JPS60158290A - Fluidized catalytic cracking process - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an improvement in a hydrocarbon conversion process in which a catalyst is contacted with a hydrocarbon feed in a fluidized bed reactor.

BACKGROUND OF THE INVENTION Fluid contact processes are well known. The cracked hydrocarbon vapors are conducted from the reaction column to various product rectification columns where the hydrocarbon mixture is separated into fractions. Some amount of catalyst is normally carried with the hydrocarbon vapors into the rectification column. This catalyst tends to accumulate in the fractionator in the heaviest hydrocarbon fraction contained in the reactor effluent.

It is known to simply recycle this heavy oil, commonly referred to as slurry oil, back to the reaction column in order to reduce the loss of relatively expensive FCC catalyst from the plant. Unfortunately, this slurry oil is highly aromatic and relatively heat resistant or inert to the conditions under which it was created in the FCC reactor. Recirculation of slurry oil to minimize catalyst loss reduces the tendency for highly aromatic slurry IJ-oil to pass through the FCC reactor intact (unconverted) and accumulate. This causes the amount of slurry flow to increase.

Separating and recycling catalyst particulates from slurry oil is disclosed in U.S. Pat. No. 3,338,821;
No. 2,675; No. 4,285,805: and No. 4,3
No. 45,991, it is now a standard method. All of these patents teach recovering and recycling catalyst fines produced in the FCC reactor to the reactor to reduce catalyst loss.

Slurry oils can be cleaned by passing these oils through an electric filter, as disclosed in U.S. Patent No. 3.
．． No. 928,158.

U.S. Pat. No. 4,059,498 teaches an improved device in which a central tubular electrode extends downwardly through the filter bed and an outer vertically porous cylindrical electrode is arranged concentrically with respect to the central electrode. Given the attractive liquid flow,
Allows for increased flow velocities compared to longitudinal flow.

Constraint coefficient (ContttraJnt) ranging from 1 to 12
Improvements in process efficiency have been made available to FCC operators through the development of zeolites characterized by the characteristics of the term and the methods for their determination are described in applicant's UK Patent No. 1.446,522. It is said that it is something that can be used for many people. The term “zeolite” used here
is porotectosilicates (porotectosilicates)
icates), ie porous crystalline silicates containing silicon and oxygen atoms as the main constituents. Other components will be present in small amounts, usually up to 14 mole % and preferably up to 4 mole %. These ingredients include aluminum, gallium, iron, chromium, boron and the like.
Aluminum is preferred and is used herein for illustrative purposes. Minor components may be present separately or in mixtures.

Constraint coefficient CCI) values for some typical materials are as follows:

I ZSM-40.5 ZSM-58.3 ZSM-118.7 ZSM-122 ZSM-239.1 ZSM-354.5 ZSM-382 TMA Offretite 3.7 Clibutyrolite 3.4 H-Zeolon (Mordenite) 0.4 REV 0.4 Amorphous Silica-Alumina 0.6 Erionite 38 Certain crystalline zeolites are described in the aforementioned British Patent No. 1,446.
If the same zeolite is found to have a restraint coefficient in the approximate range of 1 to 12 under one of the combinations of conditions that fall under the test definition described in No. 522 of Even if a zeolite exhibits a constraint coefficient outside the approximate range of 1 to 12 under other conditions, it shall be included in the definition of zeolite of the present invention.

The novel class of zeolites defined herein has the structure W
-5, ZSM-11, ZSM-5/ZSM-11 intermediate type, ZSM-12, ZSM-23, ZSM-35, ZSM
-38 and ZSM-48, which are respectively exemplified by U.S. Pat.
, No. 979: No. 4.229, No. 424: No. 3,832,
No. 449: No. 4,076,842: No. 4. OX 6,
No. 245: No. 4,046,859; and No. 4.377
, 497, based on X-ray data.

The present invention is directed to the use of such zeolites in which the molar ratio of silica to alumina (referred to as the silica/alumina ratio or SiO2/AltOs ratio) is essentially unlimited. When referring to the above-mentioned patents, the range of crystalline zeolites disclosed should not be construed as having the specific silica/alumina content discussed therein; such zeolites today are Zeolites that can be free of upper alumina, have the same crystal structure as the disclosed material, and contain trivalent lattice elements other than aluminum are possible and useful. Alternatively, it should be taken into account that it may be preferred in certain applications.

ZSM-5 is a preferred catalyst because it is very active. Successful FCC processes can use catalysts containing relatively small amounts of ZSM-5 in an amorphous base such as silica, alumina, or silica-alumina.

One of the advantages of the ZSM-5 material, its high activity, poses considerable operational problems. Its high activity, ZSM-5
By including ZSM-5 in the amorphous pace, the ratio of ZSM-5 to amorphous material is fixed during mildening. ZSM-5 in an FCC reactor in operation by the addition of additional particulate matter containing an increased amount of ZSM-5 compared to pure ZSM-5 or the equilibrium catalyst in the FCC reactor.
The content can be increased to some extent. Unfortunately, there is no way to remove the ZSM-5 catalyst other than removing the catalyst inventory (all catalyst loaded) from the reactor and replacing it with a different FCC catalyst.

Another operational problem with ZSM-5 loaded into an amorphous matrix is that the deactivation/reactivation properties of ZSM-5 and the amorphous material are different. ZSM-5 material is relatively stable in the FCC reactor in terms of activity. ZSM
-5 requires very little regeneration. The amorphous material deactivates rapidly after only a few minutes of operation due to coke deposition. FC is the only way to restore the activity of amorphous substances
C. The above coke is incinerated in a regeneration tower. Regeneration of amorphous materials tends to prematurely degrade the ZSM-5 catalyst passing through the regeneration tower, and the addition of ZSM-5 to the FCC reaction tower is necessary to replenish the ZSM-5 damaged by the regeneration operation. The addition of finely divided zeolite additive accelerator powder is taught for this purpose. This reference is “
The additive accelerator can also be introduced and/or recycled through the recycled feedstock.'' Column 3, No. 28-
See line 29. Since the additive is sized such that it coats the catalyst, it is immobilized on the catalyst and behaves as an FCC catalyst. Recycle from the main rectifier bottoms will be recycle of heat resistant slurry oil in addition to additive recycle.

Petroleum refinery engineers do not have an economical and effective means to reduce the ZSM-5 content of FCC reactor columns. ZSM
It was possible to add -5 quickly, but it was not possible to remove it. It has been possible to deactivate ZSM-5 naturally in the regenerator, but premature deterioration of the catalyst is an expensive method of removing its catalytic activity. Therefore, the ZSM-
There has hitherto been no completely satisfactory method of controlling the 5 content. Operations using ZSM-5, an amorphous pace, typically result in premature deterioration of the ZSM-5.

Features of the present invention> Now, the ZSM-
It has been found that it is possible to increase or decrease the amount of 5 catalyst. A method has also been found to keep the active ZSM-5 catalyst outside the harmful environment of the catalyst regeneration tower.

According to the present invention, the cracked raw material is heated in the reaction column at 30 to 80%
contacting a cracking catalyst having an average particle size of the μ door and a pore size sufficient to allow at least a majority of the cracked feedstock access to the cracking site, and the catalyst is continuously withdrawn from the reaction column and regenerated; In a cyclic, regenerative fluid catalytic cracking process in which the hydrocarbon effluent is continuously withdrawn from the reaction column and rectified, the hydrocarbon effluent is returned to the reaction column and has a restraint factor ranging from 1 to 12. A catalyst consisting of crystalline zeolite and having an average particle size of 3 to 30 μm is added to the reaction column and as entrainment in the effluent at at least 50% of its addition rate. A fluid catalytic cracking method is provided, which is characterized in that:

In a preferred embodiment, the added catalyst is withdrawn by entrainment in the effluent at at least 90% of the rate of addition thereto, and the amount of the added catalyst in the reaction column is such that the amount of the added catalyst in the reaction column exceeds the decomposition rate in the reaction column. 0.1 to 05 wt% of the amount of catalyst. Typically, the added catalyst is recovered from the waste stream in the effluent and recycled to the reaction column, and at least 99 wt% of the added catalyst present in the reaction column can be recycled added catalyst. I can do it.

Cracking catalysts usually consist of 5 to 50 iDt% of synthetic faujasite uniformly dispersed in an inorganic oxide matrix, while additive catalysts usually consist of a zeolite with a structure of zeolite Z; 5M-5 in an amorphous binder. 10
It consists of a composite of 40wt% to 40wt%.

Accordingly, the present invention provides a fluidized contact system in which a feed stream is fed into a fluidized bed reactor having a fluidized bed of equilibrium catalyst to produce cracked products, and the converted feed stream is withdrawn from the process as a product. The conversion process is characterized in that an entrainable catalyst additive is added to the fluidized bed and a majority of the entrainable additive is removed with the product removed from the fluidized bed reaction zone. A fluid catalytic conversion method is provided.

In a second aspect, the present invention involves feeding a hydrocarbon feedstock and an entrainable catalyst additive to a fluidized bed reactor having an equilibrium fluidized catalytic cracking catalyst to produce a vaporized catalytic cracking product. removing from the FCC reactor a vaporized product containing at least 90 wt% of the entrainable catalyst additive; recovering at least a portion of the entrainable catalyst additive from the vaporized product; and recycling at least a portion of the entrainable catalyst additive to the reaction column.

In a more limited aspect, the present invention provides a fluidized bed reactor with a hydrocarbon feedstock and a hot (from a source as defined below)
Feed the regenerated equilibrium catalyst: Add fresh entrainable catalyst additive and recycled entrainable catalyst additive (from a source specified below) to the reaction column: Converting the hydrocarbon feedstock to hydrocarbon products in a fluidized bed: removing the equilibrium catalyst from the reaction column and regenerating the same in an oxygen-containing regeneration zone to obtain the regenerated catalyst as a regenerated catalyst; recycled as the hot, regenerated catalyst to the FCC reactor; removing from the reactor a reactor effluent vapor stream comprising at least 50 wt% of the hydrocarbon product and the entrainable catalyst additive; : separating and rectifying the reactor effluent vapor into a relatively heavy liquid product stream containing a plurality of relatively light hydrocarbon products and the entrainable catalyst additive; recovering at least 90 wt% of the entrainable catalyst additive contained therein from a target heavy liquid stream and recycling the additive to the FCC reaction column. A method for fluid catalytic cracking of hydrocarbons is provided.

Problems to be Solved by the Present Invention> The present invention solves two independent problems. The first problem solved was that the ZSM-5 catalyst, or other entrainable catalyst additive, could be added continuously to the catalyst contained in the fluidized bed reactor, and the equilibrium catalyst could be removed from the reactor. can be taken out quickly and independently (irrespectively).

The effect of adding catalyst additives can be made permanent by continuous addition.

The second problem solved by the present invention is the application of Z:5M-5 catalyst or other entrainable catalyst additives to high temperature F.
It can be recovered and recycled to the reaction tower without passing through the CC regeneration tower. Avoiding FCC catalyst endogenous columns prevents premature deterioration of the catalyst additive.

Main process parameters king! ’ process parameters are explained one by one.

Reaction columns/regeneration columns These are of conventional type. The FCC reactor may be entirely dense phase fluidized bed, or may operate entirely with riser cracking, with a dilute phase process, or some mixture of both modes of operation.

The FCC regeneration tower can be a single rich bed or two rich beds connected by a lean phase transport riser that connects to a second rich bed within the regeneration tower. The regeneration tower may be operated in a co afterburning manner or may be operated to produce substantial quantities of co. In the practice of the invention, it is most preferred if the regeneration tower is operated relatively hot:
This is normally associated with co-poor turbine operation. The hot catalyst promotes rapid deactivation of Yoshio FiZSM-5 material.

Equilibrium CatalystEquilibrium Catalyst, which consists of the bulk of the catalyst in the fluidized bed reactor, whether a conventional fluidized bed or FCC catalyst, either amorphous or crystalline, or a mixture of both. good. The particle size distribution of the catalyst is required to have good flow properties in the reaction column. By way of example, but not by way of limitation, a good equilibrium catalyst has the following properties:

Particle Density, g/cc 1.42 Light Loading Density, g/cx= , 99 Average Particle Size 5trut 74 Size Distribution Diameter -20- 0-404 40-6015 60-8045 80+ 37 Entrainable Catalyst Acceptable Catalyst Additives can be added to the fluidized bed reactor and removed with the vaporized reactor effluent. The exact size of the entrainable catalyst additive will vary depending on the operating conditions within the reactor and will be influenced to some extent by the size of the equilibrium catalyst and the efficiency of the cyclone used to return the majority of the equilibrium catalyst to the reactor. will receive it.

A preferred additive is ZSM-5 neat or dispersed in an amorphous base. In the practice of the present invention, relatively concentrated ZSM-5 material, such as typically 10 to 5 (hc+
Most preferably, t% of ZSM-5 material is added as an entrainable catalyst additive. In most common FCC reactor columns with conventional equilibrium catalysts, entrainable catalyst additives with average particle sizes of 3 to 30, and preferably 5 to 20 micrometers will give good results.

The retention time of the entrainable catalyst additive is approximately 10 times longer than the gas residence time.
It will vary between. Typically, the entrainable catalyst particles are swept together with the gas, so the residence time of the entrainable catalyst particles will be on the order of 100 to 200% of the residence time of the gas in the reaction column.

One of the further advantages obtained by the practice of the invention is that, due to its small particle size, the entrainable added catalyst, for example in the reaction column, has a disproportionately large effect (relative to its amount). It is to be. Even when operating in a non-recirculating, single-use mode of operation, the practice of the present invention makes greater use of ZSM-5 (than traditional methods) due to the highly comminuted state of ZSM-5. ing.

If ZSM-5 is an entrainable additive, it is desired to have the following composition and properties.

Suitable Acceptable ZSM-5 content 25% 5-100% chemical composition S”2 94% 10-100% Alton 6% 0-10% Particle density □, 4Qg/cc.

Particle size distribution 0-20ttrttr 7B, 6% 20-40mm 21.4% Average particle size 4.2mm 3-30° The main rectifier rectification equipment is of the conventional type. Any commonly used method of recovering valuable products from the materials contained in the reactor effluent can be used. Typically, the reactor effluent is cooled, compressed, and sent to various absorption and rectification columns. The heaviest substances contained in the reactor effluent are usually transported to a large rectification column,
It is typically recovered as a bottoms stream from the main rectification column.

It is preferred that the entire entrainable catalyst, or a portion thereof, be returned to the reactor or mixed with the reactor feed.

Recycling the catalyst alone or the liquid stream containing the catalyst in an increased concentration may be acceptable and may be preferred from an economic standpoint of a given arrangement ρ1.

The catalyst can be recovered from the slurry oil by filtration, standing, addition of an anti-solvent (precipitant), or other known means of separating fine powder from liquid.

It is preferable not to simply recycle, for example returning the main rectifier bath components to the reaction column. The FCC
It tends to create a heat-resistant slurry oil that is difficult to break down in equipment. Such operation also recycles both the entrainable additive and the FCC catalyst carried away from the FCC, and in some cases it is preferable to preferentially recycle the entrainable additive. .

It is also within the scope of this invention to fractionate, ie separate, large particles from small particles by staged filtration or other conventional methods. In this way, ZSM-5
, or other desired catalyst additives, can be recycled to the reactor without sending other catalyst 4R particles or main rectifier bath components to the reactor.

It is also possible to recover the zsht~5 catalyst or other entrainable catalyst additives using multistage cyclone separators, baghouses, electrostatic precipitators, or similar equipment. In this method of operation, recovery and recycling of entrainable catalyst additives will occur upstream of the product rectification column. The disadvantage of this type of operation is that it requires some additional capital expenditure, but in new plants a multi-stage cyclone can be installed to accommodate the 188 M- It would be cheaper to recover all of the entrainable particles of 5 and recycle them to the reactor rather than suffer from the problems caused by large amounts of slurry oil recirculation. Multi-stage cyclonic separation of fine particles entrained in the reactor effluent vapor also serves the desired purpose, i.e. entrainable without feeding the JZSM-5 material or other entrainable additives to the regeneration column. Recirculation of ZSM-5 to the reaction column could be achieved.

Once the additive has been recovered, additional treatments can be carried out to restore the lost activity, for example by burning off the coke deposits under milder conditions than are done in the main regenerator. It is possible to do so.

A preferred method of recovery of entrainable catalysts is electrostatic filters, such as U.S. Pat. No. 3,928,158 and U.S. Pat.
No. 9,498. US Pat. No. 3,923,158 describes an electrostatic filter in which an electrostatic gradient is imposed across a bed of glass beads. Liquid flows through the bed when an electrostatic gradient is imposed across the bed. The solids are deposited on the filter bed at the point of contact with the glass beads. The filter can be repeated and easily reconditioned for further use by backflushing.

[Brief explanation of drawings]

The invention will be further explained using the accompanying drawings. Fresh raw material enters the reaction tower via line 1. Raw materials are on line 2
mixed with the heavy recycle stream inside. Catalyst additives can be added from two sources, fresh in line 3, recirculated with the heavy recycle stream in line 2, or both hot. Catalyst additives can also be added to other parts of the plant, as long as the additives ultimately enter the reaction column. The regenerated catalyst in line 11 is mixed with the incoming feedstock at the base of riser 5 of reaction column 4. Catalyst and reaction tower outflow #m
Steam is discharged from the riser reactor tower 5 via a discharge device 6, schematically shown as a short length of pipe with a downwardly directed discharge, although a cyclone may also be used. The equilibrium catalyst that has fallen to the bottom of the reaction column 4 forms a rich bed of catalyst 7, while the entrainable catalyst additive is removed along with the reaction column effluent vapor via line 13. The illustrated riser reactor is but one example of a suitable reactor. A single concentrated bed reactor, or a series of fluidized bed reactors, and erupted bed reactors, or moving bed reactors can also be used. All of these reaction columns are operated using equilibrium catalysts and all benefit from the addition of an entrainable catalyst additive. The spent equilibrium catalyst is removed from the rich bed 7 via line 9 and fed to a conventional regeneration column 8. Air, or oxygen-containing gas or other regeneration fluid, is added to the bottom of the regeneration tower 8 via line 10. Flue gas is removed via line 12 and regenerated catalyst is removed via line 11. Reactor effluent vapor in line 13 is passed to main (rectification) column 14. Different products will be recovered depending on the feedstock and catalyst. A typical mixture of products obtained when oil is fed into an FCC unit is shown, but should not be limited thereto. The overhead fraction recovered from main rectification column 14 is wet gas in line 16. Light cycle oil (L i ghtCγc4740il abbreviation “l1CO”
″) is taken out via line 20. Heavy cycle oil (
The heavy t41cle oil abbreviation W''ECU is removed via line 22 or via line 23 if mixed with recycle additives and recycled to the reaction column. The main rectifier bottoms stream is removed via line 23. 24'a- is drawn off and fed to an electrostatic filter 26 where a heavy fraction rich in catalyst fines and entrainable catalyst additives is recovered via line 27 and via line 32. It is recycled to heavy cycle oil line 23 and from there sent via line 2t'' to mix with fresh feedstock. A portion of the main rectifier bottoms is passed through line 30't to a clarified slurry oil.
il (abbreviated @C8O') from the process, while the remaining portion is returned via line 28 to the bottom of the main rectification column. Catalyst fines and a portion of the entrainable catalyst additive are removed from the process via line 34. Although a recirculation operation is shown in the figure in which the entrainable catalyst additive is recycled, it is possible to operate in a single flow operation with no flow in line 32. The optimum amount of recirculation versus new addition of entrainable catalyst additives may be determined based on local economics. Generally, large slurry streams are undesirable because they carry large amounts of refractory material into the reaction column. Operations with single-stream entrainable additive addition result in higher costs for catalyst additives. In general, if the cost of entrainable catalyst additives is relatively high, the amount of catalyst fines produced during normal operation is relatively small, and the size of the slurry oil stream produced is relatively small, recirculation is recommended. would be the most attractive. Optimum Embodiment> The present invention is applied to i o o, o o o barrels (15
8,987 frL”) and 400 tons (406,42
When operating in an FCC plant designed to have 0 #), it operates with 200 bonds (90,72 #) of catalyst additive added daily. The catalyst additive has the following physical properties: Preferred ZSM-5 content 25% Chemical composition Sin! 949 Altos 6X Particle density 1.40 fl/ω Particle size distribution 0-20m 78.656 20-40X 21.4X Average particle size 4.2 It is then pumped to the plant as a slurry in the light cycle oil stream. It will be done. The amount of recycle additive in the recycle catalyst stream from the main rectifier bottoms is 12,500 bonds (
5,670 kg)/Ay. Recirculation of the heat-resistant slurry oil can be minimized because an electrostatic filter is used to separate recirculated additives from the slurry oil. Preferably, at least 90.96% of the slurry oil is removed from the process while at least 90-99% of the additive is recycled. The riser feed is a catalyst composition containing almost all 25 wt 96 of ZSM-5 with recirculation from the main rectifier bottom. The amount of ZSM-5 going to the regeneration tower should of course be minimized, but a small amount will pass through the regeneration tower. Exemplary Embodiments The table below compares the prior art process, i.e. without entrainable ZP; is the calculated value of the product distribution obtained. Prior art Invention conversion rate 632 67.0 6&5 67.3MCB
IZ9 10.8 1Z7 1oJ3LCO<680”
F 23.9 22,2 23.8 22.10903
16) (360℃) (196℃) C47,511,6&0 123 Cs 44 7. 'l 50 &7 C7 or less Story 3.9 44) 45 Coke 4747 Total 10α0107.610 (B) 10&0 latent alkylene) 20!5 233 Required external IC411,01fu0 Prior art Invention light hydrocarbon He 0-03 0 -09 0-04 0-12HvS
0-12 0-04 0.12 0-04011.1
8 1-36 1-36 1-57C 1.23 1
．． 48 1.48 1.70 to'2 0-89 0-9
7 1-03 1-12Cs 1.08 1.93 1
-18 2.1103- 3.32 5.75 3.8
1 6.59NC, 1,201,861,231,91
1C42,103,372,033,25G, -4,2
06,334,717,10M+0 79.5 79.
9 M+0 83.1 83.8 A feature of the present invention is a method of altering catalyst properties in an FCC reactor column without changing the catalyst inventory and without exposing the entire catalyst inventory to the conditions of the FCC regeneration column. was given to oil refinery engineers. In the case of ZSM-5 additives, the high activity and coke resistance of ZSM-5 can be achieved without exposing the ZSM-5 to the harsh conditions practiced in modern CO poorer-burning regenerators attached to FCC units. It is possible to use it. precisely balanced (catalyst)
If the ZSM-5 catalyst were added in a moving manner as shown in FIG. Extremely high Z
Would require an SM-5 make-up ratio. In contrast, implementation of the present invention allows +yc
About n of ZSM-5 catalyst required for make-up (replenishment) against rapid deactivation of ZSM-5 in the regeneration tower
Or add only pigeon and add 1! ;P; It is possible to operate an FCC reaction column in which a large amount of M-5 catalyst is present. [Brief Description of the Drawing] The drawing is a schematic flow sheet of an FCC device having a reaction tower, a regeneration tower and a main rectification tower. Procedural amendment (method) February 1, 1985 Manabu Shiga, Commissioner of the Patent Office1, Indication of the case, Patent Application No. 274264, filed in 1932, 2, Name of the invention Fluid catalytic cracking method 3, Person making the amendment Relationship to the case Name of patent applicant Mobil Oil Corporation 4, Agent 07 Address Akasaka Taisei Building, 1-18 Akasaka, Minato-ku, Tokyo (
Telephone: 582-7161) Contents of amendment 6 to the handwritten specification attached to the application

Claims (1)

[Claims] 1. Contacting the cracked feedstock in a reaction column with a cracking catalyst having an average particle size of 30 to 80 μm and a pore size sufficient to allow at least a majority of the feedstock components access to the cracking site; Then, the catalyst is continuously extracted from the reaction tower and regenerated,
In a recirculating regeneration type fluid catalytic cracking method in which the hydrocarbon effluent is returned to the reaction tower and then continuously extracted from the reaction tower and rectified, it contains crystalline zeolite with a constraint coefficient in the range of 1 to 12. a catalyst having an average particle size of from 3 to 30 μm is added to the reaction column and is entrained in the effluent and withdrawn at a rate of at least 50% of the rate of addition. Disassembly method. 2. The added catalyst is entrained into and withdrawn from the effluent at a rate of at least 90% of its addition rate. or the method described in paragraph 2. 4. The method according to any one of claims 1 to 3, wherein the added catalyst is recovered from the entrained state in the effluent and recycled to the reaction column. 5. The process of claim 4, wherein at least 99% by weight of the added catalyst present in the reaction column is recycled added catalyst. 6. One of the rectification products is a relatively heavy liquid stream containing the majority of the catalyst entrained in the effluent. Method. 7. The method according to claim 6, wherein the reading fluid is slurry oil. 8. The method according to claim 6 or 7, characterized in that a stream contains the catalyst. 9. A method according to any one of claims 4 to 7, wherein the catalyst is recovered by separation from the hydrocarbon products. Claim 9 in which separation is performed by additionally using an electrostatic filter
The method described in section. (2) The method according to claim 9, wherein the separation is carried out by passing the mud effluent through a multi-stage cyclone. 12. The method according to claim 9, wherein the separation is carried out by filtration, standing, or the use of an antisolvent. 13. The method of claim 12, wherein B filtration is stepwise and separates the added catalyst in preference to the decomposition catalyst. 14. A method according to any of claims 4 to 7 and 9 to 13, wherein the recovered catalyst is regenerated prior to recycling. b At least 90% by weight of the added catalyst contained in the reading streamer
The method according to claim 6, characterized in that: 16. The method according to any one of claims 1 to 15, wherein the hood reaction tower is a riser reaction tower. 17. The method according to any one of claims 1 to 16, wherein the n-cracking raw material is heavy oil. 2. A method according to any one of claims 1 to 17, wherein the decomposition catalyst comprises 5 to 50% by weight of synthetic faujasite dispersed in an inorganic oxide matrix. B. A method according to any one of claims 1 to 18, wherein the added catalyst comprises 10 to 40% by weight of zeolite having the structure of zeolite ZsM-5 composited with an amorphous binder.