JP4881662B2 - LIGHT OIL COMPOSITION AND METHOD FOR PRODUCING LIGHT OIL COMPOSITION - Google Patents

Description

  The present invention relates to a light oil composition. In detail, it is related with the light oil composition mainly used for the fuel of a diesel engine. More specifically, the present invention relates to a light oil composition that enables precise operation control for suppressing corrosion of a fuel injection system and reducing environmental impact to be maintained for a longer period of time.

Emission regulations for diesel vehicles are becoming stricter year by year, and automakers are trying to clear the regulations with various technologies. Among these techniques, the most frequently employed is high-pressure fuel injection equipped with a pressure accumulator called a common rail fuel injection device. This device not only reduces particulate matter by atomizing light oil droplets in high-pressure injection, but also enables multiple fuel injections during one cycle, so that the optimal injection timing and number of injections are precise. Is electronically controlled.
However, in the common rail fuel injection device, the fuel temperature rises considerably because the pressure is increased by the pressure accumulator and the accumulator itself is directly connected to the engine. Furthermore, since the amount of fuel returned to the fuel tank without being injected is considerably larger than that of the conventional mechanical injection device, the fuel temperature in the fuel tank also rises (Non-Patent Document 1).
When the fuel temperature rises, the thermal stability of light oil may become a problem, and the fuel injection valve, fuel pump, etc. will deteriorate during long-term use, making precise fuel injection by electronic control impossible There is a fear.
Kazuyoshi Ishizaka, “Common Rail Diesel Fuel Injection System”, Toyota Technical Disclosure Collection, 16303, 2004

  Although there is no JIS standard that regulates the stability and corrosivity of light oil compositions, in general, the stability is controlled by hue, and it is considered that the acid value and the like can also be diverted. Further, as a method for evaluating the corrosiveness of the light oil composition to the engine material, it is considered that the copper plate corrosion for 3 hours at 50 ° C. used for gasoline and kerosene can be diverted. However, these evaluation methods were developed in the era of conventional mechanical fuel injection devices, and are not necessarily sufficient in terms of accuracy for cases where the fuel temperature rises as in common rail fuel injection devices. I can't say that. Moreover, even if it is a light oil composition evaluated as having favorable stability based on the said parameter | index, operation | movement of a fuel-injection apparatus may become unstable with a long-term use of a diesel engine. This is because the above index evaluates the properties of the light oil composition and does not identify direct factors involved in the stability and corrosivity of the light oil composition.

  The present invention is a light oil composition for stably operating a diesel engine for a longer period of time, and can suppress corrosion as much as possible even when the fuel temperature rises by a fuel injection device, and more precise combustion control can be achieved. It aims at providing the light oil composition which makes possible for a long term.

  As a result of diligent research to solve the above-mentioned problems of the prior art and to achieve the above-mentioned object, the present inventors have found that, among the sulfur content in light oil, the sulfur content of mercaptans and n-decyl mercaptan (1-decane). The sulfur content of sulfur compounds heavier than dithiothiophene and lighter than dibenzothiophene can affect the corrosive action in diesel engine fuel injection systems, and by selectively reducing these sulfur contents The inventors have found that even if the temperature of the fuel oil rises, the corrosivity can be reduced and the above object can be achieved, and the present invention has been completed.

That is, the present invention is characterized by the following (1) to (5).
(1) A desulfurized gas oil composition obtained by subjecting a base material containing straight run gas oil obtained from crude oil by atmospheric distillation to a hydrogenation treatment, and having the following properties (a) to (c): A gas oil composition characterized by satisfying.
(A) 3-10 mass ppm of total sulfur content
(B) Among the total sulfur content, the sulfur content of mercaptans is 0.4-2 mass ppm.
(C) Among the total sulfur content, the sulfur content of the sulfur compound heavier than n-decyl mercaptan (1-decanethiol) and lighter than dibenzothiophene is 0.4 mass ppm or less.
(2) The gas oil composition as described in (1) above, wherein the base material further contains at least one selected from desulfurized kerosene, light vacuum gas oil, and catalytic cracked gas oil.
(3) The light oil composition as described in (1) above, wherein the base material further contains desulfurized kerosene.
(4) The base material is subjected to a hydrogenation treatment at a temperature of 330 to 400 ° C. with a Co—Mo, Ni—Mo, or Ni—Co—Mo catalyst. The gas oil composition according to any one of the above.
(5) A base material containing straight run gas oil obtained from crude oil by atmospheric distillation is hydrotreated with a Co—Mo, Ni—Mo, Ni—Co—Mo catalyst at a temperature of 330 to 400 ° C.,
(A) 3-10 mass ppm of total sulfur content
(B) Among the total sulfur content, the sulfur content of mercaptans is 0.4-2 mass ppm.
(C) Among the total sulfur content, the sulfur content of the sulfur compound heavier than n-decyl mercaptan (1-decanethiol) and lighter than dibenzothiophene is 0.4 mass ppm or less.
A process for producing a light oil composition, characterized in that the light oil composition is obtained.

  The total sulfur content, the sulfur content of mercaptans in the total sulfur content of the present invention, and the sulfur content of sulfur compounds heavier than n-decyl mercaptan (1-decanethiol) and lighter than dibenzothiophene are each a constant value. The diesel oil composition managed below can suppress the corrosivity for a longer period in a diesel engine even if the fuel temperature is increased by the fuel injection device. As a result, precise combustion control can be performed for a longer period of time, adverse effects on the combustion state and exhaust gas composition can be reduced as much as possible, and the diesel engine can be stably operated for a longer period of time.

The present invention is described in detail below.
The total sulfur content of the light oil composition of the present invention is 10 mass ppm or less in order to suppress the PM emission amount, and particularly to maintain the effect of reducing the environmental load in an engine equipped with an exhaust gas aftertreatment device for a long period of time. (PM is an abbreviation for Particle Matter, which means particulate matter originating from exhaust gas of diesel engines). In addition, the total sulfur content as used in the field of this invention is the value measured based on JISK2541. The total sulfur content here means all sulfur content contained in light oil compositions such as hydrogen sulfide, mercaptans, alkyl sulfides, cyclic sulfides, and thiophenes.

Moreover, in the light oil composition of this invention, the sulfur content of mercaptans is 2 mass ppm or less, Preferably it is 1 mass ppm or less. The sulfur content of the mercaptans referred to in the present invention is a value measured by the method described in the specification of Japanese Patent Application No. 2005-265598 according to the application of the present applicant. This method is a mercaptan sulfur content test method by potentiometric titration for quantitative analysis of the concentration of mercaptan sulfur in petroleum fuel oil. The concentration of silver nitrate titrant used is 0.0005 to 0.005 mol / L, and This is a method for testing a mercaptan sulfur content of a petroleum-based fuel oil by performing potentiometric titration with a sample weighing of 50 to 500 mL and calculating a mercaptan sulfur content from a titration amount of the silver nitrate titrant measured by the potentiometric titration. .
In the light oil composition of the present invention, the lower the sulfur content of mercaptans, the better. However, if the sulfur content of the mercaptans is 2 ppm by mass or less, the possibility of corrosion occurring in the fuel injection system is reduced. As a result, precise operation control for reducing the environmental impact can be continued for a longer time. The fuel injection system here is a general term for a fuel tank, a fuel filter, a fuel pump, a common rail, a fuel injection valve, and a pipe connecting them.

Furthermore, in the light oil composition of the present invention, the sulfur content of the sulfur compound heavier than n-decyl mercaptan (1-decanethiol) and lighter than dibenzothiophene is 0.4 mass ppm or less, preferably 0.1 mass ppm. It is as follows. Sulfur chemiluminescence detector manufactured by ANTEK, which selectively detects and quantifies sulfur compounds by chemiluminescence, which is heavier than n-decyl mercaptan (1-decanethiol) and lighter than dibenzothiophene in the present invention. Is measured by a gas chromatograph method using a Shimadzu gas chromatograph apparatus. Here, n-decyl mercaptan and dibenzothiophene are used as standard sulfur compounds, and those dissolved in isooctane for HPLC in which no sulfur content is detected are measured in advance to determine the position of the peak. Then, the sample was measured and quantified by the total area of the peaks in the middle of the peak positions of n-decyl mercaptan and dibenzothiophene.
The measurement conditions of the gas chromatograph were maintained at 40 ° C. for 1 minute, then raised to 300 ° C. at 10 ° C./minute, and held at 300 ° C. for 3 minutes. The column used was a capillary type coated with polydimethylsiloxane and had a length of 30 m, an inner diameter of 0.32 mm, and a film thickness of 1.0 μm.
If the sulfur content of the sulfur compound heavier than n-decyl mercaptan (1-decanethiol) and lighter than dibenzothiophene is 0.4 ppm by mass or less, corrosion may occur in the common rail fuel injection system. Therefore, it is possible to maintain precise operation control for a longer period of time to reduce the environmental impact.

  The light oil composition of the present invention can be adapted to the so-called Special No. 1, No. 2, No. 2, No. 3 and Special No. 3 light oils generally referred to in JIS K2204.

  The properties of the light oil composition of the present invention that can be diverted to the evaluation of the stability and corrosivity of the light oil composition, such as the hue, acid value, and copper plate corrosion at 50 ° C. for 3 hours, are the same as the properties of the conventional light oil composition. It doesn't matter if it exists. Each of these properties in the light oil composition of the present invention generally has a hue of -16 or more (Saebold color, JIS K2580) or 1.5 or less (ASTM color, JIS K2580), and an acid value of 0.02 or less (medium It is preferable that the copper plate corrosion at 3 hours at 50 ° C. is less than 2 (copper plate corrosion, JIS K2513). The light oil composition of the present invention preferably further has a judgment value of less than 4 in a copper plate corrosion test at 149 ° C. for 24 hours. This test is a value based on JIS K2513 except that the temperature of the overheating bath is set to 149 ° C. and the time for immersing the sample and the copper plate in the heating bath is 24 hours. Light oil composition in a common rail in an environment where it is installed at the top of the engine and is considered to exceed 100 ° C due to radiant heat by making the conditions more severe than the conventional copper plate corrosion at 50 ° C for 3 hours of JIS K2513 This is an accelerated evaluation of the corrosivity of objects.

The method for producing the light oil composition of the present invention is not particularly limited as long as the above properties are satisfied. For example, the light oil composition of the present invention comprises a straight-run gas oil (LGO) and / or a light vacuum gas oil (LVGO) in the presence of a catalyst such as a Co-Mo, Ni-Mo, or Ni-Co-Mo catalyst. Liquid space velocity (LHSV) 0.1-5 h ⁻¹ , preferably 0.5-1.5 h at a temperature of 300-400 ° C., preferably 330-360 ° C. under a pressure of ˜12 MPa, preferably 7-10 MPa. It is obtained by blending a fluidity improver or the like as necessary after hydrogenation under the condition of ^-1 .
Moreover, it can prepare by arbitrary methods by mix | blending suitably so that the above-mentioned property may be satisfy | filled using another light oil base material. Examples of the light oil base at this time include desulfurized kerosene (UFT-KERO), hydrocracked light oil (HCGO), catalytic cracked light oil (LCO), desulfurized heavy naphtha (DHN), dewaxed desulfurized light oil (DWDLGO), Direct degassing light oil (DSGO), intermediate delighted light oil (VHLGO), kerosene fraction and gas oil fraction produced by Fischer-Tropsch synthesis described in JP-A-6-1558058 . These base materials can be produced by mixing one or more kinds, and one or two or more kinds of these base materials are mixed with straight-run gas oil (LGO) and / or light vacuum gas oil (LVGO). Then, it may be produced by hydrotreating under the above conditions.

  In the light oil composition of the present invention, desulfurized kerosene (UFT-KERO) can be blended in order to improve the cloud point and pour point and to reduce the content of wax contained. Desulfurized kerosene is obtained by hydrodesulfurizing a kerosene fraction obtained from an atmospheric distillation apparatus. The desulfurized kerosene is preferably blended in an amount of 5 to 70% by volume, more preferably 10 to 40% by volume, based on the composition obtained from straight-run gas oil and light vacuum gas oil.

Various additives can be appropriately blended in the light oil composition of the present invention as necessary. Examples of the additive include a fluidity improver, a cetane number improver, a detergent, a rust inhibitor, an antifoaming agent, an antioxidant, a metal deactivator, and a hue stabilizer.
As the fluidity improver, various low temperature fluidity improvers can be used. For example, copolymer polymers such as alkenyl succinic acid amide, ethylene-vinyl acetate copolymer, ethylene-alkyl acrylate copolymer, polyethylene glycol derivative, Examples thereof include polymers such as chlorinated polyethylene and polyalkyl acrylate. Among these, an ethylene-vinyl acetate copolymer is preferable. These fluidity improvers may be used individually by 1 type, and may be used in combination of 2 or more type. The blending amount of the fluidity improver is preferably 100 to 100 in the light oil composition from the viewpoint of appropriately expressing the function of the fluidity improver and avoiding the problem that the fluidity improver itself blocks the automobile filter. The amount contained is 1000 ppm by volume, more preferably 300 to 600 ppm by volume.

  Various cetane number improvers can be used as the cetane number improver, such as 2-chloroethyl nitrate, 2-ethoxyethyl nitrate, isopropyl nitrate, butyl nitrate, first amyl nitrate, and second amylite. Various nights such as rate, isoamyl nitrate, primary hexyl nitrate, secondary hexyl nitrate, n-heptyl nitrate, n-octyl nitrate, 2-ethylhexyl nitrate, cyclohexyl nitrate, ethylene glycol dinitrate Examples include various peroxides such as a rate and di-t-butyl peroxide, and preferably an alkyl nitrate having 6 or 8 carbon atoms. These cetane number improvers may be used individually by 1 type, and may be used in combination of 2 or more type. The blending amount of the cetane number improver may be appropriately selected, but it is preferably blended with 100 to 1000 ppm by volume with respect to the light oil composition.

  Various detergents can be used as the detergent, for example, imide compounds; alkenyl succinimides such as polybutenyl succinimide synthesized from polybutenyl succinic anhydride and ethylene polyamines; pentaerythritol, etc. Succinic acid esters such as polybutenyl succinic acid esters synthesized from polyhydric alcohols of polybutenyl succinic anhydrides; copolymers of dialkylaminoethyl methacrylate, polyethylene glycol methacrylate, vinyl pyrrolidone, etc. and alkyl methacrylate copolymers An ashless detergent such as a polymer is exemplified, and alkenyl succinimide is preferable. These detergents may be used individually by 1 type, and may be used in combination of 2 or more type. The blending amount of the detergent may be appropriately selected, but it is preferable to blend 450 to 2000 volume ppm with respect to the light oil composition.

  As the rust preventive agent, various rust preventive agents can be used, for example, monocarboxylic acid such as stearic acid, carboxylic acid such as dicarboxylic acid such as alkyl or alkenyl succinic acid; fatty acid, naphthenic acid, abietic acid, lanolin fatty acid, alkenyl Alkaline earth metal salts of carboxylic acids such as succinic acid and amino acid derivatives, various metal element salts such as aluminum, zinc and lead, carboxylates such as amine salts; petroleum sulfonic acid, dinonylnaphthalene sulfonic acid, heavy alkylbenzene sulfone Sulfonic acid salts such as alkali metal salts, alkaline earth metal salts and amine salts of sulfonic acids such as acids; polyhydric alcohols such as sorbitol, pentaerythritol, sucrose and glycerin and carboxylic acids such as oleic acid and lauric acid Carboxylic esters such as partial esters; higher aliphatics Alcohols such as alcohols; Amines such as cyclohexylamine, morpholine, alkoxyphenylamines, diethanolamine derivatives, amino alcohols, ethylene oxide adducts of rosinamines; oil-soluble surfactants having polar groups such as phosphoric acid as main or subpolar groups Is mentioned. Among these rust preventives, preferred are those having an ashless type amino group. These rust preventives may be used alone or in combination of two or more. Although the compounding quantity of a rust preventive agent should just be selected suitably, it is preferable to mix | blend 2-100 volume ppm with respect to a light oil composition.

  Various antifoaming agents can be used as the antifoaming agent, and examples thereof include silicone polymers such as polydimethylsiloxane, a copolymer of dimethylsiloxane and trifluoropropylmethylsiloxane, and a copolymer of dimethylsiloxane and oxyethylene. Preferably, a copolymer of dimethylsiloxane and oxyethylene is used. These antifoaming agents may be used individually by 1 type, and may be used in combination of 2 or more type. The blending amount of the antifoaming agent may be appropriately selected, but it is preferable to blend 3 to 20 ppm by volume with respect to the light oil composition.

  As the antioxidant, various antioxidants can be used, for example, amines such as N, N′-diisopropyl-p-phenylenediamine, N, N′-di-sec-butyl-p-phenylenediamine; Examples thereof include phenols such as 6-di-tert-butyl-4-methylphenol, 2,4-dimethyl-6-tert-butylphenol, and 2,6-di-tert-butylphenol. These antioxidants may be used individually by 1 type, and may be used in combination of 2 or more type. The blending amount of the antioxidant may be selected as appropriate, but it is preferable to blend 10 to 60 ppm by volume with respect to the light oil composition.

  As the metal deactivator, various metal deactivators can be used, and examples thereof include N, N'-disalicylidene-1,2-diaminopropane. These metal deactivators may be used alone or in combination of two or more. Although the compounding quantity of a metal deactivator should just be selected suitably, it is preferable to mix | blend 2-20 volume ppm with respect to a light oil composition.

  As the hue stabilizer, various hue stabilizers can be used, and examples thereof include alkenyl succinimide having a function as a detergent, other anthraquinones, hydrazine, and the like. These hue stabilizers may be used individually by 1 type, and may be used in combination of 2 or more type. The blending amount of the hue stabilizer may be appropriately selected, but it is preferable to blend 10 to 1000 ppm by volume with respect to the light oil composition.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited to a following example.

Example 1
A gas oil fraction (straight-run gas oil, distillation cut range 170 to 370 ° C.) obtained from Middle Eastern crude oil by atmospheric distillation is used as a raw material oil, and a commercial catalyst (Co-Mo system) is used as the hydrodesulfurization catalyst. The resulting mixture was hydrotreated to obtain a desulfurized gas oil composition. The properties are shown in Table 1.

Example 2
A gas oil fraction (straight-run gas oil, distillation cut range 170-380 ° C.) obtained by atmospheric distillation from Middle Eastern crude oil (however, the crude oil type is different from Example 1) is used as a raw oil, and the raw oil is hydrogenated. Hydrogenation treatment was performed using a commercially available catalyst (Co—Mo system) as a desulfurization catalyst to obtain a desulfurized light oil composition. The properties are shown in Table 1.

Example 3
The desulfurized gas oil composition obtained in Example 1 was kerosene fraction (straight-run kerosene, distillation cut range 160-370 ° C.) obtained by atmospheric distillation from Middle Eastern crude oil, and the raw oil was hydrogenated. A desulfurized gas oil composition was obtained by mixing 10% by volume of desulfurized kerosene (distillation cut range 150 to 350 ° C.) obtained by hydrogenation using a commercially available catalyst (Co—Mo system) as a desulfurization catalyst. The properties are shown in Table 1.

Example 4
Gas oil fraction obtained from Middle Eastern crude oil by atmospheric distillation (straight-run gas oil, distillation cut range 160-370 ° C) and light oil fraction obtained by vacuum distillation from Middle East crude oil (light vacuum gas oil, distillation cut range) 160% to 370 ° C) was mixed with 10% by volume as a raw material oil, and the raw material oil was hydrotreated using a commercially available catalyst (Co-Mo system) as a hydrodesulfurization catalyst to obtain a desulfurized gas oil composition. . The properties are shown in Table 1.

Example 5
Contact a light oil fraction obtained by atmospheric distillation from Middle Eastern crude oil (straight-run diesel oil, distillation cut range 170-360 ° C) with a higher boiling point fraction higher than that obtained by atmospheric distillation from Middle Eastern crude oil A mixture obtained by mixing 10% by volume of catalytic cracking light oil (LCO) obtained by cracking is used as a raw material oil, and the raw material oil is hydrotreated using a commercially available catalyst (Co-Mo system) as a hydrodesulfurization catalyst, A desulfurized gas oil composition was obtained. The properties are shown in Table 1.

Reference example 1
Gas oil fraction obtained from Middle Eastern crude oil by atmospheric distillation (straight-run gas oil, distillation cut range 170 ~
370 ° C.) as raw material oil, desulfurized light oil obtained by hydrotreating the raw material oil as a hydrodesulfurization catalyst using a commercially available catalyst (Co—Mo system), and having 30 or more carbon atoms obtained by Fischer-Tropsch synthesis After hydrocracking the wax content of the catalyst using a commercially available catalyst (Pt system) as a hydrocracking catalyst, 10% by volume of a light oil fraction (distillation cut range 200-350 ° C.) obtained by distillation is mixed to desulfurize A light oil composition was obtained. The properties are shown in Table 1.

Comparative Example 1
A gas oil fraction (straight-run gas oil, distillation cut range 170 to 360 ° C.) obtained from Middle Eastern crude oil by atmospheric distillation is used as a raw material oil, and a commercial catalyst (Co-Mo system) is used as the hydrodesulfurization catalyst. Hydrogenation treatment was performed to obtain a desulfurized gas oil composition. The properties are shown in Table 1.

Comparative Example 2
A desulfurized gas oil composition obtained by adding a predetermined amount of n-dodecyl mercaptan (manufactured by Tokyo Chemical Industry Co., Ltd., commercially available reagent) to the desulfurized gas oil composition obtained in Reference Example 1 and adjusting the sulfur content of the mercaptans to 2.2 mass ppm. Obtained. The properties are shown in Table 1.

About the light oil composition prepared by the said Example, reference example, and the comparative example, the copper plate corrosion test for 3 hours at 50 degreeC and the copper plate corrosion test for 24 hours at 149 degreeC were done. The results are shown in Table 1.
If the copper plate corrosion test result for 3 hours at 50 ° C is 2 or more, or if the copper plate corrosion test result for 24 hours at 149 ° C is 4 or more, corrosion will occur in the fuel injection system, which may affect the environment. It may become impossible to maintain precise operation control for reduction for a long time.

  As is clear from Table 1, in Comparative Example 1 in which the sulfur content of the sulfur compound heavier than n-decyl mercaptan (1-decanethiol) and lighter than dibenzothiophene exceeds 0.4 mass ppm, it is 24 hours at 149 ° C. The copper plate corrosion test worsens to 4. Moreover, it turns out that the copper plate corrosion test of 24 hours at 149 degreeC deteriorates to 4 also in the comparative example 2 in which the sulfur content of mercaptans exceeds 2 mass ppm.

Claims (5)

It contains a desulfurized gas oil composition obtained by subjecting a base material containing straight-run gas oil obtained from crude oil by atmospheric distillation to hydrogenation treatment, and satisfies the following properties (a) to (c) A light oil composition.
(A) 3-10 mass ppm of total sulfur content
(B) Among the total sulfur content, the sulfur content of mercaptans is 0.4-2 mass ppm.
(C) Among the total sulfur content, the sulfur content of the sulfur compound heavier than n-decyl mercaptan (1-decanethiol) and lighter than dibenzothiophene is 0.4 mass ppm or less. The gas oil composition according to claim 1, wherein the base material further contains at least one selected from desulfurized kerosene, light vacuum gas oil, and catalytic cracked gas oil. The gas oil composition according to claim 1, wherein the base material further contains desulfurized kerosene. 4. The hydrogenation treatment is performed on the base material using a Co—Mo, Ni—Mo, or Ni—Co—Mo catalyst at a temperature of 330 to 400 ° C. 5. 2. The light oil composition according to item 1. A base material containing straight-run gas oil obtained from crude oil by atmospheric distillation is hydrotreated with a Co-Mo, Ni-Mo, Ni-Co-Mo catalyst at a temperature of 330 to 400 ° C,
  (A) 3-10 mass ppm of total sulfur content
  (B) Among the total sulfur content, the sulfur content of mercaptans is 0.4-2 mass ppm.
  (C) Among the total sulfur content, the sulfur content of the sulfur compound heavier than n-decyl mercaptan (1-decanethiol) and lighter than dibenzothiophene is 0.4 mass ppm or less.
A process for producing a light oil composition, characterized in that the light oil composition is obtained.