US3042196A - Catalytic conversion of hydrocarbon oils with the use of different types of feed oils - Google Patents

Description

E. M. PAYTON ETAL 3,042,196 CATALYTIC CONVERSION oF HYDRocARBoN ons WITH-THE July 3, 1962 USE OF DIFFERENT TYPES OF FEED OILS Filed NOV. 18, 1959 ATTORNEYS SJMZQS Patented July 3, 1962 3,042,196 CATALYTIC CONVERSION OF HYDROCARBON OILS WITH THE USE F DIFFERENT TYPES OF FEED OILS Edwin M. Payton and James W. Slover, Phillips, Tex.,

assignors to Phillips Petroleum Company, a corporation of Delaware Filed Nov. 18, 1959, Ser. No. 853,816 3 Claims. (Cl. 20S- 113) This invention relates to catalytic conversion of hydrocarbon oils. In one of its aspects, the invention relates to a catalytic conversion of Ka plurality of hydrocarbon oils by adding Vthese serially `at spaced points along the axis of a riser lto a catalytic reaction zone, the rst oil added to and, therefore, admixed with the fresh or just regenerated catalyst being the rnost refractory oil and the last-added oil being the least refractory oil. In another of its aspects, the invention relates to a catalytic conversion operation wherein added to the riser of a uid catalytic conversion reactor are the following oils in the order named: a rainate from a solvent extraction zone in which ia cycle oil obtained from a catalytic cracking zone is solvent extracted, a heavy virgin gas oil obtained from a vacuum flashing operation, and a topped crude from a crude oil fractionation system. At least a portion, if, indeed, not all of the vacuum gas -oil can be replaced with virgin gas oil from the crude oil fractionation system.

In a prior art operation employing a uid catalytic cracking reactor, ratiinate obtained from heavy cycle oil solvent extraction was charged to the catalytic operation together with the virgin gas oil. It was `found that the raffinate recycle (unconverted raiiinate) built up in the system, causing backing out of some of the fresh gas oil charge, cutting down on production capacity of the unit.

We have conceived that the catalytic conversion, in the overall, of a crude oil from which gases, gasolines, and distillates boiling below lgas oil have been removed, can be accomplished with increased eiiiciency by adding the raiiinate from the cycle oil solvent extraction zone of such a system to the riser of the fluid catalytic conversion reactor, and therein causing cracking to a real extent of the raflinate and conditioning of the catalyst, following which virgin gas oil, which can include Vacuum gas oil, is added to the mixture of catalyst and raihnate and conversion products of the cracking of the rainate, thus producing la whole adrnixture of cracked products of both the raftinate and the gas oil, containing a catalyst, of such a nature that the mixture can be used for cracking of the topped crude resulting upon the removal of the gases, gasoline, distillates boiling lower than gas oil, and the Vgas oil from crude oil. Thus, in a unitary operation, we can use a single catalyst and a single cracking reaction zone, without loss of throughput, to convert the ordinarily crackable elements of a crude oil.

It is an object of this invention to provide a process for the catalytic conversion of hydrocarbon oils. It is a further object of `this invention to provide -a unitary combination of steps permitting the cracking of all of the components of a crude oil boiling higher than the gasolines and like distillates in a single reaction zone employing a single catalyst. =A further object still of the invention is that of providing an operation in which rainate recycle frorn a heavy cycle oil solvent extraction operation, in a catalytic conversion of cycle oils will not build up. A still further object of the invention is to provide `a series 0f steps in combination in a catalytic ycracking operation in which there is employed la single catalyst and a single reaction zone permitting the conditioning of fresh or just regenerated catalyst so that it can be used to crack various available streams, each `of them at optimum conditions.

' According to the present invention, there is provided a process for the conversion of a recycle raffinate obtained from solvent extraction of -a cycle oil, in turn obtained in a uid catalytic cracking conversion zone, -a gas oil, and a topped crude, which comprises in the order recited, adding said stream serially along the axis of a riser to a fluid catalytic conversion zone at points spaced -so that the catalyst `and resulting conversion products obtained addition of the raflinate to the riser will be a proper medium in which to advantageously and most effectively to introduce gas oil, following which the then resulting mixture of crackedproducts and catalyst will be a proper medium into which topped crude from the distillation of crude oil can be received and cracked, with minimum carbon deposition and maximum gasoline yield.

Referring now `to the drawing, 1 and 2 designate a conventional catalyst regenerator `and reactor for conversion of hydrocarbons in the presence of the catalyst, respectively. 3 is a fractionation zone in which cracked products are fractionated into the usual light hydrocarbons 4, gasolines 5, light and heavycycle oils 6 and 7, respectively, obtaining as a bottoms `from the fractionation zone, a slurry of oil and catalyst unavoidably entrained from reactor 2. This slurry is removed by pipe 8 to settler 9 for treatment, `as later described. 10 is a crude oil fractionation zone in which crude oil charge is fractionated into the usual light hydrocarbon gases, gasolines and naphtha or kerosene distillates 11, 12 and .13, respectively, and into a virgin gas oil 14 yielding topped crude bottoms 15 which can be used -as later described and/or, at least in part, sent to a vacuum flashing .to produce asphalt and a vacuum gas oil. The light and heavy cycle oils 6 and 7 are each of them, at least in part, passed by Way of pipes 17 and 18, together with oil from settler 9 by way of pipe 19 to solvent extraction zone 20 by way of pipe 21. In the solvent extraction zone, there is produced a paraiiinic raiiinate taken off by way of pipe 22. At the foot of the drawing in pipes 23, 24 `and 25, there are fed, by Way of riser 26, rising to reactor 2, raffinate from pipe 22, essentially a parainic gas oil, virgin gas oil by way of pipe 24, and topped crude by way of pipe 25. lIn operation, earlier-used catalyst which has ybeen regenerated in regenerator 1 and/or fresh catalyst is passed by way of pipe 27, into riser 26. Steam is supplied by way of pipe 28 Ito riser 26 and this steam is mixed with a parainic ratiinate and then contacted as a steam-paraflinic raffinate admixture with the catalyst entering riser 26. Here, all of the paranic raflinate and steam which have been admixed contact all of the catalyst forming a paraiiinic rafinate-steam-catalyst admixture in which cracking immediately ensues and is allowed to occur lfor ya period of time suiiicient to condition the entire mass respect to catalyst activity, temperature, and catalyst dilution with oil and catalyst and oil dilution with steam to create the conditions required to receive and to properly undertake the cracking of the Virgin gas -oil supplied by pipe 24 to riser 26. Here, again, all of the virgin gas oil contacts all of .the preconditioned admixture of steam, partly converted paranic raffinate, and diluted and partly used catalyst. In similar fashion, the final admixture and preconditioned catalyst which are now suitable for undertaking `optimum cracking of topped crude are admixed at the juncture of pipes 25 and 26 with topped crude entering riser 26 from pipe 25. It will be understood by those skilled in the art in possession of this disclosure and having studied the same that the diameter of riser 26 is effective to contain and to flow, along principles of fluid flow, large quantities of finely divided conversion catalyst and that this pipe can have, at any point, a `diameter designed to contain a sufficient amount of preconditioned mixture for a suiiicient amount of time, usually of the order of tenths of one second, to enable, prior to the entry of each succeeding oil stream, the conditioning of the catalyst, steam, already partly cracked oil and its diluted condition to provide optimum cracking conditions for the newly introduced oil. Also, as will be understood by those skilled in the art, cracking continues in riser 26 and is completed in reactor 2, from which products are taken overhead by way of pipe 29 Ito fractionation zone 3 for fractionation as earlier described.

Provision is made according to the invention to pass bottoms from settler 9, 30, 31 and 32 into pipes 23, 24 and 25, respectively, and this provides a trim adjustment of the overall catalytic activity of the catalyst oil and steam fadmixture in pipe 26. This feature of the invention importantly assists in the building of catalyst activity to control the reaction at points along riser 26, at which pipes 23,' 24 and 25 communicate therewith.

Theoil recovered from settler 9 is, in essence, a heavy gas il or cycle oil and this oil is passed to the solvent extraction zone with the` other cycle oils of the system. From this solvent extraction Zone, in which a solvent such as sulfurdioxide is usually employed, there is removed by Way of pipe 33, an aromatic gas oil .preeminently suited for the production of carbon black by the so-called fwrnace method. Further, according to the invention, vacuum gas oil, which is a heavy virgin gas oil and which contains the metal contaminants of the crude oil to a large extent, is returned to the system from the vacuum distillation by way of pipe 34 and passed by way of pipe 24 to riser 26. It will be noted that the catalyst, upon reaching the juncture of pipes 24 and 26, has been preconditioned by cracking therewith the paraftnic raffinate and that, therefore, metal contaminants do not deposit on the catalyst but rather onto a layer of coke which has already formed on the catalyst particles. Likewise, the topped crude is added t0 the catalyst mass after it has been conditioned and, therefore, metal contaminants will be burned from the regenerator and be removed by way of the flue gas pipe 36 during regeneration in regenerator 1 of the catalyst in which, of course, the carbon deposit, the outer layers of which contain the metal contaminant, is gradually burned from the catalyst particles.

Heaters 40, 41 and 42 are provided to adjust the temperature of the oil streams 23, 24 and 25 just before these streams enter into riser 26.V

We areaware of the disclosure of Serial Number 586,- 812 led May 23, 1956, now US. Patent No. 2,938,856, by George R. Hettick, and Patent 2,893,943, B. Vignovich, July 7, 1959, in which there are set forth, described and claimed fluid catalytic cracking operations which, although they resemble in some of their aspects, some of the aspects of the instant invention, are clearly distinguishable therefrom.

l Specific Example Drawing Number Conditions in Zone 50:

Cat/total hydrocarbon wt. ratio. Lbs. steam/bbl. total hydrocarbon Temperature, F., 1,140 to 1,085. Fresh oil, Percent Conversion- Contact time, seconds Medium refractory oil, bbls./hr Conditions in Zone l:

Cat/total hydrocarbon Wt. ratio Lbs. steam/bbl. hydrocarbon.. Temperature, F., 1,085 to 935 Fresh oil, Percent Conversion. Contact time, seconds... Heater 41 outlet temp., Steam p.s.i.g.), #,hr.... Least refractory oil, bbls./hr Conditions in Zone 52:

Cat/total hydrocarbon wt. ratio lbs. steam/bbl. hydrocarbon..--. Temperature, F.935 to 905.. Fresh oil, Percent Conversion. Contact time, seconds.. f Heater 42 outlet temp., Reactor 2: k

Cat./hydrocarbon wt. ratio.. Temperature, F Total Percent Conversion- Oil (23), Percent..... Oil (24), Percent-.. Oil (25), Percent... Contact time, seconds s+ L-r so un OO @om OH ONO namen @com lup to Range of 15,000 to 30,000 #/hr.

b Based on charge oil.

e 1085u F. is outlet temperature of zone 50.

.1 Range of 0-10,000 #/hr`. to vary residence time in this section to optimlze conversion.

Based on 20,000 #/hr. steam for catalyst hydration. Part of the steam (28) entering zone (5'0) is absorbed by the catalyst. 25,000 #/hr. 20,000 #/hr. leaves 5,000 if/hnior zone (51). Zone (51 has, therefore, this 5,000 #/hr. plus 5,000 #/hr. vla (28a), and this 10,000 fr/hr. steam-2-1240 bbls./hr. fresh feed to zone (51) gives thev8.1 #/steam/bbl. hydrocarbon.

f 935 F. 1s outlet temperature of zone (51).

s Range of 0'10,000 #Ihr-'.- as in (d).

f1 100 b./h. va (32) and 160 b./h` via (15).

1 Based on 10,000 #jhr. steam from zones (50) and (51) together plus 5,000 #Ihn steam vra (281;), and this 15,000 #,lhr. steam+260 bbls./hr. fresh feed to zone (52) gives the 57.5 #steam/bbl. hydrocarbon.

l 905 F. 1s the outlet temperature of zone (52).

k M ay operate Without hed level.

l Disregarding contact time in dilute phase.

In the above specific example, we have added, for simplicity, the slurry stream 32 to only the topped crude 15, which further decreases the activity of the catalyst in zone 52. This ilow affords further control on the cracking of the least refractory topped crude.

lt is seen that the catalyst activity decreases in the direction of flow of line 26 to the reactor 2. The slurry stream 32 which comprises spent catalyst and decant oil (which may or may not be very refractive) may be used at the selected loci 50, 51, and/ or 52 to adjust the activity of the catalyst, and to adjust the refractorinesses of the oils at these loci for optimum conversion of the different o1 s.

Further, additional control of conversion in zones 50, 51 and/or 52 is made by adjustment of the oil outlet temperatures from heaters 40, 41 and/or 42. In addition, steam addition via 23, 28a and/ or 2815 is also used for control of conversion in the reaction zones. That is, for a iixed charge rate, injection steam rates and slurry recycle are chosen for optimum conversion of each of the feedstock.

The changing of the quantity of injection steam to a zone changes the residence time in that zone, which affects conversion. The residence time can also be controlled or varied by using several injection points in each zone for each feedstock. Also, our invention is applicable to more than three feedstocks.

It is pointed out that required contact time for some least refractory materials may be so short that it may be necessary to inject these materials directly into the reactor 2 bed instead of the riser as shown in our figure. The most refractory stock (most difiicult to crack) is cracked with the most active catalyst, the highest reaction temperature, and the largest catalyst to oil weight ratio. (Residence time is adjusted by injection steam and feed nozzle location in the system.)

When, conventionally, the most refractory oil was catalytically cracked in the presence of the medium refractory oil, the most refractory oil was convented only about 30 percent, and the medium refractory oil was converted about 57 percent. By our invention, the most refractory oil is converted 55 percent and the medium refractory oil is converted 50 percent. Hence, our method of operation minimizes the buildup of recycle of unconverted most refractory oil which buildup is faced in the prior art, and our invention, therefore, does not have to back out the fresh feed or medium refractory oil as must be done in the conventional operation which thus loses production capacity in the conventional system.

Reasonable variation and modification are possible within the scope of the foregoing disclosure, the drawing, and the appended claims to the invention, the essence of which is that there have been provided a uid catalytic cracking or conversion operation in which hydrocarbon oils of diiferent types can be converted according to their orackability or refractoriness, as evident from the foregoing disclosure, and the drawing, and the appended claims, in the presence of a fluid catalyst, for example, a silica-alumina cracking catalyst, which, according to the invention, is preconditioned, as apparent herein, by rst treating it by using it in the presence of steam to initiate cracking of a most refractory stock which can be a paraiiinic raiiinate `resulting from the solvent extraction of a cycle oil in the system, followed by addition of virgin gas oil and/ or vacuum gas oil, in turn followed by addition of topped crude oil to the uid catalyst; and a method for additionally regulating the activity of the catalyst as it rises toward the fluid catalytic cracking reactor by providing for the introduction of catalyst slurry for its activity and/or diluted eiect, together with any one or more of the streams of oil which are added to the catalyst.

We claim:

1. In a fluid catalytic cracking operation in which a fluid catalyst mass of particles is employed and in which there are cracked in the presence of the catalyst a refractory parainic oil obtained by solvent extraction of a cycle oil formed in the system, a virgin gas oil obtained from a crude oil by fractionation of the same, and a topped crude obtained from said crude oil by fractionation of the same, the steps which comprise admixing steam and catalyst and then adding successively to the mixture of steam and catalyst the oil streams in the order mentioned under cracking conditions.

2. A process according to claim 1 wherein there is obtained upon the fractionation of products from the catalytic cracking reaction, a catalyst slurry, and wherein this slurry is added to at least one of said oil streams to assist in controlling the total catalyst activity or the dilution in the combined stream of catalyst as it moves toward the catalytic cracking reaction zone.

3. In a uid catalytic cracking operation in which a fluid catalyst rnass of particles is employed and in which there are cracked in the presence of the catalyst a refractory paraiiinic oil obtained in the system, a virgin gas `oil obtained from a crude oil by fractionation of the same, and a topped crude obtained from said crude oil` by fractionation of the same, the steps which comprise admixing steam and catalyst, then adding successively to the mixture `of steam and catalyst the oil streams in the order mentioned, then continuing the conversion of lthe combined catalyst and oil streams, obtaining a cracked product stream, separating from said cracked product stream a cycle oil, recovering from said cycle oil by solvent extraction a refractory paraflinic oil and using the last-mentioned oil as said refractory parafnic oil obtained in the system.

References Cited in the le of this patent UNITED STATES PATENTS 2,584,378 Beam Feb. 5, 1952 2,616,836 Schmidt et al. Nov. 4, 1952 2,790,753 Ackerman et al. Apr. 30, 1957 2,893,943 Vignovich July 7, 1959 2,908,630 Friedman Oct .13, 1959 2,938,856 Hettick May 31, 1960

Claims (1)

1. IN A FLUID CATALYTIC CRACKING OPERATION IN WHICH A FLUID CATALYST MASS OF PARTICLES IS EMPLOYED AND IN WHICH THERE ARE CRACKED IN THE PRESENCE OF THE CATALYST A REFRACTORY PARAFFINIC OIL OBTAINED BY SOLVENT EXTRACTION OF A CYCLE OIL FORMED IN THE SYSTEM, A VIRGIN GAS OIL OBTAINED FROM A CRUDE OIL BY FRACTIONATION OF THE SAME, AND A TOPPED CRUDE OBTAINED FROM SAID CRUDE OIL BY FRACTIONATION OF THE SAME, THE STEPS WHICH COMPRISE ADMIXING STEAM AND CATALYST AND THEN ADDING SUCCESSIVELY TO THE

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