EP1914295B1 - Marine lubricant for a low or high sulfur content fuel - Google Patents

Description

Field.

The present invention relates to a two-cycle marine engine cylinder lubricant for use with both high sulfur and low sulfur fuel oils. It relates more particularly to a lubricant having sufficient neutralization capacity vis-à-vis the sulfuric acid formed during the combustion of high-sulfur fuel oil, while limiting the formation of deposits during the use of fuel oils. low sulfur content.

Technological Background of the Invention

The marine oils used in slow-moving 2-stroke engines are of two types. The cylinder oils on the one hand, ensuring the lubrication of the cylinder piston assembly, and the system oils on the other hand, ensuring the lubrication of all moving parts out of the cylinder piston assembly. Within the cylinder piston assembly, the combustion residues containing acid gases are in contact with the lubricating oil.

Acid gases are formed from the combustion of fuel oils; they are in particular sulfur oxides (SO ₂ , SO ₃ ), which are then hydrolysed when in contact with the moisture present in the combustion gases and / or in the oil. This hydrolysis generates sulfurous acid (HSO ₃ ) or sulfuric acid (H ₂ SO ₄ ).

To preserve the surface of the liners and avoid excessive corrosive wear, these acids must be neutralized, which is usually done by reaction with the basic sites included in the lubricant.

The capacity of neutralization of an oil is measured by its BN or Base Number in English, characterizing its basicity. It is measured according to ASTM D-2896 and is expressed in equivalent weight of potash per gram of oil or mg of KOH / g. The BN is a standard criterion for adjusting the basicity of cylinder oils to the sulfur content of the fuel oil used, in order to neutralize all the sulfur contained in the fuel, and likely to be converted into sulfuric acid by combustion and hydrolysis.

Thus, the higher the sulfur content of a fuel oil, the higher the BN of a marine oil. Therefore, marine oils of BN ranging from 5 to 100 mg KOH / g are available on the market.

Environmental concerns have led in some areas, including coastal areas, to limit the sulfur content in fuel oils used on ships.

For example, MARPOL Annex 6 (Regulations for the Prevention of air pollution from ships) of IMO (International Maritime Organization) entered into force in May 2005. It provides for a maximum sulfur content of 4.5% m / m of fuel oils. as well as the creation of controlled release zones in sulfur oxides, called SECAs (SOx Emission Control Areas). Vessels entering these areas shall use fuel with a maximum sulfur content of 1.5% m / m or other alternative treatment to limit SOx emissions to meet the specified values. The notation% m / m denotes the weight percentage of a compound relative to the total weight of fuel oil or lubricating composition in which it is included.

Ships operating on trans-continental routes will then use several types of heavy fuel oil depending on local environmental constraints and this allows them to optimize their cost of operation.

Thus most of the container ships currently under construction provide for the implementation of several bunkers, for a high sulfur 'high seas' oil on the one hand and for a 'SECA' fuel with lower sulfur content or equal to 1.5% m / m on the other hand.

The switching between these two categories of fuel oil may require adaptation of the operating conditions of the engine, in particular the use of appropriate cylinder lubricants.

Currently, in the presence of high sulfur fuel oil (3.5% m / m and above), marine lubricants with a BN of about 70 are used.

In the presence of a fuel with a low sulfur content (1.5% m / m and less), marine lubricants with a BN of about 40 are used.

In these two cases, then a sufficient neutralization capacity is reached because the concentration required in basic sites provided by the overbased detergents of the marine lubricant is reached, but it is necessary to change the lubricant at each change of type of fuel oil.

In addition, each of these lubricants has limitations of use resulting from the following observations: the use of a BN 70 cylinder lubricant in the presence of a low sulfur fuel oil (1.5% w / w and less) and at fixed lubrication rate, creates a large excess of basic sites (strong BN) and a risk of destabilization of unused overbased detergent micelles, which contain insoluble metal salts. This destabilization results in the formation of insoluble metal salt deposits (eg calcium carbonate), mainly on the piston crown, and eventually can lead to a risk of excessive wear of polishing shirt.

As a result, the optimization of the cylinder lubrication of a slow 2-stroke engine then requires the selection of the lubricant with the BN adapted to the fuel oil and to the operating conditions of the engine. This optimization reduces the operating flexibility of the engine and requires a high degree of technical skill of the crew in defining the conditions under which the changeover from one type of lubricant to the other must be achieved.

In order to simplify the maneuvers, it would therefore be desirable to have a single cylinder lubricant for a two-stroke marine engine that can be used both with high sulfur content fuel oils and with low sulfur fuel oils.

The document US3178368 discloses a process for producing sulfurized and overbased alkaline earth metal phenates. These phenates are used in lubricating compositions as additives having acid neutralizing properties.

The document EP1630223 discloses the use of a hydrocarbon-substituted polyphenol structure compound, which compound is used as an anti-wear additive in a marine diesel engine composition.

The document EP0008193 discloses a lubricating composition for marine engines comprising a lubricating base oil, a hydrocarbyl amine and dispersants for the hydrocarbyl amine salts which may be formed during use.

Summary of the invention.

The object of the present invention is to provide a lubricating oil that can ensure good lubrication of the marine engine cylinder and can withstand the stresses of high sulfur fuel oils and the stresses of low sulfur fuel oils.

To this end, the present invention provides a cylinder lubricant having a BN determined according to ASTM D-2896 greater than or equal to 40 milligrams of potash per gram of lubricant, comprising a marine engine lubricating base stock and at least one overbased detergent. based on alkali or alkaline earth metals, characterized in that it additionally contains an amount of from 0.1% to 2% by weight, relative to the total weight of the lubricant, of one or more compounds (A) chosen from primary, secondary or tertiary mono-alcohols whose alkyl chain is saturated or comprises at most two ethylenic double bond unsaturations, said chain is linear or branched and comprises at least 12 carbon atoms.

Surprisingly, the Applicant has found that the introduction of certain types of surfactant compounds in a conventional cylinder lubricant formulation having a determined BN, leads to greatly increase the efficiency of said conventional lubricant vis-à-vis the neutralization of the lubricant. sulfuric acid formed during the combustion of any type of fuel whose sulfur content is less than 4.5% in a marine engine 2-stroke. The improvement in performance is particularly related to the rate or kinetics of neutralization of the sulfuric acid formed which is substantially increased.

This performance differential, between a conventional reference lubricant and the same surfactant additive lubricant, is characterized by a neutralization efficiency index measured using the enthalpy test described in the examples below.

In addition, the Applicant has found that the introduction of these surfactant compounds has no effect, or has a negligible effect on the initial BN value of said lubricant measured by ASTM D-2896.

Indeed, the Applicant has found that the BN does not appear to be the sole criterion for the adaptability of the lubricant to the sulfur content of the fuel used. Although giving an indication of the potential for neutralization, the BN is not necessarily representative of the availability and accessibility of the basic sites constituting the BN vis-à-vis the acid molecules to be neutralized.

Thus, without wishing to be bound by any theory, it can be envisaged that these surface-active compounds do not in themselves bring additional basicity to the lubricant in which they are dissolved. On the other hand, their hydrophilic / lipophilic balance (HLB) leads, when they are introduced into a lubricant with a given BN, to make the basic sites contained in the overbased detergents of the lubricant more accessible, and thus to make the reaction of the lubricant more efficient. neutralization of the sulfuric acid formed during the combustion of the fuel oil.

This makes it possible to formulate a 2-stroke marine engine cylinder lubricant suitable for both high sulfur and low sulfur fuel oils.

Preferably, the present invention provides a cylinder lubricant having a specific BN in the range of 40 to 70 milligrams of potash per gram of lubricant, preferably 50 to 60, or even more preferably 55 milligrams of potash per gram of lubricant. as described in the claims.

According to one embodiment, the compounds A are chosen from heavy monoalcohols which have a linear main alkyl chain having 12 to 24 carbon atoms, this linear chain being optionally substituted by one or more alkyl groups having 1 to 23 carbon atoms.

Preferably, the compounds A are chosen from myristic, palmitic, cetyl, stearic, eicosenoic and behenic alcohol. More preferably compound A is iso-tridecanol.

According to one embodiment, the cylinder lubricant comprises one or more functional additives chosen from dispersing additives, anti-wear agents, anti-foam additives, anti-oxidant and / or anti-rust additives.

According to one embodiment, the cylinder lubricant comprises at least one overbased detergent selected from the group consisting of carboxylates, sulfonates, salicylates, naphthenates, phenates, and mixed overbased detergents associating at least two of these types of detergents, especially lubricant. cylinder comprises at least 10% of one or more overbased detergent compounds.

According to one embodiment, the overbased detergents are compounds based on metals selected from the group consisting of calcium, magnesium, sodium or barium, preferably calcium or magnesium.

According to one embodiment, the overbased detergents are compounds based on metals selected from the group consisting of calcium, magnesium, sodium or barium, preferably calcium or magnesium.

In one embodiment the detergents are overbased with metal insoluble salts selected from the group of alkali metal and alkaline earth metal carbonates, hydroxides, oxalates, acetates, glutamates. Preferably, the overbased detergents are alkali or alkaline earth metal carbonates or at least one of the detergents is overbased with calcium carbonate.

In another embodiment, the cylinder lubricant comprises at least 0.1% of a dispersant additive selected from the family of succinimide PIBs.

According to another object, the invention relates to the use of a lubricant as described above as a single cylinder lubricant that can be used with any type of fuel oil whose sulfur content is less than 4.5%, preferably of which the Sulfur content is 0.5 to 4% w / w.

Preferably, the single cylinder lubricant is usable both with fuel oil with a sulfur content of less than 1.5% w / w and with fuel oils with a sulfur content of more than 3% w / w.

According to another object, the invention relates to the use of a lubricant as described above for preventing corrosion and / or reducing the formation of deposits of insoluble metal salts in two-stroke marine engines during the combustion of fuel. any type of fuel oil with a sulfur content of less than 4.5% m / m.

According to another object, the invention relates to the use of one or more compounds chosen from primary, secondary or tertiary monoalcohols whose alkyl chain is saturated or unsaturated, linear or branched and comprises at least 12 carbon atoms. , as surfactants in a cylinder lubricant having a BN, as measured by ASTM D-2896, greater than or equal to 40 milligrams of potash per gram of lubricant, to improve the efficiency of said cylinder lubricant with respect to the speed of neutralization of the sulfuric acid formed during the combustion of any type of fuel whose sulfur content is less than 4.5% m / m in a two-stroke marine engine.

In a preferred embodiment of the use described above, the surfactant is present in an amount of from 0.01% to 10% by weight, preferably from 0.1% to 2% by weight relative to the total weight lubricant.

According to another object the invention relates to a method of manufacturing a lubricant as described above in which compound A is added as a separate component of the cylinder lubricant having a BN determined according to the standard ASTM D-2896 greater than or equal to 40 milligrams of potassium hydroxide per gram of lubricant and optionally comprising one or more functional additives.

According to one embodiment, the lubricant is prepared by diluting a marine lubricant additive concentrate in which compound A is incorporated.

• de 0,5% à 15%, en poids par rapport au poids total du concentré d'additif, d'un ou plusieurs composés (A) choisis parmi les mono-alcools primaires, secondaires ou tertiaires dont la chaîne alkyl est saturée ou comprend au plus deux insaturations de type double liaison éthylénique, ladite chaîne est linéaire ou ramifiée et comprend au moins 12 atomes de carbone,
• des dispersants, détergents, additifs fonctionnels et huile de base de prédilution dans des proportions permettant d'obtenir après dilution dans une huile de base des lubrifiants cylindre ayant un BN supérieur ou égal à 40 selon ASTM D-2896.

According to another object the invention relates to an additive concentrate, for a cylinder lubricant having a BN determined according to ASTM D-2896 greater than or equal to 40 milligrams of potash per gram of lubricant, said concentrate comprising:

• from 0.5% to 15%, by weight relative to the total weight of the additive concentrate, of one or more compounds (A) chosen from primary, secondary or tertiary monoalcohols whose alkyl chain is saturated or comprises at most two ethylenic double bond unsaturations, said chain is linear or branched and comprises at least 12 carbon atoms,
• dispersants, detergents, functional additives and predilution base oil in proportions which make it possible, after dilution in a base oil, to obtain cylinder lubricants having a BN greater than or equal to 40 according to ASTM D-2896.

Preferably in the additive concentrate according to the invention, the heavy monoalcohols have a linear main alkyl chain having 12 to 24 carbon atoms, this linear chain being optionally substituted by one or more alkyl groups having 1 to 23 carbon atoms.

DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION

• Les tensioactifs sont des molécules possédant d'une part une chaîne à caractère lipophile (ou hydrophobe), et d'autre part un groupement à caractère hydrophile (ou tête polaire).

Heavy monoalcohols as surfactants :

• Surfactants are molecules having on the one hand a lipophilic (or hydrophobic) chain, and on the other hand a hydrophilic group (or polar head).

The heavy monohydric alcohols used in the invention are nonionic surfactants whose hydrophilic polar head is represented by an OH hydroxyl group and whose lipophilic part is represented by a carbon chain which contains enough carbon atoms to confer a lipophilic character. sufficient to the molecule.

In the invention, the heavy monohydric alcohols are used alone or in a mixture and are selected from primary, secondary or tertiary monoalcohols whose alkyl chain is saturated or unsaturated, linear or branched and comprises at least 12 carbon atoms.

In addition, the alkyl chain preferably comprises at most 60 carbon atoms.

Preferably, the alkyl chain comprises from 12 to 50 carbon atoms. It is saturated or generally comprises at most two unsaturations of ethylenic double bond type.

According to a preferred embodiment, the heavy monoalcohols have a linear main alkyl chain having 12 to 24 carbon atoms, this linear chain being optionally substituted by one or more alkyl groups having 1 to 23 carbon atoms.

The monoalcohols used in the invention generally come from the corresponding fatty acids according to known transformation methods. Preferably, for reasons of cost and availability, fatty acids of vegetable origin are used.

Thus, among the preferred linear monoalcohols, mention may be made, for example, of myristic, palmitic, cetyl, stearic, eicosenoic or behenic alcohols derived from the corresponding fatty acids.

Among the preferred branched monoalcohols there may be mentioned, for example, isotridecanol.

In a preferred embodiment of the invention, use will be made of linear alkyl chain monoalcohols comprising an even number of carbon atoms of between 12 and 24 carbon atoms.

Due to their low surfactant properties or strong lipophilic character, these compounds are stabilized in solution in the oil matrix and tend to shift the chemical equilibria within the overbased detergents. As a result, the basic sites provided by the overbased detergents are more accessible, which makes the sulfuric acid neutralization reaction more effective by these basic sites provided by the overbased detergents.

Note also that these compounds do not in themselves add additional basicity to the lubricant in which they are dissolved.

The present application describes that the amounts of surfactants used range from 0.1 to 2% by weight relative to the total weight of the lubricant.

It is possible to use a compound or a mixture of several compounds chosen from the monoalcohols defined above.

As the viscosity or the level of gelling of the final lubricant may vary according to the nature of the one or more heavy monoalcohol chosen, an amount in the range of 0.1% to 2% by weight of one or more monoalcohols relative to total weight of the lubricant. It will thus be possible to retain the final marine lubricant according to the invention, a viscosimetric grade conforming to the specifications of use.

BN lubricants according to the present invention.

The BN of the lubricants according to the present invention is provided by the overbased detergents based on alkaline or alkaline earth metals. The value of this BN measured according to ASTM D-2896 can vary from 5 to 100 mg KOH / g in marine lubricants.

A lubricant of BN value fixed will be chosen according to the conditions of use of said lubricants and in particular according to the sulfur content of the fuel oil used and in combination with the cylinder lubricants.

The lubricants according to the present invention are suitable for use as a cylinder lubricant, irrespective of the sulfur content of the fuel oil used as fuel in the engine.

As a result, the cylinder lubricants for two-stroke marine engines according to the invention have a BN greater than or equal to 40, preferably ranging from 40 to 70, or from 50 to 60, or even equal to 55.

According to a preferred embodiment of the invention, the lubricant formulation has a BN level, measured according to ASTM D-2896, intermediate between the levels required for the sulfur content limits of currently used fuel oils, that is, that is to say a BN of 50 to 60, preferably equal to 55. This is coupled with a formulation including heavy monoalcohol type surfactants, allowing increased accessibility of the basic sites provided by overbased detergents, so as to neutralize the as efficiently as conventional formulations of higher BN.

For example, a lubricating formulation according to the invention having a BN of 55 will have at least the same sulfuric acid neutralization efficiency as a traditional BN formulation of 70.

Conventional BN 55 oils, thus reformulated according to the invention can properly prevent corrosion problems when using fuel oils with high sulfur content (of the order of 3% m / m).

An oil according to the present invention also allows a reduction in the formation of insoluble metallic salt deposits providing overbasing (eg CaCO ₃ ) when using low sulfur fuel oils (1.5% w / w and less) this reduction is directly related to the lowering of the BN made possible in the present formulation configuration.

On the other hand, the lubricants according to the present invention retain sufficient detergency when formulated both for use with low and high sulfur fuel oils, since their BN (and hence the amount of detergents present) can be set at an intermediate level between that required for both categories of fuel oil.

Overbased detergents.

The overbased detergents used in the lubricating compositions according to the present invention are well known to those skilled in the art.

The detergents commonly used in the formulation of lubricating compositions are typically anionic compounds having a long lipophilic hydrocarbon chain and a hydrophilic head. The associated cation is typically a metal cation of an alkali or alkaline earth metal.

The detergents are preferably chosen from alkali metal or alkaline earth metal salts of carboxylic acids, sulphonates, salicylates and naphthenates, as well as the salts of phenates.

The alkaline and alkaline earth metals are preferably calcium, magnesium, sodium or barium.

These metal salts may contain the metal in an approximately stoichiometric amount or in excess (in an amount greater than the stoichiometric amount). In the latter case, we are dealing with so-called overbased detergents.

The excess metal providing the overbased detergent character is in the form of oil insoluble metal salts, for example carbonate, hydroxide, oxalate, acetate, glutamate, preferably carbonate.

In the same overbased detergent, the metals of these insoluble salts may be the same as those of the oil-soluble detergents or may be different. It is preferentially chosen from calcium, magnesium, sodium or barium.

The overbased detergents are thus in the form of micelles composed of insoluble metal salts maintained in suspension in the lubricating composition by the detergents in the form of oil-soluble metal salts.

These micelles may contain one or more types of insoluble metal salts, stabilized by one or more detergent types.

Overbased detergents with a single type of detergent soluble metal salt will generally be named after the nature of the hydrophobic chain of the latter detergent.

Thus, they will be said phenate, salicylate, sulfonate, naphthenate depending on whether this detergent is respectively a phenate, salicylate, sulfonate, or naphthenate.

The overbased detergents will be said to be of mixed type if the micelles comprise several types of detergents, different from each other by the nature of their hydrophobic chain.

For use in the lubricating compositions according to the present invention, the oil-soluble metal salts will preferably be phenates, sulphonates salicylates, and mixed detergents phenate-sulphonate and / or salicylates calcium, magnesium, sodium or barium.

According to a preferred embodiment of the present invention, the insoluble metal salt providing the overbased character is calcium carbonate.

The overbased detergents used in the lubricating compositions according to the present invention will preferably be phenates, sulphonates, salicylates and mixed detergents phenates-sulphonates-salicylates, overbased with calcium carbonate.

According to one embodiment of the present invention, at least 10% of one or more overbased detergent compounds is used, providing basicity to the lubricant in an amount sufficient to neutralize the acids formed upon combustion.

The amount of overbased detergents is typically determined to reach the targeted BN.

Base oils.

In general, the base oils used for the formulation of lubricants according to the present invention can be oils of mineral, synthetic or vegetable origin as well as their mixtures.

The mineral or synthetic oils generally used in the application belong to one of the classes defined in the API classification as summarized below: Saturated content Sulfur content Viscosity index Group 1 Mineral oils <90% > 0.03% 80 ≤ VI <120 Group 2 Hydrocracked oils ≥ 90% ≤ 0.03% 80 ≤ VI <120 Group 3 Hydroisomerized oils ≥ 90% ≤ 0.03% ≥ 120 Group 4 PAO Group 5 Other bases not included in groups 1 to 4

The Group 1 mineral oils can be obtained by distillation of selected naphthenic or paraffinic crudes and then purification of these distillates by methods such as solvent extraction, solvent or catalytic dewaxing, hydrotreatment or hydrogenation.

The oils of Groups 2 and 3 are obtained by more severe purification methods, for example a combination among hydrotreatment, hydrocracking, hydrogenation and catalytic dewaxing.

Examples of Group 4 and 5 synthetic bases include polyalphaolefins, polybutenes, polyisobutenes, alkylbenzenes.

These base oils can be used alone or as a mixture. A mineral oil can be combined with a synthetic oil.

Cylinder oils for 2-stroke marine diesel engines have a SAE-40 SAE-40 viscometric grade, typically SAE-50 equivalent to a kinematic viscosity at 100 ° C of between 16.3 and 21.9 mm ² / s. This viscosity can be obtained by mixing additives and base oils, for example containing Group 1 mineral bases such as Neutral Solvent bases (for example 500NS or 600 NS) and the Brightstock. Any other combination of mineral, synthetic or vegetable bases having, in admixture with the additives, a viscosity compatible with the grade SAE-50 may be used.

Typically, a conventional cylinder lubricant formulation for slow 2-cycle marine diesel engines is SAE 40 to SAE60, preferably SAE50 (SA37 J300) and includes at least 50% by weight of original lubricating base oil. mineral and / or synthetic, suitable for use in a marine engine, for example of API Group 1, that is to say obtained by distillation of selected crudes and purification of these distillates by processes such as solvent extraction , solvent or catalytic dewaxing, hydrotreatment or hydrogenation. Their Viscosity Index (VI) is between 80 and 120; their sulfur content is greater than 0.03% and their saturated content is less than 90%.

Functional additives.

The lubricant formulation according to the present invention may also contain functional additives adapted to their use, for example dispersant additives, anti-wear, anti-foam additives, anti-oxidant and / or anti-rust additives. These are known to those skilled in the art. These additives are generally present at a content by weight of 0.1 to 5%.

Dispersant additives.

Dispersants are well known additives used in the formulation of lubricating composition, especially for application in the marine field. Their primary role is to maintain in suspension the particles present initially or appearing in the lubricant composition during its use in the engine. They prevent their agglomeration by playing on steric hindrance. They can also have a synergistic effect on the neutralization.

The dispersants used as lubricant additives typically contain a polar group, associated with a relatively long hydrocarbon chain, generally containing from 50 to 400 carbon atoms. The polar group typically contains at least one nitrogen, oxygen or phosphorus element.

The compounds derived from succinic acid are dispersants particularly used as lubrication additives. Especially succinimides, obtained by condensation of succinic anhydrides and amines, succinic esters obtained by condensation of succinic anhydrides and alcohols or polyols.

These compounds can then be treated with various compounds including sulfur, oxygen, formaldehyde, carboxylic acids and compounds containing boron or zinc to produce, for example, borated succinimides or zinc-blocked succinimides.

Mannich bases, obtained by polycondensation of phenols substituted with alkyl groups, formaldehyde and primary or secondary amines, are also compounds used as dispersants in lubricants.

According to one embodiment of the present invention, at least 0.1% of a dispersing additive is used. It is possible to use a dispersant in the family of succinimide PIBs, for example borated or blocked with zinc.

Other functional additives.

The lubricant compositions according to the present invention may also optionally contain other additives,

For example, anti-wear additives, which may for example be chosen from the family of zinc dithiophosphates, antioxidant / anti-rust additives, for example organo-metallic or thiadiazole detergents, and anti-foam additives to counteract the effect of detergents, which may for example be polar polymers such as polymethylsiloxanes, polyacrylates.

According to the present invention, the compositions of the lubricants described refer to the compounds taken separately before mixing, it being understood that said compounds may or may not retain the same chemical form before and after mixing.

The surfactant compounds contained in the lubricants according to the present invention may in particular be incorporated in a lubricant as a separate additive, for example to increase the neutralization efficiency of a conventional lubricant formulation already known.

The surfactants according to the invention are in this case preferably included in a conventional cylinder lubricant formulation for slow 2-stroke marine diesel engines of grade SAE 40 to SAE60, preferably SAE50 (according to SAE classification J300).

• au moins 50% en poids d'huile de base lubrifiante d'origine minérale et/ou synthétique, adaptée à l'utilisation en moteur marin, par exemple, de classe API Groupe 1 c'est-à-dire obtenue par distillation de bruts sélectionnés puis purification de ces distillats par des procédés tels l'extraction au solvant, le déparaffinage au solvant ou catalytique, l'hydrotraitement ou l'hydrogénation. Leur Indice de Viscosité (VI) est compris en 80 et 120 ; leur teneur en soufre est supérieure à 0.03 % et leur teneur en saturé inférieure à 90 %
• au moins 10 % d'un ou plusieurs composés détergents surbasés, apportant la basicité au lubrifiant en quantité suffisante pour neutraliser les acides formés lors de la combustion, pouvant par exemple être choisi parmi les détergents de type sulfonate, phénate , salycilate;
• au moins 0.1% d'un additif dispersant pouvant par exemple être choisi dans la famille des PIB succinimides, et dont le rôle premier est de maintenir en suspension les particules présentes initialement ou apparaissant dans la composition lubrifiante au cours de son utilisation dans le moteur ; il présente également un effet synergique sur la neutralisation,
• et éventuellement des agents anti-mousse,anti-oxydants, et/ou anti-rouille, et/ou anti-usure comme par exemple ceux de la famille des dithiophosphates de zinc.

This classic formulation includes

• at least 50% by weight of lubricating base oil of mineral and / or synthetic origin, suitable for use in a marine engine, for example of API Group 1, that is to say obtained by distillation of crude selected and then purification of these distillates by methods such as solvent extraction, solvent or catalytic dewaxing, hydrotreating or hydrogenation. Their Viscosity Index (VI) is between 80 and 120; their sulfur content is greater than 0.03% and their saturated content is less than 90%
• at least 10% of one or more overbased detergent compounds, providing the basicity to the lubricant in an amount sufficient to neutralize the acids formed during the combustion, which may for example be chosen from sulphonate, phenate and salycilate detergents;
• at least 0.1% of a dispersing additive which may for example be chosen from the family of succinimide PIBs, and whose primary role is to keep in suspension the particles present initially or appearing in the lubricant composition during its use in the engine; it also has a synergistic effect on the neutralization,
• and optionally antifoaming agents, anti-oxidants, and / or anti-rust, and / or anti-wear such as those of the family of zinc dithiophosphates.

All mass percentages expressed are based on the total weight of the lubricant composition.

Additive concentrates for marine lubricants.

The surfactant compounds contained in the lubricants of the present invention may also be incorporated into a marine lubricant additive concentrate.

The marine cylinder lubricant additive concentrates generally consist of a mixture of the constituents described above, detergents, dispersants, other functional additives, pre-dilution base oil, in proportions which make it possible to obtain, after dilution in an oil base of the cylinder lubricants having a BN determined according to ASTM D-2896 greater than or equal to 40 milligrams of potash per gram of lubricant. This mixture generally contains, relative to the total weight of concentrate, a detergent content greater than 80%, preferably greater than 90%, a dispersant additive content of 2 to 15%, preferably 5 to 10%, a content of other functional additives from 0 to 5%, preferably from 0.1 to 1%.

According to one object of the invention, the additive concentrate for marine lubricant comprises one or more surfactants in a proportion which makes it possible to obtain an amount of surfactant in the lubricant cylinder according to the invention of 0.1 to 2%.

Thus, the marine lubricant additive concentrate contains, relative to the total weight of concentrate, from 0.5 to 15% by weight of one or more compounds (A) chosen from primary, secondary monoalcohols. or tertiary whose alkyl chain is saturated or comprises at most two ethylenic double bond unsaturation, said chain is linear or branched and comprises at least 12 carbon atoms.

All these% are expressed by weight relative to the total weight of the concentrate which also contains base oil in an amount sufficient to facilitate the use of said additive concentrate.

Differential performance measurement, between a traditional lubricant of:

reference and a lubricant according to the invention.

This measurement is characterized by a neutralization efficiency index measured according to the enthalpic test method described precisely in the examples and in which the progress of the exothermic neutralization reaction is followed by the rise in the temperature observed when the lubricant containing the basic sites is put in the presence of sulfuric acid.

Of course, the present invention is not limited to the examples and to the embodiment described and shown, but it is capable of numerous variants accessible to those skilled in the art.

Examples: Example 1: This example aims at describing the enthalpic test for measuring the neutralization efficiency of lubricants with respect to sulfuric acid

The availability or accessibility of the basic sites included in a lubricant, in particular lubricant cylinder for marine engine two times, vis-à-vis the acid molecules, can be quantified by a dynamic test of speed monitoring or kinetics of neutralization.

Principle :

The acid-base neutralization reactions are generally exothermic and it is therefore possible to measure the heat release obtained by reaction of sulfuric acid with the lubricants to be tested. This evolution is followed by the evolution of the temperature over time in an adiabatic reactor of the DEWAR type.

From these measurements, it is possible to calculate an index quantifying the effectiveness of an additive lubricant according to the present invention with respect to a lubricant taken as a reference.

This index is calculated relative to the reference oil to which the value of 100 is attributed. This is the ratio between the neutralization reaction times of the reference (S _ref ) and the measured sample (S _mes ). : $$\mathrm{Neutralization\; efficiency\; index}={\mathrm{S}}_{\mathrm{ref}}/{\mathrm{S}}_{\mathrm{my}}\mathrm{x}\mathrm{100}$$

The values of these neutralization reaction times, which are of the order of a few seconds, are determined from the acquisition curves of the increase in temperature as a function of time during the neutralization reaction. (See curve figure 1 ).

The duration S is equal to the difference t _f - t _i between the time at the end of reaction temperature and the time at the reaction start temperature.

The time t _i at the reaction start temperature corresponds to the first rise in temperature after stirring is started.

The time t _f at the final reaction temperature is that from which the temperature signal remains stable for a duration greater than or equal to half the reaction time.

The lubricant is all the more effective as it leads to short periods of neutralization and therefore to a high index.

Equipment used :

The reactor and agitator geometries as well as the operating conditions were chosen so as to be in a chemical regime, where the effect of the diffusional stresses in the oil phase is negligible.

Therefore in the configuration of the material used, the fluid height must be equal to the inside diameter of the reactor, and the stirring propeller must be positioned at about 1/3 of the height of the fluid.

The apparatus consists of a cylindrical type adiabatic reactor of 250 ml, the internal diameter of which is 48 mm and the inner height of 150 mm, of a stirring rod provided with a propeller with inclined blades, 22 mm in diameter; the diameter of the blades is between 0.3 and 0.5 times the diameter of the DEWAR, that is to say from 9.6 to 24 mm.

The position of the propeller is set at a distance of 15 mm from the bottom of the reactor. The stirring system is driven by a variable speed motor of 10 to 5000 rpm and a temperature acquisition system as a function of time.

This system is suitable for measuring reaction times of the order of 5 to 20 seconds and the temperature rise measurement of a few tens of degrees from a temperature of about 20 ° C to 35 ° C preferably about 30 ° C. The position of the temperature acquisition system in the DEWAR is fixed.

The stirring system will be adjusted so that the reaction occurs in a chemical regime: in the configuration of the present experiment, the speed of rotation is set at 2000 rpm, and the position of the system is fixed.

Moreover, the chemical regime of the reaction is also dependent on the oil height introduced into the DEWAR, which must be equal to the diameter of the latter, and which corresponds in the context of this experiment to the mass of 70 g of the lubricant tested.

3.5 g of 95% concentrated sulfuric acid and 70.0 g of lubricant to be tested are introduced into the reactor.

After placing the stirring system inside the reactor so that the acid and the lubricant mix well and repeatedly between two tests, the acquisition system and stirring are started in order to follow the reaction.

3.5 g of acid are introduced into the reactor.

70.0 g of lubricant brought to a temperature of about 30 ° C. are then introduced.

The acquisition system is started and the stirring system is set to go into chemical mode.

Implementation of the enthalpic test - calibration:

To calculate the efficiency indices of the lubricants according to the present invention by the method described above, we have chosen to take as a reference the neutralization reaction time measured for a two-stroke marine engine cylinder oil of BN 70 (measured by ASTM D-2896), having no surfactant additive according to the present invention.

This oil is obtained from a mineral base obtained by mixing a distillate of density at 15 ° C of between 880 and 900 Kg / m ³ with a distillation residue having a density of between 895 and 915 Kg / m. ³ (Brightstock) in a distillate / residue ratio of 3.

To this base is added a concentrate in which a calcium sulphonate of BN equal to 400 mg of KOH / g, a dispersant, a calcium phenate of BN equal to 250 mg of KOH / g in the quantity necessary to obtain a lubricant are found. BN 70 mg KOH / g.

The lubricant thus obtained has a viscosity at 100 ° C of between 19 and 20.5 mm ² / s.

The neutralization reaction time of this oil (hereinafter referred to as Href) is 10.3 seconds and its neutralization efficiency index is set to 100.

Two other lubricant samples of BN 55 and 40 are prepared from the same additive concentrate diluted respectively by 1.25 and 1.7 according to the desired BN and a lubricating base whose mixture of the distillate and the residue is adapted to obtain in the end a viscosity at 100 ° C of between 19 and 20.5 mm ² / s.

These two samples, hereinafter referenced H55 and H40 are also free of surfactant additive additives according to the present invention.

Table 1 below shows the values of the neutralization indices obtained for the BN 40 and 55 samples prepared by dilution of the additives included in the BN 70 reference oil. <u> Table 1 </ u> BN Neutralization efficiency index href 70 100 H 55 55 88 H 40 40 77

Example 2 : This example describes the influence of the additives according to the invention for a constant BN formulation 55.

The reference is the cylinder oil for two-stroke marine engine BN 70, not additive according to the present invention, and referenced Href in the previous example.

The samples additive BN 55 to be tested are prepared from the non-additive lubricant referenced H 55 in the previous example.

• on introduit x g de tensioactif
• on complète à 100 g avec le lubrifiant H55 à additiver.

These samples are obtained by mixing in a beaker at a temperature of 60 ° C., with stirring sufficient to homogenize the mixture of lubricant H55 to be added and the surfactant selected. For a mixture of x% m / m content in surfactant:

• we introduce xg of surfactant
• one completes to 100 g with lubricant H55 with additiver.

Table 2 below groups the values of the efficiency indices of the different samples thus prepared.

The BNs of the lubricants before and after introduction of the surfactants according to the present invention were also measured according to ASTM D-2896. <u> Table 2 </ u> Non additive lubricant Additives (gross formula) (% M / m) Neutralization efficiency index BN (mg KOH / g) href 100 68.6 H 55 88 55.4 Lorol C12 (C10: 0-2%, C12: <98%, C16: 0-2%) 0.5% 93 56.7 Lorol C14 (C12: 0-5%, C14: 95-100%, C16: 0-3%) 0.5% 110 56.5 Lorol C16 (C14: 0-3%, C16: <95%, C18: 0-5%) 0.5% 107 56.1 Lorol Technish (<C12: 0-3%, C12: 48-58, C14: 18-24%, C16: 8-12%, C18: 11-15%,> C18: 0-1%) 0.1% 91 54.7 Lorol Technish 1% 98 54.7 Cetyl Alcohol (C16H340) 95% Min 0.5% 117 54.5 Cetyl alcohol (C16H34O) 1% 127 54.3 Stearic alcohol (C18H38O) 96% mini 0.1% 109 55.0 Stearic alcohol (C18H38O) 0.5% 115 56.6 Stearic alcohol (C18H38O) 1% 117 54.0 Eicosanol (C20H42O) 96% mini 0.1% 99 54.6 Eicosanol (C20H42O) 0.5% 122 56.8 Eicosanol (C20H42O) 1% 117 54.3 Stenol (C 16: 0-0.3%, C 18: 0-3%, C20: 12-17%: C22: 80-85%, C24: 0-3%) 0.1% 109 54.6 Sténol 0.5% 113 54.6

It can be seen that the lubricants with additives according to the present invention have, at BN 55, a neutralization efficiency index higher than that of the same oil of BN 55 not thus additive.

Almost all BN 55 oils additivated according to the present invention have a higher neutralization efficiency index than that of a non-additivated BN 70 oil taken as a reference.

The index values calculated for BN 55 oils according to the present invention are overall from 9 to 27% higher than the reference, even though the introduction of the additives according to the present invention has no influence on the value. of their BN.

Claims (23)

1. Cylinder lubricant having a BN determined according to the standard ASTM D-2896 greater than or equal to 40 milligrams of potash per gram of lubricant, comprising a lubricant base stock for marine engines and at least one overbased detergent based on alkali metals or alkaline-earth metals, characterized in that it also contains

   • a quantity of 0.1% to 2% by weight relative to the total weight of the lubricant, of one or more (A) compounds chosen from the primary, secondary or tertiary monoalcohols the alkyl chain of which is saturated or comprises at most two unsaturations of the ethylenic double bond type, said chain is linear or branched and comprises at least 12 carbon atoms.
2. Cylinder lubricant according to claim 1 having a determined BN comprised within the range of 40 to 70 milligrams of potash per gram of lubricant.
3. Cylinder lubricant according to claim 1 or 2 in which the A compound or compounds is (are) chosen from the heavy monoalcohols which have a linear main alkyl chain having 12 to 24 carbon atoms, this linear chain being optionally substituted by one or more alkyl groups having 1 to 23 carbon atoms.
4. Lubricant according to one of claims 1 to 3 in which the A compound or compounds is (are) chosen from the myristic, palmitic, cetylic, stearic, eicosenoic, behenic alcohols.
5. Lubricant according to one of claims 1 to 3 in which the A compound is isotridecanol.
6. Cylinder lubricant according to one of claims 1 to 5 which comprises one or more functional additives chosen from the dispersant, anti-wear additives, anti-foam additives, anti-oxidant and/or anti-rust additives.
7. Cylinder lubricant according to one of claims 1 to 6 which comprises at least one overbased detergent chosen from the group constituted by the carboxylates, sulphonates, salicylates, naphthenates, phenates, and the mixed overbased detergents combining at least two of these types of detergents.
8. Cylinder lubricant according to one of claims 1 to 7 which comprises at least 10% of one or more overbased detergent compounds.
9. Lubricant according to any one of claims 1 to 8 in which the overbased detergents are metal-based compounds chosen from the group constituted by calcium, magnesium, sodium or barium.
10. Lubricant according to any one of claims 1 to 9 in which the detergents are overbased by insoluble metallic salts chosen from the group of carbonates, hydroxides, oxalates, acetates, glutamates of alkali and alkaline-earth metals.
11. Lubricant according to one of claims 1 to 10 in which the overbased detergents are carbonates of alkali or alkaline-earth metals.
12. Lubricant according to one of claims 1 to 11 in which at least one of the detergents is overbased by calcium carbonate.
13. Cylinder lubricant according to one of claims 1 to 12 which comprises at least 0.1 % of a dispersant additive chosen from the family of the PIB succinimides.
14. Use of a lubricant according to any one of claims 1 to 13 as a single cylinder lubricant which can be used with any type of fuel oils the sulphur content of which is less than 4.5% m/m.
15. Use of a lubricant according to any one of claims 1 to 13 as a single cylinder lubricant which can be used both with fuel oils with a sulphur content of less than 1.5% m/m and with fuel oils with a sulphur content of greater than 3% m/m.
16. Use of a lubricant according to one of claims 1 to 13 for preventing corrosion and/or reducing the formation of deposits of insoluble metallic salts in two-stroke marine engines during the combustion of any type of fuel oil the sulphur content of which is less than 4.5% m/m.
17. Use of one or more compounds chosen from the primary, secondary or tertiary monoalcohols the alkyl chain of which is saturated or unsaturated, linear or branched and comprises at least 12 carbon atoms, as surfactants in a cylinder lubricant having a BN, measured by the standard ASTM D-2896, greater than or equal to 40 milligrams of potash per gram of lubricant, in order to improve the effectiveness of said cylinder lubricant vis-à-vis the rate of neutralization of the sulphuric acid formed during the combustion of any type of fuel oils the sulphur content of which is less than 4.5% m/m in a two-stroke marine engine.
18. Use according to claim 17 in which the surfactant is present in a quantity of 0.01 % to 10% by weight relative to the total weight of the lubricant.
19. Use according to claim 17 or 18 in which the cylinder lubricant has features such as those defined in any one of claims 1 to 13.
20. Production process for a lubricant according to any one of claims 1 to 13 in which the A compound is added as a separate component of the cylinder lubricant having a BN determined according to the standard ASTM D-2896 greater than or equal to 40 milligrams of potash per gram of lubricant and optionally comprising one or more functional additives.
21. Production process for a lubricant according to any one of claims 1 to 13 by dilution of a concentrate of additives for a marine lubricant into which the A compound is incorporated.
22. Concentrate of additives for a cylinder lubricant having a BN determined according to the standard ASTM D-2896 greater than or equal to 40 milligrams of potash per gram of lubricant, said concentrate comprising: a) from 0.5% to 15%, by weight relative to the total weight of the additive concentrate, of one or more (A) compounds chosen from the primary, secondary or tertiary monoalcohols the alkyl chain of which is saturated or comprises at most two unsaturations of the ethylenic double bond type, said chain is linear or branched and comprises at least 12 carbon atoms, b) dispersants, detergents, functional additives and predilution base stock in proportions making it possible to obtain, after dilution in a base stock, cylinder lubricants having a BN greater than or equal to 40 according to ASTM D-2896.
23. Concentrate of additives according to claim 22 in which the heavy monoalcohols have a linear main alkyl chain having 12 to 24 carbon atoms, this linear chain being optionally substituted by one or more alkyl groups having 1 to 23 carbon atoms.

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