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Патент USA US2119759

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«Tune 7, 1938»
.
K. |_. WALLIN
» 2,119,159
SEPARATION oF wAx
Filed oct. 29, 1955
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SUZYQZZÍM
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IN VEN TOR.
Kenne-fh L. Wal/fn
ATTORNEY. `
_2,119,75el
Patented June 7, 1938
, UNITED STATES> PATENT oFFlcE
SEPARATION ' 0F WAXV >
Kenneth L. Wallin, san Pedro, Calif., assigner
to Union Oil Company of California, Los
- Angeles, Calif., a corporation of California
Application October 29, 1935, -Serial No. 47,276
7 Claims.
This invention relates to a process for separa
tion of Wax from a mixture thereof With asphal
tic and resinous materials. More. specifically, it
relates to a process for separating a mixture of
Wax and asphaltic and/or resinous'materials from
an oil containing same, and then separating and
resolving the thus obtained mixture into sepa
rate fractions' of Wax and of asphaltic and/or
resinous materials.
Asphalt may be separated from oil either by
distillation or solvent extraction. By the ordi
nary distillation methods, the oil, being more
volatile than the asphalt, is Vaporized, and may
then be condensed and recovered as a distillate,
while the asphalt, which is substantially non
volatile at the temperatures required to vaporize
(Cl. 19d-20) ,
Wax and asphalt containing oil with asolventA at
such a temperature that only the oil is dissolved
therein, the mixture of Wax and asphalt> being
recovered as the undissolved precipitate. The
further separation of the thus obtained mixture 5 y'
into the wax and asphalt components involves
diiñculties.
Thus, an ordinary asphalt-Wax mix
ture obtained as a precipitate from >a solvent ex
traction of an oil containing Wax and asphaltic
materials may be heatedk to a temperature' above
the .melting point of Wax without any separation
of an asphaltic phase.
One of the' known methods of resolving ’asphalt
Wax mixtures consists in commingling the as
phalt-wax mixture atl atmospheric orV elevated
10,;
temperatures with a light hydrocarbon solvent,
the oil, remains in the still and is recovered as a such as liquefied propane. The solvent dissolves
residue. If wax is present in the oil being de ~ the Wax from the asphalt, the Wax- being Vthen
asphaltized, the Wax is partially distilled over
recovered from the'hydrocarbon solvent solution
head in the medium and> heavy overhead dis
tillate fractions. A complete separation of the
remaining Wax from the asphaltic residue cannot
be obtained by any ordinary distillation means
owing to the high boiling point of certain of the
parai’ñn or Wax members p-resent.
If a further
separation of the Wax from the overhead dis
tillate is-desired, this must be accomplished by
processes such as cold settling, cold pressing or
centrifuging Which are Well known to those
skilled in the art.
v
by distillation ofthe solvent >or by refrigeration
of the solution to precipitate the Wax. However,
in the operation of this process, vsome of the as
phalt still remains dissolved in the solventsolu
tion along with the wax, and'comesI out together
with the Wax upon distillation or refrigeration.
It is, therefore, an object of the present inven
tion to provide a method which would obviate the
above diñ‘lculties and Which would lresolve such
asphalt-Wax mixtures more easily and economi
30
It has now been discovered that the relatively
ration of oil and asphaltic materials, itis possi
small amounts of oil still remaining in an as'
ble to use solvents in Which the oil is relatively phalt-Wax mixture obtained from a solvent eX
soluble but in Which the asphaltic materials are traction of an oil containing said substances, pre
E relatively insoluble. Thus, when naphtha, gaso
vent an easy resolution of the mixture into its 35
line or even the lighter hydrocarbons, such as constituent fractions. It was further discovered
liquid ethane, propane or butane, are employed ' that these relatively small amounts of oil act as a
as selective solvents to separate the asphaltic mutual solvent for both the Wax and *the as
cally.
'
'
‘
In employing solvent extraction for the sepa
materials from the oil, the former being substan
phaltic materials, >thus maintainingthem -in the
5 tially insoluble in the foregoing solvents, are left '
form ofv a homogeneous mixture above the melt
as a residue While the oil is separated from this ing point of the Wax.v It was still further dis
insoluble residue as a solution of oil in the sol
covered that the miscibility of the Wax and ofthe
vent. The term “solvent extraction”,.as used , asphaltv materials decrease With- a decrease in the
hereinbelow, is intended to include the above amount of oil remaining in such, `asphalt-Wax
5 type of asphalt precipitating solvents.
mixture. Thus, an asphalt-Wax mixturey as re 45,
Where Wax is present in the oil containing as
moved irom a solvent Yextraction. of an oil con
phaltic materials, the Wax may be separated taining same may be heated above the melting
along with the solvent and oil by maintaining the point of the Wax Without any phase separation,
solvent at a temperature at Which the Wax is
While the same mixture, after a substantial de
j dissolved in the solvent Vtogether >with the oil. oiling Will deposit the asphaltic substances as a
The wax may then be removed from the asphalt
bottom layer when the mixture is heated to or
free solution by chilling the solution and then somewhat above the melting point of the wax.
separating the precipitated wax by settling, filter
The -term “asphalt-Wax mixture”, as' used in
ing or centrifuging.
f
f
.
'
'
Another method consists in commingling the
the present specification and claims, includes
mixtures of these substances as obtained from
ne
2
2,119,759
solvent extraction of an oil by filtration, cen
trifuging or ordinary precipitation.
These mix
tures may be in a liquid, semi-solid or solid state.
Therefore, broadly stated, the invention re
sides in a method for resolving an asphalt-wax
mixture, as obtained from a solvent~ extraction
of an oil containing same, or from any other
similar source or operation, which comprises sub
stantially de-oiling said mixture and subsequent
ly raising the temperature of the thus de-oiled
mixture to the melting point of the wax.
The invention further resides in a method for
resolving an asphalt-wax mixture, as obtained
:from a solvent extraction or dewaxing of an oil
containing same, which comprises commingling
the asphalt-Wax mixture with new quantities of
a solvent under such condition that substantially
all of the oil still remaining in said mixture isdissolved in said solvent, removing the oil-solvent
20 mixture from the asphalt-wax mixture, and sub
sequently raising the temperature of the thus
substantially de-oiled asphalt-wax mixture to or
above the melting point of the wax, thus causing
the asphalt to precipitate from the liqueñed wax.
The above de-oiling step may be carried out by
cold leaching of the asphalt-wax mixture or by
dissolving the wax in a solvent followed by a
recrystallization by refrigeration.
As an example of the realization of the process
3.0. constituting the object of the present invention, a
mixture of oil, asphalt and wax, having a gravity
of 28.7° A. P. I. at 60° F. and a melting point of
115° F. was leachedv twice in propane at- _40° F.,
the ratio of propane to mixture being each time
3 to 1. After filtration and the depropanizing of
both the filtrate and the residual mixture, the
filtrate, which constituted 40% of the original
mixture treated, had a 21.0° A. P. I. gravity and
a. 0f’ F. pour point. The residual mass consisting
of wax, asphalt and some oil still dissolved there
in had al gravity of 34.3° A. P. I. at 60° F. and a
melting point of 125° F.
It is obvious that there is an optimum tempera
ture for the separation of asphalt from the de
oiled wax, this optimum temperature depending
on the character, viscosity, solvent power, etc.
of the wax. This temperature, however, must be
sufticient to reduce the viscosity of the wax to a
point at which the asphalt may readily settle out.
On the other hand it must be maintained suf
fìciently low to avoid dissolving of the more
soluble portions ofthe asphalt in the thus lique 10
fied wax.
The separation of the asphalt from the deoiled
wax-asphalt mixture may be carried out by a
simple sedimentation and decantation operation.
However, filtration may be resorted to for the 15
purpose of removing the asphalt from the melt
-ed wax. Obviously, the combination of the two
methods is also applicable.
For a better understanding of the present
invention reference is made to the accompanying 20
drawing which discloses one form of a flow dia
gram which may be employed for the realization
of the present invention. Referring to the draw
ing the oil containing wax and asphalt, is con
veyed through line II) into the iirst leaching tower
II wherein it is leached, as for example, at a
temperature of -40° F. with a lcooled solvent
such as propane introduced through line I2. The
oil-solvent mixture is removed from said leaching
tower through line I3 while the wax-asphalt 3,0
mixture still containing oil is conveyed through
line I5 to the second leaching tower I'I.
Here again, this wax-asphalt mixture contain
ing oil is leached with further quantities of cooled
solvent being introduced into said tower I1
through line I8. The solvent with the oil dis
solved therein is removed from said tower through
line I9. The residual mass, consisting of wax
asphalt and some oil still dissolved therein is
then removed from tower I'I through line 2|
wherein it is comrningled with optimum quanti
Although containing
ties of a solvent such as propane introduced
both asphalt and wax, it was impossible to sepa
rate them from each other, presumably due to the
through line 22. The mixture is then heated at
relatively high content of oil still present therein.
23 to a temperature at which the wax and asphalt
become dissolved in the solvent, so that the mass
The wax-asphalt mixture, leached as described
above, was. then recrystallized from propane and
ñltered at 0° F. This. operation was carried out
three timesV at the end of which the washedY wax
conveyed then through line 25 into the crystal
lizer 26 is homogeneous. This crystallizer is
cooled- as by means of a cooler 2l, the temperature
being such as to cause recrystallization of the
asphalt mixture constituted 48.6% by Weight of
wax-asphalt mixture. The solvent and oil are re
the original substance treated, had a gravity of
39.0° A. P. I. at 60° F. and a melting point of
133° F. 'I'his wax-asphalt mixture had only 3.4%
of oil still remaining therein as shown by an
acetone-benzene method of testing. On heat
ing the thus deoiled Wax-asphalt mixture to a
temperature at or above the melting point of the
wax, substantially all of the asphalt in the mix
ture settled out of the molten wax, and it was
found that the asphalt remained insoluble even
when the temperature'Was-raised up to 300° F.
It is to be noted that the wax-asphalt mixture,
moved from the crystallizer 26 through line 28 while
prior to. the iinal deoiling by recrystallization
from propane, still contained about 12% by
65 Weight of oil- Although applicant does not con
sider himself to be limited by any theory of the
case, it is his opinion that the presence of this
oilv in the asphalt-wax mixture prevents the
separation of the mixture into its component
parts, and that the removal of the larger propor
tion of the oil still remaining in the leached wax
permits the precipitation of the asphalt when the
temperature of the iinal mixture is raised sub
stantially to or above the melting point of the`
wax.
,
.i
the‘lwax-asphaltmixtureiswithdrawnthroughline
29. The wax-asphalt mixture thus removed from
the crystallizer 26 is then conveyed to a heater 30
in which the deoiled mixture is heated to a tem 55
perature at or above point of the wax, but below
the melting point of the asphalt. This heated
mixture is then conveyed through line 32
into separator 33 from >which the molten wax is
removed through line 34, while the solid asphalt
particles'precipitating to the bottom of sepa
rator 33 are Withdrawn through line 35.
‘ Although the invention has been described in
connection with the separation into its constituent
parts of an asphalt-Wax mixture obtained from a
solvent extractionl ordewaxing of an oil contain
ing these constituents, it is also possible to employ`
thesame method to separate the asphalt or simi
lar substances which have been added to an oil
containing only Wax. Thus, it is well known that 'Il
asphaltic materials are used as dewaxing aids in
the treatment’of waxy oils with solvents. In such
casesA the asphalticY substances help to coagulate
the particles of wax precipitated outV of solution,
thus aiding in the subsequent separation of the
2,119,759
Wax by any of the Well-known processes. Ob
viously, the resultant precipitate, when removed
from the filtrate, contains both the wax and the
thus added asphaltic materials. This mixture can
also be separated into its component parts by the
above method of de-oiling and subsequent lique
faction of the wax.
The above disclosure particularly referred to
the separation of wax from mixtures thereof with
10 asphaltic substances, It is to be understood, how
ever, that it is equally applicable to the removal
of wax from- mixtures containing resinous substances or resinous and asphaltic substances.
The present invention is not limited by any
15 theory of operation, nor any details which have
been given merely for purpose of illustration, but
is limited only and by the following claims which
cover the novelties inherent in the invention.
I claim:
l. In a process for resolving an asphalt-Wax
mixture obtained from an oil containing same
and still containing residual oil dissolved in said
mixture, the steps of removing substantially all
of the residual oil from said asphalt-wax mix
ture, and raising the temperature of the thus
de-oiled mixture to liquefy the wax th’êreby per
mitting the asphalt to precipitate therefrom.
2. In a process according to claim i, wherein
the de-oiled asphalt-wax mixture is heated to- a
temperature above the melting point of the wax
but below the melting point of the asphalt, Where
by the solid asphalt may precipitate from the
thus liqueñed wax.
3. A process for resolving an asphalt-wax mix
ture obtained from an oil containing same, said
mixture still containing residual oil dissolved
therein, which comprises treating said oil-con
taining asphalt-wax mixture with a solvent hav
ing preferential solubility for oil under conditions
whereby substantially all of said residual oil is re
moved from said asphalt-Wax mixture, separating
the thus de-oiled asphalt-Wax mixture from the
solvent and the thus removed residual oil, heat
ing the thus de-oiled asphalt-Wax mixture to a
3
temperature at which the wax is liquefied, but
the asphalt remains in a solid state, and remov- '
ing the solid asphalt from the thus liqueñed wax.
4. A process for resolving an asphalt-wax mix
ture obtained from an oil containing same, said 5
mixture still containing residual oil dissolved
therein, which comprises treating said oil-con
taining asphalt-wax mixture with propane under
conditions whereby substantially all of saidre
sidual oil is removed from said asphalt-wax mix
10
ture, separating the thus de-oiled asphalt-Wax
mixture from the propane and the thus removed
residual oil, heating the thus de-oiled asphalt
Wax mixture to a temperature at which- the Wax
is liquefied, but the asphalt remains in a solid 15
state, and removing the solid asphalt from the
thus liquefied Wax.
5. A process for resolving an asphalt, wax andv
oil mixture in which the oil content is approx
imately equal to the combined asphalt and Wax 20
content which comprises the steps of ñrst remov
ing substantially all of the oil contained in said
mixture and subsequently raising the tempera
ture of the thus de-oiled mixture to cause the
asphalt to precipitate therefrom and separating 26'
the precipitated asphalt from the Wax.
6. A process for resolving an asphalt, wax and
oil mixture in which the oil content is approx
imately equal to the combined asphalt and Wax
content which comprises the Steps of first re 30
moving oil from. said mixture to produce an as
phalt-wax mixture containing approximately
3.4% by Weight of soil and subsequently raising
the temperature of the thus de-oiled mixture’to
cause the asphalt to precipitate therefrom and 35
removing the precipitated asphalt from the Wax.
'7. A process as in claim 5 in which the asphalt,
wax and oil mixture is de-oiled by means of a
solvent employed under conditions whereby sub
stantially all of the oil contained in said mixture
is dissolved in the solventV and the oil-solvent
solution is removed from the asphalt-Wax mix
ture.
KENNETH L. WALLIN.
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