JPS6052532B2 - Method for manufacturing capacitor oil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing condenser oil using a heavy oil fraction produced as a by-product during a reforming reaction of hydrocarbon oil as a raw material.
More specifically, it has a high corona generation voltage and specific dispersion (25°C) obtained by processing such raw material oil.
2 circles or more, dielectric breakdown voltage 80KV/2.5m or more, dielectric constant (580℃) 2.5 or more, hydrogen gas absorption (8KV) 5
The present invention relates to a method for producing a condenser oil to obtain a new condenser oil having the following properties: (absorption amount) -15-oil at 0°C for 50 to 150 minutes.

Conventionally, many condenser oils have been used, such as those based on polychlorinated biphenyls, silicone oils, and mineral oils.

Among them, polychlorinated biphenyls have good electrical properties and have been widely used as capacitor oils.
It is no longer used because it is extremely toxic to the human body and causes pollution problems. Also, silicone oil
Because it is expensive, it is used only for special purposes. Currently, condenser oils based on mineral oils are most widely used. Mineral oil-based condenser oil is generally produced by distilling naphthenic crude oil, collecting a fraction suitable as condenser oil, and combining methods such as solvent refining, sulfuric acid washing, hydrogenation treatment, and clay treatment to obtain polycyclic aromatic components, Manufactured by removing sulfur, nitrogen, etc. However, the mineral oil-based capacitor oil thus obtained has drawbacks such as a small specific dispersion, a low dielectric breakdown voltage, a low dielectric constant, a low corona generation voltage, and a low hydrogen gas absorption property.
At present, the use of mineral oil-based condenser oils has to be restricted due to the above-mentioned drawbacks, as the usage conditions for condensers have become harsher due to the rapid increase in power demand and there is a need for equipment to be smaller and lighter. First, there was a need for a condenser oil with excellent properties.

The inventors of the present invention have made efforts to improve the above points, and as a result, compared to conventional capacitor oils, the dielectric breakdown voltage is higher, the corona generation voltage is higher, the specific dispersion is larger, the dielectric constant is larger, and the hydrogen gas absorption property is higher. The present invention was completed by developing a condenser oil that has high fluidity at low temperatures, good oxidation stability, and almost no toxicity.

The method for producing condenser oil of the present invention has a boiling point of 40 to 20
Hydrocarbon oil in the temperature range of 0°C is subjected to a reforming reaction under hydrogen pressure and in the presence of a reforming catalyst to produce aromatic hydrocarbons such as high octane gasoline, benzene, toluene, or xylene. Among the heavy oil fractions obtained as by-products, a specific fraction containing 8% or more by weight of those having a boiling point in the temperature range of 230 to 450°C (converted to normal pressure) is used as the raw material oil.

This heavy oil fraction has a poor hue and is unstable, and is insufficient as a capacitor oil in terms of electrical properties, heat resistance, oxidation stability, etc. The present invention is the first to discover that a capacitor oil with excellent electrical properties can be obtained by hydrorefining a specific fraction of these heavy oil fractions under specific conditions. Until now, most of the heavy oil fractions have been used as is as part of reformed gasoline, or only partially used as self-fuel or solvent.

Recently, research has been conducted on the use of this heavy oil fraction, and there are examples of its use in brushing alls, solvents, plastic working oils, etc. after alkylation with lower olefins. In addition, an example was reported in which castor oil, which is used as an electrical insulating oil, was improved by adding a heavy oil fraction alkylated with a lower olefin. However, it has not been put into practical use (Japanese Patent Laid-Open No. 49-38200). The purpose of the present invention is to obtain a heavy oil fraction with a boiling point (normal pressure equivalent) of 230 to 45C, which is produced as a by-product when a hydrocarbon oil is subjected to a reforming reaction using a reforming catalyst under hydrogen pressure.
A specific fraction containing 8...11% or more of substances in the temperature range of f'C is obtained by hydrorefining under specific conditions, and has a high dielectric breakdown voltage, a high corona generation voltage, and a high specific dispersion. It is an object of the present invention to provide a capacitor oil which has a large dielectric constant, a high hydrogen gas absorption property, and a large dielectric constant.

The hydrocarbon oil used in the reforming reaction in the present invention is
Those having a boiling point of 40 to 20 (range), preferably 60 to 18 (range), such as straight-run naphtha or cracked gasoline, are preferably used.

The reforming catalyst referred to in the present invention may be any catalyst that is normally used in this type of reforming reaction.

In particular, noble metal catalysts are preferably used. The noble metal catalyst preferably used in the present invention is one in which a platinum group element alone or a mixture of two or more is supported on a solid carrier. In addition, the present invention also includes a platinum group element or a mixture of two or more elements supported on a solid carrier in combination with one or more elements selected from Ge, Sn, Re, Fe, Pb, and halogen. Preferably used in the invention. Further, as the solid carrier, alumina, silica, zeolite, silica-alumina, etc. are suitable. The modification reaction in the present invention is carried out under the following conditions.
That is, the reaction pressure is 1 to 50k9/CltG, preferably 5 to 40kg/AiGl, and the reaction temperature is 400 to 600°C.
Preferably 470-530℃, hydrogen circulation amount is 1k1 of raw material
100 to 1,500 Nd of hydrogen, preferably 300 to
The supply speed (LHSV) of 1,000Nw11 oil is 0.5
~511r1 preferably 1~311r1. The present invention is directed to the heavy oil fraction produced as a by-product during the above-mentioned reforming reaction.
Boiling point (converted to normal pressure) 230 to 450°C, preferably 250°C
8% or more of substances in the temperature range of ~400℃,
Preferably, the fraction containing 9% or more by weight is further hydrorefined under specific conditions to obtain a capacitor oil with excellent electrical properties.

The heavy oil fraction does not need to be distilled as long as it satisfies the conditions for heavy reformed oil as defined in the present invention, but it is preferable to collect a fraction that satisfies the above conditions by distillation. This heavy oil fraction is a hydrocarbon having a carbon number of 10 or more, and most of it is a polycyclic aromatic hydrocarbon. The catalyst used in the hydrorefining of the present invention uses an inorganic solid such as bauxite, activated carbon, diatomaceous earth, zeolite, silica, alumina or silica-alumina as a carrier to oxidize Group 1B, Group or Group metals of the periodic table. It is supported in the form of a compound, a sulfide, a compound or a mixture of these.

Preferred Group 1B, Group 1 and Group 1 metals are cobalt, nickel, molybdenum, and tungsten.

In the present invention, a catalyst obtained by pre-sulfurizing a combination of two or more types of nickel oxide, cobalt oxide, molybdenum oxide, and tungsten oxide supported on an alumina carrier is particularly preferably used. The reaction temperature in the hydrorefining treatment is usually 230-400C, preferably 260-400C.
The temperature is 360°C. Below 230°C, the degree of purification is low and 40°C
When the temperature exceeds 0°C, side reactions such as decomposition and dehydrogenation occur, which adversely affects hue, electrical properties, etc.

The reaction pressure is usually 20-150k9/C7l! G is preferably 25 to 80k9/CIiG. Further, hydrogen is applied at a pressure of 100 to 10,000 Nd, preferably 200 to 1,000 Nd, per 1 kt of supplied heavy reformed oil. LHSV is 0.5-5
hr-1 preferably 1 to 4F1r1 is used. Hydrogenation precision in the present invention must be carried out under conditions that do not cause too much nuclear hydrogenation of aromatic compounds in the supplied oil. Therefore, as mentioned above, it is necessary to appropriately select the catalyst and reaction conditions. Further, the hydrotreated oil can be subsequently subjected to clay treatment if necessary. As described above, by hydrorefining a specific heavy oil fraction, the refractive index (20°C) is 1.5.
6-1.65. Dielectric breakdown voltage 80KV/2.5T! 0n
Above, hydrogen gas absorption (clear, 50℃, 50-15 powder absorption amount) - 150wrIn0I or less, specific dispersion (25℃) 2
A highly aromatic hydrocarbon having a molecular weight of 0.00 or more, particularly 220 to 240, is obtained and is used as a capacitor oil with excellent electrical properties.

As described in the examples below, the capacitor oil produced by the method of the present invention has a higher dielectric breakdown voltage and a higher corona generation voltage than mineral oil-based capacitor oils, so it can be used at high voltages. In addition, since the dielectric constant is extremely high, the device can be made smaller and lighter. Furthermore, it has a high flash point and extremely low pour point, so it has good low-temperature fluidity, little evaporation loss, low viscosity, good workability, excellent cooling effect, and extremely high JIS oxidation stability. It has excellent properties. In addition, its hydrogen gas absorption is significantly greater than that of mineral oil-based condenser oils, which is a major advantage in terms of prevention of corona generation, high-temperature use, and safety. Furthermore, compared to polychlorinated biphenyl, it has almost no toxicity to the human body and is superior in terms of pollution. The capacitor oil obtained according to the present invention may contain antioxidants and other additives when used. Furthermore, oils that have been used as capacitor oils such as mineral oil, silicone oil, hydrocarbon oil ( Polybutene, alkylbenzene, diallyl alkane, etc.), fluorocarbon compounds, etc., and hydrogenated refined oil of naphtha cracked heavy oil can also be used in combination. An oil-immersed condenser using the condenser oil obtained according to the present invention can have any structure,
It may be manufactured using any manufacturing method, and Ni is mainly used as the electrode material in the capacitor, but other materials such as Sn, Pb,
Ag etc. can be used.

Further, for one or both of these electrodes, a metal coating formed on the surface of a solid dielectric by a method such as vacuum evaporation or electron beam can also be used as the electrode. Further, as the solid dielectric material, kraft paper or synthetic resin film (polyethylene, polypropylene, polystyrene, polycarbonate, etc.) is used, and in order to improve the impregnation of the capacitor oil of the present invention into these solid dielectric materials, for example, It is also possible to use both kraft paper and synthetic resin film, or to use a synthetic resin film with a roughened surface or a synthetic resin film with fibrous substances attached to the surface. The content of the present invention will be described in more detail with reference to Examples below, but these are for illustration purposes only and the present invention is not limited thereto.

Example 1 Middle Eastern naphtha was treated with platinum-rhenium-chlorine-alumina catalyst (
PtO. 3wt%, ReO. 3 wt%, ClO. 6Wt
%) was introduced into the catalytic reformer from a multi-stage reaction tower filled with
CflGl hydrogen circulation amount is 300% per 1kt of naphtha supplied.
The reaction was carried out at a Nd3 and oil supply rate (LHSV) of 2 hr−1.

The obtained heavy oil fraction is distilled to a boiling point (converted to normal pressure) of 270
The ~36(1)C fraction was collected. This oil has a refractive index of Nd2Ol. 6238, viscosity (30°C) 8.789, C
%93.3sH%6.7, fractional properties are 20% distillation temperature 3
07C150% distillation temperature 317C190% distillation temperature 33
It was 9℃. Next, this fraction was presulfurized into nickel (3.0 wt% as NiO)-molybdenum (MOO3
(14 Wt%)-alumina catalyst was introduced into a flow-through reaction tube filled with alumina catalyst, and hydrorefined under the conditions of reaction pressure 50k9/CfiGl reaction temperature 320C1 liquid hourly space velocity (LHSV) 31r-1 and hydrogen 500N per 1kt of feedstock oil. I did this.

The obtained refined oil was treated with activated clay in three powders at 60°C under the conditions of 20k9 clay/kl oil. The properties of this oil are refractive index 1.589 and viscosity (3C)C) 7.840s (75℃)
2.376, pour point -50℃ or less, flash point 140C,.
According to the ndM ring analysis method, %CA6l. 8.%CN27.
O and %Cpll. It was 2. Also, the fractional property is 20
The % distillation temperature was 2°C, the 50% distillation temperature was 301°C, and the 90% distillation temperature was 323°C. Next, the general properties and electrical properties of this refined oil as a capacitor oil are shown in Table 1 in comparison with mineral oil-based capacitor oils.

Example 2 Boiling point (normal pressure equivalent) obtained in Example 1: 270-360°C
The heavy oil fraction of
Wt%)-alumina catalyst was introduced into a flow-through reaction tube and subjected to hydrorefining.

Purification conditions are reaction pressure 35k9/C7lfGl reaction temperature 3
The temperature was 40°C, liquid hourly space velocity (LHSV) 2F1r1, hydrogen circulation amount 500N/Kt, and one raw material. 20% of the obtained oil
A three-powder clay treatment was carried out with 6C)C under the conditions of K9 one clay/Kt one oil. Table 1 shows the properties of this refined oil as a condenser oil. Example 3 Iranian heavy naphtha was treated with platinum monochlorine-alumina catalyst (PtO.37wt%, ClO
．． The reaction pressure was 35k9/CiiGl, the reaction temperature was 490-515°C, and the liquid hourly space velocity was 0.9F1r-1.
The hydrogen circulation amount was 1,000 Nd per 1 kt of raw material.

The obtained heavy oil fraction was distilled under reduced pressure to a boiling point (converted to normal pressure) of 25
The 0-360C fraction was collected. The properties of this fraction are that the refractive index is 1.595 and the fractional properties are 20%, 50%, and 90%.
The distillation temperatures were 267, 286 and 347C, respectively. This fraction was then pre-sulfurized into Cobalt Tomori 7.
Den-alumina catalyst (3.2 Wt% as COO, M
The mixture was introduced into a flow reactor filled with 5.6 wt% (as OO3) and subjected to hydrorefining.

Purification conditions are reaction pressure 70 kg/CllGl reaction temperature 30
0℃, liquid space velocity 1.0F1r-1, hydrogen circulation amount 1.0
00N/Kt is one oil. The obtained oil was distilled under reduced pressure and a fraction with a boiling point (converted to normal pressure) of 252 to 3477C was collected.
This fraction was subjected to three clay treatments at 60° C. under the conditions of 20 kg of clay/kl of oil in accordance with a conventional method, and its properties were measured as a condenser oil. The results are shown in Table 1. Comparative Example 1 Boiling point obtained in Example 1 (converted to normal pressure) 270-360°C
2 heavy oil fractions without hydrorefining.
0! Three-powder activated clay treatment was carried out at 60° C. under the conditions of one Cg clay/one Kt oil.

The general properties and electrical properties of this oil were measured and shown in Table 1. This oil was not suitable as a condenser oil because it had not been subjected to hydrorefining treatment and had a low degree of refinement and particularly poor electrical properties. The detailed properties of this oil are shown in Table 1. Comparative Example 2 The properties of a commercially available mineral oil-based condenser oil were measured and are shown in Table 1.

As is clear from Table 1, the condenser oil of the present invention is
A comparison between the oil obtained in Comparative Example 1 and the commercially available mineral oil-based condenser oil in Comparative Example 2 reveals that the oil has significantly superior properties.

Claims (1)

[Claims] 1 Among the heavy oil fractions produced as by-products when a hydrocarbon oil is subjected to a reforming reaction in the presence of a reforming catalyst, those whose boiling point (in terms of normal pressure) is within the temperature range of 230 to 450 °C The distillate containing 80% by weight or more of
m^2・G, temperature 400-600℃, hydrogen circulation amount 100
~1500Nm^3/kl oil, LHSV0.5~5hr
Hydrorefining treatment under the conditions of ^4 and specific dispersion (25℃)
200 or more, dielectric breakdown voltage 80kV/2.5mm or more,
Dielectric constant [(a) 80°C] 2.5 or more and hydrogen gas absorption (8 kV, 50°C, absorption amount for 50 to 150 minutes) 150
A method for producing a condenser oil to obtain a condenser oil having characteristics equal to or less than that of mmoil.