Circulation grinding processing device, circulation grinding processing method, alcohol production method, and method for producing cellulose-containing composition

Abstract

To provide a circulation grinding device that can stably perform the process of circulation grinding including a circulation path for a long time from the beginning.SOLUTION: A circulation grinding device 1 includes: a grinder 100 in which the bottom of a container 101 is provided with an inlet 103 for the treated slurry, the inside of the container 101 is provided with a rotation mechanism 102 for grinding the treated slurry, and the top of the container 101 is provided with an outlet 104 for the treated slurry; an outer circulation path 200 for the treated slurry that is linked to the outlet of the grinder; and a screw feeder 300 that feeds the treated slurry discharged from the outlet of the outer circulation path to the inlet of the grinder. The treated slurry is circulated in the order of the grinder, the outer circulation path, and the screw feeder and subjected to the grinding process.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a circulating grinding apparatus, and particularly to a circulating grinding apparatus suitable for grinding a high-concentration slurry-like processed material, a circulating grinding method using the circulating grinding apparatus, a method for producing alcohol, and a method for producing a composition containing cellulose.

Background Art

[0002] Lignocellulosic biomass is composed of polysaccharides in which a large number of sugars such as cellulose and hemicellulose are bonded, and lignin having a large number of benzene rings. A highly structured and hardly soluble polymer composition formed by cellulose, hemicellulose, and lignin is also called lignocellulose. Cellulose exhibits crystallinity, and fibers formed by its aggregation or aggregates thereof are very strong. Furthermore, since lignin strongly adheres to and covers these strong fibers, a very strong laminated structure is formed. The reason why wood materials are used as structural materials is because of their strong and durable structure. This strong and durable structure becomes an obstacle when isolating cellulose from lignocellulosic biomass or when decomposing cellulose into monosaccharides. Starch, which is the same polysaccharide, does not have such a strong structure, so it can be easily decomposed into monosaccharides and converted into ethanol.

[0003] As saccharification methods for the ethanol production process from cellulose, various methods have been proposed so far, but they can be mainly classified into an acid saccharification method and an enzymatic saccharification method. The acid saccharification method is a method of directly decomposing cellulose into monosaccharides with a strong acid such as sulfuric acid, and has the merit that the reaction proceeds in a short time. However, there are problems such as the generation of fermentation inhibitors due to over-decomposition, and the need for acid-resistant equipment, recovery, and treatment of sulfuric acid from the saccharified solution and waste liquid, resulting in a high environmental load. On the one hand, in the enzymatic saccharification method, the enzymatic reaction proceeds at a relatively low temperature of about 50°C and does not require a large amount of strong acid or strong alkali chemicals, etc., so there is an advantage of low environmental impact. However, it has the disadvantage of requiring a longer reaction time compared to the acid saccharification method described above. In addition, there are extremely many enzymes collectively called cellulase, and it is necessary to select and formulate appropriate enzymes for the target cellulose and hemicellulose. Currently, there is also a problem of high cost. Furthermore, the biggest problem with the enzymatic saccharification method is that the strong lignin structure becomes an obstacle and the enzymatic reaction does not proceed as it is. That is, there is a problem that lignin covers cellulose and hemicellulose, making it difficult for enzymes to physically reach cellulose and hemicellulose.

[0004] In recent years, cellulose fibers have attracted attention as materials with a small environmental impact regarding production and disposal because they are derived from plants. Despite being lightweight, cellulose fibers have excellent properties such as a modulus of elasticity as high as that of aramid fibers known for high-strength fibers, and as little expansion and contraction with temperature changes as glass fibers. Examples of the uses of cellulose fibers include using the fibers as a heat insulating material and using them as a filler dispersed in a resin. In particular, a composite material in which cellulose fibers are dispersed in a biodegradable resin may expand the uses of the biodegradable resin by achieving both biodegradability and strength, and is expected to contribute to solving the marine plastic problem. In addition, cellulose nanofibers prepared on the nano order are expected to be utilized in various fields such as filter members, high gas barrier packaging members, electronic devices, food, medicine, cosmetics, and healthcare. Cellulose fibers can be obtained by defibrating plant-derived fibers such as pulp. Defibration is carried out in the presence of enzymes, etc. as necessary. Cellulose fibers may contain components other than cellulose depending on their use. In this case, by pulverizing plant biomass containing cellulose, the cellulose is separated, and by further proceeding with the pulverization process, the cellulose is defibrated, and a composition containing cellulose fibers can be obtained.

[0005] Here, wet pulverization is an operation of pulverizing the pulverization raw material in a state of being dispersed in a liquid, that is, in a slurry state. Since the particles are dispersed in water or the like, it is easy to finely pulverize them, and the achieved particle size is finer than that of dry pulverization. Therefore, it is used in the production of bioethanol and the production of cellulose fibers described above. For example, Patent Document 1 discloses a method of obtaining cellulose fibers on the order of micrometers by finely pulverizing plant fibers by wet pulverization using a bead mill. However, in a bead mill, it is difficult to pulverize a slurry-like processed material with high viscosity, and the solid content concentration of the raw material cannot be increased. The slurry-like processed material prepared in this way contains a large amount of water, so there is a problem of consuming a huge amount of energy to remove a large amount of moisture in the subsequent process.

[0006] In addition, wet pulverization is classified into a batch type and a continuous type. In the batch type, there is a lot of adhesion of the processed material to the container and members of the pulverization device for a single input amount, and since these cannot be recovered, the yield deteriorates. Generally, about 20% to 30% of the input solid content is discarded. In addition, since the batch type has a small processing amount per time, a large number of processes are required for large-scale processing. The large number of processes means that the number of batch switches also increases, and it is inevitable to clean during switching, resulting in an even larger amount of waste. On the one hand, a continuous process usually means a one-pass process in which the material to be processed passes through once, and sufficient grinding cannot be achieved. Therefore, a circulation process in which the material discharged from the grinding section is circulated and ground again is being considered. The advantages of the circulation process include not only the ability to perform fine grinding, but also the ability to perform a large amount of grinding at once by providing a tank or the like to expand the circulation path. Even if the processing capacity of the grinding means is the same, by providing an external circulation path, a large amount of ground product can be obtained only by the operator setting the material to be processed, starting the operation, and waiting for the processing, so a significant improvement in work efficiency can be expected.

[0007] In the bead mill described above, for the purpose of efficiently processing a large amount, as shown in FIG. 8, a circulating grinding process having a circulation path equipped with a tank is being carried out. However, in a bead mill, as described above, when the viscosity of the slurry is high, the grinding efficiency by the beads decreases. Also, a bead mill requires a mechanism (such as a screen) for separating the beads. When processing a high-viscosity slurry or when the flow rate of the slurry is high, the beads become biased, and this is also a factor contributing to the decrease in grinding efficiency. Therefore, in the circulating grinding process of a bead mill, it is necessary to further lower the solid content concentration (for example, about 1% by mass). Since the slurry-like material to be processed prepared in this way contains a larger amount of water, there is a problem of consuming an even larger amount of energy to remove the moisture in the subsequent process.

[0008] As a wet grinding device that does not use beads, Patent Document 2 discloses a grinding device in which a main shaft that rotates at the center of a container is erected, a plurality of sub-shafts are peripherally supported on the main shaft at intervals, a plurality of ring-shaped members are fitted to the sub-shafts with a sufficient gap between the sub-shafts, and the ring-shaped members are brought into contact with the inner wall of the container. It is described in this Patent Document 2 that the grinding device disclosed therein can perform not only a batch process but also a continuous process (one-pass process).

[0009] According to Patent Document 3, the same pulverizing device as that disclosed in Patent Document 2 is described as being capable of mixing and pulverizing a slurry of calcium phosphate with a solid content concentration of 40% by weight. Since the pulverizing device disclosed in Patent Document 2 can pulverize a highly viscous slurry-like processed material with a high solid content concentration in this way, if a circulation pulverization process is performed using this pulverizing device, it is expected that a large amount of processed material can be wet-pulverized without dilution to lower the solid content concentration. In particular, by applying it to the wet pulverization of woody materials or plant-derived fibers, it is expected that the production of bioethanol and the production of cellulose fibers described above can be carried out in a larger amount and more efficiently than before. According to the study by the present inventors, it has been found that the pulverizing device of Patent Document 2 can pulverize a slurry-like processed material with a high solid content concentration up to 15% by mass when used for the wet pulverization of woody materials or plant-derived fibers.

[0010] However, even in the case of the pulverizing device described in Patent Document 2 above, when a circulation pulverization process having an external circulation path as shown in FIG. 8 is performed, it has been found that there are the following problems. When an external tank or the like is provided to greatly expand the circulation path, as a whole system, a larger amount of processed material will circulate in the circulation path compared to the conventional batch type. For example, depending on the capacity of the external tank, the amount of processed material circulating will exceed ten times that of the batch type. In such a case, it has been found that the material that is easy to flow will preferentially circulate throughout the circulation path, and even when the pulverizing device described in Patent Document 2 is used, the pulverization process of the solid content (processed material) will not proceed as expected. In particular, this tendency has been found to be significant in the pulverization process of plant-based biomass materials that are easy to separate from water, such as woody materials, and the defibration process of pulp. In the pulverizer of Patent Document 2, a slurry-like processed material is supplied from the bottom surface of the device, and inside the pulverizer, the slurry-like processed material has a structure in which it is transferred upward against gravity. This has the advantage that the pulverization process proceeds reliably even when starting from a state with a high solid content. On the other hand, when performing a circulating pulverization process having a circulation path equipped with an external tank, a difference occurs in the circulation speed of water and solids at various locations in the circulation path, particularly immediately before the supply port of the pulverizer. It was speculated that the input of the difficult-to-flow solids (processed material) into the pulverizer was delayed, hindering the progress of the pulverization process of the solids (processed material). Also, in the circulating pulverization process of plant-based biomass, the slurry-like processed material is initially a mixture of water and solids, but the viscosity increases as the pulverization process progresses. Particularly when the solid content concentration is high, such changes in properties and viscosity are significant. If a conveying means that can relatively cope with the initial circulation process of the mixture of water and solids is selected, there is a problem that the viscosity increases over time and the conveyance of the slurry-like processed material becomes impossible, making it difficult to construct a simple system that can cope from the initial stage to over time for large-scale processing.

Prior Art Documents

Patent Documents

[0011]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0012] The present invention has been made in view of the problems of the above-described background art, and an object thereof is to provide a circulating pulverization processing apparatus capable of stably performing a circulating pulverization process having a circulation path from the initial stage to over time. In particular, it is an object to provide a circulating pulverization processing apparatus capable of performing a large amount of circulating pulverization processing on plant-based biomass materials, particularly wood materials and plant-derived fibers, in the state of a slurry-like processed product having a high solid content concentration.

Means for Solving the Problems

[0013] To achieve the above object, the present invention provides a circulating pulverization processing apparatus, a circulating pulverization processing method, a method for producing alcohol, and a method for producing a composition containing cellulose as described in the following [1] to [9]. 〔1〕A pulverization device provided with a supply port for a slurry-like processed product at the lower part of a container, having a rotating main shaft erected inside the container, a plurality of sub-shafts peripherally supported at intervals on the main shaft, a plurality of ring-shaped members fitted to the sub-shafts with a gap therebetween, the ring-shaped members being arranged to contact the inner wall of the container, and having a discharge port for a slurry-like processed product provided at the upper part of the container, An external circulation path section for a slurry-like processed product connected to the discharge port of the pulverization device, A screw feeder for conveying the slurry-like processed product discharged from the discharge port of the external circulation path section to the supply port of the pulverization device, The screw feeder is arranged from the discharge port of the external circulation path section to the supply port of the pulverization device, Characterized in that the slurry-like processed product is circulated in the order of the pulverization device, the external circulation path section, and the screw feeder to perform a pulverization process. Circulating pulverization processing apparatus. 〔2〕The circulating pulverization processing apparatus according to [1] above, characterized in that the external circulation path section includes an external tank. 〔3〕The screw feeder has a tip end that extends further downstream than directly below the supply port of the pulverizing device. The screw blades of the screw feeder are formed in the feeding direction up to immediately before the supply port of the pulverizing device, are not formed directly below the supply port, and are formed in the return direction on the downstream side of the supply port. The circulating pulverization processing apparatus according to the above 〔1〕 or 〔2〕. 〔4〕The screw feeder is formed as a twin-screw. The circulating pulverization processing apparatus according to any one of the above 〔1〕 to 〔3〕. 〔5〕A circulating pulverization processing method, characterized by using the circulating pulverization processing apparatus according to any one of the above 〔1〕 to 〔4〕 to perform a circulating pulverization process on a slurry-like processed material of plant biomass. 〔6〕The slurry-like processed material is a slurry of plant biomass with a solid content concentration of 3 to 15% by mass. The circulating pulverization processing method according to the above 〔5〕. 〔7〕The plant biomass is any one of woody, herbaceous, and cellulose-based biomass. The circulating pulverization processing method according to the above 〔5〕 or 〔6〕. 〔8〕A method for producing alcohol, characterized by using the circulating pulverization processing apparatus according to any one of the above 〔1〕 to 〔4〕 to perform a circulating pulverization process on a slurry-like processed material of plant biomass, and subjecting the obtained pulverized processed material to saccharification and fermentation processing. 〔9〕A method for producing a composition containing cellulose fibers, characterized by using the circulating pulverization processing apparatus according to any one of the above 〔1〕 to 〔4〕 to perform a circulating pulverization process on a slurry-like processed material of plant biomass.

Advantages of the Invention

[0014] According to the circulating pulverization processing apparatus according to the present invention described above, a circulating pulverization process having a circulation path can be stably performed from the initial stage to over time. In particular, plant biomass, especially woody materials and plant-derived fibers, can be circulated and pulverized in large quantities in the state of a slurry-like processed material with a high solid content concentration.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0016] Hereinafter, an embodiment of the circulating grinding apparatus according to the present invention will be described in detail with reference to the drawings.

[0017] As shown in FIGS. 1 to 3, the circulating grinding apparatus 1 according to the present invention includes a grinding apparatus 100, an external circulation path section 200, and a screw feeder 300.

[0018] As shown in detail in FIGS. 4 and 5, the grinding apparatus 100 includes a cylindrical container 101, a rotation mechanism 102 provided in the container 101, a supply port 103 for a slurry-like processed material formed at the lower part of the container, and a discharge port 104 for the slurry-like processed material formed at the upper part of the container.

[0019] The above-described container 101 has an inner peripheral surface 105 having a central axis in the vertical direction, and the above-described rotating mechanism 102 is installed in the container 101 that serves as a processing chamber. This rotating mechanism 102 includes a main shaft 106 that has the same central axis as the container 101, a pair of upper and lower pressing plates 107 and 108 that are fixed at regular intervals in the longitudinal direction of the main shaft 106, and a sub-shaft 109 that is fixed between the pressing plates 107 and 108 so as to be parallel to and equidistant from the main shaft 106.

[0020] The above-described pressing plates 107 and 108 are shaped such that they radially project the same number of arms as the number of sub-shafts 109. By making the shape of these pressing plates 107 and 108 not a simple disk shape but a shape having gaps between the arms, the degree of convection (mixing) of the slurry-like processed material introduced into the container 101 is improved, and it is possible to minimize the amount of processed material that accumulates as dead stock on the upper pressing plate 107.

[0021] The above-described sub-shaft 109 is a long bolt-shaped member, and each end is inserted into through holes provided at the tips of the arm-shaped portions of both pressing plates 107 and 108 and is fastened and fixed by nuts 110. Also, the upper end portion of the main shaft 106 is configured to be directly connected to a drive source such as a motor (not shown), or to have a pulley attached and transmit the rotational force of the drive source to the main shaft 106 via a V-belt.

[0022] In each sub-shaft 109, in order to enhance the wear resistance of the structural components, as shown in the illustrated embodiment, a cylindrical collar 111 is fitted with a slight clearance. Further, a plurality of ring-shaped members 112 are rotatably mounted as grinding media on each sub-shaft 109 via the fitted collar 111. The inner diameter of each ring-shaped member 112 is sufficiently larger than the outer diameter of the collar 111, and the ring-shaped member 112 is structured to have a sufficient gap between the inner peripheral surface of the ring-shaped member 112 and the outer peripheral surface of the collar 111 when the outer peripheral surface of the ring-shaped member 112 abuts against the inner peripheral surface 105 of the container 101. Also, the ring-shaped members 112 are not densely laminated without a gap between the two pressing plates 107 and 108, but are laminated so as to form a gap equivalent to the thickness of 2 to 3 sheets of the ring-shaped members 112 between the upper end surface of the laminated ring-shaped members 112 and the lower surface of the pressing plate 107. Due to this laminated structure, each ring-shaped member 112 can freely rotate around the collar 111.

[0023] The above-mentioned ring-shaped member 112 is formed in a cylindrical shape having parallel upper and lower surfaces, and is formed in a so-called washer shape with smooth upper and lower surfaces and an outer peripheral surface. Also, if necessary, the outer peripheral surface may be formed in a curved surface shape in order to promote the phenomenon of biting into the object to be processed. The size of the ring-shaped member 112 as this grinding medium varies depending on the type (size) of the processing apparatus, but the outer diameter is 25 to 45 mm and the thickness is about several mm. Also, the material thereof varies depending on the physical properties of the object to be processed, and is formed from stainless steel, ceramic materials such as alumina and zirconia, cemented carbide such as WC, and the like.

[0024] On the main shaft 106 located at the lower part of the lower pressing plate 108 and the upper part of the upper pressing plate 107, as necessary, as shown in the illustrated embodiment, stirring blades 113 and 114 for stirring the slurry-like object to be processed introduced into the container 101 are respectively disposed. In addition, in order to prevent the temperature rise of the slurry-like processed material when the pulverization process is carried out, the side surface of the container 101 is covered with a jacket 115, and a refrigerant supply port 116 and a discharge port 117 are provided in this jacket 115. By continuously supplying various refrigerants into this jacket 115, the slurry-like processed material introduced into the container 101 can be cooled.

[0025] In the pulverizer 100 having the above-described configuration, a gap is formed between the outer diameter of the sub-shaft 109 (the outer diameter of the cylindrical collar 111) and the inner diameter of the ring-shaped member 112 fitted to the sub-shaft 109 (the cylindrical collar 111). The ring-shaped member 112 is configured to be individually independent and freely rotatable. The ring-shaped member 112 having the function as the pulverizing medium moves radially by an amount corresponding to the above gap due to the centrifugal force generated as the main shaft 106 rotates, and orbits inside the container 101 while being pressed against the inner peripheral surface 105 of the container. Further, due to friction with the inner peripheral surface 105 and the like, the ring-shaped member 112 itself also rotates around the sub-shaft 109. That is, the ring-shaped member 112 becomes a complex one that moves inside the container 101 while repeating revolution and rotation. Therefore, when the slurry-like processed material is continuously supplied from the supply port 103 provided at the lower part of the container 101, the slurry-like processed material supplied into the container 101 is pushed from below and rises while receiving the compressive force and shear force of the above-described complexly rotating ring-shaped member 112, and is efficiently pulverized and continuously discharged from the discharge port 104 provided at the upper part of the container 101.

[0026] As shown in FIG. 1, an external circulation path portion 200 is connected to the discharge port 104 of the pulverizer 100. This external circulation path portion 200 has an action as a path for circulating the slurry-like processed material outside the pulverizer 100 and an action of increasing the processing amount. Therefore, it is preferable that the external circulation path portion 200 has a certain volume. In the embodiment shown in FIGS. 1 to 3, from the viewpoint of increasing the processing amount and the like, the external circulation path portion 200 includes an external tank 201.

[0027] The external tank 201 includes an internal space 202 for temporarily storing the slurry-like processed material, a supply port 203 for supplying the slurry-like processed material to the internal space 202, and a discharge port 204 for discharging the slurry-like processed material to the outside of the internal space 202. In the illustrated embodiment, the internal space 202 is formed in a cylindrical shape having an elliptical cross-sectional shape extending along the vertical direction. The supply port 203 is formed in a cover plate that closes the upper end, and the lower open end is the discharge port 204.

[0028] The open end of a pipe 205 connected to the discharge port 104 of the pulverizing device 100 is connected to the supply port 203 of the external tank 201. The slurry-like processed material pulverized by the pulverizing device 100 is supplied to the internal space 202 of the external tank 201 through the pipe 205, temporarily stored, and then discharged from the discharge port 204 which is the lower open end. The volume of the external tank 201 varies depending on the physical properties of the slurry-like processed material, but is determined from the balance between the processing amount and the pulverizing efficiency, etc. In the circulating pulverizing treatment device 1 according to the illustrated embodiment, the volume of the external tank 201 is designed to be preferably 5 times or more, more preferably 10 times or more the volume of the pulverizing device 100 (the volume excluding the rotating mechanism).

[0029] The slurry-like processed material discharged from the discharge port 204 of the external circulation path section 200 is conveyed to the supply port 103 of the pulverizing device 100 by a screw feeder 300. As shown in FIG. 1, the screw of the screw feeder 300 is arranged from the discharge port 204 of the external circulation path section 200 to the supply port 103 of the pulverizing device 100, and the slurry-like processed material is forcibly conveyed from the external circulation path section 200 to the pulverizing device 100 by the rotation of the screw.

[0030] As shown in FIGS. 1 to 3, the screw feeder 300 is formed as a two - shaft screw having a pair of screw shafts 301 and 302 arranged in parallel along the horizontal direction. It includes bearings 303 and 304 that rotatably support the pair of screw shafts 301 and 302 respectively, a casing 305 that extends along the horizontal direction and houses the pair of screw shafts 301 and 302, and a drive mechanism 306 that rotates the pair of screw shafts 301 and 302.

[0031] As shown in FIG. 7, each of the pair of screw shafts 301 and 302 includes shafts 307 and 308 that extend along the axis LA (LA1, LA2) and are rotatable, and screw blades 309 and 310 that are spirally provided on the outer peripheries of the shafts 307 and 308. As shown in FIG. 6, in the casing 305 that houses the pair of screw shafts 301 and 302, openings 311 and 312 are formed at positions corresponding to the discharge port 204 of the external circulation path portion 200 and the supply port 103 of the pulverizing device 100 respectively. As shown in FIG. 1, the drive mechanism 306 rotates the shafts 307 and 308 of the pair of screw shafts 301 and 302 respectively, as indicated by the arrows in FIGS. 3 and 7, inwardly towards each other when viewed from above.

[0032] As shown in FIGS. 6 and 7, at least one of the pair of screw shafts 301 and 302, that is, the screw shaft 302, has its tip end extending further downstream than directly below the supply port 103 of the pulverizing device 100. The screw blades 310 of the screw shaft 302 are formed in the feeding direction up to immediately before the supply port 103 of the pulverizing device 100, are not formed directly below the supply port 103, and are formed in the return direction on the downstream side of the supply port 103.

[0033] The pair of screw shafts 301 and 302 are cantilever structures supported by bearings 303 and 304 on the drive mechanism 306 side respectively. Even when a force is applied in a direction perpendicular to the rotation axis, it is necessary to prevent the screw blades 309 and 310 on the tip side of the screw shaft from hitting the casing 305 that covers the periphery thereof. For this purpose, bearings for supporting the tips of the screw shafts 301 and 302 may be provided. However, in the screw feeder 300, before the screw blades 309 and 310 hit the casing 305, the clearances between the two are narrowed so that the tips of the screw shafts 301 and 302 hit brackets or the like provided on the casing. Providing such a structure directly below the supply port 103 is not preferable for transporting the slurry-like processed material. Therefore, the screw tip has a positional relationship that extends further than the supply port 103 of the pulverizing device 100. Also, no screw blade 310 is formed directly below the supply port 103, and the screw blade 310 is formed in the return direction on the downstream side of the supply port 103. Thus, the slurry-like processed material moving toward the screw tip side is pushed back by the screw blade 310 formed in the return direction, and the slurry-like processed material is effectively pushed into the supply port 103 of the pulverizing device 100, preventing the slurry-like processed material from staying.

[0034] By using the screw feeder 300 configured as described above, as shown in FIG. 6, the slurry-like processed material discharged from the discharge port 204 of the external circulation path section 200 is supplied from the upstream opening 311 in the transfer direction A formed in the casing 305 into the internal space of the feeder, caught in the gaps between the pitches of the rotating screw blades 309 and 310, and conveyed toward the downstream side. The slurry-like processed material conveyed to the downstream side in the transfer direction A is discharged to the outside from the downstream opening 312 formed in the casing 305 and is charged into the pulverizing device 100 in a state of being pushed into the pulverizing device 100 from the supply port 103.

[0035] The conveying capacity of the screw feeder 300 varies depending on the processing capacity of the pulverizing device 100 and the physical properties of the slurry-like processed material to be conveyed. However, it is determined from the balance between the processing amount and the pulverizing efficiency. In the circulating pulverizing treatment apparatus 1 according to the illustrated embodiment, the conveying capacity of the screw feeder 300 is adjusted by adjusting the size and pitch of the screw blades 309 and 310, the rotational speed of the shaft, etc. As the volume of the slurry-like processed material conveyed per unit time, it is preferably designed to be 50 to 1000 ml / min, more preferably 100 to 1000 ml / min.

[0036] In the circulating pulverizing treatment apparatus 1 according to the present invention described above, as the pulverizing device 100, a supply port 103 for the slurry-like processed material is provided at the lower part of the container 101, and a rotating main shaft 106 is vertically provided inside the container 101. A plurality of sub-shafts 109 are circumferentially supported on the main shaft 106 at intervals. A plurality of ring-shaped members 112 are fitted to the sub-shafts 109 with a gap therebetween, and the ring-shaped members 112 are arranged so as to contact the inner wall 105 of the container. In addition, a discharge port 104 for the slurry-like processed material is provided at the upper part of the container 101. Therefore, the slurry-like processed material continuously supplied from the supply port 103 provided at the lower part of the container 101 is efficiently pulverized by receiving the compressive force and shear force of the ring-shaped member 112 that rotates complexly while being pushed upward from below in the container 101, and is continuously discharged from the discharge port 104 provided at the upper part of the container 101. Even for a high-viscosity slurry-like processed material with a high solid content concentration, the processed material can be efficiently pulverized. In addition, the circulating pulverization treatment apparatus 1 according to the present invention includes an external circulation path portion 200 for a slurry-like processed material connected to the discharge port 104 of the pulverization apparatus 100, and a screw feeder 300 that conveys the slurry-like processed material discharged from the discharge port 204 of the external circulation path portion 200 to the supply port 103 of the pulverization apparatus 100. The screw feeder 300 is arranged from the discharge port 204 of the external circulation path portion 200 to the supply port 103 of the pulverization apparatus 100, and the slurry-like processed material is circulated in the order of the pulverization apparatus 100, the external circulation path portion 200, and the screw feeder 300 for pulverization treatment. Therefore, the slurry-like processed material is circulated without separation of water or the like, which is a dispersion medium, and the solid content (processed material), which was a concern in an apparatus configured for pump conveyance, and the pulverization treatment of the solid content (processed material) surely proceeds. In addition, the stirring blades 113 and 114 for stirring the slurry-like processed material introduced into the container 101 cause the slurry-like processed material to circulate without creating a dead space in the container 101.

[0037] As described above, the circulating pulverization treatment apparatus 1 according to the present invention can stably perform the circulating pulverization treatment of the slurry-like processed material having a circulation path from the initial stage to over time.

[0038] The circulating pulverization treatment apparatus 1 according to the present invention described above is suitable for the circulating pulverization treatment of a high-concentration slurry-like processed material. Here, the ratio of the solid content (processed material) of the slurry-like processed material varies depending on physical properties such as the particle size, true density, and shape of the solid content (processed material). In the case of plant-based biomass, it is preferably in the range of 3 to 15% by mass, and more preferably in the range of 5 to 12% by mass. This is because when the concentration is less than 3% by mass, it does not lead to an improvement in treatment efficiency compared to the prior art, and when the concentration of plant-based biomass exceeds 15% by mass, the viscosity is too high. In addition, examples of the material to be subjected to the circulation pulverization treatment using the circulation pulverization treatment apparatus 1 according to the present invention include materials that are particularly easy to separate from a dispersion medium such as water, and for example, plant-based biomass. Here, examples of the plant-based biomass include woody, herbaceous, and cellulose-based materials. Examples of the woody and herbaceous materials include plant materials such as wood, bamboo, hemp, herbs, agricultural products, etc., wastes of the plant materials, and residues (bark, leaves, stems, fruits), etc. Examples of the cellulose-based materials include non-wood pulp made from wood pulp, straw, bagasse, cotton, hemp, kenaf fiber, etc., and deinked pulp (DIP) made from recovered waste paper, waste paper, etc. The woody, herbaceous, and cellulose-based biomasses are common in that they all contain cellulose.

[0039] From the above, the circulation pulverization treatment apparatus 1 according to the present invention can be suitably used as a circulation pulverization treatment method for circulating and pulverizing a slurry-like material of plant-based biomass using the circulation pulverization treatment apparatus 1, as a method for producing alcohol in which a slurry-like material of plant-based biomass is circulated and pulverized using the circulation pulverization treatment apparatus 1 and the obtained pulverized material is saccharified and fermented, and further as a method for producing a composition containing cellulose fibers in which a slurry-like material of plant-based biomass is circulated and pulverized using the circulation pulverization treatment apparatus 1.

Example

[0040] 1. Pulverization treatment of woody materials 〔Example 1〕 (1) Material to be treated As the material to be treated, commercially available cedar sawdust from the Kanto region and other places, which is for gardening and pets, was used. The central particle size of this cedar sawdust was 0.5 to 1.0 mm as measured by the particle size distribution using a sieve. Also, many of them had a large needle-like aspect ratio, and some had a length of about 2 to 3 mm. (2) Preparation of the material to be treated Water was added to the powder of the above woody material to prepare two types of slurry-like materials with a solid content concentration of 10% by mass and a solid content concentration of 15% by mass. (3) Pulverization treatment using a pulverizer

[0041] [Example 1-1] Using the circulating pulverization processing apparatus 1 according to the embodiment of the present invention shown in FIGS. 1 to 7, the circulating pulverization processing of the slurry-like processed material with the adjusted solid content concentration of 10% by mass was performed. As the pulverizer 100, Micro S0 type (MIC-0, volume excluding the rotation mechanism is 0.4 liter) manufactured by Nara Machinery Co., Ltd. was used. The external tank 201 has a volume of 0.3 liter, and the screw feeder 300 has a diameter including the screw blades of 14 mm. Pulverization was performed under the following processing conditions. (Processing conditions) · Slurry-like processed material charging amount: 0.500 kg · Total amount of solid content (processed material): 0.050 kg · Rotation speed of the pulverizer: 1500 rpm · Rotation speed of the screw feeder: 50 rpm · Conveying capacity of the screw feeder: 100 ml / min

[0042] [Example 1-2] Using the circulating pulverization processing apparatus 1 according to the embodiment of the present invention shown in FIGS. 1 to 7, the circulating pulverization processing of the slurry-like processed material with the adjusted solid content concentration of 10% by mass was performed. However, the external tank 201 was changed to one with a volume of 3 liters, and the same apparatus as in the above [Example 1-1] was used for the others, and pulverization was performed under the following processing conditions. (Processing conditions) · Slurry-like processed material charging amount: 2.500 kg · Total amount of solid content (processed material): 0.250 kg · Rotation speed of the pulverizer: 1500 rpm · Rotation speed of the screw feeder: 50 rpm · Conveying capacity of the screw feeder: 100 ml / min

[0043] [Example 1-3] Using the circulating pulverization processing apparatus 1 according to the embodiment of the present invention shown in FIGS. 1 to 7, the circulating pulverization processing of the slurry-like processed material with the adjusted solid content concentration of 15% by mass on the other side was performed. As the pulverizing device 100, a MIC-0 type (MIC-0, volume excluding the rotating mechanism is 0.4 liters) manufactured by Nara Machinery Co., Ltd. was used. The external tank 201 has a volume of 3 liters. A device similar to the above [Example 1-2] with a screw diameter of 14 mm including the screw blades of the screw feeder 300 was used, and pulverization was performed under the following processing conditions. (Processing conditions) · Charge amount of slurry-like processed material: 2.500 kg · Total amount of solid content (processed material): 0.375 kg · Rotation speed of the pulverizing device: 1500 rpm · Rotation speed of the screw feeder: 50 rpm · Conveying capacity of the screw feeder: 100 ml / min

[0044] [Example 1-4] Using the circulating pulverization processing device 1 according to the embodiment of the present invention shown in FIGS. 1 to 7, the circulating pulverization processing of the slurry-like processed material with the adjusted solid content concentration of 10% by mass was performed. As the pulverizing device 100, a MIC-3 type (MIC-3, volume excluding the rotating mechanism is 3.0 liters) manufactured by Nara Machinery Co., Ltd. was used. The external tank 201 has a volume of 24 liters. A device with a screw diameter of 28 mm including the screw blades of the screw feeder 300 was used, and pulverization was performed under the following processing conditions. (Processing conditions) · Charge amount of slurry-like processed material: 40.0 kg · Total amount of solid content (processed material): 4.00 kg · Rotation speed of the pulverizing device: 1100 rpm · Rotation speed of the screw feeder: 50 rpm · Conveying capacity of the screw feeder: 800 ml / min

[0045] [Comparative Example 1-1] A device similar to the above [Example 1-1] was used, except that the screw feeder in the above [Example 1-1] was replaced with a pump (Mono Pump CY type manufactured by Heishin Sobi Co., Ltd.). The slurry-like processed material with the adjusted solid content concentration of 10% by mass was subjected to circulating pulverization processing under the same processing conditions as in the above [Example 1-1].

[0046] [Comparative Example 1-2] The same apparatus as in [Example 1-1] above was used, except that the grinding device of [Example 1-1] above was changed to a bead mill (vessel volume: 1.0 liter, bead filling amount: 608 ml (2300 g)), and the screw feeder was changed to a pump (manufactured by Heishin Sozai Co., Ltd., Mono Pump CY type). The slurry-like processed material with a solid content concentration of 10% by mass adjusted above was first subjected to a circulation grinding process under the same processing conditions as in [Example 1-1] above. However, when the slurry-like processed material with a solid content concentration of 10% by mass was charged and the rotation speed of the bead mill was gradually increased, abnormal noise occurred in the bead mill at 120 rpm, so the test was aborted. Therefore, the solid content concentration of the slurry-like processed material was reduced to 1% by mass, and the bead mill was processed at a rotation speed of 20,000 rpm. The total amount of the solid content (processed material) at this time was 0.005 kg.

[0047] [Comparative Example 1-3] Using only the grinding device 100 shown in FIGS. 4 and 5, a batch-type grinding process was performed on the slurry-like processed material with a solid content concentration of 10% by mass adjusted above. The grinding device 100 was manufactured by Nara Machinery Co., Ltd., and Micro-S 0 type (MIC-0, volume excluding the rotation mechanism: 0.4 liter) was used, and grinding was performed under the following processing conditions. (Processing conditions) · Slurry-like processed material charging amount: 0.250 kg · Total amount of solid content (processed material): 0.025 kg · Rotation speed of the grinding device: 1500 rpm

[0048] [Comparative Example 1-4] Using only the grinding device 100 shown in FIGS. 4 and 5, the slurry-like processed material with a solid content concentration of 10% by mass adjusted above was subjected to a batch-type grinding process twice. The grinding device 100 was the same Micro-S 0 type (MIC-0, volume excluding the rotation mechanism: 0.4 liter) manufactured by Nara Machinery Co., Ltd. as in [Comparative Example 1-3], and grinding was performed under the following processing conditions. (Processing conditions) · Slurry-like processed material charging amount: 0.250 kg · Solid content (processed material) amount: 0.025 kg · Rotation speed of the pulverizer: 1500 rpm Process two batches under the above conditions · Total solid content (processed material) amount: 0.050 kg

[0049] 〔Comparative Example 1-5〕 Using only the pulverizer 100 shown in FIGS. 4 and 5, a batch-type pulverization treatment was performed 10 times on the slurry-like processed material with the adjusted solid content concentration of 10% by mass. The pulverizer 100 is of the type manufactured by Nara Machinery Co., Ltd. similar to that in 〔Comparative Example 1-3〕, the Micro S0 type (MIC-0, the volume excluding the rotation mechanism is 0.4 liters), and pulverization was performed under the following processing conditions. (Processing conditions) · Charge amount of the slurry-like processed material: 0.250 kg · Total solid content (processed material) amount: 0.025 kg · Rotation speed of the pulverizer: 1500 rpm Process 10 batches under the above conditions · Total solid content (processed material) amount: 0.250 kg

[0050] Regarding the above 〔Example 1-1〕 to 〔Example 1-4〕 and 〔Comparative Example 1-1〕 to 〔Comparative Example 1-5〕, the yield, the time until the median diameter (d50) of the processed material reaches 7 μm ± 0.3 μm (total pulverization time), the equipment production capacity obtained by dividing the yield by the total working time, etc. are described in Table 1.

[0051]

Table 1

[0052] As shown in Table 1, in 〔Example 1-1〕 using a screw feeder as the conveying means, the total pulverization time was shortened to 40% or less compared to 〔Comparative Example 1-1〕 using a mono pump. The equipment production capacity obtained by dividing the yield by the total working time was "0.0129" and "0.0062" for 〔Example 1-1〕 and 〔Comparative Example 1-1〕 respectively, and was improved by 2.1 times. In [Comparative Example 1-2] using a bead mill, since the solid content concentration was reduced to 1% by mass for treatment, the equipment production capacity obtained by dividing the yield by the total working time was "0.0009". In [Example 1-1], the equipment production capacity obtained by dividing the yield by the total working time was "0.0129", which was 1.35 times and 1.2 times higher respectively compared to "0.0095" in [Comparative Example 1-3] which is a conventional batch process and "0.0108" in [Comparative Example 1-4] where the same charge amount was processed batchwise. As shown in Table 1, [Example 1-2] which used an external circulation path to increase the throughput by 10 times had less switching loss and a yield of 96%, while [Comparative Example 1-5] with the same throughput had a yield of 80%. In [Example 1-2], the equipment production capacity obtained by dividing the yield by the total working time was "0.0197", which was 1.6 times higher compared to "0.0121" in [Comparative Example 1-5] where the same charge amount was processed batchwise. As can be seen from the comparison between [Example 1-1], [Example 1-2], and [Comparative Example 1-3] to [Comparative Example 1-5], the equipment production capacity of the examples is higher than that of the comparative examples where the same charge amount was processed batchwise, and the greater the charge amount using the external circulation path, the greater the degree of improvement. In [Example 1-3], even when the solid content concentration was increased to 15%, the equipment production capacity was equivalent to that of [Example 1-2]. [Example 1-1] to [Example 1-4] were capable of long-term continuous operation processing, and the operator's response time, excluding the measurement of particle size, was only 1 hour for pre- and post-cleaning. In [Example 1-2], the raw materials were set and the operation of the circulation processing equipment was started, and the processing was completed in approximately 12 hours of total working time. The operator was released from the work and could perform other tasks, excluding the measurement of particle size immediately before the end. [Comparative Example 1-5] where the same charge amount was processed batchwise had a total working time spanning more than 16 hours and the work had to be carried out in two days. During this period, the operator performed batch switching operations for 30 minutes every about 1 hour. In addition, in [Example 1-4] where the processing device was changed to one with a volume of 3.0 liters excluding the rotating mechanism, 40 kg of a slurry-like processed material with a solid content concentration of 10% by mass (4 kg of wood material) could be processed in a total working time of 21 hours.

[0053] 2. Ethanol production [Example 2] Circulation treatments were respectively carried out in the same manner as in [Example 1-1] to [Example 1-4], [Comparative Example 1-3], except that the slurry-like processed material subjected to the following alkali treatment was used as the processed material, and the wood slurries of [Example 2-1] to [Example 2-4], [Comparative Example 2-3] were respectively obtained. [Alkali treatment] A slurry of a wood material with a solid content concentration of 10% by mass was put into a commercially available autoclave, and then alkaline water was added to adjust the pH to 2. Immersion treatment was carried out at 120 °C for 4 hours without stirring while heating under pressure. [Circulation pulverization treatment] Circulation treatments were respectively carried out in the same manner as in [Example 1-1] to [Example 1-4], [Comparative Example 1-3]. [Saccharification and fermentation conditions] For the obtained wood slurries of [Example 2-1] to [Example 2-4], 90 ml of distilled water was added to 50 g of the collected wood slurry for dilution and transferred to an Erlenmeyer flask with a baffle. Then, a suspension of enzymes manufactured by Novozymes (1.3 ml of Ctec2 and 400 μl of Htec2) suspended in 7.70 ml of distilled water was added. After covering the flask with aluminum foil, shaking was carried out in a shaking thermostatic bath at a temperature of 50 °C for 48 hours for saccharification treatment. The obtained saccharified solution was adjusted to pH 6.5, sterilized with a sterile filter with a pore size of 0.45 μl, put into a 1-liter graduated cylinder, and further, the pre-cultured yeast SS4-5 was inoculated at a concentration of 1.0×107 cells / ml, and fermentation was carried out at 30 °C for 3 days. Note that yeast SS4-5 is a yeast of Schizosaccharomyces japonicus SS4-5 strain with an accession number of NITE P-1197.

[0054] For each of [Example 2-1] to [Example 2-4] that had undergone the above saccharification and fermentation treatments, the Glc production concentration and the amount of alcohol obtained were measured. The measurement results are shown in Table 2. Also, as [Comparative Example 2-3], for the lignin slurry that had undergone the above alkali treatment as the material to be treated and that had been subjected to pulverization treatment in the same manner as [Comparative Example 1-3] described above, the Glc production concentration and the amount of alcohol obtained after the above saccharification and fermentation treatments were measured. The measurement results are shown in Table 2. As shown in Table 2, compared with the conventional method, a large amount of alcohol could be produced in a single treatment.

[0055]

Table 2

[0056] 3. Cellulose Fiber Production 〔Example 3〕 A commercially available softwood bleached kraft pulp (N-BKP, manufactured by Oji Paper Co., Ltd., solid content concentration 25% by mass) was diluted with water to prepare a slurry-like material with a solid content concentration of 10% by mass. This prepared slurry-like material was subjected to a circulation defibering treatment under the following treatment conditions using the circulation pulverization treatment apparatus 1 according to the embodiment of the present invention shown in FIGS. 1 to 7 (the pulverization apparatus 100 is manufactured by Nara Machinery Co., Ltd., Micro-S 0 type (MIC-0, volume excluding the rotation mechanism is 0.4 liters), volume of the external tank 201 is 3 liters, diameter including the screw blades of the screw feeder 300 is 14 mm). (Treatment Conditions) · Slurry-like material charged amount 5.0 kg (solid content 0.5 kg) · Rotation speed of the pulverization apparatus 1800 rpm · Rotation speed of the screw feeder 45 rpm · Conveying capacity of the screw feeder 80 ml / min

[0057] When the above defibering treatment was carried out, the pulp could be circulated without separation. After 10 minutes of treatment, the slurry-like treated product was washed three times with butanol, dried with a freeze dryer, and then the specific surface area was determined by the nitrogen gas adsorption method. As a result, the specific surface area was 92 m 2 / g. Also, after 30 minutes of treatment, the slurry-like treated product was washed three times with butanol, dried with a freeze dryer, and then the specific surface area was determined. The specific surface area was 132 m 2 / g. As described above, it was confirmed that fibrillation of the cellulose contained in the pulp was progressing.

Industrial Applicability

[0058] The circulating pulverization treatment apparatus according to the present invention can be suitably used as an apparatus for pulverizing plant biomass to produce ethanol, or as an apparatus for defibrating pulp to produce cellulose fibers.

Explanation of Signs

[0059] 1 ··· Circulating pulverization treatment apparatus 100 ··· Pulverizer 101 ··· Container, 102 ··· Rotating mechanism, 103 ··· Supply port, 104 ··· Discharge port, 105 ··· Inner peripheral surface, 106 ··· Main shaft, 107 ··· Pressing plate, 108 ··· Pressing plate, 109 ··· Sub-shaft, 110 ··· Nut, 111 ··· Collar, 112 ··· Ring-shaped member, 113 ··· Stirring blade, 114 ··· Stirring blade, 115 ··· Jacket, 116 ··· Supply port, 117 ··· Discharge port 200 ··· External circulation path section 201 ··· External tank, 202 ··· Internal space, 203 ··· Supply port, 204 ··· Discharge port, 205 ··· Pipe 300 ··· Screw feeder 301 ··· Screw shaft, 302 ··· Screw shaft, 303 ··· Bearing, 304 ··· Bearing, 305 ··· Casing, 306 ··· Driving mechanism, 307 ··· Shaft, 308 ··· Shaft, 309 ··· Screw blade, 310 ··· Screw blade, 311 ··· Opening, 312 ··· Opening, 3013 ··· Motor, 314 ··· Gear train

Claims

1. a crushing device having a supply port for a slurry-like material to be treated provided at a lower portion of a container, a rotating main shaft provided upright inside the container, a plurality of sub-shafts circumferentially supported by the main shaft at intervals, a plurality of ring-shaped members fitted on the sub-shafts with gaps provided between the sub-shafts, the ring-shaped members being disposed so as to abut against an inner wall of the container, and a discharge port for the slurry-like material provided at an upper portion of the container; an external circulation path portion for a slurry-like treated material connected to the discharge port of the pulverizing device; a screw feeder that conveys the slurry-like treated product discharged from the discharge port of the external circulation path section to the supply port of the grinding device, the screw feeder is disposed between a discharge port of the external circulation path section and a supply port of the grinding device, The slurry-like treatment product is circulated through the grinding device, the external circulation path section, and the screw feeder in this order to perform the grinding treatment. Circulating grinding processing equipment.

2. 2. The circulating grinding and treatment device according to claim 1, wherein the external circulation path portion includes an external tank.

3. 3. The circulating grinding processing device according to claim 1, wherein the tip of the screw feeder extends further downstream than immediately below the supply port of the grinding device, and the screw blades of the screw feeder are formed in the feed direction up to immediately before the supply port of the grinding device, are not formed immediately below the supply port, and are formed in the return direction downstream of the supply port.

4. 4. The circulation crushing processing device according to claim 1, wherein the screw feeder is formed as a twin screw.

5. A circulatory grinding method, comprising circulating and grinding a slurry-like treated product of plant biomass using the circulatory grinding treatment device according to any one of claims 1 to 4.

6. The circulation and grinding method according to claim 5, wherein the slurry-like treated material is a slurry of plant biomass having a solid content of 3 to 15 mass %.

7. 7. The method for circulating and grinding the wastewater treatment material according to claim 5, wherein the plant biomass is any one of woody, herbaceous, and cellulosic biomass.

8. A method for producing alcohol, comprising: using the circulating grinding treatment device according to any one of claims 1 to 4 to circulate and grind a slurry-like treated product of plant biomass; and saccharifying and fermenting the resulting ground product.

9. A method for producing a composition containing cellulose fiber, comprising circulating and pulverizing a slurry-like treated product of plant biomass using the circulating and pulverizing treatment device according to any one of claims 1 to 4.

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