US2994659A

US2994659A - Method and apparatus for conversion of hydrocarbons

Info

Publication number: US2994659A
Application number: US846971A
Authority: US
Inventors: Charles E Slyngstad; Marvin F Nathan; Roland L Nagy
Original assignee: MW Kellogg Co
Current assignee: MW Kellogg Co
Priority date: 1959-10-16
Filing date: 1959-10-16
Publication date: 1961-08-01
Anticipated expiration: 1978-08-01

Description

Aug. 1, 196:.

c. E. SLYNGSTAD ET AL 2,994,659

METHOD AND APPARATUS FOR CONVERSION OF HYDROCARBONS Filed Oct. 16, 1959 FIG.|

REGENERATOR 2 Sheets-Sheet l REACTOR 22 INVENTORS CHARLES E.SLYNGSTAD MARVIN F. NATHAN ROLAND L. NAGY ATTORNEY AG E N Aug. 1, 1961 c. E. SLYNGSTAD ET AL 2,994,559

METHOD AND APPARATUS FOR CONVERSION OF HYDROCARBONS Filed Oct. 16, 1959 2 Sheets-Sheet 2 REGENERATOR Y REACTOR 94" -92 F|G.3 {we INVENTORS CHARLES E. SLYNGSTAD MARVIN F. NATHAN ROLAND L. N-AGY W4 W 7 BY a. ATTORNEY C ll/'1 United States Patent 2,994,659 METHOD AND APPARATUS FOR CONVERSION OF HYDROCARBONS Charles E. Slyngstad, Rutherford, N.J., Marvin F. Nathan, New York, N.Y., and Roland L. Nagy, Clifton, N.J., assignors to The M. W. Kellogg Company, Jersey City, N.J., a corporation of Delaware Filed Oct. 16, 1959, Ser. No. 846,971 21 Claims. (Cl. 208-113) This invention relates generally to an improved method for efiecting contact of reactant materials wi h fluidized finely divided solid contact material. More particularly, the invention is directed to an improved arrangement of apparatus for handling finely divided contact material for cyclic fiow through a system involving hydrocarbon conversion, stripping and regeneration wherein the solids are contacted with gaseous, vaporous and/ or liquid materials for conversion to desired products.

In a preferred embodiment, the invention is directed to a catalytic conversion apparatus or system wherein a combination reaction and stripping vessel is supported at substantially the same elevation as the regeneration vessel and finely divided solid contact material is conveyed through sloping standpipes (the angle of which is greater than the angle of repose of the catalyst) to the base of substantially vertical riser conduits which extend up wardly into said reaction and regeneration vessels.

It is an object of this invention to provide an improved arrangement of apparatus for handling finely divided solid contact material in a fluid-like condition such that there is a minimum amount of erosion of the apparatus.

It is another object of this invention to provide a system for controlling severity of operation and maximum recovery of desired products when converting reactant materials to desired products. I

The present invention applies and is particularly directed to a system and apparatus for efiecting the cracking of hydrocarbon feed materials such as gas oils, topped crudes, residual oils and other high-boiling hydrocarbon fractions known as reduced crudes or combinations of these materials in the presence of finely divided catalytic material maintained in suspension in a gasiform material either as a relatively dilute phase suspension and/or a dense phase suspension, depending upon the severity of operation desired.

One difiiculty in the cracking of hydrocarbons boiling above gas oil boiling range materials such as reduced crudes, is that these materials containing constituents which are not completely vaporized at the temperature of contact with the catalyst or during cracking and therefore liquid-like constituents are present which cause considerable trouble unless properly handled in the formation of catalyst agglomerants when mixed with a finely divided hot catalyst material. Accordingly, the apparatus of this invention is directed to and provides a system to overcome or substantially eliminate these diiliculties. That is, the reactant materials either liquid and/ or partially vaporized, depending upon the hydrocarbon feed material to be processed are atomized or broken up into relatively fine droplets with a suitable gasiform diluent material which additionally controls the hydrocarbon partial pressure and provides for more intimate contact of the hydrocarbon feed in relatively small droplets with the finely divided solid catalytic or contact material. The mixture of hydrocarbon and diluent material is then passed with suspended finely divided solids in the desired ratio of solids to hydrocarbon reactant upwardly through at'least one transfer line or riser cracking conduit which terminates in an enlarged disengaging or settling chamber. The products of reaction and finely divided solids are discharged from the riser and separated in the enlarged ice settling or disengaging chamber by substantially reducing the velocity and pressure of the mixture whereby the solids settle out and form a bed of solids which is maintained in a fluid-like condition in the lower portion of the settling chamber. This enlarged settling chamber provides many functions, including reduction of the hydrocarbon partial pressure to improve separation of catalyst from products of reaction, desorption of hydrocarbon material from the catalyst through cracking, as well as stripping with a suitable stripping agent, all of which is accomplished in a relatively dilute solid phase in the upper portion and a relatively dense fluid bed phase of solids in the lower portion of the disengaging and settling chamber. To facilitate separation of products of reaction from catalyst discharged from the riser conduit, a reduction in the'vertical velocity component of the mixture is effected by discharging the mixture through a plurality of openings in the upper periphery of the riser, which openings are in the form of elongated slots or the upper end of the riser may be capped by a spaced apart bafile member which acts to reduce the vertical velocity component of the mixture and deflect it outwardly into the enlarged settling chamber to facilitate separation by settling of entrained catalyst from reaction products. As hereinbefore indicated, hydrocarbons adsorbed on the catalyst which have been incompletely cracked or converted to desired products undergo further cracking in a soaking type of cracking operation, While the catalyst is maintained in a relatively dense fluidized condition in the lower portion of the settling zone. Gasiform material including stripping gas and stripped products of reaction pass upwardly through the dense bed of solids from the stripping zone. The catalyst in the lower portion of the settling chamber moves generally downwardly as a relatively dense fluidized bed of catalyst from the lower portion of the settling chamber directly into a stripping chamber, which is positioned below and contiguous therewith countercurrent to stripping gas introduced to the lower portion of the stripping chamber.

In one embodiment of this invention a single riserreactor is provided which is coaxially positioned within and extends upwardly through a stripping chamber into a disengaging or settling chamber. It is contemplated within one embodiment of providing the annular stripping chamber with a plurality of substantially vertically spaced apart transverse baffle members which extend across the annular stripping chamber to the wall of the riser conduit, thereby dividing the annular stripper into a plurality of separate vertical contact sections. This baflle arrangement improves the L/D ratio of the annular stripper and its stripping efiiciency over a stripping section having no bafiles therein.

In a preferred embodiment, the annular stripper is provided with a plurality of bafile members which may be generally referred to as disc and donut shaped baflle members and which are alternately staggered downwardly to provide intimate contact between a gasiform stripping agent introduced to the lower portion of the stripper as it passes upwardly through the stripper countercurrent to the downwardly moving catalyst. In this embodiment the alternately staggered bafile means provide for tortuous flow of catalyst downwardly through the stripping chamber, and it is important that the bafiles be inclined at an angle of at least about 45 and at least greater than the angle of repose of the catalyst in order that there will be little or no tendency of the catalyst to collect and remain on the surface of the bafiles. Although the baflle members may be completely impervious to the flow of stripping gas therethrough, it is within the scope of this invention to employ baffle members which are partially perforated in the lower or intermediate portion thereof andvwhich will permit flow of gaseous material upwardly forated baifle members, it is important that the perforated baflle members be designed to prevent channeling of the stripping gas as it passes upwardly through the catalyst. It is preferred, therefore, that only a portion'of the batfle member be perforated and preferably only about the lower half or third portion of the baflie be perforated to exclude any possibility of the stripping gas from bypassing or channeling through the downwardly moving mass of catalyst particularly at the wall of the stripper.

In another embodiment employing a plurality of riser reactor conduits, the stripping chamber is symmetrically or coaxially positioned with respect to the settling chamber such that the plurality of riser conduits extend into the settling chamber exterior to the stripping chamber. The stripping chamber is preferably a cylindrical section of smaller diameter than the enlarged settling chamber and extends downwardly from substantially the bottom of the settling chamber. However, it is to be understood that the stripper may be completely or partially within the settling chamber. In the preferred embodiment the enlarged cylindrical settling chamber is coaxially positioned with and in open communication with the lower cylindrical stripping chamber of smaller diameter with the large and small cylindrical chambers being connected by an inverted open end conical frustrunr member. In this arrangement the plurality of riser conduits extend through the conical frustrum and may terminate either in the lower and/ or upper portion of the enlarged cylindrical settling chamber. The cylindrical stripper chamber is preferably provided with a plurality of downwardly sloping disc and donut shaped baflle members similarly to that described hereinbefore with respect to the single riser reactor.

The stripped solids recovered in the lower portion of the stripping chamber are then passed to the inlet of a sloping standpipe which originates in the lower portion or bottom of the stripper and extends downwardly at an inclined angle of at least about 45 to the lower portion of a substantially vertical riser conduit positioned beneath and extending upwardly into the regenerator vessel. In the lower portion of the regenerator riser conduit the stripped solids are combined with a portion of the regeneration gas, such as air or an oxygen-containing gas, required to regenerate the solids and the mixture is then passed upwardly through the regeneration riser and discharged into either the upper, intermediate or lower portion of a dense fluidized bed of catalyst in the regeneration chamber. When discharging the catalyst from the riser in the upper portion of the dense bed of catalyst, it is essential that the oxygen content of the lift gas be kept at a sufficiently low concentration to assure substantially complete use thereof by burning such that uncombined oxygen will not pass into the dilute phase above the dense phase of catalyst. The additional oxygen containing regeneration gas required to complete regeneration of the solids which may be in the range of from about 65 percent to about 85 percent of the total amount of oxygen required to regenerate the catalyst is supplied separately to the lower portion of the dense fluidized bed of solids in the regenerator through suitable regeneration gas distribution mean-s which may be a plurality of distributor rings. A grid or perforated bafie inay also be positioned in the lower portion of the regeneration chamber, either above or below the riser discharge, to assist in uniformly distributing the additional regeneration gas passed to the lower portion of the dense fluid bed of solids to provide for more complete burning of carbonaceous materials deposited on the solids during the hydrocarbon conversion reactions. During the regeneration step the finely divided solids become heated'to an elevated temperature. The thus heated solid material is then withdrawn from below the upper level of the dense fluid bed of solids, preferably from the lower portion ofv the dense bed of solids and passed downwardly through one or more sloping standpipes to the base or lower portion of one or more riserreactors extending upwardly into the reactor vessel. The sloping standpipes employed in the apparatus of this invention are inclined at an angle of at least about 45 and preferably at least about 50 from the horizontal to assure flow of finely divided contact material through the standpipes.

The riser conduits employed in the apparatus of this invention are provided at the discharge end thereof with a suitable distributor device which will not only decrease the vertical velocity component of the materials passing upwardly through the riser, but will deflect the finely divided contact material outwardly into an enlarged disengaging chamber whereby the velootiy is reduced and separation of the finely divided solid material from the gasiform material is facilitated. One suitable distributor device which may be employed is knovm as a bird cage and is formed by capping the erid of the riser with a solid gas impervious metal plate and providing a plurality of elongated slots or openings adjacent to and around the periphery of the discharge end of the riser. It is important to provide the discharge slots with an area which is at least equal to the cross-sectional area of the riser and preferably greater than the riser cross-sectional area. Another suitable arrangement is to provide a deflector baffle member or plate above and spaced apart from the open upper end of the riser conduit which will deflect the upwardly flowing suspension outwardly.

In addition to the above, the riser conduits employed in the apparatus of this invention are provided with suitable gasiform inlet means for spaced apart addition of hydrocarbon feed and gasiform diluent to the reactor risers and spaced apart addition of regeneration gas to the regenerator-riser. In this preferred embodiment, inert lift gas such as steam or other suitable gasiform ma.- terial may be initially employed to facilitate flow of regenerated solids upwardly through the riser-reactors with the hydrocarbon feed being introduced at any desired point in the vertical length of the riser to obtain the desired severity of conversion of hydrocarbon feed. That is, the hydrocarbon feed may be introduced to the riser at the lower, intermediate or upper portions thereof. When low conversions per pass of the hydrocarbon feed are desired, the feed may be desirably introduced into the upper portion of the riser in order that the time of contact of the hydrocarbon feed with the catalyst may be of a relatively low order, amounting to even a fraction of a second. As herein indicated, one or more riserreactors may terminate in the lower portion of the settling chambers substantially adjacent to the catalyst entrance to the stripping chamber. This particular arrangement facilitates controlling hydrocarbon contact time with finely divided solids and permits separating hydrocarbon products from catalyst as rapidly as possible, thereby increasing the refiners control over the degree of conversion desired. When a higher conversion per pass or more severe conversion operation becomes desirable, the hydrocarbon feed may be introduced to the intermediate or lower portion of the riser reactor to obtain the desired increased contact time with the catalyst. When more severe operating conditions are required than can be obtained in the riser alone, the upper level of the bed of catalyst may be raised above the riser discharge such that the riser Will discharge into the dense fluidized bed of catalyst rather than above it.

It can be seen from the above that the improved system and arrangement of apparatus of this invention provides a method of operation which is desirably flexible for treating dissimilar hydrocarbon feed materials under a wide variety of severity of conversion conditions In another embodiment of this invention it is contemplated, particularly when employing a plurality of riserreactors, to terminate at least one riser-reactor in the lower portion of the settling chamber and one or more riser-reactors in the upper or intermediate portion of the settling chamber such that one and/or all of the riser outlets may or may not be submerged in the catalyst bed merely by adjusting the upper level of the dense phase catalyst bed. in this embodiment of the invention, the upper level of the fluidized bed of catalyst in the settling chamber may be adjusted such that one riserreactor discharges into the fluid bed of catalytic material with another riser-reactor terminating in the upper or intermediate portion of the settling chamber and above the upper level of the dense catalyst bed. This arrangement of apparatus is particularly desirable to the refiner when processing dissimilar hydrocarbon feed materials which require difierent severity conditions of operation for conversion into desired products.

In the conversion of high-boiling hydrocarbons, particularly residual oils, topped crudes and reduced crudes with finely divided catalytic material, relatively large amounts of hydrocarbonaceous material comes in contact with and is deposited upon the catalyst which is removed by a sequence of steps involving cracking to lower boiling and higher boiling materials, stripping and regeneration. As much of the hydrocarbonaceous material as possible is removed by cracking and stripping leaving carbonaceous residues which may be removed from the catalyst by a more drastic treatment involving burning in the presence of air, thereby heating the catalyst to an elevated temperature and suitably restoring the activity of the catalyst for recycle to the hydrocarbon conversion step. As a means of controlling regenerator temperature within desired limits during combustion of the carbonaceous residue a plurality of heat exchange coils are provided and arranged within the dense fluidized bed of catalyst in the regenerator chamber through which a suitable cooling fluid is circulated. Although a wide variety of cooling coil arrangements may be employed in the catalyst bed, it is preferred that the coils be of a bayonet type which projects into the catalyst bed and which may be individually controlled by suitable valve means for circulating desired quantities of cooling fluid. Thus the coils provided within the regeneration chamber may be conveniently utilized for the production of process steam and/ or preheating of hydrocarbon feed, or a closed cyclic system may be employed which circulates a suitable heat exchange medium between the coils and suitable heat recovery equipment such as steam boilers wherein process steam may be produced.

The principal conditions of operation, such as time, temperature and pressure governing the conversion of hydrocarbonaceous materials in the presence of finely divided solid catalytic material and the regeneration of such solid materials may be varied over a wide range of conditions and will depend for the most part upon the type of materials treated and the extent of conversion desired. Generally, it is applicants desire to maintain the temperature of the regenerator in the range of from about 1000 F. to about 1400 F. and preferably from about 1050 F. to about 1200 F., with the riser reactor being operated at a temperature in the range of from about 800 F. to about 1100 F. and preferably from about 900 F. to about 1025 F. Generally, the fluid bed of solids or catalyst formed by the catalyst discharged from the riser will be at a lower temperature and will be in the range of from about F. to about 200 F. lower than the riser temperature, usually from about 40 F. to about 100 F. lower than the riser temperature. As herein indicated, the time of contact of the hydrocarbon reactant with the catalyst is dependent upon the hydrocarbon feed being employed, the conversion desired, and may be in the range of from about 1 second to about 10 seconds depending upon the refractiveness of the hydrocarbons treated, catalyst to oil ratio employed, as well as the temperature employed. It is contemplated, therefor,

within the scope of this invention to employ catalyst to oil ratios in the range of from about 3 to about 15 to 1. Generally, the superficial gas velocities in the riser-reactor will be in the range of from about 5 feet per second to about 100 feet per second, with the velocities in the dense fluid bed phase, when employed, being maintained in the range of from about 1.0 feet per second to about 3.0 feet per second.

It is quite evident from the above that the improved arrangement of apparatus of this invention provides a system of desired flexibility for the conversion of various hydrocarbon feed materials, which is enhanced by proyiding for the separate introduction of ditferent hydrocarbon materials for prolonged or relatively short contact time with finely divided solids under desired conversion conditions. In connection with the above, recycle oil or residual oils, for example, may be introduced directly to the lower or upper portion of the dense catalyst bed with a fresh feed such as a gas oil or high boiling materials, including residual oils being introduced through the riser-reactor depending upon the conversion desired.

The improved arrangement of apparatus of this invention may be used in a wide variety of chemical and petroleum processes wherein a =finely divided solid particulate material is employed and the solid material employed will depend upon the reaction desired. Therefore, the solid material which may be substantially inert or catalytic in nature or a mixture of inerts and catalytic material utilizable in the apparatus of this invention are those which are capable of being regenerated and which substantially retain their solid subdivided state under the conditions to which they are exposed in the system. Accordingly, it is contemplated in an embodiment of this invention to employ, for example, activated naturally occurring cracking catalysts of the type known as filtrol, kaolin or other activated naturally occurring cracking catalysts, as well as synthetically prepared cracking catalyst containing silica and alumina with or Without additional well known promoters. In addition, it is contemplated employing solid subdivided inert material such as sand, pumice, spent cracking catalysts, kiesel guhr, petroleum coke, etc. with finely divided catalytic material in varying proportions, as well as mixtures of naturally occurring and synthetically prepared cracking catalysts. That is, from about 50 percent to about percent of finely divided solid relatively inert material may be employed in physical admixture with an active catalytic agent, or a mixture of synthetically prepared and naturally occurring silica-alumina cracking catalyst may be employed in physical admixture with from about 50 percent to about 95 percent of relatively inert finely divided solid material. In addition to the above, the finely divided solid contact material may be substantially inactive or used cracking catalysts to which is added fresh synthetic catalyst at a rate in the range of from about 0.5 pound to about 5 pounds/barrel of hydrocarbon feed to maintain the average catalyst activity at a desired value.

Having thus generally described the improved system and apparatus of this invention, reference is now had to the drawings which present diagrammatically preferred arrangements of apparatus of this invention.

FIGURE 1 presents diagrammatically a preferred arrangement of apparatus when employing a single riserreactor.

FIGURE 2 presents diagrammatically a preferred arrangement of apparatus when employing a plurality of riser-reactors.

FIGURE 3 presents diagrammatically a preferred arrangement of apparatus for introducing reactant material to the lower portion of the riser-reactors.

Referring now to FIGURE 1 a reduced crude feed of about 20 API gravity introduced by conduit 2 is admixed with steam introduced by conduit 84 and the mixture is then passed to the bottom of riser conduit 4 for admixture with finely divided catalyst introduced to the bot- 7 .tom of the riser by sloping standpipe 6. The mixture of catalyst, steam and hydrocarbon is then passed upwardly through riser 4 and is discharged into an enlarged vessel '8 through a plurality of discharge slots 10 at the upper end of the riser conduit. As discussed hereinbefore the hydrocarbon feed may be introduced to the riser at a plurality of

points

2, 2' and 2". When introducing hydrocarbon feed through inlets 2' or 2" gasiform lift gas such as steam will be introduced at the base of the riser and pass with the catalyst upwardly through the riser to the point of feed inlet. The mixture of catalyst and hydrocarbon product is discharged from the riser conduit into an enlarged vessel 8 whereby there is a substantial reduction in the velocity of the mixture permitting the catalyst to settle out forming a relatively dense fluid bed of catalyst 12 having an upper meniscus l4. Vaporous products of reaction and gasiform materials more 'fully described hereinafter pass through

cyclone separators

16 and 18 wherein finely divided entrained solid material is separated and returned by diplegs 20 to the dense catalyst bed. The vaporous materials are then removed from the top of the reactor by conduit 22'. Provisions are made by

conduits

24 and 26 for the introduction of additional hydrocarbon reactant material into the dense fluid bed of catalyst maintained in vessel 8. In the preferred arrangement of this apparatus a recycle oil is introduced by conduit 26 into the upper portion of the dense fluidized bed of catalyst 12, wherein its undergoes conversion into desired products. The finely divided catalyst discharged from riser 4 moves generally downwardly as a dense fluid bed 12 to an annular stripping section 28, which is contiguous with and below the disengaging vessel 8. The annular stripping section 28 is provided with a plurality of disc and donut shaped baffle members 30 which provide a tortuous path for flow of catalyst downwardly through the annular stripping chamber. The plurality of alternately staggered downwardly sloping annular baflle members are sloped at an angle greater than the angle of repose of the catalyst to be passed downwardly thereover in the annular stripping chamber. In the lower portion of the annular stripping chamber and beneath the lowermost baflie member is provided a suitable distributor ring 32 supplied by conduit 34 for the introduction of suitable gasiform stripping material to the lower portion of the stripping chamber and for passage upwardly therethrough. Stripped catalytic material is then withdrawn from substantially the base of the annular stripping chamber by sloping conduit 36 which conveys the stripped catalytic material to the lower portion of a riser conduit 38 positioned beneath and extending upwardly to the lower portion of a regeneration chamber 40. A suitable aerating gas such as steam may be introduced to sloping standpipe 36 by conduits 42 and 44. In the lower portion of riser conduit 38 a portion of the regeneration gas is introduced by conduit 46 which picks up stripped catalyst from the base of conduit 36 and passes the catalyst as a suspension upwardly through riser conduit 38 into the lower portion of regenerator -40. The suspension passed through riser 38 is discharged through a plurality of slots 48 in the upper periphery of the riser conduit and the suspension is then distributed into the lower portion of the relatively dense fluidized bed of catalyst 50 having an upper meniscus 52 undergoing regeneration in the regeneration vessel 40. Additional regeneration gas is introduced to the lower portion of the dense fluidized bed 59 by distributor ring 54 supplied by conduit 56. Although not specifically shown a distributor grid may be horizontally positioned across the regenerator between the riser discharge and the inlet to the sloping standpipe. Combustion gases or gaseous products of regeneration are removed from the upper surface of the dense fluidized catalyst bed and passed through

cyclone separators

58 and 60 where entrained finely divided solid material or catalyst is separated from the combustion gases'and returned by dipleg '62 to the dense catalyst bed phase. The flue gases are then removed from the upper portion of the regenerator by conduit 64. Provisions are made for introducing steam into the upper portion of the regenerator through distributor ring 66 supplied by conduit 68. In addition, provisions are made for the introduction of cooling fluid such as water through conduit 70 into the regenerator above the upper dense phase level to facilitate control of regenerator temperatures. The regenerator is also provided with a plurality of bayonet type heat exchange coils 72 to further facilitate control of the catalyst bed temperatures. A suitable cooling fluid is introduced to coil 72 by conduit 74 and removed by conduit 76. Regenerated catalyst is then removed from the dense fluid bed 50 and passed downwardly through sloping standpipe 6 to the base of riser 4. Suitable aeration gas may be introduced to sloping standpipe 6 by conduit 78. Suitable control valves and 82 are provided in the sloping standpipes for controlling the rate of catalyst circulation in the system.

FIGURE 2 presents diagrammatically an arrangement of apparatus similar to that shown and described in FIG- URE 1 employing a plurality of riser-reactors for treating hydrocarbon reactant material with finely divided contact material and wherein the finely divided contact material or catalyst is stripped in a cylindrical chamber which is in open communication with and extends below in a coaxial position with respect to the disengaging chamber. In the apparatus of FIGURE 2 a hydrocarbon feed introduced by conduit 99 is split into two

streams

92 and 94. Dispersion steam introduced by conduit 96 is split into two

streams

98 and 100 for ad mixture with the hydrocarbon in

streams

92 and 94. The hydrocarbon feed and dispersion steam in

conduits

92 and 94 are separately introduced into the lower portion of substantially

vertical riser conduits

102 and 104 wherein the hydrocarbon feed is admixed with finely divided catalyst and passed upwardly through the risers at a relatively dilute suspension into a disengaging or settling chamber 106. Provision is also made in this embodiment for the spaced addition of hydrocarbon feed through inlets 92', 92", 94' and 94" for the reasons and in the manner herein discussed. Disengaging chamber 106 is an enlarged cylindrical chamber having a dome shaped upper portion and a conical shaped lower portion. A stripping chamber 108 of smaller diameter than said disengaging chamber is coaxially positioned with and extends downwardly from the conical bottom of the disengaging chamber 106. The

riser conduits

102 and 104 extend through the conical bottom of the disengaging chamber into the lower portion thereof. The mixture of catalyst, steam and hydrocarbon reactant passed upwardly through the risers discharge into the disengaging vessel through a plurality of discharge slots 110 around the upper periphery and at the discharge end of the risers. By this arrangement, the mixture of catalyst and hydrocarbon reaction products passing through the riser at a relatively high velocity upon discharge through the slots into the disengaging chamber experiences a substantial reduction in the vertical velocity component of the mixture thereby facilitating the separation of entrained catalyst particles from hydrocarbon products. The catalyst then due to its reduction in velocity settles out to form a bed of finely divided catalyst 112 therebelow having an upper meniscus 114 in the lower portion of the disengaging chamber. The products of reaction including stripped products of reaction more fully described hereinafter then pass through a series of

cyclones

116 and 118 having diplegs 129 wherein entrained finely divided catalyst is further separated from the reaction products and returned to the bed of catalyst by diplegs 120 with the hydrocarbon products being removed from the upper portion of the disengaging chamber by conduit 122 for further processing into desired products. As hereinbefore indicated a coaxially positioned stripping chamber 108 open at its upper end is positioned beneath and connected to the conical bottom of the disengaging chamber to permit downward flow of finely divided catalyst from the bottom of the disengaging chamber directly to the stripping chamber countercurrent to stripping gas passed upwardly therethrough and introduced to the lower portion of the stripping chamber by distributor ring 124 supplied by conduit 126. The stripping chamber is provided with a plurality of downwardly sloping and alternately staggered disc and donut shaped baflle members 128 having sufficient slope to substantially avoid accumulation of catalyst therein and which provide a tortuous flow for the catalyst passing downwardly through the stripping chamber. The stripping gas passes upwardly through the chamber in intimate contact with the downwardly moving catalyst and then into and through the bed of catalyst in the lower portion of the disengaging chamber, thereby further stripping the catalyst as a fluidized bed of catalyst 112. Additional means may be provided for introducing a gasiform stripping material into the lower portion of the catalyst bed 112, if desired. In addition, it is to be understood that the upper meniscus 114 of catalyst bed 112 may be above the discharge slots 110 of the plurality of riser conduits, particularly when it is desired to increase the severity of treatment of the hydrocarbon feed. Stripped finely divided catalyst or contact material is removed from the bottom of stripper S and passed downwardly by sloping standpipe 130 containing flow control valve 132 to the lower portion of a riser conduit 134. Regeneration gas such as air or a portion of the air required to regenerate the catalyst is supplied to the bottom of riser conduit 134 by conduit 136 wherein it picks up stripped catalyst from sloping standpipe 130 and is conveyed with the catalyst upwardly through riser conduit 134 into the lower portion of a regenerator chamber 138. Provision is also made at 135 and 137 for incrementally supplying regeneration gas or a suitable lift gas to the regenerator riser. The discharge end of riser conduit 134 is provided with suitable means 140 which may be in the form of slots for discharging regeneration gas and entrained catalyst into the lower portion of the regenerator chamber 138 and below a distributor 'grid 142, which grid substantially uniformly distributes the catalyst into the relatively dense fluidized bed of catalyst 144 undergoing regeneration in the regeneration chamber. Additional regeneration gas is supplied beneath the grid 142 by distributor ring 146 supplied by conduit 148. That is, the additional regeneration gas required to complete.

regeneration of the catalyst is supplied in this specific embodiment by distributor ring 146 which gas passes upwardly through grid 142 into the catalyst bed 144. As a means for controlling temperatures in the dense fluidized bed of catalyst in the regeneration chamber, suit- .able heat exchange coils 150 are provided in the catalyst bed. Flue gas product of the regeneration step containing entrained catalyst fines is passed through a series of

cyclone separators

152 and 154 having diplegs 156 wherein the entrained catalyst is separated from the flue gas and returned to the catalyst bed by diplegs 156. The flue gas recovered from the cyclone separator is withdrawn from the upper portion of the regenerator chamber by conduit 158. In the specific embodiment of FIG- URE 2 a plurality of sloping

standpipes

160 and 162 are provided for passing regenerated catalytic material from the dense bed of catalyst in the regenerator chamber to the lower portion of

riser conduits

102 and 104. In this specific arrangement of apparatus the inlet to sloping

standpipes

160 and 162 is positioned above distributor grid 142 for withdrawal of regenerated catalyst and passage downwardly through the sloping standpipes to the bottom of

risers

102 and 104 with the catalyst flow in the sloping standpipes being controlled by

valves

164 and 168, thereby completing the cyclic circulation of 1O finely divided contact material or catalyst through the system.

FIGURE 3 discloses diagrammatically a preferred nozzle arrangement for the introduction of gasiform material to the base of a riser conduit such as employed in the apparatus herein described, particularly for admixing hydrocarbon reactant material with finely divided catalytic material and conveying the mixture upwardly through the riser as a suspension. Although the specific arrangement may be used in any or all of the riser conduits, it will be specifically discussed by way of example in connection with riser conduit 4 to which catalyst is introduced by sloping conduit 6. The hydrocarbon feed is introduced in this specific embodiment to the lower portion of riser 4 by conduit 2 in admixture with steam introduced by conduit 84 to nozzle surrounded by an anular nozzle 172 through which steam is passed not only as blanket steam to reduce any tendency of overheating the hydrocarbon feed nozzle, but also to improve mixing of catalyst with feed discharged from nozzle 170. It is important that the upper edge or discharge end of nozzle 170 be above the center line of sloping conduit 6. By operating in this manner, high boiling hydrocarbons, such as reduced crudes, are effectively mixed with and dispersed in the catalyst, thereby minimizing the tendency of overheating of the feed nozzle and coking of hydrocarbons therein. In addition, flufiing steam is introduced by conduit 174 at the base of riser 4 and around annular nozzle 172 to prevent catalyst from defluidizing and plugging up the bottom of the riser.

Example As an example of the specific method of operation of the system described in FIGURE 1 above, the following operating conditions are presented.

Reactor temperature, F 930 Reactor pressure, p.s.i.g 9

Feed rate, b.p.s.d 8,740 Feed gravity, API 20 Diluent steam, lbs/hr 20,000 W./hr./w. 2.8 Cat/oil weight basis throughput 9.15 Riser catalyst density, lbs/cu. ft 10.0 Reactor bed density, lbs/cu. ft 35 CatalystSilica alumina.

Reactor diameter, I.D., ft l8 Reactor height, feet 31 Stripper height, feet 12 Stripping steam, lbs./ hr 11,000 Reactor-riser diameter, inches I.D 27 Reactor-riser (4) length, feet 60 Regenerator-riser length, feet 39 Regenerator-riser (38) diameter, inches I.D 33 Regeneration air lbs/hr. to riser 50,000

Regenerator air to regenerator 1bs./hr 210,500 Regenerator diameter, 1.1)., feet 32 Regenerator height, feet 27 Regenerator temperature, F 1,125 Regenerator pressure, p.s.i.g 10.0 Regenerator bed density, lbs./ cu. ft 30 Catalyst density riser (38), lbs./cu. ft 5.0 Throughput ratio, v./v 2.0

Example As an example of the specific method of operation of the system described in FIGURE 2 above, the following operating conditions are presented.

Reactor temperature, F 900 Reactor pressure, p.s.i.g 9.0 Total feed rate, b.p.s.d. (per riser) 11,900 Total feed gravity, API 25.8 Diluent steam lbs/hr. (per riser) 14,100 Cat/oil weight basis throughput 8.2 Riser catalyst density, lbs./cu. ft 1.71 Reactor bed density, lbs/cu. ft 35 Catalyst-Silica-alumina.

Reactor height, feet 15.0 Reactor diameter, I.D., feet 25.0 Stripper height, feet 15.0 Stripper diameter, I.D., feet 10.0 Stripping steam, lbs/hr 12,750 Reactor-riser diameter, inches I.D. (each) 50 Reactor-riser length, feet 63 Regenerator-riser length, feet 37 Regenerator-riser diameter, inches, I.D 60 Regeneration air, lbs./ hr. to riser 90,500

Regeneration m'r to regenerator, lbs/hr 271,500

Regenerator diameter, I.D., feet 39.3 Regenerator height, feet 35.0 Regenerator temperature, F 1,100 Regenerator pressure, p.s.i.g 8.1 Regenerator bed density, lbs./ cu. ft 30 Catalyst density regenerator riser, lbs./ cu. ft 2.90 Throughput ratio 1.12

sel, at least one open end sloping standpipe extending downwardly from the lower portion of said stripping chamber which is connected at its lower end to a first substantially vertical riser conduit, said first substantially vertical riser conduit extending upwardly into said regenerator chamber, at least one open end sloping standpipe extending downwardly from within said regenerator chamber which is connected at its lower end to at least one substantially vertical second riser conduit, said second substantially vertical riser conduit extending upwardly into said reactor chamber, means for separately introducing gasiform material to each of said substantially vertical riser conduits at spaced apart intervals through the length thereof, means for separately introducing gasiform material to the lower portion of said regenerator chamber external to said first riser conduit, means for introducing gasiform material to the lower portion of said stripping. chamber and means for withdrawing gasiform material from the upper portion of said regenerator chamber and said reactor chamber.

2. An apparatus comprising in combination an enlarged cylindrical substantially vertical reactor-disengaging chamber, a cylindrical stripping chamber of smaller diameter extending downwardly from said reactor-disengaging chamber and connected thereto by an open end conical bafile member, at least one first riser conduit open at its upper end extending from beneath said stripping chamber substantially vertically upwardly into said reactor-disengaging chamber, an enlarged cylindrical regenerator chamber positioned substantially adjacent to said reactor-disengaging chamber, a second riser conduit open at its upper end extending from beneath said regeneration chamber substantially vertically upwardly into said regeneration chamber, a first sloping standpipe extending downwardly from the lower portion of said stripping chamber and connected with the lower portion of said second riser conduit, at least one second sloping standpipe extending downwardly from within said regenerator chamber connected to the lower portion of said first riser conduit, means for separately introducing gasiform material to the lower, intermediate and upper portions of each of said riser conduits, means for separately introducing gasiform material to the lower portion of said regenerator chamber and said stripping chamber, means for removing gasiform material from the upper portion of said regenerator chamber and said reactor-disengaging chamber and means for cyclically circulating finely divided solid contact material sequentially through said reactor chamber, stripping chamber, regenerator chamber and back to said reactor chamber.

3. The apparatus of claim 2 wherein said first riser conduit is coaxially positioned with respect to said stripping chamber and extends upwardly therethrough to above a relatively dense fluid bed of contact material maintained in said reactor chamber.

4. The apparatus of claim 2 wherein a plurality of first riser conduits are employed which extend upwardly into said reactor-disengaging chamber exterior to said stripping chamber.

5. The apparatus of claim 4 wherein at least one riser conduit discharges above a relatively dense fluid bed of contact material maintained in said reactor disengaging chamber.

6. The apparatus of claim 2 wherein said second riser conduit terminates in the lower portion of said regenerator chamber and beneath a substantially horizontal grid means extending across the lower cross-sectional area of said regenerator chamber.

7. The apparatus of claim 2 wherein a plurality of sloping standpipes extend downwardly from the lower portion of the regenerator chamber to the lower portion of a plurality of riser conduits extending substantially vertically into said reactor-disengaging chamber through said conical bafiie.

8. The apparatus of claim 2 wherein said second riser conduit terminates in the upper portion of a relatively dense fluid bed of contact material in said regenerator chamber.

9. A method for contacting finely divided solid particle material with gasiform material and cyclically circulating said particle material through a reactor, at stripper and a regenerator which comprises passing finely divided solid material at elevated temperature and pressure conditions upwardly through at least one elongated substantially vertical riser-action zone which discharges into an enlarged disengaging zone, introducing gasiform material into said elongated reaction zone, separating gasiform material from solid particle material in said disengaging zone by reducing the velocity and pressure of the mixture discharges into said disengaging zone to form a relatively dense fluid bed of contact material in the lower portion of said disengaging zone, withdrawing gasiform material from the upper portion of said disengaging zone, passing said relatively dense fluid bed of solid material in said reaction zone generally downwardly from the bottom of said reaction zone directly into the top of a stripping zone in open communication therewith and countercurrent to gasiform material introduced to the lower portion of said stripping zone, withdrawing stripped solid contact material from the lower portion of said stripping zone and passing the same downwardly as a sloping elongated confined stream inclined at an angle of at least about 45 to the lower portion of a substantially vertical elongated confined stream originating beneath and extending into a regeneration zone, passing a relatively dilute oxygen-containing gas to the lower portion of said elongated confined stream originating beneath said regeneration zone for admixture with solid particle material introduced thereto, passing the mixture of dilute oxygen-containing gaseous material and solid particle material upwardly through said riser as a confined substantially vertical stream under conditions to partially heat said solid particle material to an elevated temperature, discharging said partially heated solid material into a relatively dense fluid bed of solid material in said regeneration zone, passing additional oxygen containing gas to substantially the lower portion of said dense fluid bed of solids in said regeneration zone to further heat said solids to an elevated temperature, withdrawing gaseous material from the upper portion of said regeneration zone, withdrawing solid material at an elevated temperature from said dense fluid bed through at least one elongated confined stream sloping downwardly at an angle of at least about 45 for passage of solid material to the lower portion of at least one substantially vertical elongated confined stream originating beneath said stripping zone and extending upwardly into said reaction zone, and introducing gasiform material into said substantially vertical elongated confined stream extending upwardly into said reaction zone.

10. The method of claim 9 wherein the elongated con fined stream extending upwardly into said reaction zone passes through said stripping zone to form an annular stripping section therein which is in open communication with a relatively dense fluid bed of solid material in the lower portion of the reaction zone.

11. The method of claim 9 wherein the elongated confined stream extending into said disengaging zone is a plurality of separate elongated confined streams which pass externally to said stripping zone and terminate in the upper and lower portion of the reaction zone.

12. The method of claim 11 wherein at least one elongated confined stream is employed to convey a mixture of hydrocarbon reactant and finely divided solid contact material under elevated temperature conversion conditions to above a relatively dense fluid bed of solid material in the reaction zone and at least one elongated confined stream is employed to convey finely divided solid contact material in the presence of a relatively inert gaseous material at an elevated temperature into the relatively dense fluid bed of solid contact material in the lower portion of said disengaging zone.

13. The method of claim 9 wherein relatively inert gaseous material is initially employed with the solid contact material passing upwardly in the elongated confined streams and the hydrocarbon reactant material is separately introduced to the elongated confined stream above the lower portion thereof for flow through only a portion of said elongated confined stream prior to being discharged into said reaction zone above a relatively dense fluid bed of solid material therein.

14. The method of claim 9 wherein the relatively dense fluid bed of contact material in the lower portion of the reaction zone has an upper level above the discharge of at least one elongated confined stream and is employed for the conversion of a hydrocarbon feed material different from that introduced to an elongated confined stream discharging above the upper level of the fluid bed of solid material in the reaction zone.

15. The method of claim 9 wherein a plurality of elongated substantially vertical confined streams are employed for the conversion of hydrocarbon reactant material which discharge in the upper portion of the reaction zone and above the relatively dense fluid bed of solid material in the lower portion of the reaction zone.

16. The method of claim 9 wherein the finely divided solid material comprises a mixture of finely divided relatively inert material in admixture with a minor portion of a catalytic material.

17. A method for cracking relatively high-boiling hydrocarbon reactant material to desired hydrocarbon prodnets in the presence of finely divided catalytic material which comprises passing an elongated substantially vertical confined stream of finely divided catalytic material at an elevated temperature upwardly to be discharged in an enlarged reaction zone above a relatively dense fluid bed of catalytic material maintained in the lower portion of the reaction zone, introducing a relatively high boiling hydrocarbon feed into said confined stream of catalytic material to efiect the desired conversion thereof under elevated temperature and pressure conditions to desired products, introducing a second hydrocarbon reactant material more refractive than said high-boiling hydrocarbon feed into the lower portion of said fluid bed of catalytic material, continuously passing catalytic material downwardly from the bottom of said reaction zone to a stripping zone countercurrent to stripping gas introduced to the lower portion of said stripping zone, passing stripped catalytic material from the lower portion of said stripping zone downwardly as an elongated confined stream inclined at an angle greater than the angle of repose of said catalytic material to the lower portion of an elongated substantially vertical first regeneration zone which discharges into an enlarged regeneration zone containing a relatively dense fluid bed of catalytic material in the lower portion thereof, passing catalytic material with a minor amount of oxygen containing regeneration gas upwardly through said first elongated regeneration zone under conditions to partially regenerate said catalytic material, passing partially regenerated catalytic material trom said first elongated regeneration zone into the fluid bed of catalytic material in the lower portion of said enlarged regeneration zone, passing additional regeneration gas into the lower portion of said fluid bed of catalyst in said regeneration zone to efiect more complete regeneration of said catalytic material, passing regenerated catalytic material from said fluid bed downwardly as an elongated confined stream inclined at an angle greater than the angle of repose of said catalytic material to the lower portion of said elongated substantially vertical confined stream of catalytic material passed upwardly into said reaction zone and introducing a relatively inert gaseous material to substantially the bottom of said stream of catalytic material passed to said reaction zone.

18. A method for cracking a residual oil feed in the presence of finely divided solid particle material having catalytic properties which comprises passing a plurality of separate confined streams of finely divided solid material at an elevated temperature with a relatively inert gaseous material substantially vertically upwardly and discharging said confined streams in an enlarged reaction zone, introducing residual oil feed to said confined streams above the bottom thereof under conditions to crack said residual oil to desired products, separating cracked products of reaction from finely divided solid material in said reaction zone to form a relatively dense fluid bed of solid material in the lower portion of said reaction zone beneath the discharge of said confined streams in said reaction zone, continuously moving finely divided solid material downwardly from the bottom of the reaction zone into a stripping zone, introducing stripping gas to the lower portion of said stripping zone for passage upwardly therethrough into the dense fluid bed of solid material in the lower portion of said reaction zone, withdrawing stripping gas and products of reaction from the upper portion of said reaction zone, passing stripped solid material to a regeneration zone and returning regenerated solid material to said plurality of confined streams.

19. A method for cracking a reduced crude hydrocarbon feed material in the presence of finely divided fiuidizable solid particle material comprising a mixture of relatively inert solid material with finely divided catalytic material which comprises passing finely divided solid material with relatively inert gaseous material as a suspension substantially vertically upwardly through an elongated confined zone which terminates Within and above the bottom of an enlarged reaction zone, introducing reduced crude feed material adm'med with relatively inert gaseous material into said elongated confined zone for contact with finely divided solid material passed upwardly therethrough under elevated temperature cracking conditions such that the time of contact of said feed material with said solid material is less than about 10 seconds, discharging hydrocarbon products of reaction and solid material from said elongated confined zone into said enlarged reaction zone under conditions to effect separation of hydrocarbon products from solid material with the separated solid material being collected as a relatively dense fluid bed of solid material in the lower portion of the enlarged reaction zone and beneath the discharge of said elongated confined zone, continuously moving solid material downwardly from said fluid bed into a stripping zone contiguous therewith such that stripping gas introduced to the lower portion of said stripping zone passes upwardly therethrough and into the fluid bed of solid material in the lower portion of said enlarged reaction zone, withdrawing stripped solid material from the lower portion of said stripping zone, regenerating said stripped solid material and returning the regenerated solid material to the lower portion of said elongated confined zone.

20. The method of claim 19 wherein a plurality of elongated confined zones are employed which discharge in the lower portion of said enlarged reaction zone adjacent to the entrance of solid material to said stripping zone and said hydrocarbon feed material is introduced to the intermediate portion of said elongated confined zones as relatively small droplets with relatively inert gaseous material.

21. A method for cracking hydrocarbon reactant materials which comprises passing a suspension of finely divided catalytic material admixed with a first hydrocarbon reactant material under elevated temperature cracking conditions as an elongated confined stream upwardly into a reaction zone for discharge above a relatively dense fluid bed of catalytic material maintained under lower temperature cracking conditions in the lower portion of the reaction zone, introducing a recycle hydrocarbon reactant material more refractory than said first hydrocarbon mate rial into said dense fluid bed of catalytic material, passing catalytic material entraining hydrocarbon material downwardly from said reaction zone into a stripping zone as a continuous bed of catalyst countercurrent to stripping gas introduced to the lower portion of said stripping zone so that entrained hydrocarbon material is stripped from the catalytic material and passes with stripping gas upwardly through the dense fluid bed of catalyst in said reaction zone, withdrawing hydrocarbon products and stripping gas as a combined stream from the upper portion of the reaction zone, withdrawing catalytic material containing carbonaceous deposits from the lower portion of said stripping zone, combining gaseous material containing oxygen with said withdrawn catalytic material to form a suspension which is passed upwardly through a first elongatedvconfined regeneration zone discharging into a dense fluid bed of catalytic material maintained in the lower portion of a second regeneration zone, passing the major portion of gaseous material containing oxygen required to regenerate the catalyst into the lower portion of said dense fluid bed of catalytic material in said regeneration zone to remove carbonaceous material from the catalyst by burning thereby heating the catalyst to an elevated temperature and withdrawing regenerated catalytic material at an elevated temperature from said dense fluid bed for passage to the lower portion of said elongated confined stream extending into said reaction zone.

References Cited in the file of this patent UNITED STATES PATENTS 2,827,422 Rehbein Mar. 18, 1958 2,902,432 Codet et a1. Sept. 1, 1959

Claims

9. A METHOD FOR CONTACTING FINELY DIVIDED SOLID PARTICLE MATERIAL WITH GASIFORM MATERIAL AND CYCLICALLY CIRCULATING SAID PARTICLE MATERIAL THROUGH A REACTOR, A STRIPPER AND A REGENERATOR WHICH COMPRISES PASSING FINELY DIVIDED SOLID MATERIAL AT ELEVATED TEMPERATURE AND PRESSURE CONDITIONS UPWARDLY THROUGH AT LEAST ONE ELONGATED SUBSTANTIALLY VERTICAL RISER-ACTION ZONE WHICH DISCHARGES INTO AN ENLARGED DISENGAGING ZONE, INTRODUCING GASIFORM MATERIAL INTO SAID ELONGATED REACTION ZONE, SEPARATING GASIFORM MATERIAL FROM SOLID PARTICLE MATERIAL IN SAID DISENGAGING ZONE BY REDUCING THE VELOCITY AND PRESSURE OF THE MIXTURE DISCHARGES INTO SAID DISENGAGING ZONE TO FORM A RELATIVELY DENSE FLUID BED OF CONTACT MATERIAL IN THE LOWER PORTION OF SAID DISENGAGING ZONE, WITHDRAWING GASIFORM MATERIAL FROM THE UPPER PORTION OF SAID DISENGAGING ZONE, PASSING SAID RELATIVELY DENSE FLUID BED OF SOLID MATERIAL IN SAID REACTION ZONE GENERALLY DOWNWARDLY FROM THE BOTTOM OF SAID REACTION ZONE DIRECTLY INTO THE TOP OF A STRIPPING ZONE IN OPEN COMMUNICATION THEREWITH AND COUNTERCURRENT TO GASIFORM MATERIAL INTRODUCED TO THE LOWER PORTION OF SAID STRIPPING ZONE, WITHDRAWING STRIPPED SOLID CONTACT MATERIAL FROM THE LOWER PORTION OF SAID STRIPPING ZONE AND PASSING THE SAME DOWNWARDLY AS A SLOPING ELONGATED CONFINED STREAM INCLINED AT AN ANGLE OF AT LEAST ABOUT 45* TO THE LOWER PORTION OF A SUBSTANTIALLY VERTICAL ELONGATED CONFINED STREAM ORIGINATING BENEATH AND EXTENDING INTO A REGENERATION ZONE, PASSING A RELATIVELY DILUTE OXYGEN-CONTAINING GAS TO THE LOWER PORTION OF SAID ELONGATED CONFINED STREAM ORIGINATING BENEATH SAID REGENERATION ZONE FOR ADMIXTURE WITH SOLID PARTICLE MATERIAL INTRODUCED THERETO, PASSING THE MIXTURE OF DILUTE OXYGEN-CONTAINING GASEOUS MATERIAL AND SOLID PARTICLE MATERIAL UPWARDLY THROUGH SAID RISER AS A CONFINED SUBSTANTIALLY VERTICAL STREAM UNDER CONDITIONS TO PARTIALLY HEAT SAID SOLID PARTICLE MATERIAL TO AN ELEVATED TEMPERATURE, DISCHARGING SAID PARTIALLY HEATED SOLID MATERIAL INTO A RELATIVELY DENSE FLUID BED OF SOLID MATERIAL IN SAID REGENERATION ZONE, PASSING ADDITIONAL OXYGEN CONTAINING GAS TO SUBSTANTIALLY THE LOWER PORTION OF SAID DENSE FLUID BED OF SOLIDS IN SAID REGENERATION ZONE TO FURTHER HEAT SAID SOLIDS TO AN ELEVATED TEMPERATURE, WITHDRAWING GASEOUS MATERIAL FROM THE UPPER PORTION OF SAID REGENERATION ZONE, WITHDRAWING SOLID MATERIAL AT AN ELEVATED TEMPERATURE FROM SAID DENSE FLUID BED THROUGH AT LEAST ONE ELONGATED CONFINED STREAM SLOPING DOWNWARDLY AT AN ANGLE OF AT LEAST ABOUT 45* FOR PASSAGE OF SOLID MATERIAL TO THE LOWER PORTION OF AT LEAST ONE SUBSTANTIALLY VERTICAL ELONGATED CONFINED STREAM ORIGINATING BENEATH SAID STRIPPING ZONE AND EXTENDING UPWARDLY INTO SAID REACTION ZONE, AND INTRODUCING GASIFORM MATERIAL INTO SAID SUBSTANTIALLY VERTICAL ELONGATED CONFINED STREAM EXTENDING UPWARDLY INTO SAID REACTION ZONE.