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Nov. 12, 1946. R. N. MEINERT E'rAL 2,410,891 PROCESS FOR IMPROVING NAPHTHA Filed Dec. 8, '1944 ._u«ndordáuzn Richard bq'lt mez'nerf '3ra venters Y / ,f ze Jr _ l Clbbotneq 2,410,891 Patented Nov. 12,1946 ` UNITED STATES IkPATENT -oFElcE rRocEss Fon IMPRovrNG NAPHTHA Richard N. Meinen, Westfield, and Pnuetus n. Holt, 2nd, Summit, N. J., assìg'nors to Standard 0il Development Company, a corporation of Delaware Application December 8, 1944, Serial No. 567,278 2 Our present invention relates to improvements in the catalytic-reforming of naphthas in a “iluìd" catalyst process in which a heat .balance is main tained in the system by controlling coke forma ’ tion and the ratio of hydrogen which is recycled with respect to the naphtha fed to the system, all of which will more fully appear hereinafter. In catalytic cracking in a system involving a reaction zone and a regeneration zone, it has been proposed to supply the amount of heat necessarir 10 and molybdenum oxide or chromium oxide. The molybdenum oxide or the chromium oxide which comprises 8 to 12 per cent of the total composi tion is the active component whereas the zinc spinel is the carrier or spacing agent. We have found that this catalyst, particularly when em ployed in the process maintained under relatively low pressures, not only converts naphthenes to the corresponding aromatic by dehydrogenation but also converts parafiins to aromatics. Hence, it is possible by our process to convert a virgin for the endothennic reaction of cracking by burn naphtha having an octane number of, say, 40 ing the cokev formed during cracking in a re CFR to a product having an octane number of generation zone. It is not possible to maintain from 85 to 100 on the same scale, in good yields. such a system in heat balance without the use of coolers and/or heaters, because there is no varia 15 In the accompanying drawing we have shown diagrammatically apparatus elements in which a ble at a given conversion of oil to gasoline, since preferred modification of our invention may be the amount of coke formed is fixed by conditions. carried into practical eiîect. Similar reference In catalytic reforming we have found that the characters refer to similar parts. reforming (endothermic) reaction may be main tained in heat balance with the regeneration 20 Referring in detail to the drawing, a West Texas virgin naphtha, in the example we have phase (exothermic) by adjusting a variable, namely, the quantity of hydrogen used in the chosen to illustrate our invention, is introduced into the system through line I. This naphtha is process, thereby increasing or decreasing the at a temperature of around 400° F., having been amount of coke formed. To illustrate, suppose pre-heated by heat exchange with hot products that for a given degree of reforming it developed in a subsequent portion of the system according that more coke was formed on the> catalyst than that required when burned in the regeneration to known means (not shown). The feed is mixed with a hydrogen-containing gas as its enters the phase to sustain the reaction phase, then the coke formation may be reduced by increasing the system, the .purpose of the hydrogen being to di catalytic reforming of naphthas in the process in which there is a productive phase and a catalyst in suspension by the vaporized naphtha in the quantity of hydrogen feed to the reaction zone 30 rect the course of the reaction as previously indi~ cated, particularly with regard to the formation f which has the eñ'ect of reducing the amount of coke formed in the reaction phase and burned in of coke which is unavoidably formed in an op eration of the type here involved. 3 is a catalyst the regeneration phase. On the other hand, ifit regenerator andl from 3 we withdraw through a so happens that the amount of coke produced on the catalyst in the productive phase is less than 35 standpipe 4 controlled by a valve V a quantity of powdered catalyst which is discharged into line- that required when burned in the regeneration I, where it admixes with the naphtha feed and phase to sustain the endothermic reaction of the y productive phase, then the quantity of coke being the hydrogen, and due to the fact that it is at a temperature of about 1100“ F. it causes vaporiza formed may be increased by reducing the quan 40 tion and super-heating of the naphtha. to a tem tity of hydrogen feed to the reaction zone. perature of about 950° F. The catalyst is carried 'I_'he object of our invention is to operate with hydrogen into a delayed settler reactor 5. Within the reactor the gas or vapor velocity is main' regeneration phase under operating conditions such that the system is rendered internally heat 45 tained within the limits of from about 1/2 to i0 ft..per second, preferably from 1 to 2 ft. per sec compensating without resort to the use of coolers ond, depending upon the particle size of the pow and/or heating means. dered catalyst. Ordinarily, the catalyst has a >A more specific object of our invention has ref particle size of from about 100 to 400 mesh, with erence to controlling the amount of coke which is formed on the catalyst during the catalytic re-> 50 a particle size of about 200 mesh .being preferred. forming of naphthas in the presence of _added hy The result of the flow conditions and the particle drogen. size within the reactor 5 is to form a dense sus „ ’ We have found that the catalyst best suited for reforming naphthas is one consisting of a zinc pension of catalyst in reactants which will have an upper dense phase leve1 at L, depending on _ alumina composition commonly called zinc spinel 55 the weight ratio of -catalyst to oil in the reactor, 2,410,891 3 or the amount maintained therein, because as will subsequently appear, catalyst is being continu ously withdrawn from the reactor to be regen the case of the reactor, a catalyst disengaging erated. We shall set forth, hereinafter, tables ' containing operating conditions within the re off pipe 4 as previously indicated and the cycle is repeated. We have thus described generally a method of actor. space. The regenerator catalyst issues through draw The reactants pass through the dense phase carrying our improvements into en’ect. We do of catalyst into the space S above L where the not claim novelty in the iluidized type of opera amount of catalyst suspended in the vapors de tion we have described but as previously indi creases sharply upward due to the settling out of 10 l'cated in the manner of maintaining the system in the catalyst and then the vapors pass through heat balance without the aid of extraneous equip one or more centrifugal separators C disposed ment and utilities. To illustrate this proposition, in the top of the reactor where entrained cat we direct attention to the fact that where, say, alyst ñnes are substantially separated from the the temperature of the catalyst in the regener feed vapors and returned by-a dip pipe D (or 15 ator is 1100° F. and that in the reactor 900° F. it is desired to convert virgin naphtha to gasoline dip pipes) to the main bulk of the catalyst. 'I'he reaction products and hydrogen eventually exit having an octane number of 85, we ñnd that from the reactor through line i0 and then pass < about 2000-3000 lbs. of catalyst must be cir to a puriñcation and hydrogen recovery system culated to the reaction zone per 100 lbs. of oil fed (not shown) for recovery of desired products and 20 Where the incoming feed is at a temperature of return of hydrogen to the reaction zone. It is 400° F. (that is, feed in line l about to be mixed deemed unnecessary to describe the purification with hot catalyst). This means We must Ben `recovery of the desired products since that is well' erate in the regenerator l 36500 B. t. u.'s. It will understood by those who are familiar with the be understood that this is a specific example il-art. 25 lustrating our invention and is not to be taken As previously pointed out, .during the reform as limiting thereon for, obviously, different condi ing of the naphthas, coke is unavoidably de tions will require a different amount of coke to posited on the catalyst and therefore it is neces- v be deposited on the catalyst for burning to supply sary to remove this coke to maintain the catalyst the heat for the system. However, we set forth inthe below tables a full statement of conditions in an active condition. To this end, therefore, we withdraw catalyst continuously through the in the reactor which we have found to give the standpipe I2 carrying taps t and controlled by desired results. valve V. As is well known the taps t are dis Table I posed in the standpipe I2 for the purpose of in jecting a small amount of gas which may be hy Conditions giving good results: drogen, steam- or other inert gas, into the down Temperature ______________ __°F___`- 850-1l00 fiowing catalyst for the purpose of maintaining Pressure _________ __lbs. per square inch-- 0-400 the same in a fluidizedv condition. The catalyst Lbs. of catalyst per 100 lbs. of oil per discharges into an air stream I4 in which it forms hour fed to the reactor__________ __ 500-4000 a suspension which is conveyed to regenerator 3. 40 Table II The catalyst forms in the regenerator 3 a dense suspension having` an upper level at L’ in the The preferred conditions are: regenerator by maintaining the gas flow rate therein of the same order as those previously mentioned in connection with the description of the operation in reactor 5. The catalyst enter ing the regenerator 3 is at a temperature at around 900° F. but during the regeneration Temperature ______________ __° F____ 920-980 Pressure _________ __lbs. per square inch..- 15-50 Lbs. of catalyst per 100 lbs. of oil per hour fed to the reactor__________ __ 2000--3000` In addition to the conditions set forth above, the real gist of the present invention as previous wherein the coke on the catalyst is burned, the ly indicated has to do with controlling the quan temperature is increased to about 1100° F. As in 50 tity of coke which is formed on the catalyst dur the case of the reactor above L’ there is a ing the reaction. If the temperature in the re sparse phase S1 wherein the concentration of actor 5 tends to be decreased below the desired catalyst in gas sharply decreases upward due to value, immediately the quantity of hydrogen feed settling out of catalyst so that eventually it con to the reactor is reduced, thereby permitting the tains only theflner portions of the catalyst. The formation of additional coke on the catalyst, gas containing the fines is then passed through which additional coke when burned in regen one or more cyclone separators C1 wherein the erator 3 will, of course, supply an additional catalyst fines are substantially removed, permit quantity of heat which would be absorbed by the ting the issuance of the regeneration fumes from catalyst and returned to the reactor to correct regenerator 3' through line 20 substantially freed 60 the unfavorable temperature condition therein of catalyst. Of course, it will be understood that tending to take place. Of course, the actual the sensible heat contained in the regeneration amount of hydrogen which is fed to the reactor fumes is preferably, in at least part, recovered per barrel of oil in order to maintain the desired by causing the passage of the hot f es through conditions herein enumerated will depend on the heat exchangers, waste heat-boilers, and the like. 65 feed stock. Generally speaking, the amount of ‘This is accomplished in equipment not shown. hydrogen is within the range of from about 1000 Thus, for example, as previously indicated, the to 4000 cubic feet measured under standard con cold oil entering the system may bepre-heated ditions per barrel of oil. But as previously by heat interchanging with these fumes or with pointed out, it may be and often is necessary to the hot vapors in line I0 according to known 70 change the ratio of hydrogen to oil to accommo means. vThe regenerator is provided with a dip date a particular feed stock, or the same feed pipe D1 which serves to return catalyst separated stock as a catalyst gradually decreases in ac from the gas in separator C1 and returned to the tivity during long-continued use. It is, of course, main body of catalyst below L1. The space S1 be impossible to set forth numerical values defining tween L1 and the top of the regenerator is, as in 75 every possible set of conditions but _we may indi 2,410,891 cate the amount of hydrogen necessary by refer ence to the following guide: ’ Let us assume that the plant is operating in the reforming of a West Texas virgin naphtha under conditions generally speciñed in the above tables and that for every 100 lbs. of oil fed to the system there is formed 4 lbs. of coke, that is to say, the system is producing high octane gasoline, 6. oxide and chromium oxide, maintaining a tem perature of from 850 to 1100° F. and a pressure of from about 15-50 pounds per square inch within said reaction zone, permitting the react ants to remain resident in the reaction for a sufficient period of time to effect the desired conver sion, continuously withdrawing a reformed naph tha. from an upper portion-of said reaction zone, same gasoline having an octane rating of 85; that the temperature inthe reaction zone is 950° l0 continuously withdrawing the catalyst fouled during the reaction from said reaction zone at _F. and that in the regenerator 1100“ F.; that a lower point thereof, mixing said withdrawn cat there is fed to the reactor 30 lbs. of catalyst per alyst with an oxygen-containing gas and con pound of oil; and ñnally, that there is fed to the ducting it to a regeneration zone where it is reactor.2000 cubic feet of hydrogen per barrel formed into a lower dense phase suspension and of oil. It then develops that the temperature in an upper dilute phase suspension of said pow the reactor tends to decrease. In that situation, dered catalyst in said oxygen-containing gas, the amount of hydrogen fed to the reactor is im permitting the catalyst to remain resident in the mediately lowered, say, to 1500 cubic feet of hy regeneration zone for a suflicient period of time drogen per barrel of oil, which lowered hydrogen to eiîect the desired regeneration, continuously feed will 'be reñected in a greater amount of coke withdrawing catalyst from a lower portion of said formation so that the coke rate rises, say, to 5 regeneration zone, returning said regenerated per cent by weight on feed. When this catalyst catalyst directly to the reaction zone and main is withdrawn from the reactor and regenerated, taining the reaction zone at reaction tempera it will of course liberate a greater quantity of tures without employing extraneous utilities by heat than the preceding portions and when this additional increment ofvheat contained in the 25 increasing the amount of hydrogen fed to the re action zone as the temperature therein tends to catalyst is delivered back to the reaction zone it rise and, conversely, decreasing the amount of will counteract the tendency of the temperature hydrogen fed to the reaction zone as the tem-1l therein to decrease. As previously indicated, it perature therein tends to recede, thus forming is diilicult to give numerical values for all possible types of feed, for they may include virgin naph 30 that amount of carbonaceous material on the catalyst during the reaction so that when the thas, cracked naphthas, or mixtures of the two. catalyst is regenerated in the regeneration zone, However, our experience has been that the coke formed on the catalyst should amount to from the heat released and absorbed by the catalyst 3 to 7 weight per cent of the oil feed with the 35 is adapted to maintain the reaction. zone at the coke formation amounting to 4 per cent based on desired temperature when the regenerated cat feed giving good results. ' ‘ , . alyst is returned to the reaction zone. Numerous modifications of our invention may 2. 'I‘he method set forth in claim 1 in which be made by those familiar with this art Without 2000 to 3000 pounds of heated catalyst per one departing from the spirit thereof. » 40 hundred pounds of oil are fed to the reaction What we claim is: zone each hour, where the temperature of the in 1. A continuous method for reforming naph coming oil is about 400° F. a'nd further, in which thas which comprises charging a mixture of a the amount of carbonaceous material formed on hydrogen-containing gas and a petroleum naph the catalyst in the reaction zone is between about tha to a reaction zone containing a lower dense 45 4 to 5 pounds per one hundred pounds of oil fed phase suspension and an upper dilute phase sus to the reaction zone. pension of powdered catalyst in gasii‘orm re 3. The method set forth in claim 1 in which actants comprising the naphtha undergoing re- . the catalyst consists of a major portion of zinc4 forming, the said catalyst consisting essentially spinel and a minor portion of chromium oxide. of a zinc spinel carrier supporting one of the class 50 RICHARD N. MÍEUI‘IERT. of group VI oxides consisting oi’ molybdenuml PHILEI'US H. HOLT, 2nd.