CA1104962A - Air distribution apparatus - Google Patents
Air distribution apparatusInfo
- Publication number
- CA1104962A CA1104962A CA296,664A CA296664A CA1104962A CA 1104962 A CA1104962 A CA 1104962A CA 296664 A CA296664 A CA 296664A CA 1104962 A CA1104962 A CA 1104962A
- Authority
- CA
- Canada
- Prior art keywords
- air
- nozzle
- header
- hollow
- catalyst
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
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- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G11/00—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils
- C10G11/14—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils with preheated moving solid catalysts
- C10G11/18—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils with preheated moving solid catalysts according to the "fluidised-bed" technique
- C10G11/182—Regeneration
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/90—Regeneration or reactivation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
- B01J37/12—Oxidising
- B01J37/14—Oxidising with gases containing free oxygen
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
- B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
- B01J8/1818—Feeding of the fluidising gas
Abstract
AIR DISTRIBUTION APPARATUS
(D#74,459-F) Abstract of the Disclosure An air distribution apparatus for delivering an oxygen-carrying gas such as air to a zone of spent catalyst in a regenerator for the purpose of combusting air with the spent catalyst in order to rejuvenate the catalyst. A
header support assembly is adapted for mounting in a re-generator which receives the spent catalyst. A hollow header ring is mounted onto the header support assembly and includes a plurality of openings each having a nozzle mounted therein. Air is supplied to the header support assembly and thus to the hollow header ring at a pressure sufficiently high to effect a maximum desired pressure differential between header pressure and pressure in the zone of spent catalyst to cause maximum uniform air distri-bution. The nozzles mounted in the openings in the header ring decrease air velocity between nozzle inlet and nozzle outlet in order to provide for maximum uniform air distri-bution without destruction of the catalyst.
-I-
(D#74,459-F) Abstract of the Disclosure An air distribution apparatus for delivering an oxygen-carrying gas such as air to a zone of spent catalyst in a regenerator for the purpose of combusting air with the spent catalyst in order to rejuvenate the catalyst. A
header support assembly is adapted for mounting in a re-generator which receives the spent catalyst. A hollow header ring is mounted onto the header support assembly and includes a plurality of openings each having a nozzle mounted therein. Air is supplied to the header support assembly and thus to the hollow header ring at a pressure sufficiently high to effect a maximum desired pressure differential between header pressure and pressure in the zone of spent catalyst to cause maximum uniform air distri-bution. The nozzles mounted in the openings in the header ring decrease air velocity between nozzle inlet and nozzle outlet in order to provide for maximum uniform air distri-bution without destruction of the catalyst.
-I-
Description
Background of the Invention The field of this invention i5 air distribution and in particular air dis~ribution in the ca~calyst regene-rator of a fluid catalytic cxacking unit.
U.S. Patent No. 3,433,733 discloses a method and apparatus for fluid catalytic cracking of a hydrocarbon feed stock in order to produce desired reaction products.
; Generally, the process consists of mixing together feed - stock and hot catalyst in a riser/reactor prior to entry into a tapered reactor/separator chamber. The catalyst is removed from the reac~or/separator chamber in a spent con-dition and is directed to a regenerator wherein the carbona-ceous deposit on the catalyst, referred to as "coke", is burned from the catalyst with air. The regenerated catalyst is then re-used in the process. In U.S0 Patent NOn 3,433,733, an air distributor is positioned in the lower portion of the regenerator for distributing an air supply into a zone of spent catalyst in the regeneratox. The efficiency of the regeneration process is dependent upon a uniform distribu-tion of air through the spent catalyst zone. It has beenfound desirable to distribute the air outwardly of the air distributor at certain pressure differentials between air pressure in the distributor and air pressure in the regene-rator to cause the air to e~fectively bubble and thus distri-bute through the zone of spent catalyst. However; it has also been found that the velocity of the air leaving the air ring may be so high at such desired pressure diferential levels that the air actually causes some attrition of the catalyst. In order to prevent this attrition, it has been necessary to deliver the air at pressures below the higher pressure differential levels for the most efficient distribution of the air through the spent catalyst zone in the regenerator.
United States Patent No. 3,912,~60 discloses an air distribution system for evenly distributing air in the spent catalyst zone of a regenera~or in a fluid catalytic cracking process. ~ horizontal distributing ring is positioned in the spent catalyst in the regenerator. The ring comprises two tapered semi-circular tubes which are interconnected at their small ends; a splitter tube joint and the two larger ends of the ~apered semi-cylindrical tubes are connected to a pressurized air supply. Air i.s dis- .
tributed outwardly into the spent catalyst zone o the regenerator through openings in the semi-cylindrical tubes.
Other patents of interest include United States Patent 3,~67,103 which discloses the utilization of Venturi-shaped nozzles for use in mixing a hydrocarbon ancl acid to form an emuls:ion in a catalyt:ic conversion apparakus. United States Patent No. 3,8~8,811 discloses a particular structure for a nozzle which discharges a liquid such as oil iIltO a fluidi.zed bed of particulate material such as catalyst in a fluid catalytic .cracking system. And, Uni.ted Stat~s Patent No. 3,632,304 discloses a .
heater nozzle which di.rects combustion gas into a reactor for providing a combustion gas stream for treating catalyst. None of these patents disclose structure which :is precisely capable of achi.eving the results of the invention set forth herein.
Summary of the Invention ~ccording to this invention there is provided an improved air distribution apparatus for delivering an oxygen-carrying gas such as air at high pressure to a xone of spent catalyst in a regenerator of a fluid catalytic cracking process with maximum desired pressure differential and at a velocity below a level which would damage the catalyst, comprising, (a) hollow cylindrical housing means for mounting in the regenerator, ~ :
(b) hollow header means mounted on said hollow cylindrical housin.g means, ;~
(c) a plurality of nozzle means supported by said hollow cyli:ndrical housing means and said hollow header means for receiving the high pressure air, and ~3 (d) each of said nozzle means having a bore divergence of a hal:f angle of less than 7 for decreasing the delivered air velocity to a spent catalyst non-damaging velocity.
According to one embodiment of the invent:ion an improved air dis-tribution apparatus for delivering an oxygen-carrying gas such as air at high pressure to a zone of spent catalyst in a regenerator of a fluid catalytic cracking process with maximum desired pressure differential and at a velocity below a level which would damage the catalyst, comprises, (a) a header support assembly adapted for mounting in a regenerator of a fluid catalytic cracking process, said header support assembly supporting a hollow header ring having a plurality of openings therein, ~b) said header support assembly comprising a first cylindrical housing means for supporting said hollow header ring, ~c) an air supply line attached to said header support assembly arld air supply mcans Eor supplylng air through said.air supply line -to said llollow header ring at a pressure which causcs a maximum effective pressure differential between said ring and in said regenerator, (d) a plurallty of nozzles and mount means mounting said nozzles in said openings in said header ring, each of said nozzles having a bore therethrough which forms a nozzle inlet which initially receives air from said header ring and a nozzle exit Eor directing air outwardly into such spent catalyst zone, and ~e) each of sai.d nozzle bores d:iverging .-Erom said nozzle inlet to said nozzle outlet at a hal:E angle o:E less than 7 which decreases the velocity of said air from sai.d nozzle inlet to said nozzle exit to a level which will not substantially damage the catalyst.
According to another embodiment of the invention an improved air distribution apparatus for delivering an oxygen-carrying gas such as air at high pressure to a zone of spent catalyst in a regenerator of fluid catalytic cracking process with maximum desired pressure differential and at a velocity below a level which would damage ~he catalyst, comprises, ~a) a header support assembly adapted for mounting in a regenerator of a fluid catalytic cracking process, said header support assembly supporting a hollow header ri.ng having .
a plurality of openings therein, ~b) an air supply line attachcd to said header support assembly and air supply means :~or supplying air through ~l `,J
i2 said air supply line to said hollow header ring at a pressure which causes a maximum effective pressure differential between saicl ring and in said regenerator, ~c) a plurality of nozzles and mount means mounting said nozzles in said openings in said header ring, each of said nozzles having a bore therethrough which forms a nozzle inlet which initially receives air from said header ring and a nozzle exit for directing air outwardly into such spent catalyst zone, (d) each of said nozzle bores diverging from said nozzle inlet to said nozzle outlet at a half angle of 1 which decreases the velocity of said air from said nozzle inlet to said nozzle exit to a level which will not substantially damage the catalyst, (e) a first cylindrical hollow housing section having radial pipe members mounted therein and extend-ing outwardly to support said header ring, ~f) a second cylindrical hollow housing scction positioned on said first hous:ing secti.on, ~g) said first and sccond housing sect:ions having openings therei.n, ~h) a plura:lity oE nozzles mounted i.n said openings in said :Eirst and second housing sections, each nozzle having a bore therethrough diverging from a nozzle inlet to a nozzle exit, and ~i) mount means mounting said nozzle in said housing at the nozzle inlets thereof.
Brief Description of the Drawings In the accompanying drawings, which illustrate an exemplary embodiment of the present invention:
Figure 1 is a side view in section of a regenerator of a fluid catalytic cracking process having the air distribution system of this invention positioned therein;
Figure 2 is a sectional vlew of the air distribution system - ~.
header ring which mounts the air distribution nozzles of the preferred embodiment o-f this invention; and Figure 3 is a sectional view taken along line 3--3 of Figure 2 illustrating the structural detail of the air distribution system nozzles.
Description of the Preferred Embodiment .. . ..
Referring to the drawing, the letter R generally desig.nates a regenerator used in a flui.d catalytic cracking process such as disclosed in :
., ~) .
: United States Patent No. 3,433,733. The regenerator R includes a new and improved air distri.bution apparatus, generally designated by the letter A, adapted for mounting in the lower portion of the regenerator R. In a fluid catalytic cracking process such as disclosecl in United States Patent No. 3,~33,733, the lower portion 10 of the -regenelator R illustrated in Figure 1 actually receives spent catalyst from a reactor. The spent catalyst is in particulate form, the size of the particles being sufficiently small that the catalyst may be fluidized in air. The air distribution system A is designed to provide the necessary oxygen to combust with coke on the spen~ ca~alyst to combust and burn ~ a-the coke off the catalyst in order to rejuvenate the catalyst.
The rejuvenated catalyst is then re~used in the fluid cata-lytic cracking process. The spent catalyst is collected in a zone or bed 11 in the lower por~ion 10 of the regenerator R. The purpose of the air distribution system A is to distribute bubbled air through the spent catalyst zone or bed 11 so that the coke covering the spent catalyst is combusted with the air and burned off the catalyst.
In the preferred embodiment of this invention, the air distribution syste~ A includes a blower 12 which provides air under pressure to regenerator opening 14 through air supply line 15. A central housing 16 is mounted over the openiny 14 in the regenerator R.
The housing 16 includes a first housing section 16a and a second housing section 16b. The housing section 16a is basically a hollow, cylindrical structure which is mounted over the regenerator opening 14 by any suitable means such as welding. The housing section 15a includes a dome-shaped top section 17 having opening 17a therein.
The second housing section 16b is welded or other-wise mounted over the first housing section opening 17a.
The second housing section 16b is also a hollow and generally cylindrical section. The housing section 16b is enclosed at the top thereof.
The hollow housing se~tions 16a and 16b cooperate to form a plen~n ch~nber 18 which receives air through the air supply line 15. The first housing section 16a has a circumferential row of openings 19 positioned in substan-tially horizontal alig~nent. Each of the openinys 19 has mounted therein a nozzle N o~ the preferred embodiment of _5_ this invention as illustrated in detail in Fig~ 3. The second housing section 16b also has a row of circumferentially spaced openings 20 therein which receive nozzles N of this invention.
Three radial support arms 21, 22 and 23 are welded in three openings 24 in the first ho~sing section 16a. Each of the radial support arms 21-23 are hollow pipe memkers having an approximate L-shape as viewed in Fig. 1.
The three radial supports arms 21-23 cooperate with the first and second housing sections 16a and 16b to provide a header support assembly for supporting a hollow, header ring 25.
The header ring 25 includes three openings 26 which aliyn with and receive the radial support arms 21-23, which are attached to the header ring Z5 by welding or other suitable means. The header ring 25 further includes two rows 30 and 31 of nozzles N which are mounted in -two rows of header ring openings 30a and 31a, respe~tively. In addition, several drain nozzles D, which are of the same configuration as the nozzles N to be described herein, are positioned in header ring openings 33 which are located at the very bottom of the header ring 25 and are circumferentially spaced about the ring. The number of drain nozzles D is sub6tantially fewer than -the number of nozzles N in rows 30 and 31 in the header ring 25.
Complete distribution of air through the air dis-tribution system A into the spent catalyst zone 11 in re-generator R is critical to eficient rejuvenation of the catalyst. The nozzles N of the preferred embodiment of this invention are designed to deliver air to the spent: catalyst 6~
J~
zone 11 in the regenerator R at a safe velocity level in order ~o proviae for maximum dispersion of the air through the spent catalyst zone 11.
It has been found desirabl~ to have a sufficiently high pressure differential between the pressure of the air in the header ring 25 and the pressure of air ~xiting the nozzles N (which is the same as air pressure in the be~ 11) to cause the air to uniformly disperse for high area contact with the spent catalyst particles. However, it has been found that ai.r in prior art systems such as disclosed in U.S. Patent No. 3,912,460 which exits a header ring at such sufficiently high pressure dif~erential levels has a velocity that is so high that it may actually cause some attrition o the catalyst. The nozzles N of the preferred embodiment of this invention are designed to deliver air to the spent catalyst zone 11 at a velocity below a potentially damaging level.
Referring in particular to Figs. 2 and 3, each of the nozzles N is formed of a frustro-conical, cylindrical section 40 having a bore 41 therethrough. Each nozzle N
diverges or flares in the bore 41 from nozzle inlet or entrance 42 to nozzle exit 43. Each nozzle N is an inteyral unit ~ormed of cast Stelli-te or other suitable material.
Mount means yen~rally designated by the number 44 iæ provided for mounting each of the nozzles N in opening~
such as 30a in the header ring 25. The mount means 44 includes a mounting ring 46. When cast Stellite is utilized, the frustro-conical sec~ion 40 is formed by casting. However, cast ~tellite is no~ capable of direct attachment to the header ring 25 throuyh welding. In order to render the 7~
:
. , -.................. . ' ~ ' ' '.'. '~, ' ' ~
.
frusto-conical section 40 attachable to -the header ring 25 by welding, the mounting ring 46 is attached to the frusto-conical section 40 during casting. The mounting ring 46 may then be welded to the header ring 25. If another suitable nozzle material is utilized which can be welded to the header ring 25, it is contemplated to form the mounting ring as an inteyral portion with the frusto-conical section for direct welding connection to the header ring 25. Nozzle entrance 42 is formed by an inside nozzle rim 47 which is posi~ioned flush with interior wall 25a of the header ring 25.
The nozzl~ N may be defined as having a cross-sectional interior, ci.rcular area Ai at nozzle entrance 42 and a cross-sectional interior, circular area Ae a-t nozzle exit 43. The cross-sectional area Ai, and thus the interior diameter at -the nozzle entrance 42, is less than the cross-sectional area Ae, and thus the interior diameter at the nozzle e~it 43, such that the bore 41 tapers outwardly or diverges from the nozzle entrance 42 toward the nozzle exit 43. The half angle of such taper may be def.ined at 48 as being up to 15, but preferably 7~. The length 1 of the nozzle, as well as the angle 48 of taper, will vary accoxding to application .
The air distribution system A provides air to the header ring 25 in a pressure range to provide a sufficiently high pressure differential between the pressure in ring 25 ~which is approximately the same at entrance pressure Pi) -:
and the pressure in bed 11 (which is the same at nozzle exit pressure Pe) to provide for maximum uniform distribu~ion of : -air into bed 11. At such pressure levels, the tape:red interior bore 41 of the nozzle section 40 acts to reduce the entrance velocity Vi of air to a lesser exit velocity Ve which will not cause signiflcant damage to the catalyst.
Thus utilizing the nozzles N of this invention, the air distribution system A can deliver air to the spent catalyst zone 11 at maximum pressure differential levels to cause maximum uniform dispersion of the air into the spent catalyst zone 11 but at a s~fe, reduced velocity level which will not cause substantial attrition of the spent catalyst.
EXAMPLE
In a fluid catalytic cracking unit such as described in U.S. Patent No. 3,433,733, the nozzle N of thls invention has a length 1' exterior to the header 25 of three inches.
The area Ai at the nozzle entrance 42 is defined by a diameter of 1.55 inches (3.875 cm.) and the area Ae at the exit is defined by a diameter o 1.65 inches (4.19 cm.). The air pressure in the ring 25 is at 40.0 psi (2.80 kg./sq. cm.) and the pressure drop from the ring 25 to the bed 11 is 1.5 (105.95 gr./sq. cm.) to 2.5 psi (175.76 gr./sq. cm.). The divergence of the bore 41 causes a reduction in velocity from an entrance velocity Vi f 219 feet per second (66.75 m./sec.) to safe exlt velocity Ve f 175 feet per second (53.34 m./sec.), The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape and materials as well as in the details of the illustrated construction may be made without departing from the spirit of the invention.
U.S. Patent No. 3,433,733 discloses a method and apparatus for fluid catalytic cracking of a hydrocarbon feed stock in order to produce desired reaction products.
; Generally, the process consists of mixing together feed - stock and hot catalyst in a riser/reactor prior to entry into a tapered reactor/separator chamber. The catalyst is removed from the reac~or/separator chamber in a spent con-dition and is directed to a regenerator wherein the carbona-ceous deposit on the catalyst, referred to as "coke", is burned from the catalyst with air. The regenerated catalyst is then re-used in the process. In U.S0 Patent NOn 3,433,733, an air distributor is positioned in the lower portion of the regenerator for distributing an air supply into a zone of spent catalyst in the regeneratox. The efficiency of the regeneration process is dependent upon a uniform distribu-tion of air through the spent catalyst zone. It has beenfound desirable to distribute the air outwardly of the air distributor at certain pressure differentials between air pressure in the distributor and air pressure in the regene-rator to cause the air to e~fectively bubble and thus distri-bute through the zone of spent catalyst. However; it has also been found that the velocity of the air leaving the air ring may be so high at such desired pressure diferential levels that the air actually causes some attrition of the catalyst. In order to prevent this attrition, it has been necessary to deliver the air at pressures below the higher pressure differential levels for the most efficient distribution of the air through the spent catalyst zone in the regenerator.
United States Patent No. 3,912,~60 discloses an air distribution system for evenly distributing air in the spent catalyst zone of a regenera~or in a fluid catalytic cracking process. ~ horizontal distributing ring is positioned in the spent catalyst in the regenerator. The ring comprises two tapered semi-circular tubes which are interconnected at their small ends; a splitter tube joint and the two larger ends of the ~apered semi-cylindrical tubes are connected to a pressurized air supply. Air i.s dis- .
tributed outwardly into the spent catalyst zone o the regenerator through openings in the semi-cylindrical tubes.
Other patents of interest include United States Patent 3,~67,103 which discloses the utilization of Venturi-shaped nozzles for use in mixing a hydrocarbon ancl acid to form an emuls:ion in a catalyt:ic conversion apparakus. United States Patent No. 3,8~8,811 discloses a particular structure for a nozzle which discharges a liquid such as oil iIltO a fluidi.zed bed of particulate material such as catalyst in a fluid catalytic .cracking system. And, Uni.ted Stat~s Patent No. 3,632,304 discloses a .
heater nozzle which di.rects combustion gas into a reactor for providing a combustion gas stream for treating catalyst. None of these patents disclose structure which :is precisely capable of achi.eving the results of the invention set forth herein.
Summary of the Invention ~ccording to this invention there is provided an improved air distribution apparatus for delivering an oxygen-carrying gas such as air at high pressure to a xone of spent catalyst in a regenerator of a fluid catalytic cracking process with maximum desired pressure differential and at a velocity below a level which would damage the catalyst, comprising, (a) hollow cylindrical housing means for mounting in the regenerator, ~ :
(b) hollow header means mounted on said hollow cylindrical housin.g means, ;~
(c) a plurality of nozzle means supported by said hollow cyli:ndrical housing means and said hollow header means for receiving the high pressure air, and ~3 (d) each of said nozzle means having a bore divergence of a hal:f angle of less than 7 for decreasing the delivered air velocity to a spent catalyst non-damaging velocity.
According to one embodiment of the invent:ion an improved air dis-tribution apparatus for delivering an oxygen-carrying gas such as air at high pressure to a zone of spent catalyst in a regenerator of a fluid catalytic cracking process with maximum desired pressure differential and at a velocity below a level which would damage the catalyst, comprises, (a) a header support assembly adapted for mounting in a regenerator of a fluid catalytic cracking process, said header support assembly supporting a hollow header ring having a plurality of openings therein, ~b) said header support assembly comprising a first cylindrical housing means for supporting said hollow header ring, ~c) an air supply line attached to said header support assembly arld air supply mcans Eor supplylng air through said.air supply line -to said llollow header ring at a pressure which causcs a maximum effective pressure differential between said ring and in said regenerator, (d) a plurallty of nozzles and mount means mounting said nozzles in said openings in said header ring, each of said nozzles having a bore therethrough which forms a nozzle inlet which initially receives air from said header ring and a nozzle exit Eor directing air outwardly into such spent catalyst zone, and ~e) each of sai.d nozzle bores d:iverging .-Erom said nozzle inlet to said nozzle outlet at a hal:E angle o:E less than 7 which decreases the velocity of said air from sai.d nozzle inlet to said nozzle exit to a level which will not substantially damage the catalyst.
According to another embodiment of the invention an improved air distribution apparatus for delivering an oxygen-carrying gas such as air at high pressure to a zone of spent catalyst in a regenerator of fluid catalytic cracking process with maximum desired pressure differential and at a velocity below a level which would damage ~he catalyst, comprises, ~a) a header support assembly adapted for mounting in a regenerator of a fluid catalytic cracking process, said header support assembly supporting a hollow header ri.ng having .
a plurality of openings therein, ~b) an air supply line attachcd to said header support assembly and air supply means :~or supplying air through ~l `,J
i2 said air supply line to said hollow header ring at a pressure which causes a maximum effective pressure differential between saicl ring and in said regenerator, ~c) a plurality of nozzles and mount means mounting said nozzles in said openings in said header ring, each of said nozzles having a bore therethrough which forms a nozzle inlet which initially receives air from said header ring and a nozzle exit for directing air outwardly into such spent catalyst zone, (d) each of said nozzle bores diverging from said nozzle inlet to said nozzle outlet at a half angle of 1 which decreases the velocity of said air from said nozzle inlet to said nozzle exit to a level which will not substantially damage the catalyst, (e) a first cylindrical hollow housing section having radial pipe members mounted therein and extend-ing outwardly to support said header ring, ~f) a second cylindrical hollow housing scction positioned on said first hous:ing secti.on, ~g) said first and sccond housing sect:ions having openings therei.n, ~h) a plura:lity oE nozzles mounted i.n said openings in said :Eirst and second housing sections, each nozzle having a bore therethrough diverging from a nozzle inlet to a nozzle exit, and ~i) mount means mounting said nozzle in said housing at the nozzle inlets thereof.
Brief Description of the Drawings In the accompanying drawings, which illustrate an exemplary embodiment of the present invention:
Figure 1 is a side view in section of a regenerator of a fluid catalytic cracking process having the air distribution system of this invention positioned therein;
Figure 2 is a sectional vlew of the air distribution system - ~.
header ring which mounts the air distribution nozzles of the preferred embodiment o-f this invention; and Figure 3 is a sectional view taken along line 3--3 of Figure 2 illustrating the structural detail of the air distribution system nozzles.
Description of the Preferred Embodiment .. . ..
Referring to the drawing, the letter R generally desig.nates a regenerator used in a flui.d catalytic cracking process such as disclosed in :
., ~) .
: United States Patent No. 3,433,733. The regenerator R includes a new and improved air distri.bution apparatus, generally designated by the letter A, adapted for mounting in the lower portion of the regenerator R. In a fluid catalytic cracking process such as disclosecl in United States Patent No. 3,~33,733, the lower portion 10 of the -regenelator R illustrated in Figure 1 actually receives spent catalyst from a reactor. The spent catalyst is in particulate form, the size of the particles being sufficiently small that the catalyst may be fluidized in air. The air distribution system A is designed to provide the necessary oxygen to combust with coke on the spen~ ca~alyst to combust and burn ~ a-the coke off the catalyst in order to rejuvenate the catalyst.
The rejuvenated catalyst is then re~used in the fluid cata-lytic cracking process. The spent catalyst is collected in a zone or bed 11 in the lower por~ion 10 of the regenerator R. The purpose of the air distribution system A is to distribute bubbled air through the spent catalyst zone or bed 11 so that the coke covering the spent catalyst is combusted with the air and burned off the catalyst.
In the preferred embodiment of this invention, the air distribution syste~ A includes a blower 12 which provides air under pressure to regenerator opening 14 through air supply line 15. A central housing 16 is mounted over the openiny 14 in the regenerator R.
The housing 16 includes a first housing section 16a and a second housing section 16b. The housing section 16a is basically a hollow, cylindrical structure which is mounted over the regenerator opening 14 by any suitable means such as welding. The housing section 15a includes a dome-shaped top section 17 having opening 17a therein.
The second housing section 16b is welded or other-wise mounted over the first housing section opening 17a.
The second housing section 16b is also a hollow and generally cylindrical section. The housing section 16b is enclosed at the top thereof.
The hollow housing se~tions 16a and 16b cooperate to form a plen~n ch~nber 18 which receives air through the air supply line 15. The first housing section 16a has a circumferential row of openings 19 positioned in substan-tially horizontal alig~nent. Each of the openinys 19 has mounted therein a nozzle N o~ the preferred embodiment of _5_ this invention as illustrated in detail in Fig~ 3. The second housing section 16b also has a row of circumferentially spaced openings 20 therein which receive nozzles N of this invention.
Three radial support arms 21, 22 and 23 are welded in three openings 24 in the first ho~sing section 16a. Each of the radial support arms 21-23 are hollow pipe memkers having an approximate L-shape as viewed in Fig. 1.
The three radial supports arms 21-23 cooperate with the first and second housing sections 16a and 16b to provide a header support assembly for supporting a hollow, header ring 25.
The header ring 25 includes three openings 26 which aliyn with and receive the radial support arms 21-23, which are attached to the header ring Z5 by welding or other suitable means. The header ring 25 further includes two rows 30 and 31 of nozzles N which are mounted in -two rows of header ring openings 30a and 31a, respe~tively. In addition, several drain nozzles D, which are of the same configuration as the nozzles N to be described herein, are positioned in header ring openings 33 which are located at the very bottom of the header ring 25 and are circumferentially spaced about the ring. The number of drain nozzles D is sub6tantially fewer than -the number of nozzles N in rows 30 and 31 in the header ring 25.
Complete distribution of air through the air dis-tribution system A into the spent catalyst zone 11 in re-generator R is critical to eficient rejuvenation of the catalyst. The nozzles N of the preferred embodiment of this invention are designed to deliver air to the spent: catalyst 6~
J~
zone 11 in the regenerator R at a safe velocity level in order ~o proviae for maximum dispersion of the air through the spent catalyst zone 11.
It has been found desirabl~ to have a sufficiently high pressure differential between the pressure of the air in the header ring 25 and the pressure of air ~xiting the nozzles N (which is the same as air pressure in the be~ 11) to cause the air to uniformly disperse for high area contact with the spent catalyst particles. However, it has been found that ai.r in prior art systems such as disclosed in U.S. Patent No. 3,912,460 which exits a header ring at such sufficiently high pressure dif~erential levels has a velocity that is so high that it may actually cause some attrition o the catalyst. The nozzles N of the preferred embodiment of this invention are designed to deliver air to the spent catalyst zone 11 at a velocity below a potentially damaging level.
Referring in particular to Figs. 2 and 3, each of the nozzles N is formed of a frustro-conical, cylindrical section 40 having a bore 41 therethrough. Each nozzle N
diverges or flares in the bore 41 from nozzle inlet or entrance 42 to nozzle exit 43. Each nozzle N is an inteyral unit ~ormed of cast Stelli-te or other suitable material.
Mount means yen~rally designated by the number 44 iæ provided for mounting each of the nozzles N in opening~
such as 30a in the header ring 25. The mount means 44 includes a mounting ring 46. When cast Stellite is utilized, the frustro-conical sec~ion 40 is formed by casting. However, cast ~tellite is no~ capable of direct attachment to the header ring 25 throuyh welding. In order to render the 7~
:
. , -.................. . ' ~ ' ' '.'. '~, ' ' ~
.
frusto-conical section 40 attachable to -the header ring 25 by welding, the mounting ring 46 is attached to the frusto-conical section 40 during casting. The mounting ring 46 may then be welded to the header ring 25. If another suitable nozzle material is utilized which can be welded to the header ring 25, it is contemplated to form the mounting ring as an inteyral portion with the frusto-conical section for direct welding connection to the header ring 25. Nozzle entrance 42 is formed by an inside nozzle rim 47 which is posi~ioned flush with interior wall 25a of the header ring 25.
The nozzl~ N may be defined as having a cross-sectional interior, ci.rcular area Ai at nozzle entrance 42 and a cross-sectional interior, circular area Ae a-t nozzle exit 43. The cross-sectional area Ai, and thus the interior diameter at -the nozzle entrance 42, is less than the cross-sectional area Ae, and thus the interior diameter at the nozzle e~it 43, such that the bore 41 tapers outwardly or diverges from the nozzle entrance 42 toward the nozzle exit 43. The half angle of such taper may be def.ined at 48 as being up to 15, but preferably 7~. The length 1 of the nozzle, as well as the angle 48 of taper, will vary accoxding to application .
The air distribution system A provides air to the header ring 25 in a pressure range to provide a sufficiently high pressure differential between the pressure in ring 25 ~which is approximately the same at entrance pressure Pi) -:
and the pressure in bed 11 (which is the same at nozzle exit pressure Pe) to provide for maximum uniform distribu~ion of : -air into bed 11. At such pressure levels, the tape:red interior bore 41 of the nozzle section 40 acts to reduce the entrance velocity Vi of air to a lesser exit velocity Ve which will not cause signiflcant damage to the catalyst.
Thus utilizing the nozzles N of this invention, the air distribution system A can deliver air to the spent catalyst zone 11 at maximum pressure differential levels to cause maximum uniform dispersion of the air into the spent catalyst zone 11 but at a s~fe, reduced velocity level which will not cause substantial attrition of the spent catalyst.
EXAMPLE
In a fluid catalytic cracking unit such as described in U.S. Patent No. 3,433,733, the nozzle N of thls invention has a length 1' exterior to the header 25 of three inches.
The area Ai at the nozzle entrance 42 is defined by a diameter of 1.55 inches (3.875 cm.) and the area Ae at the exit is defined by a diameter o 1.65 inches (4.19 cm.). The air pressure in the ring 25 is at 40.0 psi (2.80 kg./sq. cm.) and the pressure drop from the ring 25 to the bed 11 is 1.5 (105.95 gr./sq. cm.) to 2.5 psi (175.76 gr./sq. cm.). The divergence of the bore 41 causes a reduction in velocity from an entrance velocity Vi f 219 feet per second (66.75 m./sec.) to safe exlt velocity Ve f 175 feet per second (53.34 m./sec.), The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape and materials as well as in the details of the illustrated construction may be made without departing from the spirit of the invention.
Claims (7)
1. An improved air distribution apparatus for delivering an oxygen-carrying gas such as air at high pressure to a zone of spent catalyst in a regenerator of a fluid catalytic cracking process with maximum desired pressure differential and at a velocity below a level which would damage the catalyst, comprising, (a) a header support assembly adapted for mounting in a regenerator of a fluid catalytic cracking process, said header support assembly supporting a hollow header ring having a plurality of openings therein, (b) said header support assembly comprising a first cylindrical housing means for supporting said hollow header ring, (c) an air supply line attached to said header support assembly and air supply means for supplying air through said air supply line to said hollow header ring at a pressure which causes a maximum effective pressure differential between said ring and in said regenerator, (d) a plurality of nozzles and mount means mounting said nozzles in said openings in said header ring, each of said nozzles having a bore therethrough which forms a nozzle inlet which initially receives air from said header ring and a nozzle exit for directing air outwardly into such spent catalyst zone, and (e) each of said nozzle bores diverging from said nozzle inlet to said nozzle outlet at a half angle of less than 7° which decreases the velocity of said air from said nozzle inlet to said nozzle exit to a level which will not substantially damage the catalyst.
2. The structure set forth in Claim 1, wherein, (a) a second cylindrical housing means is mounted on top of said first cylindrical housing means, both said cylindrical housing means having nozzles mounted therein.
3. The structure set forth in Claim 1, wherein, (a) said bore of said nozzle is flared outwardly from said nozzle inlet to said nozzle outlet at a half angle of substantially 3.5°.
4. An improved air distribution apparatus for delivering an oxygen-carrying gas such as air at high pressure to a zone of spent catalyst in a regenerator of fluid catalytic cracking process with maximum desired pressure differential and at a velocity below a level which would damage the catalyst, comprising, (a) a header support assembly adapted for mounting in a regenerator of a fluid catalytic cracking process, said header support assembly supporting a hollow header ring having a plurality of openings therein, (b) an air supply line attached to said header support assembly and air supply means for supplying air through said air supply line to said hollow header ring at a pressure which causes a maximum effective pressure differential between said ring and in said regenerator, (c) a plurality of nozzles and mount means mounting said nozzles in said openings in said header ring, each of said nozzles having a bore therethrough which forms a nozzle inlet which initially receives air from said header ring and a nozzle exit for directing air outwardly into such spent catalyst zone, (d) each of said nozzle bores diverging from said nozzle inlet to said nozzle outlet at a half angle of 1° which decreases the velocity of said air from said nozzle inlet to said nozzle exit to a level which will not substantially damage the catalyst, (e) a first cylindrical hollow housing section having radial pipe members mounted therein and extending outwardly to support said header ring, (f) a second cylindrical hollow housing section positioned on said first housing section, (g) said first and second housing sections having openings therein, (h) a plurality of nozzles mounted in said openings in said first and second housing sections, each nozzle having a bore therethrough diverging from a nozzle inlet to a nozzle exit, and (i) mount means mounting said nozzle in said housing at the nozzle inlets thereof.
5. An air distribution apparatus as recited in Claim 1 wherein, (a) second cylindrical hollow housing means being mounted on said first cylindrical hollow housing means, and (b) nozzles mounted in said second cylindrical housing means for delivering gas internally of said header ring for even distribution of high velocity gas to the catalyst.
6. An improved air distribution apparatus for delivering an oxygen-carrying gas such as air at high pressure to a zone of spent catalyst in a regenerator of a fluid catalytic cracking process with maximum desired pressure differential and at a velocity below a level which would damage the catalyst, comprising, (a) hollow cylindrical housing means for mounting in the regenerator, (b) hollow header means mounted on said hollow cylindrical housing means, (c) a plurality of nozzle means supported by said hollow cylindrical housing means and said hollow header means for receiving the high pressure air, and (d) each of said nozzle means having a bore divergence of a half angle of less than 7° for decreasing the delivered air velocity to a spent catalyst non-damaging velocity.
7. An air distribution apparatus as recited in Claim 6, comprising, (a) said hollow cylindrical housing means comprising a first and second cylindrical housing means, said second cylindrical housing means being mounted on said first cylindrical housing means, and (b) nozzle means for both said first and second cylindrical housing means.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US76801077A | 1977-02-11 | 1977-02-11 | |
| US768,010 | 1977-02-11 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1104962A true CA1104962A (en) | 1981-07-14 |
Family
ID=25081256
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA296,664A Expired CA1104962A (en) | 1977-02-11 | 1978-02-10 | Air distribution apparatus |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS5399077A (en) |
| CA (1) | CA1104962A (en) |
| DE (1) | DE2758327C2 (en) |
| FI (1) | FI773662A (en) |
| GB (1) | GB1568777A (en) |
| IT (1) | IT1174358B (en) |
| ZA (1) | ZA777029B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4673552A (en) * | 1982-09-09 | 1987-06-16 | Hydrocarbon Research, Inc. | Downwardly directed fluid flow distribution system for ebullated bed reactor |
| GB8504557D0 (en) * | 1985-02-22 | 1985-03-27 | Actio Product Consultants Ltd | Fluidised bed |
| CN108855648B (en) * | 2017-05-10 | 2021-06-18 | 中石油吉林化工工程有限公司 | Purging assembly and nozzle thereof |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3433733A (en) * | 1966-12-01 | 1969-03-18 | Texaco Inc | Method and apparatus for fluid catalytic cracking |
| US3974091A (en) * | 1974-08-29 | 1976-08-10 | Shell Oil Company | Fluidized bed regeneration of carbon-contaminated catalysts using gas discharge nozzles of specific dimensions |
-
1977
- 1977-11-22 GB GB48526/77A patent/GB1568777A/en not_active Expired
- 1977-11-25 ZA ZA00777029A patent/ZA777029B/en unknown
- 1977-12-02 FI FI773662A patent/FI773662A/en not_active Application Discontinuation
- 1977-12-27 DE DE2758327A patent/DE2758327C2/en not_active Expired
-
1978
- 1978-01-10 JP JP94078A patent/JPS5399077A/en active Pending
- 1978-02-10 CA CA296,664A patent/CA1104962A/en not_active Expired
- 1978-02-10 IT IT20171/78A patent/IT1174358B/en active
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5399077A (en) | 1978-08-30 |
| IT1174358B (en) | 1987-07-01 |
| ZA777029B (en) | 1979-04-25 |
| GB1568777A (en) | 1980-06-04 |
| IT7820171A0 (en) | 1978-02-10 |
| DE2758327C2 (en) | 1985-02-07 |
| DE2758327A1 (en) | 1978-09-14 |
| FI773662A (en) | 1978-08-12 |
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| MKEX | Expiry |