Hydraulic oil composition for offshore equipment and preparation method thereof

Abstract

The invention relates to the technical field of hydraulic oil, and discloses a hydraulic oil composition for offshore equipment and a preparation method thereof, the hydraulic oil composition for offshore equipment comprises the following components: main base oil, first auxiliary base oil, second auxiliary base oil, a viscosity index improver and a pour point depressant; the lubricant, the antioxidant, the corrosion inhibitor, the demulsifier and the defoaming agent are added. According to the hydraulic oil composition, a base oil system composed of main base oil and auxiliary base oil is adopted, the overall viscosity of hydraulic oil is reduced, and basic conditions are provided for low-temperature fluidity; through the matching of the lubricant and the viscosity index improver, the specific stable and continuous lubricating performance of the hydraulic oil at different temperatures is ensured; through use of the corrosion inhibitor, the antioxidant, the demulsifying agent, the defoaming agent and other additives, a multi-layer seawater-corrosion-resistant protection system is formed, so that the hydraulic oil composition has the balance of rust prevention, low-temperature and lubricating properties, and shows excellent seawater corrosion resistance and low-temperature flowing property.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic oil, and in particular to a hydraulic oil composition for offshore equipment and a preparation method thereof. Background Art

[0002] Offshore equipment mainly refers to large offshore vessels, ships, offshore wind turbines and offshore platforms. During operation, this type of equipment is subjected to harsh working conditions such as high and low temperatures, seawater immersion and erosion all year round. The hydraulic devices it carries, such as hydraulic cylinders or hydraulic rods, are easily submerged or corroded by seawater, which in turn causes rust on the metal surface, affecting the accuracy and efficiency of the hydraulic system transmission.

[0003] Publication number CN114479991A relates to a hydraulic oil additive composition with salt spray rust prevention properties. This hydraulic oil composition has strong rust prevention properties, but its lubrication properties are poor. In offshore hydraulic equipment, long-term operation of the hydraulic equipment will cause wear of the hydraulic valves and hydraulic rods, thereby affecting the stable operation of the hydraulic equipment, and in severe cases, may cause equipment damage or even production accidents.

[0004] Since offshore equipment is subjected to harsh working conditions such as high and low temperatures, seawater immersion and erosion throughout the year during operation, existing hydraulic oils have problems such as insufficient rust prevention, poor lubrication performance, and poor low-temperature fluidity. It can be seen that the existing technology still needs to be improved and enhanced. Summary of the Invention

[0005] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a hydraulic oil composition for offshore equipment and a preparation method thereof, aiming to provide the hydraulic oil with a balanced performance of rust prevention, low temperature and lubrication through the rational combination of lubricant, base oil and corrosion inhibitor, and exhibit excellent resistance to seawater corrosion and low-temperature fluidity.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A hydraulic oil composition for offshore equipment comprises the following components, calculated by weight: 50-70 parts of a main base oil, 20-30 parts of a first auxiliary base oil, 5-10 parts of a second auxiliary base oil, 5-10 parts of a viscosity index improver, 0.2-0.8 parts of a pour point depressant, 0.4-0.7 parts of a lubricant, 0.08-0.2 parts of an antioxidant, 0.04-0.08 parts of a corrosion inhibitor, 0.01-0.02 parts of an emulsifier, and 0.01-0.02 parts of a defoaming agent.

[0008] The hydraulic oil composition for offshore equipment, wherein the main base oil is 150N, the first auxiliary base oil is 70N, and the second auxiliary base oil is 60N.

[0009] In the hydraulic oil composition for offshore equipment, the viscosity index improver is SCR 178A.

[0010] The hydraulic oil composition for offshore equipment, wherein the pour point depressant is V1-248.

[0011] In the hydraulic oil composition for offshore equipment, the lubricant is composed of 0.4 to 0.6 parts by weight of T323 and 0.03 to 0.05 parts by weight of IR 353.

[0012] In the hydraulic oil composition for offshore equipment, the antioxidant is composed of 0.03 to 0.07 parts by weight of T501 and 0.05 to 0.1 parts by weight of L557.

[0013] In the hydraulic oil composition for offshore equipment, the corrosion inhibitor is composed of 0.02 to 0.05 parts by weight of T561 and 0.02 to 0.03 parts by weight of T106D.

[0014] The hydraulic oil composition for offshore equipment, wherein the demulsifier is T1001.

[0015] The hydraulic oil composition for offshore equipment, wherein the defoaming agent is T921.

[0016] A method for preparing a hydraulic oil composition for offshore equipment comprises the following steps:

[0017] Step S1. Stirring the above parts by weight of the main base oil and the above parts by weight of the first auxiliary base oil and the second auxiliary base oil;

[0018] Step S2. Add the above parts by weight of viscosity index improver, pour point depressant, lubricant and antioxidant to the base oil system and stir until the solution is clear and transparent;

[0019] Step S3. Then, the corrosion inhibitor, defoamer and demulsifier in the above-mentioned parts by weight are added to the solution, and stirred until the solution becomes transparent to obtain the hydraulic oil composition for offshore equipment; wherein, the temperature during the preparation of the hydraulic oil composition for offshore equipment is controlled at 50°C to 55°C.

[0020] Beneficial effects:

[0021] The present invention provides a hydraulic oil composition for offshore equipment and a preparation method thereof. The hydraulic oil composition adopts a base oil system composed of a main base oil and an auxiliary base oil to reduce the overall viscosity of the hydraulic oil, providing a basic condition for low-temperature fluidity. By combining lubricants and viscosity index improvers, the hydraulic oil is ensured to have specific stable and continuous lubrication performance at different temperatures. By using additives such as corrosion inhibitors, antioxidants, demulsifiers, and defoamers, a multi-layered protection system against seawater erosion is formed, so that the hydraulic oil composition has a balanced combination of rust prevention, low-temperature and lubrication properties, and exhibits excellent seawater erosion resistance and low-temperature fluidity. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the copper sheets after corrosion (100°C, 3h) in Examples 1 to 8.

[0023] Figure 2 This is a schematic diagram of the corrosion test using the national standard GB / T 11143.

[0024] Figure 3 Schematic diagram of the extended corrosion experiment. DETAILED DESCRIPTION

[0025] The present invention provides a hydraulic oil composition for offshore equipment and a method for preparing the same. To further clarify the objectives, technical solutions, and advantages of the present invention, the present invention is further described below with reference to the accompanying drawings and examples. It should be understood that the specific examples described herein are intended only to illustrate the present invention and are not intended to limit its scope.

[0026] The present invention provides a hydraulic oil composition for offshore equipment. The hydraulic oil composition comprises the following components, calculated by weight: 50 to 70 parts of a main base oil, 20 to 30 parts of a first auxiliary base oil, 5 to 10 parts of a second auxiliary base oil, 5 to 10 parts of a viscosity index improver, 0.2 to 0.8 parts of a pour point depressant, 0.4 to 0.7 parts of a lubricant, 0.08 to 0.2 parts of an antioxidant, 0.04 to 0.08 parts of a corrosion inhibitor, 0.01 to 0.02 parts of a demulsifier, and 0.01 to 0.02 parts of a defoaming agent.

[0027] Specifically, the main base oil is 150N. 150N base oil is a deeply refined mineral oil, mainly composed of saturated hydrocarbons. After being processed by processes such as hydrorefining, the content of impurities such as sulfur, nitrogen, and oxygen is greatly reduced, and the content of aromatic hydrocarbons is relatively small, which makes the base oil have better antioxidant, corrosion resistance and stability. The higher viscosity provided by 150N base oil enables it to form a thicker and tougher oil film on the metal surface of the hydraulic system. In the hydraulic system of offshore equipment, it will withstand huge loads and pressures during operation. The oil film formed by 150N base oil can effectively separate the metal surface, reduce direct contact and wear, and ensure the smooth operation of the equipment. At the same time, 150N provides a basic stability and viscosity foundation for the entire hydraulic oil system. It cooperates with other auxiliary base oils to jointly adjust the viscosity and performance of the hydraulic oil to adapt to different working conditions.

[0028] Specifically, the first auxiliary base oil is 70N. 70N is also a mineral base oil, but the differences in refining process and raw materials make it different from 150N in terms of component ratio. 70N base oil has good low-temperature performance. The viscosity of 70N is lower than that of 150N. Adding 70N to the system can effectively adjust the overall viscosity of the hydraulic oil. In low-temperature environments, the lower pour point and better low-temperature fluidity can reduce the viscosity of the oil and improve starting performance; in high-temperature environments, it can synergize with the 150N base oil to maintain a certain oil film thickness and ensure lubrication effect. At the same time, 70N is combined with 150N base oil to increase the viscosity index of the hydraulic oil, making the viscosity of the oil change more slowly with temperature, which means that at different operating temperatures, the hydraulic oil can provide stable lubrication performance and reduce performance changes caused by temperature fluctuations.

[0029] Specifically, the second auxiliary base oil is 60N. 60N is a low-viscosity mineral base oil with good low-temperature fluidity, antioxidant and anti-wear properties. The extremely low viscosity of 60N enables it to significantly reduce the viscosity of hydraulic oil at low temperatures, further improve its low-temperature starting performance, and ensure that the oil can maintain good fluidity over a wide temperature range. In addition, it also helps to optimize the volatility of hydraulic oil and reduce the evaporation loss of oil at high temperatures, which is not only conducive to maintaining the stable performance of hydraulic oil, but also reduces the generation of oil mist and improves the safety of the working environment. Furthermore, when in contact with seawater, 60N can optimize the interfacial tension between oil and seawater, reduce the penetration of water and damage to the oil film, and can effectively prevent seawater from contaminating and corroding the oil, thereby extending the service life of the hydraulic oil.

[0030] In this embodiment, the viscosity index improver is SCR 178A, a high molecular weight polymer with the characteristic of regulating viscosity-temperature properties. At high temperatures, its molecular chains stretch, increasing the internal friction of the oil and preventing the viscosity from dropping too much, thereby maintaining a sufficient oil film thickness and ensuring lubrication. At low temperatures, its molecular chains contract, reducing the impact on oil fluidity and lowering viscosity, ensuring that the hydraulic system can start normally at low temperatures. This characteristic allows the hydraulic oil to maintain a stable viscosity over a wide temperature range, adapting to different operating environments and ensuring that the viscosity of the hydraulic oil remains stable at different temperatures. At the same time, SCR 178A can also work synergistically with the base oil system to further optimize the viscosity-temperature properties of the hydraulic oil. SCR 178A can compensate for the shortcomings of the base oil in terms of viscosity-temperature properties, allowing the entire hydraulic oil composition to perform optimally at different temperatures.

[0031] In one embodiment, the pour point depressant is V1-248. The special molecular structure of V1-248 itself enables it to interact with the wax crystals in the base oil and inhibit the growth of wax crystals. Under low temperature conditions, the wax in the base oil will gradually crystallize and precipitate to form a network structure, resulting in poor fluidity of the oil. The pour point depressant can be adsorbed on the surface of the wax crystals to prevent further growth and aggregation of the wax crystals, thereby lowering the pour point of the oil. This allows the hydraulic oil to maintain good fluidity at low temperatures, ensuring that the hydraulic system can start and operate normally in a cold offshore environment. In addition, V1-248 can also synergize with low-viscosity auxiliary base oils (70N and 60N) to further improve the low-temperature performance of the hydraulic oil. The three work together to enable the hydraulic oil to meet the lubrication and operation requirements of the equipment even at extremely low temperatures.

[0032] Specifically, the lubricant comprises 0.4-0.6 parts by weight of T323 and 0.03-0.05 parts by weight of IR353. T323 is a sulfur-phosphorus antiwear agent. The sulfur and phosphorus elements it contains are highly active and can chemically react with metal surfaces. Under high-pressure and high-load operating conditions, T323 can form a strong protective film on the metal surface. This protective film, mainly composed of sulfides and phosphides, can effectively prevent direct contact and wear between metals, reduce the coefficient of friction, and improve the operating efficiency and reliability of the equipment. IR353 contains polar groups that can undergo physical adsorption or chemical reaction with metal surfaces, which assists T323 and further enhances the anti-wear capability of the hydraulic oil. Under low-speed, high-load, or boundary lubrication conditions in hydraulic systems, IR353 can form a physical adsorption film or chemical reaction film on the metal surface, reducing friction and wear between metals and extending the service life of the equipment. It also has certain anti-rust properties and can prevent corrosion of metal parts to a certain extent. Specifically, T323 and IR 353 work together, leveraging their respective strengths under different operating conditions to provide comprehensive lubrication protection. T323 excels under high-pressure, high-speed conditions, while IR 353 is more advantageous under low-speed, boundary lubrication conditions. Together, they ensure excellent lubrication of the hydraulic system under various operating conditions.

[0033] Specifically, the antioxidant is composed of 0.03 to 0.07 parts by weight of T501 and 0.05 to 0.1 parts by weight of L557. T501 is 2,6-di-tert-butyl-p-cresol (BHT), which is a phenolic antioxidant. During use, hydraulic oil will undergo an oxidation reaction with oxygen in the air to produce free radicals. T501 can capture these free radicals and interrupt the chain reaction of the oxidation reaction, thereby delaying the oxidation process of the hydraulic oil. Under high temperature, high pressure and metal catalysis conditions, T501 can maintain stable antioxidant properties, prevent oil oxidation and deterioration, and ensure the stable performance of the hydraulic oil. L557 is an aromatic amine antioxidant, which works synergistically with T501 to further improve the antioxidant properties of the hydraulic oil. L557 can play a role in different oxidation stages, inhibit deep oxidation reactions, and reduce the formation of sludge and acid. L557 and T501 complement each other through different antioxidant mechanisms to form a highly effective antioxidant system, maintaining the cleanliness and stability of the hydraulic oil and extending the service life of the hydraulic oil.

[0034] In this embodiment, the corrosion inhibitor is composed of 0.02-0.05 parts by weight of T561 and 0.02-0.03 parts by weight of T106D. T561 is a benzotriazole (BTA) derivative that can form a stable complex with copper ions. It can form a dense adsorption film on the metal surface, which has a particularly effective protective effect on copper and copper alloys. This film can prevent corrosive media such as oxygen, moisture, and salt from contacting the metal surface, thereby playing an anti-corrosion role, preventing copper alloy parts from corroding and discoloring in hydraulic oil, and ensuring the normal operation of copper components in the hydraulic system. It is particularly suitable for use in offshore environments where the metal parts of the hydraulic system are easily corroded by seawater, moisture, and salt. T106D has good oleophilicity and hydrophobicity, and can form a tight protective film on the metal surface, providing broad-spectrum anti-rust protection for various metal parts (such as steel, aluminum alloy, etc.) in the hydraulic system. T561 and T106D work together to provide comprehensive rust protection for different metal materials. T561 is particularly effective for copper alloys, while T106D has an excellent protective effect on other metals such as steel. Together, they ensure the safe operation of various metal components in the hydraulic system in the corrosive environment of seawater.

[0035] In one embodiment, the demulsifier is T1001. T1001 is a polyether-based demulsifier that can be directionally adsorbed at the oil-water interface. In offshore environments, hydraulic oil easily mixes with seawater, forming an oil-water emulsion. This emulsion can lead to problems such as reduced lubrication performance, increased corrosion, and system pressure fluctuations. T1001 can break the surface tension at the oil-water interface, causing water droplets to coalesce and grow larger, thereby accelerating the separation of water from the oil. This ensures the cleanliness and stable performance of the hydraulic oil and avoids various failures caused by emulsification.

[0036] In this embodiment, the defoaming agent is T921. T921 has extremely low surface tension and can quickly diffuse to the foam surface, causing the foam to break quickly and inhibiting the formation of new foam, thereby ensuring the pressure stability of the hydraulic system and reducing the occurrence of cavitation.

[0037] In the hydraulic oil provided by this invention, the low-viscosity auxiliary base oils (70N and 60N) fundamentally reduce the overall viscosity of the hydraulic oil, providing the foundation for low-temperature fluidity. The pour point depressant (V1-248) further improves the fluidity of the oil at low temperatures by inhibiting the growth of wax crystals. The viscosity index improver (SCR 178A) reduces obstacles to oil fluidity at low temperatures and, acting synergistically with the low-viscosity base oil and pour point depressant, enables the hydraulic oil to flow rapidly in low-temperature environments, meeting the startup and operation requirements of the equipment.

[0038] Corrosion inhibitors (T561 and T106D) form a protective film directly on the metal surface, preventing corrosion from seawater and moisture. Antioxidants (T501 and L557) inhibit oil oxidation, reducing the damage to the inhibitor film caused by oxidation products and prolonging the inhibitor's effective duration. Demulsifier (T1001) promptly separates any seawater that enters the oil, preventing the formation of a stable emulsion between seawater and the oil and reducing the residence time of the corrosive agent in the oil. These agents work together to form a multi-layered anti-seawater corrosion protection system, ensuring the proper operation of the hydraulic system in environments exposed to long-term seawater exposure.

[0039] The primary base oil (150N) provides essential oil film thickness and load-carrying capacity, while lubricants (T323 and IR 353) supplement and enhance lubrication under varying operating conditions. T323 forms a robust protective film under high-pressure, high-speed conditions, while IR 353 provides additional lubrication protection under low-speed, boundary lubrication conditions. The viscosity index improver (SCR 178A) ensures oil film stability at varying temperatures, guaranteeing consistent and stable lubrication performance. The synergistic interaction between these components ensures excellent lubrication of the hydraulic system under various operating conditions, reducing wear and extending equipment life.

[0040] The present invention also provides a method for preparing a hydraulic oil composition for offshore equipment, comprising the following steps:

[0041] Step S1. Evenly mix the aforementioned parts by weight of the primary base oil and the aforementioned parts by weight of the first and second auxiliary base oils. This step allows the base oils of varying viscosities and performance characteristics to be thoroughly mixed, forming a base oil system with specific viscosity and physical properties. The primary base oil provides higher viscosity and load-carrying capacity, while the auxiliary base oils are used to adjust viscosity and improve low-temperature performance. The combined mixture of the three provides a stable and uniform base medium for the subsequent addition of additives.

[0042] Step S2. Add the above-mentioned viscosity index improver, pour point depressant, lubricant, and antioxidant in parts by weight to the base oil system and stir until the solution is clear and transparent. The viscosity index improver can increase the viscosity index of the hydraulic oil, allowing the oil to maintain a stable viscosity at different temperatures; the pour point depressant can lower the pour point of the hydraulic oil and improve its low-temperature fluidity; the lubricant enhances the lubricating properties of the oil and reduces equipment wear; and the antioxidant can inhibit the oxidation reaction of the oil and extend the service life of the hydraulic oil. The above-mentioned additives play an important role in improving the key performance of the hydraulic oil. By stirring, these additives are fully dissolved in the base oil until the solution is clear and transparent, ensuring that the additives are evenly distributed throughout the base oil system, so that the hydraulic oil can exert consistent performance in all parts.

[0043] Step S3. The above-mentioned parts by weight of corrosion inhibitor, defoamer, and demulsifier are then added to the solution, and stirred until the solution becomes transparent, thereby producing the hydraulic oil composition for offshore equipment. The corrosion inhibitor forms a protective film on metal surfaces, preventing corrosion of metal components in the hydraulic system, particularly in high-salt, high-humidity environments at sea, effectively extending the service life of the equipment. The defoamer eliminates foam generated during use, preventing it from affecting the pressure transmission and lubrication performance of the hydraulic system. The demulsifier helps separate water from the hydraulic oil, maintaining the cleanliness and stability of the oil. The addition of the corrosion inhibitor, defoamer, and demulsifier further improves the overall performance of the hydraulic oil.

[0044] The temperature during preparation of the offshore hydraulic oil composition is controlled between 50°C and 55°C. Within this temperature range, the molecular motion of the base oils and additives is more active, accelerating the dissolution of the additives in the base oil and improving mixing efficiency. This also prevents excessively high temperatures from causing additive decomposition or base oil oxidation and deterioration, while also preventing excessively low temperatures from hindering additive dissolution or increasing base oil viscosity, which could affect mixing.

[0045] In order to further illustrate the hydraulic oil composition for offshore equipment and the preparation method thereof provided by the present invention, the following examples are provided:

[0046] The contents of the components in each embodiment are added according to Table 1:

[0047] Table 1 is the content of each component in Example 1-Example 8

[0048]

[0049] The performance test results of each embodiment are shown in Table 2:

[0050] Table 2 is the test results of Examples 1 to 8

[0051]

[0052]

[0053]

[0054]

[0055] From the data in Table 2, we can see that with the help of auxiliary base oil, the hydraulic oil has a lower viscosity and good low-temperature fluidity, which can meet the use requirements of offshore equipment. Through the coordinated use of various additives, the hydraulic oil has good lubrication performance, anti-rust and anti-corrosion performance (liquid phase corrosion test (B method) and copper sheet corrosion (100℃, 3h) in Table 2), level, and Figure 1) etc., to ensure that offshore equipment has excellent resistance to seawater erosion.

[0056] The contents of the components in each comparative example were added according to Table 3:

[0057] Table 3 is the content of each component in Comparative Examples 1 to 8

[0058]

[0059]

[0060] Table 4 is the test results of Comparative Examples 1 to 8

[0061]

[0062]

[0063]

[0064] Commercially available offshore equipment hydraulic oil 1 (Great Wall, H0932) and commercially available offshore equipment hydraulic oil 2 (Flowserve, HV32) were selected for comparative testing as shown in Table 5:

[0065] Table 5 is the performance test results of commercial hydraulic oil

[0066]

[0067]

[0068] Note: Hydraulic oil is washed with water. 300g of oil and 50g of artificial seawater are stirred at 90℃ for 30min. The water layer of the mixture is then discharged with a separatory funnel. The remaining oil layer is used for liquid phase corrosion test. Other requirements are the same as those in GB / T 11143.

[0069] To further evaluate the hydraulic oil's ability to resist seawater corrosion, after completing the national standard GB / T 11143 experiment, we extended the corrosion test to 96 hours. The rusted iron rod was semi-immersed (other conditions were the same as GB / T 11143) to simulate the state of the hydraulic rod when it was extended. The specific experimental conditions are as follows: Figure 2 (National standard rust test method), Figure 3 (Extended corrosion test method) shown.

[0070] The test results are shown in Table 6:

[0071] Table 6 is the test results of extended corrosion test of comparative examples 1-8 and commercial hydraulic oil

[0072]

[0073]

[0074] In Comparative Example 1, the added content of 150N is too little, and the added content of 70N is too much, which makes the overall viscosity of the hydraulic oil low, makes it difficult to form a thicker oil film, and reduces the lubrication performance and anti-wear ability.

[0075] In Comparative Example 2, the added content of 150N is too much, and the added content of 70N is too little. From the data in Table 4, it can be seen that the overall viscosity of Comparative Example 2 is significantly increased, the low-temperature fluidity is poor, and the pour point is increased, which is not conducive to the rapid lubrication of offshore equipment by hydraulic oil in a low-temperature environment and accelerates the wear of the equipment.

[0076] In Comparative Example 3, excessive amounts of 60N were added. The viscosity of the 60N auxiliary base oil is relatively low, and this excessive addition reduced the overall viscosity of the hydraulic oil, excessively lowering the pour point. This made it difficult for the oil to form a sufficiently thick film between moving parts, increasing wear and friction between components. Furthermore, excessive 60N addition caused the oil to easily foam.

[0077] In Comparative Example 4, 60N was omitted and the missing 60N was supplemented with 70N. While this offset the effect on the overall viscosity of the oil caused by the omission of 60N, the viscosity of 70N was higher than that of 60N, resulting in a slight increase in the overall viscosity and increased flow resistance. The low content of the corrosion inhibitor (T106D) weakened the protective film formed on the metal surface, reducing the hydraulic oil's corrosion and oxidation resistance.

[0078] Comparative Example 5 uses a single lubricant (T323). Using only phosphorus-containing T323 as an extreme pressure anti-wear agent, the boundary lubrication ability of the hydraulic oil decreases during the hydraulic system's startup, shutdown, or low-speed operation, increasing wear between metal parts. Furthermore, the anti-corrosion performance decreases to a certain extent.

[0079] Comparative Example 6 uses a single antioxidant (L557). T501 exhibits excellent high-temperature antioxidant properties. While L557 is also an antioxidant, its antioxidant effect in high-temperature environments is not as ideal as the combination of T501 and L557. Using L557 alone can increase the risk of oxidation in hydraulic oil exposed to prolonged high-temperature conditions. This can darken the oil and increase its viscosity, accelerating component corrosion and impacting the performance and service life of the hydraulic oil.

[0080] In Comparative Example 7, the viscosity index improver added in a relatively low amount causes the hydraulic oil's viscosity to change significantly with temperature. At low temperatures, the oil's viscosity is too high, while at high temperatures, it's too low. This prevents the formation of a sufficiently thick oil film between moving parts, resulting in poor lubrication. Furthermore, the viscosity fluctuates with temperature. The low content of the corrosion inhibitor (T106D) reduces the hydraulic oil's corrosion resistance.

[0081] In Comparative Example 8, excessive addition of pour point depressant further lowers the pour point, but it also makes the hydraulic oil too thin at low temperatures, making its viscosity unable to meet the normal operating requirements of the hydraulic system and reducing the low-temperature stability of the oil. It also affects the oil's oxidation stability, generating acidic substances, colloids, and precipitates, which corrode hydraulic system components.

[0082] It is understandable that those skilled in the art can make equivalent substitutions or changes based on the technical solution and inventive concept of the present invention, and all such changes or substitutions should fall within the scope of protection of the present invention.

Claims

1. A hydraulic oil composition for offshore equipment, characterized in that: The components are as follows: main base oil: 50-70 parts, first auxiliary base oil: 20-30 parts, second auxiliary base oil: 5-10 parts, viscosity index improver: 5-10 parts, pour point depressant: 0.2-0.8 parts; Lubricant: 0.4-0.7 parts, antioxidant: 0.08-0.2 parts, corrosion inhibitor: 0.04-0.08 parts, demulsifier: 0.01-0.02 parts, defoaming agent: 0.01-0.02 parts.

2. The hydraulic oil composition for offshore equipment according to claim 1, characterized in that: The main base oil is 150N, the first auxiliary base oil is 70N, and the second auxiliary base oil is 60N.

3. The hydraulic oil composition for offshore equipment according to claim 1, characterized in that: The viscosity index improver is SCR 178A.

4. The hydraulic oil composition for offshore equipment according to claim 1, characterized in that: The pour point depressant is V1-248.

5. The hydraulic oil composition for offshore equipment according to claim 1, characterized in that: The lubricant consists of 0.4 to 0.6 parts by weight of T323 and 0.03 to 0.05 parts by weight of IR 353.

6. The hydraulic oil composition for offshore equipment according to claim 1, characterized in that: The antioxidant consists of 0.03 to 0.07 parts by weight of T501 and 0.05 to 0.1 parts by weight of L557.

7. The hydraulic oil composition for offshore equipment according to claim 1, characterized in that: The corrosion inhibitor consists of 0.02 to 0.05 parts by weight of T561 and 0.02 to 0.03 parts by weight of T106D.

8. The hydraulic oil composition for offshore equipment according to claim 1, characterized in that: The demulsifier is T1001.

9. The hydraulic oil composition for offshore equipment according to claim 1, characterized in that: The defoaming agent is T921.

10. A method for preparing a hydraulic oil composition for offshore equipment, characterized in that: The steps include: Step S1. Stirring the above parts by weight of the main base oil and the above parts by weight of the first auxiliary base oil and the second auxiliary base oil; Step S2. Add the above parts by weight of viscosity index improver, pour point depressant, lubricant and antioxidant to the base oil system and stir until the solution is clear and transparent; Step S3. Then, the corrosion inhibitor, defoamer, and demulsifier in the above-mentioned parts by weight are added to the solution, and the solution is stirred until the solution becomes transparent to obtain the hydraulic oil composition for offshore equipment according to any one of claims 1 to 9; wherein the temperature during the preparation of the hydraulic oil composition for offshore equipment is controlled at 50°C to 55°C.

Images