Composition for forming solid fuel

Abstract

This composition for forming a solid fuel comprises: a granular base material which is a carbide obtained by carbonizing organic matter; a self-curable resin; and a curing catalyst. The total content of the self-curable resin and the curing catalyst may be 0.1-150 parts by mass per 100 parts by mass of the base material. The content of the curing catalyst may be 0.1-50 parts by mass per 100 parts by mass of the base material. The self-curable resin may be at least one resin selected from the group consisting of resol-type phenolic resins and furan resins.

Description

Composition for forming solid fuel

[0001] The present invention relates to a composition for forming solid fuel. This application claims priority to Japanese Patent Application No. 2025-004617 filed in Japan on January 14, 2025, and incorporates the content thereof herein.

[0002] Conventionally, solid fuels obtained by carbonizing briquettes by dry distillation have been used in cupolas, blast furnaces, etc. Briquettes are generally produced by a method of mixing carbides such as coal with other raw materials and molding the resulting mixture.

[0003] Patent Document 1 discloses a method for producing briquettes in which a mixture containing 1 to 15 parts by mass of a thermoplastic plastic with respect to 100 parts by mass of coal powder is kneaded under temperature conditions of 170°C to 210°C, and then compressed and molded. Patent Document 2 discloses a method for producing formed coke in which a mixture containing coal and a thermosetting composition is prepared and the briquettes obtained by molding the mixture are subjected to dry distillation. Patent Document 3 discloses a method for producing coke in which brown coal and plant-derived biomass are mixed to obtain a mixture, and the mixture is hot-molded and carbonized.

[0004] Japanese Patent Application Laid-Open No. 10-306288, Patent No. 5705362, Japanese Patent Application Laid-Open No. 2019-199567

[0005] However, the conventional method for producing briquettes requires high temperature and high pressure for the molding conditions of the mixture, resulting in high energy costs.

[0006] An object of the present invention is to provide a composition for forming solid fuel that can produce solid fuel at a lower energy cost than conventional methods.

[0007] The present invention has the following embodiments: [1] A solid fuel molding composition comprising a granular base material which is a carbonized organic material, a self-hardening resin, and a curing catalyst. [2] The solid fuel molding composition according to [1], wherein the total content of the self-hardening resin and the curing catalyst is 0.1 to 150 parts by mass per 100 parts by mass of the base material. [3] The solid fuel molding composition according to [1] or [2], wherein the content of the curing catalyst is 0.1 to 50 parts by mass per 100 parts by mass of the base material. [4] The solid fuel molding composition according to any one of [1] to [3], wherein the self-hardening resin is at least one selected from the group consisting of resol-type phenolic resins and furan resins. [5] The solid fuel molding composition according to any one of [1] to [4], wherein the self-hardening resin contains a resol-type phenolic resin and the curing catalyst contains an organic acid ester. [6] The solid fuel molding composition according to [5], wherein the content of the organic acid ester is 1 to 50 parts by mass per 100 parts by mass of the base material. [7] The solid fuel molding composition according to any one of [1] to [6], wherein the self-hardening resin contains a furan resin and the curing catalyst contains an acid catalyst. [8] The solid fuel molding composition according to [7], wherein the content of the acid catalyst is 0.1 to 10 parts by mass per 100 parts by mass of the base material. [9] The solid fuel molding composition according to any one of [1] to [8], further comprising a liquid diluent at 25°C.

[10] The solid fuel molding composition according to any one of [1] to [9], wherein the organic matter is biomass.

[0008] According to the present invention, a solid fuel molding composition can be provided that enables the production of solid fuel at a lower energy cost than conventional methods.

[0009] In this specification, room temperature is defined as 10 to 40°C, more specifically 15 to 30°C, and more particularly 20 to 25°C. pH is the value at 25°C unless otherwise specified. Viscosity is the value measured by an E-type viscometer at 25°C. The weight-average molecular weight (hereinafter also referred to as "Mw") of the resin (resol-type phenolic resin, furan resin, etc.) is the polystyrene equivalent value measured by gel permeation chromatography (hereinafter also referred to as "GPC"). Solid content is non-volatile content (hereinafter also referred to as "NV"). NV is the residue after heating the sample at 135°C for 1 hour. The specific method for measuring NV is described in the examples below.

[0010] [Composition for Molding Solid Fuel] The composition for molding solid fuel of this embodiment (hereinafter also simply referred to as "the composition") comprises a granular base material, a self-hardening resin, and a curing catalyst. The composition of this embodiment may further contain other components. Hereinafter, the mixture of the self-hardening resin and the curing catalyst will also be referred to as "the binder." The binder exhibits self-hardening properties.

[0011] <Base Material> The base material is a carbonized material made from carbonized organic matter. There are no particular restrictions on the organic matter, and examples include biomass or fossil fuels. Among these, CO ２ Biomass is preferred from the standpoint of reducing emissions and realizing a sustainable society. Examples of biomass include seed and nut shells, bamboo, wood, herbaceous plants, seeds and nuts, grains, plant residues, food waste, wood product waste, livestock excrement, waste paper, pulp mill wastewater, or sewage sludge. Examples of seed and nut shells include coconut shells, cashew nut shells, walnut shells, almond shells, pistachio shells, sunflower seed shells, peanut shells, chestnut shells, shiitake mushroom shells, ginkgo nut shells, or rice husks. Among these, coconut shells or wood are preferred from the standpoint of price and supply. Organic matter may be used individually or in combination of two or more types.

[0012] The average particle size of the substrate may be, for example, 1 to 10,000 μm, preferably 50 to 8,000 μm, more preferably 50 to 5,000 μm, and even more preferably 1,000 to 3,000 μm. If the average particle size is above the lower limit, it mixes more uniformly with the self-hardening resin, and the moldability of the composition is better. If the average particle size is below the upper limit, the density and compressive strength of the molded product tend to be higher. The average particle size of the substrate is the volume average diameter measured by a particle size analyzer using a wet method. More specifically, the average particle size of the substrate refers to the volume-based cumulative 50% diameter (D50) measured by a wet method using a laser diffraction / scattering particle size analyzer (Microtrac-Bell, model MT3300EXII). The average particle size of the substrate can be adjusted as appropriate by classification by crushing or sieving.

[0013] The base material may be a commercially available one, or one produced by carbonizing organic matter. Carbonization can be carried out by conventionally known methods. For example, a carbide can be obtained by heating organic matter in the presence of an inert gas. Examples of inert gases include gases that are substantially free of oxygen, such as nitrogen, helium, argon, hydrogen, carbon monoxide, or carbon dioxide. Heating during carbonization can be carried out using a multi-stage furnace, a rotary kiln, or a fluidized bed furnace. The heating temperature is preferably in the range of 480 to 1200°C, more preferably in the range of 520 to 1000°C, and even more preferably in the range of 600 to 900°C.

[0014] <Self-hardening resins> Self-hardening resins are resins that exhibit self-hardening properties in the presence of a curing catalyst. "Exhibiting self-hardening properties" means that they can be cured at room temperature.

[0015] Examples of self-hardening resins include resol-type phenolic resins, furan resins, resorcinol resins, urethane resins, epoxy resins, unsaturated polyester resins, or acrylic resins. One type of self-hardening resin may be used alone, or two or more types may be used in combination. As for the self-hardening resin, at least one selected from the group consisting of resol-type phenolic resins and furan resins is preferred due to its high heat resistance and high fixed carbon content. A high fixed carbon content indicates a large amount of carbon that can be supported.

[0016] (Resol-type phenolic resins) Resol-type phenolic resins, also known as alkaline phenolic resins, typically contain addition condensates of phenols with aldehydes (phenolic condensates), an alkaline substance, and water. At least a portion of the alkaline substance is usually an alkaline catalyst used in the production of resol-type phenolic resins. The alkaline catalyst may be neutralized.

[0017] The pH of the resol-type phenolic resin is preferably 7 to 14, more preferably 8 to 14, and even more preferably 10 to 14. If the pH is above the lower limit, the organic acid ester will hydrolyze more easily when mixed with the organic acid ester described later, and the curing acceleration effect of the organic acid ester will be more easily obtained. If the pH is below the upper limit, the curing acceleration effect of the organic acid produced by the hydrolysis of the organic acid ester will be more easily obtained. The pH of the resol-type phenolic resin shall be the value measured by the glass electrode method in accordance with JIS Z 8802:2011. The sample used shall be an aqueous solution of 20 to 80% by mass of resol-type phenolic resin.

[0018] The weight-average molecular weight (Mw) of the resol-type phenolic resin is preferably 300 to 20,000, more preferably 500 to 15,000, even more preferably 800 to 10,000, particularly preferably 900 to 8,000, and most preferably 1,000 to 6,000. When the weight-average molecular weight of the resol-type phenolic resin is above the lower limit, there is a tendency for the amount of unreacted monomer components to decrease, and the odor when using the resin to be reduced. When it is below the upper limit, the viscosity tends to be lower, and it tends to be easier to mix with the substrate.

[0019] The viscosity of the resol-type phenolic resin is preferably 10 to 100,000 mPa·s, more preferably 10 to 50,000 mPa·s, even more preferably 15 to 20,000 mPa·s, particularly preferably 15 to 15,000 mPa·s, and most preferably 20 to 10,000 mPa·s. If the viscosity of the resol-type phenolic resin is above the lower limit, it adheres easily to the substrates. If it is below the upper limit, it mixes easily with the substrates.

[0020] The solid content of the resol-type phenolic resin is preferably 20 to 80% by mass, more preferably 30 to 70% by mass, even more preferably 40 to 60% by mass, and particularly preferably 40 to 50% by mass, based on the total mass of the resol-type phenolic resin. When the solid content is within the above range, it is easier to keep the viscosity of the resol-type phenolic resin within the preferred range described above.

[0021] Phenols are compounds having an aromatic ring and a hydroxyl group bonded to the aromatic ring. Phenols may be compounds known as monomers for phenolic resins, and examples include phenol, alkylphenols (o, m, and p cresols, o, m, and p ethylphenols, xylenol isomers, etc.), polyaromatic ring phenols (α and β naphthols, etc.), and polyhydric phenols (bisphenol A, bisphenol F, bisphenol S, pyrogallol, resorcinol, or catechol, hydroquinone, etc.). These phenols may be used individually or in combination of two or more. In terms of storage stability of resol-type phenolic resins, phenols other than resorcinol are preferred. Practical phenols other than resorcinol include phenol, o, m, and p cresols, or xylenol isomers.

[0022] Aldehydes are at least one compound selected from the group consisting of compounds having a formyl group and their polymers, such as formaldehyde, paraformaldehyde, acetaldehyde, propylaldehyde, benzaldehyde, salicylaldehyde, or glyoxal. These aldehydes may be used individually or in combination of two or more. Of these, formaldehyde or paraformaldehyde are practical substances. Formalin, an aqueous solution containing formaldehyde, may be used as formaldehyde.

[0023] The following combinations of phenols and aldehydes are preferred: Combination 1: Phenol and formaldehyde Combination 2: Phenol and formalin

[0024] As an alkaline catalyst, there are no particular restrictions as long as it can facilitate the addition-condensation reaction, and various alkaline substances can be used. Specific examples include inorganic alkaline substances such as hydroxides of alkali metals like sodium or potassium (sodium hydroxide or potassium hydroxide, etc.), oxides and hydroxides of alkaline earth metals like calcium, magnesium, or barium, sodium carbonate, or ammonia; organic alkaline substances such as tertiary amines like triethylamine and trimethylamine, cyclic amines like DBU (1,8-diazabicyclo[5.4.0]undec-7-ene), or DBN (1,5-diazabicyclo[4.3.0]nona-5-ene); and so on. The alkaline catalyst may be used alone or in combination of two or more types.

[0025] Examples of resol-type phenolic resins include those obtained by resolizing novolac-type phenolic resins (hereinafter also referred to as "phenolic resin (1)"). Specifically, phenolic resin (1) is a product of the reaction (secondary reaction, resol-type reaction) between a novolac-type phenolic resin and aldehydes in the presence of an alkaline catalyst, and is also called a secondary reaction resol-type phenolic resin. Compared to resol-type phenolic resins obtained by reacting phenols and aldehydes only in the presence of an alkaline catalyst, phenolic resin (1) tends to have superior curability in the presence of organic acid esters.

[0026] Novolac-type phenolic resins are the products of a reaction (first-order reaction, novolac-type reaction) between phenols and aldehydes in the presence of an acid catalyst. Novolac-type phenolic resins contain phenolic condensates in which the aromatic rings of two or more phenols are linked via methylene groups derived from aldehydes. In the second-order reaction, aldehydes are added to the aromatic rings of the phenolic condensates to generate methylol groups, and some of these methylol groups react with other phenolic condensates to increase their molecular weight. Therefore, phenolic resin (1) contains phenolic condensates that have methylol groups and have a higher molecular weight than the phenolic condensates contained in novolac-type phenolic resins.

[0027] The acid catalyst used in the first reaction is not particularly limited as long as it allows the first reaction to proceed. Examples include inorganic acids such as hydrochloric acid, sulfuric acid, and phosphoric acid; organic acids such as oxalic acid, acetic acid, citric acid, tartaric acid, benzoic acid, or p-toluenesulfonic acid; and organic acid salts such as zinc acetate or zinc borate. These acid catalysts may be used individually or in combination of two or more.

[0028] The amount of acid catalyst used is preferably 0.05 to 2.0 parts by mass, and more preferably 0.1 to 1.0 parts by mass, per 100 parts by mass of phenols. If the amount of acid catalyst used is above the lower limit, a sufficient reaction rate can be obtained. If it is below the upper limit, the reaction can be easily controlled. In this specification, the preferred upper and lower limits can be combined as appropriate. For example, the amount of acid catalyst used may be 0.05 to 1.0 parts by mass, or 0.1 to 1.0 parts by mass, per 100 parts by mass of phenols.

[0029] The molar ratio of aldehydes to phenols in novolac-type phenolic resins (hereinafter also referred to as the "F / P molar ratio") is preferably 0.6 to 0.9, and more preferably 0.7 to 0.8. If the F / P molar ratio in novolac-type phenolic resins is above the lower limit, the amount of aldehydes during the resolization reaction (secondary reaction) can be reduced, and the heat generated during the reaction can be suppressed. If it is below the upper limit, gelation during the novolac reaction (primary reaction) can be suppressed. In the case where novolac-type phenolic resins are obtained by the reaction of phenol with paraformaldehyde or formalin, the F / P molar ratio (formaldehyde / phenol) is preferably 0.6 to 0.9, and more preferably 0.7 to 0.8.

[0030] The Mw of the novolac-type phenolic resin is preferably 1000 to 8000, and more preferably 1500 to 6000. When the Mw of the novolac-type phenolic resin is within the above range, the Mw of the phenolic resin (1) tends to fall within the preferred range.

[0031] Examples of alkali catalysts used in the secondary reaction include those described above. The preferred amount of alkali catalyst used is determined by the molar ratio of alkali catalyst to phenols (hereinafter also referred to as the "alkali / P molar ratio"). The alkali / P molar ratio is preferably 0.1 to 1.0, more preferably 0.2 to 0.9, and even more preferably 0.5 to 0.8. If the alkali / P molar ratio is above the lower limit, the phenol resin (1) can be obtained quickly. If it is below the upper limit, the secondary reaction is easier to control.

[0032] The F / P molar ratio in the phenolic resin (1) is preferably 2.0 to 2.8, more preferably 2.0 to 2.6, and even more preferably 2.0 to 2.4. Here, the F / P molar ratio in the phenolic resin (1) is the molar ratio of the total amount of aldehydes used in the primary and secondary reactions to the phenols used in the primary reaction. Hereinafter, this molar ratio will also be referred to as the "final F / P molar ratio". If the final F / P molar ratio is above the lower limit, a sufficient amount of methylol groups is present in the phenolic resin (1), allowing for stronger adhesion between the substrates. If the final F / P molar ratio is below the upper limit, the amount of free aldehydes volatilized during the manufacture of the molded product and the amount of formaldehyde emitted from the molded product will be reduced. Free aldehydes are unreacted aldehydes. Paraformaldehyde or formalin are preferred as the aldehydes used in the secondary reaction.

[0033] At least a portion of the alkaline substance contained in the phenolic resin (1) is typically an alkaline catalyst used in the secondary reaction. Some of the alkaline substance may also be added after the secondary reaction.

[0034] The molar ratio of alkaline substance to phenols in phenol resin (1) is preferably 0.1 to 1.0, more preferably 0.2 to 0.9, and even more preferably 0.5 to 0.8. Here, the molar ratio of alkaline substance to phenols in phenol resin (1) is the molar ratio of the total amount of alkaline catalyst used in the secondary reaction and the total amount of alkaline substance added after the secondary reaction to the total amount of phenols used in the primary reaction. Hereinafter, this molar ratio will also be referred to as the "final alkaline substance / phenol molar ratio". If no alkaline substance is added after the secondary reaction, the total amount of alkaline catalyst used in the secondary reaction and the total amount of alkaline substance added after the secondary reaction is the amount of alkaline catalyst used in the secondary reaction. If the final molar ratio of alkaline substance to phenols is above the lower limit above, the amount of free aldehydes in phenol resin (1) can be reduced without significantly increasing the molecular weight (without increasing viscosity). If it is below the upper limit above, a sufficient reaction rate can be obtained and it is easy to control.

[0035] The phenolic resin (1) can be manufactured, for example, by the method described in Japanese Patent Application Publication No. 2018-53131.

[0036] As the resol-type phenolic resin, a reaction product of phenols and aldehydes in the presence of an alkaline catalyst (hereinafter also referred to as "phenolic resin (2)") may be used. Phenolic resin (2) is obtained by reacting phenols and aldehydes only in the presence of an alkaline catalyst. The phenols, aldehydes, and alkaline catalyst are the same as described above. The production of this reaction product can be carried out by known methods.

[0037] The preferred amount of alkaline catalyst used when reacting phenols and aldehydes in the presence of an alkaline catalyst is determined by the molar ratio of the alkaline catalyst to the phenols (hereinafter also referred to as the "alkali / P molar ratio"). The alkali / P molar ratio is preferably 0.1 to 1.0, more preferably 0.2 to 0.9, and even more preferably 0.5 to 0.8. If the alkali / P molar ratio is above the lower limit, the phenol resin (2) can be obtained quickly. If it is below the upper limit, the resol reaction is easier to control.

[0038] The F / P molar ratio in the phenolic resin (2) is preferably 1.5 to 3.5, more preferably 2.0 to 3.0, and even more preferably 2.0 to 2.4. When the F / P molar ratio is above the lower limit, a sufficient amount of methylol groups are present in the phenolic resin (2), allowing for stronger adhesion between the substrates. When the F / P molar ratio is below the upper limit, the amount of free aldehydes volatilized during the manufacturing of the molded product and the amount of formaldehyde emitted from the molded product are reduced.

[0039] (Furan Resins) Furan resins can be obtained by polymerizing a monomer composition containing a furan ring-containing monomer. The monomer composition may further contain other monomers besides the furan ring-containing monomer. The furan ring-containing monomer may be one known monomer for furan resins, such as furfuryl alcohol, furfural, or hydroxymethylfurfural. The furan ring-containing monomer may be used alone or in combination of two or more. The other monomers may be copolymerizable (cocondensed) with the furan ring-containing monomer, such as aldehydes, ketones, phenols, bisphenols, or urea. The phenols and aldehydes may be the same as those listed in the description of resol-type phenol resins. The other monomers may be used alone or in combination of two or more.

[0040] One polymerization method involves reacting a monomer composition in the presence of an acid catalyst. This causes the monomers to polymerize (condense), yielding a reaction product containing the condensate. The acid catalyst can be the same as the one used in the first reaction described above. The reaction product can be used directly as a furan resin, but it may also be partially neutralized with an alkaline substance. The alkaline substance can be the same as the alkaline catalyst used in the resol-type phenolic resin described above.

[0041] The viscosity of the furan resin is preferably 10 to 100,000 mPa·s, more preferably 10 to 50,000 mPa·s, still more preferably 15 to 20,000 mPa·s, particularly preferably 15 to 15,000 mPa·s, and most preferably 20 to 10,000 mPa·s. When the viscosity of the furan resin is at least the above lower limit value, it is easy to adhere the base materials to each other. When it is at most the above upper limit value, it is easy to mix uniformly with the base material.

[0042] The content of the solid component of the furan resin is preferably 30 to 100% by mass, more preferably 40 to 95% by mass, still more preferably 50 to 90% by mass, based on the total mass of the furan resin. When the content of the solid component is within the above range, it is easy to make the viscosity of the furan resin within the above preferred range.

[0043] The weight average molecular weight (Mw) of the furan resin is preferably 300 to 20,000, more preferably 500 to 10,000, still more preferably 500 to 5,000, particularly preferably 600 to 3,000, and most preferably 800 to 2,000. When the weight average molecular weight of the furan resin is at least the above lower limit value, the residual amount of unreacted monomers tends to be small and the yield is more excellent. When it is at most the above upper limit value, the viscosity tends to be low and it becomes easy to mix with the base material.

[0044] <Curing Catalyst> A known curing catalyst can be used according to the type of the self-curing resin.

[0045] When the self-hardening resin contains a resol type phenol resin, the curing catalyst preferably contains an organic acid ester. The organic acid ester may be solid or used as a gas. Examples of the organic acid ester include carbonic acid esters such as ethylene carbonate, propylene carbonate, or dimethyl carbonate; lactones such as γ-butyrolactone, α-acetolactone, or β-propiolactone; monocarboxylic acid esters such as triacetin, ethylene glycol diacetate, triethylene glycol diacetate, ethyl acetate, methyl butyrate, ethyl butyrate, ethyl formate, methyl formate, methyl salicylate, or ethyl acetoacetate; and dicarboxylic acid monoesters or dicarboxylic acid diesters such as dimethyl succinate, diethyl succinate, dimethyl adipate, diethyl adipate, dimethyl glutarate, diethyl glutarate, or diethyl malonate. These organic acid esters may be used alone or in combination of two or more.

[0046] Among these, as the organic acid ester, at least one selected from the group consisting of carbonic acid esters, lactones, and carboxylic acid esters of polyols is preferable in that the gel time of the composition at room temperature, for example, 25 °C is short and the curability is more excellent, and at least one selected from the group consisting of ethylene carbonate, propylene carbonate, dimethyl carbonate, γ-butyrolactone, α-acetolactone, β-propiolactone, triacetin, and ethylene glycol diacetate is more preferable. Among these, at least one selected from the group consisting of propylene carbonate, γ-butyrolactone, triacetin, and ethylene glycol diacetate is preferable in that the curing acceleration effect can be obtained in a smaller amount. If necessary, organic acid esters other than these may be used in combination.

[0047] When the self-hardening resin contains a furan resin, the curing catalyst preferably contains an acid catalyst. Examples of acid catalysts include inorganic acids such as sulfuric acid, phosphoric acid, and hydrochloric acid; organic acids such as organic sulfonic acids or carboxylic acids. Organic sulfonic acids are organic compounds in which a sulfo group is substituted on a carbon skeleton. Examples of organic sulfonic acids include xylene sulfonic acid, p-toluenesulfonic acid, benzenesulfonic acid, methanesulfonic acid, and phenolsulfonic acid. These sulfonic acids may be used individually or in combination of two or more. Examples of carboxylic acids include formic acid, acetic acid, oxalic acid, lactic acid, maleic acid, malic acid, citric acid, tartaric acid, malonic acid, succinic acid, or benzoic acid. These carboxylic acid-containing acids may be used individually or in combination of two or more.

[0048] As an acid catalyst, sulfonic acid compounds are preferred in terms of higher strength and heat resistance of the cured product, and among them, xylene sulfonic acid, p-toluenesulfonic acid, or phenolsulfonic acid are particularly preferred in terms of their excellent performance as a curing catalyst. As an acid catalyst, it is preferable to use at least an organic acid from the viewpoint of a longer pot life and further improvement of the strength of the cured product. Inorganic acids and organic acids may be used in combination as the acid catalyst. When inorganic acids and organic acids are used in combination, it is preferable to have a higher proportion of organic acids than inorganic acids.

[0049] The gelation time of the curing catalyst is preferably 0.5 to 30 minutes, more preferably 0.6 to 14 minutes, even more preferably 1 to 14 minutes, and particularly preferably 1 to 10 minutes. Within this range, the compressive strength of the molded product tends to improve. The gelation time of the curing catalyst can be measured by the method of the examples.

[0050] <Binding Agent> The viscosity of the binding agent is preferably 5 to 100,000 mPa·s, more preferably 10 to 50,000 mPa·s, even more preferably 10 to 20,000 mPa·s, particularly preferably 10 to 15,000 mPa·s, and most preferably 10 to 10,000 mPa·s. If the viscosity of the binding agent is above the lower limit, it is easier to bond the substrates together. If it is below the upper limit, it is easier to mix uniformly with the substrates.

[0051] The solid content of the binder is preferably 20 to 80% by mass, more preferably 30 to 75% by mass, and even more preferably 40 to 70% by mass, relative to the total mass of the binder. When the solid content is within the above range, it is easier to keep the viscosity of the binder within the preferred range described above.

[0052] <Other ingredients> Other ingredients include, for example, diluents and surfactants.

[0053] Diluents are used to dilute and reduce the viscosity of binders. Preferred diluents are those that are liquid at 25°C, such as furfural, furfuryl alcohol, cardanol, water, or solvents. Diluents may be used individually or in combination of two or more. When the self-hardening resin is a resol-type phenolic resin, water or methanol are preferred as diluents due to their high resin dilution properties and high viscosity reduction effect. When the self-hardening resin is a furan resin, furfuryl alcohol reacts with the furan resin during curing to form a cured product. When the self-hardening resin is a furan resin, furfural, furfuryl alcohol, cardanol, tetrahydrofuran, or acetone are preferred as diluents due to their high resin dilution properties and high viscosity reduction effect.

[0054] <Content of each component> In the composition, the content of the self-hardening resin is preferably 1 to 100 parts by mass, more preferably 1 to 50 parts by mass, even more preferably 1 to 25 parts by mass, and particularly preferably 2 to 20 parts by mass, per 100 parts by mass of the base material. When the content of the self-hardening resin is above the lower limit, the moldability at room temperature tends to be better. When the content of the self-hardening resin is below the upper limit, the stickiness of the base material tends to be reduced and the adhesion of the composition to manufacturing equipment tends to be suppressed.

[0055] The content of the curing catalyst is preferably 0.1 to 50 parts by mass per 100 parts by mass of the substrate. If the curing catalyst contains an organic acid ester, the content of the organic acid ester is preferably 1 to 50 parts by mass, more preferably 1 to 30 parts by mass, even more preferably 1 to 10 parts by mass, and even more preferably 1 to 5 parts by mass per 100 parts by mass of the substrate. If the curing catalyst contains an acid catalyst, the content of the acid catalyst is preferably 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, and even more preferably 0.3 to 5 parts by mass per 100 parts by mass of the substrate. When the content of the curing catalyst is above the lower limit, the curability and moldability at room temperature tend to be better. When the content of the curing catalyst is below the upper limit, the pot life can be sufficiently extended, and the control of the curing reaction tends to be better.

[0056] The binder content, i.e., the total content of the self-hardening resin and curing catalyst, is preferably 0.1 to 150 parts by mass, more preferably 0.1 to 100 parts by mass, even more preferably 1 to 50 parts by mass, and particularly preferably 1 to 25 parts by mass, per 100 parts by mass of the substrate. When the binder content is above the lower limit, the moldability at room temperature tends to be better. When the binder content is below the upper limit, the stickiness of the substrate tends to be reduced and the adhesion of the composition to manufacturing equipment tends to be suppressed.

[0057] The solid content of the binder is preferably 1 to 120 parts by mass, more preferably 1 to 100 parts by mass, even more preferably 1 to 50 parts by mass, and particularly preferably 5 to 25 parts by mass, per 100 parts by mass of the base material. When the solid content of the binder is above the lower limit, the moldability at room temperature tends to be better. When the solid content of the binder is below the upper limit, the stickiness of the base material tends to be reduced, and the adhesion of the composition to manufacturing equipment tends to be suppressed.

[0058] The total content of the base material and binder is, for example, 40% by mass or more, more precisely 60% by mass or more, more precisely 80% by mass or more, and may be 100% by mass, based on the total mass of the composition.

[0059] The diluent content is preferably 1 to 50 parts by mass, more preferably 1 to 30 parts by mass, even more preferably 1 to 20 parts by mass, and particularly preferably 1 to 10 parts by mass, per 100 parts by mass of the base material. If the diluent content is above the lower limit, the viscosity is reduced and the binder can be uniformly mixed into the base material. If the diluent content is below the upper limit, the solid content concentration of the binder is sufficiently high, which tends to result in superior strength of the cured product.

[0060] <Applications> The composition of this embodiment is for molding solid fuel. For example, a molded product obtained by compression molding the composition of this embodiment can be used as solid fuel. Compression molding can be carried out by known methods. For example, a molded product can be obtained by placing the composition in a mold and molding it under pressure.

[0061] The molding temperature is preferably 0 to 100°C, more preferably 0 to 60°C, and even more preferably 10 to 40°C. If the molding temperature is below the above upper limit, energy costs can be reduced compared to conventional methods. If the molding temperature is above the above lower limit, curability and moldability are further improved.

[0062] The molding pressure is preferably 1 to 100 MPa, more preferably 1 to 50 MPa, even more preferably 1 to 20 MPa, and particularly preferably 10 to 20 MPa. If the molding pressure is below the above upper limit, energy costs can be reduced compared to conventional methods. If the molding pressure is above the above lower limit, moldability is better. The molding pressure is a surface pressure.

[0063] The molding time is preferably 1 second to 10 minutes, more preferably 1 second to 5 minutes, and even more preferably 1 second to 3 minutes. If the molding time is below the above upper limit, energy costs can be reduced compared to conventional methods. If the molding time is above the above lower limit, the moldability is better. In another embodiment, the molding time is preferably 1 to 10 minutes, more preferably 2.5 to 10 minutes, and even more preferably 2.5 to 5 minutes. Within the above range, the compressive strength of the molded product tends to improve.

[0064] After molding, the molded product is removed from the mold. The molded product may be cured before or after removal from the mold. The curing temperature is preferably 0 to 60°C, more preferably 10 to 40°C. The curing time is preferably 0.1 to 100 hours, more preferably 0.1 to 50 hours, and even more preferably 0.1 to 24 hours. In another embodiment, the curing time is preferably 0.5 to 100 hours, more preferably 1 to 72 hours, and even more preferably 3 to 72 hours. If the curing time is above the lower limit of the above range, the compressive strength of the molded product tends to improve. The resulting molded product typically comprises a base material and a cured product of a self-hardening resin.

[0065] <Effects> The composition of this embodiment contains a self-hardening resin and a curing catalyst, and therefore exhibits self-hardening properties, making it moldable at room temperature, in a short time (e.g., 5 minutes or less), and at low pressure (e.g., 50 MPa or less). Molded products made from the composition of this embodiment can be used as a solid fuel substitute for coke in cupolas, blast furnaces, etc.

[0066] 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 "mass percent". "Parts" means "parts by mass".

[0067] <Evaluation Method> [Weight-average molecular weight (Mw)] ・Pretreatment: 2 g of resol-type phenol resin sample (resin) was diluted with 2 g of pure water and 10 g of THF (tetrahydrofuran). The pH was adjusted to 4.0 with 1 N hydrochloric acid aqueous solution while checking the pH. The THF layer and aqueous layer were separated, and the THF layer was diluted 5 times with THF to prepare the sample for GPC measurement. ・Pretreatment: 0.04 g of furan resin sample (resin) was diluted with 4 g of THF to prepare the sample for GPC measurement. ・GPC measurement The obtained GPC measurement samples were subjected to GPC measurement under the following measurement conditions, and the weight-average molecular weight in polystyrene equivalent was confirmed from the results. Column: TSKgel G3000HXL 7.8 × 300 mm × 1 tube (Tosoh Corporation), TSKgel G2000HXL 7.8 × 300 mm × 2 tubes (Tosoh Corporation). Column temperature: 40°C. Detector: RI (Differential Refractive Index Detector). Solvent: THF (Tetrahydrofuran). Flow rate: 0.8 mL / min.

[0068] [Solid Content (Non-Volatile Content)] Mass C of an aluminum foil dish (inner diameter 50 mm, height 15 mm) １ (g) was weighed. The sample was then accurately weighed to 1.5 ± 0.1 g. The specific mass of the sample was defined as the sample mass S (g) before drying. This aluminum foil dish was placed in a constant temperature oven preheated to 135 ± 1°C and dried for 60 ± 2 minutes. After that, it was allowed to cool in a desiccator, and its mass C was determined. ２ The amount (g) was measured. From the results, the mass D of the dried sample (mass of the sample remaining on the aluminum foil tray after drying) (g) was calculated using the following formula (1), and the non-volatile content (NV) in the sample (%) was calculated using the following formula (2). D = C ２ -C １ ... (1) Non-volatile content (NV) (%) = D / S × 100 ... (2)

[0069] [Viscosity] Viscosity was measured using an E-type viscometer at 25°C. Specifically, it was measured in accordance with JIS K 6910:2007, 5.3.2 Viscosity Method B. The temperature during measurement was 25°C.

[0070] [Shape] The shape of the molded product after compression molding and removal from the mold was evaluated according to the following criteria: ○: The molded product maintained the predetermined shape (cylindrical in this embodiment). ×: The molded product crumbled into powder and could not maintain the predetermined shape.

[0071] [Compressive Strength] The compressive strength of the molded product was measured using a Strograph (manufactured by Toyo Seiki Seisakusho Co., Ltd., model number: V50-C). The compression rate during measurement was 5 mm / min.

[0072] <Materials Used> [Resin] The resins used are shown in Table 1. A-1 to A-19 are synthetic products obtained in the synthesis examples described later. For A-20, PL-7737 manufactured by Gun-ei Chemical Industry Co., Ltd. was used. For A-21, PG-4875 manufactured by Gun-ei Chemical Industry Co., Ltd. was used.

[0073]

[0074] [Curing Catalyst] The curing catalysts used are shown in Table 2. In Table 2, GBL is γ-butyrolactone, EGDA is ethylene glycol diacetate, DBE is a dibasic acid ester, and 65% PSA is a 65% phenolsulfonic acid (PSA) aqueous solution. B-2 is a mixture of GBL and EGDA in a 5:5 (mass ratio). The dibasic acid ester is a mixture of dimethyl glutarate, dimethyl succinate, and dimethyl adipate in a 55-65:15-25:10-25 (mass ratio).

[0075] The gelation time (GT) for self-hardening resol-type phenolic resin curing catalysts B-1 to B-4 was measured using the following procedure. The results are shown in Table 2. 20 parts of B-1, B-2, B-3, or B-4 were added to 80 parts of A-8. The gelation time (GT) from the time of addition until gelation began at 25°C was measured.

[0076]

[0077] [Base Material] The base materials used are shown in Table 3.

[0078]

[0079] <Example of resin synthesis> [Synthesis of base resin] In a reaction apparatus equipped with a condenser, thermometer, and stirrer, 1466.0 parts of phenol, 748.8 parts of 50% formalin (F / P molar ratio: 0.80), 4.88 parts of 30% sulfuric acid, and 102.2 parts of water were charged and reacted under reflux conditions for 3 hours. After that, it was cooled to below 80°C, and 455.1 parts of 48% sodium hydroxide aqueous solution were added to obtain the base resin.

[0080] [Synthesis of A-1] 800.0 parts of base resin, 240.0 parts of 50% formalin (final F / P molar ratio: 1.8), and 32.7 parts of water were added. The mixture was reacted at 65°C until the viscosity reached 58,600 mPa·s, and then immediately cooled to below 50°C. Once the temperature was below 50°C, 131.1 parts of 48% sodium hydroxide aqueous solution and water were added to achieve a solid content concentration of 43.4% to obtain the self-hardening resol-type phenolic resin A-1.

[0081] [Synthesis of A-2] 750.0 parts of base resin, 312.0 parts of 50% formalin (final F / P molar ratio: 2.1), and 42.5 parts of water were added. The mixture was reacted at 65°C until the viscosity reached 29,070 mPa·s, and then immediately cooled to below 50°C. Once the temperature was below 50°C, 122.9 parts of 48% sodium hydroxide aqueous solution and water were added to achieve a solid content concentration of 44.0% to obtain the self-hardening resol-type phenolic resin A-2.

[0082] [Synthesis of A-3, A-4, A-5, A-6, A-7, A-8, A-9] 700.0 parts of base resin, 384.0 parts of 50% formalin (final F / P molar ratio: 2.4), and 52.4 parts of water were added. The mixture was reacted at 65°C for 0 minutes, 30 minutes, 1 hour, 2 hours, or 3 hours, and immediately cooled to below 50°C. Once the temperature was below 50°C, 114.7 parts of 48% sodium hydroxide aqueous solution and water were added to achieve a solid content concentration of 50.0% to obtain self-hardening resol-type phenolic resins A-3, A-4, A-5, A-7, or A-9. The above description indicates that A-3 was reacted for 0 minutes at 65°C, A-4 for 30 minutes, A-5 for 1 hour, A-7 for 2 hours, and A-9 for 3 hours. In the synthesis of A-7, the amount of water added was adjusted so that the solid content concentration was 44.2% or 52.0%, but otherwise the same procedure was followed to obtain self-hardening resol-type phenolic resins A-6 or A-8.

[0083] [Synthesis of A-10] 650.0 parts of base resin, 456.0 parts of 50% formalin (final F / P molar ratio: 2.7), and 62.2 parts of water were added. The mixture was reacted at 65°C until the viscosity reached 1,836 mPa·s, and then immediately cooled to below 50°C. Once the temperature was below 50°C, 106.5 parts of 48% sodium hydroxide aqueous solution and water were added to achieve a solid content concentration of 44.3% to obtain the self-hardening resol-type phenolic resin A-10.

[0084] [Synthesis of A-11] 600.0 parts of base resin, 528.0 parts of 50% formalin (final F / P molar ratio: 3.0), and 72.0 parts of water were added. The mixture was reacted at 65°C until the viscosity reached 751 mPa·s, and then immediately cooled to below 50°C. Once the temperature was below 50°C, 98.3 parts of 48% sodium hydroxide aqueous solution and water were added to achieve a solid content concentration of 44.1% to obtain the self-hardening resol-type phenolic resin A-11.

[0085] [Synthesis of A-12, A-13, A-14, A-15, and A-16] In a reaction apparatus equipped with a condenser, thermometer, and stirrer, 1000.0 parts of phenol, 1530.3 parts of 50% formalin (F / P molar ratio: 2.40), and 416.0 parts of 48% sodium hydroxide aqueous solution were charged and reacted at 66°C for 4 hours. Then the temperature was raised to 85°C and the reaction was continued for 4 hours. When the temperature fell below 50°C, 198.2 parts of 48% sodium hydroxide aqueous solution were added, and water was added to achieve solid content concentrations of 46.0%, 48.0%, 50.0%, 52.0%, or 56.7% to obtain self-hardening resol-type phenolic resins A-12, A-13, A-14, A-15, or A-16.

[0086] [Synthesis of A-17] In a reaction apparatus equipped with a condenser, thermometer, and stirrer, 350 parts of phenol, 506 parts of 44% formaldehyde aqueous solution (F / P molar ratio: 2.0), 71 parts of water, and 175 parts of 25% sodium hydroxide were charged. The reaction was carried out at 85°C for 120 minutes, and then at 67°C for 45 minutes. After that, the mixture was cooled to below 45°C, and 117 parts of 25% sodium hydroxide, 130 parts of potassium hydroxide, and 35 parts of water were added to obtain the self-hardening resol-type phenolic resin A-17.

[0087] [Synthesis of A-18] 3500 parts of furfuryl alcohol (FFA) and 1.26 parts of 50% p-toluenesulfonic acid were charged into a reactor equipped with a condenser, thermometer, and stirrer. After reacting at 80°C for 1 hour, the mixture was cooled to below 40°C and 1.33 parts of 48% sodium hydroxide aqueous solution were added. The mixture was then heated to 200°C under a vacuum of 680 mmHg to obtain the self-hardening furan resin A-18.

[0088] [Synthesis of A-19] 3500 parts of furfuryl alcohol (FFA) and 1.26 parts of 50% p-toluenesulfonic acid were charged into a reactor equipped with a condenser, thermometer, and stirrer. After reacting at 90°C for 3 hours, the mixture was cooled to below 40°C and 1.33 parts of 48% sodium hydroxide aqueous solution were added. The mixture was then heated to 200°C under a vacuum of 680 mmHg to obtain the self-hardening furan resin A-19.

[0089] <Test Example 1> [Preparation of Composition] 30 g of the substrate shown in Table 4 was accurately weighed, and the curing catalyst shown in Table 4 was added under conditions of 25°C and stirred for 30 seconds. Next, the resin shown in Table 4 was added and stirred for 60 seconds to obtain the composition. In Table 4, the amount of resin added (%), the amount of curing catalyst added (%), the amount of binder added (%), and the binder solids (%) are the ratios of resin, curing catalyst, binder, and binder solids, respectively, to 100% of the mass of the substrate. The binder is a mixture of resin and curing catalyst. The same applies to the test examples described later.

[0090] [Preparation of Molded Products] The obtained composition was placed in a mold. Compression molding was performed under the molding conditions (temperature, time, pressure) shown in Table 4 to obtain cylindrical molded products with a diameter of 50 mm and a height of 20 mm. The molding pressure was surface pressure. The obtained molded products were removed from the mold and their shape was evaluated. Next, after curing at 25°C for 24 hours, the density and compressive strength were measured. The results are shown in Table 4. However, for Comparative Examples 1 and 2, the molded products collapsed into powder when removed from the mold. Therefore, the density and compressive strength were not measured. Note that when the molding temperature was changed to 200°C, the shape was maintained when removed from the mold.

[0091]

[0092] The compositions of Examples 1 to 4 could be molded at room temperature, for a short time (5 minutes or less), and at low pressure (50 MPa or less). The compositions of Comparative Examples 1 and 2, which were not self-hardening, could not be molded under the same molding conditions as Examples 1 to 4.

[0093] <Test Example 2> The composition was prepared in the same manner as in Example 1, except that the resin and its amount added were changed as shown in Table 5. Molded products were then made, and their density and compressive strength were measured. The results are shown in Table 5.

[0094]

[0095] A comparison of Examples 5 to 9 showed that the compressive strength of the molded product was maximized when the F / P molar ratio of the self-hardening resol-type phenolic resin was 2.4.

[0096] <Test Example 3> The composition was prepared in the same manner as in Example 1, except that the resin and its amount added were changed as shown in Table 6. Molded products were then made, and their density and compressive strength were measured. The results are shown in Table 6.

[0097]

[0098] A comparison of Examples 10-14 showed that the difference in Mw of the self-hardening resol-type phenolic resins did not significantly affect the compressive strength of the molded product.

[0099] <Test Example 4> The composition was prepared in the same manner as in Example 2, except that the resin and its amount added were changed as shown in Table 7. Molded products were then made, and their density and compressive strength were measured. The results are shown in Table 7. The results from Example 2 are also shown.

[0100]

[0101] A comparison of Examples 2, 15-18 showed that when the NV of the self-hardening resol-type phenolic resin exceeded 52% (viscosity of 20,000 mPa·s or higher), there was a tendency for the compressive strength of the molded product to decrease.

[0102] <Test Example 5> The composition was prepared in the same manner as in Example 1, except that the type of curing catalyst was changed as shown in Table 8. Molded products were then made, and their density and compressive strength were measured. The results are shown in Table 8. The results from Example 1 are also shown.

[0103]

[0104] A comparison of Examples 1 and 20-21 showed that the higher the curing-accelerating effect of the curing catalyst (shorter GT as shown in Table 2), the greater the tendency for the compressive strength of the molded product to improve.

[0105] <Test Example 6> The composition was prepared in the same manner as in Example 1, except that the amount of curing catalyst added was changed as shown in Table 9. Molded products were then made, and their density and compressive strength were measured. The results are shown in Table 9. The results from Example 1 are also shown.

[0106]

[0107] A comparison of Examples 1, 22-23 showed that the compressive strength of the molded product was superior when the amount of curing catalyst added was 2 parts or more.

[0108] <Test Example 7> The composition was prepared in the same manner as in Example 1, except that the amounts of resin and curing catalyst added were changed as shown in Table 10. Molded articles were then produced, and their density and compressive strength were measured. The results are shown in Table 10. The results from Example 1 are also shown.

[0109]

[0110] A comparison of Examples 1, 24-25 showed that increasing the amount of binder (total of resin and curing catalyst) tended to improve the compressive strength of the molded product.

[0111] <Test Example 8> The composition was prepared and molded products were made in the same manner as in Example 1, except that the molding pressure was changed as shown in Table 11. The density and compressive strength were then measured. The results are shown in Table 11. The results from Example 1 are also shown.

[0112]

[0113] A comparison of Examples 1 and 26-27 showed that as the molding pressure increased, the compressive strength of the molded product tended to improve. In other words, when the molding pressure was 10 MPa or higher, the compressive strength of the molded product tended to improve.

[0114] <Test Example 9> The composition was prepared and molded products were made in the same manner as in Example 1, except that the molding time was changed as shown in Table 12. The density and compressive strength were then measured. The results are shown in Table 12. The results from Example 1 are also shown.

[0115]

[0116] A comparison of Examples 1, 28-30 showed that when the molding time was 2.5 minutes or longer, the compressive strength of the molded product tended to improve.

[0117] <Test Example 10> The composition was prepared and molded products were made in the same manner as in Example 1, except that the curing time was changed as shown in Table 13. The density and compressive strength were then measured. The results are shown in Table 13. The results from Example 1 are also shown.

[0118]

[0119] A comparison of Examples 1, 31-36 showed that when the curing time was 3 hours or more, the compressive strength of the molded product tended to stabilize.

[0120] <Test Example 11> The composition was prepared in the same manner as in Example 1, except that the type and amount of resin added, the amount of curing catalyst added, and the type of substrate were changed as shown in Tables 14 to 16. Molded products were then made, and their density and compressive strength were measured. The results are shown in Tables 14 to 16.

[0121]

[0122]

[0123]

[0124] When the average particle size of the substrate was relatively large, a higher viscosity resin tended to result in a better molded shape. This is thought to be because a higher viscosity resin makes it easier for the substrates to adhere to each other. When the average particle size of the substrate was relatively small, a lower viscosity resin tended to result in a better molded shape. This is thought to be because a lower viscosity resin allows for more uniform mixing of substrates with smaller average particle sizes.

[0125] <Test Example 12> [Preparation of Composition] 30 g of the base material shown in Table 17 was accurately weighed, and the curing catalyst shown in Table 17 was added under conditions of 25°C and stirred for 30 seconds. Next, the resin and additives shown in Table 17 were added and stirred and mixed for 60 seconds to obtain the composition.

[0126] [Preparation of Molded Products] The obtained composition was placed in a mold. Compression molding was performed under the molding conditions (temperature, time, pressure) shown in Table 17 to obtain cylindrical molded products with a diameter of 50 mm and a height of 20 mm. The molding pressure was surface pressure. The obtained molded products were removed from the mold and their shape was evaluated. Next, after curing at 25°C for 24 hours, the density and compressive strength were measured. The results are shown in Table 17.

[0127]

[0128] A comparison of Examples 47 to 51 showed that adding furfural to reduce the viscosity of the composition tended to improve moldability.

[0129] <Test Example 13> The composition was prepared in the same manner as in Example 50, except that the type of additive was changed as shown in Table 18. Molded products were then made, and their density and compressive strength were measured. The results are shown in Table 18. The results for Example 50 are also shown.

[0130]

[0131] A comparison of Examples 50 and 52-53 showed that there was no significant difference in the compressive strength of the molded product when the type of additive was changed.

[0132] <Test Example 14> The composition was prepared in the same manner as in Example 47, except that the amounts of resin and curing catalyst added were changed as shown in Table 19. Molded articles were then produced, and their density and compressive strength were measured. The results are shown in Table 19. The results for Example 47 are also shown.

[0133]

[0134] A comparison of Examples 47 and 54-55 showed that increasing the amount of binder (total of resin and curing catalyst) tended to improve the compressive strength of the molded product.

[0135] <Test Example 15> The composition was prepared in the same manner as in Example 47, except that the amount of curing catalyst added was changed as shown in Table 20. Molded products were then made, and their density and compressive strength were measured. The results are shown in Table 20. The results for Examples 4 and 47 are listed together.

[0136]

[0137] A comparison of Examples 4, 47, and 56-58 showed that the compressive strength of the molded product tended to improve as the amount of curing catalyst added increased.

Claims

1. A solid fuel molding composition comprising a granular base material which is a carbonized organic material, a self-hardening resin, and a curing catalyst.

2. The solid fuel molding composition according to claim 1, wherein the total content of the self-hardening resin and the curing catalyst is 0.1 to 150 parts by mass per 100 parts by mass of the substrate.

3. The solid fuel molding composition according to claim 1 or 2, wherein the content of the curing catalyst is 0.1 to 50 parts by mass per 100 parts by mass of the substrate.

4. The solid fuel molding composition according to claim 1 or 2, wherein the self-hardening resin is at least one selected from the group consisting of resol-type phenolic resins and furan resins.

5. The solid fuel molding composition according to claim 1 or 2, wherein the self-hardening resin comprises a resol-type phenolic resin and the curing catalyst comprises an organic acid ester.

6. The solid fuel molding composition according to claim 5, wherein the content of the organic acid ester is 1 to 50 parts by mass per 100 parts by mass of the base material.

7. The solid fuel molding composition according to claim 1 or 2, wherein the self-hardening resin comprises a furan resin and the curing catalyst comprises an acid catalyst.

8. The solid fuel molding composition according to claim 7, wherein the content of the acid catalyst is 0.1 to 10 parts by mass per 100 parts by mass of the base material.

9. The solid fuel molding composition according to claim 1 or 2, further comprising a liquid diluent at 25°C.

10. The solid fuel molding composition according to claim 1 or 2, wherein the organic matter is biomass.

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