DE2143972A1 - Process for the production of lubricating oil with an improved viscosity index - Google Patents

Description

Patent assessor Hamburg, August 20th, 1971

Dr. G. Schupfner ??; * ^o gg

Beutsehe Texaco AG <D? J% ⁸ ^> 2143972

2ooo Hamburg? 6 ■ ^{JB / M} ^ Sechslingspforte 2

TEXACO DEVELOPMENiB CORPORATION /

135 East, 42nd Street New York, N.T. 1oo1? UNITED STATES.

Process for the production of lubricating oil with improved viscosity index

The present invention relates to the manufacture of Lubricating oils. In particular, the invention relates to the conversion of low quality lubricating oil feedstock in lubricating oils with a high viscosity index (VI) in good yields.

Up until now it was common to check the viscosity index of lubricating oils , especially of engine oils (crankcase oils), by adding viscosity index improvers. Oils that were given a high viscosity index in this way were suitable for use in automobile engines satisfactory. However, the increased demand for fluids made for automatic transmissions with a wide temperature range and after multigrade engine oils (e.g. 5 w-3o and 1o w-4-o), the, normally would need increasing proportions of viscosity index improvers, it would be necessary to create base oils with higher VI, by the proportion of VI improvers used

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minimize and thereby improve the shear strength. There is currently a great need for lubricating grounds with a relatively high Vl. Satisfying this demand is then not difficult if SchmierälausgangsEtaterialien high _quality% for "B, Fesnsylvania oils are used _t. However, there are not enough oils of such quality available to meet the rapidly growing demand for high VI lubricating oils of lower viscosity grades such as SAE 10 and SAE 20. Thus, it is now necessary _t not only lubricating oil feedstocks lower quality - this is oils having a VI under 8o or even below 75 - having production of oils having a VI of at least about Ήο convert, but also affect the conversion in such a manner and improve »so that no significant reduction in yield occurs.

There are several methods of refining lubricating oil feedstocks known. Usually this is done either by vacuum distillation or by deasphalting a vacuum residue obtained lubricating oil with the help of Solvent extraction to increase VI and, with the aid of solvent dewaxing, to lower the pour point improved. Acid treatment leads to an improvement in color, stability and resistance to oxidation, while the treatment with clay to further improve the color and neutralize the acid treatment -menden oil is carried out. Recently, an intensive catalytic hydrogenation of the oil was used to replace the Solvent dewaxing proposed to achieve an improved VI of the oil.

It is an object of the invention to produce high VI lubricating oils from lower lubricating oil feedstocks Quality. Another object of the invention is to produce high VI lubricating oils from lubricating oil feedstocks lower quality in yields that have not been achieved by previous processes.

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Veiter, it is an object of the invention to produce lubricating oils, which are stable to UV light.

The inventive solution to these problems relates to a Process for the production of lubricating oil with improved viscosity index by solvent extraction and dewaxing, characterized in that the solvent extracted from the lubricating oil feedstock aromatic-rich extract is hydrorefined and at least in part with either the lubricating oil feedstock combined into the solvent extraction zone or with the refined lubricating oil from the solvent extraction zone is passed into the solvent dewaxing zone.

Examples of lubricating oil feedstocks that are considered in the present process, · are petroleum fractions with a viscosity between ^ o and 5oo SUS at 98.9 ° C. Although the method according to the invention is applicable to any lubricating oil starting material, starting materials of medium quality are particularly suitable for a treatment, ie starting materials which have a VI of no more than about 90, in particular starting materials of lower quality with a VI below about 80, with improved Lubricating oils with a VI which is at least 20 units higher than the VI of the starting material can be produced.

Lubricating oil stocks are usually obtained by distillation from crude oil. The starting material can be used as Top product of a vacuum distillation by deasphalting the residue by, for example, the residue with a Deasphalting agents such as propane, butane and similar agents or mixtures thereof are reacted. According to the method according to the invention, the lubricating oil fraction subjected to solvent extraction, the solvent used having an affinity for aromatic Has hydrocarbons. Solvents are particularly suitable such as furfural, phenol, dichloroethyl ether and N-methyl-

-4- * or from the residue of vacuum distillation

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2 - pyrrolidone. Advantageously, the extraction is carried out as countercurrent extraction, wherein the solvent at the head of the extraction tower and the oil near the bottom of the tower and introduced the tower temperature is maintained between about 65 and 121 ⁰ C. The solvent to oil volume ratio can range from about 1 to 6. The oil is removed as raffinate at the top of the tower and is then advantageously treated by heating and stripping with steam to remove solvent residues. Solvent and extract are drawn off at the bottom of the extraction tower and separated by distillation.

The extract is then subjected to catalytic hydro refining at a temperature between about 315 and ⁰

a pressure between about 56 and 352 kg / cm, a space-time velocity, RZG, of about 0.1-5.0 volume oil / volume catalyst per hour and an EU speed between about 253 and 3370 Nm ^ EU / m ^ raw material subject to (15oo and 2oooo standard cubic feet per barrel of charge). The temperature is preferably between 34-0 - 445 ° C, the pressure between 91 and 211 kg / cm ² , the RZG between 0.15 and 1.5 volume / volume χ hour and the Hp speed between 505 and 1685 Nm * ^ / m * starting material (3000 and I0000 SCB ¹ B) set. The gas used for the hydrogenation does not necessarily have to be pure hydrogen. Hydrogen with a purity of at least 65% »preferably at least 75%» can be used.

The catalysts used in hydro refining generally consist of a hydrogenation component on a carrier. The main constituents of the hydrogenation component are metals of group VIII of the PSE or mixtures of metals of group VIII or compounds of these metals such as oxides or sulfides. Examples of metals of group VIII used are nickel, cobalt, iron or mixtures thereof. The metal of the iron group should be in a proportion between about 2 and 40%, preferably 3-15 % (based on the total weight of the catalyst

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sator composition), be present. In conjunction with a metal from the iron group, a metal from group VI of the PSE such as molybdenum or tungsten can be used. In this case the metal is VI. Group in a proportion between about 5 and 40 % (based on the weight of the composition), preferably between 10 and 25% »present.

The hydrogenation component is deposited on a carrier made of a refractory inorganic oxidic material such as aluminum oxide, SiOg, magnesium, zirconium, titanium oxide, crystalline aluminosilicates and similar compounds and mixtures thereof. If the lubricating oil extract introduced into the hydrorefining zone comes from a deasphalted residue and it is desired to convert this extract into a lubricating oil of SAE 1o or SAE 2o, the catalyst advantageously contains an acidic support such as crystalline aluminosilicates of the zeolite Y-type with reduced alkali content, e.g. less than 1.0% by weight, together with a mixture of an amorphous inorganic oxidic material such as 70-90% SiOp and 10-3o% aluminum oxide. If the extract was obtained from a paraffin distillate, the catalyst support has only low cracking activity.

If the catalyst has cracking activity, it is sometimes desirable to suppress this and for this purpose a small proportion of ammonia or CO is added to the hydrogen. A suitable proportion, which depends on the extent of the cracking activity to be suppressed, is in the range between about 0.1 and 2.0 % (based on the reactor gas) ammonia or CO. The catalyst can be used in the form of a slurry, a fixed bed or a fluidized bed. If the fixed bed form is selected, oil and hydrogen can flow upwards or downwards or the hydrogen flows in countercurrent to the downflowing oil. In general terms, the catalysts considered in the process according to the invention are those which have a suitable activity for carrying out the reactions described here. _6_

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These catalysts contain 2 - Ίο% cobalt or nickel and Ίο - 3o % molybdenum or tungsten. Particularly suitable catalysts contain about 6 % nickel and 20 % tungsten or about 5 % nickel or cobalt and about Ί2-Ί5 % molybdenum.

In one embodiment of the invention, the hydro refined Extract treated in a separation stage to remove hydrogen and light distillates and sent to the solvent refining zone returned together with fresh raw material. In another embodiment, the ■ Hydro-refined extract after the separation of lighter materials

-all are combined with the raffinate from the solvent extraction zone ψ and the mixture is subjected to solvent dewaxing.

To pour point improving the oil is _t with a dewaxing example, with a mixture of equal parts of a ketone, for example acetone or methyl ethyl ketone and a aromr.tisehen component, for example benzene or toluene per volume of oil are added in a ratio of about "5-A volumes of solvent The mixture is cooled to about ^ 7> 5 to -3o G, the temperature depending on the desired pour point. The paraffinic components are removed from the cooled mixture by filtration or centrifugation. The dewaxed mixture is then subjected to short path distillation and stripping for solvent removal subject.

The object solution according to the invention also relates to a multistage Hydro refining. If, for example, a 2-stage process is used, a first stage takes place Pre-hydrogenation of the extract, which is particularly suitable for saturating aromatic compounds, and then the hydrogenated product becomes a catalytic one in a second stage Subjected to hydrocracking. Will this particular embodiment applied, the first stage catalyst consists of a conventional hydrogenation component on top of one Carrier such as aluminum oxide, which has minimal cracking activity

ity, while in the second

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Stage a hydrocracking catalyst is used which contains a hydrogenation component on a carrier which is acidic and adapted so that there is a considerable conversion of the product originating from the prehydrogenation zone into compounds of low molecular weight. A catalyst which is used in the second stage can contain 0.1-5 wt. % Platinum or palladium / 0.1-5 wt.% Rhenium on a carrier such as zeolite with a low alkali metal content in admixture with one or more amorphous inorganic oxides, such as mixtures of SiOp and aluminum oxide with 70-90% by weight SiO ₂ and 10-30% by weight aluminum oxide.

In the scope of the invention is also the raffinate treatment, in addition to solvent dewaxing, by hydrofinishing, a hydrating treatment under mild conditions, generally at a temperature of about 2o5 - 34o ° C and at a pressure of around 28 - 1o5 kg / cm, represents. The catalyst used for the hydrofinishing treatment can be the same as that used for the extract prehydrogenation is used, or it is a similar one. The hydrofinishing treatment is particularly used when the hydro-refined extract is combined with the raffinate and is not recycled to the solvent extraction step. The hydrofinishing treatment can be done before or carried out after the solvent dewaxing will. Regardless of the solvent dewaxing sequence and hydrofinishing the hydrofinished extract with the raffinate prior to the solvent dewaxing step united.

The following examples illustrate the invention. Example I.

This example uses a distillate oil with the following properties used as starting material:

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Table 1

Viscosity in SUS / 98.9 ° C 55.7 Viscosity index 77

Pour point, ⁰ C. 35, ο

The starting material was on a catalyst, "consisting of 6 % nickel and 21 % tungsten on a support containing 22% hydrogen-decationized zeolite T, 65% SiO ₀ and 13% aluminum oxide, at 36o G, 127 kg / cm, a RZG of 1.0 and a! ^ - rate of 1o16 Nm ^ Hp / icP starting material. (6ooo SCPB). After the separation of the lighter materials from the lubricating oil fraction, the lubricating oil was dewaxed by mixing it with a 5o: 5o mixture of Methyl ethyl ketone and toluene were mixed, cooled to −23 ° C., the mixture was filtered and the solvents were drawn off ° C to form a product with the YI of 1o7. The properties of the intermediate and end products are given in Table 2:

Table 2

ι »- Hydrogenated
Starting mat Deparaff
. oil . Solution sin.
raff. , ent
paraff. oil Viscosity in SUS / 98.9 C 44.5 45.8 46.5 Viscosity index 114 1oo 1o7 Yield in Vo 1-%
(based on output
material) 84 63 55 Pour point, ⁰ C 37.8 - 15, ο - 15, o

The above example represents a common process by subjecting a lubricating oil fraction to strong hydrogenation, the hydrogenated product dewaxed and the dewaxed one oil to form an oil with the desired VI solvent -extracted vdrd.

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The solution-dewaxed oil is before the solution. Medium refining is unstable to UV radiation, while the solvent refined oil is stabilized.

Example II

This example shows an embodiment of the invention. The starting material was the same as in Example I chosen. However, the procedure differs from that in Example I in that the starting material first solvent extraction with N-methyl-2-pyrrolidone a solvent to oil ratio of 2: 1 and at 82.2 ° C was subjected. The extract was then hydrorefined under the same conditions as in Example I. The hydro-refined extract was then combined with the raffinate and the mixture was mixed with a 5o: 5o - mixture of methyl ethyl ketone and toluene at - 26.1 ° C solvent dewaxed. The results for the intermediate and end products are given in Table 3, where mean:

1: raffinate

2: extract

3: hydro-refined extract

4: raffinate + hydro-refined extract

5: dewaxed oil

Table 3 _Λ 2 3 4 5

Viscosity, SUS / 98.9 ⁰ C 51.6 71, ο 39 44.7 46

Viscosity index 11o 11 1oo 114 1o7

Setting point, ⁰ C 1oo - 6o 9o ο

'Yield in% by volume
(based on starting material) 58 42 34 92 69

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The product of Example II showed good UV stability. It should be noted that the product oils of Examples I and II had essentially the same properties, the yield of Example II being 25 % higher than that of Example I.

Example III

This example is a repetition of Example II with the exception that the hydrogenated extract was not combined with the raffinate but was returned to the solvent extraction zone. In the treatment of the raffinate according to Example II, a product oil similar to that in column 5j of Table 3 was obtained - with the exception that the product oil resulted in a yield of 73 % (based on the starting material).

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Claims (6)

2U3972- T 71 038 (D 71.875) Patent pending Process for the production of lubricating oil with improved viscosity index by solvent extraction and dewaxing, characterized, that the aromatic-rich extract obtained from the lubricating oil feedstock by solvent extraction is hydrorefined is and at least in part either combined with the lubricating oil feedstock in the solvent extraction zone or with the refined lubricating oil from the solvent extraction into the solvent dewaxing zone to be led. 2. The method according to claim 1, characterized in that * z ei c h η e t that the lubricating oil of a hydrofinishing treatment is subjected either before or after dewaxing. 3. The method according to claim 1 or 2, characterized in g e that the hydro refining is carried out in a one-step kataly.fci treatment will. 4. The method according to claim 1 or 2, characterized that the hydro refining is carried out in a two-stage catalytic treatment ■ will. 5. The method according to Αηφruch 3, characterized that a catalyst containing a metal of Group VIII of the PSE or a compound is used Hütalls on a support containing crystalline aluminosilicate with reduced alkali content, 20981 6/1331 2U3972 is used. 6..Verfahren according to claim 4, characterized that in the first catalytic treatment stage mainly an aroma saturation and in the second catalytic treatment stage is mainly carried out a hydrocracking. 7 «Method according to claim 6, characterized that with a hydrocracking catalyst that Contains nickel and rhenium, work is carried out .. 2 0 9 8 16/1331 ORiGiNAL {NSFEC7ED