technology. Its role is to remove metals such as Ni and V from the residue oil while protecting the desulfurization catalyst. It must not only remove metal impurities from the feed but also accommodate as many of these metals and coke impurities as possible.

[0003] CN201510191156.7 discloses a heavy oil hydrogenation catalyst and its preparation method. The preparation method of the catalyst includes: firstly, preparing sheet-like γ-polycrystalline alumina; then adding the sheet-like γ-polycrystalline alumina powder to a binder and an extrusion aid, kneading, molding, drying and calcining to obtain an alumina support; finally, loading an active metal onto the obtained alumina support using conventional methods. The preparation method of sheet-like γ-polycrystalline alumina includes the following steps: (1) mixing inorganic aluminum salt, low-carbon alcohol and / or water, and low-carbon epoxy alkane evenly to form a gel, and then aging the gel; (2) soaking the gel obtained in step (1) in low-carbon alcohol, and then drying and calcining; (3) immersing the material obtained in step (2) in ammonia water for closed hydrothermal treatment, solid-liquid separation, drying, and obtaining sheet-like γ-polycrystalline alumina powder. This invention adjusts the pore structure of an alumina support by adding lamellar polycrystalline γ-alumina to the alumina support. However, the preparation process of lamellar polycrystalline γ-alumina is relatively complex. On the other hand, the matching degree between the active metal component and the catalyst pores needs to be further improved.

[0004] CN201910265729.4 discloses a method for preparing a hydrogenation demetallization catalyst. The preparation method includes: (1) preparing rod-shaped alumina clusters; (2) impregnating the rod-shaped alumina clusters of step (1) with an impregnation solution containing hydrogenation active component I and drying to obtain modified rod-shaped alumina clusters, mixing the modified rod-shaped alumina clusters with boehmite, drying and calcining to obtain support I; (3) mixing the support I obtained in step (2) with ammonium bicarbonate and water and then sealing and heat-treating, and drying and calcining the treated material to obtain support II; (4) impregnating the support II of step (3) with an impregnation solution containing hydrogenation active component II, and drying and calcining the support to obtain a hydrogenation demetallization catalyst. This method uses rod-shaped alumina clusters modified with active components to adjust the pore structure and distribution of active metals in the catalyst, thereby improving the activity of the catalyst. However, the pores formed by the accumulation of rod-shaped particles in the rod-shaped alumina clusters are relatively large, which is not conducive to the full exertion of the hydrogenation activity of the catalyst. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a hydrodemetallization catalyst. The catalyst of this invention has a high and adjustable macropore content, and the macropore channels, macropore surface acid properties, and active metal content are highly matched. This catalyst exhibits high reactivity and strong tolerance to metal impurities, making it particularly suitable for the hydrotreating of heavy and residual oils.

[0006] The present invention adopts the following technical solution:

[0007] A method for preparing a hydrogenation demetallization catalyst includes the following steps:

[0008] The first step is to prepare phosphorus-modified elliptical lamellar pseudoboehmite;

[0009] The second step involves impregnating phosphorus-modified elliptical layered boehmite with impregnation solution I containing active components. The impregnated material is then dried to obtain modified boehmite P1.

[0010] The third step involves mixing and molding modified boehmite P1 and boehmite P2, and then drying and calcining the molded material to obtain an alumina carrier.

[0011] The fourth step involves impregnating the alumina support with impregnation solution II containing active components. The impregnated material is then dried and calcined to obtain the hydrogenation demetallization catalyst.

[0012] Furthermore, the phosphorus-modified elliptical lamellar pseudoboehmite particles described in the first step are elliptical lamellar in shape, with a length of 2-5 μm, a width of 1-2 μm, a thickness of 100-200 nm, and a phosphorus content of 1wt%-10wt% (based on elemental P).

[0013] Further, the preparation method of the phosphorus-modified elliptical lamellar pseudoboehmite in the first step is as follows: the pseudoboehmite is impregnated with a phosphorus-containing solution, and the impregnated pseudoboehmite is dried and calcined to obtain phosphorus-modified alumina; the above phosphorus-modified alumina is sequentially impregnated in organic alkali solution A1 and organic alkali solution A2 for the first and second hydrothermal treatments, and the treated material is dried and then impregnated again in a phosphorus-containing solution II, and the impregnated material is dried to obtain phosphorus-modified elliptical lamellar pseudoboehmite.

[0014] Furthermore, both phosphorus-containing solution one and phosphorus-containing solution two include one or a mixture of several of the following: phosphoric acid solution, ammonium monohydrogen phosphate solution, ammonium dihydrogen phosphate solution, and ammonium phosphate solution. Phosphorus-containing solution one and phosphorus-containing solution two may be the same or different, preferably different.

[0015] Furthermore, the first phosphorus-containing solution is a phosphoric acid solution with a concentration of 0.1-0.5M, and the second phosphorus-containing solution is an ammonium phosphate solution with a concentration of 0.05-0.3M. The amounts of the first and second phosphorus-containing solutions are such that the solid material is saturated with adsorption.

[0016] Furthermore, the drying temperature is 100-160℃, and the drying time is 1-6 hours; the calcination temperature is 450-550℃, and the calcination time is 1-6 hours.

[0017] Furthermore, both organic base solutions A1 and A2 include one of tetramethylammonium hydroxide solution, tetraethylaluminum hydroxide solution, and tetrapropylammonium hydroxide solution, preferably tetraethylammonium hydroxide solution. Organic base solutions A1 and A2 may be the same or different, but are preferably the same.

[0018] Furthermore, the organic base concentration in organic base solution A1 is 0.8%-2.0%, and the organic base concentration in organic base solution A2 is 3.5%-12.5%.

[0019] Furthermore, both the first and second hydrothermal treatments are sealed hydrothermal treatments, with the sealed container preferably being a high-pressure reactor. The temperature of the first hydrothermal treatment is 80-120℃, and the treatment time is 1-4 hours. The temperature of the second hydrothermal treatment is 140-180℃, and the treatment time is 4-10 hours.

[0020] Furthermore, in the second step, the impregnation solution I containing active components is a Mo-Ni-P solution containing MoO3 and NiO, wherein the MoO3 content in the solution is 0.5-3.5 g / 100 mL, the NiO content is 0.1-1 g / 100 mL, the solution volume is sufficient to saturate the solid material with adsorption, the impregnation time is 0.5-1.5 hours, and the drying conditions are 100-160℃ for 2-8 hours.

[0021] Furthermore, the pseudoboehmite P2 mentioned in the third step has a probable pore size of 10-25 nm, and the content of 10-25 nm pores accounts for more than 50% of the total pore volume. The mass ratio of modified pseudoboehmite P1 to pseudoboehmite P2 is 1:4-2:3.

[0022] Furthermore, in the third step, the drying temperature is 100-160℃ and the drying time is 6-10 hours; the calcination temperature is 550-650℃ and the calcination time is 4-6 hours.

[0023] Furthermore, the impregnation solution II containing active components mentioned in step four is a Mo-Ni-P solution containing MoO3 and NiO. The concentration of MoO3 in the solution is 7.5g / 100mL-13.5g / 100mL, and the concentration of NiO is 1.8g / 100mL-3.5g / 100mL. Equal volume spray impregnation is preferred during impregnation. The drying conditions are 80-120℃ and 4-8 hours. The calcination conditions are 400-550℃ and 4-8 hours.

[0024] The beneficial effects of this invention are as follows:

[0025] 1. In the preparation of alumina support in this invention, pseudoboehmite with an elliptical lamellar morphology is selected as part of the raw material. The elliptical lamellar pseudoboehmite is stacked to form a large number of macropores. After the support is formed, the macropores are well preserved, thereby meeting the requirement of macromolecular reactants for macropores in the heavy residue oil hydrotreating process.

[0026] 2. Elliptical lamellar pseudoboehmite is modified with phosphorus, and phosphorus is introduced into the pseudoboehmite in two steps. This effectively increases the acid content on the surface of the corresponding alumina support while improving the hydroxyl structure on the support surface, thereby enhancing the catalytic activity of the final catalyst.

[0027] 3. Pre-impregnating some active metal components into elliptical lamellar pseudo-hydroalumina can effectively control the distribution of active components in the final catalyst. This results in a high content of active metals on the surface of the macropores formed by the accumulation of elliptical lamellar alumina in the catalyst, well-developed pores, high acid content, and a rational hydroxyl structure. This improves the utilization rate of the macropores, enhances the catalyst's resistance to metal deposition and carbon buildup, and enables the catalyst to have both high activity and a long operating cycle. Attached Figure Description

[0028] Figure 1 The image shows a SEM image of the elliptical sheet-like pseudo-thin aluminum prepared in Example 1. Detailed Implementation

[0029] 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.

[0030] Sample pore structure characterization: The sample pore structure was characterized using a Micromeritics Trister 3000 nitrogen physisorption instrument.

[0031] Characterization of pore diameters greater than 100 nm: The pore distribution of the samples was characterized using a fully automated mercury porosimeter (AutoPore 9500) from the USA.

[0032] Sample microstructure characterization: The microstructure of the samples was characterized using a Hitachi SU8220 scanning electron microscope (SEM).

[0033] Relative demetallization rate: The demetallization rate of a catalyst is measured, and its relative demetallization rate is defined as 100%. The relative impurity removal rate is calculated as the ratio of the impurity removal rate of other catalysts to the defined impurity removal rate of the catalyst × 100%.

[0034] Example 1

[0035] (1) Weigh an appropriate amount of boehmite and saturate it with a 0.25M phosphoric acid solution. After impregnation, dry the boehmite at 140℃ for 4 hours and calcine it at 450℃ for 5 hours to obtain γ-phase alumina. Transfer the above γ-phase alumina powder into the polytetrafluoroethylene liner of the autoclave and add a 1.4wt% tetraethylammonium hydroxide solution to completely submerge the γ-phase alumina powder. Stir the mixture for 45 minutes. After sealing the autoclave, perform hydrothermal treatment at 95℃ for 3 hours. After treatment, filter the material and set the filter cake aside. The filter cake was transferred again into a polytetrafluoroethylene-lined autoclave, and a 9 wt% tetraethylammonium hydroxide solution was added to completely submerge the solid material. The mixture was stirred for 45 minutes, and after sealing the autoclave, it was hydrothermally treated at 155°C for 7.5 hours. The treated material was then filtered, and the filter cake was dried at 140°C for 4 hours to obtain phosphorus-modified boehmite. The phosphorus-modified boehmite was then saturated again with a 0.2 M ammonium phosphate solution, and the impregnated material was dried at 140°C for 4 hours to obtain phosphorus-modified elliptical lamellar boehmite. The scanning electron microscope image of the sample is shown below. Figure 1 .

[0036] (2) The phosphorus-modified elliptical layered pseudoboehmite was saturated with a Mo-Ni-P solution with a MoO3 concentration of 2.0 g / 100 mL and a NiO concentration of 0.5 g / 100 mL. After saturation, the material was dried at 140 °C for 4 hours to obtain the active metal modified material.

[0037] (3) Weigh 600g of pseudoboehmite P2 (10-25nm pores account for 58.5% of the total pore volume), 310g of the active metal modified material from step (2), and 4.5g of guar gum powder. Mix the above materials evenly, extrude them into strips, dry the strips at 140℃ for 4 hours, and calcine them at 600℃ for 5 hours to obtain an alumina carrier.

[0038] (4) Weigh 100 g of the alumina support from step (3), and saturate the alumina support with a Mo-Ni-P solution with a MoO3 concentration of 9.5 g / 100 mL and a NiO concentration of 2.2 g / 100 mL. After impregnation, the support is dried at 140 °C for 5 hours and calcined at 450 °C for 4 hours to obtain the hydrogenation demetallization catalyst C-1 of the present invention. The properties of the catalyst are shown in Table 1.

[0039] Example 2

[0040] Same as Example 1, except that in step (1) the concentration of phosphoric acid solution is 0.35M. The concentration of tetraethylammonium hydroxide in organic base solution A1 is 1.6%, the first hydrothermal treatment temperature is 105℃, and the treatment time is 2 hours. The concentration of tetraethylammonium hydroxide in organic base solution A2 is 6.5%, the second hydrothermal treatment temperature is 165℃, and the treatment time is 6 hours. The concentration of ammonium phosphate solution is 0.15M; in step (2) the concentration of MoO3 in Mo-Ni-P solution is 1.5g / 100mL, and the concentration of NiO is 0.4g / 100mL; in step (3) the amount of active metal modified material added is 240g; in step (4) the concentration of MoO3 in Mo-Ni-P solution is 8.5g / 100mL, and the concentration of NiO is 2.0g / 100mL, thus obtaining the hydrogenation demetallization catalyst C-2 of the present invention. The properties of the catalyst are shown in Table 1.

[0041] Example 3

[0042] Same as Example 1, except that the phosphoric acid solution concentration in step (1) is 0.45M. Tetraethylammonium hydroxide in organic base solution A1 is replaced with tetrapropylammonium hydroxide, with a solution concentration of 1.8%, the first hydrothermal treatment temperature is 85℃, and the treatment time is 4 hours. Tetraethylammonium hydroxide in organic base solution A2 is replaced with tetrapropylammonium hydroxide, with a solution concentration of 4.5%, the second hydrothermal treatment temperature is 175℃, and the treatment time is 4.5 hours. The ammonium phosphate solution concentration is 0.1M; in step (2), the MoO3 concentration in the Mo-Ni-P solution is 2.5g / 100mL, and the NiO concentration is 0.6g / 100mL; in step (3), the amount of active metal modified material added is 380g; in step (4), the MoO3 concentration in the Mo-Ni-P solution is 7.5g / 100mL, and the NiO concentration is 1.8g / 100mL, thus obtaining the hydrogenation demetallization catalyst C-3 of this invention. The catalyst properties are shown in Table 1.

[0043] Example 4

[0044] Same as Example 1, except that in step (1) the concentration of phosphoric acid solution is 0.15M. The concentration of tetraethylammonium hydroxide in organic base solution A1 is 1.0%, the first hydrothermal treatment temperature is 115℃, and the treatment time is 1 hour. The concentration of tetraethylammonium hydroxide in organic base solution A2 is 12%, the second hydrothermal treatment temperature is 145℃, and the treatment time is 9 hours. The concentration of ammonium phosphate solution is 0.25M; in step (2) the concentration of MoO3 in Mo-Ni-P solution is 1.0g / 100mL, and the concentration of NiO is 0.3g / 100mL; in step (3) the amount of active metal modified material added is 150g; in step (4) the concentration of MoO3 in Mo-Ni-P solution is 10.5g / 100mL, and the concentration of NiO is 2.5g / 100mL, thus obtaining the hydrogenation demetallization catalyst C-4 of the present invention. The properties of the catalyst are shown in Table 1.

[0045] Comparative Example 1

[0046] Same as Example 1, except that in step (1) tetraethylammonium hydroxide was replaced with ammonia water of the same concentration. After hydrothermal treatment, no elliptical lamellar crystals were observed to form in the microstructure of the material. Comparative catalyst C-5 was obtained, and the properties of the catalyst are shown in Table 1.

[0047] Comparative Example 2

[0048] Same as Example 1, except that in step (1) tetraethylammonium hydroxide was replaced with sodium hydroxide of the same concentration. After hydrothermal treatment, no elliptical lamellar crystals were observed to form in the microstructure of the material. Comparative catalyst C-6 was obtained. The properties of the catalyst are shown in Table 1.

[0049] Comparative Example 3

[0050] Same as Example 1, except that the pseudoboehmite was not modified with phosphorus, but the same amount of phosphorus was introduced into the support by impregnation after the support was formed. At the same time, the impregnation process in step (2) was omitted, and a one-step impregnation method was used in step (4) to prepare the comparative catalyst C-7 with the same active metal loading. The properties of the catalyst are shown in Table 1.

[0051] Table 1 Catalyst Properties

[0052]

[0053] Catalytic performance evaluation:

[0054] Using a certain residue oil as feedstock, the properties of which are shown in Table 2, the catalytic performance of the hydrodemetallization catalysts (C-1-C-7) prepared in the above examples and comparative examples was evaluated under the following conditions: reaction temperature 380℃, pressure 13.5 MPa, and liquid hourly space velocity 0.85 h⁻¹. -1The activity evaluation results after 200 hours of operation with a hydrogen-to-oil volume ratio of 900 are shown in Table 3. As the operating time increases, the catalyst activity decreases. In order to maintain the catalyst activity to meet production requirements, it is necessary to raise the temperature of the catalyst bed. The temperature rise of the catalyst bed after 5000 hours of operation is shown in Table 4.

[0055] Table 2 Properties of Crude Oil

[0056]

[0057] Table 3 Comparison of Hydrodemetallization Performance of Catalysts

[0058]

[0059] As can be seen from the data in Table 3, the catalyst prepared by the method of the present invention has higher hydrogenation demetallization activity compared with the comparative catalyst.

[0060] Table 4

[0061]

[0062] As can be seen from the results in Table 4, the hydrogenation demetallization catalyst provided by this invention still has high activity after 5000 hours of reaction.

Claims

1. A method for preparing a hydrogenation demetallization catalyst, characterized in that: Includes the following steps: The first step is to prepare phosphorus-modified elliptical lamellar pseudoboehmite. The preparation method is as follows: pseudoboehmite is impregnated with a phosphorus-containing solution, and the impregnated pseudoboehmite is dried and calcined to obtain phosphorus-modified alumina; the above phosphorus-modified alumina is sequentially impregnated with organic alkali solution A1 and organic alkali solution A2 for the first and second hydrothermal treatments, and the treated material is dried and then impregnated again with a phosphorus-containing solution II. The impregnated material is dried to obtain phosphorus-modified elliptical lamellar pseudoboehmite. Both phosphorus-containing solution one and phosphorus-containing solution two include one or a mixture of several of phosphoric acid solution, monoammonium hydrogen phosphate solution, diammonium hydrogen phosphate solution and ammonium phosphate solution. Phosphorus-containing solution one and phosphorus-containing solution two may be the same or different. Both organic base solution A1 and organic base solution A2 include one of tetramethylammonium hydroxide solution and tetrapropylammonium hydroxide solution, and organic base solution A1 and organic base solution A2 may be the same or different. The organic base concentration in organic base solution A1 is 0.8%-2.0%, and the organic base concentration in organic base solution A2 is 3.5%-12.5%. Both the first and second hydrothermal treatments are sealed hydrothermal treatments. The temperature of the first hydrothermal treatment is 80-120℃ and the treatment time is 1-4 hours. The temperature of the second hydrothermal treatment is 140-180℃ and the treatment time is 4-10 hours. The second step involves impregnating phosphorus-modified elliptical layered boehmite with impregnation solution I containing active components. The impregnated material is then dried to obtain modified boehmite P1. The impregnation solution I containing the active component is a Mo-Ni-P solution containing MoO3 and NiO. The MoO3 content in the solution is 0.5-3.5 g / 100 mL, and the NiO content is 0.1-1 g / 100 mL. The solution volume is sufficient to saturate the solid material with adsorption. The impregnation time is 0.5-1.5 hours. The drying conditions are 100-160℃ and drying for 2-8 hours. The third step involves mixing and molding modified boehmite P1 and boehmite P2, and then drying and calcining the molded material to obtain an alumina carrier. The fourth step involves impregnating the alumina support with impregnation solution II containing active components. The impregnated material is then dried and calcined to obtain the hydrogenation demetallization catalyst. The impregnation solution II containing active components is a Mo-Ni-P solution containing MoO3 and NiO, wherein the concentration of MoO3 in the solution is 7.5g / 100mL-13.5g / 100mL, and the concentration of NiO is 1.8g / 100mL-3.5g / 100mL. The drying conditions are 80-120℃ for 4-8 hours, and the calcination conditions are 400-550℃ for 4-8 hours.

2. The method for preparing a hydrogenation demetallization catalyst according to claim 1, characterized in that: The phosphorus-modified elliptical lamellar pseudoboehmite particles described in the first step are elliptical lamellar particles with a length of 2-5 μm, a width of 1-2 μm, a thickness of 100-200 nm, and a phosphorus content of 1wt%-10wt% (based on elemental P).

3. The method for preparing a hydrogenation demetallization catalyst according to claim 1, characterized in that: The first phosphorus-containing solution is a phosphoric acid solution with a concentration of 0.1-0.5M, and the second phosphorus-containing solution is an ammonium phosphate solution with a concentration of 0.05-0.3M. The amounts of the first and second phosphorus-containing solutions are such that the solid material is saturated with adsorption. The drying temperature is 100-160℃, and the drying time is 1-6 hours; the calcination temperature is 450-550℃, and the calcination time is 1-6 hours.

4. 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 6-10 hours; the calcination temperature is 550-650℃, and the calcination time is 4-6 hours. The pseudoboehmite P2 mentioned in the third step has a pore size of 10-25 nm, and the content of 10-25 nm pores accounts for more than 50% of the total pore volume. The mass ratio of modified pseudoboehmite P1 to pseudoboehmite P2 is 1:4-2:3.

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