FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. TITLE OF THE INVENTION:
"Process of Production of Neutral Alcohols by Extractive Distillation
Column"
2. APPLICANT
(a) NAME: Avinash G. Patil
(b) NATIONALITY: Indian National
(c) ADDRESS: 15, Yogada, Suvernabaug Colony,
Kothrud,Pune-411004 M.S. India
3. PRREAMBLE TO THE DESCRIPTION
COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.

Process of Production of Neutral Alcohols by Extractive Distillation Column
Field of invention
The present invention relates to production of neutral alcohols, and more particularly, to the production of neutral alcohols by the use of energy efficient extractive distillation column.
Background of the invention
Productions of alcohol involve several columns operating in various combinations. Extractive distillation (ED) is known to provide very good separation of key impurities initially and does away with recycle of these in other column combinations. However, use of ED column has been limited by very high energy consumption associated with this column.
The neutral alcohol is basically a purified, colorless, and odorless ethanol. The neutral alcohol is used for the production of alcoholic beverages such as whisky, gin, vodka and the like. Further, the neutral alcohol is also used in industrial applications where high quality alcohol is required. The typical Indian specifications for Industrial and neutral ethanol are: IS2200 and IS2222. Generally, the neutral alcohol i.e. ethanol is produced from sugar cane molasses as well as starch containing substances like rice, wheat, bajra, maize and the like.
The process of alcohol production first involves fermentation of sugars present in or converted from starch from many substrates. The fermentation generates several chemical impurities other than ethanol. The fermented wash thus has to be refined in suitable distillation section to remove these impurities.

The first stage in distillation section is separation of ethanol from bulk of water, dissolved carbon dioxide, acids and solids in fermented wash. This is generally accompanied by a wash stripping column (also known as beer stripper, analyzer and degasifying column).
The extractive distillation column in wash to rectified spirit (RS) or Wash to extra
neutral alcohol (ENA) schemes makes use of the fact that few high boiling
congeners have different volatilities at different alcohol concentrations. They are
more volatile at lower alcohol concentrations and less volatile at more alcohol
concentrations. The column may have about 40 to 80 stages. The ED column thus
involves addition of water (liquid)at the top of column to manipulate the relative
volatilities of these high boiling congeners. The feed alcohol (about 50% WV)
liquid from stripper (RS scheme) or concentrator (ENA scheme) is fed at about 2/3rd
of column from top. This column may be heated by direct steam injection or
indirectly through Reboiler. This column thus involves proper balancing of water
and heat (steam) to column to keep the column in best working zone. The ED
column separates the feed stream in to two streams. Those are, the column top
stream with alcohol concentration of up to 50% V/V that contains most of the high
boiling fusel oils and the bottom stream having about 4-10% alcohol with very low
congeners as such.
However, the problem with the use of ED column has been with the high energy usage associated with it and need for further concentration of the column top stream.
Drawbacks of the prior art

1. The extractive distillation (ED) involves the alcohol feed stream as liquid. The
bottom stream of ED column contains weak alcohol. This thus involves addition of
large quantities of water at column top. The rectification thus involves very high
energy for boiling this water.
2. The top stream of ED column contains about 20-65% alcohol and other impurities with alcohol. This stream has to be processed further because of the regulations requiring this to be about 90% plus.
3. The conventional ED column is not stable& therefore not always in "best operations zone". The column involves manipulation of column top water flow and heat input vis-a-vis alcohol coming in.
Objects of the invention
An object of the present invention is to provide a process for production of neutral alcohol by an extractive distillation which is energy efficient.
Another object of the present invention is to provide a process for production of neutral alcohol which is stable to operate when compared with classical extractive distillation with liquid alcohol feed.
Summary of the invention
Accordingly, the present invention provides a process for production of neutral alcohol using vapor-liquid (V-L) feed ethanol distillation (ED) column, the process comprising:

feeding fermented wash to a first column (10) for removing non-condensable gases with wash and low boiling impurities as vapor stream from top thereof, and a liquid stream from bottom thereof;
subjecting the liquid stream from the first column (10) to a second column (20) for stripping alcohol from the liquid stream going out therefrom;
concentrating and removing low boiling impurities of the liquid stream received from the second column (20) in top of a third column (30) as heads/impure spirits by using heat of vapors or any additional steam and then impure spirit cut as distillate is taken out therefrom, wherein a stream of liquid from bottom of the third column (30) is passed to a sixth column (60) for stripping of alcohol therein;
extracting the liquid stream received from the third column (30) in a fourth column (40) by water, wherein the water is fed to a top of the fourth column (40);
concentrating the alcohol in liquid feed received from the fourth column (40) to a strength of 95-97% in a fifth column(50) along with the sixth column (60), wherein high boiling fusel oils are concentrated in a middle portion of the fifth column(50) and low boiling impurities near the top portion of the fifth column(50), wherein, impure spirit and the neutral alcohol goes out from the top portion of the fifth column (50) and the fusel oils goes out from the middle portion of the fifth column (50); and
subjecting fusel oils obtained from the fifth column (50) to a decanter (70) wherein the fusel oil splits in to amyl alcohol rich fusel oil and water rich streams after cooling and diluting.
In one aspect, the second column (20) is extracted bya vacuum pump (22) for feeding to the column (40).
In another aspect, the second column (20) is extracted under atmospheric pressure for feeding to the column (40).

Brief description of the drawings
Figure 1 depicts a scheme for novel vapor-liquid (V-L) feed ethanol distillation (ED) column under vacuum, in accordance with the present invention;
Figure 2 depicts a scheme for novel vapor-liquid (V-L) feed ethanol distillation (ED) column under atmospheric pressure condition, in accordance with the present invention; and
Figure 3 depicts a scheme showing various feed entering the extractive distillation (ED) column.
Detailed description of the invention
The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiment.
The present invention provides a process for production of neutral alcohol by an extractive distillation process which is energy efficient. Further, the extractive distillation process for production of neutral alcohol is stable to operate when compared with classical extractive distillation with liquid alcohol feed.
The present invention is now illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the

various figures. These reference numbers are shown in bracket in the following description.
Referring now to figure 1, there is shown a scheme of wash to extra neutral alcohol (ENA) using vapor-liquid (V-L) feed ethanol distillation (ED)column operating under vacuum. Specifically, the figure 1 shows a scheme (100). In the scheme (100), the fermented wash after preheating is fed to a column (10). The column (10) is a degasser column in which non-condensable gases with wash and low boiling impurities are removed as vapor stream from top thereof. Further, liquid stream from bottom of the column (10) goes to a column (20).
The column (20)is an analyzer column which mainly strips alcohol from the liquid stream going out there from and ensures that no ethanol is lost in spent wash exiting from bottom of the column (20).The vapor from the column (20) is extracted by suitable vacuum generating equipment for example, a vacuum pump (22) and fed to the column (40) thereby making possible to operate it at atmospheric pressure with vapor feed. In an embodiment, the column (40)is also operated under vacuum and in that case vacuum pump (22) is not required.
Further, low boiling impurities such as aldehydes, esters are concentrated and removed from top of a column (30) as heads/impure spirits by using heat of vapors or any additional steam and then impure spirit cut as distillate is taken out. Further, a stream of bottom of the column (30) is passed to a column (60) which is extractive column for stripping of alcohol therein.
The column (40) makes use of water as an extractant and the water is fed near a top of the column (40). In an embodiment, the column (40) is provided with enough stages, which separates most of impurities such as low as well as high boiling

impurities than ethanol like aldehydes, esters, propanols, butanols and amyl alcohols as a distillate from the top portion thereof and the relatively pure ethanol stream containing weak ethanol is then fed to a column(50). In an embodiment, the column (40) may be heated by direct steam injection or by indirectly through reboiler.(Hl)
Further , the columns (50) along with column (60) together concentrate alcohol to desired 96% strength and also concentrate high boiling fusel oils in a middle portion thereof and low boiling impurities near the top portion of thereof. There are several streams that go out then from the column (50) and the column (60). Specifically, impure spirit and the neutral alcohol from 3-7 trays goes out from the top portion of the column (50) and the fusel oils goes out from the middle portion of the column (50). Further, lees without any alcohol go out from the bottom of the column (60). The fusel oils obtained from the column (50) is then fed to decanter (70) where the fusel oil splits in to amyl alcohol rich fusel oil and water rich streams if cooled and diluted properly. In an embodiment, the scheme (100) includes several other columns further down the line depending on the feed type such as fusel oil concentration column to concentrate the fusel oil washings from the decanter (70), a simmering/de-methylation column for removal of methanol if the substrate is starch based material, a heads concentration column to concentrate heads and a super rectifying column to further concentrate low boiling impurities.
Referring now to figure 2, there is shown a scheme with vapor- liquid (V-L) feed to a novel ethanol distillation (ED) column operating at atmospheric pressure conditions, in accordance with another aspect of the present invention. Specifically, the figure 2 shows a scheme (200). The figure 2 provides the scheme (200) for wash to extra neutral alcohol (ENA) using a vapor-liquid (V-L) feed novel ethanol distillation (ED) column.

In the scheme (200), the fermented wash after preheating is fed to column (110). The column (110) is a degasser column in which the non-condensable gases with wash and the low boiling impurities are removed as a vapor stream from top thereof. Further, liquid from bottom of the column (110) passes to a column(120). Specifically, the column (120) mainly strips the alcohol from the liquid going out therefrom and ensures that no ethanol is lost in spent wash going out from bottom of the column (120). The low boiling impurities obtained from column (110) are further concentrated in the column (130) by using heat of vapors or any additional steam and then taken out as impure spirit cut as distillate. A stream from the column (130) goes to a column (160) for stripping of alcohol therein.
Further, the vapors from the column (120) are not condensed and fed as vapor feed to a column (140)in vapor form. The column (140)makes use of water as an extractant which is fed near top portion thereof. Further, column (140) is provided with steam in the lower portion thereof.
In an embodiment, the column (140) provided with enough stages, which separates most of low as well as high boiling impurities than ethanol such as aldehydes, esters, propanols, butanols and amyl alcohols as a distillate at the top portion thereof. The scheme (200) includes a decanter (170) to split the fusel oil stream from water rich stream obtained from the column (140). The fusel oil washing can be fed to appropriate column down the line like HCC. The relatively pure ethanol stream containing about 4-10% ethanol is then fed to a column (150). In an embodiment, the column(140)may be heated by direct steam injection or by indirectly through reboiler (111).

The columns (150) and a column (160) together concentrate the alcohol to 95-97% strength and also concentrate balance high boiling fusel oils in column middle and low boiling impurities near top. In an embodiment, the strength of the alcohol is 96%.
There are several streams that go out then from the column (150) and the column (160). In an embodiment, the streams includes an impure spirit from top portion and neutral alcohol from 3-7 trays from top portion of the column (150), the fusel oils from a middle portion of the column (150). Further, a lee stream without any alcohol is exited from a bottom of the column (160). The balance fusel oils are then fed to the decanter (170)which is provided at the column (140) top. Further, there columns further down the line depending on the feed type. However, there is no need for any fusel oil concentration column. The columns that may be added to the scheme (200) includes a simmering/de-methylation column for removal of methanol if the substrate is starch based material, a heads concentration column to remove concentrate heads and a super rectifying column to further concentrate low boiling impurities.
Referring now to figure 3, there is shown a schematic drawing showing different feed entering the extractive distillation (ED) column. Specifically, stream 1 is water added as liquid at near topmost portion of the column. Further, stream 2 and 3 are recycled streams from other columns added as liquid stream near l/3rd portion of column half between stages 5 to 12. Furthermore, stream 4 is a feed stream from analyzer column.( This can be vapor or liquid and added near 2/3rd portion from top that is on actual stages between 54 to 66). In an embodiment, the column may have total 40 to 80 actual stages. The feed streams are added to column at locations as given above. The ED column distillate is mixed with water, cooled and decanted in decanter.

Example 1
The present examples provides the extractive distillation (ED) column operated at a pressure of 1 atmosphere.
When simulated with Chemcad 6.4.2, the top ED stream contains most of higher boiling congeners which then split in water rich and amyl alcohol rich portions as indicated by streams 10 and 11 respectively as shown in figure 3. The heat requirement for this case is 100,000 Kcal/hr.
Main Feed is Vapor, Column operated under atm pressure, Q= 100,000 Kcal/hr

Stream No. 1 2 3 4 5 6 7 8 9 10 11
Temp C 90.00 61.43 66.40 97.30 100.65 89.86 30.00 46.76 30.00 30.00 30.00
Pres bar 1.20 1.40 1.50 1,20 3.00 1.20 1.20 1.01 1.01 1.01 1.01
Total kmol/h 777.13 0.17 33.85 75.75 885.34 1.56 5.55 7.11 7.11 0.45 6.66
Component mole %
Ethanol 0.00 81.32 5.10 25.76 2.41 3.64 0.00 0.80 0.80 3.94 0.59
Water 100.00 18.68 94.18 74.18 97.59 79.36 100.00 95.47 95.47 46.51 98.78
Methanol 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Acetaldehyde 0.00 0.00 0.00 0.02 0.00 0.77 0.00 0.17 0.17 1.44 0.08
Acetone 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.01 0.00
Ethyl Acetate 0.00 0.00 0.00 0.00 0.00 0.03 0.00 0.01 0.01 0.06 0.00
N-Propanol 0.00 0.00 0.08 0.00 0.00 1.68 0.00 0.37 0.37 3.85 0.13
Isobutanol 0.00 0.00 0.09 0.00 0.00 1.79 0.00 0.39 0.39 4.01 0.15
N-Butanol 0.00 0.00 0.00 0-00 0.00 0.12 0.00 0.03 0.03 0.35 0.00
Sec-Butanol 0.00 0.00 0.01 0.00 0.00 0.12 0.00 0.03 0.03 0.34 0.00
Amyl Alcohol 0.00 0.00 0.21 0.01 0.00 4.83 0.00 1.06 1.06 14.95 0.12
Isoamyl Alcohol 0.00 0.00 0.33 0.02 0.00 7.66 0.00 1.68 1.68 24.54 0.13
Example 2
Main Feed is Vapor, Column operated under vacuum, Q= 100,000 Kcal/hr

Stream No. 1 2 3 4 5 6 7 8 9 10 11
Temp C 71.00 61.43 66.40 72.20 86.88 73.79 30.00 41.05 30.00 30.00 30.00
Pres bar 1.20 0.50 1.50 0.45 3.00 1.20 1.20 1.01 1.01 1.01 1.01

Total kmol/h 777.13 0.17 33.85 75.75 885.51 1.39 5.55 6.94 6.94 0.39 6.55
Component mole %
Ethanol 0.00 81.32 5.10 25.76 2.41 1.52 0.00 0.30 0.30 1.60 0.23
Water 100.00 18.68 94.18 74.18 97.58 81.44 100.00 96.28 96.28 45.64 99.29
Methanol 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Acetaldehyde 0.00 0.00 0.00 0.02 0.00 0.93 0.00 0.19 0.19 1.80 0.09
Acetone 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.01 0.00
Ethyl Acetate 0.00 0.00 0.00 0.00 0.00 0.03 0.00 0.01 0.01 0.07 0.00
N-Propanol 0.00 0.00 0.08 0.00 0.00 1.89 0.00 0.38 0.38 4.44 0.14
Isobutanol 0.00 0.00 0.09 0.00 0.00 0.08 0.00 0.02 0.02 0.19 0.01
N-Butanol 0.00 0.00 0.00 0.00 0.00 0.13 0.00 0.03 0.03 0.41 0.00
Sec-Butanol 0.00 0.00 0.01 0.00 0.00 0.13 0.00 0.03 0.03 0.40 0.00
Amyl Alcohol 0.00 0.00 0.21 0.01 0.00 5.27 0.00 1.06 1.06 16.88 0.11
Isoamyl Alcohol 0.00 0.00 0.33 0.02 0.00 8.58 0.00 1.72 1.72 28.57 0.12
Example 3
Main Feed is Liquid, Column operated under atm pressure Q= 856,000 Kcal/hr

Stream No. 1 2 3 4 5 6 7 8 9 10 11
Temp C 71.00 61.43 66.40 86.55 100.62 90.47 30.00 41.79 30.00 30.00 30.00
Pres bar 1.20 1.20 1.50 1.20 3.00 1.20 1.20 1.01 1.01 1.01 1.01
Vapor mole fraction 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Total kmol/h 777.13 0.17 33.85 75.75 885.95 0.95 5.55 6.50 6.50 0.32 6.18
Component mole %
Ethanol 0.00 81.32 5.10 25.76 2.41 0.88 0.00 0.13 0.13 0.69 0.10
Water 100.00 18.68 94.18 74.18 97.58 79.06 100.00 96.94 96.94 49.62 99.41
Methanol 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Acetaldehyde 0.00 0.00 0.00 0.02 0.00 1.63 0.00 0.24 0.24 2.83 0.10
Acetone 0.00 0.00 0.00 0.00 0-00 0.02 0.00 0.00 0.00 0.01 0.00
Ethyl Acetate 0.00 0.00 0.00 0.00 0.00 0.05 0.00 0.01 0.01 0.08 0.00
N-Propanol 0.00 0.00 0.08 0.00 0.00 2.79 0.00 0.41 0.41 4.98 0.17
Isobutanol 0.00 0.00 0.09 0.00 0.00 0.05 0.00 0.01 0.01 0.08 0.00
N-Butanol 0.00 0.00 0.00 0.00 0.00 0.20 0.00 0.03 0.03 0.49 0.00
Sec-Butanol 0.00 0.00 0.01 0.00 0.00 0.19 0.00 0.03 0.03 0.48 0.00
Amyl Alcohol 0.00 0.00 0.21 0.01 0.01 2.19 0.00 0.32 0.32 5.65 0.04
Isoamyl Alcohol 0.00 0.00 0.33 0.02 0.00 12.96 0.00 1.90 1.90 35.07 0.16
Example 4
Main Feed is Liquid, Column operated under vacuum, Q= 856,000 Kcal/hr

Stream No. 1 2 3 4 5 6 7 8 9 10 11
Temp C 71.00 61.43 66.40 62.26 86.88 73.34 30.00 40.82 30.00 30.00 30.00
Pres bar 1.20 0.50 1.50 0.45 3.00 1.20 1.20 1.01 1.01 1.01 1.01
Total kmol/h 777.13 0.17 33.85 75.75 885.53 1.37 5.55 6.92 6.92 0.39 6.53
Component mole %
Ethanot 0.00 81.32 5.10 25.76 2.41 1.44 0.00 0.29 0.29 1.50 0.21
Water 100.00 18.68 94.18 74.18 97.58 81.30 100.00 96.30 96.30 45.97 99.29
Methanol 0.00 0.00 0.00 0.00 0.00 o.oo 0.00 0.00 0.00 0.00 0.00
Acetaldehvde 0.00 0.00 0.00 0.02 0.00 1.13 0.00 0.22 0.22 2.19 0.11
Acetone 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.01 0.00
Ethyl Acetate 0.00 0.00 0.00 0.00 0.00 0.03 0.00 0.01 0.01 0.07 0.00
N-Propanol 0.00 0.00 0.08 0.00 0.00 1.95 0.00 0.39 0.39 4.50 0.14
Isobutanol 0.00 0.00 0.09 0.00 0.00 0.08 0.00 0.02 0.02 0.17 0.01
N-Butanol 0.00 0.00 0.00 0.00 0.00 0.14 0.00 0.03 0.03 0.42 0.00
Sec-Butanol 0.00 0.00 0.01 0.00 0.00 0.13 0.00 0.03 0.03 0.41 0.00
Amyl Alcohol 0.00 0.00 0.21 0.01 0.00 4.92 0.00 0.97 0.97 15.56 0.11
Isoamyl Alcohol 0.00 0.00 0.33 0.02 0.00 8.87 0.00 1.76 1.76 29.18 0.13
Advantages of the invention
1. The use of heat in vapors makes the extractive distillation (ED) column of the present invention very energy efficient and this can lead to wide usage of this art of separating most of impurities before we concentrate the ethanol.
2. The conventional ED column calls for a close control on heat supplied, and with vapor feed, the major heat comes with vapor and thus the parameter of heat input to column becomes insignificant thus allowing the column to run in a stable way.
3. The use of decanter in the scheme (100, 200) of the present invention to split the fusel oils right at top of columns ensure that most of impurities are taken out once for all out of system and with no recycling of impurities makes the spirits

extremely neutral when compared with conventional streams which has fusel oil column bottoms recycle back.
4. The ED Column in schemes(100, 200)of the present invention when used under vacuum operations and When heated by vapor of other columns operating at higher pressure makes the process of ethanol distillation more energy efficient, generally referred as multi-pressure schemes.
5. Another modification in schemes 100, 200 can be the ED top stream can be sent to a separate column in place of Decanter. The column have been in use in earlier practice and is called FOC. But having decanter at ED top separates the impurities once through and prevents recycling plus reducing steam use associated with FOC column.
The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the spirit or scope of the present invention.

I Claim:
1. A process for production of neutral alcohol using vapour-liquid (V-L) feed ethanol distillation (ED)column, the process comprising:
feeding fermented wash to a first column (10) for removing non-condensable gases with wash and low boiling impurities as vapor stream from top thereof, and a liquid stream from bottom thereof;
subjecting the liquid stream from the first column (10) to a second column (20) for stripping alcohol from the liquid stream going out therefrom;
concentrating and removing low boiling impurities of the liquid stream received from the second column (20) in top of a third column (30) as heads/impure spirits by using heat of vapors or any additional steam and then impure spirit cut as distillate is taken out therefrom, wherein a stream of liquid from bottom of the third column (30) is passed to a sixth column (60) for stripping of alcohol therein;
extracting the liquid stream received from the third column (30) in a fourth column (40) by water, wherein the water is fed to a top of the fourth column (40);
concentrating the alcohol in liquid feed received from the fourth column (40) to a strength of 95-97% in a fifth column(50) along with the sixth column (60), wherein high boiling fusel oils are concentrated in a middle portion of the fifth column(50) and low boiling impurities near the top portion of the fifth column(50), wherein, impure spirit and the neutral alcohol goes out from the top portion of the fifth column (50) and the fusel oils goes out from the middle portion of the fifth column (50); and
subjecting fusel oils obtained from the fifth column (50) to a decanter (70) wherein the fusel oil splits in to amyl alcohol rich fusel oil and water rich streams after cooling and diluting.

2. The process as claimed in claim 1, wherein vapors from the second column (20) is extracted by a vacuum pump (22) for feeding to the column (40).
3. The process as claimed in claim 1, wherein vapors from the second column (20) is extracted under atmospheric pressure for feeding to the column (40).

4. The process as claimed in claim 1, wherein the fourth column (40) is provided with stages for separating as a distillate from the top portion thereof.
5. The process as claimed in claim 1, wherein the fourth column (40) is heated by direct steam injection or by indirectly through reboiler.
6. The process as claimed in claim 1, wherein lees without any alcohol go out from the bottom of the sixth column (60).