DE2049050C2 - Insulating oils - Google Patents

Description

The invention relates to insulating oils, which are made from mineral oils by catalytic hydrogenation and treatment with contain oils obtained from a solid adsorbent.

Apart from the pour point, flash point and viscosity requirements Insulating oils, e.g. B. used in transformers, electrical switches, hollow cables or capacitors have good electrical properties, such as a low dielectric loss factor or a high resistance of this loss factor and good resistance to oxidation, for example a low one Tendency towards acid and sludge formation.

In some cases, insulating oils should also have good gas absorption properties. Because these properties the higher the aromatic content, such oils should have a high aromatic content exhibit. The required aromatic content depends, among other things, on the type of aromatic contained in the oil Connections and the test method used.

In some cases, bolier oils are used as oxidation inhibitors to improve their resistance to oxidation Added because the sensitivity of an insulating oil to oxidation inhibitors with decreasing aromatic content If this oil is higher, it can then be advantageous if the insulating oils have a low aromatic content exhibit.

The object of the invention was therefore to provide insulating oils with the desired properties in as variable a manner as possible regarding the ability to absorb gases or a high sensitivity to oxidation inhibitors to provide.

This object is achieved according to the invention

The invention thus relates to insulating oils, which are made from mineral oils by catalytic hydrogenation and Treatment with a solid adsorbent obtained oils and optionally oil components with lower Aromatic content as the hydrotreated oils and are characterized in that the Insulating oils

a) 40 to 99.4 percent by weight of a naphthenic or paraffin-based mineral oil by catalytic Hydrogenation and treatment with concentrated sulfuric acid or oleum and with a solid adsorbent obtained oil (Ol A), so

b) 0 to 40 percent by weight of a naphthenic or paraffin-based mineral oil which has an aromatic content has below 20 percent by weight, which is also lower than oil A (oil B),

c) O ^ to 20 percent by weight of a mineral oil which has an aromatic content above 40 percent by weight has, which is also higher than with oil A and / or the mixture of oil A and oil B (oil C), and possibly

d) low levels of an oxidation inhibitor

exist.

According to the invention, the new insulating oils are composed of two must-oil components, namely the eo oil A and oil C, and optionally an oil component B can also be used.

The oil component A is an oil that has been subjected to a three-stage pretreatment is, namely a catalytic hydrogenation, a sulfuric acid or oleum treatment and a treatment with a solid adsorbent.

As the comparative oil I * of the following Table III of the working example confirms, no good ones are obtained Properties related to the gas absorption capacity, the dielectric loss factor and the oxidation resistance obtained when the oil component A is not mixed with concentrated sulfuric acid after the hydrogenation and has been treated with fuller's earth.

Must oil component C is a product with a comparatively high aromatic content from over 40 to z. B. to 90 percent by weight (see. Table II of the embodiment).

In contrast, the optional oil component B must have an aromatic content below 20 percent by weight, and this must also be smaller than that of component A.

In a two-component system, the oil A could therefore have an aromatic content O in one In the three-component system, however, the lower permissible aromatic content is based on the aromatic content the used component B.

Of the 13 insulating oils according to the invention listed in Table HI of the example, the oils! up to X such two-component systems. Examples XI, XII and XUI, however, explain mixtures that are soft ίο also contain the oil component B.

All of the insulating oils of the present invention show excellent dielectric properties Loss factor, resistance to oxidation and the ability to absorb gas, so the technique through this Insulating oils is clearly enriched.

From the state of the art, there are no correspondingly composed insulating oils with comparable ones favorable properties known

According to DD-PS 27 654, the production of insulating oils must be made from a naphthenic distillate fraction with certain properties can be assumed, and this distillate fraction then undergoes a sulfuric acid treatment and subjected to treatment with a solid adsorbent. A hydrogenation of this The parliamentary group, however, is not envisaged.

It is obvious that here the possibilities of variation with regard to the starting material are very great are limited, so that this production method does not meet the practical requirements.

FR-PS 13 38 529 provides for the oxidation stability of insulating oils by adding special To increase alkylnaphthalenes, which contain a group with a quaternary C atom in the alkyl substituent. These special alkylnaphthalenes must be prepared separately, e.g. B. by attaching the relevant

the alkyl substituents on naphthalene. The base oil will! by treating light distillates from Tia

Obtained juane crude oil with phenol and subsequent hydrogenation. The data in the tables on pages 3 and 4

show, however, that the dielectric loss factors are relatively large. You can also use this pre-release therefore no insulating oils are taken according to the teaching of the invention. In particular, it is according to the invention

nor is it necessary to use a solvent-refined distillate as the starting material.

According to the teaching of GB-PS 9 46 540 one should use an acid-refined base oil with a total aromatic content

Mix less than 5 percent by weight with another insulating oil to increase the content of

Naphthenes and to reduce the content of polygonal aromatics has been treated, with the Mixture should have the lowest possible aromatic content in the range from 11 to 14 percent by weight Neither of the two oil components of the GB-PS is more catalytic! Subjected to hydrogenation treatment but for

a standard treatment is applied to the base oil, which includes the level of sulfuric acid refinaiion and the

Adsorbent contacting step

In comparison to this prior art, the total aromatic content of the oils according to the invention (cf. oils I to XIII from Table III of the exemplary embodiment) with 20 to 40 percent by weight significantly higher.

The two British patents 8 96 066 provide for certain additives to be incorporated into the insulating oils, namely special selc-alkyl-substituted aromatic compounds or special ring-substituted; Aromatics with one or more tert-substituents.

However, both references give no indications or suggestions that the relevant Insulating oils themselves are made up of certain oil components, a must.

The US-PS 26 72 448 only deals with the type of antioxidant to be added and

writes certain synergistic combinations of alkylphenols and dihydroxyanthraquinones.

With regard to the base insulating oil, this reference does not contain any information as to whether this has any influence at all

exercises. A certain composition is neither prescribed nor will the base insulating oil be used

\ ι · Ι. lir π Uiiliiil

In IN-PS b7 8/2 it is proposed to use the usual sequence of i ».hwe [clsaurc (oleum) -Ra [finuti <jn and To replace the bleaching earth treatment with another method in which one uses a hydrogenation treatment a contact with solid absorbent combined.

However, the comparative oil I * in the exemplary embodiment below shows that when a

such oil component (base oil A *) no favorable results can be achieved. In addition, from the

IN-PS also does not deduce that the oil components treated with hydrogenation are treated with at least one

Ren oil component (oil C according to the invention) must be blended. Rather, it is merely optional

proposed to add an oil component B with a lower aromatic content.

This optional component B is optionally a treatment with concentrated sulfuric acid and a Subjected to contact with a solid adsorbent.

Since the insulating oils according to the invention either have a relatively low or a high aromatic content bo, they can either have good electrical properties and gluer oxidation resistance excellent gas absorption properties or an excellent sensitivity to oxidation inhibitors exhibit. The insulating oils of the invention are of particular importance as gas-absorbing insulating oils.

Mineral oils which are suitable for the production of oil A are, for. B. naphthenic or paraffinic distillates. Preferred are mineral oils having a viscosity (20 ⁰ C) of 10 to 100 MMCs, in particular 15 to 50 mm ² / s. The catalytic hydrogenation of these oils is preferably conducted at temperatures of 250 to 425 ° C, in particular 300 to 400 ⁰ C, pressures of 10 to 200 kg / cm ^2, in particular 25 to 150 kg / cm ² of a gas discharge amount of 50 to 5000 liters / kg Oil, in particular 100 to 500 liters / kg QiI, and with an oil flow rate of 03 to 3 kg / liter catalyst · h, in particular 0.5 to 2 kg / Lil: er catalyst · h. As catalysts

the oxides and sulfides of metals of the VI are suitable for this hydrogenation. and VlU. Group of periodic Systems, such as the oxides and / or sulfides of cobalt and / or molybdenum and / or tungsten and / or nickel. The catalysts are preferably applied to supports, such as activated carbon. Fuller's earth, kieselguhr, silicon dioxide or alumina. Very suitable catalysts consist of nickel or cobalt sulphide and Molybdenum sulfide on an alumina support.

Used to improve the oxidation resistance and electrical properties of the oil The sulfur contained in the oil and derived from the sulfur compounds is converted into catalytic hydrogenation Separated form of hydrogen sulfide The catalytic hydrogenation of the oil is preferably carried out in a carried out in such a way that more than 50 percent by weight, in particular more than 85 percent by weight, of the sulfur contained therein can be removed. Some of the hydrogen sulfide formed remains in the oil, and It is important that this part is removed from the oils before further treatment. This separation of hydrogen sulfide can be achieved, for example, by stripping the oil with an inert gas.

Insulating oils often have to have a flash point that is not below a certain temperature. The catalytic hydrogenation lowers the onset of boiling by a certain amount. This lowers the ramming point of the oil.This has the consequence that the flash point of the finished insulating oil does not meet the relevant requirement.If this is the case, the low-boiling compounds should be separated from the oil, for example in a simple manner by distillation. This distillation is carried out until the residue has the desired flash point. The separation of the low-boiling compounds is preferably carried out before the treatment of the oil with concentrated sulfuric acid or Hi Oieum

The acid treatment can be carried out very conveniently with concentrated sulfuric acid (80 to 100%) or oleum (up to 30% dissolved SOa), proportions of 0.5 to 30 percent by weight, preferably 1 to 15 percent by weight, based on the treated oil, are used and with temperatures of 0 to 75 ° C and a treatment time of 5 seconds to 1 hour. The refining can be carried out in one or more stages and either batchwise or continuously. In the case of discontinuous refining, the treatment temperature is preferably about 25 ^° C., in the case of continuous refining it is preferably about 60 ^s C. After the treatment with concentrated sulfuric acid or oleum, the acid sludge formed is separated from the oil

Then the oil, which still contains residual acid or sulphonic acids formed during acid treatment may contain, treat with a base for neutralization, such as aqueous or alcoholic sodium hydroxide solution. the The base used in each case is then separated off from the oil and the oil is then washed, for example with water and / or an alcohol such as ethanol. Instead of the "wet" treatment described above A "dry" treatment with an excess of a solid neutralizing agent can also be used to neutralize the oil. such as calcium oxide.

Finally, the oil is treated with a solid adsorbent, such as an absorbent earth or a corresponding clay. Examples of suitable adsorbents are fuller's earth. Bauxide and optionally acid-activated clays. z. B. a certain commercially available bleaching earth with a bulk weight: before. about 560 g / uter. During the aforementioned treatment, the oil is optionally heated and flushed with an inert gas such as nitrogen. The amount of adsorbent used is preferably 0.5 to 30 percent by weight, in particular 1 to 5 percent by weight, in each case based on the treated oil

Just like the catalytic hydrogenation, the treatment with concentrated sulfuric acid or serve Oleum and treatment with a solid adsorbent to improve resistance to oxidation and electrical properties of the oil.

Mineral oils, which are suitable as oil B, should have a lower aromatic content than oil A, namely an aromatic content of less than 20 percent by weight. The aromatic content mentioned here is always by percolating the oil over silica gel according to that in "Journal of the Institute of Petroleum" 36 (1950) The method described on pages 89 to 104 is determined. The sulfur content of the oil B is preferably less than 1 percent by weight, in particular less than 3 percent by weight

Examples of oils suitable as oils B according to the invention are:

1) naphthenic and paraffinic distillates,

2) basic naphthenic and paraffinic distillates, which are produced in a manner known per se by means of a selective Solvent for the aromatic components of the oil, such as liquid sulfur dioxide or furfural, were extracted;

3) basic naphthenic and paraffinic distillates, which are among those described for the manufacture of oil A. Conditions were catalytically hydrogenated;

4) basic naphthenic and paraffinic distillates, which are both catalytically hydrogenated and with a solvents selective to the aromatic components of the oil have been extracted (the The order of these refining stages is arbitrary);

and

5) Mineral oils according to 1) to 4), which a post-treatment with a solid adsorbent or with concentrated sulfuric acid or oleum and with a solid adsorbent among those in the Preparation of the oil A were subjected to the conditions described.

For the production of the insulating oils according to the invention, preferred oils B are those from a naphthenic base or paraffinic distillate were obtained by a refining process in which a catalytic hydrogenation and / or extraction with a selective solvent for the aromatic components of the oil, possibly in combination with other refining treatments, such as a treatment

with a solid adsorbent or treatment with concentrated sulfuric acid or oleum and with a solid adsorbent. Oils B with a viscosity (20 ° C.) of 10 to 40 mm ² / s are also preferred.

Examples of oils C which are suitable for obtaining the insulating oils according to the invention are: 5

1) naphthenic and paraffinic distillates:

2) aromatic extracts obtained from a naphthenic or paraffinic distillate by extraction obtained with a solvent selective to the aromatic components of the oil became;

io and

3) Mineral oils according to 1) and 2), which a post-treatment with a solid adsorbent or with concentrated sulfuric acid or oleum and with a solid adsorbent among those in the Preparation of the oil A were subjected to the conditions described.

Oils C with an aromatic content above 40 percent by weight and a sulfur content above OJ percent by weight are preferred.

To obtain the insulating oils according to the invention, oils A, B and C can first be refined and separately are then mixed with one another in the desired proportion. However, if for the If you need to produce more than one base oil at the same refining level, you can use the components as well mix first and then subject the resulting mixture to the relevant refining stage.

This option can be used, for example, when the production of oil B

and / or the oil C a treatment with a solid adsorbent or with concentrated sulfuric acid

or oleum and with a solid adsorbent.

When using paraffin-based components for the production of the insulating oils of the invention can

oils with a pour point that is too high can be obtained. In such a case, dewaxing must be carried out either on the paraffin-based base oil or, after mixing, on the insulating oil itself The latter method is preferred if the insulating oil is obtained from two or three paraffinic base oils will. Since the use of paraffin-based base oils for the production of oils A, B and C is an additional factor Requires refining stage, naphthenic base oils are preferred for this purpose

In view of the requirements for insulating with respect to the pour point, flash point and viscosity have the insulating oils of the invention preferably a pour point below - 10 ⁰ C, in particular below -30 ⁰ C, a flash point above 100 ⁰ C, in particular above 130 ⁰ C, and a viscosity (20 ^° C.) of 10 to 70 mm ² / s, in particular 10 to 45 mm ² / s.
The insulating oils of the invention are of particular importance for use in transformers.

Insulating oils according to the invention, which the aforementioned components A, C and optionally B in the Contain the aforementioned proportions, generally have good electrical properties and good resistance to oxidation on. However, preference is given to insulating oils which are either 90 to 99.5 percent by weight oil A and 03 to 10 percent by weight of oil C, in particular 95 to 984 percent by weight of oil A and 1.5 to 5 percent by weight from oil C or from 50 to 893 percent by weight from oil A, from 10 to 40 percent by weight

oil B and from 03 to 10 percent by weight of oil C, in particular from 55 to 833 percent by weight of oil A, to 15 to 40 percent by weight of oil B and 13 to 5 percent by weight of oil C consist.

If the insulating oils according to the invention only consist of an oil A and an oil C, they can be very cheap Results are achieved when the oil A was made from a naphthenic distillate and the oil C from a naphthenic distillate by treating the latter with a solid adsorbent or with concentrated sulfuric acid or oleum and with a solid adsorbent. very Favorable results can also be achieved if the oil A is produced from a naphthenic distillate was and the oil C from a naphthenic distillate by extraction with a opposite the aromatic components of the oil selective solvent and treatment of the aromatic extract with a solid adsorbent.

So if the insulating oils according to the invention contain both an oil A and an oil C and an oil B, very Favorable results can be achieved if the oil A was prepared from a naphthenic distillate which Ol B from a naphthenic distillate by extracting the distillate with an opposite to the aromatic Components of the oil selective solvent and treatment of the raffinate with concentrated sulfuric acid or oleum and was obtained with a solid adsorbent and the oil C from a naphthenic base Distillate by treating the latter with concentrated sulfuric acid or oleum and with a solid adsorbent. Very favorable results can also be achieved if the oil A in such a case from a naphthenic distillate by extraction of this distillate with a solvent selective to the aromatic components of the oil and catalytic hydrogenation of the raffinate was obtained and the oil C from a naphthenic distillate by treating the the latter made with concentrated sulfuric acid or oleum and with a solid adsorbent became.

The insulating oils according to the invention contain, as mentioned, possibly low proportions of oxidation inhibitors, preferably alkylphenols. The proportions of these oxidation inhibitors are z. B. 0.01 to 1 Percentage by weight, based on the insulating oil. A specific example of an oxidation inhibitor according to the invention

A suitable alkylphenol is 2,6-di-tert-butyI-4-methylphenol The example illustrates the invention.

I! c i s ρ i c I

It. seven oils A (oil Ai to A7) are made from two mineral oils (mineral oil 1 ij.id 2) by catalytic hydrogenation, distillation at atmospheric pressure, treatment with 5 percent by weight of concentrated sulfuric acid (except in the case of oil A ₄ , for which 10 percent by weight of concentrated sulfuric acid were used), 5 neutralization with alcoholic sodium hydroxide solution, washing until neutral reaction and treatment with 3 percent by weight of a commercially available bleaching earth (e.g. a bulk density of 400 g / liter). The mineral oils 1 and 2, which were used as starting materials for the catalytic hydrogenation, have the following properties:

10 mineral oil 1:

Neutral, naphthenic distillate with a viscosity (20 ° C) of 18.9 mm ² / s, a sulfur content of 1.6 percent by weight, a 5% boiling point of 290 ° C and a 90% boiling point of 350 ° C;

Mineral oil 2:15

Neutral naphthenbasiches distillate having a viscosity (20 ⁰ C) of 314 MMCs, a sulfur content of 1.9 percent by weight, a 5% boiling point of 295 ° C and a 90% boiling point of 400 ⁰ C.

Table I shows the conditions for the catalytic hydrogenation and the properties of oils A ₁ to A ₇ . For comparison purposes, the properties of an oil A * are also taken into account in Table I 20

The oil A * is an oil produced in the same way as an oil A, but after the atmospheric pressure distillation no treatment with concentrated sulfuric acid or with fuller's earth is carried out.

Table I.

Starting oil oil

Ni-Mo-S / Al ₂ O _{3 catalyst}

oil I oil 1 Λΐ 1 oil 1 oil 2 oil 2

Ni-Mo-S / AljO ₃ Ni-Mo-SMI ₂ O ₃ Ni-Mo-S / Al ₃ O ₃ Co-Mo-S / AbO, Co-Mo-S / Al ₂ Oj Co-Mo-SZAl ₂ O ₃

Conditions for the
catalytic hydrogenation
Pressure, kg / cm ² 100 100 100 50 100 100 10 & (^ speed,
kg / liter · h 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Gas flow rate,
Normal liter / kg 150 150 150 150 150 150 150 Temperature, ⁰ C 325 350 400 375 350 350 400

Product properties

Oil no.

A »A,

A ₃

A ₄

A ₅

A ₇

Aromatic content,
Weight percent 37.5 35.5 25.5 Sulfur content,
Weight percent 0.18 0.12 0.01 Viscosity at 2O ⁰ C, mmVs 17.0 16.8 15.5

29.5

<0.01

11.8

36.0
0.01
16.2

30.0 0.04 17.1

39.5
0.15
36.1

34.5 0.02 26.3

Furthermore, two oils B (oil Bi and oil B ₂ ) and four oils C (oil Ci to oil C ₄ ) are produced as follows:

oil Bi Produced from mineral oil 1 by extraction with SO ₂ , treating the raffinate with 5 percent by weight of oleum, neutralization with alcoholic sodium hydroxide solution, washing until neutral and treating with 1 percent by weight of the 5 bleaching earth used to produce oils Ai to A7;

oil B ₂ produced from the mineral oil 2 by extraction with SO ₂ and catalytic hydrogenation of the
Raffinate;

oil Ci made from a naphthenic base «! Distillate more concentrated by treating with 2 percent by weight Sulfuric acid, neutralization with calcium oxide and treatment with 3 percent by weight 10 the fuller's earth used to produce oils Ai to A7;

oil C ₂ produced like oil Ci, but starting from a lighter naphthenic distillate;

oil C ₃ produced from a naphthenic distillate by treating with 10 percent by weight of a
commercially available fuller's earth (e.g., a bulk density of 530 to 750 g / liter);

Oil C ₄ produced from a naphthenic distillate by extraction with SO ₂ and treating the extract in four stages with 20 percent by weight of that used to produce oil C3
Fuller's earth, with 5 percent by weight of fuller's earth used in each stage.

The properties of the oils Bi, B ₂ and C ₁ to C ₄ are shown in Table II.

20 Table II

Thirteen insulating oils (insulating oil I to XIII) are now produced by mixing one of the oils A with
one of the oils C and optionally one of the oils B mixed. The mixing ratios and the properties of the insulating oils obtained are shown in Table Hl. For comparison purposes, the corresponding ones are also included
Values for oil I 'are given in table ΩΙ

The Pirelli gas absorption test is carried out using the method described in "The Journal of the Institute olE Petroleum", 35, No. 311,
modified Pirelli device described on see 735-754

Oil no.
B, B ₂ C, C ₂ C ₃ C ₄ Viscosity, mm ² / s 19.5
(20 ° Q 34.5
(20 ° q 116 22nd
(37.8 "Q (20 ⁰ C) 75 Sulfur content,
Weight percent 0.01 <0.01 13th 13th 1.6 33 Aromatic content,
Weight percent 5 5 55 51 44 90

Table HI Product features

Isoieröl-Nr.
1 "I.
Proportions, percent by weight
97.5 A * 97.5 Αι
2JC ₁ 2.5 C, 36.0 II
97.5A ₂
2.5C ₁ HI
97.5A ₅
2.5 C, IV
97.5 A ₄
2.5C ₁ V
97.5 A ₅
2.5Ci VI
97.5 A ₆
2.5 C, K)
Ω 38.0 0.17 26.5 30.0 37.0 31.0 40.0 0.22 17.5 0.05 0.04 0.05 0.10 0.20 17.8 136 16.6 12.5 16.9 17.8 36.2 ο 136 -50 134 136 136 136 154 O -50 0.004 -50 -50 -50 -50 -45 0.005 0.0007 0.002 0.007 0.009 0.002 0.009 0.0027 0.0006 0.0007 0.0008 0.0005 0.0007 0.95
1.00 1.30
1.00 0.05
0.10 0.90
0.95 1.05
0.95 1.05
1., OO 0.90
0.90 1.10
1.05 0.09
0.20 0.20
0.030 0.03
0.10 0.03
0.10 0.03
0.15 0.02
0.10 0.02
0.10 0.40
0.070 0.15
0.017 0.15
0.016 0.17
0.037 0.15
0.015 0.18
0.020

Aromatic content, wt .-% Sulfur content, wt .-% Viscosity at 20 ° Cmm ² / s Flash Point (PMcc) *). "C Pour point, ° C Pirelli gas absorption test at 50 ° C and 10 kV; Gas absorption, ml / min. Dielectric loss factor at 90 ° C, tg δ Dielectric loss factor after four months of storage at 35 ° C, tg δ

BS-148 (1959) Oxidation Test Sludge, wt% Neutralization Number, mg KOH / g

Oxidation test of the IEC publication Sludge, Cw% Neutralization Number, mg KOH / g

VDE 0370/66 Baader test (3 days) saponification number, mg, KOH / g dielectric loss factor at 90 ° C, tg δ

*) Pensky-Martens apparatus (with closed lid)

The values listed in table HI indicate the following:

1) The results of the Pirelli gas absorption test show that all of the listed insulating oils have good gas absorption properties exhibit.

2) From the comparison of the properties of the insulating oil I and the oil Γ it can be seen that the oxidation resistance of the finished insulating oils is improved by the acid treatment of the oils A (es
less sludge and acid formation occurs and the resistance of the dielectric dissipation factor is noticeably improved). A comparison of the properties of the insulating oil I with those of the
Insulating oils XI to XIII shows that the oxidation resistance of the finished insulating oils can be further improved by incorporating an oil B into the mixture. 10

3t) The insulating oils I to XIII according to the invention meet the most diverse international standard requirements.

Il

! Table III continuation insulating oil no. VIII IX 95 Aj 95A ₂ X XI XII XIII requirements Ni Product features VII Proportions, percent by weight 5C ₂ 5C ₃ O 97.5 A ₇ 98.5 A ₂ 77.5 A, 57.5 Ai 57.5Ai to 2.5Ci 27.0 27.0 UC ₄ 20 bi 40 bi 40B ₃ p 0.11 0.10 2.5Ci 2.5 Ci 2.5Ci Oi
O 35.0 15.8 15.6 26.5 29.5 24.0 24.0 0.07 134 135 0.06 0.17 0.13 0.10 ; Aromatic content, wt .-% 26.6 -50 -50 15.8 18.1 18.4 22.5 Sulfur content, wt .-% 150 0.003 0.002 136 138 142 142 Viscosity at 20 ° C mm ² / s -45 0.0005 0.0010 -50 -50 -50 -50 Flash Point (PMcc) ^# ), ° C 0.006 0.003 0.002 0.001 0.001 Pour point, ° C 0.0005 0.0010 0.0005 0.0005 0.0005 max. 0.004 (VDE) ^ 3 Pirelli gas absorption test at 50 ° C and 10 kV; Gas absorption, ml / min. Dielectric loss factor at 90 ° C, tg δ 1.00 0.95 Dielectric loss factor after four months of storage at tg δ 0.90 0.90 Dielectric loss factor after four months of storage at 35 ° C, tg δ 1.05 0.85 0.85 0.70 0.85 max, 1.20 BS -148 (1959) Oxidation Test 0.90 0.03 0.02 0.90 0.95 0.80 0.80 max. 2.5 Sludge, wt% 0.15 0.10 Neutralization number, mg KOH / g 0.02 0.03 0.03 0.02 0.03 max.0.10 Oxidation test of the IEC publication 0.10 0.18 0.16 0.15 0.10 0.10 0.15 max. 0.40 Sludge, wt% 0.020 0.022 Neutralization number, mg KOH / g 0.10 0.18 0.15 0.10 0.15 max. 0.20 VDE 0370/66 Baader test (3 days) 0.010 0.030 0.016 0.008 0.010 max. 0.05 Saponification number, mg, KOH / g Dielectric loss factor at 90 ° C, tg δ *) Pensky-Martens apparatus (with closed lid)

Claims (18)

Patent claims: 1. insulating oils, which are made from mineral oils by catalytic hydrogenation and treatment with a solid Adsorbent containing oils and optionally oil components with a lower aromatic content than containing the hydrotreated oils, characterized in that the insulating oils from a) 40 to 99.5 percent by weight of a naphthenic or paraffinic mineral oil by catalytic Hydrogenation and treatment with concentrated sulfuric acid or oleum, as well as with a solid one Adsorbent obtained oil (oil A), ίο b) 0 to 40 percent by weight of a naphthenic or paraffin-based mineral oil, which has an aromatic content below 20 percent by weight, which is also lower than in oil A (oil B),
c) 0.5 to 20 percent by weight of a mineral oil which has an aromatic content above 40 percent by weight, which is also higher than with oil A and / or the mixture of oil A and oil B (oil C), as well as optionally
d) low levels of an oxidation inhibitor exist. 2. Insulating oils according to claim 1, characterized in that they contain an oil A which has been produced at 20 "C ^{from a mineral oil with a viscosity of 10 to 100 mm 2} / s, preferably 15 to 50 mm ^{2 / s.} 3. insulating oils according to claim 1 or 2, characterized in that they contain an oil A, which by catalytic hydrogenation at temperatures of 250 to 425 ° C, preferably 300 to 400 ⁵ C, pressures of 10 to 200 kg / cm ² , preferably 25 up to 150 kg / cm ² , a gas flow rate of 50 to 5000 liters / kg of oil, preferably 100 to 500 liters / kg of oil, and with an oil flow rate of 03 to 3 kg / liter of catalyst - h, preferably 0.5 to 2 kg / Liters of catalyst · h, and subsequent treatment with concentrated sulfuric acid or oleum and with a solid absorbent. 4. insulating oils according to claims 1 to 3, characterized in that they contain an oil A, which by catalytic hydrogenation in the presence of one of nickel or cobalt sulfide and molybdenum sulfide on one Alumina support existing catalyst and subsequent treatment with concentrated sulfur 30 acid or oleum as well as with a solid adsorbent has been produced 5. insulating oils according to claims 1 to 4, characterized in that they contain an oil A, which by catalytic hydrogenation and subsequent treatment with concentrated sulfuric acid or oleum as well with a solid adsorbent during the catalytic hydrogenation more than 50 percent by weight, preferably more than 85 percent by weight, of the sulfur contained in the oil 35 were separated. 6. insulating oils according to claims 1 to 5, characterized in that they contain an oil A from a mineral oil by catalytic hydrogenation followed by 5 seconds to 1 hour Treatment at temperatures from 0 to 75 ° C with 0.5 to 30 percent by weight based on the treated oil, 80 to 100 percent concentrated sulfuric acid or with oleum that is up to 30 percent dissolved 40 contains sulfur trioxide 7. insulating oils according to claims 1 to 6, characterized in that they contain an oil A, which at its production with 03 to 30 percent by weight, preferably 1 to 5 percent by weight based on the treated oil, solid adsorbent has been treated 8. insulating oils according to claims 1 to 7, characterized in that they are an oil B with an aromatic content contain below 10 percent by weight. 9. insulating oils according to claims 1 to 8, characterized in that they are an oil B with a sulfur content below 1 percent by weight, preferably below 03 percent by weight. 10. Insulating oils according to claims 1 to 9, characterized in that they contain ^{an oil B with a viscosity of 10 to 40 mm 2} / s at 20 ^{° C.} 11. insulating oils according to claims 1 to 10, characterized in that they desolder an oil B from a naphthenic distillate has been produced by a refining process in which a catalytic hydrogenation and / or extraction with one opposite the aromatic components of the oil selective solvents, optionally in combination with other refining processes, preferably treatment with a solid adsorbent or treatment with concentrated sulfur 55 acid or oleum and with a solid adsorbent. 12. insulating oils according to claims 1 to 11, characterized in that they are an oil C with a sulfur content contained above 03 percent by weight. 13. Insulating oils according to claims 1 to 12, characterized in that they are 90 to 993 percent by weight from an oil A and from 03 to 10 percent by weight from an oil C, preferably from 95 to 983 60 percent by weight of an oil A and 13 to 5 percent by weight of an oil C consist. 14. insulating oils according to claim 13, characterized in that they consist of a naphthenic base Distillate produced oil A and an oil C, which is either from a naphthenic distillate a) by treatment with a solid adsorbent or with concentrated sulfuric acid or Oleum and with a solid adsorbent or b) by extraction with a solvent which is selective with respect to the aromatic components of the oil and treating the aromatic extract with a solid adsorbent has been made exist. 15. insulating oils according to claims 1 to 12, characterized in that they are 50 to 89.5 percent by weight from an oil A, from 10 to 40 percent by weight from an oil B and from 0.5 to 10 percent by weight an oil C, preferably 55 to 83.5 percent by weight, an oil A, 15 to 40 percent by weight an oil B and 1.5 to 5 percent by weight of an oil C. 16. Insulating oils according to claim 15, characterized in that they are an oil A, which is based on a naphthen Distillate by extraction with a selective towards the aromatic components of the oil Solvent and treat the oil with concentrated sulfuric acid or oleum and with a solid one Adsorbent has been produced, and an oil C which is made from a naphthenic distillate Made by hand with concentrated sulfuric acid or oleum and with an adsorbent has been included. 17. insulating oils according to claim 15, characterized in that they are one of a naphthenic distillate produced oil A, an oil B, which is obtained from a naphthenic distillate by extraction with a Solvent selective to the aromatic components of the oil and catalytic hydrogenation of the raffinate has been produced, and an oil C, which is obtained from a naphthenic distillate by hand made with concentrated sulfuric acid or oleum and with a solid adsorbent has been included. 18. insulating oils according to claims 1 to 17, characterized in that they are 0.01 to 1 percent by weight an oxidation inhibitor (d), preferably an alkylphenol and in particular 2,6-di-tert-butyl-4-methylphenol, contain.