JPH0693275A - Gasoline composition - Google Patents

Abstract

PURPOSE:To provide a specific composition low in the ozone-forming capability of the exhaust gas resulting from its combustion because of the photochemical reactivity of exhaust gas, thus favorable in terms of dealing with photochemical smog. CONSTITUTION:The composition with the fuel ozone index defined by the formula [Ci is the concentration (wt.%) of nonmethane organic gas component i contained in the gasoline composition; MIRi is MIR value for the component i] falling at or below 3. To obtain this composition, the respective ozone indices for gasoline base oils such as alkylates, catalytically cracked gasolines, or light naphtha are determined, in advance, by calculation using the above- mentioned formula after separating, with e.g. gas chromatography, identifying and quantifying the components of the respective base oils; then, these base oils are combined, while considering their proportions (wt.%), so that the density (at 15 deg.C) come to <=0.783g/cm<3>, RON value >=89, MON value >=80, 10% distilling- off temperature <=70 deg.C, 50% distilling-off temperature <=125 deg.C and 90% distilling- off temperature <=180 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gasoline composition having a specific composition and having a low photochemical reactivity of exhaust gas after combustion, and a method for producing the same.

[0002]

2. Description of the Related Art When ultraviolet rays from the sun act on nitrogen oxides and hydrocarbons emitted from automobiles and other sources,
A photochemical oxidant mainly composed of ozone is produced. This product, called photochemical smog, is an environmental pollutant that causes acute damage to many people, such as eye and throat irritation, especially on windy days and in areas where air is likely to accumulate. .

Therefore, the emission amount of nitrogen oxides and hydrocarbons, which are one of the sources of photochemical smog, which are one of the main sources of photochemical smog, has been regulated conventionally.
The measures are being implemented. As a countermeasure, for the vehicle itself, the exhaust gas purification device has been improved,
As for the fuel, for example, in the case of gasoline, dirt in the intake system of the engine increases nitrogen oxides, hydrocarbons and carbon monoxide in the exhaust gas, and therefore a cleaning agent is added to gasoline to maintain the cleanliness of the intake system. Has been.

Conventional regulations have been regulations based on the total concentration of nitrogen oxides (NOx) and the total concentration of hydrocarbons (HC), but in recent years, a new index for more effectively preventing photochemical smog in the United States. In order to obtain the above, the measurement of ozone generation ability of automobile exhaust gas using a photochemical reaction model has been studied, and several methods have been proposed.

An example will be described.

The Relative Reactivity method approximates the effect of changes in exhaust gas on ozone generation, and is a simple linear method. This method is a method of estimating the change in the exhaust gas level of these groups in proportion to the change in the peak ozone concentration for one hour by grouping the hydrocarbons. The disadvantage of this approach is that it depends on the environmental conditions and that it becomes cumbersome as the number of hydrocarbons increases.

The Incremental Reactivity method is a method for estimating from the amount of change in ozone caused by a minute increase in hydrocarbons in a polluted environment. This Incremental
Reactivity can be determined experimentally, but it also depends on environmental conditions.

For all of these, the measured values cannot be obtained unless the environmental conditions are determined.

Maximum Incremental Reactivity (MI
Method R) is a method that reflects the maximum ozone production potential of hydrocarbons under certain environmental conditions. This approach is said to be suitable for providing indicators for use in regulatory measures. This is because the most effective measure for ozone reduction is to control the type of hydrocarbon that maximizes reactivity.

United States California Department of Atmospheric Resources (Califo
In the rnia Air Resources Board (CARB), the ozone generating ability of exhaust gas is calculated by the following equation using the MIR and used as an index of photochemical reactivity of exhaust gas.

Ozone generating capacity (gO ₃ / gNMOG) = Σ (NMOGi (g / mile) ×
MIRi (gO ₃ / gNMOG)) / ΣNMOGi (g / mile) [In the formula, NMOG is non-methane organic gas (Non-Methane O
rganic Gases) component i, that is, hydrocarbons containing 12 or less carbon atoms excluding methane in the exhaust gas and oxygen-containing hydrocarbon compounds having 5 or less carbon atoms such as ketones, aldehydes, alcohols, It is the amount of the component i of the non-methane organic gas such as ether, and MIRi is the MIR of the component i. The MIR values of various non-methane organic gases are shown in Table 5. This MIR value has been studied to improve the accuracy, and may be updated in the future.

The exhaust gas test applied here is a Federal Test Procedure (Federal Register / Vol.50, defined by the US Environmental Protection Agency (EPA)).
Follow No. 51).

If the vehicle and the fuel to be used are decided, the ozone generating ability is determined by collecting the exhaust gas by the above-mentioned test method and then measuring the total NMO.
The G component can be quantified after being separated and identified by gas chromatography or the like, and can be determined by the definition formula.

It is known that this ozone generation ability changes depending on the exhaust gas countermeasure device of the vehicle and the composition of the fuel.

[0015]

As described above, it has been found that it is effective to reduce the ozone generating ability of exhaust gas in order to prevent photochemical smog. Therefore, although technologies for exhaust gas countermeasures for vehicles have been developed and improved, further improvement of the composition of gasoline composition as a fuel has been demanded.

As a result of research to reduce the ozone-forming ability of exhaust gas, the present inventors have found that when a gasoline composition having a specific composition is used, the ozone-producing ability of exhaust gas decreases. Completed the invention.

[0017]

According to the present invention, the fuel ozone index defined by the following equation is 3.0 or less, preferably 2.5 or less,
More preferably, a gasoline composition having 2.0 or less is provided.

Fuel ozone index = Σ (Ci × MIRi) [where Ci is the concentration (% by weight) of the non-methane organic gas component i contained in the gasoline composition, and MIRi
Is the MIR of the non-methane organic gas component i. ] Non-methane organic gas means the number of carbons excluding methane, as mentioned above.
Hydrocarbon compounds containing 12 or less oxygen and 5 carbon atoms
The following oxygen-containing hydrocarbon compounds are meant as ketones, aldehydes, alcohols and ethers.

Table 5 shows the MIR values of various non-methane organic gases.
Shown in.

The hydrocarbon contained in the gasoline composition can be quantified after being separated and identified by gas chromatography or the like.

As a result of investigating the properties of the gasoline composition which gives the ozone generating ability of the exhaust gas, the properties which have been conventionally used for the gasoline composition, such as aromatic content%, olefin capacity%, and Volume% plus both,
Furthermore, it has been found that properties such as 90% distillation temperature have a low correlation with the ozone generating ability of exhaust gas.

It has been found that the fuel ozone index defined by the above equation has a good correlation with the exhaust gas ozone generation ability. Therefore, according to the present invention, it is possible to provide a gasoline composition in which the photochemical reactivity of exhaust gas is lower than that of conventional gasoline, that is, the generation of photochemical smog can be suppressed.

The fuel ozone index of a conventional gasoline composition is
Although it exceeds 3.0 and even reaches 4.5, the gasoline composition of the present invention has a composition in which the fuel ozone index is 3.0 or less, and the photochemical reactivity of exhaust gas is low.

The above gasoline composition can be prepared as follows.

Fuel ozone indicators as defined above, such as gasoline base stocks used in formulating gasoline compositions such as alkylate, catalytically cracked gasoline, light naphtha, toluene, reformed gasoline, methyl-t-butyl ether, etc. Are obtained in advance. These can be determined by quantifying the components of the gasoline base oil after separation and identification by gas chromatography or the like, and calculating by the above defined formula.

It is possible to achieve the required fuel ozone index of the gasoline composition by appropriately combining these base materials while considering their weight percentages so as to satisfy the following properties required for the gasoline composition. it can.

Density (15 ° C.) 0.783 g / cm ³ or less RON 89.0 or more MON 80.0 or more 10% distillation temperature 70 ° C. or less 50% distillation temperature 125 ° C. or less 90% distillation temperature 180 ° C. or less The gasoline composition of the invention includes an anti-knock agent, a surface ignition inhibitor, an antioxidant, a metal deactivator, an antifreezing agent, a corrosion inhibitor, a bactericidal agent, an antistatic agent, a lubricity imparting agent and a colorant. May be included.

[0028]

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

Examples 1-2 and Comparative Examples 1-2 Light naphtha, heavy naphtha, light alkylate, light cracked gasoline, cracked gasoline, toluene, o-xylene, heavy reformed gasoline, methyl-t-butyl ether, etc. A gasoline composition was prepared by appropriately using an appropriate amount of the gasoline base oil of Table 1 (Table 1). Table 2 shows the properties of these base oils.

[0030]

[Table 1]

[0031]

[Table 2]

Table 3 shows the results obtained by analyzing the gasolines of Examples 1 and 2 and Comparative Examples 1 and 2 by gas chromatography and calculating the fuel ozone index defined above. In addition, Table 3 also shows the results of analyzing the exhaust gas generated by using the gasoline of Examples 1 and 2 and Comparative Examples 1 and 2 as the fuel and determining the ozone generating ability.

[0033]

[Table 3]

In the vehicle used for this, the engine has a displacement
It was a 2200cc, in-line 4-cylinder, fuel-injected vehicle with a three-way catalyst and an automatic transmission specification. The operating conditions are Federal Test Procedure.
According to the conditions prescribed in. The same applies to the exhaust gas sampling method.

NMOG analysis is carried out by gas chromatography for hydrocarbons containing no oxygen, and
Aldehydes were measured by the Impinger HPLC method.

Comparative Examples 3 to 4 Table 4 shows the results of measuring the fuel ozone index and the ozone generating ability of conventional unleaded regular gasoline and unleaded high octane gasoline.

[0037]

[Table 4]

The MIRs adopted in the present invention for various non-methane organic gases are shown below. This MIR was announced by the Air Resources Board of California, USA (AIR-SOURCE # 9).
2-23).

[0039]

[Table 5] NMOG component MIR (gO ₃ / gNMOG) alkane Normal alkane methane (reference) 0.0148 ethane 0.25 propane 0.48 n-butane 1.02 n-pentane 1.04 n-hexane 0.98 n-heptane 0.81 n-octane 0.61 n-nonane 0.54 n -Decane 0.47 n-undecane 0.42 n-dodecane 0.38 n-tridecane 0.35 n-tetradecane 0.32 n-pentadecane 0.29 branched alkane 2-methylpropane 1.21 2,2-dimethylpropane 0.37 2-methylbutane 1.38 2,2-dimethylbutane 0.82 2, 3-dimethylbutane 1.07 2-methylpentane 1.53 3-methylpentane 1.52 2,2,3-trimethylbutane 1.32 2,2-dimethylpentane 1.40 2,3-dimethylpentane 1.51 2,4-dimethylpentane 1.78 3,3-dimethyl Pentane 0.71 2-Methylhexane 1.08 3-Methylhexane 1.40 2,2,4-Trimethylpentane 0.93 2,3,3-Trimethylpentane 1.20 2,3,4-Trimethylpentane 1.60 2,2-Dimethylhexane 1.20 2,3-Dimethylhexane 1.32 2,4-Dimethylhexane 1.50 2, 5-dimethylhexane 1.63 3,3-dimethylhexane 1.20 2-methylheptane 0.96 3-methylheptane 0.99 4-methylheptane 1.20 2,4-dimethylheptane 1.34 2,2,5-trimethylhexane 0.97 Other branched C ₉ H ₂₀ Alkane 1.14 Branched C ₁₀ H ₂₂ Alkane 1.01 Branched C ₁₁ Alkane 1.17 Branched C ₁₂ Alkane 1.23 Cycloalkane cyclopentane 2.38 Methylcyclopentane 2.82 Cyclohexane 1.28 t-1,2-Dimethylcyclopentane 1.85 1,3-Dimethylcyclopentane 2.55 Methylcyclohexane 1.85 Ethylcyclopentane 2.31 Ethylmethyl Cyclopentane 1.94 1c, 2t-3- trimethyl-cyclopentane 1.94 1,2,4-cyclopentane 1.94 dimethylcyclohexane 1.94 ethylcyclohexane 1.94 ethyl methyl cyclohexane 2.30 trimethylcyclohexane 2.30 C ₁₀ cycloalkane 1.78 C ₁₁ cycloalkane 1.91 C ₁₂ cycloalkane 1.68 alkenes ethene 7.29 propene 9.40 1-butene 8.91 2-butene 9.94 2-methylpropene 5.31 1-pentene 6.22 2-pentene 8.80 2-methyl-1-butene 4.90 3-methyl-1-butene 6.22 2-methyl-2-butene 6.41 1-Hexene 4.42 2-Hexene 6.69 3-Hexene 6.69 Methyl-1-pentene 4.42 Methyl-2-pentene 6.69 3,3-Dimethyl-1-butene 4.42 1-Heptene 3.48 2-Heptene 5.53 3-Heptene 5.53 3-Ethyl -2-Pentene 5.53 2,3-Dimethyl-2-pentene 5.53 3-Methyl-1-hexene 3.48 2-Methyl-2-hexene 5.53 4-Methyl-2-hexene 5.53 2-Methyl-3-hexene 5.53 3-Methyl-3-hexene 5.53 1-octene 2.69 2-octene 5.29 3-octene 5.29 4-octene 5.29 2,4,4-trimethyl-1-pentene 2.69 2,4,4-trimethyl-2-pentene 5.29 1-nonene 2.23 propadiene 7.29 1,3 - butadiene 10.89 2-methyl-1,3-butadiene 9.08 cyclopentadiene 7.66 cyclopentene 7.66 1-methyl-cyclopentene 5.67 3-methyl cyclopentene 5.67 cyclohexene 5.67 alpha-pinene 3.28 beta-pinene 4.41 alkyne ethyne 0.50 propyne 4.10 1-butyne 9.24 2-butyne 9.24 aromatic hydrocarbons as benzene 0.42 toluene 2.73 ethylbenzene 2.70 o- Silen 6.46 m-xylene 8.16 p-xylene 6.60 n-propylbenzene 2.12 i-propylbenzene 2.24 methylethylbenzene 7.20 1,2,3-trimethylbenzene 8.85 1,2,4-trimethylbenzene 8.83 1,3,5-trimethylbenzene 10.12 n-Butylbenzene 1.87 s-Butylbenzene 1.89 Diethylbenzene 6.45 1-Methyl-2-propylbenzene 6.45 1-Methyl-3-propylbenzene 6.45 C ₁₀ trialkylbenzene 9.07 Tetramethylbenzene 9.07 C ₁₁ monoalkylbenzene 1.70 1-Methyl-4- Isobutylbenzene 5.84 C ₁₁ dialkylbenzene 5.84 C ₁₁ trialkylbenzene 8.21 C ₁₂ monoalkylbenzene 1.55 C ₁₂ dialkylbenzene 5.34 C ₁₂ trialkylbenzene 7.50 Indane (C ₉ H ₁₀ ) 1.06 Methylindan 1.06 Naphthalene 1.18 Te Traline 0.95 Methylnaphthalene 3.27 2,3-Dimethylnaphthalene 5.13 Styrene 2.22 Aromatic oxygenated phenol 1.13 Cresol 2.31 Benzaldehyde 0.55 p-Tolualdehyde 3.32 Oxygenated alcohol Methanol 0.56 Ethanol 1.34 n-Propyl alcohol 2.26 Isopropyl alcohol 0.54 n-Butyl alcohol 2.69 Isobutyl alcohol 1.92 t-butyl alcohol 0.42 aldehydes formaldehyde 7.15 acetaldehyde 5.52 propionaldehyde 6.53 acrolein 6.77 n-butyraldehyde 5.26 crotonaldehyde 5.42 pentane aldehyde 4.41 hexane aldehyde 3.79 C ₇ aldehyde 3.32 ethers methyl t-butyl ether 0.62 ethyl t-butyl ether 1.98 ketone acetone 0.56 butanone 1.18

[0040]

EFFECT OF THE INVENTION By providing a gasoline composition having a fuel ozone index set lower than that of a conventional gasoline composition, the photochemical reactivity of exhaust gas of an automobile can be made lower than when a conventional gasoline composition is used. This is preferable in terms of countermeasures against photochemical smog.

Claims (1)

[Claims] 1. The fuel ozone index defined by the following formula is 3.0.
A gasoline composition that is: Fuel ozone index = Σ (Ci × MIRi) [where Ci is the concentration (% by weight) of the non-methane organic gas component i contained in the gasoline composition, and MIRi
Is the MIR of the non-methane organic gas component i. ]