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Патент USA US2406555

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Aug. 27,- 1946.
H, z, MARTIN
' 2,406,555
PROCESS FOR THE CONVERSION OF HYDROCARBON OILS
Filed Sep'l’..A l5, 1941
.355V
2 sheets-snee; 1
`
Patented Aug. 27, 1946
2,405,555
UNITED STATES PATENT ` OFFICE
2,406,555
PROCESS FOR THE CONVERSION 'OF
HYDROCARBQN lOILS
Homer Z. Martin, Elizabeth,- N. J., assignor to
Standard Oil Development Company, a cor
poration of Delaware
_
`
Application September 13, 1941, Serial No. 410,657 '
3 Claims.
(Cl. 196-'507
l
2
This invention relates to the catalytic conver-->
it has also been suggested to lcarry out the coking '
sion of hydrocarbon oils and pertains `more par
treatment in the presence .of a relatively inert
ticularly to» a process for converting heavy crude
solid material which forms a carrier for the coke
oils, such as topped or reduced crude or other
and from which the coke maybe -bu-rnedat .fre
residual‘oils, into motor fuel constituents.
5 quent intervals. In other cases, when operating »
It has been heretofore proposed 'to crack oils
to .form a coke residue it has been the Ípractice
in the presence of a vcracking catalyst to form
'to collect .the coke „formed in .separate coking
gasoline of relatively .high octane rat-ing.
According to one general mode of operation, the
oil in vapor form- is passed through a cracking _l0
vessels from Which the coke may be, .removed
by mechanical means.
.
A » -
In all of the above cases, the treatment of
zone containing -a ñxed mass of catalyst7 prefer'ably in the 'form of pellets or molded units, lo-
this residual ,fraction for _production of additional
quantities offgasoline has required a considerable
cated Wit-hin the .reactor and supported on a
investment in additional equipment.
.
perforated tray or a plurality of trays. During
One of the primary objects of thevpresent »in
the cracking process the activity of the catalyst '11:5 vention yis to provide .a process .for catalytically
rapidly depreciates due to the formation oicar- t
craeking crude oils to the desired vconversion in
a single stage without .the necessity .of first sep
bonaceous deposits. In View of this, .it is neces
sary in xsuch operations to interrupt the crack#
arating a .heavy residual fraction therefrom.
A further important object .of the invention vis
ing process frequently .and regenerate ‘the :cata
to provide .an .improved process for cracking crude
lyst mass by burning the carbonaceous deposits.
yoils or residual .oils which Will >require .less >etpiip
therefrom. In order to avoid the >forma-tion of
inent .for .a .cracking plant :of .given capacity and
excessive -coke deposits, which in turn reduces
>for va given quantity of .motor fuel produced.
the productive capacity of the cracking chamber,
A fur-ther secondary object of the invention
it has been the practice to first vdistill and frac
tionate 'the crude Ioil and to pass only the cleanl -25 is to provide an improved process and apparatus
vapors in contact with the catalyst and to reject
for cracking residual oils which will .take .better
a heavy residual Ífraction which tends to form
advantage; Yof the heat liberated during .the re
excessive amounts of coke during the cracking
_generation'of the >catalyst .for carrying out the
process.
cracking process..
This method Vof >operating-not only re-
quires the provision of diS'tilli-ng equipment for '30
Y
1 f
Other more .specific _objects oi' the .invention
preparing a clean feed stock .for the cracking
Will be apparent from the more .detailed descrip
'process but also requires the `rejection of a sub-
tion thereinafter.
f
v .
'
v
-
stantial amount of the original feed .in the form
- In accordance with the broader phases of the
of a residue which is not normally suitable for
present invention, ac-ruderesi-dual fraction, such
cracking treatment for the production of Ihigh 35 as a topped -or reduced crude, or, in certain cases,
octane `gasoline Without additional processing.
the `entire crude, is contacted with ahot- adsorp
This rejected fraction may amount to from 5%
-tive catalyst in subdivided state at a materially
to 40% of the original crude, depending upon the
nature of the `crude oil. This residual product
higher temperature level than the oil, the Íamount
of catalyst being ycontrolled with respect to the
'in many cases is consequently marketed >as fa, »40 temperature thereof so that the >oil upon ‘contact
heavy fuel oil.
with the catalyst is promptly converted into va
However, this residual fraction contains a substantial portion .of oil 'which can be :converted
into high-grade Ygasoline with additional process-
p'ors, except for some residual oil which is `corn
pletely adsorbed by the `catalyst withoutcausing
the latter to become tacky .or sticky. V- The -re
ing. For example, it has been the practice ,in 45 `sult-ing mixture,- therefore, consists of relatively
some cases to sub-ject this heavy residual rrac`dry oil 'vapors 4and discrete particles of <catalyst
tion to a yseparate yand :independent (cracking 'or
containing the heavy constituents» adsorbed
viscosity breaking treatment to convert the same
therein.
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y
into the maximum of overhead vapors suitable
The resulting ydispersion Iof. »catalyst powder
for .further cracking under êcon'ditions controlled 50 containing the residual constituents adsorbed
for .the product-ion of improved octane gasoline.
therein and the oil vapors .is then passed through
In other leases; it has been the practice to con
vert all of this residual fraction into overhead
vapors suitable vfor ,further cracking with the ex
ception of the Ycoke residue. >In the latter case,
va cracking .chamber in which the desired .con
Version is accomplished.
. `
. '
As distinguished from viscosity breaking oper>atiQns of the type hereinbefore described, the
2,406,555
4
3
l designates a charge line through which the oil
to be processed is introduced into the equip
present invention contemplates the conversion of
Va substantial'portion amounting to at least 30%
of the residual oil into gasoline constituents of
‘ ment.
high octane quality.
` a residual oil, such as a crude petroleum, `or
.
a residual petroleum, such as a topped or re
, 'I'he cracking process is preferably carried out
duced crude from which some of the lower
under conditions such that the catalyst is re
tained ,within the cracking zone for a period
substantially longer than the length of time the
oil vapors are retained within the cracking zone.>
This makes possible a greater utilization of the
boiling constituents, such as gasoline, kerosene
or part of the gas
distilled.
oil, ' have been initially
The oil so introduced is preferably
initially preheated by heat exchange with hot
For example, the oilso introduced may be forced by feed pump Il
> products from the process.
i catalvst between -regenerations’ and permitsV re
taining the catalyst within the cracking zone
until its activity has dropped to a point Vwhere
regeneration of the catalyst is desired.
'
` This retention of the catalyst within the crack
This oil may be, as previously described,
` through line I2 toa trimming coil I3 located
» in the top of product fractionator I4 in which the
y15
ing zone for a period substantially longer than
the time of residence of the oil vapors therein Y
cracked products are fractionated. The oil after
passing through the coil I3 may be passed
through line I5 to a second heat exchange coil
IB located in the bottom portion of the frac
can be accomplished by passing the dispersion
tionating ytower I4 or in a heat exchanger as
upwardly through a vertical cracking chamber
and regulating the velocity of the oil vapors so 20 sociated with the bottom portion of the frac
tionating tower. -The oil after Vpassing through
that there is a decided tendency for the catalyst
the second preheating coil I6 may then be passed
to settle or separate from the oil vapors. By reg
through line I1 to a heat exchanger I8 wherein
ulating the velocity of the oil vapors within the
it passes in heatA exchange relation with spent
controlled limits, a dense phase of catalyst can
be retained within the cracking chamber and 25 regenerating gases removed from the regenerat
ing zone, as hereinafter described. The oil after
`at the same time the oil vapors may be utilized
passing through the heat exchanger I8 is passed
as a transfer medium for the introduction of the
through line` I9 to a heat exchanger 20 where
catalyst therein.
it passes in indirect heat exchange relation with'
Following the cracking process. the catalyst is`
l
separated from the cracked products either with 30 'hot catalyst undergoing regeneration.
The oil after passing through heat exchanger >
in or without the cracking zone and the cracked
20 is transferred through line 2l to a second heat
productsv fractionated in a conventional manner
exchanger 22 wherein it picks up additional heat
to segregate the desiredproducts.
‘
from hot catalyst undergoing regeneration as
The catalyst so separated is then regeneratedV
y
-Y
_
to remove the carbonaceous deposits formed dur 35 later described.
ling the cracking treatment. The regeneration
lof the catalyst is preferably carried out at the
`maximum premissible temperature which will
`avoid permanently impairing the activity of the
. When operating on total crudes containing
substantial amounts of gasoline, it may. be de
sirable in some cases to ñrst distill thestraight
run gasoline. For example, in lieu of passing the
ïcatalyst so as to make available for the cracking 40 crude loil in heat exchangewith‘ cracked prod
ucts in the product fractionator I3, crude oil in
v‘operation the maximum amount of heat liberated
troduced through line I0 may‘pass through line
Iduring the regenerative treatment and the cat
23 to a crude stillZlI wherein the oil'is heated
alyst so regenerated is immediately contacted
‘ to a temperature of from 400° F. to 600° F., suf
`with the oil while at substantially its maximum
regenerating temperature. In order to operate 45 ficient to vaporize the lower boiling fractions.
The preheated oil then `discharges into a sepa
the regenerating chamber at the maximum tem
perature level. it is important vto avoid localized ' rating chamber 25 wherein the vapors formed
separate from the remaining liquid. The vapors
overheating of the catalyst within the regener
in separator 25 pass overhead to a condenser 26
§ating zone. This is accomplished, `according to
one of` the specific phases of the invention. by 50 wherein the straight-run` gasoline vapors or
other low boiling vapors are liqueñed. Products
¿constantly agitating or churning the catalyst
from condenser then pass to a distillate receiver
within the regenerating zone, and. according to
21. Liquid is Withdrawn from yseparator .25
one of -the additional'phases of the invention,
through line 28 which merges with feed line I'I.
ïthis agitation or churning is accomplished by the
flow of the regenerating gas through the re 55 The oil duringV its passage through the heat
exchangers and crude still hereinbefore described.
igenerating zone as hereinafter described. While
¿this method of regeneration has been previously ` or any combination thereof, is preferably pre
heated to a temperature of from 400° F. to an
ïproposed, it ñnds particularlapplication in the
incipient cracking temperature, such as, for ex
îpresent process wherein it is important to oper
ate the regenerating zone at the maximum tem 60 ample, to a temperature of from ’700° F. to 800° F.
The oil after being preheated to a temperature of
‘peraturelevel'without local overheating in order
from 400° F. to 800° F. by passing through one
§to make available the `maximum heat from the
iregeneration for the cracking process.
'
or more of the .various heat exchangers is passed f
through line 29 into which hot regeneratedV cata
,and advantages, the invention will be described' 65 lyst is charged through line 30.
In some cases it may be desirable to maintain
îin more detail in which reference will be made
the oil ‘during passage Ythrough the heat ex
‘to the accompanying drawings wherein
changer vequipment under a pressure consider
Fig. I is a diagrammatic illustration of an ap
ably above the operating pressure Within the
iparatus suitable for carrying the invention into
70 cracking zone. To this' end, the line 29 may be
¿eii'ect, and
provided With a reducing valve 3| preferably
Fig. II is a similar View of a simplified ap
Having set forth the general nature. objects
paratus wherein the total heat requirements for
lcarrying out the process are obtained by direct
contact with hot catalyst.
_located at Va point preceding the catalyst dis'
charge line 30. For example, the pressure on the
oil passing through the preheating equipment
Referring toiFig. I, the reference character I0 75 may range between 50 and 500 pounds per square
lamme-e5 ‘
55
lzlnch,
.the `cracking is zpreferably married
tout below :10;0 :pounds :per.squarev inch, although
«somewhat .higher :pressures 'may ib'e employed :in
«samelca'ses
’
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.
.
J>.The :amount :of :catalyst introduced ‘finito ithe :oil
¿stream fis regulatedatc ‘vaporize @a 'fportion :of the
:oil lwvhi'le .retaining .the Íremainder ßin‘ili'quid ' phase.
The amount of unvaporizable residue, ihowever,
should :not îbe iin fexcess '.o‘f ¿that lw‘hichiican be .
Acompletely adsorbed by ’the catalyst particles
`without causing the catalyst .particles “to äbecome
.adhesive :and 4i’orm :a 44Vtacky, .sticky mass. ' :The
.amount .of ¿such Icatalyst ‘introduced into îthe foil
:vapors 4will Idepend 'upon :the ‘temperature iof :the
:catalyst and lthe :temperature ‘o‘f îthe .foil ¿at the
yplacedzhecatalystisßrnixed‘withithezoii.
.
l
‘EIllre famount 'of .catalyst introduced "into “the-‘oil
¿stream may .range :between .1 .and =45 4parts -zof
catalyst per part fof'oilïby’rveightpdepending upon
'.T-hefstream :of fcracked products :and mil
¿fatter l.passing ‘through #the ¿crack-ing chamber‘ßß `
iis .passed ‘through "Iin'e :3.5k :to Ava primary separator
136 _:for the separation :of 'the catalystk from ithe
.cracked vapcrçproducts. >This:separator¿mayhe
lof îa'ny ‘conventional type :suitable .ì'for .segregation
:of «solidsaffrom v‘gai'ses .fand .ih-as .been îillustrated
.The #catalyst
*the ëformcf ¿a cyclone separator.
removed from the cracked products ¿during pas
-'sage 'through the primary . separator `¿3B ¿discharges
-in-to fa vertical ftube T31 :from `whence .it is ¿passed Y
:to :a regenerating ïchamber, 'as flater described.
’.'Illre `cracked Wapors ‘after çhaving the .bulk `rif
the catalyst'removed therefrom in :the :primary
:separatorîßß v:maybe passedzthrough line §38 tera
secondary ¿separator :39 '.f'or îîurth‘er removal «io’f
¿the ¿catalyst material. l,'Iïhe 'fcata‘lystfseparated ’in
'the :secondary ëseparaltor §39 'discharges Athrough
.line 40 :finto the ¿bottom section «fof ¿the :primary
".th‘e fnature iîof'ftlre- oil,y temperature :of fthe catalyst, '.20 :separator '.36 where it imixe‘s'wîith catalyst sepa’
»thel‘d‘egree'o'f :pretreatment andsother factors. ÍIn
.irated in the 'primary ¿cyclone :36. ’The .bottom
most 1cases îthe 'zratio will .':be ‘lbetween 5 `andt20.
" uThis VYcatalyst may comprise any vradsorptive
:material capable yof :catalytica‘l‘ly effecting the
‘portion fof .the :primary .separator 13.6 may "be ’pro
vided ~with suiiicient “volume ito áform va :storage
.hopper capable of maintaining v'a reserve `supply
y.cra-'cking operation. vSuch ¿material may »com 125 iof catalystîfor 'the process. .Steam for Iother ‘strip
prise, for-.example Anatural clays for -'clays which
`have fb'een .activated Eby «suitable 4Itrea‘tm'ent, Lsuch
as with fa'cid, fto remove :impurities which may
affect vthe fcracking or regenerative 'properties of
¿ping :gas may vbe'iritroduced into the Íbottom 'of
:the separator -36 ‘through line "4| ’to -'strip 'volatile
vcracked 'products ifr'om 'the 'catalyst before‘passin'g
the “same to :the regenerating zone.
'fthe catalyst. .Inï’lieu of‘ïthematural materialßsuc'h 30 z'Ilhe :cracked 'vapors fatter passing throug'h‘ithe
Yas clays, 'the catalyst may :consist `of synthetic
'secondary separator l39 îm’a'y ïbe ‘passed vfto iad'd‘ie
adsorbent materials, such Jas, ¿for ¿exam-ple, I syn
thetic .gels ¿of silica fand-alumina »or silica and
magnesia, alumina, lbo‘ric :oxide fand others.
YThe‘<.cata‘1yst introduced "into the 'oil stream
rshould ïbe in subdivided estate, the size of the
‘particles ranging :from a nne powder, such fas
'400 ‘zmesh> or finer, up to relatively .coarse lgran
ules, such as from 5 to 1Í0.mes`h.
"The resulting ~dispersion "consisting v»essentially .
of oil ’vapors which have been fva‘porized by con
tacting ‘with “the Iho't "catalyst land by «reduction fin
pressure îthrouglhftlre l»reducir-1g valve i3! and 'the
catalyst containing the 'unyaporiza'ble constitu
" 'ents ¿of .ïthe .oil 'adsorbed 'therein "is ipassedithrough
`tional cyclones, electrical‘precipitatorsibag'ñlters,
or l.other ‘separators (not shown) A‘for'furtlrier fpuri
fication. The cracked products fatter separation
¿from :the -natalyst are 'passed ".:fthrough llineïîlî' to
:the A‘product 'tractiona'tor il!!! «wherein `vthe cracked
'products :are afractional‘ly‘iconîd'ensìed ‘to segregate.
the :insufliciently .criacked' 'constituents ’as con
ydensate. The shear/y condensate’fformed ‘in fthe
.bottom section fof fthe íijfra'cti'onating 4'tower' fil-fis
Withdrawn» ttherefromwthrough "line M 1and may
rbe removed :from the system-‘or 'it ’may ‘be lcoin
?bined witntreshiiieed through dine M vand pump
:d5 `for funthercraohing fitreatment.
lmateri al
may :contain "..traces .of îthe ¿catalyst ¿employed "in
the-cracking 'operation ‘which are not completely
erably >in the :form .of =a ‘vertical tower through '
removed in fthe separating iequipment. îBy lre
which the dispersion îisftorced to ‘pass in 'an iup
cycling this .fractionto .the cracking equipment,
ward Ydirection ¿against the tforce io’f gravity. 'The
.the catalyst contained therein may ‘be 'returned
lower 4portion ïof’the cracking :chamber T33 may fbe ,50 ltoitheprorcess. @ne orîmore condensates formed
provided 'with va .perforated plate F34 ’below which
.in thefractionating ‘tower '14 may lbe ycoîlll‘ec’tedïin
‘is ,a portion of reduced diameter.. ".I’he >ye’lo'city
>'trap-'out itra'ysïfllfß and '41V :and vremoved ffroni ‘the ‘
.ofl fthe ‘oil'stream Lpa‘ssing upwardly through ‘the
system- through-lines I"48 :and £9, frespectively.` Í-For l
cracking chamber .'33 ils preferably 4controlled >‘so
.exampleïa‘DieseL heating or fumac'eloi-l-ïmay be
that .the catalyst .contained ‘in the stream y-o‘f 'o'il 55 collected in: the vtop 'trap-’out Itray v'M and ‘a :gas
vap ors iten'ds to Ysettle 'from :the ìga's stream. «As vra
-oilïifra‘ctionimay îbe collected ’in «the ïtrapï-'out
"result, the idensity I*ofi-the #catalyst fwïithinïthe ’re
"actor -fis'm-aterially greater ‘thanv 4is the density lin
` '.The'orackedyapors ‘remainingïuncondensed in v
thefstreamof'oil in *the lfeed line 32"1e'ad»irïi‘g there
thezproduct ~frïactichater ’1"4 and containing the
to; The ydensity :in 'the reactor, ror- examplefm‘ay 60 4.bulk 'of l'the gasoline 'constituents 4ïiîorm'ed during
traydß;
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'-
‘
i
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f
rrange ‘from 5to 20 pounds per v’cubic-'foot "in cases
‘the
ioperaëtion pass `overhead Tt'hrough »
.fof activated clays, ‘Whereas ‘the V.density ‘of the
.linegz‘oïl ‘lto .-'a'íproduct condenser ISZ 'inifwh‘iclí ìthe
stream ¿passing tto "the frleac't‘or ‘may be ‘from î1 ‘to
Agasp'‘line .constituents are ‘liqueñed
10 pounds ‘per cubic foot. TI‘h-'e‘ye'locîtyy o'ïf the-oil
:from the :ic
'ensei' i532 ’pass fto »1a «receiver f5‘3'îin
vapors vpassing through the 'reactor fmayîb‘e "from
which ftlïe .f iquid »fîorrned 'in ‘the condenser 52
1 :foot to f5 feet -per lsecond »and `the Ytime of--re'si
segregates ifi-‘om normally gaseousïconstituents
dence -of oil >`vapors ‘Within `the reactor lrrrayîbe
’formed during ‘the cracking mloeratioïfi.> The
.from ~5 >to 50 -seconds. 'The temperature `.Within
liquid distillate separated’in 'i'fhefprcduct'receiver
the cracking zone >may »be controlled lWithin fa
¿513 `may ‘be kW"tl-i'draxyn "therefrom ithroug‘h fline 54
'substantial range, such v‘as ifrom 850° F. yto‘llOOiF. 70 ¿and the norm-ally gaseous'constituents 'may jbe ’
Withdrawn 'through .line £55 andfpassedîïto a ’suit
and
Higher
~ preferably
«temperatures
between
normally
:900° give
F. fandxl'OOïO"
.lessàcoke ifor
`
y
'Products
»uable‘iabsorptionL-or :recorre-ry' .equipment -i’orzfre
.a given conversion but :require morecazta'lystzatia
nfgiven .regeneration »temperature îto -slmplyithe
.heat-
_~
1
~
f
i
1
‘
,
moying `normally @liquid constituents'. :entiïfa'ined`
A"therei'ncß
"
-
'
“
-V
"
’
- . Returning tofnolumn' A3?! :receiying spent catalyst
' 2,406,555
'
L
. 8
t
'"st'ream f of.; catalyst and îregenerating. .1 gas. . `'I’h‘e
` :separatedÍfromtheccracked products insepara
annular spacg below the perforated plate will then
.form a. distributing zonefor the catalystfgas sus
. ' downwardly through column'B'I through a control
1 chamberl 58 in which the- catalyst-is regenerated
pension passing onto the main bodycf the -re
’generating chamber; VItiis sometimes, desirable
to introduce thefincoming stream ata‘plurality
of points around the- annular space to improve
ï Y'byî’removing combustible deposits iormed- during -
distribution.
î «the cracking process.
q f As previously
¿valve- 5,6 intoxa stream of oxidizing gas passing `
` through line-.51 and is carried by means ofthe "Gi
1 gas into the bottom portion. ofpa vregenerating `
'
' '
The velocity, ofthe -oxidizing .gas -passing
i ,- /
wset forth, it is sometimesî’of ad
10 vantage to transferheat from hot regenerated .
-cataly'st'tothe fresh oil feed in indirect heat ex
'through the regenerating chamber: 58 is prefer
changers 20 and 22,7'althoughthis step .may‘be -
ably adjusted to permitthe Vcatalyst particles to `
omitted in manycases, as laterdescribed. :To
ji'orm into a relatively densebed of kcatalyst .within
i the. regenerating chamber through which the re
this end hot regenerated catalyst vcollected in-_the
:central hopper 65 of regenerating chamber58 may
generatingA gas ïmust pass.- By'regulating the
be Withdrawn through tubes 69 and 16 and dis
` velocity >of the regenerating gas passing through
charged into a ’stream of >regenerating' gas ‘such
the regenerating chamber within certain limits, '
' -as air or inertgas-introduced through linesfll
the catalyst bed or mass within the regenerating
and '12, respectively,'which--carries'the hot -acat- '
l --chamber may be made to‘assume the appearance .
Í vof a violently boiling liquid so that the` -catalyst> [20 alyst throughv lines 13- and 14 into heat exchangers
2l) and -22 where it passes in’indirect heat ex-V
Í --particles are continuously and thoroughly- mixed.
' changev with fresh-.feed as previously‘described.
` -As la result, a `substantially uniform temperature .
The l.suspension oi- _hotL regenerating gasr after
passing through heat exchangers ‘20 and 22is
may be maintained throughoutthe full depth of '
3 »the catalyst mass and localized overheating can
returned » to the regenerating-@chamber through
’ be avoided. The velocity of the regenerating gas
lines 80 and '15.below'the'perforated .plate 68'.' ' - The invention, as previously described, involves
. -¿passing through the `regen-erator may beni thel
Í -order of from 1/2 to 10 feet per‘second, depending
the step’of preheating the oil by indirect Contact Y
upon the size cf the catalyst particles, »density and
with hot catalyst and then contacting with hot
other factors. For example, when yemploying
activated clays having a particle size between 30 catalyst :to complete the heating. ‘While 4this
method of operating has _deñnite advantages. in
` »200 and 400 standard mesh, the velocity of the
many cases, the invention also-contemplates the
regenerating gas passing through the regenerator
1 .should be between 1 and 5 Vieet> per> second to ç -omission of »the preheating step -'by indirect heat
exchange in catalyst‘heat exchangers 20 and’22.
î .obtain the above-mentioned results.
~ ~
.
j, ‘I'he `>,spent - regenerating 1 gas
after
When operating in'thismanner, heat;` exchangers
passing;`
26 and22 Ámay be omitted ora part or all of the
I :through the regenerator 58 is‘removed overhead
feed oil after passing through heatA exchanger
r--through line 59 andv is passed to'a separator 6l]
.in which catalyst powder `entrained inthe gas is
separated from the regenerating-gases. The cat
Í' valyst.powder-collected»in the separator 60 is re-ï
I8 may be by-passed around the heat exchangers
29 and 22 through line 16.
;
"' i*
tus wherein the tota1 heat requirements 'for the
, - moved through line 6| and returned to the regen
cracking operation arevsupplied by direct injec
.erator- 5B~ The regenerating gas after 'passing
Vthrough the separator 60 passes through line'62ï
to thev heat exchanger. I8 through which it may
pass-inïindirect lheat exchange relation-with thev
` `fresh feed, as previously described.
‘» - »
Fig. II illustrates afsimpliíied Vform-of'I appara
tion- of hot catalyst removed'fromfthe regenerat
.ingzone into the oil stream.
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- `
. Y - Referring to Fig'. II, for-purposes of
simplicity'
and brevity parts corresponding to those show-n ~
The regen-`
in Fig.V I have been -identiiied by prime numbers.
erating gasY isV removedfrom the heat exchanger
- NfIn Fig'. II,-the oilV to, be charged, which may be
ya 'topped-crude 0r any type of -feed stock men
I 8 through line 63 and may bepassed to addi
‘ ç_tional separating equipment, such agan electrical
V,precipitator -(not . shown) for removing finali 50 tioned hereinbef'ore, >is vintroduced intothe sys'-y
tem at :substantially vatmospheric vtemperature
traces of catalyst powder.` ThisV regenerating gas
`
Y Hl".>
> through - line*
may also lbe passedto a' waste heat boiler or other
wheat, recovery `equipment "(not shown) . ï
' `
'
5‘ Referring again to the regenerator v58, the bot
-tom-section'of the chamber is- provided with aver-1. '
- tical, circular partition wall spacedtfrom' the outer
wall ofthe chamber to form a central comparta
- l mentor hopper 65 for collecting regenerated cat- ‘f
l v alyst forreturn ¿to the 'cracking Zone. Steam orv
1 other inert stripping‘gas may be introducedîinto`
the bottom of the hopper 65 through line 65 to
` ~ >remove regenerating gas from the catalyst before
f. returning the catalyst to the cracking process and
-to maintain-»the catalyst in a fluidized condition.
-. The bottom of the center hopper or'compartment>
1 65 is‘in open'communication with catalyst tube 30>
_which-¿in turn-discharges into the oil feed line
through a control valve61.
'
~
- y The stream of regenerating-gas’and spentcat
y .l V.alyst from the cracking process passing'th'rough -
-`line 51 is introduced into the regenerating cham-`
~ber~58 in the annular space between the circular
The oil; with or without being
first preheated bypassing-:in heatl exchangeV with
. products undergoing fractionation Yinl -heat > ex
Ul -change »coils v`|3’- and-I6’ isi transferred through vline ll'v vinto whichjthe-hotv solid material is' in- . .
, troducedthrough „conduit 60.” provided Vwithj-a
«control» va-lve 51.’. vThe"result'ii‘rgf'mixture of .-oil
Y and solids-then passes through' conduit 32”'to- the
reaction chamber 33,' of-construction-similar >to
reaction chamber 33 shownin Fig.'r I. -"Theflovv
. of the mixture through the-reaction chamberand
subsequent separating and. fractionatinggequip
>ment» is the same asfthat illustrated in Fig_i~I.
In this'case, the~amount of hot catalyst 'intro
`>duced into the relatively -cool oil stream'passing
:through transfer line'l'ï' is-sufñcient to heat the
:,oil ‘to thev desired~ cracking temperature'ïan'dfto
“ supply the necessary heatfor'the cracking proc
D. ess. 'Expressed' in vanother/Way, the amount of
solid' material îsc introduced is controlled to' ob
»."tain thedesired heating.-V Theactu'al‘- amount of
portion Gland the outer wall of fthe regenerating ' :fsolid’ material- may be‘of the order of from y10
chamber. An annular perforated plate'68-may -"partei-of. solid material per part"'of‘oilvup'toi-äl)
or more parts of solidmaterial per part ofi-oil.
be,;provided above-the.' inlet Lfor. the. incoming i
2.540.655.55
9..
For example, when cracking an East Texas re.
duced crude at4 a. temperature, ofr about. 9509 F.
1~0y
such cases. a. portion of» the.A oil4 afterl circulating.
through. the heat,v exchangers 21). and. 22. may. be.~
and» regenerating the solid material ata tem
passed through line 'Il land. pump-1.8. te». an. addi».
perature between 1150° F. Yand 1200?’ E., the
tional. heat.. exchanger 1.9,. which may be inthe
amount. of solid material introduced into the oil 5. form of a waste heat boiler.
"
, '
»
stream will beof` the» order of from 15 to¿20` parts
@solid-per part of> oil..
u
.
`
A
~
> The. oil.4 after passing, through; thef heat. ex
changer lâY i'sr transferred; through line. 8_.|'. to.. line.
_
. By comparing the amountof equipment shown.
lì andr is4 returned. to. the inlet side of.; heat.. ex-.. »
in Fig. n with vthat iuustratedgin Fig. I.. it will>
be evident4 that4 a- »material saving in the equip
changers 2ll~andi2.2..
10
mentcost may be realized. by operating the. proc.
ess in such manner that the. total` heat, require-l
y
inline. 32». is. developed.. accordingE to the/pre
ferred. embodiment. ofi the invention., by.v con-.
structing the. catalyst.conduitälllofvv such height.
that. the. combined height of the catalyst within
mentsfor the operation are supplied by direct in-l
J'ection4 of. hot catalyst. removed from the regen
erating; zone> into theA oil- stream. For example,
the. cost of thepreliminar-y heating’íurnacos and..
the. regenerat'or. and. in: thev conduit. 30.> sufli.-Y
cient to. build up. hydrostatic. pressure. somewhat
in excess` of the. pressureon the oil; vapors atthe.
the. catalyst heatÍ exchangersl can be;` avoided byv
operating as illustrated in Fig. II.
t
The pressure. necessary. totransfer the catalyst
from the regenerating chamber to the oil stream.
,`
Whenl supplying iallof the h'eat. from regen
eration to the oilby direct injection of hot cat
alyst. into» the oil feed, a 4greater’amount of
point. of entry of I the~.'cata1yst. therein. Like-.
wise> the pressure-necessary to. transfer the.- cat.- -
aly’st into.- ther regenerating> gas.` stream in. line.
51. may.V be. developedv by constructing the. feed,
catalyst mustbe added. tothe oi-l>` than is the case '
when. ai part of the heat is- supplied by indirect .
conduit of aheightor elevationsufâcient to. bui-1d,
heatexchange in heat exchangers 20.»and ‘22. Ex
up a hydrostatic pressure somewhat. inv excess: of.
pressed, in» another way,` when operating without 25 the. pressure. on` the` regenerating gasA4 atthe point.
the h'eat exchangers 2‘0 and 2-2» substantially all`
of thev heat liberated during. regeneration, except
that. taken out byA regenerating` gas, mustobe ab
sorbed by the catalyst passing tothe feed oil;
Consequently, when operating in thismanner the 30
amount ofA hot. catalyst added to the oil must bev
> such that the amount. of catalyst employed. in
proportion to the amount of coke formed` in
the; cracking zone issuiìûcientto absorb substan
tially all the. heat liberated during regeneration.y
` In.v some cases the amount. of. catalyst neces
sary to. supply the heat requirements for the
cracking'` processl mayresult-in excessive` catalyst
lossegandcause. excessive cracking. resulting in
of entry ofthe'spent catalyst.v therein... This-will.
insure proper ñow of. regenerating gas, and-oil.~
and prevent. by-.passing of. oilinto. they regenerat
ing` zone. and vice. versa. In. order. to. transmit
the pressure` through the. standpipes or catalyst
feed conduits, 30v andv 3.1.»„ the.` catalyst. should- bef
maintained inafreely ñovving state therein.l In
some cases. anfluidizing, gasmay be introducedA at>
one or more spaced. points. along the conduitsto
35 maintain the catalysty in, fluidized condition. . It
may also be. desirable.> to. introduce. aV fluidizing
gas at. all.' points
the system. where. the,4 cat
alyst. is. segregated . fromthe. gas. stream.k
Tofavoid. reducing and building4 up> pressures.
the formation? of undesirable amounts. of low 40 010.I the. C2LÈ3J5¢`~SI2v passing back andl forthffrom thev
grade products,.lsuch as gas and. coke.. In.Y such
regenerating, chamber. to. the.. cracking chamber,
cases a part of the catalyst may be` replaced by
it iS of advantage. to. operate, bothithe. cracking
relatively inert heat absorbent materials such as`
andíthe. regeneration processi at. substantially.' the.
pumice, fuller’s' earth, bauxite, diatomaceous.
earth, and-sand whichl have little if any catalytic
inñuence on the reaction. The amount of such
inert solids may range from 0 to 90% of the total
solids circulated, depending upon a number of
factors, such as the nature of feed stock, amount
of coke formed, activity of the catalyst, tempera
ture of cracking and of regeneration, rate of
ycirculation and other factors. For example,
when cracking an East Texas reduced crude at
a temperature of 980° F. with acid-treated clay
wherein about 5.5% of the'oil is converted to
carbon which is retained on the solids, approxi
mately 45 parts of solids heated to 1050° F. by
regeneration will be required to preheat the oil
from room temperature to final cracking tem- '
perature and for supplying the necessary heat
for cracking. In such a case it will be desirable
to replace a part of the catalyst with less ex
same pressure levelïexcept for the pressure drop,
inherent »inthe iiow,..'and.it.isfa1so of advantage.
tomaintain the pressure drop through the sys
tem at a minimum so as to reduce the height of
tubes 3i and 3i) employed for developing the
required'pressure. The passageof the cracked
vapors and regenerating gas through the crack- -
ing and regenerating Zones at a low Velocity as
' previously described, tends to reduce the pressure
drop, since the pressure drop on a moving gas
stream increases as the square of the velocity.
It will be understood that the height of the
:feed conduits Sü and 3l does not depend on total
pressure on the system but the pressure drop
through the system and the pressure diiîerential
between the cracking and regenerating zones so
that any desired total pressure may be main
tained in the circuit.
.
In some cases the amount of coke formed dur
pensive inert material. It will be understood,
ing the cracking operation may be insuiiîcient to
however, that by regenerating at a higher tem
generate the required heat during regeneration
perature or by employing feeds which produce 65 to preheat, vaporize and carry out the cracking
less coke under a given set of conditions the
process. In such cases, additional heat may be
amount of solids necessary. to supply the> heat
supplied to the regenerator either by external
can be materially reduced. As a further exam
ple, when regenerating at 1150° F. rather than
heating or by adding a combustible yfuel into the
stream of regenerating gas. ' However, in most in
1050° F. the amount of solids to supply the re
stances the amount of coke formed during the
quired heat may be reduced from 45 parts to 70 cracking treatment will be suiiicient for heating v
about 20 parts, other conditions being the same.
the oil.
In some cases, the amount of heat liberated
The present invention also contemplates `ab
during the regeneration may be more than suffi
sorbing the excess heat formed during regenera
cient to carry out the cracking operation. In
tion by admixing With the catalyst aV relatively
12Y
it
temperature, the amount and temperature'v of theî
catalyst so introduced being Vsuiiifcient to heat said
,inert inaterial capable of absorbing' substantial
quantities of heat liberated during the cracking'
process; ""ThisY -inert adsorbentA materia1 can be
utilized for carrying lheat from the regenerator>
58 to the cracking'equipment.' '
"
' ‘
' '
oil above VStill" F. and'completely absorb the uri.
vaporizable '- constituents - contained
"
Y Having described the preferred embodiment of
the'invention, it will beï understood that "it em
braces such >other variations'and modifications as
come Within the spirit and scope thereof.l 'n
» ' What is desired to be protected by Letters Pat
ent" isz"
'
therein - Vt0
ï thereby form a relatively dry?suspension Vof` òil
vapors and catalyst;niaintainingthe oil vaporsï
n in contact with the catalyst 'within said cracking*
zone for a periodsuiîñcientto¿crack at-'least30%A
„ thereof into motor- fuel constituents, conti-nvufously'~A
separating a stream of finely divided catalyst'con-`
taining solid combustible deposits from th’e‘oilva-j'V
pors, thereafter fractionating" the oil vapors to
segregate a motor fuel fraction therefromfeòn-L
‘
\ " ILïInv a process of cat'alytically converting resid--A
ual foils 1 containing constituents unvaporizable
tinuously passing a stream of saidjcatalyst sep»
Without substantial decomposition into motor fuel
wherein the oil is'oracked 1in the >presence of aV
arated from said oil'vapors -into a regenerating
passinga stream of oxidizing gasßupwardly
solid adsorbent catalyst injsubdividedgform and ‘ zone,
through 4said rzone at avelocity limited'toform a
the lcatalystfr_egenerated Yat V_a temperature higher
than the cracking temperature; the method which Í' dense, turbulent bed of catalytic material and:
oxidizing gas in the bottom'sectionoffsaid regen
comprises passing the residual oil to be cracked
erating "zone,y burning combustible deposits from
in'i?i'direct> heat exchange relation With'regener
the ñnely divided catalyst Within said‘regenerat
ated catalyst to‘ thereby preheat said oil and cool
v
Vingzone
to thereby heatsaid catalyst to a tem-_
saidrcataly'st, returning said cooled vregenerated
perature "above the- temperature maintained in
`catalyst to the regenerating zone, mixing' saidoill
said cracking zone but below the deactivation
ïwith regenerated"cata1yst1vvhile saidcatalyst is -
‘at substantially ïthe regenerating temperature,
25
‘adding sufiic'ient-> catalyst to said oiltosupply al1
Y lof then/additional 'heat necessary for cracking~ said
' Io'il and> completely adsorb al1 oil constituents re-j
temperature of said catalyst, >the density'and tur->
bulence“ of the catalyticA material Within said re
generating zone being suñìcient to maintain a: ~
substantially iuniform temperature throughout'
`maining unvaporized at the mixing temperature,
they regenerating zone, continuously withdrawingA `
thereof,VV separating the cracked products from
regenerating temperature.
ïpassingithe resulting mixture through a crack-' 30 a stream of regenerated catalyst from the regen
erating zone and continuously returning said cat
ling zone, maintaining said oil vapors Within said
alyst to said oil stream while at substantially its '
cracking zone to obtain the desired cracking
the catalyst and -fractionating the cracked prod
îuots `toy segregate the> desired fraction therefrom.
` - _2. 5A process for the catalytic cracking of heavy
residualoils containing ar substantial portion of
constituents unvaporizable Without decomposi
1tion tofform lower boiling hydrocarbons inthe
`motor-fuelV boiling range Whichcomprises passing
a stream of said residual oil through a cracking
l zonel introducing a stream of'hot regenerated cat
1 alyst While said catalyst is at substantially regen
\ erating temperature 'into said stream of oil while
l said oil vis at a temperature‘below active cracking 45
1
I
^
3f In the process defmedby claim 2, the further
improvement in the method of circulating the
catalytic material'through said cracking and re
generating zones which -comprises maintaining a
vertical column `of said catalyst being introduced(
into said oil stream of aheightsuiiîcient togen-v
erate a pressure at least equal to the pressure 'on
the oilstream at the Apoint* of introduction rof said
catalyst therein and >maintaining the- catalyst '
within said column in a free flowing i'luidized- n
state.
'1
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HOMER Z.
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