FR2466499A1 - METHOD FOR MANUFACTURING HIGH VISCOSITY VISCOSITY HIGH VISCOSITY MINERAL OILS WITH IMPROVED VOLATILITY AND OXIDATION RESISTANCE - Google Patents

Abstract

The invention relates to a process for the manufacture of mineral oils with a high viscosity index, low viscosity, with improved volatility and oxidation resistance, comprising vacuum distillation, selective solvent extraction, dewaxing and optionally a treatment of finishing, in which is interposed between the step of extraction by selective solvent and the step of dewaxing, a step of mild catalytic hydrogenation of the raffinate. The catalytic hydrogenation according to the invention is carried out at a temperature between 310 and 450 degrees C, under a pressure between 30 and 100 bars of pure hydrogen with a space velocity between 0.25 and 3, the flow rate ratio of hydrogen under normal temperature and pressure conditions at the hydrocarbon flow rate at 20 degrees C being between 100 and 500. The catalyst used preferably contains oxides of molybdenum and nickel or of molybdenum and cobalt on a support d alumina. The oils obtained according to the process of the invention are used in particular as industrial oils, but above all as motor oils known as “energy saving oils”.

Description

The present invention relates to a process for producing oils

  High Viscosity Mineral Minerals, Low Viscosity and Isoviscosity Volatility and Resistance

  improved oxidation compared to conventional oils.

  paraffinics. To meet the requirements of lubricating oil users, manufacturers of mineral oils have been required to produce oils characterized by a low viscosity variation as a function of temperature (oils with a high viscosity index: VI). In addition, certain applications require good resistance to oxidation of

oils and low volatility.

  The oxidation resistance of an oil makes it possible to use

  the latter in an oxidizing atmosphere and at temperatures

  relatively high levels without the appearance of acidic compounds of degradation often very corrosive and

  precursors of gums and insoluble-undesirable compounds.

  The volatility of an oil is related to the departure, under the effect of the temperature, of light components initially present in the oil. This phenomenon causes loss of lubricant harmful to the user but also in some cases, it can significantly change the viscosity of

the oil in the crankcase.

  For oils prepared according to the usual refining processes, there is a relationship between the viscosity of the oil obtained and its volatility. This increases when the viscosity decreases. It is therefore difficult to obtain a fluid mineral oil with low volatility. However, the current trend for engine lubrication, for example, is to use low-viscosity oils with a

  high viscosity index and very low volatility.

  This is the generation of oils called "energy saving oils". They make it easier for the engine to start cold and prevent oil loss by evaporation in the engine. Synthetic lubricants prepared from diesters and poly-olefins have the characteristics required by energy saving oils

  but their manufacture is expensive.

  Processes for the preparation of viscous high viscosity fluids from petroleum fractions are already known. For example, it is possible to prepare such oils by vacuum fractionation of a hydrocracking residue followed by dewaxing. In some cases,

  the fraction of the hydrocracking residue is pretreated

  with a selective solvent (furfural, phenol). Another method is to hydrogenate a petroleum fraction severely, then subject it to selective solvent treatment and dewaxing. Finally, while retaining the sequence of steps of the usual process for the preparation of lubricants: vacuum distillation, solvent extraction, dewaxing, finishing treatment, it is possible to obtain fluid oils with a high viscosity index, by increasing the severity very significantly. treatment

with the selective solvent.

  All these processes have the drawback of giving oil yields with respect to the distillates or

  relatively low hydrocracking residue.

  The Applicant has now discovered that if, between the selective solvent extraction step and the dewaxing step, a sweet raffinate hydrogenation step is interposed, it is possible to prepare with high yields high lubricants. Viscosity index, low viscosity, low volatility and improved oxidation resistance. The object of the present invention is therefore a

  moderate catalytic hydrogenation of raffinates.

  The lubricants prepared according to the invention have, at isoviscosity, a lower volatility than those prepared

  by treatment with solvent under severe conditions.

  According to the present invention, the various fractions obtained from the vacuum distillation are subjected to a solvent extraction, and the raffinate is hydrogenated under moderate pressure and temperature conditions, the temperature being not exceeded. However, the hydrocracking is greater than 310 ° C., and the hydrogenated fraction is subjected to

  dewaxing and possibly to a finishing treatment.

  Solvent extraction, dewaxing treatments

  and finishing are the processes of extraction, deparaffi-

  swimming and finishing known to date. These are mainly

  conventional processes used in production chains

oil.

  Selective solvent treatment (furfural or phenol) removes unwanted compounds, mainly

  polyaromatic and aromatic sulfur compounds. The hydro-

  The following genesis will therefore, above all, affect mono-

  or diaromatic and sulfur compounds remaining in the raffinate. The flexibility of the hydrogenation process makes it possible, while minimizing the proportions of sulfur compounds that inhibit oxidation, to restore an optimum equilibrium.

  sulfur / aromatic compounds essential for good resistance

  oxidation of the hydrogenated oil. The process according to the present invention thus makes it possible to treat petroleum fractions originating from crude with a high sulfur content and to obtain in good yields bases for lubricants containing very little sulfur but having good resistance.

to oxidation.

  For optimal implementation of the process according to the present invention, the catalytic hydrogenation of the raffinates is carried out under the following conditions: at an average temperature of between 310 and 450 ° C., preferably between 380 and 4000 ° C., under a pressure of between and 100 bar of pure hydrogen, preferably equal to or greater than 35 bar - with a space velocity of between 0.25 and 3 and preferably between 1 and 1.5 volume of feed per volume of catalyst per hour, the ratio of hydrogen flow under the conditions

  temperature and pressure at the hydrocarbon flow rate.

  at 200C being between 100 and 500.

  The catalyst used is a hydrogenation catalyst for aromatic hydrocarbons. It contains a Group VI metal and one or more Group VIII metals deposited on an alumina support. Catalysts which are particularly suitable for carrying out the process according to the invention include those containing molybdenum and nickel oxides or molybdenum and cobalt oxides. An example of a catalyst formulation can be Mo 03 14% by weight Ni 0 3% Alumina support In the implementation of the method, according to the invention, the catalyst is activated by a sulfur compound according to the conventional methods, either by H2S or CS2 or by the sulfur compounds of the charge. This activation is carried out in situ at a temperature close to the reaction temperature. The raffinate to be treated passes over the catalyst with hydrogen. The hydrogenated product is then separated from the gases and treated with steam to remove H S and the products

  formed during the hydrogenation.

  The method described in the present invention may, in general, apply to the treatment of all

  paraffinic raffinates regardless of the origin of the crude.

  The paraffinic raffinates treated according to the process of the invention advantageously have an aromatic content ranging from 10 to 35% by weight (ASTM D 2007 method). Their viscosity may advantageously be between 3.5 cSt

and 31 cSt at 1000C.

  In the present process, the hydrotreating causes a drop in viscosity of the raffinate all the more important that the diet is heavier. But surprisingly, this gain in fluidity is without significant increase in volatility. The process that is the subject of the present application is advantageously applied to the manufacture of base oils with a high viscosity index, that is to say greater than 95. These base oils are used for the preparation of industrial oils.

  performance: transformer oils, transmission fluids

  heat transfer fluids. These oils require a good

  oxidation resistance and low viscosity at low temperatures

  ture. This method also applies very advantageously to the manufacture of engine oils used in crankcases, gearboxes, bridges, etc ... gasoline engines or

  diesel. The required characteristics are here:

  interesting viscosity tees at high and low temperatures,

  good resistance to oxidation and low volatility.

  It is in this category of lubricants that the

"energy saving oils".

  Finally, the process according to the invention applies to the oils used in oils for an implementation of

  polymerization processes (process oils).

  For all these applications, the bases obtained can be used in the state or in mixture with another hydrogenated base or with a usual base or any base

obtained by the known methods.

  The bases obtained according to the process which is the subject of the present invention have, after dewaxing, viscosities of between 3 and 28 cSt at 100.degree. They allow, by mixing with a more viscous conventional base to reduce the viscosity of the latter without degrading its volatility. Furthermore, it has been found that the oils prepared according to the process described in the present invention have a good response to the conventional additives used in the formulations.

  industrial oils and motor oils.

  The invention is illustrated by the nonlimiting examples below.

Example 1

  A raffinate (No. 1) obtained by furfural treatment of a distillate obtained from a vacuum distillation is hydrogenated.

  an atmospheric residue of Kuwait crude.

  The raffinate characteristics are as follows Raffinat No. 1 Density at 700C 0.8324 Viscosity at 1000C 4.877 cSt% sulfur by weight 0.89 Index of refraction at 68 C 1.4617% aromatics (ASTM method

D 2007) 28.2

  This raffinate is hydrogenated over a hydrogenation catalyst.

  composition composition: MoO3 13.9% by weight NiO 3.1% "

  Support alumina previously sulphurized.

  The hydrogenated product is subjected to a slight vacuum distillation to remove the light products formed during the hydrogenation (topping). The raffinates thus hydrotreated are dewaxed using the methyl isobutyl ketone mixture.

(85%) / methyl ethyl ketone (15%).

  The operating conditions chosen and the results obtained are shown in Table 1 where the yields and qualities of the products obtained according to the process of the present invention are compared with those resulting from

usual process.

  IATROSCAN S-2 thin-layer chromatographic analyzes carried out on the raffinate before and after the hydrogenation show that this hydrogenation affects 81% of the polyaromatic compounds present in the

  raffinate and 28% of monoaromatic compounds.

  TABLE 1 - HYDROGENATION OF REFINING N 1

Pressure bar

R-- -. it-

  H2 / raffinate flown / flown 150 V / V / h. Temperature 1.5 1 1 1

4000C 360 C 3800C 400 C

  Yield% relative to raffinate (weight) after 92.7 97.1 94.6 90.7 heading _ _ _ eag .... Density at 70 C Viscosity at 1000 C cSt% sulfur by weight Refractive index at 68 ° C % aromatics (ASTM D2007 Dewaxing temperature Yield Density at 15 C Refractive index at 20 C Viscosity at 100 C cSt Viscosity at 40 C cSt Pour point VI corrected Volatility Noak (1 h at 250 C)% aromatics (ASTM D2007)

.8183

4.29 0.07

1.4551

  -15 C 83.6 0.863 1.477 4.50 23.53 - 11 28.5 -24 C, 6 0.866 1.478 4.56 24, 10 - 21 102.2 16.9

.8206

4.48 0.06

1.4559

-15 C 0.866

1.4768

4.78, 89 - 11 103.7 -24 C 0.864

1.4778

4.86 26.92 - 22.7

.8203

4.49 0.08

1.4554

-15 C 84.2 0.863

1.4765

4.74, 43-12, 2-24 C, 79.3, 0.865

1.4772

4.79 26.44 - 20 102.3, 3

.8165

4.25 0.06

1.4556

  22.6 -15 C 82.7 0.861 1.477 4.50 23.04 - 12 26.8

-24 C

0.863

1.4778

4,515 23.53 - 24, 5

I i c a ________________i -

  ## EQU1 ## where ## STR1 ## where ## STR1 ## D, | ,, bar pressure TABLE 1 (continued) HYDROGENATION OF REFININ N 1 H2 / raffinate vol / vol 150 V / V / h 0.7 0.5 Temperature 400 C 400 C Rehdement% with respect to raffinate (weight) after 90.3 89 Density at 70 ° C Viscosity at 100 ° C cSt% sulfur by weight Refractive index at 68 ° C aromatic (ASTM D2007) Dewaxing temperature

.8142

4.17

1.4541

22.8 -159C -24C

0.8125

4.12

1.4532

-15oC -240C

REFINED NO

HYDROTREATED

-15 C -24 C

L .... 4 ... 81 7

  Yield 1.83.4 .... 80'81 .... 78 85 82

ii ....... 1 i.

  Density at 15 C Refractive index at 20 C Viscosity at 100 C cSt Viscosity at 40 C cSt Pour point VI corrected Volatility Noak% aromatics (ASTM D2007), 859

1.4762

  22.00 -14 T7 .. 0.860 f, 4765 4.407 22.27 -19 106.3, 4 * M r 0.856

1.4741

4.31 21.35 -12 108.3 0.857

1.4748

4.32 21.55 -21, 8.876

1.4838

, 27 31.46 -11 97.2 -9 -1 7 0.878

1.4846

  , 32 32,27 -18 94,7 11,5 1A t, 'p% 201 0,5 <1 Resistance to oxidation IP 306% deposits 1,52 the 1,03% dt 1,5 ... ## EQU1 ##

specifica-

  The determination of losses by evaporation of oils is carried out according to Noak method DIN 51.581. The values indicated correspond to the weight losses calculated after the oil has been maintained for 1 hour at 2500C. The oxidation resistance is evaluated according to the IP 306 method. The oil is contacted for 48 hours at 120 ° C. with oxygen in the presence of a catalyst (copper). The content of TOP% oxidation products and the

Deposit weight in%.

  We note on this table that a decrease of the space velocity or an increase of the temperature

  hydrotreatment results in a significant increase in

  fluidity and viscosity indices.

  Compared with a base obtained from the same raffinate but with the usual method, it is observed that the process of the present invention leads to more fluid bases having a significantly higher viscosity number.

  and comparable volatility and oxidation resistance.

Example 2

  The process is applied to a raffinate (n0 2) obtained at

  from Kuwait crude and having the following characteristics:

  : Raffinate n0 2 Density at 70C 0.8460 Viscosity at 1000C 9.9 cst Refractive index at 680C 1.4680% aromatics (ASTM D 2007) 12.8 This raffinate is subjected to hydrogenation and

  following treatments identical to those of Example 1.

  The operating conditions of the hydrogenation and the results obtained appear in Table 2 where the yields and the qualities of the products obtained according to the process of the present invention are compared with those of the

usual process.

  Thin layer chromatography analyzes on IATROSCAN S-2 apparatus carried out on the raffinate before then

TABLE 2

HDROGENATION OF THE RAFFINT N 2

HYDROGENATION OF REFINING N 2

  bar: 55 i H2 / raffinate vol / vol: 150 v / v / h: 0.5: temperature: 400 C:% yield with respect to raffinate: (weight) * 86.7 K- 2 4e1 & iN r7fI on I Viscosity at 100 0 cSt Refractive index 68 o% aromatics (ASTM D 2007) * s, oC * U

: 7.07

1.4629

11.5

raffinates

NO

RYDROTRAITI

  dewaxing temperature $ Yield% weight: 73% 80.6%

: 8.6% _

  Density at 15 0 Refractive index at 20oo Viscosity at 100 0 cSt Viscosity at 4000 eSt Pour point VI corrected Volatility Noak% aromatic% (ASTM D 2007)

: 0.871:

14837:

* f

: 7.45:

  49,15: -9:: 6.2: 14.6: * f :: i Resistance to TOP% oxidation IP306% deposits Pressure O m -H Fl oo H eo y H ELI - .. 1 W4 P ri 4t M

-1200:

  q -12oC H H E4cp 0 9 R Ai F4. your * Z> c ', G 0.887

- 1.4885

, 5-111, 17.1

: Speci-

: 0.14 2,4: 0.48 0.7 <1

: <10

: -.

II I [II I I

  Purposes: after hydrogenation show that this hydrogenation affects 75% of the polyaromatic compounds present in the

  raffinate and only 3% of monoaromatics.

Example 3

  A raffinate (n 3) obtained by furfural treatment of a distillate obtained from a vacuum distillation is hydrogenated.

  an atmospheric residue of Zakum crude. Characteristics

  The raffinate is as follows: Raffinate n 3 Density at 70 C 0.8247 Viscosity at 100 C 4.87 cSt Refractive index at 68 C 1.4590% aromatics (ASTM D 2007) 27.5 This raffinate is subject to the following treatments described

  in Example 1: hydrogenation, heading, dewaxing.

  The operating conditions of the hydrogenation, the results obtained as well as the comparison with products obtained by the conventional route are gathered in the

table 3.

TABLE 3

YDROGENATION DURAFFINTN3

HYDROGENATION OF RAFFINAT N 3

  Pressure bar H2 / raffinate vol / vol: 150 Temperature: 400 C: v / v / h: 1.5: I: v / v / hi: 1.5: i Yield% with respect to raffinate (weight) Density at 70 0C Viscosity at 100 0 cSt Refractive index 68 0% aromatics (ASTM D 2007)

raffinates

: 91,2: 89,5: HYDROI'AME

: 0.8159: 0.8138:

: 4.37: 4.28

: 1.4555: 1.4548:

21.5 19.9

  NO -Dewaxing temperature - - 12eUC - u - 'u Yield% weight Density at 15'0 C Index of refraction at 20 C Viscosity at 100 C cSt Viscosity at 400 C cSt Pour point VI corrected% aromatics (ASTM D 2007)

78 76. 77,

: 0.863: 0.86: 0.873

: 1.4775: 1.4770 1.483 (

: 4.65: 4.57: 5.13

: 25.46: 24.29 30.9

: - 10 -: 10

108.4 113.4 103.3

: 27.5: 26.2: 35.5

  ::: e DC) D o i o F4: a -P H ji P, p 2 rA R4qe <W IF! 1 i i j i i b1 - z

Example 4 -

  The process described in Example 1 is applied to a raffinate (n 4) obtained by furfural treatment of a

  vacuum distillation residue of Zakum crude prior

deasphalted with propane.

  The characteristics of the raffinate are as follows: Raffinate n 4 Density at 70 ° C. 0.865 Viscosity at 100 ° C. 26.72 cSt Refractive index at 68 ° C., 4800 As in Example 1, this raffinate is subjected to a

  catalytic hydrogenation, topping, dewaxing.

  The operating conditions of the hydrogenation, the results obtained by analysis of the products and the comparison with products obtained by the conventional way are

collected in Table 4.

TABLFAU 4 -

IYDROGENATION OF THE RAFFINAT

  Pressure II2 / raffina% bar vol / vol i v / vt / Ih 0.5 Temperature 400 C j ...... Yield% with respect to

raf finat j.weight) _ __-

  Density h. 700C Viscosity at 100 C cSt Refractive index 680C Dewaxing temperature 87.2

0.8 to 147

16.75

1.4718

- 120C

raffinates

NO

HYDR0OTPITTES

  - 12oC lZendement 7] weight 74-, 76.6 Density h 150 '] Riractiorn index Viscosity at 100 C Viscosity at -1t0C "Pour point VI corrected

at 20 C

cSt cSt 0.887

1.4945

17,18

174.20

- 12 -

106.6

0.908 ..

1.5002

31.22

-480.66

  - 12 93.1 N 4 o 1q rd o r. H -. O o o p "- 1i Hi Li X4

9 4 CI

p; S4 P 4

ID.1-1

p p C-; Co) Pu. s4 M i X. I f

Claims (11)

  1. Process for producing mineral oils with high   viscosity index, low viscosity, with volatility and resistance   the oxidation-enhanced process comprising vacuum distillation, selective solvent extraction, dewaxing and optionally finishing treatment, characterized in that between the selective solvent extraction step   and the dewaxing step, a hydrogen step is   soft catalytic nation of the raffinate.   2. Process according to Claim 1, characterized in that the catalytic hydrogenation of the raffinate is carried out at a temperature of between 310 and 450 ° C., preferably between 380 and 400 ° C., under a pressure of between 30 and 100 bar. pure hydrogen, preferably equal to or greater than 35 bar, with a space velocity of between 0.25 and 3 and preferably between 1 and 1.5 volume of feed per volume of catalyst and per hour, the ratio of the flow rate of hydrogen under normal conditions of temperature and pressure at 200C hydrocarbon flow rate being included between 100 and 500.   3. Method according to claims 1 and 2, characterized   in that a catalyst containing a Group VI metal and one or more Group VIII metals deposited is used on an alumina support.   4. Process according to Claim 3, characterized in that a catalyst containing oxides of   molybdenum and nickel or molybdenum and cobalt.   5. Process according to Claim 4, characterized in that a catalyst containing approximately 14% by weight   weight of Mo 03 and 3% of Ni O on alumina support.   6. Method according to any one of claims 3   at 5, characterized in that the catalyst is activated by a sulfur compound such as in particular H2S or CS2 or by   the sulfur compounds of the charge.   7. Method according to any one of claims 1   at 6, characterized in that a paraffinic raffinate having a carbon content is used as the charge for the hydrogenation.   in aromatics ranging from 10 to 35% by weight.   8. Process according to any one of claims 1   at 7, characterized in that a paraffinic raffinate having a viscosity of between 3.5 and 31 cSt at 1000C is used as the charge for the hydrogenation. 9. High viscosity grade mineral oils, few   viscous, with improved volatility and oxidation resistance.   obtained by the process according to any one of   Claims 1 to 8, characterized in that   have a viscosity number greater than 95.   10. Mineral oils according to claim 9, characterized   rised by the fact that they have a viscosity included between 3 and 28 cSt at 1000C.   Mineral oils according to claims 8 and 9,   characterized by the fact that they are used as   engine oils called "energy saving oils". i