JP4729424B2 - Light oil composition - Google Patents

Description

  The present invention relates to a light oil composition, and more particularly to a light oil composition that is suitably used in winter or in cold regions.

  Conventionally, as a base material for light oil, straight-run gas oil obtained from a crude oil atmospheric distillation apparatus, straight-run kerosene obtained by crude oil atmospheric distillation, and the like have been subjected to hydrorefining treatment or hydrodesulfurization treatment. Are known. Moreover, additives such as a cetane number improver and a detergent are blended with these light oil bases as necessary.

Recently, from the viewpoint of improving the air environment and reducing the environmental load, it is required to clean diesel engine exhaust gas. Accordingly, in order to meet such demands, development of a light oil base material capable of reducing pollutants in diesel exhaust gas is being promoted. For example, Patent Document 1 below describes that diesel particulate emissions can be reduced by a compression ignition engine fuel in which the content of sulfur and aromatic compounds and the ratio of isoparaffin to normal paraffin satisfy specific conditions.
JP 2005-529213 A

  However, even the above conventional light oil has room for improvement in terms of fuel efficiency, and in particular, the ignitability tends to decrease in winter or cold regions. Further, in the case of conventional light oil, the low-temperature fluidity tends to be insufficient, and the operating performance such as low-temperature startability tends to be reduced in combination with the low ignitability described above.

  This invention is made | formed in view of such a situation, and it aims at providing the light oil composition which is excellent in ignitability and low-temperature fluidity | liquidity, and can be used conveniently in winter or a cold region.

  In order to achieve the above object, the present inventors first analyzed the composition of light oil using a gas chromatograph / time-of-flight mass spectrometer (hereinafter abbreviated as “GC-TOFMS”), and the composition was ignited. The effects on the flowability and low temperature fluidity were investigated. As a result, the ignitability and low-temperature fluidity of the light oil composition can be drastically improved by ensuring that the molar ratio of the two or more branched isoparaffins to the one branched isoparaffin satisfies the specific conditions within a specific carbon number range. As a result, the present invention has been completed.

  That is, in the light oil composition of the present invention, in the range of 10 to 21 carbon atoms, the molar ratio of 2 or more branched isoparaffins having m carbon atoms to 1 branched isoparaffin having m carbon atoms (m is an integer of 10 to 21). In the range of 0.05 to 3.5 and in the range of 22 to 25 carbon atoms, the molar ratio of n-branched or more isoparaffins having n carbon atoms to n-branched isoparaffins having n carbon atoms (n is an integer of 22 to 25) ) Is 0.1 to 10.0.

  As described above, in each of the range of 10 to 21 carbon atoms and the range of 22 to 25 carbon atoms, the molar ratio of one-branch isoparaffin and two or more branch isoparaffins having the same carbon number satisfies the above-mentioned specific condition. By doing so, both ignitability and low-temperature fluidity can be dramatically improved, and as a result, it is possible to realize a light oil composition that can be suitably used in winter or cold regions.

Here, the molar ratio of two or more branched isoparaffins to one branched isoparaffin at each carbon number can be obtained using GC-TOFMS as described above. In GC-TOFMS, first, constituent components of a sample are separated by gas chromatography, and each separated component is ionized. Next, the ions are mass-separated based on the flight speed when a constant acceleration voltage is applied to the ions depending on the mass of the ions, and a mass spectrum is obtained based on the difference in arrival time to the ion detector. As the ionization method in GC-TOFMS, the FI ionization method is preferable because the generation of fragment ions can be suppressed and the measurement accuracy of the molar ratio of two or more branched isoparaffins to one branched isoparaffin can be further improved. The measurement apparatus and measurement conditions in the present invention are shown below.
(GC department)
Apparatus: HEWLETT PACKARD, HP6890 Series GC Systm & Injector
Column: A client HP-5 (30 m × 0.32 mmφ, 0.25 μm-film)
Carrier gas: He, 1.4 mL / min (constant flow)
Inlet temperature: 320 ° C
Injection mode: split (split ratio = 1: 100)
Oven temperature: held at 50 ° C. for 5 minutes, heated at 5 ° C./min, and held at 320 ° C. for 6 minutes: Injection volume: 1 μL
(TOFMS Department)
Device: JEOL Ltd., JMS-T100GC
Counter electrode voltage: 10.0 kV
Ionization method: FI + (field ionization)
GC interface temperature: 250 ° C
Measurement mass range: 35-500.

  And based on said measurement data, for every component with the same carbon number, by calculating | requiring the ratio of the sum total of the intensity | strength of 1 branch isoparaffin, and the intensity | strength of 2 or more branch isoparaffin, 1 in each carbon number is calculated | required. A molar ratio of two or more branched isoparaffins to branched isoparaffins can be obtained. The molar ratio may be obtained directly from the mass spectrum, but based on the mass spectrum data, create a graph showing the correlation between the retention time and the intensity of gas chromatography for each component having the same carbon number, The peak area ratio of each component in the graph may be a molar ratio.

FIG. 1 is a graph showing an example of the correlation between retention time and intensity of gas chromatography of components having the same carbon number. In FIG. 1, the peaks in regions A, B, and C are peaks corresponding to normal paraffin, one branched isoparaffin, and two or more branched isoparaffins, respectively. The molar ratio of the two or more branched isoparaffins to the one branched isoparaffin defined in the present invention is obtained as the ratio of the peak area S _C of the region C to the peak area S _B of the region _B (S _C / S _B ).

  In the development of conventional light oil, as described in Patent Document 1 above, the ratio of normal paraffin to isoparaffin is used as an index, and the composition is examined by focusing on the number of branches of isoparaffin. There are few examples. In view of such a conventional technical level, the gas oil composition of the present invention preferably has a molar ratio of two or more branched isoparaffins to one branched isoparaffin as an index of light oil ignitability and low-temperature fluidity. This is the first time based on the knowledge of the present inventors that GC-TOFMS is useful as a technique for measuring the above, and the above-described effects of the present invention can be said to be extremely unexpected.

  In the light oil composition of this invention, it is preferable that a cloud point is 0 degrees C or less and a pour point is -7.5 degrees C or less.

  In the light oil composition of the present invention, the cetane number is 65 or more, the sulfur content is 10 mass ppm or less, the aromatic content is 1 mass% or less, and the naphthene content is It is preferably 5% by mass or less, and the clogging point is preferably −5 ° C. or less.

  As described above, according to the present invention, there is provided a light oil composition that is excellent in ignitability and low-temperature fluidity and can be suitably used in winter or cold regions.

  Hereinafter, preferred embodiments of the present invention will be described in detail.

The light oil composition of the present invention is characterized by satisfying both of the following conditions (A) and (B).
(A) In the range of 10 to 21 carbon atoms, the molar ratio (m is an integer of 10 to 21) of 0.05 to 3.5 is a molar ratio of 2 or more branched isoparaffins of carbon number m to 1 branched isoparaffins of carbon number m. Be.
(B) In the range of 22 to 25 carbon atoms, the molar ratio of n-branch or more isoparaffins having n carbon atoms to 1-branched isoparaffins having n carbon atoms (n is an integer of 22 to 25) is 0.1 to 10.0. Be.

  Regarding the above condition (A), the molar ratio (m is an integer of 10 to 21) of the isoparaffin having 2 or more carbon atoms to the 1-branched isoparaffin having 1 to 5 carbon atoms in the range of 10 to 21 carbon atoms is as described above. It is necessary to be 0.05 to 3.5, preferably 0.1 to 3.2, more preferably 0.15 to 2.8, and still more preferably 0.2 to 2.5. When the molar ratio is less than 0.05, the calorific value is decreased, and the fuel consumption per capacity is reduced. Moreover, if the said molar ratio exceeds 3.5, ignitability will fall.

  In addition, regarding the condition (B), the molar ratio of n-branched or more isoparaffins having n carbon atoms to n-branching isoparaffins having n carbon atoms in the range of 22 to 25 carbon atoms (n is an integer of 22 to 25) is as described above. 0.1 to 10.0 as described above, preferably 0.3 to 9.0, more preferably 0.4 to 8.0, and still more preferably 0.5 to 7.0. . If the molar ratio is less than 0.1, the low-temperature actual vehicle performance is insufficient, and if it exceeds 10.0, the viscosity increases and appropriate injection control cannot be performed.

  The aromatic content in the light oil composition of the present invention is not particularly limited, but is preferably 15% by volume or less, more preferably 10% by volume based on the total amount of the composition from the viewpoint of suppressing the production of PM and the like. % Or less, more preferably 5% by volume or less, and particularly preferably 1% by volume or less. The “aromatic content” as used in the present invention refers to the JPI-5S-49-97 “Hydrocarbon Type Test Method—High Performance Liquid Chromatograph Method” published by the Japan Petroleum Institute. It means the volume percentage (volume%) of the aromatic content measured according to the standard.

  Further, the content of naphthene in the light oil composition of the present invention is not particularly limited, but is preferably 50% by volume or less, more preferably 30% by volume based on the total amount of the composition from the viewpoint of suppressing the production of PM and the like. Hereinafter, it is more preferably 15% by volume or less, particularly preferably 10% by volume or less. The “aromatic content” as used in the present invention refers to a mass percentage of naphthene based on ASTM D2425 “Standard Test Method for Hydrocarbon Types in Middle Distilates by Mass Spectrometry”. means.

  Further, the sulfur content of the light oil composition of the present invention is preferably 10 mass ppm or less, based on the total amount of the composition, since the purification performance of the exhaust gas aftertreatment device of a diesel vehicle can be maintained well. Preferably it is 5 mass ppm or less, More preferably, it is 3 mass ppm or less, Most preferably, it is 1 mass ppm or less. The “sulfur content” in the present invention means a value measured according to JIS K 2541 “Sulfur content test method”.

  The base material constituting the light oil composition of the present invention is not particularly limited as long as the light oil composition satisfies the above conditions (A) and (B), and the petroleum-based light oil base material, the petroleum-based kerosene base material, the synthetic-based light oil. One of the substrate and the synthetic kerosene substrate can be used alone or in combination of two or more. In addition, when using combining 2 or more types of base materials, it is not necessary for each base material to satisfy | fill said conditions (A) and (B) independently, and the light oil composition after mixing them is the said conditions (A). (B) should be satisfied.

  Specific examples of the petroleum-based light oil base used in the present invention include straight-run gas oil obtained from a crude oil atmospheric distillation apparatus; straight-run heavy oil and residual oil obtained from an atmospheric distillation apparatus; Vacuum gas oil obtained by subjecting to vacuum distillation equipment; hydrorefined gas oil obtained by hydrorefining straight-run gas oil or vacuum gas oil; straight-run gas oil or vacuum gas oil in one stage or more under severer conditions than ordinary hydrorefining Hydrodesulfurized light oil obtained by hydrodesulfurization in stages; hydrocracked light oil obtained by hydrocracking the above various light oil base materials, and the like.

  Further, as the petroleum-based kerosene base, specifically, for example, straight-run kerosene obtained from a crude oil atmospheric distillation apparatus; straight-run heavy oil or residual oil obtained from an atmospheric distillation apparatus is subjected to a vacuum distillation apparatus. Obtained reduced kerosene; hydrorefined kerosene obtained by hydrorefining straight-run kerosene or reduced-pressure kerosene; straight-run kerosene or depressurized kerosene is hydrogenated in one or more stages under conditions severer than ordinary hydrorefining Examples include hydrodesulfurized kerosene obtained by desulfurization; hydrocracked kerosene obtained by hydrocracking the above various kerosene substrates.

In addition, in this invention, when using a petroleum-type light oil base material or a petroleum-type kerosene base material, the various process conditions at the time of manufacturing these petroleum-type base materials can be selected suitably. For example, the hydrogen partial pressure during hydrodesulfurization is preferably 1 MPa or more, more preferably 3 MPa or more, and particularly preferably 5 MPa or more. The upper limit of the hydrogen partial pressure is not particularly limited, but is preferably 10 MPa or less from the viewpoint of pressure resistance of the reactor. The reaction temperature during hydrodesulfurization is preferably 300 ° C. or higher, more preferably 320 ° C. or higher, and particularly preferably 340 ° C. or higher. The upper limit of the reaction temperature is not particularly limited, but is preferably 400 ° C. or lower from the viewpoint of heat resistance of the reactor. The liquid hourly space velocity during the hydrodesulfurization is preferably ^{6h -1} or less, ^{4h -1,} more preferably less, ^{2h -1} or less are especially preferred. The lower limit of the liquid space velocity is not particularly limited, but is preferably 0.1 h ⁻¹ or more from the viewpoint of drift. Further, the catalyst used for the hydrodesulfurization is not particularly limited, and examples thereof include those using a combination of two or three kinds of metals such as Ni, Co, Mo, W, Pd, and Pt. it can. Specifically, catalysts such as Co—Mo, Ni—Mo, Ni—Co—Mo, and Ni—W can be preferably used. Among them, from the viewpoint of versatility, Co—Mo, Ni— A Mo-based catalyst is more preferable.

  The “synthetic light oil base material” refers to a light oil base material obtained by chemically synthesizing natural gas, asphalt content, coal, and the like as raw materials. Chemical synthesis methods include indirect liquefaction methods and direct liquefaction methods, and typical synthesis methods include Fischer-Tropsch synthesis methods. The synthetic light oil base used in the present invention is limited by these production methods. Is not to be done. Synthetic light oil bases are generally composed of saturated hydrocarbons, and are composed of normal paraffins, isoparaffins, and naphthenes. That is, the synthetic light oil base generally contains almost no aromatic component. Therefore, when reducing the aromatic content of the light oil composition, it is preferable to use a synthetic light oil base material.

  The “synthetic kerosene base material” refers to a kerosene base material obtained by chemically synthesizing natural gas, asphalt content, coal, and the like. Chemical synthesis methods include indirect liquefaction methods and direct liquefaction methods, and typical synthesis methods include Fischer-Tropsch synthesis methods. The synthetic kerosene base material used in the present invention is limited by these production methods. Is not to be done. Synthetic kerosene bases are generally composed of saturated hydrocarbons, and are composed of normal paraffins, isoparaffins, and naphthenes. That is, the synthetic kerosene base generally contains almost no aromatic content. Therefore, when reducing the aromatic content of a light oil composition, it is preferable to use a synthetic kerosene base material.

  The light oil composition of the present invention may contain one or more of the above petroleum-based base materials and / or synthetic base materials, and among them, an environment such as a sulfur content and an aromatic content. It is preferable to contain a synthetic light oil base and / or a synthetic kerosene base as an essential component from the viewpoint of reducing the after-product that increases the load. The total content of the synthetic light oil base and / or the synthetic kerosene base is preferably 20% by volume or more, more preferably 30% by volume or more, and 40% by volume based on the total amount of the composition. % Or more, more preferably 50% by volume or more.

  Moreover, although the light oil composition of this invention may be comprised only with said light oil base material and / or a kerosene base material, it can contain a low-temperature fluidity improver as needed. Specific examples of the low temperature fluidity improver include linear compounds such as ethylene-unsaturated ester copolymers represented by ethylene-vinyl acetate copolymers, alkenyl succinic acid amides, and dibehenic acid esters of polyethylene glycol. , Low temperature fluidity improvers such as comb polymers composed of alkyl fumarate or alkyl itaconate-unsaturated ester copolymers, acids such as phthalic acid, succinic acid, ethylenediaminetetraacetic acid, nitriloacetic acid, or acid anhydrides thereof, etc. And a low temperature fluidity improver containing a polar nitrogen compound consisting of a reaction product of a hydrocarbyl-substituted amine and the like, and one or more of these compounds may be used in combination. Among these, from the viewpoint of versatility, an ethylene-vinyl acetate copolymer additive and a low-temperature fluidity improver containing a polar nitrogen compound can be preferably used to prevent wax crystal refinement and prevent wax aggregation and sedimentation. Therefore, it is more preferable to use a low temperature fluidity improver containing a polar nitrogen compound.

  The content of the low temperature fluidity improver is preferably 50 to 500 mg / L, more preferably 100 to 300 mg / L, based on the total amount of the composition. If the content of the low temperature fluidity improver is less than the lower limit, the effect of improving the low temperature fluidity due to the addition tends to be insufficient. Moreover, even if content of a low-temperature fluidity improver exceeds the said upper limit, it exists in the tendency for the further improvement effect of the low-temperature fluidity suitable for content not to be acquired.

  Further, the light oil composition of the present invention can further contain a lubricity improver. As the lubricity improver, one or more of lubricity improvers such as ester, carboxylic acid, alcohol, phenol, and amine can be used. Among these, from the viewpoint of versatility, the use of ester-based and carboxylic acid-based lubricity improvers is preferable. Furthermore, an ester-based lubricity improver is preferable from the viewpoint that the effect of addition with respect to the concentration of addition hardly reaches saturation and the WS1.4 value of HFRR can be further reduced, and the initial response of the effect of addition with respect to the concentration of addition is high. Carboxylic acid type lubricity improvers are preferred from the viewpoint that the amount of addition of can be reduced.

  Examples of the ester-based lubricity improver include carboxylic acid esters of glycerin, and specific examples include glycerin esters such as linoleic acid, oleic acid, salicylic acid, palmitic acid, myristic acid, hexadecenoic acid, and the like. 1 type or 2 types or more can be used suitably.

  The content of the lubricity improver is preferably 25 to 500 mg / L, more preferably 25 to 300 mg / L, still more preferably 25 to 200 mg / L, based on the total amount of the composition. When the content of the lubricity improver is less than the lower limit, the lubricity improving effect due to the addition tends to be insufficient. Moreover, even if content of a lubricity improver exceeds the said upper limit, it exists in the tendency for the further improvement effect of the low temperature fluidity suitable for content not to be acquired.

  Moreover, the light oil composition of this invention may further contain additives other than said low-temperature fluidity improver or lubricity improver. Such additives include detergents such as alkenyl succinic acid derivatives, carboxylic acid amine salts, antioxidants such as phenols and amines, metal deactivators such as salicylidene derivatives, and anti-icing agents such as polyglycol ethers. , Corrosion inhibitors such as aliphatic amines and alkenyl succinic acid esters, antistatic agents such as anionic, cationic and amphoteric surfactants, colorants such as azo dyes, antifoaming agents such as silicon Can do. These other additives can be added singly or in combination of several kinds. Although the addition amount can also be selected as appropriate, the total amount of other additives can be, for example, 0.5% by mass or less, and preferably 0.2% by mass or less, based on the light oil composition. In addition, the addition amount whole quantity here means the addition amount as an active ingredient of an additive.

  The light oil composition of the present invention preferably satisfies the following conditions in addition to the above conditions (A) and (B) from the viewpoint of further improving various performances.

  The cloud point of the light oil composition of the present invention is preferably 0 ° C. or lower, more preferably −2 ° C. or lower, still more preferably −5 ° C. or lower, particularly preferably −8 ° C. or lower. When the cloud point is 0 ° C. or lower, the wax tends to be easily dissolved even if the wax adheres to the filter of the fuel injection device of the diesel vehicle. The “cloud point” in the present invention means a cloud point measured in accordance with JIS K 2269 “Pour point of crude oil and petroleum products and cloud point test method of petroleum products”.

  Moreover, the slow cooling cloud point of the light oil composition of this invention becomes like this. Preferably it is 0 degrees C or less, More preferably, it is -2 degrees C or less, More preferably, it is -5 degrees C or less, Most preferably, it is -8 degrees C or less. When the slow cooling cloud point is 0 ° C. or less, even if wax adheres to the filter of the fuel injection device of a diesel vehicle, the wax tends to be easily dissolved. The “slow cooling cloud point” in the present invention means a value measured as follows. That is, a sample is put in a sample container whose bottom surface is an aluminum surface so that the thickness is 1.5 mm, and light is irradiated from a height of 3 mm from the bottom surface of the container. In this state, the temperature is gradually cooled at 0.5 ° C./min from a temperature 10 ° C. or more higher than the above cloud point, and the temperature at which the amount of reflected light becomes 7/8 or less of the irradiated light (gradual cooling cloud point) is 0. Detect in 1 ℃ unit.

  In addition, the pour point of the light oil composition of the present invention is preferably −7.5 ° C. or less, more preferably −10 ° C. or less, and still more preferably, from the viewpoint of ensuring fluidity in a fuel line in a diesel vehicle. It is −15 ° C. or lower, particularly preferably −20 ° C. or lower. The “pour point” in the present invention means a pour point measured in accordance with JIS K 2269 “Pour point of crude oil and petroleum products and cloud point test method for petroleum products”.

  Further, the cetane index of the light oil composition of the present invention is preferably 65 or more, more preferably 70 or more, still more preferably 73 or more, and particularly preferably 75 or more, from the viewpoint of ignitability.

  Further, the cetane number of the light oil composition of the present invention is preferably 65 or more, more preferably 70 or more, still more preferably 73 or more, and particularly preferably 75 or more, from the viewpoint of ignitability.

  The “cetane index” and “cetane number” as used in the present invention are values measured according to JIS K 2280 “Petroleum products-fuel oil-octane number and cetane number test method and cetane index calculation method”, respectively. means.

  Further, the clogging point of the light oil composition of the present invention is preferably −5 ° C. or less, more preferably −6 ° C. or less, and still more preferably because clogging of a filter provided in a fuel injection device of a diesel vehicle can be suppressed. Is −7 ° C. or lower, particularly preferably −8 ° C. or lower. The “clogging point” in the present invention means a value measured in accordance with JIS K 2288 “Petroleum product—light oil—clogging point test method”.

Further, the kinematic viscosity at 30 ° C. of the light oil composition of the present invention is preferably 1.7 mm ² / s or more, more preferably 2.0 mm ² / s or more, still more preferably 2.3 mm ² / s or more, particularly preferably. 4 are 2.5 mm ² / s or more, and preferably 5.0 mm ² / s or less, more preferably 4,7mm ² / s or less, more preferably 4.5 mm ² / s or less, particularly preferably. 3 mm ² / s or less. When the kinematic viscosity at 30 ° C. is less than the lower limit value, starting failure tends to occur when the diesel vehicle is used at a relatively high temperature, and the engine rotation tends to become unstable during idling. It is in. On the other hand, when the kinematic viscosity at 30 ° C. exceeds the upper limit, the amount of black smoke in the exhaust gas tends to increase. In the present invention, “kinematic viscosity at 30 ° C.” means a value measured according to JIS K 2283 “Crude oil and petroleum products—Kinematic viscosity test method and viscosity index calculation method”.

  The flash point of the light oil composition of the present invention is preferably 45 ° C or higher, more preferably 50 ° C or higher, further preferably 53 ° C or higher, particularly preferably 55 ° C or higher, from the viewpoint of safety during handling. It is. The “flash point” in the present invention means a value measured in accordance with JIS K 2265 “Crude oil and petroleum products—flash point test method”.

  The initial boiling point (hereinafter abbreviated as “IBP”) of the light oil composition of the present invention is preferably 140 ° C. or higher, more preferably 145 ° C. or higher, still more preferably 150 ° C. or higher, particularly Preferably it is 155 degreeC or more, Preferably it is 195 degrees C or less, More preferably, it is 190 degrees C or less, More preferably, it is 185 degrees C or less, Most preferably, it is 180 degrees C or less. If the IBP is less than the lower limit, a part of the light fraction is vaporized, and the amount of unburned hydrocarbons in the exhaust gas increases with a wide spray range in the engine of the diesel vehicle. As a result, the startability at high temperatures and the rotational stability of the engine at idling tend to decrease. On the other hand, when IBP exceeds the upper limit value, the startability and drivability at low temperatures in a diesel vehicle tend to be reduced.

  Further, the 10% distillation temperature (hereinafter abbreviated as “T10”) of the light oil composition of the present invention is preferably 165 ° C. or higher, more preferably 170 ° C. or higher, still more preferably 175 ° C. or higher, and particularly preferably 180 ° C. It is preferably 205 ° C. or lower, more preferably 200 ° C. or lower, still more preferably 195 ° C. or lower, and particularly preferably 190 ° C. or lower. When T10 is less than the lower limit, a part of the light fraction is vaporized, and the amount of hydrocarbons in the exhaust gas increases as the spray range becomes wide in the engine of the diesel vehicle. As a result, the startability at high temperatures and the rotational stability of the engine at idling tend to decrease. On the other hand, when T10 exceeds the upper limit, the startability and drivability at low temperatures in a diesel vehicle tend to be reduced.

  The 50% distillation temperature (hereinafter abbreviated as “T50”) of the light oil composition of the present invention is preferably 200 ° C. or higher, more preferably 205 ° C. or higher, still more preferably 210 ° C. or higher, particularly preferably 215. Also, it is preferably 260 ° C. or lower, more preferably 255 ° C. or lower, still more preferably 250 ° C. or lower, and particularly preferably 245 ° C. or lower. When T50 is less than the lower limit value, the fuel consumption rate, engine output, startability at high temperatures, and engine rotation stability at idling tend to decrease in a diesel vehicle. On the other hand, when T50 exceeds the upper limit, particulate matter (hereinafter referred to as PM) discharged from the engine in a diesel vehicle tends to increase.

  The 90% distillation temperature (hereinafter abbreviated as “T90”) of the light oil composition of the present invention is preferably 265 ° C. or higher, more preferably 270 ° C. or higher, still more preferably 275 ° C. or higher, particularly preferably 280. It is preferably at least 335 ° C, more preferably at most 330 ° C, even more preferably at most 325 ° C, particularly preferably at most 320 ° C. If T90 is less than the lower limit, the fuel consumption rate, startability at high temperatures, and stability of engine rotation at idling tend to decrease in a diesel vehicle. Moreover, when the light oil composition contains a low temperature fluidity improver, the improvement effect such as a clogging point due to the low temperature fluidity improver tends to be lowered. On the other hand, when T90 exceeds the upper limit, PM discharged from the engine in a diesel vehicle tends to increase.

  The end point (hereinafter abbreviated as “EP”) of the light oil composition of the present invention is preferably 310 ° C. or higher, more preferably 315 ° C. or higher, further preferably 320 ° C. or higher, particularly preferably 325 ° C. or higher. Also, it is preferably 355 ° C. or lower, more preferably 350 ° C. or lower, further preferably 345 ° C. or lower, and particularly preferably 340 ° C. or lower. If EP is less than the lower limit value, the fuel consumption rate in diesel vehicles, startability at high temperatures, and stability of engine rotation at idling tend to decrease. Moreover, when the light oil composition contains a low temperature fluidity improver, the improvement effect such as a clogging point due to the low temperature fluidity improver tends to be lowered. On the other hand, when EP exceeds the upper limit, PM discharged from the engine in a diesel vehicle tends to increase.

  In the present invention, “IBP”, “T10”, “T50”, “T90” and “EP” are measured in accordance with JIS K 2254 “Petroleum products—Distillation test method—Atmospheric pressure method”, respectively. Means value.

  Further, regarding the lubricity of the light oil composition of the present invention, the WS1.4 value of HFRR is preferably 500 or less, more preferably 460 or less, still more preferably 420 or less, and particularly preferably 400 or less. When the WS1.4 value satisfies the above conditions, the lubricity in the injection pump in the diesel vehicle can be sufficiently ensured. The “HFRR WS1.4 value” referred to in the present invention is an index for determining the lubricity of light oil, and is the Petroleum Institute Standard JPI-5S-50-98 “Light Oil-Lubrication” issued by the Japan Petroleum Institute. It means a value measured in accordance with the “Testing Method”.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example at all.

[Examples 1-2, Comparative Examples 1-3]
In Examples 1-2 and Comparative Examples 1-3, a light oil composition having the composition and properties shown in Table 1 was prepared. Each of the light oil compositions of Examples 1 and 2 is a fuel obtained by obtaining a wax and a middle distillate from natural gas by a Fischer-Tropsch reaction and subjecting them to a hydrotreatment. The light oil composition of Comparative Example 1 is a fuel obtained by obtaining wax and middle distillate from natural gas by the Fischer-Tropsch reaction and subjecting it to hydrogenation treatment. The light oil composition of Examples 1 and 2 This is a fuel with a lower degree of hydrotreating than The diesel oil composition of Comparative Example 2 is a fuel obtained by further hydrotreating a crude oil-derived fuel produced by general hydrorefining to further reduce sulfur and aroma. The diesel oil composition of Comparative Example 3 is a crude oil-derived fuel produced by general hydrorefining.

  Next, the following test was implemented about each light oil composition of Examples 1-2 and Comparative Examples 1-3.

[Ignition test]
In order to confirm the ignitability at low temperature, white smoke at low temperature was measured on a chassis dynamometer capable of controlling the environmental temperature using the following diesel engineer.
(Vehicle specifications)
Engine type: Supercharged inline 4-cylinder diesel compression ratio with intercooler: 18.5
Maximum output: 125kW / 3400rpm
Maximum torque: 350Nm / 2400rpm
Regulatory compliance: Fiscal 1997 exhaust gas regulatory compliance mission: 4AT
Exhaust gas aftertreatment device: oxidation catalyst.

  In the low-temperature actual vehicle test, first, a fuel system of a diesel vehicle was flushed with an evaluation fuel (each light oil composition) at room temperature. After the flashing fuel was extracted and the main filter was replaced with a new one, a prescribed amount of evaluation fuel (1/2 of the fuel tank capacity of the test vehicle) was applied to the fuel tank. Thereafter, the ambient temperature is rapidly cooled from room temperature to 5 ° C., held at 5 ° C. for 1 hour, gradually cooled to reach −10 ° C. at a cooling rate of 1 ° C./h, and held at −10 ° C. for 1 hour. A running test was started. Measurement was impossible if the engine did not start even after 10 seconds of cranking were repeated twice at 30 second intervals. When the engine could be started, it was left for 30 seconds by idling, and then the operation of depressing the accelerator pedal to the full for 5 seconds was repeated 5 times, and the amount of white smoke at that time was measured with a transmission type measuring instrument. For each light oil composition, the average value of 5 times was calculated, and the relative value when the average value of Comparative Example 3 was taken as 100 was determined to evaluate the ignitability. The obtained results are shown in Table 1.

[Low-temperature vehicle test]
On a chassis dynamometer capable of controlling the environmental temperature, a low-temperature actual vehicle test was conducted using the following two diesel vehicles A and B.
(Vehicle A specifications)
Maximum loading capacity: 2t
Engine type: Total displacement of inline 4-cylinder diesel engine: 4.3L
Fuel injection pump: Row type conformity standard: Short-term exhaust gas regulation conformity (base vehicle)
Exhaust gas aftertreatment device: PM reduction device designated by Tokyo (conforming to Category 4)
Fuel used for PM reduction device: Low sulfur gas oil (sulfur content 50 mass ppm or less).
(Vehicle B specifications)
Engine type: Total displacement of supercharged inline 4-cylinder diesel engine with intercooler: 3.0L
Fuel injection system: Common rail method Applicable standard: Long-term exhaust gas regulation compliant exhaust aftertreatment device: Oxidation catalyst.

  In the low-temperature actual vehicle test, first, a fuel system of a diesel vehicle was flushed with an evaluation fuel (each light oil composition) at room temperature. After the flushing fuel was extracted and the main filter was replaced with a new one, a prescribed amount of evaluation fuel (1/2 of the fuel tank capacity of the test vehicle) was applied to the fuel tank. Thereafter, the ambient temperature is rapidly cooled from room temperature to 5 ° C., held at 5 ° C. for 1 hour, gradually cooled to reach −10 ° C. at a cooling rate of 1 ° C./h, and held at −10 ° C. for 1 hour. A running test was started. The running test was composed of “engine start”, “5 minutes idling”, “acceleration to 50 km / h” and “running for 1 hour at 50 km / h”, and the pass / fail was determined by the operating condition of the winding. Specifically, the case where there was no problem in engine starting, idling and acceleration and the traveling at 50 km / h could be maintained over the previous traveling was judged as good (◎). Also, if the engine could not be started at the first cranking, or if the vehicle speed decreased temporarily during driving but then recovered, minor problems occurred, but it was possible to continue driving ( ○). In addition, it was determined that the vehicle could not be started due to the inability to start (the engine could not be started even if cranking for 10 seconds was repeated 5 times at 30-second intervals), and the vehicle could not be maintained due to idling stall or engine stop. The obtained results are shown in Table 1.

It is a graph which shows an example of the correlation with the retention time and intensity | strength of the gas chromatography of the component with the same carbon number obtained using GC-TOFMS.

Claims (3)

In the range of 10 to 21 carbon atoms, the molar ratio (m is an integer of 10 to 21) of the isoparaffins having 2 or more carbon atoms to 1 branched isoparaffins having 5 to 5 carbon atoms is 0.05 to 3.5. And,
In the range of 22 to 25 carbon atoms, the molar ratio (n is an integer of 22 to 25) of n-branch or more isoparaffins of carbon number n to 0.1 branch is 0.1 to 10.0. A gas oil composition characterized by the above.   The light oil composition according to claim 1, wherein the cloud point is 0 ° C or lower and the pour point is -7.5 ° C or lower. The cetane number is 65 or more, the sulfur content is 10 mass ppm or less, the aromatic content is 1 mass% or less, the naphthene content is 5 mass% or less, and the clogging point is The gas oil composition according to claim 1 or 2, wherein the gas oil composition is -5 ° C or lower.

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