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Патент USA US2133240

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Oct. 11, 1938.
2,133,240
H. v. A'rwr-:LL
TREATMENT OF' HYDROCARBON OILS
Filedpec. 31, 1957
WN
INVENTOR
H4/?0¿D K 4TH/[LL
Ik
BY
H' S
ATTO RNEY
Patented oct. 11, 193s
2,133,249î
UNITED STATES; PATENT OFFICE ¿
2,133,240
TREATMENT 0F HYDROCARBON GILS
Harold V. Atwell, White Plains, N. Y., assigner
to Process Management Company, Inc., New
York, N. Y., a corporation of Delaware
Application December 31, 1937„ Serial No. 182,678
` 4 Claims.
This invention relates to the cracking of
hydrocarbon oils for the production of lower
boiiing products such as gasoline.
In accordance with the invention, hydrocarbon
which it is desired to subject to cracking, is
treated with a solvent capable of removing as
phaltic materials that may be contained in the
oil, the oil from which the asphaltic material
is removed is subjected to a cracking operation
10' and the asphaltic material is injected into` the
oil undergoing cracking so as to thus subject
the asphaltic material to cracking for conver
sion into lower boiling products.
The invention is especially directed to the
15 processing of stocks containing residual con
stituents of crude petroleum, such as topped and
reduced crudes. Such stocks contain greater or
less proportions ci asphaltic constituents whichy
are very readily converted into coke when the
cil is subjected to cracking. By removing these
potential coke-forming constituents from the
¥
oil, the oil is made susceptible to cracking under
much more drastic conditions, characterized withv
greatly increased rates of cracking perv pass with
eut coking diiiiculties. In accordance with the
invention these asphaltic materials which have
been removed from the char-ging stock are in
jected into the stream of oil undergoing cracking
so as to thus advantageously accomplish. the
30 cracking of the asphaltic materials and effect
conversion into additional gasoline. constituents.
In practicing the invention the charging stock
is treated with a liquefied normally gaseous hy
drocarbon, such as ethane, ethylene, propane,
propylene, butane, butylene, or mixtures thereof.,`
under conditions in which such hydrocarbon acts
as an anti-solvent of the asphaltic constituents
which are precipitated from the oil.
The oil
thus freed of the asphaltic, coke-forming con
40 stituents, may be subjected to cracking at a high
rate of cracking per pass adapted to sustain a
conversion into high anti-knock constituents
and the precipitated asphaltic material is intro
duced into the cracked products so that the
= asphaltic material is raised to a cracking tem
perature and subjected to conversion. In this
way the de-asphalted stock may be subjected to
temperatures and longer times of re
action than are applied to the precipitated rma
terial which may be introduced into the crack
zone at the latter portion thereof so that
the precipitated material may thus be subjected
to cracking for a’shorter time than the de
asphalted oil.
Although various solvents, or anti-solventsl of
(Cl‘. 1796-50)
asphaltic material, may be employed in the
practice of the invention, the hydrocarbons men
tioned are well adapted for the purpose of the
invention because of their excellent anti-solvent
properties, at temperatures close to normal tem
peratures, with respect to asphaltic constituents
contained »Y in
petroleum
oils.
Propane or va
hydrocarbon gas consisting essentially of pro~
pane, is recommended because of its ready
availability.
.
>
In order to more fully disclose the invention,
reference will be had- to »the accompanying
drawing, which is a flow diagram illustrating a
particular embodiment of the invention.
'
In the drawing II! represents the oil stock tank 1.5¢î
containing the oil which it is desired to treat, and
H indicates a suitable source of liqueñed pro
pane maintained under appropriate pressure..
The oil is drawn by the pump I2 and passedthrough charging line I3 into a. mixer I 4 and the>
propane is drawn by pump I5 and passed through
charging line I6 into the mixer I4. The charg
to a heating coil IT and
connected to a heating
stock and the propane, 25
ing line I3 is connected
the charging line I6 is
coil` I8 so that the oil
either or both, may be
desired temperature in
heated to maintain the
the mixer I4 and in a
settling tank I9 into which the mixer discharges.v
The heating coils I1 and I8 may be heated in
any appropriate manner, as by heat exchange 30
with products from the cracking operation, and
the mixer I4 and settling tank. I9 are preferably
insulated to retain heat and facilitate the ac
curate control of the temperature in the mixer
and settling tank.
By reason of the contacting of the oil and the 35
Solvent in the mixer and settling tank, asphaltic
constituents are precipitated out of the oil solu
tion and there is collected in the tank i9 a super~
natent oil layer and a bottom layer of asphaltic
material. The oil thus- freed of asphaltic ma»
terials flows into the cracking stock tank 20- andA
the asphaltic material is drawn into the asphalt
tank 2|. While the asphaltic material exists as
potential solid material, it is removed as a liquid 45
by reason of the fact that it is» in solution with a
certainv amount of the liquid propane and is with»
drawn to the asphalt tank. For purposes of sim
plicity, a single settling tank I9 is shown but it
is to be understood that it is often desirable to 50
employ a plurality of settling tanks to facilitate a '
better separation between the oil and the as
phaltic material.
The de-asphalted cracking stock collecting
in the tank 20„ may, if desired, be freed of pro-- 55 .
2,133,240
2
pane by reduction in pressure and the flashed
propane cycled to the propane tank H for re
use, or the cracking stock containing the propane
in solution may be passed directly to the cracking
zone. As illustrated, the pump 22 withdraws the
de-asphalted cracking stock from the tank 20 and
directs it to a cracking coil 23, positioned in a
furnace 24 adapted for supplying heat adequate
for cracking.
The coil 23 discharges into a
10 ~secondary cracking coil 25 positioned in a heat
ing or heat-retaining chamber 26 and a pump
of, for example, about 140° F. to 180° F. In prac
ticing the invention under somewhat less selec
tive conditions, while the oil may be substantially
freed of asphaltic constituents, there may be cer
tain proportions of oil constituents contained in
the solvent-asphalt mixture which will lower the
melting point.' The asphaltic material as re
moved from the oil by the action of the propane
and collected in the tank 2|, will be in liquid
form by reason of the presence of the liquid pro
pane (ordinarily about 50% of propane by vol
and sometimes due also to the presence of
21 withdraws asphaltic material from the tank . ume),
certain amount of oil constituents. The liquid
2| and introduces this material through line 2B asolution
of asphaltic material may be readily in
into the secondary cracking coil 25. The cham
jected into the stream of cracked products to l5
ber
26
may
be
supplied
with
furnace
gases
from
15
thereby accomplish the cracking of the as
the furnace 24 or otherwise heated under condi
phaltic, coke-forming constituents in an advan
tions of relatively low heat density. In lieu of
tageous way.
arranging the chamber 26 as an element sepa
The selective action of propane as a precipi
rate from the furnace 24 the heating coil 25 may
tating solvent for asphaltic material contained 20
be disposed in the furnace 24 in a Zone of rela
in hydrocarbon oil is exhibited at temperatures
tively low heat density therein. If desired, the of about 70° F. to about 150° F. An advantageous
asphaltic material being introduced into the coil temperature is 100° F. to 140° F. with volumes of
25 by the pump 21 may be preheated before be
ing admitted to the cracking coil, as by means of liquid propane of about three to ten to one vol
ume of oil. Under these conditions the action
25 a heating coil,29. In practicing the invention, of the solvent is highly selective in precipitating
the oil in the coil 23 is subjected to high cracking
asphalt with a minimum removal of oil. As the
temperatures under conditions of high cracking temperature
is raised increased proportions of
per pass and the stream of cracked products
flowing to the coil 25 is utilized in accomplishing oil will be contained in the solvent-asphalt mix 30
ture.
30 the cracking of the asphaltic material introduced
With ratios of propane to oil of as low as three
into the cracking coil 25.
to four to one at a temperature of 120° F. sub
The combined cracked products from the stantially all of the asphaltic material may be '
cracking coil 25 pass through transfer line 30 precipitated out from the oil. The de-asphalting
into a separator or vaporizer 3l wherein separa
is carried on under pressures appropriate for 35
35 tion of vapors from residue takes place. The sep
maintaining the solvent in liquid form under the
arated vapors are fractionated in fractionator 32
to separate as reflux condensate insuñìciently temperatures used and may well be carried on
under pressures of about 250 to 400 pounds.
converted constituents from vapors which are
condensed in condenser coil 33 and collected in
receiver 34 as a desired product. Reñux conden
sate collected in tower 32 is advantageously sub
jected to further cracking either by being cycled
to the cracking coil 23 or by being directed to a
separate cracking zone. In a preferred embodi
ment of the invention, the vapors in the tower
32 are subjected to a primary fractionation to
separate out a relatively small quantity of pri
mary reflux condensate which is collected at the
bottom of the tower 32 and a much larger pro
; portion of secondary reflux condensate collected
on a trap-out tray 35. This operation is advan
tageous in removing from the vapors certain
polymer products of cracking including certain
tarry or asphaltic products of reaction and the
>heavy reflux condensate containing these mate
rials is advantageously cycled by a pump 35 to
the oil stock tank I0 so that it may be admixed
with the charging stock for treatment with the
solvent. The secondary reflux condensate may be
cycled by a pump 37 to the cracking coil 23 or
it may be passed to a separate cracking unit not
shown.
The term “asphaltic material” as used herein
refers to certain black, pitchy material existing
' in the oil as a potential solid or semi-solid.
The
term is intended to apply to constituents having
a melting point of about 80° F. or higher. Or
dinarily in the treatment of crude petroleum re
siduum in accordance with the invention the
asphalt precipitated out, upon removal of the
solvent, will have a melting point of about 140°
F. to 180° F. In accordance with the invention
the solvent may be applied in a highly selective
manner to separate out an asphalt, which upon
removal of the solvent. may have a melting point
The solvent treatment may be employed to re
move from the oil, in addition to asphaltic con
40
stituents, certain resinous constituents. By re
moving the resins, as well as the asphaltic mate
rial, the treated oil is further improved as a
cracking stock with respect to coke-forming pro
clivities. '_I‘he resinous fraction may be removed
together with the asphaltic material, or if de
sired, the oil may ñrst be treated with the solvent
to remove asphalt and then further treated with
the solvent to remove the resins.
In the two
stage operation it is preferable to use a slightly 50
higher temperature for the resin-removing op
eration, thus for example with ratios of propane
to oil of 4-6z1 and with temperatures of about
13G-135° F. for the de-asphalting stage; tem
peratures of about 150°-1'75° F. may be used in 55
the de-resinifying operation. Both the asphal
tic and resinous fractions may be conducted to
the reaction coil 25 so that these materials may
be converted into lower boiling products.
The de-asphalted stock, either with or without 60
the removal of solvent, is passed to the cracking
coil 23 and subjected t'o relatively drastic crack
ing conditions therein to effect conversion into
gasoline constituents of superior anti-knock
quality. By way of example, it may be stated that 65
the deasphalted stock may be subjected to crack
ing temperatures of 900° F. to 1000° F. with a time
of reaction in the coil 23 adequate to effect a
conversion per pass (as measured by conversion
into 400° F. endpoint gasoline) of 20% to 30%. 70
The asphaltic material, and the resinous mate
rial and certain heavy oil constituents that may
be included with it, preferably after having been
preheated to temperatures, such as 600° F. to
800° F., is injected into the stream of cracked 75
2,133,240
products discharging from the cracking coil 23
to thus raise the asphaltic material to a high
Vcracking temperature, such as about 900° F., and
effect the cracking of the asphaltic constituents.
In this way the asphaltic constituents may be
subjected to a high rate of conversion tending
to the formation of gasoline constituents of su
perior anti-knock quality. The cracking opera
tion in the coils 23 and 25 is carried on under
superatmospheric pressure, such for example as
400 to 800 pounds, and the pressure on the cracked
products is preferably reduced in the evaporator
3| to facilitate the distillation of cracked products.
Appropriate reñuxing is carried on in the tower
32 to form a relatively small quantity of high
boiling reflux condensate which may contain
certain asphaltic or tarry products of reaction and
this heavy reflux condensate is advantageously
cycled to the oil stock tank I0. The lighter re
20 flux condensate collected on the trap-out tray
35 is subjected to further cracking as by being
cycled to the cracking coil 23 and the desired
gasoline product is collected in the receiver 34.
The ñXed gases from the receiver 34 or the
25 fixed gases obtained in rectifying the product
collected in 34, may advantageously be cycled to
the solvent storage tank Il to be mixed with the
solvent therein. In the operation in which the de
asphalted cracking stock passing to the tank 20
30 is not freed of its ñxed gas content, the fixed
gases contained in the oil passing to the cracking
coils 23 and 25 will undergo reversion reactions
therein so as to thus increase the conversion into
gasoline.
It is thus advantageous to cycle the
35 fixed gases, particularly the Cs’s and C-i’s, re
3
stream is at a cracking temperature to thereby
subject the asphaltic material to cracking.
2. In thev conversion of higher boiling hydro
carbon oil into lowerboilng hydrocarbons, the
process that comprises treating hydrocarbon oil
with a solvent of the oil under conditions in 'which
the solvent is an anti-solvent of asphaltic mate
rial to thereby precipitate asphaltic material con
tained in the oil, passing the treated- oil to a
cracking Zone wherein the oil is heated in a flow
10
ing stream to a cracking temperature and sub
jected to cracking, and introducing the asphaltic
precipitate into said flowing stream of oil at a
point therein at which the stream is at a crack
ing temperature to thereby subject the asphaltic 15
material to cracking.
3. In the conversion of higher boilng hydro#
carbon oil into lower boiling hydrocarbons, the
process that comprises treating a hydrocarbon
charging stock with a liquefied normally gaseous
hydrocarbon to thereby precipitate asphaltic ma
terial, passing the treated oil to a cracking Zone
wherein the oil is heated in a flowing stream
to a cracking temperature and subjected to
cracking, introducing the asphaltic preciptate 25
into said flowing stream of oil at a point therein
at which the stream is at a cracking temperature
to thereby subject the asphaltic material to
cracking, separating the resultant cracked prod
ucts into vapors and residue, fractionating the 30
separated vapors to form a heavy reilux con
densate, an intermediate condensate and a final
distillate product, and combining the heavy re
flux condensate with the charging stock for
treatment with said liquefied normally gaseous 35
moved from the final distillate of the process, to
hydrocarbon.
the solvent tank Il so as to obtain not only the
solvent value of the gases in the asphalt re
moval step but also to increase the reversion
4. In the conversion of higher boilng hydro
carbon oil into lower boilng hydrocarbons, the
process that comprises treating a hydrocarbon
charging stock with a liquefied normally gaseous 40
hydrocarbon to thereby precipitate asphaltic ma
v40 reactions occurring in the cracking zone.
While I have described a particular embodi
ment of my invention for purposes of illustration,
it should be understood that various modifications
and adaptations thereof which will be obvious to
45 one skilled in the art, may be made within the
spirit of the invention as set forth in the appended
claims.
I claim:
1. In the conversion of higher boilng hydro
50 carbon oil into lower boiling hydrocarbons, the
process that comprises treating hydrocarbon oil
with a liqueñed normally gaseous hydrocarbon
to thereby precipitate asphaltic material, passing
the treated oil to a cracking zone wherein the oil
55 is heated in a ñowing stream to a cracking tem
perature and subjected to cracking, and intro
ducing the asphaltic precipitate into said flowing
stream of oil at a point therein at which the
terial, passing the treated oil to a cracking zone
wherein the oil is heated in a flowing stream to
a cracking temperature and subjected to crack
ing, introducing the asphaltic precipitate into 45
said flowing stream of oil at a point therein at
which the stream is at a cracking temperature to
thereby subject the asphaltic material to crack
ing, separating the resultant cracked products
into vapors and residue, fractionating the sepa
rated vapors to form a heavy reflux condensate, 50
an intermediate condensate and a ñnal distillate
product, subjecting the intermediate condensate
to further cracking and combining the heavy re
flux condensate with the charging stock for
treatment with said liquefied normally gaseous 55
hydrocarbon.
.
'
HAROLD V. ATWELL.
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