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Патент USA US2406313

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Aug. 27,1946.
‘Filed Nov. 28, 1942
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Patented Aug. 27, 1946
Joseph 'Mason Barron, Port Arthur, Tex.,.assig11or' ‘
to The Texas Company,
proration of Delaware New York, N. Y., ‘a cor
'Application'November 28, 1942, Serial No. 467,177
‘:2 ‘Claims.
(0]. 196-49)
This invention relates to certain "improvements
in the cracking and coking of hydrocarbon oils.
The invention is concerned with the coking of
coking chamber ‘is greatly reduced Witha con
sequent material diminution in priming tend
residual constituents from a pressure cracking
operation and contemplates a combination
cracking and coking process in which a conden
The practice of the invention thus
makes possible the maintenance of high charg
ing rates to the coking drum and high levels
therein While avoiding priming, with the result
sate stock is subjected to acracking temperature
in a heating zone and the heated e?luent there
that a maximum amount of coke is produced per
coke drum cycle.
from subjected to ‘countercurrent contact with a
Additional advantages of the high ‘temperature
heavy or residual stock "in a reaction chamber 10
wherein separation of vapors from liquid residue
in the reaction chamber made possible by the
countercurrent operation therein are ‘the result
occurs and in which'theresidue is ?ashed to coke
bymeans of its contained heat. v
ant ‘higher‘conversion per pass on the material
The invention is based ‘upon ‘the discovery that
delivered to the reaction’chamber and the im~
by having the heated condensate stock and the 15 provement in the e?iciency of the operation by
reason of the fact that the reaction chamber va
pors pass directly to the dephlegmating or frac
tiona'ting portion of the system at maximum ‘tem
‘In accordance with the invention a condensate
stock is passed through a heating ‘zone and de~
livered to the lower portion of arreaction cham
ber into the upper ‘portion :of'which a, heavy oil or
highly aromatic character well adapted for fuel
oil ‘blending. This ‘heavy condensate may be
residual stock is introduced ‘
' --
Withdrawn ‘as a fuel
oil product of'the process.
However, ‘due to the heat ‘made available by the
countercurrent contact in the reaction chamber
it is advantageous to combine the heavy tarry
condensate with the cracked'residue being de
livered to the coking drum. The primary de
phlegmation of the coke still vapors is carried on
at "relatively high temperatures within the crack
reaction chamber is'maintained at ajhigh crack
ing temperature su?icient that ‘upon ‘the v?ashing
of the residue a conversion to coke ‘will occur.
ing temperature range‘and coking‘ tendencies'may
‘be reduced to a negligible quantity Withinv the
dephlegmator by maintaining therein a constant
circulation of the-condensate formed._ This oil‘;
sure is lowered and the residue ?ashed to coke.
In'the prior art vpractice coking has ‘been ac
complished with the aid of considerable quanti
cu-lation together with the return of the primary
condensate to the coking drum insures that this
encountered vhas _ been
that 40 heavy material will tbe looked in the coke drum
occasioned ‘by the priming of the coking drum.
and not in the dephlegmator, or that the ‘con
densate may be withdrawn ‘as a liquid product in
cases wherein it is desired ‘to obtain such fuel
In this priming, potential coke-forming constit
uents ‘are carried with the e?luent vapor-s from
the coking drum ‘and create coking ‘difficulties in
the vapor line and in the dephlegmatin'g or. frac
tionatin'g portion of the system. In order vto 445
avoid this dii?culty it has been necessary in the
past to Operate with relatively low charging
‘The deph‘legmated coke still vapors from the
primary dephlegmating operation are combined
with the vapors separately Withdrawn ‘from the
reaction chamber and subjected to dephlegma
rates to the coking drum and to maintain rela
tion with charging stock such as topped or re
tivelyv high outage gauges therein, the outage
duced crude and the resultant mixture ‘of reflux
gauge being the height of the space in the drum "50 condensate and unvaporized ‘charging stock is di
In‘accordance with the
. rooted to the upper portion of 'the reaction cham
present invention, since ‘the material directed to
the coking ‘chamber is essentially ‘a liquid, ‘the
quantity of vapors and gases evolved from the
‘ further fractionation to separate a higher i-boil
above the coke level.
The uncondensed vaporsfare subjected to
ing re?ux ‘condensate ifrom flower boiling prod
!55 vmtsand..this re?ux condensateis cycled through
amount of cooling is supplied to the dephlegmat
ing zone 25 so as not to unduly reduce the tem
perature and so as to obtain a condensate con
a heating coil wherein it is subjected to a crack
7 ing temperature and the heated e?iuent is dis
charged into the lower portion of the reaction
sisting of extremely high boiling constituents col
chamber for countercurrent contact with the
For the
purpose of more fully explaining the
lected as a tarry condensate at the bottom of
the dephlegmator. A portion of this heavy con
densate is continuously withdrawnjthrough a line
28 and directed by a pump 29 through a line
now had to the accom
30 to the upperportion of the dephlegmating
panying ‘drawing which is a diagrammatic eleva
tion of an apparatus adapted for the practice of 10 zone 25. The function of this circulation is not
to accomplish any cooling but merely to establish
the invention.
In the apparatus illustrated a heating coil in ,_
is disposed in a furnace ll adapted to heat the, '
‘and maintain a ?ow of liquid through the de
' phlegmating zone
?uent passes through a transferline l2 to a re
action chamber l3 which'is vertically disposed
which will prevent coking.
. Heavy dephlegmateor condensate is withdrawn
oil to a cracking temperature. The heated ef-'
the'dephleg'mator 25 through a line 3| and
15"- from
system as a fuel oil product
discharged from the
and heat insulated. As illustrated, the transfer
of the ~re- '
line extends within the lower portion
an enlarged ‘
action chamber andttermin'ates in
:pipe or section l4 through which the heated
pump 32 through a line 33
to the coking drum 22 or to the transfer line 20,
so as to combine the heavy tarry material with
,or is directed by. a
the mixture of vapors and liquid which is passed
are discharged in an upward direction 20 from the reaction chamber 13/00 the coking
against a ba?le l5. In practice with a three- _
The dephlegmated ‘coke still vapors pass up-v ‘
inch transfer line the element In may be com
wardly from theprimary dephlegmating zone 25
posed of a six-inch pipe. The products passing
from the coil It to the reaction chamber will
to the dephlegmating zone 26 wherein‘ they ‘are’
consist largely of vapors and gases and. upon 25 combined with the vapors which are separately
withdrawn from the reaction chamber l3 and
being discharged through the enlarged. pipe [4
which are introduced through the vapor line [9
against the baf?e IS an e?icient diffusion of i the
anda pressure reducing valve 34. In the de
vapors and gases is accomplished.’ A black oil
phlegmating zone 26 the combined vapors are
or residual stock is'introduced to an upper por
tion of the reaction chamber l3 through a ‘line 30 dephlegmated with charging stock, such as crude
l6 which extends within vthe reaction’ chamber
petroleum or topped or reduced crude, introduced
by a pump 35 through line 36. The resultant
mixture of re?ux condensate and unvaporized
l1. The spray I1 is arranged to spray thelliquid
charging stock is withdrawn from the tray 21
oil in a downward'direction through the cham
35 through a line 31 and directed by a pump 38
.ber'so as to bring the liquid oil into intimate
through the line It“ to the reaction chamber. [3.
contact with the rising vapors. It is desirable to
from the rdephlegmate
Uncondensed vapors-pass
have an unobstructed space between the‘ dis
ing zone 26 through a vapor line 39 to a frac
tributor l5 and spray nozzle l1, free from ba?les
tionating tower 40. This tower is equipped with
or any other contact elements, since it is con
templated to maintain such elevated tempera 40 bubble trays or othersuitable vapor-liquid con
and terminates in a distributor or spray nozzle
tures therein that injurious coking would take
place if surfaces were presented upon whichcoke
deposition could take place- At the top of the
chamber a ring spray pipe l8 may be disposed
for spraying oil against, the wall of the chamber
so as to produce, a down?owing liquid ?lm which
' is conducive to the prevention of coke deposits
tact elements and is supplied with conventional
cooling or re?uxing means (not shown). The
vapors‘ are subjected to fractionation therein to
separate a lighter product of desired boiling point
from higher boiling re?ux condensate. There-P
flux condensate is withdrawn through a’ line 4| :
and directed by apump 42 and line '43 to the
heating coil Ill. The overhead vapors pass to a
residue;‘ takes
condenser 44 thence to a distillate receiver or
Separation of vapors from liquid
The separated 50 gas separator 45 wherein the desired gasoline '
place in the reaction‘chamber l3.upper
portion of
Q on the wall of the chamber.» I
or naphtha distillate is collected.
vapors are withdrawn from the
A convenient method of supplying- the limited
the chamber through a vapor line l9. Liquid
amount of cooling required inv the dephlegmat
is prevented from accumulating in the chamber
ing zone 25 is to withdraw a smallportionof
by the rapid withdrawal "of liquid residue there
from. In practicea very slight amount of vapor .55 the re?ux condensate from line 4| through a
branch line 46 thence through a cooler 41, and
*may be withdrawn with the liquid, an amount
sufficient to insure. that no liquid level is
direct the cooled condensate by a pump 48 and
line 49 to the dephlegmating section 25 or con
maintained in the reaction chamber. The’ resi
a line 20 and pressure
veniently to the line 30. The line 43 may be
' due is withdrawn through
reducing valve 2i to a coking drum 22 wherein
provided with a branch-line 56 by which a rel—.
atively small portion of the hot condensate may
it is converted to coke by means of itscontained
be directed to the ring spray 18 for supplying
heat.~ In practice a plurality of coking drums
the down?owing ?lm to the reation chamber
are employed so that while one is on stream the
iii. If desired, this hot condensate spray may
other or others may be down for coke removal
be eliminated and ,only- the black oil, conducted
and cleaning and‘thus continuity in the com
plete process is maintained. The coking drums
through line l3,_admitted to the upper portion
of the reaction chamber, in which case the black
are suitably heat insulated.
V t
‘ '
The vapors from the coking drum pass through
oil is preferably introduced at the top of- the
a primary dephlegmating zone.
chamber and sprayed in such a way that a por
' a vapor line 23 to
tower 24 is provided having a
As illustrated, a
lower section 25 and an upper section 26 sep
tray 21. The vapor line 23
' arated by a trapout
tion thereof will be directed against’the wall
of the chamber to produce a down?owing ?lm;
Inpracticing the invention typicalloperating
conditions involve temperatures of ,1015°jF.-,-1030.°
the vapors from the coking operation are ,sub the outlet of theiheating coil, l9, tempera+
.jected to a separate dephlegmation. 1 A limited 75
communicates with
the lower section 25 wherein ‘
tures of 920° F.-925° F. in the bottom of the
I claim:
reaction chamber I 3 under a pressure of 350
p. s. i., coke drum temperatures of 850° F.—855° F.
under a pressure of 160 pounds, temperatures of
900° F.-910° F. in vapor line H), temperatures of
920° F.-925° F. in the e?iuent passing from the
reaction chamber to the transfer line 20, a pres—
sure of 150 pounds in ‘the tower 24 with tempera
tures of 790° F.-810° F. at the bottom of de
phlegmating zone 25 and temperatures of 800°
F.-810° F. in the trapout tray 21 and with a pres l0
sure of 135 pounds in the tower 40 with tempera
tures of 680° F.—700° F. at the bottom of the
It is not necessary to
coking drum other than that of the entering oil. 15
the reaction chamber at tempera
tures upwards of about 920° F. and delivering it
ing streams, maintaining
a' temperature approxi
to the coking chamber autogenous conversion to 20 mating 920-925°
produce a marketable coke is readily accom
The improved results made
vention are shown by a comparison' with the
ing and consequent coking the primary dephleg so'
mator. The present invention has made it pos
sible to reduce the outage gauge to 20 feet, that
as low as 15-17 feet, that is with coke depths of
23-25 feet, with a consequent increase in fresh
charge capacity of 30 %-50%.
While the practice of the invention does not (0
preclude the passage of the
upper portion of the reaction chamber.
.2. The process according to claim 1 wherein
the said heavy tarry condensate is combinedwith
liquid residue being delivered to the coking zone
for coking.
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