JP5106057B2 - Light oil composition - Google Patents

Description

  The present invention relates to a light oil composition, and particularly to a light oil composition having a very low sulfur content.

  Light oil used for diesel engine fuel, etc. is discolored when oxidized, the formation of precipitated polymer (sludge), increased viscosity, etc. Also, the peroxide generated by oxidation (peroxide) is the fuel system It is known to deteriorate members (rubber, metal, etc.). Therefore, oxidation stability is one of the important indices for evaluating the quality stability of light oil, and a light oil having high oxidation stability is desired. In recent years, diesel engines have been required to increase the heat load on light oil as the pressure of fuel injection by the common rail further increases due to stricter exhaust gas regulations, and to improve the oxidation stability of light oil more than before.

  In addition, so-called sulfur-free fuel oil, which has almost no sulfur content to prevent poisoning of the exhaust gas purification catalyst, has been put on the market since January 2005. In addition, against the background of fuel efficiency regulations, carbon dioxide emission reduction, and reduction of environmentally hazardous substances in exhaust gas, the sulfur content of light oil is required to be further reduced from 10 ppm by mass. In order to remove the sulfur content, hydrodesulfurization treatment is generally performed in which hydrogen is blown into light oil at high temperature and pressure and brought into contact with a solid catalyst to remove the sulfur content as hydrogen sulfide by hydrocracking reaction. However, when subjected to a heat load at a high temperature in the process of highly removing sulfur, unstable substances are likely to be generated in light oil, and oxidation stability often deteriorates.

  Therefore, it is conceivable to lower the temperature in the reaction to remove the sulfur content of the gas oil to suppress the production of substances having a hydrocarbon structure unstable to oxygen, but the catalytic activity of hydrodesulfurization will be reduced. It is difficult to remove the sulfur content, and nitrogen-containing compounds such as indoles, which are generally contained in catalytically cracked diesel oil and pyrolysis diesel oil, which are generally used in feedstock oil, tend to remain in the product after hydrodesulfurization. Deteriorates oxidation stability.

Therefore, in order to improve the oxidation stability of light oil, various amine-based and phenol-based antioxidants have been added to light oil for a long time. JP, 2004-225000, A (patent documents 1) is mentioned as an example which added antioxidant to light oil which reduced sulfur content to 10 mass ppm or less. Here, N, N′-diisopropyl p-phenylenediamine or the like can be used as an amine-based antioxidant, and 2,6-di-tert-butyl-4-methylphenol or the like can be used as a phenol-based antioxidant. Are listed.
However, the demand for oxidation stability for diesel oil has increased due to an increase in the thermal load on diesel oil, especially with the high-pressure injection of diesel engines. Accordingly, the oxidation stability evaluation test temperature has also increased. The amount of the antioxidant necessary to obtain the desired effect increases as the light oil composition with poor oxidation stability increases the production cost. Furthermore, as the amount of the antioxidant increases, the antioxidant is likely to precipitate due to the temperature decrease. On the other hand, if the additive amount is small, after the antioxidant effect of the additive is exhausted during oxidation, the oxidation stability of the light oil will deteriorate significantly, causing adverse effects such as engine cleanliness and corrosion of metal materials. Effect.

Therefore, it has been proposed to maintain the oxidation stability of light oil without adding an antioxidant additive (Patent Document 2). Specifically, we focus on fluorenes and naphthenebenzenes as substances with poor oxidation stability, and balance these contents with the contents of naphthalene, which is a substance with good oxidation stability, to achieve a specific range. Has obtained oxidation stability.
JP 2004-225000 A JP 2006-137922 A

According to the research of the present inventor, even when the content of fluorenes, naphthenebenzenes and naphthalenes is in a specific range as in the invention described in Patent Document 2, sufficient oxidation stability may not be exhibited. As a result, it was predicted that components other than the above components significantly affect the oxidative stability.
Then, this invention makes it a subject to identify the other substance which influences the oxidation stability of light oil notably, and to provide the low sulfur light oil composition which controlled content of the substance to the specific range.

The present inventor has intensively studied to solve the above problems, and has come to focus on unsaturated compounds in light oil. As a result, styrenes whose deterioration in oxidation stability is contained in a trace amount in raw material oil (or base material). And dienes, or the formation of trace amounts of styrenes and dienes and the reduction of trace amounts of naphthalenes that occur in the process of highly reducing the sulfur content in light oil. Among the styrenes, styrene compounds having 10 or less carbon atoms are found, and among the dienes, particularly diene compounds having 15 or more carbon atoms, and these compounds are oxidative stability of light oil. It was confirmed that the oxidation stability of light oil could be improved by controlling the content of these compounds.
In addition, condensed polycyclic aromatic hydrocarbons, especially bicyclic and tricyclic condensed polycyclic aromatic hydrocarbons, have the effect of stabilizing active species generated during the oxidation process of light oil, so they are oxidized by dienes and styrenes. It has been found that it is possible to neutralize the adverse effects of stability, and by limiting the amount of styrenes, dienes, and condensed polycyclic aromatic hydrocarbons within a specific range, deterioration of oxidation stability can be suppressed. It was.

That is, in one aspect of the present invention, the content of styrene compounds having a sulfur content of 10 ppm or less and a carbon number of 10 or less is 0.15% by mass or less and the content of a diene compound having 15 or more carbons is total. It is a gas oil composition which is 0.73 mass% or more and 2.00 mass% or less, and whose oxidation index IO represented by following Formula is 0.5 or less.
IO = (C10LST) + 3 × (C17HDI) − (R2A) −5 × (R3A)
(C10LST: C10 or less styrene compound content, mass%, C17HDI: Diene compound content of 17 or more carbon atoms, mass%, R2A: Bicyclic compound contained in condensed polycyclic aromatic hydrocarbons Amount, mass%, R3A: tricyclic compound content in condensed polycyclic aromatic hydrocarbon, mass%)

  In one embodiment, the light oil composition according to the present invention has a total content of styrene compounds having 10 or less carbon atoms of 0.10% by mass or less.

  In one embodiment, the light oil composition according to the present invention has a total content of bicyclic and tricyclic condensed polycyclic aromatic hydrocarbons of 0.10% by mass or more.

  In one embodiment, the light oil composition according to the present invention has a total content of diene compounds having 17 or more carbon atoms of 1.00% by mass or less.

According to the light oil composition of the present invention, the oxidation stability-inhibiting substance in light oil, which has not been studied in the past, is controlled, so that the oxidation stability of light oil can be improved.
More specific effects include the effect of reducing oxidation polymer due to thermal load received by high pressure injection during storage and diesel engines, and as a result, the amount of antioxidant used for these improvements is reduced. Further, since it can be eliminated, the manufacturing cost can be reduced.

Sulfur content The light oil composition according to the present invention has a sulfur content of 10 ppm by mass or less. Since the sulfur content is 10 mass ppm or less, malodor and environmental load due to sulfurous acid gas and the like generated by combustion are reduced. The sulfur content is preferably 5 ppm by mass or less, more preferably 1 ppm by mass or less, from the viewpoint of an environmental additive and fuel consumption reduction.

In general, a wide variety of components are mixed in a styrene gas oil composition, and even if only styrenes are taken up, there are various types of types, but the present inventor is included in light oil. It has been found that most or all of the styrenes have 10 or less carbon atoms.
Even a styrene compound having 11 or more carbon atoms may have an adverse effect on oxidation stability, but it is usually not detected in a light oil composition and is an amount that can be ignored even if detected.
Therefore, regarding the effect on the oxidation stability by styrenes, the oxidation stability in the light oil composition can be evaluated by tracking only the content of styrenes having 10 or less carbon atoms. By controlling the styrenes, the oxidation stability of the light oil composition can be improved.
Based on the above knowledge, in one embodiment, the light oil composition according to the present invention has a total content of styrene compounds having 10 or less carbon atoms of 0.15% by mass or less, and is preferably from the standpoint of improvement in oxidation stability. It is 10 mass% or less, More preferably, it is 0.08 mass% or less, More preferably, it is 0.05 mass% or less, Most preferably, it is 0.01 mass% or less.

Specific examples of the styrene compound having 10 or less carbon atoms found in the light oil composition include styrene, methylstyrene, dimethylstyrene, and the like, and dimethylstyrene is mainly contained in the light oil.
Therefore, in further progress, with regard to styrenes, it is possible to evaluate the oxidative stability in a light oil composition by following only the content of dimethyl styrene, typically 2,4-dimethyl styrene. Typically, the oxidation stability of the light oil composition can be improved by controlling the content of 2,4-dimethylstyrene.
Accordingly, in a typical embodiment, the light oil composition according to the present invention preferably has a total content of dimethylstyrene of 0.15% by mass or less, more preferably 0.10% by mass or less, and still more preferably 0. 0.08% by mass or less, particularly preferably 0.05% by mass or less, and most preferably 0.01% by mass or less. In a more typical embodiment, the total content of 2,4-dimethylstyrene is 0.00. 15 mass% or less is preferable, More preferably, it is 0.10 mass% or less, More preferably, it is 0.08 mass% or less, Especially preferably, it is 0.05 mass% or less, Most preferably, it is 0.01 mass% or less.

Dienes As mentioned above, since various components are generally mixed in the light oil composition, even if it is a diene, it is considered that various types are also mixed. However, according to the research results of the present inventors, most of the dienes contained in light oil are those having 15 or more carbon atoms, and from the content changes before and after the oxidation treatment of light oil, 17 or more carbon atoms. These diene compounds are rich in oxidation reactivity, and those having 17 or more carbon atoms are considered to have a particularly bad influence on oxidation stability. Even dienes having 14 or less carbon atoms may adversely affect oxidation stability, but they are not usually detected in light oil compositions, and even if detected, they are negligible amounts.
Therefore, regarding the effect of dienes on the oxidation stability, the oxidation stability in the light oil composition can be improved by tracking only the content of dienes having 15 or more carbon atoms, and also only dienes having 17 or more carbon atoms. The oxidation stability of the light oil composition can be improved by controlling dienes having 15 or more carbon atoms, and further 17 or more carbon atoms.
Based on the above findings, in one embodiment, the light oil composition according to the present invention has a total content of diene compounds having 15 or more carbon atoms of 2.00% by mass or less, preferably 1.50% by mass because of improved oxidation stability. % Or less, more preferably 1.00% by mass or less, and particularly 0.80% by mass or less.
In another embodiment of the light oil composition according to the present invention, the total content of diene compounds having 17 or more carbon atoms is 1.00% by mass or less, preferably 0.80% by mass or less from the viewpoint of improving oxidation stability. More preferably, it is 0.50% by mass or less, particularly 0.10% by mass or less. In addition, since the dienes having 17 or more carbon atoms found in the light oil composition mainly have 17 to 20 carbon atoms, and more typically 17 and 18 carbon atoms, the light oil composition according to the present invention is still another one. In the embodiment, the total content of diene compounds having 17 to 20 carbon atoms is 1.00% by mass or less, preferably 0.80% by mass or less, more preferably 0.50% by mass or less, particularly preferably 0.50% by mass or less. Is typically 1.00% by mass or less, preferably from 0.80% by mass or less, more preferably 0.80% by mass or less, and more preferably 0.80% by mass or less. Is 0.50% by mass or less, particularly 0.10% by mass or less.

It is mainly found in gas oil compositions as diene compounds having 15 or more carbon atoms, Himakara-2,4-diene (C ₁₅ H ₂₄ ), octadecadiene (eg, bicyclo [10.6.0] octadeca- 1 (12), 15-diene (C ₁₈ H ₃₀ )) and tetramethyl-phenylbicycloheptadiene (eg, 1,5,6,7-tetramethyl-3-phenylbicyclo [3.2.0] hepta -2,6-dienes (C ₁₇ H ₂₀ )) and the like, in particular, dienes having a bicyclo structure of 17 or more carbon atoms, typically 17 to 20 carbon atoms, more typically 17 and 18 carbon atoms. Is often found. Therefore, to go further, with respect to dienes, only the content of dienes having a bicyclo structure of 17 or more carbon atoms, typically 17 to 20 carbon atoms, more typically 17 and 18 carbon atoms is traced. In particular, the oxidation stability in the light oil composition can be evaluated, and the oxidation stability of the light oil composition can be improved by controlling the content of the diene having such a bicyclo structure.
Accordingly, the gas oil composition according to the present invention, in a more typical embodiment, has 17 or more carbon atoms having a bicyclo structure, typically 17 to 20 carbon atoms, more typically 17 and 18 carbon atoms. The total content of dienes is 1.00% by mass or less, preferably 0.80% by mass or less, more preferably 0.50% by mass or less, and particularly 0.10% by mass or less, from the viewpoint of improving oxidation stability.

Condensed polycyclic aromatic hydrocarbons Condensed polycyclic aromatic hydrocarbons have the effect of stabilizing the active species generated during the oxidation of light oil, and thus neutralize the negative effects of oxidation stability caused by dienes and styrenes. it can. In particular, since condensed polycyclic aromatic hydrocarbons of 2 and 3 rings have a large effect, with regard to the condensed polycyclic aromatic hydrocarbons, it is possible to trace only the condensed polycyclic aromatic hydrocarbons of 2 and 3 rings. The oxidation stability in the light oil composition can be evaluated, and the oxidation stability of the light oil composition can be improved by increasing the bicyclic and tricyclic condensed polycyclic aromatic hydrocarbons. In the present invention, the bicyclic and tricyclic condensed polycyclic aromatic hydrocarbons refer to hydrocarbons having one naphthalene ring, anthracene ring, phenanthrene ring, or phenalene ring in the molecule. However, since a molecule having a condensed or non-condensed saturated ring (eg, tetralin ring, cycloalkane ring) in the molecule (eg, 9,10-dihydroanthracene) does not contribute much to the improvement of oxidation stability, Even if it has an anthracene ring or a phenanthrene ring, it is excluded from the bicyclic and tricyclic condensed polycyclic aromatic hydrocarbons.

Therefore, in one embodiment, the light oil composition according to the present invention has a total content of bicyclic and tricyclic condensed polycyclic aromatic hydrocarbons of 0.10% by mass or more, preferably 0.40 from the viewpoint of improving oxidation stability. % By mass or more, more preferably 0.70% by mass or more, particularly 0.90% by mass or more.
However, if the content of the polycyclic aromatic hydrocarbon compound is too large, the combustibility deteriorates this time, and the amount of nitrogen oxides and particulate matter in diesel vehicle exhaust gas increases, so the total content is preferably 3.5. It is at most 3.0% by mass, more preferably at most 2.5% by mass, particularly preferably at most 2.0% by mass.

  Furthermore, among the condensed polycyclic aromatic hydrocarbons of 2 and 3 rings, the effect of oxidative stability is that the number of alkyl substituents in the side chain is 0 to 2, so the light oil according to the present invention In a preferred embodiment of the composition, the total content of bicyclic and tricyclic condensed polycyclic aromatic hydrocarbons having 0 to 2 alkyl substituents in the side chain is 0.10% by mass or more in total. From the viewpoint of stability improvement, it is preferably 0.40% by mass or more, more preferably 0.70% by mass or more, and particularly 0.90% by mass or more. Further, for the same reason as above, the total is preferably 3.0% by mass or less, more preferably 2.5% by mass or less, and particularly 2.0% by mass or less.

Among condensed polycyclic aromatic hydrocarbons, typical examples of bicyclic compounds are naphthalene and naphthalene having an alkyl substituent in the side chain. As a compound mainly contained in light oil, Naphthalene having a number of 0, 1-methylnaphthalene, 2- (1-methylethyl) naphthalene having a number of side chain alkyl substituents of 1, 2,6- Dimethylnaphthalene, 1,7-dimethylnaphthalene, 2-methyl-1-propylnaphthalene, 2,3,5-trimethylnaphthalene, 1,4,6-trimethylnaphthalene having 2, 3 side chain alkyl substituents, , 3,6-trimethylnaphthalene, 1,2,3,4-tetramethylnaphthalene having 4 side chain alkyl substituents, and the like.
In addition, typical examples of tricyclic compounds among condensed polycyclic aromatic hydrocarbons include anthracene, phenanthrene, anthracene having an alkyl substituent in the side chain, and alkyl-substituted phenanthrene, which are mainly contained in light oil. Most of the anthracene compounds are hydrogenated, and among the condensed polycyclic aromatic hydrocarbons mainly contained in light oil, tricyclic compounds are phenanthrenes with 0 side chain alkyl substituents as well as alkyls. Phenanthrene having a substituent in the side chain, for example, 2,5-dimethylphenanthrene having 2 side chain alkyl substituents, 2,3,5-trimethyl having 3 side chain alkyl substituents Phenanthrene is detected by a gas chromatograph.

  Among these condensed polycyclic aromatic hydrocarbons, the bicyclic and tricyclic substances have different oxidation reaction rates depending on the number of rings, the number of side chains, and the chemical structure, and due to differences in hydrotreating conditions and boiling points, A content of 0.01% by mass or more, preferably 0.05% by mass or more, particularly preferably 0.10% by mass or more is preferable because the content in the light oil is different. Further, as described above, from the viewpoint of increasing the amount of nitrogen oxides and particulate matter in diesel vehicle exhaust gas, each content is 0.20% by mass or less, preferably 0.18% by mass or less, particularly 0.15% by mass. % Or less is preferable.

Oxidation index Based on the results of various experiments, the present inventor has found that styrenes having 10 or less carbon atoms and dienes having 17 or more carbon atoms have an adverse effect on the oxidation stability of gas oil compositions, and that polycyclic and tricyclic condensed polymers. It has been found that the magnitude relationship with the effect of improving the oxidative stability by cyclic aromatic hydrocarbons can be generally expressed by the following formula, whereby the oxidative stability of the light oil composition can be more quantitatively evaluated.
IO (oxidation index) = (C10LST) + 3 x (C17HDI)-(R2A)-5 x (R3A)
(C10LST: C10 or less styrene compound content, mass%, C17HDI: Diene compound content of 17 or more carbon atoms, mass%, R2A: Bicyclic compound contained in condensed polycyclic aromatic hydrocarbons Amount, mass%, R3A: tricyclic compound content in condensed polycyclic aromatic hydrocarbon, mass%)
The light oil composition according to the present invention has an oxidation index IO of 0.5 or less, preferably 0.0 or less, more preferably −0.5 or less, particularly −1.0 or less in view of improvement in oxidation stability. However, if the oxidation index IO is too low, deterioration in combustibility due to the presence of the condensed polycyclic aromatic hydrocarbon is seen, so the oxidation index IO is preferably −5.0 or more, more preferably −3.0 or more, In particular, it is -2.0 or more.

  About each said component, the content can be measured by the gas chromatography mentioned later.

  To the light oil composition according to the present invention, any antioxidant known to those skilled in the art may be added as necessary. A person skilled in the art can appropriately adjust the addition amount in the case of adding the antioxidant according to the target oxidation stability. For example, styrenes having 10 or more carbon atoms and dienes having 15 or more carbon atoms can be used. In an amount of 0.01% by mass or more, it is also effective to add an antioxidant in order to maintain oxidation stability. For example, the addition amount is 1 to 10 ppm by mass, and 10 ppm by mass or more. It is good.

  The antioxidant can be used without particular limitation among phenols and amines. For example, 2,6-di-t-butylphenol, 2,6-di-t-butyl-4-methylphenol, 2,4 -Phenolic antioxidants such as dimethyl-6-t-butylphenol, 2,4,6-tri-t-butylphenol, 2-t-butyl-4,6-dimethylphenol, 2-t-butylphenol, N, Examples thereof include amine-based antioxidants such as N′-diisopropyl-p-phenylenediamine and N, N′-di-sec-butyl-p-phenylenediamine, and mixtures thereof. In addition to phenolic and amine compounds, substances with an antioxidative effect are conceivable, but for the sake of clarity, in the present invention, only phenolic and amine compounds are treated as antioxidants to prevent oxidation. When other compounds having an effect are added, they are handled as a light oil base.

  In addition, known fuel additives such as a low-temperature fluidity improver, an abrasion resistance improver, and a cetane number improver may be added. An ethylene copolymer or the like can be used as the low-temperature fluidity improver, and vinyl esters of saturated fatty acids such as vinyl acetate, vinyl propionate and vinyl butyrate are particularly preferably used. As the wear resistance improver, for example, long chain fatty acids (carbon number 12 to 24) or fatty acid esters thereof are preferably used. The wear resistance is sufficiently improved by the addition amount of 10 to 500 ppm, preferably 50 to 100 ppm.

  The gas oil composition of the present invention is a gas oil fraction obtained from, for example, an atmospheric distillation apparatus, a catalytic cracking apparatus, a thermal cracking apparatus or the like as a raw material oil, that is, a fraction distilled at a boiling point of 140 to 400 ° C. Raw material that is obtained by hydrodesulfurization, but does not contain a large amount of these compounds in the hydrodesulfurization feedstock in order to suppress the content of styrene compounds and diene compounds that adversely affect oxidation stability It is effective to suppress the mixing ratio of oil, for example, oil obtained by pyrolyzing asphalt, or to select a raw material oil. In order to suppress the formation of these compounds, it is also effective to lower the reaction temperature, increase the hydrogen partial pressure, or increase the hydrogen / oil ratio. It should be noted that by increasing the hydrogen partial pressure or increasing the hydrogen / oil ratio, the content of condensed polycyclic aromatic hydrocarbons having an effect of improving oxidation stability is reduced. In order to increase the ring content, styrene compounds such as catalytic cracking gas oil containing a large amount of these condensed polycyclic aromatic components and heavy fractions with relatively low content of diene compounds are used in the feedstock. Mixing is also effective. In addition, since these base materials also contain many difficult desulfurization components, it is necessary to use a catalyst that selectively removes sulfur in hydrodesulfurization. It is also effective to mix a base material containing a large amount of condensed polycyclic aromatics and low sulfur content after light oil hydrodesulfurization. Examples of the substrate include components having 11 or more carbon atoms distilled from the catalytic reformer.

The hydrodesulfurization uses one or more of Co, Mo and Ni as a hydrodesulfurization catalyst, and optionally carries P, and the reaction temperature is 270 to 380 ° C., preferably 295 to 360 ° C., Reaction pressure 2.5 to 8.5 MPa, preferably 2.7 to 7.0 MPa, LHSV 0.9 to 6.0 h ⁻¹ , preferably 0.9 to 5.4 h ⁻¹ , hydrogen / oil ratio 130 to 300 ( Fluctuations of about ± 5 are permissible.) Appropriate selection is made within the range of Nm ³ / kL so that the above-described light oil composition of the present invention can be obtained. In particular, the LHSV, the hydrogen partial pressure, and the hydrogen / oil ratio are preferably large, but if it is too large, the condensed polycyclic aromatic component is hydrogenated, so that the allowable upper limit is not exceeded. The reaction temperature is preferably lowered in order to suppress the formation of styrene compounds and diene compounds having poor oxidation stability.
The light oil composition obtained by the above method is a kerosene composition having good oxidation stability to improve low-temperature fluidity, and distillate oil from a catalytic reformer containing a large amount of condensed polycyclic aromatics. And a component having 11 or more carbon atoms can be mixed at an appropriate ratio.

  The light oil composition of the present invention will be specifically described with reference to examples. In addition, although this invention is realizable if it implements like the following examples, it is not limited to a present Example.

The physical properties used in the present invention are measured by the following methods.
1) Density: The method specified in JIS K2249 “Crude oil and petroleum product density test method”.
2) Flash point: Tag sealed flash point test method specified in JIS K2265 “Crude oil and petroleum product flash point test method”.
3) Distillation property: A method defined in JIS K2254 “Distillation test method”.
4) Sulfur content: A method defined in JIS K2541-6 “Sulfur content test method (ultraviolet fluorescence method)”.
5) Aromatic content: The method specified in JPI-5S-49-97 “Petroleum products—Hydrocarbon type test method—High performance liquid chromatograph method”.
6) Total acid value: The number of milligrams of potassium hydroxide required to neutralize all acidic components contained in 1 g of a sample according to the method defined in JIS K2276 “Test method for aviation fuel oil”.
7) Cetane index: A method defined in JIS K2280 “Petroleum products—fuel oil—octane number and cetane number test method and cetane index calculation method”.
8) Component: Two gas chromatography columns having different polarities were measured using gas chromatography connected in series via a modulator. Detailed conditions are as follows.
GC system: After passing through the primary column, mass transfer control is performed by the modulator, and then the secondary column is passed through and separation is performed based on the difference in polarity. The analyzer system configuration includes an HP-6890N type FID detector GC manufactured by Agilent Technologies and an AccuTOF JMS-T100GC time-of-flight mass spectrometer manufactured by JEOL.
Primary column: nonpolar or slightly polar column (for example, PTE-5 manufactured by Supelco, length 30 m, inner diameter 0.25 mm, film thickness 0.25 μm)
Modulator hollow column: length 2m, inner diameter 0.1mm
Secondary column: High polarity column (for example, SpelcoWAX10 manufactured by Supelco, length 2 m, inner diameter 0.25 mm, film thickness 0.25 μm)
Temperature rising conditions: 50 ° C. (5 minutes hold) to 280 ° C. (27 minutes hold) at 10 ° C./minute Inlet temperature: 280 ° C.
Injection volume: 1.0 μl
Split ratio: 100: 1
Carrier gas: He, 1.0 ml / min Modulator temperature: The following cold temperature and hot temperature are repeated.
Hot jet gas temperature: 150 ° C. (5 min hold) to 320 ° C. (33 min hold) at 10 ° C./min Cold jet gas temperature: about −140 ° C.
Modulator frequency: 0.3 seconds hot temperature for 6 seconds, then cold temperature for 5.7 seconds Interface hollow column: 0.5 m length, 0.25 mm inner diameter
FID gas conditions: hydrogen (45 mL / min), air (450 mL / min), make-up helium (25 mL / min, constant)

Preparation of gas oil composition Test gas oil 1: A fraction having a boiling range of 140 to 370 ° C distilled from an atmospheric distillation apparatus was used with a commercial catalyst supporting Co, Mo, P, reaction temperature 350 ° C, reaction pressure 7 It was obtained by hydrorefining under the conditions of 0.2 MPa, hydrogen / oil ratio 300 ± 5 Nm ³ / kL, LHSV 1.0 h ⁻¹ , hydrogen purity 94%.
Test gas oil 2: 70% by volume of a fraction having a boiling range of 140 to 370 ° C. distilled from an atmospheric distillation apparatus and 30% by volume of a fraction having a boiling range of 140 to 370 ° C. from an asphalt pyrolysis apparatus, Ni, Hydrogenation purification using commercially available catalyst carrying Mo and P under conditions of reaction temperature 335 ° C., reaction pressure 6.9 MPa, hydrogen / oil ratio 250 ± 5 Nm ³ / kL, LHSV 1.2 h ⁻¹ , hydrogen purity 95% I got it.

Test gas oil 3: 90% by volume of a fraction having a boiling range of 140 to 370 ° C. distilled from an atmospheric distillation apparatus and 10% by volume of a fraction having a boiling range of 140 to 370 ° C. distilled from a catalytic cracker , Using a commercially available catalyst supporting P, hydrorefined under the conditions of a reaction temperature of 336 ° C., a reaction pressure of 7.2 MPa, a hydrogen / oil ratio of 300 ± 5 Nm ³ / kL, LHSV of 1.0 h ⁻¹ , and a hydrogen purity of 94%. I got it.
Table 3 shows the properties of each sample gas oil 1 to 3 prepared above.

Additive DMN: 94% purity dimethylnaphthalene manufactured by Kanto Chemical Co., Inc. was used.
AC11: A component having 11 or more carbon atoms in a gasoline which has been subjected to catalytic reforming at a reaction temperature of 500 ° C. and a reaction pressure of 1.0 MPa using a hydrodesulfurized naphtha as a raw material after distillation separation in an atmospheric distillation apparatus, It was obtained by precision distillation separation so that the content was 0.10% by volume or less.
TMBz: 1,2,4-trimethylbenzene with a purity of 97% or more and a deer grade grade manufactured by Kanto Chemical Co., Ltd. was used.
C12O: 1-dodecene of Kanto Chemical Co., Ltd. purity 97% or more deer grade 1 grade was used.
Styrene: Deer grade 1 grade styrene with a purity of 99% or more manufactured by Kanto Chemical Co., Ltd. was used.
Using these, according to the oxidation stability test method of the quality assurance method applied to the BDF mixed gas oil, 300 mL of each test gas oil was put in a pressure vessel and oxygen was blown at 3 L / hr in a constant temperature bath at 115 ° C. The gas oil was forcibly deteriorated by holding for a time. Then, it took out from the thermostat, cooled to room temperature, and measured the total acid value before and behind deterioration by said method. The results are shown in Tables 2 and 3.
Table 1 shows the results of measuring the components before and after oxidation of the test light oil 1.

  From Table 1, diene compounds with particularly poor oxidation stability are reduced during the oxidation treatment, while bicyclic aromatic compounds are consumed in the condensed polycyclic aromatic hydrocarbons with good oxidation stability. I understand. In addition, the olefin compounds and naphthenebenzene compounds were reduced by the oxidation treatment, and monocyclic aromatic compounds were also consumed. Although these compounds are thought to have a considerable influence on the oxidation reaction, Table 2 shows that the oxidative stability effects of olefin compounds and monocyclic aromatic compounds are small compared to styrene compounds, and naphthenebenzene. It can be seen that tetralin, a similar compound, has the effect of improving oxidative stability, but not as much as in the examples. Table 3 shows that Examples 1 to 3 have little increase in the total acid value before and after the oxidation treatment and good oxidation stability with respect to Comparative Examples 1 and 2.

Claims (4)

Sulfur content is 10 mass ppm or less, styrene compound content of 10 or less carbon atoms is 0.15 mass% or less in total, and diene compound content of 15 or more carbon atoms is 0.73 mass% or more and 2.00 in total. A gas oil composition having a mass index of IO or less and an oxidation index IO of 0.5 or less.
IO = (C10LST) + 3 × (C17HDI) − (R2A) −5 × (R3A)
(C10LST: C10 or less styrene compound content, mass%, C17HDI: Diene compound content of 17 or more carbon atoms, mass%, R2A: Bicyclic compound contained in condensed polycyclic aromatic hydrocarbons Amount, mass%, R3A: tricyclic compound content in condensed polycyclic aromatic hydrocarbon, mass%)   The light oil composition according to claim 1, wherein the total content of styrene compounds having 10 or less carbon atoms is 0.10 mass% or less.   The gas oil composition according to claim 1 or 2, wherein the total content of the bicyclic and tricyclic condensed polycyclic aromatic hydrocarbons is 0.10% by mass or more.   The light oil composition according to any one of claims 1 to 3, wherein the total content of diene compounds having 17 or more carbon atoms is 1.00% by mass or less.