Hydrocracking method

Abstract

The present invention relates to the field of hydrocracking processes, and discloses a hydrocracking method, which comprises: introducing middle distillate oil into a hydrocracking reaction unit containing a hydrocracking catalyst, and carrying out first hydrotreatment to obtain a reaction effluent I; introducing the reaction effluent I into a hydrofining reaction unit containing a hydrofining catalyst, and carrying out second hydrotreating to obtain a reaction effluent II; and separating the reaction effluent II. According to the method, the rocket kerosene product and / or the transformer oil product which can be used as special fuel can be obtained in a short process.

Description

Technical Field

[0001] This invention relates to the field of hydrocracking processes, and more specifically to a hydrocracking method. Background Technology

[0002] Aerospace fuel is a synthetic liquid hydrocarbon used in rocket engines and rocket-ramjet combined-engine systems. Its main characteristics are high density and high calorific value. With a fixed fuel tank volume, using high-density, high-calorific-value fuel can provide more propulsion power, significantly increasing the payload of the spacecraft.

[0003] Apparent consumption of refined diesel fuel has peaked and is declining year by year. The future promotion of hydrogen energy and new energy vehicles will further shrink the demand for traditional fuel oil. Middle distillates such as straight-run diesel, hydrocracked diesel, and hydrotreated diesel are important components of the diesel fuel mix. Using them directly as blending components results in low added value, and market demand is shrinking annually. Therefore, developing products that can convert middle distillates into specialized applications such as aerospace fuel and transformer oil is of significant practical importance for addressing excess automotive diesel production capacity and increasing product added value.

[0004] CN104804765A discloses a method for producing high-density, high-calorific-value kerosene from coal tar. The method first requires deep hydrorefining of coal tar with a final boiling point <350℃ in a fixed bed. The hydrorefined product with a boiling point of 190℃~280℃ is collected as the final product, while the product with a boiling point >280℃ is recycled back to the hydrorefining process for further reaction.

[0005] CN108865263A discloses a coal-based blended high-energy-density fuel and its preparation method. This method requires a combination of distillation separation, hydrocracking, hydrogenation upgrading, chemical synthesis, and blending to obtain the high-energy-density fuel.

[0006] CN103789034A discloses a method for producing high-density aviation kerosene through hydrogenation of low- and medium-temperature coal tar. This method uses low- and medium-temperature coal tar as raw material, first separating it into light and heavy fractions. The light fraction directly enters the hydrogenation reaction zone for reaction, and the reaction product enters a fractionation tower. The kerosene fraction, obtained at 140℃–290℃, enters the hydrorefining reaction zone, where it reacts with a catalyst containing amorphous silica-alumina and modified Y zeolite, and is then separated and fractionated to obtain high-density aviation kerosene.

[0007] CN104789260A discloses a method for producing rocket kerosene from coal tar. The method first requires cutting off a fraction with a boiling point of 190℃ to 300℃ from the coal tar, and then using this fraction for hydrorefining at a reaction pressure of 8.0MPa to 20.0MPa to separate a product with a boiling point of 190℃ to 280℃, thus obtaining the product fraction.

[0008] Overall, existing technologies for producing special products, including rocket kerosene, mainly use coal-based raw materials and obtain the target product through high-pressure deep refining. The production process is long and the investment and operating costs are high. There are fewer reports on technologies that use petroleum-based raw materials.

[0009] Therefore, developing methods to convert petroleum-based middle distillate oils into special-purpose products, including rocket kerosene and transformer oil, is of great practical significance for reducing excess capacity of automotive diesel fuel and increasing product added value. Summary of the Invention

[0010] The purpose of this invention is to solve the problems of limited raw material sources, complex production processes, and high investment and operating costs in the production of special-purpose products such as rocket kerosene and transformer oil.

[0011] To achieve the above objectives, the present invention provides a hydrocracking method, the method comprising: in the presence of a hydrogen-rich gas,

[0012] (1) The middle distillate oil is introduced into a hydrocracking reaction unit containing a hydrocracking catalyst for the first hydrocracking treatment to obtain reaction effluent I;

[0013] (2) The reaction effluent I is introduced into a hydrorefining reaction unit containing a hydrorefining catalyst for a second hydrorefining treatment to obtain reaction effluent II;

[0014] (3) Separate the reaction effluent II to obtain rocket kerosene product and / or transformer oil product;

[0015] The hydrocracking catalyst contains mesoporous molecular sieves with pore sizes ranging from 0.35 nm to 0.60 nm. The mesoporous molecular sieves have a crystallinity of 78%-95%, a silica-alumina ratio of 20-60, and a specific surface area of ​​270 g / m². 2 -380g / m 2 ;

[0016] The ratio of the packing volume of the hydrocracking catalyst to the packing volume of the hydrorefining catalyst is 4:1 to 2:1;

[0017] The reaction conditions of the first hydrotreating are controlled such that the conversion rate of alkanes in the middle distillate oil is 15%-35%.

[0018] In this invention, petroleum-based middle distillate oil is mainly used as raw material to broaden the raw material sources for the production process. The production process is simple: the middle distillate oil and hydrogen-rich gas are mixed and then reacted with a mesoporous hydrocracking catalyst and a hydrorefining catalyst, respectively. After separation and fractionation, the reaction products can be used to obtain products such as rocket kerosene and transformer oil.

[0019] The hydrocracking catalyst used in the method of the present invention contains a mesoporous molecular sieve with a pore size in the range of 0.35 nm to 0.60 nm. The mesoporous molecular sieve has a crystallinity of 78% to 95%, a silica-alumina ratio of 20 to 60, and a specific surface area of ​​270 g / m². 2 -380g / m 2 This allows the features in the method of the present invention to synergistically increase the density of rocket kerosene and achieve an appropriate degree of conversion of chain hydrocarbons in the feedstock. Furthermore, in the method of the present invention, the reaction conditions of the first hydrotreating are controlled so that the conversion rate of alkane hydrocarbons in the middle distillate oil is 15%-35%, and the loading volume ratio of the hydrocracking catalyst and the hydrorefining catalyst is controlled within a certain range, so that the method of the present invention can obtain a target product with qualified properties (qualified calorific value and aromatic content).

[0020] The method of this invention can produce high-energy-density aerospace fuels and specialty oils. Detailed Implementation

[0021] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0022] In this invention, the conversion rate of alkanes in the middle distillate oil = 100% * (alkanes content in the middle distillate oil - alkanes content in the >190℃ fraction of the reaction effluent I * mass fraction of the >190℃ fraction of the reaction effluent I / 100) / alkanes content in the middle distillate oil.

[0023] In this invention, "within the range" means including the endpoint values ​​of the range. For example, in the range of 0.35nm-0.60nm, it means including the two endpoint values ​​of 0.35nm and 0.60nm.

[0024] The average particle size mentioned in this invention refers to the average particle size by weight.

[0025] The silicon-aluminum ratio in this invention refers to the molar ratio of silicon oxide to aluminum oxide.

[0026] The average particle size mentioned in this invention refers to the average particle size by weight.

[0027] As previously stated, this invention provides a hydrocracking method, the method comprising: in the presence of a hydrogen-rich gas,

[0028] (1) The middle distillate oil is introduced into a hydrocracking reaction unit containing a hydrocracking catalyst for the first hydrocracking treatment to obtain reaction effluent I;

[0029] (2) The reaction effluent I is introduced into a hydrorefining reaction unit containing a hydrorefining catalyst for a second hydrorefining treatment to obtain reaction effluent II;

[0030] (3) Separate the reaction effluent II to obtain rocket kerosene product and / or transformer oil product;

[0031] The hydrocracking catalyst contains mesoporous molecular sieves with pore sizes ranging from 0.35 nm to 0.60 nm. The mesoporous molecular sieves have a crystallinity of 78%-95%, a silica-alumina ratio of 20-60, and a specific surface area of ​​270 g / m². 2 -380g / m 2 ;

[0032] The ratio of the packing volume of the hydrocracking catalyst to the packing volume of the hydrorefining catalyst is 4:1 to 2:1;

[0033] The reaction conditions of the first hydrotreating are controlled such that the conversion rate of alkanes in the middle distillate oil is 15%-35%.

[0034] The inventors discovered that by adjusting the reaction temperature of the first hydrotreating process within the range of 280℃-380℃, the synergistic effect of the technical features in this invention enables the conversion rate of alkanes in the middle distillate oil to 15%-35%. Preferably, the temperature of the first hydrotreating process is controlled to be 280℃-380℃.

[0035] Preferably, the reaction conditions of the second hydrogenation treatment are controlled such that the aromatic content of the >190°C fraction is 0-4.9 wt%.

[0036] More preferably, the temperature of the second hydrogenation treatment is controlled at 320°C-370°C, so that the aromatic content of the >190°C fraction is 0-4.9 wt%.

[0037] In a preferred embodiment, at least one hydrocracking protection catalyst is packed upstream of the hydrocracking catalyst in the hydrocracking reaction unit.

[0038] Preferably, the average particle size of the hydrogenation protection catalyst is in the range of 1.3 mm to 16 mm.

[0039] According to a preferred embodiment, the loading volume ratio of the hydrogenation protection catalyst to the hydrocracking catalyst is 1:7 to 1:17.

[0040] Preferably, the hydrogenation protection catalyst is selected from at least one of catalyst A having the following characteristics:

[0041] The catalyst A comprises a support and an active metal component. The support is alumina, and the active metal component contains at least one Group VIII metal element and at least one Group VIB metal element. The Group VIII metal element is nickel and / or cobalt, and the Group VIB metal element is molybdenum and / or tungsten. Based on the total weight of the catalyst A, the content of the Group VIII metal element, calculated as oxides, is 0.3wt%-5wt%, and the content of the Group VIB metal element is 1wt%-10wt%.

[0042] According to a particularly preferred embodiment, the upstream of the hydrocracking catalyst is loaded with three types of hydroprotective catalyst with different average particle sizes, and the loading volume ratio of the upstream hydroprotective catalyst, the midstream hydroprotective catalyst and the downstream hydroprotective catalyst is 1:1:1 to 1:2:4.

[0043] In a preferred embodiment, the mesoporous molecular sieve is selected from at least one of ZSM series molecular sieves, SAPO series molecular sieves, IM-5 molecular sieves, and MCM-22 molecular sieves.

[0044] Particularly preferred is that the mesoporous molecular sieve is ZSM-5 molecular sieve.

[0045] In a preferred embodiment, the hydrocracking catalyst further comprises a heat-resistant inorganic oxide and an active metal component. The heat-resistant inorganic oxide is selected from at least one of silicon oxide, aluminum oxide, and amorphous aluminum silicate. The active metal component comprises at least one Group VIII metal element and at least one Group VIB metal element. Based on the total weight of the hydrocracking catalyst, the content of the Group VIB metal element, calculated as oxide, is 15wt%-35wt%, and the content of the Group VIII metal element is 2wt%-8wt%.

[0046] More preferably, in the hydrocracking catalyst, based on the total weight of the heat-resistant inorganic oxide and the mesoporous molecular sieve, the content of the mesoporous molecular sieve is 20wt%-65wt%, and the balance is heat-resistant inorganic oxide.

[0047] According to a preferred embodiment, the conditions for the first hydrogenation treatment include: a hydrogen partial pressure of 2.0 MPa-8.0 MPa, a reaction temperature of 280°C-380°C, and a liquid hourly space velocity of 0.3 h⁻¹. -1 -5h -1 The hydrogen-to-oil volume ratio is 300-2000.

[0048] Preferably, the hydrorefining catalyst is selected from at least one of catalyst B having the following characteristics:

[0049] The catalyst B comprises a support and an active metal component. The support is at least one of an alumina support or an alumina-silica support. The active metal component contains at least one element selected from Group VIII and Group VIB metals. The Group VIII metal is nickel and / or cobalt, and the Group VIB metal is molybdenum and / or tungsten.

[0050] More preferably, in the catalyst B, the active metal component contains at least one Group VIII metal element and at least one Group VIB metal element, and based on the total weight of the catalyst B, the content of the Group VIII metal element is 1wt%-15wt% and the content of the Group VIB metal element is 5wt%-40wt% in terms of oxides.

[0051] In a preferred embodiment, the conditions for the second hydrogenation treatment include: a hydrogen partial pressure of 2.0 MPa-8.0 MPa, a reaction temperature of 290°C-390°C, and a liquid hourly space velocity of 0.3 h⁻¹. -1 -5h -1 The hydrogen-to-oil volume ratio is 300-2000.

[0052] Preferably, the middle distillate oil has a D-86 initial boiling point greater than or equal to 190°C, an aromatic content of 3wt%-20wt%, and a nitrogen content of ≤100μg / g.

[0053] Preferably, the middle distillate oil is selected from at least one of hydrotreated diesel, straight-run diesel, hydrocracked diesel, and hydrotreated modified diesel.

[0054] Preferably, the hydrogen component in the hydrogen-rich gas is 80%-99%.

[0055] Particularly preferably, the hydrogen sulfide concentration in the hydrogen-rich gas is 150 μL / L to 10000 μL / L.

[0056] The present invention will be described in detail below through examples. In the following examples, unless otherwise specified, the raw materials used are all commercially available products.

[0057] In the following examples, unless otherwise specified, the hydrogenation protection catalysts are RG-200, RG-30A, and RG-30B loaded sequentially in a 1:1:1 volume ratio. All three grades of protection catalysts were manufactured by Changling Catalyst Branch. The average particle size of RG-200 is 16 mm, that of RG-30A is 6 mm, and that of RG-30B is 3 mm.

[0058] In the following examples, unless otherwise specified, the commercial brand name of the hydrorefining catalyst is RJW-3, which is produced by Changling Catalyst Branch.

[0059] The mesoporous molecular sieve contained in the hydrocracking catalyst CAT-1 is ZSM-5 molecular sieve, with a specific surface area of ​​291 m². 2 The molecular sieve has a crystallinity of 80.6%, a silica-to-alumina ratio of 40.4, and a pore size range of 0.51 nm to 0.56 nm. The hydrocracking catalyst CAT-1 also contains heat-resistant inorganic oxides and active metal components. The heat-resistant inorganic oxide is alumina. In the hydrocracking catalyst CAT-1, the active metal element content, calculated as oxide, is 29.2 wt% (of which the nickel content is 4.5% and the molybdenum content is 24.7%), with the balance being the support. Based on the total weight of the support, the content of the mesoporous molecular sieve is 35 wt%, with the balance being heat-resistant inorganic oxides.

[0060] The mesoporous molecular sieve contained in the hydrocracking catalyst CAT-2 is MCM-22 molecular sieve, which has a specific surface area of ​​425 m². 2 The molecular sieve has a crystallinity of 67%, a silica-to-alumina ratio of 25.5, and a pore size range of 0.4 nm to 0.59 nm. The hydrocracking catalyst CAT-2 also contains heat-resistant inorganic oxides and active metal components. The heat-resistant inorganic oxide is alumina. In the hydrocracking catalyst CAT-2, the active metal element content, calculated as oxide, is 29.0 wt% (of which the nickel content, calculated as oxide, is 4.3 wt%, and the molybdenum content, calculated as oxide, is 24.7 wt%), with the balance being the support. Based on the total weight of the support, the content of the mesoporous molecular sieve is 30 wt%, with the balance being heat-resistant inorganic oxides.

[0061] In the following examples, unless otherwise specified, the packing volume ratio of the hydroprotection catalyst to the hydrocracking catalyst is 1:13; and the packing volume ratio of the hydrocracking catalyst to the hydrorefining catalyst is 3.07:1.

[0062] In the present invention, the definition of the naphtha fraction yield is: the weight percentage of the fraction with a temperature < T1°C cut from the whole fraction product through the fractionating tower to the raw material, where T1 is 165 - 200°C;

[0063] The property parameters of the following middle distillate oils are shown in Table 1. The property indicators of GJB5425 - 2005 rocket kerosene are shown in Table 4. The property requirements of GB2536 - 2011 general transformer oil are shown in Table 5.

[0064] Table 1: Properties of Middle Distillate Oils

[0065] project crude oil <![CDATA[Density (20 °C) / (g / cm 3 )]]> 0.8434 Sulfur mass fraction (μg / g) 48.4 Nitrogen content (μg / g) 3.1 Hydrocarbon composition, wt% Alkanes 26.6 Cycloalkanes 65.3 Aromatics 8.1 ASTM D-86 distillation range / ℃ IBP 203.4 50％ 270.3 FBP 316.4

[0066] Example 1, Example 2 and Comparative Example 1

[0067] Process flow:

[0068] The raw material oil is mixed with hydrogen (where the hydrogen sulfide concentration is 3000 μL / L, the same for the rest of the examples), and then successively contacts with the hydrogenation protection catalyst, the hydrocracking catalyst and the hydrofining catalyst for reaction. The reaction products are separated and fractionated to obtain the top naphtha, the rocket kerosene fraction and the bottom transformer oil fraction. The corresponding process condition parameters, product yields and property data are listed in Table 2.

[0069] Table 2

[0070]

[0071] From the data in Table 2, it can be seen that the reaction temperatures of the hydrocracking catalysts in Example 1 and Example 2 are 325°C and 354°C respectively, the reaction temperatures of the hydrofining catalysts are 330°C and 350°C respectively, the paraffin conversions of the middle distillate oils are 18.76% and 30.97% respectively, the aromatic hydrocarbon contents of the fractions > 190°C are 4.8 wt% and 3.42% respectively, the yields of the naphtha fractions < 190°C are 7.48% and 11.53% respectively, the yields of the rocket kerosene fractions at 190 - 270°C are 42.68% and 43.39% respectively, and the yields of the transformer oil fractions > 270°C are 49.84% and 45.08% respectively; the densities of the rocket kerosene fractions are 0.8351 g / cm 3 and 0.8346 g / cm 3 , the flash points (closed cup) are 73.5°C and 74.0°C respectively, the smoke points are 23.4 mm and 23.9 mm respectively, the crystallinities all meet < -60°C, the net calorific values are 42.90 MJ / kg and 42.92 MJ / kg respectively, and the product properties meet the property requirements of GJB5425 - 2005 rocket kerosene; the densities of the transformer oil fractions > 270°C of the products are 0.8527 g / cm 3 and 0.8563 g / cm 3The flash points (closed cup) are 136℃ and 137℃, respectively, and the kinematic viscosity at 40℃ is 4.820 mm. 2 / s and 4.921mm 2 The concentrations are / s, with pour points of -37℃ and -57℃ respectively, and the mass fraction of polycyclic aromatic hydrocarbons (PCA) is <1.0%, which meets the property index requirements of transformer oil at -20℃ and -40℃ in GB2536-2011 general transformer oil.

[0072] The above results demonstrate that the method provided by this invention can produce rocket kerosene and transformer oil products with qualified properties.

[0073] The data in Table 2 also show that the alkanes conversion rate of the middle distillate oil in Comparative Example 1 was 12.61%, and the aromatics content of the >190℃ fraction was 7.9 wt%. The corresponding rocket kerosene fraction had a low net calorific value of only 42.89 MJ / kg and a high aromatics content of 7.4%, failing to meet the requirements for qualified rocket kerosene properties. Due to the low alkanes conversion rate of the raw material, the pour point of the >270℃ transformer oil fraction was only -27℃, making it only suitable as -10 transformer oil.

[0074] Examples 3 and 4

[0075] Examples 3 and 4 used the same raw materials and catalyst scheme as Example 1. The feed oil was mixed with hydrogen and then reacted sequentially with a hydroprotection catalyst, a hydrocracking catalyst, and a hydrorefining catalyst. The reaction products were separated and fractionated to obtain naphtha fraction, rocket kerosene fraction, and transformer oil fraction. The corresponding process conditions, product yields, and product property data are listed in Table 3.

[0076] Table 3

[0077]

[0078]

[0079] Table 3 shows that the reaction temperatures of the hydrocracking catalysts in Examples 3 and 4 were 317℃ and 339℃, respectively, and the reaction temperatures of the hydrorefining catalysts were 325℃ and 340℃, respectively. The corresponding alkane conversion rates of the feedstock (middle distillate oil) were 15.43% and 24.49%, respectively. The yields of naphtha fractions at <190℃ were 6.37% and 9.38%, respectively; the yields of rocket kerosene fractions were 42.48% and 43.02%, respectively; and the yields of transformer oil fractions from the bottom of the tower were 51.14% and 47.60%, respectively. The densities of the rocket kerosene fractions were 0.8357 g / cm³. 3 and 0.8349 g / cm 3The flash points (closed cup) are 69.0℃ and 70.0℃, respectively; the smoke points are 23.1mm and 23.7mm, respectively; the crystallinity meets the requirement of <-60℃; the net calorific value is 42.90MJ / kg and 42.91MJ / kg, respectively; and the product properties meet the requirements of GJB5425-2005 rocket kerosene property indicators. The density of the transformer oil fraction above 270℃ is 0.8517g / cm³. 3 and 0.8544 g / cm 3 The flash points (closed cup) are 136℃ and 137℃, respectively, and the kinematic viscosity at 40℃ is 4.5663 mm. 2 / s and 5.256mm 2 The concentrations are 1.0% / s, with pour points of -31℃ and -47℃ respectively, and the mass fraction of polycyclic aromatic hydrocarbons (PCA) is <1.0%, which meets the property index requirements of transformer oil at -20℃ and -30℃ in GB2536-2011 general transformer oil.

[0080] Table 4: Properties of Rocket Kerosene (GJB5425-2005)

[0081] project Kerosene Ex-factory Specifications <![CDATA[Density (20 °C) / (kg / m 3 )]]> 830.0～836.0 Distillation range (D-86) / ℃ Initial boiling point ≥188 10％ ≤215 50％ ≤235 90％ ≤260 Final boiling point ≤270 Flash point (closed cup) / °C ≥60 Crystallization point / ℃ ≤-60 Aromatic hydrocarbon content / % (m / m) ≤5.0

[0082] Table 5: Requirements for the Properties of Transformer Oil in GB2536-2011

[0083]

[0084] Example 5

[0085] Example 5 follows the process flow of Example 1, except that the same volume of RG-30S (hydrogenation protection catalyst, with an average particle size of 25 mm) is used to replace RG-200 in Example 1. The feedstock oil is mixed with hydrogen and then reacted sequentially with the hydroprotection catalyst, the hydrocracking catalyst, and the hydrorefining catalyst. The reaction products are separated and fractionated to obtain naphtha fraction, rocket kerosene fraction, and transformer oil fraction. The corresponding process conditions, product yields, and product property data are listed in Table 6.

[0086] Example 6

[0087] Example 6 follows the process flow of Example 1. The total loading volume of the hydrogenation protection catalyst and the hydrocracking catalyst in Example 6 is the same as that in Example 1. The difference is that the loading volume ratio of the hydrogenation protection catalyst and the hydrocracking catalyst in Example 6 is 1:2. The specific process conditions, product yield and product property data are listed in Table 6.

[0088] Comparative Example 2

[0089] Comparative Example 2 follows the process flow of Example 1. The total packing volume of the hydrocracking catalyst and the hydrorefining catalyst in Comparative Example 2 is the same as that in Example 1. The difference is that the packing volume ratio of the hydrocracking catalyst and the hydrorefining catalyst in Comparative Example 2 is 8:1. The specific process conditions, product yield and product property data are listed in Table 6.

[0090] Comparative Example 3

[0091] Comparative Example 3 follows the process flow of Example 1, except that the same volume of hydrocracking catalyst CAT-2 is used to replace the hydrocracking catalyst CAT-1 in Example 1. The specific process conditions, product yield, and product property data are listed in Table 6.

[0092] Table 6

[0093]

[0094]

[0095] As shown in Table 6, rocket kerosene and transformer oil fractions with acceptable properties were obtained in Example 5. However, the material distribution in the hydrocracking catalyst bed in Example 5 was not good, which reduced the utilization efficiency of the cracking catalyst bed and resulted in a higher reaction temperature.

[0096] As shown in Table 6, rocket kerosene and transformer oil fractions with acceptable properties can be obtained in Example 6. However, the hydrocracking and hydrorefining catalysts in this scheme have high volume hourly space velocities, requiring higher reaction temperatures for activity compensation, which shortens the catalyst operating cycle and slightly reduces the reaction efficiency and product selectivity.

[0097] As shown in Table 6, the aromatic content of the rocket kerosene fraction in Comparative Example 2 increased significantly, and the product quality could not meet the requirements for qualified products.

[0098] As shown in Table 6, the density of the rocket kerosene fraction in Comparative Example 3 decreased, while the pour point of the transformer oil fraction increased, indicating that the product quality could not meet the requirements for qualified products.

[0099] The above results demonstrate that the method provided by this invention can produce rocket kerosene and transformer oil products with satisfactory properties. Furthermore, the method of this invention can yield transformer oil products with a high yield.

[0100] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A hydrocracking process characterized by, The method comprises: (1) introducing the middle distillate oil into a hydrocracking reaction unit containing a hydrocracking catalyst to perform a first hydroprocessing to obtain a reaction effluent I; (2) introducing the reaction effluent I into a hydrofining reaction unit containing a hydrofining catalyst to perform a second hydroprocessing to obtain a reaction effluent II; (3) separating the reaction effluent II to obtain a rocket kerosene product and / or a transformer oil product; The hydrocracking catalyst contains mesoporous molecular sieve with pore diameter in the range of 0.35nm-0.60nm, the crystallinity of the mesoporous molecular sieve is 78%-95%, the silicon-aluminum ratio is 20-60, the specific surface area is 270g / m 2 -380g / m 2 ; The ratio of the packing volume of the hydrocracking catalyst to the packing volume of the hydrofining catalyst is 4:1 to 2:1; The reaction conditions of the first hydroprocessing are controlled so that the conversion rate of paraffins in the middle distillate oil is 15%-35%.

2. The hydrocracking process of claim 1 wherein, The temperature of the first hydroprocessing is controlled to be 280°C-380°C.

3. The hydrocracking process of claim 1 or 2, characterized in that, The reaction conditions of the second hydroprocessing are controlled so that the aromatic content of the >190°C fraction is 0-4.9wt%. Preferably, the temperature of the second hydroprocessing is controlled to be 320°C-370°C.

4. The hydrocracking process of any of claims 1-3, wherein, In the hydrocracking reaction unit, at least one hydrogenation protection catalyst is packed upstream of the hydrocracking catalyst; Preferably, the average particle size of the hydrogenation protection catalyst is in the range of 1.3mm-16mm.

5. The hydrocracking process of claim 4, wherein, The packing volume ratio of the hydrogenation protection catalyst to the hydrocracking catalyst is 1:7 to 1:

17.

6. The hydrocracking process of claim 4, wherein, The hydrogenation protection catalyst is selected from at least one of catalyst A having the following characteristics: The catalyst A comprises a carrier and an active metal component, the carrier is alumina, the active metal component contains at least one Group VIII metal element and at least one Group VIB metal element, the Group VIII metal element is nickel and / or cobalt, and the Group VIB metal element is molybdenum and / or tungsten; based on the total weight of the catalyst A, the content of the Group VIII metal element is 0.3wt%-5wt%, and the content of the Group VIB metal element is 1wt%-10wt%.

7. The hydrocracking process of any of claims 1-6, wherein, The mesoporous molecular sieve is selected from at least one of ZSM series molecular sieves, SAPO series molecular sieves, IM-5 molecular sieves, and MCM-22 molecular sieves; Preferably, the mesoporous molecular sieve is ZSM-5 molecular sieve.

8. The hydrocracking process of any of claims 1-7, wherein, The hydrocracking catalyst also contains a heat-resistant inorganic oxide and an active metal component, the heat-resistant inorganic oxide is selected from at least one of silicon oxide, aluminum oxide, and amorphous aluminum silicate; the active metal component contains at least one Group VIII metal element and at least one Group VIB metal element; based on the total weight of the hydrocracking catalyst, the content of the Group VIB metal element is 15wt%-35wt%, and the content of the Group VIII metal element is 2wt%-8wt%.

9. The hydrocracking process of claim 8, wherein, In the hydrocracking catalyst, based on the total weight of the heat-resistant inorganic oxide and the mesoporous molecular sieve, the content of the mesoporous molecular sieve is 20wt%-65wt%, and the balance is heat-resistant inorganic oxide.

10. The hydrocracking process of any of claims 1-9, wherein, The conditions of the first hydroprocessing include: hydrogen partial pressure of 2.0-8.0 MPa, reaction temperature of 280-380℃, liquid hourly space velocity of 0.3-1.5 h -1 -5 h -1 , hydrogen to oil volume ratio of 300-2000.

11. The hydrocracking process of any of claims 1-10, wherein, The hydrofining catalyst is selected from at least one of catalyst B having the following characteristics: The catalyst B comprises a carrier and an active metal component, the carrier is at least one of alumina carrier, alumina-silica carrier, the active metal component contains at least one element selected from group VIII metal element, group VIB metal element, the group VIII metal element is nickel and / or cobalt, the group VIB metal element is molybdenum and / or tungsten; Preferably, in the catalyst B, the active metal component contains at least one group VIII metal element and at least one group VIB metal element, the content of the group VIII metal element is 1wt%-15wt% and the content of the group VIB metal element is 5wt%-40wt% based on the total weight of the catalyst B in terms of oxide.

12. The hydrocracking process of any of claims 1-11, wherein, The conditions of the second hydroprocessing include: hydrogen partial pressure of 2.0-8.0 MPa, reaction temperature of 290-390°C, liquid hourly space velocity of 0.3-1.5 h -1 -5 h -1 , hydrogen to oil volume ratio of 300-2000.

13. The hydrocracking process of any of claims 1-12, wherein, The D-86 initial boiling point of the middle distillate oil is greater than or equal to 190℃, the aromatic hydrocarbon content is 3wt%-20wt%, and the nitrogen content satisfies ≯100μg / g.

14. The hydrocracking process of any of claims 1-13, wherein, The middle distillate oil is selected from at least one of hydrofining diesel oil, straight-run diesel oil, hydrocracking diesel oil, hydro-upgrading diesel oil.

15. The hydrocracking process of any of claims 1-14, wherein, The hydrogen volume fraction in the hydrogen-rich gas is 80%-99%; Preferably, the hydrogen sulfide concentration in the hydrogen-rich gas is 150μL / L-10000μL / L.

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