Патент USA US2412696код для вставки
.1. R. SCHQNBERG Erm. 2,412,649@ PROCESS FOR REGENERATION OF CRACKING CATALYSTS Filed « Oct. 23 , 1940 î? m @WHM M w 2 Shèets-Sheeíh 1 Patented Dec. 17, 1946 2,412,696 . VUNITED STATES' PATENT oFFlc PROCESS 'FÜR REGENERATION OF . CRACKING CATALYSTS Jackson R. Schonberg, Westfield, and Donald L. Campbell, Roselle Park, N. J., asslgnors to Standard Oil Development Company, a corpo ration of Delaware Applicatlon October 23, 1940, Serial No. 362,380 r‘ ` ` f" , "’ 2 claims» (ol. cs2-_242) 1 . 2 The present invention relates to improvements advantage of this process is that it requires a in the art of reactivating or regenerating solid large combustion chamber to provide the neces divided catalytic materials containing carbona sary time of contact due to the large volume of ceous contaminants by means of combustion of total gases required, This _known process also the catalyst contaminants under closely con 5 requires large and expensive equipment. to sepa trolled conditions. 'I'he catalyst may be an acid rate the regenerated catalyst from the gases leav-` treated clay, silica gel, or a plural gel, such as ing the combustion chamber. silica-alumina gel or alumina-silica «compositions» The main object of our invention is to regen in powder form and its regeneration may be of erate a fouled catalyst, suspended in a regenera the type wherein the catalyst is' suspended in an 10 tion gas, to remove the suspension after regenera oxygen containing gas during regeneration. The tion of `the catalyst from the regeneration zone, catalyst contamination may be due to its sus and to return a portion -of the regenerated cat pension in high boiling hydrocarbons under alyst from said removed suspension, after cool cracking conditions. ing, to one or more points in said regeneration It is, of course, well known that when an acid 15 zone in order to control the temperature of the treated clay is contacted with a hydrocarbon oil under suitable conditions of temperature, pres Other and further objects of our invention will sure, time and intimacy of contact, as for ex appear from the following more detailed descrip ample, where a gas oil is cracked in the presence tion. of an acid-treated clay, the process results in the 20 These objects may be carried out by the process progressive deposition of carbonaceous materials < and apparatus hereinafter fully described‘in con-upon the catalyst. These contaminants impair junction With the accompanying drawings form regeneration. the activity of the catalyst and necessitate the ’ removal from the conversion operation, of the ' ‘ " . ing part of this Specilication. ' ‘ In the accompanying drawings, Fig. 1 shows a catalyst after it has accumulated about l/3% to 25 combination of apparatus elements diagrammati 5% by weight of contaminants for reviviñ'cation cally and in partial vertical section, in which cat or regeneration and as indicated, the most satis. factory regenerationv method is one in which the contaminants are removed by combustion of the latter. alyst may be suspended in a regeneration gas. . . conducted to a regeneration chamber, removed from said regeneration chamber, separated from 30 the gaseous constituents and returned in part' Our present invention Ais concerned with. the.` , after cooling to the regeneration zone to aid in regeneration of a solid spentcatalyst by burning - or oxidizing the contaminants under closely con trolled conditions of time of contact of catalyst . and regeneration gas; also of temperature, pres controlling the temperatures therein prevailing, l and in Fig. 2, which is a modiñcation of the proc essl illustrated by Fig. 1, means `are provided 35 for returning the cooled regenerated catalyst to. sure, and intimacy of mixing and handling of the , the regeneration zone at a plurality of spaced catalyst, so as to prevent overheating or baking of the catalyst, or otherwise injuring its activity. It is generally known in the art that a‘ catalyst such as an adsorbent clay -catalyst cannot be sub jected for a considerable length of time to a tem apart points. - Our invention will now be more specifically de- Í scribed in its embodiment shown in accompany- ‘ 40 ing Fig. 1. Referring in detail to the drawings, s the reference character I designates a hopper perature above 1100° F., certainly not above 1200° containing a, powdered catalyst to be regenerated. F., without permanently injuring the catalyst. It This material may comprise, for example, natu is also known that catalysts of the type indi rally active or activated adsorbent clays or syn cated can be regenerated without injury by using 45 thetic adsorbent materials of the same or differ air strongly diluted with inert or non-oxidizing ent composition._ The catalyst, we may assume, , gases. This can be vdone by .suspending the fouled is contaminated with carbonaceous deposits asa catalyst in a mixture of the air and other gases result of contact with hydrocarbon vapors during at a temperature just above that at ,which com an oil cracking operation. W bustion proceeds with reasonable rapidity, and 50 Prior to regeneration of the catalyst materiahn the presence of the diluting gases insures that it may be purged to remove volatile hydrocar the heat generated by the combustion will not bons. There are many known' methods of purg- , raise the catalyst temperature and the resulting ing or stripping the catalyst. Most of them in-l mixture of gases above a temperature at which volve causing the catalyst to ñow ‘countercurrent` injury to the catalyst ensues. However, one dis 55 against a gas, such as steam heated to approxi-,5~v 2,412,696 3 mately the> temperature of the catalyst itself. The catalyst material still at an elevated tem-. perature, approximately that of the outlet of the cracking reactor is continuously withdrawn from the> hopper I by means of a feeding mechanism, such las a star feeder 2, and discharged into a suitable transfer mechanism, such as a screw con veyor 3, and by means of the latter discharged into a chamber or chest 4.l Air or other free-oxygen-containing regener ation gas at atmospheric ltemperature is drawn through line 5 into blower 6, discharged to lines 1 and 8, through a suitable regulating valve in line 8, and into said chest 'at point 9. Within ’said chest a suspension, of the catalyst in the 15 regeneration gas is formed. From chest 4 the suspension is withdrawn through line I0, thence ' y t it is withdrawn through line 2I to conveyor 22, which may be similar to conveyor 3, above de scribed. The conveyor l22 discharges the said catalyst into chest 25 where it is suspended inl compressed air supplied by blowers 6 through lines 'l and 24 and a suitable control valve in the latter‘line, the air being discharged into the chest at point 23. The suspension is withdrawn through line 26 and forced through heat ex changer 21 where it is cooled by a cooling medium introduced through line 28 vand withdrawn through line 29. The cooled, suspended cata lyst is withdrawn from the heat exchanger 21 through line 3l) and mixed with the suspension of fouled catalyst, leaving line I0, in line II as previously stated. . The portion ofthe suspension in line I6 from which it is not desired to remove catalyst for return to the chamber is withdrawn through a in air or other free-oxygen-containing gas in 20 regulating valve and admixed with the gas recov ered from separator I8 and both are discharged a manner which will be presently fully described, into an initial cyclonel separator 32 where the bulk and the confluent suspensions are discharged into of the catalyst is separated from thegas. The a, regeneration chamber I2 through means pro catalyst so separated drops to the bottom of vided to agitatoy the contents of said chamber. said cyclone separator and is discharged into con 25 This latter means may consist of an inlet mani. duit 33 through star feeder 34 into a stripping fold discharging through a number of pipes I3 discharged into linel I I containing a suspension of cooled, recently regenerated catalyst suspended chamber-35, wherein it passes downwardly in countercurrent flow against an upflowing strip ber, each pipe discharging through a number of ping gas, such. as steam CO2, flue gas, etc., intro perforations or nozzles I4, directing iiow hori zontally into the chamber. Similarly the sus 30 duced into the stripping chamber through line 36. The stripping chamber 35 is preferably provided pension may be withdrawn from the chamber with a plurality of baflies such as inverted cone through a like arrangement of nozzles and mani and slanted peripheral bailles 31 to insure inti fold pipes I5 adapted to receive and Aconduct the mate contact between the catalyst and the strip suspension downwardly and out of the chamber 35 -ping gas. The strippingv or purging gas serves I2 through line I6. to remove oxygen containing gases from the The use of the --above mentioned pipes and catalyst. The stripping gas introduced into the nozzles causes the contents of the regeneration stripping chamber 35 passes upwardly there chamber to be thoroughly agitated, and inter through and is discharged therefrom through line mixed. The injected suspension of catalyst is 48 into line I6 as shown, where it admixes with 40 heated by contact with the contents of the cham the suspension therein and is thereafter proc ber to the temperature of combustion of the essed with the latter. ` catalyst contaminants which is proceeding in the The powder, after being purged of regenerating chamber. Therefore, the catalyst throughout its gases in the stripping chamber 35, is collected time of residence in the chamber is at a con siderably higher average temperature than it 45 in the bottom thereof and may be removed there from to conduit 38vcarrying a suitable pressure would be >if it passed, let us say, lengthwise seal such as a star feeder 38. The regenerated through a long narrow chamber in which there catalyst is preferably passed directly to a con ' was-no agitation ofthe contents and little, if any, version unit, e. g., a cracking unit (not shown) heat transfer from the catalyst already resident while still at elevated temperature so that the» :Y1 for sometime in the chamber to that portion of heat of -regeneration can be Autilized in carrying `-catalyst at its moment of entry. The above extending vertically downward into the cham Vmentioned agitation permits cooling either the . suspension of spent catalyst or the suspension of out the conversion treatment. ` , Gas from the cyclone separator 32, having th bulk of the powdered catalyst removed there- v ' recycled recently regenerated catalyst or both to a relatively low> temperature while- still obtaining 55 from, but still containing a substantial amount of powdered material, is removed from the cyclone relatively rapid combustion in the regeneration separator 32 through line 40 leading to a sec chamber. This cooling of the suspensions to ond cyclone separator 4I wherein further -powder loW temperatures> is of advantage in reducing is removed from the regenerating gases.~ Regen the rate of catalyst recycling required in order to provide suflicient cooling in the regeneration 60 erated powder separated in lthe second cyclone separator 4I drops to .the bottom thereof and chamber. Also with all of the catalyst in the may be removed to line 42 and introduced into regeneration chamber being oxidized at a rela the top of thestripping chamber 35 wherein it tively high temperature rather than at a tem- . perature rising gradually from a relatively low~ is stripped of regenerating gases in the same , inlet temperature to a higher outlet temperature, 65 manner as the catalyst from the initial cyclone the rate of `oxidation is increased and the size A of the regeneration chamber required is corre- » ' separator 32. The conduit 42 is preferablypro vided with a suitable pressure seal such as a star y feeder 43 to prevent the stripping gases from passing upwardly into the second cyclone sepa A portion’of the suspension is withdrawn from line I6 through line I1 anda suitable regulating 70 rator. The gases, after passing through the sec ond cyclone separator 4I, are removed there valve and discharged into cycloneseparator I8. . .from through line 44 leading to a third cyclone The major portion 'of the lcatalyst contained in spondingly reduced. separator 45 for removal of the remainder ,ofl the said portion ofthe suspension is separated from the regeneration gas in said separator -and ' the catalyst from the regenerating gases. ‘Cata is removed through line I8 into hopper 2li, thence 75 lyst separated in the third cyclone separator 45 is 2,412,696 f 5 discharged into .the stripping chamber 35 through line 4I, provided with a star feeder 41. 'I'he regenerating gases, after passing through the third cyclone separator 45, are substantially tree of powdered catalyst. The gases are removed from` the .third cyclone separator 45 through line 49, _and may be rejected from the system through The modiñcatlon shownin Fig. 2 has regard to the form and construction of »the regenera-` tion vessel and the means forÁ supplying regen erated catalyst and spent catalyst to the said re generation chamber. That is to say, the catalyst is suspended in this modiñcation in exactly the same manner as in the modification shown in a pressure relief valve 50 adapted to impose the Fig. 1, thence »thev suspended catalyst is discharged desired back pressure on the system. into line I0a and thereafter passed into the bot tom of an elongated regeneration chamber |2d. It will be understood that 'the apparatus de scribed may be modiiled in many ways known to those skilled in the art. For example, the means used for conveying the catalyst from `hopper I,> into the chest 4 may comprise a‘lock hopper sys tem such as was shown in the prior application of Donald L Campbell, Serial No. 311,477, filed De cember 29, 1939, with suitable alterations to Der mit operating‘the uppermost compartment un der low pressure and the lowermost compartment In the illustration shown we may consider that the regeneration. chamber I2a contains four zones viz. -zones 8|, 82, 83 and 84. Hot regener ated catalyst is withdrawn from a `hopper 90, discharged into a screw conveyor 92, (shown only in end View) thence into a chest 98, where it is dispersed in air discharged into the chest through valve line |00. The dispersion of hot regenerated catalyst in air is then withdrawn from the chest ' under high pressure, or may consist of some other 20 98 through conduit |04, thence 4passed through a cooler |06, Where a portion of the sensible heat device for conveying the fouled catalyst continu of the catalyst is removed by heat transfer to a ously against the pressure differential. Similar cooling medium such as water, with which it ly, conveyors 3 andI 22 may be replaced by some comes in indirect heat transfer relationship. The other device for accomplishing the same purpose. cooled catalyst is then withdrawn from the cooler Also, the means for injecting the regenerating 25 through conduit |08 and discharged into the suspension` through line I I into regeneration uppermost portion of the zone represented" chamber I2 may be varied. For exam-ple, the sus by the reference character 83. In `like man pension may be injected through a Venturi mixer ner, catalyst from hopper 90 is discharged into into which the contents of the regeneration cham screw conveyor I|2, thence into chest II4 where ber are drawn for the purpose of agitation with 30 it is dispersed in air discharged into the chest the incoming suspension, or, as another alter through line ||6. Thereafter the catalyst is with native, the contents of the chamber may be agi drawn through line |I'I, discharged into a cooler tated by means oi’ a multi-bladed ian as dis closed in the prior application oi’ Donald L. Camp bell, Serial No. 234,555, now U. S. Patent 2,282,453, iiled _November l2, 1938. |»|9, similar to cooler |06, and thence discharged ‘ through line |20 into the uppermost portion of zone 82. Finally, the catalyst in hopper 90 is discharged into screw conveyor |21, thence dis Further, .the means for removing from the sus charged into mixing chest II9 where it is dis pension leaving the regeneration chamber, the persed in air discharged into the chest through portion of the catalyst which it is desired to re 40 line 6|, thence withdrawn through conduit |28, ' turn to the regeneration chamber may be varied. . thence discharged into cooler |30, and then forced For example, all of the suspension leaving the chamber may be Withdrawn through a single cy clone separator from which part of the separated catalyst is returned to the regeneration chamber and-part withdrawn through suitable apparatus Ior further use in cracking. Also, other means may be employed, such as electrical precipitators, to remove the catalyst- from the suspension.Y The heat exchanger 21 may Ibe a boiler water i’eed preheater or a waste-heat boiler, or a pre heater for the feed to the catalytic unit. ` into zone 8|. The spent catalyst passing up- ` ` wardly through the regeneration vessel is periodi cally contacted with cooled regenerated catalyst in the manner‘shown. The catalyst enters the zones 8 I, 82, 83, and 84 at the minimum tempera ture at which reasonably rapid combustion can be obtained, say a temperature of 850° F. or there ’abouts, and leaves the several zones at the maxi mum permissible temperature that will not cause be varied to suit a number of conditions, such as impairment or‘destructîon of the catalyst. The hot catalyst undergoing regeneration is- cooled by the cooled regeneration catalyst from the maximum temperature to the minimum tempera ture at which reasonable rapid combustion may the kind and character of the catalyst, the tem take place. Also, the amount of oxygen in line It will, of course, be understood that the oper ating conditions prevailing in chamber I2 should perature which it can stand without injury, the amount and character of the contaminants on the catalyst, and the'- degree ~to which these are to be removed to make the catalyst suitable for further use, and other factors. However, gener ally speaking we may say that the following con ditions in the chamber give good results: Pressure from 1 to 30 atmospheres absolute. Temperature of mixed suspensions entering re generation or combustion vessel from atmos pheric to 950° F. Temperature of suspension leaving combustion ' vessel from 1000 to 1l00° F. I0a is so regulated as to be substantially all con sumed at the point where further quantities of oxygen is added together with cooled catalyst through line , |3I. Similarly, the'oxygen added through this line |3I is consumed, or substan tially consumed, when a further quantity of oxygen is added through line |20, and the oxygen added through line |20 is consumed through combustion by the time the gases have attained the level where the suspension of catalyst in oxygen or air is added through line |08. The sus pension of catalyst is eventually withdrawn through line |6--a from the top of the regenera chamber, and it may be recovered :from the Ratio oi' recycled catalyst torcontaminated cata 70 tion flue gases by passing it through one or- more lyst by weight from 0.5:1 to 6: 1. ì ' , , Air or equivalent oxygen-containing gas used 2.5 to 3.5 cubic feet per minute measured at stand ard conditions per pound of carbonaceous de cyclone separators not shown in this Fig. 2 but fully illustrated in Fig. 1. . rThe pressure in the regeneration chamber may posits to be burned from the catalyst per hour. 76 vary between 1 and 30 atmospheres absolute. The 2,412,098 ' 7 amount of cooled regenerated catalyst .added to 1.- In the method of regenerating a spent pow-- the regeneration vessel or chamber, -as compared with the amount of spent catalyst added there for,> may vary within the limits of from 0.75 to 6 parts by Weight of regenerated catalyst to 1 - dered catalyst i'n which said powdered catalyst is suspended in a free-oxygen-containing gas and part ofpspent catalyst. 'I'he amount of oxygen added to conduits IIJ-a, w8', |20 and i3! will ob viously depend on the amount required to consume regenerated catalyst in a free-oxygen-containing passed through a regeneration zone, the improve ments which comprise suspending a hot, recently gas, cooling the last-named catalystsuspenslon, intermixing the suspension of regenerated and a by oxidation the contaminants deposited on the catalyst and the amount of spent catalyst passing 10 suspension of spent catalyst, discharging the mixture into >the regeneration zone, maintaining through the regeneration vessel lZ-a in a given time. -Ordinarily the catalyst will contain from _ said mixture in said regeneration zone in a highly agitated state by causing the mixture to iiow in 1% to 3% carbonaceous deposit by Weight, and the reaction zone inv a multiplicity of 'vari-direc it can be assumed that this is largely carbon, al tional currents and for a suñ‘icient period of time though, of course, there is some hydrogen present to effect the desired regeneration, recovering the in the form of hydrocarbons of high unsaturation. total catalyst discharged from the regeneration The amount of air supplied to the regeneration zone and resuspending a portion of the hot re vessel l2--a should be 2.5 to 3.5 cubic feet per generated catalyst in additional free oxygen-con minute measured at standard conditions per l pound of carbonaceous deposits to be burned from '20 taining gas as aforesaid. 2. In the method of regenerating spent pow-l the catalyst per hour. dered catalyst in which said powdered catalyst ` The temperature of the inlet air may vary from is suspended in a free-oxygen-containing gas and passed through a regeneration zone, the improve atmospheric to 800° F. The temperature of'the recycled catalyst may vary from 400° to 1100° F. The temperature of the contaminated catalyst 25 ments which comprise suspending a hot, recently regenerated catalyst in a free-oxygen-containing gas, cooling the last-named suspension, suspend ing a spent catalyst in a free-oxygen-containing may vary from 650° to 1000° F. (depending on the temperature in the catalytic conversion proc ess which caused the contamination). The mini mum temperature at any point in the regenera gas, intermixing the suspensions of spent and re- ' generated catalysts, discharging the mixture into tion chamber maybe from 750° to 950° F. The a regeneration zone through a number of per forated pipes extending vertically over a substan tial portion of the regeneration zone and direct temperature of the suspension leaving the cham ber may be preferably from 1000° to 1100)’ F., but certainly Within the range from 900° to 1200u F. _ ing flow horizontally into the regeneration zone` ~ so as to thoroughly agitate and intermix the mix It is to be understood that the methods de scribed above for regenerating the catalyst and making it suitable for further use are also appli ture within said regeneration zone, permitting the catalyst suspension to remain resident in the -regeneration zone in a highly agitated state un cable to the reviviiication of spent clays from der regeneration conditions for a sufficientperiod other processes in which certain clays are ren dered less active by deposits of combustible ma 40 of time to effect the desired regeneration, with drawing the regenerated catalyst in suspension terials. V l from the regeneration zone and resuspending a Having described the speciñc embodiments, -it portion of the hot regenerated catalyst in addi tional free oxygen-containing gas as aforesaid. will be understood that the invention embraces such other variations and modiñcations as come within the spirit and scope thereof. What we claim is: 45 JACKSON R. SCHONBERG. DONALD L. CAMPBELL.