JP3312056B2 - Low-pollution fuel oil for diesel engine and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-pollution fuel oil for diesel engines capable of reducing air pollutants such as particulates and nitrogen oxides in combustion exhaust gas, and a method for producing the same.

[0002]

2. Description of the Related Art Diesel engines are used in trucks, buses, ships, construction machines, etc. because of their good fuel economy, low fuel cost, and robust engine. It is increasing.

[0003] Currently, this diesel engine fuel oil is produced mainly by hydrodesulfurizing a straight-run gas oil fraction and blending it with various petroleum fraction base materials.

[0004] However, the combustion exhaust gas using this fuel oil contains relatively large amounts of air pollutants such as particulates, which are the main cause of black smoke, and nitrogen oxides (NO _x ), which cause acid rain. From the standpoint of global environmental protection, reduction of these air pollutants is urgently required.

[0005] Particulates in the exhaust gas of a diesel engine can be reduced by reducing the sulfur content in the fuel, and studies on reducing the sulfur in the fuel have been made.
As a measure for reducing sulfur, there is a method of performing hydrodesulfurization under severe conditions, for example, increasing the reaction temperature or lengthening the reaction time. However, this method has the disadvantage that the product is colored in a fluorescent color and the catalyst life is shortened. On the other hand, if the reaction hydrogen pressure is increased, these problems can be solved. However, since the pressure of the apparatus is far exceeded, the construction of a new apparatus is required, and the cost is enormous, which is not preferable. Furthermore, a method of performing hydrotreatment in two stages under specific conditions (Japanese Patent Laid-Open No. 5-39492), dividing a gas oil fraction into a plurality of fractions, and subjecting each fraction to desulfurization treatment or desulfurization treatment and decolorization treatment After that, a method of mixing the respective fractions (Japanese Patent Laid-Open No. 4-46993) has been proposed. However, it is not economically sufficient because a new apparatus is required. The reduction of substances was not enough.

As another measure for reducing particulates, a method of collecting and burning by providing a filter in the exhaust pipe has been proposed. However, combustion control and the like are difficult.
It has not been put to practical use. Furthermore, methods of adding oxygen-containing compounds such as alcohols and acetal have been studied (SAE paper 930728, 1993), but these compounds which are currently proposed have low solubility in gas oil fractions, There are problems such as emulsification due to the incorporation of water to lower the combustibility, or the effect of the additive migrating to the aqueous layer being lost, and lowering the cetane number to worsening the combustibility.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems. An object of the present invention is to provide a diesel engine capable of greatly reducing pollutants such as particulates and nitrogen oxides in exhaust gas. An object of the present invention is to provide a pollution fuel composition and a method for producing the fuel economically and efficiently without causing fluorescent coloring.

[0008]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, have found that the sulfur content in the fuel oil for diesel engines is 0.05% by weight or less, and the aromatic ring having three or more rings is used. Sulfur oxides, particulates and nitrogen oxides in exhaust gas can be remarkably reduced by reducing the content of the components to 0.1% or less. The content of the component is 0.1% or less, and the aromatic component having three or more rings is easily partially hydrogenated in the presence of a hydrogenation catalyst, and the combustion exhaust gas contains particulates and nitrogen oxides. The present inventors have found that the number is small and arrived at the present invention.

The present invention comprises only a fraction having a sulfur content of 0.05% by weight or less, an aromatic component having three or more rings of 0.1% or less, and having a boiling point of 150 to 300 ° C. or less. Low pollution fuel oil for diesel engine and 150 ~
The fraction having a boiling point of 300 ° C. is subjected to hydrodesulfurization treatment in the presence of a desulfurization catalyst, or the gas oil fraction is subjected to hydrodesulfurization treatment in the presence of a desulfurization catalyst and then has a boiling point of 150 to 300 ° C. Collect distillate or even 150-300 ° C
And a first gas oil fraction having a sulfur content of 0.04% by weight or less by hydrodesulfurization treatment in the presence of a desulfurization catalyst, and a fraction having a boiling point range of 300 to 380 ° C with hydrogen. A sulfur content of 0.05% by weight or less, which is obtained by mixing with a second gas oil fraction in which the aromatic component having three or more rings is reduced to 0.3% or less by a nuclear hydrogenation treatment in the presence of the added catalyst; In addition, the present invention provides a method for producing a low-pollution fuel oil for a diesel engine, comprising 0.1% or less of an aromatic component having three or more rings.

The low-pollution fuel oil for a diesel engine according to the present invention satisfies the standard for light oil specified in JIS K 2204, but in particular, the standard has a sulfur content of 0.2.
The sulfur content is 0.05% by weight or less, and the aromatic component having three or more rings is 0.1% or less. The aromatic component having three or more rings is
In general, a so-called condensed polycyclic aromatic compound in which three or more, more particularly three or more five- or six-membered rings are condensed, for example, anthracene with or without a substituent such as alkyl,
Phenanthrene, indacene, fluorenefluoranthene, aceanthrylene, acephenanthrylene, pyrene, naphthacene, triphenylene, chrysene and the like are mentioned, but it is practically difficult to accurately specify these components and their amounts. Therefore, in the present invention, the light oil fraction is analyzed by high performance liquid chromatography under the conditions shown in Table 1, and the peak eluted during a retention time of 16 to 27 minutes is represented by a tricyclic or higher aromatic ring. The amount of an aromatic component having three or more rings is calculated from the peak area based on a calibration curve prepared using phenanthrene as an internal standard. For example, when the gas oil fraction is analyzed under the conditions shown in Table 1, the chromatogram shown in FIG. 1 is obtained. The peak between peaks A and B in this figure is defined as an aromatic component having three or more rings. It is.

[Table 1]

It has been found that the above-mentioned aromatic components having three or more rings are hardly contained in the light fraction when cut at 300 ° C. using the distillation equipment of an ordinary petroleum refinery. Therefore, if the sulfur content of this fraction is adjusted to 0.05% by weight or less, the low-pollution fuel oil for diesel engine of the present invention can be obtained. The reduction of the sulfur content can be carried out by commonly used hydrodesulfurization. For example, on an alumina or alumina-silica carrier, Co-Mo, Ni-Mo or Co-N
Using a catalyst loaded with 2 to 20% by weight of metal as a combination of i-Mo, a hydrogen pressure of 10 to 50 kg / cm ² and a temperature of 320 to
380 ° C, liquid hourly space velocity (LHSV) 0.5 to 10 h ^-1 , hydrogen amount 5
Hydrodesulfurization may be appropriately selected from the conditions of 0 to 1500 Nm ³ / kl-oil. That is, 150-300 ° C.
In particular, when the fraction having a boiling point of 180 to 300 ° C. is subjected to hydrodesulfurization treatment in the presence of a desulfurization catalyst as described above and the sulfur content is 0.05% by weight or less, the sulfur content becomes 0.05% by weight. The low-pollution fuel oil for a diesel engine according to the present invention, which contains no more than 0.1% of aromatic components having three or more rings, is obtained.

[0012] Furthermore, the usual 150 to 380
C., particularly a gas oil fraction having a boiling point in the range of 180 to 300 ° C. is subjected to hydrodesulfurization treatment in the presence of a desulfurization catalyst.
The same can be obtained by collecting a fraction having a boiling point of 300 ° C, particularly 180 to 300 ° C. In this case, the hydrodesulfurization treatment does not require the sulfur content to be 0.05% by weight or less, and varies depending on the type of oil. 300 ° C, especially 18
The fraction having a boiling point in the range of 0 to 300 ° C. can be 0.05% by weight or less. However, the low-pollution fuel oil for diesel engines obtained by this method tends to have low fuel efficiency because it is light.

As another method for producing the low-pollution fuel oil for a diesel engine of the present invention, the light portion of the light oil fraction is excessively hydrodesulfurized and the heavy portion is subjected to nuclear hydrogenation treatment. This is a method in which aromatic components having a ring or more are reduced, and both are mixed. As the light portion, if the cut temperature in the distillation apparatus is set at 300 ° C. and the light fraction is used, hydrodesulfurization is easy, and the aromatic components having three or more rings after mixing can be easily reduced to 0.1%. It can be: This light portion is hydrodesulfurized at a high temperature of 350 ° C or higher,
It tends to be colored by fluorescent substances. However, this light component is susceptible to hydrodesulfurization, and a highly desulfurized oil can be obtained even under less severe conditions. The hydrodesulfurization in this case is desulfurization using the above-described catalyst under the above-mentioned conditions so that the sulfur content is selected to be 0.04% by weight or less. This is preferable because the desulfurized oil is not colored in a fluorescent color. On the other hand, as the heavy portion, the remaining portion obtained by removing the light fraction from the entire distillate of light oil, that is, the cut temperature in the distillation apparatus is set to 300 ° C., and the heavy fraction is used.
Other heavy gas oil base materials having a boiling point range of 00 to 380 ° C may be used. This part contains a large amount of aromatic components having three or more rings, and is subjected to hydrogenation treatment and nucleus hydrogenation to reduce the aromatic components having three or more rings to 0.3% or less. This hydrogenation treatment is carried out, for example, by using a catalyst in which 2 to 20% by weight of Ni or Ni-Mo or a combination of Ni-Co-Mo is supported as a metal on an alumina or alumina-silica carrier, and a hydrogen pressure of 10 to 20%.
150 kg / cm ² , temperature 320-400 ° C, liquid space velocity (L
HSV) 0.5 to 10 h ^-1 , hydrogen amount 50 to 1500 Nm ³ / kl-oi
It can be appropriately selected from the conditions of l. The hydrodesulfurized oil of the light fraction and the hydrotreated oil of the heavy fraction may be mixed as they are at the ratio before cutting, but the heavy fraction is used with respect to 1 part by weight of the hydrodesulfurized oil of the light fraction. There is no particular problem even if the fraction is mixed with a hydrotreated oil in a ratio of 0.3 to 2 parts by weight. Less than 0.3 parts by weight of the hydrogenated treated oil in the heavy fraction is not economical because the amount of the heavy oil to be treated increases and the fuel efficiency of the diesel engine fuel oil is reduced, which is less preferable. Absent.
On the other hand, when the amount of the hydrotreated oil of the heavy fraction is 2 parts by weight or more, the amount of the hydrotreated oil having a relatively high treatment cost is large, which is not economically preferable.

[0014]

Industrial Applicability The low-pollution fuel composition for a diesel engine of the present invention can greatly reduce pollutants such as sulfur oxides, nitrogen oxides, hydrocarbons and particulates in exhaust gas. Thus, this fuel can be produced economically and efficiently without causing fluorescent coloring.

[0015]

EXAMPLES Example of Analysis A gas oil fraction having the properties shown in Table 2 was cut at a temperature shown in Table 3 using a distillation apparatus having a theoretical plate number of 15 and a reflux ratio of 4, and the specific gravity and sulfur content of each fraction were determined. And analysis of aromatic components. The results are shown in Table 3. The aromatic component was subjected to high performance liquid chromatography under the conditions shown in Table 1 above, and a representative chromatogram is shown in FIG. In the figure, some of the aromatic components peak at a retention time of C to D of 4 to 9 minutes, and the bicyclic aromatic components have a retention time of 9 to 9 minutes.
The peak of D to A for 16 minutes and the aromatic component of the tricyclic ring can be identified by the peak between A and B for 16 to 27 minutes of retention time. From the respective peak areas, calibration using a standard sample prepared in advance is performed. Using the line, the amount of the aromatic component in each ring was determined.

[Table 2]

[Table 3]

From these results, it was found that IBP-300 in the gas oil fraction
It can be seen that the fraction up to ° C. contains 0.1% of tricyclic or higher aromatic components.

Example 1 Among the fractions distilled above, the fraction up to IBP to 300 ° C. was used on a catalyst in which 3% by weight of cobalt as a metal and 10% by weight of molybdenum as a metal were supported on an alumina carrier. Hydrogen pressure 30 kg / cm ² , temperature 300 ° C, liquid space velocity 3
Hydrodesulfurization was performed under the conditions of h ^-1 and a hydrogen amount of 100 Nm ³ / kl-oil, and a fraction lighter than 180 ° C. was cut to obtain a hydrodesulfurized oil having the properties shown in Table 4. To this hydrodesulfurized oil was added alkylanthracene, which is a tricyclic aromatic component (dissolved in 4 parts by weight of methylnaphthalene), so that the tricyclic aromatic component was 0.5%, 1. A test oil prepared to be 2% was prepared.

[Table 4]

The above hydrodesulfurized oil, a light oil fraction having the properties shown in Table 2 and a test oil were burned by a direct injection diesel engine shown in Table 5, and the indicated average effective pressure was 6 kg / cm ^2.
In exhaust gas under the following conditions
(PM) (Mini Dilution System (manufactured by Horiba)
COLLECTION), soluble component (SOF) (difference between the filter PM is attached, the remaining amount which was extracted 6 hours with dichloromethane) and NO _x (automotive exhaust gas measurement apparatus MEXA
-8120D, manufactured by Horiba, Ltd.). The results are shown in Table 6.

From these results, when the sulfur content is 0.05% by weight or less and the aromatic component having three or more rings is 0.1% or less, particulates, hydrocarbons, SO _x , SO _x ,
It can be seen that air pollutants such as NO _x can be significantly reduced.

[Table 5]

[Table 6]

Example 2 Among the fractions distilled in the analysis example, the fraction up to IBP-300 ° C. was used on a alumina carrier using a catalyst having 3% by weight of cobalt as a metal and 10% by weight of molybdenum as a metal. Hydrogen desulfurization under the conditions of hydrogen pressure of 30 kg / cm ² , temperature of 300 ° C., liquid hourly space velocity of 3.0 h ⁻¹ , and hydrogen amount of 100 Nm ³ / kl-oil, cut off a fraction lighter than 180 ° C. A hydrodesulfurized oil was obtained. In addition, of the fractions distilled in the analysis example, 30
Hydrogen pressure 70 kg / cm ² , temperature 34, using a catalyst in which a fraction from 0 to EP is supported on an alumina carrier by 3% by weight of nickel as metal and 12% by weight of molybdenum as metal.
0 ° C, liquid hourly space velocity 0.7h ^-1 , hydrogen amount 500Nm ³ / kl-oil
Under the conditions described above, hydrogenation treatment was performed, and a fraction lighter than 180 ° C. was cut to obtain a hydrogenated oil.

A fuel oil for a diesel engine having the properties shown in Table 7 was prepared by mixing 1 part by weight of the hydrodesulfurized oil with 1 part by weight of the hydrogenated oil. This was burned using the engine shown in Example 1, and the air pollutants in the exhaust gas were similarly analyzed. The results are shown in Table 8.

[Table 7]

[Table 8]

The results show that the diesel engine fuel oil of the present invention can significantly reduce the particulate matter and nitrogen oxides in the exhaust gas. Further, this type of fuel can be produced at a low hydrogen pressure and without fluorescent coloring. It can be seen that it can be manufactured economically and efficiently.

[0023]

[Brief description of the drawings]

FIG. 1 is a chromatogram obtained by analyzing a gas oil fraction by high performance liquid chromatography.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-46993 (JP, A) JP-A-5-311179 (JP, A) JP-A-8-509999 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) C10G 45/08 C10G 65/08 C10L 1/08

Claims (3)

(57) [Claims] 1. A sulfur content of 0.05 wt% or less, and tricyclic or more aromatic components Ri Do from 0.1% or less, 150
300 ° C. or lower pollution fuel oil for diesel engines Do that because only a fraction in the boiling range. 2. A fraction having a boiling point of 150 to 300 ° C. or lower is subjected to hydrodesulfurization treatment in the presence of a desulfurization catalyst, or a gas oil fraction is subjected to hydrodesulfurization treatment in the presence of a desulfurization catalyst. in sulfur content, and collecting a fraction in the boiling range of to 300 ° C. is 0.05 wt% or less, and Ri Do from tricyclic or more aromatics is not more than 0.1%, 150
Method for producing a low-pollution fuel oil for diesel engines Do that because only a fraction in the boiling range of to 300 ° C. or less. 3. A fraction having a boiling point of 150 to 300 ° C. is hydrodesulfurized in the presence of a desulfurization catalyst to reduce the sulfur content to 0.1.
The first gas oil fraction of not more than 04% by weight and 300 to 380 ° C
Characterized by mixing a second gas oil fraction where the fraction in the boiling range in the presence of a hydrogenation catalyst nuclei hydrotreating to tricyclic or more aromatics is 0.3% or less The sulfur content is 0.
Not more than 0.5% by weight and an aromatic component having three or more rings is 0.1
% Of low-pollution fuel oil for diesel engines.