Bioethanol raw material and method for producing same, and method for producing bioethanol

Abstract

Provided is a technique by which it becomes possible to produce a high-purity bioethanol raw material from waste paper that contains a metal or an organic material layer other than paper. The bioethanol raw material is derived from waste paper that contains at least one of a metal and an organic material layer other than paper, wherein the total content ratio of cellulose and hemicellulose in solid content is in the range of 90.0 to 99.5 mass%, the content ratio of organic materials excluding the cellulose, the hemicellulose and lignin in the solid content is in the range of 0.25 to 5.0 mass%, and the ash content ratio in the solid content is in the range of 0.25 to 5.0 mass%.

Description

Bioethanol raw material, its production method, and bioethanol production method

[0001] The present invention relates to the production of bioethanol.

[0002] With growing awareness of preventing global warming and building a recycling-oriented society, demand for bioethanol is on the rise. Bioethanol is made from organic compounds produced by photosynthetic organisms that absorb carbon dioxide from the atmosphere. Therefore, the carbon dioxide produced by burning bioethanol is considered to be carbon dioxide absorbed from the atmosphere by photosynthetic organisms during their growth process.

[0003] Bioethanol can be produced from, for example, corn or sugarcane. However, these are also useful as animal feed or food. Therefore, the use of waste paper and the like for the production of bioethanol has been investigated.

[0004] When producing bioethanol from woody biomass, monosaccharides are first produced from the woody biomass, and then these monosaccharides are fermented to produce ethanol. Monosaccharides can be produced by direct acid saccharification, which uses sulfuric acid for hydrolysis, or by enzymatic saccharification, which uses enzymes for hydrolysis. The enzymatic saccharification method has the advantages of low environmental impact and a high monosaccharide recovery rate.

[0005] In addition to cellulose and hemicellulose as its main components, waste paper contains various impurities. When using enzymatic saccharification to produce bioethanol from waste paper, these impurities can inhibit the enzymatic saccharification reaction.

[0006] For example, recycled paper contains organic matter as impurities, such as polyethylene film or resins such as rubber attached to one or both sides of the paper, or microcapsules or color developers added, for the purpose of imparting functions such as water resistance, pressure adhesion, or duplication. The organic matter contained in recycled paper inhibits the saccharification reaction by enzymes.

[0007] Patent Document 1 describes a method in which cellulose-containing waste, including a laminate of paper and a resin film, is immersed in an alkaline aqueous solution in advance, thereby allowing enzymes to sufficiently penetrate into the cellulose fibers in the paper portion to which the resin film is attached, thereby improving the saccharification efficiency per raw material.

[0008] Calcium carbonate contained in waste paper also inhibits enzymatic saccharification reactions. Patent Document 2 describes a method in which carbon dioxide is blown into an aqueous slurry produced by pretreating waste paper to convert the calcium carbonate into water-soluble calcium bicarbonate, and then the calcium bicarbonate is removed from the biomass by solid-liquid separation.

[0009] Furthermore, Patent Document 3 describes a method in which waste paper, which is a cellulose-containing raw material, is subjected to a process used in deinking for producing recycled pulp from printed waste paper to reduce the ash content, and then a saccharification process is carried out using an enzyme.

[0010] Japanese Patent Publication No. 2013-208097 Japanese Patent Publication No. 2010-41923 Japanese Patent Publication No. 2010-279300

[0011] The present invention aims to provide a technology that enables the production of high-purity bioethanol raw material from waste paper that contains organic layers other than paper or metals.

[0012] According to one aspect of the present invention, there is provided a bioethanol raw material derived from waste paper containing at least one of an organic layer other than paper and metal, wherein the total proportion of cellulose and hemicellulose in the solid content is in the range of 90.0 to 99.5 mass%, the proportion of organic matter excluding the cellulose, hemicellulose, and lignin in the solid content is in the range of 0.25 to 5.0 mass%, and the proportion of ash in the solid content is in the range of 0.25 to 5.0 mass%.

[0013] According to another aspect of the present invention, there is provided a bioethanol raw material according to the above aspect, wherein the waste paper includes an organic layer other than the paper.

[0014] According to yet another aspect of the present invention, there is provided the bioethanol raw material according to any one of the above aspects, wherein the waste paper contains the metal.

[0015] According to yet another aspect of the present invention, there is provided the bioethanol raw material according to any one of the above aspects, wherein the proportion of metals in the ash is in the range of 10 to 40 mass %.

[0016] According to yet another aspect of the present invention, there is provided a method for producing bioethanol, comprising producing bioethanol from the bioethanol raw material according to any of the above aspects.

[0017] According to yet another aspect of the present invention, there is provided a method for producing a bioethanol raw material, the method comprising: carrying out a pretreatment step of applying shear force to waste paper or shredded waste paper containing paper and at least one of a non-paper organic layer and a metal in the presence of water so that the solids concentration is in the range of 10 to 40% by mass; and carrying out a purification step of washing with water the fibers contained in the mixture produced by the pretreatment step. Note that the fiber referred to here refers to one containing at least one of cellulose and hemicellulose.

[0018] According to yet another aspect of the present invention, there is provided the method according to the above aspect, wherein the waste paper contains an organic layer other than the paper.

[0019] According to yet another aspect of the present invention, there is provided the manufacturing method according to any one of the above aspects, wherein the waste paper contains the metal.

[0020] According to yet another aspect of the present invention, there is provided a manufacturing method according to any of the above aspects, wherein the waste paper has a total proportion of cellulose and hemicellulose in the range of 50 to 94 mass%, a proportion of organic matter excluding the cellulose, hemicellulose, and lignin in the range of 5.0 to 30.0 mass%, and an ash proportion in the range of 1.0 to 15.0 mass%.

[0021] Alternatively, according to yet another aspect of the present invention, there is provided a manufacturing method according to the above aspect, wherein the waste paper has an ash content in the range of 1 to 30 mass %, and the proportion of the residue remaining after removing cellulose, hemicellulose, lignin, and ash from the solids is in the range of 5 to 30 mass %.

[0022] According to yet another aspect of the present invention, there is provided the manufacturing method according to the above aspect, wherein the proportion of metals in the ash content of the waste paper is in the range of 2 to 40 mass %.

[0023] According to yet another aspect of the present invention, there is provided a manufacturing method according to any of the above aspects, wherein the shear force is applied to the waste paper or the shredded material by kneading.

[0024] According to yet another aspect of the present invention, there is provided the method according to the above aspect, wherein the kneading is carried out while the waste paper or the shredded material is heated with steam or hot water.

[0025] According to yet another aspect of the present invention, there is provided a manufacturing method according to any of the above aspects, wherein the pretreatment step further includes sequentially subjecting the waste paper or the shredded material to a maceration treatment and a dehydration treatment prior to applying the shear force to the waste paper or the shredded material.

[0026] According to yet another aspect of the present invention, there is provided a manufacturing method according to any of the above aspects, wherein the pretreatment step further includes crushing the waste paper to produce the shredded material prior to applying the shear force to the waste paper or the shredded material, and the shear force is applied to the shredded material.

[0027] According to yet another aspect of the present invention, there is provided a manufacturing method according to any of the above aspects, wherein the pretreatment step further includes supplying an agent that promotes disintegration to the waste paper or the shredded material prior to applying the shear force to the waste paper or the shredded material.

[0028] According to yet another aspect of the present invention, there is provided the method according to any of the preceding aspects, wherein washing the fibers with water includes diluting the mixture with water to obtain a cellulose solution, and centrifuging the cellulose solution to remove at least a portion of impurities from the cellulose solution.

[0029] According to yet another aspect of the present invention, there is provided the method according to any of the above aspects, wherein the purification step further comprises, prior to washing the fibers with water, diluting the mixture with water to obtain a diluted solution, and filtering the diluted solution to obtain a cellulose solution, and the washing of the fibers with water comprises centrifuging the cellulose solution to remove at least a portion of impurities from the cellulose solution.

[0030] According to yet another aspect of the present invention, there is provided the production method according to any one of the above aspects, further comprising dehydrating the cellulose solution from which at least a portion of the impurities have been removed.

[0031] According to yet another aspect of the present invention, there is provided a production method according to any of the above aspects for obtaining a bioethanol raw material in which the total proportion of cellulose and hemicellulose in the solid content is in the range of 90.0 to 99.5 mass%, the proportion of organic matter excluding cellulose, hemicellulose, and lignin in the solid content is in the range of 0.25 to 5.0 mass%, and the proportion of ash in the solid content is in the range of 0.25 to 5.0 mass%.

[0032] According to yet another aspect of the present invention, there is provided a production method according to the above aspect, in which a bioethanol raw material is obtained in which the proportion of metals in the ash is in the range of 10 to 40 mass %.

[0033] According to yet another aspect of the present invention, there is provided a method for producing bioethanol, the method including producing a bioethanol raw material by the production method according to any one of the above aspects, and producing bioethanol from the bioethanol raw material.

[0034] According to the present invention, a technology is provided that makes it possible to produce high-purity bioethanol raw material from waste paper that contains organic layers other than paper or metals.

[0035] Fig. 1 is a flowchart showing a method for producing bioethanol. Fig. 2 is a flowchart showing a method for producing a bioethanol raw material according to a first embodiment of the present invention. Fig. 3 is a flowchart showing a method for producing a bioethanol raw material according to a second embodiment of the present invention.

[0036] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments described below are more specific embodiments of any of the above aspects. The following items can be incorporated into each of the above aspects, either singly or in combination.

[0037] Furthermore, the embodiments shown below are merely examples of configurations for embodying the technical idea of ​​the present invention, and the technical idea of ​​the present invention is not limited to the specific examples below. Various modifications can be made to the technical idea of ​​the present invention within the technical scope defined by the claims.

[0038] <1> Method for Producing Bioethanol Fig. 1 is a flowchart showing a method for producing bioethanol. In the method shown in Fig. 1, a pretreatment step S1, a saccharification step S2, a fermentation step S3, and a distillation step S4 are carried out in this order.

[0039] The pretreatment step S1 is a step for producing a bioethanol raw material from biomass, in this case waste paper, suitable for subsequent processing, for example, enzymatic saccharification in the saccharification step S2. The production of this bioethanol raw material will be described later with reference to FIG. 2.

[0040] In the saccharification step S2, monosaccharides such as glucose are produced from the cellulose and hemicellulose contained in the bioethanol raw material by enzymatic saccharification to obtain a sugar solution. The enzymes used in the saccharification step S2 include cellulase. Cellulase is a group of enzymes having cellobiohydrolase activity, endoglucanase activity, and β-glucosidase activity. The enzymes used in the saccharification step S2 may further include hemicellulase. The saccharification step S2 is continued, for example, for several tens of minutes to several days while controlling the pH and temperature of the aqueous dispersion containing the bioethanol raw material and the enzyme so that the hydrolysis of cellulose and hemicellulose proceeds appropriately. In the saccharification step S2, fermentation by cellulase-producing bacteria may be used to produce monosaccharides.

[0041] In the fermentation step S3, ethanol fermentation is carried out using the monosaccharides contained in the sugar solution as a raw material to produce an ethanol-containing liquid. For the ethanol fermentation, yeast, bacteria having genes necessary for ethanol production by genetic modification, or both are used.

[0042] In the distillation step S4, the ethanol-containing liquid is distilled to separate it into ethanol and other components. In this way, bioethanol is obtained.

[0043] <2> Waste Paper <2.1> Waste Paper Containing an Organic Material Layer Other Than Paper One example of waste paper used as a starting material in the production of the bioethanol raw material described above is waste paper as a composite material containing paper and an organic material layer other than paper. This organic material layer other than paper (hereinafter simply referred to as the "organic material layer") may be any layer other than paper, as long as it contains organic material other than cellulose, hemicellulose, and lignin. The organic material layer may be a film or a coating. Examples of organic material layers include plastic films such as polyethylene and polyethylene terephthalate, films containing rubber such as natural rubber, printed layers, and coatings containing organic additives. Ink components used in the printed layer include pigments, resins, solvents, drying oils, acrylic acid oligomers, acrylic acid monomers, initiators, sensitizers, and adjuvants. The "organic additive" is an additive selected from compounds containing carbon atoms, and may be a low-molecular-weight compound, a high-molecular-weight compound, or an oligomer. The organic additive is, for example, a sizing material, a filler, a paper strength agent, a retention aid, a dye, a pigment, or an adhesive, or a microcapsule containing a synthetic resin and a color former, or a color developer that reacts with the color former precipitated from the microcapsule. The organic layer contains, for example, one or more selected from these.

[0044] As mentioned above, the term "organic matter" does not include cellulose, hemicellulose, and lignin.

[0045] This composite material containing paper and an organic layer other than paper may further contain one or more layers other than the paper and the organic layer.

[0046] Another example of waste paper is a mixture of the above composite material with waste paper that does not contain an organic layer, and consumers of paper products may not separate the waste paper that contains the organic layer from the waste paper that does not contain the organic layer when disposing of it.

[0047] The organic matter content of waste paper, which is a starting material for bioethanol, is, for example, in the range of 5.0 to 30.0 mass%, typically in the range of 6.0 to 25.0 mass%. Here, the organic matter content of waste paper is the proportion of organic matter in the solid content of the waste paper, and is a value obtained by excluding the proportions of cellulose, hemicellulose, and lignin in the solid content, and the proportions of ash.

[0048] According to one example, in waste paper as a starting material for bioethanol raw material, the proportions of each component in the solid content are within the following ranges: total of cellulose and hemicellulose: 50 to 94 mass %, lignin: 0.1 to 20.0 mass %, organic matter: 5.0 to 30.0 mass %, and ash: 0.9 to 15.0 mass %.

[0049] The amounts of "cellulose," "hemicellulose," and "lignin" are values ​​obtained by detergent analysis.

[0050] The amount of "ash" is a value obtained by the method specified in JIS P8251: 2003. The ash content is derived from inorganic substances contained in waste paper, such as silicon, phosphorus, iron, calcium, sodium, magnesium, and potassium, as well as compounds containing these substances, such as oxides, nitrides, and salts such as carbonates.

[0051] <2.2> Metal-Containing Waste Paper Yet another example of waste paper used as a starting material in the production of the bioethanol raw material described above is waste paper in the form of a composite material containing paper and a metal layer. The metal layer is, for example, a metal foil or a metal-deposited layer. The metal layer may also be a layer made of metal particles. The metal contained in the metal layer is, for example, an elemental metal or an alloy such as aluminum, gold, silver, or copper. The technology described herein is particularly useful when the composite material contains a metal foil or a layer made of metal particles as the metal layer.

[0052] The composite may further include one or more layers other than the paper and metal layers, for example, the composite may further include a printed layer.

[0053] Yet another example of recycled paper is a mixture of the composite material described above with recycled paper that does not contain a metal layer, and consumers of paper products may not distinguish the recycled paper that contains a metal layer from the recycled paper that does not contain a metal layer.

[0054] In one example, waste paper as a starting material for bioethanol has an ash content in the range of 1 to 30% by mass, and the proportion of the solid content remaining after removing cellulose, hemicellulose, lignin, and ash from the solid content (hereinafter sometimes abbreviated as "others") in the range of 5 to 30% by mass. In another example, waste paper as a starting material for bioethanol has a metal content in the ash in the range of 2 to 40% by mass.

[0055] More specifically, in waste paper used as a starting material for bioethanol raw material, the proportion of each component in the solid content is, for example, within the following ranges: total of cellulose and hemicellulose: 50 to 90 mass %, lignin: 0.5 to 15 mass %, ash: 1 to 30 mass %, others: 5 to 30 mass %.

[0056] The amounts of "cellulose," "hemicellulose," and "lignin," as well as the amount of "ash," are values ​​obtained by the methods described above.

[0057] The amount of "others" is calculated by subtracting the total amount of "cellulose," "hemicellulose," "lignin," and "ash" from the amount of solids in the waste paper. "Others" includes organic matter. Examples of organic matter included in "others" include one or more of the following: resins such as polyethylene, polyethylene terephthalate, and natural rubber; ink components such as pigments, resins, solvents, drying oils, acrylic acid oligomers, acrylic acid monomers, initiators, sensitizers, and adjuvants; additives such as sizing materials, fillers, paper strength agents, retention aids, dyes, pigments, and adhesives; microcapsules containing synthetic resins and color formers; and color developers that react with the color formers precipitated from the microcapsules.

[0058] <2.3> Waste paper containing organic layers other than paper and metals Yet another example of waste paper used as a starting material in the production of the bioethanol raw material described above is waste paper in the form of a composite material containing paper, an organic layer other than paper, and a metal layer. Yet another example of waste paper is a mixture of a composite material containing paper and an organic layer other than paper, and a composite material containing paper and a metal layer. Yet another example of waste paper is a mixture of one or more of the above composite materials with waste paper that contains neither an organic layer other than paper nor a metal layer.

[0059] <3> Manufacturing Method of Bioethanol Raw Material The manufacturing method of bioethanol raw material according to an embodiment of the present invention includes a pretreatment step and a subsequent purification step. The pretreatment step involves applying a shear force to waste paper or shredded waste paper containing paper, an organic layer other than paper, and / or metals in the presence of a predetermined amount of water. The purification step involves washing the fibers contained in the mixture produced by the pretreatment step with water.

[0060] <3.1> First Embodiment FIG. 2 is a flowchart showing a method for producing a bioethanol raw material according to a first embodiment of the present invention.

[0061] 2, the defibration step S11, dewatering step S12, kneading step S13, dilution step S14, filtration step S15, and washing and dewatering step S16 are carried out in this order. In this method, the pretreatment step consists of the defibration step S11, dewatering step S12, and kneading step S13. The refining step consists of the dilution step S14, filtration step S15, and washing and dewatering step S16. This method is particularly suitable when the starting material is waste paper that can be defibrated in water.

[0062] In the disintegration step S11, waste paper and water are put into a pulper and the mixture is agitated, thereby disintegrating the waste paper into fibers.

[0063] The amount of water is preferably in the range of 100 to 9900 parts by mass, and more preferably in the range of 150 to 2400 parts by mass, per 100 parts by mass of waste paper.

[0064] A defibration-promoting agent may be added to the mixture or to the water before mixing with the waste paper. The defibration-promoting agent promotes the defibration of the waste paper into fibers.

[0065] Examples of agents that can be used to promote disintegration include alkalis such as sodium hydroxide, sodium carbonate, and sodium silicate; oxidizing agents such as hypochlorite and hydrogen peroxide; acids such as sulfamic acid, hydrochloric acid, sulfuric acid, and phosphoric acid; and surfactants.

[0066] The agent for promoting disintegration is added to the mixture or to water before mixing with the waste paper, preferably to give an aqueous solution having a concentration in the range of 0.1 to 5% by weight, more preferably to give an aqueous solution having a concentration in the range of 0.2 to 3% by weight.

[0067] The waste paper, water, and disaggregation promoting agent may be mixed at any stage before the kneading step S13. For example, prior to putting the waste paper and water into the pulper, the waste paper, water, and disaggregation promoting agent may be put into a separate tank and stored for a certain period of time.

[0068] In the dehydration step S12, the mixture is dehydrated to increase its solid content. For example, a cylinder press is used for dehydration. This dehydration is preferably carried out so that the solid content of the dehydrated product is in the range of 20 to 40% by mass, more preferably in the range of 25 to 35% by mass.

[0069] In the kneading step S13, the dehydrated product is fed into a kneader and kneaded, thereby applying shear force to the solid content of the kneaded product, partially causing impurities such as ash to be detached from the fibers and migrate to water in this step, and facilitating the detachment of impurities from the fibers and migration to water in subsequent steps.

[0070] Shear force is applied to the solids contained in the kneaded material in the presence of water so that the solids concentration (sometimes referred to as solids content) is within the range of 10 to 40 mass%. This solids concentration is preferably within the range of 15 to 35 parts by mass. If the amount of water is too large, it becomes difficult to apply strong shear force to the solids, making it difficult to sufficiently separate impurities such as ash from the fibers in this process and subsequent processes. If the amount of water is too small, the fibers are difficult to disentangle, and impurities are unlikely to migrate into the water. Therefore, impurities are also unlikely to be detached from the fibers. Furthermore, the load on rotating bodies such as blades used in the kneading process becomes so large that they may become unable to rotate. For the purpose of adjusting the moisture content, water may be added to the dehydrated product before kneading, or to the kneaded material during kneading.

[0071] This kneading is preferably carried out while heating the kneaded material with steam or hot water, which further promotes separation of the fibers from impurities such as ash.

[0072] When steam heating is performed, the heating may be performed under atmospheric pressure or under pressurized conditions. When steam heating is performed, the pressure is preferably in the range of 0.1 to 0.6 MPa, more preferably in the range of 0.2 to 0.5 MPa.

[0073] When heating is carried out with steam or hot water, the kneaded material is preferably heated to a temperature in the range of 90 to 100°C, more preferably to a temperature in the range of 95 to 99°C.

[0074] The kneader used for kneading may be a continuous kneader or a batch kneader.

[0075] The kneader may include only one rotating body such as a blade and a screw, or may include multiple rotating bodies. When the kneader includes multiple blades, the blades may be arranged in a tangential or differential manner. When the kneader includes multiple screws, the screws may be arranged in an intermeshing or tangential manner. According to one example, an intermeshing twin-screw kneader is used.

[0076] The processing intensity in the kneader is preferably in the range of 80 to 300 kWh / pt, more preferably in the range of 100 to 200 kWh / pt, in terms of power source unit. The power source unit refers to the amount of power consumption required to process 1 ton of raw material.

[0077] The kneading in the kneader is preferably carried out for 1 to 10 minutes, more preferably for 3 to 5 minutes.

[0078] Here, a kneader is used to apply shear force to the solid content of the kneaded material. If a sufficient shear force can be applied to the solid content, instead of kneading with a kneader, for example, a stirrer may be used to perform stirring under conditions where the amount of water is small.

[0079] In the dilution step S14, the kneaded material and water are fed into a pulper and the mixture is stirred. This dilutes the mixture of solids and water. This operation produces an aqueous dispersion as a cellulose solution, and also transfers impurities adhering to the fibers into the water.

[0080] This dilution is preferably carried out so as to produce an aqueous dispersion having a solids concentration in the range of 0.1 to 5% by mass, more preferably so as to produce an aqueous dispersion having a solids concentration in the range of 0.2 to 2% by mass.

[0081] In the filtering step S15, a screen is used to remove relatively large impurities from the aqueous dispersion.

[0082] In the washing and dehydration step S16, the aqueous dispersion from which the relatively large impurities have been removed is centrifuged to remove at least a portion of the separated liquid containing the impurities from the fibers. Thereafter, if necessary, a cycle of adding water to the fibers and centrifuging them in this order is repeated one or more times.

[0083] The final dehydration removes the separated liquid so that the solids concentration is suitable for the saccharification step S2, for example. In one example, the final centrifugation removes the separated liquid so that the solids concentration is in the range of 1 to 10% by mass. In another example, the final centrifugation removes the separated liquid so that the solids concentration is in the range of 2 to 6% by mass.

[0084] In some cases, an additional dehydration treatment may be carried out. Examples of the additional dehydration method include a method using one or more of a cylinder press, a screw press, and a centrifugal dehydrator.

[0085] In this way, a bioethanol raw material containing fiber and water is obtained.

[0086] <3.2> Second embodiment FIG. 3 is a flowchart showing a method for producing a bioethanol raw material according to a second embodiment of the present invention.

[0087] 3, a crushing step S17, a kneading step S13, a dilution step S14, a filtration step S15, and a washing and dewatering step S16 are carried out in this order. In this method, the pretreatment step consists of the crushing step S17 and the kneading step S13. The refining step consists of the dilution step S14, a filtration step S15, and a washing and dewatering step S16. This method is particularly suitable when the starting material is or contains waste paper that is difficult to disintegrate in water.

[0088] The method illustrated in FIG. 3 is similar to the method described with reference to FIG. 2, except for the following points.

[0089] 3, a shredding step S17 is performed instead of the macerating step S11 and the dewatering step S12. In the shredding step S17, the waste paper is shredded into small pieces, for example, by a shredder.

[0090] The polymer layer is liquid-impermeable. If the recycled paper contains a liquid-impermeable layer, this layer inhibits defibration of the fibers.

[0091] In the method shown in Fig. 3, fibers are defibrated in the dilution step S14. When waste paper is shredded in the shredding step S17 and then the kneading step S13 is carried out, even if the waste paper contains a liquid-impermeable layer, the impediment to defibration and the like caused by this liquid-impermeable layer can be reduced.

[0092] When waste paper is shredded into thin lines or strips, the width is preferably 10 mm or less, more preferably 6 mm or less. There is no lower limit to this width, but it is, for example, 1 mm or more.

[0093] The kneading step S13 is the same as the kneading step S13 in the method of Fig. 2, except that instead of feeding the dehydrated product into the kneader, pulverized waste paper and water are fed into the kneader. Therefore, the kneading step S13 in the method of Fig. 3 can also employ the apparatus, procedures, conditions, etc. described with reference to Fig. 2. However, since the method of Fig. 3 feeds waste paper into the kneader without going through the defibration step S11, it is preferable to carry out the kneading step S13 while heating the kneaded material with steam.

[0094] The dilution step S14 is also similar to the dilution step S14 in the method of Fig. 2. Therefore, the dilution step S14 in the method of Fig. 3 can also employ the apparatus, procedures, conditions, etc. described with reference to Fig. 2.

[0095] It is preferable to perform the filtration step S15 without omitting it. Most of the impurities derived from the metal foil or polymer layer can be removed in the filtration step S15. The impurities derived from the metal foil or polymer layer may accumulate at the bottom of the tank in the saccharification step S2 or the fermentation step S3.

[0096] The washing and spin-drying step S16 is the same as the washing and spin-drying step S16 in the method of Fig. 2. Therefore, the method of Fig. 3 can also use the apparatus, procedures, conditions, etc. described with reference to Fig. 2 for the washing and spin-drying step S16.

[0097] <4> Bioethanol Raw Material The above method can produce a high-purity bioethanol raw material, i.e., a bioethanol raw material with a high total percentage of cellulose and hemicellulose in the solids, even if the starting waste paper contains a high percentage of prohibited substances or metals. In one example, the above method can produce a bioethanol raw material with a total percentage of cellulose and hemicellulose in the solids of 90.0% by mass or more. In another example, the above method can produce a bioethanol raw material with a total percentage of cellulose and hemicellulose in the solids of 95% by mass or more. In these bioethanol raw materials, the percentage of metals in the ash is, for example, in the range of 10 to 40% by mass.

[0098] According to the above method, when the total proportion of cellulose and hemicellulose in the solids of the waste paper starting material is high, it is possible to produce a bioethanol raw material in which the total proportion of cellulose and hemicellulose in the solids is nearly 100% by mass. However, when the waste paper starting material contains a high proportion of prohibited substances, metals, etc., the bioethanol raw material will contain a small amount of impurities. In this case, the total proportion of cellulose and hemicellulose in the solids of the bioethanol raw material obtained by the above method is 95% by mass or less in one example, and 99.5% by mass or less in another example.

[0099] When the proportion of prohibited substances in the waste paper used as the starting material is high, in one example, the proportion of each component in the solid content of the bioethanol raw material obtained by the above method falls within the following ranges: total of cellulose and hemicellulose: 90.0 to 99.5% by mass, lignin: 0 to 5.0% by mass, organic matter: 0.25 to 5.0% by mass, ash: 0.25 to 5.0% by mass.

[0100] When the starting waste paper contains a high proportion of metals, for example, the proportion of each component in the solid content of the bioethanol raw material obtained by the above method falls within the following ranges: total of cellulose and hemicellulose: 90 to 97% by mass, lignin: 0 to 5% by mass, ash: 0.1 to 6% by mass, others: remainder.

[0101] Thus, the bioethanol raw material obtained by the above method has a high ratio of the total of cellulose and hemicellulose to the solids. Furthermore, the bioethanol raw material obtained by the above method has a low ratio of organic matter or ash to the solids. These characteristics, which are not available with conventional methods as described below, are advantageous for producing bioethanol at a high yield.

[0102] As described above, calcium carbonate can be removed from biomass by blowing carbon dioxide into the aqueous slurry produced by pretreating waste paper to convert calcium carbonate into water-soluble calcium bicarbonate, followed by solid-liquid separation. However, this method can only remove calcium carbonate.

[0103] As mentioned above, the ash content of waste paper can be reduced by subjecting it to the same process used in deinking to produce recycled pulp from printed waste paper. However, deinking is not effective in reducing the organic matter contained in waste paper. Furthermore, if the waste paper used as the starting material contains a high proportion of metals, etc., general deinking cannot sufficiently remove the ash.

[0104] The organic matter contained in the bioethanol raw material increases the viscosity of the reaction liquid. Therefore, the organic matter contained in the bioethanol raw material inhibits the enzymatic saccharification reaction in the saccharification step S2 and the yeast fermentation reaction in the fermentation step S3. In addition, the ash contained in the bioethanol raw material also inhibits the enzymatic saccharification reaction in the saccharification step S2. Therefore, when using a bioethanol raw material obtained by blowing carbon dioxide into an aqueous slurry or by carrying out general deinking, it is not possible to produce bioethanol at a high yield.

[0105] In contrast, the bioethanol raw material obtained by the method described with reference to Figures 2 and 3 has a high proportion of cellulose and hemicellulose in the solids, and a low proportion of organic matter and ash in the solids. Therefore, when this bioethanol raw material is used, bioethanol can be produced at a high yield.

[0106] Furthermore, in the methods described with reference to Figures 2 and 3, preferably, only water is mixed with the waste paper. In this case, additives such as bases and deinking agents are not used, and therefore these substances do not adversely affect the enzymatic saccharification reaction in the saccharification step S2 or the fermentation in the fermentation step S3. Furthermore, even when only water is mixed with the waste paper in these methods, it is possible to produce a bioethanol raw material in which the total proportion of cellulose and hemicellulose in the solids is high and the proportion of organic matter and ash in the solids is low. Therefore, when bioethanol raw material is produced using these methods in which only water is mixed with the waste paper, bioethanol can be produced at a particularly high yield by using this bioethanol raw material.

[0107] If the starting waste paper contains a high proportion of prohibited substances, lignin may remain in the bioethanol raw material. Removing lignin before the saccharification step S2 requires harsh treatment conditions, such as high-temperature and high-pressure treatment or the addition of an acid or base. This results in a lower cellulose yield. Furthermore, the process conditions for removing lignin, as well as the chemical addition and associated washing, can increase the environmental impact.

[0108] Tests carried out in relation to the present invention are described below. <Test 1> (Example 1) A bioethanol raw material was produced by the method described with reference to FIG.

[0109] Here, we used a piece of recycled paper called "wamp." The wamp used here has a multi-layer structure consisting of paper and a polyethylene layer on top of it. Table 1 below shows the content of the components contained in this wamp.

[0110] In the shredding step S17, 5 kg of waste paper was fed into a shredder and shredded into strips with a width of 5.8 mm.

[0111] In the kneading step S13, the entire amount of shredded waste paper and water were fed into a kneader and kneaded. A New Taizen D15 model manufactured by Daizen Co., Ltd. was used as the kneader. The shredded waste paper was fed into the kneader in 10 separate batches. The amount of water was 10 L per 5 kg of waste paper. Kneading in the kneader was carried out under atmospheric pressure by heating the kneaded material to 98°C with steam and adding water as a liquid to the kneaded material as needed to maintain a constant moisture content. Kneading in the kneader was also carried out at a processing intensity of 100 kWh / pt.

[0112] In the dilution step S14, the entire amount of the kneaded material and 200 L of water were charged into a pulper, and the mixture was stirred. The pulper used was a Kyowa Iron Works 800-type slush pulper. The liquid temperature was 25°C. The rotation speed of the stirring blades was 700 rpm. Stirring was carried out for 10 minutes. As a result, an aqueous dispersion with a solid content of 1% by mass was obtained as a cellulose solution.

[0113] In the filtration step S15, a 6-cut (0.15 mm) slit screen was used to remove relatively large impurities from the aqueous dispersion.

[0114] In the washing and dehydration step S16, the entire amount of the aqueous dispersion was first subjected to centrifugation using a centrifuge / extractor. A Vertical Z centrifugal separator manufactured by Daizen Co., Ltd. was used as the centrifuge / extractor. In this manner, dehydration by centrifugal force, rubbing washing with stirring blades, and displacement washing with injected water were performed consecutively. This resulted in 40 kg of aqueous dispersion with a solids content of 5%. The entire amount of this aqueous dispersion was then subjected to dehydration using a dehydrator. In this manner, 6.7 kg of bioethanol raw material with a solids content of 30% by mass was obtained.

[0115] The composition of the bioethanol feedstock thus obtained was then analyzed, and the results are shown in Table 1 below.

[0116] (Example 2) Bioethanol raw material was produced in the same manner as in Example 1, except for the following points. That is, instead of using wrap as waste paper, a paper can-type container (cartocan) was used. The paper can-type container used here was made of a packaging material in which a resin layer was provided on both sides of the paper. The content of the components contained in this paper can-type container is shown in Table 1 below.

[0117] In this way, 10 kg of bioethanol feedstock with a solid content of 30% by mass was obtained. The composition of the bioethanol feedstock thus obtained was then analyzed. The results are shown in Table 1 below.

[0118] (Example 3) Bioethanol raw material was produced in the same manner as in Example 1, except for the following points. That is, instead of using wrap as recycled paper, paper cups were used. The paper cups used here were made of a packaging material with multiple resin layers on both sides of the paper. The contents of the components contained in this paper cup are listed in Table 1 below.

[0119] In this way, 7.5 kg of bioethanol feedstock with a solid content of 30% by mass was obtained. The composition of the bioethanol feedstock thus obtained was then analyzed. The results are shown in Table 1 below.

[0120] (Example 4) Bioethanol raw material was produced in the same manner as in Example 1, except for the following points. That is, instead of using wrap, bonded postcards were used as recycled paper. The bonded postcards used here have a multilayer structure with rubber layers on both sides of the paper. The content of the components contained in these bonded postcards is shown in Table 1 below.

[0121] In this way, 12.5 kg of bioethanol feedstock with a solid content of 30% by mass was obtained. The composition of the bioethanol feedstock thus obtained was then analyzed. The results are shown in Table 1 below.

[0122] Example 5 A bioethanol raw material was produced by the method described with reference to FIG.

[0123] Here, carbonless paper was used as the recycled paper. The carbonless paper used here has a structure in which a paper sheet with a layer of microcapsules containing a color former on one side and a paper sheet with a color developer are laminated together so that the microcapsule layer and the color developer layer are interposed between the two sheets. The content of the components contained in this carbonless paper is shown in Table 1 below.

[0124] In the defibration step S11, first, 5 kg of waste paper was put into a pulper, then 125 L of water was put into the pulper, and then these were stirred. As the pulper, an 800-type slush pulper manufactured by Kyowa Iron Works Co., Ltd. was used. The liquid temperature was 25°C. The rotation speed of the stirring blade was 700 rpm. The stirring was carried out for 10 minutes.

[0125] In the dehydration step S12, the entire mixture obtained in the maceration step S11 was dehydrated using a cylinder press. A double-cylinder cylinder press was used. This dehydration yielded 16.7 kg of a dehydrated product with a solid content of 30% by mass.

[0126] In the kneading step S13, the entire amount of the dehydrated product obtained in the dehydration step S12 was kneaded using a kneader. A New Taizen D15 model kneader manufactured by Daizen Co., Ltd. was used. The dehydrated product was sequentially charged into the kneader in 10 batches. Kneading using the kneader was carried out under atmospheric pressure by heating the kneaded product to 98°C with steam. Liquid water was added to the kneaded product as needed to maintain a constant moisture content. The kneading using the kneader was carried out at a processing intensity of 100 kWh / pt.

[0127] The dilution step S14 was carried out in the same manner as in Example 1. The filtration step S15 was also carried out in the same manner as in Example 1. The washing and dehydration step S16 was also carried out in the same manner as in Example 1.

[0128] In this way, 14.2 kg of bioethanol feedstock with a solid content of 30% by mass was obtained. The composition of the bioethanol feedstock thus obtained was then analyzed. The results are shown in Table 1 below.

[0129] Example 6 A bioethanol raw material was produced by the method described with reference to FIG.

[0130] Here, foil-stamped paper containers were used as recycled paper. The foil-stamped paper containers used here were made of packaging material with a structure in which paper and aluminum foil were bonded together. The content of the components contained in these foil-stamped paper containers is shown in Table 1 below. In addition, the proportion of metals in the ash content of these foil-stamped paper containers was 21% by mass.

[0131] In the shredding step S17, 5 kg of waste paper was fed into a shredder and shredded into strips with a width of 5.8 mm.

[0132] In the kneading step S13, the entire amount of shredded waste paper and water were fed into a kneader and kneaded. A New Taizen D15 model manufactured by Daizen Co., Ltd. was used as the kneader. The shredded waste paper was fed into the kneader in 10 separate batches. The amount of water was 10 L per 5 kg of waste paper. Kneading in the kneader was carried out under atmospheric pressure by heating the kneaded material to 98°C with steam and adding water as a liquid to the kneaded material as needed to maintain a constant moisture content. Kneading in the kneader was also carried out at a processing intensity of 100 kWh / pt.

[0133] In the dilution step S14, the entire amount of the kneaded material and 200 L of water were charged into a pulper, and the mixture was stirred. The mass of the material before dilution was 7.5 kg, and the solid content was 30% by mass. The pulper used was a Kyowa Iron Works 800-type slush pulper. The liquid temperature was 25°C. The rotation speed of the stirring blades was 700 rpm. Stirring was carried out for 10 minutes. As a result, an aqueous dispersion with a solid content of 1% by mass was obtained as a cellulose solution.

[0134] In the filtration step S15, a 6-cut (0.15 mm) slit screen was used to remove relatively large impurities from the aqueous dispersion. In the washing and dehydration step S16, the entire aqueous dispersion was first centrifuged using a centrifuge / extractor. A Daizen Vertical Z centrifuge / extractor was used. In this way, dehydration by centrifugal force, rubbing washing with stirring blades, and replacement washing with injected water were performed continuously. This resulted in 70 kg of aqueous dispersion with a solids content of 5%. The entire aqueous dispersion was then dehydrated using a dehydrator. In this way, 11.7 kg of bioethanol raw material with a solids content of 30% by mass was obtained.

[0135] The composition of the bioethanol feedstock thus obtained was then analyzed, and the results are shown in Table 1 below.

[0136] Comparative Example 1 A bioethanol raw material was produced in the same manner as in Example 1, except that a defibration step was carried out instead of the kneading step S13. In the defibration step, 5 kg of waste paper was put into a pulper, followed by 100 L of water, and then these were stirred. The composition of the bioethanol raw material thus obtained was then analyzed. The results are shown in Table 2 below.

[0137] (Comparative Example 2) An attempt was made to produce a bioethanol raw material using the same method as in Example 1, except that in the kneading step S13, the amount of water was 2.5 L per 5 kg of waste paper. However, the load on the rotating blades in the kneader in the kneading step S13 became too large, and processing could not be carried out.

[0138] Comparative Example 3 A bioethanol raw material was produced in the same manner as in Example 1, except that the kneading step S13 was not performed. The composition of the bioethanol raw material thus obtained was then analyzed. The results are shown in Table 2 below.

[0139] Comparative Example 4 A bioethanol raw material was produced in the same manner as in Example 2, except that a defibration step was carried out instead of the kneading step S13. In the defibration step, 5 kg of waste paper was put into a pulper, followed by 100 L of water, and then these were stirred. The composition of the bioethanol raw material thus obtained was then analyzed. The results are shown in Table 2 below.

[0140] (Comparative Example 5) An attempt was made to produce bioethanol raw material using the same method as in Example 2, except that in the kneading step S13, the amount of water was 2.5 L per 5 kg of waste paper. However, the load on the rotating blades in the kneader in the kneading step S13 became too large, and processing could not be carried out.

[0141] Comparative Example 6 A bioethanol raw material was produced in the same manner as in Example 2, except that the kneading step S13 was not performed. The composition of the bioethanol raw material thus obtained was then analyzed. The results are shown in Table 2 below.

[0142] Comparative Example 7 A bioethanol raw material was produced in the same manner as in Example 3, except that a defibration step was carried out instead of the kneading step S13. In the defibration step, 5 kg of waste paper was put into a pulper, followed by 100 L of water, and then these were stirred. The composition of the bioethanol raw material thus obtained was then analyzed. The results are shown in Table 3 below.

[0143] (Comparative Example 8) An attempt was made to produce bioethanol raw material using the same method as in Example 3, except that in the kneading step S13, the amount of water was 2.5 L per 5 kg of waste paper. However, the load on the rotating blades in the kneader in the kneading step S13 became too large, and processing could not be carried out.

[0144] Comparative Example 9 A bioethanol raw material was produced in the same manner as in Example 3, except that the kneading step S13 was not performed. The composition of the bioethanol raw material thus obtained was then analyzed. The results are shown in Table 3 below.

[0145] Comparative Example 10 A bioethanol raw material was produced in the same manner as in Example 4, except that a defibration step was carried out instead of the kneading step S13. In the defibration step, 5 kg of waste paper was put into a pulper, followed by 100 L of water, and then these were stirred. The composition of the bioethanol raw material thus obtained was then analyzed. The results are shown in Table 3 below.

[0146] (Comparative Example 11) An attempt was made to produce bioethanol raw material using the same method as in Example 4, except that in the kneading step S13, the amount of water was 2.5 L per 5 kg of waste paper. However, the load on the rotating blades in the kneader in the kneading step S13 became too large, and processing could not be carried out.

[0147] Comparative Example 12 A bioethanol raw material was produced in the same manner as in Example 3, except that the kneading step S13 was not performed. The composition of the bioethanol raw material thus obtained was then analyzed. The results are shown in Table 3 below.

[0148] Comparative Example 13 A bioethanol raw material was produced in the same manner as in Example 5, except that in the dehydration step S12, dehydration was carried out so that the solids content of the dehydrated product was 5% by mass, and this dehydrated product was subjected to the above-mentioned maceration step using a pulper instead of being subjected to the kneading step S13. The composition of the bioethanol raw material thus obtained was then analyzed. The results are shown in Table 4 below.

[0149] (Comparative Example 14) An attempt was made to produce a bioethanol raw material by the same method as in Example 5, except that in the dehydration step S12, dehydration and drying were performed so that the solid content of the dehydrated product would be 70% by mass, and this dehydrated product was fed into a kneader in the kneading step S13. However, the load on the rotating blades of the kneader in the kneading step S13 became too large, and processing could not be carried out.

[0150] Comparative Example 15 A bioethanol raw material was produced in the same manner as in Example 5, except that the kneading step S13 was not performed. The composition of the bioethanol raw material thus obtained was then analyzed. The results are shown in Table 4 below.

[0151] Comparative Example 16 A bioethanol raw material was produced in the same manner as in Example 6, except that in the kneading step S13, the amount of water was 100 L per 5 kg of waste paper. The composition of the bioethanol raw material thus obtained was then analyzed. The results are shown in Table 4 below.

[0152] (Comparative Example 17) An attempt was made to produce a bioethanol raw material using the same method as in Example 6, except that in the kneading step S13, the amount of water was 2.5 L per 5 kg of waste paper. However, the load on the rotating blades in the kneader in the kneading step S13 became too great and processing could not be carried out.

[0153] Comparative Example 18 A bioethanol raw material was produced in the same manner as in Example 6, except that the kneading step S13 was not performed. The composition of the bioethanol raw material thus obtained was then analyzed. The results are shown in Table 4 below.

[0154]

[0155]

[0156]

[0157]

[0158] In Tables 1 to 4, "2_Mixing" and "3_Mixing" in the "Process" column indicate that a bioethanol feedstock was produced by the method shown in Figure 2 and that a bioethanol feedstock was produced by the method shown in Figure 3, respectively. In Tables 2 to 4, "2_None" and "3_None" in the "Process" column indicate that a bioethanol feedstock was produced by the same method as shown in Figure 2 except that kneading was omitted, and that a bioethanol feedstock was produced by the same method as shown in Figure 3 except that kneading was omitted, respectively. In addition, in Tables 2 to 4, "2_Decomposition" and "3_Decomposition" in the "Process" column indicate that a bioethanol feedstock was produced by the same method as shown in Figure 2 except that maceration was performed instead of kneading, and that a bioethanol feedstock was produced by the same method as shown in Figure 3 except that maceration was performed instead of kneading, respectively. In addition, "Solid content concentration" in Tables 1 to 4 is the solid content (derived from waste paper or its shreds) of the treated product during kneading or treatment performed instead of kneading.

[0159] As shown in Table 1, in Examples 1 to 6, high-purity bioethanol raw materials were produced, specifically bioethanol raw materials with low proportions of organic matter and ash in the solids and high proportions of the total of cellulose and hemicellulose in the solids. Note that in the bioethanol raw material obtained in Example 6, the proportion of metals in the ash was 17 mass%.

[0160] In contrast, as shown in Tables 2 to 4, the amount of water used during kneading was either too small or too large, and a high-purity bioethanol raw material could not be produced in Comparative Examples 2, 5, 8, 11, 14, and 17. Furthermore, other Comparative Examples that employed methods other than kneading also failed to produce a high-purity bioethanol raw material.

[0161] <Test 2> Bioethanol was produced from the bioethanol raw materials produced in Examples 1 to 6 by sequentially performing the saccharification step S2, fermentation step S3, and distillation step S4 described with reference to FIG. 1 . Bioethanol was also produced from the waste paper used in the production of the bioethanol raw materials in Examples 1 to 6 by the same method as above, except that the pretreatment step S1 was omitted. The ethanol yield was calculated as the ratio of the ethanol yield based on the raw material input to the saccharification step S2 when the pretreatment step S1 was performed to the ethanol yield based on the raw material input to the saccharification step S2 when the pretreatment step S1 was omitted. The results are shown in Table 5 below.

[0162] The ease of disintegration of waste paper is also shown in Table 5. The ease of disintegration was confirmed by the following method.

[0163] [Method for confirming ease of disintegration] (1) Waste paper was cut into small pieces with scissors, and 100 g of the small pieces (solid content) was mixed with water so that the solid content concentration was 5% by mass. This mixture was stirred for approximately 15 minutes in a standard disintegrator specified in JIS P8220-1.2:2012. (2) A portion of the mixed solution after stirring (60 g solid content) was extracted and placed in a flat screen screen box, and water was poured into the screen box for 15 minutes. Here, a slit screen plate with a 6-cut (0.15 mm) screen plate slit was used. (3) Thereafter, visual observation was performed. If almost no residue was generated on the slit screen plate, it was evaluated as "disintegrable," and if residue was generated on the slit screen plate, it was evaluated as "difficult to disintegrate."

[0164]

[0165] As shown in Table 5, regardless of the type of waste paper, the ethanol yield could be significantly increased by performing the pretreatment step S1.

[0166] S1...pretreatment step, S2...saccharification step, S3...fermentation step, S4...distillation step, S11...macerating step, S12...dehydration step, S13...kneading step, S14...dilution step, S15...filtration step, S16...washing and dehydration step, S17...crushing step.

Claims

1. A bioethanol raw material derived from waste paper containing at least one of an organic layer other than paper and metal, wherein the total proportion of cellulose and hemicellulose in the solids is within the range of 90.0 to 99.5 mass%, the proportion of organic matter excluding cellulose, hemicellulose, and lignin in the solids is within the range of 0.25 to 5.0 mass%, and the proportion of ash in the solids is within the range of 0.25 to 5.0 mass%.

2. The bioethanol raw material according to claim 1, wherein the proportion of metals in the ash is in the range of 10 to 40 mass%.

3. A method for producing bioethanol, comprising producing bioethanol from the bioethanol raw material according to claim 1 or 2.

4. A method for producing a bioethanol raw material, comprising: carrying out a pretreatment process involving applying shear force to waste paper or shredded waste paper containing paper, an organic layer other than paper, and / or metals in the presence of water so that the solids concentration is within the range of 10 to 40% by mass; and carrying out a purification process involving washing with water the fibers contained in the mixture produced by the pretreatment process.

5. The manufacturing method described in claim 4, wherein the waste paper has a total cellulose and hemicellulose content in the range of 50 to 94 mass%, an organic matter content excluding cellulose, hemicellulose, and lignin in the range of 5.0 to 30.0 mass%, and an ash content in the range of 1.0 to 15.0 mass%.

6. A manufacturing method as described in claim 4, wherein the waste paper has an ash content in the range of 1 to 30% by mass, and the proportion of the solid content remaining after removing cellulose, hemicellulose, lignin, and ash from the solid content is in the range of 5 to 30% by mass.

7. The manufacturing method according to claim 6, wherein the proportion of metals in the ash of the waste paper is in the range of 2 to 40 mass %.

8. A manufacturing method according to any one of claims 4 to 7, wherein the shear force is applied to the waste paper or the shredded material by kneading.

9. The manufacturing method according to claim 8, wherein the kneading is carried out while the waste paper or the shredded material is heated with steam or hot water.

10. A manufacturing method described in any one of claims 4 to 9, wherein the pretreatment step further includes sequentially subjecting the waste paper or the shredded material to a maceration treatment and a dehydration treatment prior to applying the shear force to the waste paper or the shredded material.

11. A manufacturing method described in any one of claims 4 to 10, wherein the pretreatment step further includes crushing the waste paper to produce the shredded material prior to applying the shear force to the waste paper or the shredded material, and the shear force is applied to the shredded material.

12. A manufacturing method described in any one of claims 4 to 11, wherein the pretreatment step further comprises supplying a chemical agent to the waste paper or the shredded material to promote disintegration prior to applying the shear force to the waste paper or the shredded material.

13. The method of any one of claims 4 to 12, wherein washing the fibers with water includes diluting the mixture with water to obtain a cellulose solution, and centrifuging the cellulose solution to remove at least a portion of the impurities from the cellulose solution.

14. The method of any one of claims 4 to 12, wherein the purification step further comprises, prior to washing the fibers with water, diluting the mixture with water to obtain a diluted solution, and filtering the diluted solution to obtain a cellulose solution, and the washing of the fibers with water includes centrifuging the cellulose solution to remove at least a portion of impurities from the cellulose solution.

15. The method of claim 13 or 14, further comprising subjecting the cellulose solution from which at least a portion of the impurities have been removed to dehydration.

16. A manufacturing method described in any one of claims 4 to 15, which obtains a bioethanol raw material in which the total proportion of cellulose and hemicellulose in the solid content is in the range of 90.0 to 99.5 mass%, the proportion of organic matter excluding cellulose, hemicellulose, and lignin in the solid content is in the range of 0.25 to 5.0 mass%, and the proportion of ash in the solid content is in the range of 0.25 to 5.0 mass%.

17. The method for producing bioethanol raw material according to claim 16, wherein the proportion of metals in the ash is in the range of 10 to 40 mass %.

18. A method for producing bioethanol, comprising: producing a bioethanol raw material by the production method according to any one of claims 4 to 17; and producing bioethanol from the bioethanol raw material.

Images