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Патент USA US2108395

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Feb. 15, 1938'. >
Filed Dec. 30, 1933
> . 2 Shgets-Shect 1
?ederzck WSaZZwazzJr
Feb. 15, 1938.
2 Sheets-Sheet 2
Filed Dec. so‘, 1933
mu .0\\
L . Patented Feb.'~.l5,“ 1938
_ " ‘2,108,395; v
' Frederick W. Sullivan, Jrl, Hammond, Ind., as
‘signor to Standard Oil Company, Chicago, 111., I
of Indiana
vApplication(December 30, 1933, Serial No. 704,773'
6 Claims. "(01. 196-9)
vMy-invention relates to an improvementin the art of hydrocarbon conversion processes or in 1200° F. while under pressure of 750 to 3000 lbs. '
other words, to an improved process for the con- _ per sq. in. Cracked products, which may or may
version of hydrocarbon gas and relatively heavy not be passed through a soaking drum, go to an
hydrocarbon oils to relatively light oils of the evaporator or‘ separator maintained at relatively
low pressure where tar and asphaltic materials 5
‘gasoline‘boiling range.
eliminated. The overhead products from the
The commercial development of present day -' are
evaporator are passed to a conventional bubble
oil cracking processes has been-long andcom
plex but has been characterized by relatively ‘tower which may operate at the same or lower
10 few radical changes'in the types of processes. pressure as the evaporator and from which gaso
First were the simple bulk distillation processes line is eliminated as an overhead product. Heavy 10
gas oil is‘ eliminated from the bottom of the
wherein relatively clean virgin charging stock
bubble tower but this is not cycled in the conven
manner to the cracking step, although a
, I distilled under pressure until the residue in the
part thereof may be returned to the process (sub.
15 still became too heavy for ~_further heating with-' sequent
to the heating system) as quenching oil. 15
out danger of coking. The next development was Light gas
oil may be likewise eliminated from
the Burton-Clark type of batch or semi-continu- '
ous process wherein, the contents of the still were an intermediate point‘ in the bubble tower and a
part of this may be recycled to the cracking
circulated through a tube heater instead of ap
was introduced into a direct-?red shellstill and
20 plying direct heat to the shell still. Then came
processes of the tube or tube and‘ drum type
step whilev another part, or substantially all there
of, may be utilized as quenching oil.
The degraded gas oil, or the balance thereof,
with "clean circulation” wherein the return of' which
may have a density of 25_-30° A. P. I., is
any heavy asphaltic cracked material to the then' passed
to a high temperature low pressure
heating section of the system was prevented.
wherein it is cracked substantially
25 All of these processes, however, use the‘ prin
ciple of recycling, i. e., of recirculation of all or completely to gases and. heavy tarry or car- 25
a substantial proportion of the insu?iciently bonaceous materials. ‘This step may be carried
out in a pipe heater or in any other suitable
cracked material to theheating and reaction sys
of high temperature cracker. Following
‘tem; Once-through processes have been pro
suitable separation steps, the ole?nic gas from
,30 posed, and used to a certain extent commercially, the
high temperature low pressure cracking step 30‘
but were'never ‘successful on a commercial scale is recycled to the inlet of the initial high pres-'
‘ - on account of the relatively low yield of gasoline
sure cracking step. Selected portions of'the gas
which was possible by such processes.
' , from the main cracking system may be joined
I have discovered that by the use of elevated with the gas oil therefrom prior to the high
35 temperatures and pressures, i. e., higher tem
temperature low pressure cracking step. The 35
peratures and pressures than those normally used . '
~ in commercial cracking processes, and by the
' use of a selected charging stock I‘ may eliminate
substantially all recycling ‘and nevertheless‘ ob
40' tain av high yield of gasoline. My particular dis
high temperature cracking step is preferably op-‘
erated at temperatures of 1000°-1700° F. while
under pressure of 0-200 lbs. per sq. in. above at
The ole?nic gases of the high temperature 40
covery is that such a process can be operated
economically on a commercial scale by separat . cracking step undergo polymerization‘ and inter
action with fresh oil charged to the initial crack
ing the unconverted or insuiiiciently cracked ma
terial from the one -through reaction products
45 and cracking the majority of said unconverted
material- to gases of an ole?ni'c character, which
,gases- are then recycled to ‘the initial ‘cracking
step where polymerization and condensation to
gasoline occurs. The operation of my process is
$0 as follows:
ing step whereby greatly increased yields of gaso
line are obtained, as compared with the ordinary
once-through operation.
The foregoing represents a brief summary of
my improved ‘process, the full and complete de—
scription of_ which is as follows:
In the drawing attached hereto and forming
I utilize a selected-charging stock, preferably . a part of this speci?cation,'Fig. 1 is a diagram- 50
‘gas oil of approximately 35° A. 1?. I. gravity which matic elevational view of suitable apparatus for
carrying out my process in one embodiment
contains substantially no previously crackedtma
. terial.v In the initial cracking step the fresh thereof, and Fig. 2 ‘is a similar view of apparatus
i5 charge is subjected to temperatures of 950,
. for carrying out my process in analternative ,
embodiment thereof.
The fresh oil charging stock’ is introduced into
the system through line I0 by pumping means
not shown. As charging stock I use a gas oil of
approximately 30‘? to 40° A. P. I. gravity but may
use somewhat lighter or heavier stock, depending
or I9 to serve as quenching/oil as previously de
scribed, or part may be passed through valve
31 and 31a in line 38 into evaporator |5 to serve
in .part on the characteristics of the crude oil
Bubble tower 30 may also be provided with
trap-out tray 4| from which light gas oil may be
withdrawn through line 42. This light gas oil
may be further treated as later described, but 10
part thereof may be pumped by pump 43 through
valve 44 and cooler 44b and returned to tower 30
as re?ux or part may be passed through valves
- from which the stock is derived. I preferably use
virgin or uncracked gas oil, i. e., a distilled frac
tionlfrom crude oil containing substantially no
10 heavy asphaltic constituents.
The charging stock after preheating by suitable
" heat interchange means not shown is introduced
into the coils of heater || wherein it is heated
as cooling medium therein, or may be returned
through valve 39 in line 40 to serve as re?ux and
cooling medium in bubble tower 30.
to temperatures of 950°-1200° F. while under- pres
sures of 750-3000 lbs. per sq. in. The time of con
tact in heater I l is ordinarily short, although
heater |l may be provided with a soaking section.
I may also make use of an unheated soaking drum‘
|2 following heater II. If no soaking drum is
20 used, the heated products from heater || pass
directly through line i3 and valve l4 to evapo
rator l5, the pressure being reduced at valve l4
to the desired evaporator pressure, which in gen
eral will befrom 50 to 250 lbs. per sq. in. I'may
25 also introduce relatively'cool quenching oil from
a suitable source (as later described) through
line i6 and through valve l1, thus introducing
the quenching oil just ahead of reducing‘ valve M,
or may introduce the quenching oil through valve
30 l8 located just following valve l4.
\ '
If soaking drum I2 is used, valve I4 is closed
and valves |8a and l8b- are opened in which case
valve |8b functions as the pressure‘ reducing
valve for bringing the pressure down to the de
35 sired evaporator pressure. In this case I may
introduce. quenching oil from line l9 through
valve 20 located just ahead of valve lab or through
valve 2| located just subsequent to valve lab.
I may also introduce all or apart of the desired
quenching oil through line l6 and valve 22, which
is located ahead of the soaking vdrum l2 whereby
somewhat lower temperatures of 900°—l050° F. are
maintained in the soaking drum II. If the soak
ing drum is used ‘the hot cracked materials
45 therefrom pass through line 23 to evaporator I5.v
45 and 45a in line 46 to pump 41 and admixed
with fresh charging stock from line H] prior to
entering heater | I. A part of the oil from line 46
may also be passed through valve 48 and cooler
49 to lines It or I9 to serve as quenching oil as
previously described.
_ The vapors from bubble tower 30 are con
densed in condenser 50 and passed through pres
sure regulating valve 5| into gas separator 52
which is ordinarily operated at essentially the
same pressure as bubble tower 30 so that a rela
tlvely “dry” release gas may be separated through 25
line 53 and eliminated from the system, or uti
lized, as later described. Condensed light prod
ucts are removed from separator 52 through
line 54 and may be withdrawn from the system
through valve 55. I may, however, provide my 30
system with a gasoline stabilizing tower in which
case the condensed light products from line 54
‘pass through line 56 to stabilizer 51 which is
provided with suitable reboiling means and re
flux means whereby stabilized gasoline free from 35
undesirable ‘light constituents is ‘withdrawn
through bottom offtake 58 while a relatively rich
stabilizer gas is‘ eliminated overhead to line 59
and is withdrawn from the system by valve 60,
or otherwise utilized as later described.
I The unconverted gas oil withdrawn from bub
ble tower 30 through line 33 is passed through
line BI. and pump 62 through low pressure high
temperature heater 63. I may also pass any part
of light gas oil withdrawn from tower 30 by line 45
‘42 through valve 63a and thus to heater 63.
In evaporator I5 9. pressure of 50-250 lbs. per Heater 63 is operated at temperatures of 1000
sq. in. is maintained and the temperature is‘ regu- ‘ 1700” F. and pressures of 0-200 lbs. per sq. in.
lated by suitable cooling means to separate sub
above atmospheric wherebythe gas oil is cracked
stantially all heavy tarry materials which are substantially completely into gases of high ole
removed by drawoff 24. These tarry materials ?n content plus heavy tar and carbonaceous ma
may be eliminated from the system, or a part terials. Heater 53 may be of ordinary pipe heater
thereof‘ may be pumped by pump 25 through cool
construction as illustrated, or may be of any
er 26 and passed into line l9 or line I6 to serve as
other suitable construction, i. e., such as a re
~quenching oil as previously described, or part ' fractory checkerwork which is alternately heated
55 thereof may be passed through valve 21 in line by ‘direct combustion, etc. I may also withdraw
28 thus being returned to evaporator l5 to act a part of the release gas from separator 52 and
as a cooling medium therein. Evaporator l5 may
also be cooled by heat interchange coils with
fresh charging stock orbyiother suitable means.
60 Following evaporator |5 uncondensed vapors pass
through line 29 to bubble tower 30. The pressure
in bubble tower 30 may be the same as in evapo
rator l5 or may be regulated at some lower pres
line 53 through valve 64 in line 65 and introduce
same by pump 66 into heater .63 in admixture
with gas oil'charged thereto. I may also pass 60
all or a part of the stablizer gas from stabilizer
51 and line 59 through valve 61 in line 68 to line
65 and pump 65 for admixture with oil charged
sure by means. of valve 3| in line 29. The oper
65 ation of bubble tower 30 is conventional. Vapors
to heater 63. If gas is admixed with oil charged
to heater 63 I preferably preheat the gas by 65
heating or heat interchange means not shown,
oiftake 32 and unconverted gas oil is drawn off
at the bottom of the tower through line 33. Suit
able cooling means are provided which may in
70 clude coils for heat interchange with fresh
zation is promoted. This admixture of gas~with
the oil charged to heater 63 not only facilitates
operation of the heater by providing more com 70
plete vaporization of the charge, but also serves
of desired light products are removed through
charging stock. The gas oil is withdrawn through
line 33, and is withdrawn from the primary crack
ing system and utilized as later described, but a
part thereof may be pumped by pump 34 through
75 cooler 55 and passedthrough line 35 to lines l6
prior to admixture with the oil whereby vapori
as an additional source of material from which
gaseous olefins may be obtained.
Products from heater 63 are passed through
line ‘69 to a suitable separator 10 which is pro 76
vided with suitable cooling means, not, shown,
and from which tar and carbonaceous materials
are removed through drawo? ‘II while gases and
.vapors pass through line 12 to cooler 13 and
thence through valve 14. to separator 15 wherein
condensed light oils (which are formed to a small
extent in - heater 63) are withdrawn through
valve 16 while high‘ole?n content gases are re-'
moved through line ‘I1 and valve 18 for use as
‘10 later described.
I may also operate separator ‘I5 at a somewhat
elevated pressure in which case valve ‘His closed
and valves 19 and 80. are opened wherebythe
._ materials ‘from cooler 13 may be compressed to
15 a suitably elevated pressure of 50-1000 lbs. per
able fresh charging stock, I may operate my proc
ass in two once-through high pressure-high tem
perature stages before eliminating unconverted
material and cracking same to ole?nic gases for
recycling. Ordinarily -I use this type of “dual
once-through” process if the charging stock grav- ,
ity is in the upper part 01' the range which I have
previously disclosed as most suited for my process
or, in other words, if the charging stock has a
gravity of approximately 35° A. P. I, to 40° A. P.
1., although slightly lower or higher gravities may
be permitted in some cases depending on the dis
,tilla'tion range of the charging stock and on its
chemical characteristics, which latter are in gen
eral determined by the crude oil from which it is .15
sq. vin. by pump 8i.’ Under these conditions the Vobtained. In this "dual once-through” modi?
‘gas separated in separator 15 will consist pri
cation of my process the apparatus used is es
f , marily of methane and hydrogen which may ‘be .sentially identical with that shown in the at
eliminated from the system through valve 82. tached ?gure except that the gas oil eliminated
20 If the light oils present in separator 15 are not
from bubble tower 30 through lines 33 and 4-2
su?icient in volume ‘to e?ect this scrubbing and (except that part. thereof which may be used as
separation of methane and hydrogen from other quenching oil or recirculated for re?ux and cool- ‘
. desired gases, I may add additional scrubbing
ing purposes) is passed to a second high pres
‘oil (through means not shown) to separator 15 sure-high temperature heater identical with
25, whereby this purpose is e?ected. If separator heater H, the products from this second heater 25
15 is operated at high pressure I remove_ the being passed into a separating system identical
separated liquids through valve 83 in line 84 to in function with separator i5, bubble tower 30,‘
stabilizer 85 which is operated‘at lower pressure etc. (with or without intermediate passage
or higher temperature to the end that light oils - through a soaking drum similar to drum ii);
30 free from desired gases are removed through oil
In this case the gas oil eliminated from the sec 30
take 86while' desired olefinic gases are removed ond bubble tower (except that portion thereof
through o?take 81.
‘which may be used as quenching oil or for re?ux
The gasesproduced in heater 63 and recov
or cooling purposes) is passed as previously de- I
ered from separator 15 and/or stabilizer 85 will
35 ordinarily have a content of gaseous ole?ns in‘
excess of 35% by volume, and if separator 15 .is
so operated as to eliminate substantial quanti
ties of methane and hydrogen through vent 823
the ole?n content of the total gases may be con
40 siderably higher, approaching as much as 70%
by volume. These ole?nic gases are passed
through line 88 ‘and compressor 89 and are ad!‘
mixed with charging stock to the process in line
It prior to heater Ii. Under the conditions pre
45 vailing in heater it these ole?nic gases are sub
stantially completely converted to desired prod
ucts of ‘the gasoline boiling range partly by direct
polymerization and partly by complex interac
tion with the gas oil undergoing cracking in heat
scribed to the low pressure-high temperature
heater 63. In this case the oleiinic gases in line
88 may be pumped by pump 89 to either of the two
high temperature-high pressure-heaters, or may
be divided in suitable proportion between both of
said heaters, in order to obtain the best balance of
operating conditions and results. , In this modi
iication of my process the overhead system fol
lowing bubble tower 30 and the analogous bubble
tower of the .second stage is ordinarily combined,
i. e. vapors from both bubble towers pass through
a common condensing, separating and stabilizing
system and the gasoline and gas-from both stages
are thereby collected as single streams. In fact
I may make use of one bubble tower suitably di
vided at its midpoint, the ‘cracked products from
er II. I may also pass a part of the stabilizer - each stage being introduced respectively above
gas from stabilizer 51 through line 59, valve 61,
line ‘68 and valve 90 to join other gasesdn line M
and below the middle dividing point, the tower ,
for treatment in heater ii.
from both sections are collected in a common
being so arranged that, gasoline vapors and gas
Heater ii ‘is operated in the temperature and‘ stream while the gas oil or unconverted material
55 pressure ranges previously set forth, the rate at
which oil is charged and the rate of heat input
being such that at least 35% of the gas oil intro
duced is converted to lighter products 'of the gaso
line boiling range. I prefer, however, to operate
er such conditions that at least 45% of the
gas oil is so converted. Due. to the further con-_
version of the ole?nic gases produced as previ
is collected in a separate stream from each sec
tion, these v,sepiau'ate streams being processed as
previously described.
For example, in the practice of this “dual once
of my pr
Iunay ‘use
apparatus as diagratically illustrated in t
2 wherein all elements numbered from 11 to 90
are identical with corresponding elements simi
ously‘described and to their interaction with the
oil charging stock, the ?nal yields of gasoline by
my process will be from 65% to 80%,the gasoline
being of high quality, in particular with respect
to its antiknock quality. In addition, I achieve
considerable economies in operating cost since
once-through” modi?cation of my process is as
follows: I close valve 98in line 6! and open
the excessive amount of recycling per unit of fresh
93 to the high pressure-high
feed charged (which is customarily employed in
larly numbered oi
. i.
Referring to Fig. 2, the operation of the “dual
valve $2 in line as whereby the intermediate oil
‘M ‘ ted in bubble tower 3@ it ~‘ "I through line
perature heater
M which operates within the sametrenge of tem
present commercial processes) is ‘eliminated thus ' perature
reducing the necessary size of my equipment and
eliminating excessive pumping costs.
In certain cases, depending largely on the
quality and cracking characteristics of the avail
pressure conditions previously de
scribed for high pressure heater ii and wherein
the subjected to relatively high conversion
but ordinarily to a lower conversion than that
carried out upon the fresh oil in'hi'gh pressure 75
. heater II. Following heater 9| the conversion
products pass through line 95 and valve 96'to
evaporator tower 91 which is operated under the
same temperature and pressure conditions previ
ously described for evaporator IS, the pressure on
the conversion products beingv appropriately re
duced at valve 96. By closing valve 95 and open
ing valve 98 the conversion products may be
passed through reaction chamber 99 which is sim ‘
.10 ilar in construction and.- operation to previously
2. A hydrocarbon conversion process compris
ing subjecting relatively high-boiling hfdrocar
bon oil to cracking at elevated temperatures and
pressures to convert a substantial portion there
of ' into hydrocarbons oi the gasoline boiling
range, separating the cracked products into tar
and vapors, fractionating said vapors to recover
a condensate oil heavier than gasoline and said
hydrocarbons oi’ the gasoline boiling range, sub
jecting said condensate oil in a second cracking 10
step at elevated temperatures and pressures to
convert a substantial proportion thereof to hy
drocarbons of the gasoline boiling range, sep
arating the cracked products into tar and vapors,
described reaction chamber I2, and in this case
the- pressure is reduced at valve I00 prior to the
products entering evaporator tower 91. From
i evaporator 91 heavy residual products are with
15 drawn from the system through valved line IIII
- Iractionating said vapors torecover a second con
_ while vapors pass overhead through line I02 and
valve I09 prior to entering bubble tower I04,
which is operated similarly to bubble tower, 30
previously described.~ Vapors from bubbletower'
20 I04 pass through line- I05 and join vapors pro
densate oil and said last-mentioned hydrocarbons
of the gasoline boiling range, subjecting said
second condensate oil in a separate zone to crack
ing at higher temperatures and relatively low
pressures to convert said second condensate oil 20
duced in the first cracking step at the vapor exit primarily to normally gaseous hydrocarbons of
relatively high ole?nic content and heavy tarry
from previously described bubble tower 30. In
like material, and returning ole?nic gases thus
termediate oils from bubble tower I04 are with
drawn from the bottom through line I06 and are produced to the initial cracking step for conver
25 sent by pump III‘I through line I09 and valve I09 ,sion into normally liquid hydrocarbons in the
presence of said oil.
to the entrance of low pressure heater 63 previ
3. A process in accordance with claim 1 where
ously described wherein these oils are converted
to ole?nic gases. These ole?nic gases so produced ’ in normally gaseous hydrocarbons are separated
after separation, etc., as previously described, may
from the hydrocarbons lot the gasoline boiling
diverted through valve III in line “2 whereby
gaseous hydrocarbons are admixed with said con
range resulting from said ?rst-mentioned crack
30 pass through valve III! in line 80 to heater II as
previously described or may wholly or in part be ‘ ing operation and at least a part of said normally
said ole?nic gases are passed to the inlet of
the second stage high pressure oil heater 94.
The foregoing being a full and complete de
scription of my invention, I claim:
densate oil undergoing conversion primarily to
normally gaseous hydrocarbons of relatively high
ole?nic content and heavy tarry-like material.
1. A‘ hydrocarbon conversion process compris
ing‘subjecting relatively high-boiling hydrocar
bon oil to cracking at elevated temperatures and
40 pressures to convert a substantial portion there
of into hydrocarbons of the gasoline boiling
range, separating the cracked products into tar
4. A process in accordance with claim 1 where
in hydrogen and methane are separated from
the hydrocarbons of relatively high ole?nic con
tent prior to the return thereof to the initial
cracking step.
5. A process in accordance with claim 1 where
in the relatively high-boiling hydrocarbon oil is
and vapors, fractionating said vapors to recover a distillate oil containing substantially no as
a condensate oil heavier than gasoline ‘and said ' phaltic constituents and substantially no previ- .
ously cracked constituents and is converted into
jecting said condensate oil in a separate zone to ' at least 35% of hydrocarbons of the'gasoline boil
cracking at higher temperatures and relatively ing range in passing once through the conver
sion zone.
low pressures to convert said condensate oil pri
6. A process in accordance with claim 1 where
marily to normally gaseous hydrocarbons of rela
tively high ole?nic content and heavy tarry-like ‘ g in said condensate oil is subjected to a cracking 50
temperature of about l000°-1700° F. while under
material, and returning ole?nic gases thus pro
> duced to the initial cracking step for conversion a pressure 01' about 0-200 lbs. per square inch.
hydrocarbons of the gasoline boiling range, sub
into normally liquid hydrocarbons in the presence
of said oil.
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