USRE21727E - Chemical treatment in the manu - Google Patents

Description

' Feb; 25, 19451.V 1 B. RODENB'ERG CHEMICAL TREATMENT IN THE MANUFACTURE 0F ETI-[YL ALCOHOL original Filed May 9, 1953' JLOP TOJEWE? BEE?? JOP TOR/46E Ressued Feb. 25,1941

PATENT OFFICE CHEMICAL TREATMENT 1N THE MANU- FACTURE oF ETHYL Amonoi.

Louis B. Rodenberg, Wyoming, Ohio, assignor to National Distillers Products Corporation, New York, N. Y., a corporation ot Virginia Original No. 2,207,111, dated July 9, 1940, Serial No. 206,871, May 9, 1938. Application for reissue December 26, 1940, Serial No. 371,849

5 Claims.

This invention relates to improvements in the continuous distillation of ethyl alcohol, particularly for beverage purposes. It relates more particularly to improvements in continuous distil- 5 lation operations which enable the production of a product containing radically less organic acids and esters than do products normally obtained.

In the manufacture of alcoholic spirits, it is common practice to produce a beer `containing a relatively small proportion of alcohol by a fermentationprocess, and to subsequently concentrate and purify th`e alcohol by distillation, either by batch operations or by continuous distillation processes. It has long been known that in the production of such spirits, by processes involving either batch or continuous distillation, the 4presence of appreciable quantities oi.' organic acids or esters in the final product is objectionable. More or less satisfactory methable materials in the ilnal 'product where the distillation is carried out in batch operations, have been developed; but so far as I am aware, no satisfactory method has been found to sufllciently minimize the quantities of these materials in the nal product in the processes involving continuous distillation. This difllculty is due mainly to the -fact that the esters have a boiling point very close to that of the alcohol,

which makes their separation in -a continuous distillation unit, such as an alcohol column, very diilicult.

The present invention relates to improvements in the continuous distillation and rectification in the content oi the objectionable esters and organic acids in the nal product without introducing any deleterious materials or causing reactions to take place in the material being distilled which might result in the liberation of deleterious materials or compounds.

It has long been known that in the batch distillation of potable spirits, the content ofesters or organic acids Vin the inal product may be greatly reduced by the addition of alkali to the material being distilled; but such addition of alkali has heretofore been subject to the disadvantage that it has resulted in the liberation of volatile nitrogenous compounds, which Arender a large proportion of the distillate unfit for beverage purposes due to disagreeable odors and taste.

For a clearer understanding of the invention, vreference may be had to the accompanying drawing in which, Figure l is a ilow4 diagram of the ods of reducing the quantity of these objection,

of the spirits which permit a radicalA reduction (o1. zoal-57) apparatus employed in carrying out the process.

In the 'production of ethyl alcohol by continuous distillation, the liquor which is stored in tank III is piped tothe beer distillation column II where it is subjected -to steam distillation. 5 The resulting vapors containing alcohol are conducted through the pipes I2 to the aldehyde column I3. In the aldehyde column the low boiling point impurities, such as aldehydes or the like, are volatilized and removed as the liquor i0 ows down thecolumn. The volatilized impurities are carried off at I4 in the top of the aldehyde column. The partially purified product drawn from the bottom at I5 of the aldehyde column is then introduced into the alcohol coll5 umn I6 where it is distilled and rectied. The liquor in the alcohol column is heated and the resulting vapors proceed upward in the column.

A hot condensate of Ithese vapors is tapped from a plate near'the top of the column and consti- 20 tutes the spirits which may be used for potable or other purposes, and stored in tank I1.

When this process is carried out in accordance with the known practice, the nal product generally 'contains a relatively large amount of 25 esters and organic acids, which are highly objectionable if the product is intended for beverage purposes. These objectionable materials cannot be readily removed by further distillation, because the esters have boiling points very close to 30 that of the alcohol.

In accordance with the present invention, the continuous distillation is carried out in the usual manner, except that a suitable basic material is introduced in ycontrolled amounts to the mate- 35 rial in the aldehyde column, to saponifythe esters and to neutralize the organic acids, Ordinar-ily, the concentration of esters in the aldehyde column .is greatest at the platesl located about at the middle of the upper half of this 40 column, shown in Figure l at I9. The basic material which is mlxed in the mixing tank 20 is conducted to the aldehyde column through the conduit 2I, and there mixes with the liquid nowing down -through the aldehyde column. The 45. Yliquid'from which the volatile materials have been removed during passage down the aldehyde column is continually tested for acidity at I5 where itis discharged from the base of the aldehyde column. The amount of basic material 50 entering the aldehyde column at I9 is regulated in accordancewith the pH value of the discharge at I5, and it is found that to maintain. the pH value of 6.4-6.5 is most advantageous.

In accordance with the present invention, the

the organic acids. Ordinarily, the concentration of esters in the aldehyde column is greatest at the plates located about at the middle of the upper half of this column; and the basic material .is advantageously added at this point.

'I'he amount of reagent added must be carefully controlled, and must not be sufficient to cause the alcohol drawn from the bottom of the aldehydel column to have an alkaline reaction. The reagent saponifles the esters and neutralizes the acids at the point of introduction, with the production of the corresponding salts of the acids, free and combined. -These salts, and any excess of the basic material, being non-volatile, pass down the column, the excess of reagent being neutralized in saponifying esters present in the lower portions of the column, or by reaction with acids present in the lower portions of the column.

The amount of the basic material added shouldl be such that the product withdrawn from the bottom of the column has a slightly acid reaction, as if it has an alkaline reaction, volatile nitrogenous compounds may be formed which contaminate the nal product from the alcohol column. Further, if the product taken from the bottom of the aldehyde column is alkaline in reaction, highly objectionable foaming, which interferes with operation, occurs inthe alcohol column.

'I'he control of the addition of the basic material may be accomplished in various ways. In general, the amount added should be so controlled that the material discharged from the bottom of the aldehyde column has a pH slightly below 7.0,

for example, a'bout 6.5. This may be. accomplished by taking samples of Ythe discharge from time to time and measuring its pH value by any suitable method, as by a potentiometer. Advantageously, the control of the addition of the basic material is automatic, as yby the use of a continuous potentiometer operating to control the addition so that the pH of the discharge is continuously maintained in the neighborhood of about 6.4 to 6.5; that is, slightly below 7.0. With the addition of such controlled amounts of the basic material to the upper part of the aldehyde column, the major portion of the esters are saponifled and the major portion ofthe organic acids are neutralized so that both are effectively removed from the nal product. v

Various basic materials may be used in carrying out the process of the invention, including the alkali metal hydroxides and the carbonated alkalies, such as sodium and potassium carbonates.

They lare advantageously added in aqueuos solution. The advantages of the present invention are illustrated by the following example:

A continuous alcohol distillation unit was operated on production schedule in accordance with common practice, the alcohol being distilled from thbeer in a continuous beer still, the resulting concentrated and partially purified alcohol being' passed through an aldehyde column, with introduction oi the product, from which the more volatile materials had been removed in the aldehyde column, into an alcohol column for rectification and purification. The Iinished product contained 1.2 grams of organic acids and 2.9 grams of esters per hundred liters of liquid. 'Ihe pH continuous distillation is carried out in the usual manner, except that a suitable basic material is addedk in controlled amounts to the aldehyde column, to saponify the esters and to neutralize i value of the discharge from the base of the aldehyde column was about 4.4.

The operation was modied by the introduction into the aldehyde column at a point about mid- Way in the upper half of the column of suilicient sodium hydroxide solution to raise the pH of the discharge to about 6.4 to 6.5. With such operation, the material entering the alcohol column contained but a trace of neutralizable and saponiable constituents and the nal product obtained contained about 1.2 grams of acids per 100 liters and substantially no esters. The product obtained Without the use of the sodium hydroxide was decidedly objectionable organoleptivcally because of its content of esters, whereas the product yobtained when the sodium hydroxide was introduced into the aldehyde column was of excellent quality.

I claim:

1.In a process for producing ethyl alcohol in which a beer containing a relatively small proportion of alcohol is produced by fermentation and distilled to produce an alcoholic product, the alcoholic product passed rthrough an aldehyde column to remove low-boiling impurities, and the alcoholic liquor discharged from vthe aldehyde column is distilledand rectiiied in an alcohol still; the improvement which comprises at least in part saponifying esters and neutralizing organic acids contained in the alcoholic product in the aldehyde column by adding thereto, in the aldehyde column, an alkaline rea-gent, the amount of alkaline reagent added being insufficient to cause the bottom product from the aldehyde column, after the removal of low-boiling impurities, to have an alkaline reaction.

2. In a process for producing ethyl alcohol in which a beercontaining a relatively small proportion of alcohol is produced by fermentation and distilled to produce an alcoholic product, the alcoholic product passed through an aldehyde column to remove low-boiling impurities, and the alcoholic liquor discharged from the aldehyde column is distilled and rectified Ain an alcohol still; the improvement which comprises at least in part saponifying esters and neutralizing organicv acids contained in the alcoholic product in the aldehyde column by adding thereto, in the aldehyde column, an alkaline reagent, the amount o1' alkaline reagent added being such that the bottom product from the aldehyde column, after the removal of low-boiling impurities, has a slightly acid reaction.

3. In a process for producing ethyl alcohol in which a beer containing a relatively small proportion of alcohol is produced by fermentation and distilled to produce an alcoholic product, the

alcoholic product passed through an aldehyde column to remove low-boiling impurities, and the alcoholic liquor discharged from the aldehyde column is distilled and rectied in an alcohol still; the improvement which comprises at least in part saponifying esters and neutralizing organic acids contained in the alcoholic product in .the aldehyde column by adding thereto, in the column to remove low-boiling impurities, and the alcoholic liquor dischargedfrom the aldehyde column is distilled and rectiedin an alcohol still; the improvement which comprises at least in part saponifying esters and neutralizing organic acids contained in the alcoholic product in the aldehyde column by adding thereto. in the aldehyde column at a point where the concentration oi esters is substantially the greatest, an alkaline reagent, the amount of alkaline reagent added being insuflicient to cause the bottom product from the aldehyde column, after the removal of low-boiling impurities, to have an alkaline reaction.

5. In a process for producing ethyl alcohol in which a beer containing a relatively small proportion of alcohol is produced by fermentation and distilled to produce an alcoholic product". 'the alcoholic product passed through an aldehyde column to remove low-boiling impurities, and the alcoholic liquor discharged from the aldehyde column is distilled and rectiiled in an alcohol still; the improvement which comprises at least in part saponifying esters and neutralizing organic acids contained in the alcoholic product in the aldehyde column by adding thereto, in the aldehyde column ata point where the concentration of esters is substantially the greatest, sodium hydroxide, the amount of -sodium hydroxide added being such that the bottom product of the aldehyde column, after the removal of low-boiling impurities, has a pH of about 6.5.

LOUIS B. RODENBERG.

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