JP2000265180A - Light oil with reduced foamability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject light oil with extremely low sulfur content. SOLUTION: This light oil with reduced foamability is such one as to be <=0.005 wt.% in sulfur content, <=24 vol.% in aromatic fraction content, and 4.0-5.2 mm2/s in dynamic viscosity at 30 deg.C; wherein it is preferable that this light oil has a 50 vol.% distillation temperature of 282-300 deg.C and a density at 15 deg.C of 0.83-0.86 g/cm3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to light oil used as a fuel for a diesel engine, and more particularly to a fuel tank for a vehicle (hereinafter referred to as a "diesel vehicle") such as a passenger car or a truck equipped with a diesel engine. The present invention relates to light oil that secures safety at the time of refueling by suppressing the height of foam (hereinafter referred to as foaming property) generated when refueling.

[0002]

2. Description of the Related Art Due to recent environmental problems, the sulfur content in diesel oil is reduced from 0.05% by mass or less to 0.0% in order to reduce NOx and particulates in exhaust gas from diesel vehicles.
Light oil reduced to about 05% by mass or less (hereinafter referred to as ultra-low sulfur light oil) is being studied.

As a desulfurization method for obtaining an ultra-low sulfur gas oil, a hydrodesulfurization method under a high temperature and a high pressure is generally used, and accompanying the desulfurization, an aromatic component, particularly a polycyclic aromatic component, is subjected to nuclear hydrogenation. As a result, the aromatic content is reduced at the same time as the sulfur content.

On the other hand, when refueling diesel vehicles with diesel oil, in Japan, a full stop device is attached to a refueling nozzle of a weighing machine at a refueling office, and when the diesel oil is almost full, a foam surface is detected. Safety measures are taken to prevent the oil pump from automatically stopping and light oil from overflowing.

[0005]

When the foaming properties of ultra-low sulfur gas oil were examined, it was found that the foaming properties tended to increase as the aromatic content decreased. Since ultra-low sulfur gas oil has a higher foaming property than conventional gas oil, even if the full stop device operates normally and refueling stops, bubbles may overflow from the oil filler port of diesel vehicles, which is a safety problem. Is worried.

On April 1, 1998, the self-service refueling service was lifted and the opportunity for customers to grip the refueling nozzles increased in the future. Required.

As a means for suppressing foaming properties, it is conceivable to add a known antifoaming agent such as a copolymer of dimethylsiloxane and oxyethylene to light oil. Since the cost increases, it is desired to suppress the foaming property by other means.

[0008] The present invention has been made to solve such problems and provides an ultra-low sulfur gas oil having a low foaming property even when an antifoaming agent is not used.

[0009]

Means for Solving the Problems The inventors of the present invention, based on the idea that foaming properties can be suppressed by optimizing the physical properties, have established a correlation between various physical properties of ultra-low sulfur gas oil and foaming properties. investigated.

[0010] As a result, of the distillation properties, 50% by volume of the distillation temperature (hereinafter referred to as distillation (50%)) to the end point beyond the distillation point, flash point, 10% residual carbon content of residual oil, cetane index Did not have any relationship with foaming properties.

On the other hand, the kinematic viscosity at 30 ° C. (hereinafter referred to as kinematic viscosity (30 ° C.)), the fore-run portion from the initial boiling point to the distillation (50%) of the distillation properties and the density at 15 ° C. (Hereinafter referred to as density (15 ° C.).) It has been found that there is a correlation with foaming properties, and intensive research was conducted with the idea that foaming properties could be suppressed by optimizing these physical properties.

As an experimental fact, the kinematic viscosity (30 ° C.) of the above three physical properties most affected foaming properties. (30 ° C) ”,“ Kinematic viscosity (30 ° C)
And kinematic viscosity (30 ° C.) and density (15 ° C.) ”or“ kinematic viscosity (30%)
C), distillation (50%) and density (15 C)
It has been found that if any one of the four methods is adopted, light oil having less foaming property can be obtained.

That is, the light oil according to the present invention has a sulfur content of 0.005% by mass or less, an aromatic content of 24% by volume or less, and a kinematic viscosity (30 ° C.) of 4.0 mm ² / s to 5.2 mm ^2.
/ S or less, distillation (50%) is 282 ° C. or more and 300 ° C. or less, and density (15 ° C.) is 0.83 g / cm ^3.
More preferably, it is 0.86 g / cm ³ or less.

It is preferable that the dewaxed desulfurized gas oil base material contains less than 50% by volume based on the total amount of the gas oil. Usually, the desulfurized gas oil has difficulty in controlling the kinematic viscosity (30 ° C.), the distillation (50%) and the density (15 ° C.) within the above ranges due to the restriction of low-temperature fluidity such as cloud point. Since the dewaxed desulfurized gas oil has good low-temperature fluidity, it is easy to suppress the foaming of the light oil while ensuring low-temperature fluidity by blending it.

The low-temperature fluidity improver such as ethylene-vinyl acetate copolymer and the lubricity improver such as fatty acid and fatty acid ester have no causal relationship with the foaming property. Therefore, the present invention depends on the presence or absence of these additives. The potency is not affected.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The light oil according to the present invention has a sulfur content of 0.005% by mass or less, an aromatic content of 24% by volume or less, and a kinematic viscosity (30 ° C.) of 4.0 mm ² / s to 5.2 mm. ^Two
/ S or less, distillation (50%) is 282 ° C. or more and 300 ° C. or less, and density (15 ° C.) is 0.83 g / cm ^3.
More preferably, it is 0.86 g / cm ³ or less.

Here, the sulfur content is determined according to JIS K2541.
Reference 2 (crude oil and petroleum products-sulfur content test method-wavelength dispersive X-ray fluorescence method) (corresponding to ISO / CD14596) can be determined by the radiation type wavelength dispersive X-ray fluorescence method.
The currently widely used radiation excitation method is not appropriate as a method for measuring sulfur content because of its accuracy problem in the ultra-low sulfur region.

The aromatic component is a total value of one to four ring aromatic components, and can be determined by JPI-5S-49-97 (petroleum products-hydrocarbon type test method-high performance liquid chromatography).

The kinematic viscosity (30 ° C.) is determined according to JIS K 228
3 (crude oil and petroleum products-kinematic viscosity test method and viscosity index calculation method). The kinematic viscosity (30 ° C.) of the light oil according to the present invention is 4.0 mm ² / s.
Not less than 5.2 mm ² / s, preferably 4.1 mm ² / s
More than 5.0mm ² / s or less, more preferably 4.1mm ²
/ S or more and 4.8 mm ² / s or less. Kinematic viscosity (30
C.) is less than 4.0 mm ² / s, the suppression of foaming is clearly inferior. When the kinematic viscosity (30 ° C.) exceeds 5.2 mm ² / s, the foaming property is suppressed and the safety at the time of refueling is high, but the time until the generated foam disappears (hereinafter referred to as defoaming time). It is not preferable because it becomes longer and the refueling time is extended.

Distillation (50%) is performed according to JIS K 2254
(Petroleum product-Distillation test method) can be determined by the atmospheric distillation test method. Distillation of gas oil according to the invention (50%)
Is from 282 ° C to 300 ° C, preferably from 284 ° C to 296 ° C, more preferably from 286 ° C to 292 ° C.
It is as follows. If the distillation (50%) is below 282 ° C,
Foamability increases. When the distillation (50%) exceeds 300 ° C., although the foaming property is excellently suppressed, the defoaming time is inferior and the oil supply time is too long, which is not preferable.

The density (15 ° C.) is determined according to JIS K 2249.
(Crude oil and petroleum products-density test method and density / mass / volume conversion table). The density (15 ° C.) of the light oil according to the present invention is 0.83 g / cm ³ or more and 0.86 g.
/ Cm ³ or less, preferably 0.835 g / cm ³ or more.
855 g / cm ³ or less, more preferably 0.84 g / c
m ³ or more and 0.85 g / cm ³ or less. Density (15 ° C)
Is less than 0.83 g / cm ^{3, the} foamability increases. If the density (15 ° C.) exceeds 0.86 g / cm ³ , the foaming properties are low, but the defoaming time is long and the oiling time is long, which is not preferable.

The gas oil of the present invention does not contain a dewaxed desulfurized gas oil base material as an essential component, but uses a dewaxed desulfurized gas oil base material to make the gas oil less than 50% by volume, especially 20 to 50% by volume based on the total amount of the gas oil.
If it is less than the above, it can be easily produced. However, when the dewaxed and desulfurized gas oil base is 50% by volume or more, the kinematic viscosity (30 ° C.), distillation (50%), and density (15 ° C.) become excessive, although the foaming suppression effect is improved. Problems with foam time can occur and are undesirable.

The dewaxed and desulfurized gas oil base material used in the present invention can be obtained from a straight-run gas oil obtained from an atmospheric distillation unit for crude oil, a vacuum gas oil obtained from a vacuum distillation unit, and also from an atmospheric distillation unit for crude oil. Kerosene straight run, catalytic cracking gas oil obtained from catalytic cracking unit, gas oil removed from heavy oil indirect desulfurizing unit,
It is a light oil base material produced by combining a hydrodesulfurization step and a dewaxing step, using, as a raw material oil, a mixture of direct desulfurized gas oil obtained from a heavy oil direct desulfurization unit.

A typical characteristic of the dewaxed desulfurized gas oil base material is that the density (15 ° C.) is 0.84 g / cm ³ or more, especially 0.84 g / cm ^3.
0.87 g / cm ³ , kinematic viscosity (30 ° C.) 4.0 mm ²
/ S or more, particularly 4.5 to 6.0 mm ² / s, the sulfur content is 0.008% by mass or less, and the temperature range from the initial boiling point to the end point (hereinafter referred to as the distilling temperature range) is 150 to 400. It is about ° C.

The sulfur content of the dewaxed desulfurized gas oil base material is 0.008.
% By mass or less, the sulfur content of the target light oil is reduced to 0.00 by blending with a desulfurized kerosene base material or another desulfurized light oil base material.
It can be adjusted to 5% by mass or less.

The hydrodesulfurization step for obtaining the dewaxed desulfurized gas oil base material used in the present invention is not particularly limited in terms of the process, operating conditions, etc., and may be appropriately combined with any known gas oil desulfurization apparatus. Can be used.

In the dewaxing step for obtaining the dewaxed desulfurized gas oil base material used in the present invention, the process, operating conditions and the like are not particularly limited, and any known apparatus can be adopted. The dewaxing step uses a special catalyst such as Pt-H-mordenite or synthetic zeolite to selectively hydrocrack normal paraffins and paraffins with few side chains in the feedstock, and has excellent low-temperature fluidity. This is a step for obtaining a gas oil base material. For example, in addition to the BP contact dewaxing method and the MDDW method described in “New Petroleum Refining Process” edited by the Japan Petroleum Institute, FTZ
And the CFI method are known. As another dewaxing step, a method such as solvent dewaxing can be used.

Other base materials for the gas oil of the present invention include desulfurized kerosene, desulfurized gas oil, direct desulfurized gas oil obtained from heavy oil direct desulfurization unit, de-oiled gas oil obtained from heavy oil indirect desulfurization unit, and contact obtained from catalytic cracking unit. Cracked gas oil, hydrocracked kerosene, hydrocracked gas oil and the like can also be used within a range in which the desired gas oil can be produced.

Furthermore, known fuel oil additives can be used alone or in combination in the light oil of the present invention. As these additives, for example, ethylene vinyl acetate copolymer, ethylene (meth) acrylate copolymer,
Low-temperature fluidity improvers such as chlorinated polyethylene, poly (meth) alkyl acrylate and alkenyl succinamide; lubricity improvers such as amine compounds, ester compounds, fatty acid compounds and fatty acid amides;
Cetane number improvers such as organic peroxides, detergents and dispersants such as alkenyl succinimides and polyalkylamines, antioxidants such as phenols and amines, metal deactivators such as salicylidene derivatives, and azo dyes There are coloring agents and the like. In addition, an antifoaming agent such as polydimethylsiloxane, a copolymer of dimethylsiloxane and trifluoropropylmethylsiloxane, and a copolymer of dimethylsiloxane and oxyethylene may be blended, but this is not necessary.

The amounts of these additives are optional.
The amount of each additive is 0.5% by mass or less, preferably 0.2% by mass or less, based on the total amount of light oil.

The light oil according to the present invention is not particularly limited in properties other than those described above. However, as a fuel oil for an internal combustion engine, the distilling temperature range is 145 to 400 ° C., preferably 160 to 370 ° C. The scale WS1.4 is 4
It is desirable that the cetane number is 60 μm or less, preferably 400 μm or less, and the cetane number is 45 or more, preferably 50 or more.

[0032]

The present invention will be described below in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples.

In the following Examples and Comparative Examples, the density (15 ° C.), initial boiling point, distillation (50%), end point, kinematic viscosity (30 ° C.), sulfur content, cloud point, plugging point, pour point, Cetane index, aromatic content, WS1.4 and foamability were determined by the following methods.

The density (15 ° C.) is based on JIS K 2249, and the initial boiling point, distillation (50%) and end point are JIS K 2249.
According to the atmospheric pressure distillation test method of No. 2254, the kinematic viscosity (30
° C) is determined by the kinematic viscosity test method of JIS K 2283,
The sulfur content is determined by the radiation type wavelength dispersion type fluorescent X-ray method of JIS K2541 Reference 2, and the cloud point is determined by JIS K2269.
According to the cloud point test method (pour point of crude oil and petroleum products and cloud point test method of petroleum products), the clogging point is JIS
According to K 2288 (light oil-clogging point test method), the pour point is determined according to the pour point test method of JIS K 2269.
The cetane index is determined by a method of calculating a cetane index using a four-variable equation of JIS K 2280 (petroleum product-fuel oil-octane number and cetane number test method and cetane index calculation method). By
WS1.4 was determined by JPI-5S-50-98 (light oil-lubricity test method).

The foaming property was measured by VS Technology (VS TEC).
HNOLOGIES SA (19 RUE DES FRERES LUMIERE 69680 CH
ASSIEU FRANCE)) foam tester (TEST BNP DE MOU
SSAGE (P / N VSTM000608B)).

In the foaming tester, the light oil to be tested is previously sucked into the glass tube of the tester, and then 100 mL of the light oil is injected with nitrogen gas at a pressure of 400 mbar (0.04 MPa) for 20 minutes.
Spout into a 0 mL graduated cylinder. At this time, the foaming property is
The height of the foam that is created immediately after the end of ejection
Expressed by L. The foaming property is a numerical value of 100 mL or more, and light oil having a smaller value indicates less foaming property.

Tables 1 and 2 show the properties and evaluation results (foamability) of the light oils of the examples and comparative examples. Example 3
Table 3 shows properties of the desulfurized kerosene base material, the dewaxed desulfurized gas oil base material, and the desulfurized gas oil used as the base oil of the dewaxed desulfurized gas oil base material used in Table 4.
Shown in

[0038]

[Table 1]

[0039]

[Table 2]

[0040]

[Table 3]

The gas oils of Examples 1 and 2 in Table 1 are obtained from a middle-distillate crude oil at a normal pressure distillation unit having a sulfur content of 1.3% by mass and a catalytic cracking unit for the straight-run gas oil. Using a crude oil having a sulfur content of 1.2% by mass mixed with cracked gas oil, the hydrogen partial pressure of the reaction tower was 50 kgf / cm ² (about 4.9).
× 10 ⁶ Pa), reaction temperature: 330 ° C., LHSV: 0.
Hydrodesulfurized using an alumina carrier / Co-Mo sulfide catalyst under the conditions of 9 hr- ¹ and a hydrogen / oil ratio of 250 L / L. The gas oil of Example 3 is obtained by mixing 45 parts of the desulfurized gas oil base material shown in Table 3 with 55 parts of the desulfurized gas oil of Comparative Example 3 (hereinafter referred to as desulfurized gas oil A). The gas oil of Example 4 was obtained by blending 60 parts of the desulfurized gas oil of Comparative Example 4 (hereinafter referred to as desulfurized gas oil B) with 5 parts of the desulfurized kerosene base material shown in Table 3 and 35 parts of the dewaxed desulfurized gas oil base material.

Each of them is a low-temperature fluidity improver of ethylene vinyl acetate copolymer system (PA manufactured by Infinium Japan Co., Ltd.)
RAFLOW240) and a fatty acid ester-based lubricity improver (PARADYNE manufactured by Infinium Japan KK)
655) was added as appropriate.

The light oils of Comparative Examples 1 to 4 in Table 2 were obtained by using a sulfur content of 1.1 to 1 obtained from an atmospheric distillation apparatus for Middle Eastern crude oil, respectively.
Using 1.4 straight-run gas oil as feed oil, hydrogen partial pressure of the reaction tower: 5
0 kgf / cm ² (about 4.9 × 10 ⁶ Pa), reaction temperature:
330 ° C., LHSV: 0.9 hr ¹¹ , hydrogen / oil ratio: 25
It was hydrodesulfurized under the conditions of 0 L / L using an alumina carrier / Co-Mo sulfide catalyst.

In Comparative Examples 1 and 2, 150 mg / L of the above-mentioned lubricity improver was added.

From the comparison between the example according to the present invention and the comparative example,
It can be seen that the foaming property of the gas oil, which is optimized for the density (15 ° C.), distillation (50%), and kinematic viscosity (30 ° C.) of the ultra-low sulfur gas oil, is suppressed as compared with the untreated gas oil.

It is also apparent that if less than 50% by volume of the unwaxed and desulfurized gas oil base material is blended with the untreated gas oil, it can be easily modified into a gas oil having excellent foaming properties and ensuring safety during refueling. The dewaxed desulfurized gas oil base material shown in Table 3 was prepared by using a straight-run gas oil having a sulfur content of 1.3% by mass obtained from a normal-pressure distillation apparatus for Middle Eastern crude oil and converting the hydrogen partial pressure of the reaction tower to 50 kgf / cm ² (about 4 kg / cm ² ). .9
× 10 ⁶ Pa), reaction temperature: 330 ° C., LHSV: 0.
Under the conditions of 9 hours to ¹ and a hydrogen / oil ratio of 250 L / L, a desulfurized light oil obtained by hydrodesulfurization using an alumina carrier / Co-Mo sulfide catalyst was used as a feed oil, and the hydrogen partial pressure of the reaction column was 30.
kgf / cm ² (about 2.9 × 10 ⁶ Pa), reaction temperature: 3
The catalyst was dewaxed under the conditions of 50 ° C. and LHSV: 1.5 hr to ¹ using a synthetic zeolite catalyst.

[0047]

According to the present invention, without adding an antifoaming agent,
By means of optimizing the physical properties of ultra-low sulfur gas oil, gas oil with low foaming properties can be obtained.

The light oil according to the present invention is a light oil whose safety at the time of refueling is ensured by suppressing the height of bubbles generated when refueling a diesel vehicle. % Can be produced.

Claims (4)

[Claims] 1. A sulfur content of 0.005 mass% or less, an aromatic content of 24 volume% or less, and a kinematic viscosity at 30 ° C. of 4.
A light oil having reduced foamability, characterized in that the oil is not less than 0 mm ² / s and not more than 5.2 mm ² / s. 2. Distillation temperature of 50% by volume is 282 ° C. or more and 30% or more.
The light oil having reduced foamability according to claim 1, wherein the temperature is 0 ° C or lower. 3. The density at 15 ° C. is 0.83 g / cm.
^{3. The} light oil having reduced foamability according to claim 1 or 2, wherein the light oil has a weight of ³ or more and 0.86 g / cm ³ or less. 4. A dewaxed and desulfurized gas oil base material having a total amount of 5
The light oil having reduced foamability according to claim 1, 2 or 3, which contains less than 0% by volume.