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Патент USA US3083092

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_ March 26, 1963
Filed Dec. 19, 1957
2O . 30.‘
33 L39
Carl E. Kleiber
Bywjw'j Attorney
Unite grates Patent O??ce
E. Kieiber, SQLEBS
éjhester RE‘ZJU‘
‘JRYMorris“ County,
til, assigno': to Essa Research and Engineering Com
Patented Mar. 26, 1963
trained ?nes into the atmosphere has tended to :add to
atmospheric pollution. Expensive equipment, such as
Cottrell precipitators, scrubbing facilities etc. may well
be required in order to operate within municipal regula
As was brie?y described, conventional systems have
employed pluralities of cyclones, e.g. 2 to 12 units or more
in parallel and/or in series, in an effort to reduce such
losses to a minimum. While these separation units have
The present invention is concerned with the more effec
a fair degree of et?ciency in solid ?nes collection under
tive recovery of ?ne solids entrained in up?owing gases. 10 ideally designed and perfectly smooth conditions within
More particularly, it deals with apparatus and process
the contacting chamber, such conditions are the exception
conditions ‘for recovering solids normally discharged from
rather than the rule. System surges associated with in
the gas outlets of cyclonic separators operating in the
strumentation problems as well as the usual operating up~
upper portion of a ?uidized solids gas-solids contacting
15 sets in ?uidized solids conditions, along with erosion and
pany, a corporation oi‘ Dela rare
lFiEedEee. 19, 12357, Ser. No. 703,918
(tCl. 23-284)
In recent years, ?uidized solids techniques have ‘assumed
increasing popularity in the petroleum and other allied
process industry. As is 'well known, the highly turbulent
damage to the cyclones themselves, detrimentally affect
the solids recovery ef?ciency. These upsets have resulted
in increased carryover of solids into the plenum chamber
and ultimate loss from the system.
nature of the solids bed generally employed ensures ex
In accordance with the present invention, solids losses
cellent mixing of solids, good gas-solids contact, and
vdue to surging and the less than perfect efficiency of any
highly uniform temperature levels throughout the ?uidized
separation system may be further reduced. More partic
ularly, the present system contemplates adapting the con
In brief compass, a conventional ?uidized solids opera
ventional plenum chamber to serve as an additional solids
as ‘for example ?uid catalytic cracking, comprises
' tion',
recovery stage by supplying means for withdrawing ?ne
injecting a volatilizable feed material into a mass of ?ne 25 solids de-entrained in the relatively large volume of the
particles maintained in a characteristic pseudo-liquid state.
plenum chamber. In speci?c aspects, a conduit is pro
After a certain residence interval in the ?uid bed, gases,
vided for returning ?nes to the fluid bed, or for withdraw
along with entrained ?ne solids, ?ow upwardly into the
ing separated ?nes from the plenum chamber and recover
dilute phase region of the gas-solids ‘contacting chamber,
ing them ‘as such. Heretofore, entrained solids settling
wherein they are subjected to the action of
out in the plenum chamber due to its increased area and
separation units, e.g. cyclones or the like. Collected
the swirling actions of the vapor discharge have merely
separated ?nes are normally returned to the solids bed
increased in amount until the solids are re-entrailned and
via diplegs which are appended on the cyclone units, and
carried out of the vessel by the up?owing vapor stream.
‘are a standard facility of this type of gas-solids separating
By practice of the present invention, these ?ne solids are
‘equipment, while thus treated gases are withdrawn over
recovered, and a considerable solids recovery credit added
to the gas-solids separation system. Existing structures
It has, heretofore, been standard practice in many such
may be thus modi?ed to secure additional bene?ts above
gas-solids contacting vessels, to flow separated vapors into
and beyond that contemplated at the time of their initial
an enlarged gas ‘collection zone, or plenum chamber, 40
whencefrom the gases are then generally discharged to
'the atmosphere .or passed to other processing facilities or
Since normally -a plurality of separators or
> equipment.
cyclones ‘are used, each having a relatively small gas exit
‘conduit when compared with the diameter of the vessel,
While the present invention is particularly desirable in
?uidized solids operation e.g. catalytic cracking, ?uid hy
droforrning, ?uid coking, ?uid bed regenera'tors, combus
tion zones, coal gasi?cation and carboniz-atiotn units, etc.,
it may be employed in various other gas-solids systems
the plenum chamber serves as a manifold for collecting 45 having a plenum chamber of the character described.
‘the discharge of the several lines, and acts to take up
It should be clearly understood that the terms “plenum
minor pressure surges in the overhead system. More
chamber,” “gas collecting zone,” “terminal area” etc. are
over, this enlarged gas collecting zone tends to» compensate
‘to ‘be interpreted as connoting the enlarged chamber or
‘for thermal expansion of the parts and attachments. in the
area employed in gas-solids contacting systems, to which
upper con?nes of the vessel, and is of considerably cheaper 50 the conventional solids separators (cyclone, etc.) dis
construction for effecting discharging of gases than would
charge, and whencefrom thus separated gases are with
be required if the cyclone outlet lines were individually
drawn from vthe system.
passed through the top of the contacting vessel shell.
The terms “vapors” and “gases” are to be understood
However, among the disadvantages of fluidized solids
as being used interchangeably.
system is the rather large losses of the very ?ne particles, 55
The various aspects of the present invention will be
e. g. 40 microns and smaller, in the overhead or stack gases.
In- order to maintain proper bed ?uidity, an appreciable
proportion of the bed solids must ‘be of the size range of
v?ne particles. Their loss due to entrainment necessitates
considerable effort in replacing them in the ?uidized bed.
~made more clearly apparent by reference to the following
Most importantly, in catalytic cracking, ?uid hydroform
ing and other systems employing relatively expensive con
having a particularly ?exible plenum chamber design
and operation.
description, example and accompanying drawings.
FIG. I illustrates a ?uidized solids catalytic reaction
zone operating in accordance with the present invention.
FIG. II depicts the upper part of solids-gas contactor
tacting solids this carryover of ?nes in overhead gases
results in solids losses and decreased plant processing
efficiency amounting to hundreds of thousands of dollars
per commercial unit. Additionally, the discharge of en
Turning to FIGURE I, there is shown, for the pur
poses of describing the present invention, catalytic reactor
ll) having a ?uidized mass 11 of catalytic particles there
in. As has ‘previously been brought out, the present in
vention has broad application and is not necessarily lim
ited to ?uidized catalytic conversions. However, the
value of the catalyst ?nes, both as measured in dollars
and operability of the ?uid bed, makes the present in
vention particularly desirable to ?uidized catalytic crack~
ing and hydroforming.
While the catalytic reactor, per so, does not constitute
out catalyst in ?owing to dipleg 28. If desired, as for
example when existing units are to be adapted for the
present invention, various other shaped chambers, elg.
substantially ?at bottomed or concaved upwards, may
be readily utilized.
Often, the natural vibrations of the equipment within
the fluid solids vessel during operations is su?icient to
cause de-entra-ined ?nes to flow into and down plenum
it will be given for the purpose of completeness.
chamber dipleg 28. Aeration facilities, such as steam
Fluid ‘bed 11 is supported on grid 18 or other well
10 tap 30 and/or dipleg aeration may additionally be pro
known supporting means, and is maintained in ?uid state
vided for aiding ?ne solids movement. Also, it may be
by means of volatilizable feed oil material and steam, with
advantageous to add relatively coarse solids to the gas
or without entrained solids therein, ?owing upwardly
collecting chamber as a means of promoting recovered
through line 14 into reactor 10. The catalytic particles
solids ?ow into the dipleg. This may be conveniently
are any conventional catalyst, e.g. silica-alumina mix 15 done
by means of a standpipe, leading into the plenum
ture, and are less than 1000 microns ‘in size. They pref
chamber, coarse solids being supplied from the reaction
'erably range from 0-150 microns in size, the major por
bed, regenerator or elsewhere.
'tion of the solids ranging between 20 to 80 microns in
With regard to the speci?c de-entrainment process oc'
diameter. The reaction bed is maintained at a tempera
curring in‘area 13, the plenum chamber is of considerably
ture of about ‘900-1200D F. by means of hot regenerated
greater volume and cross-section than the exit line 24
solids introduced thereto through line 15. One or more
and 34 of the separation units or the volume of the in
vertical partitions 36 divide the reactor 10 into a reac
separation units and hence gases entering the
tion and a stripping section. Generally, a portion of
chamber undergo a sizable reduction in velocity thus en
the ‘bed particles are, after occluded hydrocarbons are
couraging de-entrainment; Additionally, the swirling or
stripped by steam introduced by line 35 into stripping 25 rotating
action of the vapors and entrained solids leav
zone Y27 and by steam stripping in line 16, withdrawn
ing the cyclone outlets as they enter the plenum chamber
by means of funnel opening 17, and passed through line
aid in vapor and gas separation. Separation is further
16 to a combustion zone, not shown. Oxidation therein
improved by extension of the cyclone outlets above the
of carbonaceous residue deposited during the course of
25 of the chamber, as is shown in the drawing. A
the catalytic reaction serves to heatthe particles to requi 30 wall
quiescent zone is thus provided below the upper or ter
site temperatures, e.g. 50 to 200° F. above that of the
minal portions of the outlets, thereby minimizing com
reaction bed, for supplying thermal energy to the con
an essential part of this invention, avbriefldescijiption of
mingling of'up?owing vapors and de-entrained solids pass
version step.
ing downwardly. As illustrated, the heights of the out
Gasiform material, i.e. steam, volatilized and cracked
lets are preferably placed at different levels so as to ad
feed constituents, together with entrained tine solids gen 35 ditionally
minimize interference of vapors with solids
erally somewhat smaller in particle s'ze than the average
one or more thin plates or ribs 3-1
sized particle of the ?uidized dense bed catalyst pass up
may be placed somewhat above the lowermost point ‘of
wardly from the ‘fluid bed into dilute phase 12 there
tapering section 25 and extending radially outward for a
above. As'shown, a plurality of separation units, e.g.
portion of the tapering length’ of the plenum
cyclones 19 and 20 connected in series‘by'conduit 23 40
so as to promote such quiescent or solids settling
vand in‘parallel relationship with cyclones 32 and 37
zones. In somewhat similar fashion, and as more fully
similarly connected by conduit 38, serve to de-entrain
described in regard to FIGURE H, the area immediately
.the ?neisolids in accordance with standard separation
the cyclone outlets may be ba?‘led to prevent com
practice, the separated solids being returned to the re
mingling of adjacent outlet vapors so as to aid in solids
action bed'by diplegs 21, 22, ‘33 and 39 respectively.
45 gas separation in the plenum chamber zone.
The thus treated ‘gases are then passed into terminal
By way of illustrating the practical advantages of the
area or plenum chamber 13 by exit conduits 24 and 34,
present invention, without separately removing ?nes from
the chamber serving as a gas collecting manifold whence
the plenum chamber as presently taught, the system il
from the gases are removed’ overhead through line 26.
The gases are then normally sent to condensation, frac 50 lustrated has a solids separation efficiency of ‘about
99.98%. By employing the present invention, overall
tionation, subsequent processing, etc.
solids recovery of better than 99.99% may be realized.
Up to this point, the above description has related
When multiplied by the cost/unit of catalyst, direct cata
-to {features well known in the art. In former practice,
lyst savings of $100,000/year may thus be realized on an
any solids separating in chamber 13 merely accumulated
sized plant of about 25,000 bbls./day capacity.
in its lower portion until they were re-entrained in up 55
.However, there are other and additional bene?ts to'be
?owing gases and withdrawn overhead therewith.
gained by this added solids ?nes recovery including im
~ According to the present invention, means are provided
gas-solids contacting e?iciency and decreased at
for effecting improved separation of solids in chamber
mospheric pollution.
13 and for recovering tie-entrained solids therefrom.
.While a conduit, not shown, may be provided for re
purpose of illustrating the modi?cations of the present
moving solids from vessel 10 and recovering them as
invention, the ‘upper portion of regenerator or burner
a distinct ?ne solids mass, it is normally preferred to
return the ?nes to the reaction bed itself by one or more
vessel 100.
Within the vessel is a mass 101 of carbon
containing solids, e.g., coke particles from a fluid bed
~diplegs 28'. The solids thusirecovered are generally less
unit, undergoing combustion 'in the presence of
than 40 to 60 microns in diameter, normally of the or 65
oxygen-containing gas introduced thereto by means not
der of 10 to 40 microns. In :order to prevent vapors and
‘shown. Disposed in the upper portion'of vessel 100 are
catalyst ?ow directly from ‘the reaction bed to plenum
separator cyclones '105 and 106 connected by line 111.
chamber 1B,;dipleg 28 is provided with'a suitable seal
It should be understood the various other conventional
- arrangement, such as 'ba?ie plate 29, or a check valve,gas
seal,‘ ?apper valve etcl; not'illustrated. Of course, nu 70 separators, such as vanes, multicyclones, or the like,
might be alternatively employed. Fine solids~carrying
merous other conventional means may be employed for
line gas passes upwardly throughthe separators, through
_ accomplishing this'se‘al effect.
The plenum chamber of the present invention preferably
dpassageway 112 into terminal area 103 and thence out of
the contacting vessel by means of withdrawal conduit 14.
"has a vtapered lower or :?oor portion 25 of a conical or
Solids separated by the cyclones are generally returned
downwardly concaved cross-section so as to aid settled 75 "directly to the combustion bed by ‘diplegs 107 and 108.
catalyst. Gt course, the present invention is not limited
Seal plates N59 and 11% prevent excessive baclrtlow of
to the speci?c numerical values recited.
gas-solids from the bed into the diplegs.
In the particular modi?cation illustrated, the plenum
chamber 1633 has a hemispherically shaped lower ?oor
' ‘
portion ill-4- tor facilitating down?ow of solids into dipleg 5 Process:
1715. Separated ?ne solids are caused to migrate (by
Temperature of reaction-bed, ° F ____ __.'-I I.‘
vibrations, aeration, and/or gravity, etc.) to the lower
Size range of major portion of bed solids,
Table I
portion of the chamber. In some cases, it is desirable
to have a separate Withdrawal line
having external
valve 122 therein for removing ?ne, hot solids from the 10
Volumetric production rate of reactor
vessel. Thus, relatively coarse solids may be preferen
tially subjected to combustion while ?nes are recovered
Reactor pressure, p.s.i.g _____________ __
conditions and disposed of. Aeration taps H9 provide
for smooth solids ?ow through line
Alternatively, 15
Average super?cial velocity-t of vapors in
cyclone outlets 24 and 34, ft./sec____
Average velocity of vapors in plenum
dipleg 115 may have a branch line, not shown, for re
chamber 13, =ft./sec ________________ _._
and used as such or otherwise withdrawn under controlled
_________ __
Oil feed rate, gals/hr ______________ __
microns _________ __
vapors, std. cu. ft./hr__
_-_- 1,567,000
moval of recovered ?nes from the system.
Quantity of ?nes recovered from plenum
When it is desirable to return ?nes to the bed, the
chamber, lbs/hr _________________ __
solids are caused to ?OW down dipleg 115. This return
Table II
conduit may advan ageously have a rl-bend con?guration, 20
the upwardly directed leg lie serving as an added seal
against solids-vapor ?ow from the reaction bed. The
upper end of leg 11% preferably terminates with an 180°
bend for returning lines to ?uid bed Elli. It is preferred
to have leg 116 terminate at or somewhat above the level 25
of the bed (as shown) so as to reduce the pressure re—
sistance to ?ne particle flow. The rate of solids down
?ow through the dipleg is controlled by ?apper valve 12
Aeration line ll? provides a rising gas flow in let7 3.1.6 to
remove from the bottom of the dipleg 115' the collected 30
solid ?nes for transport and return to dense bed Ml if
there is insufficient solids outage from the plenum cham
Vessel height above grid plate (H), ft__
Height of vessel top section (h), ft____
Average diameter of vessel, ft ______ __
Total volume of terminal cyclones 204-32,
cu. ‘ft_____ ______________________ _._
Total volume of cyclone outlets 244-34,
_________________________ __
Diameter of upper portion of plenum
chamber (D), it ________________ _._
Maximum height of plenum chamber
(a), it _________________________ __
ber. Line 117 may also act as a vapor sealing means.
Horizontal slope of tapering portion
Returning to the gas lie-v1 pattern, it is esirable to ar
range the cyclone separators so as to establish clockwise
or counterclockwise flow in the plenum chamber, thus
° ___________________________ __
Volume of plenum chamber, cu. ft____
incrementally providing solids die-entrainment therein.
As shown, a relatively large, open-ended, cylindrical duct
Di?erence in projecting heights of outlets
113 is arranged above the upper end of outlet line 112 and 40
?xed in concentric relationship with respect to cyclone
outlet 132 as a means of mi -- - Zing comnaingling of up
Projecting height of cyclone outlet 24
(b), ft.1 ________________________ __
2d- and 34, it ____________________ _._
Length of rib 31, ft ________________ __
Length of conduit 23, ft ____________ _._
ill/‘bile not. illustrated in FIG. I, a cylindrical duct, 1.75
flowing gases and descending, or horizontally projected,
cu. ft. in volume and 1 ft. in height, may be placed 0.5 ft.
de-entrained solids. Other baffle con?gurations for pro
above cyclone outlet 24 so as to minimize commingling
of gasses and solids.
moting quiescent zones and gas-solids separation, such as
a diverging snout may be alternatively employed.
By Way of summary, the present invention is concerned
It becomes apparent that the present invention has
with the modi?cation of conventional plenum chambers
broad applications and may be used wherever gas-solids
so as to provide an additional stage of solids recovery.
separation units operate in conjunction with plenum cham
The increased recovery of ?ne particles thus obtained
bers regardless of whether the separation units be internal
reduces solids losses, and aids in maintenance of proper
or external of the principal reaction vessel. "further, it
?uidized solids conditions. Fundamentally, the present
is applicable to dilute phase or transfer line operation
and the like. it may be utilized in systems employing a
in 'ention teaches that means are provided for removing
and recovering de-entrained solids from the plenum
single cyclone, one or more series of cyclones, a series of 55 chamber. Numerous modi?cations may be made within
more than two cyclones, or simply two cyclones in
the spirit of the above concept, and the present invention
is to be interpreted, as broadly as the art permits, as
Solids de-entrainment in the
collecting zone may
reading thereon.
What is claimed is:
be enhanced by various means well known to those skilled
in an apparatus for contacting gases ‘and ?nely di
in the art. Additionally, while the drawings illustrate 60
vided solids including a vessel, gas-solids separation means
return of ?nes from the pie. urn chamber directly to the
arranged in the upper portion of said vessel, said gas
reaction or combustion bed, they may be circulated in
solids separation means including a plurality of sets of
numerous other patterns so as to make e?icient use of
the ?ne particles. Thus, they may be passed from the
cyclone separators in parallel, each set of cyclone sep
arators being in series, a gas collecting plenum chamber
plenum chamber to any or all of the following areas: 65
the solids inlet conduit to the reaction chamber, the
stripping zone, or the oil injector. llternatively, the
?nes may be passed from the plenum chamber of a
regenerator directly to the conversion step or vice versa. 70
To further clarify the nature of the present invention,
tabulated below is a speci?c example of the characteristic
arranged in the upper portion of said vessel for collecting
gas from said cyclone separators, the exit conduit from
each of said cyclone separator sets emptying into said
plenum chamber, said gas collecting plenum chamber
of greater volume than said gas solids separation
means, ‘a top outlet for ‘gas on said gas collecting plenum
chamber, a separate conduit extending down from said
features of the system shown in FXGURE I, based on
plenum chamber for downwardly removing ?ne solids
the ?uid bed catalytic conversion of a hydrocarbon gas
from said plenum chamber, said exit conduits extending
oil fraction boiling above 430° F. with an alumina-silica 75 ‘vertically up through the ?oor of and up into said plenum
chamber to'prdvide quiescent zones in said plenum
‘ 2,378,542 -
chamber ‘below the outlet portions of said exit conduits.
References Cited 'in-the ?le of this patent
Scheineman __________ _- Dec. 28, 1943
Edmister 1 ___________ _._ June 19, 1945
Martin _______________ __ May.6, 1947
> Matheson _~ ___________ __ Oct. 20, 1953
2,879,145 7
‘ Rice ________________ __ Mar. 24, 1959
Squires "7 ____________ __ Apr. 16, 1955
Crosby ______________ __ July 21, 1959
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