HK40060624B - Emulsifier package with quaternary ammonium surfactant for fuel emulsion - Google Patents

Description

Emulsifier packages containing quaternary ammonium surfactants for use in fuel emulsions

This invention relates to fuel emulsions for powering diesel engines, comprising water, fuel, and an emulsifier package containing a quaternary ammonium surfactant. The invention also relates to a method for powering a diesel engine with a fuel emulsion, the method comprising the step of preparing the fuel emulsion by emulsifying fuel and water in the presence of the emulsifier package; and further relates to an emulsifier package for emulsifying fuel and water, the emulsifier package containing a quaternary ammonium surfactant and at least one nonionic surfactant that is an alkoxylate, wherein the quaternary ammonium surfactant is obtained by reacting a quaternary ammonium-containing nitrogen compound, particularly a tertiary amino group, with a quaternizing agent, the quaternizing agent converting at least one quaternary ammonium-containing amino group, particularly a tertiary amino group, into a quaternary ammonium group, wherein the quaternizing agent is a combination of a hydrocarbon epoxide and a free hydrocarbon-substituted polycarboxylic acid.

Water-based fuel emulsions used to power diesel engines are known.

The object of this invention is to find an emulsifier package for fuel emulsions that is inexpensive, easy to prepare, storage stable, based on commercially available emulsifiers, and based solely on carbon, hydrogen, nitrogen, and oxygen, and allows for rapid and easy emulsification even under low shear stress. The emulsifier package should produce a low-foaming fuel emulsion, possessing a low cloud point, providing corrosion protection, low foaming, improved emulsion filterability, and reduced sedimentation when fuel is mixed with water. The emulsifier package should stabilize fuel emulsions containing various types of water at high water concentrations, various temperatures, and pressures.

This objective is achieved through a fuel emulsion for powering a diesel engine, the fuel emulsion comprising...

-water,

- Fuel, and

- Emulsifier package containing quaternary ammonium surfactants.

This objective is also achieved by an emulsifier package for emulsifying fuel and water, the emulsifier package containing...

- Quaternary ammonium surfactants, which can be obtained by reacting a quaternizable nitrogen compound containing at least one quaternizable amino group, especially a tertiary amino group, with a quaternizing agent, said quaternizing agent converting at least one quaternizable amino group, especially a tertiary amino group, into a quaternary ammonium group, wherein said quaternizing agent is a combination of a hydrocarbon epoxide and a free hydrocarbon-substituted polycarboxylic acid, and

- At least one of the nonionic surfactants is an alkoxylated compound.

Fuels typically contain hydrocarbons, such as alkanes, cycloalkanes, and aromatics. Fuels can be obtained from petroleum distillation as a distillate or residue. Fuels are typically liquid fuels. Examples of fuels are gasoline, diesel, or biodiesel, or mixtures thereof, with gasoline or diesel being preferred. In particular, the fuel is diesel. Gasoline may contain primarily C4 to C12 alkanes, alkenes, and cycloalkanes. Diesel may contain saturated hydrocarbons and aromatics. Biodiesel typically comprises lower alkyl fatty acid esters, for example, prepared by transesterification of triglycerides with lower alcohols (e.g., methanol or ethanol).

The viscosity of the fuel can vary over a wide range, for example, from 1 to 10,000 ^mm² /s at 40°C (ISO 3104) or from 1 to 1,000 ^mm² /s at 50°C (ISO 3104).

The fuel can be marine fuel, such as MGO (Marine Gas Oil), MDO (Marine Diesel), IFO (Intermediate Fuel Oil), MFO (Marine Fuel Oil), or HFO (Heavy Fuel Oil). Other examples of marine fuels include IFO 380 (intermediate fuel oil with a maximum viscosity of 380 centipoise (<3.5% sulfur)), IFO 180 (intermediate fuel oil with a maximum viscosity of 180 centipoise (<3.5% sulfur)), LS380 (low-sulfur (<1.0%) intermediate fuel oil with a maximum viscosity of 380 centipoise), LS 180 (low-sulfur (<1.0%) intermediate fuel oil with a maximum viscosity of 180 centipoise), and LSMGO (low-sulfur (<0.1%) marine gas oil, in accordance with the EU Sulfur Directive 2005/33/EC). (ur directive 2005/33/EC) is commonly used in European ports and anchorages, or ULSMGO (ultra-low sulfur marine gas oil, also known as ultra-low sulfur diesel oil (sulfur content up to 0.0015%). Other suitable marine fuels conform to DIN ISO 8217 categories ISO-F-DMX, DMA, DFA, DMZ, DFZ or DFB, or ISO-F RMA, RMB, RMD, RME, RMG or RMK. Other suitable marine fuels are distilled marine diesel oil or residual marine diesel oil.

The viscosity of fuels (e.g., marine fuels) can vary over a wide range, for example, from 1 to 10,000 ^mm² /s at 40°C (ISO 3104) or from 1 to 1,000 ^mm² /s at 50°C (ISO 3104).

Fuel emulsions may contain at least 10, 20, 25, 30, 35, 40, 50, or 60% by weight of fuel. Fuel emulsions may contain up to 30, 40, 50, or 60% by weight of fuel. Fuel emulsions may contain 10 to 70%, 20 to 60%, or 30 to 50% by weight of fuel.

For ecological reasons, low-sulfur fuels are gaining increasing attention. Suitable low-sulfur fuels can contain less than 1, 0.5, 0.2, or 0.1% sulfur by weight. An example is ULSFO, which contains less than 0.1% sulfur by weight. Diesel fuels, primarily used in automobiles, can have sulfur contents of up to 2000 ppm, 500 ppm, 350 ppm, 50 ppm, or 10 ppm.

Any type of water can be used, such as tap water, well water, seawater, ocean water, rainwater, distilled water, wastewater, or deionized water. Water with low chlorine concentration is preferred to avoid corrosion, such as tap water, distilled water, or rainwater.

Water can have low hardness, for example, less than 8.4°dH (German hardness), or calcium carbonate concentration less than 1.5 mmol/L.

Water can have low salinity, for example, up to 1000, 500, 100, 10 or 1 ppmw, such as in NaCl-based concentration meters.

Fuel emulsions may contain at least 10, 20, 30, 40, 50, 55, 60, 65, or 70% by weight of water. Fuel emulsions may contain up to 50, 60, 70, 75, 80, 85, or 90% by weight of water. Fuel emulsions may contain 30 to 90%, 40 to 80%, or 50 to 80% by weight of water.

The weight ratio of water to fuel can be 1:0.1 to 1:10, or 1:0.5 to 1:5, or 1:0.7 to 1:3, or preferably 1:0.1 to 1:2.4.

The fuel emulsion can be an oil-in-water emulsion or an oil-in-water emulsion, with an oil-in-water emulsion being preferred.

The fuel emulsion can be a crude emulsion, a fine emulsion, or a microemulsion, with a crude emulsion being preferred.

The diameter of the dispersed phase (e.g., fuel) in the fuel emulsion can be from 0.01 to 100 μm, preferably from 1 to 100 μm.

Fuel emulsions can be present at temperatures ranging from 0 to 100°C, preferably from 15 to 90°C.

Fuel emulsions can be present at pressures of 1 to 100 bar, preferably 1 to 10 bar.

The emulsifier package contains a quaternary ammonium surfactant. Suitable quaternary ammonium surfactants are R’R”R”’R””N+X-, where R’, R”, R”’, and R”” are independent aliphatic or aromatic groups, and X is a halogen (e.g., chloride) or anionic aliphatic or aromatic group. Examples are alkyltrimethylammonium chloride, where R contains 8 to 18 carbon atoms, such as dodecyltrimethylammonium chloride; dialkyldimethylammonium chloride, where the alkyl chain length is 8 to 18 carbon atoms; N,N-dialkylimidazoline compounds; and N-alkylpyridinium salts.

Quaternary ammonium surfactants are preferably reaction products that can be obtained through the following methods:

- A quaternizable nitrogen compound containing at least one quaternizable amino group, especially a tertiary amino group, is reacted with a quaternizing agent, which converts the at least one quaternizable amino group, especially a tertiary amino group, into a quaternary ammonium group.

-The quaternizing agent is a combination of a hydrocarbon epoxide and a free hydrocarbon-substituted polycarboxylic acid.

The product of this reaction is also referred to below as an "epoxide-quaternized amine". Suitable epoxide-quaternized amines are described in detail in WO 2017/009208.

Quaternary ammonium nitrogen compounds can be selected from

a) At least one alkylamine comprising at least one compound of general formula (3).

R _a R _b R _c N (3)

At least one (e.g., one or two) of the _Ra , _Rb and _Rc groups is a straight-chain or branched, saturated or unsaturated _C8 - _C40 -alkyl group (especially a straight-chain or branched _C8 - _C40 -alkyl group), and the other groups are the same or different, straight-chain or branched, saturated or unsaturated _C1 - _C6 -alkyl groups (especially _C1 - _C6 -alkyl groups);

b) At least one polyolefin-substituted amine, comprising at least one quaternizable amino group, especially a tertiary amino group;

c) at least one polyether-substituted amine comprising at least one quaternizable amino group, particularly a tertiary amino group; and

d) A reaction product of a hydrocarbon-substituted acylating agent and at least one compound, said compound comprising a nitrogen or oxygen atom and further comprising at least one quaternizable amino group, especially a tertiary amino group; and

e) Its mixture.

In the compound of formula (3), preferably all _Ra , _Rb , and _Rc groups are the same or different, straight-chain or branched, saturated or unsaturated _C8 - _C40 -alkyl groups, especially straight-chain or branched _C8 - _C40 -alkyl groups. More preferably, at least two of the _Ra , _Rb , and _Rc groups are the same or different, and each is a straight-chain or branched _C10 - _C20 -alkyl group, and the other group is a _C1 - _C4 -alkyl group.

The compound of formula (3) preferably has a segment of formula NR _a R _b , wherein one group has an alkyl group having 8 to 40 carbon atoms, and the other group has an alkyl group having up to 40, and more preferably 8 to 40, carbon atoms. The _{R c} group is particularly a short-chain _C1 - _C6 -alkyl group, such as methyl, ethyl, or propyl. _Ra and R _b can be straight-chain or branched, and/or can be the same or different. For example, _Ra and R _b can be straight-chain _C12 - _C24 -alkyl groups. Alternatively, only one of the two groups can be long-chain (e.g., having 8 to 40 carbon atoms), while the other group can be methyl, ethyl, or propyl. Suitablely, the NR _a R _b segment is derived from a secondary amine, such as dioctadecylamine, dicocoamine, hydrogenated dicarboxylic amine, and methylbehenylamine. Mixtures of amines available from natural materials are also suitable. One example is a secondary hydrogenated animal fat amine, wherein the alkyl group is derived from hydrogenated animal fat and contains about 4% by weight of _C14 -alkyl, 31% by weight of _C16 -alkyl and 59% by weight of _C18 -alkyl. The corresponding tertiary amine of formula (3) is sold, for example, by Akzo Nobel under the brand names M2HT or M2C.

Compounds of formula (3) may also be compounds in which the _Ra , _Rb , and _Rc groups have the same or different long-chain alkyl groups, especially straight-chain or branched alkyl groups having 8 to 40 carbon atoms. Compounds of formula (3) may also be compounds in which the _Ra , _Rb , and _Rc groups have the same or different short-chain alkyl groups, especially straight-chain or branched alkyl groups having 1 to 7 carbon atoms or especially 1 to 4 carbon atoms. Other examples of suitable compounds of formula (3) are N,N-dimethyl-N-(2-ethylhexyl)amine, N,N-dimethyl-N-(2-propylheptyl)amine, dodecyl dimethylamine, hexadecyl dimethylamine, oleyl dimethylamine, stearyl dimethylamine, heptadecanyl dimethylamine, cocoyl dimethylamine, dicocoyl methylamine, animal fat dimethylamine, dianilofat methylamine, tri(dodecyl)amine, tri(hexadecyl)amine, tri(octadecyl)amine, soybean dimethylamine, tri(2-ethylhexyl)amine, and Alamine 336 (tri-n-octylamine). Non-limiting examples of short-chain tertiary amines include: trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, ethyldimethylamine, dimethylethylamine, n-propyldimethylamine, isopropyldimethylamine, n-propyldiethylamine, isopropyldiethylamine, n-butyldimethylamine, n-butyldiethylamine, and n-butyldipropylamine. Short-chain triamines are also suitable, especially when the quaternizing agent carries one or more alkyl groups R_{_d} having more than one carbon atom or one or more aryl groups R_{_d} .

Suitable quaternizable nitrogen compounds are polyolefin-substituted amines having at least one tertiary nitrogen group. This group of compounds is also known and described, for example, in WO 2008/060888 or US 2008/0113890. Such polyolefin-substituted amines having at least one tertiary amino group can be derived from olefin polymers and amines (e.g., ammonia, monoamines, polyamines, or mixtures thereof). In another embodiment, the amine in the polyolefin-substituted amine can be a polyamine. Polyamines can be aliphatic, alicyclic, heterocyclic, or aromatic. Examples of polyamines include alkylene polyamines, hydroxyl-containing polyamines, aryl polyamines, and heterocyclic polyamines. The number average molecular weight of such polyolefin-substituted amines is from about 500 to about 5000, for example from 1000 to about 1500 or from about 500 to about 3000.

Preferred polyolefin-substituted amines are alkylene polyamines comprising the following formula:

HN( ^R5 )-(alkylene-N( ^R5 )) _n- ( ^R5 )

Wherein n is from 1 to about 10, and for example from 2 to about 7, or from 2 to about 5, and the "alkylene" group has 1 to about 10 carbon atoms, for example from 2 to about 6, or from 2 to about 4 carbon atoms; in each case, the ^R5 group is independently hydrogen, an aliphatic group, a hydroxyl-substituted or amine-substituted aliphatic group with up to about 30 carbon atoms. Typically, ^R5 is H or a lower alkyl group (an alkyl group having 1 to about 5 carbon atoms), especially H.

Such alkylene polyamines include: methylene polyamines, ethylene polyamines, butylene polyamines, propylene polyamines, pentylene polyamines, hexylene polyamines, and heptamethine polyamines. Higher homologues of these amines, as well as related aminoalkyl-substituted piperazines, are also included. Specific alkylene polyamines include: ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, propylenediamine, 3-dimethylaminopropylamine, trimethylenediamine, hexamethylenediamine, decamethyldiamine, octamethyldiamine, di(heptamethyl)triamine, trimethylenetetramine, pentaethylenehexamine, di(triethylenetriamine), N-(2-aminoethyl)piperazine, and 1,4-bis(2-aminoethyl)piperazine.

Suitable polyether-substituted amines are known in WO2013/064689. Such substituted amines are particularly those having at least one polyether substituent, especially one monomer unit having the general formula Ic.

-[-CH(R ₃ )-CH(R ₄ )-O-]- (Ic)

_R3 and _R4 may be the same or different, and each may be H, alkyl, alkylaryl, or aryl. The number average molecular weight of the polyether-substituted amines may be from 500 to 5000, especially from 800 to 3000 or from 900 to 1500.

Polyether-substituted amines, especially nitrogen compounds of general formula Ia-1 or Ib-2.

_R1 and _R2 may be the same or different, and each may be alkyl, alkenyl, hydroxyalkyl, hydroxyalkenyl, aminoalkyl or aminoalkenyl, or _R1 and _R2 together may be alkylene, oxyalkylene or aminoalkylene; _R3 and _R4 may be the same or different, and each may be H, alkyl, alkylaryl or aryl; _R6 may be alkyl, alkenyl, optionally monounsaturated or polyunsaturated cycloalkyl, aryl, and in each case optionally substituted for, for example, at least one hydroxyl or alkyl group, or interrupted by at least one heteroatom; A may be a straight-chain or branched alkylene group, optionally interrupted by one or more heteroatoms (such as N, O and S); n may be an integer value from 1 to 50.

Suitable reaction products of hydrocarbon-substituted acylating agents with compounds are known in WO2013/000997, said compounds containing a nitrogen or oxygen atom and further containing at least one quaternizable amino group, especially a tertiary amino group. Suitable hydrocarbon-substituted acylating agents include polycarboxylic acid compounds. The polycarboxylic acid compounds used are aliphatic di- or poly(e.g., tri- or tetra-)carboxylic acids, especially di-, tri-, or tetra-carboxylic acids and their analogs, such as acid anhydrides or lower alkyl esters (partially or fully esterified), and optionally substituted by one or more (e.g., 2 or 3) especially long-chain alkyl and/or high molecular weight hydrocarbon groups, especially polyalkylene groups. Examples are _C3 - _C10 polycarboxylic acids, such as dicarboxylic acids, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, octanoic acid, azelaic acid, and sebacic acid, and their branched analogs; and tricarboxylic acids, citric acid; and their acid anhydrides or lower alkyl esters. Polycarboxylic acid compounds can also be obtained by the addition of the corresponding monounsaturated acid to at least one long-chain alkyl group and/or a high-molecular-weight hydrocarbon group. Suitable examples of monounsaturated acids are fumaric acid, maleic acid, and itaconic acid.

The number average molecular weight ( _Mn ) of the hydrophobic "long-chain" or "high-molecular-weight" hydrocarbon groups that ensure the full solubility of the quaternization products in fuel is 85 to 20,000, for example 113 to 10,000, or 200 to 10,000, or 350 to 5,000, for example 350 to 3,000, 500 to 2,500, 700 to 2,500, or 800 to 1,500. Typical hydrophobic hydrocarbon groups include polypropylene, polybutene, and polyisobutylene groups, for example, with average molecular weights _Mn of 3,500 to 5,000, 350 to 3,000, 500 to 2,500, 700 to 2,500, and 800 to 1,500.

Quaternizable nitrogen compounds that react with the above polycarboxylic acid compounds are selected from:

a) A hydroxyalkyl-substituted monoamine or polyamine having at least one quaternized (e.g., choline) or quaternizable primary, secondary or tertiary amino group;

b) Straight-chain or branched, cyclic, heterocyclic, aromatic or non-aromatic polyamines having at least one primary or secondary (anhydride-reactive) amino group and at least one quaternized or quaternizable primary, secondary or tertiary amino group.

c) Piperazine.

Suitable quaternizing agents are selected from hydrocarbon epoxides, such as the epoxides of formula (4).

The R _d groups present may be the same or different, and each is an H or a hydrocarbon group, wherein the hydrocarbon group has at least 1 to 10 carbon atoms. More particularly, these are aliphatic or aromatic groups, such as straight-chain or branched _C1–10 -alkyl groups, or aromatic groups, such as phenyl or _C1–4 -alkylphenyl groups. Examples of suitable hydrocarbon epoxides include aliphatic and aromatic epoxides, for example, more specifically, _C2–12... -Epoxyalkanes, such as ethylene oxide, propylene oxide, 1,2-epoxybutane, 2,3-epoxybutane, 2-methyl-1,2-epoxypropane (epoxyisobutane), 1,2-epoxypentane, 2,3-epoxypentane, 2-methyl-1,2-epoxybutane, 3-methyl-1,2-epoxybutane, 1,2-epoxyhexane, 2,3-epoxyhexane, 3,4-epoxyhexane, 2-methyl-1,2-epoxypentane, 2-ethyl-1,2-epoxybutane, 3-methyl-1,2-epoxypentane, 1,2-epoxydecane, 1,2-epoxydodecane, or 4-methyl-1,2-epoxypentane; and aromatically substituted ethylene oxides, such as optionally substituted styrene oxide, especially styrene oxide or 4-methylstyrene oxide.

Suitable free hydrocarbon-substituted polycarboxylic acids are free hydrocarbon-substituted unsaturated, especially saturated, optionally substituted, and especially unsubstituted protic acids, for example, more specifically, hydrocarbon-substituted dicarboxylic acids, especially hydrocarbon-substituted _C3 - _C28 or _C3 - _C12 dicarboxylic acids, especially unsubstituted saturated _C3 - _C6 dicarboxylic acids. Here, suitable dicarboxylic acids are saturated acids, such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, octanoic acid, azelaic acid, sebacic acid, undecanoic acid, and dodecanoic acid, or acids with higher molecular weights, such as tetra-, hexa-, or octadecanoic acid; substituted acids, such as malic acid, α-ketoglutaric acid, oxaloacetic acid; glutamic acid; aspartic acid; and unsaturated acids, such as maleic acid and fumaric acid; for example, more specifically, malonic acid, succinic acid, glutaric acid, adipic acid, and pimelic acid. Also suitable are aromatic dicarboxylic acids, such as phthalic acid. If desired, alkyl-substituted dicarboxylic acids in the form of anhydrides can also be used. For quaternization, the ring-opening of the anhydride is initiated by addition with water.

Hydroxyl-substituted dicarboxylic acids can, in principle, be prepared by hydrolysis of the corresponding alkyl-substituted dicarboxylic anhydride in a known manner, for example as described in DE 2443537. Hydrolysis is preferably carried out at a temperature of 50°C to 150°C using a stoichiometric amount of water, but an excess of water may also be used. Hydrolysis can be carried out in the absence of a solvent or in the presence of an inert solvent. Typical examples are solvents selected from the Solvesso series, toluene, xylene, or straight-chain and branched saturated hydrocarbons (e.g., alkanes or cycloalkanes). The solvent may be removed after hydrolysis, but it is preferred to retain the solvent and use it as a solvent or co-solvent for subsequent quaternization. Preferred alkyl-substituted dicarboxylic anhydrides are alkyl-substituted succinic anhydrides, such as those sold by Pentagon: n-dodecenyl succinic anhydride CAS 19780-11-1, n-octadecenyl succinic anhydride CAS 28777-98-2, isooctadecenyl succinic anhydride CAS 28777-98-2, isohexadecenyl succinic anhydride/isooctadecenyl succinic anhydride CAS 32072-96-1 and 28777-98-2, n-octenyl succinic anhydride CAS 26680-54-6, and tetrapropylene succinic anhydride CAS 26544-38-7.

The alkyl substituent of the carboxylic acid is preferably a polyalkylene group with a degree of polymerization of 2 to 100, 3 to 50, or 4 to 25. Polyisobutylene succinic anhydride (PIBSA) is also preferred. The preparation of PIBSA from polyisobutylene (PIB) and maleic anhydride (MA) is known in principle, yielding a mixture of PIBSA and bismaleitized PIBSA (BM PIBSA, see Scheme 1 below), which is typically further processed as is without purification. Particularly preferred are PIBSA with a bismaleitization level of up to 30%, preferably up to 25%, and more preferably up to 20%. Typically, the bismaleitization level is at least 2%, preferably at least 5%, and more preferably at least 10%. Controlled preparation methods are described, for example, in US 5,883,196. For preparation, highly reactive PIBs (HR-PIBs) with an Mn of 500 to 3000, for example 550 to 2500, 800 to 1200, or 900 to 1100 are particularly suitable. Mn is determined by GPC, as described in US 5,883,196. Particularly preferred PIBSAs prepared from HR-PIBs (Mn = 1000) have a hydrolysis value of 85-95 mg KOH/g. A non-limiting example of a particularly suitable PIBSA is SA F from BASF, prepared from HR-PIBs (Mn = 1000) with a bismaleic acidification level of 15% and a hydrolysis value of 90 mg KOH/g.

Alternatively, though less preferred, the alkyl-substituted dicarboxylic anhydride may be reacted not with water but with an alcohol (preferably a monohydric alcohol) or amine, more preferably an alcohol, to yield the corresponding monoester or monoamide of the alkyl-substituted dicarboxylic acid. Importantly, in this reaction, an acidic functional group remains in the molecule. If quaternization is carried out in the presence of an alcohol, it is preferable to use the same alcohol used as the solvent in the quaternization for the reaction of the alkyl-substituted dicarboxylic anhydride, i.e., preferably 2-ethylhexanol or 2-propylheptanol, or butyl diethylene glycol, butyl ethylene glycol, methoxypropoxypropanol, or butoxydipropanol. This alcoholysis is preferably carried out at a temperature of 50 to 150°C with a stoichiometric amount of alcohol or amine, but an excess of alcohol or amine, preferably an alcohol, may also be used. In that case, the excess alcohol or amine, preferably an alcohol, is suitably retained in the reaction mixture and used as a solvent in the subsequent quaternization.

The emulsifier package may contain at least one (e.g., one, two, or three) nonionic surfactants, preferably at least one of which is an alkoxylated nonionic surfactant.

Suitable nonionic surfactants are alkoxylates, alkyl glucosides and alkyl polyglucosides, or fatty acids with glycerol or sorbitol (e.g., monoesters, diesters and triesters) (e.g. glyceryl monostearate, sorbitol monooleate, sorbitol tristearate).

Suitable alkoxylates are

Alkoxylated alkanols, particularly ethoxylated fatty alcohols and ethoxylated oxo alcohols, such as ethoxylated lauryl alcohol, ethoxylated isotriadecyl alcohol, ethoxylated cetyl alcohol, ethoxylated stearyl alcohol, and their esters, such as acetate esters.

Alkoxylated alkylphenols, such as ethoxylated nonylphenyl, ethoxylated dodecylphenyl, ethoxylated isotridecylphenol, and their esters, such as acetates.

-A block copolymer of ethylene oxide and propylene oxide,

-Ethoxylated alkyl glucosides and alkyl polyglucosides

-Ethoxylated fatty amines,

-Ethoxylated fatty acids,

-Ethoxylated fatty acids with esters of glycerol or sorbitol, such as ethoxylated glyceryl monostearate.

- Ethoxylated compounds of vegetable oils or animal fats, such as corn oil ethoxylated compounds, castor oil ethoxylated compounds, and animal fat ethoxylated compounds.

- Ethoxylated fatty amines or fatty amides.

Preferred nonionic surfactants are ethoxylated fatty alcohols, castor oil ethoxylates, and fatty amide ethoxylates.

Preferably, the alkoxylated compound is an alkoxylated alkanol. In another form, suitable alkoxylated compounds include alkoxylated alkanols, which are typically alkoxylated straight-chain or branched, saturated or unsaturated _C1 - _C20 (preferably _C8 -C20) alkanols, preferably ethoxylated, ethoxylated and propoxylated, or ethoxylated and butoxylated, straight-chain or branched, saturated _C2 - _C18 (preferably _C8 - _C18 ) alkanols, or more preferably ethoxylated and propoxylated C4 _{- C18} (preferably _C12 - _C20 ) alkanols. The alkanol units of the alkoxylated alkanol can be an industrial-grade mixture of various chain lengths and isomers. The total number of alkoxy units in the alkoxylated alkanol can be ₅ to 30, preferably 10 to 25 alkoxy units (e.g., ethylene oxide and/or propylene oxide units). Alkoxy units (e.g., EO and PO units) preferably appear in a block sequence, particularly in a diblock sequence. The polyalkoxylated chain of the alkoxylated alkanol may be capped with hydroxyl or C1 to C4 alkyl groups, wherein hydroxyl is preferred. In another form, alkoxy units (e.g., EO and PO units) preferably appear in a block sequence, particularly in a diblock sequence, and the polyalkoxylated chain of the alkoxylated alkanol is capped with hydroxyl.

In another form, a suitable alkoxylated compound is an alkoxylated alkanol of formula (I).

R ^e -O-(AO) _m -R ^f (I)

in

^Re is a straight-chain or branched alkyl or alkylene group having 1 to 32, preferably 4 to 32, more preferably 10 to 22 carbon atoms.

AO is an ethylene oxide group, an propylene oxide group, an butyl oxide group, a pentyl oxide group, a styrene oxide group, or a mixture of the above groups in a random or block sequence (preferably a diblock sequence).

m is a number from 1 to 30, and

^Rf is hydrogen or an alkyl group having 1 to 4 carbon atoms.

Alkoxylated compounds can also be alkoxylated block polymers, which may contain blocks of polyethylene oxide and polypropylene oxide. Alkoxylated block polymers typically contain at least 20% by weight, preferably at least 30% by weight, of polymerized ethylene oxide. In a preferred form, the alkoxylated block polymer contains at least 10% by weight, preferably at least 15% by weight, of polymerized ethylene oxide. The alkoxylated block polymer is preferably an A-B-A type block polymer containing block polyethylene oxide (block "A") and polypropylene oxide (block "B"). The alkoxylated block polymer is typically end-capped with hydroxyl groups. The molecular weight of the alkoxylated block polymer can be from 1000 to 30000 Da, preferably from 2000 to 15000 Da.

Preferably, the emulsifier contains at least two nonionic surfactants, wherein the nonionic surfactants are alkoxylated compounds selected from ethoxylated fatty amides, castor oil ethoxylated compounds, and ethoxylated fatty alcohols.

For example, the emulsifier package contains at least two ethoxylated fatty alcohols; or at least two castor oil ethoxylates; or at least an ethoxylate of a fatty amide and a castor oil ethoxylate; or at least an ethoxylate of a fatty amide and an ethoxylated fatty alcohol.

The emulsifier package may contain at least 0.5, 1, 2, 3 or 4% by weight of a quaternary ammonium surfactant, such as an epoxide-quaternized amine.

The emulsifier package may contain up to 50, 30, 20, 15, 10, 8 or 7% by weight of a quaternary ammonium surfactant, such as an epoxide-quaternized amine.

The emulsifier package may contain 0.1 to 40, 0.5 to 15, or 1 to 10% by weight of a quaternary ammonium surfactant, such as an epoxide-quaternized amine.

The emulsifier package may contain at least 40, 50, 60, 70, 80 or 85% by weight of nonionic surfactant.

The emulsifier package may contain up to 99, 97, 95, 93 or 91% by weight of nonionic surfactant.

The emulsifier package may contain 40 to 99, 50 to 95, or 60 to 95% by weight of nonionic surfactant.

If there is more than one nonionic surfactant, its quantity involves the sum of all nonionic surfactants.

The emulsifier package may contain at least 20, 40, or 50% by weight of an ethoxylated fatty amide.

The emulsifier package may contain up to 85, 75, 70 or 65% by weight of fatty amide ethoxylates.

The emulsifier package may contain 30 to 85, 40 to 80, or 50 to 70% by weight of an ethoxylated fatty amide.

The emulsifier package may contain at least 10, 20, or 25% by weight of ethoxylated fatty alcohols and/or castor oil ethoxylates.

The emulsifier package may contain up to 60, 45 or 40% by weight of ethoxylated fatty alcohols and/or castor oil ethoxylates.

The emulsifier package may contain 15 to 50, 20 to 40, or 25 to 35% by weight of ethoxylated fatty alcohols and/or castor oil ethoxylates.

The emulsifier package may contain:

0.5 to 30% by weight of quaternary ammonium surfactants, such as epoxide-quaternized amines; and

70 to 99.5% by weight of nonionic surfactants, such as ethoxylated fatty amides, castor oil ethoxylated compounds, and alkoxylated fatty alcohols.

In another form, the emulsifier package may contain:

0.5 to 15% by weight of a quaternary ammonium surfactant, such as an epoxide-quaternized amine; and

85 to 99.5% by weight of nonionic surfactants, such as ethoxylated fatty amides, castor oil ethoxylated compounds, and alkoxylated fatty alcohols.

In another form, the emulsifier package may contain:

0.5 to 10% by weight of quaternary ammonium surfactants, such as epoxide-quaternized amines; and

90 to 99.5% by weight of nonionic surfactants, such as ethoxylated fatty amides, castor oil ethoxylated compounds, and alkoxylated fatty alcohols.

The emulsifier package may contain:

0.5 to 30 wt% of epoxide-quaternized amines; and

70 to 99.5% by weight of at least one nonionic surfactant, which is an alkoxylated surfactant, such as an ethoxylated fatty amide, a castor oil ethoxylated surfactant, and an ethoxylated fatty alcohol alkoxylated surfactant.

In another form, the emulsifier package may contain:

0.5 to 15 wt% of epoxide-quaternized amines; and

85 to 99.5% by weight of at least one nonionic surfactant, which is an alkoxylated surfactant, such as an ethoxylated fatty amide, a castor oil ethoxylated surfactant, and an ethoxylated fatty alcohol alkoxylated surfactant.

The emulsifier package may contain:

0.5 to 30 wt% of epoxide-quaternized amines; and

70 to 99.5% by weight of at least two nonionic surfactants selected from fatty amides, castor oil ethoxylates, and ethoxylated fatty alcohols.

In another form, the emulsifier package may contain:

0.5 to 15 wt% of epoxide-quaternized amines; and

At least two nonionic surfactants, comprising 85 to 99.5% by weight, selected from ethoxylated fatty amides, ethoxylated castor oil, and alkoxylated fatty alcohols.

In another form, the emulsifier package may contain:

0.5 to 30% by weight of quaternary ammonium surfactants, such as epoxide-quaternized amines; and

40 to 80% by weight of fatty amide ethoxylates; and

10 to 50% by weight of ethoxylated fatty alcohols and/or castor oil ethoxylates.

In another form, the emulsifier package may contain:

0.5 to 15% by weight of a quaternary ammonium surfactant, such as an epoxide-quaternized amine; and

50 to 70% by weight of fatty amide ethoxylates; and

20 to 40% by weight of ethoxylated fatty alcohols and/or castor oil ethoxylates.

Emulsifier packets are typically liquid at 20°C.

The emulsifier package may contain at least 40, 50, 60, 70, 80, or 90% by weight of all quaternary ammonium surfactants and nonionic surfactants.

The emulsifier package may contain polyisobutylene-based additives, such as the reaction product of polyisobutylene succinic anhydride and an alkylene amine, or a quaternized detergent obtained by quaternizing the above reaction product of polyisobutylene succinic anhydride with an alkylene amine having an amino group capable of condensing with the polyisobutylene succinic anhydride and a tertiary amino group. The emulsifier package may contain at least 1, 5, 10, or 15% by weight of polyisobutylene-based additives. The emulsifier package may contain up to 70, 60, 55, 50, 40, 30, or 20% by weight of polyisobutylene-based additives.

Suitable polyisobutylene-based additives are the reaction products of polyisobutylene succinic anhydride and alkylene amines. In a preferred embodiment, the alkylene amine may be an oligomeric ethylene amine, preferably diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, or mixtures thereof. Suitable examples are disclosed in WO 14/184066, particularly component (C) and lines 32 to 12 on page 9, which are incorporated herein by reference. In a preferred embodiment, the alkylene amine may be an alkylene amine having an amino group capable of condensing with polyisobutylene succinic anhydride and a tertiary amino group. Suitable examples are disclosed in paragraph [0027] of WO 2010/132259 A1, wherein 3-dimethylaminopropylamine is particularly preferred. In the reaction products, such alkylene amines can be mostly bound by amide groups, as described in WO 2010/132259 A1, especially as described in “Preparation Material A”, or by imide groups, as described in WO 2006/135881 A2, especially as described in “Preparation Material A”.

Other suitable polyisobutylene-based additives are quaternized detergents, which can be obtained by quaternizing the above-described reaction product of polyisobutylene succinic anhydride with an alkylene amine having an amino group capable of condensing with polyisobutylene succinic anhydride and a tertiary amino group. The quaternizing agent can be selected from dialkyl sulfates, benzyl halides, hydrocarbon-substituted carbonates, and hydrocarbon epoxides, in the presence or absence of an acid or mixture thereof, with hydrocarbon epoxides being particularly preferred. Examples are described in WO2006/135881 A2, WO 2010/132259 A1, or WO 2012/004300, which are incorporated herein by reference.

The emulsifier package may contain organic solvents, such as hydrocarbons (e.g., aliphatic, aromatic, or mixtures thereof), ethers, ketones, or alcohols (e.g., 2-ethylhexanol, 2-propylheptanol, butyl diethylene glycol, butyl ethylene glycol, methoxypropoxypropanol, or butoxydipropanol). Preferred organic solvents are alcohols and hydrocarbons.

The emulsifier package may contain up to 20, 15, or 10% by weight of organic solvent, for example, 0.5 to 15 or 1 to 10% by weight.

Fuel or emulsifier packages may contain other additives such as carrier oils, cold flow improvers, lubrication improvers, corrosion inhibitors, demisting agents, defoamers, cetane number improvers, combustion improvers, antioxidants or stabilizers, antistatic agents, metallocenes, metal passivators, and/or dyes. Fuel or emulsifier packages may contain up to 50, 30, 10, 5, or 1% by weight of other additives. Emulsifier packages may not contain other additives.

The fuel emulsion contains up to 5, 3, 2, 1, 0.8, 0.6, 0.4 or 0.3% by weight of emulsifier, based on diesel fuel.

The fuel emulsion contains 0.001 to 1.0 wt%, 0.01 to 0.5 wt%, or 0.05 to 0.3 wt% of emulsifier, based on diesel fuel.

The fuel emulsion contains up to 2, 1, 0.5, 0.2, 0.1, or 0.08% by weight of emulsifier packets, based on the fuel emulsion.

The fuel emulsion contains 0.001 to 0.5, 0.005 to 0.15, or 0.02 to 0.08% by weight of an emulsifier packet, based on the fuel emulsion.

The present invention also relates to a method for powering a diesel engine with a fuel emulsion, comprising the step of preparing a fuel emulsion by emulsifying fuel and water in the presence of an emulsifier packet.

Powering diesel engines with fuel emulsions is known. Suitable diesel engines are, for example, large turbocharged two-stroke diesel engines (e.g., those described in WO 2010/145652 or WO 2010/105620) or two-stroke diesel engines (e.g., those described in DE 19747247 or DE 19747240). Diesel engines can be used in stationary land engines (generators), railway locomotives, automobiles, trucks, inland waterway vessels, or ocean-going vessels. Large two-stroke diesel engines can be used as prime movers in power plants or ocean-going vessels.

Emulsification of fuel and water can be achieved by applying mechanical shear energy, such as in stirred vessels, grinding equipment (e.g., ball mills or stirred ball mills), shaking, rotor-stator mixing, turbulence in pipelines conveyed by pumps or gravity, static mixers, and countercurrent mixers. Fuel and water emulsification can also be achieved by circulating the fuel and water through a loop, for example, by pumping them from the bottom of a tank to the top and then pouring them onto the surface of the tank contents. Pre-stirring may be performed before fuel and water circulation, but is not required.

The emulsifier package may contain different components, such as quaternary ammonium surfactants, a first nonionic surfactant, and a second nonionic surfactant. To emulsify fuel and water, some components may be added to the fuel, and some components may be added to the water, followed by emulsification. Therefore, the different components of the emulsifier package can be combined during the preparation of the fuel emulsion. Preferably, all components of the emulsifier package are premixed before emulsification. Preferably, all components of the emulsifier package are added to the fuel or water simultaneously before emulsification. The invention also relates to a fuel that powers a diesel engine using a fuel emulsion, wherein the fuel comprises an emulsifier package.

Emulsification can be carried out at temperatures ranging from 0 to 100°C, or from 10 to 90°C, or from 20 to 50°C.

Emulsification can be carried out at pressures of 0.5 to 20 bar or 1 to 10 bar.

The time between the preparation of the fuel emulsion and its combustion in the diesel engine can be less than 24 hours, 6 hours, 1 hour, 45 minutes, 30 minutes, 15 minutes, 10 minutes, 5 minutes or 1 minute.

Various devices for emulsifying fuel and water in diesel engines are known, for example, WO 2016/064722, WO90/12959, US 4,388,893 or WO 00/53916.

Example

Quaternary ammonium salt A: N,N-dimethyl-N-hexyldecylamine quaternized with propylene oxide and polyisobutylene succinic acid, wherein the polyisobutylene succinic acid is obtained from succinic acid and polyisobutylene (Mn is about 1000 g/mol); 50 wt% in 2-ethylhexanol.

Nonionic A: An ethoxylated fatty acid amide formed from fatty acids and ethanolamine, a clear liquid with a hydroxyl value of approximately 150 mg KOH/g.

Nonionic B: Castor oil ethoxylate, a clear liquid with a hydroxyl value of approximately 150 mg KOH/g.

Nonionic C: fatty alcohol alkoxylate, curing temperature is about 18°C, kinematic viscosity is 30 ^mm² /s (40°C, ASTM D445).

Additive D: Commercial fuel additive, a reaction product of amines, polyethylene polyamine and polyisobutylene succinic anhydride (40-60% by weight) in C10 hydrocarbons and aromatic hydrocarbons (40-60% by weight).

Additive E: Commercial fuel additive, dimethylaminopropylamine polyisobutylene succinimide in 25-50% by weight of hydrocarbon solvent.

Additive F: Commercial fuel additive, polyisobutylene succinamide of dimethylaminopropylamine.

Additive G: Commercial diesel additive, propoxylated dimethylaminopropylamine polyisobutylene succinamide.

Solvent A: A mixture of C11-14 hydrocarbons (n-alkanes, isoalkanes, cyclic hydrocarbons, and up to 25% aromatics) with approximately 50% C14-18 hydrocarbons (n-alkanes, isoalkanes, cyclic hydrocarbons, and up to 25% aromatics), a clear liquid with a boiling range of 178-285°C and a freezing point below 30°C.

Example 1—Emulsion Stability

The emulsifier packets were prepared by mixing the emulsifiers shown in Table 1 to obtain a liquid mixture of emulsifiers. The sample used to test emulsion stability contained 40 ml each of diesel oil and distilled water, along with the emulsifier packets at a given treatment ratio (see Table 1). The diesel oil was a clear liquid, free of additive packets, and had a density of approximately 0.83 to 0.85.

The emulsion is prepared by shaking the sample in a graduated cylinder on a shaker at 20°C with a lift of 125 mm and a lift rate of 10 lifts for 5 seconds. After shaking stops, the graduated cylinder is allowed to stand for up to 30 minutes. The amount of separated aqueous phase is determined. For example, if 8 ml of separated aqueous phase is detected in an 80 ml total volume sample, it corresponds to 90% emulsion stability. If no separated aqueous phase is detected, it corresponds to 100% emulsion stability.

Table 1: Emulsion stability (concentration, expressed as % by weight, relative to diesel treatment ratio)

Example 2—Corrosion Protection of Steel

Emulsifier package EP-1 was prepared by mixing 10 wt% quaternary ammonium salt A, 60 wt% nonionic A and 30 wt% nonionic C.

The corrosion protection performance of emulsifier package EP-1 on steel was tested according to DIN ISO 7120A. Marine diesel fuel had a density of approximately 890 kg/ ^m³ at 15°C, a viscosity of approximately 7 ^mm² /s (ISO 3104, at 40°C), and a sulfur content of approximately 0.2% by weight. The sample contained marine diesel fuel and distilled water in a 50:50 weight ratio, with an optional treatment ratio of 0.1% by weight of emulsifier package EP-1, based on marine diesel fuel. Cylindrical steel shuttles were immersed at 60°C for 24 hours, and then rusting was observed.

Steel shuttles immersed in an emulsion without EP-1 showed obvious signs of rust. Steel shuttles immersed in an emulsion containing EP-1 showed no signs of rust. Therefore, the emulsifier pack reduced corrosion.

Example 3—Corrosion Protection of Copper

The corrosion protection performance of emulsifier package EP-1 on copper was tested according to DIN ISO 2160A. The sample contained marine diesel fuel and distilled water in a 50:50 weight ratio as in Example 2, and optionally 0.1% by weight of emulsifier package EP-1, based on marine diesel fuel. The copper plate was immersed at 80°C for 3 hours, and then the rusting was observed.

Copper plates immersed in emulsion without an emulsifier packet showed obvious signs of rust. Copper plates immersed in emulsion containing an emulsifier packet did not show any signs of rust. Therefore, the emulsifier packet reduced corrosion.

Example 4—Preventing Sedimentation

40 ml of the marine diesel fuel used in Example 2 was mixed with 40 ml of distilled water, and optionally with emulsifier packet EP-1. A black precipitate immediately formed in the sample, which was filtered off through filter paper (Macherey-Nagel MN 126/70, 0.2 mm thick, 70 g/ ^m² ). The amount of residue on the filter paper was determined after 24 hours.

The sample without the emulsifier packet produced 36.8 g of wet filter residue. The sample with the emulsifier packet produced only 5.5 g of wet filter residue. Therefore, the emulsifier packet reduced the amount of sediment and improved filterability.

Example 5—Additive Packet

The emulsifier package is prepared by mixing emulsifiers as shown in Table 2 to obtain a liquid mixture of emulsifiers.

The samples used to test emulsion stability were prepared by mixing the additive package with diesel fuel. For all experiments in Table 2, the amount of emulsifier used was 0.05%, based on the total volume of the emulsion (including fuel and water).

The diesel fuel used is marine diesel of the DMA type according to DIN ISO 8217, which is clear liquid diesel, without additive packs, and has a density of about 0.83 to 0.85.

The emulsion was prepared in 10 seconds at 7500 rpm at room temperature using a Silverson L5 high-shear laboratory emulsifier based on the rotor-stator principle.

Then, place the emulsified sample into a graduated cylinder and allow it to stand for up to 30 minutes. Determine the amount of the separated aqueous phase. For example, if 8 ml of the separated aqueous phase is detected in an 80 ml total volume sample, it corresponds to 90% emulsion stability. If no separated aqueous phase is detected, it corresponds to 100% emulsion stability. The values are given in Table 2.

Table 2: Additive Packaging (all amounts are in weight %) and Emulsion Stability

Example 6—Diesel Type

The additive packages were prepared using various DMA diesel fuel types as described in Example 5, and their emulsion stability was tested. The results are summarized in Table 3. The DMA marine diesel fuel types tested were:

DMA-1: Dark brown, density (15℃) is about 885 kg/ ^m³ , kinematic viscosity at 40℃ is 4.9 cSt, pour point is -9℃.

DMA-2: Clear, uniform color marking, density (15℃) of approximately 886 kg/ ^m³ , kinematic viscosity at 40℃ of 5.1 cSt, pour point of -21℃.

DMA-3: Clear, with uniform color markings, density (15℃) of approximately 865 kg/ ^m³ , kinematic viscosity at 40℃ of 4.2 cSt, and pour point of -9℃.

DMA-4: Light brown, clear, density (15℃) approximately 887 kg/ ^m³ , kinematic viscosity at 40℃ 6.0 cSt, pour point 12℃.

Table 3: Additive Packaging (all amounts are in weight %) and Emulsion Stability

Claims (28)

1. A fuel emulsion for powering a diesel engine, comprising... -water, - Fuel, and - Emulsifier package containing quaternary ammonium surfactants, and At least two nonionic surfactants selected from fatty amide ethoxylates, castor oil ethoxylates, and ethoxylated fatty alcohols. 2. The fuel emulsion of claim 1, wherein the emulsifier package comprises at least 60% by weight of a nonionic surfactant. 3. The fuel emulsion according to claim 1 or 2, wherein the quaternary ammonium surfactant is a reaction product obtained by means of: - A quaternizable nitrogen compound containing at least one quaternizable amino group is reacted with a quaternizing agent, which converts the at least one quaternizable amino group into a quaternary ammonium group. -The quaternizing agent is a combination of a hydrocarbon epoxide and a free hydrocarbon-substituted polycarboxylic acid. 4. The fuel emulsion according to claim 3, wherein the quaternizable amino group is a tertiary amino group. 5. The fuel emulsion according to claim 1 or 2, wherein the emulsifier comprises 1 to 40% by weight of a quaternary ammonium surfactant. 6. The fuel emulsion according to claim 1 or 2, wherein the fuel emulsion comprises 0.05 to 0.5% by weight of an emulsifier packet, based on fuel. 7. The fuel emulsion according to claim 6, wherein the fuel is diesel oil. 8. The fuel emulsion according to claim 1 or 2, wherein the fuel emulsion is an oil-in-water emulsion. 9. The fuel emulsion according to claim 1 or 2, wherein the fuel emulsion comprises 50 to 80% by weight water. 10. The fuel emulsion according to claim 1 or 2, wherein the fuel is marine fuel. 11. The fuel emulsion according to claim 10, wherein the marine fuel is selected from marine gas oil, marine diesel oil, intermediate fuel oil, marine fuel oil or heavy fuel oil. 12. The fuel emulsion according to claim 11, wherein the marine fuel is selected from intermediate fuel oil with a maximum viscosity of 380 centipoise and has <3.5% sulfur by weight. 13. The fuel emulsion according to claim 11, wherein the marine fuel is selected from intermediate fuel oil with a maximum viscosity of 180 centipoise and has <3.5% sulfur by weight. 14. The fuel emulsion according to claim 11, wherein the marine fuel is selected from low-sulfur intermediate fuel oil with a maximum viscosity of 380 centipoise and has <1.0% sulfur by weight. 15. The fuel emulsion of claim 11, wherein the marine fuel is selected from low-sulfur intermediate fuel oil with a maximum viscosity of 180 centiliter and has <1.0% sulfur by weight. 16. The fuel emulsion according to claim 11, wherein the marine fuel is selected from low-sulfur marine gas oil having a sulfur content of <0.1% by weight, which is commonly used in European ports and anchorages in accordance with the EU Sulfur Directive 2005/33/EC. 17. The fuel emulsion according to claim 11, wherein the marine fuel is selected from ultra-low sulfur marine gas oil, also known as ultra-low sulfur diesel, having a sulfur content of up to 0.0015 by weight. 18. The fuel emulsion of claim 11, wherein the marine fuel is selected from marine fuels of the ISO-F-DMX, DMA, DFA, DMZ, DFZ or DFB categories conforming to DIN ISO 8217, or ISO-F RMA, RMB, RMD, RME, RMG or RMK categories. 19. The fuel emulsion according to claim 11, wherein the marine fuel is selected from distilled marine diesel or residual marine diesel. 20. The fuel emulsion of claim 10, wherein the fuel contains less than 1% by weight of sulfur. 21. The fuel emulsion of claim 10, wherein the fuel contains less than 0.5% by weight of sulfur. 22. The fuel emulsion of claim 10, wherein the fuel contains less than 0.2% by weight of sulfur. 23. The fuel emulsion of claim 10, wherein the fuel contains less than 0.1% by weight of sulfur. 24. A method for powering a diesel engine with a fuel emulsion, comprising the step of preparing the fuel emulsion by emulsifying fuel and water in the presence of an emulsifier packet as described in any one of claims 1-23. 25. An emulsifier package for emulsifying fuel and water, comprising: - Quaternary ammonium surfactants, obtained by reacting a quaternizable nitrogen compound containing at least one quaternizable amino group with a quaternizing agent, wherein the quaternizing agent converts at least one quaternizable amino group into a quaternary ammonium group, wherein the quaternizing agent is a combination of a hydrocarbon epoxide and a free hydrocarbon-substituted polycarboxylic acid. - At least two nonionic surfactants selected from fatty amide ethoxylates, castor oil ethoxylates, and ethoxylated fatty alcohols. 26. The emulsifier package according to claim 25, wherein the quaternizable amino group is a tertiary amino group. 27. The emulsifier package of claim 25, comprising 1 to 40% by weight of a quaternary ammonium surfactant. 28. The emulsifier package according to any one of claims 25-27, comprising at least 60% by weight of at least two nonionic surfactants.