NL8601742A - METHOD FOR THE PREPARATION OF BASIC LUBRICATING OILS FROM NAPHOLIC FOODS - Google Patents

Description

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K 9432 NET

Process for the preparation of base lubricating oils from naphthenic foods

The present invention relates to a process for the preparation of lubricating base oils from naphthenic feedstocks, as well as to base ash thus prepared.

One of the major problems in the preparation of base oils from naphthenic feedstuffs concerns the presence of naphthenic acids in the feedstuffs to be processed. In order to significantly reduce the amount of naphthenic acids present in the diet, pretreatment is required since these naphthenic acids are unacceptable from the viewpoint of processing and product quality.

Reduction of the amount of naphthenic acids can be achieved by using a conventional clay treatment or a more recent catalytic hydrotreatment, furthermore also considerably reducing the amount of sulfur and nitrogen present in the feed.

Reference is made here to U.S. Patent No.

2,734,019, wherein a naphthenic lubricating oil fraction is treated with a cobalt molybdate catalyst applied to alumina 20 at an elevated temperature and a moderate pressure (well below 60 bar) to yield a product having a significantly reduced sulfur content and a reduced nitrogen content, while the neutralization number has been reduced to almost zero.

It should be noted, however, that the total content of aromatics in the naphthenic feed as described in said US patent, which content is at least 35% by volume, only to a very small extent (ie by about 3-5% by volume). ) by said treatment about * Λ, - * ~ v-> »» * *.

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i * ύ - 2 - the cobalt molybdate catalyst is lowered. As - for various reasons - it is becoming increasingly important to reduce the amount of aromatics in lubricating base oils, in particular those aromatics referred to as polycyclic aromatics as determined by the IP-346 method, to a rather low level - preferably no more than 10 wt.%, it will be apparent that the prior art method leaves much to be desired.

10 It has now been found that naphthenic foods, i.e.

feeds containing both naphthenic acids and a significant amount of aromatics, can be directly (ie, without the need for pretreatment) converted into good quality naphthenic base oils, with a 15 'viscosity index of up to 100 when using certain fluorinated nickel containing catalysts under fairly severe processing conditions.

The present invention therefore relates to a process for the preparation of naphthenic base oils with a viscosity index of at most 100 by catalytic conversion of a naphthenic feed at elevated temperature and pressure in the presence of hydrogen, which process is carried out at a hydrogen partial pressure of at least at least 100 bar in the presence of a fluorinated nickel-containing catalyst which also contains tungsten and / or molybdenum.

By using the specific catalyst and processing conditions of the present invention, it has been found possible to significantly reduce the aromatics content of the feed in a single operation, for example by at least 50 wt% and often by more than 90 wt%, starting from foods containing aromatics in amounts of at least 35% by weight.

It should be noted that the naphthenic feed can - if desired - of course be subjected to a / H -one - *. ~ 9 0 U "- · & -ί - 3 - neutralization pretreatment as mentioned above, in order to substantially reduce the acidic components (while the aromatics remain mainly in the feed), but this is not necessary 5 since the process of the present invention makes it possible to effect a significant reduction in the initial aromatic content as well as complete removal of the acidic components.

The method of the present invention can be advantageously used in the preparation of low viscosity index base oils (which oils are used, for example, as base oils for cutting oils and as carriers for additives) as well as in the preparation of medium viscosity index base oils (which oils for example, be used as base oils for cooler oils, lubricating oils for larger engines, as well as in the preparation of white oil).

Naphthenic base oils with a low viscosity index can now be prepared in much higher yields and with a much lower content of polycyclic aromatics than is possible using a conventional hydrogen treatment and / or acid / clay treatment. It is now possible to reduce the polycyclic aromatics content to over 10 wt% and often to less than 6 wt%, and even 25 to less than 3 wt%, which is of great environmental importance.

Naphthenic base oils with an average viscosity index can now be treated by means of the process of the present invention is prepared in much higher yields than is possible using ordinary solvent extraction from neutralized feeds, if desired, followed by final hydrogen treatment.

In the process of the present invention, both neutralized and unneutralized naphthenic base oil feeds can be suitably used. Preferred foods include non-neutralized naphthenic * = »·; - *) * - - Λ y - 4 - Distillates as they can be converted into valuable naphthenic base oils in one step. The naphthenic distillates to be used may contain at most 4% by weight of sulfur and at most 0.8% by weight of nitrogen compounds. The acid number can be up to 10 mg KOH / g. The naphthenic base oil feeds to be processed usually contain at least 35 wt.% Aromatics and often even more than 65 wt.%.

It is also attractive to use mixtures of two or more (un) neutralized naphthenic distillates as this increases the flexibility in the preparation of different types of lubricating base oils, depending on the composition of the mixture to be processed and the accuracy of the conversion method itself .

The process of the present invention should be performed at a hydrogen partial pressure of at least / 100 bar (10 kPa) and preferably at a pressure between 100 and 200 bar. Temperatures between 280 ° C and 425 ° C can be suitably applied, the use of temperatures between 325 and 400 ° C being preferred, depending - to some extent - on the base oil feed to be processed and the base oil type to be prepared. Usually, the hydrotreating of the present invention will be carried out at a spatial throughput of between 0.1 and 5 kg / kg.hr, especially between 0.2 and 2 kg / kghr.

It has been found that applied to carriers in the process of the present invention. catalysts in addition to nickel must also contain molybdenum and / or tungsten.

The amount of nickel present in the catalyst may suitably vary from 1 to 20% by weight, calculated as oxide on the total catalyst composition, with amounts in the range of 2 to 12% by weight being preferred. The amounts of molybdenum and tungsten can vary from 10 to 40 wt.%, Calculated as oxide on the total catalyst composition, with preference being given to.

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-5- amounts in the range of 10 to 30% by weight. Preferred catalysts contain both nickel and tungsten.

The metals and / or metal compounds can be incorporated into the carriers by any conventional technique such as impregnation, dry impregnation, precipitation and combinations thereof. It is also possible to prepare catalysts by the hydrogel or xerogel method described in British Pat. Nos. 1,493,620 and 1,546,398.

Any suitable support material may be used such as refractory oxides commonly used for hydrotreating catalysts such as silica, alumina, magnesia, zirconia and mixtures thereof. Silica and alumina are preferred carrier materials, in particular alumina. Natural and synthetic crystalline aluminum silicates such as faujasite, especially Y-faujasite, and carriers of the ZSM-5 type can also be used.

The catalysts of the present invention also contain fluorine. The amount of fluorine in the catalysts under operating conditions can vary from 0.5 to 10% by weight, preferably from 2 to 8% by weight, based on the total catalyst. Fluorine can be incorporated into the catalyst by one or more fluorination techniques known in the art. Preference is given to incorporating at least part of the required fluorine into the catalyst by means of an in-situ fluorination. It is advantageous to incorporate almost all required fluorine into the catalyst by means of in-situ fluorination, preferably in the initial phase of the hydrotreating. It is also possible to supply, either in a continuous or interrupted manner, a small amount of fluorine, for example between 5 and 100 ppm, based on the feed, during the hydrotreating. This can be conveniently achieved by adding to the feed to be processed a suitable fluorine compound, for example difluoroethane or o-fluorotoluene. The catalysts can also contain other compounds, such as phosphorus or boron.

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The catalysts can be used in the form of spheres or extrudates. The extrudates can have different shapes depending on the extrusion equipment used during their preparation.

The present invention will now be further elucidated by means of the following examples.

Example 1

An un-neutralized mixture of various naphthenic distillates of South American origin, containing 1.8 wt.% Sulfur, a total nitrogen content of 760 ppm and an aromatics content of 55 wt.%, Including 10.4 wt.% Polycyclic aromatics, was treated with hydrogen at a hydrogen partial pressure of 140 bar at a temperature of 345 ° C and at a spatial flow rate of 0.8 kg / kg.hour over a commercially available fluorinated nickel-tungsten-containing catalyst applied to alumina. Naphthenic base oils were obtained in a yield of more than 95% by weight, based on the starting material. They contain less than 4 wt.% Polycyclic aromatics, less than 250 ppm nitrogen and no more than 0.25 wt% sulfur.

Example 2

An un neutralized mixture of various naphthenic distillates of South American origin, containing 1.8 wt% sulfur, a total nitrogen content of 760 ppm and an aromatics content of 55 wt%, including 10.4 wt% polycyclic aromatics, was treated with hydrogen at a hydrogen partial pressure of 140 bar at a temperature of 360 ° C and at a spatial throughput of 0.8 kg / kg.hour over a commercially available fluorinated nickel-tungsten-containing catalyst on alumina. Naphthenic, 1? U 3 s a / - 7 base oils with less than 2.5 wt% polycyclic aromatics are obtained, while the amount of sulfur is reduced to 0.06 wt% and below, and that of nitrogen to 73 ppm and below. The yield of the naphthenic base oils 5 was 97% based on non-neutralized feed.

Example 3

A non-neutralized naphthenic distillate of South American origin, containing 1.73 wt.% Sulfur, a total nitrogen content of 315 ppm, an aromatics content of 49.8 wt.%, Including 13.7 wt.% Polycyclic aromatics and having a total acid number of 5.7 (mg KOH / g) was treated with hydrogen using the catalyst described in Example 1 at 378eC using the same spatial throughput as described in said Example. A naphthenic base oil with an initial boiling point of 280 ° C and a viscosity index of 45 was obtained in a yield of 59.2% by weight, based on unneutralized starting material.

The base oil obtained contained less than 5 ppm nitrogen and less than 40 ppm sulfur. The total aromatic content was reduced to less than 7% by weight, while the amount of polycyclic aromatics was even less than 1% by weight.

Example 4 An unneutralized naphthenic distillate of

South American origin, containing 2.35% sulfur and 1576 ppm nitrogen, a total aromatic content of 63.9 wt%, including 31.5 wt% polycyclic aromatics, and a total acid number of 7.8, was treated with hydrogen at 30 380 ° C and at a hydrogen partial pressure of 140 bar at a spatial throughput of 0.6 kg / kg.hr. A naphthenic base oil with an initial boiling point of 400 ° C and **. Λ m, f Λ.

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A viscosity index of 35.8 was obtained in a yield of 59.4%, based on non-neutralized starting material. The resulting base lump contained less than 1 ppm nitrogen and no detectable amounts of sulfur. The total aromatic content 5 was 21.8% by weight, of which only 1.8% by weight is attributable to polycyclic aromatics.

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Claims (8)

Process for the preparation of naphthenic base oils with a viscosity index of at least 100 by catalytic conversion of a naphthenic feed at elevated temperature and pressure in the presence of hydrogen, characterized in that the process is carried out at a hydrogen partial pressure of at least 100 bar in the presence of a fluorinated nickel-containing catalyst which also contains tungsten and / or molybdenum. 2. Process according to claim 1, characterized in that a non-neutralized naphthenic feed is used, in particular a naphthenic distillate. Process according to claim 1 or 2, characterized in that the process is carried out at a hydrogen partial pressure of 100 to 200 bar. 4. A method according to any one of claims 1-3, characterized in that a temperature is used in the range from 280 to 425 ° C, in particular between 325 and 400 ° C. 5. Process according to any one of claims 1-4, characterized in that the catalyst used contains between 2 and 20 wt.% Nickel, calculated as the oxide on the total catalyst composition and between 10 and 40 wt.% Molybdenum and / or tungsten, calculated as the oxide (s) on the total catalyst composition. 6. Process according to claim 5, characterized in that a catalyst is used comprising between 2 and 12 wt.% Nickel, calculated as the oxide on the total catalyst composition, and between 10 and 30 wt.% Tungsten, calculated as the oxide on the total catalyst composition. 7. Process according to any one of claims 1-6, characterized in that the catalyst used contains between 0.5 and 10% by weight, in particular between 2 and 8% by weight, of fluorine, based on the total catalyst composition. Process according to any one of claims 1 to 7, characterized in that the catalyst support is silica, alumina, magnesia. Contains zirconia or mixtures thereof, in particular alumina. 0 U} /} £