JP5779323B2 - Pre-saccharification method for lignocellulosic biomass - Google Patents

Description

  The present invention relates to a saccharification pretreatment method for lignocellulosic biomass.

  Conventionally, a method of producing ethanol by saccharifying lignocellulosic biomass such as rice straw with a saccharifying enzyme produced by a microorganism and fermenting the obtained sugar as a substrate is known. Here, the lignocellulosic biomass has a structure in which lignin is firmly bound to cellulose or hemicellulose. Therefore, the saccharification pretreatment product obtained by pretreating the lignocellulosic biomass, dissociating lignin contained in the lignocellulosic biomass, or swelling the lignocellulosic biomass is used.

  In the present application, the term “dissociation” means that at least a part of the bond between cellulose or hemicellulose and lignin is broken. Further, the term “swelling” means that the crystalline cellulose expands by forming voids in the cellulose or hemicellulose constituting the crystalline cellulose by the intrusion of the liquid, or forming voids inside the cellulose fiber. .

  In the conventional method for producing ethanol, since the saccharifying enzyme is expensive, the amount of the saccharifying enzyme used is reduced by reducing the concentration of the substrate contained in the pre-saccharification product. However, when the concentration of the substrate contained in the pre-saccharification product is low, the saccharification solution obtained from such a saccharification treatment product also has a low concentration, and thus ethanol obtained by fermenting the saccharification solution has a low concentration. Become. As a result, when the obtained ethanol is distilled to concentrate, there is a problem that time and heat energy required for the distillation increase.

  In order to solve the above problem, it is conceivable to obtain a high concentration of ethanol by increasing the amount of the saccharification enzyme while increasing the concentration of the substrate contained in the pre-saccharification product. In this case, since the amount of the expensive saccharifying enzyme used increases and costs increase, it is necessary to reduce the overall cost of the ethanol production method.

  As one measure for reducing the cost in the ethanol production method, it is conceivable to improve the efficiency of pretreatment for saccharification of the lignocellulosic biomass.

  As a method for pretreatment of lignocellulosic biomass saccharification, for example, a method is known in which lignocellulosic biomass is mixed with liquid pure ammonia, heated and pressurized, and then the pressure is rapidly reduced. If it does in this way, when the vaporized ammonia gas is rapidly expanded, the lignocellulosic biomass is also expanded, and lignin is physically removed from the lignocellulosic biomass (see Patent Document 1).

  However, in order to use pure ammonia, a special device such as a pressure vessel for storage thereof is required. Therefore, it has been studied to use ammonia water in which pure ammonia is used as an aqueous solution.

  As a method of using the ammonia water, a method is known in which the lignocellulosic biomass is brought into contact with ozone and then immersed in ammonia water (see Patent Document 2). However, in this case, since a step of bringing the lignocellulosic biomass into contact with ozone is added, the cost cannot always be reduced.

  Moreover, the method of heating the mixture formed by mixing the said lignocellulosic biomass and ammonia water is known (refer patent document 3). According to the method described in Patent Document 3, the lignocellulosic biomass is dispersed in ammonia water having a concentration of 0.8 to 15% by weight and heated to dissociate lignin from the lignocellulosic biomass, or the It is said that lignocellulosic biomass can be swollen.

JP 2005-232453 A JP 57-5697 A Special table 2008-535524 gazette

  However, the method described in Patent Document 3 has a disadvantage in that it is necessary to dissociate lignin from the lignocellulosic biomass or to swell the lignocellulosic biomass.

  Therefore, the present invention eliminates such inconvenience and can dissociate lignin from the lignocellulosic biomass or swell the lignocellulosic biomass without heating, reducing the cost required for the saccharification pretreatment. It aims at providing the saccharification pre-processing method of lignocellulosic biomass which can be performed.

In order to achieve this object, the saccharification pretreatment method for lignocellulosic biomass according to the present invention comprises treating a substrate mixture obtained by mixing lignocellulosic biomass and ammonia water as a substrate to contain lignin contained in the substrate. In a pretreatment for saccharification of lignocellulosic biomass, in which a step of obtaining a pre-saccharification product by swelling the substrate or swelling the substrate and a step of separating ammonia from the pre-saccharification product Supplying the substrate and the ammonia water continuously to the substrate, stirring the substrate and the ammonia water supplied to the treatment tank to impart shearing force and impact force to the substrate, by mixing the said substrate, a step of obtaining a substrate mixture which is a Shimekonatai, said substrate mixture, or the processing tank to the interior of the reservoir which is disposed directly below the said processing tank While continuously discharging, the step of discharging ammonia gas and air from the storage tank, the substrate mixture discharged from the treatment tank is stored in the storage tank for a predetermined time, and in a non-heated state during storage The step of dissociating lignin contained in the substrate or swelling the substrate, and the saccharification pretreated product in which the lignin is dissociated or the substrate is swollen are continuously taken out from the storage tank, and immediately below the storage tank. The ammonia separation means disposed in the container is heated to vaporize and dissipate the ammonia, thereby separating the ammonia from the saccharification pretreatment product, and the saccharification pretreatment product from which ammonia has been separated, And a step of discharging from the ammonia separation means and transferring it to a subsequent step.

  According to the lignocellulosic biomass saccharification pretreatment method of the present invention (hereinafter sometimes abbreviated as saccharification pretreatment method), first, lignocellulosic biomass as the substrate, ammonia water, Is supplied continuously.

  Here, lignocellulosic biomass as the substrate is difficult to be uniformly impregnated with the ammonia water simply by mixing with the ammonia water, and heating to dissociate lignin by causing ammonia to act on such a substrate. Need.

On the other hand, in the saccharification pretreatment method of the present invention, the substrate and the ammonia water are continuously supplied to the treatment tank, and the ammonia water and the substrate are mixed by stirring. At this time, by applying a shearing force and an impact force to the substrate, it is possible to obtain a substrate mixture in which the ammonia water is uniformly impregnated into the substrate to form a wet powder .

In the saccharification pretreatment method of the present invention, next, the obtained substrate mixture is continuously discharged from the treatment tank and stored in the storage tank.
At this time, since the substrate mixture obtained in the treatment tank is a wet powder, when the treatment tank and the storage tank are connected by a pipe or the like, the wet powder causes a bridging phenomenon in the pipe. There is a concern that the pipe will be raised and closed.
Therefore, in the saccharification pretreatment method of the present invention, the storage tank is disposed immediately below the treatment tank, and the substrate mixture is continuously discharged from the treatment tank into the storage tank. As a result, in the saccharification pretreatment method of the present invention, the substrate mixture that is the wet powder can be supplied from the treatment tank to the storage tank without causing a bridging phenomenon.
In the storage tank, when the substrate mixture discharged from the treatment tank is supplied, air or ammonia gas is mixed, and the space inside the storage tank is effectively used for storing the substrate mixture. There is a concern that it will not be possible. Therefore, in the pre-saccharification pretreatment method of the present invention, by discharging ammonia gas and air from the storage tank, the internal space of the storage tank can be effectively used for storing the substrate mixture.
Next, the ammonia water is uniformly impregnated in the substrate in the substrate mixture supplied to the storage tank . Therefore, in the substrate, while being stored in the storage tank, the reaction of dissociating lignin from the substrate with ammonia or swelling the substrate proceeds without heating.

  Therefore, in the saccharification pretreatment method of the present invention, the saccharification pretreatment product in which the substrate mixture is stored in the storage tank for a predetermined time to dissociate lignin from the substrate without heating or the substrate is swollen. Can be obtained, and the cost required for the pre-saccharification treatment can be reduced.

In the saccharification pretreatment method of the present invention, next, the saccharification pretreatment product is continuously taken out from the storage tank, and heated while being conveyed by ammonia separation means disposed immediately below the storage tank to vaporize ammonia. by dissipating by, separating the ammonia from the pretreated product for saccharification. Thereby , the pre-saccharification product from which ammonia has been separated can be obtained.
In the saccharification pretreatment method of the present invention, the saccharification pretreatment product from which the ammonia has been separated is then discharged from the ammonia separation means and transferred to a subsequent process.

  In the saccharification pretreatment method of the present invention, ammonia water having a concentration in the range of 20 to 30% by mass is preferably supplied to the substrate at a mass ratio in the range of 1: 0.7 to 1: 1.3. . By doing so, it is possible to more uniformly impregnate the substrate with the ammonia water, and to easily dissociate lignin from the substrate or swell the substrate.

  Here, when the concentration of the ammonia water is less than 20% by mass, dissociation of lignin from the substrate or swelling of the substrate may be insufficient. On the other hand, even when the concentration of the ammonia water exceeds 30% by mass, no further effect can be obtained with respect to dissociation of lignin from the substrate or swelling of the substrate.

  Further, when the ammonia water added to 1 part by mass of the substrate is less than 0.7 parts by mass, the ammonia water becomes too small to uniformly impregnate the substrate with the ammonia water. Sometimes. As a result, dissociation of lignin from the substrate or swelling of the substrate may be insufficient.

  On the other hand, even if the ammonia water added to 1 part by mass of the substrate exceeds 1.3 parts by mass, no further effect can be obtained with respect to dissociation of lignin from the substrate or swelling of the substrate. .

The block diagram which shows the example of 1 structure of the apparatus for enforcing the saccharification pre-processing method of lignocellulosic biomass of this invention. Explanatory sectional drawing which shows an example of the mixing means used for the saccharification pre-processing apparatus of lignocellulosic biomass shown in FIG.

  Next, embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

  In the lignocellulosic biomass saccharification pretreatment method of the present embodiment, lignocellulosic biomass saccharification pretreatment is performed using the lignocellulosic biomass saccharification pretreatment device 1 shown in FIG. The lignocellulosic biomass saccharification pretreatment device 1 includes a treatment means 2, an ammonia separation means 3, and a transfer means 4.

  The treatment means 2 mixes lignocellulosic biomass as a substrate and water to form a substrate mixed solution, and dissociates lignin from the substrate in the substrate mixed solution or swells the substrate before saccharification. A device for obtaining a processed product, and the ammonia separation means 3 is a device for separating ammonia from the pre-saccharification product. The transfer means 4 is a device for transferring the pre-saccharification product from which ammonia has been separated to a subsequent enzyme saccharification step.

  In this embodiment, for example, rice straw can be used as the lignocellulosic biomass as the substrate.

  The processing unit 2 includes a processing tank 21, and the processing tank 21 includes a substrate supply unit 22 that continuously supplies the substrate and an ammonia water supply unit 23 that continuously supplies ammonia water. Further, the treatment tank 21 is provided with a mixing means (not shown) for stirring the substrate and the aqueous ammonia to impart shearing force and impact force to the substrate and mixing the aqueous ammonia and the substrate. . Furthermore, the treatment tank 21 is provided with a discharge means 24 for continuously discharging a substrate mixture obtained by mixing ammonia water and the substrate.

  Further, the processing means 2 includes a silo 25 as a storage means for storing the substrate mixture discharged from the processing tank 21 by the discharge means 24. The silo 25 is disposed directly below the processing tank 21. The lower end of the discharge means 24 is inserted into a silo 25, and the silo 25 is connected to the processing tank 21 via the discharge means 24.

  The silo 25 obtains a saccharification pretreatment product by dissociating lignin from the substrate without heating or swelling the substrate while storing the substrate mixture for a predetermined time. The silo 25 is provided with an exhaust port 26 at the top thereof. The exhaust port 26 has a function of discharging ammonia gas and air mixed when the substrate mixture is discharged from the processing tank 21 by the discharge unit 24 to the outside.

  The ammonia separation means 3 includes a powder feeder 3a that supplies the pre-saccharification product obtained in the silo 25 to the inside. The powder feeder 3 a is disposed directly below the silo 25 and is directly connected to the silo 25.

  Next, the saccharification pretreatment method of the present embodiment using the saccharification pretreatment apparatus 1 will be described.

  In the saccharification pretreatment method of the present embodiment, first, in the treatment means 2, the substrate is continuously supplied from the substrate supply means 22 to the treatment tank 21, and ammonia water is continuously supplied from the ammonia water supply means 23 to the treatment tank 21. To supply. For example, rice straw can be used as the substrate. The rice straw is pulverized to a length of about 3 mm by a cutter mill (not shown), for example.

  Moreover, as this ammonia water, what is provided with the density | concentration of the range of 20-30 mass%, for example, the density | concentration of 25 mass% is used in this embodiment. When supplying the ammonia water, the ammonia water supply means 23 is in the range of 0.7 to 1.3 parts by mass of the ammonia water with respect to 1 part by mass of the substrate supplied by the substrate supply means 22. Preferably, 1 part by mass is supplied.

  The substrate and the ammonia water supplied as described above are stirred in the treatment tank 21, whereby the ammonia water and the substrate are mixed to form a substrate mixture. At this time, the substrate is given an impact force due to a collision with the ammonia water supplied simultaneously, a collision between the substrates, a collision between the substrate and the treatment tank 21, and a shearing force due to the stirring. The As a result, the ammonia water is uniformly impregnated in the substrate.

  Next, the substrate mixture is continuously discharged from the treatment tank 21 by the discharge means 24 and supplied to the silo 25. At this time, although the substrate mixture is a wet powder, the silo 25 is disposed immediately below the treatment tank 21, and the lower end of the discharge means 24 is inserted into the silo 25. Accordingly, the substrate mixture is supplied to the silo 25 without causing the bridging phenomenon to block the discharge means 24.

  At this time, ammonia gas and air are mixed in the silo 25 together with the substrate mixture. However, since the ammonia gas and air are discharged to the outside of the silo 25 from the exhaust port 26 provided in the upper part of the silo 25, the ammonia gas and air hinder the storage of the substrate mixture in the silo 25. There is no.

  In the present embodiment, for example, a mixer 31 (manufactured by Taihei Koki Co., Ltd., trade name: spiral pin mixer (W type)) having the configuration shown in FIG. The mixer 31 includes a housing 34 including a flat upper lid 32 and an inverted conical side wall 33 continuous downward from the outer peripheral edge of the upper lid 32, and a powder inlet 35 and a liquid inlet 36 at the center of the upper lid 32. And concentrically. The housing 34 includes a rotatable mixing rotor 37 inside and a discharge port 38 that opens to a part below the side wall 33.

  The mixing rotor 37 includes a horizontal surface 39 that faces the upper lid 32 with a space therebetween, and a slope 40 that extends downward from the outer peripheral edge of the horizontal surface 39 and faces the side wall 33 with a space therebetween. . A plurality of primary dispersion pins 41 are spirally disposed on the horizontal surface 39, and a plurality of secondary dispersion pins 42 are disposed on the inclined surface 40.

  In the mixer 31, the powder inlet 35 corresponds to the substrate supply unit 22, and the liquid inlet 36 corresponds to the ammonia water supply unit 23. Further, the discharge port 38 corresponds to the discharge unit 24, and the mixing rotor 37 corresponds to the mixing unit.

  According to the mixer 31, while rotating the mixing rotor 37, the substrate is continuously supplied from the powder inlet 35 and the ammonia water is continuously supplied from the liquid inlet 36. In this way, the ammonia water is diffused in the outer circumferential direction along the horizontal surface 39 of the mixing rotor 37, while the substrate is agitated by joining the ammonia water on the horizontal surface 39. The substrate is given an impact force and a shearing force by colliding with the primary dispersion pin 41 while being stirred as described above.

  Next, the substrate flows down along the slope 40 of the mixing rotor 37 together with the ammonia water, and is pushed upward by the secondary dispersion pins 42. As a result, the ammonia water and the substrate are mixed, and the substrate mixture in which the ammonia water is uniformly impregnated is formed and continuously discharged from the discharge port 38.

  The treatment tank 21 can stir the supplied substrate and the ammonia water to apply shear force and impact force to the substrate, and mix the ammonia water and the substrate to form the substrate mixture. Anything that can be used is acceptable, and the present invention is not limited to the mixer 31 shown in FIG. As such a treatment tank 21, in addition to the mixer 31 shown in FIG. 2, a continuous jet mixer (for example, manufactured by Powder Research Powtex Co., Ltd., trade name: Flow Jet Mixer), a grindstone grinder (for example, Masuko Industry Co., Ltd. Manufactured, trade name: Super Grinder).

  Next, in the saccharification pretreatment method of the present embodiment, the substrate mixture continuously discharged from the processing tank 21 by the discharge means 24 and supplied to the silo 25 is stored in the silo 25. The substrate mixture passes through the silo 25 for a period in the range of 24-360 hours, for example 100 hours, without being heated, for example at a temperature of 25 ° C.

  At this time, the substrate has a concentration in the range of 20 to 30% by mass, for example, 25% by mass of ammonia water in a range of 0.7 to 1.3 parts by mass with respect to 1 part by mass of the substrate. For example, 1 part by mass is uniformly impregnated. Therefore, the substrate is subjected to the action of ammonia while passing through the silo 25, and lignin is dissociated from the substrate or the substrate is swollen. As a result, lignin is dissociated from the substrate, or a pre-saccharification product in which the substrate is swollen is formed.

  The saccharification pretreatment product is continuously taken out from the silo 25 by the powder feeder 3 a and supplied to the ammonia separation means 3. Since the pre-saccharification product is difficult to be discharged, the powder feeder 3a is directly connected directly below the silo 25, and has a function of forcibly cutting out the pre-saccharification product by a scraper and supplying it to the ammonia separation means 3. preferable. Examples of such a powder feeder 3a include a continuous quantitative feeder (for example, trade name: Smooth Auto Feeder CF300, manufactured by Daimori Industrial Co., Ltd.).

  The ammonia separation means 3 dissipates as ammonia gas by heating the saccharification pretreatment product to vaporize ammonia. The ammonia separation means 3 may be any one as long as it can heat the pre-saccharification product and dissipate ammonia gas. For example, a continuous conduction heat transfer dryer ( For example, Okawara Manufacturing Co., Ltd., a brand name: Inner tube rotary) etc. can be used.

  The pre-saccharification product from which ammonia has been separated by the ammonia separation means 3 is transferred to a subsequent enzymatic saccharification step by the transfer means 4.

  DESCRIPTION OF SYMBOLS 1 ... Saccharification pretreatment apparatus of lignocellulosic biomass, 2 ... Processing means, 3 ... Ammonia separation means, 21 ... Treatment tank, 22 ... Substrate supply means, 23 ... Ammonia water supply means, 24 ... Discharge means.

Claims (3)

Treating a substrate mixture formed by mixing lignocellulosic biomass and ammonia water as a substrate to dissociate lignin contained in the substrate, or swelling the substrate to obtain a pre-saccharification product;
In the pretreatment method for saccharification of lignocellulosic biomass in which the step of separating ammonia from the pre-saccharification product is continuously performed,
Continuously supplying the substrate and the ammonia water to a treatment tank;
The substrate supplied to the treatment tank and the ammonia water are agitated to impart shearing force and impact force to the substrate, and the ammonia water and the substrate are mixed to form a wet powder. Obtaining a mixture;
The substrate mixture is continuously discharged from the treatment tank into a storage tank disposed immediately below the treatment tank, and ammonia gas and air are discharged from the storage tank;
Storing the substrate mixture discharged from the treatment tank in the storage tank for a predetermined time, dissociating lignin contained in the substrate in an unheated state during storage, or swelling the substrate;
The saccharification pretreated product in which the lignin is dissociated or the substrate is swollen is continuously taken out from the storage tank and heated while being transported by an ammonia separation means arranged immediately below the storage tank to vaporize ammonia. Separating ammonia from the pre-saccharification product by dissipating the product,
A pre-saccharification pretreatment method for lignocellulosic biomass, comprising a step of discharging the pre-saccharification product from which ammonia has been separated from the ammonia separation means and transferring it to a subsequent step.   In the pre-saccharification pretreatment method for lignocellulosic biomass according to claim 1,
  The treatment tank is provided with a flat plate-shaped upper lid, a housing composed of an inverted conical side wall extending downward from the outer periphery of the upper lid, and a concentric circle at the center of the upper lid, and the substrate and the ammonia water are continuously provided. A powder charging port and a liquid charging port that are supplied into the housing, a mixing rotor that is rotatably provided inside the housing and that stirs the substrate and the ammonia water, and opens to a part below the side wall. A discharge port for continuously discharging the substrate mixture,
  The mixing rotor includes a horizontal plane facing the upper lid with a gap therebetween, and a slope facing the lower side from an outer peripheral edge of the horizontal plane and facing the side wall with a gap, A plurality of primary dispersion pins arranged spirally on a horizontal plane, and a plurality of secondary dispersion pins arranged on the slope,
  Applying impact and shear forces to the impinging substrate by the primary dispersion pins;
  The substrate mixture in which the ammonia water and the substrate are mixed and the substrate is impregnated with the ammonia water by pushing up the substrate flowing down along the slope with the ammonia water by the secondary dispersion pins. A saccharification pretreatment method for lignocellulosic biomass, characterized by comprising: In the pre-saccharification pretreatment method for lignocellulosic biomass according to claim 1 or 2,
Pretreatment for saccharification of lignocellulosic biomass, wherein ammonia water having a concentration in the range of 20 to 30% by mass is supplied to the substrate at a mass ratio in the range of 1: 0.7 to 1: 1.3. Method.

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