A method for producing specialty oils

Abstract

The present application relates to the technical field of special oil production, and discloses a method for producing special oil, which comprises the following steps: introducing raw oil and hydrogen-containing gas into a hydrofining reaction zone containing a hydrofining catalyst I to perform a hydrofining reaction, so as to obtain a refined reaction effluent; introducing the refined reaction effluent into a hydrocracking reaction zone containing a hydrocracking catalyst to perform a hydrocracking reaction, so as to obtain a cracked reaction effluent; introducing the cracked reaction effluent into a supplementary hydrofining reaction zone containing a hydrofining catalyst II to perform a supplementary hydrofining reaction, so as to obtain a supplementary hydrofining reaction effluent; and separating the supplementary hydrofining reaction effluent, so as to obtain a naphtha fraction and a special oil fraction. The method provided by the present application has the advantages of simple process, low investment and operation cost, and can produce a plurality of types of special oil products at a high yield.

Description

Technical Field

[0001] This invention relates to the field of specialty oil production technology, and specifically to a method for producing specialty oil products. Background Technology

[0002] Low-quality secondary processed diesel, represented by catalytic diesel, is an important component of the diesel fuel pool, accounting for about 30%. The production of automotive diesel blending components from catalytic diesel through hydrogenation not only has high hydrogen consumption but also low added value. Specialty oil products, represented by high-density jet fuel, cryogenic switching oil, and heat transfer oil, have high added value. Developing processing methods to produce specialty oil products from secondary processed oils, represented by low-quality catalytic diesel, is of great practical significance for improving the added value of low-quality secondary processed diesel.

[0003] CN110540875A discloses a method for producing high-density jet fuel and clean diesel. The method involves first extracting aromatics from low-quality diesel to obtain extracted oil and raffinate. The raffinate is then reacted in a hydrorefining reaction zone to obtain clean diesel, while the extracted oil is reacted in a hydrocracking reaction zone filled with phosphorus-containing Y-type molecular sieves to obtain naphtha, high-density jet fuel, and unconverted diesel. The yield of the high-density jet fuel fraction is 30% to 58%.

[0004] CN105733670A discloses a method for producing high-density aviation kerosene by hydrogenating catalytic refining oil. In this method, the catalytic refining oil is sequentially reacted with a hydrorefining catalyst, a hydromodification catalyst containing amorphous silicon and aluminum and modified Y zeolite, and a post-refining catalyst to obtain high-density aviation kerosene fraction and low-pour-point diesel fraction. However, this method does not disclose the calorific value properties of high-density aviation kerosene.

[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] CN113528181A discloses a combined method for producing heavy aviation kerosene. In this method, hydrogen is first mixed with heavy feedstock and then introduced into a hydrotreating reaction zone for contact reaction. The organic nitrogen content of the reaction effluent is controlled to be 50-600 μg / g. The hydrotreating effluent then reacts with a phosphorus-containing molecular sieve hydrocracking catalyst in a hydrocracking reaction zone. The reaction effluent is cut into a fraction at 180-215℃, thus yielding a product with a density of approximately 0.830 g / cm³. 3 It is aviation kerosene, but the kerosene fraction cannot meet the property index requirements of No. 6 high-density jet fuel.

[0008] Overall, existing technologies for producing specialty oils, including high-density jet fuel, require multiple processes, resulting in high equipment investment costs and long production processes. Furthermore, due to the primary use of Y-type molecular sieve cracking agents, the overall yield of high-density aviation kerosene fractions is not high.

[0009] Furthermore, there are few publicly disclosed technologies for producing cryogenic switching oils and heat transfer oils from secondary processed oils, such as catalytic diesel. Therefore, developing production methods that can convert inferior catalytic diesel into specialty oil products, including high-density jet fuel, cryogenic switching oils, and heat transfer oils, is of significant practical importance. Summary of the Invention

[0010] The purpose of this invention is to overcome the shortcomings of existing technologies in the production of specialty oil products, such as complex production processes and low yields.

[0011] To achieve the above objectives, the present invention provides a method for producing specialty oils, the method comprising:

[0012] (1) The feed oil and hydrogen-containing gas are introduced into the hydrotreatment reaction zone containing hydrorefining catalyst I to carry out the hydrorefining reaction and obtain the refined reaction effluent.

[0013] (2) The refined reaction effluent is introduced into a hydrocracking reaction zone containing a hydrocracking catalyst to carry out a hydrocracking reaction to obtain a cracking reaction effluent; the hydrocracking catalyst contains a mesoporous molecular sieve, wherein the mesoporous volume ratio of the mesoporous molecular sieve accounts for 15% to 60% of the total pore volume ratio of the mesoporous molecular sieve.

[0014] (3) The cracking reaction effluent is introduced into a supplementary refining reaction zone containing hydrorefining catalyst II for supplementary refining reaction to obtain supplementary refining reaction effluent; the hydrorefining catalyst II does not contain acidic components; the conditions of the supplementary refining reaction zone are controlled so that the aromatic saturation of the feedstock is 90% to 99%; the aromatic saturation of the feedstock is = 100% × (aromatic content in the feedstock - yield of the >175℃ fraction in the cracking reaction effluent × aromatic content of the >175℃ fraction in the cracking reaction effluent / 100%) / aromatic content in the feedstock;

[0015] (4) The supplementary refining reaction effluent is separated to obtain naphtha fraction and special oil fraction.

[0016] The method provided by this invention has the advantages of simple process, low investment and operating costs, and the ability to produce a wide variety of specialty oil products, and can produce specialty oil products with high yield. Detailed Implementation

[0017] 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.

[0018] In this invention, "mesoporous" in the mesoporous molecular sieve refers to pores with a diameter range of 0.35 nm to 0.60 nm. The pore size of the molecular sieve is tested in accordance with SH / T 0572-1993 Catalyst Pore Size Distribution Calculation Method (Nitrogen Desorption Isotherm Calculation Method).

[0019] In this invention, the "mesopore" volume refers to the pore volume excluding the micropore volume. The micropore volume is the sum of the volumes of pores with a radius less than 1 nm, and is generally related to the zeolite content in the catalyst. It is determined by the intercept of the Vt plot, i.e., V 介孔体积 =V 孔体积 -V 微孔体积 The pore volume and micropore volume were measured using the methods described above, and the surface area of ​​catalysts and adsorbents was measured using GB / T 5816-1995.

[0020] As mentioned above, the present invention provides a method for producing specialty oils, the method comprising:

[0021] (1) The feed oil and hydrogen-containing gas are introduced into the hydrotreatment reaction zone containing hydrorefining catalyst I to carry out the hydrorefining reaction and obtain the refined reaction effluent.

[0022] (2) The refined reaction effluent is introduced into a hydrocracking reaction zone containing a hydrocracking catalyst to carry out a hydrocracking reaction to obtain a cracking reaction effluent; the hydrocracking catalyst contains a mesoporous molecular sieve, wherein the mesoporous volume ratio of the mesoporous molecular sieve accounts for 15% to 60% of the total pore volume ratio of the mesoporous molecular sieve.

[0023] (3) The cracking reaction effluent is introduced into a supplementary refining reaction zone containing hydrorefining catalyst II for supplementary refining reaction to obtain supplementary refining reaction effluent; the hydrorefining catalyst II does not contain acidic components; the conditions of the supplementary refining reaction zone are controlled so that the aromatic saturation of the feedstock is 90% to 99%; the aromatic saturation of the feedstock is = 100% × (aromatic content in the feedstock - yield of the >175℃ fraction in the cracking reaction effluent × aromatic content of the >175℃ fraction in the cracking reaction effluent / 100%) / aromatic content in the feedstock;

[0024] (4) The supplementary refining reaction effluent is separated to obtain naphtha fraction and special oil fraction.

[0025] In this invention, the feedstock oil is preferably a low-quality secondary processed diesel feedstock oil.

[0026] In this invention, the final boiling point of the naphtha fraction is 165–205°C, preferably 165–185°C.

[0027] The special oil fractions described in this invention include, but are not limited to, high-density jet fuel, cryogenic switching oil, organic heat transfer fluid, and refrigeration oil.

[0028] In this invention, the inventors discovered that, in order to reduce the ring-opening of monocyclic and bicyclic hydrocarbon components while converting tricyclic and higher-ring hydrocarbon components, a mesoporous molecular sieve is packed in the hydrocracking reaction zone. This mesoporous molecular sieve contains a certain amount of mesopores to improve the accessibility of tricyclic and higher-ring hydrocarbon molecules to the active center, wherein the mesopore volume ratio accounts for 15% to 60% of the total pore volume. Furthermore, the conditions in the supplementary refining reaction zone are controlled so that the aromatic saturation rate of the feedstock oil is 90% to 99%; the aromatic saturation rate of the feedstock oil = 100% × (aromatic content in the feedstock oil - yield of >175℃ fraction in the cracking effluent × aromatic content of >175℃ fraction in the cracking effluent / 100%) / aromatic content in the feedstock oil. The inventors also discovered that, to meet the property index requirements of specialty oil products, supplementary refining of the cracking product oil is performed, and the aromatic saturation rate of the feedstock oil is controlled to 90% to 99% through the supplementary refining reaction zone.

[0029] In a preferred embodiment, the loading volume ratio of the hydrorefining catalyst I to the hydrorefining catalyst II is 5:1 to 2:1.

[0030] According to a preferred embodiment, the hydrorefining catalyst I and the hydrorefining catalyst II are each independently selected from at least one of the hydrorefining catalysts A; the hydrorefining catalyst A contains a support A and an active metal component supported on the support A, wherein the support A is alumina and / or alumina-silica, and the active metal component contains at least one element selected from Group VIB metals and / or at least one element selected from Group VIII metals.

[0031] Preferably, in the hydrorefining catalyst A, the Group VIII metal is selected from nickel and / or cobalt; the Group VIB metal is selected from molybdenum and / or tungsten.

[0032] More preferably, in the hydrorefining catalyst A, based on the total weight of the hydrorefining catalyst A, the content of the Group VIII metal element is 1 wt% to 15 wt% and the content of the Group VIB metal element is 5 wt% to 40 wt% (calculated as oxides).

[0033] In a preferred embodiment, to reduce uncontrolled ring-opening cracking reactions during the raw material refining process, neither the hydrorefining catalyst I nor the hydrorefining catalyst II contains acidic components, which include P and F.

[0034] Particularly preferably, the conditions of the hydrogenation reaction zone are controlled (e.g., by adjusting the reaction pressure, reaction temperature, volume hourly space velocity, and hydrogen-to-oil volume ratio) so that the nitrogen content in the refined reaction effluent is <20 μg / g.

[0035] Preferably, the reaction conditions in the hydrogenation reaction zone include: a reaction pressure of 10.0 MPa to 16.0 MPa, a reaction temperature of 290°C to 420°C, and a liquid hourly space velocity of 0.3 h⁻¹. -1 ~5h -1 The hydrogen-to-oil volume ratio is 300–2000.

[0036] According to a preferred embodiment, the hydrocracking catalyst includes a support B and an active metal component supported on the support B, wherein the support B is composed of a heat-resistant inorganic oxide and the mesoporous molecular sieve.

[0037] More preferably, in the hydrocracking catalyst, the heat-resistant inorganic oxide is selected from at least one of silicon oxide, aluminum oxide, and amorphous aluminum silicate.

[0038] In a preferred embodiment, the active metal component in the hydrocracking catalyst contains at least two elements selected from Group VIB and Group VIII metals; based on the total weight of the hydrocracking catalyst, the content of the Group VIB metal is 15 wt% to 35 wt% and the content of the Group VIII metal is 2 wt% to 8 wt% (calculated as oxides).

[0039] Preferably, in the hydrocracking catalyst, based on the total weight of the support B, the content of the mesoporous molecular sieve is 20wt% to 65wt%, and the balance is heat-resistant inorganic oxide.

[0040] In a particularly preferred embodiment, the mesoporous molecular sieve in the hydrocracking catalyst is selected from at least one of the ZSM series molecular sieves, SAPO series molecular sieves, IM-5 molecular sieves, and MCM-22 molecular sieves.

[0041] Particularly preferred is that the mesoporous molecular sieve is ZSM-5 molecular sieve.

[0042] Preferably, the reaction conditions in the hydrocracking reaction zone include: a reaction pressure of 10.0 MPa to 16.0 MPa, a reaction temperature of 290°C to 420°C, and a liquid hourly space velocity of 0.3 h⁻¹. -1 ~5h -1 The hydrogen-to-oil volume ratio is 300–2000.

[0043] Furthermore, to obtain specialty oil products with further improved yields while ensuring that the cracked products meet the quality requirements of specialty oil products, the conversion rate of the feedstock oil in the hydrocracking reaction zone can be controlled between 8% and 20% by adjusting parameters such as reaction temperature, volume hourly space velocity, and hydrogen-to-oil volume ratio. Therefore, preferably, the conditions of the hydrocracking reaction zone are controlled such that the conversion rate of the feedstock oil is 8% to 20%; the conversion rate of the feedstock oil = 100% × (mass of naphtha fraction <175℃ in the cracking effluent / mass of the feedstock oil).

[0044] Preferably, the reaction conditions in the supplementary purification reaction zone include: a reaction pressure of 10.0 MPa to 16.0 MPa, a reaction temperature of 320°C to 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.

[0045] Preferably, the feedstock oil has an initial boiling point of D-86 of ≥175℃, a final boiling point of D-86 of 310-350℃, and a total content of cycloalkanes and aromatics of ≥80wt%.

[0046] More preferably, the feedstock oil is selected from at least one of catalytic cracking unit diesel, ebullated bed hydrocracking unit diesel, coker diesel, and naphthenic crude oil diesel fraction.

[0047] The present invention will be described in detail below through examples. In the following examples:

[0048] The definition of the naphtha fraction yield is: the weight percentage of the <T1°C fraction cut from the full-range product through a fractionation tower relative to the feedstock, where T1 is 165 to 185°C.

[0049] Unless otherwise specified, the commercial grade of the refining catalyst used in the hydrotreating reaction zone and the post-refining reaction zone is RJW-3. The support of this catalyst does not contain acidic components such as P and F, and it is produced by Sinopec Catalyst Company.

[0050] The loading volume ratio of the refining catalysts in the hydrotreating reaction zone and the post-refining reaction zone is 3.65:1.

[0051] Hydrocracking catalyst CAT-1: ZSM-5 molecular sieve with adjusted silica-alumina ratio is adopted, and the specific surface area of the molecular sieve is 291m 2 / g, the total pore volume is 0.158mL / g, of which the mesopore volume is 0.031mL / g, and the mesopore volume accounts for 19.6% of the total pore volume. The active metal elements in the hydrocracking catalyst are Ni and Mo, the total content of active metal components calculated as oxides is 28wt%, wherein the nickel oxide content is 4.5wt%, and the molybdenum oxide content is 15.5wt%; in the hydrocracking catalyst, based on the total weight of the support, the content of the mesoporous molecular sieve is 35wt%, and the balance is a heat-resistant inorganic oxide (the specific type is alumina).

[0052] Hydrocracking catalyst CAT-2: ZSM-5 molecular sieve is subjected to pore-enlarging modification with alkali metal to obtain mesopore-containing ZSM-5 molecular sieve, and the specific surface area of the modified mesopore-containing ZSM-5 molecular sieve is 371m 2 / g, the total pore volume is 0.303mL 3 / g, of which the mesopore volume is 0.201mL / g, and the mesopore volume accounts for 66.3% of the total pore volume. This molecular sieve is prepared according to the same formula as hydrocracking catalyst CAT-1, that is, the content of the molecular sieve in the support and the content of the metal oxides are equivalent to those of hydrocracking catalyst CAT-1, and hydrocracking catalyst CAT-2 is prepared according to the same method.

[0053] Hydrocracking catalyst CAT-3: Hydrocracking catalyst CAT-3 uses the same ZSM-5 molecular sieve as CAT-1; the amount of molecular sieve added is adjusted so that, based on the total weight of the support, the content of mesoporous molecular sieve is 8 wt%, and the balance is heat-resistant inorganic oxide (specifically alumina); using the same metal oxide loading as hydrocracking catalyst CAT-1, hydrocracking catalyst CAT-3 is prepared according to the same preparation method.

[0054] The properties of the feedstock oils used below are shown in Table 1. The properties of No. 6 high-density jet fuel are shown in Table 6. The property requirements for cryogenic switching oils according to GB 2536-2011 are shown in Table 7. The property requirements for organic heat transfer fluids according to GB 23971-2009 are shown in Table 8.

[0055] Table 1

[0056] project crude oil <![CDATA[Density (20℃) / (g / cm 3 [[ID=2>)]]> 0.9401 Sulfur mass fraction (μg / g) 965 Nitrogen content (μg / g) 225 Hydrocarbon composition, wt% Alkanes 11.6 Cycloalkanes 9.2 Aromatics 79.2 ASTM D-86 distillation range / ℃ IBP 192.5 50％ 252.6 FBP 318.8

[0057] Example 1, Example 2 and Comparative Example 1

[0058] Example 1, Example 2 and Comparative Example 1 used the same raw materials, process flow and catalyst scheme. The feed oil was mixed with hydrogen and then sequentially hydrotreated reaction zone, hydrocracking reaction zone and supplementary refining reaction zone and reacted with catalyst. The reaction effluent was separated and fractionated to obtain naphtha fraction and high specific gravity jet fuel special oil fraction. The corresponding process condition parameters and product yield and property data are listed in Table 2.

[0059] Table 2

[0060]

[0061] As shown in Table 2, the nitrogen content of the refined oil in the hydrotreating reaction zone of Examples 1 and 2 was 14 μg / g and 12 μg / g, respectively. The conversion rates in the hydrocracking reaction zone were controlled at 15.71% and 18.95%, respectively. The aromatic saturation rates of the feedstock in the supplementary refining reaction zone were 93.4% and 90.7%, respectively. The corresponding weight yields of the high-density jet fuel fraction were 84.29% and 81.05%, respectively, and the densities were 0.8494 g / cm³, respectively. 3 and 0.8532 g / cm 3 The smoke point is ≥21 mm, the freezing point is ≥-47℃, and the net calorific value is ≥42.9 MJ / kg. These results indicate that the method provided by this invention can obtain high-density jet fuel fractions with a weight yield ≥80% and satisfactory properties.

[0062] The data in Table 2 also show that, except for the difference in the supplementary refining reaction zone, the process conditions of Comparative Example 1 are the same as those of Example 1. The nitrogen content of the refined oil in the hydrotreating reaction zone of Comparative Example 1 is 12 μg / g, the conversion rate in the hydrocracking reaction zone is 15.60%, and the aromatic saturation rate of the feedstock in the supplementary refining reaction zone is 85.1%. Although Comparative Example 1 can obtain high-density jet fuel with a yield of 84.40%, the insufficient aromatic saturation depth of the feedstock in the supplementary refining reaction zone results in an excessively high aromatic content of 14.0% in the product. The aromatic content, smoke point, and net calorific value of the product do not meet the requirements of the property indicators of high-density jet fuel.

[0063] Example 3 and Example 4

[0064] Examples 3 and 4 use the same raw materials, process flow and catalyst scheme as Example 1. The feed oil is mixed with hydrogen and then sequentially hydrogenated, hydrocracking, and supplementary refining reaction zones and reacted with the catalyst. The reaction effluent is separated and fractionated to obtain naphtha fraction and special oil fraction. The corresponding process conditions, product yield and property data are listed in Table 3.

[0065] Table 3

[0066]

[0067]

[0068] Table 3 shows that in Examples 3 and 4, the nitrogen content of the refined oil in the hydrotreating reaction zone was controlled at 14 μg / g and 12 μg / g, respectively; the conversion rate in the hydrocracking reaction zone was controlled at 15.71% and 15.65%; and the aromatic saturation rate of the feedstock in the supplementary refining reaction zone was controlled at 93.4% and 92.4%, respectively. The corresponding weight yields of the 175℃~240℃ fraction were 61.35% and 61.20%, respectively, and the product properties met the requirements for high-density jet fuel properties. In Examples 3 and 4, the flash point (closed cup) of the >240℃ special oil fraction was 118.5℃ and 119℃, respectively; the pour point and cloud point both met the requirement of ≤-50℃; and the kinematic viscosity at 40℃ was 3.5 mm. 2 / s, simultaneously meeting the property requirements of organic heat transfer fluid and cryogenic switch oil.

[0069] Comparative Example 2, Example 5 and Example 6

[0070] Comparative Examples 2, 5, and 6 used the same raw materials and process flow as Example 1. The feedstock oil was mixed with hydrogen and then sequentially hydrotreated in the reaction zone, hydrocracking reaction zone, and supplementary refining reaction zone, reacting with the catalyst. The reaction effluent was separated and fractionated to obtain naphtha fraction and specialty oil fraction. The corresponding process parameters, product yields, and properties are listed in Table 4. The specific differences are listed below:

[0071] In Comparative Example 2: the hydrocracking catalyst in the hydrocracking reaction zone was CAT-2, and the packing volume was the same as that of CAT-1 in Example 1.

[0072] In Example 5, the volume ratio of the refined catalyst in the hydrogenation reaction zone to the supplementary refining reaction zone is 6:1, and the total volume of the refined catalyst in the hydrogenation reaction zone and the supplementary refining reaction zone is the same as the total volume of the refined catalyst in the hydrogenation reaction zone and the supplementary refining reaction zone in Example 1.

[0073] In Example 6: The refining catalyst used in the supplementary refining reaction zone is a fluorine-containing refining agent. The active metal elements of the catalyst are Ni, Mo and W. The total content of the active metal components, calculated as oxides, is 27.7 wt%, of which the content of nickel oxide is 2.4 wt%, the content of molybdenum oxide is 2.3 wt%, the content of tungsten oxide is 23.0 wt%, and the content of fluorine is 1.5 wt%.

[0074] As shown in Table 4, the increased degree of ring-opening reaction of cyclic hydrocarbons in Comparative Example 2 resulted in the density of the high-density jet fuel fraction being lower than the technical specifications, thus it could not be considered a qualified product.

[0075] As shown in Table 4, the nitrogen content of the refined effluent in Example 5 decreased and the saturated hydrocarbon content increased, which led to an increase in the naphtha yield in the cracking reaction zone and a decrease in the yield of the high-density jet fuel fraction.

[0076] As shown in Table 4, the ring-opening properties of the reaction products in Example 6 were improved, the naphtha yield increased, and the yield of the high-density jet fuel fraction decreased.

[0077] Table 4

[0078]

[0079]

[0080] Examples 7, 8 and 9

[0081] Examples 7, 8, and 9 used the same raw materials, process flow, and catalyst scheme as Example 1. The feedstock oil was mixed with hydrogen and then sequentially hydrotreated in the reaction zone, hydrocracking reaction zone, and supplementary refining reaction zone, reacting with the catalyst. The reaction effluent was separated and fractionated to obtain naphtha fraction and specialty oil fraction. The corresponding process parameters, product yields, and properties are listed in Table 5. The specific differences are listed below:

[0082] In Example 7: the nitrogen content of the refined oil was 35 μg / g;

[0083] In Example 8: the naphtha fraction at <175℃ yielded 25.5%;

[0084] In Example 9: the hydrocracking catalyst in the hydrocracking reaction zone is CAT-3, and the packing volume is the same as that of CAT-1 in Example 1.

[0085] As shown in Table 5, the reduced denitrification depth in the refining reaction zone in Example 7 led to an increase in the operating temperature of the cracking reaction zone. Consequently, the yield of the product fraction with a temperature <175°C increased, while the yield of the high-density jet fuel fraction decreased slightly.

[0086] As shown in Table 5, the quality of the high-density jet fuel fraction in Example 8 meets the quality index requirements, but the naphtha fraction has a high yield, poor selectivity of the target product, and reduced economic efficiency.

[0087] As can be seen from the results in Table 5, the increased operating temperature of the cracking reaction in Example 9 leads to a shorter catalyst life.

[0088] Table 5

[0089]

[0090] Table 6: Properties of No. 6 High-Specific-Gravity Jet Fuel

[0091]

[0092]

[0093] Table 7: Property Requirements of Low-Temperature Switching Oils (GB 2536-2011)

[0094] project Low-temperature switch oil Pour point / ℃ ≯-60℃ <![CDATA[Density (20°C) / (kg / m 3 )]]> ≯895 Flash point (closed cup) / °C ≮100 <![CDATA[Kinematic viscosity (40°C) / (mm 2 / s)]]> ≯3.5 Sulfur mass fraction / % ≯0.05 Polycyclic aromatic hydrocarbon (PCA) content (mass fraction) / % ≯3.0

[0095] Table 8: Property Requirements for Organic Heat Transfer Fluids (GB 23971-2009)

[0096] project Organic heat transfer fluid Flash point (closed cup) / °C ≮100 Sulfur content (mass fraction) / % ≯0.2 Pour point / ℃ ≯-9℃ <![CDATA[Kinematic viscosity (40°C) / (mm 2 / s)]]> ≯40

[0097] 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 method for producing specialty oils, characterized in that, The method includes: (1) The feed oil and hydrogen-containing gas are introduced into the hydrotreating reaction zone containing hydrorefining catalyst I to carry out the hydrorefining reaction and obtain the refined reaction effluent. (2) The refined reaction effluent is introduced into a hydrocracking reaction zone containing a hydrocracking catalyst to carry out a hydrocracking reaction to obtain a cracking reaction effluent; the hydrocracking catalyst contains a mesoporous molecular sieve, wherein the mesoporous volume ratio of the mesoporous molecular sieve accounts for 15% to 60% of the total pore volume ratio of the mesoporous molecular sieve. (3) The cracking reaction effluent is introduced into a supplementary refining reaction zone containing hydrorefining catalyst II for supplementary refining reaction to obtain supplementary refining reaction effluent; the hydrorefining catalyst II does not contain acidic components; the conditions of the supplementary refining reaction zone are controlled so that the aromatic saturation of the feedstock is 90% to 99%; the aromatic saturation of the feedstock is = 100% × (aromatic content in the feedstock - yield of the >175℃ fraction in the cracking reaction effluent × aromatic content of the >175℃ fraction in the cracking reaction effluent / 100%) / aromatic content in the feedstock; (4) The supplementary refining reaction effluent is separated to obtain naphtha fraction and special oil fraction.

2. The method according to claim 1, characterized in that, The loading volume ratio of the hydrorefining catalyst I and the hydrorefining catalyst II is 5:1 to 2:

1.

3. The method according to claim 1 or 2, characterized in that, The hydrorefining catalyst I and the hydrorefining catalyst II are each independently selected from at least one of the hydrorefining catalysts A; the hydrorefining catalyst A contains a support A and an active metal component supported on the support A, wherein the support A is alumina and / or alumina-silica, and the active metal component contains at least one element selected from Group VIB metals and / or at least one element selected from Group VIII metals.

4. The method according to claim 3, characterized in that, In the hydrorefining catalyst A, the Group VIII metal is selected from nickel and / or cobalt; the Group VIB metal is selected from molybdenum and / or tungsten. Preferably, in the hydrorefining catalyst A, based on the total weight of the hydrorefining catalyst A, the content of the Group VIII metal element, calculated as oxide, is 1 wt% to 15 wt%, and the content of the Group VIB metal element is 5 wt% to 40 wt%.

5. The method according to any one of claims 1-4, characterized in that, Neither the hydrorefining catalyst I nor the hydrorefining catalyst II contains acidic components, which include P and F.

6. The method according to any one of claims 1-5, characterized in that, The conditions in the hydrogenation reaction zone are controlled such that the nitrogen content in the purified reaction effluent is <20 μg / g.

7. The method according to any one of claims 1-6, characterized in that, The reaction conditions in the hydrogenation reaction zone include: a reaction pressure of 10.0 MPa to 16.0 MPa, a reaction temperature of 290°C to 420°C, and a liquid hourly space velocity of 0.3 h⁻¹. -1 ~5h -1 The hydrogen-to-oil volume ratio is 300–2000.

8. The method according to any one of claims 1-7, characterized in that, The hydrocracking catalyst includes a support B and an active metal component supported on the support B, wherein the support B is composed of a heat-resistant inorganic oxide and the mesoporous molecular sieve. Preferably, in the hydrocracking catalyst, the heat-resistant inorganic oxide is selected from at least one of silicon oxide, aluminum oxide, and amorphous aluminum silicate.

9. The method according to claim 8, characterized in that, In the hydrocracking catalyst, the active metal component contains at least two elements selected from Group VIB and Group VIII metals; based on the total weight of the hydrocracking catalyst, the content of the Group VIB metal element is 15wt% to 35wt% and the content of the Group VIII metal element is 2wt% to 8wt% (calculated as oxides).

10. The method according to claim 8 or 9, characterized in that, In the hydrocracking catalyst, based on the total weight of the support B, the content of the mesoporous molecular sieve is 20wt% to 65wt%, with the balance being heat-resistant inorganic oxides.

11. The method according to any one of claims 1-10, characterized in that, In the hydrocracking catalyst, 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 a ZSM-5 molecular sieve.

12. The method according to any one of claims 1-11, characterized in that, The reaction conditions in the hydrocracking reaction zone include: a reaction pressure of 10.0 MPa to 16.0 MPa, a reaction temperature of 290°C to 420°C, and a liquid hourly space velocity of 0.3 h⁻¹. -1 ~5h -1 The hydrogen-to-oil volume ratio is 300–2000.

13. The method according to any one of claims 1-12, characterized in that, The conditions of the hydrocracking reaction zone are controlled such that the conversion rate of the feedstock oil is 8% to 20%; the conversion rate of the feedstock oil = 100% × (mass of naphtha fraction at <175℃ in the cracking effluent / mass of the feedstock oil).

14. The method according to any one of claims 1-13, characterized in that, The reaction conditions in the supplementary purification reaction zone include: a reaction pressure of 10.0 MPa to 16.0 MPa, a reaction temperature of 320°C to 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.

15. The method according to any one of claims 1-14, characterized in that, The feedstock oil has an initial boiling point of D-86 of ≥175℃ and a final boiling point of D-86 of 310-350℃. The total content of cycloalkanes and aromatics in the feedstock oil is ≥80wt%. Preferably, the feedstock oil is selected from at least one of the following: diesel from a catalytic cracking unit, diesel from a fluidized bed hydrocracking unit, coking diesel, and naphthenic crude oil diesel fraction.

Images