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Патент USA US2120655

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Junè 14, 1938.
LE ROY G. STORY
2,120,655 ,
CONVERSION OF HYDROCARBON OILS
Filed April 21, 1951
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.Patented June 14, l‘i938
2,120,t55
UNITED STATES PATENT OFFHCE
2,12 0,655
CONVERSION 0F HYDROCARBON OILS
Le Roy G. Story, Mount Vernon, N. Y., assigner
to The Texas Company, New York, N. Y., a cor
poration of Delaware
Application April 21, 1931, Serial No. 531,693
7 Claims.
-This invention relates to the conversion of
hydrocarbon oils and has to do particularly with
la combination of liquid phase and vapor phase
cracking which provides certain advantages and
presents features of novelty that will be more
fully described and claimed hereinafter.
An important object of the present-invention
is to produce from a fresh charging stock, es
sentially, a residue of coke, a distillate of gaso
10 line having a high antiknock value and fixed
gases which may be used as fuel or for other
purposes as desired.
The invention contemplates the stripping of
fresh charging stock by contact with the vapors
155 from a coking operation, the separation of a clean
cracking stock for a pressure cracking system,
the separation of selected cuts for vapor phase
cracking and the coking of the residue liquids
from the stripping and pressure cracking opera
20 tion by the sensible heat of the vapor phase
cracked products. With suitable type of appara
tus and novel methods of operation the volatile
products may be concentrated at one zone in
the system whereby a gasoline of high anti
25 knock value, consisting of both liquid phase and
vapor phase cracked products, may be separated,
the heavier components fractionated to produce
selected cuts which may be subjected separately
to a pressure cracking system and a vapor phase
30
cracking system, while the unvaporized residual
oil from the system may be reduced to coke in
coking stills.
The process of the invention is flexible so
that` a wide selection of cutsv for cracking may
be made by segregating various fractions accord
ing to the desired volatility or refractorinessand
each fraction subjected to the most suitable type
of conversion operation. .Accordingly, the low
boiling products vaporized in the pressure crack
,10 ing operation may be separately dephlegmated
to produce selected cuts for vapor phase and
liquid phase cracking; the residual liquid or pres
sure tar may be flash distilled under reduced
pressure to likewise produce selected cuts for the
45 same purpose, if desired; or, the entire vapor
fraction from both the pressure stills and the
flash still may be concentrated in one large tower,
which also receives vapors from the crude strip
per, and the resulting mixture of vapors frac
tionated to separate the desired gasoline, and to
produce at the same time a fraction suitable for
vapor phase «cracking stock and a clean con
densate adapted for pressure still cracking.
The invention may be more clearly understood
55 by referring to the accompanying drawing where
'(Cl. IBG-Jill)
in an apparatus is shown for conveniently carry
ing out the invention and forming one embodi
ment thereof.
f’
.
In the drawing the reference character l rep
resents a heater for heating oil under pressure; 5
2 and 3 a pair of stills for separating vapors
from residual oil; ¿l a dephlegmator for dephleg
mating or'fractionating vapors from the stills 2,
3; 5 a vapor phase cracker for cracking oil in the
Vapor phase; ß and 'i a flash still and dephleg
mator for vaporizing residue and fractlonating
the vapors from the stills, 2, 3; 8 and 8a, coke
stills for reducing residual oil to coke by the
heat of the cracked products from the Vapor
phase cracker 5; and 9 a combined stripper and
fractionating tower for stripping crude- and for
fractionating any> or all the vapors from thestills
2, 3, flash still 6, vapor phase cracker 5, and coke
stills 8 and 8a.
The heater I comprises any well known type
oi furnace having a coil or tubular heater l0,
located therein, and connected to an extraneous
supply line ll and a clean distillate charge line
l2. A burner i3 supplies heat to raise the oil
passing through the coil Il) to conversion tem- _,_
peratures. A transfer line Hl, conducts oil from
the heater to either or both of the stills 2 and_3
by means of the branches l5 and I6 respectively.
The stills 2 and 3 are shown as vertical cham
bers having a vapor connecting line 2l] and a
liquid overñow pipe 2l. The vertical type of still
is shown for illustrative purposes only and other
shape and designs of stills may be employed,
if desired, with equal success. The stills are pref
erably insulated to retain the heat content of the
oil and provide reaction time at conversion tem
peratures. Each still is provided with residue
draw-off lines 2,3 and 24 for withdrawing residual
liquid continuously or intermittently. A vapor
pipe.25, regulated by a valve 26, conducts Vvapors
from the stills 2 and l3 to a line 2l, referred to
hereinafter. A branch line 28, in which is inter
posed a valve 29, serves to conduct the vapors, if
desired, to the dephlegmator 4.
'I‘he dephlegmator 4 may conveniently take
the form of a bubble tower equipped with trays
to contact the vapors and reflux condensate. A.
cooling coil 30 is provided in the top of the de
phlegmator to supply cooling thereto by an eX
traneous cooling medium. A vapor pipe 3l con
ducts vapors from the dephlegmator to a con
denser coil 32. A condensate line 33 serves to
convey the condensate from the condenser to a
receiver 34 which is equipped with the usual gas
_release line 35 and liquid draw-off pipe 36.
2
2,120,655
The dephlegmator is further provided with
lines 36’ and 31, regulated by valves 33 and 39
respectively, communicating with the bottom
thereof to withdraw reiiux condensate from the
bottom of the tower. A line 40, in which is
6I and 84 whereby the residuum from the flash
still 6 may be contacted with the products from
the vapor phase cracker.
A clean distillate or reflux condensate line 85,
connected to line 43, serves to withdraw conden~
interposed a valve 4l, connected to the side of
the dephlegmator, serves to withdraw a side cut
sate collecting in the bottom of the fractionator E3
or condensate in line 21 to storage or to conduct
therefrom, if desired.
the lcondensates to the charge line 84 whence they
The reflux condensate
pipes 36 and 81, as well as the side pipe 4D, sepa
rately connect to a line 21, referred to hereto
fore, which communicates at diiferent elevations
with the upper fractionating section of the tower
9 by means of branch lines ï42 and ‘43. A line
45, regulated by valve 45, communicating with
15 the line 21, leads to the tubes or‘coil 41 located
in the vapor phase cracking furnace 5.
The vapor phase cracker 5, shown for purposes
of illustration as a diagrammatical section, may
be any well known or preferred type of Ivapor
are forced by pump 9| to the coil i8. A conden
sate line 93, connected to the side of the fraction li)
ator and having a pump 93', serves to conduct, if
desired, a side cut from the fractionator to the line
45Íleading to the vapor phase cracker 5. A vapor
line .95 conducts vapors from the top of the frac
tionator .to the condenser coil 96. A condensate
ïline TS1-connects the condenser coil 98 to a re
ceiver 95 which is equipped with the usual gas
releaseline 99 and liquid draw-oli? line |88.
In -practicing the invention with an apparatus
phase cracking apparatus. A convenient type of such as that shown lin the drawings, charging 20
stock, such as crude oil,~is-charged tothe stripper
furnace for such use maybe similar to that dis
closed in U. S. Patent No. 1,717,334, June 11, through line 62 wherein the fresh charge comes
1929, to Luiz de Florez. A pipe 48, controlled by in Contact with the hot vapors therein and the
valves 49 and >5t, connects the cracking vcoil 41 charge may be partially cracked and the lighter
tothe stripper section of `the tower 8. Branch constituents vaporized. The vapors, including
lines 5| and 52 connect .the line 48 to the coke the volatilized constituents of the fresh charge,
stills '8 and 8a.. A vapor line 53 serves to conduct pass throughV the riser 8l to the fractionator. A
clean distillate collects above the partition 8D
vapors from the coking stills 8 and 8a to the bot
and is conducted vby the lines 88 and 54 to the
tom of the stripper section of tower 9.
`
-Referring now Vto the flash still 6, a »residue pressure crackingv coil 10. The clean distillate 30
30
line `55 serves to `conduct residuum thereto from passing to the coil I0 is preferably >a cracking
stock of the nature of gas oil. If desired, an ex
the stills 2 and 3. A vapor ‘line 55 conducts va
pors from the iiash drumïö to the dephlegmator 1. traneous >charge of o'il may be introduced through
A vapor line 58 connects "the dephlegmator 1 toV the'line ~Il. The addition of extraneous oil is
sometimes desirable in order to provide a uniform
to Ul the line 21 referred to heretofore. A residue
draw-off line 68 serves to'wìthdraw residue from charging rate in case the supply from the frac
tionator runs low and more particularly is such
the flash still 6. A-branch line 8l serves to con
duct the residue, if desired, to a charge line 62 a supply of charge from ïline H convenient in
starting up operations.
A
,
leading to the stripper section of tower 9. A re
The oil in the heating coil i8 is raised to con
40 iiux condensate line ‘63 conducts reflux conden
sate from the bottom of dephlegmator 1 >to the version temperatures of the order of '150° F.
clean distillate charge line 84. A branch line 65, 950" 'FL and a pressure of 200-600 pounds per
controlled by valves 66 and 61, connects the re~ square inch may be carried on the coil and stills
2 and -'3. Two stills are shown in the drawings
flux line V153 with the line "21, wherebyv the con
densate may be transferred to the fractionator but any number may be used. Likewise, the stills 215
are' shown connected with vapor lines and liquid
9. A branch line 68, controlled by valve 159, con
nects the line 55 to the line-21 ahead of valves overflow lines, but it is contemplated that a low
18 and 1| in line 21 so that the condensate,` if liquid level may be maintained in the stills in
desired, may be sent to the vapor phase cracker which case there would be no overflow but instead
via lines 21 and 45. A condensate line 15 serves the >hot oillmay be charged to one or both stills 50
andthe entire contents of the stills maintained
to withdraw condensate from the middle of de
phlegmator 1 to the line v65.
substantially Vas vapors. The vapors from the
Referring to the stripper and >fractionator 9, it stills Zand 3 pass through-the line 25 and may
will be noted that vthe upper section of the `tower be passed directly to the fractionator 9 through
' constitutes a fractionating »tower while the lower
section constitutes the stripper. The sections are
separated by a partition 88 having a Vapor riser
8i therein so that vapors from the stripper may
pass to the fractionator. While the stripper and
60 fractionator are shown as a single tower with the
fractionator superimposed on the stripper, never->
theless the two sections may be made as separate
units and the invention contemplates such an
arrangement.
Y
v A charge line 62 leads to the top of `the stripper
to conduct fresh charge thereto aswell as re
siduum from the line 6I, if desired. A residue
draw-,olf line 83 serves to withdraw unvaporized
oil from the bottom of the stripper. A branch line
70 B4, having a pump 84'` serves to transfer the re
siduum from line 83,7if desired, to the line 48 `to
be mixed with the cracked products from the va
por phase cracker 5 and thence to be conducted
to the coke stills or to _the stripper. A branch
line 85, controlled by valve 86, connects the lines
line
21.
"
..
In one method of operation'the vapors from
stills 2 and 3 may be passedthrough rline v28 to the
dephlegmator 4. In the dephlegmator the vapors
are fractionated to separate a gasoline fraction
which Yiscondensed in condenser 32 while the
heavier constituents are collected as reflux con
dens'ate. The reiiux condensate may be collected
entirely in the bottom of the tower .4 or separated
into selected cuts and o_ne Ycut taken off as a side
stream throughV line 4'0. In case a side stream
is taken off it is preferable to charge this cut to
the vapor phase cracker through line 45 while
the heavier cut in the bottom of the tower 4 is
passed through line 36 and line 21 to the frac
tionatorrg or directly to line 80 to be backtrapped
to the heater coil I8.
When no side cut is taken
from the tower >4 then the reflux may be passed
entirely, or in part through lines 31 and 45 to
either the vapor phase cracker 5 or the tower 9.
The residue from stills 2 and 3 may be con- u
2,120,655
ducted continuously or intermittently to the flash
still 6. A reduced superatmospheric pressure is
maintained in the still 6 so that the lighter frac
tions of the residual oil are immediately flashed
by their sensible heat into vapors. The vapors
pass to dephlegmator 1 while residue is with
drawn through line 60 to be disposed of as de
scribed hereinafter. The vapors in dephlegmator
1 may be separated into one or more cuts, asV de
sired. In some cases it may be desirable to pass a
substantial amount of the vapors to vapor phase
cracker 5 and this may be done by suitable regu
lation of valves 10 and 1I in line 21, or the vapors
by other regulation of the same valves may be
sent directly to the fractionator 9. Likewise, one
or two cuts of condensate may be made in theV
tower 1, these cuts being drawn off through lines
63 and 15. In this way a side cut may be taken
off through line 15 and sent to the vapor phase
cracker by suitable regulation of valve 69 in
branch line 68 and valve 61 in line 66, while a
heavier condensate from the bottom of tower 'I
may be returned to coil I0 through line 94. In
some cases it may be desirable to make a single
cut of condensate in tower 1 and this cut may be
withdrawn through line 63 and passed to the coil
I0 or conducted through line 65 to either the
vapor phase cracking coil or to the fractionator
9 by suitable regulation of valves 69 and 61 in
30 lines 68 and E6 respectively.
Y
While I have described the manner in which
particular fractions from either the dephlegma
tor 4 or dephlegmator 1 may be passed to the
vapor phase cracker 5 or the fractionator 9, it is
to be understood that selected fractions of liquids
and/or vapors from both dephlegmators may be
passed simultaneously to the Vapor cracker 5 or
fractionator 9. It will be observed therefore that
ñexibility of operation isV an essential feature of
‘my invention whereby selected outs may be
3
-entirely or in part, alone or in mixture with the
residuum from flash still 6, into the line 48 to be
treated as just described.
The vapors collecting in the .fractionator sec
tion of tower 9, which may comprise all or a` part
of the vapors from the entire system, depending
on whether the dephlegmator Il is by-passed, are
fractionated and the reflux condensate or clean
distillate, entirely or in part, passed to the heat
er coil I9. Sometimes it is desirable to separate
the reñux condensate into selected cuts, and
therefore, I have shown a line 93 for making a
side cut to be returned to the vapor phase cracker
5. The latter is particularly advantageous in case
the dephlegmator 4 is by-passed and all the va
pors concentrated in the fractionator section of
tower 9.
Obviously many modifications and variations
of the invention, as hereinbefore set forth, may
be made without departing from the spirit and 20
scope thereof, and therefore only such limitations
should be imposed as are indicated in the ap
pended claims.
I claim:
l. The method for conversion of hydrocarbon
oils which comprises passing fresh charging stock
into contact with vapors from a coking Zone to
form unvaporized liquid and vapors, fractionat
ing said vapors to form a vapor fraction and a re
flux condensate, subjecting said condensate to
conversion conditions of temperature and super
atmospheric pressure to separate low boiling
products as vapors from residual oil, flash distill
ing said residual oil to produce an unvaporiz/ed
residual liquid and a selected distillate for vapor I:
phase cracking, subjecting only said selected dis
tillate toa vapor phase cracking operation, mix
ing the unvaporized residual oil from the system
with the products from the vapor phase cracking
operation and passing the resulting mixture to 40
treated in a manner to provide optimum con
said coking zone.
ditions for both yield and quality of the desired
2. The method for the conversion of hydrocar
bon oils by a series of continuous steps which
comprises subjecting a hydrocarbon oil to con
version conditions of temperature and superat
mospheric pressure to produce a vapor fraction
and an unvaporized residue, fractionating said
ñnished products.
The oil in passing through vapor phase cracker`
5 is raised to a temperature suitable for conver
sion in the vapor phase, say between 950° F. and
1150° F. The hot products of conversion may be
transferred through line 48 directly to the strip
per section of the tower 9. It is preferable, how
.
vapor fraction in a first fractionating zone to
form a desired product, subjecting the unvapor
ized residue to flash distillation in a flashing Zone 50
under a reduced superatmospheric pressure,
fractionating the vapors evolved during ñash dis
ever, that these products go to the coke stills 8
and 8a by means of lines 5l and 52, in order that
the heat thereof may be used for coking the re
sidual oils from the system. Two coke stills are tillation in a second fractionating Zone to sepa
shown, for purposes of illustration, but only one ' rate a selected fraction suitable for vapor phase
is ordinarily used at a time while the other is cracking, subjecting said fraction, while still re
cleaned of the coke deposition therein. The va
taining heat from its previous treatment, to a
pors from the cokegstills pass through lines 53 to vapor phase cracking operation, conducting the
the stripper section Where they contact the heavy vapor phase cracked products to a coking Zone,
oil charged thereto through line 62.
separate fromA said flashing zone, passing the va
The residual oil from the system -is preferably pors from the coking Zone to a stripping zone, in
Gr)
commingled with the hot vapors from the vapor
troducing fresh charging stock into said stripping
phase cracking operation. Referring first to the zone, separate from said flashing Zone, separating
a clean condensate from the resulting vapors,
residuurn from the flash still, this oil may be
passed through lines 6l and 62 to the stripper. utilizing clean condensate so obtained, as said hy
„ It is preferable, however, to by-pass it through drocarbon oil undergoing conversion, and pass
lines 85 and 84 to be commingled with the vapor ing residual oil from the stripping Zone to said
phase cracked products. Therefore, this residue coking Zone.
3. The process of treating hydrocarbon oil
may be used to cool the cracked products in case
they are passed directly to the stripper through which comprises introducing crude oil into a
line 48 or the mixture of residuum and vapors
stripping zone, wherein heat is supplied by hot
may be passed through lines 5| and 52 to the vapors and the crude is partially vaporized, col
coke stills where the residue is reduced to coke lecting a clean, relatively heavy condensate, and
by the sensible heat- of the vapors. Likewise, the an intermediate condensate, and condensing the
unvaporized oil collecting in the bottom of the lightest of the crude vapors as a desired product,
stripper is withdrawn through line 83 and passed
introducing said relatively heavy condensate into
55
60
65
70
4
2,120,655
a cracking Zone wherein cracking conditions of '
temperature and pressure are maintained and said
condensate is subjected to conversion, separating
the products of conversion into vapors and a liquid
residue, extracting gasoline from said vapors, in
heated cracked vapors into said coking zone to
maintain the temperature thereof, and intro
ducing hot vapors from saidrcoking Zone into
said stripping Zone to aid in the stripping
thereof.
Y
reduced pressure wherein partial vaporization
5. A process in accordance with claim 3 where
in said relatively heavy condensate second men
thereof takes place, subjecting resulting vapors to
partial condensation to form a relatively heavy
tioned is recycled to said cracking Zone first
mentioned.
condensate and an intermediate condensate, leav
6. A process in accordance with claim 3 where
in unvaporized portions of said crude charging
troducing said residue into a iiashing zone of
ing relatively light vapors uncondensed, introduc
ing the residue from said ilash Zone into a coking
zone, cracking in the vapor phase the intermedi
oil are introduced into said coking zone.
' highly heated cracked vapors into said coking Zone
'7. The method for the conversion of hydro
carbon oils by a series of continuous steps, which
comprises subjectingY a hydrocarbon oil to con
to maintain the temperature thereof, and intro
version conditions of temperature and superat
ducing vapors from said coking Zone into said
mospheric pressure to produce a vapor fraction
and an unvaporized residue, fractionating said
vapor fraction, in a iirst fractionating Zone, sub
ate condensate last mentioned, introducing the
crude stripping Zone to aid in the stripping of said
crude oil.
4. The process of treating 'hydrocarbon oil
which comprises introducing crude oil into a
stripping zone wherein heat is supplied by hot
vapors, and the crude is partially vaporiz'ed, col
lecting a clean relatively heavy condensate and
condensingA the lightest of the crude vapors as
a desired product, introducing said condensate
into a cracking zone wherein cracking conditions
of temperature and pressure eXistand said con
densate is subject to conversion, separating the
products of conversion into vapors and a liquid
residue, extracting gasoline from said vapors, in
troducing said residue into a iiashing Zone of
reduced pressure wherein partial vaporization
thereof takes place, subjecting resulting vapors
to partial condensation to form a condensate,
leaving relatively light vapors uncondensed, in
roducing the residue from said iiashing zone into
a coking zone, cracking in the vapor phase the
condensate last mentioned, introducing the highly
jecting the unvaporized residue to flash distilla
tion in a Íiashing Zone under a reduced superat
mospheric pressure in a flashing Zone, separate
and apart fromthe coking zone hereinafter speci
ñed and from the resultant vapors produced in
the coking operation, fractionating the vapors
evolved during iiash distillation, in a second frac
tionating zone, to separate a selected fraction
suitable for vapor phase cracking, subjecting
said fraction, while still retaining heat from its
previous treatment, to a vapor phase cracking 30
operation, conducting the vapor phase cracked
products to a coking zone separate from said
iiashing zone, passing the vapors from the coking
zone to a stripping zone, introducing fresh charg
ing'stock into said stripping zone and passing 35
residual oil from the stripping zone to said coking
zone.
LE ROY G. STORY.
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