JPH08199178A - Diesel fuel - Google Patents

Abstract

(57) [Summary] [Purpose] A diesel fuel that can significantly reduce pollutants in exhaust gas, does not deteriorate in combustibility even when water is mixed, and has sufficient lubricity even if S content is reduced. provide. [Composition] Unsaturated dicarboxylic acid diester was added to diesel fuel.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a diesel fuel composition obtained by adding a specific oxygen-containing compound to a gas oil fraction.

[0002]

2. Description of the Related Art A diesel engine has good fuel efficiency, low fuel cost, and a tough engine. Therefore, it is installed in trucks, buses, ships, construction machinery, etc. It tends to increase. But,
Exhaust gas from a diesel engine contains hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NO).
x), sulfurous acid gas (SOx), black smoke, and other air pollutants are contained, and there is an urgent need to reduce them from the viewpoint of preventing environmental pollution.

At present, as a measure for reducing the particulate matter which is the source of black smoke, a method has been proposed in which a filter is provided in the middle of the exhaust pipe to collect and burn, but it is difficult to control combustion. It has not been put to practical use. Furthermore, a method of mixing (adding) a base material composed of an oxygen-containing compound such as alcohol or acetal is being studied (SAE pa
per 930728, 1993), these compounds are currently proposed, but these compounds have low solubility in light oil fractions, emulsification due to the inclusion of water to reduce the flammability, or transfer of oxygen-containing compounds to the water layer. Then, there is a problem that the effect disappears or the cetane number is lowered to deteriorate the combustibility.

Further, it has been studied to make the sulfur content in diesel fuel sufficiently low, for example, 0.05% by weight or less. As a result, the concentration and total amount of sulfurous acid gas released into the atmosphere can be reduced. However, in recent years, in Northern Europe and the west coast of the United States, where eco-friendly diesel fuels having a low sulfur content have begun to be sold, there have been problems with diesel vehicles that are thought to be due to lack of lubrication characteristics of the fuels.
Particularly, there is a concern that a trouble such as wear and seizure of parts of a fuel injection pump of a diesel engine, which conventionally relies on fuel for lubrication of a boundary lubrication portion, frequently occurs.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above problems, and an object of the present invention is to significantly reduce pollutants in exhaust gas and also to improve the combustibility by emulsification even when water is mixed. Diesel that does not decrease, does not reduce the effect by moving to water mixed with a base material composed of an oxygen-containing compound and disappears, and has sufficient lubricating properties even when the sulfur content is reduced. It provides fuel.

[0006]

Means for Solving the Problems As a result of intensive research to solve the above problems, the present inventors have found that unsaturated dicarboxylic acid diesters are soluble in gas oil fractions and have low solubility in water. It is rarely distributed to the water layer in the mixed layer of light oil fraction and water, and has a cetane number that can be put to practical use. When added to the light oil fraction and burned, pollutants in exhaust gas are greatly reduced. The inventors have found that they can do so and have reached the present invention. That is, the diesel fuel of the present invention contains an unsaturated dicarboxylic acid diester.

The unsaturated dicarboxylic acid diester used in the present invention is preferably an unsaturated dicarboxylic acid diester represented by the following general formula (1).

Embedded image (In the formula, R ¹ and R ² are hydrogen or an alkyl, aryl, or aralkyl group having 1 to 1 carbon atoms, and R ³ and R ⁴ are 1 to 1 carbon atoms.
Is an alkyl, aryl or aralkyl group. ) The compound of the above formula (1) has the following general formula (2)

Embedded image (In the formula, R ¹ and R ² are the same as the above), which is a diester obtained by an esterification reaction of a dicarboxylic acid and an alcohol.

R ¹ and R ² in the general formula (2) represent hydrogen or alkyl having 1 to 20 carbon atoms, aryl or aralkyl. More preferably, it is an alkyl group having 1 to 10 carbon atoms, and even more preferably, an alkyl group having 1 to 4 carbon atoms, that is, methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, s-. Butyl and t-butyl. Particularly preferable examples of the dicarboxylic acid represented by the general formula (2) include maleic acid and fumaric acid.

The hydrocarbon group R ³ or R ⁴ of the alcohol component which reacts with these acids to form the unsaturated dicarboxylic acid diester of the general formula (1) has 1 to 2 carbon atoms.
0 alkyl, aryl and aralkyl. More preferably, it is an alkyl group having 1 to 10 carbon atoms, and even more preferably an alkyl group having 1 to 4 carbon atoms, that is, methyl,
Ethyl, n-propyl, i-propyl, n-butyl, i
-Butyl, s-butyl, t-butyl. Particularly preferred unsaturated dicarboxylic acid diesters used in the present invention are those in which R ¹ and R ² are hydrogen or a methyl group and R ³ and R ^{4 are}
Examples thereof include dimethyl maleate in which is a methyl or ethyl group, diethyl maleate, dimethyl fumarate, diethyl fumarate and the like. These are preferable because they are rarely distributed to the water layer in the mixed layer of the light oil fraction and water. Further, the boiling point of the unsaturated dicarboxylic acid diester used in the present invention is preferably in the range of 150 to 400 ° C. from the viewpoint of volatility when injected into the diesel engine. Furthermore, it is preferable to use a dialkyl maleate as the unsaturated dicarboxylic acid dialkyl, particularly dimethyl maleate or methyl ethyl maleate, since it is easily available and inexpensive.

In the present invention, the dicarboxylic acid diester is 0.001 to 5.0% by weight based on the diesel fuel.
It can be used in a range of. Especially 0.5 to 3% by weight
It is preferable to contain, and it is more preferable to contain 1 to 3% by weight. If it is less than 0.01% by weight, the reduction of the particulates is not sufficient, and if it exceeds 5.0% by weight, the solubility in the gas oil fraction may decrease, which is not preferable. Further, in the case of diesel fuel having a sulfur content of 0.07% by weight or less, by containing the dialkyl unsaturated dicarboxylate, light oil in which trace components such as sulfide having lubricity have been almost removed by severe hydrodesulfurization. Sufficient lubricating characteristics can be obtained even when a distillate is used. Diesel fuel having a sulfur content of 0.07% by mass or less is usually a diesel fuel base material obtained by hydrodesulfurizing a sulfur content to 0.1% by mass or less and another base material having a sulfur content of 0.05% by mass or less. It is obtained by blending. As a gas oil base material that has been hydrodesulfurized to a sulfur content of 0.1% by mass or less, deep-desulfurized straight-run gas oil obtained from a crude oil atmospheric distillation device can be used as a straight-run gas oil or crude oil atmospheric distillation device. Deep-desulfurized after blending straight-run kerosene obtained from, catalytic cracking gas oil by-produced from the catalytic cracker, direct degassed light gas oil by-produced from heavy oil direct desulfurization equipment, and those with hydrocracked oil blended Etc. can be used. The deep desulfurization device, process and operating conditions for hydrodesulfurizing the sulfur content to 0.1% by mass or less are not particularly limited, and any known deep desulfurization device, process or the like may be used in appropriate combination. You can

The dialkyl unsaturated dicarboxylic acid can be easily produced by reacting an unsaturated dicarboxylic acid with an alcohol to esterify the unsaturated dicarboxylic acid. In particular, dimethyl maleate can be produced industrially at low cost by first obtaining maleic acid or maleic anhydride from butane, butene, butadiene, benzene and the like as a raw material and esterifying it with methanol.

The present invention comprises mixing (or adding) the above-mentioned unsaturated dialkyl dicarboxylate to a gas oil fraction. This gas oil fraction is a petroleum fraction used as a fuel for diesel engines. , For example, the boiling point is 1
At 80 to 380 ° C., the above compound is added to JIS K2
Those having a specification of No. 1, No. 1, No. 2, No. 3, or No. 3 light oil specified in No. 204 are preferably used. In addition, in the diesel engine fuel of the present invention, in addition to the unsaturated dicarboxylic acid dialkyl,
Known fuel additives such as a cetane number improver, an antioxidant, a metal deactivator and a corrosion inhibitor may be added.

[0013]

【Example】

(Measurement of Cetane Number) The cetane number of a diesel fuel obtained by mixing a light oil fraction having the properties shown in Table 1 and 2% by weight of dimethyl maleate was measured using a CFR engine according to JIS K2280.
It was measured by the method specified in 1. As a result, the cetane number is 5
It was 2.7, and from this, the cetane number of dimethyl maleate itself was estimated to be 36.

[0014]

[Table 1] Density (15 ° C) [g / cm ² ] 0.8426 Kinematic viscosity (30 ° C) [cSt] 3.859 Cetane number 53.1 Pour point [° C] -10.0 Cloud point [° C]- 9.0 Sulfur content [wt%] 0.05 Distillation property [° C] IBP 181.5 5% 227.0 50% 273.0 95% 331.0 EP 341.0

(Combustion test) A combustion test was conducted on a diesel fuel in which a gas oil fraction having the properties shown in Table 1 and 2% by weight of dimethyl maleate were mixed. Diesel vehicle I3 mode exhaust gas and particulate matter test method using the direct injection diesel engine shown in Table 2 (TRIAS 23-1992)
Particulate in the exhaust gas [collected by the mini dilution system (manufactured by Horiba, Ltd.)] according to
HC, CO, NOx [Automobile exhaust gas measurement device MEXA
-8120D, manufactured by Horiba Ltd.] was measured. The results are shown in Table 2 as the rate of change with respect to the case where the fuel having only the gas oil fraction having the properties shown in Table 1 (comparative fuel) was used. It was found that the particulate matter and CO were clearly reduced. It should be noted that + (positive value) indicates an increase over the comparative fuel, and- (negative value) indicates an decrease over the comparative fuel.

[0016]

[Table 2] Engine type Supercharged direct injection engine Water-cooled 6 single cylinder Displacement 6000cc Intake system Single valve output 42kg / 1800r. p. m. Idling speed 550r. p. m.

[0017]

[Table 3] Particulate -4% HC + 2% CO -4% NOx -2%

(Abrasion resistance test) An abrasion resistance test of a diesel fuel in which a light oil fraction having the properties shown in Table 1 and 0.5% by weight of dimethyl maleate were mixed was carried out by the abrasion mark diameter of the test bottle. When the addition amount was 0.5% by weight, it was 5.9 mm. For comparison, a wear resistance test of a fuel having only the light oil fraction having the properties shown in Table 1 was also performed, and the wear scar diameter was 7.9 mm.
Met. The wear scar diameter of the test bottle was measured by the Farex wear test method (ASTM D2670). Table 4 shows the main test conditions.

[0019]

[Table 4] Pin material: Iron Block material: Iron Test oil temperature: 30 ° C Rotation speed: 290r. p. m. Load: 200 lb Test time: 30 minutes

[0020]

INDUSTRIAL APPLICABILITY The diesel fuel of the present invention can significantly reduce atmospheric pollutants such as carbon monoxide and sulfurous acid gas in exhaust gas, and further reduce the combustibility due to emulsification and the inclusion of oxygen-containing compounds even when water is mixed. It has a special effect such as no reduction in the effect due to disappearance. In addition, even when the sulfur content is reduced, it has sufficient lubricating characteristics.

Claims (5)

[Claims] 1. Diesel fuel containing an unsaturated dicarboxylic acid diester. 2. A diesel fuel containing an unsaturated dicarboxylic acid diester represented by the following general formula (1). Embedded image (In the formula, R ¹ and R ² are hydrogen or an alkyl, aryl or aralkyl group having 1 to 20 carbon atoms, and R ³ and R ⁴ are 1 to 1 carbon atoms.
20 alkyl, aryl and aralkyl groups. ) 3. The diesel fuel according to claim 2, wherein the unsaturated dicarboxylic acid dialkyl is dimethyl maleate. 4. A diesel fuel comprising dimethyl maleate in an amount of 0.001 to 5.0% by weight based on 100% by weight of diesel fuel. 5. The diesel fuel according to claim 1, which has a sulfur content of 0.07% by weight or less.