Synthetic carbon dioxide compressor oil and preparation method thereof

Abstract

The invention relates to the technical field of compressor lubricating oil, and particularly discloses synthetic carbon dioxide compressor oil and a preparation method thereof. The synthetic carbon dioxide compressor oil is prepared from the following components in parts by weight: 83.5 to 99.58 parts of polyglycol ether, 0.3 to 8 parts of an antioxidant, 0.1 to 5 parts of an anti-wear reagent at extreme pressure, 0.01 to 3 parts of a corrosion inhibitor and 0.01 to 0.5 part of a de-foaming agent. According to the synthetic carbon dioxide compressor oil disclosed by the invention, the polyglycol ether is adopted as the base oil, and the antioxidant, the extreme pressure anti-wear agent, the corrosion inhibitor and the defoaming agent are added, so that the synthetic carbon dioxide compressor oil has excellent thermal stability and chemical stability, small colloid and carbon residue tendency and excellent rust and corrosion resistance. Importantly, the synthetic carbon dioxide gas compressor oil disclosed by the invention is inert to carbon dioxide gas, and is suitable for multi-stage high-pressure carbon dioxide compressors in the industries of chemical fertilizers, chemistry, food and beverage, gas production and the like.

Description

Technical Field

[0001] This application relates to the technical field of compressor lubricating oil, and more specifically, to a synthetic carbon dioxide compressor oil and a preparation method thereof. Background Art

[0002] With the continuous warming of the global climate, capturing and utilizing CO 2 , 2 , 2 , , 2 , ,

[0005] , ,

[0004] in the air has become one of the effective measures to reduce greenhouse gas pollution. Compared with air, CO 2 has many advantages, such as good thermal performance, high gas flow density, low liquid viscosity, low critical parameters (7.38 MPa, 31.4 °C), easy storage, strong work capacity, good heat transfer performance, and safety and non-toxicity. Therefore, CO2 is widely used in agriculture, food, fire protection, chemical energy, medical treatment, industrial production and other fields.

[0003] A carbon dioxide compressor is a key device for processes such as compressing, transporting and storing CO 2 gas. During the operation of such compressors, compressor lubricating oil is required to lubricate the cylinder, valve and piston rod seal of the compressor to ensure the safe operation of the compressor, extend the oil change cycle, keep the air pressure system clean, reduce friction and transmission energy consumption.

[0004] Regarding the above related technologies, the inventor found that traditional compressor lubricating oils are mostly based on mineral oils. Although they meet the lubrication requirements of compressors within a certain temperature and pressure range, when facing special gas compression, such as carbon dioxide compression, there are some limitations. For example, carbon dioxide may react chemically with the oil during compression, resulting in a decline in the oil performance, such as an increase in gum and carbon residue, corrosion of equipment, etc., thus affecting the normal operation and service life of the compressor. The durable temperature range of traditional lubricating oils is relatively limited. Under high temperature, high pressure and complex working conditions, the solubility of carbon dioxide is relatively high, which not only affects the lubrication performance of the oil, but may also cause the flash point of the oil to decrease, increasing safety risks. In addition, the service life of traditional lubricating oils is also relatively short and needs to be replaced frequently, which not only increases the operating cost, but may also interrupt the production process due to oil replacement, affecting production efficiency.

[0005] Therefore, there is an urgent need for a brand-new synthetic carbon dioxide compressor oil technology that can maintain stable lubrication performance within a wider temperature range and significantly improve the service life of the lubricating oil to meet the requirements of modern industry for high-efficiency, stable and energy-saving equipment. Summary of the Invention

[0006] In order to improve the durable temperature and service life of synthetic carbon dioxide compressor oil, this application provides a synthetic carbon dioxide compressor oil and a preparation method thereof.​​

[0007] In a first aspect, the present application provides a synthetic carbon dioxide compressor oil, adopting the following technical solution: A synthetic carbon dioxide compressor oil, by weight, comprises 83.5 - 99.58 parts of polyethylene glycol ether, 0.3 - 8 parts of antioxidant, 0.1 - 5 parts of extreme pressure and anti-wear agent, 0.01 - 3 parts of corrosion inhibitor, and 0.01 - 0.5 parts of defoamer.

[0008] By adopting the above technical solution, using polyethylene glycol ether as the base oil without the addition of other various auxiliary ester oils, the compressor oil of the present application shows inertness to carbon dioxide. Even under high temperature and high pressure, the solubility of carbon dioxide is very low. Adding antioxidant, extreme pressure and anti-wear agent, corrosion inhibitor and defoamer, it has excellent thermal stability and chemical stability, very little tendency of gum and carbon residue, and at the same time has excellent rust and corrosion prevention properties, and is applicable to multi-stage high-pressure carbon dioxide compressors in industries such as chemical fertilizer, chemistry, food and beverage, and gas production.

[0009] Optionally, by weight, it comprises 90.3 - 96.2 parts of polyethylene glycol ether, 0.8 - 3 parts of antioxidant, 1 - 4 parts of extreme pressure and anti-wear agent, 1.5 - 2.6 parts of corrosion inhibitor, and 0.3 - 0.5 parts of defoamer.

[0010] By adopting the above technical solution, under the raw material formula ratio of the present application, the compressor oil of the present application has low volatility and stable viscosity. Using less additives can make the compressor oil maintain good lubrication performance in a wide temperature range, and maintain excellent chemical inertness, thermal stability, antioxidant property, rust and corrosion prevention properties, etc. under complex and harsh working conditions such as high temperature and high pressure, and extend the service life of the oil.

[0011] Optionally, the polyethylene glycol ether is a linear polymer prepared by ring-opening homopolymerization or copolymerization of propylene oxide, ethylene oxide, and butylene oxide as raw materials under the action of a catalyst, and its technical parameters are as follows: the kinematic viscosity at 40°C is 20 - 500 mm 2 / s, the open flash point ≥ 200°C, the pour point ≤ -27°C, and it is colorless and transparent.

[0012] By adopting the above technical solution, the kinematic viscosity of the polyethylene glycol ether at 40°C is 20 - 500 mm 2 / s, the open flash point ≥ 200°C, the pour point ≤ -27°C. This has a very low solubility in carbon dioxide, can effectively resist the dilution of hydrocarbons, and can maintain stable viscosity characteristics and fluidity within a wide temperature range, ensuring that the carbon dioxide compressor can operate normally in high temperature and low temperature environments.

[0013] Optionally, the corrosion inhibitor is a microcapsule structure with a core material wrapped by a wall material. By weight, the raw materials of the wall material include 7-9 parts of polydimethylsiloxane, 1-1.5 parts of modified nano-silica, and 1.5-2.5 parts of poly(N-isopropylacrylamide), and the raw materials of the core material include 8-12 anti-corrosion active ingredients; the anti-corrosion active ingredients are selected from any one or a combination of benzotriazole, benzotriazole derivatives, and thiadiazole derivatives.

[0014] Optionally, the nano-silica is modified nano-silica, and the preparation method of the modified nano-silica includes the following steps: Disperse the nano-silica in ethanol, ultrasonicate, then add a silane coupling agent, stir at 60-80°C for 3-5 h, and then obtain the product after centrifugal separation, washing, and drying. The concentration of the silane coupling agent is 3-5%.

[0015] Optionally, the silane coupling agent is selected from any one of 3-hydroxypropyltrimethoxysilane or 3-aminopropyltriethoxysilane.

[0016] By adopting the above technical solution, the corrosion inhibitor with a microcapsule structure of a wall material wrapping a core material wraps the anti-corrosion active ingredient as the core material inside, and realizes the gradual release of the anti-corrosion active ingredient on demand during the friction process of the microcapsule, preventing it from decomposing or failing prematurely during storage or use, reducing the waste of the corrosion inhibitor, and effectively prolonging the effective period and service life of the corrosion inhibitor in the compressor oil.

[0017] Polydimethylsiloxane, modified nano-silica, and poly(N-isopropylacrylamide) itself have excellent chemical inertness, thermal stability, and mechanical properties, and are not prone to react with the core material or the external environment, and can provide a stable outer shell protection before the release of the anti-corrosion active ingredient, enhancing the impact resistance and high-temperature resistance of the microcapsule, and preventing the microcapsule from rupturing under high-temperature and high-pressure conditions.

[0018] Poly(N-isopropylacrylamide) has temperature-sensitive properties and can undergo a phase change near a specific temperature. Embedding poly(N-isopropylacrylamide) into the composite wall material of polydimethylsiloxane and modified nano-silica can cause a phase change under high temperature and high pressure, resulting in an increase in the porosity or a loose structure of the microcapsule wall material. This change enables the anti-corrosion active ingredient of the core material to be more easily released from the microcapsule under such complex working conditions.

[0019] After modification of the nano-silica with a silane coupling agent, hygroscopic groups such as amino or hydroxyl groups are introduced on the surface of the modified nano-silica, which makes the modified nano-silica have humidity sensitivity and can expand under high-humidity conditions, further damaging the structure of the microcapsule composite wall material.

[0020] The microcapsule-type corrosion inhibitor of the present application can achieve dual-responsive slow release under high temperature, high pressure and high humidity conditions, ensuring the release of anti-corrosion active ingredients at the required moment, and improving the anti-corrosion performance and service life of oil products.

[0021] Optionally, the antioxidant is any one or a combination of N-phenyl-α-naphthylamine, N-phenyl-β-naphthylamine, octyl butyl diphenylamine, diisooctyl diphenylamine, 2,2,4-trimethyl-1,2-dihydroquinoline polymer, and alkylbenzene α-naphthylamine.

[0022] By adopting the above technical solutions, the antioxidants used in the present application can all significantly improve the antioxidant performance of polyethylene glycol ether base oil. When the flash point of the base oil is about 200 °C, the addition of an appropriate amount of antioxidant can increase the flash point of the oil product to above 260 °C, enabling the synthetic carbon dioxide compressor oil of the present application to have excellent thermal stability and chemical stability under harsh working conditions such as high temperature, high pressure, and long-term operation, and greatly improving the durable temperature and service life of the oil product.

[0023] Optionally, the extreme pressure and anti-wear agent is any one or a combination of zinc dialkyldithiophosphate, dibutyl phosphite, tricresyl phosphate, and triphenyl thiophosphate.

[0024] By adopting the above technical solutions, these extreme pressure and anti-wear agents can enhance the lubrication performance of the engine oil under high load and extreme conditions, protect the equipment from wear, and improve durability.

[0025] Optionally, the defoamer is any one or a combination of non-silicon defoamers, silicone defoamers, polyether defoamers, or polyether-modified silicone defoamers. The defoamers are all in the form of transparent liquids, and the kinematic viscosity at 40 °C is 1-5000 mm 2 / s.

[0026] By adopting the above technical solutions, the generation of foam in the engine oil can be effectively reduced, and the lubrication efficiency of the engine oil and the stability of equipment operation can be improved.

[0027] In a second aspect, the present application provides a preparation method for synthetic carbon dioxide compressor oil, adopting the following technical solutions: A preparation method for synthetic carbon dioxide compressor oil includes the following steps: S1: Add polyethylene glycol ether and an antioxidant to a reaction kettle, stir, seal the lid and evacuate, heat up to 110-130 °C, keep the temperature constant and evacuate to remove water for 1-2 h, and the vacuum degree ≥ -0.08 MPa; S2: After the constant temperature is completed, turn on the cooling water to cool down to 80±5℃, close the vacuum valve, open the kettle cover to add extreme pressure anti-wear agent, corrosion inhibitor and defoaming agent, close the kettle cover, open the filter to circulate for 30-50 minutes, and then filter the material to obtain synthetic carbon dioxide gas compressor oil.

[0028] By adopting the above technical solution and specifying specific preparation process steps and operating conditions, the oil preparation process can be accurately controlled to ensure the stability and consistency of oil quality, and to ensure that all components are fully mixed and perform at their best. During the dehydration process, high temperature and vacuum treatment can significantly reduce the water content in the oil, thereby improving the thermal stability and service life of the oil.

[0029] In summary, this application has the following beneficial effects: 1. This application adopts a kinematic viscosity of 20-500mm at 40°C. 2 / s, open flash point ≥200℃, pour point ≤-27℃ polyglycol ether as base oil is inert to carbon dioxide, can effectively resist dilution by hydrocarbons, and can maintain stable viscosity characteristics over a wide temperature range.

[0030] 2. The synthetic carbon dioxide compressor oil obtained by adding antioxidants, extreme pressure anti-wear agents, corrosion inhibitors and defoaming agents to the base oil in this application has excellent thermal stability and chemical stability, very small tendency of colloid and residual carbon, and excellent anti-rust and anti-corrosion properties. It is suitable for multi-stage high-pressure carbon dioxide compressors in the chemical, fertilizer, food and beverage, gas production and other industries.

[0031] 3. In the present application, a corrosion inhibitor having a microcapsule structure with a composite wall material wrapping a core material having dual responsiveness to temperature and humidity and sustained release is preferred. The anti-corrosion active ingredients are wrapped inside as the core material, and the anti-corrosion active ingredients are gradually released on demand during the friction process of the microcapsule, which effectively extends the validity period and service life of the corrosion inhibitor in the compressor oil, can effectively inhibit the corrosion of compressor parts, and ensure the long-term stable operation of the equipment. DETAILED DESCRIPTION

[0032] The following examples further illustrate the present application in detail.

[0033] raw material Unless otherwise specified, the raw materials used in the examples and comparative examples of this application are all commercially available products, specifically: Polyethylene glycol ether is a linear polymer made from propylene oxide, ethylene oxide, and butylene oxide by ring-opening homopolymerization or copolymerization under the action of a catalyst. Its technical parameters are as follows: Kinematic viscosity at 40°C is 20-500mm 2 / s, open flash point ≥200℃, pour point ≤-27℃, colorless and transparent; Nanosilica, with an average particle size of 200 nm; Polydimethylsiloxane, selected from Nuona Chemistry, CAS: 106214-84-0; Poly(N-isopropylacrylamide), selected from Shanghai Wanna Giant Polymer Technology Co., Ltd., CAS: 25189-55-3; Methylhydrogen silicone oil, selected from Shandong Dayi Chemical Industry, DY-H201, with a hydrogen content of 0.05%; Non-silicon defoamer, selected from Hefei Yueguan New Materials Co., Ltd., DE-0819; Silicone defoamer, selected from Hefei Yueguan New Materials Co., Ltd., DE-0001; Polyether defoamer, selected from Hefei Yueguan New Materials Co., Ltd., DE-1169; Polyether-modified silicone defoamer, selected from Hefei Yueguan New Materials Co., Ltd., DE-0965; The properties of the defoamers used are all transparent liquid type, with a kinematic viscosity of 1-5000 mm 2 / s.

[0034] Preparation Examples of Corrosion Inhibitors Preparation Example 1 The corrosion inhibitor is a microcapsule structure with a core material wrapped by a wall material, and its preparation method includes the following steps: S1: Disperse nanosilica in a 70% ethanol solution, add 3-(trimethoxysilyl)-1-propanol after ultrasonic treatment for 40 min to make the concentration of 3-(trimethoxysilyl)-1-propanol 4%, stir at 70 °C for 4 h, and then perform centrifugal separation, washing and drying to obtain modified nanosilica; S2: Mix 8 parts by weight of polydimethylsiloxane, 1.2 parts by weight of modified nanosilica and 2 parts by weight of poly(N-isopropylacrylamide), and mix with a 70% ethanol solution according to a material-liquid ratio of 1:15, stir evenly to obtain a wall material solution; S3: Mix 10 parts by weight of benzotriazole (T706) with a 70% ethanol solution according to a material-liquid ratio of 1:8, stir evenly, add 1.2 parts by weight of Tween 80, and continue to stir to obtain a core material solution; S4: Add the core material solution to the wall material solution, stir at a speed of 8000 r / min for 15 min, then add 0.8 parts by weight of methylhydrogen silicone oil, and stir evenly for curing; S5: After curing is completed, perform centrifugal separation of the microcapsules, wash with deionized water to remove residual solvents and unreacted raw materials, and obtain the product.

[0035] Preparation Example 2 The corrosion inhibitor is a microcapsule structure with a core material wrapped by a wall material, and its preparation method includes the following steps: S1: Disperse nano-silica in a 70% ethanol solution. After ultrasonic treatment for 40 min, add 3-aminopropyltriethoxysilane so that the concentration of 3-aminopropyltriethoxysilane is 5%. Stir at 80 °C for 5 h, then perform centrifugal separation, washing and drying to obtain modified nano-silica; S2: Mix 9 parts by weight of polydimethylsiloxane, 1.5 parts by weight of modified nano-silica and 2.5 parts by weight of poly(N-isopropylacrylamide), and mix with a 70% ethanol solution according to a material-liquid ratio of 1:16. Stir evenly to obtain a wall material solution; S3: Mix 12 parts by weight of thiazole derivative (T561) with a 70% ethanol solution according to a material-liquid ratio of 1:9. After stirring evenly, add 1.5 parts by weight of Tween 80 and continue stirring to obtain a core material solution; S4: Add the core material solution to the wall material solution, stir at a speed of 8000 r / min for 15 min, then add 1 part by weight of methylhydrogen silicone oil and stir evenly for curing; S5: After curing is completed, perform centrifugal separation of the microcapsules, wash with deionized water to remove residual solvents and unreacted raw materials, and then obtain the product.

[0036] Preparation Example 3 The corrosion inhibitor is a microcapsule structure with a core material wrapped by a wall material, and its preparation method includes the following steps: S1: Disperse nano-silica in a 70% ethanol solution. After ultrasonic treatment for 40 min, add 3-hydroxypropyltrimethoxysilane so that the concentration of 3-hydroxypropyltrimethoxysilane is 3%. Stir at 60 °C for 3 h, then perform centrifugal separation, washing and drying to obtain modified nano-silica; S2: Mix 7 parts by weight of polydimethylsiloxane, 1 part by weight of modified nano-silica and 1.5 parts by weight of poly(N-isopropylacrylamide), and mix with a 70% ethanol solution according to a material-liquid ratio of 1:14. Stir evenly to obtain a wall material solution; S3: Mix 8 parts by weight of benzotriazole derivative (T551) with a 70% ethanol solution according to a material-liquid ratio of 1:7. After stirring evenly, add 1 part by weight of Tween 80 and continue stirring to obtain a core material solution; S4: Add the core material solution to the wall material solution, stir at a speed of 8000 r / min for 15 min, then add 0.5 part by weight of methylhydrogen silicone oil and stir evenly for curing; S5: After curing is completed, perform centrifugal separation of the microcapsules, wash with deionized water to remove residual solvents and unreacted raw materials, and then obtain the product.

[0037] Preparation Example 4 The corrosion inhibitor, different from Preparation Example 1, is that the nano-silica has not undergone the modification treatment in Step S1, and the modified nano-silica in the raw materials is replaced with nano-silica of equal mass, and other steps are the same as those in Preparation Example 1.

[0038] Preparation Example 5 The corrosion inhibitor, different from Preparation Example 1, is that poly(N-isopropylacrylamide) is not added as the raw material for the microcapsule wall material, and other steps are the same as those in Preparation Example 1. Example

[0039] Example 1 A synthetic carbon dioxide compressor oil, the raw materials and their dosages are shown in Table 1, wherein the kinematic viscosity of the polyethylene glycol ether at 40 °C is 400 mm 2 / s, the flash point (open cup) ≥ 200 °C, and the pour point ≤ -27 °C; the antioxidant is N-phenyl-α-naphthylamine (T531); the extreme pressure and anti-wear agent is zinc dialkyldithiophosphate (T202) and dibutyl phosphite (T304) with a mass ratio of 1:1.1; the corrosion inhibitor is obtained from Preparation Example 1; the defoaming agent is a non-silicon type defoaming agent, and the kinematic viscosity at 40 °C is 2000 mm 2 / s.

[0040] Table 1 Component / parts by weight Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Polyethylene glycol ether 83.5 88.6 90.3 92.4 96.2 99.58 Antioxidant 8 3.5 3 1.2 0.8 0.3 Extreme pressure and anti-wear agent 5 4.4 4 3.5 1 0.1 Corrosion inhibitor 3 3 2.3 2.6 1.5 0.01 Defoamer 0.5 0.5 0.4 0.3 0.5 0.01 The preparation method of the above synthetic carbon dioxide compressor oil includes the following steps: S1: Add the polyethylene glycol ether and the antioxidant into the reaction kettle, start stirring, seal the kettle and evacuate, heat up to 110 - 130 °C, keep the temperature constant and evacuate to dehydrate for 1 - 2 h, and the vacuum degree ≥ -0.08 MPa; S2: After the constant temperature ends, turn on the cooling water to cool down to 80 ± 5 °C, close the vacuum valve, open the kettle cover to add the extreme pressure and anti-wear agent, the corrosion inhibitor and the defoaming agent, close the kettle cover, start circulating through the filter for 30 - 50 min, and then filter and discharge to obtain the product.

[0041] Example 2 A synthetic carbon dioxide compressor oil, different from Example 1, is that the raw materials and their dosages are shown in Table 1, wherein the kinematic viscosity of the polyethylene glycol ether at 40 °C is 20 mm 2 / s, the flash point (open cup) ≥ 200 °C, and the pour point ≤ -27 °C; the antioxidant is N-phenyl-β-naphthylamine and octyl butyl diphenylamine (T557) with a mass ratio of 1:1.2; the extreme pressure and anti-wear agent is tricresyl phosphate (T306); the corrosion inhibitor is obtained from Preparation Example 1; the defoaming agent is an organosilicon type defoaming agent, and the kinematic viscosity at 40 °C is 5000 mm 2 / s.

[0042] The preparation method of the above synthetic carbon dioxide compressor oil includes the following steps: S1: Add polyethylene glycol ether and antioxidant into the reaction kettle, start stirring, seal the lid and evacuate the air, heat up to 110 - 130 °C, keep the temperature constant and evacuate water for 1 - 2 h, with the vacuum degree ≥ -0.08 MPa; S2: After the constant temperature ends, turn on the cooling water to cool down to 80 ± 5 °C, close the vacuum valve, open the kettle lid to add extreme pressure anti-wear agent, corrosion inhibitor and defoamer, close the kettle lid, start circulating through the filter for 30 - 50 min, and then discharge through filtration to obtain the product.

[0043] Example 3 A kind of synthetic carbon dioxide compressor oil, the raw materials and their dosages are shown in Table 1, wherein the kinematic viscosity of polyethylene glycol ether at 40 °C is 200 mm 2 / s, the open flash point ≥ 200 °C, and the pour point ≤ -27 °C; the antioxidant is diisooctyl diphenylamine and 2,2,4-trimethyl-1,2-dihydroquinoline polymer (TMQ) with a mass ratio of 1:1.5; the extreme pressure anti-wear agent is triphenyl thiophosphate (T309); the corrosion inhibitor is obtained from Preparation Example 1; the defoamer is a polyether defoamer, and the kinematic viscosity at 40 °C is 1000 mm 2 / s.

[0044] The preparation method of the above synthetic carbon dioxide compressor oil includes the following steps: S1: Add polyethylene glycol ether and antioxidant into the reaction kettle, start stirring, seal the lid and evacuate the air, heat up to 110 - 130 °C, keep the temperature constant and evacuate water for 1 - 2 h, with the vacuum degree ≥ -0.08 MPa; S2: After the constant temperature ends, turn on the cooling water to cool down to 80 ± 5 °C, close the vacuum valve, open the kettle lid to add extreme pressure anti-wear agent, corrosion inhibitor and defoamer, close the kettle lid, start circulating through the filter for 30 - 50 min, and then discharge through filtration to obtain the product.

[0045] Example 4 A kind of synthetic carbon dioxide compressor oil, different from Example 1 in that the raw materials and their dosages are shown in Table 1, wherein the kinematic viscosity of polyethylene glycol ether at 40 °C is 150 mm 2 / s, the open flash point ≥ 200 °C, and the pour point ≤ -27 °C; the antioxidant is alkylbenzene α-naphthylamine; the defoamer is a polyether-modified silicone defoamer, and the kinematic viscosity at 40 °C is 2000 mm 2 / s, and other steps are the same as those in Example 1.

[0046] Example 5 A kind of synthetic carbon dioxide compressor oil, different from Example 1 in that the raw materials and their dosages are shown in Table 1, wherein the kinematic viscosity of polyethylene glycol ether at 40 °C is 100 mm 2 / s, the open flash point ≥ 200 °C, the pour point ≤ -27 °C, and other steps are the same as those in Example 1.

[0047] Example 6 A synthetic carbon dioxide compressor oil, different from Example 1 in that the raw materials and their dosages are shown in Table 1, wherein the kinematic viscosity of polyethylene glycol ether at 40 °C is 500 mm 2 / s, the open flash point ≥ 200 °C, the pour point ≤ -27 °C, and other steps are the same as those in Example 1.

[0048] Example 7 A synthetic carbon dioxide compressor oil, different from Example 4 in that the corrosion inhibitor in the raw materials is obtained from Preparation Example 2, and other steps are the same as those in Example 4.

[0049] Example 8 A synthetic carbon dioxide compressor oil, different from Example 4 in that the corrosion inhibitor in the raw materials is obtained from Preparation Example 3, and other steps are the same as those in Example 4.

[0050] Example 9 A synthetic carbon dioxide compressor oil, different from Example 4 in that the corrosion inhibitor in the raw materials is obtained from Preparation Example 4, and other steps are the same as those in Example 4.

[0051] Example 10 A synthetic carbon dioxide compressor oil, different from Example 4 in that the corrosion inhibitor in the raw materials is obtained from Preparation Example 5, and other steps are the same as those in Example 4.

[0052] Example 11 A synthetic carbon dioxide compressor oil, different from Example 4 in that the corrosion inhibitor in the raw materials is benzotriazole (T706), and other steps are the same as those in Example 4.

[0053] Comparative Example Comparative Example 1 A synthetic carbon dioxide compressor oil, different from Example 4 in that the corrosion inhibitor in the raw materials is replaced with polyethylene glycol ether of equal mass, and the kinematic viscosity of polyethylene glycol ether at 40 °C is 150 mm 2 / s, the open flash point ≥ 200 °C, the pour point ≤ -27 °C, and other steps are the same as those in Example 4.

[0054] Performance Detection Test Perform the following relevant performance detection tests on the synthetic carbon dioxide compressor oils obtained in Examples 1 - 11 and Comparative Example 1. Each test is carried out 3 times, and the average value of the 3 tests is taken as the final result and the final result is recorded in Tables 2 - 3.

[0055] 1. Kinematic viscosity: Refer to GB / T 265 Determination Method for Kinematic Viscosity and Calculation Method for Dynamic Viscosity of Petroleum Products to determine the kinematic viscosity at 40 °C.

[0056] 2. Viscosity index: Refer to GB / T 1995 Calculation Method for Viscosity Index of Petroleum Products to determine the viscosity index.

[0057] 3. Flash point: Refer to GB / T 267 Determination Method for Flash Point of Petroleum Products (Open Cup Method) to determine the open cup flash point.

[0058] 4. Pour point: Refer to GB / T 3535 Determination Method for Pour Point of Petroleum Products to determine the pour point.

[0059] 5. Copper strip corrosion: Refer to SH / T 5095 Determination Method for Copper Strip Corrosion of Lubricating Oil. Immerse a polished copper strip in a certain volume of the test sample. The test temperature is 100 °C and the test time is 24 h. Take out the copper strip, wash it, and compare it with the copper strip corrosion standard color plate to evaluate the color change of the copper strip surface and determine the corrosion level.

[0060] 6. Liquid-phase rust prevention: Refer to ASTM D665 Standard Test Method for Rust Preventive Characteristics of Mineral Oils in the Presence of Water. Mix 300 ml of the test sample with 30 ml of distilled water or synthetic seawater. Immerse the cylindrical test steel rod completely in it and stir at 60 ± 1 °C for 24 h to observe whether the test steel rod rusts.

[0061] 7. Total acid number: Refer to GB / T 7304-2014 Potentiometric Titration Method for the Determination of Acid Number of Petroleum Products to measure the total acid number.

[0062] 8. Oxidation stability: Refer to SH / T 0193-2008 Determination of Oxidation Stability of Lubricating Oil - Rotating Bomb Method. At an experimental temperature of 150 °C and a pressure of 6.21 MPa, accelerate the oxidation reaction of the oil product through a rotating bomb, and measure the time (min) required for the test to reach the specified pressure drop, which is the oxidation induction time.

[0063] 9. Total acid number after oxidation corrosion test: Refer to GB / T 7304-2014 Potentiometric Titration Method for the Determination of Acid Number of Petroleum Products to determine the total acid number of the oil product after oxidation corrosion.

[0064] Table 2 Table 3 From the performance test results of Examples 1-11 and Comparative Example 1 in Tables 2-3, it can be seen that in this application, the kinematic viscosity at 40 °C is 20-500 mm 2 / s, the synthetic carbon dioxide compressor oil prepared with polyethylene glycol ether having an open flash point ≥ 200 °C and a pour point ≤ -27 °C as the base oil has a viscosity index range ≥ 214, a flash point ≥ 295, and a pour point ≤ -38 °C. This shows that the synthetic carbon dioxide compressor oil of the present application can maintain relatively stable viscosity and good fluidity within a wide temperature range, with low volatility, which means that the synthetic carbon dioxide compressor oil of the present application can maintain effective equipment lubrication performance within a wide temperature range, has a lower oil change frequency, a longer service life, and is more durable.

[0065] The 100 °C, 24-hour copper strip corrosion grade of the synthetic carbon dioxide compressor oil of the present application is 1a for all, having liquid-phase corrosion inhibition, with a total acid value range of 0.01 - 0.02 mgKOH / g, and the oxidation stability measured by the rotating oxygen bomb method has a duration of 1440 - 2135 min, and the total acid value range after oxidation corrosion is 0.15 - 0.52 mgKOH / g. This shows that the synthetic carbon dioxide compressor oil of the present application has excellent oxidation stability and anti-rust and anti-corrosion performance, and the oil can maintain long-term effective oxidation stability and corrosion inhibition, further improving the service life and durability of the synthetic carbon dioxide compressor oil of the present application.

[0066] From the performance test results of Examples 1 - 6, it can be seen that under the formulation raw material ratios of Examples 3 - 5, the synthetic carbon dioxide compressor oil has a higher viscosity index, better comprehensive properties such as corrosion resistance and rust resistance, can maintain stable lubrication performance within a wide temperature range, and has a longer service life.

[0067] From the performance test results of Examples 1 - 8 and Example 11, it can be seen that in the present application, a corrosion inhibitor with a microcapsule structure of a composite wall material wrapping a core material having dual temperature and humidity responsive slow release is preferably used, and the anti-corrosion active ingredient is wrapped inside as the core material, and can achieve the gradual release of the anti-corrosion active ingredient on demand during the friction process of the microcapsule. In Example 11, the anti-corrosion active ingredient is directly used as the corrosion inhibitor, and excellent anti-corrosion and anti-rust effects can also be achieved in the initial stage. However, from the perspective of its oxidation stability and the total acid value after oxidation corrosion, the microcapsule-type corrosion inhibitor effectively extends the effective period and service life of the corrosion inhibitor in the compressor oil, thereby improving the durability of the compressor oil, and can effectively inhibit the corrosion of compressor components within a wide temperature range for a long time, ensuring the long-term stable operation of the equipment.

[0068] From the performance test results of Examples 1-8 and Example 9, it can be seen that the microcapsule-type corrosion inhibitor prepared by embedding temperature-sensitive poly(N-isopropylacrylamide) into the composite wall material of polydimethylsiloxane and modified nano-silica has a stronger ability to protect the equipment and devices of compressor oil against oxidation and rust, and a longer service life. This is because the microcapsule-type corrosion inhibitor can cause a phase change under high temperature and pressure, resulting in an increase in the porosity or a loosening of the structure of the microcapsule wall material. This change enables the effective anti-corrosion components of the core material to be more easily released from the microcapsules under such complex working conditions, achieving an effective corrosion inhibition effect.

[0069] From the performance test results of Examples 1-8 and Example 10, it can be seen that the microcapsule-type corrosion inhibitor prepared by using the modified nano-silica obtained by modifying nano-silica with a silane coupling agent as a raw material for the composite wall material has a stronger ability to protect the equipment and devices of compressor oil against oxidation and rust, and a longer service life. This is because hygroscopic groups such as amino or hydroxyl groups are introduced on the surface of the modified nano-silica, which makes the modified nano-silica humidity-sensitive and can expand according to humidity response even under low-temperature conditions, resulting in the destruction of the structure of the microcapsule composite wall material, enabling the effective anti-corrosion components of the core material to be more easily released from the microcapsules under such complex working conditions, achieving an effective corrosion inhibition effect.

[0070] This specific embodiment is only an interpretation of the present application and does not limit the present application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A synthetic carbon dioxide compressor oil, characterized in that: According to weight parts, it comprises 83.5-99.58 parts of polyethylene glycol ether, 0.3-8 parts of antioxidant, 0.1-5 parts of extreme pressure anti-wear agent, 0.01-3 parts of corrosion inhibitor and 0.01-0.5 parts of defoaming agent.

2. The synthetic carbon dioxide compressor oil according to claim 1, characterized in that Calculated by weight, the composition comprises 90.3-96.2 parts of polyethylene glycol ether, 0.8-3 parts of antioxidant, 1-4 parts of extreme pressure anti-wear agent, 1.5-2.6 parts of corrosion inhibitor and 0.3-0.5 parts of defoaming agent.

3. The synthetic carbon dioxide compressor oil according to claim 1, characterized in that The polyglycol ether is a linear polymer obtained by homopolymerization or copolymerization of propylene oxide, ethylene oxide and butylene oxide as raw materials under the action of a catalyst. Its technical parameters are as follows: Kinematic viscosity at 40°C is 20-500mm 2 / s, open flash point ≥200℃, pour point ≤-27℃, colorless and transparent.

4. The synthetic carbon dioxide compressor oil according to claim 1, characterized in that The corrosion inhibitor is a microcapsule structure in which a core material is wrapped by a wall material. In terms of weight, the raw materials of the wall material include 7-9 parts of polydimethylsiloxane, 1-1.5 parts of modified nano-silicon dioxide and 1.5-2.5 parts of poly N-isopropylacrylamide, and the raw materials of the core material include 8-12 parts of anti-corrosion effective ingredients; the anti-corrosion effective ingredients are selected from any one or more combinations of benzotriazole, benzotriazole derivatives and thiadiazole derivatives.

5. The synthetic carbon dioxide compressor oil according to claim 4, characterized in that The preparation method of the modified nano silicon dioxide comprises the following steps: The nano-silicon dioxide is dispersed in ethanol, ultrasonicated, and then a silane coupling agent is added, stirred at 60-80° C. for 3-5 hours, and then centrifuged, washed and dried to obtain the product, wherein the concentration of the silane coupling agent is 3-5%.

6. The synthetic carbon dioxide compressor oil according to claim 5, characterized in that The silane coupling agent is selected from any one of 3-hydroxypropyltrimethoxysilane and 3-aminopropyltriethoxysilane.

7. The synthetic carbon dioxide compressor oil according to claim 1, characterized in that The antioxidant is any one or more combinations of N-phenyl-α-naphthylamine, N-phenyl-β-naphthylamine, octylbutyldiphenylamine, diisooctyldiphenylamine, 2,2,4-trimethyl-1,2-dihydroquinoline polymer and alkylbenzene α-naphthylamine.

8. The synthetic carbon dioxide compressor oil according to claim 1, characterized in that The extreme pressure anti-wear agent is any one or more combinations of dialkyl zinc dithiophosphate, dibutyl phosphite, tricresyl phosphate and triphenyl thiophosphate.

9. The synthetic carbon dioxide compressor oil according to claim 1, characterized in that The defoamer is any one or more combinations of a non-silicon defoamer, an organosilicon defoamer, a polyether defoamer or a polyether-modified organosilicon defoamer. The defoamer is a transparent liquid with a kinematic viscosity of 1-5000 mm at 40°C. 2 / s.

10. The method for preparing a synthetic carbon dioxide compressor oil according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1: Add polyethylene glycol ether and antioxidant into the reaction kettle and stir, cover and evacuate, raise the temperature to 110-130° C., and evacuate and dehydrate at a constant temperature for 1-2 hours, with a vacuum degree of ≥-0.08 MPa; S2: After the constant temperature is completed, turn on the cooling water to cool down to 80±5℃, close the vacuum valve, open the kettle cover to add extreme pressure anti-wear agent, corrosion inhibitor and defoaming agent, close the kettle cover, open the filter to circulate for 30-50 minutes, and then filter the material to obtain synthetic carbon dioxide gas compressor oil.

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