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Патент USA US2105526

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Jam.l 18, 1938.
2,105,526
c. P. DuBBs PROCESS OF HYDROCARBON OIL ‘CONVERSION
original Filed March 23, 1925
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2,105,525
Patented Jan. 18, 1938
UNITE
STATES PATENT OFFICE
2,105,526
PRÜCESS 0F HYDROCARBON OIL CONVER
SION
Carbon P. Dubbs, Wilmette, Ill., assignor to Uni
versal Oil Products Company, Chicago, Ill., a
corporation of Delaware
@riginal application March 23, 1925, Serial No.
17,516. Divided and this application Decem
her 3, 1932, Serial No. 645,523. Renewed Sep
ternher 17, 1936
5 Claims. (C1. 196-48)
This application is a division of my application charged through the transfer line I0, in which
Serial No. 17,516 filed March 23rd, 1925.
This invention relates to .improvements in a
method of hydrocarbon oil conversion and refers
more particularly to the treatment of hydrocar
bon oils under conversion temperature and a
substantial super-atmospheric pressure to pro
duce light fractions therefrom suitable for com
mercial use.
The particular embodiment of the present in
vention resides in passing a stream of hydrocar
bon oil through an elongated passageway, for in
stance, a continuous coil, mounted in a furnace,
where the oil is heated to substantially a con
version temperature while being maintained un
der a super-atmospheric pressure. This heated
oil is then discharged into an enlarged reaction
chamber, where substantial separation of the
lighter fractions in the form of vapors will take
20
place, said vapors being dephlegmated, condensed
and collected in a receiver as distillate. This in
vention contemplates that regulated portions of
said distillate are to be returned from the re
ceiver to the stream of oil heated in the elon
gated passageway and mixed therewith, either
at the point of introduction of said stream of
oil to the elongated passageway, or after said
stream has passed through the elongated pas
sageway and been heated and while it is being
transferred to the reaction chamber.
Various advantages of the invention will ap
pear more fully from the following description.
The single ligure in the drawing is a diagram
matic flow sheet of a commercial form of ap
ll.) paratus in which the process may be carried out.
Referring in detail to the drawing, the raw
oil is withdrawn from the supply tank I and
passed through the line 2, in which is interposed
the raw oil pump 3, this line 2 communicating
with the lines 4 and 5. The line 4 has valve 5
interposed therein and discharges the raw oil
into the top of the dephlegmator 1. Instead of
discharging into the top of the dephlegmator 1,
the raw oil may be passed through the line 5,
in which latter is interposed the valve 8, said line
5 communicating with the inlet side of elongated
passageway 9, which may comprise a continuous
coil of say 3 or 4 inch pipe, mounted in a suit
able furnace. The feed of raw oil may be split,
that is, part may be fed directly to the dephleg
mator and part directly to the inlet side of the
heating coil 9,
The raw oil, in its passage through the heat
ing coil 9, has its temperature increased and is
brought to a conversion temperature, and is dis
is interposed valve II, to the upper portion of
the enlarged reaction chamber I2, which reac
tion chamber may be vertically disposed, as
shown. The reaction chamber I2 is provided
with upper and lower manholes I3 for the pur
pose of cleaning, and this chamber may be insu
lated if desired. In the normal operation of the
process, it is preferably unheated. The lighter
fractions of the heated oil being introduced 10
through the line I0 will vaporize and be dis
charged from the upper portion of the reaction .
chamber I2 through the vapor outlet line I4,
in which is interposed valve I5, said line I4 com
municating with the lower portion of the de
phleginator 1. Superimposed in the interior of
the dephlegmator 1 are a plurality of horizontal
pans or baffles I6, which need no particular de
scription, as they are standard in commercial
practice. The vapors passing upwardly through 20
the dephlegmator are retarded in their travel in
order to condense any of the heavier fractions.
The raw oil introduced through the line 4 acts
partly as a cooling medium for this purpose.
The vapors remaining uncondensed after 25
coursing upwardly through the dephlegmator 1
are discharged into the vapor outlet line I1, in
which is interposed valve i8, said line I1 com
municating with the condenser coil I9, which,
of course, is mounted in the usual condenser box, 30
not shown. The discharge end of the condenser
coil has a valve 20 interposed therein and com
municates with the receiver 2I, which receiver
is, of course, equipped with the usual sight-glass
gauges, pressure gauge, and with the incondens 35
able gas outlet 22 controlled by valve 23 and
liquid discharge 24 controlled by valve 25.
The unvaporized residue from the reaction
chamber I2 is withdrawn through the residue
drawoff line 26, in which is interposed valve 21 40
communicating with the cooling coil 28, and dis
charging the cooled residue into the line 29, in
which is interposed the valve 30, to a residue
storage 3l. As the separation of lighter frac
tions takes place within the reaction chamber I2, 45
carbon will be released and will gradually ac
cumulate on the bottom and build up in the in
terior of said chamber. It may then be neces
sary to withdraw the unvaporized residue at
various heights from the reaction chamber, and '
of course the single line 26 is purely diagram
matic.
Referring now to the important features of the
present invention, portions of the distillate col
lected in the receiver 2_I are withdrawn into the
2,105,526
2
line 32, in which is interposed valve 33, by means
of the suction imposed by the pump 34, the `dis
charge side of said discharge pump 34 discharg
ing the distillate into the line 35. Said line 35
communicates with the receiving end of the
transfer line il! by means of the connection 36, in
residue unmarketable for fuel. I have discovered
that by increasing the percentage of gasoline or
light gravity cracked oil to the uncracked oil as
it passes through the heating coil 9, and before
discharging into the reactionV chamber, that this CII
increased percentage of gasoline or light gravity
which is interposed valve 3l, or said distillate
may be by-passed through the line 38 in which is
sive amount of this pitchy matter in the residue.
interposed the valve 39, introducing said distil
late into the stream of raw oil and reflux being
passed into the inlet side of the heating coil 9.. A
drain dll, having a valve 4I, may be provided ad
jacent the inlet to» the coil 9.
The reflux condensate produced in the de
phlegmator 'l and the unvaporized raW oil are
Withdrawn from the dephlegmator l through the
reflux line 42, in Which is interposed Valve 43,
and passed to the hot oil pump 44. The discharge
side of the hot oil pump 44 discharges the mix
ture of reflux condensate and unvaporized ravv
oil into the line 45, in Which is interposed the
valve 4t, said line 45 communicating With the
line 46 going to the heating coil 9. In case it is
not desirable to impose an applied pressure on
the mixture of raw oil and reflux condensate be
ing withdrawn through the line 42, a by-pass 4l
is provided, controlled by valve 48, it being under
stood that when the mixture is passed through
the line 4l, valve 48 is opened and valves 43 and
30 46 closed, and vice versa.
The particular utility and reasons for return
ing regulated portions of the distillate from the
receiver 2I and mixing said portions with the oil
being heated before it is discharged into the re
35 action chamber, will be noW set forth.
For illus
tration, a 24° Baumé gravity fuel oil made from
Mid-Continent Crude is treated in the plant and
produces 30% Navy initial and end point gasoline.
The capacity of the plant will be 700 barrels with
40 out the hot oil pump 44 and say 1000 barrels of
raw charging stock per day with the reflux pump
44. The entire plant may be operated at 170
pounds pressure per square inch and the oil as
it leaves the heating coil 9 Will be at a tempera
45 ture of say about 860° F.
Sixty percent of the raw oil fed into the plant
Will be converted into pressure distillate, 501% of
Which pressure distillate will be gasoline and the
remainder will be pressure distillate bottoms or
50 gas oil. The unvaporized portion in the reaction
chamber I2 Will be a residue representing about
35% of the raw oil treated and will have a
gravity of say 18° Baume. This unvaporized
residue Will contain in suspension considerable
55 pitchy matter and only part of this pitchy matter
held in suspension will settle out upon standing.
This pitchy material seems to be in a more or
less colloidal condition in the residue.
From my experience, I believe that this pitchy
60 matter is made up of carbon in a very ñnely di
vided state, Which carbon mechanically com
bines With the heavy ends of the oil, and the
combination is so strong as to resist the oil at
tracted to the carbon from becoming dissolved
65 in the remainder of the oil, floating in the oil as
a scum which seriously interferes With the oil
being used as fuel on account of the fact this
scum Will clog the pipes and burners of the fuel
system.
70
Operating the plant so as to increase the yield
of gasoline increases the amount of this pitchy
matter, which stays in suspension in the residue,
and as the residue to be marketable as fuel oil
cannot lcontain over a certain amount of sedi
ment, this suspended pitchy matter renders the
cracked oil prevents the formation of an exces
At the present time, I do not fully understand
how this formation of an excessive amount of
pitchy matter is prevented, but it is my opinion
that part of the carbon produced from cracking
unites mechanically with the heavy ends of the
oil and forms a pitchy matter Which remains
suspended in the oil. Therefore, that oil in 15
which the pitchy matter is suspended does
not have the power to break down the at
traction of the carbon to the heavy ends and
cause the heavy ends to go into solution and thus
20
precipitate the carbon.
I do find that When I increase the percentage
of gasoline or light gravity cracked oils to the
total oil flowing from the coil 9 to reaction cham
ber I2, that I decrease the amount of this pitchy
matter held in suspension in the oil with the car 25
bon and by regulating the increase, I can practi
cally prevent any substantial amount of carbon
mechanically combining with the heavy ends of
the oil to form a pitchy suspended matter in the
residuum. I have also discovered that the 30
amount of free carbon accumulating in the re
action chamber per barrel of gasoline produced
is decreased by increasing the amount of gaso
line or light gravity oil Contained in the oil as
it is transferred to the reaction chamber.
For 35
example, an oil producing normally about 40
pounds of carbon per barrel of gasoline produced
'can be so treated as to produce only about 30
pounds of carbon per barrel of gasoline produced.
As a further illustration of my invention, in 40
operating the plant there is fed 500 barrels of raw
oil through the elongated heating tube 9, and
at the same time there is fed 2000 barrels of re
flux tothe heating tube 9, making a total of
2,500 barrels of oil passing through the tubes and
discharging into the reaction chamber every 24
Of this total, 2,300 barrels Will be va
' hours.
porized in the reaction chamber, passing into the
dephlegmator through the vapor line Iii. Ap
proximately 2,000 barrels are condensed in the .
dephlegmator and returned to the heating coil
9 mixed With a fresh supply of oil, as heretofore
described. The remaining 300 barreis will dis-J
charge as vapor from the top of the dephlegma
tor and will be collected in the pressure distillate
receiving tank 2l, after being condensed in the
condenser coil I9. This 300 barrels of pressure
distillate contains approximately 150 barrels of
gasoline, which is 30% of the 500 barrels of raw
charging stock used, but is only 6% of the 2,500 (10
barrels of oil passed through the heating tube 9.
In order to enrich the amount of gasoline or
cracked oil to the total amount of oil passed
through the heating tube 9, there are passed 500
barrels of raw charging stock and 500 barrels of
reflux through the heating tube 9, making a total
of 1000 barrels going through the heating tube
and into the reaction chamber. Approximately
800 barrels of this amount pass to the dephleg
matcr l as vapor through the line I4, 500 barrels 70
of which are condensed in the dephlegrnator and
returned to the heating tube 9, mixing with an
other 500 barrels of fresh charging stock. The
remaining 300 barrels pass out of the top of the
dephlegmator in the form of vapor and are even
2,105,526
>tually collected in the pressure distillate receiver
and come out in the form of distillate, this 300
»barrels containing approximately 150 barrels of
gasoline. The 200 barrels remaining unvapor
ized in the reaction chamber may be withdrawn;
as residue.
In the above illustration, the 150 barrels of
.gasoline produced comprises 30% of the raw oil
treated, but is 15% of the 1000 barrels of oil
passing through the heating tube 9 and into the
reaction chamber i2. By comparison with the
run set forth above, it will be seen that I have
doubled the percentage of gasoline produced in
the oil passing through the heating tube.
15
Now I can still further increase these relative
percentages by passing 500 barrels of oil directly
through the heating tube 9 and discharge same
into the reaction chamber I2, withdrawing from
said reaction chamber 200 barrels as residue and
300 barrels as vapors, which pass through the
dephlegmator, all of said 300 barrels going over
into the pressure distillate receiver tank, and
therefore, no reñux being furnished to the oil
flowing through the heating tube 9. In this case,
it will be seen that the gasoline produced is not
only 30% of the raw oil treated, but is 30% of
the amount of the oil passed through the heating
tube 9, or ?lve times the amount of gasoline com
pared with the first operation above described.
This latter operation, however, will cause the
heating tube 9 to become seriously congested with
carbon unless the pressure is increased in pro
portion, which of course, makes the pressure ex
tremely high.
Another method oi accomplishing the same
result is to feed 300 barrels of raw oil into the
plant and have 700 barrels of reñux, making a
total of 1,000 barrels passing through the heat
ing tube 9 and discharging into the reaction
chamber. One hundred barrels of unvaporized
residue may be withdrawn from the reaction
chamber and 900 barrels of vapors passed to the
dephlegmator, of which 900 barrels '700 barrels
are condensed and refiuxed back' to the heating
tube 9, as heretofore described, the remaining
200 barrels discharging from the top of the de
phlegmator as vapors and condensed and col
lected in the pressure >distillate receiver 2l, this
200 barrels containing approximately 150 barrels
of gasoline, which comprises 50% of the raw oil
passed into the plant, but 15% of the total oil
passed through the heating tube 9. It will be
noted that this 15% is more than twice the
amount produced on the basis of oil cracked,
as compared with the first operation above de
scribed.
The plant described in the flow chart is based
on the principle that at a given pressure, the
00
maximum of the cracking of oil passing through
the heating tube 9 is limited below that amount
of cracking that will cause a substantial deposit
of carbon in the heating tube 9. This maximum
can be increased to a certain extent by increas
_ ing the pressure under which the plant is operat
gasoline and thus avoid excessive deposits of car
bon in the heating tube 9.
I now seek to increase the percent of gasoline
o-r similar cracked products and at the same time
prevent excessive formation of pitchy matter in 5
the residue and produce less coke per barrel of
gasoline produced. I have already described how
this percentage of gasoline can be increased by
increasing the pressure, but the amount of pres
sure increase is, of course, limited, and there may
be objections to high pressures. Therefore, in
order not to violate any of the principles in
volved in a successful operation of the cracking
plant as above deñned, I have discovered that
by increasing the percent of gasoline or light
gravity cracked oil in the oil passing through
the heating tube, these results .can be accom
plished. Therefore, I add distillate or light grav
ity cracked oil to the stream of heated oil which
is to be discharged into the reaction chamber,
either before it is passed through the heating
tube 9 or after it is passed through the heating
tube 9 and before discharge into the reaction
chamber. Said distillate or light gravity oil is
added in such proportion as to substantially pre
vent the formation of pitchy matter in the resi
due, and these proportions will, of course, vary,
not only with the character of oil being treated,
but with the manner in which the regular opera
tion is carried out.
30
A by-pass 49 controlled by valve 50 is provided
in the line 32 in case it is not necessary to use the
pump 34, valves 5| and 52 being closed in this
event. By my invention, I ñnd I am able to
obtain high yields of gasoline, even when cracking
fuel oil, and at the same time produce therefrom
a residue containing only a very low percentage
of pitchy matter in suspension, which residue is
marketable for fuel. In addition, I find that
there is produced less solid matter per gallon of 40
gasoline produced.
It is of course, understood that the stream of
distillate may be split and part introduced
through the line 35 into the mixture flowing
through the transfer line l0, and part being in 45
troduced through the line 38 into the mixture
feeding toward the heating tube 9 through the
pipe 46.
I have disclosed the idea of returning portions
of the pressure distillate from the receiver 2|. 50
It is, of course, obvious that the gasoline or other
lighter gravity oil may be introduced from any
source of supply and need not be the distillate
produced in the operation.
A preheater 53 having valves 54 introduced ‘
therein may be connected into the line 35, the
valve 55 in line 35 being closed. The use of the
preheater is, of course, optional. The operator of
the plant may ñnd it desirable when treating cer
tain oils under certain conditions to preheat the 60
lighter gravity oil. ’I‘he degree of heating will
be governed by conditions surrounding the opera
tion. In other Words, it may be advisable to pre
heat the lighter gravity oil only slightly, that is,
below the temperature of the oil discharging from
the outlet end of the coil 9, or it may be advan
ing and also the velocity at which the oil passes
through the tube. Having established this prin
ciple, I increase the yield of low boiling point . tageous to heat same to or just below the temper
products by keeping at or below the maximum
percentage of cracking in each pass of the oil
through the heating tube 9 and then separate
from this oil the uncracked portion, returning
same to the tube for further heating, this oper
ating cycle being repeated until the desired per
centage of the total oil has been converted into
ature at which the oil passing through the coil 9
is discharged, in order that no appreciable cool
ing of the oil heated in the coil 9 will take place
in the transfer line I0, and yet preventing any
substantial decomposition of the lighter gravity
oil such as the distillate heretofore referred to
into ñxed gas. When the distillate is introduced
75
2,105,526
4
Vthrough-the pipe 38, the valve 3l being closed,
the oil is preferably not preheated.
Regulated portions of the lighter gravity oil
may be introduced to the reaction chamber
through the connecting line. 5S, valve 51 con
trolling said introduction. This pipe 56 may dis
charge at any height into the reaction chamber.
As another method of operation, regulated por
tions of the vapors discharging from the top of
the dephlegmator may be diverted through the
line 5S, lcontrolled by valve 59, and forced by
means of pump 60 interposed in said line 58 to
' the transfer line Iû, or to any point in the heating
tube 9 which may be found desirable. Vapors may
be. diverted in this manner either with or without
the return of -any liquid distillate and with or
Without the introduction of any other lighter
gravity oil in case the distillate is not utilized for
this purpose.
I claim as my invention:
l. A cracking process which comprises passing
hydrocarbon oil in a restricted stream through a
heating zone and heating the same therein to
cracking temperature under pressure, discharg
ing the hot oil stream into an enlarged reaction
zone maintained under cracking conditions of
temperature and pressure, removing vapors from
the reaction zone and dephlegrnating the same to
condense insufficiently cracked fractions thereof,
'30 returning resultant reflux condensate to the heat
ing zone, combining a gasoline-containing por
tion of the dephlegmated vapors with the hot oil
stream discharging from the heating Zone to the
reaction Zone, finally condensing the remaining
portion of the dephlegrnated vapors and intro
ducing a portion of the resultant distillate into
the reaction zone at a point remote from the
point of discharge of the hot oil stream thereinto.
2. A cracking process which comprises passing
hydrocarbon oil in a restricted stream through a
heating zone and heating the saine therein to
cracking temperature under pressure, discharging
the hot oil stream into the upper portion of an
enlarged reaction zone maintained under crack
ing conditions of temperature and pressure., re
moving vapors from the reaction Zone and de
phlegmating the same to condense insuinciently
cracked fractions thereof, returning resultant re
flux condensate to the heating Zone, combining a
portion of the dephlegmated vapors with the hot
cracking temperature under pressure, discharg
ing the hot oil stream into an enlarged vertical
reaction vzone maintainedv under cracking condi
tions of temperature and pressure, passing the
unvaporized oil downwardly through the enlarged
zone and removing the same. from the lower por
tion thereof, removing vapors from the reaction
zone and dephlegmating the same to condense
insufficiently cracked fractions thereof, subject
ing the dephlegmated vapors to further condensa 10
tion to form a gasoline-containing distillate,
passing a gasoline-containing portion of said dis
tillate through a second heating zone and heat
ing the same therein sufficiently to prevent cool
ing of said hot oil discharged from the first-men
tioned heating Zone upon commingling therewith,
and then discharging the thus heated distillate
directly into the lower portion of the reaction
Zone to commingle with the unvaporized oil
therein.
4. A cracking process which comprises heating
hydrocarbon oil to cracking temperature under
pressure while flowing in a restricted stream
through a heating zone, subsequently discharg
ing the heated oil into the upper portion of an
enlarged separating zone and separating the
same therein into vapors and unvaporized oil,
fractionating the vapors to condense heavier
fractions thereof and to form a gasoline-contain
ing distillate, passing a gasoline-containing por- ‘
tion of said distillate through a second heating
zone and heating the same therein sufficiently
to prevent cooling of said heated oil upon com
mingling therewith, and then discharging the
thus heated distillate directly into the lower por- "
tion of the separating zone to commingle with
the unvaporized oil therein.
5. A method of hydrocarbon oil conversion,
consisting in passing a stream of hydrocarbon oil
through a continuous elongated passageway, 40
Where it is heated to a conversion temperature,
maintaining a substantial super-atmospheric
pressure on the oil, discharging said heated oil
into an enlarged zone where substantial separa
tion of lighter fractions in the form of vapors
will take place, separately withdrawing the vapors
and subjecting them to dephlegmation, in con
densing portions of the uncondensed vapors after
dephlegmation and collecting them as liquid dis
tillate, returning regulated portions of the vapors
oil stream discharging from the heating zone to
the reaction zone, finally condensing the remain
ing portion of the dephlegmated vapors and in
without substantial condensation and mixing
troducing a gasoline-containing portion of the'
resultant distillate into the lower portion of the
heated oil prior to discharge into the enlarged 55
reaction zone.
3. A cracking process which comprises passing
hydrocarbon oil in a restricted stream through a
heating zone and heating the same therein to
them with the heated oil prior to discharge into
the enlarged zone, also returning and mixing
regulated portions of the liquid distillate with the
zone for the purpose of increasing the percentage
of lighter fractions in said oil.
CARBON P. DUBBS.
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