Residual oil hydrotreating catalyst grading method and application thereof

Abstract

The invention discloses a grading method and application of a residual oil hydrotreating catalyst. According to the grading method, the characteristics of temperature distribution, material flow distribution, reactant change and the like at different positions of each reactor in the material flow direction can be matched, adaptive catalysts are reasonably arranged, the utilization efficiency of the catalysts is improved, the activity of each catalyst is fully exerted, and the removal effect of sulfides is improved on the basis of controlling the lightening of residual oil.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrogenation, and particularly relates to a grading method of a hydrogenation catalyst and application thereof. Background Art

[0002] In recent years, with the development of international trade and increasingly stringent environmental protection requirements in various countries, the demand for low-sulfur marine fuel has grown exponentially, but supply has always been a problem for the industry.

[0003] Currently, industrial fixed-bed residue oil hydrotreating units generally use a complex multi-catalyst system, which includes a hydrogenation protective agent, a hydrodemetallization catalyst, a hydrodesulfurization catalyst, a hydrodecarbonization catalyst and / or a hydrodenitrogenation catalyst in the direction of the logistics. The grading principle is that the catalyst particle size, pore size, porosity and active metal content are arranged from large to small along the logistics direction.

[0004] Existing technologies can only improve desulfurization efficiency by increasing overall catalyst activity. However, this grading technology lacks desulfurization selectivity, resulting in oversaturation of aromatics and a significant increase in light oil yield. This results in a decrease in the yield of hydrogenated slag that meets the requirements for marine fuel blending components or a lower calorific value, making it unsuitable for producing low-sulfur marine fuel.

[0005] CN101928593A discloses a grading and combination method for heavy oil hydrogenation catalysts. In this method, along the direction of logistics, the catalyst activity gradually increases, the pore size gradually decreases, the particle size gradually decreases, and the porosity gradually decreases; the concentration distribution of the active metal components and acidic additives of the hydrodemetallization catalyst and the hydrodenitrification catalyst is uneven. As the catalyst particles move from the center to the outer surface, the concentration gradient of the active metal components and acidic additives of the hydrodemetallization catalyst decreases, while the concentration gradient of the active metal components and acidic additives of the hydrodenitrification catalyst increases; the concentration of the active metal and acidic additives of the hydrodesulfurization catalyst is uniformly distributed. This method systematically designs the catalyst grading in terms of catalyst pore size, activity, particle size, acidity, etc., thereby comprehensively improving the activity and stability of the catalyst in removing impurities such as metal and carbon residue. However, it lacks selectivity for desulfurization and is not suitable for producing low-sulfur marine fuel.

[0006] CN1259395C discloses a method for loading catalysts for residual oil hydrotreating. This method divides the hydrodenitrogenation reaction zone into multiple beds and employs reverse loading. Specifically, the hydrodenitrogenation catalyst loaded in the downstream catalyst bed has a slightly lower activity than the upstream hydrodenitrogenation catalyst and a slightly larger pore size. This method can slow catalyst carbon deposition, but it also reduces all reaction rates equally and fails to consider the selectivity of the hydrodesulfurization reaction.

[0007] CN109722303A discloses a method for producing low-sulfur marine fuel blending components from high-sulfur heavy oil. This method incorporates a visbreaking and continuous settling unit prior to the residue hydrotreating unit, making it suitable for mass-producing low-sulfur marine fuel blending components from high-sulfur heavy oil. However, this method is complex, requires significant equipment investment, and requires modification of existing residue hydrotreating units.

[0008] In summary, in order to produce high-quality blending components of marine fuel oil without modifying equipment, it is necessary to develop a new production process that can ensure the output of low-sulfur products while suppressing the lightness of the generated oil. Summary of the Invention

[0009] To address the shortcomings of existing technologies, the present invention provides a grading method for residue hydroprocessing catalysts and its application. This grading method can rationally arrange appropriate catalysts based on the temperature distribution, material flow distribution, and reactant variations at different locations in each reactor along the material flow direction, thereby improving catalyst utilization efficiency, fully unleashing the activity of each catalyst, and enhancing sulfide removal while controlling the lightweighting of the residue.

[0010] The present invention provides a grading method for residue oil hydroprocessing catalyst, wherein the grading method comprises at least four hydrogenation reactors connected in series, wherein each reactor is provided with at least two reaction zones from top to bottom.

[0011] According to the present invention, the hydrogenation reactor is a fixed bed hydrogenation reactor.

[0012] According to the present invention, four hydrogenation reactors are used as an example for explanation. According to the logistics direction, they are the first reactor, the second reactor, the third reactor and the fourth reactor. Each reactor is provided with at least two reaction zones from top to bottom, the first reactor is provided with at least the first reaction zone and the second reaction zone, the second reactor is provided with at least the third reaction zone and the fourth reaction zone, the third reactor is provided with at least the fifth reaction zone and the sixth reaction zone, and the fourth reactor is provided with at least the seventh reaction zone and the eighth reaction zone; each reactor is loaded with a hydrogenation catalyst; wherein, the first reaction zone is at least loaded with a hydrogenation protective agent A, the second reaction zone is at least loaded with a hydrodemetallization catalyst B, the third reaction zone is at least loaded with a hydrodemetallization catalyst C, the fourth reaction zone is at least loaded with a hydrodemetallization catalyst D, the fifth reaction zone is at least loaded with a hydrodemetallization catalyst E, the sixth reaction zone is at least loaded with a hydrodesulfurization catalyst F, the seventh reaction zone is at least loaded with a hydrodesulfurization catalyst G, and the eighth reaction zone is at least loaded with a hydrodesulfurization catalyst H.

[0013] According to the present invention, an inactive protective agent may be further loaded on the top of the first reaction zone. The inactive protective agent includes at least one of a bird's nest-shaped, a Raschig ring-shaped, and a porous spherical protective agent.

[0014] According to the present invention, in the hydrogenation reactor, the total acid content of any one hydrogenation catalyst is 0.01 to 3.0 mmol / g, preferably 0.01 to 1.0 mmol / g, and more preferably 0.01 to 0.80 mmol / g. Furthermore, the total acid content of the hydrogenation protectant A is 0.01 to 0.35 mmol / g; the total acid content of the hydrodemetallization catalyst B is 0.03 to 0.35 mmol / g; and the total acid content of the hydrodemetallization catalyst C is 0.05 to 0.40 mmol / g. The total acid content of the hydrodemetallization catalyst D is 0.07 to 0.45 mmol / g. The total acid content of the hydrodemetallization catalyst E is 0.10 to 0.45 mmol / g. The total acid content of the hydrodesulfurization catalyst F is 0.13 to 0.60 mmol / g; the total acid content of the hydrodesulfurization catalyst G is 0.20 to 0.70 mmol / g; and the total acid content of the hydrodesulfurization catalyst H is 0.25 to 0.80 mmol / g.

[0015] According to the present invention, the total acid amount of the hydrogenation catalyst in the first reactor, the second reactor, the third reactor and the fourth reactor gradually increases along the logistics direction; further, in two adjacent reaction zones, the total acid amount of the hydrogenation catalyst in the downstream reaction zone is higher than the total acid amount of the hydrogenation catalyst in its adjacent upstream reaction zone; more preferably, along the logistics direction, the total acid amount of the two adjacent catalysts differs by at least 0.01 to 0.70 mmol / g, preferably 0.02 to 0.25 mmol / g.

[0016] According to the present invention, the Bronsted (i.e. ) The molar ratio of the Bronsted acid amount / Lewis acid amount of the hydrodemetallization catalyst B is 0.15 to 0.40. The molar ratio of the Bronsted acid amount / Lewis acid amount of the hydrodemetallization catalyst C is 0.20 to 0.60. The molar ratio of the Bronsted acid amount / Lewis acid amount of the hydrodemetallization catalyst D is 0.17 to 0.50. The molar ratio of the Bronsted acid amount / Lewis acid amount of the hydrodemetallization catalyst E is 0.12 to 0.35. The molar ratio of the Bronsted acid amount / Lewis acid amount in the hydrodesulfurization catalyst F is less than 0.10, preferably 0.01 to 0.08. The molar ratio of the Bronsted acid amount / Lewis acid amount in the hydrodesulfurization catalyst G is less than 0.10, preferably 0.01 to 0.08. The molar ratio of Bronsted acid content to Lewis acid content in the hydrodesulfurization catalyst H is less than 0.10, preferably 0.01 to 0.08.

[0017] According to the present invention, in the first reaction zone, the second reaction zone, and the third reaction zone, along the direction of logistics, the ratio of the Bronsted acid amount to the total acid amount on the hydrogenation catalyst gradually increases, and the ratio of the Lewis acid amount to the total acid amount gradually decreases. In the third reaction zone, the fourth reaction zone, and the fifth reaction zone, along the direction of logistics, the ratio of the Bronsted acid amount to the total acid amount on each catalyst gradually decreases, and the ratio of the Lewis acid amount to the total acid amount gradually increases. The ratio of the Bronsted acid amount to the total acid amount of the hydrogenation catalyst loaded in the third reaction zone reaches the maximum value of the hydrogenation catalyst loaded in all reaction zones. That is, the molar ratio of the Bronsted acid amount to the Lewis acid amount of the hydrodemetallization catalyst C is greater than the molar ratio of the Bronsted acid amount to the Lewis acid amount of the hydrodemetallization catalyst D.

[0018] According to the present invention, along the logistics direction, the ratio of the Bronsted acid amount on the hydrogenation catalyst in the second reaction zone to the total acid amount is greater than the ratio of the Bronsted acid amount on the adjacent hydrogenation catalyst in the first reaction zone to the total acid amount; the ratio of the Bronsted acid amount on the hydrogenation catalyst in the third reaction zone to the total acid amount is greater than the ratio of the Bronsted acid amount on the adjacent hydrogenation catalyst in the second reaction zone to the total acid amount; the ratio of the Bronsted acid amount on the hydrogenation catalyst in the fourth reaction zone to the total acid amount is less than the ratio of the Bronsted acid amount on the adjacent hydrogenation catalyst in the third reaction zone to the total acid amount; and the ratio of the Bronsted acid amount on the hydrogenation catalyst in the fifth reaction zone to the total acid amount is less than the ratio of the Bronsted acid amount on the adjacent hydrogenation catalyst in the fourth reaction zone to the total acid amount.

[0019] According to the present invention, the activity of the hydrogenation catalysts loaded in each reaction zone increases sequentially along the direction of the flow. Generally, the increase or decrease in the activity of the hydrogenation catalyst can be adjusted by increasing or decreasing the mass content of the active metal in terms of oxide.

[0020] According to the present invention, the volume of the hydrogenation protective agent A loaded in the upper portion of the first reactor accounts for 1% to 70%, preferably 15% to 35%, of the total catalyst loading volume in the first reactor. The volume of the hydrodemetallization catalyst B loaded in the lower portion of the first reactor accounts for 30% to 99%, preferably 65% ​​to 85% of the total catalyst loading volume in the first reactor.

[0021] According to the present invention, the hydrogenation protective agent A comprises a carrier and an active metal component. The active metal comprises one or more Group VIB or Group VIII metals, preferably Mo, or Mo and Ni. Furthermore, the carrier is generally an inorganic oxide; the carrier comprises one or more of aluminum oxide, silicon oxide, calcium oxide, titanium oxide, activated carbon, etc., preferably aluminum oxide and a silicon-aluminum composite carrier. Based on the mass of the hydrogenation protective agent A, molybdenum oxide accounts for 0.5 wt% to 8.5 wt%; nickel oxide accounts for 0 wt% to 2.6 wt%; and the carrier content is 88.9 wt% to 99.5 wt%.

[0022] According to the present invention, the hydrogenation protective agent A can be one or more catalysts. When the hydrogenation protective agent A is a plurality of catalysts, along the logistics direction, the active metal mass content of each catalyst gradually increases, and the total acid content of the catalyst gradually increases. Along the logistics direction, the Q of the downstream catalyst of the adjacent two catalysts is gradually increased. B / Q L Not less than the Q of the upstream catalyst B / Q L , where Q B / Q L is the molar ratio of the Bronsted acid amount / Lewis acid amount of the catalyst.

[0023] According to the present invention, when the hydrogenation protective agent A is loaded in multiple beds, the mass content of the active metal in terms of oxide between two adjacent beds of the hydrogenation protective agent A differs by at least 0.2 percentage points, preferably by at least 0.4 to 5.0 percentage points. Preferably, the mass content of molybdenum oxide differs by at least 0.2 percentage points, preferably by 0.2 to 4.0 percentage points, and the mass content of nickel oxide differs by at least 0.1 percentage points, preferably by 0.2 to 1.0 percentage points.

[0024] According to the present invention, when the hydrogenation protective agent A is loaded in multiple beds, the total acid content of the catalyst between two adjacent catalyst beds should differ by at least 0.01 mmol / g, preferably 0.02 to 0.10 mmol / g.

[0025] According to the present invention, the hydrodemetallization catalyst B comprises a support and an active metal component. The active metal comprises one or more Group VIB or Group VIII metals, preferably Mo and Co. The support is generally an inorganic oxide; the support comprises at least one of aluminum oxide, silicon oxide, calcium oxide, titanium oxide, activated carbon, etc., preferably aluminum oxide and a silicon-aluminum composite support. Based on the mass of the hydrodemetallization catalyst B, the content of molybdenum oxide is 1.0 wt% to 10.5 wt%; the content of cobalt oxide is 0.1 wt% to 3.0 wt%; and the content of the support is 86.5 wt% to 98.9 wt%.

[0026] According to the present invention, the hydrodemetallization catalyst B can be one or more catalysts. When the hydrodemetallization catalyst B is a plurality of catalysts, along the logistics direction, the active metal mass content of each catalyst gradually increases, and the total acid content of the catalyst gradually increases. Along the logistics direction, the Q of the downstream catalyst of the adjacent two catalysts is gradually increased. B / Q L Not less than the Q of the upstream catalyst B / Q L , where Q B / Q L is the molar ratio of the Bronsted acid amount / Lewis acid amount of the catalyst.

[0027] According to the present invention, when the hydrodemetallization catalyst B is loaded in multiple beds, the mass content of the active metal calculated as oxide between two adjacent beds of the hydrodemetallization catalyst B differs by at least 0.5 percentage points, preferably by at least 0.8 to 5.5 percentage points. Preferably, the mass content of molybdenum oxide differs by at least 0.6 percentage points, preferably by 0.6 to 4.5 percentage points, and the mass content of cobalt oxide differs by at least 0.1 percentage point, preferably by 0.2 to 1.0 percentage points.

[0028] According to the present invention, when the hydrodemetallization catalyst B is loaded in multiple beds, the total acid content of the catalyst between two adjacent beds of the hydrodemetallization catalyst B should differ by at least 0.01 mmol / g, preferably 0.02 to 0.10 mmol / g.

[0029] According to the present invention, the volume of the hydrodemetallization catalyst C loaded in the upper portion of the second reactor accounts for 1% to 60%, preferably 20% to 50%, of the total catalyst loading volume in the second reactor. The volume of the hydrodemetallization catalyst D loaded in the lower portion of the second reactor accounts for 40% to 99%, preferably 50% to 80% of the total catalyst loading volume in the second reactor.

[0030] According to the present invention, the hydrodemetallization catalyst C comprises a support and an active metal component. The active metal comprises one or more Group VIB or Group VIII metals, preferably Mo and Co. The support is generally an inorganic oxide; the support comprises at least one of aluminum oxide, silicon oxide, calcium oxide, titanium oxide, activated carbon, etc., preferably aluminum oxide and a silicon-aluminum composite support. Based on the mass of the hydrodemetallization catalyst C, the content of molybdenum oxide is 2.0 wt% to 12.5 wt%; the content of cobalt oxide is 0.2 wt% to 4.3 wt%; and the content of the support is 83.2 wt% to 97.8 wt%.

[0031] According to the present invention, the hydrodemetallization catalyst C can be one or more catalysts. When the hydrodemetallization catalyst C is a plurality of catalysts, along the direction of the flow, the active metal mass content of each catalyst gradually increases, and the total acid content of the catalyst gradually increases. Along the direction of the flow, the Q of the downstream catalyst of the adjacent two catalysts is gradually increased. B / Q L Not less than the Q of the upstream catalyst B / Q L , where Q B / Q L is the molar ratio of the Bronsted acid amount / Lewis acid amount of the catalyst.

[0032] According to the present invention, when the hydrodemetallization catalyst C is loaded in multiple beds, the mass content of the active metal calculated as oxide between two adjacent beds of the hydrodemetallization catalyst C differs by at least 0.5 percentage points, preferably by at least 0.8 to 5.5 percentage points. Preferably, the mass content of molybdenum oxide differs by at least 0.6 percentage points, preferably by 0.6 to 4.5 percentage points, and the mass content of cobalt oxide differs by at least 0.1 percentage point, preferably by 0.2 to 1.0 percentage points.

[0033] According to the present invention, when the hydrodemetallization catalyst C is loaded in multiple beds, the total acid content of the catalyst between adjacent hydrodemetallization catalyst C beds should differ by at least 0.01 mmol / g, preferably 0.02 to 0.10 mmol / g.

[0034] According to the present invention, the hydrodemetallization catalyst D comprises a support and an active metal component. The active metal comprises one or more Group VIB or Group VIII metals, preferably Mo and Co. The support is generally an inorganic oxide; the support comprises at least one of aluminum oxide, silicon oxide, calcium oxide, titanium oxide, activated carbon, etc., preferably aluminum oxide and a silicon-aluminum composite support. Based on the mass of the hydrodemetallization catalyst D, the content of molybdenum oxide is 3.0 wt% to 14.5 wt%; the content of cobalt oxide is 0.3 wt% to 5.0 wt%; and the content of the support is 80.5 wt% to 96.7 wt%.

[0035] According to the present invention, the hydrodemetallization catalyst D can be one or more catalysts. When the hydrodemetallization catalyst D is a plurality of catalysts, along the logistics direction, the active metal mass content of each catalyst gradually increases, and the total acid content of the catalyst gradually increases. Along the logistics direction, the Q of the downstream catalyst of the adjacent two catalysts is gradually increased. B / Q L Not greater than the Q of the upstream catalyst B / Q L , where Q B / Q Lis the molar ratio of the Bronsted acid amount / Lewis acid amount of the catalyst.

[0036] According to the present invention, when the hydrodemetallization catalyst D is loaded in multiple beds, the mass content of the active metal calculated as oxide between two adjacent beds of the hydrodemetallization catalyst D differs by at least 0.5 percentage points, preferably by at least 0.8 to 5.5 percentage points. Preferably, the mass content of molybdenum oxide differs by at least 0.6 percentage points, preferably by 0.6 to 4.5 percentage points, and the mass content of cobalt oxide differs by at least 0.1 percentage point, preferably by 0.2 to 1.0 percentage points.

[0037] According to the present invention, when the hydrodemetallization catalyst D is loaded in multiple beds, the total acid content of the catalyst between adjacent hydrodemetallization catalyst D beds should differ by at least 0.01 mmol / g, preferably 0.01 to 0.10 mmol / g.

[0038] According to the present invention, the volume of the hydrodemetallization catalyst E loaded in the upper portion of the third reactor accounts for 1% to 50%, preferably 20% to 40%, of the total volume of the third reactor. The volume of the hydrodesulfurization catalyst F loaded in the lower portion of the third reactor accounts for 50% to 99%, preferably 60% to 80% of the total volume of the third reactor.

[0039] According to the present invention, the hydrodemetallization catalyst E comprises a support and an active metal component. The active metal comprises one or more Group VIB or Group VIII metals, preferably Mo and Co. The support is generally an inorganic oxide; the support comprises at least one of aluminum oxide, silicon oxide, calcium oxide, titanium oxide, activated carbon, etc., preferably aluminum oxide and a silicon-aluminum composite support. Based on the mass of the hydrodemetallization catalyst E, the content of molybdenum oxide is 4.0 wt% to 16.5 wt%; the content of cobalt oxide is 0.5 wt% to 5.7 wt%; and the content of the support is 77.8 wt% to 95.5 wt%.

[0040] According to the present invention, the hydrodemetallization catalyst E can be one or more catalysts. When the hydrodemetallization catalyst E is a plurality of catalysts, along the direction of the flow, the active metal mass content of each catalyst gradually increases, and the total acid content of the catalyst gradually increases. Along the direction of the flow, the Q of the downstream catalyst of the adjacent two catalysts is gradually increased. B / Q L Not greater than the Q of the upstream catalyst B / Q L , where Q B / Q L is the molar ratio of the Bronsted acid amount / Lewis acid amount of the catalyst.

[0041] According to the present invention, when the hydrodemetallization catalyst E is loaded in multiple beds, the mass content of the active metal calculated as oxide between two adjacent beds of the hydrodemetallization catalyst E differs by at least 1.0 percentage point, preferably by at least 1.0 to 5.5 percentage points. Preferably, the mass content of molybdenum oxide differs by at least 0.8 percentage point, preferably by 0.8 to 4.5 percentage points, and the mass content of cobalt oxide differs by at least 0.1 percentage point, preferably by 0.2 to 1.0 percentage point.

[0042] According to the present invention, when the hydrodemetallization catalyst E is loaded in multiple beds, the total acid content of the catalyst between adjacent hydrodemetallization catalyst E beds should differ by at least 0.02 mmol / g, preferably 0.02 to 0.10 mmol / g.

[0043] According to the present invention, the hydrodesulfurization catalyst F comprises a support and an active metal component. The active metal comprises one or more Group VIB or Group VIII metals, preferably Mo and Ni. The support is generally an inorganic oxide; the support comprises at least one of aluminum oxide, silicon oxide, calcium oxide, titanium oxide, activated carbon, etc., preferably aluminum oxide and a silicon-aluminum composite support. Based on the mass of Catalyst F, the content of molybdenum oxide is 7.5 wt% to 22.0 wt%, the content of nickel oxide is 1.0 wt% to 6.2 wt%, and the content of the support is 71.8 wt% to 91.5 wt%.

[0044] According to the present invention, the hydrodesulfurization catalyst F can be one or more catalysts. When the hydrodesulfurization catalyst F is a plurality of catalysts, along the flow direction, the active metal mass content of each catalyst gradually increases, and the total acid content of the catalyst gradually increases. B / Q L Maintained below 0.10, preferably below 0.08, where Q B / Q L is the molar ratio of the Bronsted acid amount / Lewis acid amount of the catalyst.

[0045] According to the present invention, when the hydrodesulfurization catalyst F is loaded in multiple beds, the mass content of active metals in terms of oxides between two adjacent beds of hydrodesulfurization catalyst F differs by at least 1.0 percentage point, preferably by at least 1.0 to 6.0 percentage points. Preferably, the mass content of nickel oxide differs by at least 0.8 percentage point, preferably by 0.8 to 5.0 percentage points, and the mass content of nickel oxide differs by at least 0.1 percentage point, preferably by 0.2 to 1.0 percentage point.

[0046] According to the present invention, when the hydrodesulfurization catalyst F is loaded in multiple beds, the total acid content of the catalyst between two adjacent hydrodesulfurization catalyst F beds should differ by at least 0.02 mmol / g, preferably 0.04 to 0.10 mmol / g.

[0047] According to the present invention, the volume of the hydrodesulfurization catalyst G loaded in the upper portion of the fourth reactor accounts for 50% to 99%, preferably 50% to 70%, of the total catalyst loading volume in the fourth reactor. The volume of the hydrodesulfurization catalyst H loaded in the lower portion of the fourth reactor accounts for 1% to 50%, preferably 30% to 50%, of the total catalyst loading volume in the fourth reactor.

[0048] According to the present invention, the hydrodesulfurization catalyst G comprises a support and an active metal component. The active metal comprises one or more Group VIB or Group VIII metals, preferably Mo and Ni. The support is generally an inorganic oxide; the support comprises at least one of aluminum oxide, silicon oxide, calcium oxide, titanium oxide, activated carbon, etc., preferably aluminum oxide and a silicon-aluminum composite support. Preferably, the hydrodesulfurization catalyst G comprises, based on the mass of the hydrodesulfurization catalyst G, 8.5 wt% to 25.0 wt% of molybdenum oxide, 2.0 wt% to 7.5 wt% of nickel oxide, and 67.5 wt% to 89.5 wt% of the support.

[0049] According to the present invention, the hydrodesulfurization catalyst G can be one or more catalysts. When the hydrodesulfurization catalyst G is a plurality of catalysts, along the direction of the flow, the active metal mass content of each catalyst gradually increases, and the total acid content of the catalyst gradually increases. B / Q L Maintained below 0.10, preferably below 0.08, where Q B / Q L is the molar ratio of the Bronsted acid amount / Lewis acid amount of the catalyst.

[0050] According to the present invention, when the hydrodesulfurization catalyst G is loaded in multiple beds, the mass content of active metals in terms of oxides between two adjacent beds of hydrodesulfurization catalyst G differs by at least 1.3 percentage points, preferably by at least 1.3 to 6.0 percentage points. Preferably, the mass content of molybdenum oxide differs by at least 1.1 percentage points, at least 1.1 to 5.0 percentage points, and the mass content of nickel oxide differs by at least 0.1 percentage point, at least 0.2 to 1.0 percentage points.

[0051] According to the present invention, when the hydrodesulfurization catalyst G is loaded in multiple beds, the total acid content of the catalyst between adjacent hydrodesulfurization catalyst G beds should differ by at least 0.01 mmol / g, preferably 0.02 to 0.10 mmol / g.

[0052] According to the present invention, the hydrodesulfurization catalyst H comprises a support and an active metal component. The active metal comprises one or more Group VIB or Group VIII metals, preferably Mo and Co. The support is generally an inorganic oxide; the support comprises at least one of aluminum oxide, silicon oxide, calcium oxide, titanium oxide, activated carbon, etc., preferably aluminum oxide and a silicon-aluminum composite support. Based on the mass of the hydrodesulfurization catalyst H, the content of molybdenum oxide is 8.5 wt% to 25.0 wt%, the content of cobalt oxide is 2.0 wt% to 7.5 wt%, and the content of the support is 67.5 wt% to 89.5 wt%.

[0053] According to the present invention, the hydrodesulfurization catalyst H can be one or more catalysts. When the hydrodesulfurization catalyst H is a plurality of catalysts, along the flow direction, the active metal mass content of each catalyst gradually increases, and the total acid content of the catalyst gradually increases. B / Q L Maintained below 0.10, preferably below 0.08, where Q B / Q L is the molar ratio of the Bronsted acid amount / Lewis acid amount of the catalyst.

[0054] According to the present invention, when the hydrodesulfurization catalyst H is loaded in multiple beds, the mass content of active metals in two adjacent beds of hydrodesulfurization catalyst H, calculated as oxides, differs by at least 1.3 percentage points, preferably by at least 1.3 to 6.0 percentage points. Preferably, the mass content of molybdenum oxide differs by at least 1.1 percentage points, at least 1.1 to 5.0 percentage points, and the mass content of cobalt oxide differs by at least 0.1 percentage point, at least 0.2 to 1.0 percentage points.

[0055] According to the present invention, when the hydrodesulfurization catalyst H is loaded in multiple beds, the total acid content of the catalyst between two adjacent beds of hydrodesulfurization catalyst H differs by at least 0.02 mmol / g, preferably 0.04 to 0.10 mmol / g.

[0056] According to the present invention, the hydrogenation catalyst (hydrogenation protective agent A, hydrodemetallization catalyst B, hydrodemetallization catalyst C, hydrodemetallization catalyst D, hydrodemetallization catalyst E, hydrodesulfurization catalyst F, hydrodesulfurization catalyst G, hydrodesulfurization catalyst H) can be selected from commercial catalysts conventional in the art or catalysts prepared by conventional methods. The acidity of the hydrogenation catalyst of the present invention, including the total acid content and the molar ratio of Bronsted acid / Lewis acid, can be adjusted by the preparation process of the support. For example, a composite oxide can be used as a support, and the acid properties of the catalyst can be changed by the ratio of different oxides (for example, using a SiO2-Al2O3 composite support, the acid properties can be adjusted by the silicon-aluminum mass ratio). For another example, the acidity can be adjusted by adding an inorganic auxiliary agent to the support raw material or during the support preparation process. The auxiliary agent can be one or more, preferably containing at least one of boron, phosphorus, chlorine, fluorine, lanthanum, cerium, titanium, etc. An organic auxiliary agent can also be added in an appropriate amount as needed during the support preparation process, and the organic auxiliary agent can be one or more of citric acid, oxalic acid, and tartaric acid. Another example is that the acidity can be adjusted by the support pretreatment temperature. Commercial catalysts can use the FGF and FZC series commercial hydrogenation catalysts developed by Dalian Petrochemical Research Institute: FGF-01, FGF-02, FZC-100, FZC-100B, FZC-1000, FZC-1011, FZC-1012, FZC-1013, FZC-12B, FZC-102, FZC-102A, FZC-102B, FZC-102K, FZC-102N, FZC-103, FZC-103A, FZC-13B, FZC-103D, FZ C-103E, FZC-105, FZC-106, FZC-1MN, FZC-2MN, FZC-3MN, FZC-28, FZC-28A, FZC-28B, FZC-2021, FZC-2031, FZC-204A , FZC-204, FZC-204B, FZC-33B, FZC-33BT, FZC-34B, FZC-34BT, FZC-41A, FZC-41B, FZC-41BT, FZC-3011, FZC-4011, etc.

[0057] According to the present invention, a hydrogenation protective agent may be added before the hydrodemetallization catalyst C in the second reactor.

[0058] According to the present invention, a hydrogenation protective agent may be added before the hydrodemetallization catalyst E in the third reactor.

[0059] According to the present invention, a hydrogenation protective agent may be loaded before the hydrodesulfurization catalyst G in the fourth reactor.

[0060] According to the present invention, the shape of each catalyst can be spherical, quasi-spherical, cylindrical, Raschig ring, multi-impeller, strip, clover or four-leaf clover, etc.

[0061] According to the present invention, the catalyst loading volume ratio of the first hydrogenation reactor, the second hydrogenation reactor, the third hydrogenation reactor and the fourth hydrogenation reactor is conventionally loaded, preferably, (0.6-1.0):(0.6-1.0):(0.6-1):1.

[0062] According to the present invention, the grading method can further add at least one reactor on the basis of the above-mentioned four fixed-bed hydrogenation reactors. Preferably, at least one reactor is added between the third reactor and the fourth reactor, and preferably 2-3 reactors are added. According to the logistics direction, it is called the third plus N reactor, and N is 1 to 3. For example, when N=1, the added reactor is the third plus one reactor. When N=2, the added reactors are the third plus one reactor and the third plus two reactors in sequence. When N=3, the added reactors are the third plus one reactor, the third plus two reactors, and the third plus three reactors in sequence. Among them, the third plus N reactor will no longer be divided into regions. The catalyst loaded in the third plus N reactor is a hydrodesulfurization catalyst, and its grading principle is that the catalyst activity gradually increases along the logistics direction, and the total acid amount of each catalyst gradually increases. Preferably, the total acid amount of each catalyst increases by 0.01 to 0.70 mmol / g in sequence along the logistics direction, and more preferably increases by 0.02 to 0.25 mmol / g in sequence. The hydrodesulfurization catalyst loaded in the third plus N reactor basically only contains Lewis acid, and the Bronsted acid content is relatively low. Q B / Q L remains below 0.10, where Q B / Q L The increase or decrease in activity of each catalyst can be adjusted by increasing or decreasing the mass content of the active metal as oxide.

[0063] According to the present invention, the hydrogenation catalyst loaded into the third N-addition reactor comprises a support and an active metal component. Preferably, the active components of the hydrogenation catalyst are Mo and Ni. The mass content of the active metals, calculated as oxides, between two adjacent hydrogenation catalyst beds differs by at least 1.0 percentage point, preferably by at least 1.0 to 6.5 percentage points. Preferably, the mass content of molybdenum oxide differs by at least 0.8 percentage point, preferably by at least 1.0 to 5.0 percentage points, and the mass content of nickel oxide differs by at least 0.2 percentage point, preferably by at least 0.2 to 1.5 percentage points.

[0064] In the present invention, the grading principles not mentioned above are the same as those of conventional residue oil hydrogenation catalysts, such as the grading principles of particle size, pore volume, and pore diameter: the particle size, pore volume, and pore diameter of each catalyst decrease in sequence along the direction of logistics.

[0065] The second aspect of the present invention provides application of the catalyst grading method in residual oil hydroprocessing.

[0066] According to the present invention, residual oil feedstock and hydrogen are fed from the top of the first reactor, and after contacting and reacting with the catalyst in the first reactor, the resulting stream enters the second reactor from the top of the second reactor, and after contacting and reacting with the catalyst in the second reactor, the resulting stream enters the third reactor from the top of the third reactor, and after contacting and reacting with the catalyst in the third reactor, the resulting stream enters the fourth reactor from the top of the fourth reactor, and after contacting and reacting with the catalyst in the fourth reactor, a low-sulfur marine fuel oil blending component is obtained.

[0067] According to the present invention, the residual oil raw material can be at least one of atmospheric residual oil and vacuum residual oil. The residual oil raw material can also be blended with at least one of catalytic cracking slurry, coal tar, coker gas oil, and coker diesel.

[0068] According to the present invention, preferably, the properties of the residual oil feedstock are as follows: the mass content of sulfur is 1.0% to 5.0%, preferably 2.0% to 4.0%; the mass content of nitrogen is ≤4000 ppm, preferably ≤3200 ppm; the mass content of metal impurities, calculated as Ni and V, is ≤200 ppm, preferably 10 to 100 ppm, further 20 to 80 ppm; the mass content of residual carbon is 8.0% to 20.0%, preferably 10.0% to 14.0%.

[0069] According to the present invention, the reaction conditions of the hydrogenation are as follows: the reaction hydrogen partial pressure is 15.0-20.0 MPa; the liquid hourly volume space velocity is 0.15-0.25 h -1 The hydrogen-to-oil volume ratio at the reactor inlet is 400-1000:1. The average catalyst bed temperature in each reactor is 350-380°C for the first reactor, 360-395°C for the second reactor, 370-400°C for the third reactor, and 375-410°C for the fourth reactor. The average catalyst bed temperature in the downstream reactor is higher than that in the upstream reactor along the logistics direction. Furthermore, the average catalyst bed temperature difference between adjacent reactors in the first, second, and third reactors is 5-17°C; the average catalyst bed temperature difference between the third and fourth reactors is 3-12°C.

[0070] According to the present invention, the properties of the low-sulfur marine fuel oil blending component are: the mass content of sulfur is ≤0.5wt%.

[0071] Compared with the prior art, the advantages of the method of the present invention are:

[0072] The grading method of the present invention rationally distributes the reaction load of each reaction zone. In view of the changes in the composition and diffusion properties of reactants in different reaction zones, as well as the different characteristics of temperature and hydrogen partial pressure, the temperature gradient and desulfurization reaction path of each reactor are rationalized through the design of the catalyst acid amount and acid type and intrinsic activity (different active metals and their contents) in each reaction zone, thereby achieving the purpose of deep desulfurization and improving desulfurization selectivity, controlling aromatic saturation and inhibiting excessive cracking, retaining high calorific value components in the product oil, and producing qualified low-sulfur marine fuel blending components. DETAILED DESCRIPTION

[0073] The technical solutions of the present invention are further described below with reference to the following embodiments, but are not limited to the following embodiments.

[0074] The present invention, the device used in the embodiment is a fixed-bed hydroprocessing experimental device. Four fixed-bed reactors are arranged in series on the device. The four reactors are the first reactor (first reactor), the second reactor (second reactor), the third reactor (third reactor), and the fourth reactor (fourth reactor) in the direction of logistics. Each reactor is provided with two reaction zones from top to bottom. That is, the first reaction zone and the second reaction zone are provided in the first reactor, the third reaction zone and the fourth reaction zone are provided in the second reactor, the fifth reaction zone and the sixth reaction zone are provided in the third reactor, and the seventh reaction zone and the eighth reaction zone are provided in the fourth reactor; each reactor is loaded with a hydrogenation catalyst; wherein, the first reaction zone is loaded with a hydrogenation protective agent A, the second reaction zone is loaded with a hydrodemetallization catalyst B, the third reaction zone is loaded with a hydrodemetallization catalyst C, the fourth reaction zone is loaded with a hydrodemetallization catalyst D, the fifth reaction zone is loaded with a hydrodemetallization catalyst E, the sixth reaction zone is loaded with a hydrodesulfurization catalyst F, the seventh reaction zone is loaded with a hydrodesulfurization catalyst G, and the eighth reaction zone is loaded with a hydrodesulfurization catalyst H.

[0075] In the present invention, the Examples and Comparative Examples, residual oil was used as the feedstock oil, and the feedstock oil used in each example was identical. The properties of the feedstock oil are shown in Table 1.

[0076] The overall process conditions in the present invention, the examples, and the comparative examples are the same. The hydrogenation reaction process conditions are shown in Table 2. In each reactor, the flow direction is from top to bottom.

[0077] In the present invention, the acidity of the hydrogenation catalyst in each example is adjusted by adding an auxiliary agent to the carrier raw material or during the carrier preparation process.

[0078] In the present invention, the hydrogenation catalysts A, B, C, D, E, F, G, and H in the examples are represented by letters plus numbers, for example, A1, A2, B1, B2, C1, and C2.

[0079] In the present invention, the catalyst loading volume ratio of the first reaction: the second reaction: the third reaction: the fourth reaction in the embodiment and the comparative example is 1:1:1:1.

[0080] In the present invention, the total acidity, Bronsted acidity and Lewis acidity of the catalyst are measured by gravimetric adsorption infrared spectroscopy using pyridine as an adsorbent. The total acidity is the sum of the Bronsted acidity and the Lewis acidity.

[0081] Table 1 Properties of crude oil

[0082] project nature <![CDATA[Density (20 °C), kg / m 3 > 998 <![CDATA[Viscosity (100 °C), mm 2 / s]]> 260 Sulfur, wt% 3.32 Nitrogen, μg / g 3008 Metal Ni+V, μg / g 76 Carbon residue, wt% 11.2 Four components, wt% Saturation 31.4 Aroma 43.7 colloid 21.9 Asphaltene 3.0

[0083] Table 2 Hydrogenation reaction process conditions

[0084] Reaction hydrogen partial pressure / MPa 15 <![CDATA[Liquid hourly space velocity / h -1 > 0.20 Hydrogen-to-oil volume ratio 650：1 Average bed temperature / ℃ A reversal 360 Second anti 370 Three Antis 380 Four Anti- 390

[0085] Table 3 Physicochemical parameters of hydrogenation catalysts in various examples

[0086]

[0087]

[0088] Example 1

[0089] The catalyst loading scheme of this example is shown in Table 4.

[0090] Table 4 Catalyst loading scheme along the logistics direction

[0091]

[0092] Example 2

[0093] The catalyst loading scheme of this example is shown in Table 5.

[0094] Table 5 Catalyst loading scheme along the logistics direction

[0095]

[0096] Example 3

[0097] The catalyst loading scheme of this example is shown in Table 6.

[0098] Table 6 Catalyst loading scheme along the logistics direction

[0099]

[0100] Example 4

[0101] The only difference from Example 1 is the different gradation relationship of the active metals loaded in the first, second, third, and fourth reactors. The loading scheme of the catalyst in this example is shown in Table 7.

[0102] Table 7 Catalyst loading scheme along the logistics direction

[0103]

[0104]

[0105] Comparative Example 1

[0106] The difference from Example 4 is that the gradation relationship between B acid and L acid is different. The catalyst and loading scheme of this example are shown in Tables 8 and 9.

[0107] Table 8 Physicochemical parameters of the hydrogenation catalyst of Comparative Example 1

[0108]

[0109] Table 9 Catalyst loading scheme along the logistics direction of Comparative Example 1

[0110]

[0111] Comparative Example 2

[0112] The catalyst and loading scheme of this example are shown in Tables 10 and 11.

[0113] Table 10 Physicochemical parameters of hydrogenation catalyst

[0114]

[0115] Table 11 Catalyst loading scheme along the logistics direction

[0116]

[0117] Comparative Example 3

[0118] The catalyst and its gradation relationship are based on Example 1 of 201410541861.0. The first reactor is loaded with hydrogenation protective agent G1, the second reactor is loaded with hydrodemetallization catalyst M1, the third reactor is loaded with hydrodesulfurization catalyst S1, and the fourth reactor is loaded with hydrodenitrogenation catalyst N1. The feedstock oil of Table 1 and the hydrogenation reaction process conditions of Table 2 are used.

[0119] Test Case

[0120] When the unit started operating, the feedstock oil and hydrogen entered the first reactor, followed by the second, third, and fourth reactors. The reactions were run for 1000 hours. The impurity removal results for each reaction are shown in Table 12.

[0121] Table 12 Comparison of reaction effects between examples and comparative examples

[0122]

[0123] As can be seen from the above examples and comparative examples, the sulfur content of the hydrogenated product in the examples reaches below 0.5%, while the residual carbon rate is guaranteed to be below 55%. Comparative Example 2 uses a Mo-Co type catalyst and the catalyst acid properties are distributed according to conventional gradation, so the hydrodesulfurization and residual carbon removal rates are both low, and the desulfurization effect does not meet the index requirements. Comparative Example 1 uses a Mo-Ni type catalyst and the catalyst acid properties are distributed according to conventional gradation, so the hydrodesulfurization and residual carbon removal rates are both high. Although the product sulfide index meets the requirements, the desulfurization selectivity is low, the product is over-reacted, and the content of heavy components such as aromatics, gums and asphaltene is low, which cannot retain the heavy components that are beneficial as marine fuel oil. The catalyst application test results of Comparative Example 3 of the prior art also cannot meet the requirements.

[0124] This demonstrates that the catalyst grading method provided by the present invention can significantly improve desulfurization selectivity in the production of low-sulfur marine fuel blending components through residual oil hydroprocessing. While maintaining the product sulfur content, it also reduces the carbon removal rate, inhibiting cracking reactions and aromatic saturation reactions, retaining more heavy components, and improving the fuel's calorific value.

Claims

1. A grading method for a residue hydrotreating catalyst, wherein: The grading method comprises at least four hydrogenation reactors connected in series, which are, in order of logistics direction, a first reactor, a second reactor, a third reactor and a fourth reactor; Each reactor is provided with at least two reaction zones from top to bottom, wherein the first reactor is provided with at least the first reaction zone and the second reaction zone, the second reactor is provided with at least the third reaction zone and the fourth reaction zone, the third reactor is provided with at least the fifth reaction zone and the sixth reaction zone, and the fourth reactor is provided with at least the seventh reaction zone and the eighth reaction zone; each reactor is loaded with a hydrogenation catalyst; wherein the first reaction zone is loaded with at least a hydrogenation protective agent A, the second reaction zone is loaded with at least a hydrodemetallization catalyst B, the third reaction zone is loaded with at least a hydrodemetallization catalyst C, the fourth reaction zone is loaded with at least a hydrodemetallization catalyst D, the fifth reaction zone is loaded with at least a hydrodemetallization catalyst E, the sixth reaction zone is loaded with at least a hydrodesulfurization catalyst F, the seventh reaction zone is loaded with at least a hydrodesulfurization catalyst G, and the eighth reaction zone is loaded with at least a hydrodesulfurization catalyst H; The total acid content of the hydrogenation catalyst gradually increases along the logistics direction in the first reactor, the second reactor, the third reactor and the fourth reactor; In the first reaction zone, the second reaction zone, and the third reaction zone, along the flow direction, the proportion of Bronsted acid in the total acid content on the hydrogenation catalyst gradually increases, and the proportion of Lewis acid in the total acid content gradually decreases; In the third reaction zone, the fourth reaction zone, and the fifth reaction zone, the proportion of the Bronsted acid content in the total acid content on each catalyst gradually decreases along the logistics direction, and the proportion of the Lewis acid content in the total acid content gradually increases.

2. The method according to claim 1, characterized in that The active metal in the hydrogenation protective agent A is Mo, or Mo and Ni; further preferably, based on the mass of the hydrogenation protective agent A, molybdenum oxide accounts for 0.5wt% to 8.5wt%; nickel oxide accounts for 0wt% to 2.6wt%; The active metals in the hydrodemetallization catalyst B are Mo and Co. More preferably, based on the mass of the hydrodemetallization catalyst B, the content of molybdenum oxide is 1.0 wt% to 10.5 wt%; the content of cobalt oxide is 0.1 wt% to 3.0 wt%; The active metals in the hydrodemetallization catalyst C are Mo and Co. More preferably, based on the mass of the hydrodemetallization catalyst C, the content of molybdenum oxide is 2.0 wt% to 12.5 wt%; the content of cobalt oxide is 0.2 wt% to 4.3 wt%; The active metals in the hydrodemetallization catalyst D are Mo and Co. More preferably, based on the mass of the hydrodemetallization catalyst D, the content of molybdenum oxide is 3.0 wt% to 14.5 wt%; the content of cobalt oxide is 0.3 to 5.0 wt%; The active metals in the hydrodemetallization catalyst E are Mo and Co. More preferably, based on the mass of the hydrodemetallization catalyst E, the content of molybdenum oxide is 4.0 wt% to 16.5 wt%; the content of cobalt oxide is 0.5 wt% to 5.7 wt%; The active metals in the hydrodesulfurization catalyst F are Mo and Ni; further preferably, based on the mass of the catalyst F, the content of molybdenum oxide is 7.5wt% to 22.0wt%, and the content of nickel oxide is 1.0wt% to 6.2wt%; The active metals in the hydrodesulfurization catalyst G are Mo and Ni; further preferably, the hydrodesulfurization catalyst G has a molybdenum oxide content of 8.5 wt% to 25.0 wt% and a nickel oxide content of 2.0 wt% to 7.5 wt% based on the mass of the hydrodesulfurization catalyst G. The active metals in the hydrodesulfurization catalyst H are Mo and Co. More preferably, based on the mass of the hydrodesulfurization catalyst H, the content of molybdenum oxide is 8.5 wt% to 25.0 wt%, and the content of cobalt oxide is 2.0 wt% to 7.5 wt%.

3. The method according to claim 1, characterized in that The molar ratio of Bronsted acid amount / Lewis acid amount of the hydrogenation protective agent A is 0.10 to 0.30; The molar ratio of Bronsted acid amount / Lewis acid amount of the hydrodemetallization catalyst B is 0.15 to 0.40; The molar ratio of Bronsted acid amount / Lewis acid amount of the hydrodemetallization catalyst C is 0.20 to 0.60; The molar ratio of Bronsted acid amount / Lewis acid amount of the hydrodemetallization catalyst D is 0.17 to 0.50; The molar ratio of Bronsted acid amount / Lewis acid amount of the hydrodemetallization catalyst E is 0.12 to 0.35; The molar ratio of Bronsted acid to Lewis acid in the hydrodesulfurization catalyst F is less than 0.10, preferably 0.01 to 0.08; The molar ratio of Bronsted acid to Lewis acid in the hydrodesulfurization catalyst G is less than 0.10, preferably 0.01 to 0.08; The molar ratio of Bronsted acid content to Lewis acid content in the hydrodesulfurization catalyst H is less than 0.10, preferably 0.01 to 0.

08.

4. The method according to any one of claims 1 to 3, characterized in that: The hydrogenation protective agent A is one or more catalysts; when the hydrogenation protective agent A is multiple catalysts, along the logistics direction, the active metal mass content of each catalyst gradually increases, and the total acid content of the catalyst gradually increases; When the hydrogenation protective agent A is loaded in multiple beds, the mass content of the active metals calculated as oxides between two adjacent beds of the hydrogenation protective agent A differs by at least 0.2 percentage points, preferably by at least 0.4 to 5.0 percentage points. Preferably, the mass content of molybdenum oxide differs by at least 0.2 percentage points, preferably by 0.2 to 4.0 percentage points, and the mass content of nickel oxide differs by at least 0.1 percentage points, preferably by 0.2 to 1.0 percentage points. When the hydrogenation protective agent A is loaded in multiple beds, the total acid content of the catalyst between two adjacent catalyst beds should differ by at least 0.01 mmol / g, preferably 0.02 to 0.10 mmol / g.

5. The method according to any one of claims 1 to 3, characterized in that: The hydrodemetallization catalyst B is one or more catalysts; when the hydrodemetallization catalyst B is multiple catalysts, along the logistics direction, the active metal mass content of each catalyst gradually increases, and the total acid content of the catalyst gradually increases; When the hydrodemetallization catalyst B is loaded in multiple beds, the mass content of the active metal calculated as oxide between two adjacent beds of the hydrodemetallization catalyst B differs by at least 0.5 percentage points, preferably by at least 0.8 to 5.5 percentage points. Preferably, the mass content of molybdenum oxide differs by at least 0.6 percentage points, preferably by 0.6 to 4.5 percentage points, and the mass content of cobalt oxide differs by at least 0.1 percentage point, preferably by 0.2 to 1.0 percentage points. When the hydrodemetallization catalyst B is loaded in multiple beds, the total acid content of the catalyst between two adjacent beds of hydrodemetallization catalyst B should differ by at least 0.01 mmol / g, preferably 0.02 to 0.10 mmol / g.

6. The method according to any one of claims 1 to 3, characterized in that: The hydrodemetallization catalyst C is one or more catalysts; when the hydrodemetallization catalyst C is multiple catalysts, along the logistics direction, the active metal mass content of each catalyst gradually increases, and the total acid content of the catalyst gradually increases; When the hydrodemetallization catalyst C is loaded in multiple beds, the mass content of the active metal calculated as oxide between two adjacent beds of the hydrodemetallization catalyst C differs by at least 0.5 percentage points, preferably by at least 0.8 to 5.5 percentage points. Preferably, the mass content of molybdenum oxide differs by at least 0.6 percentage points, preferably by 0.6 to 4.5 percentage points, and the mass content of cobalt oxide differs by at least 0.1 percentage point, preferably by 0.2 to 1.0 percentage points. When the hydrodemetallization catalyst C is loaded in multiple beds, the total acid content of the catalyst between adjacent hydrodemetallization catalyst C beds should differ by at least 0.01 mmol / g, preferably 0.02 to 0.10 mmol / g.

7. The method according to any one of claims 1 to 3, characterized in that: The hydrodemetallization catalyst D is one or more catalysts; when the hydrodemetallization catalyst D is multiple catalysts, along the logistics direction, the active metal mass content of each catalyst gradually increases, and the total acid content of the catalyst gradually increases; When the hydrodemetallization catalyst D is loaded in multiple beds, the mass content of the active metal calculated as oxide between two adjacent beds of the hydrodemetallization catalyst D differs by at least 0.5 percentage points, preferably by at least 0.8 to 5.5 percentage points. Preferably, the mass content of molybdenum oxide differs by at least 0.6 percentage points, preferably by 0.6 to 4.5 percentage points, and the mass content of cobalt oxide differs by at least 0.1 percentage point, preferably by 0.2 to 1.0 percentage points. When the hydrodemetallization catalyst D is loaded in multiple beds, the total acid content of the catalyst between adjacent beds of hydrodemetallization catalyst D should differ by at least 0.01 mmol / g, preferably 0.01 to 0.10 mmol / g.

8. The method according to any one of claims 1 to 3, characterized in that: The hydrodemetallization catalyst E is one or more catalysts; when the hydrodemetallization catalyst E is a plurality of catalysts, along the flow direction, the active metal mass content of each catalyst gradually increases, and the total acid content of the catalyst gradually increases; When the hydrodemetallization catalyst E is loaded in multiple beds, the mass content of the active metal calculated as oxide between two adjacent beds of the hydrodemetallization catalyst E differs by at least 1.0 percentage point, preferably by at least 1.0 to 5.5 percentage points. Preferably, the mass content of molybdenum oxide differs by at least 0.8 percentage point, preferably by 0.8 to 4.5 percentage points, and the mass content of cobalt oxide differs by at least 0.1 percentage point, preferably by 0.2 to 1.0 percentage point. When the hydrodemetallization catalyst E is loaded in multiple beds, the total acid content of the catalyst between adjacent hydrodemetallization catalyst E beds should differ by at least 0.02 mmol / g, preferably 0.02 to 0.10 mmol / g.

9. The method according to any one of claims 1 to 3, characterized in that: The hydrodesulfurization catalyst F is one or more catalysts; when the hydrodesulfurization catalyst F is multiple catalysts, along the logistics direction, the active metal mass content of each catalyst gradually increases, and the total acid content of the catalyst gradually increases; When the hydrodesulfurization catalyst F is loaded in multiple beds, the mass content of the active metals calculated as oxides between two adjacent beds of the hydrodesulfurization catalyst F differs by at least 1.0 percentage point, preferably by at least 1.0 to 6.0 percentage points. Preferably, the mass content of molybdenum oxide differs by at least 0.8 percentage point, preferably by 0.8 to 5.0 percentage points, and the mass content of nickel oxide differs by at least 0.1 percentage point, preferably by 0.2 to 1.0 percentage point. When the hydrodesulfurization catalyst F is loaded in multiple beds, the total acid content of the catalyst between two adjacent beds of hydrodesulfurization catalyst F should differ by at least 0.02 mmol / g, preferably 0.04 to 0.10 mmol / g.

10. The method according to any one of claims 1 to 3, characterized in that: The hydrodesulfurization catalyst G is one or more catalysts; when the hydrodesulfurization catalyst G is multiple catalysts, along the logistics direction, the active metal mass content of each catalyst gradually increases, and the total acid content of the catalyst gradually increases; When the hydrodesulfurization catalyst G is loaded in multiple beds, the mass content of the active metals calculated as oxides between two adjacent beds of the hydrodesulfurization catalyst G differs by at least 1.3 percentage points, preferably by at least 1.3 to 6.0 percentage points. Preferably, the mass content of molybdenum oxide differs by at least 1.1 percentage points, preferably by at least 1.1 to 5.0 percentage points, and the mass content of nickel oxide differs by at least 0.1 percentage point, preferably by at least 0.2 to 1.0 percentage point. When the hydrodesulfurization catalyst G is loaded in multiple beds, the total acid content of the catalyst between adjacent beds of the hydrodesulfurization catalyst G should differ by at least 0.01 mmol / g, preferably 0.02 to 0.10 mmol / g.

11. The method according to any one of claims 1 to 3, characterized in that: The hydrodesulfurization catalyst H is one or more catalysts; when the hydrodesulfurization catalyst H is multiple catalysts, along the logistics direction, the active metal mass content of each catalyst gradually increases, and the total acid content of the catalyst gradually increases; When the hydrodesulfurization catalyst H is loaded in multiple beds, the mass content of the active metals in two adjacent hydrodesulfurization catalyst H beds, calculated as oxides, differs by at least 1.3 percentage points, preferably by at least 1.3 to 6.0 percentage points. Preferably, the mass content of molybdenum oxide differs by at least 1.1 percentage points, at least 1.1 to 5.0 percentage points, and the mass content of cobalt oxide differs by at least 0.1 percentage point, at least 0.2 to 1.0 percentage points. When the hydrodesulfurization catalyst H is loaded in multiple beds, the total acid content of the catalyst between two adjacent beds of the hydrodesulfurization catalyst H should differ by at least 0.02 mmol / g, preferably 0.04 to 0.10 mmol / g.

12. Use of the grading method according to any one of claims 1 to 11 in residual oil hydroprocessing.

13. The application according to claim 12, characterized in that: The residual oil feedstock and hydrogen are fed from the top of the first reactor, and after contacting and reacting with the catalyst in the first reactor, the resulting logistics enter the second reactor from the top of the second reactor, and after contacting and reacting with the catalyst in the second reactor, the resulting logistics enter the third reactor from the top of the third reactor, and after contacting and reacting with the catalyst in the third reactor, the resulting logistics enter the fourth reactor from the top of the fourth reactor, and after contacting and reacting with the catalyst in the fourth reactor, a low-sulfur marine fuel oil blending component is obtained.

14. The use according to claim 12 or 13, characterized in that: The reaction conditions of the hydrogenation are as follows: the reaction hydrogen partial pressure is 15.0-20.0 MPa; the liquid hourly volume space velocity is 0.15-0.25 h -1 ; The hydrogen-to-oil ratio at the reactor inlet is 400-1000 Nm 3 / m 3 ; The average temperature of the catalyst bed in each reactor is: 350-380°C for the first reactor, 360-395°C for the second reactor, 370-400°C for the third reactor, and 375-410°C for the fourth reactor; Among them, along the logistics direction, the average temperature of the catalyst bed in the downstream reactor is higher than the average temperature in the upstream reactor; More preferably, the average temperature difference between the catalyst beds of two adjacent reactors in the first reactor, the second reactor and the third reactor is 5-17°C; the average temperature difference between the catalyst beds of the third reactor and the fourth reactor is 3-12°C.

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