JP4633352B2 - Fuel composition for diesel engines - Google Patents

Description

  The present invention provides a fuel composition for a diesel engine having rubber swellability suitable for a conventional diesel vehicle even when the content of a sulfur compound, an aromatic hydrocarbon compound or the like is reduced in order to reduce the influence on the environment. Related to things.

  In recent years, due to stricter exhaust gas regulations for automobiles, in order to reduce NOx and PM emitted from automobiles using diesel engines (diesel automobiles), it is mandatory to install exhaust gas purification devices mainly in urban areas. On the other hand, since the sulfur content of diesel fuel has a large adverse effect on the exhaust gas purification device, it is necessary to reduce this.

  In areas where exhaust gas purification equipment is not required, it is necessary to reduce PM causative substances. As one of the causative substances of PM, two or more polycyclic aromatic hydrocarbon compounds (hereinafter simply referred to as PM) Also referred to as “polycyclic aromatic”.

  In order to meet such a demand, reduction of the sulfur content of the fuel for diesel engines and reduction of the aromatic content, particularly the polycyclic aromatic content of two or more rings are required. For this purpose, hydrodesulfurization of petroleum-derived light oil fraction, which is a raw material for diesel engine fuel, is generally performed. When hydrodesulfurization is performed to such a level that the sulfur content is 10 mass ppm or less, aromatic compounds are decomposed at the same time, so that the aromatic content in the light oil fraction decreases.

  However, when the aromatic content is lowered, the rubber swelling property of the diesel fuel is remarkably lowered. Conventional diesel engine engines such as diesel automobiles are designed on the assumption that rubber swells due to diesel engine fuel using a synthetic rubber or the like for the fuel system. For this reason, when the rubber swelling property of diesel fuel is reduced, there is a concern about inconvenience in operation.

  This invention solves such a subject, and it aims at provision of the diesel fuel which has moderate rubber swelling property, even if it reduces a sulfur content and an aromatic content.

  As a result of intensive studies to solve the above problems, the present inventors have found that the rubber swelling property can be maintained by reducing the polycyclic aromatic content of light oil and making the aromatic content within a predetermined range. It was. Furthermore, it has been found that aromatics have a great influence on rubber swellability due to their substituents, and the present invention has been conceived from these results.

That is, the fuel composition for a diesel engine according to the present invention has (a) a sulfur content of 10 mass ppm or less, (b) a kinematic viscosity at 30 ° C. of 3.0 to 4.6 mm ² / s, and (c) a 10% retention. Outlet temperature is 200 to 250 ° C., (d) Flash point is 60 ° C. or more, (e) Density is 0.82 g / cm ^{3 to} 0.84 g / cm ³ , (f) Total aromatic content is 10% by volume or more, 24% by volume or less, (g) 3% by volume or less of the aromatic content of two or more rings, and (h) the proportion (% by mass) of hydrogen derived from the aromatic ring in the total hydrogen contained in the total aromatic content. , The proportion Hα of hydrogen bonded to the α-position carbon of the substituent of the aromatic ring in the total hydrogen contained in the total aromatic content, the proportion Hβ of hydrogen bonded to the β-position carbon, and the bond to the carbon at the γ-position or higher (Ha, Hα, Hβ, Hγ) of the hydrogen ratio Hγ is (15.6, 33.1, 37.0, 14.3), (15.4, 36.9, 35. , 12.2), is of the (15.4,30.7,39.0,14.9) or (15.5,37.3,35.4,11.8). In particular, the aromatic content of 9 carbon atoms is preferably 2% by volume or more.

  According to the present invention, since the polarity index and the like are set in a predetermined range, when the sulfur content is 10 mass ppm or less and the sulfur content is extremely low, and the aromatic content of two or more rings is 4 vol% or less. However, a fuel composition for a diesel engine having an appropriate rubber swelling property can be obtained, and even if it is used in a conventionally used diesel engine engine, the fuel system is not hindered.

[Density] fuel for diesel engines according to the present invention has a density of 0.82 g / cm ³ or more, preferably 0.82~0.84g / cm ^3.
[Sulfur content] The diesel engine fuel according to the present invention has a sulfur content of 10 ppm by mass or less, preferably 6 ppm by mass or less.
[Kinematic Viscosity] The diesel engine fuel according to the present invention preferably has a kinematic viscosity at 30 ° C. of 2.0 to 4.7 mm ² / s, particularly 3.0 to 4.6 mm ² / s.
[Distillation Properties] The diesel engine fuel according to the present invention has a 10% distillation temperature of 190 ° C. or higher, preferably 190 to 260 ° C., particularly preferably 200 to 250 ° C. The 90% distillation temperature is preferably 260 to 360 ° C, particularly preferably 280 to 350 ° C. The distillation amount at 220 ° C. or lower is preferably 3% or more, particularly 5 to 15%.
[Flash point] The flash point of the diesel engine fuel according to the present invention is 60 ° C or higher.
[Aromatic Content] The diesel engine fuel according to the present invention has a total aromatic content of 10 to 24% by volume, preferably 15 to 24% by volume. The aromatic content of two or more rings is 4% by volume or less, preferably 3% by volume or less. The aromatic content of three or more rings is preferably 1% by volume or less, particularly preferably 0.6% by volume or less. Moreover, it is preferable that the aromatic component having 9 carbon atoms is 2% by volume or more, particularly 2 to 6% by volume.
[Polarity index]
The diesel engine fuel according to the present invention has a polarity index PI of 202-208, preferably 204-206. Here, PI = 0.2 × (total aromatic content) + 3.2 × Ha + 1.8 × Hα + 1.9 × Hβ + 1.4 × Hγ, and Ha is the aromatic that occupies the total hydrogen contained in the total aromatic content. The proportion of hydrogen derived from the ring (mass%), Hα, Hβ, and Hγ are the proportion of hydrogen derived from the substituent of the aromatic ring in the total hydrogen contained in the total aromatic content, and each of the α positions of the substituent , Corresponding to the proportion of hydrogen bonded to carbon at the β-position and γ-position or higher.

  A general calculation method of Ha, Hα, Hβ, and Hγ is based on a proton / magnetic resonance spectrum (NMR). The peaks of hydrogen bonded to the aromatic ring in the total aromatic component and carbons at the α-position, β-position, and γ-position or higher of the aromatic ring substituent are 9.2 to 6.0 ppm and 4.17 to 2, respectively. Appears at .00 ppm, 2.00 to 1.00 ppm and 1.00 to 0.50 ppm. Therefore, Ha, Hα, Hβ, and Hγ can be calculated by using the respective integral values as a percentage of hydrogen at each site according to the following relational expression.

Ha = (integrated value derived from aromatic ring) / (total integrated value) × 100
Hα = (integral value of α position from aromatic ring) / (total integrated value) × 100
Hβ = (integral value of β-position from aromatic ring) / (total integrated value) × 100
Hγ = (integral value of γ position or more from the aromatic ring) / (total integrated value) × 100

[Characteristics of fuel]
In general, the light oil must have a quality satisfying at least JIS K 2204 “light oil”, and the fuel for the diesel engine according to the present invention is added to the above-specified properties in addition to JIS K 2269 “ Pour point of crude oil and petroleum product and pour point of petroleum product cloud point ", clogging point of JIS K 2288" light oil-clogging point test method ", JIS K 2270" crude oil and petroleum product-residual carbon content test method " And the properties of cetane index, etc. according to JIS K 2280 “Petroleum products—fuel oil—octane number and cetane number test method and cetane index calculation method” may also satisfy the above JIS K 2204 regulations. preferable.
[Method for producing fuel]
The base material used for preparing the fuel composition for a diesel engine of the present invention includes a straight-run gas oil obtained from a crude oil atmospheric distillation device, a vacuum gas oil obtained from a vacuum distillation device, and a crude oil atmospheric distillation device. Straight-run kerosene obtained from a catalytic cracker, catalytically cracked diesel oil obtained from a catalytic cracker, degasified oil obtained from a heavy oil indirect desulfurizer, direct degasified diesel oil obtained from a heavy oil direct desulfurizer, etc. Substrates subjected to purification treatment such as hydrodesulfurization, isomerization and dewaxing are preferred. A plurality of base materials obtained from the petroleum refining process can be mixed and used. Furthermore, as a base material, a base material derived from a hydrocarbon synthesized by Fischer-Tropsch method using natural gas, coal or the like as a raw material can be used.

  The sulfur content, the total aromatic content, the aromatic content of two or more rings, and the polarity index can calculate values when a plurality of base materials are blended by measuring each base material. In particular, it is preferable that 2 to 10% by volume, particularly 3 to 7% by volume of an aromatic hydrocarbon having 9 carbon atoms is blended in the light oil fraction. The light oil fraction used for this has a 10% distillation temperature of 200 to 270 ° C, particularly preferably 240 to 270 ° C, and a 90% distillation temperature of 300 to 350 ° C, particularly 310 to 340 ° C.

  In order to prepare the diesel engine fuel of the present invention, vegetable oil methyl ester or the like can be used as another light oil base. In addition, as fuel additives for diesel engines, known fuel additives such as low-temperature fluidity improvers, wear resistance improvers, cetane number improvers, antioxidants, metal deactivators, and corrosion inhibitors are used. It may be added. As the low temperature fluidity improver, an ethylene copolymer or the like can be used, and in particular, a vinyl ester of a saturated fatty acid such as vinyl acetate, vinyl propionate or vinyl butyrate is preferably used. As the wear resistance improver, a long chain (for example, having 12 to 24 carbon atoms) fatty acid or fatty acid ester is preferably used. Abrasion resistance is sufficiently improved with an addition amount of 10 to 500 ppm by mass, preferably 50 to 150 ppm by mass.

The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples.
[Light oil base 1 to 4]
In the following examples and comparative examples, light oil bases 1 to 4 having properties shown in Table 1 were used.

The light oil base material 1 is a commercial catalyst HOP-467 (supporting Ni, Mo and P as a catalyst) using a mixed oil of a straight-run light oil fraction obtained by atmospheric distillation of Middle Eastern crude oil and a catalytic cracked light oil fraction as a catalyst. (Registered trademark, manufactured by ART K.K.) was used for hydrorefining at a reaction temperature of 380 ° C., a reaction pressure of 5.0 MPa, a hydrogen / oil ratio of 250 NL / L, and LHSV of 2.0 hr ⁻¹ to separate a light oil fraction. It is a thing that was retained.

The light oil base material 2 is a commercially available catalyst HOP-461 (registered trademark, manufactured by ART K.K.) carrying Ni, Mo and P as catalysts from a straight-run kerosene fraction obtained by atmospheric distillation of Middle Eastern crude oil. The kerosene fraction was fractionated by hydrorefining at a reaction temperature of 300 ° C., a reaction pressure of 3.5 MPa, a hydrogen / oil ratio of 170 NL / L, and LHSV of 4.0 hr ⁻¹ .

The light oil base material 3 is a commercially available catalyst HOP-414 (registered trademark, manufactured by ART K.K.) carrying Ni, Mo and P as catalysts from a straight-run light oil fraction obtained by atmospheric distillation of Middle Eastern crude oil. The gas oil fraction is fractionated by hydrorefining at a reaction temperature of 330 ° C., a reaction pressure of 6.5 MPa, a hydrogen / oil ratio of 350 NL / L, and LHSV of 1.0 hr ⁻¹ .

The light oil base material 4 is a commercially available catalyst HOP-414 (supporting Ni, Mo and P as a catalyst) using a mixed oil of a straight-run light oil fraction obtained by atmospheric distillation of Middle Eastern crude oil and a pyrolysis light oil fraction as a catalyst. (Registered trademark, manufactured by ART K.K.) was used for hydrorefining at a reaction temperature of 310 ° C., a reaction pressure of 6.5 MPa, a hydrogen / oil ratio of 350 NL / L, and a LHSV of 0.5 hr ⁻¹ to separate a light oil fraction. It is a thing that was retained.

  A commercially available reagent was used for propylbenzene.

  Further, the aromatic component having 9 carbon atoms was subjected to qualitative analysis / quantitative analysis by a GCMS method (GC-MS apparatus: HP-6890 (manufactured by Agilent Technology)).

  In addition, as for each physical property, the density is JIS K 2249, the sulfur content is JIS K 2541, the kinematic viscosity (30 ° C.) is JIS K 2283, the distillation property is JIS K 2254, the flash point is JIS K 2265, and the aromatic content is the Japan Petroleum Institute. Method JPI-5S-49-97, the volume change rate, which is a rubber swelling property, was measured according to JIS K 6258 using NBR as rubber.

The total aromatic content in each light oil was extracted by open column chromatography. The extraction conditions are as follows.
〔Extraction condition〕
Silica gel: Grade 923 (Fuji Silysia Chemical Ltd.)
140 ° C. × 5 hours Aging sample 20 g dissolved in 20 ml of n-hexane was developed on the silica gel, and then the saturated content was removed using 200 ml of n-hexane. Further, the total aromatic content was extracted using 200 ml of methylene chloride. The solvent was removed from the obtained extracted solution while purging with a 60 ° C. bath with nitrogen to obtain a total aromatic content.

  Ha, Hα, Hβ, and Hγ were calculated by measuring the total aromatic content extracted by open column chromatography using proton NMR (manufactured by JEOL Ltd., GSX-270 type NMR apparatus, 270 MHz).

〔実施例１〜３、比較例１〜２〕
これらの軽油基材１〜４およびプロピルベンゼンを表２の上部に示す配合量で配合し、実施例１〜３、比較例１〜２の軽油を調製した。調製された軽油の性状を表２に併せて示す。

[Examples 1-3, Comparative Examples 1-2]
These light oil base materials 1 to 4 and propylbenzene were blended in the blending amounts shown in the upper part of Table 2, and light oils of Examples 1 to 3 and Comparative Examples 1 to 2 were prepared. The properties of the prepared light oil are shown together in Table 2.

実施例１〜４のように極性指数を２０４〜２０５とすることで、ゴム膨潤性における体積変化率を６〜９容量％とすることができることがわかる。比較例１では極性指数が２１２、かつ引火点が６０℃以下となり、また、比較例２、３では極性指数が各々２０１となりゴム膨潤性が悪化することがわかる。

It turns out that the volume change rate in rubber swellability can be made 6-9 volume% by making a polarity index into 204-205 like Examples 1-4. It can be seen that Comparative Example 1 has a polarity index of 212 and a flash point of 60 ° C. or lower, and Comparative Examples 2 and 3 each have a polarity index of 201, which deteriorates rubber swellability.

According to the present invention, since the polarity index and the like are set in a predetermined range, when the sulfur content is 10 mass ppm or less and the sulfur content is extremely low, and the aromatic content of two or more rings is 4 vol% or less. However, a fuel composition for a diesel engine having an appropriate rubber swelling property can be obtained, and even if it is used in a conventionally used diesel engine engine, the fuel system is not hindered.

Claims (2)

(A) Sulfur content is 10 mass ppm or less, (b) Kinematic viscosity at 30 ° C. is 3.0 to 4.6 mm ² / s, (c) 10% distillation temperature is 200 to 250 ° C., (d) Flash point. There 60 ° C. or higher, (e) density of ^{0.82g / cm 3 ~0.84g / cm 3} , (f) a total aromatic content of 10 vol% or more, 24% by volume, (g) a bicyclic or more aromatic 3% by volume or less of the group and (h) the proportion of hydrogen derived from the aromatic ring in the total hydrogen contained in the total aromatic content (mass%) Ha, the fragrance in the total hydrogen contained in the total aromatic content The ratio Hα of hydrogen bonded to the α-position carbon of the substituent of the group ring, the ratio Hβ of hydrogen bonded to the β-position carbon, the ratio Hγ of hydrogen bonded to carbons of the γ-position and higher (Ha, Hα, Hβ, Hγ) is (15.6, 33.1, 37.0, 14.3), (15.4, 36.9, 35.5, 12.2), (15.4, 30.7, 39). 0.0, 14.9) or ( 15.5, 37.3, 35.4, 11.8) fuel composition for diesel engines.
  The fuel composition for a diesel engine according to claim 1, wherein the aromatic component having 9 carbon atoms is 2% by volume or more.