Патент USA US2406547код для вставки
Aug. 27, 1946. P_ E, KUHL 5|- AL 2,406,547 CATALYTIC CRACKING PROCESS Filed Sept. 7, 1940 1 m” 25 2e 1 62 CONDEAISER JEPARATING ‘VESSCL 27 2.922 24 J! 21! I OWlR 4 17 6 —. .SIPAZATING VEJJEL DIST’ ’ 415 um OOTLE C L A TION UM” 2,406,547 Patented Aug. 27, 1946 UNITED STATES PATENT OFFICE 2,406,547 CATALYTIC CRACKING PROCESS Paul E. Kuhl, Madison, and Albert B. Welty, Jr., Roselle, N. J., assignors to Standard Oil De velopment Company, a corporation of Delaware Application September 7, 1940, Serial No. 355,740 2 Claims. (Cl. 196—52) 1 This invention relates to an improved process for the catalytic cracking of hydrocarbons and has particular reference to methods for prepar ing two or more improved products from a single feed stock. In the catalytic cracking of hydrocarbons, the process may be carried out in such a, manner that both the materials undergoing cracking and the catalyst are passed continuously through the cracking zone. With this type of operation the composition of the cracked products remains sub 2 of a gas oil fraction of the cracked products which is especially suitable for further catalytic cracking and which may be used as a cycle stock in the process. Another object of the present invention is to provide an improved process for the catalytic cracking of hydrocarbons in which there are pro duced low boiling and gaseous products which are particularly adapted for treatment in other proc 10 esses involving recovery of hydrocarbons from the cracked gases or the use of the cracked gases for gas reversion, polymerization, the production of stantially uniform for any ?xed set of reaction specialty products such as alcohols and the like. conditions. Other and further objects of this invention Another method of catalytic cracking is con ducted. by passing hydrocarbons through a re 15 will be apparent from the following description and the drawing. action zone having a cracking catalyst main The drawing is a diagrammatic illustration in tained therein and periodically stopping the ?ow partial sectional elevation of an apparatus suit— of hydrocarbons and regenerating the catalyst able for carrying out a process involving one by passing suitable oxidizing gases through the reaction zone. The operation thus comprises a 20 modi?cation of the present invention and illus trates the ?ow of materials. series of cycles of alternate cracking of hydrocar Turning to the drawing, a suitable hydrocar hens and regeneration of the catalyst. It has bon stock for catalytic cracking, such as a pc now been found that the nature of the cracked troleum gas oil, is supplied in line I and is passed products changes materially during the cracking by pump 2 through a vaporizing coil 3 to an inlet cycle in such a “run-blow" operation and that it manifold ll. Vapors pass from this manifold is advantageous to segregate these products in through line 5 into a vessel 6 which contains a accordance with their individual ?tness for the packing or ?lling of a suitable cracking catalyst production of different ?nished products such as 1, such as an active or activated clay or a syn aviation gasoline, Diesel oil, etc, and for further 30 thetic gel type catalyst containing oxides of utilization in other processes. silica, alumina, magnesia or various combinations One object of this invention is to provide a of such oxides. The catalyst 1 may be disposed process for the catalytic cracking of hydrocar in the vessel 6 in any suitable manner, such as bons by which cracked products of widely dif by being packed in this vessel or being placed ferent characteristics may be prepared. Another object of this invention is to provide . therein on trays, in baskets and the like. Or the catalyst particles may be partially or even sub a catalytic cracking process which is especially stantially completely suspended in a rising stream adapted for ‘the preparation of improved avia of gas or vaporous reagents, being thus main tion gasoline. tained in the reaction vessel, in a state of limited Another object of this invention is to provide or vibratory motion. It is desirable that substan a catalytic cracking process which is especially tially all of the catalyst remain in the reaction adapted for the preparation of products of high vessel and that any carried out of the reaction aromatic hydrocarbon content. vessel with the gaseous products be separated Another object of this invention is to provide therefrom and returned to the reaction vessel or an improved process for the catalytic cracking of that a relatively stationary mass of catalyst be hydrocarbons by which motor gasoline may be used to treat the ?owing stream of hydrocarbons. produced with a minimum of re?ning treatment. _ The cracked hydrocarbons leave the vessel 6 Another object of this invention is to provide by line 8 and are passed through line 9, condenser an improved process for the catalytic cracking of ill and line I! into a separating vessel l2. Un hydrocarbon oils which is adapted to produce an condensed gaseous products are withdrawn by improved Diesel fuel having a high Diesel index, . line i3, liquid products by line H and any water and which is also especially suitable for the pro present in the cracked products (such as that duction of high quality kerosene. resulting from the use of steam in the vaporiza Still another object of the present invention tion and/or cracking zones) by line IS. is to provide an improved catalytic cracking The cracked products leaving the condenser l0 process which is characterized by the production 55 3 2,406,547 4 may also be passed by line IE to a second sepa high to remove carbonaceous material from the rating vessel I‘! provided with a line l8 for taking catalyst, but should not be permitted to rise at off uncondensed gases, line 19 for oils and line 20 any time high enough to injure the activity of for water. the catalyst. The regeneration temperature is Means are also provided for regenerating the 5 preferably maintained between about 800 and catalyst by treatment with air or other suitable 1100°, and temperatures exceeding 1200° will gen oxidizing gases. These comprise a gas supply erally be found harmful to the activity of the line 2| from which an oxidizing gas is passed by ‘silica-alumina type of cracking catalysts. blower 22 through manifold 23 and line 24 into The operation of the apparatus illustrated in vessel 8. The regenerating gases leave the vessel 10 the drawing will now be described in connection 6 by line 25 and may be vented through line 26 ' or a part thereof may be recycled by line 21 to the blower 22. with an example illustrating a suitable manner for conducting the process of this invention. EXAMPLE 1 One or more alternate catalytic cracking ves sels, such as the vessel 28, may be used in parallel 15 A petroleum gas oil distillate fraction boiling connections with the vessel 6 so that one vessel between about 500 and 700° F. and having a may be used for cracking hydrocarbons while density of 33“ A. P. I. and an aniline point of the catalyst in the other vessel is undergoing re 174° F. is supplied as the feed stock and is heated generation. For example, the vessel 28 is pro rapidly in the vaporizer 3 to a temperatue of about vided with a hydrocarbon vapor supply line 29 910° F‘. as rapidly as poss‘ble in order to avoid and cracked products withdrawal line 30, a re the formation of coke. Any unvaporized mate generating gas supply line 3| and a regenerating rial may be separated from the products leaving gas drawoil‘ line 32. the vaporizer 3 and the vapors are then passed The cracked products collected in vessels l2 through manifold 4 and line 5 into vessel 6 which and I 1' may be subjected to any suitable rectifica 25 conta‘ns a fresh or freshly regenerated cracking tion and re?ning treatments to prepare aviation catalyst at a temperature of aboue 850° F. Hy gasolines, motor gasolines, kerosene, burning oil drocarbon vapors are passed through the crack distillates, Diesel oils, fuel oils and the like as ing vessel 6 at a rate of about 0.3 volume of hy may be desired. For example, the liquid con~ drocarbon (liquid base) per volume of the cata densate received in vessel I‘! may be passed by 30 lytic cracking zone per hour. The cracked line I! through heating coil 33 into a distillation products are withdrawn from vessel 6 through column 34 which may be operated to separate lines 8 and 9 and are passed through condenser cuts or distillate fractions of any desired vola l0 into the separating vessel l2 by line I I. After tility. For example, a column may be operated the cracking vessel has been in use for a time so as to take off the overhead distillate through 35 the activity of the cracking catalyst undergoes line 35, a heavy naphtha fraction through line 36 from the trapout tray 31, a gas oil by line 38 from the trapout tray 39 and a residue by line 40. a change which is evidenced by changing char acteristics in the cracked products. The sepa rating vessel 12 is then shut off and the cracked The gas oil may be used as cycle oil in the process products are passed from the condenser I0 and may be recycled by pump M and line 42. It 40 through line I6 into vessel I1. After further use may also be withdrawn by line 43 for treatment the activity of the cracking catalyst decreases to by any other suitable process, such as cracking, the extent that further operation is undesirable catalytic cracking or destructive hydrogenation. and the supply of hydrocarbon vapors is shut oil’ The condensate collected in vessel l2 may also in line 5 and is diverted through the manifold 4 be fractionated in the tower 34 or in a separate and line 29 to vessel 28 which at this time con tower. it being preferred to keep the condensates 45 tains a fresh or freshly activated cracking cata in vessels I2 and I1 separate in the distillation lyst and which may be operated under the same and refining treatment until substantially ready conditions just described for cracking vessel 5. for blending into ?nished products. The cracked hydrocarbon products leave the The catalytic cracking operations of this in vessel 28 by line 30 and, during the initial stages vention are preferably conducted at elevated tem 50 of the cracking cycle, are passed through line 9, peratures, such as for example, from 600 to 1200° condenser I0 and line H into vessel I2. During F., preferably between about 650 and 1000“ F., the latter stages of the cracking cycle these and with the hydrocarbons substantially com cracked products are diverted through line I6 pletely in the vapor phase. The time of treat ment should be adjusted in regard to the crack 55 into vessel l1, the vessels i2 and I‘! thus serving to receive cracked products from the initial and ing temperature, catalyst activity and other fac ?nal portions, respectively, of the cracking cycle tors, so as to secure a conversion of about 25 to from each of the cracking vessels. 65% of hydrocarbons boiling below 400° F. from While the vessel 28 is being used on the crack the heavier hydrocarbons passed through the 60 ing cycle, the catalyst in vessel 6 may be under cracking zone. The feed rate will ordinarily be going regeneration. This is accomplished by between the limits of about 0.1 and 20 volumes of forcing an oxidizing gas such as air, which is oil (liquid basis) per volume of cracking zone per preferably diluted with steam, nitrogen, ?ue gas hour and the operation is preferably conducted or the like, in order to avoid too rapid oxidation with a feed rate below about 5.0. The length of the cracking cycle will also depend largely on 65 of the catalyst, by means of a blower 22 through the manifold 23 and line 24 into the vessel 6. the activity of the catalyst and may range from The regenerating gas is preferably supplied in 10 minutes to about 12 hours, and cycles of longer manifold 23 at a temperature of about 700-800u than about 20 minutes each are generally pre F. and at such a rate and oxygen content that ferred. 70 the temperature of the catalyst 1 does not rise Following the cracking cycle, the catalyst is above about 1100“ F. at any time during the re regenerated by treatment with suitable oxygen containing gases, such as air, air diluted with ni trogen or steam, ?ue gas and the like. The tem generation. When the catalyst is substantially regenerated, as indicated by a dropping off in the oxides of carbon in the used regenerating gases perature of regeneration should be sufficiently 75 leaving vessel 6 by line 25 and by decreasing 2,406,547 catalyst temperatures, the vessel 6 is ready for use again in cracking hydrocarbons. The re generating gas may then be cut oil‘, the catalyst purged with steam or inert gas to remove oxy C4 hydrocarbons were produced during an 811 tire four hour cracking cycle, while in the ?rst thirty minutes of this cycle 4.5% by weight of dry gas and 7.5% by weight of C4 hydrocarbons were produced. 01’ the C1 hydrocarbons pro duced during the ?rst thirty minutes, 32% were gen, and hydrocarbon vapors may be again sup plied by line 5, thus starting a fresh cracking cycle for this vessel. The cracked products ob tained in the initial stages of this cycle are passed unsaturated, while 41% of the 64 hydrocarbons produced during the entire four hour cycle were unsaturated. Thus it is desirable to segregate to vessel l2 and those from the latter stages of the cycle to vessel H as before. The catalyst 10 the gas produced during the di?erent stages of the cracking cycle in accordance with its in in vessel 28 may similarly be regenerated during tended use. The gas from the initial stages of the carrying out of the cracking cycle in vessel 6. the cracking cycle is advantageously segregated It will be understood that the process may be for use in gas reversion-catalytic cracking proc conducted with any additional number of reac esses or where the recovery of the entire 04 cut 15 tion vessels as may be desired and that these is desired, while the gases from the latter por can be used in parallel with vessels 6 and/or 28 tion of the cycle may be used for the production or in any intermediate stages between these of a C4 out which is intended for polymerization vessels in the cracking and regenerating cycles. or for the production of specialty products such Provision should be made for segregating the products obtained in the initial and ?nal stages 20 as alcohols. EXAMPLE 2 of the cracking cycle from all such vessels, which may be done by connecting their cracked prod There is presented in the following table an ucts outlet lines to vessels l2 and I1. outline of the operating conditions used and of It will also be understood that provision may be made for segregating the products obtained 25 the results obtained in catalytic cracking of an East Texas petroleum gas oil distillate fraction of in any desired number of portions of the crack 33.3° A. P. I. over an activated clay cracking cata ing cycle, for example, other receiving vessels lyst at a feed rate of 0.3 vol. of oil per volume of may be connected to receive cracked products catalyst per hour. The products from six consec in parallel with vessels 1! and I1, and the prod ucts of any intermediate portion of the cracking 30 utive periods of six cracking cycles were separately collected and composited for each period, each cycle may be separately collected in any of such composite product then being distilled for maxi vessels. mum workings of aviation gasoline, heavy naph In carrying out the process of this invention tha and l2# Reid vapor pressure, 400° F. end point as described in the above example, it has been noted that the products obtained in the initial 85 gasoline. Segregation of Products from Portions of the Cracking Cycle Parti'oi cracking cycle 1 Length, hrs ___________________________________________________________ __ 2 3 4 5 0-0. 25 0. 26-0. 50 0. 50-1. 00 1. 00-2. 00 1. 00.3. 00 904 907 6 B. 004. 00 Operating conditions: Temperatures, ° F.— Reactor inlet _________________________________________________ _. _ Reactor outlet _________________________________________________ __ Yields on oil led: l2# R. V. P.—400° F. E. P. gasoline, per cent vol ________ __ 910 911 B61 883 873 851 877 874 842 853 860 849 836 832 872 844 867 846 852 847 839 822 50. 5 46. 6 41.1 29. 1 Aviation gasoline, per cent vol 29. 8 25. 9 23.0 16.4 Heavy naphtha, per cent vol ____________________________ ._ l4. 2 14. 7 13. 0 9. 5 24 29 37 60 111 117 115 104 Aviation gasoline inspections: d best, ° _____________________________________________________ .- Aniline point, ° F ___________________________________________ __ __ Heavy naphtha inspections: Acid heat, “ ____ _. Aniline point, ° F._ l2# R. V. P.—-400° F. E ll l0 12 19 30 54 59 73 28 33 40 57 ll 10 10 inc inspections Acid heat, °F ____________________________________________________ .- Bottoms or cycle stock inspections: Acid heat, ° F ___________ -- Aniline point, ° F Gravity, " A P _____ __ 7 126 135 145 158 25. l 28. 2 30.4 32. 4 ‘Z7. 2 7. 2 34. 6 8- 9 41. 2 10.9 48. 3 16. 8 04 cut inspections: Total unsaturates, per cent ________________________________________ _. Isobutylene, per cent ______________________________________________ __ It will be seen from the above table that the stages of the cracking cycle are quite different distillate fractions of the cracked products boil from those obtained in the latter stages and that very great advantages may be secured by ” ing in the motor fuel range are characterized by an increase in the unsaturate content and a de segregating these products. For example, more crease in the aromatic content as the cycle pro hydrocarbons of 4 carbon atoms per molecule gresses. It is desirable to segregate the distillate are formed at the beginning of the cycle than from the ?rst part of each cracking cycle for the at the end, while those produced at the end of the cycle contain the greater proportion of un 70 production of aviation gasoline. Finished avia saturates. For example, operating under con ditions similar to those described in the above example, 3.5% by weight (based on the feed to the cracking zone) of dry gas (free of C4 and tion gasoline should have a low acid heat repre senting a low content of ole?nic hydrocarbons. The aviation gasoline produced in catalytic crack ing operations usually has an excess of such un» heavier hydrocarbons) and 2.7% by weight of 75 saturates, and in ?nishing the gasoline to aviation 7 2,406,547 speci?cations, these unsaturates must be removed. Re?ning losses are decreased and the re?ning process simpli?ed by selecting the distillate frac tions of the ?rst portions of each cracking cycle tained in the latter stages of the cracking cycle are particularly suited for the production of kerosene. Aromatic and unsaturated hydrocar ?fteen minutes of the cracking cycle was 24° F fractions of the cracked product of the latter stages of the cracking cycle and to subject this to suitable re?ning treatments for the production of water white kerosene. The heavy fractions of the cracked products bons are both undesirable in kerosene used for for the production of aviation gasoline. In an to lighting purposes. The unsaturates may be read illustrative process conducted as described in the ily removed by treating, but the removal of arc above example, the acid heat of the aviation gas matic compounds is much more dif?cult. Thus oline distillate fraction produced during the ?rst it is preferred to segregate the kerosene distillate while the acid heat of the aviation gasoline pro- " duced during the third hour of the cracking cycle was 60° F. The aromatic content of the distillate fraction of the cracked products is also greatest at the beginning of the cracking cycle and the segrega v15 not used to produce Diesel oils, fuel oils or kero sene as described above may be subjected to fur tion of this ?rst distillate for the production of ther cracking or other destructive treatments to aromatic solvents and of even more highly con produce motor fuels. The entire heavy fractions centrated aromatic hydrocarbons is also advan may be used as cycle stock in the process of this tageous. For example, the heavy naphtha dis invention. However, it is preferable to segregate the heavy fractions produced during the latter tillate fraction boiling ‘between about 300 and 400° F. of the products obtained during the ?rst ?fteen minutes of the cracking cycle under op erations similar to those described in the‘ above example had an aniline point of 30° F. and an portion of the cracking cycle and to use it as cycle stock in this process, as this portion of the heavy fractions has a higher aniline point and higher gravity than that produced during the ?rst part of the cracking cycle and is better acid head of 11° F., while the heavy naphtha dis- , tillate fraction produced during the third hour of the cracking cycle had an aniline point of 73° tha fraction of the products of the early portion of the cracking cycle with liquid sulfur dioxide, phenol or other selective solvents, to concentrate the aromatic hydrocarbons therein. The segregation of the motor fuel distillate adapted to cracking for maximum yield of gaso line. The heavy fractions obtained in the early stages of the cracking cycle are relatively more aromatic in character and are less suitable for catalytic or non-catalytic cracking. These frac tions, however, may be subjected to destructive hydrogenation under conditions suitable for the production of gasolinesv high in aromatic con tent, and form a desirable feed stock for such fractions produced during the various stages of the cracking cycle is also advantageous in that the degradation of the gasoline and the treat— This invention is not to be limited by any speci?c examples or explanations presented F. and an acid heat of 19° F. Aromatic solvents of high purity are thus prepared by any suit able treatment, such as by extraction of the naph- , 30 treatment. herein, as all such are intended solely for pur pose of illustration. It is the applicants’ inten ' _tion to claim their invention as broadly as the ing costs are decreased. In the ?nishing of the motor fuel distillates to motor gasoline speci?ca tions, the motor fuel distillate fractions pro duced in the early stages of the cracking cycle prior art permits. We claim: are quite stable and in many cases will be' found to be suitable for use directly as gasoline or after a. very slight re?ning treatment to remove any - - ~ 7 l. A hydrocarbon oil conversion process which comprises providing a bed of fresh cracking cat alyst and maintaining said bed at catalytic con version temperature during a period of process mercaptans present. The motor fuel distillate fraction produced during the mid portion of the cracking cycle is somewhat less stable and usually requires a mild re?ning treatment, while the ing, continuously passing a stream of hydrocar bons through the catalyst bed during the process motor fuel distillate fractions produced in the last part of the cracking cycle are relatively un ing period and converting a substantial portion of the hydrocarbons into gasoline in said bed, stable and require more severe re?ning treatment. said stream being introduced to said bed at a Also, the gasoline produced in the early part of the cycle usually is sweet, but, especially with substantially uniform conversion temperature throughout the processing period, whereby the activity of the catalyst is gradually diminished by deposition of carbonaceous matter thereon, high sulfur feed stocks, there is a tendency for the gasoline produced during the latter stages of 55 the cycle to become slightly sour. In this case, producing from the hydrocarbons a substantial the ?rst gasoline produced may by-pass the ly saturated gasoline during the initial portion sweetening treatment and thus save considerable of the processing period when the catalyst bed handling expense. is in a state of high activity and an unsaturated The heavier fractions of the cracked products 60 gasoline during a subsequent portion of said boiling above the motor fuel range are charac period when the catalyst bed is in a state of diminished activity, and separately collecting said substantially saturated gasoline and said unsat terized by a decrease in the content of aromatic hydrocarbons and an increase in the unsaturate; content as the cracking cycle proceeds. The*' ‘ gravity and aniline point of these heavy frac— tions produced during the last part of the crack ing cycle are higher than those of the heavy fractions produced during the ?rst part of the _ urated gasoline. 2. A hydrocarbon oil conversion process which comprises providing a bed of fresh cracking cat alyst and maintaining said bed at catalytic con ‘version temperature during a period of process‘ cycle; the Diesel index is therefore greatest for.‘ _ ing, continuously passing a stream of hydrocar the heavy fractions of the cracked product pro bons through the catalyst bed during the process duced in the latter stages of the cracking cycle. ing period and converting a substantial portion The segregation of these heavy fractions for the ‘of the hydrocarbons into gasoline in said bed, production of Diesel fuels is thus advantageous. ‘said stream being introduced to said bed at a Similarly, the fractions boiling in the kerosenei substantially uniform conversion temperature or burning oil range of the cracked products 010- ‘3 throughout the processing period, whereby the at 2,406,547 activity of the catalyst is gradually diminished by deposition of carbonaceous matter thereon, producing from the hydrocarbons a substantially saturated gasoline during the initial portion of the processing period before there has been de posited on the catalyst bed a su?icient quantity of carbonaceous matter to materially impair the catalytic activity of the bed, condensing and col lecting the saturated gasoline thus formed, pro 10 ducing from the hydrocarbons an unsaturated gasoline during a subsequent portion of the proc essing period when the catalyst bed has received a sufficient deposit of carbonaceous matter to substantially reduce its catalytic activity, and condensing and collecting said unsaturated gas oline independently of said saturated gasoline. PAUL E. KUHL. ALBERT B. WELTY, JR.