JP5352057B2 - Method for producing fuel oil base material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a production method of a fuel oil base material of extremely low sulfur content but nevertheless having excellent oxidation stability by controlling the content of the materials effecting to oxidation stability of fuel oil. <P>SOLUTION: The production method of fuel oil base materials, obtaining a fuel oil base material having &le;3 mass ppm sulfur, 5-20 vol.% aromatics, &ge;0.05 vol.% content of condensed polycyclic aromatic hydrocarbon having &ge;2 rings but no saturated ring and of the aromatics, and &le;2.00 vol.% total of styrenes and dienes, by contacting in the coexistence of hydrogen, a stock oil having 5-10 mass ppm sulfur and 10-21 vol.% aromatics, with a porous desulfurizing agent having sulfur absorbing function, is provided. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a method for producing a fuel oil base, and more particularly to a method for producing a light oil base having excellent oxidation stability while having a very low sulfur content.

  Light oil used for diesel engine fuel, etc. is discolored during storage, formation of precipitated polymer (sludge), increased viscosity, etc. Peroxide produced by oxidation is It is known to deteriorate fuel system 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, due to stricter exhaust gas regulations for diesel engines, the pressure increase of fuel injection by the common rail system has further increased, increasing the thermal load on light oil and increasing the oxidation stability of light oil more than before. .

  Further, so-called sulfur-free fuel oil having almost no sulfur content has been put on the market since January 2005 to prevent poisoning of the exhaust gas purification catalyst. Further, against the background of fuel consumption regulations, carbon dioxide emission reduction, and toxic substance reduction in exhaust gas, the sulfur content of light oil is required to be lower than 10 ppm by mass. In order to remove the sulfur content, a hydrodesulfurization method is generally performed in which hydrogen is blown into light oil under high temperature and high pressure to be brought into contact with a solid catalyst to remove the sulfur content as hydrogen sulfide. However, when subjected to a heat load at a high temperature in the process of highly removing sulfur, unstable substances are often generated in light oil, and oxidation stability is often impaired. Therefore, in the hydrodesulfurization reaction that removes the sulfur content of light oil, it is conceivable to reduce the temperature to suppress the production of a substance having a hydrocarbon structure unstable to oxygen.

In addition, when the catalytic activity of hydrodesulfurization decreases, it becomes difficult to remove the sulfur content, and nitrogen compounds such as indoles, which are generally contained in catalytic cracking gas oil and pyrolysis gas oil, which are generally used in feedstock oil, are hydrogenated. It tends to remain in the product even after hydrodesulfurization, which also 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. As an example of adding an antioxidant to light oil whose sulfur content is reduced to 10 mass ppm or less, N, N′-diisopropyl-p-phenylenediamine or the like is used as an amine-based antioxidant, and 2,6 as a phenol-based antioxidant. It has been proposed to use -di-tert-butyl-4-methylphenol or the like (Patent Document 1).

  However, in the method of adding an antioxidant additive, the additive effect of the additive is not stable because the composition of the light oil changes depending on the temperature history during production. In addition, the added additive is consumed to prevent oxidation during storage. Therefore, after the additive amount is small and the antioxidant effect of the additive is exhausted, the oxidation stability of the light oil is remarkably deteriorated, resulting in adverse effects such as engine cleanliness and corrosion of the metal material. In addition, due to an increase in thermal load on light oil accompanying the high pressure injection of diesel engines, the level of required oxidative stability for light oil increases, and this requires an increase in the amount of additive. However, when a large amount of additive is added, the additive is likely to precipitate when the temperature of the light oil is lowered, and the pipes and the like are clogged.

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. However, according to the study by the present inventors, even when the content of fluorenes, naphthenebenzenes and naphthalenes is in a specific range as described in Patent Document 2, there are cases where sufficient oxidation stability is not exhibited. It was found that there were components other than the above components that significantly affected the oxidation stability.
The present applicant has already proposed a method for reducing the sulfur content without significantly reducing the aromatic content (Patent Document 3), but did not consider the deterioration of oxidation stability due to the reduction of the sulfur content. .
JP 2004-225000 A JP 2006-137922 A International Publication No. 2006/070660

  The present invention provides a method for producing a fuel oil base material having excellent oxidation stability while controlling the content of a substance that significantly affects the oxidation stability of the fuel oil to a specific range while having a very low sulfur content. The issue is to provide.

  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 diene residues, or the production of trace amounts of styrenes and dienes that occur in the gas oil refining process, the reduction of trace amounts of naphthalenes, and the formation of naphthenebenzenes by hydrogenation of polycyclic aromatics with 3 or more rings It was found to be due to. Further, styrenes having 10 or less carbon atoms and dienes having 17 or more carbon atoms have a significant adverse effect on oxidation stability, and among condensed polycyclic aromatic hydrocarbons, bicyclic and tricyclic condensed polycyclic aromatics. It has been found that hydrocarbons have the effect of stabilizing the active species generated during the oxidation process of light oil. By restricting these amounts to a specific range, it was found that deterioration of oxidation stability can be suppressed, and in the production method, it was found useful to contact with a specific porous desulfurizing agent. I came up with it.

That is, this invention is a manufacturing method of the fuel oil base material as follows.
(1) By bringing a raw material oil having a sulfur content of 5 to 10 ppm by mass and an aromatic content of 10 to 21% by volume into contact with a porous desulfurization agent having a sulfur sorption function in the presence of hydrogen, sulfur The content is 3 ppm by mass or less, the aromatic content is 5 to 20% by volume, and the content of condensed polycyclic aromatic hydrocarbons of 2 or more rings having no saturated ring in the aromatic content is 0.05% by volume or more. A method for producing a fuel oil base material, comprising obtaining a fuel oil base material.
(2) The reduction rate of the condensed polycyclic aromatic hydrocarbon content of two or more rings having no saturated ring before and after contact with the porous desulfurization agent is 20% or less, and the total content of styrenes and dienes The method for producing a fuel oil base material according to (1), wherein the increase rate is 20% or less.
(3) The method for producing a fuel oil base material according to (1) or (2), wherein the porous desulfurization agent having a sulfur sorption function is a porous desulfurization agent containing nickel and zinc.
(4) The condensed polycyclic aromatic hydrocarbon content of 3 or more rings having a saturated ring in the aromatic content of the fuel oil base material is 0.10% by volume or less in any one of (1) to (3) The manufacturing method of the fuel oil base material of description.
(5) The manufacturing method of the fuel oil base material in any one of (1)-(4) whose true calorific value of a fuel oil base material is 42,500 kJ / kg.

  In the present invention, a specific feedstock is brought into contact with a porous desulfurization agent having a sulfur sorption function in the presence of hydrogen, and in particular, a condensed polycyclic aromatic hydrocarbon having two or more rings having no saturated ring. The reduction rate is limited to a specific amount or less and the content is 0.05% by volume or more, and the increase rate of styrenes and dienes is limited to a specific amount or less and the content is 2.00% by volume or less. Since it is a manufacturing method of a certain fuel oil base material, the obtained fuel oil base material has excellent oxidation stability even though the sulfur content is as extremely low as 3 ppm by mass or less. When this fuel oil base material is used, for example, as a fuel oil for a diesel engine, the bad odor and environmental load caused by sulfurous acid gas generated by combustion is reduced, and an oxidation polymer produced by auto-oxidation during storage or a diesel engine. It has the effect of reducing the amount of oxidized polymer that is generated by the thermal load received during high-pressure injection, and as a result, the amount of additives such as antioxidants can be reduced or no additives are required. There is an extraordinary effect of cost reduction.

  The present inventor has found that unsaturated compounds greatly affect the oxidative stability of a light oil composition, and the deterioration of oxidative stability is caused by residual styrenes and dienes contained in a trace amount in a raw material oil (or base material), or light oil. It has been found that this is caused by the generation of trace amounts of styrenes and dienes that occur during the process of reducing the sulfur content in the process, and by the reduction of trace amounts of condensed polycyclic aromatic hydrocarbons.

Most or all of the styrenes contained in the light oil composition have 10 or less carbon atoms, and the oxidative stability of the light oil composition can be improved by controlling styrenes having 10 or less carbon atoms. Even styrenes having 11 or more carbon atoms may have an adverse effect on oxidation stability, but are usually not detected in light oil compositions, and even if detected, they are negligible amounts.
Specific examples of styrenes having 10 or less carbon atoms found in these light oil compositions include styrene, methylstyrene, dimethylstyrene, and the like, and styrene mainly contained in light oil is dimethylstyrene.

  Further, most of the dienes contained in light oil are those having 15 or more carbon atoms, and dienes having 17 or more carbon atoms are rich in oxidation reactivity due to changes in content before and after oxidation treatment of light oil. In particular, those having 17 or more carbon atoms are considered to have a great adverse effect 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.

  It is mainly octadecadiene (for example, bicyclo [10.6.0] octadeca-1 (12), 15-diene (C18H30) that is found in the gas oil composition as a specific compound of dienes having 17 or more carbon atoms. ) And tetramethylphenylbicycloheptadiene (for example, 1,5,6,7-tetramethyl-3-phenylbicyclo [3.2.0] hepta-2,6-diene (C17H20)), and the like. Often, dienes having a structure of 17 or more carbon atoms, typically 17 to 20 carbon atoms, more typically 17 and 18 carbon atoms are found.

  The condensed polycyclic aromatic hydrocarbon has the effect of stabilizing the active species generated in the oxidation process of the light oil, so that the adverse effect of dienes and styrenes on the oxidation stability can be mitigated. In particular, since the effect of two- and three-ring condensed polycyclic aromatic hydrocarbons is great, the fuel composition containing a large amount of two- and three-ring condensed polycyclic aromatic hydrocarbons with respect to the condensed polycyclic aromatic hydrocarbons Or by reducing the hydrogen partial pressure of the desulfurization operating conditions and increasing the reaction temperature to increase the oxidation stability of the light oil composition. In the present invention, a condensed polycyclic aromatic hydrocarbon having two or more rings refers to a hydrocarbon having any one of a naphthalene ring, an anthracene ring, a phenanthrene ring, and a phenalene ring in the molecule. However, a compound having a condensed or non-condensed saturated ring (eg, tetralin ring, cycloalkane ring) in the molecule (eg, 9,10-dihydroanthracene) does not contribute to improvement in oxidation stability, Even if it has an anthracene ring or a phenanthrene ring, it is excluded from two or more condensed polycyclic aromatic hydrocarbons.

  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.

  Based on the above knowledge, the present inventors have found that a condensed polycyclic aromatic hydrocarbon having an aromatic content of 5 to 20% by volume and having no saturated ring, even if the sulfur content is 3 mass ppm or less. It has been found that a desulfurized oil (fuel oil base material) having a content of 0.05% by volume or more and a total content of styrenes and dienes of 2.00% by volume or less has excellent oxidation stability. . Thus, as a result of various studies on methods for obtaining such desulfurized oil, it has been found that a hydrocarbon oil having specific properties can be obtained by contacting with a porous desulfurizing agent. The method is described below.

(Raw oil)
The raw material oil used in the present invention has a sulfur content of 5 to 10 mass ppm and an aromatic content of 10 to 21% by volume. If the sulfur content of the feedstock is too high, the desulfurization temperature and pressure will increase, and the content of styrenes and dienes after desulfurization will increase. If the sulfur content of the feedstock is too low, the sulfur content already passed will be removed. In this hydrorefining step, it is generally predicted that the process was performed under considerably severe conditions, so that the feedstock oil is expected to contain a large amount of styrenes and dienes. For this reason, the sulfur content of the raw material oil is preferably 5.2 to 9.6 mass ppm, more preferably 5.4 to 9.2 mass ppm, and particularly preferably 5.6 to 8.8 mass ppm.

In addition, if the aromatic content of the raw material oil is small, the aromatic content after desulfurization decreases and the effect of improving oxidation stability decreases, but conversely, if it is too large, the oxidation stability is generally improved by performing desulfurization treatment. Among the aromatic components to be deteriorated, the number of condensed polycyclic aromatic hydrocarbons having no saturated ring, for example, 9,10-dihydroanthracene increases. For this reason, the aromatic content of the feed oil is preferably 11 to 20% by volume, more preferably 12 to 19% by volume, and particularly 13 to 18% by volume.
Moreover, the condensed polycyclic aromatic hydrocarbon content of two or more rings having no saturated ring in the aromatic component is preferably 0.05 to 1.00% by volume.

  The total content of styrenes and dienes in the feedstock oil is preferably 0.10 to 2.00% by volume. In order to suppress the content of styrenes and dienes after desulfurization and obtain an effect of improving oxidation stability, the total content of these is preferably 0.11 to 1.90% by volume, more preferably 0.12 to 1.70% by volume, in particular 0.13-1.60% by volume. If the total content of styrenes and dienes in the feedstock is less than 0.10% by volume, it is presumed that the desulfurization treatment for removing the sulfur content of the feedstock was performed under mild conditions. Therefore, it is difficult to produce a fuel oil base material having a sulfur content of 3 ppm by mass or less.

  Examples of the hydrocarbon oil that can be used as the raw material oil include a light oil fraction obtained from an atmospheric distillation device, a catalytic cracking device, a thermal cracking device, or the like, that is, a fraction distilled at a boiling point of 140 to 400 ° C. However, in order to reduce the content of styrenes and dienes that adversely affect oxidation stability, the raw materials that contain a large amount of these compounds, such as oils that are pyrolyzed asphalt, are reduced. It is preferable to adjust the oil to the above conditions.

(Porous desulfurization agent)
The feedstock is a bicyclic ring that does not have a saturated ring when it comes into contact with a porous desulfurization agent having a sulfur sorption function in the presence of hydrogen, with a sulfur content of 3 mass ppm or less, an aromatic content of 5 to 20% by volume. The above-mentioned condensed polycyclic aromatic hydrocarbon content is converted into a fuel oil base material having a content of 0.05% by volume or more and a total content of styrenes and dienes of 2.00% by volume or less. That is, in the present invention, the sorption / removal sulfur is performed by a method in which a porous desulfurization agent having a sulfur sorption function is brought into contact with a raw material oil in the presence of hydrogen.
The porous desulfurization agent having a sulfur sorption function used in the present invention is a desulfurization agent that adsorbs an organic sulfur compound and cleaves a carbon-sulfur bond in the organic sulfur compound to remove a sulfur atom in the organic sulfur compound. The hydrocarbon residue other than the sulfur atom in the organic sulfur compound is a porous desulfurizing agent having a function of desorbing from the desulfurizing agent by cleavage. When this hydrocarbon residue is eliminated, hydrogen present in the system is added to carbon whose bond with sulfur has been cleaved. Therefore, a hydrocarbon compound obtained by removing sulfur atoms from the organic sulfur compound is obtained as a product. However, the hydrocarbon compound from which the sulfur atom is removed may give a product that has undergone a reaction such as hydrogenation, isomerization, or decomposition. On the other hand, since sulfur is fixed to a desulfurizing agent, it can be desulfurized without generating a sulfur compound such as hydrogen sulfide as a product, unlike hydrorefining.

This porous desulfurization agent is not particularly limited as long as it has a sorption function for organic sulfur compounds, but only hydrogen sulfide can be removed if the metal contained in the porous desulfurization agent is only zinc, copper, Even with other metals such as nickel, organic sulfur compounds cannot be sufficiently desulfurized with only one kind. In order to increase the capacity of sulfur incorporation into the desulfurizing agent, it is preferable to use a metal selected from zinc as the first metal and copper, nickel, cobalt and iron as the second metal. Particularly preferably, the first metal is zinc and the second metal is a combination of nickel.
The method for producing the porous desulfurization agent of the present invention is not particularly limited and can be obtained by a coprecipitation method or an impregnation method. However, the coprecipitation method is used to precipitate metal components such as zinc and nickel, and to perform filtration and washing. It is particularly preferable to obtain a porous desulfurization agent through steps such as molding and firing.

  The porous desulfurizing agent preferably contains 50 to 85% by mass, particularly 60 to 80% by mass of the total amount of metal components such as nickel and zinc. These metal components are usually contained in the desulfurizing agent in the form of oxides or sulfides. Although it does not specifically limit as another component, For example, the element of the 2nd, 4th, 13th, and 14th group of a periodic table can be used. Among these, silicon, aluminum, zirconium, calcium and the like are preferable, and these can be used alone or in combination of two or more. The method for adding these other components is not particularly limited, but when the first metal and the second metal are precipitated by the coprecipitation method, they may be added in the presence of oxides and salts of other components. Particularly preferred. Alternatively, after the first metal and the second metal are precipitated by a coprecipitation method, the oxides and oxide precursors of other components are mixed into the composite oxide obtained by drying and firing by a kneading method. The addition is also a preferred method. In order to improve the desulfurization performance or to use it industrially, it may be preferable to mold by adding other components. In order to improve the desulfurization performance or to use it industrially, it can be molded by further adding other components. The porous desulfurizing agent thus obtained is preferably used after reduction treatment in a hydrogen atmosphere. The specific surface area of the desulfurizing agent is preferably 30 to 200 m <2> / g, particularly 50 to 150 m <2> / g, more preferably 50 to 100 m <2> / g.

(Desulfurization treatment conditions)
The sorption / removal sulfur treatment using the porous desulfurizing agent described above is not particularly hindered whether it is performed in a batch mode or a flow mode, but is a porous material having a sulfur sorption function packed in a fixed bed flow mode reactor. A mode in which hydrogen and raw material oil are continuously supplied to and contacted with the desulfurizing agent is preferable. The temperature for the desulfurization treatment can be selected from the range of 0 to 500 ° C, preferably 100 to 380 ° C, more preferably 200 to 350 ° C. When the reaction temperature is less than 100 ° C., desulfurization hardly proceeds. On the other hand, when the reaction temperature exceeds 500 ° C., the metal component in the porous desulfurization agent may be sintered and the desulfurization activity may be greatly reduced.

  The hydrogen pressure for the desulfurization treatment is preferably 0.5 to 4 MPa, and more preferably 1 to 3 MPa. When the pressure is less than 0.5 MPa, polycyclic aromatics may increase due to the dehydrogenation reaction, and desulfurization may not proceed easily. On the other hand, when the hydrogen pressure exceeds 4 MPa, a large amount of polycyclic aromatics may be hydrogenated to lower the oxidation stability. Furthermore, a considerable amount of monocyclic aromatics are hydrogenated, resulting in a very large hydrogen consumption.

  When the desulfurization treatment is performed by contacting the porous desulfurization agent and the gas oil fraction in a fixed bed flow type, LHSV is preferably in the range of 1 to 100 h-1, more preferably 2 to 30 h-1, particularly 3 to 10 h-1. Choose from. If LHSV is less than 1 h-1, the reactor for collecting and removing sulfur becomes too large. If the LHSV exceeds 50 h-1, sufficient time cannot be obtained for collecting and removing. The hydrogen / oil supply ratio is preferably selected in the range of 10 to 1,000 NL / L, more preferably in the range of 10 to 500 NL / L, and particularly in the range of 100 to 500 NL / L. When the hydrogen / oil supply ratio is less than 10 NL / L, polycyclic aromatics are hardly reduced, and desulfurization is difficult to proceed. When the hydrogen / oil supply ratio exceeds 1,000 NL / L, the capacity of the compressor that supplies hydrogen becomes too large.

(Desulfurized oil)
In the present invention, the raw material oil is collected and removed, and a desulfurized oil (fuel oil base material) having a sulfur content of 3 mass ppm or less is obtained. The sulfur content of the fuel oil base material, taking into account the adverse effects on exhaust gas purification catalyst activity decline, which is a concern when preparing fuel oil for diesel engines, and material corrosion due to sulfurous acid gas during exhaust gas circulation, 2.0 mass ppm or less is preferable, more preferably 1.0 mass ppm or less, and particularly preferably 0.7 mass ppm or less.

  In the present invention, a desulfurized oil (fuel oil base material) having an aromatic content of 5 to 20% by volume is obtained. The aromatic content is preferably 5.2% by volume or more, more preferably 5.4% by volume or more, and particularly 5.6% by volume or more from the viewpoint of improving the oxidation stability. When the aromatic content is large, deterioration in exhaust gas properties is likely to occur when used in fuel oil for diesel engines. Therefore, it is preferably 19.6% by volume or less, more preferably 19.0% by volume or less, especially 18.0% by volume or less.

  Further, in the present invention, the content of the condensed polycyclic aromatic hydrocarbon of 2 or more rings having no saturated ring in the aromatic component contained in the fuel oil base material is 0.05% by volume or more, and good oxidation Ensure stability. The amount is preferably 0.08% by volume or more, more preferably 0.11% by volume or more, and particularly preferably 0.30% by volume or more.

  Further, in the present invention, the increase in the content of styrenes and dienes is suppressed, and the oxidation by the decrease in the content of condensed polycyclic aromatic hydrocarbons having two or more rings that do not have a saturated ring, which has an effect of improving oxidation stability. In order to suppress the deterioration of stability, the rate of decrease in the content of condensed polycyclic aromatic hydrocarbons having two or more rings without saturated rings before and after detachable sulfur is 20% or less, preferably 15% or less, particularly preferably Is 10% or less. However, if the content of the polycyclic aromatic hydrocarbon compound is too large, the combustibility deteriorates and the amount of nitrogen oxides and particulate matter in the exhaust gas of the diesel vehicle increases. Or less, more preferably 0.98% by volume or less, and particularly preferably 0.96% by volume or less. In particular, a compound in which one ring is hydrogenated among three or more polycyclic aromatics such as 9,10-dihydroanthracene deteriorates oxidation stability because it is rich in oxidation reactivity. Preferably it is 0.10 volume% or less, More preferably, it is 0.08 volume% or less, Especially 0.05 volume% or less.

  In the present invention, the total content of styrenes and diene compounds in the desulfurized oil (fuel oil base material) is 2.00% by volume or less, 1.90% by volume or less, more preferably 1.80% by volume or less. . In particular, the content of styrenes and diene compounds is preferably 1.60% by volume or less so as not to adversely affect oxidation stability.

Also, since styrenes and dienes deteriorate the oxidation stability, the increase rate of the total content before and after the desulfurization treatment is set to 20% or less, preferably 15% or less, more preferably 12% or less, particularly 10%. % Or less is preferable.
About each component of the said styrenes, dienes, and various condensed polycyclic aromatic hydrocarbons, the content can be measured by the gas chromatography mentioned later.

  The desulfurized oil (fuel oil base material) preferably has a true calorific value of 42,500 kJ / kg or more, more preferably, in order to obtain good fuel efficiency when used in a diesel engine fuel oil. It is 42,800 kJ / kg or more, more preferably 43,000 kJ / kg or more, particularly 43,100 kJ / kg or more.

(Method for producing light oil composition)
A light oil composition (diesel engine fuel oil) can be produced using the desulfurized oil (fuel oil base material) obtained by the above-described method. If the quality is satisfactory, it may be a light oil composition only with desulfurized oil (fuel oil base material), and other base materials such as kerosene fraction with good oxidation stability and low-temperature fluidity are improved. Alternatively, it may be produced by mixing at an appropriate ratio with a distillate having 11 or more carbon atoms obtained from a catalytic reformer containing a large amount of 2- and 3-ring condensed polycyclic aromatic hydrocarbons. It is preferable to contain at least 50% by volume of the desulfurized oil, and more desirably 80% by volume or more.

  By this method, fuel consumption regulations and carbon dioxide emissions have properties such that sulfur content is 3 mass ppm or less, aromatic content is 5 to 20% by volume, and total content of styrenes and dienes is 2.00% by volume or less. It is possible to obtain a light oil composition effective for reduction and reduction of toxic substances in exhaust gas, particularly a light oil composition having excellent oxidation stability while having a very low sulfur content.

  The light oil composition comprising the fuel oil base material obtained in the present invention is excellent in oxidation stability without the addition of an antioxidant, but in order to further improve the performance, the oxidation usually used in fuel oils An inhibitor may be added. Antioxidants can be used without any particular limitation. For example, 2,6-ditertiary butylphenol, 2,6-ditertiarybutyl-4-methylphenol, 2,4-dimethyl-6-tertiarybutylphenol and mixtures thereof Is mentioned.

  In addition, other known fuel additives such as a low-temperature fluidity improver, an abrasion resistance improver, and a cetane number improver can be added. As the low-temperature fluidity improver, an ethylene copolymer or the like can be used. In particular, vinyl esters of saturated fatty acids such as vinyl acetate, vinyl propionate and vinyl butyrate are 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 present invention will be described in more detail based on examples and comparative examples. The present invention is not limited to the following examples.

(Preparation of raw oil)
CoMo / alumina (cobalt content 3% by weight, molybdenum content 13% by weight) and NiMo / alumina (nickel content 3% by weight, molybdenum content 12% by weight) prepared by the loading method in a volume ratio of 1: After passing through a reaction tube filled to 2 with 1% by weight of light oil containing dimethyl disulfide as a pretreatment in the presence of hydrogen at 300 ° C in the presence of 5 MPa, sulfidation was performed and then distilled from the atmospheric distillation unit. The raw gas oil was obtained by hydrorefining a straight-run gas oil fraction having a boiling range of 140 to 370 ° C. under conditions of a reaction temperature of 340 ° C., a reaction pressure of 6 MPa, a hydrogen / oil ratio of 200 Nm 3 / kL, and an LHSV of 0.7 h−1. As a hydrodesulfurized gas oil was prepared.

  As a porous desulfurization agent having a sulfur sorption function, a nickel zinc composite oxide (nickel content: 7 mass%, zinc content: 68 mass%) was prepared by a coprecipitation method. The hydrodesulfurized gas oil (raw oil) obtained as described above is brought into contact with a nickel-zinc composite oxide subjected to reduction treatment as a porous desulfurizing agent under the following conditions to form a fuel oil base material 1 (Example 1). The fuel oil base material 2 (Example 2) and the fuel oil base material 3 (Comparative Example 1) were obtained.

Example 1 (Manufacture of fuel oil base material 1)
A nickel-zinc composite oxide as a porous desulfurizing agent was filled in a reaction tube, and hydrogen gas was passed through the reaction tube at a temperature of 300 ° C. for 6 hours for reduction treatment. Thereafter, the raw material oil (hydrodesulfurized gas oil) and hydrogen prepared as described above were added to the reaction tube at a reaction temperature of 300 ° C., a reaction pressure of 1.0 MPa, LHSV 5.0 h-1, and a hydrogen / oil supply ratio of 200 Nm 3 / L. The fuel oil base material 1 was obtained by passing through the oil for 20 hours under the conditions of

Example 2 (Production of fuel oil base material 2)
Exactly the same as Example 1 except that the feedstock oil was passed through the reaction tube for 20 hours under the conditions of a reaction temperature of 300 ° C., a reaction pressure of 2.0 MPa, LHSV 5.0 h-1, and a hydrogen / oil supply ratio of 200 Nm 3 / L. The fuel oil base material 2 was obtained by collecting and detaching sulfur by the method.

Comparative Example 1 (Manufacture of fuel oil base material 3)
Exactly the same as Example 1, except that the feedstock oil was passed through the reaction tube at a reaction temperature of 300 ° C., a reaction pressure of 5.0 MPa, LHSV 5.0 h-1, and a hydrogen / oil supply ratio of 200 Nm 3 / L for 20 hours. The fuel oil base material 3 was obtained by collecting and removing sulfur by the method.

  Table 1 shows the evaluation results of the properties and oxidation stability of the raw material oil and the fuel oil base materials 1 to 3.

The physical property measurement method and the oxidation stability evaluation method are as follows.
1) Density: The method specified in JIS K2249 “Crude oil and petroleum product density test method”.
2) Kinematic viscosity (30 ° C.): A method defined in JIS K2283 “Crude oil and petroleum product kinematic viscosity test method”.
3) Color (Saebold): A method defined in JIS K2580 “Crude oil and petroleum product color test method”.
4) Sulfur content: A method defined in JIS K2541-6 “Sulfur content test method (ultraviolet fluorescence method)”.
5) Cetane index: The method specified in JIS K2280 “Testing method for octane number and cetane number and cetane index calculation method”.
6) True calorific value: A method defined in JIS K2279 “A calorific value test method and calculation estimation method”.
7) Distillation property: A method defined in JIS K2254 “Distillation Test Method”.

8) Aromatic content: The method specified in JPI-5S-49-97 "Petroleum products-Hydrocarbon type test method-High performance liquid chromatograph method".
9) Component (dienes, condensed polycyclic aromatics with or without hydrogenated rings): Measured using gas chromatography in which two gas chromatography columns with different polarities are connected in series via a modulator . Detailed conditions are as follows.
GC system: After passing through the primary column, the mass transfer is controlled by the modulator, and then the oil is passed through the secondary column and separated by the difference in polarity. The analyzer system configuration is composed of GC with HP-6890N FID detector manufactured by Agilent Technologies, and 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 rise conditions: 50 ° C. (5 minutes hold) → 280 ° C. (27 minutes hold) Temperature rise rate 10 ° C./min 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) → 320 ° C. (33 min hold) Temperature rising rate 10 ° C./min Cold jet gas temperature: about −140 ° C.
Modulator frequency: 0.3 seconds hot temperature for 6 seconds, then 5.7 seconds cold temperature Interface hollow column: 0.5m length, 0.25mm ID
FID gas conditions: hydrogen (45 mL / min), air (450 mL / min), make-up helium (25 mL / min, constant)

10) Oxidation stability evaluation test:
In accordance with the oxidative stability test method of the quality assurance method applied to BDF blended light oil (biodiesel fuel blended light oil), each fuel oil base material 300mL was put in a pressure vessel, and oxygen was blown at 3 L / h, while 115 ° C After accelerating the oxidation test to forcibly degrade the diesel oil by holding it for 16 hours in a constant temperature bath, after taking out each pressure vessel containing the degraded fuel oil base material from the constant temperature bath and lowering the temperature to room temperature The total acid value was measured by the following method. Table 1 shows the total acid value of each deteriorated fuel oil base material as an increase rate of the total acid value after the oxidation treatment based on the total acid value of the oxidized and deteriorated product of the raw material oil.
11) 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 “Testing method for aviation fuel oil”.

From Table 1, although Example 1 produces a small amount of styrenes, the number of condensed polycyclic aromatics having 2 or more rings not having a saturated ring is increased, and condensed polycyclic aromatics having 3 or more rings having a saturated ring. Since the remaining or generation of the group is suppressed, it can be seen that the increase rate of the total acid value after the oxidation treatment is very small at −33% based on the raw material oil, and the oxidation stability is good. Further, in Example 2, the condensed polycyclic aromatic having 2 or more rings having no saturated ring is the same amount as the raw material oil, and the remaining or generation of the condensed polycyclic aromatic having 3 or more rings having a saturated ring is suppressed. I understand that. Comparative Example 1 reduces the number of dienes and suppresses the formation of styrenes, but the number of condensed polycyclic aromatics having two or more rings that do not have a saturated ring decreases, and three or more condensed polycyclics having a saturated ring. Aromatics remain or are produced, the rate of increase in the total acid value after the oxidation treatment is as large as 190%, and the oxidation stability is remarkably deteriorated.

Claims (4)

A feedstock having a sulfur content of 5 to 10 mass ppm, an aromatic content of 10 to 20 % by volume , and a total content of styrenes and dienes of 0.10 to 2.00% by volume in the presence of hydrogen , By contacting with a porous desulfurization agent having a sulfur sorption function containing nickel and zinc under conditions of a temperature of 0 to 500 ° C. and a hydrogen pressure of 0.5 to 4 MPa , the sulfur content is 3 mass ppm or less, aromatic 5-20% by volume, a condensed polycyclic aromatic hydrocarbon content of 2 or more rings not having a saturated ring is 0.05% by volume or more, and the total content of styrenes and dienes is 2.00 volumes A method for producing a fuel oil base material, wherein the fuel oil base material is at most%.   Decrease rate of condensed polycyclic aromatic hydrocarbon content of 2 or more rings having no saturated ring before and after contact with porous desulfurization agent is 20% or less, and increase in total content of styrenes and dienes The method for producing a fuel oil base material according to claim 1, wherein the rate is 20% or less. The production of a fuel oil base material according to claim 1 or 2, wherein the content of the condensed polycyclic aromatic hydrocarbon having 3 or more rings having a saturated ring in the aromatic content of the fuel oil base material is 0.10% by volume or less. Method. The method for producing a fuel oil base material according to any one of claims 1 to 3 , wherein the true heat generation amount of the fuel oil base material is 42,500 kJ / kg or more.