separating liquids having different boiling points
Year: 1888

page_text: 1, JAMES YATE JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex,
Gentleman do hereby declare the nature of this Invention which has been com-
municated to me from Abroad by La Société Francaise des alcools purs of Paris in
the Republic of France to be as follows:-
This Invention relates to apparatus for separating liquids having different boiling
points. Apparatus performing this operation according to the present Invention
comprises a boiler containing the liquid and provided with means for applying
heat and a surface condenser so arranged that no part of the vapours from the
boiler can pass through it without coming into contact with surfaces which are
maintained at such a temperature that the vapours of those liquids that are to be
eliminated cannot be condensed upon them whilst the liquids that are to remain are
completely condensed.
By means of apparatus combined and operating as hereinafter described the
operation is enabled to be conducted in a continuous manner and by means of the
heat regenerating arrangements the cost is reduced to a minimum.
The apparatus may be employed with advantage in all cases where it is necessary
to separate liquids having different boiling points such as the separation of the ethylic
alcohol, aldehydes and other of the more volatile products contained in crude alcohol
for example.
The crude alcohol or other liquid to be treated in the apparatus undergoes a
preliminary heating in a worm or tubular regenerative apparatus where it is heated by
waste heat before entering the boiler and at the same time cools the liquids which
have passed through the apparatus. The liquids after this preliminary heating are
conducted to the top plate in an apparatus in the form of a column being provided
with a series of plates or heated surfaces which the liquid is caused to pass over in
succession before reaching the boiler. In descending over these plates or surfaces the
liquid is heated and partially evaporated the extent of surface over which it has to

page_text: travel and the degree of heat to which it is exposed being regulated according to the
effect to be produced. The plates may be hollow and be heated by steam or hot air
or water or any other agent or they may be combined with coils of flattened tubes or
steam or water pipes
According to another method the liquid on each plate may be heated by the vapours
rising from the plate next beneath it the said vapours being caused to bubble through
the liquid for example.
In order that the accidental introduction of cold liquid on to the top plate of the
evaporating apparatus may not be liable to affect the action of the apparatus by
choking or clogging the parts in consequence of sudden condensation of the vapour
the top plate is constructed with tubes heated internally by the vapours from the
plate beneath and serving to heat the liquid entering the apparatus without coming
into direct contact therewith.
As the liquid passes through this apparatus the more volatile parts are gradually
evaporated at a rate which depends on the construction and arrangement of the
apparatus and is completely separated from the volatile products to be eliminated. On
leaving the boiler the boiling liquid is conducted to a tubular regenerator where it is
cooled and at the same time utilized for heating the liquid entering the apparatus.
The cooling of the liquid from the boiler may be completed by any suitable refrigerating
apparatus.
The evaporator may be arranged either vertically or horizontally and may be
provided with means for separately removing the different products For example a
series of boilers may be employed being connected by siphons or other suitable
arrangements or one boiler may be divided into a number of separate compartments
with means for enabling the liquid to flow from one to the other.
The vapours produced are conducted to an analyser or apparatus provided with con-
densing surfaces so arranged that it is impossible for any of the vapours to pass
through the analyser without coming into contact with these surfaces which act as
true analysers of the vapours letting some pass on and arresting or condensing others.
With this object the vapour is caused to circulate in narrow annular spaces between
concentric cylindrical or other surfaces and the temperature of these surfaces is regulated
according to the nature of the mixed vapours that it is desired to separate.
In separating ethy lic alcohol from the vapours of aldehyde or other more volatile
products for example it is evident that by maintaining the condensing surfaces at a
temperature of about 65 and under 75 degrees Centigrade all the alcoholic vapours
will be condensed in the analyser whilst the vapours of liquids such as ethylic, aldehyde,
acetone and the like whose boiling point is above 70 degrees Centigrade will pass on
to be separately condensed in a suitable refrigerator. Any vapours that are not con-
densed in the refrigerator can be discharged or absorbed.
The liquids of condensation are returned by a siphon or otherwise to the evaporator
or to an apparatus where the vapours escaping from the action of the analyser are
separately collected and are condensed by a tubular condenser or worm whence they
flow into a special vessel whence the liquid can be taken for being treated separately
the alcohol for example being separated on one hand, the aldehyde and other volatile
products on the other by any suitable means
It is necessary to maintain the surfaces in the analyser at the proper temperature
for example in treating the alcoholic products herein before referred to the most
advantageous temperature for the upper part is about 65 degrees Centigrade and that
for the lower part must not exceed about 75 degrees. It results that the water entering
at the upper part of the analyser at a temperature of about 65 degrees escapes at the
lower part at about 75 and to bring it into condition to be re-used it is simply
necessary to lower its temperature by about ten degrees. This may be done by any
convenient arrangement such as causing the water to pass through a tubular or other
surface refrigerator the cooling water being utilized for feeding steam boilers for
example but it is preferable to obtain the desired result by mixing the hot water
discharged from the analyser with a certain quantity of cold water the mixture being
ensured by causing the water to pass through a vessel provided with baffle plates or

page_text: other equivalent arrangement and a centrifugal or other pump being employed to
draw water from the mixing vessel and deliver it at the top of the analyser. A
thermometer placed in communication with the pipe enables the temperature of the
water to be regulated with precision by increasing or diminishing the quantity of cold
water employed.
The analyser is provided with a suitable arrangement of tubes or pipes for the
passage of the cooling water and of the vapours combined with concentric or other
cooling surfaces formed by combinations of large and small tubes for example on
which the vapours are partially condensed the uncondensed portion being separately
condensed in another apparatus In place of the analyser with concentric cylindrical
or tubular surfaces analysers with coiled tubes or worms may be employed the tubes
being of a flattened shape in transverse section in order to compel the vapours to pass
in a thin stream and bring every part effectually into contact with the condensing
surface or surfaces.
D

page_text: COMPLETE SPECIFICATION.
Apparatus for Separating Liquids having Different Boiling Points.
I, JAMES YATE JOHNSON of 47 Lancolns Inn Fields in the County of Middlesex,
Gentleman do hereby declare the nature of this invention (which has been com-
municated to me from Abroad by La Société Francaise des alcools purs of Paris in
the Republic of France) and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement
•
This Invention relates to apparatus for separating liquids having different boiling
points. Apparatus performing this operation according to the present invention
comprises an evaporating apparatus in combination with a boiler and a surface con-
denser so arranged that no part of the vapours from the evaporator can pass through
it without coming in contact with surfaces which are maintained at such a temperature
that the vapours of those liquids that are to be eliminated cannot be condensed upon
them and pass on through the condenser whilst the liquids that are to remain are
completely condensed and retained.
By means of apparatus combined and operating as hereinafter described the
operation is enabled to be conducted in a continuous manner and by means of
regenerating arrangements the heat is greatly economised and the cost is reduced to a
minimum. The apparatus may be employed with advantage in separating any liquids
having different boiling points such as in the separation of ethylic alcohol, aldehydes
and other more volatile products contained in crude alcohol for example.
And in order that the said invention may be fully understood I shall now proceed
more particularly to describe the same and for that purpose shall refer to the several
figures in the annexed sheets of drawings the same letters of reference indicating
corresponding parts in all the figures.
Figure 1 of the accompanying drawings is a view in elevation shewing the general
arrangement of apparatus according to this invention arranged for treating backings
or feints for example.
Figure 2 shows the apparatus in plan and Figures 3 and 4 drawn to a larger scale,
represent respectively a part vertical section and a horizontal section of the analyser or
condenser, Figure 5 also drawn to a larger scale represents in vertical section a heating,
evaporating and heat regenerating apparatus hereinafter described. Figures 6, 7 and 8
illustrate modifications of the evaporating apparatus. The essential parts of this
apparatus consist of a boiler A Figures 1 and 5 an evaporating column Can analyser
or condenser B Figures 1, 3 and 4 and sundry accessory arrangements for ensuring
the continuous and economical action of the apparatus.
The evaporating of the liquid takes place in the cylindrical column C illustrated in
section in Figure 5. This column is placed immediately over a cylindrical boiler A
heated by a steam worm a supplied with steam from a pipe 2 and provided with an
overflow pipe leading to a heat regenerating chamber D likewise of cylindrical form
containing a worm c through which the feints or backings supplied to the apparatus
through a pipe 1 pass on their way to the evaporator and in which they undergo a

page_text: preliminary heating by the waste heat of the liquid overflowing from the boiler A
through the pipe b. At the same time this liquid from the boiler is cooled by trans-
ferring its heat to the said feints or backings entering the apparatus
The evaporating column C communicates directly with the boiler A and is provided
with a number of superposed discs or plates e over which the liquid is caused to flow
being conducted from the worm c hereinbefore described by a pipe t to the upper
part of the said evaporating column where it is received in a compartment closed at
the bottom by a plate d provided with a number of short tubes d' communicating with
the space beneath the plate d. The object of this arrangement is to enable the liquid
which is previously heated in the worm c to such an extent as to require but little
additional heat to bring it up to the boiling point to acquire the requisite temperature
to enable it to boil when it reaches the plates e underneath the plate d. This additional
heat is obtained from the vapour rising from the plates e which vapours pass upwards
through the pipes
d. The hot liquid above the plate & descends through an overflow
pipe on to the plate e next beneath the plate ď
d
The plates e can be constructed in various ways. Their functions are firstly to
retain the liquid in the apparatus for a sufficient time to enable those parts which are
more volatile than ethylic alcohol to be converted into vapour and secondly to enable
the liquids to be supplied with the heat necessary to produce this effect With these
objects the plates are best constructed as illustrated in Figure 5 presenting a flat
surface with a central hole surrounded on the upper side by a ring or rim in the form
of a truncated cone e¹ provided with two or more openings e³. These openings e² are
so arranged that firstly the openings e on each plate are not situated vertically over
the openings in the plate next below and secondly the lower edges of the openings
coincides with the level at which the liquid is to stand on the plates their object being
to enable the liquid to overflow from one plate to another. A coiled pipe supplied
with steam, hot water, or other heating agent is provided on each plate the steam or
the like being introduced at one side of the apparatus and passing off at the other by
means of a suitable combination of pipes as indicated in the drawing for example. In
place of supplying the coil on each plate separately the coils may be arranged in
groups of any suitable number of coils each group being supplied with the heating
agent at one side and discharging it on the other
It preferred the plates may be heated by causing the heating agent to circulate in a
double bottom formed in or under the plates as indicated in Figures 6 and 7 or the
vapours produced on each plate may suffice to heat the liquid on the plate next above
it the said vapours being caused to bubble through the liquid by means of an arrange-
ment such as that illustrated in Figure 8.
The upper part of the column C communicates through a pipe X Figures 1 and 2.
with a condensing apparatus or analyser B. This apparatus illustrated in elevation in
Figure 1 and in vertical and horizontal section in Figures 3 and 4 respectively must
comply with two conditions the first being that the condensing surfaces must be so
arranged as to render it impossible for any vapours to pass though the analyser
without coming into contact with these surfaces which act as true analysers of the
vapours permitting some or the more volatile to pass on and arresting or condensing
others or the less volatile. With this object the vapour is caused to circulate in
extremely narrow or contracted annular spaces between concentrically arranged
tubular or cylindrical surfaces.
The external surface of the inner tube and the internal surface of the outer tube
constitute two condensing surfaces which may be brought sufficiently near together to
ensure that by constructing the tube of sufficient length every molecule of vapour
passing between them shall be compelled to come in contact with one or the other
of the said surfaces. The second of the two said conditions is that the temperature of
the condensing surfaces must be capable of being regulated according to the nature
of the mixed vapours that it is desired to separate.
The analyser is arranged as hereinafter described with reference to Figures 3 and 4
for the purpose of obtaining an absolute equality of temperature at all parts of the
surfaces situated in the same horizontal plane or at any given level. The condensing

page_text: sui faces are constituted by a series of pairs of concentric tubes p and the tubes p
being arranged inside the tubes v with a narrow annular space f between the tubes p
and for the passage of the vapours that are to be condensed The inner tubes p
communicate at their lower extremities with a chamber 0 and at their upper
extremities with a chamber N The outer tubes communicate at their lower
extremities with a chamber M and at their upper extremities with a chamber G. The
intermediate space between the chambers M and G forms a chamber W occupying the
greater part of the interior of the analyser shown bioken away in figure 3 in order to
bring the figure within the limits allowed for the drawing
The
The feints or backings or crude alcohol to be treated in the apparatus undergo a
preliminary heating in the worm e in the regenerative apparatus D Figures 1 and 5
where it is heated by waste heat before entering the boiler A and at the same time
cools the heated liquids which have passed through the evaporating apparatus
liquids after this preliminary heating are conducted by the pipe t to the upper part of
the evaporating apparatus (in the form of a column provided with a series of
horizontal plates or partitions as herein before described. The impure alcohol heated
by heat absorbed from the purified feints issuing from the lower part of the apparatus
is caused to flow onto the upper plate (d) in this column and flows downwards over
the plates e passing from one plate to another until it reaches the boiler A. In
descending over the plates e the feints are heated to ebullition on each plate so that
they reach the boiler A after having given off vapours for a period corresponding to
the dimensions of the evaporator acting as a flow retarder and classifier and the
rate at which they are supplied. It is evident that, other things being equal the
supply must be smaller when the feints contain a fairly large quantity of aldehydes
and other foreign matter of a low boiling point and may be greater when the pro-
portion of these impurities is smaller.
It will be readily understood that as the liquid passes through this evaporating
apparatus it gradually separates from the more volatile parts at a rate which depends
on the construction and arrangement of the apparatus and on reaching the boiler at A
it is so sufficiently freed from the volatile products to be eliminated to enable the
boiling to which it is subjected in the said boiler to entirely remove any volatile
matter that yet remains in the liquid.
The boiling and purified liquid escapes from the boiler A through the overflow
pipe b Figure 5 to the tubular regenerator D where it is cooled and at the same time
utilised for heating the feints or impure liquid circulating in the worm c beneath the
boiler before entering the evaporator C This cooling process is completed by causing
the liquid to pass through a pipe 3 to a cooler I Figure 1 constructed with tubes or a
worm and in which the temperature of the feints is lowered to about 15 or 20 degrees
Centigrade after which they pass through an eprouvette or testing apparatus E into
suitable vessels or tanks.
The evaporator is represented in the drawing as being arranged vertically, this is
the most economical and convenient arrangement but is not essential.
Any other
arrangement capable of producing similar results may be employed the period occupied
by the liquid in passing through this part of the apparatus being regulated so as to
obtain a continuous action and secure the separation of the products according to the
degree of purification.
For example a series of boilers may be employed being arranged for the liquid to
gravitate from one to the other or being connected by siphons overflow pipes immersed
at the lower ends or other suitable arrangements, or one boiler may be divided into a
number or series of separate compartments provided with means for enabling the
liquid to flow from one to the other throughout the series. In all cases the crude
alcohol or impure feints are admitted at one extremity of the series of vessels or
compartments in which they are retarded and classified the purified feints or alcohols
being discharged at the other extremity.
The vapours ascending from the evaporating apparatus C (Figure 1) through the
pipe X enter the chamber M (Figure 3) and pass up the narrow annular spaces f
between the tubes p and where they are partly condensed the more volatile or

page_text: uncondensed portion passing into the chamber
pipe k to a refrigerator K (Figaros 1 and 2).
whence it is conducted through a
The water or other cooling agent at about 65 degrees Centigrade is supplied to the
analyser B by a pump s for example through a pipe S leading to branch pipes S1 S2 S
Figure 1 The branch pipes S₁ S² supply water to the chamber W in which it
circulates in contact with the outer surfaces of the tubes and the branch
pipe S³ conducts water to the chamber N communicating with the interior of the
tubes p.
The water supplied to the chamber N descends through the tubes p to the chamber O
whence it is discharged through a pipe at Q and the water supplied to the chamber W
escapes through branch pipes U U₁ communicating with a pipe U³. The heated
water discharged through the pipes and U³ is conducted to a cold water tank Z
Figure 1 where it is cooled by flowing under and over partitions provided in the
tank as indicated by the dotted lines
The liquid products of the condensation of the vapours between the concentric
walls of the tubes p and tickles down into the chamber M whence it is discharged
through a pipe at V Figure 3.
To facilitate the removal or renewal of the large tubes the tube plates p¹ and p²
supporting the small or inner tubes p are perforated with holes of sufficient
diameter for the passage of the large tubes and the tubes p are provided with
collars fitting into these large holes the said collars being preferably made of soft
bronze or alloy so that the pressure of the tubos p may be sufficient to wedge them in
the holes and make a tight joint
In the example taken for the sake of illustration the object is to separate from
ethylic alcohol the vapours of aldehyde or other more volatile products By allowing
for the difference between the boiling points of these products and the boiling point
of ethylic alcohol it is evident that by maintaining the condensing surfaces at a
temperature of about 65 or under 75 degrees Centigrade all or the greater part of
the alcoholic vapours entering the analyser will be condensed therein whilst the
vapours of liquids such as ethylic aldehyde, acetone and the like whose boiling point
is lower or under about 70 degrees Centigrade pass on and are finally condensed in
the refrigerating condenser K The products of this condensation flow into a special
vessel not shewn in the drawing from which the liquid can be drawn off for treatment
separately the alcohol for example being separated on one hand, the aldehyde and
other volatile products on the other by any suitable means. Any products not
condensed or liquefied in the apparatus K are conducted to an apparatus where they
are absorbed by any suitable liquid or are simply discharged into the atmosphere
The liquid products of the condensation in the analyser condenser B being
discharged at Vas hereinbefore described are collected in suitable vessels or may be
returned to the evaporating column to be evaporated again.
It is evident that the same apparatus may be employed for analysing or separating
any mixtures of vapours of liquids boiling at different temperatures under the same
conditions as regards economy and continuousness of action. For this purpose it is
simply necessary to modify the details of construction of the condensing surfaces in
the analyser according to the object in view.
It is necessary to maintain the surfaces in the analyser at the proper temperature
and the apparatus herein before described with reference to Figures 3 and 4 enables
this temperature to be regulated with great facility and precision for example in
treating the alcoholic products hereinbefore referred to the most advantageous
temperature for the upper part must be about 65 degrees Centigrade and that for the
lower part must not exceed about 75 degrees With this object the analyser B 18
supplied with cooling water entering at the upper part at a temperature of about
65 degrees and escaping at the lower part at about 75 and to bring this water and
cooling liquid into condition to be re-used it is simply necessary to lower its temperature
by about ten degrees. This may be done by any convenient arrangement such as one
in which the water is caused to pass through a tubular or other surface refrigerator
the cooling water from this apparatus boing utilised for feeding steam boilers for

page_text: example but it is preferable to obtain the desired result by mixing the hot water
discharged from the analyser with a certain quantity of cold water the mixture being
ensured by causing the water to pass through the vessel Z provided with baffle plates
as indicated in Figure 1 or other equivalent arrangement a centrifugal or other
being employed to draw the water from the mixing vessel Z through a pipe and
return it through the pipe S to the upper part of the analyser.
pump
A thermometer or thermometers placed in communication with the pipes enables
the temperature of the water to be regulated with precision by increasing or
diminishing the quantity of cold water employed in the cooler Z
Having now particularly described and ascertained the nature of the said Inven-
tion and in what manner the same is to be performed 1 declare that what I
claim is :-
1. In apparatus for separating liquids having different boiling points an evaporating
column C provided with heated plates or partitions or other equivalent evaporating
apparatus in which the liquids to be treated being pre-heated by the liquid escaping
from the boiler are separated from the more volatile products in combination with a
boiler A in which the process of separation of evaporation is completed and an analyser
or condenser B in which the vapours discharged from the boiling and evaporating
apparatus are condensed to a pre-determined extent by passing through a narrow or
contracted annular spaces maintained at a regulated temperature and formed by
concentric tubes all substantially as herein before described with reference to the
accompanying drawings.
2. The general combination and arrangement of parts constituting the improved
apparatus for separating liquids having different boiling points substantially as
hereinbefore described.