RU2637125C2 - Residual base oil producing method - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: residual base oil producing method includes, at least, the following steps: (a) providing a paraffinic raffinate of a mineral high-viscosity cylinder oil; (b) combining the paraffinic raffinate of the mineral high-viscosity cylinder oil provided in step (a) with the residual base oil produced by the Fischer-Tropsch method subjected to catalytic dewaxing to prepare the mixture; and (c) dewaxing the mixture produced in step (b) with a solvent to produce the residual base oil. The weight ratio of the paraffinic raffinate of the mineral high-viscosity cylinder oil to the residual base oil produced by the Fischer-Tropsch method subjected to catalytic dewaxing in step (b) is in the range of 75:25 to 35:65. Another aspect of the present invention relates to the residual base oil that can be produced by this method.

EFFECT: lower costs.

12 cl, 1 dwg, 5 tbl, 1 ex

Description

The present invention relates to a method for producing residual base oil and to a residual base oil that can be obtained by this method.

It is known to use high viscosity base oils (typically 20 to 25 mm ² / s) obtained by the Fischer-Tropsch process to improve the lubricating properties of base oils, such as pour point and cloud point. High viscosity base oils, also known as high viscosity cylinder base oils (Brightstock), obtained by Fischer-Tropsch synthesis, often have a cloudy appearance, which is usually due to the presence of a small number of particles of microcrystalline wax.

WO 2007/003623 discloses a method for producing a composition of high viscosity cylinder base oils containing a paraffin base oil component having a viscosity at 100 ° C of 8 to 25 mm ² / s, and a component of deasphalted residual mineral oil in an amount of 40% to 99% based on the total weight of the oil composition. In the method of WO 2007/003623, the catalytic dewaxing of a paraffin component of a precursor of a Fischer-Tropsch derived base oil results in the formation of a cloudy paraffin component of a Fischer-Tropsch derived base oil. The amount of wax present in the paraffin component of the Fischer-Tropsch derived base oil, resulting in a hazy appearance, is insufficient for the purpose of effecting the dewaxing of the paraffin component of the base oil obtained with the Fischer-Tropsch solvent in an efficient manner. Therefore, a mixture of the turbid, Fischer-Tropsch derived paraffin component of the base oil with a residue of mineral origin at a temperature above 50 ° C is made up to obtain a clear composition.

The purpose of the present invention is to develop a more effective method for producing a transparent and bright residual base oil.

An additional objective of the present invention is to develop an alternative method for producing a transparent and bright residual base oil.

Another objective of the present invention is to obtain a transparent and bright residual base oil using a significant proportion of the high viscosity base oil produced by the Fischer-Tropsch process.

The above and other objectives are achieved according to the present invention by providing a method for producing a residual base oil, which includes at least the following steps:

(a) provide a paraffin raffinate of mineral high viscosity cylinder oil;

(b) combining the paraffin raffinate of the mineral high-viscous cylinder oil provided in step (a) with the Fischer-Tropsch produced catalytic dewaxing residual base oil to form a mixture; and

(c) the mixture obtained in step (b) is dewaxed with a solvent to obtain a residual base oil.

To date, according to the present invention, it has been unexpectedly discovered that by solvent dewaxing of a mixture containing paraffinic raffinate of mineral high viscosity cylinder oil and produced by the Fischer-Tropsch method of the residual base oil subjected to catalytic dewaxing, it is easy to eliminate turbidity present in the mixture.

It was found that required at least 5% of the mass. wax in a mixture of paraffinic raffinate of mineral high-viscosity cylinder oil and produced by the Fischer-Tropsch method of the residual base oil subjected to catalytic dewaxing in order to carry out the solvent dewaxing stages in an optimal manner. The amount of wax present only in the Fischer-Tropsch obtained residual base oil subjected to catalytic dewaxing is insufficient for the purpose of dewaxing with a solvent of said base oil separately in an effective manner. The amount of wax present in the obtained by the Fischer-Tropsch method of the residual base oil subjected to catalytic dewaxing is less than 0.1% of the mass. based on the total amount of Fischer-Tropsch obtained residual base oil subjected to catalytic dewaxing.

The solvent dewaxing of the mixture containing the paraffinic raffinate of the mineral high-viscosity cylinder oil and the Fischer-Tropsch obtained residual base oil subjected to catalytic dewaxing eliminates the difficulty of removing turbidity from the separately taken Fischer-Tropsch residual base oil subjected to catalytic dewaxing wax in a mixture (at least 5% by weight), resulting in increased efficiency tee.

An additional advantage of the present invention is that a large amount of a high viscosity Fischer-Tropsch derived base oil can be used in the mixture to produce a clear and bright high viscosity base oil.

Another advantage of the present invention is that a clear and bright residual base oil is obtained having a high viscosity, low pour point and low cloud point.

In step (a) of the method according to the present invention, a paraffin raffinate of a mineral high viscosity cylinder oil is provided. Various methods are known in the art for providing a paraffinic raffinate of mineral high viscosity cylinder oil.

Suitably, paraffin raffinate of high viscosity mineral cylinder oil is prepared using the following steps:

(aa) provide a vacuum residue of mineral origin;

(bb) carry out the step of deasphalting the vacuum residue of mineral origin to obtain deasphalted oil; and

(cc) the solvent is extracted with deasphalted oil to obtain a residual aromatic extract and paraffinic raffinate of mineral high-viscosity cylinder oil.

In step (aa), a vacuum residue of mineral origin is provided. The vacuum residue of mineral origin provided in step (aa) may be the residual bottom fraction of the vacuum distillation of crude oil. The preferred property of the vacuum residue of mineral origin is that 90% of the mass. boils above 500 ° C, more preferably above 520 ° C.

In step (bb), a vacuum residue of mineral origin is deasphalted to produce a deasphalted oil. Deasphalted oil is a product of the stage of the deasphalting process, during which asphalt is removed from the vacuum residue of mineral origin. Deasphalting processes are well known and described, for example, in the book Lubricant base oil and wax processing, Avilino Sequeira, Jr., Marcel Dekker, Inc, New York, 1994, ISBN 0-8247-9256-4, pages 53-80. Typically, a light hydrocarbon liquid solvent, such as propane, is used in the deasphalting process for asphalt compounds. A preferred property of deasphalted oil is that 90% of the mass. boils above 470 ° C, more preferably above 490 ° C.

In step (cc), the deasphalted oil is subjected to solvent extraction to obtain a residual aromatic extract and paraffinic raffinate of mineral high-viscosity cylinder oil.

Deasphalted oil is subjected to a solvent extraction process to remove certain aromatic compounds. Solvent extraction processes are known in the art, and therefore are not discussed in detail here. Typical solvent extraction processes are described, for example, in chapter 5 of the book "Lubricant base oil and wax processing", Avilino Sequeira, Jr., Marcel Dekker, Inc, New York, 1994, ISBN 0-8247-9256-4.

Usually, after solvent extraction of the deasphalted oil, the solvent is distilled off from the paraffin raffinate of the mineral high viscosity cylinder oil, and the residual aromatic extract containing mainly aromatic compounds, some dissolved paraffinic raffinate of the mineral high viscosity cylinder oil and some wax are sent to the separation unit. This method is described, for example, in US patent 4,592,832.

The paraffinic raffinate of the mineral high-viscous cylinder oil obtained in stage (a) is the resulting phase of the extracted deasphalted oil containing mainly unsaturated hydrocarbon molecules obtained in stage (cc). Suitably, the number of molecules of unsaturated hydrocarbons is from 50 to 60% of the mass. based on the total amount of paraffinic raffinate of mineral high-viscosity cylinder oil.

Suitably, the paraffin raffinate of the high viscosity mineral cylinder oil obtained in step (a) according to ASTM D-445 has a kinematic viscosity at 40 ° C. of 200 to 700 mm ² / s, preferably 300 to 600 mm ² / s , more preferably 400 to 600 mm ² / s, and most preferably 500 to 600 mm ² / s.

In addition, according to ASTM D-445, the kinematic viscosity of the paraffinic raffinate of the mineral high viscosity cylinder oil at 100 ° C is suitably 20 to 50 mm ² / s, preferably 30 to 50 mm ² / s, and more preferably 30 to 40 mm ² / s. Typically, the viscosity index of the paraffin raffinate of the mineral high viscosity cylinder oil is from 50 to 150, preferably from 70 to 120, more preferably from 80 to 100.

In step (b), the paraffinic raffinate of the mineral high viscosity cylinder oil provided in step (a) is combined with the Fischer-Tropsch process of the residual base oil subjected to catalytic dewaxing to form a mixture.

In an alternative embodiment of the method in accordance with the present invention, a portion of the deasphalted oil obtained in step (b), which was not subjected to the treatment in step (cc) with solvent extraction, is combined with the Fischer-Tropsch produced catalytic dewaxed residual base oil to obtain mixtures.

Suitably at least 20% of the mass. deasphalted oil, preferably at least 30% of the mass. deasphalted oil, and more preferably at least 50% of the mass. deasphalted oil is combined with the Fischer-Tropsch process produced by the residual base oil subjected to catalytic dewaxing to form a mixture.

The catalytic dewaxing residual base oil produced by the Fischer-Tropsch process used in step (b) is obtained from the Fischer-Tropsch process. The Fischer-Tropsch derived base oil is known in the art. The term "obtained by the Fischer-Tropsch method" means that the base oil is a product of synthesis by the Fischer-Tropsch method or obtained from such a product. The Fischer-Tropsch derived base oil may also be called GTL (gas-in-liquid) base oil.

Catalytic dewaxing of the residual base oil with a solvent will be rather difficult due to the fact that the amount of wax is so small, but much more important, that it will be very difficult to separate it on the filter cloth, since the wax has the consistency of chewing gum. The indicated “chewing gum” consistency is obtained as a result of the catalytic dewaxing step, which is necessary to obtain a high viscosity base oil synthesized by the Fischer-Tropsch method with a desired pour point. The product of the Fischer-Tropsch synthesis, from which the residual base oil is obtained, subjected to catalytic dewaxing, has an unfavorable pour point and is also heavy and, therefore, cannot be easily removed from the production equipment of the Fischer-Tropsch process.

The preparation of the Fischer-Tropsch-derived residual catalytic dewaxing base oil used in step (b) is described, for example, in documents WO 2007/003623 and WO 2007/003617.

The Fischer-Tropsch derived and catalytic dewaxing base oils of the present invention are typically a heavy base oil component containing carbon atoms up to C ₆₅ , typically in the range of at least C ₂₀ and not more than C ₆₅ , and a wax component comprising from at least 0.001% of the mass. and up to no more than 5% of the mass. usually up to not more than 1% of the mass., suitably up to not more than 0.1% of the mass. Typically, the amount of the wax component present in the Fischer-Tropsch obtained residual base oil subjected to catalytic dewaxing depends on the stringency of the pour point.

Obtained by the Fischer-Tropsch method and subjected to catalytic dewaxing turbid residual base oils of the present invention are at least partially or completely visually opaque at ambient temperature. Therefore, it will be apparent to one skilled in the art that the catalytic dewaxing residual base oils obtained by the Fischer-Tropsch process used in the present invention contain sufficient additional heavy components (such as wax) to impart a visible clouding to the appearance of the oil. Typically, the amount of wax that gives a visible clouding, is from 0.01% of the mass. up to 0.1% of the mass. based on the total amount of Fischer-Tropsch obtained residual base oil subjected to catalytic dewaxing. For this reason, the base oils of the present invention will not traditionally be described as “clear” or “bright”.

Suitably, the Fischer-Tropsch derived catalytic dewaxed residual base oil used in step (b) typically has a kinematic viscosity at 40 ° C. of above 80 mm ² / s, suitably above 100 mm ² / s according to ASTM D-445 standard. Typically, the kinematic viscosity at 40 ° C. of the Fischer-Tropsch prepared catalytic dewaxing base oil of the present invention is below about 300 mm ² / s.

In addition, according to ASTM D-445, the kinematic viscosity at 100 ° C of the Fischer-Tropsch derived base oil is from 12 to 50 mm ² / s, preferably from 15 to 35 mm ² / s, more preferably from 18 to 30 mm ² / s and most preferably from 18 to 25 mm ² / s.

The Fischer-Tropsch derived catalytic dewaxing residual base oil preferably has a ASTM D-5950 pour point of below 0 ° C, more preferably below -5 ° C, and most preferably below -10 ° C.

Typically, a cloudy paraffin base oil has a cloud point of 15 ° C or higher. Preferably, the Fischer-Tropsch derived catalytic dewaxing residual base oil has a cloud point of ASTM D-5950 above 15 ° C, more preferably above 20 ° C, more preferably above 25 ° C and most preferably above 30 ° C.

Suitably, the mixture obtained in step (b) contains from 10 to 80% by weight, preferably from 20 to 70% by weight, more preferably from 25 to 65% by weight. produced by the Fischer-Tropsch method of the residual base oil subjected to catalytic dewaxing.

Preferably, the weight ratio of the paraffinic raffinate of the mineral high viscosity cylinder oil to the Fischer-Tropsch obtained residual base oil subjected to catalytic dewaxing in step (b) of the present method is in the range from 75:25 to 35:65, more preferably in the range from 65:35 to 35:65, most preferably 55:45 to 35:65.

The mixture obtained in stage (b) typically contains a fraction in which 50% boils above 450 ° C, preferably in which 50% boils above 550 ° C. It is the high boiling fraction that produces viscous base oils.

Typically, the mixture obtained in step (b) contains a fraction that boils 90% below 820 ° C.

The wax content in the mixture is preferably below 20% by weight, more preferably below 10% by weight. The lower limit is preferably above 4% of the mass.

In step (c), the solvent dewaxing step for the mixture prepared in step (b) is carried out to obtain a residual base oil.

Solvent dewaxing methods are known in the art and therefore are not described in detail here. Typical solvent dewaxing methods are described, for example, in Lubricant Base Oil and Wax Processing, Avilino Sequeira, Jr, Marcel Dekker Inc., New York, 1994, Chapter 7.

In a preferred embodiment, the method in accordance with the present invention includes an additional step in which heteroatom compounds are separated from the residual base oil obtained in step (c).

Preferably, the residual base oil obtained in step (c) comprises sulfur and nitrogen compounds contained in amounts of less than 50 ppm by mass, more preferably less than 20 ppm by mass, even more preferably less than 10 ppm by mass. Most preferably, it contains sulfur and nitrogen in amounts generally below the detection limits, which are currently 5 ppm for sulfur and 1 ppm for nitrogen when used to determine, for example, X-ray analysis methods or a nitrogen detection method using Antek analyzer. However, sulfur can be introduced using sulfonated hydrocracking / hydrodewaxing catalysts and / or sulfonated catalytic dewaxing catalysts. If desired, a final post-treatment can be carried out in order to separate sulfur and nitrogen compounds from the residual base oil. Examples of suitable post-treatment methods are so-called sulfuric acid treatment processes, mild hydrotreatment, or hydrogenation and adsorption processes. Sulfuric acid refining is described, for example, in General Textbook "Lubricant Base Oil and Wax Processing", Avilino Sequeira, Jr, Marcel Dekker Inc., New York, 1994, Chapter 6, pages 226-227. Moderate hydrotreating is suitably carried out at a temperature of from 180 to 380 ° C, a total pressure of from 10 to 250 bar, and preferably above 100 bar, and more preferably from 120 to 250 bar. The value of WHSV (mass hourly space velocity) is in the range from 0.3 to 2 kg of oil per liter of catalyst per hour (kg / l⋅h).

An additional aspect of the present invention relates to residual base oil, which can be obtained by the method according to the present invention.

The turbidity-free residual base oil will preferably have a kinematic viscosity at 100 ° C according to ASTM D-445 of 12 to 50 mm ² / s, preferably 15 to 35 mm ² / s, more preferably 18 to 30 mm ² / s and most preferably from 18 to 25 mm ² / s.

The viscosity index of the residual base oil is preferably greater than 95, preferably greater than 100.

The pour point of the residual base oil according to ASTM D-5950 is below -5 ° C, preferably below -10 ° C and more preferably below -15 ° C.

The turbidity-free residual base oil can also be characterized by its cloud point. The residual base oil preferably has a ASTM D-5950 cloud point below -10 ° C, more preferably below -15 ° C, and most preferably below -20 ° C.

The figure 1 schematically shows the technological scheme of the method according to the present invention.

For the purposes of this description, a uniform position number will be assigned to the line, as well as to the flow passing through the given line.

The technological scheme as a whole is correlated with the position number 1.

From the raw material 10, a vacuum residue 20 of mineral origin is isolated in the form of crude oil by vacuum distillation in a vacuum distillation unit 2. The vacuum residue 20 of mineral origin is deasphalted in the reactor 3 to obtain deasphalted oil 30. Residual aromatic extract 40 and paraffin raffinate 50 of high-viscosity mineral cylinder oil 50 are recovered from deasphalted oil 30 in the reactor 4. The residual aromatic extract 40 and the solvent are withdrawn from reactor 4 as a stream 40 to set 5 allocation. The stream containing the Fischer-Tropsch-produced turbid residual base oil 60 subjected to catalytic dewaxing is combined with a paraffin raffinate 50 of mineral high viscosity cylinder oil before entering reactor 6, in which the combined streams are dewaxed with a solvent to obtain a residual base oil 70 and a waxy product ( mixed gachi) 80. Sulfur and nitrogen in the form of hydrocarbon compounds are separated from the residual base oil 70 by final purification in the reactor 7.

The present invention is described further with reference to the following examples, which are not intended to limit the scope of the present invention in any way.

Example 1

Preparation of paraffin raffinate mineral high viscosity cylinder oil

The paraffin raffinate of high-viscosity mineral cylinder oil was obtained from Shell Pernis Refinery (Pernis, Netherlands). Paraffin raffinate of mineral high-viscosity cylinder oil was prepared as a result of the deasphalting stage of a vacuum residue of mineral origin (high-sulfur Middle Eastern oil, for example, Arab Light brand). The resulting deasphalted oil was extracted with furfural using a solvent to fresh feed ratio of 3.8 w / w (min. 2.4 w / w, max. 6.3 w / w) for obtaining residual aromatic extract and paraffinic raffinate of mineral high-viscosity cylinder oil. Methods of solvent extraction with furfural are known in the art and are described, for example, in chapter 5 of the book "Lubricant base oil and wax processing", Avilino Sequeira, Jr., Marcel Dekker, Inc, New York, 1994, ISBN 0-8247-9256- four. The properties of the obtained paraffinic raffinate of mineral high-viscosity cylinder oil are shown in table 1.

Preparation of Fischer-Tropsch-derived residual base oil subjected to catalytic dewaxing

The Fischer-Tropsch synthesized residual base oil subjected to catalytic dewaxing was prepared by the method described in Example 1 of WO 2007/003623. The properties of the obtained residual material subjected to catalytic dewaxing are shown in tables 2 and 3.

Cooking Residual Base Oil

Several mixtures were prepared by mixing the Fischer-Tropsch obtained residual base oil and paraffinic raffinate of high viscosity mineral cylinder oil in various ratios (see table 4: experiments A, B, C and D) at 60 ° C for 15 minutes.

The resulting mixtures were processed in the next following conventional solvent dewaxing step.

Samples of the obtained mixtures (120 g) were dissolved in a certain amount of a mixture of toluene and methyl ethyl ketone (50/50) in a ratio of 4/1. The solution was cooled to the desired dewaxing temperature (-20 ° C), allowing the sediments to be precipitated, and the liquid phase was separated by filtration using filter paper with a backing sheet (Whatman No. 41, catalog number: 1441090, Whatman Department of GE Health Sage). The solvent was removed from the resulting residual base oil in vacuo to a content of less than 1000 ppm.

The properties of the resulting residual base oils are shown in table 5.

Discussion

The results shown in table 5 show that the solvent dewaxing of the mixtures obtained in experiments A-D in accordance with the present invention, leads to a transparent and bright residual base oils. In addition, when a significant portion of the Fischer-Tropsch produced residual base oil subjected to catalytic dewaxing was added to the mixture (see, for example, experiment D), clear and bright base oils were still obtained. In addition, when a significant proportion of the Fischer-Tropsch synthesized residual base oil subjected to catalytic dewaxing was added to the mixture (see experiments A-D in table 4), the pour points of the residual base oils improved (see table 5) compared to the pour point obtained by the Fischer-Tropsch method of the residual base oil subjected to catalytic dewaxing (see table 2).

Claims (18)

1. A method of obtaining a residual base oil, comprising at least the following stages: (a) provide a paraffin raffinate of mineral high viscosity cylinder oil; (b) combining the paraffin raffinate of the mineral high-viscous cylinder oil provided in step (a) with the Fischer-Tropsch produced catalytic dewaxing residual base oil to form a mixture; and (c) subjecting the mixture obtained in step (b) to a dewaxing solvent to obtain a residual base oil, wherein the mass ratio of the paraffin raffinate of the mineral high viscosity cylinder oil to the Fischer-Tropsch produced residual base oil subjected to catalytic dewaxing in step (b) It ranges from 75:25 to 35:65. 2. The method according to p. 1, in which the paraffin raffinate of mineral highly viscous cylinder oil is obtained using the following stages: (aa) provide a vacuum residue of mineral origin; (bb) carry out the step of deasphalting the vacuum residue of mineral origin to obtain deasphalted oil; and (cc) the solvent is extracted with deasphalted oil to obtain a residual aromatic extract and paraffinic raffinate of mineral high-viscosity cylinder oil. 3. The method according to p. 1, in which the paraffin raffinate of mineral high-viscosity cylinder oil provided in stage (a) has a kinematic viscosity at 100 ° C of 20 to 50 mm ² / s, preferably from 30 to 50 mm ² / s, more preferably from 30 to 40 mm ² / s. 4. The method according to p. 1, in which the produced by the Fischer-Tropsch method residual base oil, subjected to catalytic dewaxing, used in stage (b), has a kinematic viscosity at 100 ° C, comprising from 12 to 50 mm ² / s, preferably from 15 to 35 mm ² / s, more preferably 18 to 30 mm ² / s, and most preferably 18 to 25 mm ² / s. 5. The method according to p. 1, in which the produced by the Fischer-Tropsch method residual base oil subjected to catalytic dewaxing used in stage (b) has a pour point below 0 ° C, preferably below -5 ° C, more preferably below -10 ° C. 6. The method according to p. 1, in which the produced by the Fischer-Tropsch method residual base oil subjected to catalytic dewaxing used in stage (b) has a cloud point above 15 ° C, preferably above 20 ° C, more preferably above 25 ° C and most preferably above 30 ° C. 7. The method according to p. 1, in which the mixture obtained in stage (b) contains from 10 to 80 wt. -%, preferably from 20 to 70 wt. -%, more preferably from 25 to 65% of the mass. produced by the Fischer-Tropsch method of the residual base oil subjected to catalytic dewaxing. 8. The residual base oil obtained by the method according to any one of paragraphs. 1-7. 9. The residual base oil according to claim 8, having a kinematic viscosity at 100 ° C. of 12 to 50 mm ² / s, preferably 15 to 35 mm ² / s, more preferably 18 to 30 mm ² / s and most preferably from 18 to 25 mm ² / s. 10. The residual base oil according to claim 8, having a viscosity index of greater than 95, preferably greater than 100. 11. The residual base oil according to claim 8, having a pour point below -5 ° C, preferably below -10 ° C, more preferably below -15 ° C. 12. The residual base oil according to any one of paragraphs. 8-11, having a cloud point below -10 ° C, preferably below -15 ° C, more preferably below -20 ° C.

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