JPH0940975A - Fuel oil - Google Patents

Abstract

(57) [Summary] [Constitution] The fuel oil of the present invention is a gas oil fraction having a sulfur content of 0.05% by weight or less and a content of aromatic hydrocarbons of two or more rings of 3. 5% to 15% by weight,
In the aromatic hydrocarbon of two or more rings, the proportion of the aromatic hydrocarbon of two or more rings having a side chain alkyl group having 3 to 11 carbon atoms is 80% by weight or more. Characterize. [Effect] The fuel oil of the present invention is used as a diesel fuel.
Without adding additives such as antiwear agents, it is possible to impart antiwear properties by simply adjusting the gas oil component.
It is a fuel oil that has excellent storage stability and is inexpensive.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a diesel fuel oil having a low sulfur content and excellent lubricity.

[0002]

2. Description of the Related Art A diesel engine has better fuel economy than a gasoline engine, has a lower fuel cost, and has a tougher engine. Therefore, it is installed in trucks, buses, ships, construction machinery, etc. As a result, the amount tends to increase year by year.

However, sulfur contained in light oil (diesel fuel) poses a particularly serious social problem, and at the Central Pollution Council held in December 1989, a short-term goal for light oil was 1994. Sulfur content 0.2
It has been inquired to set the content to be not more than 10% by weight, and in the long term, to make it not more than 0.05% by weight, aiming at 1998, and its low sulfur content is an urgent issue.

In general, reduction of sulfur in light oil is achieved by refining treatment, particularly catalytic hydrogenation, but reduction of sulfur in light oil leads to deterioration of lubricity of light oil itself, resulting in deterioration of injection device of diesel engine. It causes a problem of causing damage. In particular, when the sulfur content is 0.2% by weight or less, the injection pump (particularly the rotary pump and the pump injector) is worn, and the wear amount increases in proportion to the decrease in the sulfur amount. for that reason,
For example, it is known to add an antiwear agent such as a fatty acid ester, but those to which these additives are added have the problems of being expensive and having poor storage stability.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel oil having excellent wear resistance by specifying the properties of a gas oil fraction without adding an antiwear agent.

[0006]

The fuel oil of the present invention is a gas oil fraction, has a sulfur content of 0.05 wt% or less, and is an aromatic hydrocarbon having two or more rings (hereinafter, polycyclic aromatic hydrocarbons). (Referred to as “group hydrocarbon”) is 3.5 wt% to 15 wt%, and the number of carbon atoms in the polycyclic aromatic hydrocarbon is 3 to
It is characterized in that the proportion of polycyclic aromatic hydrocarbons having 11 side chain alkyl groups (referred to as long-chain alkyl-substituted polycyclic aromatic hydrocarbons) is 80% by weight or more.

The fuel oil of the present invention is a gas oil fraction obtained by distilling crude oil, particularly paraffinic and mixed crude oil under atmospheric pressure, and hydrorefining the crude oil. The 90% distillation point is 350 ° C. or lower. It has a distillation property of (boiling point and distilling point according to JIS K 2254) and satisfies the light oil standard defined in JIS K2204.

The fuel oil of the present invention satisfies this standard and has a sulfur content of 0.05% by weight or less and a polycyclic aromatic hydrocarbon content of 3.5% by weight to 15% by weight. The proportion of the long-chain alkyl-substituted polycyclic aromatic hydrocarbon in the polycyclic aromatic hydrocarbon is 80% by weight or more.

The content of aromatic hydrocarbons in the light oil is usually 20% by weight after the hydrogenation operation, although it depends on the degree of the content.
-30% by weight, of which 12% to 27% by weight of monocyclic compounds and 2% to 15% by weight of polycyclic compounds. In the fuel oil of the present invention, the content of polycyclic aromatic hydrocarbons in the light oil is 3.5% by weight to 15% by weight,
It is preferably 3.5% by weight to 10% by weight. If the content of polycyclic aromatic hydrocarbons exceeds 15% by weight, the particulate matter in the exhaust gas increases, which is not preferable, and if it is less than 3.5% by weight, the wear resistance is poor.

Regarding the distribution of the substituted alkyl groups by the number of carbon atoms, the one having 5 to 7 side chain alkyl groups has a peak (the ratio is 35% by weight to 50% by weight), and shows a substantially normal distribution shape. Those having a substituted alkyl group having 1 to 2 carbon atoms occupy approximately 5% by weight to 15% by weight in the aromatic hydrocarbon having a substituted alkyl group. Also, those having 12 or more carbon atoms are rarely present in ordinary diesel oil.

In the fuel oil of the present invention, the preferred number of carbon atoms in the side chain alkyl group is 3 to 11, with less than 3 no effect on lubricity, and more than 11 results in thermal effects. Becomes unstable.

The polycyclic aromatic hydrocarbon has 3 carbon atoms.
It contains 80% by weight or more, and preferably 90% by weight or more of those having 1 to 11 alkyl groups as side chain substituents. Thereby, even if the sulfur content is 0.05% by weight or less, a gas oil having excellent lubricity can be obtained.

Although the detailed reason for this is unclear, since monocyclic aromatic hydrocarbons have a small van der Waals force of the aromatic ring, there is little interaction between the molecules under high load, and the alkyl group is substituted. It is presumed that even if it has a base, it hardly contributes to the lubricity of light oil. On the other hand, as the polycyclic aromatic hydrocarbon, a long-chain alkyl-substituted polycyclic aromatic hydrocarbon is
It is considered that those containing 0% by weight or more have strong intermolecular interaction under high load and have high viscosity due to entanglement, and it is presumed that the lubricity can be excellent. In addition, it is presumed that the length of the side chain substituent is more affected by the length than the number thereof.

The content of polycyclic aromatic hydrocarbons in the gas oil and the carbon number distribution of the side chain alkyl group were measured using 5 g of gas oil as a sample,
After extracting the saturated component with n-hexane, column chromatographic separation [chromatography tube: 25 mmf × 900 mm, chromatogel: silica gel (Fuji Serial Chemical # 12) 200 g
(40 g / g sample), solvent: 600 ml of toluene (3 m
1 / g gel)] to obtain the aromatic component by mass spectrometry (ionization method: FI).

The gas oil composition obtained by the hydrodesulfurization operation is, for example, (1) sulfur content: 0.2% by weight, content of polycyclic aromatic hydrocarbons: 3.5% by weight: 2-ring aromatic Hydrocarbon content: 2.9 wt% Long-chain alkyl-substituted polycyclic aromatic hydrocarbons in polycyclic aromatic hydrocarbons: Proportion of 60 wt%, (2) Sulfur content: 0.01 Weight% Polycyclic aromatic hydrocarbon content ・ ・ 1.7% by weight Bicyclic aromatic hydrocarbon content ・ ・ 1.5% by weight Long-chain alkyl-substituted polycyclic aromatic hydrocarbon in polycyclic aromatic hydrocarbon The proportion of hydrocarbons: 75% by weight.

To produce the fuel oil of the present invention, for example,
It is prepared by appropriately mixing hydrogenated light oil with light oil having a high aromatic hydrocarbon content. As the rich aromatic component, for example, catalytically cracked gas oil obtained by catalytically cracking heavy oil which is a straight-run component of crude oil may be used.

If desired, a pour point depressant, a cetane number improver, etc. may be added to the fuel oil of the present invention.

[0018]

INDUSTRIAL APPLICABILITY The fuel oil of the present invention is capable of imparting abrasion resistance only by adjusting the gas oil component without adding additives such as antiwear agents, and is excellent in storage stability. At the same time, it can be made into inexpensive fuel oil.

[0019]

EXAMPLES The abrasion resistance test adopted in the examples will be described.

The wear resistance test adopted in the present invention is ISO /
High frequency reciprocating rig device (HFR) specified by TC 22 / SC7 N595.
R, manufactured by PCS Co., Ltd.) and used to measure the wear scar diameter (μm) under the following test conditions. According to this measuring method, light oil having excellent wear resistance has a small wear scar diameter, and conversely, light oil having poor wear resistance has a large wear scar diameter.

Liquid volume 1 ± 0.20 ml Stroke length 1 ± 0.02 mm Frequency 50 ± 1 Hz Liquid temperature 25 ± 2 ° C. or 60 ± 2 ° C. Load 200 g Test time 75 ± 0.1 min Liquid surface area 6 ± 1 cm ² ( Example 1) A gas oil fraction having high aromaticity was mixed with a gas oil fraction obtained by atmospheric distillation of crude oil and desulfurized to a sulfur content of up to 0.05% by weight, and described in Table 1 below. A gas oil fraction having the above properties and composition was obtained and used as the sample oil 1 which is the fuel oil of the present invention.

Example 2 A light oil fraction obtained by atmospheric distillation of crude oil and desulfurized to a sulfur content of up to 0.05% by weight was processed in the same manner as in Example 1 to adjust aromatic components. ,
A gas oil fraction having the properties and composition shown in Table 1 below was obtained and used as a sample oil 2 as the fuel oil of the present invention.

Example 3 A comparative oil 1 of Table 1 below, which was obtained by atmospheric distillation of crude oil and desulfurized to a sulfur content of 0.01% by weight, was supplemented with isopropylnaphthalene of 0.1%.
8 wt% and ditert-butylnaphthalene were added so as to have a content of 1.0 wt% to obtain a gas oil fraction having the following properties and composition. Sample oil 3 as the fuel oil of the present invention
I got

(Comparative Example 1) The light oils listed in Table 1 below were
Comparative oil 1 was used.

(Comparative Example 2) A gas oil fraction obtained by atmospheric distillation of crude oil and desulfurized to a sulfur content of up to 0.2% by weight and having the properties and compositions shown in Table 1 below. The light oil fraction was designated as Comparative Oil 2.

Sample oils 1-3 prepared above and comparative oils 1-
For No. 2, an abrasion resistance test was performed at 60 ° C. The results are also shown in Table 1 below.

[0027]

[Table 1]

As can be seen from the table, the fuel oil of the present invention is
It can be seen that it has excellent wear resistance.

Claims (1)

[Claims] 1. A light oil fraction having a sulfur content of 0.0
5% by weight or less and the content of aromatic hydrocarbons having 2 or more rings is 3.5% by weight to 15% by weight, and the number of carbon atoms in the aromatic hydrocarbons having 2 or more rings is 3 A fuel oil characterized in that the proportion of aromatic hydrocarbons having two or more rings and having 11 to 11 side chain alkyl groups is 80% by weight or more.