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Патент USA US2294584

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Sept, 1,1942. . -
c. l.. THOMAS d
Filed Jan. 30. 1939
" _ 2,294,584
Patented Sept. 1, 19,42
UNITED STATE s mi“nur> orifice
noN ons
Chicago, -Ill., assignor to
Charles L.
Universal Oil Products Company, Chicago, lil.,
a corporation of Delaware
Application .tammy so, 1939, serial No. 25am
claims. ` (ci. 1st-49)
This invention relates particularly to the man
ufacture of gasoline from hydrocarbon oils heav
ier than gasoline and is more specifically con
cerned with a process which provides for convert
ing hydrocarbon oils of a higher -average boiling
point and a higher speciñc gravity than gaso
line, and which contain hydrocarbonsj'that are
not readily vaporized under the conditions em
jêcting the charging stock substantially under-
liquid phase conditions to contact with a crack»
ing catalyst at a lower temperature and a higher
superatmospheric pressure relative to the tem-,
pe'rature and pressure employed when catalyti~a
cally cracking` clean readily vaporizable stocks
so .that the catalyst is continuously subjected to
the washing action'-- of the liquid materialswhile
the processing is taking place and the amount
ployed when catalyticallycracking clean vapor- '
of carbonaceous materialsl deposited upon the
ous stocks, to lower speciñc gravity and lower 10 catalyst is substantially reduced with provision
average boiling point hydrocarbons than the
for removing the coke forming materials in either
charging stock and/ or gasoline of good antiknock
a coke chamber or a separating chamber or both
properties, and, in addition, gases relatively rich
after the first stage and further provisions made in polymerizable olefìns.
for Pcatalytically cracking the clean vaporous
`The charging stock for catalytic cracking proc
» stocks produced,k in the ñrst stage in a second
esses preferably comprises a gas-oil or a readily stage. In addition, it has been found that hy
vaporizable hydrocarbon oil because it has been
drocarbon oils subjected- to such treatment yield
found desirable to carry the reaction out sub’
substantially more light oils and/ or gasoline than
stantially under vapor phase conditions. In
is obtained in any of the known processesiwhich
other processes the charging stock, which con-' 20 operate on the vapordus fractions obtained.Y from
.tains relatively high-boiling, non-vaporizable
the hydrocarbon charging .stock only. The pres
ent invention.~further provides Afor recycling a
portion of the relatively high-boiling liquid con
as cooling oil followed by fractionation of the `
version products produced in ‘the process by com
commingled materials> to separate a gasoline 25 Amingling the same @With the charging stock in
fractions, is commingled with the conversionv
products from the catalytic cracking -reaction
product, an intermediate fraction which may be
substantially completely vaporized and which is
good starting material for catalytic cracking in
"the vapor phase,- and non-vaporizable residue.
` order to materially reduce the coking tendency`
of the charging stock.
In one specific' embodiment the present inven
tion comprises subjecting relatively heavy reñux
In the latter process, however, the yields -ob 30 condensate to catalytic cracking in substantially »
tained do not correspond to the optimum yields . liquid phase in a primary step„further treating
from a given charging stock, and it is the pur- ,
the products to separate Ivapors from the non
pose of this invention to improve the yields of
vaporous residue and recovering the latter as
gasoline by subjecting the relatively _high-boil
coke, subjecting said vapors to catalytic cracking
i ing, non-vaporizable hydrocarbon fractions in 35 in a second stagegicooling the cracked products
lthe charging stock, together with non-Vaporiz
from the second stage by introducing relatively
light reñux condensate thereto, subjecting the
mixture of cracked products and cooling oil to
This invention, therefore, provides an improved
fractionation along with charging oil to produce
process for catalytically cracking high-boiling 40 overhead vapors of gasoline boiling range which
hydrocarbons in two stages, the ñr‘st stage being
are condensed and collected, relatively light re
v carried out substantially under liquid phase -con
ñux condensate used as said cooling oil, and
ditions and the second stage substantially under
heavy reflux condensate cracked in said primary
' able conversion products produced in the process,
» to catalytic conversion in the liquid phase.
vapor phase conditions with provision for sep
aration of non-vaporous residue from vaporous
components between the two' stages.
It has been found that hydrocarbon oils con
taining substantial quantities of relatively" high
boiling fractions may be converted to oils of a
The outline of the process given in the preced
ing paragraph will be amplified in the following
description to indicate its important features in
greater detail by describing the characteristic
50 operations in connection with the attached dia- l
relatively lower average boiling point and lower
specific gravity than the charging stock by cata
lytic means,; and that the catalytic reaction may
be so regulated that relatively small quantities
of carbon are depositedupon the catalyst in 'the'
nrst stage. This may be accomplished by sub- 55
grammatic drawing. ,The drawing illustrates one
specific form of apparatus in which the process. .
of the invention may be conducted.' However,
the application of the features of the invention-
to other speciñc types of apparatus will be readily
apparent to' those familiar with the catalyticv
cracking art, and the obvious departures from
the modifications and the specific embodiment
of the invention, above described, are entirely
within the scope of the broader features of the
process herein provided.
for example, when employing silica composited
with 15% alumina. This alumina is varied for
best results under specific conditions over a rela
tively wide range, for example, from 2% to 50%
or alumina may be'employed as the major in-`
gredient and the silica varied over substantially
thesame range as the alumina, i. e., 2% to 50%.
-, The accompanying diagrammatic drawing -il
lustrates one specific form 0f ppparatus in which
the >process of the invention may be successfully
rough average, good results are usually obtained,
Catalysts of this character may be initially pre
Referring to the drawing, heating coil I is dis-‘
posed within a furnace 2 by means of which the
10 pared in any of several different manners and
subsequently dried. 'I'he preferred catalyst is
’ prepared by precipitating silica hydrogel from'a
required heat is supplied to the commingled oils
. solution of sodium silicate by acidifying with an
passing through the heating coil to bring them
acid, such as hydrochloric acid, for example, sub
to the desired temperature, preferably at a sub
15 sequently treating and washing the silica hydrogel
stantial superat‘mospheric pressure. In the par
ticular case here illustrated, it is preferred that
the heat supplied to the commingled oils passing
to remove substantially all of the alkali metal
ions, suspending the puriñed silica hydrogel- in a
solution of aluminum salts and depositing the
through heating coil Iv be sufficient to 'raise them l
to the desired temperature but that the time re 20 alumina hydrogel upon the suspending silica by
the addition of volatile basic precipitants, such
quired in reaching such a temperature be rela
as, for example, ammonium hydroxide, ammonium
tively rapid in order to suppress any thermal
carbonate, or ammonium sulphide. After the
cracking reaction.
u'id phase, are vdischarged from heating coil I 25 purified
is dried,
through line 3 and valve 4 into catalytic reactor
The heated products, substantially in the liq
at a temperature of approximately 850
to 1000° F.
Although the present process has been found
5 wherein they are contacted with a cracking
catalyst disposed therein.
hydrogel has been deposited upon the
hydrated silica hydrogel, the material
formed into pellets, when desired, and
Preferably and in the case here illustrated,
to operate very effectively in catalytically crack
catalytic reactor 5 comprises a plurality of small 30 ingV petroleum oils when employing a catalyst
A diameter reactor tubes 6 connected in parallel
consisting of silica composited -with 15% alumina,
between upper and lower headers 'I and 8 and' is
disposed within a -heating or cooling zone 9.
the process is not limited to this particular com
position of catalyst but may employ other com
Catalytic crackingA is an endothermic reaction
_requiring heat and, therefore, in order to obtain
posite catalysts of a refractory character, such
as, for example, silica composited with a com
-best results heat must be supplied to the material
ponent selected from the group comprising zir
undergoing conversion within reactor 5. It has
conia, vanadia, alumina-zirconia, or alumina
been found that best results are usually obtained
and acid-treated clays may also be em
when employing fluid heating means which pref
The catalysts referred to above are‘not
erably comprises hot combustion gases-which may 40 exactly equivalent
in their reaction and are not
be introduced to zone 9 through duct I0, passed
to be considered as absoluteV substitutes one for
in indirect heat exchange relationship with the
materials passing through reactortubes 6, after
the other, which fact will be more or less ap
parent to those skilled in the art.
In the particular case here illustrated, when
which they are discharged from the upper por
tion of zone 9 through duct I I.
l ,
45 the catalysts are reactivated the now ofA hydro
In catalytic endothermic reactions, such as
carbon oil is stopped and suitable reactivating
catalytic cracking, carbon deposits upon the cata
gas mixtures at an elevated temperature and
lyst atv a relativelyrapid rate and tends to de
containing regulated quantities of oxygen are
crease the catalyst activity, this fact being even
introduced to catalytic reactor _5 through line >
more apparent when the charging stock comprises 50 I2, valve I3, and line 3. The reactivating gases
relatively high-boiling, non-vaporizable residual
pass through reactor tubes 6, and due to oxida
t ' hydrocarbon oils. In order to obtain best results,
tion the carbon deposited upon the catalysts dis
' relatively short operating periods are employed;
posed therein is caused to burn. The resulting
i. e., the catalysts are subjected to contact with
mixture of Acombustion gases and reactivating
the materials undergoing conversion for a'rela 55 gases is discharged from reactor 5 through line
tively short time and are then reactivated in ap- `
I4 and is directed through line I5 and valve I6
Iproximateîy the same length of time. In this »
case it is preferred that a plurality of reactors
to storage or further use" as a reactivating' gas '
mixture or a portion or all >may be cooled and
be employed, each disposed within a separate~
recirculated as the reactivatingggas mixture or
heating or cooling zone,4 and in order that the 60 the whole may be discharged to the atmosphere
operation may be made continuous, reactivation
as desired. AWhen reactivating the catalyst
' may be accomplished in some of the reactors While>
the others are processing.
Although I have found it advantageous to em
ploy a reactor of the type described above, vari
ous other kinds, such as, for example, the cham
-ber type, may be- employed without departing
_ the reaction is exothermic and, therefore, suit
able means must be employed to dissipate the
heat generated therein. In this case it is pre
65 ferred to employ cooled combustion gases which
are supplied to zone-9 through'duct I0, passing
therethrough in indirect heat exchange relation
from the broad scope of the invention. Catalysts , ship with the ñow of reactivating' gases in re
which have been found to be highly eiflcient in
actor tubes 5, and are discharged` therefrom
the catalytic cracking of hydrocarbon oils con 70 through duct II. The vaporous and liquid con
sist in general of uniform sized pellets of specially , version products“ are discharged from reactor 5
prepared silica composited with the alumina, the
through line I4 and valve I‘I and may be directed
amount of alumina being varied lto suit 'require
all or in part through valves I8 and I 9 to coke
ments depending upon the stock to be treated
chamber 20. However, .when the conversion a
and the operating conditions employed. As a 75 products from- catalytic reactor 5 lack sufllcient
[email protected] l ,
low pressure employed in this catalytic reaction,
ieat >to coke material deposited within coke
chamber 20, additional heat may be acquired by
and in'order to reduce- the eñective pressure on
the hydrocarbon vapors, steam may be intro-f
neans of furnace'24. Inthis case, all or a por
duced to `.the vaporous products either before
heating coil 50 by way of line 5t and valve 55
or after heating coil 50 by way of line- et and
;ion 0f the conversion products in line I4 are
iirected through line 2| and valve 22 to heating
:oil 23.l Heat _is supplied to the conversion prod
ucts passing through heating coil 23 by means
In the case here illustrated, catalyticvreactor
of furnace 24 and they- are discharged therefrom
41 is constructed similarly to catalytic reactor 5
through line- 25 and valve 26 into line ld and
and lconsists of relatively small diameter reactor
introduced to coke chamber 20, as previously de
tubes 58 connected in parallel between upper and
lower headers 59 and 60 and disposedv within a
The liquid conversion products introduced to
coke chamber 20 in commingled state with the
vaporous conversionproducts are reducedto sub
stantially dry coke therein, and the' vaporous
conversion products, together with the vapors
heating or cooling ,zone 6i. ~
As in the case of
catalytic reactor 5,. the preferred form of heat
ing the materials within catalytic reactor 4l is
by fluid heating means. Hot combustion gases,
comprising the iiuid heating means, may be in-evolved within coke chamber 20, are withdrawn
troduced to zone'6l by Way of duct 62, passed in
from the upper portion thereof through line 2l
indirect heat exchange relationship with the va
and may be introduced allor in part to separat
materials passing through reactor tubes ,
ing chamber 3| by way of linel 28, valve 29, and 20 porous
5t, and discharged from the upper portion of ,
line 30, or the vaporous materials may be di
zone 6i by Way of duct 63.
rected through valve 32_ and treated, as subse
Catalysts are preferably employed in catalytic
quently described,
reactor rtl which have been found to be highly
Preferably, a plurality of coke chambers are
efficient in the catalytic cracking of hydrocar
employed, although only one is shown in the 25 bon oil vapors to produce optimum yields of
diagrammatic drawing. in order that the coking
gasoline. The preferred catalysts for edecting
operation may be made continuous with respect
catalytic" cracking of vaporous materials consist
to the balance of the apparatus by alternately
in general «of pellets or granules of the same _
coking and cleaning eachgchamber. In the case
materials as were previously described, and, also,
lhere illustrated, before coke chamber 20 is cleaned 30 the methods previously disclosed for preparing
of the coke deposited therein, steam is preferably
catalysts are employed for preparing these cata»
introduced through line 33 and valve 34 in order
to purge the vessel of hydrocarbon vapors.
,Th activation of the catalysts disposed vwithin
In case it is desirable to make liquid residue
reactor dil is accomplished by stopping the ñow
instead of coke, coke chamber 2d may be by 35 of vapors to reactor ¿tl by means of valve ¿it and
.passed and the conversion products in line ld ' introducing suitable reactivating gas mixtures
directed through line 28, valve 35, and line [email protected]
at an elevated temperature and containing reg
to separating chambery 3l. The preferred meth
ulated quantities of oxygen by way of line td,
od, however, consists of introducing' the con
valve 65, and line 2l. The reactivating gases
version products to coke chamber 2d and sup 40 pass through reactor tubes 5il,'and due to oni
plying the vaporous materials from coke cham
dation the carbon deposited upon the catalysts
ber [email protected] to separating chamber 3l. ln separating
disposed therein is caused to burn. The result
chamber 3l thehigh-boiling, coke-forming ma
' ing mixture of combustion gases and reactivating
terials carried over with the vaporous materials
gases is discharged from reactor dl through line
from coke chamber 2d are separated from the 45 SS and is directed through line ti and valve [email protected]
vaporous materials and collected in the bottom.
to storage for further use or elsewhere las de
The high-boiling, coke-forming materials are
directed from the lower portion of separating
sired. Duringreactivation, in order to dissipate
"the heat generated in the exothermic reaction,
cooled combustion gases are preferably supplied
chamber 3i through line 3S and valve 3l to pump
3d which discharges through line 39, and all or
a `portion of these materials may be directed
through valve ‘it to cooling and storage. In the
preferred process, however, these materials are
returned to coke chamber 2t by way of line di»
and valve d2 in order that they may- be reduced 55
to zone div by ,way lof duct t2, passed in indirect'
heat exchange relationship with the reactivating
gases in reactor tubes 58, and discharged by way
of duct
In order that the catalytic cracking reaction
carried out in catalytic reactor ¿ll may be made
lcontinuous with respect to the balance of the
The vaporous materials separated in separating I equipment, and because of necessity the reactors
chamber di are withdrawn from theupper por
are operated on a relatively short-time schedule,
tion thereof through line d3 and are directed
a plurality of reactors are preferably employed,
through valve @d into line 2l. The vaporous so each disposed within a separate -heating or cool
materials in line 2l are preferably heated to
ing zone. In this case the reactivation is car
the desired reaction temperature in furnace 5l,
ried out in some of the reactors while the others
however, when and if these materials are at the > are processing. Although the type of reactor
desired reaction temperature they may' be di
described above hasbeen found to have 'many
rected through valve t5 and valve dâ to reactor 65 advantages when employed in this particular
dl. Preferably, however, these vaporous materi
als in line 2l are subjected to heating in furnace
5l, this being accomplished by directing them
' process, various other types of reactors 'may ,be
employed without departing from the broad
scope of the invention. The conversion products
through line d8 and valve di? to‘heating coil 5d.
discharged from catalytic reactor ‘lll are di
The heated> materials are` discharged. from -heat 70 rected through line 66 and valve 69, cooled to a
ing coil 5t through line 52 and valve 53 into
relatively low temperature by commingling with
line 2i! by means of which they.are supplied l
to reactor ll‘ï, as previously described.
the same a suitable cooling- oil and the conver
sion products, together with the cooling oil
introduced to fractionator it.
reactor di in the vapor state under the relatively
In order to maintain the charge to catalytic
2,294,584 '
Charging stock for the process», preferably
'comprising a hydrocarbon oil heavier than gaso
line, is introduced through line 13 and ,valve 14
to pump 15 which discharges 'through line 16
'I'he preferred range of operating conditions
which may be employed in an apparatus such as
illustrated and above described to accomplish the
and all or a portion of the charging stock di
rected through valve 11 into fractionator 10.
The preferred method, however, for introducing i
charging stock to the process consists -in com-`
mingling at least a portion ofthe charging stock
in Í‘line 16 with the conversion products dis
charged from catalytic reactor 41 in line 86
as cooling oil.y 'I'hi's may be accomplished by
desired result is approximately as follows:
The heater to which the heavy reñux con
densate is supplied may employ an outlet tem
perature ranging, for example, from r100 to 1100°
F. and a superatmospheric pressure of from less
than 200 to r100 pounds or more per square inch.
Substantially the same conditions of temperature
and pressure are maintained on the first catalytic
cracking stage as are employed onthe outlet of
directing all or a portion of the charging stock _. -the heating coil to which the heavy reflux con
in line 16 through line. 18, valve 19, and line
densate is supplied. The coke chamber and
15 separator may employ a superatmospheric pres
|05 into line 66.
_ In -fractionator 10, from the commingled ccn
sure substantially the same or somewhat reduced
4relative to the superatmospheric pressure em
pl yed on the outlet of the ñrst catalytic crack
version products and cooling oil- (and when oil
other than charging stock is employed as cool
ing oil, thecharging stock), fractionated vapors
in stage. The heating coil to which the clean
of the desired end boiling »point are separated 20 vaporous materials from the separator are sup
from the higher boiling liquid conversion products
plied may employ an outlet temperature ranging,
and the higher boiling fractions of the charging
for example, from 8'00 to 1200° F. and a superat
mospheric pressure of from 20 to 100 pounds ory
Fractionated vapors of the desired end boiling
more per square inch. "I'he conversion products
point are directed from-- the upper portion of 25 discharged vfrom the second catalytic cracking
fractionator 10 through line 85 and valve 86 to
stage are preferably cooled to a temperature
condenser 81. The resulting gas-containing dis
ranging, for example, from- 600 to 800° F. or at
tillate, together with undissolved and uncon
least to a temperature suiiiciently low to substan
densed gases discharged from' condenser `81, are
tially arrest any thermal cracking reaction. The
directed through line 88 and valve 89 to receiver 30 fractionator following thel second stage may
90. Undissolved and uncondensed ~ gases col
utilize a pressure substantially the same as that
lected and separated in receiver 90 are directed
`employed at the outlet of. the second catalytic
from the upper portion. thereof through line 9|
cracking stage.
and valve 92 to collection and storage or `else-H
Aslan example of one specific operation of the
where as desired. A portion of the distillate col 35 process as'it may be accomplished in an apparatus
lected and separated in receiver 90 is directed
such as illustrated and above described is ap
through line 93 and valve 94 to pump 95 which
proximately as follows:
f discharges -through line 96 containing valve 91
into the upper portion of fractionating zone 12
Heavy _reiiux condensate produced within the
system was subjected to contact Ain thefliquid
for refluxing and cooling therein. The balance 40 phase with a silica-alumina cracking catalyst at
ofthe distillate collected and separated in re
. a temperature‘o'f apprôximately 930°1F. and under
ceiver `90 is ‘directed from the lower portion
thereof through line 98 and valve 99 to stabiliza- s
tion or to storage yor _to further treatment as
a superatmospheric pressure ofapproximately 300
pounds per square inch. The conversion products
from this stage were introduced to a coking zone
45 operated at a superatmospheric pressure of ap
The higher boiling hydrocarbons, comprising
-proximately 75 pounds per square- inch wherein` i
fractions of the conversion products and frac
the non-vaporous residue was reduced to sub
tions of the charging stock whose average boil
stantially dry coke. The vaporous materials re
ing point is above that of the fractionated vapors,
moved frorn the coking zone were introduced to a.
are selectively condensed as light and heavy re 50 separating zione, operated under vsubstantially
¿flux condensate in‘fractionator 10. The light i the sa'me superatmospheric pressure as thecok
" reflux condensate is withdrawn from an inter
ing zone,k toA remove entrained liquids from the
mediate point in fractionator 10 and is directed `
vaporous materials and the former returned to
through line |00 and valve |0| to pumpA |02.
the coking zone. The vaporous materials were
Pump |02 discharges through line |03 and a 55 removed from the separating zone and subjected
portion of the refluxcondeiîsate in line |03 may
lto contact in the vapor state with a silica
be directed through line |05 and valve IUS-and
alumina cracking catalyst at aA temperature of
commingled with the conversion products in line
approximately 900° F. and under a superatmos
66 as cooling oil prior _to their introduction` to
pheric pressure of approximately 40 pounds per
fractionator 10. The balance or all of the light 60 square inch. The conversion products from this
reflux condensate in line |03 may, when desired,
second catalytic, cracking stage were cooled to
be directed through line |01 and valve |08 into
approximately 650° F. by commingling with the
line 21 for subsequent conversion -in commingled
state with the vaporous materials removed from
separating chamber 3|'. Light reflux condensate
is preferably employed as a refluxlng and cool
ing mediumin separating chamber 3|, and this
same light'reñux condensate produced as herein
after described.
The conversion products, to
65 gether with the cooling oil, were introduced to a
fractionator operated at substantially the same
superatmosphe'ric pressurel as was employed on
may be accomplished by directing at least a por
the outlet of the last mentioned catalytic crack
tion of the light reflux condensate in line |03
y ing _stage and was subjected to fractionation
through valve |04 into the upper portion thereof. 70 therein in commingled state with the charging
The heavy reflux condensate collected in the
stock comprising a 25° A. P. I. gravity Mid-Con
I lower portion of Iffractionator 10 is withdrawn
tinent topped crude oil t'o separate fractionated
therefrom and supplied to heating coil | for treat
va`pors of the desired end boiling point from the
' ment, as previously described, by way of line 80,
valve 8|', pump 82,_line 83, and valve 84.
higher boiling liquid conversion products and the
75 higher boiling liquid fractions of the charging
2,294,584 Y
process, fractionating the commingled conver
sion products and charging stock to separate gas
and gasoline from the higher boiling hydrocar
bons, recovering said gas and gasoline as prod
ucts of the process, selectively condensing and
collecting said, higher boiling hydrocarbons as
light and heavy reflux condensate, subjecting
said light reflux condensate to ,conversion in
commingled state with said vaporous components
stock and the fractionated vapors recovered as
a product of the process. The higher boiling liq
uid conversion products and the higher boiling
liquid fractions of the charging stock were selec
tively condensed as light and heavy reflux con
densate and the latter subjected to conversion
in theiirst mentioned catalytic cracking stage,
as previously described. ' A portion oi the light
reflux condensate was commingled with the con
in said lsecond stage, and subjecting said heavy
version products from the second mentioned 10 reñux condensate to conversion in said first stage.
-cracking stage and the balance of the light re
3. A conversion process which comprises sub
iiux condensate subjected -to conversion in the
jecting heavy hydrocarbon oil to relatively mild second mentioned catalytic cracking stage. This
cracking underl suiilcient superatmospheric pres
operation yielded approximately 65% of 81 octane
"ure to maintain a substantial portion thereof in
number gasoline by volume of the charge and 15 liquid phase and in the presence of a cracking
approximately 60 poundsof coke per barrel of
catalyst comprising silica and alumina, separat
ing the thus treated oil into vapors and residue,
I claim as my invention:
subjecting the separated vapors to further cata
1. A process for the production of hydrocarbon
lytic cracking at higher temperature and under
oil of lower average boiling point than the charg
lower pressure than and independently of said
ing stock and gas of relatively high polymerize
heavy oil, íractionating the resultant conversion
able olefin content from hydrocarbon oil with an
products to form light reflux condensate and a
average boiling point above that of gas-oil, which
heavier reflux condensate, supplying said heavier
comprises subjecting heavy reilux condensate,
reflux condensate to the first mentioned cracking.
produced as hereinafter set forth, to contact,` in 25 step, and supplying thev light reflux condensate
the liquid phase'at a temperature ranging from
to the second mentioned cracking step.
r100 to 1100° F. and under a superatmospheric
4. A process for the conversion of heavy hydro
pressure of from less than 200 to ’700 pounds per » carbon charging stocks which comprises subject
square inch, with a silica-alumina cracking cata
ing heavy reñux condensate, formed as herein
lyst in a primary stage, separating the conver->
after. set forth, to relatively mild cracking in a
sion products discharged from said primary stage . primary stage under sufficient pressure to main
into vaporous components and non-vaporous
tain a substantial portion thereof in liquid phase
residue andrecovering the latter as a product of
and in the presence of a siliceous cracking cata
the process, subjecting said vaporous components
lyst,'separating the thus treated reiiux conden»V
to contact, in the vapor phase ata temperature 35 sate into vapors and residue, subjecting the sep
ranging from 800 to 1200o F. and a pressure of
from> substantially atmospheric to 100 pounds
per square inch, with a silica-alumina cracking
" arated vapors to further catalytic cracking in a
secondary stage at higher temperature and under
lower pressure than and independently o! the
reflux condensate. in the primary stage, >frac
tionating the resultant conversion products in
ladmixture with the charging stock for the proc
ess to separate gasoline and» gas and to formv a
light reflux condensate and a heavierreiiux con
catalyst in a second stage, cooling the conversion
products discharged from said -second stage by
, comming‘ling -therewith charging stock for the
process, fractionating the commingled conversion
products and charging stock to separate gas and
gasoline from the higher boiling hydrocarbons,
densate, supplying said heavier reflux condensate
recovering said gas and gasoline as products of 45 to the primary stage and supplying said light
the process, selectively condensing and -collecting
reflux condensate to the secondary stage.
said higher boiling hydrocarbons as light and
5. The process> as deñned in 'claim 4 further
heavy reiiux condensate, subjecting said light re- .
characterized in that the 'charging stock is com
flux condensate g to conversion in commingled
mingled with said conversion products promptly
state with said vaporous components -in said sec
upon discharge of the latter from the secondary '
ond stage, and subjecting said heavy reflux con
stage whereby to quench said products.
.densate to conversion in said ñrst stage.
6. The process
as denned in claim 4 further'
the production of hydrocarbon
- 2. Aprocess for
oil of lower average boiling point than the charg
ing stock and gas of relatively high polymeriz
, characterized in that the catalyst in Íboth said
able olefin content from hydrocarbon~oil with an
average boiling point above that of gas-oil, which
cracking stages comprises a silica-alumina'com
7. A conversion process which comprises sub
jecting heavy hydrocarbon oil to relatively mild
comprises subjecting heavy ren'ux condensate,
cracking under suiilcient superatmospheric pres
produced as hereinafter set forth, to contact, in
sure to maintain a substantial portion thereof in
the liquid phase at a temperature ranging from 60 liquid phase andin the presence or a cracking
'700 to 1100° F. and under a. superatmospheric
catalyst comprising silica and zirconia, separat
pressure of from less than 200 to '700 pounds per
‘ing the thus treatedjoil into vapors and residue,
square inch, with a silica-zirconia cracking cata.
~ subjecting> the separated vapors to further cata
lyst in a primary stage,` separating the conver
lytic cracking at higher temperature and under
sion products discharged from said primary stage
>pressure than and independently of said
into vaporous vcomponents and non-vaporous
oil, fractionating the resultant conversion
vresidue and recovering the latter asa product ofl
products to form lightrerlux condensate and a
the process, subjecting said vaporous components
- heavier refiux condensate. supplying said heavier
to contact, inthe vapor phase at a temperature
reflux condensate to the first mentioned cracking
ranging from 800 to 1200° F. and a pressure of
, 70 '
from substantially atmospheric -to 100 pounds per
square inch, _with a silica-zirconia cracking Ycata- "
lyst in a .second stage, cooling the conversion
products discharged from said second stage by
colina therewith charging stock for the 75
step and supplying said light reflux condensate -
to the second mentioned cracking step.
8. The process or claim 3 further characterized
in that the catalyst contains zirconia.
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