JPS61254177A - Extraction of ethanol from ethanol-containing liquid - Google Patents

Abstract

PURPOSE:To extract ethanol from an ethanol-containing liquid at a low fuel cost, by placing an evaporation stage of the ethanol-containing liquid before the extraction stage of ethanol. CONSTITUTION:An ethanol-containing liquid is preheated by the heat-exchanger 1 and sent to the evaporator 2. The generated mixture of vapor and liquid is sent to the separator 3 and separated into ethanol-containing steam and concentrated waste liquid. The ethanol-containing steam is compressed by the compressor 4, and the thermal energy generated by compression is utilized in the evaporator 2 and the heat-exchanger 1 to obtain an aqueous solution of ethanol. The concentrated waste liquid is recovered after using its thermal energy in the heat-exchanger 1. The aqueous solution of ethanol is pressurized by the pressure pump 5, sent to the extractor 6, extracted with an extraction solvent, and depressurized by the pressure-reducer 8. The depressurized solution is sent to the separator 9 and separated into ethanol and the regenerated extraction solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is an industrially useful material having an ethanol content of 90% or more by a solvent extraction method from an ethanol-containing liquid having an ethanol content of about 10%, such as alcoholic fermented mash. This invention relates to a method for obtaining highly concentrated ethanol.

Throughout this specification, a "supercritical" state shall mean a state in which the temperature and/or pressure of a substance exceeds its critical point, respectively. In addition, % indicating a ratio is calculated on a weight basis.

Prior art and its problems In the alcohol fermentation method in which ethanol is produced by fermenting starchy raw materials or carbohydrate raw materials, ethanol is produced as an aqueous solution with a content of about 10%. This aqueous solution is usually called "alcoholic fermentation mash," and in addition to ethanol, it contains impurities such as methanol, acetaldehyde, and fusel oil, as well as additives added during the fermentation stage.
Furthermore, it contains solid impurities derived from fermented raw materials.

Conventionally, in order to obtain high-concentration ethanol from such alcohol fermentation mash, a distillation method has been commonly used, as shown in FIG. The flow indicated by the broken line in the figure is a distillation method that has been used for a long time. According to this method,
The ethanol contained in the alcoholic fermentation mash is distilled with steam in the first distillation column in the distillation device (51) and sent to the second distillation column and subsequent ones in the same device (51), and the distilled ethanol is obtained as a product. Ta.

The waste liquid discharged from the bottom of the first distillation column due to this distillation is a dilute liquid with a low content of solid impurities, so it cannot be disposed of as it is in consideration of the impact on the environment. Furthermore, the solid contaminants in the waste liquid can be used as fertilizer or livestock feed, but it is necessary to concentrate the waste liquid for use in these applications. Then, the waste liquid was collected in an evaporator (52) for concentrating the waste liquid.
) to obtain concentrated waste liquid and waste water.

However, in this distillation method, the amount of thermal energy consumed in the distillation apparatus (51) and the evaporator (52), that is, the amount of water vapor consumed, is enormous, and the amount of solid waste in the first distillation column and the evaporator (52) is Since solid matter-containing liquids are handled, scale is generated inside these devices due to solid matter, making it difficult to operate the devices stably, and the scale removal work is complicated.

On the other hand, the flow shown by the solid line in FIG. 5 is a distillation method that somewhat alleviates the problems described in section 2. In this method, the alcoholic fermentation mash is prepared in advance using an evaporator (53) for concentrating the mash.
), and the distillate with increased ethanol content is transferred to the distiller f.
f1 (51), and the remaining concentrated waste liquid was extracted.

The distillation equipment 1ffi (51) used a multi-effect evaporator or a single-effect self-steam mechanical compression evaporator from the viewpoint of energy saving, but it was not possible to consume energy as compressed mechanical power, especially electricity. was significant, and therefore the energy savings could not be said to be sufficient.

In general, distillation methods inevitably consume a large amount of energy. Therefore, there is a need for a method that can obtain high-concentration ethanol with less energy in place of the distillation method.

In recent years, a technique has been known in which a pressurized extraction solvent near the critical point or in a supercritical state is brought into contact with an aqueous ethanol solution, and ethanol is extracted from the aqueous solution into a solvent (Japanese Patent Laid-Open No. 56-56201). Publication No.). There is also a known technique for extracting ethanol from an aqueous ethanol solution using substances such as isobutane, n-butane, and difluoroethane, which are gases at atmospheric temperature and pressure, in the liquid region as extraction solvents. It is being

In the method disclosed in Japanese Unexamined Patent Publication No. 56-56201, as shown in FIG. 6, the following operations are performed. That is, the alcoholic fermented mash is supplied to the extractor (62) by a pump (61), where it comes into contact with an extraction solvent near the critical point or in a supercritical state to extract ethanol from the mash into the solvent. The resulting ethanol-containing solvent is then removed using an extractor (62
) from the top of the column via a pressure reducing valve (63) to a distiller (64), and the product ethanol obtained by distillation of the ethanol-containing solvent is withdrawn from the bottom of the column via a valve (65).

-7~ In addition, the extraction solvent recovered from the top of the distillation column (64) is pressurized by the compressor (66), and the obtained regenerated extraction solvent is transferred to the distillation column (64).
64) through the revoiso (67) and cooler (68), and is circulated to the extractor (62) for reuse.

The raffinate remaining in the extractor (62) is drawn off from the bottom via valves (6).

The solvent extraction method shown in FIG. 6 requires less energy than the distillation method shown in FIG. It required IJ power. Furthermore, in the extraction stage, the alcoholic fermented mash, which has not been subjected to evaporation treatment in advance, is kept from coming into contact with the extraction solvent under pressure, so the raffinate is a dilute liquid with a low solids content, which also requires a large amount of thermal energy for the reasons mentioned above. It was necessary to concentrate the raffinate using Furthermore, in the extraction stage, since solids-containing liquids are handled in this way, there are design constraints and operating conditions constraints, such as being limited to a specific type of extractor.

This invention was made in view of the above-mentioned circumstances, and its first purpose is to provide an ethanol extraction method that can significantly reduce the amount of energy required to extract ethanol from an ethanol-containing liquid such as alcoholic fermented mash. is to provide.

A second object of the present invention is to provide an ethanol extraction method that can produce as a by-product a concentrated waste liquid containing solids, which has high utility value as fertilizer or livestock feed, with low energy consumption.

Furthermore, a third object of the present invention is to provide an ethanol extraction method that can minimize design constraints and operating condition constraints in the extraction stage.

Means for Solving the Problems The ethanol extraction method according to the present invention was designed to achieve the above objects, and includes: a) evaporating an ethanol-containing liquid so that almost the entire amount of ethanol in the liquid is contained; producing a vapor and a concentrated waste liquid, separating the vapor and the concentrated waste liquid; b) compressing the separated vapor; and C) indirectly heat exchanging the resulting compressed vapor with the ethanol-containing liquid of step a). and use the thermal energy from the compression as a heat source for evaporation, and also generate water-soluble ethanol by condensing the compressed vapor, d) pressurize the obtained ethanol aqueous solution, and e) convert the pressurized aqueous solution into a compressed extraction solvent. f) The obtained ethanol-containing extract is depressurized to extract liquid ethanol and gas. (g) generating mechanical energy during depressurization of the ethanol-containing extract in step (f); the electrical energy generated is used for the compression of vapor in step b).

In a preferred embodiment of this invention, the following operations are further performed.

In step a) at least one evaporator is provided for indirectly exchanging heat of the compressed vapor coming from step b) with the ethanol-containing liquid.
A multiple effect evaporator or a combination of this and other evaporators is used.

The mechanical or electrical energy generated in step q) is used to pressurize the aqueous ethanol solution in step d).

The raffinate separated in step e) is fed to a fermentation stage in which an ethanol-containing liquor is produced.

The extracted extraction solvent separated in step f) is compressed and the jqed regenerated extraction solvent is recycled to step e) for reuse as compressed extraction solvent.

The regenerated extraction solvent obtained by compression is recycled to stage e) after heat exchange with the ethanol-containing extract upstream and/or downstream of the vacuum in stage f).

The mechanical or electrical energy obtained in step q) is used to compress the extraction solvent.

Extraction solvents include carbon dioxide at a pressure of about 30 to about 200 atm and a temperature of about -10 to about 150°C, ethane at a pressure of about 20 to about 200 atm and a temperature of about 10 to about 150°C;
Pressure about 10 to about 200 atmospheres and temperature about -10 to about 15
Propane at 0°C, isobutane or normal butane or mixtures thereof at a pressure of about 10 to about 200 atm and humidity of about 0 to about 150°C, ethylene at a pressure of about 20 to about 200 atm and humidity of about 0 to about 150°C, pressure of about 20 to about 20
Preferred are propylene at 0 atm and a temperature of about 0 to about 150°C, difluoroethane at a pressure of about 20 to about 200 atm and a humidity of about 0 to about 150°C, and the like.

According to the ethanol extraction method of this invention, depending on more than the effects of the invention,
Since the ethanol-containing liquid evaporation stage is provided upstream of the ethanol extraction stage, the concentrated waste liquid is separated to reduce the amount fed to the extraction stage, and the extraction solvent, which consumes the most energy, is recycled to the extraction stage. The amount can be reduced, and as a result, the required energy can be saved. Energy is also saved in this respect, since mechanical energy is generated during the depressurization of the ethanol-containing extract, and the same energy obtained or electrical energy generated from this is used to compress the vapor. In this way, by applying the ethanol extraction method of the present invention, the energy required to extract ethanol from the ethanol-containing liquid of alcoholic fermentation mash can be significantly reduced.

In addition, since the evaporation stage of the ethanol-containing liquid was provided upstream of the above-mentioned J: sea urchin extraction stage, by concentrating the same wave, concentrated waste liquid containing solids, which has high utility value as fertilizer and livestock feed, can be produced as a waste liquid with low energy consumption. can live.

In general, in the ethanol extraction method according to the present invention, solids-containing concentrated waste liquid is separated from the ethanol-containing liquid in the evaporation stage upstream of the extraction stage, so solids are not handled in the extraction stage. Therefore, design restrictions and restrictions on operating conditions in the extraction stage due to solids in the ethanol-containing liquid can be minimized.

Furthermore, in the evaporation stage, if a multiple effect evaporator or a combination of this and other evaporators is used, which has at least one evaporator that indirectly exchanges heat with the compressed vapor coming from the compression stage with the ethanol-containing liquid, Further energy saving effects can be achieved.

In addition, when the regenerated extraction solvent obtained by compression is circulated to the extraction stage after heat exchange with the ethanol-containing extract on the upstream and/or downstream side of the pressure reduction of the ethanol-containing extract, the regenerated extraction solvent Energy for cooling can be saved.

Examples Next, examples of the present invention will be shown in order to demonstrate the above effects.

Example 1 In FIG. 1, alcohol fermentation mash is first passed through a preheating heat exchanger (1) to be preheated, and then sent to an evaporator (2) for distillation. As a result, almost all of the ethanol in the mash is evaporated, producing ethanol-containing steam. Then, the gas-liquid mixture in the evaporator (2) is passed through the vapor separator (3).
to separate into ethanol-containing steam and concentrated waste liquid.

The obtained ethanol-containing steam was then passed through a vapor compressor (4
) and compress it. The obtained compressed steam is passed through the evaporator (2) and the preheating heat exchanger (1), and the thermal energy from the compression is used as a heat source for evaporation and a heat source for preheating the mash. As a result, the compressed vapor is condensed and a solid-free ethanol aqueous solution is obtained.

Further, the concentrated waste liquid separated by the steam separator (3) is passed through the preheating heat exchanger (1), and its thermal energy is also used as a heat source for preheating the mash, and then guided to the required part.

The ethanol aqueous solution obtained by condensing the compressed vapor is pressurized by an arm pressure pump (5), and is supplied under pressure to the extractor (6) to avoid contact with the compressed extraction solvent. As a result, ethanol is extracted from the aqueous solution into the extraction solvent. The ethanol-containing extract thus produced is handled from the top of the extractor (6), and the raffinate, which is mainly water, is drawn off from the bottom of the extractor (6) via the valve (7). Here, the pressure in the extractor (6) may be near critical pressure to supercritical pressure, or may be in the pressure range of the pressurized ethanol aqueous solution.

Then, the obtained ethanol-containing extract was put into an expander (
8) to reduce the pressure. Mechanical energy is generated along with this pressure reduction, and this energy is used as driving energy for the vapor compressor (4).

As a result of reducing the pressure of the ethanol-containing extract, the density of the extraction solvent decreases, the solubility of ethanol in the extraction solvent decreases, and the ethanol-containing extract undergoes phase separation into liquid ethanol and gaseous extraction solvent.

The resulting gas-liquid mixture is then passed through an ethanol separator (9)
The liquid ethanol is separated from the bottom and discharged as a product through the valve (10).

The gaseous extraction solvent separated by the ethanol separator (9) is sent to the solvent compression II (11) and compressed, and the obtained regenerated extraction solvent is cooled by the cooler (12) and then transferred to the extractor (
6) and reused as a compressed extraction solvent.

Operation conditions and operation examples In the flow shown in Figure 1, 90% water, 11% ethanol
Alcohol fermentation mash consisting of 0% and 10% solid impurities was supplied to the preheating heat exchanger (1) at a flow rate of 10 tons/hour, and a single-effect self-steam mechanical compression evaporator was used as the evaporator (2). , carbon dioxide at a pressure of 100 atm and a temperature of 60°C was used as the compressed extraction solvent to be circulated to the extractor (6), and the ethanol separator (9) was operated at a pressure of 50 atm and a temperature of 16°C. The circulation rate of the extraction solvent is set as raw material supply amount/extraction solvent circulation rate - about 10,
Ethanol was extracted from alcoholic fermented mash.

As a result, when an expander (8) with an adiabatic efficiency of 80% is used, approximately 410 kW of power is recovered, and when an expander (8) with an adiabatic efficiency of 70% is used, approximately 360 kW of power is recovered. It was done. On the other hand, a single-effect self-steam mechanical compression type evaporator is used as the evaporator (2) as described above, and the vapor compressor (4) has an adiabatic efficiency of 70.
When the evaporation operation was carried out under conditions to evaporate almost the entire amount of ethanol and produce a concentrated waste liquid with a solids content of 50%, the required power was only about 270 kW. Therefore, even considering the energy loss to the surrounding environment, the energy recovered by the expander (8) was sufficient for the energy required for the vapor compressor (4). By supplying this recovered energy to the vapor compressor (4), approximately 25% of the total energy required for the flow shown in FIG. 3 was saved.

Further, when a multiple-effect evaporator is used as the evaporator (2), and in at least one of the evaporations, the compressed steam coming from the vapor compressor (4) is indirectly heat exchanged with the preheated ethanol-containing liquid, Additionally, significant energy savings were achieved (for example, in the case of a triple effect evaporator, 2/3 of the total energy required for the flow shown in Figure 1 was saved).

Comparative Example The flow shown in FIG. 1 saves the total energy required for this flow by installing an evaporation stage of the alcoholic fermentation mash prior to the extraction stage and extracting the concentrated waste liquid produced at this stage. On the other hand, in the flow shown in Figure 7, the evaporation stage is installed downstream of the extraction stage, the alcoholic fermentation mash is directly supplied to the extraction stage, and the dilute raffinate with a low solids content produced here is extracted. It is then concentrated in an evaporation step to obtain concentrated waste liquid and condensed water.

Each element in FIG. 7 is the same as the element with the same reference numeral in FIG. 1, so a description thereof will be omitted.

Flow of Example 1 shown in Figure 1 and Comparative Example 1 shown in Figure 7
Table 1 shows the power consumption and recovery saw for the flow.

Table 1 As is clear from Table 1, in the flow of Example 1 shown in FIG. The load in the extraction stage, which has a high proportion to the load, is reduced, and the power consumption in the same stage is reduced, so overall, the power is reduced by about 10% compared to the flow of the comparative example shown in Figure 7. .

Furthermore, if a multiple effect evaporator is used as the evaporator (2),
Since the power consumption of the vapor compressor (4) is reduced and the difference in power between the vapor compressors (4) for both flows is reduced, the power saving effect in the case of the flow of Example 1 shown in FIG. 1 is further increased. improves.

Next, the reduction of energy for cooling the extraction solvent will be explained.

FIG. 3 shows the thermal process of the flow of Example 1 (FIG. 1) on a Moliere diagram of carbon dioxide. In Figure 3, point (31) is the extractor (6), point (32) is the ethanol separator (9), and point (33) is the solvent compressor (1).
1) shows the state at the exit. In the figure, the cycle that closes with a solid line (point (31) → point (32) → point (33) → point (31)) is the example 1 shown in FIG.
The following thermal process is shown under the above operating conditions according to the above operating conditions (cooling is performed from point (33) to point (31) by cooler (12) in order to match the heat balance in the steady state). .

On the other hand, in FIG.
The cycle closing at point (33')→point (33')→point (31°)) shows the thermal process when a pressure reducing valve is used instead of an expander.

In the flow of Example 1 shown in FIG. 1, it is sufficient that the cooler (12) has the ability to cool the regenerated extraction solvent from point (33) to point (31), and under the above operating conditions, its load is approximately It only costs 350,0OOK ca//hour. In contrast, when using a pressure reducing valve that does not generate mechanical energy, approximately 75.0OOKcal/
It takes time. Therefore, according to the flow of the first embodiment shown in FIG. 1, energy savings of about 50% or more can be achieved.

Example 2 In the flow shown in FIG. 2, the ethanol-containing extract discharged from the extractor (6) is treated with the regenerated extraction solvent in the first auxiliary heat exchanger (13). Heat to around 100 ml.

The heated ethanol-containing extract is then depressurized by an expander (8) to produce liquid ethanol and simultaneously liquefy a portion of the extraction solvent.

This gas-liquid mixture is then heated in the second auxiliary heat exchanger (14) also with the regenerated extraction solvent to evaporate the liquefied extraction solvent, and the gas-liquid mixture is sent to the ethanol separator (9>) to separate liquid ethanol and gas. If the extraction solvent is not liquefied at all due to the pressure reduction of the ethanol-containing extract in the expander (8), the heating of the ethanol-containing extract by the second auxiliary heat exchanger (14) is Not necessarily necessary.

The flow shown in FIG. 2 is particularly effective when the aqueous ethanol solution and the extraction solvent are brought into contact in the extractor (6) in a liquid region near the critical point or in a supercritical state of the extraction solvent.

The other configurations shown in FIG. 2 are the same as those in FIG. 1.

In the flow shown in Figure 2, the pressure and temperature of the compressed extraction solvent are 100 atm and ! Using carbon dioxide at 1f27℃,
Operate the ethanol separator (9) at a pressure of 50 atmospheres,
Ethanol was extracted from the alcoholic fermented mash under the same conditions as in Example 1 except for the above conditions.

FIG. 4 shows the thermal process of the flow of Example 2 (FIG. 2) on a Moliere diagram of carbon dioxide. In the figure, point (41) is the extractor (6), (42) is the inlet of the expander (8), (43) is the outlet of the expander (8), and (44) is the ethanol separator (9), (45). )
shows the state at the outlet of the solvent compressor (11), (46) shows the state at the outlet of the second auxiliary heat exchanger (14), and (47) shows the state at the inlet of the cooler (12), respectively.

In the same figure, the solid line (point (41) → point (42) → point (43) → point (44) → point (45) → point (46) → point (
The cycle closing at point (47) → point (41)) shows the thermal -24 - process under the operating conditions according to the flow of Example 2 shown in FIG. From point (47) to point (41) by instrument (12)
).

On the other hand, the broken line in Fig. 4 (point (41°) → point (42')
) → Point (43') → Point (44°) → Point (45°) → Point (
41')) shows the thermal process when mechanical energy is generated by using an expander instead of the pressure reducing valve (63) in the conventional flow shown in FIG. Point (41') in Figure 4 is the extractor (62) in Figure 6, (42') is the inlet of the distiller (64), and (43)
) indicates the inlet of Compression II (66), (44°) indicates the outlet of the compressor (66), and (45°) indicates the state at the cooler (68).
') to point (41°).

Here, the power required for the solvent compressor (11) in the flow shown in Figure 2 and the power required for the compressor (66) when an expander is used instead of the pressure reducing valve (63) in the flow shown in Figure 6. are equal. Regarding these two flows, the power recovered by the expander and the cooling load required in the cooler were compared. However, the conditions are the same as those in Example 1 (alcoholic fermentation mash flow 1 = 101 ~ n/hr,
The thermal insulation efficiency of the expander - 80%) is the same as that of the expander.

The results are shown in Table 2.

Table 2 As is clear from Table 2, in the flow of Example 2 shown in FIG. 2, the recovered power is more than 2.3 times that of the conventional flow, and the cooling load is about 60%. The reason for this is as follows.

That is, in the flow of Example 2 shown in FIG. 2, as described above, the extraction operation is performed in the liquid region of the extraction solvent, and the preparative operation is performed in the gas region because it is necessary to reduce the density of the extraction solvent. In the gas region, the inclination of the lobby line toward 1 is small (as shown in Figure 4), and the expander (8
) the mechanical energy generated is large. On the other hand, in the conventional flow shown in FIG. 6, when mechanical energy is to be avoided by the expander in the liquid region, the lobby lines (A) (B) (
The slope of C) is large, and the amount of energy recovered by the expander is small.

[Brief explanation of drawings]

1 and 2 are step system diagrams showing the flow of Embodiment 1 and Embodiment 2 of the present invention, respectively, and FIGS. 5 and 6 are step diagrams showing the conventional flow, and FIG. 7 is a step diagram shown for comparison. <1) Preheating heat exchanger, (3) Steam leverator, (4) Steam compressor, (5) Boosting pump, (6) Extractor, ( 7)...Valve, (8)...
・Expander, (9)...Ethanol separator,
(10)...Valve, (11)...Solvent compressor, (12)
)...Cooler, (13)...First auxiliary heat exchanger, (
14)...Second auxiliary heat exchanger. 1. Indication of the incident Patent Application No. 95025 of 1985 2
1. Title of the invention Ethanol extraction method from ethanol-containing liquid 3. Relationship with the amended case Patent applicant f) - Address 1-6-14 Edobori, Nishi-ku, Osaka Name 8 Name (511) Hitachi Zosen Corporation 5 , date of the amendment order: Showa year, month, day 6, number of inventions increased by the amendment (1) The scope of claims shall be corrected as shown in the attached sheet. Claims (1) a) evaporating an ethanol-containing liquid to produce a vapor containing substantially all of the ethanol in the liquid and a concentrated waste liquid, and separating the vapor and the concentrated waste liquid; b) compressing the separated vapor; C) indirectly heat-exchanging the resulting compressed vapor with the ethanol-containing liquid of step a) to use the thermal energy from the compression as a heat source for evaporation; and by condensing the compressed vapor; d) pressurizing the obtained ethanol aqueous solution, e) contacting the pressurized aqueous solution with a compressed extraction solvent to extract ethanol into the same solvent, and separating the resulting ethanol-containing extract and the remaining f) reducing the pressure of the obtained ethanol-containing extract to produce liquid ethanol and gaseous extraction solvent, and separating the ethanol and the extraction solvent into gas and liquid; Q) step f) step b), in which mechanical energy is generated during the depressurization of the ethanol-containing extract in step b), and the same energy obtained or the electrical energy generated therefrom is used for the compression of the vapors in step b); A method for extracting ethanol from an ethanol-containing liquid, characterized in that: (2) in step a), a multi-effect evaporator having at least one evaporator for indirectly exchanging heat with the ethanol-containing liquid for compressed steam coming from step b); 2. A method as claimed in claim 1, in which a vaporizer or a combination thereof with another evaporator is used. (3) The method according to claim 1, wherein the mechanical or electrical energy generated in step q) is used to pressurize the aqueous ethanol solution in step d). 4. The method of claim 1, wherein the raffinate separated in step e) is fed to a fermentation stage in which an ethanol-containing liquor is produced. 5. The method of claim 1, wherein the extraction solvent separated in step f) is compressed and the resulting regenerated extraction solvent is recycled to step e) for reuse as the compressed extraction solvent. (6) The regenerated extraction solvent obtained by compression is transferred to step f).
6. Process according to claim 5, characterized in that it is recycled to step e) after heat exchange with the ethanol-containing extract on the upstream side of the vacuum and/or on the vJl stream side. (7) The mechanical energy (1
6. The method of claim 5, wherein electrical energy is used to compress the extraction solvent. (8) The method of claim 1, wherein the extraction solvent is carbon dioxide at a pressure of about 30 to about 200 atmospheres d3 and a temperature of about -10 to about 150C. (9) The method according to claim 1, wherein the extraction solvent is ethane at a pressure of about 20 to about 200 atmospheres and a temperature of about -10 to about 150°C. (10) The method according to claim 1, wherein the extraction solvent is propane at a pressure of about 10 to about 200 atmospheres and a temperature of about -10 to about 150°C. (11) The method according to claim 1, wherein the extraction solvent is isobutane, normal butane, or a mixture thereof at a pressure of about 10 to about 200 atmospheres and a humidity of about 0 to about 150°C. (12) The method of claim 1, wherein the extraction solvent is ethylene at a pressure of about 20 to about 200 atmospheres and a humidity of about 0 to about 150°C. (13) The method of claim 1, wherein the extraction solvent is propylene at a pressure of about 20 to about 200 atmospheres and a humidity of about 0 to about 150°C. (14) The method according to claim 1, wherein the extraction solvent is difluoroethane at a pressure of about 20 to about 200 atmospheres and a humidity of about 0 to about 150°C.

Claims (14)

[Claims] (1) a) evaporating an ethanol-containing liquid to generate a vapor containing almost all of the ethanol in the liquid and a concentrated waste liquid, and separating the vapor and the concentrated waste liquid; b) separating the vapor from the concentrated waste liquid; c) indirectly heat exchange the resulting compressed vapor with the ethanol-containing liquid of step a) to use the thermal energy from the compression as a heat source for evaporation and to produce aqueous ethanol by condensation of the compressed vapor; , d) pressurizing the obtained ethanol aqueous solution, e) contacting the pressurized aqueous solution with a compressed extraction solvent,
extracting ethanol into the same solvent and separating the resulting ethanol-containing extract from the remaining raffinate; f) reducing the pressure of the resulting ethanol-containing extract to produce liquid ethanol and gaseous extraction solvent; g) generating mechanical energy during the depressurization of the ethanol-containing extract in step f), and using the same energy obtained or electrical energy generated from it in step b); A process for extracting ethanol from an ethanol-containing liquid, characterized in that it consists of several stages, used for the compression of vapor. (2) in step a) using a multiple effect evaporator or a combination thereof with other evaporators having at least one evaporator for indirectly exchanging heat of the compressed vapor coming from step b) with the ethanol-containing liquid; A method according to claim 1. (3) The method according to claim 1, wherein the mechanical or electrical energy generated in step g) is used to pressurize the aqueous ethanol solution in step d). 4. The method of claim 1, wherein the raffinate separated in step e) is fed to a fermentation stage in which an ethanol-containing liquor is produced. 5. The method of claim 1, wherein the extraction solvent separated in step f) is compressed and the resulting regenerated extraction solvent is recycled to step e) for reuse as the compressed extraction solvent. (6) The regenerated extraction solvent obtained by compression is recycled to stage e) after heat exchange with the ethanol-containing extract upstream and/or downstream of the vacuum in stage f). The method described in Section 5. (7) The method according to claim 5, wherein the mechanical or electrical energy obtained in step g) is used for compressing the extraction solvent. (8) The method of claim 1, wherein the extraction solvent is carbon dioxide at a pressure of about 30 to about 200 atmospheres and a temperature of about -10 to about 150°C. (9) The method of claim 1, wherein the extraction solvent is ethane at a pressure of about 20 to about 200 atmospheres and a temperature of about -10 to about 150°C. (10) The method of claim 1, wherein the extraction solvent is propane at a pressure of about 10 to about 200 atmospheres and a temperature of about -10 to about 150°C. (11) The method according to claim 1, wherein the extraction solvent is isobutane, normal butane, or a mixture thereof at a pressure of about 10 to about 200 atmospheres and a temperature of about 0 to about 150°C. (12) The method of claim 1, wherein the extraction solvent is ethylene at a pressure of about 20 to about 200 atmospheres and a temperature of about 0 to about 150°C. (13) The method of claim 1, wherein the extraction solvent is propylene at a pressure of about 20 to about 200 atmospheres and a humidity of about 0 to about 150°C. (14) The method of claim 1, wherein the extraction solvent is difluoroethane at a pressure of about 20 to about 200 atmospheres and a temperature of about 0 to about 150°C.