JP4766655B2 - Gasoline composition - Google Patents

Description

  The present invention relates to a gasoline composition produced from a hydrocarbon such as petroleum and an oxygen-containing compound.

As one of the measures to achieve the CO ₂ emission reduction target by ratification of the Kyoto Protocol, fuel efficiency regulations of gasoline cars will be strengthened from 2010. To cope with this, it is planned to reduce fuel consumption by improving the compression ratio of automobiles by increasing the octane number of regular gasoline, which accounts for about 80% of gasoline automobile fuel. However, increasing the octane number of regular gasoline leads to higher olefins and higher aromaticity, which may cause deterioration of exhaust gas properties. In particular, the increase in distillation properties due to high aromatization may cause deterioration in engine startability when cold and deterioration in driving performance such as slack during acceleration.
On the other hand, the introduction of ethanol, which is a carbon-neutral biofuel that does not affect the increase or decrease of CO ₂ in the atmosphere, and ethyl tertiary butyl ether (ETBE) using this as a raw material has also been studied. Has been attracting attention (see Patent Documents 1 to 3).
In the study of oxygen-containing fuels so far, the main focus is on the impact on practical performance such as exhaust gas, operational performance and engine cleanliness of mixed gasoline.
JP 2004-285204 A JP 2004-292510 A JP 2004-292511 A

  The present invention appropriately adjusts the composition of the hydrocarbon in the production of the oxygenated fuel mixed gasoline, while significantly increasing the octane number at the time of mixing the oxygenated fuel, while suppressing the increase in the distillation properties due to the octane number improvement, By increasing both the research method octane number (RON) and motor method octane number (MON), it has excellent practical performance, ensuring driving performance at low temperatures such as acceleration at low temperatures, and anti-knock performance at medium, low speed, and high speed. The problem is to provide gasoline.

Although the octane number can be increased by using ethanol or ETBE as an oxygen-containing fuel and mixing it with gasoline, the improvement effect varies depending on the composition of the hydrocarbon. Generally, it is known that the one with less olefin or aromatic content enhances the effect of improving the octane number of the oxygen-containing fuel. Further, when the aromatic content is increased, the octane number generally increases, but the exhaust gas properties deteriorate and the cold operation performance deteriorates due to an increase in the 50% distillation temperature.
Thus, as a result of examining the effect of improving the octane number by mixing the oxygen-containing fuel, the present inventor has found that isoparaffins other than olefins have a considerable influence on the octane number improvement effect, and in particular, the carbon number 6 isoparaffin has a great influence. In addition, for paraffin that greatly contributes to ignition, it has been found that it is effective to improve the octane number effectively by arranging the ignition characteristics by the hydrocarbon bonding state expressed by the anti-knocking index. Moreover, the idea that the octane number after oxygen-containing fuel mixing increases notably by raising this anti-knocking index was obtained.

That is, the gasoline composition according to the present invention has a research octane number (RON) of 93 or more, a motor octane number (MON) of 83 or more, a 10% distillation temperature (T ₁₀ ) of 40 ° C. or more, and a 50% distillation. The temperature (T ₅₀ ) is 90 to 100 ° C., the 70% distillation temperature (T ₇₀ ) is 110 to 134 ° C., the 90% distillation temperature (T ₉₀ ) is 120 to 175 ° C., the olefin content is 1 to 15% by volume, 20% to 45% by volume of aromatics, 8.9% by volume or more of isoparaffins having 6 carbon atoms, 0.1 to 2.7% by mass of ethanol or ethyl t-butyl ether as oxygen content, anti-knocking index There -71.0～- 64 is 2.0, and the drivability index (DI) is one that satisfies the following equation (1).
DI = 1.5 × T ₁₀ + 3 × T ₅₀ + T ₉₀ + 11 × OX ≦ 530 (1)
Here, T ₁₀ represents 10% distillation temperature [° C.], T ₅₀ represents 50% distillation temperature [° C.], T ₉₀ represents 90% distillation temperature [° C.], and OX represents oxygen content [mass%]. Indicates.

  Further, the gasoline composition according to the present invention preferably has a vapor pressure at 37.8 ° C. of 65 kPa or less, a total sulfur content of 10 mass ppm or less, and a sulfur content by thiols of 1.5 mass ppm or less, Silver plate corrosion is preferably 1 or less and doctor test is negative from the viewpoints of reducing harmful substances, odor and corrosivity. Further, the gasoline composition of the present invention is obtained by blending gasoline before blending an oxygen-containing compound having a research octane number of 94 or more and a motor octane number of 84 or more with ETBE 1 to 8% or ethanol 1 to 3%. The gasoline composition obtained above is preferable.

  As described above, the paraffin hydrocarbon is adjusted so that the distillation property is within a certain value related to the oxygen-containing compound content as defined in the formula (1), and the anti-knocking index is a value within the range defined above. By adjusting the pressure, it is possible to ensure a high RON and a high MON while suppressing an increase in the distillation temperature of 50%, thereby providing a gasoline composition having excellent cold startability and operability and high energy conversion efficiency. be able to.

  The gasoline composition according to the present invention has a research octane number (RON) of 93 or more, preferably 94 to 100, particularly preferably 95 to 100. The motor method octane number (MON) is 83 or more, preferably 84 to 100, and particularly preferably 85 to 100. The measurement method of RON and MON is defined in JIS K2202.

  In the gasoline composition according to the present invention, the vapor pressure at 37.8 ° C. is naturally within the range of JIS standard (JIS K 2202: 44 to 93 kPa), preferably 65 kPa or less, more preferably 50 to 65 kPa, More preferably, it is 55-65 kPa. In this specification, the method for measuring the vapor pressure is defined in JIS K 2258.

The gasoline composition according to the present invention has a 10% distillation temperature (T ₁₀ ) of 40 ° C. or higher, preferably 47.5 to 50.0 ° C., and a 50% distillation temperature (T ₅₀ ) of 89 to 100 ° C. preferably 90 to 100 ° C., 70% distillation temperature _{(T 70)} is one hundred and ten to one hundred thirty-four ° C., preferably 112-125 ° C., 90% distillation temperature _{(T 90)} is one hundred and twenty to one hundred and seventy-five ° C., preferably It is 125-165 degreeC, More preferably, it is 130-155 degreeC. The distillation properties are defined in JIS K 2254.

In addition, the gasoline composition according to the present invention is required to have a drivability index (DI) satisfying the following relational expression.
DI = 1.5 × T ₁₀ + 3 × T ₅₀ + T ₉₀ + 11 × OX ≦ 530
Here, T ₁₀ represents a 10% distillation temperature [° C.], T ₅₀ represents a 50% distillation temperature [° C.], T ₉₀ represents a 90% distillation temperature [° C.], and OX contains a blended oxygen-containing compound. The quantity is given as oxygen content [% by mass].
DI is preferably 525 or less.

The aromatic content of the gasoline composition according to the invention is 20 to 45% by volume, preferably 25 to 40% by volume, in particular 27 to 38% by volume. Moreover, as an aromatic compound, it is preferable to make content of benzene into 1 volume% or less from a viewpoint of a harmful substance reduction further.
The olefin content is 1 to 15% by volume, preferably 5 to 14% by volume, and more preferably 9 to 13% by volume.
The isoparaffin content having 6 carbon atoms is 8.9% by volume or more. The isoparaffin having 6 carbon atoms is preferable as a gasoline component because it has a relatively low boiling point, a low vapor pressure, and a high octane number, and has an effect of increasing the octane number after addition, particularly when an oxygen-containing fuel is added. Preferably it is 9.0% or more, More preferably, it is 9.3 volume% or more.
In addition, content of each aromatic compound, an olefin compound, and a carbon number 6 isoparaffin was measured by the method prescribed | regulated to "How to obtain | require all the components by gas chromatography" of JISK2536-2.

  The anti-knocking index of the gasoline composition according to the present invention is -51.0 to -71.0. However, even if the anti-knocking index is too high, the effect of improving the octane number by the oxygen-containing compound fuel is reduced. It is 0--71.0, More preferably, it is -60.0--71.0, More preferably, it is -63.0--71.0.

The anti-knocking index is a numerical value obtained from the sum of anti-knocking indices between carbons constituting the hydrocarbon, and can be obtained as follows.
The anti-knocking index is given in Table 1 given for each combination obtained by the bonding state of one carbon and the bonding state of the other carbon that is the other carbon, and the number of carbon atoms between them. The numerical value shown shall be taken. The bonded state is a distinction between the first carbon (primary: p), the second carbon (secondary: s), and the third carbon (tertiary: t). These combinations are represented by symbols such as p1p. That is, when one carbon is the first carbon (p), the other carbons are also the first carbon (p), and there are zero carbon atoms between these first carbons, the symbol p1p And its anti-knocking index is -27.47. When the hydrocarbon compound (one molecule) contains n carbons, there are combinations of {(n-1) + (n-2)... + 2 + 1} carbons, and their anti-knocking index The sum is the antiknock index of the hydrocarbon compound. The anti-knocking index of paraffin hydrocarbons having 8 or more carbon chains is -138.8.

A method for obtaining the anti-knocking index will be described by taking 2-methylbutane as an example. For the sake of explanation, the carbons from the 1st position to the 4th position constituting 2-methylbutane are represented as C ^{1 to} C ⁴ as shown in Chemical Formula ^1, and the carbon branched to the 2nd position is represented as C ⁰ .

First, assuming that carbon C ⁰ is one carbon and carbons C ^{1 to} C ⁴ are other carbons, the antiknock index is obtained from Table 1, and the results are shown in Table 2.

Similarly, carbon C ^{1 to} C ⁴ is regarded as one carbon, and an anti-knocking index between carbons other than carbon C ⁰ is obtained. These combinations are summarized in Table 3 using the symbols in Table 1.

  Based on Table 3, when the sum of anti-knocking indexes in all combinations is calculated, 1 × {p2p} + 2 × {p3p} + 1 × {p1s} + 2 × {p2s} + 2 × {p1t} + 1 × {p2t} +1 X {s1t} = − 47.15, that is, the anti-knocking index of 2-methylbutane: −47.15 is obtained.

  The numerical values defined in Table 1 are obtained by parameterizing the chemical structure of 44 types of saturated hydrocarbons whose octane numbers are actually measured by the above-described method, and these parameters are weighted based on the actually measured octane number (RON). It has been quantified by regression analysis.

  The anti-knocking index of the substrate can be obtained by weighting the anti-knocking index of each saturated hydrocarbon compound contained in the substrate with its content. Specifically, first, the anti-knocking index of paraffin hydrocarbons contained in the substrate is obtained by the above-described method, or the anti-knocking index of each paraffin hydrocarbon is prepared in advance. Next, the content of each compound of paraffin hydrocarbon contained in the base material is quantitatively analyzed. Thereafter, [antiknocking index of each hydrocarbon compound] × [volume ratio% that the compound makes paraffin hydrocarbon in the base material] / 100 is obtained for each compound, and the sum is the antiknocking index of the base material.

  The anti-knocking index of the fuel can be obtained by weighting the anti-knocking index of the base material contained in the fuel by its content. Specifically, after obtaining the anti-knocking index of each base material, the [anti-knocking index of each base material] × [volume ratio% that the base material fills the entire fuel] / 100 is obtained for each base material, and the sum is obtained. Is the fuel anti-knocking index.

  The gasoline composition according to the present invention contains an oxygen-containing compound in an oxygen content of 0.1 to 2.7% by mass. A preferable content of the oxygen-containing compound is 0.5 to 2.5% by mass, particularly 0.6 to 2.3% by mass. As the oxygen-containing compound to be used, alcohol or ether is preferable. Specific examples of preferable alcohols include methanol, ethanol, and propanol. Examples of ethers include methyl t-butyl ether (MTBE), ethyl t-butyl ether (ETBE), and t-amyl ethyl ether (TAEE). .

  The sulfur content of the gasoline composition according to the present invention is preferably 10 ppm by mass or less, particularly preferably 0.1 to 5 ppm by mass. The sulfur content by thiols is preferably 1.5 ppm by mass or less, particularly preferably 0.1 to 1.2 ppm by mass, and the proportion of sulfur by thiols in the sulfur content is 30% or less, particularly 10 to 30%. It is preferable that

  Moreover, it is preferable that silver plate corrosion is 1 or less and a doctor test result is negative. Silver plate corrosion is affected by a very small amount of hydrogen sulfide, and the silver plate may be discolored at about 10 ppb. Thiols are organic sulfur compounds containing SH groups, chain thiols with SH groups added to chain paraffins, alicyclic thiols with SH groups added to cyclic paraffins, and SH groups added directly to aromatic rings. Containing aromatic thiols.

  Sulfur containing thiol in gasoline is contained in a relatively large amount in fluid catalytic cracking gasoline base and pyrolysis gasoline base, and details of the reduction method are described in Japanese Patent Application No. 2004-178210, which has already been filed by the inventors. No. ".

  The gasoline composition according to the present invention preferably contains less than 80% by volume, particularly 30 to 70% by volume, more preferably 40 to 70% by volume, of other gasoline substrates in the catalytically modified gasoline substrate. As other gasoline base materials, fluid catalytic cracking gasoline base materials, alkylate gasoline base materials, base materials obtained by desulfurizing straight-run naphtha, and the like can be used. Moreover, an oxygen-containing compound is mix | blended so that it may contain 0.1-2.7 mass% as oxygen content.

  The preferred blending amount of these gasoline base materials is 0 to 80% by volume, especially 30 to 60% by volume of fluid catalytic cracking gasoline base, 0 to 30% by volume of light reformed gasoline base, particularly 5 to 20% by volume. %, Heavy reformed gasoline base material 0 to 30% by volume, especially 5 to 10% by volume, alkylate gasoline base material 0 to 35% by volume, particularly 5 to 25% by volume, oxygen-containing gasoline base material (of ETBE) Case) About 0.5 to 15% by volume (within 0.1 to 2.7% by mass as oxygen content), especially 0.5 to 8% by volume, and 0 to 40% by volume in total of other base materials It is.

  Furthermore, the gasoline composition of the present invention may contain one or more fuel oil additives known in the art as needed. Although these compounding quantities can be selected suitably, it is preferable to maintain the total compounding quantity of an additive to 0.1 mass% or less normally. Examples of fuel oil additives that can be used in the gasoline of the present invention include phenolic, amine-based antioxidants, Schiff-type compounds, metal deactivators such as thioamide-type compounds, and organic phosphorus-based surfaces. Anti-ignition agents, detergent dispersants such as succinimides, polyalkylamines and polyetheramines, anti-icing agents such as polyhydric alcohols or their ethers, anionic surfactants, cationic surfactants, amphoteric surfactants, etc. And anti-static agents and colorants such as azo dyes.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited thereto.

In order to prepare the gasoline compositions of Examples and Comparative Examples, the following gasoline base materials were prepared.
ETBE: commercially available ethyl t-butyl ether having a purity of about 95% (manufactured by Chevron Chemical).
ETOH: Commercial fermented ethanol (99 degrees first grade, manufactured by Nippon Alcohol Sales Co., Ltd.).
LN: A light naphtha obtained by desulfurizing Middle East crude oil after distillation and having a sulfur content reduced to 1 mass ppm or less.
FCCG: Fluid catalytic cracking gasoline, light gasoline is separated by distillation so that 5% distillation temperature is 25.0-43.0 ° C and 95% distillation temperature is 55.0-80.0 ° C. Then, after desulfurizing heavy gasoline, it is mixed with light gasoline again to reduce the sulfur content to 10 ppm by mass or less.
ALKG: A hydrocarbon having a high isoparaffin content (alkylated gasoline) obtained by reacting (alkylating) a fraction mainly containing butylene and a fraction mainly containing isobutane with a sulfuric acid catalyst.
TOL: Toluene with a purity of 99.98% obtained by extracting aromatics from a catalytically modified gasoline with a sulfolane solvent and distilling it off.
Table 4 shows the properties of the gasoline base material.

The gasoline base materials shown in Table 4 were blended at the blending ratio shown in the upper part of Table 5 to prepare gasolines to be Comparative Example 1 and Examples 1 and 2. Table 5 shows the properties of the prepared gasoline.
Regarding the properties shown in Tables 2 and 3, the research method octane number and motor method octane number were measured according to JIS K 2202, the vapor pressure was measured according to JIS K 2258, and the distillation property was measured according to JIS K 2254. The sulfur content was measured by the microcoulometric titration method of JIS K2541. Sulfur content (sulfur equivalent) by thiols was measured by gas chromatography using a Shimadzu gas chromatograph equipped with an ANTEK sulfur chemiluminescence detector that selectively detects and quantifies sulfur compounds by chemiluminescence. . The hydrocarbon component composition of aromatic, olefin and isoparaffin was measured in accordance with JIS K 2536-2 “How to obtain all components by gas chromatography” using a PIONA device manufactured by Hured Packard. Silver plate corrosion is the cylinder method (jet fuel) of JIS K2513 (Petroleum products-Copper plate corrosion test method: corresponding ASTM D130). Instead of the copper plate, “14. Silver plate of JIS K2276 (Petroleum product-Aviation fuel oil test method)” The silver plate used in the “corrosion test method” was evaluated. The test temperature is 50 ° C. and the test time is 3 hours. The doctor test was measured according to JIS K 2276.
The oxygen content was calculated by multiplying the blending amount of the oxygen-containing compound (after mass conversion) by the proportion of oxygen contained in the oxygen-containing compound.

Further, an acceleration performance test was performed using three test cars A, B, and C having the specifications shown in Table 6 using the chassis dynamometer apparatus using the gasolines of Examples 1 and 2 and Comparative Example 1. In the test, after the vehicle was kept in a cold machine (25 ° C.) state, when the accelerator opening was accelerated up to 50% by the automatic driving device (Horiba Seisakusho, ADS7000), the initial speed was 0 to 50 ( km / hour) until the vehicle speed was reached. The results (acceleration time reduction rate) were compared based on the difference in acceleration time relative to the arrival time when using the commercial regular gasoline of the reference example. The results are also shown in Table 3. The acceleration time reduction rate of the test gasoline was obtained from the following equation.
Acceleration time reduction rate = (reference example arrival time−test gasoline arrival time) ÷ (reference example arrival time) × 100

  The gasoline composition of the present invention uses an oxygen-containing compound and finely adjusts the distillation properties, the composition of the paraffin component, etc., so that it has a high octane number and has practical performance such as a cold acceleration performance of a vehicle. Can be held. Therefore, an excellent gasoline composition for automobiles can be provided.

Claims (4)

10% distillation temperature is 40 ° C or higher, 50% distillation temperature is 90-100 ° C, 70% distillation temperature is 110-134 ° C, 90% distillation temperature is 120-175 ° C, and olefin content is 1-15 volumes. %, Aromatic content is 20 to 45% by volume, carbon number 6 isoparaffin content is 8.9% by volume or more, and ethanol or ethyl t-butyl ether is contained in an oxygen content of 0.1 to 2.7% by mass. , research octane number is 93 or more, the motor octane number is 83 or more, the anti-knock index -71.0～- 64.0, and the drivability index (DI) satisfies the following formula (1) Gasoline composition, characterized by
DI = 1.5 × T ₁₀ + 3 × T ₅₀ + T ₉₀ + 11 × OX ≦ 530 (1)
(Here, T ₁₀ represents a 10% distillation temperature [° C.], T ₅₀ represents a 50% distillation temperature [° C.], T ₉₀ represents a 90% distillation temperature [° C.], and OX represents an oxygen content [mass%]. ]
  The gasoline composition according to claim 1, wherein the vapor pressure at 37.8 ° C is 65 kPa or less.   The gasoline composition according to claim 1 or 2, wherein the total sulfur content is 10 mass ppm or less, the sulfur content by thiols is 1.5 mass ppm or less, the silver plate corrosion is 1 or less, and the doctor test result is negative.   The gasoline composition according to any one of claims 1 to 3, comprising a gasoline having a research octane number of 94 or more and a motor octane number of 84 or more and ETBE of 1 to 8% or ethanol of 1 to 3%.