High-temperature heat pump working medium composition and application thereof

Abstract

The invention discloses a high-temperature heat pump working medium composition and application thereof.The high-temperature heat pump working medium composition comprises a lubricating oil composition and a high-temperature heat pump working medium, the lubricating oil composition comprises base oil, and the base oil is mainly composed of medium-chain and long-chain fatty acid ester. Furthermore, the lubricating oil composition further comprises an additive, and the additive comprises at least one of an antioxidant and a free acid capturing agent; in the lubricating oil composition, the mass percentage content of the additive is 0.1-5 wt%. The lubricating oil composition disclosed by the invention has excellent compatibility, viscosity-temperature capacity, chemical stability and oxidation resistance when being used for a high-temperature heat pump working medium; furthermore, decomposition of HFO can be slowed down, and the acid value of the HFOs type high-temperature heat pump working medium is effectively inhibited from rising.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-temperature heat pump oil products, and in particular, relates to a high-temperature heat pump working fluid composition, a preparation method and an application thereof. Background Art

[0002] A large amount of industrial energy consumption is directly discharged in various forms of waste heat, and this wasted energy can be used as a heat source in the same industrial site. High-temperature heat pumps are energy-saving devices that elevate low-level heat sources to high-level heat sources. They can effectively recycle industrial waste heat to produce high-temperature heat sources, thereby improving industrial energy utilization and reducing carbon emissions. According to the Kigali Amendment to the Montreal Protocol and the 2024 Hydrofluorocarbon Quota Setting and Allocation Plan, R245fa, a commonly used HFC substance in the field of high-temperature heat pumps, will face strict reductions and usage restrictions due to its high GWP.

[0003] HFOs high-temperature heat pump fluids are expected to replace R245fa in the field of high-temperature heat pumps. The patent application with application number CN111378417A discloses the use of HFOs environmentally friendly fluid HP-1 to replace R245fa. In order to promote the actual application of HFOs in high-temperature heat pumps, it is necessary to develop a high-temperature heat pump lubricant suitable for HFOs high-temperature heat pump fluids.

[0004] The exhaust temperature of a high-temperature heat pump is much higher than that of traditional heat pumps such as household air conditioners and commercial air conditioners. The lubricating oil of a high-temperature heat pump is in a high-temperature, high-pressure working environment in the compressor for a long time. The working conditions of the two are very different. To ensure the long-term and reliable operation of the compressor, the viscosity-temperature capability, oxidation resistance and chemical stability of the lubricating oil of a high-temperature heat pump are very important. At present, the lubricating oil used in compressors is more focused on the low-temperature field. The high-temperature miscibility and high-temperature stability of common commercially available lubricating oils and high-temperature heat pump working fluids are not ideal, so it is difficult to adapt to high-temperature heat pump working fluids. Therefore, it is urgent to develop a high-temperature heat pump lubricating oil with excellent viscosity-temperature capability, good high-temperature compatibility, excellent oxidation resistance and chemical stability suitable for HFOs high-temperature heat pump working fluids. Summary of the invention

[0005] In order to solve the higher requirements on the viscosity-temperature capability, high-temperature compatibility, oxidation resistance and chemical stability of lubricating oil due to the high-temperature and high-pressure working environment of high-temperature heat pump working fluids (specifically HFOs-type high-temperature heat pump working fluids), the present invention uses a composition mainly composed of medium- and long-chain fatty acid esters as a lubricating oil base oil for use with high-temperature heat pump working fluids, which meets the requirements of high-temperature heat pump working fluids for viscosity-temperature performance and has excellent solubility, chemical stability and oxidation resistance.

[0006] Specifically, the present invention provides the following technical solutions:

[0007] The present invention provides a high-temperature heat pump working fluid composition, which comprises a lubricating oil composition and a high-temperature heat pump working fluid. The lubricating oil composition comprises a base oil, and the base oil is mainly composed of medium- and long-chain fatty acid esters.

[0008] According to an embodiment of the present invention, the high-temperature heat pump working fluid is HFOs-type high-temperature heat pump working fluid.

[0009] According to an embodiment of the present invention, the lubricating oil composition further comprises an additive, and the additive comprises an antioxidant.

[0010] According to an embodiment of the present invention, the additive may further include at least one of the following substances: a free acid scavenger, a metal deactivator, an antifoaming agent, an extreme pressure antiwear agent, and a friction modifier.

[0011] According to an embodiment of the present invention, in the lubricating oil composition, the mass percentage of the additive is 0.1 to 5 wt %.

[0012] According to an embodiment of the present invention, in the mixture of the high-temperature heat pump working fluid (specifically, HFOs-based high-temperature heat pump working fluid) and the above-mentioned base oil, the content of the base oil can be added arbitrarily as needed. For example, the content of the base oil (by weight) can be 1% to 99%, for example, 10% to 90%, and for example, 5% to 60%.

[0013] According to an embodiment of the present invention, the weight ratio of the lubricating oil composition to the high-temperature heat pump working fluid (specifically, HFOs high-temperature heat pump working fluid) is 5:95 to 50:50.

[0014] According to an embodiment of the present invention, the two-phase separation temperature of the lubricating oil composition and the high-temperature heat pump working fluid (specifically, HFOs high-temperature heat pump working fluid) in the high-temperature section between a weight ratio of 5:95 and 50:50 is not lower than 150°C, and there is at least one point in the low-temperature section where the two-phase separation temperature is not higher than -70°C, that is, the lubricating oil composition and the high-temperature heat pump working fluid (specifically, HFOs high-temperature heat pump working fluid) are completely miscible in the high-temperature section and miscible in the low-temperature section.

[0015] According to an embodiment of the present invention, the HFOs high temperature heat pump working fluid is composed of component (a) or a mixture of component (a) and component (b), wherein:

[0016] Component (a) is at least one selected from the group consisting of HFO-1234yf, HFO-1234ze(E), HFO-1233zd(E), HFO-1234zb(Z), HFO-1243zf, HFO-1336mmz(Z) and HFO-1336mmz(E);

[0017] Component (b) is at least one selected from HFC refrigerants.

[0018] According to an embodiment of the present invention, the medium-chain fatty acid ester is an ester of a medium-chain fatty acid and an alcohol reactant.

[0019] According to an embodiment of the present invention, the alcohol reactant is, for example, a polyol. For example, the carbon number of the polyol is 4 to 15, more preferably 4 to 12, and most preferably 4 to 10. For example, the polyol includes, but is not limited to, at least one of pentaerythritol, dipentaerythritol, neopentyl glycol, trimethylolpropane, and polymethylolethane.

[0020] In one embodiment of the present invention, the carbon number of the polyol is 4 to 6. For example, the polyol is pentaerythritol. When the carbon number of the polyol is 4 to 6, the base oil composed of the medium-chain fatty acid ester is a low-viscosity base oil.

[0021] In one embodiment of the present invention, the carbon number of the polyol is 8 to 11. For example, the polyol is dipentaerythritol. When the carbon number of the polyol is 8 to 11, the base oil composed of the medium-chain fatty acid ester is a high-viscosity base oil.

[0022] According to an embodiment of the present invention, the medium-chain fatty acid can be either a monoacid or a diacid; it can be either normal or isomeric.

[0023] In one embodiment of the present invention, the carbon number of the medium-chain fatty acid is 7 to 18, preferably 7 to 12, and more preferably 8 to 10. For example, the medium-chain fatty acid includes, but is not limited to, at least one of caprylic acid, nonanoic acid, capric acid, lauric acid, palmitic acid, stearic acid, arachidic acid, isodecanoic acid, isolauric acid, isopalmitic acid, isostearic acid, isooctanoic acid, isononanoic acid, azelaic acid, linoleic acid, linolenic acid, dodecanedioic acid, neodecanoic acid, 2-ethylheptanoic acid and isononanoic acid. Preferably, it is a mixture of the above two acids, such as a mixture of isononanoic acid and isooctanoic acid, and the mixing weight ratio of the two is (50 to 60): (40 to 50) (total 100 parts by mass), such as 55:45.

[0024] According to an embodiment of the present invention, the kinematic viscosity of the low viscosity base oil at 40°C is 30 to 100 mm 2 / s, preferably 40 to 80 mm 2 / s, preferably 40-70mm 2 / s; the kinematic viscosity of high viscosity base oil at 40°C is 150-300 mm 2 / s, preferably 170-260mm 2 / s, preferably 190~240mm 2 / s.

[0025] According to an embodiment of the present invention, the kinematic viscosity of the low viscosity base oil at 100°C is 4 to 11 mm 2 / s, preferably 5-10mm 2 / s; the kinematic viscosity of the high viscosity base oil at 100 ° C is 15 to 21 mm 2 / s, preferably 17-19mm 2 / s.

[0026] According to an embodiment of the present invention, the flash point (opening) of the low viscosity base oil is not less than 200°C, preferably not less than 220°C; the flash point (opening) of the high viscosity base oil is not less than 250°C, preferably not less than 280°C.

[0027] According to an embodiment of the present invention, the pour point of the low viscosity base oil is not higher than -30°C, preferably not higher than -36°C; the pour point of the high viscosity base oil is not higher than -21°C, preferably not higher than -24°C.

[0028] According to an embodiment of the present invention, the mass content of the additive is preferably 0.5 to 3 wt%.

[0029] In one embodiment of the present invention, in the additive, the antioxidant accounts for 40 to 60 wt % of the total amount of the additive.

[0030] In one embodiment of the present invention, the free acid scavenger accounts for 30-40 wt % of the total amount of the additive.

[0031] In one embodiment of the present invention, the metal deactivator content does not exceed 30 wt % of the total amount of the additive.

[0032] According to an embodiment of the present invention, the additives include an antioxidant, a free acid scavenger and a metal deactivator.

[0033] In one embodiment of the present invention, the antioxidant accounts for 40-60wt% of the total amount of the additive, the free acid scavenger accounts for 30-40wt% of the total amount of the additive, and the metal deactivator content does not exceed 30wt% of the total amount of the additive.

[0034] According to an embodiment of the present invention, the antioxidant is at least one of a phenolic antioxidant and an amine antioxidant, preferably a phenolic antioxidant or a mixture of a phenolic antioxidant and an amine antioxidant.

[0035] According to an embodiment of the present invention, the phenolic antioxidant includes but is not limited to at least one of hydroquinone, 2,6-di-tert-butyl-4-methylphenol, AO-2246, nonylphenol, 2,4,6-tri(tert-butyl)phenol, butylated trans-4-hydroxyphenylpropionate, 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 4,4'-thiobis(3-methyl-6-tert-butylphenol), tris(2,4-di-tert-butylphenyl) phosphite, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, tris(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, and the like.

[0036] According to an embodiment of the present invention, the amine antioxidant includes but is not limited to at least one of diphenylamine, alkylated diphenylamine, N-phenyl-α-naphthylamine, N,N'-diisopropyl-p-phenylenediamine, N,N'-diphenyl-p-phenylenediamine, 4,4'-di-tert-butyldiphenylamine, etc.

[0037] According to an embodiment of the present invention, the free acid capture agent includes but is not limited to at least one of zinc stearate, aluminum stearate, magnesium stearate, calcium stearate, propylene oxide, ethylene oxide, epoxidized soybean oil, glycidyl methacrylate, octyl glycidyl ether, benzylamine, isopropanolamine, pentaerythritol tetrastearate, magnesium hydroxide, calcium hydroxide, zinc hydroxide, basic zinc carbonate, basic magnesium carbonate, calcium borate phenolate, etc.

[0038] According to an embodiment of the present invention, the metal deactivator, anti-foaming agent, anti-emulsifier, extreme pressure anti-wear agent and friction modifier can be selected from substances known in the art; exemplarily, the metal deactivator is, for example, benzotriazole, N,N'-di(2-ethylhexyl)-methyl-1H-benzotriazole-1-methylamine, benzotriazole derivatives, thiadiazole derivatives; exemplarily, the anti-foaming agent is, for example, methyl silicone oil, acrylate copolymer; exemplarily, the extreme pressure anti-wear agent is, for example, sulfided isobutylene, dibenzyl disulfide, aminothioester, di-n-butyl phosphite, tricresyl phosphate, isooctyl acid phosphate octadecylamine salt, triphenyl thiophosphate, butyl isooctyl phosphate dodecylamine salt, thiophosphate triester, dialkyl dithiophosphate; exemplarily, the friction modifier is, for example, oleic acid, stearic acid, dodecanol, hexadecanol, oleyl alcohol, butyl oleate, butyl stearate, hexadecylamine, oleic acid amide, benzotriazole derivatives.

[0039] According to an embodiment of the present invention, the lubricating oil composition has at least one of the following properties:

[0040] (1) The lubricating oil composition including the low-viscosity base oil has a kinematic viscosity of 30 to 100 mm at 40°C. 2 / s, preferably 40 to 80 mm2 / s, preferably 40-70mm 2 / s; The kinematic viscosity of the lubricating oil composition comprising the high viscosity base oil at 40 ° C is 150 to 300 mm 2 / s, preferably 170-260mm 2 / s, preferably 190~240mm 2 / s.

[0041] (2) The kinematic viscosity of the lubricating oil composition including the low-viscosity base oil at 100° C. is 4 to 11 mm 2 / s, preferably 5-10mm 2 / s; The kinematic viscosity of the lubricating oil composition including the high viscosity base oil at 100 ° C is 15 to 21 mm 2 / s, preferably 17-19mm 2 / s.

[0042] (3) The hydroxyl value is not more than 5 mgKOH / g, preferably not more than 3 mgKOH / g, and more preferably not more than 2 mgKOH / g.

[0043] (4) The flash point (opening point) of the lubricating oil composition including the low-viscosity base oil is not lower than 200°C, preferably not lower than 220°C.

[0044] (5) The flash point (opening point) of the lubricating oil composition including the high-viscosity base oil is not lower than 250°C, preferably not lower than 280°C.

[0045] (6) The pour point of the lubricating oil composition including the low-viscosity base oil is not higher than -30°C, preferably not higher than -36°C.

[0046] (7) The pour point of the lubricating oil composition including the high-viscosity base oil is not higher than -20°C, preferably not higher than -25°C.

[0047] According to an embodiment of the present invention, the lubricating oil composition is prepared by a method comprising the following steps: reacting an alcohol reactant with a medium-chain fatty acid to obtain the base oil.

[0048] According to an embodiment of the present invention, the method further comprises the following step: mixing the base oil with an additive to obtain the lubricating oil composition.

[0049] According to an embodiment of the present invention, the alcohol reactant has the above definition.

[0050] According to an embodiment of the present invention, the medium-chain fatty acid has the definition as above.

[0051] According to an embodiment of the present invention, the reaction molar ratio of the alcohol reactant to the medium-chain fatty acid is calculated based on the molar ratio of the hydroxyl group of the alcohol reactant to the carboxyl group of the medium-chain fatty acid, and the molar ratio of the hydroxyl group of the alcohol reactant to the carboxyl group of the medium-chain fatty acid is 1:1.1 to 1:1.2. Exemplarily, the molar ratio of the hydroxyl group of the alcohol reactant to the carboxyl group of the medium-chain fatty acid is 1:1.1, 1:1.12, 1:1.14, 1:1.16, 1:1.18 or 1:1.2.

[0052] According to an embodiment of the present invention, the reaction temperature is 200° C. to 280° C. Specifically, if the reaction is carried out in the presence of a catalyst, the reaction temperature may be 200° C. to 260° C.; if no catalyst is added during the reaction, the reaction temperature is 240° C. to 280° C.; exemplary temperatures are 200° C., 230° C., 240° C., 250° C., and 260° C.

[0053] According to an embodiment of the present invention, the reaction time is 6 h to 24 h, preferably 6 h to 12 h, and exemplified by 6 h, 8 h, 10 h, 12 h, 15 h, 20 h, and 24 h.

[0054] According to an embodiment of the present invention, the reaction can be carried out in the presence of a catalyst. Preferably, the catalyst can be at least one of an inorganic acid, an organic acid, a solid acid, a metal and a metal compound. For example, the catalyst is selected from at least one of p-toluenesulfonic acid, tributyl phosphate, sodium bisulfate, phosphotungstic acid and silicon-supported phosphotungstic acid. The addition of a catalyst can reduce the temperature of the reaction of polyols with medium and long chain fatty acids and shorten the reaction time.

[0055] According to an embodiment of the present invention, the base oil and additive are mixed by introducing an inert gas at a temperature above 30° C. (preferably 50-150° C., such as 80° C.) for mixing and stirring. Preferably, the inert gas is a substance known in the art, such as nitrogen.

[0056] According to an embodiment of the present invention, when mixed, the mass content of the additive is 0.1 to 5 wt % of the lubricating oil composition.

[0057] The present invention also provides application of the high-temperature heat pump working fluid composition in a high-temperature heat pump.

[0058] The present invention also provides a high-temperature heat pump, which comprises the high-temperature heat pump working fluid composition.

[0059] Beneficial effects of the present invention:

[0060] The present invention provides a base oil including medium-chain fatty acid esters, the base oil having significantly excellent high-temperature chemical stability and the ability to be compatible with high-temperature heat pump working fluids at high temperatures. Specifically, the present invention uses medium-chain fatty acid esters synthesized from alcohol reactants (such as pentaerythritol and dipentaerythritol) and medium-chain fatty acids as high-temperature heat pump lubricant base oils to ensure the viscosity-temperature capability of high-temperature heat pump lubricant base oils. At the same time, the base oil of the present invention has excellent compatibility with HFOs-type high-temperature heat pump working fluids, and the two have excellent chemical stability when mixed and used. In addition, the present invention puts forward requirements for the hydroxyl value of the high-temperature heat pump working fluid composition to ensure that it still has excellent high-temperature chemical stability with HFOs-type high-temperature heat pump working fluids under high-temperature working conditions. In short, the lubricating oil composition of the present invention has excellent compatibility, viscosity-temperature capability, chemical stability and oxidation resistance with high-temperature heat pump working fluids (specifically such as HFOs-type high-temperature heat pump working fluids).

[0061] Furthermore, the present invention, through the combination of the base oil and the additive, can not only have the above-mentioned excellent compatibility, viscosity-temperature capability, chemical stability and oxidation resistance, but also slow down the decomposition of HFO and effectively inhibit the increase of the acid value of HFOs-type high-temperature heat pump working fluids. DETAILED DESCRIPTION

[0062] The technical scheme of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary descriptions and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0063] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0064] The test methods involved in the following embodiments and comparative examples of the present invention are as follows:

[0065] Density at 25℃, viscosity at 40℃: GB / T 29617-2013;

[0066] Flash point (open): GB / T 267-1988;

[0067] Pour point: GB / T 3535-2006;

[0068] Compatibility with refrigerants: SH / T 0699-2000;

[0069] Chemical stability: SH / T 0698-2000;

[0070] Chroma: SH / T 0168-1992;

[0071] Fluorine content: GB / T 40111-2021;

[0072] Acid value: GB / T 7304-2014.

[0073] Pentaerythritol (purchased from Anhui Jinhe Industrial Co., Ltd.); dipentaerythritol (Shanghai Maclean Biochemical Technology Co., Ltd.); isononanoic acid (Shanghai Maclean Biochemical Technology Co., Ltd.); 2-ethylhexanoic acid (Shanghai Maclean Biochemical Technology Co., Ltd.); 2,6-di-tert-butyl-4-methylphenol (Shanghai Maclean Biochemical Technology Co., Ltd.); AO-2246 (Shanghai Maclean Biochemical Technology Co., Ltd.); glycidyl methacrylate (Shanghai Maclean Biochemical Technology Co., Ltd.); isopropanolamine (Shanghai Maclean Biochemical Technology Co., Ltd.); benzotriazole derivatives (Jinzhou Shengda Chemical Co., Ltd.).

[0074] Example 1

[0075] The lubricating oil base oil is composed of medium-chain fatty acid esters obtained by reacting dipentaerythritol with two acids. The medium-chain fatty acid esters contain 55% isononanoate structure and 45% isooctanoate structure by weight percentage.

[0076] The preparation method of lubricating base oil comprises the following steps: 100 g of dipentaerythritol, 225.9 g of isononanoic acid and 168.4 g of isooctanoic acid are weighed and poured into a reaction kettle, and then 4.9 g of p-toluenesulfonic acid is added, and nitrogen is introduced for 5 minutes, and then heated to 200°C and reacted for 8 hours. After the reaction is completed, the reaction is cooled to room temperature, and the lubricating base oil is obtained through post-treatment processes such as alkali washing and water washing, which is a high-viscosity lubricating oil.

[0077] Example 2

[0078] Except that 80.31 g of pentaerythritol was used to replace the dipentaerythritol in Example 1, the other steps were the same as in Example 1 to obtain a lubricating oil base oil, which was a low-viscosity base oil.

[0079] Comparative Example 1

[0080] Commercially available lubricating oil RENISO SE 220 (purchased from FUCHS, Germany).

[0081] Comparative Example 2

[0082] The unreacted lubricating oil base oil is composed of the following components in percentage by weight: 55% of isononanoate and 45% of isooctanoate.

[0083] Preparation method of incompletely reacted lubricating oil base oil: Weigh 100 g of dipentaerythritol, 225.9 g of isononanoic acid, and 168.4 g of isooctanoic acid respectively and pour them into a reaction kettle. After introducing nitrogen for 5 minutes, heat to 200 °C and react for 8 hours. After the reaction is completed, cool to room temperature, and obtain the incompletely reacted lubricating oil base oil through post-treatment processes such as alkali washing and water washing.

[0084] Comparative Example 3

[0085] Lubricating oil base oil, composed of medium and long-chain fatty acid esters. The medium and long-chain fatty acid esters are medium and long-chain fatty acid esters of dipentaerythritol and two acids. In the medium and long-chain fatty acid esters, by weight percentage: the isononanoate structure is 80%, and the isooctanoate structure is 20%.

[0086] Preparation method of lubricating oil base oil: Weigh 100 g of dipentaerythritol, 268.8 g of isononanoic acid, and 91.5 g of isooctanoic acid respectively and pour them into a reaction kettle. Then add 4.6 g of p-toluenesulfonic acid. After introducing nitrogen for 5 minutes, heat to 200 °C and react for 8 hours. After the reaction is completed, cool to room temperature, and obtain the base oil through post-treatment processes such as alkali washing and water washing.

[0087] 1. Physicochemical property analysis

[0088] Measure the chromaticity, density at 25 °C, viscosity at 40 °C, viscosity at 100 °C, flash point, and pour point of the lubricating oil base oil of the examples and comparative examples. The results are shown in Table 1 below.

[0089] Table 1 Physicochemical properties

[0090] performance Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Chromaticity (ASTM number) 0.5 0.5 0.5 0.5 0.5 <![CDATA[Density at 25℃ / (g / cm 3 )]]> 0.9651 0.9543 0.9724 0.9758 0.9654 <![CDATA[Viscosity at 40°C / (mm 2 / s)]]> 234.8 67.4 220.7 323.0 275.0 <![CDATA[Viscosity at 100℃ / (mm 2 / s)]]> 18.9 8.7 19.0 19.6 21.0 Flash point (open) / ℃ 298 246 294 250 304 Pour point / ℃ -27 -33 -27 -9 -18

[0091] As can be seen from Table 1, for the lubricating oil base oil with medium and long-chain fatty acid esters obtained by reacting dipentaerythritol with medium and long-chain fatty acids as the active ingredient in the present invention, all physicochemical properties can achieve the same effect as commercially available lubricating oils. However, when there is incompletely reacted dipentaerythritol, it will have a great impact on the performance of the lubricating oil; in addition, when the weight percentage of isononanoate and isooctanoate in the lubricating oil base oil exceeds (50 - 60):(40 - 50), it will cause the pour point of the lubricating oil base oil to rise, thus greatly affecting the low-temperature performance of the lubricating oil base oil and further restricting its low-temperature storage conditions.

[0092] In addition, for the low-viscosity lubricating oil base oil obtained by reacting pentaerythritol with medium and long-chain fatty acids in the present invention, all physicochemical properties also meet the performance requirements of the lubricating oil base oil in this field.

[0093] 2. Compatibility test with HFOs-based high-temperature heat pump working fluids at different oil contents

[0094] The lubricating base oil obtained in the above examples and comparative examples was mixed with HFOs-based high-temperature heat pump working fluid, and the compatibility of the lubricating base oil and the HFOs-based high-temperature heat pump working fluid at different oil contents was measured. The results are shown in Tables 2 and 3 below.

[0095] Wherein: the HFOs high temperature heat pump working fluid is composed of the following components in molar percentage: HFO-1336mzz (E) 25% and HFO-1234ze (Z) 75%.

[0096] Table 2 High temperature (20℃~150℃) compatibility test results (℃)

[0097]

[0098] Table 3 Low temperature (-70℃~20℃) compatibility test results (℃)

[0099]

[0100] As can be seen from Tables 2 and 3, the lubricating base oil of the present invention, which uses the medium-chain fatty acid ester obtained by the reaction of dipentaerythritol and medium-chain fatty acids as the active ingredient, is miscible with HFOs-type high-temperature heat pump working fluids at different oil contents, both in the high-temperature section and the low-temperature section, and compared with the conventional commercially available lubricating base oil, the lubricating base oil of the present invention has better low-temperature compatibility under high oil content conditions. When the lubricating base oil contains unreacted dipentaerythritol and / or changes the weight percentage of isononanoic acid ester and isooctanoic acid ester, the low-temperature compatibility between the lubricating base oil and the heat pump working fluid will be affected, thereby greatly increasing the risk of precipitation of the lubricating base oil in the heat exchanger, thereby reducing the heat exchange efficiency of the heat exchanger. In summary, the lubricating base oil of the present invention is fully compatible with HFOs-type high-temperature heat pump working fluids in terms of performance, and can meet various usage scenarios of HFOs-type high-temperature heat pump working fluids.

[0101] In addition, the low-viscosity lubricating oil base oil obtained by reacting pentaerythritol and medium- and long-chain fatty acids in the present invention is compatible with HFOs-type high-temperature heat pump working fluids at different oil contents in both high-temperature and low-temperature sections.

[0102] 3. Chemical stability test

[0103] The lubricating oil base oils of the examples and comparative examples were mixed with HFOs high-temperature heat pump working fluids and subjected to chemical stability tests. The mixtures were heated at 175° C. for 14 days. The results are shown in Table 4.

[0104] Wherein: the HFOs high temperature heat pump working fluid is composed of the following components in molar percentage: HFO-1336mzz (E) 25% and HFO-1234ze (Z) 75%.

[0105] Table 4 Chemical stability test

[0106]

[0107] As shown in Table 4, after 14 days of chemical stability test, the chromaticity of the high temperature heat pump lubricating oil base oil of Examples 1-2 of the present invention did not change, and the acid value and fluorine content were lower than those of Comparative Examples 1 and 2. This shows that the medium-chain fatty acid esters obtained by reacting pentaerythritol, dipentaerythritol and medium-chain fatty acids as the active ingredient of the lubricating oil base oil can effectively slow down the decomposition of HFO to produce fluorine-containing acidic substances such as trifluoroacetic acid, and slow down metal corrosion.

[0108] In summary, the present invention can slow down the decomposition of HFO components in HFOs high-temperature heat pump working fluids to produce trifluoroacetic acid by controlling the composition and weight percentage of the long-chain fatty acid ester active ingredients in the high-temperature heat pump lubricant base oil. The high-temperature heat pump lubricant base oil of the present invention has excellent viscosity-temperature capability and excellent compatibility with HFOs high-temperature heat pump working fluids. The high-temperature two-phase separation temperature of any ratio is greater than 150°C; and when the oil content is 60%, the low-temperature two-phase separation temperature of the lubricant base oil of the present invention and the HFOs high-temperature heat pump working fluid is still less than -70°C.

[0109] Preparation Example 1

[0110] The lubricating oil base oil is composed of the following components in percentage by weight: 45% of isononanoate and 55% of isooctanoate.

[0111] The preparation method of lubricating base oil comprises the following steps: 100 g of dipentaerythritol, 184.8 g of isononanoic acid and 205.9 g of isooctanoic acid are weighed and poured into a reactor, and 4.9 g of p-toluenesulfonic acid is added, and nitrogen is introduced for 5 minutes, and then heated to 200°C and reacted for 8 hours. After the reaction is completed, the reaction is cooled to room temperature, and the lubricating base oil is obtained through post-treatment processes such as alkali washing and water washing, which is a high-viscosity base oil.

[0112] Preparation Example 2

[0113] Commercially available lubricating oil RENISO SE 220 (purchased from FUCHS, Germany).

[0114] Preparation Example 3

[0115] The same procedures as in Preparation Example 1 were followed except that 80.31 g of pentaerythritol was used to replace the dipentaerythritol in Preparation Example 1, to obtain a lubricating oil base oil, which was a low-viscosity base oil.

[0116] Examples 3-9 and Comparative Examples 4-6

[0117] The preparation process of the high temperature heat pump lubricating oil composition is as follows:

[0118] With reference to the compositions of the embodiments and comparative examples in Table 5, corresponding raw materials were prepared (each component was expressed in mass percentage), and nitrogen was introduced at 80° C. and mixed and stirred for 20 minutes to obtain a high-temperature heat pump lubricating oil composition.

[0119] Table 5 Raw material composition of embodiments and comparative examples

[0120]

[0121] Test Example 1 Basic Physical and Chemical Performance Analysis

[0122] The high-temperature heat pump lubricating oil compositions of Examples 3-9 and Comparative Examples 4-6 were respectively taken, and their basic physical and chemical properties were tested according to the above test methods, and the results were compiled in Table 6.

[0123] Table 6 Basic physical and chemical properties

[0124]

[0125] It can be seen from Table 6 that the addition of 0.1-5 wt% of additives to the high-temperature heat pump lubricating oil composition does not affect the basic physical and chemical properties of the high-temperature heat pump lubricating oil; however, when the amount of the additive exceeds 5 wt%, the viscosity of the high-temperature heat pump lubricating oil composition will be significantly reduced.

[0126] Test Example 2

[0127] Compatibility test with HFOs high temperature heat pump working fluid at different oil contents:

[0128] 1. Take the high-temperature heat pump lubricating oil compositions of Examples 3 to 9 and Comparative Examples 4 to 6 respectively, and mix them with HFOs mixed high-temperature heat pump working fluid to prepare different high-temperature heat pump working fluids, wherein the mass fraction (i.e., oil content) of the high-temperature heat pump lubricating oil composition is 5%, 10%, 20%, 40%, and 50%, respectively. The HFOs high-temperature heat pump working fluid is composed of the following molar percentage components: HFO-1336mzz(Z) 25% and HFO-1234ze(Z) 75%.

[0129] 2. The above-mentioned high-temperature heat pump working fluid was subjected to low-temperature compatibility test and high-temperature compatibility test. The test method was SH / T 0699-2000 mentioned above. The test results are shown in Table 7, wherein the oil content refers to the mass fraction of the high-temperature heat pump lubricating oil composition in the sum of the high-temperature heat pump lubricating oil composition and the high-temperature heat pump working fluid.

[0130] Table 7 High temperature (20℃~150℃) compatibility test results (℃)

[0131]

[0132] Table 8 Low temperature (20℃~-70℃) compatibility test results (℃)

[0133]

[0134] It can be seen from Tables 7 and 8 that under different oil usage ratios, the high-temperature heat pump lubricating oil composition of the present invention and the HFOs mixed high-temperature heat pump working fluid are miscible between -70°C and 150°C, which shows that the present invention does not affect the compatibility of the high-temperature heat pump lubricating oil composition and the HFOs mixed high-temperature heat pump working fluid by adding 0.1 to 5wt% of additives to the high-temperature heat pump lubricating oil composition. When the amount of additive added exceeds 5wt%, the compatibility of the high-temperature heat pump lubricating oil composition and the high-temperature heat pump working fluid will be seriously affected. The high-temperature heat pump lubricating oil composition of the present invention is fully compatible with the HFOs mixed high-temperature heat pump working fluid, and can meet various usage scenarios of this type of high-temperature heat pump working fluid.

[0135] Test Example 3 Chemical Stability Test

[0136] The high-temperature heat pump lubricating oil compositions of Examples 3 to 9 and Comparative Examples 4 to 6 were subjected to the following chemical stability test: referring to the test method of SH / T 0698-2000, heating at 175° C. for 14 days; the test results are shown in Table 9.

[0137] Wherein: the HFOs high temperature heat pump working fluid is composed of the following components in molar percentage: HFO-1336mzz (E) 25% and HFO-1234ze (Z) 75%.

[0138] Table 9 Chemical stability test As shown in Table 9, after 14 days of chemical stability test, the high temperature heat pump working fluid mixture added with the high temperature heat pump lubricating oil composition of Examples 3 to 6 has no significant change in chromaticity, and the acid value and fluorine content are lower than those of the high temperature heat pump working fluid added with the composition of Comparative Example 2, indicating that the present invention can effectively slow down the decomposition of HFO to produce fluorine-containing acidic substances such as TFA by using the medium-chain fatty acid ester obtained by reacting pentaerythritol, dipentaerythritol and medium-chain fatty acids as the active ingredient of the base oil; compared with Comparative Example 4, it can be seen that the addition of 0.1 to 5wt% of additives to the high temperature heat pump lubricating oil composition of the present invention does not affect the ability of the medium-chain fatty acid ester to slow down the decomposition of HFOs high temperature heat pump working fluid. When the amount of additive added exceeds 5wt%, although the acid value of the high temperature heat pump working fluid mixture will not be significantly increased, it will cause severe discoloration and there is a certain risk of metal corrosion. Examples 7 to 9 illustrate that the present invention can reduce the acid value of the lubricating oil during the aging process to inhibit the occurrence of metal corrosion by adding a free acid scavenger to the high-temperature heat pump lubricating oil composition; antioxidants and benzotriazole derivatives can inhibit the self-oxidation reaction of the oil during the aging process, improve the quality of the oil, reduce the degree of discoloration of the oil, and avoid the formation of sludge or varnish.

[0139] Test Example 4 Antioxidant Test

[0140] The high-temperature heat pump lubricating oil compositions of Examples 3 to 9 and Comparative Examples 4 to 6 were subjected to the following antioxidant induction test: referring to the test method of ASTM D7545, the initial pressure of pure oxygen was 700 kPa, and the time required for a pressure drop of 10% was measured at 160°C. The test results are shown in Table 10.

[0141] Table 10 Antioxidant Test

[0142] Test oil Induced oxidation time / min Oil color change Precipitate Example 3 981.9 No change none Example 4 1201.5 No change none Example 5 812.4 No change none Example 6 996.1 No change none Comparative Example 4 67.1 deepen none Comparative Example 5 874.3 No change none Comparative Example 6 282.1 deepen none Example 7 949.7 No change none Example 8 649.2 No change none Example 9 1348.3 No change none

[0143] As shown in Table 10, the present invention can effectively prolong the anti-oxidation time of the lubricant by adding 0.1-5wt% of the additive to the high-temperature heat pump lubricant composition, while when the amount of the additive added exceeds 5wt%, the improvement of the anti-oxidation performance of the additive will be reduced. The present invention can effectively prolong the anti-oxidation time of the lubricant by adding an antioxidant, a free acid scavenger and a benzotriazole derivative to the high-temperature heat pump lubricant composition through the synergistic effect of the components.

[0144] In summary, the present invention successfully provides a medium- and long-chain fatty acid ester high-temperature heat pump lubricant composition suitable for HFOs high-temperature heat pump working fluid. The physical and chemical properties of the composition meet the relevant national standards, and the low-temperature and high-temperature compatibility with HFO mixed high-temperature heat pump working fluid is excellent, and it can be miscible with HFOs high-temperature heat pump working fluid between -70°C and 150°C.

[0145] The above is a description of the exemplary embodiments of the present invention. However, the protection scope of the present application is not limited to the above embodiments. Any modification, equivalent substitution, improvement, etc. made by those skilled in the art within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-temperature heat pump working fluid composition, characterized in that: The high-temperature heat pump working fluid composition comprises a lubricating oil composition and a high-temperature heat pump working fluid. The lubricating oil composition comprises a base oil, and the base oil is mainly composed of medium- and long-chain fatty acid esters.

2. The high-temperature heat pump working fluid composition according to claim 1, characterized in that: The high-temperature heat pump working fluid is HFOs type high-temperature heat pump working fluid.

3. The high-temperature heat pump working fluid composition according to claim 1 or 2, characterized in that: The lubricating oil composition further comprises an additive, wherein the additive comprises an antioxidant; Preferably, the additive further comprises at least one of the following substances: a free acid scavenger, a metal deactivator, an antifoaming agent, an extreme pressure antiwear agent, and a friction modifier; In the lubricating oil composition, the mass percentage of the additive is 0.1-5wt%.

4. The high-temperature heat pump working fluid composition according to any one of claims 1 to 3, characterized in that: The weight ratio of the lubricating oil composition to the high-temperature heat pump working fluid is 5:95 to 50:

50.

5. The high-temperature heat pump working fluid composition according to any one of claims 1 to 4, characterized in that: The medium-chain fatty acid ester is an esterification product of a medium-chain fatty acid and an alcohol reactant; and / or, the alcohol reactant is a polyol; and / or, the carbon number of the medium-chain fatty acid is 7 to 18; And / or, the additives include antioxidants, free acid scavengers and metal deactivators; And / or, in the additive, the antioxidant accounts for 40-60wt% of the total amount of the additive; And / or, in the additive, the free acid scavenger accounts for 30-40wt% of the total amount of the additive; And / or, in the additive, the content of the metal deactivator does not exceed 30wt% of the total amount of the additive.

6. The high-temperature heat pump working fluid composition according to any one of claims 1 to 5, characterized in that: The antioxidant is at least one of a phenolic antioxidant and an amine antioxidant; And / or, the free acid scavenger includes at least one of zinc stearate, aluminum stearate, magnesium stearate, calcium stearate, propylene oxide, ethylene oxide, epoxidized soybean oil, glycidyl methacrylate, octyl glycidyl ether, benzylamine, isopropanolamine, pentaerythritol tetrastearate, magnesium hydroxide, calcium hydroxide, zinc hydroxide, basic zinc carbonate, basic magnesium carbonate, and calcium borate phenolate; and / or, the metal deactivator is at least one of benzotriazole, N,N'-di(2-ethylhexyl)-methyl-1H-benzotriazole-1-methylamine, benzotriazole derivatives, and thiadiazole derivatives; And / or, the anti-foaming agent is at least one of methyl silicone oil and acrylate copolymer; And / or, the extreme pressure anti-wear agent is at least one of sulfided isobutylene, dibenzyl disulfide, aminothioester, di-n-butyl phosphite, tricresyl phosphate, isooctyl acid phosphate octadecylamine salt, triphenyl thiophosphate, butyl isooctyl phosphate dodecylamine salt, thiophosphate triester, and dialkyl dithiophosphate; And / or, the friction modifier is at least one of oleic acid, stearic acid, dodecanol, hexadecanol, oleyl alcohol, butyl oleate, butyl stearate, hexadecylamine, oleic acid amide, and benzotriazole derivatives.

7. The high-temperature heat pump working fluid composition according to any one of claims 1 to 6, characterized in that: The lubricating oil composition is prepared by a method comprising the following steps: reacting an alcohol reactant with a medium-chain fatty acid to obtain the base oil.

8. The high-temperature heat pump working fluid composition according to claim 7, characterized in that: The method further comprises the following steps: mixing the base oil with an additive to obtain the lubricating oil composition.

9. Use of the high-temperature heat pump working fluid composition according to any one of claims 1 to 8 in a high-temperature heat pump.

10. A high-temperature heat pump, comprising the high-temperature heat pump working fluid composition according to any one of claims 1 to 8.

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