JPS6012968A - Multiple-effect extractive distillation of ethyl alcohol - Google Patents

Abstract

PURPOSE:To provide a remarkably economical process for the production of ethyl alcohol, by operating the unrefined alcohol column, the hydrating extractive concentration column and the fractionating column under different pressures, and passing the vapor of the alcohol in a manner to achieve the multiple-effect. CONSTITUTION:The process is performed by using the unrefined alcohol column 1, the hydrating extractive concentration column 2, and the fractionating column 3. The concentration column 2 is operated under pressure, and the vapor generated from the column is used for the heating of the fractionating column 3 operated under a lower pressure than the column 2. The vapor generated from the column 3 is used for the heating of the unrefined alcohol column 1 operated under a lower pressure than the column 3. Since the unrefined alcohol column 1, the concentration column 2 and the fractionating column 3 are operated in a manner to achieve the multiple-effect, an extremely economical process can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a multiple effect extractive distillation method of ethyl alcohol for economically obtaining high quality ethyl alcohol suitable for use in fermentation liquors and carcasses.

[Technical background of the invention and its problems]

When obtaining diethyl alcohol by fermentation, the raw materials include (1) carbohydrate raw materials, that is, glucose and fructose obtained by saccharifying starch, or glucose obtained by decomposing wood fibers, and sucrose ( (2) hemicellulose raw materials, such as those fermented using waste liquid obtained from the calcium sulfite pulp manufacturing process, and the like.

This type of fermentation liquid contains acetaldehyde, methyl alcohol, etc., which have a boiling point lower than that of ethyl alcohol, and higher alcohols such as butyl alcohol, which have a higher boiling point than ethyl alcohol, and so-called fusel oil.

Generally, these must be removed when producing alcohol for drinking.

By the way, it is known that ethyl alcohol liquid is subjected to fractional distillation in a hydroextraction column in order to separate these impurities with volatility within a narrow range contained in ethyl alcohol that are difficult to separate by normal distillation. .

With this technique down, the alcohol concentration is usually 5-12V.
The following method has been conventionally known as a method for removing impurities from a 1% o1 fermentation liquid to obtain alcohol for drinking.

The first method is to supply the fermentation liquor to the mash tower (a tower that supplies fermentation liquor/mash), discard the distillation waste liquor that does not contain dialcohol from the bottom of the tower, and remove all the impurities that were supplied from the top of the tower. An aqueous solution of ethyl alcohol is obtained, transferred to the next extraction column, and warm water is poured into the top of the extraction column to reduce the ethyl alcohol concentration and remove impurities, especially low-boiling substances. If the alcohol concentration is low,
This takes advantage of the fact that it has a high relative volatility relative to ethyl alcohol and is easy to separate. In this way, the ethyl alcohol aqueous solution from which low-boiling substances other than fusel oil have been removed from the top of the column is extracted from the bottom of the extraction column and supplied to the rectification column. In the middle part of this rectification column, depending on the ethyl alcohol concentration, the higher alcohol becomes insoluble in the aqueous solution of canityl alcohol, and forms a two-phase structure, with high volatility relative to water and high volatility relative to ethyl alcohol. The specific volatility is low and there are areas where fusel oil accumulates, and the liquid is extracted from these areas and led to the fusel oil separator, where the solubility of the fusel oil is lowered by cooling and water injection, and only the fusel oil is separated. However, the remaining dilute ethyl alcohol solution is returned to the rectification tower. Ethyl alcohol without any impurities is obtained from the top of the rectification tower and used as a product. Since the collected waste water does not contain any impurities, it is returned to the extraction column and used for adding water in the extractive distillation in the same bath. In addition, in such a three-column type, steam is directly introduced into each distillation column, or a boiler is provided for heating.

On the other hand, the above method has a modification example 2.3, in which a concentration tower is provided in addition to the extraction tower to concentrate low-boiling substances. This method is said to be the most advanced and involves two rounds of hydroextractive distillation. In addition, this method is particularly advantageous in terms of energy saving, by pressurizing the extraction tower and the concentration tower, so that the vapor generated from the top of the tower is not directly supplied to the condenser, but instead is sent to the bottom of the rectification tower. The heat of condensation there is used as a heating source for the rectification column. However, although this method is economical because steam is used for dual purposes, there is still much room for improvement because steam is still directly supplied to the mash tower.

One option is the hydroextractive distillation method, which performs hydroextractive distillation twice, but since the number of columns is large9, the amount of steam supplied to the bottom of the distillation column is usually increased accordingly. Construction costs will also increase. Furthermore, with a large number of towers, multiple effects cannot be used.

[Purpose of the invention]

In order to obtain ethyl alcohol for drinking, the hydrodistillation method is essential, but even if quality is the first priority, it does not mean that any amount of steam can be used. From the point of view of effective utilization of steam and heat, it is desirable to connect all of the groups in a multifunctional manner, and this is the object of the present invention to solve the problem. That is, an object of the present invention is to provide a multiple-effect extractive distillation method for ethyl alcohol that can complete a process that is extremely energy-saving by varying the pressure of each group and making the flow of steam multiple-effect. It is said that [Summary of the Invention] The first invention to achieve this object is equipped with a mashing column, a hydroextraction concentration column, and a rectification column, and pressurizes the hydroextraction concentration column to remove the vapor generated therefrom. It is characterized in that it is used to heat a rectification column that is operated at a lower pressure than the same bath, and the vapor generated from the rectification column is used to heat a mash column that is operated at a lower pressure than the same bath.

Further, the second invention is provided with a mashing tower, a water extraction tower, a concentration tower, and a rectification tower, the water extraction tower and the concentration tower are pressurized, and the vapor generated from these is operated at a lower pressure than both the towers. Both columns are used to heat the rectifying column, and the vapor generated from the rectifying column is used to heat the mashing column, which is operated at low pressure.

As described above, the present invention basically consists of a mash tower, a hydroextraction concentration column (or a hydroextraction column and a concentration column), and a rectification column. The rectification tower is under normal pressure, and the mash tower is under vacuum (reduced pressure). The top temperature of the rectification column is higher than the temperature at the bottom of the mashing column, and the live steam is fed to the bottom glue boiler of the hydroextraction/concentration column (or the hydroextraction column and concentration column) or directly. By blowing O, all the columns have multiple effects. [Embodiments of the Invention] Next, the present invention will be explained in more detail with reference to embodiments shown in the drawings. FIG. 1 shows a first specific example corresponding to the first invention, and FIG. 2 shows a second specific example corresponding to the second invention.

<First specific example> In Fig. 1, 1 is a mash tower with vacuum (reduced pressure);
2 is a water extraction concentration column which is subjected to pressurization, and 3 is a rectification column which is subjected to normal pressure.

A vapor pipe 4 at the top of the mashing tower 1 is connected to a vacuum pump 5 of a vacuum generator, and a condenser 6 is provided in the middle of the vapor pipe 4, and a condensate flow pipe 7 is connected to this condenser 6. ing. 8 is cooling water for the condenser 6.

Fermentation liquid 9 is fed to the top of fermentation tower 1. Furthermore, low-pressure steam generated by a condenser boiler 10 (described later) is blown into the bottom of the mash tower 1 via a steam supply pipe 11. The distilled waste liquid from the mashing column 1 is taken out of the system via a pump 12 and a discharge pipe 13. In this mashing tower, alcohol, carbon dioxide gas, and low-boiling components in the fermented liquor supplied are all removed by promoting gas-liquid contact on the trays in the mashing tower 1 by steam blown into the bottom of the tower. The carbon dioxide gas is led to the condenser 6, without being condensed.
It is taken out of the system by the pump 5 of the vacuum generator. On the other hand, some of the ethyl alcohol, higher alcohols, and low-boiling substances condensed by the condenser 6 are refluxed to the top of the mashing column 10 via the reflux pipe 14, and the remainder is extracted by pressurized water through the pipe 16 by the pump 15. It is supplied to the concentration column 2.

The hydroextraction concentration column 2 is divided into an upper concentration section and a lower extraction section, and the crude distillate from the mashing column 1 is supplied to the middle stage thereof. At the same time, a portion of the bottoms from the vasophage tower 3, which will be described later, is also supplied through the hydrogenation pipe 18 by the pump 17. The composition of the bottoms is water containing 0.01 to 0.05 Vo1% ethyl alcohol, and this water is supplied to the upper stage of the extraction section and used for hydroextractive distillation. ,
Medium pressure live steam 2o is blown into the steam blowing pipe 19. In the extraction section, the alcohol concentration is set to 15 to 25 Vo1%, and the specific volatility of low-boiling substances with respect to ethyl alcohol-water is increased to prevent the low-boiling substances from falling to the bottom of the column. It is extracted from the bottom of the column in almost the same state as the top, and is led to the rectification column 3 through the supply pipe 21.

On the other hand, the mixture of low-boiling substances and alcohol concentrated in the concentration section is led to a reboiler condenser (reboiler that also serves as a condenser) 23 attached to the lower part of the rectification column 1 through a steam pipe 22 from the top of the column. A part of the condensed liquid is returned to the top of the column 2 by a pump 24 through a reflux pipe 25, and the remainder is discharged as a distillate 26 to the outside of the system.

The driving force for heat transfer in the reboiler condenser 23 is that the rectification column 3 is operated at normal pressure and the hydroextraction/concentration column 2 is operated at pressurized, so the condensation temperature of the vapor from the hydroextraction/concentration column 2 is as follows.
This is obtained by having a higher evaporation temperature than the liquid composition (approximately 99.9% water) at the bottom of the rectification column 3. Further, in the upper concentration section, there are places where fusel oil accumulates, so the fusel oil is removed by the discharge pipe 27.

The distillate is thus removed, and the liquid containing some fusel oil is led from the supply pipe 21 to the rectification column 3 at normal pressure, where it is subjected to a rectification operation and stripped. A boiler condenser 10 is provided at the top of the rectification column 3, through which cooling water 29 for condensing the vapor passing through the vapor pipe 28 is passed, and in this boiler condenser 10,
Operations are performed to condense the generated vapor and evaporate the cooling water 29 to serve as a heating source for the mash tower 1.

Here, since the operating pressure of the boiler condenser 10 is set to a vacuum that is almost the same as the pressure at the bottom of the mash tower 1, there is a difference between the condensation temperature of the alcohol and the evaporation temperature of the cooling water 29.
Evaporation becomes possible. The condensate from the boiler condenser 10 passes through a line 30, a part of which is returned to the top of the column via a reflux line 31, and the remainder is deposited as a product alcohol free of impurities through a line 32. Further, fusel oil in the rectification column 3 is removed through a discharge pipe 33. The product alcohol may be taken out from the pipe line 34 from a shelf several stages below the top of the column. In this way, pure drinkable alcohol with no impurities is obtained from the upper part, while a portion of the alcohol-free bottom liquor from the lower part is used for adding water in the extractive distillation as described above, and the remainder is sent to the thread via the pipe 35. Second specific example> In the three-column distillation method in the above example, in the concentration section for concentrating the initial distillate in the upper part of the hydroextraction/concentration column 2, the concentration of the initial distillate should be increased and removed. In this case, the first distillate will fall to the extraction part! In order to prevent a certain amount of alcohol, it is preferable to extract a large amount of alcohol with a small amount of initial distillate. Become. Therefore, it is preferable to provide a concentration column 2B for removing only the initial distillate separately from the hydrolysis extraction column 2A as described below.

In FIG. 2, the same reference numerals are given to the same functional parts as in the first embodiment. In addition, water extraction extraction 2A and concentration tower 2
Both columns B and B are operated under pressure. The vapor distilled by the steam 20A in the water extraction column 2A passes through the steam pipe 22A to the reboiler attached to the lower part of the rectification column 3. After being guided to the condenser 23A and condensed and used for heating, the steam pipe 22 is pumped by the pump 24A.
'A is supplied to the middle stage of the concentration column 2B. A portion is refluxed through the reflux tube 25A. In the concentration tower 2B, the initial distillate is concentrated together with ethyl alcohol by the steam 20B supplied to the bottom, and the generated vapor is led to the reboiler condenser 23B via the steam pipe 22B, and the condensation heat is transferred to the rectification tower 3. After being supplied to the lower part of the pump 24B, a portion is refluxed through the reflux tube 25B, and the remainder is taken out of the system as an initial distillate. The fusel oil and the alcohol reduced in initial distillate in the concentration column 2B are extracted from the middle stage and returned to the hydroextraction column 2A through the return pipe 36. The bottoms with a low alcohol content at the bottom of the concentrating column 2B are extracted out of the system via the discharge pipe 37.On the other hand, not only the top product from the extraction column 2A is sent to the concentrating column 2B. , in the rectification column 3, from the top of the column 5 to
By obtaining the product alcohol from the bottom of the 6th stage and using the 5th to 6th stage for concentrating the initial distillate, alcohol with a high initial distillate concentration can be obtained from the boiler condenser 10.
By supplying alcohol through the L pipe line 32'', the quality of the product alcohol can be improved. Note that this method can be similarly applied to the first specific example.

<Modification> In each of the above-mentioned sides, the vapor of the rectifying column 3 is led to the boiler condenser 10 to generate low-pressure steam to serve as a heating source for the mashing column. It can also be supplied to a boiler condenser attached to the lower part of the tower and used as a heating source.

〔Example〕

An example using the same three-column system plant as shown in FIG. 1 will be described. The moromi tower has a diameter of 250 mm.
Donatuba, full tower with 40 trays of mmφ,
The mash tower condenser has a heat transfer area of 2 n/, uses cooling water at 22°C, and has a tower top pressure of 80+intestinal Hg and a tower bottom pressure of 1
At 88 Hg, the steam generated from the top of the rectification column and the boiler condenser was guided to the bottom, and fermented mash with an alcohol content of 8Vo1% made from cane molasses was preheated to a temperature of 40°C and supplied to the mash tower. . The alcohol concentration in the waste liquid discharged from the bottom was 0.03 wt%, and there was no reflux at the top of the column, yielding 43 wt 9f+ alcohol, which was passed through a perforated column with a diameter of 200 cm and an opening ratio of 10. The water is supplied to a hydroextraction concentration column (extraction section 12 stages, condensation section 40 stages), and at a top pressure of 55 gauge and almost total reflux, the
The first distillate was removed at a rate of 0.2% of the amount of alcohol supplied. The alcohol concentration at this time is 9Vo1
It was 4. In the extraction section, the bottoms of the rectification column are
It was returned at a rate of 0 to 12.6/hr to maintain the concentration in the extraction section at 8 to 12 wt%, and υ of the bottoms from the extraction column was sent to the middle stage of the rectification column. The rectification column was operated at an atmospheric pressure at the top and a reflux ratio of 4.5. Heating of the bottom part was carried out by putting one pot of the extraction column in a reboiler condenser.The heating temperature was 138 to 140°C, and the temperature at the bottom of the rectification column was 108°C. 95 Vol at the top of the tower or the 6th step
% concentration of product alcohol 14.5-15, OkV
In the middle row, fusel oil is added at a ratio of about 5% to alcohol production by 3.
It was pulled out about once every 0 minutes. The obtained product alcohol contains acetaldehyde of 01m9/1001nl or less, organic acid of 0.002wt% or less, and fusel oil of 0.002wt.
%, and a product comparable to that of the conventional method for beverage use was obtained.
A 0kW electric heater was used. The power consumption under the above operating conditions is 25 kW, which is 43.5 to 9 Ar in terms of steam at 5 Bar gauge pressure, and this value is 2.
3T steam/KL100tI) For alcohol and beverage alcohol production, conventional 4.0 to 5. It was found to be very economical compared to OT/KL. In addition, in this book, by forcing heat retention to prevent heat radiation, the difficulty of distillation operation due to heat radiation 7! I;
[Effects of the Invention] As described above, according to the present invention, since the mashing column, the first distillate column, and the rectifying column are configured to have multiple effects, it is possible to obtain a significantly economical process. .

[Brief explanation of the drawing]

FIG. 1 is a flow sheet of the first invention example, and FIG. 2 is a flow sheet of the second invention example. l... Moromi tower 2... Water addition extraction concentration tower 2A... Water addition extraction tower 2B... Concentration tower 3... Rectification tower 5... Vacuum pump 9... Fermented liquid (mash) 10... Boiler condenser 20... Live steam 23,23A. 23B...Reboiler patent applicant Tsukishima Kikai Co., Ltd.

Claims (1)

[Scope of Claims] (Re) A rectifier comprising a mashing column, a hydroextraction concentration column, and a rectification column, which is operated at a lower pressure than the four A multiple-effect extractive distillation method for ethyl alcohol characterized in that the vapor generated from the rectification column is used to heat the fermentation column operated at a lower pressure than the four units. (2) Morification column The water extraction tower and the concentration tower are pressurized, and the vapor generated is heated by the rectification tower operated at a lower pressure than the two towers. A multiple-effect extractive distillation method for ethyl alcohol, characterized in that the vapor generated from the rectification column is used to heat four mash columns operated at low pressure.