JP2012000527A - Device and method for dehydrating biomass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device and a method for efficiently dehydrating biomass material such as bagasse after washing by preventing blocking of a filter medium due to fiber.SOLUTION: The biomass dehydrating device including a dehydration treatment tank having a bottom surface with a semi-circular cross section and a screw 14 close to the bottom surface is used. The bottom surface 13 of the dehydration treatment tank 11 is provided with a dehydration filtrating part 31, and a peripheral edge of a blade 16 of the screw 14 is provided with a plurality of notches 61 or projections 71. Biomass is supplied from one end part of the dehydration treatment tank and is discharged from the other end part by rotation of the screw to carry out dehydration treatment.

Description

  The present invention relates to an apparatus and a method for dewatering a biomass material after washing.

  Biomass such as bagasse, wheat straw, rice straw, and palm residue is used as livestock feed as well as industrial raw materials such as alcohol. Many foreign materials such as gravel are mixed in these biomass raw materials obtained locally, and the foreign materials are removed by washing at the initial stage of the treatment process in order to prevent wear of the equipment. The washing of the biomass raw material is usually performed by adding water to the biomass and stirring to loosen the fiber entanglement including gravel and the like. The washed biomass containing a large amount of moisture needs to be dehydrated in order to reduce its moisture before subsequent steps.

  Conventionally, dehydration of biomass has been performed by a screen, a trommel or the like. However, if the screen and trommel are rough, pis useful as a raw material is discharged together with the filtrate, resulting in a problem that the yield of biomass is lowered. Further, if the eyes are made finer, it is easy to cause clogging by the fiber, and it is necessary to provide a separate clogging removing means or to periodically exchange and clean the filter medium.

  In Patent Document 1, in a screw type dehydrator, a blade of a screw installed inside a rotating screen is in contact with an inner wall of the screen, and the blade rotates at a high speed from the screen, so that the blade is scraped. And a pulp dewatering machine having a self-cleaning function of eliminating clogging of the screen with pulp. However, when such a dehydrator is used, there is a problem that abrasion is likely to occur due to contact between the blade and the screen, and frequent replacement of the blade or the screen is required.

JP 2000-500179 A

  SUMMARY OF THE INVENTION The main problem to be solved by the invention is to provide a dehydration apparatus and method for efficiently dehydrating biomass without being affected by the blockage of the filter medium with fibers.

The present invention that has solved this problem is as follows.
<Invention of Claim 1>
A biomass dehydration apparatus comprising a dehydration tank having a bottom surface with a semicircular cross-section, and a screw close to the inside of the bottom surface,
A dehydration filtration unit is formed on the bottom surface of the dehydration tank,
A plurality of notches or protrusions are formed on the periphery of the blade of the screw,
The biomass supplied from one end of the dehydration tank is discharged from the other end by rotation of the screw and is configured to be dehydrated.
A biomass dehydration apparatus characterized by that.

(Function and effect)
By using a screw-type dehydrator as the biomass dehydrator, it is possible to transport the biomass simultaneously with dehydration and to perform continuous operation. The screw-type dewatering device has a configuration in which the bottom surface of the dewatering tank is semicircular and the bottom surface is close to the screw blade.

  In the present invention, the screw blade is provided with a notch or a protrusion. By putting biomass into such a dehydrator and rotating the screw, biomass fiber enters and remains between the notches or protrusions. By continuing the operation, the biomass remaining on the peripheral edge of the blade rubs against the bottom surface of the dehydration tank as the blade rotates. By placing a dewatering filter such as punching metal and wedge wire on the bottom of the dewatering tank, the part of the dewatering filter close to the screw blade is always in contact with the fibers of the biomass due to the rotation of the screw and sticking to that part. The fiber that causes the clogging can be removed from the filter medium by rubbing.

A method of removing the blockage of the dewatering filtration unit by bringing the blade into contact with the dewatering filtration unit is also disclosed in Patent Document 1, but in this method, since the blade itself is configured to positively contact the dehydration filtration unit, The blade peripheral part and the dewatering filter part are likely to be worn. In the present invention, most of the portions of the screw portion that come into contact with the dewatering filtration portion are portions into which flexible biomass has entered, and damage due to wear of the dewatering filtration portion can be reduced as compared with a hard material. . Even if the biomass lump formed on the peripheral edge of the blade collapses due to friction with the dewatering filtration unit, the biomass newly enters and forms a lump, so that replacement of the member or the like is not required. Further, by rubbing the dehydration filtration part with fibrous material, it is possible to achieve a higher obstruction removal effect than rubbing with the blade itself.
Thus, the present invention provides a dehydrating apparatus having a self-cleaning function.

<Invention of Claim 2>
The biomass dehydration apparatus according to claim 1, wherein the dehydration tank is inclined, configured to supply biomass from an inclined lower end and discharge biomass from an inclined upper end.

(Function and effect)
Most of the screw type dehydrating devices are horizontal, and the material is dehydrated by dropping moisture to the lower part of the device by gravity and compressing the material by rotating the screw. However, biomass, which is a dehydrating material in the present invention, has a low specific gravity, and in a horizontal dehydrating apparatus, it is unevenly distributed in the upper part of the dehydrating tank, and dehydration and compression by a screw are difficult to be performed efficiently. The dewatering efficiency can be improved by tilting the dehydration tank and sending biomass from below to above.

<Invention of Claim 3>
The biomass dehydration apparatus according to claim 1, wherein the dehydration filtration unit is partially arranged in a screw proximity portion on a bottom surface of the dehydration treatment tank.

(Function and effect)
Normally, the bottom of the screw-type dewatering device has a dehydration filtration part in whole or in part, but the dehydration filtration part is arranged only in the part close to the screw blade at the bottom of the device, so that dehydration can be achieved. It becomes possible to remove most of the blockage of the filtration part.

<Invention of Claim 4>
The length of the notch of the screw blade in the radial direction is 2.5 to 8.0% of the outer diameter of the screw, and the total length in the circumferential direction of the notch portion is 20% or more of the circumference. The biomass dehydration apparatus according to any one of claims 1 to 3, wherein the are arranged at substantially equal intervals, and the number of notches is 4 to 50 per round.

(Function and effect)
When notches are provided in the screw blades, the number and size of the screw blades are configured so as to be defined in the present invention, so that the biomass can efficiently enter the peripheral edge of the blades while maintaining the efficiency of stirring and conveying by the screws. A mass of quality can be formed.

<Invention of Claim 5>
The radial length of the protrusion of the blade of the screw is 2.5 to 8.0% of the outer diameter of the screw, and the total length in the circumferential direction of the protrusion is 20% or more of the circumference. The biomass dehydration apparatus according to any one of claims 1 to 3, wherein the biomass dehydration apparatus is arranged at substantially equal intervals, and the number of protrusions is 4 to 50 per round.

<Invention of Claim 6>
A biomass dehydration method using a biomass dehydration apparatus comprising a dehydration tank having a bottom surface of a semicircular cross section and a screw close to the inside of the bottom surface,
Disposing a dehydration filtration unit on the bottom of the dehydration tank,
A plurality of notches or protrusions are arranged on the periphery of the blade of the screw,
Biomass is supplied from one end of the dehydration tank, and dehydration is performed by discharging from the other end by rotation of the screw.
A method for dehydrating biomass.

  ADVANTAGE OF THE INVENTION According to this invention, by having a self-cleaning function, the apparatus which can perform dehydration of biomass efficiently, without being influenced by the obstruction | occlusion of the filter medium by fiber, and the dehydration of biomass using the said apparatus It is possible to provide a method.

It is a flowchart of a biomass treatment process. It is a front view of an example of a biomass dehydration device concerning the present invention. It is a bottom view of the bottom part filtration groove | channel of the dehydrator of FIG. It is a front view of the bottom part filtration groove | channel of the dehydrator of FIG. FIG. 3 is a cross-sectional view taken along line AA in FIG. 2. It is an enlarged view of the broken-line surrounding part B of FIG. It is another example of a form of FIG. (A) The notch has a rectangular shape, (B) the notch has a V-shape, and (C) has a protrusion. It is the schematic of the structure of the notch part which biomass entered. (A) Notch part perspective view, (B) Notch front view.

  FIG. 1 shows an outline of the biomass treatment process. Biomass such as bagasse is separated from foreign substances such as sand and pebbles by the cleaning process, and much of the water added in the cleaning process is removed by the dehydration process. The dehydrated biomass is transported by a transport means such as a screw feeder or a piston feeder, and is subjected to a saccharification step. In the saccharification step, saccharification by hydrolysis of cellulose or the like, which is the main component of biomass, or enzymatic saccharification is performed. The saccharified raw material is further processed into an organic fuel such as ethanol or an organic acid by fermentation. This invention relates to the apparatus and method which concern on the dehydration process of biomass among the said processes.

  The biomass in the present invention refers to soft biomass such as bagasse, wheat straw, rice straw, palm residue, corn stover, palm eggplant residue, cassava residue, piece of wood, wood waste, jute, kenaf, and waste paper. Specifically, the present invention can be particularly preferably applied to biomass having the properties shown in Table 1.

  FIG. 2 shows an example of a biomass dehydrator according to the present invention. The solid line arrows in FIG. 2 indicate the flow of biomass, and the broken line arrows indicate the flow of water. The dehydration treatment tank 11 of the biomass dehydrator 1 is preferably inclined by 10 to 45 degrees, more preferably 15 to 35 degrees from the horizontal direction. The washed biomass is charged into the dehydration tank 11 through the inlet 12 provided at the lower end of the inclined dewatering tank.

  A bottom filtration groove 13 having a semicircular cross section is disposed at the bottom of the dehydration tank 11. The screw 14 is arranged in the dehydration tank 11 so that the screw shaft 15 is substantially parallel to the longitudinal direction of the dehydration tank 11. The input biomass moves to the upper end of the dehydration treatment tank 11 while being dehydrated by the rotation of the screw shaft 15 and the screw blade 16 via the driving roller 17, is discharged from the discharge port 18, and is supplied to the next process. . On the other hand, moisture contained in the biomass passes through the bottom filtration groove 13 due to gravity and falls into the lower cover 19 and is discharged from the drainage drain 20.

  A bottom view of the bottom filtration groove 13 is shown in FIG. 3, and a front view is shown in FIG. As a material for the bottom filtration groove 13, it is preferable to use a metal material having sufficient rigidity such as stainless steel. The entire surface of the bottom filtration groove 13 may be a dehydration filtration unit, or the dehydration filtration unit 31 may be partially disposed in the vicinity of the screw blade. Specifically, as shown in FIGS. 3 (A) and 4 (A), a form in which the dewatering filtration unit 31 is provided only at the center portion in the width direction of the bottom filtration groove 13, FIGS. 3 (B) and 4 (B). ), The dehydration filtration unit 31 may be provided only on the start side.

  The dewatering filtration part 31 can arrange | position many holes to make a punching metal, or can attach well-known filter media, such as a wedge wire and a wire mesh, to the said part. As the filter medium, it is particularly preferable to use punching metal or wedge wire since it requires strength against biomass friction. When the dewatering filtration part is made of punching metal, the hole diameter is preferably 0.5 to 3.0 mm, particularly preferably 1.0 to 2.0 mm. In addition, when attaching a wedge wire, the wire material should be a metal material having sufficient rigidity such as stainless steel, and the slot size should be 0.5 to 3.0 mm, particularly 1.0 to 2.0 mm. preferable.

  FIG. 5 shows a cross-sectional view of the dehydrator 1 along the line AA. Furthermore, the enlarged view of the broken-line surrounding part B containing the screw 14 and the bottom part filtration groove | channel 13 is shown in FIG. The screw 14 is installed so that the rotational axis of the screw shaft 15 is positioned at substantially the center of the semicircle of the bottom filtration groove 13 having a semicircular cross section. The distance d between the peripheral end of the screw blade 16 (protrusion apex in the case where a protrusion is provided on the periphery) and the bottom filtration groove 13 is preferably about 2.0 to 3.0 mm.

  In the illustrated example, the screw blade 16 has a plurality of semicircular cutouts 61 at the peripheral edge thereof. The interval between the notches is preferably such that the central angle θ1 formed between the adjacent notches is 7 to 90 degrees, particularly 15 to 20 degrees. That is, it is preferable to provide 4 to 50 notches 61 per circuit. The length c in the radial direction of the blade of the notch 61 is preferably 2.5 to 8.0%, particularly 3.5 to 6.5% of the outer diameter of the blade. The total length e of the notches 61 in the blade circumferential direction is preferably 20% or more, particularly 50% or more of the circumference. If the size of the notch 61 is too large, the effect of screw dehydration is difficult to achieve. If it is too small, the biomass is difficult to enter and the self-cleaning function that is the object of the present invention is difficult to achieve.

  FIG. 8 shows a schematic view of the state where biomass enters the notch. As in the illustrated example, the fiber 80 penetrates through the front and back of the notch 61 (FIG. 8A), and remains so as to close the notch (FIG. 8B). In FIG. 8A, for the sake of convenience, the fiber is shown to be significantly thicker than the actual one and the cross-sectional shape is shown as being uniform, but is actually thin, the cross-section is indeterminate and sparse in size. The fiber may not only block the notch 61, but may also clog between the portion other than the notch of the screw and the filtration groove 13.

  Another example of the form of the screw blade 16 is shown in FIG. As shown in FIG. 7A and FIG. 7B, the shape of the notch 61 can be appropriately selected from shapes such as a rectangular shape and a V-shape. Further, as shown in FIG. 7C, a protrusion 71 may be provided on the peripheral edge of the blade. The protrusion 71 in the illustrated example illustrates a round pin shape, but the shape is not limited to a round pin shape, and a prismatic shape, a cone shape, or the like can be used as appropriate.

  When providing the protrusions, it is preferable that the interval between the protrusions 71 is such that the central angle θ2 formed between the adjacent protrusions is 7 to 90 degrees, particularly 15 to 20 degrees. That is, it is preferable to provide 4 to 50 protrusions 71 per round. The length of the protrusion 71 in the radial direction is preferably 2.5 to 8.0%, particularly 3.5 to 6.5% of the outer diameter of the blade. The total length of the protrusions 71 in the blade circumferential direction is preferably 20% or more, particularly 50% or more of the circumference.

  DESCRIPTION OF SYMBOLS 1 ... Biomass dehydration apparatus, 11 ... Dehydration processing tank, 12 ... Biomass inlet, 13 ... Bottom filtration groove, 14 ... Screw, 15 ... Screw shaft, 16 ... Screw blade, 17 ... Drive roller, 18 ... Biomass discharge port, 19 ... lower cover, 20 ... drainage drain, 31 ... dehydration filtration part, 61 ... notch part, 71 ... projection part.

Claims (6)

A biomass dehydration apparatus comprising a dehydration tank having a bottom surface with a semicircular cross-section, and a screw close to the inside of the bottom surface,
A dehydration filtration unit is formed on the bottom surface of the dehydration tank,
A plurality of notches or protrusions are formed on the periphery of the blade of the screw,
The biomass supplied from one end of the dehydration tank is discharged from the other end by rotation of the screw and is configured to be dehydrated.
A biomass dehydration apparatus characterized by that.   The biomass dehydration apparatus according to claim 1, wherein the dehydration tank is inclined, configured to supply biomass from an inclined lower end and discharge biomass from an inclined upper end.   The biomass dehydration apparatus according to claim 1, wherein the dehydration filtration unit is partially arranged in a screw proximity portion on a bottom surface of the dehydration treatment tank.   The length of the notch of the screw blade in the radial direction is 2.5 to 8.0% of the outer diameter of the screw, and the total length in the circumferential direction of the notch portion is 20% or more of the circumference. The biomass dehydration apparatus according to any one of claims 1 to 3, wherein the are arranged at substantially equal intervals, and the number of notches is 4 to 50 per round.   The radial length of the protrusion of the blade of the screw is 2.5 to 8.0% of the outer diameter of the screw, and the total length in the circumferential direction of the protrusion is 20% or more of the circumference. The biomass dehydration apparatus according to any one of claims 1 to 3, wherein the biomass dehydration apparatus is arranged at substantially equal intervals, and the number of protrusions is 4 to 50 per round. A biomass dehydration method using a biomass dehydration apparatus comprising a dehydration tank having a bottom surface of a semicircular cross section and a screw close to the inside of the bottom surface,
Disposing a dehydration filtration unit on the bottom of the dehydration tank,
A plurality of notches or protrusions are arranged on the periphery of the blade of the screw,
Biomass is supplied from one end of the dehydration tank, and dehydration is performed by discharging from the other end by rotation of the screw.
A method for dehydrating biomass.

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