An alumina material, a hydrogenation catalyst and its preparation method

Abstract

This invention discloses an alumina material, a hydrogenation catalyst, and its preparation method. The alumina material of this invention is a mixed phase of γ-Al₂O₃ and AlOOH, wherein the AlOOH morphology is worm-like and grows in situ on the outer surface of the γ-Al₂O₃ support, with worm-like AlOOH crystals covering 85%-100% of the outer surface of the γ-Al₂O₃ support. The preparation method of the alumina material of this invention includes the following steps: The γ-Al₂O₃ support is placed in a propylene oxide solution and subjected to hydrothermal treatment under sealed conditions: first, hydrothermal treatment at 60-100℃ for 1-4 hours, then hydrothermal treatment at 110-180℃, preferably 120-160℃, for 2-6 hours; the treated material is then dried to obtain the alumina material. The alumina material exhibits a worm-like surface particle morphology and a high content of 8-15nm pores. This alumina material as a support has broad application prospects in heterogeneous catalyst reactions, especially in the field of heavy oil hydrogenation. The hydrogenation catalyst prepared using this support has high hydrodenitrification and desulfurization activity.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of catalyst preparation, and particularly relates to an alumina material, a hydrogenation catalyst and a preparation method thereof. BACKGROUND

[0002] With the aggravation of the trend of crude oil becoming heavier and the development of unconventional oil resources, heavy oil (heavy distillate oil) will become the main object of future petroleum processing. The main characteristics of heavy oil are high content of sulfur, nitrogen, metals and polycyclic aromatic hydrocarbon compounds, which are easy to cause catalyst poisoning and deactivation in the process of heavy oil hydrotreating, thus putting forward higher requirements for hydrotreating catalysts. Sulfur, nitrogen, metals and the like of heavy oil are all in aromatic ring structures, and the hydrogenation removal of nitrogen compounds is the most difficult, so the development of poor heavy distillate oil hydrogenation denitrification catalyst is the key to improving the technical level of heavy oil hydrotreating process.

[0003] CN105983412A discloses a high denitrification performance hydrogenation catalyst and a preparation method thereof. First, a silicon-containing pseudo-boehmite is prepared, a carrier is prepared by adding a phosphorus salt in a peptization process with the silicon-containing pseudo-boehmite as a raw material, and finally an active component is loaded to prepare the catalyst. The catalyst prepared by the method has high pore volume, specific surface area, certain 20-30nm pore channel content and suitable acid properties, but the surface pore channel structure of the catalyst is not conducive to the diffusion of reactant molecules.

[0004] CN111821989A discloses a residue oil hydrogenation denitrification catalyst and a preparation method thereof. The catalyst includes a modified alumina-based carrier, molybdenum and nickel metal components, the modified alumina-based carrier contains tungsten and cobalt metal components, the modified alumina-based carrier includes a main modified alumina and a rod-shaped modified alumina, the main modified alumina is a modified alumina with micron-level pores, and at least part of the rod-shaped modified alumina is distributed on the outer surface of the main modified alumina and in micron-level pores with a pore diameter D of 3-7μm. The surface of the catalyst prepared by the method is a rod-shaped structure, but the firmness of the rod-shaped alumina grown on the surface and the main alumina needs to be further improved. SUMMARY

[0005] In view of the deficiencies in the prior art, the present application provides an alumina material, a hydrogenation catalyst and a preparation method thereof. The surface particles of the alumina material are in a worm-like shape, and the 8-15nm pore channel content is high. The alumina as a carrier has a wide application prospect in the field of multiphase catalyst reaction, especially heavy oil hydrogenation. The hydrogenation catalyst prepared by the carrier has high hydrogenation denitrification and desulfurization activity.

[0006] The alumina material of this invention is a mixed phase of γ-Al₂O₃ and AlOOH, wherein the AlOOH has a worm-like morphology and grows in situ on the outer surface of the γ-Al₂O₃ support. The worm-like AlOOH grains cover 85%-100% of the outer surface of the γ-Al₂O₃ support, where the coverage rate refers to the percentage of the outer surface of the γ-Al₂O₃ support occupied by the worm-like AlOOH particles. The worm-like AlOOH grains have a size of 80-350 nm and are stacked to form open channels of 30-100 nm.

[0007] In the alumina material of this invention, the ratio H of the grain size of the crystal plane corresponding to the AlOOH (120) peak to the grain size of the crystal plane corresponding to the γ-Al2O3 (440) peak is 1.5-2.5, where H=D AlOOH (120) / D γ-Al2O3 (440), where D(120) represents the grain size of the crystal plane corresponding to the AlOOH(120) peak in the XRD spectrum; the 120 peak refers to the characteristic peak with 2θ of 25.5-29.9º in the XRD spectrum; D(440) represents the grain size of the crystal plane corresponding to the γ-Al2O3(440) peak in the XRD spectrum; the 440 peak refers to the characteristic peak with 2θ of 63.6-69.1º in the XRD spectrum.

[0008] The alumina material of this invention has a specific surface area of ​​220-380 m². 2 / g, pore volume is 0.6-1.3mL / g, most probable pore size is 8-15nm, and pores of 8-15nm account for 60%-80% of the total pore volume.

[0009] The method for preparing the alumina material of the present invention includes the following steps: placing a γ-Al2O3 support in a propylene oxide solution and subjecting it to hydrothermal treatment under sealed conditions: firstly, hydrothermal treatment is carried out at 60-100°C for 1-4 hours, and then hydrothermal treatment is carried out at 110-180°C, preferably 120-160°C, for 2-6 hours. The treated material is then dried to obtain the alumina material.

[0010] In the method of this invention, the γ-Al2O3 support mentioned in step (1) can be a commercially available product or prepared according to existing methods. Its shape can be that of a conventional alumina support, such as spherical, with a particle size generally 2-8.0 mm, or cylindrical, clover-shaped, or four-leaf clover-shaped, with a diameter of approximately 0.2-3.0 mm and a length of approximately 3-8.0 mm. For example, the γ-phase alumina support is generally obtained by mixing, molding, drying, and calcining pseudoboehmite. The pseudoboehmite can be prepared by any method. During molding, an extrusion aid and a binder can be added as needed. The extrusion aid is guar gum powder, added at 0.1 wt%-0.5 wt% of the weight of the alumina support. The binder is one or more of hydrochloric acid, nitric acid, sulfuric acid, acetic acid, oxalic acid, etc., added at 0.5 wt%-1.5 wt% of the weight of the alumina support. The drying temperature is 100-160℃, the drying time is 1-8 hours, the calcination temperature is 450-600℃, and the calcination time is 1-8 hours.

[0011] In the method of this 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 γ-Al2O3 support is 3:1-10:1, preferably 4:1-8:1. The sealing heat treatment is carried out in a closed container, preferably an autoclave. The sealing heat treatment is a two-step sealing heat treatment, namely, firstly, sealing heat treatment at 60-100℃ for 1-4 hours, and then treatment at 110-180℃, preferably 120-160℃, for 2-6 hours.

[0012] 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 600-750℃ and the calcination time is 4-6 hours. The calcination is carried out in an oxygen-containing atmosphere, preferably in an air atmosphere.

[0013] The present invention also provides an alumina carrier, which is obtained by calcining the above-mentioned alumina material. The calcination conditions are: the calcination temperature is 450-700℃ and the calcination time is 4-10 hours.

[0014] The present invention also provides a hydrogenation catalyst comprising the aforementioned alumina support or alumina material. The hydrogenation catalyst is obtained by loading the hydrogenation active component onto an alumina support or alumina material.

[0015] The loading can be achieved through impregnation, kneading, or other methods. For example, an alumina support can be impregnated with a hydrogenation active component impregnation solution, and the impregnated material is then dried and calcined to obtain a hydrogenation catalyst. The hydrogenation active component impregnation solution 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 8.5%-22.5 g / 100 mL, and the content of the Group VIII metals, calculated as metal oxides, is 2.5%-6.5 g / 100 mL. The drying temperature 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.

[0016] Compared with existing technologies, this invention has the following advantages: In this invention, the γ-Al₂O₃ support is placed in a propylene oxide solution and subjected to sealed heat treatment. During low-temperature sealed heat treatment, the propylene oxide hydrolyzes to form an alcohol solution, making the solution weakly alkaline. During high-temperature sealed hydrothermal treatment, the surface grains of the γ-Al₂O₃ support grow in situ into worm-like AlOOH particles under alkaline and alcoholic solution conditions. These worm-like AlOOH particles are uniformly and highly cover the support surface, and the particle accumulation forms open channels of 30-100 nm. This channel structure facilitates the diffusion of reactant molecules into the catalyst interior, improving the internal reaction activity of the catalyst. This alumina can be used as a support for heterogeneous catalytic reactions. After calcination, the worm-like AlOOH grains on the support surface undergo a phase transformation to γ-Al₂O₃. The active metal components impregnated on the AlOOH grain surface synergize with the phase transformation process of the AlOOH grains, effectively regulating the interaction between the active metal components and the alumina support, reducing the formation of the nickel-aluminum spinel phase, and giving the catalyst high denitrification and desulfurization activity while also exhibiting high activity stability. Attached Figure Description

[0017] Figure 1 shows the XRD patterns of the alumina support precursor (A) and alumina support (B) prepared in Example 1.

[0018] Figure 2 This is a low-magnification SEM image of the alumina carrier surface prepared in Example 1.

[0019] Figure 3 This is a high-magnification SEM image of the alumina carrier surface prepared in Example 1.

[0020] Figure 4 Low-magnification SEM image of the alumina support surface prepared in Comparative Example 2. Detailed Implementation

[0021] 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.

[0022] BET Method: The pore structure of the carriers in the examples and comparative examples was characterized using N2 physical adsorption-desorption. The specific procedure was as follows: The pore structure of the samples was characterized using an ASAP-2420 N2 physical adsorption-desorption instrument. A small amount of sample was vacuum-treated at 300℃ for 3-4 hours, and finally, the product was placed under liquid nitrogen cryogenic conditions (-200℃) for nitrogen adsorption-desorption testing. The specific surface area was obtained according to the BET equation, and the pore volume and pore diameter distribution below 30nm were obtained according to the BJH model.

[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. Example 1

[0024] (1) Weigh 500g of boehmite, add 3g of guar gum powder and mix evenly. Then add an appropriate amount of 0.5% acetic acid solution to the mixture and knead evenly. Extrude into strips and dry the strips at 120℃ for 5 hours and calcine at 600℃ for 5 hours to obtain the alumina support precursor. The XRD pattern of the support is shown in the figure. Figure 1 The A curve in the diagram.

[0025] (2) Weigh 100 g of the alumina carrier precursor from step (1), add 660 g of a 5.3% propylene oxide aqueous solution, transfer the mixture into an autoclave, seal it, place the autoclave in an oven and seal it at 75°C for 2.5 hours, then raise the temperature to 130°C and seal it for 5 hours. After treatment, the material is cooled, washed, and filtered. The solid material is dried at 130°C for 6 hours to obtain alumina carrier S1. The XRD pattern of this carrier is shown in [reference needed]. Figure 1 The B-curve and the properties of the support are shown in Table 1. The scanning electron microscope image of the outer surface of the support is shown in [reference needed]. Figure 2 , Figure 3 .

[0026] (3) Weigh 50 g of the alumina support S1 from step (2), and impregnate the alumina support with an impregnation solution of molybdenum oxide concentration of 18.3 g / 100 mL and nickel oxide concentration of 4.9 g / 100 mL by saturation impregnation. After impregnation, dry the material at 120 °C for 6 hours and calcine at 500 °C for 5 hours to obtain the hydrogenation denitrification catalyst Cat-1. Example 2

[0027] Same as Example 1, except that in step (2) the concentration of propylene oxide is 6.8% and the amount of solution is 560 grams. During hydrothermal treatment, it is first treated at 80°C for 2 hours and then at 145°C for 4 hours to obtain the alumina support S2 and the hydrodenitrification catalyst Cat-2 of the present invention. The properties of the support are shown in Table 1. Example 3

[0028] Same as Example 1, except that in step (2), the concentration of propylene oxide is 4.6%, the amount of solution is 720 grams, and the hydrothermal treatment is first performed at 60°C for 3.5 hours, and then at 160°C for 2.5 hours to obtain the alumina support S3 and the hydrodenitrification catalyst Cat-3 of the present invention. The properties of the support are shown in Table 1. Example 4

[0029] Same as Example 1, except that in step (2), the concentration of propylene oxide is 7.5% and the amount of solution is 510 grams. During hydrothermal treatment, the solution is first treated at 90°C for 1.5 hours and then at 125°C for 5.5 hours to obtain the alumina support S4 and the hydrodenitrification catalyst Cat-4 of the present invention. The properties of the support are shown in Table 1.

[0030] Comparative Example 1

[0031] Same as Example 1, except that in step (2) the aqueous solution of propylene oxide was replaced with an aqueous solution of ammonia of the same mass concentration to prepare comparative alumina support S5 and comparative hydrodenitrification catalyst Cat-5. The properties of the alumina support are shown in Table 1.

[0032] Comparative Example 2

[0033] Same as Example 1, except that in step (2), the propylene oxide aqueous solution was replaced with an ethylene oxide solution of the same concentration to prepare the comparative alumina support S6 and the comparative hydrodenitrification catalyst Cat-6. The properties of the alumina support are shown in Table 1, and the scanning electron microscope images of the outer surface of the support are shown in Table 2. Figure 4 .

[0034] Comparative Example 3

[0035] Same as Example 1, except that the concentration of propylene oxide in step (2) is 1.5%, and comparative alumina support S7 and comparative hydrodenitrification catalyst Cat-7 are prepared. The properties of the alumina support are shown in Table 1.

[0036] Comparative Example 4

[0037] Same as Example 1, except that step (2) hydrothermal treatment is a one-step hydrothermal treatment with a heat treatment temperature of 70°C and a treatment time of 14 hours, to obtain comparative alumina support S8 and comparative hydrodenitrification catalyst Cat-8. The properties of the alumina support are shown in Table 1, and the hydrodemetallization catalyst is shown in Table 3.

[0038] Table 1 Properties of Alumina Supports

[0039] Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Support S1 S2 S3 S4 S5 S6 S7 S8 Specific surface area, m 2 / g]] 269 284 277 292 220 232 247 239 Pore volume, mL / g 0.95 0.93 0.92 0.94 0.83 0.85 0.88 0.87 8-15 nm pore content, % 76.3 73.2 75.5 74.8 53.2 51.5 53.4 52.6 Surface worm-like particle crystallite size, nm 95-340 85-345 80-330 85-340 — — — — Surface worm-like particle coverage, % 95 93 97 98 — — — — Support surface pore size, nm 35-95 35-100 30-95 30-100 10-70 15-75 10-65 10-80 H 1.9 1.7 2.1 2.3 — — — —

[0040] From the data in Table 1 and Figures 2-4 As can be seen, compared with the comparative alumina support, the alumina support prepared by the method of the present invention has a higher 8-15nm pore content, and the alumina support surface has a high macropore content and open pores. Example 5

[0041] The hydrodenitrification catalysts Cat-1, Cat-2, Cat-3, and Cat-4 prepared according to this invention, and the comparative hydrodenitrification catalysts Cat-5, Cat-6, Cat-7, and Cat-8 prepared according to the present invention, were respectively loaded into a fixed-bed hydrotreating reactor. Using vacuum residue as feedstock (the feedstock contained 3.68 wt% sulfur, 0.34 wt% nitrogen, and 16.4 wt% carbon residue), the catalytic performance of the catalysts was evaluated under the following conditions: reaction temperature 390℃, pressure 14.8 MPa, and liquid hourly space velocity 0.45 h⁻¹. -1 The hydrogen-to-oil volume ratio was 800. 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.

[0042] Table 2 Evaluation results of the catalyst

[0043]

[0044] As can be seen from the results in Table 2, compared with the comparative hydrodenitrification catalyst, the hydrodenitrification catalyst prepared by the method of the present invention has higher desulfurization and denitrification activity and higher activity stability.

Claims

1. An alumina material characterized by: The alumina material is a mixed crystal phase of γ-Al2O3 and AlOOH, wherein the AlOOH has a worm-like morphology and is in-situ grown on the outer surface of the γ-Al2O3 carrier, the coverage of the worm-like AlOOH grains on the outer surface of the γ-Al2O3 carrier is 85%-100%, the worm-like AlOOH grains are stacked on the outer surface of the γ-Al2O3 carrier to form 30-100nm pores, the ratio H of the grain size of the crystal face corresponding to the AlOOH (120) peak to the grain size of the crystal face corresponding to the γ-Al2O3 (440) peak is 1.5-2.5, H=D AlOOH (120) / D γ-Al2O3 (440), wherein D(120) represents the grain size of the crystal face corresponding to the AlOOH (120) peak in the XRD spectrum, the 120 peak refers to the characteristic peak with 2θ of 25.5-29.9° in the XRD spectrum, D(440) represents the grain size of the crystal face corresponding to the γ-Al2O3 (440) peak in the XRD spectrum, the 440 peak refers to the characteristic peak with 2θ of 63.6-69.1° in the XRD spectrum, and the preparation method of the alumina material comprises the following steps: placing a γ-Al2O3 carrier in a propylene oxide solution under a sealed condition for hydrothermal treatment, first hydrothermal treatment at 60-100°C for 1-4 hours, then hydrothermal treatment at 110-180°C for 2-6 hours, drying the treated material to obtain the alumina material, the concentration of the propylene oxide aqueous solution is 2.5wt%-12wt%, the mass ratio of the propylene oxide aqueous solution to the γ-Al2O3 carrier is 3:1-10:1, the drying temperature is 100-160°C, and the drying time is 2-8 hours.

2. The aluminum oxide material of claim 1, wherein: The worm-like AlOOH has a grain size of 80-350 nm.

3. The aluminum oxide material of claim 1, wherein: The alumina material has a specific surface area of 220-380 m 2 / g, a pore volume of 0.6-1.3 mL / g, a most probable pore diameter of 8-15 nm, and 60-80% of the total pore volume in pores of 8-15 nm.

4. A process for the preparation of an alumina material as claimed in any one of claims 1 to 3, characterised in that The method comprises the following steps: placing a γ-Al2O3 carrier in a propylene oxide solution under a closed condition and performing hydrothermal treatment, first hydrothermal treatment at 60-100 ℃ for 1-4 hours, then hydrothermal treatment at 110-180 ℃ for 2-6 hours, and drying the treated material to obtain an alumina material.

5. The method of claim 4, wherein: The propylene oxide aqueous solution has a concentration of 2.5 wt%-12 wt%, and the mass ratio of the propylene oxide aqueous solution to the γ-Al2O3 carrier is 3:1-10:

1.

6. The method of claim 4, wherein: The drying temperature is 100-160 ℃, and the drying time is 2-8 hours.

7. Use of the alumina material of any one of claims 1-3 in a heterogeneous catalytic reaction.

8. An alumina support, characterized by: The alumina material is obtained by calcining the alumina material of any one of claims 1-3.

9. The alumina support of claim 8, wherein: The calcination is performed at a calcination temperature of 450-700 ℃ for 4-10 hours.

10. A hydrogenation catalyst comprising the alumina carrier of claim 8 and / or the alumina material of any one of claims 1-3.

11. The hydrogenation catalyst of claim 10, wherein: The hydrogenation catalyst is obtained by loading a hydrogenation active component on the alumina carrier or the alumina material.

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