Improvements in the Treatment of Commercial Alcohols.
Year: 1889

page_text: Date of Application, 15th Jan., 1889
Complete Specification Left, 15th Oct., 1889-Accepted, 14th Dec., 1889
PROVISIONAL SPECIFICATION.
Improvements in the Treatment of Commercial Alcohols.
I, HUGUES ERNEST SOREL, ex-Engineer of State Manufactures, residing at
No. 59er Rue Buonaparte, Paris, in the Republic of France, do hereby declare the
nature of this invention to be as follows :—
In the rectification or dephlegmation apparatus with trays or with balls, used in the
concentration or purification of alcohol or similar products, the practice is to create,
by means of a special appliance," the analyser," a considerable reflux of highly con-
centrated liquid at the top of the column, in order to check the appearance of the
slightly volatile compounds which characterise the products called tail-products
("queue").
This reflux envolves a very considerable increase in the cost of fuel, inasmuch as
all the liquid brought back by retrogradation into the column has to be evaporated
afresh.
As it is difficult to alter the heat surface of the apparatus, the productive capacity
of this apparatus is therefore diminished when the retrogradation is increased.
Now the reflux only has the result of lowering the temperature of the stages of the
column and plays no other part. Its absolute quantity is not therefore to be con-
sidered, if we can act in another way on the temperature of the column.
I have moreover observed that the object aimed at is not indeed fully attained by
the use of this costly process, and that by adopting the improvement hereinafter
described, the appearance of the tail products can be still more retarded and in a more
economical fashion.
But first of all I will give a few theoretical indications, so as not to have to revert
thereto in the technical description.
The volatile impurities, without chemical action on the alcohol, contained in the
alcoholic vapours, are divided, at each stage of the dephlegmation or rectification
column, between the non-condensed vapours which traverse that stage and the liquids
which arise from the condensation in the upper stages. For each temperature, there
is a fixed proportion between the quantity of a given impurity contained in a kilogram
of vapours and the quantity of the same impurity contained in a kilogram of the liquids
in contact with those vapours.
If therefore, we suppose a section of the column such that the temperature is appre-
ciably uniform from top to bottom, we shall have the equation:
the proportion
in which s represents the proportion of impurity in the upper stage, s
of the samo impurity in the lowest stage, in the number of stages, K the coefficient
of division of the impurity between the vapours and the liquid, p the weight of the
vapours traversing each stage in an unit of time, and P the weight of the liquids
traversing it in an unit of time.
Thus the proportion of s, to sm, or, if you like, the velocity of conveyance of the
impurities from the bottom to the top of the column, does not depend on K, nor on p,

page_text: nor on P, taken each separately, but rather on the proportion K +, the number of
stages being always supposed to be the same.
Now, I have ascertained, this new fact, that the proportion of is almost independent
of the absolute value of the reflux returning into the top of the column, and only
depends essentially on the temperature of the section considered. This proportion,
very low in the vicinity of 95 to 100° C, increases very rapidly when the temperature
decreases, attains its maximum when the temperature is between 82 and 85° C, and
then decreases with tremendous rapidity as soon as the temperature is below 80° C.
Thus at 79° C, it is four times less than at 83° C.
On the other hand, in proportion as the temperature decreases, the coefficient of
division K diminishes, both because the tension of the vapours diminishes, and because
the concentration of the alcohol, and therefore its dissolving power, increases.
To sum up the term K½ increases in spite of the diminution of K from 90° C
down to 82 or 85° C and then decreases very rapidly from that limit down to 78°.7
the point of ebullition of the most highly concentrated alcohol produced in industrial
apparatus.
The smaller this term is the longer will the tail impurities be retained in the lower
parts of the column and consequently the groater will be the yield of "heart
alcohol."
There is therefore a considerable advantage in lowering the temperature of the
lower stages of the dephlegmation or rectification column, so that throughout the
whole of the column the term K½ shall be as small as possible, in order to retard
or retain the tail products.
On the other hand, provided that the alcoholic vapours to be dephlegmated are
submitted to progressive refrigeration and that the condensed liquid be sent back
into contact with the vapours coming out of the distilling or rectifying boiler the
cost of fuel for one and the same concentration is independent of the manner in which
the refrigeration is effected provided that such refrigeration is strictly confined to
producing one concentration.
Taking these facts as a basis, the most important of which viz. the mode of variation
of the tensions of the impurities was hitherto unknown. I alter the construction
and working of the dephlegmation or rectification columns in the following
manner :-
I reduce the functions of the analyser to the greatest simplicity so that it has only
to maintain the vapours at the temperaturo strictly necessary in order to obtain the
required strength. I therefore create as little reflux as possible.
On the other hand, I establish in the lower stages of the column, a circulation of
water, such that the alcoholic vapours which escape from the last refrigerated stage
have a minimum capacity of 68° G L corresponding under normal pressure to a
temperature of 31° C.
I have found that this system can be easily and economically maintained so long
as the temperature of the vapours issuing from the distilling column or from the
rectifying boiler is below 95°, that the vapours of the refrigerated stages can even be
made to issue at a temperature of 80° up to about that limit.
In short I envelop the not refrigerated part of the column in an insulating jacket
in order to avoid exaggerated condensations and to reduce the reflux to the strict
minimum This precaution enables me considerably to increase the number of stages
without envolving a corresponding increase in the consumption of fuel. Of course
the effect produced will be all the more favourable in proportion as the resistance
offered by the trays or stages to the passage of the vapours is less.

page_text: temperature.
I reserve it to myself to apply to the apparatus according to the various types
thereof any arrangement fulfilling the above data.
I limit myself here to describing the arrangement which seems to me the most
simple and most advantageous and which is represented suggestively in the accom-
panying drawings.
Figure 1 an elevation, partly in section of the apparatus.
Figure 2 section from X to x of Figure 1.
Figure 3 section from Y. to Y of Figure 1.
Figure 4 section from Z to Z of Figure 2 (section on an enlarged scale).
Figure 5. details on an enlarged scale of the testing apparatus and accessories.
Figure 6 view on a larger scale of one of the tubes shown in Figure 3.
The vapours to be concentrated and purified come through the pipe A. into the
first compartiment B of the column where they pass over the surface of the return
liquids which are maintained at a constant level by the waste pipe which terminates
the pipe C, which latter serves to conduct these returns to the rectification boiler or to
the distillation column.
The vapours then enter into the regulating refrigerator. This is formed of two
rectangular sections placed one above the other. The section D is entirely furnished
with little hollow cylinders of glazed earthenware; open at their extremities and
arranged in quincunx form, one above the other, in horizontal stages. This filling
ensures an enormous surface of contact between the liquids and the vapours, while
sufficiently separating them, and creates hardly any obstacle to the passage of the
vapours.
In this first section, the vapours commence to be refrigerated and to be concentrated
in contact with the return liquids.
They then pass into the regulating refrigerator properly so called, E E, consisting
of several horizontal series of rectilineal copper tubes, traversed by the hot water
coming from the analyser. These tubes are very close together and are arranged in
such a way that those of one series correspond to the intervals of the series immo-
diately beneath and of the series immediately above. Their surface is plaited or un-
dulated in such a way that the condensed liquids are obliged to distribute themselves
regularly over all the cylinders of the section D.
The water first of all traverses the first upper series, then the second and so on, in
order to refrigerate the vapours methodically and bring them as economically as
possible to the required temperature. I of course reserve it to myself to add cold
water to the hot water supplied by the analyser, if necessary.
The workman ascertains that the refrigeration is suitable, either by consulting a
thermometer placed in the current of the vapours underneath the grating b b, or better,
by observing the degree of the alcoliol condensed in the refrigerator 1, fed by the
in-take c placed underneath the said grating. This alcohol flows continuously,
enclosed from the air, into the testing glass J, into which an alcohol gauge and a
thermometer dip, and it is brought back to the column by the little, tube d, forming an
hydraulic joint.
After passing through the grating bb, the vapours enter the dephlegmation column
properly so-called, F, which is furnished with the same kind of stack as the section D
and surrounded by an insulating jacket. Then they reach the analyser G, composed
of a group of horizontal plaited or undulated tubes, similar to that which exists
in E.
These tubes are traversed, from the upper stage to the lower stage, by the hot water
coming either from the ordinary refrigerator or otherwise.
Finally, the vapours, brought by the analyser to the desired degree of concentration
but without undergoing any supplementary condensation, escape through the pipe H,

page_text: going either to the ordinary refrigerator or otherwise where the alcohol undergoes a
final classification, permitting of the elimination of the last impurities brought over.
So long as the regulating refrigerator can be maintained at 80 or 81° °C, without
diminution of the supply of alcohol to the refrigerator, this process is kept up.
It becomes troublesome when the liquid from the boiler is so diluted as only to be
able to boil at 96° under the normal pressure.
At this moment, if there is a bad flavour rectifier, the contents of the boiler are
poured into it. Otherwise the admission of water into the tubes of the regulating
refrigerator is gradually diminished, in order to let the temperature of the latter rise,
and the middling tail flavours are collected in the ordinary way, then the bad
flavours and lastly the weak liquors.
This phase of exhaustion is very rapid, because the reserve of alcohol contained in
the column is almost null, and the column is protected from radiation.
Dated this 15th day of January 1889.
CARPMAEL & Co.,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Treatment of Commercial Alcohols.
I, HUGUES ERNEST SOREL, ex-Engineer of State Manufactures, residing at
No. 59ter Rue Buonaparte, Paris, in the Republic of France, do hereby declare the
nature of this invention and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement, reference
being had to the drawings left with the provisional specification and to Figure 7 left
herewith-
In the rectification or dephlegmation apparatus with trays or with balls, used in
the concentration or purification of alcohol or similar products, the practice is to
create, by means of a special appliance, "the analyser," a considerable reflux of
highly concentrated liquid at the top of the column in order to check the appear-
ance of the slightly volatile compounds which characterise the products called tail-
products.
This reflux envolves a very considerable increase in the cost of fuel, inasmuch
as all the liquid brought back by retrogradation into the column has to be evapo-
rated afresh.
As it is difficult to alter the heat surface of the apparatus, the productive
capacity of this apparatus is therefore diminished when the retrogradation is
increased.
Now the reflux only has the result of lowering the temperature of the stages of
the column and plays no other part. Its absolute quantity is not therefore to be
considered, if we can act in another way on the temperature of the column.
I have moreover observed that the object aimed at is not indeed fully attained
by the use of this costly process, and that by adopting the improvement hereinafter
described the appearance of the tail products can be still more retarded and in a
more economical fashion.
But first of all I will give a few theoretical indications, so as not to have to
revert thereto in the technical description.
The volatile impurities, without chemical action on the alcohol, contained in the
alcoholic vapours, are divided, at each stage of the dephlegmnation or rectification
column, between the non-condensed vapours which traverse that stage and the liquids
which arise from the condensation in the upper stages. For each temperature, there
is a fixed proportion between the quantity of a given impurity contained in a kilo-
gram of vapours and the quantity of the same impurity contained in a kilogram of the
liquids in contact with those vapours.

page_text: If therefore, we suppose a section of the column such that the temperature is
appreciably uniform from top to bottom, we shall have the equation:
P
in which 3, represents the proportion of impurity in the upper stage, sm the proportion
of the same inpurity in the lowest stage, m the number of stages, K the partage co-
efficient of the impurity between the vapours and the liquid, p the weight of the
vapours traversing each stage in an unit of time, and P the weight of the liquids
traversing it in an unit of time.
Thus the proportion of s₁ to sm: or, if you like the velocity of conveyance of the
impuritios from the bottom to the top of the column, does not depend on K, nor
on p, nor on P, taken each separately, but rather on the proportion K
of stages being always supposed to be the same.
the number
Now, I have ascertained, this new fact, that the proportion f is almost independent
of the absolute value of the reflux returning into the top of the column, and only
depends essentially on the temperature of the section considered. This proportion,
very low in the vicinity of 95 to 100° C, increases very rapidly when the temperaturo
decreases, attains its maximum when the temperature is between 80 and 82° C, and
then decreases with tremendous rapidity as soon as the temperature is below 80° C.
Thus at 79° C, it is four times less than at 83° C.
On the other hand, in proportion as the temperature decreases, the partage co-
efficient K diminishes, both because the tension of tho vapours diminishes, and because
the concentration of the alcohol, and therefore its dissolving power, increases.
To sum up, the term Kf increases in spite of the diminution of K from 90° ()
down to 80 or $2° C and then decreases very rapidly from that limit down to 78°-7
the point of ebullition of the most highly concentrated alcohol produced in industrial
apparatus.
The smaller this torm is the longer will the tail impurities he retained in the lower
parts of the column and consequently the greater will be the yield of "heart
alcohol."
There is therefore a considerable advantage in lowering the temperature of the
lower stages of the dephlegmation or rectification column, so that throughout the
whole of the column the term K 1 shall be as small as possible, in order to retard or
retain the tail products.
On the other hand, provided that the alcoholic vapours to be dephlegmated are
submitted to progressive refrigeration and that the condensed liquid be sent back into
contact with the vapours coming out of the distilling or rectifying boiler the cost of
fuel for one and the same concentration is independent of the manner in which the
refrigeration is effected provided that such refrigeration is strictly confined to pro-
ducing one concentration.
It is important to observe that the stages where the temperature ranges from 80°
to 81° C serve to mark off the part of the column in which the tail impurities are
constantly retained and turned back towards the bottom and the part in which they
iend to rise relatively faster than the alcohol.
This region is that which necessarily is most charged with this sort of impurities;
which there accumulate until the upper stages become incapable of retaining them.
It will in consequence be well to provide at this level for a suitable withdrawal of

page_text: such a way that those of one series correspond to the intervals of the series imme-
diately beneath and of the series immediately above. Their surface is plaited or
undulated in such a way that the condensed liquids are obliged to distribute thom-
selves regularly over all the cylinders of the section D.
The water first of all traverses the first upper series, then the second and so on, in
order to refrigerate the vapours methodically and bring them as economically as
possible to the required temperature. I of course reserve it to myself to add cold
water to the warm water supplied by the analyser,
if necessary.
The workman ascertains that the refrigeration is suitable, either by consulting a
thermometer placed in the current of the vapours underneath the grating bb, or better,
by observing the degree of the alcohol condensed in the refrigerator 1, fed by the in-
take c, placed underneath the said grating. This alcohol flows continuously, enclosed
from the air, into the testing glass J, into which an alcohol gauge and a thermometer
dip, and it is brought back to the column by the little tube d forming an hydraulic
joint.
After passing through the grating b b the vapours enter the dephlegmation column
properly so called, F, which is furnished with the same kind of stack as the section D
and surrounded by an insulating jacket. Then they reach the analyser G, composed
of a group of horizontal plaited or undulated tubes, similar to that which exists in E.
These tubes are traversed from the upper stage to the lower stage, by the warm
water coming either from the ordinary refrigerator or from the hot condensers described
in my previous Patent No. 1733888.
Finally, the vapours, brought by the analyser to the desired degree of concentration
but without undergoing any supplementary condensation, escape through the pipe H,
going either to the ordinary refrigerator or to successive condensers where the alcohol
undergoes a final classification, permitting of the elimination of the last impurities
brought over.
The extraction of alcohol overcharged with bad flavours from below the refri-
gerator can be effected as is indicated in Figure 7 by the interposition of a series of
parallel troughs m terminating in a collector which brings together the droppings
collected in the troughs so that they may escape by the inverted syphon o forming a
hydraulic joint.
represent 1 of the transverse section of
can be turned at will around axes 9.9
axis passing through the side of the
The series of troughs m and the collector n
the column. Plates pp controlled by a rod
by means of a crank s mounted upon an
column.
In the position represented the plates lead to the troughs a part of the droppings
from the refrigerator which, without their interposition, would pass freely down to
the stack D and so the quantity drawn off is increased. In the reverse position the
plates will reject from the troughs a part of the liquids which they would have
received. Thus, by means of the handles the regulation of the extraction of tail
alcohol charged with bad flavours may be effected at will according to the indication
of a suitable tell-tale placed in connection with the upper stages of the column.
So long as the regulating refrigerator can be maintained at 80 or 81° C, without
diminution of the supply of alcohol to the refrigerator, the process is continued as
above described.
It becomes troublesome when the liquid from the boiler is so diluted as only to be
able to boil at 96° under the normal pressure.
At this moment, if there is a bad flavour rectifier, the contents of the boiler are
transferred to it. Otherwise the admission of water into the tubes of the regulating
refrigerator is gradually diminished in order to let the temperature of the latter rise,
and the middling tail flavours are collected in the ordinary way, then the bad flavours
and lastly the weak liquors.
This phase of exhaustion is very rapid, because the reserve of alcobol contained in
the column is almost null, and the column is protected from radiation.

page_text: my said
Having now particularly described and ascertained the nature of
invention and in what manner the same is to be performed I declare that what I
claim is :-
1. The improvement in rectification or dephlegmation columns for the treatment of
commercial alcohols consisting in adapting at the lower part thereof a rei.igerating
apparatus substantially as described.
2. In combination with refrigerating apparatus applied as aforesaid, provision for
the continuous withdrawal of impure alcohol substantially as described.
3. The method of and the apparatus for the treatment of commercial alcohols sub-
stantially as described.
Dated this 8th day of October 1889.