Use of paraffinic gas oil

Abstract

To provide a fuel-based solution that reduces the amount of SCR reagent required and is applicable to all SCR systems, regardless of the equipment used by the manufacturer.SOLUTION: To provide the use of a paraffinic gasoil in a diesel fuel composition for reducing the amount of SCR reagent required by an SCR system attached to a compression ignition internal combustion engine. The paraffinic gasoil comprises more than 95 wt.% paraffins, based on the total weight of said paraffinic gasoil, wherein said paraffinic gasoil is a Fischer-Tropsch-derived gasoil, and wherein said Fischer-Tropsch-derived gasoil has a kinematic viscosity at 40 °C in the range of from 2.0 to 5. 0mm2 / s and a viscosity in the range of from 0.76 to 0. 80g / cm3.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to the use of paraffinic gas oils to provide certain benefits in selective catalytic reduction (SCR) systems fitted to compression ignition engines. In particular, the present invention relates to the use of paraffinic gas oils to reduce the amount of SCR reagents required in selective catalytic reduction systems fitted to compression ignition engines. [Background technology]

[0002] Selective catalytic reduction (SCR) is a NOx emission control technique applicable to a wide range of diesel engines, from small, medium, and heavy-duty diesel engine systems to two-stroke, slow-speed marine engines. Essentially, in an SCR system, an SCR reagent (e.g., urea) is injected into the engine exhaust gas stream. When mixed with the exhaust gas, the SCR reagent decomposes to produce ammonia. The ammonia and exhaust gas mixture enters the SCR catalyst, where the ammonia reduces the NOx to nitrogen.

[0003] SCR systems are renowned for their efficient NOx emission removal, but require an "on-board" supply of SCR reagents. This SCR reagent consumption varies depending on engine operating conditions, but for average operating conditions, it typically ranges from 3% to 8% of parallel fuel consumption. This can be a cost and / or health and safety burden for vehicle owners, especially fleet operators. AdBlue® can be corrosive to some metals, and if spilled on the skin, it should be washed off immediately, and wearing protective gloves during the filling procedure is recommended.

[0004] Therefore, it would be desirable to provide a fuel-based solution that reduces the amount of SCR reagent required and is applicable to all SCR systems, regardless of the equipment used by the manufacturer.

[0005] It would also be desirable to provide a fuel-based solution to reduce the number of SCR reagent vehicle fills per year, thus minimizing user exposure to corrosive liquids. Summary of the Invention

[0006] It has now surprisingly been found that by using a paraffinic gas oil in a diesel fuel composition, a surprising and heretofore unrecognized reduction in the amount of SCR reagent required to achieve the required reduction in NOx emissions by an SCR system can be obtained.

[0007] According to the present invention there is provided the use of a paraffinic gas oil in a diesel fuel composition to reduce the amount of SCR (Selective Catalytic Reduction) reagents required by an SCR system fitted to a compression ignition internal combustion engine.

[0008] According to another aspect of the present invention, there is provided a method for reducing the amount of selective catalytic reduction (SCR) reagents required by an SCR system fitted to a compression ignition internal combustion engine, the method comprising introducing into the engine a diesel fuel composition comprising a paraffinic gas oil.

[0009] According to another aspect of the present invention there is provided the use of a paraffinic gas oil in a diesel fuel composition to reduce the number of SCR reagent vehicle fills per year.

[0010] It has been found that the use of paraffinic gas oils in diesel fuel compositions can result in a reduction in the amount of SCR (selective catalytic reduction) reagents required by SCR systems fitted to compression ignition internal combustion engines. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a graphical representation of the results shown in Table 3 below. DETAILED DESCRIPTION OF THE INVENTION

[0012] As used herein, there is provided the use of a paraffinic gas oil in a diesel fuel composition for the purpose of reducing the amount of SCR (selective catalytic reduction) reagent required by an SCR system installed in a compression ignition engine. In the context of this embodiment of the present invention, the term "reducing the amount of SCR reagent required" encompasses any degree of reduction in the amount of SCR reagent required by the SCR system. The reduction in the amount of SCR reagent required can be about 5% or more, preferably about 10% or more, more preferably about 20% or more, and particularly about 40% or more, compared to the amount of SCR reagent required by a similar SCR system when a similar fuel formulation is used to fuel a compression ignition engine but does not contain paraffinic gas oil (e.g., when the similar fuel formulation contains or consists of EN590 refined diesel fuel instead of paraffinic gas oil).

[0013] As used herein, the term "SCR reagent" refers to a substance or solution of a substance stored on a vehicle and introduced (e.g., sprayed) into the exhaust gas stream for reaction with exhaust NOx on an SCR catalyst according to engine exhaust system demand. An SCR reagent for use herein is any reagent suitable for use in an SCR system that can react (i.e., reduce) NOx in the exhaust gas (NOx) through itself or its decomposition products to produce nitrogen. Essentially, an SCR reagent can be ammonia itself or any substance whose decomposition products include ammonia.

[0014] Preferably, the SCR reagent is selected from urea, ammonia, ammonium salts such as ammonium formate and ammonium carbamate, and mixtures thereof. The SCR reagent can be present in anhydrous form or as an aqueous solution. In a preferred embodiment, the SCR reagent is urea, preferably an aqueous solution of urea.

[0015] A commercially available SCR reagent for use herein is AdBlue®, as defined by specification ISO 22241, commercially available from fuel and other suppliers.

[0016] The first essential component of the diesel fuel compositions herein is a paraffinic gas oil. The paraffinic gas oil fuel is present in the diesel fuel compositions herein at a level in the range of 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 diesel fuel composition.

[0017] In another embodiment herein, the paraffinic gas oil fuel is present in the diesel fuel composition as a blend together with a diesel fuel such as EN590 refined diesel fuel. In this embodiment, the paraffinic gas oil fuel is present in the diesel fuel composition at a level in the range of from 10% v / v to 99% v / v, more preferably from 20% v / v to 70% v / v, even more preferably from 20% v / v to 50% v / v, especially from 20% v / v to 30% v / v, based on the total diesel fuel composition.

[0018] The paraffinic gas oil for use in the present invention is It may be obtained from any suitable source, provided that it is suitable for use.

[0019] Suitable paraffinic gas oils include, for example, Fischer-Tropsch derived gas oils and gas oils derived from hydrogenated vegetable oil (HVO), and mixtures thereof.

[0020] In view of reducing the amount of SCR (selective catalytic reduction) reagents required by the SCR system, while ensuring that other properties such as viscosity, density, and distillation characteristics fall within diesel specification requirements, the paraffinic gas oil used herein is preferably a Fischer-Tropsch derived gas oil fuel. The paraffinic character of Fischer-Tropsch derived gas oil means that diesel fuel compositions containing it will have a higher cetane number than conventional diesel.

[0021] While Fischer-Tropsch derived gas oils are the preferred paraffinic gas oils used herein, the term "paraffinic gas oils" as used herein also includes those paraffinic gas oils derived from hydrotreating vegetable oils (HVO). The HVO process is based on petroleum refining technology. In this process, hydrogen is used to remove oxygen from triglyceride vegetable oil molecules, splitting the triglycerides into three separate chains to produce paraffinic hydrocarbons.

[0022] According to the present invention, a paraffinic gas oil for use herein (i.e. a Fischer-Tropsch derived gas oil, a gas oil derived from hydrogenated vegetable oil, etc.) will preferably consist 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 isoparaffins and normal paraffins.

[0023] "Fischer-Tropsch derived" means that the fuel or base oil is, or is derived from, the synthetic product of a Fischer-Tropsch condensation process. The term "non-Fischer-Tropsch derived" may be interpreted accordingly. Fischer-Tropsch derived fuels may also be referred to as GTL (Gas to Liquids) fuels.

[0024] The Fischer-Tropsch reaction converts carbon monoxide and hydrogen into longer chain, usually paraffinic, hydrocarbons in the presence of a suitable catalyst, usually at high temperature (e.g., 125-300°C, preferably 175-250°C) and / or pressure (e.g., 5-100 bar, preferably 12-50 bar): n(CO+2H2)=(-CH2-) n + nH2O + heat. If desired, hydrogen:carbon monoxide ratios other than 2:1 can be used.

[0025] The carbon monoxide and hydrogen may themselves be derived from organic or inorganic, natural or synthetic sources, usually either from natural gas or from organically derived methane.

[0026] Recently, techniques for deriving carbon monoxide and hydrogen from other sources, including more sustainable ones, have been explored and used. For example, starting with carbon dioxide and water, the water can be electrolyzed to produce free hydrogen, typically using electricity from a sustainable source. This hydrogen can react with carbon dioxide in a "reverse aqueous shift reaction" to produce a source of carbon monoxide. Alternatively, instead of the "reverse aqueous shift reaction," electrolysis can be used for the electrochemical conversion of carbon dioxide to the required carbon monoxide. This carbon monoxide (from the source described) can then be reacted with the remaining hydrogen in a typical Fischer-Tropsch synthesis process. Due to the use of electrolysis, these production processes Part of the process is called "Power-to-Liquid."

[0027] Gas oil, kerosene fuel, and base oil products can be obtained directly from the Fischer-Tropsch reaction or indirectly, for example, by fractionation of the Fischer-Tropsch synthesis product or by hydrogenation of the Fischer-Tropsch synthesis product. Hydrotreating involves hydrocracking to adjust the boiling range (see, for example, GB 2077289 and EP 0147873) and / or hydroisomerization, which can improve cold flow properties by increasing the proportion of branched paraffins. EP 0583836 describes a two-stage hydrotreating process in which the Fischer-Tropsch synthesis product is first subjected to hydroconversion under conditions that do not substantially undergo isomerization or hydrocracking (which hydrogenates olefins and oxygen-containing components), and then at least a portion of the resulting product is hydroconverted under conditions that cause hydrocracking and isomerization to occur, producing a substantially paraffinic hydrocarbon fuel or oil. The desired diesel fuel fraction can then be isolated, for example, by distillation.

[0028] Other post-synthetic treatments, such as polymerization, alkylation, distillation, cracking-decarboxylation, isomerization and hydromodification, can be used to modify the properties of the Fischer-Tropsch condensation products, as described, for example, in US-A-4,125,566 and US-A-4,478,955.

[0029] Typical catalysts for the Fischer-Tropsch synthesis of paraffinic hydrocarbons contain, as the catalytically active component, a metal from group VIII of the periodic table, in particular ruthenium, iron, cobalt, or nickel. Suitable such catalysts are described, for example, in EP 0 583 836.

[0030] An example of a Fischer-Tropsch-based process is the "Shell Middle Distillates Synthesis Process," SMDS (Shell Middle Distillates Synthesis) described by van der Burgt et al. (see above). This process (also sometimes referred to as Shell "gas to liquids" or "GTL" technology) produces diesel-range products by converting synthesis gas derived from natural gas (primarily methane) into heavy, long-chain hydrocarbon (paraffin) waxes that can then be hydroconverted and fractionated to produce liquid transportation fuels such as gas oil and kerosene. A version of the SMDS process utilizing a fixed-bed reactor for the catalytic conversion step is currently used at the Pearl GTL in Bintulu, Malaysia, and Ras Laffan, Qatar. Kerosene and (gas) oil prepared by the SMDS process are commercially available, for example, from the Royal Dutch / Shell Group of Companies.

[0031] Thanks to the Fischer-Tropsch process, Fischer-Tropsch derived gas oil contains essentially no or undetectable levels of sulfur and nitrogen. Compounds containing these heteroatoms tend to act as poisons to the Fischer-Tropsch catalyst, so they are removed from the syngas feed. Furthermore, normally operated processes produce no or virtually no aromatic compounds.

[0032] For example, the aromatics content of a Fischer-Tropsch gas oil, as determined by, for example, ASTM D4629, is typically less than 1% w / w, preferably less than 0.5% w / w, more preferably less than 0.1% w / w.

[0033] Generally speaking, Fischer-Tropsch derived fuels have relatively low levels of polar components, particularly polar surfactants, compared to, for example, petroleum-derived fuels. This is believed to contribute to improved antifoam and dehazing performance. Such polar components may include, for example, oxygenated compounds, sulfur- and nitrogen-containing compounds. The low levels of sulfur in Fischer-Tropsch derived fuels are due to the fact that all are removed by the same treatment process. Generally, it is an indicator of low levels of both oxygenated and nitrogen-containing compounds.

[0034] The Fischer-Tropsch derived gas oil fuels used in the present invention are liquid hydrocarbon middle distillate fuels having a distillation range similar to that of petroleum derived diesel, i.e., preferably with a T95 of 360° C. or less, typically in the range of 160° C. to 400° C. Again, Fischer-Tropsch derived fuels tend to be lower in undesirable fuel components such as sulfur, nitrogen and aromatics.

[0035] The Fischer-Tropsch derived gas oil fuel used in the present invention typically has a viscosity of 0.76 to 0.80 g / cm at 15°C. 3 , preferably 0.77 to 0.79 g / cm 3 , more preferably 0.775 to 0.785 g / cm 3 The resulting product will have a density (measured according to EN ISO 12185) of 1.0001.

[0036] The Fischer-Tropsch derived gas oil fuel used in the present invention preferably has a cetane number (ASTM D613) of greater than 70, suitably a cetane number of 70-85, most suitably a cetane number of 70-77.

[0037] The Fischer-Tropsch derived gas oil fuel used in the present invention preferably has a viscosity of 2.0 mm 2 / sec~5.0mm 2 / sec, preferably 2.5mm 2 / sec~4.0mm 2The kinematic viscosity at 40°C (measured according to ASTM D445) is in the range of 1 / sec.

[0038] The Fischer-Tropsch derived gas oil used in the present invention has a sulfur content (ASTM D2622) of not more than 5 ppmw (parts per million by weight), preferably not more than 2 ppmw.

[0039] The Fischer-Tropsch derived gas oil fuel used in the present invention is one which is suitable for sale and which is produced as a separate end product for use in applications requiring the particular properties of a gas oil fuel, in particular it exhibits a distillation range which falls within the ranges normally associated with Fischer-Tropsch derived gas oil fuels as described above.

[0040] A fuel composition according to the present invention may comprise a mixture of two or more Fischer-Tropsch derived gas oil fuels.

[0041] According to the present invention, the Fischer-Tropsch derived component (i.e., a Fischer-Tropsch derived gas oil) as used herein will preferably contain no more than 3% w / w, more preferably no more than 2% w / w, and even more preferably no more than 1% w / w of cycloparaffins (naphthenes) by weight of the Fischer-Tropsch derived component.

[0042] As used herein, a Fischer-Tropsch derived component (i.e., a Fischer-Tropsch derived gas oil) preferably contains no more than 1% w / w, more preferably no more than 0.5% w / w, of olefins by weight of the Fischer-Tropsch derived component.

[0043] The diesel fuel compositions described herein are particularly suitable for use as diesel fuels, and can be used as winter grade diesel fuels for extreme cold applications due to their excellent cold flow properties.

[0044] For example, a cloud point of -10°C or less (EN23015) or a cold filter plugging point (CFPP) of -20°C or less (measured by EN116) may be possible with the fuel compositions herein.

[0045] The diesel fuel compositions described herein may contain diesel-based fuel in addition to paraffinic gas oil.

[0046] The diesel-based fuel can be any petroleum-derived diesel suitable for use in internal combustion engines, such as petroleum-derived low-sulfur diesel containing less than 50 ppm sulfur, e.g., ultra-low sulfur diesel (ULSD) or zero sulfur diesel (ZSD). Preferably, the low-sulfur diesel contains less than 10 ppm sulfur.

[0047] Petroleum-derived low sulfur diesel preferred for use in the present invention typically has a sulfur content of 0.81 to 0.865 g / cm at 15°C. 3 , preferably 0.82 to 0.85 g / cm 3 , more preferably 0.825 to 0.845 g / cm 3 density, a cetane number of at least 51 (ASTM D613), and 1.5 to 4.5 mm at 40°C 2 / sec, preferably 2.0 to 4.0 mm 2 / sec, more preferably 2.2 to 3.7 mm 2 / sec kinematic viscosity (ASTM D445).

[0048] In one embodiment, the diesel-based fuel is conventional petroleum-derived diesel.

[0049] Generally speaking, in the context of the present invention, fuel compositions may contain fuel additives. Unless otherwise specified, the (active substance) concentration of each such additive in the fuel composition is preferably up to 10,000 ppmw, more preferably 5 to 1,000 ppmw, advantageously 75 to 300 ppmw, for example 95 to 150 ppmw. Such additives may be added at various stages during the production of the fuel composition. Additions to the base fuel at the refinery may be selected, for example, from antistatic agents, pipeline drag reducers, middle distillate flow improvers (MDFIs) (e.g., ethylene / vinyl acetate copolymers or acrylates / maleic anhydride copolymers), lubricity improvers, antioxidants, and wax anti-settling agents.

[0050] The fuel composition may contain a detergent, which refers to an agent (preferably a surfactant) that can act to remove and / or prevent the accumulation of combustion-related deposits inside the engine, particularly in the fuel injection system, e.g., in the injector nozzle. Such materials are sometimes referred to as dispersant additives. When the fuel composition contains a detergent, the preferred concentration is 20 to 500 ppmw, more preferably 40 to 500 ppmw, and most preferably 40 to 300 ppmw, 100 to 300 ppmw, or 150 to 300 ppmw of active substance detergent based on the total fuel composition. Detergent-containing diesel fuel additives are known and commercially available. Examples of suitable detergent additives include polyolefin-substituted succinimides or succinamides of polyamines, such as polyisobutylene succinimides or polyisobutylene amine succinamides, aliphatic amines, Mannich bases or amines, and polyolefins (e.g., polyisobutylene) maleic anhydride. In particular, polyolefin-substituted succinimides such as polyisobutylene succinimide are preferred.

[0051] Other components that may be incorporated as fuel additives, for example in combination with detergents, include lubricity improvers, dehazing agents such as alkoxylated phenol formaldehyde polymers, antifoaming agents (e.g., commercially available polyether-modified polysiloxanes), ignition improvers (cetane number improvers) (e.g., 2-ethylhexyl nitrate (EHN), cyclohexyl nitrate, di-tert-butyl peroxide, and those disclosed in US Pat. No. 4,208,190, column 2, line 27 to column 3, line 21), rust inhibitors (e.g., tetrapro propane-1,2-diol semiester of phenylsuccinic acid, or polyhydric alcohol esters of succinic acid derivatives, succinic acid derivatives having an unsubstituted or substituted aliphatic hydrocarbon group containing 20 to 500 carbon atoms on at least one of their alpha carbon atoms, for example, pentaerythritol diester of polyisobutylene-substituted succinic acid), corrosion inhibitors, deodorants, anti-wear additives, antioxidants (for example, phenols such as 2,6-di-tert-butylphenol, or N,N'-di- phenylenediamines such as sec-butyl-p-phenylenediamine), metal deactivators, static dissipative additives and mixtures thereof.

[0052] The additive preferably contains an anti-foaming agent, more preferably in combination with a rust and / or corrosion inhibitor and / or lubricity additive.

[0053] In particular, it is particularly preferred for a lubricity improver to be included in the fuel composition if it has a low (e.g., 500 ppmw or less) sulphur content. The lubricity improver is conveniently present in a concentration of 50 to 1000 ppmw, preferably 100 to 1000 ppmw, based on the total fuel composition.

[0054] The (active matter) concentration of the dehazer in the fuel composition will preferably be in the range 1 to 20 ppmw, more preferably 1 to 15 ppmw, even more preferably 1 to 10 ppmw, and advantageously 1 to 5 ppmw. The (active matter) concentration of any ignition improver present will preferably be 600 ppmw or less, more preferably 500 ppmw or less, advantageously 300 to 500 ppmw.

[0055] The present invention may be particularly applicable where the fuel composition is used or intended to be used in a direct injection diesel engine, for example of the rotary pump, in-line pump, unit pump, electronic unit injector, or common rail type, or in a pre-chamber diesel engine. The fuel compositions herein may be suitable for use in large and / or small diesel engines, and in engines designed for on-road or off-road use.

[0056] To be suitable for at least the above uses, the diesel fuel compositions herein preferably have one or more of the following characteristics: 1.9mm at -40℃ 2 / sec or more, more preferably 1.9 to 4.5 mm 2 kinematic viscosity in the range of / sec, -800kg / m 3 More preferably, 800 to 860 kg / m 3 , and even more preferably 800 to 845 kg / m 3 Density in the range of T95 below -360℃, a cloud point in the range of -0°C to -13°C, more preferably -5°C to -8°C; CFPP in the range of -8°C to -30°C, more preferably -15°C to -20°C.

[0057] The invention is illustrated by the following non-limiting examples. [Example]

[0058] Example 1 Two different fuels were used in Example 1. Fuel 1 was a GTL gas oil containing 10 ppm of a hindered phenol antioxidant (2,6-di-tert-butyl-4-methylphenol, also known as BHT). Table 1 shows the physical and compositional characteristics of the GTL gas oil (Fuel 1) used in Example 1. The GTL gas oil (Fuel 1) was obtained from Pearl GTL, Ras Laffan, and is commercially available from Shell / Royal Dutch Group of Companies.

[0059] Fuel 2 was a conventional diesel fuel (Diesel B7). The physical characteristics of the conventional diesel fuel (Diesel B7) used in the example (Fuel 2) are shown in Table 2. As used herein, "Diesel B7" refers to a diesel-based fuel containing 7% biofuel content. [Table 1] [Table 2]

[0060] Test Method The vehicle used in Example 1 was a state-of-the-art (Euro VI) Mercedes Actros HGV truck fitted with an SCR system. Readily available AdBlue® (defined by specification ISO 22241) was used as the SCR reagent in the SCR system.

[0061] Before each test run, a forced regeneration of the DPF (diesel particulate filter) was performed to ensure the aftertreatment was in the same state at the start of each test. For each test run, the truck was driven around an oval test course for three hours at 89 kph.

[0062] During each test run, there was the ability to monitor and record various output parameters from the ECU (Engine Control Unit), which provided the instantaneous status of the engine, DPF, and SCR aftertreatment system. Such ECU parameters included SCR status, SCR reagent metered volume, SCR reagent tank level, NOx pre-catalyst, and NOx post-catalyst.

[0063] The average amounts of SCR reagent used in Example 1 versus fuel type are shown in Table 3 below. [Table 3]

[0064] The results in Table 3 show that the GTL fuel provides a benefit of 0.08 (8%) over the B7 diesel fuel. Figure 1 is a graph of the results shown in Table 3.

[0065] Example 2 Model calculations were prepared to illustrate the benefit of GTL fuel in reducing the number of SCR reagent charges per year.

[0066] Knowing various parameters of the vehicle makes it possible to calculate the number of SCR reagent fills per year, and thus reduce the number of fills when GTL fuel is used. For the purposes of these calculations, the SCR reagent is AdBlue®.

[0067] In the calculations below, the following abbreviations are used: AFC = Annual fuel consumption in litres ATV = AdBlue tank volume AdBlue consumption as a fraction of fuel consumption, taken as α=0.05 (i.e., 5%) β = AdBlue consumption benefit from GTL, expressed as a fraction AAF = AdBlue fill-up in 1 year Reduction in AdBlue filling at RAF=1 year The AAF and RAF can be expressed by the following formulas:

number

number

[0068] These equations are now applied to typical medium and long-haul vehicles to calculate the The expected benefits in reducing the number of AdBlue fills per year through use can be calculated.

[0069] In the calculations, the following was assumed: For these classes of vehicles, AdBlue consumption is typically 4% to 6% of fuel consumption, so a figure of 5% is used, i.e. α is considered to be 0.05. -144,000 miles is typical for the annual mileage per truck (long haul), resulting in an annual fuel consumption of 100716L and an annual AdBlue consumption of 5036L. -72,000 miles is typical for the annual mileage per truck (medium haul), resulting in an annual fuel consumption of 28968L and an annual AdBlue consumption of 1448L. -Fleet size was considered to be 30 vehicles. - the value of β (the AdBlue consumption benefit from GTL fuel, experimentally determined to be 0.08 (i.e., 8%) from Example 1). The various benefits of GTL use will vary depending on the sensitivity of the engine to the GTL chemistry. For example, regulated emissions (PM, NOx, HC, CO) measurements (published literature) show a wide range of benefits depending on numerous factors, including test conditions and engine type. It can reasonably be assumed that there will also be a large level of variation in the AdBlue requirement percentage benefit seen in different combined engine-SCR systems. Therefore, the value of β takes into account a reasonable level of variation. Thus, β ranges from 2% to 30%, with intermediate values ​​of 8% and 20%.

[0070] The results of these model calculations are shown in Table 4 below. [Table 4]

[0071] Example 3 In Example 3, two different fuels were used. Fuel 3 contained 10 ppm hindered fuel. The GTL gas oil (Fuel 3) used in Example 3 was a GTL gas oil containing a phenolic antioxidant (2,6-di-tert-butyl-4-methylphenol, also known as BHT). Table 5 shows the physical and compositional characteristics of the GTL gas oil (Fuel 3) used in Example 3. The GTL gas oil (Fuel 3) was obtained from Pearl GTL, Ras Laffan, and is commercially available from Shell / Royal Dutch Group of Companies.

[0072] Fuel 4 was a conventional diesel fuel (Diesel B7). The physical characteristics of the conventional diesel fuel (Diesel B7) used in the example (Fuel 4) are also shown in Table 5. As used herein, "Diesel B7" refers to a diesel-based fuel containing 7% biofuel content. [Table 5]

[0073] Test Method The purpose of Example 3 was to generate further experimental data to support the results obtained in Example 1, particularly by extending the testing to a larger number of vehicles, specifically a fleet of four.

[0074] Four vehicles were used in Example 3. These were state-of-the-art (three Euro VI-C, one Euro V1-D) Mercedes Actros HGV trucks fitted with SCR systems. AdBlue® (defined by specification ISO 22241), readily available on the European market, was used as the SCR reagent in each vehicle's SCR system.

[0075] Before each test run, a forced regeneration of the DPF (diesel particulate filter) was performed to ensure that the aftertreatment was in the same state at the start of each test. The test runs for the four trucks were of extended duration compared to the 3-hour test run in Example 1. For the test runs, each of the four trucks was driven around an oval test course at 70 kph with two driver shifts per day until the DPF (diesel particulate filter) soot load reached the DPF regeneration point. For some truck / fuel combinations, this represented over 40 hours of test runs at 70 kph. (Braking occurred approximately every 2-2.5 hours to accommodate driver rest or shift change periods, during which the engine remained idle. Overnight, the vehicles were stationary with the engines turned off for 8 hours.)

[0076] During each test run, there was the ability to monitor and record various output parameters from the ECU (Engine Control Unit), which provided the instantaneous status of the engine, DPF, and SCR aftertreatment system. Such ECU parameters included SCR status, SCR reagent metered volume, SCR reagent tank level, NOx pre-catalyst, and NOx post-catalyst.

[0077] The average amount of SCR reagent used in Example 3 versus fuel type for each of the four vehicles is shown in Table 6 below. [Table 6]

[0078] The results in Table 6 show that GTL fuel provides benefits ranging from 1.1% to 15.2% over B7 diesel fuel.

[0079] Consideration As can be seen from the results in Table 3, the graph in Figure 1, and Table 6, there is a significant reduction in the amount of SCR reagent required in the case of paraffinic GTL fuel compared to conventional diesel B7 fuel.

[0080] As shown in the model calculations in Table 4, there is a wide range of reductions in the number of AdBlue fills required per fleet per year when using paraffinic GTL fuel compared to B7 diesel fuel. The model values ​​cover the benefits for a variety of tank sizes and AdBlue consumption rates. The reduction in the number of SCR reagent vehicle fills per year provides the benefit of minimizing user exposure to corrosive liquids. [Mode of Invention] [1] Use of a paraffinic gas oil in a diesel fuel composition to reduce the amount of SCR reagent required by an SCR system installed in a compression ignition internal combustion engine. [2] 2. The use according to claim 1, wherein the SCR reagent is selected from urea, ammonia, and ammonium salts, and mixtures thereof. [3] 3. The use according to claim 1 or 2, wherein the SCR reagent is urea. [4] 4. Use according to any one of claims 1 to 3, wherein the paraffinic gas oil comprises more than 95 wt.% paraffins, preferably more than 98 wt.% paraffins, based on the total weight of the paraffinic gas oil. [5] 5. The use according to any one of claims 1 to 4, wherein the paraffinic gas oil is selected from Fischer-Tropsch derived gas oils and hydrotreated vegetable oil (HVO) derived gas oils, and mixtures thereof. [6] 6. Use according to any one of claims 1 to 5, wherein the paraffinic gas oil is a Fischer-Tropsch derived gas oil. [7] 7. The use according to claim 5 or 6, wherein the Fischer-Tropsch derived gas oil is present at a level of from 50% v / v to 100% v / v, based on the total diesel fuel composition. [8] The Fischer-Tropsch derived gas oil has a viscosity of 2.0 to 5.0 mmHg at 40°C. 2 / sec range, and kinematic viscosity of 0.76 to 0.80 g / cm3 The use according to any one of claims 5 to 7, having a density in the range of [9] 9. The use according to any one of claims 1 to 8, wherein the diesel fuel composition further comprises a diesel-based fuel.

[10] 1. A method for reducing the amount of SCR reagent required by an SCR system installed in a compression ignition internal combustion engine, the method comprising introducing into the engine a diesel fuel composition comprising a paraffinic gas oil.

[11] Use of a paraffinic gas oil in a diesel fuel composition to reduce the number of SCR reagent vehicle fills per year.

Claims

1. 1. Use of a paraffinic gas oil in a diesel fuel composition to reduce the number of SCR reagent vehicle fills per year, comprising: The number of SCR reagent vehicle fills per year is calculated by the following formula: [Equation 1] where: AAF = number of SCR reagent vehicle fills per year; SCR reagent consumption as a fraction of fuel consumption, taken as α=0.05 (i.e., 5%); AFC = Annual fuel consumption in litres; ATV = SCR reagent tank volume and the SCR reagent is selected from urea, ammonia, and ammonium salts, and mixtures thereof; The paraffinic gas oil comprises more than 95 wt. % paraffins based on the total weight of the paraffinic gas oil, the paraffinic gas oil is a Fischer-Tropsch derived gas oil, and the Fischer-Tropsch derived gas oil has a viscosity of 2.0 to 5.0 mm at 40°C. ２ / sec range, and 0.76 to 0.80 g / cm ３ having a density in the range of use.

2. The use according to claim 1, wherein the SCR reagent is urea.

3. 3. Use according to claim 1 or 2, wherein the paraffinic gas oil comprises more than 98% by weight of paraffins, based on the total weight of the paraffinic gas oil.

4. 4. Use according to any one of claims 1 to 3, wherein the Fischer-Tropsch derived gas oil is present at a level of from 50% v / v to 100% v / v, based on the total diesel fuel composition.

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

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