KR20100022473A - Vegetable oil dielectric fluid composition - Google Patents

Abstract

An electrical device having therein a dielectric fluid composition, wherein the dielectric fluid composition includes at least one refined, bleached and deodorized vegetable oil and at least one antioxidant, wherein the dielectric fluid composition has a pour point of less than about -20 °C as measured according to either of ASTM D97 or ASTM D5950.

Description

Vegetable oil dielectric fluid composition {VEGETABLE OIL DIELECTRIC FLUID COMPOSITION}

The present disclosure relates to dielectric fluids for use in electrical devices.

Dielectric (or insulating) fluid compositions used in electrical distribution and power equipment act as electrical insulating media, ie exhibit dielectric strength, and transport heat generated away from the equipment. Ie act as cooling medium. For example, when used in a transformer, dielectric fluid transports heat from the windings and cores of the transformer or connection circuit to the cooling surface.

Liquid filled electrical devices used in certain climates may require dielectric fluid compositions that maintain electrical and physical properties, particularly fluidity, for long periods at low temperatures. This flowability requirement limits the scope of application for vegetable oil-based dielectric fluid compositions that typically have a pour point of about −10 ° C. or more.

Summary of the Invention

Because some electrical devices use large amounts of dielectric fluid and the dielectric fluid can remain in the device for a long period of time, there is a possibility that the dielectric fluid can enter the environment during the operating life of the device. To produce a dielectric fluid with improved low temperature performance, the vegetable oil base fluid may be blended with petroleum based mineral oils or silicones or formulated with significant amounts of non-biobased synthetic additives. In many cases, however, such additives are expensive and / or toxic, and / or biodegradable, and accidental spills or leaks from electrical devices can damage the surrounding environment.

In one embodiment, the present disclosure is directed to a dielectric fluid composition comprising one or more refined, bleached and deoderized vegetable oils. This RBD vegetable oil is measured according to ASTM D97 or ASTM D5950, which has a sufficiently low pour point (less than about -20 ° C, preferably less than about -25 ° C, ASTM D97 or ASTM D5950 to make the composition very suitable for use in electrical devices, especially in cold climates). When). Such RBD vegetable oils can be used in the compositions, dielectric fluid compositions and methods according to other aspects of the invention cited herein.

In one aspect, the present disclosure relates to a composition comprising at least one vegetable oil and at least one antioxidant, wherein the composition has a pour point of less than about −20 ° C. as measured according to ASTM D97 or ASTM D5950.

In another aspect, the present disclosure relates to a composition comprising at least one vegetable oil, at least one antioxidant, and at least one pour point depressant, wherein the composition has a pour point of less than about −30 ° C. as measured according to ASTM D97 or ASTM D5950. Has

In another aspect, the present disclosure provides a dielectric fluid comprising one or more rapeseed oil and synthetic esters selected from Brassica Juneca , Brassica Campestris, and combinations thereof. It relates to a composition.

The dielectric fluid composition can be used, for example, in electrical devices such as transformers, switchgears, regulators, reclosers.

In another aspect, the present disclosure relates to a method of making a dielectric fluid, the method comprising one or more tablets, bleaching and deodorizing having a pour point of less than about -20 ° C. as measured by one or more of ASTM D97 and ASTM D5950. Providing rapeseed oil, treating rapeseed oil with clay, and filtering the rapeseed oil to produce treated rapeseed oil.

The dielectric fluid compositions described herein have good electrical properties even when formulated with small amounts of non-biobased compounds. In some embodiments, the dielectric fluid composition comprises (1) easy biodegradability as defined by USEPA OPPTS 835.3110, (2) final biodegradability as defined by USEPA OPPTS.3100, and (3) method OECD 301 Qualify as one or more of biodegradability as measured by The excellent low temperature performance of the vegetable oil dielectric fluid composition, as well as the environmentally safe biological properties of the composition, permit the use of the fluid in climatic areas and devices where vegetable oil based fluids have not previously been used. Since many components of the vegetable oil dielectric composition are derived from renewable seed based resources, the fluid can be easily produced at a reasonable cost.

The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention can be readily understood from the description and drawings, and from the claims.

Brief description of the drawings

1 is a cross-sectional view of a transformer including a vegetable oil fluid composition.

FIG. 2 is a plot showing the viscosity of a dielectric fluid over time at temperatures between −10 ° C. and −20 ° C. FIG.

details

The present disclosure relates to dielectric fluid compositions comprising one or more purified, bleached and deodorized (RBD) vegetable oils. This RBD vegetable oil has a pour point of less than about −20 ° C., preferably less than about −25 ° C. as measured according to ASTM D97 or ASTM D5950. This low pour point makes the dielectric fluid compositions comprising RBD vegetable oils well suited for use in electrostatics, especially in cold climates.

In one embodiment, the present disclosure relates to a dielectric fluid composition comprising one or more RBD vegetable oils and antioxidants. The dielectric fluid composition has a pour point of less than about −20 ° C., preferably less than about −25 ° C.

As used herein, the term RBD vegetable oil means crude vegetable oil that has been further processed in a vegetable oil refinery. Typically, to prepare RBD vegetable oils, crude vegetable oils are degumming by addition of water, after alkali purification with a base such as NaOH, bleached with clay, and deodorized using vacuum steam stripping. RBD treatment of such oils is well known in the art. The treatment step removes contaminants from crude vegetable oils that cause poor dielectric performance. Crude vegetable oils may also contain more wax components that result in less desirable low temperature performance.

The pour point of the dielectric fluid composition can be measured by two different methods, ASTM D97 or ASTM D5950 (pour point measurements according to the test methods herein can vary by ± 3 ° C). ASTM D97, a manual technique, is an accepted standard test method for determining the pour point in the electrical equipment industry. However, automated equipment for measuring pour points can in some cases provide improved speed and consistency in accordance with ASTM Method D5950. However, while the D5950 method has not yet been accepted in the electrical industry, the lubricating fluid industry has been shifted to the D5950 automated method and is tolerated.

Vegetable oils are preferably obtained by treating naturally occurring (non-genetically modified (or non-GMO)) seed stocks, but also oils obtained from genetically modified (GMO) seeds or from GMO and non-GMO seeds. Can be obtained from blend of.

One suitable vegetable oil for the dielectric fluid composition can be obtained by treating GMO rapeseed, non-GMO rapeseed, and combinations thereof. Preferred oils are preferably obtained from seeds grown in the Nordic region. Oil from non-GMO "winter" rapeseed grown in the Nordic climate has a very low pour point and is suitable for use in electrical equipment operated in cold climates. Particular preference is given to oils obtained from the seeds of the Brassica Zunega and Brassica Campestris plants, suitable oils available from Cargil, Inc. (Minneapolis, Minnesota) under the trade name Agri-Pure 60 Rapeseed Oil.

While not wishing to be bound by any theory, currently available evidence shows that RBD oils obtained from Nordic Rapeseeds, such as Brassica Zuneca and Brassica Campestris seeds, can be measured according to ASTM D97 or ASTM D5950. When present, it appears to have a fatty acid distribution that results in a pour point of less than about -20 ° C, preferably less than about -25 ° C. Other RBD rapeseed oils, such as those available from North American seed stocks, exhibit much higher pour points from about -10 ° C to about -16 ° C. Compared to these North American oils, Nordic Rapeseed oil derived from Brasca Zuneca and Brasca Campestris can provide significant advantages in low temperature applications.

Brasca Juneca and Brasca Campestris oils used in the dielectric fluid composition can be obtained from a single year harvest, or a vegetable oil dielectric fluid composition having the desired electrical, chemical and physical properties by blending oils from various cultivars Can be provided.

In addition to the particularly low pour point, the dielectric fluid compositions comprising the preferred RBD Brassica Geneca and Brassica Campestris oil have good electrical properties after proper treatment.

The dielectric fluid composition preferably has an dielectric strength of at least about 55 kV, preferably greater than about 60 kV. This dielectric strength can be measured according to ASTM method D1816 using a 0.08 inch (2 mm) gap between VDE electrodes. Determination of dielectric strength is well known in the art and is within the knowledge of those skilled in the art.

The dielectric fluid composition also preferably has a flash point above 300 ° C as well as a flash point above about 275 ° C. Both flash point and flash point can be measured by ASTM D92. Determination of the ignition point is well known in the art and is within the knowledge of those skilled in the art.

The dielectric fluid composition also preferably has a dissipation factor at 25 ° C. that is less than about 0.1% and a dissipation factor at 100 ° C. of less than about 4%. This dissipation factor can be measured using ASTM D924. Determination of the dissipation factor is well known in the art and is within the knowledge of those skilled in the art.

Other electrical, chemical and physical properties are described in Table 4 below.

To ensure that the dielectric fluid composition remains flowable at relatively low temperatures, the vegetable oils used in the composition have a kinematic viscocity of 2 to 15 cSt at 100 ° C. and a dynamic viscosity of less than 110 cSt at 40 ° C. It is desirable to have. Preferably, the fluid used in the dielectric fluid composition has a dynamic viscosity of about 20 cSt to about 50 cSt at 40 ° C.

A common method of measuring dynamic viscosity at 40/100 ° C. is ASTM D445, but different techniques may be used at -10 ° C. and −20 ° C. cold temperatures and at colder cold temperatures. Yield stress and viscosity are measured using a Canon mini-rotary viscometer (MRV) in accordance with ASTM D3829. This MRV acts as a concentric cylindrical viscometer whose yield stress is determined by observing the movement of the cylinder under different applied stresses. For example, a 5 g weight can be used to apply the yield stress, and the viscosity can be determined by measuring the time it takes to achieve three revolutions. The time is multiplied by a constant depending on the cell used for the measurement and the stress applied to determine the dynamic voscosity of centipoise (cP). The kinematic viscosity (cP) is converted to the dynamic viscosity of the centistoke (cSt) obtained by dividing the kinematic viscosity by the density of the fluid at the particular temperature of the measurement. Determination of viscosity is well known in the art and is within the knowledge of those skilled in the art.

For example, the density can be determined using a 250 ml volumetric flask with a 15 ml graduated cylinder on the neck. The internal volume is calibrated with water at a known temperature and mass before measuring the fluid. The density of the fluid at temperature is calculated using the measured volume and the weight of the fluid.

The vegetable oil dielectric fluid composition further comprises one or more antioxidant compounds. Useful antioxidant compounds include, for example, BHA (butylated hydroxyanisole), BHT (butylated hydroxytoluene), TBHQ (tert-butylhydroxyquinone), THBP (tetrahydrobutrophen), ascorbyl Palmitate (rosemary oil), propyl gallate, and alpha-, beta- or delta-tocopherol (vitamin E).

The antioxidant compound may be present in the dielectric fluid composition at less than about 1 weight percent, preferably less than about 0.5 weight percent based on the total weight of the composition.

In addition to the preferred rapeseed oils such as Brassica Junek and Brassica Campestris , any of the dielectric fluid compositions described herein may include other vegetable oils, optionally as modifiers or as modifying properties, including adjusting the pour point. Can be. Any commercially available seed oil may be used, and suitable additional vegetable oils are, for example, soybeans, sunflower, crabe, corn, olives, cotton, safflower, vernonia, resquelara (lesquerella) and combinations thereof, including but not limited to. Of these additional oils, soybean oil and sunflower oil are preferred.

Additional vegetable oils may be present or used in any amount so long as their presence does not substantially degrade the physical, chemical and electrical properties of the composition.

 In other embodiments, the vegetable oil dielectric fluid composition comprises one or more vegetable oils as described above, one or more antioxidants as described above, and one or more pour point depressants. A wide variety of compounds can be used as the pour point depressant, and preferred pour point depressants include polyvinyl acetate oligomers and polymers and / or acrylic oligomers and polymers. Suitable pour point depressant compounds include (meth) acrylates such as those available from Rohmax (Philadelphia, PA) under the trade name Viscoplex. Alkyl methacrylates having a molecular weight of about 200,000, such as Viscoplex 10-310, have been found to be particularly suitable.

Pour point depressants can be used alone or can be further diluted with vegetable oil. Suitable vegetable oil diluted pour point depressants include, for example, vegetable oil diluted alkyl methacrylates available from Functional Products (Macedonia, Ohio) under the trade name PD-551.

The pour point depressant is present in the vegetable oil dielectric fluid composition at up to about 4% by weight, preferably from about 0.2% to about 2% by weight, more preferably from about 0.4% to 2% by weight.

Vegetable oil dielectric fluid compositions comprising antioxidants and pour point depressants typically have a pour point of less than about −30 ° C., preferably less than about −33 ° C., as measured by one or more of ASTM D97 and ASTM D5950. . Vegetable oil dielectric fluid compositions comprising such additives typically have a flash point above about 300 ° C., preferably above about 350 ° C., and a flash point above about 275 ° C., preferably above 325 ° C. Other properties of typical vegetable oil dielectric fluid compositions with additives are described in Table 5 below.

Any of the dielectric fluid compositions described herein may optionally include small amounts of one or more additives to inhibit the growth of microorganisms. Any antimicrobial material compatible with the dielectric fluid can be blended into the fluid. In some cases, compounds useful as antioxidants may also be used as antibacterial agents. For example, phenolic antioxidants such as BHA also exhibit some activity against bacteria, fungi, viruses and protozoa, especially when used with other antimicrobial agents such as potassium sorbate, sorbic acid or monoglycerides. It is known. Vitamin E, ascorbyl palmitate and other known compounds are also suitable for use as antimicrobial additives.

Any of the vegetable oil dielectric fluid compositions described herein may optionally further include colorants such as dyes or pigments. Any known dye or pigment can be used for this purpose and many are commercially available as food additives. The most useful dyes and pigments are those that are oil soluble. The colorant is present in the composition in trace amounts, typically less than about 1 ppm.

In suitable circumstances, any of the vegetable oil dielectric fluid compositions described herein may optionally comprise minor amounts of one or more petroleum derived oils such as, for example, mineral oils and / or polyalphaolefins. Mineral oils derived from naphthenic and paraffinic sources are typically refined and treated with transformer fluids that meet the electrical industry standard according to ASTM D3687. Suitable mineral oil-based dielectric fluids are, for example, those available from Petro-Canada under the trade name Luminol TR, those available from Calumet Lubricating Co. under the trade name Caltran 60-15, and those available from Ergon Refining Inc. under the trade name Hivolt II. Things are included. Suitable polyalphaolefins have a viscosity of about 2 cSt to about 14 cSt at 100 ° C. and are available from Chevron under the tradename Synfluid PAO, from Amoco under the tradename Durasyn, and from Ethyl Corp. under the tradename Ethylflo. Particularly preferred polyalphaolefins have a viscosity of about 4 cSt to about 8 cSt and are derived from dimers, trimers and tetramers of 10 carbon atom chains. For polyalphaolefins the most preferred viscosity range is from about 6 cSt to about 8 cSt.

Petroleum derived oils and polyalphaolefins may be incorporated into the composition at less than about 10 weight percent, preferably less than about 5 weight percent.

In another embodiment, the present disclosure is directed to a vegetable oil dielectric fluid composition comprising one or more vegetable oils described above, and a synthetic ester compound. In addition to one or more vegetable oils and synthetic esters, the vegetable oil dielectric fluid composition preferably further comprises an antioxidant as described above and a pour point depressant as described above.

The synthetic esters may be blended with the vegetable oil and other optional ingredients in an amount sufficient to modify the properties of the dielectric fluid composition, particularly to further lower the pour point for certain cold and hot applications. As used herein, the term “synthetic ester” refers to (1) bio-based or petroleum-derived polyols and (2) linear or branched organic acids, which may be bio-based or petroleum derived. It means the ester produced by the reaction. The term polyol, as used herein, means an alcohol having two or more hydroxyl groups.

While synthetic esters may be derived from biobased compounds, petroleum by-products or combinations thereof, biobased esters derived from renewable compounds produced by animals and plants are preferred.

As used herein, the term "biosystem" means a compound derived from a substance produced by an animal and / or a naturally occurring or cultivated plant. Plant and animal sources for biobased compounds can be GMO, non-GMO and combinations thereof, with non-GMO sources being preferred. The term "bio-based" refers to USDA FB4P (2002 Farm Bill), for example 70 Fed. Reg. 1792 (January 11, 2005) and 71 Fed. Reg. 59862 (October 11, 2006) (to be codified at 7 C.F.R.pt. 2902).

Suitable examples of bio-based synthetic esters include those produced by reacting polyols with organic acids having a chain length of C8-C10 derived from vegetable oils such as, for example, coconut oil. Suitable synthetic esters are available from Cargill (Brazil) under the trade name Innovatti as well as from Hatco Chemical Co. (Kearney, NJ). Among these synthetic esters, not only synthetic pentaerythritol with the C7-C9 group available from Copper Power Systems under the tradename Envirotemp 200 (E200) and from Hatco Chemical Co. under the tradename Hatco 5005, but also from Innovatti under the tradename Exp 1906 and under the tradename Hatco 2938 Trimethylolpropane (TMP) esters with C8-C10 groups, available from Hatco Chemical Co. Other polyols suitable for reacting with organic acids to form synthetic esters are, for example, neopentyl alcohol, dipentaerythritol, and 2-ethylhexyl, n-octyl, isooctyl, isononyl, isodecyl and tridecyl alcohol Included.

Synthetic esters may be used in the vegetable oil dielectric fluid composition at up to about 70 weight percent, preferably from about 30 weight percent to about 70 weight percent, even more preferably from about 25 weight percent to about 70 weight percent. In general, large amounts of synthetic esters result in dielectric fluid compositions with lower pour points. For example, according to one or more of ASTM D97 and ASTM D5950, some vegetable oil fluid compositions comprising up to about 30 weight percent synthetic ester have a pour point less than about -38 ° C., but up to about 70 weight percent synthetic ester. Some compositions comprising have a pour point of less than about -50 ° C.

Although incorporation of non-bio-based synthetic materials may improve certain properties of the vegetable oil dielectric fluid compositions described above, adding such compounds may also increase costs and reduce the "environmentally friendly" nature of the composition. have. In order to ensure that spills or leaks of vegetable oil dielectric fluid compositions do not significantly affect the environment, the compositions are preferably biodegradable, nontoxic, and formulated with trace amounts of non-biobased materials. The vegetable oil dielectric fluid composition preferably comprises at least 70% bio-based material, more preferably at least about 72.5% bio-based material.

For example, the bio-based content can be determined using the ASTM method and is based on the amount of bio-based carbon in the material as% of total organic carbon mass in the product.

The vegetable oil dielectric fluid composition described above is also preferably formulated to include trace amounts of non-biodegradable material. The amount of synthetic and / or non-biodegradable additives in a vegetable oil dielectric fluid composition may be determined by the composition as defined by (1) easy biodegradability as defined by USEPA OPPTS 835.3110, and (2) as defined by USEPA OPPTS.3100. It is desirable that it be limited to qualify as one or more of biodegradability, as measured by the method of biodegradable, and (3) method OECD 301.

Easy biodegradability as defined by USEPA OPPTS 835.3100 is an arbitrary classification of chemicals that have passed certain designated screening tests for ultimate biodegradability. This test is so stringent that it is performed on the assumption that such compounds are readily and completely biodegradable in an aqueous environment under aerobic conditions.

Final biodegradability, as defined by USEPA OPPTS 830.3100, means that organic compounds decay into CO ₂ , water, oxides or mineral salts of other elements, and / or products associated with normal metabolic processes of microorganisms.

The vegetable oil dielectric fluid composition described above is preferably formulated to be substantially free of GMO material, meaning that the composition comprises less than about 5% by weight of GMO material. Even more preferably, the composition is even more preferably substantially free of GMO material (less than about 1% by weight of GMO), most preferably not completely containing GMO material, which is preferably GMO excluding impurities. It does not exist in the composition at all. In this application, "substantially" does not exclude "completely". For example, compositions that are substantially free of GMO materials include those that may not be completely free of GMO materials. If necessary, the word "substantially" may be omitted from the definition of the present invention.

The vegetable oil dielectric fluid compositions described above can be prepared by taking commercially available refined, bleached and deodorized (RBD) vegetable oils and treating the oil to remove impurities to improve electrical properties. The RBD oil is typically processed by removing moisture and stirring with absorbents such as activated clay to remove impurities, which impurities can be detrimental to the electrical properties of the oil. In addition to or instead of the clay treatment step, the RBD oil may be heated and / or filtered to remove particles, microorganisms and the like.

Preferably, the RBD oil adds about 10% by weight heated clay (170 ° C.) to the heated oil with stirring. The oil is then filtered to remove clay particles containing the absorbed contaminants and then vacuumed to less than about 10 torr.

Typically, after carrying out this treatment step or similar treatment step, the preferred treated oil contains up to about 200 ppm water, more preferably up to about 100 ppm water.

After the impurity removal step, the treated oil can be used alone as the dielectric fluid in the electrical device. However, prior to use, the oil is typically blended with the additives described above, such as antioxidants, pour point depressants, colorants and the like. The treated oil can be further blended with additional vegetable oils, synthetic esters, synthetic or petroleum derived oils and the like to adjust its properties for a particular application.

In another embodiment, the present disclosure relates to an electrical device having therein a dielectric fluid composition comprising one or more RBD vegetable oils and antioxidants as described above. The dielectric fluid composition has a pour point of less than about −20 ° C., preferably less than about −25 ° C. as measured according to ASTM D97 or ASTM D5950. In addition to antioxidants, the dielectric fluid composition in the electrical device may further comprise any of the additives described above including, for example, pour point depressants, additional vegetable oils, synthetic esters, mineral oils, polyalphaolefins, and the like.

The vegetable oil dielectric fluid composition may be incorporated into any electrical equipment or device, including but not limited to transformers, switchgear, regulators, and reclosers.

For example, referring to FIG. 1, the transformer 10 includes a tank body 112 that encloses a transformer core coil assembly and a winding 15. The core coil assembly and the windings 15 are at least partially impregnated in the dielectric fluid 18. The space between the surface of the fluid 18 and the tank body 12 (referred to as the headspace 20) is an oxygen permeable vessel 24 containing a redox composition 22 as described in US 2005/0040375. May optionally include. For example, a prepackaged oxygen scavenging compound as commercially available under the trade names Ageless and Freshmax may be contained in a pouch consisting of an oxygen permeable polymer film, a polyester felt or a cellulose pressboard. The tank body 12 may also include any features, such as a threaded plug 28 with a view port 30 and a pressure relief device 40.

The dielectric fluid composition is preferably introduced into the electrical device in a manner that minimizes the exposure of the fluid to atmospheric oxygen, moisture and other contaminants that may adversely affect its performance. Preferred processes include drying the tank contents, evacuating, replacing air with dry nitrogen gas, filling under partial vacuum, and immediately sealing the tank. If the electrical device requires a headspace between the dielectric fluid and the tank cover, after the filling and sealing step of the tank, the gas in the headspace can be evacuated and replaced with an inert gas such as anhydrous nitrogen.

Electrical transformers and switchgear are typically structured by impregnating the core and windings and other electrical equipment in dielectric fluid and enclosing the impregnated components in a sealed housing or tank. Windings in larger equipment often also wrap with cellulose or paper material. The vegetable oil dielectric fluid compositions described herein can also be used to protect and extend the useful operating life of the cellulose chains of the paper insulation material. While not wishing to be bound by any theory, presently available evidence shows that the vegetable oil dielectric fluid absorbs water from the paper, preventing the paper from hydrolyzing and transesterifying the cellulose and further disintegrating the paper, It has been shown to provide long chain fatty acids which reduce paper breakdown, especially at high equipment operating temperatures.

The vegetable oil dielectric fluid composition may also be used to retrofill current electrical equipment incorporating other less desirable dielectric fluids. Retrofilling of current devices utilizes any suitable method known in the art, although elements of electrical equipment may be optionally dried prior to introduction of the vegetable oil based dielectric fluid due to the increased sensitivity of the vegetable oil fluid to moisture. Can be achieved. This is particularly useful when the equipment includes cellulose or paper wrapping that can absorb moisture over time. Because of the relatively high solubility of water in vegetable oils, vegetable oil fluids can themselves be used to dry current electrical equipment.

Example 1

Three different samples of RBD European Rapeseed Oil, representing at least three different crop years, were obtained and tested. The oil was obtained from a refinery in Anderlev, Belgium, which treated rapeseed from the preferred genus and species types Brassica Zuneca and Brassica Campestris .

The results are shown in Table 1 below.

Sample Harvest period Pour Point (℃) (ASTM D97) One 2004 -26 2 2005 -25 3 2006 -26

Example 2

Pour point of the following fluid was measured according to ASTM D97 and ASTM D5950, the results are shown in Table 2 below.

Sample Pour Point (℃) ASTM D97 Pour Point (℃) ASTM D5950 100% European Rapeseed / "as is" -21 -20 100% European Rapeseed / Clay Treatment-Additive-Free -21 -24

Example 3

Samples of European soybean oil and European rapeseed oil were obtained for analysis. The rapeseed oil was Cargil Agri-Pure 60 (Antebel, Belgium) and included the preferred genus and species types Brassica Zuneca and Brassica Campestris . Under the conditions as obtained, the RBD soybean oil had a pour point of about -10 to about -16 ° C according to ASTM D5950, while the RBD rapeseed oil had a pour point of -26 ° C.

The properties of these oils are shown in Table 3 below.

European Rapeseed Soybean oil moisture 37 ppm 66 ppm ^* Hereditary D1816 62 kV 46 kV ^* DF at 25 ° C 0.04% 0.21% DF at 100 ° C 1.91% 5.67% Acid 0.069 mg KOH / g 0.014 mg KOH / g IFT 28.6 dynes / cm 27.1 dynes / cm flash point 334 ℃ 334 ℃ flash point 358 ℃ 360 ℃ Pour point -26 ℃ -10 ℃

^{* After} 24 hours vacuum treatment, moisture = 1 ppm, D1816 = 54 kV

The RBD oil was then treated with clay, filtered and the resulting treated oil is shown in Table 4 below.

European Rapeseed Soybean oil moisture 3 ppm 1 ppm Hereditary D1816 71 kV 61 kV DF at 25 ° C 0.02% 0.01% DF at 100 ° C 0.39% 0.38% Acid 0.029 mg KOH / g 0.005 mg KOH / g IFT 32.0 dynes / cm 30.0 dynes / cm flash point 334 ℃ 336 ℃ flash point 358 ℃ 362 ℃ Pour point -21 ℃ -10 ℃ Viscosity at 40 ℃ 34.90 cSt 31.40 cSt Viscosity at 100 ° C 8.04 cSt 7.77 cSt

The treated oil was then blended with additives to enhance its performance as an electrically insulating fluid. The treated oil was blended with 0.40 wt% BHT antioxidant and 1.0 wt% Pour Point Depressant, Viscoplex 10-310 (commercially available from Rohmax, Philadelphia, PA).

The properties of the resulting blends are shown in Table 5 below.

European Rapeseed Soybean oil moisture 13 ppm 5 ppm Hereditary D1816 73 kV 66 kV DF at 25 ° C 0.02% 0.03% DF at 100 ° C 1.53% 1.75% Acid 0.047 mg KOH / g 0.028 mg KOH / g IFT 32.2 dynes / cm 31.6 dynes / cm flash point 332 ℃ 330 ℃ flash point 358 ℃ 360 ℃ Pour Point (D5950) -33 ℃ -26 ℃ Pour Point (D97) -31 ℃ -24 ℃ Viscosity at 40 ℃ 36.31 cSt 34.53 cSt Viscosity at 100 ° C 8.79 cSt 8.35 cSt Volume resistance 74 × 10 ¹² 51 × 10 ¹²

Example 4

As shown in Table 6 below, the European Rapeseed Oil of Example 2 was blended with various synthetic esters.

In Table 6 below, soybean oil means soybean oil derived dielectric fluid available from Copper Power Systems (Wikisha, Wis.) Under the trade name Envirotemp FR3 Fluid.

Bass fluid Synthetic ester E200 Synthetic esters EXP 1906 Pour Point (℃) (ASTM D5950) Pour Point (℃) (ASTM D97) Favorable side Ignition point ＞ 300 ℃ ＞ 70% bio-based and regenerated Example C1 30% Soybean Oil 0 70% -48 Yes (304 ℃) Yes Example C2 70% Soybean Oil 0 30% -33 -34 Yes (323 ℃) Yes Example 3-1 30% European Rapeseed 0 70% -50 Yes (303 ℃) Yes Example 3-2 70% European Rapeseed 0 30% -39 -38 Yes (321 ℃) Yes Example 3-3 30% European Rapeseed 70% 0 -51 Yes no Example 3-4 70% European Rapeseed 30% 0 -38 Yes no Example 3-5 72.5% European Rapeseed 0 27.5% -39 -40 Yes (327 ℃) Yes

The mod blends in Table 6 contained up to 1.0 wt% of the pour point depressant (available from Viscoplex 10-310, Rohmax) and up to 0.4 wt% of the antioxidant in vegetable oil.

C1 and C2 show comparative examples.

Synthetic pentaerythritol ester with group E200 = C7-C9 (available from Hatco Chmical Co. under the trade name Hatco 5005)

EXP 1906 = synthetic ester having a C8-C10 group (commercially available from Hatco Chemical Co. under the trade name Hatco 2938)

Comparing Example C2 with Examples 3-2 and 3-4, it was found that the cold and hot performance of European Rapeseed fluid was improved compared to soybean oil-based fluids.

Example 5

The 100% European Rapeseed Oil of Example 2 was blended with the additive and tested to determine the viscosity over a prolonged period of time at low temperatures. Likewise, the test was also performed on soybean oil-based dielectric fluids available from Copper Power Systems (Wikisha, Wis.) Under the trade name Envirotemp FR3 Fluid. The results are shown in FIG.

The results of FIG. 2 show that when introduced into electrical power equipment, substantially bio-based and biodegradable formulations of the dielectric fluid compositions described herein flow and maintain a relatively constant viscosity for a long period of time compared to conventional vegetable oils. Appeared.

In the above, various embodiments of the present invention have been described. These and other embodiments are within the scope of the appended claims.

Claims (21)

A composition comprising at least one vegetable oil and at least one antioxidant, wherein the composition has a pour point of less than about −20 ° C. and the pour point is measured according to ASTM D97 or ASTM D5950. The composition of claim 1, wherein the vegetable oil has a pour point of less than about −20 ° C. 3. The composition of claim 1, wherein the composition has a pour point of less than about −25 ° C. 4. The composition of claim 1, wherein the composition further comprises one or more pour point depressants and the composition has a pour point of less than about −30 ° C. 5. The composition of claim 4, wherein the composition has a pour point of less than about −33 ° C. 6. The composition of any one of claims 1 to 5, wherein the vegetable oil is rapeseed oil. 7. The composition of claim 6, wherein the rapeseed oil is one of Brassica Juneca , Brassica Campestris, and combinations thereof. Brassica june car, Brassica Kam paste-less, and one or more selected from a combination of rapeseed oil, and Synthetic ester Dielectric fluid composition comprising a. The dielectric fluid composition of claim 8, wherein the vegetable oil has a pour point of less than about −20 ° C., as measured according to one or more of ASTM D97 and ASTM D5950. 10. The dielectric fluid composition of claim 8 or 9, wherein the composition comprises at least 30% to at least 72.5% of rapeseed oil. The dielectric fluid composition of any one of claims 8 to 10, wherein the synthetic ester is a bio-based material as defined in USDA FB4P (2002 Farm Bill). The soybean, sunflower, crambe, corn, olive, cotton, safflower, vernonia, squerella and combinations thereof. The dielectric fluid composition further comprising one or more additional vegetable oils selected from one or more of. The dielectric fluid composition of claim 12, wherein the at least one additional vegetable oil is sunflower oil. The dielectric fluid composition of claim 8, further comprising one or more of a pour point depressant and an antioxidant. The dielectric fluid composition of claim 8, wherein the dielectric fluid composition is biodegradable as measured by method OECD 301. 16. The dielectric fluid composition of any one of claims 8-15, wherein the dielectric fluid composition is substantially free of genetically modified material. An electrical device having therein the dielectric fluid composition according to any one of claims 1 to 16. 18. The electrical device of claim 17 wherein the device is a transformer. As a method of producing a dielectric fluid, Providing one or more refined, bleached and deodorized rapeseed oils having a pour point of less than about -20 ° C. as measured by one or more of ASTM D97 and ASTM D5950, Treating rapeseed oil with clay, and Filtering rapeseed oil to produce treated rapeseed oil Manufacturing method comprising a. The method of claim 19, further comprising blending rapeseed oil with one or more antioxidant compounds and a pour point depressant. 21. The method of claim 19 or 20, further comprising blending the treated rapeseed oil with less than about 70 weight percent of one or more synthetic esters.

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