JP2008007616A - Fuel oil composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel oil composition with high flammability withstanding to use for a recent high performance engine and not causing clogging of a filter by wax in winter. <P>SOLUTION: The fuel oil composition is obtained using a gas oil fraction having 5 mass% to 70 mass% of content of 16 to 25C straight saturated hydrocarbon and manufactured by FT synthesis in which 10 vol% distillation temperature of distillation property is 100-300°C, and/or a gas oil and kerosine obtained by hydrocracking FT wax manufactured by FT synthesis. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel oil composition. More specifically, the present invention relates to an A heavy oil composition that has sufficient performance for recent high performance engines, has excellent low-temperature fluidity, and satisfies the JIS Class 1 heavy oil standard, which is excellent in filter oil passing performance at low temperatures.

Conventionally, as a base material of heavy oil A, straight-run kerosene obtained from an atmospheric distillation apparatus of crude oil or kerosene subjected to desulfurization treatment, straight-run light diesel oil or desulfurized light diesel oil, heavy diesel oil, and a light cycle obtained from a cracking device Oil, direct desulfurized oil obtained from direct desulfurization equipment is known. The conventional A heavy oil composition contains one or more of the above-mentioned base materials. In addition, it is manufactured by applying one or more kinds of normal pressure residual oil, direct desorption residual oil, and vacuum residual oil as residual carbon base materials. Moreover, additives such as a cetane number improver and a low temperature fluidity improver are blended with these A heavy oil compositions as necessary (see, for example, Non-Patent Document 1).
Seiichi Konishi, “Introduction to Fuel Engineering”, Saika Hanafusa, March 1991, p. 136-144

A heavy oil is widely used as fuel for external combustion equipment such as boilers, diesel engine equipment fuel for off-road use such as small fishing boats and construction machinery, and gas turbine equipment fuel.
Various combustion equipment using heavy fuel oil A is provided with a filter having an opening of 5 to 250 μm in the fuel system for the purpose of removing foreign substances in the fuel oil. However, when such a combustion device is used in winter, the filter is likely to be clogged with wax precipitated from A heavy oil.
Furthermore, with the recent increase in output and fuel efficiency of engines used in heavy fuel oil A, demand for higher performance is increasing year by year for heavy fuel oil A. When heavy fuel oil A is used as the fuel for these high-performance engines, there may be a problem with combustibility such as deterioration of ignitability and increased generation of soot.

Therefore, in order to solve such problems, studies have been made to improve the low temperature fluidity and combustibility of A heavy oil. To improve the low temperature fluidity, an aromatic compound is added and a low temperature fluidity improver is added. Methods such as addition and increase in residual oil have been proposed (see, for example, Patent Documents 1 to 3 and Non-Patent Document 2).
However, the A heavy oil obtained by the above-described methods has room for improvement in the following points, and none of them is still sufficient to be put to practical use as A heavy oil. That is, the increased blending of aromatic components causes an increase in the amount of dust in the combustion gas and poor ignition. In addition, the performance of the low temperature fluidity improver depends largely on the compatibility with the base material used, and it is difficult to obtain sufficient low temperature performance as A heavy oil simply by adding. The increase in the residual carbon base material may cause an increase in the amount of dust in the combustion gas, and the solubility with other base materials deteriorates, and there is a concern about filter oil permeability accompanying sludge generation at room temperature.
In addition, A heavy oil excellent in low-temperature performance often reduces the amount of paraffin and deteriorates combustibility. Thus, A heavy oil satisfying both low temperature performance and combustibility has not been obtained.
JP 2000-144152 A JP 2001-279272 A JP 2005-194423 A Koji Nomura, “Science of Marine Fuel”, Naruyamado, 1994, p. 164-166

  A heavy oil is used as boiler fuel and off-road diesel engine fuel. With the recent increase in output and fuel efficiency of engines used in A heavy oil, A heavy oil has higher performance. Requests are increasing year by year. When heavy fuel oil A is used as the fuel for these high-performance engines, there may be a problem related to combustibility such as deterioration of ignitability and increased occurrence of soot and increased frequency of cleaning in the burner and the furnace. On the other hand, since A heavy oil contains more heavy components than gasoline and kerosene, wax precipitation at low temperatures may be a problem. Wax precipitation at low temperatures may clog a filter for preventing contaminants in the fuel system, and in the worst case, fuel supply may not be possible. As a method for suppressing wax precipitation at low temperatures, a method of adding a fluidity improver is common, but under the actual severe winter conditions, a sufficient effect cannot be exhibited. Conventionally, a test based on a clogging point has been used to judge the filter clogging property at low temperatures. Although the low temperature fluidity is improved by adding a fluidity improver, this test method differs greatly from the actual use conditions because the cooling rate of the sample oil is rapidly cooled (about 40 ° C./hour). . It is known that the slower the cooling rate, the larger the precipitated wax and the clogging of the filter, and the evaluation based on the clogging point is insufficient. In general, A heavy oil excellent in low-temperature performance often has poor flammability, and A heavy oil satisfying all these performances is desired. Thus, A heavy oil satisfying both low temperature performance and combustibility is not obtained. An object of the present invention is to provide a fuel oil composition that can withstand use in high-performance engines in recent years and does not cause clogging of the filter by wax in winter.

As a result of intensive studies to solve the above problems, the present inventors have found that the use of a specific base material in combination results in high flammability and does not cause clogging of the filter by wax in winter. The present invention has been completed.
That is, the present invention is an FT synthesis in which the content of linear saturated hydrocarbons having 16 to 25 carbon atoms is 5% by mass or more and 70% by mass or less, and 10% by volume distillation temperature of distillation property is 100 to 300 ° C. The present invention relates to a fuel oil composition obtained by using gas oil fraction and / or kerosene obtained by hydrocracking FT wax produced by FT synthesis.

  According to the present invention, it is possible to obtain a fuel oil composition that has high combustibility, can withstand use in high-performance engines in recent years, and does not cause filter clogging with wax in winter.

Hereinafter, the present invention will be described in detail.
The fuel oil composition of the present invention has, as a constituent, [1] a linear saturated hydrocarbon content of 16 to 25 carbon atoms of 5% by mass or more and 70% by mass or less, and a distillation property of 10% by volume distillate. It is necessary to use a gas oil fraction produced by FT synthesis at a temperature of 100 to 300 ° C. and / or a gas oil hydrocracked from FT wax produced by FT synthesis and [2] kerosene.

  The linear saturated hydrocarbon content having 16 to 25 carbon atoms in the present invention is a value (mass%) measured using GC-FID. That is, a capillary column of methyl silicon (ULTRAALLOY-1) is used for the column, helium is used for the carrier gas, a hydrogen ion detector (FID) is used for the detector, a column length of 30 m, a carrier gas flow rate of 1.0 mL / min, and a splitting. It is a value measured under the conditions of ratio 1:79, sample injection temperature 360 ° C., column temperature rising condition 140 ° C. → (8 ° C./min)→355° C., detector temperature 360 ° C.

  The 10 vol% distillation temperature referred to in the present invention is a value measured according to JIS K 2254 "Petroleum products-Distillation test method-Atmospheric pressure distillation test method".

  The light oil fraction produced by FT synthesis as used in the present invention is a Fischer-Tropsch (FT) reaction applied to a mixed gas (also referred to as synthesis gas) mainly composed of hydrogen and carbon monoxide. It shows the liquid fraction corresponding to light oil obtained.

  The mixed gas used as the raw material for the FT synthesis in the present invention is a gas-containing substance that is oxidized using oxygen and / or water and / or carbon dioxide as an oxidant, and further shifted using water as necessary. It is obtained by adjusting to a predetermined hydrogen and carbon monoxide concentration by reaction. Substances containing carbon include natural gas, petroleum liquefied gas, methane gas, etc., gas components consisting of hydrocarbons that are gaseous at room temperature, petroleum asphalt, biomass, coal, waste such as building materials and garbage, sludge, In addition, mixed gas obtained by exposing heavy crude oil, unconventional petroleum resources, etc. that are difficult to process by ordinary methods to high temperatures is common, but mixed gas mainly composed of hydrogen and carbon monoxide As long as is obtained, the raw material is not limited.

  In the FT synthesis referred to in the present invention, a metal catalyst is used. As the active catalyst component, a Group 8 metal of the periodic table, for example, cobalt, ruthenium, rhodium, palladium, nickel, iron, etc., more preferably a Group 8 Group 4 metal is used. These active metals are generally used in the form of a catalyst obtained by being supported on a support such as silica or alumina. Moreover, catalyst performance can also be improved by using these catalysts in combination with a second metal in addition to the active metal. Examples of the second metal include alkali metals such as sodium and lithium, alkaline earth metals such as magnesium, zirconium, hafnium, and the like, and the chain growth probability that serves as an index for improving the conversion of carbon monoxide and the amount of wax produced. It is used appropriately according to the purpose, such as an increase in (α).

  The light oil obtained by hydrocracking the FT wax produced by FT synthesis as used in the present invention indicates a hydrocarbon mixture obtained by hydrocracking the paraffin wax produced by the FT reaction.

  The catalyst in the hydrocracking referred to in the present invention is generally a catalyst having a hydrogenation active metal supported on a carrier having a solid acid property. However, the form of the catalyst is limited as long as the catalyst can provide the same effect. It is not a thing.

  Examples of the carrier having a solid acid property include amorphous and crystalline zeolites. Specific examples include amorphous silica-alumina, silica-magnesia, silica-zirconia, silica-titania and zeolite faujasite type, beta type, MFI type, and mordenite type. Preferred are faujasite type, beta type, MFI type, and mordenite type zeolite, and more preferred are Y type and beta type. The Y type is preferably ultra-stabilized.

  The active metal is at least one metal selected from Group 6A and Group 8 metals of the Periodic Table. Preferably, it is at least one metal selected from Ni, Co, Mo, Pt, Pd and W. The active metal may be a combination of these metals, and examples thereof include Pt—Pd, Co—Mo, Ni—Mo, Ni—W, Ni—Co—Mo, and the like. It is necessary to include a preliminary sulfidation step when using.

  As the metal source, a general inorganic salt or a complex salt compound can be used, and as a supporting method, any method of a supporting method used in an ordinary hydrogenation catalyst such as an impregnation method or an ion exchange method can be used. When a plurality of metals are supported, they may be supported simultaneously using a mixed solution, or may be sequentially supported using a single solution. The metal solution may be an aqueous solution or an organic solvent.

  In the present invention, the hydrocracking catalyst can be used after a preliminary reduction treatment in a hydrogen stream. In general, when a gas containing hydrogen is circulated and heat of 200 ° C. or higher is applied according to a predetermined procedure, the active metal on the catalyst is reduced, and hydrogenation activity is exhibited.

The light oil fraction produced by the FT synthesis and the light oil obtained by hydrocracking the FT wax produced by the FT synthesis are used as a base material for the fuel oil composition of the present invention. Specifically, as the distillation properties, the 50% by volume distillation temperature is preferably 150 to 350 ° C., and the density at 15 ° C. is preferably in the range of 750 to 800 kg / m ³ .

  In the present invention, the light oil fraction produced by FT synthesis and the light oil obtained by hydrocracking the FT wax produced by FT synthesis preferably contain 90% by volume or more, more preferably 95% by volume or more. . When the saturation content is less than this range, the ignitability deteriorates when used as an off-road diesel engine fuel.

The kerosene in the present invention refers to a kerosene fraction obtained from an atmospheric distillation apparatus or a hydrocracking apparatus.
In the present invention, kerosene is used as a base material for the fuel oil composition of the present invention. Specifically, as the distillation properties, the 50 vol% distillation temperature is preferably 150 to 250 ° C, and the density at 15 ° C is preferably in the range of 750 to 850 kg / m ³ .
The kerosene in the present invention preferably has a cloud point of -20 ° C or lower, more preferably -25 ° C or lower. If the cloud point is less than this range, the low temperature fluidity deteriorates, which is not preferable.

  There are no particular restrictions on the blending ratio of the gas oil fraction produced by the FT synthesis and / or the gas oil hydrocracked from the FT wax produced by the FT synthesis that constitutes the fuel oil composition of the present invention. In order to fully exhibit the above, it is preferable to use a gas oil fraction produced by FT synthesis and a gas oil hydrocracked from FT wax produced by FT synthesis in an amount of 1% by volume or more based on the total amount of the fuel oil composition. More preferably, it is used at 20 volume% or more, more preferably 25 volume% or more, particularly preferably 30 volume% or more, most preferably 35 volume% or more. However, if the gas oil fraction produced by FT synthesis and the gas oil obtained by hydrocracking the FT wax produced by FT synthesis are increased, the low-temperature performance tends to deteriorate. It is preferably used, more preferably 80% by volume or less, and particularly preferably 75% by volume or less.

  In order to improve low temperature fluidity, kerosene is preferably used in an amount of 1% by volume or more based on the total amount of the fuel oil composition, more preferably 5% by volume or more, and more preferably 10% by volume or more. More preferably, it is most preferable to use 15 volume% or more. However, if kerosene is increased, the flash point tends to decrease. Therefore, it is preferably used at 50% by volume or less, more preferably 45% by volume or less, and 40% by volume or less. More preferably.

Conventionally, as A heavy oil base material, straight-run gas oil fraction obtained from atmospheric distillation apparatus or its desulfurized gas oil fraction, hydrocracked gas oil, fluid catalytic cracked gas oil, residual oil desulfurized gas oil fraction, hydrodesulfurized gas oil fraction Examples thereof include a denormalized paraffinic light oil fraction, a heavy light oil fraction, a light oil obtained by desulfurizing a vacuum gas oil, and a fluid catalytic cracking kerosene, which are residues obtained by removing normal paraffin content by extraction of a fraction or hydrorefined gas oil fraction. In this invention, unless the effect of this invention is impaired, 1 type (s) or 2 or more types of these can be mix | blended with the fuel oil composition of this invention.

A residual carbon base material is mix | blended with A heavy oil composition.
The type of the residual carbon base material is not particularly limited, and examples thereof include atmospheric residual oil, residual oil desulfurized heavy oil, vacuum residual oil, slurry oil, and extract oil. These may be used alone or in combination of two or more. Use. Here, the atmospheric residual oil is a residual oil obtained by distilling crude oil at atmospheric pressure using an atmospheric distillation apparatus. The residual oil desulfurized heavy oil is a heavy oil obtained when a normal pressure residual oil or a vacuum residual oil is desulfurized in a residual oil desulfurization apparatus. The vacuum residue is a residue obtained by distilling atmospheric residue under reduced pressure using a vacuum distillation apparatus. Slurry oil is residual oil obtained from a fluid catalytic cracker. Extract oil is an aromatic component that is not suitable for lubricating oil among the fractions extracted from the vacuum distillation apparatus for lubricating oil raw material by solvent extraction.

  The fuel oil composition of the present invention comprises a light oil fraction produced by the above-described FT synthesis and / or a gas oil hydrocracked from an FT wax produced by the FT synthesis, and kerosene.

The fuel oil composition of the present invention must satisfy the JIS Class 1 heavy oil standard. The JIS Class 1 heavy oil standard is a standard that satisfies “Class 1” defined in JIS K 2205 “Heavy oil”. Specifically, the flash point is 60 ° C. or higher, the pour point is 5 ° C. or lower, and the residual carbon content is 4% by mass. Hereinafter, it is necessary that the kinematic viscosity at 50 ° C. is 20 mm ² / s or less, the sulfur content is 2.0 mass% or less, the water content is 0.3 volume% or less, and the ash content is 0.05 mass% or less.

  The flash point of the fuel oil composition of the present invention must satisfy JIS Class 1 heavy oil standard of 60 ° C. or higher. If the flash point is less than 60 ° C., it cannot be handled as a heavy fuel oil composition for safety reasons. For the same reason, the flash point is preferably 61 ° C. or higher, and more preferably 62 ° C. or higher. In the present invention, the flash point means a value obtained in accordance with JIS K 2265 “Crude oil and petroleum products—flash point test method”.

  Moreover, the pour point of the fuel oil composition of the present invention needs to satisfy 5 ° C. or less, which is a JIS Class 1 heavy oil standard. Furthermore, it is preferable that it is 2.5 degrees C or less from a viewpoint of low-temperature fluidity | liquidity. Here, the pour point means a pour point measured by JIS K 2269 “Pour point of crude oil and petroleum products and cloud point test method of petroleum products”.

  The residual carbon content in the fuel oil composition of the present invention must satisfy 4% by mass or less, which is a JIS Class 1 heavy oil standard. Furthermore, it is preferably 3% by mass or less, more preferably 2% by mass or less, from the viewpoint of reducing fine particles and PM and maintaining the performance of the exhaust gas aftertreatment device mounted on the engine. The residual carbon content here means a residual carbon content measured by JIS K 2270 “Crude oil and petroleum products—residual carbon content test method”.

  Although there is no restriction | limiting in particular about the 10% residual carbon content of the fuel oil composition of this invention, from the point of "the residual carbon content of 10% residual oil 0.2 mass% or more" which is a tax exemption condition of A heavy oil on tax law It is desired to be 0.2% by mass or more. However, from the standpoint of preventing filter clogging by sludge, it is preferably 0.8% by mass or less, and more preferably 0.6% by mass or less. The 10% residual carbon content here means the residual carbon content measured by JIS K 2270 “Crude oil and petroleum products—residual carbon content test method”.

The kinematic viscosity at 50 ° C. of the fuel oil composition of the present invention needs to be 20 mm ² / s or less, which is a JIS class 1 heavy oil standard, preferably 18 mm ² / s or less, and 15 mm ² / s or less. It is more preferable that If the kinematic viscosity exceeds 20 mm ² / s, the resistance inside the fuel injection system increases, the injection system becomes unstable, and the concentrations of NOx and PM in the exhaust gas increase. The kinematic viscosity here means the kinematic viscosity measured by JIS K 2283 “Crude oil and petroleum products—Kinematic viscosity test method and viscosity index calculation method”.

  The sulfur content in the fuel oil composition of the present invention must satisfy 2% by mass or less, which is a JIS Class 1 heavy oil standard. Furthermore, from the viewpoint of reducing fine particles and PM, and from the viewpoint of maintaining the performance of the exhaust gas aftertreatment device mounted on the engine, it is preferably 1.5% by mass or less, and more preferably 1% by mass or less. A sulfur content here means the residual carbon content measured by JISK2541 "crude oil and petroleum products-sulfur content test method".

  In the fuel oil composition of the present invention, the water content needs to satisfy the JIS Class 1 heavy oil standard of 0.3% by volume or less. Furthermore, from the viewpoint of adverse effects on the member, it is preferably 0.2% by volume or less, and more preferably 0.1% by volume or less. In addition, the water | moisture content said by this invention means the value measured by JISK2275 "moisture test method (crude oil and petroleum products)".

  In the fuel oil composition of the present invention, the ash content must satisfy 0.05 mass% or less, which is a JIS Class 1 heavy oil standard. Furthermore, from the viewpoint of reducing fine particles and PM, the content is preferably 0.04% by mass or less, and more preferably 0.03% by mass or less. The ash content in the present invention means a value measured by JIS K 2272 “Crude oil and petroleum product ash content and sulfate ash test method”.

The cetane index of the fuel oil composition of the present invention is not particularly limited, but is preferably 45 or more and more preferably 50 or more from the viewpoint of combustibility. In the present invention, the cetane index means a value obtained in accordance with JIS K 2204-1992 “light oil”. That is, it is calculated by the following formula.
[Cetane index (C) = 0.49083 + 1.06577 (X)-0.0010522 (X) ² ]
[X = 97.833 (log A) ² +2.2088 B log A + 0.01247 B ² −423.51 log A−4.7808 B + 419.59]
A: (9/5) [50% distillation temperature at 101.3 kPa (760 mmHg) (° C.)] + 32
B: API volume (50 volume% distillation temperature (° C.) at 101.3 kPa (760 mmHg) is measured according to JIS K 2254 “Petroleum products—distillation test method”, and API degree is determined according to JIS K 2249 “crude oil and petroleum products— Calculated from the density at 15 ° C. by “density test method and density / mass / capacity conversion table”)

  The cloud point of the fuel oil composition of the present invention is not particularly limited, but it is preferably 7 ° C. or less from the viewpoint of reducing wax precipitation at a low temperature that clogs a filter for preventing impurities in the fuel system. 6 ° C. or lower, more preferably 5 ° C. or lower, and most preferably 4 ° C. or lower. In the present invention, the cloud point means a value obtained in accordance with JIS K 2269 “Pour point of crude oil and petroleum products and cloud point test method of petroleum products”.

  The CFPP (clogging point) of the fuel oil composition of the present invention is not particularly limited, but it is preferably −3 ° C. or lower because it is superior in terms of preventing filter clogging due to wax in winter. It is more preferably −5 ° C. or lower, and most preferably −7 ° C. or lower. In the present invention, CFPP means a value obtained in accordance with JIS K 2288 “Diesel Oil—Clogging Point Test Method”.

  The corrected clogging point of the fuel oil composition of the present invention is not particularly limited, but it is preferably −3 ° C. or lower, and −5 ° C. or lower because it is superior in terms of preventing filter clogging due to wax in winter. It is more preferable that If the corrected clogging point is higher than −3 ° C., the filter clogging of the pump or burner tends to occur in winter, which is not preferable. In addition, the correction clogging point as used in the field of this invention means the value measured by the correction method 4 described in the description of Petroleum Institute standard JPI-5S-47-96 "Low temperature fluidity test method of A heavy oil".

  Further, the nitrogen content of the fuel oil composition of the present invention is not particularly limited, but in order to reduce harmful substances in the exhaust gas, it is preferably 0.02% by mass or less, and 0.015% by mass or less. More preferably, it is most preferably 0.01% by mass or less. In the present invention, the nitrogen content means a value representing a value obtained according to JIS K 2609 “Crude oil and petroleum products—nitrogen content test method”.

Moreover, although there is no restriction | limiting about the distillation property of the fuel oil composition of this invention, Usually, what satisfy | fills the following property is preferable.
10 vol% distillation temperature (T10): 180-280 ° C
50 volume% distillation temperature (T50): 240-340 degreeC
90 volume% distillation temperature (T90): 280-380 degreeC
In the present invention, the distillation property means a value obtained according to JIS K 2254 “Petroleum products—Distillation test method”.

Although there is no restriction | limiting in particular about the density of the fuel oil composition of this invention, Usually, it is preferable that it is 750-920 kg / m < ³ >. In the present invention, the density means a value obtained based on JIS K 2249 “Crude oil and petroleum products—density test method and density / mass / capacity conversion table”.

  Moreover, an additive can be mix | blended with the fuel oil composition of this invention as needed. Various additives such as cetane number improvers, antioxidants, stabilizers, dispersants, metal deactivators, microbial disinfectants, auxiliary agents, antistatic agents, discriminating agents, colorants, etc. These additives can be added as appropriate. Among these, it is preferable to add a fluidity improver because it is excellent in the effect of preventing filter clogging by wax in winter. As the fluidity improver, for example, polymer-type additives such as ethylene-vinyl acetate copolymer and ethylene-α-olefin copolymer, oil-soluble dispersant-type additives, and alkersuccinic acid can be used. Moreover, there is no restriction | limiting about the addition amount of a fluid improvement agent, However, It is preferable that it is 0.001-0.1 volume% on the basis of the fuel oil composition whole quantity, and is 0.01-0.05 mass%. It is more preferable.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

[Examples 1 and 2 and Comparative Examples 1 to 3]
Each base material (light oil, kerosene, straight-run gas oil, atmospheric residual oil obtained by hydrocracking FT wax produced by FT synthesis and / or FT wax produced by FT synthesis) having the properties shown in Table 1 The A fuel oil compositions of Examples 1 and 2 and Comparative Examples 1 to 3 were prepared by mixing at a volume ratio as shown in each example of Table 2, and the properties of each of these prepared compositions are shown in Table 2. About each sample oil (each composition), low temperature fluidity performance evaluation and flammability performance evaluation were performed by the following method. The results are shown in Table 3.

(Low temperature fluidity performance evaluation)
A 20 L pail can was prepared as a sample container, and a hole into which the sample suction tube was inserted was provided on the top surface of the pail can. The hole was formed at the midpoint of a straight line connecting the center of the upper surface and the point on the outer periphery. On the other hand, a copper tube having an outer diameter of 10 mm was prepared as a sample suction tube, and one end thereof was connected to an inlet of a filter (Nepon Corporation, code No. 120267) via a silicon rubber tube. Moreover, the outlet of the filter was connected to a suction pump through a copper tube. As the suction pump, a pump capable of adjusting the oil flow rate within a range of 1 to 10 L / hr was used.
Next, about 15 L of a sample (A heavy oil composition) having a temperature of 20 to 25 ° C. is put in the above-mentioned pail can, and a lid with a sample suction tube is put on the hole on the upper surface of the pail can. The pump was accommodated in a thermostat, the pump was driven, and the pump pressure was adjusted so that the oil flow rate was 9.5 ± 0.2 L / hr. As the low-temperature thermostatic bath, a thermostatic bath having a program temperature adjusting function and capable of cooling to −30 ° C. or less within a temperature system of ± 0.5 ° C. was used. After the pail can and the filter were accommodated in the low temperature thermostat, the inside of the low temperature thermostat was cooled with a predetermined temperature profile, and the suction pump was driven. More specifically, the sample was cooled from a temperature 8 ° C. higher than the cloud point of the sample to a predetermined temperature at a cooling rate of 1 ° C./hr. The temperature was held for 3 hours, and the oil passage limit was determined by measuring the pressure with a pressure gauge. Judgment of the oil passage limit is accepted when the differential pressure is 33 kPa (250 mmHg) or less during oil passage for 60 minutes at the holding temperature, and is rejected when it exceeds 33 kPa, and held at 1 ° C intervals until it fails. The test was repeated at a lower temperature. The highest temperature (clogging temperature) at which the judgment was rejected was used as an index for evaluating the low temperature performance. In addition, the sample was replaced with new oil for each test. A clogging temperature of −15 ° C. or lower was judged good (◯), and a temperature of −14 ° C. or higher was judged bad (x). The obtained results are shown in Table 3.

(Flammability performance evaluation)
The combustion performance was evaluated by measuring the ignition delay by the following method. Ignition delay adversely affects engine performance and exhaust gas, and is a major cause of trouble in recent high-performance engines. Using a fuel ignitability tester having a combustion chamber volume of 1 liter, fuel was injected into air having a pressure of 45 barrels and a temperature of 450 ° C., and the time from injection to ignition was measured as the ignition delay time. An ignition delay time of less than 5 ms was judged as good (◯), and 5 ms or more was judged as bad (x). The obtained results are shown in Table 3.

  As is clear from the results in Table 3, the A heavy oil compositions of Examples 1 and 2 according to the present invention are both excellent in ignitability and excellent in combustibility, and have sufficient performance for recent high performance engines. It can be seen that the filter has excellent oil passing performance at low temperatures.

Claims (4)

  A light oil fraction produced by FT synthesis having a straight chain saturated hydrocarbon content of 16 to 25 carbon atoms of 5% by mass to 70% by mass and having a distillation property of 10% by volume distillation temperature of 100 to 300 ° C. And / or a fuel oil composition obtained by using light oil and kerosene obtained by hydrocracking FT wax produced by FT synthesis.   1% by volume or more of a light oil fraction produced by FT synthesis with a 50 volume% distillation temperature of 150 to 350 ° C. and a gas oil hydrocracked from FT wax produced by FT synthesis based on the total amount of the fuel oil composition. The fuel oil composition according to claim 1.   It is characterized by blending 1% by volume or more of a light oil fraction produced by FT synthesis containing 90% by volume or more of a saturated component and a gas oil hydrocracked from FT wax produced by FT synthesis based on the total amount of the fuel oil composition. The fuel oil composition according to claim 1.   The fuel oil composition according to claim 1, wherein kerosene having a 50 vol% distillation temperature of 150 to 250 ° C is blended in an amount of 1 vol% or more based on the total amount of the fuel oil composition.