JP2005060572A - Gasoline - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide gasoline with which the exhaust gas cleanup capability of vehicles can be maintained for a long time. <P>SOLUTION: This gasoline contains (1) not more than 2 ppm by mass of manganese, (2) not more than 2 ppm by mass of iron, (3) not more than 2 ppm by mass of sodium, (4) not more than 2 ppm by mass of potassium, and (5) not more than 2 ppm by mass of phosphorus. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to gasoline as a fuel for automobiles, and more particularly to gasoline capable of maintaining exhaust gas purification performance over a long period of time.

  Due to the recent increase in awareness of environmental issues, it has been required to reduce automobile exhaust gas, and the relationship between fuel properties and automobile exhaust gas has been studied. As a result, advanced exhaust gas purification systems are being developed and adopted on the automobile side. Moreover, in the examination on the fuel side, it is known that a heavy fuel or a fuel having a high sulfur content adversely affects the exhaust gas (see, for example, Non-Patent Document 1 and Non-Patent Document 2). However, in order to adapt to an advanced exhaust gas purification system on the automobile side, more severe fuel properties are required, and in particular, a fuel that can maintain the exhaust gas purification performance over a long period of time is eagerly desired.

Kameoka et al., “Automotive Technology Society Academic Lecture Preprints”, Automotive Technology Association, 1998, No. 88-98, 9838985 Gasoline Vehicle Working Group JCAP Results Report (2) Effects of Automobile Technology and Fuel Properties on Gasoline Vehicles on Emissions, “JCAP Results Presentation (Tokyo International Forum)”, Oil Industry Revitalization Center Promotion Office, 1998 September 30

  The present invention provides gasoline that can maintain the exhaust gas purification performance of a vehicle over a long period of time compared to conventional gasoline in order to reduce the environmental load.

As a result of intensive studies on the above problems, the present inventors have found that the exhaust gas purification performance can be maintained over a long period of time when gasoline having a specific metal content of a certain amount or less is used. Has been completed.
That is, the present invention has (1) a manganese content of 2 mass ppm or less, (2) an iron content of 2 mass ppm or less, (3) a sodium content of 2 mass ppm or less, (4) potassium The present invention relates to a gasoline having a content of 2 mass ppm or less and (5) a phosphorus content of 2 mass ppm or less.
The gasoline of the present invention preferably has a sulfur content of 10 mass ppm or less.

Hereinafter, the present invention will be described in detail.
The gasoline of the present invention has a manganese content of 2 mass ppm or less, an iron content of 2 mass ppm or less, a sodium content of 2 mass ppm or less, a potassium content of 2 mass ppm or less, and a phosphorus content. Is required to be 2 ppm by mass or less. If the contents of manganese, iron, sodium, potassium, and phosphorus exceed the above values, the efficiency of the exhaust gas purification system will increase due to an increase in the amount accumulated on the exhaust gas purification catalyst, deterioration of the catalyst carrier, deterioration of the air-fuel ratio sensor, etc. Is not preferable. For this reason, the manganese content is preferably 1 mass ppm or less, the iron content is preferably 1 mass ppm or less, the sodium content is preferably 1 mass ppm or less, and the potassium content is 1 mass ppm or less. Preferably, the phosphorus content is preferably 1 mass ppm or less, and more preferably 0.2 mass ppm or less.
The manganese, iron, and sodium contents here are “combustion ashing-inductively coupled plasma emission method”, the potassium content is “combustion ashing-atomic absorption method”, and the phosphorus content is ASTM D3231 “Standard”. It is a value measured by “Test Method for Phosphorus in Gasoline”.

The measurement methods of “combustion ashing-inductively coupled plasma emission method” and “combustion ashing-atomic absorption method” are performed as follows.
(1) Collect 20 g of a sample in a platinum dish.
(2) In order to suppress volatilization of the component elements, 0.4 g of powdered sulfur is added and evaporated to dryness at 150 ° C. for 1 hour on a sand bath to remove volatile components.
(3) Burn the residue.
(4) Ashing in an electric furnace at 500 ° C. for 2 to 3 hours.
(5) Dissolve in 2 to 3 mL of concentrated sulfuric acid and make a constant volume of 20 mL.
(6) Manganese, iron, sodium content is inductively coupled plasma emission spectrometer (ICPS-8000, manufactured by Shimadzu Corporation), potassium content is atomic absorption photometer (manufactured by Hitachi, Ltd., Z6100) ) To analyze.

The sulfur content of the gasoline of the present invention is not particularly limited, but is preferably 10 mass ppm or less, more preferably 8 mass ppm or less. If the sulfur content exceeds 10 ppm by mass, the performance of the exhaust gas treatment catalyst may be adversely affected, the concentration of NOx, CO, and HC in the exhaust gas may increase, and the amount of benzene emitted also increases. there is a possibility.
The sulfur content here means a value (mass ppm) measured by JIS K 2541 “Crude oil and petroleum products—Sulfur content test method”.

The distillation property of the gasoline of the present invention is not particularly limited, but is preferably as follows. The distillation property as used herein means a distillation property measured by JIS K 2254 “Petroleum products—Distillation test method”.
First distillation point (IBP): 20-37 ° C
10 volume% distillation temperature (T10): 35-70 degreeC
30% by volume distillation temperature (T30): 55 to 77 ° C
50 volume% distillation temperature (T50): 75-105 degreeC
70% by volume distillation temperature (T70): 135 ° C. or less 90% by volume distillation temperature (T90): 175 ° C. or less Distillation end point (EP): 215 ° C. or less

IBP is preferably 20 ° C. or higher, more preferably 23 ° C. or higher. When IBP is less than 20 ° C., hydrocarbons in the exhaust gas may increase. On the other hand, IBP is preferably 37 ° C. or lower, more preferably 35 ° C. or lower. When IBP exceeds 37 ° C., low-temperature drivability may be reduced.
T10 is preferably 35 ° C. or higher, more preferably 40 ° C. or higher. When T10 is less than 35 ° C., hydrocarbons in the exhaust gas may increase, and high temperature operability may decrease due to vapor lock. On the other hand, T10 is preferably 70 ° C. or lower, more preferably 60 ° C. or lower. When T10 exceeds 70 ° C, the low temperature startability may be reduced.

T30 is preferably 55 ° C. or higher, more preferably 60 ° C. or higher. When T30 is less than 55 ° C., fuel consumption may be reduced. On the other hand, T30 is preferably 77 ° C or lower, more preferably 75 ° C or lower, and further preferably 70 ° C or lower. When T30 exceeds 77 ° C, the medium / low temperature drivability may be lowered.
T50 is preferably 75 ° C. or higher, more preferably 80 ° C. or higher. When T50 is less than 75 ° C., fuel consumption may be reduced. On the other hand, T50 is preferably 105 ° C. or lower, more preferably 100 ° C. or lower, and further preferably 95 ° C. or lower. When T50 exceeds 105 ° C., the normal temperature drivability may be deteriorated.

T70 is preferably 135 ° C. or lower, more preferably 130 ° C. or lower. When T70 exceeds 135 ° C., the medium / low temperature operability during cold operation may decrease, and there may be an increase in hydrocarbons in exhaust gas, an increase in intake valve deposits, and an increase in combustion chamber deposits. .
T90 is preferably 175 from the viewpoint of preventing phenomena such as deterioration of low temperature and normal temperature drivability during cold operation, increase in dilution of engine oil with gasoline, increase in hydrocarbon exhaust gas, deterioration of engine oil and generation of sludge. ° C or lower, more preferably 170 ° C or lower, and still more preferably 165 ° C or lower.
EP is preferably 215 ° C. or lower, more preferably 200 ° C. or lower, and still more preferably 195 ° C. or lower. If EP exceeds 215 ° C., intake valve deposits and combustion chamber deposits may increase, and spark plug smoldering may occur.
Here, IBP, T10, T30, T50, T70, T90, and EP mean values (° C.) measured by JIS K 2254 “Petroleum products—distillation test method”.

The density at 15 ° C. of the gasoline of the present invention is not particularly limited, but is preferably 0.710 to 0.783 g / cm ³ . If the density of the gasoline composition is less than 0.710 g / cm ³ , the fuel efficiency may be deteriorated. On the other hand, if it exceeds 0.783 g / cm ³ , the acceleration may be deteriorated and the plug may be smoldered. There is. For this reason, 0.735 g / cm ³ or more is more preferable, 0.770 g / cm ³ or less is more preferable, and 0.760 g / cm ³ or less is more preferable.
The density at 15 ° C. here means a value (g / cm ³ ) measured according to JIS K 2249 “Density test method and density / mass / capacity conversion table for crude oil and petroleum products”.

The lead vapor pressure (RVP) of the gasoline of the present invention is not particularly limited, but is preferably adjusted according to the season and region in which the gasoline composition is used. More specifically, in the summer (May to September), it is preferably 44 to 65 kPa, more preferably 50 to 65 kPa, and most preferably 55 to 65 kPa in order to prevent drivability due to vapor lock or the like. It is desirable to adjust. On the other hand, in winter (October to April), it is preferable to adjust to 44 to 93, more preferably 65 to 93 kPa, still more preferably 70 to 93 kPa, and most preferably 70 to 90 kPa.
The vapor pressure (RVP) here refers to a value (kPa) measured by JIS K 2258 “Crude oil and fuel oil vapor pressure test method (Lead method)”.

The gasoline research octane number of the present invention is preferably 89.0 or more, more preferably 90.0 or more from the viewpoint of preventing knocking and improving drivability. Further, when the gasoline of the present invention is used for a premium gasoline specification vehicle, in order to maximize the performance of the automobile, it is preferably 96.0 or more, more preferably 98.0 or more, and most preferably It is 100.0 or more. Further, from the viewpoint of preventing deterioration of anti-knocking performance at high speed, the motor method octane number is preferably 80 or more.
The research method octane number and the motor method octane number here mean the research method octane number and the motor method octane number measured by JIS K 2280 “Testing method for octane number and cetane number”.

The aromatic content in the gasoline of the present invention is not particularly limited, but is preferably 20 to 45% by volume, more preferably 25% by volume or more and 42% by volume or less. If the aromatic content exceeds 45% by volume, intake valve deposits and combustion chamber deposits may increase, and spark plug smoldering may occur. In addition, the concentration of benzene in the exhaust gas may increase. On the other hand, if the aromatic content is less than 20% by volume, the fuel efficiency may deteriorate.
Furthermore, the benzene content in the gasoline of the present invention is preferably 1% by volume or less. If the benzene content exceeds 1% by volume, the concentration of benzene in the exhaust gas may increase.

The olefin content in the gasoline of the present invention is not particularly limited, but is preferably 30% by volume or less, and more preferably 25% by volume or less. When the olefin content exceeds 30% by volume, there is a possibility that the oxidation stability of gasoline is deteriorated and the intake valve deposit is increased.
The aromatic content, the benzene content, and the olefin content mentioned here are the aromatic content (volume%) and the benzene content (volume%) in gasoline as measured by JIS K 2536 “Petroleum products-component test method”. ) And olefin content (volume%).

The amount of kerosene mixed in the gasoline of the present invention is preferably 4% by volume or less. If the amount of kerosene mixed exceeds 4% by volume, the startability of the engine may deteriorate.
Here, the amount of kerosene mixed is determined by the content of normal paraffin hydrocarbons having 13 and 14 carbon atoms on the basis of the total amount of gasoline. It means 4% by volume or less.

  The lead content of the gasoline of the present invention is preferably not detected from the viewpoint of protecting the exhaust gas purification system, and preferably contains substantially no alkyl lead compound such as tetraethyl lead. Even if a very small amount of lead compound is contained, the content is not more than the lower limit value (0.001 g / L or less) applicable to JIS K 2255 “Testing method for lead content in gasoline”.

The oxidation stability of the gasoline of the present invention is not particularly limited, but is preferably 240 minutes or more, more preferably 480 minutes or more, and further preferably 1440 minutes or more. If the oxidative stability is less than 240 minutes, gums can form during storage.
The oxidation stability here means a value (minutes) measured by JIS K 2287 “Gasoline oxidation stability test method (induction period method)”.

The amount of unwashed actual gum of the gasoline of the present invention is not particularly limited, but is preferably 20 mg / 100 mL or less, and more preferably 18 mg / 100 mL or less. Moreover, it is preferable that it is 3 mg / 100 mL or less, and, as for a washing | cleaning real gum amount, it is more preferable that it is 1 mg / 100 mL or less. When the unwashed actual gum amount and the washed actual gum amount exceed the above values, there is a concern that precipitates are generated in the fuel introduction system or the suction valve is stuck.
The unwashed actual gum amount and the washed actual gum amount here mean values (mg / 100 mL) measured according to JIS K 2261 “Petroleum products—Automotive gasoline and aviation fuel oil—Real gum test method—Jet evaporation method”. To do.

  The gasoline of the present invention preferably has a copper plate corrosion (50 ° C., 3 h) of 1 or less, more preferably 1a. If the copper plate corrosion exceeds 1, the fuel system conduit may corrode. The copper plate corrosion here means a value measured according to JIS K 2513 “Petroleum products—copper plate corrosion test method” (test temperature 50 ° C., test time 3 hours).

The gasoline of the present invention can be prepared by blending one or two or more kinds of gasoline base materials and, if desired, adding a cleaning dispersant and other additives described later.
The gasoline base material used for the gasoline of the present invention can be produced by any conventionally known method. Specifically, light naphtha obtained by atmospheric distillation of crude oil, heavy naphtha, desulfurized heavy naphtha obtained by desulfurizing heavy naphtha, catalytic cracking gasoline obtained by catalytic cracking, hydrocracking process Hydrocracked gasoline obtained in the above, reformed gasoline obtained by catalytic reforming method, raffinate which is a residue extracted from aromatics from reformed gasoline, polymerized gasoline obtained by polymerization of olefin, hydrocarbons such as isobutane Alkylate obtained by adding (alkylating) a lower olefin to the product, isomerized gasoline obtained by converting light naphtha to isoparaffin using an isomerizer, denormalized paraffin oil, butane, aromatic hydrocarbon compound, propylene After the dimerization and subsequent hydrogenation of the paraffin fraction, natural gas, etc., which are decomposed into carbon monoxide and hydrogen, F T (Fischer-Tropsch) a substrate of the light fraction and the like of the resulting synthetic GTL (Gas to Liquids) can be prepared by mixing one or two or more.
A typical gasoline formulation is described below. However, the blending amount of each gasoline base material is adjusted so that the finally obtained gasoline satisfies the regulations as the gasoline of the present invention.
(1) Reformed gasoline: 0 to 70% by volume
(2) Cracked gasoline: 0 to 50% by volume
(3) Alkylate: 0 to 40% by volume
(4) Isomerized gasoline: 0-30% by volume
(5) Light naphtha: 0 to 10% by volume
(6) Destilled heavy naphtha: 0 to 20% by volume
(7) Butane: 0 to 10% by volume

The gasoline of the present invention may contain an oxygen-containing compound.
Examples of the oxygen-containing compound include alcohols having 2 to 4 carbon atoms and ethers having 4 to 8 carbon atoms. Specific examples of oxygen-containing compounds include ethanol, methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), tert-amyl methyl ether (TAME), and tert-amyl ethyl ether. it can. Of these, ethanol, MTBE, and ETBE are preferable. In particular, in consideration of environmental effects such as carbon dioxide emission during production, ethanol derived from biomass and ETBE produced using biomass-derived ethanol as a raw material can be preferably used. Methanol is not detected when tested in accordance with JIS K 2536 “Petroleum products-Ingredient test method” (0.5% by volume) because methanol may have a high aldehyde concentration in the exhaust gas and is corrosive. It is preferable that These compounds are originally contained in the raw material, and their content is determined in the process of preparing gasoline having the desired properties by mixing one or more gasoline base materials.
The upper limit of the oxygen content in the gasoline is preferably 2.7 mass%, more preferably 2.0 mass%, and even more preferably 1.5 mass%. If it exceeds 2.7% by mass, NOx in the exhaust gas may increase.

  The gasoline of the present invention preferably contains a cleaning dispersant if the metal content of the gasoline after the addition is within the above-mentioned range. As the cleaning dispersant, compounds known as gasoline cleaning dispersants such as succinimide, polyalkylamine, and polyetheramine can be used. Among these, those having no residue when pyrolysis is performed at 300 ° C. in air are desirable. Preferably, polyisobutenylamine and / or polyetheramine is used. Intake valve deposits can be prevented by the addition of a cleaning dispersant. The content of the cleaning dispersant is preferably 25 to 1000 mg / L based on the total amount of gasoline, more preferably 50 to 500 mg / L, and most preferably 100 to 300 mg / L from the viewpoint of preventing intake valve deposits.

Specific examples of other fuel oil additives that can be added to the gasoline of the present invention include N, N′-diisopropyl-p-phenylenediamine, N, N′-diisobutyl-p-phenylenediamine, 2, Antioxidants such as 6-di-t-butyl-4-methylphenol and hindered phenols, and metal deactivators such as amine carbonyl condensation compounds such as N, N′-disalicylidene-1,2-diaminopropane Surface ignition inhibitors such as organic phosphorus compounds, anti-freezing agents such as polyhydric alcohols or ethers thereof, alkali metal or alkaline earth metal salts of organic acids, auxiliary alcohols such as higher alcohol sulfates, anionic surface activity Agent, cationic surfactant, antistatic agent such as amphoteric surfactant, colorant such as azo dye, organic carboxylic acid or the like Derivatives, rust preventives such as alkenyl succinates, draining agents such as sorbitan esters, discriminating agents such as kirizanine and coumarin, odorants such as natural essential oil synthetic fragrances, higher carboxylic acid monoglycerides and higher carboxylic acid amides Examples thereof include friction modifiers such as a mixture of compounds.
One or more of these additives can be added as long as the gasoline metal content after addition is within the above-mentioned range, and the total amount added is 0.1% by mass based on the total amount of gasoline. The following is preferable.

  The gasoline of the present invention can maintain the exhaust gas purification performance of the vehicle over a long period of time.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[Examples 1-3 and Comparative Examples 1-4]
Prepare gasoline of Example 1 using base materials such as cracked gasoline, reformed gasoline, straight-run light naphtha, butane, alkylate, etc., and blend it with ethanol and ethyl tertiary butyl ether (ETBE). The gasoline of Examples 2 and 3 was adjusted. On the other hand, Comparative Examples 1 to 4 are selected from the octane number improver, the surface ignition preventive agent, the auxiliary burner, the ignitability improver, the scavenger, the valve seat wear preventive agent, the rust preventive agent, and the carburetor detergent, based on Example 1. The fuel oil additive is diluted with an aromatic solvent and added to adjust the metal content, and 2-methylthiophene, benzo [b] thiophene and ditertiary butyl sulfide are added at a molar ratio of 1: 3: 1. And manufactured by adjusting the sulfur content.

(Property measurement)
The properties of gasoline in the examples and comparative examples were measured by the following method.
The density refers to a density measured according to JIS K 2249 “Determination method of density of crude oil and petroleum products and density / mass / capacity conversion table”.
Distillation properties (IBP, T10, T50, T90, EP) are all values measured by JIS K 2254 “Petroleum products—Distillation test method”.
Vapor pressure refers to the lead vapor pressure (RVP) measured by JIS K 2258 “Crude oil and fuel oil vapor pressure test method (Lead method)”.
The contents of manganese, iron and sodium refer to values measured by the above-mentioned “combustion ashing-inductively coupled plasma emission method”.
The potassium content refers to a value measured by the above-mentioned “combustion ashing-atomic absorption method”.
The phosphorus content refers to the value measured by ASTM D3231 “Standard Test Method for Phosphorus in Gasoline”.
The sulfur content refers to the mass content of sulfur based on the total amount of gasoline measured by JIS K2541 “Sulfur content test method”.
Ethanol and ETBE indicate blending amounts of ethanol and ethyl tertiary butyl ether.
The aromatic content, benzene content, and olefin content refer to the aromatic content, benzene content, and olefin content in gasoline as measured by JIS K 2536 “Petroleum products-component test method”.
The lead content refers to the lead content measured by JIS K 2255 “Test method for lead content in gasoline”.
The oxidation stability refers to a value measured by JIS K 2287 “Gasoline oxidation stability test method (induction period method)”.
The unwashed actual gum amount and the washed actual gum amount refer to values measured by JIS K 2261 “Petroleum products—Automotive gasoline and aviation fuel oil—Real gum test method—Jet evaporation method”.

(Test method)
(1) Engine specifications Number of cylinders: Inline 4 cylinders Displacement: 1496cc
Injection system: Multi-point system Mission: Automatic transmission Exhaust gas purification system: Three-way catalyst, air-fuel ratio feedback control Applicable exhaust gas regulations: 2000 regulations

(2) Exhaust gas measurement Using the test vehicle with the above specifications, the vehicle was run for 30,000 km under the long-distance driving conditions specified by the Ministry of Land, Infrastructure, Transport and Tourism, and then the gasoline vehicle 10.15 mode emissions from the Ministry of Land, Infrastructure and Transport In accordance with the technical standards for gas measurement, carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NOx) contained in the exhaust gas were measured. Prior to each long-distance running, the spark plug, exhaust gas purification system (AF sensor, exhaust gas purification catalyst), engine oil, etc. were replaced with new ones.
In addition, CO, HC, and NOx of each gasoline were compared in relative values with the amount of each gas discharged in Example 1 being 100.

  The test results are shown in Table 2. From the test results of Table 2, when gasoline of the present invention (Examples 1 to 3) is used, the CO, HC, and NOx emissions after traveling 30,000 km are higher than the fuels of Comparative Examples 1 to 4. It can be seen that the performance of the exhaust gas purification system is maintained little.

Claims (2)

  (1) Manganese content is 2 mass ppm or less, (2) Iron content is 2 mass ppm or less, (3) Sodium content is 2 mass ppm or less, (4) Potassium content is 2 mass ppm And (5) a gasoline having a phosphorus content of 2 mass ppm or less. The gasoline according to claim 1, wherein the sulfur content is 10 mass ppm or less.