A hydroprocessing catalyst, its preparation method and use

Abstract

The application discloses a kind of hydroprocessing catalyst and its preparation method and application.The catalyst includes carrier and hydrogenation active metal component and phosphorus, wherein, from the center of the cross section of catalyst particle to outer surface, the concentration of hydrogenation active metal component presents first constant-then reduces distribution trend, and the concentration of phosphorus presents gradually reduces distribution trend.The hydroprocessing catalyst can be used as main hydrogenation catalyst, which has certain capacity and higher diffusion mass transfer efficiency, and also has higher hydrogenation activity and stability.

Description

Technical Field

[0001] This invention belongs to the field of catalysis technology, specifically, it relates to a hydrogenation catalyst, its preparation method, and its application. Background Technology

[0002] Currently, with the increase in refining capacity and depth, the quality of feedstock oils is deteriorating, leading to increased processing difficulties. This is particularly true in the processing of heavy feedstock oils, where the content of impurities such as metals, sulfur, nitrogen, and gums is increasing, significantly raising the processing requirements of the hydrogenation process. Furthermore, the processing of feedstock oils containing special additives also faces significant challenges. The impact of inferior feedstocks on hydrogenation units manifests as increased catalyst bed pressure drop and rapid catalyst deactivation, severely hindering the long-term stable operation of hydrogenation units. To better utilize these inferior feedstock oils, engineers are employing various methods to improve the overall performance of catalysts. For example, researchers are developing various catalysts with different functions and grading them according to specific rules to optimize catalyst operating cycles. Most development of protective agents or main catalysts focuses on optimizing the pore structure of the support and enhancing the intrinsic activity of active metals. However, analysis of spent catalysts from industrial plants shows that most impurities are deposited on the surface of the catalyst particles, while the interior of the catalyst still retains high activity. Therefore, reducing the deposition rate and amount of impurities on the surface of catalyst particles, thereby improving the mass transfer efficiency of catalyst particles, is the main direction to be considered in catalyst research and development.

[0003] CN1102448C discloses a method for preparing a hydrogenation demetallization catalyst with a non-uniform distribution of active metals. The method uses θ- or δ-type alumina as a support, and through unsaturated impregnation, supports metal components such as Mo, W, Co, and Ni. The catalyst is then dried at low temperature or air-dried, and subsequently calcined to obtain the hydrogenation catalyst. The concentration of metal components in the resulting hydrogenation catalyst particles gradually increases from the outer surface to the center of the particle.

[0004] CN101462080A discloses a method for preparing a catalyst with non-uniformly distributed active metal components. The method involves mixing an acid solution such as nitric acid or phosphoric acid with at least one compound containing a Group VIB metal component, at least one compound containing a Group VIII metal component, and water to form a solution. A surfactant is then introduced, and the solution is impregnated with a catalyst support at room temperature. After drying at 60-160°C for a period of time and calcining, the resulting catalyst exhibits a non-uniform distribution of metal components, gradually increasing in quantity from the outer surface to the center.

[0005] CN102861598A discloses a fluorinated hydrogenation catalyst with non-uniformly distributed active metal components and its preparation. The catalyst comprises a shaped fluorinated hydrated alumina support, at least one metal salt selected from Group VIII non-noble metals and at least one metal salt selected from Group VIB metals supported on the support, wherein, along the radial cross-section of the catalyst, the ratio of the outer surface concentration to the central concentration of the Group VIII metal component is 0.1-0.9; and the ratio of the outer surface concentration to the central concentration of the Group VIB metal component is 0.1-0.8.

[0006] The active metals in the aforementioned hydrogenation catalysts exhibit a significant radial gradient, making them primarily suitable for use as hydrogenation protectants or demetallization catalysts for removing heavy impurities. However, their metal content is limited, making them unsuitable for preparing high-metal-content hydrogenation catalysts. As the main catalyst for hydrogenation, a catalyst needs both sufficient impurity tolerance and diffusion mass transfer efficiency, as well as a certain proportion of stable active centers. Therefore, catalysts with the aforementioned non-uniform distribution of active metals no longer meet the requirements for main catalysts. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a hydrotreating catalyst and its preparation method. This hydrotreating catalyst can serve as a primary hydrotreating catalyst, possessing both a certain degree of impurity tolerance and high diffusion mass transfer efficiency, as well as high hydrogenation activity and stability.

[0008] The first aspect of the present invention provides a hydrogenation treatment catalyst, comprising a support, a hydrogenation active metal component, and phosphorus, wherein, from the center of the cross-section of the catalyst particle to the outer surface, the concentration of the hydrogenation active metal component exhibits a distribution trend of first being constant and then decreasing, and the phosphorus concentration exhibits a distribution trend of gradually decreasing.

[0009] In the catalyst of the present invention, the thickness of the portion of the hydrogenation active metal component with decreasing concentration is H, the cross-sectional radius of the catalyst is R, and the ratio of H / R is 0.20 to 0.80, preferably 0.24 to 0.76.

[0010] In the catalyst of the present invention, the ratio of the concentration of the group VIII metal component (denoted as A1) of the outer surface of the catalyst particle cross-section to the concentration of the group VIII metal component in the region of constant concentration of hydrogenation active metal component is 0.25 to 0.80, preferably 0.30 to 0.75, and the ratio of the concentration of the group VIB metal component (denoted as A2) is 0.32 to 0.80, preferably 0.32 to 0.75.

[0011] In the catalyst of the present invention, the ratio of the concentration of Group VIII metal component at half the thickness (H / 2) of the region where the concentration of hydrogenation active metal component decreases to that in the region where the concentration of hydrogenation active metal component is constant (denoted as B1) is 0.64 to 0.88, preferably 0.65 to 0.85, and the ratio of the concentration of Group VIB metal component (denoted as B2) is 0.68 to 0.88, preferably 0.70 to 0.86.

[0012] In the catalyst of the present invention, preferably, B1 is at least 0.08 higher than A1, more preferably 0.10 to 0.40.

[0013] In the catalyst of the present invention, preferably, B2 is at least 0.10 higher than A2, more preferably 0.10 to 0.40.

[0014] In the catalyst of the present invention, in the region of constant concentration of hydrogenation active metal component, the concentration difference of hydrogenation active metal component at different locations is less than 0.05, preferably less than 0.03. Further, the concentration difference of Group VIII metal component at different locations is less than 0.05, preferably less than 0.03, and the concentration difference of Group VIB metal component at different locations is less than 0.05, preferably less than 0.03.

[0015] In the catalyst of this invention, the hydrogenation active metal is a Group VIB metal and a Group VIII metal, wherein the Group VIB metal is Mo and / or W, and the Group VIII metal is Ni and / or Co.

[0016] In the catalyst of the present invention, based on the mass of the final hydrogenation catalyst, the mass content of Group VIB metal oxide is 8% to 38%, preferably 14% to 30%, and the mass content of Group VIII metal oxide is 2% to 10%, preferably 3% to 7%.

[0017] In the catalyst of the present invention, the ratio of phosphorus concentration on the outer surface of the catalyst particle cross-section to that at the center is 0.75 to 0.95, preferably 0.78 to 0.92.

[0018] In the catalyst of this invention, based on the mass of the catalyst, the mass content of phosphorus, calculated as an element, is 1.0% to 4.0%, preferably 1.2% to 3.8%.

[0019] In the catalyst of this invention, the support is preferably an alumina-based support. In addition to alumina, the support may also contain a modifying agent, which may be one or more of fluorine, zirconium, silicon, etc. The support is a molded support, and may be spherical, columnar, etc.

[0020] In the catalyst of this invention, the support has a pore volume of 0.55–1.05 mL / g and a specific surface area of ​​170–380 m². 2 / g.

[0021] In the catalyst of this invention, the catalyst is in particulate form, which may be spherical, columnar, etc.

[0022] A second aspect of the present invention provides a method for preparing a hydrogenation catalyst, comprising the following steps:

[0023] (1) The carrier is impregnated with an alcohol solution of fatty acid esters and then dried;

[0024] (2) The dried material obtained in step (1) is soaked in a phosphorus-containing solution and then directly cured.

[0025] (3) The cured material obtained in step (2) is immersed in a solution containing hydrogenated active metal components, and then cured, dried and calcined to obtain the hydrogenated catalyst.

[0026] In step (1), the fatty acid ester can be one or more fatty acid methyl esters having 4 to 18 carbon atoms, such as at least one of methyl butyrate, methyl valerate, and methyl oleate. The amount of the fatty acid ester used is 2.0% to 6.5% of the carrier mass, preferably 2.5% to 6.0%.

[0027] In step (1), the alcohol in the alcohol solution can be one or more of methanol, ethanol, and propanol, and the amount of the alcohol solution is 35% to 80% of the volume of water saturated on the carrier, preferably 40% to 80%.

[0028] In step (1), the immersion method of the fatty acid ester alcohol solution is preferably spray immersion, the spraying time is 0.5h to 5.0h, preferably 0.5h to 4.0h, and the immersion temperature is 15℃ to 45℃, preferably 15℃ to 40℃. The drying temperature in step (1) is 50℃ to 90℃, preferably 55℃ to 85℃, and the drying time is 0.5h to 4.0h, preferably 0.5h to 3.0h.

[0029] In step (1), the carrier is preferably an alumina-based carrier, which can be commercially available alumina or alumina prepared by conventional methods, or alumina containing conventional additives. The conventional additives can be one or more of fluorine, zirconium, silicon, etc. The shaped carrier can be spherical, columnar, etc. Further, the pore volume of the shaped carrier is 0.55–1.05 mL / g, and the specific surface area is 170–380 m². 2 / g.

[0030] In step (2), the phosphorus source of the phosphorus-containing solution is a compound containing pyrophosphate, preferably one or more of pyrophosphate, sodium pyrophosphate, and potassium pyrophosphate. The mass concentration of phosphorus in the phosphorus-containing solution is 3.0% to 9.0%, preferably 3.2% to 8.5%. The amount of the phosphorus-containing solution used is 15% to 40% of the saturated adsorption water volume of the carrier, preferably 20% to 40%. Based on the final catalyst mass, the amount of phosphorus used, calculated as elemental, is 0.3% to 2.2%, preferably 0.5% to 2.0%.

[0031] In step (2), the soaking time is 0.5h to 3h, preferably 1h to 3h, the soaking temperature is 25℃ to 50℃, preferably 25℃ to 45℃, the static curing time is 1.0h to 6.0h, preferably 1.5h to 4.0h, and the static curing temperature is 15℃ to 40℃, preferably 25℃ to 40℃.

[0032] In step (3), the hydrogenated active metal is a Group VIII metal or a Group VIB metal, wherein the Group VIB metal is Mo and / or W, and the Group VIII metal is Ni and / or Co. In the solution containing the hydrogenated active metal component, there are no special requirements for the Group VIII metal source or the Group VIB metal source in this invention; they can be selected with reference to existing technologies. Preferably, the solution containing the hydrogenated active metal component is an aqueous solution containing a Group VIII metal compound, a Group VIB metal compound, and a phosphorus-containing compound.

[0033] In step (3), preferably, the method for preparing the aqueous solution containing the Group VIII metal compound, the Group VIB metal compound and the phosphorus-containing compound can be carried out according to the following steps: adding the Group VIII metal compound and the Group VIB metal compound to the aqueous solution containing the phosphorus-containing compound, and heating to boiling until completely dissolved to form a homogeneous solution.

[0034] In step (3), the group VIB metal compound can be one or more of their corresponding compounds, such as molybdenum source can be one or more of molybdenum oxide and molybdate; tungsten source can be one or more of sodium tungstate, ammonium metatungstate, tungstic acid, etc.

[0035] In step (3), the group VIII metal compound can be one or more of their corresponding compounds, the nickel source can be one or more of nickel nitrate, nickel chloride, and basic nickel carbonate, and the cobalt source can be one or more of cobalt nitrate, cobalt chloride, and basic cobalt carbonate.

[0036] In step (3), the phosphorus-containing compound may be one or more of phosphoric acid, phosphorous acid, pyrophosphoric acid, metaphosphoric acid, etc., or one or more of sodium phosphate, ammonium dihydrogen phosphate, sodium phosphite, etc.

[0037] In step (3), the impregnation is a saturated impregnation. The amount of the solution containing the hydrogenated active metal component is the volume of the saturated adsorbed water on the carrier minus the volume of the phosphorus-containing solution used in step (2).

[0038] In step (3), the soaking time is 0.5h to 3h, preferably 0.5h to 2.5h, and the soaking temperature is 20℃ to 50℃, preferably 25℃ to 50℃. The conditioning conditions are as follows: conditioning time is 3h to 24h, preferably 5h to 18h; conditioning temperature is 15℃ to 40℃, preferably 15℃ to 30℃.

[0039] In step (3), the drying conditions are as follows: drying time is 2-10 hours, preferably 3-6 hours, and drying temperature is 100-160°C. The calcination conditions are as follows: calcination temperature is 380-600°C, and calcination time is 2-6 hours.

[0040] In the catalyst prepared by the method of the present invention, the concentration of the hydrogenation active metal component in the cross-section of the catalyst particle shows a trend of first being constant and then decreasing from the center of the catalyst particle to the outer surface, so that the region with constant concentration of hydrogenation active metal component in the catalyst particle forms a highly active hydrogenation reaction zone.

[0041] The third aspect of this invention provides the application of the above-mentioned catalyst in the hydrotreating of heavy oil feedstock.

[0042] In the application of this invention, the above-mentioned catalyst is particularly suitable as a main hydrogenation catalyst, such as a hydrocracking pretreatment catalyst or a diesel hydrotreating pretreatment catalyst.

[0043] In the application of this invention, the heavy oil feedstock can be at least one of vacuum gas oil, coal tar, coal liquefaction oil, catalytic cracking diesel, catalytic cracking cycle oil, etc.

[0044] In this invention, the operating conditions for the hydrogenation treatment are as follows: total reaction pressure 6.0–20.0 MPa, liquid hourly space velocity 0.3–3.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 400:1 to 1800:1, and the reaction temperature is 330℃ to 440℃.

[0045] Compared with the prior art, the hydrogenation catalyst and its preparation method of the present invention have the following beneficial effects:

[0046] 1. The inventors of this invention discovered that in existing hydrotreating catalysts, the concentration of the active hydrogenating metal gradually increases from the outer surface to the center. While this improves the catalyst's tolerance, it also affects its activity. Further research revealed that when the concentration of the active hydrogenating metal in the hydrotreating catalyst exhibits a distribution trend of first being constant and then decreasing from the center to the outer surface, it possesses both a certain tolerance and high diffusion mass transfer efficiency, as well as high hydrogenation activity and stability, making it particularly suitable for use as a primary hydrotreating catalyst.

[0047] 2. In the preparation method of the catalyst of this invention, fatty acid esters are introduced to perform shallow modification on the molded support particles. Because these esters are insoluble in water, pyrophosphate ions in the subsequent phosphorus-containing solution can enter the particle interior along with the aqueous solution. When impregnating the loaded hydrogenation active metal, the pyrophosphate ions interact with the hydrogenation active metal, increasing the solubility of the hydrogenation active metal in the solution and reducing the migration of hydrogenation active metal ions during the drying process, forming a region with a constant concentration of hydrogenation active metal inside the particle. Furthermore, the shallow modification of the molded support with fatty acid esters can occupy sites on the surface, reducing the adsorption amount of the hydrogenation active metal solution, resulting in a gradual decrease in concentration from the inside to the outside of the catalyst particle. The hydrogenation treatment catalyst prepared by the method of this invention provides both a spatial channel for impurities to penetrate deep into the particle interior and a stable reaction site for deep hydrogenation and impurity removal. This catalyst is beneficial for the long-term stable operation of the hydrogenation treatment device and also possesses high hydrogenation activity. Detailed Implementation

[0048] The technical solution of the present invention is further described below through embodiments, but it should not be considered that the present invention is limited to these embodiments. The percentages mentioned in the present invention are weight percentages unless otherwise specified.

[0049] In this invention, the outermost point of the catalyst particle's cross-section, i.e., the outer surface, is taken as the starting point, and the center point of the catalyst particle's cross-section is taken as the ending point. Connecting the starting point and the ending point yields a straight line segment, i.e., the cross-sectional radius of the cross-section, with a length of R. The thickness of the portion where the concentration of the hydrogenated active metal component decreases is H, which is the length along the cross-sectional radius from the outer surface to the starting point of the region where the concentration of the hydrogenated active metal component is constant.

[0050] In the hydrogenation catalyst of this invention, the concentration distribution of the hydrogenation active metal component on the cross-section of the catalyst particle, from the center to the outer surface, shows a trend of first being constant and then decreasing. Here, "constant" means that the concentration of the hydrogenation active metal component is basically the same, and "decreasing" means that the concentration of the hydrogenation active metal component gradually decreases.

[0051] In this invention, "substantially the same" and "substantially gradually decreasing" refer to the distribution trend of the concentration of the active metal element along the cross-sectional radius, but one or more local intervals are allowed; within these local intervals, the concentration distribution of the hydrogenation active metal component along the cross-sectional radius exhibits different trends and / or a disordered state. The premise is that the existence of such local intervals is tolerable or negligible to those skilled in the art, or unavoidable given the current level of technological development in the field, and that the existence of these local intervals does not affect those skilled in the art from still determining the concentration distribution of the hydrogenation active metal component in the entire catalyst particle as "substantially the same" or "substantially gradually decreasing." Furthermore, the existence of these local intervals does not affect the achievement of the intended purpose of this invention, is acceptable, and is also included within the scope of protection of this invention.

[0052] In this invention, the hydrotreating catalyst is in the form of (solid) granules. Various shapes conventionally used in the art for hydrotreating catalysts can be cited as examples of the shape of the particles, such as spherical and columnar shapes. Examples of spherical shapes include round spheres, ellipsoids, and toothed spheres; examples of columnar shapes include cylindrical, square columnar, and irregularly shaped cross-section (e.g., cloverleaf, four-leaf clover) columnar shapes. The particle length of the hydrotreating catalyst is generally 3–8 mm, preferably 3–5 mm, and the particle diameter is 1–5 mm.

[0053] In this invention, the "cross-section of a catalyst particle" refers to the entire surface exposed after cutting along the direction of the smallest dimension of a catalyst particle through its geometric center. For example, when the catalyst particle is spherical, the cross-section refers to the entire surface exposed after cutting along the radius or minor axis of the sphere through its center. Alternatively, when the catalyst particle is columnar, the cross-section refers to the entire surface exposed after cutting perpendicular to the length dimension of the column through its center point. In this invention, the outer periphery of the exposed surface is referred to as the outermost edge of the cross-section, i.e., the outer surface, and the geometric center (such as the aforementioned center of the sphere or the center point of the length dimension) is referred to as the center point on the cross-section.

[0054] In this invention, the concentration of hydrogenated active metals was measured using the EPMA method, in accordance with GB / T15074-2008 (General Rules for Electron Probe Quantitative Analysis), on an electron probe microanalyzer (JXA-8230, manufactured by Nippon Electron Ltd.). The measurement conditions were: accelerating voltage 15 kV, beam current 5 × 10⁻⁸ A, beam spot diameter 1 μm, X-ray detection angles: W 53°, Mo 38°, Ni 24°, Co 26°, correction method: ZAF correction method, standards used: pure metal oxide standards (NiO, CoO, MoO₃, and WO₃, respectively), accuracy: less than 1%, secondary electron image resolution: 3 nm (LaB₆), line series: Kα for Ni and Co, Lα for Mo, and Mα for W.

[0055] In this invention, the specific surface area and pore volume of the alumina support were determined using a Micromeritics TriStar II 3020 adsorption instrument via low-temperature nitrogen physical adsorption. The sample was activated at 350℃ under vacuum for 3 hours, and the adsorption-desorption isotherm of the calcined alumina support was measured at liquid nitrogen temperature.

[0056] Both the examples and comparative examples used commercially available cylindrical alumina supports for catalyst preparation. The alumina supports had a diameter of approximately 1.7 mm, a particle length of 3-4 mm, a pore volume of 0.74 mL / g, and a specific surface area of ​​323 m². 2 / g, the water absorption capacity of an equal volume is 103mL / g.

[0057] Example 1

[0058] 100g of commercially available alumina support was sprayed and impregnated with 45mL of an ethanol solution containing 3.2g of methyl butyrate at 20°C for 4 hours, followed by drying at 58°C for 2.5 hours to obtain a dried product. Then, the dried product was impregnated with 28mL of an aqueous solution containing 4.9g of pyrophosphate at 32°C and cured for 2 hours to obtain a cured material. Molybdenum trioxide and nickel nitrate were dissolved in an aqueous solution of phosphoric acid and heated until a homogeneous solution (Mo-Ni-P solution) was formed. 75mL of the Mo-Ni-P solution was used to impregnate the cured material at 35°C for 5 hours at 20°C. Then, the material was dried at 120°C for 5 hours and calcined at 420°C for 3 hours to obtain the hydrotreating catalyst C1.

[0059] Example 2

[0060] 100g of commercially available alumina support was sprayed and impregnated with 76mL of an ethanol solution containing 6.0g of methyl butyrate at 33°C for 2 hours, followed by drying at 72°C for 1.5 hours to obtain a dried product. Then, the dried product was impregnated with 17mL of an aqueous solution containing 3.6g of pyrophosphate at 43°C and cured for 1.5 hours to obtain a cured material. Next, molybdenum trioxide and nickel nitrate were dissolved in an aqueous solution of phosphoric acid and heated until a homogeneous Mo-Ni-P solution was formed. 86mL of the Mo-Ni-P solution was used to impregnate the cured material at 45°C; the curing time was 8 hours at 25°C. Finally, the material was dried at 120°C for 5 hours and then calcined at 420°C for 3 hours to obtain the hydrotreating catalyst C2.

[0061] Example 3

[0062] 100g of commercially available alumina support was sprayed and impregnated with 58mL of an ethanol solution containing 2.6g of methyl butyrate at 35°C for 2 hours, followed by drying at 85°C for 2 hours to obtain a dried product. Then, the dried product was impregnated with 34mL of an aqueous solution containing 7.4g of pyrophosphate at 40°C and cured for 2 hours to obtain a cured material. Next, molybdenum trioxide and nickel nitrate were dissolved in an aqueous solution of phosphoric acid and heated until a homogeneous Mo-Ni-P solution was formed. 80mL of the Mo-Ni-P solution was used to impregnate the cured material at 25°C; the curing time was 12 hours at 15°C. Finally, the material was dried at 120°C for 5 hours and calcined at 420°C for 3 hours to obtain the hydrotreating catalyst C3.

[0063] Example 4

[0064] 100g of commercially available alumina support was sprayed and impregnated with 38mL of an ethanol solution containing 4.6g of methyl valerate at 42℃ for 1.5h, followed by drying at 65℃ for 3h to obtain a dried product. Then, the dried product was impregnated with 23mL of an aqueous solution containing 3.3g of pyrophosphate at 35℃ for 1.5h to obtain a cured material. Next, molybdenum trioxide and nickel nitrate were dissolved in an aqueous solution of phosphoric acid and heated until a homogeneous solution, i.e., a Mo-Ni-P solution, was formed. 83mL of the Mo-Ni-P solution was used to impregnate the cured material at 35℃; the curing time was 8h at 20℃. Finally, the material was dried at 120℃ for 5h and calcined at 420℃ for 3h to obtain the hydrotreating catalyst C4.

[0065] Example 5

[0066] 100g of commercially available alumina support was impregnated with 43mL of methanol solution containing 5.2g of methyl valerate at 25°C for 3 hours, followed by drying at 55°C for 3 hours to obtain a dried product. Then, the dried product was impregnated with 40mL of aqueous solution containing 5.9g of pyrophosphate at 25°C for 3.5 hours to obtain a cured material. Next, molybdenum trioxide and nickel nitrate were dissolved in an aqueous solution of phosphoric acid and heated until a homogeneous Mo-Ni-P solution was formed. 63mL of the Mo-Ni-P solution was sprayed onto the cured material at 35°C for 12 hours. After impregnation, the support was dried at 160°C for 3 hours and then calcined at 420°C for 3 hours to obtain the hydrotreating catalyst C5.

[0067] Example 6

[0068] 100g of commercially available alumina support was sprayed and impregnated with a methanol solution containing 3.7g of methyl oleate at 30°C for 2.5h, followed by drying at 60°C for 3.5h to obtain a dried product. Then, the dried product was impregnated with an aqueous solution containing 5.5g of sodium pyrophosphate at 33°C for 3h to obtain a cured material. Next, molybdenum trioxide and nickel nitrate were dissolved in an aqueous phosphoric acid solution and heated until a homogeneous Mo-Ni-P solution was formed. 62mL of the Mo-Ni-P solution was used to impregnate the cured material at 40°C for 6h at 30°C. Finally, the material was dried at 120°C for 5h and calcined at 420°C for 3h to obtain the hydrotreating catalyst C6.

[0069] Example 7

[0070] 100g of commercially available alumina support was sprayed and impregnated with 55mL of an ethanol solution containing 5.6g of methyl oleate at 36°C for 1.0h, followed by drying at 80°C for 2.5h to obtain a dried product. Then, the dried product was impregnated with 25mL of an aqueous solution containing 3.8g of sodium pyrophosphate at 28°C for 3.5h to obtain a cured material. Next, molybdenum trioxide and nickel nitrate were dissolved in an aqueous phosphoric acid solution and heated until a homogeneous Mo-Ni-P solution was formed. 78mL of the Mo-Ni-P solution was used to impregnate the cured material at 30°C for 7h at 25°C. After drying at 120°C for 5h, the material was calcined at 420°C for 3h to obtain the hydrotreating catalyst C7.

[0071] Comparative Example 1

[0072] Molybdenum trioxide and nickel nitrate were dissolved in an aqueous solution of phosphoric acid and heated until a homogeneous Mo-Ni-P solution was formed. 103 mL of the Mo-Ni-P solution was used to impregnate 100 g of commercially available alumina support at 40 °C for 6 h; the solution was then cured at 25 °C for 5 h; finally, it was dried at 120 °C for 5 h and calcined at 420 °C for 3 h to obtain the hydrotreating catalyst DC1. The concentrations of Mo, Ni, and P in the hydrotreating catalyst DC1 were uniformly distributed.

[0073] Comparative Example 2

[0074] 100g of commercially available alumina support was sprayed and impregnated with a methanol solution containing 3.7g of methyl oleate at 30°C for 2.5h, followed by drying at 60°C for 3.5h to obtain a dried product. Then, molybdenum trioxide and nickel nitrate were dissolved in an aqueous phosphoric acid solution and heated until a homogeneous Mo-Ni-P solution was formed. 103mL of the Mo-Ni-P solution was measured and impregnated onto the dried product at 40°C for 6h; a curing time of 5h was then performed at 25°C; followed by drying at 120°C for 5h and calcination at 420°C for 3h to obtain the hydrotreating catalyst DC2. The concentrations of Mo, Ni, and P in the hydrotreating catalyst DC2 showed a gradually decreasing trend from the center to the outer surface.

[0075] Comparative Example 3

[0076] 100g of commercially available alumina support was impregnated with 41mL of an aqueous solution containing 5.5g of sodium pyrophosphate at 33℃ and cured for 3h to obtain the cured material. Then, molybdenum trioxide and nickel nitrate were dissolved in an aqueous phosphoric acid solution and heated until the raw materials dissolved to form a homogeneous solution, i.e., a Mo-Ni-P solution. 62mL of the Mo-Ni-P solution was used to impregnate the cured material at 40℃ for 6h; the curing time was 5h at 25℃; then, it was dried at 120℃ for 5h and calcined at 420℃ for 3h to obtain the hydrogenation catalyst DC3. The concentrations of Mo, Ni, and P in the hydrogenation-treated catalyst DC3 were uniformly distributed.

[0077] Comparative Example 4

[0078] According to the catalyst preparation method disclosed in patent CN101462080A, 1000g of aluminum hydroxide powder was weighed and extruded into cylindrical strips with a diameter of about 1.7mm and a particle length of 3-4mm using an extruder. The strips were dried at 120℃ for 4 hours and calcined at 900℃ for 4 hours to obtain the carrier DZ.

[0079] 200g of support DZ was weighed and added to deionized water in the following order: tartaric acid, ammonium molybdate, and nickel nitrate. The ratio of the molar amount of tartaric acid to the sum of the molar amounts of molars of molybdate and nickel nitrate was 0.2. The nickel nitrate content was 8.83g, and the ammonium molybdate content was 20.2g. 209ml of deionized water was added, and the mixture was stirred until completely dissolved to obtain an impregnation solution. After thorough mixing, the pH was measured to be 1.5. The support was immersed in the impregnation solution and dried at 80℃ for 6 hours after 120 minutes. Finally, it was calcined in air at 500℃ for 3 hours to obtain the comparative catalyst DC4. The concentrations of Mo, Ni, and P in the hydrogenation-treated catalyst DC4 showed a gradually decreasing trend from the center to the outer surface.

[0080] Table 1. Composition and properties of the catalysts prepared in each example.

[0081] Catalyst number C1 C2 C3 C4 C5 C6 C7 <![CDATA[MoO3,%]]> 22.16 22.10 22.21 22.27 22.19 22.13 22.20 NiO, % 4.13 4.20 4.17 4.12 4.15 4.19 4.11 P，％ 3.28 1.87 3.78 2.81 3.06 2.46 1.22 H / R ratio 0.34 0.76 0.24 0.54 0.62 0.43 0.68 Mo (outer surface) / Mo (center) 0.59 0.68 0.42 0.72 0.53 0.64 0.77 Ni (outer surface) / Ni (center) 0.51 0.60 0.32 0.68 0.44 0.58 0.78 Mo((RH) / 2) / Mo(center) 0.99 1.00 1.01 0.98 0.97 0.99 1.00 Ni((RH) / 2) / Ni(center) 0.98 0.99 0.98 0.99 0.98 0.98 0.97 Mo(H) / Mo(center) 0.97 0.99 0.98 0.99 0.97 0.96 1.00 Ni (at H) / Ni (center) 0.98 0.96 0.95 0.97 0.95 0.98 0.98 Mo(H / 2 place) / Mo(center) 0.79 0.83 0.71 0.86 0.76 0.81 0.88 Ni (at H / 2) / Ni (center) 0.74 0.79 0.65 0.84 0.73 0.78 0.87 P(outer surface) / P(center) 0.86 0.84 0.94 0.79 0.89 0.81 0.76

[0082] Note: In Table 1, the catalyst thickness for the portion with decreasing metal concentration is H, the thickness for the catalyst cross-sectional radius is R, the halfway point of the region with constant metal concentration is (RH) / 2, and the halfway point of the region with decreasing metal concentration is H / 2.

[0083] Continued in Table 1: Composition and properties of catalysts prepared in each example

[0084]

[0085]

[0086] Note: In Table 1, the thickness of the catalyst cross-section radius is R, and the thickness at half the catalyst cross-section radius is R / 2.

[0087] As can be seen from Table 1, the concentration of hydrogenation active metal in the catalyst particles prepared by the method of the present invention shows a trend of first being constant and then decreasing from the center to the outer surface.

[0088] Example 8

[0089] This example is a performance evaluation experiment for the prepared catalyst.

[0090] Catalyst performance evaluation experiments were conducted on a 100ml small-scale hydrogenation unit. Pre-sulfurization of the catalyst was required before the evaluation experiments. The evaluation conditions were: total reaction pressure 16.0 MPa, liquid hourly space velocity 1.5 h⁻¹, hydrogen-to-oil volume ratio 800:1, and reaction temperature 370℃. The properties of the feedstock oil used in the activity evaluation experiments are shown in Table 2, and the performance evaluation results are shown in Table 3.

[0091] Table 2 Properties of Crude Oil

[0092] crude oil VGO <![CDATA[Density (20 °C), g / cm 3 > 0.9369 Distillation range, °C IBP 309 EBP 593 S, wt% 2.74 N, μg / g 1845 (Ni+V), μg / g 64

[0093] The hydrodesulfurization and denitrification activities of the catalyst are expressed as relative to the reference (Comparative Example 1), and the relative hydrodesulfurization activity (RVA(S)) and relative hydrodenitrification activity (RVA(N)) of the catalyst are calculated according to Equations (1) and (2), respectively:

[0094]

[0095]

[0096] In the formula, k(S) and k(N) represent the hydrodesulfurization and hydronitrogenation activities of the catalyst, respectively, and k(DS) and k(DN) represent the hydrodesulfurization and hydronitrogenation activities of the reference agent (Comparative Example 1), respectively. Based on 500 hours of Comparative Example 1, the relative desulfurization and denitrogenation activities are 100%.

[0097] In the formula, Ssp is the sulfur content in the reaction product of the evaluation catalyst used; Ssf is the sulfur content in the reaction feedstock used; Sdp is the sulfur content in the reaction product of the reference reagent; Nsp is the nitrogen content in the reaction product of the evaluation catalyst used; Nsf is the nitrogen mass percentage in the reaction feedstock used; and Ndp is the nitrogen content in the reaction product of the reference reagent.

[0098] Table 3 shows the activity evaluation results of the catalysts obtained in each example.

[0099]

[0100] As shown in Table 3, the catalyst prepared in this invention has higher catalytic activity and better activity stability than the comparative catalyst compared to the comparative catalyst.

Claims

1. A hydrotreating catalyst, comprising a support, a hydrotreating active metal component, and phosphorus, wherein the hydrotreating active metal is a Group VIB metal or a Group VIII metal; wherein, From the center of the catalyst particle cross-section to the outer surface, the concentration of the hydrogenation active metal component shows a distribution trend of first being constant and then decreasing, while the phosphorus concentration shows a distribution trend of gradually decreasing. The catalyst particle cross section refers to the entire surface exposed after cutting along the direction of the smallest dimension of a catalyst particle through the geometric center of its shape. Taking any point on the outermost edge of the catalyst particle's cross-section (i.e., the outer surface) as the starting point and the center point of the catalyst particle's cross-section as the ending point, the straight line segment connecting the starting point and the ending point is the cross-sectional radius R; the thickness of the portion where the concentration of the hydrogenated active metal component decreases is H, that is, the length along the cross-sectional radius from the outer surface to the starting point of the region where the concentration of the hydrogenated active metal component is constant is H; the ratio of H / R is 0.20~0.80; The ratio of the concentration of Group VIII metal component (A1) to the concentration of Group VIB metal component (A2) in the region where the concentration of active metal component in hydrogenation is constant is 0.25 to 0.80; the ratio of the concentration of phosphorus on the outer surface of the catalyst particle cross-section to the concentration of Group VIB metal component (A2) in the region where the concentration of active metal component in hydrogenation is constant is 0.32 to 0.80; and the ratio of the concentration of phosphorus on the outer surface of the catalyst particle cross-section to the concentration at the center is 0.75 to 0.

95.

2. The catalyst according to claim 1, characterized in that, The H / R ratio is 0.24~0.

76.

3. The catalyst according to claim 1, characterized in that, A1 is 0.30~0.75, and A2 is 0.32~0.

75.

4. The catalyst according to claim 1, characterized in that, The ratio of the concentration of Group VIII metal component at half the thickness (H / 2) of the region where the concentration of the hydrogenation active metal component decreases in the cross-section of the catalyst particle to the concentration of Group VIB metal component in the region where the concentration of the hydrogenation active metal component is constant, i.e., B1, is 0.64~0.

88. The ratio of the concentration of Group VIB metal component at half the thickness (H / 2) of the region where the concentration of the hydrogenation active metal component decreases in the cross-section of the catalyst particle to the concentration of Group VIB metal component in the region where the concentration of the hydrogenation active metal component is constant, i.e., B2, is 0.68~0.

8.

5. The catalyst according to claim 4, characterized in that, B1 is 0.65~0.85, and B2 is 0.70~0.

86.

6. The catalyst according to claim 4, characterized in that, B1 is at least 0.08 higher than A1.

7. The catalyst according to claim 6, characterized in that, B1 is 0.10~0.40 higher than A1.

8. The catalyst according to claim 4, characterized in that, B2 is at least 0.10 higher than A2.

9. The catalyst according to claim 8, characterized in that, B2 is 0.10~0.40 higher than A2.

10. The catalyst according to any one of claims 1-9, characterized in that, Among the hydrogenation active metals, the Group VIB metals are Mo and / or W, and the Group VIII metals are Ni and / or Co.

11. The catalyst according to claim 10, characterized in that, Based on the mass of the final hydrogenation catalyst, the mass content of Group VIB metal oxides is 8% to 38%, and the mass content of Group VIII metal oxides is 2% to 10%.

12. The catalyst according to claim 11, characterized in that, Based on the mass of the final hydrogenation catalyst, the mass content of Group VIB metal oxides is 14% to 30%, and the mass content of Group VIII metal oxides is 3% to 7%.

13. The catalyst according to claim 1, characterized in that, The ratio of phosphorus concentration on the outer surface to the center of the catalyst particle cross-section is 0.78 to 0.92; and / or, based on the mass of the catalyst, the phosphorus content, calculated as an element, is 1.0% to 4.0%.

14. The catalyst according to claim 13, characterized in that, Based on the mass of the catalyst, the phosphorus content, calculated as an element, is 1.2% to 3.8% by mass.

15. The catalyst according to claim 1, characterized in that, The carrier is an alumina-based carrier.

16. The catalyst according to claim 15, characterized in that, The carrier has a pore volume of 0.55~1.05mL / g and a specific surface area of ​​170~380m². 2 / g.

17. The catalyst according to claim 1, characterized in that, The catalyst is spherical or columnar.

18. A method for preparing the hydrotreating catalyst according to any one of claims 1-17, comprising the following steps: (1) The carrier is impregnated with an alcohol solution of fatty acid esters and then dried; (2) The dried material obtained in step (1) is soaked in a phosphorus-containing solution and then directly subjected to curing. (3) The cured material obtained in step (2) is immersed in a solution containing hydrogenated active metal components, and then cured, dried and calcined to obtain the hydrogenated catalyst.

19. The method according to claim 18, characterized in that, In step (1), the fatty acid ester is one or more of fatty acid methyl esters with 4 to 18 carbon atoms; the amount of the fatty acid ester is 2.0% to 6.5% of the carrier mass.

20. The method according to claim 19, characterized in that, In step (1), the fatty acid ester is at least one of methyl butyrate, methyl valerate, and methyl oleate; the amount of the fatty acid ester is 2.5% to 6.0% of the carrier mass.

21. The method according to claim 18, characterized in that, In step (1), the alcohol in the alcohol solution is one or more of methanol, ethanol, and propanol, and the amount of the alcohol solution used is 35% to 80% of the saturated water absorption volume of the carrier.

22. The method according to claim 21, characterized in that, In step (1), the amount of alcohol solution used is 40% to 80% of the saturated water absorption volume of the carrier.

23. The method according to claim 18, characterized in that, In step (1), the immersion method of the fatty acid ester alcohol solution is spray immersion, the spray time is 0.5h~5.0h, and the immersion temperature is 15℃~45℃; and / or, the drying temperature in step (1) is 50℃~90℃, and the time is 0.5h~4.0h.

24. The method according to claim 18, characterized in that, In step (1), the immersion method of the fatty acid ester alcohol solution is spray immersion, the spray time is 0.5h~4.0h, and the immersion temperature is 15℃~40℃; and / or, the drying temperature in step (1) is 55℃~85℃, and the time is 0.5h~3.0h.

25. The method according to claim 18, characterized in that, In step (2), the phosphorus source of the phosphorus-containing solution is a compound containing pyrophosphate.

26. The method according to claim 25, characterized in that, In step (2), the phosphorus source of the phosphorus-containing solution is one or more of pyrophosphate, sodium pyrophosphate, and potassium pyrophosphate.

27. The method according to claim 25, characterized in that, In step (2), the mass concentration of phosphorus in the phosphorus-containing solution is 3.0% to 9.0%.

28. The method according to claim 27, characterized in that, In step (2), the mass concentration of phosphorus in the phosphorus-containing solution is 3.2% to 8.5%.

29. The method according to claim 25, characterized in that, In step (2), the amount of phosphorus-containing solution used is 15% to 40% of the volume of water saturated on the carrier.

30. The method according to claim 29, characterized in that, In step (2), the amount of phosphorus-containing solution used is 20% to 40% of the volume of water saturated on the carrier.

31. The method according to claim 18, characterized in that, In step (2), the soaking time is 0.5h~3h, the soaking temperature is 25℃~50℃, the static curing time is 1.0h~6.0h, and the static curing temperature is 15℃~40℃; And / or, in step (3), the immersion is saturated immersion, the immersion time is 0.5h~3h, and the immersion temperature is 20℃~50℃; and / or, the conditioning operation conditions are as follows: conditioning time is 3h~24h; conditioning temperature is 15℃~40℃; And / or, in step (3), the drying conditions are as follows: drying time is 2~10h, drying temperature is 100~160℃; the calcination conditions are as follows: calcination temperature is 380~600℃, calcination time is 2~6h.

32. The use of any one of the catalysts described in claims 1-17 in the hydrotreating of heavy oil feedstocks.

33. The application according to claim 32, characterized in that, The heavy oil feedstock is at least one of vacuum gas oil, coal tar, coal liquefaction oil, catalytic cracking diesel, and catalytic cracking cycle oil.

34. The application according to claim 33, characterized in that, The operating conditions for the hydrogenation treatment are as follows: total reaction pressure 6.0~20.0 MPa, liquid hourly space velocity 0.3~3.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 400:1 to 1800:1, and the reaction temperature is 330℃ to 440℃.

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