Hydrodemetallization catalyst and preparation method thereof

Abstract

The present invention discloses a hydrodemetallization catalyst and its preparation method. The catalyst comprises an inner alumina layer loaded with a first active component and an outer alumina layer loaded with a second active component. The alumina pore size increases radially from the inside to the outside in a gradient pattern, with the pore size of the outer alumina layer being 5 to 15 nm larger than that of the inner alumina layer. The ratio of tetrahedral molybdenum to octahedral molybdenum in the catalyst, calculated as Mo atoms, is 0.17 to 0.30. When used in residual oil hydrodemetallization reactions, the catalyst exhibits high demetallization activity and metal-tolerance capacity, ensuring stable catalytic activity over long periods of operation.

Description

Technical Field

[0001] The present invention relates to a hydrodemetallization catalyst, in particular to a hydrodemetallization catalyst suitable for heavy oil, especially residual oil hydrotreating process, and a preparation method and application thereof. Background Art

[0002] In recent years, crude oil has become increasingly heavier and inferior in quality, while market demand for lighter oil products continues to rise. This has led to new challenges for hydrogenation technology, a key route for processing heavy oil. As the core of hydrogenation technology, catalyst preparation and performance are crucial for deep hydrogenation of heavy oil. Specifically, the hydrodemetallization reaction is a key chemical reaction occurring during residue hydroprocessing. In the presence of a catalyst, various metal compounds react with H2S to form metal sulfides, which are then deposited on the catalyst for removal. The presence of active metals on the catalyst support plays a crucial role in the catalyst's activity and stability.

[0003] CN102441399A discloses a method for preparing a hydrodemetallization catalyst, comprising preparing a Group VIB metal compound and / or a Group VIII metal compound into an ammonia solution or aqueous solution, then impregnating an alumina support, drying, and calcining the solution to produce the final catalyst. CN1289640A discloses a method for preparing a supported hydrodemetallization catalyst, which utilizes a macroporous alumina support and sprays an ammonia solution or aqueous solution of the active metal onto the support in a spray drum. This method omits the normal temperature drying process of the support after impregnation, and the sprayed support is directly placed in a calcination furnace at a temperature of 300-450°C for calcination, then gradually raised to 460-550°C and maintained at this temperature in air for 1-5 hours. CN103785400A discloses a method for preparing a highly active residue oil hydrodemetallization catalyst, comprising impregnating an alumina carrier with a polyol and / or monosaccharide aqueous solution, hydrothermally carbonizing the carrier in a sealed container, and then loading the carrier with active metal components Mo and Ni. Finally, the alumina loaded with the active components is first calcined under a nitrogen atmosphere and then calcined under an air atmosphere to produce the residue oil hydrodemetallization catalyst. CN111375419A discloses a hydrogenation catalyst and a method for preparing the same, comprising dissolving an iron-containing inorganic salt and ammonium citrate in water to produce a solution; sphericalizing the small-pore alumina and simultaneously adding the solution obtained in the first step to produce alumina; placing the alumina in a ball rolling machine, and uniformly adding the large-pore alumina and the solution obtained in the first step during rolling to produce alumina again; drying the alumina to obtain the final alumina, and then loading the active metal components to produce the catalyst.

[0004] The activity and stability of the hydrodemetallization catalyst prepared by the above method still need to be further improved. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention provides a hydrodemetallization catalyst and its preparation method. The alumina pore size in this catalyst increases radially from the inside outward in a gradient distribution. When used in residual oil hydrodemetallization reactions, it exhibits high demetallization activity and metal-tolerance capacity, ensuring stable catalyst activity over long periods of operation.

[0006] The first aspect of the present invention provides a hydrodemetallization catalyst, which includes an inner alumina layer loaded with a first active component and an outer alumina layer loaded with a second active component, wherein the pore size of the outer alumina layer is 5 to 15 nm larger than the pore size of the inner alumina layer; and the ratio of the content of tetrahedral molybdenum to octahedral molybdenum in the catalyst, calculated as Mo atoms, is 0.17 to 0.30.

[0007] In the present invention, the hydrodemetallization catalyst is in the form of spherical particles.

[0008] In the present invention, the diameter ratio of the outer aluminum oxide layer to the inner aluminum oxide layer is 2 to 10, preferably 2 to 6, and the diameter of the inner aluminum oxide layer is 0.4 to 1.8 mm, preferably 0.4 to 0.8 mm.

[0009] In the present invention, the pore size of the inner layer of aluminum oxide is 8 to 18 nm, and the pore size of the outer layer of aluminum oxide is 16 to 28 nm.

[0010] In the present invention, the first active component includes molybdenum and a Group VIII metal, and the second active component includes molybdenum and a Group VIII metal; the Group VIII metal in the first active component is preferably nickel, and the Group VIII metal in the second active component is preferably nickel.

[0011] In the present invention, based on the mass of the catalyst, the content of MoO3 is 8.0% to 18.0%, and the content of the Group VIII metal oxide is 2.0% to 8.0%.

[0012] In the present invention, based on the total mass of MoO3 in the catalyst, the content of MoO3 in the first active component is 30.0% to 60.0%, and the content of MoO3 in the second active component is 40.0% to 70.0%.

[0013] In the present invention, based on the total mass of Group VIII metal oxides in the catalyst, the content of Group VIII metal oxides in the first active component is 30.0% to 60.0%, and the content of Group VIII metal oxides in the second active component is 40.0% to 70.0%.

[0014] In the present invention, the specific surface area of ​​the catalyst is 140 to 190 m 2 / g, and a pore volume of 0.50 to 0.90 mL / g; preferably, the specific surface area of ​​the catalyst is 165 to 185 m 2 / g, and the pore volume is 0.70~0.85mL / g.

[0015] In the present invention, the catalyst further comprises an auxiliary component, which is selected from at least one of fluorine, phosphorus, silicon or boron, preferably phosphorus. The content of the auxiliary component as oxide is 1.0% to 4.0% based on the mass of the catalyst.

[0016] The second aspect of the present invention provides a method for preparing the above-mentioned hydrodemetallization catalyst, comprising the following steps:

[0017] (1) neutralizing an acidic aluminum salt solution with an alkaline aluminum salt solution and subjecting the solution to primary aging to obtain a slurry;

[0018] (2) the slurry obtained in step (1) is evenly divided into slurry I and slurry II, a water-soluble polymer J1 is added to slurry II, and slurry I and slurry II are subjected to secondary aging and drying, respectively, to obtain dried products I and dried products II;

[0019] (3) preparing the dried product II obtained in step (2) into a pseudo-boehmite mixed solution II and adjusting its pH value, sealing the solution, and obtaining a mixed solution III;

[0020] (4) adding the dried product I obtained in step (2) and the mixed solution III obtained in step (3) to a rolling ball machine at a certain rate, and simultaneously spraying the first impregnation solution containing the first active component at a uniform rate to obtain an inner layer of alumina loaded with the first active component;

[0021] (5) adjusting the relative dripping rate of the mixed solution III, and simultaneously spraying the mixed solution containing the second active component at a uniform speed, and then drying and calcining the obtained sample to obtain the hydrodemetallization catalyst.

[0022] In step (1) of the present invention, the acidic aluminum salt solution and the alkaline aluminum salt solution are added to the reactor in a parallel flow.

[0023] In step (1) of the present invention, the acidic aluminum salt solution is one or more of aluminum sulfate solution, aluminum nitrate solution, or aluminum chloride solution; the concentration of the acidic aluminum salt solution is 5 g / 100 mL to 30 g / 100 mL as calculated on the basis of Al2O3. The alkaline aluminum salt solution is one or more of sodium metaaluminate solution and potassium metaaluminate solution; the concentration of the alkaline aluminum salt solution is 8 g / 100 mL to 58 g / 100 mL as calculated on the basis of Al2O3.

[0024] In step (1) of the present invention, the neutralization reaction temperature is 80 to 130° C., the time is 30 to 150 minutes, and the pH value of the slurry is controlled to be 6.0 to 9.5 during the neutralization reaction. The pH value of the slurry is adjusted by controlling the addition rate of the acidic aluminum salt solution and the alkaline aluminum salt solution or by additionally adding an acid-base regulator during the neutralization reaction.

[0025] In step (1) of the present invention, the temperature of the primary aging is 100-230° C., the time is 60-220 minutes, and the pH value is 9.0-12.0.

[0026] In step (1) of the present invention, after the primary aging is completed, preferably, the slurry is concentrated first and then subjected to secondary aging, wherein the volume of the concentrated slurry is 40% to 70% of the original volume.

[0027] In step (2) of the present invention, the water-soluble polymer J1 is one or more of polyethylene glycol, polyvinyl alcohol, polyacrylamide and methyl cellulose, preferably polyethylene glycol; the viscosity (20°C) of the water-soluble polymer J1 is 10 to 1000 mPa·s, and the viscosity (20°C) of the slurry after adding the water-soluble polymer J1 is 150 to 650 mPa·s.

[0028] In step (2) of the present invention, the secondary aging temperature is 120-260° C., the time is 40-200 minutes, and the secondary aging temperature is 30-60° C. higher than the primary aging temperature.

[0029] In step (2) of the present invention, the drying temperature after secondary aging is 120-180°C for 2-10 hours. Filtration and washing can be performed according to conventional methods before drying. The dry matter content of the dried product I and the dried product II after drying is 40-70 wt%.

[0030] In step (3) of the present invention, the solid content of the obtained mixed solution III is 15% to 40%, the pH value ranges from 6.0 to 8.0, and the adjustment method is solvent adjustment. The solvent can be one or more of phosphoric acid, nitric acid, oxalic acid, citric acid, and tartaric acid. The sealing treatment time is 6 to 10 hours.

[0031] In step (4) of the present invention, the rotation speed of the ball rolling machine is 30-50 r / min. After the first ball forming is completed, the diameter of the obtained small balls is 0.4-1.8 mm, preferably in the range of 0.4-0.8 mm.

[0032] In step (4) of the present invention, the ratio of the addition rate of the dried product I to the mixed solution III is 0.60 to 0.95 g / ml.

[0033] In step (4) of the present invention, the amount of the first impregnation liquid used accounts for 15% to 45% of the saturated water absorption of the dried material I. The first impregnation liquid is an impregnation liquid containing Mo and a Group VIII metal (preferably Ni), wherein the active metal component molybdenum is derived from one or both of molybdenum oxide and ammonium heptamolybdate, and the nickel is derived from one or both of basic nickel carbonate and nickel nitrate. The contents of MoO3 and the Group VIII metal oxide in the first impregnation liquid are 30.0 to 60.0 g / 100 ml and 5.0 to 30.0 g / 100 ml, respectively. The amount of MoO3 introduced into the catalyst by the first impregnation liquid is 30% to 60% of the total MoO3 loading in the catalyst; and the amount of the Group VIII metal oxide introduced into the catalyst by the first impregnation liquid is 30% to 60% of the total Group VIII metal oxide loading in the catalyst.

[0034] In step (4) of the present invention, at least one auxiliary agent containing fluorine, phosphorus, silicon or boron may be introduced into the first impregnation solution, and the amount of the auxiliary agent (calculated as oxide) added is 15% to 30% of the total mass of molybdenum oxide in the first impregnation solution, preferably 18% to 26%.

[0035] In step (4) of the present invention, the first impregnation liquid preferably further contains a water-soluble polymer J2. The water-soluble polymer J2 is one or more of polyethylene glycol, polyvinyl alcohol, polyacrylamide, and methylcellulose. The viscosity of the water-soluble polymer J2 (at 20°C) is 10 to 1000 mPa·s. After the addition of the water-soluble polymer J2, the slurry viscosity (at 20°C) is 150 to 650 mPa·s.

[0036] In step (4) of the present invention, the dropping rate ratio of the first impregnation liquid to the dried material I is 0.18-0.42 ml / g, and the dropping time is based on the ball formation time.

[0037] In step (5) of the present invention, the ratio of the addition rate of the dried material I to the mixed solution III is 0.40 to 0.58 g / ml. The second impregnation solution is an impregnation solution containing Mo and a Group VIII metal (preferably Ni), wherein the active metal component molybdenum is derived from one or both of molybdenum oxide and ammonium heptamolybdate, and the nickel is derived from one or both of basic nickel carbonate and nickel nitrate. The amount of MoO3 introduced into the catalyst by the second impregnation solution is 40% to 70% of the total MoO3 loading in the catalyst; and the amount of Group VIII metal oxide introduced into the catalyst by the second impregnation solution is 40% to 70% of the total Group VIII metal oxide loading in the catalyst.

[0038] In step (5) of the present invention, the second impregnation liquid preferably further contains a water-soluble polymer J3. The water-soluble polymer J3 is one or more of polyethylene glycol, polyvinyl alcohol, polyacrylamide, and methylcellulose. The viscosity of the water-soluble polymer J3 (at 20°C) is 10 to 1000 mPa·s. After the addition of the water-soluble polymer J3, the slurry viscosity (at 20°C) is 150 to 650 mPa·s.

[0039] In step (5) of the present invention, the dripping rate ratio of the second impregnation liquid to the dried material I is 1.08-1.25 ml / g, and the dripping time is based on the final sphere size.

[0040] In step (5) of the present invention, the drying temperature is 120-200° C., and the drying time is 2-12 hours.

[0041] In step (5) of the present invention, the calcination is performed by programmed temperature increase. The heating rate is 1°C / min to 3°C / min, the calcination temperature is 450°C to 750°C, the calcination time is 3 to 8 hours, and the calcination atmosphere is one or more of nitrogen, water vapor or air, preferably air.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] For hydrodemetallization catalysts, a smooth pore structure and a reasonable distribution of active metals are crucial for overall catalyst performance. The pore distribution of the support plays a crucial role in catalytic activity and metal storage capacity. Furthermore, the reduction temperature of tetrahedral Mo species is higher than that of octahedral Mo species. The presence of tetrahedral Mo negatively impacts the interaction between the support and the metal, thereby affecting catalytic activity and stability. Through extensive research, the inventors discovered that by optimizing the support preparation, the slurry obtained after the neutralization reaction is subjected to a two-stage aging process. Before the second aging, the slurry is either not added or added with a water-soluble polymer, and the second aging is performed at a higher temperature. This yields porous materials with suitable specific surface areas and different pore size distributions, namely, dried materials I and dried materials II. Dried material II is then prepared into a pseudo-boehmite mixed solution II. After pH adjustment and sealing for a period of time, mixed solution III is obtained. Dried material I and mixed solution III are then rolled into spheres at a specific addition rate. During the sphere formation process, the first impregnation solution is sprayed into the spheres at a uniform drip rate. After the ball-shaped grains have grown to a certain size, the relative dripping rate of mixed solution III is adjusted, while the second impregnation solution is sprayed in at a constant rate. After drying and calcination, the hydrodemetallization catalyst is produced. Through the above treatment process, the pore size of the alumina increases gradually from the inside out, and the ratio of tetrahedral and octahedral molybdenum species is more optimally distributed. Furthermore, a water-soluble polymer is added to both impregnation solutions, which not only promotes the dispersion of the active metal but also appropriately adjusts the acidity of the catalyst. Through the comprehensive coordination of various steps, the method of the present invention significantly improves the activity and stability of the resulting hydrodemetallization catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a Raman spectrum of the catalyst surface obtained in Example 1;

[0045] Figure 2 This is a Raman spectrum of the catalyst surface obtained in Comparative Example 1;

[0046] Figure 3 This is a Raman spectrum of the catalyst surface obtained in Comparative Example 2;

[0047] Figure 4 This is the Raman spectrum of the catalyst surface obtained in Comparative Example 3. DETAILED DESCRIPTION

[0048] In the present invention, the Raman spectroscopic characterization of the catalyst was performed using a DXR Microscope type DXR micro Raman spectrometer from Thermo Scientific. -1 The peak near it is the peak of tetrahedral molybdenum, at 960 cm -1The nearby peak is the peak of octahedral molybdenum. The contents of tetrahedral molybdenum and octahedral molybdenum are calculated based on the area under the same baseline.

[0049] In the present invention, the ASAP-2420 physical adsorption instrument produced by Michael Company is used to characterize the pore structure (SVD) and specific surface area of ​​the catalyst.

[0050] The technical solutions and effects of the present invention are further described below with reference to the following embodiments, but are not limited to the following embodiments.

[0051] Example 1

[0052] 1.5L of aluminum sulfate aqueous solution (the concentration of Al2O3 is 10.0g / 100mL, the initial temperature is 75℃) is introduced from the top into a reactor equipped with 5L of pure water, a stirrer and a heating jacket, and 1L of sodium metaaluminate aqueous solution (the concentration of Al2O3 is 28.0g / 100mL, the initial temperature is 110℃) is introduced from the bottom of the reactor into the reactor, and the neutralization reaction temperature is controlled at 105℃; aluminum sulfate solution and sodium metaaluminate solution are added continuously, and the pH value is controlled at 8.5, and the reaction is carried out for 60 minutes; after the parallel flow is completed, an aging is carried out, and the aging temperature is 15 0°C, aging time is 120 minutes, aging pH value is 9.3; after the completion of the primary aging, the slurry volume is concentrated to 5L, and then evenly divided into two parts, namely slurry I and slurry II, 25g of polyvinyl alcohol (viscosity is 30mPa·s) is added to slurry II, and the slurry viscosity (20°C) after the addition of polyvinyl alcohol is 260mPa·s, while slurry I is not treated in any way, and then both slurry I and slurry II are heated to 180°C and subjected to secondary aging for 120 minutes, and then washed and dried to obtain dry products I and dry products II with a dry basis of 50wt% respectively;

[0053] Dried material II was mixed with deionized water at a solids content of 16.7% to obtain mixed solution II. The pH was adjusted to 6.5 and sealed for 6 hours to obtain mixed solution III. 800g of dried material I and 960ml of mixed solution III were added to the ball rolling machine at addition rates of 13.3g / min and 16.0ml / min, respectively. Simultaneously, the first impregnation solution was sprayed into the machine at a drip rate of 4.0ml / min. The content of MoO3 in the first impregnation solution is 55.6 g / 100 ml, the content of NiO is 10.3 g / 100 ml, the amount of P (calculated as oxide) in the auxiliary phosphoric acid added is 24.4% of the total mass of molybdenum oxide in the impregnation solution (the amount of the first impregnation solution used is 25% of the saturated water absorption capacity of the dry substance I), and polyacrylamide (viscosity of 950 mPa·s) is added to the first impregnation solution, and the viscosity after addition is 600 mPa·s. The amount of MoO3 introduced into the catalyst by the first impregnation solution is 40% of the total MoO3 loading in the catalyst; the amount of NiO introduced into the catalyst by the first impregnation solution is 40% of the total NiO loading in the catalyst, and the spraying time is controlled within 60 minutes.

[0054] The addition rate of the adjusted dried material I was maintained constant, and the droplet rate of the mixed solution III was adjusted to 24.0 ml / min. Simultaneously, the second impregnation solution was sprayed into the catalyst at a rate of 15.7 ml / min. Polyacrylamide (viscosity of 950 mPa·s) was added to the second impregnation solution, resulting in a viscosity of 400 mPa·s. The amount of MoO3 introduced into the catalyst by the second impregnation solution accounted for 60% of the total MoO3 loading in the catalyst, and the amount of NiO introduced into the catalyst by the second impregnation solution accounted for 60% of the total NiO loading in the catalyst. The spraying time was controlled within 60 minutes. The catalyst was then dried at 120°C for 6 hours and calcined at 750°C for 3 hours, with a heating rate of 3°C / min. Hydrodemetallation catalyst CAT-1 was obtained. The physicochemical properties of the catalyst are shown in Table 1.

[0055] Example 2

[0056] Compared with Example 1, the difference is that the initial temperature of the sodium metaaluminate aqueous solution added is 100°C, 50 g of polyvinyl alcohol (viscosity of 30 mPa·s) is added to the slurry II after the first aging, and the slurry viscosity (20°C) after the addition of polyvinyl alcohol is 280 mPa·s;

[0057] Dried material II was mixed with deionized water at a solids content of 18.2% to obtain mixed solution II. The pH was adjusted to 7.0 and sealed for 7 hours to obtain mixed solution III. 800 g of dried material I and 1040 ml of mixed solution III were added to a ball rolling machine at addition rates of 13.3 g / min and 17.3 ml / min, respectively. Simultaneously, the first impregnation solution (same as in Example 1) was sprayed into the machine at a drip rate of 4.0 ml / min.

[0058] The addition rate of the adjusted dried material I was maintained constant, resulting in a dropwise addition rate of 26.0 ml / min for the mixed solution III. Simultaneously, the second impregnation solution (same as in Example 1) was sprayed into the mixture at a rate of 15.7 ml / min. During the calcination process, the temperature was raised to 700°C at a rate of 3°C / min for 4 hours to produce the hydrodemetallization catalyst CAT-2. The physicochemical properties of the catalyst are shown in Table 1.

[0059] Example 3

[0060] Compared to Example 1, the difference is that the dried material II is mixed with deionized water at a solid content of 20.0% to obtain mixed solution II, and its pH is adjusted to 7.5. The mixture is sealed for 8 hours to obtain mixed solution III. During the ball forming process, 800g of dried material I and 1120ml of mixed solution III are added to the ball rolling machine at addition rates of 13.3g / min and 18.7ml / min, respectively. Simultaneously, the first impregnation solution (same as Example 1) is sprayed into the mixture at a drop rate of 4.0ml / min. The drop rate of mixed solution III is adjusted to 28.0ml / min, and the second impregnation solution (same as Example 1) is sprayed into the mixture at a rate of 15.7ml / min. During the calcination process, the temperature is raised to 650°C at a rate of 3°C / min for 5 hours to produce hydrodemetallization catalyst CAT-3. The physicochemical properties of the catalyst are shown in Table 1.

[0061] Example 4

[0062] Compared to Example 1, the difference is that the dried material II is mixed with deionized water at a solid content of 22.2% to obtain mixed solution II, and its pH is adjusted to 8.0. The mixture is sealed for 9 hours to obtain mixed solution III. During the ball forming process, 800g of dried material I and 1200ml of mixed solution II are added to the ball rolling machine at addition rates of 13.3g / min and 20.0ml / min, respectively. Simultaneously, the first impregnation solution (same as Example 1) is sprayed into the mixture at a drop rate of 4.0ml / min. The drop rate of mixed solution III is adjusted to 30.0ml / min, and the second impregnation solution (same as Example 1) is sprayed into the mixture at a rate of 15.7ml / min. During the calcination process, the temperature is raised to 600°C at a rate of 3°C / min and calcined for 6 hours to produce hydrodemetallization catalyst CAT-4. The physicochemical properties of the catalyst are shown in Table 1.

[0063] Comparative Example 1

[0064] The only difference compared to Example 1 is that the slurry obtained after the primary aging process is directly heated and then subjected to a secondary aging process to obtain Dried Material I. Dried Material II is then replaced with an equal amount of Dried Material I for subsequent pelletization, resulting in the hydrodemetallization catalyst dCAT-1. The physicochemical properties of this catalyst are shown in Table 1.

[0065] Comparative Example 2

[0066] The only difference from Example 1 is that during the pelletizing process, the second impregnation liquid is added first, followed by the first impregnation liquid (at the same addition rates as in Example 1). This yields a hydrodemetallization catalyst, dCAT-2. The physicochemical properties of this catalyst are shown in Table 1.

[0067] Comparative Example 3

[0068] The only difference from Example 1 is that the first and second impregnation solutions were not added during the pelletization process. Instead, the active metal was loaded via saturation impregnation after pelletization. This produced the hydrodemetallization catalyst dCAT-3. The physicochemical properties of this catalyst are shown in Table 1.

[0069] Comparative Example 4

[0070] The same procedure as in Example 1 was performed, except that the dried material I and the mixed solution III were added to the ball mill at rates of 13.3 g / min and 16.0 ml / min, respectively, throughout the ball-forming process to produce the hydrodemetallization catalyst dCAT-4. The physicochemical properties of the catalyst are shown in Table 1.

[0071] Table 1 Physicochemical properties of hydrogenation catalysts

[0072]

[0073]

[0074] Evaluation test

[0075] Activity stability tests were conducted on Examples 1 to 4 and Comparative Examples 1 to 4 in a 200 ml fixed-bed hydrogenation test apparatus. The properties of the feed oil are shown in Table 2, the test conditions are shown in Table 3, and the test results are shown in Table 4. The relative demetallization rates of the other catalysts were obtained based on the demetallization rate of catalyst dCAT-1 after 100 h of operation.

[0076] Table 2 Properties of crude oil

[0077] Raw oil properties Middle East residual oil S, wt% 2.88 Ni, μg / g 32.2 V, μg / g 58.5

[0078] Table 3 Test conditions

[0079] Reaction temperature, °C 395 Reaction pressure, MPa 15.0 <![CDATA[Liquid hourly space velocity, h -1 > 1.0 Hydrogen to oil ratio, V / V 800

[0080] Table 4 Test results of various catalysts

[0081]

[0082]

[0083] It can be seen from Tables 1-4 that the hydrodemetallization catalyst prepared according to the method of the present invention has high reaction activity and stability, and can well meet the requirements of the hydrodemetallization process of heavy oil, especially residual oil.

Claims

1. A hydrodemetallization catalyst comprising an inner alumina layer carrying a first active component and an outer alumina layer carrying a second active component, wherein: The pore size of the outer alumina layer is 5 to 15 nm larger than the pore size of the inner alumina layer; the ratio of tetrahedral molybdenum to octahedral molybdenum in the catalyst, calculated as Mo atoms, is 0.17 to 0.30; the pore size of the inner alumina layer is 8 to 18 nm, and the pore size of the outer alumina layer is 16 to 28 nm; the diameter ratio of the outer alumina layer to the inner alumina layer is 2 to 10, and the diameter of the inner alumina layer is 0.4 to 1.8 mm; The preparation method of the catalyst comprises the following steps: (1) Acidic aluminum salt solution and alkaline aluminum salt solution are subjected to neutralization reaction and primary aging to obtain a slurry; (2) The slurry obtained in step (1) is evenly divided into slurry I and slurry II, a water-soluble polymer J1 is added to slurry II, and slurry I and slurry II are subjected to secondary aging and drying, respectively, to obtain dried products I and dried products II; (3) preparing the dried product II obtained in step (2) into a pseudo-boehmite mixed solution II and adjusting its pH value, sealing the solution, and obtaining a mixed solution III; (4) adding the dried product I obtained in step (2) and the mixed solution III obtained in step (3) to a rolling ball machine at a certain rate, and simultaneously spraying the first impregnation solution containing the first active component at a uniform rate to obtain an inner layer of alumina loaded with the first active component; (5) adjusting the relative dripping rate of the mixed solution III, and simultaneously spraying the mixed solution containing the second active component at a uniform speed, and then drying and calcining the obtained sample to obtain the hydrodemetallization catalyst; In step (1), the temperature of the primary aging is 100-230°C, and in step (2), the temperature of the secondary aging is 120-260°C, and the temperature of the secondary aging is 30-60°C higher than the temperature of the primary aging; In step (4), the ratio of the addition rate of the dried product I to the mixed solution III is 0.60-0.95 g / mL, and the ratio of the dropwise addition rate of the first impregnation solution to the dried product I is 0.18-0.42 mL / g; In step (5), the ratio of the addition rate of the dried product I to the mixed solution III is 0.40-0.58 g / mL, and the ratio of the dropwise addition rate of the second impregnation solution to the dried product I is 1.08-1.25 mL / g.

2. The catalyst according to claim 1, characterized in that The diameter ratio of the aluminum oxide outer layer to the aluminum oxide inner layer is 2-6, and the diameter of the aluminum oxide inner layer is 0.4-0.8 mm.

3. The catalyst according to claim 1, characterized in that The first active component includes molybdenum and a Group VIII metal, and the second active component includes molybdenum and a Group VIII metal.

4. The catalyst according to claim 3, characterized in that The Group VIII metal in the first and second active components is nickel.

5. The catalyst according to claim 1, characterized in that Based on the mass of the catalyst, the content of MoO3 is 8.0% to 18.0%, and the content of the Group VIII metal oxide is 2.0% to 8.0%.

6. The catalyst according to claim 1, characterized in that The specific surface area of ​​the catalyst is 140~190m 2 / g, and the pore volume is 0.50~0.90mL / g.

7. The catalyst according to claim 1, characterized in that The specific surface area of ​​the catalyst is 165~185m 2 / g, and the pore volume is 0.70~0.85mL / g.

8. The catalyst according to claim 1, characterized in that The catalyst includes an auxiliary component, and the auxiliary component is selected from at least one of fluorine, phosphorus, silicon or boron.

9. The catalyst according to claim 8, characterized in that The auxiliary component is phosphorus.

10. The catalyst according to claim 8 or 9, characterized in that Based on the mass of the catalyst, the content of the auxiliary component in terms of oxide is 1.0% to 4.0%.

11. A method for preparing the catalyst according to any one of claims 1 to 7, comprising the steps of: (1) Acidic aluminum salt solution and alkaline aluminum salt solution are subjected to neutralization reaction and primary aging to obtain a slurry; (2) The slurry obtained in step (1) is evenly divided into slurry I and slurry II, a water-soluble polymer J1 is added to slurry II, and slurry I and slurry II are subjected to secondary aging and drying, respectively, to obtain dried products I and dried products II; (3) preparing the dried product II obtained in step (2) into a pseudo-boehmite mixed solution II and adjusting its pH value, sealing the solution, and obtaining a mixed solution III; (4) adding the dried product I obtained in step (2) and the mixed solution III obtained in step (3) to a rolling ball machine at a certain rate, and simultaneously spraying the first impregnation solution containing the first active component at a uniform rate to obtain an inner layer of alumina loaded with the first active component; (5) adjusting the relative dripping rate of the mixed solution III, and simultaneously spraying the mixed solution containing the second active component at a uniform speed, and then drying and calcining the obtained sample to obtain the hydrodemetallization catalyst; In step (1), the temperature of the primary aging is 100-230°C, and in step (2), the temperature of the secondary aging is 120-260°C, and the temperature of the secondary aging is 30-60°C higher than the temperature of the primary aging; In step (4), the ratio of the addition rate of the dried product I to the mixed solution III is 0.60-0.95 g / mL, and the ratio of the dropwise addition rate of the first impregnation solution to the dried product I is 0.18-0.42 mL / g; In step (5), the ratio of the addition rate of the dried product I to the mixed solution III is 0.40-0.58 g / mL, and the ratio of the dropwise addition rate of the second impregnation solution to the dried product I is 1.08-1.25 mL / g.

12. The preparation method according to claim 11, characterized in that In step (1), the acidic aluminum salt solution and the alkaline aluminum salt solution are subjected to a parallel neutralization reaction; the acidic aluminum salt solution is one or more of aluminum sulfate solution, aluminum nitrate solution or aluminum chloride solution; the concentration of the acidic aluminum salt solution in terms of Al2O3 is 5g / 100mL~30g / 100mL; the alkaline aluminum salt solution is one or both of sodium metaaluminate solution and potassium metaaluminate solution; the concentration of the alkaline aluminum salt solution in terms of Al2O3 is 8g / 100mL~58g / 100mL.

13. The preparation method according to claim 11, characterized in that In step (1), the neutralization reaction temperature is 80-130° C., the time is 30-150 minutes, and the pH value of the slurry is controlled to be 6.0-9.5 during the neutralization reaction.

14. The preparation method according to claim 11, characterized in that In step (1), the primary aging time is 60 to 220 minutes, and the pH value is 9.0 to 12.

0.

15. The preparation method according to claim 11, characterized in that In step (2), the water-soluble polymer J1 is one or more of polyethylene glycol, polyvinyl alcohol, polyacrylamide and methyl cellulose; the viscosity of the water-soluble polymer J1 at 20°C is 10~1000 mPa·s, and the viscosity of the slurry at 20°C after adding the water-soluble polymer J1 is 150~650 mPa·s.

16. The preparation method according to claim 11, characterized in that In step (2), the water-soluble polymer J1 is polyethylene glycol.

17. The preparation method according to claim 11, characterized in that In step (2), the secondary aging time is 40 to 200 minutes.

18. The preparation method according to claim 11, characterized in that In step (2), the drying temperature after secondary aging is 120-180° C., the drying time is 2-10 h, and the dry basis contents of the dried products I and II obtained after drying are both 40 wt %-70 wt %.

19. The preparation method according to claim 11, characterized in that In step (3), the solid content of the obtained mixed solution III is 15% to 40%, the pH value ranges from 6.0 to 8.0, and the sealing treatment time is 6 to 10 hours.

20. The preparation method according to claim 11, characterized in that In step (4), at least one auxiliary agent containing fluorine, phosphorus, silicon or boron is introduced into the first impregnation solution, and the amount of the auxiliary agent added is 15% to 30% of the total mass of the molybdenum oxide in the first impregnation solution.

21. The preparation method according to claim 11, characterized in that The amount of the additive added is 18% to 26% of the total mass of the molybdenum oxide in the first impregnation solution.

22. The preparation method according to claim 11, characterized in that In step (4), the amount of the first impregnation liquid used is 15% to 45% of the saturated water absorption of the dried material I.

23. The preparation method according to claim 11, characterized in that In step (5), the calcination is carried out by programmed temperature increase; the heating rate is 1°C / min~3°C / min, the calcination temperature is 450~750°C, the calcination time is 3~8 hours, and the calcination atmosphere is one or more of nitrogen, water vapor or air.

24. The preparation method according to claim 11, characterized in that In step (5), the calcination atmosphere is air.

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