JPH0434245B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing electrical insulating oil by treating a pyrolysis oil fraction from a pyrolysis process of 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, high sulfur content and high 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 a liquid product, namely 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 automatic gasoline as it was, 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 specific to low temperatures from a large amount of pyrolysis oil fraction obtained as a by-product, which has no utility value other than fuel for boilers, for example in the coking process. The aim is to achieve a high degree of effective utilization of heavy residual oil. That is, according to the present invention, heavy petroleum residual oil can be
By treating a mixture of pyrolysis oil fraction obtained by thermal decomposition at temperatures above 400°C but not exceeding 700°C and aromatic hydrocarbons with a boiling point below 150°C with an acid catalyst, it can be used as electrical insulating oil. Useful reaction products are obtained. Next, the present invention will be explained in further detail. 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. The decomposition temperature of the thermal decomposition process of the present invention must be 400°C or higher and not exceed 700°C.
No thermal decomposition occurs at decomposition temperatures lower than 400℃;
Furthermore, when the temperature exceeds 700℃, aromatic hydrocarbons, which are themselves highly reactive, become excessive in the resulting pyrolyzed oil regardless of the decomposition time, and high polymers such as resin components are lost in 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 400-600°C, more preferably
The temperature is 400-550℃. 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, ranging from reduced pressure to about 50 kg/cm ² . 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 of thermally decomposing the raw material mainly to reduce the viscosity of the raw material under relatively mild conditions while suppressing the generation of coke in a heating furnace tube, 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 Lumnus
There are laws such as the Shell Law and the Shell Law. In addition, the coking method is a process that co-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, Lumnus method and
CONOCO method, etc.), fluid coking method that thermally decomposes residual oil on high-temperature fluid coke (Exxon method, etc.), and flexi coking method (Exxon method), which combines fluid coking method with gasification process of the coke produced. There is also 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 is 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 of the above range is not preferred because an industrially useful reaction product cannot be obtained. Furthermore, the pyrolysis oil fraction to be treated in the present invention needs to contain aliphatic olefins. 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. In the present invention, (A) the above-mentioned pyrolysis oil fraction 20~
95% by weight and (B) 80 to 5% by weight of one or more aromatic hydrocarbons with a boiling point of less than 150°C in the presence of an acid catalyst in the liquid phase at a reaction temperature of 30 to 330°C. By doing so, a reaction product with a boiling point of 260°C or higher is produced. Aromatic hydrocarbons without aliphatic double bonds (B) include benzene, toluene, xylene, and ethylbenzene. 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,
Solid acid catalysts such as AlF ₃ / Al ₂ O ₃ , strong acid type ion exchange resins, Friedel-Crafts catalysts such as HF, AlCl ₃ , BF ₃ , CnCl ₄ , sulfuric acid, para-toluenesulfonic acid, trifluoromethanesulfonic acid, etc. inorganic or organic acids. 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 the flow type. The above-mentioned acid catalyst is added to the fraction in a batchwise manner in an amount of 0.2 to 20% by weight, preferably 1 to 10% by weight.
In addition, in the flow type, the LHSV is 0.1 to 20, preferably 0.5 to 10. Reaction temperature is 30~
The temperature is 300°C, preferably 50-250°C. 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. The above acid treatment produces a reaction product with a boiling point of 260°C or higher. The reaction product is mainly composed of oligomers of aliphatic olefins and alkylates of aliphatic olefins and aromatic hydrocarbons. however,
When an excessive amount of a fraction containing aromatic hydrocarbons is mixed and treated, alkylbenzene, which is an alkylate, becomes the main component in the reaction product. The boiling point of the reaction product will inevitably be higher than the boiling point of the thermally cracked oil fraction due to the above reaction, but if this is lower than 260°C, the reaction product will have no industrial value, and the effect of acid catalyst treatment will be reduced. I don't like it because I can't expect much either. 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, unreacted fractions (thermal cracked oil fractions of starting materials) and aromatic hydrocarbons added and mixed are usually separated by physical separation means such as distillation. The reaction product can be used as electrical insulating oil without separation of heavier compounds. Of course, the various products can also be divided into fractions with appropriate boiling point ranges, if necessary. 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 performing a catalytic hydrogenation treatment, unsaturation is reduced or eliminated without substantially carrying out nuclear hydrogenation of aromatic nuclei. In addition, the catalytic hydrogenation treatment must be performed on either the separated reaction product or 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. I can do it. 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, if necessary, the hydrogenation reaction product may be further separated into appropriate fractions. The hydrogenation reaction product thus obtained has a boiling point of 260°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. 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 can be used as an inexpensive electrical insulating oil with excellent low-temperature properties by appropriately subjecting it to catalytic hydrogenation treatment. Moreover, electrical insulating oil with low unsaturated content, metal content, sulfur content, etc. can be obtained. (3) Since the raw material is a distillate with a specific composition from a specific source and undergoes specific processing, it produces virtually no polymers that would adversely affect physical properties, and produces products with relatively low viscosity. can get. Therefore, depending on the application, it has the advantage that it can be used as an electrical insulating oil by simply removing the unreacted fraction. 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 1 Heavy residual oil properties Minas vacuum residual oil Specific gravity (15℃) API 20 Asphaltene wt% 2.6 Conradson residual carbon wt% 7.1 Table 2 Yield yield (wt%) Butane and light gas 8 30-160℃ (distillate 1) 13 160-260℃ (Fraction 2) 22 260℃ ⁺ (Fraction 3) 40 Coke 17 Total 100 In this example, Fraction 2 of the pyrolysis oil fractions in Table 2 above was used as a raw material. Its composition is shown in Table 3.

[Table] Aromatic olefin content -

Claims (1)

[Scope of Claims] 1 (A) A pyrolysis oil fraction obtained from a pyrolysis process in which petroleum-based heavy residual oil is pyrolyzed at a temperature of 400°C or higher but not exceeding 700°C, which has a boiling point of 120 to 290°C. ℃
20 to 95% by weight of a pyrolysis oil fraction containing hydrocarbons in the range of 20 to 95% by weight and containing aliphatic olefins.
and (B) one or more aromatic hydrocarbons having a boiling point of less than 150°C and having no aliphatic double bonds.
5% by weight in a liquid phase in the presence of an acid catalyst at a reaction temperature of 30 to 300°C to produce a reaction product with a boiling point of 260°C or higher. 2. The method of claim 1, wherein the pyrolysis process is a coking process. 3 (A) A pyrolysis oil fraction obtained from a pyrolysis process in which heavy petroleum residual oil is thermally decomposed at a temperature of 400°C or higher but not exceeding 700°C, with a boiling point of 120 to 290°C.
20 to 95% by weight of a pyrolysis oil fraction containing hydrocarbons in the range of 20 to 95% by weight and containing aliphatic olefins.
and (B) one or more aromatic hydrocarbons having a boiling point of less than 150°C and having no aliphatic double bonds.
5% by weight in the presence of an acid catalyst in a liquid phase at a reaction temperature of 30 to 300°C to produce a reaction product with a boiling point of 260°C or higher, and then nuclear hydrogenation of aromatic hydrocarbons is carried out. A method for producing electrical insulating oil, characterized by carrying out catalytic hydrogenation treatment under conditions that do not substantially generate hydrogenation. 4. The method of claim 3, wherein the pyrolysis process is a coking process.