JP5103260B2 - Method and apparatus for saccharification and decomposition of cellulosic biomass - Google Patents

Description

  The present invention relates to a decomposition method and apparatus for efficiently producing saccharides using biomass, particularly cellulosic biomass, as a raw material.

  As part of biomass energy utilization, there is an attempt to obtain cellulose (bioethanol) by decomposing cellulose or hemicellulose which is a main component of a plant. There, it is planned that the obtained ethanol is partially mixed into automobile fuel mainly for fuel use or used as an alternative fuel for gasoline.

  The main components of the plant are cellulose (polymer of glucose, which is a C6 monosaccharide composed of 6 carbons), hemicellulose (polymer of C5 and C6 monosaccharides composed of 5 carbons), lignin, Although it is starch and the like, ethanol is produced by fermentation of yeast or the like using saccharides such as C5 monosaccharides, C6 monosaccharides, and oligosaccharides that are complexes thereof as raw materials.

  Cellulosic biomass such as cellulose and hemicellulose is decomposed into saccharides by 1) hydrolysis using strong acid oxidizing power such as sulfuric acid, 2) enzymatic decomposition, 3) oxidation of supercritical water or subcritical water, etc. Three types of methods using power are going to be used industrially. However, in the acid decomposition method of 1), since the added acid becomes an inhibitor for fermentation of yeast or the like, after the cellulose or hemicellulose is decomposed into saccharides, the acid added before ethanol fermentation of the saccharides Neutralization treatment is essential, and there are aspects that are difficult to put to practical use economically due to the treatment cost.

  In addition, although the enzymatic decomposition method of 2) can be processed at room temperature and constant pressure, an effective enzyme has not been found, and even if it is found, the production cost of the enzyme is expected to increase. There is still no prospect of realization on an industrial scale.

  Here, as a method of hydrolyzing cellulose or the like with supercritical water or subcritical water in 3) to obtain saccharides, the cellulose powder is hydrolyzed by contacting it with hot hot water at 240 to 340 ° C. A method for producing a water-insoluble polysaccharide is disclosed in Patent Document 1. In addition, hydrothermally pressurized the stripped biomass with hot water pressurized at 140-230 ° C to a saturated steam pressure or higher for a predetermined time to decompose and extract hemicellulose, and then heated to a temperature higher than the decomposition temperature of semicellulose. Patent Document 2 discloses a method of decomposing and extracting cellulose by hydrolyzing with a liquid. In addition, cellulose having an average degree of polymerization of 100 or more is contact-reacted with supercritical water or subcritical water having a temperature of 250 to 450 ° C. and a pressure of 15 to 450 MPa, followed by cooling to 0.01 to 5 seconds, and then cooled to a temperature of 250 ° C. Patent Document 3 discloses a method for producing glucose and / or water-soluble cellooligosaccharide, which is hydrolyzed by contact with subcritical water at 350 ° C. or lower and a pressure of 15 MPa or higher and 450 MPa or lower for 1 second or longer and 10 minutes or shorter. Has been.

On the other hand, a biomass system in which an object to be processed containing a solvent mainly composed of low molecular weight alcohol and biomass waste is contained in a sealed container, and the inside of the sealed container is pressurized and heated to a supercritical state of low molecular weight alcohol. A waste disposal method is disclosed in Patent Document 4. Also, a method for decomposing and liquefying biomass in which cellulosic biomass or the like is treated under a supercritical condition or subcritical condition of alcohol using a mixed solvent obtained by adding 5 to 20% by volume of water to C1 to C8 aliphatic alcohol. Is disclosed in Patent Document 5.
JP 2000-186102 A JP 2002-59118 A Japanese Patent Laid-Open No. 2003-212888 JP 2001-170601 A JP-A-2005-296906

  The method of saccharifying and decomposing cellulose and hemicellulose, which are the main components of biomass, with high-temperature and high-pressure supercritical water or subcritical water does not require acid neutralization compared to hydrolysis using a strong acid, so the processing cost is also high. It is a cheap and environmentally friendly treatment method. However, when supercritical water or subcritical water is used, decomposition of cellulose and hemicellulose is completed within seconds to minutes due to its strong oxidizing power. However, there is a drawback that it is excessively decomposed into an organic acid or the like.

  In laboratory-scale small-scale decomposition equipment, supercritical water or subcritical water in a heating vessel may be rapidly cooled to prevent over-decomposition, but in industrial-scale decomposition equipment, in a short time, It is very difficult to quench a large amount of supercritical water or subcritical water. For this reason, the method for decomposing cellulosic biomass using high-temperature and high-pressure supercritical water or subcritical water has a low saccharide yield on the plant scale, which is one of the factors hindering practical use.

  In addition, in order to use a large amount of supercritical water or subcritical water, a large amount of energy is required for heating the slurry, which increases the processing cost. In the cellulosic biomass decomposition method in which a slurry using alcohol or the like as a solvent is in a supercritical or subcritical state, the vapor pressure becomes very high, and thus more energy is required, and the pressure strength required for the apparatus to be used is also high. Increase.

  A method and apparatus for decomposing cellulose and / or hemicellulose in cellulosic biomass into monosaccharides and oligosaccharides (hereinafter referred to as saccharides) by subcritical high-temperature high-pressure water. The inventors have already filed Japanese Patent Application No. 2006-291194 and Japanese Patent Application No. 2008-512441 for a method and apparatus with excellent rates.

  In the saccharification / decomposition method and saccharification / decomposition apparatus for cellulosic biomass described in the above patent application, a plurality of the same type of pressure vessels are used, and a series of steps are performed in the same pressure vessel. For this reason, the pressure strength of the pressure vessel has to be based on the decomposition process at the highest temperature and pressure, which tends to increase the cost.

  In addition, in the filling step of filling the cellulosic biomass slurry into the pressure vessel, the temperature inside the pressure vessel is about 25 ° C to 120 ° C, whereas in the decomposition step of hydrolyzing the cellulosic biomass into sugars, The temperature is 210 ° C to 280 ° C. For this reason, it repeats with a big temperature history for every series of processes (20 to 40 minutes), and it is necessary to design a strong member in consideration of fatigue strength, which tends to increase the manufacturing cost.

  An object of the present invention is to provide a saccharification / decomposition method and a saccharification / decomposition device which are further improved from the saccharification / decomposition method and saccharification / decomposition device for cellulosic biomass described in the above patent application.

  The present inventor, when decomposing cellulose or hemicellulose into saccharides using subcritical high-temperature high-pressure water, the slurry in the pressure vessel in the high-temperature high-pressure state is a pressure vessel in the middle of heating filled with a slurry of cellulosic biomass. It has been found that if it is flash-evaporated, a large amount of slurry can be rapidly cooled to below the cellulose decomposition temperature, sugar can be prevented from being excessively decomposed into organic acids, etc., and energy can be saved by recovering thermal energy. It was. Furthermore, if only the step of decomposing cellulose or hemicellulose into saccharides using subcritical high-temperature high-pressure water is performed in a dedicated pressure vessel, the pressure at which the inside does not become high-temperature high-pressure such as subcritical state The present invention has been completed by paying attention to the fact that the required standard of pressure strength of the container is lowered, the manufacturing cost of the pressure container is suppressed, and the temperature history can be reduced.

Specifically, the present invention
A method for saccharifying and decomposing cellulosic biomass using a plurality of first low pressure vessels, high pressure vessels and second low pressure vessels,
The filling step, the temperature raising step, the first transfer step, the decomposition step, the second transfer step, the temperature lowering step and the discharge step are sequentially executed,
The filling step is a step of filling the first low pressure container with a slurry obtained by pulverizing cellulosic biomass and mixing with water.
The temperature raising step is a step of raising the temperature by sealing the first low pressure vessel,
The first transfer step is a step of transferring the slurry after the temperature raising step from the first low pressure vessel to the high pressure vessel through the first connection path,
The decomposition step is a step of decomposing cellulose and / or hemicellulose in cellulosic biomass into saccharides in a high-pressure vessel by oxidizing power of high-temperature high-pressure water,
The second transfer step is a step of transferring the slurry after the decomposition step from the high pressure vessel to the second low pressure vessel through the first connection path,
The temperature lowering step is a step of lowering the temperature by flash evaporation of the high temperature and high pressure slurry in the second low pressure vessel.
The discharging step is a step of taking out the slurry in the second low pressure container,
When a filling process is being executed in a certain first low pressure container, a discharging process is being executed in a certain second low pressure container, and the slurry filled in the first low pressure container during the filling process and the discharging process are executed. Heat exchange with the slurry discharged from the second low pressure vessel inside,
When the temperature raising process is being performed in the other first low pressure vessel, the temperature lowering process is being performed in the other second low pressure vessel, and the flash steam discharged from the second low pressure vessel during the temperature lowering process is being executed. The present invention relates to a saccharification / decomposition method for cellulosic biomass, characterized in that heat recovery is performed by supplying to the first low-pressure vessel during the temperature raising process.

The present invention also provides:
A saccharification / decomposition device for cellulosic biomass comprising a plurality of first low pressure vessels, high pressure vessels and second low pressure vessels,
The first low pressure vessel and the high pressure vessel are connected by a first connection path,
The high pressure vessel and the second low pressure vessel are connected by a second connection path,
The second low pressure vessel and the first low pressure vessel are connected by a flush path,
In the first low-pressure vessel, a filling step of pulverizing cellulosic biomass and filling with a slurry mixed with water, and a heating step of sealing and heating the first low-pressure vessel are performed,
The slurry after the temperature raising step is transferred from the first low pressure vessel to the high pressure vessel by the first connection path as the first transfer step,
In the high-pressure vessel, a decomposition process is performed in which cellulose and / or hemicellulose in cellulosic biomass is decomposed into sugars by the oxidizing power of high-temperature high-pressure water,
The slurry after the decomposition step is transferred from the high pressure vessel to the second low pressure vessel by the second transfer path as the second transfer step,
In the second low pressure vessel, a temperature lowering step for lowering the temperature by flash evaporation of the high temperature and high pressure slurry and a discharge step for taking out the slurry in the second pressure vessel are performed,
When a filling process is being executed in a certain first low pressure container, a discharging process is being executed in a certain second low pressure container, and the slurry filled in the first low pressure container during the filling process and the discharging process are executed. Heat exchange with the slurry discharged from the second low pressure vessel inside,
When the temperature raising process is being performed in the other first low pressure vessel, the temperature lowering process is being performed in the other second low pressure vessel, and the flash steam discharged from the second low pressure vessel during the temperature lowering process is being executed. The present invention relates to a saccharification / decomposition apparatus for cellulosic biomass, characterized in that heat recovery is performed by supplying the gas to a first low-pressure vessel during the temperature raising process by a flash path.

  In the saccharification / decomposition method and saccharification / decomposition apparatus for cellulosic biomass of the present invention, a filling step, a temperature increasing step, a decomposing step, a temperature decreasing step, and a discharge in a plurality of first low pressure vessels, high pressure vessels, and second low pressure vessels. The five steps are sequentially performed. Moreover, a 1st transfer process is performed between a temperature rising process and a decomposition process, and a 2nd transfer process is performed between a decomposition process and a high temperature process.

  Here, the high-pressure vessel means a pressure vessel that performs a decomposition step in which the inside becomes a high temperature and high pressure in a subcritical state, and the low-pressure vessel means a pressure vessel that does not perform a decomposition step inside. The low pressure vessel is divided into a first low pressure vessel that performs a filling step and a temperature raising step, and a second low pressure vessel that performs a temperature lowering step and a discharge step. The first low pressure vessel and the high pressure vessel are connected by a first connection path that performs the first transfer step, and the high pressure vessel and the second low pressure vessel are the second connection route that performs the second transfer step. Connected with. Therefore, in the saccharification / decomposition method and saccharification / decomposition apparatus for cellulosic biomass of the present invention, the seven steps of the filling step, the temperature raising step, the first transfer step, the decomposition step, the second transfer step, the temperature lowering step and the discharge step are sequentially executed. Is done.

  Here, “low pressure” means “low pressure than the subcritical state” and does not mean a low pressure near atmospheric pressure. The first low pressure vessel and the second low pressure vessel may be the same type of pressure vessel or different types of pressure vessels.

  By connecting the second low pressure vessel in the temperature lowering step and the first low pressure vessel in the temperature raising step by a flush path, the slurry in the second low pressure vessel in the temperature lowering step can be rapidly cooled by flash evaporation. Therefore, the excessive decomposition of the produced saccharide can be suppressed. At the same time, the slurry in the first low-pressure vessel that performs the temperature raising step can be heated by the high-temperature flash steam, so that it is possible to save energy required for heating the slurry.

  Further, by reducing the pressure from the gas phase portion of the high-pressure vessel, the dissolved components or solids in the slurry do not move, and there is no risk of clogging of nozzles and piping for conducting flash vapor. Further, no special temperature control device or the like is required. Note that the supply of the flash vapor to the preheated side (the first low-pressure vessel in the temperature raising step) is more effective if it is supplied into the slurry liquid.

  Moreover, in the saccharification / decomposition method and saccharification / decomposition apparatus for cellulosic biomass of the present invention, the slurry discharged from the second pressure vessel in the discharging step and the slurry charged in the first low pressure vessel in the filling step Therefore, it is possible to further save energy required for heating the slurry.

  The pressure resistance of the pressure vessels (the first low pressure vessel and the second low pressure vessel) that perform the other steps by performing the decomposition step of hydrolyzing the cellulosic biomass slurry in the subcritical state only in the high pressure vessel Since the required standard of strength can be reduced, the manufacturing cost of the entire pressure vessel can be suppressed. Moreover, the temperature change (temperature history) of each pressure vessel is also reduced. Furthermore, as a result of a decrease in the required standard of pressure strength, the structure of the pressure vessel is simplified and the maintainability is improved.

  When all the seven steps have the same required time, it is preferable that the base numbers of the first low pressure vessel, the high pressure vessel and the second low pressure vessel are 3 m (m is a natural number). This is to smoothly perform a series of processing steps while performing two heat recoveries.

  When all six steps other than the decomposition step have the same required time and the required time for the decomposition step is n times the required time for the other six steps (n is a natural number), the first low pressure The number of radixes of the container and the second low pressure vessel is preferably 3 m (m is a natural number), and the number of radixes of the high pressure vessel is preferably m (n + 2). If the decomposition step is n times longer than the other steps, the base number of the high-pressure vessel that performs the decomposition step is m (n + 2), and the base number of the first low-pressure vessel or the second low-pressure vessel that performs the other step is 3 m. A series of processing steps can be performed smoothly while performing two heat recoveries. Note that m = n.

  If the temperature in the decomposition step is 140 ° C. or higher and 200 ° C. or lower, hemicellulose can be decomposed into saccharides (mainly C5 monosaccharide). In the case of biomass having a high hemicellulose content, when treated at a high temperature, C5 monosaccharides and the like are excessively decomposed into organic acids and the like, and therefore, it is preferable to perform the decomposition treatment under relatively mild conditions. Note that the temperature in the decomposition step when decomposing hemicellulose is more preferably 160 ° C. or higher and 200 ° C. or lower.

Thereafter, the slurry generated in the discharge step is subjected to solid-liquid separation, and the solid content after the hemicellulose is decomposed and eluted to the solvent side is separated to form a new raw material slurry, which is again supplied to the filling step, and the decomposition step If the temperature is 240 ° C. or higher and 280 ° C. or lower, cellulose can be decomposed into saccharides (mainly C6 monosaccharide).

  First, hemicellulose in biomass is decomposed into sugars in a temperature range of 140 ° C. or more and 180 ° C. or less, and then solid-liquid separation can separate the cellulose as a solid. If this cellulose is used as a slurry in the filling step and the decomposition step is performed in a temperature range of 240 ° C. or higher and 280 ° C. or lower, the cellulose can be decomposed into sugars. It is effective for biomass having the same cellulose and hemicellulose content.

  If the temperature in the decomposition step is 240 ° C. or higher and 280 ° C. or lower, cellulose can be decomposed into saccharides (mainly C6 monosaccharide). In the case of biomass with a high cellulose content, it is less necessary to consider hemicellulose overdegradation, so it is more effective to decompose only cellulose into saccharides at a relatively high temperature.

  As described above, according to the present invention, it is possible to hydrolyze hemicellulose and cellulose contained in biomass by selecting either one or both of them by controlling the temperature of the decomposition step using the same decomposition apparatus. . However, it is usually more economical to use separate decomposing apparatuses in accordance with the pressure resistance specifications for hemicellulose decomposition and cellulose decomposition.

  In the filling step, it is preferable to add 2 mol% or more and 10 mol% or less of ethanol to the raw slurry. By adding a small amount of ethanol to the raw material slurry, the decomposition reaction rate of cellulose and / or hemicellulose into saccharides by subcritical water becomes slow. Thereby, the yield can be increased by adjusting the decomposition time of cellulose and / or hemicellulose in the decomposition step and easily preventing excessive decomposition to an organic acid or the like.

  Here, most of the ethanol added to the raw material slurry is transferred to flash steam in the temperature lowering process, and is recovered into a slurry in another pressure vessel in the temperature increasing process. The aqueous solution containing the saccharide taken out in the discharging step is subjected to ethanol fermentation and converted into bioethanol. However, if ethanol remains at the beginning of ethanol fermentation, fermentation by yeast is inhibited. The invention according to claim 7 is characterized in that ethanol fermentation is unlikely to be inhibited because the slurry containing cellulose and / or hemicellulose after the discharging step maintains ethanol concentration in the decomposition step and ethanol decreases.

  As disclosed in Patent Document 4 or Patent Document 5, when a medium mainly composed of alcohol or the like is in a subcritical state, the pressure vessel has a high pressure of 12 MPa or more at 280 ° C., for example. However, in the invention according to claim 7, the pressure is only about 7.5 to 9.7 MPa at the same 280 ° C., and the pressure energy can be saved, and the required pressure strength of the pressure vessel can be further reduced, which is economical.

  According to the present invention, cellulose and / or hemicellulose in cellulosic biomass can be decomposed into saccharides at low cost and with high yield using a plurality of pressure vessels. In addition, according to the present invention, the waste heat of the pressure vessel in another process can be easily recovered to preheat to a temperature suitable for the saccharification / decomposition reaction, so that it is possible to save about 60% of the required heat amount and economically. Very good.

  Further, the cost of the pressure vessel can be reduced and the maintainability is improved as compared with the saccharification / decomposition method and the saccharification / decomposition apparatus for cellulosic biomass described in Japanese Patent Application Nos. 2006-291194 and 2008-512461.

  Embodiments of the present invention will be described below with reference to the drawings as appropriate. The present invention is not limited to the following.

(Embodiment 1)
As Embodiment 1 of the present invention, a saccharification / decomposition apparatus that uses three first low-pressure pressure vessels, three high-pressure pressure vessels, and second low-pressure pressure vessels, each of which requires a total of seven time steps, will be described.

  FIG. 1 is a schematic configuration diagram of a saccharification / decomposition apparatus according to the present embodiment. This saccharification / decomposition apparatus includes first low-pressure pressure vessels 5a to 5c, first connection paths (paths 6a, 6b and 6c → path 7 → paths 8a, 8b and 8c → paths 9a, 9b and 9c), and high-pressure pressure containers 10a to 10c. 10c, second connection path (paths 11a, 11b, 11c → paths 12a, 12b, 12c → path 13 → paths 14a, 14b, 14c), second low pressure vessels 15a-15c, flush path (paths 16a, 16b, 16c) → path 17 → paths 18a, 18b, 18c), and accessory devices.

Cellulosic biomass (eg, plant biomass such as bagasse, sugar beet lees, straw, etc.) is pulverized to a size of several mm or less (preferably 100 μm or less), and solid using water or dilute ethanol aqueous solution (2 to 10 mol%) A raw material slurry having an object concentration of 30% or less (preferably about 20%) is used. The raw material slurry 2 in the raw material tank 1 is filled by the pump P ₁ into the first low pressure vessels 5a to 5c via the heat exchanger 3 and the filling paths 4a to 4c (filling step).

  After filling the raw material slurry, the first low pressure containers 5a to 5c are sealed. When the saccharification / decomposition apparatus is started, the slurry is not preheated by heat exchange because there is no thermal energy discharged from the second low pressure vessels 15a-15c. After the start of operation, the temperature is raised by the flash vapor supplied from the second low pressure vessels 15a to 15c (temperature raising step).

After the temperature raising step, the slurry heated to 70 ° C. to 120 ° C. is supplied to the high temperature pressure vessels 10a to 10c through the first connection path by the pumps P _{2 to} P ₄ (first transfer step).

Heat exchangers 21a to 21c are installed in the paths 9a to 9c, respectively, and the slurry is heated by the thermal energy supplied from an external heat source (for example, high temperature steam or the like) until it becomes a subcritical state. At this time, until the slurry is in a subcritical state, the high-pressure pressure vessels 10a, 10b, 10c → paths 11a, 11b, 11c → paths 9a, 9b, 9c → high-pressure pressure containers 10a, 10b by the pumps P _{5 to} P ₇ . , 10c. And if it becomes predetermined temperature, the cellulosic biomass contained in a slurry will be decomposed | disassembled into saccharides in a high pressure container by the oxidizing power of high temperature high pressure water (decomposition | disassembly process).

  At this time, if ethanol is added to the raw material slurry in a concentration range of 2 mol% or more and 10 mol% or less, the decomposition reaction rate can be reduced, so that the decomposition reaction of cellulose or hemicellulose can be easily controlled.

  Here, the decomposition step referred to in the present invention includes not only the time during which the slurry is in the subcritical state but also the time for heating the slurry whose temperature has been raised in the temperature raising step to the subcritical state. .

  When ethanol is added to a concentration exceeding 10 mol% with respect to the raw slurry, the decomposition time is prolonged more than necessary and the pressure resistance required for the pressure vessel is increased. Moreover, since ethanol remains at a high concentration in the discharge (drainage) slurry in the discharge process, the practical value is impaired.

  Here, when saccharifying and decomposing hemicellulose in biomass in the decomposition step, the temperature is not raised to a temperature range (240 ° C to 280 ° C) where the cellulose is saccharified and decomposed, but only hemicellulose is saccharified and decomposed to 140 ° C to 180 ° C. Adjust to the temperature range. On the other hand, when saccharifying and decomposing cellulose in biomass, the temperature is raised to a temperature range (240 ° C. to 280 ° C.) at which cellulose saccharifies and decomposes.

The high-temperature and high-pressure slurry after the decomposition step is supplied to the second low-pressure vessels 15a to 15c through the second connection path (second transfer step). At this time, since the high pressure vessels 10a to 10c and the second low pressure vessels 15a to 15c are connected by the second connection path and the internal volume is doubled, the pressure and temperature of the slurry are lower than in the decomposition step. Thereby, the inside of a high-pressure pressure vessel, a 2nd connection path, and a 2nd low-pressure pressure vessel falls to saccharification decomposition temperature or less, and it can stop the hyperdecomposition reaction to the organic acid etc. of saccharides. In the second transfer step, the pumps P _{5 to} P ₇ can be set to a low output state.

  After the second transfer step, the second low pressure containers 15a to 15c and the second connection path are shut off. Then, the flash vapor generated from the slurry in the second low-pressure pressure vessels 15a to 15c is supplied to the first low-pressure pressure vessels 5a to 5c in the temperature raising process through the flush path, and the second low-pressure pressure vessels 15a to 15c Lower the slurry temperature (temperature lowering step).

  At this time, by heating the raw slurry in the first low pressure vessels 5a to 5c, heat recovery of the flash vapor is performed, and energy for making the slurry sub-critical in the decomposition step is saved. Note that the flash vapor is preferably supplied to the raw slurry in the first low pressure vessel.

After cooling step, the slurry in the second low pressure vessel 15a~15c, the path 19a, 19b, via 19c, by the pump _{P 8,} through the path 20 → the heat exchanger 3 → path 22 to the sugar solution tank 23 Stored (discharge process).

  At this time, the slurry flowing through the path 20 is about 110 to 150 ° C. when the temperature in the decomposition process is 240 to 280 ° C., so that the heat exchanger 3 transfers the slurry from the raw material tank 1 to the first low pressure vessels 5 a to 5 c. Heat exchange with the slurry to be filled. Thereby, while the raw material slurry with which 1st low pressure vessel 5a-5c is filled is preheated, the slurry stored to the sugar solution tank 23 via the path | route 23 can be cooled.

  Each of the first low pressure vessel, the high pressure vessel and the second low pressure vessel for each of the three units repeats a filling process → a temperature rising process → a decomposition process → a temperature lowering process → a discharge process in order, and the entire apparatus is a filling process → an ascending process. Seven steps of temperature process → first transfer process → decomposition process → second transfer process → cooling process → discharge process are sequentially repeated. The three first low pressure vessels, the high pressure vessel, and the second low pressure vessel are not operated at the same time but are operated with a time difference.

  That is, in FIG. 1, 5a is a filling process, 5b is a first transfer process, and 5c is a temperature raising process; 10a is a first transfer process, and 10b is a second transfer process. The transfer process, 10c is the decomposition process; the second low-pressure vessel 15a is the second transfer process, 15b is the discharge process, and 15c is the temperature lowering process. In addition, the location shown with the thick line in FIG. 1 represents the state which the slurry or flash vapor | steam is moving.

  When the saccharification / decomposition apparatus is already operated and the second and subsequent filling steps are performed in the first low-pressure pressure vessels 5a to 5c, they are discharged (drained) from the second low-pressure pressure vessels 15a to 15c in the discharge step. Heat exchange is performed between the slurry (including saccharides) and the raw slurry filled in the first low pressure containers 5a to 5c to preheat the raw slurry.

  Sugar and residual solids coexist in the slurry discharged (drained) in the discharging step and further cooled by heat exchange. When the decomposition step is in the temperature range of 140 ° C. to 180 ° C., the residual solid content is mainly cellulose and lignin, and when the decomposition step is in the temperature range of 240 ° C. to 280 ° C., the residual solid content is Mainly lignin.

  The slurry is subjected to ethanol fermentation after removing the remaining solid content by solid-liquid separation, and bioethanol is produced by the fermentation action of yeast and the like. Since such ethanol fermentation technology is a well-known technology, the description thereof is omitted here, but the saccharide obtained by the present invention can be converted into bioethanol by a known fermentation treatment other than yeast fermentation.

  Next, a time schedule when the saccharification / decomposition apparatus shown in FIG. 1 is operated as a continuous batch system will be described with reference to FIG. In FIG. 2, the time required for each step is 5 minutes.

  First, in the first low pressure vessel, the filling process is performed from No. 1, and the filling process is sequentially performed in No. 2 and No. 3 with a time difference of 5 minutes. Each first low-pressure pressure vessel sequentially repeats the three steps “C” → “PH” → “X1”. The raw material slurry in the first low-pressure vessel No. 1 is transferred to the high-pressure vessel No. 1 in the first transfer step “X1”. Similarly, the raw slurry in the first low pressure vessel No. 2 and No. 3 is transferred to the high pressure vessel No. 2 and No. 3, respectively.

  In the first low pressure vessel No.1, the first and second “PH”, and in the first low pressure vessel No.2 and No.3, the first “PH” is the flash steam from the second low pressure vessel. Since there is no supply, the raw slurry may be preheated by thermal energy from an external heat source.

  In the high pressure vessel, the first transfer process “X1” is performed from No.1, and the first transfer process “X1” is sequentially performed in No.2 and No.3 with a time difference of 5 minutes. Each high-pressure vessel repeats the three steps “X1” → “GL” → “X2” sequentially. The high-temperature and high-pressure slurry in the high-pressure vessel No. 1 is transferred to the second low-pressure vessel No. 1 in the second transfer step “X2”. Similarly, the high-temperature and high-pressure slurry in the high-pressure pressure vessels No. 2 and No. 3 is transferred to the second low-pressure pressure vessels No. 2 and No. 3, respectively.

  In the second low pressure vessel, the second transfer process “X2” is performed from No. 1, and the second transfer process “X2” is sequentially performed in No. 2 and No. 3 with a time difference of 5 minutes. Each second low pressure vessel sequentially repeats the three steps “X2” → “F” → “DC”.

  The flash vapor in the second low pressure vessel No. 1 in the temperature lowering step “F” is supplied to the first low pressure vessel No. 2 in the temperature raising step “PH”, and heat recovery can be achieved. Similarly, the second low pressure pressure vessel No. 2 and No. 3 flash steam in the temperature lowering process “F” are respectively transferred to the No. 3 and No. 1 first low pressure pressure vessels in the temperature raising process “PH”. It is supplied and heat recovery is achieved.

  In addition, the slurry discharged (drained) from the second low pressure vessel No. 1 in the discharge step “DC” is the same as the raw slurry and heat filled in the first low pressure vessel No. 1 in the filling step “C”. Exchanged. Similarly, the slurry discharged from the second low pressure vessel No. 2 and No. 3 in the discharge step “DC” is filled in the first low pressure vessel No. 2 and No. 3 in the filling step “C”. Heat exchange with the raw material slurry is performed.

  According to such a continuous batch system, cellulosic biomass can be continuously saccharified and decomposed in a short time and with energy saving. In the present embodiment, the first low-pressure pressure vessel No. 1 starts the filling process “C” and the second low-pressure pressure vessel No. 1 completes the discharge process “DC”. 35 minutes.

[Effect of ethanol addition in the decomposition process]
Here, the influence of ethanol addition in the case of saccharifying and decomposing reagent cellulose in a subcritical state as a cellulosic biomass was examined. FIG. 3 shows the experimental results of passing pure water and 5 wt% (2 mol%) ethanol aqueous solution through the cellulose at 280 ° C.

  FIG. 3 shows the relationship between reaction time and saccharide yield (%). The maximum yield of saccharide itself was hardly affected by the addition of ethanol. However, the production rate and decomposition rate of saccharides are clearly lower when ethanol is added. For example, the time to reach the maximum yield is increased by about 3 times (0.7 minutes → 2.0 minutes) by adding ethanol. .

  Since it is difficult to control the reaction time in the subcritical state in seconds on an industrial scale, it was confirmed that the addition of ethanol to the raw slurry was effective in increasing the yield of saccharides.

(Embodiment 2)
As Embodiment 2 of the present invention, the time required for all 6 processes other than the decomposition process is 2.5 minutes, and the time required for the decomposition process is 5 minutes (twice the time required for 6 processes other than the decomposition process) FIG. 4 shows a time schedule for operating a saccharification / decomposition apparatus in which the number of the first low-pressure pressure vessel and the number of the second low-pressure pressure vessel are 3 and the number of the high-pressure pressure vessel is 4, respectively, as a continuous batch system. While explaining.

  The time required for the 6 steps other than the decomposition step is shortened because the decomposition step is a step of hydrolyzing cellulose and / or hemicellulose in cellulosic biomass into saccharides, and therefore requires at least about 5 minutes. This is because time is required, while the other steps are merely heating, cooling, transferring, or moving the flash vapor of the slurry, so that the required time can be shortened.

  First, in the first low pressure container, the filling process is performed from No. 1, and the filling process is sequentially performed in the first low pressure container No. 2 and No. 3 with a time difference of 2.5 minutes. Each first low pressure vessel sequentially repeats the three steps “C” → “PH” → “X1”. The raw material slurry in the first low-pressure vessel No. 1 is transferred to the high-pressure vessel No. 1 in the first transfer step “X1”. Similarly, the raw slurry in the first low pressure vessel No. 2 and No. 3 is transferred to the high pressure vessel No. 2 and No. 3, respectively.

  In the high-pressure vessel, the first transfer process “X1” is performed from No. 1, and the first transfer process “X1” is sequentially performed from No. 2 to No. 4 with a time difference of 2.5 minutes. Each high-pressure vessel repeats the three steps “X1” → “GL” → “X2” sequentially.

  Here, in the first low-pressure vessel, the three steps “C” → “PH” → “X1” are completed in 2.5 minutes × 3 = 7.5 minutes. On the other hand, in the high-pressure vessel, the three processes “X1” → “GL” → “X2” are completed in 2.5 minutes + 5 minutes + 2.5 minutes = 10 minutes. For this reason, in the second first transfer step “X1” of the first low pressure container No. 1, the slurry is transferred to the high pressure container No. 4. Hereinafter, similarly, the slurry is sequentially transferred from the first low pressure container No. 1 to No. 3 to the high pressure container No. 1 to No. 4.

  The high-temperature and high-pressure slurry in the high-pressure vessel No. 1 is transferred to the second low-pressure vessel No. 1 in the second transfer step “X2”. Similarly, the high-temperature and high-pressure slurry in the high-pressure pressure vessels No. 2 and No. 3 is sequentially transferred to the second low-pressure pressure vessels No. 2 and No. 3.

  Here, in the high-pressure vessel, the three steps “X1” → “GL” → “X2” are completed in 2.5 minutes + 5 minutes + 2.5 minutes = 10 minutes. On the other hand, in the second low-pressure vessel, the three steps “X2” → “F” → “DC” are completed in 2.5 minutes × 3 = 7.5 minutes. Therefore, in the first second transfer step “X2” of the high pressure vessel No. 4, the slurry is transferred as the second second transfer step “X2” of the second low pressure vessel No. 1. Hereinafter, similarly, the slurry is sequentially transferred from the high pressure vessel No. 1 to No. 4 to the second low pressure vessel No. 1 to No. 3.

  In the second low pressure vessel, the second transfer process “X2” is performed from No. 1, and the second transfer process “X2” is sequentially performed in No. 2 and No. 3 with a time difference of 2.5 minutes. Each second low pressure vessel sequentially repeats the three steps “X2” → “F” → “DC”.

  In the present embodiment, the first low-pressure pressure vessel No. 1 starts the filling process “C” and the second low-pressure pressure vessel No. 1 completes the discharge process “DC”. 20 minutes.

(Embodiment 3)
As Embodiment 3 of the present invention, the time required for the 6 processes other than the decomposition process is 1 minute, and the time required for the decomposition process is 5 minutes (5 times the time required for the 6 processes other than the decomposition process). FIG. 5 shows a time schedule for operating a saccharification / decomposition apparatus in which the number of the first low-pressure pressure vessel and the number of the second low-pressure pressure vessel are 3 and the number of the high-pressure pressure vessel is 7, respectively, as a continuous batch system. While explaining.

  Note that the time required for the six steps other than the decomposition step is shortened for the same reason as described in the second embodiment.

  First, in the first low pressure container, the filling process is performed from No. 1, and the filling process is sequentially performed in the first low pressure container No. 2 and No. 3 with a time difference of 1 minute. Each first low pressure vessel sequentially repeats the three steps “C” → “PH” → “X1”. The raw material slurry in the first low-pressure vessel No. 1 is transferred to the high-pressure vessel No. 1 in the first transfer step “X1”. Similarly, the raw slurry in the first low pressure vessel No. 2 and No. 3 is transferred to the high pressure vessel No. 2 and No. 3, respectively.

  In the high pressure vessel, the first transfer process “X1” is performed from No. 1, and the first transfer process “X1” is sequentially performed from No. 2 to No. 7 with a time difference of 1 minute. Each high-pressure vessel repeats the three steps “X1” → “GL” → “X2” sequentially.

  Here, in the first low pressure vessel, the three steps of “C” → “PH” → “X1” make a round in 1 minute × 3 = 3 minutes. On the other hand, in the high-pressure vessel, the three steps “X1” → “GL” → “X2” are completed in 1 minute + 5 minutes + 1 minute = 7 minutes. For this reason, seven high-pressure pressure vessels are used, and in the second first transfer process “X1” of the first low-pressure pressure vessels No. 1 to No. 3, slurry is transferred to the high-pressure pressure vessels No. 4 to No. 6. Be transported. Then, in the third first transfer step “X1” of the first low pressure container No. 1, the slurry is transferred to the high pressure container No. 7. Hereinafter, similarly, the slurry is sequentially transferred from the first low pressure vessel No. 1 to No. 3 to the high pressure vessel No. 1 to No. 7.

  The high-temperature and high-pressure slurry in the high-pressure vessel No. 1 is transferred to the second low-pressure vessel No. 1 in the second transfer step “X2”. Similarly, the high-temperature and high-pressure slurry in the high-pressure pressure vessels No. 2 and No. 3 is transferred to the second low-pressure pressure vessels No. 2 and No. 3, respectively.

  Here, in the high pressure vessel, the three steps “X1” → “GL” → “X2” make a round in 1 minute + 5 minutes + 1 minute = 10 minutes. On the other hand, in the second low pressure vessel, the three steps “X2” → “F” → “DC” are completed in 1 minute × 3 = 3 minutes. For this reason, in the first second transfer process “X2” of the high-pressure pressure vessels No. 4 to No. 6, the second second transfer process “X2” of the second low-pressure vessel No. 1 to No. 3 The slurry is transferred sequentially. In the first second transfer step “X2” of the high pressure vessel No. 7, the slurry is transferred as the third second transfer step “X2” of the second low pressure vessel No. 1. Hereinafter, similarly, the slurry is sequentially transferred from the high-pressure pressure vessels No. 1 to No. 7 to the second low-pressure pressure vessels No. 1 to No. 3.

  In the second low pressure vessel, the second transfer process “X2” is performed from No. 1, and the second transfer process “X2” is performed at No. 2 and No. 3 with a time difference of 1 minute. Each second low pressure vessel sequentially repeats the three steps “X2” → “F” → “DC”.

  In the present embodiment, the first low-pressure pressure vessel No. 1 starts the filling process “C” and the second low-pressure pressure vessel No. 1 completes the discharge process “DC”. 11 minutes.

  The present invention is useful in fields such as biotechnology and energy as a method and apparatus for decomposing cellulosic biomass and producing saccharides. In addition, it can be applied as a heat-efficient method and apparatus as a pretreatment in the saccharification reaction of biomass by enzyme / yeast.

1 is a schematic configuration diagram of a saccharification / decomposition apparatus according to Embodiment 1. FIG. It is a figure showing the time schedule in the case of operating the saccharification decomposition apparatus of Embodiment 1 as a continuous batch system. It is a graph showing the relationship between the reaction time in the saccharification decomposition reaction of biomass, and the yield (%) of saccharides. It is a figure showing the time schedule in the case of operating the saccharification decomposition apparatus of Embodiment 2 as a continuous batch system. It is a figure showing the time schedule in the case of operating the saccharification decomposition apparatus of Embodiment 3 as a continuous batch system.

Explanation of symbols

1: Raw material tank 2: Raw material slurry 3: Heat exchanger 4a, 4b, 4c: Filling path 5a, 5b, 5c: First low pressure vessel 6a, 6b, 6c: Path 7: Path 8a, 8b, 8c: Path 9a , 9b, 9c: Routes 10a, 10b, 10c: High pressure pressure vessels 11a, 11b, 11c: Routes 12a, 12b, 12c: Routes 13: Routes 14a, 14b, 14c: Routes 15a, 15b, 15c: Second low pressure vessel 16a, 16b, 16c: route 17: route 18a, 18b, 18c: route 19a, 19b, 19c: route 20, 22: route 21a, 21b, 21c: heat exchanger 23: sugar liquid tank

Claims (10)

A method for saccharifying and decomposing cellulosic biomass using a plurality of first low pressure vessels, high pressure vessels and second low pressure vessels,
The filling step, the temperature raising step, the first transfer step, the decomposition step, the second transfer step, the temperature lowering step and the discharge step are sequentially executed,
The filling step is a step of filling the first low pressure container with a slurry obtained by pulverizing cellulosic biomass and mixing with water.
The temperature raising step is a step of raising the temperature by sealing the first low pressure vessel,
The first transfer step is a step of transferring the slurry after the temperature raising step from the first low pressure vessel to the high pressure vessel through the first connection path,
The decomposition step is a step of decomposing cellulose and / or hemicellulose in cellulosic biomass into saccharides in a high-pressure vessel by oxidizing power of high-temperature high-pressure water,
The second transfer step is a step of transferring the slurry after the decomposition step from the high pressure vessel to the second low pressure vessel through the first connection path,
The temperature lowering step is a step of lowering the temperature by flash evaporation of the high temperature and high pressure slurry in the second low pressure vessel.
The discharging step is a step of taking out the slurry in the second low pressure container,
When a filling process is being executed in a certain first low pressure container, a discharging process is being executed in a certain second low pressure container, and the slurry filled in the first low pressure container during the filling process and the discharging process are executed. Heat exchange with the slurry discharged from the second low pressure vessel inside,
When the temperature raising process is being performed in the other first low pressure vessel, the temperature lowering process is being performed in the other second low pressure vessel, and the flash steam discharged from the second low pressure vessel during the temperature lowering process is being executed. A method for saccharifying and decomposing cellulosic biomass, characterized in that heat recovery is performed by supplying to a first low-pressure vessel during the temperature raising step.   The saccharification / decomposition of cellulosic biomass according to claim 1, wherein all of the seven steps have the same required time, and the number of bases of the first low pressure vessel, the high pressure vessel and the second low pressure vessel is 3 m (m is a natural number). Method. When all the 6 steps other than the decomposition step have the same required time, and the required time for the decomposition step is n times (n is a natural number) the required time for the other 6 steps,
The base numbers of the first low pressure vessel and the second low pressure vessel are each 3 m (m is a natural number),
The saccharification / decomposition method for cellulosic biomass according to claim 1, wherein the number of the high-pressure vessel is m (n + 2).   The saccharification / decomposition method for cellulosic biomass according to any one of claims 1 to 3, wherein the temperature in the decomposition step is 140 ° C or higher and 200 ° C or lower, and hemicellulose is decomposed into saccharides.   The slurry generated in the discharging step is subjected to solid-liquid separation, the solid content after hemicellulose is decomposed and dissolved in water is used as the slurry, the slurry after solid-liquid separation is used in the filling step, and the temperature of the decomposition step is set to 240. The method for saccharifying and decomposing cellulosic biomass according to claim 4, wherein the cellulose is decomposed into saccharides by adjusting the temperature to 280 ° C or higher.   The saccharification / decomposition method for cellulosic biomass according to any one of claims 1 to 3, wherein the temperature in the decomposition step is 240 ° C or higher and 280 ° C or lower, and cellulose is decomposed into saccharides.   The saccharification / decomposition method for cellulosic biomass according to any one of claims 1 to 6, wherein ethanol is added to the raw material slurry in an amount of 2 mol% to 10 mol% in the filling step. A saccharification / decomposition device for cellulosic biomass comprising a plurality of first low pressure vessels, high pressure vessels and second low pressure vessels,
The first low pressure vessel and the high pressure vessel are connected by a first connection path,
The high pressure vessel and the second low pressure vessel are connected by a second connection path,
The second low pressure vessel and the first low pressure vessel are connected by a flush path,
In the first low-pressure vessel, a filling step of pulverizing cellulosic biomass and filling with a slurry mixed with water, and a heating step of sealing and heating the first low-pressure vessel are performed,
The slurry after the temperature raising step is transferred from the first low pressure vessel to the high pressure vessel by the first connection path as the first transfer step,
In the high-pressure vessel, a decomposition process is performed in which cellulose and / or hemicellulose in cellulosic biomass is decomposed into sugars by the oxidizing power of high-temperature high-pressure water,
The slurry after the decomposition step is transferred from the high pressure vessel to the second low pressure vessel by the second transfer path as the second transfer step,
In the second low pressure vessel, a temperature lowering step for lowering the temperature by flash evaporation of the high temperature and high pressure slurry and a discharge step for taking out the slurry in the second pressure vessel are performed,
When a filling process is being executed in a certain first low pressure container, a discharging process is being executed in a certain second low pressure container, and the slurry filled in the first low pressure container during the filling process and the discharging process are executed. Heat exchange with the slurry discharged from the second low pressure vessel inside,
When the temperature raising process is being performed in the other first low pressure vessel, the temperature lowering process is being performed in the other second low pressure vessel, and the flash steam discharged from the second low pressure vessel during the temperature lowering process is being executed. A saccharification / decomposition apparatus for cellulosic biomass, wherein heat recovery is performed by supplying the first low-pressure pressure vessel during the temperature raising process through a flash path.   The saccharification / decomposition of cellulosic biomass according to claim 8, wherein all of the seven steps have the same required time, and the number of bases of the first low pressure vessel, the high pressure vessel and the second low pressure vessel is 3 m (m is a natural number). apparatus. When all the 6 steps other than the decomposition step have the same required time, and the required time for the decomposition step is n times (n is a natural number) the required time for the other 6 steps,
The base numbers of the first low pressure vessel and the second low pressure vessel are each 3 m (m is a natural number),
The saccharification / decomposition apparatus for cellulosic biomass according to claim 8, wherein the base number of the high-pressure vessel is m (n + 2).

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