close

Вход

Забыли?

вход по аккаунту

?

Патент USA US2109875

код для вставки
March E, w3..
H. v. ATWELL
PROCESS FOR THE ’I‘REÁ'I‘MENT- OF' HYDROCARBON OIL
Filed Deo. 31, 1955
2,109,75
Patented Mar. 1, 1938
2,109,875
UNITED STATES PATENT OFFÍCE
2,109,875 `
PROCESS FOR THE TREATMENT OF HYDRO
CARBON OIL
Harold v`. Arwen, white Plains, N. Y., assignm- to
Gasoline Products Company, Inc., Newark, N. J.,
a corporation of Delaware
Application December 31, 1935, Serial No. 56,898
6 Claims. (Cl. 1236-49)
This invention relates to processes for the vapors are removed and fractionated to create
cracking of hydrocarbon oils and pertains more ' additional redux condensate, preferably in two
particularly to a process for producing gasoline fractions, a -light fraction and a heavy fraction,
or other light hydrocarbons from relatively heavy the latter being passed to a separate stage for
Cîl oils which cannot ordinarily be economically and
conversion, and the former, lighter fraction being
satisfactorily subjected to conventional coil cracked in a separate cracking coil at high tem
cracking.
perature and utilized to heat the heavy stock
It is an object of my invention to provide a introduced into the second soaking chamber.
plural~coil cracking process wherein a plurality
Another feature of my invention contemplates
of clean distillate cracking stocks are subjected the separate cracking of a clean stock such as
10
to conversion in separate cracking coils and a
Virgin gas oil and the introduction of the
heavy stock, such as reduced crude, heavy dis
cracked products into the first-mentioned evap
tillate, or the like, is simultaneously subjected to orator, and where two stages are utilized, the sep
a cracking operation in a reaction zone by aid
arate cracking of the heavy reflux condensate
of heat derived from one of the clean cracked from the initial fractionating operation, and the
stocks.
v
introduction of the resulting cracked products
More specifically, it is an object of my inven
into the second evaporator.
tion to provide a plural-stage cracking process
`'I'he above-mentioned and further objects and
wherein heavy oil, such as reduced crude, heavy advantages of myiinvention and the manner of
20 distillate, or the- like, is introduced into a crack~
attaining them will .be more fully explained in 20
ing chamber or reaction zone and maintained
cient to cause a considerable amount of conver
the following description taken in conjunction
with the accompanying drawing.
The single ligure of the drawing represents dia
sion thereof, the resulting cracked products are
grammatically in side elevation and partly in
therein at cracking temperature for a time sufñ
25 introduced into an evaporator, residuum is re
moved from the evaporator, and likewise a side
stream of heavy condensate, while the vapors arepassed overhead to a fractionating zone wherein
a ñnal desired distillate is removed as an over
30 head product and two condensate fractions are
formed, one being a more or less conventional
gas oil reflux condensate and the other a rela
tively lighter intermediate condensate.
The
former reflux condensate is passed to a separate
section an apparatus adapted to carry out the 25
process of my invention.
Referring more particularly to the drawing,
fresh heavy charging stock, such as reduced
crude, heavy distillate, fuel oil, or the like, is
forced by pump I through conduit 2 into soaker 30
`or reaction chamber 3, reaching there either di
rectly through valved by-pass line 4 or heating
-coil 5, located in furnace 6. In the soaker the
heavy oil is maintained at a cracking tempera
cracking stage for additional conversion, while
ture and subjected to conversion, as will be eX
the latter reflux condensate, of a lighterv char
acter, is passed through a separate cracking coil
drawn from the evaporator may be subjected to
plained more fully hereinafter, and the resulting
cracked products are conducted through transfer
line 'I having control valve 8 into the base of
evaporator 9, wherein separation thereof into
vapors and liquid residue takes place. The 40
vapors pass upwardly through the tower around
baffle trays or other fractionating elements Ill,
thence through vapor line II into the base of
fractionating column I2. In this column the
vapors are subjected to fractional condensation 45
in the usual way, the resulting reflux condensate
additional conversion in a separate stage.
being collected in two fractions, a heavier frac
A still further object of my invention is to pro
vide a plural-stage cracking process wherein two
cracking stages operating in the manner set forth
drum or reaction zone for additional conversion
tion, which is withdrawn from the base of the
tower through draw-off line I3, and a lighter
fraction, which is collected on trap-out tray I4, 50
and withdrawn therefrom through pipe I5. This
last-mentioned, lighter reflux condensate is
forced by pump I 6 through heating coil Il of
furnace 6 and is therein raised to a relatively
55 and thence to a second evaporator, from which
high cracking temperature of, for example, 1000 55.
and subjected to a high cracking temperature,
after which the cracked products are mixed with
40 the reduced crude, heavy condensate, or other
heavy charging stock for passage to the soaking
chamber, the highly heated cracked light reñux
condensate constituting the source of heat for
cracking the heavy charging stock. Simul
taneously, if. desired, the heavy condensate with
in the preceding paragraph are utilized, the
heavy cracked condensate from the first-men
tioned evaporator passing to a second soaking
35
2
2,109,875
During the operation a heavy reñux condensate
to 1100c F., under a relatively high pressure of,
for example, 500 to 1000 pounds per square inch, is collected on trap-out tray 3l and is conducted
through draw-off pipe 32, having pump 33,
and is sub-jected to conversion. The resulting
cracked products are conducted through transfer - through valved by-pass line 34, or alternatively
through heating coil 35 into soaker 36 and is
5 line i6 having control valve I9 into the soaker 3
therein subjected to additional cracking in a
in mixture with the heavy charging stock intro
manner similar to that desired in conjunction
duced thereinto through line 2, the relative quan
tities and temperatures of the heavy oil and with soaker 3. A light reflux condensate is re
lighter cracked reflux condensate being such that moved from fractionating tower 31 and forced
through pipe 38 by pump 39 into heating coil 40, 10
a temperature suñicient to promote active crack
ing of the heavy oils is attained in the soaker,
tiis temperature being, for example, in the range
of 850 to 900° F. When the coil 5 is used to pre
heat the heavy charging stock, the amount of
heat necessary to be supplied by way of heating
coil I1 is naturally less than when the heavy
charging stock is passed directly through line 4
to the soaker 3. Whether or not heating coil 5
is used the temperature to which the oil is raised
therein will depend upon the character of the
heavy oil to be cracked. When reduced crude
is used, this oil may readily be raised to a
cracking temperature and, if desired, be sub
jected to a considerable amount of conversion
in the coil 5. But when exceedingly heavy or
dirty stocks are used it will, in most instances,
be desirable to utilize less drastic conditions in
the coil 5, so that the oil is heated with rela
tively little or no cracking, or to avoid the use
of the coil 5 at all, this being done by closing
control valves 20 and 2l and opening valve 22.
Because of the relative temperature to which
the heavy oil and the lighter reiiux condensate
are subjected, the coil 5 is most suitably located
in the convection portion of the furnace, and
the coil i1 in both the convection and radiant
portions of the furnace, as shown on the draw
ing. The heavy charging stock and lighter
cracked reflux condensate are shown as entering
40 the soaker 3 through a common connecting pipe,
but obviously separate connecting lines might
be used for this purpose, if desired.
Simultaneously with the introduction of. heavy
charging stock through line 2, a relatively clean
charging stock, such as gas oil, is introduced to
the system through conduit 23, being forced by
pump 24 through heating coil 25 located in
furnace 26. In this heating coil the oil is raised
to a desired cracking temperature, for example,
in the range of 900 to 1000° F. and is therein
subjected to conversion, the resulting hot cracked
products being passed through transfer line 21,
having control valve 28, into the base of evapo
rator 9. Alternatively part or all of this highly
heated stock may be conducted through pipe 29
having control valve 30 into the soaker 3 for
further conversion therein in mixture with the
heavy charging stock and lighter reflux conden
sate, and in this event, the oil is introduced
60 through line 29 would constitute a source of heat
for the cracking of the heavy charging stock.
The pressure utilized in the heating coil 25 must
necessarily _be high enough to force the oil into
soaker 3 when that path of. travel is chosen, but
ordinarily it may be said that the pressure in the
heating coil 25 may range from a few atmos
pheres to several hundred pounds per square
inch, most desirably being in the neighborhood of
200 pounds per square inch. The pressure
70 utilized in the evaporator 9 may be controlled
relative to the pressure existing in the several
cracking coils by proper manipulation of the con
trol valves in an obvious manner. A vapor phase
soaking drum (not shown) may be used in con
junction with heating coil 25 if desired.
wherein it is raised to a relatively high cracking
temperature and subjected to conversion, the
resulting cracked products being introduced into
the soaker 36 by way of transfer line 4l having
control valve 42. Reference numeral 43 indi 15
cates the trap-out tray from which the lighter
reflux condensate is withdrawn, and 44 indicates
the furnace structure housing the heating coils
35 and 40. The heating coil 35 may be placed
in or out of. operation, as desired, by manipu 20
lation of valves 45, 46, and 41. Whether» or not
the heating coil 35 would be used would depend
upon the character of the heavy condensate
withdrawn from trap-out tray 3| for introduc
tion into the soaker 36. If this condensate is of 25
such character that it can be cracked to a cer
tain extent or even heated, without deleterious
deposition of carbon, it may be passed through
the heating coil 35 and therein subjected to
sufficient heat to raise its temperature without 30
causing injurious deposits of carbon in the coil.
But if this stock is of a dirty or coke-forming
character the use of the coil 35 may best be
avoided.
From the soaker 36 the cracked and digested 35
products are conducted through conduit 48, hav
ing control valve 49, into the base of evaporator
50, and are therein separated into vapors and
liquid residue. The vapors pass upwardly
through the tower around baiiie trays or other
contacting devices 5I, then pass through vapor
line 52 into the base of the fractionator 31,
wherein they are subjected to reflux condensa
tion in the usual way. A heavier reflux con
densate is collected at the base of the tower and
is withdrawn therefrom through draw-01T line
53 for passage to a following cracking stage or
A lighter reflux
for use in any desired manner.
condensate is collected on the trap-out tray 43,
as already described. Fractionated vapors of
the desired end point are removed from the top
of fractionating tower 31 to vapor pipe 54 and
condenser 55, the resulting condensate being col
lected in receiver 56, this being, for example,
gasoline distillate. In a` like manner, fraction
ated vapors are removed from the top of frac
tionating column l2 through vapor pipe 51 and
condenser 58, the resulting condensate being col
lected in receiver 59, this also being, for ex
ample, gasoline distillate.
v60
The heavier reiiux condensate from the base
of fractionator l2 is subjected to treatment in a
manner similar to that of the .gas oil intro
duced to the system through pipe 23. That is,
the reilux condensate withdrawn from the base 65
of fractionator I2 is conducted through pipe I3
under pressure generated by pump 60, thence
through heating coil 6| located in furnace 62,
wherein it is raised to a relatively high cracking
temperature of, for example, 900 to 1000° F.
under a, pressure of from a few atmospheres to
several hundred pounds per square inch, and
subjected to conversion. A vapor phase soaking
drum (not shown) may be used with heating
coil 6l, if desired.
75
2,109,875
The resulting cracked products are conducted
through transfer line M, having control valve 63,
into the base of evaporator 50, or alternatively
through conduit 65 having control valve t6, into
the soaker 30 in mixture with the heavy oil from
,pipe 32. When so introduced into the soaker,
this highly heated condensate will supply part of
the heat necessary to carry out the cracking of
the heavy oil introduced into the soaker. Refer
10 ence numeral 6l! indicates a trap-out tray from
which a `heavy condensate may be withdrawn
via line 68 for passage to another cracking Zone
or for any desired use. Residue collecting in the
base of evaporator 50 may be withdrawn from
15 the process by way of draw-off line 69.
Liquid residue collecting in the base of evapo
rator 9 is withdrawn through conduit 'l0 and may
be diverted directly from the process, or alter
natively part or all of this liquid residue may be
20 conducted through by-pass line 'H into conduit 32
for further conversion in the soaker 36, the ñow
of the residue being controlled by valves ‘I2 and
73. When liquid residue from the base of evapo
rator 9 is passed to the soaker 36 it will, in most
25 instances, be found preferable not to utilize the
heating coil 35, since this liquid residue has very
marked coke-forming tendencies. In case the
heavy condensate is clean enough for coil crack
ing or heating and the residue too dirty for that
30 purpose, the condensate may be passed through
the heating coil 35 and the residue directly to the
soaking drum 3E, by suitable pipe connections.
An alternative operation would be to introduce
the heavy condensate and/or residue into the
35 heating coil ¿i0 near the outlet for cracking and
digestion thereof.
In conducting an operation according to my
process, the charging oils introduced through
pipes 2 and 23 may be reduced crude and gas
40 oil derived from a common source of crude oil,
for example, the gas oil being a conventional
clean gas oil cracking stock, and the reduced
crude being such as is usually charged to a
viscosity-breaking operation, or even a heavier
45 reduced crude. In the soaker 3 the temperature
may suitably be about 880° F. and the pressure
about 200 pounds per square inch, although the
temperature» may suitably range 50 degrees more
or less higher or lower than the value men
50 tioned. The pressure likewise is -not critical but
may vary considerably, for example, in the range
of several atmospheres to 1000 pounds per square
inch. The gas oil passing through the heating
coil 25 is desirably raised to a cracking tempera
55 ture of about 925 to 950° F., although higher or
lower temperatures in the range of 900 to 1000”
F. approximately are suitable. The pressure in
this heating coil is preferably such that so-called
vapor phase cracking may be carried out, e. g.
60 about 200 pounds per square inch, although
higher pressures ranging from 500 to 1000 pounds
per square inch may be used if desired. Where
pressures in excess of 200 pounds per square inch
are utilized on the oils undergoing cracking, the
65 pressure in the evaporator may be with benefit
somewhat lower, this pressure suitably being
about 200 pounds per square inch, for example.
In the heating coil l'i the lighter reflux con
densate from fractionator I2 is preferably sub
j-ected to a more drastic cracking operation than
that taking place in the heating coil 25, an ex
ample of desirable conditions in the coil Il being
a temperature in the range of 1000 to 1100° F.,
e. g. about 1050° F., and a pressure of from 500
to 1000 pounds per square inch, e. g. about 600
3
pounds per square inch. Similar conditions may
prevail in corresponding heating Zones 6i and
40, as well as soaker 36. The heavy. distillate
removed from trap-out tray 3l should be consid
erably heavier than that normally subjected to _
coil cracking as a clean stock and may have, for
example, a boiling range extending upward from
about 650° F. while the reflux condensate removed
from the base of fractionator I2 is a clean gas oil
condensate of the type ordinarily considered 10
proper cracking stock for a conventional vapor
phase cracking operation, or may be slightly
lower in boiling point, falling, for example, in the
range of 550 to 700° F., or thereabouts. The
lighter reflux condensate removed from trap-out
tray iii of tower l2 is a still lower boiling frac
tion, falling, for example, in the range of 400 to
600° F., although this cut may be similar to that
ordinarily subjected to a reforming operation,
then including the heavier ends of gasoline which 120
it is desired to reform. For convenience- in the
claims the several condensate cuts from the
evaporator and the base of the fractionating
column and intermediate point in the fractionat
ing column may be referred to, respectively, as
heavy condensate, intermediate condensate, and
light condensate. Two cracking stages have been
illustrated, but if desired, the reflux condensate
removed through pipe 53 and the heavy con
densate removed through pipe 68, as well as the v30
residue removed through conduit BQ, may be sub
jected to additional cracking in further cracking
stages similarly operated.
While I have described a particular embodi
ment of my invention for purposes of illustration,
it should be understood that various modifications
and adaptations thereof may be made by one
skilled in the art within the spirit of the inven
tion as set forth in the appended claims.
I claim:
140
1. The process of treating hydrocarbon oil
which comprises introducing heavy oil charging
stock not suitable for use as clean cracking stock
into a soaking zone wherein it is maintained at a`
cracking temperature, introducing the resulting ,4,5
soaked products intov a ñrst separating zone
wherein vapors separate from liquid residue, frac
tionating resulting vapors to form a heavy, an
intermediate, and a light reflux condensate, pass
ing said light reñux condensate through a heat
ing zone in a stream of restricted cross-sectional
area to raise it to a high cracking temperature
and introducing the resulting highly heated products into said soaking Zone to maintain the de
sired cracking temperature therein, removing
said intermediate condensate, passing it through
a second heating Zone in a stream of restricted
cross-sectional area to raise it to a high cracking
temperature, introducing the resulting cracked
products into a second separating zone, fraction 60
ating the resulting vapors to form an intermedi
ate condensate and a light condensate, passing
said light condensate last-mentioned through a
third heating zone in a stream of .restricted cross
sectional area, introducing the resulting products
at cracking temperature into a second soaking
zone, and introducing said heavy reiiux V con
densate into said second soaking zone in such
quantities that the resulting mixture in the soak
ingzone does not fall below an active cracking
temperature and fractionating the products from
the second soaking _zone to-form a desired dis
tillate.
2. The process of treating hydrocarbon oils
which comprises introducing relatively heavy 175
4
2,109,875
charging oil into a soaking zone wherein it is
~ raised to a cracking temperature and subjected to
conversion, introducing the resulting cracked
products into a first separating zone,fractionating
the separated vapors to forman intermediate con
densate and a light condensate, passing said light
condensate through a heating zone in a stream
of restricted cross-sectional area and therein
raising it to a cracking temperature, introducing
10 the resulting highly heated oil into said soaking
zone in quantities suñcient to maintain a desired
cracking temperature therein, withdrawing said
intermediate condensate and passing it through a
second heating zone in a stream of restricted
15 cross-sectional area and therein raising it to a
cracking temperature and subjecting it to con
version, introducing the resulting cracked prod
ucts into a second separating zone, fractionating
the separated vapors to form an additional
20 quantity of reflux condensate, passing reflux con
densate so obtained through a third zone in a
stream of restricted cross-sectional area and
therein raising it to a cracking temperature, in
troducing the resulting highly heated products
:25 into a second soaking Zone in mixture with liquid
residue withdrawn from the first separating zone,
subjecting the mixture to conversion in said soak
ing zone, passing the resulting cracked products
from the second soaking zone into the second
30 separating zone, and condensing light fraction
ated vapors from the fractionating operation to
form a desired light distillate.
3. The process of treating hydrocarbon oil
which comprises passing a clean distillate crack
ing stock through a heating zone in a stream of
restricted cross-sectional area wherein it is raised
to a cracking temperature and subjected to con
version, introducing the r-esulting cracked prod
ucts into a vapor separating zone, subjecting re
sulting vapors to fractionation to form a heavy
reflux condensate, an intermediate condensate
and a light reflux condensate, passing said light
condensate through a separate heating zone in a
stream of restricted cross-sectional area, wherein
45 it is raised to a relatively high cracking tem
mixture at a cracking temperature for a suf
ficient time to cause cracking thereof prior to
its introduction into said second separating Zone.
4. The process of treating hydrocarbon oil
which comprises passing a clean distillate crack
ing stock through a heating zone in a stream of
restricted cross-sectional are-a wherein it is
raised to a cracking temperature and subjected
to conversion, introducing the resulting cracked
products into a vapor separating Zone, separating
a heavy fraction from the oil introduced there
into, subjecting resulting vapors to fractionation
to form an intermediate and a light reflux con
densate, passing said light condensate through a
sepa-rate heating zone in a stream of restricted
cross-sectional area, wherein it is raised to a rela
tively high cracking temperature and subjected
to conversion, mixing with the resulting highly
heated cracked products heavy oil not suitable
for use as clean cracking stock, in quantities in
suñicient to reduc-e the temperature of the mix
ture below a cracking value, maintaining the
mixture at a cracking temperature for a suf
ñcient time to cause cracking of the added heavy
oil and introducing the resulting cracked prod
ucts into said vapor separating zone, conducting
aforesaid heavy fraction to a separate cracking
zone wherein it is raised to a cracking tempera
ture and subjected to conversion by admixture
therewith of the highly heated cracked conden 30
sate, introducing the resulting cracked products
into a second separating zone, -iractionating re
sulting vapors to form an intermediate condensate
and a light condensate, diverting said intermedi
ate condensate from the cracking operation, pass 35
ing said light condensate through a third crack
ing Zone and raising it therein to a relatively high
cracking temperature, introducing the resulting
highly heated products into said separate crack
ing Zone to maintain the desired cracking tem
perature therein, and passing said intermediate
condensate derived from the initial íractionating
operation through a fourth heating zone in a
stream of restricted cross-sectional area wherein
it is raised to a cracking temperature and sub» 45
jected to conversion and introducing the result
perature and subjected to conversion, mixing with
the resulting highly heated cracked products
ing cracked products into said second separating
heavy oil not suitable for use as clean cracking
zone.
stock, in quantities insufiicient to reduce the tem
perature of the mixture below a cracking value,
maintaining the mixture at a cracking tempera
ture for a sufficient time to cause cracking of
the added heavy oil and introducing the result
ing cracked products into said vapor separating
65 zone, passing the intermediate condensate re
moved from the Íractionating zone through a
third cracking zone in a stream of restricted
cross-sectional area wherein it is raised to a
cracking temperature and subjected to conver
60 sion, introducing the resulting cracked products
into a second separating zone and subjecting the
vapors so obtained to fractionation to form an
intermediate condensate and a light condensate,
diverting said intermediate condensate from the
65 process, and passing said light condensate
through a fourth cracking Zone in a stream of
restricted cross-sectional area and therein sub
jecting it to conversion under relatively high
temperature, introducing resulting cracked prod
70 ucts into said second separating zone, mixing
aforesaid heavy reflux condensate with said
cracked products prior to their introduction into
said second separating zone in such quantities
that the resulting mixture does not drop below
a cracking temperature, and maintaining the
5, In the cracking of hydrocarbon oils, the
process that comprises introducing charging 50
stock into a heating zone and heating said stock
therein to a cracking temperature to effect crack
ing, separating resultant cracked products into
vapors and residue in a separating Zone, fraction
ating the separated vapors in a fractionating 55
zone to form a heavy condensate and a lighter
condensate, directing the lighter condensate to a
separate heating zone and heating it in a flowing
stream therein to a cracking temperature, heat
ing a cycle condensate to a cracking temperature 60
in a separate heating zone, combining said heavy
condensate and said heated cycle condensate
with said lighter condensate, after the latter has
been raised to a cracking temperature, to thereby
raise the heavy condensate to a cracking tem 65
perature and subject it to cracking and advanc
ing the resultant commingled products to a sec
ond separating Zone wherein separation of vapors
from residue takes place, and fractionating the
separated vapors in a second iractionating zone 70
to form a light distillate and a condensate con
stituting said cycle condensate.
6. In the cracking of hydrocarbon oils, the
process that comprises introducing a gas oil
charging stock into a heating zone and heating 75
5
2,109,875
said gas oil therein to a cracking temperature to
effect cracking, ‘separating resultant cracked
products into vapors and residue in a separating
zone, fractionating the separated vapors in a
fractionating Zone to form a heavy condensate,
an intermediate condensate and a lighter con
densate, directing the intermediate condensate to
a separate heating zone and heating it in a iioW
ing stream therein to a cracking temperature,
combining said heavy condensate with said in
termediate condensate, after the latter has been
raised to a cracking temperature, to thereby
raise the heavy condensate to a. cracking tem
perature and subject it to cracking and advanc
ing the resultant commingled products to a sec
ond separating zone wherein separation of vapors
from residue takes place and fractionating the
separated vapors, directing said lighter conden
sate to a separate heating zone and heating it in 5
a flowing stream therein to a cracking tempera~
ture, introducing a residuum charging stock into
the stream of lighter condensate, after the latter
has been raised to a cracking temperature, to
thereby raise the residuurn stock to a cracking 10
temperature and subject it to cracking and subi
je-cting the resultant commingled products to
fractionation to form a desired distillate.
HAROLD V. A'I'WELL. -
Документ
Категория
Без категории
Просмотров
0
Размер файла
850 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа