Preparation method of heavy oil hydrodenitrogenation and hydrodecarbon residue catalyst

Abstract

This invention discloses a method for preparing a catalyst for hydrodenitrification and decarbonization of heavy oil, comprising the following steps: (1) mixing boehmite powder, boron-containing micron-sized spherical activated carbon, and water into a slurry, then separating the solid and liquid phases, drying the solid phase material, then kneading, molding, drying, and calcining under an inert atmosphere to obtain an alumina support precursor, and then loading boron to obtain a boron-modified alumina support precursor; (2) adding the boron-modified alumina support precursor and propylene oxide aqueous solution into a closed high-pressure reactor, reacting at 60-100℃ for 1-4 hours, then raising the temperature to 110-180℃ for 2-6 hours, drying, and calcining to obtain an alumina support, and then loading hydrogenation active components to obtain the catalyst product. The catalyst prepared by this method has a worm-like particle morphology on its surface, and the pores formed by the accumulation of worm-like particles are open. The catalyst also has suitable Brønsted acid and Lewis acid content. This catalyst is suitable for hydrodenitrification and decarbonization reactions of inferior heavy oil.

Description

Technical Field

[0001] This invention belongs to the field of catalyst preparation, specifically relating to a method for preparing a catalyst for the hydrodenitrification and decarbonization of heavy oil. Background Technology

[0002] With the increasingly acute contradiction between the global trend of heavier and lower-quality crude oil and the diversified and lighter demand for petrochemical products, the combined process of residue hydrotreating and catalytic cracking is playing an increasingly important role. Residue hydrotreating technology primarily provides qualified feedstock for catalytic cracking. As a feedstock for catalytic cracking, the performance of the residue hydrotreating product, especially its metal, sulfur, nitrogen, and carbon residue values, has a significant impact on the catalytic cracking process. Among these, the carbon residue value of the residue hydrotreating product has a greater impact on catalytic cracking. The carbon residue value of heavy oil represents the tendency of high-boiling-point components to coke during processing, and the carbon residue conversion rate is an important indicator of the residue hydrotreating process. Feedstock with high carbon residue values ​​results in high coke and slurry oil yields during catalytic cracking, which significantly affects the operational stability and product distribution of the catalytic cracking unit. Reducing the carbon residue value of the oil produced by the residue hydrotreating unit will help improve the performance of the catalytic cracking feedstock, improve product distribution, and contribute to improving the economic efficiency of the combined residue hydrotreating and catalytic cracking unit.

[0003] CN103785397A discloses a hydrogenation decarbonization catalyst and its preparation method. The preparation method of the catalyst includes the following steps: (1) after neutralization reaction of acidic aluminum salt aqueous solution and alkali metal aluminate aqueous solution, an alkaline precipitant or alkaline aluminate aqueous solution is introduced to adjust the pH of the slurry to 8.5-9.7, and the slurry is aged at 150-220℃ for 0.1-2 hours; (2) after aging in step (1), the material is filtered, washed, dried, and then 10-40wt% aluminum ammonium carbonate is added for molding; (3) after molding, the material is loaded with active components, dried, and calcined to obtain the hydrogenation decarbonization catalyst. Although the catalyst has a high pore content of 6-10nm and a certain amount of pores of 100nm and above, the pores on the catalyst surface are not open, which is not conducive to the entry of reactant molecules into the interior of the catalyst.

[0004] CN111821989A discloses a catalyst for hydrodenitrification of residual oil and its preparation method. The catalyst comprises a modified alumina-based support, molybdenum and nickel metal components, wherein the modified alumina-based support contains tungsten and cobalt metal components. The modified alumina-based support includes a main modified alumina and rod-shaped modified alumina. The main modified alumina is modified alumina with micron-sized pores, wherein at least some of the rod-shaped modified alumina is distributed on the outer surface of the main modified alumina and in the micron-sized pores with a pore diameter D of 3-7 μm. The catalyst prepared by this method has a rod-shaped surface structure, but the bonding strength between the rod-shaped alumina grown on the surface and the main alumina needs further improvement. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for preparing a catalyst for hydrodenitrification and decarbonization of heavy oil. The catalyst prepared by this method has a worm-like particle morphology on its surface, with open channels formed by the accumulation of worm-like particles. Furthermore, the catalyst has suitable contents of Brønsted acid and Lewis acid. This catalyst is suitable for hydrodenitrification and decarbonization reactions of inferior heavy oil.

[0006] The preparation method of the heavy oil hydrodenitrification and decarbonization catalyst of the present invention includes the following:

[0007] (1) Pseudo-boehmite powder, boron-containing micron-sized spherical activated carbon and water are mixed into a slurry, then the solid and liquid are separated, the solid material is dried, then kneaded, shaped and dried, and then calcined under an inert atmosphere to obtain an alumina carrier precursor. Then boron is loaded and decarburized at the same time to obtain a boron-modified alumina carrier precursor.

[0008] (2) The boron-modified alumina support precursor and propylene oxide aqueous solution are added to a closed high-pressure reactor and reacted at 60-100℃ for 1-4 hours. Then the temperature is raised to 110-180℃ and reacted for 2-6 hours. After solid-liquid separation, the solid material is dried and calcined to obtain the alumina support. Then the hydrogen active component is loaded to obtain the catalyst product.

[0009] In the method of this invention, the preparation method of boron-containing micron-sized spherical activated carbon in step (1) involves impregnating the micron-sized spherical activated carbon with a boric acid solution, followed by drying. The mass concentration of the boric acid solution, calculated as elemental boron, is 0.5%-1.5%, and the solution volume is sufficient to saturate the micron-sized spherical activated carbon with adsorption. The impregnation time is 1-5 hours, and the drying process is generally carried out at 120-180℃ for 1-4 hours. The diameter of the micron-sized spherical activated carbon is 1-3 micrometers, and this micron-sized spherical activated carbon can be prepared by existing methods or purchased.

[0010] In the method of the present invention, the mass ratio of boron-containing micron-sized spherical activated carbon to pseudoboehmite in step (1) is 1:19-1:32, and the amount of deionized water added is such that the liquid-solid mass ratio in the slurry is 5:1-10:1.

[0011] In the method of this invention, the mixing and molding in step (1) are carried out using conventional methods in the art. During molding, an extrusion aid and a binder are added as needed. The extrusion aid is guar gum powder, and the amount added is 0.1wt%-0.5wt% of the final alumina carrier weight. The binder is one or more of hydrochloric acid, nitric acid, sulfuric acid, acetic acid, oxalic acid, etc., and the amount added is 0.1wt%-1.5wt% of the alumina carrier weight, depending on the final molding effect. The drying temperature is 100-160℃, and the drying time is 4-10 hours.

[0012] In the method of the present invention, the inert atmosphere in step (1) is one or more of nitrogen or inert gas; the calcination conditions are: calcination temperature of 450-700℃ and calcination time of 4-6 hours.

[0013] In the method of this invention, the boron loading process in step (1) involves impregnating the alumina carrier precursor with a boric acid aqueous solution. The boron content in the solution, calculated as elemental boron, is 2%-4.5%, and the solution volume is sufficient to completely submerge the alumina carrier precursor. The impregnation time is 1-4 hours. The impregnated material is dried and calcined to obtain the boron-modified alumina carrier precursor. The drying temperature is 100-160℃, and the drying time is 4-10 hours. The calcination temperature is 450-700℃, preferably 450-600℃, and the calcination time is 4-6 hours. The calcination is carried out in an oxygen-containing atmosphere, preferably air. Carbon removal is performed simultaneously during the calcination process.

[0014] In the method of the present invention, the concentration of the propylene oxide aqueous solution in step (2) is 2.5wt%-12wt%, preferably 4wt%-8wt%, and the mass ratio of the propylene oxide aqueous solution to the boron-modified alumina carrier precursor is 3:1-10:1, preferably 4:1-8:1.

[0015] In the method of the present invention, the drying temperature in step (2) is 100-160℃ and the drying time is 2-8 hours; the calcination temperature is 500-750℃ and the calcination time is 4-6 hours, and the calcination is carried out in an oxygen-containing atmosphere, preferably in an air atmosphere.

[0016] In the method of this invention, the loading of the hydrogenation active component in step (2) is carried out by impregnation. The impregnation solution for the hydrogenation active component is a solution containing Group VIB and Group VIII metals. The Group VIB metals are selected from one or more of W and Mo, and the Group VIII metals are selected from one or more of Co and Ni. The content of the Group VIB metals in the impregnation solution, calculated as metal oxides, is 12.5%-28.5 g / 100 mL, and the content of the Group VIII metals, calculated as metal oxides, is 3.0%-6.5 g / 100 mL. The impregnated material is dried and calcined to obtain the catalyst. The drying temperature is 100-160℃, the drying time is 2-8 hours, and the calcination temperature is 450-550℃, the calcination time is 4-6 hours.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] (1) In this invention, boron-containing micron-sized spherical activated carbon and boehmite are first formed. The boehmite is then calcined under an inert atmosphere to transform into alumina, while the spherical activated carbon is retained to provide support. When boron is loaded again, some alumina particles on the surface of the alumina carrier pores are dissolved and removed when the boric acid solution is impregnated, improving the permeability of the corresponding pores. The alumina at the activated carbon sites is protected, which is beneficial for the growth of worm-like alumina during hydrothermal treatment. Since the boric acid solution is weakly acidic, it does not significantly damage the specific surface area and pore volume of the carrier while improving the permeability of the carrier pores. During the calcination of the boron-loaded material, the activated carbon is oxidized and removed, and micron-sized pores are formed at the corresponding positions. The boron oxides formed interact with the alumina surface at the pores, increasing the surface Brønsted acid content without significantly reducing the surface L acid content.

[0019] (2) The boron-modified alumina support precursor is subjected to stepwise sealed heat treatment in propylene oxide solution. Worm-shaped alumina is grown in situ on the surface of the precursor and in the micron-sized cavity. The worm-shaped particles on the surface accumulate to form open channels of 30-100 nm that facilitate the diffusion of reactant molecules. The worm-shaped alumina grains in the micron-sized cavity accumulate to form channels of 30-50 nm. This channel structure reduces the diffusion resistance of large molecular reactants such as polycyclic aromatic hydrocarbons on the one hand, and reduces the blockage of catalyst pores caused by the deposition of carbon deposits and metal sulfides during the reaction process on the other hand. It promotes the diffusion of reactant molecules into the interior of the catalyst pores and into the active center, so that the catalyst has high denitrification and decarbonization activity in the process of hydrotreating inferior heavy oil. Attached Figure Description

[0020] Figure 1 is a SEM image of the alumina support prepared in Example 1.

[0021] Figure 2 This is a SEM image of the alumina support prepared in Comparative Example 2. Detailed Implementation

[0022] The technical solution 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. In the present invention, wt% represents mass fraction.

[0023] The microstructure of the alumina support was characterized using scanning electron microscopy. The specific operation was as follows: The microstructure of the support was characterized using a JSM-7500F scanning electron microscope with an accelerating voltage of 5KV, an accelerating current of 20µA, and a working distance of 8mm.

[0024] Preparation of micron-sized spherical activated carbon:

[0025] The micron-sized spherical activated carbon used in this invention is prepared according to the method described in the literature: Dai Linlin, Li Wei, Wu Qiong, et al. Preparation of micron-sized spherical activated carbon by hydrothermal carbonization-CO2 activation of carboxymethyl cellulose [J]. Chemistry and Industry of Forest Products, 2015, 35(4): 21-27. The diameter of the prepared micron-sized spherical activated carbon is 1-3 microns. Example 1

[0026] (1) Weigh 100g of the above micron-sized spherical activated carbon, impregnate the activated carbon with a boric acid solution with a boron mass concentration of 0.9% for 2 hours, filter the material after impregnation, and dry it at 175℃ for 3 hours to obtain boron-containing micron-sized spherical activated carbon.

[0027] (2) Weigh 500g of borosilicate and 18g of boron-containing micron-sized spherical activated carbon from step (1), mix them evenly, then add 3000g of deionized water and stir for 3 hours. After filtration, the mixture is dried at 140℃ for 4 hours. Add 1.5g of guar gum powder to the dried material and mix evenly. Then add an appropriate amount of 0.5% acetic acid solution to the mixture and knead evenly. Extrude the mixture into strips and dry the strips at 140℃ for 4 hours. The dried material is first calcined at 500℃ under a nitrogen atmosphere for 5 hours to obtain the alumina carrier precursor.

[0028] (3) Weigh 200g of the alumina carrier precursor from step (2), impregnate the carrier precursor with a boric acid solution with a boron mass concentration of 3.6% for 2 hours, filter the impregnated material, dry it at 140℃ for 6 hours, and calcine the dried material at 500℃ for 5 hours in an air atmosphere to obtain the boron-modified alumina carrier precursor.

[0029] (4) Weigh 100g of the boron-modified alumina carrier precursor from step (3), add 520g of 6.3% propylene oxide aqueous solution, transfer the mixture into a high-pressure reactor, seal it, place the high-pressure reactor in an oven and seal it at 80℃ for 2 hours, then heat it to 135℃ and seal it for 4.5 hours. After treatment, the material is cooled, washed, and filtered. The solid material is dried at 120℃ for 4 hours and calcined at 500℃ for 5 hours to obtain alumina carrier S1.

[0030] (5) Weigh 50 g of the alumina support S1 from step (4), impregnate the alumina support with an impregnation solution of molybdenum oxide concentration of 19.5 g / 100 mL and nickel oxide concentration of 3.9 g / 100 mL, dry the impregnated material at 120 °C for 4 hours, and calcine at 450 °C for 5 hours to obtain the hydrogenation denitrification and decarbonization catalyst Cat-1 of the present invention. The properties of the catalyst are shown in Table 1. Example 2

[0031] Same as Example 1, except that in step (1) the boron concentration in the boric acid solution is 1.2%. In step (2) the amount of boron-containing micron-sized spherical activated carbon added is 20 grams. In step (3) the boron concentration in the boric acid solution is 2.7%. In step (4) the concentration of propylene oxide is 6.6%, the amount of solution used is 610 grams, and the hydrothermal treatment is first carried out at 75°C for 3 hours, and then at 145°C for 3 hours to obtain the hydrogenation denitrification and decarbonization catalyst Cat-2 of this invention. The properties of the catalyst are shown in Table 1. Example 3

[0032] Same as Example 1, except that in step (1) the boron concentration in the boric acid solution is 0.8%. In step (2) the amount of boron-containing micron-sized spherical activated carbon added is 24 grams. In step (3) the boron concentration in the boric acid solution is 4.3%. In step (4) the concentration of propylene oxide is 4.6%, the amount of solution used is 750 grams, and the hydrothermal treatment is first carried out at 60°C for 4 hours, and then at 155°C for 2.5 hours to obtain the hydrogenation denitrification and decarbonization catalyst Cat-3 of this invention. The properties of the catalyst are shown in Table 1. Example 4

[0033] Same as Example 1, except that in step (1), the boron mass concentration in the boric acid solution is 1.4%. In step (2), the amount of boron-containing micron-sized spherical activated carbon added is 16 grams. In step (3), the boron mass concentration in the boric acid solution is 2.2%. In step (4), the concentration of propylene oxide is 7.2%, the amount of solution used is 450 grams, and during hydrothermal treatment, it is first treated at 95°C for 1 hour, and then treated at 125°C for 5 hours to obtain the hydrogenation denitrification and decarbonization catalyst Cat-4 of this invention. The properties of the catalyst are shown in Table 1.

[0034] Comparative Example 1

[0035] Same as Example 1, except that the propylene oxide aqueous solution in step (4) was replaced with an ammonia aqueous solution of the same mass concentration to prepare the comparative hydrogenation denitrification and decarbonization catalyst Cat-5. The properties of the catalyst are shown in Table 1.

[0036] Comparative Example 2

[0037] Same as Example 1, except that the propylene oxide aqueous solution in step (4) was replaced with an ethylene oxide solution of the same concentration to prepare the comparative hydrogenation denitrification and decarbonization catalyst Cat-6. The catalyst properties are shown in Table 1, and the scanning electron microscope image of the outer surface of the support is shown in Table 1. Figure 2 .

[0038] Comparative Example 3

[0039] Same as Example 1, except that the concentration of propylene oxide in step (4) is 1.5%, and the comparative hydrogenation denitrification and decarbonization catalyst Cat-7 is obtained. The properties of the catalyst are shown in Table 1.

[0040] Comparative Example 4

[0041] Same as Example 1, except that step (1) boric acid impregnation of micron-sized spherical activated carbon and step (2) boric acid impregnation of alumina support precursor are missing. Instead, the same amount of boron is added by kneading when the pseudoboehmite is kneaded in step (2) to prepare the comparative hydrogenation denitrification and decarbonization catalyst Cat-8. The properties of the catalyst are shown in Table 1.

[0042] Table 1 Properties of catalysts for hydrodenitrogenation and carbon residue removal

[0043] Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 catalyst Cat-1 Cat-2 Cat-3 Cat-4 Cat-5 Cat-6 Cat-7 Cat-8 <![CDATA[MoO3 content, g / 100g]]> 20.3 20.8 21.1 20.6 20.9 21.1 20.8 20.6 NiO content, g / 100g 3.9 3.8 3.9 4.1 3.7 3.9 4.0 4.1 Boron content of catalyst, wt% 3.8 2.7 4.4 2.5 3.9 3.8 4.0 3.9 Boron content in micron-sized channels, wt% 4.9 4.2 5.6 4.1 4.8 4.9 5.1 3.8 Total acid content, mmol / g 0.48 0.51 0.46 0.52 0.51 0.49 0.49 0.52 B acid content, mmol / g 0.14 0.12 0.13 0.11 0.13 0.14 0.15 0.04 L-acid content, mmol / g 0.34 0.39 0.33 0.41 0.38 0.35 0.34 0.48 Catalyst surface particle morphology worm-like worm-like worm-like worm-like granular granular granular worm-like Catalyst surface worm-like particle coverage, % 93 95 97 92 — — — 94 The catalyst surface is formed by the accumulation of worm-like particles, resulting in pore sizes in nm. 35-95 40-100 45-100 30-90 10-85 10-80 10-95 35-100

[0044] From the data in Table 1 and Figure 1 , 2 As can be seen, compared with the comparative catalyst, the surface particle morphology of the hydrodenitrification and decarbonization catalyst prepared by the method of the present invention is worm-like, the pores formed by the accumulation of worm-like particles are open, and the catalyst has suitable Brønsted acid and Lewis acid content. Example 5

[0045] The hydrodenitrification and decarbonization catalysts Cat-1, Cat-2, Cat-3, and Cat-4 prepared in this invention, and the comparative hydrodecarbonization catalysts Cat-5, Cat-6, Cat-7, and Cat-8 prepared in the same proportion, were respectively loaded into a fixed-bed hydrotreating reactor. Using vacuum residue as feedstock (nitrogen content of 0.48 wt% and carbon residue content of 12.8 wt%), the catalytic performance of the catalysts was evaluated under the following conditions: reaction temperature 370℃, pressure 13.5 MPa, and liquid hourly space velocity (LHSV) 0.45 h⁻¹. -1 The hydrogen-to-oil volume ratio was 750. After 2000 hours of reaction, the content of each impurity in the generated oil was measured, the impurity removal rate was calculated, and the evaluation results are shown in Table 2.

[0046] Table 2 Evaluation results of the catalyst

[0047]

[0048] As can be seen from the results in Table 2, compared with the comparative catalyst, the catalyst prepared by the method of the present invention has higher denitrification and decarbonization activity and higher activity stability.

Claims

1. A method for preparing a catalyst for hydrogenation denitrification and decarbonization of heavy oil, comprising the following steps: (1) mixing boehmite powder, boron-containing micron-sized spherical activated carbon and water into a slurry, then separating the solid and liquid phases, drying the solid phase material, then kneading, molding, drying, and then calcining under an inert atmosphere to obtain an alumina support precursor, then loading boron and simultaneously decarbonizing to obtain a boron-modified alumina support precursor; (2) adding the boron-modified alumina support precursor and propylene oxide aqueous solution into a closed high-pressure reactor, first reacting at 60-100℃ for 1-4 hours, then raising the temperature to 110-180℃ for 2-6 hours; after solid-liquid separation, the solid phase material is dried and calcined to obtain an alumina support, then loading hydrogenation active components to obtain the catalyst product. The boron loading process in step (1) involves impregnating the alumina carrier precursor with a boric acid aqueous solution. The boron content in the solution is 2%-4.5% (based on elemental boron), and the solution volume is sufficient to completely submerge the alumina carrier precursor. The impregnation time is 1-4 hours. The impregnated material is dried and calcined to obtain the boron-modified alumina carrier precursor. The drying temperature is 100-160℃, and the drying time is 4-10 hours. The calcination temperature is 450-700℃, and the calcination time is 4-6 hours. The calcination is carried out in an oxygen-containing atmosphere. The concentration of the propylene oxide aqueous solution in step (2) is 2.5wt%-12wt%. The mass ratio of the propylene oxide aqueous solution to the boron-modified alumina carrier precursor in step (2) is 3:1-10:

1.

2. The method according to claim 1, characterized in that: The preparation method of boron-containing micron-sized spherical activated carbon in step (1) is to impregnate the micron-sized spherical activated carbon with boric acid solution, and then dry the activated carbon. The mass concentration of the boric acid solution is 0.5%-1.5% based on elemental boron, and the amount of solution used is to saturate the micron-sized spherical activated carbon with adsorption. The impregnation time is 1-5 hours, and the drying treatment is carried out at 120-180℃ for 1-4 hours. The diameter of the micron-sized spherical activated carbon is 1-3 microns.

3. The method according to claim 1, characterized in that: In step (1), the mass ratio of boron-containing micron-sized spherical activated carbon to pseudoboehmite is 1:19-1:32, and the amount of deionized water added is such that the liquid-solid mass ratio in the slurry is 5:1-10:

1.

4. The method according to claim 1, characterized in that: The inert atmosphere mentioned in step (1) is one or more of nitrogen or inert gas; the calcination conditions are: calcination temperature of 450-700℃ and calcination time of 4-6 hours.

5. The method according to claim 1, characterized in that: The concentration of the propylene oxide aqueous solution in step (2) is 4wt%-8wt%.

6. The method according to claim 1, characterized in that: In step (2), the mass ratio of propylene oxide aqueous solution to boron-modified alumina carrier precursor is 4:1-8:

1.

7. The method according to claim 1, characterized in that: The drying temperature in step (2) is 100-160℃ and the drying time is 2-8 hours; the calcination temperature is 500-750℃ and the calcination time is 4-6 hours, and the calcination is carried out in an oxygen-containing atmosphere.

8. The method according to claim 1, characterized in that: The loading of the hydrogenation active component in step (2) is carried out by impregnation. The impregnation solution of the hydrogenation active component is a solution containing Group VIB and Group VIII metals. The Group VIB metals are selected from one or more of W and Mo, and the Group VIII metals are selected from one or more of Co and Ni. The content of the Group VIB metals in the impregnation solution, calculated as metal oxides, is 12.5%-28.5 g / 100 mL, and the content of the Group VIII metals, calculated as metal oxides, is 3.0%-6.5 g / 100 mL. The impregnated material is dried and calcined to obtain the catalyst. The drying temperature is 100-160℃, the drying time is 2-8 hours, the calcination temperature is 450-550℃, and the calcination time is 4-6 hours.

9. The application of the catalyst prepared by the method according to any one of claims 1 to 8 in the hydrodenitrification and decarbonization reaction of heavy oil.

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