JPS6211087A - Method of concentrating alcohol - Google Patents

Abstract

PURPOSE:To improve extremely productivity of highly concentrated alcohol, by fermenting alcohol with low concentration to give unrefined alcohol, distilling the alcohol and subjecting the alcohol-containing vapor formed by the distillation to membrane separation treatment. CONSTITUTION:A fermentation raw material such as biomass alcohol, etc. is fed to the fermentation tank 1 and alcohol fermentation is carried out by yeast culture. Then, the unrefined alcohol produced by the fermentation is taken out from the fermentation tank 1 and heated by the preheater 2. Further, the unrefined alcohol is introduced to the flash tank 3 and distilled to form flash vapor comprising the alcohol and water as main components. Then, the formed vapor is fed to the membrane separation tank 5 and subjected to membrane separation treatment, to give continuously highly concentrated alco hol.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for continuously obtaining high concentration alcohol by concentrating low concentration alcohol such as biomass alcohol.

Conventional technology and its problems As a method for obtaining high Li1 alcohol by fermentation method, there is a method that adopts a batch method and does not reuse yeast, which is a fermenting bacteria, as seen in the brewing of alcoholic beverages. When trying to continuously produce fermented alcohol from biomass, it is necessary to use flocculating-sedimenting yeast or immobilized bacterial cells to prevent the bacterial cells from flowing out of the fermenter, and to further reduce the mash in the fermenter. Take out a part of it outside the tank,
A method is being used to prevent the death of bacterial cells and to speed up the fermentation rate by adjusting the alcohol concentration in the tank.

Conventionally, in the continuous production process of alcohol from biomass as described above, as shown in Fig. 7, the mash discharged from the fermenter (71) is led to the distillation column (72) and distilled to reduce the concentration of alcohol. A method was taken to increase the In the same figure, (73) is a capacitor, (74)
) is a reboiler. However, this method requires a large multistage distillation column that consumes a large amount of thermal energy in order to reduce the alcohol concentration to the target value, and since the alcohol/water mixture has an azeotropic point, There was a limit to the concentrated concentration of alcohol in distillation.

The present invention has been made in view of the above points, and an object of the present invention is to provide an alcohol concentration method that can completely overcome problems such as multiple consumption of thermal energy and concentration limits caused by azeotropic points.

Means for Solving Problems In order to achieve the above-mentioned purpose, the alcohol concentration method according to the present invention involves subjecting the mash discharged from the fermenter to evaporation treatment in the continuous alcohol production process, and subjecting the resulting vapor to membrane separation treatment. It is characterized by adding alcohol to obtain high concentration alcohol.

The above-mentioned mash is obtained by extracting a portion of the mash inside the fermenter to the outside of the fermenter, for example, in order to adjust the alcohol concentration in the fermenter to prevent bacterial cells from dying and to speed up the fermentation rate.

In a preferred embodiment of the invention, flash distillation is applied as the evaporation means.

EXAMPLES Next, the present invention will be explained in more detail with reference to examples.

Example 1 In FIG. 1, fermentation raw material biomass is subjected to alcoholic fermentation by culturing yeast in a fermenter (1). A portion of the mash produced by fermentation of the biomass is discharged outside the tank in order to prevent bacterial cells from dying and to speed up the fermentation rate by adjusting the alcohol concentration in the tank. The mash extracted in this way is heated in a preheater (2) and then flashed into a flash tank (3) under reduced pressure. This flash distillation generates flash steam whose main components are alcohol and water, and bacteria and solid components in the mash remain at the bottom of the tank as distillation residue.

The flash vapor passes through a demister (4) in the same type (3) to remove minute droplets in the vapor, and is then led to a membrane separation tank (5).

The inside of the same type (5) is divided into two parts by a permeable membrane (6) into the downstream side and the secondary side, and the pressure on the secondary side is made lower than the pressure on the primary side by a blower, compressor, vacuum pump, etc. There is. Further, as the permeable membrane (6), a silicone rubber membrane is used which selectively permeates alcohol over water. When the flash vapor is supplied to the secondary side of the same type (5), the alcohol content therein preferentially permeates through the permeable membrane 6), and high concentration alcohol vapor is obtained from the secondary side.

-The low concentration alcohol vapor remaining on the next side is removed from the membrane separation tank (5).
After leaving the tank, it is condensed in the condenser (7), the condensate is combined with the distillation residue from the flash tank (3), a part of the combined liquid is returned to the bottom of the fermenter (1), and the rest is Extracted from the system.

The permeable membrane is not limited to those mentioned above, and is selected in consideration of selectivity to permeable substances, permeation rate, etc. Furthermore, if a cellulose acetate membrane that transmits water more selectively than alcohol is used instead of the silicone rubber membrane, high concentration alcohol vapor can be obtained from the negative side.

In the flow shown in FIG. 1, the mash is preheated before it is subjected to flash distillation, so the temperature becomes higher than that during fermentation, and as a result, the microorganisms in the mash may be killed or damaged. In such cases, preheating before flash distillation is omitted, the pressure inside the flash tank is reduced further, flash distillation is performed at a low temperature, and the distillation residue is heated on the way back to the fermenter to adjust the fermentation temperature and the bacterial cells are heated. Measures are taken to prevent death or damage.

Next, the alcohol concentration process will be explained based on FIG. 2 showing the vapor-liquid equilibrium relationship and FIG. 3 showing the separation performance of the membrane. If the alcohol concentration of the liquid phase mash extracted from the fermenter is x8, the alcohol concentration of the gas phase obtained by flash evaporation is YA according to the vapor-liquid equilibrium line in Figure 2.
becomes. In this case, it is necessary that not only the flash vapor but also the minute droplets be completely removed by the de-mister. Next, on the primary side of a membrane separation tank equipped with an alcohol selective permeation membrane having the separation performance shown in Figure 3,
When the above flash steam with alcohol concentration YA is supplied, the separation coefficient tOH/H20 Alcohol wtχ of secondary side steam/Water wt% of secondary side steam Alcohol wt% of primary side steam/Water wtχ of primary side steam is It becomes αA. Therefore, YA-45wt%.

In the case of αA-7.5, the concentration of alcohol obtained on the secondary side is 86 wt%.

Example 2 FIG. 4 shows an example in which two membrane separation layers are arranged in series. The upstream side tank (5) is equipped with an alcohol selectively permeable membrane (6) as in Example 1, and the downstream side tank (21) is equipped with a water selectively permeable membrane (22). ing. The alcohol-containing vapor discharged from the secondary side of the tank (5) on the upstream side is supplied to the downstream side of the tank (21) on the downstream side, and high concentration alcohol vapor is obtained from the same upstream side. Low concentration alcohol vapor flows out from the secondary side of 21) and is condensed in a condenser (23). The other configuration of this embodiment is exactly the same as that of the first embodiment.

This embodiment is particularly suitable when the alcohol concentration of the mash is low and the alcohol concentration cannot reach the target value with one membrane separation tank.

Further, both membrane separation tanks may be equipped with the same type of selectively permeable membrane, or three or more may be provided as necessary.

Example 3 FIG. 5 shows an example in which a membrane separation tank is incorporated into a flash tank. In this example, the demister (3
The upper space of 2) is used as a membrane separation tank (33), and the same type (3
3) is equipped with an alcohol selectively permeable membrane (34). The flash vapor that has passed through the demister (32) is supplied to the secondary side of the membrane separation tank (33), and high concentration alcohol is obtained from the secondary side. By integrating the flash tank and the membrane separation tank in this way, the device can be made more compact and equipment costs can be reduced.

Example 4 This example uses a small distillation column (41) or evaporator shown in FIG. 6 instead of the flash distillation apparatus.

In this case, since there is a heater (42) at the bottom, there is no need to preheat the mash using a preheater. The alcohol/water vapor that comes out of the top of the column is supplied to the primary side of the membrane separation tank, and the distillation residue that comes out of the bottom of the column is returned to the fermentation tank.

In the case of this embodiment as well, a permeable membrane may be provided at the top of the distillation column or evaporator, and a membrane separation tank may be incorporated therein.

In addition to the effects of the invention, according to this invention, the mash taken out from the fermenter is subjected to evaporation treatment, and the generated steam is subjected to membrane separation treatment, so that the bacterial cells and solids in the mash are removed by the evaporation treatment. Components can be separated and removed as distillation residues, and these can be completely prevented from going to the membrane separation process on the downstream side.In addition, flash vapor with a high alcohol concentration is supplied to the membrane separation process. be able to.

Thus, according to the alcohol concentration method of the present invention, in the continuous production process of alcohol, the productivity of highly concentrated alcohol can be greatly improved, and the high consumption of thermal energy as explained at the beginning of this specification can be avoided. The problems of conventional methods such as the concentration limit due to the azeotropic point can be completely eliminated.

[Brief explanation of drawings]

1.4.5 and 6 are flow charts showing Examples 1.2.3 and 4 of the present invention, and FIG.
FIG. 3 is a graph showing the relationship between vapor-liquid equilibrium in an aqueous system, FIG. 3 is a graph showing the relationship between alcohol concentration and membrane separation coefficient, and FIG. 7 is a flow chart showing a conventional example. The above-mentioned multifunctional alcohols (wt,.mu)jJiJ
Figure 3 Figure 5 Figure 6 November 1985 r day 1. Case +7) Table, -++ III Sum 6 Q Year Patent Krim 150917 No. 2,
Title of the invention Alcohol concentration method 3 Relationship with the case of the person making the amendment Patent applicant...? 1-6-14 Edobori, Nishi-ku, Osaka-shi 8.8 Yu (511) Hitachi Gear Ship Co., Ltd. 4th generation
4 non-humans 5. Date of amendment order: October 29, 1985 6. Number of inventions increased by amendment 7. Subject of amendment: Brief description of drawings in the specification. 8. Contents of amendment

Claims (3)

[Claims] (1) An alcohol concentration method characterized in that in a continuous production process of alcohol, the mash extracted from a fermenter is subjected to evaporation treatment, and the resulting vapor is subjected to membrane separation treatment to obtain highly concentrated alcohol. (2) A patent in which the above-mentioned mash is obtained by extracting a portion of the mash from inside the fermenter to the outside of the fermenter in order to adjust the alcohol concentration in the fermenter to prevent the death of bacterial cells and to speed up the fermentation rate. The method according to claim 1. (3) The method according to claim 1 or 2, wherein flash distillation is applied as the evaporation means.