US3920414A

US3920414A - Crude oils containing nitrogen dispersants and alkoxylated ashless surfactants usable as diesel fuels

Info

Publication number: US3920414A
Application number: US301612A
Authority: US
Inventors: David E Steere; Thorkild F Lonstrup
Original assignee: Exxon Research and Engineering Co
Current assignee: ExxonMobil Technology and Engineering Co
Priority date: 1972-10-27
Filing date: 1972-10-27
Publication date: 1975-11-18
Anticipated expiration: 1992-11-18
Also published as: CA1016358A

Abstract

Synthetic or natural crude oils having low inorganic salt and sulfur contents and which contain a polymeric dispersant and an alkoxylated ashless surfactant are useful as fuels for heavy duty diesel engines. The ashless dispersants of this invention can be characterized as having long carbon chains joined to a polar oxygen-containing or nitrogen-containing moiety. The surface active agents of this invention have a polar moiety such as an acidic or phenolic group alkoxylated with an alkylene oxide. The crude oils used in this invention have a sulfur content of 1 wt. % or less and an inorganic salt content below 3 pounds per thousand barrels of crude oil. The crude oil can be of paraffinic, asphaltic or a mixed type or a synthetic crude isolated from oil or tar sands.

Description

United States Patent Steere et CRUDE OILS CONTAINING NITROGEN DIESEL FUELS [75] Inventors: David E. Steere, Sarnia, Canada; Thorkild F. Lonstrup, Goring on Thames, England [73] Assignec: Exxon Research & Engineering Co.,

Linden, NJ

[22] Filed: Oct. 27, 1972 [21] Appl. No.: 301,612

[52] US. Cl. 44/66; 44/71; 44/72 [51} Int. Cl. ClOL l/24 [58] Field of Search 44/66. 71, 72; 252/DIG. 1, 252/351, 353

[56] References Cited UNITED STATES PATENTS 3,219.666 11/1965 Norman et al 252/515 A $367,943 2/1968 Miller et al. 44/71 3,381,022 4/1968 LeSuer 260/404.8 1630.953 12/197] Simon et a] 252/351 3.658.495 4/1972 Dorer. Jr. 44/71 3,658.707 4/1972 Delafield et al. 44/71 1451 Nov. 18, 1975 FOREIGN PATENTS OR APPLICATIONS 830,864 3/1960 United Kingdom 252/1310. 1

Primary Examiner-Daniel E. Wyman Assistant ExaminerY. Harris Smith Attorney, Agent, or Firm-Daniel H. Hall; Byron O Dimmick ABSIRACT Synthetic or natural crude oils having low inorganic salt and sulfur contents and which contain a polymeric dispersant and an alkoxylated ashless surfactant are useful as fuels for heavy duty diesel engines. The ash less dispersants of this invention can be characterized as having long carbon chains joined to a polar oxygencontaining or nitrogen-containing moiety. The surface active agents of this invention have a polar moiety such as an acidic or phenolic group alkoxylated with an alkylene oxide. The crude oils used in this invention have a sulfur content of 1 wt. or less and an inorganic salt content below 3 pounds per thousand barrels of crude oil. The crude oil can be of paraffinic, asphaltic or a mixed type or a synthetic crude isolated from oil or tar sands.

7 Claims, No Drawings CRUDE OILS CONTAINING NITROGEN DISPERSANTS AND ALKOXYLATED ASHLESS SURFACTANTS USABLE AS DIESEL FUELS FIELD OF THE INVENTION This invention relates to crude oil compositions of low sulfur and inorganic salt content containing a dispersant and a surfactant additive, both of which are H 1 DESCRIPTION OF THE PRIOR ART Recently, it was discovered that naturally occurring or synthetic crude oils containing low sulfur and inorganic salt contents can be made usable as fuels for diesel engines by the addition to them of a dispersant selected from the group consisting of overbased alkaline earth metal sulfonates and alkylene polyamine condensation products such as some of the dispersants of the present invention. This invention was disclosed in U.S. Pat. No. 3,594,137.

The present invention represents an improvement over that invention in that it has now been found that it is possible to omit any ash-forming material from the crude oil and still obtain a fuel useful for operation of a diesel engine.

The above-noted U.S. Pat. No. 3,594,137 taught that the best results are obtained by using a combination of an ash'forming sulfonate with an ashless dispersant. It has now been found that the combination of an ashless dispersant with an ashless alkoxylated surfactant is similarly effective. Furthermore, the combination of the present invention, being totally ashless, contributes no solid particles to the environment upon combustion.

SUMMARY OF THE INVENTION It has now been found that crude oils of low sulfur and inorganic salt content can be made into fuels for diesel engines by combining them with an ashless dispersant and an ashless alkoxylated surfactant. The dispersants of the present invention have long hydrocarbon chains attached to a polar moiety and the ashless surfactants of the present invention are the reaction products of an alkylene oxide with an acidic organic material such as a carboxylic acid, an alkyl phenol or a hydrocarbon sulfonic acid.

Attempts have been made in the past to employ crude oils as fuels for compression engines such as heavy duty diesel engines. The incentive for such attempts has been one of economy. Unfortunately, such attempts in the past have shown poor results because of the resulting corrosion problems and the formation of high carbonaceous deposits in the engines. These deposits adversely affect the operation of the fuel injectors and lead to excessive fuel consumption. In addition. the attempted use of such crude oils as diesel fuels gave a diesel lubricating oil useful life of the order of 10,000 miles when used in a railroad diesel engine vs. an oil life in excess of 50,000 miles when conventional diesel fuel was used.

The principal reason for this short life of the diesel lubricating oil was that excessive sludge and soot deposits accumulated in the oil. These deposits were not removed by the customary oil filters used in connection with the operation of heavy duty diesel engines.

It was subsequently discovered that the principal reason for the excessive corrosion and carbon deposition pertaining to the fuel injectors and lack of general engine cleanliness was that the crude oils employed contained excessive amounts of inorganic salts, elemental sulfur and sulfur compounds which are naturally occurring in many crude oils. The effective removal of excessive inorganic salts from crude oils is a conventional process which has been practiced for many years and it was discovered that where the natural or synthetic crude oils contained more than about three pounds of inorganic salts per thousand barrels of oil, it was necessary to process such oils to bring the amount of inorganic salts below this figure in order for the crude oils to be satisfactorily employed as diesel fuels. The desalting techniques for accomplishing this are well known. See, for example, U.S. Pat. Nos. 2,074,183 and 2,l40,574. Essentially in these processes, crude oil is desalted by adding limited amounts of water to the crude, heating the crude oil under pressure to avoid loss of low boiling constituents, gently stirring the same to avoid emulsion formation and allowing the salts to settle. Decantation, centrifugation or filtering may then be employed to separate the salts from the crude oil and, of course, the remaining water containing the dissolved salts is separated in conventional manner, as, for example, by further settling and decantation. In general, the desalting operation involves washing the salts from the oil under such conditions that rapid separation of the water solution from the oil together with undissolved inorganic salts, as solids, can be effectively carried out.

It was also discovered that excessive amounts of sulfur and sulfur compounds, again naturally occurring in many crude oils as produced throughout the world, caused deleterious effects in the operation and maintenance of heavy duty diesel engines. It was, therefore, found necessary in order to successfully use desalted natural and synthetic crude oils as diesel fuels to additionally desulfurize or sweeten them to the point where the sulfur content, both free and chemically combined, was less than l.0 wt. 7r. Here again, processes for sweetening or desulfurizing oils are conventional and have been known for many years. Representative U.S. patents showing such processes are U.S. Pat. Nos. 607,017; 620,882; 1,654,58l and 1,608,339. The conventional desalting and sweetening operations form no part of the present invention.

British Pat. No. 1,124,611 discloses a conventional diesel fuel containing an ashless dispersant and an alkyl nitrate. Such conventional fuels are more highly refined and accordingly more expensive than the crude oil fuels of the present invention.

DETAILED DESCRIPTION OF THE INVENTION Crude Oils The crude oils which can be used in the practice of the present invention constitute all types of crude oils produced throughout the world. They can be of paraffinic, asphaltic or mixed types. They can be naturally occurring crude oils or those which have been isolated from oil sands and shale oil deposits. It is preferred, however, to use naturally occurring or synthetic crude oils derived from oil sands.

It has been found that crude oils containing appreciable amounts of aromatic constituents, and to some extent crude oils containing appreciable amounts of naphthenic constituents are less desirable than are the paraffinic, mixed crudes and asphaltic crudes. In general, the crude oils, treated or untreated, which meet the above-defined sulfur and salt specifications are suitable for direct use in undiluted or unaltered form if they have an API gravity of between about 25 and about 45 measured at 60F and if they have a viscosity of between about 35 and 250 SUS at l"F. In using the higher viscosity oils. preheating of the oil is oftentimes employed to lower its viscosity for ease of injection.

in general, these crudes will have atmospheric pressure equivalent distillation boiling ranges between about 160 and about l.lO0F. Many crudes will have far narrower boiling ranges, particularly the synthetic crude oils, a typical one having a final distillation end point of below 700F. Conventional diesel fuels have a distillation range between about 350 and about 650F, but naturally the crude oils will have appreciable amounts of components boiling below 350 and above 650F. This does not adversely affect the operation of diesel engines.

Typical specific crudes which may be employed are desalted Pembina crude from Canada and synthetic crude prepared from Athabasca tar sands of Canada, wherein a hydrogenation of the virgin and delayed coker gas oils is carried out. This last named material is light in color and resembles a distillate fuel and is only slightly higher in its final boiling point than that of conventional diesel fuels although it contains an appreciable front end fraction with an initial boiling point slightly higher than that of conventional diesel fuel. Another synthetic type crude oil is that obtained and recovered from the distillation of oilcontaining shales. A representative material has an initial boiling point of about 430F and a final boiling point of about l,050F, an API gravity of l9 at 60F and a viscosity of 200 SUS at 100F. Other specific types of crudes which are advantageously employed include those from the Leduc field in Western Canada, the paraffinie crudes of Pennsylvania and the Middle East, the mixed base crude oils of the Mid Continent and the asphalt base crudes of the Gulf Coast and California.

The desalted and sweetened crude oils discussed above were tried as fuels for marine and railroad heavy duty diesel engines without any further treatments but they did not perform well. It was found that despite these pretreatments, unsatisfactory diesel lubricating oil life resulted and heavy fouling of the fuel injectors occurred. In these earlier tests in laboratory engines, it was necessary to change fuel injectors about every hours in order to avoid excessive injector fouling. The used oil life was relatively short. Heavy sludge and fuel soot were deposited in the lubricating oil. Additionally. the used oil clearly showed the result of the injector fouling because it had as much as 41% viscosity increase coupled with the aforementioned additional disadvantages.

It was found that a more successful operation of these heavy duty diesel engines. from an overall performance standpoint, could be accomplished if the injectors could be maintained relatively clear and free of carbonaceous deposits and ifthey could, of course, be free of injector corrosion. Surprisingly. the incorporation into the crude oil diesel fuel of relatively small amounts of either an ashforming dispersant or an ashless dispersant. or preferably both types, gave a surprising effect as to reduced fuel consumption, piston cleanliness, improved lubricating oil life and injector cleanliness. The overall freedom from complications in the operation and maintenance of heavy duty diesel engines using these additive-treated fuels was comparable to that attainable using conventional and regular diesel fuel. Similar improvements have now been realized using the totally ashless additive combination of the present invention at lesser concentrations than the aforementioned ash-containing additive combination. Dispersant Additives The dispersant additives of the present invention are characterized by having a long hydrocarbon chain, typically containing 40 to 250 carbon atoms per chain, attached to a polar organic moiety. These materials are ashless and sold commercially on the open market, principally as dispersants for automotive lubricating oils. Typical patents which disclose their preparation and use are US. Pat. Nos. 3,172,892 and 3,219,666.

A particularly useful class of dispersants for the present invention are those which contain nitrogen. These dispersants include mineral-oil-soluble salts, amides, imides and esters of monoand diearboxylic acids (and, where they exist, the corresponding acid anhydrides) and various amines or nitrogen-containing materials having amino nitrogen or heterocyclic nitrogen and at least one amido or hydroxy group capable of salt, amide, imide or ester formation. The diacids and anhydrides are preferably alkenyl substituted. These dispersants are characterized by a long chain hydrocarbon group or groups attached to the acid so that the acid contains a total of about 50 to 250 carbon atoms, said acid being attached to the amine either through salt. imide, amide or ester groups. Usually, these dispersants are made by condensing a monocarboxylic acid or a dicarboxylic acid, preferably a succinic acid producing material such as alkenyl succinic anhydride, with an amine or polyamine.

Monocarboxylic acid dispersants have been described in British Patent Specification No. 983,040. There, the high molecular weight monocarboxylic acids were derived from a polyolefin, such as polyisobutylene, by oxidation with nitric acid or oxygen, or by addition of halogen to the polyolefin followed by hydrolysis and oxidation. The monocarboxylic acid may also be obtained by oxidizing a monohydric alcohol with potassium permanganate or by reacting a halogenated polyolefin with a ketone.

Another method is taught in Belgian Pat. No. 658.236 where polymers of C to C monoolefins, e.g. polypropylene or polyisobutylene, are halogenated, e.g. chlorinated, and then condensed with an alpha. beta-unsaturated monocarboxylic acid of from 3 to 8, preferably 3 to 4, carbon atoms. e.g. acrylic acid. alpha-methacrylic acid, crotonic acid. or isocrotonic acid, tiglic acid (alpha-methylcrotonic acid), angelic acid (alpha-methylisocrotonic acid), sorbic acid, cinnamic acid, etc. Esters of such acids, e.g. ethyl methacrylate, may be employed if desired in place of the free acid.

The most commonly used dicarboxylic acid is alkenyl succinic anhydride wherein the alkenyl group contains about 60 to 250 carbon atoms.

Primarily because of its ready availability and low cost, the hydrocarbon portion of the monoor dicarboxylic acid is preferably derived from a polymer of a C to C monoolefin, said polymer generally having a molecular weight of about 700 to 3.000, e.g. about 700 to 1,300. Particularly preferred is polyisobutylene.

Polyalkyleneamines are usually the amines used to make the dispersant. These polyalkylencamines include those represented by the general formula H,N(CH,).,-INH(CH,),,l,,,-NH(CH,1,,NH wherein n is 2 or 3, and m is to l0. Examples of such polyalkyleneamines include diethylene triaminc, tetraethylene pentamine, oetaethylene nonamine, tetrapropylene pentamine, as well as various cyclic polyalkyleneamines. Mixtures of these amines can also be used.

Dispersants formed by reacting about equal molar amounts of polyisobutenyl succinic anhydride and a tetructhylenc pentamine are described in U.S. Pat. No. 3,202,678.

Similar dispersants, but made by reacting a molar amount of alkenyl succinic anhydride with about two molar amounts of alkenyl suceinic anhydride with about two molar amounts of polyalkyleneamincs, are described in U.S. Pat. No. 3,154,560. Other dispersants, using still other molar ratios of alkenyl suceinic anhydride and polyalkyleneamines are described in U.S. Pat. No. 3,172,892. Still other dispersants of alkenyl suceinic anhydride with other amines are described in U.S. Pat. Nos. 3,024,195 and 3,024,237 (piperazine amines); and 3,219,666. An ester derivative is taught in Belgian Pat. No. 662,875 where N-alkyl morpholinone esters, e.g. N-(Z-hydroxyethyl)-2-morpholinone, are formed by reaction with polyisobutylene succinic anhydride. The prior art also teaches that the alkenyl succinie polyamine type dispersants can be further modified by reacting a fatty acid, having from 2 to 22 carbon atoms.

e.g. acetic acid, with the reaction product of the alkenyl succinic anhydride and polyamine (see U.S. Pat. No. 3,2l6,936).

For the purposes of the present invention any of the nitrogen-containing dispersants described in any of the aforementioned patents can be used in carrying out the present invention.

Also useful as dispersants in the present invention are those materials which are made by condensation of the above-described organic acids with a polyol such as pentaerythritol, glycol, etc. Such dispersants are described in U.S. Pat. Nos. 3,381,022, 3,522,179 and 3,542,678.

Ashless Alkoxylated Surfactants The ashless surfactants used in the present invention are generally made by the reaction of an alkylene oxide such as ethylene or propylene oxide with an acidic organic material. Among such acidic organic materials are fatty acids having 2 to 30, preferably 8 to carbon atoms, phenols and alkylated phenols having 6 to 30, preferably 12 to 20 carbon atoms and synthetic and pe troleum sulfonic acids having 2 to 30, preferably 8 to 20 carbon atoms.

The alkoxylated fatty-acid-derived surfactants used in the present invention have the general formula:

wherein R is a C to C preferably C to C,.,, aliphatic group. A is an oxygen or sulfur atom. n and m are each numbers from 0 to l4 and the sum ofn m is between 2 and 14.

The above-noted alkoxylated organic acid materials generally contain from 2 to 14 molar units derived from 6 an alkylene oxide, preferably 5 to [2 molar units. Specific examples of the fatty acids used to make the surfactants of this invention include the following:

Caprylic Stearie Capric Oleic Laurie [.inoleic Myristic Gadoleie Palmitic Cetoleie. etc.

The phenols which can be condensed with the abovenoted aklylene oxides to form the ashless surfactants of the present invention have the following general formula:

wherein A is an oxygen or sulfur atom, preferably an oxygen atom; R is a hydrocarbyl group, preferably an aliphatic group, containing 1 to 20 carbon atoms; most preferably R is an alkyl group containing 6 to 14 carbon atoms. Among the alkyl groups which R can represent are the following:

methyl n-propyl isobutyl tertiary butyl n-hexyl Z'ethyI hexyl n-dodecyl iso-dodeeyl n-oetadecyl. etc.

The resultant alkoxylated phenols have the general formula:

HZI

wherein A and R' are as defined above, n and m are each numbers from O to 14 and the sum of n' m' is between about 6 and [4.

Many of the above-described alkoxylated alkyl phenols and alkoxylated fatty acids are commercially available under a wide variety of trade names. Many of these are tabulated in Kirk-Othmer Encyclopedia of Chemical Technology, Volume 19, Second Edition, Interscience Publishers, New York. I969, pages 534 to 535 and pages 542 to 543.

The ashless surfactants of the present invention can also be made by condensing the above-noted alkylene oxides with sulfonic acids.

The hydrocarbon sulfonic acids suitable for use as precursors to the alkoxylated sulfonic acids of this invention include oil soluble petroleum sulfonie acids and synthetic alkaryl sulfonic acids, particularly those having molecular weights of from about 200 to 500. These sulfonic acids can be produced by sulfonation of petroleum stocks or synthetic alkyl aromatic compounds, such as alkyl-substituted benzenes or napthalenes. wherein the alkyl groups attached to the aromatic ring contain at least about 8 carbon atoms, the wax-substituted benzenes and naphthalenes being par ticularly preferred.

The petroleum sulfonic acids, also known as sour oils, are those obtained in the treatment of petroleum oils. particularly refined or semirefined oils. with concentrated or fuming sulfuric acid and which remain in the oil after settling out of sludge. These sulfonic acids may be represented by the general formula where R" is one or more alkyl, alkaryl or aralkyl groups, the aromatic nucleus is a single or condensed ring or partially hydrogenated ring, and y is to 4.

The preferred alkoxylated sulfonic acids of this invention can be characterized by the general formula:

wherein R is a C to C preferably C to C hydrocarbyl group, n" and m" are each numbers between 0 and 16, the sum of n" m" is between about 6 and i6, and y is 0 to 4.

In the diesel fuels of the present invention, the abovedescribed ashless dispersant and ashless surfactant are each used in the amount of about 0.01 to about l.0 wt. preferably 0.02 to 0.2 wt. based on the crude oil. A light solvent oil is usually included with the additives to aid mixing. A typical solvent oil is a solvent extracted paraffinie oil having a distillation range of about 310 to 350F and a viscosity at 25C of 0.779. Generally, heating is not required to effect solution in the solvent oil.

The above-noted additives are combined with the crude oils generally by mixing them together with mild agitation and/or beating them to a temperature of 50 to l50F. preferably 75 to l00F for about 0.5 to 3.0 hours. The dispersant and surfactant of the present invention are used in to 0.! preferably i to 0.3, parts by weight of dispersant per part of surfactant by weight. The combination of dispersant and surfactant can either be used to formulate a concentrate which is then added to the fuel or it can be added directly to form a fuel composition. If used in a concentrate. the combination of dispersanat and surfactant constitutes 5 to I00 wt. of the concentrate. The remainder of the lit concentrate can be composed of an inert hydrocarbonsoluble diluent such as a lube oil. diesel oil fraction or light solvent oil being in the range of 250 to 400F. if added to a crude oil to form a diesel fuel. the dispersantsurfactant concentrate combination is added in the amount of 0.01 to L0 parts by weight per hundred parts of oil.

EXAMPLES To demonstrate the effectiveness of the additive combination of the present invention, a series of comparative engine test runss were made in a laboratory diesel engine. These tests involved the use of a Buda single cylinder diesel engine Model BD-38. Each test was carried out for a period of 200 hours at an engine speed of about 1,500 rpm. The injector timing was set at l7.5 BTDC (before top dead center). the power output was about 6 brake horsepower. the crankcase lubricating oil temperature was maintained at about 240F.i2F.. and the water jacket temperature was maintained at about l90F.i2F. The exhaust gas temperature varied between about 800 and about 850F. The oil pressure was at 33 pounds per square inch and the air intake pressure at about 3 pounds per square inch.

The following additives. in the concentrations noted in the following table, were evaluated in crude oil according to the above-described procedure:

Additive A was a prior art. ash-containing additive, such as described in US. Pat. No. 3.594.137. Specifically the additive was an overbased barium sulfonate derived from propylene-alkylated benzene sulfonic acids having a minimum total base number of 59 in a lubricating oil concentrate (about to 48 wt. 71 active ingredient). About one-half of the total barium present was colloidal barium carbonate. The total barium content was between l4.3 and 14.9 wt.

Dispersant D-l. an ashless dispersant, was the con densation product of 2.8 moles of polyisobutenyl succinic anhydride with 1 mole oftetraethylene pentamine in a lubricating oil concentrate containing 70% of the active ingredient.

Surfactant S-l. an ethoxylated alkenylphenol. was a nonyl phenol ethoxylated with an average of 6 to 9 moles of ethylene oxide and sold commercially under the name of lgepal CO-530.

The crude oil used in these tests was the same as that described in US. Pat. No. 3.594.137 and had the following properties: API gravity at 60F. 37.4; sulfur content. 0.26 wt. 7%; viscosity at l00F. 4i SUS; and salt content. 2.0 lbs/I000 bbls.

EFFECT OF ADDITIVES ON INJECTOR FOULlNG Dispersant D-l Additive in Crude Oil 507: Surfactant Sl Additive A Dispersant D-l Surfactant S-l Nil WI. 1 additive (total) 0.05 0.l U.l 0.05 Crude Oil Consumption lbs/Z00 hr 707 700 690 693 790 injector Fouling No. of injectors replaced 0 2 3 3 3 Total carbon deposits On injectors and precombustion chamber. gm L03 0.48 2.33 2.38 .36 Used Oil Condition Vise inc i 32 44 46 I3 227 Pentane insol it 3.) 5.0 3.4 [.3 [3,4

Ash forming prior art components Comment Invention material of invention base oil The data in the first column of the table demonstrate that a total of 0.05% of the dispersant-surfactant combination of the present invention reduces to zero the number of injectors which had to be replaced because of fouling. In contrast, the second column shows that two injectors had to be replaced when using the ashforming additive of the U.S. Pat. No. 3,594,137, even though the concentration was twice as great. Although the carbon deposits with the ash-forming additive were less, this is to be expected since twice as much additive was used. ln other respects the two formulations performed in a very similar fashion.

The data in the third and fourth columns show that neither the dispersant nor the ashless surfactant by itself in concentrations equivalent to or greater than that of the first column led to satisfactory results. In both these cases. three fuel injectors were fouled to the point requiring replacement.

Furthermore, a comparison of the data in the first column with those in the third and fourth columns is clear evidence of the synergistic interaction of the dispersant and surfactant in the formulations of the present invention. This invention formulation (first col umn) performed better than an equivalent amount of surfactant S-l or twice the amount of dispersant D-l What is claimed is:

I. An oil composition suitable for use as a fuel in a compression engine comprised of a major amount of a synthetic or natural crude oil containing less than I wt. sulfur and less than 3.0 pounds of inorganic salts per l000 barrels of oil, having an API gravity of about 25 to 45 at 60F, a distillation boiling range of 160 to l IF and minor but engine deposit reducing amounts of:

a. one or more ashless dispersants selected from the group consisting of alkylene polyamine or polyol condensation products of: (i) alkenyl substituted dicarboxylic acids or their anhydrides or (ii) alkenyl substituted monocarboxylic acids or their anhydrides, said alkenyl group containing between about 50 and 250 carbon atoms; and i b. one or more ashless, oil soluble surfactants selected from the group consisting of: (i) alkoxylated fatty acid esters of the general formula:

wherein R is a C to C aliphatic group, A is an oxygen or sulfur atom, n and m are each numbers from 0 to 14 and the sum of n m is between 2 to l4; (ii) an alkoxylated alkyl phenol of the general formula:

wherein A is as defined above, R is a C to C alkyl group, n and m are each numbers from O to 14 and the sum ofn' m is between about 6 and I4; and (iii) alkoxylated sulfonic acids of the general formula:

wherein R" is a C to C hydrocarbyl group, n" and m" are each numbers between 0 and 16, the sum of n" m" is between about 6 and I6, and y is 0 to 4.

2. An oil composition as claimed in claim 1 wherein said ashless dispersant is a polyalkylene amine condensation product of said all-tenyl substituted dicarboxylic acid or anhydride.

3. An oil composition as claimed in claim 2 wherein the ashless surfactant is said alkoxylated alkyl phenol or said alkoxylated fatty acid.

4. An oil composition as claimed in claim 1 wherein the ashless surfactant is said alkoxylated alkyl phenol or said alkoxylated fatty acid.

5. An oil composition as claimed in claim 1 wherein said crude oil is a synthetic crude oil derived from tar sands.

6. An oil composition as claimed in claim 1 wherein said ashless dispersant is the condensation product of tetraethylene pentamine with isobutenyl succinic anhydride and said surfactant is said alkoxylated phenol wherein n is between 6 and 9, m is 0 and R is between C5 to C10.

7. A process for running a heavy duty diesel engine having a fuel injector which comprises running said engine while fueled with the crude oil composition defined by elaim l.

Claims

1. AN OIL COMPOSITION SUITABLE FOR USE AS A FUEL IN A COMPRESSION ENGINE COMPRISED OF A MAJOR AMOUNT OF SYNTHETIC OR NATURAL CRUDE OIL CONTAINING LESS THAN 1 WT.% SULFUR AND LESS THAN 3.0 POUNDS OF INORGANIC SALTS PER 1000 BARRELS OF OIL, HAVING AN API GRAVITY OF ABOUT 25* TO 45* AT 60*F, A DISTILLATION BOILING RANGE OF 160* TO 1100*F AND MINOR BUT ENGINE DEPOSIT REDUCING AMOUNTS OF: A. ONE OR MORE ASHLESS DISPERSANTS SELECTED FROM THE GROUP CONSISTING OF ALKYLENE POLYAMINE OR POLYOL CONDENSATION PRODUCTS OF: (I) ALKENYL SUBSTITUTED DICARBOXYLIC ACIDS OF THEIR ANHYDRIDES OR (II) ALKENYL SUBSTITUTED MONOCARBOXYLIC ACIDS OR THEIR ANHYDRIDES, SAID ALKENYL GROUP CONTAINING BETWEEN ABOUT 50 AND 250 CARBON ATOMS; AND B. ONE OR MORE ASHLESS, OIL SOLUBLE SURFACTANTS SELECTED FROM THE GROUP CONSISTING OF: (I) ALKOXYLATED FATTY ACID ESTERS OF THE GENERAL FORMULA:

2. An oil composition as claimed in claim 1 wherein said ashless dispersant is a polyalkylene amine condensation product of said alkenyl substituted dicarboxylic acid or anhydride.

6. An oil composition as claimed in claiM 1 wherein said ashless dispersant is the condensation product of tetraethylene pentamine with isobutenyl succinic anhydride and said surfactant is said alkoxylated phenol wherein n'' is between 6 and 9, m'' is 0 and R'' is between C6 to C10.

7. A process for running a heavy duty diesel engine having a fuel injector which comprises running said engine while fueled with the crude oil composition defined by claim 1.