GB2435884A

GB2435884A - Ethylene/vinyl ester and phenolic resin fuel additive package

Info

Publication number: GB2435884A
Application number: GB0604651A
Authority: GB
Inventors: Robert Dryden Tack; Masahiro Dairaku
Original assignee: Infineum International Ltd
Current assignee: Infineum International Ltd
Priority date: 2006-03-09
Filing date: 2006-03-09
Publication date: 2007-09-12
Also published as: JP5178029B2; GB0604651D0; JP2007238945A

Abstract

A fuel oil composition comprises: <SL> <LI>(A) - a middle distillate fuel having a carbon residue > 0.1 % mass; <LI>(B) - one or more copolymers of ethylene and a vinyl ester having a C1-18 alkyl group; <LI>(C) - one or more phenolic resins having a molecular weight of 400 to 10 000 gmol<-1> </SL> Preferably the vinyl ester in (B) has the formula CH2=CR<1>00CR<2>; R<1> is H, CH3; R<2> is C1-4 alkyl. Preferably the phenolic resin (C) is an alkyl (p-hydroxybenzoate)-aldehyde condensation product. Preferably the composition also contains additive (D), an oil soluble polar nitrogen compound carrying one or more 1{, 2{ or 3{ hydrocarbylamines or quaternary hydrocarbyl-ammonium salts.

Description

FUEL OIL COMPOSITION

This invention relates to fuel oil compositions.

BACKGROUND OF THE INVENTION

Some middle distillate fuel oils are characterised by a carbon residue level that is higher than normal. Such a high carbon residue level may arise from addition of residual fuel oil to a middle distillate fuel oil and is done in order to denature the middle distillate fuel oil to render it unsuitable as a fuel for "on-the-road" motor vehicles. An example of such a denatured fuel oil is the fuel oil referred to as Fuel Oil A and found in Japan.

Fuel Oil A is used as a heating oil and therefore, in use, experiences slow-cooling conditions and needs to be able to pass through a mesh filter before being pumped to a burner. It is known to assist Fuel Oil A in meeting slow-cooling conditions by use of a middle distillate cold flow additive such as an ethylene-vinyl acetate copolymer.

However, a test has been introduced, as described in JP 10274616, that simulates the above-described use of Fuel Oil A as a healing oil. It is found to be difficult to achieve the necessary performance in the test (i.e. to achieve a "pass" at a low target temperature) using an ethylene-vinyl ester copolymer additive.

SUMMARY OF THE INVENTION

It is surprisingly found, as evidenced by the data in this specification, that improved performance in Fuel Oil A and similar oils in the test described above may be achieved by employing one or more polymers that are not wax crystal modifiers, namely low molecular weight phenolic resins in combination with one or more ethylene-vinyl ester copolymers.

Thus, in one aspect, the invention provides a fuel oil composition comprising (A) a middle distillate fuel oil, in a major amount, having a carbon residue, measured by ASTM Dl 89, of greater than 0.1% by mass; and the following additives, in respective minor amounts: (B) one or more copolymers of ethylene and a vinyl ester having an alkyl group containing from 1 to 18 carbon atoms; and (C) one or more phenolic resins having a molecular weight of 400 to 10,000 g/mol.

In this specification, the following words and expressions, if and when used, have the meanings as described below: "active ingredient" or "(a.i.)" refers to additive material that is not diluent or solvent; "comprising" or any cognate word specifies the presence of stated features, steps, or integers or components, but does not preclude the presence or addition of one or more other features, steps, integers, components or groups thereof; the expressions "consists of' or "consists essentially of' or cognates may be embraced within "comprises" or cognates, wherein "consists essentially of' permits inclusion of substances not materially affecting the characteristics of the composition to which it applies; "major amount" means in excess of 50 mass % of a composition; "minor amount" means less than 50 mass % of a composition; Also, it will be understood that various components used, essential as well as optional and customary, may react under conditions of formulation, storage or use and that the invention also provides the product obtainable or obtained as a result of any such reaction.

Further, it is understood that any upper and lower quantity, range and ratio limits set forth herein may be independently combined.

DETAILED DESCRIPTION OF THE INVENTION

The features of the invention relating where appropriate to each and all aspects of the invention will now be described in more detail as follows: MIDDLE DISTILLATE FUEL OIL (A) The middle-distillate fuel oil is a petroleum-based fuel oil generally boiling within the range of from 110 to 500, e.g. 150 to 400 or 170 to 370, C, according to ASTM D86. It may comprise atmospheric distillate or vacuum distillate, or a blend in any proportion of straight-run and thermally and/or catalytically cracked or hydrocracked distillate. Suitably, in the present invention, it is broad boiling, has a high final boiling point and has a moderate wax content (e.g. about 3% by mass at 10 degC below its cloud point).

As stated, the middle distillate fuel oil has a carbon residue of greater than 0.1% by mass. This is measured by the Conradson method, ASTM D189, in which a sample (lOg) of distillation bottoms is put in a tared crucible and subjected to destructive distillation, undergoing cracking and coking reactions during a fixed period of severe heating. After cooling and reweighing to calculate the amount remaining, the result is reported as percent Conradson carbon residue on 10% distillation residue.

The carbon residue may be in the range of 0.1 to 4, such as 0.2 to 2, preferably 0.2 to 1, % by mass. More particularly, the carbon residue is in the range of 0.2 to 0.5% by mass.

The above-mentioned carbon values may be achieved by mixing a middle distillate fuel oil with a residual fuel oil, sometimes referred to as residuum or resid. Residual fuel oil is the non-volatile portion of a crude oil resulting from distillation, which may be atmospheric or atmospheric followed by vacuum distillation.

Typically, the middle distillate fuel oil may contain from 2 to 10, such as 5 to 10, % by mass of residual fuel oil.

ADDITIVE (B) In additive (B), the vinyl ester preferably has the formula CH2=CR'OOCR2 (I) wherein R' represents a hydrogen atom or a methyl group and R2 represents an alkyl group having from 1 to 4 carbon atoms. More preferably, the vinyl ester is vinyl acetate.

The copolymer may comprise a terpolymer, being a polymer of ethylene, the vinyl ester and a second, different, vinyl ester that has an alkyl group containing from 5 to 15 carbon atoms.

The second vinyl ester, if employed, preferably has the formula CH2=CR300CR4 (II) wherein R3 represents a hydrogen atom or a methyl group and R4 represents an alkyl group having 5 or more, such as 5 to 15, carbon atoms, and is preferably a branched chain alkyl group having from 7 to 15 carbon atoms. As examples, the second vinyl ester may be vinyl 2-ethyihexanoate, vinyl neodecanoate or vinyl octanoate.

The term "terpolymer", as used herein, requires the polymer to have at least three different repeat units, i.e. to be derivable from at least three different monomers, namely ethylene, monomer (I) and monomer (IT). The term includes polymers derivable from four or more monomers; for example, the polymer may contain units derivable from two or more of monomers (I) and (II) and/or may contain units derivable from monomers of the formula CH2=CR'OOCR5 (III), wherein R5 represents a hydrocarbyl group having 5 or more carbon atoms other than one as defined by R4.

Thus, the present method may be carried out employing two or more of monomers (I) and (II) and/or one or more monomers (III).

As used in this specification the term "hydrocarbyl" refers to a group having a carbon atom directly attached to the rest of the molecule and having a hydrocarbon or predominantly hydrocarbon character. Among these, there may be mentioned hydrocarbon groups, including aliphatic (e.g. alkyl), alicylic (e.g. cycloalkyl), aromatic, aliphatic and alicyclic-substituted aromatic and alicylic groups. Aliphatic groups are advantageously saturated. These groups may contain non-hydrocarbon subsituents provided their presence does not alter the predominantly hydrocarbon character of the group. Examples include 2-ketopropyl, ethoxyethyl, and propoxypropyl. The groups may also or alternatively contain atoms other than carbon in a chain or ring otherwise composed of carbon atoms. Suitable hereto atoms include, for example, nitrogen, sulphur, and, preferably, oxygen. Advantageously, the hydrocarbyl group contains at most 30, preferably at most 15, more preferably at most 10 and most preferably at most 8, carbon atoms.

Also contained within the polymer may be units of the formula -CH2-CHOH-(1V). Also used may be monomers of the formula C(CH3) (CH2 R7) = CHR8 (V) where R7 and R8 each independently represent hydrogen or an alkyl group with up to 4 carbon atoms, the monomers (V) advantageously being derived from isobutylene, 2-methylbut-2-ene or 2-methylpent-2-ene.

Preferably, the number average molecular weight (Mn) of the copolymer (B) is in the range of 2,000 to 10,000, more preferably 3,000 to 8,000, most preferably 4,000 to 7,000. In this specification Mn refers to that value measured by GPC, in comparison with polystyrene standards.

Preferably, the degree of branching of the copolymers (B) is 2 to 10, such as 3 to 9, e.g. in the range of 4 to 8, methyl groups per 100 methylene units. The degree of branching of the polymer is the number of methyl groups per 100 methylene units, as measured by NMR and corrected for the number of methyl and methylene groups in alkyl groups. Reference is made to Figure 1 of EP 1 007 606 and the description thereof for an example of a calculation of the degree of branching.

It is also within the scope of the invention that (B) comprises a mixture of two or more copolymers.

ADDITWE (C) This is a low molecular weight phenolic resins such as ailcyiphenol-aldehyde resins which are known in the art and are described, for example, in US-A-2004/0065004. The alkyl groups have from 1 to 50, preibrably 1 to 20, in particular 4 to 12, carbon atoms. The ailcyl groups are preferably n-, iso-and tert-butyl; n-and isopentyl; n-and isohexyl; n-and isooctyl; n-and isononyl; n-and isodecyl; n-and isododecyl; and octadecyl. The aldehyde is preferably an aliphatic aldehyde and is preferably formaldehyde. The molecular weight of the resins is 400 to 10,000, preferably 400 to 5,000, g/mol.

As further examples of (C), there may be mentioned phenol-aldehyde resins such as alkyl (p-hydroxybenzoate)-aldehycje polymeric condensation products which are known in the art and are described, for example, in EP-A-1 482 024. Preferred are those formed by reaction of an aliphatic aldehyde or ketone or a reactive equivalent with either (i) a straight or branched chain C1 to C7 ailcyl ester of p-hydroxybenzoic acid, or with (ii) a branched chain C8 to C16 alkyl ester of p-hydroxybenzoic acid, or with (iii) a mixture of long chain C8 to Ci8 alkyl esters of p-hydroxbenzoic acid, at least one of said alkyls being branched.

The aldehyde is preferably formaldehyde. The branched alicyl group is preferably 2-ethyihexyl or isodecyl. Generally, the molar ratio of the branched ester to the other ester may be in the range of 5:1 to 1:5. The number average molecular weight of the polymeric condensation products is in the range of 500 to 5,000, preferably 1,000 to 3,000, more preferably 1,000 to 2,000.

The mass:mass ratio of additives (B) and (C) may for example be in the range from 40:1 to 1:20 such as from 30:1 to 1:1.

ADDITIONAL ADDITIVES

The fuel oil composition may comprise one or more additives additional to and different from additives (B) and (C). Their presence may lead to further improvements in performance.

As a preferred example of an additional additive, there may be mentioned: (D) an oil-soluble polar nitrogen compound carrying one or more substituents derived from primary, secondary or tertiary hydrocarbylamines or quaternary hydrocarbyl-ammonium salts, at least one of the hydrocarbyl groups containing 8 to 40 carbon atoms. The oil-soluble polar nitrogen compound is generally one capable of acting as a wax crystal growth inhibitor in fuels; it comprises, for example, one or more of the following compounds: an amine salt and/or anude formed by reacting at least one molar proportion of a hydrocarbyl-substituted amine with a molar proportion of a hydrocarbyl acid having from 1 to 4 carboxylic acid groups or its anhydride, the substituent(s) being of the formula -NR'3R'4 where R'3 represents a hydrocarbyl group containing 8 to 40 carbon atoms and R'4 represents hydrogen or R13, provided that R'3 and R'4 may be the same or different, said substituents constituting part of the amine salt and/or amide groups of the compound.

Ester/amides may be used, containing 30 to 300, preferably 50 to 150, total carbon atoms. These nitrogen compounds are described in US Patent No. 4,211,534. Suitable amines are predominantly C12 to C40 primary, secondary, tertiary or quatemary anunes or mixtures thereof but shorter chain amines may be used provided the resulting nitrogen compound is oil-soluble, normally containing about 30 to 300 total carbon atoms. The nitrogen compound preferably contains at least one straight chain Cg to C40, preferably C14 to C24, alkyl segment.

Suitable amines include primary, secondary, tertiary or quatemary, but are preferably secondary. Tertiary and quaternary amines only form amine salts.

Examples of amines include tetradecylamine, cocoamine, and hydrogenated tallow amine. Examples of secondary amines include diotacedyl amine and methylbehenyl amine. Amine mixtures are also suitable such as those derived from natural materials. A preferred amine is a secondary hydrogenated tallow amine, the alkyl groups of which are derived from hydrogenated tallow fat composed of approximately 4% C14, 31% C16, and 59% C18.

Examples of suitable carboxylic acids and their anhydrides for preparing the nitrogen compounds include ethylenediamine tetraacetic acid, and carboxylic acids based on cyclic skeletons, e.g., cyclohexane-l, 2-dicarboxylic acid, cyclohexene-1, 2-dicarboxylic acid, cyclopentane-1, 2-dicarboxylic acid and naphthalene dicarboxylic acid, and 1, 4dicarboxylic acids including dialkyl spirobislactones. Generally, these acids have about 5 to 13 carbon atoms in the cyclic moiety. Preferred acids useful in the present invention are benzene dicarboxylic acids e.g., phthalic acid, isophthalic acid, and terephthalic acid.

Phthalic acid and its anhydride are particularly preferred. The particularly preferred compound is the amide -amine salt formed by reacting 1 molar portion of phthalic anhydride with 2 molar portions of dihydrogenated tallow amine.

Another preferred compound is the diamide formed by dehydrating this amide-amine salt.

Other examples are long chain alkyl or alkylene substituted dicarboxylic acid derivatives such as amine salts of monoamides of substituted succinic acids, examples of which are known in the art and described in US Patent No. 4,147,520, for example. Suitable amines may be those described above.

Other examples are condensates, for example, those described in EP-A-327427.

Further additional additives may include: (E) comb polymers in which branches containing hydrocarbyl groups having 10 to 30 carbon atoms, are pendant from a polymer backbone, for example maleate, fumarate or itaconate polymers and copolymers; (F) hydrogenated block diene polymers such as comprising at least one crystallisable block, obtainable by end-to-end polymerisation of a linear diene, and at least one non-crystallisable block, the non-crystallisable block being obtainable by 1, 2-configuration polymerisation of a linear diene, by polymerisation of a branched diene, or by a mixture of such polymerisations; (G) compounds containing a ring system; (H) hydrocarbon polymers; and (I) polyoxyalkylene compounds.

The art, for example, WO 96/28 523, contains further description of such additives.

One or more other co-additives such as known in the art may be used. As examples of such other co-additives, there may be mentioned the following: detergents, particulate emission reducers, storage stabilisers, antioxidants, corrosion inhibitors, dehazers, demulsifiers, antifoaming agents, cetane improvers, cosolvents, package compatibilisers and lubricity additives.

PREPARATION OF COMPOSITION

A concentrate comprising the additives of this invention in admixture with a suitable solvent is convenient as a means for incorporating them into fuel oil, which incorporation may be done by methods known in the art. The concentrates may also contain other additives as required and preferably contain from 3 to 75, more preferably 3 to 60, most preferably 10 to 50, mass % of the additives expressed as active ingredient, preferably soluble in oil. Examples of solvent are organic solvents including hydrocarbon solvents, for example petroleum fractions such as naphtha, kerosene, diesel and heater oil; aromatic hydrocarbons such as aromatic fractions, e.g. those sold under the SOLVESSO' tradename; alcohols and/or esters; and paraffinic hydrocarbons such as hexane and pentane and isoparaffins. The solvent must, of course, be selected having regard to its compatibility with the additives and with the fuel oil. The fuel oil composition of the invention advantageously contains additives in a proportion of 0.0005 to 1, advantageously 0.001 to 0.1, and preferably 0.01 to 0.06, % by mass, based on the mass of fuel oil.

EXAMPLES OF THE INVENTION

The invention will now be described in the following examples which are not intended to limit of the scope of the claims hereof.

ADDITIVES

The following additives were used in the examples, either singly or in combination in blends.

(B) an ethylene-vinyl acetate copolymer cold flow improver in the form of a 3:1 (wt:wt) mixture of an arrestor and a nucleator ("EVA"); (C) an alkyl (p-hydroxybenzoate)-formaldehyde condensation copolymer ("HBFC"); (D) a commercially-available wax-anti-settling additive in the form of a polar nitrogen compound ("WASA"); (E) a C14 flimarate-vinyl acetate comb copolymer ("FVA").

FUELS

A middle-distillate fuel containing additions of residual fuel oil and designated Fuel Oil A was used in the examples. The fuel had the following characteristics: Initial boiling point 33.0 C 20% boiling temperature 263.0 C 90% boiling temperature 359.5 C 95% boiling temperature 372.5 C Final boiling point 378.5 C Cloud Point 7 C CFPP -4 C Waxc-4 C 2.5mass% Conradson Carbon Residue 0.3 mass %

FUEL OIL COMPOSITIONS AND TESTING

One or more of the above additives were blended into the above fuel to provide a number of fuel oil compositions.

Samples of each composition were subjected to a rig test designed to simulate the conditions of use of a heating oil composition, namely slow cooling rate and then passage through a mesh filter, before pumping the composition to a boiler.

The conditions of the test were as follows: a) cooling rate: 1 degC per hour b) volume of oil composition sample: 200 ml c) vacuum pressure: 600 mmHg d) filter mesh size: 1 5Oml Results are reported, at a designated temperature, as the time taken in seconds for all of the sample volume to pass through the filter. Normally, a time of within 180 seconds is regarded as a pass, less than 15 seconds as a good pass; a time of greater than 180 seconds is regarded as a fail.

The results are summarised in table form below, where the target rig temperature was -4 C and the additive treat rate was 300 ppm by mass.

A reference example, for comparison purposes, is indicated as "Ref. 1". Examples of the invention are indicated by a number. Also given are results for fuel that contains no additive, i.e. a control, designated "Control".

TABLE

Example Additive(s) in ppm by weight Result (seconds) B (EVA) C (HBFC) D (WASA) E (FVA) Control >180* Ref 1 300 ___________ ___________ ___________ >180** 1 210 67 23 16 2 210 67 23 11 3 210 45 45 9 4 210 23 67 8 210 30 30 30 1 6 210 90 1 Footnotes: A lower numerical result, in seconds, indicates a superior performance.

* >l8Osecs@-2 C <180 secs @ 0 C **<180 secs -2 C The results show that the presence of additive (C) improves the perfonnance of additive (B) over that provided by additive (B) alone. Also, the presence of additives (D) and (E) may influence performance in the tests, though use of additive (E) may give rise to stability problems.

Claims

CLAIMS

1. A fuel oil composition comprising (A) a middle distillate fuel oil, in a major amount, having a carbon residue, measured by ASTM D189, of greater than 0.1% by mass; and the following additives, in respective minor amounts: (B) one or more copolymers of ethylene and a vinyl ester having an alkyl group containing from 1 to 18 carbon atoms; and (C) one or more phenolic resins having a molecular weight of 400 to 10,000 g/mol.

2. A composition as claimed in claim 1 wherein the carbon residue is in the range of 0.2 to 0.5 % by mass.

3. A composition as claimed in claim 1 or claim 2 wherein the fuel oil contains from 2 to % by mass of residual fuel oil.

4. A composition as claimed in any of claims 1 to 3 wherein, in the copolymer(s), (B), the vinyl ester has the formula CH2=CR'OOCR2, wherein R' represents a hydrogen atom or a methyl group and R2 represents an alkyl group having from 1 to 4 carbon atoms.

5. A composition as claimed in any of claims 1 to 4 wherein the copolymer(s) (B) is a terpolymer of ethylene, a vinyl ester as defined in claim 4 and a second, different, vinyl ester having an alkyl group containing from 5 to 15 carbon atoms.

6. A composition as claimed in any of claims 1 to 5 wherein the resin(s), (C), is an alkylphenol-aldehyde resin, the alkyl group having from 1 to 50 carbon atoms.

7. A composition as claimed in claim 6 wherein the resin is an alkyl(p-hydroxybenzoate)-aldehyde polymeric condensation product.

8. A composition as claimed in claim 7 wherein the resin is a formaldehyde condensation copolymer with esters of 4-hydroxybenzoic acid.

9. A composition as claimed in any of claims 1 to 7 further comprising, as an additive: (D) an oil-soluble poiar nitrogen compound carrying one or more substituents derived from primary, secondary or tertiary hydrocarbylamines or quatemary hydrocarbyl-ammonium salts, at least one of the hydrocarbyl groups containing 8 to 40 carbon atoms 10. A composition as claimed in any of claims 1 to 9 wherein the additives are present in the range of 0.1 to 0.3 % by mass, based on the mass of the fuel oil.