JP2011137115A - Gasoline fuel composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gasoline fuel composition which is hard to become cloudy as compared with conventional gasoline. <P>SOLUTION: In the gasoline fuel composition, the content of aromatic hydrocarbon is 40% by volume or less, the content of saturated hydrocarbon is 40% by volume or more, the relative dielectric constant is 2.10 or less, and the research octane number is 96 or more. A temperature dependency coefficient K of saturated water content, represented by: K=3.5×O+7.3×t+3.3×C9 äO: olefin content (% by volume), t: toluene content (% by volume), C9: 9C aromatic hydrocarbon (% by volume)}, is preferably 250 or less. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a gasoline fuel composition constituting gasoline fuel used in a gasoline engine mounted on an automobile or the like.

  A highly volatile gasoline fuel composition (hereinafter sometimes referred to as “gasoline”) is generally stored in a floating roof tank from the time it is manufactured until it is shipped. In this floating roof type tank, the floating roof follows the change in the liquid level accompanying the change in the storage amount, and the hydrocarbon gas can be prevented from staying in the gap between the roof and the liquid level. However, since there is a gap between the floating roof and the tank wall surface, there is a problem that rainwater flows in from there. This gap is usually sealed with an elastic material, and the inflow of rainwater from the gap is suppressed to some extent, but it is difficult to completely prevent it, and rainwater mixed in gasoline is regularly However, the amount of water dissolved as saturated water cannot be removed. Therefore, gasoline supplied to general consumers has a trace amount equivalent to the amount of saturated water. Contains moisture.

  On the other hand, gasoline has a feature that the amount of saturated water easily changes depending on temperature. For this reason, when the temperature of gasoline containing water drops sharply due to a drop in outside air, the precipitation of water may cause white turbidity, which may affect product quality. Such white turbidity is also called water turbidity, and a countermeasure has been devised. For example, JP 2009-227694 A discloses a gasoline excellent in water turbidity prevention performance.

  In this document, attention is paid to the fact that the saturated water content in gasoline and its temperature dependence are determined by the ratio of hydrocarbon compounds constituting gasoline, and the ratio of aromatics and unsaturated hydrocarbons having a predetermined number of carbon atoms is determined in advance. By using the base material which becomes the structure of the above, improvement of water turbidity prevention performance is aimed at.

JP 2009-227694 A

  However, in this document, the easiness of water turbidity (white turbidity) is defined by the white turbidity temperature in a 100 ppm water content sample. In reality, however, the water content of stored gasoline is always near the saturated water content. Therefore, the easiness of cloudiness is most affected by the temperature dependence of the saturated water content when the gasoline temperature is lowered. That is, the definition of easiness of cloudiness in the above document does not accurately represent the actual cloudiness phenomenon, and the gasoline disclosed in the above document becomes cloudy when the outside temperature actually decreases rapidly. There was a fear. Except for the above-mentioned documents, there is not much research on the ease of cloudiness of gasoline, and gasoline that does not easily cloudy has not been proposed so far.

  Therefore, an object of the present invention is to provide a gasoline fuel composition that is less turbid than conventional gasoline.

  The gasoline fuel composition according to the present invention has an aromatic hydrocarbon content of 40% by volume or less, a saturated hydrocarbon content of 40% by volume or more, a relative dielectric constant of 2.10 or less, and a research octane number (RON). ) Is 96 or more. The content of aromatic hydrocarbon is preferably 35% by volume or less, and more preferably 30% by volume or less. The saturated hydrocarbon content is preferably 48% by volume or more, and more preferably 55% by volume or more. The relative dielectric constant is preferably 2.07 or less, and more preferably 2.04 or less.

In the gasoline fuel composition according to the present invention, the saturated moisture temperature dependency coefficient K represented by the following formula is preferably 250 or less.
Saturated water temperature dependency coefficient K = 3.5 × O + 7.3 × t + 3.3 × C9
O: Olefin content (volume%)
t: Toluene content (volume%)
C9: C9 aromatic hydrocarbon (volume%)
The saturated moisture temperature dependency coefficient K is more preferably 210 or less, and most preferably 180 or less.

  As the base material of the gasoline composition according to the present invention, isomerized gasoline, cracked gasoline, and alkylate are preferable. In particular, the alkylate is composed only of saturated hydrocarbons, and since it has a relatively high RON among hydrocarbon base materials, it is particularly suitable as a gasoline base material in which white turbidity hardly occurs. However, since the RON required for the present invention cannot be satisfied if the mixing ratio becomes too high, the alkylate mixing ratio is preferably 10 to 40% by volume, more preferably 20 to 35% by volume, and more preferably 25 to 32%. Volume% is most preferred. “Isomerized gasoline” is a base material obtained by isomerizing a desulfurized light naphtha obtained by desulfurizing naphtha obtained from an atmospheric distillation apparatus of crude oil and then fractionating it into a fraction having a low boiling point by distillation. It is. “Decomposed gasoline” is a base material obtained by catalytic cracking or pyrolysis of heavy oil. Each base material obtained by distilling this cracked gasoline into a fraction having a low boiling point and a fraction having a high boiling point by distillation is “light cracked gasoline” and “heavy cracked gasoline”. Furthermore, the “alkylate” is a base material obtained by adding (alkylating) a lower olefin by-produced from a catalytic cracking apparatus to a hydrocarbon such as isobutane.

  Further, in addition to the above-mentioned base material, contact reformed gasoline having 9 or more carbon atoms may be appropriately mixed. “Catalytic reformed gasoline” is a base material obtained by reforming the remaining heavy fraction obtained by distillation of the desulfurized light naphtha by distillation, for example, by a catalytic reforming method such as a platforming method. And this base material is obtained by fractionating this catalytically reformed gasoline into a fraction containing an aromatic component having 9 or more carbon atoms.

  Since the catalytically reformed gasoline having 7 carbon atoms obtained by fractionating the above catalytically modified gasoline into a fraction containing an aromatic content having 7 carbon atoms has a high octane number, It is preferably used. However, it is preferable that the base material of the gasoline fuel composition according to the present invention is not more than 20% by volume, more preferably not more than 10% by volume, and more preferably not more than 5% by volume because of the property of easily taking in moisture. Is most preferable.

Moreover, what is shown below is mentioned as another gasoline base material which can be used as a base material of the gasoline fuel composition of this invention.
"Butane / Butylene fraction"
It is a base material obtained by refining petroleum gas by-produced from an atmospheric distillation apparatus, a naphtha desulfurization apparatus, a catalytic reforming apparatus, a catalytic cracking apparatus or the like.
"Oxygen compounds of alcohol or ethers"
Specific examples of the alcohols include methanol, ethanol, propanol and the like, and examples of the ethers include methyl-tertiary-butyl ether (MTBE) and ethyl-tertiary-butyl ether (ETBE).

  According to the present invention, it is possible to obtain a gasoline fuel composition that is small in temperature dependence and hardly causes water precipitation and is less likely to become cloudy.

  The temperature dependence of the saturated water content that greatly affects the ease of clouding is the change of the saturated water content with respect to the temperature change, for example, the slope of the approximate line when plotting the saturated water content at each temperature . The present inventors have found substances and physical properties that particularly affect the temperature dependence of the saturated water content of gasoline, where it is considered that as the inclination is smaller, the cloudiness is less likely to occur. More specifically, it has been found that the temperature dependence of the saturated water content is affected by the contents of aromatic hydrocarbons and saturated hydrocarbons and the relative dielectric constant. In addition, among aromatics, particularly those of toluene, aromatic hydrocarbons having 9 carbon atoms, and moreover, they are easily affected by olefins, and they are easily affected by the temperature dependence coefficient K of the saturated moisture content composed of them. I found. The present invention is based on the new knowledge.

It is a figure which shows a cloudy state.

The following base materials were blended to obtain gasoline that is less cloudy than conventional gasoline. In addition, as a comparative example, the same base material was mixed and the same gasoline was prepared.
Base material 1: Isomerized gasoline base material 2: Light cracked gasoline base material 3: Heavy cracked gasoline base material 4: Alkylate base material 5: Contact reformed gasoline base material with 9 or more carbon atoms 6: Contact with 7 carbon atoms Reformed gasoline

  The properties of the base material are shown in Table 1, and the properties of the obtained gasoline and the cloudiness temperature are shown in Table 2. In addition, the measuring method of each property and cloudiness temperature is as showing below.

<Density>
Measured according to JIS K 2249 “Crude oil and petroleum products—density test method and density / mass / volume conversion table”.
<Vapor pressure>
Measured according to JIS K 2258 “Crude oil and fuel oil—Vapor pressure test method—Lead method”.
<Distillation properties>
Measured according to JIS K 2254 "Petroleum products-Distillation test method".
<Octane number>
It was measured by the research method octane number test method of JIS K 2280 “Petroleum products—fuel oil—octane number and cetane number test method and cetane index calculation method”.
<GC composition analysis>
Measured according to JIS K 2536-2 “Petroleum products—component test method Part 2: Determination of all components by gas chromatograph”.
<Saturated water content>
After leaving water (distilled water), a sample, and a 100 ml glass container with a lid at room temperature, put 10 ml of water and 90 ml of the sample into the glass container, shake the glass container vigorously for 1 minute, and dissolve the water sufficiently. It was. And the said glass container was set to the stand in the thermostat set to 30 degreeC, and it left still overnight, and stabilized the sample. Next, the thermostat is set at the saturated moisture measurement temperature and allowed to stabilize for 1 hour. Then, the sample temperature is confirmed, the supernatant is directly collected from the glass container with a syringe, and the moisture is measured by the Karl Fischer method (JIS K 2275). The average value measured twice with the saturated water content at that temperature. In addition, the saturated water | moisture-content measurement temperature was made into 4 types, 25 degreeC, 10 degreeC, 5 degreeC, and 0 degreeC, and measured similarly about each temperature.
<Relative permittivity>
Using an LCR meter 4284A (product name, manufactured by Agilemt), the sample capacitance C and the sample capacitance Co at 25 ° C. were measured, and the relative dielectric constant εr was calculated by the following equation.
εr ＝ C / Co
<White turbidity temperature>
The test fuel and pure water were placed at room temperature and then added at a ratio of 1 pure water to 10 gasoline. And after shaking the mixture for 1 minute, it left still in a 30 degreeC thermostat for 1 hour or more, and used the gasoline which became a water saturated state as the test sample. Subsequently, 1 L of the test fuel is transferred to a 1 L glass bottle with a diameter of about 10 cm with an index attached to the inner bottom surface, and the whole container is cooled in ice water while stirring with a glass rod. Visual confirmation of the index was performed. FIG. 1A is a diagram showing a state that is determined to be cloudy by visual confirmation, and FIG. 1B is a diagram illustrating a state that is determined to be not cloudy.

  As shown in Table 2, the gasoline of Examples 1 and 2 has a smaller temperature dependency because the slope of the saturated water content approximate line is smaller than that of the comparative example. Therefore, the cloudiness temperature is lower, and it can be seen that the gasoline is less susceptible to cloudiness.

In the examples, it can be seen that the saturated moisture content, the approximate linear slope, and the cloudiness temperature at each temperature are all correlated with the saturated moisture temperature dependency coefficient K. Therefore, in consideration of these relationships and the mixing ratio of the base material, the mixing ratio of alkylate is set to 10 to 40% by volume, or the mixing ratio of the catalytic reformed gasoline having 7 carbon atoms is set to 20% by volume or less. In this way, the conventional gasoline having an octane number of 96 or more can be superior at the cloudiness temperature. In addition, considering the composition ratio of each base material, the aromatic hydrocarbon content is 40 vol% or less and the saturated hydrocarbon content is 40 vol% or more, which is superior to conventional gasoline in cloudiness temperature. Can have

Claims (4)

  Gasoline fuel characterized by having an aromatic hydrocarbon content of 40% by volume or less, a saturated hydrocarbon content of 40% by volume or more, a relative dielectric constant of 2.10 or less, and a research octane number of 96 or more. Composition. The gasoline fuel composition according to claim 1, wherein a saturated moisture temperature dependency coefficient K represented by the following formula is 250 or less.
Saturated water temperature dependency coefficient K = 3.5 × O + 7.3 × t + 3.3 × C9
O: Olefin content (volume%)
t: Toluene content (volume%)
C9: C9 aromatic hydrocarbon (volume%)   The gasoline fuel composition according to claim 1 or 2, wherein the mixing ratio of the alkylate is 10 to 40% by volume. The gasoline fuel composition according to any one of claims 1, 2, and 3, wherein a mixing ratio of the carbon-modified catalytic reformed gasoline is 20% by volume or less.