DE2003533A1 - Process for the production of stable insulating oils with a low pour point - Google Patents

Description

Eeso Research and Engineering (US 79 * 688 - prio 28.1.1969 Coepany 67-6 ₎ .

Undo η. NJ / V.St.Ao ^

Hamburg, January 26th, 1997

Process for the production of stable insulating oils with low

Pour point

The present invention relates to a process for the production of extremely stable insulating oils, in particular those oils which have a high flash point and a low pour point and are obtained from paraffinic distillates.

Insulating oils are used in transformers and electrical Equipment such as circuit breakers are used and have a relatively low viscosity, high dielectric strength, a relatively high flash point and a low pour point. In addition, it is required; that these oils are non-corrosive, have no acid, alkali or sulfur content and are also resistant to oxidation and do not form sludge.

For the production of insulating oils is generally used by paraffin-free naphthenic crude oils assumed, which are however not available everywhere and consequently and also extremely expensive because of the high transport costs

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βInd. Although you can get from these crude oils Insulating with äußeret low pour point without dewaxing or careful monitoring of Ausraasses fractionation or the cutting width in the distillation "contain these oils, a large proportion of sulfur and nitrogen that high because of the stability requirements that are placed on insulating oils need to be removed.

Nan can also completely or extremely stable insulating oils partly from wax-containing crude oils using conventional ^ Establish refining processes when oils are not required due to the moderate climatic conditions, which must have a particularly low pour point or cloud point. However, if extremely low pour points are required, the dewaxing procedure becomes of paraffinic distillates at temperatures below -40 ° uneconomical compared to the production of insulating oils from naphthenic crude oils.

A process is known in which the deep paraffinity » avoided and relatively inexpensive, low « viscous oils with an exceptionally low touch point paraffinic distillates are obtained »With this process, a wide poraffin-containing fraction is obtained

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soharf fractionated to obtain a narrow Mittelsohnitt of suitable viscosity, which is then entparafflnlert at about -17 # 8 ° C, to obtain an oil with a entparaffinlertes Stookpunkt of -45.6 ⁰ C or lower. This narrow cut can also be subjected to a solvent extraction before dewaxing, without the sticking point of the product being significantly affected. The difficulties encountered in this process are related to the nature of the low stick point oil obtained. Although these oils have low pour points, their cloud points, which indicate the onset of paraffin precipitation, are relatively high and are close to the paraffinization temperature that was maintained in the manufacture of the oils. This in turn makes the product's stick point extremely sensitive to paraffinic impurities, such as paraffin wax, especially since such impurities always occur in the processing lines during the phenol treatment, in the hydrofinishing and in the dewaxing plants, which are normally operated with paraffin-containing waste streams with a high stick point. Rs was found that a Paraffinwechsee is raised to a product obtained by the above method ervahnten insulating oil having a cloud point of -24, ⁰ ^ C Stockpunlct of from -45.6 ° to -20.6 ° already by adding 0.5 $ while adding the same

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Amount of paraffin wax to a waoha-free naphtheniaehen Ol 4er glelohen Viekoaität and with the same stook point dleaen stook point not affected at all.

The present invention has also set the task fix these disadvantages xu and a verbeaaertea procedure xur production of high-quality insulating oils old a lesser one Sapfindl reacts to impurities in the form of paraffin to propose

To solve this problem, the procedure is that one separates the insulating oil fraction from a previously dewaxed oil fraction; the previously dewaxed fraction, which contains the desired insulating oil as the middle cut, is treated in such a way that aromatic and polar constituents are removed before dewaxing. The entparafflnierte fraction is then hydrofined prior to fractionation to improve the color and oxidation resistance "

Ia following the invention with reference to drawings and Examples are explained in more detail; show it:

Flg. 1 shows a flow diagram of the process according to the invention for the production of insulating oil;

2 shows a similar part of the model to be fractionated Distillation column used, with which the isolating fraction and a light lubricating oil with low

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The pour point is separated from the dewaxed hydrocarbon oil containing the fraction will. -

With the plant according to PIg * 1. a paraffin-containing crude oil Passed via line 1 into a crude oil distillation plant 11, where the crude oil is fractionated into several fractions will. The crude oil, which contains the olive oil fraction, is withdrawn from the vacuum part of the crude oil distillation system via line 2 and into an extraction system 12 where the aromatic and polar components in the vacuum oil fraction are reduced by selective extraction. The solvent used in the extraction is introduced into the system 12 via line 3 and via the Line 4 withdrawn. The raffinate is drawn off overhead from line 5 and into the dewaxing plant 15 promoted. Here is the paraffin content of the vacuum oil fraction to the desired value by cooling to a certain Temperature decreased. This cooling causes the paraffin to precipitate, which is then filtered through Will get removed. Usually the paraffinic oil is diluted with a suitable solvent before dewaxing; in this case the dewaxing solvent is introduced into the dewaxing system 15 via line 6. The diluted oil that precipitated the

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Contains paraffin, is withdrawn from conduit 7, wherein the paraffin is then separated in conventional manner, for example through a filter 14 and the diluent is evaporated with a suitable device 15 »This corresponds · parafflnierte oil is then subjected to Hydrofinieranlöge via line 8 16, the hydrofined ölrakticxi is then via line 9 to a fractionating one

κ directed distillation column 17, where the isoller oil fraction is separated off as a middle cut and leaves the distillation column via line 10b. The lighter components which are unsuitable as insulating oil * y / earth are drawn off overhead through line 10a. The heavier fractions, which can be used as lubricating oil, contain the high-boiling paraffin impurities and are withdrawn as bottom products via line 10c = As FIG -

■ impurities as soil products via the line 1Od subtracted from. The remainder belonged to the older parliamentary group is withdrawn via line 10e and can be used as a lubricating oil can be used with a low pour point *

With the process according to the invention, an extremely stable insulating oil is obtained from any paraffinic crude oil, the crude oils from Western Canada, Saudi Arabia, Kuwait,

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. · ■.; -. - 7 * ■
Panhandle, North-Louisiana and Tia jiaana "

PIe Vakuümgasölfraktion which is withdrawn from the Rohdestillatiansaudage generally has a 5 to 95 ~ J6 boiling "range 288-400 ° C. The pour point of this fraction is generally between 1.6 to 21.1 ⁰ C. This fraction apparently contains the Isolierölfraktion which according to the invention to be isolated, "It is essential, however, that this fraction contains the Isolierölschnitt as a center section, the heifit that the vacuum gas oil fraction contains both lower boiling and higher boiling fractions.

The aromatic and polar components are removed from the vacuum gas oil fraction by bringing it into contact with a solvent which has a preferred selectivity for the components concerned. Such selective extraction methods are well known; The solvents used include phenol, furfural and the likec In general, about 0.5 to 4 parts by volume of solvent are used per part by volume of oil; Temperatures in the range from 48 to 121 C and pressures from 0 to 17 »6 kg / cm are used.“ In general, the direction of flow of the solvent is downwards and the exchange takes place in countercurrent to the upwards

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flowing oil takes place under such conditions that the more aromatic and polar components in the solvent to be resolved. The extracted phase is withdrawn from the extraction zone and processed further in such a way that the solvent is separated from the aromatic and polar compounds will. The solvent can then be returned to the treatment zone. In addition, roughly in that Separated raffinate entrained solvent prior to dewaxing.

Dewaxing is in a known manner performed "For example, nan, the gas oil fraction with one or more suitable Bntparafflnierungsmltteln such as liquid propane, methyl ethyl ketone, methyl isobutyl ketone or mixtures of these brought into contact _o In general, the mixture of oil and solvent to temperatures between -6.6 is and -ko C cooled. The pour point of the final insulating depends t, oth of dewaxing "temperamental door as also on the corresponding solvents used.

. Hydrofining occurs through contact between the dewaxing oil with a suitable hydrofining catalyst «which contains sulfides or oxides of metal combinations,

.-jy; ·; ■ 8ü9iff7172p originally inspected

such as cobalt and molybdenum, nickel and molybdenum, nickel and tungsten, and the like. Generally, the Irn Hydrof occurs! Kidney characterized in that the dewaxed oil over a fixed bed with a Durchsatzgesehwindigkeit of 0.5 to 3.0 V / V / h at temperatures between 177 and 543 ⁰ C and under a hydrogen pressure of 21, 1 to 63 # 3

p -

kg / cm conducts. This procedural step is carried out about the coloration, the stability to oxidation and the sulfur!

to improve the content of vacuum gas; this procedure « step can also be left out «. Fractionation the dewaxed vacuum gas oil fraction becomes special advantageously brought about by a fractional distillation, which is directed in such a way that one is a proportionately sharp separation, sswischenden individual fractions achieved "' In general, the insulating oil fraction should be cut in this way that the $ 5 to $ 95 boiling range between $ 316 and 371 ° G of course, the exact boiling range depends this group depends on the requirements to be met.

Oils hShersiedende fraction generally has einen5 to 9556 ~ boiling range between 410 and 36O ⁰ C. This fraction contains the high boiling impurities * the one extending in the i / orherigen ¥ @ rarbeitvingsetia

however, it can be used directly as a lightweight®

In general, d & p ^ StoekpunM 4ia @ es Froöti ^ 'as-i »a

Bereloh awlβοhen «17 * 8 and -28.9 ° ^c « Q If necessary, the stook point of this product can be improved by further fractionation »Removes a large amount of bypass product from the column and removes the high-boiling impurities as bottom product. Here, the amount of bottom product is approximately} to 20% of the total vacuum gas oil fraction and has a boiling range swiaohen 371 and 5? 8 ^O C, the upper limit on the type and quantity of impurities present depends.

example 1

Ka a paraffin-containing West Canada crude oil (P ^ tatoina) was introduced via line 1 into a conventional crude oil distillation plant 11. An oas oil fraction, which made up 2.67 % of the crude oil used, was drawn off via line 2. and a 5-9556 - boiling range between 304 ° C and 58o C ⁰

would have. The boiling range of this fraction was determined on a distillation column with 15 trays, which was operated with a reflux ratio of 5: 1 . The Stookpunkt the vacuum gas oil fraction was 10.0 ⁰ C. Subsequently, the vacuum gas oil fraction into a Bbctraktioneanlage M was passed 12 where the excess aromatic and ! polar components have been removed by phenol extraction

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- π

The volume ratio of the phenol passed through line 3 and the vacuum gas oil fraction introduced via line 2 was 1.2: 1. 27 # of the vacuum gas oil fraction was removed in the extraction phase via line 4 Raffinate phase isolated and the Ent paraff inierusigsanlage 13 passed through line 5. The raffinate was ketone with a mixture of 50 parts of methyl ethyl ketone and 50 parts Methylisobuty! Dilute the ratio of solvent to oil was X 5 to X ₀ The Nisohung of oil and solvent was cooled to ⁰ C 23.3. The precipitated paraffin was filtered and the ketone solvent was removed by distillation. The yield of entperaffiniertem oil was, based on the pare the Ent ffinierungs plant trains recycle material te / 72 jsy The pour point of the oil was -26, I ⁰ C, the cloud point at -24.4 ° Cj density was 34.0 API, the viscosity d · «oi * was 55, * SÜ3 at 37.8 ° C, the oil contained about 14 parts aromatic components and 0.07 # sulfur. The oil was then waxed with a typical cobalt / molybdate sulfide -Katalyaotor to improve the color and oxidation stability and to reduce the sulfur content a hydrofihted. The dewaxed oil was via line 8 into the hydrofining system 16 with a bucket

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aatzgesohwlndigkelt of 1.0 V / V / h at 2J52 ° C and one Hydrogen pressure of 28.1 kg / cm. That from the Product withdrawn on line 9 had a sulfur content of £ 0.025. The hydrated product was then on the Line 9 passed into the distillation column 17. These Fractionation column is designed in such a way that the separation corresponds to a column with 15 trays, the batchwise with | a RUokflussratnie of 2: 1 is operated. at the preferred way of working 4 fractions were withdrawn, well

a) a fraction boiling below? 27 ° C (29.6 LV £),

b) a fraction boiling between 327 and 563 ⁰ C (49.8 LV #), 0) a ^{fraction boiling between 262 and 288 0} C (15.0 LV $),

d) a residue fraction (5.6 LV *).

These fractions had the following 5 to 95 % - Siedeberelohe, which were attached to a Deetlllationskolonne with 15 floors! and a RUokfluSverhKltnls of 5: 1 were determined ι

a) 890 to 325 ⁰ C ä fe) 284 to 263 ° C \ 0) 257 to 288 ° C ^! β) 200 to 416 ° C.

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The Stookpunkte and viscosities at 37.8 ⁰ C were as follows: a) -20.6 ⁰ C, 44.6 SUS
bK-34.4 ⁰ C, 56V8 SUS
c) -37 ⁰ C. 78.5 SUS
SUSo

If one of the fraction b) 0.06 .Jf dines 2,6-di = tert _o - S ^J utyl ". paraaresol as an oxidation inhibitor and "07 % of a paraffin-activated naphthalene added as a pour point depressant" which was obtained in a yield of 0.7 % based on the crude oil, all requirements according to the Canadian Standards Association specifications (050-1965) for transformer oils are met. The individual values are given in Table 1 below.

Tabel I. Result CSAoSpecificatlon
CJ50-1965 Characteristics ASTM 179 290 mino Flash point (more open
Crucible) in ⁰ C, D 92 -57 Focus (more open ■ 320 min » Crucible) in ⁰ G D 92 -57 Viscosity at ".. 56 * 7 62.0 max « 37.8% SUS δ 88 - ■ 56 Viscosity at . 170 ■ 240 max. 4.4 ° c, extrapolated,
in SUS ~ 4>

- 14 -

Table I continued

Characteristics

ASTM

Pour point in C ASTM paint

Durohsohlagsfastlglceit in kv

Interfacial tension in dyn / om Specific density at 15.6 ° C Neutrality number in MgKOH / g more corrosive Soh sulfur content

Stability, visible sludge / Orenzf 1 surface tension / Ifeutrelisation number

D 97 -D 1500 -

D 877 -D 971 - Ό 1298-55

O 974 -ί) 1275 -

J) 1314 ■ » (24 hours)

Result of CSA-SpeoifioaUon C5O - I965

-45.6

-50 max. 1 max.

26 min «

40.8 0.852

<O, O1

0.906 max.

0.05 max.

non-corrosive corrosive

none / 40.7 / none /> - 20 / 0.01 <-0.05

Fraction 0) meets all the requirements for a light lubricating oil with a low insertion point _{or the like}

Example 2

The procedure was analogous to Example .1, but only three fractions were obtained in the last distillation. The Siedeberelohe of the fractions, the values for the 5 to 95% -Siedebereiche old a 15/5-Destlllation that Stookpunkte and the viscosities at 57.8 ⁰ C are listed in the following table. The values show that fraction b) are identical

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Sigenso adhesives such as the isoller oil fraction according to Example I hat «BIe fraction c) has a slightly higher pour point and a slightly higher viscosity, but was also obtained in higher yield and still meets the requirements for a light lubricating oil ·

Tabel

Boiling range 29.6
20.6 5-95 £ area h pour point viscosity
in SUS below 527 ⁰ C
im - 565 ° C
above 565 ⁰ C 879
524
559 - 535
- 563
- 598 -20.6 ⁰ C
-28.9 ⁰ C .44.6
.56.8
85 * 9. Example 5

Again, Example 1 was never used, but the finishing step was omitted. Here, an isoiler oil fraction b) was obtained with a boiling range between 521 and 56I ⁰ C in a yield of 49.9 LV #. This fraction had a viscosity of 5T # ° ^SUS at 57.8 ⁰ C and a Stgokpunkt of -48.8 ⁰ C without pour point depressants. The oxidation stability, however, was lower than that of an oil hydrofined prior to distillation.,

Oils obtained by the process according to the invention can be used directly as insulating oil or light lubricating oil

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will. In general, even better oils are obtained, if you have an oxidation inhibitor and additionally adding a pour point depressant »For this purpose, known additives can be used, such as, for example butylated hydroxytoluenes as oxidation inhibitors und.Polyacrylate or paraffin-alkylated naphthalenes and the like as pour point depressants.

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Claims (1)

Claims ^/ iC | Process for the production of insulating oils with high stability and low stook point from crude oils containing paraffin, characterized in that a wide vacuum gas oil fraction is dewaxed and the dewaxed vacuum gas oil fraction is divided into at least three fractions, whereupon the insulating oil is isolated from the middle section. ο The method according to claim 1, characterized in that the aromatic and polar components from the Vacuum gas oil fraction removed before dewaxing to improve stability. 3 · Method according to claim 1 and 2, characterized in that that the dewaxed fraction before separation is hydrofined * 4. The method according to claim 1, characterized in that a vacuum gas oil fraction with a 5 to 95% - Sietiebereloh between 288 and 399 ° C to a pour point in a range between <-β * β and -51 »7 ⁰ C deparaffihlert UtM oils dewaxed fraction in at least three sharply separated I ^ raktiorseki ßuftrerint, so that mn as a middle section iiiliififli an insulating oil fraction with a 5 to 95 % boiling range between} 04 and 282 ° C is obtained. 5. The method according to claim 4, characterized in that 'the vacuum gas oil fraction having a 5 to 95% - boiling range between J04 and 379 ° C, and in that the insulating oil is obtained in a boiling range of 324-563 ⁰ C. 6. The method according to claim 4 to 5, characterized in that the aromatic and polar components from the vacuum gas oil vo? removed after the dewaxing and that the dewaxed oil is hydrofined before the separation. ue: sch. 009835/1712