CA1159009A - Magnetically stabilized, fluidized beds - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Heat transfer in a hydrocarbon conversion pro-cess utilizing a magnetically stabilized fluid bed reactor and a magnetically stabilized catalyst regenerator is improved by the use of a fluidizable solids mixture com-prising substantially inert heat carrier particles and catalyst particles which may or may not be magnetizable wherein the inert particles have settling rates higher than the settling rates of the catalyst particles. The heat carrier particles and the catalyst particles are completely or partially separated in settling zones (3) and (7) associated with the reactor and regenerator. The separated heat carrier particles and catalyst particles are independently circulated between the reactor and regenerator so that the heat carrier particles can be passed through one or more heat exchangers (4) and (8) to provide the desired temperature levels in the system.

Description

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2 Many chemical and physical reactions such as

3 catalytic cracking, hydrogenation J oxidation, reduction,

4 drying, filtering, etc., are carried out in fluidized beds. A fluidized bed briefly consists of a mass of a 6 par~iculate solid material in which the individual parti-7 cles are in continuous motion relative to each other 8 whereby the mass or fluidized bed possesses the character-9 istics of a liquid. Like a liquid, it will flow or pour freely, there is a hydrostatic head pressure, it seeks a 11 constant level, it will permit the immersion of objects 12 and will support relatively buoyant objects, and in many 13 ot~er properties it acts like a liquid. A fluidized bed 14 is conventionally produced by effecting a flow of a fluid, usually gas, through a porous or perforate plate or mem-16 brane underlying the particulate mass, at a sufficient 17 rate to support the individual particles in a relatively 18 continuously moving manner. A minimum air flow or pres-19 sure drop is required to produce fluidization and is known as the incipient fluidizatio~ and is dependent on many 21 parameters including particle size, particle density, etc.
22 Any increase in the fluid flow beyond incipient fluidiza-23 tion causes an expansion of the fluidized bed to accommo-24 date the increased fluid flow until the fluid velocity exceeds the free falling velocity of the particles which 26 are then carried out of the apparatus.
27 Fluidized beds possess many desirable attributes, 28 for example, in temperature control, heat transfer, cata-29 lytic reactions, and various chemical and physical reac-tions such as oxidation, reduction, drying, polymerization, 31 coat~ng, diffusion, filtering and the like. However, the 32 establishment and maintenance of a stable fluidized bed by 33 conventional procedures is a sensitive and difficult pro-34 cess possessing many drawbacks and disadvantages.
Among the problems associated with fluidized 36 beds, a most basic one is that of bubble formation, fre-37 quently resulting in sluggina, channeling, spouting and ~J~

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1 pneumatic transport; this problem is most common in gas-2 fluidized systems. The problem necessitates critical flow 3 control and effects design factors such as minimum fluidi-4 zation velocities, pressure drops, particle sizes, etc.
Bubbling causes both chemical and mechanical diEficulties 6 for example, in gas-solids reactions gas bubbles may by-7 pass the particles altogether resulting in lowered con-8 tacting efficiencyO
9 Ideally, a fluidized bed should be free of bub-bles, homogeneous, maintain particle suspension and mani-11 fest non-critical flow velocity control for various bed 12 heights and bed densities. Many procedures and systems 13 have been proposed to effect improvements, for example, by 14 the use of baffles, gas distribution perforated plates, mechanical vibration and mixing devices, the use of mixed 16 particle sizes, gas plus liquid flow schemes, special flow 17 control valves, etc.
18 More recently, it has been disclosed in U.S.
19 Patent Nos. 3,304,249; 3,440~731; and 3,439,899 that certain improvements in fluidized beds can be effected by 21 applying a magnetic field to a fluidized bed of particu-22 late solids having ferromagnetic properties.
23 In general, the use of a magnetically stabilized, 24 fluidized bed minimizes solids back mixing and eliminates gas by-passing of the fluidized solids by preventing gas 26 bubble formation. The elimination of back mixing in cer-27 tain operations such as cat cracking, reforming, hydrofin-28 ing, hydrocracking, drying, etc., is particularly advan-29 tageous since it prevents back mixing of feed and products and thereby results in a greater selectivity to desirable 31 products. Unfortunately, the advantages associated with 32 the elimination of back mixing are partially offset by the 33 poorer heat transfer due to less violent agitation of the 34 fluidized solid particles. Such a decrease ir. heat trans-fer could cause hot spots on the catalyst particles and 36 leads to deactivation of the catalyst, side reactions, 37 selectivity loss, etc. In addition, temperature control 1 may be more difficult in certain reactions such as cata-2 lytic cracking, catalytic reforming, hydrocracking, hydro-3 genation, etc., which are highly exothermic or endothermic ~ in nature.
The problems associated with the use-of a magne-6 tically stabilized, fluidized bed as regards heat transfer 7 deficiencies are minimized or eliminated by the process of 8 the present invention which utilizes a particulate solids 9 mixture containing a plurality of separate, discrete (1) substantially inert heat carrier particles, and (2) magne-11 tizable catalyst particles where the heat carrier parti-12 cles are circulated independ~ntly of the catalyst parti-13 cles to provide the desired temperature levels in the sys-14 tem.
SUMMARY OF THE INVENTION
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16 A hydrocarbon conversion process whicht in a 17 first step, comprises (a) contacting a hydrocaxbon feed-18 stock in conversion, or reaction zone haviny a magnetic 19 field applied thereto with a fluidizable particulate solids mixture containing a plurality of separate discrete heat.
21 carrier particles and catalyst particles, said heat 22 carrier particles having settling rates higher than the 23 settling rates of said catalyst particles. In a first 24 embodiment, the second step is one (b) permitting said heat carrier particles to settle in preference 26 to the catalyst particles in a settling zone communicating 27 with said conversion zone; (c) circulating said catalyst 28 particles from the settling zone to a regeneration 29 zone having a magnetic field applied thereto; (d) circula-ting said heat carrier particles from the settling zone 31 to a heat exchanger means and thereafter to said 32 regeneration zone, said circulation of heat carrier 33 particles being independent of the circulation o~ catalyst 3~ particles; (e) contacting said catalyst particles in the presence of said heat carrier particles with oxygen at 36 elevated temperatures to burn coke deposited upon said catalyst particles; (f) permitting said heat carrier 1 particles to settle in preference to the catalyst particles 2 in a settling zone communicating with said regeneration 3 zone; (g) circulating said catalyst part.icles from the re-4 generation zone to a conversion zone having a magnet;c field applied thereto; and ~h~ circulating said heat car~
6 rier particles from the settling zone to a heat exchanger 7 means and thereafter to said con~ersion, or reaction zone~
8 sa;d circulation of heat carrier particles be;ng indepen-9 dent of the ~irculation of catalyst particles~
The heat carrier particles employed in sa;d 11 f;rst embodiment are substant;ally inert, and the other 12 component comprising the particulate solids mixture are 13 preferably magnetizable sol;ds~ By substantIally inert 14 is meant that the particles exert no catalytic influence.
on the chemical reaction occurring in the reaction zon~
16 The heat carrier particles will include any kno~n heat 17 transfer materials such as alumina, mullite~ porcelain~
18 steel, etc. The heat carrier particles will preferably 19 include ferromagnetic and ferrimagnet;c substance.s including but not limited to magnetic Fe304~ ;ron o~ide.
21 (Fe203), ferrites of the form MO.Fe203, wherein M is a 22 metal or mixture of metals such as ~n, Mn, Cu, etc.;
23 ferromagnetic elements including iron, nickel r cobalt and 24 gadolin;um, alloys of ferromagnetic elements, e.tc.
The catalyst particles employed in said first 26 embodiment are magnetizable, and will comprise one 27 or more of the aforedescri~ed ferromagnetic and ferri-28 magnetic substances and a catalyt;c material chosen to 29 effect thereaction desired. Accordingly, the magne~
tizable catalyst particles of the invention will include. a 31 vast number of conventional catalysts wh.ich are kno~n to 32 catalyze the desired reac~ion. Examples o catalysts use-33 ful herein include those catalysts conventionally employed 34 in such processes as fluid catalytic cracking, reforming~
35 hydrogenation, hydrocracking, isomerization, alkylation, 36 polymerization, oxidation, etc.
37 A second embodiment also relates to a process .

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1 wherein fluidizable catalyst solids are circulated 2 between a fluidized bed reaction zone, and said 3 particulate catalyst solids contacted with a hydrocarbon 4 feedstock resulting in the deposition of coke on said cata-

5 lyst solids and a fluidized bed regeneration zone in which

6 the catalyst particles having coke deposited thereon are

7 contacted with an oxygen-containing gas to remove said coke

8 by combustion. Said second embodiment is an improvement

9 which comprises (a) introducing into said reaction zone

10 particulate solids having f~rromagnet:ic properties so

11 that said hydrocarbon feedstock is contacted with a parti-

12 culate solids mixture containing a plurality of separate,

13 discrete ~1) magnetizable substantially non-catalytic

14 particles; and (2) non-magnetizable catalytic particles;
(b) applying a magnetic field to said reaction zone to 16 form a magnetically stabilized fluid bed in said reaction 17 zone; tc) withdrawing said particulate solids mixture from 18 the reactionzone; (d) separating said magnetizabla substan-19 tially non-catalytic particles from said non-ma~netizable 20 catalytic particles; and (e) returning said non-magnetiza-21 ble catalytic solids to said regeneration zone. In ordex 22 to compensate for heat effects in the reactort the 23 magnetizable substantially non-catalytic particles and 24 the non-magnetizable catalytic particles can be circulated 25 through the system at different rates~ In addition, this 26 embodiment contemplates the use of the heat exchanger to 27 remove or add heat to the magnetizable non-catalytic 28 particles.
29 In said second embodiment, the substantially 30 non-catalytic particles which comprise the particulate 31 solids mixture are magnetizable solids. By substantially 32 non-catalytic is meant that the particles exert no 33 catalytic influence on the chemical reaction occurring 34 in the reackion zone. These substantially non-catalytic 35 particles include ferromagnetic and ferrimagnetic 36 substances including but not limited to magnetic Fe304, 37 ~ iron oxide (Fe203), chromium dioxide, ferrltes of the ' :
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l form MO-Fe203, wherein M is a metal or mixture of 2 metals such as Zn, Mn, Cu, etc.; ferromagnetic elements 3 including iron, nickel, cobalt and gadolinium, alloys 4 of ferromagnetic elements, etc. The larger the magneti-zation of the particle, the higher will be the transition 6 velocity up to which the bed may be operated without 7 bubbling, all other factors held constant. Preferably, 8 the particle wlll have magnetization of at least 50 9 gauss, more preferably 250 gauss or greater.
The non-magnetizable catalytic particles will ll be chosen to effect the reaction desired. Accordingly, 12 the non-magnetizable catalytic particles of the invention 13 will include a vast number of conventional catalysts which 14 are known to catalyze the desired reaction. Examples of

15 catalysts useful herein include those catalysts conven-

16 tionally employed in such processes as fluid catalytic

17 crackingr reforming, hydrogenation, hydrocracking, isomeri-

18 zation, alkylation, polymerization, oxidation, etc.

19 The fluid catalytic cracking catalyst which

20 may be used in the process of the invention include the

21 highly active zeolite-containing catalysts and the

22 amorphous silica-alumina catalysts.

23 In general, the zeolite-type catalysts are

24 exemplified by those catalysts wherein a crystalline aluminosilicate is dispersed with a siliceous matrix.
26 Among the well recognized types of zeolites useful herein 27 are the "Type A", "Type Y", "Type X", "Type ZSM", 28 mordenite, faujasite, erionite, and the like. A further 29 description of these zeolites and their methods of preparation are given, for example, in U.S. Patents Nos.
31 2,~82,243; 2,882,24~; 3,130,007; 3,410,808; 3,733,390;
32 3,827,968 and patents mentioned therein.
33 ~eoause of their extremely hiqh 34 activity, these zeolite materials are deposited with a material possessiny a substantially lower level of cataly-36 tic activity such as a siliceous matrix material which may 37 be of the synthetic, semi-synthetic or natural type. The ,. ,~, ;.

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1 matrix materials may include silica-alumina, silica-gel, 2 silica-magnesia, alumina and clays such as mon~morillo-3 nite, kaolin, etc.
4 The zeolite which is preferably incorporated 5 into the matrix is usually exchanged with various cations 6 to reduce the alkali mekal oxide content thereof. In 7 general, the alkali matal oxide content of the zeolite 8 is reduced by ion exchange treatmen~ with solutions of 9 ammonium salt, or salts of metals in Groups II to VIII
10 of the Periodic Table or the rare earth metals. Examples 11 o~ suitable cations include hydrogen, ammonium, calcium, 12 magnesium, zinc, nickel, molybdenum and the rare earths 13 such as cerium, lanthanum, praseodymium, neodymium, and 14 mixtures thereof. The catalys~ will typically contain 15 2-25% of the zeolite component and 75-98% of the matrix 16 component. The zeolite will usually be exchanged with 17 sufficent cations to reduce the sodium level of the zeolite 18 to less than 5 wt. %, preferably less than 1 wt. %.
19 Other speci~ic examples of these types of catalysts are 20 found, for example, in U.S. Patent Nos. 3,140,249;
21 3,140,251; 3,140,252 and 3,140,253.
22 When u~ed in hydrotreating or hydrofining 23 reactions the catalyst component will contain a suitable 24 matrix component, such as those mentioned heretofore

25 and one or more hydrogenating components comprising the

26 transition metals, preferably selec~ed from Groups VI

27 and VIII of the Periodic Table. Examples of suitab:Le

28 hydrogenating metals which may be supported upon a

29 suitable matrix include, among others, nickel, coba:Lt,

30 moiybdenum, tungsten, platinum, and palladium, ruthenium,

31 rhenium, iridium (including the oxides and sulfides

32 thereof). Mixtures of any two or more of such hydrogenat-

33 ing components may also be employed. For example,

34 catalysts containing (1) nickel or cobalt, or the combina-tion thereofr in the form of metal, oxide, sul~ide, or 36 any combination thereof and (2) molybdenum or tungsten, - , ..
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1 or the combination thereof, in the form of metal, oxide, 2 sulfide or any combination thereof are known hydrofining 3 catalysts. The total amount of hydrogenating component sup-4 ported on the matrix may range from 2 to 25 wt.~, (calcu-5 lated as metal) usually 5 to 20 wt.~ based on the total 6 weight of the catalyst composition. A typical hydrofining 7 catalyst includes 3 to 8 wt.~ Co0 and/or NiO and about 8 to 8 20 wt.% MoO3 and~or WO3 (calculated as metal oxide).
9 Examples of reforming catalysts which may be 10 used in accordance with the invention are those catalysts 11 comprising a porous solid support and one or more metals 12 (or compounds thereof, e.g. oxides) such as platinum, 13 iridium, rhenium, palladium, etc. The support material 14 can be a natural or a synthetically produced inorganic 15 oxide or combination of inorganic oxides.
16 Typical acidic inorganic oxide supports which 17 can be used are the naturally occurring aluminum si].i-18 cates, particularly when acid treated to increase the 19 activity, and the synthetically produced cracking supports, 20 such as silica-alumina, silica-zirconia, silica~
21 alumina-magnesia/ and crystalline zeolitic aluminosili-22 cates. Generally, however, reforming processes are 23 preferably conducted in the presenca of catalysts having 24 low cracking activity, i.e., catalysts of limited 25 acidity. Hence, preferred carriers are inorganic oxides 26 such as magnesia and alumina. Other examples of suitable 27 reforming catalysts are found in U.S. Patent Nos.
28 3,415,737; 3,496,096; 3,537,~80; 3,487,00gi 3,578,583;
29 3,507,780; and 3,617,520.
Preferably, the particles which are fluidized 31 in the process of this invention will have a magnetiza-32 tion of at least 250 gauss, more preferably up to 3,000 33¦gauss, and will range in particle size of from 0.001 mm 341to ~0 mm, more preferably from 0.15 mm to 1.0 mm. Parti-

35 cle magnetization determines the stability of the bed and

36 sets the operable velocity range for particles of a .: .: , - , , ~ . . ~ ., . -.

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1 given particle size. Ferromagnetic content and applied 2 field are used to control particle magneti~ation. Parti~
3 cle magnetization is di~ficult to predict precisely 4 and magnetic measurements are generally made on particles 5 of different sizes and ferromagnetic content. Curves 6 of magnetization vs. applied field are obtained for 7 design purposes. Particles of dimensions greater than 8 50 mm will be difficult, of course, to fluidize, while 9 particles sma].ler than 0.001 mm will be difficult to 10 contain in any fluidized process. In addition, the 11 larger the magnetization of the particles, the higher 12 will be the transition velocity up to which the fluidized 13 bed may be operated without bubbling, all other factors 14 held constant.
The magnetizable catalyst particles of the 16 invention will contain 1 to 75, usually 5 to 50, wt.~
17 (based on total weight of the particle) of the afore-18 described magnetic material and may be prepared by 19 conventional techniques, such as by impregnating the 20 aforedescribed zeolitic and/or inorganic oxide catalytic 21 materials with a soluble precursor of a ferromagnetic Z2 substance which is subsequently reduced or oxidized to 23 render the particles ferromagnetic. Alternativaly, the 24 ferromagnetic material may be incorporated into the 25 catalyst component by encapsulation of finely divided 26 ferromagnetic material.
2~ The particulate solids mixture of the invention 28 may comprise various amounts of the heat carrier particles 29 and the magnetizable catalyst particles. ~n general, the 30 particulate solids mixture will contain 1 to 15, prefer-31 ably 1 to 10, volume % of the heat carriar particles 32 and 85 to 99, preferably 90 to 99 volume % of the magne-33 tizable catalyst particles.
34 The particulate solids mixture employing the 35 magnetizable substantially non-catalytic particles and 36 non-magnetizable catalytic particles contains from

37 about 1 to 75, preferably 5 to 50 volume % of the . :
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l substantially 25 to 99, preferably 50 to 99~ by volume of 2 the non-magnetizable catalyst particles.
3 The size and density of the heat carrier parti-4 cles and the catalyst particles are chosen so that the heat carrier particles may be separated from the catalyst 6 particles by gravity settling in separation zones commu-7 nicating with the reactor and regenerator zones~ Accord-8 ingly, the heat carrier particles will have a significantly 9 higher settling rate than the catalytic particles since the heat carrier particles will be heavier and/or larger 11 than the catalyst particles. The relative density and 12 size of the heat carrier and catalyst particles will be 13 such that settling velocities of the inert heat carrier 14 will range between 0.04 and .4 ft./sec. The settling rate for the heat carrier is a function of the heat 16 carrier concentration and the effective ~iscosity of the 17 catalyst bed. The settling rate can be determined 18 experimentally for the particular reaction system em-19 ployed. Data generally follow Stokes' law and can be estimated using the effective ~iscosity of the bed and 21 particle size. Typical data on 2.2 gm/cc beads in 22 alumni are shown in Figure l.
23 Heat carrier concentration also ~aries wlth 24 bed height and can be determined using the following relationship: Wb e -VY/D + Wt 26 c = V V

28 where: c = heat carrier concentration, lbst/cu, ft.
29 V = settling rate, ft./sec.
Wt= rate heat carrier is fed in at the top, lbs.
31 (sec. x s~. ft.) 32 Wb= rate heat carrier is picked up from the ~ot 33 tom, lbs./ (sec. x sq. ft.) 34 D = diffusion coefficient of the bed, ft.2/sec.
Y = height above heat carrier-catalyst interface 36 (e.g. I of Figure 21, ft.
37 Typical concentration profiles calculated using .. - ;
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1 this equation show large concentrations near the bottom 2 of the bed. This is due to the first term in the equa-3 tion. At large values of bed height concentration 4 becomes constant and equals Wt/V.
The op~rating conditions to be employed in the 6 practice of the present invention are well known and will, 7 of course, vary with the particular conversion reaction 8 desired. The ~ollowing table summarizes typical reactor 9 conditions effective in the present invention.

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1 The feedstocks suitable for conversion in ac-2 cordance with the invention include any of the well-3 known feeds conventionally employed in hydrocarbon con-4 version processes. Usually, they will be petroleum de-rived, although other sources such as shale oil and coal 6 are not to be excluded. Typical of such feeds are heavy 7 and light virgin gas oils, heavy and light virgin naph-8 thas, solvent extracted gas oils, coker gas oils, steam-g cracked gas oils, middle distillates, steam-cracked naphthas, coker naphthas, cycle oils, deasphalted residua, 11 etc.
12 The heat carrier particles and the catalyst 13 particles which are separated in the reactor and regen 14 erator separation zones, or in a separate separation zone, are independently circulated through the system. In 16 order to compensate for heat efects in the reactor and 17 the regenerator, the heat carrier particles are recycled 18 at a rate to keep the system heat balance. Heat exchan-19 gers are employed to add or withdraw heat to or from the heat carrier particles circulated between the reactor 21 and regenerator.
22 The application of a ma~netic field to the 23 reactor, or the reactor and the catalyst regenerator in 24 accordance with the invention is not to be limited to any specific method of producing the magnetic field.
26 Conventional permanent magnets and/or electromagnets 27 can be employed to provide the magnetic field used in the 28 practice of this invention. The positioning of the mag-29 nets will, of course, vary with the solids used, degree of fluidization required and the effects desired. In 31 the preferred embodiment of this invention, a toroidally 32 shaped electromagnet is employed to surround at least 33 a portion of the fluidized bed of the reactor, or the 34 reactor and the catalyst regenerator, as this provides those skilled in the art with an excellent method of 36 achieving near uniform magnetic force and stability 37 throughout a bed. Such electromagnets when powered by ` : ., , , . ' ' `' -14- ~5g~

1 direct current with the use of a rheostat are particu-2 larly desirable for applying a magnetic field to the bed 3 particles and to provide an excellent method of stabili-4 zing the fluidization of the bed particles in response to changing flow rates of the fluidizing medium.
6 - The invention is not limited by the shape or 7 positioning of the magnet employed ~o produce the magne-~ tic field~ The magnet can be of any size, strength or 9 shape and can be placed above or below the bed to achieve special effect. The magnets employed in this invention 11 can be placed within or without the vessel and may even 12 be employed as an integral portion of the vessel structure 13 its~lf. The process is not limited to any particular 14 vessel material and it can be readily adopted for use in reactors currently employed by industry.
16 The degree of magnetic field to be applied to 17 the fluidized solids in the reaction zone will, of 18 course, depend on the desired magnetization for the 19 ferromagnetic particles and the amount of stabilization desired. Particulate solids having weak ferromagnetic 21 properties, e.g. cobal~, nickel, etc. will require the 22 application of a stronger magnetic field than particulate 23 solids having strong ferromagnetic properties, e.g., 24 iron, to achie~e similar stabilization effects. The size and shape of the solids will obviously have an efect on 26 the strength of the magnetic field to be employed.
27 However, since the strength of the field produced by an Z8 electromagnet can be finely adjusted by adjusting the 29 field strength of the electromagnet, an operator can readily adjust the field strength employed to achieve 31 the desired degree of stabilization for the particular 32 system employed. Specific methods of applying the 33 magnetic field are also described in U.S. Patents 34 3,440,731 and 3,439,899 and ~elgian Patent 834,384 37 Figures 2 and 3 are diagrammatic flow plans ." : ' ' . ' ~ ..

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1 illustrating specific embodiments of the first embodi-2 ment invention.
3 Figure 4 is a diagramatic flow plan illustrating 4 a second embodiment of the invention.
PREFERRED EMBODIMENTS OF THE INVENTION
_ 6 Referring to Figure 2, a naphtha feed boiling in 7 the range of 200-375F., hydrogen recycle gas, ferromag-8 netic catalyst particles and ferromagnetic substantially 9 inert heat carrier particles are introducing into reform-ing reactor 1 via lines 11, 12, 13, and 14, respectively~
11 Reactor 1 is surrounded by electromagnetic coil 2 which 12 is powered by a direct current source (not shown). Elec-13 tromagnetic coil 2 is arranged to apply a substantially 14 uniform field on the particle solids charge in reactor 1.
In this particular example, electromagnetic coil 2 pro-16 vides a uniform magnetic field of 500 Oersteds.
17 The ferromagnetic heat carrier particles are 18 stainless steel (~00 series) particles having a particle 19 si%e in the range of 400-800 microns. The ferromagnetic catalyst which is introduced into reactor 1 via line 13 21 is a commercially available reforming catalyst which has 22 been combined with 6 wt.% of stainless steel (400 series) 23 by encapsulation of the stainless steel with the alumina 24 base. The reforming catalyst contains 10 wt.% Mo03 on an alumina basa ~wt.% excludes weight of fexromagnetic 26 material).
27 Settling zone 3 is connected to reactor 1 for 28 separation of the heat carrier and catalyst particles.
29 Recycle gas furnished through line 12 is introduced into reactor 1 via settling zone 3.
31 The heat carrier particles are coarse and have 32 a higher density than the catalyst particles. Depending 33 upon the heat carrier circulation rate and settlingvelo-3~ city, a concentration gradient is established from the top level (designated L) of reactor 1 to the interface 36 (designated I) in settling zone 3. Thus, the concentra-37 tion of the heat carrier solids is virtually O at L and . .

9~V~39 1 virtually 100% at I. The heat carrier particles which 2 settle out in settling zone 3 are withdrawn therefrom by 3 means of line 17 which delivers the heat carrier particles 4 to heat exchange zone 8 for removal of heat as desired from the system prior to transfer to regenerator 5 by 6 means of line 18. The spent ferromagnetic reforming 7 catalyst is removed from reactor 1 via line 15 for deli-8 very to regenerator 5. The upgraded naphtha product from 9 reactor 1 is withdrawn from line 16. The lines for trans-ferring the various streams are equipped with valves (not 11 shown) to regulate the flow to a desirable level.
12 The spent catalyst from reactor 1 is regenerated 13 in regenerator 5 by contacting the spent catalyst with 1~ air introduced via line 19 at a temperature of about 1125F. Regenerator 5 is connected to settling zone 7 16 for removal of the heat carrier particles as in the 17 a~oredescribed reactor settling zone system. Stripping 18 gas is introduced into settler 7 via line 20. Regenera-19 tor 5 is surrounded by electromagnetic coil 6 which is 20 arranged to apply a substantially uniform field on the ~1 particulate solid charge therein. The electromagnetic 22 field to be applied to regenerator 5 is 500 Oersteds.
23 The physical operation in the regenerator-settling zone 24 system parallels that of the reactor-settling zone system 25 with the concentration gradient for the heat carrier 26 particles varying from virtually O at L' to virtually 27 100% at I'. The heat carrier particles which separate 28 from settling zone 7 are delivered via line 21 to heat 29 exchange zone 4 wherein heat may be added and the parti-30 cles thereafter transferred by means of line 14 to 31 reactor 1. The regenerated catalyst particles are 32 removed from regenerator 5 by means of line 13 for deli-33 very to reactor 1. The flue gas from regenerator 5 exists 34 via line 22.
The operating conditions and yields for the 36 aforedescribed process scheme are shown in Table 1 below.
37 Various modifications may be made to the process ' :
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1 flow plan depicted in Figure 2. For ~xample, admix-2 tures of heat carrier and catalyst particles could be 3 circulated between reactor 1 and regenerator 5 by joining 4 line 15 with line 17 prior to heat exchanger 8 and by joining line 13 with line 21 prior to heat exchanger 4.
6 A further modification of the process flow plan 7 of Figure 2 is shown in Figure 3 wherein the ratio of 8 heat carrier and catalyst circulated together in the 9 transfer lines connecting reactor 1 and regenerator 5 is controlled by withdrawing the admixture above the heat 11 carrier interfaces I and I'. As shown in Figure 3, trans-12 fer lines 17 and 21 extend into settling zones 3 and 13 7, respecticely. Since the concentration of heat carrier 14 solids is virtually O at L and L' and virtually 100% at I and I', the position above interfaces I and Il is ad-16 justed so that the proper ratio of heat carrier and cata-17 lyst required for heat balance is obtained.

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3 Feed: 200 -375F. Naphtha 4 Reactor Conditions 5 Temperature, F. 900 6 Pressure, psig 200 7 Feed Rate, W/Hr./W 0.45 8 Reactor Catalyst Holding Time, Mrs. 2.0 9 Reactor Velocity Above Feed Inlet, 10 ft./sec. 0.30-0.60 11 Reactor Stripper Velocity, ft./sec. 0.88 12 Catalyst Oil Ratio 1.0 13 Heat Carrier/Catalyst Ratio 2.0-4.0 14 Recycle Gas, SCF/B 4500 15 H2/Oil Ratio 3.0 16 Ractor Yields 17 Res. ON 85-95 18 Vol.% C5+ 80.4 19 Vol.~ C4+ 4.1 20 Wt.~ C3 21 Wt.% Carbon 0 3 22 Particulate Solids 23 Heat Carrier Density, lb./ft. 195 24 Heat Carrier Particle, Microns 400-800 25 Heat Carrier, Wt.% Ferromagnetic 50 26 Catalyst Density, lb./ft.3 69-78 27 Catalyst Particle Size, microns 70-250 28 Catalyst Wt.% Ferromagnetic 6 29 Regenerator Conditions 30 Temperature, F. 1125 31 Pressure, psig 200 32 Regenerator Velocity, ft./sec. 0.35-0.60 33 Referring to Figure 4, a light Arabian gas oil 34 feed, ferromagnetic non~catalytic particles, and non-magnetic catalytic particles are introduced into the 36 reaction zone of cat cracker reactor 101 via lines 110, 37 112, and 114, respectively. Reactor 101 is surrounded ~ i3~

1 by electromagnetic coil 102 which is powered by a direct 2 current source (now shown). Electromagnetic coil 102 3 is arranged to apply a substantially uniform field on 4 the total particulate solids charge in reactor 101. In this particular example, electromagnetic coil 102 gives 6 a uniform magnetic field of 350 Oersteds~
7 The ferromagnet'ic, non-catalytic particles 8 employed in reactor 101 are stainless steel particles 9 consisting o~ stainless steel (400 series). The catalyst which is introduced into reactor 101 via line 114 is a 11 conventional cracking catalyst which is a rare earth 12 exchanged y-type zeolite containing about 4.0 wt.% Re203 13 and sold under the trade name CBZ-l.
14 The hydrocarbon conversion products from ~eactor 101 are withdrawn via line 118 and later condensed and 16 distilled for separation into various products. The 17 spent catalytic particles and the ferromagnetic particles 18 are withdrawn from reactor 101 via line 116 and sent to 19 separation zone 103 where the catalyst and ferromagnetic particles are separated by elutriation using steam to 21 carry the light catalyst particles overhead and to per-22 mit the heavier stainless steel heat carrier particles to 23 settle out. The separated catalytic particles are with-24 drawn from separation zone 103 via line 120 and intro-duced into the regeneration zone of regenerator 104 26 wherein the spent catalyst is conventionally regenerated 27 by burning the coke deposited thexeon in the presence of 28 air which is introduced into regenerator 104 by means of 29 line 124. Flue gas and regenerated catalyst from regen-erator 104 exit via lines 126 and 114, respectivelyO The 31 ferromagnetic solids from separation zone 103 are with-32 drawn by line 122 for introduction into heat exchange 33 zone 105 wherein the ferromagnetic particles are in heat 34 exchange contact with the hot flue gas (about 800-1400F.) introduced into heat exchange zone 105 by line 126. The 36 flue gas exits from heat exchange zone 105 via line 128.
37 The ferromagnetic particles which have been heated by . .
.

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1 contact with the hot flue gas are removed from heat 2 exchange zone 105 via line 114 for delivery to reactor 3 101.
4 The operating conditions and yields for the aforedescribed process scheme are shown in Table II
6 below.
7 Table II
8 Conditions and Yields for Catalytic Cracking Operation 9 Reactor Conditions Temperature 950F
11 Pressure 35 psig 12 Feed Rate, W/H/W 40 13 Catalyst/Oil, Weight Ratio 4-3 14 Vol.~ Ferromagnetic Particles 20 Vol.% Catalyst Particles 80 16 Catalyst Particle Size 50-100 Microns 17 Ferromagnetic Particle Size 20-30 Microns 18 Velocity 2 Ft./Sec.
19 Applied Field 360 Oersteds Ferromzgnetic Particles/Oil, 21 Weight Ratio 7.0 22 Regenerator Conditions 23 Temperature 1205F.
24 Pressure 35 pslg 25 Air Rate 140 Kilo SCFM
26 Reactor Yields 27 H2S, Wt. % 1.2 28 Cl/C2' Wt.% 2.~
29 C3, Vol. % 7.4 C4, Vol. % 13.1 31 C5/430, Vol. ~ 55.~
32 430/650, Vol. % 22.1 33 750+, Vol. % g.8 34 Coke, Wt. % 4.7 35 Example 36 Another operation that can be carried out in the 37 system of the present invention is catalytic reforming .

-21~ a~

1 using process steps similar to those described above with 2 reference to Figure 4, but with different specific pro-3 cess conditons. Conditions for processing a 160/350F.
4 light Arabian naphtha with a reforming catalyst contain-ing 0.3 wt.% Pt and 0.3 wt.% Re on an alumina base are 6 given below in Table III.

g Severity 100~ RON Clear 10 Recycle Gas Rate 4000 SCF/B
11 Reactor Conditions 12 Temperature, F. 915-962 13 Pressure, psig 210 14 Solids Circulation: Kilo l~./hr.
15 Catalyst Particles ! 8.62 16 Ferromagnetic Particles 6.38 17 Velocity, E't./Sec. 1.3-1.7 18 Particle Size, Microns 19 Catalyst Particles 50-100 20 Ferromagnetic Particles 20-50 21 Applied Field, Oersteds 500 22 Reactor Yields _ _ 23 ~2 2.7 Wt.%
24 Cl 1.4 Wt.
25 C2 2.7 Wt.
26 c3 3.3 Wt.~
27 iC4 1.~ Wt.%
28 nC4 2.7 Wt.%
29 C5~ 85~4 Wt.%

. ,, . -. .
' ~ i , ' , ' , ' :~ `~

Claims (10)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A hydrocarbon conversion process which com-prises (a) contacting a hydrocarbon feedstock in a conversion zone having a magnetic field applied thereto with a fluidizable particulate solids mixture containing a plurality of separate discrete substantially inert heat carrier particles and magnetizable catalyst parti-cles, said substantially inert heat carrier particles having settling rates higher than the settling rates of said catalyst particles; (b) permitting said heat carrier particles to settle in preference to the catalyst parti-cles in a settling zone communicating with said conver-sion zone; (c) circulating said catalyst particles from the conversion zone to a regeneration zone having a mag-netic field applied thereto; (d) circulating said heat carrier particles from the settling zone to said regene-ration zone, said circulation of heat carrier particles being independent of the circulation of catalyst particles;
(e) contacting said catalyst particles in the presence of said heat carrier particles with oxygen at elevated temperatures to burn coke deposited upon said catalyst particles; (f) permitting said heat carrier particles to settle in preference to the catalyst particles in a set-tling zone communicating with said regeneration zone;
(g) circulating said catalyst particles from the regenera tion zone to a conversion zone having a magnetic field applied thereto; and (h) circulating said heat carrier particles from the settling zone to said reaction zone, said circulation of heat carrier particles being indepen-dent of the circulation of catalyst particles.

2. The process of claim 1 wherein said heat carrier particles are magnetizable.

3. The process of claim 1 wherein the heat carrier particles from the settling zone in step (d) are circulated to a heat exchanger means prior to transfer to the regeneration zone, and wherein the heat carrier particles from the settling zone in step (g) are circu-lated to a heat exchanger means prior to transfer to the reactor zone.

4. The process of claims 1, 2, or 3 wherein said magnetic fields are uniform and oriented substantially axially to the flow of fluid in said reactor zone.

5. The process of Claim 1 wherein the heat car-rier particles and said catalyst particles from the set-tling zone of step (c) are circulated to a regeneration zone having a magnetic field applied thereto; and therein (d) contacting said catalyst particles in the presence of said heat carrier particles with oxygen at elevated tem-peratures to burn coke deposited upon said catalyst par-ticles; (e) permitting said heat carrier particles to settle in preference to the catalyst particles in a set-tling zone communicating with said regeneration zone; and (f) circulating said heat carrier particles and said cata-lysts particles from the regeneration zone to a conversion zone having a magnetic field applied thereto.

6. The process of claim 5 wherein said heat car-rier particles are magnetizable, and wherein the heat car-rier particles and catalyst particles from the settling zone in step (c) are circulated to a heat exchanger means prior to transfer to the regeneration zone and wherein the heat carrier particles and catalyst particles from the settling zone in step (f) are circulated to a heat exchanger means prior to transfer to the reaction zone.

7. In a hydrocarbon conversion process wherein fluidizable particulate catalyst solids are circulated between a fluidized bed reaction zone in which said par-ticulate catalyst solids are contacted with a hydrocarbon feedstock resulting in the deposition of coke on said catalyst solids and fluidized bed regeneration zone in which catalyst particles having coke deposited thereon are contacted with an oxygen-containing gas to remove said coke coke by combustion, the improvement which comprises (a) introducing into said reaction zone particulate solids having ferromagnetic properties to that said hydrocarbon feedstock is contacted with a particulate solids mixture containing a plurality of separate, discrete (1) magne-tizable substantially non-catalytic particles, and (2) non-magnetizable catalytic particles (b) applying a magnetic field to said reaction zone to form a magneti-cally stabilized fluid bed in said reaction zone; (c) with-drawing said particulate solids mixture from the reaction zone; (d) separating said magnetizable substantially non-catalytic particles from said non-magnetizable catalytic particles; and introducing said non-magnetizable catalytic particles into said regeneration zone.

8. In the hydrocarbon conversion process of claim 7, the improvement comprising circulating said mag-netizable particles to a heat exchange means, and con-tacting said magnetizable solids with the combustion gases from said regeneration zone to heat said magnetizable solids and thereafter introducing said heated magnetizable solids into said fluidized bed reaction zone.

9. An apparatus comprising:
(a) a vessel for containing a fluidized solids bed;
(b) means for applying a magnetic field to said vessel;
(c) a bed disposed within said vessel and con-taining a particulate solids mixture of (1) magnetizable substantially non-catalytic particles, and (2) non-magnetizable cataly-tic particles;
(d) means for fluidizing said bed;
(e) means for withdrawing said particulate solids mixture from said vessel; and (f) means for separating said magnetizable sub-stantially non-catalytic particles from said non-magnetizable catalytic particles.

10. The apparatus of claim 9 comprising means for exchanging heat with said separated magnetizable sub-stantially non-catalytic particles.