JP2012511608A - Lubricating composition - Google Patents

Abstract

(Ii) one or more additives; (ii) at least 25% by weight of a first Fischer-Tropsch derived base oil having a kinematic viscosity in the range of 6 to 10 mm ² / sec at 100 ° C .; and (iii) Selected from a second Fischer-Tropsch derived base oil having a kinematic viscosity in the range of 15 to 30 mm ² seconds at 100 ° C. at least 10% by weight, bright stock, deasphalted cylinder oil (DACO), polyisobutylene and mixtures thereof A lubricating composition comprising: a lubricating composition, wherein the lubricating composition has a TBN of at least 20 mg KOH / g and a kinematic viscosity at 100 ° C of at least 9 mm ² / sec. The lubricating composition of the present invention provides excellent lubricant-fuel compatibility.

Description

  The present invention relates to lubricating compositions, particularly for use in engines operating under sustained high load conditions such as marine diesel engines and power applications.

  Lubricating oils for use in internal combustion engines are subject to high levels of stress. Lubricants provide good lubricating properties under a wide variety of conditions, provide good wear and corrosion protection, among other properties, help keep the engine clean, and against heat and oxidation It is essential that it be stable and heat should be removed from the engine.

  The lubricating oils used in marine diesel engines are subject to particularly high levels of stress due to the fact that marine engines usually operate continuously under near full load conditions for long periods of time, often at remote locations. Furthermore, the lubricating oil is expected to have a long life because there is often little or no opportunity to replace the lubricating oil in the marine engine.

  It will be appreciated in the art that the term “marine” does not limit such engines to those used for surface vessels. That is, the term further includes engines used for power generation applications. Such high performance, low fuel consumption low speed and medium speed marine and stationary diesel engines operate at high pressure, high temperature and long stroke.

  All engine lubricants are at risk of contamination by fuel components, and the resulting degradation in lubrication properties is indicated by the lubricant. However, as mentioned above, marine engines are expected to operate continuously over a long period of time, usually with little opportunity to respond quickly to lubricant failures, and are therefore intended for use in marine engines. Of particular importance is that the lubricants of this type are highly compatible with the fuel used to power the engine.

Surprisingly, a Fischer-Tropsch derived base oil having a kinematic viscosity in the range of 6 to 10 mm ² / sec at 100 ° C. is now included in the lubricating composition along with a specified thickener and one or more additives. It has been found that a significant improvement in lubricant-fuel compatibility is observed.

According to the invention, a lubricating composition comprising:
(I) one or more additives;
(Ii) at least 25% by weight of a first Fischer-Tropsch derived base oil having a kinematic viscosity in the range of 6 to 10 mm ² / sec at 100 ° C .; and (iii) at least 10% by weight at 100 ° C. A thickener selected from a second Fischer-Tropsch derived base oil having a kinematic viscosity in the range of 15 to 30 mm ² sec- ¹ , bright stock, deasphalted cylinder oil (DACO), polyisobutylene and mixtures thereof;
A lubricating composition is provided wherein the lubricating composition has a TBN of at least 20 and a kinematic viscosity at 100 ° C. of at least 9 mm ² / sec.

  The lubricating composition has excellent lubricating properties and provides improved lubricant-fuel compatibility.

  Accordingly, another aspect of the present invention provides a lubricating composition, wherein the composition comprises 50 ml at a lubricant: fuel weight ratio of 60:40 or greater in a lubricant-fuel compatibility test method as described herein below. Provides an oil phase that exceeds.

In accordance with yet another aspect of the present invention, a Fischer-Tropsch having a kinematic viscosity in the lubricating composition at 100 ° C. in the range of 6 to 10 mm ² / sec to provide improved lubricant-fuel compatibility. Use of a derived base oil is provided.

  According to yet another aspect of the present invention, there is provided the use of a lubricating composition as described herein below for lubricating a medium speed four stroke engine, preferably a marine engine.

  The term “lubricant-fuel compatibility” as used herein means the ability of a mixture of lubricant and fuel to remain in a single liquid phase. As used herein, the term “improved lubricant-fuel compatibility” refers to an increase in lubricant and fuel (from a lubricant and fuel mixture) at a given lubricant: fuel ratio. ) Means in a single liquid phase. In particular, the term “improved lubricant-fuel compatibility” as used herein, preferably the lubricating composition of the present invention is 60:40 in the lubricant-fuel compatibility test method described later herein. This means providing an oil phase in excess of 50 ml at the above lubricant: fuel weight ratio.

The first essential component in the compositions herein is a movement at 100 ° C. in the range of 6 to 10 mm ² / sec, preferably in the range of 7 to 9 mm ² / sec, especially about 8 mm ² / sec. It is a Fischer-Tropsch derived base oil having a viscosity (hereinafter referred to as a Fischer-Tropsch derived light base oil).

  The term “derived from Fischer-Tropsch” as used herein means that the substance is a synthetic product of a Fischer-Tropsch enrichment process or is derived from a synthetic product. Fischer-Tropsch derived products may also be referred to as “GTL (gas-to-liquid)” products.

Fischer-Tropsch concentration method:
n (CO + 2H ₂ ) = (— CH ₂ —) _n + nH ₂ O + heat is typically in the presence of a suitable catalyst, typically at high temperature (eg 125 to 300 ° C., preferably 175 to 250 ° C.) and / or high pressure (eg 5 To 100 bar, preferably 12 to 50 bar), which converts carbon monoxide and hydrogen to longer chains, usually paraffinic hydrocarbons. Hydrogen: carbon monoxide ratios other than 2: 1 can be used if desired.

  Carbon monoxide and hydrogen itself can be derived from organic or inorganic, natural or synthetic sources, typically from either natural gas or organic derived methane. In general, gases that are converted to liquid fuel components using the Fischer-Tropsch process are natural gas (methane), LPG (eg propane or butane), “condensate” such as ethane, syngas (CO / hydrogen) and Gaseous products derived from coal, biomass and other hydrocarbons can be included.

  The Fischer-Tropsch process can be used to prepare a series of hydrocarbon fuels including LPG, naphtha, kerosene and gas oil fractions. Of these, gas oils have been used as and in automotive diesel fuel compositions, typically in blends with petroleum-derived gas oils. Heavier fractions can be obtained after hydroprocessing and vacuum distillation, and a series of base oils have various distillation characteristics and viscosities that are useful as lubricating base oil stocks.

  The hydrocarbon product can be obtained directly from a Fischer-Tropsch reaction or indirectly, for example, by fractional distillation of a Fischer-Tropsch synthesis product or from a hydrotreated Fischer-Tropsch synthesis product. Hydroprocessing can include hydrocracking to adjust the boiling range and / or hydroisomerization that can improve cold flow properties by increasing the proportion of branched paraffins. Other synthetic post-treatments such as polymerization, alkylation, distillation, pyrolysis-decarboxylation, isomerization and hydrogen reforming can be used to modify the properties of the Fischer-Tropsch concentrated product.

  Typical catalysts for the Fischer-Tropsch synthesis of paraffinic hydrocarbons include Group VIII metals of the periodic table, particularly ruthenium, iron, cobalt or nickel, as catalytically active components. Suitable such catalysts are described, for example, in EP-A-0583836 (pages 3 and 4).

Examples of the method according to the Fischer-Tropsch is, "The Shell Middle Distillate Synthesis Process", van der Burgt et al, paper delivered at the 5 th Synfuels Worldwide Symposium, Washington DC, SMDS , which is described in the November 1985 (Shell middle distillates See also the November 1989 publication of the same title by Shell International Petroleum Company Ltd, London, UK. The method (sometimes also referred to as shell “gas-to-liquid” or “GTL” technology) converts synthetic gas from natural gas (mainly methane) to heavy long-chain hydrocarbon (paraffin) wax, Middle chain range products are produced by hydroconverting and fractionating long chain hydrocarbon waxes to produce gas oils that can be used in liquid transportation fuels, such as diesel fuel compositions. Base oils, including heavy base oils, can also be produced by such methods. One type of SMDS process that utilizes a fixed bed reactor is currently used in Bintulu, Malaysia, and this gas oil product is blended with petroleum-derived gas oil in commercial automotive fuels.

  Because of the Fischer-Tropsch process, the Fischer-Tropsch derived base oil has essentially no sulfur and nitrogen or undetectable levels of sulfur and nitrogen. Compounds containing these heteroatoms tend to act as poisons for Fischer-Tropsch catalysts and are therefore removed from the synthesis gas feed. This can provide additional benefits to the lubricant composition according to the present invention.

  Furthermore, the Fischer-Tropsch process produces no or essentially no aromatic component, as is normally done. The aromatic content of the Fischer-Tropsch derived base oil component, suitably determined by ASTM D-4629, is typically less than 1% by weight, preferably 0.5% by weight on a molecular basis (as opposed to an atomic basis) and More preferably it will be less than 0.1% by weight.

  Generally speaking, Fischer-Tropsch derived hydrocarbon products have relatively low levels of polar components, especially polar surfactants, compared to, for example, petroleum derived hydrocarbons. This can contribute to the improvement of defoaming and turbidity removal performance. Such polar components can include, for example, oxygen additives and sulfur and nitrogen containing compounds. A low level of sulfur in Fischer-Tropsch derived hydrocarbons generally indicates that both oxygenates and nitrogen-containing compounds are low because all are removed by the same processing method. .

  The Fischer-Tropsch derived light base oil is present in the lubricating compositions herein at a level of at least 25%, preferably at least 30%, more preferably 35% by weight of the lubricating composition.

  The Fischer-Tropsch derived light base oil is preferably present in the lubricating composition herein up to 70%, more preferably up to 60%, even more preferably up to 50% by weight of the lubricating composition. Exists at level.

  Suitable Fischer-Tropsch derived light base oils that can be conveniently used in the lubricating compositions of the present invention include, for example, EP0776959, EP0668342, WO97 / 21788, WO00 / 15736, WO00 / 14188, WO00 / 14187, WO00 / 14183, Including those described in WO00 / 14179, WO00 / 08115, WO99 / 41332, EP1029029, WO01 / 18156 and WO01 / 57166.

  A particularly preferred light base oil derived from Fischer-Tropsch is “GTL 8”.

The second essential component of the lubricating composition herein is a second Fischer-Tropsch derived base oil having a kinematic viscosity in the range of 15 to 30 mm ² / sec ⁻¹ at 100 ° C., bright stock, deasphalted A thickener selected from cylinder oil (DACO), polyisobutylene and mixtures thereof.

  The thickener is at least 5% by weight of the composition, preferably at least 10%, more preferably at least 20%, even more preferably at least 25%, especially at least 30%, and more particularly at least 35%. Exists at the level of.

  As used herein, the thickener is preferably present at a level of up to 60%, more preferably up to 50%, and especially up to 40% by weight of the composition.

Preferred thickeners for use herein have a kinematic viscosity at 100 ° C. in the range of 15 to 30 mm ² / sec, preferably in the range of 18 to 27 mm ² / sec, and the first Fischer-Tropsch This is a second Fischer-Tropsch-derived paraffinic base oil that is different from the derived base oil (hereinafter referred to as “Fischer-Tropsch-derived heavy base oil”). In one embodiment of the invention, the Fischer-Tropsch derived heavy base oil has a viscosity in the range of 18 to 22 mm ² / sec at 100 ° C. In another embodiment of the invention, the Fischer-Tropsch derived heavy base oil has a kinematic viscosity in the range of 24 to 27 mm ² / sec at 100 ° C.

  As described above, the Fischer-Tropsch process can be used to prepare a series of hydrocarbon fuels including LPG, naphtha, kerosene and gas oil fractions. Of these, gas oils have been used as and in automotive diesel fuel compositions, typically in blends with petroleum-derived gas oils. Heavier fractions can be obtained after hydroprocessing and vacuum distillation, with a range of base oils having different distillation characteristics and viscosities that are useful as lubricating base oil stocks. The so-called “bottom product” that remains after recovering the lubricating base oil cut from the higher molecular weight, vacuum column is usually recycled to the hydrocracking unit to be converted to a lower molecular weight product, resulting in a lubricating base oil. Often considered unsuitable for use as such.

  However, an appropriately treated Fischer-Tropsch bottom base oil (hereinafter referred to as “Fischer-Tropsch derived heavy base oil”) is a Fischer-Tropsch lighter from the viewpoint of improving lubricant-fuel compatibility. It has been found that it can be advantageous in lubricating compositions with base oils.

  When the thickener is a Fischer-Tropsch derived heavy base oil, the thickener is preferably at a level of at least 25%, more preferably at least 30%, even more preferably at least 35% by weight of the composition. Exists. When the thickener is a Fischer-Tropsch derived heavy base oil, the thickener is preferably at most 60%, more preferably at most 50%, and even more preferably at most by weight of the lubricating composition. It exists at a level of 40%.

  In the context of the present invention, the Fischer-Tropsch derived paraffinic heavy base oil is preferably Fischer-Tropsch “bottom” (ie high), either directly or indirectly after one or more downstream processing steps. Boiling point) is a base oil derived from the product. Fischer-Tropsch bottom product is the hydrocarbon product recovered from a fractionation column, usually a vacuum column, after fractional distillation of the Fischer-Tropsch derived feed stream.

  More preferably, the paraffinic base oil is prepared by hydroisomerization of paraffin wax as prepared in a Fischer-Tropsch synthesis step and dewaxing of the residue separated from the hydroisomerization process effluent. . Examples of such methods suitable for the preparation of paraffinic base oils are described in WO-A-2004 / 007647, US-A-US2004 / 0065588, WO-A-2004 / 033595 and WO-A-02070627. And these publications are incorporated herein by reference.

The relatively heavy feed to the hydroisomerization step is suitably at least 0.2, preferably at least 0.4 and more preferably at least 0.55 compounds having at least 60 carbon atoms and Having a weight ratio of compounds having at least 30 carbon atoms. Furthermore, the feedstock has at least 30% by weight, preferably at least 50% by weight and more preferably at least 55% by weight of compounds having at least 30 carbon atoms. Such feedstock preferably comprises a Fischer-Tropsch product, which in turn is at least 0.925, preferably at least 0.935, more preferably at least 0.945, and even more. Preferably it comprises a C ₂₀ + fraction having an ASF-alpha value (Anderson-Schulz-Flory Chain Growth Factor) of at least 0.955. The initial boiling point of the feedstock is preferably less than 200 ° C. Preferably, no compound of 4 carbon atoms or less and any compound having a boiling point within this range are present in the feedstock. The feed may also include process recycles and / or substandard base oil fractions such as those obtained after dewaxing.

  A suitable Fischer-Tropsch synthesis method that can produce a relatively heavy Fischer-Tropsch product is described, for example, in WO-A-9934917.

The method generally comprises a Fischer-Tropsch synthesis to obtain a Fischer-Tropsch wax, a hydroisomerization step and a residual pour point depressing step,
(A) hydrocracking / hydroisomerizing Fischer-Tropsch wax;
(B) separating the distillation residue from the product of step (a); and (c) dewaxing the distillation residue to obtain a paraffinic base oil; and optionally (d) removing the light ends. And re-distilling the paraffinic base oil to obtain a residual paraffinic base oil having the desired viscosity.

  The hydrogen conversion / hydroisomerization reaction of step (a) is preferably carried out in the presence of hydrogen and a catalyst, which can be selected from those known to those skilled in the art as suitable for this reaction, This will be explained in more detail below. The catalyst can in principle be any catalyst known in the art to be suitable for the isomerization of paraffinic molecules. In general, suitable hydrogen conversion / hydroisomerization catalysts are refractory oxide supports such as amorphous silica-alumina (ASA), alumina, fluorinated alumina, molecular sieves (zeolite) or mixtures of two or more thereof. A catalyst comprising a supported hydrogenation component. One preferred catalyst utilized in the hydrogen conversion / hydroisomerization step according to the present invention is a hydrogen conversion / hydroisomerization catalyst comprising platinum and / or palladium as a hydrogenation component. A highly preferred hydrogen conversion / hydroisomerization catalyst comprises platinum and palladium supported on an amorphous silica-alumina (ASA) support. Platinum and / or palladium is preferably calculated as an element and in an amount of 0.1 to 5.0% by weight, more preferably 0.2 to 2.0% by weight, based on the total weight of the support Exists. When both are present, the ratio of platinum to palladium can vary within wide limits, but preferably in the range of 0.05 to 10, more preferably 0.1 to 5. Examples of suitable noble metals on ASA catalysts are disclosed, for example, in WO-A-9410264 and EP-A-0582347. Other suitable noble metal based catalysts, such as platinum-supported fluorinated alumina supports, are disclosed, for example, in US-A-5059299 and WO-A-9220759.

  A second type of suitable hydrogen conversion / hydroisomerization catalyst comprises at least one Group VIB metal, preferably tungsten and / or molybdenum, and at least one Group VIII non-noble metal, preferably nickel, as the hydrogenation component. And / or a catalyst containing cobalt. Either metal can be present as an oxide, sulfide, or a combination thereof. The Group VIB metal is preferably calculated as an element and is present in an amount of 1 to 35 wt%, more preferably 5 to 30 wt%, based on the total weight of the support. The Group VIII non-noble metal is suitably calculated as an element and is present in an amount of 1 to 25% by weight, preferably 2 to 15% by weight, based on the total weight of the support. This type of hydrogen conversion catalyst has been found to be particularly suitable and is a catalyst comprising nickel and tungsten supported on fluorinated alumina.

  The above non-noble metal based catalyst is preferably used in this sulfide form. Some sulfur must be present in the feed to maintain the sulfided form of the catalyst during use. Preferably at least 10 mg / kg and more preferably 50 to 150 mg / kg sulfur is present in the feed.

Preferred catalysts that can be used in non-sulfided form include Group VIII non-noble metals such as iron, nickel in combination with Group IB metals such as copper, supported on an acidic support. Copper is preferably present to inhibit hydrogenolysis of paraffin to methane. The catalyst preferably has a pore volume in the range of 0.35 to 1.10 ml / g as determined by water absorption, preferably a surface area of 200 to 500 m ² / g as determined by BET nitrogen adsorption. And a bulk density of 0.4 to 1.0 g / ml. The catalyst support preferably consists of amorphous silica-alumina, which can be present in a wide range of 5 to 96% by weight, preferably 20 to 85% by weight. The silica content as SiO ₂ is preferably 15 to 80% by weight. The support may also contain small amounts, eg 20 to 30% by weight, of binders such as alumina, silica, Group IVA metal oxides and various types of clays, magnesia, etc., preferably alumina or silica.

  The preparation of amorphous silica-alumina microspheres is described in Ryland, Lloyd B. et al. , Tamale, M .; W. , And Wilson, J .; N. , Cracking Catalysts, Catalysis: volume VII, Ed. Paul H. Emmet, Reinhold Publishing Corporation, New York, 1960, pp. 5-9.

The catalyst is prepared by co-impregnating the metal from the solution onto the support, drying at 100 to 150 ° C., and calcining in air at 200 to 550 ° C. The Group VIII metal is present in an amount up to about 15% by weight, preferably from 1 to 12% by weight, while the Group IB metal is present in a lesser amount, for example 1: 2 relative to the Group VIII metal. To 1:20 by weight. Representative catalysts are shown below:
Ni, weight% 2.5 to 3.5
Cu, wt% 0.25 to 0.35
Al ₂ O ₃ —SiO ₂ wt% 65 to 75
Al ₂ O ₃ (binder) wt% 25-30
Surface area from 290 to 325 m ² / g
Pore volume (Hg) 0.35 to 0.45 ml / g
Bulk density 0.58 to 0.68 g / ml
Another class of suitable hydroconversion / hydroisomerization catalysts are based on zeolitic materials, preferably comprising at least one Group VIII metal component, preferably Pt and / or Pd, as a hydrogenation component It is. Suitable zeolitic and other aluminosilicate materials here are zeolite beta, zeolite Y, ultrastable Y, ZSM-5, ZSM-12, ZSM-22, ZSM-23, ZSM-48, MCM-68, ZSM-35, SSZ-32, ferrierite, mordenite and silica-aluminophosphates such as SAPO-11 and SAPO-31. Examples of suitable hydroisomerization / hydroisomerization catalysts are described, for example, in WO-A-9201657. Combinations of these catalysts are also possible. A very suitable hydroconversion / hydroisomerization process is the first step in which a zeolite beta-based catalyst is used and ZSM-5, ZSM-12, ZSM-22, ZSM-23, ZSM-48, MCM-68, A process comprising a second step in which a ZSM-35, SSZ-32, ferrierite, mordenite based catalyst is used. Of the latter group, ZSM-23, ZSM-22 and ZSM-48 are preferred. Examples of such methods are described in US-A-2004 / 0065581 and US-A-2004 / 0065588. In the process of US-A-2004 / 0065588, steps (a) and (c) as intended in the context of the present description are carried out using the same ZSM-48 based catalyst.

  The Fischer-Tropsch product is first subjected to a first hydroisomerization step using an amorphous catalyst comprising a silica-alumina support as described above, followed by a second hydroisomerization using a catalyst comprising molecular sieves. Combinations that undergo a crystallization step have also been recognized as a preferred method of preparing the base oils used in the present invention. Further preferred first and second hydroisomerization steps are carried out in series flow.

  In step (a), the feedstock is contacted with oxygen in the presence of a catalyst at an elevated temperature and pressure. The temperature will typically range from 175 to 380 ° C, preferably above 250 ° C, and more preferably from 300 to 370 ° C. The pressure will typically be in the range of 10 to 250 bar, and preferably 20 to 80 bar. Hydrogen can be supplied at a gas hourly space velocity of 100 to 10,000 Nl / l / hour, preferably 500 to 5000 Nl / l / hour. The hydrocarbon feed may be fed at a weight space velocity of 0.1 to 5 kg / l / hour, preferably greater than 0.5 kg / l / hour, and more preferably less than 2 kg / l / hour. The ratio of hydrogen to hydrocarbon feedstock can range from 100 to 5000 Nl / kg, preferably 250 to 2500 Nl / kg.

  The conversion of step (a) is defined as the percentage of feedstock boiling above 370 ° C. that reacts per pass to the fraction boiling below 370 ° C., preferably at least 20% by weight, preferably at least 25% by weight, but preferably 80% by weight or less, more preferably 65% by weight or less. The feedstock as used in the above definition is the total hydrocarbon feedstock fed to step (a) and thus any recycle of any of the high boiling fractions obtainable in step (b). It is also a circulation.

  In step (b), the residue is isolated from the product of step (a). By residue herein is meant that the compound with the highest boiling point present in the discharge of step (a) is part of the residue. The distillation can be carried out at atmospheric pressure as illustrated in WO-A-02 / 070627 or at a lower pressure as illustrated in WO-A-2004 / 007647.

  Step (c) can be performed by solvent or catalytic dewaxing. Solvent dewaxing is advantageous because a non-cloudy paraffinic oil is then obtained, for example as described in WO-A-0246333. A cloudless base oil is defined as a composition having a cloud point of less than 15 ° C. A cloudy paraffinic base oil has a cloud point of 15 ° C. or higher. Catalytic dewaxing can result in a hazy paraffinic base oil, as illustrated in WO-A-2004 / 033595 and 2004/0065588. However, catalytic dewaxing is preferred over solvent dewaxing because this procedure is simpler. Accordingly, methods have been developed to remove haze from cloudy paraffinic base oils, such as obtained by catalytic dewaxing. Examples of said methods are US-A-6051129, US-A-2003 / 0075477 and US-A-6468417. Applicants have now found that preparing a blend oil using a cloudy paraffinic base oil as prepared by catalytic dewaxing results in a clear, light product. Therefore, a very interesting application has been found for such hazy paraffinic base oils obtained from Fischer ™ Tropsch wax.

  Dewaxing is preferably done by catalytic dewaxing. Catalytic dewaxing is known to those skilled in the art and is preferably carried out in the presence of a suitable heterogeneous catalyst comprising hydrogen and molecular sieves and optionally in combination with a metal having a hydrogenating function, for example a Group VIII metal. Done. Molecular sieves, and more preferably intermediate pore size zeolites, have shown good catalytic ability to lower the pour point of the base oil precursor fraction under catalytic dewaxing conditions. Preferably, the intermediate pore size zeolite has a pore size of 0.35 to 0.8 nm. Suitable intermediate pore size zeolites are mordenite, ZSM-5, ZSM-12, ZSM-22, ZSM-23, SSZ-32, ZSM-35 and ZSM-48. Another preferred group of molecular sieves are silica-alumina phosphate (SAPO) materials, of which SAPO-11 is most preferred as described, for example, in US-A-4859311. ZSM-5 can optionally be used in this HZSM-5 form when none of the Group VIII metal is present. Other molecular sieves are preferably used in combination with the added Group VIII metal. Preferred Group VIII metals are nickel, cobalt, platinum and palladium. Examples of possible combinations are Ni / ZSM-5, Pt / ZSM-23, Pd / ZSM-23, Pt / ZSM-48 and Pt / SAPO-11. Further details and examples of suitable molecular sieves and dewaxing conditions are described, for example, in WO-A-9718278, US-A-5053373, US-A-5252527, US-A-45744043, US-A-5157191, WO-A. -0029511, EP-A-832171.

  Catalytic dewaxing conditions are known in the art, typically an operating temperature of 200 to 500 ° C., preferably in the range of 250 to 400 ° C., a hydrogen pressure of 10 to 200 bar, preferably in the range of 40 to 70 bar. 0.1 to 10 kg (kg / l / hour) per hour per liter of catalyst, preferably 0.2 to 5 kg / l / hour, more preferably 0.5 to 3 kg / l / hour It includes a range of weight space velocity (WHSV) and a hydrogen to oil ratio in the range of 100 to 2,000 liters of hydrogen per liter of oil.

  The desired paraffinic base oil having the required viscosity can be obtained directly from the discharge of step (c). If necessary, any lower boiling compounds can be removed by distillation in step (d) in order to meet the viscosity requirements as defined above.

  A preferred method of preparing a Fischer-Tropsch derived paraffinic heavy base oil for use in the present invention is described in US-A-7354508, the disclosure of which is hereby incorporated by reference.

  Another suitable thickener for use herein is deasphalted cylinder oil (DACO). Deasphalted cylinder oil can be prepared by deasphalting mineral-derived vacuum residues to obtain deasphalted oil, solvent extraction of deasphalted oil, and deasphalted cylinder oil (DACO) extract. The deasphalted cylinder oil (DACO) extract can be subjected to a solvent dewaxing step before being used in the present invention. Preferably, the deasphalted cylinder oil extract is used as obtained in the solvent extraction process step without the deasphalted cylinder oil being subjected to a dewaxing step. Further details regarding methods of preparing deasphalted cylinder oil are found in EP-A-1752514, the disclosure of which is hereby incorporated by reference, including the references referenced in EP-A-1752514. .

  When present in the lubricating composition of the present invention, the deasphalted cylinder oil is preferably 0.1% to 20%, more preferably 1% to 10%, and especially 3% to 8%. Present at the% level.

The kinematic viscosity at 100 ° C. of the deasphalted cylinder oil is preferably at least 40 mm ² / sec, more preferably at least 48 mm ² / sec. The pour point of deasphalted cylinder oil is preferably less than 50 ° C, more preferably less than 27 ° C and most preferably less than 21 ° C.

  Other suitable thickeners for use in the lubricating compositions herein are petroleum derived bright stock base oils and polyisobutenes herein.

  Bright stock oils operate with residual fuels in lubricating oil compositions, especially for marine and stationary low-speed crosshead diesel engines that burn residual fuel with a sulfur content up to 4.0% by weight, and in industrial and marine applications Used as a base oil in lubricating oil compositions for trunk piston medium speed engines.

  There are no particular restrictions on the type of bright stock oil that can be used herein. Brightstock base oils suitable for use herein include those available under the name “HVI” from Royal Dutch / Shell Group of Companies, such as HVI650 (commercially available under the trade name Catenex S579). .

  When the thickener is a bright stock base oil, the bright stock base oil is typically present at a level of about 5% to about 50%, preferably about 10% to about 30% by weight of the composition.

  Polyisobutene is also suitable for use as a thickener in the lubricating compositions herein. Suitable polyisobutenes for use herein include those disclosed in WO 2006/064138, the teachings of which are incorporated herein by reference.

  The lubricating composition of the present invention may also contain additional base oil components in addition to the base oil components already described above. Any conventional base oil suitable for use in a lubricating composition can be used herein.

  Base oils suitable for use in the lubricating oil composition of the present invention include Group I, Group II or Group III base oils, polyalphaolefins, Fischer-Tropsch derived base oils (other than those already mentioned above) and mixtures thereof including.

  In the present invention, “Group I” base oil, “Group II” base oil, and “Group III” base oil are lubricant base oils in accordance with the definitions of American Petroleum Institute (API) categories I, II and III. Means. Such API categories are defined in API Publication 1509, 15th Edition, Appendix E, April 2002.

  Synthetic oils include hydrocarbon oils such as olefin oligomers (PAO), dibasic acid esters, polyol esters, and dewaxing-like raffinates. A synthetic hydrocarbon base oil sold by the Shell Group under the name “XHVI” ™ may be conveniently used.

  In one embodiment of the present invention, the base oil is a mineral-based base oil sold under the names “HVI” or “MVIN” by the Royal Dutch / Shell Group of Companies. A particularly preferred example of such a base oil is HVI 160S (commercially available under the trade name Catenex S542).

  Despite the fact that mixtures of the above types of base oils can be used in the lubricating composition of the present invention, in a preferred embodiment of the present invention, the base oil is a Fischer-Tropsch combined with a Fischer-Tropsch derived heavy base oil. Consists only of derived light base oil.

The lubricating composition of the present invention is formulated to have a kinematic viscosity at 100 ° C. of at least 9 mm ² / sec, preferably at least 10 mm ² / sec, and even more preferably at least 12.5 mm ² / sec. The lubricating composition of the present invention preferably has a kinematic viscosity at 100 ° C. of at most 20 mm ² / sec, preferably at most 18 mm ² / sec, more preferably at most 16.3 mm ² / sec. Prepared.

  The lubricating composition herein is particularly suitable for use as a lubricant in marine diesel engines.

  Diesel engines can generally be classified as low speed, medium speed or high speed engines, which are used in deep draft and industrial applications.

  A low-speed diesel engine is typically a direct-coupled self-reversing two-stroke engine that operates in the range of about 57 to 250 rpm and typically operates with residual fuel. These engines are crosshead structures with diaphragms and stuffing boxes that isolate the power cylinder from the crankcase to prevent combustion products from entering the crankcase and mixing with crankcase oil.

  Medium speed engines typically operate in the range of 250 to about 1100 rpm and can operate in four stroke or two stroke cycles. These engines are trunk piston designs, many of which can operate with residual fuel containing more than 1.5% sulfur. These engines can also operate with distilled fuel containing little or no residue. In offshore vessels, these engines can be used for propulsion applications, auxiliary applications, or both.

  Low and medium speed marine diesel engines are also widely used in power plant operations. The present invention can also be used for such applications.

  Each type of diesel engine uses lubricating oil to lubricate a valve train mechanism including piston rings, cylinder liners, crankshaft and connecting rod bearings, cams and valve lifters, among other movable members. Lubricants prevent component wear, remove heat, neutralize and disperse combustion products, prevent rust and corrosion, and prevent sludge formation or deposition.

  In low speed marine crosshead diesel engines, the cylinder and crankcase are individually lubricated, and cylinder lubrication is provided on a once-through basis by an injection device that feeds cylinder oil to a lubricator located around the cylinder liner. This is known as a “total loss” lubrication system. Cylinder oils are typically formulated to provide good oxidation and thermal stability, water demulsibility, corrosion protection and good defoaming performance. There are also alkaline detergent additives to neutralize the acid formed during the combustion process. The use of suitable additives can also provide dispersion, antioxidant, antifoam, antiwear and ultra high pressure (EP) performance.

  Preferably, the lubricating composition of the present invention comprises a dispersant, a cleaning agent, an antiwear agent, a lubricant, a thickener, a metal passivator, an acid sequestering agent, a pour point depressant, an anticorrosive, It includes one or more additives selected from foams, seal fixatives or seal compatibilizers and antioxidants.

  Preferably, all of the additives listed above are present in the lubricating oil composition of the present invention. Examples of such additives are described, for example, in US-B-6596673, the publication of which is hereby incorporated by reference.

  Detergents that can be conveniently used in the lubricating oil compositions of the present invention include one or more detergents selected from phenate detergents, salicylate detergents and sulfonate detergents. Alkali metal and alkaline earth metal salicylates, phenates and sulfonate detergents are preferred in the lubricating oil composition of the present invention. Calcium and magnesium salicylates, phenates and sulfonates are particularly preferred cleaning agents therein.

  The detergent used in the lubricating oil composition of the present invention is each independently a TBN (total base of 30 to 350 mg KOH / g, preferably about 70 mg KOH / g as measured by ISO 3771. Preferably present in a total amount ranging from 0.5 to 18% by weight, based on the total weight of the lubricating oil composition.

  The lubricating composition herein is preferably at least 20 mg KOH / g, more preferably at least 25 mg KOH / g, even more preferably at least 30 mg KOH / g, and especially as measured by ISO 3771 It has a total base number (TBN) of at least 40 mg KOH / g. The lubricating composition herein preferably has a total base number (TBN) of at most 60 mg KOH / g, more preferably at most 50 mg KOH / g.

  Antioxidants that may be conveniently used in the lubricating oil composition of the present invention are one or more antioxidants selected from the group of amine-based antioxidants and / or phenolic antioxidants. The antioxidant may generally be present in a total amount ranging from 0 to 2% by weight, based on the total weight of the lubricating oil composition.

  Examples of amine antioxidants that may be conveniently used include alkylated diphenylamine, phenyl-α-naphthylamine, phenyl-β-naphthylamine and alkylated-α-naphthylamine.

  Preferred amine-based antioxidants are dialkyldiphenylamines such as p, p'-dioctyl-diphenylamine, p, p'-di-α-methylbenzyl-diphenylamine and Np-butylphenyl-Np'-octylphenylamine. Monoalkyl diphenylamines, such as mono-t-butyldiphenylamine and mono-octyldiphenylamine, bis (dialkylphenyl) amines, such as di- (2,4-diethylphenyl) amine and di (2-ethyl-4-nonylphenyl) amine Alkylphenyl-1-naphthylamines such as octylphenyl-1-naphthylamine and nt-dodecylphenyl-1-naphthylamine, 1-naphthylamine, arylnaphthylamines such as phenyl-1-naphthylamine, Nyl-2-naphthylamine, N-hexylphenyl-2-naphthylamine and N-octylphenyl-2-naphthylamine, phenylenediamines such as N, N′-diisopropyl-p-phenylenediamine and N, N′-diphenyl-p-phenylene Diamines, and phenothiazines such as phenothiazine and 3,7-dioctylphenothiazine.

  Preferred amine-based antioxidants are the following trade names: “Sonoflex OD-3” (from Seiko Kagaku Co.), “Irganox L-57” (from Ciba Specialty Chemicals Co.), and phenothiazine (from Hodogaya K.). Including those available at

Examples of phenolic antioxidants that may be conveniently used include C ₇ -C ₉ branched alkyl esters of 3,5-bis (1,1-dimethyl-ethyl) -4-hydroxy-benzenepropionic acid, 2- t-butylphenol, 2-t-butyl-4-methylphenol, 2-t-butyl-5-methylphenol, 2,4-di-t-butylphenol, 2,4-dimethyl-6-t-butylphenol, 2- t-butyl-4-methoxyphenol, 3-t-butyl-4-methoxyphenol, 2,5-di-t-butylhydroquinone, 2,6-di-t-butyl-4-alkylphenol, for example 2,6- Di-t-butylphenol, 2,6-di-t-butyl-4-methylphenol and 2,6-di-t-butyl-4-ethylphenol, 2,6-di-t-butyl Ru-4-alkoxyphenols such as 2,6-di-t-butyl-4-methoxyphenol and 2,6-di-t-butyl-4-ethoxyphenol, 3,5-di-t-butyl-4- Hydroxybenzyl mercaptooctyl acetate, alkyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, for example n-octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) ) Propionate, n-butyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate and 2'-ethylhexyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) Propionate, 2,6-di-t-butyl-α-dimethylamino-p-cresol, 2,2′-methylene-bis (4-alkyl-6- -Butylphenol), such as 2,2′-methylenebis (4-methyl-6-tert-butylphenol, and 2,2-methylenebis (4-ethyl-6-tert-butylphenol), bisphenols such as 4,4′-butylidenebis ( 3-methyl-6-tert-butylphenol, 4,4′-methylenebis (2,6-di-tert-butylphenol), 4,4′-bis (2,6-di-tert-butylphenol), 2,2- (Di-p-hydroxyphenyl) propane, 2,2-bis (3,5-di-t-butyl-4-hydroxyphenyl) propane, 4,4′-cyclohexylidenebis (2,6-t-butylphenol) ), Hexamethylene glycol bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], triethylene glycol bis [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate], 2,2′-thio- [diethyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) Propionate], 3,9-bis {1,1-dimethyl-2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl} 2,4,8,10-tetra Oxaspiro [5,5] undecane, 4,4′-thiobis (3-methyl-6-tert-butylphenol) and 2,2′-thiobis (4,6-di-tert-butylresorcinol), polyphenols such as tetrakis [Methylene-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenol) Nyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, bis- [3,3′-bis (4′- Hydroxy-3'-t-butylphenyl) butyric acid] glycol ester, 2- (3 ', 5'-di-t-butyl-4-hydroxyphenyl) methyl-4- (2 ", 4" -di-t- Butyl-3 "-hydroxyphenyl) methyl-6-t-butylphenol and 2,6-bis (2'-hydroxy-3'-t-butyl-5'-methylbenzyl) -4-methylphenol, and pt -Butylphenol-formaldehyde condensate and pt-butylphenol-acetaldehyde condensate.

  Preferred phenolic antioxidants are the following trade names: “Irganox L-135” (from Ciba Specialty Chemicals Co.), “Antage DBH” (from Kawaguchi Chikaku Co.), “Yoshinox SS” (Yoshik SS. ), “Antage W-400” (from Kawaguchi Kagaku Co.), “Antage W-500” (from Kawaguchi Kagaku Co.), “Antage W-300” (Kawaguchi Kaga on H, A From Japan Co.), Shell Japan Co. Bisphenol A, “Irganox L109” (from Ciba Specialty Chemicals Co.), “Tominox 917” (from Yoshitomi Seigaku Co.), “Irganox L115” (CibaSip). Sumitomo Kagaku), “Antage RC” (from Kawaguchi Kagaku Co.), “Irganox L101” (from Ciba Specialty Chemicals Co.), “Yoshinos 930o”. .Than) Including those available at

  In a preferred embodiment, the lubricating oil composition of the present invention may comprise one or more zinc dithiophosphates as antiwear additives, wherein the or each zinc dithiophosphate is a dialkyl-, diaryl, or alkylaryl-zinc dithiophosphate. Selected from. Zinc dialkyldithiophosphate is particularly preferred.

  Examples of suitable commercially available zinc dithiophosphates are those available from Lubrizol Corporation under the trade names “Lz 1097” and “Lz 1395”, and from Chevron Oronite under the trade names “OLOA 26,7” and “OLOA 269R”. And those available from Ethyl under the trade name “HITEC 7197”; zinc dithiophosphates such as those available from Lubrizol Corporation under the trade names “Lz 677A”, “Lz 1095” and “Lz 1371”, from Chevron Oronite Available under the trade name “OLOA 262” and available from Ethyl under the trade name “HITEC 7169”; and zinc dithiophosphate such as Lubrizo Includes those available under the trade designations “Lz 1370” and “Lz 1373” from Corporation and those available under the trade designation “OLOA 260” from Chevron Orite.

  The lubricating oil composition according to the invention is generally in the range of 0.1 to 1.5% by weight, preferably in the range of 0.4 to 0.9% by weight, based on the total weight of the lubricating oil composition, and Most preferably, zinc dithiophosphate is included in the range of 0.45 to 0.8% by weight.

  Additional antiwear additives that can be conveniently used include molybdenum-containing compounds and boron-containing compounds.

  Examples of such molybdenum-containing compounds may conveniently include molybdenum dithiocarbamates such as trinuclear molybdenum compounds as described in WO-A-98 / 26030, molybdenum sulfides and molybdenum dithiophosphates.

  The molybdenum-containing antiwear additive is conveniently added to the lubricating oil composition of the present invention in an amount ranging from 0.1 to 3.0% by weight, based on the total weight of the lubricating oil composition.

  Boron-containing compounds that may be conveniently used include borate esters, borated fatty amines, borated epoxides, alkali metal borates (or mixed alkali or alkaline earth metals) and borated excess base metal salts.

  The boron-containing antiwear additive is conveniently added to the lubricating oil composition of the present invention in an amount ranging from 0.1 to 3.0% by weight, based on the total weight of the lubricating oil composition.

  The lubricating oil composition of the present invention may further contain one or more dispersants that can preferably be mixed in an amount ranging from 5 to 15% by weight based on the total weight of the lubricating oil composition.

  Examples of dispersants that can be used include polyalkenyl succinimides and polyalkenyl succinic esters disclosed in US Pat. Nos. 1,367,796, 1,667,140, 1,130,811 and 1,743,435. A preferred dispersant comprises boronated succinimide.

  Preferred lubricants that can be conveniently used include fatty acid amides, more preferably unsaturated fatty acid amides.

  The amount of lubricant that can be added to the lubricating oil composition of the present invention conveniently ranges from 0.05 to 1.2% by weight, based on the total weight of the lubricating oil composition.

  Polymethacrylates, such as those disclosed in patents 1195542 and 1264056, can be conveniently used as effective pour point depressants in the lubricating oil compositions of the present invention.

  In addition, compounds such as alkenyl succinic acid or its ester moiety, benzotriazole-based compounds and thiodiazole-based compounds can be conveniently used as anticorrosives in the lubricating oil compositions of the present invention.

  Compounds such as polysiloxanes, dimethylpolycyclohexane and polyacrylates can be conveniently used as antifoaming agents in the lubricating oil compositions of the present invention.

  Compounds that can be conveniently used as seal fixatives or seal compatibilizers in the lubricating oil compositions of the present invention are, for example, commercially available aromatic esters.

  The lubricating oil composition of the present invention comprises base oil blends as well as dispersants, detergents, antiwear agents, lubricants, thickeners, metal passivators, acid sequestering agents, pour point depressants, anticorrosives. It can be conveniently prepared by mixing one or more additives selected from antifoams, seal fixatives or seal compatibilizers and antioxidants.

  In another embodiment of the present invention, a method of lubricating a marine or stationary low speed crosshead diesel engine or trunk piston medium speed diesel engine comprising utilizing a lubricating oil composition as described above for the engine. Provided.

The invention will now be described by reference to the following examples, which are not intended to limit the scope of the invention in any way.
(Examples 1 and 2 and Comparative Examples A to C)
The lubricating compositions of the following examples were prepared by mixing a complete set of additives with a base oil and thickener blend until homogeneous.

  The composition of the prepared lubricating composition is shown in Table 1 below.

１．Ｒｏｙａｌ Ｄｕｔｃｈ／Ｓｈｅｌｌ Ｇｒｏｕｐ ｏｆ Ｃｏｍｐａｎｉｅｓから市販されている、１００℃にて約１１ｍｍ^２／秒の運動粘度を有する、溶剤抽出方法によって製造されたパラフィン系ＡＰＩグループＩ基油
２．Ｒｏｙａｌ Ｄｕｔｃｈ／Ｓｈｅｌｌ Ｇｒｏｕｐ ｏｆ Ｃｏｍｐａｎｉｅｓから市販されている、１００℃にて約３２ｍｍ^２／秒の運動粘度を有する、溶剤抽出方法によって製造されたパラフィン系ＡＰＩグループＩ基油
３．１００℃にて６６ｍ^２／秒の運動粘度、９８９ｋｇ／ｍ^３の密度および９℃の流動点を有する、Ｒｏｙａｌ Ｄｕｔｃｈ／Ｓｈｅｌｌ Ｇｒｏｕｐ ｏｆ Ｃｏｍｐａｎｉｅｓから市販されている脱アスファルトシリンダー油
４．米国特許第７３５４５０８号に記載された方法によって便利に調製され得る、１００℃にて約１９ｃＳｔの運動粘度、１４２の粘度指数、８３７ｋｇ／ｍ^３の密度および−２４℃の流動点を有するフィッシャー・トロプシュ由来グループＩＩＩ基油
５．ＷＯ０２／０７０６３１に記載された方法によって便利に調製され得る、１００℃にて約８ｍｍ^２／秒の運動粘度、１４３から１４８の粘度指数、８２８ｋｇ／ｍ^３の密度および−２４℃の流動点を有するフィッシャー・トロプシュ由来グループＩＩＩ基油
６．過剰塩基洗浄剤、抗摩耗剤としてのジチオリン酸亜鉛、安定剤、流動点降下剤および消泡剤を含む添加剤一式

1. 1. Paraffinic API Group I base oils produced by a solvent extraction method, commercially available from Royal Dutch / Shell Group of Companies, having a kinematic viscosity at 100 ° C. of about 11 mm ² / sec. Paraffinic API Group I base oil made by a solvent extraction method, commercially available from Royal Dutch / Shell Group of Companies, having a kinematic viscosity of about 32 mm ² / sec at 100 ° C. 3. 66 m ² at 100 ° C. ^3. Deasphalted cylinder oil commercially available from Royal Dutch / Shell Group of Companies having a kinematic viscosity of 1 / sec, a density of 989 kg / m ³ and a pour point of 9 ° C. Fischer-Tropsch having a kinematic viscosity of about 19 cSt at 100 ° C., a viscosity index of 142, a density of 837 kg / m ³ and a pour point of −24 ° C., which can be conveniently prepared by the method described in US Pat. No. 7,354,508. Origin Group III base oil 5. Having a kinematic viscosity of about 8 mm ² / sec at 100 ° C., a viscosity index of 143 to 148, a density of 828 kg / m ³ and a pour point of −24 ° C., which can be conveniently prepared by the method described in WO 02/070631 Fischer-Tropsch derived Group III base oil 6. Complete set of additives including overbased detergent, zinc dithiophosphate as antiwear agent, stabilizer, pour point depressant and antifoam

  The lubricant-fuel compatibility of Examples 1 and 2 and Comparative Examples A to C was tested according to the following test method.

Lubricant-Fuel Compatibility Test Method This method describes the procedure for determining the lubricant-fuel compatibility of a lubricant-fuel composition.

  The fuel batch used in the test method had the following composition / characteristics:

  The tests were performed using lubricant / fuel blend ratios of 100/0, 90/10, 80/20, 70/30 and 60/40. The blend formulation under test was stored in a conical, 220 mm long, 100 ml centrifuge tube at 60 ° C. for 12 weeks. Tubes were stored vertically. After 12 weeks, the amount of oil phase in the blend formulation was recorded.

  The results of the lubricant-fuel compatibility test are shown in Table 2 below.

  As can be seen from Table 2, the lubricating compositions of Examples 1 and 2 (according to the invention) are comparative example A (not according to the invention), especially when present in the lubricant-fuel blend at 60% by volume or more. The lubricant-fuel compatibility was significantly improved compared to the lubricating compositions of A to C.

Claims (14)

(I) one or more additives;
(Ii) at least 25% by weight of a first Fischer-Tropsch derived base oil having a kinematic viscosity in the range of 6 to 10 mm ² / sec at 100 ° C .; and (iii) at least 5% by weight at 100 ° C. A thickener selected from a second Fischer-Tropsch derived base oil having a kinematic viscosity in the range of 15 to 30 mm ² sec- ¹ , bright stock, deasphalted cylinder oil (DACO), polyisobutylene and mixtures thereof;
A lubricating composition comprising: a lubricating composition having a TBN of at least 20 mg KOH / g and a kinematic viscosity of at least 9 mm ² / sec at 100 ° C. The lubricating composition of claim 1, wherein the thickener is a Fischer-Tropsch derived base oil having a kinematic viscosity in the range of 18 to 22 mm ² / sec at 100 ° C. The lubricating composition of claim 1, wherein the thickener is a Fischer-Tropsch derived base oil having a kinematic viscosity in the range of 24 to 27 mm ² / sec at 100 ° C. Having kinetic viscosity of 9 mm 2 ^/ sec from the first Fischer-Tropsch derived base oil 7, the lubricating composition according to any one of claims 1 to 3.   5. Lubricating composition according to any of claims 1 to 4, wherein the first Fischer-Tropsch derived base oil is present at a level of at least 30% by weight of the composition.   6. Lubricating composition according to any of claims 1 to 5, wherein the first Fischer-Tropsch derived base oil is present at a level of at least 35% by weight of the composition.   A lubricating composition according to any preceding claim, wherein the thickener is present at a level of at least 20% by weight of the composition.   A lubricating composition according to any preceding claim, wherein the thickener is present at a level of at least 30% by weight of the composition.   A lubricating composition according to any preceding claim, wherein the thickener is present at a level of at least 35% by weight of the composition.   10. Lubricating composition according to any of claims 1 to 9, wherein the lubricating composition has a TBN of at least 30 mg KOH / g, preferably at least 40 mg KOH / g.   Lubricating composition that provides an oil phase of greater than 50 ml at a lubricant: fuel weight ratio of 60:40 or greater in a lubricant-fuel compatibility test method.   Use of a lubricating composition according to any of claims 1 to 11 for a medium speed 4 stroke engine.   Use of a lubricating composition according to claim 12, wherein the engine is a marine engine. Lubricants - for improving fuel compatibility, the lubricating composition, the use of a Fischer-Tropsch derived base oils having kinetic viscosities ranging from 6 mm 2 ^/ sec at 100 ° C. of 10 mm 2 ^/ sec.