JP2013078294A - Apparatus and method for producing ethanol - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and method for producing ethanol in which energy required to circulate and use an enzyme is reduced compared to before.SOLUTION: In the ethanol production apparatus including a distillation tower 11 into which an ethanol-fermented liquid produced by fermentation of a biomass raw material is introduced and in which the ethanol-fermented liquid is distilled to distill ethanol vapor, and a rectification tower 12 for rectifying the ethanol vapor to produce ethanol from the biomass raw material, the ethanol vapor distilled from the distillation tower 11 is directly introduced into the rectification tower 12.

Description

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

As a conventional ethanol production device, the saccharification and fermentation reaction solution is distilled and separated from the fermentation product under conditions where the enzyme is not deactivated, and the enzyme contained in the distillation residue is recycled to the saccharification and fermentation process and / or the preliminary saccharification process. There are known ones that efficiently use expensive enzymes. (For example, refer to Patent Document 1).

JP 2010-17084 A

Here, in general, when distillation is performed using a vacuum distillation column (or vacuum concentration apparatus), in order to recover the enzyme without deactivation, the column bottom temperature is 30 ° C. or higher and lower than 60 ° C., preferably 30 ° C. or higher. It is necessary to maintain at 51 ° C. or lower. However, when energy-saving equipment such as a multi-effect can is introduced in order to prevent excessive evaporation energy, the tower top temperature at that time may be lower than 35 ° C. Therefore, it has been necessary to provide a cooler such as a chiller that consumes more power than a conventionally applied cooling tower (cooling tower) to cool and condense ethanol vapor distilled from the top of the tower.
An object of the present invention is to provide an ethanol production apparatus and an ethanol production method in which heat energy and cooling energy necessary for circulating and utilizing an enzyme are reduced as compared with the conventional art.

The ethanol production apparatus according to the first invention that meets the above-mentioned object is a distillation column in which an ethanol fermentation liquid produced by fermenting a biomass raw material is introduced, the ethanol fermentation liquid is distilled to distill ethanol vapor, and A rectifying tower for rectifying ethanol vapor, and an ethanol production apparatus for producing ethanol from the biomass raw material,
Ethanol vapor distilled from the distillation column is directly introduced into the rectification column.

In the ethanol production apparatus according to the first invention, a compressor that adiabatically compresses the ethanol vapor distilled from the rectifying column;
A first heat exchanger for heating the bottom circulating liquid circulating through the bottom of the distillation tower;
A second heat exchanger for heating the bottom circulating liquid circulating through the bottom of the rectifying tower,
It is preferable that ethanol vapor adiabatically compressed by the compressor serves as a heat source for the first and second heat exchangers.

In the ethanol production apparatus according to the first aspect of the present invention, it is preferable that the distillation column and the rectification column are depressurized by the compressor and the bottom temperature of the distillation column is maintained in the range of 40 ° C to 60 ° C.

In the ethanol production apparatus according to the first aspect of the present invention, further comprising a superheater for heating ethanol vapor rectified by the rectification tower in the previous stage of the compressor,
It is preferable that the ethanol vapor heated by the superheater is sent to the compressor, and the ethanol vapor adiabatically compressed by the compressor serves as a heat source for the superheater.

The ethanol production apparatus according to the first invention further comprises a first preheater for preheating the ethanol fermentation broth introduced into the distillation column,
It is preferable that ethanol vapor adiabatically compressed by the compressor serves as a heat source for the first preheater.

In the ethanol production apparatus according to the first invention, it is preferable that the temperature of the ethanol vapor serving as a heat source of the first preheater is 45 to 100 ° C.

In the ethanol production apparatus according to the first aspect of the invention, a third heat exchanger for heating the bottom circulating liquid circulating through the bottom of the distillation column;
A fourth heat exchanger for heating the bottom circulating liquid circulating through the bottom of the rectifying tower,
The heat sources of the third and fourth heat exchangers are each preferably external steam.

In the ethanol production apparatus according to the first invention, the external steam is preferably reduced-pressure steam.

In the ethanol production apparatus according to the first invention, the temperature of the reduced pressure steam is preferably 45 to 100 ° C.

In the ethanol production apparatus according to the first aspect of the present invention, the low COD waste water that is taken out from the rectification tower can be circulated to a pretreatment step in which a pretreatment for increasing the enzyme reactivity of the biomass raw material is performed.

In the ethanol production apparatus according to the first aspect of the present invention, the low-COD wastewater discharged from the rectification tower can be circulated to a saccharification step for adding a saccharifying enzyme to the biomass raw material to obtain a monosaccharide.

In the ethanol production apparatus according to the first aspect of the present invention, as a rinsing liquid used in a solid-liquid separation step of separating solids from the enzyme-containing concentrated waste liquid removed from the distillation tower, the low COD wastewater removed from the rectification tower It can be circulated.

In the ethanol production apparatus according to the first aspect of the invention, it is preferable that the low COD waste water that is taken out from the rectification tower is treated by a waste water treatment device.

The ethanol production apparatus according to the first aspect of the present invention further comprises a second preheater for preheating the ethanol fermentation broth introduced into the distillation column,
It is preferable that the low COD waste water discharged from the rectification tower serves as a heat source for the second preheater.

The ethanol production apparatus according to the first invention further comprises a third preheater for preheating the ethanol fermentation broth introduced into the distillation column,
It is preferable that the enzyme-containing concentrated waste liquid removed from the distillation tower serves as a heat source for the third preheater.

In the ethanol production apparatus according to the first invention, a blower or a vacuum pump can be used instead of the compressor.

In the ethanol production method according to the second aspect of the invention, the ethanol production method for producing ethanol from an ethanol fermentation liquid produced by fermenting a biomass raw material,
Introducing the ethanol fermentation liquor into a distillation column;
And a step of directly introducing ethanol vapor flowing out of the distillation column into the rectification column.

In the ethanol production method according to the second invention, a step of adiabatically compressing the ethanol vapor distilled from the rectifying column;
Using the adiabatic-compressed ethanol vapor as a heat source, and heating the bottom circulating liquid circulating through the bottom of the distillation tower;
It is preferable that the method further includes a step of heating the bottom circulating liquid circulating through the bottom of the rectifying column using the adiabatic-compressed ethanol vapor as a heat source.

In the ethanol production method according to the second invention, the bottom temperature of the distillation column is preferably maintained in the range of 40 ° C to 60 ° C.

In the ethanol production apparatus according to claims 1 to 16, ethanol vapor distilled from the distillation column is directly introduced into the rectification column. Therefore, since ethanol vapor is not condensed by the cooler, the energy consumption required in the distillation process and the rectification process can be reduced as compared with the prior art. In addition, since the distillation column and the rectification column are directly connected and integrated, the equipment cost can be reduced.

In particular, in the ethanol production apparatus according to claim 2, ethanol vapor adiabatically compressed by the compressor serves as a heat source for the first and second heat exchangers. Therefore, the energy consumption required in the distillation process and the rectification process can be reduced as compared with the prior art.

In the ethanol production apparatus according to claim 3, the bottom temperature of the distillation column is maintained in the range of 40 ° C to 60 ° C. Therefore, the enzyme can be reused because the inactivation of the enzyme is suppressed.

In the ethanol manufacturing apparatus according to the fourth aspect, since the ethanol vapor is heated, the condensation of the ethanol vapor in the compressor can be prevented.

In the ethanol production apparatus according to the fifth aspect, the energy consumed in the distillation step can be reduced as compared with the conventional one by using the ethanol vapor adiabatically compressed by the compressor as a heat source of the first preheater.

In the ethanol manufacturing apparatus according to claim 6, the temperature of the ethanol vapor serving as the heat source of the first preheater is 45 to 100 ° C. Therefore, inactivation of the enzyme is suppressed.

In the ethanol production apparatus according to the seventh aspect, since the heat sources of the third and fourth heat exchangers are respectively external steam, the operation is stabilized in the transient state and the steady state when the ethanol production apparatus is started up.

In the ethanol production apparatus according to the eighth aspect, since the external steam is the reduced pressure steam, it is possible to prevent the temperature of the bottom circulating liquid circulating through the bottom of the distillation tower from rising more than necessary. Therefore, inactivation of the enzyme is suppressed and the enzyme can be reused.

In the ethanol manufacturing apparatus according to claim 9, the temperature of the reduced-pressure steam is 45 to 100 ° C. Therefore, inactivation of the enzyme is suppressed and the enzyme can be reused.

In the ethanol production apparatus according to claim 10, water contained in the biomass material or water added in the process of producing ethanol can be discharged as low COD wastewater, and can be reused in the pretreatment process.

In the ethanol production apparatus according to the eleventh aspect, water contained in the biomass material or water added in the process of producing ethanol can be discharged as low COD wastewater, and can be reused in the saccharification process.

In the ethanol production apparatus according to claim 12, since water contained in the biomass material or water added in the process of producing ethanol can be discharged as low COD wastewater, it can be reused as a rinsing liquid used in the solid-liquid separation process. it can.

In the ethanol manufacturing apparatus according to the thirteenth aspect, since the wastewater treatment of the low COD wastewater is easy, the burden of the waste liquid treatment can be reduced as compared with the conventional case.

In the ethanol production apparatus according to claim 14, the low COD drainage discharged from the rectification column is used as a heat source for the second preheater, so that the energy consumption required in the distillation step can be reduced as compared with the conventional one. .

In the ethanol production apparatus according to claim 15, the enzyme-containing concentrated waste liquid taken out from the distillation tower is used as a heat source of the third preheater, so that the energy consumption required in the distillation step can be reduced as compared with the conventional case. .

In the ethanol production apparatus according to the sixteenth aspect, a blower or a vacuum pump can be applied instead of the compressor.

In the ethanol production method according to claims 17 to 19, ethanol vapor distilled from the distillation tower is directly introduced into the rectification tower. Therefore, since ethanol vapor is not condensed by the cooler, the energy consumption required in the distillation process and the rectification process can be reduced as compared with the prior art. In addition, since the distillation column and the rectification column are directly connected and integrated, the equipment cost can be reduced.

In particular, in the ethanol production method according to claim 18, the adiabatically compressed ethanol vapor heats the bottom circulating liquid of the distillation column and rectification column. Therefore, the energy consumption required in the distillation process and the rectification process can be reduced as compared with the prior art.

In the ethanol production method according to claim 19, the bottom temperature of the distillation column is maintained in the range of 40 ° C to 60 ° C. Therefore, the enzyme can be reused because the inactivation of the enzyme is suppressed.

It is a flowchart of the manufacturing process in the ethanol manufacturing apparatus which concerns on one embodiment of this invention. It is a block diagram of the ethanol manufacturing apparatus.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention. In each drawing, portions not related to the description may be omitted.

An ethanol production apparatus according to an embodiment of the present invention generates ethanol from woody, herbaceous, and paper-based biomass raw materials containing cellulose. As shown in FIG. 1, the ethanol production process includes a pretreatment process P1, a saccharification process P2, a C6 sugar fermentation process P3, a distillation process P4, a rectification process P5, and a dehydration process P6. This manufacturing process further includes a solid-liquid separation process P7 and a C5 sugar fermentation process P8.

In the pretreatment process P1, in order to increase the enzyme reactivity of the biomass material, pretreatment such as heat treatment, chemical treatment, and mechanical treatment is performed on the biomass material.
In the saccharification process P2, saccharification enzymes such as cellulase and hemicellulase are added to the pretreated biomass raw material, and cellulose and the like are hydrolyzed to obtain monosaccharides.

In the C6 sugar fermentation step P3, yeast is added to the saccharified solution containing the monosaccharide obtained in the saccharification step P2, and an ethanol fermentation solution is obtained by fermentation. This ethanol fermentation liquid contains 1 to 10% ethanol. This step may be a simultaneous saccharification and fermentation step (step performed together with the saccharification step P2).

In the distillation process P4, the ethanol fermentation liquid obtained in the C6 sugar fermentation process P3 is distilled to separate ethanol. Specifically, the ethanol fermentation liquor is introduced into the distillation column 11 (see FIG. 2) and distilled, and ethanol vapor is distilled from the top of the column. The ethanol fermentation liquid to be introduced contains saccharifying enzymes such as cellulase and hemicellulase and C5 sugar that has not been fermented in the C6 sugar fermentation process P3. Since cellulase and hemicellulase are deactivated at 60 ° C. or higher, the bottom temperature of the distillation column 11 is adjusted to less than 60 ° C. Since the enzyme deactivates with time even below 60 ° C., the bottom temperature of the distillation column 11 is preferably as low as possible.

In the rectification step P5, the low-concentration ethanol water (ethanol vapor) distilled from the distillation column 11 is concentrated to about 90%. In the dehydration step P6, water is separated from the ethanol (90% ethanol solution) concentrated in the rectification step P5 by membrane separation, azeotropy, or the like.

In the solid-liquid separation process P7, the solid is separated from the enzyme-containing concentrated waste liquid taken out from the distillation column 11 of the distillation process P4.
In the C5 sugar fermentation step P8, the C5 sugar contained in the enzyme-containing concentrated waste liquid from which the solid matter is separated is fermented. The fermentation liquor is circulated to the saccharification process P2.

Next, the distillation process P4 and the rectification process P5 indicated by dotted lines in FIG. 1 will be described in detail.
In this step, distillation and rectification are respectively performed by the rectification column 12 directly connected to the distillation column 11 via the distillation column 11 and the distillation line L1 shown in FIG. The distillation column 11 is a plate column having, for example, four plates.
The bottom temperature of the distillation column 11 is provided in the distillation line L2 of the rectifying column 12 so that the temperature of the distillation column 11 is 40 ° C. or higher and lower than 60 ° C. (preferably 30 ° C. or higher and 51 ° C. or lower) so that the enzyme is not deactivated. The internal pressure is controlled to be reduced by the compressor 20. As described above, since the rectifying column 12 is directly connected to the distillation column 11, the column bottom temperature of the rectifying column 12 is substantially equal to the column bottom temperature of the distillation column 11.

The ethanol fermentation liquid produced in the C6 sugar fermentation process P3 is introduced into the distillation column 11.
The enzyme-containing concentrated waste liquid is discharged from the bottom of the distillation column 11. The extracted enzyme-containing concentrated waste liquid is sent out by the tower bottom circulation pump 22, and a part thereof is reused in the fermenter (not shown) of the C5 sugar fermentation process P8 through the solid-liquid separation process P7.
Part of the enzyme-containing concentrated waste liquid (for example, 0.3 wt%, 354 kg / h) preheats the ethanol fermentation broth via the preheater 23 (an example of a third preheater).
The remainder of the enzyme-containing concentrated waste liquid is heated by heat exchangers (reboilers) 24a and 24b, and circulated to the bottom of the distillation column 11 as a tower bottom circulating liquid.
Note that the heat exchanger 24b (an example of a third heat exchanger) uses, for example, reduced pressure steam (external steam) at 45 to 100 ° C. supplied from a steam line (not shown) as a heat source. Thus, since the heat exchanger 24b using the external steam as a heat source is provided, the operation is stabilized in a transient state and a steady state when starting up the ethanol production apparatus. Moreover, since the heat source of the heat exchanger 24b is 45 to 100 ° C. reduced-pressure steam, inactivation of the enzyme in the enzyme-containing concentrated waste liquid can be suppressed.

Ethanol vapor distills from the top of the distillation column 11. In addition, since the quantity of the ethanol fermentation liquid introduce | transduced into the distillation column 11 and the quantity of the enzyme containing concentrated waste liquid taken out from the distillation tower 11 are preset, the difference becomes ethanol and water to distill. This enzyme-containing concentrated waste liquid amount is set to, for example, 9 times the weight of the pulp produced in the pretreatment step P1. The distilled ethanol vapor is directly introduced into the middle stage of the rectifying column 12 via the distillation line L1.
Accordingly, the ethanol vapor is not directly cooled and condensed by a chiller or the like, but is directly introduced into the rectifying column 12 as it is, so that the energy required for cooling and the thermal energy required for the rectifying column 12 are reduced. it can.

As described above, ethanol vapor is introduced into the rectifying column 12.
From the top of the rectifying column 12, an ethanol solution having an ethanol concentration of about 90% is distilled as ethanol vapor. The temperature of this ethanol vapor is, for example, 19 to 39 ° C., and the pressure is 10 kPaA.
The distilled ethanol liquid is heated by the superheater 26 so as not to condense in the compressor 20. Here, generally, when the ethanol vapor distilled from the top of the rectifying column 12 is condensed, an excessive load is applied to the rotating part such as the impeller (blade part) in the compressor 20, or the condensate leaks from the seal part. Mechanical problems may occur. In the present embodiment, since the ethanol vapor distilled from the top of the rectifying column 12 is heated by the superheater 26, the occurrence of problems due to such condensation can be prevented.
The heated ethanol vapor is further adiabatically compressed by the compressor 20 and the temperature is increased. The temperature of the ethanol vapor on the discharge side of the compressor 20 is maintained in the range of 45 ° C to 100 ° C. The ethanol vapor adiabatically compressed by the compressor 20 serves as a heat source for the superheater 26.
In the present embodiment, only one compressor 20 is provided. Therefore, the reliability of the ethanol production apparatus is improved as compared with the case where a plurality of compressors are provided. Further, the initial cost is reduced as compared with the case where a plurality of compressors are provided.

The ethanol vapor whose temperature has been increased is branched into a distillation line L3 and a reflux line L4.
The ethanol vapor sent to the distillation line L3 preheats the ethanol fermentation liquid introduced into the distillation column 11 through the preheaters (an example of the first preheater) 28, 30 and is dehydrated as a 90% ethanol liquid. It is sent to process P6. In addition, the distillation line L3 pressurized by the compressor 20 is decompressed by the vacuum pump 31.
As described above, the temperature of the ethanol vapor on the discharge side of the compressor 20 is maintained in the range of 45 ° C to 100 ° C. Therefore, inactivation of the enzyme in the ethanol fermentation liquid heated by the preheater 28 using this ethanol vapor as a heat source can be suppressed.

On the other hand, the ethanol baver sent to the reflux line L4 further branches at a branch point A into a line L5 and a line L6.
The ethanol vapor sent to the line L5 passes through the throttle valve 32. The throttle valve 32 can control the throttle amount based on the bottom temperature of the rectifying column 12. After passing through the throttle valve 32, the ethanol vapor is heat-exchanged with the low COD drainage (column bottom circulating liquid) at the bottom of the rectifying column 12 by the heat exchanger 54a (an example of the second heat exchanger) and condensed. And becomes an ethanol solution.
The ethanol vapor passing through the line L6 condenses after becoming a heat source of the heat exchanger 24a (an example of the first heat exchanger).

The line L5 and the line L6 merge at the merge point B. The joined ethanol solution further passes through the throttle valve 34. The throttle valve 34 can control the throttle amount based on the pressure of the ethanol solution. The temperature of the ethanol solution after passing through the throttle valve 34 is, for example, 57 to 70 ° C., and the pressure is 40 kPaA. This ethanol solution is returned to the top of the rectifying column 12.

Low COD (Chemical Oxygen Demand) waste water is discharged from the bottom of the rectifying column 12. The temperature of this low COD waste water is 40-60 degreeC, for example. In FIG. 2, the temperature in parentheses is an example.
Since the low COD wastewater is a distillate from the rectification tower 12, there is no high boiling component, and only a small amount of organic acid, oil, etc. are contained. Therefore, although the COD of the low COD wastewater is about 1000 (mg / L), it can be said that the water is clear and clear. Therefore, as shown in FIG. 1, the low COD wastewater can be recycled in the pretreatment process P1, the saccharification process P2, or the solid-liquid separation process P7. In particular, in the solid-liquid separation process P7, the low COD waste water is used as a rinse liquid. Further, the low COD waste water can be treated by a waste water treatment device (not shown).
The low COD waste water is sent out by the tower bottom circulation pump 51.
Part of the low COD wastewater (for example, 0.01 wt%, 201 kg / h) preheats the ethanol fermentation broth via the preheater 52 (an example of a second preheater).
The remainder of the low COD wastewater is heated by the heat exchangers 54 a and 54 b and circulated to the bottom of the rectifying column 12 as a bottom circulating liquid.
The heat exchanger 54b (an example of a fourth heat exchanger) uses, for example, reduced pressure steam (external steam) at 45 to 100 ° C. supplied from a steam line (not shown) as a heat source. As described above, since the heat exchanger using the external steam as a heat source is provided, the operation is stabilized in a transient state and a steady state when the ethanol production apparatus is started up.

The inventor estimated the energy reduction effect of the ethanol production apparatus according to the above-described embodiment. The results are shown in Table 1.

The raw material is wood chips. The calculation conditions are as follows.
<Calculation conditions>
1. Ethanol fermentation broth: 10,484 kg (ethanol concentration 3%)
2. Enzyme-containing concentrated waste liquid: 8,737 kg
3. Distillation column distilled ethanol: 1,747 kg (ethanol concentration 14%) (= ethanol fermentation liquid 10,484 kg-enzyme-containing concentrated waste liquid 8,737 kg)
4). Low COD wastewater: 1,476 kg (= distillation column distilled ethanol 1,747 kg-90% ethanol solution 271 kg)
5. 90% ethanol solution: 271 kg (244 kg / 90 wt%)
6). Reflux ratio for rectification: 3

In the estimation, electric power energy was converted as 1/3 of steam energy. In addition, the amount of steam used for multiple effects was set to 1/3 of ordinary distillation for triple effects. The chiller COP (Coefficient of Performance) was 1.8. The adiabatic compression efficiency of the compressor was 50%.

In Table 1, Comparative Example 1 is a trial calculation result when distillation is performed simply by steam without providing a multi-effect can. This result is set to 100 which is a reference.
The comparative example 2 is a trial calculation result at the time of distilling combining multiple effects and a chiller. About the comparative example 2, since a tower top temperature will be 35 degrees C or less, a chiller is required and required external energy will be 92 in conversion of a vapor | steam.

In the present embodiment, as shown in FIG. 2, the heat source of the distillation column 11 is covered with ethanol vapor compressed by the compressor 20. At that time, since the heat source of the rectifying column 12 is covered by ethanol vapor flowing out from the distillation column 11, it becomes substantially zero.
However, since the ethanol vapor flowing out from the rectifying column 12 is compressed by the compressor 20, the energy saving effect is 31/100 due to the restriction of the temperature increase of the adiabatic compression.

In addition, this invention is not limited to the above-mentioned embodiment, The change in the range which does not change the summary of this invention is possible. For example, a case where the present invention is configured by combining some or all of the above-described embodiments and modifications is also included in the technical scope of the present invention.
Instead of the compressor 20 in the above-described embodiment, a blower or a vacuum pump may be used.

The ethanol fermentation liquor is heat-exchanged by the preheater 30, the preheater 23, and the preheater 52 provided in parallel. For example, when the cost related to the branching of the ethanol fermentation liquor becomes excessive, these preheaters 30, the preheater 23, and the preheater 52 may be provided in series. Alternatively, some or all of the preheater 30, the preheater 23, and the preheater 52 may be omitted.

11: distillation column, 12: rectification column, 20: compressor, 22: bottom circulation pump, 23: preheater, 24a, 24b: heat exchanger, 26: superheater, 28: preheater, 30: preheater 31: Vacuum pump, 32: Throttle valve, 34: Throttle valve, 51: Tower bottom circulation pump, 52: Preheater, 54a, 54b: Heat exchanger

Claims (19)

An ethanol fermentation liquid produced by fermenting a biomass raw material is introduced, and includes a distillation tower for distilling the ethanol fermentation liquid to distill ethanol vapor, and a rectification tower for rectifying the ethanol vapor, In the ethanol production apparatus for producing ethanol from the biomass raw material,
An ethanol production apparatus, wherein ethanol vapor distilled from the distillation column is directly introduced into the rectification column. The ethanol production apparatus according to claim 1, wherein the compressor adiabatically compresses the ethanol vapor distilled from the rectifying column;
A first heat exchanger for heating the bottom circulating liquid circulating through the bottom of the distillation tower;
A second heat exchanger for heating the bottom circulating liquid circulating through the bottom of the rectifying tower,
An ethanol production apparatus, wherein ethanol vapor adiabatically compressed by the compressor serves as a heat source for the first and second heat exchangers. The ethanol production apparatus according to claim 2, wherein the distillation column and the rectification column are depressurized by the compressor, and a bottom temperature of the distillation column is maintained in a range of 40 ° C. to 60 ° C. Ethanol production equipment. The ethanol production apparatus according to claim 3, further comprising a superheater that heats ethanol vapor rectified by the rectification tower in a stage preceding the compressor,
The ethanol manufacturing apparatus, wherein the ethanol vapor heated by the superheater is sent to the compressor, and the ethanol vapor adiabatically compressed by the compressor serves as a heat source for the superheater. The ethanol production apparatus according to any one of claims 2 to 4, further comprising a first preheater for preheating the ethanol fermentation broth introduced into the distillation column,
An ethanol production apparatus, wherein the ethanol vapor adiabatically compressed by the compressor serves as a heat source for the first preheater. The ethanol production apparatus according to claim 5, wherein the temperature of the ethanol vapor serving as a heat source of the first preheater is 45 to 100 ° C. In the ethanol production apparatus according to any one of claims 2 to 6, a third heat exchanger that heats a bottom circulating liquid circulating through the bottom of the distillation tower;
A fourth heat exchanger for heating the bottom circulating liquid circulating through the bottom of the rectifying tower,
The ethanol production apparatus, wherein heat sources of the third and fourth heat exchangers are external steams, respectively. 8. The ethanol production apparatus according to claim 7, wherein the external steam is a reduced pressure steam. The ethanol production apparatus according to claim 8, wherein the temperature of the reduced-pressure steam is 45 to 100 ° C. The ethanol production apparatus according to any one of claims 2 to 9, wherein the low COD waste water discharged from the rectification tower is subjected to a pretreatment step for performing a pretreatment for enhancing the enzyme reactivity of the biomass raw material. An ethanol production apparatus characterized by being circulated. The ethanol production apparatus according to any one of claims 2 to 10, wherein the low COD wastewater discharged from the rectification tower is subjected to a saccharification step for obtaining a monosaccharide by adding a saccharifying enzyme to the biomass raw material. An ethanol production apparatus characterized by being circulated. The ethanol-producing apparatus according to any one of claims 2 to 11, wherein the low-COD waste water discharged from the rectification column is separated from the enzyme-containing concentrated waste liquid discharged from the distillation column. An ethanol production apparatus characterized by being circulated as a rinsing liquid used in a separation step. The ethanol production apparatus according to any one of claims 2 to 12, wherein the low COD wastewater discharged from the rectification tower is treated by a wastewater treatment apparatus. The ethanol production apparatus according to any one of claims 2 to 13, further comprising a second preheater for preheating the ethanol fermentation broth introduced into the distillation column.
An ethanol production apparatus characterized in that low COD waste water discharged from the rectification tower serves as a heat source for the second preheater. The ethanol production apparatus according to claim 14, further comprising a third preheater for preheating the ethanol fermentation broth introduced into the distillation column.
The ethanol production apparatus, wherein the enzyme-containing concentrated waste liquid removed from the distillation tower serves as a heat source for the third preheater. The ethanol production apparatus according to any one of claims 2 to 15, wherein a blower or a vacuum pump is used instead of the compressor. In an ethanol production method for producing ethanol from an ethanol fermentation liquid produced by fermenting biomass raw materials,
Introducing the ethanol fermentation liquor into a distillation column;
And a step of directly introducing ethanol vapor flowing out of the distillation column into the rectification column. The method for producing ethanol according to claim 17, wherein the step of adiabatically compressing ethanol vapor distilled from the rectifying column;
Using the adiabatic-compressed ethanol vapor as a heat source, and heating the bottom circulating liquid circulating through the bottom of the distillation tower;
And a step of heating the circulating liquid at the bottom of the rectification tower using the adiabatically compressed ethanol vapor as a heat source. The ethanol production method according to claim 18, wherein the bottom temperature of the distillation column is maintained in a range of 40 ° C to 60 ° C.

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