BR112021001413A2 - use of specific volatile fatty esters in gasoline engines to reduce emissions - Google Patents

Abstract

"USE OF SPECIFIC VOLATILE FATTY ESTERS IN PETROL ENGINES TO REDUCE EMISSIONS”. The invention relates to the use of volatile fatty acid esters, where such esters have a number of carbon atoms between 4 and 8, in a fuel for a gasoline engine, in order to reduce emissions of nitrogen oxides, hydrocarbons unburned and particles from gasoline engines.

Description

"USE OF SPECIFIC VOLATILE FATTY ESTERS IN GASOLINE ENGINES TO REDUCE EMISSIONS"

[0001] The present invention relates to improving the quality of gasoline and, in particular, to reducing emissions of nitrogen oxides, unburned hydrocarbons and particles from gasoline engines.

[0002] Today, gasoline engines are preferred over diesel engines because they emit less harmful substances. They are intended to be used in a much larger proportion. However, they emit nitrogen oxides, unburned hydrocarbons and particulates, which are hazardous to the environment and human and animal health.

[0003] Currently, no satisfactory solution has been proposed to reduce all these emissions from gasoline engines.

[0004] The purpose of the invention is to find a product that can be used on an industrial scale and is able to reduce emissions of nitrogen oxides, unburned hydrocarbons and particles from gasoline engines.

[0005] To fulfill said objective, the present invention proposes the use of specific esters.

[0006] Esters have already been used in fossil fuels. In particular, esters of vegetable oils or animal fats were mixed with diesel. These esters are called "long" esters (16 to 20 carbon atoms per molecule) or "medium" esters (8 to 16 carbon atoms per molecule).

[0007] However, said esters do not allow to achieve the objective of the invention, since they cannot be mixed with gasoline due to an insufficient volatility. Furthermore, no esters have been used so far in blends with gasoline to significantly reduce emissions.

[0008] However, according to the invention, the use of one or more "short" esters of volatile fatty acids that comprise a number of carbon atoms per molecule between 4 and 8, in gasoline, surprisingly makes it possible to reduce emissions of nitrogen oxides, unburned hydrocarbons and gasoline engine particulates. Furthermore, the use according to the invention advantageously makes it possible to increase the octane number of the gasoline simultaneously.

[0009] Other features and advantages will appear from the detailed description of the invention below.

DEFINITIONS

[00010] Within the meaning of the invention, "volatile fatty acid" means a monocarboxylic fatty acid with an aliphatic chain of one to six carbon atoms (formic, acetic, propionic, butyric, valeric and caproic acids) or one of their isomers .

[00011] Within the meaning of the invention, "fuel" or "gasoline engine fuel" means a fuel that can operate a gasoline engine, with or without specific engine adjustment, preferably an engine comprising at least gasoline and optionally other components.

[00012] Within the meaning of the invention, "short volatile fatty acid ester" or "short ester" or "short ester of volatile fatty acids" means an ester formed by the reaction of a volatile fatty acid with an alcohol so that the ester comprises a number of carbon atoms between 4 and 8.

[00013] Within the meaning of the invention, "unburned hydrocarbons" means components comprising exclusively carbon and hydrogen atoms, emitted by an engine. Unburned hydrocarbons comprise CH4 methane and the other unburned hydrocarbons, which are also called "non-methane hydrocarbons".

[00014] Within the meaning of the invention, "gasoline octane index" generally means either the octane index RON or the octane index MON.

[00015] Within the meaning of the invention, "research octane index" of gasoline or "RON number" means a number measured according to method NF EN ISO 5164: 2005.

[00016] Within the meaning of the invention, gasoline "engine octane rating" or "MON number" means a number measured in accordance with method NF EN ISO 5163: 2005.

[00017] Within the meaning of the invention, "incorporation of a compound at a rate of x% by volume into the fuel" (in particular "incorporation of esters at a rate of x% by volume into the fuel") means the formation, by any suitable medium, of a mixture, adding a volume of x% of the compound (eg esters) and a volume of 1 to x% of gasoline, and possible other additives present in the fuel. The fuel is thus made up of x% of the compound and 1 to x% of gasoline and possible other additives.

[00018] Within the meaning of the invention, "nitrogen oxides" means compounds comprising only oxygen and nitrogen atoms, the most common in engine emissions being nitrogen monoxide NO and nitrogen dioxide NO2.

[00019] "Carbon number" of an ester or alkane means the number of carbon atoms in an ester or alkane molecule.

[00020] Within the meaning of the invention, "use of a compound at a rate of x% by volume of fuel" (in particular "use of esters at a rate of x% by volume of fuel") means the use, in a gasoline engine, from a fuel formed by the compound (for example, one or more esters), gasoline and possible other additives, obtained by incorporating the compound at a rate of x% by volume in the fuel. The fuel is thus formed by x% of the compound and from 1 to x% of the gasoline and possible other additives.

DETAILED DESCRIPTION OF THE INVENTION

[00021] The invention therefore relates to the use of at least one volatile fatty acid ester, wherein said ester comprises a number of carbons between 4 and 8, in a gasoline engine fuel, in order to reduce emissions of nitrogen oxide and unburned hydrocarbons, and preferably also reduce particulates from gasoline engines.

[00022] Preferably, volatile fatty acid ester(s) comprising(s) a number of carbons between 4 and 8 are used, at a rate of at least 15% by volume of fuel formed by the ester(s), gasoline and possible other constituents, and even more preferably at a rate of at least 20%, preferably at a rate of at least 30% and, according to a particularly suitable embodiment, at a rate of at least 50%. These reasons enable particularly effective results to be obtained in terms of reducing emissions of nitrogen oxides, unburned hydrocarbons and particulate matter from gasoline engines.

[00023] The short ester(s) of volatile fatty acids used according to the invention can be selected from the following esters: ethyl acetate, ethyl propionate , ethyl butyrate, ethyl valerate, ethyl hexanoate, propyl acetate, propyl propionate, propyl butyrate, propyl valerate, butyl acetate, butyl propionate, butyl butyrate and mixtures thereof.

[00024] The ester(s) used according to the invention is/are preferably obtained, totally or partially, from biomass (volatile fatty acids of biomass origin and/or alcohols from origin of biomass) in accordance with any suitable method. They can be obtained, in particular, totally or partially, and preferably entirely, by biomass fermentation (anaerobic fermentation for volatile fatty acids and alcoholic or aceto-butanol fermentation for alcohols), i.e. by esterification of volatile fatty acids of biomass source by alcohols of biomass source. Volatile fatty acids can also be obtained from carbon dioxide or carbon monoxide in a microbial fuel cell. Thus, volatile fatty acid esters comprising a carbon number between 4 and 8 can be obtained entirely or in part by esterification of volatile fatty acids of biomass origin, by alcohols of biomass origin, or by esterification of volatile fatty acids produced from carbon dioxide or carbon monoxide in a microbial fuel cell, by alcohols (alcohols can be of biomass or non-biomass origin).

[00025] Volatile fatty acid esters comprising a number of carbon atoms between 4 and 8, in a fuel for a gasoline engine, enable in particular and can be used to:

[00026] - reduce the emission of nitrogen oxides by gasoline engines by at least 20% of the rate of incorporation of the ester into the fuel, or, for example, a reduction from at least 10% to 50% of the esters incorporated into the fuel ( the emission of nitrogen oxides can, in particular, be measured according to a method that meets the requirements of the European regulation Euro 6, ie regulation 459/2012 of 29 May 2012); and/or

[00027] - reduce the emission of unburned hydrocarbons by gasoline engines by at least 20% of the rate of incorporation of the ester into the fuel, or, for example, a reduction from at least 10% to 50% of the esters incorporated into the fuel ( emission of unburned hydrocarbons can, in particular, be measured according to a method that meets the requirements of the European regulation Euro 6, ie regulation 459/2012 of 29 May 2012);

[00028] - and optionally reduce the mass and number of particles emitted per kilometer traveled by gasoline engines by at least 25% of the rate of incorporation of the ester into the fuel, or, for example, a reduction of at least 12.5% to 50% of esters incorporated in the fuel (mass and number of particles emitted per kilometer traveled, by gasoline engines, can, in particular, be measured according to a method that meets the requirements of the European regulation Euro 6, that is, regulation 459/2012 of May 29, 2012).

[00029] Advantageously, the use according to the invention may also make it possible, in addition to the uses described above:

[00030] - increase the "research" octane rating of gasoline by at least 2 points, preferably at least 3 points; and/or

[00031] - increase the "engine" octane rating of gasoline by at least 2 points, preferably at least 3 points.

[00032] These uses are very advantageous and allow to obtain a fuel that has a significantly reduced negative impact on the environment compared to the gasolines currently used.

[00033] In combination with the short esters, it is possible to use other gasoline additives, in order to increase the effects of the volatile fatty acid esters and act in synergy. In particular, it is possible to add one or more alkanes, of which the number of carbon atoms in the molecule is between 4 and 10, to gasoline, in addition to the short esters of volatile fatty acids, in order to optimize combustion. Said alkanes can originate from petroleum or originate from a biomass. Preferably, the alkanes used according to the invention originate from a biomass. Said alkanes, in combination with short esters, make it possible to further reduce emissions of nitrogen oxide and unburned hydrocarbons. Said alkanes are preferably selected from octane, isooctane, decane and mixtures thereof. In fact, said alkanes tend to improve the combustion of the mixture.

[00034] Said alkanes are preferably used at an incorporation rate between 0 and 50% by volume of fuel. They are preferably produced from volatile fatty acids originating from the anaerobic fermentation of biomass by “Kolbe” electrolysis.

[00035] In addition to short esters, gasoline and possible alkanes, it is possible to add, in combination, one or more other products to the fuel, and said products are selected from:

[00036] - additives that improve the octane index, such as organometallic compounds, such as MMT and ferrocene, or ethers, such as ETBE or TAME, or aromatic hydrocarbons, such as toluene,

[00037] - additives that improve lubrication, such as medium esters, such as hexyl valerate, hexyl caproate or longer esters,

[00038] - products that reduce combustion temperatures, such as nitrogen compounds, such as amines, urea or ammonia, possibly mixed with water,

[00039] - alcohols such as isopropanol, butanol, hexanol or octanol,

[00040] - and mixtures thereof.

[00041] Said additives allow, in particular and in combination with volatile fatty acid esters, to further reduce the emissions of hydrogen oxides and unburned hydrocarbons, or even improve other operating parameters of gasoline engines. The invention will be illustrated in detail by the examples and test results.

EXAMPLES EXAMPLE 1:

[00042] Use of 15% ethyl butyrate in RON 95 gasoline (85% gasoline - 15% ethyl butyrate) EXAMPLE 2:

[00043] Use of 30% ethyl butyrate in RON 95 gasoline (70% gasoline - 30% ethyl butyrate) EXAMPLE 3:

[00044] Use of 30% ethyl butyrate and 10% isooctane in RON 95 gasoline (60% gasoline - 30% ethyl butyrate - 10% isooctane) EXAMPLE 4:

[00045] Use of 50% ethyl butyrate and 20% isooctane in RON 95 gasoline (30% gasoline - 50% ethyl butyrate - 20% isooctane)

TEST RESULTS

[00046] The purpose of the tests performed is to evaluate the effect of using volatile fatty acid esters comprising a number of carbon atoms between 4 and 8 in a fuel comprising gasoline, on emissions of nitrogen oxides, unburned hydrocarbons and particles from gasoline engines, as well as the octane rating of gasoline.

[00047] Emissions tests were carried out on a spark-ignition EP6 single-cylinder engine using the compositions of examples 1 to 4, compared to RON 95 gasoline alone.

[00048] The RON octane index measurements were carried out in the laboratory, in accordance with the regulatory standards of the French fuel specifications.

[00049] The operational protocol of the tests is described below:

[00050] 8 engine points per fuel mixture implemented to cover a representative use of a driving cycle:

[00051] - 1500 rpm, 4, 8, 12 bar and maximum AIP

[00052] - 2,000 rpm, 4, 8, 12 bar and maximum AIP

[00053] For each motor point, the spark advance is optimized in order to obtain a maximum AIP (Average Indicated Pressure). The richness of the mixture is set to 1. It takes a few minutes for the engine's thermal and exhaust emissions to stabilize. Particles are analyzed on a PBS PEGASOR probe. The results relating to nitrogen oxide emissions are given in Table 1. TABLE 1 Average Percent Reduction Emissions in Nitrogen Oxides compared to Gasoline (ppm) RON 95 RON 95 4.428.5 Example 1 4.280.8 3.3% Example 2 4,138.8 6.5% Example 3 4023.3 9.1% Example 4 3,839.7 13.3%

[00054] The results relating the emissions of unburnt hydrocarbons are given in Table 2. TABLE 2 Average Percent Reduction emissions in hydrocarbons not compared to flared (ppm) gasoline RON 95 RON 95 3,070.2 Example 1 2,832.8 7, 7% Example 2 2779.5 9.5% Example 3 2.761.5 10.1% Example 4 2695.7 12.2%

[00055] The results relating particulate emissions are given in Table 3.

TABLE 3 Average Particle Reduction Emissions (mass compared to mg/m³) gasoline RON 95 RON 95 0.01 Example 1 undetectable Example 2 undetectable Example 3 undetectable Example 4 undetectable

[00056] The results relating the octane index are given in Table 4. TABLE 4 Octane index RON RON 95 95.1 Example 1 98.1

[00057] These results show in fact that the use of short esters of volatile fatty acids simultaneously enables:

[00058] - reduce nitrogen oxide emissions

[00059] - reduce emissions of unburned hydrocarbons

[00060] - reduce particulate emissions.

[00061] It also allows to significantly increase the octane rating of gasoline.

Claims (15)

1. Use of at least one ester of a volatile fatty acid characterized by the fact that it is in a fuel for a gasoline engine to reduce the emissions of nitrogen oxides and unburned hydrocarbons from gasoline engines, at least one ester of a volatile fatty acid, which is a mono-fatty acid with an aliphatic chain of one to six carbon atoms or one of its isomers, said ester comprising a number of carbons between 4 and 8. 2. Use according to claim 1, characterized in that it is for reducing particulate emissions from gasoline engines. 3. Use according to any one of claims 1 or 2, characterized in that the volatile fatty acid ester or esters comprising a number of carbons between 4 and 8 are used at a rate of at least 15% by volume of fuel, the fuel being formed by gasoline, in which the ester or esters of volatile fatty acids comprise a number of carbons between 4 and 8, and by possible other constituents. 4. Use, according to the preceding claim, characterized in that the ester or esters of volatile fatty acids that comprise a number of carbons between 4 and 8 are used at a rate of at least 30% by volume of fuel. 5. Use according to claim 3 or 4, characterized in that the ester or esters of volatile fatty acids comprising a number of carbons between 4 and 8 are used at a rate of at least 50% by volume of fuel . 6. Use according to any of the preceding claims, characterized in that the ester or esters of volatile fatty acids comprising a number of carbons between 4 and 8 are selected from the following esters: ethyl acetate, ethyl propionate , ethyl butyrate, ethyl valerate, ethyl hexanoate, propyl acetate, propyl propionate, propyl butyrate, propyl valerate, butyl acetate, butyl propionate, butyl butyrate and mixtures thereof. 7. Use according to any of the preceding claims, characterized in that the ester or esters of volatile fatty acids comprising a number of carbons between 4 and 8 are obtained totally or partially by esterification of volatile fatty acids of origin from biomass by alcohols of biomass origin, or by esterification of volatile fatty acids produced from carbon dioxide or carbon monoxide, in a microbial fuel cell, by alcohols of biomass origin or not. 8. Use, according to any of the preceding claims, characterized in that it is to reduce the emission of nitrogen oxides by gasoline engines by at least 20% of the rate of incorporation of esters in the fuel formed by gasoline, in which the volatile fatty acid ester or esters comprise a carbon number between 4 and 8, and possible other constituents. 9. Use, according to any of the preceding claims, characterized in that it is to reduce the emission of unburned hydrocarbons by gasoline engines by at least 20% of the rate of incorporation of esters in the fuel formed by gasoline, in which the volatile fatty acid ester or esters comprise a carbon number between 4 and 8, and possible other constituents. 10. Use, according to any of the preceding claims, characterized in that it is to reduce the emission of particles by gasoline engines by at least 25% of the rate of incorporation of esters in the fuel formed by gasoline, in which the ester or volatile fatty acid esters comprise a carbon number between 4 and 8, and possible other constituents. 11. Use, according to any of the preceding claims, characterized in that it is combined to optimize combustion, with the use in fuel, of at least one alkane with a chain length between 4 and 10 carbon atoms. 12. Use according to the preceding claim, characterized in that the alkane or alkanes are selected from octane, iso-octane, decane and their mixtures. 13. Use according to claim 11 or 12, characterized in that the alkane or alkanes are derived from petroleum or obtained from a biomass. 14. Use according to any one of claims 11 to 13, characterized in that the alkane or alkanes are used at a rate between 0 and 50% by volume of the fuel formed by gasoline, in which the ester or esters of acids volatile fatty acids comprise a carbon number between 4 and 8, where the alkane or alkanes have a chain length of between 4 and 10 carbon atoms, and possible other constituents. 15. Use according to any of the preceding claims, characterized in that one or more other products are added to the fuel, wherein said products are selected from: - additives that improve the octane index, - additives that improve lubrication, - products that reduce the combustion temperature, - alcohols - esters comprising a number of carbons greater than 8, - ethers - and mixtures thereof.