CA1117057A

CA1117057A - Process for the preparation of a light-stable lubricating oil

Info

Publication number: CA1117057A
Application number: CA000305528A
Authority: CA
Inventors: Emmanuel Neel; Bernard Post
Original assignee: Shell Canada Ltd
Current assignee: Shell Canada Ltd
Priority date: 1977-07-20
Filing date: 1978-06-15
Publication date: 1982-01-26
Also published as: FR2398104B1; GB2001339B; NL7807657A; IT7825851A0; JPS5422412A; DE2831563A1; FR2398104A1; AU518956B2; BE868955A; GB2001339A; AU3812678A; IT1097868B

Abstract

ABSTRACT

PROCESS FOR THE PREPARATION OF
A LIGHT-STABLE LUBRICATING OIL

A process for the preparation of a light-stable lubricating oil by contacting a waxy mineral oil fraction in the presence of hydrogen with one or more supported catalysts containing one or more metals (and/or compounds thereof) of Group VI and/or Group VIII of the Periodic Table of Elements in three subsequent zones, the temperature in the first zone being between 350 and 450°C, the temperature in the second zone being between 310 and 350°C and the temperature in the third zone being between 200 and 325°C, the temperature in the second and the third zone being at least 20°C lower than that in the preceding zone.

Description

~7Q57 PROCESS FOR THE PREPARATION OF
A LIGHT-STABLE LUBRICATING OIL
' The invention relates to a process for the preparation of a light-stable lubricating oil.
Lubricating oils can be prepared by treating waxy ' mineral oil fractions with hydrogen in the presence of a . .
catalyst containing one or more metals (andtor compounds thereof) of Group VI andlor Group VIII of the Periodic Table of Elements at elevated temperatures.
The lubricating oils thus obtained often lack ~-~ sufficient anti-oxidant properties, and to overcome this ~ 10 drawback the oils are conveniently treated in a subsequent '~ second step with hydrogen in the presence of the same or a similar catalyst at a lower temperature than in the first step. The lubricating oils thus obtained have attractive properties in many respects, but they.have an 1lnattractive light stability, which means that when exposed to light a ha~e develops and sludge is formed in a couple of daysO
It has now been found that the light stability of .~
.~ ~

~117~57 these lubricating oils can be tremendously improved by contacting them in the presence of hydrogen with a catalyst which contains one or more metals (and/or compounds there-of) of Group VI and/or Group VIII of the Periodic Table 5 of Elements at a lower temperature than the temperature used in the second step mentioned above.
According to the invention there is provided a process for the preparation of a light-stable lubricating oil . which comprises contacting a waxy mineral oil fraction in the presence of hydrogen with one or more supported catalysts containing one or more metals (and/or compounds thereof) of Group VI and/or Group VIII of the Periodic Table of Elements in three subsequent zones, the temper-ature in the first zone being between 350 and 450C ~ the 15 temperature in the second zone being between 300 and 350C and the temperature in the third zone being between ` 200 and 325C ~ the temperature in the second and the third zone being at least 20C lower than that in the preceding zone.
The waxy mineral oil fraction to be used as starting material for the process of the present invention may be a distillate fraction recovered by vacuum distillation from a residual oil fraction obtained by atmospheric distillation of a mineral oil. The boiling range of such 25 a vacuum distillate is usually between 350C and 550Co Residual fractions, in particular a de-asphalted residue of a vacuum distillation, are also very suitableO Waxes ~1170S7 obtained by dewaxing of a mineral oil fraction, e.g.
slack waxes, may also be used as starting material.
The supported catalyst to be used in the three zones may be the same or different.
Examples of suitable supports for the present catalysts are amorphous oxides of elements of Groups II~
III and IV of the Periodic Table of Elements, such as ; silica, alumina, zirconia, thoria and boria, as well ; as mixtures of these oxides, such as silica-alumina, silica-magnesia and silica-zirconia. Preference is given to catalysts comprising as earrier material alumina. It is further preferred that the eatalysts should have a pore volume of from 0.2 to o.8 ml/g and a surfaee area ` of from 50 to 250 m2/g.
; ~
The catalysts very suitably eontain at least one compound of a metal of Group VI of the Periodic Table of Elements, in particular molybdenum or tungsten, and at least one compound of a metal of Group VIII of the Periodic Table of Elements, in partieular nickel or cobalt. A metal or a compound thereof of the platinum Group may also be used.
The metals may be incorporated into the present catalysts by any one of the techniques for the preparation of multi-component supported catalysts well known in the ; 25 art. The metals are preferably incorporated into the catalysts by co-impregnation of a earrier in one or more steps with an aqueous solution comprising one or more nickel and/or cobalt compounds (nickel compounds being ,~
, ~117~57 preferred) and one or more molybdenum and/or tungsten compounds, followed by drying and calcining. If the im-pregnation is carried out in several steps, the material may be dried and calcined between the successive im-pregnation steps.
The catalysts may also be prepared by incorporating the metals into an alumina hydrogel, and drying and calcining the composition, e.g., as described in French patent specification No. 7,441,351.
Preferably, catalysts are applied which comprise from 1-15%w, in particular 2-10%w nickel, and either 5-20%w molybdenum or 15-35%w tungsten.
, Very suitably the catalysts also comprise a compound of phosphorus and/or fluorine. These elements may be incorporated during impregnation of the carrier with the metal compounds concerned, or they may be incorporated into an alumina hydrogel together with the metals.
Fluorine may also very suitably be incorporated into the catalyst by in-situ fluorination which may be carried out by adding a suitable fluorine compound, such as o-fluoro toluene or difluoro ethane to the gas and/or liquid ,, .
;' stream which is passed over the catalyst.
- The metals may be present on the carrier either as such or as metal oxides or metal sulphides. The catalysts are preferably used in their sulphidic form. Sulphidation of the catalysts may be effected by any one of the techniques for sulphidation of catalysts well known in ', . ~ .

~1~7~)~;7 the art. Sulphidation may, for instance, be carried out by contacting the catalysts with a sulphur-containing gas, such as a mixture of hydrogen and hydrogen sulphide, a mixture of hydrogen and carbon disulphide or a mixture of hydrogen and a mercaptan, such as butyl mercaptan.
Sulphidation may also be carried out by contacting the catalyst with hydrogen and a sulphur-containing hydro-carbon oil, such as a sulphur-containing kerosine or gas oil.
The three subsequent zones with different temper-atures in which the waxy mineral oil fraction is to be contacted with a catalyst may be present in one reactor~
but it is also possible that for two zones or for each zone a separate reactor is used. The effluent from a zone may be used as such as feed material for the next zone~
but it is also possible to remove certain components from the said effluent (e.g., light components by topping) before it is fed to the next zone.
The temperature applied in the third zone is of prime importance for the daylight stability of the oil to be achieved, and very conveniently is to be determined experimentally for any given oil and chosen catalyst.
In general, temperatures from about 250 to about 300C
(e.g., up to 310C) are very suitableO
The hydrogen to be used in the process according to ; the invention may be pure hydrogen, but this is not ~117(~57 necessary. A gas with a hydrogen content of 70% or more by volume is perfectly suitable. In practice it will be preferable to use a hydrogen-containing gas originating from a catalytic reforming plant. Such a gas not only has a high hydrogen content but also contains low-boiling hydrocarbons, for example methane and a small quantity of propane.
The pressure to be used in the process according to the invention may vary between wide limits; the pressure need not be the same in each zone. Pressures lower than 50 bar are less desirable since they reduce the life of the catalysts. Pressures above 250 bar would require cost-ly installations. It is preferable to use pressures between 100 and 200 bar.
The liquid hourly space velocity and the hydrogen/
oil ratios may likewise be selected between wide limits in each zone. Very suitable liquid hourly space veloci-:~ ties are between 0.1 and 10, in particular between 0.5 and 5 kg of oil per litre of catalyst. The hydrogen/
-~ 20 oil ratio is very suitably between 100 and 5000 standard litres per kg of oil.
From the effluent of the third zone light products :~ (if present) are removed by distillation, and if needed this effluent is dewaxed, in order to obtain the desired lubricating oil which may be used as a component of a lubricating oil composition. Such a composition may 1117~57 contain lubricating oils prepared along the same or different routes from different feedstocks and/or additives in order to improve its properties.
As examples of additives may be mentioned light-stability improvers, which may be used to improve thelight stability still further (e.g., 3,3',5,5'-tetra-tertiary-butyl-4,4'-diphenoquinone), anti-oxidants, viscosity index improvers, detergents, anti-wear extreme pressure additives and pour-point depressants.
EXAMPLES
A waxy distillate obtained by distillation from a Middle East crude was contacted at a hydrogen pressure of 140 bar with a catalyst comprising 20%w MoO3, 6.5%w NiO,4.0%w P205, 69.5%w Al203, fluorinated to a fluorine content of 2.5%w, at a temperature of 390C, a space velocity of 1 kg/l/h and a hydrogen/oil ratio of 1500 Nl/kg. The product obtained was subsequently con-tacted at the same hydrogen pressure,space velocity and hydrogen rate with a catalyst comprising 18.7%w MoO3, 3.8%w NiO, 5%w P205, 72.5%w A1203, fluorinated to a fluorine content of 2.5%w, at a temperature of 330C.
The product obtained was topped, dewaxed. It had a viscosity index of 96.5, a VK of 11.69 cS, and a day-; 210 light stability of 2 days.
The daylight stability is determined as follows:
Pyrex ASTM pour-point test tubes containing 30 g of the oil are placed in a compartment maintained at 35 + 0.5C. The test tubes are then irradiated by two fluorescent tubes (Philips TL 40Wt57) and the times taken for sludge formation to occur in the oils noted.
This oil was contacted in the presence of hydrogen with several catalysts at several temperatures and two pressures, and after topping the daylight stability of the products obtained was determined. The experiments were carried out at a space velocity of 0.9 kg!kgh and a hydrogen/oil ratio of 2200 N1/kg.
The Tables 1 and 2 show the results.

Pressure 140 bar Catalyst Temperature,C
, 200 225 250 275 300 ~25 35 1 + 2.8%w F 9 10 10 11 11 9 7

2 6 8 9 11 11 8 8 2 + 108%w F 9 7 13 13 8 6 _

3 8 9 10 10 13 9 _ 3 + 2.0%w F 9 10 9 10 14 8

4 7 8 9 12 8 8 _ .

Pressure 110 bar : Temperature, C

Catalyst 3 7 9 ~ 8 8 Catalyst 1 is an alumina-based catalyst containing 6.5%w NiO and 29.5%w W03. It has a pore volume of 0-65 ml/g and a surface area of 211 m2/g.

Catalyst 2 i5 an alumina-based catalyst containing 6.5%w NiO, 20.0%W Mo203 and 4.0%w P205. The pore volume is 0. 38 ml/g and the surface area 147 m2/g.

Catalyst 3 is an alumina-based catalyst containing 3.8%w ; NiO, 18-9%w MoO3 and 5,7%W P205. The pore ~:, 10 volume is 0. 54 ml/g and the surface area 201 m2/g.

Catalyst 4 is an alumina-based catalyst containing 605%w NiO, 30%w w03 and 6%w B203. The pore volume ls 0.28 ml/g and the surface area 102 m2/g.
:;
All catalysts were sulphided before use by contacting them with a gas oil and hydrogen under reaction condi-tions, The fluorided catalysts were prepared by incorpo~
rating 250 ppm F as o-fluoro-toluene in the feed until the equilibrium concentration of fluorine in the catalyst ,~

11~7Q57 had been established.
: It can be seen from the Tables that the optimum temperatures in the third zone for improving daylight stability are from about 250 to about 300C.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for the preparation of a light-stable lub-ricating oil which comprises contacting a waxy mineral oil fraction in the presence of hydrogen with one or more supported catalysts containing one or more metals (and/or compounds thereof) of Group VI and/or Group VIII of the Periodic Table of Elements in three subsequent zones, the temperature in the first zone being between 350 and 450°C, the temperature in the second zone being between 310 and 350°C and the temperature in the third zone being between 200 and 325°C, the temperature in the second and the third zone being at least 20°C lower than that in the preceding zone.

2. A process according to claim 1, in which the support of the catalyst(s) is alumina.

3. A process according to claim 1 or 2, in which the catalysts have a pore volume of from 0.2 to 0.8 ml/g.

4. A process according to claim 1, in which the catalysts have a surface area of from 50 to 250 m2/g.

5. A process according to claim 1, in which the metals of Group VI of the Periodic Table of Elements are molybdenum or tungsten.

6. A process according to claim 1, in which the metals of Group VIII of the Periodic Table of Elements are cobalt or nickel.

7. A process according to claim 6, in which the said metal is nickel.

8. A process according to claim 1, in which the catalysts comprise from 1-15%w nickel, and either 5-20%w molybdenum or 15-35%w tungsten.

9. A process according to claim 1, in which the tem-perature in the third zone is from about 250°C to about 300°C.

10. A process according to claim 1, in which the pressure is between 100 and 200 bar.

11. A process according to claim 1, in which the liquid hourly space velocity is between 0.1 and 10 kg of oil per litre of catalyst and the hydrogen/oil ratio is between 100 and 5000 litres per kg of oil.

12. A process according to claim 8, in which the amount of nickel is 2-10% by weight.