JP2007246744A - Unleaded high-octane-number gasoline - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an unleaded high-octane-number gasoline excellent in cleaning property of interior of an engine while using a heavy catalytically reformed gasoline as a high-octane-number base material. <P>SOLUTION: The unleaded high-octane-number gasoline is obtained by compounding 2-60 vol.% gasoline base material and 0.5-10.0 vol.% ethanol (EtOH), wherein the gasoline base material is obtained from a catalytically reformed gasoline which has a polycyclic aromatic content index Y represented by a definite formula of ≤20 and is obtained by a catalytic reforming treatment of a desulfurized heavy naphtha fraction having definite properties which is obtained by a desulfurization treatment of a heavy straight-run naphtha having definite properties. The unleaded high-octane-number gasoline has a definite research octane number, a definite motor octane number, a definite 50 vol.% distillation temperature, a definite 90 vol.% distillation temperature and definite Reid vapor pressure and contains 50-1,000 mass ppm cleaning agent. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to unleaded high-octane gasoline, and more specifically, to provide unleaded high-octane gasoline that is excellent in cleanliness in the engine such as the combustion chamber and intake valve and can further reduce CO and THC in exhaust gas. It is what.

In recent years, environmental pollution due to exhaust gas from automobiles and the like has been attracting attention from the viewpoint of environmental improvement, and various efforts have been made to reduce exhaust gas from the fuel surface. Specifically, it is considered effective to reduce engine exhaust gas or evaporated gas from a fuel tank.
The engine exhaust gas contains CO and THC (Total Hydro Carbon: hydrocarbon). When CO is absorbed even by the human body, it binds with hemoglobin and inhibits oxygen transport of red blood cells, causing a great adverse effect. It has been known. On the other hand, methane in THC is thought to contribute to global warming, and non-methane components are thought to contribute to the generation of photochemical smog. For this reason, it is important to reduce the exhaust gas from the automobile engine.

  In general, in order to reduce exhaust gas, it is known that installation of an exhaust gas purification catalyst system in an automobile is effective. It is also known that reducing the sulfur content of the fuel leads to a longer life of the exhaust gas purification catalyst system and is effective in reducing exhaust gas. On the other hand, keeping the inside of the engine clean by improving the fuel oil is also considered effective in reducing exhaust gas. Specifically, it is considered effective to suppress intake valve deposit (IVD) and combustion chamber deposit (CCD).

  Furthermore, reformed gasoline used as a high-octane base material in the production of unleaded high-octane gasoline contains a lot of aromatic components, but it is known that IVD tends to increase when a lot of aromatic components are contained. (For example, refer nonpatent literature 1). Generally, a detergent such as polyetheramine or polyisobutene is added to reduce the IVD, but the CCD tends to increase when the detergent is added. In view of this, as a fuel that suppresses both IVD and CCD of a gasoline engine, a fuel that defines the aromatic content and the distillation property of gasoline has been proposed (see, for example, Patent Document 1). However, this technique has a problem in that the gasoline yield decreases because the blending amount of the heavy fraction is reduced in order to make the distillation property of gasoline light.

  Therefore, in order to prevent a decrease in gasoline yield, the intake valve deposit (IVD (Inlet Valve Deposit)) and the combustion chamber deposit (CCD (Combustion Chamber Deposit)) are suppressed while blending heavy fractions. In addition, it is desired to provide unleaded high octane gasoline that can further reduce CO and THC in exhaust gas.

Furthermore, in consideration of the recent global warming problem, in addition to the above, provision of fuel with reduced CO ₂ emissions is also desired. As a measure against CO ₂ emissions, it is conceivable to mix ethanol derived from biomass or ETBE derived from it into gasoline. However, in order to increase the amount of CO ₂ reduction, if you try to add ethanol to gasoline more, the azeotropic phenomenon of hydrocarbon and ethanol becomes noticeable and the distillation curve becomes distorted, which may deteriorate the drivability. It is known. In order to avoid this, it can be considered that ETBE obtained by reacting ethanol with isobutylene is blended with gasoline, but from the viewpoint of CO ₂ reduction by biomass mixing, it is necessary to blend a very large amount of ETBE, The economy of gasoline production will be inferior.

SAE Paper, Society of Automotive Engineers 922217 JP 2000-204383 A

  The object of the present invention is an unleaded high octane gasoline that can suppress both IVD and CCD of a gasoline engine and can further reduce CO and THC in exhaust gas while using a heavy fraction as a high octane base. Is to provide.

As a result of intensive studies, the present inventors have obtained catalytic reformed gasoline using a desulfurized heavy naphtha fraction having a constant property, and further, the polycyclic aromatic content of the catalytic reformed gasoline is within a certain range. In order to ensure CO ₂ reduction by blending ethanol and ethyl tertiary butyl ether, it is prepared in such a way that the content is gradually reduced as the number of rings increases. It has been found that even if it is blended in gasoline, it is possible to prescribe gasoline economically without causing deterioration in drivability. In addition, the mixture of ethanol and ETBE has excellent properties as an octane booster. Increasing the amount of these blends often has a positive impact on vehicle performance such as good driving performance and good cleanliness. I found out.

That is, the present invention provides the following lead-free high octane gasoline.
(1) A desulfurized heavy naphtha fraction having a sulfur concentration of 5 mass ppm or less and a nitrogen concentration of 5 mass ppm or less, obtained by desulfurizing a heavy straight-run naphtha having a 90% by volume distillation temperature of 160 ° C. or less. 2 to 60% by volume of a gasoline base material obtained from catalytically reformed gasoline obtained by catalytic reforming and having a polycyclic aromatic content index Y represented by the following formula (I) of 20 or less, ethanol (EtOH) In an amount of 0.5 to 10.0% by volume, 0.5 to 15.0% by volume of ethyl tertiary butyl ether (ETBE), and satisfying the following properties 1) to 6): Octane gasoline.
Y = (0.002 × 3R-A) + (0.01 × 4R-A) + (0.07 × 5R-A) + (0.2 × 6R + -A)… (I)
[In the formula, 3R-A is a 3-ring aromatic content, 4R-A is a 4-ring aromatic content, 5R-A is a 5-ring aromatic content, 6R + -A is an aromatic content of 6 or more rings (both in gasoline) (Ppm by mass)
1) Research octane number is 97-105,
2) Motor method octane number is 85-92,
3) 50% by volume distillation temperature is 75-110 ° C,
4) 90% volume distillation temperature is 180 ℃ or less,
5) Reed vapor pressure is 45-93kPa,
6) The unleaded high-octane gasoline according to (1) above, which contains a detergent in the range of 50 to 1000 ppm by mass (2) and further satisfies the following properties 1) to 7).
1) Distillation at 70 ° C is 18-40% by volume
2) Aromatic content 45% or less 3) Olefin content 30% or less 4) Benzene content 1% or less 5) Sulfur content 10 mass ppm or less 6) Gas-liquid at 60 ° C Ratio (V / L) is 30-70
7) Density at 15 ° C is 0.68 to 0.78 g / cm ³
(3) The unleaded high octane gasoline according to (1) or (2) above, wherein the gasoline base material is obtained by debenzene treatment of the catalytic reformed gasoline.

  According to the lead-free high-octane gasoline of the present invention, it is possible to simultaneously suppress the generation of deposits in the combustion chamber and the intake valve in the engine without reducing the gasoline, and improve the cleanliness in the engine. Furthermore, the amount of harmful components such as CO and THC contained in the exhaust gas can be further reduced, and the air environment can be preserved.

Hereinafter, the contents of the present invention will be described in more detail.
The catalytically reformed gasoline used in the lead-free high octane gasoline of the present invention is obtained by desulfurizing heavy straight-run naphtha having a 90% by volume distillation temperature of 160 ° C. or less obtained by an atmospheric distillation apparatus, and a sulfur concentration of 5 mass. The desulfurized heavy naphtha was subjected to catalytic reforming treatment after setting the nitrogen concentration to 5 ppm or less, and the polycyclic aromatic content index Y represented by the following formula (I) to 20 or less.
Y = (0.002 × 3R-A) + (0.01 × 4R-A) + (0.07 × 5R-A) + (0.2 × 6R + -A)… (I)
[In the formula, 3R-A is a 3-ring aromatic content, 4R-A is a 4-ring aromatic content, 5R-A is a 5-ring aromatic content, 6R + -A is an aromatic content of 6 or more rings (both in gasoline) (Ppm by mass)

  The formula (I) of the polycyclic aromatic content index is an empirical formula obtained from the relationship between the content of the polycyclic aromatic content and the deposit amount in the engine, and includes three rings, four rings, five rings, and six rings. The higher the value, the higher the value. This indicates that the increase of harmful components in the exhaust gas and the generation of deposits in the engine become higher as the polycycle increases. The polycyclic aromatic content index Y in the catalytic reformed gasoline is 20 or less, preferably 15 or less, more preferably 12 or less. If it is 20 or less, an increase in engine deposits and an increase in harmful components in exhaust gas can be prevented.

The polycyclic aromatic content is a value obtained by quantification according to the number of rings by the gas chromatographic method shown below, and the quantification method is an absolute calibration curve method using a typical standard sample according to the number of rings. . That is, a dimethyl silicon capillary column with a length of 30 m and an inner diameter of 0.25 mm is used as the column, the detector is a hydrogen ionization detector (FID), the carrier gas is helium at a flow rate of 1.3 ml / min, splitless injection, inlet temperature This is a value measured by raising the column temperature from the initial temperature of 50 ° C. to the final temperature of 350 ° C. under the conditions of 300 ° C. and detector temperature of 350 ° C.

  The 90 vol% distillation temperature range of the heavy straight-run naphtha used for obtaining desulfurized heavy naphtha in the present invention is 160 ° C or lower, preferably 135 to 160 ° C, more preferably 140 to 150 ° C. By setting the 90 vol% distillation temperature to 160 ° C or less, it is possible to prevent the catalytic reformed gasoline from becoming heavy. Furthermore, by setting the 90% by volume distillation temperature range to 135 ° C. or higher, the catalytic reformed gasoline when the benzene fraction is removed can be increased in octane number, which is more preferable. This distillation property is a value measured according to JIS K 2254.

In addition, desulfurization treatment of heavy straight-run naphtha is carried out in the presence of a desulfurization catalyst in which a group VI or VIII metal is supported on an inorganic carrier, with a reaction pressure of 0.1 to 10 MPa, preferably 1 to 3 MPa, and a reaction temperature of 200 to 200. The desulfurization reaction is performed at 450 ° C., preferably 250 to 350 ° C., and the liquid space velocity (LHSV) is 0.1 to 20 hr−1, preferably 0.5 to 10 hr−1.
The resulting desulfurized heavy naphtha has a sulfur concentration of 5 ppm by mass or less, preferably 1 ppm by mass or less, and a nitrogen concentration of 5 ppm by mass or less, preferably 1 ppm by mass or less. When the sulfur concentration and the nitrogen concentration are each 5 ppm by mass or less, the deactivation of the catalytic reforming catalyst can be prevented. The sulfur concentration is a value measured according to JIS K2541 microcoulometric titration method, and the nitrogen concentration is a value measured according to JIS K2609 chemiluminescence method.

  Contact reforming treatment of desulfurized heavy naphtha is performed by various contact reforming methods (Platform forming method, Magna forming method, Aromaizing method, Reni forming method, Food reforming method, Ultra forming method, Power forming method, etc.) The desulfurized heavy naphtha can be subjected to contact treatment with a catalyst (for example, a material in which platinum, rhodium and chlorine are supported on an alumina carrier) in a hydrogen stream under high temperature and pressure.

The lead-free high-octane gasoline of the present invention is produced using a catalytically modified gasoline obtained by catalytic reforming of the desulfurized heavy naphtha as a base material. Although a manufacturing method in particular is not restrict | limited, Generally, it can manufacture using the following various fractions. Ie;
(A) Debenzene-catalyzed reformed gasoline obtained by removing a benzene fraction from the above-mentioned catalytic reformed gasoline by distillation;
(B) The above catalytic reformed gasoline is separated by distillation into a light fraction, a benzene fraction, and a heavy fraction. The light fraction (debenzene light catalytic reformed gasoline) and the heavy fraction (debenzene heavy) Quality contact reforming gasoline),
(C) Aromatic main contact reforming gasoline mainly composed of toluene or aromatics having 9 or more carbon atoms obtained by distillation or extraction of the above catalytic reforming gasoline (d) Normal pressure residue from kerosene / light oil Petroleum fractions, preferably heavy gas oil or vacuum gas oil, are conventionally known catalytic cracking methods, especially fluid catalytic cracking methods (UOP method, shell two-stage method, flexi cracking method, ultra ortho flow method, Texaco method, Gulf method, Ultracat cracking method, RCC method, HOC method, etc.) Distill the catalytically cracked gasoline obtained by cracking with solid acid catalyst (eg silica / alumina blended with zeolite) Light catalytic cracking gasoline,
(E) an alkylate obtained by reacting isobutane with a lower olefin (butene, propylene, etc.) in the presence of an acid catalyst (sulfuric acid, hydrogen fluoride, aluminum chloride, etc.),
(F) C4 fraction mainly composed of butane and butenes obtained by distillation at the time of atmospheric distillation of crude oil, crude oil or the like, during the production of reformed gasoline, or during the production of cracked gasoline,
(G) Isomerate obtained by isomerization of linear lower paraffinic hydrocarbon, or isopentane obtained by precision distillation of isomerate,
Etc. are used as gasoline base materials.

  The unleaded high octane gasoline of the present invention further contains ethyl tertiary butyl ether (ETBE) and ethanol (EtOH). Ethanol (EtOH) has a purity of 92.0% by volume or more, preferably 95.0% by volume or more, and more preferably 99.5% by volume or more. As ETBE and ethanol, all those obtained from known production methods can be used, and the production method is not particularly limited.

The following examples are given as specific examples for producing the unleaded high octane gasoline of the present invention by appropriately selecting and using the various fractions as described above. Ie;
(A ′) 2 to 60% by volume of debenzene-catalyzed reformed gasoline having a research octane number of 100 or more, a motor method octane number of 88 or more, a lead vapor pressure of 28 kPa or more, and a boiling point range of 30 to 215 ° C., or (b ′ ) I) Research method octane number of 78 or more, motor method octane number of 70 or more, Reed vapor pressure of 85 kPa or more, boiling point range of 26-80 ° C debenzene light catalytic reformed gasoline 0-15 vol%, and ii) Research 2-50% by volume of debenzene heavy contact reformed gasoline with a method octane number of 101 or higher, motor method octane number of 89 or higher, Reed vapor pressure of 3 kPa or higher, and boiling point range of 90-215 ° C, or (c ') above contact 2 to 50% by volume of aromatic main catalytic reformed gasoline mainly composed of toluene or aromatics having 9 or more carbon atoms, obtained by distillation or extraction of reformed gasoline or debenzene-heavy catalytic reformed gasoline And (b ′) i) and (d ′) 5 of light catalytic cracking gasoline having a research octane number of 93 or higher, a motor octane number of 81 or higher, a Reid vapor pressure of 90 kPa or higher, and a boiling point range of 25 to 110 ° C. ~ 55% by volume,
The unleaded high octane gasoline of the present invention can be produced by blending so that the unleaded high octane gasoline obtained can have a predetermined property.
In addition, in the formulation of each substrate as described above,
(E ') 0 to 40 vol% alkylate,
Can be further blended to produce the lead-free high octane gasoline of the present invention.

The lead-free high-octane gasoline of the present invention is a gasoline base material obtained from the catalytic reformed gasoline, for example, at least one of (a) to (c) (or (a ′) to (c ′)) of the above examples. Are contained as essential fractions, and the total amount is 2 to 60% by volume, preferably 20 to 60% by volume. If the content is 2% by volume or more, the octane number of the unleaded high-octane gasoline can be improved, and if it is 60% by volume or less, the unleaded high-octane gasoline can be prevented from becoming heavy.
The unleaded high octane gasoline of the present invention further contains ethanol. The ethanol content is in the range of 1% to 15% by volume, preferably 3% to 15% by volume, based on the total gasoline. If it is 1% by volume or more, the advantage of improving the octane number by blending with ethanol can be obtained, and if it is 15% by volume or less, the evaporation characteristics do not change significantly due to the azeotropic phenomenon with other gasoline base materials. The proper drivability can be secured.
The unleaded high octane gasoline of the present invention further contains 1 to 25% by volume, preferably 3 to 20% by volume, more preferably 5 to 18% by volume of ETBE. If the blending amount of ETBE is within the above range, it is possible to reduce CO, THC, etc. in the exhaust gas without fear of an adverse effect on fuel consumption due to a decrease in calorific value.
The other fractions are appropriately selected, and the present invention is carried out by appropriately setting and blending their blending amounts according to the properties of each fraction so that the resulting unleaded high-octane gasoline has a predetermined property. Unleaded high octane gasoline can be produced.

  The unleaded high octane gasoline of the present invention has a research octane number of 97 to 105, preferably 98 to 103, and a motor octane number of 85 to 92, preferably 86 to 90. If the research octane number is 97-105, it is possible to maintain high driving performance as a so-called premium-grade high-octane gasoline. can do. The research method octane number and the motor method octane number are values measured in accordance with JIS K 2280.

  The lead-free high octane gasoline of the present invention has a 50% by volume distillation temperature (T50) of 75 to 110 ° C, preferably 85 to 100 ° C, and a 90% by volume distillation temperature (T90) of 180 ° C or less, preferably 110%. ~ 170 ° C. When the distillation temperature is within the above range, it is possible to prevent a problem in starting performance, operability, and acceleration. These distillation properties are values measured in accordance with JIS K 2254.

  The lead vapor pressure of the unleaded high octane gasoline of the present invention is 45 to 93 kPa, preferably 66 to 75 kPa. By setting the lead vapor pressure to 93 kPa or less, the amount of evaporative gas can be reduced, and by setting it to 45 kPa or more, it is possible to prevent the low temperature startability and warm-up performance from being deteriorated. The reed vapor pressure is a value measured according to JIS K 2258.

  The unleaded high octane gasoline of the present invention has a 70 ° C distillate (E70) of 18 to 40% by volume, preferably 20 to 40% by volume. If E70 is within the above range, it is possible to prevent a problem in starting performance, drivability and acceleration. These distillation properties are values measured in accordance with JIS K 2254.

  The aromatic content of the unleaded high octane gasoline of the present invention is 45% by volume or less, preferably 5 to 45% by volume. When the aromatic content is within 45% by volume, an increase in harmful components in the exhaust gas can be prevented. The aromatic content is a value measured according to the Petroleum Institute method JPI-5S-33-90 (gas chromatographic method).

  The olefin content of the unleaded high octane gasoline of the present invention is 30% by volume or less, preferably 5 to 25% by volume. When the olefin content is within 30% by volume, it is possible to prevent a decrease in oxidation stability. The olefin content is a value measured according to the Japan Petroleum Institute method JPI-5S-33-90 (gas chromatographic method).

  The lead-free high octane gasoline of the present invention has a benzene content of 1% by volume or less, preferably 0.8% by volume or less. If the benzene content is within 1% by volume, there is a possibility that the increase in benzene concentration in the atmosphere can be prevented and environmental pollution can be reduced. The benzene content is a value measured according to the Petroleum Institute method JPI-5S-33-90 (gas chromatographic method).

  The lead content of the lead-free high octane gasoline of the present invention is 10 ppm by mass or less, preferably 8 ppm by mass or less. If this sulfur content is 10 mass ppm or less, there is a possibility that the exhaust gas purification catalyst capacity can be prevented from being lowered and the concentration of CO and THC in the exhaust gas can be prevented from increasing. The sulfur content is a value measured in accordance with JIS K2541.

  The gas-liquid ratio (V / L) at 60 ° C. of the unleaded high octane gasoline of the present invention is 30 to 70, preferably 30 to 60. When this V / L is 30 or more, good startability can be ensured. In addition, by setting V / L to 70 or less, there is a possibility that defects in acceleration and drivability can be reduced. The V / L is a value measured according to ASTM D 2533-93a.

Density at 15 ℃ unleaded high-octane gasoline of the present invention, 0.68~0.78g / cm ^3, preferably 0.69~0.76 g / cm ^3. When this density is 0.68 g / cm ³ or more, good fuel consumption can be ensured. Further, by setting the density to 0.78 g / cm ³ or less, high-density aromatics can be reduced, and the amount of aromatics discharged into the atmosphere by exhaust gas can be reduced. This density is a value measured in accordance with JIS K 2249.

  In the lead-free high-octane gasoline of the present invention, the ratio of aromatics having 9 or more carbon atoms to the total aromatics (hereinafter also referred to as (C9 + A) / TA) is 0.80 or less, preferably 0.10 to 0.00. 80. It is preferable that the ratio of the aromatic component having 9 or more carbon atoms and the total aromatic component is 0.80 or less because it is possible to prevent the smoldering property of the plug from being lowered. The aromatic content is a value measured in accordance with the Petroleum Institute Method JPI-5S-33-90 (gas chromatographic method).

  A detergent such as polyetheramine, polyalkylamine, polyisobuteneamine, and succinimide is added to the lead-free high octane gasoline of the present invention. The addition amount is 50 to 1000 ppm by mass, preferably 100 to 500 ppm by mass. If the addition amount is 50 mass ppm or more, an increase in IVD can be prevented, and if it is within 1000 mass ppm, an increase in CCD can be prevented. When the above-mentioned constant amount of detergent is added, the generation of CCD can be effectively suppressed in combination with the effect of suppressing the generation of deposits in the engine of the catalytic reformed gasoline used in the present invention.

  The lead-free high-octane gasoline of the present invention can further contain various additives as required. Such additives include phenolic and amine antioxidants, metal deactivators such as thioamide compounds, surface ignition inhibitors such as organophosphorus compounds, long chain alkylamines, amides, imides and their derivatives. Friction modifiers (FM), antifreezing agents such as polyhydric alcohols and their ethers, organic acid alkali metal and alkaline earth metal salts, auxiliary alcohols such as higher alcohol sulfates, anionic surfactants, cations Well-known fuel additives such as antistatic agents such as system surfactants and amphoteric surfactants, rust inhibitors such as alkenyl succinates, and colorants such as azo dyes can be mentioned. These can be added alone or in combination. The addition amount of these fuel additives is arbitrary, but usually the total addition amount is preferably 0.1% by mass or less.

  The content of the present invention will be described in more detail with reference to Examples and Comparative Examples below, but the present invention is not limited thereto.

Examples and Comparative Examples Table 1 shows properties of desulfurized heavy naphtha, and Table 2 shows properties of catalytic reformed gasoline obtained by catalytic reforming of the desulfurized heavy naphtha. In Tables 1 and 2, desulfurized heavy naphtha α and catalytically reformed gasoline 1 obtained therefrom satisfy the properties of the present invention. On the other hand, desulfurized heavy naphtha β and catalytically reformed gasoline 2 obtained therefrom depart from the properties of the present invention.
Tables 3 and 4 show the properties, composition, and names of gasoline base materials used in the production of unleaded high-octane gasoline. Then, the gasoline base materials shown in Tables 3 and 4 were mixed at the ratio shown in Table 5 to produce unleaded high octane gasoline, and various performance evaluation tests described below were conducted.
The density in the table was measured by JIS K 2249, and the aromatic content, olefin content, and benzene content were measured by the Petroleum Institute method JPI-5S-33-90 (gas chromatographic method). In addition, a polyisobuteneamine-based detergent was used as the detergent.

  Intake valve deposit (IVD) test and combustion chamber deposit (CCD) test using a 2.5-liter, multi-point injection (MPI) type vehicle with 60-100 km / h acceleration / deceleration x 1,500 cycles The test was carried out under the conditions of 8,000km. The method is described below, and the results are shown in Table 5.

(IVD test)
Evaluation was made based on the weight of the deposit (IVD) attached to the intake valve and the IVD score (Rating: CRC No. 16) obtained by weighing the intake valve weight before and after operation. The rating value indicates that the larger the numerical value, the smaller the IVD amount.
(CCD test)
After the IVD test, the deposit (CCD) adhered to the cylinder head and the piston top was collected and weighed.

(Plug smoldering test)
Using a vehicle with a total displacement of 2L, MPI method, automatic transmission (AT), and a test temperature condition of -10 ° C, about 30 minutes per cycle (engine start ⇒ 10-20 km / h acceleration / deceleration repeated 10 times ⇒ 28 The degree of fouling of the plug was measured by measuring the insulation resistance of the plug. It was determined that plug smoldering occurred when the plug insulation resistance value was 100 MΩ or less.

(Exhaust gas test)
The exhaust gas test was conducted using a domestic passenger car (total displacement 2 L, MPI system, automatic transmission (AT), three-way catalyst installed), chassis dynamometer, acceleration / deceleration of 60-100 km / h x 1,500 cycles ( After running for 8,000 km), an exhaust gas test in 11 mode was conducted to measure carbon monoxide (CO) and total hydrocarbons (THC).

  As specifically shown in the examples, deposits are particularly prevented from adhering to the intake valves. Therefore, the present invention is excellent in cleanliness inside the engine and can maintain the air environment while using heavy contact reformed gasoline as a high octane base material.

Claims (3)

Catalytic reforming of desulfurized heavy naphtha fraction with sulfur concentration of 5 mass ppm or less and nitrogen concentration of 5 mass ppm or less, obtained by desulfurization of heavy straight-run naphtha with 90 vol% distillation temperature of 160 ° C or less 2 to 60% by volume of a gasoline base material obtained from a catalytically reformed gasoline having a polycyclic aromatic content index Y represented by the following formula (I) obtained by the treatment of 20 or less and ethanol (EtOH) of 0. A lead-free high-octane gasoline containing 5 to 10.0% by volume, 0.5 to 15.0% by volume of ethyl tertiary butyl ether (ETBE), and satisfying the following properties 1) to 6).
Y = (0.002 × 3R-A) + (0.01 × 4R-A) + (0.07 × 5R-A) + (0.2 × 6R + -A)… (I)
[In the formula, 3R-A is a 3-ring aromatic content, 4R-A is a 4-ring aromatic content, 5R-A is a 5-ring aromatic content, 6R + -A is an aromatic content of 6 or more rings (both in gasoline) (Ppm by mass)
1) Research octane number is 97-105,
2) Motor method octane number is 85-92,
3) 50% by volume distillation temperature is 75-110 ° C,
4) 90% volume distillation temperature is 180 ℃ or less,
5) Reed vapor pressure is 45-93kPa,
6) Contains detergent in the range of 50 to 1000 ppm by mass The unleaded high octane gasoline according to claim 1, further satisfying the following properties 1) to 7).
1) Distillation at 70 ° C is 18-40% by volume
2) Aromatic content 45% or less 3) Olefin content 30% or less
4) Benzene content is 1 vol% or less 5) Sulfur content is 10 mass ppm or less 6) Gas-liquid ratio (V / L) at 60 ° C is 30 to 70
7) Density at 15 ° C is 0.68 to 0.78 g / cm ³   The lead-free high-octane gasoline according to claim 1 or 2, wherein the gasoline base material is obtained by debenzene treatment of the catalytic reformed gasoline.