JP2014057547A - Method of pretreating biomass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of pretreating biomass quickly and efficiently performing heating of a substrate mixture and cooling of ammonia evaporated from a pretreated ammonia-containing product for saccharification, at low cost.SOLUTION: In the method of pretreating biomass, a first heat medium and a second heat medium are supplied to a heat pump 19 to conduct heat exchange; the heated first heat medium is used to heat a substrate mixture; and the cooled second heat medium is used to cool ammonia. In a first bypass circulation path 15 and 21 provided to a first circulation path 15, the first heat medium is circulated, and the heated first heat medium is reserved, and the substrate mixture is heated with the first heat medium. In a second bypass circulation path 48 and 52 provided to a second circulation path 48, the second heat medium is circulated, and the cooled second heat medium is reserved, and the ammonia is cooled with the second heat medium.

Description

  The present invention relates to a biomass pretreatment method.

  In recent years, it has been studied to use a gasoline-ethanol mixed fuel as a fuel for automobiles. When bioethanol obtained by fermentation and distillation of plant substances is used as the ethanol, a so-called carbon neutral effect can be obtained by strict soil management, reducing carbon dioxide emissions and global warming. It is thought that it can contribute to prevention of

  However, when a crop such as sugar cane or corn is used as the plant substance, there is a problem that the supply amount as food or feed decreases because the crop is consumed in large quantities as a raw material for ethanol. Then, the technique which manufactures ethanol using the lignocellulosic biomass which does not become an edible or feed as said plant substance is examined.

  The lignocellulosic biomass contains cellulose, and saccharification is performed on the cellulose using a saccharifying enzyme to decompose it into sugars such as glucose, and ethanol can be obtained by fermenting the obtained glucose or the like.

  However, the lignocellulosic biomass mainly contains hemicellulose and lignin in addition to cellulose, and usually the cellulose and the hemicellulose are firmly bound to the lignin. It is difficult to carry out the reaction. Therefore, when enzymatically saccharifying the cellulose, it is desirable that the lignocellulosic biomass is pretreated in advance so that the enzymatic saccharification reaction is possible.

  In order to make the lignocellulosic biomass ready for an enzymatic saccharification reaction, a pretreatment for mixing the lignocellulosic biomass as a substrate with ammonia water to form a substrate mixture and holding the substrate mixture at a predetermined temperature for a predetermined time The method is known. According to the pretreatment method, lignin is dissociated from the substrate or the substrate is swollen, whereby the lignocellulosic biomass as the substrate can be brought into a state capable of enzymatic saccharification reaction.

  In addition, in this application, dissociation means cut | disconnecting at least one part coupling | bonding among the binding sites of lignin couple | bonded with cellulose etc. Swelling means that voids are formed in cellulose or the like constituting crystalline cellulose by the ingress of liquid, or the voids are generated inside the cellulose fibers to expand.

  Further, the ammonia water can be recovered by cooling and condensing gaseous ammonia separated from the substrate mixture after the pretreatment and dissolving it in water.

  Therefore, in the pretreatment method, the heat medium is heated using a heat pump with the heat of condensation when the ammonia is condensed and the heat of dissolution when the ammonia is dissolved in water, and the substrate mixture is heated using the heat medium. Has been proposed (see, for example, Patent Document 1).

JP 2010-142680 A

  On the other hand, the heat medium for heating the substrate mixture is the first heat medium, and the heat medium for recovering the heat of condensation when the ammonia is condensed and the heat of dissolution when it is dissolved in water is the second heat medium. It is conceivable to supply the second heat medium to a heat pump that heats the first heat medium. In this case, the substrate mixture can be heated using the heated first heat medium by heat exchange between the first heat medium and the second heat medium, and the cooled second heat medium can be cooled. The ammonia can be cooled using the heat medium.

  However, when the conventional pretreatment method is carried out batchwise, it requires a large amount of heat energy to heat the substrate mixture to a predetermined temperature, and a low temperature and a small amount of the first heat at the start of the heat pump. There is a disadvantage that it is difficult to quickly heat the medium to the predetermined temperature.

  Further, in the batch system, the ammonia released and separated from the ammonia-containing saccharification pretreatment product immediately after completion of the pretreatment of the substrate mixture becomes a high concentration and a large amount. As a result, there is a disadvantage that a large amount of cooling energy is required for cooling the high concentration and a large amount of ammonia, and it is difficult to quickly cool with a high temperature and a small amount of the second heat medium when starting the heat pump.

  In order to solve the inconvenience, it is conceivable to increase the size of the heat pump itself or to provide another heat source or cooling means. However, when doing so, an increase in equipment cost is inevitable.

  In addition, once the substrate mixture is heated to a predetermined temperature, thereafter, the heat energy maintained at the temperature becomes smaller than the heat energy required for heating to the predetermined temperature. Similarly, when the time immediately after the end of the pretreatment is over, the concentration and generation amount of ammonia are reduced, and the cooling heat energy required for cooling is reduced. Therefore, if the equipment is enlarged in order to cope with the state immediately after the pretreatment of the substrate mixture is completed, there is a disadvantage that the operation cost increases.

  The present invention eliminates such inconvenience, and can quickly and efficiently perform heating until the substrate mixture reaches the predetermined temperature, and immediately after the pretreatment of the substrate mixture is completed. It is an object of the present invention to provide a biomass pretreatment method capable of quickly and efficiently cooling a large concentration and a large amount of ammonia released from an ammonia-containing saccharification pretreatment product.

  In order to achieve this object, the present invention comprises a step of mixing a lignocellulosic biomass and ammonia water as a substrate in a batch system to obtain a substrate mixture, heating the substrate mixture to a predetermined temperature, and For a predetermined period of time to dissociate lignin from the substrate or swell the substrate to obtain an ammonia-containing saccharification pretreatment product, and to release ammonia from the ammonia-containing saccharification pretreatment product to separate ammonia. A process for obtaining a pre-treated product for ammonia separation and saccharification, and a step for cooling and condensing ammonia released from the pretreatment product for saccharification containing ammonia and dissolving it in water to obtain ammonia water and recovering the ammonia water, A first heat medium for heating the substrate mixture, a heat of condensation for condensing the ammonia, and a heat of dissolution for dissolving in water. The second heat medium to be collected is supplied to a heat pump, and the substrate mixture is heated using the heated first heat medium by heat exchange between the first heat medium and the second heat medium in the heat pump. And in the biomass pretreatment method for cooling the ammonia using the cooled second heat medium, the first heat medium is circulated between the heat pump and the portion for heating the substrate mixture. A first bypass circulation path is provided in the path to circulate to the heat pump, bypassing a portion that heats the substrate mixture, and the first heat medium is circulated to the first bypass circulation path to thereby achieve the predetermined temperature. A predetermined amount of the first heat medium heated to a higher temperature and heated to a temperature higher than the predetermined temperature is stored in advance, and the predetermined temperature is maintained until the substrate mixture reaches the predetermined temperature. Higher A portion for cooling the ammonia in a second circulation path for heating the substrate mixture with the first heating medium heated to circulate the second heating medium between the heat pump and the portion for cooling the ammonia. When a second bypass circulation path for bypassing and circulating to the heat pump is provided, and the second heat medium is circulated to the second bypass circulation path by circulating the second heat medium to the second circulation path. A predetermined amount of the second heat medium that is cooled to a temperature lower than the temperature of the water and cooled to a temperature lower than the temperature at which it is circulated through the second circulation path is stored in advance, and the ammonia-containing saccharification pretreatment product The second ammonia is cooled to a temperature lower than the temperature at which the ammonia is circulated through the second circulation path until the ammonia concentration to be diffused decreases to a predetermined concentration and the ammonia amount decreases to a predetermined amount. By heat medium The ammonia is cooled.

  The pretreatment method of the present invention is a batch type, and first, lignocellulosic biomass as a substrate and aqueous ammonia are mixed to obtain a substrate mixture.

  Next, by holding the substrate mixture at a predetermined temperature for a predetermined time, lignin is dissociated from the substrate or the substrate is swollen to obtain an ammonia-containing saccharification pretreatment product. The ammonia-containing saccharification pretreatment product is pretreated so that the lignocellulosic biomass as the substrate can undergo an enzymatic saccharification reaction, but has a high pH because it contains ammonia. It cannot be served.

  Therefore, next, ammonia is diffused and separated from the ammonia-containing saccharification pre-treatment product, while the diffused ammonia is cooled and condensed and dissolved in water to form ammonia water, which is recovered. As a result, an ammonia separation pretreatment product from which ammonia has been separated can be obtained, and the ammonia separation pretreatment product can be subjected to an enzymatic saccharification reaction.

  Here, in the present invention, the substrate mixture is heated by the first heat medium, while the heat of condensation when the ammonia is condensed by the second heat medium and the heat of dissolution when dissolved in water are recovered. The first heat medium and the second heat medium are supplied to a heat pump, and heat exchange is performed between the first heat medium and the second heat medium by the heat pump, whereby the first heat medium is While being heated, the second heat medium is cooled.

  By the way, since the pretreatment method of the present invention is a batch system, not only the substrate mixture but also the apparatus itself is not heated at the initial stage of heating the substrate mixture, so that the substrate mixture is heated to a predetermined temperature. Large heat energy is required.

  Therefore, in the pretreatment method of the present invention, the first heating medium is circulated between the heat pump and the portion for heating the substrate mixture, and the portion for heating the substrate mixture is bypassed to the first circulation path. A first bypass circulation path that circulates through the heat pump is provided, and the first heat medium is circulated through the first bypass circulation path. If it does in this way, since a heat energy will not be lost by the heating of the said substrate mixture, the said 1st heat medium will be heated up gradually to high temperature.

  Then, as described above, the first heat medium is heated to a temperature higher than the predetermined temperature, and a predetermined amount of the heated first heat medium is stored in advance, and the substrate mixture is stored in the predetermined temperature. The substrate mixture is heated by the heated first heating medium until the temperature is reached.

  According to the pretreatment method of the present invention, by doing so, heating until the substrate mixture reaches the predetermined temperature is promptly performed, and the heating pump itself is provided with another heat source. It can be carried out efficiently at low cost without increasing the size.

  Further, since the pretreatment method of the present invention is a batch type, immediately after the pretreatment of the substrate mixture, a large amount of ammonia is released from the ammonia-containing saccharification pretreatment product, and the ammonia is cooled. In order to do so, a large amount of cooling energy is required.

  Therefore, in the pretreatment method of the present invention, the second heat medium is circulated between the heat pump and the portion that cools the ammonia, and the portion that cools the ammonia is bypassed to the heat pump. A second bypass circulation path to be circulated is provided, and the second heat medium is circulated through the second bypass circulation path. In this case, the second heat medium is gradually cooled to a lower temperature because the cooling energy is not lost by the cooling of the ammonia.

  Therefore, as described above, the second heat medium is cooled to a temperature lower than the temperature at which the second heat medium is circulated through the second circulation path, and a predetermined amount of the cooled second heat medium is stored in advance. The ammonia is released by the second heat medium cooled until the concentration of ammonia released from the ammonia-containing saccharification pretreatment product is lowered to a predetermined concentration and the amount of ammonia is lowered to the predetermined amount. Cool down.

  According to the pretreatment method of the present invention, in this way, the concentration of ammonia released from the ammonia-containing saccharification pretreatment product is reduced to a predetermined concentration, and the amount of ammonia is reduced to a predetermined amount. Can be quickly and efficiently performed at low cost without providing other cooling means or increasing the size of the heat pump itself.

  In the pretreatment method of the present invention, the heat pump may use a single heat medium, but by using a binary heat pump including two kinds of heat medium, the cooling of the ammonia is more efficient. Can be done well.

  In the pretreatment method of the present invention, the storage of the first heat medium heated to a temperature higher than the predetermined temperature can be performed, for example, during the step of obtaining the substrate mixture. In addition, the storage of the second heat medium cooled to a temperature lower than the temperature when circulating through the second circulation path is performed, for example, between the step of obtaining the substrate mixture and the step of obtaining the ammonia-containing saccharification pretreatment product. Can be done.

  In addition, since the pretreatment method of the present invention is a batch type, after the step of obtaining the ammonia separation saccharification pretreatment product in one reaction vessel is completed, the next step of obtaining the substrate mixture is started. Since operations such as washing of the reaction vessel are required, it takes a considerable amount of time. In the meantime, since the pretreatment method cannot be carried out in the reaction vessel, sufficient treatment efficiency cannot be obtained.

  Therefore, in the pretreatment method of the present invention, a plurality of reaction vessels are provided for performing the step of obtaining the substrate mixture, the step of obtaining the ammonia-containing saccharification pretreatment product, and the step of obtaining the ammonia separation saccharification pretreatment product. A step of obtaining the substrate mixture in at least one other reaction vessel until the step of obtaining the ammonia separation saccharification pretreatment product in one reaction vessel is completed and the step of obtaining the next substrate mixture is started; A step of obtaining an ammonia-containing saccharified pre-treated product and a step of obtaining the ammonia-separated saccharified pre-treated product are provided, the first circulation path is provided for each reaction vessel, and a first bypass circulation common to each reaction vessel It is preferable to provide a route.

  In this way, after the step of obtaining the ammonia separation saccharification pretreatment product in one reaction vessel is completed, the pretreatment is performed in another reaction vessel before the step of obtaining the next substrate mixture is started. And the processing efficiency can be improved.

  At this time, the first circulation path is provided for each reaction vessel, and a common first bypass circulation path is provided for each reaction vessel, and the first bypass circulation path is heated to a temperature higher than the predetermined temperature. A predetermined amount of the first heat medium is stored in advance. The apparatus configuration can be simplified by supplying the first heat medium heated to a temperature higher than the predetermined temperature to each reaction vessel through each first circulation path, thereby further improving the processing efficiency. Can be made.

  When doing the above, for example, a step of obtaining the substrate mixture in another reaction vessel while ammonia is released from the ammonia-containing pre-saccharification product obtained in one reaction vessel is performed simultaneously with the predetermined It is possible to store the first heat medium heated to a temperature higher than this temperature.

  In the above process, since the heat pump can be operated continuously, the heat pump can be operated more efficiently and energy consumption can be reduced.

The system block diagram which shows the example of 1 structure of the apparatus which implements the pre-processing method of this embodiment. Explanatory drawing which shows schematically an example of the line of the binary system heat pump shown in FIG. The system block diagram which shows the other structural example of the apparatus which implements the pre-processing method of this embodiment.

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

  The pre-processing method of this embodiment can be implemented using the pre-processing apparatus 1 shown in FIG. 1, for example. The pretreatment device 1 includes a reaction vessel 2, an ammonia condenser 3, an ammonia absorption tower 4, and an ammonia tank 5.

  The reaction vessel 2 is provided with a substrate supply conduit 6 and an ammonia water supply conduit 7 at the top, and a first exhaust conduit 8 for discharging ammonia gas and guiding it to the ammonia condenser 3 is connected to an exhaust valve 9. It is arranged via the bag filter 10. The substrate supply conduit 6 supplies lignocellulosic biomass as a substrate, such as rice straw, to the reaction vessel 2, and the ammonia water supply conduit 7 supplies ammonia water to the reaction vessel 2 from an ammonia water tank (not shown).

  The reaction vessel 2 also includes a motor 11 disposed at the top, a rotary shaft 12 that hangs down from the motor 11 into the reaction vessel 2, and a stirring blade 13 that extends from the rotary shaft 12 in the horizontal direction. In addition, a jacket 14 through which a heat medium is circulated is provided. A hot water conduit 15 is connected to the jacket 14.

  The hot water conduit 15 supplies hot water as a first heat medium derived from the upper part of the jacket 14 to a hot water primary tank 16, a hot water primary pump 17, an air cooling fan 18, a two-way heat pump 19, and a first switching valve 20. And is circulated to the bottom of the jacket 14. As a result, a first circulation path is formed by the hot water conduit 15.

  A warm water bypass conduit 21 is connected to the first switching valve 20, and the other end of the warm water bypass conduit 21 is connected to the warm water primary tank 16 via a second switching valve 22. As a result, the first bypass valve 20, the hot water bypass conduit 21, the second switch valve 22, the hot water primary tank 16, and the hot water conduit 15 from the hot water primary tank 16 to the first switch valve 20 provide the first bypass. A circulation path is formed.

  A high temperature water conduit 23 is connected to the second switching valve 22, and the other end of the high temperature water conduit 23 is connected to the hot water secondary tank 24. The 1st switching valve 20 and the 2nd switching valve 22 switch the flow path of warm water according to the temperature detected by the 1st temperature sensor 25 provided in the binary system heat pump 19, respectively.

  The hot water secondary tank 24 is provided with a high temperature water supply conduit 26, and the high temperature water supply conduit 26 is connected to the hot water conduit 15 on the downstream side of the first switching valve 20 via the hot water secondary pump 27. . The hot water primary tank 16 is provided with a first make-up water conduit 28, and the first make-up water conduit 28 is connected to the first make-up water tank 30 through a first water supply valve 29.

  The ammonia condenser 3 condenses liquid ammonia by cooling at least a part of the ammonia gas introduced from the first exhaust conduit 8, and the first exhaust conduit 31 for discharging the condensed ammonia is provided. I have. The first drainage conduit 31 is connected to the ammonia tank 5 via a condensation tank 32 and a first drainage pump 33 for further cooling the condensed ammonia.

  The ammonia condenser 3 includes a second exhaust conduit 34 that discharges ammonia gas that has not been condensed and guides the ammonia gas to the ammonia tank 5. The second exhaust conduit 34 is connected to the ammonia tank 5 via an on-off valve 35. It is connected. The second exhaust conduit 34 branches from the third exhaust conduit 36 upstream of the on-off valve 35, and the third exhaust conduit 36 includes a vacuum pump 37 on the way, and joins the second exhaust conduit 34 downstream of the on-off valve 35. doing.

  The ammonia absorption tower 4 communicates with the top surface of the ammonia tank 5 at the bottom, and absorbs (dissolves) the ammonia gas guided to the ammonia tank 5 by the second exhaust conduit 34 in the ammonia water. For this reason, the ammonia absorption tower 4 is provided with a showering device 39 for showering the ammonia water supplied from the ammonia tank 5 via the ammonia water circulation conduit 38.

  The ammonia water circulation conduit 38 is connected from the ammonia tank 5 to the showering device 39 via the circulation pump 40, the ammonia water heat exchanger 41, and the ammonia concentration sensor 42. The ammonia water heat exchanger 41 has a function of cooling the ammonia water circulated through the ammonia water circulation conduit 38. The ammonia absorption tower 4 is provided with a second makeup water conduit 43, and the second makeup water conduit 43 is connected to a second makeup water tank 45 via a second water supply valve 44.

  The ammonia tank 5 includes a second drainage conduit 46 for discharging ammonia water, and the second drainage conduit 46 is connected to an ammonia water tank (not shown) via a second drainage pump 47.

  The ammonia condenser 3 is connected to a low-temperature water conduit 48 for cooling the ammonia gas introduced from the first exhaust conduit 8. The low-temperature water conduit 48 converts low-temperature water derived from the ammonia condenser 3 as a second heat medium into a low-temperature water primary tank 49, a low-temperature water primary pump 50, a two-way heat pump 19, a third switching valve 51, ammonia. The water is circulated to the ammonia condenser 3 through the water heat exchanger 41 and the condensation tank 32. As a result, the low-temperature water conduit 48 forms a second circulation path.

  A low temperature water bypass conduit 52 is connected to the third switching valve 51, and the other end of the low temperature water bypass conduit 52 is connected to the low temperature water primary tank 49 via the fourth switching valve 53. As a result, the third switching valve 51, the low temperature water bypass conduit 52, the fourth switching valve 53, the low temperature water primary tank 49, and the low temperature water conduit 48 from the low temperature water primary tank 49 to the third switching valve 51, A second bypass circulation path is formed.

  A cold water conduit 54 is connected to the fourth switching valve 53, and the other end of the cold water conduit 54 is connected to the low temperature water secondary tank 55. The third switching valve 51 and the fourth switching valve 53 switch the flow path of the low-temperature water according to the temperature detected by the second temperature sensor 56 provided in the binary heat pump 19.

  The low temperature water secondary tank 55 is provided with a cold water supply conduit 57, and the cold water supply conduit 57 is connected to the low temperature water conduit 48 downstream of the third switching valve 51 via the low temperature water secondary pump 58. Yes. The low temperature water primary tank 49 is provided with a third make-up water conduit 59, and the third make-up water conduit 59 is connected to the third make-up water tank 61 through the third water supply valve 60.

  Next, the operation of the pretreatment device 1 of this embodiment will be described.

  In the pretreatment device 1, first, the ammonia separation saccharification pretreatment product obtained in the previous treatment is discharged from the discharge port (not shown) at the bottom of the reaction vessel 2 and transferred to the next step. Thereafter, the inside of the reaction vessel 2 is washed, and a lignocellulosic biomass, for example, rice straw, as a new substrate is supplied from the substrate supply conduit 6 to the reaction vessel 2, and ammonia water is supplied from the ammonia water supply conduit 7 to the reaction vessel. 2 is supplied.

  At this time, in the reaction vessel 2, the rotating shaft 12 is rotationally driven by the motor 11, and the rice straw and the ammonia water are stirred by the stirring blade 13, whereby the substrate mixed solution is prepared. In the present embodiment, the period from when a new substrate and aqueous ammonia are supplied to the reaction vessel 2 and mixed to obtain a substrate mixture corresponds to the step of obtaining the substrate mixture.

  The substrate mixed solution is heated to a predetermined temperature, for example, a temperature in the range of 80 to 85 ° C. in the reaction vessel 2 by the hot water supplied from the hot water conduit 15 to the jacket 14 as the first heat medium. Hold for a predetermined time. As a result, it is possible to obtain an ammonia-containing saccharification pretreatment product in which lignin is dissociated from the substrate or the substrate is swollen so that rice straw as the substrate can be enzymatically saccharified. In this embodiment, the said operation | movement corresponds to the process of obtaining an ammonia containing saccharification pre-processing thing.

  Next, in the pretreatment device 1, the ammonia contained in the ammonia-containing saccharification pretreatment product is diffused as a gas by opening the exhaust valve 9, and ammonia is condensed from the first exhaust conduit 8 through the bag filter 10. Guide to vessel 3. At this time, the pressure in the reaction vessel 2 is higher than the atmospheric pressure due to the heating, and by opening the exhaust valve 9, ammonia gas can be easily diffused from the ammonia-containing pre-saccharification product.

  The ammonia gas is cooled by low-temperature water supplied from the low-temperature water conduit 48 to the ammonia condenser 3 as a second heat medium, and a part of the ammonia gas is condensed and liquefied to form liquid ammonia. To the condensing tank 32. The liquid ammonia is further cooled by the low-temperature water supplied from the low-temperature water conduit 48 in the condensing tank 32 and then sent to the ammonia tank 5 via the first drainage pump 33. At the same time, the condensation heat generated when the ammonia gas is condensed in the ammonia condenser 3 and the condensation tank 32 is recovered by the low-temperature water flowing through the low-temperature water conduit 48.

  Further, the remaining part of the ammonia gas is introduced into the ammonia tank 5 through the second exhaust conduit 34 by opening the on-off valve 35. The pressure of the ammonia gas decreases as it is diffused, and when it becomes equal to atmospheric pressure, it becomes difficult to dissipate further. Therefore, in the pretreatment device 1, when the ammonia gas pressure becomes equal to the atmospheric pressure, the on-off valve 35 is closed and the vacuum pump 37 is operated to suck the ammonia in the reaction vessel 2, 2 is introduced into the ammonia tank 5 through the exhaust pipe 34 and the third exhaust pipe 36.

  In the reaction vessel 2, the ammonia-separated saccharification pretreatment product from which ammonia has been separated can be obtained as a result of the ammonia being diffused from the ammonia-containing saccharification pretreatment product as described above. In this embodiment, the said operation | movement corresponds to the process of obtaining the ammonia separation saccharification pre-processing thing.

  The ammonia separation saccharification pretreatment product is discharged from the discharge port (not shown) at the bottom of the reaction vessel 2 as described above and transferred to the next step. Then, the next process is prepared in the reaction vessel 2.

  On the other hand, the ammonia gas introduced into the ammonia tank 5 is then introduced into the ammonia absorption tower 4 communicating with the ammonia tank 5. In the ammonia absorption tower 4, the ammonia water circulated through the ammonia water circulation conduit 38 by the circulation pump 40 is showered from the showering device 39, thereby absorbing (dissolving) the ammonia gas in the ammonia water.

  In this embodiment, the condensation of the ammonia gas in the ammonia condenser 3 and the absorption (dissolution) in the ammonia absorption tower 4 correspond to a process of recovering the diffused ammonia as ammonia water.

  At this time, an ammonia water heat exchanger 41 is provided in the middle of the ammonia water circulation conduit 38, and the ammonia water flowing through the ammonia water circulation conduit 38 is cooled by exchanging heat with the low temperature water flowing through the low temperature water conduit 48. Is done. At the same time, the heat of dissolution generated when the ammonia gas is absorbed (dissolved) in the ammonia water is recovered by the low-temperature water flowing through the low-temperature water conduit 48.

  The ammonia water circulation conduit 38 is provided with an ammonia concentration sensor 42 for detecting the ammonia concentration of the ammonia water circulated through the ammonia water circulation conduit 38. When the ammonia concentration detected by the ammonia concentration sensor 42 becomes a predetermined value, for example, the concentration of the ammonia water supplied to the reaction vessel 2, the second water supply valve 44 is opened, and the second makeup water tank Pure water is supplied to the ammonia absorption tower 4 from 45 through the second supply water conduit 43. As a result, the concentration of ammonia water stored in the ammonia tank 5 can be maintained at a predetermined value, for example, the concentration of ammonia water supplied to the reaction vessel 2.

  The ammonia water stored in the ammonia tank 5 is cooled to a temperature in the range of 15 to 20 ° C., for example, as a result of condensation and cooling in the ammonia condenser 3 and the condensation tank 32 and dissolution in the ammonia water in the ammonia absorption tower 4. Has been. The ammonia water cooled to the temperature in the above range is taken out by the second drainage pump 47 through the second drainage conduit 46 and sent to an ammonia water tank (not shown) to prepare the substrate mixed solution in the reaction vessel 2. Reused.

  Next, the heating of the substrate mixture in the reaction vessel 2 and the cooling of the ammonia gas in the ammonia condenser 3 and the ammonia absorption tower 4 will be described in more detail.

  In the pretreatment device 1, during the step of obtaining the substrate mixture, the first switching valve 20 is switched to connect the hot water conduit 15 and the hot water bypass conduit 21, and the hot water primary pump 17, the air cooling fan 18, and The binary heat pump 19 is activated. The hot water bypass conduit 21 is connected upstream and downstream by a second switching valve 22.

  In this way, the hot water stored in the hot water primary tank 16 is passed through the hot water conduit 15 through the hot water primary pump 17, the air cooling fan 18, the two-way heat pump 19, the first switching valve 20, and the hot water bypass conduit 21. Then, it is circulated through the first bypass circulation path that returns to the hot water primary tank 16. Here, the hot water is cooled by the air cooling fan 18 and then heated by exchanging heat with the heat medium of the binary heat pump 19 in the binary heat pump 19.

  Further, the third switching valve 51 is switched so as to connect the low-temperature water conduit 48 and the low-temperature water bypass conduit 52, and the low-temperature water primary pump 50 is operated. The low temperature water bypass conduit 52 is connected upstream and downstream by a fourth switching valve 53.

  In this way, the low temperature water stored in the low temperature water primary tank 49 is transferred to the low temperature water primary pump 50, the two-way heat pump 19, the third switching valve 51, and the low temperature water bypass conduit 52 by the low temperature water conduit 48. And then circulated through the second bypass circulation path returning to the low temperature water primary tank 49. Here, the low-temperature water is cooled by exchanging heat with a heat medium in the binary heat pump 19.

  The two-way heat pump 19 is a heat pump using two types of heat medium, and includes two types of heat medium circulation systems of a first circulation conduit 71 and a second circulation conduit 72 as shown in FIG. ing. As the two types of heat medium, for example, tetrafluoroethane (R134a) is circulated in the first circulation conduit 71, and pentafluoropropane (R245fa) is circulated in the second circulation conduit 72.

  The first circulation conduit 71 is a pentagon that is circulated to the expansion valve 73 and the first heat exchanger 74 that exchanges heat with the low-temperature water circulated to the low-temperature water conduit 48, the compressor 75, and the second circulation conduit 72. A second heat exchanger 76 that exchanges heat with fluoropropane (R245fa) is provided. The second circulation conduit 72 includes an expansion valve 77 and a second heat exchanger 76 for exchanging heat with tetrafluoroethane (R134a) circulated to the first circulation conduit 71 along the way, a compressor 78, and a hot water conduit 15. A third heat exchanger 79 for exchanging heat with the hot water circulated is provided.

  Here, the low-temperature water is cooled by exchanging heat with tetrafluoroethane (R134a) in the first heat exchanger 74 of the binary heat pump 19. The tetrafluoroethane (R134a) is heated by exchanging heat with the low-temperature water in the first heat exchanger 74, compressed by the compressor 75 and further heated, and then supplied to the second heat exchanger 76. Heat exchange with pentafluoropropane (R245fa) circulated through the second circulation conduit 72. The tetrafluoroethane (R134a) is cooled by the heat exchange, is adiabatically expanded by the expansion valve 73, is further cooled, and is then returned to the first heat exchanger 74.

  The pentafluoropropane (R245fa) is heated by exchanging heat with the tetrafluoroethane (R134a) in the second heat exchanger 76, compressed by the compressor 75, and further heated to a third heat exchange. Heat is exchanged with the hot water supplied to the vessel 79 and circulated through the hot water conduit 15. The pentafluoropropane (R245fa) is cooled by the heat exchange, then adiabatically expanded by the expansion valve 77 and further cooled, and then returned to the second heat exchanger 76. The hot water is heated by exchanging heat with the pentafluoropropane (R245fa) in the third heat exchanger 79.

  In other words, the operation of the binary heat pump 19 is that the low-temperature water is used as the second heat medium for recovering the heat of condensation and the heat of dissolution of the ammonia, and the first heat medium for heating the substrate mixture is used as the first heat medium. The hot water is supplied to a binary heat pump 19, the first heat medium and the second heat medium are exchanged via the binary heat pump 19, and the first heat medium is heated and the second heat medium is heated. This corresponds to cooling the heat medium.

  According to the binary heat pump 19, it is possible to reduce the compression ratio of each of the two types of heat mediums of the tetrafluoroethane (R134a) and the pentafluoropropane (R245fa). Therefore, as compared with the case where a single heat medium is used, the warm water as the first heat medium circulated through the hot water conduit 15 and the second heat medium as the second heat medium circulated through the low temperature water conduit 48 are used. Both the cooling of the low-temperature water can be efficiently performed.

  The hot water as the first heat medium circulated through the hot water conduit 15 is not sufficiently heated immediately after the start of the binary heat pump 19, but bypasses the reaction vessel 2 by the first bypass circulation path. Thus, the temperature is gradually raised with the passage of time. Therefore, in the pretreatment device 1, the first temperature sensor 25 is provided in the hot water conduit 15 on the secondary side of the binary heat pump 19 to detect the temperature of the hot water.

  The temperature of the hot water detected by the first temperature sensor 25 is, for example, 90 to 95 ° C., which is higher than a predetermined temperature (for example, a temperature in the range of 80 to 85 ° C.) at which the substrate mixture is heated in the reaction vessel 2. When heated to a temperature in the range, the second switching valve 22 is switched to connect the hot water bypass conduit 21 and the hot water conduit 23. As a result, hot water having a temperature in the above range (hereinafter referred to as high temperature water) is stored in the hot water secondary tank 24.

  The hot water is stored throughout the step of obtaining the substrate mixture. During this time, when the water level sensor (not shown) detects that the water level of the high-temperature water stored in the hot water secondary tank 24 has reached the upper limit, the second switching valve 22 is connected to the upstream side of the hot water bypass conduit 21. The high-temperature water is circulated to the hot water primary tank 16.

  When the hot water stored in the hot water secondary tank 24 is insufficient, the first water supply valve 29 is opened, and the hot water 1 is supplied from the first make-up water tank 30 through the first make-up water conduit 28. The next tank 16 is supplied with pure water.

  Next, when the preparation of the substrate mixture is completed and the substrate mixture is heated to a predetermined temperature, the hot water bypass conduit 21 and the hot water conduit 23 are connected by the second switching valve 22. Then, the hot water secondary pump 27 is operated. In this way, the high temperature water stored in the hot water secondary tank 24 is supplied to the jacket 14 of the reaction vessel 2 via the high temperature water supply conduit 26 and the hot water conduit 15, and the substrate mixture becomes the predetermined temperature. Heating up to reaching can be performed quickly.

  Next, if it is detected by a water level sensor (not shown) that the level of the high-temperature water stored in the hot water secondary tank 24 has reached the lower limit, the first switching valve 20 is set upstream of the hot water conduit 15. It is switched so as to connect the downstream. And the warm water led out from the upper part of the jacket 14 is warmed by the warm water conduit 15 which is the 1st circulation path, the warm water primary tank 16, the warm water primary pump 17, the air cooling fan 18, the two-way system heat pump 19, and 1st switching. A normal heating state is circulated through the valve 20 to the bottom of the jacket 14.

  As a result, the substrate mixture is maintained at the predetermined temperature only by the heat energy supplied by the warm water in the normal heating state, and heating is continued.

  On the other hand, the low-temperature water as the second heat medium circulated through the low-temperature water conduit 48 is not sufficiently cooled immediately after the start of the two-way heat pump 19, but is not ammonia by the second bypass circulation path. Since it circulates around the condenser 3 and the ammonia absorption tower 4, the temperature is gradually lowered with time. Therefore, in the pretreatment device 1, the second temperature sensor 56 is provided in the low-temperature water conduit 48 on the secondary side of the binary heat pump 19 to detect the temperature of the low-temperature water.

  If the temperature of the low-temperature water detected by the second temperature sensor 56 is cooled to a temperature lower than the temperature at which the ammonia gas can be condensed by the ammonia condenser 3, the fourth switching valve 53 is connected to the low-temperature water bypass. It is switched to connect the conduit 52 and the cold water conduit 54. As a result, low temperature water (hereinafter referred to as cold water) cooled to a temperature lower than the temperature at which ammonia gas can be condensed by the ammonia condenser 3, for example, in the range of 10 to 15 ° C. is stored in the low temperature water secondary tank 55. Is done.

  The cold water is stored between the step of obtaining the substrate mixture and the step of obtaining the ammonia-containing saccharification pretreatment product. During this time, when the water level sensor (not shown) detects that the water level of the cold water stored in the low temperature water secondary tank 55 has reached the upper limit, the fourth switching valve 53 is located upstream of the low temperature water bypass conduit 52. Are switched to connect the downstream and the downstream, and the cold water is circulated to the low temperature water primary tank 49.

  When the cold water stored in the low temperature water secondary tank 55 is insufficient, the third water supply valve 60 is opened, and the low temperature water is supplied from the third makeup water tank 61 via the third makeup water conduit 59. Pure water is supplied to the primary tank 49.

  Next, the ammonia-containing saccharification pretreatment product is obtained in the reaction vessel 2, the exhaust valve 9 is opened, and the ammonia gas released from the ammonia-containing saccharification pretreatment product is introduced into the ammonia condenser 3. If it reaches, the low temperature water secondary pump 58 is operated in a state where the low temperature water bypass conduit 52 and the cold water conduit 54 are connected by the fourth switching valve 53. In this way, the cold water stored in the low temperature water secondary tank 55 passes through the cold water supply conduit 57 and the low temperature water conduit 48, passes through the ammonia water heat exchanger 41, and the condensation tank 32, and then the Ammore condenser. 3 is supplied. As a result, it is possible to quickly cool a large concentration and a large amount of ammonia gas released from the ammonia-containing saccharification pretreatment product.

  At this time, by setting the flow rate of the low-temperature water secondary pump 58 to be larger than the flow rate of the low-temperature water primary pump 50, the ammonia condenser 3 is more effective than the case where low-temperature water is circulated using only the normal low-temperature water conduit 48. Since the quantity of the cold water supplied to can be enlarged, it is preferable.

  The cold water supplied to the ammonia condenser 3 is used for cooling the ammonia gas and then discharged through a low-temperature water conduit 48. Then, after being supplied from the low temperature water primary pump 50 to the binary heat pump 19 and recooled, it is returned to the low temperature water secondary tank 55 via the low temperature water bypass conduit 52 and the cold water conduit 54.

  However, since the flow rate of the low temperature water secondary pump 58 is larger than the flow rate of the low temperature water primary pump 50, the amount of cold water stored in the low temperature water secondary tank 55 gradually decreases. Therefore, if it is detected by a water level sensor (not shown) that the water level of the cold water stored in the low temperature water secondary tank 55 has reached the lower limit, the third switching valve 51 is located upstream of the low temperature water conduit 48. It is switched so as to connect the downstream.

  Then, the low-temperature water derived from the ammonia condenser 3 is supplied to the low-temperature water primary tank 49, the low-temperature water primary pump 50, the two-way heat pump 19, and the third switching by the low-temperature water conduit 48 which is the second circulation path. The normal cooling state circulated through the ammonia condenser 3 is made via the valve 51, the ammonia water heat exchanger 41, and the condensation tank 32. At this time, since the concentration and amount of the ammonia gas to be diffused have already been reduced, the ammonia gas can be sufficiently cooled and condensed by the low-temperature water in the normal cooling state.

  The pretreatment device 1 shown in FIG. 1 includes only one reaction vessel 2 as described above. However, since the pretreatment method of the present embodiment is a batch type, after the step of obtaining the ammonia separation saccharification pretreatment product in the reaction vessel 2 is completed, the substrate or the like attached to the reaction vessel 2 is removed, or the reaction vessel The operation | work which wash | cleans 2 itself is needed. Therefore, when only one reaction vessel 2 is provided, a considerable time is required until the next step of obtaining the substrate mixture is started, and during this time, the pretreatment may be performed in the reaction vessel 2. Therefore, sufficient processing efficiency cannot be obtained.

  Therefore, the pretreatment device 1 may include a plurality of reaction vessels 2, for example, two reaction vessels 2a and 2b as shown in FIG. The reaction vessels 2a and 2b are respectively connected to the jacket 14 with hot water conduits 15a and 15b, and are provided with first exhaust conduits 8a and 8b for discharging ammonia gas and guiding it to the ammonia condenser 3, respectively. 2 has exactly the same configuration. Therefore, in FIG. 3, configurations of the reaction vessels 2 a and 2 b other than the hot water conduits 15 a and 15 b and the first exhaust conduits 8 a and 8 b are omitted.

  In the pretreatment device 1 shown in FIG. 3, the hot water conduits 15a and 15b are branched from the hot water conduit 15 by a fifth switching valve 62 provided downstream of the junction of the hot water conduit 15 and the hot water supply conduit 26, respectively. It is connected to the bottom of the jacket 14 of the reaction vessel 2a, 2b. The hot water conduits 15 a and 15 b led out from the upper portions of the jackets 14 of the reaction vessels 2 a and 2 b are joined by the sixth switching valve 63 to become the hot water conduit 15 and connected to the hot water primary tank 16.

  As a result, the first circulation path is formed by the hot water conduits 15 and 15a in the reaction vessel 2a, and the first circulation path is formed by the hot water conduits 15 and 15b in the reaction vessel 2b. On the other hand, the first bypass circulation path is common to the reaction vessels 2a and 2b.

  The first exhaust conduits 8 a and 8 b are joined by the seventh switching valve 64 to become the first exhaust conduit 8 and are connected to the ammonia condenser 3.

  Next, the operation of the pretreatment device 1 shown in FIG. 3 will be described.

  In the pretreatment device 1 shown in FIG. 3, first, the fifth switching valve 62 and the sixth switching valve 63 connect the hot water conduit 15 and the hot water conduit 15a, and the seventh switching valve 64 connects the first exhaust conduit 8 and the first With the exhaust conduit 8a connected, the substrate and ammonia water are supplied to the reaction vessel 2a. Then, the substrate is pretreated in the same manner as the pretreatment apparatus 1 shown in FIG. 1 except that the reaction vessel 2a is used instead of the reaction vessel 2. In the meantime, in the reaction container 2b, the removal of the substrate residue and the cleaning of the reaction container 2b itself in the previous pretreatment are performed.

  Next, in the reaction vessel 2a, if the step of obtaining the ammonia-containing saccharification pretreatment product is completed, and the step of obtaining the ammonia separation saccharification pretreatment product for releasing ammonia from the ammonia-containing saccharification pretreatment product is started. The hot water conduit 15 and the hot water conduit 15b are connected by the fifth switching valve 62 and the sixth switching valve 63. And while the process of obtaining the said ammonia separation saccharification pre-processed product is performed in the reaction container 2a, the process of supplying a substrate and ammonia water to the reaction container 2b and starting a substrate mixture is started.

  At this time, neither of the reaction vessels 2a and 2b needs to be heated with the hot water. Therefore, during this time, the hot water can be circulated through the first bypass circulation path, and the hot water heated to a temperature higher than a predetermined temperature at which the substrate mixture is heated can be stored in the hot water secondary tank 24.

  In addition, when the ammonia-containing saccharification pre-processed product is held for a predetermined time, the heat pump 19 may be stopped in order not to generate excess hot water or cold / hot water. In this case, extra energy is required to restart the heat pump 19. On the other hand, since the pretreatment device 1 shown in FIG. 3 operates and does not stop the heat pump 19 while it is held for a predetermined time, it can operate efficiently and consume less energy.

  In the reaction vessel 2a, when the step of obtaining the ammonia separation saccharification pretreatment product is completed, the ammonia separation saccharification pretreatment product is discharged and transferred to the next step to remove the residue of the substrate and wash the reaction vessel 2a itself. Is done. Further, since the seventh switching valve 64 connects the first exhaust conduit 8a and the first exhaust conduit 8b, the pretreatment can be performed in the reaction vessel 2b in exactly the same manner as the reaction vessel 2a.

  In the pretreatment apparatus 1 shown in FIG. 3, the treatment efficiency can be improved by performing the pretreatment using the reaction vessels 2a and 2b alternately as described above.

  In the pretreatment apparatus 1 shown in FIG. 3, an example is shown in which the reaction vessel 2 has two reaction vessels 2a and 2b. However, the reaction vessel 2 has three or more reaction vessels 2a, 2b, 2c, The pre-processing may be performed by sequentially using.

  DESCRIPTION OF SYMBOLS 1 ... Pretreatment apparatus, 2 ... Reaction container, 3 ... Ammonia condenser, 4 ... Ammonia absorption tower, 5 ... Ammonia tank, 15 ... Hot water conduit, 16 ... Hot water primary tank, 19 ... Two-way heat pump, 21 ... Hot water Bypass conduit, 23 ... Hot water conduit, 24 ... Hot water secondary tank, 26 ... Hot water supply conduit, 48 ... Low temperature water conduit, 49 ... Low temperature water primary tank, 52 ... Low temperature water bypass conduit, 54 ... Cold water conduit, 55 ... secondary tank for low-temperature water, 57 ... cold water supply conduit.

Claims (5)

A step of mixing a lignocellulosic biomass as a substrate with ammonia water in a batch system to obtain a substrate mixture, and heating the substrate mixture to a predetermined temperature and holding the substrate mixture at the temperature for a predetermined time, thereby lignin from the substrate. Dissociating or swelling the substrate to obtain an ammonia-containing saccharification pretreatment product, and releasing ammonia from the ammonia-containing saccharification pretreatment product to obtain an ammonia separation saccharification pretreatment product from which ammonia has been separated, and A step of cooling and condensing ammonia released from the ammonia-containing saccharification pretreatment product and dissolving it in water to obtain ammonia water, and recovering the ammonia water,
Supplying a first heat medium for heating the substrate mixture and a second heat medium for recovering the heat of condensation when condensing the ammonia and the heat of dissolution when dissolving in water to the heat pump; By heat exchange between the first heat medium and the second heat medium, the substrate mixture is heated using the heated first heat medium, and the ammonia is heated using the cooled second heat medium. In the pretreatment method of the biomass to be cooled,
A first bypass circulation path for circulating the first heat medium to the heat pump, bypassing the first heating path for circulating the first heat medium to the heat pump and the part for heating the substrate mixture; And heating the first heat medium to a temperature higher than the predetermined temperature by circulating the first heat medium to the first bypass circulation path, and storing a predetermined amount of the first heat medium heated to a temperature higher than the predetermined temperature. And heating the substrate mixture with a first heating medium heated to a temperature higher than the predetermined temperature until the substrate mixture reaches the predetermined temperature.
A second circulation path for circulating the second heat medium to the heat pump and the part for cooling the ammonia is provided in the second bypass circulation path for bypassing the part for cooling the ammonia and circulating to the heat pump; By circulating the second heat medium to the second bypass circulation path, the second heat medium is cooled to a temperature lower than the temperature at which the second heat medium is circulated to the second circulation path, and is circulated to the second circulation path. A second amount of the second heat medium cooled to a temperature lower than the temperature at the time is stored in advance, and the concentration of ammonia released from the ammonia-containing pre-saccharification product is reduced to a predetermined concentration. Before the biomass is reduced to a predetermined amount, the ammonia is cooled by the second heat medium cooled to a temperature lower than the temperature when circulating in the second circulation path. Management method.   The biomass pretreatment method according to claim 1, wherein the heat pump is a binary heat pump.   The biomass pretreatment method according to claim 1 or 2, wherein the storage of the first heat medium heated to a temperature higher than the predetermined temperature is performed during the step of obtaining the substrate mixture, Storage of the second heat medium cooled to a temperature lower than the temperature when circulating in the circulation path is performed between the step of obtaining the substrate mixture and the step of obtaining the ammonia-containing saccharification pretreatment product. To pre-process biomass. In the biomass pretreatment method according to any one of claims 1 to 3,
A plurality of reaction vessels for performing the step of obtaining the substrate mixture, the step of obtaining the ammonia-containing saccharification pre-treatment product, and the step of obtaining the ammonia separation saccharification pre-treatment product are provided. The step of obtaining the substrate mixture in at least one other reaction vessel and the step of obtaining the ammonia-containing saccharification pre-treatment product until the step of obtaining the next substrate mixture is started. And a step of obtaining the ammonia separation saccharification pretreatment product,
A biomass pretreatment method, characterized in that the first circulation path is provided for each reaction vessel, and a common first bypass circulation path is provided for each reaction vessel.   In the pretreatment method of biomass according to claim 4, performing the step of obtaining the substrate mixture in another one reaction vessel while releasing ammonia from the ammonia-containing saccharification pretreatment product obtained in one reaction vessel, A biomass pretreatment method characterized in that the first heat medium heated to a temperature higher than the predetermined temperature is stored at the same time.

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