Use of cleaning additives

Abstract

Use of a detergent additive in a fuel composition to reduce microbial growth. The present invention relates to a wide range of fuel compositions, including diesel fuels, heating fuels, aviation fuels, marine fuels, and the like.

Description

[Technical Field]

[0001] This invention relates to the use of a cleaning additive in a fuel composition to reduce microbial culture. [Background technology]

[0002] Fuel tanks and distribution systems provide an environment in which microorganisms can proliferate. Three main types of microorganisms that utilize putrefactive and corrosive hydrocarbons in fuel systems exist: bacteria, yeasts, and molds, the latter two often referred to as fungi. Microorganisms are ubiquitous, capable of infecting fuel at any point in the distribution network, surviving and growing in the water / aqueous phase associated with the fuel, and extracting their nutrients across the fuel / water interface (most nutrients diffuse into the cells in aqueous solutions). Microorganisms require substantial amounts of elements such as carbon, hydrogen, sulfur, nitrogen, and phosphorus, trace amounts of other elements, and some form of oxygen. The rate and type of microbial growth depend on factors such as aqueous phase pH, oxygen availability, ambient temperature, and nutrient availability. Optimal cultivation is achieved in a temperature range of 15°C to 40°C and a neutral / slightly acidic pH. Most of these conditions are met in fuel tanks and distribution systems, thereby providing an ideal environment for microbial cultivation. Water, as one major factor, exacerbates the situation and cannot be completely eradicated due to condensation effects, leaks in tank roofs, inadequate housekeeping, etc. Therefore, fuel storage systems are never sterile; at best, the goal is to limit microbial culture to an acceptable level through the adoption of good housekeeping practices.

[0003] There are several undesirable consequences of microbial cultivation in fuel systems. One such consequence is microbially induced corrosion (MIC), which is corrosion caused or accelerated by microorganisms.

[0004] Microbial cells can exist in either a planktonic (single-celled) or sessile (attached to a surface) form. Biofilms form when a collection of microorganisms (primarily bacteria) irreversibly adheres to a surface and begins to excrete a mucous extracellular biopolymer. Biofilms enhance microbial interactions, providing greater access to nutrients, environmental stability, and protection from viruses and biocides. These microbial communities can adhere to the sidewalls and bottoms of fuel storage tanks, potentially causing microbial-induced corrosion (MIC).

[0005] MIC is one of the most serious consequences of microbial culture. Aerobic bacteria produce organic acids, depleting the oxygen supply and creating an oxygen-deficient zone around it. This creates an oxygen gradient that leads to the formation of anodized corrosion pits. Sulfate-reducing bacteria (SRBs) can increase this corrosion by producing H2S, HS, and S2, all of which are highly aggressive against steel.

[0006] Other consequences of microbial culture in fuel systems include blockage of filters, valves, and pipelines, increased pump wear, and the production of biosurfactants that can cause stable water turbidity and coalescer inactivation. In particular, fungi are involved in filter blockage in vehicle fuel systems. Fuel filter clogging is often caused by mold growth, which manifests as a mat of hyphae (long fungal filaments) at the fuel / water interface. Loss of product quality, foul odor, cloudiness and discoloration, and injector contamination can also be undesirable consequences of microbial culture.

[0007] Biofuels (e.g., FAME) can play a role in replacing fossil fuels to meet greenhouse gas emission reduction targets. Globally, many countries have established or are developing biofuel directives, and some countries (e.g., Indonesia) have introduced B30 (30% biofuel), which is far above the current EU directive level of B7 (7% biofuel). However, it is well established that biodiesel and its blends are more susceptible to microbial cultivation than conventional hydrocarbon diesel, particularly at the EU directive level. The reason cited for this is that FAME is easily digestible by microorganisms, is more hygroscopic than conventional diesel, and results in the entrainment of more free water.

[0008] Gas-to-liquid (GTL) technology currently converts CH4 / methane from natural gas—the cleanest-burning fossil fuel—into high-quality liquid fuel products otherwise produced from crude oil. GTL fuels can help reduce localized emissions in conventional diesel vehicles. GTL fuels also have other applications, such as synthetic marine fuels in inland waterway vessels in contrast to conventional marine diesel engines. Although GTL fuels are more biodegradable than conventional diesel due to their negligible aromatic content and simple structure (fully saturated), they are known to be more susceptible to microbial culture than conventional diesel. Fuel handling and storage conditions regarding microbial culture can be considered even more stringent for inland waterway vessels than for road applications, due to the possibility of water being present in tanks during refueling and on bunker vessels.

[0009] In the past, attempts have been made to resolve cases of microbial spoilage in fuels and fuel systems. Currently, chemical treatments such as biocides and biostats, along with physical control methods such as good housekeeping, sedimentation, filtration, centrifugation, and heat treatment, are used to control and eliminate microbial growth in fuel systems.

[0010] Unfortunately, chemical treatments are toxic due to their properties, and their handling presents serious health, safety, and environmental problems. Commonly used isothiazolinone chemicals, for example, are skin sensitizers. Furthermore, waste biomass must be disposed of after chemical treatment, which can be time-consuming and costly. [Overview of the project]

[0011] Therefore, it is desirable to provide an alternative method for reducing microbial growth in fuel and fuel systems.

[0012] The present invention provides for the use of a cleaning additive in a fuel composition to reduce microbial culture.

[0013] According to another aspect of the present invention, a method for reducing microbial culture in a fuel composition is provided, comprising the step of introducing a cleaning additive into the fuel composition.

[0014] The use of the cleaning additives described herein has been found to reduce microbial growth in fuel compositions to which the cleaning additives are added. Therefore, the present invention can lead to a reduction in cases of microbial spoilage in a wide range of fuel compositions. [Brief explanation of the drawing]

[0015] [Figure 1] This is a graph displaying the experimental data generated in Example 1. [Figure 2] Table 5 below shows a graphical representation of the experimental data, particularly the average dry biomass weight (g) after 4 weeks and 12 weeks for the fuels tested in Example 2 below, with and without additives. [Figure 3] Table 5 below shows a graphical representation of the experimental data, specifically the average dry biomass weight (g) for all fuel formulations tested in Example 2 below, with and without performance additive package 2, performance additive package 3, cleaning additive 1, and cleaning additive 2. [Modes for carrying out the invention]

[0016] As used herein, the use of a cleaning additive in a fuel composition to reduce microbial growth in the fuel composition is provided.

[0017] In the context of this embodiment of the present invention, the term “reduce microbial culture” encompasses any degree of reduction in microbial culture. Microbial culture can be measured by any preferred method, such as the biomass method described in the following examples. The reduction in microbial culture may be 10% or more, preferably 20% or more, more preferably 50% or more, and especially 70% or more, compared to microbial culture in a similar fuel composition without cleaning additives, particularly during the period the fuel composition is stored in a fuel tank, for example, for a period of up to 12 weeks. As used herein, the term “reduce microbial culture” also, firstly, encompasses the prevention of microbial growth.

[0018] The present invention relates to a wide range of fuel applications, including diesel fuel, heating fuel, aviation fuel, marine fuel, and mixtures thereof. Preferred fuel applications include diesel fuel and aviation fuel.

[0019] The first essential component of this specification is a cleaning additive, which means an agent (preferably a surfactant) that can act to remove and / or prevent the accumulation of combustion-related deposits in the engine, particularly in fuel injection systems such as injector nozzles. Such materials may also be referred to as dispersant additives.

[0020] Detergent-containing diesel fuel additives are known and commercially available. Examples of suitable detergent additives include, but are not necessarily limited to, polyolefin-substituted succinimides or succinimides of polyamines, aliphatic amines, Mannich bases or amines, polyolefin maleic anhydrides, and quaternary ammonium salts, and mixtures thereof. Preferred detergent additives for use herein are nitrogen-containing detergents. In one embodiment, the detergent additive for use herein is a polyolefin-substituted succinimide such as polyisobutylene succinimide. In another embodiment, the detergent additive for use herein is a quaternary ammonium salt.

[0021] Many of the above detergents are nitrogen-containing detergents. Since nitrogen is an essential nutrient for microorganisms, it is particularly surprising that it has been found that the above-mentioned nitrogen-containing detergents reduce microbial growth when contained in the fuel composition.

[0022] Fuel additives can promote the entrainment of water in the fuel due to their surfactant properties, especially at particularly high treatment rates, and also act as a food source, and additives containing the essential nutrient nitrogen are particularly important. Therefore, it would be reasonable to assume that fuels blended with performance additives, especially nitrogen-containing performance additives such as nitrogen-containing detergents, would be more conducive to microbial attack. Surprisingly, the inventors have found that detergent additives such as nitrogen-containing detergents surprisingly inhibit microbial growth in the fuel composition. In particular, detergent additives such as nitrogen-containing detergents have been found to surprisingly inhibit microbial growth in the fuel composition, and the microorganisms have been found to be fungal species. This is particularly advantageous since filamentous fungi are involved in filter plugging problems.

[0023] The detergent additive is preferably present in the fuel composition at a level of active substance detergent in the range of 5 ppmw to 10,000 ppmw, preferably 5 ppmw to 1000 ppmw, more preferably in the range of 5 to 500 ppmw, even more preferably in the range of 10 to 200 ppmw, based on the entire fuel composition.

[0024] In one embodiment of the present invention, the cleaning additive is a component of the cleaning additive package, together with one or more other additive components. Examples of other suitable additive components are provided in more detail below.

[0025] The diesel fuel compositions described herein may include a diesel base fuel in addition to a detergent additive.

[0026] The diesel-based fuel may be any petroleum-derived diesel suitable for use in internal combustion engines, such as petroleum-derived low-sulfur diesel containing less than 50 ppm of sulfur, for example, ultra-low sulfur diesel (ULSD) or zero-sulfur diesel (ZSD). Preferably, the low-sulfur diesel contains less than 10 ppm of sulfur.

[0027] The petroleum-derived low-sulfur diesel preferred for use in this invention conforms to the EN590 standard. It typically has a sulfur content of 0.81-0.865 g / cm³ at 15°C, preferably 0.82-0.85 g / cm³, more preferably 0.825-0.845 g / cm³. 3 Density, cetane number of at least 51 (ASTM D613), and at 40°C, 1.5 to 4.5, preferably 2.0 to 4.0, more preferably 2.2 to 3.7 mm 2 It has a kinematic viscosity of 1 / second (ASTM D445).

[0028] In one embodiment, the diesel-based fuel is conventional petroleum-derived diesel.

[0029] A more preferred component of the fuel composition described herein is biodiesel fuel. Biodiesel fuel is a fuel derived from biological materials.

[0030] The biodiesel components are preferably present in the fuel composition of this specification at levels of 5% v / v or more and up to 50% v / v, preferably 5% v / v to 30% v / v, for example, 7% v / v, 10% v / v, 20% v / v, and 30% v / v.

[0031] In one embodiment of the present invention, the fuel composition herein does not contain biodiesel components (i.e., so-called "B0" fuel).

[0032] Preferred biodiesel components for use herein are fatty acid alkyl esters (FAAEs). It is known that diesel fuel compositions may contain fatty acid alkyl esters (FAAEs), particularly fatty acid methyl esters (FAAEs). Examples of preferred FAAEs include rapeseed methyl ester (RME), palm oil methyl ester (POME), and soy methyl ester (SME). FAAEs are typically derived from biological sources and are typically included to reduce the environmental impact of fuel production and consumption processes, or to improve lubricity.

[0033] FAAEs, of which methyl esters are the most commonly used in the context of diesel fuel, are already known as renewable diesel fuels (so-called "biodiesel" fuels). They contain long-chain carboxylic acid molecules (generally 10 to 22 carbon atoms long), each with an alcohol molecule attached to one end. Organically derived oils such as vegetable oils (including recycled vegetable oils) and animal fats (including fish oils) can be subjected to a transesterification process with alcohols (typically C1-C5 alcohols) to form corresponding fatty esters, typically monoalkylated. This process is preferably catalyzed with either an acid or a base (e.g., the base KOH) to convert the triglycerides contained in the oil from their glycerol backbone to the fatty acid components of the oil. FAAEs can also be prepared from used cooking oils and can be prepared by standard esterification from fatty acids.

[0034] In the present invention, FAAE may be any alkylated fatty acid or a mixture of fatty acids. The fatty acid components are preferably derived from a biological source, more preferably from a plant source. They may be saturated or unsaturated, and in the latter case, they may have one or more, preferably up to six, double bonds. They may be linear or branched, cyclic or polycyclic. Preferably, they have 6 to 30, preferably 10 to 30, more preferably 10 to 22, 12 to 24, or 16 to 18 carbon atoms, including the acid group -CO2H. FAAE typically comprises a mixture of different fatty acid esters of different chain lengths, depending on its source.

[0035] Preferred FAAEs for use in the present invention are selected from natural fatty oils, such as tall oil, rapeseed oil, coconut oil, or soybean oil.

[0036] FAAE is preferably a C1-C5 alkyl ester, more preferably a methyl, ethyl, propyl, (preferably isopropyl) or butyl ester, even more preferably a methyl or ethyl ester, particularly a methyl ester. In one embodiment herein, FAAE is selected from methyl esters of coconut oil (POME) and methyl esters of rapeseed oil (RME), and mixtures thereof.

[0037] Generally, it may be natural or synthetic, refined or unrefined ("crude").

[0038] FAAE may contain impurities or by-products as a result of the manufacturing process.

[0039] The FAAE preferably conforms to the specifications applicable to the rest of the fuel composition and / or the base fuel to which it is added, taking into account the intended use of the composition (e.g., in which geographical region and at what time). In particular, the FAAE preferably has a flash point higher than 101°C (IP 34) and a fossil content of 1.9-6.0 mm. 2 / second, preferably 3.5-5.0mm 2Kinematic viscosity at 40°C (IP 71) per second, 845-910 kg / m³ at 15°C. 3 Preferably 860-900 kg / m 3 It has a density (IP 365, EN ISO 12185 or EN ISO 3675), a water content of less than 500 ppm (IP 386), a T95 of less than 360°C (measured according to IP 123, the temperature at which 95% of the fuel has evaporated), an acid value of less than 0.8 mg KOG / g, preferably less than 0.5 mg KOH / g (IP 139), and an iodine (I2) value of less than 125 grams, preferably less than 120 grams or less than 115 grams per 110 g of fuel (IP 84). It also preferably contains less than 0.2% w / w of free methanol, less than 0.02% w / w of free glycerol, and more than 96.5% w / w of ester (by gas chromatography (GC), for example). In general, it may be preferable that the FAAE conforms to the European standard EN14214 for fatty methyl esters for use as diesel fuel.

[0040] Two or more FAAEs may be added to the diesel fuel composition according to the present invention, either separately or as a pre-prepared blend.

[0041] FAAEs can be incorporated into a fuel composition, typically as a blend (i.e., a physical mixture), optionally together with one or more other fuel components (such as diesel-based fuels), and optionally together with one or more fuel additives. It is preferable that the FAAEs be incorporated into the fuel composition before the composition is introduced into the engine that will run on the fuel composition.

[0042] The fuel compositions herein may include paraffinic diesel fuel in addition to or instead of the diesel-based fuel described above. Suitable paraffinic diesel fuel for use in the present invention can be derived from any suitable source, insofar as it is suitable for use in fuel compositions, particularly diesel fuel compositions.

[0043] Suitable paraffinic diesel fuels include, for example, diesel fuel derived from Fischer-Tropsch, diesel fuel derived from hydrogenated vegetable oil (HVO), and mixtures thereof.

[0044] The paraffinic diesel fuel preferred for use in this specification is Fischer-Tropsch diesel fuel. The paraffinic nature of Fischer-Tropsch diesel fuel means that diesel fuel compositions containing it have a higher cetane number compared to conventional diesel.

[0045] Fischer-Tropsch derived diesel is a preferred paraffinic diesel for use herein, but the term “paraffinic diesel” as used herein also includes paraffinic diesel derived from the hydrogenation (HVO) of vegetable oils. The HVO process is based on oil refining technology, which uses hydrogen to remove oxygen from triglyceride vegetable oil molecules, splitting the triglycerides into three separate chains to produce paraffinic hydrocarbons.

[0046] If present, paraffinic diesel fuel (i.e., Fischer-Tropsch derived diesel fuel, hydrogenated vegetable oil derived diesel fuel) preferably consists of at least 95% w / w, more preferably at least 98% w / w, even more preferably at least 99.5% w / w, and most preferably up to 100% w / w of paraffinic components, preferably iso and normal paraffins, and preferably contains 80% w / w or more isoparaffins.

[0047] "Fischer-Tropsch derived" means that the fuel or base oil is a synthetic product of the Fischer-Tropsch condensation process, or is derived therefrom. The term "non-Fischer-Tropsch derived" may be interpreted accordingly. Fischer-Tropsch derived fuels are sometimes referred to as GTL (gas-to-liquid) fuels.

[0048] The Fischer-Tropsch reaction converts carbon monoxide and hydrogen into longer-chain, usually paraffinic, hydrocarbons, i.e., In the presence of a suitable catalyst, typically at high temperatures (e.g., 125-300°C, preferably 175-250°C) and / or high pressures (e.g., 5-100 bar, preferably 12-50 bar), n(CO+2H2)=(-CH2-) n Add +nH2O+ and heat. If desired, a hydrogen:carbon monoxide ratio other than 2:1 may be used.

[0049] Carbon monoxide and hydrogen themselves can be derived from organic or inorganic sources, natural or synthetic sources, typically natural gas or organically derived methane. More recently, technologies for obtaining carbon monoxide and hydrogen from other sources, including more sustainable sources, have been investigated and used. For example, starting with carbon dioxide and water, free hydrogen can be obtained by electrolyzing the water, typically using electricity from a sustainable source. This hydrogen can then react with carbon dioxide in a “reverse water shift reaction” to obtain a carbon monoxide source. This carbon monoxide can then be reacted with the remaining hydrogen in a typical Fischer-Tropsch synthesis process. Due to the use of electrolysis, some of these production processes are referred to as “power-to-liquids.”

[0050] Diesel fuel, kerosene fuel, and base oil products can be obtained directly from the Fischer-Tropsch reaction, or indirectly from hydrogenated Fischer-Tropsch products, for example, by fractionation of Fischer-Tropsch synthetic products. Hydrogenation may involve hydrocracking (see, for example, British Patent No. 2077289 and European Patent No. 0147873) to adjust the boiling point range and / or hydroisomerization which can improve low-temperature fluidity by increasing the proportion of branched paraffins. European Patent No. 0583836 describes a two-step hydrogenation process in which the Fischer-Tropsch synthetic product is first subjected to hydroconversion under conditions that are substantially free from isomerization or hydrocracking (which hydrogenates olefins and oxygen-containing components), and then at least a portion of the resulting product is subjected to hydroconversion under conditions that undergo hydrocracking and isomerization to obtain a substantially paraffinic hydrocarbon fuel or oil. The desired diesel fuel fraction may then be isolated, for example, by distillation.

[0051] Other post-synthesis treatments, such as polymerization, alkylation, distillation, decomposition-decarboxylation, isomerization, and hydrogenation, may be used to modify the properties of the Fischer-Tropsch condensation product, for example, as described in U.S. Patent Nos. A-4125566 and A-4478955.

[0052] Typical catalysts for the Fischer-Tropsch synthesis of paraffinic hydrocarbons contain, as catalytically active components, metals from Group VIII of the periodic table, particularly ruthenium, iron, cobalt, or nickel. Suitable such catalysts are described, for example, in European Patent No. 0583836.

[0053] An example of a Fischer-Tropsch-based process is SMDS (Shell Middle Distillate Synthesis), described in van der Burgt et al.'s "The Shell Middle Distillate Synthesis Process" (see above). This process (sometimes also referred to as Shell "Gas-to-Liquids" or "GTL" technology) produces diesel-range products by converting synthesis gas (primarily methane) from natural gas into heavy long-chain hydrocarbon (paraffin) waxes, which are then hydroconverted and fractionated to produce liquid transport fuels such as diesel and kerosene. Versions of the SMDS process that utilize fixed-bed reactors for the catalytic conversion step are currently used at Pearl GTL in Bintulu, Malaysia, and Ras Laffan, Qatar. Kerosene and (gas) oil prepared by the SMDS process are commercially available, for example, from Royal Dutch / Shell Group of Companies.

[0054] The Fischer-Tropsch process results in diesel fuel derived from Fischer-Tropsch that is essentially free of sulfur and nitrogen, or contains undetectable levels of them. Compounds containing these heteroatoms tend to act as poisons to the Fischer-Tropsch catalyst and are therefore removed from the synthesis gas feed. Furthermore, the process, as it is normally operated, produces no aromatic components, or substantially none.

[0055] For example, the aromatic content of Fischer-Tropsch diesel fuel, as measured by ASTM D4629, is typically less than 1% w / w, preferably less than 0.5% w / w, and more preferably less than 0.1% w / w.

[0056] Generally speaking, Fischer-Tropsch-derived fuels have a relatively low level of polar components, especially polar surfactants, compared to, for example, petroleum-derived fuels. This is thought to contribute to the improvement of defoaming and cloud removal performance. Such polar components can include, for example, oxygenated additives, as well as sulfur and nitrogen-containing compounds. The low level of sulfur in Fischer-Tropsch-derived fuels generally indicates that both oxygenated additives and nitrogen-containing compounds are at low levels, because all are removed by the same treatment process.

[0057] The preferred Fischer-Tropsch-derived middle distillate fuel for use herein is a liquid hydrocarbon middle distillate fuel having a distillation range similar to that of petroleum-derived diesel, typically within the range of 160 °C to 400 °C and preferably having a T95 of 360 °C or less. Also, Fischer-Tropsch-derived fuels tend to have fewer undesirable fuel components such as sulfur, nitrogen, and aromatics.

[0058] The preferred Fischer-Tropsch-derived middle distillate for use herein meets the EN15940 standard.

[0059] The preferred Fischer-Tropsch-derived middle distillate fuel typically has a density (measured by EN ISO 12185) of 0.76 to 0.80, preferably 0.77 to 0.79, more preferably 0.775 to 0.785 g / cm 3 at 15 °C.

[0060] The preferred Fischer-Tropsch-derived middle distillate fuel for use herein has a cetane number (ASTM D613) greater than 70, suitably 70 to 85, most suitably 70 to 77.

[0061] The preferred Fischer-Tropsch-derived middle distillate fuel for use herein has a kinematic viscosity (at 40 °C) of 2.0 mm 2 / s to 5.0 mm 2 / s, preferably from 2.5 mm 2 / s to 4.0 mm 2It has a kinematic viscosity at 40°C in the range of / second (measured according to ASTM D445).

[0062] The Fischer-Tropsch diesel fuel preferred for use herein has a sulfur content of 5 ppmw (parts per million by weight) or less, preferably 2 ppmw or less (ASTM D2622).

[0063] The Fischer-Tropsch-derived diesel fuel preferred for use in the present invention is manufactured as a separate end product suitable for sale and for use in applications requiring specific characteristics of diesel fuel. In particular, it exhibits a distillation range that falls within the range typically associated with Fischer-Tropsch-derived diesel fuel, as described above.

[0064] The fuel composition used in the present invention may include a mixture of two or more paraffinic diesel fuels, such as two or more Fischer-Tropsch diesel fuels.

[0065] If present, the Fischer-Tropsch derived component used herein (i.e., Fischer-Tropsch derived diesel fuel) preferably contains 3% w / w or less, more preferably 2% w / w or less, and even more preferably 1% w / w or less, of the weight of the Fischer-Tropsch derived component, cycloparaffin (naphthene).

[0066] If present, the Fischer-Tropsch derived component used herein (i.e., Fischer-Tropsch derived diesel fuel) preferably contains olefins at a rate of 1% w / w or less, more preferably 0.5% w / w or less, by weight of the Fischer-Tropsch derived component.

[0067] The diesel fuel compositions described herein for use in the present invention are particularly suitable for use as diesel fuel, in which case the fuel composition is a diesel fuel composition that can be used for Arctic applications as a winter-grade diesel fuel due to its excellent low-temperature fluidity characteristics.

[0068] For example, a cloud point of -10°C or lower (EN 23015) or a cold filter plugging point (CFPP) of -20°C or lower (measured by EN 116) may be possible with the fuel compositions of this specification.

[0069] Generally speaking, in the context of the present invention, the fuel composition may contain fuel additives in addition to the cleaning additives already described.

[0070] Unless otherwise specified, the concentration of each such additive (active substance) in the fuel composition is preferably in the range of 1 to 400 ppmw, preferably up to 10,000 ppmw, more preferably 1 to 1,000 ppmw, and advantageously 1 to 200 ppmw. Such additives may be added at various stages during the production of the fuel composition. Those added to the base fuel at the refinery may be selected from, for example, antistatic agents, pipeline resistance reducers, middle distillate flow improvers (MDFIs) (e.g., ethylene / vinyl acetate copolymer or acrylate / maleic anhydride copolymer), lubricity improvers, antioxidants, and wax settling inhibitors.

[0071] Other components that may be incorporated as fuel additives in combination with the cleaning additive include, for example, lubricity enhancers, such as dehazing agents such as alkoxylated phenol-formaldehyde polymers, defoaming agents (e.g., commercially available polyether-modified polysiloxanes), ignition enhancers (cetane enhancers) (e.g., 2-ethylhexyl nitrate (EHN), cyclohexyl nitrate, di-tert-butyl peroxide, and those disclosed in column 2, line 27 to column 3, line 21 of U.S. Patent No. 4,208,190), rust inhibitors (e.g., propane-1,2-diol hester of tetrapropenylsuccinate, or succinylsuccinate). Examples include polyhydric alcohol esters of succinic acid derivatives, wherein the succinic acid derivative has an unsubstituted or substituted aliphatic hydrocarbon group containing 20 to 500 carbon atoms in at least one of its α-carbon atoms (e.g., pentaerythritol diester of polyisobutylene-substituted succinic acid), corrosion inhibitors, fragrances, wear-resistant additives, antioxidants (e.g., phenols such as 2,6-di-tert-butylphenol, or phenylenediamines such as N,N'-di-sec-butyl-p-phenylenediamine), metal deactivators, antistatic additives, and mixtures thereof.

[0072] In a preferred embodiment of the present invention, other additive components in the cleaning additive package are selected from corrosion inhibitors, metal passivators, antioxidants, metal deactivators, fragrances, and mixtures thereof.

[0073] The present invention may be particularly applicable when the fuel composition is used or intended to be used in direct injection diesel engines, such as rotary pump, inline pump, unit pump, electronic unit injector or common rail type direct injection diesel engines, or indirect injection diesel engines or HCCI engines. The fuel composition may be suitable for use in high-horsepower and / or low-horsepower diesel engines, as well as in engines designed for on-road or off-road use.

[0074] In order to be suitable for at least the applications listed above, the final fuel composition is preferably a diesel fuel composition that meets the EN590 standard (October 2017).

[0075] When a GTL-based fuel is included in the fuel composition of this specification, it is preferable that the final fuel composition fuel meets the EN15940 standard (2019).

[0076] The present invention may also be applicable when the fuel composition is used or intended to be used in stationary applications such as heating oil systems, heating oil burners, and / or stationary generators.

[0077] A heating oil composition suitable for use in this specification has properties according to standard DIN 51603 (2020).

[0078] The present invention will be described with reference to the following non-limiting embodiments. [Examples]

[0079] Example 1 In Example 1, four fuel samples were used, as shown in Table 1 below.

[0080] [Table 1]

[0081] [Table 2]

[0082] Test Procedure Test microorganisms A specified inoculum with known hydrocarbon decomposition capabilities, such as contaminated field diesel samples, was used. 1 ml was taken from the contaminated field diesel sample and used to inoculate a 70:30 ml aqueous medium / fuel mixture. This was done for each of the fuels listed in Table 1 above, and the mixtures were incubated for 8 days to form cultures or microbial communities. Incubation was carried out in the dark at 25°C. Then, 100 μl of the aqueous phase from each microbial community was used to inoculate Microcosmus.

[0083] Microcosm Setup Stainless steel coupons (to promote biofilm growth) were inserted into vials. 5 ml of Bushnell Haas nutrient medium (aqueous phase) was decanted and covered with 5 ml of fuel. The microbial community was then inoculated with either GTL fuel or B7 culture. Thus, two inoculum were derived from a single field sample.

[0084] Test protocol Microbial culture and diversity were evaluated over a month by dry biomass weight to determine the culture volume. This is a simple technique designed to provide a direct measurement of the total microbial load at the end of the experiment. The culture visible at the interface was captured, solvent washed to remove fuel residue, dried in an oven, cooled, and weighed. The results of Example 1 are shown in Figure 1. In Figure 1, the key characteristics of the fuel sample are as follows: GA1=GTL fuel (added) (crowd 1) GU1 = GTL fuel (no additives) (Group 1) DA1=B7 fuel (added) (crowd 1) DU1 = B7 fuel (no additives) (Group 1) GA2=GTL fuel (added) (crowd 2) GU2 = GTL fuel (no additives) (Group 2) DA2=B7 fuel (added) (crowd 2) DU2=B7 fuel (no additives) (Group 2)

[0085] As can be seen from Figure 1, compared to the control fuel without the performance additive package, the fuel containing performance additive package 1 (containing PIBSI cleaning additive) showed a decrease in biomass growth. This is particularly surprising for nitrogen-containing cleaning agents, considering that nitrogen is a nutrient for microorganisms.

[0086] Example 2 Table 5 below shows the fuels used in Example 2. Each fuel contained either an EN590 base fuel or a GTL EN15940 base fuel, with or without FAME, and with or without performance additive packages / cleaning additives, as indicated. The physicochemical properties of the EN590 base fuels used in this example are shown in Table 3 below. The physicochemical properties of the GTL fuels used in this example are shown in Table 4 below. The FAME in the B7 fuel (containing 7% biofuel) was derived from SME / RME. The FAME used in the B30 fuels (each containing 30% biofuel) was derived from SME / RME and POME. The FAME used in the B50 fuel (containing 50% biofuel) was derived from POME.

[0087] The additives used were as follows: Performance Additive Package 2: Contains a cleaning additive. None of the other components in Performance Additive Package 2 have biocidal effects. Performance Additive Package 2 is used in all fuel formulations except EN 590 B0.

[0088] Performance Additive Package 3: Contains a cleaning additive. None of the other components present in Performance Additive Package 3 have biocidal effects. Performance Additive Package 3 is used in GTL and EN590 B0 fuel formulations. Performance Additive Package 3 is a special additive formulation typically formulated for heating fuel formulations that do not contain FAME. The fuel formulations tested herein also do not contain FAME.

[0089] Cleaning additive 1: PIBSI cleaning additive (for use in EN 590 B7 fuel formulations).

[0090] Cleaning additive 2: Quaternary ammonium-based cleaning additive (used in EN 590 B7 fuel formulations).

[0091] [Table 3]

[0092] [Table 4]

[0093] The test protocol was the same as in Example 1, and the observed microbial cultures were evaluated for all tested fuel types based on the total dry weight of the biomass over a period of 3 months (at two time points: 4 weeks and 12 weeks). Three replicating microcosms were established at each time point. One microbial community was used as the inoculum.

[0094] The results are shown in Table 5 below. Figure 2 is a graphical representation of the data shown in Table 5, and in particular shows the average dry biomass weight (g) after 4 weeks and 12 weeks for all fuels tested in Example 2, with and without additives.

[0095] Figure 3 is a graphical representation of the data shown in Table 5, specifically the average dry biomass weight (g) for all tested fuel formulations with and without performance additive package 2, performance additive package 3, cleaning additive 1, and cleaning additive 2. Therefore, in Figure 3, the block titled "Perf Additive Package 2" represents the average dry biomass weight (g) for all formulations shown in Table 5 that contain performance additive package 2; the block titled "Perf Additive Package 3" represents the average dry biomass weight (g) for all formulations shown in Table 5 that contain performance additive package 3; the block titled "None" represents the average dry biomass weight (g) for all formulations shown in Table 5 that do not contain performance additive package or cleaning additive; the block titled "Det Additive 1" represents the average dry biomass weight (g) for all formulations shown in Table 5 that contain cleaning additive 1; and the block titled "Det Additive 2" represents the average dry biomass weight (g) for all formulations shown in Table 5 that contain cleaning additive 2.

[0096] [Table 5-1]

[0097] [Table 5-2] The present invention includes the following embodiments. [1] Use of a cleaning additive in a fuel composition to reduce microbial culture. [2] The use according to [1], wherein the cleaning additive is selected from polyolefin-substituted succinimide or polyamine succinimide, aliphatic amine, Mannich base or amine, polyolefin maleic anhydride, quaternary ammonium salts, and mixtures thereof. [3] The use according to [1] or [2], wherein the cleaning additive is a polyolefin-substituted succinimide, preferably a polyisobutylene succinimide. [4] The use according to [1] or [2], wherein the cleaning additive is a quaternary ammonium salt. [5] The use according to any one of [1] to [4], wherein the cleaning additive is present in the fuel composition at a level of 5 ppmw to 10,000 ppmw. [6] The use according to any one of [1] to [5], wherein the cleaning additive is a nitrogen-containing cleaning agent. [7] The use described in any of [1] to [6], wherein the cleaning additive is a component of the performance additive package. [8] The use according to any one of [1] to [7], wherein the fuel composition is selected from diesel fuel compositions, heating oil compositions, aviation fuel compositions, and marine fuel compositions. [9] The use according to any one of [1] to [8], wherein the fuel composition is a diesel fuel composition.

[10] The use according to [9], wherein the diesel fuel composition comprises a petroleum-derived diesel base fuel.

[11] The use according to [9] or

[10] , wherein the diesel fuel composition comprises a paraffin-based fuel selected from hydrotreated vegetable oil, Fischer-Tropsch-derived base fuel, and mixtures thereof.

[12] The use according to any one of [9] to

[11] , wherein the diesel fuel composition comprises a biodiesel component, preferably a fatty acid alkyl ester.

[13] A method for reducing microbial culture in a fuel composition, comprising the step of introducing a cleaning additive into the fuel composition.

Claims

1. Use of a cleaning additive in a fuel composition to reduce microbial culture, wherein the cleaning additive is a polyolefin-substituted succinimide, the fuel composition is a diesel fuel composition, the diesel fuel composition comprises a paraffin-based fuel selected from hydrogenated vegetable oil, Fischer-Tropsch-derived base fuel, and mixtures thereof, and the diesel fuel composition further comprises a fatty acid alkyl ester as a biodiesel component.

2. The use according to claim 1, wherein the cleaning additive is polyisobutylene succinimide.

3. The use according to claim 1 or 2, wherein the cleaning additive is present in the fuel composition at a level of 5 ppmW to 10,000 ppmW.

4. The use according to any one of claims 1 to 3, wherein the cleaning additive is a component of the performance additive package.

5. The use according to any one of claims 1 to 4, wherein the diesel fuel composition comprises a petroleum-derived diesel base fuel.

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