Grading method of hydrocracking catalyst

Abstract

The invention discloses a hydrocracking catalyst grading method, which comprises the following contents: N hydrocracking catalyst bed layers are arranged along a material flowing direction, N is an integer greater than 2, and N can be 2, 3, 4, 4, 6, 7, 8; the mass content of the Y-type molecular sieve in the hydrocracking catalyst filled in the Nth hydrocracking catalyst bed layer is lower than the mass content of the Y-type molecular sieve in the hydrocracking catalyst filled in the (N + 1) th hydrocracking catalyst bed layer; the unit cell constant of the Y-type molecular sieve in the hydrocracking catalyst filled in the (N + 1) th hydrocracking catalyst bed layer is higher than that of the Y-type molecular sieve in the hydrocracking catalyst filled in the Nth hydrocracking catalyst bed layer, and the mass content is based on the weight of the catalyst bed layer where the Y-type molecular sieve is located. The method can significantly improve the properties of the hydrocracked unconverted oil.

Description

Technical Field

[0001] The present invention relates to a grading method for a hydrocracking catalyst, in particular to a grading method for a hydrocracking catalyst for improving the properties of hydrocracking tail oil. Background Art

[0002] Oil resources occupy a crucial position in today's global energy system, remaining one of the world's most important energy sources and unlikely to be fully replaced by other resources in the short term. With the increasing exploitation of global oil resources, the trend toward heavier and inferior crude oil is becoming increasingly pronounced. This, combined with an increase in large-molecular, condensed-ring hydrocarbons in oil products and greater processing difficulties, presents new challenges to the oil refining sector.

[0003] Hydrocracking technology is the most effective means of reducing the weight and cleaning of heavy oils. It is also the most critical technology for achieving product quality upgrades and product structure adjustments. It is a technological hub connecting the integrated development of "oil, chemical, and fiber," and chemical hydrocracking catalysts occupy a key position. Hydrocracking is an ideal process for chemical hydrocracking, where large molecular weight condensed-ring cyclic hydrocarbons in distillate oils are hydrogenated into light components as reforming feedstocks, while retaining paraffins in the heavy components as feedstocks for ethylene cracking. The hydrogenation process is exothermic, and feedstocks high in condensed-ring cyclic hydrocarbons have a high degree of unsaturation. The hydrogenation process releases a large amount of reaction heat, which brings many inconveniences to the operation of industrial units. Therefore, it is often necessary to inject cold hydrogen between the beds to control the bed temperature.

[0004] CN114686257 discloses a catalyst grading method for a two-stage hydrocracking process. The method involves passing vacuum gas oil and hydrogen into a hydrorefining reaction zone. The refined effluent enters a first-stage hydrocracking reaction zone, where it sequentially contacts and reacts with two or more catalyst beds. The first-stage cracking products are separated to produce a tail oil fraction, which is then passed into a second-stage cracking reaction zone for deep cracking.

[0005] CN105018137 discloses a low-energy, high-yield hydrocracking method for high-quality jet fuel. This method involves mixing feedstock oil with hydrogen, then passing it through hydrorefining and a first cracking reaction zone. The resulting intermediate distillate is then separated and cracked in a second cracking reaction zone. The first cracking reaction zone is loaded with at least two catalysts, A and B. Catalyst A contains 15-50% modified Y molecular sieve, while catalyst B contains 3-30% modified Y molecular sieve. The Y molecular sieve content in catalyst A is 10-25% higher than that in catalyst B.

[0006] CN114686256 discloses a grading method for a hydrocracking catalyst, wherein the feedstock oil and hydrogen pass through a refining reactor together and then directly enter a hydrocracking reactor, where they react with two or more hydrocracking catalyst beds in sequence. The NiO mass fraction of the lower catalyst layer decreases, the CoO mass fraction increases, the MoO3 mass fraction decreases, the mass fraction of the total active metal oxides decreases, and the molecular sieve content decreases.

[0007] The prior art generally does not consider the problem of the properties of hydrocracked unconverted oil, and the properties of hydrocracked unconverted oil need to be further improved. Summary of the Invention

[0008] In view of the deficiencies in the prior art, the present invention discloses a grading method for a hydrocracking catalyst, which can significantly improve the properties of hydrocracking unconverted oil.

[0009] Through in-depth research, the inventors found that the existing technology usually adopts a method of reducing the cracking activity of the hydrocracking catalyst for grading. However, as the reaction progresses, the content of polycyclic aromatic hydrocarbons in the cracking products becomes less and less, and at the same time, the cracking activity of the hydrocracking catalyst becomes lower and lower. These two factors make the conversion ability of polycyclic aromatic hydrocarbons worse in the later stage of the hydrocracking reaction, resulting in poor properties of the unconverted oil.

[0010] A grading method for a hydrocracking catalyst comprises the following steps: providing N hydrocracking catalyst beds along a material flow direction, wherein N is an integer greater than 2 and may be 2, 3, 4, 4, 6, 7, or 8; the mass content of the Y-type molecular sieve in the hydrocracking catalyst loaded in the Nth hydrocracking catalyst bed is lower than the mass content of the Y-type molecular sieve in the hydrocracking catalyst loaded in the N+1th hydrocracking catalyst bed; the unit cell constant of the Y-type molecular sieve in the hydrocracking catalyst loaded in the N+1th hydrocracking catalyst bed is higher than the unit cell constant of the Y-type molecular sieve in the hydrocracking catalyst loaded in the Nth hydrocracking catalyst bed; and the mass content is based on the weight of the catalyst bed in which the Y-type molecular sieve is loaded.

[0011] In the above method, the mass content of Y-type molecular sieve in the hydrocracking catalyst loaded in the Nth hydrocracking catalyst bed differs from the mass content of Y-type molecular sieve in the hydrocracking catalyst loaded in the N+1th hydrocracking catalyst bed by 10-40%, preferably by 15-35%, and more preferably by 20-30%.

[0012] In the above method, the unit cell constant of the Y-type molecular sieve in the hydrocracking catalyst loaded in the N+1th hydrocracking catalyst bed is 0.001 to 0.012 nm different from the unit cell constant of the Y-type molecular sieve in the hydrocracking catalyst loaded in the Nth hydrocracking catalyst bed, preferably 0.004 to 0.010 nm, and more preferably 0.006 to 0.008 nm lower.

[0013] In the above method, the active metal component in the hydrocracking catalyst is a Group VIB metal and / or a Group VIII metal, preferably tungsten (W) and molybdenum (Mo) among the Group VIB metals, and preferably cobalt (Co) and nickel (Ni) among the Group VIII metals; based on the weight of the hydrocracking catalyst, the Group VIB metal (calculated as oxide) is 8% to 25%; and the Group VIII metal (calculated as oxide) is 1% to 7%.

[0014] In the above method, the hydrocracking catalyst bed can be arranged in one hydrocracking reactor or in multiple hydrocracking reactors connected in series.

[0015] In the above method, the raw oil and hydrogen pass through a refined catalyst and enter the bed of a hydrocracking reactor. The reaction effluent passes through a high-pressure separator and a low-pressure separator to separate gas and liquid components. The obtained liquid component is transported to a distillation tower for component separation at different distillation ranges to obtain light naphtha, heavy naphtha and hydrocracking unconverted oil.

[0016] In the above method, the properties of the raw oil are as follows: the density of the raw oil at 20°C is 0.8980 to 0.9180 g·cm -3 The initial distillation point is 290-340°C, the final distillation point is 500-550°C, and the sulfur content is 14,000-20,000 μg·g -1 , nitrogen content is 600~1000μg·g -1 ;

[0017] In the above method, in the mass spectrum composition of the raw oil, the mass proportion of chain alkanes is 18-23%, the mass proportion of total cycloalkanes is 32-37%, and the mass proportion of total aromatics is 41-45%.

[0018] In the above method, the hydrorefining catalyst is composed of a carrier and a metal. The hydrorefining catalyst used is a commercially available industrial hydrorefining catalyst, preferably FF-46, FF-56 and FF-66 hydrorefining catalysts from Fushun Petrochemical Research Institute.

[0019] In the above method, the hydrofining reaction conditions are as follows: reaction pressure 10-18 MPa, hydrogen feedstock oil volume ratio 800:1-1500:1. The internal temperature of the refining reactor bed is 320-420°C, and the volume space velocity is 0.8-2.0h-1 .

[0020] In the above method, the hydrocracking reaction conditions are as follows: reaction pressure 10-18 MPa, hydrogen feedstock oil volume ratio 800:1-1500:1, cracking reactor bed internal temperature 340-400 ° C, volume space velocity 1.0-2.0 h -1 .

[0021] In the above method, the hydrocracking catalyst can be a commercially available product or prepared according to existing technology. The hydrocracking catalyst can be prepared by a kneading method or an impregnation method. The kneading method is to mix Y molecular sieves, alumina, active metal oxides and / or active metal salts of different unit cell constants evenly, add dilute nitric acid solution and distilled water, and obtain a shaped catalyst after kneading and extrusion. The shaped catalyst is dried and calcined to obtain the final hydrocracking catalyst; the impregnation method is to shape Y molecular sieves and alumina of different unit cell constants, load active metals, and obtain the final hydrocracking catalyst after drying and calcining.

[0022] Compared with the prior art, the grading method of a hydrocracking catalyst of the present invention has the following advantages: the unit cell constant of the Y-type molecular sieve contained in the hydrocracking catalyst loaded in different hydrocracking catalyst beds along the direction of material flow increases successively, and the adsorption capacity for condensed aromatic hydrocarbon macromolecules increases successively, thereby reducing the hydrocracking activity. As the content of the Y-type molecular sieve decreases successively, the content of condensed aromatic hydrocarbon macromolecules gradually decreases as the reaction depth of condensed aromatic hydrocarbons increases, and its reaction efficiency gradually decreases, resulting in the problem of poor quality of unconverted oil after hydrocracking. Although the content of condensed aromatic hydrocarbon macromolecules gradually decreases in the method of the present invention, the adsorption capacity of the hydrocracking catalyst gradually increases, ensuring that under conditions of low condensed aromatic hydrocarbon macromolecule content, it can also be efficiently and preferentially converted, thereby greatly improving the properties of the product, especially the properties of the unconverted oil. At the same time, the method of the present invention well matches the characteristics of the exothermic reaction in the hydrocracking process, reduces the cold hydrogen consumption of the industrial device, and has significant economic benefits. DETAILED DESCRIPTION

[0023] The hydrocracking grading method of the present invention is described in detail below with reference to the following examples and comparative examples. However, the following examples do not limit the present invention. Unless otherwise specified, % in the context of the present invention refers to mass percentage.

[0024] The examples and comparative examples of the present invention may use the following four different hydrocracking catalysts, which are respectively denoted as hydrocracking catalyst A, hydrocracking catalyst B, hydrocracking catalyst C, and hydrocracking catalyst D.

[0025] The active metal components in the hydrocracking catalyst A are Group VIB metals and Group VIII metals, preferably tungsten (W) and molybdenum (Mo) as Group VIB metals, and preferably cobalt (Co) and nickel (Ni) as Group VIII metals; based on the weight percentage of the catalyst after calcination at 500°C for 4 hours, the aluminum oxide content is 5% to 35%; the Group VIB metal (calculated as oxide) is 8% to 25%; the Group VIII metal (calculated as oxide) is 1% to 7%; the Y-type molecular sieve content is between 40% and 70%; the unit cell constant of the Y-type molecular sieve is between 2.425 and 2.435 nm; and the relative crystallinity is between 85% and 105%.

[0026] The active metal components in the hydrocracking catalyst B are Group VIB metals and Group VIII metals, preferably tungsten (W) and molybdenum (Mo) as Group VIB metals, and preferably cobalt (Co) and nickel (Ni) as Group VIII metals; based on the weight percentage of the catalyst after calcination at 500°C for 4 hours, the content of alumina is 15% to 45%; the content of the Group VIB metal (calculated as oxide) is 8% to 25%; the content of the Group VIII metal (calculated as oxide) is 1% to 7%; the content of the Y-type molecular sieve is between 30% and 55%; the unit cell constant of the Y-type molecular sieve is between 2.430 and 2.438 nm; and the relative crystallinity is between 85% and 105%.

[0027] The active metal components in the hydrocracking catalyst C are Group VIB metals and Group VIII metals, preferably tungsten (W) and molybdenum (Mo) as Group VIB metals, and preferably cobalt (Co) and nickel (Ni) as Group VIII metals. The catalyst weight percentage after calcination at 500° C. for 4 hours is as follows: alumina is 30% to 50%; the Group VIB metal (calculated as oxide) is 8% to 25%; the Group VIII metal (calculated as oxide) is 1% to 7%; the Y-type molecular sieve content is between 20% and 45%, preferably 25% to 40%; the unit cell constant of the Y-type molecular sieve is between 2.435 and 2.440 nm, and the relative crystallinity is between 85% and 105%.

[0028] The active metal components in the hydrocracking catalyst D are Group VIB metals and Group VIII metals, preferably tungsten (W) and molybdenum (Mo) as Group VIB metals, and preferably cobalt (Co) and nickel (Ni) as Group VIII metals; based on the weight percentage of the catalyst after calcination at 500°C for 4 hours, the aluminum oxide content is 45% to 75%; the Group VIB metal (calculated as oxide) is 8% to 25%; the Group VIII metal (calculated as oxide) is 1% to 7%; the Y-type molecular sieve content is between 5% and 25%, preferably 9% to 21%; the unit cell constant of the Y-type molecular sieve is between 2.436 and 2.446 nm; and the relative crystallinity is between 85 and 105%.

[0029] The Y-type molecular sieve content in hydrocracking catalyst A is 10-40% higher, preferably 15-35% higher, than the Y-type molecular sieve content in hydrocracking catalyst B. The Y-type molecular sieve content in hydrocracking catalyst B is 10-35% higher, preferably 15-30% higher, than the Y-type molecular sieve content in hydrocracking catalyst C. The Y-type molecular sieve content in hydrocracking catalyst C is 15-35% higher, preferably 20-30% higher, than the Y-type molecular sieve content in hydrocracking catalyst D.

[0030] The Y-type molecular sieve unit cell constant in hydrocracking catalyst A is 0.005-0.012 nm lower than the Y-type molecular sieve unit cell constant in hydrocracking catalyst B, preferably 0.008-0.010 nm lower. The Y-type molecular sieve unit cell constant in hydrocracking catalyst B is 0.004-0.010 nm lower than the Y-type molecular sieve unit cell constant in hydrocracking catalyst C, preferably 0.006-0.008 nm lower. The Y-type molecular sieve unit cell constant in hydrocracking catalyst C is 0.001-0.009 nm lower than the Y-type molecular sieve unit cell constant in hydrocracking catalyst D, preferably 0.004-0.007 nm lower.

[0031] In the method of the present invention, the raw oil and hydrogen are passed through a refining catalyst and then sequentially passed through several different hydrocracking catalysts for reaction. The reaction effluent is separated into gas and liquid components after passing through a high-pressure separator and a low-pressure separator. The obtained liquid components are transported to a fractionating tower for component separation at different distillation ranges to obtain light naphtha, heavy naphtha and tower bottom oil, wherein the tower bottom oil is the hydrocracking unconverted oil.

[0032] The hydrocracking catalyst of the present invention can be loaded with two hydrocracking catalysts (hydrocracking catalyst A, hydrocracking catalyst B); it can also be loaded with three hydrocracking catalysts (hydrocracking catalyst A, hydrocracking catalyst B, hydrocracking catalyst C); it can also be loaded with four hydrocracking catalysts (hydrocracking catalyst A, hydrocracking catalyst B, hydrocracking catalyst C, hydrocracking catalyst D), preferably four hydrocracking catalysts are loaded.

[0033] In the present invention, the relative crystallinity of the Y molecular sieve is determined by X-ray diffraction, which is determined according to the Chinese petrochemical industry standard SH / T 0340-92. The unit cell constant of the Y molecular sieve is determined by X-ray diffraction, which is determined according to the Chinese petrochemical industry standard SH / T 0339-92.

[0034] The properties of the vacuum gas oil (VGO) used in the experiment are shown in Table 1. A series, single-pass process flow was used to evaluate the catalyst's reactivity. Process conditions included a reaction pressure of 10-18 MPa, a hydrogen-to-oil volume ratio of 800:1 to 1500:1, a refining reactor bed temperature of 320-420°C, and a volume space velocity of 0.8-2.0 h / min.-1 The internal temperature of the cracking reactor bed is 340-400℃, and the volume space velocity is 1.0-2.0h -1 The catalyst performance evaluation results are shown in Table 2.

[0035] Example 1

[0036] A Y molecular sieve having a unit cell constant of 2.425 nm and a relative crystallinity of 85%, aluminum oxide, molybdenum trioxide, and nickel nitrate were uniformly mixed. The weight fractions of the components in the final catalyst after uniform mixing were as follows: Y molecular sieve (40 wt%), aluminum oxide (35 wt%), molybdenum trioxide (18 wt%), and nickel oxide (7 wt%). A dilute nitric acid solution and distilled water were then added, and the mixture was kneaded and extruded to obtain a shaped catalyst. The shaped catalyst was then dried and calcined to obtain the final hydrocracking catalyst A.

[0037] A Y molecular sieve having a unit cell constant of 2.430 nm and a relative crystallinity of 92%, aluminum oxide, molybdenum trioxide, and nickel nitrate were uniformly mixed. The weight fractions of the components in the final catalyst after uniform mixing were as follows: Y molecular sieve (30 wt%), aluminum oxide (45 wt%), molybdenum trioxide (20 wt%), and nickel oxide (5 wt%). A dilute nitric acid solution and distilled water were then added, and the mixture was kneaded and extruded to obtain a shaped catalyst. The shaped catalyst was then dried and calcined to obtain the final hydrocracking catalyst B.

[0038] A Y molecular sieve having a unit cell constant of 2.435 nm and a relative crystallinity of 96% is uniformly mixed with aluminum oxide, molybdenum trioxide, and nickel nitrate. The weight fractions of the components in the final catalyst are as follows: Y molecular sieve (20 wt%), aluminum oxide (50 wt%), molybdenum trioxide (25 wt%), and nickel oxide (5 wt%). A dilute nitric acid solution and distilled water are then added, and the mixture is kneaded and extruded to obtain a shaped catalyst. The shaped catalyst is then dried and calcined to obtain the final hydrocracking catalyst C.

[0039] A Y molecular sieve having a unit cell constant of 2.436 nm and a relative crystallinity of 100%, aluminum oxide, molybdenum trioxide, and nickel nitrate were uniformly mixed. The weight fractions of the components in the final catalyst were as follows: Y molecular sieve (5 wt%), aluminum oxide (75 wt%), molybdenum trioxide (18 wt%), and nickel oxide (2 wt%). A dilute nitric acid solution and distilled water were then added, and the mixture was kneaded and extruded to obtain a shaped catalyst. The shaped catalyst was then dried and calcined to obtain the final hydrocracking catalyst D.

[0040] The four hydrocracking catalysts were loaded into the reactor from top to bottom. The crude oil first passed through the refining catalyst, and then passed through hydrocracking catalyst A, hydrocracking catalyst B, hydrocracking catalyst C, and hydrocracking catalyst D in sequence for reaction. The reaction pressure was controlled at 15.7 MPa, the hydrogen-oil volume ratio was 1200:1, the bed temperature of the refining reactor was 385°C, and the space velocity of the hydrorefining catalyst was 1.0 h -1 The volume space velocity of hydrocracking catalysts A, B, C and D is 1.5h -1 The contact temperature between the reaction materials and the top layer of hydrocracking catalyst A was controlled at 375°C. The reaction effluent passed through a high-pressure separator and a low-pressure separator to separate gas and liquid components. The resulting liquid components were transported to a fractionating tower for separation according to different distillation ranges, yielding light naphtha, heavy naphtha, and tower bottoms.

[0041] Example 2

[0042] A Y molecular sieve having a unit cell constant of 2.425 nm and a relative crystallinity of 98%, aluminum oxide, molybdenum trioxide, and nickel nitrate were uniformly mixed. The weight fractions of the components in the final catalyst after uniform mixing were as follows: Y molecular sieve (70 wt%), aluminum oxide (10 wt%), molybdenum trioxide (18 wt%), and nickel oxide (2 wt%). A dilute nitric acid solution and distilled water were then added, and the mixture was kneaded and extruded to obtain a shaped catalyst. The shaped catalyst was then dried and calcined to obtain the final hydrocracking catalyst A.

[0043] A Y molecular sieve having a unit cell constant of 2.436 nm and a relative crystallinity of 94%, aluminum oxide, molybdenum trioxide, and nickel nitrate were uniformly mixed. The weight fractions of the components in the final catalyst after uniform mixing were as follows: Y molecular sieve (30 wt%), aluminum oxide (40 wt%), molybdenum trioxide (25 wt%), and nickel oxide (5 wt%). A dilute nitric acid solution and distilled water were then added, and the mixture was kneaded and extruded to obtain a shaped catalyst. The shaped catalyst was then dried and calcined to obtain the final hydrocracking catalyst B.

[0044] A Y molecular sieve having a unit cell constant of 2.440 nm and a relative crystallinity of 88%, aluminum oxide, molybdenum trioxide, and nickel nitrate are uniformly mixed. The weight fractions of the components in the final catalyst after uniform mixing are as follows: Y molecular sieve (20 wt%), aluminum oxide (50 wt%), molybdenum trioxide (23 wt%), and nickel oxide (7 wt%). Dilute nitric acid solution and distilled water are then added, and the mixture is kneaded and extruded to obtain a shaped catalyst. The shaped catalyst is then dried and calcined to obtain the final hydrocracking catalyst C.

[0045] A Y molecular sieve having a unit cell constant of 2.443 nm and a relative crystallinity of 103%, aluminum oxide, molybdenum trioxide, and nickel nitrate were uniformly mixed. The weight fractions of the components in the final catalyst were as follows: Y molecular sieve (5 wt%), aluminum oxide (75 wt%), molybdenum trioxide (19 wt%), and nickel oxide (1 wt%). A dilute nitric acid solution and distilled water were then added, and the mixture was kneaded and extruded to obtain a shaped catalyst. The shaped catalyst was then dried and calcined to obtain the final hydrocracking catalyst D.

[0046] The four hydrocracking catalysts were loaded into the reactor from top to bottom. The crude oil first passed through the refining catalyst, and then passed through hydrocracking catalyst A, hydrocracking catalyst B, hydrocracking catalyst C, and hydrocracking catalyst D in sequence for reaction. The reaction pressure was controlled at 15.7 MPa, the hydrogen-oil volume ratio was 1200:1, the bed temperature of the refining reactor was 385°C, and the space velocity of the hydrorefining catalyst was 1.0 h -1 The volume space velocity of hydrocracking catalysts A, B, C and D is 1.5h -1 The contact temperature between the reaction materials and the top layer of hydrocracking catalyst A was controlled at 375°C. The reaction effluent passed through a high-pressure separator and a low-pressure separator to separate gas and liquid components. The resulting liquid components were transported to a fractionating tower for separation according to different distillation ranges, yielding light naphtha, heavy naphtha, and tower bottoms.

[0047] Example 3

[0048] A Y molecular sieve having a unit cell constant of 2.425 nm and a relative crystallinity of 98%, aluminum oxide, molybdenum trioxide, and nickel nitrate were uniformly mixed. The weight fractions of the components in the final catalyst after uniform mixing were as follows: Y molecular sieve (70 wt%), aluminum oxide (10 wt%), molybdenum trioxide (18 wt%), and nickel oxide (2 wt%). A dilute nitric acid solution and distilled water were then added, and the mixture was kneaded and extruded to obtain a shaped catalyst. The shaped catalyst was then dried and calcined to obtain the final hydrocracking catalyst A.

[0049] A Y molecular sieve having a unit cell constant of 2.436 nm and a relative crystallinity of 94%, aluminum oxide, molybdenum trioxide, and nickel nitrate were uniformly mixed. The weight fractions of the components in the final catalyst after uniform mixing were as follows: Y molecular sieve (40 wt%), aluminum oxide (30 wt%), molybdenum trioxide (25 wt%), and nickel oxide (5 wt%). A dilute nitric acid solution and distilled water were then added, and the mixture was kneaded and extruded to obtain a shaped catalyst. The shaped catalyst was then dried and calcined to obtain the final hydrocracking catalyst B.

[0050] A Y molecular sieve having a unit cell constant of 2.440 nm and a relative crystallinity of 88%, aluminum oxide, molybdenum trioxide, and nickel nitrate are uniformly mixed. The weight fractions of the components in the final catalyst after uniform mixing are as follows: Y molecular sieve (20 wt%), aluminum oxide (50 wt%), molybdenum trioxide (23 wt%), and nickel oxide (7 wt%). Dilute nitric acid solution and distilled water are then added, and the mixture is kneaded and extruded to obtain a shaped catalyst. The shaped catalyst is then dried and calcined to obtain the final hydrocracking catalyst C.

[0051] A Y molecular sieve having a unit cell constant of 2.443 nm and a relative crystallinity of 103%, aluminum oxide, molybdenum trioxide, and nickel nitrate were uniformly mixed. The weight fractions of the components in the final catalyst were as follows: Y molecular sieve (5 wt%), aluminum oxide (75 wt%), molybdenum trioxide (19 wt%), and nickel oxide (1 wt%). A dilute nitric acid solution and distilled water were then added, and the mixture was kneaded and extruded to obtain a shaped catalyst. The shaped catalyst was then dried and calcined to obtain the final hydrocracking catalyst D.

[0052] The four hydrocracking catalysts were loaded into the reactor from top to bottom. The crude oil first passed through the refining catalyst, and then passed through hydrocracking catalyst A, hydrocracking catalyst B, hydrocracking catalyst C, and hydrocracking catalyst D in sequence for reaction. The reaction pressure was controlled at 15.7 MPa, the hydrogen-oil volume ratio was 1200:1, the bed temperature of the refining reactor was 385°C, and the space velocity of the hydrorefining catalyst was 1.0 h -1 The volume space velocity of hydrocracking catalysts A, B, C and D is 1.5h -1 The contact temperature between the reaction materials and the top layer of hydrocracking catalyst A was controlled at 375°C. The reaction effluent passed through a high-pressure separator and a low-pressure separator to separate gas and liquid components. The resulting liquid components were transported to a fractionating tower for separation according to different distillation ranges, yielding light naphtha, heavy naphtha, and tower bottoms.

[0053] Example 4

[0054] A Y molecular sieve having a unit cell constant of 2.425 nm and a relative crystallinity of 98%, aluminum oxide, molybdenum trioxide, and nickel nitrate were uniformly mixed. The weight fractions of the components in the final catalyst after uniform mixing were as follows: Y molecular sieve (70 wt%), aluminum oxide (10 wt%), molybdenum trioxide (18 wt%), and nickel oxide (2 wt%). A dilute nitric acid solution and distilled water were then added, and the mixture was kneaded and extruded to obtain a shaped catalyst. The shaped catalyst was then dried and calcined to obtain the final hydrocracking catalyst A.

[0055] A Y molecular sieve having a unit cell constant of 2.434 nm and a relative crystallinity of 94%, aluminum oxide, molybdenum trioxide, and nickel nitrate were uniformly mixed. The weight fractions of the components in the final catalyst after uniform mixing were as follows: Y molecular sieve (30 wt%), aluminum oxide (40 wt%), molybdenum trioxide (25 wt%), and nickel oxide (5 wt%). A dilute nitric acid solution and distilled water were then added, and the mixture was kneaded and extruded to obtain a shaped catalyst. The shaped catalyst was then dried and calcined to obtain the final hydrocracking catalyst B.

[0056] A Y molecular sieve having a unit cell constant of 2.440 nm and a relative crystallinity of 88%, aluminum oxide, molybdenum trioxide, and nickel nitrate are uniformly mixed. The weight fractions of the components in the final catalyst after uniform mixing are as follows: Y molecular sieve (20 wt%), aluminum oxide (50 wt%), molybdenum trioxide (23 wt%), and nickel oxide (7 wt%). Dilute nitric acid solution and distilled water are then added, and the mixture is kneaded and extruded to obtain a shaped catalyst. The shaped catalyst is then dried and calcined to obtain the final hydrocracking catalyst C.

[0057] A Y molecular sieve having a unit cell constant of 2.443 nm and a relative crystallinity of 103%, aluminum oxide, molybdenum trioxide, and nickel nitrate were uniformly mixed. The weight fractions of the components in the final catalyst were as follows: Y molecular sieve (5 wt%), aluminum oxide (75 wt%), molybdenum trioxide (19 wt%), and nickel oxide (1 wt%). A dilute nitric acid solution and distilled water were then added, and the mixture was kneaded and extruded to obtain a shaped catalyst. The shaped catalyst was then dried and calcined to obtain the final hydrocracking catalyst D.

[0058] The four hydrocracking catalysts were loaded into the reactor from top to bottom. The crude oil first passed through the refining catalyst, and then passed through hydrocracking catalyst A, hydrocracking catalyst B, hydrocracking catalyst C, and hydrocracking catalyst D in sequence for reaction. The reaction pressure was controlled at 15.7 MPa, the hydrogen-oil volume ratio was 1200:1, the bed temperature of the refining reactor was 385°C, and the space velocity of the hydrorefining catalyst was 1.0 h -1 The volume space velocity of hydrocracking catalysts A, B, C and D is 1.5h -1 The contact temperature between the reaction materials and the top layer of hydrocracking catalyst A was controlled at 375°C. The reaction effluent passed through a high-pressure separator and a low-pressure separator to separate gas and liquid components. The resulting liquid components were transported to a fractionating tower for separation according to different distillation ranges, yielding light naphtha, heavy naphtha, and tower bottoms.

[0059] Example 5

[0060] A Y molecular sieve having a unit cell constant of 2.425 nm and a relative crystallinity of 98%, aluminum oxide, molybdenum trioxide, and nickel nitrate were uniformly mixed. The weight fractions of the components in the final catalyst after uniform mixing were as follows: Y molecular sieve (70 wt%), aluminum oxide (10 wt%), molybdenum trioxide (18 wt%), and nickel oxide (2 wt%). A dilute nitric acid solution and distilled water were then added, and the mixture was kneaded and extruded to obtain a shaped catalyst. The shaped catalyst was then dried and calcined to obtain the final hydrocracking catalyst A.

[0061] A Y molecular sieve having a unit cell constant of 2.436 nm and a relative crystallinity of 94%, aluminum oxide, molybdenum trioxide, and nickel nitrate were uniformly mixed. The weight fractions of the components in the final catalyst after uniform mixing were as follows: Y molecular sieve (30 wt%), aluminum oxide (40 wt%), molybdenum trioxide (25 wt%), and nickel oxide (5 wt%). A dilute nitric acid solution and distilled water were then added, and the mixture was kneaded and extruded to obtain a shaped catalyst. The shaped catalyst was then dried and calcined to obtain the final hydrocracking catalyst B.

[0062] The two hydrocracking catalysts were loaded into the reactor from top to bottom. The crude oil first passed through the refining catalyst, then passed through the hydrocracking catalyst A and then the hydrocracking catalyst B. The reaction pressure was controlled at 15.7 MPa, the hydrogen-oil volume ratio was 1200:1, the bed temperature of the refining reactor was 385°C, and the space velocity of the hydrorefining catalyst was 1.0 h -1 The volume space velocity of hydrocracking catalysts A and B is 1.5h -1 The contact temperature between the reaction materials and the top layer of hydrocracking catalyst A was controlled at 375°C. The reaction effluent passed through a high-pressure separator and a low-pressure separator to separate gas and liquid components. The resulting liquid components were transported to a fractionating tower for separation according to different distillation ranges, yielding light naphtha, heavy naphtha, and tower bottoms.

[0063] Example 6

[0064] A Y molecular sieve having a unit cell constant of 2.425 nm and a relative crystallinity of 98%, aluminum oxide, molybdenum trioxide, and nickel nitrate were uniformly mixed. The weight fractions of the components in the final catalyst after uniform mixing were as follows: Y molecular sieve (70 wt%), aluminum oxide (10 wt%), molybdenum trioxide (18 wt%), and nickel oxide (2 wt%). A dilute nitric acid solution and distilled water were then added, and the mixture was kneaded and extruded to obtain a shaped catalyst. The shaped catalyst was then dried and calcined to obtain the final hydrocracking catalyst A.

[0065] A Y molecular sieve having a unit cell constant of 2.436 nm and a relative crystallinity of 94%, aluminum oxide, molybdenum trioxide, and nickel nitrate were uniformly mixed. The weight fractions of the components in the final catalyst after uniform mixing were as follows: Y molecular sieve (30 wt%), aluminum oxide (40 wt%), molybdenum trioxide (25 wt%), and nickel oxide (5 wt%). A dilute nitric acid solution and distilled water were then added, and the mixture was kneaded and extruded to obtain a shaped catalyst. The shaped catalyst was then dried and calcined to obtain the final hydrocracking catalyst B.

[0066] A Y molecular sieve having a unit cell constant of 2.440 nm and a relative crystallinity of 88%, aluminum oxide, molybdenum trioxide, and nickel nitrate are uniformly mixed. The weight fractions of the components in the final catalyst after uniform mixing are as follows: Y molecular sieve (20 wt%), aluminum oxide (50 wt%), molybdenum trioxide (23 wt%), and nickel oxide (7 wt%). Dilute nitric acid solution and distilled water are then added, and the mixture is kneaded and extruded to obtain a shaped catalyst. The shaped catalyst is then dried and calcined to obtain the final hydrocracking catalyst C.

[0067] The three hydrocracking catalysts were loaded into the reactor from top to bottom. The crude oil first passed through the refining catalyst, then passed through hydrocracking catalyst A, hydrocracking catalyst B, and hydrocracking catalyst C in sequence to react. The reaction pressure was controlled at 15.7 MPa, the hydrogen-oil volume ratio was 1200:1, the bed temperature of the refining reactor was 385°C, and the space velocity of the hydrorefining catalyst was 1.0 h -1 The volume space velocity of hydrocracking catalysts A, B and C is 1.5h -1 The contact temperature between the reaction materials and the top layer of hydrocracking catalyst A was controlled at 375°C. The reaction effluent passed through a high-pressure separator and a low-pressure separator to separate gas and liquid components. The resulting liquid components were transported to a fractionating tower for separation according to different distillation ranges, yielding light naphtha, heavy naphtha, and tower bottoms.

[0068] Comparative Example 1

[0069] A Y molecular sieve having a unit cell constant of 2.425 nm and a relative crystallinity of 94%, aluminum oxide, molybdenum trioxide, and nickel nitrate were uniformly mixed. The weight fractions of the components in the final catalyst after uniform mixing were as follows: Y molecular sieve (70 wt%), aluminum oxide (10 wt%), molybdenum trioxide (18 wt%), and nickel oxide (2 wt%). A dilute nitric acid solution and distilled water were then added, and the mixture was kneaded and extruded to obtain a shaped catalyst. The shaped catalyst was then dried and calcined to obtain the final hydrocracking catalyst A.

[0070] A Y molecular sieve having a unit cell constant of 2.425 nm and a relative crystallinity of 94%, aluminum oxide, molybdenum trioxide, and nickel nitrate were uniformly mixed. The weight fractions of the components in the final catalyst after uniform mixing were as follows: Y molecular sieve (30 wt%), aluminum oxide (40 wt%), molybdenum trioxide (25 wt%), and nickel oxide (5 wt%). A dilute nitric acid solution and distilled water were then added, and the mixture was kneaded and extruded to obtain a shaped catalyst. The shaped catalyst was then dried and calcined to obtain the final hydrocracking catalyst B.

[0071] The two hydrocracking catalysts were loaded into the reactor from top to bottom. The crude oil first passed through the refining catalyst, then passed through the hydrocracking catalyst A and then the hydrocracking catalyst B. The reaction pressure was controlled at 15.7 MPa, the hydrogen-oil volume ratio was 1200:1, the bed temperature of the refining reactor was 385°C, and the space velocity of the hydrorefining catalyst was 1.0 h -1 The volume space velocity of hydrocracking catalysts A and B is 1.5h -1 The contact temperature between the reaction materials and the top layer of hydrocracking catalyst A was controlled at 375°C. The reaction effluent passed through a high-pressure separator and a low-pressure separator to separate gas and liquid components. The resulting liquid components were transported to a fractionating tower for separation according to different distillation ranges, yielding light naphtha, heavy naphtha, and tower bottoms.

[0072] Comparative Example 2

[0073] A Y molecular sieve having a unit cell constant of 2.425 nm and a relative crystallinity of 98%, aluminum oxide, molybdenum trioxide, and nickel nitrate were uniformly mixed. The weight fractions of the components in the final catalyst after uniform mixing were as follows: Y molecular sieve (70 wt%), aluminum oxide (10 wt%), molybdenum trioxide (18 wt%), and nickel oxide (2 wt%). A dilute nitric acid solution and distilled water were then added, and the mixture was kneaded and extruded to obtain a shaped catalyst. The shaped catalyst was then dried and calcined to obtain the final hydrocracking catalyst A.

[0074] A Y molecular sieve having a unit cell constant of 2.436 nm and a relative crystallinity of 94%, aluminum oxide, molybdenum trioxide, and nickel nitrate were uniformly mixed. The weight fractions of the components in the final catalyst after uniform mixing were as follows: Y molecular sieve (70 wt%), aluminum oxide (10 wt%), molybdenum trioxide (18 wt%), and nickel oxide (2 wt%). A dilute nitric acid solution and distilled water were then added, and the mixture was kneaded and extruded to obtain a shaped catalyst. The shaped catalyst was then dried and calcined to obtain the final hydrocracking catalyst B.

[0075] The two hydrocracking catalysts were loaded into the reactor from top to bottom. The crude oil first passed through the refining catalyst, then passed through the hydrocracking catalyst A and then the hydrocracking catalyst B. The reaction pressure was controlled at 15.7 MPa, the hydrogen-oil volume ratio was 1200:1, the bed temperature of the refining reactor was 385°C, and the space velocity of the hydrorefining catalyst was 1.0 h -1 The volume space velocity of hydrocracking catalysts A and B is 1.5h -1 The contact temperature between the reaction materials and the top layer of hydrocracking catalyst A was controlled at 375°C. The reaction effluent passed through a high-pressure separator and a low-pressure separator to separate gas and liquid components. The resulting liquid components were transported to a fractionating tower for separation according to different distillation ranges, yielding light naphtha, heavy naphtha, and tower bottoms.

[0076] Table 1 Properties of crude oil

[0077]

[0078]

[0079] Table 2 Catalyst performance evaluation results

[0080] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 >320℃ unconverted oil yield, % 36.6 34.5 34.0 34.7 37.0 36.2 39.7 36.5 BMCI value 11.5 10.4 9.6 9.4 12.0 11.1 13.0 14.7 Paraffin content, % 42.3 45.0 47.6 48.0 40.4 42.3 38.5 36.0 Aromatic content, % 2.5 2.4 1.8 1.6 2.7 2.6 3.0 6.3

Claims

1. A grading method for a hydrocracking catalyst, characterized in that: The method comprises the following contents: N hydrocracking catalyst beds are arranged along the material flow direction, wherein N is an integer greater than 2, and N can be 2, 3, 4, 4, 6, 7, or 8; the mass content of the Y-type molecular sieve in the hydrocracking catalyst loaded in the Nth hydrocracking catalyst bed is lower than the mass content of the Y-type molecular sieve in the hydrocracking catalyst loaded in the N+1th hydrocracking catalyst bed; the unit cell constant of the Y-type molecular sieve in the hydrocracking catalyst loaded in the N+1th hydrocracking catalyst bed is higher than the unit cell constant of the Y-type molecular sieve in the hydrocracking catalyst loaded in the Nth hydrocracking catalyst bed; and the mass content is based on the weight of the catalyst bed in which the Y-type molecular sieve is loaded.

2. The method according to claim 1, wherein: The mass content of the Y-type molecular sieve in the hydrocracking catalyst loaded in the Nth hydrocracking catalyst bed differs from the mass content of the Y-type molecular sieve in the hydrocracking catalyst loaded in the N+1th hydrocracking catalyst bed by 10-40%, preferably by 15-35%, and more preferably by 20-30%.

3. The method according to claim 1, wherein: The unit cell constant of the Y-type molecular sieve in the hydrocracking catalyst loaded in the N+1th hydrocracking catalyst bed is 0.001 to 0.012 nm different from the unit cell constant of the Y-type molecular sieve in the hydrocracking catalyst loaded in the Nth hydrocracking catalyst bed, preferably 0.004 to 0.010 nm, more preferably 0.006 to 0.008 nm lower.

4. The method according to claim 1, wherein: The active metal components in the hydrocracking catalyst are Group VIB metals and / or Group VIII metals, preferably tungsten (W) and molybdenum (Mo) among the Group VIB metals, and preferably cobalt (Co) and nickel (Ni) among the Group VIII metals. Based on the weight of the hydrocracking catalyst, the Group VIB metal (calculated as oxide) accounts for 8% to 25%; and the Group VIII metal (calculated as oxide) accounts for 1% to 7%.

5. The method according to claim 1, wherein: The hydrocracking catalyst bed is arranged in one hydrocracking reactor or in multiple hydrocracking reactors connected in series.

6. The method according to claim 1, wherein: The raw oil and hydrogen pass through the refined catalyst and enter the bed of the hydrocracking reactor. The reaction effluent passes through the high-pressure separator and the low-pressure separator to separate the gas and liquid components. The obtained liquid components are transported to the distillation tower for component separation in different distillation ranges to obtain light naphtha, heavy naphtha and hydrocracking unconverted oil.

7. The method according to claim 6, characterized in that: The properties of the raw oil are as follows: the density of the raw oil at 20°C is 0.8980-0.9180 g·cm -3 The initial distillation point is 290-340°C, the final distillation point is 500-550°C, and the sulfur content is 14,000-20,000 μg·g -1 , nitrogen content is 600~1000μg·g -1 ;.

8. The method according to claim 6, wherein: The mass proportion of the raw oil chain paraffins is 18-23%, the mass proportion of the total cycloparaffins is 32-37%, and the mass proportion of the total aromatics is 41-45%.

9. The method according to claim 6, wherein: The hydrofining reaction conditions are as follows: reaction pressure 10-18 MPa, hydrogen feedstock oil volume ratio 800:1-1500:

1. The internal temperature of the refining reactor bed is 320-420°C, and the volume space velocity is 0.8-2.0h -1 .

10. The method according to claim 6, wherein: The hydrocracking reaction conditions are as follows: reaction pressure 10-18 MPa, hydrogen feedstock oil volume ratio 800:1-1500:

1. The internal temperature of the cracking reactor bed is 340-400°C, and the volume space velocity is 1.0-2.0 h -1 .

11. The method according to claim 1, wherein: Four different hydrocracking catalysts were used and were respectively designated as hydrocracking catalyst A, hydrocracking catalyst B, hydrocracking catalyst C, and hydrocracking catalyst D; The Y-type molecular sieve content in hydrocracking catalyst A is 10-40% higher than that in hydrocracking catalyst B, preferably 15-35% higher; the Y-type molecular sieve content in hydrocracking catalyst B is 10-35% higher than that in hydrocracking catalyst C, preferably 15-30% higher; the Y-type molecular sieve content in hydrocracking catalyst C is 15-35% higher than that in hydrocracking catalyst D, preferably 20-30% higher; The unit cell constant of the Y-type molecular sieve in the hydrocracking catalyst A is 0.005-0.012 nm lower than the unit cell constant of the Y-type molecular sieve in the hydrocracking catalyst B, preferably 0.008-0.010 nm lower. The unit cell constant of the Y-type molecular sieve in the hydrocracking catalyst B is 0.004-0.010 nm lower than the unit cell constant of the Y-type molecular sieve in the hydrocracking catalyst C, preferably 0.006-0.008 nm lower. The unit cell constant of the Y-type molecular sieve in the hydrocracking catalyst C is 0.001-0.009 nm lower than the unit cell constant of the Y-type molecular sieve in the hydrocracking catalyst D, preferably 0.004-0.007 nm lower.

12. The method according to claim 11, wherein: The active metal components in the hydrocracking catalyst A are Group VIB metals and Group VIII metals, preferably tungsten (W) and molybdenum (Mo) as Group VIB metals, and preferably cobalt (Co) and nickel (Ni) as Group VIII metals; based on the weight percentage of the catalyst, alumina is 5% to 35%; the Group VIB metal (calculated as oxide) is 8% to 25%; the Group VIII metal (calculated as oxide) is 1% to 7%; the Y-type molecular sieve content is between 40% and 70%; the unit cell constant of the Y-type molecular sieve is between 2.425 and 2.435 nm; and the relative crystallinity is between 85% and 105%.

13. The method according to claim 11, wherein: The active metal components in the hydrocracking catalyst B are Group VIB metals and Group VIII metals, preferably tungsten (W) and molybdenum (Mo) as Group VIB metals, and preferably cobalt (Co) and nickel (Ni) as Group VIII metals; based on the weight percentage of the catalyst after calcination at 500°C for 4 hours, the content of alumina is 15% to 45%; the content of the Group VIB metal (calculated as oxide) is 8% to 25%; the content of the Group VIII metal (calculated as oxide) is 1% to 7%; the content of the Y-type molecular sieve is between 30% and 55%; the unit cell constant of the Y-type molecular sieve is between 2.430 and 2.438 nm; and the relative crystallinity is between 85% and 105%.

14. The method according to claim 11, wherein: The active metal components in the hydrocracking catalyst C are Group VIB metals and Group VIII metals, preferably tungsten (W) and molybdenum (Mo) as Group VIB metals, and preferably cobalt (Co) and nickel (Ni) as Group VIII metals. The catalyst weight percentage after calcination at 500° C. for 4 hours is as follows: alumina is 30% to 50%; the Group VIB metal (calculated as oxide) is 8% to 25%; the Group VIII metal (calculated as oxide) is 1% to 7%; the Y-type molecular sieve content is between 20% and 45%, preferably 25% to 40%; the unit cell constant of the Y-type molecular sieve is between 2.435 and 2.440 nm, and the relative crystallinity is between 85% and 105%.

15. The method according to claim 11, wherein: The active metal components in the hydrocracking catalyst D are Group VIB metals and Group VIII metals, preferably tungsten (W) and molybdenum (Mo) as Group VIB metals, and preferably cobalt (Co) and nickel (Ni) as Group VIII metals; based on the weight percentage of the catalyst after calcination at 500°C for 4 hours, the aluminum oxide content is 45% to 75%; the Group VIB metal (calculated as oxide) is 8% to 25%; the Group VIII metal (calculated as oxide) is 1% to 7%; the Y-type molecular sieve content is between 5% and 25%, preferably 9% to 21%; the unit cell constant of the Y-type molecular sieve is between 2.436 and 2.446 nm; and the relative crystallinity is between 85 and 105%.

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