JPS5966494A - Purification of waste oil of flon synthetic lubricant - Google Patents

Abstract

PURPOSE:To recover oil components free from impurities such as deteriorated substances, sludge, admixtures, etc. at all, by purifying coarsely a waste oil of flon synthetic lubricant, extracting it with petroleum ether. CONSTITUTION:Impurities are separated and removed from a waste oil of flon synthetic lubricant by centrifugation, column treatment, etc., 10pts.vol. oil components are stirred with >=2pts.vol. petroleum ether, allowed to stand, and separated into a petroleum ether oil phase and a liquid phase. The prepared colorless transparent liquid phase is evaporated under reduced pressure so that the volatile petroleum ether is removed, to give the desired purified oil.

Description

Detailed Description of the Invention The present invention relates to perfluoropolyethers, which are used in fields where properties such as heat resistance and oxidation resistance stability are particularly required.
This invention relates to a method for producing waste oil of fluorocarbon-based synthetic lubricating oil such as perfluoropolyphenyl ether or perfluoropolyether triazine.

As is well known, fluorocarbon-based synthetic lubricants are chemically extremely stable, have excellent heat resistance, and are nonflammable compared to various synthetic lubricants other than fluorocarbon-based synthetic lubricants and mineral oil-based lubricants. In addition to their basic properties, there are also notable differences in membrane properties. In other words, the specific gravity is about twice as heavy (for example, perfluoropolyether has a specific gravity of about 1.9 at 20°C, while mineral oil has a specific gravity of about 0°9), and most solvents except fluorine-based solvents They almost never dissolve in each other. Furthermore, it is virtually immiscible with water, animal and vegetable oils, mineral oils, and other synthetic lubricating oils. Moreover, it has unique properties such as not mixing or reacting with mineral acids such as sulfuric acid and nitric acid.

In this way, fluorocarbon-based synthetic lubricants have excellent heat resistance and oxidation stability, are chemically stable against various metals and do not corrode, and have chemical reactions with various gases and liquids. It has unique properties such as not causing any problems and hardly mixing with liquids, and its performance as a lubricating oil is comparable to that of many other lubricating oils. Because of these distinctive properties, fluorocarbon-based synthetic lubricants are ideal for use in areas that require heat resistance and oxidation stability, or where stable lubrication performance over a long period of time is required. be. For this reason, fluorocarbon-based synthetic lubricating oils are often used as lubricating oils for vacuum pumps, for example, to create vacuum systems required in the electronics industry.

However, the lubricating oil used in this vacuum pump is fluorocarbon-based synthetic 11! l Even lubricating oil can become contaminated and deteriorate due to contamination with various substances discharged from the system to be exhausted, abrasion particles from the friction and wear of the vacuum pump, and deterioration of the fluorocarbon-based synthetic lubricant itself. Even lubricating oils with excellent stability end up becoming waste oil.

CFC-based synthetic lubricating oils are also used to lubricate vacuum pumps, bearings, gears, etc. of various equipment, but in any case, they end up becoming waste oil after use.

As mentioned above, fluorocarbon-based synthetic WJ lubricating oil is chemically stable and nonflammable, so waste oil from fluorocarbon-based synthetic lubricating oil cannot be disposed of by incineration or thermally decomposed. Moreover, since it cannot be decomposed by microorganisms existing in the natural world, it cannot be disposed of, and therefore, the disposal of this fluorocarbon-based synthetic lubricating oil has become a major social problem.

The present invention is a method for refining waste oil of fluorocarbon-based synthetic lubricating oil, which has been devised in view of the above points, and its purpose is to recover oil that does not contain any impurities such as deterioration products, slatch, and contaminants. The gist of this is that the waste oil is centrifuged or passed through a column packed with fibrous material for the first stage of crude purification, and then 2 parts of petroleum ether is added to 10 parts by volume of the crude oil obtained. After adding more than 1 part by volume and stirring, a second stage of petroleum ether treatment is performed to separate the upper petroleum ether phase and the lower colorless and transparent oil phase, and then the colorless and transparent oil phase is collected. The present invention provides a method for refining waste fluorocarbon-based synthetic lubricating oil, which comprises removing petroleum ether from the oil phase.

−4= The present invention will be explained in detail below.

In the first embodiment, in the first stage of the method for refining waste oil of fluorocarbon-based synthetic lubricating oil, the waste oil is roughly purified by centrifugation. Since the main purpose of the centrifugation operation is to remove substances floating in the oil phase of waste oil, the centrifugal effect is preferably Z-1500 or higher. As is well known, fluorocarbon-based synthetic lubricating oil does not mix with mineral oil or most other substances, and has a very high specific gravity, so a considerable amount of impurities can be separated and removed from waste oil even if it is allowed to stand still. can do.

However, it is impractical to let waste oil stand still and separate it into fluorocarbon-based synthetic lubricating oil in the lower phase and contaminants in the upper phase because it requires a long period of standing, and it is not practical to separate waste oil into the contaminants in the upper phase by actively centrifuging the oil. It is better to separate the oil and the lower phase of fluorocarbon-based synthetic lubricating oil. The oil obtained by this centrifugation is purified to a nearly milky, translucent color. When waste oil contamination is particularly severe, some suspended solids with a blackish brown color may still be observed in the resulting oil. In this case, it is sufficient to perform a centrifugal separation operation that increases the centrifugal effect, and through this rough refining, a purified CFC-based synthetic lubricating oil with a milky white translucent color in which no black-brown suspended substances are visible in the oil in the lower phase can be obtained. obtain.

As the second stage of waste oil refining, petroleum ether treatment is performed in which petroleum ether is added to the crude oil obtained by centrifugation in the first stage, stirred and mixed, and left to stand.

That is, the oil obtained by performing the first stage rough refining treatment is a milky white translucent liquid or a transparent liquid in which the presence of a slight white suspended substance is recognized. Add 2 parts by volume or more of petroleum ether to 10 parts by volume of this oil and mix thoroughly with stirring. After that, when the mixture is allowed to stand still, the oil component moves to the lower phase and the petroleum ether moves to the upper phase, and the mixture is separated into two phases. A part of the milky white suspended solids present in the oil is dissolved and transferred to the petroleum ether phase, and the rest exists as a thin film of suspended solids at the boundary between the two phases. Therefore, the oil component in the lower phase is completely colorless and transparent.

In this petroleum ether treatment, if the amount of petroleum ether added to the oil is small, the entire amount will be dissolved in the oil and the oil will be -
Two-phase separation of petroleum ether does not occur, and therefore suspended solids present in the oil are not removed.

In order to cause two-phase separation and to remove suspended solids, 2 parts by volume or more of petroleum ether is required per 10 parts by volume of oil, preferably 10 parts by volume of petroleum ether.

In addition, when the temperature of the oil is low, the viscosity increases significantly when the oil is left to stand after petroleum ether treatment, and it takes more time than necessary to completely separate the two phases, and some of the petroleum ether dissolved in the oil becomes cloudy. condition, which may prevent complete clarification. For this reason, the oil temperature when left to stand is preferably 20°C or higher, preferably 25°C.
That's all.

In place of the above petroleum ether, petroleum benzine or globin, which are of the same hydrocarbon series, or trichloroethylene (triclene), which has excellent dissolving power for many organic substances, can be used.
Even if the oil is purified using chloroform, acetone, methyl ethyl ketone, methyl acetate, n-hexane, benzene, toluene, or other organic solvents, the oil may become cloudy.
It exhibited a white hazy state, and this cloudy state could not be easily eliminated by ordinary methods. Although the reason for this is unknown, an oil that became completely colorless and transparent was obtained only when treated with petroleum ether.

Next, as the third stage of waste oil refining, petroleum ether removal treatment is performed. That is, the completely colorless and transparent oil obtained by the petroleum ether treatment is collected in a distillation apparatus to remove petroleum ether. This petroleum ether removal does not have to be carried out using a particularly limited method to obtain good results, and can be easily carried out using a conventional vacuum distillation apparatus.

The oil obtained as described above is a viscous liquid that is completely colorless and transparent in appearance, and no impurities were detected by component analysis using infrared spectroscopy, and it is indistinguishable from new oil. A completely matched spectrum diagram was shown. Furthermore, regarding the general properties and performance test results as lubricating oil, it was found that the oil obtained from waste oil by the refining method of the present invention had the same properties and performance as new oil. .

EXAMPLES The first embodiment of the present invention will be specifically described below with reference to Examples.

Example 1 Waste oil of fluorocarbon-based synthetic lubricating oil used in a vacuum pump for creating a vacuum system required in the electronics industry was collected in a separatory funnel and allowed to stand at room temperature for 2 days. Incidentally, the amount of contaminants in this waste oil is approximately 0.3% by weight, and the amount of ash in the contaminants is 0.3% by weight.
The content was 1% by weight or less, and the appearance was a liquid with blackish brown viscosity. After standing still, collect the oil in the lower phase into a centrifuge tube,
When centrifuged under the conditions of centrifugal effect Z-2000 for 10 minutes, a dark brown substance was precipitated in the upper phase, and a milky white translucent oil was obtained in the lower phase. 178g of this oil
The mixture was transferred to a 1,200 ml squib-type separating funnel, and 100 ml of petroleum ether (volume ratio of oil to petroleum ether: about 10 parts by volume: about 10 parts by volume) was added, thoroughly stirred and mixed, and left to stand still. When the mixture was allowed to stand at 10-room temperature for a day and night, it was completely separated into a petroleum ether phase in the upper phase and an oil component in the lower phase, and the presence of impurities in the form of a white thin film was observed at the boundary between the two phases. Ta. The oil in the lower phase was completely colorless and transparent, and it was transferred to 2001 and a vacuum dryer heated to 70°C to completely remove petroleum ether. The amount of oil obtained was 176 g. Table 1 compares the property analysis values of this oil (recycled oil) with those of new oil.
It was shown to. Also shown in the figure is a diagram of the temperature-viscosity relationship between recycled oil and new oil.

From the results shown in Table 1 and the figures, it can be seen that the recycled oil obtained by the present invention has almost the same properties as the new oil.

In the second embodiment, in the first embodiment described above, the method of separating and removing impurities from the waste oil in the first stage is to perform centrifugation by taking advantage of the property that the specific gravity of fluorocarbon-based synthetic lubricating oil is extremely high. As explained above, the method for separating and removing impurities from the waste oil in the first stage in the second embodiment is based on a method in which the surface tension, which is one of the other characteristics of fluorocarbon-based synthetic lubricating oil, is about 20 dyn/
This can also be done by taking advantage of the property that co+ is extremely small. That is, the waste oil may be passed through a column filled with fibrous material to separate and remove impurities. The fibrous material that can be used here is not particularly limited, and may be not only absorbent cotton but also ordinary cloth, for example, recycled cloth commonly used for cleaning, such as waste cloth. Further, the same effect can be obtained even with a paper-like material having a high porosity, such as a paper-like paper. The oil obtained by passing the waste oil through this column packed with fibrous material is a slightly cloudy, transparent liquid. Although the speed of waste oil cleaning is somewhat slower than the previous centrifugal separation method, the degree of cleaning is far superior. Generally speaking, the filtration process for mineral oil-based waste oil and the like decreases rapidly, but in the case of fluorocarbon-based synthetic lubricating oil, such a decrease is not observed, and the oil is purified at a nearly constant purification rate from beginning to end.

Therefore, it is not necessary to apply pressure in particular, and a natural flow may be used, but in some cases, the cleaning speed can be increased by applying some pressure.

-]]- Furthermore, the waste oil treated in this packed column has a characteristic that the oil obtained has a higher degree of cleanliness when the degree of contamination due to contaminants is somewhat greater.

This is because the dark brown oil present in the waste oil is I! Fibrous substances adhere and are fixed there, but as mentioned above, CFC-based synthetic lubricants do not mix well with fibrous substances due to their extremely low surface tension, and they also naturally do not mix well with dark brown oils. Since they do not mix together, it is presumed that they are separated at this stage. Furthermore, since the black-brown oil is a viscous substance, it has the property of incorporating impurities other than fluorocarbon-based synthetic lubricating oil into it. It is thought that this results in good effects being obtained.

The second embodiment of the present invention will be specifically described below with reference to Examples.

Example 2 A fluorocarbon-based synthetic lubricating oil obtained from a vacuum pump at a factory different from that in Example 1 had an amount of impurities of 1.61% by weight and 12% by weight, and an ash content in the impurities of 0.85% by weight. It was a highly contaminated dark brown viscous liquid. This waste oil was allowed to stand overnight in a separatory funnel, and the oil in the lower phase was passed through a glass tube column (inner diameter 13 ev, rag packing thickness 50 mm) for the first stage of purification. The obtained oil was a clear liquid with a slight milky white floating substance.

When this oil was treated with petroleum ether in the same manner as in Example 1, a recycled oil was obtained which was completely colorless and transparent and had almost the same properties as the new oil. The property analysis values of this oil (regenerated oil) are shown in Table 2 in comparison with the values of new oil.

The operating temperature for both centrifugation and fibrous substance packed columns is not particularly limited; however, at low concentrations, the viscosity of the oil increases and the centrifugation effect deteriorates, or the temperature required to pass through the column increases. Since the time may become longer than necessary, the temperature is preferably room temperature or higher. In addition, as the second stage petroleum ether treatment, 2 parts by volume or more of petroleum ether is added to 10 parts by volume of the oil from which impurities have been separated and removed in the first stage, and after stirring and mixing,
4- Table 1 Comparison of properties of recycled oil and new oil Table 2 Comparison of properties of recycled oil and new oil *1 Rotation speed 200 rpm! 11, Display KO/c1*2
Rotation speed 1500rl)m, load 50Ko, time 30 minutes,
It was explained that the display should be left for 1 m, but even if 2 parts by volume or more of petroleum ether were added to 10 parts by volume of oil, and the mixture was stirred and centrifuged, the oil would remain in the lower phase as explained in each of the above embodiments. Then, petroleum ether migrates to the upper phase and separates into two phases.

[Brief explanation of drawings]

The drawing is a graph showing the relationship between temperature and viscosity of recycled oil and new oil obtained by the method for refining waste oil of fluorocarbon-based synthetic lubricating oil according to the present invention. Patent applicant Kanagawa Prefecture
1. Agent Patent attorney Isao Sasaki′□゛□゛；′
) 1, 8゛1-' 15- Story Leprosy 16- Procedural amendment layer (voluntary) November 12, 1980 Commissioner of the Japan Patent Office Kazuo Wakasugi 1, Indication of the case 1988 Patent Application No. 176368 2 , Name of the invention Method for refining waste oil of fluorocarbon-based synthetic lubricating oil 3, Relationship to the case of the person making the amendment Patent applicant address 1 Nihon Odori, Naka-ku, Yokohama Name
Kanagawa Prefectural Governor Long Tan-24, Agent 105 Address 1-11-7-1 Toranomon, Minato-ku, Tokyo -
1.25. Subject of correction
-''-' Each column of "Detailed Description of the Invention" and "Brief Description of Drawings" in the manifest. 6. Details of correction [1] "Moisture content - viscosity" on page 11, line 9 of the specification is corrected to "viscosity - temperature". C) "About 206yn/cmJ" in the first line of page 12 of the same book
"About 20 dyne/c#l" (!: Correct.) (3) Tables 1 and 2 on page 15 of Doshuun are revised as shown in the attached sheet. (4) Lines 8 to 3 of page 16 of page iii of the same Correct the [Relationship between temperature and viscosity of new oil] in line 9 to "Relationship between viscosity and temperature of new oil." 2- Table 1 Comparison of properties of recycled oil and new oil Table 2 Comparison of properties of recycled oil and new oil Comparison of properties

Claims (1)

[Scope of Claims] (1) A rough refining step of separating and removing impurities from waste oil of fluorocarbon-based synthetic lubricating oil to obtain an oil component, and adding 2 volumes of petroleum ether to 10 parts by volume of oil obtained by this rough refining step. A petroleum ether treatment step in which the oil is stirred and separated into a petroleum ether phase and an oil phase, and a volatile component of petroleum ether is separated from the colorless and transparent oil phase obtained by this petroleum ether treatment step. A method for refining waste oil of fluorocarbon-based synthetic lubricating oil, characterized by comprising an ether removal step. (2) A method for refining waste oil of fluorocarbon-based synthetic lubricating oil according to claim (1), characterized in that a centrifugal separation operation is performed in order to separate impurities from the waste oil as the crude II production step. (3) The synthetic lubricant according to claim 1, wherein the waste oil is passed through a column filled with #AH-like substances in order to separate impurities from the waste oil as a rough refining step. Method for refining waste oil. (4) In the petroleum ether treatment process, the petroleum ether phase and oil phase are separated by adding 2 parts of petroleum ether to 10 parts by volume of oil.
The fluorocarbon-based synthesis fl! according to claim (1), characterized in that the fluorocarbon-based synthesis fl! is carried out by adding at least part by volume, stirring, and then allowing the mixture to stand still. l A method for refining waste lubricating oil. ■ Separation of the petroleum ether phase and oil phase in the petroleum ether treatment process is performed by adding 2 parts by volume or more of petroleum ether to 10 parts by volume of oil, stirring, and centrifuging. A method for refining waste fluorocarbon-based synthetic lubricating oil as described in (1).