KR20070055352A - Lube base oil and refrigeration oil containing the same - Google Patents

Abstract

The present invention relates to a refrigerator using a hydrocarbon-based refrigerant, more specifically a refrigerator oil for a compressed refrigerator using a hydrocarbon having 2 to 4 carbon atoms as a refrigerant and a lubricating base oil used therein. The lubricant base oil has a viscosity at 40 ° C. of 5-20 mm 2 / s, (ii) viscosity index of 90 or more, (i) aniline point of 90 or more, (i) pour point of -35 ° C. or less, (iv) aromatic 0.1 wt% or less of component, (i) sulfur component and nitrogen component of 1 ppm or less, and (iii) 20% effluent temperature in simulated distillation according to ASTM D 2887 is 300 ℃ or more, 50% effluent temperature Is 350 ° C. or higher and 90% outlet temperature is 400 ° C. or higher. The refrigeration oil composed of the lubricant base oil and various additives exhibits excellent durability and wear resistance.

Refrigerator oil, hydrocarbon refrigerant, R600a

Description

Lube base oil and refrigeration oil containing the same {Lube Base Oil and Refrigeration Oil Containing the Same}

1 is a view showing a schematic configuration of a test refrigeration system manufactured to evaluate the durability of the refrigeration oil, according to an embodiment of the present invention.

The present invention relates to a lubricant base oil suitable for refrigeration oil for a refrigerator using a hydrocarbon-based refrigerant. More specifically, the present invention relates to a lubricating base oil suitable for the production of compressed refrigeration oil using a hydrocarbon having 2 to 4 carbon atoms as a refrigerant.

Chlorofluorocarbons (CFC), such as trichlorofluoromethane (R-11), dichlorodifluoromethane (R-12), and chlorodifluoromethane (R-22), which are conventionally used as refrigerants in compressed refrigerators. , And hydrochlorofluorocarbons (HCFCs) are toxic, non-explosive and stable and have been used in refrigerators, air conditioners and the like from the 1930s to the 1990s. However, CFCs are very stable substances that, when released into the air, do not decompose well in the atmosphere, but gradually move to the stratosphere, where they react with ozone by ultraviolet rays, eventually destroying the ozone layer. The Montreal Protocol for the Protection of Ozone Layers came into effect. For this reason, hydrofluorocarbons (HFC) such as 1,1,1,2-tetrafluoroethane (R-134a) have emerged as alternative refrigerants. The hydrofluorocarbon is not concerned with destroying the ozone layer, but it has been found to not only directly contribute to global warming as a greenhouse gas, but also to indirectly contribute to global warming due to low energy efficiency of the refrigeration system developed using the same. Therefore, there is a need to replace HFC with another refrigerant. Recently, it is a natural refrigerant that has emerged as an alternative refrigerant for HFC, and among them, a refrigeration apparatus using hydrocarbons is commercialized.

In general, refrigeration oil used in the compressor of the refrigerating device serves to lubricate, cool, and seal the operating site. In recent years, refrigeration oil has become increasingly harsh due to energy savings, compact size of compressor, low noise and high efficiency. Therefore, in order to secure the reliability of the compressor, it is essential to use a refrigeration oil having excellent lubricity and excellent wear resistance. In particular, in order to increase the efficiency of the refrigerator, the viscosity of the refrigerator oil is gradually decreasing, and the refrigerant compressor protection performance of the low viscosity refrigerator oil is one of important characteristics.

As described above, various types of refrigerator oil have been proposed for use in a refrigeration apparatus using a hydrocarbon as a refrigerant. According to Korean Patent No. 476400 and US Patent No. 6,495,062, a composition for a compressed refrigerator using a base oil formed of a hydrocarbon compound having a non-aromatic unsaturation of 10% or less and a kinematic viscosity at 100 ° C of 5 mm 2 / s or more is disclosed. have. Korean Patent Publication No. 2002-68389 discloses a refrigerator oil in which a polyether compound and a mineral oil component are mixed. Korean Patent Publication No. 2004-7307 proposes a refrigerating oil having an ether compound as a main component and having a viscosity of 40 ° C. of 10 to 100 mm 2 / s. Korean Patent Publication No. 2004-11665 discloses refrigeration oil as a main component of one or more esters selected from one or more neopentylpolyols having 5 to 10 carbon atoms and linear or branched monovalent fatty acids having 5 to 9 carbon atoms. In addition, WO 2000/60031 (EP 1 092 760 B1) discloses a lubricating oil whose main component is mineral oil. In addition, Korean Patent Publication No. 2003-95987 discloses 5 to 30% by weight of oil having a boiling point of 300 ° C or lower by gas chromatography method and 5 to 35% by weight of oil having a boiling point of 500 ° C or higher by the same method. In addition, the 20% distillation temperature by the same method was 250 ° C or higher,% Cp was 35% or more in the ndM ring analysis, the nitrogen content was 10 ppm or less, the kinematic viscosity was 7-150 mm 2 / at the pour point -20 ° C or 40 ° C. A refrigerator oil composition in the range of s is disclosed.

However, synthetic oils such as polyether compounds, ether compounds, neopentyl polyol, and the like in the aforementioned prior arts are limited in use because they are more expensive than mineral oil-based refrigeration oils. On the other hand, in the case of the refrigeration oil disclosed in WO 2000/60031, there is a problem that sludge is formed on the compressor discharge side when used for a long time in the patent application No. 2003-95987 of the same applicant, and the sliding part is worn, which interferes with the operation This has been pointed out. In this regard, Patent Publication No. 2003-95987 discloses that refrigeration oil having a desired viscosity can be prepared using an oil having a boiling point of 300 ° C. or lower and an oil having a temperature of 500 ° C. or higher according to the distillation test method by gas chromatography. It is starting.

Accordingly, the present inventors have continuously studied to overcome the above-mentioned limitations of the prior art. As a result, the low-temperature fluidity and durability of the refrigeration oil are increased in order to increase the efficiency of the refrigerating device, to reduce the noise, and to allow the refrigerant compressor to operate reliably for a long time. And it is to develop a refrigeration oil that significantly improved the compressor protection performance.

Accordingly, an object of the present invention is to provide a lubricant base oil suitable for a refrigerator oil for a refrigerator using a hydrocarbon-based refrigerant.

Another object of the present invention to provide a refrigeration oil prepared using the lubricant base oil.

The lubricant base oil provided according to the first aspect of the present invention has a viscosity at 40 ° C of 5-20 mm2 / s, (ii) viscosity index of 90 or more, (iii) aniline point of 90 or more, and (iv) pour point -35 ° C or less, (i) 0.1% by weight or less of aromatics, (i) 1 ppm or less of sulfur and nitrogen, and (i) 20% distillation temperature in simulated distillation according to ASTM D 2887. 300 ° C. or more, 50% effluent temperature is 350 ° C. or more, and 90% effluent temperature is 400 ° C. or more. Preferably, the lubricating base oil is subjected to a reduced pressure classification of unconverted oil (UCO) produced by the fuel oil hydrocracking process of converting the vacuum gas oil (VGO) into light fuel oil; Catalytic dewaxing the vacuum fractionated fractions respectively; Performing a hydrofinishing reaction of the dewaxed fraction; And removing light hydrocarbons from the hydrogenation finishing reaction product through fractional distillation.

The refrigerator oil provided according to the second aspect of the present invention is characterized in that it contains the lubricant base oil.

Hereinafter, the present invention can be achieved by the following description with reference to the accompanying drawings.

In the case of the lubricating base oil provided according to the present invention, the wax component is sufficiently removed by depth dewaxing to achieve a low pour point of -37 ° C. or less, thereby solving the problem of high kinematic viscosity, which is a fatal disadvantage of the conventional paraffinic refrigeration oil. Typically, mineral oil-based refrigeration oils have been produced with lead-based base oils. This is because in the case of the lead-based base oil, the wax component is less and the pour point is lower than that of the paraffin base oil. However, the lead-based base oil has a problem in that oxidative stability is inferior to that of the paraffinic base oil and thus deteriorated when used for a long time, and sludge is produced. The lube base oil provided according to the present invention has a% Cp content of 70 or more according to ASTM D 2140, a% Cn of 30 or less, and a large amount of paraffins, and hardly contains an aromatic component. Can solve the shortage problem.

The refrigeration oil provided according to the present invention has a high viscosity index because it uses paraffinic base oil, which can improve the sealing property of the refrigeration system and help increase the efficiency of the refrigeration apparatus because the high temperature compressibility is large in the lead-based base oil. In addition, the molecular structure of the paraffinic base oil is similar to that of the refrigerant, which is excellent in mixing with the hydrocarbon refrigerant.

In particular, when considering the trend that the viscosity of the freezer oil is lowered to increase the efficiency of the refrigeration device, the freezer oil according to the present invention has a high viscosity index, which is advantageous for oil circulation at low temperatures compared to other freezer oil, In the temperature zone where the actual compressor lubrication is required, the viscosity is relatively high, which is excellent in preventing the wear of the compressor. In addition, when manufacturing a low viscosity refrigeration oil using the base oil prepared by a method other than the above-described process, in order to meet the low flow point required by the refrigeration oil, it is inevitable to use a base oil having a low boiling range. In this case, since the low boiling point oil used has a relatively low viscosity and can form a thin oil film, it may cause wear of the compressor. In order to prevent this phenomenon, a mixture of high boiling oil may be used, but in the case of high boiling oil, wax component is included, and such wax component is precipitated at a low temperature region such as an expansion valve or an evaporator to block the flow path or the surface of the device. It can stick to and reduce the efficiency of the refrigeration unit.

From this point of view, the present invention has excellent performance as a lubricant for a compressed refrigerator using a refrigerant containing hydrocarbon as a main component, i.e., a refrigeration cycle, and as a result, it can be used stably over a long period of time while reducing wear of equipment. It has the advantage of further improving the refrigeration efficiency.

As the refrigeration oil for hydrocarbon refrigerant according to the present invention, lubricant base oil produced by the process described below is preferably used. However, it should be noted that the following description is a preferred embodiment and the present invention is not limited thereto.

end. Lubricant base oil

When crude oil is fractionally distilled at atmospheric pressure to obtain the desired petroleum products, distillation under reduced pressure, the heavy oil residue remaining at the bottom of the atmospheric distillation column, is obtained under reduced pressure gas oil (VGO). Pressure-reduced gas oil is hydro-treating (HDT) in a low liquid space velocity (LHSV) of about 2.0 to 2.5 / hr, pressure of about 160 to 180 kg / cm2, temperature of about 350 to 370 ° C, and hydrogen inflow rate. Treatment is carried out under conditions of about 5,400 to 5,700 SCF / Bbl and in the presence of an HC-K catalyst (eg from Haldor Topseo). The catalyst is a coating of precious metals Pt and Pd on mesopore zeolites.

Then, as described above, with the unconverted oil (in the case of recycle mode) recycled as described later, the fraction subjected to the hydrotreatment, LHSV about 1.30 to 1.50 / hr, pressure about 160 to 180 kg / cm 2, temperature about 360 A reduced pressure gas oil hydrocracking process is carried out under conditions of ˜380 ° C. and a hydrogen inflow rate of about 7,300 to 7,600 SCF / Bbl, and in the presence of a HC-22 catalyst (eg, Haldor Topseo catalyst). The catalyst is a coating of precious metals Pt and Pd on mesopore zeolites.

In the above-described process configuration, it is practically impossible to operate the reactor per pass at 100% in the process of converting the heavy gas decompressed gas oil into the light fuel oil (typically about 50 to 90%). As a result, unconverted oil is always produced in the final fractionation stage.

At this time, by recycling the unconverted oil, the unconverted oil (UCO 1) in the recycle mode, which is Busan, when the total conversion rate is 67%, and the unconverted oil (UCO 2), which is Busan, when the conversion rate is 65%, is not recycled. have. In this case, a crude separator and light fuel oil having a boiling point of 380 ° C. or less can be recovered through a conventional separator and several fractional distillation steps, and unconverted oil can be obtained.

Unconverted oil which is not converted to light fuel oil during the hydrocracking reaction has an aromatic and hetero-compound which is not desirable in lubricating base oil, as well as an oil having a suitable viscosity as lubricating base oil. If it is possible to produce a lubricant base oil of excellent quality.

The unconverted oil is injected into a reduced pressure distillation process to give a top pressure of about 50 to 100 mmHg (typically about 75 mmHg), a top temperature of about 70 to 100 ° C (typically about 80 ° C), and a bottom pressure of about Distillation under reduced pressure at 100-200 mmHg (typically about 150 mmHg) and top and bottom temperature of about 300-350 degreeC (typically about 325 degreeC), for example, extract 70D and 100D can be obtained. . The oils of 70D and 100D thus obtained are catalysts containing platinum to carry out dewaxing by catalytic dewaxing, more preferably isomerization, in order to improve low temperature fluidity and increase paraffinic compound content. And treatment under conditions of low liquid space velocity of about 0.5-2.0 / hr, pressure of about 130-980 psig, and temperature of about 260-380 ° C. under hydrogen inlet to reach the desired pour point. A hydrofinishing process is then typically performed to impart ultraviolet stability to the treated fraction and maintain the artonization balance, preferably at least about 85 vol%. In the case of the hydrogenation finishing process, preferably, a low liquid space velocity of about 0.5 to 2 / hr, a pressure of about 1,600 to 3,000 psig, preferably about 1,900 to 2,700 psig, and a temperature of about 180 to 320 under a catalyst containing palladium and hydrogen inflow. Treatment with conditions of ℃, preferably about 220 ~ 280 ℃, then fractional distillation to remove the hard oil as shown in Table 1, high paraffin content, sulfur compounds, nitrogen compounds, and aromatic components almost no viscosity index High lube base oils (base oils 1, 2 and 3) can be obtained. Exemplary characteristics of the three base oils are shown in Table 1 below.

Lubricant base oil properties Base oil 1 Base oil 2 Base oil 3 Density @ 15 ℃ g / cm3 0.8324 0.8339 0.8319 Color ASTM 0 0 0 Kinematic viscosity (@ 40 ℃), ㎡ / s 8.02 10.14 12.16 Kinematic viscosity (@ 100 ℃), ㎠ / s 2.28 2.69 2.99 Viscosity index 92 102 100 Flash point (℃) 168 192 192 Pour point (℃) -39 -40 -42 Computer Value (mg KOH / g) <0.01 <0.01 <0.01 Aniline point (℃) 94 106 108 Cp / Cn / Ca (%) 70/30/0 71.5 / 28.5 / 0 73.3 / 26.7 / 0 S (ppm) <1 <1 <1 N (ppm) <1 <1 <1 20% outlet temperature (℃) 304 330 358 50% outlet temperature (℃) 356 371 385

In the present invention, the lubricating base oil may further include one or more base oils selected from the group consisting of polyol esters, alkyl benzenes, and lead-based base oils, in which the available amount is about 5% by weight or more, preferably about 5% by weight. 95 wt%.

I. additive

Various additives known in the art can be used in the manufacture of the refrigeration oil of the present invention can be used in combination with one or two, the typical additive components are as follows. However, if the type suitable for the production of the refrigeration oil while maintaining the properties of the above-described lubricant base oil can be adopted without particular limitation.

In the case of antiwear agents, phosphate-based antiwear agents such as trialkylphosphates and triaryl phosphates can typically be used. Specific examples of the trialkyl phosphate include tributyl phosphate, tripentyl phosphate, trihexyl phosphate, and the like, and triphenyl phosphate, tricresyl phosphate and the like as triaryl phosphate.

On the other hand, as an additive for improving the oxidation stability, a phenolic antioxidant such as 2,6-di-t-butyl-4-alkylphenol or an amine antioxidant such as dialkyldiamine can be preferably used. In addition, benzotriazole can be used as a metal inert agent.

The antifoaming agent may be a silicone-based, specifically, polysiloxane type antifoaming agent, and more specifically, silicone oil or polydimethylsiloxane may be used, and the amount of the antifoaming agent is preferably in the range of about 0.001 to 0.3% by weight.

The mixing amount of the additives is preferably about 5% by weight or less, more preferably about 1% by weight or less, in consideration of economical efficiency and the addition effect, based on the total weight of the refrigerator oil.

Example

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these examples.

The base oil and the additive components were mixed at 50 to 60 ° C., and the durability of the freezer oil was evaluated using a test apparatus that simulates the actual refrigeration system, as shown in FIG. 1, and the wear resistance was evaluated by the ASTM D 3233 method. The results are shown in Table 3.

Oil durability test

In order to evaluate the durability of the refrigerator oil according to the present invention was used a test refrigeration system as shown in FIG. R600a and the refrigeration oil according to the present invention were injected into the compressor and tested for 1344 hours at a temperature of 32.5 ± 5 ° C. At this time, the discharge pressure of the compressor was 7 kg / cm 2.

Abrasion Resistance Test

Seizure loads were obtained according to the ASTM D-3233 method with a closed Falex friction tester. The test conditions were refrigerant flow rate 100 ml / min and temperature 40 degreeC.

Comparative Examples 1 and 2

To prepare a composition in the same manner as in Example, Comparative Example 1 used a base oil prepared in a general manner, Comparative Example 2 uses a lead-based base oil. Table 2 shows the physical properties of the general mineral oil base oil (comparative base oil 1) and the lead-based base oil (comparative base oil 2) of the viscosity range similar to the base oil according to the present invention.

Comparative base 1 Base oil 2 Density @ 15 ℃ g / cm3 0.868 0.890 Color ASTM L0.5 L0.5 Kinematic viscosity (㎡ / s) @ 40 ℃ 9.60 9.65 @ 100 ℃ 2.52 2.30 Viscosity index 81 28 Flash point (℃) 160 158 Pour point (℃) -27.5 <-60.0 Computer Value (mg KOH / g) 0.01 0.01 Aniline point (℃) 75 60 Cp / Cn / Ca,% 58/32/10 42/44/14 S, ppm 80 130 N, ppm 7 10

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Base oil 1 99.6 Base oil 2 99.6 Base oil 2 99.6 Comparative base 1 99.6 Base oil 2 99.6 Tricrecyl Phosphate 0.3 0.3 0.3 0.3 0.3 Di-t-Butyl-P-Cresol (DTBC) 0.1 0.1 0.1 0.1 0.1 Oil durability test Change in flow rate through the capillary tube (%) 4.5 5 4.8 11 15 Oil color, ASTM L0.5 L0.5 L0.5 2.0 3.0 Compressor Parts Wear Rating Good Good Good Fine wear Fine wear Falex test results, lb 540 560 560 500 490

As can be seen from the above table, the refrigeration oil produced using the lubricating base oil according to the present invention can be used stably for a long time while reducing the wear of the device compared to the case of using a conventionally known lubricating base oil, further improving the refrigeration efficiency It was confirmed that it can be made.

As described above, the refrigeration oil using the lubricating base oil according to the present invention increases the efficiency of the refrigerating device, reduces the noise, and significantly reduces the low temperature fluidity, durability and compressor protection performance required for the refrigerant compressor to operate reliably for a long time. It can be seen that the improvement.

Simple modifications and variations of the present invention can be readily used by those skilled in the art, and all such variations or modifications can be considered to be included within the scope of the present invention.

Claims (5)

(Iii) the viscosity at 40 ° C. is 5-20 mm 2 / s, (ii) the viscosity index is 90 or more, (i) the aniline point is 90 or more, (iv) the pour point is -35 ° C. or less, and (iv) 0.1% by weight of aromatic components (I) sulfur content and nitrogen content of 1 ppm or less, and (iii) 20% effluent temperature in the simulated distillation test according to ASTM D 2887 is 300 ° C or more, 50% effluent temperature is 350 ° C or more, and 90 Lubricant oil for refrigerator oil production, characterized in that the% outlet temperature is 400 ℃ or more. The method of claim 1, further comprising the steps of: distilling under reduced pressure the unconverted oil by-produced in the fuel oil hydrocracking process in which the lubricating base oil converts the reduced pressure gas oil into light fuel oil; Catalytic dewaxing the fractionated fractions respectively; Performing a hydrofinishing reaction of the dewaxed fraction; And removing light hydrocarbons from the hydrogenation finishing reaction product through fractional distillation. The lubricating base oil of claim 1, wherein the lubricating base oil further comprises 5 to 95% by weight of one or more base oils selected from the group consisting of polyol esters, alkyl benzenes, and lead-based base oils. Refrigerator oil comprising the lubricant base oil according to any one of claims 1 to 3. The refrigerator oil according to claim 4, further comprising an additive selected from the group consisting of phosphate antiwear agents, phenolic or amine antioxidants, and silicone antifoaming agents.

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