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Патент USA US2408640

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0d- 1, 1946-
v
Q K. cu D. HICKMAN
'
‘2,403,639
VACUUM DISTILLATION PROCESS AND APPARATUS
Filed June 20, 1944
'
‘2 Sheets-Sheet 1
42'
KENNETH C.D. HICIQVAN
‘
'
INVENTOR
NW“
A 'ITORNE YS
Oct- 1, 1946- '
K. c. ‘D. HICKMAN
2,408,539
VACUUM DISTILLATION PROCESS AND APPARATUS
Filed June 20, 1944
74
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2 Sheets-Sheet 2
FIG. 3. .
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FIG.4.
KENNETH C.D.HICMN
184
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_
INVENTOR
98
v BYWW
‘ COOLING FLUID
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(gnu-‘M
ATTORNEYS
Patented Oct. 1, 1946
2,408,639
vumrrrzp I STATES PATENT OFFICE
vacuum msmm'non
maas'rusmocnss m I
Kenneth C. D. Hickman, Rochester, N. vit. assign
I or to Distillation
Products, Inc.,
N. Y., a corporation of Delaware
Application June 20, 1944, ‘Serial No. 541,253
11 Claims. (clan-52)
This invention relates to improved process and
vapparatus for vacuum distillation of thermally
decomposable substances while in the form of a
thin film.
~
under conditions such that it can start to distill
as soon‘as it reaches distillation temperature.
In the following description I have given several
1
of the preferred embodiments of my invention but
It is well known in the vacuum distillation art
vit is to be understood that these are set forth
for the purpose of illustration and not in limita
to subject thermally decomposable substances to
vacuum distillation while in the form of a thin
tion thereof.
film. The decomposable distilland is heated only
for the short period of time required during ?ow
'
In the accompanying drawings wherein like
numbers refer to like parts, I have illustrated sev
over the vaporizing surface in a thin ?lm. The 10 eral
of the preferred embodiments of my inven
undistilled residue can then belcooled and, if
tion wherein:
desired, the heat content thereof used to preheat I
‘ Fig. P1 is a vertical section of an improved grav
the fresh distilland ?owing into the still. ‘One of
the problems in the employment of such stills is
ity ?ow'still embodying the features of my in
bringing the distilland to distillation temperature 15
and rapidly cooling the‘ undistilled residue using '
some system of heat exchange.
’ from mainly in that an auxiliary external heater
for economy and to diminish to a minimum the
period of time in which the distilland is main
tained at a high temperature. The problem in 20
centrifugal vacuum stills, and to a lesser extent in
gravity ?ow thin film vacuum stills, is aggravated
by structural limitations. Thus, in the centrif
ugal vacuum stills it is inconvenient to heat or
‘
Consequently I a
heat exchangers are placed outside'the casing.
This means that hot liquid has to be piped for
} ,
Fig. 2 is a vertical section of a gravity ?ow still
similar to that illustrated in Fig. 1 differing there
This is required -
cool the distilland inside the still.
vention;
is used to heat the main portion of the vaporiz
ing surface of the still; '
I
‘Fig. 3 is a vertical section of a centrifugal still
provided with improved heat interchange in ac
cordance with my invention:
'
a
Fig. 4 is a modi?ed centrifugal ‘vacuum still
25
'provided with a steep conical vaporizing surface,
internal condensing surfaces and heat inter
change
and:
'
'
.
Fig. 5 is a section taken on line 5-5 of Fig. 4.
relatively long distances and the hot pipes must
Referring tovFig. 1, numeral I O‘designates a
often pass through the relatively co'ld walls of the
?at,
base plate integral with a cylinder I!
casing. The ultimate exchange of heat is poor 30 whichrigid
cylinder is closed at the top by a plate I‘.
and thermal decomposition due to unavoidably
Numeral l6 designates a cylinder serving as a still
~ long times of heating is increased.
casing which is positioned on plate Ill so as to be
This invention has for its object to avoid the
substantially concentric with cylinder l2. Nu
foregoing di?iculties. Another object of my in
meral l8 indicates a gas-tight end plate integral
vention is to provide improved vacuum distilla 35 with
cylinder l6. Numeral 20 designates a gas
tion process and apparatus whereby e?icient heat
ket serving to form a gas-tight joint between plate
interchange in a vacuum thin ?lm still is brought
It andi?ange 22 of cylinder l8. Numeral 24 des
about without substantial thermal decomposition.
ignates a conduit connectedto evacuating pumps 7
A further object is to provide improved high-vac
(not shown). Numeral 28 designates an annular
uum unobstructed path distillation process and 40 collar mounted upon the inside wall of casing is.
apparatus, particularly improved with respect to
Numeral 28 designates a conduit connected to the
heat losses and thermal ‘decomposition. Another
gutter formed by collar Y26 and easing l6. Nu
object is to improve the state of the art. Other
meral I0 designates a conduit serving towith
objects will appear hereinafter.
draw liquid collecting on the upper part of base '
These and other objects are accomplished by 45 plate Ill. Numeral 32 indicates a conduit for in
troducing liquid onto the top of plate i4.
my invention which includes vacuum distillation
Numeral 34 designates a coiled pipe which
process and apparatus wherein a thermally de
makes e?icient thermal contact with the upper in
composable organic substance is subjected to dis
t?lation under vacuum while in the form of a 50 side wall of cylinder II. This can be accomplished
:by soldering or welding. Numeral 36 designates a
thin film, heat is recovered from the residue and
similar coil which is similarly mounted upon the
the recovered heat is transferred to the incoming
decomposable organic substance while it is dis
lower inside wall of cylinder l2. ’ Numeral 38 des
ignates a conduit which connects coil 36 with
film. Theorganic substance is thus preheated 65 coil I4.» Numeral 40 designates a conduit‘which
connects the top part of coil N to the intake of
posed in the vacuum still in the form of a thin
2,408,639
3
.
4
circulating pump 42. Numeral 44 designates a
conduit connecting the exhaust side of the pump
42 to the lower portion of coil 36.
Referring to Fig. 2 numeral 50 designates a cen
tral coil making eilicient thermal contact with
the central inside wall of cylinder I2. The upper
end of this coil connects to the lower end of coil
turn is rigidly fastened to the lower portion of
by a burner 58. Numeral 80 designates a conduit
gutter I48. Numeral I50 designates a conduit for
introducing distilland onto the inside upper wall
cone I32 by ?ange I40 as illustrated. Plate I38
is provided with a number of holes I42 while the
upper portion of cone I32 is provided with a
number of perforations I44 to permit the egress
of gases. Flange I40 is provided with a plurality
of spacers so as to permit'liquid accumulating in
side cone I32 to pass between the two elements
38 while the lower end of this coil connects to a
of the flange and into gutter I46. Numeral I48
conduit 52 which leads to an external heating
coil 54 surrounded by a furnace 56 and heated 10 designates a conduit for withdrawing liquid from
which connects the upper portion'of coil 36 to
the lower portion of external heating coil 54.
Referring to Fig. 3, numerals 1'0 and 12 desig
nate respectively a base plate and a drum-shaped
cover which cooperate to form a gas-tight casing
for a centrifugal vacuum still of well-known type.
of cone I32. Numerals I52 and I54 designate
heat-exchange coils upon the inside upper and
lower walls of conical element I32 respectively.
These 'coils are connected together and to cir
culating pump 98 as previously described.
Numerals I56, I58 and I60 designate superim
Numeral 14 designates evacuating conduits lead
posed cylindrical condensing surfaces positioned
ing evacuating pumps (not shown). Numeral 18
designates an annular gutter integral with the 20 inside cone i52. These surfaces are stationary
and are provided at the lower edge of each with
upper portion of 12 to which is connected a with
gutters I62, I64 and I68 respectively. These con
drawal conduit 18. Numeral 80 designates a cir- ‘
densing surfaces are cooled by means of internal
cular, shallow cone-shaped vaporizing surface ro
cooling coils I68, I10, and I12 through which
tatably mounted upon shaft 82 which is rigidly
cooling ?uid is circulated by introduction
held in the position shown by bearings 84. The
through conduit I14 and withdrawal through
shaft passes through the base plate ‘10 and is pro
conduit i16. Condensate collecting in gutters
vided with a gas-tight packed gland 86. Numeral
362, I64 and I66 is withdrawn respectively
88 designates an annular gutter into which the
through conduits I18, I80 and I82.
periphery of vaporizing plate 80 extends. Nu
Numeral I84 designates a gear integral with
meral 90 designates a withdrawal conduit con 30
the
outwardly turned lip of plate I38. The gear
nected to gutter B8.
is driven by driving gear I86, which is in turn
Numeral 92 designates a helical coil integral
driven by shaft I88, which passes through packed
with the central part of plate 80 and making effi
gland I90.
cient thermal contact therewith. Numeral 94
In operating the apparatus illustrated in Fig.
designates a helical coil of larger diameter than 35
l, the still is evacuated by means‘ of pumps con
coil 92 and integral with the outside portion, of
nected to conduit 24. Liquid to be distilled is in
plate 80. Numeral 96 designates a conduit con
troduced through conduit 32. Heating element
necting the inside end of coil 92 to the intake of
comprising an electrical resistance wire II is put
pump 98. Numeral 91 designates a reservoir or
into operation and circulating pump 42 is started.
expansion chamber for extra heat exchange liq
Distilland collects on plate I4, flows over the up
uid which is connected to the intake of pump 98
per edge of I2 and downward in a thin ?lm on
by conduit 99 which gradually increases in dis
the outside surface of I2. When this thin ?lm
tance from shaft 82 as it passes from reservoir 91
reaches the area heated by heater II it is par
to the intake of pump 98. Numeral I00 desig
tially distilled. . The vapors thus formed con
nates a conduit connecting the other end of coil
dense on the inside wall of outer casing I6, flow
92 with the inside end of coil 94. Numeral I02
by gravity into gutter 26 and are withdrawn
designates a conduit which connects the outside
through conduit‘ 28. The hot undistilled residue
end of coil 94 with the intake of pump 98. Nu
on column I2 then flows in a thin film over the
meral I04 designates a conduit for introducing
distilland onto the center of vaporizing plate 80, 50 lower portion of column I2 opposite heat recov
while numeral I06 indicates an electrical resist
ance wire for heating the center portion of va
porizing plate 80, the heat being re?ected toward
plate 80 by re?ector I08. Numeral IIO designates
a stationary gear rigidly mounted upon support
H2 so as to engage with gear II4 which drives
pump 98.
Referring to Figs. 4 and 5 numeral I20 desig
nates a rigid base plate upon which is mounted
gas-tight conical still casing I22 which is pro
vided with an evacuating conduit I24. Casing
I22 is provided with a gas-tight cover or end
plate I26 through which passes a stationary hol
low shaft I28 which is rigidly mounted in the po
sition shown by being integrally fastened to sup
I port I30 and to base plate I20. Numeral I32 des
ignates a cone of about the same shape as casing
I22 but of smaller diameter which is rigid but ro
‘tatably mounted in the position shown by means
of bearings I34 and I36. The innerhalf of bear
ings I34 and I36 are‘mounted upon the wall of
shaft I28 in a stationary manner. The outer half
of bearing I34 is integral with the upper wall of
ery coil 36. A heat transfer liquid such as di
phenyl or “Dowtherm” in coil 36 is then heated
to an elevated temperature. This hot liquid then
flows upwardly through conduit 38 and preheat
ing coil 34 due to the action of circulating pump
42. The distilland as it flows in a thin film over
the upward portion of column I2 is thus pre
heated while it is subjected to the vacuum dis
tillation conditions. If the liquid should be pre
heated to distillation temperature while still on
the area of the preheater, it could distill and no
unusual thermal decomposition, therefore, would
take place. The cool heat transfer agent is then
circulated downward through conduit 40 and cir
culating pump 42 and is again passed through
the heat-recovery coil 36. These operations are
repeated throughout the distillation process.
Undistilled residue accumulates on the upper sur
face of I0 and is withdrawn through conduit 30.
In operating the apparatus illustrated in Fig. 2,
the still is put into operation the same as de
scribed in Fig. 1. Burner 58 is put into operation.
The heat-exchange fluid is then circulated by
pump 42.‘ The ?uid ?rst passes through coil 36
rotating conical element I32 while the outer half
of bearing I36 is integral with plate I38, which in 75 where it picks up heat from the undistilled resi
2,‘08,089
due on the lower outside wallof cylinder I2. This.
partially heated ?uid then passes through con
duit 80 into heater coil “where it is further
heated. It then passes through conduit 52 into
heater coil 50 where it heats the central portion
of cylinder I2 to distillation temperature. The
inside surface of I82 are condensed upon the
cool outer surfaces of cylinders I88, I58, and I80.
Three fractions are separated on these surfaces.
These fractions ?ow by gravity respectively into
conduits I82, I84, and I88, and are withdrawn
respectively through withdrawal conduits I18,
liquid is partially cooled by giving up some of its
I80, and I82.
heat content to the distilland and this partially
My invention is of particular importance in
cooled heat-exchange liquid then ?ows through
connection with the preheating of thermally de
coil 84 where it partially preheats the distilland 10 composable substances while in a thin ?lm and
at the top of cylinder I2. The cool heat-exchange
while under vacuum distillation conditions. The
liquid then is returned through the cycle by cir
similar
treatment of the undistilled residue, 1. e.,
culating pump 42.
while it is in the form of a thin ?lm and under
In operating the apparatus illustrated in Fig. 3,
vacuum conditions is important only where it is
shaft 82 is caused to rotate by force applied out 15 to be further distilled to recoverthermally cle
side of the still. Liquid to be distilled is intro
composable substances. Obviously if all the de
duced through conduit I04 onto the center of
rotating plate 80. The system is evacuated
through conduits 14 and the vaporizing surface
80 is heated to distillation temperature in the
central portion thereof by heater I08. The dis
tilland is caused to ?ow from the center to‘ the
periphery of 80 in the form of a thin ?lm. Dur
ing passage over the central portion it is heated
to distillation temperature by heater I08.
Va
pors given oil’ are condensed on the upper wall,
composable substances have been recovered there
from or it is not to be further distilled it is not
important to avoid thermal decomposition or
to handle the undistilled residue carefully.
Thereforé, it is to be understood that my inven
tion is applicable in such cases only to the pre
heating step and that the residue may be col»
lected and heat regeneration accomplished in any
manner so long as the regenerated heat is circu
lated back to the incoming distilland while it is
?ow by gravity into gutter ‘I8, and are with
in the form of a thin ?lm and under vacuum con
drawn from the still through conduit 18. Un
ditions.
distilled residue is thrown from the periphery of
What I claim is:
80 into gutter 88 and is withdrawn through con 30
1. High-vacuum distillation apparatus com~
duit 90. Coils 82 and 94, contain heat-exchange
prising in combination a vaporizing surface, a
liquid. During rotation pump 88 rotates with
condensing surface, means for heating the va
plate 80. Since gear H8 is stationary, gear H4
porizing surface, means for distributing distilland
is caused to rotate and this actuates pump 88.
onto the vaporizing surface in a thin ?lm, means
Heat-exchange liquid is caused to ?ow by the 35 for removing undistilled residue from the va
action of the pump 88 from coil 94 into coil 92
porizing surface, means for recovering heat from
and thence by way of conduit I00 back into coil
the undistilled residue while it remains in the
84. Heat is taken up from the undistilled residue
form of a thin ?lm in the still, means for trans
by coil 94 and is conveyed to coil 82 where the
ferring this recovered heat to the incoming dis
heat is given up to the distilland when it is ?rst 40 tilland while it is in the still, while it is in the
introduced onto the vaporizing plate 80 in order
form of a, thin ?lm and immediately previous to
to preheat it, The distilland is thus preheated
its passage onto the vaporizing surface, and
while subjected to the vacuum and while it can
distill as soon as it becomes preheated to distilla
means for removing condensate from the con
densing surface.
tion temperature. There is, therefore, no lag 45 2. High-vacuum distillation apparatus com
between preheating and distillation.
prising in combination a vaporizing surface, a
In operating the apparatus illustrated in Figs,
condensing ‘surface, means for heating the va
4 and 5, the system is evacuated through con
porizing surface, means for distributing distilland
duit I24. Cone ‘I32 and integral pump 88 and
onto the vaporizing surface in a thin ?lm, means
heat-exchange coils I52 and I54, are rotated as 50 for removing undistilled residue from the vapor
an integral unit by force applied through shaft
I88, gear I88 and gear I84. Liquid to be dis
tilled is introduced through conduit I58 onto the
izing surface, means for recovering heat from the
undistilled residue, means for transferring this
recovered heat to the incoming distilland while
inside upper surface I32. The liquid flows in a
it is in the still, while it is in the form of a thin
thin ?lm by a combination of gravitational and 65 ?lm while it is exposed to the high vacuum in
centrifugal force to the bottom of cone I32, and
the still and immediately previous to its passage
is then thrown between the elements of ?ange
onto the vaporizing surface in the form of a thin
I40 into gutter I48, and is withdrawn as undis
?lm, and means for removing condensate from
tilled residue through conduit I48. Gases pres
the condensing surface.
ent in the distillation chamber,.i. e., gases inside 60
3. High-vacuum unobstructed path distillation
cone I32, pass through holes I 42 ‘at the base and
apparatus comprising in combination a vaporiz
perforations I44 at the top are then withdrawn
ing surface, a condensing surface, separated from
,
the vaporizing surface by substantially unob
Undistilled residue heats coil I54, as previously
structed space, means for heating the vaporizing
explained. This coil contains heat-exchange ?uid 65 surface, means for distributing distilland on the
which then is forced by circulating pump 88 up
vaporizing surface in a thin ?lm, means for re
into preheating coil I 52, where the distilland is
moving
undistilled residue from the vaporizing
preheated. The somewhat cool heat-exchange
surface, means for recovering heat from the un
?uid is then returned by circulating pump 88
distilled residue while it remains in the form of
to coil I54 as previously described. The central 70 a thin ?lm in the still, means for transferring
portion of vaporizing surface I32 is heated by
this recovered heat to the incoming distilland
electrical coil I08 and re?ector I08 as described
while it is in the form of a thin ?lm in the still,
in connection with Fig. 3.
and‘ immediately previous to its passage onto the
Cooling ?uid is circulated through coils I68,
vaporizing surface, and means for removing con
I10 and I12. Therefore, vapors generated on the 75 densate from the condensing surface.
through conduit I24. '
2,408,689
8
surface. means constituting a continuation of the
vaporizing surface for recovering heat from the
undistilled residue while it is in the form of a
ing surface, a condensing surface separated from
thin ?lm and while it is exposed to the vacuum
the vaporizing surface by substantially unob
conditions prevailing in the still, means constitut
structed space, means for heating the vaporizing GI ing
a preheating portion of the vaporizing sur
surface, means for distributing distilland onto
face
for transferring this recovered heat to the
the vaporizing surface in a thin ?lm, means for
incoming distilland while the distilland is spread
removing undistilled residue from the vaporizing
thereon in the form of a thin ?lm, and while it
surface, means for recovering heat from the un-'
is exposed to the vacuum conditions prevailing
ii)
distilled residue while it remains in the form of a
in the still, and means for removing condensate
thin ?lm in. the still, means for transferring re
from the condensing surface.
covered heat to a liquid, means for conveying this
8. The process of high-vacuum distillation
heated liquid into thermal contact with the in
comprising subjecting an organic substance
coming distilland while it is in the form of a thin
?lm in the still and immediately previous to its 15 which tends to decompose at a temperature nec
essary for distillation to high-vacuum distillation
passage onto the vaporizing surface, and means
while in the form of a thin ?lm, recovering heat
for removing condensate from the condensing
from the undistilled residue while it remains in
surface.
the still, while it is exposed to the vacuum there
5. High-vacuum unobstructed path distillation
and while it is in the form of a thin ?lm, and
apparatus comprising in combination a vaporiz 20 in,
conveying the recovered heat to the incoming
ing surface adapted to cause distilland to ?ow
organic substance while it is in the form of a thin
thereover in a thin ?lm by centrifugal force, a
?lm and while it is exposed to the vacuum condi
condensing surface separated from the vaporizing
tions prevailing duringthe vacuum distillation.
surface by substantially unobstructed space,
9. The process of high-vacuum distillation
25
means for heating the vaporizing surface, means
, comprising subjecting a thin ?lm of an organic
for introducing distilland onto the vaporizing
substance which tends to decompose at a tem
surface, means for removing undistilled residue
perature necessary for distillation to high-vacu
4. High-vacuum unobstructed path distillation
apparatus comprising in combination a. vaporiz
from the vaporizing surface, means for recover
ing heat from the undistilled residue while it re
um distillation by causing it to ?ow over a heated
vaporizing surface in the form of a thin ?lm, re
mains in the form ofa thin ?lm in the still and 30 covering heat from the undistilled residue as it
for transferring it to a liquid, means for adding
?ows in a thin ?lm over the last part of the va
additional heat to this partially heated liquid,
means for circulating this heated liquid into
thermal contact with the vaporizing surface and
then into thermal contact with incoming dis
porizing surface and conveying the recovered
heat to the incoming organic substance while it
tilland while it is in the form of a thin ?lm in
10. The process of high-vacuum distillation
comprising subjecting a thin ?lm of an organic
the still and immediately previous to its passage
onto the vaporizing surface, and means for re
moving condensate from the condensing surface.
is in the form of a thin ?lm on the ?rst part of
the vaporizing surface.
_ -
substance which tends to decompose at a tem
perature necessary for distillation to high-vacu
40
6. High-vacuum unobstructed path distillation
um distillation by causing it to ‘?ow over a heated
apparatus comprising in combination a vaporiz
ing surface adapted to cause distilland to ?ow
thereover in a thin ?lm by centrifugal force, a
condensing surface separated from the vaporizing
surface by substantially unobstructed space,
means for introducing distilland onto the vapor
izing surface, means for removing undistilled
residue from the vaporizing surface, means for
recovering heat from the undistilled residue while
it remains in the form of a thin ?lm 0n the out
ermost part of the centrifugal vaporizing surface,
vaporizing surface in the form of a thin ?lm,
recovering heat from the undistilled residue, con
veying the recovered heat to the incoming or
ganic substance while it is in the form of a thin
?lm within the still and while it is exposed to the
high vacuum in the still and then immediately
heating this preheated thin ?lm to distillation
temperature.
11. The process of high-vacuum distillation
comprising subjecting an organic substance which
tends to decompose at a temperature necessary
means for transferring this recovered heat to the
for distillation to high-vacuum distillation by
incoming distilland while it is in the form of a
causing it to ?ow in the form of a thin ?lm by
thin ?lm on the innermost part of the centrifugal
centrifugal force over a heated vaporizing sur
55
vaporizing surface, and means for removing con
face, recovering heat from the undistilled residue
densate from the condensing surface.
at the outermost portion of the vaporizing sur
7. High-vacuum unobstructed path distillation
face
and while the undistilled residue from which
apparatus comprising in combination a vaporiz
the heat is recovered is still in the form of a thin
ing surface, a condensing surface separated from
and conveying this recovered heat to the
the vaporizing surface by substantially unob 60 ?lm,
innermost portion of the centrifugal surface upon
structed space, means for heating the vaporizing
which the incoming distilland is disposed in the
surface, means for distributing distilland onto
the vaporizing surface in a thin ?lm, means for
removing undistilled residue from the vaporizing
form of a thin ?lm by centrifugal force.
KENNETH C. D. HICKMAN.
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