Fuel oil composition and method for producing same

Abstract

The present invention provides a fuel oil composition and a method for producing the same, the fuel oil composition containing a fatty acid alkyl ester and a decomposed gas oil fraction having specific properties in specific amounts based on the total amount of the composition, such that by containing the fatty acid alkyl ester and the decomposed gas oil fraction in prescribed amounts, the fuel oil composition exhibits excellent fuel economy performance and combustion performance, environmental performance for reducing nitrogen oxide emissions, as well as excellent storage stability.

Description

Fuel oil composition and method for producing the same

[0001] The present invention relates to a fuel oil composition and a method for producing the same.

[0002] JIS K2205:1991 Type 1 heavy oil (hereinafter also referred to as "A heavy oil"), and especially JIS K2205:1991 Type 1 No. 1 heavy oil (hereinafter also referred to as "low sulfur A heavy oil"), have a higher calorific value per unit volume compared to kerosene, light oil, etc., allowing for a reduction in fuel oil usage (volume). Furthermore, compared to C heavy oil (JIS K2205:1991 Type 3 heavy oil), they have lower sulfur, nitrogen, and residual carbon content, resulting in a lower environmental impact. In addition, unlike C heavy oil, they do not require heating, can be stored and used at room temperature, and have excellent supply stability. For these reasons, they are widely used as fuel oil for internal combustion engines such as marine diesel engines and as fuel oil for external combustion engines such as power generation boilers.

[0003] Fuel oils for ships that satisfy ISO 8217 "Petroleunium products - Fuels (class F) - Specification of marine fuels" are known. ISO 8217:2017 added additional provisions (DF grades: DFA, DFZ, and DFB) for ship distillates with a maximum fatty acid methyl ester (FAME) content of 7% by volume or less. Fuel oil compositions containing fatty acid methyl ester (FAME) are known, for example, those described in Patent Documents 1 to 3. Patent Documents 1 to 3 disclose fuel oil compositions containing methyl esters of rapeseed oil, such as fatty acid methyl ester (e.g., methyl myristate), in a content of 5 to 100% by volume, which are used for internal combustion engines and external combustion engines.

[0004] Japanese Patent Publication No. 2007-231119, Japanese Patent Publication No. 2007-231120, Japanese Patent Publication No. 2007-231121

[0005] The fatty acid alkyl esters, such as fatty acid methyl esters (FAME), contained in the fuel oil compositions described in Patent Documents 1 to 3 above, are among the base oils whose use as fuel oils is being investigated due to their high combustion performance and fuel efficiency. Furthermore, when fatty acid alkyl esters derived from plants and animals are used, carbon dioxide emissions are reduced, thus contributing to the mitigation of global warming through carbon dioxide emission reduction, and are extremely useful from an environmental protection standpoint. Therefore, by using fatty acid alkyl esters such as fatty acid methyl esters (FAME) as a base oil, improved combustion performance can be expected, and by adopting fatty acid alkyl esters derived from plants and animals, it can become a base oil that contributes to environmental protection.

[0006] Incidentally, when using fuel oil compositions in internal combustion engines, such as marine diesel engines, the frequency of fuel oil filter clogging tends to increase during normal use due to sludge formation caused by asphaltene aggregation. Furthermore, when used after long-term storage in fuel oil tanks on ships, sludge formation becomes more likely, and the frequency of clogging tends to increase even further. As fuel oil compositions for ships, fuel oils that satisfy ISO 8217 as described above are known, but fuel oil filter clogging can still occur. As methods to reduce the frequency of clogging, methods such as reducing the latent sediment (Total sediment aged, ISO 10307-2) to 0.10% by mass or less, and methods such as reducing the actual sediment (Total sediment by hot filtration, ISO 10307-1) to 0.10% by mass or less are known. However, for fuel oils used in ships, especially distillates, the oil flow performance in fuel oil filters after storage at room temperature is not sufficient, and there is a need for fuel oil compositions that can further reduce the frequency of blockage. Reducing the frequency of blockage in fuel oil filters reduces the frequency of cleaning the fuel oil filters, which in turn enables more stable operation. Thus, storage stability is required for fuel oil compositions used in internal combustion engines of ships and the like, but storage stability is also required for fuel oil compositions used in external combustion engines, just as it is for internal combustion engines.

[0007] The fuel oil compositions described in the above-mentioned Patent Documents 1 to 3 focus on reducing unburned substances (smoke) and particulate matter (PM) in exhaust gas, improving calorific value and reducing soot concentration in combustion exhaust gas, and improving sludge stability due to the reduction of sulfur content and the inclusion of residual carbon imparting agents. However, they do not focus on improving fuel flow performance by reducing the frequency of clogging, in addition to improving combustion performance, and there is room for improvement in the fuel flow performance in fuel oil filters after storage at room temperature (hereinafter also referred to as "storage stability performance"). Furthermore, while ISO 8217 sets standards for ship distillate oil with a fatty acid methyl ester (FAME) content of 7% by volume or less, it makes no mention of low-sulfur heavy oil A exceeding 7% by volume. Low-sulfur heavy oil A with a fatty acid alkyl ester content of fatty acid methyl ester (FAME) or other exceeding 7% by volume is prone to clogging of fuel oil filters when used after storage at room temperature, and cannot be said to have excellent storage stability performance. Therefore, further improvements are needed to enhance storage stability performance by reducing the frequency of fuel oil filter blockage when using the fuel after storage at room temperature.

[0008] Furthermore, the fatty acid alkyl esters used in the fuel oil compositions described in the above-mentioned Patent Documents 1 to 3 have excellent combustion performance and fuel efficiency, as previously mentioned, but generally nitrogen oxides (NOx) are used. Ｘ It is known that emissions of nitrogen oxides (NOx) tend to increase when fatty acid alkyl esters are used in fuel oil compositions. Ｘ There is a trade-off between reducing emissions and environmental performance. In recent years, reducing environmental impact has become an urgent issue, and there is a strong demand for improved environmental performance.

[0009] Thus, fuel oil compositions for internal and external combustion engines should have properties that contribute to stable navigation, such as combustion performance, fuel efficiency, and storage stability, as well as nitrogen oxides (NOx). ＸThere is a desire to provide a fuel oil composition that is excellent in environmental performance and reduces the emissions of (). For example, external combustion engines equipped with hydraulic atomizing burners with a rated combustion volume of 100 L / h or less are subject to strict cost management, so it is difficult to install denitration equipment for reducing or removing nitrogen oxides (NO Ｘ ). Therefore, it is extremely useful that the fuel oil composition used for such external combustion engines is excellent in environmental performance that reduces the emissions of nitrogen oxides (NO Ｘ ). In addition, regarding environmental performance, not only the performance of reducing the emissions of nitrogen oxides (NO Ｘ ), but also environmental performance capable of reducing the sulfur content required for conventional fuel oil compositions is required.

[0010] The present invention has been made in view of such circumstances, and by containing a fatty acid alkyl ester and a cracked gas oil fraction in predetermined contents, it is excellent in fuel consumption performance and combustion performance, and reduces the emissions of nitrogen oxides. It aims to provide a fuel oil composition that is excellent in environmental performance and also in storage stability.

[0011] As a result of intensive studies in view of the above problems, the present inventors have found that the following invention can solve the problems. That is, the present invention provides a fuel oil composition having the following configuration.

[0012] [1] A fatty acid alkyl ester that satisfies all of the following (a １ )-(a ３ ), and a cracked gas oil fraction that satisfies all of the following (b １ )-(b ４ ), the fatty acid alkyl ester being an ester of a fatty acid having 8 to 22 carbon atoms and an alkyl alcohol having 1 to 4 carbon atoms, the content of the fatty acid alkyl ester based on the total amount of the composition being 15.0% by volume or more and 35.0% by volume or less, and the content of the cracked gas oil fraction based on the total amount of the composition being more than 40.0% by volume and 60.0% by volume or less, a fuel oil composition that satisfies any of the following (1)-(6). (a １ ) The cetane number is 49.0 or more (a ２ ) The acid value is 0.50 mgKOH / g or less (a ３) The residual carbon content of the 10% residual oil is 0.80% by mass or more and 1.50% by mass or less (b １ ) The kinematic viscosity at 50°C is 2,600 mm ２ / s or more 3.600mm ２ / s or less (b ２ ) Sulfur content is 0.400% by mass or less (b ３ ) Aromatic content of 50.0% by volume or more (b ４ ) Aromatic content of three or more rings is 10.0% by volume or more (1) Density at 15℃ is 0.8950 g / cm³ ３ (2) The kinematic viscosity at 50°C is 3,000 mm². ２ / s or more 3.500mm ２ [1] The fuel oil composition according to [1] above, wherein the fatty acid alkyl ester is a fatty acid methyl ester. [2] The fuel oil composition according to [1] above, wherein the fatty acid is a mixed fatty acid containing two or more fatty acids having 8 or more carbon atoms and 22 carbon atoms. [3] The fuel oil composition according to [1] above, wherein the fatty acid is a mixed fatty acid containing two or more fatty acids having 8 or more carbon atoms and 22 carbon atoms. [4] The fuel oil composition according to [3] above, wherein the mixed fatty acid is obtained from at least one raw material selected from animal oil and vegetable oil. [5] The fuel oil composition according to any one of [1] to [4] above, used in an external combustion engine. [6] The fuel oil composition according to [5] above, wherein the external combustion engine is equipped with a hydraulic spray burner with a rated combustion rate of 100 L / hour or less. [7] An ester of a fatty acid having 8 to 22 carbon atoms and an alkyl alcohol having 1 to 4 carbon atoms, as follows (a １ ) ~ (a ３ ) an alkyl fatty acid ester that satisfies all of the following conditions and (b １ ) ~ (b ４ A method for producing a fuel oil composition that satisfies all of the following (1) to (6): (a) １ ) Cetane number of 49.0 or higher (a２ ) Acid value is 0.50 mg KOH / g or less (a ３ ) The residual carbon content of the 10% residual oil is 0.80% by mass or more and 1.50% by mass or less (b １ ) The kinematic viscosity at 50°C is 2,600 mm ２ / s or more 3.600mm ２ / s or less (b ２ ) Sulfur content is 0.400% by mass or less (b ３ ) Aromatic content of 50.0% by volume or more (b ４ ) Aromatic content of three or more rings is 10.0% by volume or more (1) Density at 15℃ is 0.8950 g / cm³ ３ (2) The kinematic viscosity at 50°C is 3,000 mm². ２ / s or more 3.500mm ２ / s or less (3) Sulfur content is 0.300% by mass or less (4) Aromatic content of three or more rings is 6.0% by volume or more (5) Residual carbon content of 10% residual oil is 0.21% by mass or more and 0.60% by mass or less (6) Cetane number is 31.0 or higher

[0013] According to the present invention, by incorporating fatty acid alkyl esters and cracked light oil fractions in predetermined amounts, it is possible to provide a fuel oil composition that is excellent in fuel efficiency and combustion performance, as well as environmental performance that reduces nitrogen oxide emissions, and also has excellent storage stability.

[0014] The following describes in detail a fuel oil composition according to an embodiment of the present invention (hereinafter sometimes simply referred to as "this embodiment"). In this specification, the numerical values ​​related to "less than or equal to," "greater than or equal to," and "and" in relation to numerical ranges can be any combination. For example, if a certain numerical range is described as "A to B" and "C to D," it also includes numerical ranges such as "A to D" and "C to B." Furthermore, the numerical values ​​in the examples can be used as upper or lower limits.

[0015] [Fuel Oil Composition] The fuel oil composition of this embodiment is as follows (a １ ) ~ (a ３ ) an alkyl fatty acid ester that satisfies all of the following conditions and (b １ ) ~ (b ４A fuel oil composition that satisfies all of the following (1) to (6): (a) a cracked light oil fraction that satisfies all of the following: (a) a fatty acid alkyl ester is an ester of a fatty acid having 8 to 22 carbon atoms and an alkyl alcohol having 1 to 4 carbon atoms, the content of the fatty acid alkyl ester on a basis of the total composition is 15.0% by volume or more and 35.0% by volume or less, and the content of the cracked light oil fraction on a basis of the total composition is more than 40.0% by volume and 60.0% by volume or less. １ ) Cetane number of 49.0 or higher (a ２ ) Acid value is 0.50 mg KOH / g or less (a ３ ) The residual carbon content of the 10% residual oil is 0.80% by mass or more and 1.50% by mass or less (b １ ) The kinematic viscosity at 50°C is 2,600 mm ２ / s or more 3.600mm ２ / s or less (b ２ ) Sulfur content is 0.400% by mass or less (b ３ ) Aromatic content of 50.0% by volume or more (b ４ ) Aromatic content of three or more rings is 10.0% by volume or more (1) Density at 15℃ is 0.8950 g / cm³ ３ (2) The kinematic viscosity at 50°C is 3,000 mm². ２ / s or more 3.500mm ２ / s or less (3) Sulfur content is 0.300% by mass or less (4) Aromatic content of three or more rings is 6.0% by volume or more (5) Residual carbon content of 10% residual oil is 0.21% by mass or more and 0.60% by mass or less (6) Cetane number is 31.0 or higher

[0016] (Composition and properties of the fuel oil composition) The fuel oil composition of this embodiment satisfies all of the following compositions and properties as defined in (1) to (6). (1) Density at 15°C The density of the fuel oil composition of this embodiment at 15°C is 0.8950 g / cm³ ３ That concludes the explanation. If the density at 15°C is outside the above range, a decrease in combustion performance, fuel efficiency, and storage stability may occur.

[0017] From the viewpoint of improving combustion performance, fuel efficiency, and storage stability, the density of the fuel oil composition of this embodiment at 15°C is preferably 0.8960 g / cm³.３ The above is a more preferable 0.8980 g / cm³. ３ More preferably, 0.9000 g / cm³ ３ The above is true, with a preferred upper limit of 0.9200 g / cm³. ３ More preferably, 0.9150 g / cm³ ３ The following applies: In this specification, the density at 15°C is the value measured in accordance with JIS K 2249-1:2011 (Crude oil and petroleum products - Method for determining density - Part 1: Vibration method).

[0018] (2) Kinematic viscosity at 50°C The kinematic viscosity of the fuel oil composition of this embodiment at 50°C is 3,000 mm ２ / s or more 3.500mm ２ It is less than or equal to / s. If the kinematic viscosity at 50°C is outside the above range, combustion performance and environmental performance in reducing nitrogen oxide emissions may decrease. In addition, it may become difficult to use it in the operating range of various equipment such as pumps and flow meters, and lubrication may not be ensured, making it unsuitable for use as a fuel oil composition.

[0019] The kinematic viscosity of the fuel oil composition of this embodiment at 50°C is preferably 3,100 mm, from the viewpoint of improving combustion performance and environmental performance, making it easier to adapt to the operating range of various equipment, and improving lubricity. ２ / s or more, more preferably 3,200 mm ２ The value is 1 / s or more, and preferably has an upper limit of 3,400 mm. ２ / s or less, more preferably 3.350 mm ２ It is less than or equal to / s. In this specification, the kinematic viscosity at 50°C is the value measured in accordance with JIS K 2283:2000 (Test method for kinematic viscosity of crude oil and petroleum products).

[0020] (3) Sulfur content The sulfur content of the fuel oil composition of this embodiment is 0.300% by mass or less. If the sulfur content is outside the above range, corrosion may occur due to an increase in sulfur oxides in the exhaust gas, and the environmental burden may increase, which may lead to a decrease in environmental performance.

[0021] Considering the suppression of corrosion and the improvement of environmental performance, the sulfur content is preferably 0.250% by mass or less, more preferably 0.200% by mass or less, and even more preferably 0.160% by mass or less. Furthermore, the lower the sulfur content, the better, and there is no particular lower limit, but from the viewpoint of improving storage stability and lubricity, it is usually 0.03% by mass or more. In this specification, the sulfur content other than fatty acid alkyl esters is measured by selecting a measurement method according to the content, and when the content is 0.01 to 5% by mass, the value is measured in accordance with JIS K 2541-4:2003 (Crude oil and petroleum products - Sulfur content test method - Part 4: Radiation excitation method).

[0022] (4) Content of aromatic compounds with three or more rings The content of aromatic compounds with three or more rings in the fuel oil composition of this embodiment is 6.0% by volume or more. If the content of aromatic compounds with three or more rings is not within the above range, the storage stability performance will decrease. From the viewpoint of improving the storage stability performance of the fuel oil composition, it is preferably 6.2% by volume or more, more preferably 6.5% by volume or more, and even more preferably 7.0% by volume or more, and there is no particular upper limit, but it is usually 10.0% by volume or less. In this specification, the content of aromatic compounds other than heavy oil fractions (residual carbon sources) described later (mono-ring aromatic compounds, bi-ring aromatic compounds and aromatic compounds with three or more rings), as well as the content of saturated compounds and olefin compounds, are values ​​measured by the High Performance Liquid Chromatography method, as specified in JPI-5S-49-2007, Petroleum Products - Hydrocarbon Type Test Method.

[0023] (5) Residual carbon content of 10% residual oil The residual carbon content of the 10% residual oil of the fuel oil composition of this embodiment is 0.21% by mass or more and 0.60% by mass or less. If the residual carbon content of the 10% residual oil exceeds 0.60% by mass, it becomes difficult to maintain combustion performance, sludge is more likely to form, and storage stability performance decreases. Furthermore, by setting it to 0.21% by mass or more, the fuel oil composition of this embodiment can be treated as heavy oil A and can be exempted from light oil tax, thus providing tax benefits. From the viewpoint of improving combustion performance and storage stability performance, and considering tax benefits, the residual carbon content of the 10% residual oil is preferably 0.22% by mass or more, more preferably 0.23% by mass or more, and as an upper limit, preferably 0.50% by mass or less, more preferably 0.45% by mass or less. In this specification, the residual carbon content of 10% residual oil is the value measured using 10% residual oil prepared in accordance with JIS K 2270-2:2009 (Crude oil and petroleum products - Method for determining residual carbon content - Part 2: Microscopic method) and Annex A.

[0024] (6) Cetane number The cetane number of the fuel oil composition of this embodiment is 31.0 or higher. If the cetane number is less than 31.0, the combustion performance will decrease. From the viewpoint of improving combustion performance, the cetane number is preferably 31.5 or higher, more preferably 32.0 or higher, and there is no particular upper limit, but it is usually 41.0 or lower. In this specification, the cetane number is a value determined in accordance with JIS K 2280-4:2013 (Petroleum products - Method for determining octane number, cetane number and cetane index - Part 4: Cetane number).

[0025] Furthermore, in addition to the properties and composition of (1) to (6) above, the fuel oil composition of this embodiment preferably satisfies at least one of the properties and composition selected from (7) to (13) below, and it is particularly preferable that it satisfies all of the properties and composition of (7) to (13) below.

[0026] (7) Flash point The flash point of the fuel oil composition of this embodiment is preferably 60.0°C or higher, more preferably 65.0°C or higher, and even more preferably 70.0°C or higher, from the viewpoint of handling safety. There is no particular upper limit, but it is usually 100.0°C or lower. In this specification, the flash points other than fatty acid alkyl esters are values ​​measured in accordance with JIS K 2265-3:2007 (Crude oil and petroleum products - Flash point test methods - Part 3: Pennsky-Haltens occlusion method).

[0027] (8) Moisture Content The moisture content of the fuel oil composition of this embodiment is preferably 0.10% by volume or less, more preferably less than 0.10% by volume. There is no particular lower limit, as a smaller value is preferable. When the moisture content is within the above range, the formation of sludge due to the emulsion of asphaltene and water, as well as the occurrence of freezing, etc., during storage at room temperature can be suppressed, thereby reducing the frequency of blockage in the fuel oil filter and improving storage stability performance. In this specification, the moisture content other than fatty acid alkyl esters is a value measured in accordance with JIS K 2275-1:2015 (Crude oil and petroleum products - Method for determining moisture - Part 1: Distillation method).

[0028] (9) Copper Plate Corrosion The copper plate corrosion of the fuel oil composition of this embodiment is preferably 1 or less (1a or 1b) in terms of the copper plate classification for copper plate determination, and more preferably 1a. If the copper plate corrosion is 1 or less, corrosion of the fuel oil tank, piping, diesel engine, and various auxiliary equipment such as pumps can be prevented, thereby enabling more stable operation of various equipment such as internal combustion engines and external combustion engines. In this specification, copper plate corrosion is measured in accordance with JIS K 2513:2000 (Petroleum products - Copper plate corrosion test method -). Here, the test temperature is 50°C and the test time is 3 hours.

[0029] (10) Acid Value The acid value of the fuel oil composition of this embodiment is preferably 0.15 mg KOH / g or less, more preferably 0.10 mg KOH / g or less, and even more preferably less than 0.10 mg KOH / g. The lower the acid value, the better, and there is no particular lower limit, but it is particularly preferably 0.0 mg KOH / g. When the acid value is within the above range, the frequency of blockage in the fuel oil filter can be reduced by suppressing sludge formation, thereby improving storage stability performance and further suppressing corrosion of storage tanks, piping and other components when stored at room temperature. In this specification, the acid value is a value measured in accordance with "7. Potentiometric titration method (acid value)" as specified in JIS K 2501:2003 (Petroleum products and lubricating oils - Neutralization value test method).

[0030] (11) Pour point The pour point of the fuel oil composition of this embodiment is preferably -10.0°C or lower, more preferably -12.5°C or lower, and even more preferably -15.0°C or lower. There is no particular lower limit, but it is usually -35.0°C or higher. When the pour point is within the above range, the fluidity in storage tanks and piping at low temperatures is improved, and handling is also improved. In this specification, the pour point is a value measured in accordance with JIS K 2269:1987 (Test method for the pour point of crude oil and petroleum products and the cloud point of petroleum products).

[0031] (12) Nitrogen content The nitrogen content of the fuel oil composition of this embodiment is preferably 250 ppm by mass or less, more preferably 230 ppm by mass or less, and even more preferably 200 ppm by mass or less. There is no particular lower limit, but it is usually 100 ppm by mass or more. When the nitrogen content is within the above range, nitrogen oxides (NO) Ｘ ) This reduces emissions, thus improving environmental performance. In this specification, the nitrogen content is a value measured in accordance with JIS K 2609:1998 (Crude oil and petroleum products - Test method for nitrogen content).

[0032] (13) Total calorific value The total calorific value of the fuel oil composition of this embodiment is preferably 38.7 MJ / L or more, more preferably 38.8 MJ / L or more, and even more preferably 38.9 MJ / L or more, with the upper limit being preferably higher, and usually 43.0 MJ / L or less. When the total calorific value is within the above range, fuel efficiency is improved. In this specification, the total calorific value is the value obtained by multiplying the "Gross heat of combustion" measured based on the test method specified in "Standard Test Method for Heat of Combustion of Liquid Hydrocarbon Fuels by Bomb Calorimeter" (ASTM D240-9) by the density and converting it to a value per volume.

[0033] (Alkyl fatty acid ester) The fuel oil composition of this embodiment is as follows (a １ ) ~ (a ３ (a) The composition satisfies all of the above conditions and contains a fatty acid alkyl ester, which is an ester of a fatty acid having 8 to 22 carbon atoms and an alkyl alcohol having 1 to 4 carbon atoms, in an amount of 15.0% to 35.0% by volume on a basis of the total amount of the composition. １ ) Cetane number of 49.0 or higher (a ２ ) Acid value is 0.50 mg KOH / g or less (a ３ ) The residual carbon content of the 10% residual oil is 0.80% by mass or more and 1.50% by mass or less.

[0034] (a １ The cetane number of the fatty acid alkyl ester is 49.0 or higher. Fatty acid alkyl esters are known as oils with a high cetane number, and by using fatty acid alkyl esters, the cetane number of the fuel oil composition of this embodiment can be improved, thereby improving combustion performance. Therefore, if the cetane number of the fatty acid alkyl ester is less than 49.0, it becomes difficult to make the cetane number of the fuel oil composition of this embodiment 31.0 or higher, and combustion performance decreases. From the viewpoint of improving combustion performance, the cetane number of the fatty acid alkyl ester is preferably 50.0 or higher, more preferably 51.0 or higher. There is no particular upper limit, and it is usually 70.0 or lower.

[0035] (a ２The acid value of the fatty acid alkyl ester is 0.50 mg KOH / g or less. If the acid value of the fatty acid alkyl ester is not within the above range, the suppression of sludge formation will increase the frequency of blockage in the fuel oil filter, which will reduce storage stability performance, and corrosion of storage tanks, piping, and other components may occur when stored at room temperature. From the viewpoint of improving storage stability performance and suppressing corrosion of components, the acid value of the fatty acid alkyl ester is preferably 0.48 mg KOH / g or less, more preferably 0.47 mg KOH / g or less, and even more preferably 0.46 mg KOH / g or less, with no particular lower limit, and is usually 0.05 mg KOH / g or more.

[0036] (a ３ ) Residual carbon content of 10% residual oil The residual carbon content of 10% residual oil of fatty acid alkyl ester is 0.80% by mass or more and 1.50% by mass or less. If the residual carbon content of 10% residual oil of fatty acid alkyl ester is not within the above range, it becomes difficult to make the residual carbon content of 10% residual oil of the fuel oil composition of this embodiment 0.21% by mass or more and 0.60% by mass or less, making it difficult to maintain combustion performance. In addition, it becomes difficult to reduce the frequency of blockage in the fuel oil filter, which may reduce storage stability performance. From the viewpoint of making it easier to make the residual carbon content of 10% residual oil of the fuel oil composition of this embodiment 0.21% by mass or more and 0.60% by mass or less, and improving combustion performance and storage stability performance, the residual carbon content of 10% residual oil of fatty acid alkyl ester is preferably 0.85% by mass or more, more preferably 0.90% by mass or more, with an upper limit of preferably 1.40% by mass or less, more preferably 1.30% by mass or less, even more preferably 1.15% by mass or less, and even more preferably 1.00% by mass or less. Furthermore, if the residual carbon content of the 10% residue of the fatty acid alkyl ester is within the above range, it becomes easier to enjoy tax benefits.

[0037] (Fatty acids and alkyl alcohols) Fatty acid alkyl esters are broadly defined as esters of fatty acids and alkyl alcohols, and the fatty acid alkyl esters used in this embodiment are esters of fatty acids having 8 to 22 carbon atoms and alkyl alcohols having 1 to 4 carbon atoms, and the above (a １ ) ~ (a ３) all of the following conditions are satisfied.

[0038] As for the fatty acids, either saturated or unsaturated fatty acids can be used. Among fatty acids with 8 to 22 carbon atoms, typical and preferred saturated fatty acids include caprylic acid, pelargonic acid, capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, palmitoleic acid, margaric acid, stearic acid, nonadecylic acid, arachidic acid, henicosyl acid, and behenic acid.

[0039] Furthermore, as unsaturated fatty acids, monounsaturated fatty acids such as myristoleic acid, palmitoleic acid, oleic acid, eicosenoic acid, and erucic acid; and polyunsaturated fatty acids such as linoleic acid, linolenic acid, stearidonic acid, eicosadienoic acid, meadic acid, arachidonic acid, eicosapentaenoic acid, docosadenoic acid, docosapentaenoic acid, and docosahexaenoic acid are typically preferred.

[0040] The fatty acid may be one type or a mixed fatty acid containing two or more types, and the fatty acid alkyl ester is as described above (a １ ) ~ (a ３ ), and furthermore, see below (a ４ ) ~ (a １１ To make it easier to satisfy all of the above conditions and to improve combustion performance and storage stability, it is preferable to use a mixed fatty acid containing two or more types. That is, as described later, it is preferable to use two or more fatty acid alkyl esters using a mixed fatty acid containing two or more types. Furthermore, although the above fatty acids are typically straight-chain fatty acids, the fatty acid can be either a straight-chain fatty acid or a branched-chain fatty acid as long as it has 8 or more carbon atoms and 22 or less.

[0041] Examples of alkyl alcohols having 1 to 4 carbon atoms include methanol, ethanol, propanol, and butanol. Propanol and butanol may have a linear chain or a branched chain. Fatty acid alkyl esters are used as described above (a １ ) ~ (a ３ ), and furthermore, see below (a ４ ) ~ (a １１It is easy to satisfy any of them, and considering improving combustion performance and storage stability performance, and the ease of manufacturing fatty acid alkyl esters, etc., the number of carbon atoms is preferably 3 or less, more preferably 2 or less, that is, more preferably methanol or ethanol, and particularly preferably methanol. Therefore, as the fatty acid alkyl ester used in this embodiment, fatty acid methyl ester is particularly preferable.

[0042] In this embodiment, as the fatty acid alkyl ester, it may be used alone or in combination of two or more. Considering making it easy to satisfy any of the above (a １ ), and improving combustion performance and storage stability performance, it is preferable to use it in combination of two or more. Examples of the combination of two or more include two or more fatty acid alkyl esters formed from two or more fatty acids and one alkyl alcohol, two or more fatty acid alkyl esters formed from one fatty acid and two or more alkyl alcohols, and two or more fatty acid alkyl esters formed from two or more fatty acids and two or more alkyl alcohols, and any of them may be used in this embodiment. ３ ), and further any of the following (a ４ ), and improving combustion performance and storage stability performance, it is preferable to use it in combination of two or more. Examples of the combination of two or more include two or more fatty acid alkyl esters formed from two or more fatty acids and one alkyl alcohol, two or more fatty acid alkyl esters formed from one fatty acid and two or more alkyl alcohols, and two or more fatty acid alkyl esters formed from two or more fatty acids and two or more alkyl alcohols, and any of them may be used in this embodiment. １１ ), and improving combustion performance and storage stability performance, it is preferable to use two or more fatty acid alkyl esters formed from two or more fatty acids and one alkyl alcohol. When using two or more fatty acids, for example, the fatty acids exemplified above may be mixed and used, or a mixed fatty acid containing two or more fatty acids may be used. Examples of the mixed fatty acid preferably include fatty acids obtained from animal oils, vegetable oils, etc. as raw materials. By adopting fatty acids derived from animals and plants obtained from these animal and vegetable oils as raw materials, it is possible to contribute to suppressing global warming by reducing carbon dioxide emissions, and it is extremely useful from the viewpoint of environmental protection.

[0043] Considering making it easy to satisfy any of the above (a １ ), and improving combustion performance and storage stability performance, it is preferable to use two or more fatty acid alkyl esters formed from two or more fatty acids and one alkyl alcohol. When using two or more fatty acids, for example, the fatty acids exemplified above may be mixed and used, or a mixed fatty acid containing two or more fatty acids may be used. Examples of the mixed fatty acid preferably include fatty acids obtained from animal oils, vegetable oils, etc. as raw materials. By adopting fatty acids derived from animals and plants obtained from these animal and vegetable oils as raw materials, it is possible to contribute to suppressing global warming by reducing carbon dioxide emissions, and it is extremely useful from the viewpoint of environmental protection. ３ ), and further any of the following (a ４ ), and improving combustion performance and storage stability performance, it is preferable to use two or more fatty acid alkyl esters formed from two or more fatty acids and one alkyl alcohol. When using two or more fatty acids, for example, the fatty acids exemplified above may be mixed and used, or a mixed fatty acid containing two or more fatty acids may be used. Examples of the mixed fatty acid preferably include fatty acids obtained from animal oils, vegetable oils, etc. as raw materials. By adopting fatty acids derived from animals and plants obtained from these animal and vegetable oils as raw materials, it is possible to contribute to suppressing global warming by reducing carbon dioxide emissions, and it is extremely useful from the viewpoint of environmental protection. １１ ), and improving combustion performance and storage stability performance, it is preferable to use two or more fatty acid alkyl esters formed from two or more fatty acids and one alkyl alcohol. When using two or more fatty acids, for example, the fatty acids exemplified above may be mixed and used, or a mixed fatty acid containing two or more fatty acids may be used. Examples of the mixed fatty acid preferably include fatty acids obtained from animal oils, vegetable oils, etc. as raw materials. By adopting fatty acids derived from animals and plants obtained from these animal and vegetable oils as raw materials, it is possible to contribute to suppressing global warming by reducing carbon dioxide emissions, and it is extremely useful from the viewpoint of environmental protection.

[0044] As animal oils serving as raw materials for mixed fatty acids, typical preferred examples include beef tallow, lard, mutton fat, whale oil, fish oil, cod liver oil, etc. As vegetable oils, typical preferred examples include linseed oil, safflower oil, sunflower oil, soybean oil, corn oil, cottonseed oil, sesame oil, olive oil, castor oil, peanut oil, coconut oil, palm kernel oil, rapeseed oil, rice bran oil, etc. When using natural-derived raw materials such as animal oils and vegetable oils, prior treatment may be carried out as necessary before preparing fatty acid alkyl esters by an esterification reaction with alkyl alcohol. For example, pretreatment by purification such as distillation, clay treatment, etc. can be carried out.

[0045] When using two or more kinds of fatty acids, it is preferable that the two or more kinds of fatty acid alkyl esters contain fatty acid alkyl esters of unsaturated fatty acids having 18 carbon atoms and alkyl alcohol. Among the unsaturated fatty acids having 18 carbon atoms, it is more preferable to contain fatty acid alkyl esters of oleic acid, linoleic acid, and linolenic acid, that is, alkyl oleate, alkyl linoleate, and alkyl linolenate. In this case, the total content of fatty acid alkyl esters of unsaturated fatty acids having 18 carbon atoms and alkyl alcohol contained in the fatty acid alkyl ester is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, even more preferably 75% by mass or more, and particularly preferably 80% by mass or more. Although there is no particular limitation as the upper limit, it is preferably 95% by mass or less. When the total content of fatty acids having 18 carbon atoms is within the above range, it is easy to make the fatty acid alkyl ester satisfy any of the above (a １ ) to (a ３ ), and further any of the following (a ４ ) to (a １１ ), so that the combustion performance and storage stability performance are improved.

[0046] As the raw material for the above mixed fatty acids, vegetable oil is preferred, and rapeseed oil is particularly preferred. Furthermore, as the raw material for the mixed fatty acids, waste cooking oil is preferred, waste cooking oil containing vegetable oil is more preferred, and waste cooking oil containing rapeseed oil is even more preferred. By using waste cooking oil for animal and vegetable oils, competition with food can be avoided, and environmental protection can be achieved through the reuse of waste. As with the above-mentioned naturally derived raw materials such as animal oils and vegetable oils, waste cooking oil may be pretreated as necessary before preparing fatty acid alkyl esters by esterification reaction with alkyl alcohols. For example, pretreatment by refining such as distillation or clay treatment can be performed.

[0047] In this embodiment, when using fatty acids derived from plants or animals as the mixed fatty acids, the mixture may also contain fatty acids other than those with 8 to 22 carbon atoms, i.e., fatty acids with 7 or fewer carbon atoms and 23 or more carbon atoms. In this case, the content of fatty acids with 8 to 22 carbon atoms in the mixed fatty acids is preferably 90% by mass or more, more preferably 92% by mass or more, and even more preferably 95% by mass or more. That is, the content of fatty acids other than those with 8 to 22 carbon atoms is preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 5% by mass or less. The lower limit is preferably as low as possible and there is no particular limit, but it is usually 0.5% by mass or more.

[0048] The fatty acid alkyl ester is the above (a １ ) ~ (a ３ In addition to the properties and composition of the following (a ４ ) ~ (a １１ Preferably, it satisfies at least one property and composition selected from the following (a ４ ) ~ (a １１ It is more preferable that both the properties and composition of the product are satisfied.

[0049] (a ４ The density of the fatty acid alkyl ester at 15°C is preferably 0.8700 g / cm³. ３ The above is a more preferable 0.8750 g / cm³. ３ Above, 0.8800g / cm ３The above applies, with a preferred upper limit of 0.9000 g / cm³. ３ More preferably, 0.8900 g / cm³ ３ More preferably, 0.8850 g / cm³ ３ The following applies: If the density at 15°C is within the above range, the density of the fuel oil composition of this embodiment at 15°C is 0.8950 g / cm³. ３ This makes it easier to achieve the above, resulting in improved combustion performance, fuel efficiency, and storage stability.

[0050] (a ５ The kinematic viscosity of the fatty acid alkyl ester at 50°C is preferably 3,000 mm². ２ / s or more, more preferably 3,200 mm ２ / s or more, more preferably 3,300 mm ２ The value is 1 / s or more, and preferably has an upper limit of 4,500 mm. ２ / s or less, more preferably 4,000 mm ２ / s or less, more preferably 3,900 mm ２ It is less than or equal to / s. If the kinematic viscosity at 50°C is within the above range, the kinematic viscosity of the fuel oil composition of this embodiment at 50°C is 3,000 mm². ２ / s or more 3.500mm ２ This makes it easier to achieve a flow rate of less than / s, improving combustion performance and environmental performance by reducing nitrogen oxide emissions. It also makes it easier to fit various equipment such as pumps and flow meters into the operating range, and improves lubricity.

[0051] (a ６ ) The sulfur content of the fatty acid alkyl ester is preferably 3 ppm by mass or less, and the lower limit is preferable as much as possible, so there is no particular restriction. When the sulfur content is within the above range, it is easier to set the sulfur content of the fuel oil composition of this embodiment to 0.300% by mass or less, so that the occurrence of corrosion can be further suppressed and the environmental performance can be improved. In this specification, the sulfur content of the fatty acid alkyl ester is a value measured in accordance with JIS K 2541-6:2013 (Crude oil and petroleum products - Sulfur content test method - Part 6: Ultraviolet fluorescence method).

[0052] (a ７The flash point of fatty acid alkyl esters is preferably 100.0°C or higher, more preferably 130.0°C or higher, and even more preferably 150.0°C or higher, from the viewpoint of handling safety. There is no particular upper limit, but it is usually 200.0°C or lower. In this specification, the flash point of fatty acid alkyl esters is the value measured in accordance with JIS K 2265-2:2007 (Crude oil and petroleum products - Flash point test method - Part 2: Rapid equilibrium closed method).

[0053] (a ８ The moisture content of the fatty acid alkyl ester is preferably 1,000 mg / kg or less, more preferably 500 mg / kg or less, and even more preferably 250 mg / kg or less. The lower limit is preferably as low as possible and there is no particular limit, but it is usually 100 mg / kg or more. When the moisture content is within the above range, the formation of sludge and the occurrence of freezing are suppressed, and the frequency of clogging can be reduced, thereby improving storage stability. In this specification, the moisture content of the fatty acid alkyl ester is a value measured in accordance with JIS K 2275-2:2015 (Crude oil and petroleum products - Method for determining moisture - Part 2: Karl Fischer volumetric titration method).

[0054] (a ９ The copper plate corrosion of the fatty acid alkyl ester is preferably 1 or less (1a or 1b) in the copper plate classification for copper plate evaluation, and more preferably 1a. If the copper plate corrosion is 1 or less, corrosion of various auxiliary equipment can be prevented, thus enabling more stable operation of various equipment such as internal combustion engines and external combustion engines.

[0055] (a １０ The pour point of the fatty acid alkyl ester is preferably -0.0°C or lower, more preferably -2.5°C or lower, and there is no particular lower limit, but it is usually -20.0°C or higher. When the pour point is within the above range, the fluidity in storage tanks and piping at low temperatures is improved, and handling is also improved.

[0056] (a １１The compositional analysis of fatty acid alkyl esters can be performed by gas chromatography analysis using a flame ionization detector (FID) in accordance with the Standard Method for Analysis of Fats and Oils (established by the Japan Oil Chemists' Society in 1993), "2.4.21.3-77 Fatty Acid Composition (FID Temperature-Increased Gas Chromatography Method)".

[0057] As the fatty acid alkyl ester, it is preferable to include a fatty acid alkyl ester of a mixed fatty acid containing at least oleic acid, linoleic acid, and linolenic acid, as described above, and an alkyl alcohol. The total content of the fatty acid alkyl ester of the mixed fatty acid containing at least oleic acid, linoleic acid, and linolenic acid and an alkyl alcohol, based on the total amount of fatty acid alkyl ester, is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 75% by mass or more, and particularly preferably 80% by mass or more, as described above, and there is no particular upper limit, but it is preferable to keep it at 95% by mass or less.

[0058] When the fatty acid alkyl ester contains two or more fatty acid alkyl esters, it is preferable to include at least oleate alkyl ester, linoleate alkyl ester, and linolenic acid alkyl ester (fatty acid alkyl ester of an unsaturated fatty acid with 18 carbon atoms and an alkyl alcohol), as described above. It is even more preferable to include stearate alkyl ester (fatty acid alkyl ester of a saturated fatty acid with 18 carbon atoms and an alkyl alcohol), even more preferable to include palmitate alkyl ester (fatty acid alkyl ester of a saturated fatty acid with 16 carbon atoms and an alkyl alcohol), even more preferable to include arachidinate alkyl ester and erucate alkyl ester (fatty acid alkyl ester of saturated fatty acids with 20 and 22 carbon atoms and an alkyl alcohol), and even more preferable to include eicosenoate alkyl ester and behenate alkyl ester (fatty acid alkyl ester of an unsaturated fatty acid with 20 and 22 carbon atoms and an alkyl alcohol), and it is particularly preferable to include at least one selected from caprylate alkyl ester, caprate alkyl ester, laurate alkyl ester, and myristate alkyl ester.

[0059] (Content of fatty acid alkyl esters) The content of fatty acid alkyl esters on a basis of the total composition is 15.0% by volume or more and 35.0% by volume or less. If the content of fatty acid alkyl esters is less than 15.0% by volume, the combustion performance decreases, and if it exceeds 35.0% by volume, the storage stability performance decreases. From the viewpoint of improving combustion performance and storage stability performance, the content of fatty acid alkyl esters on a basis of the total composition is preferably 17.5% by volume or more, more preferably 20.0% by volume or more, and preferably 32.5% by volume or less as the upper limit.

[0060] (Cracked Light Oil Fraction) The fuel oil composition of this embodiment contains cracked light oil fraction in an amount of more than 40.0% by volume and 60.0% by volume or less on a basis of the total volume of the composition. The cracked light oil fraction is the catalytically cracked light oil fraction obtained by fluid catalytic cracking of atmospheric distillation residue oil and / or vacuum distillation residue oil. The cracked light oil fraction used in this embodiment is, among the above fractions, the following (b １ ) ~ (b ４ (b) It satisfies the properties and composition of ). １ ) The kinematic viscosity at 50°C is 2,600 mm ２ / s or more 3.600mm ２ / s or less (b ２ ) Sulfur content is 0.400% by mass or less (b ３ ) Aromatic content of 50.0% by volume or more (b ４ ) Aromatic content of three or more rings is 10.0% by volume or more.

[0061] (b １ The kinematic viscosity of the cracked diesel fraction at 50°C is 2,600 mm². ２ / s or more 3.600mm ２ It is less than or equal to / s. If the kinematic viscosity at 50°C is not within the above range, the kinematic viscosity of the fuel oil composition of this embodiment at 50°C will be 3,000 mm². ２ / s or more 3.500mm ２Since it becomes difficult to keep the kinematic viscosity below / s, combustion performance and environmental performance in reducing nitrogen oxide emissions may decrease, it may become difficult to adapt to the operating range of various equipment such as pumps and flow meters, and lubricity may decrease. From the viewpoint of improving combustion performance and environmental performance, adapting to the operating range of various equipment, and improving lubricity, by making it easier to keep the kinematic viscosity of the fuel oil composition of this embodiment at 50°C within the above range, it is preferably 2,800 mm. ２ / s or more, more preferably 2,900 mm ２ / s or more, more preferably 2,950 mm ２ The value is 1 / s or more, and preferably has an upper limit of 3,400 mm. ２ / s or less, more preferably 3,300 mm ２ / s or less, more preferably 3,200 mm ２ It is less than or equal to / s.

[0062] (b ２ ) Sulfur content The sulfur content of the cracked diesel fraction is 0.400% by mass or less. If the sulfur content is not within the above range, it becomes difficult to keep the sulfur content of the fuel oil composition of this embodiment at 0.300% by mass or less, which can make it difficult to suppress corrosion and may reduce environmental performance. Considering that it is possible to suppress corrosion and improve environmental performance by making it easier to keep the sulfur content of the fuel oil composition of this embodiment at 0.300% by mass or less, the sulfur content of the cracked diesel fraction is preferably 0.300% by mass or less, more preferably 0.280% by mass or less, and the lower limit is preferably as low as possible, with no particular restrictions, but it is usually 0.05% by mass or more.

[0063] (b ３The aromatic content of the cracked diesel fraction is 50.0% by volume or more. Here, the aromatic content refers to the total content of mono-ring aromatics, di-ring aromatics, and three-ring or more aromatics. If the aromatic content is not within the above range, it may not be possible to suppress the blockage of the fuel oil filter due to sludge generation, which may reduce normal fuel flow performance and combustion performance. From the viewpoint of improving normal fuel flow performance and combustion performance by further suppressing the blockage of the fuel oil filter due to sludge generation, it is preferably 60.0% by volume or more, more preferably 65.0% by volume or more, and there is no particular upper limit, but it is usually 85.0% by volume or less.

[0064] (b ４ ) Content of aromatic compounds with three or more rings The content of aromatic compounds with three or more rings in the cracked diesel fraction is 10.0% by volume or more. If the content of aromatic compounds with three or more rings is not within the above range, it becomes difficult to make the content of aromatic compounds with three or more rings in the fuel oil composition of this embodiment 6.0% by volume or more, which may reduce storage stability. From the viewpoint of making it easier to make the content of aromatic compounds with three or more rings in the fuel oil composition of this embodiment 6.0% by volume or more and improving storage stability, it is preferably 11.0% by volume or more, more preferably 11.5% by volume or more, and even more preferably 12.0% by volume or more, with no particular upper limit, and is usually 18.0% by volume or less.

[0065] The cracked diesel fraction is as described above (b １ ) ~ (b ４ In addition to the properties and composition of the following (b ５ ) ~ (b １４ Preferably, it satisfies at least one selected from the properties and composition of the following (b ５ ) ~ (b １４ It is more preferable that both the properties and composition of the product are satisfied.

[0066] (b ５ The density of the light oil fraction at 15°C is preferably 0.9100 g / cm³. ３ More preferably, 0.9200 g / cm³ ３ More preferably 0.925 g / cm³ ３The above applies, with a preferred upper limit of 0.9500 g / cm³. ３ More preferably, 0.9400 g / cm³ ３ The following applies: If the density at 15°C is within the above range, the density of the fuel oil composition of this embodiment at 15°C is 0.8950 g / cm³. ３ This makes it easier to achieve the above, resulting in improved combustion performance, fuel efficiency, and storage stability.

[0067] (b ６ The flash point of the light oil fraction that undergoes flash point decomposition is preferably 60.0°C or higher, more preferably 65.0°C or higher, and even more preferably 70.0°C or higher, from the viewpoint of improving handling safety. There is no particular upper limit on the flash point, and it is usually 100°C or lower.

[0068] (b ７ ) Residual carbon content of 10% residual oil The residual carbon content of the 10% residual oil of the decomposed diesel fraction is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and preferably 0.20% by mass or less as an upper limit. When the residual carbon content of the 10% residual oil is within the above range, it becomes easier to set the residual carbon content of the 10% residual oil of the fuel oil composition of this embodiment to 0.21% by mass or more and 0.60% by mass or less, thereby improving combustion performance and storage stability performance. It also becomes easier to enjoy tax benefits.

[0069] (b ８ The cetane number of the cetane-cracked diesel fraction is preferably 20.0 or higher, more preferably 21.0 or higher, with no particular upper limit, and is usually 45.0 or lower. When the cetane number is within the above range, it becomes easier to make the cetane number of the fuel oil composition of this embodiment 31.0 or higher, thereby improving combustion performance.

[0070] (b ９ The moisture content of the decomposed diesel fuel fraction is preferably 0.10% by volume or less, more preferably less than 0.10% by volume. There is no particular lower limit, as a smaller limit is preferable. When the moisture content is within the above range, the formation of sludge and the occurrence of ice formation can be suppressed, and the frequency of blockage can be reduced, thereby improving storage stability.

[0071] (b １０) The copper plate corrosion of the light oil fraction in the copper plate corrosion decomposition is preferably 1 or less (1a or 1b) in the classification of the copper plate in the copper plate determination, and more preferably 1a. If the copper plate corrosion is 1 or less, corrosion of various auxiliary equipment can be prevented, thereby enabling more stable operation of various equipment such as internal combustion engines and external combustion engines.

[0072] (b １１ The acid value of the acid-decomposed diesel fraction is preferably 0.10 mg KOH / g or less, and more preferably less than 0.10 mg KOH / g. The lower the acid value, the better, and there is no particular lower limit, but it is particularly preferably 0.0 mg KOH / g. When the acid value is within the above range, storage stability is improved and corrosion of components can be suppressed.

[0073] (b １２ The pour point of the pour point cracked diesel fraction is preferably -5.0°C or lower, more preferably -7.5°C or lower. There is no particular lower limit, but it is usually -35.0°C or higher. When the pour point is within the above range, fluidity in storage tanks and piping at low temperatures is improved, and handling is also improved.

[0074] (b １３ ) Nitrogen content The nitrogen content of the cracked diesel fraction is preferably 500 ppm by mass or less, more preferably 400 ppm by mass or less, and even more preferably 300 ppm by mass or less. There is no particular lower limit, but it is usually 50 ppm by mass or more. When the nitrogen content is within the above range, nitrogen oxides (NO) are produced. Ｘ This reduces emissions, thus improving environmental performance.

[0075] (b １４) Distillation properties As for the distillation properties of the cracked light oil fraction, the 10% by volume distillation temperature is preferably 190.0°C or higher, more preferably 200.0°C or higher, even more preferably 225.0°C or higher, with an upper limit of preferably 250.0°C or lower, more preferably 245.0°C or lower. The 50% by volume distillation temperature is preferably 250.0°C or higher, more preferably 260.0°C or higher, even more preferably 270.0°C or higher, with an upper limit of preferably 310.0°C or lower, more preferably 300.0°C or lower, even more preferably 285.0°C or lower. Also, the 90% by volume distillation temperature is preferably 310.0°C or higher, more preferably 320.0°C or higher, even more preferably 330.0°C or higher, with an upper limit of preferably 370.0°C or lower, more preferably 360.0°C or lower, even more preferably 350.0°C or lower. When the distillation properties of the cracked diesel fraction are such that the distillation temperatures are 10% by volume, 50% by volume, and 90% by volume, the effects of low-boiling-point and high-boiling-point components are suppressed, and combustion performance is improved. In this specification, the 10% by volume, 50% by volume, and 90% by volume distillation temperatures of the distillation properties are values ​​measured in accordance with JIS K2254:2018 (Petroleum products - Method for determining distillation properties - (Atmospheric pressure method)).

[0076] (Content of cracked diesel fraction) The content of cracked diesel fraction on a basis of the total composition is greater than 40.0% by volume and 60.0% by volume or less. If the content of cracked diesel fraction is 40.0% by volume or less, fuel efficiency and storage stability will decrease, and if it exceeds 60.0% by volume, combustion performance will decrease. From the viewpoint of improving combustion performance, fuel efficiency, and storage stability, the content of cracked diesel fraction on a basis of the total composition is preferably 42.5% by volume or more, more preferably 45.0% by volume or more, and as an upper limit, preferably 57.5% by volume or less, more preferably 55.0% by volume or less.

[0077] (Other light oil and kerosene fractions) In addition to the cracked light oil fraction described above, the fuel oil composition of this embodiment may also contain the following light oil fractions, such as straight-run light oil fraction, straight-run light oil fraction, vacuum-pressure light oil fraction, desulfurized light oil fraction, and desulfurized cracked light oil fraction, as well as kerosene fractions, such as straight-run kerosene fraction and desulfurized kerosene fraction. Among these light oil and kerosene fractions, the straight-run light oil fraction is preferred from the viewpoint of improving fuel efficiency, combustion performance, environmental performance by reducing nitrogen oxide emissions, and storage stability when combined with fatty acid alkyl esters and cracked light oil fractions. These light oil and kerosene fractions can be used individually or in combination of multiple types. - Direct desulfurization of diesel fraction (diesel fraction obtained by directly desulfurizing atmospheric distillation residue oil and / or vacuum distillation residue oil in a desulfurization unit) - Straight-run diesel fraction (diesel fraction obtained by atmospheric distillation of crude oil in an atmospheric distillation unit) - Vacuum-reduced diesel fraction (diesel fraction obtained by vacuum distillation of atmospheric distillation residue oil in a vacuum distillation unit) - Desulfurization of diesel fraction (diesel fraction obtained by desulfurizing straight-run diesel fraction and / or vacuum-reduced diesel fraction) - Desulfurization cracked diesel fraction (diesel fraction obtained by desulfurizing catalytically cracked diesel fraction obtained by fluid catalytic cracking of atmospheric distillation residue oil and / or vacuum distillation residue oil) - Straight-run kerosene fraction (kerosene fraction obtained by atmospheric distillation of crude oil in an atmospheric distillation unit) - Desulfurization of kerosene fraction (kerosene fraction obtained by desulfurizing straight-run kerosene fraction)

[0078] (Properties of other diesel and kerosene fractions) The other diesel and kerosene fractions that can be used in this embodiment preferably have the following properties. When the other diesel and kerosene fractions have the following properties, in combination with fatty acid alkyl esters and cracked diesel fractions, fuel efficiency and combustion performance, environmental performance that reduces nitrogen oxide emissions, and storage stability can be improved.

[0079] The kinematic viscosity at 50°C is preferably 3,100 mmHg. ２ / s or more, more preferably 3,800 mm ２ / s or more, preferably with an upper limit of 5,000 mm ２ / s or less, more preferably 4,500 mm ２The saturation is less than or equal to / s. The sulfur content is preferably 1,000% by mass or less, more preferably 0,400% by mass or less, and even more preferably 0,100% by mass or less, with the lower limit being as low as possible, usually 0.010% by mass or more. The aromatic content is preferably 30.0% by volume or more, more preferably 35.0% by volume or more, and more preferably 40.0% by volume or more, with no particular upper limit, usually 65.0% by volume or less. The aromatic content of three or more rings is preferably 1.5% by volume or more, more preferably 1.8% by volume or more, with no particular upper limit, usually 5.0% by volume or less. The density at 15°C is preferably 0.8300 g / cm³ ３ More preferably 0.8400 g / cm³ ３ More preferably, 0.8500 g / cm³ ３ The above is true, with a preferred upper limit of 0.8900 g / cm³. ３ More preferably, 0.8800 g / cm³ ３The following are the requirements: The flash point is preferably 60.0°C or higher, more preferably 65.0°C or higher. The residual carbon content of the 10% residual oil is preferably 0.01% by mass or higher, with an upper limit of preferably 0.20% by mass or lower. The cetane number is preferably 30.0 or higher, more preferably 35.0 or higher, with no particular upper limit, and is usually 70.0 or lower. The moisture content is preferably 0.10% by volume or lower, more preferably less than 0.10% by volume. The copper plate corrosion is preferably 1 or lower (1a or 1b) in the classification of the copper plate in the copper plate determination, and is especially preferably 1a. The acid value is preferably 0.05 mg KOH / g or lower, more preferably less than 0.05 mg KOH / g. The lower the acid value, the better, with no particular lower limit, and is especially preferably 0.0 mg KOH / g. The pour point is preferably -0.0°C or lower, more preferably -2.5°C or lower, with no particular lower limit, but usually -30.0°C or higher. The nitrogen content is preferably 500 ppm by mass or less, more preferably 300 ppm by mass or less, with no particular lower limit, but usually 50 ppm by mass or higher. As for the distillation properties, the 10% by volume distillation temperature is preferably 170.0°C or higher, more preferably 180.0°C or higher, with an upper limit of preferably 270.0°C or lower, more preferably 260.0°C or lower. The 50% by volume distillation temperature is preferably 250.0°C or higher, more preferably 265.0°C or higher, with an upper limit of preferably 310.0°C or lower, more preferably 300.0°C or lower. Also, the 90% by volume distillation temperature is preferably 310.0°C or higher, more preferably 330.0°C or higher, with an upper limit of preferably 370.0°C or lower, more preferably 355.0°C or lower.

[0080] (Content of other diesel and kerosene fractions) The content of other diesel and kerosene fractions on a basis of the total composition is preferably 5.0% by volume or more, more preferably 10.0% by volume or more, and even more preferably 12.5% ​​by volume or more, with an upper limit of preferably 45.0% by volume or less, more preferably 40.0% by volume or less, and even more preferably 35.0% by volume or less.

[0081] (Other heavy oil fractions, etc. (residual carbon sources)) In addition to the cracked light oil fraction described above, the fuel oil composition of this embodiment may also contain the following heavy oil fractions, such as atmospheric distillation residue oil, vacuum distillation residue oil, direct dewatering heavy oil and cracked heavy oil, as well as heavy oil fractions such as extract (the above fractions, etc. are also referred to as "residual carbon sources"). Among these heavy oil fractions, etc. (residual carbon sources), atmospheric distillation residue oil is preferred from the viewpoint of improving fuel efficiency, combustion performance, environmental performance by reducing nitrogen oxide emissions, and storage stability when combined with fatty acid alkyl esters and cracked light oil fractions. These heavy oil fractions, etc. (residual carbon sources) can be used individually or in combination of multiple types. - Atmospheric distillation residue oil (residual oil obtained by atmospheric distillation of crude oil in an atmospheric distillation unit) - Vacuum distillation residue oil (residual oil obtained by vacuum distillation of atmospheric distillation residue oil in a vacuum distillation unit) - Direct desulfurization heavy oil fraction (heavy oil obtained by directly desulfurizing atmospheric distillation residue oil and / or vacuum distillation residue oil in a desulfurization unit) - Cracking heavy oil fraction (heavy oil obtained by fluid catalytic cracking of direct desulfurization heavy oil) - Extract (highly aromatic oil obtained by distilling and separating medium and heavy vacuum distillation distillates obtained by vacuum distillation of atmospheric distillation residue oil, and dehisced oil (bright stock oil) of vacuum distillation residue oil with furfural, etc.)

[0082] (Properties of other heavy oil fractions, etc. (residual carbon sources)) The density at 15°C is preferably 0.9850 g / cm³ ３ More preferably, 0.9750 g / cm³ ３ Below, 0.9600g / cm ３ The following limits are observed, with a preferred lower limit of 0.9100 g / cm³. ３More preferably, 0.9300 g / cm³ ３ That concludes the report. The kinematic viscosity at 50°C is preferably 200.000 mm². ２ / s or less, more preferably 190,000 mm ２ It is less than or equal to / s, and there is no particular lower limit, usually 30,000 mm. ２ The ratio is 1 / s or more. The sulfur content is preferably 3,000% by mass or less, more preferably 2,750% by mass or less, and there is no particular limit as the lower limit is preferable as long as it is as small as possible, and it is usually 0,500% by mass or more. The residual carbon content of the 10% residual oil is preferably 25.0% by mass or more, more preferably 40.0% by mass or more, even more preferably 45.0% by mass or more, and the upper limit is preferably 100.0% by mass or less, more preferably 70.0% by mass or less. The moisture content is preferably 0.1% by volume or less, more preferably less than 0.1% by volume. Copper plate corrosion is preferably 1 or less (1a or 1b) as a classification of the copper plate in the determination of the copper plate, and more preferably 1a. The residual carbon content is preferably 3.0% by mass or more, more preferably 5.0% by mass or more, and the upper limit is preferably 12.0% by mass or less, more preferably 9.0% by mass or less. In this specification, the residual carbon content is the value measured in accordance with JIS K 2270-2:2009 (Crude oil and petroleum products - Method for determining residual carbon content - Part 2: Microscopic method).

[0083] (Content of other heavy oil fractions, etc. (residual carbon sources)) The content of other heavy oil fractions, etc. (residual carbon sources) on a basis of the total composition is preferably 0.01% by volume or more, more preferably 0.10% by volume or more, even more preferably 0.15% by volume or more, with an upper limit of preferably 1.00% by volume or less, more preferably 0.50% by volume or less, and even more preferably 0.30% by volume or less.

[0084] (Various Additives) The fuel oil composition of this embodiment may contain various additives as needed, such as antioxidants, low-temperature fluidity improvers, lubricity improvers, cetane number improvers, combustion accelerators, detergents, sludge dispersants, and antifungal agents, selected as appropriate, within the limits that can maintain the above-mentioned properties. Coumarin may also be added from the standpoint of light oil excise tax.

[0085] (Applications) The fuel oil composition of this embodiment is excellent in fuel efficiency and combustion performance, as well as in environmental performance that reduces nitrogen oxide emissions, and also in storage stability, making it suitable for use in both internal and external combustion engines. Considering that it exhibits excellent performance in the combustion performance evaluation method using a hydraulic spray burner, it is more preferable to use it in an external combustion engine, and among those, it is more preferable to use it in an external combustion engine equipped with a hydraulic spray burner, and even more preferable to use it in an external combustion engine equipped with a hydraulic spray burner with a rated fuel amount of 100 L / hour or less.

[0086] [Method for producing the fuel oil composition] The fuel oil composition of this embodiment can be produced by mixing the above-mentioned fatty acid alkyl ester and cracked light oil fraction, and optionally the above-mentioned other light oil fraction, kerosene fraction, heavy oil fraction, etc. (residual carbon source) and various additives, such that the content of fatty acid alkyl ester and cracked light oil fraction on a basis of the total composition is 15.0% by volume or more and 35.0% by volume or less, and more than 40.0% by volume and 60.0% by volume or less, respectively.

[0087] There are no particular restrictions on the order in which fatty acid alkyl esters and cracked light oil fractions, and optionally other light oil fractions, kerosene fractions, heavy oil fractions, etc. (residual carbon sources), and various additives are blended. For example, fatty acid alkyl esters may be mixed with cracked light oil fractions, and optionally other light oil fractions, heavy oil fractions, etc. (residual carbon sources), and various additives in succession. Alternatively, fatty acid alkyl esters, cracked light oil fractions, and optionally other light oil fractions, heavy oil fractions, etc. (residual carbon sources), and various additives may be mixed simultaneously (all-at-once mixing). Alternatively, fatty acid alkyl esters and cracked light oil fractions may be mixed beforehand, and then optionally other light oil fractions, heavy oil fractions, etc. (residual carbon sources) and various additives may be mixed. Alternatively, fatty acid alkyl esters and cracked light oil fractions may be mixed beforehand, and then optionally other light oil fractions, heavy oil fractions, etc. (residual carbon sources) and various additives may be added and mixed in any order.

[0088] Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited in any way by these examples. The properties of each substrate were determined according to the method described above.

[0089] [Measurement of Properties and Composition] The properties and composition of the various base materials used in the Examples and Comparative Examples, including fatty acid alkyl esters, cracked light oil fractions, direct decontaminated light oil fractions, and atmospheric distillation residue oil, as well as the properties and composition of the fuel oil compositions in the Examples and Comparative Examples, were measured by the following methods. The properties and composition of the fatty acid alkyl esters are shown in Table 1, and the properties and composition of the other various base materials are shown in Table 2. The properties and composition of the fuel oil compositions are shown in Tables 3 to 6. ・(1) (a ４ ) ( b ５ ) Density at 15°C: Measured in accordance with JIS K 2249-1:2011 (Crude oil and petroleum products - Method for determining density - Part 1: Vibration method). ・(2) (a ５ ) ( b １ ) Kinematic viscosity at 50°C: Measured in accordance with JIS K 2283:2000 (Test method for kinematic viscosity of crude oil and petroleum products). ・(3) (a ６ ) ( b ２) Sulfur content: The sulfur content of fuel oil composition, cracked diesel fraction, direct decontaminated diesel fraction, and atmospheric distillation residue oil is measured in accordance with JIS K 2541-4:2003 (Crude oil and petroleum products - Sulfur content test method - Part 4: Radiation excitation method), and the sulfur content of fatty acid alkyl esters is measured in accordance with JIS K 2541-6:2013 (Crude oil and petroleum products - Sulfur content test method - Part 6: Ultraviolet fluorescence method). ・(4)(b ３ ) ( b ４ ) Aromatic content (mono-ring aromatics, bi-ring aromatics, and tri-ring or more aromatics): Measured by High Performance Liquid Chromatography, as specified in JPI-5S-49-2007, Petroleum Products - Hydrocarbon Type Test Method. ・(5)(a ３ ) ( b ７ ) Residual carbon content of 10% residual oil: This value is measured using 10% residual oil prepared in accordance with Annex A, in accordance with JIS K 2270-2:2009 (Crude oil and petroleum products - Method for determining residual carbon content - Part 2: Microscopic method). The residual carbon content is also measured in accordance with JIS K 2270-2:2009 (Crude oil and petroleum products - Method for determining residual carbon content - Part 2: Microscopic method). ・(6)(a １ ) ( b ８ ) Cetane number: This is a value measured in accordance with JIS K 2280-4:2013 (Petroleum products - Method for determining octane number, cetane number and cetane index - Part 4: Cetane number). ・(7) (a ７ ) ( b ６ ) Flash point: The flash points of fuel oil compositions, cracked diesel fractions, direct decontaminated diesel fractions, and atmospheric distillation residue oils were measured in accordance with JIS K 2265-3:2007 (Crude oil and petroleum products - Flash point test methods - Part 3: Pennsky-Haltens closed method), and the flash points of fatty acid alkyl esters were measured in accordance with JIS K 2265-2:2007 (Crude oil and petroleum products - Flash point test methods - Part 2: Rapid equilibrium closed method). ・(8)(a ８ ) ( b ９) Moisture content: The moisture content of fuel oil composition, cracked light oil fraction, direct decontaminated light oil fraction, and atmospheric distillation residue oil was measured in accordance with JIS K 2275-1:2015 (Crude oil and petroleum products - Method for determining moisture content - Part 1: Distillation method), and the moisture content of fatty acid alkyl esters was measured in accordance with JIS K 2275-3:2015 (Crude oil and petroleum products - Method for determining moisture content - Part 3: Karl Fischer coulometric titration method). ・(9)(a ９ ) ( b １０ ) Copper plate corrosion: Measured in accordance with JIS K 2513:2000 (Petroleum products - Copper plate corrosion test method -). The test temperature was 50°C and the test time was 3 hours. ・(10)(a ２ ) ( b １１ ) Acid value: Measured in accordance with JIS K 2501:2003 (Petroleum products and lubricating oils - Neutralization value test method). ・(11)(a １０ ) ( b １２ ) Pour point: Measured in accordance with JIS K2269:1987 (Test method for pour point and cloud point of crude oil and petroleum products). ・(12)(b) １３ ) Nitrogen content: Measured in accordance with JIS K 2609:1998 (Crude oil and petroleum products - Nitrogen content test method). ・(13) Total calorific value: Measured based on the method described in "1. Fuel efficiency performance" below. ・(a １１ ) Composition analysis of fatty acid alkyl esters: Measured by gas chromatography analysis using a flame ionization detector (FID) in accordance with the Standard Method for Analysis of Fats and Oils (established by the Japan Oil Chemists' Society in 1993) "2.4.21.3-77 Fatty Acid Composition (FID Temperature-Increased Gas Chromatography Method)". ・(b １４ Distillation properties (at 10% volume distillation temperature, 50% volume distillation temperature, and 90% volume distillation temperature): Measured in accordance with JIS K2254:2018 (Petroleum products - Method for determining distillation properties - (atmospheric pressure method)).

[0090] [Performance Evaluation Criteria] Each of the following performance aspects (1-4) was evaluated, and the worst evaluation was used as the overall evaluation. A C rating indicates failure. The evaluations for each performance aspect are shown in Tables 3 and 4.

[0091] 1. For the fuel oil compositions of the fuel efficiency examples and comparative examples, the "Gross heat of combustion," measured according to the test method specified in "Standard Test Method for Heat of Combustion of Liquid Hydrocarbon Fuels by Bomb Calorimeter" (ASTM D240-9), was multiplied by the density to convert the value to a per-volume value, and evaluated according to the following criteria as the total calorific value (MJ / L): A: 38.9 MJ / L or higher. B: 38.7 MJ / L or higher and less than 38.9 MJ / L. C: Less than 38.7 MJ / L.

[0092] 2. Combustion Performance The fuel oil compositions of the examples and comparative examples were evaluated as follows: (1) Test machine and setting conditions A "House Kaonki HK2027TCV1 (model)" (rated fuel amount: 6.3 L / h, on / off control, manufactured by Nepon Corporation) was used as the test machine. ・Fuel spray pressure: 1.03 MPa (hydraulic spray burner) ・Band shutter opening: Adjusted so that the oxygen concentration in the exhaust gas is 2.8 ± 0.2% ・Fuel heating burner front heater: Off ・Evaluation room temperature: 29 to 34°C ・Sample oil temperature: 25 to 30°C (2) Evaluation items After 20 minutes of continuous combustion under the same conditions, the following items were evaluated. (Ignition) No visual delay in ignition occurred during ignition. (Combustibility; measurement of soot concentration) An exhaust gas sampling hole was attached to the flue closest to the boiler body (the combustion chamber portion of the "House Kaonki" mentioned above), and the soot concentration (Bakkalacca smoke number (SN)) in the combustion exhaust gas was measured using a Bakkalacca smoke tester based on the test method specified in "Standard Test Method for Smoke Density in Fuel Gases from Burning Distillate Fuels" (ASTM D2156-09). (3) Evaluation criteria The evaluation items in (2) above were evaluated according to the following criteria. A: There was no ignition delay, and the soot concentration (SN) was 1.0 or less. B: There was no ignition delay, and the soot concentration (SN) was greater than 1.0 and less than or equal to 2.0. C: The result was different from A and B above.

[0093] 3. Environmental performance (nitrogen oxides (NOx)Ｘ (Reduction performance) (1) Test machine and setting conditions The same as in "2. Combustion performance" (1) above. (2) Evaluation items At the same time as the evaluation items in "2. Combustion performance" (2) above (combustibility; measurement of soot concentration), the oxygen concentration and nitrogen oxides (NOx) in the combustion exhaust gas were measured. Ｘ The concentration of nitrogen oxides (NOx) was measured using a combustion exhaust gas analyzer ("HT-1300Z (model number)", manufactured by Hodaka Co., Ltd.). Based on the measured results, the value converted to an oxygen concentration of 0% using the following formula was used to determine the nitrogen oxide (NOx) concentration. Ｘ The concentration was defined as ) . Nitrogen oxide concentration (volume ppm) = C ＮＯｘ (capacity ppm) x 21 / (21-C Ｏ ) C ＮＯｘ : Nitrogen oxides (NO Ｘ ) Concentration measurement value (volume ppm) C Ｏ : Oxygen concentration measurement value (volume %) (3) Evaluation criteria The evaluation items in (2) above were evaluated according to the following criteria: A: Nitrogen oxide concentration was 80 volume ppm or less. B: Nitrogen oxide concentration was greater than 80 volume ppm and 90 volume ppm or less. C: Nitrogen oxide concentration was greater than 90 volume ppm.

[0094] 4. Storage Stability Performance 1 liter each of the fuel oil compositions of the examples and comparative examples was placed in a 4 liter tin can (made of tin) with an opening (φ32.5 mm) at the top to allow air circulation, and stored in a dark place at room temperature for 90 days (no temperature control by air conditioning was performed, and the room temperature during the period was 20-32°C). The amount of dry sludge contained in the fuel oil composition after storage was measured according to the Japan Fisheries Cooperative Association's dry sludge measurement method (All Japan Fisheries Cooperative Association ZGS T-1010). The amount of dry sludge was evaluated according to the following criteria: A: The amount of dry sludge was 1.0 mg / 100 mL or less B: The amount of dry sludge was greater than 1.0 mg / 100 mL and 2.0 mg / 100 mL or less C: The amount of dry sludge was greater than 2.0 mg / 100 mL

[0095] [Examples 1-4 and Comparative Examples 1-14] Various base materials having the properties and compositions shown in Tables 1 and 2 were mixed in the proportions shown in Tables 3-6 to prepare fuel oil compositions for Examples 1-4 and Comparative Examples 1-14. For each of the obtained fuel oil compositions, the combustion performance and storage stability performance were evaluated using the method described above. The results are shown in Tables 3-6.

[0096] *1. Both base material 1 (fatty acid alkyl ester 1) and base material 2 (fatty acid alkyl ester 2) are fatty acid methyl esters obtained using waste cooking oil containing rapeseed oil.

[0097]

[0098]

[0099]

[0100]

[0101]

[0102] [Performance Evaluation Results] As shown in Table 3, the fuel oil composition of this embodiment was found to be suitable for internal and external combustion engines, as it exhibited good fuel efficiency, combustion performance, environmental performance, and storage stability. Furthermore, due to its excellent combustion performance with hydraulic spray burners, it was found to be particularly suitable for external combustion engines equipped with hydraulic spray burners, especially those with a rated combustion volume of 100 L / hour or less. External combustion engines equipped with hydraulic spray burners have nitrogen oxides (NOx) in their combustion exhaust gases. Ｘ Installing denitrification equipment to reduce nitrogen oxides (NOx) is difficult from a cost standpoint. The fuel oil composition of this embodiment is nitrogen oxide (NOx) ＸConsidering its excellent environmental performance in reducing emissions of nitrogen oxides (NOx), it can be particularly suitable for use in external combustion engines equipped with the above-mentioned hydraulic spray burner. Furthermore, the sulfur content in the fuel oil composition of this embodiment is 0.140 to 0.160 mass%, which is extremely low at 0.300 mass% or less, making it possible to prevent corrosion caused by an increase in sulfur oxides in the exhaust gas and to prevent an increase in the environmental burden. Therefore, the fuel oil composition of this embodiment is suitable for use in external combustion engines equipped with the above-mentioned hydraulic spray burner. Ｘ It was confirmed that this product has extremely excellent environmental performance, as it can reduce not only emissions of ) but also emissions of sulfur oxides.

[0103] On the other hand, the fuel oil compositions of Comparative Examples 1 and 2, which contained a small amount of the specific fatty acid alkyl ester 1, were inferior in terms of combustion performance, and the fuel oil composition of Comparative Example 3, which contained a large amount, was inferior in terms of storage stability performance. The fuel oil compositions of Comparative Examples 4 and 5, which did not contain the specific fatty acid alkyl ester 1 but contained fatty acid alkyl ester 2 with a low residual carbon content in the 10% residual oil, were both found to be inferior in terms of storage stability performance. Regarding the cracked diesel fraction, the fuel oil compositions of Comparative Examples 6, 8-10, which reduced the content of the cracked diesel fraction and increased the direct-release diesel fraction, were found to be inferior in terms of fuel efficiency performance and storage stability performance, and the fuel oil composition of Comparative Example 7, which contained a large amount, was found to be inferior in terms of combustion performance. Furthermore, the fuel oil compositions of Comparative Examples 11-14, which reduced the content of the cracked diesel fraction and increased the cracked diesel fraction with low kinematic viscosity, were found to be inferior in terms of environmental performance.

[0104] The fuel oil composition of this embodiment contains fatty acid alkyl esters and cracked light oil fractions in predetermined amounts, resulting in a composition that is excellent in fuel efficiency and combustion performance, as well as environmental performance that reduces nitrogen oxide emissions, and also has excellent storage stability. It can be suitably used in internal combustion engines and external combustion engines, especially external combustion engines equipped with hydraulic spray burners.

Claims

1. A fuel oil composition satisfying all of the following (a １ ), (a ３ ), which comprises a fatty acid alkyl ester satisfying all of the following (b １ ), (b ４ ), and a cracked light oil fraction. The fatty acid alkyl ester is an ester of a fatty acid having 8 to 22 carbon atoms and an alkyl alcohol having 1 to 4 carbon atoms. The content of the fatty acid alkyl ester based on the total amount of the composition is 15.0% by volume or more and 35.0% by volume or less, and the content of the cracked light oil fraction based on the total amount of the composition is more than 40.0% by volume and 60.0% by volume or less. (a １ ) The cetane number is 49.0 or more. (a ２ ) The acid value is 0.50 mg KOH / g or less. (a ３ ) The residual carbon content of the 10% residual oil is 0.80% by mass or more and 1.50% by mass or less. (b １ ) The kinematic viscosity at 50 °C is 2.600 mm ２ / s or more and 3.600 mm ２ / s or less. (b ２ ) The sulfur content is 0.400% by mass or less. (b ３ ) The aromatic content is 50.0% by volume or more. (b ４ ) The content of aromatic components with 3 or more rings is 10.0% by volume or more. (1) The density at 15 °C is 0.8950 g / cm ３ or more. (2) The kinematic viscosity at 50 °C is 3.000 mm ２ / s or more and 3.500 mm ２ / s or less. (3) The sulfur content is 0.300% by mass or less. (4) The content of aromatic components with 3 or more rings is 6.0% by volume or more. (5) The residual carbon content of the 10% residual oil is 0.21% by mass or more and 0.60% by mass or less. (6) The cetane number is 31.0 or more.

2. The fuel oil composition according to claim 1, wherein the fatty acid alkyl ester is a fatty acid methyl ester.

3. The fuel oil composition according to claim 1 or 2, wherein the fatty acid is a mixed fatty acid containing two or more fatty acids having 8 or more carbon atoms and 22 or fewer carbon atoms.

4. The fuel oil composition according to claim 3, wherein the mixed fatty acid is obtained from at least one raw material selected from animal oils and vegetable oils.

5. The fuel oil composition according to claim 1 or 2, used in an external combustion engine.

6. The fuel oil composition according to claim 5, wherein the external combustion engine is equipped with a hydraulic spray burner with a rated combustion capacity of 100 L / hour or less.

7. An ester of a fatty acid having 8 to 22 carbon atoms and an alkyl alcohol having 1 to 4 carbon atoms, as follows (a １ ) ~ (a ３ ) an alkyl fatty acid ester that satisfies all of the following conditions and (b １ ) ~ (b ４ A method for producing a fuel oil composition that satisfies all of the following (1) to (6): (a) １ ) Cetane number of 49.0 or higher (a ２ ) Acid value is 0.50 mg KOH / g or less (a ３ ) The residual carbon content of the 10% residual oil is 0.80% by mass or more and 1.50% by mass or less (b １ ) The kinematic viscosity at 50°C is 2,600 mm ２ / s or more 3.600mm ２ / s or less (b ２ ) Sulfur content is 0.400% by mass or less (b ３ ) Aromatic content of 50.0% by volume or more (b ４ ) Aromatic content of three or more rings is 10.0% by volume or more (1) Density at 15℃ is 0.8950 g / cm³ ３ (2) The kinematic viscosity at 50°C is 3,000 mm². ２ / s or more 3.500mm ２ / s or less (3) Sulfur content is 0.300% by mass or less (4) Aromatic content of three or more rings is 6.0% by volume or more (5) Residual carbon content of 10% residual oil is 0.21% by mass or more and 0.60% by mass or less (6) Cetane number is 31.0 or higher

Images