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A.> H.- RADASCH ET AL
2,075,866
TREATMENT OF TAR
Filed March 2l, 1934
5 sheets-'smet 1
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April 6, 1937-
_ A. H. _RADAscH ET AL
2,075,866
TREATMENT OF TAR
Filed March 2l, 1934 ,
5 Sheets-Sheet 2
`
ATTORNEY
April 6, 1937.
A. H. RA‘DASCH ET AL
TREATMENT OF TAR
Filed March 2l
1934
2,075,866
5 Sheets-Sheet 5
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April 6, 1937.
A. H. RADAscH ET A;
2,075,866
TREATMENT OF TAR
MTQRNE'Y
April-6, 1937.
A. H. RADAscH ET AL
2,075,866
TREATMENT oF TAR
Filed March 2l, 1934
'5 Sheets-Sheet 5
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Patented Apr. 6, 1937
2,075,866 i
UNITED STATES
PATENT oFFlcEA `
2,075,866
TREATMENT OF TAR
Arthur H. Radasch, Bloomfield, and Wilfred M.
Bywater, Weehawken, N. J., assignors to The
Barrett Company, New York, N. Y., a corpora
tion of New Jersey
Application March 21, 1934, Serial No. 716,698
In Canada July 15, 1933
24 Claims.
(Cl. 260--154)
This invention relates to an improved method
of treating liquid hydrocarbon material such as
coal tar to recover tar acids from it in the form
of carbolates. The tar or other material is heat
5 ed above its initial boiling point and flashed,
vapors are separated from the non-volatilized
tar-acid-containing residue and tar acids are
distilled from this residue and recovered as car
>bolate by extraction of the tar acids from the
l0 vapors.
By “tar acids” we mean the volatiliz
able constituents of tar which form salts with
strong alkalies, more particularly, rthe phenols,
such as phenol, cresols, and cresylic acids` of
commerce~ or their components.
This invention
l5 includes both the method and apparatus for car
rying it. out.
More particularly, the invention relates to a
process of ñashing tar or other hydrocarbon ma
terial in which part but not all of the tar acids
20 are vaporized by ñashing, tar acids are separat
ed from non-acid constituents in the vapor phase
by alkaline extraction of the flashed vapors, and
vapors remaining after the alkaline extraction
are then used in whole or in part in the inert gas
distillation of tar acids from the residueirom
tion of this invention, the tar is heated aboveY
its initial boiling point and then ilashed into a
vapor-separating chamber. The vapors of low
er boiling constituents, which are vaporized by
the self-contained heat of the tar at the tem- ß‘ä
perature of íiashing, are oollectediseparately froml
the undistilled residue. The hot residue is then
subjected to inert gas distillation ‘in which` tar
acids are volatilized from the residue.
The heat
for the distillation is preferably supplied by the '10
self-contained heat of the residue, although ad
ditional heat may be applied.
The inert gases used in this secondary distilla
tion comprise gases which are inert both to tar
acids and to caustic and which serve as a car- l5
rier for the tar-acid vapors.
“Gas” 4is used in
a broad sense to include fixed gases such as ni
trogen and condensable vapors such as steam and
oil vapors. The gas introduced into the still in
cludes vapors of neutral oils which repress or ‘20
minimize the vaporization of neutral oils of the
same boiling range from the tar in the still. To
the extent that the Vaporizationof neutral oils
is repressed, the secondary distillation is selec
tive, and tar acids are distilled from the residue P25
Without the distillation of the corresponding
the flashing operation.
The process of this invention thus includesl amount of neutral oils. The heat required for
two distilling steps, viz. a primary distillation, the distillation of the tar acids is thus less than
which is preferably carried out in a pipe-coil that required by the ordinary methods of dis
30 still by heating the tar above its initial boiling tillation in which neutral oils of the same boil- 30
ing range as the tar acids are necessarily vapor
point, ñashing it and separating the flashed va
ized in order to distill 01T the tar acids.
pors from the undistilled residue, and a second
An aklaline reagent is brought into contact
ary distillation in which tar acids are distilled
with the gases and vapors from the inert gas
from the residue resulting from the primary dis
35 tillation. Inert gases which preferably include distillation to extract tar-acid vapors and thus "3.5
vapors of non-acid or neutral oil constituents are separate them from the vapors of non-acid con
stituents. Tar acids are thus extracted in the
employed in the secondary distillation.
vapor phase and the carbolateV formed separates
The process of the present invention is appli
cable to the treatment of tars such as coke
40 oven tars, gas-retort tars, vertical-retort tars,
and low-temperature tars and other tar-acid and
neutral-oil-containing
hydrocarbon
materials
such as coal tar distillates or distillation residues.
It may be applied to the treatment of raw mois
45 ture-containing tar or stripped tar, etc., or to
the separate treatment of tar fractions such as
the heavy tar from the collector main of a coke
oven plant or the light tar or tarry oil from the
condensers of such a plant. It may be applied
to the treatment of mixtures containing coal tar,
etc. The invention will be described more par
ticularly as applied to the treatment of coke
oven tar.
55
In the primary distillation or flashing opera
from the vapors.
'I'he temperature and concentration of the -40
caustic employed for the vapor phase extraction
of the tar acids may be so regulated as-to effect
removal of the tar-acid vapors Without substan
tial condensation of neutral oils in the caustic
extractor as a separate oil layer; ordinarily, E 5
however, some neutral oil will dissolve in and
be removed with the carbolate. If the gases and
vapors resulting from the inert gas distillation
are cooled, oils will be condensed which may be 50
separately collected. If the gases and vapors `
from the still are cooled before they enter the
caustic extractor, tar-acid oils Will be condensed
from them. If they are cooled after tar-acid'
vapors have been separated in the caustic tower, y55 v
2
2,075,866
neutral oils or oils of low tar-acid content will
be obtained.
The vapors from the flashing operation may be
similarly treated wit-h an alkaline reagent for
5 the recovery as carbolate of the contained tar
acids. The vapors (chiefly of non-acid constit
uents) remaining after this extraction may ad
vantageously be employed as part of the inert
gases used in the distillation of the residue from
10 the iiashing operation.
If the vapors from the flashing operation leave
the vapor-separating chamber at a temperature
above 200° C. it may be advisable to cool them
to this temperature or below before bringing them
15 into contact with the caustic solution in order to
prevent the vaporization of too much water from
gases such as steam, nitrogen (preferably heat
ed) , etc., may be introduced either into the pri
mary or into the secondary distilling system i1’
desirable, to aid in the distillation.
Ordinarily the residue from the primary dis
tillation will be at a suñiciently high temperature
to permit the desired distillation of tar acids by
the gases in the secondary distillation without
further addition of heat; however, additional
heat may be supplied either to the residue or to 10
the gases, if necessary or desirable. According
to the preferred method of operation, all of the
heat required for the operation is supplied to the
tar in a tar heater before the tar is flashed. The
heater may be an ordinary direct-fired heater
or any other suitable type of heater may be em
ployed such as a heat interchanger in which
steam or hot oil, etc. is employed for heating the
stead of cooling the vapors before they enter_ tar. The waste flue gases from a coke-oven bat
20 the caustic tower, the concentration and temper
tery or gas-retort plant, etc. or from a tar still 20
ature of the caustic may be so regulated as to ef
may be used for the heating.
fect condensation of neutral` oils in the caustic
By regulating the temperature and rate of sup
the caustic and the production of a solution so
concentrated as to be diñ‘icult to handle. In
extractor simultaneously with the extraction of
the tar-acid vapors.
25 Both the caustic extractor employed for ex
tracting the gases and vapors from the secondary
distillation and the caustic extractor employed
for extracting the vapors from the flashing op
eration may be operated in a similar manner,
30 i. e. with or without simultaneous condensation
of neutral oils or each may be operated diiierent
ly. Furthermore, the caustic extractions can be
carried out either as batch operations or as con
tinuous operations with gradual additions of
35 fresh caustic and gradual withdrawal of carbolate
from the alkaline liquid; both extractions may
be operated alike in this respect or differently.
The two tar-acid extraction processes may be
carried on independently of each other, using
40 separate caustic feeds to each extractor and col
lecting separate carbolate fractions. As an al
ternative method, the same caustic may be em
ployed for extracting tar acids from the two gas
streams successively, feeding fresh caustic into
45 one extractor in excess and then employing the
unsaturated solution in the other extractor. As
a further alternative, the carbolate from both
extractions may run to a common receiver and
blend therein with the caustic used for the ex
50 traction. It is desirable to bring a large volume
of caustic into contact with the gases and thus
effect a relatively complete absorption of the tar
acids from the gases. This is conveniently done
by repeatedly recirculating a portion of the
55 caustic-carbolate mixture formed. If the same
caustic solution is used in both caustic extrac
tors, the evaporation of water from the solution
or condensation of vapors from the gases in one
of the caustic extractors may be offset by opposite
60 conditions in the other extractor.
Inert gases may be generated during the treat
ment of tar owing both to decomposition of the
tar and to the vaporization of moisture present
in the tar. By providing a vent for the excess
65 gases the apparatus of the inert-gas or secondary
distillation will be operated at constant, approxi
mately atmospheric pressure. This secondary
distillation is advantageously carried out at at
mospheric pressure, although pressures above or
70 below atmospheric pressure will be employed, if
desirable, by providing suitable valves and means
for removal of material. likewise, the ñashing
operation, although advantageously carried out
at atmospheric pressure may be operated at pres
75 sures higher or lower than atmospheric. Inert
ply of the gases, etc., the vaporization of the tar
acids from the residue from the flashing opera
tion may be carried to the point where the resi
due is practically completely stripped or nearly
stripped of tar acids, or to the point where chieiiy
the lower boiling acids, forA example, phenol and
cresols, are removed and recovered. A partial
removal of the more readily vaporizable tar acids
can be effected with the removal of but a small'
quantity of the higher boiling and more diffi
cultly removable acids. By controlling the flash
ing operation so that the greater portion of the
lower boiling tar acids are vaporized and then
selectively distilling the lower boiling tar acids
from the residue, a high percentage of the lower
boiling tar acids can be recovered as carbolate
relatively free from higher boiling acids.
According to a preferred method of carrying v 40
out the process, the inert gases employed in the
secondary distillation comprise at least a por
tion of the vapors remaining after the extraction
of the vapors produced during the primary dis
tillation. These extracted vapors may be blended
with extracted gases and vapors from the sec
ondary distillation and the mixture employed for
the secondary distillation. According to the pre
ferred method of operation, the inert gases em
ployed in the process are produced within the
process and the addition of steam or nitrogen or
other inert gases from some other source is un
necessary.
According to one preferred method of opera
tion, the extracted vapors from the flashing op
eration are all introduced into the still used for
the secondary distillation without the addition of
other inert gases. The gases and vapors result
ing from the secondary distillation after tar-acid
extraction are subjected to total condensation to
condense oils and the remaining non-condensable
gases are bled to the atmosphere or otherwise
treated. As an alternative method of operation,
part of the extracted vapors resulting from the
secondary distillation are blended With all or a
part of the extracted vapors flashed from the tar
and used in the inert gas distillation and the
balance of the _gases and vapors from the second
ary distillation are passed through a total con
denser and then vented to the atmosphere or
otherwise treated. Part or all of the extracted
vapors from the ñashing operation may be blend
ed with part or all of the gases from the second
ary distillation before these gases and vapors pass
through the caustic extractor, if desirable.
In 75
:accresce
<any caseythe extracted vapors ifrom thefiiash
.ing operationmay be subjected to'cooling to con
dense neutral oils before being .used inthe inert
gas distillation. The uncondensed vapors lmay >be
blended‘with the gases and vapors from the sec
ondarydistillation before or after vthe latter have
passed through the caustic extractor. lîf blended
with these gases and vapors before ,passing
'through- the caustic extractor; they maybe blend
10 ed before or after the gases from the secondary
distillation have been cooled to separate tar-acid
oils. If blended with these gases and vapors after
caustic extraction, they may be blended with
them either before or after regulated cooling to
15 condense part of the neutral-oil constituents.
Gases and vapors from either .distillation which
are'not further used in-the secondary distillation
.are vented to the atmosphere-.or otherwise dis
posed o-f. Thevented gases .are advantageously
20 cooled to recover their oil 4content before dis
charging the non-condensable gas to the atmos
.thettempexzatureliconnitions :and cedricentr-ationy of
„caustic,f;etc.rrmay be=- different. `Ingeneral, it-is
@advisable pto :recycle throughl each vcaustic ex
.tractor ¿a :.portion ofthe carbolate rformedin it
-and blend it withya vsmall amount of fresh' caus
tic inforder :thattherefwill-be a'large .surface of
liquid ».-exposed Ato `>ther-action of the vgases and
vapors. .For-»this purpose a portion cf thecaustic
from thecaust-io extractor 14 is withdrawnr through
the pipe Sandrecirculated by thepump l through
.the heat ir1terc'harrgcrr8.»and sprayed into the
.caustic-extractorthrough the sprays 9. -Fresh
is »admitted .preferably continuously,
« caustic
`through .thepipe t6. Similar >apparatus is pro
xvided -for recirculating carbolate `through the
caustic extractor 5. -Carbolate from the caustic
extractor’ 4 is drawn off into the receiver II and
phere.
Although the primary distillation of this in
vention is preferably a pipe coil distillation with
25 ñashing of the heated tar in a vapor-separating
chamber, other methods of distillation may be
employed that result in a continuous production
of vapors and preferably'a continuous'production
of residue also,falthough the withdrawal of-resi
30 due from the still may be intermittent.
The invention will be further described in con
nection with the accompanying drawings which
.from .the extractor »5 into the receiver I2. If
vfresh caustic is continuously added to the ex
ti‘actors the carbolate formed is preferably drawn ' 20
01T continuously; if the icausticis added Vbatch
wise, the carbolate 1 is .preferable ' removed vbatch
wlse.
The tar enters the system through the pipe I3.
.It isheated-in the tar heaterl and then flashed in
thevapor box 2. Steamand the vapors of lower
boiling constituents of the-tar pass. from the vapor
vbox through the line I5 into the caustic extractor
4. Here tar acids are-extracted with caustic or
other suitable alkaline reagent.
The resulting
`gasesincludevapors of neutraloils from which a
largegpart or all of the tar-acid vapors have been
show in a more or less diagrammatic manner removed; they pass through the line I6 into the
apparatus suitable for carrying out the process bottom of the still 3.
Hot residue from the vapor box passes through
of the invention but it-is intended and is to .be
the
line I'I into the-still 3 and is distributed by
understood that the vinvention .is not limited
the nozzles I8 over baliling means in the still.
thereto.
-Fig. l shows a pipe coil still connected with Gasesfroni thestill whichinclude tar-acid and
two caustic extractors and means for subjecting neutral oil vapors;- pass through the line I9 into
the residue from the vapor box of the still to the bottom of the caustic extractor 5. The gases 40
vwhich leave thecaustic extractor 5 include va
the inert gas distillation of this invention;
`Fig. 2 shows a modified arrangement of tar pors of neutral oils from which a large part or all
ofthe tar-acidvapors have been removed. They
acid extraction apparatus;
Fig. 3 is a modiiication of the apparatus shown pass through the main 20 into the bottom of the
secondary still 3. AGases .from the extractor l
45 in Fig. 1 equipped with means forvthe condensa
which include vapors of neutral oil flashed from
tion of separate neutral oil fractions;
Fig. 4 shows a pipe coil still as in Fig. 1 and two the tar in the primary distillation enter the still -3
.through the line I6. A blower 2| is provided to
caustic extractors but with a diiferentarrange
cause circulation of the gases and vapors through
ment of the pipe coil still and the still for treat
the cycle of the still .3 and the caustic extractor 5:
ing
the
residue;
and
50
,Instead of combining the steam and neutral
Fig. 5 shows a modiñcation in which acid oils
oil vapors fromthe flashing operation with the
are condensed.
In Fig. 1 an ordinarytar heater is shown at I. recycled gases ahead of the blower,> they may be
The vapor box 2 is of the type usually employed combined with the recycled gases after they have
in connection with a pipe coil still. The residue passed through the blower if desired.
55
In order~ to provide for the elimination from the
from the primary distillation is drawn off from
the vapor box 2 into the secondary still 3 where system of excess inert .gases which include steam
it is subjected to distillation by contact with an generated from water present in the tar, a portion
inert gas. Caustic extractors are shown at 4 and of the recirculated gases is vented through a
bleed provided at 22, and a condenser 23 is shown Gi)
5. Tar acids flashed from the tar inthe vapor
60
separating chamber? are extracted in the vapor for condensing neutral oils »and steam from the
phase in the caustic extractor 4, and tar acids gases bled vfrom the system. A decanter v2li is
distilled from the residue in the still l3 during the provided for collecting the condensate and sep
inert .gas distillation are extracted in the vapor arating the neutral oils from water. With the
bleed located as shown in the drawings, Vall of the
phase in extractor 5.
The caustic extractors may advantageously be gases from the caustic extractor 4 enter the still
towers packed with baiiling means, such as steel 3 and only a portion of the gases V`and vapors of
yneutral oils from the caustic extractor 5 pass
screening, over which trickles the caustic-car
bolate solution introduced through sprays at through the still. A portion of the gases and va
pors which leave the caustic extractor 5 are bled 70
the top.
70
Both extractors may be-operatedin the same from the -system and are not recycled through the
general manner, `although since >the gases and still 3. The residue from the secondarydistilla
vapors passing rthrough the caustic extractor 5 tion in the still 3 is drawn off through the line
usually contain ahigher percentage ofsteam> than -25 andcollected in the'receiver 26.
.those passing through the caustic extractor 4,
VThe heating of the tar in the tarfheater maybe
4
2,075,866
so regulated that the vapors which pass oiï from
the vapor box include vapors of tar acids of a
more or less deñnite boiling range so that the
carbolate collected in the receiver I| will include
the tar acids of this boiling range. Or the prí
mary distillation may be controlled so that the tar
acids in the residue from the flashing operation
include tar acids of a particular boiling range,
which is a higher boiling range than that of tar
10 acids that are ilashed in the vapor box. Or the
inert gas distillation in the still 3 may be so con
trolled, by regulating the rate at which the gases
‘ are circulated through the still 3, as to vaporize a
greater or less percentage of the higher boiling
15 tar acids from the residue in this still 3 together
with most of the lower boiling tar acids present
left in this residue after the iiashing operation.
In this manner, the composition of the carbolate
collected in the receiver I2 may to some extent
20 be controlled.
Coal tar varies not only in the percentage of its
tar-acid content but also in the nature of the tar
acids which it contains. With diiîerent tars dif
ferent temperature conditions should prevail in
25 order to produce particular results. However, in
general, if coke-oven tar is heated in a tar heater
sufficiently so that upon ilashing the resultant va-v
pors will be at a temperature of say 175° C. and
then flashed, the tar acids in the carbolate ob
30 tained in the receiver II may comprise a higher
percentage of phenol than the tar acids in the
carbolate in receiver I2. The temperature to
which the tar should be heated to obtain this
vapor temperature will be around 25° C. higher,
35 i. e. 200° C.
Fig. 2 shows an arrangement of apparatus es
pecially adapted for obtaining two fractions of
carbolate, one containing the major portion of
phenol and the other containing higher phenols.
The arrangement shown in this figure makes pos
sible an improved fractionation to obtain a phenol
fraction especially low in the higher phenols.
In this iigure the legend I0| designates a pipe
coil tar heater into which tar may be pumped at
Tar leaves the _heater I0| by means of a pipe
|03 and is passed into a vapor separating cham
ber |04.
The vapor separating chamber |04 is provided
with a reñux column |05 of any suitable type,
such as a balile tower, a packed tower, or a bell and
tray tower. The tower is provided with a liquid
inlet |06 for introducing reiiux liquid, and a liq
uid outlet I0'I having a valve |08 for the removal
of reñux residue from the base of the reñux co1
umn. At or near the top of the column is pro
vided a vapor conduit |09 for the passage of va
pors from the reñux column to a caustic extractoror phenol absorber | I0.
The phenol absorber I I 0 may be of any suitable
type, such as described in connection with Fig. 1,
for example a packed tower. It is adapted for
the passage of vapor up therethrough in counter
current to and in intimate contact with a stream
of sodium hydroxide solution. The tower I|0
r has a caustic inlet III at or near the top thereof
and an outlet |I2 for conducting carbolate to a
suitable receiver II3.
The Withdrawal of car
bolate through conduit ||2 may be controlled by
a valve I I4. It is is desired to recirculate caustic
which has been used for extraction, it may be
withdrawn through recirculating line II5 by
means of pump ||6 and reintroduced into the
caustic inlet |||.
The phenol absorber I I0 has a vapor outlet I i1
75 for the removal of extracted neutral oil vapors
and for their passage to vapor line I|8 to be here
inafter described. A suitable bleeder I|9 and
condenser |20 may be provided for condensing a
portion of the oil vapors drawn oiî through out
let line II'I. Oils thus condensed may be col
lected in a receiver I2| and employed as reflux
liquid in the tower |05. A return pipe line |22
and pump |23 are shown for this purpose.
The vapor separating chamber or flash box
|04 is provided with a liquid draw-off |24 for
removing residue from the iirst step of the dis
tillation. This draw-off is connected to a spray
head |25 at the top of a tower |26 which may be
of the packed type or other contact type of tower
adapted for the passage of a liquid and gas in
countercurrent relation therethrough.
The tower |26 has a draw-oir |21 for remov
ing liquid residue and has at the end adjacent
the liquid inlet a conduit |28 for the removal of
gases and vapors and for conducting them to a "20
second phenol absorber |29 of type similar to
or diiîerent from phenol absorber |I0. This
absorber is provided with a caustic inlet |30 and
a draw-off I3l’ for carbolate for conducting it
to a receiver |32. Recirculating line |33 and
pump |34 are provided for the recirculation of
caustic and carbolate where desired. At or near
the top of the tower there is provided a vapor
outlet conduit IIS for conducting vapors and
gases from the caustic tower back to the extract
ing tower |26, thus providing a closed circuit be
tween the Vapor extraction tower |26 and the
phenol absorption tower |29. A blower |35 may
be provided for impelling the gases and vapors
through this circuit.
-
This apparatus is capable of varied operation.
However, the following description is given as
illustrative of the methods which may be em
ployed for obtaining a plurality of phenolate or
carbolate fractions from tar~acid-containing tar' 40
by means of this process.
Crude coke oven tar containing for example
around 3% of tar acids is introduced at |02 into
the tar heater IBI and is heated to a temperature
of around 275° C.
45
At this temperature the tar leaves the heater
and enters the vapor separating chamber or flash
box |04 where a portion of the volatile constitu
ents are vaporized and pass up through the reilux
column |05. Residue is withdrawn through 50
draw-oil |24. A suitable quantity of reñux liquid is introduced at |06 so that the vapors in passing
up through the tower are gradually cooled to a
temperature of around 175° C. Because of the
presence of lower boiling oils as well as steam
from the Water content of ordinary tar this tem
perature is high enough to maintain phenol,
which has a boiling point of l82-183° C., in vapor
form. The residue from the reñuxing may be
withdrawn at |01 at a temperature around 235°
C. for example.
Oil bled from the line I|'| may be employed as
this reñux liquid. When such a liquid is em
ployed, it also undergoes a rectiñcation in its pas
sage down through the tower. Reiiux residue
may be withdrawn from the rectifying column
|05 by means of outlet |01 and collected as a
separate tar-acid-containing oil, or by closing
valve |08 this residue may be permitted to over
flow into the vapor separating chamber |04 and 70
may then he collected together with the residue
from the tar distillation and may be withdrawn
together therewith to the tower |26 for the re
moval of contained higher boiling tar acids.
Alternatively reflux may be supplied by use of
5
2,075,866
a cooling coil in the upper 'part of the column
Fig. 3 is a inodiñcation of the apparatus shown
|05; a cooling medium is circulated in this coil
to elîect partial condensation of vapors in the
tower, the condensate flowing downward counter
current to the ascending vapors.
for removal of neutral oil from the vapors flashed
from the vapor box after the extraction of tar
By the above rectification higher boiling
phenols are fractionally removed from the gas
stream, the gases and vapors entering the tower
||0 are composed primarily of low boiling oils',
and the phenols contained are low boiling
phenols, for instance the oil (which is here in
vapor form) may have a boiling range of ‘115°
to 200° C. and may also contain some water.
With the vapors entering the phenol absorber
| l0 at a temperature around 175° C. such vapors
will constitute around 2 to 6% of the total> tar
and may contain on the average from 15-35% of
tar acids based on the oil. Eflicient extraction
of these tar acids from the vapors may be ob
tained in the tower I I0 and these tar acids, about
in Fig. 1 and includes separate condensing means »
acids and the removal of neutral oil from the ’
vapors from the secondary still 3a after the ex
traction of tar acids. VThe tar is heated in the
tar heater Ia and flashed in the vapor box _2a.
rlî‘he residue from the flashing operation flows
cil to the still 3a by gravity. The vapors from
the vapor box pass first through the'caustic
tower 4a and then through the condenser 30
where they are partially cooled and a portion
of the neutral oil is condensed. The cooling in`
the condenser 33 may be regulated to condense
any desired fraction of! the neutral“ oil vapors,
but in no case are the vapors cooled below the
dewpoint of the gases for steam.
The tar acid extraction in the caustic extractor
4a is preferably so regulated that there is sub 20
50% of which, for example, may be phenol, may
stantially no condensation of neutral oils. ' `A
be withdrawn and collected in receiver ||3.
The dephenolized or extracted vapors are then
withdrawn at ||1 and passed to the secondary
distillation tower |26. Prior to their introduc
tion into this tower they may be partly cooled
to condense a portion of the oils therefrom, if
desired, but preferably they are maintained at
portion of the carbolate formed in the extractor
substantially the temperature they left the phenol
absorber, around M55-175° C., and the bleeder
|50 and condenser |20 are provided for removing
a portion of the oils as condensate and prevent
ing building up of pressure in the system. A por
tion of this oil condensate may then be returned
Cl to the reilux column |05 to serve as reflux liquid.
Residue from vapor separating chamber |04
passes without substantial loss of temperature
into the tower |26 where it is brought into inti
mate contact with the gases and vapors passing
40 up through the tower. This results in the re
moval from the tar residue of a substantial pro
portion of the remaining volatile tar-acid con
stituents.
Where, under the conditions of operation de
45 scribed, reflux liquid is separately withdrawn
from tower |05, the residue entering the tower
|26 will be a pitch or partly distilled tar amount
ing to around 85% of the total tar distilled. In
this tower |20, for example, about 1% or more
50 of the original tar may be removed as tar acids
from the pitch residue by the circulation of the
vapors through the tower.
The gases containing these tar-acid vapors,
principally tar acids of higher molecular weight
55 than phenol, pass through phenol absorption
tower §29 where tar acids are removed and col
lected as phenolates in receiver |32. The gases
and vapors substantially denuded of their tar
acid content in tower |29 are reintroduced to
60 tower |23 after passing through the line ||8 to
the blower |35. By this method of recircula
tion the removal of neutral oils from the residue
introduced into tower |26` is inhibited because of
the fact that the vapors brought into contact
65 therewith comprise substantial amounts of va
pors of neutral oils. The heat of the residue it
self serves to supply the requisite heat of vapori
zation to the tar acids and thus promotes the
separation. Since the gases and vapors enter
ing the extractor tower |26 are substantially free
from or low’in tar acids, there is substantially no
or at most a relatively low partial pressure of
tar acids to inhibit their vaporization and they
are thus rapidly vaporized and carried off in the`
75 gas stream.
is recirculated through the heat interchanger
8a and sprayed into the gases and vapors in the
caustic extractor through the sprays 9a. Ex
cess carbolate is drawn ofi into the storage tank
lla.. Fresh caustic is added at any suitable
point in the cycle as through the pipe |0a.
The gases and vapors which pass off from the
condenserr 30 contain steam and neutral oils of
low boiling range. They pass through the pipe
|6a into the still 3a.
The‘ gases and vapors from the still 3a pass
ñrst through the caustic extractor 5a and then
through the condenser 3|. In the condenser 3|
the cooling of the gases is regulated to condense
neutral oils of any desired boiling range. The
extraction of tar acids from the gases and vaporsy
in the caustic extractor is preferably so regulated
that there is no condensation of neutral oils.
Caustic is recirculated as described in connection
with the caustic extractor 4a of Fig. 3 and excess
carbolate is drawn off into the storage tank |2a.
The gases and vapors from the condenser 3| ‘
are preferably blended with the gases and vapors L15
from the condenser 30 before reentering the still
3a. Means may be provided for separately in-ï
troducing the two gas streams into the still3a, if
desirable.
"
Neutral oils are drawn oi’r‘ from the condenser 50
30 into the oil storage tank 32 and neutral oils
from the condenser 3| are drawn oft into theV
storage tank 33. The condensers 30 and-3| may
be of any desirable type.
'I‘hey may be heat in
terchangers in which tar or water is used as the ,
cooling medium. The tar may be preheated by
heat interchange with the hot gases and vapors
before entering the tar heater |a. Direct con
tact condensers may be employed in which' case
water may be used as the cooling medium _or oil 60
which has been condensed from the gases may be
cooled and sprayed into the gases and vapors to '
effect further condensation of oil. Rectiñers may
be used where desirable. Fractional condensing
means may be employed to collect two or more 65
cuts.
Fig. 3 shows condensers for removing neutral
oils from both gas streams. If desirable, onlyV
one condenser may be employed for removing -
neutral oil from one of the gas streams, i.- e.
either from the gases and vapors from the flash
ing operation or from the inert gas distillation
and the other gas stream will then pass'dire'ctly
from the caustic extractor to the still 3a.
6
agresseL
The apparatus of Fig. 4 shows means for blend
ing gases resulting from the vapor phase extrac
tion of tar acids from the, vapors from the flash
ing operation with the gases and vapors from
5 the inert gas distillation before they are ex
tracted.
The vapors which separate from the residue in
the vapor box 2c pass over through the main |5c
into the extractor 4c where they are brought into
10 direct and intimate contact with an alkaline re
agent capable of extracting the tar acids.
'I’he neutral-oil vapors remaining after the
caustic extraction escape from the extractor 4c
through the line |6c. They are eventually, at
l5 least in part, used in the inert gas distillation of
the residue from the ilashing operation in the
secondary still 3c, but according to the specific
example shown in Fig. 4 they are first blended
with the gases and vapors coming from this still
20 and'again scrubbed with caustic in the extractor
5c before entering the still.
The residue from the vapor box 2c is sub
jected to further distillation in the still 3c in an
atmosphere of inert gases which includes vapors
25 of neutral oils some of which are vaporized from
theV tar in the vapor box 2c and some of which
are vaporized in the still 3c and recirculated
through the caustic tower 5c. The gases and
vapors from this secondary distillation leave the
30 still 3c through the main |9c and are combined
with vapors from the caustic extractor 4c and
the combined gases pass by the main 40 into the
caustic extractor 5c. Carbolate formed is drawn
off into the storage tank I2C. Tar acids com
35 bine with the caustic in the extractor and the
remaining gases which include vapors of neutral
oils which escape from the caustic extractor are
recycled through the still 3c by means of the
blower 2|c and the mains 20c and 4|.
4U The blower for circulating the gases and vapors
lated cooling the vaporspass through the caustic
extractor ddfwhere tar acids are extracted in the
vapor phase.. A carbolate formed is collected in
the tank Ild. The remaining gases and vapors
pass through the main |6d into the secondary
still 3d in which the residue from the vapor box
2d is subjected to inert gas distillation.
The gases and vapors from the inert gas dis
tillation in the still 3d pass through the main |911
to the condenser 52 in which tar-acid oils are 10
condensed. These tar-acid oilsk are drawn oiî
into the storage tank 53. The resulting gases and
vapors which still contain vapors or tar'acids are
then passed through the caustic extractorV 5d
where tar acids are extracted in the> vapor phase
and recovered as carbolate in the tank | 2d. The
remaining gases and vapors pass through the
main 20d and a portion of .them is combined with
vapors from the ilashing operationfand the com
bined gases are-circulated throughthe secondary
still 3d. A bleed condenser 23d is provided for
recovering oil from the remainder of the gases
and vapors as previously described.
Of the tar acids contained in the vapors en
tering the condensers, the higher boiling acids
are condensed in the acid oils and the lower boil
ing tar acids are subsequently recovered as carbo
late in the extractors. Fig. 5 shows a condenser
preceding each of the caustic extractors. Either
of these condensers may be omitted. The vapors
from the flashing operation may pass through a
condenser and caustic extractor and the inert
gases from the secondary still may be subjected
to extraction without condensation, or the vapors
from the secondary still may be subjected to con
densation and then extraction while the yvapors
from the flashing operation are subjected only
to vapor phase extraction without condensation.
Fig. 5 is a somewhat similar to Fig. 1 in that
the vapors from both caustic extractors are com
through the dephenolizer and caustic extractor is
advantageously located in the‘line 20c by which
bined and introduced into the secondary still.
Modifications of the apparatus shown in Fig. 4.
the gases and vapors are returned to the still 3c.
may include condensers before one or both of the
The blower may, however, be located in the main
caustic extractors as inFig. 5. By including a
condenser between the vapor box 2c and the
caustic extractor 4c of Fig. 4, an oil fraction containing the higher boiling tar acids may be col-lected from the gases before they enter the caustic
45 40 or elsewhere, as desired.
Neutral oils may be condensed from the system
where and as desired, for example in either or
both caustic extractors or in coolers provided for
this purpose. The recycled inert gases and _neu
50 tral oil vapors may be reheated as desired before
extractor 4c.
With a condenser in the line |90 to
cool the gases from the secondary still before they
they reenterv the dephenolizer. Modifications of
are combined with the gases in the main |60, a
theprocess, such as these, may be made without
going beyond the scope of this invention, al
though the preferred method of operating ap
55 paratus such as that shown in Fig. 4 comprises
supplying the entire heat for both the primary
and secondary distillations to the tar in the tar
tar-acid'oil may be condensed from these gases
and vapors before they> are subjected to caustic
extraction in the extractor 5c.
Various modiñcations are possible in which the
tar or other hydrocarbon material is flashed in
heater lc and a minimum amount of neutral
oils is recovered as such. The residue from the
60 secondary distillation then contains more neutral
oils than the residue from an ordinary distilla
tion in which the vaporization of neutral oils is
not selectively repressed. The carbolate will ordi
narily dissolve some neutral oil, and some neutral
65 oil will be obtained from the vent condenser 23o.
In Fig. 5 provision is made for obtaining tar
acid oils by cooling vapors from the flashing op
eration or gases andvapors from the secondary
distillation before extraction with caustic or other
70 alkaline reagent. The tar is heated in the heater
|11` and flashed in the vapor box 2d. Vapors pass
through the main |5d to the condenser 5U where
they are subjected to regulated cooling and a
tar-acid oil, produced by condensation, is drawn
75 off' into the storage tank 5|. `After this regu
the vapor box and the vapors and residue are
separated and the residue is treated for its tar
acid content.
The rate at which gases are circulated through
the residue from the first distillation in the inert
gas distilling operation will'vary depending upon
the temperature ci. the residue treated and the
amount of tar acids, etc., recovered. For ex
ample, if ordinary coke-oven tar containing three
percent of low boiling tar acids is treated and the
tar is heated to 175° C. in the tarv heater and then
flashed in the vapor box so that the vapors pass
off through the main l5 at about 150° C. and the
residueis drawn off into the secondary still3 at
about 150° C., about 65 percent. of the tar acids
can be recovered as carbolate in the receivers ||
and I2 without any substantial amount of neu
tral oils by circulating the gases through >the sec
ondary still at a rate of about 300 cubicfeet per
2,075,866
4. The method of Atreating `tar-acid- and neu
gallon of hot tar to be treated. If the gases are
to be cooled for the separate recovery of neutral
tral-oil-containing hydrocarbon material, which
oil or acid oil and all of the heat for the inert gas
comprises distilling the material at a tempera
distillation is to be supplied by the hot residue,
ture at Which a mixture of vapors of tar acids
and neutral oils is evolved therefrom and a hot
Ui the gases Will be circulated at a greater rate or
the tar should be heated to a higher temperature
and the gases circulated at the same rate if the
same recovery of tar acids is desired. When tar~
Yacid oils are condensed, part of the acids are re
covered in those oils and part in the form of car
tar-acid-containing residue remains, separately
extracting tar acids from the vapors from this
distillation by contact with an alkaline reagent,
separately collecting the hot tar-acid-containing
residue and bringing at least- a portion of the 10
bolate. If gases from the ñashing operation are v vapors from which tar acids have been eX
blended with the extracted gases resulting from tracted by the aforesaid Contact with alkaline
the inert distillation, then the .temperature and reagent into direct contact with the residue. to
amount of the blended gases must be taken into aid inthe distillation of tar acids therefrom.~
5. The method of treating tar, which com~ 15
ï consideration in calculating the rate at which
the gases are recirculated. If additional hot prises heating coal tar above its initial boiling
gases are added, such as additional steam, etc., point and ñashing the heated Atar thereby sep
the temperature and amount of these added gases arating vapors of lower boiling. tar acid and
>must also be given consideration. By cooling the neutral oil constituents of the tar from the
gases and vapors from the inert gas distillation to
residue, removing the residue from'the Zone of 20
separately recover one or more neutral-oil or
separation, extracting tar acids from the vapors
fromthe fiashing operation by contact with an
alkaline reagent While leaving neutral oils in
acid-oil fractions, a pitch residue of higher or
lower melting point may be produced as desired.
By cooling the vapors from the ñrst distillation
before introducing them into the secondary still
one or more neutral-oil or acid-oil fractions of
lower boiling range may be separately recovered.
r"his application is a continuation in part of our
SO
copending application, Serial No. 546,448, filed
June 24, 1931.
We claim:
1. ‘The method of treating tar-acid- and neu
tral-oil-containing liquid hydrocarbon material
which comprises heating the hydrocarbon mate
C1: ivi rial above its initial boiling point and flashing the
heated material toV vaporize tar acids therefrom,
separately collecting the vapors and heated resi
due, passing vapo-rs thus collected in contact with
an alkaline reagent to absorb the tar acid vapors,
40 vaporizing tar acids from the residue in a current
of inert gases and bringing the gases containing
tar acid vapors- from said residue into contact
With an alakaline reagent separate from the
aforesaid alkaline reagent whereby tar acid va
pors are extracted.
-
'
2. The method of treating hydrocarbon mate
rial, which comprises heating tar-acid- and neu
tral-oil-containing liquid hydrocarbon material
above its initial boiling point and flashing the
heated material to vaporize tar acids therefrom,
separately collecting the vapors and heated resi
due, passing vapors thus collected in contact with
an alkaline reagent to absorb the tar acid vapors,
vaporizing tar acids from the residue in a current
of inert gases by the heat of the residue and then
f.
Ui
extracting tar acids from the resulting gases and
vapors by an alkaline reagent separate from the
aforesaid alkaline reagent.
3. The method of treating hydrocarbon mate
rial which comprises heating tar-acid- and neu
tral-oil-containing hydrocarbon material above
its initial boiling point and flashing the heated
material to vaporize tar acids therefrom, sepa
rately collecting the vapors and heated residue,
passing vapors thus collected in contact with an
alkaline reagent to absorb the tar acid vapors,
then vaporizing tar acids from the heated residue
in a current of inert gases by the self-contained
heat of the residue, extracting tar acids from the
to vaporize tar acids from the residue.
6. The method o-f treating tar, which corn
prises heating coal tar above its initial boiling
point, flashing the heated tar thereby Vaporiz
ing neutral oils and a portion of the tar acids 30
and producing a hot tar-acid-containing resi
due, separating the vapors from the residue, re
moving the residue from the zone of separa~
tion, extracting tar acids from the vapors by di
rect contact With an alkaline reagent, passing 35
at least a portion of the .vapors of neutral oils
in admixture With inert gases through the hot
residue thereby distilling tar acids from the res
idue, extracting tar’ acids from the resulting
gases and vapors and recycling through the hot
residue a portion of the resulting neutral oil
vapors together with vapors of neutral oils from
the flashing operation.
'7. The method of treating tar, which com
prises heating coal tar above its initial boiling 45
point, ñashing the heated tar thereby Vaporiz
ing neutral oils and a portion of the tar acids
and producing a hot tar-acid-containing resi
due, separately collecting the residue and the
vapors, passing through the residue a mixture 50'
of inert gases 'including 'neutral oil vapors,
blending with the resulting gases and vapors,
vapors of neutral oils ñashed from the tar in 'the
flashing operation, extracting tar acids from the
blended vapors by contact with an alkaline re- í
agent and recycling through the hot residue
from the ñashing operation at least a portion of Y
the remaining inert gases and vapors of neutral
oils to effect the selectivevaporization of tar
acids
therefrom.
.
Y
8. The method of treating tar, which com
(i 0
prises heating coal tar above its initial boiling
point, flashing the heated tar thereby Vaporiz
ing neutral oils and a portion of the tar acids
and producing a hot tar-acid-containing resi
due, separately collecting theresidue from the
through the heated residue in admixture with in-.
vapors, selectively vaporizing tar acids from the
hot residue by passing therethrough a mixture
of inert gases including neutral oil vapors, eX
tracting tar acids vaporized from said residue by
contacting the tar acid vapors with an alkaline
reagent, blending at least a portion of theremain
ing neutral oil vapors With vapors of neutral oil
flashed from the tar in the flashing y0in-eration
ert gases.
and recycling the blended gases through 'the hot 75
resulting gases and vapors by contact with an
alkaline reagent separate from the aforesaid al
kaline reagent and recycling at least a portion of
theìremaining vapors of non-acidrconstitutents
75
vapor form and using at least a portion of these
neutral oil vapors in admixture With inert gases 25
~
~
8
2,075,866
residue from the ñashing operation to effect the
selective vaporization of tar acids therefrom.
9. The method of treating tar, which com
prises heating coal tar above its initial boiling
5 point, flashing the heated tar thereby vaporiz
ing neutral oils and a portion of the tar acids
and producing a hot tar-acid-containing resi
due, separately collecting the residue from the
vapors, selectively vaporizing tar acids from the
10 hot residue by passing therethrough a mixture
of inert gases including neutral oil vapors, ex
tracting tar acids from the resulting gases and
vapors by contact with an alkaline reagent, ex
tracting tar acids from the vapors flashed from
15 the heated tar by contact with an alkaline re
agent, and passing vapors of neutral oils result
ing from both extractions through the heated
residue from the flashing operation in eifecting
the distillation of tar acids therefrom.
20
10. The method of treating Wet tar, which
comprises heating it to a sufficient temperature
to flash off substantially its entire water con
tent, thereby separating steam and vapors of
lower boiling constituents of the tar from the
25 non-volatilized residue, separating the vapors
from the hot residue, removing the hot residue
from the zone of separation and then passing
this steam together with vapors of neutral oils
through the residue While still hot to distill tar
30 acids therefrom.
11. The method of treating wet coal tar, which
comprises heating it in a continuous still to a
temperature sufficient to distill olif substantially
its entire water content, continuously separating
35 vapors thus produced from the resulting residue,
continuously removing residue from the zone of
separation, continuously passing at least a portion
of the steam thus produced in admixture with
neutral oil vapors through the hot residue to dis
till tar acids therefrom and extracting tar acids
from the resulting gases and vapors by contact
with an alkaline reagent.
12. The method of treating wet coal tar, which
comprises distilling off steam and lower boiling
constituents and separating them from the re
sulting hot residue, removing hot residue from
the zone of separation, distilling tar acids from
the hot residue in a current oi' this steam mixed
with neutral oil vapors, extracting tar acids from
50 the resulting vapors by contact with an alkaline
reagent and blending at least a portion of the
resulting neutral oil vapors with the steam for
the distillation of tar acids from the residue.
13. The method of treating tar, which com
55 prises heating coal tar above its initial boiling
point and flashing the heated tar thereby vapor
izing vapors of lower boiling tar acid and neutral
oil constituents, separating the vapors from the
resulting non-volatilized residue, removing resi
due from the zone of separation, extracting tar
acids from these vapors by contact With an alka
line reagent and employing all of the remaining
gases resulting from the flashing in the vapori
zation of tar acids from the residue.
(55
14. The method of treating tar, which com
prises heating coal tar above its initial boiling
point and flashing the heated tar thereby vapor
izing vapors of lower boiling tar acid and neutral
oil constituents, separating the vapors from the
7() resulting hot residue, removing residue from the
Zone of separation, extracting tar acids from the
vapors by contact with an alkaline reagent and
introducing inert gases and neutral oil vapors
remaining after this tar-acid extraction directly
into intimate contact with the hot residue from
the ñashing' operation together with other inert
gases and vapors of neutral oils to vaporize tar
acids bythe self-contained heat of the residue
therefrom.
15. The method of treating tar, which com
prises heating coal tar above its initial boiling
point, flashing the heated tar thereby vaporizing
neutral oils and a part of the tar acids, leaving
a tar-acid-containing residue, separating the va
pors from the residue, removing residue from the 10
zone of separation, extracting tar acids from the
vapors by contact With an alkaline reagent and
then cooling them to separate neutral oil there
from and using at least a portion of the remaining
neutral-oil vapors in the distillation of tar acids
from the hot residue.
16. The method of treating tar, which com
prises heating coal tar above its initial boiling
point, flashing the heated tar thereby vaporizing
neutral oils and a part of the tar acids as vapors 20
leaving a tar-acid-containing residue, separating
the vapors from the hot residue, removing residue
from the zone of separation, extracting tar acids
from the vapors by contact with an alkaline re
agent, using at least a portion of the resulting 25
vapors of neutral oils in admixture with inert
gases to effect the distillation of tar acids from
the hot residue, extracting tar acids from the gases
and vapors from this inert gas distillation by con
tact with an alkaline reagent and cooling them to
condense a portion of the resulting neutral oils
vapors and blending at least a portion of the re
sulting neutral oil vapors with neutral oil vapors
from the flashing operation, and using them in the
distillation of tar- acids from the hot residue.
35
17. The method of treating tar, which com
prises heating it above its initial boiling point,
flashing the tar, separating vapors from the re
sulting hot residue, removing the residue from
the zone o1” separation, distilling tar acids from 40
the residue in a current of inert gases including
neutral-oil vapors, extracting tar acids from the
resulting gases and vapors by Contact with an al
kaline reagent and subjecting them to regulated
cooling to separate part but not all of the neutral 45
oil therefrom and recycling at least a portion of
the resulting neutral oil vapors through the hot
residue, in admixture with inert gases and neu
tral-oil vapors from the flashing operation.
18. The method of >treating tar, which comprises
heating it above its initial boiling point to a tem
perature of about 200° C. or higher, ñashing the
thus heated tar to vaporize tar acids therefrom,
separating vapors from the resulting hot residue,
removing residue from the zone of separation,
subjecting the separated vapors to a rectification
treatment to condense vapors of tar acids while
leaving uncondensed vapors of lower boiling tar
acids and neutral oils, extracting tar acids from
said uncondensed vapors by Contact with an al
kaline reagent, distilling tar acids from the afore
said residue in a current of inert gases, extract
ing tar acids from the resulting gases and vapors
by an alkaline reagent and using remaining gases
and vapors in the inert gas distillation of the res
idue.
65
19. The method of treating tar to distill it
and obtain an acid oil and a carbolate contain
ing tar acids recovered from the tar, which com
prises heating it above its initial boiling point 70
and flashing the heated tar to vaporize a por
tion of the lower boiling tar acids therefrom,
separating vapors from the resulting hot residue,
removing residue from the zone of separation,
distilling tar acids from the residue in a current
9
2,075,866
òf inert gases, cooling the resulting gases and
vapors to condense part but not all of the oil
vapors and to form an acid oil condensate con
taining a selective fraction of the higher boiling
tar acids in said tar, extracting tar acids from
the resulting gases and vapors by an alkaline
reagent to obtain a carbolate containing a sec
ond selective fraction of the higher boiling tar
acids in said tar and using remaining gases and
vapors in the inert gas distillation of the residue.
20. The method of treating tar to distill it
and obtain an acid oil and a carbolate contain
ing tar acids recovered from the tar, which com
prises heating it above its initial boiling point
15 and flashing the heated tar to vaporize a por
tion of the lower boiling tar acids therefrom,
separating vapors from the resulting hot residue,
removing residue from the zone of separation,
cooling the vapors to condense part but not all
of the oil vapors contained therein and to form
an acid oil condensate containing a selective
fraction of the lower boiling tar acids in said tar,
extracting tar acids from the resulting vapors by
contactl with an alkaline reagent to obtain a car
bolate containing a second selective fraction of
the lower boiling tar acids in said tar and using
at least a part of the remaining vapors in inert
gas distillation of the residue.
21. The method of treating tar containing
30 phenols which comprises heating the tar to a
temperature sumcient to distill oif a portion of
the neutral oils and phenols, separating the va
pors from the residue and bringing them into
intimate contact with an alkaline reagent, there
DD Cl by extracting phenols from the vapors so as to
form a phenolic extract, passing said residue
While still at a high temperature into direct con
tact with an inert vapor stream whereby addi
tional phenols are evaporated from the residue,
40 bringing the resultant vapor stream containing
phenols into intimate contact with an alkaline
reagent so as to extract phenols therefrom, and
rectified vapors into intimate contact with an
alkaline reagent so as to remove phenols from
the vapors and produce substantially phenol-free
vapors, passing the residue from said flashing
while yet at a high temperature into direct con
tact with vapors comprising at least a portion
of said phenol-free vapors so as to evaporate
phenols from said residue and produce a vapor
mixture containing phenols, passing said mixture
into intimate contact with an alkaline reagent 10
thereby removing phenols from the vapor and
producing a second substantially phenol-free va
por and bringing at least a portion of said sec
ond substantially phenol-free vapor into contact
with said residue toI evaporate phenols from the 15
residue and collecting the phenol product from
said second-mentioned phenol removal step
apart from the phenol product from said ñrst
mentioned phenol removal step.
`
23. The method of treating hydrocarbon ma
20
terial, which comprises (1) heating tar-acid
and neutral-oil-containing liquid hydrocarbon
material to vaporize a portion thereoi", (2) sep
arately collecting the vapors and unvaporized
residue, (3) vaporizing tar acids from the residue 25
and separately bringing the vapors from (1) and
(3) aforesaid into contact with alkaline reagent
to extract tar acid vapors and form carbolates.
24. The method of treating tar which com
prises heating it above its initial boiling point 30
to a temperature of about 200° C. or higher,
flashing the thus heated tar to vaporize tar acids
therefrom, separating vapors from the resulting
hot residue, removing residue from the zone of
separation, subjecting the separated vapors to' 35
a rectification treatment by direct contact with
a neutral oil condensate to condense vapors of
tar acids while leaving uncondensed vapors of
lower boiling tar acids and neutral oils, extract
ing tar acids from said uncondensed vapors by 40
an alkaline reagent, cooling at least a portion of
the extracted vapors to condense neutral oils
collecting the resultant phenolic extract apart therefrom, employing the neutral oil condensate
from that obtained in the first mentioned phenol thus obtained for the aforesaid rectification of 45
' vapors from the flashing of heated tar, distilling
extraction step.
22. The method of treating tar containing tar acids from the aforesaid residue in a current
phenols which comprises heating the tar to a of inert gases containing neutral oil vapors, ex
temperature sufficient so that upon subsequent tracting tar acids from the resulting gases and
flashing a pitch residue and a vapor distillate
50 at a temperature substantially above 175° C. are
obtained, subjecting the resultant vapors to rec
tiiication whereby they are partly cooled to a
temperature not below about 17 5° C., passing the
vapors by an alkaline reagent and using re
maining gases and vapors in the inert gas dis
tillation of said residue.
ARTHUR H. RADASCH.
WILFRED M. BYWATER.
50
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