FR2994573A1 - USE OF MICRONIZED PLANT POWDERS IN A LIQUID FUEL. - Google Patents

Abstract

The present invention relates to a method for preparing a fuel composition, characterized in that it comprises the following steps: a) Cryomilling reduction of at least one biomass product to obtain a powder; b) mixing the powder obtained in step a) with at least one liquid fuel. According to an advantageous embodiment of the invention, the method of the invention may comprise, after step a), a step alpha) in which the biomass product is fermented in the presence of microorganisms. In addition, the present invention has the second object a fuel composition obtainable by said method, comprising the powder of at least one cryomilled biomass product and at least one liquid fuel.

Description

The present invention relates to a method for preparing a fuel composition comprising powders of biomass products and at least one liquid fuel, and a fuel composition obtainable by said method. This process comprises the following steps: a) Cryomilling reduction of at least one biomass product to obtain a powder; b) mixing the powder obtained in step a) with a liquid fuel. Until now, the use of biomass for "renewable" biofuels has been to use vegetable oils, or to ferment the biomass with yeasts to produce alcohol which was then obtained by distillation with a high cost price compared to its energy value. Most current biofuels require at least one stage of biomass transformation. Biomass is thus used as a raw material from which are obtained either oils or alcohols, which are used as fuels.

The oil is extracted by cold pressing, hot, or even with an organic solvent, from oleiferous plant species, such as oil palm, sunflower, rapeseed, jatropha or castor oil. Depending on the oil obtained, it can be used directly or transformed before use. Thus, crude vegetable oil (HVB) can be used directly in diesel engines, pure or in mixture. However, especially because of its relatively high viscosity, the use of a large fraction of oil requires the use of a suitable engine. Alternatively, the oils can be processed to obtain biodiesel. In this case, the triglycerides which constitute these vegetable oils undergo transesterification with methanol or ethanol, so as to produce vegetable oil esters, in particular vegetable oil methyl esters (VOMEs) and ethyl esters. of vegetable oil (EEHV). These smaller molecules can then be used as fuel in compression ignition engines.

Alcohols, for their part, are produced from plant species known for their high sugar content, such as sugar cane, sugar beet, corn, wheat or recently olive. The bio-alcohols (biologically obtained alcohols) are then obtained by alcoholic fermentation of these sugars by bacteria or by yeasts. For example, bioethanol is obtained by fermentation with yeasts of the genus Saccharomyces, while fermentation with Clostridium acetobutylicum leads to the production of butanol-1, dihydrogen, acetic acid, propionic acetone, isopropanol and ethanol. Bioethanol can partially or completely replace gasoline. A small proportion of ethanol can also be added in diesel, giving then oxygenated gas oil. Bioethanol can also be etherified to obtain ethyl tertiary butyl ether (ETBE) which is used as a 15% additive to gasoline instead of lead. The production of these biofuels, if it reduces the use of fossil fuels, whose resources are by definition limited, requires a mass production of particular plants, leading to an intensive monoculture devastating for the environment, and to the use of agrarian land for the production of non-food crops. These biofuels therefore do not completely solve the problem of the use of renewable carbon elements. Currently, biofuels compete with human food because they come from edible oils or fermented sugars that are human foods. FAO and OECD have been shocked by this competition, which is detrimental to the future of humanity. Some have considered the use of non-specific plant waste to produce biofuels, in order to limit the use of intensive monoculture and at the same time allow the recycling of this waste. These so-called "second generation" biofuels are fuels that also value all or part of the structural components of biomass (lignin, cellulose, hemicellusosis), and not just the energy reserves of plants (starch, sugar and oil).

However, the current methods of producing these fuels require the implementation of processes comprising many steps, and which are therefore long and expensive. In addition, these steps generally consist of chemical or thermal treatments of the biomass in order to reduce it to particles small enough to be used in conventional engines. However, these treatments modify the physico-chemical characteristics of the biomass, in particular by contributing to the oxidation, which greatly reduces its content of energetic compounds. There is therefore a need for a fuel composition production process from biomass products that is simple, safe and inexpensive and that allows good conservation of the chemical compounds included in the biomass and especially to find raw materials that do not not be food for humans and livestock. The inventors have discovered that it is possible to reduce very fine powder biomass simply and economically, without altering its content, in particular its chemical composition. Thus, the inventors have discovered that the biomass products can be reduced to powder so as to obtain very fine powders, the particles of which typically have a size of about 901.1m to 1001.1m by cryomilling. The cryomilling technique makes it possible to avoid the use of solvents or of high temperatures, and thus makes it possible to reduce the biological material in powder without chemically denaturing it. The particles thus produced having been stirred in the mill in an atmosphere of nitrogen and not of air containing oxygen, are therefore not oxidized. Indeed, all plants contain substances that burn easily, which means that they oxidize easily: essential oils, fats, cellulose, lignin especially, as well as flavonoids. The inventors have found that all these oxidizable materials reduced by half in plants crushed without nitrogen. This process of cryobrushing of plant powders thus makes it possible to conserve almost 100% of the energy capacities of the plants. The inventors have furthermore discovered that the particles of biomass products thus obtained are advantageously used in admixture with fuels such as gasoline, kerosene, diesel, fuel oil, diesel fuel, iso-octane, iso-propane and their mixtures, to produce fuel fuels. Indeed, the inventors have discovered that the fuel fuels obtained by the process of the invention are more energetic and less polluting than the known fuel fuels. On the one hand, the use of non-chemically modified biomass makes it possible to retain all the organic compounds initially included in the biomass, and thus to use powders of high energy biomass products. On the other hand, the use of powders of biomass products that contain flavonoids makes the exhaust gases less loaded with particles, which are thought to be carcinogenic. The inventors have furthermore discovered that the fuel fuels prepared according to the process of the invention are particularly interesting in that they do not require any integral modification of the engines of the vehicles, because of the small size of the particles they contain. Indeed, it is enough to slightly modify the engines, for example the diesel engines, by removing the filters in the injector, by widening certain pipes, and putting an agitator in the tank. These changes are minor compared to those required for other existing fuels.

Thus, the present invention relates to a process for preparing a fuel composition, characterized in that it comprises the following steps: a) Cryomilling reduction of at least one biomass product to obtain a powder; b) mixing the powder obtained in step a) with at least one liquid fuel. In addition, the present invention has the second object a fuel composition obtainable by said method, comprising the powder of one or more products of cryoskilled biomass (s) and at least one liquid fuel.

According to the invention, the particles of the powder obtained after freeze-grinding have a mean size of less than 1501.1m, preferably between 501.1m and 1501.1m, even more preferentially between 80 and 1101.1m. The size of the biomass particles obtained can be easily determined by those skilled in the art according to any known technique. This size can thus be very easily determined by observation of the particles under a microscope, using a graduated scale. For a more precise determination of the average particle size of a given quantity of biomass powder, it is for example possible to measure the size of the particles contained in a representative sample of this quantity, and to determine the average thereof. Cryo-grinding is defined herein as any mechanical grinding technique in which the products are ground in the presence of liquid nitrogen at about -100 ° C to -196 ° C, or in the presence of liquid nitrogen at about -100 ° C. ° C and -196 ° C before and / or during mechanical grinding. For example, cryomilling can be carried out as follows, illustrated in FIG. 1. Biomass products are brought into the presence of nitrogen maintained at -196 ° C., in the liquid state. The products thus cryogenized are then passed through a mill. The particles obtained constitute the powder of biomass products. These particles can then be stirred at room temperature so as to evacuate the nitrogen. Cryomilling can for example be carried out using a grinder, typically formed of a tube 40 cm long and a diameter of 50 cm, the surface is perforated. The tube is closed at both ends. The biomass products are initially placed in the presence of liquid nitrogen, then are projected at a very high speed on the surface of the tube, therefore on a perforated surface, which makes it possible to reduce them to powder. The atmosphere inside the tube is nitrogen without oxygen.

The inventors have furthermore discovered that the various biomass products used in the process could advantageously be fermented after their reduction to powder, for example in water, or in the presence of microorganisms, in order to enrich said biomass with organic products. preferentially in fats. The alcohol resulting from the fermentation is kept in the mixture and makes the powder more energetic. Yeasts or bacteria can also be used in these premixes with a little water, microorganisms that secrete fatty substances, which will be preserved in the mixture, making this product more energetic. The inventors have, for example, discovered that fermented biomass products in the presence of organisms of the family Rhodotorula, Candida, Aspergillus, Saccharomycopsis, Arthrobacter, Cryptococcus, Lipomyces, Zygohpomyces, Sphacelotheca make it possible subsequently to obtain richer powders. in fat. The inventors furthermore determined that the fermented biomass products in the presence of Rhodotorula toruloids, Rhodosporidium toruloides, Candida used, Rhodotorula Gracilis, Aspergilus oryzae, Saccharomycopsis fibuligera, Arthrobacter AK19, Cryptococcus albidus, Lipomyces starkeyi, Zygohpomyces starkeyi and Sphacelotheca reliana, allow to obtain powder particularly rich in fat. Thus, according to one embodiment of the invention, the method of the invention comprises the fermentation of biomass after cryobrushing. According to an advantageous embodiment of the invention, the process of the invention comprises, after step a), a step ci) in which the biomass products are fermented in the presence of microorganisms chosen from the organisms of the family. Rhodotorula, Candida, Aspergillus, Saccharomycopsis, Arthrobacter, Cryptococcus, Lipomyces, Zygohpomyces, Sphacelotheca, and mixtures thereof. According to a particularly advantageous embodiment of the invention, the process of the invention comprises, after step a), a step c1) in which the biomass products are fermented in the presence of microorganisms chosen from the list consisting of Rhodotorula toruloid, Rhodosporidium toruloid, Candida used, Rhodotorula Gracilis, Aspergilus oryzae, Saccharomycopsis fibuligera, Arthrobacter AK19, Cryptococcus albidus, Lipomyces starkeyi, Zygohpomyces starkeyi and Sphacelotheca reliana, and mixtures thereof. According to the invention, the biomass product is any plant product: logging waste such as for example dried leaves and tree branches, dry agricultural residues such as corn stovers (maize plants). after the harvest of the ears) or soybeans after harvesting peas, fermentation waste (the "grain distillers"), spirits production waste such as all the waste that remains after the production of the whiskey, vodka, bottoms of wine vats, with all the corpses of brewer's yeast, waste from the wood and paper industry, wastes that remain after the production of plant extracts for medicine or cosmetics, harvested and dried algae, compost, manure including domestic animals.

According to the present invention, agricultural dry residues are defined as the part of the plants which is inedible to humans and left behind after harvesting. It may be as well as cereal straws, stems, leaves, and / or plant roots.

According to the present invention, logging waste consists of damaged or unwanted branches, twigs, leaves and / or trunks that are left in the forest. According to the present invention, waste from the wood industry includes sawdust and scrap, while waste from the paper industry includes used paper as well as black liquor. According to one embodiment of the invention, the biomass product (s) is (are) chosen from the list consisting of plants, forestry waste, agricultural dry residues, waste fermentation, wood and paper industry waste, spirits production waste, beer yeast corpses, compost, manure, and mixtures thereof. According to the invention, it is not necessary to use a single part of the plant, and all the plants can be used. This is an elegant and practical solution to the problem of sorting plant waste that can be used. Indeed, it is possible to harvest oleaginous plants such as sunflower, soybean, canola, flax, castor, in their entirety in the field, without the need to use expensive and long sorting methods. 100% of the biomass is used: the fats and the plants themselves. The powder of the biomass products will then consist of the very fine plant powder, as well as the oils contained in the plant.

According to one embodiment of the invention, the biomass product (s) is (are) dried before being reduced to powder by cryomilling. According to the invention, the liquid fuel is any combustible compound or any liquid fuel composition at ambient temperature, for example a fossil fuel fuel or a biofuel.

According to one embodiment of the invention, the liquid fuel is selected from the list consisting of gasoline, kerosene, diesel, fuel oil, gas oil, isooctane, iso-propane, and mixtures thereof.

The inventors have further discovered that the compositions comprising the powder of one or more biomass product (s) and in particular diesel are particularly homogeneous. In these compositions in particular, the powder of one or more biomass products precipitates little.

According to a preferred embodiment, the liquid fuel is diesel. The inventors have determined that it is thus possible to implement such a process to obtain fuel compositions comprising from 20% to 80% of powder of one or more biomass products with at least one fuel fuel, by weight relative to to the total weight of the composition.

According to one embodiment of the invention, the fuel composition obtainable by the process comprises 20% to 80%, preferably 50% to 60%, of said powder, by weight relative to the total weight of the composition. The inventors have furthermore discovered that it is possible to improve the viscosity of the composition obtainable by the method of the invention, by adding a step thereto in which the mixture obtained at the end of step b) may be mixed with water, or by mixing the powder obtained at the end of step a) with water, before performing step b). Thus, according to an advantageous embodiment, the method of the invention further comprises, after step b), the following step: c) adding water to the mixture obtained in step b). According to another embodiment, the method of the invention further comprises, after step a) and before step b), the following step: a) adding water to the powder obtained at step a). According to one embodiment of the invention, the fuel composition obtainable by the process may further comprise 5 to 10% water by weight relative to the total weight of the composition. A mixture of nettle roots, hawthorn twigs and olive leaves were crushed by cryomilling at temperatures of about -20 to -40 degrees Celsius. The particle size was 60% less than 50 microns and the rest between 70 and 50 microns, then this powder was mixed with diesel fuel. Tests have been carried out on diesel trucks and it has been found that the engines operate perfectly with these cryogrinded plant powders in proportions of 10 to 80% by weight of powder, relative to the total weight of the mixture. It has also been found that the 50/50 mixture (weight of cryogrown plants / weight of diesel fuel) has been the most successful engine climbing even on 25 ° slopes. The exhausts did not project any incandescent product.

Claims (12)

REVENDICATIONS1. Process for preparing a fuel composition, characterized in that it comprises the following steps: a) Cryomilling reduction of at least one biomass product to obtain a powder; b) mixing the powder obtained in step a) with at least one liquid fuel. 2. Method according to claim 1, characterized in that the particles of the powder obtained after freeze-grinding have a mean size of between 50 and 1501.1m. 3. Method according to claim 1 or 2, characterized in that said method further comprises, after step a), the following step of: ci) Fermentation of biomass. 4. Method according to claim 3, characterized in that the biomass product is fermented in the presence of microorganisms selected from the family of Rhodotorula, Candida, Aspergilus, Saccharomycopsis, Arthrobacter, Cryptococcus, Lipomyces, Zygolipomyces, Sphacelotheca, and their families. mixtures. 5. Method according to claim 3 or 4, characterized in that the biomass product is fermented in the presence of microorganisms selected from the list consisting of Rhodotorula toruloides, Rhodosporidium toruloid, Candida used, Rhodotorula Gracilis, Aspergilus oryzae, Saccharomycopsis fibuligera, Arthrobacter AK19 , Cryptococcus albidus, Starkeyi Lipomyces, Zygohpomyces starkeyi and Sphacelotheca reliana, and mixtures thereof. 6. Process according to any one of claims 1 to 5, characterized in that the biomass product is chosen from the list consisting of plants, forestry waste, agricultural dry residues, waste from the wood and paper industry, spirits production waste, brewery yeast corpses, compost, manure, and mixtures thereof. 7. Method according to any one of claims 1 to 6, characterized in that the liquid fuel is selected from the list consisting of gasoline, kerosene, diesel, fuel oil, gas oil, iso-octane, isopropane, and mixtures thereof. 8. Method according to claim 7, characterized in that the liquid fuel is diesel. 9. Process according to any one of claims 1 to 8, characterized in that it further comprises, after step b), the following step: c) Adding water to the mixture obtained in step b). 10. A fuel composition obtainable by a process as claimed in any one of claims 1 to 9, comprising powder of at least one cryomed biomass product and at least one liquid fuel. 11. Combustible composition according to claim 10, characterized in that it comprises 20% to 80%, preferably 50% to 60%, of said powder, by weight relative to the total weight of the composition. 25 12. Combustible composition according to claim 10 or 11, characterized in that it may further comprise 5 to 10% water, by weight relative to the total weight of the composition. 10