KR100286781B1 - Fuel composition - Google Patents

Abstract

The present invention relates to a fuel oil composition comprising a small amount of wear-reducing additive comprising an amount of distillate fuel in a liquid hydrocarbon having a sulfur concentration of 0.2% by weight or less based on the weight of the fuel and an ester for increasing the lubricity of the fuel. It is about.

Description

Fuel composition

The present invention relates to fuel compositions useful, for example, for improving lubricity and reducing wear in diesel engines.

The art describes esters as additives for diesel engine fuels. For example, US-A-2,527,889 describes polyhydroxy alcohol esters as the main corrosion resistant additives of diesel engine fuels, and GB-A-1,505302 includes, for example, glycerol monoesters and glycerol diesters as diesel fuel additives. Described ester formulations have the advantage of including reducing the wear of the fuel injection device, piston ring and cylinder liner.

However, GB-A-1,505,302 relates to overcoming operational problems of corrosion and abrasion by acidic combustion products which are residues in combustion chambers and exhaust systems. The document mentions that this problem is due to incomplete combustion under certain operating conditions. Typical diesel fuels used at the time of this document contain, for example, 0.5 to 1% by weight of sulfur (elemental sulfur), based on the weight of the fuel.

Many countries now will reduce or reduce the sulfur content in diesel fuels for environmental reasons, such as the reduction of sulfur dioxide emissions. Therefore, the sulfur content of the heating oil and diesel fuel is controlled to a maximum of 0.2% by weight by the CEC, and in the second stage the maximum content in the diesel fuel will be 0.05% by weight. The transition to a maximum of 0.05% needs to be completed during 1996.

The method of producing a low sulfur content fuel while reducing the sulfur content also reduces the content of other components of the fuel, such as the polyaromatic light polar component. Reducing one or more of the sulfur, polyaromatic and polar components in the fuel creates new problems in fuel use, i.e. the ability of the fuel to lubricate the injection system of the engine is reduced such that the fuel injection pump of the engine In high pressure rotary distributors, in-line pumps and unit injectors and injectors, they can fail relatively early in service life. This serious failure comes from a completely different wear than the corrosive wear problem described in GB-A-1,505302.

As mentioned, the failure occurs early in the engine life, while the wear problems mentioned in GB-A-1,505302 occur later in the engine life. Problems caused by low sulfur diesel fuels are described, for example, in D. Wei and H. Spikes, Wear, Vol. 111, No. 2, p. 217, 1986; And in R. Caprotti, C. Bovington, W. Fowler and M. Taylor SAE paper 922183; SAE fue1s and lubes, meeting Oct. 1992; San Francisco, USA.

It has been found that the aforementioned wear problems resulting from the use of low sulfur content fuels can be reduced or solved by providing certain additives in the fuel.

Thus, a first aspect of the invention mainly comprises a liquid hydrocarbon heavy distillate fuel oil having a sulfur concentration of 0.2 wt% or less, and an additive comprising an ester of a carboxylic acid having from 2 to 50 carbon atoms and an alcohol having at least one carbon atom. A fuel oil composition comprising a small amount.

A second aspect of the present invention is the use of a fuel oil composition as defined in the first aspect of the present invention for adjusting the wear rate of an injection system of an engine during engine operation in a compression-ignition (diesel) engine.

A third aspect of the invention is a method of operating a compression-ignition (diesel) engine comprising adjusting the wear rate of the injection system of the engine by providing a fuel oil composition as defined in the first aspect of the invention as the oil of the engine.

In the examples herein, the effect of reducing wear when the additive of the present invention is used in the fuel oil of the present invention will be described.

While not wishing to be bound by any theory, in the use of the composition in a compression-ignition internal combustion engine, the additive may be at least partly a single molecular layer or multiple on the injection system surface over the range of operating conditions of the engine, in particular on the injector pump surface in contact with each other during movement Compared to compositions that can form a molecular layer and that do not use additives, such compositions may be characterized by the relative movement of two or more loaded body parts under reduced wear, reduced friction or non-hydrodynamic lubrication conditions. At least one of increasing the electrical contact resistance in the test is raised.

The features of the invention will be described in detail below.

Additive

As mentioned, it is contemplated that an additive, which may be a single additive or an additive mixture, may form at least a partial layer on a particular surface of the engine. This means that the layer formed does not need to be formed completely on the contact surface. Thus, it may cover only a portion of the surface area of the contact surface, such as at least 10%, or at least 50%. The formation of the layer and the degree of coating of the contact surface can be elucidated, for example, by measuring the electrical contact resistance or the electrical capacitance.

Test examples that can be used to evaluate one or more of reduced wear, reduced friction or increased electrical contact resistance in accordance with the present invention are described below in the Ball On Cylinder Lubricant Evaluator and High Frequency Reciprocating Rig Tests. High Frequency Reciprocating Rig test).

Acids, alcoholic light esters will be discussed in more detail below.

(Ⅰ) mountain

The acid from which the ester is derived is preferably aliphatic, saturated or unsaturated, straight or branched chain, mono or polycarboxylic acid such as mono and dicarboxylic acid. For example, acids can be generalized to the following general formula:

R '(COOH) x

Wherein x is an integer of at least 1, such as from 1 to 4, and R 'is a monovalent or polyvalent, having from 2 to 50 carbon atoms and corresponding to the x value of the -COOH group and different carbon sources if at least one -COOH group is present Represents a hydrocarbyl group that is optionally substituted on a magnetic phase.

"Hydrocarbyl" means a group containing carbon and hydrogen bonded to the remainder of the molecule via a carbon atom. It may be straight or branched chain which may be interrupted by one or more hetero atoms such as 0, S, N or P, may be saturated or unsaturated, may be aliphatic or alicyclic or aromatic comprising heterocyclic or substituted It may not be substituted. When the acid is a monocarboxylic acid it is preferred that the hydrocarbyl group is an alkyl group or an alkenyl group having from 10 (ie 12) to 30 carbon atoms, ie the acid is saturated or unsaturated. Alkenyl groups may have one or more double bonds, such as one, two or three. Examples of saturated carboxylic acids are those having from 10 to 22 carbon atoms, such as capric acid, lauric acid, myristic acid, palmitic acid and behenic acid. And 10 to 22 carbon atoms, such as liconoleic acid, eleostearic acid, linoleic acid, linolenic acid, eicosanoic acid, galoleic acid, erucic acid and hippoic acid. When the acid is a polycarboxylic acid having 2 to 4 carboxy groups, the hydroxycarbyl group is preferably substituted or unsubstituted polymethylene.

(Ii) alcohol

The alcohol from which the ester is derived may be a polyhydroxy alcohol such as monohydroxy alcohol or trihydroxy alcohol. For example, alcohols can be generalized to the general formula:

R ² (OH) y

In the above formula,

y is an integer of 1 or more, R ² is a hydrocarbyl group having one or more carbon atoms, such as 10 or less carbon atoms, monovalent or polyvalent corresponding to the y value of the -OH group, and one or more -OH groups are present They are optionally substituted on different carbon atoms.

"Hydrocarbyl" has the same meaning as defined for the above acid. In the case of alcohols, the hydrocarbyl group is preferably an alkyl group or a substituted or unsubstituted polymethylene group. Examples of monohydric alcohols are lower alkyl alcohols having 1 to 6 carbon atoms, such as methyl, ethyl, propyl and butyl alcohols.

Examples of polyhydric alcohols have 2 to 10, preferably 2 to 6, more preferably 2 to 4 hydroxy groups in the molecule, and 2 to 90, preferably 2 to 30, more preferably Aliphatic saturated or unsaturated, straight or branched chain alcohols having 2 to 12, most preferably 2 to 5 carbon atoms. More specific examples of polyhydric alcohols may be glycols or dihydric alcohols such as diols or glycerol.

(Ⅲ) ester

The esters can be used alone or as a mixture with one or more esters and can consist only of carbon, hydrogen and oxygen.

It is preferable that the ester has a molecular weight of 200 or more, or has 10 or more carbon atoms, or both.

Examples of esters that can be used are lower alkyl esters such as the methyl esters of saturated or unsaturated monocarboxylic acids cited above. Such esters may be obtained, for example, by saponifying and esterifying vegetable or animal natural fats or oils, or by transesterifying them with lower aliphatic alcohols.

Examples of esters of polyhydric alcohols that may be used are those in which all hydroxy groups are esterified, not all hydroxy groups are all esterified, and mixtures thereof. Specific examples are esters prepared from trihydric alcohols and one or more of the aforementioned saturated or unsaturated carboxylic acids, such as glycerol monoesters and glycerol diesters (eg, glycerol monooleate, glycerol dioleate and glycerol monostearate). The polyhydric esters can be purchased as prepared and / or commercially available by esterification as described in the art.

The ester may have one or more free hydroxy groups.

Fuel oil

The sulfur concentration is preferably 0.05% by weight or less, such as 0.01% by weight or less, and can be reduced to 0.OO5% by weight or 0.OOO1% by weight or less.

The art describes methods for reducing the sulfur concentration of hydrocarbon distillate fuels, such as, for example, solvent extraction, sulfuric acid treatment and hydrodesulphurisation.

"Tricyclic aromatic" means a fixed system in which three aromatic rings are fused together. The fuel preferably contains less than 1% by weight of the above components.

Examples of "polar components" are compounds, esters and alcohols containing 0, S or N.

The abrasion problem mentioned above has been found to be more severe as the polar component concentration of the fuel is reduced, e.g. when the polar component concentration in the fuel is less than 250 ppm, such as less than 200 ppm, specifically 170 ppm and It is especially severe at 130 ppm. The polar component concentration can be conveniently measured by high pressure liquid chromatography (often referred to as HPLC).

Heavy distillate fuel oils that may be used in the present invention generally boil in the range of about 100 to about 500 ° C, such as about 150 to about 400 ° C. The fuel oil may comprise a blend of atmospheric distillate or vacuum distillate or cracked gas oil or any proportion of straight material and heated and / or catalytic cracked distillate. The most common petroleum distillates are kerosene, jet fuel, diesel fuel, heating oil and heavy fuel oil, with diesel fuel being preferred for the reasons mentioned above. The heating oil may be an atmospheric straight oil material and may contain up to 35% by weight of vacuum gas oil or cracked gas oil or both.

The concentration of the additive of the present invention in the fuel oil is 250, OO ppm or less, such as, for example, 10, OO ppm or less, preferably 1-500 ppm, more preferably such as 1 to 1000 ppm (active ingredient), relative to the fuel weight. May be from 10 to 200 ppm.

The additive may be incorporated into the bulk fuel oil by methods known in the art. Conveniently, the additive may be incorporated in the form of a concentrate comprising a mixture of the liquid carrier medium and the additive compatible with the fuel oil, where the additive is dispersed in the liquid medium. The concentrate preferably contains 3 to 75% by weight, more preferably 3 to 60% by weight, most preferably 10 to 50% by weight of additives, preferably as a solution in oil. Examples of carrier liquids are organic solvents including hydrocarbon solvents, for example petroleum fractions such as naphtha, kerosene and heating oils; Aromatic hydrocarbons; Paraffinic hydrocarbons such as hexane and pentane; And alkoxyalkanols such as 2-butoxyethanol. Carrier liquids should be selected in view of compatibility with additives and fuels.

Auxiliary additives

The additives of the present invention may be used alone or as a mixture with one or more additives. They may also be used as a combination with one or more auxiliary additives as known in the art, for example detergents, antioxidants (fuel decomposition), corrosion inhibitors, dehazers, emulsifiers, metals Deactivators, defoamers, cetane improvers, auxiliary solvents, package compatibilizers and middle distillate cold flow improvers.

The following examples illustrate the invention. The following materials and procedures were used and the results are as follows.

additive

D: glycerol monooleate

E: di-isodecyl adipate

fuel

The used fuels indicated by I and II are diesel fuels having the following characteristics.

I S content <0.01% (weight / weight)

Aromatic Content 〈1% (Weight / Weight)

Cetane number 55.2 to 56.1

Cold Filter Occlusion Point Temperature (CFPPT)

Cold Filter Plugging Point Temperature -36 ℃

95% boiling point 273 ℃

II S content <0.01% (weight / weight)

No aromatic content measured

Does not measure cetane number

CFPPT -41 ℃

95% boiling point 263 ℃

exam

Certain additives D and E were dissolved in specific fuels I and II and the resulting compositions were tested using the following method.

Ball meter (ie BOCLE) testing on cylinder lubricants: Friction and Wear devices, 2nd Ed., P 280, American Society of Lubrication Engineers, Park Ridge III, USA; And F. Tao and J. Appledorn, ASLE trans., 11, 345-352 (1968).

High frequency reciprocating rig (ie HFRR) test: D. Wei and H. Spikes, Wear, Vol. 111, No. 2, p. 217, 1986; And in R. Caprotti, C. Bovington, W. Fowler and M. Taylor SAE paper 922183; SAE fuels and lubes. meeting Oct. 1992; San Francisco, USA].

Both methods provide a method of measuring the lubricity of the fuel.

result

The results are shown in the table below.

(A) BOCLE test

The results are shown as wear scar diameter. Therefore, a lower value means less wear occurs than a larger value. All tests were performed at ambient temperature.

Fuel Ⅰ

Fuel II

(B) HFRR test

The results are expressed in wear mark diameters. In addition, the friction coefficient was measured. The test was performed at the different temperatures indicated. In fuel I, the concentration of additive D was 200 ppm (weight / weight) and the concentration of additive E was 10,000 ppm. In Fuel II, the concentration of additive D is indicated in parentheses.

Fuel Ⅰ

Fuel II

The results show that lubricity is improved by using additives D and E.

Claims (19)

But most of the amount of diesel fuel oil having a sulfur concentration of 0.2% by weight or less and an additive comprising a ester of a carboxylic acid having from 2 to 50 carbon atoms and an alcohol having at least one carbon atom, provided that the additive (A) A fuel oil composition, wherein the additive is not a mixture of a partial ester of an alcohol with a fatty acid and a polybasic or polybasic ester, and (B) the additive does not comprise a reaction product between the dicarboxylic acid and the oil-insoluble glycol. The composition of claim 1, wherein the sulfur concentration is at most 0.5% by weight. The composition of claim 2 wherein the sulfur concentration is no more than 0.1 wt%. The composition according to claim 1, wherein the acid from which the ester is derived has the general formula R′COOH, wherein R ′ is a hydrocarbyl group. 5. The composition of claim 4, wherein the acid is saturated with 10-30 carbon atoms or unsaturated by having 1 to 3 double bonds in the alkenyl group. 6. The composition of claim 5 wherein the acid has 12 to 22 carbon atoms. The poly of any one of claims 1 to 3, wherein the acid is of the general formula R ² (COOH) x wherein x is an integer from 2 to 4 and R ² is a substituted or unsubstituted polymethylene group. Carboxylic acid. 8. The composition of claim 7, wherein the acid is a dicarboxylic acid. The composition of claim 1, wherein the alcohol is an alkyl alcohol having 1 to 6 carbon atoms. The composition of claim 9 which is alcohol and methanol. 9. The composition of claim 1, wherein the alcohol is an aliphatic, saturated or unsaturated, straight or branched chain polyhydric alcohol having 2 to 10 hydroxy groups and 2 to 90 carbon atoms in the molecule. 10. The composition of claim 11 wherein the alcohol has from 2 to 4 hydroxy groups and from 2 to 5 carbon atoms in the molecule. 13. The composition of claim 12, wherein the alcohol is glycerol. The composition of claim 13 wherein the ester is glycerol monooleate. The composition of claim 1, wherein the concentration of the additive in the fuel oil is from 10 to 10,000 ppm by weight of active ingredient per fuel oil charge. The composition of claim 15 wherein the concentration is between 100 and 200 ppm. Use of a fuel oil composition according to any of the preceding claims used as a fuel for the diesel engine to adjust the wear rate in the injection system of the engine during engine operation in a diesel engine. A method of operating a compression-ignition engine comprising adjusting the wear rate in an injection system of the engine by providing the compression-ignition engine with the fuel oil composition according to any one of the preceding claims as a fuel. 19. Use and method according to claim 17 or 18, wherein wear occurs in the injection pump of the engine.