fuel composition

Abstract

A fuel composition comprising a base fuel and an additive mixture, wherein the base fuel comprises a renewable fuel component, and wherein the additive mixture comprises: (i) a first additive comprising a long-chain carboxylic acid polyamine; and (ii) a second additive comprising an ionic or nonionic oil-soluble polar organic nitrogen-containing compound having a single nitrogen atom per molecule; wherein the weight ratio of the first additive to the second additive is in the range of 6:1 to 2:1. The additive mixture is capable of improving the low-temperature flow properties (cloud point and CFPP) of the renewable fuel component.

Description

Technical Field

[0001] This invention relates to fuel compositions comprising renewable fuel components. In particular, the fuel compositions of this invention have improved low-temperature flow properties. Background Technology

[0002] Renewable fuel components (such as renewable diesel) can be manufactured by hydrogenating triglyceride fats (e.g., from vegetable or animal oils) to remove the glycerol backbone and produce fatty acids, which then produce alkane molecules upon further hydrogenation. Fatty acid esters can be processed in the same way, hence the name "hydrogenated esters and fatty acids" or "HEFA".

[0003] Fatty acid synthesis in biological systems typically produces even-numbered molecules between C14 and C24. Without additional hydrocracking, HEFAs (Herbaceous Alkane Fuels) with boiling points corresponding to diesel fuels meeting the EN15940 specification for alkane fuels are rich in n-alkanes or n-alkane molecules.

[0004] However, mixtures of n-alkanes within this carbon range typically crystallize at ambient temperatures common during the winter months. Crystallization temperature can be measured using "cloud point" tests such as ASTM D2500-05, ASTM D5771-05, ASTM D5772-05, ASTM D5773-05, or ASTM D7397-08. Below the cloud point, n-alkanes crystals are typically flat and plate-like in appearance and can cause fuel shortage problems due to clogged fuel filters by stacking themselves. One method for measuring the low-temperature flow properties of diesel fuel is the cold filter plugging point (CFPP) laboratory test according to standard test methods EN116, IP309, and ASTM D6371.

[0005] To avoid low-temperature flow problems with crystallized n-alkanes, low-temperature flow improvers are often used in diesel fuel produced from mineral / crude oil sources during winter. These additives typically do not change the cloud point temperature, but they cause a decrease in CFPP temperature (improvement) by interfering with the crystal growth mechanism of n-alkanes. These crystals now have a modified morphology, with an elongated / needle-like appearance, and maintain an open structure when stacked, allowing the fuel to flow at temperatures well below the cloud point temperature.

[0006] However, the very high concentrations of n-alkanes found in renewable diesel produced by the HEFA process mean that low-temperature flow improvement additives used for mineral diesel are generally ineffective in improving the low-temperature flow properties of HEFA.

[0007] The low-temperature flow properties of HEFA can be alternatively improved by introducing energy-intensive steps into the manufacturing process, by hydrocracking, and by isomerizing n-alkanes into isoalkanes. These isoalkanes crystallize at colder temperatures than n-alkanes, and thus the more isomerized HEFA exhibits improved low-temperature flow properties (lower cloud point and lower CFPP).

[0008] The aim is to reduce the total carbon footprint of renewable fuel components (such as HEFA) and lower manufacturing costs. The inventors have now discovered that by using a specific combination of additives in fuel compositions containing renewable fuel components (such as HEFA), the low-temperature flow properties (both cloud point and CFPP) of the fuel composition can be improved, while reducing the need for stringent hydrocracking / isomerization steps during the manufacture of renewable fuel components (such as HEFA). Summary of the Invention

[0009] According to the present invention, a fuel composition comprising a base fuel and an additive mixture is provided, wherein the base fuel comprises renewable fuel components, and wherein the additive mixture comprises:

[0010] (i) a first additive, the first additive comprising a long-chain carboxylic alkyl polyamine; and

[0011] (ii) A second additive comprising an ionic or nonionic oil-soluble polar organic nitrogen-containing compound having a single nitrogen atom per molecule.

[0012] The weight ratio of the first additive to the second additive is in the range of 6:1 to 2:1.

[0013] According to the present invention, the use of the additive mixture in a fuel composition for reducing the cloud point and cold filter plugging point (CFPP) of the fuel composition is also provided, wherein the fuel composition comprises a base fuel and an additive mixture, wherein the base fuel is a renewable fuel component, and wherein the additive mixture comprises (i) a first additive comprising a long-chain carboxylic acid alkyl polyamine and (ii) a second additive comprising an ionic or nonionic oil-soluble polar organic nitrogen-containing compound having a single nitrogen atom per molecule.

[0014] The weight ratio of the first additive to the second additive is in the range of 6:1 to 2:1.

[0015] According to the present invention, a method for reducing the cloud point and cold filter plugging point of a fuel composition is also provided, wherein the method includes adding an additive mixture to the fuel composition, wherein the fuel composition comprises a base fuel, wherein the base fuel comprises a renewable fuel component, wherein the additive mixture comprises (i) a first additive comprising a long-chain carboxylic acid alkyl polyamine and (ii) a second additive comprising an ionic or nonionic oil-soluble polar organic nitrogen-containing compound having a single nitrogen atom per molecule.

[0016] The weight ratio of the first additive to the second additive is in the range of 6:1 to 2:1.

[0017] It has been found that by using specific combinations of additives in fuel compositions containing HEFA, the low-temperature flow properties of both HEFA and the fuel compositions can be improved, particularly in terms of cloud point and CFPP reduction, while reducing the need for stringent hydrocracking / isomerization steps during HEFA manufacturing. In particular, it has been found that the use of specified additive combinations improves the low-temperature flow properties of HEFA and HEFA-containing fuel compositions, enabling them to meet European winter fuel specifications. Attached Figure Description

[0018] Figure 1 Typical low-temperature flow properties of automotive gas oil (AGO) (0% to 30% FAME) are shown when treated with conventional low-temperature flow improvers and untreated. In AGO treated with conventional low-temperature flow improvers, CFPP is reduced (improved), with minimal or no change in cloud point.

[0019] Figure 2 Typical low-temperature flow properties of HEFA (0% FAME) are shown when treated and untreated with the low-temperature flow improvement additive mixtures disclosed herein. Figure 1 Unlike the AGO example shown, HEFA treated with the low-temperature flow improvement additive mixture disclosed herein exhibits a reduction (improvement) in both cloud point and CFPP.

[0020] Figure 3 The average CFPP performance benefit of adding KF4990 alone in HEFA is shown in comparison with the average incremental change observed when the first and second additives are combined in different ratios.

[0021] Figures 4A to 4D Compositional analysis of the concentration of n-alkanes and the ratio of isoalkanes to n-alkanes in renewable diesel blends with and without the low-temperature flow improvement additive mixtures disclosed herein, and the correlation of these parameters with low-temperature flow properties (cloud point and cold filter plugging point).

[0022] Figure 5The figure is a graphical representation of the experimental data presented in Table 1, which shows the improvement of the low-temperature flow properties (cloud point and cold filter plugging point) of HEFA in the presence of the low-temperature flow improvement additive mixture disclosed herein. Detailed Implementation

[0023] The fuel composition of the present invention comprises a mixture of base fuel and additives, wherein the base fuel comprises renewable fuel components.

[0024] It has been advantageously found that the additive mixtures used herein reduce both the cloud point and cold filter plugging point of the fuel composition. In doing so, renewable alkane fuel components with lower isomerization ratios can be utilized, thus avoiding the need for energy-intensive hydroisomerization steps in the production of renewable fuel components and reducing the overall carbon footprint of renewable alkane fuels.

[0025] As used herein, the term "cloud point" for fuel refers to the temperature at which the heaviest n-alkanes become insoluble and precipitate from the fuel, giving it a cloudy appearance. The cloud point can be measured by any suitable test method, such as ASTM D2500, D5771, D5772, D5773, D7689, EN3015, and DIN EN ISO 3015. The preferred test method used herein for measuring the cloud point is DIN EN ISO 3015.

[0026] As used herein, the term "cold filter plugging point (CFPP)" for fuel refers to the temperature at or below which a fuel would cause severe limitation as it flows through a filter. CFPP can be measured by any suitable test method, such as ASTM D6371, EN 116, or DIN EN 116. The preferred test method used herein for measuring CFPP is DIN EN 116.

[0027] Both the cloud point and cold filter plugging point are measured and given as temperature (T, here C). The lower the cloud point and cold filter plugging point, the better the low-temperature properties of the fuel.

[0028] In the context of this aspect of the invention, the term "reduction of cloud point and cold filter plugging point" includes any degree of reduction in the cloud point and cold filter plugging point of a fuel composition. The reduction in the cloud point of a fuel composition compared to the cloud point of a similar fuel composition without the specified additive mixture can be about 1°C or higher, preferably 2°C or higher, more preferably 3°C or higher, and especially 4°C or higher. Even a 1°C reduction in the cold filter plugging point is worthwhile because such a reduction allows the material to meet the seasonal specifications of EN 15940 alkane fuels, which would otherwise not be met.

[0029] Adding the specified additive package eliminates the need for isomerization or hydrocracking to increase the isoparaffin to n-paraffin ratio in the C14-C20 HEFA renewable fuel component. Specifically, a 1°C decrease in cloud point is equivalent to a 9.2% increase in the isoparaffin to n-paraffin ratio in the C14-C20 HEFA renewable fuel component, a 2°C decrease is equivalent to a 19% increase, a 3°C decrease is equivalent to a 29.4% increase, and a 4.0°C decrease is equivalent to a 40.5% increase.

[0030] Compared to similar fuel compositions that do not contain the specified additive mixture, the reduction in the cold filter plugging point of the fuel composition may be about 1°C or higher, preferably 2°C or higher, more preferably 3°C or higher, and especially 4°C or higher.

[0031] Adding the specified additive package eliminates the need for isomerization or hydrocracking to increase the isoparaffin to n-paraffin ratio in the C14-C20 HEFA renewable fuel component. Specifically, a 1.0°C reduction in CFPP is equivalent to a 9.2% increase in the isoparaffin to n-paraffin ratio in the C14-C20 HEFA renewable fuel component, a 2.0°C reduction is equivalent to an 18.3% increase, a 3.0°C reduction is equivalent to a 28.4% increase, and a 4.0°C reduction is equivalent to a 39% increase.

[0032] The base fuel used in the fuel compositions of the present invention comprises a renewable fuel component. In one embodiment, the renewable fuel component is present in the fuel compositions herein at a level ranging from 20% v / v to 100% m / m, preferably from 50% v / v to 100% v / v, more preferably from 80% v / v to 100% v / v, and even more preferably from 90% v / v to 100% v / v, based on the total fuel composition.

[0033] The renewable fuel component preferably comprises or consists of the following: hydrotreated vegetable oils, hydrotreated animal fats, hydrotreated fish fats, hydrotreated fish oil, hydrotreated algal oil, hydrotreated microbial oil, hydrotreated wood and / or other plant-based oils, hydrotreated recyclable waste and / or recyclables, or combinations thereof. Preferably, the fresh feedstock for the renewable fuel is selected from vegetable oils / fats, animal fats / oils, fish fats / oils, fats contained in genetically engineered plants, recycled fats from the food industry, and combinations thereof. Hydrotreated vegetable oils or animal fats are an alternative process to esterification for the production of bio-based middle distillate fuels. Hydrotreated renewable middle distillate fuels are also referred to as “hydrotreated vegetable oil fuels,” “hydrotreated renewable diesel,” “renewable fuel,” “renewable diesel,” or “renewable diesel component,” rather than “biodiesel,” and are reserved for fatty acid methyl esters (FAMEs). Chemically, hydrotreated renewable middle distillates are mixtures of alkanes and hydrocarbons, and have very low levels of sulfur and aromatics.

[0034] Preferably, the renewable fuel component used herein is a gas oil derived from hydrotreated vegetable oil (HVO) or a mixture of gas oils derived from hydrotreated vegetable oil (HVO).

[0035] The isomerization ratio of renewable fuels (such as hydrotreated renewable middle fractions) can be, for example, at least 50% or at least 60%. The isomerization ratio is defined as the sum of isoalkanes (wt%) divided by the sum of alkanes (wt%). Higher isomerization ratios generally improve low-temperature properties, but such hydrotreated renewable middle fractions consume more resources during their production. Isomerization ratios exceeding 80% can be achieved, but this may not be necessary in the context of this invention, given the improved low-temperature properties achieved through the use of specified additive mixtures. Preferably, the isomerization ratio of renewable fuels (such as hydrotreated renewable middle fractions) is less than 69%, yielding advantageous ranges of 50% to 69% and 60% to 69%, respectively.

[0036] Because hydrotreated renewable middle distillates are hydrocarbons, they can be used as conventional middle distillate fuels. Fatty acid methyl ester specifications (EN 14214, ASTM D6751) do not apply to hydrotreated renewable middle distillates, and therefore there is no volume percentage limit on the amount of hydrotreated renewable middle distillates that can be blended with diesel fuel.

[0037] The base fuel present in the fuel composition may contain approximately 100% renewable fuel or may be a blend of renewable fuel and mineral middle distillate components. When the base fuel contains 100% renewable fuel, the base fuel may contain a mixture of renewable fuel components.

[0038] In one embodiment of this document, the renewable fuel component is present in the fuel composition as a blend with mineral diesel oil (such as EN590 or ASTM D975 refined diesel oil). In this embodiment, the renewable fuel component is preferably present in the fuel composition at a level in the range of 1% v / v to 99% v / v, more preferably 20% v / v to 70% v / v, even more preferably 20% v / v to 50% v / v, and especially in the range of 20% v / v to 30% v / v, based on the total fuel composition.

[0039] Mineral middle distillates are naturally occurring fuel components derived from non-renewable sources. Examples of non-renewable sources include petroleum or shale oil, or combinations thereof. Middle distillates are typically diesel or kerosene fuels. In this invention, mineral middle distillates are preferably mineral diesel. Diesel fuel is any liquid fuel that can be used in a diesel engine and is typically a specific fraction of petroleum fuel oil. The diesel fuel used herein preferably conforms to the EN590 specification for diesel fuel. Mineral diesel can also be referred to as petrochemical diesel, fossil diesel, or petroleum fraction. Mineral diesel may contain atmospheric or vacuum fractions. The fraction may contain cracked gas oil, or a blend of straight-run fractions or thermally cracked or catalytically cracked fractions. The fraction fuel may undergo further processing (such as hydrotreating or other treatments) to improve fuel properties, such as low-temperature flow properties. Typically, mineral diesel contains 10% to 70% by weight of n-alkanes and isoalkanes, 10% to 50% by weight of cycloalkanes, 5% to 30% by weight of monoaromatics, 0% to 11% by weight of diaromatics, and 0% to 5% by weight of other aromatics.

[0040] The preferred mineral diesel used herein is petroleum-derived low-sulfur diesel containing <50 ppm sulfur, such as ultra-low sulfur diesel (ULSD) or zero-sulfur diesel (ZSD). Preferably, the low-sulfur diesel contains <10 ppm sulfur. The preferred petroleum-derived low-sulfur diesel used in this invention typically has a density of 0.81 g / cm³ at 15°C. 3 Up to 0.865 g / cm 3 0.82g / cm 3 Up to 0.85 g / cm 3 More preferably 0.825 g / cm 3 Up to 0.845 g / cm 3 The cetane number (ASTM D613) is at least 51; and the kinematic viscosity at 40°C (ASTM D445) is 1.5 mm. 2 / s to 4.5mm 2 / s, preferably 2.0mm 2 / s to 4.0mm 2 / s, more preferably 2.2mm 2 / s to 3.7mm 2 / s.

[0041] Preferably, the renewable fuel and mineral middle distillate fractions are blended at a volume percentage ratio of less than 95:5, more preferably less than 90:10 (renewable fuel: mineral middle distillate). In one embodiment, the renewable fuel and mineral middle distillate fractions are blended at a volume percentage ratio of 20:80 to 80:20 (renewable fuel: mineral middle distillate). In another embodiment, the renewable fuel and mineral middle distillate fractions are blended at a volume percentage ratio of 20:80 to 60:40.

[0042] Renewable fuel components and mineral middle distillate components are preferably present in the fuel composition at a total level of at least 90% by volume based on the total fuel composition. Other fuel components suitable for diesel engines may also be included in the fuel composition herein, such as Fischer-Tropsch derived alkane gas oil and fatty acid methyl esters (FAME).

[0043] The fuel composition of the present invention comprises an additive mixture as a basic component to improve the low-temperature properties of the renewable fuel component and the final fuel composition. The additive mixture is preferably present at a level of 50 mg / kg to 5000 mg / kg, more preferably 50 mg / kg to 2000 mg / kg, even more preferably 50 mg / kg to 750 mg / kg, and especially 63 mg / kg to 500 mg / kg, based on the weight of the fuel composition.

[0044] The additive mixture comprises (i) a first additive comprising a long-chain carboxylic acid alkylamine; and (ii) a second additive comprising an ionic or nonionic oil-soluble polar organic nitrogen-containing compound; wherein the weight ratio of the first additive to the second additive is in the range of 6:1 to 2:1.

[0045] In a preferred embodiment, the weight ratio of the first additive to the second additive is in the range of 4:1 to 2:1, preferably 3.5:1 to 2.5:1, and even more preferably 3:1 to 2.5:1. In a particularly preferred embodiment herein, the weight ratio of the first additive to the second additive is 3:1.

[0046] The first additive comprises a long-chain alkyl polyamine. Preferably, the long-chain alkyl polyamine is a reaction product of C14-C18 fatty acids with linear, branched, or cyclic alkyleneamines (preferably straight-chain alkyleneamines). In one embodiment, the C14-C18 fatty acids comprise a mixture of linear and branched C14-C18 fatty acids and C18 unsaturated fatty acids. In another embodiment, the C14-C18 fatty acids comprise isooctadecanoic acid, octadecanoic acid, or mixtures thereof, preferably octadecanoic acid. Preferably, the alkyleneamine is an ethyleneamine, especially tetraethylammonium ethyleneamine. In a particularly preferred embodiment herein, the long-chain alkyl polyamine is a reaction product of isooctadecanoic acid or octadecanoic acid, or mixtures thereof, with tetraethylammonium ethyleneamine. In a particularly preferred embodiment, the long-chain alkyl polyamine is a reaction product of octadecanoic acid and tetraethylammonium ethyleneamine.

[0047] The long-chain carboxylic acid alkyl polyamine is preferably present in the first additive at a level of 30% to 60% by weight based on the weight of the first additive. Preferably, the first additive also contains a heavy aromatic solvent, such as naphtha. Preferably, the heavy aromatic solvent is present at a level of 30% to 60% by weight based on the weight of the first additive. Other preferred components in the first additive include naphthalene and 1,2,4-trimethylbenzene.

[0048] The first additive can be obtained from Infineum under the trade name Infineum R536A.

[0049] The second additive comprises an ionic or nonionic oil-soluble polar organic nitrogen-containing compound containing a single nitrogen atom per molecule, wherein the oil-soluble polar organic nitrogen-containing compound is preferably selected from one or more compounds of the following (a) to (c):

[0050] (a) amine salts and / or amides formed by reacting at least one mole of an amine with a hydrocarbon-substituted amine with one mole of a hydrocarbon acid having one to four carboxylic acid groups or its anhydride;

[0051] (b) A compound comprising or including a cyclic ring system having at least two substituents of the following general formula (I) on the ring system.

[0052] -A-NR 1 R 2 (I)

[0053] Where A is an aliphatic hydrocarbon group optionally interrupted by one or more heteroatoms and is straight-chain or branched, and R 1 and R 2 The substituents are identical or different, and each independently is a hydrocarbon group containing 9 to 40 carbon atoms, optionally interrupted by one or more heteroatoms, the substituents being identical or different, and the compound optionally being in the form of its salt; and

[0054] (c) Condensation products of long-chain primary or secondary amines with carboxylic acid-containing polymers.

[0055] Further details for compounds (a), (b), and (c) are provided below: Compound (a)

[0056] (a) An amine salt and / or amide formed by reacting at least one mole of a hydrocarbon-substituted amine with one mole of a hydrocarbon acid having one to four carboxylic acid groups or its anhydride. Esters / amides containing 30 to 300, preferably 50 to 150 total carbon atoms can be used. Suitable amines are typically long-chain C12-C40 primary, secondary, tertiary, or quaternary amines or mixtures thereof, but shorter-chain amines can be used, provided that the resulting nitrogen compound is oil-soluble and therefore typically contains about 30 to 300 total carbon atoms. The nitrogen compound preferably contains at least one straight-chain C8 to C40, preferably C14 to C24 alkyl segment.

[0057] Suitable amines include primary, secondary, tertiary, or quaternary amines, but secondary amines are preferred. Tertiary and quaternary amines can only form amine salts. Examples of amines include tetradecylamine, cocoylamine, and hydrogenated tallow amine. Examples of secondary amines include dioctadecylamine and methyl-betamethamine. Mixtures of amines are also suitable, such as those derived from natural materials. A preferred amine is a secondary hydrogenated tallow amine of the formula HNR1R2, wherein R1 and R2 are alkyl groups derived from hydrogenated tallow fat consisting of approximately 4% C14, 31% C16, and 59% C18.

[0058] Examples of suitable carboxylic acids and their anhydrides for the preparation of nitrogen compounds include cyclohexane-1,2-dicarboxylic acid, cyclohexene-1,2-dicarboxylic acid, cyclopentane-1,2-dicarboxylic acid, and naphthalene-2-dicarboxylic acid, as well as 1,4-dicarboxylic acid comprising dialkylspirobetrolide. Typically, these acids have about 5-13 carbon atoms in the cyclic moiety. Preferred acids that can be used in this invention are phthalic acids, such as phthalic acid, isophthalic acid, and terephthalic acid. Phthalic acids and their anhydrides are particularly preferred. A particularly preferred compound is an amide-amine salt formed by reacting 1 mole of phthalic anhydride with 2 moles of dehydrotallow amine. Another preferred compound is a diamide formed by dehydrating the amide-amine salt.

[0059] Other examples are long-chain alkyl or alkylene-substituted dicarboxylic acid derivatives, such as amine salts of substituted monoamides of succinic acid, examples of which are known in the art and described, for example, in US-A-4,147,520. Suitable amines can be those mentioned above.

[0060] Other examples are condensates, such as those described in EP-A-327,423. Compound (b)

[0061] b) A compound comprising or including a cyclic ring system, wherein the compound has at least two substituents of the following general formula (I) on the ring system.

[0062] -A-NR 1 R 2 (I)

[0063] Where A is an aliphatic hydrocarbon group optionally interrupted by one or more heteroatoms and is straight-chain or branched, and R 1 and R 2 The substituents may be identical or different, and each independently is a hydrocarbon group containing 9 to 40 carbon atoms, optionally interrupted by one or more heteroatoms, and the compound may optionally be in the form of its salt. Preferably, A has 1 to 20 carbon atoms, and is preferably a methylene or polymethylene group.

[0064] As used herein, the term "hydrocarbon group" refers to a group having a carbon atom directly attached to the remainder of the molecule and having hydrocarbon or predominantly hydrocarbon characteristics. Examples include hydrocarbon groups, including aliphatic groups (e.g., alkyl or alkenyl), alicyclic groups (e.g., cycloalkyl or cycloalkenyl), aromatic groups and alicyclic-substituted aromatic groups, as well as aromatic-substituted aliphatic groups and aromatic-substituted alicyclic groups. Aliphatic groups are advantageously saturated. These groups may contain non-hydrocarbon substituents, provided their presence does not alter the predominantly hydrocarbon characteristics of the group. Examples include ketones, halogens, hydroxyl groups, nitro groups, cyano groups, alkoxy groups, and acyl groups. If the hydrocarbon group is substituted, a single (mono) substituent is preferred.

[0065] Examples of substituted hydrocarbon groups include 2-hydroxyethyl, 3-hydroxypropyl, 4-hydroxybutyl, 2-ketopropyl, ethoxyethyl, and propoxypropyl. These groups may also contain atoms other than carbon in a chain or ring originally composed of carbon atoms, or alternatively, atoms other than carbon in a chain or ring originally composed of carbon atoms. Suitable heteroatoms include, for example, nitrogen, sulfur, and preferably oxygen.

[0066] The cyclic ring system may comprise allotropic rings, heterocyclic rings, or fused polycyclic components, or a system in which two or more such cyclic components are connected to each other and the cyclic components may be the same or different. When two or more such cyclic components are present, the substituents of general formula (I) may be on the same or different components, preferably on the same component. Preferably, the cyclic component, or each cyclic component, is aromatic, more preferably a benzene ring. Most preferably, when the preferred substituents are in the ortho or meta position, the cyclic ring system is a single benzene ring, which may optionally be further substituted.

[0067] The ring atoms in one or more cyclic components are preferably carbon atoms, but may include, for example, one or more ring N, S or O atoms, in which case the compound is a heterocyclic compound.

[0068] Examples of such multi-ring components include:

[0069] (i) Fused benzene structures, such as naphthalene, anthracene, phenanthrene, and pyrene;

[0070] (ii) Fused ring structures in which all rings are not benzene or not all rings are benzene, such as azulene, indene, hydrogenated indene, fluorene and dibenzofuran;

[0071] (iii) "End-to-end" rings, such as diphenyl;

[0072] (iv) Heterocyclic compounds, such as quinoline, indole, 2:3 dihydroindole, benzofuran, coumarin, isocoumarin, benzothiophene, carbazole and thiodiphenylamine;

[0073] (v) Non-aromatic or partially saturated cyclic systems, such as naphthanes (i.e., decahydronaphthalene), α-pinene, myristene, and borneol; and

[0074] (vi) Three-dimensional structures, such as norbornene, bicycloheptane (i.e., norbornane), bicyclooctane and bicyclooctene.

[0075] Each hydrocarbon group constituting R1 and R2 in this invention (Formula I) can be, for example, an alkyl group, an alkylene group, a monoalkoxyalkyl group, or a polyalkoxyalkyl group. Preferably, each hydrocarbon group is a straight-chain alkyl group. The number of carbon atoms in each hydrocarbon group is preferably 16 to 40, more preferably 16 to 24.

[0076] Furthermore, preferably, the ring system is substituted by only two substituents of general formula (I), and A is a methylene group.

[0077] Examples of salts of compounds are acetates and hydrochlorides.

[0078] The compounds can be readily prepared by reducing the corresponding amide, which can be prepared by reacting a secondary amine with a suitable acyl chloride; and Compound (c)

[0079] c) Condensations of long-chain primary or secondary amines with carboxylic acid-containing polymers.

[0080] Specific examples include polymers such as those described in GB-A-2,121,807, FR-A-2,592,387 and DE-A-3,941,561; esters of telemer acids and alkanolamines, such as those described in US-A-4,639,256; long-chain epoxide / amine reaction products that may optionally be further reacted with polycarboxylic acids; and reaction products of amines, epoxides and monocarboxylic acid polyesters containing branched carboxylic acid esters, such as those described in US-A-4,631,071.

[0081] Other examples of suitable second additives for use herein include those compounds disclosed in WO93 / 18115 and WO2008 / 113757.

[0082] The preferred second additive used herein is an unsaturated conjugated carboxylic acid compound having the formula HOOC-CH=CH-C(X)=NR, wherein R is a C6 to C22 alkyl group, and wherein X is a hydroxyl or alkoxy group. Preferably, R is a C8 to C18 alkyl group, more preferably a C12 to C18 alkyl group, especially a C13 alkyl group. Preferably, the X group is a hydroxyl group.

[0083] In a particularly preferred embodiment, the second additive comprises branched (Z)-4-oxo-4-(tetrazylamino)-2-butenoic acid (molecular formula: C 17 H 31 NO3). This additive is available from BASF under the trade name Keroflux (RTM) 4990.

[0084] The first additive is preferably present in the fuel composition at a level of 63 ppmw to 2000 ppmw, more preferably 125 ppmw to 1000 ppmw, and even more preferably 188 ppmw to 500 ppmw based on the fuel composition.

[0085] The second additive is preferably present in the fuel composition at a level of 31 ppmw to 2000 ppmw, more preferably 63 ppmw to 1000 ppmw, or even more preferably 63 ppmw to 375 ppmw based on the fuel composition.

[0086] The fuel composition described herein is particularly suitable as a diesel fuel, and due to its excellent low-temperature flow properties, it can be used as a winter-grade diesel fuel for Arctic applications.

[0087] For example, a cloud point of -10°C or lower (EN 23015) or a cold filter plugging point (CFPP) of -20°C or lower (as measured by EN116) is possible for the fuel compositions described herein.

[0088] The diesel base fuel can be any petroleum-derived diesel fuel suitable for internal combustion engines, such as petroleum-derived low-sulfur diesel fuel containing <50 ppm sulfur, for example, ultra-low sulfur diesel (ULSD) or zero-sulfur diesel (ZSD). Preferably, the low-sulfur diesel fuel contains <10 ppm sulfur.

[0089] Preferably, the petroleum-derived low-sulfur diesel oil used in this invention has a density of typically 0.81 g / cm³ at 15°C. 3 Up to 0.865 g / cm 3 0.82g / cm 3 Up to 0.85 g / cm 3 More preferably 0.825 g / cm 3 Up to 0.845 g / cm 3 The cetane number (ASTM D613) is at least 51; and the kinematic viscosity at 40°C (ASTM D445) is 1.5 mm. 2 / s to 4.5mm 2 / s, preferably 2.0mm 2 / s to 4.0mm 2 / s, more preferably 2.2mm 2 / s to 3.7mm 2 / s.

[0090] In one implementation, the diesel base fuel is conventional petroleum-derived diesel.

[0091] Generally, in the context of this invention, fuel compositions may contain fuel additives in addition to the additive mixtures described above. Unless otherwise stated, the concentration of each such additive (active substance) in the fuel composition is preferably up to 10,000 ppmw, more preferably in the range of 5 ppmw to 1,000 ppmw, advantageously 75 ppmw to 300 ppmw, such as 95 ppmw to 150 ppmw. Such additives may be added at different stages of the fuel composition production process; those added to the base fuel at the refinery may, for example, be selected from antistatic agents, pipeline drag reducers, middle distillate flow improvers (MDFI) (e.g., ethylene / vinyl acetate copolymers or acrylate / maleic anhydride copolymers), lubrication enhancers, antioxidants, and wax antisettling agents.

[0092] Fuel compositions may contain detergents, which are agents (suitably surfactants) that can be used to remove and / or prevent combustion-related deposits from accumulating in the engine, particularly in fuel injection systems such as in injector nozzles. Such materials are sometimes referred to as dispersant additives. When a fuel composition contains detergents, the preferred concentration, based on the total fuel composition, is in the range of 20 ppmw to 500 ppmw of active detergent, more preferably 40 ppmw to 500 ppmw, most preferably 40 ppmw to 300 ppmw, or 100 ppmw to 300 ppmw, or 150 to 300 ppmw. Diesel fuel additives containing detergents are known and commercially available. Examples of suitable detergent additives include succinamides of polyolefin-substituted succinimides or polyamines, such as polyisobutylene succinimide or polyisobutylene amine succinamide, aliphatic amines, Mannich bases or amines, and polyolefins (e.g., polyisobutylene) maleic anhydride. Particularly preferred are polyolefin-substituted succinimides, such as polyisobutylene succinimide.

[0093] Other components that can be incorporated as fuel additives include, for example, in combination with detergents, including lubricant enhancers; demisters, such as alkoxylated phenol-formaldehyde polymers; defoamers (e.g., commercially available polyether-modified polysiloxanes); ignition improvers (hexadecane modifiers) (e.g., 2-ethylhexyl nitrate (EHN), cyclohexyl nitrate, di-tert-butyl peroxide, and those disclosed in column 2, lines 27 through 3, lines 21 of US4208190); and rust inhibitors (e.g., propane of tetrapropylene succinate). -1,2-diol half-esters, or polyol esters of succinic acid derivatives having an unsubstituted or substituted aliphatic hydrocarbon group containing 20 to 500 carbon atoms on at least one α-carbon atom, such as pentaerythritol diester of polyisobutylene-substituted succinic acid; corrosion inhibitors; deodorizers; anti-wear additives; antioxidants (e.g., phenols such as 2,6-di-tert-butylphenol, or phenylenediamines such as N,N'-di-sec-butyl-p-phenylenediamine); metal passivators; static dissipative additives; and mixtures thereof.

[0094] This invention is particularly applicable to fuel compositions used in or intended for use in direct injection diesel engines, such as rotary pumps, in-line pumps, unit pumps, electronic unit injectors, or common rail types, or for use in indirect injection diesel engines. The fuel compositions described herein are applicable to heavy-duty and / or light-duty diesel engines, as well as engines designed for on-road or off-road use.

[0095] For suitability to at least the above-described uses, the diesel fuel compositions described herein preferably have one or more of the following characteristics:

[0096] - The kinematic viscosity at 40°C is 1.9 mm. 2 / s or greater, more preferably at 1.9mm2 / s to 4.5mm 2 Within the range of / s;

[0097] - Density is 800 kg / m³ 3 Or larger, more preferably at 800 kg / m 3 Up to 860kg / m 3 , or even better, 800 kg / m 3 Up to 845kg / m 3 Within the range;

[0098] -T95 is 360°C or lower;

[0099] - The cloud point is in the range of 0°C to -13°C, more preferably -5°C to -8°C;

[0100] -CFPP is in the range of -8°C to -30°C, more preferably -15°C to -20°C.

[0101] The present invention is illustrated by the following non-limiting embodiments. Example

[0102] HEFA samples from commercial sources with different low-temperature flow properties were used, in their pure form and binary mixtures, to understand the correlation between hydrocarbon composition and low-temperature flow properties. The distribution of n-chain alkanes and isomerized alkanes with different carbon chain lengths was measured by gas chromatography. Low-temperature flow properties were measured using standard methods for cloud point (DIN EN ISO 3015) and cold filter plugging point (DIN EN 116). Analysis of these data ( Figures 4A to 4D The study revealed a logarithmic relationship between the concentration of n-chain alkanes and their cloud point and cold filter plugging point (CFPP). Similarly, the ratio of iso-alkanes with carbon chain lengths from C14 to C20 to n-chain alkanes exhibited a second-order polynomial relationship with their cloud point and CFPP. These blending rules allow for the formation of binary mixtures of HEFA at target cloud point and CFPP temperatures.

[0103] Example 1

[0104] A binary mixture of highly isomerized 79.4 wt% HEFA (11.6 wt% n-alkane content; isoalkane / n-alkane ratio = 8.05) and low-isomerized 20.4 wt% HEFA (98.0 wt% n-alkane content; isoalkane / n-alkane ratio = 0.02) was blended. Testing confirmed that this mixture exhibited the predicted expected cold filter plugging point (-5°C) and cloud point (-3.4°C).

[0105] Low-temperature flow additives (Infineum R536A from Infineum and Keroflux KF4990 from BASF) were individually blended into the HEFA blends at concentrations ranging from 63 mg / kg to 2000 mg / kg and weight ratios ranging from 1:1 to 3:1 (R536A to KF4990). The low-temperature flow properties of these samples were measured using the same method as described above.

[0106] The results showed that the cold filtration point (CFR) of HEFA could be improved (reduced) by up to 2°C to -7°C, and the cloud point was improved (reduced) by up to 3°C to -6.4°C. An unexpected and favorable observation was that the dose-response was non-linear, with the greatest improvement in CFR achieved at moderate dose rates (<250 mg / kg additive), and the preferred combination of the two additives (R536A and KF4990, 3:1) achieved incremental improvement in CFR compared to a less preferred combination of the two additives (R536A and KF4990, 1:1). Example 2

[0107] A binary mixture of highly isomerized HEFA (11.6% by mass of n-alkane; isoalkane / n-alkane ratio = 8.05) and low isomerized HEFA (98.0% by mass of n-alkane; isoalkane / n-alkane ratio = 0.02) was blended to obtain four blends with cloud points ranging from 0°C to -21°C and cold filter plugging points ranging from 0°C to -22°C.

[0108] Low-temperature flow additives (Infineum R536A from Infineum and Keroflux KF4990 from BASF) were blended into these HEFA blends respectively, and combined with each other according to Table 1.

[0109] The results in Table 1 show that by adding the low-temperature flow additive mixture, the cold filter plugging point of HEFA can be improved (reduced) by up to 2°C, and the cloud point can be improved (reduced) by up to 4°C.

[0110]

[0111] The unexpected and favorable observation was:

[0112] (i) The dose-response is non-linear, achieving maximum improvement in cloud point and cold filtration point at moderate dose rates (250 mg / kg additive; aligned with Example 1);

[0113] (ii) At the preferred ratio of the two additives (375 mg / kg R536A and 125 mg / kg KF4990, 3:1; Example 2E), the incremental improvement in cold filter plugging point was measured to be the same as that of the higher dose of the single additive (750 mg / kg R536A; Example 2C, or 750 mg / kg KF4990; Example 2D).

[0114] (iii) At a fixed dosage rate or preferred ratio of additives, the improvement (reduction) in cloud point and cold filter plugging point depends on the original low-temperature flow properties of the HEFA. For HEFAs with cloud points between -9°C and -14°C and cold filter plugging points between -10°C and -17°C, the maximum improvement (reduction) in cloud point and cold filter plugging point is achieved (e.g., Figure 5 (as shown)

[0115] (iv) At a fixed dosage rate or preferred ratio of the additive, the improvement (reduction) in cloud point and cold filter plugging point leads to the disruption of the previously observed relationship between these low-temperature flow properties and the concentration of n-alkane in HEFA. This in Figure 4A and Figure 4B As illustrated, both the logarithmic coefficient of x (concentration of n-alkane) and the vertical offset are observed to change. This confirms the unexpected and favorable observation in point (iv) above, and demonstrates that the concentration of n-alkane is no longer a valid predictor of the low-temperature flow properties of HEFA in the presence of the example additive.

[0116] (v) At a fixed dosage rate or preferred ratio of additives, the improvement (reduction) in cloud point and cold filter plugging point leads to the disruption of the previously observed polynomial relationship between these low-temperature flow properties and the ratio of iso-alkanes to n-alkanes with C14-C20 carbon chain lengths in HEFA. This in Figure 4C and Figure 4D As illustrated, changes were observed in both the first and second-order coefficients of x (the ratio of iso-alkanes to n-alkanes with C14-C20 carbon chain lengths) and the vertical offset. This confirms the unexpected and favorable observation in point (iv) above, and demonstrates that, in the presence of the example additive, the ratio of iso-alkanes to n-alkanes with C14-C20 carbon chain lengths is no longer a valid predictor of the low-temperature flow properties of HEFA. discuss

[0117] Typically, when no low-temperature flow improvement (CFI) additive is used, it is used in mineral-derived diesel (0% to 30% biodiesel content); Figure 1 ) and HEFA ( Figure 2 A strong linear correlation was found between the cloud point and cold filter point in both samples.

[0118] Adding CFI additives to mineral-derived diesel (0% to 30% biodiesel content) weakens the correlation between cloud point and cold filter plugging point. Figure 1 Example in.

[0119] At reduced temperatures, without the use of CFI additives, and below the cloud point (DIN EN ISO 3015), n-alkane wax crystals in mineral-derived diesel (0% to 30% biodiesel content) rapidly grow into flat, dish-shaped crystals, which clog the filter media in the cold filter plugging test (DIN EN 116) at temperatures close to the cloud point.

[0120] CFI additives added to mineral-derived diesel (0% to 30% biodiesel content) produce wax crystals with long, needle-like shapes that form an open matrix and allow the fuel to continue flowing at temperatures well below the cloud point.

[0121] Further unexpected and favorable observations were observed, namely that the correlation between cloud point and cold filter plugging point was maintained when using the example CFI additives (alone and in combination) in HEFA. Figure 2 This indicates that HEFA has a different and unique mechanism compared to mineral-derived diesel (0% to 30% biodiesel content).

Claims

1. A fuel composition comprising a base fuel and an additive mixture, wherein the base fuel comprises a renewable fuel component, and the additive mixture comprises: (i) a first additive, the first additive comprising a long-chain carboxylic acid alkyl polyamine; and (ii) A second additive comprising an ionic or nonionic oil-soluble polar organic nitrogen-containing compound containing a single nitrogen atom per molecule. The weight ratio of the first additive to the second additive is in the range of 6:1 to 2:

1.

2. The fuel composition according to claim 1, wherein the weight ratio of the first additive to the second additive is in the range of 4:1 to 2:

1.

3. The fuel composition according to claim 1 or 2, wherein the weight ratio of the first additive to the second additive is in the range of 3.5:1 to 2.5:

1.

4. The fuel composition according to any one of claims 1 to 3, wherein the weight ratio of the first additive to the second additive is 3:

1.

5. The fuel composition according to any one of claims 1 to 4, wherein the ionic or nonionic oil-soluble polar organic nitrogen-containing compound is selected from one or more compounds of the following (a) to (c): (a) amine salts and / or amides formed by reacting at least one mole of an amine with a hydrocarbon-substituted amine with one mole of a hydrocarbon acid having one to four carboxylic acid groups or its anhydride; (b) A compound comprising or including a cyclic ring system, said compound having at least two substituents of the following general formula (I) on said ring system. -A-NR 1 R 2 (I) Where A is an aliphatic hydrocarbon group optionally interrupted by one or more heteroatoms and is straight-chain or branched, and R 1 and R 2 The substituents may be identical or different, and each independently is a hydrocarbon group containing 9 to 40 carbon atoms, optionally interrupted by one or more heteroatoms; the substituents may be identical or different, and the compound may optionally be in the form of its salt; and (c) Condensation products of long-chain primary or secondary amines with carboxylic acid-containing polymers.

6. The fuel composition according to any one of claims 1 to 5, wherein the ionic or nonionic oil-soluble polar organic nitrogen-containing compound is an unsaturated conjugated carboxylic acid compound having the formula HOOC-CH=CH-C(X)=NR, wherein R is a C6-C22 alkyl group, and wherein X is a hydroxyl group or an alkoxy group.

7. The fuel composition according to claim 6, wherein R is a C8-C18 alkyl group.

8. The fuel composition according to any one of claims 1 to 7, wherein the long-chain carboxylic acid alkyl polyamine present in the first additive is a reaction product of C14-C18 fatty acids and alkylene polyamines.

9. The fuel composition according to any one of claims 1 to 8, wherein the long-chain carboxylic acid alkyl polyamine present in the first additive is a reaction product of C14-C18 fatty acids and ethylene polyamine.

10. The fuel composition according to any one of claims 1 to 9, wherein the long-chain carboxylic acid alkyl polyamine present in the first additive is a reaction product of C14-C18 fatty acids and tetraethylammonium amine.

11. The fuel composition according to any one of claims 8 to 10, wherein the long-chain carboxylic acid amine present in the first additive is the reaction product of isooctadecanoic acid or octadecanoic acid or a mixture thereof with tetraethylammonium amine.

12. The fuel composition according to any one of claims 1 to 11, wherein the renewable fuel component is a hydrogenated vegetable oil (HVO) derived gas oil or a mixture of hydrogenated vegetable oil (HVO) derived gas oils.

13. The use of an additive mixture in a fuel composition for reducing the cloud point (as measured according to DIN EN ISO 3015) and cold filter plugging point (as measured according to DIN EN 116) of the fuel composition, wherein the fuel composition comprises a base fuel and an additive mixture, wherein the base fuel comprises a renewable fuel component, and wherein the additive mixture comprises (i) a first additive comprising a long-chain carboxylic acid polyamine and (ii) a second additive comprising an ionic or nonionic oil-soluble polar organic nitrogen-containing compound having a single nitrogen atom per molecule. The weight ratio of the first additive to the second additive is in the range of 6:1 to 2:

1.

14. A method for reducing the cloud point (as measured according to DIN EN ISO 3015) and cold filter plugging point (as measured according to DIN EN 116) of a fuel composition, wherein the method comprises adding an additive mixture to the fuel composition, wherein the fuel composition comprises a base fuel, wherein the base fuel comprises a renewable fuel component, wherein the additive mixture comprises (i) a first additive comprising a long-chain carboxylic acid polyamine and (ii) a second additive comprising an ionic or nonionic oil-soluble polar organic nitrogen-containing compound having a single nitrogen atom per molecule. The weight ratio of the first additive to the second additive is in the range of 6:1 to 2:1.

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