RU2494140C2 - Lubricating oil composition and method for production thereof - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a lubricant base oil composition containing: (a) mineral oil-derived base oil having content of saturated compounds higher than 90 wt %, sulphur content below 0.03 wt % and viscosity index between 80 and 150, and (b) a paraffin base oil component having viscosity at 100°C from 7 to 30 cSt (from 7 to 30 mm²/s), where component (b) is an isomerised residual product obtained during Fischer-Tropsch synthesis and has percentage ratio of secondary methylene carbon atoms, lying four or more carbon atoms from the terminal group and the branching, to isopropyl carbon atoms, found using a ¹³C-NMR technique, less than 8.2; wherein the base oil mixture has clouding point below 0°C and kinematic viscosity at 100°C higher than 12.0 cSt. The invention also relates to a method of producing a lubricating base oil mixture.

EFFECT: lubricating oil mixture has high viscosity index and high content of saturated compounds with a low pour point.

9 cl, 1 dwg, 5 tbl, 3 ex

Description

FIELD OF THE INVENTION

The invention relates to a lubricant base oil mixture containing (a) a base oil made from mineral oil and having a saturated content of more than 90 wt.%, A sulfur content of less than 0.03 wt.% And a viscosity index (VI) of between 80 and 150, and (b) a Fischer-Tropsch paraffin base oil component and having a kinematic viscosity at 100 ° C. of 7 to 30 cSt (7 to 30 mm ² / s). In addition, the invention relates to a method for producing such mixtures.

State of the art

In a number of applications, there is an increasing demand for high viscosity lubricating base oils. However, the maximum achievable viscosity for any base oils from group II and group III is determined by the origin and composition of the raw materials used - oil distillate or paraffin wax. This is due to the fact that in the process of obtaining oils there is no increase in molecular weight, and therefore the maximum molecular weight and, therefore, the viscosity associated with it cannot be higher than the viscosity of high molecular weight compounds already present in the feed. Moreover, during the stages of hydrotreating or hydrogenation treatment, the molecular weight of the obtained products is constantly reduced due to cracking reactions, and the structure of the compounds is simplified. As a result, Applicants have found that it is extremely difficult to prepare an API Group II base oil from raw materials made from mineral oil with a kinematic viscosity at 100 ° C above 12 cSt, since the harsh conditions of the hydrogenation treatment to achieve the desired content of saturated compounds of at least 90 mass. % means that the maximum viscosity that can be obtained is limited due to the cracking process and the molecular weight of the feed. In addition, it was found that these restrictions are even more pronounced in the case of the base group API oils, where the maximum kinematic viscosity at 100 ° C was not greater than 9 cSt based on raw materials made from mineral oil. However, under less severe conditions of hydrogenation treatment, the obtained base oil does not meet the technical requirements, and also has a reduced oxidation stability and other types of stability are worsened.

A mixture containing a distillate base oil and having a content of saturated compounds of more than 90 wt.% And a component of the residual paraffin base oil produced in the Fischer-Tropsch synthesis is disclosed in US patent A-7053254. Applicants have discovered that although mixtures of mineral base oils with enhanced kinematic viscosity can be obtained by adding the isomerized residual Fischer-Tropsch synthesis products as described in US Pat. No. 7,053,254, the amount of residual Fischer-Tropsch synthesis products that can be added without compromising homogeneity mixture is limited, which is manifested by increasing the cloud point. As a result, the desired kinematic viscosity range at 100 ° C cannot be achieved for mixtures that are transparent and bright at ambient temperature for a long period of time. Alternatively, prior to the mixtures according to the present invention, it was necessary to use rather expensive and difficult to obtain highly viscous poly-alpha-olefin (PAO) fluids in order to achieve a suitable high viscosity, and a large number of expensive and potentially unstable shear viscosity modifiers in order to to obtain lubricating fluids with the desired level of viscosity in combination with a sufficiently high cloud point.

Thus, it is an object of the present invention to provide readily available lubricating base oil compositions that combine a high viscosity index and a high content of saturated compounds with a low pour point, low cloud point, and high kinematic viscosity without using the rigorous hydrotreating / hydrocracking step of the mineral component. An additional objective of the present invention is to develop a method for producing such mixtures.

These goals have been achieved for the following composition. A lubricant base oil mixture that contains (a) a base oil made from mineral oil and having a saturated content of more than 90 wt.%, A sulfur content of less than 0.03 wt.% And a viscosity index between 80 and 150, and (b ) a paraffin base oil component having a viscosity at 100 ° C of 7 to 30 cSt, and component (b) is an isomerized residual product obtained in the Fischer-Tropsch synthesis and having a ratio of the percentage of secondary methylene carbon atoms that are removed by four or more atom carbon from the end group and a branch to the percentage of isopropyl carbon atoms, found by the method of ¹³ C-NMR is less than 8.2. The figure 1 shows the cloud point of a number of mixtures of base oils of group II of mineral origin (a) with 1-10 wt.% Components of the residual paraffin base oil produced in the Fischer-Tropsch synthesis, (b). In addition, pour points are shown. The abscissa shows the mass% of the superheavy base oil (STBM) obtained in the Gas-in-Liquid (HL) process mixed with a Group II base oil with a viscosity of 12 cSt. The ordinate axis shows the temperature (° C). All mixtures were clear and bright by definition, since all cloud temperatures were negative.

As for component (a), lubricating base oils, which are used, for example, to formulate motor lubricants and industrial oils, are usually obtained from suitable mineral oil materials using a variety of refining processes, which are usually aimed at obtaining a lubricating base oil with a given set of characteristics for example, viscosity, resistance to oxidation and retention of fluidity over a wide temperature range (which is characterized by a viscosity index). The traditional preparation of a lubricating base oil is as follows. Mineral oil is separated by atmospheric distillation into a number of distillate fractions and a residue, which is called a broad residual fraction. The broad residual fraction is then separated by distillation under reduced pressure into a series of vacuum distillates and a vacuum residue known as vacuum distillation fuel oil. Lubricating base oils are obtained from vacuum distillate fractions using refining processes. Using these processes, aromatic hydrocarbons and wax are removed or chemically converted into acceptable molecular components of the distillate base oil from the vacuum distillate fractions. Asphalt from vacuum distillation fuel oil can be removed using known deasphalting processes. Aromatic hydrocarbons and wax thus obtained by deasphalting the oil can be subsequently removed in order to obtain a residual lubricating base oil, known as high viscosity cylinder oil. The wax obtained by cleaning various fractions of a lubricating base oil is called a “paraffin wax”. Lubricating base oils are usually prepared from the appropriate vacuum distillate fractions and / or deasphalted oil using suitable refining processes, including quality improvement processes using catalysts and solvents, and dewaxing and catalytic hydrotreating processes.

Lubricating base oils derived from mineral crude oil are also called API group I, II or III base oils, which are defined in API publication 1509: System for certification and licensing of motor oils, “E-API Appendix. Substitution rules for base oils for passenger motor oils and diesel vehicles. ”The Oil & Gas Journal, Sept. 1, 1997, pp. 63-70, describes various processes for preparing API Group II base oils. All possible routes may include at least one step of solvent extraction or hydrogenation aromatic and other n unsaturated compounds in order to obtain a base oil having the desired content of saturated compounds, usually such a hydrogenation step can be carried out by contacting the feed with hydrogen in the presence of a hydrogenation catalyst, typically a supported Group VIII metal, an example of which is described in US Pat. No. 5,935,416.

Although it is thus possible to obtain API group II base oils, API group III base oils, that is, oils having a viscosity index of at least 120, are more difficult to obtain directly by such processes. Instead, it is advisable to obtain such oils by hydrotreating a paraffin wax obtained during processing, for example, as described in patent EP-A-178710. Alternatively, API Group III lubricating base oils can be obtained directly from high wax feeds derived from crude paraffin oils using a process that involves contacting a hydrocarbon feed obtained from crude paraffin oil with a hydroisomerization catalyst under hydroisomerization conditions with subsequent isolation of a lubricating base oil having a high viscosity index. Such a process is described, for example, in document EP-A-0400742. In both cases, the maximum achievable kinematic viscosity of such base oils is determined by the maximum number of carbon atoms, which is expressed as the number average molecular weight and molecular weight distribution of the feed. In the base oil mixtures according to the invention, component (a) of the base oil of mineral origin is preferably present in an amount of from 40 wt.% To 98 wt.%, Based on the total weight of the oil mixture, more preferably from 50 to 97 wt.%, More preferably from 60 to 96 wt.%, More preferably from 70 to 95 wt.%, More preferably from 80 to 94 wt.%, And more preferably from 90 to 93 wt.%. The residue is component (b) of a paraffinic base oil. Preferably, component (a) of the base oil mixture has a kinematic viscosity at 100 ° C. of greater than 12.0 cSt, more preferably greater than 15.0 cSt, even more preferably greater than 20.0 cSt, and a viscosity index greater than 95, more preferably greater than 100. Preferably, the viscosity index of component (a) is between 100 and 110, however, it can be reduced due to the high contribution of the VI of component (b). The base oil mixture according to the invention preferably has a cloud point below 0 ° C.

Preferably, in a base oil mixture according to the invention, component (a) is an API group II and / or group III base oil as defined in API publication 1509.

The Fischer-Tropsch derived paraffin component (b) of the heavy base oil according to the invention is a heavy hydrocarbon composition containing at least 95% by weight of paraffin molecules. Preferably, the heavy component (b) of the base oil according to the invention is obtained from a Fischer-Tropsch synthesis wax, and it contains more than 98 wt.% Saturated, paraffin hydrocarbons. Preferably, at least 85 wt.%, More preferably at least 90 wt.%, Even more preferably at least 95 wt.%, And most preferably at least 98 wt.% Of these molecules paraffin hydrocarbons are isoparaffins. Preferably, at least 85% by weight of saturated paraffinic hydrocarbons are non-cyclic hydrocarbons. Naphthenic compounds (paraffinic cyclic hydrocarbons) are preferably present in an amount of not more than 15 wt.%, More preferably less than 10 wt.%.

The Fischer-Tropsch derived paraffin component (b) of the base oil contains hydrocarbon molecules having consecutive numbers of carbon atoms; thus, the component contains an almost continuous consecutive series of isoparaffins, i.e., isoparaffins having n, n + 1, n + 2, n + 3 and n + 4 carbon atoms. These consecutive numbers of carbon atoms represent the sequence of hydrocarbon products of the Fischer-Tropsch synthesis, from which receive raw wax, which is subjected to isomerization with the formation of component (b).

In addition, component (b) is a liquid at 100 ° C and ambient conditions, that is, at 25 ° C and one atmosphere (101 kPa) of absolute pressure.

Typically, the composition of the heavy hydrocarbons is a liquid under conditions of temperature and pressure during operation and is typical, but not always, at an ambient temperature of 24 ° C and a pressure of one atmosphere (101 kPa).

The kinematic viscosity at 100 ° C (KB 100) of component (b), which is measured according to ASTM D-445, is at least 7 cSt (7 mm ² / s). Preferably, the kinematic viscosity of the heavy hydrocarbon compositions of the invention at 100 ° C. (KB 100) is at least 10 cSt, more preferably at least 13 cSt, even more preferably at least 15 cSt, and even more preferably at least at least 17 cSt, even more preferably at least 20 cSt, and most preferably at least 25 cSt. The kinematic viscosity described in the present invention is determined according to ASTM D-445.

The boiling point distribution of samples boiling over 535 ° C is measured according to ASTM D-6352, while for low-boiling materials, the boiling point distribution is measured according to ASTM D-2887.

The initial and final boiling points given here are nominal and refer to cut-off points of 5% and 95% of the product (boiling point) obtained using the gas chromatographic imitation distillation (GCD) method described above.

Preferably, component (b) has a boiling point of at least 400 ° C. More preferably, the boiling point is at least 450 ° C, even more preferably at least 480 ° C, more preferably more than 500 ° C, even more preferably more than 540 ° C.

Since hydrocarbons traditionally derived from oil and hydrocarbons obtained in the Fischer-Tropsch synthesis contain a mixture of hydrocarbons with different molecular weights having a wide boiling range, boiling points of 10 wt.% And 90 wt.% In the corresponding ranges will be used in the present invention boiling. The boiling point of 10 wt.% Means the temperature at which 10 wt.% Of the hydrocarbons present in this fraction will evaporate at atmospheric pressure and, thus, can be released. Similarly, a boiling point of 90 wt.% Means the temperature at which 90 wt.% Of the hydrocarbons present will evaporate at atmospheric pressure. When referring to the distribution of the boiling range, the present invention refers to the boiling range between the sampling points of 10 wt.% And 90 wt.%.

Component (b) according to the invention preferably contains molecules having a sequential number of carbon atoms, and preferably at least 95% by weight of C ₃₀₊ hydrocarbon molecules. More preferably, component (b) contains at least 75 wt.% C ₃₅₊ hydrocarbon molecules.

The term "cloud point" refers to the temperature at which a cloud point develops in a sample, which is determined by ASTM D-5773. Component (b) typically has a cloud point between -60 ° C and + 49 ° C.

In the base oil mixture according to the invention, preferably component (b) has a pour point below -28 ° C. Moreover, in the base oil mixture according to the invention, preferably component (b) does not have a measurable effect of reducing the pour point, so that the pour point of the base oil mixture is intermediate between and not lower than that for components (a) and (b), than for any of the components (a) and (b). Preferably component (b) has a cloud point between 30 ° C and -55 ° C, more preferably between 10 ° C and -50 ° C. It was found that, depending on the feedstock and the dewaxing conditions, some of the heavy components (b) of the base oil produced in the Fischer-Tropsch synthesis may have a cloud point above ambient temperature, although other characteristics do not adversely affect.

The term “pour point” refers to the temperature at which the flow of a base oil sample will begin under carefully controlled conditions. The pour point referred to in the present invention is determined according to ASTM D 97-93. Molecular weight is determined according to ASTM D-2503. Viscosity Index (VI) is determined using ASTM D-2270. According to the invention, component (b) preferably has a viscosity index between 120 and 170, more preferably from 135 to 165, even more preferably from 150 to 160.

Preferably component (b) does not or will contain very few compounds containing sulfur and nitrogen. This is typical of a product made in the Fischer-Tropsch synthesis, which uses synthesis gas with almost no impurities. Preferably component (b) contains sulfur, nitrogen and metals in the form of compounds with hydrocarbons and is present in an amount of less than 50 weight. ppm, more preferably less than 20 weight. ppm, even more preferably less than 10 weight. ppm Most preferably, this component will have a sulfur and nitrogen content typically below their detection limits, which are currently 5 ppm for sulfur and 1 ppm for nitrogen, when X-ray or Antek Nitrogen assays are used for determination. However, sulfur may enter the product through the use of sulfidized hydrocracking / hydrodewaxing catalysts and / or sulfidized dewaxing catalysts.

In addition, it was found that, apparently, there is a correlation between the kinematic viscosity, the pour point and the effect of lowering the pour point, which may have an isomerized residual product obtained in the Fischer-Tropsch synthesis. For a given raw material composition and boiling range (which is determined by the lower cut-off point from the distillate base oil and gas oil fractions after dewaxing) for the bottoms product, the pour point and the resulting viscosity are associated with the rigidity of the dewaxing treatment. It was found that the effect of reducing the pour point was significant for the isomerized residual product obtained in the Fischer-Tropsch synthesis having a pour point above -28 ° C, an average molecular weight of between about 600 and 1100, and an average degree of branching of the molecules between about 6, 5 and 10 alkyl branches per 100 carbon atoms, as described in US patent A-7053254. In the present invention, the paraffin component (b) of the Fischer-Tropsch derived base oil is preferably isolated as a residual fraction from hydrocarbons obtained during the Fischer-Tropsch synthesis and subsequent hydrocracking and dewaxing steps.

More preferably, this fraction is a distillation residue containing the highest molecular weight compounds that are still present in the product of the hydroisomerization step. A sampling point of 10% by weight of said boiling fraction is preferably greater than 370 ° C., more preferably it is higher than 400 ° C. and most preferably higher than 500 ° C. for certain embodiments of the present invention.

In addition, this fraction has an average degree of branching of the molecules above 10 alkyl branches per 100 carbon atoms, as described in accordance with the method disclosed in US patent A-7053254.

The paraffin component (b) of the base oil produced in the Fischer-Tropsch synthesis according to the invention can be further characterized by the content of various carbon fragments. More specifically, the Fischer-Tropsch derived paraffin component (b) of the base oil can be characterized by the percentage of epsilon-methylene carbon atoms, i.e., the percentage of secondary methylene carbon atoms that are four or more carbon atoms away from the terminal group, and branch (additionally referred to as CH ₂ > 4) compared to the percentage of isopropyl carbon atoms.

It was found that the isomerized bottoms product of the Fischer-Tropsch synthesis, which is disclosed in US patent A-7053254, differs from the paraffin components of the base oil produced in the Fischer-Tropsch synthesis according to the present invention, which are usually obtained with high dewaxing stiffness, in that that the latter compounds have a ratio of the percentage of epsilon-methylene carbon atoms to carbon atoms in isopropyl branches of 8.2 or higher, which is measured for the entire Fischer-Tropsch base oil. In particular, it was found that the product of the Fischer-Tropsch synthesis, which is disclosed in US patent A-7053254, with a moderate degree of isomerization is not suitable for adding in an amount of more than 1.5-2 wt.% Due to the impossibility of obtaining a clear and bright mixture .

It was found that the measurable effect of reducing the pour point due to mixing with the base component, which is disclosed in US Pat. No. 7,053,254, is achieved only if in component (b) the ratio of the percentage of epsilon-methylene carbon atoms to carbon atoms in isopropyl branching is equal to 8.2 or more. Therefore, the Fischer-Tropsch derived base oil component (b) of the present invention has a pour point below -28 ° C. Such component (b) will have only a slight effect of reducing the pour point or will not have an effect, thus, the pour point of base oil mixtures containing components (a) and (b) will be intermediate between the pour point of these components.

The characteristics of the branching, as well as the carbon composition of the components of the mixing of the base oil produced in the Fischer-Tropsch synthesis, can be conveniently determined by analyzing the oil sample using ¹³ C-NMR, vapor pressure osmometry (NDP) and mass spectrometric analysis with field ionization ( MSRP) as follows.

The average molecular weight is determined using vapor pressure osmometry (NDP). The samples are then characterized at the molecular level using nuclear magnetic resonance spectroscopy (NMR). The content of "Z" and the average number of carbon atoms are determined by the MSRP method.

In conventional NMR spectroscopy, there is a problem of signal overlapping due to the presence of a large number of isomers in the base oil. To overcome the problem of signal overlapping, nuclear magnetic resonance analyzes with a selected carbon-13 isotope with reduced multiplicity ( ¹³ C-NMR) are used. In particular, the method of synchronized spin echo (SISPE) is used to obtain a quantitative CH _n subspectrum. Quantitative data obtained by the SISPE method have higher accuracy than the data obtained by the undistorted amplification method under the influence of the polarization transition (NIUPP, which was used, for example, in the method disclosed in US patent A-7053254).

Based on the SISPE data and the average molecular weight obtained by the vapor pressure osmometry (VDP) method, the average number of branches and aliphatic rings can be calculated. In addition, based on the SISPE data, it is possible to obtain a distribution of the length of side chains and the positions of the methyl groups along the straight chain.

Quantitative analysis of the multiplicity of carbon atoms is usually carried out completely at room temperature. However, this applies only to materials that are liquid under such conditions. This method is applied to any materials of synthetic base oils (for example, from Fischer-Tropsch synthesis) or mineral origin, which are turbid or waxy solids at room temperature, and therefore cannot be carried out in the usual way. The NMR measurement methodology was as follows: deuterated chloroform (CDCl ₃ ) was used as a solvent for quantitative analysis of the multiplicity of carbon atoms, limiting the maximum measurement temperature to 50 ° C for practical reasons. The base oil sample is heated in a thermostat to 50 ° C until it becomes a transparent and liquid homogeneous product. Then part of the sample is transferred to NMR. Preferably, the temperature of the NMR ampoule and any device used in transferring the sample is maintained at this level. Then, the above solvent is added, and the ampoule is shaken to dissolve the sample, with the optional use of reheating the sample. In order to prevent the solidification of any materials with a high melting point in the sample, the temperature of the NMR instrument is maintained at 50 ° C during data acquisition. The sample is placed in the NMR instrument for at least 5 minutes, which is required to achieve temperature equilibrium. After that, the device must be readjusted and reconfigured, since both of these measurements can significantly change at elevated temperatures, and now it is possible to record NMR data.

The CH ₃ subspectrum can be obtained using the SISPE pulse sequence obtained by adding the SSE spectrum (standard spin echo) to 1 / J SISPE (synchronized spin echo). The resulting spectrum contains only the peaks of the primary (CH ₃ ) and tertiary carbon atom (CH). The resonance of the various carbon branches at specific positions and their length are then determined using tabular data and adjustments at the end of the chain. Then integrate the subspectrum in order to obtain quantitative values for various signals of CH ₃ as follows.

1) CH ₃ - carbon

but. The chemical shift is 25 ppm. (using the standard - TMS).

b. Shifts 19 and 21 ppm can be identified as metal branches of the following general type (see formula I):

from. Clear intense signals in the 22-24 ppm area can be unambiguously identified as isopropyl end groups of the following general structure (see formula 2).

In this case, one of the methyl carbon atoms is classified as the end of the main chain, and the other is a branch. Therefore, when calculating the content of methyl branches, half the intensity of these signals is taken into account.

d. In addition, it is believed that several weak signals in the region from 15 to 19 ppm. belong to the isopropyl group with additional branching at position-3.

e. It is most likely that some weak signals observed in the spectrum in the region from 8 to 8.5 ppm refer to 3,3-dimethyl substituted structures (formula 3):

In this case, the observed signal belongs to the end group of CH ₃ , however, there are two corresponding methyl branches. Therefore, the integral value of these signals is doubled (signals for two metal branches are not calculated independently).

Thus, the total estimate of the content of methyl branches is based on the following calculation (the abbreviation "Int" means "integral", formula 4):

Σ (methyl integrals) = Int (from 19 to 20 ppm + ½Int (from 22 to 25 ppm) + Int (from 15 to 19 ppm) + 2 · Int (from 7.0 to 9 ppm)

2) Calculation of the content of ethyl branching is based on two distinct relatively intense signals that are observed at 11.5 and 10.9 ppm, assuming that the content of isopentyl end groups is low, based on the assessment data for other peaks. Therefore, the calculation of the content of ethyl branches is based only on the integral of signals from 10 to 11.2 ppm.

3) The total theoretical content of the end groups of CH _{3 is} calculated based on the content of "Z" and the average number of carbon atoms, which is determined by the method of MSRP. Then, the content of C ₃₊ branches is determined by subtracting from the theoretical content of terminal CH ₃ groups the known content of terminal CH ₃ groups, i.e., half the value for isopropyl groups, 3-methyl substituted groups and for 3,3-dimethyl substituted structures, thus obtaining for signals in the region of 14 ppm, which refers to the CH ₃ groups ending the chain, and the difference gives a value for C ₃₊ branches:

Σ (C ₃ + branching integrals) = Int (from 14 to 15 ppm) - ((theoretical content of terminal CH ₃ ) -Int (from 11.2 to 11.8 ppm) - ½Int (from 22 up to 25 ppm) - Int (from 7 to 9 ppm)).

In addition, the present invention relates to a method for producing a lubricating base oil mixture, which comprises mixing:

(a) a base oil made from mineral oil having a saturated content of more than 90 wt.%, a sulfur content of less than 0.03 wt.% and a viscosity index between 80 and 150, and

(b) a paraffin base oil component having a viscosity at 100 ° C of 7 to 30 cSt (7 to 30 mm ² / s), where component (b) is a Fischer-Tropsch derived isomerized residual product and having a percentage the proportion of secondary methylene carbon atoms that are four or more carbon atoms away from the end group and the branch to the percentage of isopropyl carbon atoms found using the 13C-NMR method is less than 8.2.

Preferably, the present invention also relates to a method for producing a lubricating base oil having a saturated content of more than 90 wt.%, A sulfur content of less than 0.03 wt.%, A viscosity index between 80 and 150, which includes: (a) contacting the feed, produced from mineral oil, as described above, with hydrogen in the presence of a hydrogenation catalyst, and (b) mixing the resulting product with component (b) produced in the Fischer-Tropsch synthesis in accordance with any one of paragraphs 1-7.

More preferably, the above method comprises the steps of:

(i) contacting a mineral precursor of a product, a lubricating base oil, having a saturated content of less than 90 wt.% and a sulfur content of between 300 wt. ppm and 2 wt.%, with a suitable sulfidized hydrotreating catalyst in the presence of hydrogen in the first hydrotreating stage at a temperature between 250 and 350 ° C; and

(ii) separating the stream leaving after step (i) into a gaseous fraction and a liquid fraction, where the liquid fraction has a sulfur content between 50 and 1000 weight. ppm and a nitrogen content of less than 50 weight. ppm

(iii) contacting the liquid fraction from step (ii) with a catalyst containing a noble metal component supported on an amorphous refractory oxide support in the presence of hydrogen in a second hydrotreatment step;

(iv) isolating a lubricating base oil having specific properties, and

(v) mixing the base oil obtained in step (iv) with the paraffin component (b) of the base oil.

Preferably, the hydrotreating catalyst in step (i) comprises at least one metal component from the VIB groups and a metal selected from the group consisting of iron, nickel and cobalt and a refractory oxide support. Even more preferably, the catalyst of step (i) is a nickel / molybdenum alumina catalyst having a nickel content of 1-5 wt.% As an oxide and a molybdenum content between 10 and 30 wt.% As an oxide. And in this case, more preferably, the catalyst of stage (w) contains platinum and palladium and an amorphous aluminosilicate carrier, in which the total amount of platinum and palladium is between 0.2 and 5 wt.%.

Preferably, the lubricating base oil product is obtained by solvent extraction of an oil fraction boiling in the lubricating oil range, followed by dewaxing with a solvent and / or catalytic dewaxing. Preferably, the lubricating base oil product is an API group I base oil, and the product obtained in step (d) is an API group II or group III base oil. Preferably, the paraffin component (b) of the base oil is a heavy residual fraction after distillation of the wax produced in the Fischer-Tropsch synthesis, or paraffin raffinate feedstock obtained by:

(a) hydrocracking / hydroisomerization of a Fischer-Tropsch derived feedstock in which at least 20% by weight of the compounds in the Fischer-Tropsch feedstock has at least 30 carbon atoms;

(b) separating the product of step (a) into one or more distillate fractions and a residual heavy fraction containing at least 10 wt.% compounds boiling above 540 ° C;

(c) the residual fraction is subjected to catalytic treatment at the stage of lowering the temperature of the yield stress; and

(d) recovering from the stream leaving after step (c) as a residual heavy fraction of the paraffin component of the base oil produced in the Fischer-Tropsch synthesis.

More preferably, the paraffin component (b) of the base oil is a heavy residual fraction after distillation of the Fischer-Tropsch wax or paraffin raffinate feed obtained by:

a) hydrocracking / hydroisomerization of raw materials produced in the Fischer-Tropsch synthesis, in which, the weight ratio of compounds having at least 60 or more carbon atoms, and compounds having at least 30 carbon atoms in the raw material produced in Fischer-Tropsch synthesis is at least 0.2 and in which at least 30 wt.% of the compounds in the feed produced in the Fischer-Tropsch synthesis has at least 30 carbon atoms;

(b) separating the product of step (a) into one or more distillate fractions of low boiling fractions, a broad base oil precursor fraction, and a heavy fraction, such that the boiling point of 90 wt.% of the base oil precursor fraction is between 350 and 550 ° C;

(c) treating the broad base oil precursor fraction obtained in step (b) in the step of lowering the pour point; and

(d) a heavy residual fraction is isolated by distillation of the product of step (c).

In addition to isomerization and fractionation, fractions of the product produced in the Fischer-Tropsch synthesis can be subjected to various other treatments, such as hydrocracking, hydrotreating and final hydrotreating.

The feedstock in step (a) is a product made in a Fischer-Tropsch synthesis. The boiling point of the Fischer-Tropsch synthesis product may be up to 400 ° C, but preferably it is below 200 ° C. Preferably, any compounds having 4 or less carbon atoms and any compounds having a boiling point in this range are isolated from the Fischer-Tropsch synthesis product before using the synthesis product at the indicated hydroisomerization step. An example of a suitable Fischer-Tropsch synthesis is described in WO-A-9934917 and AU-A-698391. In these processes, the product of the Fischer-Tropsch synthesis, which is described above, is obtained.

The Fischer-Tropsch synthesis product will contain few or no sulfur and nitrogen compounds. This is characteristic of a product made in the Fischer-Tropsch synthesis, in which synthesis gas is used, almost free of impurities. Typically, the sulfur and nitrogen contents are less than the detection limits, which are currently 5 ppm for sulfur and 1 ppm for nitrogen. The Fischer-Tropsch synthesis product can be obtained using well-known processes, for example, the so-called Sasol process, Shell distillate production process, or ExxonMobil AGC-21 process. These and other processes, for example, are described in more detail in documents EP-A-776959, EP-A-668342, US-A-4943672, US-A-5059299, WO-A-9934917 and WO-A-9920720. Typically, the process will include Fischer-Tropsch synthesis and the hydroisomerization step, which is described in these publications. Fischer-Tropsch synthesis can be carried out using synthesis gas derived from any kind of hydrocarbon material, such as coal, natural gas, biological material, such as wood or hay.

The Fischer-Tropsch synthesis product obtained directly from the Fischer-Tropsch synthesis contains a paraffin fraction, which is usually solid at room temperature.

The wax used as raw material in the method according to the invention is obtained using the well-known method for producing hydrocarbons - Fischer-Tropsch synthesis. In general, such a Fischer-Tropsch hydrocarbon synthesis involves the production of hydrocarbons from a mixture of carbon monoxide and hydrogen at elevated temperature and pressure in the presence of an appropriate catalyst. Typically, the Fischer-Tropsch synthesis catalyst has selectivity in the preparation of paraffin molecules, mainly straight chain paraffins, and therefore the Fischer-Tropsch synthesis product is usually a mixture of a large number of paraffin molecules. Those hydrocarbons that are gaseous or liquid at room temperature are isolated separately, for example, in the form of fuel gas (C _5- ), raw materials for solvents and raw materials for detergents (up to C ₁₇ ). Heavier paraffins (C ₁₈₊ ) are isolated in the form of one or more fractions of wax, which are usually called wax (s) or synthetic wax (s). In the framework of the present invention, only those Fischer-Tropsch waxes are used as raw materials that meet the above requirements with respect to their boiling range and pour point. Preferred raw materials are those Fischer-Tropsch synthesis waxes that have a pour point in the range of 55 to 150 ° C, more preferably 60 to 120 ° C and / or a boiling range such that the difference between the sampling points is 90 and 10% (T90- T10) is in the range from 50 to 130 ° C. Fischer-Tropsch synthesis waxes melting below 100 ° C. typically have a kinematic viscosity at 100 ° C. (KB 100) of at least 3 cSt (3 mm ² / s), preferably between 3 and 12 cSt, more preferably between 4 and 10 cSt. Those Fischer-Tropsch synthesis waxes that melt above 100 ° C typically have a kinematic viscosity at a temperature T that is 10-20 ° C higher than their melting point, in the range of 8 to 15 cSt, preferably 9 to 14 cSt .

In the case where the feed for step (a) has a boiling point of 10 wt.% Above 500 ° C., the wax content will usually be greater than 50 wt.%. Preferably, the feed for the hydroisomerization step is a Fischer-Tropsch synthesis product in which there is at least 30 wt.%, Preferably at least 50 wt.%, And more preferably at least 55 wt.% Of the compounds, having at least 30 carbon atoms. In addition, the weight ratio of compounds having from more than 30 to at least 60 or more carbon atoms to compounds having at least 30 carbon atoms to less than 60 carbon atoms in the Fischer-Tropsch synthesis product is at least 0.2, preferably at least 0.4, and more preferably at least 0.55.

Preferably, the Fischer-Tropsch synthesis product contains a C ₂₀₊ fraction having an alpha coefficient (Anderson-Schulph-Flory distribution growth factor) of at least 0.925, preferably at least 0.935, more preferably at least 0.945, still more preferably at least 0.955. Preferably, the Fischer-Tropsch raw wax for step (a) has a weight ratio of compounds having at least 60 or more carbon atoms and compounds having at least 30 carbon atoms in the Fischer-Tropsch feed is at least 0.2, more preferably at least 0.4.

Preferably, the hydrocracking / hydroisomerization process during hydroisomerization is carried out in the presence of hydrogen and a catalyst, the catalyst may be selected from those known to those skilled in the art as suitable for this process. The catalysts used in the hydroisomerization process typically contain acid functionality and hydrogenation-dehydrogenation functionality. Preferably, the acid functionality is carried by refractory metal oxide carriers. Suitable carrier materials include silica, aluminosilicate, alumina, zirconia, titanium dioxide, and mixtures thereof. Preferred carrier materials for incorporation into the catalyst used in the process of the present invention are silica, alumina and aluminosilicate. A particularly preferred catalyst comprises platinum supported on an aluminosilicate carrier. Preferably, the catalyst does not contain halogen compounds, such as, for example, fluorine, since the use of such catalysts requires special operating conditions and environmental problems. Examples of suitable hydrocracking / hydroisomerization processes and corresponding catalysts are described in documents WO-A-0014179, EP-A-532118, EP-A-666894 and earlier refer to EP-A-776959.

Preferably, the hydrogenation-dehydrogenation functionality is carried by Group VIII metals, for example, cobalt, nickel, palladium and platinum, and more preferably platinum. In the case of platinum and palladium, the catalyst may contain an active hydrogenation-dehydrogenation component in an amount of from 0.005 to 5 parts by weight, preferably from 0.02 to 2 parts by weight, per 100 parts by weight of carrier material. In the case of nickel, an increased metal content may be present, moreover, nickel is optionally used in combination with copper. A particularly preferred catalyst for use in the hydroconversion step comprises platinum in an amount in the range of 0.05 to 2 parts by weight, more preferably 0.1 to 1 part by weight, per 100 parts by weight of carrier material. In addition, the catalyst may contain a binder material to enhance the strength of the catalyst. Binder material may be non-acidic. Examples are clays and other binders that are known to those skilled in the art. In the process of hydroisomerization, the feed is contacted with hydrogen in the presence of a catalyst at elevated temperature and pressure. The temperature is usually in the range from 175 to 380 ° C, preferably higher than 250 ° C and more preferably from 300 to 370 ° C. Typically, the pressure is in the range of 10 to 250 bar, and preferably between 20 and 80 bar. Hydrogen gas can be supplied at a space velocity from 100 to 10,000 norms. l / (l · h), preferably from 500 to 5000 standards. l / (l · h). The hydrocarbon feed may be supplied at a weight rate per catalyst volume of from 0.1 to 5 kg / (l · h), preferably higher than 0.5 kg / (l · h) and more preferably less than 2 kg / (l · h ) The ratio of hydrogen to hydrocarbon feedstock can vary from 100 to 5000 standards. l / kg and preferably from 250 to 2500 norms. l / kg

The degree of conversion during the hydroisomerization process, which is defined as the weight percent of raw materials boiling above 370 ° C, which is converted in one pass into a fraction boiling below 370 ° C, is at least 20 wt.%, Preferably at least 25 wt.%, but preferably not more than 80 wt.%, more preferably not more than 70 wt.%. The term feed used in the definition above is the sum of the hydrocarbon feed supplied to the hydroisomerization process, thus also including any optional recycling to step (a).

The product obtained during the hydroisomerization process preferably contains at least 50 wt.% Isoparaffins, more preferably at least 60 wt.%, Even more preferably at least 70 wt.% Isoparaffins, and the rest is n- paraffinic and naphthenic compounds.

In step (b), the product of step (a) is separated into one or more distillate fractions and a heavy residual fraction containing at least 10 wt.% Compounds boiling above 540 ° C.

This is conveniently accomplished using one or more distillation separations of the stream leaving the hydroisomerization step in order to obtain at least one fuel fraction of a middle distillate and a residual fraction that can be used in step (c).

Preferably, the stream leaving step (a) is first subjected to atmospheric distillation. The resulting distillation stream, in some preferred embodiments, may be subjected to further distillation, carried out under minimal vacuum, to obtain a fraction having an increased sampling point of 10% by weight of the product.

The sampling point of 10 wt.% Of the residue may preferably vary between 350 and 550 ° C. In this residual product of atmospheric distillation or a residue, preferably at least 95 wt.% Boil above 370 ° C. This fraction can be used directly in step (c) or can be subjected to additional vacuum distillation, which is carried out under a pressure between 0.001 and 0.1 bar (abs.). The feed for step (c) is preferably obtained as the bottom product of such a vacuum distillation. In step (c), the heavy residual fraction obtained in step (b) is subjected to catalytic treatment in the step of reducing the pour point. Stage (C) can be carried out using any hydroconversion process, which is able to reduce the wax content below 50 wt.% From the initial wax content. Preferably, the wax content of the intermediate is below 35 wt.% And more preferably between 5 and 35 wt.%, And even more preferably between 10 and 35 wt.%. Preferably, the product obtained in step (c) has a pour point below 80 ° C. Preferably, more than 50 wt.% And more preferably more than 70 wt.% Of the intermediate product is boiled above the sampling point of 10 wt.% Of the paraffin feed used in step (a). The term wax content used in the description is measured in accordance with the following procedure. The determined oil fraction (1 part by weight) is diluted with 4 parts of a mixture (50/50 by volume) of methyl ethyl ketone and toluene, which is successively cooled to -20 ° C in the refrigerator. Then the mixture is filtered at -20 ° C. The wax is thoroughly washed with a cold solvent, removed from the filter, dried and weighed. If reference is made to the oil content, then the value (in wt.%) Means 100% minus the wax content in wt.%.

A possible method is the hydroisomerization process described above for step (a). It has been found that the wax content can be reduced to the desired level using such a catalyst. By varying the stringency conditions of the process as described above, one skilled in the art can easily determine the necessary operating conditions in order to achieve the desired degree of wax conversion. However, to optimize the oil yield, a temperature between 300 and 330 ° C. and a weight feed rate between 0.1 and 5, more preferably between 0.1 and 3 kg of oil per liter of catalyst per hour (kg / (l · h)) are particularly preferred. .

A more preferred class of catalysts that can be used in step (c) is the class of dewaxing catalysts. When using such catalysts, the process conditions used should be such as to preserve the wax content of the oil. Unlike typical catalytic dewaxing processes, where the goal is to reduce the wax content to almost zero. By using a dewaxing catalyst containing a molecular sieve, it is possible to achieve a result that the heavier molecules remain in the dewaxed oil. Thus, a more viscous base oil can be obtained.

The dewaxing catalyst, which can be used in step (c), advantageously contains a molecular sieve, optionally in combination with a metal that performs the function of hydrogenation, such as a Group VIII metal. Molecular sieves, and more suitably molecular sieves having a pore diameter of between 0.35 and 0.8 nm, have shown good catalytic activity while reducing the wax content of paraffin feed. Suitable zeolites are mordenite, beta, ZSM-5, ZSM-12, ZSM-22, ZSM-23, SSZ-32, ZSM-35 and ZSM-48, or a combination of these zeolites, of which ZSM-12 and ZSM class zeolites are most preferred. -48. Another preferred group of molecular sieves are silicoaluminophosphate (SAPO) materials, of which SAPO-11 is most preferred, for example, as described in US Pat. No. 4,859,311. Zeolite ZSM-5 can optionally be used in the form of HZSM-5, in the absence of any Group VIII metal. Other molecular sieves are preferably used in combination with added Group VIII metal. Suitable Group VIII metals are nickel, cobalt, platinum and palladium. Examples of possible combinations are Pt / ZSM-35, Ni / ZSM-5, Pt / ZSM-23, Pd / ZSM-23, Pt / ZSM-48 and Pt / SAPO-11 or layered Pt / zeolite beta and Pt / ZSM -23, Pt / zeolite beta and Pt / ZSM-48 or Pt / zeolite beta and Pt / ZSM-22. Additional details and examples of suitable molecular sieves and conditions for dewaxing are described, for example, in documents WO-A-9718278, US-A-4343692, US-A-5053373, US-A-5252527, US-A-20040065581, US-A- 4574043 and EP-A-1029029. Another preferred class of molecular sieves are those that have a relatively low selectivity for isomerization and a high selectivity for wax conversion, such as zeolite ZSM-5 and ferrierite (ZSM-35).

It is advisable that the dewaxing catalyst also contains a binder material. This binder can be a substance of synthetic or natural origin (inorganic), for example, clay, silicon dioxide and / or metal oxides. For example, clays of natural origin are clays of the montmorillonite and kaolin family. Preferably, the binder material is a porous binder, for example, refractory oxides, examples of which are alumina, aluminosilicate, silica-magnesium oxide, silica-zirconia, silica-thorium dioxide, silica-beryllium dioxide, silica-dioxide titanium, as well as ternary compositions, for example, silica-alumina-thorium dioxide, silica-alumina-zirconia, silica-alumina-magnesium oxide and silica-magnesium oxide-cir horse. More preferably, a low acidity binder oxide refractory material that is substantially free of alumina is used. Examples of such binders are silicon dioxide, zirconia, titanium dioxide, germanium dioxide, boron oxide and mixtures of two or more of these materials, examples of which are given above. The most preferred binder is silica.

A preferred class of dewaxing catalysts comprises intermediate zeolite crystallites as described above, and a low acidity binder oxide refractory material substantially free of alumina as described above, wherein the surface of the aluminosilicate zeolite crystallites is modified by dealuminating treatment of the zeolite surface. Preferably dealumination treatment consists in contacting the extrudate of the binder and zeolite with an aqueous solution of fluorosilicate salt, as described, for example, in US patent A-5157191 or WO-A-0029511. Examples of suitable dewaxing catalysts described above are silica bound and dealuminated Pt / ZSM-5, silica bound and dealuminated Pt / ZSM-35, which are described, for example, in WO-A-0029511 and EP-B 832171.

When using a dewaxing catalyst, the conditions of step (c) typically include an operating temperature in the range of 200 to 500 ° C., suitably 250 to 400 ° C. The preferred temperature is between 300 and 330 ° C. The hydrogen pressure is in the range from 10 to 200 bar, preferably from 40 to 70 bar, the weight feed rate (VSS) is in the range from 0.1 to 10 kg of oil per liter of catalyst per hour (kg / (l · h)) , it is advisable from 0.1 to 5 kg / (l · h), more suitably from 0.1 to 3 kg / (l · h) and the ratio of hydrogen to oil is in the range from 100 to 2000 liters of hydrogen per liter of oil.

It was found that when the dewaxing stiffness exceeds approximately 30% per passage in step (c), the yield and pour point decrease exponentially until the next plateau is reached at a pour point in the range from -50 to -60 ° C. . In addition, it was found that the isomerized residual product obtained in the Fischer-Tropsch synthesis has a pour point below -28 ° C, which indicates a much smaller effect of reducing the pour point, or the absence of a drop in pour point.

However, at the same time, it was found that increased amounts of the isomerized residual product obtained in the Fischer-Tropsch synthesis can be added with such a low pour point to the mineral component (a) of the base oil in order to achieve high viscosity without increasing the cloud point at a temperature environment or above it.

In step (d), the product of step (c) is usually fed to a vacuum column, where various fractions of the distillate base oil are recovered. These distillate base oil fractions can be used to form lubricant base oil mixtures, or they can be cracked to form low boiling products such as diesel or naphtha. The residual product taken from the vacuum column contains a mixture of high boiling hydrocarbons and is used to obtain component (b) of the present invention.

In addition, the product obtained in step (c) may also be subjected to further processing, such as solvent dewaxing. The product obtained in the method according to the invention can be further purified, for example, during processing with clay or by contacting with activated carbon, as described, for example, in US patent A-4795546 and EP-A-712922, in order to improve stability. In addition, it was found that the saturation level, pour point and viscosity index (VI) of the base oils of groups II and III can be weakened using the mixtures according to the invention, since the addition of component (b), due to the high level of saturation, can be achieved very low pour point and high VI to obtain the specified values of kinematic viscosity at 100 ° C (KV 100), pour point and IV. Accordingly, the cracking rigidity of mineral oil can be reduced, which leads to an improvement in the yield of products from raw materials — mineral oil. Therefore, the present invention also relates to a method for producing a lubricating base oil having a saturated content of more than 90 wt.%, A sulfur content of less than 0.03 wt.%, A viscosity index between 80-150, which includes (a) contacting the feed, produced from mineral oil, as described above, with hydrogen in the presence of a hydrogenation catalyst, and (b) mixing the resulting product with component (b) produced in the Fischer-Tropsch synthesis, as described above.

In addition, formulations based on API Group II oils with a small amount of additives and therefore with a low degree of thickening, for example, such as SAE 40 or 50 single-grade motor oils, can be prepared by mixing according to the invention. Another method of preparation is difficult, since the kinematic viscosity of SAE oils is required to be at least 12.5 mm ² / s (cSt) or 16.3 mm ² / s (cSt) at 100 ° C, respectively.

The product obtained in the method according to the invention can be further purified, for example, during processing with clay or by contacting with activated carbon, as described, for example, in US patent A-4795546 and EP-A-712922, in order to improve the stability of the base oil .

The invention will now be illustrated by the following non-limiting examples.

Examples

Obtaining catalyst dewaxing

MTW type zeolite crystallites were prepared as described in Verified synthesis of zeolitic materials, published in Micropores and mesopores materials, Volume 22 (1998), pages 644-645, using tetraethylammonium bromide as a matrix. ZSM-12 particle size, evaluated visually using scanning electron microscopy (SEM), is between 1 and 10 microns. The average crystallite size found using the method of broadening the lines of x-ray diffraction is 0.05 μm. The crystallites thus obtained are subjected to extrusion with a binder — silicon dioxide (10 wt.% Zeolite, 90 wt.% A binder — silicon dioxide). The extrudate is dried at 120 ° C, and a solution of (NH ₄ ) ₂ SiF ₆ (45 ml of a 0.019 N solution per 1 gram of zeolite crystallites) is poured onto it. The mixture is then heated at 100 ° C. and vigorously irrigated for 17 particles with gentle stirring above the extrudate particles. After filtration, the extrudate is washed twice with deionized water, dried for 2 hours at 120 ° C and then calcined for 2 hours at 480 ° C.

The extrudate particles thus obtained are impregnated with an aqueous solution of platinum tetramine hydroxide, followed by drying (2 hours at 120 ° C) and calcined (2 hours at 300 ° C). The catalyst is activated by reducing platinum in a stream of hydrogen (100 L / hr) at 350 ° C. for 2 hours. The resulting catalyst contains 0.35 wt.% Pt supported on dealuminated silica bound MTW zeolite.

Example 1. Obtaining component (b) produced in the Fischer-Tropsch synthesis

The wax produced in the Fischer-Tropsch synthesis, which was processed during the hydrocracking / hydroisomerization process and further contained at least 80 wt.% Of isoparaffins and had the characteristics indicated in Table 1, was distilled to obtain the light base oil precursor fraction boiling off mainly between 390 and 520 ° C and a residual heavy fraction boiling above 520 ° C.

Table 1 Density at 70 ° C [kg / l] 0.7874 T10% [° C] 346 T50% [° C] 482 T90% [° C] 665 Pour point [° C] 48

The residual base oil precursor fraction is contacted with the above dewaxing catalyst. The dewaxing is carried out under conditions: a hydrogen pressure of 40 bar, VSSP = 1 kg / (l / h), a temperature of 340 ° C and a supply of gaseous hydrogen of 700 norms. l / kg of raw materials. The dewaxed oil is separated by distillation into a light base oil component and a heavy base oil component having the characteristics shown in table 2.

table 2 Heavy base oil The boiling range of the base oil component (° C) > 520 The output per raw material dewaxing,% 54.3 Density at 20 ° C (kg / l) 0.8336 Pour point (° C) -42 Kinematic viscosity at 100 ° C (cSt) 15.95 Viscosity index 168 Average molecular weight 692

Example 2

An API Group I high viscosity cylinder oil made from mineral oil, having a viscosity index of 95 and a kinematic viscosity at 100 ° C of 32 cSt, is mixed with a number of Fischer-Tropsch base oil components according to the invention (A, B and C), as well as with a number of components that do not correspond to the invention (comparative A and B), which were obtained at a less stringent stage of dewaxing.

The limit at which the mixture still has a negative cloud point and therefore is transparent and bright is determined by compiling several mixtures with different concentrations. The limit to which a component made in the Fischer-Tropsch synthesis can be added to obtain a clear and bright mixture after several days at ambient temperature is indicated as a clear and bright limit. The limit for bottoms products made in the Fischer-Tropsch synthesis and not corresponding to the present invention, that is, having a ratio of wt.% Carbon atoms in groups CH ₂ > 4 (for all C atoms) to wt.% Carbon atoms in isopropyl groups above 8 , 2, was clearly lower than for the components produced in the Fischer-Tropsch synthesis according to the invention.

Table 3 BUT AT FROM Comp. A Comp. B KB at 40 ° C 173.1 192.3 229.3 259.7 241.0 HF at 100 ° C 20.48 22.49 25.15 26.63 26.49 The cloud point of the Fischer-Tropsch base oil component fifteen 26 34 not identified 36 Base fluid component pour point (° C) -42 -45 -thirty -6 -6 CH ₂ > 4 / sum (wt.%) 12.0 14.9 17.4 21 19.5 Carbon atoms in isopropyl groups 3.0 2,4 2,4 1.96 2.1 The ratio of wt.% Carbon atoms in CH ₂ > 4 groups (for all C atoms) to wt.% Carbon atoms in isopropyl groups 4.0 6.2 7.2 10.7 9.3 Transparent and light limit (wt.%) 38 28 25 fifteen twenty

Example 3. Mixtures of API Group II Base Oil

An additional series of mixtures were prepared with API group II base oil and a Fischer-Tropsch base oil component according to the invention. Characteristics of the starting components are shown in table 4.

Table 4 ASTM standard Group II base oil Fischer-Tropsch Heavy Base Oil KB at 40 ° C D 445 110 not identified HF at 70 ° C D 445 not identified 43.21 HF at 100 ° C D 445 12,2 19.0 IW D 2270 97 not identified Sulfur (mass% by X-ray analysis) D 2622 0.01 <0,0005 (detection limit) Aromatic compounds (wt.%) 4.0 0.2 The cloud point of the Fischer-Tropsch base oil component not identified > 40 TTRRT D 1500 0.5 Less than 0.5

Mixtures were prepared with an increasing amount of base oil and Group II base oil in order to determine at what ratio of these components the cloud point would become positive. These mixtures were obtained by heating the mixture of the two components to approximately 50 ° C with stirring until the mixture became clear and light, followed by cooling to room temperature (25 ° C). Then these mixtures are kept at room temperature for 24 hours, 3 and 7 days, and during this period the appearance of the mixtures is controlled (see table 5).

Table 5 The ratio of the base oil of Group II to Fischer-Tropsch oil Appearance after 24 hours at room temperature (25 ° C) Appearance after 3 days at room temperature (25 ° C) Appearance after 7 days at room temperature (25 ° C) 90:10 transparent and bright transparent and bright transparent and bright 88:12 transparent and bright transparent and bright transparent and bright 85:15 transparent and bright Lightly foggy foggy 80:20 transparent and bright Lightly foggy foggy 75:25 transparent and bright foggy foggy 70:30 foggy foggy foggy

The above results clearly demonstrate that, according to the invention, homogeneous mixtures can be obtained containing large amounts of a component of the residual paraffin base oil produced in the Fischer-Tropsch synthesis. Similar characteristics were found for mixtures containing Group III base oils made from mineral oil, although the additive limit at which a negative cloud point can be obtained is limited to approximately 5% by weight of Fischer-Tropsch synthesis components.

Claims (9)

1. A lubricating base oil mixture containing
(a) a mineral oil base oil having a saturated content of more than 90 wt.%, a sulfur content of less than 0.03 wt.% and a viscosity index between 80 and 150, and
(b) a paraffin base oil component having a viscosity at 100 ° C. of 7 to 30 cSt (7 to 30 mm ² / s), where component (b) is an isomerized residual product obtained in a Fischer-Tropsch synthesis and having a ratio the percentage of secondary methylene carbon atoms that are four or more carbon atoms away from the end group and branch to the percentage of isopropyl carbon atoms found using the ¹³ C-NMR method is less than 8.2;
moreover, the base oil mixture has a cloud point below 0 ° C and the kinematic viscosity at 100 ° C is greater than 12.0 cSt. 2. The base oil mixture according to claim 1, in which component (a) of the base oil of mineral origin is present in an amount of from 40 wt.% To 95 wt.%, Calculated on the total weight of the oil mixture. 3. The base oil mixture according to claim 1 or 2, which has a viscosity index of greater than 95. 4. The base oil mixture according to claim 1 or 2, in which the viscosity index of component (a) is between 100 and 110. 5. The base oil mixture according to claim 1 or 2, wherein component (a) of the base oil is an API group II base oil and / or group III API as defined in API publication 1509. 6. The base oil mixture according to claim 1 or 2, in which component (b) has a pour point below -28 ° C. 7. A method of obtaining a mixture of lubricating base oil, which includes mixing
(a) a mineral oil-derived base oil having a saturated content of more than 90 wt.%, a sulfur content of less than 0.03 wt.% and a viscosity index between 80 and 150, and
(b) a paraffin base oil component having a viscosity at 100 ° C. of 7 to 30 cSt (7 to 30 mm ² / s), where component (b) is a Fischer-Tropsch derived isomerized residual product and having a ratio the percentage of secondary methylene carbon atoms that are four or more carbon atoms away from the end group and branch to the percentage of isopropyl carbon atoms found using the ¹³ C-NMR method is less than 8.2; moreover, the base oil mixture has a cloud point below 0 ° C and the kinematic viscosity at 100 ° C is greater than 12.0 cSt. 8. The method according to claim 7, in which component (b) has an average degree of branching in the molecules of more than 10 alkyl branches per 100 carbon atoms. 9. The method according to any one of claims 7 to 8, in which the paraffin component (b) of the base oil is a heavy residual fraction after distillation of the wax produced in the Fischer-Tropsch synthesis, or paraffin raffinate feedstock obtained by:
(a) hydrocracking / hydroisomerization of a Fischer-Tropsch derived feed in which the weight ratio of compounds having at least 60 or more carbon atoms and compounds having but at least 30 carbon atoms in the feed produced Fischer-Tropsch synthesis, is at least 0.2 and in which at least 30 wt.% of the compounds in the feed produced in the Fischer-Tropsch synthesis has at least 30 carbon atoms;
(b) separating the product of step (a) into one or more distillate fractions of low boiling fractions, a broad fraction of the base oil precursor, and a heavy fraction so that the boiling point of 90 wt.% of the base oil precursor fraction is between 350 ° C. and 550 ° C. ;
(c) treating the broad base oil precursor fraction obtained in step (b) in the step of lowering the pour point; and
(d) a heavy residual fraction is isolated by distillation of the product of step (c).

Images