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Патент USA US2106234

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Y Jan. 25, 1938.
Filed Feb. 19, 1954
¿Zinc B_Br'ay
Patented Jan. 25,` i938
Prem# ortica
' @its
' 2,166,234
_ Unic' n. Bray, rains verses Estates, Calif., as
slgnor to Union Oil Company of California,
Los Angeles, Calif., a corporation of California
Application February 19, 1934, semi No. 111,963 "
5 Claims.
(Cl. 196-13)
This invention relates to the extraction of oils
nary decantation means. The rañinate phase isv
usually found to contain a small‘quantity of the
plicable tothe treatment of other oils, it refers - selective solvent and the extract phase ordinarily
contains a relatively large quantity of the sol
more particularly to the production of lubricat
These fractions may be puriñed by distil- 5A
ing oil by a selective solvent extraction process.
lation whereby the solvent is distilled away from
It has been found that desirable parafllnic hy
by employing a selective solvent. Although ap
drocarbons can be' separated from the undesirable ' the hydrocarbon oils.
In the usual solvent extraction of mineral oil
oleñnic, naphthenic and/or aromatic compounds .
' -by the use of solvents which selectively dissolve with the above mentioned selective solvents, the
10 the undesirable hydrocarbons but which exhibit separation is not- complete. Particularly, »all .of 10
the parañinic hydrocarbons, i. e. the more valu
only a very limited solvent power _upon the desir
able paraflinic hydrocarbons.
When I use the term “paramnic hydrocarbons”
I mean those highly saturated compounds which
15 are present in petroleum and are characterized
bya low temperature viscosity susceptibility, i. e.,
they exhibit a minimum 'change in viscosity for
a. given change in temperature. They also are
characterized by relative stability to air and sun
20 light, exhibiting little tendency toward discolora
tion or sludge formation. This deñ‘nition is not
meant to include those compounds which are
usually‘solid or semi-solid at ordinary tempera
tures and which are known as "wax” or “pe
trolatum”; but, of course, it is obvious that my
invention is meant to also include the selective
extraction of waxy oils. As a matter of conven
ience hereafter, I will refer to the undesirable
components, such as oleiinic, naphthenic and/or
30 aromatic hydrocarbons, as the “non-parafñnic”
components of petroleum. These fractions are
able lubricants, are not obtained inthe raflinate
phase but instead,„some of the high grade paraf
flnic oil fractions are found in the extract phase.
Also, the extract phase may contain kcertain frac 15
tions of oil characterized by properties interme
ldiate low and high grade. lThese fractions arel
not desired in the ñnal rafllnate but are valuable
as second grade oils- when separated from. the
fractions of low quality.
-It has been -known in the solvent extraction art
kthat after _making a primary separation‘of rafli- _'
'nate- fromjextract, additional fractions can be
made to separate from the extract phase by one
or more'reductions of temperature which corre
spondingly reduce the solubility of these oils of
relatively high parañinicity in the extract phase.
These oils `then form intermediate -ra‘ñinates .
which can be separately recovered by decanta
tion from the remaining extract phase. The 30
solubility of oils of relatively high parañlniclty in
characterized by a relatively high temperature ’ '~ the extract phase can also be reduced by the ad
viscosity susceptibility and are relatively un-l dition of an anti-solvent thereto, the presence of
which causes a phase-separation between anin- »
vstable to air and sunlight,` exhibiting discolora
termediate raiiin'ate and remaining extract phase. 35
35 tion and sludge formation`
'A number of selective solvents for extraction This> intermediate rañinate 'comprises second
‘have been found; for example, it has been shown grade oil of quality'superior -to the oil remaining
dissolved in the extract phase.- V '
that such materials as aniline, chloraniline, nitro
benzene, dichlorethyl ether, phenol, chloro
An anti-solvent maybe Ydefined/.as a"`ñiate'rlal
phenol, cresol and cresol with a small proportion` which tends to prevent the solution of a hydro- 40
of water, for instance 4%, are highly selective carbon fraction which, except for the presence of _ ,
as solvents for the non-paraiiinic hydrocarbons. the anti-solvent, would be dissolved in the extract
phase upon extraction of the oilwith a selective
When these solvents are commingled with pe
troleum or petroleum fractions under the proper solvent. A number vof substances are suitable
for use as an anti-solvent; for instance liquid
45 conditions of temperature, the-undesirable non
parañinic hydrocarbons passinto solution to a > normally gaseous hydrocarbons such- as liquid
_ greater or less extent but a substantial propor'- ~ ethane, propane or butane, or- methyl, ethyl or
isopropyl -alco ols, methyl cellosolve (mono
tion of the desirable parañinic hydrocarbons re
mains undissolved.4 The solution of' undesirable. ‘ methyl- ether o! ethylene glycol) and other oxy
50 hydrocarbons and solvent settles to the bottom ` genated compounds such as acetone or methyl 50
of the container and forms an extract phase when ' acetate.
relatively heavy"solvents are employed._ The`
relatively light paraiiinic hydrocarbons rise to
. the top of the vessel and form a ramnate phase.
These phases are then readily separable by ordi
Evenrwater Vmay-be used as an anti
solvent .when the -ïselective solvent with which it
is employed vis at least partly soluble therein. A„One
vor more of these anti-solvents may be employed.
vÉlu Some cases, the addition of an
` 2,106,284
to the extract phase renders temperature reduc
tion unnecessary to separate relatively high
quality oil fractions therefrom. In other cases,
Jection of intermediate raiiinate can also be
omitted or reduced in degree’by removing a con
siderable portion of the selective solvent from the
refrigeration of the extract phase will be neces
extract phase before treating the extract phase
sary but will be less than when no anti-solvent is . with a`n anti-solvent at the temperature appro
present. In a solvent extraction process of this priate for separation of the relatively paraflinic
character, the expense of refrigeration is la sub
fractions. In addition to the effect of the anti
solvent, the solubility of the relatively valuable
stantial item in the cost of operation. ~ My proc
ess lowers this cost.
‘ parañinic fractions in the extract is reduced by
Under _certain conditions, the anti-solvent
which may be' employed may be a substance
which is a selective solvent when employed alone.
For instance, there may be mixed with the ex
tract phase to function as an anti-solvent a; selec
18 tive solvent having less solvent power for the
the lpresence of a lower proportion of selective 10
solvent. In some cases; unless the proportion of
solvent in the extract phase is reduced, excessive
ly large amounts of anti-solvent must be added
to cause phase separation of the extract phase
`and rejection vof an intermediate rafllnate.
Therefore, it is another object of my invention
higher grade mat‘erial present therein than the
solvent power of the'selective solvent originally ' to separate an oil by means of a. selective solvent
used to produce the extract. As an example, oil into a raffinate and an extract, remove a portion
may be treated with chloraniline or a mixture of of the selective solvent from the extract phase
20 liquid sulphur dioxideand benzene to obtain an and then intermix said extract with an anti-sol 20
¢extract phase. These solvents are characterized vent to separate an intermediate raftlnatefrom
by high solvent power for higher grade’ material.
To the extract phase thus produced there may
be added liquid sulphur dioxide or other solvent
25 having relatively less solvent power for the higher
grade material. For this reason and under these
conditons, certain selective solvents >may be
employed as anti-solvents and by their presence
in the extract phase the higher grade fractions
therein are rejected to form an intermediate
I have found that when the anti-solvent em
ployed is a liquid, normally gaseous substance
such as liquid propane, butane, sulphur dioxide
the extract phase.
The ñgure is a schematic arrangement of -one
form of apparatus‘which may be employed to
carry out my process.
Referring to the figure, oil enters the system via
line I0 controlled by valve II by action of pump
I2 and passes into primary extractor I3, wherein
it is countercurrently extracted with selective
solvent introduced through line I4 controlled by 30
valve I5 by action of pump I6. Raflinate phase
from extractor I3 is removed via line I 1 and valve
I8 and passes through coil 2,0 in heater 2l prior
to entrance into secondary extractor 23 via line `
35 or the like, the rejection of desirable oils from - 23. Countercurrent extraction isagain accom- '
plished in 23 by selective solvent introduced
the extract phase by the presence 'of said anti
solvent is aidedewhen the pressure is sutliciently through line 25 controlled by valve 26 by action
of pump 2l. Rafiinate phase issues from` ex-Í
reduced in the rejection stage to cause evapora
tion of a portion. of the anti-solvent,_ thereby
40 reducing the temperature of the mixture of the
extract phase and anti-solvent remaining liquid.
In this case the liquid, normally gaseous mate
rial, for instance ethane, propane, butane or sim
ilar substances, not'only functions as an anti
45 solvent to remove the relatively high grade frac
these vapors are removed through line 36 con
tions from the extract phase but also operates
as an internal refrigerant. After evaporation for
internal refrigeration, sufficient amounts of said
liquid, normally gaseous material should remain
50 associated in the liquid phase with the extract to
function as'an anti-solvent.
It is an object of my invention to separate an
oil by means of a selective solvent into a raflinate
tractor23 through 30 controlled by valve 3| and.
passes through coil 32 in heater 33 and line 34 40
connected with vapor separator 35. Its tempera
ture is raised suñiciently in 32 to vaporize in 35
the selective solvent associated therewith and
trolled by valve 31. High grade rañinate -exits
via line 38 and valve 39. Intermediate extract
phase is removed from secondary extractor 23
through line 40 controlled by valve 4I by action
of pump 42.
When the same solvent or a different solvent 50
of substantially the same or lower solvent power
is employed in both extractors I3 and 23, the
raflinate from the primary extractor is preferably
phase and an extract'phase and to intermix saicl ' heated before extraction in the secondary extrac
extract phase with an anti-solvent to separate tor in order- to increase the amount of interme
an intermediate raffinate from said extract.
diate extract produced yin the secondary extractor.
It is a further object of my invention to sep
When the solvent employed in 23 has greater. sol
arate an oil into a more paraflinic rañinate phase vent power than the solvent used in I3, heater
and a; less parafflnic extract phase by means of V2i may be omitted in some cases.
a selective solvent having relatively high solvent
Extract phase from primary extractor I3 passes
power for high grade material present in the through line 45 controlled by valve 46. When oil and to intermix said extract> phase with a it is desired to lower the proportion of selective
selective solvent characterized by a lower solvent solvent in theextract phase prior to the addition
`powerfor the high grade material whereby the of the anti-solvent thereto, valve 41 inline 45
latter functions as an anti-solvent andan' in
may be entirely closed in order to by-pass the 65
termediate raiiinate is rejected from said extract. stream of extract phase via line 48 and valve 49.
It is another object of my invention to recover‘ In this event, the extract phase. flows through _‘
an intermediate rafiinate from said extract by coil 50, disposed in heatexchange relationship
mixing the extract phase with a liquid, normally with the material flowing through coil 63, thence
gaseous anti-solvent and employing said anti
passes via line 5I through coil 52 situated in heat
solvent as an internal refrigerant to aid in re
er 53, after which it travels through line 54 into
ducing the temperature of the extract phase to vaporizer 55. Sufficient heat is imparted to the
prcêmote the separation of the intermediate rafli extract phase to cause vaporization of the desired
na e.
>amount of selective solvent therefrom in 55.
The refrigeration of the extract phase for rc
These vapors pass from the system via line 56,
controlled by valve 51. The extract phase con
taining the desired proportion of selective sol-.
vent passes from vaporizer 55 through line 60
controlled by valve 6| by action of pump 62. It
Cl then passes through coil 63 in heat exchange re
lationship with coil 50.
The material then iiows
through line 64 and valve 65. The temperature
0f the extract phase may be further lowered by v
other cooling if desired before introduction of
the anti-solvent. Line 64 connects with line 45.
In'order to avoid heating the total amount of ex
tract phase produced in extractor I3, valves 41
and 49 may be controlled so that only a portion
of the extract passing through line 45 is by-passed
through line 48 and the heating system. Suf
ñcient solvent is then removed in 55 so that when
the streams of extract flowing through lines 64
and 45 are reunited, the mixture will comprise
Vapors exit from fractionating tower |06 via line
|09 controlled by valve ||0. vResidual-oil passes
from the tower through line ||| controlled by
valve ||2. Intermediate side cut distillates can
be taken from tower |06 by lines ||3 and |_|4
controlled by valves ||5 and ||6 respectively.
Fractionation in -|06 may be accomplished under
vacuum and/or with steam injection as desired.
As an example of the operation of the appara
tus disclosed in the ñgure, a dewaxed Santa Fe 10
Springs lubricating distillate characterized by'
A. P. I. gravity at 60° F. of 19.8°, carbon residue
of 0.24%, acid number of'0.16 and viscosity grav
ity constant. of 0.874 was extracted in extractor
|3 with 175 volume percent. Ichloraniline at n45°
F. The raffinate thus produced was heated in.
coil 20 to 80° F. at which temperature extraction
in 23 with 120 volume percent. chloraniline was
conducted. The high grade rafñnate passing from
_ the desired proportion of solvent. In some cases
it may not be necessary to lower theiproportion - the system via line 38 was characterized by a 20
of solvent to oil in the extract phase passing from gravity of 29.9° A. P.v I., carbon residue of 0.01%,
extractor I3 via line 45 before the addition of , _acid number of 0.04 and viscosity gravity constant _
the anti-solvena In that event valves 49 and of 0.804. .
Suñìcient extract phase passing from extractor
65 are closed and valve 41 remains open.
I3 Wasbypassed via line 48 through heater 52
Anti-solvent is introduced into the stream 0f
and vapor separator 55'so that upon re-uniting
extract ñowing through line 45 by line 10 con.
trolled by valve 1| by action of pump 12. The" with the stream passing through valve 41 the
combined vstream passes into oriiìce mixer 13` _ combined stream comprised 70 volume percent.
Where thorough agitation occurs, after which it chloraniline based on the original charge of oil.
passesinto cooler 15 via line_14. Cooling may To this stream was added 105 volume percent. i" '
be accomplished by any desired means such as liquid propane as an anti-solvent. Sufñcient pro
pane was vaporized in cooler 15 to reduce the
by external refrigeration but when liquid, ‘nor
mally gaseous anti-solvent is employed I prefer temperature of the mixture to 40° F. at which
to employ internal refrigeration. That is, the phase separation occurred. Extract removed via
pressure is suiìciently reduced in cooler 15 to line 9| had an A. P. I. gravity >at 60° F. ofv'1.3. fili4
Rejected intermediate rañìnate _freed of propane
vaporize a portion oi the anti-solvent with con
and chloraniline passing through line |00 had an
sequent cooling of the remaining liquid. The va
A. P. I. gravity at 60° F. of 21.9 carbon residue of
- porized portion of the -anti-solventexits from
cooler 15 through line> 16 controlled by valve 11. 0.16%, acid number of 0.04_and viscosity gravity
constant of 0.857;- In one modified operation, .. '
40 The extract phase and anti-solvent are sufñcient
ly cooled ’in 15 to cause phase separation in sep- . only the propane was vaporized from the inter
‘ arator 80 to which the chilled mixture passes by mediate rejected rañinate in 91 and the unvaf
action of pump 8| through line 82 controlled by porized residue in line |00 was combinedwith the
valve 83. Extract phase from. 80 passes through intermediate extract passing through line 90.
The mixture was4 distilled under vacuum into sep
45 line-84 controlled by valve 85, through heater 86
and line 81 into vapor separator 88. _The stream arate cuts of desired boiling point range in heater
|05 and fractionating tower |06.
is suñiciently heated in 86 to vaporize theanti
As a further modification of my process, ex-_
-solvent and the selective solvent. These va
pors pass through exit line 89 controlled by valve tractor 23 may be omitted in some cases, all ofthe
90. 'I‘he low grade extract oil is removed through extraction` taking place in I3. . _In -this event,
heater 2| is employed to distill the selective sol
line 9| controlled by valve 92.
Rafûnate phase rejected in separatorv 80 passes vent from 'the raflinate passing through line- |1.
It will be understood that the foregoing is mere
through line 93controlled by valve 94 through
heater 95 and line 96 into vapor separator 91. lyillustrative of certain embodiments of my in
vention and that many modifications may be.
55 Suiñcient heat is imparted in 95 to vaporize the
made therein without
' anti-solvent and any selective solvent associated
of my invention.
with the intermediate grade rañinate. _ These va
pors are removed through line 98 controlled by , 1 I claim: ‘
valve 99. In some cases it is desired to heat suf
00 iiciently to remove only the anti-solvent from the
oil and solvent in vapor separator 91. Th'e inter
mediate grade raiiinate exits from 91 through
line _|00 controlled by valve |0| by action of pump
` "~'~\»
'Although theintermediate grade raffinate iìow->
ing through line V|00 and the intermediate grade
~ extract produced in secondary extractor 23_ may
be separately recovered and separately distilled
to obtain ñnal products within the desired boiling
point range, I prefer to intermix these streams
flowing through lines |00 and 40.
This com
bined stream .is heated' in_-heater |05 prior to
passage into fractionating tower |06 via line |01.
Fractionating tower |06 may be provided with the
usual traysI |08 and other usual appurtenances.
departing from the spirit
1. A process for the separation of parafiìnic'
and non-parañlnic fractions from mineral oil con 60'
taining- thesame which'comprises extracting said
oil with a selective solvent, separating the extract _ _ I `
phase soluble in said solvent from the rañinate
phase insoluble therein, reducing the selective sol
vent'content of said extract phase, then commin 65
gling said extract phase with an anti-solvent and
separating from said extract phase an interme
diate raiiinate` rendered insoluble ‘in said extract
phase by said anti-solvent said intermediate raf
finate containing the bulk of _said anti-solvent.
2. A process for the separation'of paraiïinic
and non-paraffinic' fractions >from mineral oil
containing the- same which comprises extracting
said oil with a selective solvent, Aseparating vthe
extract phase soluble in said solvent from the
2, 106, 234
raiiinate phase insoluble therein, reducing the tract phase soluble in saidisolvent from the raf
selective solvent content of said extract phase,then
nnate phase insoluble therein, commingling said
commingling said extract phase with an anti-sol- » extract phase with a liquid, normally gaseous
vent, cooling said extract phase, and separating
anti-solvent, vaporizing a portion of said anti
from said extract phase an intermediate raffinate ' solvent, cooling said extract phase by internal re
rendered insoluble in said extract phase by said frigeration and l separating from said extract
anti-solvent said intermediate raillnate contain
ing the bulk of said anti-solvent.
3. A process for the separation oi.' paraiiinic
and non-paraiiinic fractions from mineral oil
containing the same which comprises extracting
said oil with a selective solvent, separating the
extract phase soluble in said solvent from the
ramnate phase insoluble therein, reducing4 the
15 selective solvent content of said extract phase,
then commingling said extract phase with a liq
uid, normally gaseous anti-solvent, vaporizing a
phase an intermediate raiilnate Vrendered insol
uble in sai'd extract phase by said anti-solvent
said intermediate raiilnate containing the bulk of
said anti-solvent.
5. A process for the separation of parafilnic
and vnon-paraiiinic fractions from mineral oil
containing the same which comprises extracting
said oil with a selective solvent, separating the
extract phase soluble in said solvent from the 15
raillnate phase insoluble therein, heating a por
tion of said extract phase to 4vaporize solvent, re
n portion of said anti-solvent, cooling said extract moving said vapors frcm said heated portion, in
.phase by internal refrigeration and separating- termixing the unheated portion of said extract
from said extract phase an intermediate raiiinate phase with the heated- portion, commingling said 20
rendered insoluble in said extractphase by said` extract phase with an anti-solvent and separat
anti-solvent said intermediate raflinate contain
ing from said extract phase an intermediate raf
ing the bulk of said anti-solvent.
finate rendered insoluble in said extract phase by
, 4. A process for the separation of paraiilnic and
said anti-solvent said intermediate ramnate con
non-paraiiinic fractions from mineral oil con
taining the bulk of said anti-solvent. »
taining the same which comprises extracting said`
oil with a selective solvent,v separating the ex
marc B'. BRAY‘
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