CS210908B1 - Method for preparation of basic oil with increased stability - Google Patents

Description

BACKGROUND OF THE INVENTION The present invention relates to a process for the preparation of a base oil or a component for a base oil having an increased oxidative thermal sintering for the preparation of quality oils operating at higher and high operating temperatures.

One of the raw materials or components of the base petroleum oils is hydrogenated oil fractions produced by hydrogenation or cracking of vacuum distillates or propane deasphaltizates from 3 to 30 MPa, temperatures from 300 to 450 ° C, volumetric velocities of 0.3 to 3 hours ^* in the presence hydrogen on hydrogenation or hydrocracking catalysts or mixtures thereof. The catalysts contain metals VIII. and VI. groups on carriers such as alumina, synthetic or natural aluminosilicates or alumina with the addition of acidic components such as fluorine, phosphorus, boron, diatomaceous earth and the like.

By suitably selecting technological conditions, i.e., pressure, volumetric velocity, catalyst and the like, hydrogenated oils can be prepared with optimum physicochemical properties, such as viscosity, viscosity index, as well as oxidation-thermal stability. Hydrogenated oils are relatively easy to prepare with a higher viscosity index compared to selective raffinates and then have very good low temperature viscosity properties. Another advantage of hydrogenated oils is their lower resistance compared to selection raffinates of the same viscosity. These properties are particularly advantageous for the preparation of all-season automotive motor oils and hydrogenated oils are a sought-after raw material for these purposes.

Hydrogenation of the hydrocracked starting oil raw materials under the above conditions results in deep grains in the hydrocarbon composition and grains in the structure of the parent materials. In addition, the sulfur, nitrogen and oxygen compounds are deeply refined and, as a result, the oil produced contains virtually no so-called natural inhibitors which would increase its oxidative stability. Such deeply refined oils usually have a very good susceptibility to additives. When preparing hydrogenated oils, it is important that the finished oil has a minimum content of more nuclear aromatic hydrocarbons (polyaromatates) and polar substances. It is known that these substances, although present in small or trace concentrations, are a source of instability of the hydrogenated oil, or are very reactive. The instability of hydrogenated oil is manifested, for example, by the loss of asphaltene deposits due to sunlight or by the formation of resins and asphaltenes during oxidation or thermal stress of the oil, especially at higher temperatures similar to those affecting oil when used in diesel and petrol engines.

In addition, hydrogenated oils, due to their alkano-cyclenic nature, do not dissolve well the aromatic oxidation products, which then deposit on the walls and internal parts of the engine and change to paints and carbon for longer. This leads to rapid clogging of the engine and shortening of its duty cycle.

Reducing or eliminating polyaramatic undesirable substances in hydrogenated oil to a minimum level is not easy and requires precautions such as increasing hydrogen pressure or processing at low feed rates, which is uneconomical and, as a result, the process becomes unprofitable. An important role is also played by the catalyst, which can favorably influence the pressure or volume rate used in the preparation of hydrogenated oils.

In addition, the optimum hydrocarbon composition of hydrogenated oils is difficult to achieve and a number of methods are described in the technical and patent literature which additionally reduce the content of polyaromatic and mellostable substances in the oil. These are, for example, the process of reacting hydrogenated oil with hydrogen under pressure in the presence of special catalysts containing platinum or palladium, further hydrogenating the degradation of multinuclear aromatic hydrocarbons.

Other processes are based on the removal of these compounds by extraction with selective solvents such as phenol, furfural and the like, thereby increasing the stability of the hydrogenated oil. Methods utilizing the high reaction capability of multinuclear aromatics are also disclosed. The action of unsaturated hydrocarbons on the hydrogenated oil in the presence of acidic catalysts alkylates these aromatic hydrocarbons and converts them to stable alkylaromates. Hydrogenated oils treated in this way have better oxidation and heat stability as well as a higher susceptibility to additives. By adding antioxidants and detergent and dispersant additives, they can be used to form very stable, high temperature resistant lubricating oils. The use of these additional processes means, but introducing other technological processes into production, increasing operating and investment costs, and reducing oil yield, and is therefore less advantageous.

It has now been found that reducing the content of multinuclear aromatic hydrocarbons and polar substances by modifying the basic hydrogenated oil production processes or by introducing additional processes alone does not produce optimal results in terms of oxidation-thermal stability.

A process for preparing a base oil having enhanced oxidation-thermal stability or base oil components for the preparation of automotive or other highly oxidatively heat-stressed oils, from hydrogenated oil having a viscosity index of 70 to 130, prepared by hydrogenation treatment of vacuum distillate in the presence of hydrogenation or hydrocracking catalysts at a pressure of 5 to 30 MPa and temperatures of 300 to 400 ° C, a volumetric rate of 0.3 to 3.0 hr ^-1 and further treatment of the hydrogenate by distillation, dewaxing or doraphina, The process of claim 1, wherein, in addition to the lower boiling fractions, oil fractions having a viscosity of less than 3 to 7 mm 2 / seo are distilled off from the product prepared by the hydrotreating of the vacuum distillate or propane deasphaltizate. at 100 ° C, preferably less than 3 to 5 mm 2 / sec. at 100 ° C further, the oil is worked up in a known manner.

So far, in order to achieve a certain stability of the oil hydrogenates, their degree of refining has been deepened, i.e. the viscosity index has increased, the content of undesirable aromatic hydrocarbons, in particular polyaromatics and polar substances, has been reduced. Generally, achieving deeper oil hydrogenate refining requires producing it at higher pressure, lower bulk velocity, and achieving a higher viscosity index. This makes oil hydrogenate production expensive and uneconomical despite the higher hydrogen consumption. By combining the process of increasing the stability of hydrogenated oils by separating the low viscosity fractions of the invention with the preparation of hydrogenates with a certain degree of refining, as required by the degree of oil stability, very stable hydrogenated oils can be prepared without the need to prepare enormously refined oil hydrogenates. Similarly, this procedure can be used where other processes such as selective refining, hydrogenation refining, acid refining or clay refining are used for the refinement of the hydrogenates.

Most of the low-viscosity fractions were produced as a product of hydrogenation, hydrocracking isomerization of high-boiling fractions and their oxidation stability at high temperatures above 180 ° C is poor. Oxidation of these fractions gives rise to asphaltic substances which are difficult to dissolve in the base oil and cause the formation of varnishes and carbonates in engines, especially on temperature-exposed parts of the engine such as the first piston ring area, piston etc. When low viscosity hydrogenated oil fractions are present, the raffinates are difficult to use with additives, require disproportionately high additive concentrations and do not always produce the desired effect.

This stabilization is expensive and increases the cost of the oil.

Low-viscosity fractionated and refined hydrogenated oils have proven to be very stable at higher temperatures and are suitable either alone or in combination with selective refineries, as base oils for the preparation of automotive engine oils meeting demanding specifications such as the CC-SD group, according to API specification. As the viscosity of the distilled low-viscosity fractions increases, the stability of the residual hydrogenated oil increases. However, the most pronounced improvement in stability is achieved by separating fractions with a viscosity of less than 3 to 5 mm 2 / sec. at 100 ° C.

Example

1. A sulfuric paraffinic petroleum vacuum distillate with a pour point of +40 ° C, a viscosity of 11.8 mm ² / s at 100 ° C was hydrogenated at a pressure of 20.8 MPa, a temperature of 408 ° C, a flow rate of 0.65 h ^{- 1} on a nickel-tungsten catalyst containing 8.5% NiO and 26.0% on active alumina. After the depressurization, the hydrogenated product was distilled to gasoline, kerosene, gas oil, light hydrogenated oil fraction, and a flash point of 214 ° C. The residue yield was 62 wt. The residue was solvent-dewaxed with acetone-benzene-toluene and an oily hydrogenate having a freezing point of -16 ° C was produced. Oil hydrogenate properties after dewaxing:

viscosity at 1 00 ° C 7.19 mm ^ / s viscosity index 99.6 flash point 214 ° C refractive index η ^ θ 1.48 aromatically bonded carbon content 8.6% triaromethy content 1.15 fe

The triaromethy content was determined by calculation from the ultraviolet spectrum of the oil according to the method described by N. Moseacu (Revista de Chemie, 26, 342-346, 1975). For hydrogenated oil, the oxidation stability was determined by IP 48/68 method at which the oil is oxidized at 200 ° C. ° C with air passage for 2x6 hours. It has been found that the oxidation stability of hydrogenated oils is best characterized by the amount of pentane insoluble substances (LNP) contained in the oil after oxidation. The sample was found to be 2.20 fc wt. after oxidation.

The dewaxed oil hydrogenate was subjected to additional distillation and distilled off in the first case of a low viscosity fraction with a viscosity below 3.8 mm ² / s at 100 ° C for a total of 9.5 wt. and in the second case a low-viscosity fraction having a viscosity below 5 ^ 2 mm ² / s at 100 ° C in total 18.6 wt%. The properties of the oil hydrogenates after distillation of the low-viscosity fractions were as follows:

Ί AND II viscosity 100 ° C mm ² / sec 7.65 8.24 viscosity index 102.5 104.5 point of ignition Noc: 2 ° C 230 235 refractive index '20 ⁿ D 1.4790 1, 4785 aromatic carbon content C _A % wt. 8.5 7.6 triaromethyl content % wt. 1,25 1, 20 oxidation stability: LNP content after oxidation % pot ^ 1.40 0.96

The LNP content decreased by distilling off low-viscosity frequencies by 37 and 64% compared to the original oil hydrogenates. In another case, the hydrogenated product was distilled off at atmospheric-vacuum distillation after leaving the reaction zone and depressurized with better separation between the light oil fraction and the residue. The residue yield was 60.5%. The hydrogenate did not contain low-viscosity fractions with a viscosity below 5.0 mm ² / s.

The properties of the oil after dewaxing at a freezing point of -16 ° C were as follows:

viscosity at 100 ° C viscosity index flash point aromatic carbon content C _A triaramate content oxidation stability IP 48/68: LNP content after oxidation xxx by 7.8 mm / s

100.1-232 ° C

8.3% wt. 1.2% wt.

0.85% wt.

Efficient distillation of the product, in which the low-viscosity fractions remained in the light oil fraction and did not transfer to a residue, substantially improved the oxidative stability of the oil and thereby increased its utility value.

2. A vacuum oil distillate from a broad paraffinic petroleum of the same properties as in the first example was hydrogenated at 20.5 MPa, 415 ° C, 0.35 0.35 vol. After releasing the pressure, the hydrogenated product was distilled to gasoline, kerosene, gas oil, light hydrogenated oil fraction and a flash point of 212 ° C. The residue yield was 46 wt%. The residue was solvent-dewaxed for a longer time and an oily hydrogenate was produced with a pour point of -16 ° C.

The properties of oil hydrogenates (I) after dewaxing and its oxidation stability are shown in the table. The hydrogenate elevates the viscosity index and is more refined than the oil hydrogenate mentioned in the first example. By reducing the content of the triaromeths followed by deeper refining at a lower bulk velocity, the oxidative stability of the oil was improved. By distillation into narrow fractions, the oil was found to contain low-viscosity fractions with a viscosity of less than 3.0 am ² / s at 100 ° C. Low viscosity frequencies were distilled off in the first case 8 with a viscosity below 4.0 mm ² / s (hydrogen II) and in the second case with a viscosity below 4.8 mm ² / s (hydrogen III). 16.5 wt. and 24 wt. fractions. The properties of the purified hydrogenates after distillation of these fractions are shown in the table. After separation of the low-viscosity fractions, oxidation stability improved significantly.

In another part, the hydrogenated product was distilled off after leaving the reaction zone and after releasing it from atmospheric-vacuum distillation with a better separation capability between the light hydrogenated fraction and the residue. A residue was prepared with a flash point of 230 ° C and a yield of 40 wt%.

Table!

Dewaxed hydrogenate Dewaxed hydrogenate Dewaxed hydrogenate After distilling off fractions i elhkýoh  AND II III IV Viscosity 100 ° C mm ² / s 5.87 6.10 6.45 6.15 Viscosity index 111.5 113 1’4 112 Flash point ° C 212 225 229 228 ^ 20 ^nD 1, 4730 1,4725 1,4728 1, 4720 Content of aromatic carbon C _A % wt. 4.2 4.1 3.9 4.0 Content of triaromates% wt. 0.85 0.78 0.70 0.75 Oxidation stability: LNP content after oxidation% wt. 1.10 0.65 0.0 0.13 3. Medium vacuum distillate with viscosity 2 10.4 mm / s at 100 ° C, pour point +38 ° C was hydrogenated at 30 psi, 415 ° C, volumetric rates of 1.1 hr ^- to nickel- molybdenum catalyst containing 22.4 MoO 2 and 6.5% NiO per active alumina, Hydrogen-

After cooling and depressurization, the capillary product was distilled to a fuel fraction, a gas oil, a light oil fraction, and a residue having a flash point of 222 ° C. The residue yield was 64.5. The laboratory distillation of the residue to narrow fractions was found to contain fractions with a viscosity lower than 3.0 mm ² / s at 100 ° C.

A portion of the residue having a flash point of 222 ° C was dewaxed in a solvent solvent to obtain an oil with a freezing point of -18 ° C. The oil properties are given in Table 2 (I). Part of the residue was subjected to additional selective phenol refining at 75-85 ° C with a 2: 1 ratio of phenol to oil and a water content of 5% in phenol before solvent dewaxing. The hydrogenated residue after selective refining was solvent dewaxed and an oil having a freezing point of -18 ° C was prepared. The oil properties are given in Table 2 (II). Extraction with phenol removed some of the aromatic hydrocarbons, reduced the content of C _A and the content of triaromates.

Oxidation stability improved and LNP content decreased by more than 50%. The hydrogenated oil was distilled under reduced pressure and a low-viscosity fraction with a viscosity of less than 4.5 mm ² / s was distilled off at 100 ° C. A total of 20.5 wt. fractions. The properties of the treated oil and its oxidation stability are shown in Table 2 (III). Further, the oxidation stability of the oil was significantly improved by distilling off the low-viscosity fraction.

Table2

Hydrogenated Hydrogenated Hydrogenated selectively oil selectively-refined oil to final oil distillate low viscosity fraction__ ^I

I U_III

Viscosity at 100 ° C Viscosity index Flash point ° C

Refractive index n ^

6.5

100.8

222

1.4845

6,3 6,8

106.5 108.5

220 232

1.4770 1.4760

Hydrogenated oil

Hydrogenated selectively refined oil

Hydrogenated selectively refined oil after distilling off the low-viscosity fraction

II

III carbon C _A triaromate content LNP content after oxidation

% hm. 13.6 7.1 6.7 % hm. 2.1 0.40 0.35 48/68: % hm. ’, 9 0.9 0.0

Λ

Propane fourth deasfaltizét viscosity 28.5 mm / s at 100 C under a pressure hydrokrakoval 25 MPa, temperature of 390 ° C, space velocity of 0.6 h ^-1 to nickel-tungsten catalyst on a carrier synthetic aluminosilicate. The hydrocracking liquid product, after cooling and depressurization, was distilled to atmospheric-vacuum distillation to give gasoline, gas oil, low viscosity oil fractions and a flash point of 224 ° C. The residue yield was 70 wt. Laboratory distillation of the residue into narrow fractions was found to contain fractions with a viscosity below 4.0 mm ² / s at 100 ° C.

The residue with a flash point of 224 ° C was dewaxed in solvent and an oil with a freezing point of -12 ° C was prepared. The properties of oil I and its oxidation stability are shown in Table 3. The dewaxed residue was subjected to further distillation at which it was distilled off

0 A all low-viscosity fractions having a viscosity of less than 6.5 mm / s at 100 ° C, total 18% wt. The properties of oil II after distillation of the low-viscosity fraction are shown in Table 3.

Table 3

Odparafinovaný hydrog. deasfaltizét Hydrogenated daasphalti · no low viscosity fraction AND II Viscosity at 100 ° C mm ² / s 11.5 12.4 Viscosity index .93 96 Flash point ° C 225 245 20 ⁿ D • 1.4810 1,4805

Content aromatically bound

of carbon C _A % hm. 6.5 5.6 Content of triaromates % hm. 0.45 0.35 Oxidation stability :. LNP content after oxidation % hm. 0.50 0.0

5. Hydrogenated dewaxed oil I of Example 2 was refined with active clay at 200 ° C. 1% by weight was used for refining. active clays. Oxidation stability, resp. LNP content after oxidation of doraffinated hydrogenate increased to 1.45 wt%. bddistillary low viscosity fractions with a viscosity below 4.1 mm ² / s at 100 ° C from 18% doraffinated oil hydrogenate improved the oxidation stability of the oil and reduced the LNP content after oxidation to 0.45 wt%.

Claims (1)

SUBJECT OF THE INVENTION A process for preparing a base oil with increased stability or a base oil component for the preparation of automotive or other high oxidation-stressed oils from hydrogenated oil having a viscosity index of 70 to 130 prepared by hydrotreating vacuum distillate or propane deasphaltisate hydrogenation and / or hydrocracking catalysts at a pressure of 5 to 30 MPa and a temperature of 300 to 450 ° C, a volumetric rate of 0.3 to 3.0 h ^-1 and further treatment of the hydrogenate by distillation, dewaxing or refining, characterized in that by hydrotreating the vacuum distillate or propane deasphaltizate, in addition to the lower-boiling fractions, all oil fractions with a viscosity of less than 3 to 7 mm ² / s at 100 ° C, preferably less than 3 to 5 tnm ² / s at 100 ° C are separated; processes knows my way.