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Патент USA US2406312

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2,406,312
Patented Aug. 27.‘ 1946
UNITED STATES, PATENT OFFICE’.
OILS
Joseph Mason Barron, Port Arthur, Tex., assignor ‘
to The Texas Company, New York, N. Y., a cor
poration of Delaware
Application November 2 s, 1942, Serial No. 467,176‘
4 Claims.
1
.
This invention relates to certain improvements
in the cracking and coking of hydrocarbon oils.
The invention is concerned with the coking of
residual constituents from a pressure cracking
(01. 196—49) ‘
'
2
_ livering it to the coking zone wherein the pres
sure is lowered and the ‘residue ?ashed to coke.v
In the prior art practice coking has been ac
complished with the aid of considerable 'quan—
tities of hot vapors and gases and one of the
principal dif?culties encountered‘ has been that
ing and coking process in which a condensate
occasioned by the priming of the coking drum.
stock is subjected to a cracking temperature in a
In this priming, -‘ potential coke-forming con-p
heating zone and the heated eiiluenttherefrom
stituents are carried with the'ef?uentvapors from
subjected to counter-current contact with a
heavy or residualstock in a reaction chamber 10 the coking drum and create coking dif?culties
in vapor line and in the dephlegmating or frac
wherein separation of vapors from liquid residue
tionating portion of the system. In order to avoid
occurs and in'which the residue is ?ashed to
this di?iculty it has been necessary in the past
coke by means of its contained heat..
to operate with relatively low charging rates to
By having the heated condensate stock and
the heavy or residual oil in counter-current con 15 the coking drum and to maintain relativelyhigh
outage gauges therein, the outage gauge being
tact in the reaction chamber a su?iciently high
the
height of the" space in the drum'above the
temperature may be maintained therein that the
coke level. In accordance with the present in- '
residue may be ?ashed to coke solely by its con
operation and contemplates a combination crack- '
tained heat. Moreover, the re?uxing to which
the vapors are subjected while undergoing crack
vention, since the material directed to-the coking
20 chamber is essentially a liquid, the quantity of
vapors and gases evolved from the coking cham
ing in the countercurrent cracking chamber func
ber is greatly reduced with a consequent mate
tions to prevent the delivery to the subsequent
rial diminution in priming tendencies. The prac
fractionator of certain heavy potential carbon
tics of the invention thus makes possible the '
forming polymers with the result that the re?ux
condensate producedv in the ‘subsequent frac 25 maintenance of high charging rates to the coking‘
drum and high levels therein while avoiding
tionator is suitable as charging stock to a re
cycling cracking zone. It is' not necessary to
subject the overhead vapors from the reaction
chamber to any dephlegmating operation ahead
of the fractionating zone in which the cycle con
' priming, with the result‘ that a maximum amount
densate is formed. The overhead vapors from
the reaction chamber may be subjected to frac
densate which is cycledto‘the heating coil where
in it is subjected to cracking temperature and
tionation to separate from the gasoline or naph
tha distillate a higher boiling re?ux condensate
having a su?iciently low 90% 'A. S. T. M. distilla
tion point and carbon residue that it may be
subjected in a heating coil to high cracking tem
peratures and high rates of cracking per pass
of coke is produced per coke drum cycle.
In practicing the invention the vapors‘ from
the counter-current reactionv chamber are sub
jected to fractionation to obtain a re?ux con
the heated effluent is discharged into‘ the lower
portion of the reaction. ‘chamber. The separated
residue is withdrawn at temperatures adequate
to support autogenous coking and is delivered into
a lower pressure zone wherein it is coked by
without encountering coking difficulties therein
means of its contained heat.
The vapors from
the coking operation are subjected to a separate
so as to effect conversion into high anti-knock 40 primary dephlegrnation to form a heavy tarry
gasoline constituents.
condensate which is of highly aromatic character?
In accordance with the invention the con
well adapted for fuel oil. This heavy condensate
densate stock is passed through a heating coil
is either withdrawn as the product of the process
and delivered to the lower portion of a reaction
or is combined with‘ the hot residue withdrawn‘
chamber into the upper portion of which a heavy
from the reaction chamber for coking; ' The de
oil or residual stock is introduced for cracking
phlegmated vapors are subjected to dephlegma
in counter-current contact with the rising vapors
tion with a charging stock such as topped or re
therein. Separation of vapors from liquid residue
duced crude and the resultant mixture of re?ux
occurs in the reaction chamber and the vapors
condensate and unvaporized ‘charging stock is
50
and residue are separately withdrawn. The re
directed to an upper portion of the reaction
action chamber is maintained at a high cracking
temperature su?icient that upon the ?ashing of
the residue a conversion to coke will occur. Liq
chamber for cracking in counter-current contact
with the upwardly rising vapors therein.
For the purpose of more fully ‘explaining the
uid is prevented from accumulating in the reac
tion chamber by rapidly withdrawing it andv de 55 invention reference is had to the ‘accompanying
- 72,406,312
,
drawing which is a diagrammatic drawing of an
apparatus adapted for the practice of the inven- "
tion.
.47.
3
the temperature and so as to' obtain a condensate '
consisting of extremely high boiling constituents
'
collected as a tarry condensate in the bottom of
In. the apparatus illustrated the heating coil
the dephlegmator.
I0 is disposed in a furnace ll adapted to heat
the oil to a cracking temperature. The heated
e?iuent p'asses'through a transfer line I2 to a
reaction chamber l3 which is vertically disposed‘
The tarry condensate is
withdrawn through a line 32 and a portion there
of is continuously circulated by a pump33 and 7
line 34 back to the dephlegmating zone 29 so as >
to establish and maintain a continuousv flow of
liquid ‘through the dephlegmating zone over
line extends within the lower portion of the re-’ 10 ba?les or vapor-liquid contact elements therein
and heat-insulated. As illustrated, the transfer’
I action chamber and terminates in an enlarged -
so as to thereby prevent coking. The function
‘of this circulation is not to accomplish any cool- ‘
pipe’ or section [4 through which the heated
products are discharged in an upward direction‘
ing but merely to provide a‘?ow of liquid through
against a ba?le l5. In practice with a three-inch ‘
the dephlegmating zone which will prevent cok
transfer line the element [4 maybe composed of; 15
ing.
‘
'
I
~'
'
V
a six-inch pipe. The products passing from the.
' The dephlegrnated vapors pass upwardly from
coil H) to'the'reaction chamber l3 will consist‘;
the primary dephlegmating zone 29 to secondary,
dephlegmating zonev 39 into which charging stock,
‘ largely of vapors'and gases and upon being dis- ‘
charged through the enlarged pipe I'd against?
such as crude petroleum or topped or reduced
the ba?le l5 an efficient diffusion of‘ the vapors 20 crude,,is‘introduced by a pump 35 through a line
' and gases is accomplished. rA' black oil'ior‘resid-i
36. 'I‘heresultant mixture of re?ux condensate
ual stock‘ isintroducedto an upper ‘portion ‘of
and unvaporized charging ‘stock is withdrawn
the reaction chamber 13 ,througha line 16 which
from the tray 3| through‘a line 37 and is directed
extends within the reaction‘ chamber and 'termi-.
by' a pump 38 and line 39 thence through line Is
I nates in a distributororspray' nozzle ll. " The 25 to the upper portion of the reaction chamber
spray ll'is arranged to spray the liquid'oil-in- a
I3. If desired this mixture of condensate and
downward direction through 'the chamber ‘50 as
unvaporized charging stock may be directed
to bring the liquid oil into intimate contact with‘v
through ‘a branch line 4%? and heating coil 4!
the rising vapors. It is desirable
V
to have ‘ an un~
which may be conveniently disposed in the, fur“
obstructed space between the distributor l5 and 30 nace H. -In the coil4l ‘the oil, is subjectedto a
spray'nozzle llffree from ba?‘les" or any other
cracking temperature and the heated ef?uent is
contact elements, since it is contemplated to
maintain such elevated ‘temperatures therein
that injurious coking would take place if sur
faces were presented upon'which cokev deposition
could occur.
'
‘
'
'
"passed througha transfer line 42*to‘the line l6
for introduction'to the reaction chamber 13.
Primary dephlegmate obtained from the coke
35 still vapors may be withdrawn as'a fuel oil prod
uct of the process.- This product is of a‘ high
aromatic character and due to its solvent prop
‘
‘Separation of ‘vapors from liquid residue‘ takes‘
place in‘ the reaction chamber E3. The separated;
erties is particularly-well adapted for blending
vapors pass'thr-ough a vapor line It to’ a frac
purposes in the preparation of fuel oils._ '' Instead V
tionating. tower I 9. This tower is provided with
of being utilized as ‘fuel oil the primary dephlega
suitable vapor-liquid contact elements suchas
bubble trays and with suitable cooling andfre
mate may be directed by a pump £53 and line 44
to the'coking drum 26 onto the transfer line
?uxing means’. ' The vapors are fractionatedin
24 so as to' combine it with'the mixture of vapors
‘ the tower l9 to separate the desired naphtha or
and-liquid which is passed from the reaction
gasoline fractions from higher boiling re?ux con;
145
dens'ate. This re?ux condensate is recycled by a
1
1
1
' ;
‘
5
r . c
I
r
.7
'
pump 20 through a line 2| to the heating coil ' '
vapors from the fractionating section 313 and
passed .to-a' condenser 45 thence to a ‘receiving
Liquid is prevented from accumulating in the
reaction chamber ‘I3 bythe rapid withdrawal of
liquid residue therefrom. In practice a} very
'
_
Naphtha or gasoline fractions are removedas ,
the
H1. tower
The 'gasoline
l9 as a or
vapor
naphtha
to a condenser'22
fractions passthence
from
to a distillate‘ receiver or gas separator 23; ‘ Y
3
Y I
chamber~l3 to the coking drum,
drum or gas separator 46.
50
‘
'
In practicing the invention the cycle condensate '
is subjected 'to cracking temperature such as
1000° R4030? Fain the heating coil l0 and dis
charged into the reaction chamber l‘ 3 wherein the
slight amount of vapor may be withdrawhwith ‘ cracked products are ‘contacted with the down
,theliquid, an amount merely suf?cient to’insure 55 flowing residual stock. Superatmospheric pres
that no liquid level is maintained in the reaction ‘
sures,’ such as 200-600 p. s. i.; with cracking
chamber. The'residue is withdrawn through a
temperatures upwards 01° 900°. F. are maintained
line 24 and pressure-reducing valve 275 to a ‘cok
in the reaction chamber. 'vLiquid is prevented
ing drum 26 wherein it is converted to coke by
from accumulating in the reaction chamber I3
means of its contained heat. In practice a plu
so that the coking of the residual constituents
rality of coking drums are employed so that while .
may be postponed until they reach the coking
one is' 'on stream the other or others may be
drum 25. Itis not necessary to applyany heat
down for cokeremoval or cleaning and thus con
to the coking drum other than that of the‘ enter—
tinuity in the complete process maintained.
ing oil. By’ withdrawing the liquid residue from
1 The coking drums are suitably heat-insulated.
1 a The vapors from the coking drum pass through
a Vapor line 21 to a primary ‘dephlegmating' zone.
1 As illustrated, a tower 28 is provided having a
the reaction chamber at temperatures upwards
of 920° F‘. and delivering it to the lowerpressure
coking chamber autogenous conversion to produce
a marketable coke is readily accomplished. Tem
5 lower section 29 and an upper section 30 sepa- 1 _ peratures of 920° F.-'925° F. are recommended for
‘
1
Q
5
rated bya trap'out tray 3|. ‘I'he vapor line 2?
communicates with the lower section 29 wherein
the vapors'from the coking operation are sub
jected to a‘separate primary dephlegmation; A ‘
limited amount of cooling is supplied to the de
. phlegmating zone 29 so as not to unduly‘ reduce
the residue passing from the reaction chamber
through the transfer line 24. The coking is con- i
ducted under reduced pressures approximating
atmospheric pressure, preferably not over about
.50 p. s.*i. and at temperatures of about 850°’ F.‘ 7
Separated vapors from thelvreactiongchamb‘er
5
2,406,312
t
6
,
ing liquid and upwardly‘v rising vapors to counter
I3 pass through the vapor line I'B'at a tempera
ture of 900° F.—91'0° F. and. the vapors are frac
current'contact in. an unobstructed zone within
tionated in the tower IBYun'der approximately the
the reaction chamber at cracking temperatures
of upwards of 900° F. under 200-600 pounds
same pressure as obtains‘ in the reaction chamber
or, if desired, under a somewhat lower superat
pressure, withdrawing the separated vapors from > ’
sure of 400 lbs. in the reaction chamber the frac~
an upper portion of the reaction chamber at a
temperature of the order of 900° F., withdrawing ‘
tionation may be conductedat approximately that
the liquid residue from the lower portion thereof
mospheric pressure. For example, with a rpres~
at a temperature of the order of 920° F. at a
pressure or the pressure may be reduced to an in~
termediate pressure such as 200-300 lbs. The
fractionation is conducted so as to take overhead
a distillate fraction of desired end‘ point, such
as a 400° F. end point fraction, and obtain a re~
rate adequate to prevent the accumulation of
liquid residue therein, delivering the withdrawn
residue to a coking zone wherein the pressure
is reduced to a low pressure not exceeding about
50 pounds and wherein a temperature approxi
?ux condensate comprising the higher boiling
constituents which is cycled to the cracking coil 15 mating 850° F. is maintained by means of the
hot residue introduced to thereby effect coking
Hi.
solely by the contained heat of the residueLsub
jecting said vapors withdrawn from the reaction
chamber to fractionation to separate lighter
complished, for example,‘ by cooling _ a small
amount of the re?ux condensate from tower l9 20 products from higher boiling re?ux condensate,
cycling said re?ux condensate to the aforesaid
and re?uxing it in the dephlegmator 29/ It is
heating coil, subjecting evolved vapors ‘from the
desired to condense in this primary dephlegmator
coking zone to dephlegmation with a residual
only the extremely high boiling contsituents so
In the dephlegmator 29 only a relatively small
amount of cooling is supplied which can be ac
charging stock to form a resultant mixture of
re?ux condensate and unvaporized residual
that the bulk of the vapors will remain uncon
densed and pass to the secondary fractionating
section 30. Temperatures of about 800° F.-8l0° F.
changing stock, passing said mixture of re?ux
condensate and unvaporized residual charging
stock through a heating coil wherein it is heated
are maintained at the bottom of the dephlegmat»
irlg zone 29 without coking due to the hot circu
lation accomplished by the pump 33. Due to the
relatively small amount of re?ux supplied to the
dephlegmator 29 and to the circulation of the hot
oil by the pump 33 there is a minimum tempera
ture differential through the dephlegmator so that
the uncondensed vapors pass to the dephlegmat
ing section 30 at temperatures approaching 800°
F. The residual charging stock introduced by the
pump 35 is preferably passed in heat exchange
with the hot products of the system prior to in
troduction to the dephlegmator 3E} and the mix
ture of re?ux condensate and unvaporized ‘charg
ing stock is withdrawn from the tray 3! at tem
peratures of about ‘750° F.-780° F. This mixture
is either passed directly to the reaction chamber
I3 through line H5 or is passed through the heat
ing coil 4!: wherein it is heated to temperatures of
the order of 800° F.-900° F. before being intro
duced into the reaction chamber.
In the prior practice when using, for example,
coke drums 40 ft. by 10 ft. in size it was necessary
to maintain the coke drum outage gauge at about
23-24 ft., that is coke depths of 16-17 feet, in order
to prevent priming and consequent coking in the
primary dephlegmator. By means of the pres
ent invention the outage gauge may be reduced to
to a temperature of the order of BOO-900° F. and
30 directing the heated mixture to the upper portion ’
of the aforesaid reaction chamber as the residual
I stock introduced therein.
2. In the combination cracking and coking of
hydrocarbon oils the process that comprises pass
35 ing a condensate stock through a' heating coil
wherein it ‘is subjected to a high cracking tem
perature, delivering the heated stream into the
lower portion of a vertically disposed reaction
chamber wherein separation of vapors from liquid
residue takes place, introducing a stream of
heated residual stock into an upper portion of
the reaction chamber, subjecting resultant down
flowing liquid and upwardly rising vapors to
countercurrent contact in an unobstructed zone
45 within the reaction chamber at cracking temper
atures of upwards of 900° F. under 200-600
pounds pressure, withdrawing the separated
vapors from an upper portion of the reaction
chamber at a temperature of the order of 900°
50 F., withdrawing the liquid residue from the lower
portion thereof at a temperature of the order
of 920° F. at a rate adequate to prevent the ac
cumulation of liquid residue therein, delivering,
the withdrawn residue to a coking zone wherein
as low as 15-1’? feet, that is the coke depths in 55 the pressure is reduced to a low pressure not
exceeding about 50 lbs, and wherein coking is
creased to 23-25 feet, with a consequent increase
effected solely by the contained heat of the resi
in fresh charge capacity of some 30-50%.
due, subjecting said vapors withdrawn from the
While I have described a particular embodiment
‘reaction chamber to fractionation to separate
of my invention for purposes of illustration, it
should be understood that various modi?cations 60 lighter products from higher boiling re?ux eon
densate, cycling said re?ux condensate to the
and adaptations thereof, which will be obvious to
aforesaid heating coil, subjecting evolved vapors
one skilled in the art, may be made within the
from the coking zone to dephlegmation with a
spirit of the invention as set forth in the ap
pended claims.
I claim:
' residual chargingstock to form a resultant mix
65
I. In the combination cracking and, coking of
hydrocarbon oils the process that comprises pass
ing a condensate stock through a heating coil
wherein it is subjected to a high cracking temper
ature, delivering the heated stream into the lower 70
portion of a Vertically disposed reaction chamber
wherein separation of vapors from liquid residue
takes place, introducing a stream of heated
residual stock into an upper portion of the re
ture of reflux condensate and unvaporized resi
dual charging stock, passing said ‘mixture of
reflux condensate and unvaporized residual
charging stock through a heating coil
it is heated to a temperature of the
800-900“ F. and directing the heated
to the upper portion of the aforesaid
wherein
order of
mixture
reaction
chamber as the residual stock introduced therein.
3. In the combination cracking'and coking of
hydrocarbon oils the process that comprises pass
action chamber, subjecting resultant down-?ow 75 ing a condensate stock through a heating coil
2,406,312
7
8
wherein it is subjected to a high cracking tem-'
'perature, delivering the heated stream into the
hydrocarbon oils the process that comprises pass
ing condensate stock through a heating coil‘
wherein it is subjected to a, high cracking tem
lower portion of a vertically disposed reaction
chamber wherein separation of vapors from liquid
‘ peratureAdelivering‘the heated stream into the
residue takes place, introducing a stream ,of I
lower portion of a vertically disposed reaction
heated high boiling constituents, formed ‘as
chamber wherein separation of vapors from
hereinafter speci?ed, into an upper portion ‘of
liquid residue takes place, introducing a stream
of heated high boiling constituents, formed as
1 the reaction chamber, subjecting resultant down
' ?owing liquid and upwardly, rising vapors .to
hereinafter speci?ed, into an upper portion of the’
reaction chamber, subjecting resultant down
?owing liquid and upwardly rising vapors to
counter-current contact in an unobstructed zone
within the reactionchamber at cracking temper
atures of upwards of 900° F. under 200-600
pounds pressure, withdrawing separated vapors
countercurrent contact in an unobstructed zone
within the reaction chamber at cracking tem
from an upper portion of the reaction chamber
peratures of upwards of 900°.F. under 200-600
at a temperature of the order of 900° F., vwith 15 lbs. pressure, withdrawing the separated vapors
drawing liquid residue from the lower portion
from the upper portion of the reaction chamber
thereof at a temperature of the order of 920°‘F.
I at a temperature of the order of 900° F., with
at ,a‘rate adequate to prevent the accumulation
of liquid residue therein, delivering the with
drawn'residue to a coking zone wherein the pres
sure is reduced and wherein coking is e?ected
drawing the liquid residue from the lower portion
thereof at a temperature of upwards of 920° F.
20 and at a rate adequate to prevent the accumu
lation of liquid residueg'therein, delivering the ,
solely by the contained heat of the residue, sub
withdrawn residue ‘toa coking zone wherein the '
pressure is reduced and wherein coking is ef
fected solely by the contained heat of the residue,
' jecting said vapors withdrawn from the reaction
chamber to fractionation to ‘separate lighter
products from higher boiling re?ux condensate,
25 subjecting said vapors withdrawn from the re
cycling said re?ux condensate to the aforesaid
action chamber to fractionation to separate
heating coil, subjecting the evolvedyvapors from
lighter products from higher boiling re?ux con- _
the coking zone to a separate dephlegmation in -
a primary-dephlegmating zone to’ form a heavy
densate, cycling said re?ux condensate to the
aforesaid heating coil, subjecting evolved- vapors
tarry condensate, subjecting resultant dephleg-_
30 from the coking zone to dephlegmation withv a
mated Vapors to dephlegmation with a residual
residual charging stock to form a resultant mix
charging stock to form a resultant mixture ;of
ture of re?ux condensate and unvaporized resi
reflux condensate and unvaporized residual
dual charging stock, passing said mixture of
charging stock; passing said mixture of re?ux
re?ux condensate and unvaporized V residual
condensate and unvaporized residual charging 35 charging stock through a heating coil wherein
stock through a heating coil wherein-it is heated
it is heated to a temperature of the order of
to temperatures of the order of 800-900° F. and
BOO-900° F. and directing the resultant heated
directingthe resultant heated products to ‘the’
products to the upper portion of‘ the reaction
, upper portion of the reaction chamber to con- ;
chamber to constitute the aforesaid high boiling
'stitute the aforesaid high boiling constituents 40 constituents introduced thereinto.
v introduced thereinto.
’
4. ‘In the combination cracking and coking ‘of
'7
’
JOSEPHJMASON BARRON. f
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