JP2009051875A - Low-sulfur diesel oil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide low-sulfur fuel oil suitable for a next-generation off-road diesel vehicle and having both of lubricity and low-temperature fluidity. <P>SOLUTION: The low-sulfur diesel oil has density of 0.7900-0.8200 g/cm<SP>3</SP>, a sulfur content of ≤10 ppm by mass, a nitrogen content of ≤10 ppm by mass, kinematic viscosity (30°C) of ≤2.00 mm<SP>2</SP>/s, a flash point of ≥40°C, an initial boiling point of ≥140°C, a 90% distillation temperature of ≤260°C, an HFRR of ≤460 μm, a cetane index of ≥45, a residual carbon content of 10% residual oil of ≤0.10 mass%, a pour point of ≤-45°C, a fatty acid lower alcohol ester content of 1.0-5.0 mass%, a triglyceride content of ≤0.01 mass%, a 1-4C lower alcohol content of ≤0.01 mass%, an acid number of ≤0.13 mgKOH/g, a total content of organic acids (formic acid, acetic acid and propionic acid) of ≤0.003 mass%, oxidation stability of ≤0.12 mgKOH/g and a gross calorific value of ≥36,660 kJ/L. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a low sulfur diesel fuel oil, and more particularly to a low sulfur diesel fuel oil for off-road use.

  In Japan, exhaust gas regulations for diesel vehicles, especially large diesel cars, have been strengthened from the viewpoint of achieving environmental standards, but exhaust gas regulations for off-road (or non-road) diesel engines such as construction machinery and agricultural machinery will also be strengthened. In motion. In order to comply with these exhaust gas regulations, new technical development and popularization are expected in fuel injection devices and exhaust gas aftertreatment devices used in off-road engines. The fuel oil used is also required to improve its characteristics in response to such trends, and various research and development are being continued.

For example, in Japanese Patent No. 3812853, the 10% residual carbon value is kept within the standard value, the engine output is not reduced, the 90% distillation temperature is not lowered below 310 ° C., and the entire range of the engine load. The invention for the purpose of providing a mixed fuel of light oil and vegetable oil that can significantly reduce the generation of particulates is described.
In claim 1, a 50% distillation temperature is 200 to 260 ° C., a mineral oil base that is a mixture of light oil and kerosene, and 30 to 80% of kerosene with respect to the total amount of the mineral oil base. It consists of 100 parts by volume of a mixed mineral oil base, 10 to 100 parts by volume of esterified vegetable oil, has a kinematic viscosity of 2.0 to 5.0 (mm ² / s, 30 ° C.), and a cetane number of 51 to 57. Diesel fuel is described.

Japanese Patent No. 3866380 describes an invention aimed at providing a diesel fuel oil composition having excellent exhaust gas purification performance without causing a reduction in fuel efficiency.
In claim 1, petroleum having a boiling point in the range of 90 to 150 ° C., an aromatic content of 1 to 10% by volume, a naphthene content of 5 to 40% by volume, and a sulfur content of 0.01% by weight or less. There is disclosed a diesel fuel oil composition characterized by containing 0.1 to 10% by volume of fraction A and 99.9 to 90% by volume of petroleum fraction B having a boiling point in the range of 150 to 370 ° C. .

JP 2006-257365 A discloses low sulfur gas oil having a sulfur content of 10 mass ppm or less, which suppresses filter clogging at a low temperature and has good low-temperature startability, reduced exhaust gas performance and excellent environmental pollution. An invention has been described which aims to provide a light oil composition having fuel efficiency characteristics and smooth operability at low temperatures and normal temperatures.
In claim 1, sulfur content is 10 mass ppm or less, slow cooling cloud point is -30.0 ° C to -13.0 ° C, pour point is -30.0 ° C or less, clogging point is -19 ° C or less, A cetane index of 45.0 or more, a kinematic viscosity at 30 ° C. of 1.7 to 4.0 mm ² / s, a flash point of 45 ° C. or more, a distillate at 180 ° C. (E180) and a distillate at 280 ° C. (E280 ) (E280-E180) is 55 to 75 vol%, the difference between the distillation amount (E300) at 300 ° C and the distillation amount (E350) at 350 ° C (E350-E300) is 20 vol% or less, and -29 ° C. A gas oil composition characterized by having a wax permeability of 10% or more is described.
Japanese Patent No. 3812853 Japanese Patent No. 3866380 JP 2006-257365 A

  By the way, as diesel fuel, it is common to use kerosene or A heavy oil in addition to light oil for on-road use and light oil for off-road use. Among them, kerosene and heavy oil A are frequently used in off-road use in Japan. However, taking into account future strengthening of environmental regulations, the following inconveniences may occur in relation to fuel injection devices and exhaust gas aftertreatment devices that will be used for off-road diesel .

Kerosene is a relatively low-sulfur fuel, but the standard value specified in the JIS standard (JIS K 2203) is only regulated to 0.008% by mass or less, so it has an effect on exhaust gas aftertreatment devices such as DPF. Concerned. Moreover, since the lubricity is low, there is a concern about the adverse effects such as wear in the latest fuel injection devices such as fuel pumps and common rails.
Furthermore, since kerosene has a lower flash point and a calorific value per unit capacity than diesel oil and A heavy oil, further improvement is desired.

  When using heavy oil A, it is considered essential to install DPF as a post-treatment device to comply with exhaust gas regulations, but due to the large amount of sulfur content, clogging of DPF occurs frequently. It will be. In addition, since there are many aromatic components, it is difficult to control PM and NOx in the exhaust gas.

In the case of light oil, there is no problem even if it is used for off-road use, but since it is expensive compared to kerosene and heavy fuel oil A, it is desired to develop fuels other than light oil.
Further, since the off-road fuel is used at a lower temperature as compared with the use environment of the on-road fuel, a fuel having further excellent low-temperature characteristics than the light oil is desired.

  For this reason, fuel oil for off-road diesel suitable for the latest fuel injection devices such as common rails and aftertreatment devices, which are expected to become popular in the future due to stricter exhaust gas regulations, has low lubricity and low-temperature fluidity. Although it is considered that the fuel oil is a sulfur fuel oil, or a fuel oil having a higher flash point and a calorific value per unit capacity, no fuel oil satisfying such characteristics has yet been provided. Therefore, an object of the present invention is to provide a low-sulfur fuel oil that is suitable for next-generation off-road diesel engines and has both lubricity and low-temperature fluidity, as well as safety and high calorific value.

  As a result of intensive studies to solve the above problems, the present inventor has found that petroleum hydrocarbons having a specific density, kinematic viscosity, flash point, distillation properties, etc. and biodiesel 1.0% by mass to 5.0% by mass. It has been found that a diesel fuel oil satisfying desired properties can be obtained by blending the following: The petroleum hydrocarbon having a specific density, kinematic viscosity, flash point, distillation properties, etc. is a light high flash point high calorific value hydrocarbon and / or desulfurized kerosene described later.

In one aspect, the present invention completed based on such knowledge has a density of 0.7900 to 0.8200 g / cm ³ , a sulfur content of 10 mass ppm or less, a nitrogen content of 10 mass ppm or less, and a kinematic viscosity (30 ° C.). Of 2.00 mm ² / s or less, flash point of 40 ° C. or more, initial boiling point of 140 ° C. or more, 90% distillation temperature of 260 ° C. or less, HFRR of 460 μm or less, cetane index of 45 or more, and 10% residual oil. The residual carbon content is 0.10% by mass or less, the pour point is −45 ° C. or less, the lower alcohol ester having 1 to 4 carbon atoms of the fatty acid is 1.0% by mass to 5.0% by mass, and the triglyceride content is 0.00. 01% by mass or less, C1-C4 lower alcohol content is 0.01% by mass or less, acid value is 0.13 mg KOH / g or less, and organic acid (sum of formic acid, acetic acid, propionic acid) is 0.003% by mass %, Oxidation stable There 0.12mgKOH / g or less, the total calorific value is 36,660kJ / L or more diesel fuel oil.

In yet another embodiment, the diesel fuel according to the present invention has a density of 0.8100 g / cm ³ or more, a flash point of 62 ° C. or more, and a total calorific value of 37,200 kJ / L or more. According to this embodiment, it has the same level of safety as heavy oil A, and has high lubricity, ignitability, and low temperature fluidity.

  According to the present invention, it is possible to provide a low sulfur fuel oil having both lubricity and low temperature fluidity. The fuel oil according to the present invention is suitable for next-generation off-road diesel, which is expected to spread in the future.

Light high flash point High calorific value Hydrocarbon (Base material A)
In the present invention, light high flash point high calorific value hydrocarbon is a raffinate obtained as a residue from a normal paraffin production apparatus, initial boiling point is 170-210 ° C, 90% distillation temperature is 220-260 ° C, This refers to a fraction having a sulfur content of 10 mass ppm or less and a nitrogen content of 10 mass ppm or less. Light high flash point high calorific value hydrocarbons are light in order to improve low temperature characteristics in fuel oil, and can play a role such as increasing the calorific value, raising the flash point and improving safety.

Normal paraffin production equipment is a device that adsorbs and separates normal paraffin from distillates such as naphtha, kerosene and light oil, etc. by iso-sieve method, molex method, urea adduct method, newrex method, etc., light high flash point high calorific value hydrocarbon Is the residue. The light high flash point high calorific value hydrocarbons mainly contain isoparaffins and aromatics, and the light high flash point high calorific value hydrocarbons used in the present invention preferably contain at least 70% isoparaffins.
The light high flash point and high calorific value hydrocarbon used in the present invention has an initial boiling point of 170 to 210 ° C, preferably 180 to 200 ° C, more preferably 185 to 195 ° C. This is due to the reason for ensuring low temperature fluidity. Moreover, 90% distillation temperature is 220-260 degreeC, Preferably it is 230-250 degreeC, More preferably, it is 235-245 degreeC. This is due to the reason for securing the heat generation amount. The light high flash point high calorific value hydrocarbon has a high flash point and is generally 65 to 75 ° C, preferably 67 to 75 ° C, more preferably 70 to 75 ° C. Further, the light high flash point high calorific value hydrocarbon has a high total calorific value, generally 37,000 kJ / L or more, preferably 37,200 kJ / L or more, more preferably 37,300 kJ / L or more. 37,000 to 37,500 kJ / L.

In addition, light high flash point high calorific value hydrocarbons typically have a density of 0.80 to 0.82 g / cm ³ , a sulfur content of 1 mass ppm or less, a nitrogen content of 1 mass ppm or less, and a 10% residual oil. Residual carbon content is 0.10% by mass or less, kinematic viscosity (30 ° C.) is 1.5 to 1.8 mm ² / s, cetane index is 45 to 50, acid value is 0.12 mgKOH / g or less, and HFRR is 600 to 800 μm, pour point is −70 to −90 ° C.

Desulfurized kerosene (Base material B)
In the present invention, desulfurized kerosene (base material B) has an initial boiling point of 140 to 170 ° C. and a 90% distillation temperature of 210 to 210 obtained by hydrorefining straight-run kerosene distilled from an atmospheric distillation apparatus. It refers to a fraction at 260 ° C., a sulfur content of 10 ppm or less, and a nitrogen content of 10 mass ppm or less. Desulfurized kerosene can play a role in improving low-temperature fluidity in fuel oil.

  The straight-run kerosene has an initial boiling point of 140 to 170 ° C, preferably 140 to 160 ° C, more preferably 140 to 150 ° C. This is due to the reason for ensuring low temperature fluidity. Moreover, 90% distillation temperature is 210-260 degreeC, Preferably it is 220-260 degreeC, More preferably, it is 230-260 degreeC. This is due to the reason for securing the heat generation amount.

In addition, desulfurized kerosene typically has a density of 0.79 to 0.80 g / cm ³ , sulfur content of 5 to 10 mass ppm, nitrogen content of 1 mass ppm or less, flash point of 40 to 45 ° C., 10% remaining The residual carbon content of the oil is 0.10% by mass or less, the kinematic viscosity (30 ° C.) is 1.2 to 1.4 mm ² / s, the cetane index is 45 to 50, the acid value is 0.12 mgKOH / g or less, and the HFRR is 600-800 micrometers, a total calorific value is 36,600-37,000 kJ / L, and a pour point is -45-55 degreeC.

Biodiesel (Base material C)
In the present invention, biodiesel refers to a fatty acid lower alcohol ester produced by chemical treatment using biological oils such as vegetable oil, animal oil, and fish oil. The fatty acid lower alcohol ester in the present invention refers to an ester of a linear or branched alcohol having 1 to 4 carbon atoms and a fatty acid, such as fatty acid methyl ester, fatty acid ethyl ester, fatty acid propyl ester, fatty acid butyl. Esters or mixtures thereof. In terms of oxidation stability and yield, the fatty acid lower alcohol ester is preferably a fatty acid methyl ester, a fatty acid ethyl ester, or a mixture thereof, and particularly preferably a fatty acid methyl ester. Since the diesel fuel oil according to the present invention is produced by blending biodiesel, when using biodiesel produced from fats and oils derived from vegetable oil, it is also effective as a measure against carbon dioxide reduction, that is, global warming countermeasures. In addition, the addition of biodiesel has the advantage of improving lubricity and increasing the amount of heat generated.

  Vegetable oils include, but are not limited to, corn oil, soybean oil, olive oil, rapeseed oil, sesame oil, peanut oil, jatropha oil and palm oil. Examples of animal oils include, but are not limited to, liver oil, whale oil, beef tallow, beef tallow, horse oil, pork oil, and sheep fat. Fish oils include, but are not limited to, salmon oil, salmon oil, salmon oil, squid oil, saury oil.

  Such esterified fats and oils can be produced using any means known to those skilled in the art. For example, the above fats and oils are reacted with lower alcohols such as methanol and ethanol in the presence of acid or alkali, and purified by washing or the like. Can be manufactured by a method.

The blending amount of biodiesel in the fuel oil is 1.0% by mass or more in total from the viewpoint of improving lubricity and improving the calorific value. However, the quality of biodiesel is likely to deteriorate, and there is a risk of clogging of the filter due to the generation of sludge. Therefore, when biodiesel is blended with the diesel fuel oil according to the present invention, the content in the fuel oil is suppressed to 5.0% by mass in total, and especially fatty acid methyl ester is 5.0% by mass or less. It is preferable to do this.
Moreover, it is preferable that the triglyceride in a fuel oil is 0.01 mass% or less, and methanol is 0.01 mass% or less. This is necessary to maintain oxidative stability.
The acid value is 0.13 mgKOH / g or less, the organic acid (the sum of formic acid, acetic acid and propionic acid) is 0.003% by mass or less, and the oxidation stability as a fuel oil is 0.12 mgKOH / g or less. preferable. This can be achieved by adding an antioxidant to the fatty acid methyl ester.

Fuel oil In one embodiment, the diesel fuel according to the present invention comprises 95.0% by mass or more and 99.0% by mass or less of a light high flash point high calorific value hydrocarbon and desulfurized kerosene, and biodiesel. 1.0 mass% or more and 5.0 mass% or less.
The diesel fuel according to this embodiment generally has a density of 0.7900 to 0.8200 g / cm ³ , a sulfur content of 10 mass ppm or less, a nitrogen content of 10 mass ppm or less, and a kinematic viscosity (30 ° C.) of 2.00 mm ^2. / S or less, flash point of 40 ° C. or higher, initial boiling point of 140 ° C. or higher, 90% distillation temperature of 260 ° C. or lower, HFRR of 460 μm or lower, cetane index of 45 or higher, residual carbon content of 10% residual oil is 0 .10% by mass or less, pour point is −45 ° C. or less, fatty acid lower alcohol ester is 1.0% by mass or more and 5.0% by mass or less, triglyceride is 0.01% by mass or less, and a lower alcohol having 1 to 4 carbon atoms. 0.01% by mass or less, organic acid (total amount of formic acid, acetic acid, propionic acid) is 0.003% by mass, and total calorific value is 36,660 kJ / L or more.

In yet another embodiment of the diesel fuel according to the present invention, the diesel fuel oil according to the present invention comprises 95.0 mass% or more and 99.0 mass% or less of light high flash point high calorific value hydrocarbon and biodiesel. 1.0 mass% or more and 5.0 mass% or less.
The diesel fuel oil according to this embodiment generally has a density of 0.8100 to 0.8200 g / cm ³ , a sulfur content of 10 mass ppm or less, a nitrogen content of 10 mass ppm or less, and a kinematic viscosity (30 ° C.) of 2.00 mm. ² / s or less, flash point 62 ° C. or higher, initial boiling point 170 ° C. or higher, 90% distillation temperature 260 ° C. or lower, HFRR 460 μm or lower, cetane index 45 or higher, 10% residual carbon residual carbon content It may have 0.10% by mass or less, a pour point of −50 ° C. or less, and a total calorific value of 37,200 kJ / L or more.
The density is typically 0.8100 to 0.8150 g / cm ³ .
The sulfur content is preferably 5 ppm by mass or less, more preferably 1 ppm by mass or less.
The nitrogen content is preferably 5 ppm by mass or less, more preferably 1 ppm by mass or less.
The kinematic viscosity is preferably 1.80 mm ² / s or less, more preferably 1.70 mm ² / s or less, and typically 1.60 to 1.80 mm ² / s.
The flash point is preferably 65 ° C. or higher, more preferably 70 ° C. or higher, and typically 65 to 75 ° C.
The initial boiling point is typically 180 to 200 ° C.
The 90% distillation temperature is preferably 250 ° C. or lower, and typically 230 to 250 ° C.
The HFRR is preferably 450 μm or less, and is typically 410 to 450 μm.
The cetane index is 45-50 in the typical example, more typically 45-48, and even more typically 45-46.
The residual carbon content of 10% residual oil is preferably 0.05% by mass or less, more preferably 0.01% by mass or less.
The pour point is preferably −60 ° C. or lower, more preferably −70 ° C. or lower, and typically −60 to −80 ° C.
The total calorific value is preferably 37,300 kJ / L or more, more preferably 37,400 kJ / L or more, and typically 37,200 to 37,500 kJ / L.

  In yet another embodiment of the diesel fuel according to the present invention, the diesel fuel oil according to the present invention comprises desulfurized kerosene in an amount of 95.0 mass% to 99.0 mass% and biodiesel in an amount of 1.0 mass% to 5. 0% by mass or less.

The diesel fuel oil according to this embodiment generally has a density of 0.7900 to 0.8000 g / cm ³ , a sulfur content of 10 mass ppm or less, a nitrogen content of 10 mass ppm or less, and a kinematic viscosity (30 ° C.) of 1.70 mm. ² / s or less, flash point of 40 ° C. or higher, initial boiling point of 140 ° C. or higher, 90% distillation temperature of 260 ° C. or lower, HFRR of 450 μm or lower, cetane index of 45 or higher, residual carbon content of 10% residual oil It may have 0.10% by mass or less, a pour point of −45 ° C. or less, and a total calorific value of 36,660 kJ / L or more.
The density is typically 0.7950 to 0.8000 g / cm ³ .
The sulfur content is preferably 8 ppm by mass or less, and is typically 4 to 8 ppm by mass.
The nitrogen content is preferably 5 ppm by mass or less, more preferably 1 ppm by mass or less.
Kinematic viscosity preferably not more than 1.60 mm ² / s, more preferably not more than 1.50 mm ² / s, a typical example is a 1.30~1.60mm ² / s.
The flash point is preferably 42 ° C. or higher, and is typically 42 to 45 ° C.
The initial boiling point is typically 150 to 170 ° C.
The 90% distillation temperature is typically 240-260 ° C.
The HFRR is preferably 430 μm or less, more preferably 410 μm, and typically 400 to 430 μm.
The cetane index is preferably 45-50, typically 46-48.
The residual carbon content of 10% residual oil is preferably 0.05% by mass or less, more preferably 0.01% by mass or less.
The pour point is typically −45 to −60 ° C., more typically −45 to −50 ° C.
The total calorific value is preferably 36,800 kJ / L or more, and is typically 36,600-37,000 kJ / L in a typical example.

  Furthermore, the diesel fuel oil of the present invention may contain one or more fuel oil additives known in the art as needed. Although these compounding quantities can be selected suitably, in order to suppress an engine deposit production | generation, it is usually preferable to maintain the total compounding quantity of an additive at 0.1 weight% or less. Examples of the fuel oil additive that can be used in the diesel fuel oil of the present invention include an ethylene-vinyl acetate copolymer, an ethylene-alkyl acrylate copolymer, a polymer system such as polyalkyl acrylate, and an interface such as an alkenyl succinic acid amide. An activator-type low-temperature fluidity improver, an alkyl nitrate-based cetane number improver, a fatty acid-based or ester-based lubricity improver, and the like can be mentioned.

Various parameters used in the present specification refer to those measured in accordance with the following method.
Density: Method specified at JIS K 2249 “Crude oil and petroleum product density test method” (15 ° C.)
Sulfur content: Method specified in JIS K 2541-6 “Sulfur content test method (ultraviolet fluorescence method)” Nitrogen content: Method specified in JIS K 2609-4 “Nitrogen content test method (chemiluminescence method)” Kinematic viscosity: Method specified at JIS K2283 “Kinematic viscosity test method” (30 ° C.)
Flash point: Method defined in JIS K 2265-1 “Method of obtaining flash point” Distillation property: Method defined in JIS K 2254 “Fuel oil distillation test method” HFRR: JIS-5S-50-98 “Light oil— Method stipulated in "Lubricity test method" Cetane index: JIS K 2280 "Petroleum products-Fuel oil-Octane number and cetane number test method and cetane index calculation method" 10% residual carbon residual carbon content: JIS Method stipulated in K 2270 “Residual carbon content test method” Pour point: Method stipulated in JIS K 2269 “Crude point and petroleum product cloud point test method of crude oil and petroleum products” Total calorific value: JIS K 2279 “Exotherm” Method specified in "Quantity test method" Fatty acid methyl ester: Liquid chromatography method Triglyceride: Liquid chromatography method Tanol: Oxygen detection type gas chromatographic method Acid value: Method specified in JIS K 2501 “Neutralization number test method” Organic acid: Water extraction ion chromatographic method Oxidation stability: In the oxidation stability test of ISO12205, the sample temperature The temperature is changed from 95 ° C. to 115 ° C., and oxygen is supplied into 350 mL of the sample at a supply rate of 3 L / h and a supply pressure of 98 kPa for 16 hours, and then the sample is cooled with ice and returned to room temperature. The value obtained by subtracting the acid value before the test from the acid value after the oxidation test is defined as oxidation stability.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited thereto.

The hydrocarbon fuel oil base materials shown in Table 1 were prepared. Each substrate was prepared by the following method.
Substrate A: a light high flash point high calorific value hydrocarbon distilled from a normal paraffin production apparatus, a fraction having an initial boiling point of 190 ° C. and a 90% distillation temperature of 237 ° C.

Base material B: a fraction obtained by hydrorefining straight-run kerosene distilled from an atmospheric distillation apparatus, having an initial boiling point of 147 ° C. and a 90% distillation temperature of 244 ° C.

Substrate C: Fatty acid methyl ester obtained by transesterification of palm oil with methanol, a fraction having an initial boiling point of 313 ° C. and a 90% distillation temperature of 344 ° C.

  The base materials shown in Table 1 were blended at a predetermined ratio to prepare hydrocarbon fuel oils to be examples 1 and 2. The results are shown in Table 3. Table 2 shows the properties of commercially available heavy oil A and kerosene.

Claims (5)

The density is 0.7900 to 0.8200 g / cm ³ , the sulfur content is 10 mass ppm or less, the nitrogen content is 10 mass ppm or less, the kinematic viscosity (30 ° C.) is 2.00 mm ² / s or less, and the flash point is 40 ° C. or more. The initial boiling point is 140 ° C. or higher, the 90% distillation temperature is 260 ° C. or lower, the HFRR is 460 μm or lower, the cetane index is 45 or higher, the residual carbon content of 10% residual oil is 0.10% by mass or less, and the pour point is − 45 ° C. or less, fatty acid lower alcohol ester of 1.0% by mass or more and 5.0% by mass or less, triglyceride content of 0.01% by mass or less, and C 1-4 lower alcohol content of 0.01% by mass or less The acid value is 0.13 mgKOH / g or less, the organic acid (sum of formic acid, acetic acid and propionic acid) is 0.003% by mass or less, the oxidation stability is 0.12 mgKOH / g or less, and the total calorific value is 36,660 kJ / L. More low sulfur Diesel fuel oil. The low-sulfur diesel fuel oil according to claim 1, having a density of 0.8100 g / cm ³ or more, a flash point of 62 ° C or more, and a total calorific value of 37,200 kJ / L or more.   The low-sulfur diesel fuel oil according to claim 1 or 2, wherein the fatty acid lower alcohol ester is a fatty acid methyl ester, a fatty acid ethyl ester, or a mixture thereof.   The low-sulfur diesel fuel oil according to any one of claims 1 to 3, wherein the lower alcohol is methanol, ethanol or a mixture thereof.   The low-sulfur diesel fuel oil according to any one of claims 1 to 4, which is used for off-road diesel.