Biomass-containing fuel

Abstract

The purpose of the present invention is to provide a biomass-containing fuel having excellent combustibility similar to a fuel such as heavy oil. The present invention is a biomass-containing fuel comprising a fuel oil and a carbonized product produced by steam roasting plant biomass.

Description

Biomass-containing fuel

[0001] The present invention relates to a biomass-containing fuel, and more particularly to a biomass-containing fuel that is suitable for use as a fuel for diesel engines, boilers, gas turbines, etc., and as a sustainable aviation fuel.

[0002] Slurry fuels, which are made by adding liquids such as heavy oil to powdered solid fuels such as coal, are being developed as an alternative to liquid fuels such as heavy oil. Regarding coal slurry fuels, for example, Patent Document 1 discloses a fuel oil composition comprising (i) a granular material having particles of at least about 90% by volume of about 20 microns or less in diameter, and (ii) a liquid fuel oil, wherein the granular material is present in an amount of at most about 30% by mass relative to the total mass, the granular material is a carbonaceous material, and the ash content of the granular material is less than 5% by mass. Patent Document 2 also discloses a fuel oil composition.

[0003] The increase in carbon dioxide emissions due to the mass consumption of fossil fuels is a major factor in global warming, and there is a demand for a reduction in carbon dioxide emissions. Plant biomass such as wood emits carbon dioxide when burned, but this carbon dioxide is absorbed during the plant's growth process and does not affect the increase or decrease in carbon dioxide in the atmosphere. Therefore, it is expected that plant biomass will be used as fuel to realize a carbon-free society. Patent Document 3 discloses a method for producing charcoal slurry fuel, in which charcoal is mixed with a liquid for slurrying.

[0004] Japanese Patent Application Laid-Open No. 2021-101030 Japanese Patent Application Laid-Open No. 2019-513840 Japanese Patent Application Laid-Open No. 2015-221877

[0005] As mentioned above, fuels using plant biomass have been developed in the past, but there is a demand for further development of biomass-containing fuels that have excellent combustibility similar to fuels such as heavy oil.

[0006] The present invention has been made in view of the above-mentioned current situation, and aims to provide a biomass-containing fuel that has excellent combustibility similar to fuels such as heavy oil.

[0007] The inventors conducted extensive research into fuels containing biomass and discovered that a biomass-containing fuel containing steamed carbonized plant biomass and fuel oil has excellent combustibility, similar to fuels such as heavy oil. They then came to the conclusion that this could brilliantly solve the above-mentioned problems, leading to the present invention.

[0008] The present invention encompasses the following biomass-containing fuels, etc. [1] A biomass-containing fuel comprising a steamed charcoal of plant biomass and fuel oil. [2] The biomass-containing fuel according to [1] above, wherein the steamed charcoal of plant biomass is steamed at a temperature of 250 to 450°C. [3] The biomass-containing fuel according to [1] or [2] above, wherein the steamed charcoal of plant biomass has an average circularity (area) of particles within ±10% of the average particle diameter (volume basis) measured by dynamic light scattering of 0.5 to 1. [4] The biomass-containing fuel according to any of [1] to [3] above, wherein the proportion of particles in the steamed charcoal of plant biomass having a particle diameter of 50 μm or less is 95% or more. [5] The biomass-containing fuel according to any of [1] to [4] above, wherein the steamed charcoal of plant biomass has an average particle diameter of 0.1 μm or more and 20 μm or less. [6] The biomass-containing fuel according to any one of [1] to [5] above, wherein the content of the steamed charcoal of plant biomass is 10 to 60 mass% relative to 100 mass% of the biomass-containing fuel. [7] The biomass-containing fuel according to any one of [1] to [6] above, wherein the viscosity of the biomass-containing fuel is 1000 mPa·s or less. [8] A method for producing a biomass-containing fuel, comprising: a step of carbonizing plant biomass by steaming; a step of pulverizing the charcoal obtained in the carbonization step; and a step of mixing the pulverized material obtained in the pulverization step with fuel oil.

[0009] The biomass-containing fuel of the present invention has the above-described configuration and has excellent combustibility similar to fuels such as heavy oil, and therefore can be suitably used as fuel for diesel engines, boilers, gas turbines, etc., or as sustainable aviation fuel.

[0010] Preferred embodiments of the present invention will be specifically described below, but the present invention is not limited to the following description and can be appropriately modified and applied within the scope of the present invention. Note that a combination of two or more of the individual preferred embodiments of the present invention described below also falls within the scope of the present invention.

[0011] [Biomass-containing fuel] The biomass-containing fuel of the present invention contains a steamed charcoal of plant biomass and fuel oil. The biomass-containing fuel has excellent dispersibility due to the use of the steamed charcoal of plant biomass, and therefore excellent combustibility. The content of the steamed charcoal of plant biomass in the biomass-containing fuel is not particularly limited, but is preferably 10 to 60 mass% relative to 100 mass% of the biomass-containing fuel. This allows the amount of fuel oil used to be more sufficiently reduced, and CO2 can be more effectively reduced. ２ The content of the steamed carbonized plant biomass is more preferably 15 to 55 mass%, further preferably 20 to 50 mass%, and particularly preferably 25 to 45 mass%.

[0012] The content of fuel oil in the biomass-containing fuel is not particularly limited, but is preferably 40 to 90 mass% relative to 100 mass% of the biomass-containing fuel, more preferably 45 to 85 mass%, even more preferably 50 to 80 mass%, and particularly preferably 55 to 75 mass%.

[0013] The biomass-containing fuel may contain other components in addition to the steamed carbonized plant biomass and fuel oil. The content of the other components is not particularly limited, but is preferably 20% by mass or less relative to 100% by mass of the biomass-containing fuel. More preferably, it is 10% by mass or less, and even more preferably, it is 5% by mass or less.

[0014] The biomass-containing fuel may contain a dispersant as another component, but the biomass-containing fuel of the present invention has excellent dispersibility even when no dispersant is used. The content of the dispersant is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less, relative to 100% by mass of the steamed and baked carbonized plant biomass.

[0015] The biomass-containing fuel preferably has a viscosity of 1000 mPa·s or less at 25°C. This provides the biomass-containing fuel with superior fluidity, making it easier to handle and transport. The viscosity of the biomass-containing fuel is more preferably 800 mPa·s or less, even more preferably 600 mPa·s or less, and particularly preferably 500 mPa·s or less. However, even if the viscosity at 25°C is 1000 mPa·s or more, if it becomes 1000 mPa·s or less when heated to 80°C, it can be used without problems if the fuel tank is equipped with heating equipment. The viscosity of the biomass-containing fuel can be measured by the method described in the Examples.

[0016] The biomass-containing fuel may have thixotropy or rheopexy, but preferably has thixotropy.

[0017] The essential and optional components contained in the biomass-containing fuel of the present invention will be further described below.

[0018] <Steamed Charcoal of Plant Biomass> The steamed charcoal of plant biomass is not particularly limited as long as it is obtained by carbonizing plant biomass by steaming. The plant biomass is not particularly limited as long as it is an organic material derived from a plant, and examples of plants include woody plants and herbaceous plants. Examples of woody plants include coniferous trees such as cedar, fir, cypress, Japanese cypress, pine, ginkgo, Japanese nut, and yew, and broad-leaved trees such as eucalyptus, acacia, birch, beech, oak, katsura, sawtooth oak, cherry, zelkova, maple, chestnut, oak, paulownia, poplar, teak, and mahogany. Among these, cedar and acacia are preferred. Examples of herbaceous plants include rice (straw, rice husk), wheat (straw, rice husk), buckwheat (straw, rice husk), sugarcane (bagasse), Erianthus, corn, rapeseed, soybean, palm, reed, bamboo, bamboo, and sugar beet. Of these, sugarcane (bagasse) is preferred. As the plant for the plant biomass, woody plants are preferred because they have a low ash content.

[0019] The ash content of the steamed carbonized plant biomass is preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 3% by mass or less. The ash content can be measured, for example, according to JIS M8812:2004.

[0020] The steamed carbonized plant biomass preferably has a nitrogen content of 1.0% by mass or less, more preferably 0.7% by mass or less, and even more preferably 0.5% by mass or less. The nitrogen content can be measured, for example, according to JIS M8813:2004.

[0021] The carbonized product of plant biomass preferably has a sulfur content of 0.5% by mass or less, more preferably 0.1% by mass or less, and even more preferably 0.05% by mass or less. The sulfur content can be measured, for example, according to JIS M8813:2004.

[0022] The steamed carbonized plant biomass preferably has an average particle circularity (area) of 0.5 or more and 1 or less, the average particle diameter (volume basis) of which is within ±10% of the average particle diameter as measured by dynamic light scattering. Because plant biomass is carbonized while retaining the plant tissue structure, the carbonized product also retains a structure similar to plant tissue, and the pulverized product obtained by pulverizing such a carbonized product also retains a complex shape. When the carbonized particles have a complex shape, the interaction between particles in the biomass-containing fuel may increase, resulting in increased viscosity. However, if the particle circularity (area) is within the above range, this increase in viscosity can be suppressed and dispersion fluidity can be further improved. Furthermore, by more thoroughly pulverizing the steamed carbonized plant biomass, the complex shape of the plant biomass is reduced, but the viscosity increases with increasing surface area. However, by pulverizing the particle circularity (area) within the above range, the increase in viscosity associated with increased surface area can be suppressed. The average circularity (area) of the particles is more preferably 0.52 to 1, even more preferably 0.55 to 1, still more preferably 0.6 to 1, and particularly preferably 0.65 to 1. The circularity (area) of the particles is the ratio of the projected area of ​​each particle to the circle-equivalent area calculated from the circumferential length of the particle, and is given by: Circularity = 4π × [projected area of ​​particle] × (1 / (circumferential length of particle) ２ ) and can be measured by the method described in the Examples.

[0023] The steamed charcoal of plant biomass preferably has a particle size of 100 μm or less at a rate of 95% or more. Plant tissue has a honeycomb structure, and the charcoal also has a similar shape. When crushed, the honeycomb structure is broken down, and this complex structure significantly affects the fluidity during dispersion. However, if the particle size rate of 100 μm or less is 95% or more, the influence of the complex structure of the plant tissue is eliminated, and the fluidity of the dispersed charcoal is further improved. This results in the biomass-containing fuel of the present invention being easier to handle and transport. The steamed charcoal of plant biomass more preferably has a particle size of 50 μm or less at a rate of 95% or more, and even more preferably has a particle size of 30 μm or less at a rate of 95% or more. The particle size of the steamed charcoal of plant biomass and the calculation of the particle size rate can be performed using the method described in the Examples.

[0024] The steamed carbonized plant biomass preferably has an average particle size of 0.1 μm or more and 20 μm or less. If the average particle size is 20 μm or less, the fluidity of the carbonized product during dispersion is further improved, and if the average particle size is 0.1 μm or more, thickening due to an increase in the specific surface area of ​​the carbonized product can be sufficiently suppressed. The average particle size is more preferably 0.5 to 15 μm, even more preferably 1 to 10 μm, and particularly preferably 1 to 5 μm. The average particle size of the steamed carbonized plant biomass can be measured by the method described in the Examples.

[0025] The steamed charcoal of plant biomass is obtained by steaming the raw plant biomass. The resulting charcoal is semi-carbonized and has excellent pulverizability. The steamed charcoal of plant biomass is preferably produced by a process of carbonizing plant biomass by steaming. The steaming temperature is not particularly limited, but is preferably 250 to 550°C. A steaming temperature of 250°C or higher allows carbonization to proceed efficiently and provides excellent productivity, while a steaming temperature of 550°C or lower further improves the yield of the char. Furthermore, when the steaming temperature is within the above range, the molecular weight of the volatile components obtained in the process of carbonizing the plant biomass falls within a suitable range, and the obtained volatile components can also be suitably used as fuel, etc. Furthermore, when the steaming temperature is within the above range, hydrophobic components remain on the surface of the resulting char, which is thought to improve wettability with fuel oil and contribute to the dispersibility of the char in biomass-containing fuel. The steaming temperature is more preferably 250 to 500° C., even more preferably 260 to 450° C., even more preferably 300 to 430° C., and particularly preferably 350 to 400° C. Preferred conditions for the step of carbonizing the plant biomass by steaming will be described later in the method for producing a biomass-containing fuel.

[0026] <Fuel Oil> The fuel oil contained in the biomass-containing fuel of the present invention is not particularly limited as long as it is an oil that can be used as a fuel. In the case of fossil fuels, it is preferably a highly distilled product derived from crude oil. Liquid fuel oils such as diesel, heavy oil, kerosene, naphtha, gasoline, and jet fuel oil are more preferred, and diesel, heavy oil, and kerosene are even more preferred. Heavy oils include heavy oil A, heavy oil B, and heavy oil C. The fuel oil may also contain bioalcohol and / or biodiesel. The bioalcohol is a biomass-derived alcohol such as ethanol, isopropanol, or butanol obtained by fermenting carbohydrates with bacteria, etc., and the biodiesel is a biodiesel fuel oil obtained by processing oils and fats obtained from vegetable oils, seaweed, etc. Furthermore, the fuel oil may contain fuel-usable components and their modified products, which are obtained by collecting and cooling volatile components during the steaming process. To reduce carbon dioxide emissions, it is preferable to minimize the use of petroleum-based fuel oil and mix in more biofuel oil.

[0027] The viscosity of the fuel oil is not particularly limited, but is preferably 500 mPa s or less, more preferably 300 mPa s or less, even more preferably 100 mPa s or less, and particularly preferably 50 mPa s or less. The viscosity of the fuel oil can be measured by the same method as that for the viscosity of the biomass-containing fuel.

[0028] <Other Components> The biomass-containing fuel of the present invention may contain other components in addition to the steamed carbonized plant biomass and fuel oil. The other components are not particularly limited, but may include stabilizers, separation reducing agents, thickeners, viscosity reducers, biofuels, dispersants, ignition agents, cetane number improvers, lubricants, etc.

[0029] The stabilizer is not particularly limited, but examples thereof include polyalkylene oxide adducts of alcohols, and among these, polyalkylene oxide adducts of glycerin are preferred.

[0030] The thickener is not particularly limited, but examples thereof include polymeric materials such as polysaccharides, polyacrylamides, polyalkylene oxides, polyacrylic acids and salts thereof, acrylic polymers, and polyvinyl alcohols.

[0031] The viscosity reducing agent is not particularly limited, but examples thereof include glycol monoethers, glycol diethers, phenyl glycol ethers, and benzyl glycols.

[0032] The dispersant is not particularly limited, but examples thereof include (i) polyalkylarylsulfonate-based dispersants such as naphthalenesulfonic acid formaldehyde condensates; melamine formalin resin sulfonate-based dispersants such as melamine sulfonic acid formaldehyde condensates; aromatic aminosulfonate-based dispersants such as aminoarylsulfonic acid-phenol-formaldehyde condensates; lignin sulfonate-based dispersants such as lignin sulfonates and modified lignin sulfonates; polystyrene sulfonate-based dispersants; nonylphenyl sulfonate (ii) copolymers obtained from polyalkylene glycol mono(meth)acrylate monomers, (meth)acrylic acid monomers, and monomers copolymerizable with these monomers, as described in JP-B No. 59-18338 and JP-A No. 7-223852; unsaturated (poly)alkylene glycol copolymers as described in JP-A No. 10-236858, JP-A No. 2001-220417, JP-A No. 2002-121055, and JP-A No. 2002-121056; (iii) polyvinylpyrrolidone; (iv) polyacrylic acid; (v) copolymers obtained from (alkoxy)polyalkylene glycol mono(meth)acrylates, phosphoric acid monoester monomers, and phosphoric acid diester monomers, each of which has a (poly)oxy group in the molecule, such as copolymers obtained from (alkoxy)polyalkylene glycol mono(meth)acrylates, phosphoric acid monoester monomers, and phosphoric acid diester monomers, as described in JP-A-2006-52381; Copolymers having an alkylene group and a phosphate ester group; as described in JP-A-2008-517080, polycondensation products comprising a monomer having a (poly)oxyalkylene group and an aromatic ring group and / or a heterocyclic aromatic group, a monomer having a phosphoric acid (salt) group and / or a phosphate ester group and an aromatic ring group and / or a heterocyclic aromatic group, and an aldehyde compound; as described in JP-A-2015-508384, dispersants having an aromatic triazine structural unit, a polyalkylene glycol structural unit, and a phosphate ester structural unit;(vi) anionic surfactants such as alkyl sulfate ester salts, higher alcohol sulfate ester salts, nonionic ether sulfate ester salts, olefin sulfate ester salts, polyoxyethylene alkyl (alkylphenol) sulfate ester salts, alkyl allyl sulfonates, dibasic acid ester sulfonates, alkyl benzene sulfonates, alkyl naphthalene sulfonates, dialkyl sulfosuccinates, alkyl phosphate ester salts, and acylsarcosinates; (vii) cationic surfactants such as alkylamine salts, quaternary amine salts, and alkylpyridinium sulfate salts; (viii) nonionic surfactants such as polyoxyalkyl ethers, polyoxyethylene alkylphenol ethers, oxyethylene-oxypropylene block polymers, polyoxyethylene alkylamines, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, alkyltrimethylammonium chloride, alkyldimethylbenzylammonium chloride, polyoxyethylene fatty acid esters, aliphatic alcohol polyoxyethylene ethers, polyhydric alcohol fatty acid esters, and fatty acid ethanolamides; and (ix) amphoteric surfactants such as alkyl betaines.

[0033] The weight average molecular weight of the dispersant is not particularly limited, but is preferably 100 to 1,000,000, more preferably 200 to 500,000, and even more preferably 300 to 100,000. The weight average molecular weight of the dispersant can be measured by GPC.

[0034] [Method for producing biomass-containing fuel] The method for producing biomass-containing fuel of the present invention is not particularly limited, but it is preferable to produce the fuel by carrying out the steps of carbonizing plant biomass by steaming, pulverizing the carbonized product obtained in the carbonization step, and mixing the pulverized product obtained in the pulverization step with fuel oil. A method for producing biomass-containing fuel including the steps of carbonizing plant biomass by steaming, pulverizing the carbonized product obtained in the carbonization step, and mixing the pulverized product obtained in the pulverization step with fuel oil also constitutes one aspect of the present invention.

[0035] The carbonization step is not particularly limited as long as the plant biomass is carbonized by steaming, but the steaming temperature is preferably 250 to 550°C, more preferably 250 to 500°C, even more preferably 260 to 450°C, still more preferably 300 to 430°C, and particularly preferably 350 to 400°C.

[0036] The pressure in the system during the carbonization step is not particularly limited, but is preferably 0.1 to 100 atmospheres, more preferably 0.5 to 10 atmospheres, even more preferably 1 to 5 atmospheres, and particularly preferably 1 to 3 atmospheres.

[0037] The oxygen concentration in the system during the carbonization step is not particularly limited, but is preferably 0 to 5%, more preferably 0 to 3%, and even more preferably 0 to 1%.

[0038] The baking time in the carbonization step is not particularly limited, but is preferably 3 minutes to 3 hours, and more preferably 5 minutes to 1 hour.

[0039] The equipment for carrying out the carbonization step is not particularly limited, but examples thereof include horizontal moving-bed reactors such as mesh belt continuous calciners, tunnel kilns and rotary kilns; and twin-screw extruders.

[0040] The pulverization step is not particularly limited as long as it pulverizes the carbonized material obtained in the carbonization step, and may be wet pulverization or dry pulverization. The pulverizer used in the pulverization step is not particularly limited, and examples include a hammer mill, a ball mill, a tube mill, a rod mill, a jet mill, and a bead mill. From the viewpoint of increasing the circularity of the particles, a bead mill is preferred. Furthermore, when pulverization is performed using a bead mill, the circularity of the particles can be increased by adjusting the operating conditions of the bead mill, such as the material, size, and amount of beads, the amount of raw material input, and the agitator rotation speed. For example, by using beads with a relatively small diameter and setting the agitator rotation speed low, the circularity can be further improved by operating in a manner that suppresses impact force and allows frictional force to predominate.

[0041] The mixing step is not particularly limited as long as it mixes the pulverized material obtained in the pulverization step with fuel oil, but it is preferable to disperse the pulverized material in the fuel oil by stirring or ultrasonic waves. In the mixing step, it is preferable to use a stirrer such as a disperser, homogenizer, line mixer, or static mixer, or an ultrasonic disperser. Furthermore, fuel oil may be introduced into the pulverizer in the latter half of pulverization, and dispersion may be performed simultaneously with pulverization.

[0042] The atmosphere in the mixing step is not particularly limited, and may be an air atmosphere or an inert gas atmosphere, but it is preferable to perform the mixing step while introducing an inert gas such as nitrogen. In addition, the mixing step is preferably performed in an explosion-proof facility.

[0043] In the method for producing a biomass-containing fuel of the present invention, a step of drying the raw plant biomass is preferably carried out before the carbonization step. The drying step is not particularly limited as long as it dries the raw plant biomass, but it is preferable to dry the raw plant biomass until the moisture content is 25% or less.

[0044] In the method for producing a biomass-containing fuel of the present invention, it is preferable to carry out a step of crushing the raw plant biomass into pieces of 50 mm or less before the carbonization step.

[0045] In the method for producing a biomass-containing fuel of the present invention, a step of filtering the composition obtained in the mixing step may be carried out after the mixing step. The filtering step preferably uses a wire mesh of 50 to 300 mesh.

[0046] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "%" means "% by mass."

[0047] <Method of measuring particle size> Pulverized biomass carbonized material was added to a 10% aqueous solution of naphthalenesulfonic acid formalin condensate so that the concentration was 10%, and the dispersion was dispersed for 15 minutes using an ultrasonic disperser. The dispersion particle size distribution of this was measured using a laser diffraction / scattering particle size distribution analyzer (dynamic light scattering particle size analyzer, LA-950V2, manufactured by Horiba, Ltd.).

[0048] <Method for measuring circularity> 10 mg of a sample was placed in a beaker, and an aqueous dispersant solution (Super T-Pol (manufactured by C.B.S. Co., Ltd.)) was added to make the volume 30 ml, followed by dispersion treatment in an ultrasonic cleaner for 2 minutes to prepare a measurement solution. The obtained measurement solution was used to measure the circularity of particles under the following measurement conditions using the following device: Analyzer: Dynamic particle size analyzer Paasche Analyzer PAS (manufactured by Hosokawa Micron Corporation) Method: Flat sheath flow method Measurement conditions Lens: Standard Measurement range: 0.5 to 300 μm Number of detected particles: Approximately 10,000 Data on the circularity (area) of particles falling within a range of ±10% of the average particle size (volume basis) measured by the dynamic light scattering particle size analyzer in the above <Method for measuring particle size> was extracted, and the average value was taken as the average circularity (area).

[0049] <Viscosity Measurement Method> The viscosity of the biomass-containing fuels obtained in Examples 3 to 11 was measured at 25° C. and 5 rpm using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd., TV-100, rotor #1).

[0050] <Evaluation of Fuel Ignition and Combustion> Using a combustion test device (FIA100) conforming to the IP541 / 06 combustion characteristics test method, high-temperature, high-pressure (20 bar, 450°C) air was generated in a fixed-volume combustion chamber, simulating the combustion chamber of a diesel engine. The test fuel was injected and burned therein. The test was conducted to obtain combustion information (e.g., ignition delay time, main combustion delay, maximum heat release position, end of main combustion, end of combustion, main combustion period, total combustion period, heat release rate, total heat release value, estimated cetane number) from the pressure change in the combustion chamber. The estimated cetane number was calculated using a calibration curve prepared in advance using two standard fuels with known cetane numbers. To ensure uniform spray characteristics, the fuel sample was heated to a kinematic viscosity of approximately 20 cSt and used for measurement. Ten injections and combustions were performed to obtain data. Table 1 lists the main combustion period, total combustion period, average estimated cetane number, and standard deviation of ignition delay time.

[0051] Example 1 Cedar was crushed to 15 mm or less and dried to a moisture content of 15% or less. The chips were steamed at 1.5 revolutions per minute, an internal temperature of 400 °C, and atmospheric pressure using a rotary kiln with a barrel length of 3.5 m, an inclination angle of 4 degrees, and an internal baffle plate. The operation was adjusted so that it took approximately 30 minutes from loading to discharge, and cedar charcoal was obtained. The obtained charcoal was coarsely crushed using a commercially available hammer mill (manufactured by LabNext, RT-34), and then a commercially available fine grinder was used to obtain a charcoal powder with an average particle size of 5 μm. Kerosene was charged into a kettle, and a small amount of nitrogen was continuously introduced into the kettle under stirring. The charcoal crushed to an average particle size of 5 μm was slowly added in an amount to achieve a concentration of 30%, and after addition, the mixture was stirred for another hour. After stirring, the mixture was filtered through a 200-mesh wire mesh to obtain a cedar BOM (Biomass Oil Mixture). A fuel ignition and flammability test was carried out on a composition (biomass-containing fuel, 15% char) obtained by adding 100 g of diesel fuel to 100 g of cedar BOM. The results are shown in Table 1.

[0052] Example 2: A carbonized pulverized product with an average particle size of 5 μm was obtained in the same manner as in Example 1, except that bagasse was used as the plant biomass, and then a bagasse BOM was obtained in the same manner as in Example 1. 50 g of diesel fuel was added to 100 g of the bagasse BOM to obtain a composition (biomass-containing fuel, 20% char), and a fuel ignition and flammability test was performed on the composition. The results are shown in Table 1.

[0053] Example 3: Heavy oil A was charged into a kettle, and while stirring, a small amount of nitrogen was continuously introduced into the kettle. Cedar charcoal crushed to an average particle size of 5 μm was slowly added in an amount to achieve a 30% concentration, and the mixture was stirred for another hour. After stirring, the mixture was filtered through a 200-mesh wire screen to obtain a cedar BOM (Biomass Oil Mixture). The viscosity was 335 mPa·s. A fuel ignition and flammability test was conducted using this mixture. The results are shown in Table 1.

[0054] Example 4: Heavy oil A was charged into a kettle, and while stirring, a small amount of nitrogen was continuously introduced into the kettle. Carbonized bagasse pulverized to an average particle size of 5 μm was slowly added in an amount to achieve a 30% concentration, and the mixture was stirred for an additional hour. After stirring, the mixture was filtered through a 200-mesh wire screen to obtain a bagasse BOM (Biomass Oil Mixture). The viscosity was 556 mPa·s. This was used to conduct a fuel ignition and flammability test. The results are shown in Table 1.

[0055]

[0056] Both cedar BOM and bagasse BOM had good fuel stability, did not separate in the tank during the test period, and were confirmed to have combustion properties equivalent to heavy oil A. In addition, the standard deviation of ignition delay time was small, suggesting that they are also suitable for operation in multi-cylinder engines.

[0057] <Examples 5 to 10> In the same manner as in Example 1, cedar carbonized material was coarsely pulverized using a commercially available hammer mill (RT-34, manufactured by LabNext Co., Ltd.), and then a Pulvis PV-150 (manufactured by Hosokawa Micron Corporation) was used as a fine pulverizer, operating under the following conditions within the following ranges, to obtain pulverized carbonized material with the particle sizes listed in Table 2. The circularity (area) of the pulverized carbonized material with each particle size was as shown in Table 2. A cedar BOM was prepared in the same manner as in Example 1, except that the obtained pulverized carbonized material was used, and the viscosity was measured. The results are shown in Table 2. <Operating conditions for Pulvis PV-150> Media: 4.5 kg of 3 mm stainless steel beads used Raw material feeding rate: 5 to 20 g / min Pulverizer rotation speed: 300 to 600 rpm Classifier rotation speed: 4000 to 23000 rpm Bottom gas flow rate: 0.1 to 0.4 Nm ３ / min

[0058] Example 11 In the same manner as in Example 1, cedar carbonized material was coarsely pulverized using a commercially available hammer mill (RT-34, manufactured by LabNext Co., Ltd.), and then classified using a sieve with 20 μm openings to obtain a carbonized pulverized material with a particle size of 20.2 μm. The circularity (area) of the obtained carbonized pulverized material was as shown in Table 2. A cedar BOM was prepared in the same manner as in Example 1, except that the obtained carbonized pulverized material was used, and viscosity was measured. The results are shown in Table 2.

[0059]

Claims

1. A biomass-containing fuel that includes carbonized plant biomass and fuel oil.

2. The biomass-containing fuel according to claim 1, wherein the carbonization temperature of the carbonized plant biomass is 250 to 450°C.

3. The biomass-containing fuel according to claim 1 or 2, wherein the carbonized plant biomass has an average value of 0.5 or more and 1 or less for particles whose circularity (area) falls within ±10% of the average particle diameter (volume basis) measured by dynamic light scattering.

4. The biomass-containing fuel according to claim 1 or 2, wherein the carbonized plant biomass has a particle size of 50 μm or less, with a proportion of 95% or more.

5. The biomass-containing fuel according to claim 1 or 2, wherein the carbonized plant biomass has an average particle size of 0.1 μm or more and 20 μm or less.

6. The biomass-containing fuel according to claim 1 or 2, wherein the content ratio of the carbonized plant biomass is 10 to 60% by mass relative to 100% by mass of the biomass-containing fuel.

7. The biomass-containing fuel according to claim 1 or 2, wherein the biomass-containing fuel has a viscosity of 1000 mPa·s or less.

8. A method for producing biomass-containing fuel, comprising the steps of: carbonizing plant biomass by steaming; crushing the carbonized material obtained in the carbonization step; and mixing the crushed material obtained in the crushing step with fuel oil.