DK169386B1 - Additive distillate fuel oil - Google Patents

Description

in DK 169386 B1

The present invention relates to an additive containing distillate fuel oil which boils in the range of 120 ° C to 500 ° C and has a wax content of at least 0.3% by weight at a temperature of 10 ° C below the growth temperature.

5

Mineral oils containing paraffin wax, such as the distilled fuels used as diesel fuel and heating oil, have the property of becoming less liquid as the temperature of the oil drops. This decrease in fluidity is due to the fact that wax crystal1 in -10 refers to plate-like crystals, which eventually form a sponge-like mass that encloses the oil, where the temperature at which the wax crystals begin to form is called the point of cloudiness and the temperature at which the wax prevents the oil from being poured, called the floating point.

15

It has long been known that various additives act as lowering point agents when mixed with waxy mineral oils. These compositions modify the size and shape of the wax crystals and reduce the cohesive forces between the crystal and the wax and the oil in such a way that the oil remains liquid at a lower temperature and thus can be poured and capable of passing through coarse filters.

The literature describes various floating point lowering agents, 25 and several of which are in commercial use. In e.g. U.S. Patent No. 3,048,479 is taught about the use of copolymers of ethylene and Cj-Cg vinyl esters, e.g. vinyl acetate, as floating point lowering agents for fuels, in particular heating oils, diesel fuel and jet fuel. Also known are floating point lowering polymeric hydrocarbon compounds based on ethyl one and higher α-olefins, e.g. propyl and. U.S. Patent No. 3,252,771 relates to the use of Cjg-Cig-ft olefins polymers with aluminum trichloride / alkyl halide catalysts as flow point lowering agents in distilled fuels of the "broad boiling" type which are easy to treat and available in United States in the 35 early 1960s.

In the late 1960s and early 1970s, greater emphasis was placed on improving the filterability of oils at temperatures between the cloud point and the floating point determined by the tighter DK 169386 B1 2 test (IP 309/80) for cold filter clogging point (CFPP), and Many patents have since been issued relating to additives to improve the fuel performance of this test. U.S. Patent No. 3,961,916 teaches the use of a mixture of copolymers to control the size of the wax crystals. In British Patent No. 1,263,152, it is proposed that the size of the wax crystals may be controlled by using a copolymer with a lower degree of s in the chain branching.

It is also in e.g. UK Patent No. 1,469,016 has been proposed that the copolymers of di-n-alkyl fumarates and vinyl acetate previously used as floating point lowering agents in lubricating oils can be used as co-additives with ethylene / vinyl acetate copolymers in the treatment of high distilled fuels. final boiling points 15 to improve their low temperature flow properties.

It has also been proposed to use additives based on olefinic / maleic anhydride copolymers. Eg. is used in US Patent No. 2,542,542 copolymers of defines such as octadecene and maleic anhydride esterified with an alcohol such as 1aurylal carbon as flow point lowering agents and in UK Patent No. 1,468,588 copolymers of C22 Similarly, in Japanese Patent Publication No. 5,654,037, 25 olefin / maleic anhydride copolymers which have reacted with amines are used as floating point lowering agents in olefinic and maleic anhydride esterified with behenylal carbonate as co-additives for distilled fuels.

In Japanese Patent Publication No. 5,654,038, the derivatives of olefin / maleic anhydride copolymers are used in conjunction with conventional 30-point improving agents for intermediate distillates such as ethylene-vinyl acetate copolymers. Japanese Patent Publication No. 5,540,640 discloses the use of olefin / maleic anhydride copolymers (not esterified) and states that the olefins used should contain more than 20 carbon atoms to achieve CFPP activity. In UK Patent Publication No. 2,192,012, mixtures of certain esterified olefin / maleic anhydride copolymers and low molecular weight polyethylene are used, the esterified copolymers being ineffective when used as the only additives.

DK 169386 B1 3

The enhancement of CFPP activity obtained in these patents by the addition of the additives is achieved by modifying the size and shape of the wax crystals formed to produce mostly needle-like crystals, which generally have a particle size 5 of 10,000 nm or greater, typically from 30,000 to 100,000 nm. When operating in low-temperature diesel engines, these crystals do not pass through the paper fuel filters of vehicles, but form a permeable cake on the filter, which allows the liquid fuel to pass, after which the wax crystals will dissolve as the engine and fuel are heated, which solution can be the main fuel is heated by recycled fuel. However, a build-up of wax can block the filters, leading to start-up problems with diesel vehicles and problems in early driving in cold weather, and it can also lead to failure of heating systems.

It has now surprisingly been found that wax-containing wax crystals sufficiently small at low temperatures to pass through the main filters of paper typically used in 20 diesel engines can be obtained by the addition of certain additives.

Thus, the present invention relates to an additive-containing desti 1-lathe fuel oil which boils in the range of 120 to 500 ° C and having a wax content of at least 0.3% by weight at a temperature of 10 ° C below the growth incipient temperature, which fuel oil is characterized by an additive is used which causes the wax crystals at this temperature to have an average particle size of less than 4000 nm.

The fuel growth temperature (WAT) of the fuel is measured by differential scanning calorimetry (DSC). In this test, a small fuel sample (25 microliters) is cooled at 2 ° C / minute along with a reference sample with similar thermal capacity but which will not precipitate wax in the temperature range of interest (such as kerosene). An exotherm is observed as crystallization begins in the sample. The WAT of the fuel can e.g. is measured by the extrapolation method on a Mettler ΤΑ 2000B different! el scanning calorimeter.

The wax content of the fuel is determined from the DSC trace by integrating the area enclosed by the baseline and the exotherm down to the specified temperature. The calibration has previously been performed on a known amount of crystallizing wax.

5 The average particle size of the wax crystal is measured by analyzing a scanning electron micrograph of a fuel sample at a magnification of between 4000 and 8000 times and measuring the longest dimension of at least 40 out of 88 points on a pre-fixed grid.

We find that assuming the average size is less than 4000 10 nm, the wax will begin to pass through the typical paper filters used in diesel engines, along with the fuel, although we prefer the size to be below 3000 nm, more preferably below 2000, and still more preferably below 1500 nm, most preferably below 1000 nm, where the real benefits of passing the crystals through the 15 paper fuel filters are obtained. The actual achievable size depends on the original nature of the fuel as well as the nature and amount of the additive used, but we have found that it is possible to obtain these sizes and smaller sizes.

The possibility of obtaining such small wax crystals in fuels results in significant advantages in diesel engine operation. This can be demonstrated by pumping stirred fuel through a diesel filter paper used in a VW Golf or Cummins diesel engine at 8 to 15 ml / second and 1.0 to 2.4 liters per second. per minute 25 square meters of filter surface area at a temperature which is at least 5 ° C below the wax appearance temperature and at least 0.5% by weight of the fuel present in the form of solid wax. Both the fuel and the wax are considered to pass successfully through the filter if one or more of the following criteria is met: (i) When 18-20 liters of fuel has passed through the filter, the pressure drop across the filter does not exceed 50 kiloPascal (kPa), preferably 25 kPa; more preferably 10 kPa, most preferably 5 kPa.

(Ii) At least 60%, preferably at least 80%, more preferably at least 90% by weight of the wax present in the original fuel, as determined by the DSC test described above, is found to be present in the fuel, which leaves the filter.

(Iii) While 18-20 liters of fuel is pumped through the filter, the flow rate always remains above 60% of the initial flow rate and preferably above 80%.

5 The amount of crystals passing through the vehicle filter and the operating benefits that arise from small crystals are highly dependent on the crystal length, although the crystal shape is also significant. We find that dice-shaped crystals tend to pass more easily through the filters than flat crystals, and when they do not fit, they provide less resistance to fuel flow. Nevertheless, the preferred crystal shape is a flat shape, which in principle allows more wax to settle as the temperature drops and more wax therefore precipitates before reaching the critical crystal length than is the case with a crystal of the same length. in dice form.

The fuels of the present invention have unique advantages over known distilled fuels whose cold flow properties have been enhanced by the addition of conventional additives. The fuels also have improved cold start capability at low temperatures, which is not based on hot fuel recycling to remove unwanted wax deposits. Furthermore, the wax crystals tend to remain in suspension rather than settle and form wax layers in storage tanks, as is the case with 25 fuels treated with traditional additives and this provides advantages in distribution. Furthermore, the fuel has often improved operation in the cold climate chassis dynamometer test compared to the fuel containing traditional additives. In many cases, the fuel has also improved CFPP capability.

30

Distilled fuel within the general class of fuels boiling from 120 ° C to 500 ° C varies substantially in boiling point properties, n-alkane distributions and wax content. Fuels from Northern Europe generally have lower final boiling points and cloudiness points than the fuels in Southern Europe. The wax content is generally greater than 1.5% (at 10 ° C below WAT). Similar fuels from other countries around the world vary in the same way, taking into account the climate, but the wax content also depends on the crude oil source. A fuel derived from a crude oil from the Middle East is likely to have a lower wax content than one derived from the waxy crude oils, such as the crude oils from China and Australia.

The extent to which it is possible to obtain very small crystals depends on the nature of the fuel itself, and in some fuels it is not possible to produce the extremely small crystals required by the present invention. However, if this situation arises, the fuel properties can be modified so that it is possible to obtain such small crystals by e.g. adjusting the refining conditions and the mixture so that suitable additives can be used.

The additives we prefer to use are compounds of the general formula: 15 A. X— R1

C

S> S> sY-R2 where -Y-R2 represents SoJ 'NR2 R2, -SO3 (_) {+) HNR1R2, -SO3 (") (+) h2NR1R2, -SO3 (') (+) H, NR2, -SO, NR1R2 or -SO-R2; -X-R1 is -Y-R2 or -CONR1R, -CO2 '^ NR ^ R1, -CoJ' ^ HNR ^ R1, -CO ^ '^ HgNRV, - CO 0 (_) (+) H3 NR1, -R2-C00R1, -NR ^ COR1, rW, -rVoR1, -rV, -N (COR ^) R1 or (+) Nr | r2; -Z (_) represents S0 R 2 and R 3 represent all alkyl, alkoxyalkyl or polyalkoxyalkyl containing at least 10 carbon atoms in the main chain; 35 3 R represents hydrocarby and each R may be the same or different, 2 and R is nothing or represents C 1 to C 6 alkylene, and in: DK 169386 B1 7

A

C

C 5 is the carbon-carbon bond (CC bond) either a) ethylenically unsaturated when A and B may be alkyl, alkenyl or substituted hydrocarbyl groups, or b) a part of a cyclic structure which may be aromatic , polynuclear aromatic or cycloaliphatic, it is preferred that XR and YR between them contain at least 3 alkoxy, alkoxyalkyl or polyalkoxyalkyl groups.

The ring atoms of such a cyclic compound are preferably carbon atoms, but may, however, include an N, S or O ring atom to form a heterocyclic compound.

Examples of an aromatic based compound from which the additives can be prepared are 20

ISLAND

(2 '25 ^ 0' 0

The aromatic group of the compound may be substituted.

30

Alternatively, they can be obtained from polycyclic compounds, which are those having two or more ring structures which can take different forms. They may be (a) condensed benzene structures, (b) condensed ring structures where none or all of the rings are benzene, (c) rings bonded together "end-to-end", (d) heterocyclic compounds, (e) non-aromatics ring systems or partially saturated ring systems or (f) three-dimensional ring structures.

DK 169386 B1 8

Condensed benzene structures from which the compounds can be derived include, e.g. naphthalene, anthracene, phenanthrene and pyrene.

The condensed ring structures where none or all of the rings are benzene include, e.g. Azules, Indene, Hydroindene, Fluorene, Diphenylene. Compounds where the rings are joined end-to-end include e.g. diphenyl. Suitable heterocyclic compounds from which the additives can be derived include, e.g. Quinoline, Pyridine, Indole, 2: 3 dihydroindole, benzofuran, coumarin, isocoumarin, 10 benzothiophene, carbazole and thi odi phenylamine. Suitable non-aromatic ring systems or partially saturated ring systems include decal in (decahydronaphthalene), o: -Pinen, cadine, bornylene. Suitable 3-dimensional compounds include e.g. norbornene, bicycloheptane (norbornane), bicyclooctane and bicyclooctene.

15

The two substituents X and Y must be must be attached to ring atoms adjacent to each other in the ring when there is only one ring, or to ring atoms adjacent to each other in one of the rings where the compound is polycyclic. In the latter case, this means that if naphthalene is to be used, these substituents cannot be attached to the 1.8 or 4.5 positions, but must be attached to the 1,2-, 2,3-, 3,4-, 5.6, 6.7 or 7.8 positions.

These compounds are reacted to form esters, amines, amides, 25 semesters / half amides, half ethers or salts used as the additives. Preferred additives are the salts of a secondary amine containing a hydrogen and carbonaceous group or groups containing at least 10 carbon atoms, preferably at least 12 carbon atoms. Such amines or salts can be prepared by reacting the aforementioned acid or anhydride with an amine or by reacting a secondary amine derivative with carboxylic acids or anhydrides. Water removal and heating are usually required to prepare the amides from the acids. Alternatively, the carboxylic acid may be reacted with an alcohol containing at least 10 carbon atoms, or a mixture of an alcohol and an amine.

The hydrogen and carbonaceous groups in the substituents are preferably hydrocarbyl groups, although halogenated hydrocarbyl groups can be used, preferably only with a small content of halogen atoms (e.g. chlorine atoms), e.g. less than 20% by weight. The hydrocarbyl groups are preferably aliphatic, e.g. alkylene. They are preferably unbranched. Unsaturated hydrocarbyl groups, e.g. alkenyl may be used, but they are not preferred.

5

The alkyl groups preferably contain at least 10 carbon atoms, preferably from 12 to 22 carbon atoms, e.g. from 14 to 20 carbon atoms, and are preferably unbranched or branched at the 1- or 2-positions. If branching exists in more than 20% of all the chain chains, the branches must be methyl. The other hydrogen and carbonaceous groups may be shorter, e.g. less than 6 carbon atoms, or may contain at least 10 carbon atoms if desired. Suitable alkyl groups include methyl, ethyl, propyl, hexyl, decyl, dodecyl, tetradecyl, eicosyl and docosyl (behenyl). Suitable alkylene groups include hexylene, octylene, dodecylene and hexadecylene, but these are not preferred.

In the preferred embodiment, wherein the intermediate is reacted with a secondary amine, one of the substituents will preferably be an amide 20 and the other will be an amine or a alkyl ammonium salt of the secondary amine. The particularly preferred additives are the amides and amine salts of secondary amines.

To obtain the fuel of the present invention, these additives are commonly used with other additives, and examples of the other additives include those compounds called "comb" polymers which have the general formula:

30 c T C

D H J H

__ ^ I _ 'I

1 '_ «Ct E GJ m [k lJ n where D = R, CO.OR, 0C0.R, R'CO-OR or OR E = H or CH3 or D or R'

G = H or D

10 m = 1.0 (homopolymer) to 0.4 (molar ratio) J = H, R ', aryl or a heterocyclic group, R'C0 * OR K = H, CO.0R', OCO-R ', OR', COgH L = H, R ', CO-OR', OCO-R ', aryl, CO 2 H 5 n = 0.0 to 0.6 (molar ratio) R> c10 R'> Cj

Another monomer can be terpolymerized, if necessary.

When these other additives are copolymers of α-olefins and maleic anhydride, they can be conveniently prepared by polymerizing the monomers without solvent or in a solution of a hydrocarbon solvent such as heptane, benzene, cyclohexane or white oil at a temperature. usually in the range of 20 ° C to 150 ° C, and usually promoted by a peroxide type or azotype catalyst such as benzoyl peroxide or azo-diisobutyrnitrile under a blanket of an inert gas such as nitrogen or carbon dioxide to exclude oxygen. It is preferred, but not essential, to use equimolar amounts of the olefin and maleic anhydride, although molar amounts in the range of 2: 1 to 1: 2 are suitable. Examples of defines which can be copolymerized with maleic anhydride are: 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene.

The copolymer of the olefin and the maleic anhydride can be esterified by a suitable technique, and although it is preferred that the maleic anhydride is at least 50¾ esterified, it is not essential. Examples of alcohols that may be used include n-decan-1-ol, n-dodecan-1-ol, n-tetradecan-1-ol, n-hexadecan-1-ol, n-octadecan-1-ol. The alcohols may also include up to 1 methyl branch per chain, e.g. 1-methylpentadecan-1-ol, 2-methyltridecan-1-ol. The alcohol may be a mixture of normal and single methyl branching alcohols. Each alcohol can be used to esterify copolymers of maleic anhydride and any of the olefins.

35 It is preferred to use pure alcohols instead of the commercially available all alcohol breaths, but if mixtures are used, R * refers to the average number of carbon atoms in all the cooling group and if alcohols containing a branching at 1- or 2-style1, R * refers to the unbranched chain skeletal segment of the alcohol. When mixtures are used, it is important that a maximum of 15% of the f ^ groups have the value R * + 2. The choice of the alcohol will, of course, depend on the choice of the olefin copolymerized with the maleic anhydride such that 1,5 R + R is in the range of 18 to 38. The preferred value of R + R1 may depend on the boiling point properties of the fuel in which the additive should be used.

These "comb" polymers may also be fumarate polymers and copolymers, such as the compounds described in our European Patent Applications Nos. 153,176, 153,177, 85,301,047 and 85,301,048. Other suitable "comb" polymers are the polymers and copolymers of α-olefins and the esterified copolymers of styrene and maleic anhydride.

Examples of other additives which can be used with the cyclic compound are the polyoxyalkylene esters, ethers, esters / ethers and mixtures thereof, in particular those additives containing at least one, preferably at least 2, unbranched, C groups and a polyoxyalkylene glycol group having a molecular weight of from 20 to 5000, preferably from 200 to 5000, wherein the alkyl group in the polyoxyalkylene englycol group contains from 1 to 4 carbon atoms. These materials are disclosed in European Patent No. 61,895 B. Other such additives are disclosed in U.S. Patent No. 4,491,455.

The preferred esters, ethers or esters / ethers useful in the present invention can be depicted structurally by the formula: R-O (A) -O-R "30 where R and R" are the same or different and can be be i) n-alkyl ii) n-alkyl-C (= O) iii) n-alkyl-O-C (= O) iv) n-alkyl-O-C (= O) - (CH 2 ) nC (= 0) - wherein the alkyl group is unbranched and saturated and contains from 10 to 30 carbon atoms, and A represents the polyoxyalkylene segment of the glycol wherein the alkylene group contains from 1 to 4 carbon atoms such as polyoxymethylene, polyoxyethylene or the polyoxytrimethyl moiety, which is substantially unbranched; any degree of branching with lower alkyl side chains (such as in polyoxypropylene glycol) can be tolerated, but it is preferred that the glycol be substantially unbranched, A may also contain nitrogen.

Suitable glycols are generally the substantially unbranched polyethylene glycols (PEG) and polypropylene glycols (PPG) having a molecular weight of about 100 to 5000, preferably from ca. Esters are preferred, and fatty acids containing 10 to 30 carbon atoms are useful for reaction with the glycols to form the 15 ester additives, and it is preferred to use a C18-C24 fatty acid, especially behenic acids. The esters can also be prepared by esterifying polyethoxylated fatty acids or polyethoxylated alcohols.

Polyoxyalkylene diesters, diethers, ethers / esters and mixtures thereof 20 are suitable as additives where the diesters are preferred for use in distillates having a narrow boiling range, although smaller amounts of mono ethers and monoesters may also be present and often formed in the manufacturing process. It is important for the ability of the additive that a substantial amount of the coolant is present. Particularly preferred are 25 stearic and behenic acid esters or polyethylene glycol, polypropylene glycol or polyethylene / polypropylene glycol mixtures.

The additives used may also contain the ethyl monounsaturated, flow-enhancing ester copolymers. The unsaturated monomers, which may be copolymerized with ethyl one, include unsaturated mono and diesters of the general formula:

C = C

Wherein Rg represents hydrogen or methyl, Rg represents an -OOCRg group, wherein Rg represents hydrogen or a branched or branched C1-6 alkyl group, usually a C1-C6 alkyl group and preferably a C1-C6 group. represents an -COORg group wherein Rg has the meaning previously defined but is not hydrogen and R7 is hydrogen or -COORg as defined above. The monomer, when Rg 15 and Ry represent hydrogen and Rg represents -OOCRg, includes vinyl alcohol esters of Cj-Cgg mon monocarboxylic acids, usually Cj-Cjg mono-carboxylic acids and preferably Cg-Cgg-monocarboxylic acids, usually CCig C -Cg-monocarboxylic acids. Examples of vinyl esters which can be copolymerized with ethylene include vinyl acetate, vinyl propionate and vinyl butyrate or isobutyrate, with vinyl acetate being preferred. When used, we prefer that the copolymers contain from 5 to 40% by weight of the vinyl ester, more preferably from 10 to 35% by weight of the vinyl ester.

They may also be mixtures of two copolymers, such as those described in U.S. Patent No. 3,961,916. It is preferred that these copolymers have an average number molecular weight as measured by vapor phase osmometry of from 1000 to 10,000, preferably from 1000 to 5000.

The additives used may also contain other polar compounds, either ionic or non-ionic, which in fuels have the ability to act as wax crystal growth inhibitors. Polar, nitrogenous compounds have been found to be particularly effective when used with the glycol esters, ethers or esters / ethers. These polar compounds are generally amine salts and / or amides formed by reacting at least one mole of hydrocarbyl substituted amines with one mole of hydrocarbyl acid containing from 1 to 4 carboxylic acid groups, or anhydrides thereof; esters / amides containing from 30 to 300 carbon atoms can be used, preferably from 50 to 150 carbon atoms. These nitrogen compounds DK 169386 B1 14 are described in US Patent No. 4,211,534. Suitable amines are usually long chain, primary, secondary, tertiary or quaternary C 2 -C 4 O amines or mixtures thereof, but shorter chain amines can be used provided that the nitrogen compound in question is oil soluble and therefore generally contains from 30 to 300 carbon atoms. Preferably, the nitrogen compound contains at least one unbranched C8-C24 alkyl segment.

Suitable amines include primary, secondary, tertiary or quaternary amines, but secondary is preferred. Tertiary and quaternary amines can only form amine salts. Examples of amines include tetradecylamine, cocoamine, hydrogenated number gamin and the like. Examples of secondary amines include dioctacetylamine, methylbehenylamine and the like. Amine mixtures are also suitable and many 15 amines derived from natural materials are mixtures. The preferred amine is a secondary, hydrogenated number gamin of the formula HNRjRg, wherein R 1 and R 2 represent all cooling groups derived from hydrogenated sebum fat composed of approx. 4% C14, 31% C16 and 59% Clg.

Examples of suitable carboxylic acids (and their anhydrides) for the preparation of these nitrogen compounds include cyclohexane-1,2-di-carboxylic acid, cyclohexene-1,2-di-carboxylic acid, cyclopentane-1,2-di-carboxylic acid, naphthalene dicarboxylic acid and similar. Generally, these acids will have approx. 5-13 carbon atoms in the cyclic moiety.

Preferred acids useful in the present invention are benzendi carboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid. Phthalic acid and its anhydride are particularly preferred. The particularly preferred compound is the amide-amine salt which is formed by the reaction of 1 mole of phthalic anhydride with 2 moles of di-hydrogenated tallow amine. Another preferred compound is the diamide which is formed by dehydrating this amide-amine salt.

Hydrocarbon polymers can also be used as part of the additive combination to produce the fuels of the invention. These 35 can be reproduced by the following general formula: DK 169386 B1 15 r "

Γτ H UH

1 1 t li - \ c— c-- c — c--

\ I I II

It tj v (h uj w 5

Where T = H or R 'U = Η, T or aryl 10 v = 1.0 to 0.0 (molar ratio) w = 0.0 to 1.0 (molar ratio) where R' represents a normal alkyl group containing more than 10 carbon atoms.

15

These polymers can be prepared directly from ethylenically unsaturated monomers or indirectly, e.g. hydrogenating the polymer prepared from other monomers such as in soprene and butadiene.

A particularly preferred hydrocarbon polymer is a copolymer of ethylene and propylene having an ethylene content which is preferably between 50 and 60% (w / w).

The amount of additive required to prepare the distilled fuel oil of the present invention will vary depending on the fuel, but is generally from 0.001 to 0.5% by weight, e.g. from 0.01 to 0.1% by weight (active substance) based on the weight of the fuel. The additive may conveniently be dissolved in a suitable solvent to form a concentrate of from 20 to 30% by weight, e.g. from 30 to 80% by weight in the solvent. Suitable solvents include kerosene, aromatic naphthas, mineral lubricants, etc.

The present invention is illustrated by the following 35 examples in which the size of the wax crystals in the fuel is measured by placing samples of fuel in 57 g bottles in cold boxes kept at 8 ° C above the fuel cloud point for 1 hour while the fuel temperature stabilizes. The box is then cooled at 1 ° C per hour down to the test temperature, where it is then kept.

A pre-made filter carrier which consisted of a 10 mm diameter sintered ring surrounded by a 1 mm wide annular 5 metal ring supporting a 200 nm silver membrane filter, which filter is held in place by two vertical needles, is then applied to a vacuum unit. A vacuum of at least 80 kPa is applied and the cooled fuel is dripped onto the diaphragm from a clean drip cap until a small dome-shaped puddle just covers the diaphragm.

10 The fuel is slowly dripped to maintain the pool; after approx. 10-20 drops of fuel had been applied, allowing the puddle to drain away leaving a thin, matte layer of damp fuel wax cake on the membrane. A thick layer of wax will not be acceptable to wash and a thin layer can be washed. The optimum layer thickness is a function of the crystal shape where "leafy" crystals need thinner layers than "small-knotted" crystals. It is important that the final cake has a matte appearance. A "shiny" cake indicates excess residual fuel and crystal "smearing" and should be discarded.

The cake is then washed with a few drops of methyl ethyl ketone, which is allowed to drain completely. The process is repeated a number of times.

When the wash is done, the methyl ethyl ketone will disappear very quickly leaving a "brilliant-math white" surface which will turn gray upon application of another drop of methyl ethyl ketone.

25

The washed sample was then placed in a cold desiccator and kept there until coated in the SEM assay. It may be necessary to keep the sample cool to preserve the wax, in which case it should be stored in a cold box prior to transfer (in a suitable sample transfer container) to the SEM assay to avoid crystal formation on the sample surface.

During coating, the sample should be kept as cold as possible to minimize the damage to the crystals. Electrical contact with the object table 35 is best provided with a holding screw which presses the ring to the side of a well in the object table which is designed so that the sample surface may lie in the instrument focal plane. An electrically conductive coating can also be used. After coating, the hook frames are obtained in the conventional manner on the scanning electron microscope. The Fotomi hook frames DK 169386 B1 17 were analyzed to determine the average crystal size by attaching a transparent 88-point sheet (as spots) to the cuts in a regular, evenly spaced grid of 8 rows and 11 columns for a suitable microgram. The magnification should be such that only a few of the largest crystals are affected by more than one spot, and a magnification of 4000 - 8000 times has proven to be suitable.

At each grid point where the stain touches a crystal whose shape can be easily delimited, the crystal can be measured. A measure of "scattering" in the form of a Gaussian standard deviation of the crystal length using Bessel correction is also taken.

The wax content before and after the filter was measured using a differential scanning calorimeter DSC (such as the du Pont 9900 series), which is capable of producing an image having an area of approx. o 15 100 cm / 1% wax in the fuel with a noise-induced instrument output variation with a standard deviation of less than 2% of the mean output signal.

The DSC was calibrated using an additive to form 20 large crystals, which were assuredly removed from the filter, investigated this calibration fuel at the test temperature of the equipment, and measured the growth temperature of the thus-depleted fuel on the DSC. The tank fuel and post-filtration fuel samples to be examined are then analyzed on the DSC, and for each fuel, the area above baseline down to the growth temperature of the calibration fuel was determined.

DSC area for Dröven after filtering. , -,

The ratio of light DSC area for the tank sample x 100/30 is the percentage of wax left after the filter.

The cloud point of the distilled fuels was determined by the cloud standard test (IP-219 or ASTM-D 2500), and other initial crystallization targets are the Growth 1 Visibility Point Test (WAP) (ASTM D.3117-72) and the Growth 1 Visibility Temperature (WAT). ) is measured by differential scanning calorimetry using a Mettler ΤΑ 2000B differential scanning calorimeter.

The ability of the fuel to pass through a main filter in a diesel car DK 169386 B1 18 was determined in an apparatus consisting of a typical main filter in a diesel car placed in a standard assembly in a fuel line; The Bosch type used in a 1980 VW Golf diesel passenger car and a Cummins FF105 used in the Cummins NTC engine series are 5 appropriate. A reservoir and feed system capable of supplying half of a normal fuel tank with fuel connected to a fuel injection pump as used in the VW Golf was used to draw fuel through the filter from the tank at a constant flow rate as in the car. Instruments 10 are provided to measure the pressure drop across the filter, the flow rate from the injection pump and the unit temperatures. Containers are provided to receive the pumped fuel, both the "injected" fuel and surplus fuel.

15 During the test, the tank was filled with 19 kg of fuel and was leak tested. When this was satisfactory, the temperature was stabilized at an air temperature of 8 ° C above the fuel cloud point. The unit was then cooled at 3 ° C / hour to the desired test temperature and kept there for at least 3 hours to stabilize the fuel temperature. The tank is shaken vigorously to completely disperse the wax present; a sample is taken from the tank and 1 liter of fuel is removed through a sampling point on the discharge line immediately after the tank and returned to the tank. The pump is restarted at the pump speed per minute. 25 minutes equal to revolutions per minute. pump speed at a road speed of 110 km / h (110 kph). In the case of the VW Golf, this is 1900 rpm. which corresponds to an engine speed of 3800 rpm. minute. Pressure drop across the filter and fuel flow rate from the injection pump are measured until the fuel is exhausted, typically from 30 to 35 minutes.

Provided that the fuel supply to the injectors can be kept at 2 ml / sec. (excess fuel will be about 6.5 - 7 ml / sec) the result is "PASSED". A decrease in feed fuel flow to the injectors indicates a "BORDER LINE" result; no power a "FAILED".

A "PASSED" result is typically associated with an increasing pressure drop across the filter, which can rise to as much as 60 kPa. Generally, considerable amounts of wax must pass through the filter in order for such a result to be achieved. A "GOOD PASSAGE" is characterized by a process in which the pressure drop across the filter does not exceed 10 kPa and is the first indication that most of the wax has passed through the filter, an excellent result having a pressure drop below 5 5 kPa.

In addition, fuel samples are taken from the "surplus" fuel and the "injection food" fuel, ideally every 4 minutes during the test. These samples are compared with samples from the tank prior to the DSC test to determine the proportion of wax passed through the filter. Samples are also taken from the fuel prior to the test and SEM samples are prepared from them after the test to compare wax crystal size and type with actual capacity.

The following additives were used.

The additive 1Ν, dial-dialkylammonium salt of 2-dialkylamidobenzene sulfonate, wherein the 20alkyl groups are nCjgjg prepared by reacting 1 mole of cyclic anhydride of orthosulfobenzoe with 2 moles of di- (hydrogenated) tallow amine in a xylene solvent of 50% (w / w). The reaction mixture was stirred between 100 ° C and the reflux temperature. The solvent and chemicals should be stored as dry as possible so that the anhydride is not hydrolyzed.

The product was analyzed by 500 MHz nuclear magnetic resonance spectroscopy, confirming that the structure was: 30 o C - N (CH 2 - (CH 2) 14/16 - CH 3) 2

(cyt

SO3 (-) (+) nH2 (CH2 - (CH2) i4 / 16 -CH3) 2 DK 169386 B1 20

Additive 2

A copolymer of ethyl one and 17% by weight vinyl acetate had a molecular weight of 3500 and a side chain branching rate of 8 methyl groups per 100 methylene groups measured at 500 MHz NMR.

5

Additive 3

A styrene-dialkyl maleate copolymer prepared by esterification of a styrene-maleic anhydride copolymer (mole ratio 1: 1) with 2 moles of a mixture of C12H250H and C1-6OH (mole ratio 1: 1) per mole of anhydride-10 group (a small excess, 5% alcohol was used) using p-toluenesulfonic acid as a catalyst (1/10 mole) in xylene solvent to give a molecular weight (mean number of s) of 50,000 and a content of 3% (w / w) unreacted alcohol.

Additive 4

The di-cool the ammonium salts of 2-N, N-dialkylamidobenzoate prepared by mixing 1 mole of phthalic anhydride with 2 moles of di-hydrogenated tallow amine at 60 ° C.

The results were as follows:

Example 1 Fuel properties.

25 Cloud point -14 ° C

Growth income temperature -18.6 ° C

Initial boiling point 178 ° C

20% 230 ° C

90% 318 ° C

30 ° C boiling point 355 ° C

Wax contents at -25 ° C 1.1 wt% 250 ppm of each of the additives 1, 2 and 3 were added to the fuel and the test temperature was -25 ° C. The wax crystals were found to have a length of 1200 nm and over 90% by weight of the wax passed through the Cummins FF105 filter.

During the test, the passage of wax was further detected by observing the pressure drop across the filter, which increased only by 2.2 kPa.

DK 169386 B1 21

Example 2

Example 1 was repeated and the wax crystal size was found to be 1300 nm and the maximum final pressure drop across the filter was 3.4 kPa.

5

Example 3

Fuel characteristics.

Cloud point 0eC

10 Growth incidence temperature -2.5 ° C Initial boiling point 182 ° C

20% 220 ° C

90% 354 ° C

SI boiling point 385 ° C

Wax contents at the test temperature 1.6 wt% 250 ppm of each of the additives 1, 2 and 3 were used and the wax crystal size was found to be 1500 nm, and approx. 75% by weight of the wax had passed through the Bosch 145434106 filter at the test temperature of -8.5 ° C. The maximum pressure drop across the filter was 6.5 kPa.

Example 4

Example 3 was repeated and found to give a wax crystal size of 2000 nm, and ca. 50% by weight of the wax passed through the filter, giving a maximum pressure drop of 35.3 kPa.

Example 5

The fuel used in Example 3 was treated with 400 ppm Additive 1 and 100 ppm of a mixture of Additive 2 and tested 30 as in Example 3 at -8 ° C, at which temperature the wax content was 1.4% by weight. The wax crystal size was found to be 2500 nm and 50 wt% of the wax passed through the filter with a maximum final pressure drop of 67.1 kPa.

Example 6 (Comparative Example)

The fuel used in Example 3 was treated with 500 ppm of a mixture of 4 parts of additive 4 and 1 part of additive 2 and tested at -8 ° C, where the wax crystal size was found to be 6300 nm, and 22% by weight of the adult had passed through the filter.

This example is one of the very best examples in the prior art where there is no crystal passage.

5

A scanning electron micrograph of the wax crystals formed in the fuels of Examples 1 to 6 is reproduced in Figures 1 to 6.

Examples 1-4 show, therefore, that crystals can pass through the filter reliably and that excellent ability at cold temperature can be extended to much higher wax content of the fuel than has hitherto been practiced, and also at temperatures further below the growth point of growth. than 15 have so far been able to practice. This applies without regard to the fuel system, such as the possibility that recycled fuel from the engine can heat the feed fuel taken from the fuel tank, the ratio of feed fuel flow to recycled fuel, the ratio of main filter surface area 20 to feed fuel flow, and the size and position of the prefilter.

Examples 1 to 3 show that for the tested filters, crystal lengths of less than about 1 1800 nm in a significantly improved fuel capacity.

Example 7 In this example, Additive 1 was added to a distilled fuel having the following properties: 30

Initial boiling point 180 ° C

20% 223 ° C

90% 336 ° C

Final boiling point 365 * C

35 Growth 1Secure temperature -5.5 ° C

Cloud point -3.5 ° C

For comparison, the following additives were also added to the distilled fuel: DK 169386 B1 23

Additive Å: A mixture of ethylene / vinyl acetate copolymers, one of which was additive 2 (1 part by weight) and the other (3 parts by weight) had a vinyl acetate content of 36% by weight, a molecular weight (average number) of 2000, a side chain branching of 2 and 3 methyl groups per 100 methyl one-5 groups measured at 500 MHz NMR.

Additive B: A mixture of additives 4 and 2, the molar ratio of which was 4: 1.

Additive C: The dibehenate of a polyethylene glycol bl breath with an average molecular weight of 600.

Additive D: An ethylene / propylene copolymer in which the ethylene content was 56 wt% and the average number molecular weight was approx. 60,000.

The additives were added in the amounts shown in the following table and the tests were performed according to PCT, the details of which are as follows:

Programmed cooling test fPCT)

This is a slow cooling test designed to correlate with the pumping of a stored heating oil. The cold flow properties of the fuel containing the additives are determined by the PCT as follows: 300 ml of fuel is cooled linearly with TC / h to the test temperature and then the temperature is kept constant. After two hours at the test temperature, approx. 20 ml of the surface layer upon aspiration to prevent the test from being affected by the abnormally large wax crystals which tend to form on the oil-air interface during cooling. Wax, which is precipitated in the bottle, is dispersed by gentle stirring and a CFPPT® filter unit is inserted. The tap is opened to apply a vacuum of 500 mm Hg and closes when 200 ml of fuel has passed through the filter into the graduated receiving vessel: A "PASSED" is indicated if the 200 ml is collected within 10 seconds through a given mesh size , or a "FAILED" if the flow rate is low, indicating that the filter has been blocked.

35 The mesh number passed at the test temperature is indicated.

(1) CFPPT - Cold Filter Clogging Point Test (CFPPT) described in detail in "Journal of the Institute of Petroleum", vol.52, no.510, June 1966, pp.173-185.

DK 169386 B1 24

Table

Finest PCT mask passed at -11 ° C Additive (mole ratio dl 150 ppm 250 ppm (active ingredient) A 100 200 4 60 120 1 200 350 10 4/2 (4/1) 100 350 1/2 ( 4/1) 350 350 4 / C (9/1) 150 250 1 / C (9/1) 250 350 15 4 / D (9/1) 150 350 1 / D (9/1) 350 350

Thus, it appears that when only one additive is added, the best 20 results are obtained with additive 1, and when pairs of additives are used, the best results are obtained when additive 1 is one of the pair.

Example 8 The fuel used in this example had the following characteristics: (ASTH-D86)

Initial boiling point 190 * C

20% 246 ° C

90% 346 ° C

Final boiling point 374 “C

Growth pathway temperature -1.5 * C Cloudiness point + 2.0eC

35

It was treated with 1000 parts per million active ingredients of the following additives: (E) A mixture of additive 2 (1 part by weight) and additive 4 (9 parts by weight).

DK 169386 B1 25 (F) The commercial ethylene vinyl acetate copolymer additive sold by Exxon Chemicals as ECA 5920.

(G) A mixture of: 5 1 part additive 1

1 part additive 3 1 part additive D 1 part additive K

(H) The commercial ethylene vinyl acetate copolymer additive sold by Amoco as 2042E.

(I) The commercial ethylene vinyl propionate copolymer additive sold by BASF as Keroflux 5486.

(J) No additive (K) The reaction product from the reaction between 4 moles of hydrogenated number of gamine and 1 mole of pyromellitic anhydride. The reaction was carried out without solvent at 150 ° C with stirring under nitrogen for 6 hours.

The following performance characteristics of these fuels were then measured: (i) The fuel's ability to pass through the diesel fuel main filter at -9 ° C and the percentage of wax passing through the filter with the following results:

Additive Time to failure% wax passing 30 E 11 minutes 18-30% F 16 minutes 30% G Did not fail 90-100% H 15 minutes 25% I 12 minutes 25% 35 j 9 minutes 10% (ii) Pressure drop over main filter are plotted against time and the results are shown graphically in Figure 7.

(Iii) Wax precipitation in the fuels was measured by cooling fuel in a graduated measuring container containing 100 ml, and this peak level corresponds to 100% of the height of the fuel. The vessel was cooled at rc / hour from a temperature which was preferably 10 ° C above the fuel cloud point, but not less than 5 ° C above the fuel cloud point, until the test temperature which was maintained for the prescribed time. The test temperature and the temperature equalization time depended on the application, ie. diesel fuel and heating oil. The test temperature is generally at least 5 ° C below the cloud point, and the minimum 10 minimum cold settling time at the test temperature is at least 4 hours. Preferably, the test temperature should be at least 10 ° C or more below the fuel cloud point and the temperature equalization period should be 24 hours or more.

After the temperature equalization period, the measuring vessel was examined and the amount of wax crystal precipitation was measured visually as the height of any layer of wax above the bottom of the vessel (0 ml) and expressed as a% of total volume (100 ml). Clear fuel can be seen over the precipitated wax crystals, and this form of measurement is often sufficient to assess the 20 wax precipitation. Often, the fuel is unclear over a precipitated wax crystal layer, or it can be seen that the wax crystals are visibly closer as they approach the bottom of the container. In this case, a more quantitative method of analysis is used. Here the top 5% (5 ml) of the fuel is carefully sucked up and stored, the next 45% is sucked and discarded, 25 the next 5% is sucked and stored, the next 35% is sucked and discarded and finally the 10% is collected at the bottom after heating to dissolve the wax crystals. These stored samples will therefore be referred to as top, middle and bottom samples respectively. It is important that the applied vacuum to remove the samples is rather low, ie. 200 mm of water pressure, 30 and that the top of the pipette is placed precisely on the surface of the fuel to avoid flow in the liquid which could interfere with the concentration of wax in different layers in the container. The samples are then heated to 60 ° C for 15 minutes and examined by differential scanning calorimetry (DSC) as described elsewhere in this specification.

35 The DSC technique involves using a machine such as the Dupont 9900 series or Mettler ΤΑ 2000B. The latter machine was used here. A 25 μΐ sample was placed in the sample cell and plain kerosene in the reference cell, after which they were cooled at 22 ° C / minute from 60 ° C to at least 10 ° C above growth temperature (WAT), but preferably 20 ° C above this. temperature, then cooled at 2 ° C / minute to approx. 20 ° C below the growth stage of the appearance temperature. A reference must be made to the non-precipitated, uncooled, treated fuel. The degree of 5 wax precipitation then correlates with the growth of the 1-seed temperature (or / ^ WAT = WAT in the precipitated sample - WAT initially). Negative values indicate dewaxing of the fuel and positive values indicate wax enrichment upon settling. The wax content can also be used as a measure of precipitation in these samples. This is illustrated by% wax or 10 wax (a% wax =% wax in the precipitated sample -% wax initially), and again negative values indicate dewaxing of the fuel, and positive values indicate wax enrichment upon precipitation. The wax content is obtained by measuring the area under the DSC curve down to a specified temperature.

The fuel was cooled at TC / hr from + 10 ° C to -9 ° C and was cooled for 48 hours prior to testing. The results were as follows:

Visual wax _ Growth body temperature data l * C) 20 Additive precipitate Upper 5% Middle 5% Lower 10% E unclear -10.80 -4.00 -3.15 all the way Closer at the bottom F 50% clear -13.35 - 0.80 -0.40 25 over G 100% -7.85 -7.40 -7.50 H 35% clear -13.05 -8.50 +0.50 over I 65% clear 30 over J 100% semi-gel -6.20 -6.25 -6.40 (the results are also shown graphically in Figure 8).

35 DK 169386 B1 28

Initial Growth Vision Temperature Growth Path 1 Visibility Temperature (non-precipitated f ° Cl (precipitated samples! _ 5 fuel! Upper 5% Middle 5% Lower 10% E -6.00 -4.80 +2.00 + 2.85 F - 5.15 -8.20 +4.35 +4.75 G -7.75 -0.10 +0.35 +0.25 H -5.00 -8.05 -3.50 +4.50 10 J -6.20 0.00 -0.05 -0.20 (note that a significant decrease in growth increment temperature can be achieved by the most effective additive (G)).

% wax (precipitated samples) _ 15 Upper 5% Middle 5% Lower 10% E -0.7 + 0.8 + 0.9 F -0.8 + 2.1 + 2.2 G% 0.0 +0 , 3 + 0.1 H -1.3 -0.2 +1.1 20 J -0.1% 0.0% 0.1 (Note:% wax is measured by extending the original baseline and measuring the area from the growth incense temperature to -25 T. Here, a calibration 25 has previously been performed on a known amount of the crystallizing wax).

These results showed that when the crystal size was reduced in the presence of the additives, the wax crystals precipitated relatively quickly. Eg. unprocessed fuels when cooled below their cloud point tend to show slight wax crystal precipitation because the plate-like crystals intervene and cannot fall freely in the liquid, and a gel-like structure is built up, but when a floating point enhancer is added, For example, the crystals may be modified so as to have less tendency to form plates and tend to form needles of sizes in the vicinity of a micrometer number, which can move freely in the liquid and settle relatively quickly. This wax crystal precipitation can cause problems in storage tanks and car systems. Unexpectedly, a concentrated wax layer can be pulled off, especially when the fuel level is low or the tank is disturbed (eg when a car is running around corners) and filter blocking can take place.

If the wax crystal size can be further reduced to below 10,000 nm, the crystals settle relatively slowly and there may be a wax antibody precipitate which offers advantages in fuel function compared to a fuel with precipitated wax crystal. If the wax crystal size can be reduced to less than approx. 4000 nm, the tendency of the crystals to settle is almost eliminated within the time the fuel is stored. If the crystal size is reduced to the preferred size, the wax crystals remain suspended in the fuel for the many weeks needed in some storage systems, and the settling problems are effectively eliminated.

(Iv) The following results are obtained with respect to CFPP:

Additive CFPP Temperature (8C1 CFPP Lowering E) E -14 11 20 F -20 17 G -20 17 H -20 17 I -19 16 J -3 25 (v) The average crystal size was found to be:

Additive Size (nanometer! 30 E 4400 F 10400 G 2600 H 10800 I 8400 35 j Thin plates over 50000.

Claims (5)

30 DK 169386 B1 An additive containing distillate fuel oil which boils in the range of 120 ° C to 500 ° C and having a wax content of at least 0.3% by weight at a temperature of 10 ° C below the wax appearance temperature, characterized by the use of an additive which causes the wax crystals at this temperature has an average particle size of less than 4000 nm. An additive-containing distillate fuel oil according to claim 1, characterized in that the wax crystals have an average particle size of less than 3000 nm. An additive-containing distillate fuel oil according to claim 1, characterized in that the wax crystals have an average particle size of less than 2000 nm. An additive-containing distillate fuel oil according to claim 1, characterized in that the wax crystals have an average particle size of less than 1500 nm. An additive-containing distillate fuel oil according to claim 1, characterized in that the wax crystals have an average particle size of less than 1000 nm. 25 30 35