DE2046245A1 - Fluid catalytic cracking process - Google Patents

Description

DR. BERG DIPL.-ING. STAPr

8 MUNICH 2, HIUBLESTRASSE 2O

Dr. Berg Dipl.-Ing. Stapf, 8 Munich 2, Hllblestrasse 20

Our sign 19 989

1 & Sep. 1970

Attorney file 19 989

Esso Research, and Engineering Company, Linden, H _e J./USA

Fluid catalytic cracking process

With the help of fluid catalytic cracking apparatus, the most of the gasoline and other fuels obtained. Since most apparatuses have at least several Years old are converting Orack raw materials Limits are set in fuels by the system, design and shape of the apparatus. By using of zeolites as fluid cracking catalysts the performance of many apparatus has recently increased.

V / My - 2 -

1098U / 1931

The dense fluid bed cracking process allows one flexible change of the reactor location, the temperature and the circulation rate of the catalyst and thus an adaptation to the changing refining conditions. An increased need to change what is to be achieved Products such as the highest possible yield of naphtha, heating oil, the production of low boiling points Shares for petrochemicals and for alkylation as well as seasonal fluctuations in demand Result of the need for an increased possibility of changing the fluid catalytic cracking process. Purpose of the present The invention is therefore to meet changing demands on the products and the flexibility of the fluid catalytic crack process to increase.

With the help of the present invention there is an increase or changing the conversion both in an existing fluid catalytic cracking apparatus as well as in one Cracking apparatus is possible which has at least one reactor with a transfer line.

Fluid catalytic cracking with transfer-line is a type of fluid catalytic cracking of petroleum hydrocarbons in which a finely divided catalyst is suspended together with a petroleum hydrocarbon fraction which is essentially in the vapor phase. at

1 0 9 8 U / 1 9 3 1

In a typical embodiment of transfer line cracking, the suspension moves at a gas velocity in the range between about 2.4 and 15 m / sec through an elongated reaction zone, which has a ratio of length: Has a diameter in the range from about 4: 1 to about 20: 1. A sufficient amount of catalyst is kept in suspension so that a weight ratio of starting material per hour of catalyst in the reaction zone is maintained in the range of about 20: 1 to about 300: 1. the Catalyst density in a typical transfer line or riser catalytic cracking reactor is from 0.016 to 0.16 ^ (1.0 to 10.0 pounds / cubic foot).

Transfer-line reactors can either be used for the complete conversion of a crude oil fraction, or they can can be used in conjunction with a conventional dense bed of fluid cracking catalyst. Catcrack Systems transfer-line are disclosed in U.S. Patents 2,881,129; 2,895,901; 2,902,432; 3 123 547 and 3 355 380 described. In the latter two US patents, the combination of cracking with transfer-line cracking with a dense fluidized bed and the idea of cracking different raw material fractions separately described.

1098U / 1931

Reactors with transfer-line bind for the refineries of increasing interest - since they have lean oil and catalyst residence times Which favor the active catalysts to high conversions of cracking feedstock in hydrocarbons that boil in the gasoline range without excessive coke deposition would take place on the catalyst. This is especially true for the pail of using a crystalline one Aluminosilicate zeolite as a fluid cracking catalyst. Reactors with Transfer-line are also characterized by good mixing of the feedstock and catalyst and as a result of more efficient utilization of the catalyst due to a lower amount of catalyst in the system.

In modern refineries, catalytic heating must be like that Remain flexible as possible so that the quality and quantity of the product depend on the market needs can be customized. Although the cracking with Transferline is a versatile means of meeting the market needs To accommodate this, it is a purpose of the present invention to give the method an additional degree of flexibility to rent. The method according to the present invention is both for newly constructed plants as can also be used for existing systems

In short, the present invention includes one

1098U / 1931 -5-

204-248

Process for performing fluid catalytic cracking in the presence of two cracking catalysts, such as one conventional fluid cracking catalyst and a pure, non-coated crystalline aluminosilicate molecular sieve Crack catalyst. More details of the present Invention are detailed below. The drawings are flow charts showing preferred embodiments of the present invention.

The term "conventional cracking catalysts ^11" as used here includes amorphous fluid cracking catalysts of the SiO ₂ type as well as the newer crystalline aluminosilicate zeolites which are physically bound or embedded in amorphous catalyst, with clays or with another host material so that a flowable catalyst particle is obtained.

Amorphous SiO ₂ ZAl ₂ O ₃ , SiO ₂ ZMgO and SiOgZZrO fluid cracking catalysts have been commercially available for 25 years. In general, they are made by (1) simultaneous precipitation or gelation of SiO ₂ and Al ₂ O ₃ from mixed solutions of sodium silicate and aluminum sulfate or (2) by the formation of SiOg hydrogel by reacting sodium silicate with sulfuric acid and subsequent storage of Al ₂ O _{3 produced} for example by adding aluminum sulfate and ammonia · The mixed product

• 1098 U / 1931, .. · ■ - β -

ORIGINAL INSPECTED

is then washed with water and dried. Commercially available amorphous idumosilicate fluid crack catalysts have an average particle size in the range from 70 to 80 / U.

Crack clays have also been used for more than 25 years HfttusiiL Qte sr0 £ jfoaHBende ~ clays like e.g. Bentoni t, Kaolin and Ha ^ loysA-t undergo a chemical treatment subjected to activate them for catalytic cracking. They are then put into one for liquefaction and circulation in an iluid-orrack system suitable Brought particle size.

Numerous «preparations of typical and conventional aluminosilicate and clay Craok catalysts are made by Hyland et al in Catalysis, Volume VII, 1960, pp. 1 to 86, and in the literature cited therein.

The process according to the present invention is also applicable to fluid cracking processes in which Mo-Iekulareiieb-Fluid-Oraok-Kataly9at @ ^ s are used. Due to the extremely small size and high activity of the sieves, they are not used in pure form in regenerative catalytic oracking processes with a diohtem fluidized bed. They are encased in a carrier oda ^ old amorphous 3i0 ₂ / Al ₂ 0, used catalyst and / or clay. In

1098 H / 1931 - 7 -

ORIGINAL INSPECTED

In this form, the catalyst containing the zeolite is in the form of a flowable particle and can be in its cracking effect can be controlled. Additional problems such as attrition and entrainment from the reactor and / or Regenerators are weakened.

In general, the chemical formula can be used in the present Anhydrous crystalline aluminate zeolites used in the invention, expressed in moles, as follows being represented:

0.9-0.2 Me ₂ J _n O : Al ₂ O,: XSiO ₂

where Me can mean metal cations, hydrogen and ammonia, η represents the valency and X is a number of more than 3 »for example 4 * to 14» preferably 4 »5 to 6.5 ». They crystalline aluminosilicate zeolites include synthetic crystalline aluminosilicates, naturally occurring crystalline aluminosilicates, and causticized and aged clays in which some of the clay has been converted into the crystalline zeolite. Synthetic Materials include faujasite and mordenite. Natural materials are erionite, analcite, faujasite, phillipeit, Glinoptilolite, Ohabasite, Geelinite, Mordenite and their Mixtures. Montmorillonite and kaolins can be converted into crystalline AluMOsilicates by treatment.

1098U / 1931

The cations of the zeolites, such as sodium cations, can be completely or partially by hydrogen ions, ammonium ions or metal cations such as rare earth cations, manganese, cobalt, zinc and other Group I metals to be replaced by till de · periodic table.

Preparations of fluid orracking catalysts of the carrier type are disclosed in U.S. Patents 3,329,628; 3 352 79 € j 3 410 808 and 3 140 249. With this one The type of catalyst are the zeolite crystals with a silica gel coated or embedded in it. The catalyst of the The carrier type contains 5 to 50 *, preferably 5 to 20 *, crystalline zeolite.

Certainly ··· natural «Tonaineralien can be a treatment under BOg «n, among other things« part of the material in crystalline « Transfer zeolites see below. Clays such as kaolin, kaolin oil, halloysite, bentonite and others containing silica Ton "were treated in a" white "way, as described in US Pat. No. 3,037,843 J 3,065,054 and 3,458,454 is described. The treated clays contain 5 to 50 * crystalline zeolite.

J «the Herkönalloh« flttid-Craok catalyst of the zeolite type, which contains 5 to 50 * zeolite and has an average "particle size of" or more than about 50 .mu.m, can be in

109814/1931 ~ ⁹ "

ORIGINAL INSPECTED

the method according to the invention as the first or main- '· Licher Pluid Craok catalyst can be used. The additional or second catalyst is an essentially pure, non-coated crystalline zeolite, which contains 70 to · -IOO96 crystalline zeolite and an average particle size of less than 10 / U, preferably less ale 5 / u, has · The most "preferred particle size ranges from 0.1 to 2 / U. The pure zeolite is used in very small amounts in the process to increase the cracking caused by the conventional JMuid catalyst. The preferred embodiment is the. pure sieve catalyst on the basis of a is based on a single pass and no attempt is made to recover the pure zeolite catalyst or to regenerate

In Pig. Reference number 1 refers to 1 of the drawings on a single-stage pluid catalytic oil rack reactor. at in this type of reactor, most of the cracking takes place in the dense bed and less of the conversion in the reactor feed, in the dilute phase above the dense bed and in the stripper. In the conventional implementation of the method, a Rphölhydrocarbon for mixing with the regenerated fluid-cracking catalyst is fed to the line 3 by means of the line 2. Input materials suitable for the process

1098U / 1931 - ¹⁰ -

BAD ORIQ _INAL

are tractions that boil in a range of clay 93 Ms 65O ⁰ O (aoo to 1200 ⁰ T) and are obtained by atmospheric distillation, intssphmltierung, vacuum distillation, coking, visbreaking and from mixed tractions and the like. The oil suggested by the process is generally heated to a suitable temperature in the range from 150 to 480 ⁰ G (300 to 900 ⁰ T) and preferably passed through line 3 in the vapor phase or in the mixed phase, in which the largest proportion of the feedstock, ie 60 to 99 pounds, in the vapor phase. The ratio τοη catalyst eu oil is in the range τοη 2/1 to 15/1.

The feedstock is cracked in a dense fluidized bed 4 at a temperature in the range from 370 to 57O ⁰ O (700 to 1050 ⁰ I), preferably 455 to 510 ⁰ O (»50 to 950 °?). The pressure is τοη 0.07 to 3.5 kg / cm ² (1 to 50 paig.) The conventional fluid catalyst is separated from the Tom Craok overflow by means of cyclone 5, the fluid catalyst returning to the fluid bed and the drinking Products and the »unconverted material is discharged overhead through line i. The geοrack th products are separated in the fractionation column 7. ul) he the line 8 a ole and Benainfraktion obtained.- iine keroin ^ an% fuel fraction

1098U / 183J-- - ¹¹

BATH

is obtained through line 9, fuel oil fractions and Recycle oil fractions are obtained through lines 10 and 11, respectively. A swamp fraction is through the line obtain.

A conventional fluid catalyst, the dtr regeneration is required by the stripper 13 and the line 14 "um Regenerator 15 led. The catalyst is regenerated using conventional fluid contact agents and via the Line 3 returned to the reactor

The pure, non-embedded and undiluted molecular sieve catalyst can use the Fluid Catalytic Oraok process be added at one or more suitable points in the system. In one embodiment, the pure Catalyst fed to line 3 via line 16a The advantage of this point of addition is that that the pure catalyst united with the hot, regenerated, conventional fluid catalyst under conditions good heat transfer Y is mixed, so that the sugesetste.Katalysator is heated to the same temperature as the fluid catalyst before it is heated with the linsatx material comes into contact. Another advantage of adding at this point is that the fresh and untouched feed material comes into contact with fresh and non-poisoned catalyst. The pure catalyst reacts

1098U / 1931 " ¹² "

BATH

2ÜA62A5

with the feed oil as soon as it is in with the feed the line 3 comes into contact. Because of the much smaller particle size compared to the pure catalyst the conventional fluid catalyst, the former is able to flow through the Fluid Craekv reactor into line 6 to flow. If the pure sieve catalyst is not to come into contact with the fluidized bed 4, the catalyst can the dilute phase of the fluid reactor through the line 16b can be added. Several feed lines, which are attached around the circumference of the reactor, can serve to obtain good dispersion of the catalyst. In a further embodiment, the pure catalyst added to the cracking vapors coming out the reactor via line 6 into the reaction vessel be guided. The catalyst is added through line 16c, and it can optionally be added through line 17 hot steam obtained from the reactor serve as a carrier medium for the catalyst. In another Embodiment, the pure catalyst is added to the stripper 13 through line 16d. The pure catalyst flows upward under the driving force of the stripper gas added to the stripper via line 18 by the stripper. The pure zeolite catalyst can be added to the fluid cracking system by any combination of the Lines 16a, 16b, 16c and 16d are added.

- 13 109814/1931

The position of the feed lines for the pure catalyst depends on the type of fluid cracking system and its properties of the feed, including the reflux material and the type of product desired. As a result of seasonal "requirements such as" for example after a maximum of gasoline in summer and a maximum of heating oil in winter »it may be desirable one feed point during one time of the year and another point during another season use. Furthermore, it can be advantageous to use the pure zeolite catalyst in accordance with the seasonal requirements to be added discontinuously to the products, X> aa The ratio of the pure catalyst to the oil is in the range from 0.1 to 1.0 to 0.001 to 1.0. Go out of this indicate that a very small amount of neat catalyst is used.

As the amount and particle size of the pure zeolite catalyst is very low, most of the material passes through the cyclones 5 and line 6 into the fractionation vessel 7. The lower part of the fractionation vessel has a stripper on, which is why most of the catalyst is stripped into the heavier fractions. Possibly the catalyst can be removed from all product fractions using suitable separation devices,

-H-109814/1931

In Figure 2 of the drawings, the reference numeral 21 designates a line through which a fresh crude oil hydrocarbon feed is fed to a reaction zone 22 having a transfer line. Suitable feeds for the process are fractions which ^{boil in the range from 90 to 65O 0} O (200 to 1200 ⁰ P) and are obtained by distillation at atmospheric pressure, deasphalting, vacuum distillation, coking, visbreaking, solvent extraction and mixed fractions. The fraction known as gas oil is a preferred feed. The oil feed to the process is generally heated to a suitable temperature in the range of 150 to 500 ⁰ O (300 to 900 ⁰ F) and is preferably introduced via line 22 into the vapor phase or into the mixed phase, in which the greatest proportion of the feed a, ie 60 to 99 # i, is in the vapor phase.

The feed is mixed with hot catalyst withdrawn from regenerator 23 via line 24 will. In this particular embodiment, the line 24 is closed with the aid of a suitable valve arrangement (not shown) divided into two lines, 25 and 26, so that the early feed and the return material are drawn separately. Am mixture of the catalyst Line 25 and the etching material from line 21 is in the line 22 to transfer-line conditions catalytically

1Q98U / 1931 - 15 -

cracked. Preferred conditions are temperatures in the range from 260 to 54O ⁰ O (500 to 1000 ⁰ F), pressures in the range from 0.07 to 3.5 kg / cm ² (1 to 50 psig.), A gas velocity in the range of 2, 4 to 15 m / sec (8 to 50 feet / second), a catalyst density in the range 0.016 to 0.801 g / cnr ⁵ (10 lb / ^ft.-5), and a weight ratio of feed to catalyst in the range of 20: 1 to 30Oi1. The transfer-line reactor has a length to diameter ratio in the range of about 4: 1 to about 20-1.

The rate of conversion in a transfer-line reactor is very high and ranges from 0.5 to 10 seconds. The cracked overflow and catalyst are over the line 22 led into the cyclone 27. In the in Fig.2 In the embodiment shown in the drawings, reference numeral 28 denotes a sealed bed reactor stripper of liquefied catalyst 29, a dilute phase or settling zone 30 and a stripper zone 31 · The cyclone 27 separates the catalyst and cracked overflow, with the catalyst down over device 32 is passed into the tight bed 29. The cracked overflow runs through cyclone 33 into line 34 for discharge to a product fractionation device 35.

In this embodiment, the Oracle is done in one

1098U / 1931 - 16 -

separate way. The reflux material from the fractionation device 35 below the deck device is fed via the line 36 to the riser pipe 37. Hot, regenerated catalyst from lines 24 and 26 is mixed with the reflux material. The riser 37 can be of any desired length. In one embodiment
becomes 5 to 50% of the cracking of the reflux material in the

^ Riser 37 and the further cracking carried out in a tight bed 29. In this way, riser 37 can operate in a manner similar to a transfer line by maintaining conditions as described for line 22 in line 37. The cracked overflow from the riser 37 and
the dense bed 29 overflows from the reactor 28
Zyklon 33 and the line 34 for fractionation and recovery of gas, petrol, kerosene, heating oil, reflux and
Residue fractions. The one separated from the overflow

The catalyst is returned to the dense bed 29 from the cyclone 33. The liquid catalyst from the transfer line and the dense bed is passed through the stripper 31 in which it is introduced through the line 38
Steam is brought into contact. The stripped catalyst is then passed via line 39 to regenerator 23 to be regenerated in a conventional manner.

- 17 1098U / 1931

In one embodiment of the present invention, a portion of the fresh or virgin feedstock in line 21 with reflux material in line 36 or vice versa by actuating the valve 40 in the lei device 41 and the valve 42 in the line 43 vermisehii will.

The above description relates to an embodiment of a combination of transfer-line and Jluidt-Catalytic-Oraoking with a dense bed in the presence of a conventional, liquefied Oraok catalytic catalyst. The way this system works is barked up and increased by adding pure crystalline aluminum silicate zeolite, which has an average particle size of less than 10 / U at a suitable location. For example the pure molecular sieve zeolite can duroh the line 44a, 44b, 44c and / or the line 44d issued will. The advantages of adding the pure molecular sieve via line 44a are that there is one good mixing and heat transfer is achieved with the hot, regenerated and liquid catalyst that enters the transfer line 22 through the line 25, and that the fresh and coke-free pure sieve catalyst contacted the unreacted and untouched feedstock. The line 44b is used to transfer the separated Reflux material in line 37 with the coke-free,

ι 1098U / 1931 - ¹⁸ "

pure molecular sieve contact that is in the line 26 for mixing and contacting with the reflux material with hot, regenerated, liquid catalyst is mixed. In another procedure, the pure molecular sieve is added to the partially geo-okened material in line 22 by means of line 44o. The advantage of introducing the second catalyst at a point near the end of the transfer-line reactor is that the orracking process takes place in one place an ausätaliohe stimulation is conferred in which a conventional liquid catalyst has decreased in activity due to the accumulation of coke. A the line 25, 22 or 26 added pure catalyst flows duroh dls cyclones in the Heaktorstripper 28 and becomes with the geeraokttn overflow from the transfer line 22 and the reactor stripper 28 in line 34 received. The pure catalyst can also by means of the line 44d of line 34 are sugesetst. This place of addition has the gate part that made contact after the liquid catalyst has been removed from the Oraok overflow. The lower foil de · Iraktioniergefäß «has a stripper, whereby the largest part of the roinon molecular sieve catalyst into the heavier ones frak-feionon is stripped off «if necessary this can Catalyst duroh suitable · Separation devices from each Product fraction are separated

1098U / 1831 - ¹⁹ -

ν BAD ORIGINAL

example 1

As a specific example of a liquid catcracking process according to the present invention, the following information relates to a plant that is charged with 10OM B / D of fresh gas oil. About 5000 to 10,000 kg / min (5 to 10 tons per minute) of a conventional regenerated amorphous SiOp / AlpO catalyst containing 13% Al ₂ O is mixed with the feed in line 3. About 6.7 to 11.2 kg / min (15 to 25 lb / min) of a rare earth exchanged synthetic faujasite is fed to line 3 via line 16a. The conventional catalyst in line 3 has 70% particles in the range from 40 to 80 / u. The pure zeolite catalyst has 90% particles in the range from 0 to 10 / u. The residence of the conventional catalyst in the dense bed 4 is 1 to 4 minutes, the residence time of the pure zeolite catalyst is less than 10 seconds, and when the zeolite catalyst is added, the conversion of the gas oil is increased.

The process according to the present invention is applicable to all types of liquid cracking systems which have a dense bed of a liquefied catalyst. Typical dense beds have a catalyst density of 0.16 to 0.56 g / cm ⁵ (10 to 35 lb / cu.ft.). Systems in which the reactor is positioned above the regenerator

1098U / 1931 -20-

"is brought, and systems in which the reactor and the regenerator enveloped by a single envelope are encompassed by the present invention.

Example 2

As a specific example of a transfer-line oil cracking process according to the present invention, the following information relates to a plant which is charged with 1OM B / D of a fresh gas oil and 3M B / D of a reflux material having a boiling range of about 260 to 40O ⁰ C comprises (up to 75O ⁰ F 4-80). About 8500 kg / min (8.5 tons per minute) of a synthetic> ■ faujasite regenerated in a conventional manner and exchanged with rare earths, which is encased in a matrix of SiO ₂ ZAl ₂ O, is discharged from the regenerator via line 24 23 from

; drawn. The liquid catalyst in line 24 has

ί 80 * particles ranging from 40 to 80, u on. With help A suitable valve arrangement will provide about 6000 kg / min (6 tons per minute) of conventional cracking catalyst • transferred via the line 25 into the transfer line 22 and about 2500 kg / min (2.5 tons per minute) of the conventional Catalyst · Passed into riser pipe 37 via line 26. Approximately 9 »45 kg / min (21 pounds * per minute) one Pure, uncoated and rare earth exchanged synthetiiühea faujasiti are delivered via line 44a line 25 and from there to line 22

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■ 1 »lit» 141

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increase the cracking in the transfer line. The pure zeolite catalyst has 90 # particles in the range of 0 up to 10 / rev. The Craek overflow and catalyst fee * pass the transfer line in a period of about 2 seconds. A certain, deliberate slip baw. Back mixing of the liquid catalyst is in the interest of maximum contact with the feed and any one thereof resulting maximum conversion formed. With the addition of the pure zeolite catalyst, the conversion takes place elevated.

The method according to the present invention is applicable to all types of liquid cracking systems in which one or more transfer-line cracking zones and / or Riser crack zones are used. Bas system can have a dense bed of any liquid catalyst desired Have volume in order to obtain a small or substantial amount of cracking. The pure molecular sieve catalyst can be added to the system at any desired point where this addition is advantageous is to increase or change the crack conversion

The advantages of the present method are from a cost point of view Interesting because a very small amount of catalyst is used to operate the Jluid-Cracking plant to improve · Regardless of the type and

1098U / 1931 - 22 -

The age of the fluid catcrackers are only minor structural Changes to the plant are necessary in order to create a device for adding the pure zeolite catalyst. With a negligible Sigmaren or very modest Increase in the burning function of the regenerator «the conversion of the etching material is increased

- 23 -109814/1931

Claims (1)

• a · » ¹ € 23 - Patent claims: Cracking process for a crude oil hydrocarbon fraction, characterized in that this fraction brings into contact with a liquid cracking catalyst under cracking conditions in a liquid cracking zone » which has a mean particle size τοη at least 40 / U, and increases the Oraek process in the liquefied Orack zone by nan at least part of the mentioned fraction contacted in the presence of a second catalyst, which is a pure, crystalline aluminosllicate zeolite with an average particle size τοη less than 10 / U contains 2. The method according spoke 1, characterized in that that the liquefied Craok zone has a dense bed of catalyst. 3. The method according spoke 1, characterized in that that the liquefied 'Vmok-Zon · has at least one transfer line crack reactor. 4- «Method according to claims 2 or 3, thereby characterized in that the second catalyst is a middle one Particle size in the range τοη 0.1 cis 2 / U. - 24 -109814/1931 _BAD 2 CH G 2 A 5 5. The method according to claim 2 or 3, characterized in that the liquid catalyst 5 to 409ε one has faujasites exchanged with rare earths in a matrix. 6. The method according to claim 2 or 3, characterized in that the liquid catalyst is an aluminosilicate cracked clay is the 5 Ms 4096 of crystalline aluminosilicate zeolite contains. 7. The method according to claim 2 or 3, characterized in that the second catalyst is a crystalline Aluminosilicate zeolite is made using an ion exchange process has been subjected to hydrogen, ammonium, rare earths, magnesium, calcium, aluminum, Contains zinc, platinum and / or palladium. 8. The method according to claim 2 or 3, characterized in that the second catalyst is a naturally occurring Contains crystalline aluminosilicate molecular sieve zeolites. 9. The method according to claim 2 or 3, characterized in that the second catalyst prior to contacting the fraction with regenerated, liquid cracking catalyst mixed and melted in the heat. 1098U / 1931 - 25 - 10. The method according to claim 2, characterized in that that the second catalyst is added to the dilute phase of the liquefied cracking zone " 11. The method according to claim 2, characterized in that that the second catalyst is added to the essentially cracked fraction in the recovery section of the cracking zone, 12. The method according to claim 2, characterized in that the second catalyst is the stripping part of the cracking zone is admitted. 13. The method according to claim 2, characterized in that it contains a single-stage, liquid catcracking process. 14 »The method according to claim 2, characterized in that that the second catalyst is the lower one in the direction of flow Part of the transfer-line cracking zone is added. 15. The method according to claim 3, characterized in that separated and fresh Binsatzmaterial in one Transfer-line is cracked and the crack overflows in the dilute phase of a reactor stripper is passed. 16. The method of claim 3 _t characterized in 1098 U / 1931 -26- that the separated reflux material partially in one Riser crackers are cracked in direct communication with a dense bed of liquefied catalyst and further cracking the reflux material in the dense bed. 17. The method according to claim 3, characterized in that that contacting at least a portion of the fraction in the presence of a second catalyst in the transfer line is made. 109814/1931 Blank page