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.1. R. SCHQNBERG Erm.
2,412,649@
PROCESS FOR REGENERATION OF CRACKING CATALYSTS
Filed « Oct. 23 , 1940
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Patented Dec. 17, 1946
2,412,696 .
VUNITED STATES' PATENT oFFlc
PROCESS 'FÜR REGENERATION OF
.
CRACKING CATALYSTS
Jackson R. Schonberg, Westfield, and Donald L.
Campbell, Roselle Park, N. J., asslgnors to
Standard Oil Development Company, a corpo
ration of Delaware
Applicatlon October 23, 1940, Serial No. 362,380 r‘
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,
"’
2 claims» (ol. cs2-_242)
1
.
2
The present invention relates to improvements
advantage of this process is that it requires a
in the art of reactivating or regenerating solid
large combustion chamber to provide the neces
divided catalytic materials containing carbona
sary time of contact due to the large volume of
ceous contaminants by means of combustion of
total gases required, This _known process also
the catalyst contaminants under closely con 5 requires large and expensive equipment. to sepa
trolled conditions. 'I'he catalyst may be an acid
rate the regenerated catalyst from the gases leav-`
treated clay, silica gel, or a plural gel, such as
ing the combustion chamber.
silica-alumina gel or alumina-silica «compositions»
The main object of our invention is to regen
in powder form and its regeneration may be of
erate a fouled catalyst, suspended in a regenera
the type wherein the catalyst is' suspended in an 10 tion gas, to remove the suspension after regenera
oxygen containing gas during regeneration. The
tion of `the catalyst from the regeneration zone,
catalyst contamination may be due to its sus
and to return a portion -of the regenerated cat
pension in high boiling hydrocarbons under
alyst from said removed suspension, after cool
cracking conditions.
ing, to one or more points in said regeneration
It is, of course, well known that when an acid 15 zone in order to control the temperature of the
treated clay is contacted with a hydrocarbon oil
under suitable conditions of temperature, pres
Other and further objects of our invention will
sure, time and intimacy of contact, as for ex
appear from the following more detailed descrip
ample, where a gas oil is cracked in the presence
tion.
of an acid-treated clay, the process results in the 20
These objects may be carried out by the process
progressive deposition of carbonaceous materials <
and apparatus hereinafter fully described‘in con-upon the catalyst. These contaminants impair
junction With the accompanying drawings form
regeneration.
the activity of the catalyst and necessitate the ’
removal from the conversion operation, of the
'
‘
"
.
ing part of this Specilication.
'
‘ In the accompanying drawings, Fig. 1 shows a
catalyst after it has accumulated about l/3% to 25 combination of apparatus elements diagrammati
5% by weight of contaminants for reviviñ'cation
cally and in partial vertical section, in which cat
or regeneration and as indicated, the most satis.
factory regenerationv method is one in which the
contaminants are removed by combustion of the
latter.
alyst may be suspended in a regeneration gas. . .
conducted to a regeneration chamber, removed
from said regeneration chamber, separated from
30 the gaseous constituents and returned in part'
Our present invention Ais concerned with. the.` , after cooling to the regeneration zone to aid in
regeneration of a solid spentcatalyst by burning
- or oxidizing the contaminants under closely con
trolled conditions of time of contact of catalyst
. and regeneration gas; also of temperature, pres
controlling the temperatures therein prevailing, l
and in Fig. 2, which is a modiñcation of the proc
essl illustrated by Fig. 1, means `are provided
35 for returning the cooled regenerated catalyst to.
sure, and intimacy of mixing and handling of the ,
the regeneration zone at a plurality of spaced
catalyst, so as to prevent overheating or baking
of the catalyst, or otherwise injuring its activity.
It is generally known in the art that a‘ catalyst
such as an adsorbent clay -catalyst cannot be sub
jected for a considerable length of time to a tem
apart points.
-
Our invention will now be more specifically de- Í
scribed in its embodiment shown in accompany- ‘
40 ing Fig. 1. Referring in detail to the drawings, s
the reference character I designates a hopper
perature above 1100° F., certainly not above 1200°
containing a, powdered catalyst to be regenerated.
F., without permanently injuring the catalyst. It
This material may comprise, for example, natu
is also known that catalysts of the type indi
rally active or activated adsorbent clays or syn
cated can be regenerated without injury by using 45 thetic adsorbent materials of the same or differ
air strongly diluted with inert or non-oxidizing
ent composition._ The catalyst, we may assume, ,
gases. This can be vdone by .suspending the fouled
is contaminated with carbonaceous deposits asa
catalyst in a mixture of the air and other gases
result of contact with hydrocarbon vapors during
at a temperature just above that at ,which com
an oil cracking operation.
W
bustion proceeds with reasonable rapidity, and 50 Prior to regeneration of the catalyst materiahn
the presence of the diluting gases insures that
it may be purged to remove volatile hydrocar
the heat generated by the combustion will not
bons. There are many known' methods of purg- ,
raise the catalyst temperature and the resulting
ing or stripping the catalyst. Most of them in-l
mixture of gases above a temperature at which
volve causing the catalyst to ñow ‘countercurrent`
injury to the catalyst ensues. However, one dis 55 against a gas, such as steam heated to approxi-,5~v
2,412,696
3
mately the> temperature of the catalyst itself.
The catalyst material still at an elevated tem-.
perature, approximately that of the outlet of the
cracking reactor is continuously withdrawn from
the> hopper I by means of a feeding mechanism,
such las a star feeder 2, and discharged into a
suitable transfer mechanism, such as a screw con
veyor 3, and by means of the latter discharged
into a chamber or chest 4.l
Air or other free-oxygen-containing regener
ation gas at atmospheric ltemperature is drawn
through line 5 into blower 6, discharged to lines
1 and 8, through a suitable regulating valve in
line 8, and into said chest 'at point 9. Within
’said chest a suspension, of the catalyst in the 15
regeneration gas is formed. From chest 4 the
suspension is withdrawn through line I0, thence
'
y
t
it is withdrawn through line 2I to conveyor 22,
which may be similar to conveyor 3, above de
scribed. The conveyor l22 discharges the said
catalyst into chest 25 where it is suspended inl
compressed air supplied by blowers 6 through lines
'l and 24 and a suitable control valve in the
latter‘line, the air being discharged into the
chest at point 23. The suspension is withdrawn
through line 26 and forced through heat ex
changer 21 where it is cooled by a cooling medium
introduced through line 28 vand withdrawn
through line 29. The cooled, suspended cata
lyst is withdrawn from the heat exchanger 21
through line 3l) and mixed with the suspension
of fouled catalyst, leaving line I0, in line II as
previously stated.
.
The portion ofthe suspension in line I6 from
which it is not desired to remove catalyst for
return to the chamber is withdrawn through a
in air or other free-oxygen-containing gas in 20 regulating valve and admixed with the gas recov
ered from separator I8 and both are discharged
a manner which will be presently fully described,
into an initial cyclonel separator 32 where the bulk
and the confluent suspensions are discharged into
of the catalyst is separated from thegas. The
a, regeneration chamber I2 through means pro
catalyst so separated drops to the bottom of
vided to agitatoy the contents of said chamber.
said
cyclone separator and is discharged into con
25
This latter means may consist of an inlet mani.
duit 33 through star feeder 34 into a stripping
fold discharging through a number of pipes I3
discharged into linel I I containing a suspension
of cooled, recently regenerated catalyst suspended
chamber-35, wherein it passes downwardly in
countercurrent flow against an upflowing strip
ber, each pipe discharging through a number of
ping
gas, such. as steam CO2, flue gas, etc., intro
perforations or nozzles I4, directing iiow hori
zontally into the chamber. Similarly the sus 30 duced into the stripping chamber through line 36.
The stripping chamber 35 is preferably provided
pension may be withdrawn from the chamber
with a plurality of baflies such as inverted cone
through a like arrangement of nozzles and mani
and slanted peripheral bailles 31 to insure inti
fold pipes I5 adapted to receive and Aconduct the
mate contact between the catalyst and the strip
suspension downwardly and out of the chamber
35 -ping gas. The strippingv or purging gas serves
I2 through line I6.
to remove oxygen containing gases from the
The use of the --above mentioned pipes and
catalyst. The stripping gas introduced into the
nozzles causes the contents of the regeneration
stripping chamber 35 passes upwardly there
chamber to be thoroughly agitated, and inter
through and is discharged therefrom through line
mixed. The injected suspension of catalyst is
48 into line I6 as shown, where it admixes with
40
heated by contact with the contents of the cham
the suspension therein and is thereafter proc
ber to the temperature of combustion of the
essed with the latter.
`
catalyst contaminants which is proceeding in the
The powder, after being purged of regenerating
chamber. Therefore, the catalyst throughout its
gases in the stripping chamber 35, is collected
time of residence in the chamber is at a con
siderably higher average temperature than it 45 in the bottom thereof and may be removed there
from to conduit 38vcarrying a suitable pressure
would be >if it passed, let us say, lengthwise
seal such as a star feeder 38. The regenerated
through a long narrow chamber in which there
catalyst is preferably passed directly to a con
' was-no agitation ofthe contents and little, if any,
version unit, e. g., a cracking unit (not shown)
heat transfer from the catalyst already resident
while still at elevated temperature so that the»
:Y1 for sometime in the chamber to that portion of
heat of -regeneration can be Autilized in carrying
`-catalyst at its moment of entry. The above
extending vertically downward into the cham
Vmentioned agitation permits cooling either the
. suspension of spent catalyst or the suspension of
out the conversion treatment.
`
,
Gas from the cyclone separator 32, having th
bulk of the powdered catalyst removed there- v '
recycled recently regenerated catalyst or both to
a relatively low> temperature while- still obtaining 55 from, but still containing a substantial amount of
powdered material, is removed from the cyclone
relatively rapid combustion in the regeneration
separator 32 through line 40 leading to a sec
chamber. This cooling of the suspensions to
ond
cyclone separator 4I wherein further -powder
loW temperatures> is of advantage in reducing
is removed from the regenerating gases.~ Regen
the rate of catalyst recycling required in order
to provide suflicient cooling in the regeneration 60 erated powder separated in lthe second cyclone
separator 4I drops to .the bottom thereof and
chamber. Also with all of the catalyst in the
may be removed to line 42 and introduced into
regeneration chamber being oxidized at a rela
the top of thestripping chamber 35 wherein it
tively high temperature rather than at a tem- .
perature rising gradually from a relatively low~ is stripped of regenerating gases in the same ,
inlet temperature to a higher outlet temperature, 65 manner as the catalyst from the initial cyclone
the rate of `oxidation is increased and the size A
of the regeneration chamber required is corre- »
' separator 32. The conduit 42 is preferablypro
vided with a suitable pressure seal such as a star y
feeder 43 to prevent the stripping gases from
passing upwardly into the second cyclone sepa
A portion’of the suspension is withdrawn from
line I6 through line I1 anda suitable regulating 70 rator. The gases, after passing through the sec
ond cyclone separator 4I, are removed there
valve and discharged into cycloneseparator I8. .
.from through line 44 leading to a third cyclone
The major portion 'of the lcatalyst contained in
spondingly reduced.
separator 45 for removal of the remainder ,ofl
the said portion ofthe suspension is separated
from the regeneration gas in said separator -and ' the catalyst from the regenerating gases. ‘Cata
is removed through line I8 into hopper 2li, thence 75 lyst separated in the third cyclone separator 45 is
2,412,696 f
5
discharged into .the stripping chamber 35
through line 4I, provided with a star feeder 41.
'I'he regenerating gases, after passing through the
third cyclone separator 45, are substantially tree
of powdered catalyst.
The gases are removed
from` the .third cyclone separator 45 through line
49, _and may be rejected from the system through
The modiñcatlon shownin Fig. 2 has regard
to the form and construction of »the regenera-`
tion vessel and the means forÁ supplying regen
erated catalyst and spent catalyst to the said re
generation chamber. That is to say, the catalyst
is suspended in this modiñcation in exactly the
same manner as in the modification shown in
a pressure relief valve 50 adapted to impose the
Fig. 1, thence »thev suspended catalyst is discharged
desired back pressure on the system.
into line I0a and thereafter passed into the bot
tom of an elongated regeneration chamber |2d.
It will be understood that 'the apparatus de
scribed may be modiiled in many ways known to
those skilled in the art. For example, the means
used for conveying the catalyst from `hopper I,>
into the chest 4 may comprise a‘lock hopper sys
tem such as was shown in the prior application of
Donald L Campbell, Serial No. 311,477, filed De
cember 29, 1939, with suitable alterations to Der
mit operating‘the uppermost compartment un
der low pressure and the lowermost compartment
In the illustration shown we may consider
that the regeneration. chamber I2a contains four
zones viz. -zones 8|, 82, 83 and 84.
Hot regener
ated catalyst is withdrawn from a `hopper 90,
discharged into a screw conveyor 92, (shown only
in end View) thence into a chest 98, where it is
dispersed in air discharged into the chest through
valve line |00. The dispersion of hot regenerated
catalyst in air is then withdrawn from the chest '
under high pressure, or may consist of some other 20 98 through conduit |04, thence 4passed through a
cooler |06, Where a portion of the sensible heat
device for conveying the fouled catalyst continu
of the catalyst is removed by heat transfer to a
ously against the pressure differential. Similar
cooling medium such as water, with which it
ly, conveyors 3 andI 22 may be replaced by some
comes in indirect heat transfer relationship. The
other device for accomplishing the same purpose.
cooled catalyst is then withdrawn from the cooler
Also, the means for injecting the regenerating 25 through
conduit |08 and discharged into the
suspension` through line I I into regeneration
uppermost portion of the zone represented"
chamber I2 may be varied. For exam-ple, the sus
by the reference character 83. In `like man
pension may be injected through a Venturi mixer
ner, catalyst from hopper 90 is discharged into
into which the contents of the regeneration cham
screw conveyor I|2, thence into chest II4 where
ber are drawn for the purpose of agitation with 30 it is dispersed in air discharged into the chest
the incoming suspension, or, as another alter
through line ||6. Thereafter the catalyst is with
native, the contents of the chamber may be agi
drawn through line |I'I, discharged into a cooler
tated by means oi’ a multi-bladed ian as dis
closed in the prior application oi’ Donald L. Camp
bell, Serial No. 234,555, now U. S. Patent 2,282,453,
iiled _November l2, 1938.
|»|9, similar to cooler |06, and thence discharged ‘
through line |20 into the uppermost portion of
zone 82. Finally, the catalyst in hopper 90 is
discharged into screw conveyor |21, thence dis
Further, .the means for removing from the sus
charged into mixing chest II9 where it is dis
pension leaving the regeneration chamber, the
persed in air discharged into the chest through
portion of the catalyst which it is desired to re 40 line 6|, thence withdrawn through conduit |28, '
turn to the regeneration chamber may be varied. .
thence discharged into cooler |30, and then forced
For example, all of the suspension leaving the
chamber may be Withdrawn through a single cy
clone separator from which part of the separated
catalyst is returned to the regeneration chamber
and-part withdrawn through suitable apparatus
Ior further use in cracking. Also, other means
may be employed, such as electrical precipitators,
to remove the catalyst- from the suspension.Y
The heat exchanger 21 may Ibe a boiler water
i’eed preheater or a waste-heat boiler, or a pre
heater for the feed to the catalytic unit. `
into zone 8|.
The spent catalyst passing up- `
` wardly through the regeneration vessel is periodi
cally contacted with cooled regenerated catalyst
in the manner‘shown. The catalyst enters the
zones 8 I, 82, 83, and 84 at the minimum tempera
ture at which reasonably rapid combustion can
be obtained, say a temperature of 850° F. or there
’abouts, and leaves the several zones at the maxi
mum permissible temperature that will not cause
be varied to suit a number of conditions, such as
impairment or‘destructîon of the catalyst. The
hot catalyst undergoing regeneration is- cooled
by the cooled regeneration catalyst from the
maximum temperature to the minimum tempera
ture at which reasonable rapid combustion may
the kind and character of the catalyst, the tem
take place. Also, the amount of oxygen in line
It will, of course, be understood that the oper
ating conditions prevailing in chamber I2 should
perature which it can stand without injury, the
amount and character of the contaminants on
the catalyst, and the'- degree ~to which these are
to be removed to make the catalyst suitable for
further use, and other factors. However, gener
ally speaking we may say that the following con
ditions in the chamber give good results:
Pressure from 1 to 30 atmospheres absolute.
Temperature of mixed suspensions entering re
generation or combustion vessel from atmos
pheric to 950° F.
Temperature of suspension leaving combustion
'
vessel from 1000 to 1l00° F.
I0a is so regulated as to be substantially all con
sumed at the point where further quantities of
oxygen is added together with cooled catalyst
through line , |3I.
Similarly, the'oxygen added
through this line |3I is consumed, or substan
tially consumed, when a further quantity of
oxygen is added through line |20, and the oxygen
added through line |20 is consumed through
combustion by the time the gases have attained
the level where the suspension of catalyst in
oxygen or air is added through line |08.
The sus
pension of catalyst is eventually withdrawn
through line |6--a from the top of the regenera
chamber, and it may be recovered :from the
Ratio oi' recycled catalyst torcontaminated cata 70 tion
flue gases by passing it through one or- more
lyst by weight from 0.5:1 to 6: 1. ì
'
, ,
Air or equivalent oxygen-containing gas used 2.5
to 3.5 cubic feet per minute measured at stand
ard conditions per pound of carbonaceous de
cyclone separators not shown in this Fig. 2 but
fully illustrated in Fig. 1.
.
rThe pressure in the regeneration chamber may
posits to be burned from the catalyst per hour. 76 vary between 1 and 30 atmospheres absolute. The
2,412,098
' 7
amount of cooled regenerated catalyst .added to
1.- In the method of regenerating a spent pow--
the regeneration vessel or chamber, -as compared
with the amount of spent catalyst added there
for,> may vary within the limits of from 0.75 to
6 parts by Weight of regenerated catalyst to 1
- dered catalyst i'n which said powdered catalyst
is suspended in a free-oxygen-containing gas and
part ofpspent catalyst. 'I'he amount of oxygen
added to conduits IIJ-a, w8', |20 and i3! will ob
viously depend on the amount required to consume
regenerated catalyst in a free-oxygen-containing
passed through a regeneration zone, the improve
ments which comprise suspending a hot, recently
gas, cooling the last-named catalystsuspenslon,
intermixing the suspension of regenerated and a
by oxidation the contaminants deposited on the
catalyst and the amount of spent catalyst passing 10 suspension of spent catalyst, discharging the
mixture into >the regeneration zone, maintaining
through the regeneration vessel lZ-a in a given
time. -Ordinarily the catalyst will contain from _ said mixture in said regeneration zone in a highly
agitated state by causing the mixture to iiow in
1% to 3% carbonaceous deposit by Weight, and
the reaction zone inv a multiplicity of 'vari-direc
it can be assumed that this is largely carbon, al
tional currents and for a suñ‘icient period of time
though, of course, there is some hydrogen present
to effect the desired regeneration, recovering the
in the form of hydrocarbons of high unsaturation.
total catalyst discharged from the regeneration
The amount of air supplied to the regeneration
zone and resuspending a portion of the hot re
vessel l2--a should be 2.5 to 3.5 cubic feet per
generated catalyst in additional free oxygen-con
minute measured at standard conditions per
l
pound of carbonaceous deposits to be burned from '20 taining gas as aforesaid.
2. In the method of regenerating spent pow-l
the catalyst per hour.
dered catalyst in which said powdered catalyst
` The temperature of the inlet air may vary from
is suspended in a free-oxygen-containing gas and
passed through a regeneration zone, the improve
atmospheric to 800° F. The temperature of'the
recycled catalyst may vary from 400° to 1100° F.
The temperature of the contaminated catalyst 25 ments which comprise suspending a hot, recently
regenerated catalyst in a free-oxygen-containing
gas, cooling the last-named suspension, suspend
ing a spent catalyst in a free-oxygen-containing
may vary from 650° to 1000° F. (depending on
the temperature in the catalytic conversion proc
ess which caused the contamination). The mini
mum temperature at any point in the regenera
gas, intermixing the suspensions of spent and re- '
generated catalysts, discharging the mixture into
tion chamber maybe from 750° to 950° F. The
a regeneration zone through a number of per
forated pipes extending vertically over a substan
tial portion of the regeneration zone and direct
temperature of the suspension leaving the cham
ber may be preferably from 1000° to 1100)’ F.,
but certainly Within the range from 900° to
1200u F.
_
ing flow horizontally into the regeneration zone`
~
so as to thoroughly agitate and intermix the mix
It is to be understood that the methods de
scribed above for regenerating the catalyst and
making it suitable for further use are also appli
ture within said regeneration zone, permitting
the catalyst suspension to remain resident in the
-regeneration zone in a highly agitated state un
cable to the reviviiication of spent clays from
der regeneration conditions for a sufficientperiod
other processes in which certain clays are ren
dered less active by deposits of combustible ma 40 of time to effect the desired regeneration, with
drawing the regenerated catalyst in suspension
terials.
V
l
from the regeneration zone and resuspending a
Having described the speciñc embodiments, -it
portion of the hot regenerated catalyst in addi
tional free oxygen-containing gas as aforesaid.
will be understood that the invention embraces
such other variations and modiñcations as come
within the spirit and scope thereof.
What we claim is:
45
JACKSON R. SCHONBERG.
DONALD L. CAMPBELL.
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