FI120792B - fuel composition - Google Patents

Abstract

A fuel oil composition comprises a major proportion of a liquid hydrocarbon middle distillate fuel having a sulphur concentration of 0.2 % or less by weight based on the weight of the fuel, and a minor proportion of a wear-reducing additive comprising an ester for increasing the lubricity of the fuel.

Description

This invention relates to fuel compositions which provide, for example, improved lubrication and reduced wear in diesel engines.

Esters have been described in the art as additives in diesel fuel. For example, US-A-2527889 describes polyhydroxy alcohol-10 esters as primary corrosion inhibiting additives in diesel fuel, and GB-A-1505302 describes wear.

However, GB-A-1505302 focuses on the operational disadvantages of corrosion and wear due to acidic combustion products, residues in the combustion chamber and exhaust-gas system. The document mentions that these disadvantages are due to incomplete combustion under certain operating conditions. Typically, diesel fuels are covered by the document. * :. available at the time of completion, for example, contained 0.5 to 1% by weight of sulfur as elemental sulfur relative to the weight of fuel.

The sulfur content of diesel fuels has now been or has been reduced in many countries for environmental reasons, ie to reduce sulfur dioxide emissions. Thus, the sulfur content of the heating oil and diet: • »: 30 is nearing the maximum CEC value of · · ·: 0.02% by weight, and in the second stage diesel · ···. the maximum concentration of the ingredients will be 0.05% by weight.

• · · A complete transition to a maximum of 0.05% by weight may be mandatory in 1996.

· «· 35 • · • · · · · · · 2

The process of producing low sulfur fuels reduces not only the sulfur content but also the content of other fuel components, such as polyaromatic and polar components. Reducing the concentration of one or more sulfur, 5 polyaromatic or polar components in the fuel causes a new problem with fuel use: the fuel's ability to lubricate the engine's injection system is reduced so that the engine's injection pump may fail while the engine is still relatively new. high pressure dispensers, line pumps and single syringes and sprayers. Such serious disadvantages result from wear, which is quite different from the wear due to corrosion described in GB-A-1505302.

15

As already pointed out, such a failure may occur while the engine is still relatively new; instead, the wear problems referred to in GB-A-1505302 occur later in the engine life. The problems caused by the use of low sulfur diesel fuels are described, for example, by D. Wei and H. Spikes, Wear, Vol. Ill No. 2, p. 217, 1986, and R. Caprotti, C. Bovington, W.

.T: Fowler and M. Taylor, SÄE paper 922183, SÄE fuels and lubes ,; meeting Oct. 1992, San Francisco, USA.

It has now been discovered that the above-mentioned low sulfur incineration plants. wear problems caused by their use can be reduced or eliminated by using certain additives in the fuel.

A first object of the present invention is a fuel oil composition having a higher proportion of liquid hydrocarbon middle distillate oil having a sulfur content of 0.2% by weight or less and a lower proportion of a carboxylic additive. * * ·. an ester of sylic acid and alcohol; the acid has 2 to 50 carbon atoms and the alcohol has one or more carbon atoms.

• · · 35 • * I · f • · · • · 3

Another object of the invention is to use a fuel oil composition as defined in the description of the first object of the invention as a fuel in a compression ignition (diesel) engine to limit the wear rate of the engine injection system 5 when the engine is running.

A third object of the invention is a method of using a compression ignition (diesel) engine using a fuel oil composition 10 as described in connection with the first aspect of the invention as fuel in the engine and thereby limiting the system's wear rate to the engine's injection.

The examples in this disclosure demonstrate the effectiveness of the additives of the invention in reducing wear when using the fuel oils of the invention.

Without wishing to be bound by any particular theory, we believe that the additive, when used in a compression-ignition internal combustion engine composition, can form at least partial single or multimolecular layers of additive on the surfaces of the injection system components, particularly, the jet pump surfaces. ; ; with each other, the composition being such that, compared to a composition in which this additive is not present, there is at least a reduction in wear, a reduction in friction, or an electric •! increase in contact resistance in any test, where two or more charged bodies are in relative motion under non-hydrodynamic lubrication conditions.

Features of the invention will now be described in more detail.

• i * i * i *

, ···. ADDITIVE

• * • * * • · · 35 As already mentioned, we believe that an additive, which may be * * 5 / ·· one additive or additive mixture, can form at least 4 partial layers on certain surfaces of the engine. This means that the resulting layer may not completely cover the contact surface. Thus, it can cover only part of the contact surface, for example 10% or more or 50% or 5%. The formation of such layers and the extent to which they cover the contact surface can be demonstrated, for example, by measuring electrical contact resistance or electrical capacitance.

Examples of tests that can demonstrate at least either wear reduction, friction reduction, or increased electrical contact resistance according to the present invention include the BOCLE (Ball On Cylinder Lubricant Evaluator Test) and the HPPR (High Frequency Reciprocating Rig Test), which are referred to below. .

15

Next, the acids, alcohols, and barriers are discussed in more detail.

(i) Acid The acid form from which the ester is derived may be mono- or polycarboxylic acid such as aliphatic, saturated or unsaturated, straight or branched, mono- and dicarboxylic acid. *:. recommended. The acid can be represented by the general formula · #; ·! ·. 25 R '(COOH) "

* I

• x · i :: * 11. * where x is an integer and is 1 or more such as 1-4, and R '· · · is a hydrocarbyl group containing 2 to 50 carbon atoms and is a monovalent or polyvalent x by value. -COOH groups, • Φ ·. · · 30 when more than one is present, possibly · ♦ · V · as substituents on different carbon atoms.

"Hydrocarbyl" refers to a group containing carbon and hydrogen and is attached to the rest of the molecule via a carbon atom. It may be straight or branched and the chain may be interrupted by one or more heteroatoms such as 0, S, N or P, it may be saturated or unsaturated, aliphatic, alicyclic or aromatic, including heterocyclic, and substituted or unsubstituted. unsubstituted. Preferably, when the acid is a monocarboxylic hydrocarbyl group, it should be an alkyl-5 group or an alkenyl group containing 10 - (e.g. 12) 30 carbon atoms, i.e., the acid is saturated or unsaturated. The alkenyl group may have one or more double bonds, for example 1, 2 or 3. Examples of saturated carboxylic acids are those having 10 to 22 carbon atoms such as capric, lauric, myristic, palmitic and docosanic acids, and examples of unsaturated acids carboxylic acids are those having 10-22 carbon atoms such as olein, elaidin, palmitolein, petroselin, ricoline, ele-stearin, linoleic, linolenic, eicosanol, galolene-15 nic, erucic and hypogeiinihappo. When the acid is polycarboxyl containing, for example, 2 to 4 carboxy groups, the hydrocarbyl group should preferably be substituted or unsubstituted polymethylene.

20 (ii) Alcohol

The alcohol from which the ester is derived may be a mono- or polyhydroxy alcohol such as trihydroxy alcohol. Alcohol can be presented. *! . master plan: • · · * ·· * «: *! *. R 2 (OH) y · · · · · · · · * · * where * y is an integer of 1 or more and R 2 is • → 4 a hydrocarbyl group containing 1 or more carbon atoms, for example at most 10 lattice atoms, which are mono- • ·: 30 or plural according to y, and -OH groups when more than one ··· ί, ί · may be present, ···, on different carbon atoms.

· · · * · *: "*" Hydrocarbyl "has the same meaning as given above with respect to acid · 35. In alcohol, the hydrocarbyl group should preferably be: an alkyl group or a substituted or unsubstituted polymethylene group. containing from 1 to 6 carbon atoms such as methyl, ethyl, propyl and butyl alcohol.

Examples of polyhydric alcohols are aliphatic, saturated or unsaturated, straight or branched chain alcohols having from 2 to 10, preferably from 2 to 6, more preferably from 2 to 4, hydroxy groups and containing from 2 to 90, preferably from 2 to 30, more preferably 2 to 5, 12, most preferably 2-5 carbon atoms per molecule.

More specific examples of polyhydric alcohols include glycol and diol, and trivalent alcohols such as glycerol.

(iii) Esters The esters may be used alone or in admixture with one or more esters and may consist solely of carbon, hydrogen and oxygen. Preferably, the ester should have a molecular weight of 200 or more, or at least 10 carbon atoms, or both.

20

Examples of suitable esters are the lower. *} '· Alkyl esters such as methyl esters mentioned above as examples. subsidies of saturated or unsaturated monohydric acids. Such esters can be obtained, for example, from sapo - .. *! 25 by nification or esterification of natural * plants or animals of animal origin; fats or oils or by transesterification with: :: ··· · aliphatic alcohols.

♦ · «« t »• · ♦«

Examples of suitable esters of polyhydric alcohols, · ·: 3 °, are those in which all the hydroxy groups are it *: esterified, those in which not all hydroxy groups are esterified and mixtures thereof. Specific examples include esters prepared from trivalent alcohols and i:.

* '* of one or more of the above-mentioned saturated or unsaturated carboxylic acids, for example, glycerol monoesters or glycerol diesters, e.g., glycerol monooleate, glycerol dioleate or glycerol monostearate. Such polyvalent esters may be prepared by esterification according to the prior art and / or may be commercially available.

5

The ester may have one or more free hydroxy groups. FUEL OIL

The sulfur content should preferably be 0.05% by weight or less, for example 0.01% by weight or less, and may be as low as 0.005% by weight or 0.0001% by weight or less. The prior art describes methods for reducing the sulfur content of hydrocarbon distillate fuels, such as solvent extraction, sulfuric acid treatment and hydrodesulfurization.

"Tricyclic aromatic" means a solid system in which three aromatic rings are attached to each other. Preferably, the fuel should contain less than 1% by weight of such component 20.

* ί \ Examples of "polar components" are, for example, i / ·, those containing O, S or N, and the ester and alcohol * Y lit.

«V · · 1 25 I I j * \ The abovementioned wear problem has been found to develop t · 2“ · · 'the worse the smaller the polar component pi-V; content; by way of example, concentrations of less than 250 ppm, for example less than 200 ppm, are particularly bad, especially in fuels with a polar component: T: 170 ppm or 130 ppm. Such concentrations of polar components can easily be measured by high-pressure * · ·

I., by means of techno-chromatography, also called HPLC

J 1; · 1 (High Pressure Liquid Chromatography).

»· · S: 35 4» «·« «f» 1 · 2 · 8

The middle distillate fuel oils to which this invention can be applied will typically boil in the range of about 100 to about 500 ° C, e.g., about 150 to about 400 ° C. The fuel oil may comprise air distillates or vacuum distillates or cracked gas oil or as a blend in any proportion with straight and / or catalytically cracked distillates. The most common crude distillates are kerosene, kerosene, diesel engine oil, heating oil and heavy fuel oils. For the purposes of the present invention, diesel engine oils are most preferred for the above reasons. The heating oil 10 may be a straight air distillate or may contain some, e.g., up to 35% by weight of vacuum gas oil or cracked gas oils, or both.

The concentration of the additive according to the invention in the fuel oil may be up to 250,000 ppm, for example up to 10,000 ppm such as 1 to less than 1000 ppm (active ingredient) by weight percent of fuel, preferably 10-500 ppm, more preferably 10-200 ppm.

The additive may be incorporated into the fuel oil according to the prior art. The additive can readily be included as a concentrate containing the additive and a suitable oil in the fuel oil. carrier medium, additive dispersed in liquid », ··. medium. Such concentrates may preferably contain from 3 to 75% by weight, more preferably from 3 to 60% by weight, most preferably 10 to 50% by weight of an additive, more preferably. * 'As a solution in oil. Examples of carrier liquids are orphan organic solvents such as hydrocarbon solvents, e.g. such as 2-butoxyethanol. Parent: Of course, the Tj liquid must be selected according to its compatibility with the additive and fuel.

• · ·

β '·! ADDITIVES AT THE SAME TIME

The additives of the invention may be used alone or as mixtures of one or more additives. They may also be used in combination with one or more other prior art adjuvants, for example: detergents, antioxidants (to prevent fuel degradation), corrosion inhibitors, anti-fog agents, demulsifiers, metal deactivators, waxes, , co-solvents, sealant mixers, and medium distillate cold flow improvers.

EXAMPLES

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

Additives: D: glycerol monooleate 15 E: diisodecyl adipate

Fuels: The fuels used were designated I and II and were diesel fuels with the following characteristics: 20 ... I Sulfur content <o, o% (wt / wt) * · * ·] 'Aromatic content <l% (wt / wt) ) V * Cetane number 55.2-56.1 liters * 25 CFPPT (Cold Filter Plugging Point Temperature) -36 ”c

: *: 95% boiling point 273 ° C

Sulfur content <0.01% (wt / wt)

The aromatic content was not measured; . ·. 30 Cetane number not measured • · ·

CFPPT -41 ° C

• · ·

*. 95% boiling point 263 ° C

·· * • · · ♦ · ·

Experiments: • · · 35 Additives D and E were dissolved in fuels I and II and obtained • · I * '. the composition was tested by: 10 ° BOCLE (Ball On Cylinder Lubricant Evaluator) described in Friction and wear devices, 2nd Ed., p.

280, American Society of Lubrication Engineers, Park Ridge 111, USA, and F. Tao and J. Appledorn, ASLE trans. 11: 345-352, 5 1986, and by the HFFR (High Frequency Reciprocating Rig) test described in D. Wei and H. Spikes, Wear, Vol. 2, pp. 217, 1986, and R. Caprotti, C. Bovington, W. Fowler and M. Taylor, SAE paper 922183, SAE fuels and lubes, meeting Oct.

10, 1991, San Francisco, USA.

Both tests are known as fuel lubricity tests.

15 Results:

The results are shown in the tables below.

(A) The results of the BOCLE test 20 are given in the diameters of the wear figures. Thus, a lower value indicates less wear and tear than a higher value.

... ^ All tests were performed at ambient temperature.

• · · • · • 1 2 3 1 * · 1 1 Fuel I: m • · · 25 • · · • 1 · I. . ___ • · ^ || 1 'i I \ Additive Additive content Result • · ·:; i .: (ppm; wt / wt) (μια) * · · ........... .....

* Base Fuel - 852 * · •: .i ί D 200 505 • »· ......... .1 i, l lii -1::: 30 ♦» • · · • · * · «· ·· • 1 • · ··· · 2 • · 3 • · • · · iR • · 11

Fuel II:

Additive Additive content Result (% by weight) (μπι)

Base Fuel - 700 5 D 50 570 D 100 500 D 200 520 D 500 480 10 _D__1000__430_ (B) HFRR Test: 15 These results are also expressed as Diameter Wear Values. The experiments were performed at the indicated temperatures. In fuel I, the concentration of additive D was 200 ppm (wt / wt) and the content of additive E was 10,000 ppm. In fuel II, the concentration of additive D is indicated in brackets.

20 aaa • · aaa

. ·; . Fuel I

• a a a a a «aa

.. *! 20 ° C 25 ° C 60 ° C

a a a a a a. ..........

a a I I | Β ··· .Ί1ιΤ.Ι "ι'ι'ι11'ι'ι '", TV' ^ SSSS ^ SOSSSSISSSSS ^^ S ^^^ B

:. ·. 25 Additive Friction- Wear- Wear- Friction- Wear- • a a. ···. coefficient career career coefficient career a · * Through- Through- Through- Through. . measure measure measure · · · :: i .: (Mm) (μια) (μη)

• * a «....... ^ - n I I

Base 0.59 540 576 0.72 590 a a a a a a a a a J ***: D 0.19 240 180 0.19 160 aaa a aaa a a *: · *. 30 IS__ 344 442 a a a 'a a 12

Fuel II

20 ° C 60 ° C

Additive Friction- Wear- Friction- Wear-coefficient groove coefficient groove Diameter (mm) (mm)

Base 0.60 600 0.75 630 D (10ppm) 0.95 530 0.83 570 D (50ppm) 0.55 580 0.58 590 10 D (100ppm) 0.41 530 0.39 560 D (ISOppm) 0.21 0 0.22 240 D (200ppm) 0.23 <20 0.23 250 D (100ppm) __ 0.22__0__0.23 250 15

The results show that lubricity improves with the use of additives D and E.

· »1 • i« i «i« i «i« i «i« i «i« i «i« i «i« i «i« i «i« 1 «II1 * · i« 1 «• i *. 1 ♦ • · • I I I I I I tt «* · 1 1 1 1 1 1 1 1 1:: • · f * ♦ · 1 · • 1 1 1 1 1 t ·» • · · • ·

Claims (18)

1. Fuel oil composition, the greater part of which is diesel fuel with a sulfur content of 0.2% by weight or less and lesser part is an additive containing carboxylic acid and alcohol esters, characterized in that the acid comprises from 2 to 50 carbon atoms and the alcohol one or more carbon atoms, with the proviso that: (A) the additive is not a polyhydric acid or an ester of a polyhydric acid or a partial ester of a polyhydric alcohol *. * and a fatty acid, nor «* · ··« (B) The additive comprises a reaction product of dicarboxylic acid and oil-insoluble glycol, and ··· • · • ♦ * In addition, the content of said additive in the fuel oil is 100-200 ppm weight percent active constituents of the weight of said fuel oil. . ···. 3 0 • ·, ·. Composition according to claim 1, characterized in that the weight content is 0.05% by weight or less. Composition according to claim 2, characterized in that the sulfur content is 0.01% by weight or less. • · • e Composition according to any of the preceding claims, characterized in that the acid from which the ester is derived has the general formula R'COOH, in which R 'is a hydrocarbyl group. 5 Composition according to claim 4, characterized in that the acid comprises 10 to 30 carbon atoms and the acid is saturated or unsaturated with 1-3 double bonds in the alkenyl group. Composition according to claim 5, characterized in that the acid comprises 12-22 carbon atoms. Composition according to any one of claims 1-3, characterized in that the acid is a polycarboxylic acid of the formula R 2 (COOH) x, in which x is an integer of 2-4 and R 2 is a substituted or unsubstituted polymethylene group. Composition according to claim 7, characterized in that the acid is dicarboxylic acid. 20 # ... 9. Composition according to any of the preceding claims, characterized in that the alcohol is alkyl alcohol having 1-6 carbon atoms. • «« • # I Composition according to claim 12, characterized in that the alcohol is glycerol. Composition according to claim 13, characterized in that the ester 5 is glycerol monoleate. Use of a fuel oil according to any of the preceding claims as fuel in a diesel engine to control the rate of wear in the engine's injection system where the engine is in operation. 10 A method of operating a compression-ignition engine using a fuel oil composition as claimed in the preceding claim as fuel in the engine to control the rate of wear in the engine's injection system. 15 Use according to claim 15, characterized in that the wear increases in the injection pump of the engine. The method according to claim 16, characterized in that the wear 20 rises in the injection pump of the engine. • · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 1 · · · · · · · · · · · 1 · »·· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·