RU2671862C2 - Process for preparing heavy base oil - Google Patents

Abstract

FIELD: technological processes.SUBSTANCE: present invention relates to a process for producing a heavy base oil that can be used in lubricating oils for protecting internal combustion engines in motor vehicles. Process includes steps of: (a) providing a hydrocarbonaceous feedstock which contains at least 50 % by weight of hydrocarbons boiling above 460 °C, nitrogen in amount in the range of 800–2,500 ppm, and sulphur in an amount in the range of 1.5–4.0 % wt; (b) hydrotreating the hydrocarbonaceous feedstock with a hydrotreating catalyst in the presence of a hydrogen-containing gas under hydrotreating conditions to obtain a hydrotreated product, which contains nitrogen in an amount in the range of 30–80 ppm and sulphur in an amount in the range of 200–450 ppm; (c) removing at least 50 % of the NHand HS, which is present in the hydrotreated product obtained in step (b); (d) catalytically dewaxing at least part of the hydrotreated product as obtained in step (c) with a dewaxing catalyst in the presence of a hydrogen-containing gas under catalytic dewaxing conditions to obtain a dewaxed product, which dewaxing catalyst comprises a group VIII metal hydrogenation component, dealuminated aluminosilicate zeolite crystallites and a low acidity refractory oxide binder material which is essentially free of alumina; (e) hydrofinishing at least part of the dewaxed product obtained in step (d) with a hydrofinishing catalyst in the presence of a hydrogen-containing gas under hydrofinishing conditions to obtain a heavy base oil; and (f) recovering the heavy base oil.EFFECT: disclosed process allows to obtain a base oil in high yield.15 cl, 7 tbl, 6 ex

Description

FIELD OF THE INVENTION

The present invention relates to a method for producing a heavy base oil. State of the art

The main use of base oil is its use in lubricating oils, such as motor oils, to protect an internal combustion engine in motor vehicles. Typically, lubricating oils consist mainly of base oil and a variety of additives to obtain the desired characteristics.

Light lubricating base oils are mainly used in automotive applications, and heavy lubricating base oils are used in heavy duty applications such as ship engines and industrial processes.

The base oils used in lubricating oils are obtained on a large scale by initially hydrotreating a vacuum gas oil distillate and / or deasphalted oil, followed by catalytic dewaxing and final hydrotreating of a hydrotreated liquid product or fraction of 370 ° C plus (boiling above 370 ° C) hydrotreated liquid product. Usually at the stage of catalytic dewaxing, a dewaxing catalyst is used - a noble metal. It is well known that dewaxing catalysts - noble metals are poisoned with organic nitrogen and sulfur compounds, and therefore it is necessary to use the stage of strict hydrotreating in order to sufficiently reduce the content of organic nitrogen and sulfur compounds in the hydrotreating reactor product boiling above 370 ° C.

Usually, in conditions of more stringent processing in the hydrotreating reactor, the quality of the hydrotreated product is improved to 370 ° C plus, which serves as a raw material for the base oil production unit. However, more stringent hydrotreating means that the yield of hydrotreated product 370 ° C plus becomes smaller, and the total hydrotreated product becomes lighter (the boiling point shifts due to tough hydrotreating), resulting in a significantly reduced ratio of heavy lubricating base oils to light lubricating base oils .

Decreasing the yield of heavy lubricating base oils is undesirable during a period of high demand for heavy base oils.

Therefore, the aim of the present invention is to develop a method for upgrading hydrocarbon feedstock in which a high yield of heavy lubricating base oils is achieved.

Disclosure of invention

This goal is achieved when the hydrocarbon feed is subjected to a refinement process that includes a certain sequence of process steps.

Accordingly, the present invention relates to a method for producing a heavy base oil, comprising the steps of:

(a) provide a hydrocarbon feed that contains at least 50% by weight of hydrocarbons boiling above 460 ° C, nitrogen in an amount in the range of 800 to 2500 ppm by weight, and sulfur in an amount in the range of 1.2 to 4, 0 mass %;

(b) hydrotreating said hydrocarbon feed using a hydrotreating catalyst or a hydrotreating catalyst bag in the presence of a hydrogen-containing gas under hydrotreating conditions to obtain a hydrotreated product that contains nitrogen in an amount in the range of 30 to 80 ppm by weight and sulfur in an amount in the range of 200 to 450 ppm by weight;

(c) removing at least 50% NH ₃ and H ₂ S that are present in the hydrotreated product obtained in step (b);

(d) catalytic dewaxing of at least a portion of the hydrotreated product obtained in step (c) is carried out using a dewaxing catalyst in the presence of a hydrogen-containing gas under catalytic dewaxing conditions to obtain a dewaxing product, said dewaxing catalyst containing a hydrogenating component of a Group VIII metal, crystallites of dealuminated aluminosilicate zeolite and a low acidity heat-resistant oxide binder material that is substantially free of holds alumina;

(e) final hydrotreating at least a portion of the dewaxed product obtained in step (d) using a final hydrotreating catalyst in the presence of a hydrogen-containing gas under final hydrotreating conditions to obtain a heavy base oil; and

(f) recovering said heavy base oil.

In accordance with the present invention, a high yield of heavy lubricating base oils can be obtained. The resulting heavy lubricating base oils include Group II and Group III lubricating base oils having a high ratio of heavy lubricating base oils to light lubricating base oils. These heavy lubricating base oils have a high viscosity, which makes them very attractive for use in heavy duty applications.

The implementation of the invention

The hydrocarbon feed provided in step (a) preferably contains more than 65%, but at least 50% by weight of hydrocarbons boiling above 460 ° C. Suitably, the hydrocarbon feed provided in step (a) comprises a fraction of 370 ° C plus, which has a viscosity at 100 ° C above 12 cSt, preferably at least 14 cSt.

The hydrocarbon feed contains nitrogen in an amount in the range of 800 to 2500 ppm by weight, preferably in the range of 1000 to 1500 ppm in weight, and sulfur in an amount in the range of 1.2 to 4.0 mass. %, preferably in the range from 1.5 to 3.0 mass. %

In the hydrocarbon feed provided in step (a), the ratio of the hydrocarbon fraction boiling in the range of 370 to 460 ° C. to the hydrocarbon fraction boiling in the range of 460 to 800 ° C. is preferably less than 10.

Examples of hydrocarbon feeds that can be used in accordance with the present invention are straight-run gas oil, hydrocracking gas oil, thermal cracking gas oil, coking gas oil, vacuum gas oil, light or heavy recycle gas oil, de-asphalted oil (DAO), or a combination of two or more of them . In addition, the hydrocarbon feed may be a paraffin raffinate after solvent extraction. At least a portion of the hydrocarbon feed provided in step (a) may suitably be a mixture obtained by mixing at least one distillate fraction, preferably a vacuum distillate fraction, and a deasphalted oil (DAO). Suitably, a DAO that can be used is obtained by deasphalting a residual hydrocarbon oil, preferably a vacuum residue. The deasphalting step may be carried out in any conventional manner. A well-known and suitable method of deasphalting is solvent deasphalting, which involves countercurrent treatment of the residual hydrocarbon oil with an extraction solvent. Typically, said extracting solvent is a light hydrocarbon solvent containing paraffin compounds having 3 to 8 carbon atoms, such as propane, butane, isobutane, pentane, isopentane, hexane, and mixtures of two or more thereof.

Preferred paraffinic hydrocarbons are those containing from 3 to 5 carbon atoms, with propane, butane, pentane and mixtures thereof being most preferred. It is convenient to carry out deasphalting solvent treatment in a contact apparatus with a rotating disk or in a column with plates, where the raw material of residual hydrocarbon oil enters the upper section and the extraction solvent enters this section. Lighter hydrocarbons present in the residual hydrocarbon oil dissolve in the extraction solvent and are discharged at the top of the apparatus. From this upper fraction, after extraction of the extraction solvent, DAO is obtained. Asphaltenes that are insoluble in the extraction solvent are discharged at the bottom of the unit. The prior art conditions are known under which deasphalting occurs. It is advisable that deasphalting is carried out with the ratio of the entire extraction solvent to the residual hydrocarbon oil equal to 1.5-8 by weight, pressure 0.1-5 MPa (1-50 bar) and a temperature of 50-230 ° C.

Deasphalted oil can be obtained by deasphalting the residual fraction, preferably a vacuum residual fraction containing hydrocarbons that have a boiling point of at least 460 ° C.

In step (b), the hydrocarbon feed is hydrotreated using a suitable hydrotreating catalyst or a hydrotreating catalyst bag in the presence of hydrogen containing gas under hydrotreating conditions to obtain a hydrotreated product that contains nitrogen in an amount ranging from 30 to 80 ppm by weight and sulfur in an amount in the range of 200 to 450 ppm by weight.

The catalyst or hydrotreating catalyst package that can be used in the first reaction zone in step (a), suitably, may be a desulfurization catalyst or a combination of desulfurization catalysts (including a possible demetallization catalyst or a combination of demetallization catalysts before the desulfurization step). The desulfurization catalyst may be any hydrodesulfurization catalyst that is known in the art or a combination of hydrotreating catalysts that can provide a hydrotreated effluent with a prescribed nitrogen and sulfur content. Typically, these catalysts comprise a Group VIII metal of the Periodic Table of the Elements and a metal compound of Group VIB of the Periodic Table of the Elements as hydrogenation components on a porous catalyst support, usually alumina or amorphous aluminosilicate. Well-known examples of suitable combinations of hydrogenation compounds are cobalt-molybdenum, nickel-molybdenum, nickel-tungsten and nickel-cobalt-molybdenum. A hydrodesulfurization catalyst is preferred which contains nickel and / or cobalt and molybdenum compounds as hydrogenation compounds. The hydrotreated product obtained in step (b) contains nitrogen in an amount in the range of 30 to 80 ppm by weight and sulfur in an amount in the range of 200 to 450 ppm in weight, which means that the hydrotreatment in step (b) is not hard hydrotreating process. Therefore, it is advisable to use hydrotreating catalysts or combinations of hydrotreating catalysts that do not have too high activity. Therefore, it is preferable to use an alumina-based hydrotreating catalyst. Preferably, said catalyst is substantially free of a cracking component. Particularly preferred is a catalyst or a combination of catalysts containing nickel and / or cobalt and molybdenum supported on alumina without a zeolite cracking compound.

In step (b), configurations with stacked layers can also be used in which two or more hydrotreating catalysts are stacked.

Suitably, the temperature in the hydrotreating step is in the range of 250 to 480 ° C, preferably in the range of 280 to 450 ° C, and more preferably in the range of 350 to 420 ° C.

Suitable absolute pressure of the hydrotreating process is in the range of 30 to 250 bar abs. Preferably, the absolute hydrotreating pressure is in the range of 110 to 180 bar abs, more preferably in the range of 120 to 170 bar abs.

A suitable weight hourly mass hourly space velocity (WHSV) is in the range from 0.2 to 10 h ^-1, preferably in the range from 0.2 to 2.0 h ^-1, and more preferably in the range from 0.2 to 1.0 h ^-1 .

It should be understood that the specific hydrotreatment conditions in step (a), inter alia, will depend on the catalyst used, as well as the sulfur content and nitrogen content of the hydrocarbon feed.

A suitable ratio of nitrogen to sulfur (N / S) in the hydrotreated product obtained in step (b) is in the range of 0.1 to 0.3, preferably in the range of 0.12 to 0.28.

In step (c), at least 50% NH ₃ and H ₂ S, which are present in the hydrotreated product obtained in step (b), are removed. Suitably, at least part of NH ₃ and H ₂ S, are present in the hydrotreated product obtained in step (b), is removed by stripping, preferably steam stripping. Suitably, this stripping is carried out at a temperature in the range from 100 to 350 ° C, preferably from 130 to 240 ° C, and a pressure in the range from 1 to 50 bar, preferably from 1.5 to 10 bar. Preferably at least 80%, more preferably at least 90%, and most preferably at least 95% of the NH ₃ and H ₂ S that are present in the hydrotreated product obtained in step (b) are removed from the hydrotreated product by stage (c). Preferably, in step (c), hydrocarbons boiling below 370 ° C are also separated from the hydrotreated product obtained in step (b).

Preferably, the entire hydrotreated product obtained in step (b) is subjected to step (c).

In step (d), at least a portion of the hydrotreated product obtained in step (c) is subjected to catalytic dewaxing using a dewaxing catalyst in the presence of a hydrogen-containing gas under conditions of catalytic dewaxing to obtain a dewaxing product, said dewaxing catalyst containing a hydrogenating component of a Group VIII metal , crystallites of dealuminated aluminosilicate zeolite and a low-acid heat-resistant oxide binder.

Preferably, the entire hydrotreated product obtained in step (c) is subjected to step (d).

Here, the expression catalytic dewaxing means the process of lowering the pour point of a lubricating base oil product by selectively converting hydrocarbon feed components that impart a high pour point to products that do not impart a high pour point. Products that impart high pour point are high melting point compounds. Such compounds are called waxes. Wax compounds include, for example, normal paraffins, isoparaffins and mono-ring compounds with a high melting point. Preferably, the pour point is reduced by at least 40 ° C, and more preferably at least 60 ° C. Thus, the hydrocarbon feed in the method according to the present invention may contain paraffin compounds that exhibit an undesirable high pour point. A small amount of these compounds can greatly affect the pour point. Accordingly, the feed may contain from less than 2% up to 80% of these paraffin compounds.

According to the invention, in the catalytic dewaxing step, the hydrotreated feed is contacted under catalytic dewaxing conditions with a catalytic composition containing a hydrogenating component of a Group VIII metal, crystallites of dealuminated aluminosilicate zeolite and a heat-resistant oxide binder with low acidity.

It was found that this type of dewaxing catalyst is very stable over time, even despite the high sulfur and nitrogen content found in the hydrocarbon feed. Examples of these catalysts are described in WO-A-9641849.

Preferably, the aluminosilicate zeolite crystallites have pores with diameters in the range of 0.35 to 0.80 nm. This diameter refers to the maximum pore diameter. As is generally accepted, pores in a molecular sieve are polygonal channels having a minimum and maximum pore diameter. For the purpose of the present invention, the maximum pore diameter is a critical parameter because it determines the size of the paraffin molecules that can enter the pores.

Examples of aluminosilicate zeolites that are suitable for use in the present invention are ferrierite, ZSM-5, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-35, ZSM-38, ZSM-48, ZSM-57 , SSZ-23, SSZ-24, SSZ-25, SSZ-26, SSZ-32, SSZ-33, and MCM-22, and mixtures of two or more of these zeolites. Preferably, the zeolite component is ZSM-5, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-35 or ZSM-48.

Preferably, the zeolite component in the dewaxing catalyst is present in an amount in the range from 10 to 50 mass. %, based on the total weight of the dewaxing catalyst. Preferably, the aluminosilicate zeolites have an MFI topology, for example, ZSM-5.

Preferably, small crystallites are used to achieve optimum catalytic activity. Preferably, crystallites less than 10 microns are used, and more preferably less than 1 microns. The practical lower limit is suitably 0.1 microns.

In addition, the dewaxing catalyst contains a low acidity heat resistant oxide binder material that is substantially free of alumina. Examples are low acidity heat resistant oxides such as silica, zirconia, titanium dioxide, germanium dioxide, boron oxide, and mixtures of two or more of them. The most preferred binder is silica. The ratio of the mass of the modified molecular sieve to the mass of the binder is suitably in the range from 05/95 to 95/05.

The dealumination of aluminosilicate zeolite leads to a decrease in the number of alumina fragments present in the zeolite, and therefore to a decrease in the molar fraction of alumina. The expression "alumina fragment" used in this connection refers to an Al ₂ O ₃ unit which is part of an aluminosilicate zeolite framework, that is, which is bonded by covalent bonds to other oxide fragments, such as silicon dioxide (SiO ₂ ), in the framework of aluminosilicate zeolite. The molar percentage of alumina present in the aluminosilicate zeolite is defined as the fraction of moles of Al ₂ O ₃ relative to the total number of moles of oxides constituting the aluminosilicate zeolite (before dealumination) or a modified molecular sieve (after dealumination).

Preferably, the surface of the zeolite crystallites is subjected to selective dealumination. Selective dealumination of the surface leads to a decrease in the number of acid sites on the surface of zeolite crystallites, while not changing the internal structure of zeolite crystallites.

Dealumination can be carried out by methods known in the art. Particularly useful are those methods in which dealumination occurs selectively, or in one way or another it is asserted that it occurs selectively, on the surface of crystallites of a molecular sieve. Examples of dealumination processes are described in the aforementioned document WO-A-9641849.

Preferably, dealumination is carried out by a method in which the zeolite is contacted with an aqueous solution of a fluorosilicate salt, wherein said fluorosilicate salt is represented by the formula:

(A) _{2 / b} SiF ₆

where 'A' means a metal or nonmetallic cation other than H + and having a valence of 'b'. Such processing will also be referred to as AHS processing. Examples of 'b' cations are alkyl ammonium, NH ₄ ⁺ , Mg ⁺⁺ , Li ⁺ , Na ⁺ , K ⁺ , Ba ⁺⁺ , Cd ⁺⁺ , Cu ⁺ , Ca ⁺⁺ , Cs ⁺ , Fe ⁺⁺ , Co ⁺⁺ , Pb ⁺⁺ , Mn ⁺⁺ , Rb ⁺ , Ag ⁺ , Sr ⁺⁺ , T1 ^+, and Zn ⁺⁺ . Preferably 'A' is an ammonium cation. The zeolite material can be contacted with a fluorosilicate salt at an appropriate pH of 3 to 7. Such a dealumination process is described, for example, in US Pat. No. 5,157,191. This dealumination method is called AHS processing.

The dewaxing catalyst used in accordance with the present invention is preferably obtained by first extruding the aluminosilicate zeolite with a binder, and then the extrusion product is subjected to dealumination, preferably by the AHS treatment described above. It was found that increased mechanical strength of the extrudate of the catalyst, which is prepared according to the specified sequence of stages, is achieved.

Group VIII metal of the periodic system of elements is suitably added to the catalyst extrudate containing crystallites of dealuminated aluminosilicate zeolite using known techniques such as the ion exchange method. A typical ion exchange method involves contacting a selected zeolite with a salt of a desired substitution cation. Although a wide variety of salts can be used, particular preference is given to chlorides, nitrates, and sulfates. Typical ion exchange methods are described in various in US patents, including US-A-3140249, US-A-3140251 and US-A-3140253.

In step (d), a dewaxing catalyst is used that contains a hydrogenating component of a Group VIII metal. Group VIII metal components include elements selected from noble and base metals. Accordingly, palladium, platinum, nickel and / or cobalt in sulfide, oxide and / or elemental form are particularly suitable components of Group VIII metals. It is advisable that the total amount of the metal of group VIII of the periodic system of elements will not exceed 10% by weight, based on the element and calculated on the whole weight of the carrier, and is preferably in the range from 0.1 to 5.0% by weight, more preferably from 0.2 to 3.0% by weight. If platinum as well as palladium are present, then the weight ratio of platinum to palladium can vary widely, but suitably in the range of 0.05 to 10, more suitably 0.1 to 5. Catalysts containing palladium, platinum and nickel as a hydrogenating component, are preferred. Preferably, the hydrogenating component, a Group VIII metal, is platinum or palladium, more preferably platinum.

The conditions for catalytic dewaxing in step (d) of the process of the invention are typical conditions for catalytic dewaxing. Therefore, a suitable temperature is in the range of 300 to 400 ° C., preferably in the range of 330 to 380 ° C. Suitable absolute dewaxing pressures are in the range of 80 to 240 bar abs. Preferably, the absolute dewaxing pressure is in the range of 100 to 180 bar abs, more preferably in the range of 120 to 170 bar abs. A suitable hourly average mass feed rate in step (d) is in the range of 0.4 to 7 h ^-1 , preferably in the range of 0.5 to 2.5 h ^-1 , and more preferably in the range of 0.65 to 2, 25 h ^-1 .

Stage (d) is carried out in the presence of hydrogen. Hydrogen is suitably fed to the second reaction zone in a ratio of 350 to 1,500 norms, liters per 1 kg of feed.

The dewaxed product obtained in stage (d) has a viscosity index (VI), which provides lubricating base oils with a high viscosity index. Suitably, the dewaxed product obtained in step (d) contains sulfur in an amount of less than 350 ppm by weight, preferably less than 300 ppm by weight, and the product contains nitrogen in an amount of less than 80 ppm by weight, preferably less than 60 ppm by weight. Suitably, the dewaxed product has a viscosity at 100 ° C. in the range of 10 to 17 cSt, preferably in the range of 10 to 15 cSt.

In step (e), at least a portion of the dewaxed product obtained in step (d) is subjected to a final hydrotreatment using an appropriate final hydrotreatment catalyst in the presence of a hydrogen-containing gas under the final hydrotreatment condition to obtain a heavy base oil.

Preferably, the entire dewaxed product obtained in step (d) is subjected to step (e).

Final hydrotreating is known in the art, and examples of suitable final hydrotreating steps are described, for example, in US-A-5139647, WO-A-9201657 and WO-A-9201769. Typically, final hydrotreating involves contacting a hydrocarbon feed, in this case a feed containing a dewaxed lubricating base oil, with a hydrogenation catalyst under relatively mild conditions to saturate at least a portion of the aromatic hydrocarbons that are still in the dewaxed base oil. Suitable are those catalysts that are commonly used for this purpose, that is, noble metal catalysts, such that contain Pt and / or Pd supported on an amorphous aluminosilicate carrier. In an alternative embodiment of the present invention, the hydrotreating process in step (b) uses a base metal final hydrotreating catalyst, a so-called base metal final hydrotreating catalyst, such as nickel-molybdenum on an alumina support.

The final hydrotreating conditions according to the invention include operating temperatures up to 390 ° C with a preferred range of 300 to 380 ° C, more preferably 330 to 370 ° C, an operating pressure in the range of 80 to 200 bar abs, preferably in the range of 100 to 170 bar abs., weight average weighted feed rate in the range from 0.3 to 2.5 h ^-1 , preferably in the range of 0.5-1.5 h ^-1 .

The yield of the heavy base oil in step (e) is high compared to known methods for producing base oils that use the hydrocracking and catalytic dewaxing steps. This high yield of heavy base oils can be expressed as the ratio of heavy base oil to light base oil obtained in step (e). For example, a high yield of heavy base oils may be expressed as the ratio of the base oil 500N to the base oil 150 N obtained in step (e). A 500 N base oil is a heavy Group II base oil that typically has a viscosity at 100 ° C in the range of 10.0 to 12.9 cSt, while a 150 N base oil is a light Group II base oil that typically has a viscosity at 100 ° C in the range from 4.8 to 6.8 cSt. Accordingly, the ratio of a base oil of 500 N to a base oil of 150 N obtained in step (e) is at least 1.0, preferably at least 1.5, more preferably at least 2.5, and most preferably at least least 3.0.

The indicated high yield of heavy base oils is justified by the specific sequence of technological stages (a) - (e) and the use of a special catalyst and / or combination of catalysts, and represents a major improvement compared to known methods for producing base oils, especially given the increasing demand for heavy base oils oil now.

In step (f), a heavy base oil is recovered. For example, the heavy base oil obtained in step (e) can be separated from other components of the effluent from the final hydrotreating process containing light base oils using conventional techniques, for example, by distillation under atmospheric or reduced pressure. Of these methods, distillation under reduced pressure is most expediently used, including a single evaporation in vacuum and vacuum distillation. The cut-off points of the distillate fractions are selected so that each distillate product recovered has the desired characteristics of heavy base oils for its intended use.

The corresponding heavy base oils recovered in step (f) contain sulfur in an amount of less than 300 ppm by weight, preferably less than 200 ppm by weight, and contain nitrogen in an amount of less than 80 ppm by weight, preferably less than 50 ppm by weight. Suitably, heavy base oils have a viscosity at 100 ° C. in the range of 10-15 cSt, preferably in the range of 10 to 13 cSt.

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

Examples

In step (a), the light paraffin distillate feed Basrah Light is provided.

Example 1 (according to the invention)

The feedstocks listed in Table 1 are hydrotreated over a conventional hydrotreatment catalyst — NiMo on alumina (for this example, Criterion C-424 catalyst) to produce a hydrotreated effluent (fraction 370 ° C +) containing approximately 50 ppm nitrogen and 300 ppm sulfur.

Operating conditions and the output of the main products at the hydrotreatment stage are shown in table 2.

Example 2 (comparative example)

The same feedstock (Table 1) is hydrotreated in a conventional manner to a significantly lower nitrogen and sulfur content, <5 ppm by weight, and <50 ppm by weight, respectively, to meet typical requirements for the second stage of isomerization-dewaxing with a noble metal and with a final hydrotreating catalyst, according to existing practice. In this case, a highly active NiMo / Al ₂ O ₃ type II hydrotreating catalyst is required (for example, like the Criterion DN-3100 catalyst). Operating conditions and the output of the main products at the hydrotreatment stage are shown in table 3.

In step (c), H ₂ S and NH ₃ contaminants and light products are stripped from the effluent streams obtained in Examples 1 and 2. Then, in step (d), the products obtained in step (c) are dewaxed in accordance with the present invention and in accordance with traditional dewaxing.

Example 3 (according to the invention)

The 370 ° C + fraction of Example 1 was catalytically dewaxed on a Shell base industrial dewaxing catalyst SLD-800 containing a base metal (Ni), which is specifically designed for dewaxing highly contaminated feeds.

Operating conditions and the output of the main products at the stage of catalytic dewaxing are shown in table 4.

Example 4 (comparative example)

Fractions. The 370 ° C + from Example 2 is subjected to catalytic dewaxing on a Shell noble metal (Pt) industrial dewaxing catalyst SLD-821, which is specifically designed for dewaxing highly hydrotreated raw materials for the production of base oils II and III.

The operating conditions and the yield of the main products at the stage of catalytic dewaxing are shown in table 5.

In step (e), the dewaxed product obtained in step (d) of the present invention is finally hydrotreated. Example 5 (according to the invention)

The 370 ° C + fraction from Example 3, stripped from any gases, is fed to the final hydrotreatment step, using either a base metal catalyst with a final hydrotreating (highly active NiMo / Al ₂ O ₃ type catalyst); Example 5a, or a noble metal final hydrotreating catalyst (such as the Criterion LN-5 catalyst), known as a catalyst with high hydrogenation activity and resistance to sulfur and nitrogen poisoning; example 5b.

Operating conditions and the output of the main products at the stage (e) of the final hydrotreatment are shown in table 6.

Example 6 (comparative example)

The 370 ° C + fraction from comparative example 4 stripped from any gases is fed to final hydrotreatment step (e) using a final hydrotreating catalyst (LN-5) with a noble metal from Criterion.

Operating conditions and the output of the main products at the stage (e) of the final hydrotreatment are shown in table 7.

In view of the above, it can be seen that an improvement is achieved in the method of the present invention compared to the conventional method for producing a heavy base oil.

Claims (21)

1. A method for producing a heavy base oil, comprising the steps of: (a) provide a hydrocarbon feed that contains at least 50% by weight of hydrocarbons boiling above 460 ° C., nitrogen in an amount in the range of 800 to 2500 ppm by weight and sulfur in an amount in the range of 1.5 to 4.0 mass %; (b) hydrotreating said hydrocarbon feed using a hydrotreating catalyst in the presence of a hydrogen-containing gas under hydrotreating conditions to obtain a hydrotreated product that contains nitrogen in an amount in the range of 30-80 ppm by weight and sulfur in an amount in the range of 200 to 450 ppm by weight; (c) removing at least 50% NH ₃ and H ₂ S that are present in the hydrotreated product obtained in step (b); (d) catalytic dewaxing of at least a portion of the hydrotreated product obtained in step (c) is performed using a dewaxing catalyst in the presence of a hydrogen-containing gas under catalytic dewaxing conditions to obtain a dewaxing product, said dewaxing catalyst containing a hydrogenating component of a Group VIII metal, crystallites dealuminated aluminosilicate zeolite and material of heat-resistant oxide binder with low acidity, which is essentially not soda rzhit alumina; (e) final hydrotreating at least a portion of the dewaxed product obtained in step (d) using a final hydrotreating catalyst in the presence of a hydrogen-containing gas under final hydrotreating to obtain a heavy base oil; and (f) recovering said heavy base oil. 2. The method according to p. 1, in which the hydrocarbon feed provided in stage (a) contains more than 65% by weight of hydrocarbons boiling above 460 ° C. 3. The method according to p. 1 or 2, in which the hydrocarbon feed provided in stage (a) contains at least 50% by weight of hydrocarbons having a viscosity at 100 ° C above 14 cSt. 4. The method according to p. 1 or 2, in which the ratio of the amount of nitrogen to the amount of sulfur (N / S) in the hydrotreated product obtained in stage (b) is in the range from 0.1 to 0.3. 5. The method of claim 1 or 2, wherein in step (c), NH ₃ and H ₂ S are removed from the hydrotreated product obtained in step (b) by evaporation. 6. The method of Claim. 1 or 2, wherein in step (c) removing at least 90% NH ₃ and H ₂ S, are present in the hydrotreated product obtained in step (b). 7. The method according to p. 1 or 2, in which the zeolite component in the dewaxing catalyst in stage (d) is present in an amount in the range from 10 to 50 mass. % based on the total weight of the dewaxing catalyst. 8. The method of claim 7, wherein the zeolite component is ZSM-5, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-35 or ZSM-48. 9. The method according to p. 1 or 2, in which the hydrotreating conditions in stage (b) include a temperature in the range from 250 to 480 ° C, a pressure in the range from 30 to 250 bar and an hourly average mass feed rate in the range from 0.2 to 10 hr ^-1; the dewaxing conditions in step (d) include a temperature in the range of 350 to 460 ° C., a pressure in the range of 80 to 240 bar and an hourly average mass feed rate in the range of 0.4 to 7 h ⁻¹ and final hydrotreatment conditions in the step (e) ) include a temperature in the range from 300 to 390 ° C, a pressure in the range from 80 to 200 bar and an hourly average mass feed rate in the range from 0.5-2.5 h ^-1 . 10. The method of claim 1 or 2, wherein the final hydrotreating catalyst in step (e) is a noble metal final hydrotreating catalyst. 11. The method of claim 1 or 2, wherein the final hydrotreating catalyst in step (e) is a base metal final hydrotreating catalyst. 12. The method according to p. 1 or 2, in which at the stage (c) of the hydrotreated product obtained in stage (b), hydrocarbons boiling below 370 ° C are also separated. 13. The method of claim 1 or 2, wherein the entire hydrotreated product obtained in step (b) is subjected to step (c). 14. The method of claim 1 or 2, wherein the entire hydrotreated product obtained in step (c) is subjected to step (d). 15. The method according to p. 1 or 2, in which all dewaxed product obtained in stage (d) is subjected to stage (e).