CS257845B1 - A method for producing an electroinsulating cable oil - Google Patents

Abstract

Cable oil produced by dewaxing, acid refining and adsorption refining of the extract of deasphalted residual oil and/or extract of heavy oil distillate of sulfur-paraffinic crude oil or mixed crude oil, wherein at least one of the starting oils is deeply hydrogenated before extraction. During hydrogenation, part of the most polar components of the oil, for example resins, polyaromatics and heterocompounds, is converted into less polar cyclic compounds, thereby reducing the need for refining the oil with sulfuric acid in the production of cable oil without adversely affecting its quality. Cable oil produced by the proposed process is a suitable raw material for the preparation of cable impregnation material with good electrical insulating properties, oxidation stability and strength against gas release.

Description

257845

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the production of electroinsulating cable ducts from extracts of deasphalted residual oil and heavy oil distillate of sulfur-paraffinic oil or petroleum mixed mixed. The cable oils used to prepare the impregnating material for impregnating the paper insulation of high-voltage cables are produced from pseudorafinates formed during the extraction refining of sulfur-paraffinic oils by the process of U.S. Pat. AO 191 478 or pseudorafinates of deasphalted residual oils according to MSA. AO 220 988. The processes include dewaxing of pseudorafinates, hydrogenation or refining with sulfuric acid and finalization with a solid adsorbent. According to the procedure of PV 4328-80, the production of cable oil and second stage pseudorafinate is proposed by dewaxing and refining with sulfuric acid or hydrogenation. Traditional processes for the production of cable oil oils from non-paraffinic oil extracts are due to the lack of such ropes in decline.

Patents pLr No. 120 331, 120 334, 120 341 and 120 342 disclose processes for producing cable impregnating masses and various blends comprising sulfur-paraffin-asphaltic oil oils, for example deasphalted residual oil, raffinates and distillate extracts, deasphalt extract, acid raffinates extracts and others. In general, cable oils with very good insulating properties and gas release strengths are produced by processes whose essential node is the refining of sulfuric acid aromatic substances needed to remove most of the high-polarity oil oil components, such as bitumen, bituminous aromatics, and heterosubstitutes. The disadvantage of refining is the excessive formation of environmentally harmful and workable acid resins and multiple neutralization solutions.

The essence of the invention is that the cable oil is produced from extracts resulting from the liquid extraction refining of deasphalted residual oil and heavy oil-distillate oil or mixed oil so as to hydrogenate at least one of the starting oils prior to the extraction refining and to remove the low molecular weight high molecular weight fission fraction by distillation . The extracts are dewaxed, refined with a small amount of concentrated sulfuric acid, neutralized with a hydroxide solution, and purified by contact with a solid adsorbent.

The extracts are a mixture of predominantly low viscosity index aromatics, which pass the extraction from petroleum oils into an extractant, such as furfural, and are freed from the extracts by distillation after phase separation.

The term "mixed oil" refers to a type of oil with a low content of heterocompounds and high-melting paraffinic hydrocarbons.

The hydrogenation refining is carried out in conventional medium pressure hydrogenation conditions in the presence of catalysts which contain actively the metals Co, Ni, Mo, w, metals of the Pt group and rare earth elements separately or in combination of at least two elements, deposited with alumina, amorphous or crystalline aluminosilicate , or on a mixture of at least two of said carriers. By the hydrogenation effect, the conversion of a portion of the most polar compounds, for example, resins, heterocompounds and multicore aromatics, into less polar cyclic compounds is achieved: The desired viscosity and flash point of the oil are obtained by distilling off the light-weight hydrogenation products.

The dewaxing is carried out at a temperature of -10 to -20 ° C with a solvent mixture, for example methyl ethyl ketone + toluene (weight ratio 1: 1), used in an amount of 200 to 500% by weight per oil.

Contacting the oil with an adsorbent, for example, bleaching earth, bauxite, alumina, silica gel, aluminosilicate and others, is used to remove further portions of the polar resins and dry the oil as it is finalized. 3 257845

If, despite the hydrogenation of the feedstocks, the oil has a high polar content and poor electroinsulating properties, it is diluted with a light hydrocarbon fraction, for example gas oil, to a viscosity of 40 to 85 mm 2 s -1 at 50 ° C prior to contacting the adsorbent with 0.1 to 5% by weight. concentrated sulfuric acid at 30 to 65 ° C, the acid raffinate is separated from the smil, neutralized at 50 to 85 ° C with 3 to 10% NaOH in water + ethanol (1: 1 to 3: 1 by weight) ), washed with water and freed from diluent and moisture. The advantage of using the process of the invention as compared to processes for producing cable oil extracts of non-hydrogenated oils is that in the hydrogenation, some polar substances such as resins, hetero compounds and polyaromatics are removed and have a beneficial effect on improving the insulating properties of the oils. At the same time, an improvement in the electrical insulating properties of the oils is achieved. At the same time, the need for refining sulfuric acid oil is reduced, reducing the consumption of chemicals, generating environmentally harmful waste, waste disposal costs and increasing the yield of cable oil. Compared with the cable oil that would be prepared under the same conditions by the opposite of the operations, ie extraction refining, hydration of the extract, the cable oil according to the invention has a higher viscosity and a lower viscosity index, which is suitable for the solubility of the aromatic bituminous additives in oil. cable impregnating material and paper impregnation conditions for cables when low viscosity of the material is desired at an impregnation temperature of at most 100 ° C.

According to the invention, the process for producing a cable oil provides the desired properties of the oil, for example a low viscosity index, a high viscosity at 50 ° C, an oxidation stability, an isolation property of miscibility with additives to increase the viscosity of the impregnating material and to improve its gas release stability.

By way of illustration, examples of cable oil production are given, but these do not limit the invention. Example 1

The deasphalted residual oil extract is mixed in a weight ratio of 1: 4 with the extract oil distillate which has been hydrogenated at 380 ° C, a hydrogen pressure of 4.0 MPa, a catalyst loading of 0.6 h in the presence of a hydrogenation catalyst containing Ni and Mo metals deposited in a 1: 4 ratio. on alumine in an amount of 3.0 to 15% by weight, calculated on their oxide form. The hydrogenate yield is 93% by weight. The properties of distillate, hydrogenate with distillation at 400 ° C and extracts are shown in the table.

Table 1

Indicator Distillate Hydrogenate Hydrogenate Extract Deas-Faltizate Extract Extract Mixture Viscosity Index 33 60 1 -3 -1 Flash Point ° C 250 252 254 271 255 Resin Content,% w / w 3.62 1.18 2.41 2.82 2.49 Sulfur content,% wt. 2.29 0.21 0.38 2.83 0.87 Nitrogen content,% wt. 0.2444 0.1290 0.2161 0.309 0.2347

The mixture of extracts is dewaxed with cold and a solvent mixture of methyl ethyl ketone + toluene (weight ratio 1: 1), used in an amount of 300% by weight calculated on oil, solidification of the mixture -12 ° C.

Deparafinate, obtained in 86% yield calculated on the extract mixture, is diluted with 257845 with gas oil to a viscosity of 80 mm 2 at 50 ° C, mixed with 3% by weight of concentrated SO 2 and refined at 50 ° C. . The acid raffinate, after separation of the mixture, is neutralized at 70 DEG C. with 48% NaOH in water + ethanol (3: 2 by weight), washed with water and freed from diluent and moisture. The raffinate obtained in a yield of 89% by weight is contacted in three steps with 5 + 5 + 2% by weight of bleaching clay at 132 ° C and 30 minutes. the yield of the contacted oil is 87% by weight calculated on the raffinate and 66.6% by weight calculated on the raffinate and 66.6% by weight on the mixture of extracts and the density is given in Table 3. Example 2

The deasphalted residual oil extract used in Example 1 is mixed in a 2: 3 weight ratio with an oil distillate extract which has been hydrogenated at 345 ° F (4.1 MPa), 0.6 h by volume, in the presence of a hydrogenation catalyst containing Co and Mo deposited on alumine at 3.1 and 11.5% by weight, calculated on our oxide form. The hydrogenate yield is 98% by weight. The properties of the distillate, hydrogenate, are shown in Table 2.

Table 2

Indicator Distillate Hydrogenate Hydrogenate Extract Extract Mixture Viscosity Index 36 58 -11 -8 Flash point, ° C 250 252 254 257 Resin content,% wt. 3.86 1.46 2.96 2.90 Sulfur content,% wt. 2.24 1.06 1.57 1.99 Nitrogen content, 8 wt. 0.2508 0.168 0.305 0.307 The mixture of extracts is evaporated in the presence of a mixture of solvents methyl ethyl ketone + toluene (1: 1 by weight), used in an amount of 400% by weight calculated on oil, to -14 ° C. Deparafinate in 84% by weight, calculated on a mixture of extracts, is diluted with gas oil to a viscosity of 60 mm 2 at 50 ° C, mixed with 28% concentrated H 2 SO 4 and refined at 45 ° C. The acid raffinate, after separation, is neutralized at 70 ° C with 4 N NaOH in water-ethanol (3: 2), washed with water and freed from diluent and moisture.

The raffinate obtained in a yield of 89% by weight is contacted with 5 + 5% by weight of a bleaching clay at 123 ° C / 20 minutes. The yield of the contacted oil is 88% by weight based on the raffinate and 65.8% by weight calculated on the extract mixture, the quality of which is given in Table 3.

Table 3

Indicator. Quality Example 1 Example 2 CSN 65 6846 Density 20 ° C, kg.m 972.0 979.6 min. 910.0 Viscosity 50 ° C, mm 2 s 1 327.8 333.2 min. 305 Viscosity 100 ° C, mm ^ .s 24,80 24,84 max 25 Viscosity index 1 -4 inf. max. 22 Freezing temperature, ° C -9 -10 max -8 Flash point, ° C 256 258 min. 220 Acid number, mg KOH / g 0.015 '0.015 max 0.10 Caustic test 0 0 max 2

Claims (3)

257845 Table 3 - continued Quality indicator Example 1 Example 2 ČSN 65 6846 Ash content,% wt. 0.008 0.009 max 0.01 Resin content,% wt. 0.71 0.78 - Insulation Resistance 100 ° C, IO1® Ohmm - Supplied 2.3 2.2 min. 1.0 - after artificial aging 0.50 0.44 min. 0.3 Loss factor 100 ° C, - in delivered condition 0.0088 0.0099 max. 0.02 - after artificial aging 0.0545 0.0559 max., 0.065 OBJECTS A process for the production of electroinsulating cabel oil for the preparation of cable impregnating material from deasphalted residual oil and / or heavy oil distillate of sulfur-paraffinic or mixed oil by extraction refining, solvent dewaxing with an extract with a viscosity index of at most 15, acid refining of deparafinate and contacting with solid adsorbent, characterized in that at least one of the starting oils is hydrogenated at 300 to 400 ° C, preferably 330 to 380 ° C, 2 to 10 MPa, 0.2 to 2 vol. , Preferably 0.4 to 0.8 h by volume of gaseous and liquid phases of 50: 1 to 500: 1 in the presence of hydrogen or hydrogen-containing gas and a hydrogenation catalyst comprising a combination of metal oxides or sulfides. and VIII. the alumina or aluminosilicate and periodically prepared hydrogenate groups of the periodic system are freed from distillation by boiling up to 380 ° C at 0.1 MPa. 2. The process according to claim 1, characterized in that the acid refining is carried out by contacting with 0.1 to 5% by weight, preferably 2 to 3% by weight, of sulfuric acid calculated with oil and 96% of acid and neutralizing the oil raffinate phase alkaline hydroxide solution. 3. A method according to claim 1, wherein contacting the oil with a solid adsorbent-type alumina, aluminosilicate or silica gel in an amount of up to 15% by weight of the adsorbent calculated on the oil is carried out in one or more stages at a temperature of 100-180 ° C, preferably 110-140 ° C. The temperature of one contact is at most 60 minutes, preferably 20 to 30 minutes.