WO2011111692A1

WO2011111692A1 - Ethanol manufacturing device and ethanol manufacturing method

Info

Publication number: WO2011111692A1
Application number: PCT/JP2011/055352
Authority: WO
Inventors: 敏春角谷; 長谷川　博; 山崎　幸一; 隆史下田; 耕三西堀
Original assignee: 株式会社雪国まいたけ
Priority date: 2010-03-08
Filing date: 2011-03-08
Publication date: 2011-09-15
Also published as: JP2011182685A; JP5606756B2

Abstract

The disclosed ethanol manufacturing device (1) is provided with a solid-liquid separation means (2), a distillation means (3), a drying means (4), and a vapor-supply means (5). The solid-liquid separation means (2) separates a fermented substance (60), which has undergone ethanol fermentation, into an ethanol-containing filtrate (61) and a filter cake (62). The distillation means (3) concentrates the ethanol-containing filtrate (61) via distillation, yielding ethanol (6). The drying means (4) dries the filter cake. The vapor-supply means (5) supplies, to the distillation means (3), an ethanol-containing vapor (63) generated by the drying performed by the drying means (4). Also disclosed is a method for manufacturing ethanol by performing a solid-liquid separation step, a drying step, and a distillation step.

Description

Ethanol production apparatus and ethanol production method

The present invention relates to an ethanol production apparatus and an ethanol production method for producing ethanol from lignocellulosic biomass.

In recent years, the regeneration of fuel from biomass has attracted attention due to the growing awareness of environmental issues. For example, lignocellulosic biomass such as woody biomass contains a large amount of cellulose, and this cellulose can be converted to ethanol by ethanol fermentation by degrading (saccharifying) to glucose. Hydrolysis with concentrated sulfuric acid has been used for saccharification of lignocellulosic biomass (see Non-Patent Documents 1 and 2).
However, although saccharification with concentrated sulfuric acid can extract glucose from lignocellulosic biomass, it is necessary to consider the corrosion of the apparatus, and it is not practical considering a large facility at the factory level. There is a problem that costs for saccharification and maintenance costs increase.

In addition to saccharification with concentrated sulfuric acid, enzymatic saccharification methods are known. That is, it is a method of obtaining glucose under mild conditions by using an enzyme cellulase that decomposes cellulose. In addition, there is a method of preventing the activity of cellulase from being inhibited by using ethanol fermentation with cellulase and yeast, and improving the ethanol conversion efficiency (see Non-Patent Document 3).

By such a method, ethanol can be produced from cellulose via glucose.
However, in lignocellulosic biomass, it is difficult to isolate cellulose because it is surrounded by lignin that is difficult to decompose. Such lignocellulosic biomass is hardly saccharified even if it is directly reacted with cellulase or the like.

On the other hand, filamentous fungi are known as organisms that can degrade lignin contained in wood. Among the filamentous fungi, white rot fungi release strong lignin degrading enzymes to degrade lignin.
White rot fungi include edible mushrooms such as shiitake mushrooms, oyster mushrooms and maitake mushrooms, which are cultivated by fungus bed cultivation using wood.
Edible mushrooms such as maitake are cultivated on a large scale in factories, and thus a large amount of waste fungus beds are produced after cultivation. And the waste microbial bed generated here is attracting attention as lignocellulosic biomass in which cellulose is present in a state where lignin is decomposed and cellulase is easily decomposed, and a method for converting to bioethanol using this has been developed. (See Patent Documents 1 and 2).

JP 2006-20603 A JP 2006-230365 A

However, it has been difficult to increase the size of the bioethanol conversion methods that have been developed so far.
That is, when producing ethanol from an ethanol fermented product at a large-scale level in a factory, the energy balance becomes important. Conventional methods have been difficult to put into practical use from the viewpoint of energy balance.

The present invention has been made in view of such problems, and an object of the present invention is to provide an ethanol production apparatus and an ethanol production method capable of obtaining ethanol from an ethanol fermentation product with an excellent energy balance.

1st invention, the solid-liquid separation means which isolate | separates the fermented material after ethanol fermentation into an ethanol containing filtrate and a filter cake,
A distillation means for concentrating ethanol in the ethanol-containing filtrate by distillation;
Drying means for drying the filter cake;
An ethanol production apparatus comprising: a steam supply unit configured to supply ethanol-containing steam generated by drying in the drying unit to the distillation unit.

The second invention is a solid-liquid separation step of separating the fermented product after ethanol fermentation into an ethanol-containing filtrate and a filter cake,
A drying step of drying the filter cake,
A method for producing ethanol, comprising: concentrating the ethanol-containing filtrate by distillation in a distillation column to obtain ethanol, and supplying the ethanol-containing vapor generated in the drying step to the distillation column. It is in.

The ethanol production apparatus of the first invention comprises at least the solid-liquid separation means, the distillation means, the drying means, and the steam supply means.
In the solid-liquid separation means, the fermented product after ethanol fermentation is separated into an ethanol-containing filtrate and a filter cake. And in the said distillation means, the ethanol in the said ethanol containing filtrate is concentrated by distillation. In this way, ethanol can be obtained from the fermented product after ethanol fermentation.

The most notable point in the present invention is the provision of the drying means and the steam supply means.
Since the drying means dries the filter cake separated in the solid-liquid separation means, during the drying, ethanol, moisture and the like remaining in the filter cake are generated as the ethanol-containing vapor. And since the ethanol manufacturing apparatus of this invention is equipped with the said vapor | steam supply means, it can supply the said ethanol-containing vapor | steam generated during drying to the said distillation means. Therefore, it is possible to recover the ethanol remaining in the filter cake and to obtain ethanol with a high yield.

Furthermore, since the steam supply means supplies ethanol as the ethanol-containing steam to the distillation means in the form of steam, the heat energy of the ethanol-containing steam can be supplied to the distillation means and used for distillation. . That is, the thermal energy used in the drying means can be transferred to the distillation means for use. Therefore, the energy balance during ethanol production can be improved.

Thus, according to the first aspect of the present invention, an ethanol production apparatus capable of obtaining ethanol from an ethanol fermentation product with an excellent energy balance can be provided.

The method for producing ethanol of the second invention includes at least the solid-liquid separation step, the drying step, and the distillation step.
In the solid-liquid separation step, the fermented product after ethanol fermentation is separated into an ethanol-containing filtrate and a filter cake. In the distillation step, the ethanol-containing filtrate is concentrated by distillation in a distillation column to obtain ethanol. In this way, ethanol can be obtained from the fermented product after ethanol fermentation.

In particular, the point to be noted in the present invention is that the drying step and the distillation step are performed.
That is, in the drying step, the filter cake separated in the solid-liquid separation step is dried. At this time, ethanol and water contained in the filter cake are generated as the ethanol-containing vapor. In the distillation step, the ethanol-containing vapor generated in the drying step is supplied into the distillation column. Therefore, ethanol remaining in the filter cake after the solid-liquid separation step can also be recovered, and ethanol can be obtained with high yield.

Furthermore, in the distillation step, as described above, the ethanol-containing vapor is supplied into the distillation column. That is, ethanol is supplied into the distillation column in a vapor state. Therefore, at least a part of the thermal energy necessary for distillation in the distillation step can be obtained from the ethanol-containing steam generated in the drying step. Therefore, the energy balance can be improved.

Thus, according to the second invention, it is possible to provide an ethanol production method capable of obtaining ethanol from an ethanol fermentation product with an excellent energy balance.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which shows the ethanol manufacturing apparatus concerning Example 1. FIG. FIG. 3 is an explanatory diagram showing solid-liquid separation means according to the first embodiment. Explanatory drawing which shows the ultrafiltration means concerning Example 1. FIG. FIG. 3 is an explanatory diagram showing distillation means according to the first embodiment. FIG. 3 is an explanatory diagram illustrating a drying unit and a steam supply unit according to the first embodiment. Explanatory drawing which shows the drying means and vapor | steam supply means concerning Example 2. FIG.

In the ethanol production apparatus and the ethanol production method of the present invention, a fermented product after ethanol fermentation is used.
The fermented product is preferably obtained by subjecting a mixture of lignocellulosic biomass, water and cellulolytic enzyme to ethanol fermentation with a microorganism.
In this case, lignocellulosic biomass such as woody biomass can be effectively used.

The lignocellulosic biomass is preferably a fungal bed in which filamentous fungi are being cultured and / or a waste fungus bed of filamentous fungi.
Since filamentous fungi can degrade lignin, in this case, the waste fungus bed contains cellulose in a state where it is easily degraded by enzymes. Therefore, ethanol fermentation can easily proceed, and the yield of ethanol from lignocellulosic biomass can be improved.

The filamentous fungus is preferably a white rot fungus.
In this case, the strong lignin resolving power of white rot fungi can be used, and the waste fungus bed contains cellulose in a state where it is more easily decomposed.
Therefore, the yield of ethanol from the lignocellulosic biomass can be further improved.

Among the white rot fungi, edible mushroom maitake, eringi, beech shimeji mushroom, shiitake mushroom or waste sorghum bed is preferred. Since these are cultivated on a large scale with fungus beds containing sawdust, a large amount of waste fungus beds containing cellulose can be obtained at a low cost while being easily decomposed.
Particularly preferably, the white rot fungus is maitake.

As the cellulose-degrading enzyme, those capable of saccharifying cellulose or hemicellulose can be used. For example, cellulase, hemicellulase, or a mixture of both can be used. As the cellulolytic enzyme, a purified product from a culture solution in which filamentous fungi are cultured, the culture solution itself, or a commercially available product can be used.

Moreover, as the microorganism, a microorganism capable of ethanol fermentation can be selected.
Specifically, for example, Saccharomyces cereviciae, Pichia stipitis, Shizosaccharomyces pombe, or the like can be used. Commercial baker's yeast can also be used.
As a culture solution in ethanol fermentation, a medium optimal for microorganisms can be adopted.

The ethanol production apparatus includes at least the solid-liquid separation unit, the distillation unit, the drying unit, and the vapor supply unit.
The said solid-liquid separation means is comprised so that the fermented material after ethanol fermentation may be isolate | separated into an ethanol containing filtrate and a filter cake, for example, can be comprised with a filter press machine. In a small-scale apparatus, a centrifugal separator can be used.
A filter press is preferable.
In this case, since pressure filtration can be performed, solid-liquid separation can be sufficiently performed even if the specific gravity difference between the solid and the liquid is small.

Next, the ethanol production apparatus preferably includes an ultrafiltration means for recovering the cellulolytic enzyme by ultrafiltration of the ethanol-containing filtrate.
The fermented product is separated into an ethanol-containing filtrate and a filter cake by the solid-liquid separation means. When cellulose-degrading enzyme is used for ethanol fermentation, cellulose-degrading enzyme is contained in the ethanol-containing filtrate.
When the ultrafiltration means is provided as described above, the expensive cellulose-degrading enzyme can be recovered from the ethanol-containing filtrate and can be reused.
The ultrafiltration means can be composed of a commercially available ultrafiltration membrane (UF membrane) or the like.

Next, the distillation means is configured to concentrate ethanol in the ethanol-containing filtrate by distillation.
The distillation means can be constituted by a distillation column for performing rectification, a reboiler for cooking steam, a condenser for steam condensation, and the like. As the distillation column, a plate column provided with a plurality of plates inside, or a packed column filled with a packing to be brought into gas-liquid contact can be adopted.

The drying means is for drying the filter cake and can be constituted by a commercially available dryer or the like.
There are various types and types of dryers. For example, a dryer that is heated via a mechanical heat transfer surface can be employed. The present invention is not a drying method using a non-condensable carrier gas that makes it difficult to recover ethanol in a downstream process, and has a plurality of paddle shafts so that adhesion does not grow due to a self-cleaning effect. In addition, it is preferable to employ a dryer that has a structure through which the heating medium passes and has a heat transfer area that is as large as possible compared to the capacity of the can body including the heating jacket outside the can body.

Preferably, the drying means superheats the ethanol-containing steam generated from the filter cake during drying to a superheated steam state, and contacts the ethanol-containing steam in the superheated steam state with the filter cake. It is preferable to have a configuration. That is, it is preferable to employ a superheated steam dryer as the drying means.
In this case, it is possible to prevent the filter cake from adhering to the heat transfer surface, which may occur when a dryer using a mechanical heat transfer surface is used. In this case, the ethanol-containing steam generated during drying is recycled and heated to superheated steam for drying, so that the heat balance (energy balance) can be further improved.

In the superheated steam dryer, condensable steam is employed instead of non-condensable like air, and superheating is performed so that steam does not condense in the drying process. In the superheated steam dryer, it is preferable to blow superheated steam from the entire lower surface of the dryer toward the upper portion of the dryer. In this case, the filter cake can be loosened by the superheated steam while the superheated steam is brought into direct contact with the filter cake. Therefore, the whole filter cake and the superheated steam can be brought into uniform contact with the filter cake (wet powder) flowing. Therefore, the filter cake can be dried by efficiently conducting heat transfer.

Moreover, it is preferable that the said ethanol manufacturing apparatus is equipped with the combustion means which burns the residue obtained by drying the said filter cake with the said drying means.
In this case, combustion energy can be extracted from the residue, and the residue can be used as fuel. The combustion energy generated here can be used for drying means, distillation means and the like. Therefore, the energy balance of the said ethanol manufacturing apparatus can be improved more.

Next, the ethanol manufacturing apparatus includes a steam supply unit that supplies the ethanol-containing steam generated by drying in the drying unit to the distillation unit.
The steam supply means can be constituted by a pipe or the like connecting the drying means and the distillation means.

Moreover, it is preferable that the said ethanol manufacturing apparatus is equipped with the concentration means which concentrates the ethanol concentrated by the said distillation means.
In this case, ethanol with higher purity can be obtained.
As the concentration means, a known concentration / dehydration technique such as a membrane separation method such as a pervaporation (PV) method or a vapor permeation (VP) method, or a PSA (pressure swing adsorption) using an adsorbent is adopted. Can do.
Preferably, the pervaporation method is good, and the concentration means can be constituted by, for example, a commercially available pervaporation (PV) membrane.
In this case, it becomes possible to obtain ethanol having a high purity of, for example, 99.5 wt% or more, and ethanol that can be used as an alcohol fuel can be manufactured.

Next, in the method for producing ethanol of the present invention, as described above, the solid-liquid separation step, the drying step, and the distillation step are performed.
In the solid-liquid separation step, the fermented product after ethanol fermentation is separated into an ethanol-containing filtrate and a filter cake.
In the solid-liquid separation step, it is preferable to perform solid-liquid separation until the liquid content of the filter cake is 75 wt% or less.
When the liquid content of the filter cake exceeds 75 wt%, solid-liquid separation is insufficient and the final ethanol yield may be reduced. Moreover, the drying time in the below-mentioned drying process will become long, and there exists a possibility that an energy balance may worsen. Furthermore, when the cellulose-degrading enzyme is used for the ethanol fermentation and the cellulose-degrading enzyme is recovered by performing the ultrafiltration step described later, the recovery rate of the cellulose-degrading enzyme may be reduced.
In addition, it is difficult to reduce the liquid content to less than 60% by solid-liquid separation, even if solid-liquid separation means such as a filter press having a pressing mechanism of 3 to 5 MPaG is used due to the characteristics of the fermented product. Cost may increase. From this viewpoint, the liquid content of the filter cake in the solid-liquid separation step is preferably 60 wt% or more. More preferably, it is 65 wt% or more. Note that the liquid content of the filter cake can be made 75 to 65 wt% by a solid-liquid separation means having a pressing mechanism of 0.3 to 3 MPaG.
For example, when solid-liquid separation is performed by a filter press, the liquid content of the filter cake can be controlled by adjusting the size of the press pressure, the pore diameter of the filter, and the like.

It is preferable to perform an ultrafiltration step of recovering the cellulolytic enzyme by ultrafiltration of the ethanol-containing filtrate between the solid-liquid separation step and the distillation step.
In this case, the expensive cellulose-degrading enzyme used for ethanol fermentation can be recovered and reused.
The ultrafiltration step can be performed using, for example, an ultrafiltration membrane (UF membrane).

In the drying step, the filter cake is dried.
As described above, the drying step can be performed using a commercially available dryer such as a dryer that is heated via a mechanical heat transfer surface or a superheated steam dryer.

In the drying step, it is preferable that the ethanol-containing steam generated from the filter cake during drying is heated to a superheated steam state, and the ethanol-containing steam in the superheated steam state is brought into contact with the filter cake.
In this case, it is possible to prevent the filter cake from adhering to the heat transfer surface, which may occur when a dryer using a mechanical heat transfer surface is used. In this case, the ethanol-containing steam generated during drying is recycled and heated to superheated steam for drying, so that the heat balance (energy balance) can be further improved.

In the drying step, drying is preferably performed until the liquid content of the filter cake reaches 40 wt% to 60 wt%.
When the liquid content of the filter cake exceeds 60 wt%, ethanol remains in the filter cake and the ethanol yield may be reduced. Furthermore, when the filter cake is burned to obtain combustion energy, the handleability of the filter cake is deteriorated and the combustion efficiency may be deteriorated. On the other hand, if it is less than 40 wt%, the concentration of the recovered ethanol may decrease. Moreover, there is a possibility that the energy loss becomes large and the energy balance is deteriorated.
According to a batch-type evaporation test, the ethanol concentration in the ethanol-containing steam decreases in a quadratic curve, and when the liquid content of the filter cake reaches 47-42 wt%, the ethanol is almost completely removed from the filter cake. It can be recovered. Therefore, in the drying step, it is more preferable to perform the drying until the liquid content of the filter cake becomes 40 wt% to 50 wt%.
The liquid content of the filter cake after the drying step can be controlled by adjusting drying conditions such as drying temperature and drying time.

Moreover, it is preferable to provide the combustion process which burns the residue obtained by drying the said filter cake in the said drying process, and obtains combustion energy.
In this case, the residue can be used as a fuel, for example, as a heat energy source in a drying process or the like. Therefore, the energy balance of the said ethanol manufacturing apparatus can be improved more.

Moreover, the concentration process which concentrates the ethanol concentrated in the said distillation process can be performed. In this case, ethanol with higher purity can be obtained.
In the concentration step, a known concentration / dehydration technique such as a membrane separation method such as a pervaporation (PV) method or a vapor permeation (VP) method or a PSA (pressure swing adsorption) using an adsorbent should be employed. Can do.
The pervaporation method is preferable. In this case, it becomes possible to obtain ethanol having a high purity of, for example, 99.5 wt% or more, and ethanol that can be used as an alcohol fuel can be manufactured. The concentration step by the pervaporation method can be performed using, for example, a commercially available pervaporation (PV) membrane.

Example 1
Next, an ethanol production apparatus according to an embodiment of the present invention will be described.
As shown in FIG. 1, the ethanol production apparatus 1 of this example includes a solid-liquid separation unit 2, a distillation unit 3, a drying unit 4, and a steam supply unit 5.
The solid-liquid separation means 2 separates the fermented product 60 after ethanol fermentation into an ethanol-containing filtrate 61 and a filter cake 62. The distillation means 3 concentrates ethanol in the ethanol-containing filtrate 61 by distillation. This gives ethanol 6.
The drying means 4 dries the filter cake 62. The steam supply unit 5 supplies the ethanol-containing steam 63 generated by the drying in the drying unit 4 to the distillation unit 3.

The ethanol production apparatus 1 of this example further includes an ultrafiltration means 11 and a concentration means 12.
The ultrafiltration means 11 recovers the cellulose degrading enzyme 64 from the ethanol-containing filtrate 61 by ultrafiltration of the ethanol-containing filtrate 61. The concentration means 12 further concentrates the ethanol 6 concentrated by the distillation means 3 by a pervaporation method.

If the ethanol manufacturing apparatus 1 of this example is used, a solid-liquid separation process, a drying process, and a distillation process can be performed.
That is, in the solid-liquid separation step, the fermented product 60 after ethanol fermentation is separated into an ethanol-containing filtrate 61 and a filter cake 62.
In the drying step, the filter cake 62 is dried, and in the distillation step, the ethanol-containing filtrate 61 is concentrated by distillation in the distillation column 3 to obtain ethanol 6, and the ethanol content generated in the distillation column 3 in the drying step is contained. Steam 63 is supplied.

Moreover, in the ethanol apparatus 1 of this example, an ultrafiltration process, a concentration process, and a combustion process can be performed.
In the ultrafiltration step, the cellulolytic enzyme 64 is recovered by ultrafiltration of the ethanol-containing filtrate 61. In the concentration step, the ethanol 6 concentrated in the distillation step is concentrated by a pervaporation method. In the combustion process, the residue 65 obtained by drying the filter cake 62 in the drying process is burned to obtain combustion energy.

Hereinafter, the ethanol production apparatus 1 of this example will be described in detail with reference to FIGS.
FIG. 1 is a block diagram including raw materials and products of the ethanol production apparatus of this example, and FIGS. 2 to 5 are explanatory diagrams showing the ethanol production apparatus divided into four parts. .
First, FIG. 2 shows an explanatory diagram showing the peripheral configuration of the solid-liquid separation means 2 of the ethanol production apparatus 1. As shown in the figure, the ethanol production apparatus of this example includes a fermentation slurry tank 10 that stores a slurry-like fermentation product 60 upstream of the solid-liquid separation means 2.

The fermentation slurry tank 10 stores a fermented product 60 obtained by subjecting a mixture of lignocellulosic biomass, water, and cellulose-degrading enzyme (cellulase) to ethanol fermentation with a microorganism (Saccharomyces cerevisiae). As lignocellulosic biomass, the waste microbial bed of maitake, which is a white rot fungus, is employed.
The fermentation slurry tank 10 stores a slurry in which a solid component such as lignin, unsaccharified cellulose, and hemicellulose and a liquid containing ethanol are mixed.

A filter press as the solid-liquid separation means 2 is provided downstream of the fermentation slurry tank 10. The filter press 2 has a structure in which a plurality of filter frames 21 and filter cloths 22 are arranged in parallel. In the filter press 2, depending on the combination of the size and quantity of the filter frame 21 and the filter cloth 22, small to large scale (number of filter chambers: several to several hundred rooms, filtration area: several m ² to several hundred m ² ) Can be selected.

The fermentation slurry tank 10 and the solid-liquid separation means 2 are connected by a pipe 100 through which the fermented product 60 passes, and in the middle of the pipe 100, a slurry-like fermented product 60 stored in the fermentation slurry tank 10. A driving pump 25 for press-fitting the liquid into the solid-liquid separation means 2 is provided. Moreover, the compressed air tank 26 which stores the compressed air 600 used in order to squeeze a fermented material after the injection into the solid-liquid separation means 2 is provided, and compressed air passes between the compression tank 26 and the solid-liquid separation means 2. They are connected by a pipe 101.

Further, downstream of the solid-liquid separation means 2, a filtrate tank 23 for storing the separated ethanol-containing filtrate and a belt conveyor 24 for carrying the separated filter cake to the drying means are provided. The filtrate tank 23 is connected to the solid-liquid separation means 2 by a pipe 102 through which the ethanol-containing filtrate passes.

Next, as shown in FIG. 3, the ethanol production apparatus of this example includes an ultrafiltration means 11. The ultrafiltration means 11 includes a circulation tank 110, a filtrate pump 111, and an ultrafiltration membrane (UF membrane) 112.
A filtrate pump 113 that supplies the ethanol-containing filtrate in the filtrate tank 23 to the circulation tank 110 is provided on the upstream side of the ultrafiltration means 11. The filtrate tank 23 and the circulation tank 110 are connected by a pipe 103 through which an ethanol-containing filtrate passes, and a strainer 114 of 50 to 80 mesh (aperture 0.3 to 0.17 mm) is disposed in the middle of the pipe 103. ing.

In the ultrafiltration means 11, the circulation tank 110 and the ultrafiltration membrane 112 are connected to the pipe 104 through which the ethanol-containing filtrate sent from the circulation tank 110 to the ultrafiltration membrane 112 passes, and from the ultrafiltration membrane 112 to the circulation tank 110. It is connected by a pipe 105 through which the returning ethanol-containing filtrate passes. That is, the ethanol-containing filtrate can be circulated between the circulation tank 110 and the ultrafiltration membrane 112. As the ultrafiltration membrane 112, one having a molecular weight fraction of 20,000 to 30,000 is adopted, and the cellulose-degrading enzyme is concentrated and recovered in the ultrafiltration membrane 112.
The ethanol-containing filtrate from which the cellulolytic enzyme is recovered is sent to the filtrate tank 30 through the pipe 106.

Next, as shown in FIG. 4, the ethanol production apparatus of this example includes a distillation means 3.
The distillation means 3 includes a distillation column 31 for performing rectification, a reboiler 311 for cooking steam, and a condenser 312 for condensing the steam, which is provided on the top of the distillation column 31. .
As the distillation column 31, a tray column provided with a plurality of shelves 310 inside, or a packed column filled with a packing to be brought into gas-liquid contact can be adopted. An example employing a tower will be described (see FIG. 4). In this example, the distillation column 31 has 20 shelf stages 310 inside, and constitutes a total of 22 theoretical stages together with the condenser 312 and the reboiler 311.

The ethanol-containing filtrate stored in the filtrate tank 30 is sent to the distillation means 3 through the pipe 107 by the distillation feed pump 32. A flow rate control (FC) 33 is installed on the discharge side of the distillation feed pump 32, and the ethanol-containing filtrate is supplied to the distillation means 3 at a predetermined flow rate. Also, at the bottom of the distillation means 3, a distillation tower bottom pump 351 for discharging the liquid having a boiling point accumulated at the bottom of the distillation tower to the outside from the discharge pipe 354, and a level control (LC) 352 for controlling the discharge amount are discharged. And a recovery heat exchanger 353 for recovering heat from the liquid. When the ethanol-containing filtrate in the pipe 107 is supplied into the distillation means 3, it is heated by heat exchange in the recovery heat exchanger 353 and then supplied into the distillation means 3.

Further, the distillation means 3 introduces a filtrate inlet 341 into which an ethanol-containing filtrate sent from the filtrate tank 30 through the pipe 107 is introduced, and a steam introduction into which an ethanol-containing vapor sent from a dryer described later is introduced. A mouth 342 is provided. In the distillation means 3 of this example, the steam inlet 342 is provided on the lower stage side than the filtrate inlet 341. Specifically, in the distillation means 3 of this example, if the uppermost stage is the first stage and the lowermost stage is the 22nd stage among the total number of 22 theoretical stages described above, the filtrate inlet 341 is the seventh stage. The steam inlet 342 is provided at the position of the eleventh stage. In the distillation means 3 of this example, the uppermost stage (first stage) is the condenser 312 and the lowermost stage (22nd stage) is the reboiler 311.

The positions of the filtrate inlet 341 and the steam inlet 342 can be determined by a simulation based on the ethanol concentration in the ethanol-containing filtrate and ethanol-containing steam and the ethanol concentration by the distillation means 3. In this example, the positions of the filtrate inlet 341 and the steam inlet 342 are determined in the range of ethanol concentration 2 to 3 wt% in the ethanol-containing filtrate and ethanol concentration 3 to 5 wt% in the ethanol-containing steam.

Further, in this example, the concentration means 12 made of a pervaporation membrane (PV membrane) is provided downstream of the distillation means 3, and the ethanol concentrated in the distillation means 3 is further concentrated in the concentration means 12.

As shown in FIG. 5, the ethanol production apparatus of this example includes a drying means 4.
In this example, the drying means 4 may be, for example, a multi-axis dryer manufactured by Kurimoto Steel Works or Nara Machinery Co., Ltd. FIG. 5 shows the dryer 4 having two

paddle shafts

41 and 42 that can rotate in the drying can 40, and a plurality of

heat transfer blades

415 and 425 are formed around the

paddle shafts

41 and 42, respectively. Has been. Moreover, the periphery of the drying can 40 is covered with a jacket (not shown), and heat transfer can be further promoted.
A screw feeder 43 having a screw 431 inside is provided at the inlet of the dryer. The filter cake separated by the solid-liquid separation means 2 is carried by the belt conveyor 24 (see FIG. 2), and is put into the drying means 4 from the screw feeder 43 shown in FIG.

At the bottom of the drying means 4 is provided a rotary valve 44 for extracting the residue after drying. A vertical conveyor (not shown) is provided downstream of the rotary valve 44, and the residue is stored in a hopper (not shown) by this vertical conveyor. After that, it is burned by a boiler (not shown) as necessary, and combustion energy can be obtained. This combustion energy can be used as the energy of the drying means 4.

Further, as shown in FIG. 5, a steam supply means 5 comprising a pipe connecting the drying means 4 and the distillation means 3 (see FIG. 4) is provided at the upper part of the drying means 4, from the filter cake at the time of drying. The generated ethanol-containing steam is sent from the steam supply means 5 to the distillation means 3 (see FIG. 4).

Next, the flow of raw materials and products in the ethanol production apparatus of this example will be described.
In the ethanol production apparatus, first, as shown in FIG. 2, the fermented product 60 stored in the fermentation slurry tank 10 is pressed into the solid-liquid separation means 2 including a filter press through the pipe 100 by the driving pump 25. Further, the compressed air 600 in the compression tank 26 is introduced into the solid-liquid separation means 2 through the pipe 101. The fermented product 60 is compressed in the solid-liquid separation means 2 by the compressed air 600 and separated into an ethanol-containing filtrate and a filter cake (solid-liquid separation step). In this example, squeezing is performed until the liquid content of the filter cake reaches 70 wt%.
The separated ethanol-containing filtrate is stored in the filtrate tank 23 through the pipe 102, and the filter cake is conveyed to the drying means 4 (see FIG. 5) by the belt conveyor 24.

As shown in FIG. 3, the ethanol-containing filtrate stored in the filtrate tank 23 is once sent to the circulation tank 110 through the pipe 103 by the filtrate pump 113. At this time, the particles (solid matter) contained in the ethanol-containing filtrate are removed by the strainer 114 disposed in the middle of the pipe 103. Thereby, blockage in the downstream ultrafiltration membrane can be prevented.
The ethanol-containing filtrate sent into the circulation tank 110 passes through the ultrafiltration membrane 112 through the pipe 104 and returns to the circulation tank 110 through the pipe 105 by the filtrate pump 111. At this time, in the ultrafiltration membrane 112, the cellulose-degrading enzyme contained in the ethanol-containing filtrate is concentrated, and the concentrate (cellulose-degrading enzyme) 64 is recovered (ultrafiltration step). Water, ethanol, and the like in the ethanol-containing filtrate pass through the ultrafiltration membrane 112 and are sent to the filtrate tank 30 through the pipe 106.

On the other hand, the filter cake separated in the solid-liquid separation means 2 as described above is conveyed to the drying means by the belt conveyor 24 (see FIGS. 2 and 5). As shown in FIG. 5, the filter cake is introduced into the drying means 4 by a predetermined amount by a screw 431 of the screw feeder 43.
In the drying means 4, the

heat transfer blades

415 and 425 are rotated by rotating the two

paddle shafts

41 and 42, and the filter cake is heated and dried by contact with the heated heat transfer blades (drying step). ). In this example, the residue is dried to a liquid content of 45%. The ethanol-containing steam generated at the time of drying is sent to the distillation means 3 shown in FIG. 4 through the steam supply means 5 composed of a pipe connected to the upper part of the drying means 4. And it is supplied into the distillation means 3 from the steam inlet 342.
Further, as shown in FIG. 5, the residue remaining in the drying means 4 after drying is discharged from the rotary valve 44 and stored in a hopper (not shown) by a vertical conveyor. The residue stored in the hopper is burned as necessary by combustion means (not shown) such as a boiler and used as combustion energy.

Further, the ethanol-containing filtrate stored in the filtrate tank 30 as described above is sent to the distillation means 3 through the pipe 107 by the distillation feed pump 32 (see FIG. 4). At this time, the ethanol-containing filtrate is supplied from the filtrate inlet 341 to the distillation means 3 at a predetermined flow rate by a flow rate control (FC) 33. Further, as described above, the ethanol-containing steam sent through the steam supply means 5 is supplied to the distillation means 3 from the steam inlet 342.

When the ethanol-containing filtrate in the pipe 107 is supplied into the distillation means 3, the high-temperature liquid in the distillation means 3 is discharged by the distillation tower bottom pump 351 by a predetermined amount controlled by the level control 352. It is discharged from the pipe 354 to the outside. The hot liquid in the discharge pipe 354 is subjected to heat exchange with the ethanol-containing filtrate supplied to the distillation means 3 through the pipe 107 in the recovery heat exchanger 353 provided in the middle of the discharge pipe 354. It is discharged outside. That is, the ethanol-containing filtrate supplied to the distillation means 3 through the pipe 107 is heated by heat exchange with the high-temperature liquid discharged through the discharge pipe 354 in the recovery heat exchanger 353 and then the distillation means 3. Supplied in. On the other hand, the liquid discharged through the discharge pipe 354 is cooled to near the temperature of the ethanol-containing filtrate before heat exchange by heat exchange with the ethanol-containing filtrate in the pipe 107 and then discharged.

In the distillation means 3, the ethanol-containing filtrate and ethanol-containing steam introduced into the distillation tower are concentrated by distillation (distillation step). In the distillation means 3, the steam boiled by the reboiler 311 is condensed by the condenser 312, and a part thereof is extracted from the top of the column while refluxing to obtain ethanol concentrated to a purity of 90 wt%. By controlling the temperature of a specific platen, the concentration at the top of the column can be stabilized.

The ethanol concentrated in the distillation means 3 is sent to the concentration means 12 through the pipe 108. And in the concentration means 12, ethanol is further concentrated (concentration process), and ethanol 6 having a purity of 99.5 wt% or more can be obtained.

The ethanol production apparatus 1 of this example includes at least the solid-liquid separation means 2, the distillation means 3, the drying means 4, and the vapor supply means 5 (see FIGS. 1 to 5), as described above. A solid-liquid separation process, a drying process, and a distillation process can be realized.

As shown in FIG. 1, the most notable point in the ethanol production apparatus 1 of the present example is that the drying means 4 and the steam supply means 5 are provided.
At the time of drying by the drying means 4, ethanol and moisture remaining in the filter cake 62 are generated as the ethanol-containing vapor 63. And since the ethanol manufacturing apparatus 1 is equipped with the vapor | steam supply means 5, it can supply the ethanol containing vapor | steam 63 which generate | occur | produced during drying to the distillation means 3. FIG. Therefore, not only the ethanol-containing filtrate 61 but also the ethanol-containing steam 63 is supplied into the distillation means 3. Therefore, in the ethanol production apparatus 1 of this example, ethanol can be recovered from both the ethanol-containing filtrate 61 and the ethanol-containing steam 63, and ethanol can be obtained with high yield.

Furthermore, since ethanol is supplied from the drying means 4 to the distillation means 3 in the state of steam (ethanol-containing steam 63), the heat energy of the ethanol-containing steam 63 can be used for distillation in the distillation means 3. Therefore, the heat energy used in the drying means 4 can be transferred to the distillation means 3 as steam and reused, and the energy balance can be improved.

Further, in this example, a fermented product 60 obtained by subjecting a mixture of maitake mushroom beds, water, and a cellulolytic enzyme to ethanol fermentation with microorganisms is used. In the waste maitake mushroom bed, cellulose is contained in a state in which it is easily decomposed by enzymes, and therefore, in the fermented product 60, the cellulose is sufficiently decomposed. Therefore, ethanol 6 can be obtained with high yield.

Moreover, in this example, the solid-liquid separation means 2 is comprised by the filter press machine. Therefore, pressure filtration can be performed, and solid-liquid separation can be sufficiently performed even if the specific gravity difference between the solid and the liquid is small.
The ethanol production apparatus 1 also includes an ultrafiltration means 11 that recovers the cellulolytic enzyme 64 by ultrafiltration of the ethanol-containing filtrate 61. Therefore, the expensive cellulose-degrading enzyme 64 can be recovered from the ethanol-containing filtrate 61 and can be reused.

Moreover, the ethanol production apparatus 1 of this example includes combustion means (not shown) for burning the residue 65 obtained by drying the filter cake 62 by the drying means 4. Therefore, the residue 65 can be used as fuel, and the energy balance of the ethanol production apparatus 1 can be further improved.

Further, the ethanol production apparatus 1 is provided with a concentration means 12 for further concentrating the ethanol concentrated by the distillation means 3 by the pervaporation method. Therefore, it becomes possible to obtain ethanol having a high purity of, for example, 99.5 wt% or more, and ethanol 6 that can be applied as an alcohol fuel can be manufactured.

Moreover, in the solid-liquid separation means 2 of this example, solid-liquid separation is performed until the liquid content of the filter cake reaches about 70 wt%.
Therefore, it can prevent that the drying time in the drying means 4 becomes long and an energy balance deteriorates. In addition, the cellulolytic enzyme can be sufficiently recovered in the ultrafiltration means 11. Furthermore, ethanol can be obtained in a sufficiently high yield.
Solid-liquid separation until the liquid content of the filter cake reaches about 70 wt% can be easily realized using the solid-liquid separation means 2 by pressing at 0.5 MPaG or less.

Moreover, in the drying means 4, it dries until the liquid content of the filter cake 62 becomes about 45 wt%.
Therefore, ethanol can be sufficiently recovered as the ethanol-containing vapor, and when the filter cake 62 is burned in the combustion means, the handleability of the filter cake is improved, and the filter cake 62 is made to have a relatively good combustion efficiency. Can be burned.

Thus, according to this example, it is possible to provide an ethanol production apparatus and an ethanol production method capable of obtaining ethanol from an ethanol fermentation product with an excellent energy balance.

(Example 2)
In the first embodiment, a dryer that heats through a mechanical heat transfer surface is used as the drying means. However, in this example, a superheated steam dryer is used.
The drying means of this example is also for drying the filter cake separated by the solid-liquid separation means 2 (see FIG. 2), as in the first embodiment.

As shown in FIG. 6, the drying means 7 in this example includes a drying pipe 70, a superheater 75, and a circulation pipe 700 that circulates ethanol-containing steam generated in the drying can 70 between the drying can 70 and the superheater 75.
The drying can 70 includes a rotatable paddle shaft 71 and a plurality of stirring blades 715 provided around the paddle shaft.

Further, a screw feeder 73 having a screw 731 inside is provided at the inlet of the filter cake into the drying can 70, as in the dryer of the first embodiment. The filter cake separated by the solid-liquid separation means 2 is carried by the belt conveyor 24 (see FIG. 2), and is put into the drying can 70 from the screw feeder 73 shown in FIG.

Also, at the bottom of the drying can 70, as with the dryer of the first embodiment, a rotary valve 76 for extracting the residue after drying is provided. A vertical conveyor (not shown) is provided downstream of the rotary valve 76 as in the first embodiment, and the residue is stored in a hopper (not shown) by this vertical conveyor. After that, it is burned by a boiler (not shown) as necessary, and combustion energy can be obtained. This combustion energy can be used as the energy of the drying means 7, for example.

Further, a bag filter 74 for removing fine powder is provided on the upper portion of the drying can 70, and further, a steam supply means 5 comprising a pipe extending from the bag filter 74 to the distillation means 3 (see FIG. 4) is provided. Yes. The steam supply means 5 connects the drying can 70 and the distillation means 3, and specifically, is connected to the steam inlet 342 of the distillation means 3 as in the first embodiment (see FIG. 4).
Further, the drying means 7 is provided with a circulation pipe 700 composed of a pipe connecting the bag filter 74 and the superheater 75. The circulation pipe 700 supplies a part of the ethanol-containing steam generated from the filter cake during drying to the superheater 75.

Further, as the superheater 75, a commercially available heat exchanger can be used, and as the heating medium, for example, steam obtained by burning the residue with an OG boiler can be used. The superheater 75 indirectly heats the ethanol-containing steam sent to the superheater 75 through the circulation pipe 700 to a superheated state exceeding 100 ° C. to generate superheated steam. The drying means 7 includes a hot air circulation blower 77 that introduces the superheated steam generated by the superheater 75 into the drying can 70. A plurality of superheated steam inlets are provided at the bottom of the drying can 70, and the superheated steam is introduced upward from the bottom of the drying can 70.

Hereinafter, the operation of the drying means 7 in this example will be described.
Similar to the first embodiment, the filter cake separated in the solid-liquid separation means 2 is conveyed to the drying means 7 by the belt conveyor 24 (see FIGS. 2 and 6). As shown in FIG. 6, the filter cake is introduced into the drying can 70 by a predetermined amount by the screw 731 of the screw feeder 73.
In the drying can 70, when the paddle shaft 71 rotates, the stirring blade 715 rotates, and ethanol-containing vapor is generated from the filter cake by drying while the filter cake is stirred. A part of the ethanol-containing steam is sent to the superheater 75 through the circulation pipe 700.

In the superheater 75, the ethanol-containing steam is heated to a superheated state. The ethanol-containing steam in the superheated steam (superheated steam) state is introduced into the drying can 70 from the inlet at the bottom of the drying can 70 by the hot air circulation blower 77.
By contact with superheated steam, the filter cake is heated and dried to generate ethanol-containing steam again. A part of the ethanol-containing steam generated here is sent from the steam supply means 5 to the distillation means 3 as in the first embodiment (see FIG. 4). Further, part of the ethanol-containing vapor is sent again to the superheater 75 through the circulation pipe 700 and is introduced into the drying can 70 as superheated vapor.
In this example, the residue is dried to a liquid content of 45%.

In this example, in order to evaporate an amount commensurate with the amount of water and ethanol supplied and extract it to the distillation means 3 (see FIG. 4), the pressure in the system is controlled to be constant and the outlet temperature is set to the dew point. The amount of steam 69 supplied to the superheater 75 is controlled so that it does not become. In order to remove fine powder, the steam is returned to the superheater 75 again through the bag filter 74, heated until it becomes superheated steam, and supplied to the drying can 70. The superheated steam is supplied by the hot air circulation blower 77 from the bottom of the drying can 70 into the drying can 70 in an upward flow.

Further, as shown in FIG. 6, the residue remaining in the drying means 7 after drying is discharged from the rotary valve 44 as in the first embodiment, and the residue is stored in a hopper (not shown) by the vertical conveyor. The residue stored in the hopper is burned as necessary by combustion means (not shown) such as a boiler and used as combustion energy.
In the ethanol production apparatus of the present example, the configuration other than the drying means 7 can be the same as that of the first embodiment.

In this example, a superheated steam dryer is employed as the drying means 7. Specifically, as described above, a direct drying method using superheated steam using ethanol-containing water contained in the filter cake itself is adopted.
Therefore, it is possible to efficiently transfer heat to dry the filter cake, and to further improve the energy balance.

Generally, when a dryer using a mechanical heat transfer surface is used, strong deposits are observed on the entire paddle shaft. In Example 1, since the biaxial dryer is used, there is almost no growth of deposits, but thin deposits adhere firmly to the entire paddle shaft. Therefore, the heat transfer efficiency can be reduced as compared with the case where there is no deposit. On the other hand, when a superheated steam dryer is used as in this example, the filter cake can be heated and dried with superheated steam, so that it is possible to efficiently dry without generating any deposits.

Further, in this example, superheated steam is blown from the entire bottom of the drying can 70 toward the top (see FIG. 6). Therefore, the filter cake can be loosened by the superheated steam while the superheated steam is brought into direct contact with the filter cake. Therefore, the whole filter cake and superheated steam can be made to contact uniformly, making a filter cake (wet powder) flow. Therefore, the filter cake can be dried by conducting heat transfer more efficiently.

Moreover, in the drying means 7 of this example, ethanol contained in the filter cake is circulated between the drying can 70 and the superheater 75 using ethanol-containing steam. The steam returning from the drying can 70 to the superheater 75 is in a saturated state and is heated in the superheater 75 to be in a superheated (superheated) state and supplied into the drying can 70.
The filter cake introduced into the drying can 70 by the screw feeder 73 is separated into the ethanol-containing vapor and the drying residue and goes out of the system, so that the balance of the substance is achieved.

The amount of heat that the ethanol-containing vapor takes out of the system (distillation means 3) is given by the superheater 75. The saturated steam-containing ethanol-containing steam that is circulated and supplied to the superheater 75 obtains heat from the superheater 75, becomes superheated, and is supplied into the drying can 70. As a heat source in the superheater 75, a part of heat generated by burning the dry residue can be changed to steam or directly used as it is.

The amount of ethanol-containing steam that passes through the circulation pipe 700 (circulation steam flow rate) inevitably increases in order to cover the amount of heat for drying the filter cake by only the sensible heat of the ethanol-containing steam (the amount of heat of the superheat). . This is effective for loosening the filter cake in the drying can 70 and making sufficient contact with the filter cake.

Claims

Solid-liquid separation means for separating the fermented product after ethanol fermentation into an ethanol-containing filtrate and a filter cake,
A distillation means for concentrating ethanol in the ethanol-containing filtrate by distillation;
Drying means for drying the filter cake;
An ethanol production apparatus comprising: a steam supply unit configured to supply ethanol-containing steam generated by drying in the drying unit to the distillation unit.
2. The ethanol production apparatus according to claim 1, wherein the fermented product is obtained by subjecting a mixture of lignocellulosic biomass, water, and cellulose-degrading enzyme to ethanol fermentation with a microorganism.
3. The ethanol production apparatus according to claim 2, wherein the lignocellulosic biomass is a fungal bed in which filamentous fungi are being cultured and / or a waste fungus bed of filamentous fungi.
4. The ethanol production apparatus according to claim 3, wherein the filamentous fungus is a white rot fungus.
5. The ethanol production apparatus according to claim 4, wherein the white rot fungus is maitake.
The ethanol production apparatus according to any one of claims 2 to 5, further comprising ultrafiltration means for recovering the cellulolytic enzyme by ultrafiltration of the ethanol-containing filtrate. .
The ethanol production apparatus according to any one of claims 1 to 6, wherein the drying means superheats the ethanol-containing steam generated from the filter cake during drying to a superheated steam state, An ethanol production apparatus comprising a configuration in which the ethanol-containing vapor in a state is brought into contact with the filter cake.
The ethanol production apparatus according to any one of claims 1 to 7, further comprising combustion means for burning a residue obtained by drying the filter cake by the drying means.
A solid-liquid separation process for separating the fermented product after ethanol fermentation into an ethanol-containing filtrate and a filter cake;
A drying step of drying the filter cake,
A method for producing ethanol, comprising: concentrating the ethanol-containing filtrate by distillation in a distillation column to obtain ethanol, and supplying the ethanol-containing vapor generated in the drying step to the distillation column. .
10. The method for producing ethanol according to claim 9, wherein the fermented product is obtained by subjecting a mixture of lignocellulosic biomass, water and cellulose-degrading enzyme to ethanol fermentation with a microorganism.
11. The method for producing ethanol according to claim 10, wherein the lignocellulosic biomass is a fungal bed in which filamentous fungi are being cultured and / or a waste fungus bed of filamentous fungi.
12. The method for producing ethanol according to claim 11, wherein the filamentous fungus is a white rot fungus.
13. The method for producing ethanol according to claim 12, wherein the white rot fungus is maitake.
The method for producing ethanol according to any one of claims 10 to 13, wherein the cellulolytic enzyme is recovered by ultrafiltration of the ethanol-containing filtrate between the solid-liquid separation step and the distillation step. An ethanol production apparatus that performs an ultrafiltration step.
The method for producing ethanol according to any one of claims 9 to 14, wherein, in the solid-liquid separation step, solid-liquid separation is performed until the liquid content of the filter cake is 75 wt% or less. A method for producing ethanol.
The method for producing ethanol according to any one of claims 9 to 15, wherein in the drying step, the ethanol-containing steam generated from the filter cake during drying is superheated to a superheated steam state. A method for producing ethanol, comprising bringing the ethanol-containing vapor in a vapor state into contact with the filter cake.
The method for producing ethanol according to any one of claims 9 to 16, wherein in the drying step, drying is performed until the liquid content of the filter cake reaches 40 wt% to 60 wt%. Manufacturing method.
The method for producing ethanol according to any one of claims 9 to 17, further comprising a combustion step of burning the residue obtained by drying the filter cake in the drying step to obtain combustion energy. A method for producing ethanol.