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3am, M, £947.’
Original Filed Sep‘i. 4, 1941
(033:: H3385 slsva) NOQHVI) °/° .LHDIBNM
Patented Jan. 14, 1947
2,414,256 '
du Bois Eastman, Scarsdale, N. Y., and Charles
Richker, Port Arthur, Tex., assignors to The
Texas Company, New York, N. Y., a corporation
of Delaware
Continuation of. application Serial No. 409,488,
September 4, 1941. This application January
24, 1945, Serial No. 574,389
2 Claims. (Cl. 196-52)
This invention relates to the catalytic conver
scale using a 1[2-inch cell; (2) employing a crack
sion of hydrocarbon oil to gasoline hydrocarbons
ing catalyst of high and sustained activity; (3)
suitable for motor fuel.
prolonging the conversion cycle time or onstream
The invention broadly contemplates a process
time to a period not less than one hour or prefer
wherein feed hydrocarbons are heated to a cata 5 ably of the order of about 8 to 20 hours or more;
lytic conversion temperature and passed, while
and (4) heating the feed oil to the conversion
substantially in the vapor phase, through an ac
temperature under conditions such that it under
tive mass of solid catalyst with a relatively high
goes substantially no change in composition prior
lineal velocity of hydrocarbon ?ow through the
to contact with the catalyst (heating under con
reaction zone so as to maintain conditions of 10 ditions such that the soaking volume factor, de
turbulent ?ow through the catalyst mass in the
termined in the manner described in the afore
reaction zone.
said Patent 2,378,292, does not exceed about 1.0
In catalytic cracking a stream of oil in sub
and is as low as possible, in the range about 0.05
stantially vaporized form and heated to a conver
and below). L i‘
sion temperature in the range about 800 to 1100° 15
The present invention has to do With the dis
F. is passed through a catalyst bed maintained at
covery that carbon deposition upon the catalyst
the conversion temperature so as to convert the
is in?uenced to a substantial extent by the condi
oil to gasoline hydrocarbons. The conversion to
tions of ?uid flow existing through the catalyst
gasoline hydrocarbons is accompanied with con
mass. These conditions which exert a critical
comitant breakdown of a portion of the feed oil 20 in?uence upon carbon deposition can be de?ned
to gas and coke or carbonaceous material, which
by means of the formula for determining the
latter is deposited upon the catalyst. As a result
modi?ed Reynolds number, reference to which
of this carbonaceous deposit the activity of the
appears in an article entitled “Pressure drop in '
catalyst, as measured by the percentage conver
packed tubes,” by Chilton and Coburn, Ind. Eng.
sion to gasoline and gas, decreases. It has been 25 Chem., August, 1931, vol. 23, No. 8, pages 913-919.
customary to operate such a process with an ex
This formula is as follows:
ceedingly short conversion cycle or onstream time
and thereafter terminate the flow of feed hydro
_ D1, UP
carbon through the catalyst bed, following which
the bed is reactivated‘ by passing therethrough a 30 where
highly heated gas containing air or oxygen to
burn off the carbon deposit and thereby restore
R is the modi?ed Reynolds number;
the activity of the catalyst. In such operations,
Dp, is diameter of catalyst particles in feet;
the operating cycle is such that the catalyst
cracking chamber is oiistream for at least twice 35 ‘ U is average velocity in feet per second of ?uid
mixture ?owing through the catalyst tube, the
the period of time that it is onstream or is actu
tube being regarded as empty;
ally being used for the conversion operation.
‘ P is average density in pounds per cubic foot of
_As disclosed in our pending application, Serial
?uid mixture ?owing through the empty tube
No. 383,900, ?led March 18, 1941, which has ma
‘ tured as Patent 2,378,292, improved results are ob
tained including greatly increased throughput
and higher efficiency of operation of the plant by:
(l) selecting a charge stock preferably relatively
free from unsaturated constituents and which is
relatively clean and of good color, namely, having 45
a carbon residue of less than 0.2% and a color
of less than 200'as measured on the Lovibond
under the operating conditions of temperature
and pressure;
Z is viscosity of‘ the ?uid mixture ?owing through
the empty tube in pounds per foot per second
under the operating conditions of temperature
and pressure.
The value Z in the foregoing equation is: deter
mined by multiplying the absolute viscosity of the
The feed oil comprised a mixed base virgin gas
oil having the following characteristics:
reaction mixture in centipoises by the factor
The viscosity of hydrocarbons at the tempera
ture of conversion may be determined by refer
A. P. I. gravity_________________ __degrees__
ence to the nomograph on page 608 of Industrial
and Engineering Chemistry, vol. 28, No. 5 (article
entitled “High temperature viscosities of liquid
A. S. T. M. distillation:
I. B. P., °F ________________________ __ 434
petroleum fractions,” by Watson, Wien and
Murphy). Using this method of viscosity deter
20% ______________________________ __ 554
mination the viscosity of the reaction mixture in 10
the usual catalytic cracking operation will be ap
proximately 0.10 centipoise where agas oil hav
ing the characteristics indicated- below is being
catalytically cracked at a temperature of about,
F. to
40% by weight
of naphtha also
> 578
. 40% _________ _.'_‘ ______ _.. _________ __
_ nNaphtha
______________________ _.;-.;. ____ _.
60%‘v ____________________________ __ 658
70%___..;_ ____________ __._________ __
wGas oil feed
Color, 1/2 inch Lovibond ________________ __
Carbon residue _______________ __per cent-.. 0.04
In?eachinstance the gas oil was passed in a
.;i.eontinuous,.stream through a coil heater under
A. P. I. gravity _______________ _.
p, _
Speci?c gravity _______________ ._ 71874.; ____ __’_'.._’ r0739.
Referring to the nomographic chart; it, ,wilhbe
found that a gas oil of th'e'foreg'o'ing~ character \
will have a viscosity of about 0.19 centistoke‘ at
950° F. while the naphtha will have a-viscosity
of about 0.09 centistoke at 950° F.
1 Viscosity ineeentistekes is eonvertedtdviseosity
v. in: aeentipeisesiby :multiplyinstm former; by: the
gfvspeuci?c gravity of thehydifocaijbon so that the
qrliigh ‘ temperature viscositics of v the gas ' oil, and
:2 naphtha in termsef centipoisesettheeonversion
temperature will be:
.19><:875’=0.1,66v ,centipoise. (for. gas ,oil)
4 7:09 >_<".,739'=:0;Q6,6 centipoise (for naphtha)
wherein it
Viscosity in centistokcs _______ _. 2.3 at 210° F-_.__ 0.65 at 100° F.
5 pounds per square inch gauge
“,eated to a temperature of 950° F.
and while, in substantially the vapor phase passed
~:,__-through acatalystbed comprising alumina, silica
ndqnzirconianhaving a composition of approxi
"mately "20%‘a'1umina, 70% silica and 5% zirconia.
,;;_.,The'_ catalyst comprised cylindrical pellets one
eighth of an inch in diameter and in length, the
mass having a free_,.space.of_ about .35%.- »
. VariationIin- ,thenature ._of..?uid > flow. through
the catalyst mass whilegnaintaining,thelsame
space velocity. may be. accomplished. ,by/ altering
, v[the depthand crossgsectional area of thecatalyst
_ bed from run to run,.or,by varying thesizefand
. shape of the catalyst.
' , In each run theoil waslconverted,to.3,0%.gaso
line bylvolume of.the_feed oil, the-gasoline .being
' characterized.v by having a. Reid; ,vapor . pressure
. On . the. basis thatv the reaction mixture come
;of 91/2 pounds» and an end boiling pointof400". F.
prises 50% gas oil and 40% naphtha by’ weight,
The onstream period extended over a. period of 4
40 hours :following. which the. catalystfwas reacti
the effective 'viscosity of; such' mixture is:
vated in .the .usual manner and again placedon
0.l66><.60=.0996 centipoise
stream, the operation being repeated, for
‘ 0.060>< .40—_-.0_264 centipoise
.1260 centipoise
" mum ofsix cycles .under each lineal velocity con
“Thefqlfegoing calculation ignores the presence
_ 10f , normally gaseous hydrocarbons in, the ,reac
. During each regeneratingcycle therate of flow
of the oxygen containing regenerating. gases .fed
, tothereactorundergoing regenerationjwas held,
tionmixture, the presence of which will reduce
a at a constant measured‘rate andithecomposition
a the effective viscosity. somewhat so. that a value
. of the .gases rentering .and leaving the. reactor
_' of, .10 centipoise maybe regarded as substantially I ,~ determined. at frequent intervals.‘ . f The . quantity
lofrcarbonaceous. material removedfrom the cata
, representative, of the viscosityhoflthe. reaction
lyst during regeneration was ,.then.~,determined,by
._ ,mixtureunder the conditions speci?ed.
, integratingtheincrease in; carbon monoxide. and
' It has been foundthatfor practical purposes
carbondioxidegcontent. of. ,thegases .overthe re
the effect of pressure,v in they range atmospheric
to about 100 poundsper square inch gauge, upon "j igenera-tinereriod. and;multiplying-births: quan
jtity' of;theregeneratine?igas fluse‘d. ,l'fl‘hese .‘deter
the viscosity may be ignored.
Thus, in accordance with the present invention, , ‘initiations were ,veri?ed by‘ .calculatingivthe, carbon
, deposition from .the._consurnption.,of. oxygerndur
it has been found advantageous to operate a
catalytic cracking processiwith conditions of ?ow
through th'epatalystbed such that the; modi?ed 60 .i ‘As. indicated on the_.drawing,. thescurzve isgrela
, Reynolds number asdeterminedbythe foregoing , .tiyfely'?atin, the range 100Yand. abovegwhile below
'-‘,formula has a‘value; in the rangeab'outf100 to
I. hisrangeit rises. rather. steeplytbward; the‘. ver
f tical. '[Thus, .the Iregion below a;.. modi?ed
Reynolds .number. of .100 the, yield‘ . voiicarbon, .9 de
posited on .the, catalyst increases ‘quite, rapidly,
This is borne out by-the graphicalrelationship
- between modi?ed Reynoldsnumberyand yield of
- carbon, per cent by weight of the feed hydro
carboni-shown in the accompanying}- drawing.
; whereas inthelreg'ion abet/e100 therate ofphange
, ‘in, carbon oleprfisitionv is relativelysmallwith .Varia
_tion in the;fluid1_?ow_through,the bed. Iniother.
words, when operating. with conditions,“ ,?ow
The curve of this drawing is plotted-on log log
-paper and the points on the curve were de
,aitér‘mined-in a series 'ofruns employing the same 10‘
(type of feedioil with the ‘same catalyst under sub
stantially similar conditions -of ‘temperature,
pressure and space velocity but, with different
' linealyelocities of hydrocarbon flow through the
*catalyst bed.
corresponding to. a.._,modi?ed.-Reyncldsrnumber
in" the range. .l00. andgabqvethe ;y.,.i.e1d;.ei. carbon
,de'pqsitedpn‘ theeetelxst greases.-.fr9m.ales>uti.55
pier/40%, by.weight2of._raw.iee<i;ei1-. . "
j J
" ‘It is advantageous to; operate ‘with'lteynqlds
75 numbers well" above ‘the critical so as to minimize
U ‘2,414,256
any e?ect of ‘pressure upon the rate of carbon
- deposition.
In the case of the‘ foregoing curve
a Reynolds number of about ‘40 would be in they
;_ critical region.
The conditions of ?ow existing through the
catalyst, mass may be in?uenced to some extent
by thei'size and shape of the catalyst particles,
lumps‘ or granules since the free space of the
catalyst mass may vary from about 35 to 45%
by volume of the reactor space occupied by the 10
catalyst mass.
"ingarpreheated and vaporized stream of heavier
hydrocarbon oil charge stock having a carbon resi
due of less than 0.2% and a color of less than
7200 on the Lovibond one-half inch scale through
a‘ contact mass or aluminaesilica-zirconia catalyst
having acompositionof approximately 20% alu
‘mina, 70% silica and 5% zirconiajmaintaining
the contact mass at a temperature of about 950°
F. and under a pressure in the range atmos
pheric to about 100 pounds per square inch gauge,
maintaining conditions of hydrocarbon ?ow
In the foregoing experiments a synthetic silica
through the mass such that R has a value in the
alumina-zirconia type catalyst was used. How
range 100 to 1000 as determined by the equation
ever, it is contemplated that other catalysts may
be employed. Various.acid-treated and metal 15
substituted clays, such as the Super-Filtrols, are
satisfactory. Likewise, the acid-treated and
metal-substituted natural or arti?cial zeolites,
such as the arti?cial zeolite known as Doucil, can
R is the modi?ed Reynolds number;
be used. Various metals can be substituted in the 20 Dp is the diameter of catalyst particles in feet;
clays or zeolites, such as uranium, molybdenum,
U is the average velocity in feet per second of
?uid mixture ?owing through the reaction
manganese, lead, zinc, zirconium, nickel and the
like. Likewise the combination of certain acid
chamber, the reaction chamber being regarded
as empty;
treated active clays of the'character of Filtrol,
together with added proportions of alumina or 25 P is the average density in pounds per cubic foot
silica or both can be employed. Alumina alone
of ?uid mixture ?owing through the reaction
may be used under certain conditions. The syn
chamber under the operating conditions of tem
thetic silica-alumina catalysts can be improved
perature and pressure;
by the addition of other constituents, such as zir
Z is the viscosity of the ?uid mixture ?owing
conium oxide or molybdenum oxide. Other cat
through the reaction chamber in pounds per
alysts which are not silica-alumina catalysts,
foot per second under the operating conditions
either synthetic or prepared from natural min
of temperature and pressure;
erals, have been found which satisfy the char
the ?ow of said stream through the
acteristics of the catalyst of the present inven—
without intervening reactivation for
tion. Examples of other suitable catalysts com
a period of at least several hours onstream, 0b
prise metallic halide compounds such as the hal
taining a, substantial naphtha yield with a car
ides of aluminum and chromium, etc. In general,
bon yield of not in excess of about 0.55% by weight
a catalyst is employed which is stable at high tem
of the feed oil, thereafter discontinuing the flow
peratures of the order of 1400 to 1600° F., as de
termined by calcining in a mufrle furnace at that 40 of the hydrocarbon charge in contact with said
catalyst, reactivating the catalyst in situ and then
temperature, and which is a measure or indica
the process.
tion of the ability of the catalyst to maintain its
2. In the catalytic cracking of a normally liq
activity under the customary temperatures of re
uid heavier hydrocarbon oil charge to convert the
activation of the order of 1100 to 1400° F., as
same to gasoline hydrocarbons involving alternate
measured by thermocouples within the catalyst 45 periods of conversion and reactivation, the meth
bed during the reactivation cycle. It is preferred
od which comprises continuously passing a pre
to employ a catalyst which is substantially free
heated and vaporized stream of heavier hydro
from alkali and alkaline earth metals.
carbon oil charge stock having a carbon residue of
Also if desired the conversion reaction may be
carried out in the presence of light gases such 50 less than 0.2% and a color of less than 200 on the
Lovibond one-half inch scale through a contact
as hydrogen and hydrogen-containing gases, in
mass of alumina-silica-zirconia catalyst having a
cluding gases produced in the reaction and which
composition of approximately 20% alumina, r10%
may be recirculated through the heating and con
silica and 5% zirconia, maintaining the contact
version zones or through the conversion zone only.
at a temperature in the range 800 to
Although the invention has particular applica 55 mass
1000” F. and under a pressure in the range at
tion in the conversion of gas oil and other high
mospheric to about 100 pounds per square inch
boiling hydrocarbons, it may be employed in ef
fecting catalytic conversion of various types of
hydrocarbons at elevated temperatures.
gauge, maintaining conditions of hydrocarbon
?ow through the mass such that R has a value
in the range 100 to 1000 as determined by the
The present application is a continuation of 60 equation
our pending application, Serial No. 409,488, ?led
September 4, 1941, for Catalytic conversion of hy
drocarbon oil.
Obviously many modi?cations and variations
of the invention as above set forth may be made 65 R is the modi?ed Reynolds number;
without departing from the spirit and scope there
D1) is the diameter of catalyst particles in feet;
of, and therefore only such limitations should
U is the average velocity in feet per second of
be imposed as are indicated by the appended
?uid mixture ?owing through the reaction
chamber, the reaction chamber being regarded
We claim:
as empty;
1. In the catalytic cracking of a normally liq
P is the average density in pounds per cubic foot
uid heavier hydrocarbon oil charge to convert
of ?uid mixture ?owing through the reaction
the same to gasoline hydrocarbons involving al
chamber under the operating conditions of tem
ternate periods of conversion and reactivation,
perature and pressure;
the method which comprises continuously pass 75 Z is the viscosity of the ?uid mixture ?owing
~i~throughwthew reactiomchamber'ain;mounds‘"per
v'r-iyie'ld of not: in :excessfof'~abouth0;55% ‘by weight
, r: :‘ofatemperature:andipressure ;
continuing théi?dw‘ Abfsaid~~stream~thrqugh»the
bf'theMfeed-‘oiL? thereafter discontinuingi-ithelr?ow
-'-~-'=ofil'the- hydrocarbon lcharge' in-v contact» with said
’ catalygt, reactivating the catalyst 'in'situ and then
'" ‘,contact mass'withoutintérvenipg' reactivation‘ for ‘*repeatmgthepmcesa
‘ ‘ a periodmi jat' 1east4severa1j hours onstre'amrob,
1;:tainipg a: substantial‘naphthao yield with a." oarbon
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