JPH0438084B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing electrical insulating oil, which comprises treating a pyrolysis oil fraction from a pyrolysis process using petroleum heavy residual oil as a raw material. In recent years, due to the depletion of petroleum resources, heavier crude oil has been used, and as a result, the amount of by-product heavy residual oil such as distillation residue oil has also tended to increase.
However, this heavy residual oil has low industrial utility value due to its high viscosity and high sulfur and metal content. On the other hand, the only form of utilization of such heavy residual oil is as a raw material for thermal decomposition processes such as coking. The coking process of this heavy residual oil yields liquid material, ie, pyrolysis oil, along with coke and gas, but the yield of pyrolysis oil in coking is usually quite high, and a large amount of pyrolysis oil fraction can be obtained. It turns out. However, conventional methods for utilizing the pyrolysis oil produced in large quantities have been to perform further processing such as fluidized catalytic cracking, since this oil is relatively rich in aliphatic hydrocarbons and may not have a sufficient octane number. Unless otherwise available, it could not be used as gasoline for automobiles, and could only be used as simple fuel for boilers. Therefore, the utilization of this large amount of pyrolysis oil is becoming a major industrial problem. In view of the above-mentioned circumstances, it is an object of the present invention to produce an excellent electrical insulating oil by treating a large amount of pyrolysis oil fraction obtained as a by-product, which has no utility value other than boiler fuel, in the coking process, for example. It's about getting. By doing so, effective utilization of the pyrolysis oil fraction can be achieved. That is, according to the present invention, heavy petroleum residual oil can be
Electrical insulating oil with low viscosity and low pour point can be obtained by acid-catalyzed treatment of the thermally cracked oil fraction obtained by thermal decomposition at temperatures above 400°C but not exceeding 700°C in the liquid phase. Next, the present invention will be further explained. The petroleum-based heavy residual oil of the present invention refers to atmospheric distillation residue oil, vacuum distillation residue oil, thermal cracking or catalytic cracking residue oil, and various petroleum refining residues such as furfural in the usual sense of the petroleum refining industry. , residual oil extracted with propane, pentane, etc., reformer residual oil, etc., and mixtures thereof. It is necessary that the decomposition temperature of the thermal decomposition process of the present invention is 400°C or higher and does not exceed 600°C.
No thermal decomposition occurs at decomposition temperatures lower than 400℃;
In addition, when the temperature exceeds 600℃, aromatic hydrocarbons, which are themselves highly reactive, become excessive in the resulting pyrolyzed oil regardless of the decomposition time, and high polymers such as resins are removed by acid catalyst treatment. It is not preferable because it is easy to form and the amount of aliphatic olefin having a boiling point in the range of 120 to 290°C is too small. The decomposition temperature is preferably 400-550°C. The decomposition time can be changed as appropriate depending on the main purpose of the thermal decomposition process, such as coke production, viscosity reduction of raw material heavy oil, etc., and can be adopted in the range of 10 seconds to 50 hours, for example. Water vapor or other non-reactive gaseous media can also be present during the decomposition. The decomposition pressure is usually relatively low, at reduced pressure or 50Kg/cm ²
That's about it. Typical thermal cracking processes for heavy residual oil include Hydrocarbon Processing,
As described in Vol. 61, No. 9, September 1982, pp. 160-163, there are the visbreaking method and the coking method. That is, the visbreaking method is a process in which the raw material is thermally decomposed under relatively mild conditions while suppressing the generation of coke in a heating furnace tube, mainly for the purpose of reducing the viscosity of the raw material, and there are two types: a coil type and a soaker type. Normally, cracked oil leaving the cracking furnace is rapidly cooled to crack it and suppress coke. This includes
Examples include the Lummus method and the Shell method. In addition, the coking method is a process that simultaneously produces coke, but after heating the residual oil in a heating furnace for a relatively short period of time, it is sent to a coke drum.
Here, delayed coking (UOP method, Foster
Wheeler method, MWKellogg method, Lummus method and
CONOCO method, etc.), fluid coking method (Exxon method, etc.) in which residual oil is cracked on high-temperature fluid coke, flexi coking method (Exxon method), which combines fluid coking method with gasification process of coke produced, , the EUREKA process, which produces pitch by thermal decomposition and steam stripping at relatively low pressures such as normal pressure. Among these thermal cracking processes, as a result of the sulfur content and metal content in the residual oil being concentrated in the coke produced, the cracked oil contains relatively few impurities.
Therefore, the coking method is preferable because it requires a comparative vessel for purification even after acid catalyst treatment and contains a relatively large amount of aliphatic olefin with a high boiling point. Furthermore, among these, delayed coking is operated on a large scale because it produces lump coke that is useful as a carbon source for graphite for electrodes, and as a result, it produces particularly large amounts of cracked oil as a by-product. Therefore, it is an advantageous caulking method because the benefits will be great if the present invention makes effective use of it. The composition of the pyrolysis oil obtained from the above pyrolysis process varies depending on the type of pyrolysis process, pyrolysis conditions, type of raw heavy oil, etc., but it usually contains almost all aromatic olefins. In addition to paraffins such as normal paraffin and iso-paraffin, it also contains highly reactive aliphatic olefins such as normal olefin and iso-olefin, and also includes alkyl-substituted monocycles such as alkylbenzene, alkylindanes, and alkyltetralins. It includes aromatic hydrocarbons having an alkyl-substituted complex ring such as, and an alkyl-substituted condensed ring such as alkylnaphthalene. Among the pyrolysis oils obtained from the various pyrolysis processes mentioned above, in the present invention, boiling points of 120 to 290
℃, more preferably a pyrolysis oil fraction whose main component is hydrocarbons in the range of 150 to 260℃. A fraction whose main component is a hydrocarbon having a boiling point outside the above range is not preferred because the yield of the reaction product is poor. Furthermore, the pyrolysis oil fraction to be treated in the present invention needs to contain aromatic hydrocarbons and aliphatic olefins. A fraction containing no aromatic hydrocarbons is not preferred because the resulting reaction product will have a high pour point. It is necessary that the aliphatic olefin be contained in the fraction at 10% by weight or more, and a fraction containing less aliphatic olefin is not preferable because the reaction product cannot be recovered in an economical yield. . The typical composition of the target pyrolysis oil fraction is 30 to 70% by weight of paraffin and 10 to 10% of aliphatic olefin.
40% by weight, aromatic hydrocarbons 5-20% by weight.
However, as long as the above-mentioned conditions for the target fraction are satisfied, there is no problem in appropriately fractionating the pyrolysis oil or diluting it with unreacted oil or the like. As the acid catalyst used in the treatment, solid acid catalysts, mineral acids, so-called Friedel-Crafts catalysts, organic acids, etc. are preferably used. For example, specifically, acid clay minerals such as acid clay and activated clay, amorphous or crystalline silica-alumina, AlF ₃ .
Al ₂ O ₃ , solid acid catalysts such as strong acid type ion exchange resins, HF, AlCl ₃ , BF ₃ . Friedel-Crafts catalysts such as _CnCl4 , inorganic or organic acids such as sulfuric acid, para-toluenesulfonic acid, trifluoromethanesulfonic acid. The reaction format of the treatment may be batch type, semi-batch type or flow type, but when using a solid acid, it is preferable to use flow type. The above-mentioned acid catalyst is added to the fraction in an amount of 0.2 to 20% by weight, preferably 1 to 10% by weight in a batch process, and treated at an LHSV of 0.1 to 20, preferably 0.5 to 10 in a flow process. do. Reaction temperature is 30-330
℃, preferably 50 to 250℃. Although the treatment time varies depending on the reaction conditions, that is, the amount of catalyst, reaction temperature, raw material composition, etc., a sufficient time is required for the reaction to be completed, and can usually be selected within the range of 2 to 24 hours. The reaction pressure may be any pressure necessary to maintain the reaction phase in a liquid phase. In the present invention, the acid catalyst treatment is carried out in such a manner that a reaction product having a boiling point higher than that of the pyrolysis oil fraction and a boiling point of 330° C. or higher is obtained. The reaction product is mainly composed of oligomers of aliphatic olefins and alkylates of aliphatic olefins and aromatic hydrocarbons. The boiling point of the reaction product is 330
℃ or lower than the boiling point of the thermal decomposition fraction, the reaction product is of no industrial value;
Further, the effect of acid catalyst treatment cannot be expected, which is not preferable. In the present invention, as mentioned above, a specific distillate from a specific source is used as a raw material and a specific treatment is performed, so that high molecular weight compounds that adversely affect various physical properties are not substantially generated, and the reaction product of the present invention is It is a liquid material with a relatively low viscosity, for example, 3 to 20 cSt at 75°C. Therefore, after acid catalyst treatment, the unreacted fraction (thermal cracked oil fraction of the starting material) is usually separated by physical separation means such as distillation, without further separating heavier compounds. The reaction product can be used. Of course, the product can also be divided into fractions with appropriate boiling point ranges depending on the use and other purposes. Through the above treatment, the unsaturated content of the pyrolysis oil fraction is reduced, for example, the bromine number is reduced, but the reaction product contains oligomers of aliphatic olefins as described above, so it is preferable. By carrying out a catalytic hydrogenation treatment, unsaturation is further reduced or eliminated while substantially avoiding hydrogenation of aromatic nuclei. The catalytic hydrogenation treatment may also be performed on either the separated reaction product, a fraction containing a large amount of the reaction product, or the mixture itself of the pyrolysis oil fraction subjected to the acid catalyst treatment. be able to. Any conventionally known catalyst can be used for the catalytic hydrogenation treatment. For example, Pt, Pd, Ni, Co,
Metal catalysts such as Mo, W, Co-Mo, and Ni-W can be used. The conditions for this treatment are usually a reaction temperature of 250 to 400°C, a hydrogen pressure of 20 to 100 Kg/cm ² , and a hydrogen/
Oil molar ratio is 0.5-20, LHSV 0.1-10. After the catalytic hydrogenation treatment, reaction products and, if necessary, gas components are separated by appropriate means such as distillation. Of course, depending on the application, the hydrogenation reaction product may be further separated into appropriate fractions. The hydrogenation reaction product thus obtained has a boiling point of 330°C or higher, a viscosity of 25 cSt or lower at 75°C, a pour point of -45°C or lower, and a flash point of 140°C or higher. The composition varies depending on the type of raw petroleum heavy oil, thermal decomposition conditions, etc., but it contains almost no normal paraffins, isoparaffins, alkyl-substituted monocyclic rings, or It consists of aromatic hydrocarbons containing complex rings. In addition, the unreacted oil fraction that remains after the reaction products and added aromatic hydrocarbons are separated and removed from the pyrolysis oil fraction contains a large amount of normal paraffins, and isoparaffins and a small amount of aromatic carbonization. Contains hydrogen. The features of the present invention are summarized as follows. (1) According to the present invention, the cracked oil from the pyrolysis process of heavy residual oil can be utilized to a high degree, and the industrial value is low, and a large amount of surplus heavy residual oil can be effectively utilized. It has great industrial value. (2) That is, the reaction product obtained by the method of the present invention has a low viscosity and a low pour point, and can be used as an inexpensive electrical insulating oil by subjecting it to catalytic hydrogenation treatment if necessary. can. Furthermore, even though heavy residual oil is used as a raw material, electrical insulating oil containing almost no metal content or sulfur content can be obtained. (3) Since the raw material is a fraction of a specific composition from a specific source and subjected to specific processing, products with relatively high viscosity are obtained without substantially producing polymeric substances that would adversely affect physical properties. As a result,
It has the advantage that it can be used only by removing unreacted fractions as appropriate. Next, the present invention will be explained in detail with reference to Examples. Example 1 Delayed coking equipment coking vacuum distillation residue oil with properties shown in Table 1 obtained from Minas crude oil (decomposition conditions: decomposition temperature 496°C, residence time 24
time, decomposition pressure 4Kg/cm ² ), as shown in Table 2,
Pyrolysis oil was obtained along with gas and coke.

【table】

[Table] In this example, fraction 2 of the pyrolysis oil fractions shown in Table 2 was used as a raw material, and its composition is shown in Table 3.

[Table] Next, 40g of AlCl ₃ was added to fraction 2 of 4, and the mixture was heated to 50°C.
The mixture was treated in batches for 20 hours with stirring. After treatment, the reaction mixture was treated with aqueous ammonia and AlCl ₃
was neutralized and decomposed and removed by washing with water. Then dehydrate and 340
Reaction product (870 g, 29% yield) as a fraction at ⁺ °C
I got it. The bromine number of this reaction product was 6.4 cg/g, the aromatic content was 78.7%, and the remainder was mostly olefin oligomers. Subsequently, this reaction product was subjected to hydrogenation treatment using a Cp-Mo catalyst at a hydrogen pressure of 50 Kg/cm ² , a reaction temperature of 280° C., and a ratio of 1 raw oil volume/catalyst volume/hr. After hydrogenation, light components produced by decomposition were distilled off, and the hydrogenated reaction product was recovered. The recovery rate was 92%. This hydrogenated reaction product has a bromine value of 0.34 cg/g and an aromatic content of
It was 76.6%, and nuclear hydrogenation of aromatic compounds did not substantially occur. Physical properties of this hydrogenated reaction product and
Electrical property test based on ASTMD-1934 and JIS
The results of the oxidation stability test according to C2101 are summarized in Table 4. For comparison, Table 4 also shows the results for mineral oil. From the results in Table 4, it is clear that the hydrogenation reaction product of the present invention has superior physical properties compared to mineral oil, and is therefore most suitable as an electrical insulating oil.

[Table] Example 2 Add 40 ml to fractions 2 and 4 of Table 2 obtained in Example 1.
of BF ₃ .H ₂ O was added thereto and treated in batches at 50° C. for 2 hours. The reaction mixture was treated with ammonia aqueous solution, and the catalyst was neutralized and removed by washing with water. After sufficient dehydration, 690 g of the reaction product was recovered as a 350°C ⁺ fraction. The product had a viscosity of 10.2 cSt (75°C), a pour point of -47.5°C and a flash point of 200°C. Example 3 The Minas vacuum residual oil from Example 1 was thermally decomposed under the conditions of a residence time of 1.5 hours, a temperature of 48.5℃, and a pressure of 1.5Kg/ ^cm2 , and the resulting thermal decomposition oil was rectified and heated to a temperature of 100 to 300℃. Pyrolysis oil fraction with a boiling point range of (120-290℃ is 85℃)
%) was obtained. The yield rate was 37%. This pyrolysis oil fraction was treated in a fixed bed flow system using silica/alumina as a catalyst at a reaction temperature of 200° C. and at a ratio of 1 volume of raw oil/amount of catalyst/Hr. The reaction solution is directly exposed to hydrogen pressure using a Co-Mo catalyst.
Catalytic hydrogenation treatment was carried out under the following conditions: 50 Kg/cm ² , reaction temperature 300° C., 1 volume of raw oil/capacity of catalyst/Hr, and H ₂ /oil molar ratio of 10. After the hydrogenation treatment, the reaction product was obtained as a 330°C ⁺ fraction. This hydrogenated product has a viscosity of 5.4 cSt (75
), pour point -52.5°C, and flash point 152°C. Subsequently, the hydrogenated reaction product was also tested for electrical properties and oxidation stability.
Table 5 shows the results. The reaction product of Example 2 at 350° C. ⁺ was also subjected to hydrogenation treatment, and the test results are also shown.

【table】

Claims (1)

[Claims] 1. The main component is a hydrocarbon whose boiling point is in the range of 120 to 290 degrees Celsius obtained by thermally decomposing petroleum heavy residual oil at a temperature of 400 to 600 degrees Celsius, and aromatic hydrocarbons and at least 100 degrees Celsius. A pyrolysis oil fraction containing % by weight of aliphatic olefins was obtained, and this was heated in the liquid phase in the presence of an acid catalyst at a reaction temperature of 30~30°C.
A method for producing electrical insulating oil characterized by producing a reaction product with a boiling point of 330°C or higher by processing at 330°C. 2. The method of claim 1, wherein the pyrolysis process is a coking process. 3 Petroleum heavy residual oil is pyrolyzed at a temperature of 400 to 600°C, and the main component is hydrocarbons with boiling points in the range of 120 to 290°C, and aromatic hydrocarbons and at least 10% by weight of aliphatic olefins. A pyrolysis oil fraction containing
Production of electrical insulating oil characterized by obtaining a reaction product with a boiling point of 330°C or higher by processing at 330°C, and then subjecting it to catalytic hydrogenation treatment under conditions that substantially do not cause nuclear hydrogenation of aromatic hydrocarbons. Law. 4. The method of claim 3, wherein the pyrolysis process is coking.