RU2580829C2 - Method and apparatus for catalytic cracking for producing propylene - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a catalytic cracking method for producing propylene. Method involves supply of heavy oil stock and first catalyst of catalytic cracking in first elevator-reactor for catalytic cracking reaction; separation of obtained hydrocarbon flow and obtained coked catalyst in separator at end of first lift-reactor; supply of hydrocarbon flow separation in following products separation system; or supply of coked catalyst for steam directly into steamer, or first, supply of coked catalyst in reactor with fluidised bed and then fed into a steamer for steam; supply of steamed catalyst in regenerator for regeneration; wherein said first catalytic cracking catalyst contains shape-selective zeolite with average pore size less than 0.7 nm; supply of cracking of heavy oil stock in second lift-reactor; contacting with second catalyst of catalytic cracking, introduced in second lift-reactor for conducting reaction; wherein said second catalytic cracking catalyst contains shape-selective zeolite with average pore size less than 0.7 nm; supply of light hydrocarbons in second lift-reactor at point after supply of cracking of heavy oil material; mixing of light hydrocarbons with a mixture formed at contact and reactions of cracking of heavy oil raw material and second catalytic cracking catalyst and reaction; wherein said light hydrocarbons include C4 hydrocarbons and/or gasoline fraction, obtained in said system of separation products; supply of hydrocarbon flow and catalyst obtained after reaction in second lift-reactor with fluidised bed reactor connected in series with second lift-reactor for conducting reaction; supply of obtained hydrocarbon flow after reaction in reactor with fluidised bed for separation in products separation system; introduction of produced coked catalyst in a steamer for steam and then feeding steamed catalyst regeneration in regenerator.

EFFECT: said method is effective for producing propylene and provides good conversion of heavy oil raw material, high yield of propylene and butylene and good selectivity of formation of dry gas and coke, invention also relates to an apparatus.

19 cl, 4 tbl, 5 ex, 1 dwg

Description

Technical field

The present invention relates to a method for catalytic cracking, in particular to a method for catalytic cracking of heavy petroleum feedstocks for producing propylene.

BACKGROUND OF THE INVENTION

Catalytic cracking of heavy petroleum feedstocks is an important way to produce lower olefins, such as ethylene, propylene and butylene. Industrial methods for catalytic cracking of heavy petroleum feedstocks to produce lower olefins include catalytic cracking technology that aims to maximize propylene yield and catalytic pyrolysis technology that aims to maximize ethylene yield. For these two technologies, a configuration of a single elevator reactor or a combination of a single fluidized bed reactor and a special catalyst are used to carry out the reaction at a higher temperature. Although both of these technologies can increase the yield of lower olefins, such as ethylene and propylene, the yield of dry gas and coke is relatively large and therefore it is very difficult to further increase the yield of propylene.

CN 1,140,608 C (corresponding to US 6,059,958 A) discloses a method for cooling a regenerated catalyst, i.e. cooling a portion of the regenerated catalyst. A portion of the cooled regenerated catalyst and the non-cooled hot regenerated catalyst are mixed before being fed to the elevator reactor. A relatively low temperature mixed catalyst is contacted with a hydrocarbon stream to carry out the reaction. Another portion of the cooled regenerated catalyst is returned to the regenerator to control the regeneration temperature. This method does not say anything about increasing the yield of propylene.

CN 1081222 C (corresponding to US 6495028 B1) discloses a catalytic cracking method for reducing the olefin content of liquefied gas and gasoline. In this method, it is proposed in one elevator reactor or in a combination of an elevator reactor with a fluidized bed of catalyst to supply a preheated hydrocarbon stream to the lower part of the elevator reactor for contact with the catalyst. The reacted hydrocarbon stream flows up to the middle or upper part of the elevator reactor for contact and reaction with the cooled catalyst. The reaction stream leaves the reaction system through a catalyst unloading elevator to separate the resulting products. Coke is burned out from the spent catalyst for regeneration at high temperature and divided into two parts. One part enters the lower part of the elevator reactor, and the other is cooled and then fed to the middle or upper part of the elevator reactor. This method is not convenient for the production of propylene and other lower olefins.

CN 1,428,402 A discloses a combined catalytic cracking process, which comprises feeding 10-80% by weight of regenerated catalyst after cooling to a flow-circulation fluidized bed reactor for contact and reaction with a gasoline feed. After the reaction, the spent catalyst is fed into the stripping zone of the flow-circulation fluidized bed reactor for stripping. Then, 40-90 wt.% Of the stripped catalyst is returned to the reaction zone for reuse, and the rest is sent to the zone before being fed to the reactor with heavy oil feedstocks and mixed with uncooled hot regenerated catalyst for subsequent contact and reaction with heavy hydrocarbons. In this method, the yield of propylene is relatively low, and nothing is said about increasing the yield of propylene and reducing the yield of dry gas.

CN 1177020 C discloses a modified method and apparatus for processing low quality gasoline. In this method, it is proposed to cool the regenerated catalyst to 300 ° C-500 ° C and then direct it to the stripping section for mixing with the spent catalyst and contacting it in countercurrent with low-quality gasoline. The content of olefin and sulfur in gasoline can be reduced, and the RON index of gasoline can be increased. Nothing is said about increasing the yield of propylene.

CN 101074392 A discloses a method for producing propylene and diesel fuel in a two-section catalytic airlift reactor with a catalyst based on form-selective molecular sieves and using heavy petroleum hydrocarbons or various animal and vegetable oils as raw materials containing hydrocarbons. The specified method leads to a low yield of propylene and low conversion of heavy oil feedstocks.

SUMMARY OF THE INVENTION

The aim of the present invention is to eliminate the disadvantages of the prior art in the production of propylene by catalytic cracking and to propose a catalytic cracking method for producing propylene with an increased yield and low selectivity for the formation of dry gas. Specifically, the present invention provides a catalytic cracking method for producing propylene, comprising:

(1) feeding heavy oil feed and a first catalytic cracking catalyst to a first elevator reactor for carrying out a catalytic cracking reaction; separating the resulting hydrocarbon stream and the resulting coked catalyst in a separator at the end of the first elevator reactor; supplying a hydrocarbon stream for separation to the next product separation system; either direct supply of the coked catalyst to the steamer for steaming, or first the supply of coked catalyst to the fluidized bed reactor and then to the steamer for steaming; feeding the stripped catalyst to a regenerator for regeneration; wherein said first catalytic cracking catalyst comprises a form-selective zeolite with an average pore size of less than 0.7 nm;

(2) feeding cracked heavy oil feed to a second elevator reactor; contacting a second catalytic cracking catalyst introduced into the second elevator reactor to carry out the reaction; wherein said second catalytic cracking catalyst contains a form-selective zeolite with an average pore size of less than 0.7 nm;

(3) supplying light hydrocarbons for the reaction to the second elevator reactor at a point located after the point of introduction of the cracked heavy oil feed; mixing light hydrocarbons with a mixture formed by contacting with a catalyst and reacting a cracked heavy oil feed and a second catalytic cracking catalyst;

moreover, these light hydrocarbons contain C4 hydrocarbons and / or a gasoline fraction obtained in the specified product separation system;

(4) supplying the hydrocarbon stream and catalyst after the reaction to a second fluidized bed reactor in series with a second elevator reactor;

(5) after the reaction in a fluidized bed reactor, feeding the resulting hydrocarbon stream for separation into a product separation system; feeding the obtained coked catalyst to a stripping column for stripping, and then feeding the stripped catalyst for regeneration to the regenerator.

In one embodiment, the present invention provides a catalytic cracking process for producing propylene, which comprises:

(1) feeding heavy oil feed and a first catalytic cracking catalyst to a first elevator reactor for carrying out a catalytic cracking reaction;

moreover

the temperature at the outlet of the elevator reactor is approximately 530 ° C,

reaction time about 3 seconds;

the ratio of catalyst / raw material is about 10.7 wt./mass.,

the ratio of atomizing water vapor and heavy crude oil is about 8 wt.%;

separating the obtained hydrocarbon stream and the obtained coked catalyst in a separator at the end of the first elevator reactor; supplying a hydrocarbon stream for separation to the next product separation system; either direct supply of the coked catalyst to the steamer for steaming, or first the supply of coked catalyst to the fluidized bed reactor and then to the steamer for steaming; supply for regeneration of the stripped catalyst in the regenerator; wherein said first catalytic cracking catalyst comprises a form-selective zeolite with an average pore size of less than 0.7 nm;

(2) supplying the cracked heavy oil feed to a second elevator reactor comprising a second catalytic cracking catalyst placed in a second elevator reactor to carry out the reaction; wherein said second catalytic cracking catalyst contains a form-selective zeolite with an average pore size of less than 0.7 nm;

moreover

the temperature of the catalyst at the entrance to the second elevator reactor is about 695 ° C; the temperature at the outlet of the second elevator reactor is approximately 540 ° C,

the mass ratio of cracked heavy crude oil and heavy crude oil is approximately 5: 100;

the cracked heavy oil feed point is located at the bottom of the second elevator reactor;

the total reaction time of the cracked heavy oil feed in the elevator reactor is approximately 1.30 sec;

the ratio of spray steam and cracked heavy petroleum feed is about 10 wt.%;

a catalyst / cracked heavy oil feed ratio of about 33.3 w / w .;

(3) feeding the gasoline fraction as light hydrocarbons to the second elevator reactor at a point located after the cracked heavy oil feed; mixing the light hydrocarbons with the mixture obtained by contacting the catalyst and reacting the cracked heavy oil with a second catalytic cracking catalyst, and carrying out the reaction;

moreover

the reaction time of the cracked heavy petroleum feed to contact with light hydrocarbons is approximately 0.3 sec;

the reaction temperature of the cracked heavy petroleum feed to contact with light hydrocarbons is about 655 ° C;

the amount of coke on the catalyst after initial contact with light hydrocarbons is approximately 0.23 wt.%;

the mass ratio of light hydrocarbons and heavy crude oil is about 12: 100;

the ratio of catalyst / light hydrocarbons is approximately 13.9 wt./mass.,

the reaction time of light hydrocarbons in the elevator reactor is approximately 1.00 sec;

the ratio of atomizing water vapor and light hydrocarbons is about 15 wt.%; said light hydrocarbons include a gasoline fraction obtained in said product separation system;

(4) feeding the hydrocarbon stream and the catalyst after the reaction in the second elevator reactor to a fluidized bed reactor connected in series with the second elevator reactor to carry out the reaction;

moreover

the temperature of the catalyst layer is about 530 ° C; hourly space velocity in the layer of about 10 h ^-1 ;

(5) after the reaction in a fluidized bed reactor, feeding the resulting hydrocarbon stream for separation into a product separation system; feeding the obtained coked catalyst to a stripping column for stripping; and then feeding the stripped catalyst to a regenerator for regeneration.

In another embodiment, the present invention provides a catalytic cracking method for producing propylene, which includes:

(1) feeding heavy oil feed and a first catalytic cracking catalyst to a first elevator reactor for carrying out a catalytic cracking reaction; moreover

the temperature at the outlet of the elevator reactor is approximately 560 ° C,

reaction time about 3 seconds;

the ratio of catalyst / raw material is about 11.7 wt./mass.,

the ratio of atomizing water vapor and heavy crude oil is about 8 wt.%;

separating the obtained hydrocarbon stream and the obtained coked catalyst in a separator at the end of the first elevator reactor; supplying a hydrocarbon stream for separation to the next product separation system; either direct supply of the coked catalyst to the steamer for steaming, or first the supply of coked catalyst to the fluidized bed reactor and then to the steamer for steaming; supply for regeneration of the stripped catalyst in the regenerator; wherein said first catalytic cracking catalyst comprises a form-selective zeolite with an average pore size of less than 0.7 nm;

(2) supplying the cracked heavy oil feed to a second elevator reactor comprising a second catalytic cracking catalyst placed in a second elevator reactor to carry out the reaction; wherein said second catalytic cracking catalyst contains a form-selective zeolite with an average pore size of less than 0.7 nm;

moreover

the temperature of the catalyst at the entrance to the second elevator reactor is about 655 ° C;

the temperature at the outlet of the second elevator reactor is approximately 540 ° C,

the mass ratio of cracked heavy crude oil and heavy crude oil is approximately 5: 100;

the cracked heavy oil feed point is located at the bottom of the second elevator reactor;

the total reaction time of the cracked heavy petroleum feed in the elevator reactor is approximately 1.10 sec;

the ratio of spray steam and cracked heavy petroleum feed is about 10 wt.%;

a catalyst / cracked heavy oil feed ratio of about 34.5 w / w .;

(3) supplying the gasoline fraction and C4 hydrocarbons as light hydrocarbons to the second elevator reactor in the same amount after feeding the cracked heavy oil feed; mixing light hydrocarbons with a mixture obtained by contact and reaction of a cracked heavy petroleum feed and a second catalytic cracking catalyst, and carrying out a reaction, wherein

the reaction time of the cracked heavy petroleum feed to contact with light hydrocarbons is approximately 0.5 sec;

the reaction temperature of the cracked heavy petroleum feed to contact with light hydrocarbons is about 620 ° C;

the amount of coke on the catalyst after initial contact with light hydrocarbons is about 0.16 wt.%;

the reaction time of light hydrocarbons in the elevator reactor is approximately 0.60 sec;

the mass ratio of gasoline fraction to heavy oil feed is about 12: 100;

the ratio of catalyst / gasoline fraction of approximately 14.4 wt./mass.,

the ratio of atomizing water vapor and gasoline fraction of about 10 wt.%;

the mass ratio of the C4 fraction and heavy oil feed is about 8: 100;

the ratio of catalyst / hydrocarbons in the C4 fraction is about 21.6 wt./mass .;

the ratio of atomizing water vapor and fraction C4 is about 5 wt.%;

said light hydrocarbons contain C4 hydrocarbons and / or a gasoline fraction obtained in said product separation system;

(4) feeding the hydrocarbon stream and the catalyst after the reaction in the second elevator reactor to the fluidized bed reactor, connected in series with the second elevator reactor, for the reaction;

moreover

the temperature of the catalyst layer is about 550 ° C;

hourly space velocity in the layer of about 6 h ^-1 ;

(5) after the reaction in a fluidized bed reactor, the separation of the resulting hydrocarbon stream into a product separation system is fed; feeding the obtained coked catalyst to a stripping column for stripping; and then feeding the stripped catalyst to a regenerator for regeneration.

In another embodiment, the present invention provides a catalytic cracking method for producing propylene, which includes:

1) the supply of heavy petroleum feedstock and a first catalytic cracking catalyst to a first elevator reactor for carrying out a catalytic cracking reaction; moreover

the temperature at the outlet of the elevator reactor is approximately 500 ° C,

reaction time about 4 seconds;

the ratio of catalyst / raw material is about 7 wt./mass.,

the ratio of atomizing water vapor and heavy crude oil is about 5 mass.

separating the obtained hydrocarbon stream and the obtained coked catalyst in a separator at the end of the first elevator reactor; supplying a hydrocarbon stream to a separation system to the next product separation system, or directly supplying a coked catalyst to a stripping steamer, or first feeding a coked catalyst to a fluidized bed reactor and then to a steaming steamer; feeding the stripped catalyst to a regenerator for regeneration; wherein said first catalytic cracking catalyst comprises a form-selective zeolite with an average pore size of less than 0.7 nm;

(2) supplying the cracked heavy oil feed to a second elevator reactor comprising a second catalytic cracking catalyst placed in a second elevator reactor to carry out the reaction; wherein said second catalytic cracking catalyst contains a form-selective zeolite with an average pore size of less than 0.7 nm;

moreover

the temperature of the catalyst at the entrance to the second elevator reactor is about 695 ° C;

the temperature at the outlet of the second elevator reactor is approximately 520 ° C,

the mass ratio of cracked heavy crude oil and heavy crude oil is approximately 20: 100;

the feed point of the cracked heavy petroleum feed is located at the bottom of the second elevator reactor;

the total reaction time of the cracked heavy oil feed in the elevator reactor is approximately 0.80 sec;

the ratio of spray steam and cracked heavy petroleum feed is about 5 wt.%;

a catalyst / cracked heavy oil ratio of about 8.3% w / w .;

(3) feeding the gasoline fraction as light hydrocarbons to a second elevator reactor at a point located after the feed point of the cracked heavy oil feed; mixing the light hydrocarbons with the mixture obtained by contact and reaction of the cracked heavy petroleum feed and a second catalytic cracking catalyst, and carrying out the reaction,

moreover

the reaction time of the cracked heavy petroleum feed to contact with light hydrocarbons is approximately 0.1 sec;

the reaction temperature of the cracked heavy petroleum feed to contact with light hydrocarbons is about 595 ° C;

the amount of coke on the catalyst after initial contact with light hydrocarbons is approximately 1.23 wt.%;

the reaction time of light hydrocarbons in the elevator reactor is approximately 0.60 sec;

the mass ratio of light hydrocarbons and heavy crude oil is about 6: 100;

the ratio of catalyst / light hydrocarbons is approximately 27.7 wt./mass.

the reaction time of light hydrocarbons in the elevator reactor is about 0.7 sec;

the ratio of atomizing water vapor and light hydrocarbons is about 20 wt.%;

said light hydrocarbons contain a gasoline fraction obtained from said product separation system;

(4) supplying a hydrocarbon stream and a catalyst after the reaction in the second elevator reactor to a fluidized bed reactor connected in series with the second elevator reactor for the reaction;

moreover

catalyst bed temperature of about 510 ° C;

hourly space velocity in the layer of about 12 h ^-1 ;

(5) after the reaction in a fluidized bed reactor, the separation of the resulting hydrocarbon stream into a product separation system is fed; introducing the obtained coked catalyst into a stripper for stripping; and then introducing the stripped catalyst into the regenerator for regeneration.

In another embodiment, the present invention provides a catalytic cracking method for producing propylene, which includes:

(1) feeding heavy oil feed and a first catalytic cracking catalyst to a first elevator reactor for carrying out a catalytic cracking reaction;

moreover

the temperature at the outlet of the elevator reactor is approximately 515 ° C,

reaction time about 2.5 seconds;

the ratio of catalyst / raw material is about 14 wt./mass.,

the ratio of atomizing water vapor and heavy crude oil is about 10 wt.%;

separating the obtained hydrocarbon stream and the obtained coked catalyst in a separator at the end of the first elevator reactor; supplying a hydrocarbon stream to a subsequent separation system; either direct supply of the coked catalyst to the steamer for stripping, or first supply of the coked catalyst to the fluidized bed reactor and then to the steamer for steaming; feeding the stripped catalyst to a regenerator for regeneration; wherein said first catalytic cracking catalyst comprises a form-selective zeolite with an average pore size of less than 0.7 nm;

(2) feeding cracked heavy oil feed to a second elevator reactor; contacting a second catalytic cracking catalyst located in a second elevator reactor to effect a reaction; wherein said second catalytic cracking catalyst contains a form-selective zeolite with an average pore size of less than 0.7 nm;

moreover

the temperature of the catalyst at the entrance to the second elevator reactor is about 695 ° C;

the temperature at the outlet of the second elevator reactor is about 530 ° C;

the mass ratio of cracked heavy crude oil and heavy crude oil is about 10: 100;

the entry point of the cracked heavy petroleum feed is located at the bottom of the second elevator reactor;

the total reaction time of the cracked heavy oil feed in the elevator reactor is approximately 0.95 sec;

the ratio of spray steam and cracked heavy petroleum feed is about 8 wt.%;

a catalyst / cracked heavy oil ratio of about 16.6 w / w;

(3) feeding the gasoline fraction as light hydrocarbons to a second elevator reactor at a point after the introduction of cracked heavy petroleum feed; mixing light hydrocarbons with the mixture obtained by contacting the catalyst and the reaction of cracked heavy petroleum feed, and the second catalytic cracking catalyst, and carrying out the reaction,

moreover

the reaction time of the cracked heavy petroleum feed to contact with light hydrocarbons is approximately 0.15 sec;

the reaction temperature of the cracked heavy petroleum feed to contact with light hydrocarbons is approximately 645 ° C;

the amount of coke on the catalyst after initial contact with light hydrocarbons is about 0.62 wt.%;

the reaction time of light hydrocarbons in the elevator reactor is approximately 0.60 sec;

the mass ratio of light hydrocarbons and heavy crude oil is about 15: 100;

the ratio of catalyst / light hydrocarbons is approximately 11.1 wt./mass.

the reaction time of light hydrocarbons in the elevator reactor is approximately 0.8 seconds;

the ratio of atomizing water vapor and light hydrocarbons is about 15 wt.%;

said light hydrocarbons contain a gasoline fraction obtained from said product separation system;

(4) supplying a hydrocarbon stream and a catalyst after the reaction in the second elevator reactor to a fluidized bed reactor connected in series with the second elevator reactor for the reaction;

moreover

catalyst bed temperature of about 520 ° C;

hourly space velocity in the layer of about 11 h ^-1 ;

(5) after the reaction in a fluidized bed reactor, feeding the resulting hydrocarbon stream to a separation system for separation of products; feeding the obtained coked catalyst to a stripping column for stripping; and then feeding the stripped catalyst to a regenerator for regeneration.

In another embodiment, the present invention provides a catalytic cracking method for producing propylene, which includes:

(1) feeding heavy oil feed and a first catalytic cracking catalyst to a first elevator reactor for carrying out a catalytic cracking reaction; moreover

the temperature at the outlet of the elevator reactor is approximately 570 ° C,

reaction time about 1.5 seconds;

the ratio of catalyst / raw material is about 10 wt./mass.,

the ratio of atomizing water vapor and heavy crude oil is about 10 wt.%;

separating the obtained hydrocarbon stream and the obtained coked catalyst in a separator at the end of the first elevator reactor; supplying a hydrocarbon stream to a subsequent separation system; either direct transfer of the coked catalyst to the steamer for stripping, or first feeding the coked catalyst to the fluidized bed reactor and then to the steamer for steaming; feeding the stripped catalyst to a regenerator for regeneration; wherein said first catalytic cracking catalyst comprises a form-selective zeolite with an average pore size of less than 0.7 nm;

(2) feeding cracked heavy oil feed to a second elevator reactor; contacting a second catalytic cracking catalyst placed in a second reaction elevator reactor; wherein said second catalytic cracking catalyst contains a form-selective zeolite with an average pore size of less than 0.7 nm;

moreover

the temperature of the catalyst at the entrance to the second elevator reactor is about 695 ° C;

the temperature at the outlet of the second elevator reactor is about 575 ° C;

the mass ratio of cracked heavy crude oil and heavy crude oil is approximately 3.5: 100;

the cracked heavy oil feed point is located at the bottom of the second elevator reactor;

the total reaction time of the cracked heavy oil feed in the elevator reactor is approximately 1.13 sec;

the ratio of spray steam and cracked heavy petroleum feed is about 10 wt.%;

a catalyst / cracked heavy oil ratio of about 47.5 w / w .;

(3) supplying the gasoline fraction as light hydrocarbons to the second elevator reactor at a point after feeding the cracked heavy oil feed; mixing the light hydrocarbons with the mixture obtained by contact and reaction of the cracked heavy petroleum feed and a second catalytic cracking catalyst, and carrying out the reaction,

moreover

the reaction time of the cracked heavy petroleum feed to contact with light hydrocarbons is approximately 0.43 sec;

the reaction temperature of the cracked heavy petroleum feed to contact with light hydrocarbons is about 675 ° C;

the amount of coke on the catalyst after initial contact with light hydrocarbons is about 0.22 wt.%;

the mass ratio of light hydrocarbons and heavy crude oil is about 12: 100;

the ratio of catalyst / light hydrocarbons is approximately 13.9 wt./mass.

the reaction time of light hydrocarbons in the elevator reactor is about 0.7 sec;

the ratio of atomizing water vapor and light hydrocarbons is about 15 wt.%;

said light hydrocarbons contain a gasoline fraction obtained from said product separation system.

(4) feeding the hydrocarbon stream and the catalyst after the reaction in the second elevator reactor to a fluidized bed reactor connected in series with the second elevator reactor to carry out the reaction;

moreover

catalyst bed temperature of about 570 ° C; hourly space velocity in the layer of about 7 h ^-1 ;

(5) after the reaction in a fluidized bed reactor, feeding the resulting hydrocarbon stream to a separation system for separation of products; feeding the obtained coked catalyst to a stripping column for stripping; and then feeding the stripped catalyst to a regenerator for regeneration.

In five embodiments, as shown above, the term “about” means a deviation of ± 10%, ± 8%, ± 6%, ± 5%, ± 4%, ± 3%, ± 2%, or ± 1%.

The present invention also provides apparatus for the method described above, which includes: a first elevator reactor, a second elevator reactor, a fluidized bed reactor, a stripper column, a catalyst unloader, a product separation system and a regenerator, the second elevator reactor and a fluidized reactor the bed are connected in series, and the fluidized bed reactor is connected to the stripping column and the catalyst unloading elevator, the first elevator reactor and the catalyst unloading elevator are connected to each other The regenerator is connected to the stripping column, first and second riser reactors, respectively, are connected to conduits catalysts. The first elevator reactor has an input for supplying petroleum feed. The second elevator reactor includes a reaction zone for cracked heavy petroleum feed, an input for supplying cracked heavy petroleum feed and an input for supplying light hydrocarbons, the feed for light hydrocarbons being located between the input of the cracked heavy petroleum feed and the outlet of the second elevator reactor; moreover, the specified reaction zone for cracked heavy crude oil is between the input of the cracked heavy crude oil and the input of light hydrocarbons.

The catalytic cracking method for producing propylene of this invention is based on combining two elevator reactors and a fluidized bed. As a result of the optimization of the method, the selection of a suitable catalyst and the selective conversion of various feedstocks, the method of the present invention can provide a relatively large conversion depth of heavy petroleum feedstocks and a relatively high yield of high-quality product. In this case, the outputs of dry gas and coke do not increase. The method of the present invention provides relatively high yields of propylene and butylene and relatively low dry gas and coke selectivity.

Description of drawings

Figure 1 is a flow diagram of the catalytic cracking method of the present invention, in which 1 is a first elevator reactor, 2 is a second elevator reactor, 3 is a stripping column, 4 is a fluidized bed reactor, 5 is a catalyst unloading elevator 6 is a product separation system, 7 is a regenerator, 8 is a pipeline for spent catalyst, 9 and 10 are pipes for regenerated catalysis pa, wherein the riser reactor 2 is connected in series with the reactor of the fluidized bed 4, connected in parallel with the riser reactor 1 via the discharge of the catalyst lift 5 and the fluidized bed reactor 4 and the stripper 3 are disposed above and below respectively and bonded to each other.

Best Modes for Carrying Out the Invention

In the catalytic cracking method for producing propylene according to the present invention, the heavy oil feed and the first catalytic cracking catalyst are loaded into a first elevator reactor in which the heavy oil feed is contacted with the first catalytic cracking catalyst to form a hydrocarbon stream and a coked catalyst. The hydrocarbon stream and coked catalyst are separated in a separator at the end of the first elevator reactor. The hydrocarbon stream is fed for separation to the next product separation system. The coked first catalytic cracking catalyst is introduced into a stripping column or into a fluidized bed reactor, as discussed below, preferably into a fluidized bed reactor. The separator at the end of the first lift reactor serves to separate the flow of hydrocarbons and coked catalyst after the reaction, which helps to reduce the yield of dry gas and prevents further conversions of the resulting lower olefins, in particular propylene. Preferably, the separator is a high-speed separator. You can use an existing high-speed separator. A preferred high speed separator is a primary cyclone separator.

The reaction conditions in the first elevator reactor include:

The reaction temperature (i.e., the temperature at the outlet of the elevator reactor) is 480-600 ° C, for example 500-570 ° C, about 500 ° C, about 515 ° C, about 530 ° C, about 560 ° C, and about 570 ° C;

The ratio of catalyst / hydrocarbons (mass ratio of catalyst to heavy oil feed) is 5-20, for example 7-15, i.e. about 7, about 10, about 10.7, about 11.7 and about 14;

The reaction time is 0.50-10 seconds, for example 1-4 seconds, i.e. about 1.5 seconds, about 2 seconds, about 2.5 seconds, about 3 seconds and about 4 seconds;

Spraying water vapor for heavy crude oil is used in a mass ratio of relatively heavy crude oil, equal to 2-50 wt.%, For example 5-10 wt.%, I.e. about 5 wt.%, about 8 wt.% and about 10 wt.%;

The reaction pressure is 0.15-0.3 MPa (abs), for example 0.2-0.25 MPa (abs).

The heavy petroleum feed of the present invention includes heavy hydrocarbons or hydrocarbon-rich animal or vegetable oils. These heavy hydrocarbons are selected from one or more petroleum hydrocarbons, mineral oils, and synthetic oils. These petroleum hydrocarbons are well known to those skilled in the art and include vacuum paraffin distillate, residual atmospheric distillate oil, a mixture of vacuum paraffin distillate and residual atmospheric distillation oil or other hydrocarbon oils obtained from secondary processing. These other hydrocarbons from the secondary treatment include one or more coke oven oil, deasphalted oil and furfural raffinate products. Said mineral oils include one or more oils from coal liquefaction, oil from sandstone and shale oil. Synthetic oils include fractional oils obtained by FT synthesis from coal, natural gas, or asphaltene. Said hydrocarbon-rich animal or vegetable oils are, for example, one or more animal or vegetable fats and oils.

According to the present invention, heavy crude oil typically has an initial boiling point above 270 ° C at atmospheric pressure and the first 5% of the distillate at atmospheric pressure has a boiling point above 300 ° C.

In the catalytic cracking method for producing propylene according to the present invention, the cracked heavy feed is fed into the second elevator reactor and brought into contact with the hot regenerated catalyst to carry out the reaction, and the resulting reaction mixture is transferred from the contact of the cracked heavy feed to this second catalytic cracking catalyst into the second elevator -reactor and there participates in the reaction for some time. After the reaction, it is brought into contact and mixed with light hydrocarbons, which are introduced into the second elevator reactor. The resulting mixture flows into the second elevator reactor and reacts, after which it leaves the second elevator reactor. The second elevator reactor may have one or more inlets for heavy oil feedstocks and / or one or more inlets for light hydrocarbons. In the case where the second elevator reactor has two or more inlets for heavy oil feedstocks, these inlets can be localized at the same level or at different levels. Said light hydrocarbons are fed at one or more points between the cracked heavy oil feed inlet to the second elevator reactor (the highest inlet) and the outlet to the second elevator reactor. Here, the zone between the feed of the cracked heavy oil feed to the second elevator reactor (the highest input) and the feed of light hydrocarbons to the second lift reactor (the lowest feed) is called the reaction zone of the cracked heavy oil feed (or the reaction section for the cracked heavy oil feed). The catalytic cracking reaction of the heavy oil feed is carried out in the reaction zone of the cracked heavy oil feed.

Here, the effective length of the second elevator reactor refers to the distance from the feed point of the cracked heavy oil feed to the second elevator reactor (highest input) to exit the second elevator reactor.

Here, the height of the feed point of light hydrocarbons refers to the distance from the feed point of light hydrocarbons to the second elevator reactor to the feed point of the cracked heavy petroleum feed to the second elevator reactor (highest input).

According to the present invention, it is preferable that the height of the feed point of light hydrocarbons is 1-99%, 2-90%, 3-80%, 4-70%, 5-60%, 5-50%, 5-40%, 5-30 %, 5-25%, 5-20%, 5-15% or 5-10% of the effective length of the second elevator reactor. In the reaction zone of the cracked heavy oil feed, the catalyst / hydrocarbon ratio in the reaction of cracked heavy oil feed (the mass ratio of the second catalytic cracking catalyst introduced into the second elevator reactor and the cracked heavy oil feed introduced into the second elevator reactor) is 5-50, for example, 8-48 or 20-48, i.e. about 8.3, about 16.6, about 33.3, about 34.3 and about 47.5; atomizing water vapor for cracked heavy petroleum feed is used in an amount of 5-15%, i.e. about 5%, about 8% and about 10% by weight of cracked heavy petroleum feed; the mass ratio of cracked heavy crude oil and heavy crude oil fed to the first elevator reactor is 0.01-0.35: 1, for example, 0.01-0.10: 1 and 0.01-0.20: 1, i.e. about 0.035: 1, about 0.05: 1, about 0.1: 1, about 0.2: 1; the reaction time of the cracked heavy oil feed in the presence of a second catalytic cracking catalyst in a second elevator reactor prior to contacting with light hydrocarbons (hereinafter referred to as the reaction time of the cracked heavy oil feed before contacting with light hydrocarbons, i.e., the reaction time of the cracked heavy oil feed in the reaction zone cracked heavy oil feed) is 0.1-1 sec, for example, 0.1-0.5 sec and 0.2-0.5 sec, i.e. about 0.1 sec, about 0.15 sec, about 0.3 sec, about 0.43 sec and about 0.5 sec; the temperature of the second catalytic cracking catalyst, which is introduced into the second elevator reactor for contact with the cracked heavy oil feed, is 600-720 ° C, for example, 650-700 ° C, for example 655-695 ° C; e.g. 655 ° C or 695 ° C.

In the second elevator reactor, before contact with light hydrocarbons, the reaction temperature of the cracked heavy oil feed (i.e., the reaction temperature of the cracked heavy oil feed in the reaction zone of the cracked heavy oil feed, defined as the temperature at the outlet of the reaction zone of the cracked heavy oil feed) is 580 -700 ° C, e.g. 595-675 ° C and 620-650 ° C, i.e. about 595 ° C, about 620 ° C, about 645 ° C, about 655 ° C, or about 675 ° C. According to this invention, the boiling point of the cracked heavy petroleum feed is in the range of 330-550 ° C or 350-500 ° C. The cracked heavy petroleum feed of the present invention may be a hydrocarbon fraction with a boiling point of 300-550 ° C or in a narrower range. For example, cracked heavy petroleum feedstocks include heavy hydrocarbons from the product separation system of the present invention, i.e. the largest part of the liquid product remaining after the separation of gas, gasoline and diesel fuel from the hydrocarbon stream supplied to the product separation system.

Cracked heavy crude oil is first fed to a second elevator reactor for contact and reaction with the hot regenerated catalyst. The mixed hydrocarbon stream resulting from the reaction is then contacted with light hydrocarbons.

On the one hand, the secondary conversion of heavy oil feedstock increases the conversion of heavy oil feedstock for the entire apparatus / method, and the fraction of cracked heavy oil feedstock is used to increase the propylene yield. On the other hand, coke resulting from cracking of heavy petroleum feedstock selectively closes the pore channels in the matrix and in wide-porous molecular sieves (for example, zeolite Y). Therefore, the properties of the catalyst can be adjusted. The catalytic function of the form-selective zeolite in the catalyst increases and the hydrogen transfer reaction, which proceeds in wide-porous molecular sieves (zeolite Y) and the catalyst matrix, is inhibited.

The amount of coke on the second catalytic cracking catalyst leaving the cracked heavy oil feed reaction zone (i.e., the amount of coke on the catalyst after initial contact with light hydrocarbons) is, for example, 0.1-1.5% or 0.1-0.5%, i.e. . about 0.16%, 0.22%, about 0.23%, about 0.62% and about 1.23% by weight of the catalyst.

The contact and reaction between the cracked heavy oil feed and the hot regenerated catalyst lowers the temperature of the catalyst system and creates favorable conditions for the efficient conversion of the gasoline fraction and / or C4 hydrocarbons enriched in olefins during the subsequent reaction. Therefore, the catalytic reaction method can be optimized and the selectivity of the formation of propylene can be increased, while the formation of dry gas can be inhibited.

In the catalytic cracking method for producing propylene according to the present invention, said light hydrocarbons are fed to a second elevator reactor after introducing the cracked heavy oil feed and are brought into contact with a mixed hydrocarbon stream at a temperature of 580-700 ° C, for example, 595-675 ° C and 620 -650 ° C, i.e. about 595 ° C, about 620 ° C, about 645 ° C, about 655 ° C, or about 675 ° C, and are obtained by the reaction of cracked heavy hydrocarbons and a second catalytic cracking catalyst. The catalyst / hydrocarbon ratio in the reaction of light hydrocarbons in the second elevator reactor (the mass ratio of the second catalytic cracking catalyst introduced into the second elevator reactor and the light hydrocarbons introduced in the second elevator reactor) is 5-40, i.e. about 11.1, about 13.9, about 27.7 and about 36, the temperature in the second elevator reactor (defined as the temperature at the outlet of the second elevator reactor) is 520-580 ° C, i.e. about 520 ° C, about 530 ° C, about 540 ° C, or about 575 ° C. Here, light hydrocarbons are hydrocarbons with a final boiling point of not higher than 250 ° C or 220 ° C.

Said light hydrocarbons include a gasoline fraction and / or C4 hydrocarbons. In a specific embodiment, said light hydrocarbons are a gasoline fraction and / or C4 hydrocarbons. In the case where these light hydrocarbons contain a gasoline fraction, the reaction conditions for the gasoline fraction in the second elevator reactor include: the ratio of catalyst / feed to the gasoline fraction in the second elevator reactor (mass ratio of catalyst introduced into the second elevator reactor and gasoline fractions) is 10-30, for example, 11-28 or 15-25, i.e. about 11.1, about 13.9, about 14.4, and about 27.7; reaction time is 0.1-1.5 sec, for example, 0.3-1.0 sec or 0.3-0.8 sec, i.e. about 0.6 sec, about 0.7 sec, about 0.8 sec, and about 1.0 sec; spray water vapor for gasoline is used in an amount of 5-30%, for example, 10-20%, i.e. about 10%, about 15% and about 20% by weight of gasoline feedstocks.

In the case where these light hydrocarbons include C4 hydrocarbons, the reaction conditions for C4 hydrocarbons in the second elevator reactor include: the catalyst / feed ratio of C4 hydrocarbons in the second elevator reactor (mass ratio of the catalyst introduced into the second elevator reactor and hydrocarbons C4) is 12-40, for example, 17-30, i.e. about 21.6; the reaction time of C4 hydrocarbons in the second elevator reactor is 0.5-2.0 sec, for example, 0.5-1.5 sec, i.e. about 0.6 sec; atomizing water vapor for C4 hydrocarbons is used in an amount of 1-8%, for example 3-6%, i.e. about 5% by weight of the starting hydrocarbons C4. The mass ratio of light hydrocarbons fed to the second elevator reactor and heavy crude oil is 0.05-0.5: 1, for example, 0.05-0.3: 1, i.e. about 0.06: 1, about 0.12: 1, about 0.15: 1 and about 0.20: 1.

In the catalytic cracking method for producing propylene according to this invention, the hydrocarbon stream and catalyst after reaction in a second elevator reactor are fed to a fluidized bed reactor for subsequent reaction. The reaction conditions in the fluidized bed reactor include: a reaction temperature of 500-580 ° C, for example 510-570 ° C and 510-560 ° C, i.e. about 510 ° C, about 520 ° C, about 530 ° C, about 550 ° C, or about 570 ° C; the mass hourly space velocity in the reaction (relative to the total supply of hydrocarbon feed to the fluidized bed reactor) is 1-35 / hour, for example, 3-30 / hour, i.e. about 6 / hour, about II hour, about 10 / hour, about 11 / hour and about 12 / hour; reaction pressure 0.15-0.3 MPa (abs), e.g. 0.2-0.25 MPa (abs), i.e. about 0.21 MPa (abs).

In the catalytic cracking method for producing propylene according to this invention, the light hydrocarbons fed to the second elevator reactor comprise or comprise a gasoline fraction and / or C4 hydrocarbons, for example, an olefin-rich gasoline fraction and / or C4 olefin-rich hydrocarbons. The specified gasoline fraction includes the gasoline fraction obtained in this apparatus (obtained in the specified product separation system), and the gasoline fraction obtained in other apparatus. The gasoline fraction obtained in other equipment can be selected from one or more types of crude catalytic cracking gasoline, stabilized catalytic cracking gasoline, coke gasoline, light cracked gasoline and gasoline fractions obtained by other methods of refining and chemical oil refining. Olefins in olefin-rich gasoline feedstocks comprise 20-95 mass%, for example, 35-90 mass%, preferably 50 mass% or more. The specified gasoline feedstock can be a gasoline fraction in the full range of boiling points with a final boiling point of not higher than 204 ° C, for example, a gasoline fraction boiling in the range of 30-204 ° C and also in a narrower range, for example, a gasoline fraction boiling in the range 30-140 ° C, preferably 30-85 ° C or in an even narrower range.

The mass ratio of the specified gasoline fraction introduced into the specified second lift reactor, and the specified heavy oil feed introduced into the specified first lift reactor is 0.05-0.20: 1, preferably 0.08-0.15: 1. The mass ratio of the gasoline fraction fed to the second elevator reactor and the heavy oil feed to the first elevator reactor is 0.05-0.20: 1, for example, 0.06-0.15: 1 or 0.08-0.15: 1, i.e. about 0.06: 1, about 0.12: 1 and about 0.15: 1. Preferably, said gasoline fraction is an olefin-rich gasoline fraction, more preferably an olefin-rich gasoline fraction obtained in this apparatus.

C4 hydrocarbons are low molecular weight hydrocarbons that contain mainly C4 fractions and are in a gaseous form at ordinary temperature (for example, 0-20 ° C) and atmospheric pressure (such as 1 atm), and include alkanes, olefins and alkynes with 4 atoms carbon. C4 hydrocarbons can be a gaseous hydrocarbon stream enriched in a C4 fraction obtained in this apparatus, as well as a gaseous hydrocarbon stream enriched in a C4 fraction obtained in another apparatus, preferably a C4 fraction obtained in this apparatus. Preferably, said C4 hydrocarbons are an olefin-rich C4 fraction with a C4 olefin content of more than 50 wt.%, Preferably more than 60 wt.%, More preferably more than 70 wt.%.

Preferably, said light hydrocarbons contain a gasoline fraction containing or not containing C4 hydrocarbons, the mass ratio of C4 hydrocarbons and gasoline fraction being 0-2: 1, for example, 0-1.2: 1 or 0-0.8: 1, i.e. . about 2: 3. In the case where light hydrocarbons contain C4 hydrocarbons, the mass ratio of C4 hydrocarbons introduced into the second elevator reactor and the heavy oil feed is 0.05-0.3: 1, for example, 0.05-0.15: 1, i.e. approximately 0.08: 1.

The medium in the zone in front of the elevator reactor can be selected from one or several options - water vapor, C1-C4 hydrocarbons or traditional catalytic cracking dry gas; preferably steam and / or olefin-rich fraction C4. The zone in front of the elevator reactor refers here to the working zone in which the carrier medium changes the movement of the regenerated catalyst, accelerating it, in the vertical direction along the elevator reactor and puts the catalyst in a state of relatively random distribution in the flow in the radial direction of the elevator reactor (i.e. in the ideal displacement mode).

In the catalytic cracking method for producing propylene according to the present invention, the heavy petroleum feedstock and the cracked heavy feedstock are fed independently to the riser reactors at a point inside, before or after the zone before the lift in the direction from the entrance to the lift reactor (lowest) to the exit from the elevator reactor (the highest).

According to the present invention, the lower part of the elevator reactor refers to the position near and after the zone before lifting relative to the direction from the entry into the elevator reactor (lowest) to the exit of the elevator reactor (highest).

In the catalytic cracking method for producing propylene according to the present invention, a hydrocarbon stream is separated from the coked catalyst in a separator at the end of the first elevator reactor. This hydrocarbon stream is further separated to remove the entrained catalyst (as shown below) and fed to the next product separation system. After the reaction in the fluidized bed reactor, the hydrocarbon stream is separated in a catalyst unloading elevator to remove entrained catalyst and then fed to the next product separation system. In a product separation system, a hydrocarbon stream is separated into cracked gas, cracked gasoline, light recycle cracked gas oil and cracked heavy hydrocarbons. The specified product separation system is well known in the art, and the present invention does not contain any specific limitations for this system.

In the catalytic cracking method for producing propylene according to the present invention, a coked catalyst separated in a separator at the end of the first elevator reactor can be introduced directly into the stripper for stripping, or first introduced into a fluidized bed reactor and mixed with a fluidized bed reactor catalyst and then sent in a stripping column for steaming. It is preferable to first introduce it into the fluidized bed reactor and then into the stripper for stripping. The cracking catalyst after the fluidized bed reactor is fed to a stripper for stripping. Two catalyst streams from the first and second elevator reactors are stripped in the same stripping column. The stripped catalyst is sent to a regenerator for regeneration. The regenerated catalyst is introduced into the first elevator reactor and the second elevator reactor for reuse.

In the catalytic cracking method for producing propylene according to the present invention, it is preferable to supply steam for steam and a stream of stripped hydrocarbons to the lower part of the fluidized bed reactor and taken through a fluidized bed reactor. Therefore, to increase the yield of propylene and to reduce the outputs of dry gas and coke, it is possible to reduce the partial pressure of the hydrocarbon stream and the residence time of the hydrocarbon stream in the catalyst unloading elevator.

In the catalytic cracking method for producing propylene according to the present invention, said elevator reactor is selected from one or more elevator reactors of the same diameter, a reactor with the same speed and variable diameter, wherein the first elevator reactor and the second elevator reactor can be of the same or different type . The specified fluidized bed reactor is selected from one or more reactors, in particular from a fixed fluidized bed reactor, a fluidized bed reactor of small particles, a stationary fluidized bed reactor, a turbulent reactor, a fluidized bed reactor, and a circulating fluidized bed reactor reactor with a continuous filling of the catalyst.

In the catalytic cracking method for producing propylene according to the present invention, said catalysts (i.e., a first catalytic cracking catalyst and a second catalytic cracking catalyst) comprise a form-selective zeolite with an average pore size of 0.7 nm. A shape-selective zeolite with an average pore size of 0.7 nm is selected from one or more zeolites ZSM, ferrierite, chabazite, daciardite, erionite, zeolite A, epistilbit, lomontite and physically and / or chemically modified zeolites. ZSM zeolite is selected from one or more zeolites ZSM-5, ZSM-8, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-35, ZSM-38, ZSM-48, ZSP, ZRP and other zeolites with close structure. More information on ZSM-5 can be found in US Pat. No. 3,702,886. Said ZSM-5 zeolite may be HZSM-5 zeolite or ZSM-5 zeolite modified by elements, for example, one or more zeolites modified with P and transition metals. Said ZSM-5 zeolite modified with P and transition metals may be, for example, ZSP zeolite modified with P and Fe. Said ZRP zeolite may be an H-type ZRP zeolite or ZRP zeolite modified with elements, for example, P and rare earth metals. More information on ZRP zeolites can be found in US Pat. Nos. 5,232,675, CN 1,211,470 A and CN 1,611299 A.

Said catalyst comprising a form-selective zeolite with an average pore size of less than 0.7 nm may be one or more prior art catalysts or industrial catalysts or catalysts that are prepared by well-known prior art methods. The specified catalyst contains zeolite, inorganic oxides and optionally clay. For example, the specified catalyst contains 5-50 wt.% Zeolite, 5-95 wt.% Inorganic oxides and 0-70 wt.% Clay. Said zeolite includes a form-selective zeolite with an average pore size of less than 0.7 nm and optionally wide-porous zeolite. Formoselective zeolite with an average pore size of less than 0.7 nm contains 25-100 wt.%, Preferably 50-100 wt.% Of the active components. The specified wide-pore zeolite contains 0-75 wt.%, Preferably 0-50 wt.% Of the active components.

Said broad-porous zeolite is a porous zeolite with open channels of at least 0.7 nm and is selected from one or more zeolites Y, such as zeolite Y with rare earth elements, zeolite HY, ultrastable zeolite Y (USY) and ultrastable zeolite Y with rare earth elements (REUSY), Zeolite P and Zeolite L.

These inorganic oxides are used as binders and are selected from silica (SiO2) and / or alumina (Al2O3). Said clay is used as a matrix, i.e. carrier, and it is selected from kaolin and / or halloisite. In the catalytic cracking method for producing propylene according to the present invention, the catalyst containing a form-selective zeolite with an average pore size of less than 0.7 nm, which is used in the second elevator reactor, and the catalyst used in the first elevator reactor can be the same or different.

It is preferred that the catalysts used in the first and second elevator reactors are the same.

The catalytic cracking apparatus used in the catalytic cracking method for producing propylene according to the present invention includes at least a reaction zone, a regeneration zone, and a product separation system. The reaction zone preferably includes a combination of two elevator reactors and a fluidized bed, wherein one elevator reactor is connected (mainly coaxially) to the fluidized bed and a (coaxial) combination of said one elevator reactor and a fluidized bed are parallel to the other elevator reactor. Moreover, a (coaxial) sequential combination of said one riser reactor and a fluidized bed is connected (preferably coaxially) to the stripper. Catalytic cracking apparatus for producing propylene according to one embodiment of the present invention is shown in FIG. Said apparatus includes: a first elevator reactor 1, a second elevator reactor 2, a fluidized bed reactor 4, a steamer 3, a catalyst unloading elevator 5, a product separation system 6, and a regenerator 7. The elevator reactor 2 and the fluidized bed reactor 4 are connected in series and coaxial. The fluidized bed reactor 4 is connected to the stripper 3 and the catalyst unloading elevator 5. The elevator reactor 1 and the catalyst unloading elevator 5 are connected to each other. In the lower part of the elevator reactor 2 there is an input for supplying cracked heavy raw materials and a reaction zone for cracked heavy raw materials. The input for the cracked heavy feedstock is connected to the exit 34 for the cracked heavy feedstock from the product separation system 6 through the pipeline 36. The input for supplying light hydrocarbons is located between the input of the cracked heavy feedstock to the elevator reactor 2 and the outlet of the elevator reactor 2, and this input is connected with a pipeline of light hydrocarbons 24. The specified reaction zone of cracked heavy raw materials is located between the input of the cracked heavy raw materials and the input of light hydrocarbons. The lower part of the steamer 3 is connected to the regenerator 7 through the pipeline of spent catalyst 8. The regenerator 7 is connected to the lower part of the elevator reactor 1 through the pipeline of the regenerated catalyst 9. The regenerator 7 is connected to the lower part of the elevator reactor 2 through the pipeline of the regenerated catalyst 10.

In a coaxial serial combination of an elevator reactor and a fluidized bed, it is preferable that the outlet of the elevator reactor be equipped with a low pressure outlet distributor in which the pressure drop is less than 10 kPa.

Existing low pressure outlet valves, such as arched valves, can be used.

The following detailed description of preferred embodiments of the invention will be accompanied by a drawing. The following examples are only illustrative and do not limit the scope of the invention, which is determined by the attached claims and their equivalents. Specialists in this field will be apparent various changes and modifications of the described options that can be implemented without deviating from the idea and scope of the invention.

As shown in FIG. 1, the hot regenerated catalytic cracking catalyst fed to the reaction system is divided into two streams, one of which enters the lower part of the elevator reactor 1 through the regenerated catalyst conduit 9, and the other enters the lower part of the elevator reactor 2 through the pipeline of the regenerated catalyst 10. Both flows rise up under the action of the carrier medium from the pipelines 22 and 23.

The preheated heavy hydrocarbon feed (heavy hydrocarbons or animal or vegetable oils enriched in hydrocarbons) from line 20 and the spray steam from line 21 are mixed in a predetermined ratio and fed to the elevator reactor 1. The mixture of hydrocarbon stream and catalyst is separated in a quick separator (not shown) at the end of the elevator reactor 1 to form a hydrocarbon stream and a coked catalyst.

The heavy petroleum feed from the product separation system 6 in this apparatus is mixed through a pipe 36 with spray steam coming through a pipe 38 and fed to the bottom of the elevator reactor 2. The mixture is brought into contact with a hot regenerated catalyst that is fed through a pipe 10 for reaction . The mixture of hydrocarbon stream and catalyst rises up the elevator reactor 2. Next, at a point between the introduction of the cracked heavy feed and the outlet of the elevator reactor 2, the mixture is brought into contact with the mixture of light hydrocarbons from line 24 and spray water from the line 25 for reaction, and it continues to move along the elevator reactor 2. The mixture of all hydrocarbon streams and the catalyst enters the fluidized bed reactor 4 through the outlet distributor (not shown) of the elevator reactor 2 to continue the reaction and, finally, the post drawn through the catalyst discharge lifter for separating the catalyst from the hydrocarbon stream.

All hydrocarbon streams, including the hydrocarbon stream from the elevator reactor 1 and the hydrocarbon stream from the fluidized bed reactor 4, are collected in a cyclone separation system at the top of the catalyst unloading elevator and diverted via line 30 for feeding into the next separation system 6.

In the product separation system 6, the catalytic cracking products are separated into cracking gas (taken through line 31), cracked gasoline (taken through line 32), light recycle cracking gas oil (taken through line 33), cracked heavy hydrocarbons (taken through line 34) and suspension cracked hydrocarbons (diverted via pipeline 35).

The cracking gas discharged through line 31 is then separated and purified to form pure polymerizable propylene and an olefin-rich fraction C4, wherein said olefin-rich fraction C4 can be returned to a second elevator reactor 2 for conversion to propylene.

A portion or all of the cracked gas discharged via line 32 can be returned to the second elevator reactor 2 for further conversion. Alternatively, cracked gasoline can be separated into a light gasoline fraction and a heavy gasoline fraction, and some or all of the light gasoline fraction can be returned to the second elevator reactor 2 for further conversion.

Part or all of the cracked heavy hydrocarbons are returned via line 36 to the bottom of the elevator reactor 2 for further conversion.

The coked catalyst separated in the quick separator at the end of the lift reactor 1 is introduced into the fluidized bed reactor 4 and mixed with the catalyst from the lift reactor 2. After the reaction in the fluidized bed reactor 4, the mixed coked catalyst is fed to the steamer 3. Water vapor for the stripping is fed through line 37 and is brought into contact countercurrent with a mixed coked catalyst to maximize the steaming of the hydrocarbon stream carried away by the coked catalyst. The stripped hydrocarbon stream is then fed to the catalyst unloading elevator 5 through a fluidized bed reactor 4 and discharged along with other hydrocarbon streams through a conduit 30 from the catalyst unloading elevator 5.

The stripped catalyst is sent through a pipeline of spent catalyst 8 to a regenerator 7 for burning coke and regeneration. Oxygen-containing gas, such as air, is supplied at 7 through line 26. The regeneration fuel gas is led off through line 27. The regenerated catalysts are returned to the riser reactors 1 and 2 through the lines of the regenerated catalysts 9 and 10, respectively, for reuse.

In the above embodiment, the carrier medium is supplied to the elevator reactors 1 and 2 through pipelines 22 and 23, respectively. The following examples demonstrate the present invention.

Raw material B used in the examples and comparative examples is atmospheric racing heavy hydrocarbons, the properties of which are shown in Table 1. The MMS-2 catalyst from SINOPEC CATALYST QILU BRANCH COMPANY, the properties of which are shown in Table 2, was used. This catalyst contains a form-selective zeolite with an average pore size less than 0.7 nm.

Example 1

The experience of example 1 was carried out on a pilot installation. In this pilot installation, the inner diameter of the first elevator reactor was 16 mm and a height of 3800 mm, and the inner diameter of the second elevator reactor was 16 mm and a height of 3200 mm. The exit from the second elevator reactor was associated with a fluidized bed reactor with a diameter of 64 mm and a height of 600 mm. The pilot plant had a similar configuration as shown in FIG. The experience of example 1 was carried out in recycling mode, as shown below.

The hot regenerated catalyst was sent to the lower part of the elevator reactor 1 through the pipeline of the regenerated catalyst 9 from the regenerator 7, and it moved upward under the action of the flow of the carrier medium. Raw material B was preheated and mixed with atomizing water vapor. The mixture was fed into the riser reactor 1 through an inlet nozzle and brought into contact with the hot regenerated catalyst for catalytic cracking. The mixture of the hydrocarbon stream and the catalyst was transported upward through the elevator reactor 1 to a quick separator at the end of the elevator reactor 1 and separated into gas and solid. After separation, the hydrocarbon stream was sent to the product separation system 6 for separation into gas and liquid products. The catalyst was lowered into the fluidized bed reactor 4 by gravity. Another hot regenerated catalyst was fed through the pipeline of the regenerated catalyst 10 to the lower part of the elevator reactor 2, where it moved upward under the action of the carrier medium. He was brought into contact with a mixture of fractions of cracked heavy hydrocarbons with a boiling point of 350-500 ° C from the product separation system 6 and spray steam for the reaction. The mixture continued to move upward and then it was brought into contact with the recycle light gasoline fraction (with a boiling point of 30-85 ° C) fed through the nozzle at a level higher than the entry point of cracked heavy hydrocarbons by 300 mm, followed by reaction, this mixture moved upward and then entered the fluidized bed reactor 4 to continue the reaction. After the reaction, the hydrocarbon stream was separated from the catalyst carried to the catalyst discharge elevator, and then sent to the product separation system 6.

A coked catalyst (i.e., spent catalyst, including catalysts from the first and second elevator reactors) was introduced into the stripper 3 connected to the fluidized bed reactor from the bottom of the fluidized bed reactor. After steaming, the spent catalyst entered the regenerator 7 for contact with air and annealing the coke at high temperature to regenerate the catalyst. The regenerated catalyst was fed for reuse to both elevator reactors via regenerated catalyst pipelines. After stripping the hydrocarbon stream adsorbed on the spent catalyst using steam stripping, the stripped hydrocarbon stream was fed to the catalyst unloader to separate gas and solids.

The main working conditions and the results obtained in example 1 are shown in table 3.

Comparative Example 1

The experience of comparative example 1 was conducted on a pilot installation. In this pilot installation, two elevator reactors were used. The inner diameter of the first elevator reactor was 16 mm and a height of 3800 mm, and the inner diameter of the second elevator reactor was 14 mm and a height of 3800 mm. The difference from Example 1 was that there was no fluidized bed reactor at the outlet of the second elevator reactor. The basic configuration of comparative example 1 is shown in FIG. 1 of patent CN 101074392 A. Comparative example 1 also worked with recycling in much the same way as in example 1. The main operating conditions and results of comparative example 1 are shown in table 3.

Example 2

The experiment of Example 2 was carried out in the same manner as in Example 1, except that the C4 fraction of the recycle from the product separation system 6 was fed to the second elevator reactor and the corresponding operating conditions were established. The main operating conditions and results of example 2 are shown in table 3.

Example 3

The experience of example 3 was carried out on a pilot installation, as shown in figure 1. In this pilot plant operating in a continuous reaction-regeneration mode, the elevator reactor 1 had an inner diameter of 16 mm and a height of 3800 mm, and the elevator reactor 2 had an inner diameter of 16 mm and a height of 3200 mm. The exit from the elevator reactor 2 was connected to the fluidized bed reactor 3, which had an internal diameter of 64 mm and a height of 600 mm.

The feed was heavy hydrocarbons in an atmospheric race, and the catalyst was MMS-2.

The first hot regenerated catalyst was introduced into the lower part of the elevator reactor 1 through the regenerated catalyst pipeline 9 from the regenerator 7, where it was raised upward by the action of water vapor as a carrier medium and brought into contact with the feed B fed to the elevator reactor 1 via the pipeline 20 for the reaction. After the reaction, the hydrocarbon stream and the catalyst were sent to the discharge elevator of the catalyst 5 for separation. The separated hydrocarbon stream was fed into the product separation system 6, and the separated catalyst was introduced into the fluidized bed reactor 4. The second hot regenerated catalyst was fed through the regenerated catalyst pipeline 10 to the lower part of the elevator reactor 2, where it was moved upward by the action of water vapor as a carrier medium . He was brought into contact with a mixture of cracked heavy hydrocarbons with a boiling range of 300-550 ° C, introduced into the elevator reactor 2 through line 36 from the product separation system 6 along with atomizing water vapor through line 38 for the reaction. Cracked light gasoline (with a boiling point of 32-85 ° C) was fed into elevator reactor 2 at a level higher than the feed point of cracked heavy hydrocarbons by 300 mm to participate in the reaction. The reaction mixture moved upward through the elevator reactor and then entered the fluidized bed reactor connected to the elevator reactor through the outlet of the reactor. After the reaction in a fluidized bed reactor, a hydrocarbon stream carrying a portion of the catalyst enters the catalyst unloading elevator. Then, gas and solids were separated in a cyclone separation system on top of the catalyst discharge elevator. The hydrocarbon stream was sent via line 30 to the product separation system 6 for separation into gas and liquid products. After the reaction in a fluidized bed reactor, the coked catalyst (spent catalyst) fell into the steamer by gravity. After steaming the hydrocarbon stream adsorbed on the spent catalyst using steam steam, the stripped hydrocarbon stream was sent to the catalyst unloader to separate gas and solids.

After steaming, the spent catalyst entered the regenerator through the spent catalyst pipe 8 for contact with air and annealing the coke at high temperature to regenerate the catalyst. The regenerated catalyst was reused.

The main operating conditions and results of example 3 are shown in table 4.

Examples 4-5

According to example 1, the reaction conditions in examples 4-5 were set accordingly. The main operating conditions and results of examples 4-5 are shown in table 4.

Reference Example 2

The experiment in comparative example 2 was carried out as in example 2, except that cracked light gasoline was fed into the lower part of the riser reactor 2, and cracked heavy hydrocarbons were introduced into the lower part of the fluidized bed reactor 4. C4 fraction of the recycle from the product separation system 6 was introduced into the preliminary zone of the elevator reactor 2. The main operating conditions and results of comparative example 2 are shown in table 3.

Reference Example 3

The experiment in comparative example 3 was carried out according to example 1 with the exception that the light hydrocarbons were fed to the lower part of the elevator reactor 2, and the injection of cracked heavy hydrocarbons was at half maximum from the entrance of light hydrocarbons to the exit of the elevator reactor 2. The regenerated catalyst supplied by the catalyst conduit to the elevator reactor 2, first brought into contact with light hydrocarbons, and then with cracked heavy hydrocarbons fed to the elevator reactor 2 for reaction, and then sent for reaction to the reactor with psa fluidized bed 4. As can be seen from tables 3 and 4, the method of the present invention makes it possible to increase the yield of propylene and butylene, as well as significantly reduce the yield of coke and dry gas. The selectivity of dry gas formation (i.e., dry gas yield * × 100 / conversion rate) decreases. The method of the present invention provides an increased ability to convert heavy hydrocarbons with the desired distribution of products.

Table 1 Indicator Raw Material In Density / (g / cm ³ ) 0.8950 Refractive Index (nd70) 1.4888 Kinematic viscosity / (mm ² / s) at 80 ° C 34.92 at 100 ° C 09/20 Freezing temperature / ° C 48 w (residual carbon) /% 6.05 Elemental composition w (C / H) /% 86.34 / 13.10 w (S / N) /% 0.32 / 0.24 Group composition w (saturated hydrocarbons / aromatic 57.1 / 20.2 hydrocarbons) /% w (resin / asphaltene) /% 22.5 / 0.2 Metal Content / (μg / g) Ni / V 18.30 / 0.27 Distillation Intervals / ° C Initial Boiling Point (IBP) 278 5% 362 10% 393 thirty% 447 fifty% 503 fifty% 503 70% 539 (57.8) 90% 95% Note: w means mass in tables 1, 3 and 4.

table 2 Catalyst MMS-2 Chemical composition, wt.% Al ₂ O ₃ 49.2 Na ₂ O 0.072 Re ₂ O ₃ 0.61 Physical properties Total pore volume, ml / g 0.208 The volume of micropores, ml / g 0.024 Specific surface, m ² / g 155 The specific surface of the zeolite, m ² / g fifty The specific surface of the matrix, m ² / g 105 Bulk density, g / ml 0.72 Size distribution, φ% 0-20 microns 1.6 0-40 microns 14.2 0-80 microns 53.8 0-110 μm 72.6 0-149 μm 89.5 Microactivity, wt.% 66

Table 3 Example Number Example 1 Comparative Example 1 Example 2 Reference Example 2 Raw materials Raw Material In Raw Material In Raw Material In Raw Material In Reaction pressure, MPa (abs) 0.21 0.21 0.21 0.21 Regeneration temperature, ° C 700 700 700 00 First Lift Reactor Temperature at the outlet of the elevator reactor, ° C 530 530 560 550 The reaction time of the flow of hydrocarbons, s 3 3 3 2.5 The ratio of the catalyst / raw material, wt./mass. 10.7 10.7 11.7 12.4 The proportion of spray vapor (relatively fresh raw materials), wt.% 8 8 8 fifteen The combination of the second elevator reactor and the fluidized bed Second Lift Reactor The temperature of the catalyst entering the second elevator reactor, ° C 695 695 655 The temperature at the outlet of the second elevator reactor, ° C 540 540 540 560 Layer temperature, ° C 530 / 550 548 Mass hourly space velocity, h ^-1 10 / 6 5 Reaction conditions for cracked heavy hydrocarbons The proportion of cracked heavy hydrocarbons recycle (relatively fresh raw materials), wt.% 5 5 5 10 Cracked heavy hydrocarbon injection site The lower part of the second elevator reactor The lower part of the second elevator reactor The lower part of the second elevator reactor The lower part of the second elevator reactor The total reaction time of cracked heavy hydrocarbons in the elevator reactor, s 1.30 1.56 1.10 0 Total reaction time of cracked heavy hydrocarbons before contact with light hydrocarbons, s 0.3 0.3 0.5 0 The reaction temperature of cracked heavy hydrocarbons before contact with light hydrocarbons, ° C 655 655 620 The proportion of atomizing water vapor (relative to cracked heavy hydrocarbons), wt.% 10 10 10 10 Catalyst / Hydrocarbon Ratio for Cracked
heavy hydrocarbons, wt./mass. 33.3 33.3 34.5 The amount of coke on the catalyst after initial contact with light hydrocarbons, wt.% 0.23 0.23 0.16 Reaction conditions for light gasoline and fraction C4 The fraction fraction of C4 recycle (relatively fresh raw materials), wt.% / / 8 8 Place of input fraction C4 / / 300 mm from the point of entry of cracked heavy hydrocarbons Preliminary zone of the elevator reactor The ratio of catalyst / hydrocarbon fraction C4, wt./mass. / / 21.6 29th The reaction time of the fraction C4 in the elevator reactor, s / / 0.6 0.78 The proportion of atomizing water vapor (relative to fraction C4), wt.% / / 5 10 The proportion of light gasoline recycle (relatively fresh raw materials), wt.% 12 12 12 10 The final boiling point of light gasoline recycle, ° C 85 85 85 85 Light petrol injection point 300 mm from the injection site of cracked heavy hydrocarbons 300 mm from the injection site of cracked heavy hydrocarbons 300 mm from the injection site of cracked heavy hydrocarbons The lower part of the second elevator reactor The ratio of catalyst / hydrocarbons for light gasoline, wt./mass. 13.9 13.9 14.4 23 The reaction time of light gasoline in the elevator reactor, s 1.00 1.26 0.60 0.55 The proportion of atomizing water vapor (relatively light gasoline), wt.% fifteen fifteen 10 fifteen Catalyst MMS-2 MMS-2 MMS-2 MMS-2 Balance, w% H2-C2 4.97 5.05 7.85 8.15 C3-C4 37.66 35.66 45.23 44.93 C5 + cracked gasoline 05/29 05/28 10 p.m. 21.86 Cracked Light Recycling Hydrocarbons 13.68 15.83 11.09 10.84 Cracked Heavy Hydrocarbons 5.24 5.96 4.20 4.39 Coke 9.40 9.45 9.63 9.83 Total 100.00 100.00 100.00 100.00 Dry gas yield / conversion rate (selectivity for dry gas formation) 0.0613 0.0646 0.0927 0.0961 Coke yield / conversion rate (coke selectivity) 0.1159 0.1208 0.1137 0.1160 The yield of light hydrocarbons (relatively fresh raw materials), wt.% Ethylene 2.32 2.2 3.76 3.81 Propylene 16.64 14.69 23.78 23.38 All butylene 14.49 11.94 10.77 10.63

Table 4 Sample Numbers Example 3 Example 4 Reference Example 3 Example 5 Raw materials Raw Material In Raw Material In Raw Material In Raw Material In Reaction pressure, MPa (a) 0.21 0.21 0.21 0.21 Regeneration temperature, ° C 700 700 700 700 First Lift Reactor Temperature at the outlet of the elevator reactor, ° C 500 515 515 570 The reaction time of the hydrocarbon stream, s four 2.5 2.5 1.5 The ratio of catalyst / hydrocarbons, wt./mass. 7 fourteen fourteen 10 The proportion of atomizing water vapor (relatively fresh raw materials), wt.% 5 10 10 10 The combination of a second elevator reactor and a fluidized bed reactor The temperature of the catalyst at the entrance to the second elevator reactor, ° C 695 695 695 695 The temperature at the outlet of the second elevator reactor, ° C 520 530 530 575 Layer temperature, ° C 510 520 520 570 Mass hourly space velocity in the layer, h ^-1 12 eleven eleven 7 Reaction conditions for cracked heavy hydrocarbons The proportion of cracked heavy hydrocarbons recycle (relatively fresh raw materials), wt.% twenty 10 10 3.5 Cracked heavy hydrocarbon injection site The lower part of the second elevator reactor The lower part of the second elevator reactor At half maximum from the introduction of light gasoline to the exit from the second elevator reactor The lower part of the second elevator reactor The total reaction time of cracked heavy hydrocarbons in the elevator reactor, sec 0.80 0.95 0.40 1.13 The total reaction time of cracked heavy hydrocarbons before contact with light hydrocarbons, sec 0.10 0.15 / 0.43 The reaction temperature of cracked heavy hydrocarbons before contact with light hydrocarbons, ° C 595 645 / 675 The proportion of atomizing water vapor (relative to cracked heavy hydrocarbons), wt.% 5 8 8 10 The ratio of catalyst / hydrocarbons for cracked heavy hydrocarbons,
mass./mass. 8.3 16.6 16.6 47.5 The amount of coke on the catalyst after leaving the reaction zone of cracked heavy hydrocarbons, wt.% 1.23 0.62 / 0.22 Reaction conditions for light gasoline The fraction of light gasoline recycle (relative to fresh raw materials), wt.% 6 fifteen fifteen 12 The final boiling point of light gasoline recycle, ° C 85 85 85 85 Light petrol injection point 300 mm from the point of entry of cracked heavy hydrocarbons 300 mm from the point of entry of cracked heavy hydrocarbons The lower part of the second elevator reactor 300 mm from the injection site of cracked heavy hydrocarbons The ratio of catalyst / hydrocarbons for light gasoline, wt./mass. 27.7 11.1 11.1 13.9 The reaction time of light gasoline in the elevator reactor, sec 0.7 0.8 1.2 0.7 The proportion of atomizing water vapor (relatively light gasoline), wt.% twenty fifteen fifteen fifteen Catalyst MMS-2 MMS-2 MMS-2 MMS-2 Balance, w% H2-C2 3.25 4.23 4.35 8.40 C3-C4 31.54 35.00 33.55 42.27 C5 + cracked gasoline 33.81 31.24 30.83 24.65 Cracked Light Recycling Hydrocarbons 15.40 14.43 15.22 10.50 Cracked Heavy Hydrocarbons 6.83 5.83 6.53 4.14 Coke 9.17 9.57 9.52 10.04 Total 100.00 100.30 100.00 100.00 Dry gas yield / conversion rate (selectivity for dry gas formation) 0.0418 0.0530 0.0556 0.0984 Coke yield / conversion rate (selectivity
coke formation) 0.1179 0.1200 0.1217 0.1176 The yield of light hydrocarbons (relatively fresh raw materials), wt.% Ethylene 1.28 1.97 1.91 3.93 Propylene 07/14 15.76 14.97 10 p.m. All butylene 11.81 13.47 12.56 16.26 Note: in Tables 3 and 4, fresh feeds refer to heavy petroleum feedstock, i.e. raw material B in the examples of the present invention; w refers to mass. Reaction pressure refers to the pressure in the catalyst unloader.

Claims (19)

1. The method of catalytic cracking for propylene, which includes:
(1) feeding heavy oil feed and a first catalytic cracking catalyst to a first elevator reactor for carrying out a catalytic cracking reaction; separating the obtained hydrocarbon stream and the obtained coked catalyst in a separator at the end of the first elevator reactor; supplying a hydrocarbon stream for separation to the next product separation system; either supplying a coked catalyst for steaming directly to the steamer, or first feeding the coked catalyst to the fluidized bed reactor and then feeding it to the steamer for steaming; feeding the stripped catalyst to a regenerator for regeneration; wherein said first catalytic cracking catalyst comprises a form-selective zeolite with an average pore size of less than 0.7 nm;
(2) feeding cracked heavy oil feed to a second elevator reactor; contacting a second catalytic cracking catalyst introduced into the second elevator reactor to carry out the reaction; wherein said second catalytic cracking catalyst contains a form-selective zeolite with an average pore size of less than 0.7 nm;
(3) the supply of light hydrocarbons to the second elevator reactor at a point after the supply of cracked heavy petroleum feed; mixing light hydrocarbons with the mixture formed upon contact and reaction of the cracked heavy petroleum feed and a second catalytic cracking catalyst, and carrying out the reaction;
wherein said light hydrocarbons include C4 hydrocarbons and / or a gasoline fraction obtained in said product separation system;
(4) feeding the hydrocarbon stream and the catalyst obtained after the reaction in the second elevator reactor to a fluidized bed reactor connected in series with the second elevator reactor to carry out the reaction;
(5) feeding the resulting hydrocarbon stream after reaction in a fluidized bed reactor for separation into a product separation system; introducing the obtained coked catalyst into a steamer for steaming and then feeding the steamed catalyst for regeneration in the regenerator. 2. The method according to claim 1, in which the reaction temperature of the heavy crude oil in the first elevator reactor is 480-600 ° C, the catalyst / hydrocarbon ratio is 5-20, the reaction time is 0.50-10 sec, atomizing water vapor for the heavy crude oil is used in a mass ratio to heavy crude oil of 2-50 wt.% and the reaction pressure is 0.15-0.3 MPa (abs). 3. The method according to claim 1, in which the reaction temperature of the heavy oil feed in the first elevator reactor is 500-570 ° C, the catalyst / hydrocarbon ratio is 7-15, the reaction time is 1-4 seconds, atomizing water vapor for the heavy oil feed is used in a mass ratio to heavy crude oil of 5-10 wt.% and the reaction pressure is 0.2-0.25 MPa (abs). 4. The method according to claim 1, in which the contact time of the cracked heavy hydrocarbons and the second catalytic cracking catalyst before contact with light hydrocarbons in the second elevator reactor is 0.1-1 seconds, the catalyst / hydrocarbon ratio in the reaction of cracked heavy hydrocarbons is 5-50: 1, atomizing water vapor for cracked heavy petroleum feed is used in a weight ratio of 5-15 wt% relative to cracked heavy petroleum; and the temperature of the second catalytic cracking catalyst introduced into the second elevator reactor is 600-720 ° C. 5. The method according to claim 4, in which before contact with light hydrocarbons, the contact time of the cracked heavy hydrocarbons and the second catalytic cracking catalyst in the second elevator reactor is 0.1-0.5 seconds. 6. The method according to claim 4, in which the temperature of the second catalytic cracking catalyst fed to the second elevator reactor is 650-700 ° C. 7. The method according to claim 4, in which the ratio of catalyst / hydrocarbons in the reaction of cracked heavy hydrocarbons in the second elevator reactor is 20-48. 8. The method according to claim 1, in which the reaction temperature of the cracked heavy hydrocarbons in the second elevator reactor before contact with light hydrocarbons is 580-700 ° C. 9. The method of claim 8, in which the reaction temperature of the cracked heavy hydrocarbons before contact with light hydrocarbons is 595-675 ° C. 10. The method according to claim 4, in which the ratio of the catalyst / hydrocarbons in the reaction of light hydrocarbons in the second elevator reactor is 5-40. 11. The method according to claim 4, in which said light hydrocarbons are a gasoline fraction and / or C4 hydrocarbons, when said light hydrocarbons include a gasoline fraction, the reaction conditions of the gasoline fraction in the second elevator reactor include: catalyst to hydrocarbon ratio 10-30 , the reaction time is 0.1-1.5 seconds and spray water vapor for the gasoline fraction is used in a mass ratio with the gasoline fraction equal to 5-30 wt.%; in the case when these light hydrocarbons include C4 hydrocarbons, the operating conditions for the reaction of C4 hydrocarbons in the second elevator reactor include: a catalyst / hydrocarbon ratio of 12-40 and a reaction time of 0.50-2.0 seconds. 12. The method according to claim 4, in which the mass ratio of these cracked heavy hydrocarbons and the specified heavy crude oil is 0.01-0.35: 1; and the mass ratio of these light hydrocarbons and the specified heavy oil is 0.05-0.5: 1. 13. The method according to claim 4, in which the mass ratio of these cracked heavy hydrocarbons and the specified heavy oil is 0.01-0.10: 1 and the mass ratio of these light hydrocarbons and the specified heavy oil is 0.05-0.3: 1. 14. The method according to claim 4, in which the reaction temperature in the fluidized bed reactor is 500-580 ° C and the mass hourly space velocity is 1-35 / hour. 15. The method according to claim 4, in which the coked catalyst obtained in the first elevator reactor is introduced into the fluidized bed reactor. 16. The method according to claim 1, wherein said heavy oil feedstock is heavy hydrocarbons or hydrocarbon-rich animal or vegetable oils. 17. The method according to claim 1, wherein said cracked heavy hydrocarbons are a fraction with a boiling range of 300-550 ° C. or a narrower fraction obtained by separation in a product separation system. 18. The method according to claim 1, wherein said catalyst contains 5-50 wt.% Zeolite, 5-95 wt.% Inorganic oxides and 0-70 wt.% Clay, wherein said zeolite contains 25-100 wt.% Formoselective zeolite with an average pore size of less than 0.7 nm and 0-75 wt.% broad-porous zeolite. 19. A catalytic cracking device for producing propylene, including a first elevator reactor (1), a second elevator reactor (2), a fluidized bed reactor (4), a steamer (3), a catalyst unloading elevator (5), a product separation system ( 6) and a regenerator (7); moreover, the second elevator reactor (2) and the fluidized bed reactor (4) are connected in series and coaxially, the fluidized bed reactor (4) is connected to the steamer (3) and the catalyst unloading elevator (5), the first elevator reactor (1) and the catalyst unloading elevator (5) are connected to each other, the catalyst unloading elevator (5) and the product separation system are connected to each other; in the lower part of the lift reactor (2) there is an input for supplying cracked heavy raw materials and a reaction zone for cracked heavy raw materials, an input for cracked heavy raw materials is connected to the outlet (34) for cracked heavy raw materials from the product separation system (6) through a pipeline (36 ) for feeding cracked heavy raw materials from the product separation system (6), the regenerator (7) is connected to the steamer (3), the first elevator reactor (1) and the second elevator reactor (2), respectively, through the spent catalyst pipeline (8), pipeline for catalyst a (9) is connected to the first elevator reactor (1), the catalyst pipe (10) to the second elevator reactor (2); an input for light hydrocarbons is located between the input of the cracked heavy feedstock into the elevator reactor (2) and the outlet of the elevator reactor (2); the specified reaction zone for cracked heavy hydrocarbons is located between the input of the cracked heavy hydrocarbons and the input of light hydrocarbons.

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