Preparation method of hydrofined aviation hydraulic oil

Abstract

The invention discloses a preparation method of hydrofined aviation hydraulic oil, which is used for preparing novel aviation hydraulic oil with improved corrosion property and low-temperature property of a copper sheet under the condition that other properties of the aviation hydraulic oil No.15 are basically kept unchanged by adjusting a hydrofining step and a hydrogenation method of base oil. According to a GB / T 5096 test, the copper sheet corrosion of the prepared hydrofined aviation hydraulic oil is not higher than 1b, and according to a GB / T 265 test, the kinematic viscosity at-54 DEG C is not greater than 1150mm < 2 > / s.

Description

Technical Field

[0001] The invention belongs to the field of aviation hydraulic oil, and in particular relates to a method for preparing hydrogenated refined aviation hydraulic oil. Background Art

[0002] The hydraulic oil required by the US MIL-PRF-5606 specification has a base oil that is a refined light diesel fraction. The biggest feature of this hydraulic oil is its good low temperature performance, with a viscosity of no more than 2500mm at -54°C. 2 / s. Therefore, hydraulic oil of MIL-PRF-5606 specification is widely used in automatic control equipment, load gears, shock absorbers, brakes, flap control systems of aircraft hydraulic systems, hydraulic servo systems of missiles, and other hydraulic systems using synthetic sealing materials. However, MIL-PRF-5606 hydraulic oil has a fatal weakness: strong flammability. The flash point of this hydraulic oil is slightly higher than 92℃. It is not only easy to catch fire, but also has a high flame propagation speed. Once the hydraulic system catches fire, it will pose a great threat to the safety of the aircraft and its personnel, which brings serious safety problems to the aircraft. Later, the United States introduced a new MIL-PRF-83282 standard, which is a synthetic hydrocarbon fire-resistant hydraulic oil product. Its fire resistance is better than MIL-PRF-5606 hydraulic oil, but its disadvantage is that its low-temperature performance is relatively poor. Its low-temperature use range is -40℃, which is unacceptable for aviation equipment. Subsequently, the United States introduced a new MIL-PRF-87257 fire-resistant hydraulic oil standard, the full name of which is "Synthetic hydrocarbon-based fire-resistant and low-temperature hydraulic oil for aircraft and missiles." However, the preparation of this standard fire-resistant hydraulic oil remains confidential.

[0003] From the early 1960s to the 1970s, my country successfully developed No. 10 and No. 12 aviation hydraulic oils. No. 10 aviation hydraulic oil is usually made from the 230-305℃ fraction at normal pressure, which is dewaxed by molecular sieves, refined by acid and alkali, refined by white clay, and blended with thickeners, antioxidants and dyes. The flash point of No. 10 aviation hydraulic oil is also slightly higher than 92℃, and its viscosity-temperature performance is good. The operating temperature range is -55-100℃. In order to increase the upper limit of the working temperature, my country subsequently successfully developed No. 12 aviation hydraulic oil and increased the amount of antioxidant added, which improved the thermal stability of the hydraulic oil and the upper limit of the working temperature reached 125℃. In the late 1980s, in order to further increase the upper limit of the operating temperature of hydraulic oil and also to meet the needs of international aviation, my country successfully developed No. 15 aviation hydraulic oil. After comprehensive laboratory evaluation, bench testing and flight trials, it was proved that No. 15 aviation hydraulic oil is superior to No. 10 and No. 12 aviation hydraulic oils in terms of thermal stability, low temperature performance and shear stability, and is equivalent to the US MIL-PRF-5606. However, there is still a certain gap with the current US new MIL-PRF-87257 fire-resistant hydraulic oil standard, especially in terms of copper corrosion performance and low temperature performance. There are obvious deficiencies. With the deterioration of the quality of raw oil products, the above performance indicators have a tendency to further deteriorate, so they still need to be improved. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a method for preparing a hydrofinished aviation hydraulic oil. According to the method for preparing the hydrofinished aviation hydraulic oil of the present invention, by adjusting the hydrofinishing step and hydrogenation method of the base oil, a new aviation hydraulic oil is prepared with improved copper sheet corrosion performance and low temperature performance while keeping other properties of No. 15 aviation hydraulic oil basically unchanged.

[0005] According to a first aspect of the present invention, a first object of the present invention is to provide a method for preparing a hydrofinished aviation hydraulic oil, the method comprising:

[0006] 1) Desalting and dehydrating the base crude oil by ultrasonic desalting.

[0007] 2) The base crude oil treated in step 1) is distilled through a normal vacuum distillation unit to obtain a normal second-line distillate oil with a distillation range of 200-260° C.,

[0008] 3) The fraction obtained in step 2) is subjected to at least two hydrogenation treatments to obtain a hydrorefined base oil, wherein the first hydrogenation reaction temperature is 340°C, the pressure is 7.0 MPa, and the space velocity is 1.5 h -1 , the hydrogen-to-oil volume ratio is 400:1, the reaction temperature of the second hydrogenation is 370°C, the pressure is 5.8MPa, and the space velocity is 2.3h -1 , the volume ratio of hydrogen to oil is 580:1,

[0009] 4) The temperature of the base oil hydrofined in step 3) is controlled to 65° C., and then a tackifier, an antioxidant, an anti-wear agent and an anti-foaming agent are added in proportion, and then stirred for 1-2 hours and filtered;

[0010] 5) Fill the aviation hydraulic oil mixed in step 4).

[0011] Preferably, the base crude oil in step 1) is selected from one or more of Yumen crude oil, Tarim crude oil, and Tuha heavy oil.

[0012] Preferably, the base oil hydrofining treatment step 3) can further be subjected to a third hydrogenation, wherein the reaction temperature of the third hydrogenation is 380°C, the pressure is 7.0 MPa, and the space velocity is 0.6 h -1 , the volume ratio of hydrogen to oil is 580:1.

[0013] Alternatively, step 2) can also be replaced by dewaxing the base crude oil treated in step 1) through a molecular sieve to obtain a molecular sieve dewaxed oil, the feed rate of the dewaxing system used is 2.8-3.5 t / h, and the molecular sieve bed temperature is 250-350°C.

[0014] Preferably, the method may further include step 4') between step 3) and step 4), wherein the hydrorefined base oil obtained in step 3) is further refined with white clay to further remove residual colloids, asphaltene, sulfides, mechanical impurities, etc.

[0015] Preferably, after the first hydrotreating in step 3), the total aromatic content in the conventional second-line distillate oil is reduced from 12.5-18.4% of the raw material to 5.7-8.5%, the content of polycyclic aromatic hydrocarbons (naphthalene, acenaphthene, tricyclic aromatic hydrocarbons) is reduced from 4.8-6.2% of the raw material to 0.2-0.4%, and the sulfur content is less than 1.0 μg / g.

[0016] Preferably, after the second hydrogenation refining in step 3), the total aromatic content is further reduced from 5.7-8.5% in the first hydrogenation to 3.0-3.4%, and the polycyclic aromatic hydrocarbons are substantially completely removed (undetectable amount).

[0017] Preferably, after the third hydrogenation in step 3), the total aromatics are reduced from 3.0-3.4% in the second hydrogenation to 2.4-2.5%.

[0018] Preferably, a dye may also be added in step 4).

[0019] Preferably, a rust inhibitor may also be added in step 4).

[0020] Preferably, in step 4), based on 100 parts by weight of the hydrorefined base oil, 16-20 parts by weight of a tackifier T602, 0.01-2 parts by weight of an antioxidant, 0.01-1.0 parts by weight of an anti-wear agent tricresyl phosphate, and 1-100 ppm of an anti-foaming agent methyl silicone oil are added.

[0021] Preferably, based on 100 parts by weight of the base oil, the antioxidant is added in an amount of 0.1-1.5 parts by weight, more preferably 0.8-1.5 parts by weight.

[0022] Preferably, based on 100 parts by weight of the base oil, the antioxidant is a compound of two antioxidants, the first of which is T501 antioxidant (2,6-di-tert-butyl-p-methylphenol), and the second is selected from T531 antioxidant (N-phenyl-α-naphthylamine) or T534 antioxidant (alkyl diphenylamine). The weight ratio of the first to the second is 10:1 to 1:1, preferably 5:1 to 1:1.

[0023] Preferably, based on 100 parts by weight of the base oil, the anti-wear agent tricresyl phosphate is added in an amount of 0.25-0.75 parts by weight.

[0024] Preferably, based on 100 parts by weight of the base oil, the addition amount of the anti-foaming agent methyl silicone oil is 1-50 ppm, more preferably 5-20 ppm.

[0025] Preferably, the dye is Sudan Red.

[0026] Preferably, based on 100 parts by weight of the base oil, the added amount of the dye is 0.001-0.05 parts by weight, more preferably 0.01-0.02 parts by weight, more preferably 0.01 parts by weight.

[0027] Preferably, the rust inhibitor is Siben 80.

[0028] Preferably, based on 100 parts by weight of the base oil, the amount of the rust inhibitor added is 0.001-0.1 parts by weight, more preferably 0.02-0.1 parts by weight, more preferably 0.05 parts by weight.

[0029] The aviation hydraulic oil prepared according to the method of the present invention has a copper sheet corrosion of no more than 2b according to GB / T 5096 test, and a kinematic viscosity of no more than 1500mm at -54°C according to GB / T 265 test. 2 / s.

[0030] Preferably, the hydrofined aviation hydraulic oil has a copper strip corrosion test of no more than 2a according to GB / T 5096, and a kinematic viscosity of no more than 1370 mm at -54°C according to GB / T 265. 2 / s; More preferably, the hydrofinished aviation hydraulic oil has a copper strip corrosion test of no more than 1b according to GB / T 5096, and a kinematic viscosity of no more than 1150mm at -54°C according to GB / T 265. 2 / s.

[0031] Beneficial Effects

[0032] The preparation method of the hydrorefined aviation hydraulic oil according to the present invention is simple in process by adjusting the hydrorefining steps and hydrogenation method of the base oil, and can especially well overcome the current trend of gradual deterioration of crude oil quality, solve the problem of single source of base oil, expand the source of base oil, and meet the current demand for improvement of my country's No. 15 aviation hydraulic oil. DETAILED DESCRIPTION

[0033] Hereinafter, the present invention will be described in detail. Before describing, it should be understood that the terms used in this specification and the appended claims should not be interpreted as being limited to the general meaning and dictionary meaning, but should be interpreted according to the meaning and concept corresponding to the technical aspects of the present invention on the basis of the principle that the inventor is allowed to appropriately define the terms for the best interpretation. Therefore, the descriptions presented here are only preferred examples for illustrative purposes and are not intended to limit the scope of the present invention, so that it should be understood that other equivalents or improvements can be obtained therefrom without departing from the spirit and scope of the present invention.

[0034] In this document, the terms "include", "including", "have", "contain" or any other similar terms are open conjunctions, which are intended to cover non-exclusive inclusions. For example, a composition or product containing multiple elements is not limited to the elements listed herein, but may also include other elements that are not explicitly listed but are generally inherent to the composition or product. In addition, unless otherwise explicitly stated, the term "or" refers to an inclusive "or" rather than an exclusive "or". For example, any of the following situations satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), and A and B are both true (or exist). In addition, in this document, the interpretation of the terms "include", "including", "have", and "contain" should be considered to have been specifically disclosed and simultaneously cover closed or semi-closed conjunctions such as "consisting of" and "consisting essentially of".

[0035] In this article, all features or conditions defined in the form of numerical ranges or percentage ranges are only for brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be deemed to have covered and specifically disclosed all possible secondary ranges and individual values ​​within the range, especially integer values. For example, the range description of "1 to 8" should be deemed to have specifically disclosed all secondary ranges such as 1 to 7, 2 to 8, 2 to 6, 3 to 6, 4 to 8, 3 to 8, etc., especially secondary ranges defined by all integer values, and should be deemed to have specifically disclosed individual values ​​such as 1, 2, 3, 4, 5, 6, 7, 8, etc. within the range. Unless otherwise specified, the above interpretation method applies to all contents of the entire present invention, regardless of whether the range is broad or not.

[0036] If the quantity or other numerical value or parameter is expressed as a range, a preferred range or a series of upper and lower limits, it should be understood that all ranges consisting of any upper limit or preferred value of the range and the lower limit or preferred value of the range have been specifically disclosed herein, regardless of whether these ranges are disclosed separately. In addition, if a numerical range is mentioned herein, unless otherwise specified, the range should include its endpoints and all integers and fractions within the range.

[0037] In this document, under the premise of achieving the purpose of the invention, numerical values ​​should be understood to have the accuracy of the number of significant digits of the numerical value. For example, the number 40.0 should be understood to cover the range from 39.50 to 40.49.

[0038] Since 2014, the quality of No. 15 aviation hydraulic oil products has gradually become unstable, manifested in the deterioration of copper sheet corrosion performance. This is mainly due to the fact that with the deepening of domestic crude oil mining, the nature of crude oil has become heavier and inferior. The crude oil density has increased from an average of 852.6kg / m 3 Increased to an average of 868.5 kg / m in 2016 3 , the sulfur content increased from 0.18% in 2010 to 0.58% in 2016.

[0039] The main reason for the unqualified corrosion of copper sheets is the sulfur and sulfides in the oil. The main forms of sulfur in crude oil are: mercaptans, sulfides, disulfides, thiophene compounds, etc. Thiophene compounds are sulfides that are difficult to remove in crude oil, and exist in fractions between 60°C and 199°C; benzothiophene and its derivatives are the most difficult sulfides to remove, and exist in the middle fractions greater than 199°C. The current acid-base refining process is difficult to remove benzothiophene sulfides. Although methods of removal using hydrogenation processes have been reported, the current methods are often a treatment method of hydrogenation followed by fractionation, which often causes the acidification of sulfur elements in crude oil and is difficult to remove, resulting in the improvement of copper sheet corrosion performance is still not ideal.

[0040] The present invention adopts a hydrorefining process to replace the traditional acid-base refining process, and in the treatment of the base oil, fine distillation or molecular sieve dewaxing treatment is first adopted, and then at least two hydrogenation treatments are performed, thereby improving the refining depth and completely solving the quality problems caused by the deterioration of crude oil.

[0041] In the method for hydrofining base oil according to the present invention, the conventional second-line distillate oil or molecular sieve dewaxed oil is subjected to at least two hydrogenation treatments, wherein the first hydrogenation reaction temperature is 340°C, the pressure is 7.0 MPa, and the space velocity is 1.5 h -1 , the hydrogen-to-oil volume ratio is 400:1, the reaction temperature of the second hydrogenation is 370°C, the pressure is 5.8MPa, and the space velocity is 2.3h -1 , the volume ratio of hydrogen to oil is 580:1.

[0042] The reaction temperature, air velocity and hydrogen-to-oil volume ratio of the first hydrogenation are all lower (less than) than the second hydrogenation, and the hydrogen pressure of the first hydrogenation needs to be higher than the hydrogen pressure of the second hydrogenation, because the purpose of hydrogenation is to desulfurize, denitrogenate, deoxygenate and solve the problems of oil color and storage stability, reduce the aromatic content, and the organic compound molecules containing sulfur, nitrogen and oxygen undergo hydrogenolysis reaction and impurity removal, and the process of hydrogenation saturation reaction of olefins and aromatic molecules occurs, and the average molecular weight of the processed raw materials and the skeleton structure of hydrocarbon molecules only undergo minimal changes. The reaction temperature, air velocity and hydrogen-to-oil volume ratio of the first hydrogenation are all lower (less than) than the second hydrogenation in order to prevent the skeleton structure of organic hydrocarbon molecules in the feed oil from changing as much as possible, and excessive hydrogenation. But at the same time, in order to maintain the reaction efficiency, appropriately increasing the hydrogen pressure helps to improve the reaction economy, so the hydrogen pressure is maintained at 7.0MPa.

[0043] After the first hydrogenation treatment, most of the organic compound molecules containing sulfur, nitrogen and oxygen have undergone hydrogenolysis reaction, and most of the olefin and aromatic molecules have also undergone hydrogenation saturation reaction, and the content of the remaining unreacted molecules has been greatly reduced. Therefore, in the second hydrogenation process, the reaction temperature, space velocity and hydrogen-to-oil volume ratio are appropriately increased, while the hydrogen pressure is reduced, which is conducive to further reacting the corresponding untreated organic compound molecules containing sulfur, nitrogen and oxygen, olefins and aromatic molecules in the crude oil quickly, while maintaining a low hydrogen pressure to avoid possible decomposition of hydrocarbon molecules caused by excessive hydrogenation.

[0044] Preferably, in order to further thoroughly remove the organic compound molecules containing sulfur, nitrogen and oxygen, a third hydrogenation can be further performed, wherein the reaction temperature of the third hydrogenation is 380°C, the pressure is 7.0 MPa, and the space velocity is 0.6 h -1 The volume ratio of hydrogen to oil is 580:1. This can more effectively remove the above harmful molecules.

[0045] Preferably, after the first hydrotreating in step 3), the total aromatic content in the conventional second-line distillate oil is reduced from 12.5-18.4% of the raw material to 5.7-8.5%, the content of polycyclic aromatic hydrocarbons (naphthalene, acenaphthene, tricyclic aromatic hydrocarbons) is reduced from 4.8-6.2% of the raw material to 0.2-0.4%, and the sulfur content is less than 1.0 μg / g.

[0046] Preferably, after the second hydrogenation refining in step 3), the total aromatic content is further reduced from 5.7-8.5% in the first hydrogenation to 3.0-3.4%, and the polycyclic aromatic hydrocarbons are substantially completely removed (undetectable amount).

[0047] Preferably, after the third hydrogenation in step 3), the total aromatics are reduced from 3.0-3.4% in the second hydrogenation to 2.4-2.5%.

[0048] The following examples are only listed as examples of embodiments of the present invention and do not constitute any limitation to the present invention. It can be understood by those skilled in the art that modifications within the scope of the essence and concept of the present invention fall within the scope of protection of the present invention. Unless otherwise specified, the reagents and instruments used in the following examples are all commercially available products.

[0049] Example 1

[0050] Step 1) 100 kg of Yumen crude oil was subjected to ultrasonic desalting and dehydration for 3 hours;

[0051] Step 2) distilling the base crude oil treated in step 1) through a normal vacuum distillation unit to obtain a normal second-line distillate oil with a distillation range of 200-260° C.;

[0052] Step 3) The fraction obtained in step 2) is subjected to hydrogenation treatment in a fixed bed reactor twice to obtain a hydrorefined base oil, wherein the first hydrogenation reaction temperature is 340°C, the pressure is 7.0 MPa, and the space velocity is 1.5 h -1 , the hydrogen-to-oil volume ratio is 400:1, the reaction temperature of the second hydrogenation is 370°C, the pressure is 5.8MPa, and the space velocity is 2.3h -1 , the volume ratio of hydrogen to oil is 580:1.

[0053] Step 4) The hydrorefined base oil obtained in step 3) is further refined with white clay to further remove residual colloids, asphaltene, sulfides, mechanical impurities, etc.

[0054] Step 5) Based on 100 parts by weight of base oil, 18 parts by weight of tackifier T602 (Mudanjiang Gaoxin Company), 1.1 parts by weight of antioxidant, 0.5 parts by weight of anti-wear agent tricresyl phosphate, 10 ppm of anti-foaming agent methyl silicone oil, 0.05 parts by weight of rust inhibitor Siben 80 and 0.01 parts by weight of Sudan red were weighed.

[0055] The antioxidant is a compound of two antioxidants, T501 and T531, wherein the T501 antioxidant accounts for 0.7 parts by weight and the T531 antioxidant accounts for 0.4 parts by weight.

[0056] Step 6) Heat the hydrorefined base oil obtained in step 4) to 65°C, then add the tackifier T602, antioxidant, anti-wear agent tricresyl phosphate, anti-foaming agent methyl silicone oil and Sudan red in step 5) in sequence, stir for 1-2 hours, and filter.

[0057] Step 7) The hydrorefined aviation hydraulic oil mixed in step 6) is bottled to obtain a final product.

[0058] The base oil indexes after the hydrofining treatment in step 3) are shown in Table 1 below.

[0059] Table 1:

[0060]

[0061] It can be seen that at a reaction temperature of 340°C, a pressure of 7.0 MPa, and a space velocity of 1.5 h -1 , hydrogen-to-oil ratio of 400:1, after one hydrogenation refining, the total aromatic content was reduced from 15.4% of the raw material to 6.9%, the polycyclic aromatic hydrocarbons (naphthalene, acenaphthene, tricyclic aromatic hydrocarbons) content was reduced from 5.2% of the raw material to 0.3%, and the sulfur content was less than 1.0μg / g; at a reaction temperature of 370°C, a pressure of 5.8MPa, and a space velocity of 2.3h -1 After the second hydrogenation of the hydrogenated product under the condition of a hydrogen-to-oil volume ratio of 580:1, the total aromatic content dropped from 6.9% in the first hydrogenation to 3.1%, and all polycyclic aromatics were removed; after the second hydrogenation product was hydrogenated three times, the total aromatics dropped from 3.1% in the second hydrogenation to 2.5%. The main reaction of the hydrogenation process is the saturation of aromatics into cycloalkanes. Since the aromatics in the ordinary second-line oil are mainly one-ring and two-ring, the main reaction of the hydrorefining process is the saturation of one-ring and two-ring aromatics into one-ring and two-ring alkanes; after the third hydrogenation, the structural group composition did not change significantly, indicating that the second hydrogenation has reached the refining depth limit.

[0062] Example 2

[0063] The hydrorefined aviation hydraulic oil was prepared in the same manner as in Example 1, except that in step 2), the base crude oil was dewaxed by molecular sieve to obtain molecular sieve dewaxed oil. The feed rate of the dewaxing system used in the molecular sieve dewaxing treatment was 2.8-3.5 t / h, and the molecular sieve bed temperature was 250-350°C.

[0064] Example 3

[0065] Hydrorefined aviation hydraulic oil was prepared in the same manner as in Example 1, except that in step 1), 100 kg of Yumen crude oil was replaced by 60 kg of Yumen crude oil and 40 kg of Tarim crude oil.

[0066] Comparative Example 1

[0067] Hydrorefined aviation hydraulic oil was prepared in the same manner as in Example 1, except that in step 2), only the first hydrotreatment was performed and the second hydrotreatment was not performed.

[0068] Comparative Example 2

[0069] Hydrofined aviation hydraulic oil was prepared in the same manner as in Example 1 except that the order of preparation steps 2) and 3) was changed, i.e., hydrogenation treatment was first performed and then distillation was performed through a normal vacuum distillation device to obtain a normal second-line distillate oil.

[0070] Test Example 1

[0071] The hydrorefined aviation hydraulic oils of Examples 1 to 3 and Comparative Examples 1 and 2 were tested for kinematic viscosity at different temperatures according to GB / T265, for flash point according to GB / T 3536, for rubber expansion rate according to SH / T 0691, for density according to GB / T1884, for pour point according to GB / T 3535, for evaporation loss according to GB / T 7325, for copper corrosion according to GB / T 5096, and for shear stability according to NB / SH / T0505. The results are listed in Table 2 below.

[0072] Table 2

[0073]

[0074] It can be seen from the data in Table 2 that the hydrofined aviation hydraulic oil prepared according to the present invention is compared with the comparative example 1, which uses only one hydrotreatment, and the comparative example 2, which first hydrotreatment and then distills through the atmospheric and vacuum device to obtain the normal second-line distillate oil. When other performance parameters are basically equal, the copper sheet corrosion level is improved from 2c to 1b, and the corrosion resistance is significantly improved. At the same time, compared with the existing No. 15 hydraulic oil, the performance of various aspects has been improved. Compared with foreign related oil products, other performance parameters are basically equal, but the corrosion resistance and low temperature performance (kinematic viscosity (-54°C)) are also improved.

[0075] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for preparing a hydrorefined aviation hydraulic oil, the method comprising: 1) Desalting and dehydrating the base crude oil by ultrasonic desalting. 2) The base crude oil treated in step 1) is distilled through a normal vacuum distillation unit to obtain a normal second-line distillate oil with a distillation range of 200-260° C., 3) The fraction obtained in step 2) is subjected to at least two hydrogenation treatments to obtain a hydrorefined base oil, wherein the first hydrogenation reaction temperature is 340°C, the pressure is 7.0 MPa, and the space velocity is 1.5 h -1 , the hydrogen-to-oil volume ratio is 400:1, the reaction temperature of the second hydrogenation is 370°C, the pressure is 5.8MPa, and the space velocity is 2.3h -1 , the volume ratio of hydrogen to oil is 580:1, 4) The temperature of the hydrofined base oil in step 3) is controlled to 65°C, and then a tackifier, an antioxidant, an anti-wear agent and an anti-foaming agent are added in proportion, and then stirred for 1-2 hours, filtered, 5) Fill the aviation hydraulic oil mixed in step 4).

2. The method for preparing hydrofinished aviation hydraulic oil according to claim 1, characterized in that: Preferably, the base crude oil in step 1) is selected from one or more of Yumen crude oil, Tarim crude oil, and Tuha heavy oil.

3. The method for preparing hydrofinished aviation hydraulic oil according to claim 1, characterized in that: Preferably, the base oil hydrofining treatment step 3) can further be subjected to a third hydrogenation, wherein the reaction temperature of the third hydrogenation is 380°C, the pressure is 7.0 MPa, and the space velocity is 0.6 h -1 , the volume ratio of hydrogen to oil is 580:

1.

4. The method for preparing hydrofinished aviation hydraulic oil according to claim 1, characterized in that: Alternatively, step 2) can also be replaced by dewaxing the base crude oil treated in step 1) through a molecular sieve to obtain a molecular sieve dewaxed oil, the feed rate of the dewaxing system used is 2.8-3.5 t / h, and the molecular sieve bed temperature is 250-350°C.

5. The method for preparing hydrofinished aviation hydraulic oil according to claim 1, characterized in that: Preferably, the method may further include step 4') between step 3) and step 4), wherein the hydrorefined base oil obtained in step 3) is further refined with white clay to further remove residual colloids, asphaltene, sulfides and mechanical impurities.

6. The method for preparing hydrofinished aviation hydraulic oil according to claim 1, characterized in that: Preferably, after the first hydrofining in step 3), the total aromatic content in the conventional second-line distillate oil is reduced from 12.5-18.4% of the raw material to 5.7-8.5%, the content of polycyclic aromatic hydrocarbons (naphthalene, acenaphthene, tricyclic aromatic hydrocarbons) is reduced from 4.8-6.2% of the raw material to 0.2-0.4%, and the sulfur content is less than 1.0 μg / g; Preferably, after the second hydrogenation refining in step 3), the total aromatic content is further reduced from 5.7-8.5% in the first hydrogenation to 3.0-3.4%, and the polycyclic aromatic hydrocarbons are substantially completely removed (undetectable amount); Preferably, after the third hydrogenation in step 3), the total aromatics are reduced from 3.0-3.4% in the second hydrogenation to 2.4-2.5%; Preferably, a dye is also added in step 4); Preferably, a rust inhibitor is also added in step 4); Preferably, in step 4), based on 100 parts by weight of the hydrorefined base oil, 16-20 parts by weight of the tackifier T602 and 0.01-2 parts by weight of the antioxidant are added. 0.01-1.0 parts by weight of anti-wear agent tricresyl phosphate, and 1-100 ppm of anti-foaming agent methyl silicone oil; Preferably, based on 100 parts by weight of the base oil, the antioxidant is added in an amount of 0.1-1.5 parts by weight, more preferably 0.8-1.5 parts by weight; Preferably, based on 100 parts by weight of the base oil, the antioxidant is a compound of two antioxidants, the first of which is T501 antioxidant (2,6-di-tert-butyl-p-methylphenol), and the second is selected from T531 antioxidant (N-phenyl-α-naphthylamine) or T534 antioxidant (alkyl diphenylamine); the weight ratio of the first to the second is 10:1 to 1:1, preferably 5:1 to 1:1; Preferably, based on 100 parts by weight of the base oil, the anti-wear agent tricresyl phosphate is added in an amount of 0.25-0.75 parts by weight; Preferably, based on 100 parts by weight of the base oil, the amount of the anti-foaming agent methyl silicone oil added is 1-50 ppm, more preferably 5-20 ppm; Preferably, the dye is Sudan red; Preferably, based on 100 parts by weight of the base oil, the amount of the dye added is 0.001-0.05 parts by weight, more preferably 0.01-0.02 parts by weight, more preferably 0.01 parts by weight; Preferably, the rust inhibitor is Siben 80; Preferably, based on 100 parts by weight of the base oil, the amount of the rust inhibitor added is 0.001-0.1 parts by weight, more preferably 0.02-0.1 parts by weight, more preferably 0.05 parts by weight.

7. The method for preparing hydrofinished aviation hydraulic oil according to claim 1, characterized in that: The hydrorefined aviation hydraulic oil prepared by the method has a copper sheet corrosion of no more than 2b according to GB / T 5096 test, and a kinematic viscosity of no more than 1500mm at -54°C according to GB / T 265 test. 2 / s; Preferably, the hydrofinished aviation hydraulic oil prepared by the method has a copper strip corrosion test of no more than 2a according to GB / T 5096, and a kinematic viscosity of no more than 1370 mm at -54°C according to GB / T 265. 2 / s; More preferably, the hydrofinished aviation hydraulic oil has a copper strip corrosion test of no more than 1b according to GB / T 5096, and a kinematic viscosity of no more than 1150mm at -54°C according to GB / T 265. 2 / s.

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