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Патент USA US2408943

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59 3945@
Filed July 3.7„ 1944
2,408,943 _ `
Patented Oct. 8, 1946
coNvnesIoN or HYDnooAReoNs
Lev A. Melder, Chicago, Ill., assigner to Uni-versal Gil Products Company, Chicago, Ill., a
corporation of Delaware
Application July 17, 1944, Serial No. 545,264
5 claims. (Cl. 196-52)
This invention relates to an improved method
carries occluded oxygen and other oxidizing con
for the conversion of hydrocarbons, and -more
stituents which arc advantageously removed
particularly to an improved method of operat
before the catalyst enters the conversion Zone.
ing catalytic conversion processes in which the
In the present invention this removal is accom'
catalyst is continuously contacted with the hydro 5 plished by stripping the catalyst with lean reñnery
carbons to be converted and then with the regen~
gases or tail Agas from the process, preferably
erating gases.
those consisting of one and two carbon atoms.
More speciiically, this invention is concerned
The lean reñnery or tail gases may be byproducts
with a method of stripping adsorbed hydrocarbons
from the instant process or they may be reaction
or regeneration products from the catalystbefore 1o products from extraneous processes.
the latter is passed into the next contacting zone
The conventional method of stripping the cata
lyst leaving the conversion and regeneration Zone .
in the process.
One object of the invention is to reduce the
is by means of steam or other inert gases, the
quantity of air necessary for regenerating the
steam and stripped materials then commonly
Another object of the invention is to reduce the
lcading on subsequent fractionating equipment.
l5 being introduced to the subsequent fractionating
equipment. There are several disadvantages in
herent to this type of operation, for example, it
Another object of the invention is to reduce
has been found that steam when contacted with
if not eliminate entirely the danger of afterburncatalyst at high temperatures causes a rapid loss
ing occurring in the regenerator or regenerator 20 of the catalyst activity. Also when the stripped
exit duct and succeeding equipment.4
material and steam are handled in the fraction
Another object of the invention is to reduce
ating equipment it adds considerably to the load
the quantity of heat generated in the regeneraing thereon.
tion zone and thus eliminate or reduce the neces»
In one specific embodiment the present inven
sary means for dissipating this heat.
25 tion is concerned with a process for the conver
Brieñy the invention comprises stripping and
sion of hydrocarbons wherein iìnely divided
evolatilizing the contaminated catalyst withcatalyst particles are contacted in a conversion
drawn from the reactor with hot exit gases from
zone with hydrocarbons at conversion condi
the regenerator and stripping the regenerated
tions, the contaminated catalyst continuously
catalyst withdrawn from the regenerator with 30 withdrawn and contacted in a regeneration Zone
tail gas from the reñnery. The hot gases from
with oxygen-containing gases to remove the con
the regenerator will remove vaporizable adsorbed
materials from the Catalyst and dECOIhpOSe by
taminant by combustion and the regenerated
catalyst continuously withdrawn and returned to
destructive distillation the remaining deposit on
the conversion zone with the improvement which
the catalyst t0 a Coke 0f Substantially uniform 35 comprises stripping said contaminated catalyst
COmDOSitiOrl 10W in hYdTOC?ll‘bOIl COII’GSHÈ Which
before it enters the regenerating zone with spent
may be burned With a beitel’ COIllJYOì 0f the C0
regenerating gas and stripping the regenerated
110 CO2 Ta’ßîO in the Tegenel'atoï‘ exit gas than the
catalyst before it enters the conversion Zone with
normally high volatile matter ordinarily deposited
lean refinery gases.
0n the C_atalyst‘ BY Controlling the CO to CO2 40 The introduction of spent regenerated gases
Í'atio a hlgher percentage of CO' may be prodflced
into the stripper is preferably made without
and Conseguently reduce the quantity of neat
intermediate cooling of the gases to assist the car
generated .m the regenerator.' . Another advantage
bonizing and stripping operations, since in this
of me umform Coke deposltlon-and absence. of
manner they are carried out at relatively higher
volatile matter on the catalyst 1s the reduct1on 45
r u
bt ined wth
in the quantity of air necessary for regeneration
tempera“ ures „ al? are no ma y o a.
because there is a smaller amount of material
extraneous stripping agents such as inert gas,
to be removed from the catalyst by combustion.
Steam’ etc-
The exit gas from the Stripping and @cking Zone
Although th'e present invention 1s particularly
for the unregenerated catalyst, because of its 50 adapted t0 the catalytic cracking of .hydrocarbon
hydrocarbon gas and vapor and CO content, can
OHS it may also adVfmtageOuSly be employed 1n
provide a useful fuel for a variety of the fuel con-
suming units of the process or of the auxiliary
other prOCeSSeS Such aS dehydrOgel’lâfßlOn, hydl‘û
forming, aromatization, and the like.
The present invention may be _applied to the
The catalyst leaving the regenerator ordinarily 55 so-Called “ñuidized” type of process or it may be
applied to the so-called “moving bed” type of
In order to further illustrate the features and
advantages of the present invention, reference
is made to the accompanying diagrammatic draw
ing and the following description thereof in con
The stripping gas and stripped material from
stripping and coking zone I4 are directed by
means of line 2| into catalyst separator 22 wherein
the entrained catalyst particles are separated from
the gases. The gases from separator 22 may be
directed through line 23 controlled by valve 24
nection with a catalytic cracking process using
into the plant fuel system after cooling or used
the iluidized type of operation:
hot or cold separately as a relatively low B. t. u.
Referring to the drawing, I denotes the reactor
and 2 the regenerator. The reactants are sup
plied to reactor I by means of line 3 controlled
by Valve 4 and pickup regenerated catalyst from
line 5 controlled by valve 6. The combined stream
of reactants and catalyst is then directed into the
lower end of reactor I at such a rate that a dense
phase of turbulent catalyst and reactants is
formed in the lower portion of the reactor, the>
upper limit of this phase being indicated by bro
ken line 1. The catalyst employed in this process
may be any conventional cracking catalyst in
finely divided form, the exact particle size being
dependent upon the velocity of the upward flow
ing vapors in the reactor. In general, the particle
size of the catalyst employed in a ñuidîzed type of
fuel gas. _The separated catalyst is withdrawn
from separator 22 by means of line 25 and is
commingled ywith the withdrawn catalyst in line
'I‘he oxidizing gas and commingled catalyst pass
through line I9 into regenerator 2. In regener
ator 2 the upward velocity of the gas is suiilcient
to form a relatively dense catalyst-gas phase in
the lower portion thereof and a relatively light
.catalyst-gas phase in the upper portion thereof.
The interface between these two phases is indi
cated by broken line 26. The eftluent gases leave
the light phase portion of the regenerator and
pass through separator 21 wherein entrained cat
alyst particles are separated from the effluent
gases. The separated catalyst particles are directed by means of conduit 28 into the dense phase
process is smaller than that which would be em
of the regenerator and the effluent gases leave the
ployed in a moving bed process. The latter type
separator by means of line 29 controlled by valve
of process ordinarily employs catalyst in finely
39. The temperature in the regenerator will nor
divided form having a particle size of from about
mally be within the range of 950 to 1200° F.
11g” to %" in average diameter.`
The regenerated catalyst carrying occluded oxi
The temperature normally employed in the re 30
dizing components is withdrawn from the regen
actor for the cracking of hydrocarbon oils is in
erator through line 3I controlled by valve 32 and
the range of about 750 to 1000° F. with pressures
directed into stripper 33. In stripper 33 the cata
of substantially atmospheric to superatmospheric.
lyst is contacted with an upward flowing stream
Above the interface indicated by line ‘I is a rela
tively light catalyst-vapor phase from which the . of light refinery gas, preferably Ci and C2 hydro
carbons introduced through line 34 controlled
vapors carrying some entrained catalyst dis
by valve 35 which strip the catalyst of the oxidiz
charge from the reactor through catalyst sep
ing components and are removed from the strip
arator 8. Entrained catalyst is separated from
the etlluent vapor stream and returned to the
dense phase in the reactor by means of conduit 9.
The eflluent stream of gases leaves the separator
through line I0 controlled by valve II to be di
rected to subsequent fractionation and recovery
per by means of line 36. The stripping gases and
stripped material carrying entrained catalyst fines
are directed into separator 31 wherein said fines
are removed from the gaseous stream and the lat
ter by means of line 38 controlled by valve 39 is
directed after cooling to the plant fuel system, or
vDuring the conversion of hydrocarbons, the 45 commingled with the eñluent gas from separator
22, or used separately as a relatively low B. t. u.
catalyst becomes contaminated with carbona
fuel. The separated catalyst is removed from
ceous and hydrocarbonaceous materials which
separator 31' by means of line 4|] and is com
eventually would decrease the activity of the
mingled with the regenerated catalyst passing
catalyst below that at which the conversion would
eñiciently take place. It is, therefore, necessary 50 through line 5.
In order to aerate the catalyst streams passing
to withdraw catalyst from the reactor as it be
through lines 5 and I1 suitable aerating gases may
comes spent and this is accomplished by means
be introduced through lines 4I and 42, respec
of line I2 controlled by valve I3. The contam
tively, controlled by valves 43 and 44. The ma
inated catalyst is directed into stripping and
coking zone I4, which may be of smaller size as 55 terials introduced through lines 4I and 42 may be
the same as those introduced to the respective
shown, the same size or larger than vessels I or
stripping zones 33 and I4.
2 depending on the extent of devolatilization and
When operating a fluidized type of cracking
stripping of the catalyst required, wherein it is
system according to the present invention, the air
contacted with an upward moving stream of hot
exit gases from the regenerator which are intro 60 supplied to the regenerating zone may be reduced
as much as 30% as compared to the conventional
duced through line I5 controlled by valve I6. The
methods of operation. The heat which must be
catalyst in stripping and coking zone I4 is main
dissipated from the regenerator and adjacent
tained at temperatures preferably above 900° F.
equipment is proportionally reduced and the usa.
for a time sufñcient to coke the-vaporizable hydro
carbons and strip the volatile matter from the 65 ble hydrocarbons and CO recovered in the strip
pers represent potential fuel which may be di
catalyst. The catalyst is then removed by means
verted to other uses in the plant.
of line I'I controlled by valve I8 and commingled
in line I9 with oxidizing gas controlled by valve
I claim as my invention:
20. In some instances when the regenerator exit
1. In a process for the catalytic conversion of
gas does not contain suilicient heat for the coking 70 hydrocarbons wherein ñnely divided catalyst par
ticles are contacted in a reaction zone with hy
step it may be passed through a heater before
drocarbons at conversion conditions, the resultant
being introduced to stripping and coking zone I4,
or oxygen containing gas may be added to the
contaminated catalyst continuously Withdrawn
spent gas from the regenerator to partially burn'
and contacted in a regeneration zone with oxy
the volatile matter evolved in this zone.
75 gen-containing gas to remove 'the contaminant
by combustion and the regenerated catalyst con
tinuously withdrawn and returned to the reaction
zone, the improvement which comprises passing
erated catalyst particles to the conversion zone.
said contaminated catalyst downwardly prior to
prises hot combustion gases resulting from said
its regeneration through a coking zone in counter
burning step.
current contact with upwardly flowing hot spent
regenerating gas, the amount and temperature
4. In the conversion of'hydrocarbons in con
tact with solid catalyst particles in a reaction
zone wherein the catalyst is contaminated with
of said gas and the time of contact of the cata
3. The method as deñned in claim 2 further
characterized in that said stripping gas com
lyst therewith being sufficient to reduce to low
hydrocarbonaceous matter, thus contaminated
volatile coke and vapors the occluded and ab 10 catalyst particles are removed from said reaction
sorbed liquid hydrocarbons forming a part of the
zone and regenerated by burning hydrocarbona
contamination on said catalyst, withdrawing thus
ceous matter therefrom in a, regenerating zone,
treated catalyst from the bottom of said coking
and the regenerated catalyst is returned to the
zone, removing said regenerating gas from the
reaction zone, the improvement which comprises
upper part of said coking zone and separating 15 contacting said contaminated catalyst particles
entrained catalyst therefrom, combining the sep
prior to regeneration thereof in countercurrent
arated entrained catalyst with catalyst withdrawn
iiow with a hot stripping gas in a coking zone,
from the bottom of said coking zone, and passing
the amount and temperature of said gas and the
the vcombined catalyst to said regeneration zone.
time of contact of the contaminated catalyst
2. In a process for the conversion of hydrocar
bons wherein solid catalyst particles are con
tacted in a conversion zone with hydrocarbons
20 therewith being suñicient to coke a substantial
portion of the hydrocarbonaceous content of the
contaminated catalyst, separately removing from
said coking zone the major portion of the thus
at conversion conditions, thereby contaminating
the catalyst with hydrocarbonaceous matter, the
carbonized catalyst and the stripping gas con
method which comprises removing contaminated 25 taining resultant volatile matter and entrained
catalyst particles from said zone and contacting
carbonized catalyst, introducing the withdrawn
the same in a coking Zone in countercurrent flow
with a hot stripping gas, the amount and tem
perature of said gas and the time of contact of
stripping gas into a separation zone and therein
separating said entrained carbonized catalyst,
combining the thus separated catalyst with said
the contaminated catalyst therewith being suñi 30 major portion of carbonized catalyst, introducing
cient to coke a substantial portion of the hydro
the combined catalyst to said regeneration zone,
and contacting said regenerated catalyst prior
carbonaceous content of the contaminated cata
lyst, separately removing from said coking Zone
to its return to said reaction ~zone with a strip
ping gas comprising normally gaseous hydrocar
the major portion of the thus carbonized cata
lyst and the stripping gas containing resultant 35 bons in a stripping zone to remove occluded oxi
dizing components from said regenerated cata
volatile matter and entrained carbonized cata
lyst, introducing the withdrawn stripping gas
into a separation zone and therein separating said
5. The improvement as defined in claim 4 fur
entrained carbonized catalyst, combining the thus
ther characterized in that said hot stripping gas
separated catalyst with said major portion of 40 comprises combustion gases removed from said
carbonized catalyst, burning carbonaceous depos
regeneration zone.
its from the combined carbonized catalyst to re
generate the latter, and returning thus regen
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