A method for preparing a carbon-containing hydrodemetallization catalyst

Abstract

The application discloses a preparation method of a carbon-containing hydrodemetallization catalyst, and comprises the following steps: (1) roasting, crushing and screening aluminum nitrate, mixing the screened material with an aqueous solution containing propylene oxide and polyhydric alcohol, and hydrothermally treating the mixture, then filtering, washing and drying the treated material to obtain carbon-modified sheet-like pseudoboehmite P1; (2) mixing the pseudoboehmite P1 with pseudoboehmite P2 to obtain a mixture H0, and rolling the mixture to form an alumina carrier precursor S0; (3) mixing the S0 with the carbon-modified sheet-like pseudoboehmite prepared in the step (1), and continuously rolling the mixture to form a molding material, then drying and roasting the molding material to obtain an alumina carrier; and (4) impregnating the carrier with an active component impregnation solution, and drying and roasting the carrier to obtain a hydrodemetallization catalyst. The hydrodemetallization catalyst prepared by the method has high catalytic activity sites, large pore channels, high metal impurity and carbon deposition resistance, and high demetallization activity and stability in a residual oil hydroprocessing process.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of catalyst preparation, and particularly relates to a preparation method of a carbon-containing hydrodemetallization catalyst. BACKGROUND

[0002] With the increasing seriousness of the heavy and poor quality of crude oil, oil refining enterprises are faced with the problem of processing and utilizing a large amount of heavy and residual oil. Heavy and residual oil molecules have a complex three-dimensional structure. In the process of catalytic hydrogenation, heavy oil macromolecules are adsorbed and deposited on the surface or pore of the catalyst, which increases the internal diffusion resistance of the reaction and causes the apparent activity of the catalyst to decrease. At the same time, heavy and residual oil contains a large amount of coke precursors, which will generate coke and deposit in the pores under certain conditions, causing the active center of the catalyst to be poisoned. Therefore, the catalyst with large pore volume and large pore diameter has strong metal and carbon capacity, which can slow down the deactivation of the catalyst and prolong the operation cycle of the catalyst.

[0003] Alumina is a commonly used catalyst carrier in the field of petroleum chemical industry. It has been widely used and has the largest amount of use because of its good mechanical stability, easy control of specific surface area and pore structure, and low cost. However, the pore of the conventional alumina carrier is small. In order to meet the needs of heavy and residual oil hydrogenation treatment, the method of "pore expansion" is usually used to improve the pore structure of the alumina carrier. On the other hand, in the calcination process, the active metal components are easily reacted with the alumina carrier to form a strong M-O-Al bond, which causes the active components to form spinel phase and lose activity, or makes the active components unable to be completely sulfided, thereby reducing the activity of the catalyst.

[0004] CN201510191156.7 discloses a heavy oil hydrogenation catalyst and a preparation method thereof. The catalyst comprises an alumina carrier composed of flaky polycrystalline γ-alumina and a hydrogenation active metal. The preparation method of the catalyst is as follows: flaky γ-polycrystalline alumina raw powder is added to a binder and a extrusion aid, kneaded, formed, dried and calcined to obtain an alumina carrier, and the active metal is loaded on the obtained alumina carrier by using a conventional method. The preparation method of the flaky γ-polycrystalline alumina comprises the following steps: (1) mixing inorganic aluminum salt, low-carbon alcohol and / or water, and low-carbon alkylene oxide uniformly to form a gel, and then aging the gel; (2) soaking the gel obtained in step (1) with 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, and drying to obtain flaky γ-polycrystalline alumina raw powder. The invention adjusts the pore structure of the carrier by adding flaky γ-polycrystalline alumina to the alumina carrier, but the preparation process of the flaky γ-polycrystalline alumina is relatively complex.

[0005] CN104646008A discloses a poor quality heavy oil hydrodesulfurization and demetallization catalyst and a preparation method thereof. The catalyst uses alumina as a carrier, and VIB and VIII elements, particularly Ni-Mo, as active components. The catalyst has a pore volume of 0.61-0.70 mL / g, a specific surface area of 155-200 m 2 / g, and an average pore diameter of 13.0-18.0 nm. The preparation method is to treat the carrier particles after molding and calcination with acid solutions with continuously increasing concentrations. Although this method can make the average pore diameter of the final catalyst gradually increase from the center to the outer surface of the catalyst particles to some extent, it is difficult to form larger pores on the surface of the carrier by this treatment.

[0006] CN105582947A discloses a preparation method of a carbon-containing residue oil hydrodemetallization catalyst. The preparation method includes the following steps: (1) preparing at least two aqueous solutions of polyols and / or monosaccharides with different concentrations, and spraying the solutions on an alumina carrier in the order of decreasing concentration, so that the concentrations of the polyols and / or monosaccharides form a gradient distribution from low to high from the outside to the inside of the carrier; (2) performing hydrothermal carbonization treatment on the impregnated alumina carrier in a sealed container, and performing drying treatment; (3) impregnating the carrier of step (2) with an impregnation solution containing active metal components, and placing the impregnated wet material in a pressure-resistant container, and introducing ammonia gas for step-by-step treatment; and (4) drying the material treated in step (3), and performing oxygen-free high-temperature treatment to obtain a catalyst product. This method adjusts the strong interaction between the active metal and the carrier by carbon, and improves the activity of the catalyst, but the pore structure of the catalyst is not conducive to the diffusion of macromolecular reactants into the interior of the catalyst. SUMMARY

[0007] In view of the deficiencies in the prior art, the present application provides a preparation method of a carbon-containing hydrodemetallization catalyst. The hydrodemetallization catalyst prepared by the method has high catalytic activity sites and large pores, strong metal impurity and carbon deposition resistance, and high demetallization activity and stability in the residue oil hydroprocessing process.

[0008] The preparation method of the carbon-containing hydrodemetallization catalyst of the present application includes the following steps:

[0009] (1) calcining aluminum nitrate, crushing and sieving the calcined material, mixing the sieved material with an aqueous solution containing propylene oxide and polyols, and then performing hydrothermal treatment, filtering, washing, and drying the treated material to obtain carbon-modified sheet-like pseudoboehmite P1;

[0010] (2) mixing the carbon-modified sheet-like pseudoboehmite P1 and pseudoboehmite P2 to obtain a mixture H0, and rolling the mixture to form a spherical shape to obtain an alumina carrier precursor S0;

[0011] (3) mixing the alumina carrier precursor S0 of step (2) with the carbon modified sheet-like boehmite P1, continuing the ball-rolling shaping, and drying and calcining the shaped material to obtain an alumina carrier;

[0012] (4) impregnating the carrier of step (3) with an active component impregnation solution, and drying and calcining to obtain a hydrodemetallization catalyst.

[0013] In the method, the calcination temperature of the aluminum nitrate in step (1) is 450-650℃, the calcination time is 4-8 hours, and the particle size after crushing is greater than 100 mesh.

[0014] In the method, the concentration of the propylene oxide solution in the water solution containing propylene oxide and polyhydric alcohol in step (1) is 2.5wt%-12wt%, preferably 4wt%-8wt%, and the mass ratio of the mixed solution to the powder material is 3:1-10:1, preferably 4:1-8:1.

[0015] In the method, the polyhydric alcohol in step (1) is one or a mixture of several of xylitol, sorbitol, mannitol and arabitol, and the concentration of the polyhydric alcohol in the water solution containing propylene oxide and polyhydric alcohol is 10wt%-20wt%.

[0016] In the method, the sealing hydrothermal treatment in step (1) is carried out in a sealed container, preferably an autoclave, the hydrothermal treatment temperature is 110-180℃, preferably 120-160℃, the treatment time is 4-8 hours, and the pressure in the sealed container during the hydrothermal treatment is autogenous pressure. After the treatment, the material is filtered, washed and dried, and the drying temperature is generally 80-160℃ and the drying time is 4-8 hours.

[0017] In the method, the particle morphology of the boehmite P2 in step (2) is generally granular, which can be a commercially available product or a boehmite prepared by methods such as acid precipitation, alkali precipitation and alcohol aluminum hydrolysis, and is preferably a boehmite with a pore diameter greater than 10nm.

[0018] In the method, the mass ratio of the carbon modified sheet-like boehmite P1 to the boehmite P2 in step (2) is 1:4-2:3. The ball-rolling shaping is carried out in a rotary table shaper, and the operating conditions of the rotary table shaper are as follows: the inclination angle of the rotary table is 40-70º, and the rotation speed of the rotary table is 10-30rpm; the shaping time of the material in the rotary table is 10-120min. The radius of the alumina carrier precursor S0 is 0.4r-0.8r, and r is the radius of the alumina carrier. A water solution containing a glue solvent is sprayed into the material during the ball-rolling shaping; the water solution containing the glue solvent is one or a mixture of several of a water solution of nitric acid, phosphoric acid, oxalic acid and acetic acid, and the mass concentration of the solution is 1%-3%, preferably a water solution of acetic acid.

[0019] In the method, the rolling ball forming in step (3) is carried out in a rotary table forming machine, and the rotary table forming machine is operated under the conditions that the inclination angle of the rotary table is 40-70° and the rotary speed of the rotary table is 10-30 rpm; the forming time of the material in the rotary table is 10-120 min. A water solution containing a glue solvent is sprayed into the material during the rolling ball forming; the water solution containing the glue solvent is one or a mixture of several of water solutions of nitric acid, phosphoric acid, oxalic acid and acetic acid, and the mass concentration of the solution is 1%-3%, and preferably the water solution of acetic acid.

[0020] In the method, the drying temperature in step (3) is 60-180 ℃, and the drying time is 1-8 hours, preferably 2-6 hours; the calcination is carried out under the protection of an inert atmosphere, preferably under the protection of a nitrogen atmosphere, the temperature is 350-800 ℃, preferably 550-750 ℃, and the calcination time is 2-6 hours.

[0021] In the method, the active component impregnation solution in step (4) is a solution containing a Group VIB metal and a Group VIII metal. The Group VIB metal is Mo or W, and preferably Mo, and the Group VIII metal is Ni or Co, and preferably Ni; the content of the Group VIB metal is 5.5-12.5 g / 100 mL as calculated in terms of the oxide, and the content of the Group VIII metal is 0.5-4.5 g / 100 mL as calculated in terms of the oxide; the active component impregnation solution can be an ammonia solution, an aqueous solution or a phosphoric acid solution of the Group VIB metal and the Group VIII metal, and preferably a phosphoric acid solution containing the Group VIB metal and the Group VIII metal; the drying and calcination conditions are well known to those skilled in the art, and are generally as follows: the drying temperature is 100-160 ℃, and the drying time is 6-10 hours; the calcination is carried out in an inert atmosphere, preferably nitrogen, the calcination temperature is 400-550 ℃, and the calcination time is 2-6 hours.

[0022] The carbon-containing hydrodemetallization catalyst prepared by the method has a carbon content of 1%-5% by weight of the catalyst, a molybdenum oxide content of 5%-10%, a nickel oxide content of 1.3%-3%, and the rest is an alumina carrier.

[0023] The carbon-containing hydrodemetallization catalyst prepared by the method has a specific surface area of 160-280 m 2 / g, a pore volume of 0.8-1.0 mL / g, a content of pores with a diameter of 10-20 nm accounting for 35%-55% of the mesopore volume, a content of pores with a diameter of 50-100 nm accounting for 12.5%-25% of the total pore volume, and a content of pores with a diameter greater than 100 nm accounting for 10%-20% of the total pore volume.

[0024] The application of the carbon-containing hydrogen demetallization catalyst prepared by the method in a residual oil hydroprocessing process.

[0025] Compared with the prior art, the application has the following advantages:

[0026] (1) The aluminum oxide compound obtained by calcining aluminum nitrate is placed in a mixed solution of propylene oxide and polyol for hydrothermal treatment to prepare carbon-modified sheet-like pseudoboehmite. During the hydrothermal treatment, the aluminum oxide compound undergoes rehydration in the weak alkaline solution to form sheet-like pseudoboehmite. The preparation process of the sheet-like pseudoboehmite is simple, and the acid-base neutralization and gelation process in the conventional technology is omitted. During the rehydration process, the polyol in the solution uniformly adsorbs the aluminum oxide compound through hydrogen bonding between hydroxyl groups, and the carbon-modified sheet-like pseudoboehmite is generated in one step. The polyol makes the carbon-modified sheet-like pseudoboehmite structure more regular and uniform in morphology. The sheet-like pseudoboehmite grains form a large number of 50-150 nm pore channel structures. The pore channel structure is firm and not easy to collapse, and the use of the pseudoboehmite as a raw material can effectively ensure the macropore content of the alumina carrier in the later stage.

[0027] (2) During the molding of the alumina carrier, the content of the carbon-modified sheet-like pseudoboehmite in the mixed material is adjusted to make the final carrier pore channel have a core-shell structure distribution, i.e., the shell layer pore channel has a larger pore size, the pore channel is open, and the macropore content is high, and the core layer is less. Due to the carbon modification treatment of the sheet-like pseudoboehmite, the active metal components in the macropore formed by the accumulation of sheet-like alumina particles in the finally prepared hydrogen demetallization catalyst are suitable for interaction with the carrier, and the active metal oxides in this region are more easily sulfided, and the hydrogen demetallization activity is high. At the same time, the high catalytic active sites of the catalyst match well with the pore channel structure, which is beneficial to the diffusion of reactants and the strong metal deposition resistance of the catalyst, so that the catalyst has good activity stability. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is an SEM image of the carbon-modified sheet-like pseudoboehmite P1-1 prepared in Example 1.

[0029] Figure 2 is an SEM image of the material P1-6 prepared in Comparative Example 3. IMPLEMENTATION

[0030] The technical solutions and technical effects of the application will be further illustrated below in combination with examples, but are not limited to the following examples. In the application, wt% represents mass fraction.

[0031] BET method: The pore structure of the support of the examples and the comparative examples was characterized by N2 physical adsorption-desorption, and the specific operation was as follows: an ASAP-2420 type N2 physical adsorption-desorption instrument was used to characterize the pore structure of the sample. A small amount of sample was vacuum treated at 300°C for 3-4 hours, and finally the product was placed in liquid nitrogen at low temperature (-200°C) for nitrogen adsorption-desorption test. The specific surface area was obtained according to the BET equation, and the distribution rate of the pore volume and the pore diameter below 30 nm was obtained according to the BJH model.

[0032] The microstructure of the alumina support was characterized by scanning electron microscopy, and the specific operation was as follows: a JSM-7500F scanning electron microscope was used to characterize the microstructure of the support, with an acceleration voltage of 5KV, an acceleration current of 20µA, and a working distance of 8mm.

[0033] X-ray diffraction (XRD) analysis was performed on a D / max-2500 type full-automatic rotating target X-ray diffractometer produced by Japan Science Corporation. A Cu target, a Kα radiation source, a graphite monochromator, a tube voltage of 40kV, and a tube current of 80mA were used.

[0034] Mercury intrusion method: The pore diameter distribution of the support of the examples and the comparative examples was characterized by a mercury intrusion porosimeter, and the specific operation was as follows: an American Mac AutoPore9500 type full-automatic mercury intrusion porosimeter was used to characterize the pore distribution of the sample. After the sample was dried and weighed, it was loaded into the dilatometer and degassed for 30 minutes under the vacuum condition given by the instrument, and then mercury was loaded. Subsequently, the dilatometer was placed in a high-pressure kettle, and the exhaust was performed. Then, the pressure was increased and the pressure was decreased. The mercury contact angle was 130º, the mercury interfacial tension was 0.485N.cm -1 , and the distribution rate of the pore diameter above 100nm was measured by the mercury intrusion method.

[0035] Most probable pore diameter determination: the pore diameter distribution curve was obtained with the material pore diameter as the horizontal coordinate and the change rate of the pore volume with the pore diameter as the vertical coordinate, and the peak value in the curve was the most probable pore diameter.

[0036] The content of Ni and V in the oil product was determined by the standard method of GB / T 34099-2017.

[0037] The V+Ni removal rate% = (the metal V+Ni content of the raw oil - the metal V+Ni content of the product) / the metal V+Ni content of the raw oil × 100%.

[0038] Relative metal removal rate: the relative metal removal rate of a certain catalyst was defined as 100%, and the impurity removal rate of other catalysts was defined as the relative impurity removal rate. Example 1

[0039] (1) A proper amount of aluminum nitrate was placed in a crucible and calcined at 500°C for 5.5 hours. The calcined material was ground and sieved to obtain an aluminum nitrate support with a particle size of 0.125-0.250mm.

[0040] The particles above 200 mesh are screened out. 100 g of the screened particles is added with 610 g of a mixed solution with a propylene oxide concentration of 5.5 wt% and a xylitol concentration of 15 wt%, and is stirred magnetically for 30 minutes. Then the mixture is transferred into an autoclave for sealing and heating at 145 ℃ for 5.3 hours. After cooling, the solid material is filtered, washed, and dried at 120 ℃ for 4 hours to prepare the carbon-modified tabular pseudoboehmite P1-1. The microstructure of the sample is observed by scanning electron microscopy to be tabular grain accumulation, and the scanning electron microscopy image is shown in Figure 1 .

[0041] (2) 100 g of the carbon-modified tabular pseudoboehmite P1-1 prepared in step (1) is mixed with 235

[0042] g of pseudoboehmite P2 (aluminum sulfate-sodium metaaluminate method, most probable pore size 15 nm) to prepare a mixture. The mixture is placed in a rotary table forming machine for mixing, the inclination angle of the rotary table is adjusted to 45°, and the rotary speed of the rotary table is adjusted to 17 rpm. A 1% acetic acid aqueous solution is sprayed onto the mixture in the rotary table by a sprayer, and after mixing and contacting, the forming time of the mixture in the rotary table is 50 min to obtain an alumina carrier precursor S0.

[0043] (3) The carbon-modified tabular pseudoboehmite P1-1 prepared in step (1) and the alumina carrier precursor S0 prepared in step (2) are placed in a rotary table forming machine for mixing, the inclination angle of the rotary table is adjusted to 35°, and the rotary speed of the rotary table is adjusted to 10 rpm. A 1.3% acetic acid aqueous solution is sprayed onto the mixture in the rotary table by a sprayer, and after mixing and contacting, the forming time of the mixture in the rotary table is 60 min. The obtained mixture is dried at 120 ℃ for 4 h and calcined at 700 ℃ in a nitrogen atmosphere for 4 h to obtain a carbon-containing alumina carrier.

[0044] (4) 50 g of the carbon-containing alumina carrier prepared in step (3) is impregnated with an Mo-Ni-P impregnating solution with a molybdenum oxide concentration of 8.5 g / 100 mL and a nickel oxide concentration of 2.3 g / 100 mL by an equal-volume impregnation method. The impregnated material is dried at 120 ℃ for 6 h and calcined at 500 ℃ in a nitrogen atmosphere for 4 h to prepare the hydrogen demetallization catalyst Cat-1 of the present application. The properties of the catalyst are shown in Table 1. Example 2

[0045] The same as example 1, except that the calcination temperature of aluminum nitrate in step (1) is 600℃, and the calcination time is 6 hours. The concentration of propylene oxide in the mixed solution is 6.7wt%, and xylitol is replaced by sorbitol, the concentration of polyol is 17.5wt%, the solution dosage is 560 grams, the hydrothermal treatment temperature is 135℃, and the treatment time is 6.5 hours. The addition amount of pseudoboehmite P2 in step (2) is 186 grams, and the rolling ball time is 70 min. The rolling ball time in step (3) is 40 min, and the hydrogen demetallization catalyst Cat-2 of the application is prepared, and the catalyst properties are shown in Table 1. Example 3

[0046] The same as example 1, except that the calcination temperature of aluminum nitrate in step (1) is 650℃, and the calcination time is 4 hours. The concentration of propylene oxide in the mixed solution is 4.3wt%, and xylitol is replaced by mannitol, the concentration of polyol is 12.5wt%, the solution dosage is 750 grams, the hydrothermal treatment temperature is 155℃, and the treatment time is 4.5 hours. The addition amount of pseudoboehmite P2 in step (2) is 300 grams, and the rolling ball time is 60 min. The rolling ball time in step (3) is 50 min, and the hydrogen demetallization catalyst Cat-3 of the application is prepared, and the catalyst properties are shown in Table 1. Example 4

[0047] The same as example 1, except that the calcination temperature of aluminum nitrate in step (1) is 450℃, and the calcination time is 7 hours. The concentration of propylene oxide in the mixed solution is 7.8wt%, and xylitol is replaced by arabitol, the concentration of polyol is 19wt%, the solution dosage is 440 grams, the hydrothermal treatment temperature is 125℃, and the treatment time is 7.5 hours. The addition amount of pseudoboehmite P2 in step (2) is 168 grams, and the rolling ball time is 80 min. The rolling ball time in step (3) is 30 min, and the hydrogen demetallization catalyst Cat-4 of the application is prepared, and the catalyst properties are shown in Table 1.

[0048] Comparative example 1

[0049] The same as example 1, except that the propylene oxide in the mixed solution in step (1) is replaced by the same amount of ethylene oxide, and no sheet-shaped crystal grains are formed in the microstructure of the material P1-5 after hydrothermal treatment, and the comparative hydrogen demetallization catalyst Cat-5 is prepared, and the catalyst properties are shown in Table 1.

[0050] Comparative example 2

[0051] The same as example 1, except that aluminum nitrate in step (1) is replaced by aluminum sulfate, and the solid material particles are dissolved after hydrothermal treatment, and the product is not separated.

[0052] Comparative example 3

[0053] The same as example 1, except that aluminum nitrate is replaced by aluminum chloride in step (1), no sheet-shaped crystal grains are formed in the microstructure of the material P1-6 after hydrothermal treatment, and a comparative hydrodemetallization catalyst Cat-6 is prepared, and the catalyst properties are shown in Table 1.

[0054] Comparative example 4

[0055] The same as example 1, except that no polyol is added in the mixed solution in step (1), and the polyol is loaded on the alumina carrier by impregnation, and a comparative hydrodemetallization catalyst Cat-7 with the same carbon content is prepared, and the catalyst properties are shown in Table 1.

[0056] Table 1 Catalyst properties

[0057] Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 3 Comparative Example 4 Catalyst Cat-1 Cat-2 Cat-3 Cat-4 Cat-5 Cat-6 Cat-7 Specific surface area, m 2 / g]] 196 182 213 171 183 189 200 Pore volume, mL / g 0.91 0.89 0.92 0.88 0.79 0.81 0.91 MoO3 content, wt% 8.3 8.4 8.5 8.2 8.3 8.3 8.3 Ni content, wt% 2.3 2.4 2.5 2.4 2.2 2.3 2.4 C content, wt% 3.2 3.8 2.6 4.3 3.1 3.5 3.2 10-20 nm pore content, v% 43.6 45.7 41.5 49.3 49.9 47.7 43.9 50-100 nm pore content, v% 17.6 19.3 16.2 22.7 6.2 5.1 16.8 >100 nm pore content, v% 16.1 13.9 14.8 11.6 3.2 2.7 16.5

[0058] As shown in Table 1, the hydrodemetallization catalyst prepared by the method has higher pore content of 50-100 nm and greater than 100 nm.

[0059] The hydrodemetallization catalysts (Cat-1-Cat-7) prepared in the above examples and comparative examples are subjected to catalytic performance evaluation, and the evaluation method is as follows:

[0060] The catalytic performance of the hydrodemetallization catalysts Cat-1-Cat-7 is evaluated on a 200 mL small evaluation device with a certain residual oil as a raw material, and the metal (Ni+V) content in the raw oil is 171 μg / g, and the reaction conditions are as follows: the reaction temperature is 385 ℃, the pressure is 14.0 MPa, the liquid hourly space velocity is 0.65 h-1, the hydrogen / oil volume ratio is 850, and the content of each impurity in the generated oil is measured after 500 hours and 5000 hours of reaction, the relative removal rate of other catalyst impurities is calculated based on the metal removal rate of the comparative catalyst Cat-5 after 500 hours of reaction as 100%, and the evaluation results are shown in Table 2. -1

[0061] Table 2 Catalyst hydrogenation performance comparison

[0062] Catalyst No. Cat-1 Cat-2 Cat-3 Cat-4 Cat-5 Cat-6 Cat-7 500 hour relative demetallization (V+Ni) rate, % 137 135 140 131 100 97 129 5000 hour relative demetallization (V+Ni) rate, % 136 130 135 126 89 81 111

[0063] As shown in Table 2, when the reaction time is 500 hours, the catalyst prepared by the method has higher hydrodemetallization activity compared with the comparative catalyst. When the reaction time is 5000 hours, the catalyst prepared by the method still has higher hydrodemetallization activity compared with the comparative catalyst, which shows that the hydrodemetallization catalyst prepared by the method has higher demetallization activity and better activity stability.​

Claims

1. A method for preparing a carbon-containing hydrogenation demetallization catalyst, characterized in that... The process includes the following: (1) calcining aluminum nitrate, followed by crushing and sieving of the calcined material, mixing the sieved material with an aqueous solution containing propylene oxide and polyol, and then subjecting it to hydrothermal treatment. The treated material is then filtered, washed, and dried to obtain carbon-modified flaky boehmite P1; (2) mixing carbon-modified flaky boehmite P1 with boehmite P2 to obtain a mixture H0, which is then ball-formed to obtain an alumina carrier precursor S0; (3) the alumina carrier from step (2) is then processed into a mixture H0. The precursor S0 is mixed with carbon-modified flaky boehmite P1 and spheroidized. The shaped material is dried and calcined to obtain an alumina support; (4) the support from step (3) is impregnated with the active component impregnation solution, dried and calcined to obtain a hydrogenation demetallization catalyst; in the aqueous solution containing propylene oxide and polyols in step (1), the concentration of propylene oxide is 2.5wt%-12wt%; the mass ratio of the solution to the powder material is 3:1-10:1; in step (1) The polyols mentioned are one or more of xylitol, sorbitol, mannitol, and arabinitol. The concentration of the polyols in the aqueous solution containing propylene oxide and polyols is 10wt%-20wt%. The hydrothermal treatment in step (1) is carried out in a closed container at a temperature of 110-180℃ for 4-8 hours. The pressure inside the sealed container during hydrothermal treatment is the self-generated pressure. The mass ratio of carbon-modified flaky boehmite P1 to boehmite P2 in step (2) is 1:4-2:

3. The active component impregnation solution in step (4) is a solution containing Group VIB metals and Group VIII metals. The Group VIB metal is Mo or W, and the Group VIII metal is Ni or Co. The content of the Group VIB metal as oxides is 5.5-12.5g / 100mL, and the content of the Group VIII metal as oxides is 0.5-4.5g / 100mL. The specific surface area of ​​the catalyst is 160-280m². 2 / g, with a pore volume of 0.8-1.0mL / g, the content of pores with a diameter of 10-20nm accounts for 35%-55% of the mesopore volume, the content of pores with a diameter of 50-100nm accounts for 12.5%-25% of the total pore volume, and the content of pores with a diameter greater than 100nm accounts for 10%-20% of the total pore volume.

2. The method according to claim 1, characterized in that: The aluminum nitrate calcination temperature in step (1) is 450-650℃, the calcination time is 4-8 hours, and the particle size is greater than 100 mesh.

3. The method according to claim 1, characterized in that: In step (1), the aqueous solution containing propylene oxide and polyol has a propylene oxide concentration of 4wt%-8wt% and a solution volume to powder mass ratio of 4:1-8:

1.

4. The method according to claim 1, characterized in that: The pseudoboehmite P2 particles mentioned in step (2) are in granular form and are either commercially available products or self-made using acid precipitation, alkali precipitation, or aluminum alkoxide hydrolysis methods.

5. The method according to claim 1, characterized in that: The spherical forming in step (2) is carried out in a rotary forming machine. The rotary forming machine has the following operating conditions: the tilt angle of the rotary table is 40-70º, the rotation speed of the rotary table is 10-30 rpm, the forming time of the material in the rotary table is 10-120 min, and the radius of the alumina carrier precursor S0 is 0.4r-0.8r, where r is the radius of the alumina carrier.

6. The method according to claim 1, characterized in that: The spherical forming process described in step (3) is carried out in a rotary forming machine. The rotary forming machine operates under the following conditions: the tilt angle of the rotary table is 40-70º, the rotation speed of the rotary table is 10-30 rpm, the forming time of the material in the rotary table is 10-120 min, and an aqueous solution containing adhesive solvent is sprayed into the material during the spherical forming process. The aqueous solution containing adhesive solvent is one or a mixture of several of the aqueous solutions of nitric acid, phosphoric acid, oxalic acid, and acetic acid, and the mass percentage concentration of the solution is 1%-3%.

7. The method according to claim 1, characterized in that: The drying temperature in step (3) is 60℃-180℃ and the drying time is 1-8 hours; the calcination is carried out in an inert atmosphere at a temperature of 350-800℃ for 2-6 hours.

8. The method according to claim 1, characterized in that: The active component impregnation solution in step (4) is an ammonia solution, aqueous solution or phosphoric acid solution of Group VIB and Group VIII metals; the drying temperature is 100-160℃ and the drying time is 6-10 hours; the calcination is carried out in an inert atmosphere, the calcination temperature is 400-550℃ and the calcination time is 2-6 hours.

9. The carbon-containing hydrogenation demetallization catalyst prepared according to any one of claims 1 to 8, characterized in that: By weight, the catalyst contains 1%-5% carbon, 5%-10% molybdenum oxide, 1.3%-3% nickel oxide, and the remainder is alumina support.

10. The application of the carbon-containing hydrogenation demetallization catalyst prepared according to any one of claims 1 to 8 in the residual oil hydrogenation process.

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