GB2091260A - Purification of fermentation alcohol - Google Patents
Purification of fermentation alcohol Download PDFInfo
- Publication number
- GB2091260A GB2091260A GB8200656A GB8200656A GB2091260A GB 2091260 A GB2091260 A GB 2091260A GB 8200656 A GB8200656 A GB 8200656A GB 8200656 A GB8200656 A GB 8200656A GB 2091260 A GB2091260 A GB 2091260A
- Authority
- GB
- United Kingdom
- Prior art keywords
- column
- alcohol
- reflux
- wash
- feed
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
- C07C29/76—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment
- C07C29/80—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment by distillation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/001—Processes specially adapted for distillation or rectification of fermented solutions
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/14—Fractional distillation or use of a fractionation or rectification column
- B01D3/143—Fractional distillation or use of a fractionation or rectification column by two or more of a fractionation, separation or rectification step
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/34—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping with one or more auxiliary substances
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
- C07C29/76—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment
- C07C29/80—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment by distillation
- C07C29/82—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment by distillation by azeotropic distillation
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Preparation Of Compounds By Using Micro-Organisms (AREA)
Abstract
A process for purifying crude fermentation alcohol by sequential distillation steps using (a) a wash column, (b) a hydroselection still, (c) a reconcentration column and (d) a by-products recovery column characterised in that a purge stream from the heads and/or reflux of each of columns (a), (b) and (d) is fed into a heading column where it is distilled in the presence of at least 0.01% w/w strong alkali, and partially purified aqueous alcohol containing 5000 ppm impurities is withdrawn from the base of this column and recycled to column (a) feed. The strong alkali is suitably alkali metal oxide, hydroxide, carbonate or alkoxide, and is preferably present as 0.1 to 0.5% w/w of the feed.
Description
SPECIFICATION
Purification of fermentation alcohol
The present invention relates to a process for purifying crude fermentation alcohol. In particular, it relates to a process for producing substantially neutral and pure alcohol suitable for potable use.
Fermentation alcohol may be produced from any of a wide variety of raw materials such as for example grain, cane-sugar or beet molasses, and waste starch hydrolysate. In all these cases the raw material is fermented using a variety of enzymes and in the presence of yeast, and the fermented product is subjected to a sequence of distillation and purification steps.The conventional techniques used for purification include the use of a wash column to remove a major proportion of the fusel oils, higher alcohols and some low boilers, a hydroselection still for removal of impurities whose boiling points are close to that of ethanol, a reconcentration column to remove substantially all of the remaining low boilers and higher alcohols and to concentrate into an azeotrope the dilute aqueous alcohol emerging from the hydroselection still and finally a recovery column to recover as far as possible any alcohol inevitably accompanying the impurities removed during the preceding hydroselection purification stage.
Two methods have been proposed for maximising the yield of alcohol and to recover alcohol from the various streams of impurities.
One such method is described in US Patent
No. 2910412 (National Petrochemicals Corp.) in which the impure purge and heads streams are fed into a stripping column, a purified alcohol stream is withdrawn from the base of this column and an impurities stream removed from the top of this column is recycled to the extractive distillation (hydroselection) column.
In another method, described in US Patent
No: 3445345 (Katzen), the impure purge and heads streams are fed into an impuritiesconcentrating tower from the upper portion of which is removed an alcohol stream which is recycled and combined with the crude feed to the extractive distillation column. In this latter process low boiling impurities are recovered as overheads and high boilers from the base of this tower. The best total alcohol recovery achieved is only 98.5% and no indication is given of the impurities present therein.
In the conventional technique of purification employing a wash column, hydroselection still, reconcentration column and recovery column, the alcohol recovered in the recovery column usually contains approximately 2000 to 20,000 ppm of impurities which if recycled through the purification distillation train would give an odorous product unsuitable for potable application. Therefore this alcohol stream is normally suitable only for use as a lower value chemical feedstock, e.g. in the production of acetaldehyde or in methylated spirits.
As a result the actual yield of the relatively higher value potable alcohol of the so called "vodka quality" is only about 90-92%. By "vodka quality" is meant exceptionally neutral and pure spirit (at least 68/proof) which consists of alcohol and water only and contains substantially no unpleasant odour or taste imparting components.
It has now been found that the total yield of the relatively higher value "vodka quality" potable alcohol from the process may be increased from 90-92%, in some cases up to about 99% w/w, by recovering the alcohol escaping along with the various "heads" and purge streams in a partially purified form and recycling the partially purified alcohol back to the conventional distillation process.
Accordingly, the present invention is a process for purifying crude fermentation alcohol by a sequence of distillation steps including:
(a) feeding crude ethanol into a wash column provided with a reflux,
(b) feeding the ethanol azeotrope product from the wash column into a hydroselection still,
(c) feeding the products from the base of the hydroselection still into a reconcentration column from which pure alcohol-water azeotrope is withdrawn as a side stream, said column being provided with a reflus, and
(d) feeding the overheads from the hydroselection still into a by-products recovery column provided with a reflux, characterised in that a purge stream from the heads and/or reflux of each of the wash, reconcentration and recovery columns is fed into a heading column wherein it is distilled in the presence of a strong alkali added to the column in an amount of at least 0.01% w/w based on the impure alcohol fed to the column, and a partially purified aqueous alcoholic stream containing not more than 5000 ppm of mixed impurities is withdrawn from the base of this column and recycled to the feed to the wash column.
The conditions of operation of the wash column, hydroselection still, reconcentration column and the recovery column are all conventional and will be well known to those skilled in the art for producing alcohol-water azeotropes from crude fermentation alcohol.
As mentioned previously, the crude alcohol may be produced by enzymatic fermentation of grain, molasses or waste starch hydrolysate. The novelty of the present invention lies in the use of an additional heading column to partially purify the waste streams from the conventional wash, reconcentration and recovery columns, wherefrom a base product comprising aqueous alcohol containing less than 5000 ppm of impurities is withdrawn and recycled to the wash column along with the normal feed to that still.
The heading column suitably contains at least 30, preferably 40-60 distillation plates.
The crude aqueous alcoholic stream from the various heads and purge streams is introduced into the heading column suitably at plate 32 from the base of the column.
The distillation in this column is suitably carried out at a reflux ratio of at least 20:1, preferably at least 100:1. The distillation temperature is suitably maintained between 83 and 85 C at the base of this column and between 78 and 80'C at the top of the column. The distillation is preferably carried out at atmospheric pressure. The strong base may be added with the feed to the heading column or as a separate stream.
The strong base may be an alkali metal oxide, hydroxide, carbonate or alkoxide, for example sodium hydroxide or potassium hydroxide added as an aqueous solution. The amount of strong base added should at least be 0.01% w/w of the alcohol feed and is preferably in the range 0.1 to 0.5% w/w of the feed.
The partially purified aqueous alcohol withdrawn from the base of the heading column suitably is of the same or better quality than that being fed into the hydroselection still from the wash column. Thus it should not contain more than 5000 ppm, preferably not more than 1000 ppm of mixed inpurities. In order to achieve this it may be desirable to remove between 2 and 10% v/v of the feed to the heading column as distillate.
The partially purified aqueous alcohol withdrawn from the base of the heading column is fed to the wash column either combined with the feed to that column or separately.
Thereafter, the purified dilute aqueous alcohol emerging from the wash column is fed to the hydroselection still and the base product from the hydroselection still is fed to the reconcentration column at just below its midpoint and an improved yield, e.g. 99% w/w, of potable alcohol recovered from the upper half of the reconcentration column.
This treatment is particularly effective in removing low levels of odorous impurities which are separated together with the strong base in the wash column base product.
The process of the present invention is further illustrated with reference to the following Example.
Example
Crude fermentation alcohol was purified in a distillation train which is illustrated as a flow diagram in the accompanying Figure. The distillation train consisted of a wash column 1 provided with reflux control, a hydroselection still 2, a reconcentration column 3 provided with reflux control, a by-products recovery column 4 provided with reflux control and a heading column 5 provided with reflux control. Aqueous sodium hydroxide solution (47% w/w) was added to the heading column feed by line 18 to give a concentration in the feed of 0.2% w/w sodium hydroxide. Crude fermentation alcohol wash containing 7-8% w/w ethanol was fed by line 6 to the wash column 1 at a rate of 3t,000 dm3ih. Crude azeotrope ethanol from the wash column 1 was withdrawn by line 7 and sent to the hydroselection still 2 for removal of low boiling impurities overhead.The purified aqueous ethanol from the base of the hydroselection still 2 was fed by line 8 to the reconcentration column 3 from which purified azeotrope ethanol of "vodka quality" was removed as a side stream near the top of the column by line 9.
The hydroselection heads stream was fed by line 10 to the by-products recovery column 4 from which a side stream was recycled by line 11 to the feed to the wash column 1. The byproducts recovery column head stream (line 12) was combined with the wash column head stream (line 13) and the reconcentration column head stream (line 14) and fed to the heading column 5 by line 15 for recovery of the ethanol content which was recycled by line 16 to the feed to the wash column 1. The heading still 5 was operated at a reflux ratio of 120:1 to 160:1 with 10% v/v of the feed removed as heads by line 17. On recycle of the "headed" alcohol from the base of the heading column to the wash column 1 the total yield of "vodka quality" alcohol was increased to about 98%. The permanganate time of the product was 40 minutes.
Claims (5)
1. A process for purifying crude fermentation alcohol by a sequence of distillation steps including:
(a) feeding crude ethanol into a wash column with a reflux,
(b) feeding the ethanol azeotrope product from the wash column into a hydroselection still,
(c) feeding the products from the base of the hydroselection still into a reconcentration column from which pure alcohol-water azeotrope is withdrawn as a side stream, said column being provided with a reflux, and
(d) feeding the overheads from the hydroselection still into a by-products recovery col
umn provided with a reflux, characterised in that a purge stream from the
heads and/or reflux of each of the wash, reconcentration and recovery columns is fed
into a heading column wherein it is distilled in the presence of a strong alkali added to the
column in an amount of at least 0.01% w/w
based on the impure alcohol fed to the col
umn, and a partially purified aqueous alco
holic stream containing not more than 5000
ppm of mixed impurities is withdrawn from the base of this column and recycled to the feed to the wash column.
2. A process according to claim 1 wherein the heading column contains at least 30 distillation plates.
3. A process according to claim 1 or 2 wherein the distillation in the heading column is carried out at a reflux ratio of at least 20:1, and the distillation temperature is maintaned between 83 and 85 C at the base of this column and between 78 and 80 C at the top of the column at atmospheric pressure.
4. A process according to any one of the preceding claims wherein the strong alkali is added with the feed to the column.
5. A process according to any one of the preceding claims wherein the strong base is an alkali metal oxide, hydroxide, carbonate or alkoxide and is added as an aqueous solution in a concentration of between 0.1 and 0.5% w/w of the impure alcohol feed to the column.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8200656A GB2091260A (en) | 1981-01-10 | 1982-01-11 | Purification of fermentation alcohol |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8100726 | 1981-01-10 | ||
| GB8200656A GB2091260A (en) | 1981-01-10 | 1982-01-11 | Purification of fermentation alcohol |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2091260A true GB2091260A (en) | 1982-07-28 |
Family
ID=26278077
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8200656A Withdrawn GB2091260A (en) | 1981-01-10 | 1982-01-11 | Purification of fermentation alcohol |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2091260A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2686071C1 (en) * | 2019-02-15 | 2019-04-24 | Общество с ограниченной ответственностью "АГ ОРГАНИКС" | Method of purifying a fraction of head ethyl alcohol |
| USD862834S1 (en) | 2016-06-27 | 2019-10-15 | Mondelez Europe Gmbh | Cracker |
| USD879408S1 (en) | 2016-06-06 | 2020-03-31 | Mondelez Europe Gmbh | Cracker |
| USD887666S1 (en) | 2017-05-19 | 2020-06-23 | Generale Biscuit | Food bar |
| WO2020126374A1 (en) * | 2018-12-20 | 2020-06-25 | IFP Energies Nouvelles | Method for treating an alcohol feedstock for the production of olefins |
| RU2775964C1 (en) * | 2021-04-30 | 2022-07-12 | Андрей Вячеславович Аристов | Method for purifying alcohol production waste |
-
1982
- 1982-01-11 GB GB8200656A patent/GB2091260A/en not_active Withdrawn
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| USD879408S1 (en) | 2016-06-06 | 2020-03-31 | Mondelez Europe Gmbh | Cracker |
| USD862834S1 (en) | 2016-06-27 | 2019-10-15 | Mondelez Europe Gmbh | Cracker |
| USD887666S1 (en) | 2017-05-19 | 2020-06-23 | Generale Biscuit | Food bar |
| USD1037604S1 (en) | 2017-05-19 | 2024-08-06 | Generale Biscuit | Food bar |
| WO2020126374A1 (en) * | 2018-12-20 | 2020-06-25 | IFP Energies Nouvelles | Method for treating an alcohol feedstock for the production of olefins |
| FR3090393A1 (en) * | 2018-12-20 | 2020-06-26 | IFP Energies Nouvelles | Process for treating an alcohol charge for the production of olefins |
| CN113453775A (en) * | 2018-12-20 | 2021-09-28 | Ifp 新能源公司 | Process for treating an alcohol feedstock for the production of olefins |
| US11993559B2 (en) | 2018-12-20 | 2024-05-28 | Total Research & Technology Feluy | Method for treating an alcohol feedstock for the production of olefins |
| RU2686071C1 (en) * | 2019-02-15 | 2019-04-24 | Общество с ограниченной ответственностью "АГ ОРГАНИКС" | Method of purifying a fraction of head ethyl alcohol |
| RU2775964C1 (en) * | 2021-04-30 | 2022-07-12 | Андрей Вячеславович Аристов | Method for purifying alcohol production waste |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |