JP2006022253A - Low-pollution fuel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-pollution fuel by which the discharge of an environmental contaminant can be reduced while keeping the characteristics as a fuel good, and which is excellent in safety and preservation stability. <P>SOLUTION: The low-pollution fuel comprises 50-70 mass% ethanol, 5-15 mass% methyl t-butyl ether, 5-15 mass% diethyl ether and 12-28 mass% dibutyl ether. The low-pollution fuel is preferably set so that the electroconductivity may be within 500-1,000 μS/m. The ethanol is preferably derived from a biomass, and especially preferably obtained by using at least one or more kinds selected from sugarcane, corn and sweet potato as raw materials. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention can significantly reduce emissions of environmental pollutants such as CO ₂ , No _x , and SO _x while maintaining fuel characteristics such as calorific value, output, and driving performance, and is safe and secure. It relates to a low-pollution fuel with excellent stability.

Conventionally, petroleum-based fuels, that is, fossil fuels, have been mainstream as fuels used for automobiles, various machines and the like for industrial or household use. However, the limit of fossil fuel reserves has begun to appear, and in recent years when global warming has become a problem, the necessity of circulating energy has been pointed out. CO ₂ emissions from the use of gasoline as a fossil fuel for automobiles extends to 8.2% of Japan's CO ₂ emissions, the load on the environment by the use of the automobile fossil fuels is serious. Japan also relies on imports for nearly 98% of fossil fuels, and out of all energy consumed in Japan, about 80% is derived from fossil fuels. For this reason, fossil fuels are an important issue from the viewpoint of securing energy stably. On the other hand, environmental pollutants such as CO ₂ , No _x , and SO _x generated by burning fossil fuels also cause serious environmental problems.

  Under such circumstances, in recent years, ethanol that can be produced at low cost from corn, soybeans, kenaf, natural wood, and other various raw materials or industrial wastes has attracted particular attention as a fuel for automobiles. Ethanol is being introduced and researched around the world as a circulating fuel or raw material. A fuel consisting of ethanol alone is a so-called clean fuel that generates significantly less toxic oxides during combustion than gasoline and has a high octane number. However, since the calorific value and air-fuel ratio are small and the vaporized liquid heat is large compared to gasoline, it is difficult to start in a cold region. In addition, there is a drawback in that a part of a metal that is a component of an automobile is corroded and oxidized. Therefore, when ethanol is used as the fuel, it is the actual situation that an additional device is provided in the engine or a mixed fuel with gasoline is used. As fuel blended with gasoline, for example, E85, E10, etc., in which 10% to 12% ethanol is added to gasoline are put into practical use. However, these fuels with a relatively high gasoline content have an environmental impact. It is difficult to obtain a sufficient effect in terms of reduction of the above.

  In addition, ethanol blended gasoline in which ethanol with a water content of 0.3% or less is mixed with gasoline in an amount of 5 to 85% is officially used as a fuel for automobiles in some countries such as Brazil, the United States and the EU ( For example, E10, E25, E85). However, since the amount of ethanol added is small or it is necessary to modify the engine or install an additional device, the value as a gasoline alternative fuel is low. Moreover, when said ethanol mixed gasoline absorbs a water | moisture content, there exists a fault that there exists a tendency which isolate | separates into gasoline and ethanol.

  As a method for obtaining a fuel mainly composed of ethanol, for example, Patent Document 1 discloses that biomass is collected, pulverized, and slurried by adding water, and the slurry is maintained in a subcritical or supercritical state of water. A method for producing fuel from biomass by decomposing, saccharifying, and fermenting the polysaccharides contained in is proposed. As fermentation methods, ethanol fermentation or methanol fermentation has been proposed.

  Patent Document 2 proposes a fuel containing alcohol as a main component and containing a paraffinic hydrocarbon composed of 5 to 8 carbon atoms. As alcohol, a mixed alcohol composed of ethanol and / or methanol and isopropyl alcohol and isobutanol has been proposed.

  Patent Document 3 proposes a method of obtaining a fatty acid alcohol ester that can be used as a light oil alternative fuel by transesterifying oil and fat with alcohol.

The fuel obtained from Patent Documents 1 to 3 has alcohol as a main component, and can greatly reduce the load on the environment in terms of reducing the discharge amount of environmental pollutants. However, alcohol-based fuels are generally easily oxidized, and when oxidation proceeds, the properties of the fuel are lowered, and there is a concern that the safety may be lowered due to corrosion of the fuel tank. That is, it is difficult for the methods of Patent Documents 1 to 3 to sufficiently ensure safety and storage stability.
JP 2001-262162 A JP 2002-80867 A Japanese Patent Laid-Open No. 2004-156022

  An object of the present invention is to solve the above-mentioned problems and to provide a low-pollution fuel that can reduce the discharge amount of environmental pollutants while maintaining good characteristics as a fuel and that is excellent in safety and storage stability. To do.

  The present invention contains 50 to 70% by mass of ethanol, 5 to 15% by mass of methyl-t-butyl ether, 5 to 15% by mass of diethyl ether, and 12 to 28% by mass of dibutyl ether as essential components. It relates to low-pollution fuels contained.

  The ethanol blended with the low pollution fuel of the present invention is preferably derived from biomass.

  In the low pollution fuel of the present invention, the electric conductivity is preferably set in a range of 500 to 1000 μS / m.

  In the low pollution fuel of the present invention, the oxidation stability is preferably 900 minutes or more.

  The ethanol blended in the low pollution fuel of the present invention is preferably obtained using one or more selected from sugarcane, corn, and sweet potato as raw materials.

  Since the low pollution fuel of the present invention contains ethanol as a main component, it is possible to reduce the discharge amount of environmental pollutants without greatly reducing the calorific value, output, and operation performance as compared with petroleum fuel. Moreover, oxidation stability is good because the electric conductivity is controlled within a predetermined range. As a result, safety and storage stability are ensured, and it can be used as it is in a conventional gasoline vehicle.

  The low pollution fuel of the present invention is 50 to 70% by mass of ethanol, 5 to 15% by mass of methyl-t-butyl ether, 5 to 15% by mass of diethyl ether, 12 to 28% by mass of dibutyl ether, Is contained as an essential component. With the above composition, a fuel with both excellent fuel efficiency and oxidation stability can be obtained, and layer separation at low temperatures is unlikely to occur, so sufficient startability and weather resistance even for long-term storage and winter use Have Of these, a particularly preferred ethanol content of 55 to 65% by mass can be employed, and the particularly preferred content of other components is also 8 to 12% by mass for methyl-t-butyl ether and 8 to 12% by mass for diethyl ether. In dibutyl ether, 15 to 25% by mass can be employed.

  The low pollution fuel of the present invention preferably has an electric conductivity set in the range of 500 to 1000 μS / m. The electrical conductivity greatly affects the oxidation stability of the fuel. When the electrical conductivity is low, there is a tendency that oxidation is difficult to proceed because there are few free ions (decrease in free radicals). Therefore, in the present invention, in order to prevent deterioration due to oxidation of the fuel, it is preferable to reduce the electric conductivity as much as possible. However, if the electric conductivity is 500 μS / m or more, it is necessary to provide a complicated process. Since there are few technical difficulties, it is preferable in terms of production cost and raw material procurement. Also, if it is 1000 μS / m or less, the electric conductivity is sufficiently low, so that the fuel is effectively prevented from oxidative deterioration, good storage stability is maintained, and corrosion of gasoline tanks, containers, etc. may occur. There is little nature. Particularly for aluminum, it has a great anti-corrosion effect. Thereby, although it is a fuel which has ethanol as a main component, it can be used as it is for the conventional automobile for gasoline. In addition, electrical conductivity can be measured by the method based on the American material test standard (ASTM D1125-95).

  The ethanol contained in the present invention is preferably derived from biomass. When ethanol is extracted and purified from biomass, an ethanol-based mixed liquid in which various trace components other than ethanol remain in ethanol is obtained. Examples of such trace components include acetals such as acetal and diethyl acetal, organic acids such as acetone and acetic acid, alcohols such as methanol, N-propanol, I-butanol, and I-amyl, acetaldehyde, and crotonaldehyde. Aldehydes, amides such as ethyl carbamate, ketones such as methyl ethyl ketone, acetyls such as diacetyl formed from the ketones, esters such as ethyl acetate, and the like.

  In the present invention, since the fuel is prepared while the trace component coexists in ethanol, the trace component has an effect of favorably contributing to the properties as a fuel. In particular, when amides coexist in ethanol, the amides act as an antioxidant, so that the oxidation stability of the fuel is improved. In addition, components such as organic acids and aldehydes contribute to improvement of basic performance as a fuel, such as improvement of fuel consumption.

  The amount and type of the trace component vary depending on the type of biomass and the extraction and purification conditions, but the type, extraction and purification conditions of the biomass can be appropriately selected according to the properties and costs of the target fuel. As biomass, for example, when one or more selected from sugarcane, corn, and sweet potato is used as a raw material, it is preferable because the raw material can be obtained at low cost and good fuel consumption, safety, and storage stability can be obtained. That is, ethanol can be prepared from polysaccharides containing C6 sugars such as starch stored in sugarcane, corn, sweet potato, and other plant seeds, starch stored in rhizomes, sucrose contained in sugarcane, and the like. In addition, ethanol used in the present invention can be prepared from pomace (bagasse) that becomes waste after collecting sugar juice that is raw material of sugar from biomass, so that it is possible to effectively use resources. Have advantages.

  Although the method of preparing ethanol used for this invention from biomass is not specifically limited, For example, it can prepare with the following method. First, in the sugar cane pressing process, sugar juice (sugar juice) that is a raw material of sugar and bagasse including squeezed fibers mainly composed of cellulose are separated. When sugar is produced from sugar juice, waste beet sugar (molasses) is obtained as a residue after the sugar crystallization process, and ethanol is produced from molasses through a fermentation process. When not producing sugar, the juice is sent to the fermentation process as it is to produce ethanol.

  When ethanol for gasohol is produced from bagasse, the ethanol is produced through saccharification, fermentation, ethanol separation, and dehydration processes. After separating impurities from bagasse in the pretreatment step, fibrous cellulose is hydrolyzed to glucose in the saccharification step and fermented with yeast in the fermentation step to obtain ethanol. Here, as the hydrolysis reaction in the saccharification step, a biotechnological method using an enzyme and a method using sulfuric acid can be employed.

  Ethanol is obtained as a mixed liquid containing various trace components (hereinafter referred to as “ethanol component”) by the above process. In the present invention, ethanol produced from biomass is preferably mixed with other components in the state of the ethanol component to produce a low pollution fuel.

  Usually, since the ethanol component prepared from biomass by the above method contains about 5% by mass of water, dehydration is further performed. Specific methods of dehydration include, for example, a method of adding and distilling a third component such as cyclohexane, a method of adding and distilling glycol or glycerin, and a ball-like superporous material such as zeolite. For example, a method of adsorbing water to the superporous material using a porous material may be employed.

  The ethanol component prepared from biomass is preferably adjusted to a pH of 7.0 to 9.0, particularly 8.0. In this case, oxidation of the low-pollution fuel is suppressed, and good weather resistance and storage stability are imparted.

  The electrical conductivity of the ethanol component prepared from biomass is preferably 500 μS / m or less, particularly 100 μS / m or less. The electric conductivity in the low pollution fuel of the present invention greatly depends on the electric conductivity of an ethanol component containing ethanol blended as a main component. It is preferable that the electrical conductivity of the ethanol component is 500 μS / m or less because the ethanol component can be produced relatively easily and good storage stability can be imparted to a low pollution fuel.

  The ethanol component used in the present invention may be, for example, so-called anhydrous ethanol having an ethanol concentration of 99.6% by mass or more, but is more preferably hydrous ethanol having a water content of 2 to 3% by mass. In this case, low pollution fuel tends to have good fuel efficiency.

  In the low pollution fuel of the present invention, the oxidation stability is preferably 500 minutes or more, particularly 900 minutes or more. In this case, oxidation of the low-pollution fuel is suppressed, and good storage stability can be maintained. The oxidation stability can be measured with an oxidation stability tester according to JIS K 2287 (oxidation stability test method).

  In addition to ethanol, methyl-t-butyl ether, diethyl ether, and dibutyl ether, the low-emission fuel of the present invention further includes ethers such as isopropyl ether and ethyl t-butyl ether, and alcohols such as t-butanol. For example, those synthesized and purified from natural gas or the like can be used.

  Furthermore, various additives can be blended in the low pollution fuel of the present invention as components other than the alcohols and ethers described above depending on the desired performance. Specifically, aluminum phosphate or its compounds frequently used in automobile fuel systems and engine parts, as an additive for inhibiting corrosion of iron, steel, etc. used conventionally, alkyl phosphate amine salts, aliphatic amines And fatty acid esters. Commercially available additives include, for example, “DC1-11” manufactured by Octel, “Tolad 3222” “Tolad 3224” manufactured by Petrolite, “5403” manufactured by Nalco. Examples thereof include “FE-9730” manufactured by ENDCOR (end core), “MCC5011E” and “MCC5011EW” manufactured by MidContinental. Moreover, 2,6-di-t-butyl-4-methylphenol, N, N-diisopropyl-p-phenylenediamine, etc. as additives for reducing the swelling of rubbers used in vehicles and engine combustion systems, Examples of the additive for improving the oxidation stability of the low pollution fuel include an antioxidant such as butyl toluene hydroxide (BHT). By blending these additives, it is possible to improve performance as a fuel such as air-fuel ratio, distillation properties, reed vapor pressure, etc., as well as improving safety and storage stability, Almost the same calorific value, output, and driving performance are provided.

  The blending amount of the above additive in the present invention depends on the blending ratio of ethanol and ether, the storage temperature of the low pollution fuel, the use temperature, etc. It can be set to not less than mass%, preferably not less than 0.5 mass%, more preferably not less than 3 mass%.

  The moisture content of the low pollution fuel of the present invention is preferably adjusted within the range of 2.0 to 3.0 mass%. If the water content is 2.0% by mass or more, it is not necessary to go through a complicated process, which is advantageous in terms of manufacturing cost. In addition, for example, when mixed with gasoline, there is an advantage that layer separation hardly occurs.

The low pollution fuel of the present invention preferably contains substantially no sulfur content. In this case, there is no danger of a negative impact on the environment by the discharge of SO _x.

  In the present invention, by adjusting the mixing ratio of the ethanol component and the ether component, the vapor pressure of the low pollution fuel at 37.8 ° C. is 30% or more of the vapor pressure of the low pollution fuel at the 30% by volume distillation temperature. It is preferable to set so as to be. In this case, for example, when used in an internal combustion engine for a vehicle, a sufficient amount of flammable gas in the gas phase is secured, and good engine startability is obtained. As a preferable range of the vapor pressure at 37.8 ° C., for example, the range of 35 to 50 kPa can be exemplified. The vapor pressure can be measured by the lead method based on JIS K2258. The distillation temperature can be measured based on JIS K2254.

  The 10 vol% distillation temperature of the low pollution fuel of the present invention is preferably 70 ° C or lower. In this case, there is an advantage that vapor lock hardly occurs during summer use. Moreover, it is preferable that 50 volume% distillation temperature exists in the range of 75-110 degreeC. In this case, for example, it has good engine startability at the time of overtaking acceleration when used for a vehicle, at the time of acceleration on an uphill, at the time of rising at a corner, etc. Moreover, it is preferable that 90 volume% distillation temperature shall be 180 degrees C or less. In this case, there is an advantage that incomplete combustion is prevented and the risk of the engine oil becoming dirty is reduced. Furthermore, it is preferable that a 100 volume% distillation temperature shall be 220 degrees C or less.

  The low pollution fuel of the present invention can be used as it is for a gasoline tank or the like to which conventional gasoline is supplied as fuel, and is preferably used for various industrial or household vehicles, ships, heavy machinery, manufacturing machines, and the like. Can be applied.

  Even if the low pollution fuel of the present invention is used alone, sufficient fuel characteristics can be obtained. However, if necessary, the low pollution fuel of the present invention can be used as long as it does not impair the characteristics of the low pollution fuel of the present invention. A mixture of gasoline and the like may be used.

<Example>
EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these.

(Preparation of low pollution fuel)
After squeezing sugarcane and squeezing the pomace (bagasse) after collecting the sugar juice, alkali treatment, and then using biomass-derived ethanol obtained through saccharification (hydrolysis), fermentation, distillation and dehydration, according to the present invention Produced low pollution fuel. 60 parts by volume (47.49 parts by mass) of biomass-derived hydrous ethanol “HIDROTADO”, 9.0 parts by volume (6.4467 parts by mass) of diethyl ether, and 20.0 parts by volume of dibutyl ether (15.42) Parts by mass), 9.5 parts by volume (7.0823 parts by mass) of methyl-t-butyl ether, and 3.0 parts by volume (2.655 parts by mass) of 30% by mass NH ₃ water. did. Here, the density of HIDROTADO is 0.7915 g / cm ³ , the density of diethyl ether is 0.7163 g / cm ³ , the density of dibutyl ether is 0.771 g / cm ³ , and the density of methyl-t-butyl ether is The density is 0.7455 g / cm ³ , and the density of 30 mass% NH ₃ water is 0.885 g / cm ³ .

  The biomass-derived water-containing ethanol has a water content of 4.4% by mass and an electrical conductivity of about 500 μS / m. Table 1 shows the properties of the low pollution fuel 1. The distillation temperature was measured based on JIS K 2254, and the vapor pressure was measured based on JIS K 2258.

  A known regular gasoline (trade name “Eneos regular” manufactured by Nippon Oil Corporation) was used for the comparative test.

(1) Metal immersion test (Examples 1 to 6)
In accordance with JIS K 2234, the test temperature is 98 ± 2 ° C., the initial pressure is 12 atm, the pressurized gas is helium, and the metal test pieces shown in Table 2 are immersed in the low pollution fuel 1 for 168 hours. The mass change of the test piece and the appearance (visual observation) of the test piece after immersion were evaluated. The results are shown in Table 2.

(Examples 7 to 12)
An immersion test was performed in the same manner as in Examples 1 to 6 except that the immersion time was 720 hours, and the mass change of the test piece before and after immersion and the appearance (visual observation) of the test piece after immersion were evaluated. The results are shown in Table 2.

(Comparative Examples 1-6)
Except for using regular gasoline instead of the low-pollution fuel 1, the immersion test was performed in the same manner as in Examples 1 to 6, and the change in the mass of the test piece before and after immersion and the appearance (visual) of the test piece after immersion evaluated. The results are shown in Table 2.

Note 1: The cast aluminum is JIS H 5202 AC2A-F.
Note 2: The cast iron is JIS G 5501 FC200.
Note 3: The steel is JIS G 3141 SPCC-B.
Note 4: Brass is JIS H 3100 C2680P.
Note 5: The solder is JIS Z 3282 H30A.
Note 6: Copper is JIS H 3100 C1100P.

(2) Rubber immersion test (Examples 13 and 14)
In accordance with JIS K 6258, the rubber samples shown in Table 3 were immersed in the low pollution fuel 1 at 60 ± 1 ° C. for 72 hours. The rubber samples before and after the immersion were subjected to a durometer test based on JIS-K6253 and a tensile test based on JIS-K6251 (test piece: dumbbell shape No. 3), and the deterioration state of the rubber sample due to immersion was evaluated. The results are shown in Table 3.

(Comparative Examples 7 and 8)
An immersion test was performed in the same manner as in Examples 13 and 14 except that regular gasoline was used in place of the low pollution fuel 1, and the deterioration state of the rubber sample due to immersion was evaluated. The results are shown in Table 3.

Note 7: Fluoro rubber is manufactured by Togawa Rubber Co., Ltd.
Note 8: Nitrile rubber is manufactured by Togawa Rubber Co., Ltd.

(3) O-ring immersion test (Examples 15 to 17)
The gasoline injection nozzle O-ring shown in Table 4 was immersed in the low pollution fuel 1 at 60 ± 1 ° C. for 72 hours, and the changes in hardness, mass, and volume of the O-ring before and after immersion were evaluated. The results are shown in Table 4.

(Comparative Examples 9-11)
An immersion test was conducted in the same manner as in Examples 15 to 17 except that regular gasoline was used in place of the low pollution fuel 1, and changes in hardness, mass, and volume of the O-ring before and after immersion were evaluated. The results are shown in Table 4.

Note 9: RB-TAT is a trade name “O ring for measuring nozzle” manufactured by Tatsuno Mechatronics.
Note 10: RB-TMC is a trade name “O-ring for measuring nozzle” manufactured by Tominaga Corporation.
Note 11: RB-TOK is a trade name “O-ring for measuring nozzle” manufactured by Tokiko Techno Co., Ltd.

(4) Exhaust gas generation test (Example 18)
After squeezing sugarcane and squeezing the pomace (bagasse) after collecting the sugar juice, alkali treatment, and then using biomass-derived ethanol obtained through saccharification (hydrolysis), fermentation, distillation and dehydration, according to the present invention Produced low pollution fuel. As biomass-derived ethanol, 60 parts by volume (47.49 parts by mass) of HIDROTADO (idlatard), 10 parts by volume (7.613 parts by mass) of diethyl ether, and 20.0 parts by volume (15.42 parts by mass) of dibutyl ether Then, 10 parts by volume (7.455 parts by mass) of methyl-t-butyl ether was mixed. Here, the density of HIDROTADO is 0.7915 g / cm ³ , the density of diethyl ether is 0.7163 g / cm ³ , the density of dibutyl ether is 0.771 g / cm ³ , and the density of methyl-t-butyl ether is The density is 0.7455 g / cm ³ .
The density of the low pollution fuel 2 was 0.7844 g / cm ³ and the octane number (research method) was 98 or more. The 10 vol% distillation temperature was 57 ° C or lower, the 50 vol% distillation temperature was 63 ° C or lower, the 90 vol% distillation temperature was 75 ° C or lower, and the thousand points were 160 ° C or lower.

  When aluminum, cast iron, solder, and copper test pieces were each immersed in the low pollution fuel 2 at 98 ° C. and 12 atmospheres for 720 hours, no corrosion was observed in any of the test pieces. Further, when the low pollution fuel 2 was stored in the open air at room temperature for 360 days, abnormalities such as oxidation, layer separation, and composition change were not recognized. Furthermore, the layer separation temperature of the low pollution fuel 2 is −29.5 ° C., and it has been found that it can sufficiently withstand use in winter. The allowable maximum water content at 20 ° C. of the low pollution fuel 2 was 2.52% by mass.

For the low pollution fuel 2, the emission amount of CO value, HC value and No _x value was measured. These measurements were performed using “MEXA-7200D” manufactured by Horiba, Ltd. The NO _x emission amount was measured by the 10 mode method. The results are shown in Table 5.

(Comparative Example 12)
Emissions of CO value, HC value, and No _x value were measured in the same manner as in Example 18 except that a known regular gasoline (trade name “Eneos regular” manufactured by Nippon Oil Corporation) was used. The results are shown in Table 5.

(5) Fuel characteristic test (Examples 19 to 29, Comparative Example 13)
Biomass-derived hydrous ethanol “HIDROTADO”, methyl-t-butyl ether (MTBE), diethyl ether (DEE), dibutyl ether (DBE), isopropyl ether (IPE), t-butyl alcohol (TBA), and additive X The volume parts shown in Table 6 (mass parts in parentheses) are mixed, and the fuel consumption, maximum horsepower, and engine speed when the actual vehicle is running at 80 km / h are measured, respectively, and known regular gasoline (Shin Nippon Oil Co., Ltd.) The product name “Eneos regular”) was used, and the relative value was evaluated with the value taken as 100%. The results are shown in Table 6. Here, the density of HIDROTADO is 0.7915 g / cm ³ , the density of diethyl ether is 0.7163 g / cm ³ , the density of dibutyl ether is 0.771 g / cm ³ , and the density of methyl-t-butyl ether is The density is 0.7455 g / cm ³ , the density of isopropyl ether is 0.722 g / cm ³ , the density of t-butyl alcohol is 0.7558 g / cm ³ , and the density of additive X is 1.0215 g / cm ³ . ³ .

  From the results of Examples 1-6 and Comparative Examples 1-6, under the immersion conditions of 98 ± 2 ° C. and 168 hours, the low-pollution fuel of the present invention is alcohol-based, but is substantially different from regular gasoline in metal corrosiveness. From this, it can be seen that the low pollution fuel of the present invention has good corrosion resistance. Moreover, from the results of Examples 7 to 12, no corrosion is seen in aluminum castings, cast iron, and steel even under immersion conditions of 98 ± 2 ° C. and 720 hours. For example, when used as a fuel for automobiles Corrosion resistance can be sufficiently secured.

  From the results of Examples 13 and 14 and Comparative Examples 7 and 8, the low-pollution fuel of the present invention tends to be greatly deformed as compared with conventional gasoline with respect to fluororubber, but the low-pollution fuel of the present invention with respect to nitrile rubber. Since deformation is smaller than that of conventional gasoline, it can be seen that the low pollution fuel of the present invention has an effect of suppressing deformation of nitrile rubber.

  From the results of Examples 15 to 17 and Comparative Examples 9 to 11, the deformation of the O-ring occurs in both the low pollution fuel of the present invention and the conventional gasoline, but the degree of deformation as a whole is the low pollution of the present invention. You can see that the fuel is smaller.

From the results of Example 18 and Comparative Example 12, since the CO value, HC value, and NO _x value of Example 18 are significantly lower than those of Comparative Example 12, the low pollution fuel of the present invention reduces the emission amount of environmental pollutants. It can be seen that the effect is significantly reduced.

  From the results of Examples 19 to 29 and Comparative Example 13, although the low pollution fuel of the present invention is a fuel mainly composed of ethanol, all of the fuel consumption, the maximum horsepower, and the rotational speed are remarkably reduced as compared with conventional gasoline. It can be seen that it has good fuel characteristics.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  According to the present invention, it is possible to provide a low-pollution fuel that can reduce the discharge amount of environmental pollutants while maintaining good characteristics as a fuel, and that is excellent in safety and storage stability. The low-pollution fuel of the present invention is suitable as an alternative fuel for petroleum because it can be used as it is in conventional gasoline automobiles, etc., with ethanol as the main component.

Claims (5)

  A low-pollution fuel containing 50 to 70% by weight of ethanol, 5 to 15% by weight of methyl-t-butyl ether, 5 to 15% by weight of diethyl ether, and 12 to 28% by weight of dibutyl ether.   The low-pollution fuel according to claim 1, wherein the ethanol is derived from biomass.   The low-pollution fuel according to claim 1, wherein the electric conductivity is set within a range of 500 to 1000 μS / m.   The low pollution fuel according to claim 1, wherein the oxidation stability is 900 minutes or more.   The low-pollution fuel according to claim 1, wherein the ethanol is obtained using one or more selected from sugarcane, corn, and sweet potato as a raw material.